Diagnostic sensitivity of predicted F-wave latency by age, height, and MCV

OBJECTIVES

The aim was to investigate whether minimum F-wave latency (Fmin) predicted by a multiple regression equation utilizing age, height, and motor nerve conduction velocity (MCV) (3-factor method) was clinically useful to detect Fmin abnormality in diabetic polyneuropathy (DP) and lumbosacral monoradiculopathy (RAD).

MATERIALS AND METHODS

Thirty-one DP patients (ulnar, tibial, and peroneal nerves) and 66 RAD patients (peroneal nerve) were investigated. The specificity and sensitivity of the 3-factor method were compared to those obtained by a univariate (height) regression method (1-factor method) and another multivariate (height and age) regression method (2-factor method).

RESULTS

In general satisfactory specificity was obtained with all three methods. In DP patients the tibial 3-factor method showed statistically lower sensitivity than the other two methods. There were no significant differences in diagnostic sensitivity among the three methods in two other nerves of the DP patients and the peroneal nerve of the RAD patients.

CONCLUSION

The 3-factor method was useful to estimate Fmin in normal subjects, but it was of little value in increasing the diagnostic sensitivity in DP and RAD patients. The 2-factor method was more appropriate for detecting DP.

A clinically oriented video-based system for quantification of eyelid movements

A field-worthy system was developed to quantify the eyelid movements in clinical sites. The system consists of a home-use charge-coupled device video camera, a processing unit, and a personal computer. A white marker of 4-mm diameter and 30-mg weight is attached to the lower margin of the upper eyelid. The processing unit automatically detects the vertical displacement of the upper edge of the marker. One marker is attached to each eye so that the movements of the both eyelids are measured with one camera simultaneously. The measurement error of the system was evaluated in experiments on eight healthy subjects and eight patients with eyelid paralysis. The mean of the absolute error of peak amplitudes occurring in 2 min was 0.81 mm, with the worst error being +1.7 mm. The reproducibility of the mean peak amplitude measured on five consecutive days was within 1 mm. The mean peak amplitudes of both eyes were measured preoperatively and postoperatively for approximately three months for three patients who were operated on to remove vestibular schwannoma. The results demonstrated basic clinical utility of the system.

Administration of granulocyte colony-stimulating factor enhances endothelialization and microvessel formation in small-caliber synthetic vascular grafts

OBJECTIVE

The purpose of this study was to determine whether systemic administration of granulocyte colony-stimulating factor (G-CSF) would promote endothelialization for small-caliber Dacron vascular grafts.

METHODS

We implanted 4-mm preclotted Dacron grafts in both carotids of 12 dogs. For a fair comparison, all dogs had a comparable platelet aggregation profile with platelet aggregation scores less than 30. Five dogs served as controls, and the others were given 7-day subcutaneous injections of G-CSF (10 microg/kg per day), starting on the seventh postoperative day. The effect of G-CSF was evaluated by white blood cell count, which showed a 3.7-fold (+/- 2.7-fold) increase at the end of treatment. Grafts were harvested at 4 weeks. All G-CSF grafts were patent, and one control occluded. Endothelial-like cell coverage averaged 80.8% on G-CSF grafts, but only 35.6% for control grafts (P <.0004). With the exclusion of the anastomotic pannus healing factor, the difference in endothelial-like cell coverage was even greater (68.5% vs 9.8%; P <.0001). Immunocytochemical staining and electron microscopy studies demonstrated endothelial cells. Light microscopy also showed that there were more microvessels on and in the G-CSF grafts than in the control grafts. This study suggests that G-CSF can enhance early endothelialization of small-caliber vascular grafts. Further studies to determine the proper dosage and timing are needed before clinical application can be recommended.

