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Biomedical subjects

G Mayer

Publications and source records attributed to G Mayer.

At least 109 records · Page 6Linked to original sources
PubMed1998

Relationship between kidney function, hemodynamic variables and circulating big endothelin levels in patients with severe refractory heart failure.

UNLABELLED: Fluid retention is a major characteristic of symptomatic, progressive heart failure when a main factor implicated in the pathogenesis of renal dysfunction is renal hypoperfusion. This may be a consequence of forward cardiac failure, resulting in a low cardiac output integrating poor left ventricular function secondary to myocardial impairment and increased resistance in the regional renal vasculature secondary to locally released vasoconstrictors, e.g. endothelin. So far, the role of the pulmonary circulation in perpetuating renal dysfunction in heart failure is unclear. METHODS: We investigated the relationship of hemodynamic variables obtained during right heart catheterization and plasma big endothelin levels to renal function variables in 18 male patients aged 52 +/- 3 years, with heart failure in the NYHA function class III-IV, based on idiopathic causes in 8 and ischemic causes in 10 patients. Renal plasma flow (RPF) was established by paraaminohippurate (PAH) clearance and the glomerular filtration rate (GFR) was measured by iothalamate clearance. RESULTS: Plasma big endothelin (ET) levels were increased above the upper normal range (1.8 fmol/ml) in 16 out of 18 patients, averaging 5.0 +/- 0.8 fmol/ml (1.7-11.9 fmol/ml). Positive correlations to big ET plasma levels were detected with mean pulmonary pressure (r = 0.73, p < 0.001) pulmonary capillary wedge pressure (r = 0.56, p < 0.05) and pulmonary vascular resistance index (r = 0.69, p < 0.01). Glomerular filtration rate (70 +/- 7 ml/min) and renal plasma flow (358 +/- 36 ml/min) were considerably reduced and exhibited a tendency to correlate inversely with big ET levels (r = -0.46, p = 0.056 and r = -0.44, p = 0.069, respectively). Contrary to expectations, RPF did not correlate significantly with cardiac index, systemic vascular resistance index or arterial blood pressure. In contrast, significant correlations were detected of RPF with pulmonary capillary wedge pressure (r = -0.69, p < 0.01), mean pulmonary artery pressure (r = -0.65, p < 0.01), right atrial pressure (r = -0.47, p < 0.05) and right ventricular ejection fraction (r = 0.49, p < 0.05). CONCLUSION: The findings suggest a role for endothelin in renal vasoconstriction and accord well with the concept that in severe heart failure renal hypoperfusion--by volume retention--as well as increased endothelin synthesis--by pulmonary vasoconstriction--play a part in the increased pulmonary filling pressures.

Endothelin-1↗
PubMed1998

[Sleep deprivation in somnambulism. Effect of arousal, deep sleep and sleep stage changes].

Diagnosis of parasomnias in the sleep laboratory is difficult since the nocturnal behavior reported by the patients often does not show up in the laboratory. To test the efficacy of sleep deprivation as a tool to provoke somnambulism we investigated ten patients (three women and seven men, mean age 27 +/- 3.4) with somnambulism. Their standard polysomnographies and videomonitored nocturnal behavior was compared to that of sex- and age-matched controls and to polysomnography and behavior after sleep deprivation. Patients with parasomnias and controls did not show significant differences in sleep parameters with the exception of longer arousal duration in controls, which was nonsignificant. In magnetic resonance tomography, patients with parasomnias did not reveal abnormality of the brain that might explain release of nocturnal behavior. Sleep deprivation led to significantly reduced number of arousals, reduced arousal index, significantly prolonged arousal duration and more stage shifts from all sleep stages (nonsignificant). Complex behavior during sleep increased under sleep deprivation, whereas sleepwalking did not increase. The majority of complex behavior during sleep is triggered by stage shifts and not by arousal in the sense of the arousal definition of the American Sleep Disorder Society. Complex behavior in sleep is stereotypical and nonviolent. Its complexity seems to depend on the duration and intensity of arousals. Sleep deprivation can be recommended as an efficacious method of increasing complex behavior in sleep, which is a preliminary stage of sleepwalking. Concerning the underlying pathology it seems to be important to register the quality and duration of stimuli that trigger arousals instead of focusing the number of arousals alone.

