Immune response of heterologous versus homologous prime-boost regimens with adenoviral vectored and mRNA COVID-19 vaccines in immunocompromised patients

Due to rare but major adverse reactions to the AstraZeneca adenoviral ChAdOx1-S-nCoV-19 vaccine (ChAd), German health authorities recommended adults under 60 who received one dose of ChAd, to receive a second dose of the BioNTech mRNA BNT162b2 vaccine (BNT) as a booster. Studies in the general population suggest an enhanced efficacy of the heterologous (ChAd-BNT) compared to the homologous (BNT-BNT) vaccination regimen. However, an analysis of the efficacy in patient populations with a high risk of severe COVID-19 due to acquired immunodeficiency is still missing. We therefore compared both vaccination regimens in healthy controls, patients with gynecological tumors after chemotherapy, patients on dialysis and patients with rheumatic diseases concerning the humoral and cellular immune response. The humoral and cellular immune response differed substantially in healthy controls compared to patients with acquired immunodeficiency. Overall, the most significant differences between the two immunization regimens were found in neutralizing antibodies. These were always higher after a heterologous immunization. Healthy controls responded well to both vaccination regimens. However, the formation of neutralizing antibodies was more pronounced after a heterologous immunization. Dialysis patients, on the other hand, only developed an adequate humoral and particularly cellular immune response after a heterologous immunization. Tumor and rheumatic patients also - to a weaker extent compared to dialysis patients - benefited from a heterologous immunization. In conclusion, the heterologous COVID-19 vaccination regimens (ChAd-BNT) seem to have an advantage over the homologous vaccination regimens, especially in immunocompromised patients such as patients with end-stage kidney disease treated with hemodialysis.

Impact of hypertension on long-term humoral and cellular response to SARS-CoV-2 infection

It was shown that hypertension delays SARS CoV-2 viral clearance and exacerbates airway hyperinflammation in the respiratory tract. However, it is unknown whether hypertension determines the long-term cellular and humoral response to SARS Cov2. Health care workers (HCWs) after an outbreak of SARS Cov-2 infections were analyzed. Infected HCWs were not vaccinated before blood collection. 5-14 months (median 7 months) after detection of SARS CoV-2 infection, blood was taken to analyze humoral response (S1 IgG and SARS CoV-2 neutralizing antibodies) and cellular (T cell responses to SARS-CoV-2 with Lymphocyte Transformation Test). To identify clinical factors that determine the immune response, a multivariate regression analysis was done considering age, BMI, sex, diabetes, hypertension, smoking, COPD, asthma and time between PCR positivity and blood collection as confounding factors. Infected hypertensive HCWs more often needed to be hospitalized than non-hypertensive HCWs, but were less likely to develop anosmia and myalgia. The long-term humoral and cellular immune response was significantly strengthened in hypertensive versus normotensive infected HCWs. Multivariate regression analysis revealed that hypertension was independently associated with the humoral response to SARS CoV-2 infection. Multivariate regression analysis using same confounding factors for the humoral response showed a clear trend for an association with the cellular response to SARS CoV-2 infection as well. In conclusion, SARS CoV-2 infection strengthened immune response to SARS CoV-2 infection in hypertensive HCWs independent of other risk factors.

T-cell proliferation assay for the detection of SARS-CoV-2-specific T-cells

Both infection with and vaccination against SARS-CoV-2 trigger a complex B-cell and T-cell response. Methods for the analysis of the B-cell response are now well established. However, reliable methods for measuring the T-cell response are less well established and their usefulness in clinical settings still needs to be proven. Here, we have developed and validated a T-cell proliferation assay based on 3H thymidine incorporation. The assay is using SARS-CoV-2 derived peptide pools that cover the spike (S), the nucleocapsid (N) and the membrane (M) protein for stimulation. We have compared this novel SARS-CoV-2 lymphocyte transformation test (SARS-CoV-2 LTT) to an established ELISA assay detecting Immunoglobulin G (IgG) antibodies to the S1 subunit of the SARS-CoV-2 spike protein. The study was carried out using blood samples from both vaccinated and infected health care workers as well as from a non-infected control group. Our novel SARS-CoV-2 LTT shows excellent discrimination of infected and/or vaccinated individuals versus unexposed controls, with the ROC analysis showing an area under the curve (AUC) of > 0.95. No false positives were recorded as all unexposed controls had a negative LTT result. When using peptide pools not only representing the S protein (found in all currently approved vaccines) but also the N and M proteins (not contained in the vast majority of vaccines), the novel SARS-CoV-2 LTT can also discriminate T-cell responses resulting from vaccination against those induced by infection.

[Improve your skills!: evaluation of a 2.5-day basic course in vascular surgery for surgical trainees]

BACKGROUND

The traditional surgical training in the operating room (OR) is often complemented by participation in workshops and on simulators. The foundation Vascular International offers basic courses for vascular surgery techniques with training on pulsatile circulation, lifelike anatomical models. The aim of this study was to assess the efficacy of a 2.5-day intensive course on basic skills in vascular surgery.

MATERIAL AND METHODS

A total of 24 participants (67% male with an average age of 35 years) performed a vein patch-plasty before and after the basic vascular surgery instruction course. Endpoints of the study were the time needed for suturing and the technical quality, which were evaluated by two course trainers on a scale of 0-10. Furthermore, the participants were asked to evaluate their own technical competence. The statistical analysis was carried out using MS Excel (t-test and analysis of correlation).

