Challenges and Perspectives of Computerassisted Instruction in Medical Education

Objectives: In this paper we discuss solutions to the problem that medical teachers and students do not use modern computer-assisted instruction systems in medical education as much as expected by their developers.

Methods: As an example for a modern problem-based CAI system we introduce the CAMPUS shell system for case-based training in medicine.

Results: CAMPUS has received several awards and positive evaluation results. Nevertheless, the usage of such systems in courses and for self-study could be increased.

Conclusions: Curricular integration of CAI as well as further improvements on existing CAI systems to increase the usage in medical education is essential.

Corrective osteotomy of distal radial deformities: a new method of guided locking fixed screw positioning

Corrective osteotomy for distal radial malunion is a valuable but at times technically challenging operation. We have developed a new device to aid in the performance of the operation. We compared clinical use of the new technique with the standard technique. In 11 patients treated with the new technique the volar locking plate needed repositioning only once. With the standard technique in 17 patients the plate was repositioned in nine cases and needed bending in six cases. The new method corrected radial inclination (SD of 3° vs. 9°) and ulnar variance (SD of 0.9 mm vs. 1.4 mm) more predictably than the standard technique but there was no advantage in correction of volar tilt (SD of 6° vs. 4°). In our experience the new device makes corrective osteotomy of the distal radius easier and more reliable.

[A rare splenic involvement by Echinococcus multilocularis - case report]

In the present case an 81-year-old patient was operated upon for a suspected atraumatic spleen rupture. During the operation a spleen abscess was found. Histological examination of the removed spleen revealed an Echinococcus multilocularis infection. There was no sign of further organ involvement: surprisingly the liver was not affected. Case history, clinical outcome and the prescribed treatment are described. A short overview of the Echinococchus multilocularis syndrome is presented.

Challenges and perspectives of computer-assisted instruction in medical education: lessons learned from seven years of experience with the CAMPUS system

OBJECTIVES

In this paper we discuss solutions to the problem that medical teachers and students do not use modern computer-assisted instruction systems in medical education as much as expected by their developers.

METHODS

As an example for a modern problem-based CAI system we introduce the CAMPUS shell system for case-based training in medicine.

RESULTS

CAMPUS has received several awards and positive evaluation results. Nevertheless, the usage of such systems in courses and for self-study could be increased.

CONCLUSIONS

Curricular integration of CAI as well as further improvements on existing CAI systems to increase the usage in medical education is essential.

Integrin-linked kinase interacts with caspase-9 and -8 in an adhesion-dependent manner for promoting radiation-induced apoptosis in human leukemia cells

Integrin-mediated adhesion of leukemia cells to extracellular matrix proteins reduces apoptosis following radiation-induced genotoxic injury. To evaluate the role of integrin-linked kinase (ILK) in this process, HL60 human acute promyelocytic leukemia cells were stably transfected with ILK wild-type or kinase-hyperactive overexpression vectors. Suspension or fibronectin (FN) adhesion cultures were irradiated with X-rays and processed for measurement of apoptosis, mitochondrial transmembrane potential and caspase activation. Adhesion to FN pronouncedly reduced radiation-induced apoptosis of HL60 cells and vector controls. Intriguingly, overexpressed ILK enhanced apoptosis after irradiation by combined activation of caspase-3 through caspase-8 and -9 in irradiated FN cultures. Irradiation of ILK suspension cultures lacked caspase-8 activation, but showed serial cleavage of caspase-9, -3 and poly (ADP-ribose) polymerase. These findings further characterize the cell death-promoting function of ILK in DNA-damaged cells. Moreover, ILK might represent a potential therapeutic target for innovative chemo- and radiooncological approaches in hematological malignancies.

Transdiaphragmatic pleural lavage in penetrating thoracoabdominal trauma

BACKGROUND

The purpose of this study was to determine the incidence of thoracic sepsis following a systematic thoracic cavity washout through the injured diaphragm in patients with penetrating thoracoabdominal trauma.

METHODS

Prospectively collected data on all patients presenting with penetrating thoracoabdominal trauma between July 1999 and July 2002 were analysed. Patients with peritoneal biliary-gastroenteric (BGE) contamination and a diaphragmatic laceration were managed by laparotomy and transdiaphragmatic thoracic lavage.

RESULTS

A total of 217 patients had penetrating thoracoabdominal injuries, of whom 110 had BGE contamination of the peritoneal cavity with spillage into the pleural cavity. The mean Injury Severity Score was 38.1. Gunshot and stab wounds occurred in 79 (71.8 per cent) and 31 (28.2 per cent) respectively. Contamination was from the stomach (55.4 per cent), large bowel (37.3 per cent), small bowel (29.1 per cent), gallbladder and bile ducts (9.1 per cent) and pancreas (6.4 per cent). Thoracic complications occurred in six patients (5.5 per cent): empyema in two, Escherichia coli-related pneumonia in three and pleuritis in one. There were no deaths.

CONCLUSION

A thoracic washout through the injured diaphragm in patients with penetrating thoracoabdominal trauma and BGE contamination was associated with a low rate of intrathoracic septic complications.

Obstacle avoidance during human walking: H-reflex modulation during motor learning

The goal of this study was to investigate changes of H-reflex amplitudes during a motor learning task. Subjects with reduced vision were instructed to step over an obstacle on a treadmill as low as possible, while the soleus H-reflex was elicited. Acoustic warning and feedback signals about performance were provided. Performance improvement was associated with a decrease of muscle activity, needed to step over the obstacle (rectus femoris, biceps femoris, tibialis anterior and gastrocnemius medialis muscles), and of foot clearance, while joint angle trajectories from knee and ankle became more stable. The experiment consisted of five runs, three with normal treadmill walking and two with randomly stepping over the obstacle (100 times). H-reflexes were elicited at early and late stance phase before stepping over the obstacle. H/M ratio, latency and duration were determined. The values of these measures were calculated for the onset and end of a run and their course over time was evaluated using a correlation coefficient. The largest adaptations with a significant increase of reflex amplitude occurred during the first obstacle run. This increase lasted only briefly and the reflex amplitudes decreased to their previous values. During the later obstacle run, no H-reflex modulation occurred. It is concluded that a motor learning task causes adaptational effects not only on performance, but also on H-reflex responses. The results indicate that most of the modulation of H-reflexes is probably due to supraspinal influences on reflex transmission. The observations made are probably less specific for this motor task (stepping over the obstacle), but rather associated with the increased attention required by the motor learning task during the first obstacle run.

