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Biomedical subjects

D Powell

Publications and source records attributed to D Powell.

At least 127 records · Page 7Linked to original sources
PubMed1981

Substance P-like immunoreactivity in the nervous system of hydra.

Using immunocytochemistry we find substance P-like material in nerve cells of hydra. These nerve cells are situated in the ectoderm of the basal disk and tentacles. Radioimmunoassay of hydra extracts gives dilution curves parallel to that of synthetic substance P, from which it can be calculated that one animal contains at least 0.6 fmol substance P-like immunoreactivity. After chromatography on Biogel P-100, the substance P-like immunoreactivity elutes as a peak in the void volume and a peak at the position of synthetic substance P.

Animals↗
PubMed1981

Herpes zoster ophthalmicus: a medical review.

Patients with herpes zoster undergo extensive screening to detect underlying malignant disease which is compromising their immunity. In a retrospective survey of 1000 patients with herpes zoster ophthalmicus 12 patients had malignant disease which was known on presentation. No new cases were detected or discovered on follow-up. Three patients developed a disseminated rash, but none of these had an underlying malignant disease.

Adolescent↗
PubMed1981

Plasma prolactin and gonadotrophins in anorexia nervosa and amenorrhoea due to weight loss.

The role of prolactin in anorexia nervosa is controversial and both hyperprolactinaemia and normoprolactinaemia were reported in patients with anorexia nervosa. We have measured immunoreactive prolactin by radioimmunoassay in plasma samples from 14 consecutive patients with anorexia nervosa and found normoprolactinaemia in 13 patients and a borderline elevation of plasma prolactin in one patient. The mean plasma prolactin level in anorexia nervosa patients did not differ from an age-matched control group of patients with amenorrhoea due to simple weight loss. While we were unable to confirm reports on the common occurrence of hyperprolactinaemia in anorexia nervosa, the absence of hyperprolactinaemia suggests a different mechanism of amenorrhoea in patients with anorexia nervosa and due to simple dieting from that in idiopathic secondary amenorrhoea in which the frequency of hyperprolactinaemia is about 30%. The mean plasma follicle-stimulating hormone was abnormally low both in patients with anorexia nervosa and simple weight loss, while the mean plasma luteinizing hormone was depressed only in patients with anorexia nervosa. This difference is compatible with a more profound hypothalamic disorder in anorexia nervosa, which is not solely dependent on the weight loss, than in amenorrhoea due to simple dieting.

Adolescent↗
PubMed1980

Ultrastructure and steroid-binding studies in leiomyomatosis peritonealis disseminata.

Leiomyomatosis peritonealis disseminata (LPD) is characterized by the development of numerous leiomyomata throughout the peritoneal cavity which appear grossly malignant but histologically benign. The etiology of this disorder has been controversial. The tenth reported case of LPD is presented with ultrastructural evidence that these tumors arise from smooth muscle cells. The cytoplasmic estrogen and progesterone bindings by these tumors were ninefold and twofold greater than receptor concentrations in normal myometrium from the same patient. In addition to the steroid binding data, the strong association of this disorder with pregnancy or, as in this case, oral contraceptives suggests that the stimulus for neoplastic initiation and growth is hormonally related.

Adult↗
PubMed1980

Substance P in human cord blood and its degradation by placenta in vitro.

Plasma immunoreactive substance P (iSP) was measured by radioimmunoassay in 12 paired samples of maternal and cord blood, and in placental extracts. The mean plasma iSP concentration in the cord vein was 42.5 pg/ml, as compared to 77.3 pg/ml in the maternal peripheral vein plasma. There was no difference in the mean iSP concentration in the cord vein and artery. Although no iSP was detected in placental tissue, the placenta could not be excluded as the source of iSP in cord blood in view of the rapid degradation of synthetic SP by the placental in vitro.

Female↗
PubMed1980

Is the evidence for ectopic antidiuretic hormone watertight?

