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Biomedical subjects

M Morris

Publications and source records attributed to M Morris.

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

A large family with subtelomeric translocation t(18;21)(q23;q22.1) and molecular breakpoint in the Down syndrome critical region.

We describe a 17-month-old infant with clinical features of Down syndrome and a normal karyotype by standard chromosomal analysis, her two uncles aged 28 and 30 years, respectively, with reduced intelligence and unusual appearance but not apparent Down syndrome, and a severely retarded 6-year-old girl with dysmorphy and epilepsy from the same family. Cytogenetic studies of patients and normal intervening relatives had been carried out at different institutions with normal results. Fluorescence in situ hybridization using whole chromosome painting and unique-copy probes (cosmids) and high-resolution banding revealed a familial subtelomeric translocation of chromosomes 18 and 21, resulting in partial trisomy 21 in the infant and her two uncles, and partial monosomy 21 in the 6-year-old girl. Cytogenetic breakpoints were located in bands 18q23 and 21q22.1, respectively. The molecular breakpoint on chromosome 21 was located between D21S211 (proximal) and D21S1283 (distal) and thus maps within the Down syndrome critical region.

Adult↗
PubMed1997

An outcomes management program in gynecologic oncology.

OBJECTIVE: To evaluate the effectiveness of an outcomes-management program designed to provide high-quality patient care, generate data for outcomes research, and decrease costs in a managed-care environment. METHODS: An outcomes-management program was launched in June 1994, based on the elimination of wasteful or ineffective therapies through the systematic development of practice guidelines and collaborative care paths, with concomitant definition of desired outcomes. Over 3 months, care paths were developed for our most common surgical procedures. A matched control outcomes study was undertaken for the most commonly performed gynecologic oncology procedure: total abdominal hysterectomy and oophorectomy with pelvic and para-aortic node sampling for endometrial cancer. Thirty consecutive women treated on the care path were compared with 29 matched controls accrued during the period of care-path planning and with 73 controls from the period preceding care-path planning. Patient satisfaction with care-path treatment was assessed by a survey sent 2 weeks after discharge. RESULTS: Median length of hospital stay decreased significantly, from 6 days before care-path planning to 4 days after care-path implementation (P < .001). Median laboratory costs decreased by 74% (P < .001), medication costs by 35% (P < .001), room costs by 29% (P < .001), and total hospital costs by 20% (P < .002). Incremental improvements were observed during care-path planning. There were no readmissions for complications in the care-path group. According to the survey results, patient satisfaction with care was very high among care-path patients. CONCLUSIONS: A physician-driven outcomes-management program in an academic setting permits the delivery of high-quality care and supports outcomes research while decreasing costs.

Cancer Care Facilities↗
PubMed1997

Single and repeated environmental stress: effect on plasma oxytocin, corticosterone, catecholamines, and behavior.

Rat studies were done to further characterize an environmental model of stress designated shaker stress (SS). Plasma oxytocin (OT), corticosterone (CS), norepinephrine (NE), and epinephrine (E) were measured before and after 5 or 30 min of SS applied one time or applied 10 times over a 2-week period. The major findings were partial adaptation of plasma E within 30 min of acute SS, adaptation of plasma CS baselines but not responses to chronic SS, and complete adaptation of plasma OT responses to chronic SS. Poststress behavior during chronic SS was affected in the following ways: freezing time habituated, defecation and rearings increased, and grooming and teeth chattering remained relatively constant. The results show that SS produces consistent patterns of hormonal and behavioral responses; some aspects of the patterns are similar to those elicited by other environmental stresses, whereas some aspects are unique to SS. We conclude that rats do not adapt to repeated SS but rather that most hormonal and behavioral defense mechanisms are renewable on a daily basis.

Animals↗
PubMed1997

Acanthoxin, a toxic phospholipase A2 from the venom of the common death adder (Acanthophis antarcticus).

