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M Williams

Publications and source records attributed to M Williams.

At least 595 records · Page 33Linked to original sources
PubMed1986

Effect of protein ingestion on urinary dopamine excretion. Evidence for the functional importance of renal decarboxylation of circulating 3,4-dihydroxyphenylalanine in man.

Since dietary protein increases urinary dopamine (DA) excretion in animals, this study was undertaken to assess the role of DA production in the acute changes in renal function following protein ingestion in man. Excretion of DA, sodium, potassium, water, solute, and creatinine were measured in six normal men in 30-min intervals over 5 h after oral ingestion of protein and/or carbidopa, an inhibitor of DA formation from 3,4-dihydroxyphenylalanine (DOPA). Overall, protein increased urinary DA 50% (P = 0.031) while carbidopa reduced it 70% (P less than 0.0001), although suppression of DA excretion by carbidopa was not uniform over the 5 h of observation. Carbidopa doubled the level of DOPA in venous plasma and greatly magnified the DOPA response to protein. Inhibition of decarboxylase activity reduced excretion of sodium, potassium, solute and water after protein ingestion. These results indicate that extraneuronal DOPA decarboxylation in kidney contributes to acute protein-induced changes in renal function in man and suggest a general role for the decarboxylation of circulating DOPA in the expression of dopaminergic effects on the kidney in vivo.

Adult↗
PubMed1986

Gastric antisecretory and pharmacologic properties of N,N-dimethyl-N'-(2-diisopropylaminoethyl)-N-(4,6-dimethyl-2-pyridyl)ur ea (L-634,366).

N,N-Dimethyl-N'-(2-diisopropylaminoethyl)-N-(4,6-dimethyl-2-pyridyl)urea (L-634,366) was selected from a series of pyridylurea compounds with antisecretory activity as a potential therapeutic agent for the treatment of ulcer disease. L-634,366 was an effective inhibitor of gastric secretion evoked by gastrin, histamine and 2-desoxy-D-glucose (2-DG) in conscious dogs. Orally, L-634,366 was slightly less potent than the reference H2 receptor blocker, cimetidine as an inhibitor of secretion evoked by histamine, but was equipotent as an inhibitor of secretion evoked by gastrin and 2-DG. In vitro L-634,366 was a weak antagonist of histamine (H2) receptor responses in the guinea-pig atria and rat uterus; in the atria the antagonism appeared to be noncompetitive. In the anesthetized dog, L-634,366 possessed weak anticholinergic activity as compared to atropine in reducing vagally mediated cardiovascular, antral motor responses and with regard to antagonizing the pressor response to the muscarinic stimulant, McN 343-A. The anticholinergic activity of L-634,366 was lower and more selective than that of pirenzepine or atropine in producing mydriasis in mice, in antagonizing acetylcholine induced bradycardia in guinea-pig atria, methacholine and acetylcholine elicited contractions in the guinea-pig ileum and QNB binding to muscarinic receptors. L-634,366, like carbenoxolone, increased incorporation of 3H-glucosamine in gastric mucous indicating an increase in synthesis or turnover of mucous. L-634,366 is a novel compound possessing a broad spectrum of antisecretory activity; in vitro studies suggested a weak noncompetitive inhibition of the histamine-H2 receptor in atria.

Animals↗
PubMed1986

Benzodiazepine interactions with central thyroid-releasing hormone binding sites: characterization and physiological significance.

Thyrotropin-releasing hormone (TRH) and several TRH analogs were examined in the [3H]-3-Me-His2-TRH ([3H]MeTRH) receptor-binding assay in rat amygdala, striatal and cortical membranes. The benzodiazepine, chlordiazepoxide, as reported in the literature was found to displace [3H]MeTRH with an IC50 value of 3.6 X 10(-7) M in amygdala membranes. Midazolam was, however, identified as being 6-fold more active than chlordiazepoxide with an IC50 value of 6.3 X 10(-8) M. The effect of these benzodiazepines on [3H]MeTRH binding did not appear to be related to their anxiolytic activity because the novel pyrazoloquinoline nonsedating anxiolytic, CGS 9896 was without effect on [3H]MeTRH binding at concentrations up to 1 X 10(-5) M. Chlordiazepoxide had similar activity in cortical membranes whereas midazolam was some 5 times less active in this preparation than in amygdala. Both compounds were weak displacers of [3H]MeTRH binding in striatal membranes, being at least two orders of magnitude less potent than in amygdala. In contrast TRH and its analogs, RX 77368 and DN-1417, were approximately 2 to 8 times more active in striatum than amygdala membranes. TRH and DN-1417 were less active in cortical membranes whereas RX 77368 was some three times more active than in striatum and amygdala. In three test procedures indicative of TRH agonist activity; thyroid-stimulating hormone release, reversal of pentobarbital sleeping time in mice and elevation of cerebellar cyclic GMP levels, the benzodiazepines were found to be devoid of activity, whereas TRH and related compounds produced their expected responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Amygdala↗
PubMed1986