LDL-receptor-related proteins in Wnt signal transduction

The Wnt family of secreted signalling molecules are essential in embryo development and tumour formation. The Frizzled (Fz) family of serpentine receptors function as Wnt receptors, but how Fz proteins transduce signalling is not understood. In Drosophila, arrow phenocopies the wingless (DWnt-1) phenotype, and encodes a transmembrane protein that is homologous to two members of the mammalian low-density lipoprotein receptor (LDLR)-related protein (LRP) family, LRP5 and LRP6 (refs 12-15). Here we report that LRP6 functions as a co-receptor for Wnt signal transduction. In Xenopus embryos, LRP6 activated Wnt-Fz signalling, and induced Wnt responsive genes, dorsal axis duplication and neural crest formation. An LRP6 mutant lacking the carboxyl intracellular domain blocked signalling by Wnt or Wnt-Fz, but not by Dishevelled or beta-catenin, and inhibited neural crest development. The extracellular domain of LRP6 bound Wnt-1 and associated with Fz in a Wnt-dependent manner. Our results indicate that LRP6 may be a component of the Wnt receptor complex.

Sensitive ELISA dipstick test for the detection of chloroquine in urine under field conditions

OBJECTIVE

To evaluate a new enzyme-linked immunosorbent assay (ELISA) dipstick test for detecting chloroquine (CQ) in urine in a malaria-endemic region of north-western Namibia.

METHOD

Urine samples from 92 patients attending the outpatient department of Kamhaku Hospital with suspected malaria infection were tested for CQ with both the Dill-Glazko test and the ELISA dipstick test. Results were compared to the history of CQ intake as documented in the patients' health passes.

RESULTS

The dipstick test proved an easy-to-handle and very sensitive tool for the detection of CQ with a lower limit of detection at 120 nmol/l. It showed high agreement with the history of CQ intake within the last 6 months. The specificity in a negative control group was 100%. The Dill-Glazko test was far less sensitive and specific with a lower detection limit of 150 micromol/l.

CONCLUSION

The dipstick test can be used in pharmacological studies to evaluate the use of CQ, and as an inclusion criterion for in vivo and in vitro sensitivity tests, whereas the Dill-Glazko test is appropriate to test compliance during and a few days after CQ intake.

Pharmacology of kinins in the arterial and venous mesenteric bed of normal and B2 knockout transgenic mice

We have tested the vasoactive effects of kinins in addition to various other endothelium-dependent or independent agonists in the arterial and venous perfused mesenteric circuits of the mouse. Bradykinin (0.1 pmol-100 nmol), but not des-Arg9-bradykinin (10 nmol) induced a dose-dependent vasodilation of the precontracted arterial and venous mesenteric vasculature of the mouse. Furthermore, acetylcholine (2.5 nmol) also induced a marked arterial vasodilation but was without effect on the venous side. Other endothelium-dependent vasodilators, such as platelet-activating factor (PAF) (1 nmol), tachykinin NK1 selective agonist ([Sar9,Met(O2)(l1) ]substance P) (0.5 nmol) and adenosine diphosphate (5 nmol), were without effect on either side of the mesenteric bed of the mouse. The bradykinin B2 receptor selective antagonist (HOE 140) abolished the arterial and venous vasodilation induced by bradykinin without affecting that of acetylcholine or sodium nitroprusside. In addition, the bradykinin B1 receptor antagonist des-Arg9-[Leu8]bradykinin was without effect on the responses induced by bradykinin. A nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) markedly reduced, whereas removal of the endothelium with 3-[3-cholamidopropyl)dimethylammonio]-1-propane sulfonate (CHAPS) abolished dilatation to bradykinin and acetylcholine (arterial side only) without affecting that induced by sodium nitroprusside in the mouse arterial and venous mesenteric circuits. In the same two circuits of transgenic B2 knockout mice, the vasodilatory responses to bradykinin were absent, whereas the arterial circuit still responded to acetylcholine by a L-NAME-sensitive vasodilation. Our results suggest the exclusive contribution of B2 receptors located on the endothelium in the vasodilatory effects of bradykinin in the arterial and venous mesenteric circuits of the mouse.

Geographic differences in the sensitivity of a polymerase chain reaction for the detection of Plasmodium falciparum infection

The amplification of target DNA by highly specific probes using the polymerase chain reaction (PCR) provides a highly sensitive and specific method for the detection of malaria infection. The use the of PCR in settings with varying endemicity within one survey area has not been investigated intensively. Therefore, a cross-sectional study was conducted in the districts of Kabarole and Bundibugyo in western Uganda using material from three villages with different epidemiologic situations regarding malaria and DNA primers for a PCR that had shown satisfactory sensitivity and specificity in previous trials. The sensitivity of the PCR varied significantly (P < 0.001) in the three survey villages (between 63.2% and 83.9% for the primer pair K1-14-1 and between 37.9% and 69.9% for the primer pair MSP-1) and was highly linked to geographic differences and social exchanges of the inhabitants with other areas of the district. According to the results of this investigation, it is advisable not to use a single primer pair in epidemiologic field studies for the detection of falciparum malaria. The use of combined primer pairs and the frequent confirmation of the results by microscopy are recommended.

Salt-sensitive hypertension in bradykinin B2 receptor knockout mice

The kallikrein-kinin system regulates water and sodium excretion and thus plays a role in blood pressure (BP) homeostasis. We tested the hypothesis that mice lacking the gene encoding for the bradykinin B2 receptor (B2-KO) have a greater hypertensive response to chronic high Na+ intake (salt sensitivity) compared to controls. We also obtained dose-response curves for different vasoactive substances in both groups. The hypertensive effect of high Na+ intake was almost doubled in B2-KO mice compared to controls. A high-Na+ diet increased heart and kidney weight in B2-KO, but not in controls, suggesting an increased afterload in B2-KO mice. The BP response to bradykinin was completely abolished in B2-KO, but that to acetylcholine was conserved. The hypertensive response to angiotensin II was not exaggerated in B2-KO mice. This study describes a new salt-sensitive animal model and suggests that in mice kinins play a role in preventing salt-sensitive hypertension.

