Interleukin-1, tumor necrosis factor alpha, and interleukin-17 synergistically up-regulate nitric oxide and prostaglandin E2 production in explants of human osteoarthritic knee menisci

OBJECTIVE

In osteoarthritis (OA), a combination of biochemical and biomechanical factors may damage both menisci and articular cartilage. Nitric oxide (NO) and prostaglandin E2 (PGE2) have been implicated as mediators of inflammation in OA. The goals of this study were to determine if menisci from patients with OA produce NO and PGE2, and if the proinflammatory cytokines interleukin-1beta (IL-1beta), tumor necrosis factor a (TNFalpha), and IL-17 augment NO and PGE2 production by these tissues.

METHODS

Menisci were obtained from 17 patients (age 47-75 years) undergoing total knee replacement for OA. Tissue explants were cultured alone or with IL-1beta, IL-17, or TNFalpha, and the release of NO and PGE2 from the tissue as well as the presence of type 2 nitric oxide synthase (NOS2) and cyclooxygenase 2 (COX-2) antigens were measured.

RESULTS

All menisci constitutively produced NO, and significant increases in NO production were observed in the presence of IL-1beta, TNFalpha, or IL-17 (P < 0.05). The combination of IL-17 and TNFalpha significantly increased NO production compared with either cytokine alone. Basal and cytokine-stimulated NO synthesis was inhibited by the NOS inhibitors NG-monomethyl-L-arginine or N-3-aminoethylbenzylacetamidine (1400W). IL-1beta significantly increased PGE2 production. The combination of IL-1beta and TNFalpha had an additive effect on PGE2 production, while addition of IL-17 to TNFalpha or IL-1beta synergistically enhanced PGE2 production. Inhibition of NO production by 1400W significantly increased IL-1beta-stimulated PGE2 production, and inhibition of PGE2 production by the COX-2 inhibitor N-[2-(cyclohexyloxy)-4-nitrophenyl]-methanesulfonamide significantly increased IL-17-stimulated NO production.

CONCLUSION

Menisci from humans with OA spontaneously produced NO and PGE2 in a manner that was synergistically or additively augmented by cytokines. NO and PGE2 exhibited reciprocal regulatory effects on one another, suggesting that pharmaceutical agents designed to inhibit NOS2 or COX-2 production may in fact be influencing both pathways.

[Prospective study to compare high-resolution computed tomography and magnetic resonance imaging in the detection of pancreatic neoplasms: use of intravenous and oral MR contrast media]

PURPOSE

To compare thin-section hydro-CT and MRI in the detection of pancreatic neoplasms. Evaluation of an oral, superparamagnetic contrast agent (OMP) for pancreatic MRI.

MATERIAL AND METHODS

45 patients with suspected pancreatic neoplasms were examined with consecutive thin-section helical CT (Hydro-CT, 3/6/3, 130 ml Ultravist, Schering) and MRI (1.0 T, breath-holding, T1w-GRE, T1w-GRE fat-sat, T2w-TSE). The MRI protocol included precontrast studies, studies after oral administration of OMP (Abdoscan, Nycomed Amersham) and studies after administration of OMP and Gadodiamide i.v. (Omniscan, Nycomed Amersham). All images were assessed by two independent radiologists in a blinded fashion. Radiologic diagnosis was correlated with histology or clinical follow-up (> or = 3 month).

RESULTS

39 patients could be included in analysis. In 13 cases a pancreatic neoplasm was proven by histology. Thin-section hydro-CT and MRI showed no statistically significant differences for the detection of pancreatic neoplasia. The sensitivity of helical hydro-CT was superior compared to MRI (88.5% vs. 65.44/73.1%/76.9%). The specificity of MRI was superior compared to helical hydro-CT (86.5% vs. 94.2%/90.4%/88.5%).

CONCLUSION

Thin-section hydro-CT and MRI show similar results for the detection of pancreatic neoplasms. Compared to thin-section helical CT, MRI still has the drawbacks of much more time consumption and, still, lower spatial resolution. The use of an oral, superparamagnetic contrast agent added no advantage for pancreatic MRI.

Intramedullary screw fixation of Jones fractures

BACKGROUND

Jones fractures of the fifth metatarsal can be stabilized using intramedullary screw fixation techniques. A range of screw diameters from 4.5 mm to 6.5 mm can be used, but the optimal screw for this procedure has yet to be defined. In clinical practice, we have observed that failure is more likely when smaller diameter screws are used.

METHODS

Experimental Jones fractures were created in 23 pairs of human cadaver fifth metatarsals, which were fixed using either 5.0 mm or 6.5 mm screws. Fracture stiffness and pull-out strengths were measured for either screw type and their relationships with bone mineral density and medullary canal diameter were determined.

RESULTS

There was no significant difference in the bending stiffness of fractures stabilized with 5.0 mm and 6.5 mm screws; however, different mechanisms of failure were noted for either screw type. Poor thread purchase within the medullary canal was noted with the 5.0 mm screws, while excellent purchase was noted with 6.5 mm screws. Pull-out strength testing revealed significantly higher pullout strengths for the larger 6.5 mm screws. There was no significant difference in bone mineral density or medullary canal diameter between right and left metatarsals.

CONCLUSIONS

Fifth metatarsals can often accommodate a 6.5 mm screw for the stabilization of Jones fractures. Larger diameter screws did not result in greater fracture stiffness in our model, but did result in significantly greater pull-out strengths.

CLINICAL RELEVANCE

Larger diameter screws may be more appropriate for intramedullary screw fixation of Jones fractures.

The effect of dynamic mechanical compression on nitric oxide production in the meniscus

OBJECTIVE

The menisci play an important role in the biomechanics of the knee, and loss of meniscal function has been associated with progressive degenerative changes of the joint in rheumatoid arthritis as well as in osteoarthritis. However, little is known about the underlying mechanisms that link meniscal injury or degeneration to arthritis. Meniscal fibrochondrocytes respond to environmental mediators such as growth factors and cytokines, but the influence of mechanical stress on their metabolic activity is not well understood. Nitric oxide (NO) is believed to play a role in mechanical signal transduction, and there is also significant evidence of its role in cartilage and meniscus degeneration. The goal of this study was to determine if meniscal fibrochondrocytes respond to mechanical stress by increasing NO production in vitro.

DESIGN

Explants of lateral and medial porcine menisci were dynamically compressed in a precisely controlled manner, and NO production, nitric oxide synthase antigen expression and cell viability were measured. The relative responses of the meniscal surface and deep layers to dynamic compression were also investigated separately.

RESULTS

Meniscal NO production was significantly (P< 0.01) increased by dynamic compression in both the medial and lateral menisci. Dynamically compressed menisci contained inducible nitric oxide synthase antigen, while uncompressed menisci did not. Significant (P< 0.05) zonal differences were observed in basal and compression-induced NO production.

DISCUSSION

Our findings provide direct evidence that dynamic mechanical stress influences the biological activity of meniscal cells. These results suggest that NO production in vivo may be in part regulated by mechanical stress acting upon the menisci. Since NO affects matrix metabolism in various intraarticular tissues, alterations in the distribution and magnitude of stress in the menisci may have important metabolic as well as biomechanical consequences on joint physiology and function.