Racial and geographic differences of Wiberg's angle from 400 ultrasonographic normal hips in Italian and Brazilian infants younger than 3 months old

The Wiberg center edge angle (CEA) of 400 hip sonographies among 200 infants, 100 Italians and 100 Brazilians, aged from 15 days to 90 days, whose hip joints were considered normal, from the ultrasonographic point of view (1a and 1b) according to Graf's classification were measured. For the CEA measurements in the studied material, the authors used their own methodology developed for this purpose, which is based on basic geometric concepts and applied by one graphic computer program. In the studied material, the statistical analysis of the results obtained in the measurement of the CEA showed a better conformation of the acetabular roof complex in the Brazilian infants compared with the Italian.

Effect of antagonistic voluntary contraction on motor responses in the forearm

OBJECTIVE

We investigated the effects of voluntary contraction of agonist and antagonist muscles on motor evoked potentials (MEP) and on myoelectric activities in the target (agonist) muscle following transcranial magnetic stimulation (TMS).

METHODS

The left extensor carpi radialis (ECR) and flexor carpi radialis (FCR) muscles were studied in 16 healthy subjects. H reflexes, MEP induced by TMS, and background electromyographic (EMG) activity were recorded using surface electrodes at rest and during voluntary contraction of either agonist or antagonist muscles.

RESULTS

Voluntary contraction of antagonist muscles (at 10% of maximum contraction) enhanced the amplitudes of MEP for both muscles. The H reflex of the FCR muscle was inhibited by contraction (10% of maximum) of the ECR muscle. Background EMG activity did not differ between H-reflex trials and TMS trials. Enhancement of MEP amplitudes and background EMG activity during voluntary antagonist contraction was comparable in the two muscles. Appearance rate of MEP recorded by needle electrodes in response to subthreshold TMS was increased by antagonistic voluntary contraction.

CONCLUSION

Facilitation occurs during voluntary contraction of antagonist muscles. Differences between the effects of voluntary contraction of the ECR muscle for the MEP and the H reflex of the FCR suggest that cortical facilitatory spread occurs between agonist and antagonist muscles.

A new methodology for the measurement of the Wiberg angle in infants under 3 months

This article describes the measurement of the Wiberg center edge angle in infants under 3 months using sonographic images of their hips. In the literature review, there was no reference of the application of this angle in this particular age group. Thus, a methodology has been developed based upon the fact that, at this age, the acetabular roof constitutes a large portion of hyaline cartilage. In this way, it was concluded that it was not possible to apply the original Wiberg method since the center of the femoral head can be only estimated and not accurately determined in plain radiography. For this present study, 400 hips of 200 infants were analyzed. All these hips were classified as type 1a or 1b, according to Graf. The sonographic images were transferred to a Pentium computer through a video Spigot interface. The images were analyzed by software specially developed for this purpose. Since ultrasonography allows the exact recognition of the anatomical elements of the hip joint in young children, software provided the acetabular cartilaginous roof angle that corresponds to the center edge angle in adults. The authors believe that this method will be helpful in the early detection of morphological alterations in the hip joint.

Risk-adapted pre-emptive therapy for cytomegalovirus disease in patients undergoing allogeneic bone marrow transplantation

We prospectively evaluated a risk-adapted pre-emptive treatment with ganciclovir for CMV diseases in patients undergoing allogeneic bone marrow transplantation (BMT). High-level CMV antigenemia (10 or more positive cells on two slides) or CMV antigenemia at any level in patients with grade II-IV acute graft-versus-host disease (aGVHD) were chosen as risk factors. We also retrospectively evaluated virus reactivation in plasma using quantitative real-time polymerase chain reaction (PCR). Fifty patients were evaluable. None of the 27 patients with or without grade I aGVHD developed high-level CMV antigenemia or CMV disease. Among the 23 patients with grade II-IV aGVHD, 12 patients (52%) developed CMV antigenemia and were treated pre-emptively, of whom two developed CMV gastroenteritis or retinitis in spite of therapy. Six of the remaining 11 patients developed CMV gastroenteritis before CMV antigenemia was detectable. All of the eight patients with CMV diseases were successfully treated with ganciclovir and no deaths directly related to CMV disease occurred. In four of the seven evaluable patients with CMV gastroenteritis, real-time PCR was able to detect virus reactivation earlier than CMV antigenemia. Although our risk-adapted pre-emptive therapy effectively reduced CMV-related mortality, further refinements of this approach, particularly in the prevention of CMV gastroenteritis, may be achieved by incorporating real-time PCR.

