Unresponsiveness of intrahepatic lymphocytes to bacterial superantigen: rapid development of suppressive Mac-1(high) cells in the mouse liver

We previously found that a small dose (2 microg per mouse) of staphylococcal enterotoxin B (SEB) induced early emerging unresponsiveness in intrahepatic-lymphocyte populations (IHLs). The purpose of this study was to reveal the inducing role of accessory cells involved in IHLs in this phenomenon. IHLs prepared at 3 to 24 hours after SEB injection failed to proliferate in response not only to SEB but also to SEA, representing ligand-nonspecific unresponsiveness, whereas spleen cells (SPCs) and mesenteric lymph-node cells showed transient proliferation. Unresponsiveness in IHLs was related to a deficit of their accessory cell function as measured by coculture of irradiated IHLs and antigen-specific, type 1 T-helper (Th1) clone cells. High levels of nitrite were detected in the culture supernatant. Supplement of N(G)-monomethyl-L-arginine lowered nitrite levels and concurrently restored the proliferative response of Th1 cells, indicating the involvement of nitric oxide in suppression. Adherent cells prepared from IHLs well reproduced these results. As shown by flow cytometry, Mac-1(high) Ia(+) cells, which mainly included F4/80(+) cells (macrophages) and a minor population of CD11c(+) cells (dendritic cells), increased in proportion in IHLs but not in SPCs at 6 to 24 hours. Depletion of Mac-1(high) cells from IHLs with antibody-coated magnetic beads recovered the proliferative response. Depleted Mac-1(high) cells had a monocytoid appearance. In immunostained sections, Kupffer cells came to highly express both Mac-1 and Ia at 12 hours. These results indicate that Mac-1(high)Ia(+) adherent cells, largely Kupffer cells activated by SEB, nonspecifically suppress the proliferation of Th1 cells via nitric oxide production before manifestation of ligand-specific unresponsiveness.

Vascularised fibular grafts

The results and complications of 104 vascularised fibular grafts in 102 patients are presented. Bony union was ultimately achieved in 97 patients, with primary union in 84 (84%). The mean time to union was 15.5 weeks (8 to 40). In 13 patients, primary union was achieved at one end of the fibula and secondary union at the other end. In these patients, the mean time to union was 31.1 weeks (24 to 40). Five patients failed to achieve union, with a resultant pseudarthrosis (3 patients) or amputation (2 patients).

There were various complications. Immediate thrombosis occurred in 14 cases. In two of 23 patients with osteomyelitis, infection recurred at two and six months after surgery, respectively. Both patients had active osteomyelitis less than one month before the operation. Bony infection occurred in a patient with a synovial sarcoma of the forearm one year after surgery. In 15 patients, 19 fractures of the fibular graft occurred after bony union, all except one within one year after union. In patients in whom an external fixator had been used, fracture occurred soon after its removal. Union was difficult to achieve in cases of congenital pseudarthrosis of the tibia. Appropriate alignment of the fibular graft is an important factor in preventing stress fracture. The vascularised fibula should be protected during the first year after union.

Postoperative complications at the donor site included transient palsy of the superficial peroneal nerve in three patients, contracture of flexor hallucis longus in two and valgus deformity of the ankle in three.

Vascularised fibular grafts are useful in the reconstruction of massive bony defects. We believe that meticulous preoperative planning, including choosing which vessels to select in the recipient and the type of fixation devices to use, and care in the introduction of the vascularised fibula, can improve the results and prevent complications.

Force distribution through the wrist joint in patients with different stages of Kienböck's disease: using computed tomography osteoabsorptiometry

The pattern of subchondral bone density has been considered to reflect the stress distribution that occurs under physiologic loading conditions. To determine the force distribution through the wrist joint with Kienböck's disease in living subjects, we applied a computed tomography osteoabsorptiometry and investigated the subchondral bone density pattern across the radio-carpal joint of 6 normal subjects and 10 patients suffering from Kienböck's disease (Lichtman's stage IIIA, 5 patients; stage IIIB, 5 patients). A single density maximum was found in each scaphoid and lunate fossa in all normal subjects. Among the subjects with Kienböck's disease, the current analysis demonstrated that the density maximum area significantly increased in the scaphoid fossa and decreased in the lunate fossa from stage IIIA to IIIB group. These findings indicate that the load is shifted away from the lunate to the scaphoid with the progression of Kienböck's disease in living subjects.

Vascularised fibular grafts. An experience of 102 patients

The results and complications of 104 vascularised fibular grafts in 102 patients are presented. Bony union was ultimately achieved in 97 patients, with primary union in 84 (84%). The mean time to union was 15.5 weeks (8 to 40). In 13 patients, primary union was achieved at one end of the fibula and secondary union at the other end. In these patients, the mean time to union was 31.1 weeks (24 to 40). Five patients failed to achieve union, with a resultant pseudarthrosis (3 patients) or amputation (2 patients). There were various complications. Immediate thrombosis occurred in 14 cases. In two of 23 patients with osteomyelitis, infection recurred at two and six months after surgery, respectively. Both patients had active osteomyelitis less than one month before the operation. Bony infection occurred in a patient with a synovial sarcoma of the forearm one year after surgery. In 15 patients, 19 fractures of the fibular graft occurred after bony union, all except one within one year after union. In patients in whom an external fixator had been used, fracture occurred soon after its removal. Union was difficult to achieve in cases of congenital pseudarthrosis of the tibia. Appropriate alignment of the fibular graft is an important factor in preventing stress fracture. The vascularised fibula should be protected during the first year after union. Postoperative complications at the donor site included transient palsy of the superficial peroneal nerve in three patients, contracture of flexor hallucis longus in two and valgus deformity of the ankle in three. Vascularised fibular grafts are useful in the reconstruction of massive bony defects. We believe that meticulous preoperative planning, including choosing which vessels to select in the recipient and the type of fixation devices to use, and care in the introduction of the vascularised fibula, can improve the results and prevent complications.

Spontaneous intracranial hypotension associated with bilateral chronic subdural hematomas--case report

A 34-year-old female presented with spontaneous intracranial hypotension (SIH) manifesting as severe postural headache and meningism. Magnetic resonance (MR) imaging with gadolinium showed diffuse pachymeningeal enhancement. She developed bilateral chronic subdural hematomas 4 weeks after the onset of the symptoms. MR imaging showed descent of the midline structures of the brain. The bilateral chronic subdural hematomas were surgically drained, with no remarkable pressure. Postoperative MR imaging showed complete resolution of the pachymeningeal enhancement and relevation of the midline structures of the brain. SIH is an uncommon and probably unrecognized condition because of the usually benign course. However, this case emphasizes that SIH is not entirely benign. SIH should be considered if there is no identifiable risk for intracranial hemorrhage, particularly in young patients. Neurosurgical intervention for the treatment of the underlying cerebrospinal fluid leak may be required if SIH persists.

Reduction and fixation of sacroiliac joint dislocation by the combined use of S1 pedicle screws and the galveston technique

STUDY DESIGN

This retrospective study was designed to analyze the results of the treatment with S1 pedicle screws and the Galveston technique of seven patients with sacroiliac dislocation.

OBJECTIVES

To evaluate the effectiveness of the combined use of S1 pedicle screws and the Galveston technique for the treatment of sacroiliac dislocation.

SUMMARY OF BACKGROUND DATA

Although several procedures for internal fixation of sacroiliac dislocation have been reported, there have been no reports discussing surgical treatment of sacroiliac dislocation by the combined use of S1 pedicle screws and the Galveston technique.

METHODS

Seven patients with sacroiliac dislocation were treated with pedicle screws of S1 and iliac rod according to the Galveston technique. In the seven patients, the dislocation was associated with vertical displacement of the sacroiliac joint and rotational deformity of the pelvic ring. They were classified into Type-C pelvic disruption according to the Tile's classification. Three patients with disruption of the symphysis pubis underwent additional fixation of the symphysis using a dynamic compression plate. The remaining four patients were treated by the posterior procedure alone.

RESULTS

The vertical displacement was completely reduced in five patients, and the rotational deformity was completely corrected in four patients. The reduction was maintained at the time of the final follow-up evaluation. There were no perioperative complications with the exception of late infection in one patient.

CONCLUSIONS

The combined use of S1 pedicle screws and the Galveston technique provided immediate stability and sufficient reduction for sacroiliac dislocation in seven patients in this study. This hybrid internal fixation procedure is useful for reduction and fixation of sacroiliac dislocation associated with the vertical and rotational instability of the pelvic ring.

Cineradiographic motion analysis of normal lumbar spine during forward and backward flexion

STUDY DESIGN

Motion characteristics of the lumbar spine in the sagittal plane were investigated in vivo using cineradiography.

OBJECTIVES

To evaluate the differences in motion characteristics of the normal lumbar spine between forward and backward flexion.