RESULTS

A significantly shortened time for the suturing (19.5 min versus 14.1 min, p < 0.001) and improved quality of the vein patch were found after the workshop (p < 0.05) with a high correlation between the two observers (r = 0.885). The participants also evaluated their own surgical competence better at the end of the training but there was no correlation between the self-assessment and the quality of the patch (r = 0.146 before and r = 0.109 after the workshop).

CONCLUSIONS

A significant improvement in the time needed for suturing and the quality of the vein patch-plasty was shown in this study. Further studies are necessary to demonstrate the long-term success and possible shortening of the learning curve in hospitals with professional training. With regard to the current curriculum of surgical trainees in Germany basic vascular surgery courses should be considered as a potential valuable part of the surgical common trunk.

Small molecule GSK-3 inhibitors increase neurogenesis of human neural progenitor cells

Human neural progenitor cells provide a source for cell replacement therapy to treat neurodegenerative diseases. Therefore, there is great interest in mechanisms and tools to direct the fate of multipotent progenitor cells during their differentiation to increase the yield of a desired cell type. We tested small molecule inhibitors of glycogen synthase kinase-3 (GSK-3) for their functionality and their influence on neurogenesis using the human neural progenitor cell line ReNcell VM. Here we report the enhancement of neurogenesis of human neural progenitor cells by treatment with GSK-3 inhibitors. We tested different small molecule inhibitors of GSK-3 i.e. LiCl, sodium-valproate, kenpaullone, indirubin-3-monoxime and SB-216763 for their ability to inhibit GSK-3 in human neural progenitor cells. The highest in situ GSK-3 inhibitory effect of the drugs was found for kenpaullone and SB-216763. Accordingly, kenpaullone and SB-216763 were the only drugs tested in this study to stimulate the Wnt/β-catenin pathway that is antagonized by GSK-3. Analysis of human neural progenitor differentiation revealed an augmentation of neurogenesis by SB-216763 and kenpaullone, without changing cell cycle exit or cell survival. Small molecule inhibitors of GSK-3 enhance neurogenesis of human neural progenitor cells and may be used to direct the differentiation of neural stem and progenitor cells in therapeutic applications.

Local versus global interactions in nonequilibrium transitions: A model of social dynamics

A nonequilibrium system of locally interacting elements in a lattice with an absorbing order-disorder phase transition is studied under the effect of additional interacting fields. These fields are shown to produce interesting effects in the collective behavior of this system. Both for autonomous and external fields, disorder grows in the system when the probability of the elements to interact with the field is increased. There exists a threshold value of this probability beyond which the system is always disordered. The domain of parameters of the ordered regime is larger for nonuniform local fields than for spatially uniform fields. However, the zero field limit is discontinous. In the limit of vanishingly small probability of interaction with the field, autonomous or external fields are able to order a system that would fall in a disordered phase under local interactions of the elements alone. We consider different types of fields which are interpreted as forms of mass media acting on a social system in the context of Axelrod's model for cultural dissemination.

[Early transfer from intensive care does not influence clinical results of carotid endarterectomy]

The purpose of this prospective observational study was to examine the necessity of intensive care after carotid endarterectomy (CEA). In consideration of the neurological stage and comorbidities, morbidity and mortality after early transfer from the intensive care unit (ICU) were examined. The CEA patients were assigned preoperatively to short or long monitoring. Those with symptomatic stenosis ranking > or =2 (stroke within 6 weeks before surgery) and ischemic areas in cCT were observed overnight (long) in the ICU. Within 5.5 months, 100 consecutive patients had received 107 CEAs. Preoperatively, seven of these (6.54%) were assigned to ICU overnight monitoring. 14 patients (13%) needed postoperative over night ICU. We observed no perioperative stroke or mortality in the 107 consecutive CEAs. We could not detect any risk factor in preoperatively determining the length of postoperative ICU monitoring. This prospective, single center study showed that, after CEA, it is safe to monitor patients for only a short period (4-8 h) in the ICU. Morbidity and mortality after early transfer to the regular ward did not increase.

XX male: a rare cause of short stature, infertility, gynaecomastia and carcinoma of the breast

We present a case of an XX male with carcinoma of the breast and primary infertility. He was admitted to hospital with recurrent chest pains, but a history of surgery for breast carcinoma, gynaecomastia and the finding of bilaterally atrophied testes, coupled with the fact that he had never fathered children, necessitated further investigations. Chromosomal analysis showed a 46, XX male genotype with a normal X chromosome and an abnormal X chromosome formed by translocation between the short arm of one X chromosome and the Y chromosome. By using fluorescence in situ hybridisation, the patient proved to be SRY positive, the sex-determining region of the Y chromosome. In this rare genetic abnormality, males retain normal phenotype but they are generally of short stature, have gynaecomastia, and may have genital anomalies. They are infertile and at increased risk of developing carcinoma of the breast. This seems to be the first documented case of carcinoma of the breast in an SRY positive XX male. This particular case illustrates the need for all cases of male breast cancer to undergo full endocrinological assessment, especially in the presence of genital anomaly or infertility.

Improvement of carotid blood flow after carotid endarterectomy--evaluation using intraoperative ultrasound flow measurement

OBJECTIVES

to examine the relationship between the degree of extracranial internal carotid artery (ICA) stenosis and changes in the ipsilateral ICA blood flow after carotid endarterectomy (CEA).

