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Biomedical subjects

W Weber

Publications and source records attributed to W Weber.

At least 541 records · Page 30Linked to original sources
PubMedDate not supplied

Age-related variation in the DNA-repair synthesis after UV-C irradiation in unstimulated lymphocytes of healthy blood donors.

UV-C light-induced DNA-repair synthesis was studied in unstimulated lymphocytes of 51 healthy blood donors aged between 17 and 74 years. Repair synthesis was measured by the incorporation of [3H]thymidine after a 2-h incubation period in the presence of 2 mM hydroxyurea. The evaluation included (1) the spontaneous DNA-synthesis in unirradiated lymphocytes with and without hydroxyurea, (2) the DNA-repair synthesis in lymphocytes irradiated with UV-light. The interindividual variation was significantly higher than the methodological variation ascertained in 24 persons in whom 2 determinations were carried out. In blood donors aged between 17 and 39 years, the spontaneous DNA synthesis, both with and without hydroxyurea, was significantly lower than in older individuals. The DNA-repair synthesis was dependent on the dose of UV-C light between 2 and 16 J/m2. There were no significant differences in DNA-repair synthesis in the age range 17-74 years. The variations in rate of DNA-repair synthesis (greater or lesser degree of [3H]thymidine incorporation beyond the 99% confidence range) were wider in older (44-74 years), than in younger individuals.

Adolescent↗
PubMedDate not supplied

Para-[18F]fluorobenzylguanidine kinetics in a canine coronary artery occlusion model.

BACKGROUND: The kinetics of para-[18F]fluorobenzylguanidine ([18F]PFBG) were investigated in a canine coronary artery occlusion model. METHODS AND RESULTS: Five dogs were imaged by positron emission tomography (PET) before and after complete surgical ligation of the left anterior descending coronary artery. PET studies included a 10-minute dynamic [13N]NH3 perfusion scan, followed 1 hour later by 3-hour dynamic [18F]PFBG scanning. [18F]PFBG and [13N]NH3 images demonstrated homogeneous myocardial uptake/perfusion before infarction. One hundred eighty minutes after [18F]PFBG administration, myocardial accumulation was decreased by 60% (day 2, 0.0065% +/- 0.0015% injected dose/ml) and 58% (day 16, 0.0069% +/- 0.003% injected dose/ml) compared with a similar myocardial region of interest from the preinfarction (0.016% +/- 0.005% injected dose/ml) study. Myocardial accumulation of [13N]NH3 at 9 minutes showed a 52% (day 2) and 7% (day 16) decrease compared with the preinfarction study. The accumulation of [18F]PFBG in the infarction was decreased significantly at 120 and 180 minutes on all postinfarction studies (p = 0.01). In three dogs a significant decrease in the myocardial norepinephrine concentration was documented in the area of infarction (237 +/- 94 ng/gm) versus the noninfarcted (1018 +/- 48 ng/gm) myocardium (p = 0.001). CONCLUSIONS: A decreased accumulation of [18F]PFBG was observed in the area of myocardial infarct in this canine model. The magnitude of the decrease in [18F]PFBG was larger than that seen with [13N]NH3 on day 16 after infarction, suggesting reperfusion and persistent sympathetic neuronal dysfunction.

Animals↗
PubMedDate not supplied

[Striated muscle microvascular response to implants with sol-gel calcium phosphate coating. A comparative in vivo study].

AIM: Local microvascular perfusion plays an important role in reparative processes and the pathogenesis of infection. The impairment of skeletal muscle microcirculation by a biomaterial may therefore have profound consequences. The aim of our study was to determine whether the biological acceptance of the widely utilised implant material stainless steel can be improved by a coating of sol-gel calcium phosphate. METHODS: Using the hamster dorsal skinfold chamber preparation and intravital microscopy, we quantified nutritive perfusion and leukocyte-endothelium interaction in skeletal muscle after implantation of sol-gel calcium phosphate-coated stainless steel- and commercial pure titanium implants, and compared these results to those obtained with uncoated stainless steel and titanium. RESULTS: Within the first 24 h after implantation, animals with calcium phosphate coated stainless steel showed a significantly lower inflammatory response than did those with an uncoated stainless steel implant. After 24 h the quantified microcirculatory parameters deteriorated for animals with a calcium phosphate-coated stainless steel plate, indicating that, for as yet unknown reasons, the shielding mechanism of the calcium phosphate seems to deteriorate. Although not as inert as pure titanium, we found a relatively low inflammatory response for calcium phosphate coated titanium over the whole observation period, suggesting that the coating as such is well tolerated by the skeletal muscle microcirculation. CONCLUSIONS: Our in vivo results suggest that the biological acceptance of a conventional stainless steel implant can be improved over a short term by a sol-gel coating of calcium phosphate. Concerning tolerance by the local vascular system, commercially pure titanium currently remains unsurpassed.

