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Biomedical subjects

M Philbert

Publications and source records attributed to M Philbert.

At least 19 recordsLinked to original sources
PubMed1992

1-Methyl-4-(2'-ethylphenyl)-1,2,3,6-tetrahydropyridine-induced toxicity in PC12 cells is enhanced by preventing glycolysis.

The effects of 1-methyl-4-(2'-ethylphenyl)-1,2,3,6-tetrahydropyridine (2'Et-MPTP), 1-methyl-4-(2'-ethylphenyl)pyridinium (2'Et-MPP+), and the classic complex 1 inhibitor, rotenone, on toxicity as well as on rates of glucose use and lactate production were studied using the pheochromocytoma PC12 cell line. PC12 cells are neoplastic in nature and have a high rate of glycolysis accompanied by a large production of lactate and a low use of glucose carbon through the Krebs cycle. 1-Methyl-4-phenylpyridinium (MPP+) and analogues such as 2'Et-MPP+ are actively accumulated by mitochondrial preparations in vitro and block NADH dehydrogenase of complex 1. This blockade results in biochemical sequelae that are ultimately cytotoxic. In this study, untreated PC12 cells used glucose and concomitantly accumulated lactate in a time-dependent manner at all concentrations of glucose studied. Treatment with 50 microM 2'Et-MPP+ or 50 nM rotenone increased both rates significantly, indicating a shift toward increased glycolysis. Cell death caused by the neurotoxins was also time and concentration dependent and markedly enhanced by glucose depletion in the medium. The increase in 2'Et-MPTP-induced toxicity in low glucose-supplemented cells was not due to an increase in pyridinium formation from the tetrahydropyridine, but rather to the lack of glucose for glycolysis. Moreover, inhibition of glycolysis with 2-deoxyglucose or iodoacetic acid also enhanced the lethality of the neurotoxins to the cells. The data in this study provide additional support to the hypothesis that 2'Et-MPP+ or related analogues act to kill cells by inhibiting mitochondrial respiration.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1988

Allergy and occupational exposure to hydroquinone and to methionine.

Respiratory manifestations have been reported after exposure to hydroquinone and to methionine. One hundred and three men in the same chemical plant were divided into three groups according to their exposure and compared by questionnaire, respiratory functional tests with methacholine then salbutamol challenges, and measurements of serum immunoglobulins G and E. Group H included 33 workers exposed to hydroquinone, trimethyl-hydroquinone, and retinene-hydroquinone. Group M included 15 workers exposed to methionine. Group C was a control group of 55 workers. The prevalence of respiratory symptoms was higher in the two exposed groups. Before challenges, pulmonary function values were significantly lower in groups H and M than those in group C. The challenges induced significant variations in the three groups but these variations were less pronounced in group M than in the other groups. The level of immunoglobulin G in group H (m +/- SD = 12.5 gram/liter +/- 2.6) was significantly higher than in group C (10.6 gram/liter +/- 2.4; p less than 0.002). The level of immunoglobulin E in group H (m = 140 IU/l) was also higher in group C (109 IU/l) but this difference was not significant. These findings suggest that exposure to methionine and to hydroquinone and its derivatives induce ventilatory impairment, perhaps by an immunological mechanism.

Adult↗
PubMed1987

Variation of lung function during the workshift among cotton and jute workers.

Cotton and jute dust exposure is known to induce reversible airway obstruction. We compared 50 exposed workers to 99 non exposed workers for the prevalence of respiratory symptoms and ventilatory impairment, and for variations in pulmonary function after five working days and after inhalation of salbutamol. The prevalence of respiratory symptoms was not significantly different between the two groups. Pulmonary function was not different on Monday morning, however, significant differences were observed on Friday afternoon. The exposed workers had a lower flow rate at 75% of exhaled forced vital capacity than controls (P less than 0.01). Salbutamol induced greater bronchodilatation in the exposed group. Comparison with a control group is necessary to take into account the change in pulmonary function. Repeated tests, combined with pharmacological tests, are able to differentiate the lung function pattern of exposed and non exposed workers.

Adult↗
PubMed1975

[Does rheumatic pleuresy exist?].

The authors report the case of a 20 year-old young man with old rheumatic heart disease in whom suddenly occurred sero-fibrinous pleurisy with fever. The usual cause of pleurisy, e.g. tuberculosis, were eliminated. On the other hadn, there was considerable evidence, including lengthening of the P-R interval, and raised anti-streptolysin titer at 1920 units, which suggested recurrence of rheumatic fever. The relationship between this disease and sero-fibrinous pleurisy is then discussed.

Adrenal Cortex Hormones↗
PubMed1975

[2 cases of hepatorenal polycystosis].

The authors report two cases of polycystic liver andkidney in two women. They were unusual in that the liver first gave risr to symptoms and the renal lesions were completely latent. Both hepatic and renal lesions were well tolerated in spite of hepatomegally. They emphasize the interest of laparoscopy and biopsy of the liver under direct vision, and selective aortography, in the diagnosis. They discuss the basic differences between polycystic liver and kidney in adults, from that in children ornewborn, and caroli's disease. Finally, they emphasize the usually poor prognosis dominated by progressive renal failure which should guide treatment. The latter depends on periodic supervision of the patient for the disease usually evolves slowly. Treatment should therefore be conservative. Tn some cases, however, renal transplantaton should be considered before irreversible renal failure in young subjects, at an age when it is still possible. On the other hand, the liver lesions do not require any radical treatment, unless there is intercurrent infection or pressure on neighbouringorgans.

Adult↗
PubMed1975

[Acute non-tuberculous military lung].

The authors report the case of a young woman with acute miliary appearance of the lung with asphyxia, from which she rapidly recovered. No cause was demonstrated; this illustrates the difficulty in diagnosis of this disease. Contact with a bird, led the authors to consider exogenous, allergic granulomatosis, but immunological examinations did not confirm this. Apart from tuberculosis, almost 50 different pathogenic organisms may cause acute respiratory failure associated with a miliary or reticulo-nodular appearance of the lung. The main methods of diagnosis are discussed in relation to the most commonly observed causes in France.

Acute Disease↗