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Biomedical subjects

J C Morrison

Publications and source records attributed to J C Morrison.

At least 325 records · Page 18Linked to original sources
PubMed1982

The canine eye: pectinate ligaments and aqueous outflow resistance.

The contribution of the pectinate ligaments to total aqueous outflow resistance was studied in 30 excised canine eye pairs by means of constant-pressure aqueous perfusion. Incision of these ligaments over one and two quadrants of the angle circumference increased the facility of aqueous outflow significantly more than could be attributed to normal "washout" alone. Neither mechanical nor enzymatic disruption of angle glycosaminoglycans could fully account for this phenomenon. The pectinate ligaments may therefore contribute to the canine aqueous outflow barrier by compartmentalizing the glycosaminoglycans in the spaces of Fontana. In addition, these ligaments, analogous to iris processes in the human, prevent widening of the canine angle and hold the filtration structures in a relatively compressed state, a situation that can be reversed by ligament incision.

Animals↗
PubMed1982

Meperidine metabolism in the parturient.

A study of meperidine metabolism was undertaken in 21 normal parturients at term. Meperidine, 50 mg intravenously, was the sole analgesic agent used during the intrapartum period. Maternal and cord blood assessment for meperidine and normeperidine was done by gas chromatography-mass spectrophotometry. Most maternal sera showed a typical meperidine elimination curve. A secondary rise in maternal meperidine 30 to 180 minutes after injection was found in 4 patients. One patient showed a significant alteration in normeperidine appearance. These data add further validity to the hypothesis that the pregnant woman can metabolize meperidine by several pathways.

Adolescent↗
PubMed1981

Hexoprenaline pharmacokinetics in pregnant and nonpregnant sheep.

Hexoprenaline, a beta 2-sympathomimetic agent, is used to suppress uterine contractions in the treatment of premature labor. However, little is known regarding the potential of this drug to undergo placental transfer or whether the pregnant state alters any of the pharmacokinetic parameters. Using sheep as a model, intravenous doses of 14C-hexoprenaline were administered to pregnant and non-pregnant animals. Measurable levels of radioactivity did not appear in fetal blood samples. After intravenous bolus administration, blood concentrations in the ewe could be fitted by a triexponential curve characteristic of a three-compartment pharmacokinetic model. Following intravenous infusion, a biexponential curve described the decline in blood concentrations. Mean terminal half lives for total radioactivity ranged from 2.5 to 4.2 hours. The pregnant animals tended to exhibit smaller apparent volumes of distribution and lower values for total body clearance, normalized to body weight, compared to non-pregnant sheep.

Animals↗
PubMed1980

The use of medroxyprogesterone acetate for relief of climacteric symptoms.

Climacteric symptoms in the menopausal woman are perplexing to the physician. Recent literature concerning the relationship of estrogen to carcinogenesis has caused many women to discontinue this medication; thus, there is a need for an alternative therapy for the relief of these symptoms. The drug medroxyprogesterone acetate (Depo-Provera) was assessed in a double-blind, randomized, placebo-controlled study involving 48 subjects. Only one of the placebo-treated patients claimed any relief from climacteric symptoms while only two of the patients who received the study drug noted little or no relief (P < 0.0001). Relief from climacteric symptoms began at 4 to 7 days after entry into the study and extended for 8 to 20 weeks. The only side effects were withdrawal bleeding and a slight, transient weight gain. Depo-Provera appears to be a reliable substitute for estrogen in the treatment of climacteric symptoms. Further investigations with this medication seem indicated.

Adult↗
PubMed1980

Coenzyme A-synthesizing protein complex of Saccharomyces cerevisiae.

The coenzyme A-synthesizing protein complex (CoA-SPC) is a multienzyme complex of Saccharomyces cerevisiae (Bakers' yeast), which has a molecular weight in excess of 200,000 as determined by Sephadex G-200 column chromatography. This multienzyme complex, which is insoluble in the crude yeast cell lysate, has been purified 229-fold. A cellular component of the yeast cell lysate, referred to as t-Factor, with a molecular weight of 400-1000 and chloride ion are involved in the solubilization of CoA-SPC. The CoA-SPC requires L-cysteine, D-pantothenic acid and ATP as substrates. The terminal CoA-SPC-bound intermediate is dephospho-CoA, which is subsequently phosphorylated and released from the complex as CoA. The sequence of reactions for the synthesis of CoA by the CoA-SPC differs significantly from those previously proposed for other systems. It could be that the reaction sequence is unique for the yeast cell.

