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Biomedical subjects

M Wolf

Publications and source records attributed to M Wolf.

At least 163 records · Page 9Linked to original sources
PubMed1999

Regional differences of cerebral hemoglobin concentration in preterm infants measured by near infrared spectrophotometry.

Near infrared spectrophotometry has been used to measure total cerebral hemoglobin concentration (micromol/l) as a major indicator of the oxygen transport capacity in neonates. The aim of this study was to find out how the position of the probe influences the quality of the measurement and the actual cerebral hemoglobin concentration-values. We studied 10 healthy preterm infants with a mean gestational age of 31.5 weeks and a birthweight of 1513 g. The data were collected by a two channel near infrared spectrophotometry system using a geometrical principle to measure absolute cerebral hemoglobin concentration. The incoming signal of the light emitting diode as a value allows a prediction of the quality of the measurement: a high value refers to a high signal/noise ratio. Starting from the centre of the forehead (0%) for each measurement the probe was moved by 2.5% of the headcircumference to the left respectively right side of the head up to 20%. The cerebral hemoglobin concentration-values increased from 87 respectively 93 micromol/l up to 164 respectively 173 micromol/l on the right respectively left side, while the light emitting diode signal-values decreased from 21 respectively 21 down to 10 respectively 11, the more laterally the probe was moved. There were two plateaus of these variables in the frontal (0-5%) respectively lateral (15-20%) region. A further investigation on a solid phantom for premature heads showed that hair has either no or a contrary effect on the cerebral hemoglobin concentration-values than expected. The extracerebral tissue (soft tissue, skull, cerebrospinal fluid layer) is discussed to have a significant influence on the light attenuation in adult heads. Still there is no evidence for a significant effect on prematures, because this overlying tissue is much thinner and more translucent than the one in adults. Absolute cerebral hemoglobin concentration measured by near infrared spectrophotometry is substantially influenced by the position of the probe at the infant's head. Considering our results we recommend placing the probe at 2.5% of the headcircumference away from the centre of the forehead for the measurement of cerebral hemoglobin concentration in premature infants.

Brain↗
PubMed1999

Cisplatin, methotrexate and bleomycin for the treatment of carcinoma of the penis: a Southwest Oncology Group study.

PURPOSE: We ascertained whether combined cisplatin, methotrexate and bleomycin have efficacy for treating locally advanced or metastatic carcinoma of the penis, and evaluate the toxicity resulting from this regimen. MATERIALS AND METHODS: Patients had biopsy proved locally advanced or metastatic epidermoid carcinoma of the penis. Chemotherapy consisted of 75 mg./m.2 cisplatin infused intravenously on day 1, 25 mg./m.2 intravenous bolus of methotrexate on days 1 and 8, and 10 unit per m.2 intravenous bolus of bleomycin on days 1 and 8 with a cycle length of 21 days. Our study was performed as a standard phase II evaluation with 2 stages of accrual. RESULTS: Enrolled in this study were 45 patients, including 40 who were evaluable for a response. There were 5 complete and 8 partial responses for a 32.5% response rate. Five treatment related deaths occurred and 6 of the 36 remaining patients evaluable for toxicity had 1 or more life threatening toxic episodes. CONCLUSIONS: A regimen of cisplatin, methotrexate and bleomycin appears to have promising results. However, toxicity was prodigious, and an emphasis of future research should be to decrease toxicity.

Adult↗
PubMed1999

[In Process Citation]