MATERIALS AND METHODS

in a prospective study we studied 51 patients with unilateral 60-99% ICA stenosis (median degree 84%, asymptomatic stenosis n = 13, symptomatic stenosis n = 38). The degree of ICA diameter stenosis was determined by ex-vivo plastination of the surgically removed atherosclerotic specimen and video-assessed planimetry. Intraoperative transit time ultrasound flow measurements of the carotid arteries were performed before and after CEA. Blood flow changes were assessed by mathematical approximations. Statistics were done by use of the Wilcoxon signed Rank test.

RESULTS

common carotid artery (CCA) and ICA median blood flow increased after CEA from 370 and 130 ml/min to 450 and 282 ml/min, respectively (p <.001). The relative increase of ICA blood flow was 5% and 18% for 60-69% and 70-79% ICA stenosis (n.s.) but 70% and 247% for 80-89% and 90-99% stenosis (p <.001 each). Mathematical evaluation (fourth-polynomal function) determined a significant increase of carotid blood flow after CEA in ICA stenosis of > or =82.3%.

CONCLUSIONS

in the absence of severe contralateral ICA occlusive disease a significant increase of ipsilateral ICA blood flow by CEA can be expected in patients with an ICA stenosis of > or =82.3% (linear degree of stenosis, ECST criteria).

The Carotid Surgery for Ischemic Stroke trial: a prospective observational study on carotid endarterectomy in the early period after ischemic stroke

OBJECTIVE

The purpose of this study was to examine the safety of carotid endarterectomy (CEA) within 6 weeks after a nondisabling carotid-related ischemic stroke. Endpoints were the perioperative stroke or mortality rate and the incidence rate of cerebral bleedings.

METHODS

This prospective observational multicenter trial was performed in community and university centers. One hundred sixty-four hospitalized patients with nondisabling carotid-related ischemic stroke were included. The patients were identified clinically with the modified Rankin scale (initial neurologic deficit grade >/= 2, n = 160). Four patients with evidence of ischemic territorial infarction on cerebral computed tomographic (CT) scan but no persisting functional deficit were also included. CEA was performed within 6 weeks after stroke. Neurologic examinations were performed initially, before surgery, 3 days after surgery, and 6 weeks after CEA. Worsening of more than 1 grade on the Rankin scale was considered as a new stroke or stroke extension. Unenhanced CT scans of the brain were performed before and after surgery. CT scans were evaluated blind to clinical patient data. Statistical analysis included univariate and multivariate analysis.

RESULTS

The combined stroke or mortality rate within 30 days after CEA was 6.7%. Ten patients had a new ipsilateral stroke or stroke extension, and one patient died after surgery of a myocardial infarction. One patient (0.6%) had parenchymatous cerebral bleeding, and in 10 patients, hemorrhagic transformation within the preexisting ischemic infarction was detected but no infarct extension was observed. In the multivariate analysis, American Society of Anesthesiology (ASA) grades III and IV and decreasing age were significant predictors for an increased perioperative risk. Patients with a higher risk profile (ASA classification grades III and IV) had a high perioperative risk when CEA was performed within the first 3 weeks (14.6% versus 4.8% beyond 3 weeks). Patients without severe concomitant diseases (ASA grades I/II) had a low perioperative risk of 3.4% if CEA was performed within the first 3 weeks.

CONCLUSION

Early CEA within 6 weeks after a carotid-related ischemic stroke can be performed with a perioperative stroke or mortality rate comparable with the results reported in the European Carotid Surgery Trial and the North American Symptomatic Carotid Endarterectomy Trial. The risk of parenchymatous bleeding is low. ASA grades III and IV and decreasing age were predictive of an increased perioperative risk, especially if CEA was performed within the first 3 weeks. Patients at low risk can undergo operation safely within the first 3 weeks. Individual patient selection in an interdisciplinary approach between neurologists, anesthesiologists, and vascular surgeons remains mandatory in these patients.

Grading of Internal Carotid Artery Stenosis: Validation of Doppler/Duplex Ultrasound Criteria and Angiography Against Endarterectomy Specimen

OBJECTIVES

duplex ultrasound has replaced angiography prior to carotid endarterectomy (CEA) in many institutions. However, the indications for CEA are based on angiographically controlled studies and widely accepted ultrasound criteria do not exist. Consequently, the reliability of Doppler and/or duplex ultrasound to predict a high-grade ICA stenosis has to be proven.

DESIGN

prospective validation study.

MATERIALS

one hundred and fifty carotid bifurcations assessed by ultrasound and selective angiography and 68 acrylat outcasts of carotid specimen after eversion CEA.

METHODS

ICA stenosis was measured angiographically according to the ECST criteria. Combined Doppler acoustic standard criteria (CDASC), peak systolic frequency (PSF), peak systolic velocity (PSV) and end-diastolic velocity (EDV) served as criteria for the ultrasound assessment. These criteria and the results of angiography were compared to the degree of ICA stenosis determined by specimen measurements.

RESULTS

the median degree of ICA stenosis as assessed by angiography (82%, range 56-97%) and CDASC (83%, range 50-99%) corresponded well to the specimen measurements (80%, range 50-95%). The sensitivity of angiography and CDASC to predict a 70-90% ICA stenosis (ECST criteria) compared to the specimen measurements was 88% and 95%, respectively. The positive predictive value (PPV) reached 92% and 96%, respectively. CDASC were equivalent to angiography and were superior to the best single frequency or velocity parameters. If CDASC do not indicate a >/=70% ICA stenosis in spite of a PSV >/=180 cm/s and/or an EDV >/=50 cm/s, angiography may detect patients with a >70% ICA stenosis.