Animals↗
PubMedDate not supplied

Absence of Yq microdeletions in infertile men.

Microdeletions of the long arm of the Y chromosome (Yq) were described in men with idiopathic azoo- or oligozoospermia and seem to cause impairment of spermatogenesis. Deletion frequencies differ considerably among selected infertile men. The aim of this study was to investigate the prevalence of Yq microdeletions in patients with idiopathic infertility. Men with azoospermia or oligozoospermia resulting from endocrine or obstructive causes or with a constitutional cytogenetic anomaly were excluded. Ninety-seven patients presenting at infertility centers in Leipzig and Zurich were included in the study. Sixty-four (66%) of them were severely oligozoospermic (sperm concentrations < 5 x 10(6)/mL) and 33 (36%) were azoospermic. A sequence-tagged site (STS) PCR strategy was applied for the microdeletion screening. Thirteen STS markers spanning the whole euchromatic region of Yq were used. No Y-chromosomal microdeletion could be detected in these 97 infertile men. This result suggests a much lower Yq deletion frequency than previously thought, even among strictly selected patients with idiopathic azoo- or oligozoospermia.

Adolescent↗
PubMedDate not supplied

Apolipoprotein E-binding proteins isolated from dog and human liver.

Chylomicron remnant catabolism appears to be mediated by apolipoprotein (apo) E binding to hepatic lipoprotein receptors. Previously, the apo B,E(LDL) receptor and a unique apo E-binding protein (referred to as the apo E receptor) were isolated from solubilized canine and human livers. In the present study, the apo E-binding fraction was further characterized and found to contain at least three proteins, all of which bind apo E-containing lipoproteins with high affinity. The 56-kDa band was found to contain the alpha- and beta-subunits of F1-ATPase, presumably derived from mitochondrial membranes. In addition, an apo E-binding protein with an apparent Mr approximately equal to 59,000 was identified. The 59-kDa protein displays calcium-independent binding on ligand blots, but displays both calcium-dependent and -independent binding in assays performed with detergent-solubilized protein. The 59-kDa protein recognized lipid-free as well as lipid-bound apo E in ligand blots, and also bound apo E-2, apo E-3, and apo E-4 in a comparable way. Monoclonal antibodies produced against the 59-kDa protein did not react with the 56-kDa proteins. Normal human liver, as well as the liver of a patient lacking the apo B,E(LDL) receptor, possessed the 56-kDa and 59-kDa proteins. These data indicate that liver cells possess at least three proteins, in addition to the apo B,E(LDL) receptor, that bind apo E-containing lipoproteins with high affinity. The physiological role of these proteins in apo E metabolism remains to be determined.

Animals↗
PubMedDate not supplied

A nonspecific, single-stranded nuclease activity with characteristics of a topoisomerase found in a major grass pollen allergen: possible biological significance.

The major allergen from timothy grass pollen, Phlp5b (Phleum pratense), was shown to exhibit ribonuclease activity. It turned out that the C-terminal portion of this molecule was the biologically active domain. Here evidence is presented that the allergen is a single-stranded, sugar-nonspecific nuclease with topoisomerase activity. An isomerase-specific active site was identified, and a non-active mutant was constructed by site directed mutagenesis, and showed no nucleolytic activity. In contrast to the wild type (WT), the mutant did not dimerize. Although the binding capacity of IgE antibodies toward the mutant was reduced as compared to the WT, the allergenic activity was retained. We conclude that the allergen Phlp5b is a single-stranded nuclease with an unusual topoisomerase-like activity. This biological activity is not by itself connected to the allergenicity of the molecule. Whether the enzymatic activity is responsible for the induction of the allergic sensitization and inflammation remains an open question.