OBJECTIVE: The objective of the study was to analyse the prognostic impact of several criteria for median survival and recurrence free interval in patients with uterine sarcomas. Factors included to our analysis were the staging according to FIGO, DNA content (ploidy), mitotic index, histology, the kind of primary therapy, grading and menopausal status. MATERIAL AND METHODS: Retrospectively, clinical data of 78 patients (41 leimyosarcomas, 23 carcinosarcomas = homologous malignant mixed Mullerian tumors, 14 endometrial stromal sarcomas--10 low grade, 4 high grade) were analysed. Additionally, in 36 of the cases mitoses were counted. Furthermore, DNA ploidy was determined using image cytometry on paraffine sections stained according to the Feulgen method. Receptor status was determined using immunohistochemical staining. Two and five year survival rates were 22% and 15%. There were 21 cases with local relapse and 27 cases with metastasis. RESULTS: The staging according to FIGO was the main prognostic factor, significantly influencing median survival time (p = 0.001) as well as the recurrence free interval (p = 0.03). There was a significant difference between median survival time compared to mitotic index (p = 0.014) and DNA ploidy (p = 0.02). A mitotic index < 10/10 HPF and diploidy were related with a better prognosis. Receptor status did not have an impact on median survival time. CONCLUSIONS: As our results suggest, DNA ploidy and mitotic index are likely to provide additional information for prognosis in patients with uterine sarcomas and could be used as criteria for selecting patients for adjuvant therapy.

Journal Article↗
PubMed1999

[The new law concerning public health services in North Rhine- Westphalia--essentials and perspectives in dentistry].

A new regulation affecting the public health services (OGDG) in North Rhine Westphalia has been in effect since 1st January 1998. The present authors--members of a ministerial workgroup responsible for guidelines and recommendations for the implementation of the new regulation--have made an attempt to formulate the substantial and formal essentials of section 13 ODGD (dental health in children and the young) and its future perspectives in light of the reorientation of the national health service and, in particular, of dental services.

Germany↗
PubMed1998

[Physician-patient relations: right or self determination. Path across the Atlantic regarding medical responsibility].

In France, patients have a fundamental right to health care, specifically declared in the Public Health Code. Licensed physicians are endowed by law with the mission of providing such care. The patient-physician relationship thus operates in an atmosphere of mutual trust. This situation, derived from roman law, is much different from that in countries where Habeas Corpus is the founding principle. In the United States for example, in virtue of the right to autonomy or self-determination, a patient has to decide to receive health care. In both situations, patient consent is mandatory, but in France consent is a condition, and not the fundamental principle of health care. A recent court decision (Cour de Cassation, February 25, 1997) has however had considerable impact on the health care climate in France. According to this decision, the physician is charged with the responsibility of informing the patient of all possible risks inherent in a proposed treatment. In addition, the physician must be able to prove the patient has received such information. The danger is that health care in France depart from the notion of a medical mission, moving onto the unstable grounds of an open marketplace. If the physician becomes a salesperson meeting the desires of a client-patient, what will happen to the climate of mutual patient-physician trust so strong in France? There is an urgent need to preserve the fundamental right to medical care in France, a mission performed by legally designated physicians and other health carers, for the benefit of consenting patients.

Cross-Cultural Comparison↗
PubMed1998

Design and analysis for survival data under order restrictions with a modified logrank test.

We previously proposed a class of ordered weighted logrank tests for analysing censored survival data under order restrictions. However, the power of these tests is asymmetrical with respect to possible alternative configurations. While it is superior in most cases, the power can be inferior to the non-ordered logrank test in extreme cases. We propose a modified ordered logrank test which performs uniformly better than the non-ordered test. The power of the modified test is equivalent to the generalized Jonckheere's test but its computation is much simpler. We give sample size requirements for sufficient power to reject the global null hypothesis at specified hazard ratios between the control group and the best group. Following Fisher's least significant difference (LSD) strategy for multiple comparisons, power investigations indicate that the nominal power for the global test carries over to the control versus best comparison during pairwise testing. The power for detecting intermediate survival differences is inadequate but the sample sizes required to detect such differences may be impractical in most applications.

Clinical Trials as Topic↗
PubMed1998

Further observations of true mosaic trisomy 17 ascertained in amniotic fluid cell cultures.

Three new cases of true mosaic trisomy 17 (MT17) were diagnosed in amniotic fluid cells. Postnatal chromosome analysis from lymphocytes did not confirm the trisomic cell line, and follow-up studies showed normal psycho-motor development of the children, in one case up to the age of 4 1/2 years. We suggest that there are similarities between MT17 and MT20, in which the majority of pregnancies result in deliveries of healthy babies.

