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Biomedical subjects

M Wolf

Publications and source records attributed to M Wolf.

At least 253 records · Page 14Linked to original sources
PubMed1996

Improved monitoring of preterm infants by Fuzzy Logic.

Keeping the oxygenation status of newborn infants within physiologic limits is a crucial task in intensive care. For this purpose several vital parameters are supervised routinely by monitors, such as electrocardiograph, transcutaneous partial oxygen pressure monitor and pulse oximeter. Each monitor issues an alarm signal whenever an upper or lower limit of the parameter(s) measured is exceeded. However, in practice it turns out, that a considerable amount of false alarms is generated by artefacts, which are attributed mostly to movements of the infants. Eliminating these false alarms would be of benefit to the staff as well as the patients of the intensive care unit. Accordingly, an automated system based on Fuzzy Logic was developed, which is capable of distinguishing between critical situations and artefacts. The system is based on a Transputer IMS T425 in a PC, which collects the data from the monitors, plots it on a colour screen, saves it to hard disk and analyses it by Fuzzy Logic. Fuzzy algorithms were developed to generate more reliable alarms. All vital parameters of eight infants, who either moved often and/or frequently produced real alarm situations, were recorded. Synchronously the infants' movements and care procedures were video taped. The data and video were analysed off line with the help of an experienced neonatologist. His judgement was compared to the analysis of the Fuzzy Logic system. The results show that it is possible to improve the reliability of the monitored data with the aid of an evaluation strategy based on Fuzzy Logic and hence distinguish between real alarm situations and movement artefacts to the extent that an application in an intensive care unit under routine conditions becomes conceivable.

Algorithms↗
PubMed1996

Paclitaxel and simultaneous radiation in the treatment of stage IIIA/B non-small cell lung cancer.

In a clinical phase II trial, escalating doses of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) were given with concurrent radiation to patients with stage IIIA/B non-small cell lung cancer. Radiotherapy was given in daily doses of 2 Gy, 5 days a week, in weeks 1 through 3 and 6 through 8. Paclitaxel was given on day 1 of weeks 1 through 3 and 6 through 8, at a starting dose level of 50 mg/m2. Subsequent paclitaxel dose levels were 60, 72, 86, and 103 mg/m2. Three to six patients were included at each dose level until intolerable toxicity (World Health Organization grade 3 or 4 leukopenia) occurred in three of six patients. To date, 27 patients have entered the protocol. Hematologic toxicity was mild with no severe myelosuppression up to the 86-mg/m2 dose level. At paclitaxel 103 mg/m2, four of six patients developed grade 3 or 4 leukopenia, and dose escalation was stopped. The maximum tolerated dose was thus determined to be 86 mg/m2. The main clinical toxicity was the occurrence of pulmonary infections (seven patients), one of whom had Pneumocystis carinii infection; the six others had interstitial infections with no pathogen isolated. Mild to moderate esophagitis was seen in five patients. Thus far, of 24 patients evaluable for response, 18 showed decreased tumor size. Four patients achieved major responses (near-complete disappearance of radiologic tumor signs), 11 patients achieved partial remission, and three patients had a minor response. The overall response rate was 75%. In summary, the maximum tolerated dose of paclitaxel in this study has been determined to be 86 mg/m2 weekly. Pulmonary infections represent the major clinical toxicity, and the high response rate merits further clinical evaluation of this regimen.

Adult↗
PubMed1996

[Epidemiology of individual front tooth gaps in exiled Tamilians].

During the period from 1986 to 1993, 254 Tamilian patients were examined by the Department of Public Health at Wuppertal. These patients had come from Sri Lanka as refugees applying for political asylum in the Federal Republic of Germany. In more than 60% of the patients isolated front tooth gaps were observed, an incidence that was significantly higher than in a control group of asylum seekers from countries other than Sri Lanka, and much higher than the incidence of traumatic tooth loss reported in the literature. To the authors the aetiology of this tooth loss remains largely unexplained, since the bulk of the medical histories given by the patients did not correlate with clinical and x-ray evidence. Considering that medical and especially dental causes for the loss of the teeth can be excluded, social, cultural, religious, or even political causes may be responsible for this anomaly.

Adolescent↗
PubMed1995

Association of down-regulation of cytokine activity with rat hind limb allograft survival.

