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Biomedical subjects

P J Moore

Publications and source records attributed to P J Moore.

At least 37 records · Page 2Linked to original sources
PubMed1997

Splenogonadal fusion with limb deficiency and micrognathia.

Splenogonadal fusion (SGF) is a rare abnormality with two known types. In the continuous type, the spleen is connected to the gonad, and there are often limb defects, micrognathia, or other congenital malformations such as ventricular septal defect, anal atresia, microgastria, spina bifida, craniosynostosis, thoracopagus, diaphragmatic hernia, hypoplastic lung and abnormal lung fissures, polymicrogyria, deficient coccyx, and bifid spine C6-T3. The discontinuous type is usually not associated with congenital defects, and the gonad that fused with an accessory spleen has no connection with the native spleen. The etiology of SGF is not known. Conceivably, a teratogenic insult occurring between 5 weeks' and 8 weeks' gestation could interfere with the normal development of the spleen, gonads, and limb buds. We describe a case of splenogonadal fusion in a stillborn black boy with associated micrognathia and limb deformities. Also, we review the possible teratogenic etiologies and embryonic basis of SGF.

Abnormalities, Drug-Induced↗
PubMed1996

Adolescents and the contraceptive pill: the impact of beliefs on intentions and use.

OBJECTIVES: To determine which beliefs about the contraceptive pill predict adolescent females' intentions to use the pill and their actual pill use, and to examine how intentions toward other birth control methods influence adolescents' intentions to use the pill and their eventual pill use. METHODS: Three hundred forty-five adolescents were interviewed about their beliefs regarding the consequences of using the pill and about their intentions to use the pill and other contraceptive methods. Follow-up interviews were conducted 1 year later, during which subjects reported their sexual activity and oral contraceptive use over the course of the year. RESULTS: Concerns about health and physical appearance differentiated subjects who intended to use the pill from those who did not, those who reported actually using the pill at all from those who did not, and those who did or did not use the pill consistently. The impact of beliefs differed between sexually active subjects and those who first had sex after the initial interview. Intentions to use withdrawal were negatively related to subjects' use of the pill (beta = -0.19, P < .05), although intentions to use condoms were unrelated to pill use. Intentions toward abortion were unrelated to either intentions to use the pill or eventual pill use. CONCLUSIONS: Female adolescents' beliefs about the contraceptive pill predicted their initial intentions to use the pill and their actual pill use over the course of a year. Adolescents may view withdrawal-although apparently not condoms-as an alternative to pill use. Abortion appears to be a backup to pill use rather than a substitute.

Abortion, Induced↗
PubMed1996

Social comparison and affiliation under threat: effects on recovery from major surgery.

This study extends stress and affiliation research by examining the effects of preoperative roommate assignments on the affiliation patterns, preoperative anxiety, and postoperative recovery of 84 male coronary-bypass patients. Patients were assigned preoperatively to a room alone or to a semiprivate room with a roommate who was either cardiac or noncardiac and either preoperative or postoperative. Patients assigned to a roommate who was postoperative rather than preoperative were less anxious, were more ambulatory postoperatively, and had shorter postoperative stays. Independently, patients were more ambulatory postoperatively and were discharged sooner if assigned to a roommate who was cardiac rather than noncardiac. No-roommate patients generally had the slowest recoveries. Affiliations reflecting cognitive clarity concerns, emotional comparison, and emotional support were examined. Theoretical implications for research involving social comparison and affiliation under threat are considered.

Adult↗
PubMed1996

No association of PROP taster status and paternal history of alcohol dependence.

Taste sensitivity to bitter substances, including ethanol, may play a moderating role both in the initiation of drinking and in the intensity and frequency of drinking once it is initiated. A study (Pelchat and Danowski, Physiol Behav 51:1261-1266, 1992) showed an association between the capacity to taste PROP (6-n-propylthiouracil), a bitter tasting compound, and a family history of alcoholism. The implication of that finding is that family-history-negative individuals may be protected from early initiation of drinking or heavy consumption of alcohol once drinking is initiated. The present study sought to replicate those findings by using direct interview methods (versus history methods) to obtain alcohol use and alcohol problem information from the parents of "at risk" individuals and by examining a larger number of subjects. A bimodal distribution of the ability to taste PROP was found, similar to that observed in the general population. No association was found between the ability to taste PROP and a paternal history of alcoholism, regardless of the taste threshold employed or after controlling for several potentially confounding variables. A lack of association with alcoholism risk was also observed for subjects' self-reports of reasons for drinking or not drinking alcohol based upon taste preference: high-risk and low-risk for alcoholism groups were not distinguished by either a stated preference for the taste of alcohol as a reason for drinking or a stated dislike for the taste of alcohol as a reason for limiting drinking. Thus, neither taste sensitivity for PROP nor the palatability of ethanol appear to influence the choice to drink among adolescent and young adult individuals at high risk for developing alcohol-related problems.