The clinical syndrome of inappropriate secretion of antidiuretic hormone (SIADH) associated with malignancy cannot be distinguished from a similar metabolic abnormality found in patients with non-malignant conditions. It is, nevertheless, widely accepted that SIADH associated with malignancy is due to the "ectopic" tumour production of arginine vasopressin (AVP). This view is challenged after scrutiny of available data. Since some malignant or non-malignant tissues may produce neurophysins, the presence of "ectopic" AVP in tumour tissue may be explained by active binding of AVP from the circulation by neurophysins. On the other hand, the absence of detectable AVP in tumour accompanied with SIADH suggests excess AVP secretion from the posterior pituitary or hyponatraemia due to other, as yet unidentified, antidiuretic factors. The concept of "ectopic" AVP may be false.

Arginine Vasopressin↗
PubMed1980

Clinical course and outcome of thirty-five pregnancies in infertile hyperprolactinemic women.

Thirty-five pregnancies occurred during a 21-month follow-up period in 68 women (51%) who presented with infertility and hyperprolactinemia. Bromocriptine was used in 33 patients, of whom 25 (76%) conceived. In the remaining 35 patients who did not receive bromocriptine, there were 10 pregnancies (28%). The presence or absence of menses and galactorrhea in infertile hyperprolactinemic women treated with bromocriptine did not affect significantly the pregnancy rate. No pituitary complication occurred during pregnancy in any hyperprolactinemic patient and there was no change in sellar x-ray appearance, even in two patients whom a plain skull x-ray showed a minor sellar abnormality. Of the 35 pregnancies, 25 occurred after bromocriptine therapy, 2 after thyroxine therapy, 2 after clomiphene therapy, and 6 without any treatment. Five pregnancies ended in first-trimester abortion, including four after bromocriptine treatment. It is concluded that hyperprolactinemia is a good prognostic factor in infertility and that the majority of patients become fertile after a course of bromocriptine. No congenital abnormalities were observed in the offspring of patients treated with bromocriptine, but the abortion rate was higher than average.

Abortion, Spontaneous↗
PubMed1980

Tumor hypercalcemia and "ectopic hyperparathyroidism".

1. All available evidence for and against the concept of ectopic hyperparathyroidism, including 307 case reports of tumor hypercalcemia, was collated. 2. Of 104 combined cases of tumors of the kidney, lung, liver, head, neck and esophagus, 91 (88%) were in men. 3. The parathyroid glands were examined in 170 of 307 cases and parathyroid hyperplasia or adenoma were described in 34 cases. This high frequency may reflect higher likelihood of reporting such association. 4. Analysis of the histological pattern of tumors associated with humoral hypercalcemia revealed a marked association with certain histological types in different organs, such as clear-cell carcinoma of the kidney and ovary, hepatocarcinoma and cholangiocarcinoma, pheochromocytoma, and squamous-cell carcinoma of the lung, head, neck, esophagus, and urogenital tract. This histological correlation is not compatible with the "random derepression" hypothesis. 5. The existence of tumor humoral hypercalcemia is well documented, as 61 of 74 operated patients sustained remission of hypercalcemia following tumor removal. 6. The evidence for ectopic PTH being produced by tumor is not well documented and is based on conflicting radioimmunoassay results. We have found no case in the literature which fulfilled unequivocally criteria of ectopic production of biologically active PTH. There has been a lack of studies of tumors for the presence of biologically active hypercalcemic factors because only relatively insensitive bioassays are available at present. More information is also required on microscopic bone changes in tumor hypercalcemia as x-ray studies alone are inadequate. 7. On the basis of the present evidence, causes and mechanisms of tumor hypercalcemia are likely to be multiple.

Adrenal Gland Neoplasms↗
PubMed1980

Substance P in ovarian carcinoid.

A high content of substance P (124 ng/g wet tissue) was demonstrated by radioimmunoassay in lymph node metastases in a patient with bilateral ovarian carcinoid tumours. The plasma substance P level was elevated but urinary 5-hydroxyindoleacetic acid (5-HIAA) was low. It is suggested that, in some carcinoid patients, an elevated plasma substance P level may help diagnosis and follow-up when urinary 5-HIAA is normal.

Adult↗