Drug and radiation sensitivity measurements of successful primary monolayer culturing of human tumor cells using cell-adhesive matrix and supplemented medium.

The limitations of the agar suspension culture method for primary culturing of human tumor cells prompted development of a monolayer system optimized for cell adhesion and growth. This method grew 83% of fresh human tumor cell biopsy specimens, cultured and not contaminated, from a heterogeneous group of 396 tumors including lung cancer (93 of 114, 82%); melanoma (54 of 72, 75%); sarcoma (46 of 59, 78%); breast cancer (35 of 39, 90%); ovarian cancer (16 of 21, 76%); and a miscellaneous group consisting of gastrointestinal, genitourinary, mesothelioma, and unknown primaries (78 of 91, 86%). Cell growth was characterized morphologically with Papanicolaoustained coverslip cultures and cytogenetically with Giemsastained metaphase spreads. Morphological features such as nuclear pleomorphism, chromatin condensation, basophilic cytoplasm, and melanin pigmentation were routinely seen. Aneuploid metaphases were seen in 90% of evaluable cultures, with 15 of 28 showing 70% or more aneuploid metaphases. Colony-forming efficiency ranged between 0.01 and 1% of viable tumor cells, with a median efficiency of 0.2%. This culture system uses a low inoculum of 25,000 viable cells per well which permitted chemosensitivity testing of nine drugs at four doses in duplicate from 2.2 X 10(6) viable tumor cells and radiation sensitivity testing at five doses in quadruplicate from 0.6 X 10(6) cells. Cultures were analyzed for survival by computerized image analysis of crystal violet-stained cells. Drug sensitivity studies showed variability in sensitivity and in survival curve shape with exponential cell killing for cisplatin, Adriamycin, and etoposide, and shouldered survival curves for 5-fluorouracil frequently seen. Radiation sensitivity studies also showed variability in both sensitivity and survival curve shape. Many cultures showed exponential cell killing, although others had shouldered survival curves. This method for growing cells from primary human biopsy specimens is more efficient than the agar culture method, enables easier and better biological analysis of the actual cells grown, and permits improved characterization of drug and radiation survival curves.

Biopsy↗
PubMed1986

Evaluation of an enzyme immunoassay for estrogen receptors in human breast cancers.

An estrogen receptor enzyme immunoassay kit (ER-EIA) has been evaluated in 70 human breast carcinomas against a routine cytoplasmic [3H]estradiol binding assay (ERU). A linear correlation between the ER-EIA and the ERU was observed for binding values up to 400 fmol/mg of cytosol protein. Above this value, the ERU underestimates the concentration of receptor. The ERU gave a lower number of estrogen receptor-positive tumors (50 of 70) than did the ER-EIA assay (59 of 70). In the ERU-negative ER-EIA-positive tumors, receptor values as determined by the ER-EIA assay all fell below 50 fmol/mg of protein (mean, 19.9 +/- 4.2 fmol/mg of protein). Application of an exchange procedure which estimates the total steroid binding capacity of the cytosol gave positive results in 7 of 9 ERU-negative ER-EIA-positive tumors (mean, 16.9 +/- 2.95 fmol/mg of protein). Subdivision of the binding data according to the menopausal status of the patient indicates low receptor values in premenopausal women by each assay. A correlation between the ER-EIA assay and the histological grade of tumors was observed; Grade I well-differentiated tumors were all positive, while Grade II and III tumors were 86% and 75% positive, respectively. No correlation between the ER-EIA assay and tumor lymph node stage or tumor size was observed.