Predictors of left ventricular function after acute myocardial infarction: effects of time to treatment, patency, and body mass index: the GUSTO-I angiographic experience

BACKGROUND

Despite the significant survival benefit associated with successful reperfusion therapy for acute myocardial infarction, global indices of outcome left ventricular function, such as ejection fraction, have often demonstrated little or no improvement. Although these measurements are confounded by numerous clinical, physiologic, and angiographic variables, no comprehensive analysis of this issue in a large series of patients is available. We used the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) database to better understand this phenomenon by determining independent predictors of left ventricular function and their interplay with regard to outcome ventricular function and improvement in function during the initial postinfarction week.

METHODS

Ninety-minute and 5- to 7-day posttreatment global and regional indices derived from left ventriculograms were analyzed from a population of 676 patients. These observations were combined with clinical data to describe independent determinants of ventricular function outcome.

RESULTS

Clinical factors predictive of global and regional ventricular function as well as improvement in function between 90 minutes and 5 to 7 days included time to treatment, early infarct-related artery flow grade, and body mass index. These same factors contribute significantly to compensatory hyperkinesis of the noninfarct zone, which is critical to maintenance of global ventricular function during this time period.

CONCLUSIONS

The ventricular function benefits of early complete reperfusion after myocardial infarction are readily demonstrable after adjustment for multiple covariables and include (1) maintenance of global ventricular function and (2) prevention or delay in ventricular dilatation.

Experimental preseeding of the STARFlex atrial septal occluder device with autologous cells

Devices used in interventional cardiology are permanent implants. However, most of the devices fulfill only a temporary function. For example, atrial septal defect (ASD) occluders serve as mechanical shields until complete in- and overgrowth of the occluding device by endogenous tissue from the defect edges has occurred. Thereafter, the foreign body material of the devices is no longer needed and bears potential long-term adverse effects. The concept of "biodegradable" occluder devices that act as transient mechanical shields to close the defects and as scaffolds for overgrowth with autologous tissue is, therefore, tempting. Since rapid and complete ingrowth as well as coverage by firm tissue is a prerequisite for any such "biological" occluder devices, the feasibility and short-term in vivo response to STARFlex devices preceeded with autologous cells was studied in an experimental sheep model. The experiments demonstrated that autologous cell preceeding of cardiovascular implants is technically feasible. Cells survived the mechanical stress of device implantation. A precoating of conventional STARFlex occluders led to an increased cellular density after cell seeding of the device, an increased resistance of the precultured cytolayer against mechanical stress, and a significantly higher poststress viability of "implanted" cells. Experimental closure of ASD using autologous-cell preseeded STARFlex devices was uncomplicated. In the sheep model this led to rapid, complete, and firm ingrowth of the device into the adjacent atrial tissue. A thicker layer of young fibrous granulation tissue in organization was found on the preceeded devices compared with the unseeded control group after 4 weeks in vivo. Currently, an increased thrombogenicity limits in vivo application.

[A new combined surgical interventional method for univentricular palliation of congenital heart defects]

Total cavo-pulmonary anastomosis is frequently performed to palliate patients with a broad variety of congenital heart defects with functionally univentricular hearts precluding biventricular circulation. In patients with risk factors for primary repair a stepwise approach is frequently chosen with initial creation of an aorto-pulmonary shunt followed by a Glenn anastomosis or hemifontan procedure. Finally a total cavo-pulmonary connection is completed surgically. The aim of this feasibility study was to develop a combined surgical-interventional approach for creation of a total cavo-pulmonary anastomosis which reduces the number of surgical interventions, precludes extracorporeal circulation and intracardiac sutures, putting the patients at risk for subsequent rhythm disturbances.

METHODS

A Glenn anastomosis was created in 10 sheep without cardio-pulmonary bypass. The superior vena cava was banded superior to the cavo-atrial junction leaving a minimal lumen for subsequent interventional balloon dilatation and implantation of a stent graft. A 15 mm Gore-Tex tube was sutured around the inferior vena cava intrapericardially to provide resistance for subsequent interventional stent implantation. Total cavo-pulmonary anastomosis was completed interventionally by dilating the banded vena cava superior and connection of the inferior vena cava to the superior vena cava by implanting an Aneurx covered stent graft.

RESULTS

All animals survived the combined surgical-interventional procedure. Stent deployment was possible without causing obstruction to the hepatic veins. Neither stent dislocation nor rhythm disturbances were encountered.

CONCLUSIONS

Total cavo-pulmonary anastomosis can be achieved without intracardiac sutures and cardio-pulmonary bypass by use of a combined surgical-interventional approach using the Aneurx covered stent graft.

Chronic lateral epicondylitis of the elbow: A prospective study of low-energy shockwave therapy and low-energy shockwave therapy plus manual therapy of the cervical spine

OBJECTIVE

To compare the effects of extracorporeal shockwave therapy (ESWT) alone with a combination of ESWT and manual therapy of the cervical spine in treating chronic tennis elbow.

DESIGN

Prospective, matched single-blind control trial.

SETTING

University hospital clinic.

PATIENTS

Thirty patients with unilateral chronic tennis elbow, an unsuccessful conservative therapy during the 6 months before referral, and clinical signs of cervical dysfunction (eg, pressure pain at the C4-5 and/or C5-6 level, protraction of the head).

INTERVENTIONS

Three times at weekly intervals all patients received 1000 shockwave impulses of an energy flux density of.16mJ/mm(2) at the lateral elbow. Additionally, they underwent manual therapy of the cervical spine and the cervicothoracic junction 10 times (group I). For each patient, a control matched by age (3-yr range) and gender at first conservative treatment was drawn at random from 127 patients who had undergone low-energy shockwave therapy in the same unit in the past 3 years (group II). Follow-up examinations took place at 12 weeks and at 12 months.

MAIN OUTCOME MEASURES

The Roles and Maudsley outcome score at 12 months, defining an excellent or good result with no or only occasional discomfort without limitation of activity and range of motion.

RESULTS

Neither group differed statistically before the study, with a poor rating for all patients (p >.05). At 12 months, there was still no significant difference, with the outcome being excellent or good in 56% in group I, and in 60% in group II (p >.05). Each group showed significant improvement compared with the respective prestudy evaluation (p <.0001).

CONCLUSION

ESWT may be an effective conservative treatment method for unilateral chronic tennis elbow. The efficacy of additional cervical manual therapy for lateral epicondylitis remains questionable.

Long-term results of arthroscopic partial lateral meniscectomy in knees without associated damage

We evaluated the outcome of partial lateral meniscectomy of 31 knees in 29 patients whose knees were otherwise normal. The mean follow-up was 10.3 years.

According to the Lysholm score, 14 knees were rated as excellent, four as good, five as fair and eight as poor, with a mean score of 80.5 points. Radiologically, only one lateral compartment was classified as grade 0, eight as grade 1, nine as grade 2, 11 as grade 3, and two as grade 4 according to Tapper and Hoover. No significant (p < 0.05) correlation was found between the amount of tissue resected and the subjective, clinical and radiological outcome.

Although early results of lateral meniscectomy may be satisfactory, we have demonstrated that in the long term there was a high incidence of degenerative changes, a high rate of reoperation (29%) and a relatively low functional outcome score.