SUMMARY OF BACKGROUND DATA

Despite previous lumbar kinematic studies, differences in motion characteristics of the lumbar spine between forward and backward flexion remain unclear.

METHODS

Cineradiographic motion analysis was performed in 10 asymptomatic healthy male volunteers for two different lumbar motions. The motions consisted of active forward flexion (from maximum extension to maximum flexion) and active backward flexion (from maximum flexion to maximum extension). Displacements of the anterior and posterior vertebral corners from L3/L4 to L5/S1 were measured continuously in reference to the local coordinate system. Parameters investigated were onset of segmental motion, velocity of segmental motion, and continuous motion profiles of the vertebral corners during the two different motions.

RESULTS

During forward flexion, initial lumbar motion started stepwise from the upper level (L3/L4) to the lower levels with phase lags. Angular velocity at the onset of motion increased as the level descended. On the contrary, during backward flexion, initial motion started from the lower level (L5/S1) to the upper levels. There was no relation between velocity and spinal levels during backward flexion. Motion profiles of both anterior and posterior vertebral corners at L3/L4 and L4/L5 segments during forward flexion were similar to those during backward flexion. However, the motion profiles at L5/S1 segment during forward flexion were different from those during backward flexion.

CONCLUSIONS

During forward flexion of the lumbar spine, initial motion started from upper segments to the lower segments with phase lags. During backward flexion, initial motion started from the lower segments to the upper segments. Motion profiles of the vertebral corners during forward flexion were similar to those during backward flexion at L3/L4 and L4/L5. The motion profiles at L5/S1 were different between both flexions.

Abasic site recognition mechanism by the Escherichia coli exonuclease III

In order to elucidate the mechanism of AP site recognition by Echerichia coli exonuclease III (exoIII), site-directed mutagenesis of the Tyr109, the Trp212, and the Phe213 residues, which were conserved in the type II AP endonuclease from various organisms and located in the vicinity of the catalytic site, was performed. The exoIII-W212S mutant lacked any detectable AP endonuclease activity and binding ability to the duplex DNA containing an AP site, while the exoIII-Y109S and exoIII-F213W mutants retained a low level of activities (13% and 83%, respectively, compared with wild-type exoIII). This study suggests that the Trp212 is an important component for abasic site recognition by the E. coli exonuclease III.

Postoperative subcoracoid impingement syndrome in patients with rotator cuff tear

Impingement of the tendinous rotator cuff on the coracoid process (subcoracoid impingement syndrome) has rarely been reported as a cause of pain after surgery for rotator cuff tear. We evaluated clinical features, surgical results, and histopathology findings of resected coracoid processes in patients with subcoracoid impingement syndrome after anterior acromioplasty and management of rotator cuff tear. Pain at the anterior aspect of the shoulder, localized tenderness of the coracoid process, anterior shoulder pain on horizontal adduction testing, and positive subcoracoid block suggest subcoracoid impingement syndrome. Postoperative subcoracoid impingement syndrome was investigated in 11 of 216 cases with rotator cuff surgery. The average patient age at the time of surgery was 61.2 y (range, 28-78 y). Coracoplasty (partial resection of the posterolateral side of the coracoid process) was performed in 9 shoulders that had not responded to a 6-month regimen of conservative treatment. Complete pain relief was achieved in all cases. Histopathologic findings revealed hypertrophic changes of the fibrocartilage layer at the posterior aspect of the resected coracoid process. We concluded that subcoracoid impingement syndrome was an important factor in unsuccessful rotator cuff surgery and recommend that coracoplasty be performed on patients with symptoms of subcoracoid impingement syndrome after management of the rotator cuff tear.

The biomechanical effect of postoperative hypolordosis in instrumented lumbar fusion on instrumented and adjacent spinal segments

STUDY DESIGN

Change in lumbar lordosis was measured in patients that had undergone posterolateral lumbar fusions using transpedicular instrumentation. The biomechanical effects of postoperative lumbar malalignment were measured in cadaveric specimens.

OBJECTIVES

To determine the extent of postoperative lumbar sagittal malalignment caused by an intraoperative kneeling position with 90 degrees of hip and knee flexion, and to assess its effect on the mechanical loading of the instrumented and adjacent segments.

SUMMARY OF BACKGROUND DATA

The importance of maintaining the baseline lumbar lordosis after surgery has been stressed in the literature. However, there are few objective data to evaluate whether postoperative hypolordosis in the instrumented segments can increase the likelihood of junctional breakdown.

METHODS

Segmental lordosis was measured on preoperative standing, intraoperative prone, and postoperative standing radiographs. In human cadaveric spines, a lordosis loss of up to 8 degrees was created across L4-S1 using calibrated transpedicular devices. Specimens were tested in extension and under axial loading in the upright posture.

RESULTS

In patients who underwent L4-S1 fusions, the lordosis within the fusion decreased by 10 degrees intraoperatively and after surgery. Postoperative lordosis in the proximal (L2-L3 and L3-L4) segments increased by 2 degrees each, as compared with the preoperative measures. Hypolordosis in the instrumented segments increased the load across the posterior transpedicular devices, the posterior shear force, and the lamina strain at the adjacent level.

CONCLUSIONS

Hypolordosis in the instrumented segments caused increased loading of the posterior column of the adjacent segments. These biomechanical effects may explain the degenerative changes at the junctional level that have been observed as long-term consequences of lumbar fusion.

Accumulation of photosensitizer ATX-S10 (Na) in experimental corneal neovascularization

PURPOSE

To determine the most appropriate time for laser irradiation to produce selective occlusion of new corneal vessels by photodynamic therapy (PDT) with a new photosensitizer, ATX-S10(Na).

METHODS

The time course of the plasma levels of ATX-S10(Na) and the degree of dye accumulation in the corneal neovascularization after intravenous administration was determined in rabbit eyes. Plasma concentration of ATX-S10(Na) was analyzed by a spectrophotometer. The amount of ATX-S10(Na) in the new corneal vessels was measured by nitrogen-pulsed laser spectrofluorometry. Frozen sections of neovascularized cornea and iris were observed by fluorescence microscopy.

RESULTS

Plasma ATX-S10(Na) concentration was highest 5 minutes after dye injection and rapidly decreased and reached almost zero at 24 hours, indicating its prompt excretion from the body. The amount of ATX-S10(Na) in the new corneal vessels as measured by nitrogen-pulsed laser spectrofluorometry increased and reached maximal level at 2 to 4 hours. Under fluorescence microscopy, the dye was more abundantly localized in the wall of new corneal vessels than in the normal tissue at 2 to 4 hours.

CONCLUSION

These results indicate that laser irradiation between 2 and 4 hours after dye injection is appropriate for selective PDT with ATX-S10(Na) for the occlusion of new corneal vessels.

Selective occlusion of choroidal neovascularization by photodynamic therapy with a water-soluble photosensitizer, ATX-S10

BACKGROUND AND OBJECTIVE

To determine the optimal treatment parameters for selective occlusion of choroidal neovascularization (CNV) by photodynamic therapy (PDT) by using the photosensitizer ATX-S10 and a diode laser (wavelength = 670 nm).

MATERIALS AND METHODS

Experimental CNV was induced in rat fundi by argon laser photocoagulation. The distribution of ATX-S10 in the chorioretina was analyzed by fluorescence microscopy, and the optimal treatment parameters for selective occlusion of CNV were investigated by changing the dosage and timing of laser irradiation. CNV closure and resulting damage of the surrounding tissue were documented by fluorescein angiography and light and electron microscopies.

RESULTS

Fluorescence of ATX-S10 was observed to be localized in the vascular lumen of the retina and choroid within 5 min after dye injection and increased in intensity in CNV up to 2-6 h and decreased rapidly in normal tissue. Laser irradiation with radiant exposures of 7.4 J/cm2 applied immediately after dye injection or with 22.0 J/cm2 at 2-4 h later effectively occluded the induced CNV without causing significant damage to normal retinal capillaries and large choroidal vessels.

CONCLUSIONS

PDT using ATX-S10 can selectively occlude CNV. ATX-S10 is a potentially useful photosensitizer for the treatment of CNV.

Uptake and elimination of sevoflurane in rabbit tissues--an in vivo magnetic resonance spectroscopy study

PURPOSE

Previous pharmacokinetic studies of fluorinated anesthetics using 19F-magnetic resonance spectroscopy (19F-MRS) have focused on the brain. Investigation of other tissues would give more precise information about the pharmacokinetics of inhalational anesthetics. In this study we investigated the pharmacokinetics of uptake and elimination of sevoflurane in brain, liver, muscle, venous blood and arterial blood of rabbits.

METHODS

Twenty rabbits were examined by 19F-MRS conducted at 4.7 Tesla using a 1-cm-diameter surface coil for brain (n = 4), liver (n = 5) and muscle (n = 5), and a 1.3-cm-diameter surface coil for arterial (n = 3) and venous (n = 3) blood. Sevoflurane, 4% in oxygen, was administered for 120 min, followed by 120 min elimination.

