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Biomedical subjects

M A Morgan

Publications and source records attributed to M A Morgan.

At least 91 records · Page 5Linked to original sources
PubMed1994

Intravenous administration of cocaine stimulates gravid baboon myometrium in the last third of gestation.

OBJECTIVE: The hypothesis for this investigation was that intravenous cocaine results in a dose-dependent increase in myometrial activity of the unanesthetized, chronically instrumented gravid nonhuman primate. STUDY DESIGN: Seven chronically instrumented gravid baboons were individually caged in an environment of 14 hours of light and 10 hours of darkness. Maternal femoral artery and vein catheters and three pairs of myometrial electromyographic wires were surgically placed at 90 to 121 days' gestation (term 180 days). At least 5 days after surgery, bolus intravenous cocaine hydrochloride doses of 0.05, 0.1, 0.3, 0.5, and 1.0 mg/kg maternal body weight were administered according to various schedules. Myometrial activity was analyzed by quantifying the myometrial electromyographic envelope data as the power spectral density window of contraction activity and as the total area under the rectified electromyographic voltage signal (i.e., total electromyographic activity) before and during the experimental period. RESULTS: Myometrial contraction activity increased after the 0.3 mg/kg dose (p < 0.01), the 0.5 mg/kg dose (p < 0.005), and the 1.0 mg/kg dose (p = 0.07) compared with baseline. The total myometrial electromyographic activity also increased as the cocaine dose increased. CONCLUSION: Intravenous cocaine results in increased myometrial contractions in the gravid baboon during the latter third of pregnancy.

Animals↗
PubMed1994

Massive maternal obesity and perioperative cesarean morbidity.

OBJECTIVE: Our purpose was to determine the impact of massive maternal obesity (weight > 300 pounds) on perioperative morbidity among patients undergoing cesarean section. STUDY DESIGN: A case-control study was conducted on 43 massively obese pregnant women, identified by perinatal database search, who were delivered by cesarean section between Jan. 1, 1987, and Dec. 31, 1991, at Long Beach Memorial Women's Hospital. Forty-three randomly selected patients who underwent cesarean delivery served as the control group. Medical records were abstracted for perioperative variables and compared between groups. Student t test, chi 2, and Fisher's exact statistical analysis were used where appropriate. RESULTS: No significant differences were observed between groups for maternal age, parity, use of prophylactic antibiotics, length of recovery room stay, or wound dehiscence. The massively obese group was observed to be at significantly increased risk for emergency cesarean section (32.6% vs 9.3%, p = 0.02), prolonged delivery interval (25.6% vs 4.6%, p = 0.01), and total operative time (48.8% vs 9.3%, p < 0.0001), blood loss > 1000 ml (34.9% vs 9.3%, p = 0.009), multiple epidural placement failures (14.0% vs 0%, p = 0.02), postoperative endometritis (32.6% vs 4.9%, p = 0.002), and prolonged hospitalization (34.9% vs 2.3%, p = 0.0003). CONCLUSION: Massively obese pregnant women undergoing cesarean section are at significantly increased risk for perioperative morbidity.

Adolescent↗
PubMed1994

Palliative fetal surgery for diaphragmatic hernia.

Congenital diaphragmatic hernia is associated with a poor prognosis in spite of advances in antenatal detection and newborn care. Open fetal surgery has been suggested as a strategy for salvaging selected fetuses at high risk for pulmonary hypoplasia as a result of this lesion. We report a strategy for palliative fetal surgery with definitive repair postponed to the newborn period.

Adult↗
PubMed1994

Efficacy of intraperitoneal sodium carboxymethylcellulose in preventing postoperative adhesion formation.

Various regimens to reduce postoperative intraperitoneal adhesion formation have been tested; however, none has been consistently successful. The purpose of this study was to compare the efficacy of three compounds instilled into the peritoneal cavity--32% dextran 70, 0.9% normal saline and sodium carboxymethylcellulose--to no therapy on their ability to prevent postoperative adhesion formation in the New Zealand white rabbit. Bilateral posterior uterine horn incisions and cecal and transverse colon abrasions were performed during a two-phased study on each of 25 rabbits that were randomly assigned in a blind fashion into one of four study groups. Two weeks postoperatively, each rabbit underwent an autopsy to assess the magnitude of intraperitoneal adhesion formation. Adhesion scores were determined by counting the number of adhesions and assigning one or two points for each thin, filmy or dense, broad adhesion. As compared to no therapy, all three substances tested significantly reduced adhesion formation. Although 32% dextran 70 and 0.9% normal saline showed similar results, the degree of adhesion formation was reduced most significantly with sodium carboxymethylcellulose (P < .002) Sodium carboxymethylcellulose is effective in preventing postoperative adhesion formation in the New Zealand white rabbit.