Cytokines are short-acting protein modulators of many physiologic processes including graft rejection. An understanding of the production, action, and interaction of cytokines may lead to better appreciation of the complex mechanism of graft rejection. The potential would then exist for more selective and less-toxic means of modulating the immune response. A rat hind limb allograft model with major immunohistoincompatibility was used to study the local mRNA expression of IL-1 alpha, IL-2, IL-6, gamma interferon (gamma INF), platelet-derived growth factor-alpha (PDGF-alpha), basic fibroblast growth factor (FGF), and transforming growth factor-beta (TGF-beta) during acute allograft rejection. A 14-day postoperative course of immunosuppressive therapy with FK506 or rapamycin was administered. In situ hybridization was performed on serial full-thickness skin punch biopsies of the untreated rejecting limb allograft and compared with tissue from treated allografts, isografts, and to normal limb tissue. A sequential pattern of cytokine mRNA expression was demonstrated which progressed in a time-dependent manner and paralleled observed clinical rejection. Maximal cytokine mRNA expression correlated with peak graft rejection. Cellular expression of IL-1 alpha, IL-2, IL-6, gamma-INF, FGF, and TGF-beta mRNA was suppressed with FK506 to below isograft levels, and clinical rejection was not observed with the doses, routes, and schedules used. Rapamycin was ineffective in suppressing cytokine expression, and allograft rejection was not prevented. Isografts demonstrated no evidence of rejection. The in situ hybridization technique demonstrates a time-dependent, selective expression of cytokines within rejecting allograft tissue, and the modification of this response with immunosuppressive therapy. Down-regulation of cytokine expression is associated with clinical allograft survival.

Animals↗
PubMed1995

The indication for tonsillectomy in children following peritonsillar abscess.

The clinical course of 19 consecutive children treated for peritonsillar abscess (PTA), in the Chaim Sheba Medical Center, between 1988-1992 was retrospectively reviewed. The abscess was drained through an incision (12 children) and by needle aspiration (7 children), under local (11 children) or general (8 children) anesthesia. One child suffered from recurrent bouts of tonsillitis after the abscess resolved and eventually underwent tonsillectomy. Two others, with a pre-PTA history of recurrent tonsillitis (T+) underwent interval tonsillectomy. Recurrent PTA did not develop in any of the 16 non-operated children. The involvement of mainly older children can explain both the low rate of the pre-PTA history of T+ and the number of children whose abscess could be drained under local anesthesia. Tonsillectomy should be indicated in cases of recurrent PTA or in children with a pre-PTA history of T+. The need for general anesthesia for draining the abscess in young children does not seem, in itself, to warrant a routine hot tonsillectomy.

Adolescent↗
PubMed1995

Acute suppurative parotitis and parotid abscess in children.

Acute suppurative parotitis and parotid gland abscess are infrequently encountered among children. Fourteen children were diagnosed in the Sheba Medical Center as suffering from these infections and their clinical features are described. Discussion reveals neither significant differences nor predominating factors to differentiate between these two entities.

Abscess↗
PubMed1995

Design of the Prostate Cancer Prevention Trial (PCPT).

The PCPT is a chemoprevention trial of finasteride with a primary endpoint of biopsy-proven presence or absence of prostate cancer. A total of 18,000 healthy men, aged 55 years and older, will be randomized. Half will receive finasteride (5 mg/day) and half will receive placebo (one matching tablet per day) for 7 years. The trial is designed to have 92% power to detect a 25% reduction in period prevalence of biopsy-proven disease using a two-sided test with alpha = 0.05. The trial is complicated by the known impact of finasteride on the major screening test for prostate cancer, prostate specific antigen (PSA). This paper describes the PCPT design with reference to alternatives that were considered. The chosen design depends on five critical assumptions that must be monitored closely throughout the 9-year trial.

Aged↗
PubMed1995

Evaluation of low dose alpha-interferon (Roferon-A) in patients with advanced renal cell carcinoma: a Southwest Oncology Group study.

