Type 2 T-Cell Responses against Distinct Epitopes of the Desmoglein 3 Ectodomain in Pemphigus Vulgaris

Pemphigus vulgaris (PV) is an autoimmune blistering disorder of the skin and/or mucous membranes caused by IgG autoantibodies that predominantly target two transmembrane desmosomal cadherins: desmoglein (DSG)1 and DSG3. DSG-specific T cells play a central role in PV pathogenesis because they provide help to autoreactive B cells for autoantibody production. In this study, we characterized DSG3-specific peripheral T cells in a cohort of 52 patients with PV and 41 healthy controls with regard to cytokine profile and epitope specificity. By ELISpot analysis, type 2 T cells reactive with the DSG3 ectodomain were significantly increased in patients with PV compared with those in healthy controls. By dextramer analysis, CD4+ T cells specific for an epitope within the extracellular domain of DSG3, DSG3(206-220), were found at significantly higher frequencies in patients with PV than in HLA-matched healthy controls. T-cell recognition of two distinct DSG3 epitopes, that is, DSG3(206-220) and DSG3(378-392), correlated significantly, suggesting a synergistic effect in B-cell help. Immunization of HLA-DRB1∗04:02-transgenic mice with PV with the same set of DSG3 peptides induced pathogenic DSG3-specific IgG antibodies, which induced loss of keratinocyte adhesion in vitro. Thus, DSG3 peptide-specific T cells are of particular interest as surrogate markers of disease activity and potential therapeutic targets in PV.

GLOS and HARM in patients with transient neurovascular symptoms with and without ischemic infarction

BACKGROUND AND PURPOSE

Gadolinium leakage in ocular structures (GLOS) on fluid attenuated inversion recovery images (FLAIR) is a novel imaging marker in acute ischemic stroke and other neurological disorders.

METHODS

In patients with transient neurovascular symptoms who underwent repeated MRI with intravenous contrast agent administration, the presence of acute ischemic lesions on diffusion-weighted images (DWI) as well as the frequency and pattern of blood-brain barrier and blood-retina barrier impairment as demonstrated by the hyperintense acute reperfusion marker (HARM) and GLOS respectively on postcontrast FLAIR were evaluated.

RESULTS

Overall 28 patients with transient neurovascular symptoms (median age 70.5 years; 18 (64.3%) male) were included. Follow-up MRI was performed within 35 (IQR 21-47) hours after the initial MRI. On DWI, acute ischemic lesions were observed in 22 (78.6%). On contrast-enhanced FLAIR, GLOS was observed in 12 (42.9%) patients: in 1 (3.6%) only in the anterior chamber, and in 11 (39.3%) in the anterior chamber and vitreous body. HARM was observed in 3 (10.7%) patients. In one patient without ischemic lesion on DWI or HARM on FLAIR, GLOS was observed in the anterior chamber and vitreous body. Presence of GLOS was associated with higher age (p = 0.04) and detection of HARM (p = 0.03).

CONCLUSIONS

In patients with transient neurovascular symptoms, GLOS is a frequent finding and associated with HARM on contrast-enhanced FLAIR. As GLOS was observed in one patient without an ischemic lesion or HARM, it might be useful as an additional imaging marker.

Wirksamkeit von Doxycyclin bei Chlamydiosen in Taubenbeständen

Gegenstand und Ziel: Untersuchung der klinischen Wirksamkeit von über das Trinkwasser verabreichtem Doxycyclin zur Behandlung der Chlamydiose bei Briefund Rassetauben (Columba livia f. domestica) in infizierten, klinisch erkrankten Beständen unter Praxisbedingungen. Material und Methoden: Im Rahmen einer kontrollierten Feldstudie zur klinischen Wirksamkeit wurden 13 Taubenbestände mit klinisch manifester Ornithose über 25 Tage mit einer neuartigen Formulierung von Doxycyclin über das Trinkwasser behandelt. In jedem der Bestände war die Infektion mit Chlamydia psittaci zuvor anhand molekularbiologischer Untersuchung von Organmaterial zur pathologischen Untersuchung eingesandter Tiere festgestellt worden. Zur Überprüfung des Therapieerfolgs wurden am 25. Tag der Behandlung und 7 Tage nach Abschluss der Therapie Dreifachtupfer von 10 Tieren jedes Bestandes genommen und mittels PCR untersucht. Ferner fanden wiederholt Einzeltier- und täglich Herdenuntersuchungen in den Beständen statt. Ergebnisse: Der Erreger Chlamydia psittaci sowie andere, in sechs der 13 Bestände zusätzlich dokumentierte atypische Chlamydienspezies ließen sich bei den genannten Untersuchungen nicht mehr nachweisen. Zudem wurde in jedem Bestand ein Verschwinden der klinischen Krankheitssymptomatik erreicht. Schlussfolgerung: Die Anwendung von Doxycyclin im beschriebenen Therapieregime erwies sich als wirksam zur Behandlung der Ornithose. Darüber hinaus konnte eine hervorragende Akzeptanz und Verträglichkeit der eingesetzten Formulierung in praxi bestätigt werden.

VNUS Closure radiofrequency ablation of varicose veins

Endovenous procedures are increasingly being used to eliminate epifascial variose veins. The radiofrequency therapies VNUS Closure and VNUS Closure FAST Catheter have established themselves and boast very good results compared to other endovenous procedures with regard to closure rates and postoperative quality of life. Equipment and method: Between February 2005 and December 2009, a total of 2413 patients comprising 3366 great and small saphenous veins were operated upon at the Vascular and Venous Diseases Department of DERMATOLOGIKUM HAMBURG. 2241 great and small saphenous veins were treated with the VNUS Closure FAST catheter, 1125 great and small saphenous veins were treated with the Closure PLUS catheter system. Additionally, 264 recurrent varicose veins were treated with the Closure FAST system. Ultrasound examinations were conducted 7 days after the treatment, again 6 weeks after the treatment, and at the follow-up examination one year after treatment. Any recanalisations were treated immediately. Between January 2007 and January 2009, 57 patients were also treated for perforant veins between stages C-4 and C-6. Gender and age distributions, as well as CEAP classifications corresponded to standard distributions. Compression stockings were only administered in the case of advanced chronic venous insufficiency (C-4 to C-6). The patients were anticoagulated before treatment by means of a low molecular weight heparin as a single shot prophylactic. Anticoagulation through thrombocyte aggregation inhibitors or dicumarin was continued. Results: 1089 great and small saphenous veins were examined after removal with Closure PLUS radiofrequency therapy. The primary closure rate after 6 weeks was 98.9%; after one year, 91.2%; after two years 99.0%; after three years, 98.2%; and after four years, 100%. 2241 great and small saphenous veins were treated with the VNUS Closure FAST Radiofrequency System. 2096 great and small saphenous veins were examined after treatment. The primary closure rate after 7 days was 99.7%; after 6 weeks, 99.6%; after one year, 98.8%; and after two years, 100%. The rate of minor complications after Closure FAST Radiofrequency catheter treatment of the great saphenous vein was 5.3%; after treatment of the small saphenous vein, 5.9% in total. No major complications – such as deep vein thromboses or pulmonary embolisms – were caused, and neither was burning of the skin. The closure rate one week after RFS treatment was 84.6%; after 6 weeks, 86.2%; and after one year, 78.3%. In all of the recurring varicose veins, the recirculation was successfully eliminated. Conclusion: The VNUS Closure FAST Radiofrequency catheter represents a standardised, established procedure for treating epifascial varicose veins to ensure the certain elimination of recirculation. The development of Closure PLUS 6-French and 8-French catheter into Closure FAST Radiofrequency catheter has led not only to a reduced operation duration but also a safe and high closure rate after follow-up. With the new concept of segmental ablation the Closure FAST system eliminates the catheter pullback variability and standardises and simplifies the procedure. The success of the treatment is shown by the complete decomposition of the vein underneath the inflow of the superficial epigastric vein or the inflow of the gastrocnemic veins. However, the long term results for the Closure FAST system are awaited eagerly. The current high closure rates and high patient satisfaction rates give us cause to look ahead with hope.

