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Biomedical subjects

A Lefevre

Publications and source records attributed to A Lefevre.

At least 37 records · Page 2Linked to original sources
PubMed1991

[Hantaan virus infection in Twente].

OBJECTIVE: To find out if Hantavirus infection, as a cause of acute renal failure, has been overlooked in the past. To determine if Hantavirus can be found in wild rodents, particularly in red bank voles (Clethrionomys glareolus), living in the area. SETTING: General hospital, Twente area. PATIENTS, MATERIAL AND METHODS: Retrospective selection of patients, hospitalised between 1970 and 1989 with renal failure due to biopsy-proven or clinically probable acute interstitial nephritis of unknown aetiology. Sera from the acute phase of the disease, if still available, or sera taken in 1989 were tested for anti-Hantavirus antibodies. Red bank voles, trapped in the area were tested for Hantaviral antigen and specific antibodies. RESULTS: Out of 12 patients, 10 could be investigated. Anti-Hantavirus antibodies were detected in 5 patients. All patients had very probably acquired the infection in the Twente area. In 4 of 10 red bank voles Hantaviral antigen and specific antibodies were found. CONCLUSION: The findings suggest that Hantavirus infections have been occurring in this area over a long period of time and are underdiagnosed.

Acute Kidney Injury↗
PubMed1986

Systematic shut-off of the hormone receptors in intraspecific adrenal x Leydig cell hybrids.

The mouse Y1 adrenal cell line was fused with mouse Leydig cells in primary culture. The selected hybrids were examined for their response to gonadotropin (hCG) and ACTH. None of them bound specifically [125I]hCG, nor did they augment their cAMP production in response to gonadotropin or ACTH stimulation, whereas their adenylate cyclase remained responsive to forskolin and cholera toxin, thus indicating a repression of hCG receptor synthesis and probably a loss of ACTH receptors, rather than a lesion of the coupling between the hormone receptor complex and the adenylate cyclase. Basal pregnenolone production in 17 hybrids was close to that of Leydig and Y1 cells and was enhanced after 8-bromo adenosine 3',5'-monophosphate (8-Br-cAMP) stimulation in 11 of them. Therefore, the negative control leading to the extinction of both parental functions acts preferentially at the first step of steroidogenesis, i.e., the gene(s) coding for the hormone receptors.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1986

Suppression of cortisol following dexamethasone in demented patients.

Sixty-four nondepressed, carefully selected senile demented inpatients underwent two 1-mg overnight dexamethasone suppression tests (DSTs) separated by 7 days. These patients were in a clinically stable and drug-free state for at least 6 months before testing. The Modified Ischemic Score and ICD-9 criteria for Alzheimer's disease were used to dichotomize subjects into Alzheimer's and multi-infarct types of dementia. Patients with vascular dementias were significantly more likely to evidence DST nonsuppression. Furthermore, DSTs in this group were less reproducible from week to week than DSTs in Alzheimer's patients.

Aged↗
PubMed1984

Electrofusion. A new, highly efficient technique for generating somatic cell hybrids.

A rapid and highly efficient method for generating viable somatic cell hybrids is described. A co-culture of clone ID and CH rodent cell lines was exposed to five successive electric pulses of about 1.5 kV/cm with a duration of 50 musec. This treatment induced extensive cell fusion, and independent hybrid clones were generated with a frequency of 1 X 10(-3), which represents a 100-fold increase over the polyethylene glycol induced fusion. Seventeen of them were propagated in selective medium, karyotyped and analysed for their enzyme markers, in order to establish their hybrid nature.

Animals↗
PubMed1983

The pancreatic polypeptide cells in the human pancreas: the effects of age and diabetes.

Pancreases from insulin-dependent diabetics (IDDM), noninsulin-dependent diabetics (NIDDM), and nondiabetic subjects were analyzed by stereological and morphometrical methods in order to determine the weight of the lobe rich in pancreatic polypeptide (PP) cells in relation to the total weight of the pancreas and the volume density of PP cells in both parts of the gland, those rich and poor in PP cells. In control subjects, neither the relative weight of the lobe rich in PP cells, nor the volume density of PP cells varied significantly with aging. In IDDM and NIDDM, the volume density of PP cells was similar to that observed in control subjects. The total weight of the pancreas was markedly decreased in IDD because of an almost selective atrophy of the lobe poor in PP cells; the relative weight of the lobe rich in PP cells was thus much higher than that in control subjects. A less marked atrophy, restricted to the lobe poor in PP cells, was also observed in NIDDM. It is suggested that PP may exert a local trophic role which protects the lobe of the pancreas rich in PP cells from atrophy in diabetic patients. The results further show that the elevated levels of PP in the plasma of elderly or diabetic subjects cannot be ascribed to a hyperplasia of PP cells.