CONCLUSIONS

CDASC are valid in the quantification of high-grade ICA stenosis. They are more reliable than single velocity and/or frequency measurements. However, if velocity criteria and CDASC do not agree, angiography should be performed.

The use of antibiotic-containing bead chains in the treatment of chronic bone infections

The implantation of gentamicin polymethylmethacrylate (PMMA) chains or minichains into infected osteomyelitic cavities is a well-established local antibiotic therapy supplementary to radical debridement. The gentamicin concentrations achieved at the site of infection are far above the MICs for most common pathogens in chronic osteomyelitis. Serum and urine concentrations are low, and nephrotoxic and ototoxic side-effects of this form of gentamicin application are not to be feared. Under local antibiotic therapy with gentamicin PMMA chains, primary wound healing as in aseptic surgery can be expected. Prolonged systemic antibiotic therapy is unnecessary. In a series of 405 cases, a success rate of 90.4% was obtained.

Beyond Hebb: exclusive-OR and biological learning

A learning algorithm for multilayer neural networks based on biologically plausible mechanisms is studied. Motivated by findings in experimental neurobiology, we consider synaptic averaging in the induction of plasticity changes, which happen on a slower time scale than firing dynamics. This mechanism is shown to enable learning of the exclusive-OR (XOR) problem without the aid of error backpropagation, as well as to increase robustness of learning in the presence of noise.

Emergency carotid endarterectomy

OBJECTIVE

Evaluation of the therapeutical efficacy of emergency carotid endarterectomy (CEA) in neurologically unstable patients.

PATIENTS AND METHODS

Three groups of a consecutive series of 71 emergency CEAs performed from 1980 to July 1998 were classified: (1) acute onset of severe stroke (n = 16), (2) progressive stroke/stroke in evolution (n = 34), and (3) crescendo transient ischemic attacks (n = 21). Cerebral coma, cerebral haemorrhage, and major ischemic stroke established in cranial computed tomography scans were contraindications for surgery. The neurological outcome was assessed by the modified Rankin scale. Long-term survival and long-term stroke recurrences were analyzed.

RESULTS

The recovery/minor stroke rates (Rankin 0-3) in acute stroke, progressive stroke, and crescendo transient ischemic attacks were 56.3, 76.4 and 80.9%, respectively; the combined major stroke/mortality rates (Rankin 4-6) were 43.7, 23.6 and 19.1%, respectively. Intraoperative angiography in 39 patients detected early carotid reocclusions in 2 and intracranial embolism in 7 patients. Local application of thrombolytic agents (n = 5) may contribute to a better neurological outcome in emergency CEA. Life table probabilities of major strokefree survival were 74.5, 71.6, and 53.7% after 1, 2, and 5 years, respectively (including perioperative strokes). Life table probabilities to suffer no stroke recurrence during follow-up were 96.7, 96.7 and 85.3%, respectively (perioperative strokes excluded).

CONCLUSIONS

Emergency CEA may be worthwhile in selected patients. Completion angiography is mandatory. Emergency CEA should be included in therapeutic strategies for ischemic stroke.

Adult posttraumatic osteomyelitis of the tibial diaphysis of the tibial shaft

Osteomyelitis of the diaphysis of the tibia in adults is an uncommon but disabling condition. It occurs principally in patients with complex fractures of the tibial shaft in which devitalized bone becomes infected either with a single strain of a virulent organism or with multiple organisms. The outcome of treatment depends on the assessment and management of three interrelated factors, which are the vitality and stability of the bone, the virulence and antibiotic susceptibility of the infecting organism, and the condition of the soft tissues. The impact of the infection on the patient's vitality is of great importance. Successful management depends on control of inflammation, excision of dead bone, and stabilization of the skeleton. Interlocking nailing and local antibiotic treatment are particularly successful strategies. In the future, modification of the inflammatory response with local tissue mediators may become an important adjunctive therapy.

[Computer-based training exemplified by the carotid artery]

The purpose of computer-based training (CBT) is interactive use of multimedia components, such as text, graphics, animation, sound, digital slide shows, and videos. This CD-ROM illuminates different aspects of carotid surgery: cerebrovascular insufficiency, sonographic and neuroradiological diagnostics, indications and results of carotid surgery in the literature, perioperative complications and new developments such as interventional procedures. Digital imaging (60 minutes of video sequences and 250 graphics) especially focus on operative standard procedures (conventional and eversion technique) and alternative methods. CBT is an evolving supplement to improve education programs in vascular surgery.

Regional intestinal blood flow and nitric oxide synthase inhibition during sepsis in the rat

OBJECTIVE

Regional circulatory changes in intestinal mucosa were evaluated after the onset of septic shock and the effect of nitric oxide (NO) inhibition on mucosal blood flow was investigated at different locations along the intestine.

SUMMARY BACKGROUND DATA

The response of intestinal blood flow to different physiologic and pharmacologic stimuli is known to vary along the intestine, but limited data are available on regional alterations in intestinal blood flow during septic shock. These regional variations in intestinal blood flow could become important because NO inhibition might restore the circulation of one segment of the gut or exacerbate ischemia that may be occurring concomitantly in another segment of the intestine.

