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Biomedical subjects

H Beck

Publications and source records attributed to H Beck.

At least 271 records · Page 15Linked to original sources
PubMedDate not supplied

A long-term toxicity test comprising reproduction and growth of zebrafish with 4-chloroaniline.

This study describes a long-term test over three generations, using zebrafish (Brachydanio rerio) as the test species and concentrations of 1, 0.2, and 0.04 mg/L 4-chloroaniline (CA) as a model substance. The effect of the compound on the ecologically important parameters reproduction and growth was the focus of interest. Reduction in egg release by fish raised under CA was the most sensitive parameter in the test. Compared to the toxic threshold concentration for growth (0.4 mg/L), egg release was affected by a ten-fold lower concentration (0.04 mg/L). This study demonstrates that a long-term test is still the most appropriate method to assess the chronic toxicity of a substance on fish. A chronic toxicity test is proposed which comprises two generations, with the zebrafish as test species.

Aniline Compounds↗
PubMedDate not supplied

Pharmacokinetics of oxiracetam in elderly patients after 800 mg oral doses, comparison with non-geriatric healthy subjects.

The pharmacokinetics of oxiracetam have been studied in eighteen elderly patients and in six healthy non-geriatric adults. A 800 mg single oral dose was administered in the morning of the first day and repeatedly, every 12 h, from day 2 evening to day 10 morning, to the elderly patients. The healthy non-geriatric adults were given a 800 mg single oral dose of oxiracetam. In healthy non-geriatric subjects after a single oral administration of 800 mg, the normalized plasma levels of oxiracetam for 1 mg/kg dose were similar to those already recorded after a 2000 mg single dose of oxiracetam. Therefore, there was no tendency towards non-linear pharmacokinetics of oxiracetam between 800 and 2000 mg single doses in healthy subjects. After the single oral dose, the mean area under the plasma concentration-time curve of oxiracetam in elderly patients was increased by a factor of two as compared to that observed in non-geriatric healthy subjects whereas the maximum concentration (Cmax) was almost not modified and slightly delayed. This can be explained by a slower absorption and elimination in the elderly patients. The highest oxiracetam levels were predominantly recorded in the oldest patients. The slower elimination (mean T1/2 = 12.3 h in elderly and 7.7 h in healthy subjects) could be attributed to a physiological decrease of the renal function. The volume of distribution was not significantly modified in the elderly patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMedDate not supplied

Tissue distribution, toxicokinetics and induction of hepatic drug metabolizing enzymes in male rats after a single s.c. dose of 3,4,3',4'-tetrachlorobiphenyl (PCB-77).

The tissue distribution and toxicokinetics of PCB-77 after a single s.c. dose of 6 mg/kg body weight was investigated in male adult rats as well as the concurrent induction of hepatic drug-metabolizing enzymes. During five days after treatment, the PCB-77 concentrations on fat weight basis in testis and in whole blood were found to be about in the same range as the concentrations in adipose tissue, whereas in liver fat PCB-77 accumulated. EROD and MROD activities were induced by about 8 and 4 times, respectively, during a period of two weeks after treatment. Concentrations in adipose tissue and in liver as well as the hepatic enzyme activities rapidly declined during the investigation period of eight weeks. An elimination half-life for PCB-77 of approximately 7-9 days was estimated.

Adipose Tissue↗
PubMedDate not supplied

[Endoprosthetic management of patients with hip arthrodesis].

PURPOSE: Purpose of this retrospective study was to investigate the long-term results of total hip replacement in patients with hip arthrodesis. METHODS: Between 1976 and 1986 conversion of a earlier performed arthrodesis of the hip to total hip replacement was carried out in a total of 20 patients. 15 of these have been followed up postoperatively for an average of 15.7 years. The main preoperative symptoms were pain affecting the lumbar spine, the ipsilateral knee and/or both hip joints. In two cases, the arthrodesis has fractured. RESULTS: With the exception of one female patient, all the patients expressed satisfaction with the postoperative results, pain having been alleviated or eliminated. The difference in leg length presenting preoperatively in 12 patients was partly or completely equalized in ten cases. Specific physiotherapy over a period of several months resulted in an appreciable increase in muscular power in all patients. Postoperatively ten patients had a slight, five a pronounced limp, while 11 patients needed a walking aid. Recurrent dislocations occurred in one patient. We observed one aseptic loosening of the cup after 10 years. CONCLUSION: The results of the study show that conversion of surgically ankylosed hip joints to total hip replacement makes good sense. Provided that the indication is established with care, this major surgical procedure represents a suitable method, not only of improving the patient's quality of life, but also, and in particular, of at least appreciably improving the symptoms developing after hip arthrodesis. There seems no increased rate of aseptic implant loosening.