Adolescent↗
PubMed1996

Unilateral cooling in the region of locus coeruleus blocks the fall in respiratory output during hypoxia in anaesthetized neonatal sheep.

In nineteen alpha-chloralose-anaesthetized 3- to 8-day-old lambs, the effect of cooling focally in the region of the locus coeruleus on respiratory output, as measured from phrenic nerve activity, was examined during normoxia and isocapnic hypoxia, and during infusion of adenosine or saline. Eleven lambs showed a 'biphasic' respiratory response to hypoxia, with an initial increase in phrenic nerve activity (phase 1) being followed by a decline to prehypoxic levels (phase 2). Cooling to 26-34 degrees C unilaterally in the locus coeruleus reversed the fall in respiratory output. When the probe temperature was returned to body temperature (39 degrees C) respiratory output fell again to phase 2 levels. Cooling had no effect during normoxia. In these lambs, adenosine infusion (0.3 mg kg-1 min-1 intra-arterially) during normoxia also decreased respiratory output. During adenosine infusion, cooling again increased respiratory output. Saline infusion did not affect respiratory output during normoxia with or without cooling. The other lambs did not show a biphasic respiratory response, i.e. increased respiratory output was maintained during isocapnic hypoxia. In these lambs adenosine had no effect on respiratory output. Cooling/rewarming the probe did not affect respiratory output during normoxia or hypoxia, or during adenosine or saline infusion. These results show that focal cooling in the dorsal pons at the locus coeruleus removes the inhibition of respiratory output seen in the neonatal biphasic respiratory response to hypoxia, but does not affect breathing in normoxia. This suggests that an important component of the biphasic respiratory response is mediated by the activation of neurones inhibitory to respiratory output, and involves either axons of passage or cell bodies lying in the locus coeruleus. Furthermore, the inhibitory effects of adenosine on breathing in the neonate appear to be mediated via this site.

Animals↗
PubMed1995

Alpha 1- and alpha 2-adrenoreceptor actions of phentolamine and prazosin on breathing movements in fetal sheep in utero.

1. We studied the effects of systemic administration of the alpha 1- and alpha 2-adrenoreceptor antagonist phentolamine and the selective alpha 1-adrenoreceptor antagonist prazosin on fetal breathing movements (FBM) and electrocortical activity (ECoG) in fetal sheep. In one group of fetuses (group I; n = 7) the effects of phentolamine were measured during normoxia and hypoxia. In the second group of fetuses (group II; n = 8) the effects of either phentolamine, or combined phentolamine and prazosin, or prazosin alone, were measured during normoxia. 2. In group I fetuses, the incidence of FBM increased after phentolamine treatment. An increase in the incidence and mean episode duration of low-voltage ECoG (LV-ECoG) was also measured after phentolamine treatment. These effects of phentolamine persisted during hypoxia. 3. In group II fetuses a pronounced decrease in the incidence of FBM occurred after administration of prazosin following either phentolamine or saline pretreatment. These effects of prazosin on FBM were independent of an effect on ECoG activity. 4. We conclude that catecholamines have a stimulatory role on FBM mediated via an alpha 1-adrenoreceptor mechanism. Phentolamine leads to an increase in FBM by preferentially antagonizing presynaptic alpha 2-adrenoreceptors over postsynaptic alpha 1-adrenoreceptors. This influence of phentolamine on FBM may be secondary to its effect on ECoG. Promotion of LV-ECoG by catecholamines is mediated via an alpha 1-independent mechanism.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1995

Compound adrenal medullary tumor.

