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Biomedical subjects

L Peyrin

Publications and source records attributed to L Peyrin.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

[Biochemical diagnosis of pheochromocytoma and neuroblastomas].

Pheochromocytoma and neuroblastoma are distinct tumours, but their biological diagnosis is based on secretion increase of one or several catecholamines. Assays have to be very sensible and specific for an early diagnosis. 24 hours urinary catecholamines and metabolites are currently measured, but technical improvements permit plasma metanephrine assay, an excellent indicator of pheochromocytoma. HPLC coupled to electrochemical detection represents the most efficient methodology. After a review of urinary and plasma assay methods, the authors show usual values of catecholamines, metanephrines, HVA and VMA, according to ages, and give examples of results encountered in classical or not tumours and in falsely positive cases. Urinary metanephrine assay is the most sensible and specific in biological diagnosis of pheochromocytoma, while catecholamines and VMA assays lack of sensibility. Results have to be given by 24 hours and by creatinine ratio. Metanephrine assay can be performed also in plasma and exhibits the same interest. However, in urine as in plasma, in case of renal failure, results cannot be interpreted. Neuroblastoma biological diagnosis is based classically on HVA, VMA, and dopamine assays, nowadays only in 24 hours urine (or in urinary micturition for screening), and results are also expressed as creatinine ratio. But even if several assays are advisable, 5% of the neuroblastoma cases do not produce increased catecholamine values. In some cases, metanephrine assay could be of interest. After the age of 12 months, clinical expression of neuroblastoma is dramatic in 70% of cases. So, a biological screening has been experimented in several countries including France. A French translation of the consensus conference report (1998) is appended, which shows the complexity of neuroblastoma screening. Now, there is no evidence that early tumour detection by screening lessens the mortality rate, but a weak benefit is not excluded.

Adolescent↗
PubMedDate not supplied

[Importance of urinary 3-O methyldopamine in the metabolism of adrenergic tumors].

Urinary 3-O methyldopamine has been found highly increased in all cases of malignant tumours, as well of sympathetic nature (sympathoblastoma) as of chromaffin type (pheochromocytoma) but at a lesser extent in benign sympathetic tumours (ganglioneuroma). On the other hand, 3-O methyldopamine excretion is normal in benign pheochromocytoma. The ratio of this compound in the dopaminergic block is increased in sympathoblastoma, decreased in ganglioneurona and unchanged in pheochromocytoma. This kind of analysis has not been made for the case of malignant pheochromoblastoma. This ratio of 3-O methyldopamine in the whole dopaminergic and noradrenergic metabolism is increased only in sympathoblastoma. In the other cases (ganglioneuroma and pheochromocytoma) this ratio is decreased. Comparative analysis of urinary 3-O methyldopamine and the two other methoxylated amines (norepinephrine and metanephrine) shows that the methoxylated derivative of dopamine, when compared to normal subjects values, increased at the greatest extent in sympathoblastoma, while in ganglioneurona and chromaffin tumours, normetanephrine is with a variable degree, the predominant compound.

Adult↗
PubMedDate not supplied

[Disorders of noradrenergic pathways in anorexia nervosa. Results].

Twelve patients suffering from mental anorexia were examined on clinical and biological grounds, based on the hypothesis of the functional depression of the noradrenergic track. The initial values of MHPG and of catecholamines were below normal. The quantitative results for depression and retardation were lessened significantly under beta-stimulant treatment. Only glucuro-conjugate MHPG excretion increased significantly, but the MHPG values were much lower than normal at the end of the treatment. The correlations between biochemical and behavioural parameters were worth noticing as far as the retardation scale was concerned. The present study shows the advantage of the dexamethasone suppression test and of the response of TSH under TRH.

Adolescent↗
PubMedDate not supplied

[Selective study of sulfate and glucuronide conjugates of urinary MHPG in nervous depression. Peripheral and central influences].

The determination of urinary MHPG (3-methoxy-4-hydroxyphenyl glycol) has been extensively performed to confirm the noradrenergic hypothesis of some depressions. However, owing to the double origin, central and peripheral, of this norepinephrine metabolite, the validity of total MHPG assay as an index of central noradrenergic activity may be challenged. MHPG exists in human urine in two conjugated forms, at equal amounts: sulfate and glucuronide. A number of arguments suggest that MHPG sulfate and MHPG glucuronide respectively reflect central and peripheral norepinephrine metabolism. In this work, we have selectively estimated both MHPG conjugates in 24 h-urine samples of 36 severely depressed women in view to assess the extent and frequency of central or/and peripheral norepinephrine dysfunction. On the basis of MHPG sulfate and glucuronide values, we conclude that in the examined population (6 endogenous, 19 neurotic, 11 reactive depressions) about 80% of patients exhibited a central NE functional deficit, and many of them had also a diminished sympathetic activity. Clinical symptoms related to psychic factors (melancholia) or associated to sympathetic activity changes (anxiety, retardation) respectively alter sulfate or glucuronide MHPG excretion. These data altogether validate the concept of the independent origin of the two MHPG conjugated and show that their selective assay is able to provide a more satisfactory reflection of the psychobiological state in depressed patients than total MHPG determination.

Adult↗