Transcatheter recanalization of the left main pulmonary artery after four years of complete occlusion

A technique for transcatheter "reconstruction" of a completely occluded left pulmonary artery using radiofrequency perforation with subsequent balloon dilation and stent implantation is reported in a 7-year-old child. It is shown that transcatheter radiofrequency perforation can still be effective years after the occlusion of a vessel.

Long-term outcome of operative or nonoperative treatment of anterior cruciate ligament rupture--is sports activity a determining variable?

The purpose of this study was to evaluate the long-term clinical outcome of operative versus nonoperative treatment of anterior cruciate ligament (ACL) deficiency and to define its relationship with sports activity. Forty-six patients (37 male, 9 female, mean age, 33.6 +/- 8.0 years) who underwent open ACL reconstruction using patellar tendon autograft and 25 patients (18 male, 7 female, mean age, 32.3 +/- 9.9 years) who were treated nonoperatively were evaluated by the same two examiners at 5 - 7 and 10 - 13 years following injury. The evaluations included objective and subjective scoring (Lysholm, OAK, IKDC), instrumented testing (Cybex, KT 1000), radiographic evaluation, and assessments of sports activity, with respect to type, frequency and associated symptoms. According to Lysholm, OAK and IKDC scores, the operative group performed significantly (p < 0.05) better and was able to maintain increased involvement in sports, although both groups participated less over time. However, risks for degenerative joint changes were similar for both the operative and the nonoperative group. A significant (p < 0.05) correlation between participation in high-risk pivoting sports, such as soccer or basketball and osteoarthritic changes could be found for the nonoperative group, only. Sports activity represents an important variable not only affecting the outcome, but also influencing treatment decisions following ACL injuries.

Long-term results of arthroscopic partial lateral meniscectomy in knees without associated damage

We evaluated the outcome of partial lateral meniscectomy of 31 knees in 29 patients whose knees were otherwise normal. The mean follow-up was 10.3 years. According to the Lysholm score, 14 knees were rated as excellent, four as good, five as fair and eight as poor, with a mean score of 80.5 points. Radiologically, only one lateral compartment was classified as grade 0, eight as grade 1, nine as grade 2, 11 as grade 3, and two as grade 4 according to Tapper and Hoover. No significant (p < 0.05) correlation was found between the amount of tissue resected and the subjective, clinical and radiological outcome. Although early results of lateral meniscectomy may be satisfactory, we have demonstrated that in the long term there was a high incidence of degenerative changes, a high rate of reoperation (29%) and a relatively low functional outcome score.

[Recurrence of cystic adventitial degeneration of the popliteal artery--magnetic resonance tomography and MR angiography]

Adventitial cystic disease is a rare disorder characterized by mucin-containing cysts of the adventitial tissue. The condition has a predilection for the popliteal artery. Men are predominantly affected, usually around the fourth decade. We report of a case of recurrent adventitial cystic disease and the possibilities of modern cross-sectional imaging. In particular we discuss the advantages of magnetic resonance imaging and magnetic resonance angiography for the diagnosis of this condition. Furthermore, the etiology and the possibilities of surgical treatment are illustrated.

Tibial tunnel enlargement following anterior cruciate ligament reconstruction with patellar tendon autograft

PURPOSE

The purpose of this study was to prospectively evaluate changes in the tibial bone tunnel following endoscopic anterior cruciate ligament (ACL) reconstruction with patellar tendon autograft. We used computed tomography (CT) sequentially to monitor the time course of these changes over a 2-year period and correlated the results to clinical outcome and instrumented laxity measurements.

TYPE OF STUDY

Case series.

METHODS

Thirty-four patients (11 women, 23 men; mean age, 26.4 +/- 4.5 years) who underwent endoscopic patellar tendon ACL reconstruction, were evaluated clinically according to IKDC, Lysholm, and Tegner scores as well as with respect to changes in tibial tunnel morphology over a 2-year period. Subsequent CT scans were performed at 1 and 6 weeks and at 3, 6, 12, and 24 months postoperatively. The tibial bone tunnel was measured in the sagittal and coronal planes at 5 different levels (L1 to L5).

RESULTS

The diameters of the tibial tunnel increased an average overall by 30.6% in the sagittal plane and 16.4% in the coronal plane within 2 years. The enlargement was significantly higher (P <.05) in the mid portion of the tunnel (L 2/3: 44.0% and 47.9% in the sagittal and 29.8% and 29.9% in the coronal plane, respectively), which resulted in a uniform cavity-type appearance. The percentage of change in tunnel size was significantly higher (P <.05) within the first 6 weeks following surgery compared with all other time intervals. No correlation between the amount of tunnel enlargement and the clinical results or between tunnel enlargement and KT-1000 measurements could be detected.

CONCLUSIONS

Endoscopic ACL reconstruction is associated with tibial tunnel enlargement, which is already present within weeks following surgery. However, no negative effects on the clinical results were found over a 24-month period in our study population.

The incidence of combined facial and cervical spine injuries

BACKGROUND

The association between facial and cervical spine injuries has been documented. However, only severe spinal injuries were included in previous analyses. It was the purpose of this study to evaluate the incidence of and risk factors for these injury combinations including the complete injury spectrum.

METHODS

Between 1995 and 1997, 4,907 patients with cervical spine injuries were treated at our hospital. One hundred five (2.14%) of these patients had suffered a concomitant facial injury. This group was compared with the group of patients with cervical spine injury but without facial trauma.

RESULTS

The majority of cases (98%) consisted of minor lesions to both regions. With increasing severity of cervical spine trauma, the risk for facial injury increased. Age and male gender represent significant (p < 0.05) risk factors for combined injuries.

CONCLUSION

Patients sustaining cervical spine trauma have a small but real chance of injuring their face as well. The cervical spine must be examined carefully, whenever facial injuries are present.

[Computer-assisted retrograde drilling of osteochondral lesions of the talus]

Treatment principles of osteochondral lesions of the talus usually consist of debridement of the chondral part and methods that attempt to stimulate revascularization of the necrotic bony part of the lesion. The latter is mostly achieved through multiple drilling of the subchondral zone. Dorsomedial talar dome lesions are frequently inaccessible with antegrade drilling techniques. In addition, if the cartilage surface over the bony lesion is still intact, it can be injured by antegrade drilling. To overcome these potential problems, retrograde drilling techniques have been developed using drill guides or intraoperative fluoroscopy. Our proposed method of computer-assisted retrograde drilling is an advancement of these techniques. The use of 3D navigation provides the possibility for placing a guide wire exactly in the center of the lesion defined on preoperative MRI or CT scans. This guide wire can then be overreamed with cannulated reamers followed by retrograde bone grafting of the lesion or allows multiple retrograde drilling of the subchondral plate using a parallel drill guide. We found that computer-assisted retrograde drilling could improve precision, avoid misplacement of guide wires, and reduce the time of surgery and intraoperative fluoroscopy.

Osteochondral lesions of the talus: computer-assisted retrograde drilling--feasibility and accuracy in initial experiences

The authors developed a minimally invasive method with computer-assisted navigation for retrograde drilling of osteochondral lesions of the talus. Planning of the pathway and adjustment of the targeting device were performed outside the operating room. In 10 cadavers and four patients, accuracy of pin placement was in the range of 1.0-3.5 mm.