Adult↗
PubMed1998

Aprotinin counterbalances an increased risk of peri-operative hemorrhage in CABG patients pre-treated with Aspirin.

OBJECTIVE: As Aspirin (ASA) has proven efficacy in preventing patients with CAD from complications related to cardiovascular diseases, most patients scheduled for CABG are treated with ASA therapy. Consequently, impaired hemostasis is a problem in the management of CABG patients. Clinical studies have shown that Aprotinin can reduce bleeding and the use of blood products by 50% in patients both with and without pre-operative ASA therapy. Concerning the combined effect of peri-operative low-dose ASA therapy and intra-operative high-dose Aprotinin therapy, the gathering of additional and prospective data seemed to be necessary. METHODS: We conducted a double-blind two-centre randomised three-arm study in patients with elective primary CABG surgery. Three groups have been tested, comprising 119 patients in total (group A: ASA + Aprotinin, group B: placebo + Aprotinin, group C: placebo + placebo) to investigate a possible reduction of bleeding in Aprotinin treated patients. For all patients, thromboxane levels were used to identify ASA or placebo treatment. RESULTS: The post-operative blood loss is significantly reduced by 21% after Trasylol administration (B vs. C; P = 0.009). The unexpected result of this study has been that the pre-treatment with ASA led to a further reduction of 18% (A vs. C; P < 0.0001). The difference between the two Aprotinin groups (A and B) is significant (P = 0. 01) in favour of ASA pre-treatment. Myocardial infarction (MI) had been diagnosed at levels of 1.8% in total (2/113), 2.6% (1/38) in group B and 3.2% (1/31 ) in group C. An additional blinded evaluation of ECG, enzyme levels and clinical status revealed 'definite, probable and possible' MIs of 5% in group A, compared to 16% in group B and 13% in group C, thus providing no evidence for a higher risk of infarction by Aprotinin treatment. When comparing the ASA group to non-ASA pre-treatment, a strong trend towards a reduction in MI rate becomes obvious, from 15% to 5% in favour of the ASA pre-treatment (P = 0.08). Concerning other peri-operative complications, no statistical difference between the groups could be detected. CONCLUSIONS: A reduction in post-operative blood loss in primary elective CABG surgery with intra-operative Aprotinin treatment could be confirmed. A low-dose ASA treatment combined with a high-dose aprotinin administration during surgery not only neutralized a potentially higher risk of bleeding, but did in fact reduce the post-operative blood loss. The protective effect of ASA on peri-operative MI has been evident through a reduction of MI rate in ASA treated patients.

Aprotinin↗
PubMed1998

Segregation of HLA genes in multicase narcolepsy families.

In the past 15 years, 411 sporadic narcolepsy patients have been diagnosed in the Hephata Klinik, Schwalmstadt, Germany. They were explored for presence or absence of excessive daytime sleepiness and narcolepsy in their relatives. A subset of 39 patients were explored for presence or absence of parasomnias. Six patients had more than one relative affected by narcolepsy-cataplexy. Forty-seven family members were investigated with the Stanford Center for Narcolepsy Sleep Inventory and a standardized parasomnia questionnaire. Twenty-four relatives had nocturnal polysomnographies and Multiple Sleep Latency Tests. HLA class I typing was performed in all sporadic and familial cases, class II and microsatellite typing was performed in all members of multicase families. Based on the Finnish prevalence study by Hublin et al., 1994, the relative risk for first degree relatives to develop narcolepsy-cataplexy was in our sample 16.5, 34.2 for excessive daytime sleepiness and 426.9 for parasomnias. Cataplexy, excessive daytime sleepiness and single narcoleptic symptoms in the multicase families segregate with the DRBI*1501, CARII:200, CARI: 103, DQBI*0602 haplotype. In two families, members with narcolepsy and isolated symptoms have inherited the DRBI*1501/DQBI*0602 haplotype from the nonaffected parent. The observed segregations in these two families may support the view that narcoleptic symptoms are expressed by DRBI*1501/DQBI*0602 carriers, independent of haplotype origin. Parasomnias do not segregate with a specific haplotype. The frequency of parasomnias in narcolepsy is much higher than in the general population. The empirical risk for first degree family members of narcolepsy patients to develop cataplexy seems to be low, whereas it is higher for EDS and highest for parasomnias.

