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Biomedical subjects

J Patrick

Publications and source records attributed to J Patrick.

At least 91 records · Page 5Linked to original sources
PubMed1989

The effects of hypoxemia with progressive acidemia on fetal renal function in sheep.

In order to determine the effects of fetal hypoxemia on renal blood flow, glomerular filtration rate (GFR) and urethral and urachal urine output, we examined the effects of 3 h maternally-induced (9% O2, 3% CO2, 88% N2) fetal hypoxaemia on 10 chronically-instrumented fetal sheep between 127-135 days of gestation. Fetal arterial pH fell significantly during the second and third hours of hypoxia and this coincided with a significant increase in fetal arterial blood pressure (P less than 0.05). During the second hour of hypoxia, with mild acidaemia, fetal GFR decreased significantly and then, during the third hour, fetal GFR, urethral and total urine output were significantly elevated. During the 2-h recovery period urachal and total, but not urethral urine output, were significantly elevated (P less than 0.05). The data suggested that the increase in GFR and urine output measured during the third hour of hypoxia and the recovery period may reflect a pressure diuresis.

Animals↗
PubMed1989

Genes encoding neuronal nicotinic acetylcholine receptors.

Four genes (alpha 2, alpha 3, alpha 4, and beta 2), which encode proteins homologous to the Torpedo electric organ and vertebrate muscle nicotinic acetylcholine receptors, have been identified by cloning rat brain cDNAs. Injection of transcripts derived from these cDNAs into Xenopus laevis oocytes results in the formation of three nicotinic acetylcholine receptors. Two of these receptors, alpha 3/beta 2 and alpha 4/beta 2, have the characteristics of ganglionic nicotinic receptors. The third (alpha 2/beta 2) exhibits a previously undescribed pharmacology and thus represents a novel subtype that may be expressed in the brain. The wide distribution of alpha 2, alpha 3, alpha 4, and beta 2 transcripts in the brain indicates that neuronal nicotinic acetylcholine receptors are a major neurotransmitter receptor system.

Animals↗
PubMed1989

The physiological basis for fetal assessment.

Remarkable progress has been made during the last 15 years in understanding mechanisms that occur in the fetus as a response to hypoxia. Human experiments have defined the normal patterns and responses of the fetus to changes in the maternal environment. Considerable data exist regarding patterns of fetal breathing and body movements and of the FHR during midpregnancy in humans. Unfortunately, very little data exist from animal experiments during midpregnancy to confirm the usefulness of indices of fetal activity and blood flow during this important time in gestation. At the present time, it is sensible to conclude that a scientific basis exists for the application of fetal testing methods such as the biophysical profile, NST, and arterial wave-form velocities during the last 10 weeks of human pregnancy. However, it is important to recognize that the scientific basis for the use of such tests does not exist from animal experiments during the important period of 0.5 to 0.75 of gestation. As a result, clinicians need to be cautious regarding the interpretation of measurements made between 20 and 30 weeks' gestation. At present, fetal tests are based on observation of normal fetal behavior. The methods are time-consuming, labor-intensive, and subject to error because of the periodicities in fetal activity. The purpose of this symposium is to consider whether measurement of fetal responses to sound and vibration might be a more effective method of assessing fetal health. It is to be hoped that such new methods will be vigorously investigated before introduction into clinical practice.

Animals↗
PubMed1989

Psychiatrists choosing psychoanalytic training at mid-career.

At one institute 48 percent of physician candidates doing class-work are over 40. This percentage has increased over the past decade, perhaps reflecting new economic constraints and the increased proportion of women candidates. A review of the first training analysis, Freud's, and conversations with some present day candidates indicate that choosing training at mid-career can address specific adult developmental issues, including the "race against time," needs for increased structuring of family life and of creative work and shifts from physical to intellectual play and from being a mentee to mentorship.

Adult↗
PubMed1989

Activity of alcohol dehydrogenase and aldehyde dehydrogenase in maternal liver, fetal liver and placenta of the near-term pregnant ewe.

The activity of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) was determined in the near-term pregnant ewe. There was little ADH activity in fetal liver (4.4%) and placenta (0.2%) compared with maternal liver. Low KM (microM acetaldehyde) ALDH activity was similar in the three tissues. High KM (mM acetaldehyde) ALDH activity was less in fetal liver (57%) and placenta (16%) compared with maternal liver. These data and the pharmacokinetics of ethanol and its proximate metabolite, acetaldehyde, in the near-term pregnant ewe indicate that ethanol elimination from the maternal-fetal unit is regulated primarily by maternal hepatic ADH-catalyzed biotransformation of ethanol, and low KM ALDH activity in the fetal liver and placenta protects the fetus from exposure to ethanol-derived acetaldehyde, which is produced primarily in the maternal compartment.

