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Biomedical subjects

M Morris

Publications and source records attributed to M Morris.

At least 127 records · Page 7Linked to original sources
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

Adolescent sexual networking and HIV transmission in rural Uganda.

Information on 861 adolescents shows that in 1991 36 per cent reported having been sexually active in the previous 12 months, but only 6.2 per cent had ever used a condom (11% males, 2.4% females). The HIV infection rate was 5.9 per cent overall, 0.8 per cent in males and 9.9 per cent in females. The proportion sexually active and the rate of HIV infection rise with age. The annual incidence of HIV infection was 2.0 per 100 person-years of follow-up among all adolescents, 0.8 in males and 3.0 in females. The annual mortality rate among HIV-negative adolescents was 0.37 per cent versus 3.92 per cent among the HIV-positive adolescents, a rate ratio of 10.6. Sexual network data were collected on 389 adolescents aged 15-19 years of whom 55 per cent were sexually active. The median age of first sexual intercourse was 15 years in either sex. The 214 adolescents reported 339 sexual relationships of which 38.5 per cent were with spouses, 36 per cent with boy or girl friends and 21 per cent with 'friends'. There were 52 concurrent sexual relationships reported by 35 adolescents. Males report higher rates of concurrent sexual relationships than females. The sexual partners of boys were mainly younger students and housemaids while the girls' partners were mainly older traders and salaried workers. Adolescents in this community report high rates of sexual activity and have complex sexual networks. They probably are important in the dynamics of HIV infection.

Adolescent↗
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↗
PubMed1996

Acute renal failure in the paediatric intensive care unit.

AIMS: To review a group of children with acute renal failure (ARF) requiring renal replacement therapy in a paediatric intensive care unit (PICU). METHODS: Case records of children admitted to paediatric intensive care unit between January 1992 and July 1995 were reviewed for demography, diagnosis, modality of treatment, duration, complications of therapy and renal outcome. Long term follow up was sought from patients' referring paediatricians. RESULTS: Twenty children with a mean age of 2 years and 3 months required acute renal replacement therapy. The most common cause was diarrhoea associated haemolytic uraemic syndrome with a mean duration of dialysis of 11.5 (SD 3.1) days (range 5-15. Four children had septicaemic illnesses; three with multiorgan system failure, one of whom died. Peritoneal dialysis was the only modality in 16 patients and four children were treated with continuous venovenous haemofiltration. Eight of the 20 patients were discharged from the paediatric intensive care unit with normal renal function as judged by serum creatinine. Long-term follow up showed normalisation of serum creatinine in a further eight of ten patients. CONCLUSIONS: The most common cause of acute renal failure was diarrhoea associated haemolytic uraemic syndrome with an excellent outcome (100% patient survival). Children who had acute renal failure due to other illnesses had a higher mortality (27%).

Acute Disease↗
PubMed1996

Sexual adjustment of patients undergoing gracilis myocutaneous flap vaginal reconstruction in conjunction with pelvic exenteration.

BACKGROUND: Although the technique for gracilis myocutaneous vaginal reconstruction was first described in the mid-1970s and has been used in conjunction with pelvic exenteration since that time, there is little available information regarding sexual adjustment after such a procedure. The purpose of this study was to assess the sexual adjustment of women who underwent pelvic exenteration and gracilis myocutaneous vaginal reconstruction at the study institution. METHODS: In a prospective study design, 95 patients were identified who underwent pelvic exenteration and gracilis myocutaneous vaginal reconstruction at the study institution from 1977 through 1989 and a convenience sample was selected of 44 patients who completed a modified version of the Sexual Adjustment Questionnaire (SAQ) when they returned to the gynecologic oncology outpatient clinic for routine follow-up care. A vaginal assessment was also performed by the attending physician. RESULTS: Twenty-one of 40 patients (52.5%) completing the questionnaire reported not resuming sexual activity after surgery; 19 patients reported sexual activity between 1.5 months to 12 years postoperatively. Of the patients who resumed sexual activity, 84% did so within 1 year of surgery. The most common problems noted by patients in adjusting to sexual activity after surgery were self-consciousness about the urostomy or colostomy and being seen in the nude by their partner, vaginal dryness, and vaginal discharge. The mean rank of preexenteration SAQ scores was 66.4, and the mean rank of postexenteration scores was 48.7 (P < 0.0001), demonstrating that sexual adjustment after exenteration was significantly poorer than before the surgery. On the basis of data gathered from a vaginal assessment form, 31 of 44 patients (70.4%) were judged to have a potentially functional neovagina. CONCLUSIONS: Based on the findings of this questionnaire study, sexual adjustment is often significantly impaired in women after pelvic exenteration and gracilis myocutaneous vaginal reconstruction. Future modifications in surgical technique, more realistic patient counseling and aggressive postoperative support will hopefully minimize such problems.