Adult↗
PubMed1998

A novel splice site mutation of the EXT2 gene in a Finnish hereditary multiple exostoses family. Mutations in brief no. 197. Online.

Hereditary multiple exostoses is a dominantly inherited disease characterized by multiple benign osteochondromas. The affected individuals have an increased risk of developing sarcoma. A large Finnish family with hereditary multiple exostosis was analyzed to find the disease-causing mutation. Blood samples were obtained from 35 family members, including 21 affected and 14 unaffected individuals. Using 2-point linkage analysis the EXT phenotype was shown to be linked to the recently cloned EXT2 gene on chromosome 11p11. The coding region of the gene was sequenced and a previously unreported splice site mutation found. This G to T transversion within a 5-prime splice donor site following exon 6 was shown to cause aberrant splicing of RNA. The described change is considered to be a novel disease-causing mutation in the EXT2 gene.

Alternative Splicing↗
PubMed1998

Granulocyte chemotactic protein 2 acts via both IL-8 receptors, CXCR1 and CXCR2.

Interleukin-8 (IL-8) acts on human neutrophils via two receptors, CXCR1 and CXCR2. It shares CXCR2 with all neutrophil-activating chemokines, which like IL-8 have a conserved Glu-Leu-Arg (ELR) N-terminal motif, but is generally considered to be the only relevant agonist for CXCR1. IL-8 has a basic residue at the sixth position after the second cysteine, which was suggested to contribute to CXCR1 specificity. Among the other ELR chemokines, only granulocyte chemotactic protein 2 (GCP-2) has such a basic determinant. Using Jurkat cells that stably express either CXCR1 or CXCR2, we studied receptor activation by IL-8, GCP-2 epithelial neutrophil-activating protein 2 (ENA-78) (which shares 77% identical amino acids with GCP-2) and growth-regulated oncogene alpha (GRO alpha). At 10 nM and higher concentrations, GCP-2 and IL-8 induced significant activation of CXCR1-expressing cells, but no activity was found with GRO alpha and ENA-78. As expected, however, all four chemokines had similar activities on CXCR2-expressing cells. A variant of GCP-2 in which the basic residue, Arg20, was replaced by a glycine was synthesized. This derivative was ineffective on CXCR1, but was as active as wild-type GCP-2 in CXCR2-expressing cells. GCP-2 displaced radiolabeled IL-8 from both receptors with low affinity, and in this respect resembled ENA-78 and GRO alpha. Our data show that GCP-2 acts via both IL-8 receptors and thus appears to be functionally more similar to IL-8 than to the other ELR chemokines. Activation of CXCR1 appears to depend significantly on the presence of a basic binding determinant close to the second cysteine.

Amino Acid Sequence↗
PubMed1998

Comparison of absolute cerebral haemoglobin concentration in neonates measured directly and by the oxygen swing method both based on near infrared spectrophotometry.

The total cerebral haemoglobin concentration (tHb in mumol/l) as a major indicator of the oxygen transport capacity is investigated in neonates. Two methods to determine tHb by near infrared spectrophotometry (NIRS) have evolved so far: The first method requires a slow oxygenation change with reference to arterial oxygen saturation (tHbo-method). The second method is based on a geometrical principle and a two channel NIRS instrument (tHbg-method). The aim of this study was to compare both methods quantitatively. 15 clinically stable preterm infants needing supplemental oxygen were included in this study. For each method the measurements of three infants were excluded due to unsatisfactory measurement quality. The remaining 9 neonates had a mean gestational age of 29 (range 25.1 to 31.4) weeks, birthweight of 1272 (740 to 1690) g and a postnatal age of 2.6 (0.5 to 5) days. In each infant 6 tHbo measurements were carried out. During each tHbo measurement the mean of the continuously available tHbg (Cerebral Redox Monitor 2020, Johnson & Johnson Medical) was calculated. The mean of all successful tHbo and corresponding tHbg was determined for each infant. The mean tHbg was 151 mumol/l (range 62 to 223 mumol/l) and the mean tHbo was 59 mumol/l (27 to 113 mumol/l). The regression line between the two methods was tHbg = 1.34 x tHbo + 72 mumol/l. The r was 83.6%. The correlation suggests, that both methods can be applied to measure tHb. However, it has to be taken into account that the tHbg-method returns significantly higher values than the tHbo-method.