Acetaldehyde↗
PubMed1988

Functional expression of a new pharmacological subtype of brain nicotinic acetylcholine receptor.

A new type of agonist-binding subunit of rat neuronal nicotinic acetylcholine receptors (nAChRs) was identified. Rat genomic DNA and complementary DNA encoding this subunit (alpha 2) were cloned and analyzed. Complementary DNA expression studies in Xenopus oocytes revealed that the injection of messenger RNAs (mRNAs) for alpha 2 and beta 2 (a neuronal nAChR subunit) led to the generation of a functional nAChR. In contrast to the other known neuronal nAChRs, the receptor produced by the injection of alpha 2 and beta 2 mRNAs was resistant to the alpha-neurotoxin Bgt3.1. In situ hybridization histochemistry showed that alpha 2 mRNA was expressed in a small number of regions, in contrast to the wide distribution of the other known agonist-binding subunits (alpha 3 and alpha 4) mRNAs. These results demonstrate that the alpha 2 subunit differs from other known agonist-binding alpha-subunits of nAChRs in its distribution in the brain and in its pharmacology.

Amino Acid Sequence↗
PubMed1988

Identification of children with cerebral palsy unable to maintain a normal nutritional state.

7 children aged 2-16 with severe cerebral palsy and growth failure were compared with children of the same weight in respect of their eating efficiency. Children with cerebral palsy took 2-12 times longer to chew and swallow a standard amount of puréed food and 1-15 times longer for solid food than did their weight-controls. A behaviour score of feeding characteristics was higher in children with cerebral palsy than in controls. Even long meal times do not compensate for the severity of these childrens' feeding impairment. The measurements of feeding efficiency provides the basis for early identification of children who cannot be adequately nourished without ancillary feeding by nasogastric tube or by enterostomy.

Adolescent↗
PubMed1988

Concordance of the MCMI and the MMPI in the diagnosis of three DSM-III Axis I disorders.

This study examines the diagnostic accuracy of the three clinical syndrome scales of the Millon Clinical Multiaxial Inventory for a representative psychiatric inpatient population (N = 103). These scales were designed to identify the following DSM-III Axis I disorders: Schizophrenia, major depression, and paranoid disorders. True-positive identification rate was found to be lower than that reported by Millon (1983) for psychotic disorders, despite (in the case of schizophrenia) high prevalence in the sample. A comparison with the MMPI revealed the latter to be more accurate than the MCMI in the identification of schizophrenia and major depression and less accurate in the identification of paranoid disorders. While the MCMI did identify successfully .50 of the paranoid disorders in the sample, the prevalence of these disorders was very low (.02). These findings argue strongly against the use of the MCMI as an alternative to the MMPI in inpatient psychiatric settings.

Adolescent↗
PubMed1988

Personality characteristics of work-ready workers' compensation clients.

Result of this investigation indicate that "work-ready" status constitutes a significant variable in the characterization of workers' compensation claimants. The mean MMPI profile obtained for work-ready claimants (N = 69) showed no scales elevated above 70. Previous compensation studies, which did not differentiate claimants on this basis, consistently reported an elevated (123) profile for this population. In addition to demonstrating the absence of significant psychological disturbance in this population on the MMPI, the present study also found that work-ready claimants do not differ from the general working population on a number of salient attitudinal variables (e.g., ambition, willingness to accept challenges, etc.).

Adult↗
PubMed1988

The DNA gyrase inhibitors, nalidixic acid and oxolinic acid, prevent iron-mediated repression of catechol siderophore synthesis in Azotobacter vinelandii.

Low concentrations of nalidixic acid and oxolinic acid that were just inhibitory to Azotobacter vinelandii growth promoted the production of the catechol siderophores azotochelin and aminochelin, in the presence of normally repressive concentrations of Fe3+. There was a limited effect on the pyoverdin siderophore, azotobactin, where low concentrations of Fe3+ were rendered less repressive, but the repression by higher concentrations of Fe3+ was normal. These drugs did not induce high-molecular-mass iron-repressible outer-membrane proteins and similar effects on the regulation of catechol siderophore synthesis were not produced by novobiocin, coumermycin, or ethidium bromide. The timing of nalidixic acid and Fe3+ addition to iron-limited cells was critical. Nalidixic acid had to be added before iron-repression of catechol siderophore synthesis and before the onset of iron-sufficient growth. Continued production of the catechol siderophores, however, was not due to interference with normal iron uptake. These data indicated that nalidixic acid prevented normal iron-repression of catechol siderophore synthesis but could not reverse iron repression once it had occurred. The possible roles of DNA gyrase activity in the regulation of catechol siderophore synthesis is discussed.

Azotobacter↗
PubMed1988

Fetal heart rate and activity patterns in growth-retarded fetuses: changes after vibratory acoustic stimulation.

