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Biomedical subjects

A Meyer

Publications and source records attributed to A Meyer.

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

Combined heterozygous deficiency of the classical complement pathway proteins C2 and C4.

Genetic deficiencies of components of the classical pathway of complement activation are associated with an increased risk for the development of autoimmune and immune complex-mediated diseases. In the present study we report on the molecular and clinical features associated with combined heterozygous C4 and C2 deficiency in 15 individuals investigated within six families. Approximately 30% of the individuals manifested SLE or another autoimmune condition. Heterozygous C2 deficiency was related to a 28-bp deletion in the C2 gene (C2 deficiency type I), in most cases within the HLA-A25 B18 C2Q0 BfS C4A4B2 DR2 haplotype. Among 13 partial C4-deficient haplotypes transmitted, 8 carried C4A*Q0 alleles and 5 C4B*Q0 alleles. In seven cases the C4A*Q0 alleles were associated with a deletion of the C4A/CYP21P genes within the HLA-B8 C2C BfS C4AQ0B1 DR3 haplotype. In three cases, the C4B*Q0 allele was associated with a deletion of the C4B/CYP21P genes within the HLA-B18 C2C BfF1 C4A3BQ0 DR3 haplotype. In the other cases, C4A*Q0 or C4B*Q0 was dependent on as yet uncharacterized defects in the C4 gene or in C4 gene expression. In view of the relatively high frequency of heterozygous C4 deficiency in the normal Caucasian population, the expected frequency of the combined deficiency should approximate 0.001.

Adult↗
PubMed1997

Carbon dioxide laser tissue welding: an alternative technique for tubal anastomosis?

Microsurgical tubal anastomosis is the gold standard for treatment of tubal occlusion. The present study was performed to establish the feasibility of tubal anastomosis by welding tissue with a defocused CO2-laser beam during laparotomy and with an endoscope. In an animal experiment, 70 white New Zealand rabbits were randomized in 2 study groups (E1, E2) and 3 control groups (C1, C2, C3) as follows: C1, 10 animals, no operation, as controls for the efficiency of the insemination technique; C2, 5 animals, spontaneous healing after tubal segment resection, to quantify spontaneous recanalization of the tube; C3, 15 animals, microsurgical end-to-end adaption after tubal segment resection; E1, 20 animals, laser welded anastomosis after segment resection via laparotomy; E2, 20 animals, laparoscopic laser welded anastomosis after segment resection. The pregnancy rate in C1 was 80%. None of the animals in C2 but 60% of the rabbits in C3 conceived. After sutureless anastomosis by laser welding 50% of the laparotomized, and 40% of the laparoscopically operated group became pregnant. Morphological examination of the oviducts after relaparotomy showed comparable patency rates of 70% in C3, 70% in E1, and 65% in E2. Whereas no dehiscence of anastomoses was observed in C3, 20% of the welded tubes in E1 and 22.5% in E2 were dehiscent. Tubal anastomosis took approximately three times as long laparoscopically as during laparotomy. Thus, laser welding as a sutureless alternative technique of tubal anastomosis should be viewed critically. A reduction of sutures through laser-assisted anastomosis might, however, be considered.

Anastomosis, Surgical↗
PubMed1997

The complete DNA sequence of the mitochondrial genome of a "living fossil," the coelacanth (Latimeria chalumnae).