Birth Weight↗
PubMed1998

[Molecular genetic study of the PAX6 gene in aniridia patients].

INTRODUCTION: Aniridia represents a congenital ocular disorder with partial or complete iris hypoplasia. The disorder is associated with poor vision, glaucoma, corneal and lenticular opacities, ectopia lentis due to abnormal zonula fibers, as well as optic nerve and macular abnormalities. Aniridia may present as either hereditary or sporadic cases. Some of the sporadic cases develop Wilms' tumor, frequently as part of the WAGR syndrome (Wilms' tumor, aniridia, genitourinary abnormalities and mental retardation). PAX6, a candidate gene located on chromosome 11p13, is often mutated in aniridia patients. The gene encodes a transcription regulatory protein. METHOD: Analysis of the PAX6 gene was done using PCR (polymerase chain reaction), SSCP (single strand conformation polymorphism) and DNA sequencing. RESULTS: In 13 of 20 aniridia patients a PAX6 gene mutation was found. CONCLUSION: The mutations result in a gene product with reduced function or a reduced PAX6 protein level. Molecular analysis of aniridia is also a valuable diagnostic tool for Wilms' tumor risk evaluation, as patients with proven PAX6 mutations--in contrast to cases with large deletions of the 11p13 region--are at no increased risk to develop Wilms' tumor.

Aniridia↗
PubMed1998

Laparoscopic vs open repair of gastric perforation and abdominal lavage of associated peritonitis in pigs.

BACKGROUND: Laparoscopy is increasingly used in conditions complicated by peritonitis, e.g., peptic ulcer perforation. Of some theoretical concern is the capnoperitoneum, which may aggravate peritonitis and induce septic shock due to increased intraabdominal pressure and distension of the peritoneum. This animal study was devised to analyze the effectiveness of laparoscopic versus traditional open repair of gastric perforation and abdominal lavage for associated peritonitis. METHODS: To simulate gastric perforation, female Duroc pigs were subjects to standardized gastrotomy. Either 6 or 12 h after gastric perforation, the animals underwent either traditional open or laparoscopic repair of the gastric defect and peritoneal lavage. The subjects were divided into the following four groups: peritonitis for 6 h and open surgery (group I) or laparoscopic surgery (group II); peritonitis for 12 h and open surgery (group III) or laparoscopic surgery (group IV). After an observation period of 6 days, the surviving animals were killed. The main outcome criteria were survival, perioperative changes of hemodynamics suggestive for septic shock, bacteremia, and endotoxemia. RESULTS: There were no significant differences between group I and II. Mortality was 22% in group III, as compared to 78% in group IV (p = 0.045). In group IV, the incidence of perioperative bacteremia and plasma endotoxin concentrations were significantly higher than in group III. Concomitantly, decreased mean arterial pressure and systemic vascular resistance, and increased cardiac output suggested a higher incidence of septic shock in group IV. CONCLUSION: Critical appraisal of laparoscopic surgery is warranted in conditions associated with severe, longstanding peritonitis.

Animals↗
PubMed1998

A clinical study of spider phobia: prediction of outcome after self-help and therapist-directed treatments.

The present clinical study was aimed at investigating predictors of treatment success, attrition and the extent of treatment needed to achieve clinically significant improvement in spider phobic patients. A total of 103 patients were included in the study after a detailed screening interview. There were four treatment conditions; self-help manual, video, group, and individual treatment, which the patients received in a hierarchical order providing they were not clinically significantly improved after the previous treatment. Pre and post each treatment the patients went through a behavioral approach test and filled in a number of self-report questionnaires. The results showed that 38 patients dropped out during the manual treatment, and 59 fulfilled the treatments to become clinically improved. The patients achieving clinical improvement after the two self-help treatments were significantly predicted, as was the extent of treatment needed. The significant predictors were credibility of the manual treatment and motivation for psychotherapy in general.

Adult↗