Compound tumors of the adrenal medulla, characterized by a mixture of pheochromocytoma and ganglioneuroma, are rare, only 12 cases having been reported in the literature. We present the case of a 66-year-old woman with a left-sided incidentally discovered adrenal mass that was subsequently shown to contain elements of pheochromocytoma and ganglioneuroma. The patient had no history of hypertension but did have a history of "idiopathic" edema (dependent edema). A review of the literature shows hormonal hypersecretion in approximately three fourths of the reported cases. Because of the preoperative hypertensive crises from the pheochromocytoma component of the tumor, contemporary management of incidentally discovered adrenal masses must include preoperative hormonal evaluations to exclude endocrine hyperfunction.

Adrenal Gland Neoplasms↗
PubMed1994

Carotid sinus nerve section and the increase in plasma cortisol during acute hypoxia in fetal sheep.

1. We studied the effects of acute isocapnic hypoxia on plasma concentrations of adrenocorticotrophic hormone (ACTH) and cortisol in sixteen sheep fetuses at 118-125 days of gestation (term is 147 days). Eight fetuses had their carotid sinus nerves cut (denervation); the remaining eight had these nerves left intact. 2. There were no differences in the plasma concentrations of ACTH or cortisol between intact and denervated fetuses during normoxia. 3. Whilst plasma cortisol increased in early (after 15 min) and late (after 45 min) hypoxia in intact fetuses, the rise in cortisol in denervated fetuses was delayed, increasing significantly only by late hypoxia. 4. In contrast, plasma ACTH concentrations were increased in early and late hypoxia in both intact and denervated fetuses. The rise was smaller in denervated fetuses, but was not significantly different from that in intact fetuses. 5. Our results indicate that, in the sheep fetus, carotid sinus nerve section delays the rise in plasma cortisol in response to acute hypoxia without affecting the ACTH response. Further work is needed to establish the mechanism underlying this effect of denervation.

Acute Disease↗
PubMed1994

Effect of carotid denervation on plasma vasopressin levels during acute hypoxia in the late-gestation sheep fetus.

1. We measured plasma concentrations of arginine vasopressin (AVP), arterial, venous and amniotic pressures, and carotid and femoral blood flows in fifteen chronically instrumented fetal sheep at 119-125 days of gestation. In eight of the fetuses the carotid sinus nerves were cut (denervated fetuses); the other seven remained intact and served as controls (intact fetuses). 2. In the intact fetuses during hypoxia there was an increase in plasma [AVP] and in perfusion (arterial-venous) pressure, a transient bradycardia, and an increase in carotid and a decrease in femoral blood flow. Whilst femoral vascular resistance (perfusion pressure/femoral blood flow) increased, there were no changes in carotid vascular resistance during hypoxia. 3. In the denervated fetuses no significant bradycardia, fall in femoral blood flow or increase in femoral vascular resistance was present soon after the onset of hypoxia but plasma AVP increased to similar concentrations to those observed in intact fetuses during hypoxia. 4. We conclude that carotid denervation does not affect plasma [AVP] during hypoxia in fetal sheep. This suggests that (1) AVP release during hypoxia is not mediated by a carotid chemoreflex and (2) AVP does not play an important role in these initial fetal cardiovascular responses. Furthermore, we previously reported that intact fetuses survive acute hypoxia better than denervated fetuses following phentolamine treatment, and we believe this to be due to the action of a non-alpha-adrenergic vasoconstrictor released in part via a carotid chemoreflex. The present results suggest that this vasoconstrictor is not AVP.

Acute Disease↗
PubMed1994

Expression of desiccation-induced and lipoxygenase genes during the transition from the maturation to the germination phases in soybean somatic embryos.