Hippocampal infarction: Identification of three new types

BACKGROUND AND PURPOSE

Hippocampal infarction (HI) is common but yet still not comprehensively studied. In the present study, we aimed to identify novel HI patterns and to describe additional ischemic lesions outside the hippocampus to draw conclusions regarding the underlying vessel occlusion.

METHODS

In 222 patients (mean age 69.9 (±13.6) years; 129 (58.1%) male, 93 (41.9%) female) with HI, diffusion-weighted images were analyzed with emphasis on HI patterns and associated ischemic lesions outside the hippocampus. HI were classified as type 1 (complete), 2 (lateral), 3 (dorsal), and 4 (circumscribed). Further possible HI patterns were defined and classified as type 5 (ventral), 6 (ventrolateral), and 7 (dorsolateral).

RESULTS

Unilateral HI was found in 218 (98.2%) patients. In these, type 5 and 6 were identified in 5 (2.3%) patients, and type 7 in 8 (3.7%) patients respectively. Type 1 was found in 62 (28.4%), 2 in 53 (24.3%), 3 in 57 (26.1%), and 4 in 28 (12.8%) patients. Further ischemic lesions were found in the territory of the anterior cerebral artery (3.6%), middle cerebral artery (14.9%), anterior choroidal artery (AChA) (7.2%), posterior cerebral artery (89.6%), and in the brainstem (6.3%) and cerebellum (20.3%). Type 5 and 6 were significantly associated with acute ischemic lesions in the AChA territory (6/10 (60%) vs. 11/200 (5.5%), P<0.001).

CONCLUSIONS

We identified three novel HI types. Probably, type 5 and 6 can be attributed to occlusion of the AChA. Overall, these HI types are rare, possibly due to a better collateralization in the case of AChA occlusion.

Isolated punctuate hippocampal infarction and transient global amnesia are indistinguishable by means of MRI

Background Small punctuate lesions in the hippocampus on diffusion-weighted images are a typical finding in transient global amnesia. Consequently, it has been suggested that diffusion-weighted images findings might corroborate the diagnosis of transient global amnesia. However, isolated punctuate hippocampal infarction might be a differential diagnosis of transient global amnesia. Aim Evaluation of isolated punctuate hippocampal infarction frequency and comparison of its clinical presentation and MRI findings to transient global amnesia. Methods From an MRI database, we identified 10 patients with isolated punctuate hippocampal infarction and compared these to 12 patients with transient global amnesia with diffusion-weighted images lesion with regard to clinical symptoms and MRI findings. Results Disorientation and memory deficits were more common in transient global amnesia patients, whereas dysphasia/aphasia and vertigo were more common in hippocampal infarction patients. MRI findings in isolated punctuate hippocampal infarction and transient global amnesia did not differ significantly, neither regarding the affected hemisphere, lesion distribution, size, nor relative ADC values. Conclusions Differentiation of isolated punctuate hippocampal infarction and transient global amnesia based on neuroimaging findings is not possible. Thus, in the case of isolated punctuate hippocampal diffusion-weighted images lesions the final diagnosis of hippocampal infarction or transient global amnesia should be based on the clinical presentation.

[Potential for intervention of private health insurers in discharge management using the example of stroke patients]

The study reveals that stroke patients today can still experience gaps in the provision of healthcare and fragmented therapy. This is often the case on transferral from the inpatient to outpatient sector, causing complications that could be avoided by means of good discharge management across all sectors. Private health insurance can actively support and positively influence the treatment process in the form of case management. Individual contact with stroke patients and their relatives allows for early planning and organisation of the next steps, and offers patients the support they need during a difficult phase of life.

Lateral compression type B 2-1 pelvic ring fractures in young patients do not require surgery

PURPOSE

According to Young and Burgess, type B 2-1 pelvic fractures are a type of lateral compression fracture (LC-1) and are the most common pelvic injury at all ages. Although they are considered unstable in rotation and despite biomechanical recommendations for anterior stabilization, most authors recommend non-operative treatment. However, studies comparing outcomes and complications regarding operative versus non-operative treatment are still scarce.

METHODS

Seventy-one patients aged under 65 years with a type B 2-1 pelvic fracture were treated between 2006 and 2011. Patients in Group I (n = 35) were treated non-operatively and patients in Group II (n = 36) were treated operatively. Postoperative complications, clinical course, and follow-up (VAS for Pain, SF 36, EQ-5D) of at least 1 year postoperatively were evaluated.

RESULTS

Our data show that operatively treated patients had a significantly higher complication rate. Preoperatively, the only significant difference between the non-operative and operative groups was the amount of anterior fracture dislocation and the presence of an isolated pelvic ring fracture. In the postoperative follow-up, no significant differences were found regarding pain or quality of life.

CONCLUSION

Type B 2-1 pelvic ring fractures in young patients should be treated non-operatively.

[Cutaneous infection with Aggregatibacter actinomycetemcomitans]

BACKGROUND

Aggregatibacter actinomycetemcomitans is a small, gram-negative, non-motile, coccobacillus. Aggregatibacter actinomycetemcomitans is known to cause periodontal disease and to be associated with actinomycosis.

CASE REPORT

We report a patient developed a chronic wound following trauma about the right heel. The lesion resolved after oral antibiotic therapy with cefpodoxime und surgical debridement. Bacterial cultures grew abundant Aggregatibacter actinomycetemcomitans, but no actinomyces species.

