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Biomedical subjects

M Wolf

Publications and source records attributed to M Wolf.

At least 217 records · Page 12Linked to original sources
PubMed1997

Anatomy of the postauricular island "revolving door" flap ("flip-flop" flap).

Reconstruction following resection of auricular (cavum conchae) lesions may be done with a retroauricular rotation flap. Recently there has been revived interest in this elegant reconstructive procedure. Although the vascular anatomy of the area was studied, no direct study of flap anatomy was reported. Six fresh adult male cadaveric dissections of the retroauricular area were performed. The skin and underlying subcutaneous tissue layer were reflected to correspond with flap size, and anatomic structures were studied. Dissection was carried out on 12 ears. The origin of the occipital belly of the occipitofrontalis muscle arising from the posterior mastoid region was identified in four patients and only as part of the fascial layer overlying the posterior mastoid region. Only a small portion of the sternocleidomastoid tendon at best is possibly incorporated in the flap. It seems that only a negligible contribution to the flap is derived from the temporalis muscle. The posterior auricular muscle was identified in all patients and its origin from the skull was (in all patients) included or bordered the posterior flap region. The posterior auricular artery (PAA) was seen in all 12 dissections. The artery was adjacent to the styloid process medial to the parotid gland superficially between the auricular cartilage and the mastoid process. The PAA was then found on the periosteum of the mastoid process, ascending deep to the posterior auricular muscle. The flap seems to be a truly fasciocutaneous flap with small, questionable, superior and anteroinferior muscular contributions, and an inclusion of the rather small posterior auricular muscle. As reported in other studies, blood supply to the area seems to be derived from the PAA.

Adult↗
PubMed1997

Absence of cross-reactivity of SR90107A/ORG31540 pentasaccharide with antibodies to heparin-PF4 complexes developed in heparin-induced thrombocytopenia.

New carbohydrate-based anticoagulants devoid of the side effects of unfractionated heparin are currently under development and show a major potential for patients with heparin-induced thrombocytopenia (HIT) who still require efficient antithrombotic therapy. As HIT is usually associated with antibodies to heparin-platelet factor 4 (H-PF4) complexes, cross-reactivity of the heparin pentasaccharide SR90107A/ORG31540 was tested in the presence of PF4 with the plasma from 49 patients with HIT. No cross-reactivity was observed whatever the pentasaccharide concentrations. Although more extensive studies are required for excluding its total absence of immunogenicity and pathogenicity, this pentasaccharide is a candidate for use in emergency situations in patients with HIT.

Autoantibodies↗
PubMed1997

Continuous noninvasive measurement of cerebral arterial and venous oxygen saturation at the bedside in mechanically ventilated neonates.

OBJECTIVES: To test the practicablity of a new spectrophotometric method using pulse oximetric techniques in combination with special filters for the noninvasive determination of cerebral arterial and venous oxygen saturation and oxygen extraction in neonatal intensive care unit patients. The spectrophotometer used three different wavelengths at a sampling rate of 100 Hz. DESIGN: Clinical evaluation of a new method and comparison with previously published data. SETTING: Design and construction of the special spectrophotometer at the Biomedical Engineering Laboratory of the Swiss Federal Institute of Technology. Measurements in the neonatal intensive care unit of the University Hospital, Zurich, Switzerland. PATIENTS: Convenience sample of 15 clinically stable newborn infants, who were mechanically ventilated and receiving supplemental oxygen. Median gestational age was 29 5/7 wks (range 26 3/ 7 to 36 0/7), median birth weight was 1555 g (720 to 2500), median postnatal age was 4 days (1 to 10). INTERVENTIONS: The emitter and receiver were placed on the forehead near the sagittal sinus, between 2 and 2.8 cm apart, and the pulsating light attenuations (arterial and venous pulse waves) were recorded. MEASUREMENTS AND MAIN RESULTS: Arterial and venous pulse waves were satisfactory in 10 of 15 infants. Mean cerebral arterial oxygen saturation was 89.9 +/- 5.4% (SD), mean cerebral venous oxygen saturation was 73.0 +/- 8.9%, and mean cerebral oxygen extraction was 16.9 +/- 11.7%. A linear regression analysis demonstrated a significant correlation between mean PCO2 and venous oxygen saturation (slope 1.0%/torr, p < .05) and between mean PCO2 and cerebral oxygen extraction (slope -1.3%/torr, p < .05). CONCLUSION: This new method has the potential for monitoring continuously, noninvasively, and simultaneously cerebral arterial and venous oxygen saturation and oxygen extraction in mechanically ventilated preterm infants.