Adaptation, Psychological↗
PubMed1996

Salt loading abolishes osmotically stimulated vasopressin release within the supraoptic nucleus.

Central and systemic osmotic stimulation increase vasopressin (VP) release within the supraoptic nucleus (SON) and into the general circulation. We examined whether changes in water/electrolyte balance affect the neurosecretory responses to these stimuli. Urethane-anesthetized control, salt-loaded (2% NaCl for 2 days) or water-deprived (for 2 days) male rats were implanted with an arterial catheter and bilateral microdialysis probes into the SON. Plasma and SON VP levels were measured before and after acute osmotic stimuli were administered intraperitoneally (i.p.) and then directly into the SON. Water deprivation resulted in elevated basal intranuclear and plasma VP levels. Intraperitoneal hypertonic saline (HS) and direct osmotic stimulation of the SON increased VP release into the SON in both the control and water-deprived groups. Salt loading abolished the intranuclear VP response to both stimuli. Osmotically induced release of VP into plasma was not different between the three groups. These data demonstrate that salt loading, but not water deprivation, alters the central neurosecretory VP response to acute osmotic stimulation.

Animals↗
PubMed1996

A novel silent posttranslational mechanism converts methionine to aspartate in hemoglobin Bristol (beta 67[E11] Val-Met->Asp).

The first reported case of congenital Heinz body hemolytic anemia was subsequently shown to be caused by an unstable hemoglobin, Hb Bristol [beta 67(E11) Val-Asp]. This has become one of the classic models of an unstable hemoglobin, the hydrophilic aspartate disrupting the hydrophobic heme pocket. We have restudied this original case, who remains clinically well after nearly 50 years of severe hemolysis with a hemoglobin level of about 7 g/dL and two unrelated Japanese cases. Surprisingly, all three cases show the same DNA changes, predicting a valine to methionine change at beta 67, rather than the expected aspartate. Further analysis with electrospray ionization mass spectrometry and globin chain biosynthesis strongly suggests that this anomaly is because of a novel posttranslational mechanism, with slow conversion of the translated methionine into an aspartate residue. The proximity of the heme and oxygen may be important in facilitating the reaction. These findings show the importance of complete characterization of variant hemoglobins using protein, DNA, and biosynthetic analyses.

Adolescent↗
PubMed1996

Measures of concurrency in networks and the spread of infectious disease.

An investigation is made into the impact of concurrent partnerships on epidemic spread. Starting from a definition of concurrency on the level of individuals, the authors define ways to quantify concurrency on the population level. An index of concurrency based on graph theoretical considerations is introduced, and the way in which it is related to the degree distribution of the contact graph is demonstrated. Then the spread of an infectious disease on a dynamic partnership network is investigated. The model is based on a stochastic process of pair formation and separation and a process of disease transmission within partnerships of susceptible and infected individuals. Using Monte Carlo simulation, the spread of the epidemic is compared for contact patterns ranging from serial monogamy to situations where individuals can have many partners simultaneously. It is found that for a fixed mean number of partners per individual the distribution of these partnerships over the population has a major influence on the speed of the epidemic in its initial phase and consequently in the number of individuals who are infected after a certain time period.