This is the first report of a phospholipase A2 (PLA2) from the venom of the common death adder, Acanthophis antarcticus. Acanthoxin is a basic, monomeric PLA2 of mol. wt 13,000, consistent with the weight of neurotoxic PLA2s from other Australian elapids. However, preliminary ultracentrifugation experimentation has shown that it is able to undergo concentration-dependent aggregation to form dimers. It has a relatively high degree of enzymatic activity (23.93 +/- 1.18 mumoles of phospholipid hydrolysed/min/mg protein), but a low level of toxicity (3.2 mg/kg, s.c.). Acanthoxin is known to exist as two isoforms (A1 and A2), both of which show a high degree of homology with numerous elapid PLA2 neurotoxins, in particular pseudexin A from the red-bellied black snake (Pseudechis porphyriacus).

Amino Acid Sequence↗
PubMed1997

Sclerosing encapsulating peritonitis associated with continuous ambulatory peritoneal dialysis: surgical management.

Sclerosis of the peritoneum with encapsulation of the small intestine is one of the most serious complications of continuous ambulatory peritoneal dialysis (CAPD) and is associated with a high mortality rate. Its presence should be suspected in patients treated by CAPD who develop small bowel dysfunction with associated abdominal pain and progressive loss of ultrafiltration. In its severest form, it leads to complete high small intestinal obstruction and requirement for total parenteral nutrition. We report the successful surgical management of two young, severely emaciated patients who had this complication of CAPD. Each had entrapment of their bowel by a thick, fibrosed, and calcified membrane. Both were treated by surgically peeling the membrane away from the intestines.

Adolescent↗
PubMed1997

Baroreceptor regulation of salt intake.

Baroreceptor input plays a critical role in body fluid balance and the endocrine response to NaCl consumption [25]. Experiments were performed to characterize the alterations in salt intake that are seen after baroreceptor denervation. Using chronically baroreceptor denervated (SAD) or control (CON) male Sprague-Dawley rats, we determined: 1) concentration-dependent consumption of NaCl, 2) time course of saline intake, 3) effect of food access on saline intake, 4) intake of sucrose vs. saline, and 5) water vs. saline intake using a choice paradigm. In protocols 1-4 the rats were given a single bottle containing saline or sucrose for a 2-h period during the early dark period. A comparison of the intake of varying concentrations of NaCl (0.3 to 2.0% NaCl, six concentrations) demonstrated that the SAD consumed significantly less NaCl than the CON (from 0.9 to 2% NaCl), Saline Intake in SAD was 14-56% of the CON (significant group, salt concentration and interaction effects). Regression analysis demonstrated that in the SAD there was an inverse relationship between concentration and the amount of NaCl consumed (p < 0.02), an effect not seen in the CON. There were also differences in the pattern of saline intake with the CON showing the highest consumption in the early dark period with a gradual decrease as compared to the SAD, which demonstrated a uniformly lower pattern of consumption. The reduction in intake in the SAD appeared to be specific for NaCl because there was no difference in water or sucrose intake. The deficit could not be attributed to alterations in food intake, nor was there any difference in the amount of water consumed after the saline challenge.

Animals↗
PubMed1997

Concurrent partnerships and the spread of HIV.

OBJECTIVE: To examine how concurrent partnerships amplify the rate of HIV spread, using methods that can be supported by feasible data collection. METHODS: A fully stochastic simulation is used to represent a population of individuals, the sexual partnerships that they form and dissolve over time, and the spread of an infectious disease. Sequential monogamy is compared with various levels of concurrency, holding all other features of the infection process constant. Effective summary measures of concurrency are developed that can be estimated on the basis of simple local network data. RESULTS: Concurrent partnerships exponentially increase the number of infected individuals and the growth rate of the epidemic during its initial phase. For example, when one-half of the partnerships in a population are concurrent, the size of the epidemic after 5 years is 10 times as large as under sequential monogamy. The primary cause of this amplification is the growth in the number of people connected in the network at any point in time: the size of the largest "component'. Concurrency increases the size of this component, and the result is that the infectious agent is no longer trapped in a monogamous partnership after transmission occurs, but can spread immediately beyond this partnership to infect others. The summary measure of concurrency developed here does a good job in predicting the size of the amplification effect, and may therefore be a useful and practical tool for evaluation and intervention at the beginning of an epidemic. CONCLUSION: Concurrent partnerships may be as important as multiple partners or cofactor infections in amplifying the spread of HIV. The public health implications are that data must be collected properly to measure the levels of concurrency in a population, and that messages promoting one partner at a time are as important as messages promoting fewer partners.