[Total skin electron beam irradiation in cutaneous T-cell lymphoma]

PURPOSE

Patients with cutaneous T-cell lymphoma are treated in Germany mostly by dermatological local therapy like corticosteroids or PUVA-irradiation. Total skin electron beam irradiation is used rarely, even though it has a potentially curative character. We present an analysis of patients, who received a total skin electron beam irradiation after having progressive disease following other treatment modalities.

PATIENTS AND METHODS

Twenty-one patients (mean age 58.9 years) in different stages were treated (stage IB and IIA n = 4, stage IIB n = 8, stage III n = 3, stage IV n = 6). All patients had progressive disease under other forms of local therapy. The irradiation was performed from 6 directions per hemibody using 2 axial fields which have each an 18 degree angle to the horizontal level. Six and 7 MeV fast electrons were used. Total dose was between 8 and 36 Gy in single dosis of 1 x 4 up to 5 x 2 Gy per week. In underdosed areas and areas of tumors of the skin boost irradiation with small fields was given.

RESULTS

All patients had a good tumor regression (complete remission: n = 10, partial remission: n = 11). With the follow-up between 4 and 93 months total- and recurrence-free survival was 18 and 7 months (median). Patients in early stages with slow but complete remission of the symptoms had the best prognosis. Because of the small case number there was no significant difference between the groups. There were no severe side effects of the radiotherapy noted.

CONCLUSION

Our analysis shows on a small patient number, that total skin electron beam irradiation has a good palliative effect on patients who have progressive disease following other types of treatment like PUVA or corticosteroids. The recurrence-free survival of 2 out of 4 patients with early stage disease (I-IIA) up to 93 month shows the potentially curative character of the treatment.

Stand-by treatment of suspected malaria in travellers

Travellers to malarious areas are increasingly advised to carry an emergency medication for self-treatment of suspected malaria in absence of medical attention. However, no data are available so far how travellers cope with self-diagnosis and stand by treatment (SBT). We therefore investigated the frequency, circumstances and outcome of emergency self-treatment for suspected malaria in German travellers. 3434 travellers were recruited for an open prospective study by 28 different travel clinics in Germany. 2867 travellers (90.1%) who returned questionnaires after their journey were analyzed. 40 travellers (1.4%) reported about SBT during their journey. Significant Plasmodium falciparum antibody levels could be demonstrated in only 4 of 37 SBT users (10.4%). In another 127 travellers with febrile episodes but without SBT use, no malaria was indicated by follow-up and/or serology.

Patency and morphology of fibrous polyurethane vascular prostheses implanted in the femoral artery of dogs after seeding with subcultivated endothelial cells

A cell culture line was established from enzymatically-derived canine jugular endothelial cells and further cultured. Whenever sufficient cells were present, fibrous polyurethane vascular prostheses, impregnated with gelatin and coated with fibronectin, were seeded with 4.8 x 10(5)/cm2 cells, sufficient to establish a confluent monolayer, and implanted in the femoral arteries of 16 dogs. A non-seeded prosthesis on the contralateral side served as control. Eight dogs received antiplatelet aggregation medication: 250 mg aspirin together with 25 mg dipyridamole, orally three times daily, starting 2 weeks prior to the implantation operation and continued for the duration of the experiment. Results show that in the non-medicated dogs all control prostheses become occluded within 3 weeks after implantation, whereas five out of eight seeded prostheses remained patent. In the medicated group, two out of eight control prostheses occluded and all seeded prostheses remained patent. Scanning and light microscopy revealed that seeded prostheses were completely lined with endothelial cells (Factor VIII positive stain) week 3 (n = 3) and 12 (n = 3) after implantation, while endothelialisation in control prostheses had advanced only 5 mm into the prostheses in 12 weeks. Two dogs of each group were included in long-term patency studies. We conclude that prostheses seeded with a confluent monolayer of endothelial cells result in superior patency rates for both medicated and non-medicated dogs. No immunological reaction against the (allogeneic) seeded endothelial cells were noted.

Development and long-term fate of a cellular lining in fibrous polyurethane vascular prostheses implanted in the dog carotid and femoral artery. A scanning and light microscopical study up to 53 months after implantation

The development and long-term fate of the inner cellular lining in 72 small caliber (3 mm inner diameter) fibrous polyurethane vascular prostheses explanted from dog carotid and/or femoral arteries at times ranging from 1.5 weeks up to 53 months after implantation were studied by scanning electron and light microscopy. A continuous cellular ingrowth from the vascular stumps into the 3 cm long prostheses was observed, which eventually resulted in a complete cellular lining 6 months after implantation. No other ways of endothelialization were noted. In fully endothelialized prostheses, the cellular ingrowth extended approximately 8 mm into the prostheses and consisted of several layers of fibroblasts and smooth muscle cells, covered by a very thin endothelioid cell layer. The newly developed lining was firmly anchored onto the inner prosthetic surface by means of cellular protrusions extended into the fibrous texture of the prosthetic wall. It was concluded that under experimental conditions in the dog complete endothelialization can be obtained in fibrous polyurethane vascular prostheses and that the lining remained thin and stable throughout the observation period of 53 months after implantation.