Acquired Immunodeficiency Syndrome↗
PubMed1996

A comparison of end and loop colostomy for fecal diversion in gynecologic patients with colonic fistulas.

OBJECTIVE: The purpose of this study was to evaluate the early morbidity, stomal complications, and overall survival rate of gynecologic oncology patients treated with end or loop colostomy for management of colonic fistula. METHODS: Seventy-five women with fistulas undergoing fecal diversion procedures from 1983 to 1993 were identified. Information relevant to tumor history, type of fistula, operative procedure, complications, and outcome was extracted from the medical records. RESULTS: A recto- or sigmoid-vaginal fistula was present in 55 patients. The remaining 20 patients had either a colonic fistula involving the bladder, uterus, or skin or multiple fistulas. In 66 (88%) patients, the pelvis had been irradiated. Loop colostomy was performed in 47 (63%) patients and end colostomy in 28 (37%) of patients. Cancer was present in 31 (66%) of 47 patients undergoing loop colostomy compared with 12 (43%) of 28 patients undergoing end colostomy (P = 0.05). No significant differences were detected with regard to age at cancer diagnosis or age at the time of colostomy, body habitus, medical condition, type of cancer, history of pelvic irradiation, or incidence of multiple or complex fistulas. Median operative time was increased by 1 hr and median blood loss from 50 to 200 ml with end colostomy. No significant advantage of loop colostomy over end colostomy was detected in the incidence of acute morbidity or hospital stay. Early stomal complications occurred in 8 patients, 7 of whom had loop colostomy (P = 0.25). Delayed complications (prolapse, retraction, stool per vagina, or fistula) following loop colostomies occurred more frequently than following end colostomy: 12 (26%) of 47 compared with 2 (7%) of 28 (P = 0.05), respectively. Five loop stomas were later converted to end stomas. In addition only one of four attempted loop colostomy closures was successful. Overall survival in both groups of patients was similar. CONCLUSION: There were no statistically significant differences between patients treated with loop or end colostomy with regard to early morbidity or survival. The early and frequent occurrences of stomal complications after loop colostomy overshadow the clinically minor advantages of this method of fecal diversion. Although loop colostomy was performed more often in this setting, these data do not support its routine use for the management of gynecologic oncology patients with fistulas.

Colonic Diseases↗
PubMed1996

Treatment of recurrent adenocarcinoma of the endometrium with pelvic exenteration.

Women with recurrent endometrial carcinoma are usually not considered candidates for pelvic exenteration. To assess the efficacy of this procedure, the records of all patients undergoing pelvic exenteration for adenocarcinoma of the endometrium at four institutions from 1955 through 1988 were reviewed. Of the 31 procedures performed, 7 were for primary therapy and 4 were judged to be palliative in nature and were excluded from analysis. Of the 20 patients with recurrent endometrial cancer who underwent exenteration with curative intent, all had previously received pelvic radiotherapy, 14 as part of their primary treatment and 6 as part of the treatment of recurrent disease. Six of 20 patients also received chemotherapy or hormonal therapy prior to exenteration. The median patient age was 65 years (range 44-79 years). At most recent follow-up, 8 patients were alive and disease free, 2 were alive with disease, 6 had died of disease, and 4 had died of other causes. The median follow-up of living patients is 89 months. Twelve of 20 patients experienced major complications, the most common of which was neovaginal flap necrosis. Of the 20 patients, 1 patient (5%) died in 1963 of surgical complications. The Kaplan-Meier estimate of 5-year disease-free survival is 45%. Pelvic exenteration can produce an acceptable rate of disease-free survival in highly selected patients with local recurrence of endometrial adenocarcinoma who have exhausted other treatment modalities.

Adenocarcinoma↗
PubMed1996

Groin dissection practices among gynecologic oncologists treating early vulvar cancer.