Dynamic Changes of Smooth Muscle and Endothelial Markers in the Early Healing Process of Dacron Vascular Grafts in the Dog, Using RT-PCR

Previous studies of neointima formation on Dacron vascular grafts mainly focused on the late stages using immunohistochemistry staining for von Willebrand factor (vWF) and smooth muscle (SM) alpha-actin. However, it is impossible to use immunohistochemistry to study the early events of neointima formation, because graft samples lack sufficient cellular material. Therefore, we used reverse transcriptase-polymerase chain reaction (RT-PCR) to demonstrate dynamic changes of SM and endothelial markers during the early stages of neointima formation. Preclotted Dacron grafts were implanted in the descending thoracic aorta of 14 mongrel dogs. Specimens were retrieved at 1-4 weeks. Total RNAs were extracted from mid-portion of graft flow surfaces, and RT-PCR for vWF, SM myosin heavy chain (MHC), and SM alpha-actin were performed and expressed as a ratio to the ribosome s17 signal. SM MHC and vWF mRNA expression was low at 1-2 weeks but elevated at 3-4 weeks (P < 0.05). However, SM alpha-actin mRNA levels were expressed consistently throughout the study period. At 3-4 weeks, vWF mRNA expression was inversely correlated to thrombus formation on the graft flow surface. Increased expressions of SM MHC and vWF mRNA corresponded to the formation of neointima and an endothelial layer at the later stages. However, SM alpha-actin mRNA expression did not vary during the healing process. The application of RT-PCR should permit further studies of gene regulation in the early vascular graft healing process in vivo. This model can also be used to study the molecular events that are involved in SM cell differentiation.

Linkage between alpha(1) adrenergic receptor and the Jak/STAT signaling pathway in vascular smooth muscle cells

The Jak/STAT pathway is activated following stimulation of the type I angiotensin II receptor. To examine whether this pathway is shared among other G-protein-coupled receptors, we studied the linkage between the alpha(1) adrenergic receptor and this pathway. The alpha(1) agonist phenylephrine induced tyrosine phosphorylation of Jak2, Tyk2, and STAT1 in vascular smooth muscle cells. The phosphorylation of Jak2 was prevented by the alpha(1) receptor antagonists prazosin and chloroethylclonidine, but not by WB4101, and that of STAT1 was inhibited by prazosin and the Jak2 inhibitor AG490. After stimulation with phenylephrine, Jak2 and STAT1 were found to associate with alpha(1B) receptor. Phenylephrine stimulated the DNA binding activity of STAT1. Protein synthesis promoted by phenylephrine was inhibited by prazosin, AG490, and the introduction of a decoy oligonucleotide for STAT1. These results suggested that alpha(1) receptor is linked to the Jak/STAT pathway and that this pathway mediates alpha(1) agonist-induced smooth muscle hypertrophy.

Novel treatments after experimental brain injury

Perinatal hypoxic-ischaemic encephalopathy(HIE) is being studied in laboratory models that allow the delayed cascade of events triggered by the energetic insult to be examined in detail. The concept of the 'excitotoxic cascade' provides a conceptual framework for thinking about the pathogenesis of HIE. Major events in the cascade triggered by hypoxia-ischaemia include overstimulation of N-methyl-D-aspartate type glutamate receptors, calcium entry into cells, activation of calcium-sensitive enzymes such as nitric oxide synthase, production of oxygen free radicals, injury to mitochondria, leading in turn to necrosis or apoptosis. New experimental approaches to salvaging brain tissue from the effects of HIE include inhibition of neuronal nitric oxide synthase, administration of neuronal growth factors, and inhibition of the caspase enzymes that execute apoptosis. Recent experimental work suggests that these approaches may be effective during a longer 'therapeutic window' after the insult, because they are acting on events that are relatively delayed. Application of modest hypothermia may allow these agents to be neuroprotective at even longer intervals after hypoxia-ischaemia.

