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Biomedical subjects

D Ayalon

Publications and source records attributed to D Ayalon.

At least 73 records · Page 4Linked to original sources
PubMed1983

Effects of short-term treatment with gonadotropin-releasing hormone (GnRH) or ethinyl estradiol on the pituitary responsiveness to GnRH.

In 4 patients with hypothalamic amenorrhea, the pituitary responsiveness to an intravenous challenge of 20 micrograms synthetic gonadotropin-releasing hormone (GnRH) was evaluated before and following a 3-days treatment course with GnRH (100 micrograms/per day i.m.) or ethinyl estradiol, (100 micrograms/day orally). The amenorrheic patients all had normal or reduced levels of serum gonadotropins, no evidence of galactorrhea and no other endocrine abnormality. Following GnRH treatment basal luteinizing hormone levels as well as the luteinizing hormone and follicle-stimulating hormone responses to GnRH were markedly reduced when compared with responses to GnRH before the treatment. Responses to GnRH were significantly augmented after treatment with estrogens. In patients with previous treatment with GnRH the augmented estrogen-induced LH response to GnRH was abolished. These preliminary results support the pathophysiological concept that in amenorrheic patients with hypothalamic dysfunction long-term administration of GnRH does not result in an improvement but rather in a deterioration of pituitary gonadotropic function.

Adult↗
PubMed1983

Carcinoembryonic antigen in patients with colorectal cancer: correlation between stage of disease and antigen level.

Carcinoembryonic antigen (CEA) levels were measured by radio-immunoassay in the sera of 339 patients with various stages of colorectal cancer. Of 298 patients considered to be free of disease, 61 (20.5%) were found to have elevated CEA values of greater than 10 ng/ml. Of these patients, 36 had subsequent disease progression, 23 had only a transient rise in CEA and 2 showed a persistent increase with no clinical deterioration during the study period. Of 41 patients with known active disease, only 27 (65.9%) had elevated CEA values, most greater than 30 ng/ml, whereas the remaining 14 patients had CEA levels less than 10 ng/ml. Of a total of 77 patients with known active colorectal cancer throughout the whole study period, these 14 (18%) represent the number of false-negative CEA determinations. This relatively high rate of false-negative measurements should not obscure the fact that full accordance between CEA levels and clinical status as determined throughout 38 months of follow-up, occurred in 323 of the 339 patients.

Carcinoembryonic Antigen↗
PubMed1982

Effects of long-term treatment with bromocriptine on pituitary prolactinoma in a male.

Poor surgical results are obtained when operating on large prolactinomas, especially when an extrasellar growth is demonstrated. Several groups have reported tumor regression following bromocriptine treatment. A case report is presented of a young hyperprolactinemic man with a large pituitary adenoma with suprasellar extension, normal visual fields, decreased libido, impotence, hypogonadism and azoospermia. This man was treated with high doses of bromocriptine for a period of 5 months. A significant improvement of potency libido and sperm concentration associated with radiological evidence of a marked reduction of tumor size was noted following suppressive treatment with this ergot alkaloid.

Adult↗
PubMed1982

Hormonal profile during termination of midtrimester pregnancy by extraovular instillation of saline: plasma levels of prostaglandins, progesterone and human chorionic gonadotropin.

Midtrimester abortion was initiated for psychosocial reasons in 5 patients, and premature delivery in 2 patients with intrauterine fetal death using a new method for termination of pregnancy--the instillation of normal saline through the cervical canal into the extraovular space. Blood levels of 15-keto-13,14 dihydro-prostaglandin F2 alpha (PGF2 alpha-M), progesterone (P) and Human Chorionic Gonadotropin (HCG) were determined from the start of the procedure up to the expulsion of the fetus at frequent intervals in the peripheral circulation of these patients, by highly sensitive and specific RIA procedures. Following saline instillation and initiation of contractions, the concentration of PGF2 alpha-M increased significantly, reaching peak values either shortly before or at the time of delivery. This rise was associated with a significant decrease of P levels. Levels of HCG were variable. The possible significance of these results is discussed.