Adult↗
PubMed1998

Adrenal function in patients with chronic renal failure.

Previous studies have reported divergent findings on the function of the hypothalamic-pituitary-adrenal axis in patients with chronic renal failure (CRF). The low-dose adrenocorticotropin (ACTH) test offers the possibility of unmasking adrenal dysfunction, which might remain undiscovered using the ACTH test with the standard 250-microg dose. Furthermore, the choice of renal replacement therapy (either hemodialysis or continuous ambulatory peritoneal dialysis [CAPD]) might have an impact on adrenal function. To investigate these possibilities, ACTH tests were performed with three different doses (ie, 1, 5, and 250 microg) in 14 CRF patients and in seven healthy controls. Seven of the CRF patients were receiving chronic hemodialysis and seven were receiving CAPD. Basal plasma concentrations of cortisol were comparable in the three groups tested (5.3+/-0.4 microg/dL in the controls, 6.6+/-0.7 microg/dL in the hemodialysis patients, and 7.9+/-1.0 microg/dL in the CAPD patients), whereas basal ACTH concentrations were significantly elevated in the CRF patients (28.5+/-3.8 pg/mL in the hemodialysis patients and 33.0+/-6.0 pg/mL in the CAPD patients) when compared with normal controls (17.0+/-1.4 pg/mL; P < 0.05). All three doses of ACTH resulted in a rapid increase of plasma cortisol concentrations that was comparable in all three groups. In the hemodialysis patients, a trend toward a diminished response to the lowest dose of 1 microg was noticed. We conclude, therefore, that adrenal response to ACTH in various doses is unaffected in CRF independent of whether hemodialysis or CAPD is chosen for renal replacement therapy.

Adrenal Glands↗
PubMed1998

Plasma immunadsorption treatment in patients with primary focal and segmental glomerulosclerosis.

BACKGROUND: In primary focal and segmental glomerulosclerosis (FSGS) renal prognosis is poor if no remission of proteinuria can be obtained by treatment. In some patients a permeability factor, responsible for damaging the glomerular epithelial cell and detectable by an in vitro test (GVV-test), seems to be present in the serum. METHOD: We determined the effects of an immunadsorption treatment (IAT) on proteinuria and glomerular permselectivity (using a neutral dextran and dextransulfate-sieving technique to assess glomerular size and charge selectivity) in five patients with FSGS in the native kidneys and three patients with recurrence of FSGS after kidney transplantation. Furthermore, we performed the GVV-test using sera obtained from the patients before and after therapy. RESULTS: IAT reduced proteinuria by more than 50% in four patients, all of whom had an improvement in glomerular-size selectivity. Charge selectivity was better preserved after therapy in three out of these four subjects. The GVV-test prior to IAT was positive in two patients who also responded clinically to therapy. After IAT the GVV-test was negative in all patients, indicating an elimination of the proteinuric factor in the two previously positive patients. CONCLUSION: We conclude that a positive GVV-test before treatment makes a favourable response of IAT on proteinuria likely in patients with FSGS. If a reduction of proteinuria can be obtained by IAT this is due to an improvement in glomerular size and/or charge selectivity.