OBJECTIVE

The importance of Aggregatibacter actinomycetemcomitans in chronic wounds needs to be explored.

[Polytrauma with pelvic fractures and severe thoracic trauma: does the timing of definitive pelvic fracture stabilization affect the clinical course?]

BACKGROUND

The aim of this study was to investigate the influence of the surgical timing in patients with pelvic fractures and severe chest trauma on the clinical course, especially on postoperative lung function.

METHODS

A total of 47 patients were included in a prospective dual observational study. The study investigated the clinical course depending on the time of operation based on the functional lung parameters, SAPS II, SOFA and total hospital stay.

RESULTS

The average ISS was 32±6, PTS was 34±11 and TTSS was 9±3 points. The pelvic fractures were stabilized definitively after an average of 7±2 days. The early stabilization correlated significantly with a lower TTSS and SAPS II on admission (p<0.05), shorter time of ventilation (p<0.05) and stay in the intensive care unit (p<0.01) as well as the decreased need for packed red blood cells (p<0.01).

CONCLUSIONS

In this study patients with pelvic fractures and thoracic trauma benefited positively from an earlier definitive pelvic fracture stabilization with respect to a shorter time of ventilation and stay in the intensive care unit due to a lower need for red cell concentrates.

[Efficacy of doxycycline for treatment of chlamydiosis in flocks of racing and fancy pigeons]

OBJECTIVE

Evaluation of the clinical efficacy of doxycycline application via drinking water in the treatment of chlamydiosis in infected, clinically ill flocks of racing and fancy pigeons (Columba livia f. domestica) under field conditions.

MATERIAL AND METHODS

In the scope of a field study, 13 pigeon flocks with clinically manifest ornithosis were treated over a period of 25 days with a novel doxycycline formulation via drinking water. Infection with Chlamydia psittaci had been confirmed beforehand by molecular-biological investigation of organ material from dissected pigeons in each flock. Therapeutic success was evaluated by PCR-analysis of triple swabs from 10 animals of each flock on day 25 of treatment and 7 days after completion of the therapy, as well as by repeated individual and daily herd examination.

RESULTS

The causative agent Chlamydia psittaci together with additionally documented atypical chlamydia species in six of the 13 flocks could thereby no longer be detected. Furthermore, a resolution of clinical symptoms was achieved in each of the treated pigeon flocks.

CONCLUSION

Application of doxycycline in the described therapy regimen proved successful for the treatment of ornithosis. In addition, excellent acceptance and tolerance of the deployed formulation could be confirmed in praxis.

Clinical implementation of finite element models in pelvic ring surgery for prediction of implant behavior: a case report

BACKGROUND

Osteosyntheses to stabilize pelvic-ring fractures were developed for younger patients, and are not universally indicated for elderly people. We present the results of parallel-arranged numerical simulations of fixation treatment that an elderly patient with a bagatelle-injured pelvic ring fracture received using a patient-specific finite element model.

METHODS

The clinical course of an osteosynthetic stabilized pelvic ring fracture, based on an actual case, was numerically simulated using a patient-specific finite element model.

FINDINGS

A previously validated finite element model of a human pelvis was customized with computed tomography data from a patient with a stabilized pelvic-ring fracture. Numerical simulation was used to analyze primary stability. The clinical process, represented by radiologic examinations, was compared with the results from the finite element simulation. Implant loosening as well as newly-occurring fractures were shown to coincide with regions with the highest stress levels.

INTERPRETATION

The results from the patient-specific finite element model closely resembled the actual clinical course especially in terms of the location of high strain concentration and subsequent implant loosening. This indicates that patient-specific finite element models have a potential to play an important role in planning osteosynthesis according to biomechanical stability.

[Influence of routine CT examination on fracture classification and therapy for pelvic ring fractures in patients aged over 65 years old]

BACKGROUND

The incidence of pelvic ring fractures in elderly patients increases continuously. Several studies showed that the complexity of injury is often underestimated and a fracture of the posterior pelvic ring not visible with conventional X-rays. The aim of this study was to determine the influence of routine CT on incidence, classification of and therapy for pelvic ring fractures in patients aged over 65 years.

PATIENTS AND METHODS

Between 2004 and 2010, 310 elderly patients with a pelvic ring fracture were admitted to a German university level 1 trauma centre. Patients of group 1 (2004-2006) were examined with CT only if a pelvic ring fracture was diagnosed by X-ray and pain in the posterior pelvic ring persisted so that mobilisation was impossible. In group 2 (2007-2010) CT was used for routine examination. Demographic data, injury mechanism and severity (ISS) were documented as well as time and type of diagnostic procedure. Also fracture classification (AO), time and type of treatment were investigated in correlation with total hospital stay.

RESULTS

252 (82 %) patients were female, the median age was 81 years (65-100 years). 228 (74 %) had a low energy trauma, 41 (13 %) a traffic accident and 12 (4 %) had fallen from heights over 3 m. Only in 29 (9 %) cases was no trauma evident. 35 (11 %) patients were injured with an ISS over 16 and classified as polytrauma. The mean ISS was 26.8 ± 11.7. In group 2 the incidence of type A fractures decreased from 64 % to 36 %, whereas the incidence of type B fractures increased from 25 % to 49 % as did isolated sacrum fractures from 1 % to 6 %. Also the indication for operative stabilisation changed in type B fractures from 33 % to 40 % and in isolated sacrum fractures to 71 %. Total hospital stay was between eight and ten days in non-operative and between 20 and 22 days in operative treatment.

CONCLUSION

A low energy trauma is the major cause of injury for patients of an age over 65 years with a pelvic ring fracture. With the routine CT examination type B fractures and isolated sacrum fractures are seen more often than expected and resulting in a change of treatment procedures.

Description of the iliolumbar ligament for computer-assisted reconstruction

STUDY DESIGN

The iliolumbar ligament (IL) was examined using morphometric and virtual methods.

OBJECTIVES

A macroscopic study was performed to measure the anterior (AIL) and the posterior part of the IL (PIL).

SUMMARY OF BACKGROUND DATA

Though being a widely accepted cause of low back pain and lumbosacral instability, the IL is neglected in computer-based biomechanical studies due to the lack of morphometric information.

METHODS

Frozen sections prepared from 29 human subjects were measured and 7-tesla MR images made to distinguish the AIL and PIL. Cuboids were designated as geometric figures to both parts of the ligament, allowing computer-based calculations of length, surface, volume and angle of positional relationships.

RESULTS

Based on 7-tesla MR imaging, virtual reconstruction was conducted for one male pelvis, including the IL. While left- and right-side parameters varied at a statistically significant level, no gender-dependencies could be determined. Lengths of 30 and 25 mm were measured for the AIL and PIL, as well as heights of 17-19 mm, respectively, and a thickness of 4mm.