Transitions between developmental programs during plant embryogenesis are usually characterized by differential gene expression. Soybean (Glycine max (L.) Merr.) somatic embryos from embryogenic suspension cultures germinate poorly on a germination medium even after being grown on medium containing abscisic acid until developmental changes are induced by desiccation. The objectives of this study were to investigate: (i) the relationship between water loss and germination of somatic embryos, (ii) changes in desiccation-induced polypeptides, and (iii) the expression of maturation- and germination-associated genes during the transition from maturation to germination of soybean somatic embryos. The results revealed that partial drying of somatic embryos at 76% relative humidity for 96 h resulted in more than 90% germination. Germination frequency was correlated with the percent fresh weight loss of the somatic embryos. Polypeptides induced by desiccation were classified into three groups based on the tissues in which they were expressed and the inducing agents to which they responded. Desiccation-induced polypeptides decreased or became undetectable upon inhibition. The expression of a maturation-associated gene, Mat1, was induced in both cotyledons and hypocotyl/radicle tissues of somatic embryos after 72 h desiccation. The transcript for this gene increased in concert with water loss from the embryos. During maturation of somatic embryos, the expression of embryonic lipoxygenase genes was turned on. Desiccation alone did not directly induce expression of germination-associated lipoxygenase genes SC514 and LOXB2 in somatic embryos.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1994

The high jugular bulb in ear surgery: three case reports and a review of the literature.

Encounters with the jugular bulb in ear surgery are uncommon. This communication relates three cases where the author was confronted with the bulb in middle ear surgery--one in relation to the external auditory canal when raising a tympanomeatal flap and two in the hypotympanum when entering the middle ear. The anatomy of the jugular bulb is considered, particularly in regard to its quite variable placement within the temporal bone. The manner of clinical presentation of the high jugular bulb and previous cases in the literature where the jugular bulb has been discovered in juxtaposition to the surgical approach are discussed. Implications of surgical management are considered.

Adult↗
PubMed1993

Stress and affiliation: hospital roommate effects on preoperative anxiety and social interaction.

Fifty-three preoperative men were studied who were assigned to a hospital roommate who varied in terms of the similarity of the roommate's health problem and surgical status. The similarity of a roommate's particular type of health problem to that of the patient exerted little detectable influence. However, patients assigned to a preoperative roommate were more anxious compared with those assigned a postoperative or nonsurgical roommate. Affiliation was also significantly greater with fellow preoperative roommates compared with postoperative roommates. The possibility that the obtained roommate effects on anxiety are mediated directly by affiliation is explored. Additional mechanisms and theoretical implications for basic research involving social comparison, stress, and affiliation relationships are discussed. Practical considerations for hospital policy also are considered.

Adult↗
PubMed1993

Afferent and efferent components of the cardiovascular reflex responses to acute hypoxia in term fetal sheep.

1. We studied the effects of acute isocapnic hypoxia on arterial and central venous pressures, carotid and femoral blood flows and heart rate in intact and carotid denervated fetal sheep between 118 and 125 days gestation, after pre-treatment with either saline, atropine or phentolamine. Electrocortical activity (ECoG) and the incidence of fetal breathing movements (FBM) were also compared between intact and carotid denervated fetuses. 2. There were no significant differences between intact and denervated fetuses in any variable measured during normoxia. Soon after the onset of hypoxia a marked bradycardia occurred in intact, but not in denervated fetuses. Femoral blood flow and femoral vascular resistance (perfusion pressure/femoral blood flow) increased in intact, but not in denervated fetuses. Carotid blood flow increased in both groups of fetuses during hypoxia, but carotid vascular resistance did not change. During hypoxia, the incidence of FBM and low-voltage ECoG was similarly reduced in both groups of fetuses. 3. Atropine produced a rise in fetal heart rate during the control period in intact but not in denervated fetuses. At the onset of hypoxia atropine prevented the initial bradycardia seen in intact fetuses. In denervated fetuses a further increase in heart rate occurred throughout the hypoxia. 4. All denervated fetuses treated with phentolamine died during the hypoxic challenge, but nine out of fourteen intact fetuses treated with phentolamine survived. 5. In intact fetuses which survived hypoxia after treatment with phentolamine, the increase in arterial blood pressure was smaller and the increase in femoral resistance did not occur. In these fetuses a rise in heart rate occurred in hypoxia. Carotid vascular resistance decreased during hypoxia after administration of phentolamine. 6. Our results indicate that the initial cardiovascular responses of the late gestation sheep fetus to hypoxia are reflex, and that the carotid chemoreceptors provide the afferent limb of this reflex. The bradycardia is mediated through a muscarinic pathway, as it is blocked by atropine. The femoral vasoconstriction is mediated through an alpha-adrenergic mechanism, mediated both neurally by a carotid chemoreflex and via catecholamines released directly from the adrenal medulla. Both these components are blocked by phentolamine. 7. The differences in survival between intact and denervated fetuses during hypoxia after phentolamine suggest that the carotid chemoreflex response to hypoxia involves mechanisms in addition to vagal efferents to the heart and alpha-adrenergic actions at peripheral blood vessels.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗
PubMed1993

Polydeoxycholate in human and hamster feces: a major product of cholate metabolism.