Seeding of enzymatically derived and subcultivated canine endothelial cells on fibrous polyurethane vascular prostheses

Fibrous polyurethane (FPU) prostheses with or without fibronectin coating and gelatin impregnation and FPU prostheses with or without fibronectin coating were seeded with 4.8 x 10(5) subcultivated dog endothelial cells per cm2 prosthesis. Expanded polytetrafluoroethylene (ePTFE) prostheses with and without fibronectin coating served as controls. The numbers of cells retained on uncoated polyurethane prostheses were minimal but increased with fibronectin coating and/or gelatin impregnation. Adhering cells were predominantly round in shape and few cells were seen stretched over the prosthetic fibres. Optimum numbers of cells were found in prostheses impregnated with gelatin and coated with fibronectin, where almost all the cells were stretched forming a confluent monolayer. In ePTFE prostheses only minimal numbers of cells were retained but in the fibronectin-coated prostheses a high cell count was noted. Gelatin-impregnated and fibronectin-coated FPU prostheses, as well as ePTFE prostheses coated with fibronectin, were additionally perfused in vitro after seeding under nearly physiological conditions for 1 h. Cells in the FPU prostheses were still present after perfusion, whereas all the cells in the ePTFE prostheses were lost from the inner surface. It is concluded that FPU prostheses impregnated with gelatin and coated with fibronectin are a suitable substrate for subcultivated endothelial cells to be seeded on. The cells remained at the surface even after 1 h in vitro perfusion with tissue culture medium under nearly physiological conditions. Further research including in vivo implantations is indicated.

Failure to obtain long-term patency after implantation of fibrous polyurethane prostheses in the carotid arteries of rabbits

Fibrous polyurethane prostheses were implanted in the carotid arteries and aortae of New Zealand white (NZW) and Chinchilla (CHIN) rabbits. No immediate post-implantation patency was obtained after implantation in the carotid arteries in NZW rabbits. In CHIN rabbits patency up to 1 week was obtained after carotid implantation. Attempts to increase patency rates by administration of 20 mg/kg body weight/day of both dipyridamol (DIP) and acetyl-salicylic acid (ASA) p.o., starting the week before implantation, had an adverse effect; prostheses became occluded within a few hours after implantation. Coagulation tests (Lee and White, Am J Med Sci 145:495-503, 1913) carried out with blood drawn from CHIN rabbits revealed hypercoaguability after administration of either 10 or 20 mg/kg body weight/day of both DIP and ASA compared to pre-medication values. Prostheses implanted in the aortae of both strains remained patent without anti-platelet-aggregation therapy for a 3-month observation period. It is concluded that in the NZW rabbit carotid implantation was not successful due to severe spasmic reactions and that in CHIN rabbits only very short-term patency could be obtained both with and without administration of 10 or 20 mg/kg body weight/day medication DIP and ASA.

[The pathogenic effect of human immunodeficiency virus. Molecular biological results]

Recent data suggest that the pathogenicity of HIV is mediated by the production of metabolised viral components which act as hormones. In particular the replication and maturation of T-lymphocytes, and the cellular interaction of immunocompetent cells and nerve cells are affected. The recognition of HIV by the immune system and consequently also the progression of the disease, is influenced by the HLA-type (DR-1) of the infected person. Replication of HIV may be accelerated by the simultaneous presence of other viruses (i.e. cytomegalovirus). So-called apathogenic, attenuated HIV variants have been described.

Auxiliary liver transplantation in jaundiced rats with UDP-glucuronyltransferase deficiency and defective hepatobiliary transport

In this study auxiliary liver transplantation (ALT) has been tested as a means of correcting the UDP-glucuronyltransferase deficiency in Gunn rats and the UDP-glucuronyltransferase deficiency and impaired hepatobiliary bilirubin transport in double mutant rats. In both groups serum bilirubin normalized and remained low until the end of the study at 12 weeks after transplantation in 4 out of 6 rats. Excretion of 99mTc-HIDA in non-transplanted double mutants was considerably slower than in Gunn rats (kel 0.9 x 10(-3) versus 4.3 x 10(-3) s-1). HIDA excretion by transplants in double mutants and Gunn rats was about equal (kel 1.6 x 10(-3) and 1.1 x 10(-3) s-1). Experiments with bile duct-cannulated transplants showed that in double mutants bile flow, bile acid and bilirubin excretion was 2-4 times higher than in Gunn rats. This study shows that auxiliary liver transplants can conjugate and excrete bilirubin when one of these or both functions are lacking in the recipient's liver.

Neointima formation in expanded polytetrafluoroethylene vascular grafts with different fibril lengths following implantation in the rat aorta

Expanded polytetrafluoroethylene (PTFE) prostheses with fibril lengths of 30 and 60 microns were implanted in the rat infrarenal aorta. Sequential scanning electron and light microscopic studies of the prostheses after implantation demonstrated a different pattern of endothelialization. Prostheses with a fibril length of 60 microns had a continuous multilayered neointima at week 25 postimplantation, whereas prostheses with a 30-microns fibril length had a discontinuous and single layer of endothelium after the same interval. It was concluded, therefore, that a prerequisite for the development of a lining in a vascular prosthesis is for the inner surface of the prosthesis to have adequate pores for effective anchoring of the invading endothelioid cells. Expanded PTFE prostheses with an internodular distance of 60 microns provided sufficient anchoring possibilities for invading endothelioid cells to form a continuous neointima.

Implantation of 20 cm long polyurethane vascular prostheses in the femoral artery of dogs. Preliminary results

In a preliminary experiment externally reinforced polyurethane prostheses measuring 20 cm in length, with an inner diameter of 3 mm, were implanted in a loop in the femoral artery of six dogs. The dogs received 250 mg acetylsalicylic acid and 25 mg dipyridamol three times a day as anti-thrombocyte aggregation therapy starting three weeks prior to surgery. Anti-thrombocyte aggregation therapy was continued throughout the study. All prostheses remained patent 8, 9, 15 and 17 months after implantation. Patency was confirmed by palpation and Doppler ultrasound measurements. Preliminary results suggest that in clinically relevant situations, these prostheses could function well over prolonged periods of time.