METHODS

Mucosal blood flow was studied with fluorescent microspheres in conscious unrestrained rats before and 2, 4, and 6 hours after lipopolysaccharide (LPS, 20 mg/kg intraperitoneally) induced sepsis in the presence and absence of the nitric oxide synthase inhibitor N(G)-nitro-L-argininemethylester (L-NAME, 5 mg/kg subcutaneously).

RESULTS

Control mucosal blood flow was significantly higher in the ileum than in the duodenum, jejunum, or colon. During LPS-induced sepsis, mucosal blood flow to the ileum decreased and perfusion to the remaining gut was preserved. This was accompanied by hypotension throughout the experiment. L-NAME administration during sepsis prevented hypotension and decreased mucosal blood flow to all segments of small intestine at 2 hours. In this group, mucosal blood flow to the proximal small intestine but not to the ileum returned to baseline levels at 4 and 6 hours. L-NAME alone decreased mucosal blood flow to the small intestine throughout the experiment.

CONCLUSIONS

This study indicates that mucosal blood flow alterations during septic shock vary along the intestine, with a significant change only in the ileum, suggesting that perfusion in the small intestine is dependent on physiologic NO production.

Hypotension during septic shock does not correlate with plasma levels of nitric oxide metabolites in the conscious rat

Hypotension following administration of lipopolysaccharide may be due to excessive production of the potent vasodilator nitric oxide brought about by induction of nitric oxide synthase. The purpose of this study was to determine in conscious, fasted rats what role nitric oxide played in lipopolysaccharide-induced hypotension. When examined by Western immunoblot analysis, inducible nitric oxide synthase immunoreactivity was detected in the aorta at 3 hours and increased over time following administration of intraperitoneal lipopolysaccharide (20 mg/kg). When compared with saline-treated control rats, significant hypotension was observed at 2, 4, and 6 hours following lipopolysaccharide treatment. Blood pressure at 2 hours did not differ significantly from that at 6 hours. Using the Griess reaction to quantify plasma levels of nitrates and nitrites as an index of systemic nitric oxide production, an augmentation in the formation of these nitric oxide metabolites was demonstrated at 4 and 6 hours but not at 2 hours. Subcutaneous administration of the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (5 mg/kg) prevented lipopolysaccharide-induced hypotension, an effect reversed by subcutaneous L-arginine but not D-arginine (350 mg/kg). However, nitric oxide synthase inhibition did not attenuate the ability of lipopolysaccharide to increase plasma nitrate/nitrite levels. These data indicate that lipopolysaccharide-induced production of nitric oxide metabolites does not correlate with lipopolysaccharide-induced hypotension.

Cholecystokinin-induced protection against gastric injury is independent of endogenous somatostatin

Cholecystokinin (CCK) prevents macroscopic injury to the stomach from luminal irritants by an unknown mechanism. The present study was undertaken in conscious rats to ascertain what role gastric mucosal blood flow, sensory neurons, and endogenous somatostatin play in CCK-induced gastric protection. Subcutaneous administration of CCK (10-100 micrograms/kg) significantly reduced macroscopic injury to the acid-secreting portion of the stomach caused by 1 ml of orally administered acidified ethanol (150 mM HCl, 50% ethanol) and augmented gastric mucosal blood flow (fluorescent microspheres) in a dose-dependent fashion. However, although the protective response to CCK (100 micrograms/kg) was still present at 2 h, the blood flow response had returned to baseline by 45 min. Ablation of capsaicin-sensitive afferent neurons with capsaicin (125 mg/kg sc) did not negate CCK-induced protection. Pretreatment with exogenous somatostatin (1 pmol-1 nmol/kg sc) failed to prevent the damaging effects of acidified ethanol to gastric mucosa. Immunoneutralization of endogenous somatostatin with somatostatin monoclonal antibody (2 mg ip) did not reverse the protective actions of CCK. Thus the data suggest that although CCK may prepare the gastric mucosa to withstand a damaging insult by augmenting gastric mucosal blood flow, its protective mechanism is independent of intact sensory neurons and endogenous somatostatin.

Effects of the selective bisindolylmaleimide protein kinase C inhibitor GF 109203X on P-glycoprotein-mediated multidrug resistance

