Search PubMed⌕ Search

Biomedical subjects

M Morris

Publications and source records attributed to M Morris.

At least 235 records · Page 13Linked to original sources
PubMed1994

Endocrine changes associated with a rapidly developing sodium appetite in rats.

Simultaneous administration of the diuretic furosemide (10 mg/kg) and a low dose of the angiotensin-converting enzyme (ACE) inhibitor captopril (5 mg/kg) results in short-latency thirst and sodium appetite (i.e., the rapid ingestion of water and NaCl solution). To elucidate potential mechanisms for mediating this behavior, changes in plasma levels of key hormones involved in fluid intake and balance were characterized in rats subjected to this treatment protocol. Rats treated jointly with furosemide and low-dose captopril had exaggerated increases in plasma renin activity and angiotensin I but equivalent increases in plasma aldosterone compared with rats treated with either agent alone. Treatment with furosemide plus low-dose captopril increased plasma vasopressin but not plasma oxytocin. The administration of a higher dose of captopril (100 mg/kg) with furosemide, a combination of drugs that does not stimulate fluid intake (29), further increased plasma renin activity and angiotensin I but prevented the rise in plasma vasopressin. The results support the hypothesis that thirst and salt appetite generated by this protocol depend on angiotensin II formed within brain circumventricular organs rather than the systemic circulation.

Aldosterone↗
PubMed1994

Dissociation between vasopressin and oxytocin mRNA and peptide secretion after AV3V lesions.

The effect of hypertonic NaCl consumption on vasopressin (VP) and oxytocin (OT) mRNA levels and plasma and pituitary peptides was evaluated in rats with sham or anterior ventral third ventricular (AV3V) lesions. Rats were given tap water or 2% NaCl for 4 days. Because the rats with lesions drank significantly less salt solution than the controls (78.8 +/- 17.4 vs. 205.5 +/- 37.8 ml/4 days), a second control group was included in which saline intake was matched to the lesioned group. AV3V rats showed a deficit in the peptide response to the osmotic stimulus. There was no increase in plasma VP or OT or decrease in posterior pituitary peptide content in the face of an extreme hypernatremia: plasma sodium of 180.1 +/- 4.2 meq/l. Evaluation of mRNA changes by means of in situ hybridization showed that animals with lesions responded to the salt challenge with increases in hypothalamic VP and OT mRNA levels. There were significant increases in paraventricular and supraoptic OT mRNA and paraventricular VP mRNA in the lesioned group. The salt-matched control group showed no changes in peptide mRNA levels. These results demonstrate that AV3V lesions produce an impairment of the salt-neuroendocrine reflex but a persistence of the peptide mRNA response. Differences in control mechanisms must account for this dissociation between peptide mRNA expression and peptide secretion.

Animals↗
PubMed1994

Salvage surgery for chemorefractory gestational trophoblastic disease.

PURPOSE: To investigate and define better the role of salvage surgery for patients with chemorefractory gestational trophoblastic disease (GTD). PATIENTS AND METHODS: A retrospective review of medical records at The University of Texas M.D. Anderson Cancer Center identified 33 patients with chemorefractory GTD who underwent salvage surgery between 1962 and 1991. The end points selected for analysis were serologic response and survival. RESULTS: Initial salvage procedures consisted of 29 hysterectomies, four thoracotomies, and one nephrectomy (in conjunction with a hysterectomy). Fourteen patients (42%) had a serologic complete response (CR) to surgery (normalization of human chorionic gonadotropin [hCG]), 10 (30%) had a partial response (> 50% decrease in hCG level), and nine had no response (< or = 50% decrease in hCG level). Of 19 patients who received further chemotherapy, eight (42%) attained a CR. Four patients underwent a second salvage surgery: two thoracotomies, one craniotomy, and one partial hepatectomy. All achieved a CR. The probability of achieving a CR was influenced by the time from diagnosis to surgery, number of preoperative disease sites, preoperative World Health Organization (WHO) score, and histologic type. Survival was influenced by the type of antecedent pregnancy, number of preoperative regimens, number of preoperative disease sites, time from diagnosis to surgery, and preoperative WHO score. CONCLUSION: Based on the findings of this study, it appears that a select subset of patients with chemorefractory GTD who have a limited number of clinically detectable tumor foci may benefit from salvage surgery.

Adult↗
PubMed1994

Insulin receptor down-regulation and impaired antilipolytic action of insulin in diabetic patients after pancreas/kidney transplantation.