Alpha-interferon (IFN) has been shown to produce antitumor responses among patients with advanced renal cell carcinoma. While responses have been observed over a range of IFN doses and schedules, significant toxicities can be experienced from relatively high doses given three to five times weekly. Based upon the report of a pilot study indicating that low dose daily IFN could produce antitumor responses with minimal toxicity, the Southwest Oncology Group investigated this schema in a phase II trial. Patients with bidimensionally measurable disease were treated with Roferon-A 1 million units subcutaneously daily and tumor assessments were conducted on a monthly basis. There were no dose escalations and no dose reductions for toxicity. The treatment was well tolerated with only two patients withdrawing from treatment because of side effects. Among 56 eligible patients treated, there were five partial responses and one complete response for an overall response rate of 11% (95% confidence interval, 4 - 22%). However, objective antitumor responses could not be determined for 16 of the 56 patients. Among the 40 fully evaluable patients the 6 objective responses yields a response rate of 15% (95% confidence interval, 5.7-30%). It is concluded that this dose and schedule of IFN has activity against advanced renal cell carcinoma. A randomized trial would be required to determine if this low dose regimen is as effective as the higher doses which have been used traditionally.

Adult↗
PubMed1995

Heterogeneity of DM kinase repeat expansion in different fetal tissues and further expansion during cell proliferation in vitro: evidence for a casual involvement of methyl-directed DNA mismatch repair in triplet repeat stability.

We have analysed the mitotic behaviour of expanded CTG repeats in somatic tissues and cultured somatic cells from myotonic dystrophy (DM) fetuses using indirect and direct methods. Heterogeneity of expansions between fetal tissues was demonstrated in a 16 week old fetus whereas there was no evidence for such a somatic heterogeneity in a 13 week old fetus. Dilution plating of cultured cells from an adult patient and a fetus resulted in isolation of clones showing single expanded restriction fragments when the donor showed a heterogeneous smear of expansions or a single expanded fragment. During proliferation in vitro to 45 doublings, DM cells experienced highly synchronous further repeat expansion which first became evident at approximately 15 cell generations and reached a plateau of maximum expansion at approximately 200 days. When mathematically expressed as a function of culture time the dynamics of expansion of restriction fragments followed a sigmoid curve. This unstable behaviour of CTG repeat expansions in DM was compared to the mitotically stable patterns of full mutation in fragile X fetal tissues and led to the hypothesis that methylation of CpGs within the repeat sequence is a stabilizing factor of largely expanded CGG and GCC repeats allowing for efficient methyl-directed strand-specific DNA mismatch repair.

Adult↗
PubMed1995

Genes encoding xylan and beta-glucan hydrolysing enzymes in Bacillus subtilis: characterization, mapping and construction of strains deficient in lichenase, cellulase and xylanase.

The gene encoding extracellular xylanase (xynA) was amplified as a 770 bp DNA fragment from Bacillus subtilis 168 chromosomal DNA by PCR. The genes encoding endo-beta-1,4-glucanase (eglS) and endo-beta-1,3-1,4-glucanase (bglS) were isolated from a genomic library of B. subtilis 168. The sequences of xynA and eglS were identical to those of the xylanase and cellulase genes from B. subtilis PAP115. Integrative plasmids containing DNA fragments with deletions in the coding region of the genes were constructed and used to replace the chromosomal eglS, bglS and xynA genes of B. subtilis 168. Strains without any detectable activity against xylan (Xyn-), carboxymethylcellulose (Egl-) or mixed linked beta-1,3-1,4-glucan (Egl- Bgl-) were obtained. The genes were mapped at 170 degrees (eglS), 175 degrees (xynA) and 340 degrees (bglS) on the B. subtilis chromosome.

Bacillus subtilis↗
PubMed1995

Clozapine treatment in Russia: a review of clinical research.

OBJECTIVE: This paper is intended to help American clinicians and investigators further their understanding of the clinical use of clozapine by reviewing experience with the drug in Russia, where it was introduced 17 years before it became available in the United States. METHODS: Key articles on clozapine from the Russian clinical research literature were reviewed by the first two authors, former Russian clinical investigators. The third author comments briefly about the implications of this work from a contemporary American perspective. FINDINGS AND CONCLUSIONS: The review found that although clozapine was not widely distributed in Russia, it was investigated at several large psychiatric research institutions and hospitals. It was not reserved for neuroleptic-resistant disorders but instead was used with some success as a first-line treatment in acute disorders. Although no controlled clinical trials were conducted, results of long-term outcome studies of treatment-resistant schizophrenia were largely in agreement with those of controlled trials and clinical follow-up studies in the U.S. The studies found short-term gains for previously refractory patients as well as improvements in social functioning that continued for extended periods in some cases. Russian investigators described clozapine as an effective antipsychotic agent that lacked the extrapyramidal side effects of other neuroleptics.

Clinical Trials as Topic↗
PubMed1995

Sucrose reduces pain reaction to heel lancing in preterm infants: a placebo-controlled, randomized and masked study.