Abortion, Therapeutic↗
PubMed1982

In vitro effects of cannabinoids on follicular function in the rat.

delta 1-Tetrahydrocannabinol (delta 1-TCH), the major psychoactive constituent of marihuana, was found to suppress the preovulatory surge of gonadotropins and thereby to prevent ovulation in rats, rabbits and rhesus monkeys. These studies suggested that the drug acts primarily on the hypothalamus to suppress luteinizing hormone releasing hormone (LHRH) secretion. The aim of the present study was to examine the direct effect of delta 1-THC, the psychoactive constituent of marihuana and cannabidiol (CBD), one of its nonpsychoactive constituents, on preovulatory rat follicles in vitro. Both cannabinoids inhibited follicular steroidogenesis in a dose-dependent manner. Basal accumulation of progesterone (P), testosterone (T) and estradiol-17 beta (E2) was reduced up to 60% by the highest doses examined (100-200 microM). The luteinizing hormone (LH)-stimulated increase in P and T was inhibited by 75-88% by the highest doses of both cannabinoids (50-200 microM), while E2, accumulation was inhibited by only 40%. It appears that the inhibitory action of cannabinoids is exerted beyond LH binding and activation of adenylate cyclase and prior to pregnenolone formation in the gonadal steroidogenic pathway. In addition to this anti-steroidogenic effect, both cannabinoids induced resumption of meiosis in follicle-enclosed oocytes cultured in hormone-free medium; 200 microM delta 1-THC resulted in 80% maturation and CBD in 75%. It seems that the action of cannabinoids on rat follicles in vitro is unrelated to their psychotropic activity.

Adenylyl Cyclases↗
PubMed1982

Paradoxical hypersecretion of growth hormone in patients with endometrial atypical hyperplasia and carcinoma. Effect of hysterectomy.

Paradoxical hypersecretion of human growth hormone (HGH) followed a glucose load in patients with endometrial cancer and atypical hyperplasia of the endometrium. All patients had normal fasting plasma glucose and serum HGH concentration with a normal glucose tolerance curve. Their urinary estrogen concentrations were within the normal postmenopausal range. 6 months after abdominal total hysterectomy and bilateral oophorectomy, the glucose load was repeated. Following surgery all patients showed a normal suppression of HGH secretion during the hyperglycemic period. These findings suggest the existence of a HGH-releasing factor in the neoplastic and preneoplastic endometrial tissue. This factor might be related to the abnormal HGH responses observed.

Aged↗
PubMed1981

Failure of naloxone to antagonize metoclopramide induced prolactin rise.

Seven subjects aged 21--54 years were investigated. Serum PRL and DBH were estimated before and at 30, 60, 90 and 120 min after the administration of 20 mg clopropamide. The same parameters were estimated a second time when 0.4 mg naloxone was associated. PRL level increased and DBH decreased in all the patients in both investigations and no significant differences between the two occasions were detected. It is suggested that probably the two substances do not act on identical receptors.

Adult↗
PubMed1981

Effect of antihypertensive drugs on plasma renin activity and urinary excretion of prostaglandin E2.

Urinary prostaglandin (PGE2) and plasma renin activity (PRA) were determined in 3 groups of hypertensive patients before and following 5 days of treatment with different antihypertensive drugs. In all 3 groups studied a substantial decrease of blood pressure was noted following treatment. However, whereas administration of chlorthalidone and hydralazine initiated a significant rise of PGE2 and PRA excretion, treatment with propranolol was associated with a decrease of these two parameters. In view of these findings it seems therefore as if renal production of PGE2 (at least with regard to propranolol, a beta-blocking agent), is not related to the hypotensive effect of the drug.

Antihypertensive Agents↗
PubMed1981

Dissociation of thyrotropin and prolactin responsiveness to thyrotropin releasing hormone stimulation in L-dopa treated parkinsonian patients.

The hPRL, hTSH and T3 response to thyrotropin releasing hormone (TRH) stimulation (200 microgram i.v.) were studied in 8 parkinsonian patients under chronic L-dopa-carbidopa therapy. In 6 out of the 8 patients studied, treatment was stopped for a period of 2 weeks and the TRH stimulation test was repeated under similar experimental conditions. In the L-dopa-carbidopa treated patients basal hTSH levels and the hTSH response to TRH were significantly suppressed. By contrast, in the 6 patients 2 weeks after cessation of treatment, although basal hTSH levels were still suppressed, a normal hTSH response to TRH was observed. Neither the basal T3 and T4 concentrations, nor the T3 response to TRH were affected by the L-dopa-carbidopa treatment. In addition, basal hPRL levels as well as the hPRL: response to TRH were within the normal range in the two groups of patients studied. Our study provides further support for a dopaminergic inhibitory action on the hypothalamo-hypophyseal-thyroidal axis (HHTA). The inhibition of basal hTSH secretion and th hTSH response to TRH by L-dopa, suggest that the blocking action of dopamine is exerted at the hypothalamic as well as at the pituitary level. In our hands, chronic administration of L-dopa did not affect either tonic hPRL secretion of the hPRL response to TRH. The dissociation or response to TRH under the same inhibitory action of dopaminergic stimulation can be interpreted as demonstrating a greater sensitivity of the pituitary thyrotrophs, than the prolactin secreting cells, to the blocking effect of dopamine.