Adolescent↗
PubMed1981

Modification of steroidogenesis in a mouse adrenal cell line (Y-1) transformed by simian adenovirus SA-7.

Transformation of a steroidogenic mouse adrenal cell line (Y-1) by simian adenovirus SA7 produced a cell line with low apparent steroidogenic activity. The effect of ACTH and cholera toxin on cyclic AMP production was similar in both not transformed and virus-transformed cells and activity of cyclic AMP-dependent protein kinase was also similar in both cells. In transformed cells, cholesterol was metabolized to delta 5-3 beta-hydroxysteroids, mainly 20 alpha-dihydropregnenolone while in not transformed cells, the major metabolites were delta 4-3 ketosteroids (20 alpha-dihydro- and 11 beta-hydroxy-20 alpha-dihydroprogesterone). In both cell lines ACTH increased the metabolism of cholesterol. Further studies with labelled pregnenolone and progesterone revealed a loss of delta 5-3 beta-hydroxysteroid dehydrogenase/isomerase and 11 beta-hydroxylase activity in the transformed cells.

Adenoviridae↗
PubMed1980

[The relation between polyunsaturated fatty acids and cardio-vascular accidents. I. Study of fatty acid components phospholipids].

Blood plasma lipids of women about seventy years old who had suffered from cardiovascular diseases (AVC) were studied and compared with the plasma lipids of women of about the same age without cardiac troubles. A great difference appears in the unesterified fatty acids of the phospholipids from cardiac women: we have observed a decreasing level of polyunsaturated fatty acids with a carbon chain of more than 18 carbons, and a decreasing ratio between the total concentration of the two precursors (linoleic acid omega and alpha-linolenic acid omega 3) and the total concentration of their long chain polyunsaturated derived fatty acids. On the contrary, we did not observe any significant variation of the unesterified fatty acid level in the plasma. The triglyceride and cholesterol levels also were not different between the two groups of patients. The hypothesis of a lack of elongation and of desaturation of linoleic and alpha-linolenic acids by competitive inhibition with oleic acid seems improbable, since the plasmatic concentration of oleic acid was not statistically different.

Aged↗
PubMedDate not supplied

Biological characterization of experimental carbon samples.

The use of carbon is widespread in fields as wide as aeronautics, cars, electricity or electronics. The biomedical applications of carbon are also numerous. The purpose of our work is to test four experimental carbon fibers (A, B, C and D; B being the negative control) to determine the best clinical application. Four tests of cytocompatibility are carried out (cell viability, inflammatory test, cell proliferation and cell morphology). Two different cell lines are used: the L132 cell line (epithelial embryonic pulmonary human cell) and the HaCaT line (human normal spontaneously immortalized skin keratinocytes). The results of the biological tests are compared with those of a carbon fiber sample already marketed as a bandage in the treatment of infected wounds: Actisorb "Plus (J2). The various tests show us that only two experimental samples are slightly cytotoxic (A, D). On the other hand, no sample supports cell adherence. A, B, C and D do not have an inflammatory effect. J2 appears at the same time cytotoxic and inflammatory. Consequently, being given the physical presentation and the biological properties of experimental samples (A, C and D), we intend them for an application in the field of wound healing, as a bandage. Also further experimentation is needed.

Biocompatible Materials↗
PubMedDate not supplied

[Cortisol suppression after dexamethasone administration in patients with dementia].

Sixty-four nondepressed, carefully selected senile demented inpatients underwent two 1.0 mg overnight dexamethasone suppression tests (DSTs) separated by 7 days. These patients had been in a clinically stable and drug-free state for at least six months prior to testing. The Modified Ischemic Scale score and ICD-9 criteria for Alzheimer's disease were used to dichotomize subjects into Alzheimer's and multi-infarct types of dementia. Patients with vascular dementias were significantly more likely to evidence DST nonsuppression, furthermore, DSTs in this group were less reproducible from week to week than DSTs in Alzheimer's patients.

Aged↗