Transcatheter retrieval and repositioning of an Amplatzer device embolized into the left atrium

A transcatheter technique is described for stabilization and retrieval of an embolized Amplatzer device, which was inadvertently deployed in the left atrium of a 2-year-old girl with hemodynamically significant atrial septal defect within the fossa ovalis. Since surgery was not available for immediate device retrieval, transcatheter means were chosen to prevent embolization of the device into the mitral valve. After stabilizing the device by creating a guidewire circuit through the wire mesh of the right atrial disk, the Amplatzer device was repositioned through the interatrial defect by snaring the microscrew. No residual shunting and perfect device position was recorded during Doppler echocardiography directly after the procedure as well as 1, 2, and 120 days after the intervention. Cathet. Cardiovasc. Intervent. 51:297-300, 2000.

Endovascular stenting as an emergency treatment for neonatal coarctation

We describe a neonate with critical coarctation of the aorta. Since treatment with Prostaglandin E1 had failed to reopen the arterial duct, and surgery was deemed to be associated with an unacceptably high risk in this unstable neonate, it was decided to perform balloon dilation of the coarctation as a palliative procedure to stabilize the patient. Balloon angioplasty failed to reduce the pressure gradient across the coarctation, so a stent was implanted retrogradely as an emergency procedure. Subsequently, the stented segment was resected surgically and end-to-end anastomosis created without complications at seven months of age.

[Surgical stabilization of per- and subtrochanteric femoral fractures with the gamma nail]

BACKGROUND

From 1992 through 1997 96 patients with per- or subtrochanteric femur fractures were treated with a Gamma nail. We retrospectively evaluated the influence of patient age, additional diseases, type of fracture, time of operation, type of implant (short/long Gamma nail) and surgical approach (open/closed reduction) on the mobility of the patients, healing of the fractures on radiographs, and possible complications.

PATIENTS AND METHODS

The average patient age was 72.5 years (range 27 to 101). There were 27 male and 69 female patients. Surgery was performed 1.19 (0-10) days after injury. At 3, 6, and 12 months after surgery radiographs of the involved hip joint and femur were obtained and the degree of mobility was assessed.

RESULTS

Additional diseases, type of fracture, time of operation, type of implant (short/long Gamma nail) and surgical approach (open/closed reduction) did not influence mobility of the patients, healing of the fractures on radiographs or rate of complications. It was more difficult to mobilize older patients (P < 0.001). After 1 year 97% of all fractures had healed on radiographs. In 15 patients (18%) complications occurred due to technical errors using the Gamma nail.

DISCUSSION

With the Gamma nail stable osteosynthesis of per- and subtrochanteric femur fractures is obtained independently of the fracture classification. Patients can be mobilized immediately. Technical errors must be avoided.

Is screw divergence in femoral bone-tendon-bone graft fixation avoidable in anterior cruciate ligament reconstruction using a single-incision technique? A radiographically controlled cadaver study

Interference screw fixation of patellar tendon bone-tendon-bone grafts for anterior cruciate ligament reconstruction has proven to be a method with high pullout strength if screw divergence is avoided. Twenty-four fresh-frozen cadaveric human knees were used to identify the ideal position for a portal and an optimal knee flexion angle to obtain parallel placement of screw and bone block. On all specimens, anterior cruciate ligament reconstruction was performed using a single-incision technique. In the first part of this study, screw placement was analyzed in the frontal plane. In the second part, screw placement was investigated in the sagittal plane, measuring the additional flexion required between femoral tunnel drilling (at 60 degrees of knee flexion) and screw insertion to obtain parallel screw placement. For both part I and II, image intensification was used. In the third part, femoral screw placement was carried out through a paraligamentous approach and with additional flexion of 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, and 60 degrees. This study shows that screw placement with minimal divergence in the frontal and sagittal planes can be achieved by inserting the screw through a nearly central portal and flexing the knee an additional 35 degrees to 40 degrees.

Bioabsorbable polyglyconate interference screw fixation in anterior cruciate ligament reconstruction: a prospective computed tomography-controlled study

PURPOSE

It was the purpose of the study to evaluate a new polyglyconate bioabsorbable interference screw for graft fixation in anterior cruciate ligament (ACL) reconstruction.

TYPE OF STUDY

Prospective randomized.

MATERIALS AND METHODS

Forty patients who underwent endoscopic ACL reconstruction were included in the study and randomized intraoperatively. Group A consisted of 20 patients (6 women, 14 men; mean age, 29.6 years) who had femoral bone block fixation with a bioabsorbable interference screw and tibial fixation with a titanium interference screw. Group B included 20 patients (5 women, 15 men; mean age 29.6 years) who had fixation of both femoral and tibial bone blocks with titanium interference screws. There was no significant difference between the groups with regard to age, gender, height, weight, time from injury to surgery, activity level, and concomitant injuries.

RESULTS

Clinical results (using IKDC, Lysholm, Tegner scores) of the 2 groups as well as instrumented laxity measurements (KT-1000) did not show significant (P >.05) differences at any stage of follow-up. No complications with respect to graft fixation could be found. Computed tomography scans, performed within the first postoperative week, at 6 weeks, and at 3, 6, 12, and 24 months postoperatively revealed a uniform picture for all patients within the groups, showing completed screw degradation at 12 months in group A.

CONCLUSION

Polyglyconate interference screw fixation for patellar tendon grafts has not been found to be associated with increased clinical complications or significant osteolysis. It provided equivalent fixation and clinical results compared with titanium screws. However, replacement of the screw with bone did not take place for up to 3 years postoperatively.

[Transplant fixation by anterior cruciate ligament reconstruction. Metal vs. bioabsorbable polyglyconate interference screw. A prospective randomized study of 40 patients]

To overcome some of the potential problems (e.g. hardware removal during revision surgery) of metal interference screws used for patellar tendon anterior cruciate ligament reconstruction, bioabsorbable screws have recently been introduced. Forty patients who underwent endoscopic ACL reconstruction using patella tendon autograft were included in the study, they were randomized intraoperatively to either Group A (femoral bone block fixation: polyglyconate screw; tibial: metal screw) or Group B (both bone blocks fixed with metal interference screws). The patients were evaluated clinically preoperatively as well as 6 weeks, 3 months 12 months and 24 months post op. Lysholm Score at 24 months was 98.1 +/- 2.3 for Group A and 97.7 +/- 3.0 for Group B. Tegner Score was 7.4 +/- 1.1 for Group A and 7.5 +/- 0.8 for Group B. Two years post op overall IKDC-Score for group A was 5.6% normal, 88.8% nearly normal and 5.6% abnormal. The result for group B was 11.1%, 77.8% and 11.1%, respectively. KT-1000 (at 89 N) at two years revealed a side to side difference of 1.5 +/- 0.3 mm (Group A) and 1.6 +/- 0.7 (Group B). The results of the two groups did not show significant differences at any stage of follow up. In our study polyglyconate interference screw fixation for patellar tendon grafts has not found to be associated with increased clinical complications. It provided equivalent fixation and clinical results compared to metal screws.