Adult↗
PubMed1986

Characterization of bovine surfactant for infants with respiratory distress syndrome.

Exogenous surfactant treatment of surfactant-deficient disease states is now under study in a number of centers, using a variety of surfactant preparations. We have chosen one preparation because of its current and potential clinical usefulness, and we have characterized it using selected tests and assays that we thought would be necessary (although not necessarily sufficient) to justify extended clinical use. We found its lipid composition to resemble that of other surfactants derived from lung mince. There is little variation among several batches with regard to lipid composition or surface tension-lowering capability. Morphologic heterogeneity occurs in individual samples of pelleted material studied by electron microscopy. Arterial oxygenation is improved when the material is administered to animals depleted of surfactant. A low molecular weight protein was identified that reacted with antibody that specifically binds nonserum surfactant proteins in a number of animal species (including human and cow). The characteristics of this surfactant preparation should be useful for comparison as newer and simpler products become available.

Animals↗
PubMed1985

Antagonism of L-5-hydroxytryptophan-induced head twitching in rats by lisuride: a mixed 5-hydroxytryptamine agonist-antagonist?

Lisuride antagonized L-5-hydroxytryptophan (5-HTP)-induced head twitches at doses lower than those sufficient to induce the serotonin (5-HT) syndrome. Among several other 5-HT agonists tested, only LSD and 1-(m-trifluoromethylphenyl)-piperazine (TFMPP) shared this paradoxical profile. Assessment of various dopamine (DA) agonists revealed a lack of correlation between DA-mediated stereotyped behavior (indicative of postsynaptic DA agonism) and blockade of 5-HTP-induced head twitches. Lisuride displaced specific ligand binding from putative S1a, S1b and S2 receptors at nanomolar concentrations, and other drugs that blocked 5-HTP-induced head twitches also displaced binding at S2 sites. It is proposed that lisuride may have agonist properties at S1a receptors mediating the 5-HT syndrome but antagonist properties at S2 receptors mediating 5-HTP-induced head twitching.

5-Hydroxytryptophan↗
PubMed1985

Alternate-day prednisone reduces morbidity and improves pulmonary function in cystic fibrosis.

A randomised, double-blind, placebo-controlled study examined the effects of alternate-day prednisone therapy on morbidity and progression of lung disease in cystic fibrosis (CF). At baseline the patients (aged 1-12 years) had mild to moderate lung disease, and the prednisone group did not differ significantly from the placebo group for any values measured. After 4 years, the prednisone-treated group had significant advantages over the placebo group for height, weight, vital capacity, forced expiratory volume in 1 s, peak flow rate, erythrocyte sedimentation rate, and serum IgG. The prednisone-treated group required 9 admissions to hospital for CF-related pulmonary disease compared with 35 for the placebo group. There were no steroid-induced side-effects. To rule out bias in case selection, 69 CF clinic patients comparable in age and clinical status but not included in the study were compared with the placebo group at 4 years; no significant differences between the groups were found.

Body Height↗
PubMed1985

Binding of [3H]cyclohexyladenosine to adenosine recognition sites in guinea pig ileal membranes: comparison with binding in brain membranes.

The stable adenosine agonist [3H]cyclohexyladenosine binds to membranes prepared from guinea pig myenteric plexus with high affinity (Kd = 1.8 nM) in a saturable, reversible manner. Binding pharmacology was consistent with the labelling of an A1 type adenosine receptor with the R-isomer of N6-phenylisopropyladenosine (PIA) being 11 times more potent than the S-diastereomer. Binding was similar to that observed in brain tissue being displaced by a number of xanthine adenosine antagonists. In terms of density of binding sites, however, there were approximately 9 times fewer higher affinity binding sites in ileal membranes than in the central nervous system.

Adenosine↗
PubMed1985

Endocrinological and clinical aspects of LHRH action (ICI 118630) in hormone dependent breast cancer.