Patients with insulin-dependent diabetes who receive pancreas/kidney transplants lose their need for insulin injections, but they become hyperinsulinemic and insulin resistant, and sometimes develop noninsulin-dependent diabetes mellitus. The reason for the insulin resistance is not well understood. Specifically, it is not known whether they become resistant to the action of insulin on lipid metabolism. Euglycemic-hyperinsulinemic clamps were performed in six pancreas/kidney (P/K) recipients, six kidney (K) recipients (to control for immunosuppressive therapy), and eight healthy controls. Measured were leg blood flow (by plethysmography), rates of lipolysis (with [2H5] glycerol), fatty acid oxidation (by indirect calorimetry), fatty acid reesterification (with [2H5]glycerol and [1-13C]palmitate), monocyte membrane insulin binding (with [125I]Tyr-A14 insulin), and insulin receptor mass (by RIA). Fasting plasma insulin concentrations were 2 times higher in P/K and K recipients (108 pmol/L) than in controls (54 pmol/L). Insulin receptor mass in solubilized monocyte membranes from P/K and K recipients was reduced by 61% and 63%, respectively, whereas insulin binding was reduced by 73% and 70%, respectively. P/K and K recipients were resistant to the inhibitory action of insulin on lipolysis (P/K vs. controls, P < 0.01; K vs. controls, P < 0.02) and on fatty acid reesterification (P/K vs. controls, P < 0.02; K vs. controls, P < 0.03). P/K recipients appeared to be more resistant than K recipients, but the differences between the two groups were not statistically significant. We conclude that P/K recipients were hyperinsulinemic, had down-regulated the number of their monocyte insulin receptors, and were resistant to the antilipolytic action of insulin.

Adult↗
PubMed1994

Dextran-coated superparamagnetic iron oxide, an MR contrast agent for assessing lymph nodes in the head and neck.

PURPOSE: To investigate dextran-coated superparamagnetic iron oxide particles (BMS 180549) as an MR contrast agent for assessing lymph nodes. METHODS: Five different doses ranging from 0.3 to 1.7 mg Fe/kg were evaluated in five healthy human male subjects as part of a phase 1 clinical study. T1-, T2-, and proton density-weighted spin-echo images as well as multiplanar gradient-echo and spoiled gradient-echo images were acquired before and 1 hour, 4 hours, and 24 hours after contrast administration. Image analysis was performed with visually selected regions of interest. Signal intensities were measured for neck lymph nodes and the adjacent muscle. Enhancement effects were evaluated as a function of dose, imaging time after contrast administration, and MR pulse sequence. RESULTS: The iron oxide particles were phagocytized by macrophages within the normal functioning lymph nodes, resulting in a dramatic decrease in signal intensity because of magnetic susceptibility effects. T2*-weighted gradient echo and T2-weighted spin echo showed significant decrease in the signal intensity of normal lymph nodes at 24 hours after contrast injection at a dose of 1.7 mg Fe/kg. No significant changes in lymph node signal intensity on T1-weighted spin-echo images were noted at any dose or imaging time point. CONCLUSIONS: This preliminary clinical evaluation demonstrates intravenous delivery of an iron-based contrast agent, resulting in negative enhancement of normal lymph nodes.

Adult↗
PubMed1994

Qualitative and quantitative effects of running on mood.

This study examines the assumption that the dimensional structure of mood following strenuous physical exercise is unchanged by comparison with that beforehand. A specially-devised adjective checklist was completed by 165 regular runners 5-10 minutes before, and immediately after, a 3-mile run. Principal components analyses of the scores revealed independent dimensions of positive and negative affect which were similar on both occasions. There was no evidence of a separate major dimension of elation or well-being after running. The structure of mood differed before and after running only in minor components. Component-based scale scores were calculated for each subject, for each occasion. Positive mood was increased, and negative mood decreased, after running. The main changes in mood caused by running in these conditions are therefore quantitative rather than qualitative. Improvements in mood were greater in women than in men, largely because women experienced a worse mood state than did men before running.

Adult↗
PubMed1994

Closure of complex vulvar defects using local rhomboid flaps.

Because primary closure under tension is frequently associated with wound breakdown and prolonged healing, we have used local rhomboid flaps as a technique for vulvar reconstruction when primary closure is not adequate. We evaluated the range of clinical applications, perioperative and long-term complication rates, length of hospital stay, and patient reaction to the rhomboid flap repair. Fifteen rhomboid flaps were constructed in 13 patients who underwent extensive vulvar resections between 1989-1994. Partial primary closure was combined with flap construction in 11 patients. Flap size ranged from 2.5 x 2.5 to 6 x 6 cm. Two women had minor wound separations. There were no other early or delayed vulvar complications. The six women with partners were able to resume sexual activity postoperatively. Rhomboid flaps provide excellent design flexibility for closure of large complex vulvar defects with minimal morbidity and acceptable cosmetic and functional results.

Adult↗
PubMed1994

Secondary cytoreductive surgery for ovarian cancer.