Patency rate of small caliber fibrous polyurethane vascular prostheses implanted in the dog carotid and femoral artery improved by use of acetylsalicylic acid and dipyridamol

Segments of 3 mm diameter fibrous polyurethane vascular prosthesis of length 3-4 cm were prepared. They were bilaterally implanted in the carotid and femoral arteries of male and female beagles. Four groups consisting of animals receiving either no medication or thrombocyte aggregation drugs were studied: Group A (8 dogs), no medication: group B (19 dogs), 500 mg acetylsalicylic acid (ASA) once daily and 25 mg dipyridamol (DIP) three times daily orally for 6 weeks after the implantation operation; group C (14 dogs), 250 mg ASA and 25 mg DIP three times daily orally for 6 weeks after the implantation operation; group D (12 dogs), 250 mg ASA and 25 mg DIP three times daily orally for 25 weeks after the implantation operation. Medication was started one week prior to the implantation operation. In group A, all prostheses were occluded at week 6. There was a significant difference in patency rates between groups B-D and C-D. No significant differences in patency rates could be found between groups B and C. The best patency rates were obtained 25 weeks after implantation in group D for both the right and left carotid and right and left femoral implantation sites. Highest patency rates were observed when ASA and DIP were given for 25 weeks.

Augmentation by L-dopa of growth inhibition and melanin formation of X-irradiated Harding-Passey melanoma cells in culture

Treatment of exponentially proliferating melanogenic Harding-Passey melanoma cells in monolayer culture (HPM-73 line) with a single dose of X-irradiation (up to 8 Gy) or continuously (for several weeks) with L-3,4-dihydroxyphenylalanine (L-Dopa) up to 5 X 10(-4) M resulted in a dose-dependent inhibition of cell proliferation, but not in death of all cells. Actually, 8 Gy-irradiated or L-Dopa (2 X 10(-4) M)-treated cultures finally reached the cell number and cell density of controls. However, a combination of a single dose of radiation (8 Gy) followed by L-Dopa (2 X 10(-4) M)-treatment resulted in destruction of all cells. Melanin formation was stimulated by L-dopa-treatment or X-irradiation, and was further elevated by the combined application of radiation and L-Dopa-exposure. Whether the effects of exogenously applied L-Dopa, an intermediary metabolite of melanin synthesis, are due to the conversion to growth-inhibitory metabolites (quinones, radicals, etc.) inside or outside the cell, was discussed. The latter might result from release (due to membrane damage or cell disintegration) of tyrosinase or/and melanosomes into the culture medium with the consequence of extracellular synthesis of potentially cytotoxic metabolites from medium substrates. Further, endocytosis of exogenous melanosomes and tyrosinase with potentially harmful effects is feasible. An application of such a combination therapy of melanoma to clinical medicine should be considered.

Endothelialization of polyurethane vascular prostheses implanted in the dog carotid and femoral artery

A new type of vascular prosthesis made of polyurethane with a fibrous structure of the wall was implanted in the carotid and/or femoral artery of dogs. The healing process and neo-intima formation after implantation of this type of prosthesis was followed with light- and scanning electron microscopy. A total of 18 prostheses, which had been implanted for 1, 3, 6, 9 or 20 weeks were studied. Endothelial like cells invaded the prosthesis over the anastomoses, starting the first week after implantation. The growth zones advanced steadily, and prostheses measuring 3 cm in length were completely endothelialized by 20 weeks after implantation, a mean growth rate of the endothelial like cells of 0.09 mm/day. Subsequently, fibroblasts and smooth muscle cells grew between the neoendothelial layer and the prosthetic inner surface, forming a new multi-layered neo-intima. Cellular elements of the neo-intima were firmly anchored onto the inner wall of the prosthesis by cells with extending cytoplasmic protrusions between the fibers of the prosthetic wall. Since in this type of fibrous polyurethane prosthesis, endothelial like cells continually grew until a new lining was formed, apparently facilitated by the fibrous structure of the wall, further investigations are indicated for progression toward clinical implantation of this type of prosthesis.

[Success and long-term results of radiotherapy of periarthritis humeroscapularis]

The results in 164 patients receiving radiotherapy for humeroscapular periarthritis were evaluated on the basis of questionnaires. In all, 76% of the patients reported an improvement. A long-term study over an average of 5 years showed 61 patients (49%) to have experienced long-lasting freedom from pain. However, 38 patients (24%) noticed no improvement. Criteria affecting the success of therapy seem to include the length of the history of the disease as well as inadequate differential diagnosis. No influence is attributed to age, sex or previous types of treatment.

The formation of a neo-intima in textile prostheses implanted in the aorta of rats and dogs

The formation of a neo-intima in textile prostheses implanted in the rat and dog aorta was studied by means of light- and scanning electron microscopy. Two independent cellular layers (the superficial and deep ingrowth layers) developed on the free surface and under the fibrin layer initially deposited on the inner surface of the prostheses. The superficial ingrowth layer invades the prosthesis from both the proximal and distal aortic stumps and extends over the primary fibrin layer, or replaces it. This layer consists mainly of smooth muscle cells of the triangular aortic type covered by endothelial-like cells. The deep ingrowth layer originates from cellular elements of the prosthetic bed. Fibroblasts, myofibroblasts and spindle-shaped smooth muscle cells invade the fibrin layer through the interstices of the fabric structure of the prosthesis. Precursors of endothelial cells, however, are absent from this population. The superficial and the deep ingrowth layers may become joined by progressive replacement of the fibrin layer, but remain distinguishable because of their different cellular components. When a continuous cellular layer is established on the inner surface of the prosthesis, and this is then covered by endothelial-like cells, the neo-intima formed remains stable during long-term studies.

[Effect of neuraminidase and x-rays (2 Gy and 8 Gy) on microvilli and membrane invaginations of Ehrlich ascites tumor cells in monolayer culture]

A monolayer culture (Eagle basal medium plus 10% of fetal calf serum) of Ehrlich ascites tumor cells was exposed to X-radiation with 2 Gy and 8 Gy and treated with Vibrio cholerae neuraminidase alone or combined with sublethal X-ray irradiation (2 Gy). Pictures of the Ehrlich ascites tumor cells taken with the electron microscope were investigated in order to find out any cell surface modifications due to membrane invaginations and microvilli. The results showed that the rate of microvilli as well as that of membrane invaginations became higher with the increasing X-ray dose (2 Gy; 8 Gy). Following to neuraminidase treatment there was a considerable augmentation of membrane invaginations as compared to control cells, whereas the number of microvilli was slightly reduced. As it has been already described before, the influence of neuraminidase produced an increased endocytosis activity and a strengthening of the cytoskeleton. Combined treatment with neuraminidase and sublethal X-radiation (2 Gy) caused a higher rate of membrane invaginations than each method alone; the number of microvilli was slightly increased by combined treatment. The conclusion is drawn that these structure modifications are due to reparation processes induced by radiation on the one hand and to an enzymic action of neuraminidase on the cell surface on the other hand.