Computer Simulation↗
PubMed1997

Prevalence study of the randomized controlled trials in the Journal of Intellectual Disability Research: 1957-1994.

Systematic reviews of care are increasingly potent guides to clinical practice, and it is important that all relevant randomized controlled trials (RCTs) are identified by those within the speciality of learning disability who produce such works. All RCTs in the Journal of Intellectual Disability Research and its predecessor were identified by hand-searching (1957-1994), and the frequency, origin, intervention and quality of reporting of randomization were described. Electronic searches for the trials were undertaken for the years 1974-1994, and the quality of indexing was inspected and tested. These electronic searches were then compared to a 'gold standard' search. Fifty-six RCTs were identified. None contained the world 'randomized' in the title and only nine mentioned it in the abstract. Out of the 37 RCTs published between 1974 and 1994, 36 are in PsycLIT and 37 in MEDLINE. One MEDLINE record contained the wrong abstract. The methodological phrases used in the electronic records were poor, and thus, the precision of electronic searches, using both databases, was low. This international journal contains many relevant RCTs from around the world, involving several types of interventions. Unfortunately, these trials cannot be readily accessed electronically using methodological phrases designed to find RCTs. Improved quality of indexing would facilitate identification of RCTs and their dissemination.

Cross-Sectional Studies↗
PubMed1997

Effects of antisense oligodeoxynucleotides on peptide release from hypothalamoneurohypophysial explants.

Rapid effects of antisense oligodeoxynucleotides (AODNs) on the function of the neurohypophysial system have been reported previously. The present studies were designed to determine the effects of vasopressin (VP) and oxytocin (OT) AODNs on osmotically or potassium-stimulated VP and OT release from perifused hypothalamoneurohypophysial (HNS) explants. The AODNs were 18-mer phosphorothioate forms targeted toward the translation initiation sites of either VP or OT mRNA, or a mixed base sequence (4 microM). The explants were exposed to a ramp increase in NaCl (either 20 or 30 mosmol/6 h) or to 25 mM KCl. VP and OT release was measured by radioimmunoassay in sequential 20-min fractions of the perifusate. There was a peptide-specific inhibition by the AODNs of osmotically stimulated VP and OT release. VP AODN inhibited VP, but not OT release, and vice vorsa. However, the AODNs had no effect on potassium-stimulated peptide release, demonstrating that depolarization-secretion coupling was still intact. Furthermore, there were no significant differences in VP and OT mRNA and peptide content after antisense treatment. Thus these observations indicate that acute exposure to peptide AODNs interrupts osmotically stimulated VP and OT release in a peptide-specific manner.

Animals↗
PubMed1997

Modulation of exercise tachycardia by vasopressin in the nucleus tractus solitarii.