Adolescent↗
PubMed1998

Angiotensin-converting enzyme gene polymorphism determines the antiproteinuric and systemic hemodynamic effect of enalapril in patients with proteinuric renal disease. Austrian Study Group of the Effects of Enalapril Treatment in Proteinuric Renal Disease.

Angiotensin-converting enzyme (ACE) inhibitors are known to reduce blood pressure and proteinuria in a variety of different glomerular diseases. Nonetheless, a marked interindividual difference in the efficacy of these agents exists. The activity of the ACE and therefore of the renin-angiotensin-aldosterone system (RAAS) has been shown to be under genetic influence. Patients with a deletion genotype at the intron 16 of the ACE gene have been shown to exhibit higher activity of plasmatic ACE when compared to patients with the insertion genotype. We therefore studied prospectively the hemodynamic and antiproteinuric effect of a 6-month therapy with enalapril in patients with biopsy-proven proteinuric glomerular diseases and the DD (n = 10) and ID/II (n = 26) genotype. Although patients with the DD genotype received a slightly higher dose of enalapril, blood pressure and proteinuria did not change significantly. However, both were significantly reduced in the II/ID group after 10 weeks and 6 months of therapy. Creatinine clearance decreased steadily in DD patients. In II/ID patients, creatinine clearance was reduced significantly after 10 weeks of therapy but increased again thereafter and the value at 6 months was again comparable to the one obtained in the DD patients. We conclude from our study that the ACE genotype influences the blood pressure-lowering and antiproteinuric effect of enalapril in patients with proteinuric glomerular disease.

Adult↗
PubMed1998

Endemic goitre: a research protocol elaboration for eradication.

The iodine deficiency (ID), which affects 1 person out of 6, is relatively neglected by the responsible of Public Health Service, particularly in developing countries. Consequences of ID are far from being negligible: mental retardation, hypofertility, hyperplasia, carcinoma, early ageing and, in very exposed areas, endemic cretinism. Nevertheless, eradication is easy and cheap but it requires rigorous protocols and control of results. The elaboration of these protocols is complex because it must be adapted to environment, population and financial possibilities of concerned countries. Based on our experience in this field, we propose a combined protocol, between the Public Health too liberal approach and that of too expensive research, which can be adapted to several situations.

Data Collection↗
PubMed1998

Genetic factors in iodine deficiency disorders: a general review.

This review presents a summary of what is known about genetic factors possibly involved in iodine deficiency disorders. After an overview on thyroid iodine metabolism and the role of environmental factors in endemic goitre, we analyse genetic studies on endemic goitre reported in the literature. We hypothesize that endemic goitre is a multifactorial disease in which the major factor would be of environmental nature (iodine deficiency) with a lesser role for genetic factors. Mutations, in a heterozygote state, of one of the genes involved in tiered hormonogenesis could lead to a less effective metabolic pathway in the iodine transport or hormonogenesis. We also briefly review various hereditary disorders which may be involved in endemic goitre. Then, we postulate that the presence of some genetic variants in the population or the heterozygote status of individuals for thyroid hereditary disorders may influence the degree of the thyroid enlargement and/or hypothyroidism.

Goiter, Endemic↗
PubMed1998

Thyroid and fertility.

The aim of this work is to specify the relationship between the thyroid function and the hypothalamo-hypophyso-gonadal axis. Qualitative and quantitative repercussions of a thyroid pathology on human or animal fertility, male or female are very variable. A review of mechanisms of action is presented, illustrating: the complexity of the phenomena in cause; the necessity not to dissociate thyroid and reproductive function either clinically or biologically; the serious consequences of either undetected or untreated neo-natal thyroid pathology.

Animals↗
PubMed1998

The prevalence of goitre and cretinism in a population of the west Ivory Coast.