Enhanced endothelialization and microvessel formation in polyester grafts seeded with CD34(+) bone marrow cells

The authors have shown accelerated endothelialization on polyethylene terephthalate (PET) grafts preclotted with autologous bone marrow. Bone marrow cells have a subset of early progenitor cells that express the CD34 antigen on their surfaces. A recent in vitro study has shown that CD34(+) cells can differentiate into endothelial cells. The current study was designed to determine whether CD34(+) progenitor cells would enhance vascular graft healing in a canine model. The authors used composite grafts implanted in the dog's descending thoracic aorta (DTA) for 4 weeks. The 8-mm x 12-cm composite grafts had a 4-cm PET graft in the center and 4-cm standard ePTFE grafts at each end. The entire composite was coated with silicone rubber to make it impervious; thus, the PET segment was shielded from perigraft and pannus ingrowth. There were 5 study grafts and 5 control grafts. On the day before surgery, 120 mL bone marrow was aspirated, and CD34(+) cells were enriched using an immunomagnetic bead technique, yielding an average of 11.4 +/- 5. 3 x 10(6). During surgery, these cells were mixed with venous blood and seeded onto the PET segment of composite study grafts; the control grafts were treated with venous blood only. Hematoxylin and eosin, immunocytochemical, and AgNO(3 )staining demonstrated significant increases of surface endothelialization on the seeded grafts (92% +/- 3.4% vs 26.6% +/- 7.6%; P =.0001) with markedly increased microvessels in the neointima, graft wall, and external area compared with controls. In dogs, CD34(+) cell seeding enhances vascular graft endothelialization; this suggests practical therapeutic applications. (Blood. 2000;95:581-585)

Differentiation-inducing factor-1, a morphogen of dictyostelium, induces G(1) arrest and differentiation of vascular smooth muscle cells

Differentiation-inducing factor-1 (DIF-1) is a morphogen that induces differentiation of DICTYOSTELIUM: Recently, DIF-1 has been shown to inhibit proliferation and induce differentiation in tumor cells, although the underlying mechanisms remain unknown. In this study, we examined the effects of DIF-1 on the proliferation and differentiation of vascular smooth muscle cells, to explore novel therapeutic strategies for atherosclerosis. DIF-1 nearly completely inhibited DNA synthesis and cell division in mitogen-stimulated cells. DIF-1 inhibited the phosphorylation of the retinoblastoma protein and the activities of cyclin-dependent kinase (Cdk) 4, Cdk6, and Cdk2, which phosphorylate the retinoblastoma protein. DIF-1 strongly suppressed the expression of cyclins D1, D2, and D3, as well as those of cyclins E and A, which normally began after that of the D-type cyclins. The mRNAs for the smooth muscle myosin heavy chains SM1 and SM2 were expressed in quiescent cells in primary culture, and these expression levels decreased after mitogenic stimulation. In the presence of DIF-1, the rate of the reduction was significantly decelerated. Moreover, the addition of DIF-1 to dedifferentiated cells induced the expressions of SM1 and SM2, accompanied by a reduction in the level of SMemb, a nonmuscle-type myosin heavy chain. Therefore, DIF-1 seemed to interrupt a very early stage of G(1) probably by suppressing the expressions of the D-type cyclins. Furthermore, this compound may prevent phenotypic modulation and induce differentiation of vascular smooth muscle cells.