RESULTS

Both the uptake and elimination kinetics were best fitted by a biexponential curve which was divided into fast and slow components. During the uptake experiment the time required to reach half of the maximum spectroscopic intensity in each tissue was 1.6 min in arterial blood, 4.7 min in liver, 12.2 min in venous blood, 14.4 min in brain and 20.9 min in muscle. During the elimination experiment the time required to reach half maximum intensity was 2.4 min in arterial blood, 6.3 min in liver, 13.4 min in venous blood, 19.6 min in brain and 28.7 min in muscle.

CONCLUSIONS

Sevoflurane uptake or elimination in the tissues examined followed biexponential kinetics. In this rabbit model, sevoflurane uptake and elimination were fastest in arterial blood, followed, in order, by liver, venous blood, brain and muscle.

An epidemiologic study of occupational low back pain in truck drivers

The factors in volved in occupational low back pain occurring in professional drivers were investigated epidemiologically with questionnaires (92 items) including low back symptoms, personal factors and occupational factors. The responses of one hundred fifty-three of one hundred eighty-one truck drivers who work in a large chemical industry corporation were analyzed after they had completely filled in questionnaires. As analysis of the results shows, the prevalence of LBP in one month of the survey was 50.3%. Correlating among data of personal factors and LBP, the prevalence of LBP was significantly higher in the drivers (Odd's ratio of 2.7) who answered "yes" to the item "shortage of spending time with family than in the drivers who didnt answer "yes. The occupational factors, working load and working environment showed no correlation with the prevalence of LBP. In contrast, 3 items of the working format related significantly to the prevalence of LBP: "irregular duty time (Odd's ratio of 3.0), "short resting time (2.4), and "long driving time in a day (2.0). Eighty-one of the 153 drivers (52.9%) pointed out the relationship between LBP and work, especially work which muolves vibration or road shock. Our results and the results from previous published studies suggested that vibration is an obvious risk factor for LBP. From the viewpoint of prophylaxis, an improvement in working conditions reduces the incidence of drivers' LBP to some extent.

Decreased plasma levels of fibronectin in amyotrophic lateral sclerosis

OBJECTIVES

Fibronectin (FN) possesses a wide range of biological functions. However, the role of plasma FN in vivo has not yet been established and there have been no published studies of plasma FN in ALS. The aim of this study was to measure plasma FN in ALS patients.

MATERIAL AND METHODS

We measured plasma FN levels in 28 ALS patients, 18 control subjects with other neurologic or muscular diseases (control group A) and 21 healthy adults (control group B). The age and sex distributions among the 3 groups were comparable.

RESULTS

Plasma FN levels were significantly lower in ALS patients than in control groups A and B. There was also a significant negative correlation between plasma FN levels and duration of illness in ALS patients.

CONCLUSION

These data suggest that a metabolic alteration of FN may take place in ALS and that the measurement of plasma FN may serve as an indicator of clinical progression of this disorder.

Selective photodynamic effects of the new photosensitizer ATX-S10(Na) on choroidal neovascularization in monkeys

OBJECTIVE

To determine the optimal treatment variables for photodynamic therapy (PDT) with new photosensitizer ATX-S10(Na) (13,17-bis[1-carboxypropionyl] carbamoylethyl-8-etheny-2-hydroxy-3-hydroxyiminoethyliden e-2,7,12,18-tetranethyl 6 porphyrin sodium) to induce selective occlusion of choroidal neovascularization (CNV) in nonhuman primate eyes.

METHODS

Experimental CNV was induced in monkey eyes by laser photocoagulation, and PDT was performed in neovascularized and healthy eyes with different treatment variables. At 0 to 150 minutes after 4-, 8-, and 12-mg/kg of body weight intravenous injections of ATX-S10(Na), a diode laser was irradiated at the dose of 1 to 127 J/cm2 (wavelength, 670 nm). Vascular occlusion induced by PDT was evaluated using fluorescein angiography, indocyanine green angiography, and histological examination at 1 day to 4 weeks after irradiation.

RESULTS

Selective occlusion of CNV without damage to healthy retinal and choroidal capillaries was achieved in the following conditions: 30 to 74 J/cm2 irradiation at 30 to 74 minutes after the 8-mg/kg injection, and 1 to 29 J/cm2 irradiation at 30 to 74 minutes or 30 to 74 J/cm2 irradiation at 75 to 150 minutes after the 12-mg/kg dye injection. Regrowth of CNV often occurred when the retina was heavily injured by excessive PDT.

CONCLUSION

By using optimal treatment variables, PDT using ATX-S10(Na) induces selective occlusion of CNV in nonhuman primate eyes, providing the possibility of therapeutic application to the clinical practice.

CLINICAL RELEVANCE

Occlusion of CNV without direct damage to the sensory retina is useful to preserve visual acuity in patients with exudative age-related macular degeneration. A clinical trial of PDT using ATX-S10(Na) is desirable.

Bipolar hemiarthroplasty for osteonecrosis of the femoral head. A 7- to 18-year followup

This study evaluated clinical and radiographic results of bipolar hemiarthroplasties for the treatment of osteonecrosis of the femoral head. Forty-eight hips in 35 patients with a mean age of 37 years who underwent primary bipolar hemiarthroplasties were observed for an average of 11.4 years. Osteonecrosis was associated with corticosteroid use (21 patients), alcohol (six patients), idiopathic (four patients), and other conditions (four patients). The average Harris hip score was 46 before surgery and 86 at the time of the final followup. Twenty (42%) hips were radiographic failures, and 12 (25%) hips were revised. Groin symptoms were present in 20 (42%) hips. Radiographic proximal migration greater than 4 mm and osteoarthritic signs of the acetabulum indicated a high risk of groin symptoms. The results were inferior to those previously reported for total hip arthroplasty. Thus, for the treatment of osteonecrosis of the femoral head in which necrotic lesions are wide, the authors no longer use this system and currently use total hip arthroplasty.

Phenotypical and morphological analyses of intraepithelial and lamina propria lymphocytes in normal and regenerating gastric mucosa of rats in comparison with those in intestinal mucosa

While the intestine has abundant intraepithelial lymphocytes (IELs) including extrathymically differentiated T-cell populations and natural killer (NK) cells, the stomach contains only a few IELs. To elucidate whether the gastric epithelium is capable of inducing predominant lymphocyte lodging and subsequent differentiation within, we counted the number of IELs and lamina propria lymphocytes (LPLs) and calculated the percentage of IELs to total lymphocytes for each alpha-beta T cell, gamma-delta T cell, CD4+ cell, CD8+ cell and NK cell in normal and regenerating gastric mucosa as well as the intestinal mucosa of the rat. In the normal rat pylorus, a few alpha-beta T cells but no gamma-delta T cells were found in the epithelium and lamina propria. In regenerating gastric mucosa, all subsets of LPLs increased in number to a degree comparable to those in intestinal mucosa, whereas every IEL subset, though slightly increased, was much smaller in number than in the intestinal mucosa, consequently giving lower percentages of IELs. Electron microscopic observations revealed that all IELs in regenerating gastric mucosa were agranular, while 55% of intestinal IELs were large granular lymphocytes positively stained for an NK-cell, alpha-beta-cell or gamma-delta T-cell marker. The present results indicate that, unlike the intestinal epithelium, the gastric epithelium does not induce the preferential localization of T cells/NK cells and T-cell differentiation into granular lymphocytes in the epithelium even under conditions of prominent LPL infiltration.

Expression of vascular endothelial growth factor by granulated metrial gland cells in pregnant murine uteri

Granulated metrial gland (GMG) cells are a characteristic uterine component belonging to a natural killer cell lineage. This study is aimed at revealing their kinetic and spatial relationship with vascular growth during pregnancy and the expression of vascular endothelial growth factor (VEGF). GMG cells and blood vessels were identified by periodic-acid-Schiff-reagent (PAS)-stained granules and positive staining for factor-VIII-related antigen, respectively. GMG cells were widely distributed in the decidua and metrial gland and showed a numerical increase with a peak at day 13 in parallel with the increase of vascular density. Preceding the maximal vascular development at day 13, microvessels with a narrow lumen representative of neovascularization prevailed at days 7-9, and the VEGF content in the decidua/metrial gland was significantly elevated at days 7-13 concurrently with mRNA expression. By immunolight microscopy combined with PAS staining, GMG cells with PAS-stained granules were positive for VEGF. Immunoelectron microscopy demonstrated that immunoreactions were diffuse in the cytoplasm but not localized in the granules. In contrast, fibroblast-like stromal cells were negative. These data indicate that GMG cells express VEGF and may play inducing roles in uterine neovascularization during pregnancy.