Our objective was to study the role of vasopressinergic synapses at the nucleus tractus solitarii (NTS) in the modulation of exercise-induced tachycardia. We evaluated the effect of NTS administration of vasopressin (AVP) or vasopressin antagonist (AVP(ant)) on heart rate (HR) and mean arterial pressure (MAP) responses during dynamic exercise in male rats with chronic arterial and NTS cannulas. Sedentary (S) and trained (T) animals were tested at three or four exercise levels (from 0.4 up to 1.4 km/h) after NTS injection of AVP or AVP(ant) 20-30 min before treadmill exercise. Plasma and regional brain levels of AVP were measured in separate groups of S and T rats at rest and immediately after acute exercise. When administered into the NTS, exogenous AVP (20 pmol) caused a small but significant decrease in baseline HR and potentiated the tachycardiac response to mild to moderate exercise intensities (on average, increases of 35-46 beats/min over control tachycardic response). The potentiation of exercise tachycardia by AVP was long lasting and more pronounced in T than in S rats. Even 2 days after NTS AVP injection, there was evidence for an alteration in the HR response to exercise. Mediation by V1 receptors was supported by the blunted tachycardiac response to exercise after administration of a V1 antagonist d(CH2)5Tyr MeAVP into the NTS in both T and S rats (average reductions of 23-34 and 13-19 beats/min below control tachycardia, respectively). No changes were observed in baseline MAP or the exercise-induced pressor responses. There were specific changes in brain stem AVP levels that were related to the exercise treatment. T rats showed a marked increase in dorsal and ventral brain stem AVP content after acute exercise. There were no changes in hypothalamus, median eminence, posterior pituitary, or plasma AVP. These data indicate that vasopressinergic synapses and V1 receptors in the NTS are involved in the potentiation of tachycardic response to exercise. The vasopressinergic mechanism operates in both S and T rats, but training alters the sensitization of V1 receptors by AVP.

Animals↗
PubMed1997

Baroreceptor input regulates osmotic control of central vasopressin secretion.

Sinoaortic baroreceptor denervation (SAD) results in increased osmotically induced secretion of vasopressin (VP) and oxytocin (OT) and increased cardiovascular responses to many centrally acting pressor agents. Studies were conducted to determine whether SAD increases the cardiovascular and endocrine responses to direct and peripheral osmotic stimulation of the supraoptic nucleus (SON). SON microdialysis was performed in urethane-anesthetized male rats with measurement of dialysate peptides, mean arterial pressure (MAP) and heart rate. Experiment 1 tested the effect of direct stimulation of the SON with hypertonic NaCl in SAD, sham-operated (control) and intake-matched (matched) rats. Osmotically induced VP release into the SON was significantly greater in SAD than in control or matched groups. VP release peaked at 36 +/- 13 and 15 +/- 7 pg in SAD and controls, respectively, with no increase observed in the matched group. Plasma VP was significantly elevated after SON osmotic stimulation with no differences observed among the groups. The pressor response to osmotic stimulation was greater in SAD (29 +/- 4 mm Hg) than in control (20 +/- 3 mm Hg) and matched animals (15 +/- 3 mm Hg). Experiment 2 tested the effect of intraperitoneal injection of hypertonic NaCl on SON VP and OT release. SAD rats showed an increased central VP response to peripheral osmotic stimulation, a 64-fold increase in SAD as compared to a 4-fold one in controls. Central OT release was not significantly altered (peak of 22 +/- 6 vs. 11 +/- 4 pg, SAD vs. control). A direct SON osmotic challenge given 3.5 h after the intraperitoneal test confirmed an increased VP responsiveness in the SAD group. Plasma VP and OT were significantly increased after intraperitoneal hypertonic saline with no difference observed between groups. The MAP response to intraperitoneal hypertonic saline was greater in the SAD group with an elevation of 37 +/- 4 versus 18 +/- 3 mm Hg observed in SAD versus control subjects. These results demonstrate that baroreceptor denervation produces a state of heightened osmotic sensitivity for VP neurons, with evidence for increased central VP release to both direct and peripheral hypertonic NaCl stimulation.

Animals↗
PubMed1997

Postnatal depression and elation among mothers and their partners: prevalence and predictors.