CONCLUSIONS

Correlations between the side-dependent parameters and the AIL and the PIL of the same side indicate close functional relationships. Additional dependencies suggest that the IL is capable of compensating age-related as well as bone-attributed alterations in lumbosacral morphology. The IL data and the visualised ligament structures contribute to determination of the influence of the IL in spinal and sacroiliac stability by means of computer-assisted biomechanics.

[Fatal risk thrombosis? A prospective study for the incidence of deep vein thrombosis in pelvic fractures]

AIM

The aim of the study was to determine the incidence of deep vein thrombosis (DVT) after pelvic trauma and surgical stabilisation of pelvic and acetabular fractures under medicamentous prophylaxis.

PATIENTS AND METHOD

Within 20 months we prospectively included 50 patients. 25 had an isolated pelvic trauma, 25 patients had multiple injuries. 21 of them were polytrauma patients (average ISS: 31.4; min. 26 pts., max. 50 pts.), four patients had additional highly unstable spine fractures or fractures of the lower extremities. Low molecular-weight heparin (Enoxaparin 40 g/d) was administered on average within 24 hours of injury in 44 cases, one patient received low-dose heparin (Liquemin 15,000 to 22,500 I. E./d), five patients received both. 31 patients were treated operatively and 19 conservatively. Colour-flow duplex ultrasonography was performed within 72 hours of injury and stabilisation of the pelvic and acetabular fracture, or weekly. By means of ultrasound, 97 to 100 % of the deep and superficial leg veins could be examinated safely, as well as 88 to 89 % of the external iliac veins and 64 to 66 % of the common iliac veins. Only in 36 to 40 % of the patients the internal iliac veins were visible by ultrasound.

RESULTS

Proximal DVTs were detected postoperatively in two patients (4 %), one patient (2 %) died after a fatal P. E. before the scheduled duplex scan.

CONCLUSION

Early medicamentous prophylaxis can prevent deep vein thrombosis after pelvic trauma. Delayed applications due to pelvic operations are risk factors. In such cases duplex scanning should be performed routinely and postoperative medicamentous prophylaxis should be increased.

Genomic hybridization of bovine class II major histocompatibility genes: 1. Extensive polymorphism of DQ alpha and DQ beta genes

Class II genes of the bovine major histocompatibility complex (MHC) were investigated by Southern blot analysis using human cDNA probes for DQ alpha, DQ beta, DR alpha and DR beta. The presence of a DQ-like and a DR-like subregion in cattle was clearly indicated. Highly polymorphic restriction fragment patterns were obtained when genomic DNA, digested with any one of the BamHI, EcoRI or PvuII restriction enzymes, was hybridized with the DQ alpha and the DQ beta probe. The polymorphisms were interpreted genetically by analysing five paternal half-sib families of the Swedish Red and White breed. The material comprised, besides the bulls, 28 offspring and their dams. The analysis resolved 9 and 12 allelic variants of DQ alpha and DQ beta respectively. Thus, this investigation establishes a method for routine typing of MHC class II gene polymorphism in cattle. The results were entirely consistent with close linkage of DQ alpha and DQ beta since no recombinant was found and since alleles at these loci occurred in complete linkage disequilibrium in the material investigated. Close linkage between DQ and the blood group locus M, which has previously been found to be closely linked to the serologically defined BoLA-A locus, was also indicated. In this study DNA was isolated from frozen semen samples of dead bulls, which shows that this type of analysis will be useful in genetic investigations in cattle breeds, where artificial insemination is practised.

Genomic hybridization of bovine class II major histocompatibility genes: 2. Polymorphism of DR genes and linkage disequilibrium in the DQ-DR region

Class II genes of the bovine major histocompatibility complex have been investigated by Southern blot analysis using human cDNA probes for DQ alpha, DQ beta, DR alpha and DR beta. In this report restriction fragment length polymorphisms of DR alpha and DR beta are described. The polymorphisms were interpreted genetically by analysing five paternal half-sib families of the Swedish Red and White Breed, comprising altogether 28 offspring. Using the restriction enzymes BamHI, EcoRI and PvuII, three DR alpha and three DR beta allelic fragment patterns were resolved. The DR alpha and DR beta genes thus appear to be much less polymorphic than the previously described DQ alpha and DQ beta genes. Also, the observed linkage disequilibrium between DR genes was less pronounced than that between DQ genes, whereas the association between DR and DQ haplotypes was very strong. The family data available indicated strongly that the DQ alpha, DQ beta, DR alpha and DR beta genes are all closely linked.

Anwendung der Beckenzwinge beim polytraumatisierten Patienten mit instabilem Becken

BACKGROUND

Unstable fractures of the posterior pelvic ring are frequently combined with severe hemorrhage. In 80% of cases the bleeding originates in the ruptured presacral venous plexus or the fracture itself. Arterial bleeding is less common. The pelvic clamp introduced by Ganz can make it possible to stabilise the pelvis, with subsequent compression of the fracture planes and reduction of the intrapelvic volume in such cases, so improving the prognosis. Use of the pelvic clamp can be integrated into the management in the emergency room with no problem.

METHODS

This paper presents the authors' own modification of the technique for using the pelvic clamp in the emergency situation when only a clinical examination of the patient has been possible and also analyses specific problems that arise in this situation. To this end, the data relating to 29 polytraumatised patients with unstable posterior pelvic ring fractures were analysed in a retrospective study.

RESULTS

In all, 8 complications were seen in 6 patients. There were 2 cases of pin malposition and 2 of over-compression of the ossa coxae and local wound problems. Secondary pin dislocation was observed in 1 case. In all these cases it was possible to correct the pelvic clamp, so that emergency stabilisation was practicable without further surgical intervention. Minor complications were found in 2 patients. These took the form of bleeding at the pin-insertion site. In 1 case an unstable transiliacal fracture was found, and in this case it was not possible to stabilise the posterior pelvic ring with the pelvic clamp. No iatrogenic lesions were detected following application of the pelvic clamp.

CONCLUSION

In the hands of an experienced and practised user application of the pelvic clamp is a safe method for emergency stabilisation of the posterior pelvic ring in polytraumatised patients, even without blood volume control. Problems can be solved and do not generally mean the pelvic clamp cannot be used. The immediate radiological check (e.g. during the emergency CT -scan performed for primary diagnosis) is a must, however.