OBJECTIVE: To survey the surgical practice of gynecologic oncologists regarding the extent of groin dissection for early vulvar cancer. METHODS: A 14-item questionnaire was developed and presented to the Annual Meeting of the Felix Rutledge Society. Gynecologic oncologists were asked to describe in descriptive, categorical, and visual terms the groin procedure that they perform as part of management of early vulvar cancers. Three ink-line drawings were created by a medical illustrator for the purpose. Fifty returned surveys were evaluable. RESULTS: The most commonly performed procedures were removal of the lymph nodes above the cribriform fascia and those medial to the femoral vein (40%), removal of lymph nodes above the cribriform fascia (34%), and removal of all nodes above and below the cribriform fascia (22%). Respondents performing the first procedure termed it "superficial inguinal lymphadenectomy" (40%), "inguinal femoral lymphadenectomy" (25%) and a variety of other names (35%). Respondents performing the second two procedures were much more consistent in the figure and name that they matched with their description of the nodes removed. When respondents were asked to match the figures with categorical definitions based on their understanding of the literature, the figure depicting Scarpa's triangle following removal of the superficial inguinal and medial femoral nodes was named superficial inguinal lymphadenectomy by 24% despite the fact that the femoral vein was clearly visible and labeled. CONCLUSIONS: We conclude that (1) among this group of gynecologic oncologists superficial inguinal and medial femoral lymphadenectomy is the most commonly performed procedure for women with early vulvar cancer and that the procedure is frequently called superficial inguinal lymphadenectomy; (2) publications and protocols on this topic must provide complete descriptions of procedures performed, and investigators must assure that individual surgeons are performing the same procedure; and (3) treatment results with superficial inguinal and medial femoral lymphadenectomy are poorly described and a fertile area for further study.

Female↗
PubMed1996

Intraabdominal lymphatic mapping to direct selective pelvic and paraaortic lymphadenectomy in women with high-risk endometrial cancer: results of a pilot study.

OBJECTIVE: To determine the feasibility of intraperitoneal lymphatic mapping of the uterine fundus as a means of identifying target sites for lymph node biopsy during staging laparotomy and to develop preliminary experience with the technique. METHODS: Fifteen women with high-risk endometrial tumors were entered on this Institutional Review Board-approved pilot study. At laparotomy, isosulfan blue dye (1.0 ml) was injected into the subserosal myometrium at three sites: the superior midpoint of the fundus, 2 cm inferiorly on the anterior wall, and 2 cm inferiorly on the posterior wall. Dye uptake into lymphatic channels was observed for 10 min. The retroperitoneal spaces were opened. Blue lymphatic channels and nodes within the pelvic and paraaortic regions were identified. Nodes demonstrating dye uptake were biopsied as separate specimens: the locations of these nodes were carefully recorded. Hysterectomy and selective lymphadenectomy were then performed as usual. RESULTS: Lymphatic channels coursing into the broad ligament and along the ovarian vessels were identified from all uteri injected. Deposition of dye into grossly identifiable lymph nodes was seen in 10 of 15 cases (67%). A total of 31 nodes demonstrated dye uptake. The locations of these nodes included paraaortic sites in 12, common iliac in 6, and pelvic in 13. No dye-containing paraaortic nodes were seen below the origin of the inferior mesenteric artery. Lymphatic channels coursing above the renal vessels were seen routinely. Microscopic nodal metastases to sentinel nodes were identified in 2 of 4 women with proven lymphatic spread. CONCLUSIONS: Lymphatic mapping of the uterine fundus is feasible and can identify targets for selective nodal biopsy in some women. Preliminary observations confirm that the lymphatic network draining the uterus is complex and involves both pelvic and paraaortic nodes. Lymphatic channels that parallel the ovarian vessels were not observed to enter nodes until reaching the level of the midabdomen. Further experience and refinement of techniques may lead to the development of a selective lymphadenectomy based upon direct visualization of the lymphatic drainage of the uterus rather than the current random sampling.

Aorta↗