Purification and some properties of an aminopeptidase from the seeds of Cannabis sativa

An aminopeptidase (HSA) with a molecular mass of 78 kDa was purified from hemp (Cannabis sativa) seeds. The activity was inhibited by monoiodeacetic acid, p-chloromercuri-phenylsulfonic acid, and Zn2+ ion. The specificity of HSA was similar to that of a leucyl aminopeptidase [EC 3.4.11.1] from mammalian cytosol. However, other enzyme properties were different from these of leucyl aminopeptidase.

Complications of pedicle screw fixation in reconstructive surgery of the cervical spine

STUDY DESIGN

Retrospective evaluation of complications in 180 consecutive patients with cervical disorders who had been treated by using pedicle screw fixation systems.

OBJECTIVES

To determine the risks associated with pedicle screw fixation in the cervical spine and to emphasize the importance of preoperative planning and surgical techniques in reducing the risks of this procedure.

SUMMARY OF BACKGROUND DATA

Generally, pedicle screw fixation in the cervical spine has been considered too risky for the neurovascular structures. There have been several reports describing the complications of lateral mass screw-plate fixation. However, no studies have examined in detail the complications associated with cervical pedicle screw fixation.

METHODS

One hundred eighty patients who underwent cervical reconstructive surgery using cervical pedicle screw fixation were reviewed to clarify the complications associated with the pedicle screw fixation procedure. Cervical disorders were spinal injuries in 70 patients and nontraumatic lesions in 110 patients. Seven hundred twelve screws were inserted into the cervical pedicles, and the locations of 669 screws were radiologically evaluated.

RESULTS

Injury of the vertebral artery occurred in one patient. The bleeding was stopped by bone wax, and no neurologic complication developed after surgery. On computed tomographic (CT) scan, 45 screws (6.7%) were found to penetrate the pedicle, and 2 of 45 screws caused radiculopathy. Besides these three neurovascular complications directly attributed to screw insertion, radiculopathy caused by iatrogenic foraminal stenosis from excessive reduction of the translational deformity was observed in one patient.

CONCLUSIONS

The incidence of the clinically significant complications caused by pedicle screw insertion was low. Complications associated with cervical pedicle screw fixation can be minimized by sufficient preoperative imaging studies of the pedicles and strict control of screw insertion. Pedicle screw fixation is a useful procedure for reconstruction of the cervical spine in various kinds of disorders and can be performed safely.

Reduction of polyethylene wear by concave dimples on the frictional surface in artificial hip joints

For the purpose of reduction of polyethylene wear generated in artificial hip joints, concave dimples were formed on the surface of the metal femoral head by electrical discharge etching with the constant diameter of 0.5 mm, pitch of 1.2 mm, and depth of 0.1 mm. Using a hip joint simulator, the total amount of polyethylene wear was 7.2 mg in the concave-patterned condition and 23.1 mg in the nonpatterned condition. The reasons for the reduction of polyethylene wear by the concave pattern may be i) a reduction of abrasive wear by providing escape dimples for wear particles and ii) an improvement in the lubricity on the frictional surface by the supply of lubricant that is stored in dimples.

Structure of lamina propria lymphoid follicles and associated epithelium in the gastric mucosa during Helicobacter pylori infection in ulcer-bearing Mongolian gerbils

To develop a gerbil model of Helicobacter pylori-induced chronic active gastritis comparable in severity to human lesions, we made acetic acid-induced ulcer in the anterior antral wall and concurrently challenged 1 x 10(8) colony-forming units bacteria per os. At 30 and 60 days after inoculation, the number of viable bacteria colonizing on the surface epithelium of the gastric mucosa was larger in ulcer-bearing animals compared to non-bearing ones. Furthermore, in the former animals, neutrophil and mononuclear cell infiltration as well as lymphoid follicle formation in the lamina propria was more prominent. Electron microscopically, lymphoid follicle-associated epithelium displayed specialized structures. Namely, brush cells interposed between mucous epithelial cells and characterized by prominent microfilament bundles and many apical vesicles or caveola specifically embraced the cluster of intraepithelially invading lymphocytes and macrophage-like cells by the attenuated cytoplasm in an analogous manner to M cells in Peyer's patches. The present study has demonstrated that ulcer formation enhances both H. pylori colonization and lamina propria lymphoid follicle formation and suggested that follicle-associated epithelium might play roles in the delivery of intraluminal antigen.

Trehalose 6,6'-dimycolate (Cord factor) enhances neovascularization through vascular endothelial growth factor production by neutrophils and macrophages

Trehalose 6,6'-dimycolate (TDM) plays important roles in the development of granulomatous inflammation during infection with Mycobacterium spp., Rhodococcus spp., etc. To reveal the augmenting effect of TDM on vascular endothelial growth factor (VEGF) production and neovascularization, we investigated murine granulomatous tissue air pouches induced by Rhodococcus sp. strain 4306 TDM dissolved in Freund's incomplete adjuvant (FIA), comparing them to pouches treated with FIA alone. Histologically, granulomatous tissue and new vessel formation, which reached a maximum at day 7, was greatly enhanced by treatment with TDM. At day 1, VEGF-positive neutrophils accumulated in the pouch wall with frequency of 95% of total infiltrating cells, adhering to TDM-containing micelles. By day 3, granulomatous tissue and new vessels started to develop, and VEGF-positive macrophages appeared in a small number and gradually increased in number thereafter. The pouch contents of VEGF, interleukin-1beta, tumor necrosis factor alpha, and transforming growth factor beta were significantly elevated in TDM-treated pouches, with peaks at days 1, 0.5, 1, and 3, respectively, compared to those of control pouches, while that of basic fibroblast growth factor showed no significant increase. Treatment with anti-VEGF antibody inhibited TDM-induced granulomatous tissue formation and neovascularization, and administration of recombinant VEGF into pouches treated with FIA alone induced neovascularization comparable to that in the TDM-treated pouches. Incubation of neutrophils and macrophages on TDM-coated plastic dishes increased the VEGF release. The present results indicate that TDM augments VEGF production by neutrophils and macrophages and induces neovascularization in the granulomatous tissue.

Interference screw fixation of doubled flexor tendon graft in anterior cruciate ligament reconstruction - biomechanical evaluation with cyclic elongation

OBJECTIVE

To biomechanically evaluate interference screw fixation of the doubled flexor tendon graft in anterior cruciate ligament reconstruction using cyclic elongation.

DESIGN

Biomechanical properties of the interference screw fixation of the flexor tendons were compared with those of three standard fixation techniques which had been commonly performed in anterior cruciate ligament reconstruction.

BACKGROUND

The interference screw fixation of the flexor tendon graft has attracted notice because of various possible advantages.

METHODS

Forty fresh frozen porcine hind limbs were divided into four groups of ten knees each. Anterior cruciate ligament reconstruction was carried out in each group using one of four different procedures. For each group, five femur-graft-tibia complexes underwent submaximal cyclic elongation of 5000 cycles after initial tension of 80 N was applied. Then, tensile testing was performed in the same manner for the complex with a tensile tester. The remaining five complexes were examined in the same tensile test without applying any cyclic elongation.

RESULTS

The initial tension was more rapidly relaxed by cyclic elongation in the flexor tendon graft fixed with interference screws than in the bone-patellar tendon-bone graft fixed with two standard techniques. After cyclic elongation, while the ultimate failure load of the former was significantly lower than the latter, the linear stiffness of the former was significantly higher than the flexor tendon graft fixed with sutures.

CONCLUSION

The present study has clarified that the advantage of the interference fixation for the doubled flexor tendon graft is the high linear stiffness of the FGT complex, and the disadvantage of this screw is the low ultimate failure load of the FGT complex.

RELEVANCE

The present study has suggested that vigorous activities should not be permitted for the patients in the early period after anterior cruciate ligament reconstruction using this fixation technique, because of its low ultimate failure load.

Long-term effectiveness of photodynamic therapy by using a hydrophilic photosensitizer ATX-S10(Na) against experimental choroidal neovascularization in rats

BACKGROUND AND OBJECTIVE

We previously demonstrated that a hydrophilic photosensitizer ATX-S10 had a potent photodynamic effect. This study was designed to reveal the long-term effectiveness of photodynamic therapy (PDT) with this agent in occluding choroidal neovascularization (CNV) and its selectivity in the neovascular tissue.

STUDY DESIGN/MATERIALS AND METHODS

Experimental CNV was induced by intense photocoagulation in rat eyes. Immediately or 2 hours after intravenous injection of 8 mg/kg body weight of ATX-S10(Na), a cis isomer of ATX-S10, eyes were irradiated by a diode laser at the radiance of 3.25-65.3 J/cm(2) Vascular occlusion was identified by fundus photography, fluorescein angiography, and histology at 1, 3, 7, 14, and 28 days after PDT. As controls, non-neovascular eyes were subjected to PDT and similarly analyzed.