Phase I trial of docetaxel, oxaliplatin and capecitabine (TEX) in patients with metastatic gastric cancer

14051

Background: Combination regimens of 3 active drugs have shown promising activity in treatment of metastatic gastric cancer (GC). Docetaxel (D) combined with cisplatin and 5-FU (CF) yielded superior overall survival and response rates when compared to standard CF. However, toxicity profile showed the need for development of less toxic modifications. In this phase I trial, D was combined with oxaliplatin (Ox) and capecitabine (Cape) in order to define the maximum tolerated dose (MTD) and dose-limiting toxicities (DLT) in patients (pts) with metastatic GC. Methods: Pts had to have metastatic or locally advanced GC, adequate organ function, ECOG PS 0–2, no prior chemotherapy. Four dose levels were planned planned for the TEX regimen: D 35–40 mg/m2, Ox 70 mg/m2 d1 and d88, with Cape 800–1000 mg/m2 bid d1–14 q d22. Toxicity was assessed 3-weekly whereas CT scans were repeated 9-weekly. Results: 14 pts were enrolled: 9m/5f, age 64 (42–76) yrs, ECOG PS 1 [0–2]. All pts. had distant metastatis, 10 no gastrectomy. On dose level 1 (D 35 mg/m2, Ox 70 mg/m2, Cape 800 mg/m2) 3 pts were included initially. 1 pt. had grade 4 bleeding from primary tumor site after 2nd administration and therefore was excluded. For safety reasons, 6 more pts. were enrolled - without further DLT. On dose level 2 (D 40 mg/m2, Ox 70 mg/m2, Cape 800 mg/m2), diarrhea and mucositis grade 3 occurred as DLT in 2/2 patients. Level 1 was determined as MTD and 5 more pts were included to a total of 12 with toxicity displayed at the table. Out of 10 pts with measurable disease, 3 had a PR, 4 more had disease stabilization. Median PFS of all pts (5 censored) is 3.9+ (1–9.3+) mos. whereas median OS is not yet reached. Conclusion: TEX can safely be administered without higher graded toxicity in pts with GC. Preliminary efficacy results indicate promising activity that merits further testing in a phase II trial. [Table: see text]

[Table: see text]

Overexpression of bcl-2 in T cells affects insulitis in the nonobese diabetic mouse

The nonobese diabetic (NOD) mouse is a useful model for human autoimmune diabetes. The gene for the anti-apoptotic protein Bcl-2 has previously been suggested as a probable susceptibility candidate for the NOD mouse disease. In this study, we investigated how overexpression of Bcl-2 in lymphocytes might affect insulitis in NOD mice. A bcl-2 transgene expressed constitutively under the SV40-promoter and the 5'Igh enhancer, Emu, was bred onto NOD background. Two bcl-2 transgenic NOD strains were produced and analysed, one with overexpression of Bcl-2 on only B cells and the other with overexpression of Bcl-2 on both B and T cells. Subsequent to verification of expression pattern and functionality of the transgene, insulitis intensity was investigated in different backcross generations of the two transgenic strains. Overexpression of Bcl-2 on both B and T cells leads to a statistically significant protection of the mice from insulitis compared with normal littermates. Overexpression of Bcl-2 on only B cells, on the other hand, does not have any statistically significant effect on insulitis. Possible mechanisms for the effect of Bcl-2 on insulitis in NOD mice are discussed.

[The TRALI syndrome--a life-threatening transfusion reaction]

Transfusion related acute lung injury (TRALI) is a serious complication of blood transfusion, characterized by non-cardiogenic lung oedema. We describe a case of TRALI due to granulocyte-specific antibodies. The 58-year-old patient received 2 units of fresh frozen plasma following colon surgery and within 30 min the patient developed an acute respiratory distress syndrome. Granulocyte-specific antibodies were found in one of the transfused plasma of a female blood donor who most likely became immunized against granulocyte alloantigens during her three pregnancies.

Limits of peritoneal cytokine measurements during abdominal lavage treatment for intraabdominal sepsis

BACKGROUND

Monitoring of peritoneal cytokine concentrations of tumor necrosis factor (TNF)-alpha was recommended for early detection of severe postoperative complications. In the present study the clinical application of cytokine monitoring was examined in the treatment course of severe peritonitis.

METHODS

Nineteen patients with secondary peritonitis were followed up during 75 abdominal lavages. Serum and peritoneal interleukin (IL)-6, IL-8, and IL-10 and TNF-alpha were measured before the surgical intervention, after 1 hour, 3 hours, 6 hours, and 24 hours. Additionally, cardiorespiratory parameters, osmolarity, C-reactive protein, and total leucocyte count were recorded.

RESULTS

Serum and peritoneal cytokine concentrations did not correlate to each other as well as to the observed cardiorespiratory parameters. Peritoneal cytokine concentrations were 10- to 1000-fold higher to serum concentrations and showed an intermittent wash out. There were no differences in determined cytokine concentrations between survivors and nonsurvivors.

CONCLUSIONS

Once elevated, peritoneal cytokine measurements offer no new diagnostic or prognostic tool in abdominal lavage peritonitis treatment.

E expression is needed on both bone marrow derived cells and thymic epithelium to increase IL-4 production and achieve protection in NOD bone marrow chimeras

The NOD mouse is an animal model for insulin-dependent diabetes with many similarities to the human disease. NOD mice which are transgenic for the Ea gene, allowing expression of the E molecule, are protected from diabetes and rarely develop insulitis. We have constructed bone marrow chimeras between transgenic and non-transgenic NOD mice to study the correlation of E expression on bone marrow derived cells and thymic epithelium vs the production of IL-4 and IFN-gamma. We show that NOD-E-->NOD-E and NOD-E-->NOD chimeras have elevated levels of IL-4 compared to NOD-->NOD and NOD-->NOD-E chimeras in the thymus. However, in the periphery the protected NOD-E-->NOD-E show much higher IL-4 levels than any of the other chimeras. This drop in peripheral IL-4 production seen in NOD-E-->NOD, NOD-->NOD-E and NOD-->NOD chimeras correlates with the increased insulitis seen in these mice compared to NOD-E-->NOD-E. In contrast, there were no differences in IFN-gamma production between the chimeras. We suggest that the precommitted, regulatory T cells, selected in an E-expressing thymic environment, need continuous interaction with E-expressing primary antigen presenting cells in the periphery for optimal IL-4 production. Decrease in IL-4 production correlates with increased insulitis.

Minute defects in the expression of MHC E molecules lead to impaired protection from autoimmunity in NOD mice

The E complex of the major histocompatibility complex (MHC) can prevent the spontaneous development of diabetes in nonobese diabetic (NOD) mice transgenic for the Ea gene. None of three promoter-mutated Ea constructs with Ea expression directed to different subsets of immunocompetent cells exerts full protection in NOD mice. The promoter-mutated constructs are all capable of mediating intrathymic elimination of I-E-restricted T cells. Thus, thymic negative selection is not responsible for the protective effect but a more complex effect is likely. Here we show that combinations of two or three different mutated Ea constructs do not protect against intra-islet insulitis either. We also show that spleen cells from protected animals are sufficient to protect NOD mice in adoptive transfer experiments. The only detectable expression defects in splenic cells or cells influencing the repertoire of splenic cells are in the B-cell compartment. Furthermore, in three construct combinations, the differences to wild-type expression are extremely small. Thus, we conclude that even minute disturbances of the E expression pattern might reduce the protection of NOD mice from insulitis.

