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Biomedical subjects

F Dray

Publications and source records attributed to F Dray.

At least 109 records · Page 6Linked to original sources
PubMed1980

[Bartter's syndrome: seven cases in siblings. Hypothesis of mild forms (author's transl)].

Three children with a Bartter's syndrome have been investigated: all of them had growth retardation, hypokalemia (less than 3 mmol/l), raised plasma renin activity and urinary prostaglandins (PGE2 and PGF2 alpha) and a decreased sensibility for angiotensin. In the siblings two children had also growth retardation with mild biological signs of Bartter's syndrome, and two children had normal growth slight hypokalemia raised RPA and urinary PH, and normal sensibility for angiotensin. These data suggest mild forms of this syndrome which could be the Bartter's syndrome diagnosed in adults after laxatives or diuretics absorption. Besides these data stated a negative correlation (p less than 0,01) between plasma K+ and RPA, negative correlation (p less than 0,01) between plasma K+ and urinary PGE2 and a positive correlation (p less than 0,01) between RPA and urinary PGE2. From these observations physiopathology of Bartter's syndrome is discussed.

Adolescent↗
PubMed1980

Failure of anti-inflammatory steroids to inhibit prostaglandin production by rat polymorphonuclear leucocytes.

1 Like rabbit polymorphonuclear (PMN) leucocytes, rat peritoneal glycogen-induced PMN leucocytes produced much greater amounts of prostaglandin when incubated with killed bacteria than in the absence of phagocytosable material. 2 Rat PMN leucocytes mainly prostaglandin E2 (PGE2), in amounts up to 17 ng/10(6) cells in 90 min incubation, some 25 times the amount produced by resting cells. 3 Indomethacin and meclofenamic acid inhibited prostaglandin production by resting and phagocytosing cells, the IC50 being of the order of 10(-6) to 10(-7) M for both drugs. 4 Hydrocortisone and dexamethasone at concentrations up to 10(-4) M did not cause significant dose-related inhibition of prostaglandin production in this system. 5 It is suggested that the phagocytosing PMN leucocyte is insensitive to the action of anti-inflammatory steroids with respect to prostaglandin production.

Animals↗
PubMed1980

Role of prostaglandins on growth hormone secretion: PGE2 a physiological stimulator.

PGE2 at 5 X 10(-8)M is a significant stimulator of GH release and seems to act at a step prior to the first signal for the inhibitory effect of SS. The amount of PGE2 released in the culture medium would appear, from what we have seen in our studies to date, to rule out any possibility that PGE2 is a GRF. However, the powerful role of PGE2 in the GH secretion process is evident. More detailed studies are needed, especially once a defined GRF becomes available. Investigations are currently in progress along these lines.

Animals↗
PubMed1979

[Bartter's syndrome: Recurrence in the course of a treatment inhibiting prostaglandin synthesis].

Two adults with Bartter's syndrome were treated first with propranolol and a potassium-sparing diuretic and then with indomethacin for 22 months. Inhibition of prostaglandin synthesis by indomethacin, confirmed by a fall in urinary excretion rate of prostaglandins E2 and F2 alpha, induced a marked decrease in plasma renin activity and aldosterone excretion rate and an increase in plasma potassium. While the first patient was well controlled by this therapy, the second had elevation of prostaglandin excretion after 8 months associated with a relapse of symptomatic hypokalemia. Reintroduction of propranolol in addition to indomethacin led to renormalization of plasma potassium. A therapeutic trial with another prostaglandin synthesis inhibitor, meclofenamate, also produced partial correction of hyperreninemia and hypokalemia but only for a short time. From these observations it is concluded that (1) inhibition of renal prostaglandins by indomethacin or meclofenamate represents an effective but transient therapy for Bartter's syndrome, and (2) while prostaglandin secretion may elude pharmacological inhibition, the addition of propranolol restores complete inhibition and the therapeutic benefits of the previous treatment.

Adult↗
PubMed1979

In vitro biosynthesis of juvenile hormone by the larval corpora allata of Manduca sexta: quantificationby radioimmunoassay.

An in vitro method has been developed for the investigation of the regulation of juvenile hormone biosynthesis by insect corpora allata. Glands were maintained in Marks medium 19AB and JH synthesis quantified by a modified radioimmunoassay for juvenile hormone I. The radioimmunoassay is specific for JH I and exhibits approximately 12.6% cross reactivity with JH II and no cross reactivity with JH III. The assay directly measures the JH present in culture medium and has a maximum sensitivity of 50 pg JH I equivalents. Corpora allata from day 5 last instar Manduca sexta larvae were used to define the kinetics parameters of the in vitro system, including a demonstration that small groups of right and left glands synthesize equivalent amounts of juvenile hormone. The juvenile hormones synthesized were identified as juvenile hormones I and II in a ratio of 1:4, respectively. Juvenile hormone III could not be excluded as a product of the corpora allata owing to the low cross reactivity of this homolog (1.7%) in the radioimmunoassay. Corpora allata from different developmental stages exhibited synthesis rates generally consistent with predicted activity based on in vivo hormone titers with the exception of day 5 of the last instar. The variation in gland activity relative to the control of juvenile hormone titer in vivo is discussed.

Aging↗
PubMed1979

Enkephalin-like products in embryonic chicken retina.

Using sensitive and highly specific radioimmunoassays, Met-enkephalin (Met-ENK) and Leu-enkephalin (Leu-ENK) have been shown to exist together in the retina of chicken embryo. After high performance liquid chromatography (HPLC), a fraction of the retinal extracts seems to be authentic Met-ENK. Following a G-50 filtration, the Met-ENK immunoreactivity has been found associated to three peaks, the lightest having an apparent molecular weight similar to that of the Met-ENK.

Animals↗
PubMed1979

Interrelationships between androgens and prostaglandins in the vas deferens of prepubertal rats.

Prostaglandin (PG) levels in the genital tract of male rats were measured at different ages. The vas deferens contained the highest amounts of both PGE2 and PGF2 alpha in young adult or prepubertal animals. PGE2 content increased considerably with age. PGE2 alpha was high in younger animals but decreased markedly at 35 days of age and remained low thereafter. PGE2 and PGF2 alpha were reduced following bilateral castration or hypophysectomy. Testosterone propionate (TP) prevented the postoperative fall in PG levels in a dose-dependent manner. Differences were noted in the relationship between changes in organ weight or PGE2 and pge2 alpha content, and the dose of TP injected, the operation, the time of treatment, and the PG studied.

Age Factors↗