Blood Gas Analysis↗
PubMed1997

Benign osteonecrosis of the external ear canal.

Benign osteonecrosis (BON) of the external ear canal (EEC), also termed as focal or circumscribed necrotizing lesion, is an infrequent phenomenon with distinctive features and of an obscure origin. Five patients with BON of the EEC presented with aggressiveness and extension of varying degree including involvement of the middle ear. It seems that the disease might have a self limited course (two patients) though, at times, extensive measures including hyperbarric oxygen therapy (one patient) should be applied.

Adult↗
PubMed1997

Distribution of colonization factor antigens among enterotoxigenic Escherichia coli strains isolated from patients with diarrhea in Nepal, Indonesia, Peru, and Thailand.

Samples (1,318) of enterotoxigenic Escherichia coli (ETEC) isolated in 1994-1995 from children with diarrhea from Nepal, Indonesia, Peru, and Thailand were examined for colonization factor antigen (CFA) and coli surface (CS) antigens. Fifty-five percent of 361 heat-labile and heat-stable (LT-ST), 14% of 620 LT-only, and 48% of 337 ST-only ETEC had CFA/CS antigens. LT-ST ETEC strains were predominantly in the CFA II group, and ST only strains were in the CFA IV group. Additional studies are needed to identify ETEC strains that do not have CFA/CS antigens.

Adult↗
PubMed1997

Coli surface antigens associated with enterotoxigenic Escherichia coli strains isolated from persons with traveler's diarrhea in Asia.

Enterotoxigenic Escherichia coli (ETEC) strains were isolated from travelers or military personnel who developed diarrhea after visiting Nepal or who were deployed to Thailand, Indonesia, or the Philippines. ETEC isolates were examined for colonization factor antigen (CFA). CFAs were identified on 59% (40 of 68) of the isolates examined. The lack of a detectable CFA on 41% (28 of 68) of the isolates is of concern for the development of an effective ETEC vaccine.

Antigens, Bacterial↗
PubMed1997

Effect of nursing in the head elevated tilt position (15 degrees) on the incidence of bradycardic and hypoxemic episodes in preterm infants.

OBJECTIVE: We investigated whether nursing in the head elevated tilt position (HETP), compared with the horizontal position, has any effect on the incidence of bradycardic and hypoxemic episodes in preterm infants. METHODS: Twelve spontaneously breathing preterm infants with idiopathic recurrent apnea were studied in a randomized controlled crossover trial. Nine infants were treated with aminophylline. Each spent a total of 24 hours in the horizontal prone position and a total of 24 hours in HETP (prone, 15 degrees). The position was changed in random order every 6 hours. Thoracic impedance, heart rate, and arterial oxygen saturation were recorded continuously. The frequency of isolated hypoxemia (arterial saturation <80%), of isolated bradycardia (heart rate <90 beats per minute), and of mixed events was analyzed and compared without knowledge of the allocated position. RESULTS: In total, there were significantly fewer bradycardic and/or hypoxemic episodes (28.2%) in HETP compared with the horizontal position (mean difference, 13.35 episodes/24 hours; 95% confidence interval [CI]: 5.9- 20.8). The decrease was largest for isolated hypoxemic episodes (48.5%; mean difference, 11.74 episodes/24 hours; 95% CI: 6.1-17.4). Isolated bradycardic episodes (mean difference, 2.27 episodes/24 hours; 95% CI: -0.78-5.31) and mixed events were not decreased significantly in HETP. CONCLUSIONS: Nursing in a moderately tilted position (15 degrees) reduces hypoxemic events in preterm infants. This intervention is easy to apply, quickly reversible, and can be combined with drugs such as aminophylline.

