Biomedical subjects

O Richard

Publications and source records attributed to O Richard.

7 recordsLinked to original sources

PubMed1992

[Scaphoid bone].

The scaphoid is the most important carpal bone due to the frequency of its pathological involvement. Two points of radiological anatomy are stressed: the presence of the scaphoid tubercle whose projection gives rise to the scaphoid ring, the solid radio-capitatum ligament which bridges the scaphoid. Scaphoid fracture represents 70% of all carpal bone fractures and its presence must therefore be meticulously investigated on appropriate x-rays or on tomographies or CT scans, rather than by the classical repeat examination a fortnight later. CT provides good analysis of scaphoid fragments when consolidation is delayed (pseudarthrosis), allowing earlier and more justified indications for surgery. The wrist ligaments are poorly visualised by MRI at the present time; but it allows study of the cartilage and, most importantly, is a decisive examination when there is a doubt about bone vitality.

Arthrography↗

PubMed1992

[Intracranial venous sinus thrombosis in nephrotic syndrome].

A 3-year old child was admitted for a third relapse of nephrotic syndrome associated with intracranial hypertension related to dural sinus thrombosis (tomodensitometry). The treatment consisted in the association of low dose heparin and fresh frozen plasma. After a 3 year-follow-up, there was no neurologic sequelae, and the nephrotic syndrome was on complete remission. The radiologic features and the management of sinus thrombosis are discussed.

Brain↗

PubMed1992

[Blackfan-Diamond disease and malignancy: cause effect relationships?].

The authors report on a 24-year old patient with Blackfan-Diamond syndrome who developed a Hodgkin's disease. This patient became transfusion-dependent at the age of 10, after an initial period of corticosensitivity, and after failure of androgens. He developed hemochromatosis despite from parenteral chelation therapy. He died of infectious complications 4 months after the diagnosis of Hodgkin's lymphoma. A review of the literature shows an increased incidence of malignancies in Blackfan-Diamond syndrome (three cases of leukemia), and in similar disease (thalassemia and sickle cell disease), but not in other patients with hemosiderosis (primitive hemochromatosis, end-stage renal failure under dialysis). Etiopathogenic hypotheses are discussed.

Adult↗

PubMed1992

[Congenital tubulopathy with magnesium loss].

The authors report on a 1-year old girl who presented with transient hypotonia and polydipsia related to renal-concentrating defect. Renal magnesium and calcium wasting were noted when the subject was 3.5 years old, in association with distal tubular acidosis and nephrocalcinosis. Hypocalcemia and hypomagnesiemia persisted when the patient was 9.5 years old. About 50 cases of tubular defects with renal magnesium loss have been reported in the literature and show that magnesium loss may be either isolated or associated with potassium and/or calcium wasting. This hereditary defect may be due to an alteration in magnesium reabsorption in the thick ascending limb of the loop of Henle.

Acidosis, Renal Tubular↗

PubMed1991

Physical characterization and sequence identification of the ovary maturating parsin. A new neurohormone purified from the nervous corpora cardiaca of the African locust (Locusta migratoria migratorioides.

A novel neurohormone, which anticipates ovarian maturation, was recently purified using liquid chromatography from the African locust nervous corpora cardiaca. Both its function and production by the pars intercerebralis of Locusta migratoria lead to its name, the ovary maturating parsin (Lom OMP). In this study, the Lom OMP was physically and chemically characterized. Its multiply charged ion spectrum was interpreted as two peaks of quite equal size having molecular masses of 6923.4 Da (major peak) and 6907.3 Da. The Lom OMP presented no periodic secondary structure according to the far ultraviolet circular dichroism spectrum obtained. It is composed of 65 amino acids and included a high concentration of alanine but is devoid of cysteine, isoleucine, methionine, lysine and threonine. The amino acid sequence indicated only one microheterogeneity, observed at position 26, consisted in the replacement of serine by alanine. The calculated Mr of the two acidic isoforms (calculated pHi = 4.87) were found to be in agreement with mass spectrometry measurements. When compared to the sequence libraries, the Lom OMP, the first insect gonadotropic neurohormone, was revealed as an unique protein.

Amino Acid Sequence↗

PubMed1991

[Radiologic anatomy of the wrist].

Wrist imaging still relies first on plain X-Ray films, MRI allows excellent appreciation of the sculture of bones, ligaments, tendons and even nerves. C.T. is essentially useful in traumatology, while Wrist arthrography can be useful for detection of small ligament lesions.

Humans↗

PubMed1991

Inhibition of glucose metabolism by progesterone in adipocytes: role of protein synthesis.

Progesterone decreases [I-14C]glucose oxidation in isolated female rat adipocytes within 20 min of incubation. Because steroids regulate transcription mechanisms, the relationship between protein synthesis and glucose metabolism was studied in the presence of progesterone. Actinomycin D does not affect basal glucose oxidation or the progesterone effects on it; cycloheximide and puromycin decrease basal glucose oxidation, but only puromycin decreases the inhibitory progesterone effect. Although puromycin inhibits glucose transport, the common site of action of puromycin and progesterone does not seem to be glucose transport, which, as we showed previously, is not modified by the steroid. Incorporation of [3H]leucine into acid-precipitable proteins is decreased by puromycin and cycloheximide but not by actinomycin D or progesterone; moreover, the action of these inhibitors does not change in the presence of the steroid. As shown by electrophoresis (SDS-PAGE) and autoradiography, L-leucine is incorporated into adipocyte proteins as early as 20 min and progesterone increases this incorporation into five proteins. Leucine is a ketogenic amino acid that is also incorporated into lipids; progesterone depresses L-leucine incorporation into fatty acids by a glucose-dependent mechanism. These results suggest that the inhibitory effect of progesterone on glucose metabolism is related to an enhanced protein synthesis counterbalanced by decreased fatty acid synthesis.

Adipose Tissue↗