[Experiences with the alloplastic joint prosthesis of the interphalangeal joint]

The replacement of finger joints, especially of the proximal interphalangeal joint (PIP), remains an unsolved problem. Long-term results of conventional reconstructive procedures as well as previously available artificial joint implants have been disappointing. In a controlled study, 12 PIP-joints were replaced by a new type of total endoprosthesis as an alternative to joint fusion. The cementless prosthesis is unhinged and consists of metal joint surfaces. After a follow-up of 18 months, implantation of this metal prosthesis resulted in almost complete pain relief and an active range of movement of 58 degrees. The absolute gain in mobility, however, was only 6 degrees. A swan-neck deformity was found in nine out of 12 cases but corrective surgery was not required. The proximal half of the implant had to be exchanged in two cases due to loosening. All patients were satisfied with the result. The disparity between subjective acceptance by the patients, who clearly prefer joint replacement to fusion, and objective results demonstrates the necessity for further development in this field. The type of prosthesis used in this study seems to be a useful baseline tool which could be turned into a ingenious PIP-joint replacement by further development aiming at reduced abrasion, increased initial stability, a more individual configuration, to name just a few goals.

Characteristics of visual feedback in postural control during standing

In the present study, the visual feedback system in postural control was investigated. To suppress the vestibular and proprioceptive feedback paths, a subject stood on a force-measuring plate with a fixed back support. Because the subject's body was immovable under these conditions, the subject controlled a computer model which simulated body dynamics. Information on the sway angle of the model was fed visually. Under this condition, frequency response functions for the ankle moment in response to the sway angle were calculated. The experimental results suggest that the visual feedback system contains a large time delay and, consequently, the visual system does not by itself allow a subject to maintain an upright posture. Index Terms- Feedback control, frequency characteristics, identification, posture, visual sensory feedback.

Detection of a variety of Ser/Thr protein kinases using a synthetic peptide with multiple phosphorylation sites

A novel peptide with multiple phosphorylation sites, which we designated as multide, was developed to detect a wide variety of protein kinases in crude cell extracts. Multide, KKRKSSLRRWSPLTPRQMSFDC, has been designed to contain consensus sequences for various Ser/Thr protein kinases including cAMP-dependent protein kinase, protein kinase C, MAP kinases, and Ca(2+)/calmodulin-dependent protein kinases in a single peptide. In-gel protein kinase assay using multide was found to be very useful for analyzing the activities of protein kinases that are altered in response to various extracellular stimuli. The substrate specificities of the protein kinases thus detected were further determined by using five multide analogs with different phosphorylation sites.

Tumor suppressor p53 but not cGMP mediates NO-induced expression of p21(Waf1/Cip1/Sdi1) in vascular smooth muscle cells

Cyclin-dependent kinase inhibitor p21(Waf1/Cip1/Sdi1) has been suggested to be involved in the antiproliferative effect of nitric oxide (NO) in vascular smooth muscle cells (VSMCs). To elucidate the mechanism underlying NO-induced p21 expression, we investigated the roles of tumor suppressor p53 and the guanylate cyclase-cGMP pathway. The induction of p21 by the NO donor S-nitroso-N-acetylpenicillamine (SNAP) seemed to be due to transactivation because SNAP elevated the activity of p21 promoter but did not stabilize p21 mRNA and protein. Because SNAP did not stimulate the deletion mutant of p21 promoter that lacked p53 binding sites, we tested the involvement of p53. The expression level of p53 was down-regulated after mitogenic stimulation, whereas it was sustained in the presence of SNAP. SNAP markedly stimulated DNA binding activity of p53. Furthermore, SNAP failed to induce p21 in VSMCs obtained from p53-knock out mice and in A431 cells that contained mutated p53. The antiproliferative effect of SNAP also was attenuated in these cells. NO stimulates guanylate cyclase and its product cGMP has been shown to inhibit VSMC proliferation. However, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a guanylate cyclase inhibitor, did not prevent SNAP-induced p21 expression. 8-Bromo-cGMP, 3-isobutyl-1-methylxanthine, and their combination did not induce p21. Although 8-bromo-cGMP had a small antiproliferative effect, the elevation of cGMP concentration induced by SNAP was little throughout the G(1) phase. The antiproliferative effect of SNAP was not attenuated by Rp-8-bromoguanosine-3',5'-monophosphorothioate, an inhibitor of cGMP-dependent protein kinase. These results suggested that NO induces p21 through a p53-dependent but cGMP-independent pathway.