Iodine deficiency is a major public health problem in developing countries. The main areas where goitre is prevalent have been identified, but the different degrees of severity and the populations affected have not. Most countries are now attempting to obtain reliable and more extensive data. A pilot study was carried out in the Ivory Coast in order to improve epidemiological knowledge of iodine deficiency and collect the information required to set up an elimination programme. The aim of this study was to assess the prevalence of goitre and cretinism and to measure the main biochemical indicators of thyroid function (T3, T4 and TSH). The study involved 1433 people identified from a census. The prevalence of goitre was 50.3%. There was a significant difference between the examined ethnic groups: 52.7% of the Yacouba and 28.6% of the non-Yacouba had goitre. The most affected age group was 15-45 year. The predominance of women demonstrated the susceptibility of women at child-bearing age to develop the condition. The prevalence of cretinism was approximately 1.5%. Through the assessment carried out using a grid of clinical indicators, it was possible to identify 10 cases of laboratory proven myxedematous cretinism due to hypothyroidism. The concentration of iodine in foodstuffs was below the limit of detection (< 7.5 micrograms/kg) and iodine could not be detected in the water (< 1 microgram.l) The biological profile of the population was affected to a very limited extent, with a mean value (+/- standard deviation) for TSH of 1.93 (+/- 1.56) mIU/l (0.1-4.0) and a free T4 value of 10 (+/- 3.46) pmol/l (8.2-20). These initial results confirm the high prevalence of endemic goitre and the low iodine content of the soil, water and food in the investigated region. The study will be complemented by a nutritional investigation to improve the understanding of iodine balance, after which an appropriate action plan will be proposed.

Adolescent↗
PubMed1998

Detection of HIV-1 infection in dried blood spots from a 12-year-old ABO bedside test card.

BACKGROUND AND OBJECTIVES: We tested dried blood from an ABO bedside test card which had been stored at room temperature for 12 years, to prove that a patient with HIV-1 infection had been infected by blood transfusion. MATERIALS AND METHODS: Immunoblots for HIV-1 antibodies and threefold PCRs with half-nested primers for the HIV-1 integrase gene were done with eluates from the dried blood spots. RESULTS: HIV-1 antibodies and HIV-1 DNA could be detected in the sample from one unit of blood, but not from the two other units or from the recipient before transfusion. CONCLUSION: Further studies should be done on the validity of stored dried blood as an alternative to the storage of frozen donor serum for several years for 'look-back' studies.

ABO Blood-Group System↗
PubMed1997

Evaluation of risk factors for the development of nephropathy in patients with IDDM: insertion/deletion angiotensin converting enzyme gene polymorphism, hypertension and metabolic control.

Diabetic nephropathy represents a major complication in patients with insulin-dependent diabetes mellitus (IDDM). Intervention trials using angiotensin-converting enzyme (ACE) inhibitors have pointed towards the important pathogenetic role of the renin-angiotensin system. Recently an insertion/ deletion (I/D) polymorphism for the gene encoding the ACE has been described, the deletion type being associated with higher plasma ACE levels. As the intrarenal renin-angiotensin system might also be activated in this setting, we determined the ACE genotype together with other risk factors for the development of diabetic nephropathy in 122 patients with IDDM from a single centre with (n = 63) and without (n = 59) nephropathy. Long-term glycaemic control was evaluated using mean HbA1c values from the last 10 years. The two patient group were comparable with regard to duration of diabetes and glycaemic control as assessed by current HbA1c values. However, mean long-term HbA1c values were significantly higher in patients with diabetic nephropathy as was systemic blood pressure. The DD genotype was more prevalent in patients with renal disease. In the subgroup of patients who had had diabetes for more than 20 years (n = 90), the DD genotype was even more frequent in patients with nephropathy, and blood pressure and long-term HbA1c values were also higher in patients with renal disease. Logistic regression analysis revealed long-term glycaemic control, blood pressure and the ACE genotype to be independent risk factors for the prevalence of diabetic nephropathy.

Blood Glucose↗