[Antegrade flow in the aorta ascendens despite aortic atresia: 2 case reports with retrograde coronary perfusion through coronary fistulas and sinusoids]

In aortic atresia, coronary perfusion normally occurs through retrograde blood flow in the ascending aorta. We report on two patients with antegrade flow in the ascending aorta despite aortic atresia. In one patient with hypoplastic left heart syndrome (aortic atresia, severe mitral stenosis), an intact interatrial septum/premature closure of the foramen ovale was found. While no other way of left atrial or ventricular decompression was found, echocardiography, angiography and the post-mortem examination showed left ventricular to coronary sinusoids as the sole pathway for systemic oxygenation. In a second patient with complex congenital heart disease, including aortic atresia, antegrade flow in the ascending aorta was through a left coronary fistula with shunt flow originating from the pulmonary trunk. This report describes systemic perfusion depending on retrograde coronary flow due to coronary-cameral (sinusoids) and coronary arterio-venous fistulas leading to the phenomenon of antegrade blood flow in the ascending aorta despite aortic atresia.

Three-dimensional engineered heart tissue from neonatal rat cardiac myocytes

A technique is presented that allows neonatal rat cardiac myocytes to form spontaneously and coherently beating 3-dimensional engineered heart tissue (EHT) in vitro, either as a plane biconcaval matrix anchored at both sides on Velcro-coated silicone tubes or as a ring. Contractile activity was monitored in standard organ baths or continuously in a CO(2) incubator for up to 18 days (=26 days after casting). Long-term measurements showed an increase in force between days 8 and 18 after casting and stable forces thereafter. At day 10, the twitch amplitude (TA) of electrically paced EHTs (average length x width x thickness, 11 x 6 x 0.4 mm) was 0.51 mN at length of maximal force development (L(max)) and a maximally effective calcium concentration. EHTs showed typical features of neonatal rat heart: a positive force-length and a negative force-frequency relation, high sensitivity to calcium (EC(50) 0.24 mM), modest positive inotropic (increase in TA by 46%) and pronounced positive lusitropic effect of isoprenaline (decrease in twitch duration by 21%). Both effects of isoprenaline were sensitive to the muscarinic receptor agonist carbachol in a pertussis toxin-sensitive manner. Adenovirus-mediated gene transfer of beta-galactosidase into EHTs reached 100% efficiency. In summary, EHTs retain many of the physiological characteristics of rat cardiac tissue and allow efficient gene transfer with subsequent force measurement.

Chronic stretch of engineered heart tissue induces hypertrophy and functional improvement

To examine the influence of chronic mechanical stretch on functional behavior of cardiac myocytes, we reconstituted embryonic chick or neonatal rat cardiac myocytes to a 3-dimensional engineered heart tissue (EHT) by mixing freshly isolated cells with neutralized collagen I and culturing them between two Velcro-coated silicone tubes, held at a fixed distance with a metal spacer. After 4 days, EHTs were subjected to a phasic unidirectional stretch for 6 days in serum-containing medium. Compared to unstretched controls, RNA/DNA and protein/cell ratios increased by 100% and 50%, respectively. ANF mRNA and alpha-sarcomeric actin increased by 98% and 40%, respectively. Morphologically, stretched EHTs exhibited improved organization of cardiac myocytes into parallel arrays of rod-shaped cells, increased cell length and width, longer myofilaments, and increased mitochondrial density. Thus, stretch induced phenotypic changes, generally referred to as hypertrophy. Concomitantly, force of contraction was two- to fourfold higher both under basal conditions and after stimulation with calcium or the beta-adrenergic agonist isoprenaline. Contraction kinetics were accelerated with a 14-44% decrease in twitch duration under all those conditions. In summary, we have developed a new in vitro model that allows morphological, molecular, and functional consequences of stretch to be studied under defined conditions. The main finding was that stretch of EHTs induced cardiac myocyte hypertrophy, which was accompanied by marked improvement of contractile function.

Locked lateral patellar dislocation: a rare case of irreducible patellar dislocation requiring open reduction

Irreducible patellar dislocations are rare injuries, but those that do occur are mainly directed intra-articularly. In this case, a 53-year-old woman sustained a locked lateral patellar dislocation when falling from a chair. A preoperative CT-scan revealed bony avulsions at the insertion of the vastus medialis muscle, the medical retinaculum, and partial disruption of the ligamentum patellae from the apex patellae. Open reduction was necessary and the torn structures were reattached with anchor systems and sutures. Postoperative management included intensive physiotherapy. At 1 year after surgery, the patient was without swelling or pain and had a normal gait, but flexion was restricted to 120 degrees. All postoperative radiographs showed the patella correctly placed in the femoral groove.

[Early postoperative dysfunction of a modified Blalock-Taussig shunt: successful therapy with angioplasty and stent implantation in the subclavian artery]

A newborn with pulmonary atresia with ventricular septal defect and transposition of the great arteries was palliated with a modified Blalock-Taussig shunt at 5 days of age. Three days postoperatively arterial oxygen saturations dropped significantly. Thrombosis of the shunt was suspected. Angiography revealed stenosis of the proximal subclavian artery related to the creation of the shunt. The patient was successfully treated with angioplasty and stent implantation into the stenotic subclavian artery. Follow-up angiography 3 months after stent deployment showed a completely patent subclavian artery and unobstructed blood flow across the modified Blalock-Taussig shunt.

Conventional ventilation versus high-frequency oscillation: hemodynamic effects in newborn babies

OBJECTIVE

We conducted a prospective study to assess the hemodynamic effects of conventional mechanical ventilation (CMV) compared with high-frequency oscillation (HFO) in newborn babies with respiratory distress syndrome.

METHODS

A total of 18 consecutive term and preterm infants were examined by two-dimensional M-mode and pulsed Doppler echocardiography.

RESULTS

Five patients had to be excluded, three of them because of increasing cardiovascular support after initiation of HFO. The remaining 13 infants (seven males, six females) had a median gestational age of 33 wks (range, 25-40) and a birth weight of 2350 g (range, 790-3600). Patients entered the study at 21 hrs (range, 5-69) of life, receiving total maintenance fluid of 90 mL/kg/day (range, 60-120). Five babies (38%) needed continuous inotropic support. HFO was used as a rescue therapy in infants who failed with CMV. In all 13 patients, HFO significantly impaired cardiac performance compared with CMV by decreasing aortic velocity-time integral: median, 10.2 cm (range, 6.0-14.6) vs. 8.3 cm (range, 5.3-12.4; p<.002); stroke volume: median, 3.8 mL (range, 1.6-6.8) vs. 3.2 mL (range, 1.3-5.9; p<.002); and cardiac index: 281 mL/min/kg of body weight (range, 177-579) vs. 200 mL/min/kg of body weight (range, 156-591; p<.002). Fractional shortening was also significantly reduced: median, 0.31% (range, 0.24-0.44) vs. 0.29% (range, 0.20-0.34; p<.01), because of a significantly smaller left ventricular diastolic diameter during HFO: median, 1.4 cm (range, 1.0-1.9) vs. 1.4 cm (range, 0.9-1.8; p<.05), with a median difference of -0.07 cm (range, -0.4-0.2). HFO also causes a significant decrease in heart rate-corrected left ventricular ejection time: median, 0.25 sec (range, 0.23-0.28) vs. 0.23 sec (range, 0.21-0.26; p < .02) and heart rate-corrected velocity of circumferential fiber shortening (Vcfc): median, 1.3 circ/sec (range, 1.0-1.6) vs. 1.2 circ/sec (range, 0.9-1.4; p<.05). Left ventricular end-systolic wall stress (LVESWS; g/cm2) remained stable. The correlation between Vcfc and LVESWS did not show any significance (CMV, r2 = .2; HFO, r2 = .09). The regression line between Vcfc and LVESWS showed a higher y-intercept and steeper slope during CMV than during HFO. Heart rate, mean arterial pressure, and left ventricular systolic diameter remained unchanged.

