Biomedical subjects
Publications and source records attributed to G Weiss.
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AIM: The correlation between improved cementing techniques and improved long-term results after total hip arthroplasty (THA) is well documented. The purpose of this study was to assess the use of modern cementing techniques in Germany. METHODS: A detailed questionaire regarding cement and bone preparation, cementing techniques on actabulum and femur, and implants used was sent to 584 German orthopaedic and trauma hospitals, as well as to visiting surgeons with an interest in THA. In total, 333 questionaires were available for evaluation and statistical analysis. RESULTS: In this survey, Palacos bone cement is used in 84%, low viscosity cement in 9%. Cement chilling is performed in 58%. Mixing is done by hand without vacuum mixing systems in 53%, the mixing time is standardised in 66%. For the femur 83% and for the acetabulum 74% preserve cancellous bone, 13% use pulsed lavage. Cement application is done via cement gun in 97%, in 41% in a retrograde manner and in 18% without drainage of the intramedullary canal. A cement pressurising technique is used in 63% for the femur and in 57% for the acetabulum. A cement mantle of less than 2 mm is attempted in 41%. More than 50 different stem design are implanted with the Müller straight stem being used most often, followed by anatomic designs. Almost 50% of hips are used with a 28 mm head, and almost 50% are implanted with a 32 mm head. Half the heads are ceramic, half are metal. CONCLUSIONS: The results from this survey document, that overall only slightly more than 10% of hips are implanted using second/third generation (modern) cementing techniques with application of pulsed lavage. This has implications on the number of arthroplasties that may require revision. From the data available the current status of cementing technique in Germany cannot be judged satisfactory.
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Microencapsulation of the renin inhibitor FK906 (tripeptide) by phase separation of ethylcellulose in cyclohexane was performed to obtain sustained release of the drug for a once-a-day application. Owing to the binding characteristics and to the very low solubility of FK906 in cyclohexane, microencapsulation can be performed after granulation of the drug with an inert filler, and no additional binder is required. Microcapsules with a particle size of 180-590 microns are obtained in a yield of 70%. Drug content determinations and SEM-micrographs reveal the almost complete incorporation of the polymer for the coating and the high quality of the microcapsule wall. Despite the strongly pH-dependent solubility of FK906 (.HCl) in water, the microcapsules show almost identical sustained-release curves at pH 1.2 and 6.0 (0.05 M phosphate buffer). This is explained by an acidic microenvironment inside the microcapsules at both pHs investigated and was attributed to the intrinsic physico-chemical properties of FK906 which help to overcome the buffer capacity of the phosphate buffer, pH 6.0, inside the microcapsules. This theory was confirmed by solubility experiments at pH 6.0 using excess amounts of FK906 as well as by dissolution tests as a function of the buffer capacity and the osmolality of the dissolution medium. The buffer capacity was found to be the parameter with greater influence on the release rate.
OBJECTIVE: The risk of spontaneous preterm birth has been related to decreased cervical length and to increased serum relaxin. To explore a relationship between these findings, we used data collected from two prior studies to correlate relaxin levels with cervical length and risk of spontaneous preterm birth in women with twin pregnancies. METHODS: In a secondary analysis of data collected in two previous observational studies of risk factors for preterm birth, relaxin levels in maternal serum and cervical length were measured at 24 (n= 188) and 28 (n= 145) weeks in women with spontaneous twin pregnancies. Relaxin, as a continuous variable, was related by logistic regression analysis to risk of spontaneous preterm birth before 37, 35, and 32 weeks' gestation, and by Spearman correlation coefficients to cervical length at 24 and 28 weeks. Cervical length at 24 weeks was known to be correlated with spontaneous preterm birth before 37, 35, and 32 weeks (P =.03,.01, and.002, respectively) in this study population. RESULTS: Cervical length did not correlate with relaxin levels at 24 (P=.601) or 28 (P=.304) weeks. Relationships between relaxin and spontaneous preterm birth were observed at 24 weeks for births before 37 weeks (odds ratio [OR] 1.56, 95% confidence interval [CI] 1.00, 2.44; P=.05), and at 28 weeks for births before 35 weeks (OR 1.97, 95% CI 1.05, 3.70; P=.034) and 32 weeks (OR 2.43, 95% CI 1.01, 5.83; P=.048). CONCLUSION: The absence of an association between relaxin and cervical length suggests that increased relaxin does not explain the inverse correlation between cervical length and spontaneous preterm birth in women with spontaneous twin pregnancies.
OBJECTIVES: Treatment with interferon (IFN) reduces viral replication and normalizes aminotransferase levels in a significant percentage of patients with non-A, non-B hepatitis or hepatitis C. Soluble immune activation markers were evaluated in patients with hepatitis. PATIENTS AND METHODS: Serum concentrations of soluble immune activation markers neopterin and beta 2-microglobulin (B2M) were compared to endogenous IFN-gamma levels in 17 patients with chronic hepatitis C before, during and after 9-months of treatment with IFN-alpha 2b. RESULTS: Before therapy some patients had increased concentrations of the studied variables. During therapy neopterin and B2M concentrations further increased whereas IFN-gamma decreased. IFN-gamma and neopterin levels were correlated before but not during therapy. The correlations between neopterin and B2M were significant throughout the study. CONCLUSION: The data indicate that IFN-gamma decreases during treatment and IFN-alpha 2b appears to enhance formation of neopterin and B2M.