Apnea↗
PubMed1997

Prognostic value of cytogenetic abnormalities in previously untreated patients with non-Hodgkin's lymphoma.

In this study cytogenetic findings have been correlated with prognosis in 78 previously untreated patients with non-Hodgkin's lymphoma (NHL) presenting between 1983 and 1988. The median follow-up was 7 years (range 2-9 years). There was no significant difference in the duration of survival of 33 patients with only abnormal karyotypes, 35 patients with a mixture of normal and abnormal karyotypes (AN) and 10 patients with only normal karyotypes (NN). This was true for the entire group (p = 0.6) as well as for the subsets of diffuse lymphomas (DL) and follicular lymphomas (FL) (p = 0.6 and 0.4, respectively). Monosomy 14 was the only abnormality in the entire group of patients to be associated with a statistically significant difference in survival duration (p = 0.046). Among the FL patients, trisomy 7 (p = 0.046) and trisomy 12 (p = 0.010) were associated with shorter survival. Presence of t(14;18) did not influence survival in the entire group (p = 0.16), nor in any of the histological subgroups. Among the FL patients with t(14;18), presence of additional cytogenetic abnormalities was not associated with a worse outcome. The lack of consistency of results between various studies is likely to be due to several factors and the prognostic significance of karyotypic abnormalities can only be clarified by large prospective studies employing uniform treatment policies.

Adolescent↗
PubMed1997

Clinical features in 36 patients homozygous for the ARG 506-->GLN factor V mutation.

We analyzed the clinical features of 36 patients homozygous for the Arg 506 to Gln factor V mutation and found a circumstantial event at risk for thrombosis in 29 of the 31 patients with thrombosis. The most frequent predisposing factors were the post-partum period and the use of oral contraceptives in women, and surgery in both sexes. Venous thrombosis recurred in 48% of the patients. One patient had a myocardial infarction at age 33 years, and also had an antiphospholipid syndrome. Homozygous Gln 506 mutation leads to far less severe thrombotic complications than homozygous protein C and protein S deficiencies and does not seem to predispose patients to arterial thrombosis.

Adult↗
PubMed1997

["Second opinion" in online radiology via Internet: report on implementation and analysis of reliability of findings in sectional images].

Numerous medical on-line services have already been established in the world-wide internet. In connection with the Information service TELESCAN, sponsored by the EU, a pilot project has been initiated which offers a radiological "second opinion" via the transmission of radiological findings and images that have been previously rendered anonymous. In addition to a description of the basic implementation, tests of the diagnostic certainty of the transmitted cranial computed tomographs have been performed. The CT images were digitized with a document camera, transmitted over the Internet, and then evaluated on the receiver's monitor. Both the transfer of originally generated digital image files (in ACR-NEMA or DICOM) as well as graphic files after digitization of X-ray films, for example by a document camera, is possible via electronic post (e-mail). Visualization by the receiver requires the use of current proprietary software for special medical image formats, while standard graphic formats such as GIFF or JPEG can be visualized with the usual Internet software. In an ROC analysis, 56 individual images of cranial computed tomographs, half with pathological findings such as space-occupying lesions, infarcts, or brain edema, were tested with regard to the diagnostic certainty after digitization and transmission. In comparison with the original film findings, there was a slight but statistically not significant reduction in diagnostic certainty of the images evaluated on screen after transfer via the Internet. We believe that this result is due to the low local resolution, low dynamic range, the high image noise and of CT arising from the window technique. The same parameters are probably valid for MRI. The result cannot be applied to conventional radiography including mammography because, in comparison to the mentioned image techniques, their local resolution is high and image noise is considerably lower.