Gene conversion of major histocompatibility complex genes is associated with CpG-rich regions

We examined 32 DNA sequences of mouse and human major histocompatibility complex (MHC) genes believed to have been subjected to gene conversion events. All regions of the mouse H2 genes as well as the human HLA genes which have been implied to be involved in gene conversion events had elevated levels of CpG dinucleotides, whereas the rest of the genes showed extensive CpG suppression. Mouse MHC genes which have been suspected but not directly implied to be involved in gene conversion events also showed elevated levels of CpG dinucleotides. Moreover, both mouse and human MHC genes which have never been suspected of undergoing gene conversion had low levels of CpG throughout the genes. These results indicate that high CpG levels are correlated with gene conversion rather than with polymorphism, as non-polymorphic genes that have been implicated as gene conversion donors also have elevated levels of CpG dimers in the involved regions, whereas polymorphic genes which have never been considered to undergo gene conversion events have a low level of CpG dinucleotides. We also studied the methylation pattern of CpG dimers in the Abk gene by restriction enzyme digestion of mouse testis DNA followed by Southern blot and hybridization to an Abk-specific probe. The examined CpG dimers in prepubescent mice, where the latest germline stages are spermatogonia, leptene, or pachytene, are respectively non-methylated. Accordingly, the CpG dimers appear to be non-methylated in germline DNA from the testis of prepubescent mice, where gene conversions have been reported to occur.

Gene conversion can create new MHC alleles

It is possible to measure gene conversion of MHC genes with the help of a semi-nested PCR assay. Several considerations are of utmost importance when such an assay is set up. Using this assay, we have found that gene conversion occurs in MHC class II genes in mouse sperm, but not in somatic cells tested. Although this gene conversion occurs in germline cells, it is already completed in spermatogonia, and consequently is mitotic event unlinked to meiosis. The frequency of gene conversion events in MHC class II genes varies strongly from one allele to another, with the highest detected frequencies as high as 1/40,000 for an individual heterozygous for both donor and acceptor sequences. Deletions or insertions in one gene relative to the other seem to lower the efficiency of gene conversion considerably. Stretches within MHC genes amenable to gene conversion are located in CpG clusters, whereas MHC genes not involved in gene conversion have background CpG levels. DNA damage, either chemical or radiation induced, increases the frequency of gene conversion of MHC class II genes in cultured cells of the fibroblastoid lineage. The effect of chemical DNA damage seems roughly dose dependent, whereas irradiation has a maximal effect at low doses.

DNA damage caused by etoposide and gamma-irradiation induces gene conversion of the MHC in a mouse non-germline testis cell line

We have explored the effects of gamma-irradiation and etoposide on the gene conversion frequency between the endogenous major histocompatibility complex class II genes Abk and Ebd in a mouse testis cell line of non-germline origin with a polymerase chain reaction assay. Both gamma-rays and etoposide were shown to increase the gene conversion frequency with up to 15-fold compared to untreated cells. Etoposide, which is an agent that stabilise a cleavable complex between DNA and DNA topoisomerase II, shows an increased induction of gene conversion events with increased dose of etoposide. Cells treated with gamma-rays, which induce strand breaks, had an increased gene conversion frequency when they were subjected to low doses of irradiation, but increasing doses of irradiation did not lead to an increase of gene conversion events, which might reflect differences in the repair process depending on the extent and nature of the DNA damage. These results where DNA damage was shown to be able to induce gene conversion of endogenous genes in mouse testis cells suggests that the DNA repair system could be involved in the molecular genetic mechanism that results in gene conversion in higher eukaryotes like mammals.

Differential MHC expression requirements for positive selection of separate TCR Vb families

Positive selection has been proposed to be involved in protection from diabetes. We examined positive selection by fluorescence-activated cell sorter analyses in thymocytes of protected and susceptible E-transgenic and non-transgenic NOD mice. Three Vb families showed positive selection in E-transgenic mice. Vb6(+)CD4(+) and Vb10(+)CD4(+) thymocytes were found at higher frequencies in both protected NOD-Ea and susceptible NOD-DY mice. The increased frequencies of Vb13(+)CD8(+) thymocytes were found in protected NOD-Ea mice only, and not in susceptible NOD-DY transgenic mice. These three Vb families were further examined in bone-marrow chimeras between NOD-Ea and non-transgenic NOD mice, where we could examine the contribution of E-expressing bone-marrow-derived cells in positive selection. We find that NOD-Ea-->NOD-Ea chimeras have an increased positive selection of Vb13(+)CD8(+) cells and that positive selection is more efficient when both thymic epithelium and bone-marrow-derived cells express the E molecule. This was also seen for Vb6(+)CD4(+) cells. However, for Vb6, bone-marrow-derived cells alone were also capable of positive selection. Positive selection of Vb10(+)CD4(+) cells was restricted to E-expressing thymic epithelium only. For Vb13(+)CD8(+ )cells, we found that positive selection is most efficient with E-expression on both thymic epithelium and bone-marrow-derived cells, although positive selection also occurs with E-positive epithelium only. For Vb6(+) CD4(+) cells, the dominating selecting cells are bone-marrow-derived cells, and Vb10(+)CD4(+ )cells seem to be selected exclusively by the thymic epithelium. Thus, the conditions for positive selection seem to vary considerably between different Vb families.

Disease-protected major histocompatibility complex Ea-transgenic non-obese diabetic (NOD) mice show interleukin-4 production not seen in susceptible Ea-transgenic and non-transgenic NOD mice

The non-obese diabetic (NOD) mouse is an animal model for insulin-dependent diabetes that has many similarities to the human disease. NOD mice transgenic for the Ea gene, allowing expression of the E molecule, are protected from diabetes and rarely develop insulitis. An Ea transgene mutated in the promoter region, (DeltaY) lacks E expression on most B cells, thymic medullary epithelium and primary antigen-presenting cells, and confers no protection whatsoever. We have used these transgenic NOD mice, together with non-transgenic NOD mice, to study the correlation of E expression and production of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma). We show that protected E-transgenic NOD mice have elevated levels of IL-4 compared with non-transgenic mice, both in the thymus and in the periphery. However, susceptible DeltaY-transgenic mice have elevated thymic IL-4 levels, but express almost as little IL-4 as non-transgenic NOD mice in the periphery. This drop in peripheral IL-4 production seen in DeltaY-transgenic mice thus correlates with the decreased E expression in the periphery of DeltaY-transgenic NOD mice. In contrast, there were no differences in IFN-gamma production between the three NOD lines. We suggest that Ea-transgenic NOD mice have E-selected regulatory T cells producing IL-4, which are subsequently activated by E-expressing primary antigen-presenting cells in the periphery. This activation would then be instrumental for the E-mediated protection from disease in NOD mice. Such a process would explain the total absence of protection in DeltaY-transgenic NOD mice, despite their widespread E expression.