The effect of an LHRH agonist, D-Ser (But)6Azgly10-LHRH (Zoladex, ICI 118630) on pituitary gland and ovarian function has been investigated in patients with advanced breast cancer. In both pre and postmenopausal women ICI 118630 produced a substantial rise in circulating concentrations of gonadotrophins within 2 h of the first injection. However, on continued exposure to the drug plasma LH and FSH levels decreased to below pre-treatment values (14-21 days). This was especially evident in postmenopausal women. In premenopausal patients plasma progesterone and estradiol levels were significantly reduced after 2 and 4-6 weeks of therapy respectively, reaching values observed in oophorectomized or postmenopausal patients. No substantial acute or long-term influence of the drug on these hormones was seen in postmenopausal women. Breast tumor remissions were recorded primarily in premenopausal patients with estrogen receptor positive tumors. No responses were seen in patients with estrogen receptor negative disease. Minimal side effects were recorded.

Adult↗
PubMed1985

Bioactive conformation of 1-arylpiperazines at central serotonin receptors.

A number of 1-arylpiperazines have been characterized as direct-acting serotonin agonists. Conformational parameters of this class that may affect receptor recognition and binding have been examined through the analysis of X-ray data and synthesis of rigid analogues. Radioligand binding studies indicate that 2,3,4,4a,5,6-hexahydro-9-(trifluoromethyl)-1H-pyrazino[1,2-a]quinoline, an arylpiperazine that mimics the X-ray conformation of the serotonin agonist 1-(6-chloropyrazin-2-yl)piperazine, exhibits high affinity for serotonin receptors, suggesting that the two rings of 1-arylpiperazines are relatively coplanar in the bioactive conformation.

Animals↗
PubMed1985

Mucormycosis after open fracture injury.

An 18-year-old woman (a former intravenous drug abuser) sustained open tibial plateau and shaft fractures, followed by cellulitis and a wound infection caused by a Rhizopus species, which is a fungus of the class Mucorales. The patient responded to surgical debridement and a prolonged course of amphotericin B. No lymphocyte abnormality or other host immune defect could be demonstrated in this patient.

Accidents, Traffic↗
PubMed1985

Kinetics of micronucleus expression in synchronized irradiated Chinese hamster ovary cells.

The kinetics of expression of radiation-induced micronuclei (MN) in synchronized Chinese hamster cells (CHO) was examined. The purpose of the study was to determine if the cell cycle distribution of a population significantly influences the levels of radiation induced MN, thereby obscuring the exact quantification of the radiation effect. Cells were synchronized by centrifugal elutriation, irradiated, and then different phases of the cell cycle were examined for: cell cycle progression, division probability, and temporal expression of MN. The results demonstrate that the time interval for maximal MN expression is long enough that the position of cells in the cell cycle and radiation induced division delays do not prevent the majority of cells from completing their first post-irradiation mitosis, therefore, expressing MN. By following the progression of synchronized cell populations by flow cytometry and also examining the time of division of individual cells for 24 hr after irradiation, we observed that the maximum number of cells from all phases of the cell cycle are in their first post-irradiation interphase at that time, thus explaining the MN results.

Animals↗
PubMed1985

Lack of thirst, osmoreceptor dysfunction, early puberty and abnormally aggressive behaviour in two boys.

Two unrelated boys (C.C. 13 years; J.W. 18 years) presenting with early puberty and episodes of aggressive behaviour were found to have hypernatraemia and hypodipsia. Plasma vasopressin (AVP) levels were inappropriately low in relation to plasma osmolality, but the patients did not have diabetes insipidus since 24 h urinary volumes were less than 1 litre and the maximal urinary osmolality was 1232 in C.C. and 950 in J.W. Plasma renin activity was elevated (greater than 2000 mg AI/1/h) although aldosterone concentrations were normal. Excretion of a water load (20 ml/kg) was delayed, but plasma renin and aldosterone fell with increased naturesis. An infusion of 0.85 mol/l saline produced a rise in AVP in C.C. but not in J.W. Insulin and hypotension resulted in the release of AVP in both boys suggesting a selective defect of osmoreceptor function. Hyperprolactinaemia and an exaggerated PRL response to TRH were also noted but no intracranial lesion was demonstrable on CT scan. These boys appear to have a hypothalamic syndrome with early puberty, hyperprolactinaemia, hypodipsia and osmoreceptor dysfunction which may be associated with aggressive behaviour.

Adolescent↗