The complete nucleotide sequence of the 16,407-bp mitochondrial genome of the coelacanth (Latimeria chalumnae) was determined. The coelacanth mitochondrial genome order is identical to the consensus vertebrate gene order which is also found in all ray-finned fishes, the lungfish, and most tetrapods. Base composition and codon usage also conform to typical vertebrate patterns. The entire mitochondrial genome was PCR-amplified with 24 sets of primers that are expected to amplify homologous regions in other related vertebrate species. Analyses of the control region of the coelacanth mitochondrial genome revealed the existence of four 22-bp tandem repeats close to its 3' end. The phylogenetic analyses of a large data set combining genes coding for rRNAs, tRNAs, and proteins (16,140 characters) confirmed the phylogenetic position of the coelacanth as a lobe-finned fish; it is more closely related to tetrapods than to ray-finned fishes. However, different phylogenetic methods applied to this largest available molecular data set were unable to resolve unambiguously the relationship of the coelacanth to the two other groups of extant lobe-finned fishes, the lungfishes and the tetrapods. Maximum parsimony favored a lungfish/coelacanth or a lungfish/tetrapod sistergroup relationship depending on which transversion:transition weighting is assumed. Neighbor-joining and maximum likelihood supported a lungfish/tetrapod sistergroup relationship.

Amino Acid Sequence↗
PubMed1997

The radiation of characiform fishes and the limits of resolution of mitochondrial ribosomal DNA sequences.

Phylogenetic relationships among fishes from ostariophysan orders, characiform families, and serrasalmin genera (e.g., "piranhas") were examined using partial mitochondrial ribosomal DNA sequences of the 12S and 16S genes. Phylogenetic information content of these sequences was assessed at three levels of taxonomic inclusiveness by analyzing the patterns of nucleotide substitution using secondary structure models. Conserved and variable regions were identified, mapped onto the structural models, and compared at increasing levels of taxonomic divergence. In general, loop regions (unpaired) exhibited a higher level of variation than did stem regions (paired). A high proportion of compensatory substitutions was observed in stem regions in three data sets, suggesting strong selection to maintain the secondary structure. Saturation due to multiple substitutions was indicated by decreasing transition/transversion ratios and strong structural constraints on variation in comparisons among orders of Ostariophysi but was not obvious among families of Characiformes and was not detected among serrasalmin genera. Reliable phylogenetic signal successfully reconstructed relationships among serrasalmin genera. However, aside from a few well-supported clades, relationships could not be reconstructed with confidence among characiform families and ostariophysan orders. The reciprocal monophyly of African and Neotropical characiform lineages was rejected (based on maximum likelihood ratio tests), and some support for previous hypotheses based on morphology was provided by the molecular data. The radiation of characiform fishes is discussed in a historical biogeographic context.

Animals↗
PubMed1997

How to treat coexistent mental illness and substance abuse.

Integration of mental illness and substance abuse treatments is important for patients with "dual diagnosis", the coexistence of an emotional ailment and a chemical dependency. Such comorbidity is usually associated with a poor prognosis. Both disorders require appropriate therapy so that remission of psychiatric symptoms and maintenance of sobriety become reachable goals for these individuals. A joint therapeutic approach improves outcome, functional expectation, and community adjustment.

Comorbidity↗
PubMed1997

Multiple extracellular domains of CCR-5 contribute to human immunodeficiency virus type 1 entry and fusion.

Human immunodeficiency virus type 1 (HIV-1) entry is governed by the interaction of the viral envelope glycoprotein (Env) with its receptor. The HIV-1 receptor is composed of two molecules, the CD4 binding receptor and a coreceptor. The seven-membrane-spanning chemokine receptor CCR-5 is one of the coreceptors used by primary isolates of HIV-1. We demonstrate that the mouse homolog of CCR-5 (mCCR-5) does not function as an HIV-1 coreceptor. A set of chimeras of human CCR-5 and mCCR-5 was studied for Env-induced cell fusion and HIV-1 infection. Using the HIV-1ADA envelope glycoprotein in a syncytium formation assay, we show that replacement of any fragment containing extracellular domains of mCCR-5 by its human counterparts is sufficient to allow Env-induced fusion. Conversely, replacement of any fragment containing human extracellular domains by its murine counterpart did not lead to coreceptor function loss. These results show that several domains of CCR-5 participate in coreceptor function. In addition, using a panel of primary nonsyncytium-inducing and syncytium-inducing isolates that use CCR-5 or both CXCR-4 and CCR-5 as coreceptors, we show that the latter dual-tropic isolates are less tolerant to changes in CCR-5 than strains with a more restricted coreceptor use. Thus, different strains are likely to have different ways of interacting with the CCR-5 coreceptor.