Seventeen pregnant women who subsequently were delivered of infants with birth weights less than the third percentile were studied for examination of fetal heart rate and fetal activity patterns before and after a 5-second external vibratory acoustic stimulation. None of the fetuses was acidotic at birth. A reduced time was noted during which accelerations in heart rate occurred (50% less) and long-term fetal heart rate variability (25% less) in small for gestational age fetuses compared with age-matched, normally grown fetuses. The incidence of gross fetal body movements was significantly lower (40% less) in small for gestational age fetuses than in those who were appropriate for gestational age. Fetal heart rate and fetal activity patterns after stimulation with the electronic artificial larynx in small for gestational age fetuses were similar to those of appropriate for gestational age fetuses.

Acoustic Stimulation↗
PubMed1988

Effects of multiple-dose maternal ethanol infusion on fetal cardiovascular and brain activity in lambs.

Ethanol (2 gm/kg of maternal body weight administered in four equal doses of 0.5 gm/kg over 5 hours) was infused intravenously into nine chronically prepared pregnant ewes between 124 and 137 days' gestation. The data demonstrated a dose-response relationship between fetal arterial ethanol concentrations and the incidence of fetal breathing movements. Suppression of normal fetal electrocortical activity occurred at a low ethanol concentration and returned to control values at a time of very high arterial ethanol concentrations. This experimental model of a binge drinking episode further supports the hypothesis that ethanol suppresses fetal breathing movements by a direct central mechanism rather than indirectly by alteration of electrocortical activity.

Animals↗
PubMed1988

Fetal heart rate and fetal activity patterns after vibratory acoustic stimulation at thirty to thirty-two weeks' gestational age.

Twenty pregnant women between 30 and 32 weeks' gestational age were studied to examine the effects of a 5-second external vibratory acoustic stimulus on the fetal heart rate, fetal heart rate variability, and fetal activity patterns. There was an immediate significant increase in the basal fetal heart rate for 10 minutes compared with controls. There was also a significant increase in the mean duration of fetal heart rate accelerations without any change in the number of fetal heart rate accelerations. There were no changes in long-term fetal heart rate variability, fetal breathing, and gross fetal body movements.

Acoustic Stimulation↗
PubMed1988

Primary structure and expression of beta 2: a novel subunit of neuronal nicotinic acetylcholine receptors.

A new subunit, beta 2, of the neuronal nicotinic receptor family has been identified. This subunit has the structural features of a non-agonist-binding subunit. We provide evidence that beta 2 can substitute for the muscle beta 1 subunit to form a functional nicotinic receptor in Xenopus oocytes. Expression studies performed in oocytes have demonstrated that three different neuronal nicotinic acetylcholine receptors can be formed by the pairwise injection of beta 2 mRNA and each of the neuronal alpha subunit mRNAs. The beta 2 gene is expressed in PC12 cells and in areas of the central nervous system where the alpha 2, alpha 3, and alpha 4 genes are expressed. These results lead us to propose that the nervous system expresses diverse forms of neuronal nicotinic acetylcholine receptors by combining beta 2 subunits with different agonist-binding alpha subunits.

Acetylcholine↗
PubMed1988

Umbilical and uterine artery blood flow velocities after vibratory acoustic stimulation.

Twelve healthy pregnant women between 37 and 41 weeks' gestational age were studied to determine the effects of external vibratory acoustic stimulation on the blood flow velocity waveform in the umbilical and uterine arteries. There was a significant decrease in umbilical peak-systolic/end-diastolic ratio during the first 5 minutes after stimulus after comparison with control ratios. Analysis of the frequency distribution of instantaneous fetal heart rate values during Doppler measurements suggested that the decrease in umbilical peak-systolic/end-diastolic ratio was due to fetal tachycardia rather than a change in the placental vascular resistance. The uterine artery peak-systolic/end-diastolic ratio was not altered after vibratory acoustic stimulation.

Acoustic Stimulation↗
PubMed1988

Fetal responses to vibratory acoustic stimulation: influence of basal heart rate.

Forty-three healthy pregnant women between 26 and 40 weeks' gestation were studied to determine the influence of prestimulation basal heart rate on the maximum amplitude of the first fetal heart rate acceleration after external vibratory acoustic stimulation. A significant negative correlation was found between the maximum amplitude of the first fetal heart rate acceleration and the prestimulation basal fetal heart rate from 30 weeks to term. In the presence of fetal tachycardia (basal fetal heart rate greater than 160 beats/min), more than 50% of fetal heart rate accelerations after stimulus were less than 15 beats/min amplitude. There was also a significant maturational process in the immediate fetal heart rate response to vibratory acoustic stimulation that occurred between 26 to 28 and 30 to 32 weeks characterized by a prolonged increase in basal fetal heart rate and an increase in the maximum amplitude of the first acceleration after stimulation.

Acoustic Stimulation↗