Inhibition of protein kinase C (PKC) is discussed as a new approach for overcoming multidrug resistance (MDR) in cancer chemotherapy. For evaluation of this concept we applied the bisindolylmaleimide GF 109203X, which shows a highly selective inhibition of PKC isozymes alpha, beta 1, beta 2, gamma, delta and epsilon in vitro. The efficacy of this compound in modulation of MDR was examined using several P-glycoprotein (P-gp)-overexpressing cell lines including a MDR1-transfected HeLa clone, and was compared with the activities of dexniguldipine-HCI (DNIG) and dexverapamil-HC1 (DVER), both of which essentially act via binding to P-gp. As PKC alpha has been suggested to play a major role in P-gp-mediated MDR, cell lines exhibiting different expression levels of this PKC isozyme were chosen. On crude PKC preparations or in a cellular assay using a cfos(-711)CAT-transfected NIH 3T3 clone, the inhibitory qualities of the bisindolylmaleimide at submicromolar concentrations were demonstrated. At up 1 microM final concentrations of the PKC inhibitor GF 109203X, a concentration at which many PKC isozymes should be blocked substantially, no cytotoxic or MDR-reversing effects whatsoever were seen, as monitored by 72 h tetrazolium-based colorimetric MTT assays or a 90 min rhodamine 123 accumulation assay. Moreover, depletion of PKC alpha by phorbol ester in HeLa-MDR1 transfectants had no influence on rhodamine 123 accumulation after 24 or 48 h. MDR reversal activity of GF 109203X was seen at higher final drug concentrations, however. Remarkably, [3H]vinblastine-sulphate binding competition experiments using P-gp-containing crude membrane preparations demonstrated similar dose dependencies as found for MDR reversion by the three modulators, i.e. decreasing efficacy in the series dexniguldipine-HCl > dexverapamil-HCl > GF 109203X. Similar interaction with the P-gp in the micromolar concentration range was revealed by competition of GF 109203X with photoincorporation of [3H]azidopine into P-gp-containing crude membrane preparations. No significant effect of the PKC inhibitor on MDR1 expression was seen, which was examined by cDNA-PCR. Thus, the bisindolylmaleimide GF 109203X probably influences MDR mostly via direct binding to P-gp. Our work identifies the bisindolylmaleimide GF 109203X as a new type of drug interacting with P-gp directly, but does not support the concept of a major contribution of PKC to a P-gp-associated MDR, at least using the particular cellular model systems and the selective, albeit general, PKC inhibitor GF 109203X.

Secondary interlocking nailing of previously infected nonunion of the tibia

Secondary interlocking nailing was performed in a series of 25 cases of uninfected, but previously infected nonunion of the tibia because of delayed bone consolidation or persisting nonunion. The primary treatment for the originally infected nonunion consisted of radical debridement, removal of alloplastic implants and sequestrated bone fragments, implantation of Gentamicin-PMMA chains(1) for local antibiotic therapy, re-osteosyenthesis with an external fixator. Bone grafting was performed after eradication of the infection. In two patients free muscle transfer with microvascular anastomosis became necessary to improve the soft tissue situation before bone grafting. Gentamicin-PMMA sticks with antibiotic activity similar to the Gentamicin-PMMA chains were inserted into the lumen of the nails as a prophylactic measure to prevent reinfection after nailing.

RESULTS

In 22 patients complete bone consolidation was achieved without recurrence of infection. In two patients with late recurrence of infection but incomplete bone consolidation, the implant was removed and an orthopaedic brace was applied temporarily. In one patient with early recurrence of infection with a highly resistant strain of Staph. aur. removal of the nail became necessary, followed by re-osteosyenthesis with an external fixator, systemic antibiotic therapy and secondary bone grafting.

A flow sheet for follow-up after chemotherapy extravasation

PURPOSE/OBJECTIVES

To introduce and describe the development and implementation of a flow sheet used to document patient follow-up after chemotherapy extravasation.

DATA SOURCES

Published articles, institutional standards of nursing practice, and the Oncology Nursing Society Cancer Chemotherapy Guidelines.

DATA SYNTHESIS

Extravasation is a potentially serious and severe complication of vesicant chemotherapy administration. A tool was designed to streamline documentation of patient symptoms, nursing interventions, patient education, and follow-up care after a suspected or actual extravasation.

CONCLUSIONS

The flow sheet improves nursing documentation after a suspected or actual vesicant chemotherapy extravasation and provides a consistent, concise method for monitoring extravasations over time.

IMPLICATIONS FOR NURSING PRACTICE

The flow sheet standardizes nursing assessment, intervention, patient education, and follow-up care after a suspected or actual chemotherapy extravasation. Use of the flow sheet saves time and improves consistency of nursing documentation.

B9209-005, an azido derivative of the chemosensitizer dexniguldipine-HCl, photolabels P-glycoprotein

P-glycoprotein is an energy-dependent drug extrusion pump for a variety of anticancer drugs and is involved in the development of multidrug resistance in cancer. Dexniguldipine-HCl is a potent chemosensitizer for P-glycoprotein-mediated multidrug resistance in vitro, and clinical phase I/II trials are underway. To investigate the mechanisms of chemosensitization and to identify the binding sites for dexniguldipine-HCl on target proteins involved in chemosensitization, [3H]B9209-005, an azido derivative of dexniguldipine-HCl, was synthesized and used as a photoaffinity ligand. In two models of multidrug resistance reversal, i.e., sensitization to vincristine and modulation of rhodamine-123 uptake, B9209-005 and dexniguldipine-HCl showed identical biological activities. Photoaffinity labeling experiments with [3H]B9209-005 in cell membranes from multidrug-resistant CCRF ADR-5000 cells, in comparison with labeling experiments with [3H]azidopine (an established photoaffinity ligand for P-glycoprotein), showed that [3H]B9209-005 labeled two proteins, with apparent molecular masses of 170 and 95 kDa. The pharmacological specificity of labeling was demonstrated by inhibition of photoincorporation by several cytostatic drugs transported by P-glycoprotein, as well as by chemosensitizers. Immunoprecipitation of the labeled proteins with the P-glycoprotein-specific monoclonal antibody C 219 and with a site-directed polyclonal antibody to the amino-terminal sequence of P-glycoprotein (amino acids 389-406) identified these proteins as intact P-glycoprotein and the amino-terminal fragment thereof. No specific labeling was obtained in the drug-sensitive parent cell line CCRF-CEM, which is devoid of significant P-glycoprotein expression. Maximal labeling of 17 pmol of the 170-kDa protein/mg of crude membrane protein was obtained. The affinity of [3H]B9209-005 for binding to and photoincorporation into P-glycoprotein was 5-fold greater than that of [3H]azidopine, and photoincorporation of [3H]B9209-005 showed a different photoincorporation pattern, compared with [3H]azidopine, in that the latter compound was incorporated specifically into the carboxyl-terminal 55-kDa fragment of P-glycoprotein. In contrast to [3H]azidopine, no specific labeling of this fragment was obtained with [3H]B9209-005, indicating different binding sites for or different photoincorporation of the two dihydropyridine ligands. Because B9209-005 carries the photoreactive azido group in the dihydropyridine moiety, whereas the azido group of azidopine is located in the side chain, these results suggest that the dihydropyridine moiety of the two compounds probably interacts with the amino-terminal part of P-glycoprotein, whereas the side chains react preferentially with the carboxyl-terminal 55-kDa fragment.(ABSTRACT TRUNCATED AT 400 WORDS)