Adenosine Triphosphate↗
PubMed1980

Placental transfer of intravenous fluoride in the pregnant ewe.

Fluoride ion is produced with the biotransformation of two commonly used anesthetics, methoxyflurane and enflurane. Fluoride ion is added to prenatal vitamin preparations and water to prevent carious teeth. Very high levels of fluoride assailure. Previous studies of placental transfer of fluoride ion were conflicting. Our study in pregnant ewes revealed rapid transfer of the fluoride ion across the placenta with high fetal to maternal ratios as early as 1 minute.

Animals↗
PubMed1980

Alternate procedure for the preparation of the coenzyme A-synthesizing protein complex of Bakers' yeast.

The coenzymes A-synthesizing protein complex (CoA-SPC) of Bakers' yeast synthesizes coenzyme A in an in vitro system from the precursors ATP, D-pantothenic acid and L-cysteine. CoA-SPC has been produced on a small scale by freezing Bakers' yeast cells in a mixture of diethyl ether and solid CO2, followed by a thawing period, and subsequent removal of the diethyl ether by vacuum. The resulting yeast lysate was then stirred for 18 h in the presence of t-Factor to solubilize CoA-SPC. When a greater quantity of CoA-SPC was needed, the danger associated with the use of a large volume of diethyl ether was apparent. Therefore, the freezing step involving diethyl ether and solid CO2 has been replaced by a process of slowly drying fresh Bakers' yeast until approximately 34% of the initial weight of the yeast remained as dry solids. The yeast solids were ground to further disrupt the cell wall and membrane structure. The grinding step was followed by rehydration of the dry yeast solids with deionized H2O and stirring the rehydrated yeast for 18 h to solubilize CoA-SPC.

Coenzyme A↗
PubMed1980

Characteristics of the binding of streptococcal lipoteichoic acid to human oral epithelial cells.

Membrane receptors for lipoteichoic acid (LTA) may be involved in the adherence of streptococci to human pharyngeal epithelial cells. Since streptococcal binding to oral epithelial cells has been shown to be low at birth with a gradual increase to adult levels within three days, the characteristics of the binding of radiolabeled LTA to epithelial cells were investigated. LTA binding to epithelial cells from both infants and adults was time- and cell concentration-dependent. Binding was reversible in the presence of a 50-fold excess of unlabeled LTA. The number of LTA-binding sites in infant cells was only one-half that of adult cells; the amount of LTA bound increased to adult levels within three days of birth and paralleled an increase in the ability of these cells to bind streptococci. Thus, oral epithelial cells may possess specific binding sites for LTA, and a critical number or arrangement of LTA-binding sites may be required for the optimal binding of streptococci.

Adult↗
PubMed1980

Lecithin-sphingomyelin ratio and RDS in patients with diabetes mellitus: possible mechanisms.

Controversy exists concerning the positive correlation of maternal diabetes mellitus and the propensity for the progeny to develop respiratory distress syndrome (RDS). The increased incidence of RDS in these offspring seems to occur despite the various physical and biochemical assessments which indicate a mature lung profile. Recent data seem to incriminate insulin antagonism of normal fetal physiologic processes as the principal culprit. Strict control of maternal glucose metabolism in the pregnant diabetic may be essential in reducing RDS in the infant of a diabetic mother.

Amniotic Fluid↗
PubMed1980

Analgesic efficacy of ibuprofen for treatment of primary dysmenorrhea.

Fifty-five women with primary dysmenorrhea were enrolled in a study which each took ibuprofen (400 mg), propoxyphene hydrochloride (64 mg), or a placebo alternately in consecutive menstrual cycles for relief of pain. Fifty-one completed the study during three successive cycles in this triple-blind, crossover, randomized investigation. Ibuprofen was clearly superior to propoxyphene and the placebo in patient preference, degree of relief, and need for supplementary analgesics. In addition, a significantly greater number of patients were able to pursue their normal daily functions during the ibuprofen cycle. Propoxyphene was superior to the placebo but not to the same extent as ibuprofen. Only three side effects were reported during the study, two relative to propoxyphene and one recorded during a placebo cycle. These data show that ibuprofen is an effective agent when used for treatment of dysmenorrhea without organic etiology.