Animals↗
PubMed1994

Abruptio placentae: perinatal outcome in normotensive and hypertensive patients.

OBJECTIVE: The objective of this study was to compare perinatal outcomes of hypertensive and normotensive women experiencing abruptio placentae. Our hypothesis is that hypertensive women have a less favorable perinatal outcome than do normotensive women. STUDY DESIGN: Women with the diagnosis of abruptio placentae delivered between July 1, 1988, and May 31, 1992, composed the study group (n = 226) in this case-control study. The incidence of abruptio placentae was 0.7% during this time. Those women with either multifetal gestations (n = 4) or delivery before 20 weeks' gestation (n = 2) were excluded from data analysis. The remaining 220 patients were divided according to their hypertensive (n = 29) or normotensive (n = 191) status. Maternal and neonatal medical records were reviewed and abstracted for demographic variables, antepartum complications, delivery route, abruptio placentae grade, neonatal gender, birth weight, Apgar score, cord pH, and perinatal mortality. These perinatal outcome variables were compared between the hypertensive and normotensive patient groups. RESULTS: Black women with abruptio placentae were significantly more likely to be hypertensive (p = 0.0078). Hypertensive women with abruptio placentae had the antepartum complication diabetes mellitus significantly more often than did normotensive women (p = 0.032). However, they were similar to normotensive women with regard to the frequency of positive urine drug screen and trauma. Hypertensive women were no more likely to be delivered before 32 or 37 weeks' gestation, have neonates weighing < 1500 or 2500 gm, or to be delivered by cesarean section. Abruptio placentae grades 2 and 3 occurred more often in hypertensive women (p = 0.053), as did significantly lower umbilical cord artery (p = 0.005) and venous (p = 0.003) pH values. Neonates from hypertensive women were no more likely to have low 5-minute Apgar scores or to die than those from normotensive women. CONCLUSION: Although hypertensive women experiencing abruptio placentae are more likely to have higher-grade abruptio placentae and lower umbilical cord pH values, the overall perinatal outcome was not significantly different from that of normotensive women experiencing abruptio placentae.

Abruptio Placentae↗
PubMed1993

Extinction of emotional learning: contribution of medial prefrontal cortex.

Stimuli associated with painful or otherwise unpleasant events acquire aversive emotional properties in animals and humans. Subsequent presentation of the stimulus alone (in the absence of the unpleasant event) leads to the eventual extinction of the aversive reaction. Although the neural basis of emotional learning has been studied extensively, considerably less is known about the neural basis of emotional extinction. In the present study, we show that the medial prefrontal cortex plays an important role in the regulation of fear extinction in rats, a finding that may help elucidate the mechanisms and, possibly, the treatment of disorders of uncontrolled fear, such as anxiety, phobic, panic and posttraumatic stress disorders in humans.

Animals↗
PubMed1993

Establishment of a hydrogen peroxide resistant variant of renal tubular epithelial cells: role of calcium-independent phospholipase A2 in cell damage.

Renal epithelial cells resistant to oxidant stress mediated by hydrogen peroxide have been isolated and characterized. African green monkey kidney epithelial cell line, BSC-1 cells, chronically exposed to 50 microM hydrogen peroxide for 15 passages exhibited increased catalase (1.5-fold) and glutathione peroxidase (2.4-fold) activity, as well as increased total cellular glutathione (1.6-fold). This was associated with the acquisition of resistance to hydrogen peroxide cytotoxicity, as judged by nuclear staining with ethidium homodimer and clonogenic survival assay. H2O2-adapted and wild-type BSC-1 cells were used to examine the role of elevated cytosolic calcium concentration and the activation of phospholipase A2 in the development of lethal cell injury. Despite dramatic differences in resistance to oxidative stress, both cell types showed similar kinetics of cytosolic calcium increase in response to challenge with hydrogen peroxide. In contrast to this, oxidant-induced release of arachidonic acid correlated with the resistance of both types of BSC-1 cells to oxidative stress. A mechanism-based inhibitor of calcium-independent phospholipase A2 (Hazen et al., J. Biol. Chem. 266, 7227, 1991) reduced oxidant-induced lethal cell injury, suggesting that this class of phospholipases contributes to damage of BSC-1 cells exposed to hydrogen peroxide. H2O2-adapted BSC-1 cells may represent a valuable tool to study adaptation to oxidative stress and various mechanisms of cell injury.