Intrachromosomal gene conversion frequency in the H2 differs between haplotypes

We examined two intrachromosomal gene conversion events with a polymerase chain reaction assay at the DNA level between the two major histocompatibility complex class II genes Eb and Ab in mice sperm before selection has occurred. The frequency of the intrachromosomal gene conversion event between Ebd and Abd was found to be at least one order of magnitude higher than between Ebk and Abk in the same mice. Parental imprinting of the genes appears not to have an effect on gene conversion, as both (dxk)F1 and (kxd)F1 mice have indistinguishable frequencies in both haplotypes. The number of DNA copies of the donor and acceptor genes present in the cell at the time of mutation does not seem to influence the frequency of the intrachromosomal gene conversion in the k haplotype, whereas the frequency in the d haplotype is increased when double the number of donor and acceptor genes is present. The DNA fragment transferred between Ebd and Abd is invariably short, and need not comprise more than six nucleotides. The fragment transferred within the k haplotype varies in length, and can attain at least 100 nucleotides. The difference between the haplotypes both in length and frequency might be attributed to a six-nucleotide deletion in the Abk gene, which might make base-pairing between the genes less efficient and less precise.

Timing and effects of template number for gene conversion of major histocompatibility complex genes in the mouse

Pachytene spermatocytes and haploid spermatocytes from adult mice, as well as testis cells from prepubescent mice were analysed for the presence of gene conversion products resulting from the transfer between the MHC class II genes Ebd and Abk in a PCR assay. Gene conversion products were detected in testis cells as early as in 8 days old mice, where the only existing spermatogenic cells are spermatogonia. The frequency of gene conversion products remains the same as the cells reach meiosis in 18 days old mice or in pachytene cells, and is unchanged after meiosis is completed in haploid spermatocytes, thus indicating that gene conversion is largely completed already in the mitotically dividing spermatogonia. We have furthermore analysed the frequency of gene conversion between the Eb and Ab loci within the same MHC haplotype, the k haplotype. The frequency of such events is the same in animals with one and two copies of the same haplotype, and consequently seems to be independent of template number.

Gene conversion of major histocompatibility complex genes in the mouse spermatogenesis is a premeiotic event

The molecular genetic mechanism of gene conversion in higher eukaryotes remains unknown. We find it of considerable interest to determine when during spermatogenesis gene conversion occurs. We have therefore purified pachytene spermatocytes and haploid spermatocytes from adult mice and analyzed these fractions for the presence of gene conversion products resulting from the transfer between the major histocompatibility complex class II genes Ebd and Abk in a polymerase chain reaction assay. We have further isolated spermatogenic cells from prepubescent mice and analyzed them for the presence of the same gene conversion products. We can detect gene conversion products in testis cells as early as in 8-d-old mice where the only existing spermatogenic cells are spermatogonia. The frequency of gene conversion products remains the same as the cells reach meiosis in 18-d-old mice, and is unchanged after meiosis is completed in haploid spermatocytes. Gene conversion of this specific fragment therefore appears to be a premeiotic event and, consequently, relies on genetic mechanisms other than normal meiotic recombination.

T cells are unresponsive to transgenic MHC class II molecules expressed on pancreatic beta cells

It has been proposed that the autoimmune attack on the pancreatic beta cells leading to insulin-dependent diabetes mellitus can be caused by the expression of MHC class II molecules on the beta cells. Transgenic mice expressing normal levels of allogeneic MHC class II Ak on the beta-cell surface (IP-Ak) do not develop either insulitis or diabetes, yet these mice are not tolerant to Ak when expressed on normal antigen-presenting cells. The authors have stimulated T cells from IP-Ak mice in vitro with Ak-expressing beta cells. Mice were also primed in vivo in order to facilitate the antiallogeneic response. The authors found that neither IP-Ak positive nor IP-Ak negative mice were able to respond to Ak-expressing beta cells, and that in vivo priming does not overcome this inability. They suggest that beta cells do not act as antigen-presenting cells, probably due to inability of delivering costimulatory signals. This strengthens the notion that MHC class II expression per se is not sufficient to induce an autoimmune attack on the beta cells.

Alleviation of insulitis in NOD mice is associated with expression of transgenic MHC E molecules on primary antigen-presenting cells

Major histocompatibility complex (MHC) class II genes are important in the pathogenesis of insulin-dependent diabetes mellitus (IDDM) both in the mouse and in man. The non-obese diabetic (NOD) mouse, which is a good model for human IDDM, has a particular MHC class II with an A complex consisting of A alpha d and the unique A beta g7 chain, as well as an absent E molecule due to a deletion in the Ea promoter region. Transgenic insertion of a functional Ea gene protects against insulitis and diabetes, but when the transgene expression is restricted to certain compartments of the immune system by deleting parts of the promoter region, the protection against insulitis is disrupted. We have analysed three promoter-mutated lines where one lacks expression on B cells and has a reduced expression on approximately 1/3 of the dendritic cells and macrophages (Sma), one lacks thymic cortical expression and has a slightly reduced B-cell expression (delta X), and one lacks expression in the thymic medulla, on macrophages, dendritic cells and about half of the B cells (delta Y). None of these lines is protected against insulitis, but Sma and delta X display a reduced intensity of insulitis, with an average of 10-15% of the islets infiltrated in each mouse, while delta Y resembles non-transgenic mice with 30-35% infiltrated islets. Bone-marrow chimeras between Sma and delta Y mice demonstrate that peripheral cells of Sma origin reduce insulitis significantly when developed in the delta Y host, while insulitis is enhanced when delta Y bone marrow is given to Sma mice. This shows that E expression on the primary antigen-presenting macrophages and dendritic cells is of crucial importance to the alleviation of insulitis.