CONCLUSIONS

In newborn babies, HFO significantly decreased left ventricular cardiac output caused by reduced left ventricular filling and HFO decreased contractility at higher mean airway pressures than with CMV.

A randomized trial comparing primary angioplasty with a strategy of short-acting thrombolysis and immediate planned rescue angioplasty in acute myocardial infarction: the PACT trial. PACT investigators. Plasminogen-activator Angioplasty Compatibility Trial

OBJECTIVES

The study evaluated the efficacy and safety of a short-acting reduced-dose fibrinolytic regimen to promote early infarct-related artery (IRA) patency during the inherent delay experienced by infarct patients referred for angioplasty as the principal recanalization modality.

BACKGROUND

Previous approaches using long-acting, full-dose thrombolytic infusions rarely showed benefit, but they did increase adverse event rates.

METHODS

Following aspirin and heparin, 606 patients were randomized to a 50-mg bolus of recombinant tissue-type plasminogen activator (rt-PA) (alpha half-life 4.5 min) or to placebo followed by immediate angiography with angioplasty if needed. The end points included patency rates on catheterization laboratory (cath lab) arrival, technical results when PTCA (percutaneous transluminal coronary angioplasty) was performed, complication rates, and left ventricular (LV) function by treatment assignment and time to restored patency following angioplasty.

RESULTS

Patency on cath lab arrival was 61% with rt-PA (28% Thrombolysis in Myocardial Infarction trial [TIMI]-2, 33% TIMI-3), and 34% with placebo (19% TIMI-2, 15% TIMI-3) (p = 0.001). Rescue and primary PTCA restored TIMI-3 in closed arteries equally (77%, 79%). No differences were observed in stroke or major bleeding. Left ventricular function was similar in both treatment groups, but convalescent ejection fraction (EF) was highest with a patent IRA (TIMI-3) on cath lab arrival (62.4%) or when produced by angioplasty within an hour of bolus (62.5%). However, in 88% of angioplasties, the delay exceeded 1 h: convalescent EF 57.3%.

CONCLUSIONS

Tailored thrombolytic regimens compatible with subsequent interventions lead to more frequent early recanalization (before cath arrival), which facilitates greater LV function preservation with no augmentation of adverse events.

Percutaneous transluminal angioplasty for the treatment of complete arterial occlusion after retrograde cardiac catheterization in infancy

Nine patients with arterial thrombosis were treated with transcatheter recanalization and subsequent balloon dilation of the occluded vessel. Repeat angiography or duplex sonography 3 to 14 months after intervention showed completely patent arteries without restenosis in 7 patients; there was residual narrowing of the vessel in the remaining 2 patients.

Galectins-1 and -3 and their ligands in tumor biology. Non-uniform properties in cell-surface presentation and modulation of adhesion to matrix glycoproteins for various tumor cell lines, in biodistribution of free and liposome-bound galectins and in their expression by breast and colorectal carcinomas with/without metastatic propensity

Protein (lectin)-carbohydrate (cellular glycoconjugate) recognition is operative in biochemical information transfer. Galectins constitute a family of endogenous galactoside-binding lectins with conserved features in the binding site. The members of this lectin category are assumed to be involved in cell adhesion and growth regulation. To assess to what extent the different modes of binding-site presentation and/or carbohydrate fine-specificities will affect aspects of galectin behavior, homodimeric cross-linking galectin-1 and monomeric chimeric galectin-3, with its collagenase-sensitive stalk linked to the carbohydrate-recognition domain, were investigated. Cell-surface expression of the two galectins and accessible galectin-binding sites on various tumor cell lines was ascertained by FACScan analysis. In particular, ligand accessibility for the two galectins differed for the tested cell line types. Binding of tumor cells to laminin and plasma or placental fibronectin was generally reduced by treatment of cells or matrix with galectins. Galectin-3 was more efficient than galectin 1 at impairing laminin's potency as matrix. Cell binding of galectin-1, on the other hand, proved on average more effective for blocking cell association to fibronectins after its preincubation with cell suspensions. Differences were also apparent in the biodistribution of the galectins, where an avian homolog of galectin- served as the control to distinguish effects of spatial and sugar-binding features. Histopathological analysis of lymph-node-negative and -positive breast and colorectal carcinomas (n = 180 including 60 metastatic lesions) indicated a correlation of either increased galectin-1 binding and reduced galectin-3 expression or reduced binding of both galectins with the occurrence of lymph node lesions. Together with data on the heparin-binding lectin, revealing reduced expression to be associated with a positive lymph-node status in the breast cancer group, these results can be interpreted to reflect cell-type-dependent requirements of galectin ligand presentation during the metastatic cascade. By introducing mammalian lectins to lectin-histochemical studies, the detection of quantitative differences in glycosylation brings an understanding of its cell biological significance one step closer.

Differential profile of facial injuries among mountainbikers compared with bicyclists

BACKGROUND

Bicyclists and mountainbikers are prone to facial trauma. In the current study, we present a large series of cycling-related sports trauma to the face in an effort to identify the injury pattern among mountainbikers compared with bicyclists.

METHODS

The medical records of a single pediatric and adult Level I trauma center were evaluated from January 1, 1991, through October 31, 1996. All admissions with injuries caused by cycling-related sports were reviewed, analyzed, and compared according to age and sex distributions, causes of accidents, injury types, frequency, and localization of fractures and associated injuries. The injury types were divided into three categories: fractures, dentoalveolar trauma, and soft-tissue injuries.

RESULTS

Five hundred sixty-two injured bicyclists (10.3% of all trauma patients) were registered at the Department of Oral and Maxillofacial Surgery, University of Innsbruck, Austria, during the study period, accounting for 31% of all sports-related or 48.4% of all traffic collisions, respectively. The review of the patient records revealed especially more severe injury profiles in 60 mountainbikers, with 55% facial bone fractures, 22% dentoalveolar trauma, and 23% soft-tissue injuries, compared with 502 street cyclists showing 50.8% dentoalveolar trauma, 34.5% facial bone fractures, and 14% soft-tissue lesions. The dominant fracture site in bicyclists was the zygoma (30.8%), whereas mountainbikers sustained an impressive 15.2% Le Fort I, II, and III fractures. Condyle fractures were more common in bicyclists, with 18.8% opposing 10.8% in mountainbikers.

CONCLUSION

Appropriate design of helmets with faceguards will reduce the incidence of facial injuries caused by cycling-related accidents and incentives are needed for making helmet use compulsory for all cyclists, particularly for mountainbikers.

Transcatheter recanalization and subsequent stent implantation for the treatment of early postoperative thrombosis of modified Blalock-Taussig shunts in two children

Two babies with duct-dependent cyanotic congenital heart disease were palliated with modified Blalock-Taussig shunts. One patient was diagnosed to have tetralogy of Fallot, and the other patient, tricuspid atresia type Ia. Early postoperative arterial oxygen saturations dropped significantly due to shunt thrombosis. Both patients were successfully treated with angioplasty and stent implantation.