Determination of the patency of vascular prostheses implanted in the rat aorta by means of ultrasonic blood-flow measurements

Patency of vascular prostheses implanted in the rat aorta is usually confirmed by reoperation and inspection of the distal stump of the aorta for pulsations. Repeated reoperation on rats included in long-term investigations is not possible because of the increasing formation of scar tissue and adhesions at the site of the distal aorta. Consequently, noninvasive ultrasonic Doppler measurement was investigated to determine whether this method could provide accurate information about the patency of an implanted prosthesis. A total of 37 rats with 10-cm-long prostheses implanted in the aorta (groups C nonsupported prostheses, n = 12; and D supported prostheses, n = 25), eight normal nonoperated controls (group A), and three rats with a ligated aorta (negative controls, group B) were studied over a period of 12 weeks. The Dopplerrecordings obtained in the normal animals served as controls for the recordings of rats with an implanted prosthesis. A prosthesis was considered patent if the Dopplermeasurements obtained from the femoral artery resembled that of the normal pattern. In seven cases a prosthesis was suspected to be occluded since the Dopplermeasurements resembled those obtained after aortic ligation. Autopsy confirmed the Dopplermeasurements in all cases. No Dopplermeasurements returned to normal in the femoral artery in the aorta-ligated rats even after longer periods post-operation. It is concluded that Dopplermeasurements can accurately provide information about the patency of a vascular prosthesis implanted in the rat aorta.

Amsacrine-associated cardiotoxicity: an analysis of 82 cases

Amsacrine is an antileukemia drug being widely used in North America, Europe, Australia, and New Zealand. In the initial clinical trials, patients treated with amsacrine developed occasional instances of acute cardiac arrhythmias and cardiomyopathy. We review and analyze the features of cardiac abnormalities associated with amsacrine in 82 patients, 27 of whom have not been previously reported. The rest have been reported in the literature, but we have included a large amount of additional information about these patients in our analysis. We conclude that amsacrine-related cardiac events are less common than those related to anthracycline chemotherapeutic agents. Manifestations of such toxicity include ECG abnormalities, ventricular and atrial arrhythmias, sudden death, and congestive heart failure. There is little or no cumulative dose effect. Hypokalemia may be a risk factor for development of serious tachyarrhythmias, but such problems can occur despite a normal serum potassium level. Amsacrine appears to affect depolarization and repolarization of the heart, but the mechanism is unknown.

The inner prosthetic surface structure and re-endothelialization: an experimental study in the rat using two types of microvascular prostheses for aortic implantation

Two types of microvascular prostheses were implanted in the rat infrarenal aorta. Operations were carried out with clean, nonsterile instruments under ether anesthesia. Anastomoses were made with a continuous 8-0 suture. In group A, a 1-cm-long piece of expanded polytetrafluorethylene (PTFE) and in group B a 1-cm-long fibrous polyurethane prosthesis were implanted. Both groups consisted of 18 rats. Three rats from each group were killed at days 3, 5, 10, 20, 40, and 60 postimplantation. Prostheses were examined by scanning electron and light microscopy for the re-endothelialization. All prostheses in both groups were patent at the time of death. Re-endothelialization started in both types of prostheses the fifth day after implantation and had advanced 1-3 mm in the PTFE prostheses at day 60. However, in the fibrous polyurethane prostheses, re-endothelialization progressed and a complete new lining was achieved between days 20 and 40 postimplantation. The endothelium/neointima in the fibrous prosthesis was firmly anchored onto the prosthetic wall by means of cellular protrusions between the polyurethane fibers. In contrast to this observation, the endothelium/neointima developed in the PTFE prostheses was not anchored to the wall of the prosthesis. It is emphasized that the development of a new lining in a prosthesis may reduce the risk of endogenous, hematogenous infections. From the results of this study, we have concluded that there is a correlation between the inner surface structure and the extent of the re-endothelialization of a prosthesis. A prosthesis with a fibrous structure is much more rapidly and completely re-endothelialized than an expanded PTFE prosthesis.

History of (micro) vascular surgery and the development of small-caliber blood vessel prostheses (with some notes on patency rates and re-endothelialization)

The historical development of vascular surgery is reviewed from ancient times (Ruphus of Ephesus, Aëtius of Amida) to recent developments (sutured anastomosis by Carrel). Attempts to anastomose blood vessels by means of nonsuturing technique, using a ring or short tube of diverse materials called prostheses, were undertaken at the start of this century and continued until shortly after World War II. With the advent of modern polymeric materials, prostheses of different types, sizes, structures, and fabrics have been used to substitute for blood vessels, both experimentally and clinically. Recently, blood vessel prostheses with small (1-1.5 mm) internal diameters became available and have been implanted experimentally. Patency rates, biophysical and structural properties, the re-endothelialization and the neointima formation of several types of microvascular prostheses are briefly reviewed.

Three years experience with experimental implantation of fibrous polyurethane microvascular prostheses in the rat aorta

The results of a 3-year study in which a series of 355 implantations of 1-cm-long fibrous polyurethane microvascular prostheses into the infrarenal aorta of the rat (group A) were evaluated with respect to patency and formation, structure, and fate of the neo-intima. Rats were sacrificed at various intervals from 1 day to 2 years in order to obtain a time-related impression of the re-endothelialization and stability of the neo-intima. A second series of 51 implants was done with prostheses 10 cm in length, placed in a 1.5-cm loop in the abdominal aorta (group B). An overall patency rate of 92.7% was achieved in group A. Initially, eight technical failures caused early thrombosis of the prostheses. Sixteen prostheses became infected and subsequently occluded. The overall patency in group B was 52.9%, due to kinking from adhesion formation and normal growth of the rat. In both the long and short prostheses, a continuous multilayered neo-intima developed, growing from the aortic stumps into the prosthesis from both sides. According to the growth rate of 0.3 mm/day, a 1-cm prosthesis was re-endothelialized after +/- 20 days and a 10-cm prosthesis after +/- 9 months. Once developed, the neo-intima, consisting of myofibroblasts and smooth muscle cells covered with a flat endothelium, remained stable and continuous, throughout the observation period. The neo-intima was firmly anchored onto the prosthetic wall by means of cellular protrusions extending between the polyurethane fibres. The significance of rapid healing of an implanted prosthesis is emphasized with respect to preventing (late) hematogenous, endogenous infection of the prosthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Validation of liquid chromatographic method for assay of chlorthalidone in tablet formulations