Monokine-producing cells predominate in the recruitment phase of NOD insulitis while cells producing Th1-type cytokines characterize the effector phase

Cells infiltrating the Langerhans' islets of prediabetic NOD females were isolated from 6 weeks to 6 months of age. These cells were assayed at a single-cell level for production of eight different cytokines by intracellular immunofluorescent staining. Quiescent in vivo preactivated cells were detected by in vitro stimulation with PMA and ionomycin for 4 h. The cell recruitment phase, between 6 and 12 weeks of age, is predominated by production of the monokines IL-1alpha, IL-6, and TNF After stimulation IFN-gamma and occasional IL-10 and GM-CSF producing cells could also be observed. This cytokine pattern occurs simultaneously with increasing insulitis, and we suggest that these cytokines are important in attracting inflammatory cells to the islets and maintaining the inflammatory state. A high frequency of endocrine cells producing IL-6 during this period may denote a stress response caused by initial beta-cell destruction due to cytokines released by the inflammatory cells. During the effector phase, between 4 and 6 months, there is a characteristic Th1 cytokine profile with lymphocytes producing IL-2, IFN-gamma and TNF, supposedly TNF-beta. No IL-4 production could be detected and IL-10 was very rarely found, indicating the absence of a Th2 response. Our findings show that the effector phase in NOD insulitis is a Th1 rather than a Th2-mediated event. We also demonstrate that cytokines that may cause initial tissue destruction are produced during the recruitment of inflammatory cells.

Demonstration of a TH1 cytokine profile in the late phase of NOD insulitis

Cells infiltrating the Langerhans' islets of prediabetic NOD females were isolated from 6 weeks to 6 months of age. These cells were assayed at a single-cell level for production of eight different cytokines by intracellular immunofluorescent staining. By in vitro stimulation with PMA and ionomycin for 4 hours the method is enhanced also to detect in vivo preactivated cells. During the early phase of insulitis from 6 to 12 weeks of age, mainly the monokines IL-1 alpha, IL-6, and TNF were detected. After stimulation, also IFN-gamma and low numbers of IL-10 and GM-CSF producing cells could be observed, but no IL-2 or IL-4 was seen. This cytokine pattern correlates with an increasing insulitis, and we suggest that these cytokines are important in attracting inflammatory cells to the islets, and may cause initial beta-cell destruction. During a later phase, between 4 and 6 months, there is a characteristic TH1 cytokine profile with production of IL-2 and IFN-gamma occurring after stimulation, as well as lymphocytes producing TNF, supposedly TNF-beta. During this period IL-10 was very rarely observed, and no IL-4 production could be found throughout the study. This indicates the absence of a TH2 cytokine profile in this lesion. In addition IL-6 production occurs in high frequencies at all ages, also in endocrine islet cells. We interpret this as a stress response caused by the inflammatory lesion. Our findings show that the effector phase in NOD insulitis is TH1 rather than TH2 mediated. We also demonstrate that cytokines, that may cause initial tissue destruction, are produced during the recruitment of inflammatory cells.

No evidence for TCR V beta repertoire changes influencing disease protection in E-transgenic NOD mice

In order to study whether positive selection of T cells plays any role in the MHC-dependent protection from diabetes in the non-obese-diabetic (NOD) mouse, the T cell V beta repertoire has been studied in NOD mice and in NOD mice either transgenic for the wildtype MHC class II E alpha gene, or for delta Y, a promotor-mutagenized E alpha gene with a restricted tissue expression. The E alpha transgenic line is protected from both insulitis and diabetes. The delta Y transgenic line is neither protected from insulitis nor from diabetes, although it can perform both positive and negative E-mediated selection in the thymus. The V beta repertoire was studied in the pancreatic lymph nodes as these drain the area which is the target for the autoimmune attack. We see no evidence for E alpha TCR V beta repertoire differing from both nontransgenic NOD mice and delta Y mice despite its striking difference in susceptibility to autoimmunity. We conclude that none of the differences in the TCR V beta repertoire of E alpha-transgenic NOD mice hitherto observed are likely to explain the protective effect of E molecule expression in NOD mice.

A determination of the frequency of gene conversion in unmanipulated mouse sperm

Gene conversion, sometimes also called micro gene conversion or gene conversion-like events, has been proposed to act on a number of genes in higher eukaryotes, such as gamma-globin, beta-tubulin, major urinary protein, and amyloid A genes. In the immune system, immunoglobulin genes and major histocompatibility complex class I and class II genes have been implicated. The notion that integral segments of DNA have been transferred from one gene to another in these cases has, however, met considerable resistance. We have devised a PCR assay detecting only the molecule that results if the E beta d-derived fragment analogous to that introduced in the bm12 mutation is transferred to the A beta k gene. We have proceeded to analyze sperm from the F1 cross C3H/HeJ (haplotype k) x BALB/c (haplotype d). In our assay, we find that the frequency for conversion of this particular DNA segment is 2 x 10(-6). This frequency is relevant only in the germ line; when liver cells were tested as an example of somatic cells, no events were observed, implying a frequency of < 2 x 10(-8) in liver. Fragments > 100 bp seem to be possible to transfer in this conversion.

Enzyme-catalysed enantioselective hydrolysis of racemic naproxen nitrile

The bacterial strain Rhodococcus butanica (ATCC 21197), which exhibits nitrilase and nitrile hydratase/amidase activities, catalyses the enantioselective hydrolysis of racemic naproxen nitrile (R/S)-1 to furnish a moderate enantiomeric excess of (S)-naproxen (S)-3. Racemic naproxen amide (R/S)-2 is not a good substrate for this strain. Resting cells of the newly selected bacterial strain Rhodococcus sp. C3II catalyse the enantioselective hydrolyses of racemic naproxen nitrile (R/S)-1 and naproxen amide (R/S)-2 as well, to give (S)-3 in excellent optical (99% e.e.) and good chemical yields in aqueous medium and in the biphasic system of phosphate buffer/hexane.

Enantioselective hydrolysis of racemic naproxen nitrile and naproxen amide to S-naproxen by new bacterial isolates

Bacteria were enriched from soil samples with succinate as a carbon source and racemic naproxen nitrile [2-(6-methoxy-2-naphthyl)propionitrile] as sole source of nitrogen. Since naproxen nitrile was only poorly soluble in water media amended with different water-immiscible organic phases were used for the enrichments. With pristane (2,6,10,14-tetramethylpentadecane) as the organic phase two bacterial strains were isolated (strain C3II and strain MP50) which were identified as rhodococci. Cells of both strains converted naproxen nitrile via naproxen amide to naproxen. From racemic naproxen nitrile Rhodococcus sp. C3II formed S-naproxen amide and subsequently S-naproxen. Racemic naproxen amide was hydrolysed to S-naproxen. Rhodococcus sp. MP50 converted racemic naproxen nitrile predominantly to R-naproxen amide and racemic naproxen amide to S-naproxen. With both strains racemic naproxen amide was converted to S-naproxen with an enantiomeric excess > 99% at a conversion rate up to 80% of the theoretical value. In strain C3II the enzymes which hydrolysed naproxen nitrile and naproxen amide were present only at a low constitutive level. In contrast, in Rhodococcus sp. MP50 these activities were induced when grown in the presence of various nitriles.