Aged↗
PubMed1981

Urinary prostaglandin-E2 in chronic renal disease.

Renal excretion of prostaglandin-E2 was measured by radioimmunoassay in patients with chronic renal diseases. Significantly elevated urinary prostaglandin-E2 amounts were found in patients with moderate renal insufficiency (creatinine clearances 20-59 ml/min). In mild and severe renal insufficiency, the urinary excretion of PGE2 was within the normal range. In the non-terminal stages of kidney failure, a definite correlation was found between the degree of renal impairment and the daily amounts of PGE2 in the urine. It is therefore concluded that in these stages of the disease the kidney produces elevated levels of PGE2 in an attempt to improve the decreased renal blood flow caused by the disease.

Chronic Disease↗
PubMed1979

The diagnostic value of pharmacodynamic tests in the hyperprolactinaemic syndrome.

Patterns of prolactin (PRL) secretion were studied in a group of 18 hyperprolactinaemic patients with galactorrhoea and menstrual disorders and in a control group of thirty-two women in the early puerperium (24 h after a normal delivery) following provocative (TRH and Chlorpromazine) and suppressive (L-Dopa and bromocriptine) stimuli. Five out of the eighteen hyperprolactinaemic patients tested had radiological evidence of a pituitary tumour, and two were treated surgically. The early puerperium patients with elevated basal PRL levels (100--700 ng/ml) demonstrated a significant PRL response to the various treatments. On the other hand, in the hyperprolactinaemic group, an impaired PRL response to TRH, Chlorpromazine and L-Dopa was noted in patients with basal PRL levels higher than 30 ng/ml, whereas bromocriptine suppressed effectively PRL levels in all the hyperprolactinaemic patients tested irrespective of their basal PRL concentrations. The ratio between the fall in PRL concentrations (as percent of the baseline) after L-Dopa administration (delta%L) versus the PRL decrement after bromocriptine treatment (delta%B) was calculated. In the early puerperium group with normal pituitary prolactin secreting cells this ratio was equal to 0.8. In the hyperprolactinaemic group, the five patients with radiological evidence of a pituitary tumour had significantly lower ratios ranging from 0.2 to 0.57. These data suggest that in terms of prolactin release, prolactin producing tumour cells are intrinsically refractory to hypo thalamic dopaminergic signals. The calculation of individual delta%L/delta%B ratios may serve, therefore, as a valuable indicator for early detection of autonomous pituitary prolactin secreting cells and for evaluation of the extent of the pituitary lesion.

Adult↗
PubMed1979

The cholyl glycine-1-14C breath test in various gastrointestinal disorders.

The cholyl glycine-1-14C breath test was evaluated in a variety of gastrointestinal disorders. 138 tests were performed in 106 patients. Methods of data expression were evaluated and the cumulative 8-hour value was used. In 27 control patients the upper limit of the normal was found to be 78. A good correlation was found between the peak values and the cumulative 8-hour values (r = 0.95, p less than 0.01). The reproducibility of the test was good (r = 0.985, p less than 0.05). Abnormal results were found in 12 out of 13 cases with resection of the ileum and 11 out of 14 cases with Crohn's disease of the distal small bowel. The test was normal in cases with diseases of the proximal small bowel (celiac, Whipple's and Chron's diseases). The test was also normal in patients with colitis. It was abnormal in some of the cases after cholecystectomy and in most cases with carcinoma of the pancreas. The breath test was useful in monitoring the results of treatment in bacterial overgrowth of the small bowel. False negative results were observed after antibiotic treatment. The method seems to be more sensitive than the Schilling test in diagnosing disease of the distal small bowel.

Adolescent↗
PubMed1979

Carcinoembryonic antigen in aqueous humor of patients with primary malignant choroidal melanoma.

Carcinoembryonic antigen levels were simultaneously determined in the aqueous humor and in the plasma of the 3 patients with primary choroidal malignant melanoma undergoing enucleation. An elevated carcinoembryonic antigen level was detected in the aqueous humor of 1 patient with no increase in plasma CEA level. In the other 2 patients no such elevation was found. A local increase of CEA levels produced by the tumor is likely to occur. Further studies are required of CEA levels of patients with primary malignant choroidal melanoma as an aid in diagnosis and treatment of this condition.

Aged↗