A stability-indicating, reverse phase liquid chromatographic (LC) method was developed for assay of chlorthalidone in tablet formulations. The chromatographic system separates the parent compound from its potential hydrolysis product (4'-chloro-3'-sulfamoyl-2-benzophenone carboxylic acid), which can be quantitated at low levels, and another degradation product (2-chloro-5-(1-methoxy-3-oxo-1-isoindolinyl)benzenesulfonamide), which was found during the experimental work. The procedure can also be used for content uniformity determinations. The general utility of the method was demonstrated by the assay of several product brands. The validated procedure was shown to be accurate, precise, reproducible, and specific.

Patency and neo-intima development in 10 cm-long microvascular polyurethane prostheses implanted into the rat aorta

Microvascular fibrous polyurethane prostheses (inner diameter 1.5 mm, length 10 cm) were implanted in the abdominal aorta of rats. The prostheses were fixed in a loop. All rats (n = 37) were reoperated 6 weeks after implantation to verify the patency of the prostheses. Eight prostheses were obliterated from various causes. The remaining 29 prostheses were found to be patent 3 months after implantation, which gives a patency rate of 79%. Six weeks and 3 months after implantation 7 and 4 rats, respectively, with patent prostheses were sacrificed. The remaining 18 rats of this study are still alive, more than 4 months after implantation, and will be included in long-term observation studies. The prostheses were examined using both light and scanning electron microscopy. The patent prostheses exhibited macroscopically a clear and transparent inner surface. No obliterative processes could be found either macroscopically or microscopically. Neo-intima ingrowth had advanced +/- 10 mm into the prostheses over the anastomotic line from both ends 3 months after implantation, and was continued by a single endothelium layer for several centimeters. An acellular, stable fibrin film was found inbetween the cellular lining. The neo-intima was anchored at the prosthesis by cellular protrusions extending between the polyurethane fibers. Though 10 cm long prostheses were implanted under unfavorable hemodynamic conditions, a patency rate of 79% was achieved, both 6 weeks and 3 months after implantation. This patency rate could have been higher if evident technical failures had been avoided.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of removal of serum from the culture medium and sublethal roentgen irradiation on microvilli and invaginations of the cell membrane of Ehrlich ascites tumor cells in monolayer cultures]

In order to find out modifications of microvilli and invaginations, the cellular surfaces of Ehrlich ascites tumor cells in monolayer culture (basal medium of Eagle + 10% fetal calf serum) were investigated with the aid of electron-microscopic cross-sections. The tumor cells had been cultured without serum 24 hours prior to investigation or irradiated with 2 Gy. Morphometric evaluation after cell culture in a serum-free medium showed a reduced number ob microvilli and a diminution of sections of microvilli. As already described before, a reduction of cell proliferation, of the microtubule-microfilament system, and of the endocytosis activity occurs under these serum-free conditions. The number of invaginations (related to a constant membrane part) was reduced by nearly 50% after serum extraction. Similarly to serum extraction, sublethal X-ray irradiation reduced the sections of microvilli, whereas the number of microvilli increased slightly. Contrary to the effect of serum extraction, the irradiated cells showed twice as many invaginations as the non-irradiated control cells. These differences in the surface structures are interpreted as a result of modified growth stimulations (+/- serum) and radiogenic reparation processes.

Significance of the inner-surface structure of small-caliber prosthetic blood vessels in relation to the development, presence, and fate of a neo-intima. A morphological evaluation

Microvascular prostheses with three different inner surface structures were examined morphologically 1-18 months after implantation to evaluate the presence and structure of the neo-intima. Fibrous polyurethane tubes (length: 5-10 mm, inner diameter: 1.5 mm) were implanted in the rat abdominal aorta in group A with a fibrillar inner structure (pore sizes 20-50 microns), and in group B the inner fibrillar structure was coated with an impermeable continuous silicon sheet. Expanded polytetrafluorethylene vascular prostheses (length: 40 mm, inner diameter: 4 mm) were implanted in the dog carotid artery (group C). The specimens were examined by light microscopy and scanning electron microscopy. A continuous and permanent neointima was only found in the prostheses with the porous fibrillar inner structure (group A). The thin new lining sheet was well attached to the prosthetic wall by cellular protrusions. In the silicon-coated prostheses (group B) also a continuous neo-intima had developed which, however, was irregular, thicker, and not anchored to the prosthetic wall. The expanded polytetrafluorethylene prostheses (group C) showed also after 1 year only incomplete lining with a neo-intima. Fresh blood cell deposits could be observed in the unlined prosthetic wall. It is concluded that a continuous lining of vascular grafts with a thin neo-intima is only achieved if the cells invading the prostheses from the anastomotic areas can anchor their cytoplasmic protrusions onto an appropriately structured inner surface. If these anchoring facilities are not provided, the unattached neo-intima will thicken, interfering with the patency of these microvascular prostheses, or fragments of the neo-intima or alternatively mural thrombi may constantly strip off and embolize.

Fast Continuous Swimming of Saithe (Pollachius Virens): a Dynamic Analysis of Bending Moments and Muscle Power

This paper deals with the hydrodynamics and internal dynamics of fish swimming. Our analysis starts from kinematic data obtained for fast swimming saithe, and treats the fish as a flexible elongated body. The distribution along the body of the lateral bending moment and the bending power generated inside the fish are computed as well as the power spent on the water. The computed thrust implies a drag coefficient (based on wetted surface area) of about 0.007, which is probably an over-estimate. Our major result is that the bending moment does not travel as a running wave from head to tail like the lateral body curvature does, but behaves as a standing wave. The left and right sides produce alternate contractions simultaneously over the whole body length. This finding is in agreement with myographic data from the literature.