Secondary cytoreduction to optimal levels can be successfully accomplished in a substantial number of ovarian cancer patients and in a variety of clinical settings. Although frequently complex, secondary operations can be performed with acceptable morbidity. All operations should be undertaken by experienced oncologic surgeons. Prospective randomized clinical trials to evaluate the survival benefits of secondary cytoreduction will probably never be conducted. Consequently, estimates of survival benefit must be derived from the evaluation of outcome in clinically homogeneous subsets. There is good evidence that a survival advantage can be obtained in patients whose gross disease is completely resected at second-look laparotomy and in patients whose disease recurs after a complete response to primary cytoreduction and cisplatin-based chemotherapy. Patients who fail to respond to primary treatment are probably not appropriate candidates for a secondary resection. Because most patients are left with at least microscopic residual disease, the lack of effective second-line chemotherapy limits the survival impact of secondary cytoreduction.

Antineoplastic Agents↗
PubMed1994

Management of ureteral stenosis after renal transplantation.

BACKGROUND: Ureteral stenosis is the most common urologic complication of renal transplantation. Preferred management options for this complication vary among centers. Ureteral stenosis occurred in 24 (3.4 percent) of 692 consecutive renal transplants. The diagnosis was confirmed by antegrade pyelography after ultrasonography in all instances. An attempt was made to treat all patients by percutaneous stenting, usually with dilatation of the ureter, which was possible in 21 patients. In three patients, a wire could not be passed across the stricture and these patients were treated surgically. STUDY DESIGN: The patients were divided into two groups. Patients in group 1 (14 patients) presented within three months from the date of transplantation and patients in group 2 (seven patients) presented after three months. RESULTS: The site of stenosis was the ureterovesical junction in 80 percent of the patients and the uretero-pelvic junction in 20 percent. Urinary tract infection occurred in 70 percent of the patients in group 1 and 100 percent of patients in group 2. The success rate of percutaneous stenting was 71 percent (ten of 14 patients) in group 1, but only 29 percent (two of seven patients) in group 2. The failures were treated by repeated stenting (one patient in each group) or by operation. One allograft (7 percent) was lost in group 1 and two (28 percent) were lost in group 2. The average follow-up period was 38 months in group 1 and 56 months in group 2. There was no mortality in this series. CONCLUSIONS: Ureteral stenosis in the early postrenal transplant period can be safely and effectively treated by percutaneous dilatation and stenting, with few side effects and long-term success. This method is specially efficacious in patients who present within three months from the time of their transplant. In patients who have ureteric strictures developing after three months from transplantation, percutaneous stenting is of limited value and most patients require surgical correction.

Adult↗
PubMed1994

Intraoperative lymphatic mapping for vulvar cancer.

OBJECTIVE: To determine the feasibility of intraoperative lymphatic mapping in patients with vulvar cancer. METHODS: Isosulfan blue was injected intradermally at the junction of tumor and normal skin in nine patients. We then attempted to identify the dye in the superficial lymphatic channels and in a superficial groin lymph node. RESULTS: The sentinel node was identified in seven of 12 groins in seven of the nine subjects studied. Six of the successful cases had unilateral lesions. The cases in which a sentinel node was not identified were both patients with midline lesions, including one whose scar was injected following a prior wide local excision of a perineal tumor and one who appeared to have direct drainage to the deep pelvic nodes. There were no technique-related complications. In no case was there a positive non-sentinel node in the presence of a negative sentinel node. CONCLUSION: Intraoperative lymphatic mapping is technically feasible in patients with vulvar cancer, particularly those with unilateral disease. Further experience is needed to evaluate the reliability of the technique in identification of groin node metastases.

Carcinoma, Squamous Cell↗
PubMed1993

Telling tails explain the discrepancy in sexual partner reports.

An anomaly often noted in surveys of sexual behaviour is that the number of female sexual partners reported by men exceeds the number of male partners reported by women. This discrepancy is sometimes interpreted as evidence that surveys produce unreliable data due to sex-linked response and sampling bias. We report here that among the 90% of respondents reporting fewer than 20 lifetime partners, however, the ratio of male to female reports drops from 3.2:1 to 1.2:1. The anomaly thus appears to be driven by the upper tail of the contact distribution, an example of the general principle of outlier influence in data analysis. The implication is that sexual behaviour surveys provide reliable data in the main, and that simple improvements can increase precision in the upper tail to make these data more useful for modelling the spread of AIDS and other sexually transmitted diseases.

Data Interpretation, Statistical↗
PubMed1993

Psychosocial predictors of mortality in the Cardiac Arrhythmia Suppression Trial-1 (CAST-1).