Animals↗
PubMed1993

Influence of labor and route of delivery on the frequency of respiratory morbidity in term neonates.

OBJECTIVES: The purpose of this study is to compare the frequency of respiratory morbidity (RDS-Type I, RDS-Type II and PFC) in term neonates relative to three different delivery modes (cesarean delivery without labor, cesarean in labor, vaginal delivery). METHODS: A case-control study was performed consisting of 692 maternal/neonate pairs at term gestation with either a documented mature lung profile at an obstetrical age > or = 37 weeks' gestation or a Dubowitz age > or = 38 weeks' gestation. RESULTS: Overall, the frequency of neonatal respiratory morbidity was 5.1%. Neonatal respiratory morbidity was observed in 23 (12.4%) of 186 cases when cesarean delivery was performed prior to the onset of labor; in 10 (5.6%) of 177 cases when the cesarean delivery was performed after labor had ensued; and in 2 (0.6%) of 329 cases when the fetus was delivered vaginally (P < 0.001). CONCLUSION: The frequency of respiratory morbidity in term neonates is influenced by labor and route of delivery, and it is highest when cesarean delivery is performed prior to the onset of labor.

Adult↗
PubMed1993

Effects of labetalol on uterine blood flow and cardiovascular hemodynamics in the hypertensive gravid baboon.

OBJECTIVE: The purpose of this study was to investigate the effects of labetalol on uterine blood flow and cardiovascular parameters in acutely instrumented, hypertensive gravid baboons. STUDY DESIGN: During the latter half of pregnancy six gravid baboons were acutely instrumented, with ultrasonic flow probes placed on ipsilateral, external iliac, and uterine arteries and a flow-directed pulmonary artery catheter in the pulmonary artery. After a stable arterial pressure baseline was obtained, norepinephrine was infused to increase mean arterial pressure by at least 20%. A 20-minute hypertensive steady state was obtained. Labetalol at 0.5 and 1.0 mg/kg was randomly infused, followed by a 2.0 mg/kg dose, each over 1 minute. A 20-minute recovery period followed every labetalol infusion, allowing the hypertensive steady state to reestablish. External iliac and uterine blood flow measurements were continuously recorded during the baseline and experimental trials. Mean arterial blood pressure, heart rate, pulmonary artery and capillary wedge pressure, central venous pressure, and cardiac output were obtained at 5, 10, and 15 minutes during each steady state and after each labetalol infusion. RESULTS: Labetalol at all dosages significantly reduced the mean arterial pressure and the systemic vascular resistance at 1.0 and 2.0 mg/kg. External iliac blood flow was not consistently significantly reduced; however, uterine blood flow was significantly reduced after the 1.0 and 2.0 mg/kg labetalol dosages (p < 0.05). Although uterine vascular resistance tended to increase after the 1.0 and 2.0 mg/kg doses, statistical significance was not achieved. CONCLUSION: Low-dose labetalol (0.5 mg/kg) significantly reduces the pharmacologic hypertensive gravid baboon's mean arterial blood pressure without adversely affecting uterine blood flow.

Animals↗
PubMed1992

Paranoid schizophrenia may be caused by dopamine hyperactivity of CA1 hippocampus.

Explicit consolidation of memory, or fixation of declarative belief, appears to be physically represented in changes of synaptic conductances of neurons in the parietal-temporal-occipital association cortex (PTO) of the mammalian forebrain. This fixation of belief in PTO is postulated to be critically dependent on a diffuse reinforcement signal via the inferior temporal cortex (ITC) ultimately caused by an increased output of the CA1 pyramidal cells of hippocampus. Analogous to the reinforcing mechanisms of other forebrain systems, this updating of the connection weights of the neural nets in PTO by the output of the critical neurons in CA1 is directly related to concentrations of dopamine (DA). We propose that the delusions (i.e., unreasonable beliefs) of paranoid schizophrenia are caused by a hyperactivity of the same DA-sensitive CA1 neurons that are responsible for the fixation of normal beliefs. The dramatic reduction in delusions with administration of neuroleptics, as DA D2 blockers, in schizophrenics may thus be explained by their acting to ameliorate the hyperactivity of these CA1 DA D2 receptors.

Antipsychotic Agents↗
PubMed1992

Efficacy of the fetal-pelvic index in nulliparous women at high risk for fetal-pelvic disproportion.