Hemorrhagic shock increases gut macromolecular permeability in the rat

The effect of hemorrhagic shock on gut permeability to macromolecules was investigated using fluorescein isothiocyanate dextrans (4,300 or 73,100 daltons). These were given orally, then measured in systemic blood during hemorrhage (mean arterial pressure of 30 mmHg) and reperfusion; sham-shocked animals served as controls. Hemorrhage lasting 2 h resulted in a 5-fold increase in concentration of both tracers relative to that found in control groups. Reperfusion reduced these differences, with values approximately threefold greater than those of controls after 2 h. On a molar basis, the smaller molecule was more permeant than the larger one. This study provides evidence that hemorrhagic shock physically perturbs the normal barrier function of the mucosa, permitting very large substances in the gut lumen access to the circulation. It may further explain, at least in part, previous observations that hypovolemic shock results in bacterial translocation and endotoxemia.

Use of antibiotic-PMMA beads in the ischemic foot

Thirty-six patients with 44 ischemic foot infections were managed with antibiotic-polymethylmethacrylate (PMMA) beads. Most of these patients received gentamicin-impregnated PMMA beads but tobramycin and vancomycin-impregnated PMMA beads were used on three patients. Angiopathy occurred in 35 patients secondary to diabetes and secondary to renal disease in 2; 1 patient had both diabetes and renal disease. The most common bacteria was Staphylococcus aureus (82%), although other organisms and multiple bacteria were present. In spite of the variability of the bacteria, PMMA beads were helpful in managing foot infections in this difficult patient population.

Primary structure differences of human surfactant-associated proteins isolated from normal and proteinosis lung

The primary structures of human pulmonary surfactant-associated proteins SP-A, SP-B and SP-C isolated from lung lavage of patients with alveolar proteinosis exhibit significant differences from lung surfactant proteins isolated from lungs of healthy individuals. In contrast to SP-A from normal lungs, proteinosis SP-A was shown by SDS gel electrophoresis to contain large amounts of unreducibly cross-linked beta chains. Specific primary structure modifications of SP-C and SP-B proteins were established by direct molecular weight and structural analysis, using [252Cf]plasma desorption mass spectrometry (PD/MS) as the principal method. In comparison to normal lung surfactant SP-B, proteinosis SP-B showed a significantly increased molecular weight by approx. 500 Da for the unreduced protein dimer. SP-C proteins from normal lungs were identified to possess a bis-cysteinyl-5,6-(thioester)palmitoylated structure, and to contain a frayed N-terminus resulting in two sequences of 34 and 35 amino acid residues. In contrast, SP-C from proteinosis patients was modified by (i) partial or even complete removal of palmitate residues and (ii) additional N-terminal proteolytic degradation. These results indicate the presence of pathophysiological structure modifications, which are likely to occur in the alveolar space, and may lead to a reduced surfactant function.

(H+,K+)-ATPase inhibiting 2-[(2-pyridylmethyl)sulfinyl]benzimidazoles. 4. A novel series of dimethoxypyridyl-substituted inhibitors with enhanced selectivity. The selection of pantoprazole as a clinical candidate

[(Pyridylmethyl)sulfinyl]benzimidazoles 1 (PSBs) are a class of highly potent antisecretory (H+,K+)-ATPase inhibitors which need to be activated by acid to form their active principle, the cyclic sulfenamide 4. Selective inhibitors of the (H+,K+)-ATPase in vivo give rise to the nonselective thiophile 4 solely at low pH, thus avoiding interaction with other thiol groups in the body. The propensity to undergo the acid-catalyzed transformation is dependent on the nucleophilic/electrophilic properties of the functional groups involved in the formation of 2 since this step is both rate-determining and pH-dependent. The aim of this study was to identify compounds with high (H+,K+)-ATPase inhibitory activity in stimulated gastric glands possessing acidic pH, but low reactivity (high chemical stability) at neutral pH as reflected by in vitro (Na+,K+)-ATPase inhibitory activity. The critical influence of substituents flanking the pyridine 4-methoxy substituent present in all derivatives was carefully studied. The introduction of a 3-methoxy group gave inhibitors possessing a combination of high potency, similar to omeprazole and lansoprazole, but increased stability. As a result of these studies, compound 1a (INN pantoprazole) was selected as a candidate drug and is currently undergoing phase III clinical studies.