Amino Acid Sequence↗
PubMed1997

South African communities' perceptions and priorities for well-being.

Surveys were conducted using a pre-tested questionnaire in 1991 and 1993 in South Africa to find out how the people perceive the government's social responsibility with special reference to the provision of free health care and other determinants of well-being. Provision of jobs for the unemployed and free education were identified to be the main priorities. Free health care ranked as the fifth priority. The study supports the call for increasing participation of communities in determining and prioritising their needs. It also calls on health care professionals to support the communities by advocating for policies that are directed towards the perceived needs of the community and to use the present available resources efficiently.

Adult↗
PubMed1997

Immunoglobulin gene diversification in cattle.

Research in several species has revealed that different types of mammals have evolved divergent molecular and cellular strategies for generating immunoglobulin diversity. Other chapters in this text have highlighted the specific characteristics unique to chicken, rabbit, mouse, human and sheep B lymphocyte development; namely indicating differences in the mechanisms of diversity and the site of primary B cell development. Studies of the bovine system have indicated that like the sheep system, the ileal Peyer's patch (IPP) is a likely chicken bursal equivalent, and is a site of primary B lymphocyte development. Substantial investigation in sheep has indicated that Ig diversity is created by untemplated somatic mutation and intense selective pressure (Reynaud et al., 1991). The frequency of alteration in the sheep Ig light chain gene locus also is characteristic of the bovine system, however, recent evidence from sequencing of bovine lambda light chain genes indicates that one mechanism that contributes to diversity is gene conversion, utilizing several pseudogenes located in the Ig locus (Parng et al., 1996). The mechanism by which this hyperalteration of Ig genes occurs in both sheep and cattle is poorly understood and is thus the focus of considerable investigation. The study of events in the IPP may also have informative ramifications for secondary diversification of the Ig repertoire by somatic hyperalteration in germinal centers.

Amino Acid Sequence↗
PubMed1997

Criteria for nonoperative treatment of significant penetrating renal lacerations.

PURPOSE: We developed criteria for nonoperative treatment of penetrating renal injuries and predicting which patients will benefit from immediate surgery. MATERIALS AND METHODS: We reviewed the records of 120 patients with grades 2 to 4 renal lacerations from gunshot and stab wounds, of whom 41 were treated nonoperatively (group 1) and 79 underwent immediate renal exploration (group 2). RESULTS: Group 1 had significantly lower incidences of gunshot wounds, shock, associated injuries, need for transfusion and high grade renal injuries. In patients with grade 2 lacerations no complications resulted from nonoperative treatment. However, 23.5% of patients in group 1 with grades 3 and 4 injuries had delayed renal bleeding versus none in group 2. CONCLUSIONS: Nonoperative treatment of penetrating renal lacerations is appropriate in hemodynamically stable patients without associated injuries. Grade 2 injuries can be treated nonoperatively but grades 3 and 4 injuries are associated with a significant risk of delayed bleeding if treated expectantly. Exploration should be considered if laparotomy is indicated for other injuries.

Adolescent↗
PubMed1997

[Gastrointestinal hemorrhage and diverticula of the jejunum--presentation of a case report and review of the literature].

Gastrointestinal bleeding due to jejunal diverticulosis is an uncommon emergency condition that has been encountered recently in one patient. The case of this patient treated with an emergency laparotomy and a segmentary small bowel resection is here presented. The clinical significance, proper diagnostic evaluation, and treatment of the hemorrhagic complication of jejunal diverticular disease are reviewed.

Aged↗
PubMed1997

[Ambulatory sports in asthma improves physical fitness and reduces asthma-induced hospital stay].