Allergens↗
PubMedDate not supplied

In vitro fertilization: increased VLA (very late antigen) integrins and fibronectin after acrosome reaction.

The pattern of detectable adhesion molecules (AM) on human ejaculated spermatozoa used for in vitro fertilization (IVF) of human oocytes was evaluated. The percentage of spermatozoa with the alpha chains 3, 4, 5, and 6 of the integrins (also called very late antigens, VLA alpha 3, 4, 5, 6), the alpha V and the beta 3 chains, as well as the matrix proteins laminin and fibronectin, were determined by flow cytometry using monoclonal antibodies against integrins and matrix proteins before and after the acrosome reaction. This reaction was induced by the low-temperature method according to P. Sanchez, E. Töpfer-Petersen, R. J. Aitken, and W. B. Schill (1991, Andrologia 23:197-203) and monitored by the binding of FITC-conjugated Pisum sativum agglutinin. Twenty-three of 34 investigated semen samples fertilized at least one oocyte (fertile group) and 11 samples did not induce a pronucleus formation or cleavage of an oocyte (infertile group). Significant differences in the classical semen parameters between both semen sample groups could be shown only for the percentage of progressively motile spermatozoa (p = .046, U test). The spermatozoa of the fertile group showed a significantly higher expression of VLA alpha 3 (p = .045) and fibronectin (p = .048). Additionally, after the loss of the acrosome a significantly higher expression of alpha 4, alpha 5, and alpha 6 chains of integrins (p < .05) was detected in the fertile semen group. In contrast, the inducibility of the acrosome reaction differed only to a nonsignificant extent (p = .094). These data suggest that spermatozoa showing a higher expression of the alpha chains of the integrins after the acrosome reaction have a better fertilization rate in vitro.

Acrosome↗
PubMedDate not supplied

Profile of familial breast cancer in Alexandria, Egypt.

Nearly two thirds of the cancers which will appear in the next 25 years will occur due to unawareness of the public. In a population genetic study in Alexandria, Egypt, we found that the parents of 20% of the population are first degree cousins. Out of 9,587 female cancer cases registered in the last 10 years by the Alexandria Cancer Registry, 3250 (33%) were breast cancer. Twelve percent of breast cancer patients had a positive first-degree relative family history of cancer. Familial breast cancer (FBC) occurred at a younger age, ranging from 23-74 years, with a median equal to 46.5 years compared to 35-76 years, with a median of 54.5 years, in non-familial cases. The aim of this work was to show how familial cancer registries can produce useful data, helping to develop a data base of familial cancer, for the primary care program to control the morbidity of breast cancer in females by identification of those with a positive family history of cancer who are at a high risk of developing breast cancer.

Adult↗
PubMedDate not supplied

Familial cancer diagnosis.

Familial clustering of cancer is well known from epidemiologic studies. This can be due to chance, shared environmental influences, shared genes and chance-environmental-genetic interactions. Family studies are a key to the understanding of the environmental and genetic etiology of chronic disease. Cancer families are human models of susceptibility to neoplasia. More and more people are aware of, and anxious about, their cancer risk. High-risk individuals can benefit from prevention and early detection programs. In medical practice the patient workup should include a carefully obtained family history. This low technology method has the potential for reduction of cancer morbidity and mortality. Every person should create his/her own family tree and discuss it with his/her doctor. This is a step each individual can take for his/her health.

Family Health↗
PubMedDate not supplied

Relevant factors in the prognosis of ductal pancreatic carcinoma.

Because it is important to assess relevant prognostic factors when deciding which patients will profit from pancreatic resection and which will not, 484 patients with ductal pancreatic carcinoma who were operated on between 1 January 1978 and 31 December 1987 in the Department of General and Abdominal Surgery of Mainz Medical School were studied retrospectively. Prognostically favourable factors were: a history of 8 weeks or less, the presence of jaundice, the absence of back pain, a well to moderately differentiated carcinoma, a tumour less than 3 cm in diameter, a preoperative CA19-19 value of less than 400 U/ml, and no sign of lymph node metastases or other metastatic spread. Only 19 patients (3.9%) satisfied these criteria. Our objective is to now check these results in a prospective study with a larger number of patients and, in addition, to compare the quality of life of patients who were treated by resection with that of those who received palliative treatment.

