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M J Cook

Publications and source records attributed to M J Cook.

At least 73 records · Page 4Linked to original sources
PubMed1987

Temporal changes in uterine activity and prostaglandin response to RU486 in rhesus macaques in late gestation.

Progesterone withdrawal as a mechanism of parturition in primates is controversial because maternal, fetal, and amniotic fluid progesterone concentrations do not decrease before parturition. We therefore studied the effects of RU486 on uterine activity and amniotic fluid prostaglandins in four rhesus macaques implanted with amniotic fluid and maternal vascular catheters and with fetal electrocardiogram and uterine electromyogram electrodes at 119 to 124 days' gestation (term = 168 days). Uterine electromyogram, intra-amniotic pressure (hourly contraction area, mm Hg.sec/hr), and fetal electrocardiogram were monitored continuously. After a stabilization period (6 to 9 days) RU486 was administered orally (20 mg/kg/day) at 1000 hours for 3 days. Uterine activity increased from basal levels (less than 4000 mm Hg.sec/hr) 8 hours after the first dose of RU486, reaching levels of 12,000 mm Hg.sec/hr. A sustained increase in uterine activity (13,000 to 30,000 mm Hg.sec/hr) was observed for 48 hours before cesarean section with little or no cervical effacement or dilatation. Increases in amniotic fluid prostaglandin F2 alpha, 6-keto-prostaglandin F1 alpha, 13,14-dihydro-15-keto-prostaglandin F2 alpha, and 11-deoxy-13,14-dihydro-15-keto-11 beta, 16 epsilon-cycloprostaglandin E2 occurred 40 hours after the onset of increased uterine activity. In contrast, amniotic fluid prostaglandins in the control animals delivering at term (n = 4) increased 24 to 48 hours before significant increases in uterine activity occurred. Control animals but not those given RU486 demonstrated a progressive nocturnal peak in uterine activity before delivery. Progesterone receptor blockade stimulates intense preterm uterine activity but not the orderly sequence of changes in prostaglandins and cervical status observed during normal parturition.

Amniotic Fluid↗
PubMed1985

Computerized financial systems in the ambulatory care marketplace.

In summary, there are literally hundreds of vendor financial system product offerings that combine a confusing array of application areas, hardware features, and data processing approaches to support the medical marketplace. Ambulatory health care managers will make better decisions regarding investments in computerized financial information systems by objectively comparing the many diverse features and functions of various systems, identifying the desirable hardware capabilities needed to effectively support the systems, and understanding the differences between data processing approaches.

Ambulatory Care Facilities↗
PubMed1983

Circadian patterns and dexamethasone-induced changes in uterine activity in pregnant rhesus monkeys.

Five monkeys with amniotic pressure catheters were placed in restraining chairs on days 127 to 131 of gestation (term = 167 days) for examination of circadian patterns in uterine activity. Uterine activity (total area under the contraction curve) was recorded continuously for 3- to 9-day intervals while the animals were exposed to a 16-hour:8-hour light:dark photoperiod. A ratio of hourly contraction area to mean hourly contraction area was established for each individual, and a circadian pattern was observed, with the occurrence of peak uterine activity between 2200 and 0200 hours (analysis of variance, P less than 0.01). An unrestrained animal equipped with a telemetry device and monitored for 23 days demonstrated a similar pattern. Four other catheterized, chair-restrained, pregnant monkeys were used to examine the effects of dexamethasone on uterine activity rhythms. After a 48-hour control period, dexamethasone (0.1 mg/hr) was infused via a maternal venous catheter for 48 hours. Fetal and maternal estrone and estradiol levels and total uterine activity were significantly reduced during dexamethasone infusion (P less than 0.05). In the 48 hours after dexamethasone infusion, mean uterine activity returned to preinfusion levels but the nocturnal peak remained ablated. Therefore, dexamethasone, alters the magnitude, as well as the circadian pattern, of uterine activity in association with reduced estrogen biosynthesis by the fetoplacental unit. Since the effect on uterine activity is biphasic, dexamethasone probably acts by more than one mechanism.

Animals↗
PubMed1982

Cell-surface discoidin in aggregating cells of Dictyostelium discoideum.

Both discoidin I and discoidin II have been detected on the surface of aggregating (10 h developmental stage) cells of Dictyostelium discoideum NC4 by radioiodination of the cell-surface followed by immunoprecipitation and sodium dodecyl sulphate/polyacrylamide-gel-electrophoretic analysis. Approx. 92% of cell-surface discoidin I and 72% of cell-surface discoidin II can be eluted with 0.5 M-galactose, showing that most of each endogenous lectin is not present as integral membrane protein but rather is bound to cell-surface discoidin receptors. Two-dimensional polyacrylamide-gel-electrophoretic analysis of discoidin I suggests that the native tetramer may be a hetero-multimer composed of both Ia and Ib subunits. Cell-surface discoidin I also contains both types of subunit, but it is not clear whether both subunits have corresponding cell-surface receptors.

Carrier Proteins↗
PubMed1980

Materno-fetal pharmacokinetics and fetal distribution of valproic acid in a pregnant rhesus monkey.

Chronic indwelling catheters in the maternal femoral artery and vein, fetal carotid artery and jugular vein, and amniotic cavity of a pregnant rhesus monkey permitted administration of sodium valproate (NaVPA) and collection of timed samples of maternal and fetal blood and amniotic fluid. After a single IV dose (50 mg/kg) to the mother, a rapid distribution phase (t1/2 alpha = 0.5 minute) was followed by a biphasic decline in concentration in maternal blood (t1/2 beta = 31 minutes, t1/2 gamma = 390 minutes). VPA appeared rapidly in fetal blood, reached a concentration slightly higher than in maternal blood by 15 minutes, and thereafter declined in parallel with the concentration in maternal blood. Terminal fetal/maternal ratios of blood concentration of VPA were about 1.3. Similar patterns of decline were observed after NaVPA was given IV to the fetus. A multicompartment first-order materno-fetal pharmacokinetic model is presented. Tissue distribution studies in the fetus showed that VPA concentration was highest in blood; moderate in heart, liver, spleen, kidney, and skeletal muscle; and low in brain.

Amniotic Fluid↗
PubMed1970

Practical examining. 1.

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Education, Nursing, Diploma Programs↗
PubMedDate not supplied

Three-dimensional fractal analysis of the white matter surface from magnetic resonance images of the human brain.

The convolutions of the cerebral cortex are difficult to describe and delineate. Our understanding of the development of the brain and its associated maldevelopment would be assisted by quantitative analysis of the cortex. Volumetric magnetic resonance (MR) imaging provides high-resolution anatomical data from which we can reconstruct the white matter as a three-dimensional object and extract its surface (the grey/white matter interface). Three-dimensional fractal analysis of this surface is a method of quantifying the surface complexity dependent upon the variation of the surface area under different scales of inspection. We estimate the fractal dimension of the white matter surface for each hemisphere and 10 coronal blocks of each hemisphere in 30 normal adult subjects. These values are tightly distributed and have been used to define a normal range of fractal dimensions. Abnormal fractal dimensions were found in 8/16 subjects with epilepsy and a gyral abnormality observed on routine MR imaging; and in 9/23 subjects with epilepsy and normal routine MR imaging. These analytical techniques offer additional information about the structure of the cortex in normal brains and about abnormalities of structure in subjects with suspected but unobserved structural abnormalities.

Adult↗