RESULTS

By using the following treatment parameters, PDT with ATX-S10(Na) successfully occluded CNV without causing occlusion of retinal capillaries for 28 days; 7.4 and 19.6 J/cm(2) immediately after dye injection and 36.7 and 65.3 J/cm(2) 2 hours after injection. Although these conditions also caused occlusion of normal choriocapillaries and mild injuries of retinal vessels, retinal pigment epithelium, and photoreceptors at 1 day, retinal vessels and pigment epithelial cells recovered from damages by 28 days. No injuries were found in the inner retina.

CONCLUSION

In optimal treatment conditions, PDT with ATX-S10(Na) can induce long-term, selective occlusion of CNV without causing irreversible damages in the inner retina.

Experimental study of vascularized bone grafts: hypertrophy of the grafted bone

The mechanism underlying hypertrophy of experimentally vascularized bone grafts was studied in 15-week-old rats. The segmental ulna was grafted to the tibial defect with an external fixator. In experiment 1, 24 rats were classified into four groups to evaluate conventional (non-vascularized), cuff (periosteum-encased, non-vascularized), and vascularized bone grafts, and vascularized segmental grafts with fracture. In experiment 2, 12 rats were classified into two groups according to the presence of mechanical loading. This involved vascularized bone grafts with external fixators, and vascularized bone grafts with external fixators removed after bone union. The bone dynamics of the grafts were investigated by several methods, including roentgenographic analysis, histologic studies, and fluorochrome labeling. In experiment 1, a slight bone formation was recognized in the conventional bone graft, while irregular bone formation with creeping substitution was observed in the cuff graft. The vascularized bone graft showed significant hypertrophy; hypertrophy of the vascularized bone with fracture was greater than that without fracture. In experiment 2, markedly circumferential bone formation was observed after removal of the external fixator, while slight new bone formation was observed during the late postoperative period in bone with an external fixator. These results suggest that hypertrophy can be promoted by artificial fracture of the grafted bone, and that mechanical loading is an important factor for remodeling of grafted bone.

Liver microvascular architecture: an insight into the pathophysiology of portal hypertension

Structural adaptations in the liver to constantly receive and release a large volume of circulating blood at low pressure are present at many levels; alteration of these structures can modify flow and perturb pressure gradients. Liver growth multiplies the lobule number by a factor of 4-5 after birth. Lobule configuration conforms with observations in space division, each unit being bordered by planes; curvature will impede expansibility and retractability among units. Lobular organization with hepatocytic plates and sinusoids, being radial centrally and reticular peripherally, maximizes its reversible distensibility. Resistance sites in the portal, sinusoidal, and hepatic system are subject to species variations; real portal sphincters are photographed in the frog. Small venules are demonstrably resistive. In endothelin-1-induced rat portal hypertension, the distal segment of preterminal portal venules constricts most intensely, whereas the terminal portal venules and sinusoids are flaccid. Their pericytes and arachnocytes (stellate cells, Ito cells, retinol-storing cells), respectively, possess no effective contractile machinery. In the dog, the initial sublobular veins react with venoconstriction to many stimulations. Well-developed musculature in hepatic veins, as in man and pig, can regulate flow by junctional constriction. These histoarchitectonics provide hepatic hemodynamics with high capacitance and high compliance properties. The hepatic artery supplies oxygenated blood to five stromal compartments: peribiliary vascular plexus, portal tract interstitium, portal vein vasa vasorum, hepatic capsule, and central-sublobular-hepatic vein vasa vasorum. Its role as the nutrient vessel to the veins is established, but what influence it may have in the pathophysiology of portal hypertension awaits clarification.

Growth factor-induced expression of macrophage migration inhibitory factor in osteoblasts: relevance to the plasminogen activator system

Macrophage migration inhibitory factor (MIF) is a cytokine that mediates inflammatory processes in a variety of tissues. In this study, we examined the expression of MIF mRNA in the mouse osteoblastic cell line MC3T3-E1, whose proliferation is promoted by various growth factors. In the subconfluent state, transforming growth factor-beta, basic fibroblast growth factor, insulin-like growth factor-II, and fetal calf serum markedly upregulated MIF mRNA expression. The upregulation of MIF mRNA was less extensive when the cells were stimulated by the same growth factors in the overconfluent state. We also investigated the expression of MIF mRNA through a whole cell cycle from G0 phase when the osteoblastic cells were synchronized by serum starvation. The MIF mRNA expression, which gradually increased from the G0 and reached its maximum at the S phase, was nonperiodic. Moreover, human recombinant MIF upregulated the expression of urokinase plasminogen activator inhibitor-1 (PAI-1) precursor mRNA in human osteoblastic Saos-2 cells. Plasminogen activator (PA) is known to play an important role in bone metabolism, for example, in activation of procollagenase or growth factors indirectly via the formation of plasmin, and in mitogenic activity for osteoblastic cells. Our results suggest that MIF modulates the proliferation of osteoblasts and, moreover, bone tissue remodeling through the PA and plasmin system.

Macrophage migration inhibitory factor up-regulates expression of matrix metalloproteinases in synovial fibroblasts of rheumatoid arthritis

Neutral matrix metalloproteinases (MMPs) are responsible for the pathological features of rheumatoid arthritis (RA) such as degradation of cartilage. We herein show the up-regulation of MMP-1 (interstitial collagenase) and MMP-3 (stromelysin) mRNAs of cultured synovial fibroblasts retrieved from rheumatoid arthritis (RA) patients in response to macrophage migration inhibitory factor (MIF). The elevation of MMP-1 and MMP-3 mRNA was dose-dependent and started at 6 h post-stimulation by MIF, reached the maximum level at 24 h, and was sustained at least up to 36 h. Interleukin (IL)-1beta mRNA was also up-regulated by MIF. These events were preceded by up-regulation of c-jun and c-fos mRNA. Tissue inhibitor of metalloproteinase (TIMP)-1, a common inhibitor of these proteases, was slightly up-regulated by MIF. Similarly, mRNA up-regulation of MMP-1 and MMP-3 was observed in the synovial fibroblasts of patients with osteoarthritis. However, their expression levels were much lower than those of RA synovial fibroblasts. The mRNA up-regulation by MIF was inhibited by the tyrosine kinase inhibitors genestein and herbimycin A, as well as the protein kinase C inhibitors staurosporine and H-7. On the other hand, the inhibition was not seen after the addition of the cyclic AMP-dependent kinase inhibitor, H-8. The mRNA up-regulation of MMPs was also inhibited by curcumin, an inhibitor of transcription factor AP-1, whereas interleukin-1 receptor antagonist, an IL-1 receptor antagonist, failed to inhibit the mRNA up-regulation. Considering these results, it is suggested that 1) MIF plays an important role in the tissue destruction of rheumatoid joints via induction of the proteinases, and 2) MIF up-regulates MMP-1 and MMP-3 via tyrosine kinase-, protein kinase C-, and AP-1- dependent pathways, bypassing IL-1beta signal transduction.

Indirect posterior reduction and fusion of the traumatic herniated disc by using a cervical pedicle screw system

OBJECT

In this study the authors retrospectively review 16 patients with traumatic disc herniation secondary to middle and lower cervical spine injuries who underwent a single posterior reduction and fusion procedure in which a cervical pedicle screw system was used. The study was undertaken to evaluate whether the procedure effectively reduced the disc herniation and whether it can be safely conducted without performing anterior decompressive surgery.

METHODS

A total of 73 patients with middle and lower cervical spine injuries were identified. In 50 patients, pre- and postoperative magnetic resonance (MR) images were obtained, and disc herniation was defined as the presence of an extruded disc that deformed the thecal sac or nerve roots. Traumatic disc herniation was revealed in 16 patients (32%) who underwent a single posterior reduction/fusion procedure in which a cervical pedicle screw system was used. The average follow-up period was 4.25 years (2-6.25 years). In all patients the average kyphotic deformity was 18 degrees, which was corrected to 0.7 degrees lordosis postoperatively. Anterior translation was reduced from 8 to 0.7 mm. The preoperative disc height ratio of 63% (normal 100%) was improved to 104%. Preoperative MR images revealed traumatic disc herniation in all 16 patients; postsurgery, reduction or reversal of disc herniation was observed in all patients. Thecal sac and/or spinal cord compression had disappeared after indirect decompression was achieved using a posterior procedure. No additional decompressive procedures were required to remove residual herniated disc material. Preoperatively, four patients presented with cervical radiculopathy, 10 with myelopathy (eight incomplete and two complete), and two without neurological symptoms. At final follow up, complete recovery was observed in all four patients with radiculopathy and improvement of at least one Frankel grade was shown in six patients (60%) with myelopathy. There were no cases of neurological deterioration immediately after surgery or during the course of the follow-up period. In all patients solid bone union was demonstrated, and there were no implant-related complications.