Psychosocial variables predict the recurrence of clinical events in symptomatic patients, controlling for measures of disease severity. The Cardiac Arrhythmia Suppression Trial-1, a pharmacologic test of the arrhythmia suppression and mortality hypothesis among postmyocardial infarction patients, allowed a prospective test of the relationship of distress, perceived support, social interaction, life stress, and other variables, to mortality, adjusting statistically for ejection fraction, arrhythmia rates, and other known risk factors for coronary heart disease. Results indicated that the treatment medications, encainide and flecainide, were powerful predictors of mortality. Although the psychosocial variables were significant as univariate predictors, these variables were not significant as predictors in a multivariate model that included drug treatment. When the data analysis was restricted to patients randomized to placebo, thereby eliminating the antiarrhythmic drug effect, the level of perceived social support was a significant multivariate predictor of mortality, adjusting for measures of disease severity. The adjusted hazards ratio for a 1-point decrease in the perceived support score is equal to 1.46, based on the multivariate model.

Arrhythmias, Cardiac↗
PubMed1993

Age contrasts in patients with advanced epithelial ovarian cancer. The M.D. Anderson Cancer Center experience.

BACKGROUND: This study reviews the experience at the University of Texas M.D. Anderson Cancer Center with elderly patients treated for advanced epithelial ovarian cancer with cisplatin-based combination chemotherapy. METHODS: From 1978 through 1988, 215 patients with Stage III or IV, Grade 2 or 3 epithelial ovarian cancer were entered onto one of three consecutive trials involving cisplatin-based combination chemotherapy. The treatment plans were as follows: Trial 1: 12 cycles of cisplatin-melphalan (75 patients); Trial 2: 12 cycles of cisplatin-cyclophosphamide (49 patients); and Trial 3: 6 cycles of cisplatin-cyclophosphamide (91 patients). End-points of analysis included the effect of age on other prognostic factors, clinical response rate, surgical response rate, toxicity, progression-free survival, and survival. RESULTS: Of the entire study group, 57 patients (27%) were 65 years of age and older at diagnosis. There was no effect of age on FIGO stage or histologic grade distribution, but 61% of patients younger than 65 years of age had residual tumors less than or equal to 2 cm compared with only 33% of patients 65 years of age and older (P = 0.00027). There were no differences between the two age groups with respect to response rates, recurrence rate after negative second-look surgery, toxicity, or progression-free survival. Patients in the younger than 65 years of age group, however, had a significantly longer median survival time than those 65 years of age and older (30 versus 19 months, respectively) (P = 0.0038). CONCLUSIONS: This analysis suggests that elderly patients are more likely to begin chemotherapy with bulky residual disease and to have a significantly shorter survival time than their younger counterparts.

Adult↗
PubMed1993

Reluctance to undergo predictive testing: the case of Huntington disease.

The development of a presymptomatic test for Huntington Disease (HD) has enabled some persons at risk to determine whether or not they are gene carriers. The purpose of this study was to explore the reasons why those at risk choose not to be tested in a situation where testing is available and most of the test-associated costs are covered by state funding. Subjects were also asked their levels of knowledge about testing, attitudes towards aspects of the testing protocols, and intentions towards testing once the gene for HD is found. Sixty-six individuals at risk for HD who had chosen not to be tested completed a mailed questionnaire. The most important reasons for not being tested were increased risk to children if one was found to be a gene carrier, absence of an effective cure, potential loss of health insurance, financial costs of testing, and the inability to "undo" the knowledge. Individuals comprising this sample were quite knowledgeable about predictive testing. Most supported the availability of testing despite the lack of a cure, the need for special counseling prior to testing, and the idea that testing should be a voluntary decision. Most said they would take the test if a treatment was available, if the mechanics of the test were simplified, or if the test was 100% accurate. The risk to relatives, lack of treatment or cure, fear of losing one's health insurance, and the accuracy of the information to be gained from testing are important factors in the decision not to be tested.

Adult↗
PubMed1993

A comparative study of speech after total laryngectomy and total laryngopharyngectomy.

Quality of voice is an important factor in the consideration of treatment for advanced laryngeal cancer. This prospective study compared the speaking proficiency of patients who used the Blom-Singer valve after total laryngectomy and after total laryngopharyngectomy with jejunal graft reconstruction with that of a group of normal subjects. The total laryngectomy group demonstrated excellent communication ability both face-to-face and on the telephone. They exhibited superior scores for objective intelligibility, subjective intelligibility, acceptability, and intonation when compared with the total laryngopharyngectomy group. Both surgical groups produced similar amplitude and frequency parameters during normal conversation but had limited reserve when these functions were stressed. Despite these quantitative variations, patient acceptance was very high in both surgical groups. These results serve as a foundation for the evaluation and improvement of rehabilitation techniques.

Aged↗