Computer Communication Networks↗
PubMed1997

Long-term survival advantage of MACOP-B over CHOP in intermediate-grade non-Hodgkin's lymphoma. The Australian and New Zealand Lymphoma Group.

BACKGROUND: The initial publication of the results of the Australian and New Zealand Lymphoma Group (ANZLG) randomized controlled trial comparing MACOP-B and CHOP in patients with intermediate-grade non-Hodgkin's lymphoma (NHL) showed equivalent complete response rates, time to treatment failure, and survival. Here we report the long-term follow-up of the 236 patients entered on that study to determine if there were any long-term advantages or disadvantages associated with MACOP-B. PATIENTS AND METHODS: Two hundred thirty-six eligible patients were randomized between October 1986 and June 1991. The median duration of follow-up has been extended from 3.2 years in our previous publication to 6.5 years. RESULTS: As previously reported, the complete response (CR) rate for MACOP-B and CHOP chemotherapy was 51% and 59%, respectively. The estimated failure-free survival rate for MACOP-B and CHOP patients was 42% and 30%, respectively, at 5 years (P = 0.045) and 37% and 25%, respectively, at 8 year (P = 0.057). The estimated overall survival rate at 5 years was 54% for MACOP-B and 41% for CHOP patients (P = 0.035) and at 8 years was 45% and 36%, respectively (P = 0.16). CONCLUSION: With this extended follow-up, we have shown a long-term survival advantage for MACOP-B chemotherapy over standard CHOP in patients with intermediate-grade non-Hodgkin's lymphoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

[Informed consent: what is the question? Correlation between practice and theory].

Informed consent in medical or human experimentation is a concept generally accepted by most doctors. The foundation of informed consent is self-determination and, in the legal setting of France, contractual agreement. The practical application of informed consent in medical specialities such as psychiatrics or intensive care raises difficult problems subject to much debate. Contemporary history would suggest that the strength of informed consent may be highly insufficient to avoid the risk of dictated power dominating-patients. In order to find a solution to these problems, the field of action of informed consent must be widened. We propose here to define informed consent as one of many means to defend patient dignity and human rights.

Emergency Medicine↗
PubMed1996

Two distinct stimulus-dependent pathways lead to production of soluble murine interleukin-4 receptor.

The IL-4R exists in two forms, either membrane bound or as a soluble (s) molecule. Since the sIL-4R binds to its ligand with high affinity, thereby acting as an immunoregulatory molecule, we were interested in the processes leading to its release. First, the release of sIL-4R in the model of murine leishmaniosis was analyzed. Infection of mice with Leishmania major resulted in up-regulation of sIL-4R production by Ag-stimulated CD4+ T cells, with a maximum around 7 days after infection. To clarify the mechanisms underlying sIL-4R release, in vitro studies were performed. After stimulation of naive lymphoid cells with IL-4, sIL-4R release was dependent on up-regulation of spliced IL-4R mRNA, as shown by inhibition with specific antisense oligonucleotides. In contrast to this, no increase in the spliced IL-4R mRNA and no inhibitory influence of antisense oligonucleotides were observed after stimulation of T cells from IL-4-deficient mice with anti-CD3 mAb. Thus, TCR stimulation can lead to IL-4-independent sIL-4R production. Under these conditions proteolytic shedding of membrane-bound IL-4R appears to be the principal mechanism of release, since in contrast to stimulation with IL-4, iodinated sIL-4R could only be immunoprecipitated after cell surface labeling and subsequent TCR stimulation. The common gamma-chain, a component of the IL-4R complex, did not appear to be involved in the pathways leading to sIL-4R expression. This analysis suggests the existence of two differentially regulated pathways of sIL-4R release, possibly having different consequences for the regulation of IL-4 bioactivity.

Alternative Splicing↗
PubMed1996

Presence of autoantibodies to interleukin-8 or neutrophil-activating peptide-2 in patients with heparin-associated thrombocytopenia.