Intracellular fluorescent probe concentrations by confocal microscopy

A general method is described that takes advantage of the optical sectioning properties of a confocal microscope to enable measurement of both absolute and relative concentrations of fluorescent molecules inside cells. For compartments within cells that are substantially larger than the point spread function, the fluorescence intensity is simply proportional to the concentration of the fluorophore. For small compartments, the fluorescence intensity is diluted by contributions from regions outside the compartment. Corrections for this dilution can be estimated via calibrations that are based on the intensity distribution found in a computationally synthesized model for a cell or organelle that has been blurred by convolution with the microscope point spread function. The method is illustrated with four test cases: estimation of intracellular concentration of a fluorescent calcium indicator; estimation of the relative distribution between the neurite and soma of a neuronal cell of the InsP3 receptor on the endoplasmic reticulum; estimation of the distribution of the bradykinin receptor along the surface of a neuronal cell; and relative distribution of a potentiometric dye between the mitochondria and cytosol as a means of assaying mitochondrial membrane potential.

[Interventional therapy for hemangioendothelioma of the liver in a newborn infant using a central venous approach]

We report on a newborn (birth weight 3600 g) with high-output cardiac failure due to a large hepatic hemangioendothelioma requiring mechanical ventilation. One day post-partum therapy with steroids, furosemide, and digitalis was initiated. Despite this, the clinical condition deteriorated. Therefore, selective coil-embolization of the arterial vessels supplying the hemangioendothelioma was performed using a venous approach with passage to the arterial side via the ductus arteriosus. After the embolization the patient improved quickly and he was extubated 4 days postinterventionally. Follow-up sonography 4 months postinterventionally showed dramatic regression of the hepatic tumor. We conclude that the coil-occlusion of hepatic hemangioendothelioma should be performed early in symptomatic newborns as arterial puncture and its associated complications can be avoided by using a venous approach with passage to the arterial side via the ductus arteriosus. In addition, in this age group, access to the portal system can be gained through the umbilical vein to occlude portal venous supplies to the hepatic hemangioendothelioma.

Intracellular fluorescent probe concentrations by confocal microscopy

A general method is described that takes advantage of the optical sectioning properties of a confocal microscope to enable measurement of both absolute and relative concentrations of fluorescent molecules inside cells. For compartments within cells that are substantially larger than the point spread function, the fluorescence intensity is simply proportional to the concentration of the fluorophore. For small compartments, the fluorescence intensity is diluted by contributions from regions outside the compartment. Corrections for this dilution can be estimated via calibrations that are based on the intensity distribution found in a computationally synthesized model for a cell or organelle that has been blurred by convolution with the microscope point spread function. The method is illustrated with four test cases: estimation of intracellular concentration of a fluorescent calcium indicator; estimation of the relative distribution between the neurite and soma of a neuronal cell of the InsP3 receptor on the endoplasmic reticulum; estimation of the distribution of the bradykinin receptor along the surface of a neuronal cell; and relative distribution of a potentiometric dye between the mitochondria and cytosol as a means of assaying mitochondrial membrane potential.

Transcatheter closure of atrial septal defects within the oval fossa: medium-term results in children using the 'ASDOS'-technique

OBJECTIVES

The purpose of this study was to evaluate the safety and efficacy of the ASDOS-technique (Sulzer-Osypka GmbH, Germany) for transcatheter closure of atrial septal defects within the oval fossa.

BACKGROUND

Although several attempts have been made to occlude defects within the oval fossa by transcatheter techniques, none of these has gained general acceptance.

METHODS

Patients with a defect in the oval fossa measuring equal to or less than 20 mm diameter, with a residual septal rim of 5 mm or greater, body weight greater than 10 kg, with clinical indications for surgical closure were considered for transcatheter closure. Follow-up investigations were performed at discharge, after 1, 3, 6 and 9 months, as well as after 1 and 2 years.

RESULTS

Of 78 patients considered for closure, a device was inserted in 41 patients (53%), with success being achieved in 40 patients (98%). The ages ranged from 1.1 to 15 years (7.8 +/- 1.92 years), the 'stretched' diameter of the defect from 10 to 20 mm (14.7 +/- 2.60 mm), and the diameters of the inserted devices from 25 to 45 mm (33.2 +/- 5.43 mm). Transient impairment of atrioventricular conduction occured in 4 patients. During the follow-up of 23.0 +/- 5.6 months elective surgical closure of a residual shunt was performed 26 months after insertion of the device in one patient. None of the other patients required surgery, hospitalisation or medical treatment, and none is requiring further treatment of the defect within the oval fossa. Fracture of one arm of the device occurred in 4 patients, but the fractured arms are in an unchanged and stable position after a period of at least 19 months.

CONCLUSIONS

Our medium-term data show that transcatheter closure in children of defects within the oval fossa can be performed with a high efficacy and safety using the ASDOS-device.

Disruption of the finger flexor pulley system in elite rock climbers

We treated 13 elite rock climbers for isolated disruptions of the pulleys of the long fingers. Diagnosis and treatment were based on the clinical finding of bow-stringing, which was confirmed by magnetic resonance imaging. Eight patients had bowstringing indicating incomplete disruption of the major pulley A2 and were treated nonoperatively (group A). Five patients showed bowstringing indicating complete disruption of the pulley A2. After failed nonoperative treatment, the pulleys were reconstructed (group B). The mechanism of injury and clinical and subjective results were evaluated. At a 31-month follow-up (range, 18 to 43 months), loss of extension in the proximal interphalangeal joint measured 5.6 degrees (range, 0 degree to 10 degrees) in group A and 4 degrees (range, 0 degree to 10 degrees) in group B. Circumference of the finger section was increased 4.2 mm in group A (range, 0 to 10 mm) and 4.8 mm in group B (range, 0 to 10 mm). Grip strength decreased 20 N in group A (range, 10 to 50 N) and 12 N in group B (range, 10 to 30 N). Four patients in group A and one in group B had bowstringing at clinical evaluation. On follow-up magnetic resonance images, bowstringing remained unchanged in group A but was reduced in all patients in group B. Good subjective results were seen in both groups.

[Acute compartment syndrome of the lower leg after ankle joint sprain. A case report]

In the field of traumatology, compartment syndromes of the lower extremity are often seen after fractures and direct injuries, or after ischaemia. Other causes include over-exertion and non-traumatic causes such as acute rhabdomyolysis, drug-induced myositis and eosinophilic myositis. This paper describes the clinical and MR course of a compartment syndrome following an ankle sprain.