OBJECTIVE: The null hypothesis of this study is that the fetal-pelvic index will not determine the presence or absence of fetal-pelvic disproportion in 137 nulliparous women at high risk for fetal-pelvic disproportion. STUDY DESIGN: This study was undertaken by comparing the blinded fetal-pelvic index values and two other methods of identifying fetal-pelvic disproportion, ultrasonography-derived estimated fetal weight greater than or equal to 4000 gm and Mengert's index, to delivery outcomes in 137 nulliparous women at high risk for fetal-pelvic disproportion. RESULTS: After adequate labor trials, 55 of 73 patients who required operative intervention had a positive fetal-pelvic index (sensitivity = 75%). Seventeen of the 18 patients with a false-negative fetal-pelvic index value had persistent malpositions (15 occipitoposterior, 1 occipitotransverse, and 1 face presentation). Spontaneous vaginal deliveries occurred in 64 patients with 62 of them having a negative fetal-pelvic index (specificity 97%). The overall predictability of the fetal-pelvic index in this patient population was 85% and the positive predictability was 96%. However, neither ultrasonography-derived estimated fetal weight nor x-ray pelvimetry, when used alone, accurately detected the presence or absence of fetal-pelvic disproportion in nulliparous women at high risk for the condition. CONCLUSION: The fetal-pelvic index is efficacious in determining the presence or absence of fetal-pelvic disproportion in nulliparous women at high risk for the condition.

Birth Weight↗
PubMed1992

Perinatal outcome in pregnancy complicated by massive obesity.

OBJECTIVE: Our objective was to determine the impact of massive obesity during pregnancy, defined as maternal weight > 300 pounds, on perinatal outcome. STUDY DESIGN: A case-controlled study was conducted. Between Jan. 1, 1986, and Dec. 31, 1990, 111 pregnant women weighing > 300 pounds who were delivered at Long Beach Memorial Women's Hospital were identified with a perinatal data base search. A control group matched for maternal age and parity was selected, and perinatal variables were compared between groups. To control for potential confounding medical complications, massively obese patients with diabetes and/or chronic hypertension antedating the index pregnancy were excluded from the obese group, and the data were reanalyzed. The Student t test chi 2, and Fisher's exact statistical analysis were used where appropriate. RESULTS: Massively obese pregnant women are significantly more likely to have a multitude of adverse perinatal outcomes, including primary cesarean section (32.4% vs 14.3%, p = 0.002), macrosomia (30.2% vs 11.6%, p = 0.0001), intrauterine growth retardation (8.1% vs 0.9%, p = 0.03), and neonatal admission to the intensive care unit (15.6% vs 4.5%, p = 0.01). They also are significantly more likely to have chronic hypertension (27.0% vs 0.9%, p < 0.0001) and insulin-dependent diabetes mellitus (19.8% vs 2.7%, p = 0.0001). However, when those massively obese pregnant women with diabetes and/or hypertension antedating pregnancy are excluded from analysis, no statistically significant differences in perinatal outcome persisted. CONCLUSION: Massively obese pregnant women are at high risk for adverse perinatal outcome; however, this risk appears to be related to medical complications of obesity.

Adult↗
PubMed1992

Severity of asthma and perinatal outcome.

OBJECTIVE: Our objective was to determine the impact of asthma and its severity, as determined by medication requirements, on perinatal outcome. STUDY DESIGN: A case-controlled study was conducted. Among 30,940 live births at Long Beach Memorial Medical Center Women's Hospital, 183 deliveries occurred between Jan. 1, 1985, and Dec. 31, 1990, that were coded for the diagnosis of asthma. Eighty-one that required the chronic use of medications to control their disease were identified. Thirty-one patients were steroid dependent and 50 were non-steroid-medication dependent. A control group was randomly selected (excluding maternal transports), and selected perinatal variables were compared between groups. RESULTS: When compared with controls, steroid-dependent asthmatics were at significantly increased risk for gestational (1.5% vs 12.9%) and insulin-requiring diabetes (0% vs 9.7%). Preterm delivery and preterm premature ruptured membranes occurred significantly more often in both asthmatic groups. Overall cesarean section rate was significantly increased in the non-steroid-medication-dependent asthmatic group when compared with controls (56.0% vs 30.0%). Delivery by primary cesarean section was significantly more common in the steroid-dependent group (38.7% vs 19.2%), and a strong trend was noted among the non-steroid-medication-dependent patients (34.0% vs 19.2%). Cesarean delivery for fetal distress was also more common in these two asthmatic groups. Neonates born to both groups of asthmatic pregnant women were significantly more likely to be of birth weight < 2500 gm but did not have an increased frequency of intrauterine growth restriction. No significant differences in low 5-minute Apgar scores were found; however, neonates born to both steroid-dependent and non-steroid-medication-dependent asthmatics were significantly more likely to be admitted to the neonatal intensive care unit (39.0% and 22.0% vs 7.7%). Preterm delivery and low birth weight were complications observed significantly more often in the steroid-dependent asthma group when compared with the non-steroid-medication-dependent group (54.8% vs 14.0% and 45.2% vs 14.0%). CONCLUSIONS: Perinatal outcome is compromised in the pregnancy complicated by chronic medication-dependent asthma. The extent is variable and is associated with disease severity, as measured by medication requirements.