Eighty-seven patients with heparin-associated thrombocytopenia (HAT) showed either a positive heparin platelet aggregometry test result and/or the presence of antibodies to heparin-platelet factor 4 (H-PF4) complexes by enzyme-linked immunosorbent assay (ELISA). Fifteen of these patients lacked antibodies to H-PF4, and plasma from these patients was analyzed for the presence of antibodies to PF4-related chemokines, Neutrophil-activating peptide-2 (NAP-2) and interleukin-8 (IL-8). Of these 15 patients, 6 showed antibodies to IL-8 and 3 to the platelet basic protein (PBP)-derived protein, NAP-2. Antibodies to IL-8 and NAP-2 were not observed in control patients (n = 38), patients with HAT and H-PF4 autoantibodies (n = 72), patients with autoimmune diseases (n = 21), or patients with non-HAT thrombocytopenia (n = 30). Five of these nine patients with anti-IL-8 or anti-NAP-2 developed thrombosis during heparin treatment, which is not statistically different from the patients with H-PF4 antibodies. The existence of autoantibodies to IL-8 and NAP-2 in HAT patients highlights the significance of chemokines in the pathogenesis of HAT. The contribution of heparin in vitro was minimal in patients with anti-IL-8 and anti-NAP-2 antibodies, suggesting a biologic difference from the majority of patients with HAT and anti-PF4 antibodies. It may be that antibodies to IL-8 and NAP-2 have weaker affinity for heparin and that the ELISA system may not reflect in vivo heparin-chemokine complex formation. Alternatively, antichemokine autoantibodies may predate heparin exposure, and the role of heparin in initiating HAT may be to mobilize the chemokines and to target them to platelets, neutrophils, or endothelial cells. Subsequent chemokine-binding autoantibodies then lead to cell activation resulting in thrombocytopenia and thrombosis.

Adult↗
PubMed1996

Different functions for the interleukin 8 receptors (IL-8R) of human neutrophil leukocytes: NADPH oxidase and phospholipase D are activated through IL-8R1 but not IL-8R2.

Two monoclonal antibodies, anti-IL8R1 and anti-IL8R2, raised against both interleukin 8 receptors (IL-8R) of human neutrophils, IL-8R1 and IL-8R2, were used to study individual receptor functions after stimulation with IL-8, GRO alpha, or NAP-2. Efficacy and selectivity of the antibodies were tested in Jurkat cells transfected with cDNA coding for one or the other receptor. The binding of 125 I labeled IL-8 and IL-8-induced changes of the cytosolic free Ca2+ concentration were inhibited by anti-IL8RI in cells expressing IL-8R1 and by anti-IL8R2 in cells expressing IL-8R2. In human neutrophils, release of elastase was observed after stimulation with IL-8 or GRO alpha. The response to IL-8 was inhibited slightly by anti-IL8R1 and more substantially when both monoclonal antibodies were present, while the response to GRO alpha was inhibited by anti-IL8R2 but was not affected by anti-IL8R1. These results indicate that both IL-8 receptors can signal independently for granule enzyme release. Superoxide production, a measure of the respiratory burst, was obtained with increasing concentrations of IL-8 with maximum effects at 25 to 50 nM, but no response was observed upon challenge with GRO alpha or NAP-2 up to 1000 nM. The superoxide production induced by IL-8 was inhibited by anti-IL8R1, but was not affected by anti-IL8R2. Stimulation of neutrophils with IL-8, in contrast to GRO alpha or NAP-2, also elicited phospholipase D activity. The effect of IL-8 was again inhibited by anti-IL-8R1 but not by anti-IL8R2, indicating that this response, like the respiratory burst, was mediated by IL-8R1. Taken together, our results show that IL-8R1 and IL-8R2 are functionally different. Responses, such as cytosolic free Ca2+ changes and the release of granule enzymes, are mediated through both receptors, whereas the respiratory burst and the activation of phospholipase D depend exclusively on stimulation through IL-8R1.

Antigens, CD↗