Neoglycoproteins with the synthetic complex biantennary nonasaccharide or its alpha 2,3/alpha 2,6-sialylated derivatives: their preparation, assessment of their ligand properties for purified lectins, for tumor cells in vitro, and in tissue sections, and their biodistribution in tumor-bearing mice

Neoglycoproteins were prepared with chemoenzymatically synthesized complex biantennary N-glycan derivatives the nonreducing ends of which bear typical sequences found in glycoproteins. A chemically obtained biantennary heptasaccharide-azide was reduced and acylated with a 6-aminohexanoyl spacer. Elongation of the deprotected heptasaccharide using glycosyltransferases yielded a biantennary nonasaccharide with terminal galactose residues and two undecasaccharides terminating with alpha 2,6- or alpha 2,3-linked sialic acid. The free amino group of the spacer of these oligosaccharides was converted into an isothiocyanate. Its subsequent coupling to bovine serum albumin gave neoglycoproteins with a yield of 2.4-3.6 glycan chains per carrier molecule. This versatile synthetic pathway allows employment of a wide variety of complex-type glycans, which can be introduced to various test systems in vitro and in vivo to evaluate potential biomedical applications. Solid-phase assays with biotinylated sugar receptors revealed discriminatory binding properties of the three neoglycoproteins, especially for the mistletoe lectin. This direct assay system is preferable to the measurement of inhibitory capacities with respect to model ligands. Ligand type- and cell type-dependent quantitative differences in the binding properties of the probes were detected by FACScan analyses with a panel of tumor cell lines and by monitoring of staining in tissue sections for small cell and non-small-cell lung cancer and mesotheliomas. Biodistribution of iodinated neoglycoproteins in mice gave a prolonged presence of the sialylated probes in serum. Relative to the nonasaccharide, the uptake, especially of the iodinated neoglycoprotein with alpha 2,3-sialylated ligand chains, was clearly elevated in mice for kidneys and Ehrlich tumors. On the basis of the documented feasibility of these applications, it is concluded that the further elaboration of glycan chain variants by the described synthetic approach in combination with the given test panel is warranted to evaluate the potential of complex glycan chain-carrying neoglycoproteins for diagnostic and therapeutic purposes.

Changes in left ventricular function in shocked newborns

OBJECTIVE

To assess whether the change in cardiac output after volume replacement is due to elevation of stroke volume or heart rate and to determine the effect of mechanical ventilation on the hemodynamic situation.

DESIGN

Prospective study.

SETTING

A ten-bed neonatal intensive care unit (level III) at a university hospital.

PATIENTS

15 consecutive newborns with blood pressure below the 10th percentile related to age and weight.

INTERVENTIONS

Volume replacement with Ringer's lactate 20 ml/kg body weight.

MEASUREMENTS AND RESULTS

Before and after volume replacement, arterial pressure recordings, blood gas analysis, and an echocardiographic study were carried out. Left ventricular and aortic diameters were measured by the two-dimensional M-mode technique and velocity time integral of aortic flow by the pulsed color Doppler technique. From these data, stroke volume and cardiac output were calculated. Cardiac output (703 +/- 204 vs 826 +/- 166 ml/ min, p < 0.005) and cardiac index (267 +/- 69 vs 302 +/- 55 ml/min per kg body weight, p < 0.01) changed significantly due to an appreciable elevation in stroke volume (5.2 +/- 1.7 vs 5.8 +/- 1.7 ml, p < 0.05), whereas heart rate was unaltered (140 +/- 12 vs 142 +/- 20 beats/min; NS). The change in blood pressure (32 +/- 5 vs 38 +/- 8 mm Hg, p < 0.01) was also significant. Cardiac index before and after volume replacement showed a significant inverse correlation with the severity of respiratory disease expressed as alveolar-arterial oxygen difference (A-aDO2) (A-aDO2 vs cardiac index before volume replacement: r = -0.77, p < 0.001; after volume replacement: r = -0.73, p < 0.005) or oxygenation index (oxygenation index vs cardiac index before volume replacement: r = -0.73, p < 0.005; after volume replacement: r = -0.73, p < 0.005). Changes in left ventricular diastolic diameter, left ventricular systolic diameter, and fractional shortening were not significant.

CONCLUSIONS

These results indicate that the major regulator of left ventricular output in newborns with hypovolemic or cardiogenic shock is stroke volume and not heart rate and that cardiac output depends on the severity of the respiratory disease.

Three-dimensional reconstitution of embryonic cardiomyocytes in a collagen matrix: a new heart muscle model system

A method has been developed for culturing cardiac myocytes in a collagen matrix to produce a coherently contracting 3-dimensional model heart tissue that allows direct measurement of isometric contractile force. Embryonic chick cardiomyocytes were mixed with collagen solution and allowed to gel between two Velcro-coated glass tubes. During culture, the cardiomyocytes formed spontaneously beating cardiac myocyte-populated matrices (CMPMs) anchored at opposite ends to the Velcro-covered tubes through which they could be attached to a force measuring system. Immunohistochemistry and electron microscopy revealed a highly organized tissue-like structure of alpha-actin and alpha-tropomyosin-positive cardiac myocytes exhibiting typical cross-striation, sarcomeric myofilaments, intercalated discs, desmosomes, and tight junctions. Force measurements of paced or unpaced CMPMs were performed in organ baths after 6-11 days of cultivation and were stable for up to 24 h. Force increased with frequency between 0.8 and 2.0 Hz (positive "staircase"), increasing rest length (Starling mechanism), and increasing extracellular calcium. The utility of this system as a test bed for genetic manipulation was demonstrated by infecting the CMPMs with a recombinant beta-galactosidase-carrying adenovirus. Transduction efficiency increased from about 5% (MOI 0.1) to about 50% (MOI 100). CMPMs display more physiological characteristics of intact heart tissue than monolayer cultures. This approach, simpler and faster than generation of transgenic animals, should allow functional consequences of genetic or pharmacological manipulation of cardiomyocytes in vitro to be studied under highly controlled conditions.

[Long-term outcome of conservative or surgical therapy of anterior cruciate ligament rupture]

The treatment of anterior cruciate ligament (ACL) rupture continues to be a controversial subject. This study was undertaken to compare long-term results of different therapy regimens A total of 52 patients (mean age: 34.7 +/- 3.2 years) who underwent ACL reconstruction using the central one third of the patellar tendon and 32 patients (mean age: 38.3 +/- 5.2 years) treated conservatively were evaluated 5-7 years clinically, radiologically and with respect to their sports activities. In all, 25% of the patients operated on subjectively rated their knees as "excellent", 40.4% as "very good", 22.2% "good", 12.5% "fair" and 0% as "poor". The ratings for the conservatively treated group were: 12.9%, 19.4%, 29%, 25.8% and 12.5%, respectively. The results of the OAK score were significantly better for the surgically treated group (87.5 +/- 7.1 points compared with 77.1 +/- 13.4). An increasing number of degenerative changes were found on radiographs in both groups at follow-up as compared with their pre-injury status.

[Perilunate dislocation and dislocation fractures--results of surgical management]

We report 22 patients who sustained a perilunate dislocation (PD) with or without a fracture of the scaphoid. The carpal ligaments were explored and reattached in all cases. The fractured scaphoid in perilunate fracture dislocations (PFD) was stabilised by a Herbert screw in 13 cases and in one case with a Matti-Russe bone graft. After an average of 5 years the clinical score of Green and O'Brien showed good results for both PD and PFD. Patients with PFD had less pain and better grip than the patients with PD. The sagittal range of motion (average between 70 degrees and 99 degrees) and the subjective limitation in sports and work were equal for PD and PFD. The only open injury (PD) had the worst clinical result. All patients with PD showed a carpal instability dissociative of the proximal row (CID) and an arthrosis of the radiocarpal joint. In the patients with PFD a CID could be seen in 78% and an arthrosis in 93%. A carpal collapse occurred in 75% of cases after PD and in 29% after PFD. In 57% of cases the PFD was accompanied by a disruption of the SL ligament. The anatomical reconstruction of the scaphoid is essential for good carpal alignment. The stable fixation of bony avulsions showed good results. A CID could not be avoided in any of our patients with PD.