Adolescent↗
PubMedDate not supplied

[Radiation therapy in the prevention of periarticular, heterotopic ossification following implantation of a total hip endoprosthesis].

From June 1988 to January 1991 the efficacy of a low-dose (5 x 2 Gy) versus a high-dose (10 x 2 Gy, resp. 5 x 3,5 Gy) prophylactic postoperative radiotherapy was assessed in a prospective randomized trial. 60 patients at the highest risk for formation of heterotopic ossification (HO) were included in this study, i.e. patients that presented already HO in the ipsi- or contralateral hip at the time of surgery. After both irradiation regimen the incidence and severity of HO was significantly less than without prophylaxis; there was no significant difference (regarding the severity of HO, the hip score (16) and the hip mobility) between the two regimen.

Adult↗
PubMedDate not supplied

Differential peptide binding motif for three juvenile arthritis associated HLA-DQ molecules.

OBJECTIVE: In the oligoarticular subgroup of juvenile idiopathic arthritis, a strong association has been found with the expression of human leukocyte antigen class II molecules HLA-DQA1 *0401-DQB1*0402 and DQA1*0501-DQB1*0301, whereas DQA1*0501-DQB1*0201 is neutral and DQA1 *0201-DQB1*0201 protective. A presentation of different peptides by these DQ alleles would support their role in the disease process. METHODS: Using a synthetic nonapeptide library, a peptide binding motif was determined for the associated DQA1*0501-DQB1*0301 molecule and compared to the neutral and the protective DQ molecules. RESULTS: A differential motif for the three molecules could be deduced, suggesting that peptides preferentially binding to the associated vs. the neutral/protective DQ-molecules are mutually exclusive. CONCLUSION: These results imply a role for differential peptide presentation in the pathogenesis of oligoarthritic JIA. The search for peptides initiating the disease process might be facilitated which could then lead to therapeutical interventions.

Arthritis, Juvenile↗
PubMedDate not supplied

Antibody response to anti-A/New Jersey/76 vaccines.

Experimental inactivated influenza vaccines prepared with strain X 53, derived from A/New Jersey/76 virus were injected to several groups of subjects. Different compositions of vaccine were used and the subjects were selected from different age groups. Antibody responses were measured 15 days after vaccination; it was then possible to evaluate the conversion rates, the percentages of subjects showing a protective level of antibodies and the average level of antibodies. The results show that a very small dose of antigen, probably acting as a booster, gives very good results in the older age group. On the other hand, young adults (below 23) react to a much lower degree to the vaccine. The results are discussed in relation to the age distribution of preexisting antibodies in the experimental groups and in the general population in France.

Adult↗
PubMedDate not supplied

Effects of vaccination on an influenza epidemic in a geriatric hospital.

During winter 75/76 (from February 1 to March 31) we got the opportunity to follow the incidence of an influenza epidemic that occurred in the geriatric hospital of Ivry. Its population was, on the average, 83 years old. 958 persons were involved in this study: 523 out of them had been vaccinated with Pasteur bivalent Mutagrip A + B vaccine. The epidemic had a double origin: it was due to a virus A/Victoria and to a virus B/Hong Kong. A significant difference was noted between the vaccinated group and the nonvaccinated one. Serological (CF and HI) and virological investigations (virus isolation) were performed on 110 subjects. The clinical course followed by the disease was mild for the vaccinated and severe for the nonvaccinated. Mortality rate was 0.19% in the former against 3.90% in the latter. It has been thus possible to observe an "immunological fence" since it appears that when 79% of a given unit has been vaccinated, influenza incidence has been as much as three times reduced.

Aged↗