Podiatric physicians must realize that the presence of crepitus, and/or radiographic evidence of gas in the subcutaneous tissue, does not necessarily mean anaerobic clostridial gas gangrene. This is especially true in the diabetic where other gas producing organisms have been isolated. The authors provide a literature review, and case study, of nonclostridial gas gangrene.
Methods for the analysis of polyether antibiotics in animal tissues and fluids are described. For monensin and nigericin, only methods based on bioautography are available. For lasalocid, in addition to TLC bioautography for quantitation in chicken skin and fat, LC methods based on fluorescence detection have been developed for quantitation in animal blood, milk, liver, skin, and fat. In addition, a confirmatory method for lasalocid is described; this is based on purification by LC followed by silylation and pyrolysis gas chromatography-positive chemical ionization mass spectrometry.
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This study was undertaken to determine whether present regulations for discarding milk from cows treated with sulfadimethoxine (SDM) can be supported by modern analytical methodology. Two groups of milking cows (10 in first group; 11 in the second) were treated orally with SDM at the recommended dose levels for 5 days. The SDM concentration in the milk was determined with 4 methods (Charm Inhibition Assay [CIA], Charm II, enzyme linked immunosorbent assay, and liquid chromatography) during the treatment and the subsequent withdrawal periods. The results of the 4 assays were compared.
PURPOSE: A phase II trial of outpatient subcutaneous (SC) interleukin-2 (rIL-2) plus interferon-alpha (IFN-alpha 2B) was performed in patients with metastatic renal cell cancer. A 5-year follow-up of that Cytokine Working Group study is presented. PATIENTS AND METHODS: Forty-seven patients meeting eligibility criteria of previous Cytokine Working Group studies were treated on an outpatient basis with SC rIL-2 (Chiron, Emeryville, CA), 5 x 10(6) IU/m2/dose q 8 hr x 3, then daily, 5 days per week, and IFN-alpha 2B (Schering-Plough, Kenilworth, NJ), 5 x 10(6) IU/m2/dose three times weekly for 4 weeks. After a 2- to 4-week break, patients were scheduled to continue treatment for up to six cycles. RESULTS: There were two complete and six partial responders (17% response rate, 95% CI: 8%-31%). Median duration of response was 12 months (range 1-49+ months), with complete responses of 15 and 49+ months. Responding sites of disease included lung, nodes, soft tissue, bone, and liver. Dose and schedule were adjusted to control toxicity at grade 2/3 levels, with 50% requiring dosage alterations. Grade 2/3 toxicity included fatigue, nausea/vomiting, diarrhea, anorexia, fluid overload, rash, CNS, injection site pain, chest pain/palpitations (including atrial fibrillation requiring treatment, two patients), and hypotension. Grade 4 toxicity included dehydration (seven patients), vomiting (one patient), and irreversible renal failure with crescentic glomerulonephritis requiring dialysis (one patient). CONCLUSION: SC rIL-2 plus IFN-a2B is tolerated in the outpatient setting with frequent dose adjustments. The overall response rate of this regimen is similar to that seen with high-dose rIL-2 alone; however, the response duration appears to be shorter.
OBJECTIVE: To investigate the effects of dialysis procedures on cardiac diastolic function. DESIGN: Comparative, nonrandomized matched pair study. SETTING: Nephrology and cardiology departments at a university hospital. PATIENTS: Thirty-four patients on hemodialysis (HD) (n = 17) and continuous ambulatory peritoneal dialysis (CAPD) (n = 17), matched by sex, age, duration of dialysis treatment, and presence/absence of diabetes. MEASUREMENTS: Cardiac function was estimated by means of M-mode, two-dimensional, and spectral Doppler echocardiography, and results were statistically evaluated by means of univariate and multivariate analytical procedures. RESULTS: Although not statistically significant, trends towards differences between the two patient groups were detected for left ventricular mass (p = 0.083) and parameters of diastolic function (p = 0.079). These differences in left ventricular performance and diastolic function between HD and CAPD patients were also evident when calculating Spearman rank correlation coefficients. Left ventricular mass and diastolic function were closely correlated to each other in all dialysis patients. Moreover, by means of a multivariate analytical procedure (Hotelling T-square test), diversities in diastolic function between the two patient groups could be clearly established (p = 0.037), with more impaired diastolic function in HD patients. In addition, cardiac performance was shown to depend to a certain extent on hemoglobin concentration. CONCLUSION: Clear differences in diastolic function and cardiac performance were evident between CAPD and HD patients. From the data of our pilot study, it may be speculated whether decrease of left ventricular mass could be beneficial for the improvement of diastolic function and cardiac hemodynamics in dialysis patients.