Asthma↗
PubMed1992

Septic arthritis and bacteremia due to Mycoplasma resistant to antimicrobial therapy in a patient with systemic lupus erythematosus.

We report a case of septic arthritis caused by Mycoplasma hominis in a patient with systemic lupus erythematosus. The infection started as monarthritis but spread to at least four joints despite apparently suitable therapy with various antimicrobial agents, including doxycycline, clindamycin, and ciprofloxacin; subsequent bacteremia was documented. Control was ultimately achieved with use of the experimental fluoroquinolone temafloxacin in combination with doxycycline administration, arthroscopic drainage of a persistently infected joint, several intravenous infusions of immunoglobulins (which led to increases in levels of antibodies specific to M. hominis), and discontinuation of corticosteroid therapy. Antimicrobial susceptibility testing of various mycoplasmal isolates showed the presence of the tetM gene, disparity between susceptibility to tetracycline and doxycycline, and increasing resistance to most antimicrobial agents used (including to fluoroquinolones before clinical use), although the patient ultimately had a favorable clinical response to treatment with combined modalities.

Adult↗
PubMed1992

Different patterns of myometrial activity and 24-h rhythms in myometrial contractility in the gravid baboon during the second half of pregnancy.

Two clearly distinct epochs of myometrial contractility were observed in 13 pregnant baboons when recorded either as intraamniotic pressure (IAP) or myometrial electromyogram (EMG). Contractures, epochs lasting longer than 3 min, were the characteristic form of myometrial activity throughout pregnancy. Contractures generated only small increases in IAP. Short-lived contractions, generating larger increases in IAP, were characteristic of labor and delivery. Power spectral analysis of IAP and myometrial EMG activity proved to be an effective means whereby periods when the myometrium was in the contractures or contractions mode could be easily distinguished. Concomitantly recorded maternal intraabdominal temperature showed significant 24-h variations. When myometrial activity switched from low-amplitude, long-lasting regular contractures of pregnancy to contractions, the switch always occurred around the onset of darkness. Five baboons went into spontaneous labor, 3 prematurely and 2 at term. In these animals the switch from contractures to contractions occurred for several nights before delivery. The recurrence and timing of the switch from contractures to contractions for several nights before delivery were similar to the pattern we and others have observed in the pregnant rhesus monkey. The presence of 24-h periodicity in the patterns of specific types of myometrial activity in another nonhuman primate lends support to the view that similar 24-h patterns of myometrial activity may occur in pregnant women.

Animals↗
PubMed1992

Department of pharmacy-initiated program for streamlining empirical antibiotic therapy.

The outcome of a department of pharmacy-initiated "streamlining" study designed to promote cost-conscious modifications of empirically selected antibiotic therapy is described. Two hundred forty-one evaluable adult patients started on restricted-use antibiotics at this university-affiliated community private teaching hospital were enrolled in a 9-week prospective streamlining study. Patients were alternately assigned to a Control (i.e., no pharmacist-initiated streamlining recommendations offered based on culture and susceptibility reports) or a Pharmacist Intervention group (i.e., pharmacist offers recommendations to streamline therapy). A statistically significant greater number of patients had their empiric antibiotic treatment courses modified to more appropriate antibiotic choices after receipt of culture and susceptibility reports among private prescribers in the Pharmacist Intervention group (83%) than in the Control group (38%) (p = .006). Additionally, pharmacists were overall successful in gaining prescriber acceptance for 64% of recommended changes of empiric antibiotic treatment courses before the receipt of culture and susceptibility reports (e.g., dose and/or frequency changes). There was no program effect observed with respect to improved physician response to microbiologic data that would allow streamlining empirical antibiotic choices in the Housestaff (i.e., medical or surgical residents), or infectious disease consultant prescriber groups. Projected overall annual cost savings that would be achieved as a result of continued efforts by pharmacists directed at streamlining empirical "restricted" antibiotic regimens is approximately +40,000.

Analysis of Variance↗