Physical training is a well established method in the rehabilitation of patients with chronic obstructive pulmonary disease. In adult asthmatics its efficacy has been shown by intensive training programmes lasting for 2-12 weeks. No data exist on the effect of long-term physical training once a week. 31 patients (f = 24, m = 7; mean age 55 +/- 2 years; mean FEV1.0 82 +/- 4% pred.) participated in a physical training programme for at least 2 years. (8 patients had mild, 12 moderate and 11 severe asthma according to the International Consensus Report of 1993 [13]). Training time was 1 hour per week. The physical training programme consisted of breathing techniques like pursed-lip breathing and diaphragmatic exercise, progressive muscle relaxation, circuits and endurance training. According to the health insurance records 9 patients had been hospitalised for their disease two years prior to the study for a total number of 218 in-hospital days. During the 2 years of the study 2 patients had been hospitalised for a total number of 29 days (p < 0.001). A comparison group of 10 patients who did not participate in the rehabilitation programme had been hospitalised for their disease two years prior to and during the study period for a total number of 236 and 201 in-hospital days (p > 0.2). In a subgroup of 9 patients bicycle exercise testing was performed once a month and work load at a submaximal heart-rate (200-age) was recorded. During the two years mean work rate improved from 48 watts to 83 watts for 15 minutes (p < 0.01). We conclude from our findings that long-term physical training of adult patients with asthma in an outpatient setting once a week is effective in reducing hospitalisation days as well as in increasing cardiorespiratory fitness.

Adult↗
PubMed1997

Lethal maternal sepsis caused by Campylobacter jejuni: pathogen preserved in placenta and identified by molecular methods.

Campylobacter jejuni is one of the most common organisms in the etiology of febrile diarrhea. Bacteremia is reported to be rare. In pregnant women, however, C. jejuni (previous name, Vibrio fetus) can cause fetal death. We report the case of a pregnant woman with enterocolitis and sepsis that caused the death of the fetus and, 11 days later, the death of the mother. C. jejuni was detected by culture techniques at the time of the first symptoms but not during the subsequent course of disease. Bacteria were detected by silver staining and electron microscopic examination in the placenta, but for identification, we used molecular methods. From formalin-fixed, paraffin-embedded placental tissues, a part of the bacterial 16S rRNA was amplified by broad-range polymerase chain reaction, which resulted in a 461-nucleotide sequence. Direct sequencing and comparison to reference sequences revealed C. jejuni as the causative agent for the sepsis and deaths. With this approach, the adverse outcome could be related etiologically to the same infectious agent identified at the onset of the disease. From this and other recent reports, we conclude that C. jejuni must be considered an important pathogen in pregnancy.

Adult↗
PubMed1997

[Resuscitated--then what?].

The outcome of reanimation efforts by the emergency paramedics service and our hospital in 1994-1995 are presented in a retrospective analysis. Of 123 reanimation attempts, 34 (27.6%) were successfully carried out at the scene of injury. A total of 13 patients (10.6%) survived without cerebral damage. Three (2.4%) patients were transferred to a rehabilitation clinic with severe neurological deficiencies. The collective total survival rate was therefore 15.5%. The emergency assistance time of 4.6 minutes for the successful reanimation attempts was significantly shorter than the 7.5 minutes average time frame for the unsuccessful reanimation attempts. This clearly underscores the significance of an efficient emergency paramedic service and first aid training. The prognosis for a reanimated patient is primarily dependent upon the degree of brain damage incurred. Therefore, neuroprotectionary measures are of utmost importance. Valid general standards, however, do not exist. At the present time a mild hypothermic treatment is of special interest.

Adult↗
PubMed1997

[Ring recurrence of ciliary body melanoma after proton-beam therapy].

A malignant ciliary body melanoma was treated by proton-beam irradiation. Ring-shaped recurrence with extraocular extension appeared thirty-six months later and required enucleation. Histologic study revealed a predominant epithelioid cell type tumor, flattened in previously treated area. Proton-beam irradiation efficiency depends on clinical evaluation, which remains questioned in ciliary body locations where circumferential extension could be misevaluated.

Aged↗