A fibrous polyurethane microvascular prosthesis. Morphological evaluation of the neo-intima

A fibrous polyurethane microvascular prosthesis with an inner diameter of 1.5 mm was implanted to replace the rat aorta between the left renal artery and the bifurcation of the aorta. Twenty-four implantations, using three different lengths (0.5; 1; 1.5 cm), were carried out. Rats were sacrificed 3, 6, 9 and 12 weeks after implantation. Only 1 prosthesis was occluded (probably due to a technical error). Grafts were already lined with a neo-intima by the third week, irrespective of their length. Different shapes of endothelial cells were recognized. It appeared that cells arise and migrate from the aortic stumps into the prosthesis, since the neo-intima is thicker in the anastomotic area than in the middle of the graft. The well-defined neo-intima consisted of several layers of smooth muscle cells embedded in a glycoprotein matrix and covered by a very flat continuous endothelium. The structure of the prosthesis allowed anchoring of the lining cells. Migration of cells through the wall of the prosthesis was not observed. At those places in the prosthesis where fibres had fused together to form flat areas the neo-intima became torn by the contraction of the myofibroblasts. This was because the cells had evidently failed to become anchored to the prosthetic wall. The neo-intima retained the ability of immediate repair of small defects which develop occasionally on the non-fibrous areas of the luminal surface of the prosthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

The endothelialization process of a fibrous polyurethane microvascular prosthesis after implantation in the abdominal aorta of the rat. A scanning electron microscopic study

The endothelialization process of a fibrous microvascular polyurethane prosthesis (inner diameter 1.6 mm) was studied by scanning electron microscopy. Forty-seven prostheses (1 cm) were implanted into the abdominal aorta of rats between the left renal artery and the bifurcation. Specimens were taken on day 1, 3, 5, 7, 10, 14, 18, 21 and 25, as well as 6 and 9 months after implantation, to evaluate immediate and delayed response and complications. The patency rate of the implants was 91.2%. After an initial recovery period of five days, endothelial cells started to migrate onto the inner surface of the prosthesis with a velocity of approximately 0.3 mm per day, resulting in a completely endothelialized prosthesis at day 21. A smooth continuous inner lining was achieved. A difference in growth pattern between the proximal and distal growth zone was observed, and may be attributed to the direction of the blood flow through the prosthesis. The endothelial cells advanced in a close arrangement. No cells were seen to settle and grow in between the two growth zones on the fibrin layer. If no immediate complications occur, the endothelialization process (21 days) proceeds uneventfully and no late complications are observed. Though it may be argued that the new cells lack some authentic endothelial features, this study indicates that they are at least of endothelial orgin, and behave morphologically like endothelial cells. It can be concluded that the adequate texture of the prosthesis and the cell anchoring, in combination with both an optimal surgical performance and blood flow, ensure that the microvascular prostheses are rapidly endothelialized and retain high patency rates over long periods of time.(ABSTRACT TRUNCATED AT 250 WORDS)

[Ultrastructural studies on the effect of roentgen rays and quinacrine (atebrin)--alone or in combination--on Ehrlich ascites tumor cells in monolayer culture]

Already two days after an X-ray irradiation with 8 Gy performed during the phase of exponential growth, the cells of an Ehrlich ascitic carcinoma in monolayer culture showed remarkable ultrastructural modifications, e.g. a markedly vacuolized endoplasmic reticulum, swollen mitochondria, increase of lysosome-like structures, and a decrease of microvilli in number and size. Ehrlich ascitic carcinoma cells submitted to an X-ray irradiation with 8 Gy and subsequently incubated with quinacrine (Atebrin) in a concentration of 4 x 10(-6) M, which alone had no significant effects on growth or ultrastructure, showed severe cellular lesions. The endoplasmic reticulum was still more vacuolized, the mitochondria were severely damaged, lysosome-like structures and residual bodies were increased, and the cellular surfaces had still less microvilli. Microtubules and microfilaments, however, seemed rather increased. The effects of quinacrine (Atebrin) on cells exposed to X-rays were discussed with respect to the known inhibiting action of this substance on DNA synthesis, especially with regard to DNA reparation. The modifications of the microtubule-microfilament system could be correlated to increased intracellular digestive processes involved in the catabolism of radiodamaged structures.

[Radiotherapy of cervix and uterus carcinomas (Marburg results of 1960 to 1975)]

The authors present the therapy results and complications of 479 patients with carcinomas of the cervix and 241 patients with carcinomas of the body of the uterus. The five-year survival rate of the patients with carcinomas of the cervix is 57%. The first five years after diagnosis were survived by 79.6% of the patients in stage I, 57.3% of the patients in stage II, 31.1% of the patients in stage III, and 5.9% of the patients in stage IV. 60% of these patients were only submitted to percutaneous and intracavitary irradiation, and 40% were irradiated after operation. The five-year survival rate of the patients with carcinoma of the body was 74.3%. This rate was 80.8% in stage I, 77.5% in stage II, 57.5% in stage III, and 30% in stage IV. The operation frequency was relatively high with 74%, only 26% of these patients were only treated by radiotherapy. The percutaneous radiotherapy was performed exclusively under high voltage conditions, preponderantly according to the method of Marburg which allows a homogenous, small-field irradiation of the small pelvis with a dose until 45 Gy, but which deliberately does not expose to radiation the para-aortal lymph nodes. In the years of 1966 to 1971, a comparison with the method established in Düsseldorf was made. This method is working with two big U-shaped stationary fields including the para-aortal lymph nodes. The central part of the pelvis is collimated when percutaneous irradiation is applied, and the intracavitary treatment is applied with a higher dose, correspondingly. The present analysis of the treatment results of both methods does not show any significant difference as to the survival time. The incidence of fistulas, however, a severe late complication, which is 2.4% for the method of Marburg, is markedly lower than that of 8.6% for the other method. Prognostic factors and therapeutic aspects are discussed in detail.