[Closure of soft tissue defects in bone infections using free and pedicled muscle flaps]

Over the period of three years 33 free latissimus dorsi-flaps and 23 pedicled myoplasties of various types for the coverage of large tissue and bone defects are performed. The operative technique of the free muscle transfer with microvascular anastomosis are described in detail. The postoperative management is outlined. The results of the free and pedicled muscle flaps are reported. In free transplantations the success-rate was 88% and in pedicled flaps 65% There is good evidence that bone consolidation and healing of the chronic bone infection can be improved by healthy vital soft tissue coverage. The indications for both procedures and the advantages and disadvantages of free and pedicled flaps are discussed.

[The social environment and consequences in patients with posttraumatic osteomyelitis]

As soon as the extent of damage--especially in infected nonunion with substantial bone defect--becomes clinically apparent, the patient should be fully informed about the possibilities of treatment, which functional result can be expected in an attempt to salvage the extremity and the implications of long-term hospitalization with the necessity for multiple operations on the patient's social and professional rehabilitation. The patient may then decide for himself that early amputation will give him much better chances in his future life.

[Treatment of chronic osteomyelitis with gentamicin PMMA chains]

In the treatment of chronic osteomyelitis radical removal of sequestrated bone fragments is of essential importance. Any antibiotic therapy - whether systemically or locally applied - can only be a supplementary measure. By implantation of gentamicin-PMMA-chains into infected cavities high local concentrations of the antibiotic can be achieved which are far above the minimal bactericidal concentrations of most common pathogens. As result of the very low concentrations of gentamicin in the serum and urine there is no hazard of nephrotoxicity and ototoxicity. Chronic sequestrating osteosyntheses and infected non-unions are the most important indications for the application of gentamicin-PMMA-chains.

The sulphoxide moiety of substituted benzimidazoles is essential for inhibition of parietal cell K+/H+-ATPase

The antisecretory action of the benzimidazole sulphoxide derivative B 823-10, 2[(4-methoxy-3-methyl-2-pyridylmethyl)-sulphinyl]- 5-trifluoromethyl(1H)-benzimidazole, was compared with the effect of the corresponding sulphide B 823-08 in several in vivo and in vitro and in vitro test systems. The sulphide B 823-08 and the sulphoxide B 823-10 were found to be equipotent in the Shay rat. The sulphide was found to inhibit H+ secretion in intact rabbit gastric glands and enriched guinea-pig parietal cells with lower potency than the corresponding sulphoxide. The relative potency in antisecretory activity (sulphide/sulphoxide) decreased in the following rank order: Shay rat: gastric glands: parietal cells. Purified K+/H+-ATPase was not blocked by the sulphide, whereas the sulphoxide inhibited the overall as well as the partial reactions of this enzyme. In all in vitro systems tested, inhibition of H+ secretion and enzyme activity by the sulphoxide, but not by the sulphide, was antagonized by SH-compounds such as dithiothreitol. It is concluded that in vivo sulphoxidation of the sulphide plays an important role in acid inhibition. In vitro an additional inhibitory mechanism of the sulphide has to be considered.

Dipeptidyl peptidase IV and alpha-naphthylacetate esterase in human T lymphocytes: cytochemical and biochemical investigations

Dipeptidyl peptidase IV (DP IV) activity of human lymphocytes was measured using biochemical assays of cell suspensions and enzyme cytochemical staining of smears from capillary blood and mononuclear cells (MNC). The hydrolysis rate of Gly-Pro-pNA in suspensions of MNC correlates well with the number of DP IV reactive cells as determined by cytochemical staining. MNC from healthy volunteers were shown to contain 44 +/- 10% lymphocytes reactive for DP IV. Using preparations of T lymphocytes and adherent MNC it was shown that DP IV is specific for T lymphocytes. About 60% of T lymphocytes contain DP IV and 94% of DP IV reactive cells form rosettes with sheep erythrocytes. Parallel staining for DP IV and unspecific acid alpha-naphthylacetate esterase (ANAE) yielded nearly the same figure of cells stained for ANAE in a dot-like pattern (50 +/- 10% MNC) as was observed for DP IV. Correlation of both markers indicates that DP IV expressing lymphocytes presumably represent that subpopulation of TM cells which is characterized by a dot-like reaction pattern of ANAE.

[Indication, technic and results using the external fixator in infected fractures and infected pseudarthrosis]

Infected pseudo-arthrosis is the dreaded combination of chronic osteomyelitis and instability at the fracture site. Treatment consists in radical removal of sequestered bone and alloplastic implants, temporary implantation of Septopal chains for high-dose local antibiotic therapy and re-osteosynthesis with external fixator. The external fixator of Raoul Hoffmann is preferred because of its unlimited versatility. A total of 131 patients were treated in accordance with the method described. In 90.1% of the cases bone consolidation was achieved, and in 89.3% chronic osteomyelitis subsided.

[The fall of Icarus or the seriously injured young motorcyclist (author's transl)]

During 1979 70 motorcyclists were treated in the Department of Traumatology of the "Berufsgenossenschaftliche Unfallklinik" Frankfurt/Main. The psychological reasons of the motorcycle-boom and the consequences are compared. The psychic status of these young motorcyclists was different from that of other patients. An analysis of the data showed that in 24.3% the accident occurred on the way to work or to school; 75.7% of the accidents happened during a pleasure-trip. 58.6% of the motorcyclists suffered injuries with permanent sequels. The different types of permanent damage are described. Based on two case reports the arising costs are analysed.