In term infants sucrose given by mouth has been reported to reduce duration of crying after a heel prick. This study was designed primarily to investigate the effect of sucrose administered orally immediately before heel lancing on the nociceptive reaction in preterm infants as assessed by change in heart rate and duration of crying. A secondary objective was to document changes in cerebral blood volume during acute pain. We used a randomized, masked, placebo-controlled, crossover trial in a neonatal intermediate care unit in a level 3 perinatal center. The patients studied were 16 preterm infants; birth weight, 900-1900 g; gestational wk, 27-34; corrected postmenstrual age at time of investigation, 33-36 wk. Each infant was assessed twice receiving 2 mL of sucrose 50% or 2 mL of distilled water in random order immediately before heel lance. Heart rate, thoracic movements, and transcutaneous blood gases were monitored continuously. Crying during the procedure was documented by a video-camera. A change in cerebral blood volume was assessed by near-infrared spectroscopy. We found the heart increased by a mean of 35 beats/min (bpm) after sucrose and 51 bpm after placebo (median difference 16 bpm, interquartile range 1-30 bpm, p = 0.005). Infants cried 67% of time after sucrose and 88% after placebo (median difference 10%, interquartile range 3-33%, p = 0.002). Cerebral blood volume decreased in 5 of 14 infants after sucrose and in 6 of 14 infants after placebo (difference not significant).

Administration, Oral↗
PubMed1995

Visual field loss in senile dementia of the Alzheimer's type.

BACKGROUND: Visual performance is impaired in patients with senile dementia of the Alzheimer's type (SDAT). We investigated the visual field topography of these deficits. METHODS: Humphrey automated perimetry (Program 30-2) was used to measure differential luminance sensitivity within the central 60 degrees of the visual field in SDAT patients (n = 61) and in visually and cognitively normal volunteer subjects of similar age (n = 61). Twenty-three SDAT patients were retested 18 months after the original examination. RESULTS: Reliable visual fields (by manufacturer's criteria) were obtained in 72.1% (44/61) of the control subjects and 55.7% (34/61) of the SDAT group. In the SDAT group, differential luminance sensitivity was significantly reduced relative to the control group. Visual sensitivity was reduced throughout the visual field, but deficits were most pronounced in the inferior visual field, where they presented most commonly as arcuate defects. Patients with more severe dementia exhibited greater reductions in visual sensitivity. On follow-up, 14 of 23 SDAT patients exhibited progression of visual field loss, whereas only two of 23 patients exhibited a regression of the visual field loss. CONCLUSIONS: Although automated perimetry requires considerable patient cooperation, many patients with SDAT can produce reliable visual field results. These patients exhibit significant reductions in global sensitivity. Visual field loss in SDAT is most pronounced in the inferonasal and inferotemporal arcuate regions of the visual field but also involves the central field.

Aged↗
PubMed1995

Assessment of attenuated Salmonella typhimurium strains designed as potential carriers of foreign antigens for mucosal localization and immuno-genicity in a rabbit model.

Neither wild type nor attenuated S. typhimurium strains induced diarrheal illness in rabbits. All strains localized to the Peyer's patch at higher concentrations than in lumenal contents or adjacent ileum. Wild type S. typhimurium C5 induced a typhoid-like illness in rabbits with severe weight loss, bacteremia, persistent splenic colonization, and serum IgG response. Both attenuated strains were disseminated to spleen (day 3) but produced minimal systemic illness. They induced biliary IgA responses greater than the wild type (day 7), but minimal serum IgG responses. Both mutants of S. typhimurium are suitable for further development as live enteric vaccines to carry foreign antigens since they localize to Peyer's patch after oral inoculation, induce biliary antibody, and produce minimal systemic disease. The attenuated strains tested are systemically disseminated. It remains to be determined whether dissemination (determined by a large virulence plasmid) is necessary for the desired mucosal immune response or acceptable for an oral vaccine strain.

Administration, Oral↗
PubMed1995

[Gynecologic laparoscopy in sheep. 2. Applications].

The gynaecological laparoscopy is basical for the correct diagnosis of the ovaries and the uterus in sheep. Physiological (follicles, corpora lutea) and pathological findings (follicle cysts) are described and illustrated. Further, application techniques of the laparoscopic intrauterine insemination as well as of the embryo recovery and embryo transfer in embryo transfer programs are explained.

Animals↗