CONCLUSIONS

Traumatic disc herniation may occur frequently in association with injury of the cervical spine. The incidence of traumatic disc herniation in our series was 32%. The cervical pedicle screw system allowed three-dimensional reduction of the injured cervical segment and reduction or reversal of a disc herniation. After surgery, compression of the thecal sac and/or spinal cord had disappeared. The cervical pedicle screw system provides effective and safe fixation of the cervical spine injury-related traumatic disc herniation, and the surgery can be performed safely in a single posterior-approach procedure without need of additional anterior decompressive interventions.

Sublobular veins as the main site of lymphocyte adhesion/transmigration and adhesion molecule expression in the porto-sinusoidal-hepatic venous system during concanavalin A-induced hepatitis in mice

Lymphocyte infiltration is a manifest feature of hepatitis. To reveal the main site and mechanism of lymphocyte adhesion/extravasation in the hepatic vasculature during inflammation, we morphometrically and histologically analyzed these events in relation to adhesion molecule expression using a murine model of T-cell mediated hepatitis induced by concanavalin A (Con A). Although lymphocyte adhesion was restricted to the sinusoids in untreated mice, it increased in all the segments of porto-sinusoidal-hepatic venous system 8 hours after Con A injection; the number of adhering lymphocytes per unit vascular circumference was the largest in the sublobular veins, relatively large in the central veins and small hepatic veins, and relatively small in the sinusoids and negligible in the portal veins. At 20 hours, extravascular lymphocytes showed similar distribution to lymphocyte adhesion at 8 hours except in the portal veins, around which they were possibly accumulated by the translocation of extrasinusoidal lymphocytes. E-selectin and vascular cell adhesion molecule-1 (VCAM-1) were transiently expressed at 4 to 6 hours, whereas P-selectin and intercellular adhesion molecule-1 were not changed between 0 and 48 hours. In particular, E-selectin expression coincided with that of lymphocyte adhesion in distribution. Lymphocyte attachment was inhibited by pretreatment with anti-E-selectin monoclonal antibody (MAb) or anti-VCAM-1 MAb, and expression of E-selectin and VCAM-1 was suppressed by pretreatment with anti-tumor necrosis factor-alpha (TNF-alpha) MAb. Electron microscopically, lymphocytes were trapped by endothelial lamellipodia and traversed the endothelium by diapedesis. These results indicate that lymphocyte adhesion/transmigration preferentially takes place in the sublobular veins in association with TNF-alpha-induced endothelial activation, i.e., E-selectin and VCAM-1 expression and lamellipodia formation.

The effect of nonphysiologically high initial tension on the mechanical properties of in situ frozen anterior cruciate ligament in a canine model

An experimental study was performed in 32 adult beagle dogs to clarify the effect of nonphysiologically high initial tension on the mechanical and histologic properties of in situ frozen anterior cruciate ligaments. Both anterior cruciate ligaments in each dog underwent the in situ freeze-thaw treatment. The tibial insertion of the ligament was then made free from the tibia along with a cylindrical bone block. In the right knee, an initial tension of 20 N was applied on the anterior cruciate ligament by translocating the bone block in the distal direction. In the left knee, this bone block was anatomically reduced. Each bone block was firmly fixed with an interference screw. Ten animals were sacrificed at 6 weeks and 10 at 12 weeks. The tensile strength and the tangent modulus in the highly tensioned knee were significantly less than those in the physiologically tensioned knee at 12 weeks. Histologically, cell nuclei appeared to be spindle-shaped in the physiologically tensioned knee, while oval nuclei and focal degenerative changes with a number of vacuoles were occasionally found in the matrix in the highly tensioned knee. This study demonstrated that a nonphysiologically high tension significantly deteriorates the mechanical properties of the in situ frozen anterior cruciate ligament compared with physiologic tension.

ROCK inhibitor Y-27632 attenuates stellate cell contraction and portal pressure increase induced by endothelin-1

By using a selective ROCK inhibitor Y-27632, the role of Rho-ROCK signaling in the function of hepatic stellate cells in culture was studied. Stellate cells maintained the "star-like" configuration of the quiescent stage in the presence of Y-27632, while the expression of smooth muscle alpha-actin and PDGF receptor beta was not affected by the agent. Serum-stimulated migration of the cells was significantly suppressed by Y-27632. The contraction of stellate cells induced by 5 nM endothelin-1 was attenuated by the agent in a dose-dependent manner. Formation of F-actin stress fibers and phosphorylation of myosin light chain was apparently reduced by Y-27632 even under the stimulation with endothelin-1. On the other hand, ex vivo liver perfusion experiment revealed that endothelin-1 (2 nM)-induced increase of portal vein constriction was almost completely inhibited by 20 microM Y-27632 with a concomitant improvement of hepatocyte degeneration. These results suggest that ROCK is one of the key regulators of stellate cell motility and that the clinical application of ROCK inhibitors such as Y-27632 should be considered in the reduction of portal hypertension in liver fibrosis and cirrhosis.

Phenotypical and morphological alterations to rat sinusoidal endothelial cells in arterialized livers after portal branch ligation

The hepatic sinusoids are preferentially supplied with portal venous blood and equipped with fenestrated endothelial cells that are distinct from capillary endothelial cells. We previously observed in rats that sinusoidal capillarization proceeded concurrently with arterial blood supply during hepatocarcinogenesis. This study aimed to clarify the inducing role of arterialization in sinusoidal capillarization by investigating phenotypical, morphological and functional alterations to sinusoidal endothelial cells (SECs) in arterialized rat livers induced by portal branch ligation. At one week, after massive hepatic necrosis following ligation, the livers were restored to their normal architecture without causing post-necrotic fibrosis. At 12-21 weeks, they exhibited a normal histology except for mild pericellular fibrosis which developed along sinusoids or between adjacent hepatocytes. SECs expressed factor VIII-related antigen and showed a decrease in the number of fenestrae and porosity, still lacking any basement membrane but further retaining the functional capacity for carmine dye uptake. Stellate cells, while occasionally associated with large amounts of collagen bundles, contained many lipid droplets and expressed no alpha-smooth muscle actin, indicating a quiescent property. Kupffer cells were commonly found within the sinusoids. The present results indicate that arterialization of the liver induces a partial (but not complete) transition of SECs into capillary-type endothelial cells, suggesting that arterialization might be one of the factors which induce sinusoidal capillarization in the development of hepatocellular carcinoma.

Correction of cervical kyphosis using pedicle screw fixation systems

STUDY DESIGN

This retrospective study was conducted to analyze the clinical results in 30 patients with cervical kyphosis that had been treated using cervical pedicle screw fixation systems.

OBJECTIVES

To evaluate the effectiveness of a pedicle screw fixation procedure in correction of cervical kyphosis.

SUMMARY OF BACKGROUND DATA

Correction of cervical kyphosis is a challenging problem in the field of spinal surgery. There have been several reports regarding surgical correction of cervical kyphosis; however, there have been no detailed reports on correction of cervical kyphosis using a pedicle screw fixation procedure.

METHODS

Thirty patients with cervical kyphosis underwent correction and fusion using cervical pedicle screw fixation. Seventeen of 30 patients with flexible kyphosis (Group I) were managed by a posterior procedure alone. The remaining 13 patients with rigid or fixed kyphosis (Group II) had a combined anterior and posterior procedure.

RESULTS

The average preoperative cervical kyphosis of 29.4 degrees improved to 2.3 degrees after surgery and was 2.8 degrees at the final follow-up. In Group I patients, preoperative kyphosis of 28.4 degrees improved to 5.1 degrees at the final follow-up. In contrast, preoperative kyphosis of 30.8 degrees in Group II patients improved to 0.5 degree at the final follow-up. Solid fusion was achieved in all patients. There were two patients with transient nerve root complications related to pedicle screw instrumentation.

CONCLUSION

Cervical kyphosis in 30 patients was effectively corrected using a pedicle screw fixation procedure with no serious complications. Flexible kyphosis with segmental motion can be satisfactorily corrected by a single posterior procedure using pedicle screw fixation. However, circumferential osteotomies combined with a posterior shortening procedure involving a pedicle screw system are required to achieve the best correction of fixed kyphosis by bony union. Cervical pedicle screw fixation is the most advantageous instrumentation in the correction of cervical kyphosis.

Osteonecrosis of the femoral head. Simple varus intertrochanteric osteotomy

We present the long-term results of simple varus intertrochanteric osteotomy for osteonecrosis of the femoral head. We followed 26 hips in 20 patients, with a mean age at the time of surgery of 36 years, for a mean of 12.5 years. The mean varus angulation was 23 degrees. The outcome in 19 of the hips (73%) was good or excellent; seven (27%) had a fair or poor result, with four needing some form of prosthetic arthroplasty. Simple varus intertrochanteric osteotomy is indicated, even if the extent of the capital infarct comprises more than 50% of the diameter of maximum radial distance from the circumference, provided that after operation the medial necrotic lesion measures less than two-thirds of the weight-bearing area, and the superolateral bone is normal.