BACKGROUND: Correlates and predictors of mood disturbances at 3 days and 6 weeks postpartum were assessed in Irish mothers and their partners. METHOD: The Edinburgh Postnatal Depression Scale (EPDS) and the Highs Scale were used to assess 370 mothers and their partners. Socio-demographic, clinical and obstetric data were collected at patients' first antenatal visit. Factors associated with EPDS scores of > or = 13 and Highs score of > or = 8 were examined. RESULTS: On the EPDS 11.4% of mothers scored > or = 13 at 3 days postpartum and 11% at 6 weeks, while 18.3% of mothers scored > or = 8 on the Highs Scale at 3 days and 9% at 6 weeks. Scores on the EPDS and Highs Scale were interrelated. Factors associated with EPDS scores of > or = 13 at 6 weeks were single status, unemployment, unplanned pregnancy, public status and bottlefeeding. The best predictors of EPDS > or = 13 at 6 weeks were mothers' scores on the EPDS and the Highs Scale at 3 days. Three per cent of partners scored > or = 13 on the EPDS at 3 days postpartum and 1.2% at 6 weeks. CONCLUSIONS: Factors associated with mothers' mood disturbance were readily identifiable and collected routinely at antenatal intake. Mothers' mood within 3 days of delivery was the best predictor of later postnatal depression. Paternal mood disturbance was rare. Certain women may be at increased risk for postnatal mood disturbance and may be amenable to early identification and intervention.

Bipolar Disorder↗
PubMed1997

Gender differences in health-related quality of life among postmyocardial infarction patients: brief report. CAST Investigators. Cardiac Arrhythmia Suppression Trials.

Heart disease is the leading cause of death among women in the United States. The prognosis for heart disease is worse for women than for men. Also, although women are less likely than men to initially present with a myocardial infarction (MI), they are more likely to die following an MI. A number of factors have been identified that partially account for the gender difference in post-MI morbidity and mortality. However, limited data are available on the sex differences in clinical, psychosocial, and demographic factors that may combine to explain the poorer prognosis for women following an acute MI. The Cardiac Arrhythmia Suppression Trials collected detailed demographic, clinical, and psychosocial data on 2,043 men and 448 women following acute MIs. Analyses indicate that women had a worse clinical, socioeconomic, and psychosocial profile than did men. In addition, significant differences in psychosocial profiles persisted after controlling for demographic and clinical data, suggesting that women presenting with MIs have a cluster of complex factors that put them at high risk for morbidity and mortality following an MI. Future longitudinal studies that include adequate numbers of women as well as reliable assessments of both clinical and psychological variables are needed to better understand the factors that influence the poor prognosis for women with coronary heart disease.

Adult↗
PubMed1997

Potential of electrospray mass spectrometry for quantifying glycohemoglobin.

An electrospray ionization-mass spectrometric procedure has been developed for determining glycohemoglobin. Whole-blood samples from 78 diabetic and 50 nondiabetic subjects (glycation range 3-15%, as determined by electrospray mass spectrometry) were diluted 500-fold in an acidic denaturing solvent and introduced directly into a mass spectrometer. The resulting mass spectra were then processed to estimate the percentage of glycohemoglobin present in the sample. Total analysis time, including plotting the spectra and computing the percentage of glycation, was approximately 3 min. The imprecision (CV) of the method was < 5.1% for inter- and intrabatch analyses for total glycohemoglobin in the range 3.6-14%. Comparison of the mass spectrometric results with those from established affinity chromatographic procedures showed good overall agreement. The relative glycation of the alpha- and beta-chains was determined directly and was shown to be constant (0.64:1) over the glycation range measured. Only single glucose attachment to both the alpha- and beta-chains was observed.

Chromatography, Affinity↗
PubMed1997

The re-based 1991 population estimates by marital status.

Shortly after preparing the re-based 1991 population estimates, the Office for National Statistics produced provisional population estimates by legal marital status (for England and Wales as a whole). These provisional estimates were calculated using a marital status distribution for 1991 that was updated from the 1981 Census. These estimates have now been revised to incorporate marital status information from the 1991 Census. This article outlines the options for re-basing the estimates, the method used, and assesses the effect of the revision on the rates of marriage, divorce and mortality by single year of age. The main differences between the provisional and final re-based estimates in 1991 are: estimates of widowed men and women are 7 per cent and 2 per cent higher, respectively, estimates of divorced men and women are 2 per cent and 3 per cent lower, re-marriage rates (amongst the divorced or widowed) for men 50-59 increased, and mortality rates for single and divorced men increased for those aged over 70.

Adolescent↗