Adolescent↗
PubMedDate not supplied

Outcome of acute vertebrobasilar occlusions treated with intra-arterial fibrinolysis in 180 patients.

BACKGROUND AND PURPOSE: To evaluate predictors of recanalization and a favorable neurologic outcome in patients with acute vertebrobasilar occlusion (VBO) treated with local intra-arterial fibrinolysis (LIF). METHODS: The multicentric data of 180 patients with acute VBO treated with LIF were retrospectively evaluated. The modified Rankin scale (mRS) was used to evaluate the neurologic status before LIF and at the time of discharge. Patient's sex, age, etiology of VBO, recanalization, symptom duration before LIF, and pretreatment mRS were correlated with posttreatment mRS. Multiple logistic regression analysis was used to identify independent variables for recanalization and neurologic outcome. RESULTS: The overall mortality was 43%. Complete recanalization was achieved in 99 (55%) patients and a partial recanalization in 35 (19%) patients, respectively. Recanalization was significantly associated with a favorable outcome (P < .001). The success of recanalization was negatively correlated with the volume of the thrombus (P < .001). No correlation was found between site and etiology of VBO and recanalization. Neurologic outcome correlated strongly with the pretreatment mRS (P < .001) and also with age (P < .02). Coma lasting less than 4.5 hours led to a positive trend toward a better outcome after univariate testing (P < .001). CONCLUSIONS: Success of recanalization and neurologic status before treatment predict neurologic outcome in patients with VBO. Thrombus volume has an adverse effect on the recanalization success.

Acute Disease↗
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[Late sequelae of childhood condylar process fractures and their therapeutic options].

The causes of TMJ ankylosis after collum mandibulae fractures in the early childhood are discussed and two different surgical treatment approaches are presented. In cases of unilateral involvement it often suffices to separate the ankylosed area while the rest of the joint is spared; where as in cases of pronounced bilateral ankyloses wide reactions with temporary implantation of bone cement are carried out.

Adult↗
PubMedDate not supplied

Hematological toxicity of adjuvant portal liver infusion with fluorouracil, mitomycin and heparin.

Adjuvant perioperative liver infusion chemotherapy with fluorouracil, mitomycin and heparin caused mild but significant myelosuppression in the first two postoperative weeks. This was associated with a slightly increased bleeding tendency. Mortality was not increased. Future trials might combine chemotherapy with hematopoietic growth factors in order to minimize myelosuppression.

Antineoplastic Agents↗
PubMedDate not supplied

[Results after treatment of facial fractures with the Wurzburg titanium miniplate system].

The basic principles of anatomy and materials science, forming the foundation for the application of the Würzburg titanium miniplate system, are described in detail. Based on 252 midfacial fractures and 315 mandibular fractures treated with this Miniplate system between 1984 and 1987, the clinical results of using this system in traumatology are discussed.

Bone Plates↗
PubMedDate not supplied

Manifestations of hereditary colorectal cancer.

Seven families with hereditary colorectal cancer syndromes are presented. Four are of the nonpolyposis type, two with polyposis, and one with a mixed pattern. We have observed an early onset of hereditary colorectal cancer, the nonpolyposis type of which manifests itself mostly in the proximal colon, whereas the syndrome with polyposis manifests itself in the distal colon. In addition, the rest of the gastrointestinal tract may be involved. Therefore surveillance endoscopies in affected families should be started at least 20 years earlier than usual.

Adenomatous Polyposis Coli↗
PubMedDate not supplied

[Treatment of midfacial fractures with bicoronal incisions].

During the period 1985 to 1987 twelve patients with central or centrolateral midfacial fractures were operated via a bicoronal approach at the university hospital for oro- and maxillofacial surgery in Wurzburg. All fractures were treated with the Wurzburg titanium mini-plates. Esthetic and functional results were very satisfactory, since this type of incision offers good access to the site of surgery without causing surgery induced scars in the visible area.

Adult↗