Fecal bile acid excretion is one of the two major routes by which cholesterol is eliminated from the body, fecal cholesterol being the other. During their enterohepatic circulation, bile acids are secreted into the duodenum, pass down the jejunum and into the ileum where more than 95% is reabsorbed by the gut. Bile acids that escape reabsorption in the small intestine are metabolized by microorganisms in the large intestine. The major routes of metabolism are reported to be deconjugation, dehydroxylation, especially at the 7 alpha-hydroxy position, and dehydrogenation of the hydroxyl moieties. There are also some reports that saponifiable metabolites containing mostly deoxycholic acid form a major component of the bile acids found in human feces. We have identified a novel metabolite of cholic acid, 3 alpha-hydroxy polydeoxycholate, in both human and hamster feces that is the major constituent of these saponifiable metabolites. Furthermore, we have shown in hamsters that the animals that excreted more bile acid were excreting the additional bile acid as polydeoxycholate. As expected, there was a negative correlation between bile acid excretion in the feces and plasma cholesterol concentrations in these animals. We speculate that polydeoxycholate is formed in the lower gut of both humans and hamsters and that, by its formation, bile acid will be sequestered in an insoluble form, thus inhibiting its reabsorption by the gut. This process may help to reduce plasma cholesterol concentrations and coronary heart disease in humans.

Animals↗
PubMed1992

Electromyographic and affective responses of episodic tension-type headache patients and headache-free controls during stressful task performance.

Thirty-four subjects meeting diagnostic criteria for episodic tension-type headache and 42 who rarely experienced headaches participated in two laboratory sessions in which cephalic electromyographic (EMG) activity, electrodermal activity, heart rate, and finger temperature were recorded. Subjects performed relaxation, choice reaction time, psychomotor tracking, voluntary muscle contraction, and cold pressor tasks. Headache subjects showed significantly greater EMG activity than controls during baseline and stressful task performance. During relaxation, both groups reduced EMG activity from baseline levels, and there was no significant difference in EMG level between the groups during relaxation. Headache subjects reported higher levels of subjective anxiety, depression, anger, and stress than controls. Headache subjects also reported higher levels of pain than controls, and headache subjects reported greater pain during stressful task performance relative to baseline and recovery periods.

Adult↗
PubMed1992

The application of generalizability theory to surface electromyographic measurements during psychophysiological stress testing: how many measurements are needed?

Generalizability theory is an extension of classical reliability theory that allows multiple sources of measurement error in an experimental design to be investigated simultaneously. In the present study, generalizability theory was used to evaluate measurement error in psychophysiological test procedures used to differentiate tension headache patients from normal controls based upon measures of electromyographic (EMG) responding. Thirty-three subjects who met diagnostic criteria for tension-type headache and 40 normal control subjects who rarely or never experienced headache participated in two laboratory sessions. EMG activity of head and neck muscles was recorded while subjects performed baseline, relaxation, choice reaction time, psychomotor tracking, and cold pressor tasks. Variance components were computed for an experimental design having subjects nested within experimenters and crossed with sessions and replications. Generalizability coefficients were computed for combinations of various numbers of sessions and replications. The generalizability of EMG measures was highly variable, depending on the experimental conditions in force. The largest sources of measurement error were attributed to the unique responsiveness of individual subjects under a particular set of treatment conditions. For some stress tests currently in use, data from several testing sessions may need to be averaged in order to achieve acceptable levels of generalizability. Generalizability greater than 0.80 can be expected only rarely when data are collected during a single session. In the research setting, low generalizability may account for the failure of EMG-based stress tests to differentiate tension headache patients from controls during stressful task performance. In the clinical setting, the generalizability of information derived from "stress profiling" or muscle "scanning" techniques, which depend on results obtained during a single testing session, is doubtful.

Adult↗