Osteonecrosis of the femoral head

We present the long-term results of simple varus intertrochanteric osteotomy for osteonecrosis of the femoral head. We followed 26 hips in 20 patients, with a mean age at the time of surgery of 36 years, for a mean of 12.5 years. The mean varus angulation was 23°.

The outcome in 19 of the hips (73%) was good or excellent; seven (27%) had a fair or poor result, with four needing some form of prosthetic arthroplasty.

Simple varus intertrochanteric osteotomy is indicated, even if the extent of the capital infarct comprises more than 50% of the diameter of maximum radial distance from the circumference, provided that after operation the medial necrotic lesion measures less than two-thirds of the weight-bearing area, and the superolateral bone is normal.

Nonoperative treatment of osteochondritis dissecans of the humeral capitellum

We examined 24 patients with osteochondritis dissecans of the humeral capitellum to determine the results of nonoperative treatment. The average age of the patients at the initial examination was 13.3 years (range, 11 to 16). All the patients were advised to stop heavy use of the elbow for 6 months. At the last examination, at a mean follow-up period of 5.2 years, 4 patients (17%) had no residual elbow pain, 7 (29%) had pain only with heavy activities, and 13 (54%) had pain with activities of daily living. Final radiographs were obtained for 15 lesions, of which 3 lesions were assessed as healed, 3 as improved, and 9 as not improved. Five of 11 lesions in the early stage and all 4 advanced lesions failed to show radiographic improvement. These results suggest that osteochondritis dissecans of the capitellum has only a slight tendency to heal, and that instability can cause failure of the lesion to heal.

Localization and ultrastructure of pulmonary dendritic cells during delayed-type hypersensitivity reactions in mice

Dendritic cells (DCs) are widely distributed in the airways and can serve as potent antigen-presenting cells. To clarify their involvement in the cell-mediated immune responses of the lung, we immunohistochemically investigated their distribution and kinetics during pulmonary delayed-type hypersensitivity (DTH) reactions induced in sensitized mice by intratracheal instillation of hapten. Cellular infiltrate appeared around the bronchiole and its accompanying blood vessel at 12 h after elicitation and progressively expanded by 48 h. As quantitated by computer-assisted morphometry, I-A(+) DCs and CD4(+) Th cells significantly increased in number around the bronchiole to a maximum at 24 h, whereas F4/80(+) macrophages were predominantly accumulated around the accompanying vessel with a peak at 48 h. Serial-section analysis revealed that DCs were colocalized with Th cells in the inflamed peribronchiolar tissue. Immunoelectron microscopy demonstrated that DCs found inside and around the capillaries and venules of peribronchiolar interstitium displayed round forms, indicating their emigration from here, while those situated far from the microvessels were elongated, often in close apposition to the lymphocytes. Mitosis of DCs was rarely seen. The present results suggest that peribronchiolar accumulation of DCs resulting from accelerated influx of blood-borne immature DCs and the interaction with T cells at the application site may play inducing roles in the development of pulmonary DTH reactions by enhancing the recruitment of macrophages.

Long-term results of multiple muscle transfer to reconstruct shoulder function in patients with birth palsy: eleven-year follow-up

We evaluated the long-term clinical results of multiple muscle transfer for reconstruction of shoulder function in 10 patients with birth palsy. Multiple muscle transfer consists mainly of Harmon's deltoid shift, Ober's biceps muscle transfer, and Hoffer's latissimus dorsi muscle transfer. The follow-up ranged from 5 to 14 years with an average of 10.5 years. Two of the 10 patients showed no improvement, one due to severely atrophied latissimus dorsi muscle, and the other who had not received Hoffer's latissimus dorsi muscle transfer. Except for these two patients, an averaged flexion and external angles were 114 degrees and 25 degrees, respectively. Harmon's deltoid shift and Hoffer's latissimus dorsi muscle transfer for reconstruction of shoulder function in patients with birth palsy have proven to be a useful method in reconstructing and maintaining the function of active elevation and external rotation of the shoulder.

The stability of reconstruction methods after thoracolumbar total spondylectomy. An in vitro investigation

STUDY DESIGN

After total spondylectomy, five types of spinal reconstruction techniques were compared biomechanically.

OBJECTIVES

To evaluate the stability provided by five reconstruction methods after total spondylectomy.

SUMMARY OF BACKGROUND DATA

Total spondylectomy presents a worst-case scenario for spinal reconstruction. However, few investigators have biomechanically investigated spinal reconstruction stability after total spondylectomy.

METHODS

Eight human cadaveric spines (T11-L5) were used. After intact analysis, a total spondylectomy was performed at L2 and reconstructed using Harms titanium mesh (Depuy-Motech, Warsaw, IN) as an anterior strut. Anterior, posterior, or circumferential instrumentation techniques were then performed using the Kaneda SR and ISOLA pedicle screw systems (AcroMed Corp., Cleveland, OH) as follows: 1) anterior instrumentation at L1-L3 with multisegmental posterior instrumentation at T12-L4 (AMP), 2) anterior instrumentation at L1-L3 with short posterior instrumentation at L1-L3 (ASP), 3) anterior instrumentation at L1-L3 (A), 4) multilevel posterior instrumentation at T12-L4 (MP), and 5) short posterior instrumentation at L1-L3 (SP). Nondestructive biomechanical testing was performed under axial compression, flexion-extension, and lateral bending loading modes.

RESULTS

Only circumferential instrumentation techniques (AMP, ASP) exhibited higher stiffness than the intact spine in all loading modes (P < 0.05). Short circumferential fixation provided more stability than did multilevel posterior instrumentation (P < 0.05). Multilevel posterior fixation provided more stiffness than did short posterior and anterior instrumentation alone (P < 0.05).

CONCLUSIONS

Only circumferential fixation techniques provide more stability than the intact spine in all testing modes. Short circumferential instrumentation provides more stability than multilevel posterior instrumentation alone and requires fewer levels of spinal fusion.

Changes in the orientation of collagen fibers on the superficial layer of the mouse tibial bone after denervation: scanning electron microscopic observations

This study was undertaken to evaluate the relationship between the mechanical stress loaded onto the bone and the orientation of collagen fibers formed by osteoblasts. The femoral, obturator, and sciatic nerves in the left posterior legs of 7-week-old mice were exposed and electroscissored to reduce the mechanical stress loaded onto the leg. Four weeks after operation, the tibial bones in the control and denervated legs were removed and observed by scanning electron microscopy (SEM) after NaOCl treatment. In the control right tibia, collagen fibers on the superficial bone matrix tended to be arranged parallel to the longitudinal axis of the bone. However, the arrangement of collagen fibers in the left tibia, which were immobilized for 4 weeks by denervation, was disorganized and ran in random directions. The findings suggest that the direction of collagen fibers in the bone changes in response to the mechanical stress loaded onto the bone, probably due to changes in the activity of osteoblasts in the denervated leg.

Posterior occipitocervical reconstruction using cervical pedicle screws and plate-rod systems

STUDY DESIGN

This retrospective study was conducted to analyze the clinical results in 26 patients with lesions at the craniocervical junction that had been treated by occipitocervical reconstruction using pedicle screws in the cervical spine and occipitocervical rod systems.

OBJECTIVES

To evaluate the effectiveness of pedicle screw fixation in occipitocervical reconstructive surgery and to introduce surgical techniques.

SUMMARY OF BACKGROUND DATA

Many methods of occipitocervical reconstruction have been reported, but there have been no reports of occipitocervical reconstruction using pedicle screws and occipitocervical rod systems for reduction and fixation.

METHODS

Twenty-six patients with lesions at the craniocervical junction underwent reconstructive surgery using pedicle screws in the cervical spine and occipitocervical rod systems. The occipitocervical lesions were atlantoaxial subluxation associated with basilar invagination, which was caused by rheumatoid arthritis in 19 patients and other disorders in 7. The lowest cervical vertebra of fusion in 16 patients was C2, and the remaining 10 patients underwent fusion downward from C3 to C7. Flexion deformity of the occipitoatlantoaxial complex was corrected by application of extensional force, and upward migration of the odontoid process was reduced by application of combined force of extension and distraction between the occiput and the cervical pedicle screws.

RESULTS

Solid fusion was achieved in all patients except two with metastatic vertebral tumors who did not receive bone graft for fusion. Correction of malalignment at the craniocervical junction was adequate, and postoperative magnetic resonance imaging showed improvement of anterior compression of the medulla oblongata. There were no neurovascular complications of cervical pedicle screws.

CONCLUSIONS

Occipitocervical reconstruction by the combination of cervical pedicle screws and occipitocervical rod systems provided the high fusion rate and sufficient correction of malalignment in the occipitoatlantoaxial region. Results of this study showed the effectiveness of cervical pedicle screw as a fixation anchor for occipitocervical reconstruction.