Striatal perfusion of indomethacin attenuates dopamine increase in immature rat brain exposed to anoxia: an in vivo microdialysis study

Using in vivo microdialysis and HPLC, we examined the effects of indomethacin on extracellular dopamine (DA) in the striatum of immature rats submitted to anoxia. Rat pups in two indomethacin groups received intrastriatal perfusion of either 1 mM or 5 mM indomethacin throughout the experiment. The DA level reached 1185+/-400% of the basal level during anoxia; in contrast, the peak levels of DA were only 307+/-63%, 153+/-35% in indomethacin groups (p<0.05). We consider that this suppression would be one of the mechanisms of the protective effect of indomethacin on hypoxic ischemic encephalopathy.

Juxtaglomerular cell tumor with retroperitoneal fibrosis and secondary immune-complex glomerulonephritis: a possible contribution of the renin angiotensin system to renal fibrosis

We present a case of a 25-year-old woman with a renin-secreting juxtaglomerular cell tumor, retroperitoneal fibrosis associated with glomerular hypertrophy, glomerulonephritis, and marked tubulointerstitial alterations. Myofibroblasts, as shown by positive immunostaining for alpha-smooth muscle actin, were found along with transforming growth factor-beta (TGF-beta) in the interstitium of the tumor-free kidney. Regarding the pathogenesis of renal fibrosis and glomerular hypertrophy, this case may provide evidence not only experimentally but also clinically that the renin-angiotensin system plays an important role because angiotensin II is known to induce renal fibrosis associated with increased TGF-beta and the appearance of myofibroblasts.

Phosphorylation and activation of Ca2+/calmodulin-dependent protein kinase phosphatase by Ca2+/calmodulin-dependent protein kinase II

Ca2+/calmodulin-dependent protein kinase phosphatase (CaMKPase) is a protein phosphatase which dephosphorylates autophosphorylated Ca2+/calmodulin-dependent protein kinase II (CaMKII) and deactivates the enzyme (Ishida, A., Kameshita, I. and Fujisawa, H. (1998) J. Biol. Chem. 273, 1904-1910). In this study, a phosphorylation-dephosphorylation relationship between CaMKII and CaMKPase was examined. CaMKPase was not significantly phosphorylated by CaMKII under the standard phosphorylation conditions but was phosphorylated in the presence of poly-L-lysine, which is a potent activator of CaMKPase. The maximal extent of the phosphorylation was about 1 mol of phosphate per mol of the enzyme and the phosphorylation resulted in an about 2-fold increase in the enzyme activity. Thus, the activity of CaMKPase appears to be regulated through phosphorylation by its target enzyme, CaMKII.

Accelerated healing of Dacron grafts seeded by preclotting with autologous bone marrow blood

> Studies have suggested that bone marrow-derived cells in the circulation may have the capacity and potential to endothelialize and heal vascular graft surfaces. We have investigated whether accelerated endothelialization could be achieved for Dacron grafts seeded by preclotting with bone marrow blood (BMB). Five 8 mm x 6 cm Dacron grafts seeded and preclotted with BMB and four controls preclotted with peripheral blood were implanted in the descending thoracic aorta (DTA) of mongrel dogs for 2 and 4 weeks. Two additional BMB DTA grafts were studied for 3 months. Five pairs of BMB and control grafts (4 mm x 6 cm) were bilaterally implanted into the carotids of dogs for 1 week and five pairs for 4 weeks. All grafts remained patent. BMB seeding/preclotting was a simple, effective method to accelerate early graft endothelialization without increasing thrombogenicity. Further studies are needed before clinical application can be recommended.