Adult↗
PubMed1980

Effect of corticosteroids and fetomaternal disorders on the L:S ratio.

Hydrocortisone or placebo was administered to 126 women at risk for premature delivery who had immature lecithin:sphingomyelin (L:S) ratios in order to induce early surfactant synthesis. In 70 subjects (37 steroid-treated patients, 33 controls), L:S ratio was determined a second time between 9 hours and 7 days after therapy had been initiated. The treatment group showed a significant increase in the L:S ratio when compared to those who received the placebo. Moreover, patients who had fetomaternal disorders that accelerated or delayed lecithin production were also found to have increased L:S ratios after treatment. Fewer newborns developed respiratory distress syndrome (RDS) in the treatment group than in the control group and those in the former category who were affected by RDS had a milder clinical course.

Adolescent↗
PubMed1980

The late postpartum eclampsia controversy.

The diagnosis of late postpartum eclampsia remains controversial. Six cases thought to represent eclampsia occurring 3 or more days post partum are reported, as is a review of the pertinent literature.

Adolescent↗
PubMed1980

Sinusoidal fetal heart rate pattern.

The etiology of sinusoidal fetal heart rate (FHR) patterns is diverse and consequently they ave been associated with poor as well as normal fetal outcome. Four patients who demonstrated sinusoidal FHR patterns are reported, and the factors associated with these patterns and their effect on fetal outcome are discussed. Three of the babies were delivered by emergency cesarean section and were markedly depressed at birth. Two of the infants died and the third required prolong hospitalization. The fourth baby was delivered vaginally and had a normal outcome. The possible pathophysiology is discussed and recommendations are made for the management of this FHR pattern.

Acidosis↗
PubMed1980

Placental transfer and other physiologic studies with intravenous butorphanol in the anesthetized pregnant ewe.

In clinical evaluation, butorphanol has been used in labor pain with analgesia and newborn outcome comparable to meperidine. Only limited placental transfer studies have been done in the human. The placental transfer and effect of intravenous butorphanol (2 mg) on avrious cardiovascular parameters were determined in anesthetized sheep. Serum butorphanol was determined by a specific radioimmunoassay. Butorphanol 2 mg intravenously did not affect the measured cardiovascular parameters in either ewe or fetus. Butorphanol could be demonstrated in the fetal circulation within one minute of administration and appeared to reach equilibrium in the maternal circulation rapidly and to remain in equilibrium thereafter. A biexponential decline of butorphanol was observed in the maternal serum with a terminal elimination half-life of 50 minutes. The data suggest butorphanol distribution in the pregment ewe can be conceptualized by the two compartment model, with the fetus as part of the peripheral compartment. These studies support the clinical finding from other studies that butorphanol appears to be a safe analgesic for use in labor pain.

Anesthesia↗
PubMed1980

Prophylactic transfusions in pregnant patients with sickle hemoglobinopathies: benefit versus risk.

Pregnancy in patients with sickle cell disease has been a significant threat to maternal survival and good reproductive outcome. In the past several years, statistics for both maternal and perinatal outcome have improved. There is controversy, however, as to whether this improvement has resulted from the use of maternal transfusions or the aggressive and intense medical management afforded these patients in recent years. This study details the reproductive experience of 80 pregnant patients with significant hemoglobinopathies, 75 of whom were treated with partial prophylactic exchange transfusions during gestation. Each of the 75 patients who completed the protocol received 2 transfusions using buffy coat-poor washed packed red cells. The results show that there was no maternal mortality and a significant improvement in maternal morbidity compared to previous studies. There was also a significant improvement in fetal salvage, with a perinatal mortality rate of 26 per 1000. In addition, there were fewer premature and low birth weight infants as compared to other studies in the literature. Although these results were favorable, only a randomized multicentered study in the future will detail advantages and disadvantages of such therapy in the gravid sickle cell patient compared to intensive medical treatment without transfusion.

Anemia, Sickle Cell↗