Biomechanical role of the intervertebral disc and costovertebral joint in stability of the thoracic spine. A canine model study

STUDY DESIGN

Biomechanical evaluation was performed to investigate the stability of the thoracic spine. Unilateral resection of the intervertebral disc, the rib head joint, and the costotransverse joint were sequentially performed, and nondestructive cyclic loading tests were conducted at each injury stage to examine the roles of the intervertebral disc and the costovertebral joint of the thoracic spine. The effects of each resection were three-dimensionally analyzed as the main motion and the associated coupled motions.

OBJECTIVE

To examine the role of the intervertebral disc and the costovertebral joint in stability of the thoracic spine.

SUMMARY OF BACKGROUND DATA

The effects of unilateral resection of the intervertebral disc and the costovertebral joints in the thoracic spine with the rib cage have not been documented three-dimensionally in a biomechanical study.

MATERIALS AND METHODS

Ten canine rib cage-thoracic spine complexes, consisting of the sixth to eighth ribs, the sternum and T5-T8 vertebrae, were used. Six pure moments along three axes, flexion-extension, lateral bending, and axial rotation, were applied to the specimen, and the angular deformation between T6-T7 was recorded by a stereophotogrammetric method. After the intact specimens were tested, staged resections were conducted in the following manner: partial resection of the T6-T7 intervertebral disc, performed as a resection of the anterior longitudinal ligament, the nucleus pulposus, and the annulus fibrosus on the approach side, leaving the posterior longitudinal ligament intact; resection of the right seventh rib head with the joint capsule; and resection of the right seventh costotransverse joint. At each stage, the main motion and associated coupled motions were determined three dimensionally.

RESULTS

The ranges of motion (ROM) in flexion-extension, lateral bending, and axial rotation were significantly increased after partial discectomy (P < 0.01). Moreover, along with large increases in the ROM of the main motions in left axial rotation and right lateral bending, coupled motions, expressed by right lateral bending and left axial rotation, showed marked increases after resection of the rib head joint (P < 0.05). The neutral zones also increased in lateral bending, axial rotation, and flexion-extension after partial discectomy (P < 0.01). A further increase in the neutral zone was observed in lateral bending after resection of the right seventh rib head (P < 0.01).

CONCLUSIONS

In this canine spine model, the intervertebral disc regulates the stability of the thoracic spine in flexion-extension, lateral bending, and axial rotation. Moreover, the articulation of the rib head with the vertebral bodies provides stability to the thoracic spine in lateral bending and axial rotation. Unilateral resection of the rib head joint after partial discectomy on the same side produces significant coupled motions in lateral bending and axial rotation, resulting in a significant decrease in thoracic spinal stability, and integrity.

Noninvasive assessment of the cardiac baroreflex: response to downward tilting and comparison with the phenylephrine method

OBJECTIVES

We studied the relation between changes in systolic blood pressure and RR interval during downward tilting in comparison with assessment of baroreflex sensitivity (BRS) measured by the phenylephrine method (Phe-BRS) and with measures of heart rate variability (HRV).

BACKGROUND

The method most extensively used for assessing BRS involves bolus injections of phenylephrine. Several noninvasive methods proposed to assess BRS have not been widely applied in the clinical setting.

METHODS

Sixteen healthy male volunteers were studied (mean age +/- SD 27.5+/-4.6 years). Arterial blood pressure using tonometry and electrocardiogram was simultaneously recorded. After 20 min of 70 degrees upright tilting, the table was returned to supine position at a speed of 3.2 degrees/s. Subsequently, BRS was assessed using an intravenous bolus injection of phenylephrine (2 to 3 microg/kg). Heart rate variability under resting conditions also was analyzed.

RESULTS

In all subjects, a beat to beat systolic blood pressure increase associated with corresponding RR interval lengthening was observed during downward tilting as well as during phenylephrine administration. During both testing procedures, these two variables showed linear correlation, and the slope of regression line during downward tilting (DT-BRS) correlated significantly with Phe-BRS (r = 0.79, p = 0.0003). The DT- and Phe-BRS also correlated significantly with the high frequency component of resting HRV (r = 0.70, p = 0.0023 for DT-BRS; r = 0.58, p = 0.0185 for Phe-BRS).

CONCLUSIONS

We conclude that in a small homogeneous group DT-BRS provided an assessment of reflex cardiac vagal function comparable to that obtained by the phenylephrine method.

Does spinal instrumentation influence the healing process of posterolateral spinal fusion? An in vivo animal model

STUDY DESIGN

An in vivo sheep model was used to investigate the effect of spinal instrumentation on the healing process of posterolateral spinal fusion.

OBJECTIVES

To examine the role of spinal instrumentation during the healing process of posterolateral fusion.

SUMMARY OF BACKGROUND DATA

In long bone fractures, internal fixation improves the union rate but does not accelerate the healing process. Spinal instrumentation also improves the fusion rate in spinal arthrodesis. However, it remains unclear whether the use of spinal instrumentation expedites the healing process of spinal fusion.

METHODS

Sixteen sheep underwent posterolateral spinal arthrodeses at L2-L3 and L4-L5 using equal amounts of autologous bone. One of those segments was selected randomly to be augmented with transpedicular screw fixation (Texas Scottish Rite Hospital spinal system). The animals were killed at 8 weeks or 16 weeks after surgery. Fusion status was evaluated by biomechanical testing, manual palpation, plain radiography, computed tomography, and histology.

RESULTS

Instrumented fusion segments demonstrated significantly higher stiffness than did uninstrumented fusions at 8 weeks after surgery. Radiographic assessment and manual palpation showed that the use of spinal instrumentation improved the fusion rate at 8 weeks (47% versus 38% in radiographs, 86% versus 57% in manual palpation). Histologically, the instrumented fusions consisted of more woven bone than the uninstrumented fusions at 8 weeks after surgery. The 16-week-old fusion mass was diagnosed biomechanically, radiographically, and histologically as solid, regardless of pedicle screw augmentation.

CONCLUSION

The current study's results demonstrated that spinal instrumentation creates a stable mechanical environment to enhance the early bone healing of spinal fusion.

Biomechanical studies of the rabbit patellar tendon after removal of its one-fourth or a half

Effects of the overstressing induced by the harvest of grafts from the patellar tendon on the mechanical properties and morphometry of remaining tendon were studied using a rabbit model. The width of the patellar tendon was reduced by one-fourth or one-half equally removing the medial and lateral portions; by this surgery, the cross-sectional area was decreased by 25 or 50 percent from the original area. After all the rabbits were allowed unrestricted activities in cages for 3 to 12 weeks, their patellar tendons were harvested for mechanical and histological studies. The one-fourth removal induced no significant changes in the mechanical properties, but significantly increased the cross-sectional area. In the case of one-half removal, tensile strength and tangent modulus did not change in some tendons, although the cross-sectional area increased significantly. In the other central half tendons, mechanical strength decreased markedly, while the cross-sectional area increased; hypercellular areas and breakage of collagen bundles were observed in these tendons. These results indicate that the patellar tendon has an ability of functionally adapting to overstressing by changing the cross-sectional area, while keeping the mechanical properties unchanged, if the extent of overstressing is less than 30 percent.

In vitro migratory potential of rat quiescent hepatic stellate cells and its augmentation by cell activation

In liver injury, hepatic stellate cells are considered to depart from the sinusoidal wall and accumulate in the necrotic lesion through migration and proliferation. In this study, we investigated the migratory capacity of quiescent stellate cells in vitro and analyzed the relationship with proliferative response. Freshly isolated stellate cells that were seeded in the upper chamber of Cell Culture Insert (Becton Dickenson, Franklin Lakes, NJ) started to migrate to the lower chamber at 1 day and increased in migration index to 19% at 2 days. Cells in the lower chamber were stretched in shape with many lipid droplets and showed quiescent properties, i.e., negative expression of alpha-smooth muscle actin (alpha-SMA) or platelet-derived growth factor receptor-beta (PDGFR-beta). Migratory capacity in quiescent cells was also shown in the Matrigel-coated insert. Matrix metalloproteinase-2 (MMP-2) messenger RNA expression was low just after isolation, but was enhanced as migration became prominent. Migrating cells further showed higher proliferative activity than resting ones. The presence of PDGF/BB and Kupffer cells accelerated stellate cell migration by the chemotactic mechanism and concurrently augmented proliferation, whereas that of dexamethasone and interferon-gamma (IFN-gamma) attenuated migration as a result of general suppression effects. Compared with quiescent ones, alpha-SMA and PDGFR-beta-positive activated stellate cells obtained by 14-day culture exhibited more rapid and prominent migration, being regulated by mediators in a similar manner as described previously. These data indicate that quiescent stellate cells undergo migration, which is linked to proliferation and enhanced by PDGF/BB and Kupffer cells, suggesting the involvement of this function in the initial phase of development of postnecrotic fibrosis.