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Biomedical subjects

D E Stewart

Publications and source records attributed to D E Stewart.

At least 73 records · Page 4Linked to original sources
PubMed1993

Intracellular compartmentation of organic anions within renal cells.

Epifluorescence microscopy and video-image analysis were used to measure the distribution of the monovalent organic anion fluorescein (FL) within the cells of three organic anion-secreting renal epithelia: crab urinary bladder (a proximal tubule analogue), opossum kidney (OK) cells in culture, and intact teleost proximal tubules. In all three preparations the intracellular FL distribution was nonuniform. Two distinct intracellular compartments were detected, one being diffuse and cytoplasmic and the other punctate. With low FL concentrations in the medium (1 microM and below) dye accumulation in the punctate compartment exceeded that of the cytoplasm. In crab bladder epithelium FL uptake into both compartments was inhibited by external probenecid, p-aminohippurate (PAH), and LiCl and stimulated by 10-50 microM external glutarate, suggesting that the punctate compartment loaded by a two-step mechanism: transport into the cytoplasm at the basolateral membrane, followed by accumulation at specific intracellular sites. Experiments in which FL was microinjected into OK cells directly demonstrated movement of FL from the cytoplasmic to the punctate compartment. Accumulation in the latter was specific, i.e., inhibitable by coinjected PAH and probenecid, and energy dependent. Together, these findings indicate that during secretion organic anions are sequestered within renal cells. The role of sequestration in overall transport remains to be determined.

Animals↗
PubMed1993

Psychologic distress during menopause: associations across the reproductive life cycle.

OBJECTIVE: To determine if women with high psychologic distress attending a menopause clinic report more previous psychiatric disorders (especially depression), or psychologic distress associated with oral contraceptive use and reproductive cycle events than women with low psychologic distress attending the clinic. METHOD: Consecutive women attending a university hospital menopause clinic were administered the Brief Symptom Inventory (BSI). Women with high psychologic distress (who met case severity on the BSI general severity index) were compared to a similar number of the lowest scoring clinic women on their reports of previous psychiatric diagnoses and treatment, and depression or distress related to oral contraceptive use, the premenstrual period, or associated with pregnancy. RESULTS: The forty-four women with high psychologic distress were significantly more likely than the forty-two menopause clinic patients with low psychologic distress to report a past psychiatric diagnosis (usually depression) (p = 0.001), requiring anti-depressant treatment (p = 0.002), oral contraceptive dysphoria (p = 0.004), dysphoric premenstrual syndrome (p = 0.000), postnatal blues (p = 0.02) and postpartum depression (p = 0.004). CONCLUSIONS: Although the halo effect of current distress or retrospective reporting may have biased these results, the similarity of ratings in the two groups on physical symptoms in menopause and psychologic symptoms during pregnancy makes this less likely. These findings corroborate other recent studies showing that women who suffer from affective disorders following one reproductive event are more vulnerable to recurrences associated with others. Clinicians should inquire about possible relationships between previous depression or psychologic distress and reproductive cycle events as it may help predict women who are vulnerable to affective disorders and psychological distress at these critical times.

Adolescent↗
PubMed1993

The effect of educational brochures on knowledge and emotional distress in women with abnormal Papanicolaou smears.

OBJECTIVE: To determine whether an educational brochure about abnormal Papanicolaou smears could reduce psychological distress and concerns about cancer and future health, and increase knowledge about dysplasia and the investigation, treatment, and recommended follow-up. METHODS: One hundred twenty-five consecutive women with dysplasia on a Papanicolaou smear referred to a colposcopy clinic for their first examination were alternately assigned to receive a mailed educational brochure the same day or to receive no brochure. At the colposcopy clinic, consenting women were given the Brief Symptom Inventory, specific questions about feelings regarding an abnormal smear, and a knowledge quiz about dysplasia, colposcopy, and the recommended follow-up. RESULTS: Women who received the brochure were significantly less distressed on the Brief Symptom Inventory and were less anxious about the abnormal Papanicolaou smear, the fear of cancer, and their future health than were women not receiving the brochure. Study women also performed significantly better on knowledge questions about dysplasia, colposcopy, and the recommended follow-up. CONCLUSION: Given the low cost, ease of delivery, and usefulness of educational brochures in reducing psychological distress and increasing knowledge specific to the condition, an educational brochure should routinely accompany or immediately follow notification about an abnormal Papanicolaou smear.

Adult↗
PubMed1992

Obstructive jaundice associated with polysplenia syndrome in an older child.

Polysplenia syndrome includes malrotation and various forms of heterotaxy. Associated with this and malrotation are extrahepatic biliary anomalies. Actual obstruction, other than in associated biliary atresia, is extremely rare, and rarer still in older children. An 11-year-old girl presented with obstructive jaundice, malrotation, and heterotaxy, which were found in association with common bile duct anomalies and intermittent common bile duct obstruction. This case illustrates that the differential diagnosis of obstructive jaundice, even in older children, should include congenital anomalies, and that biliary anomalies should be considered in cases of malrotation and heterotaxy.

Abnormalities, Multiple↗
PubMed1992

High-fiber diet and serum tricyclic antidepressant levels.

The role of dietary fiber as a cause of antidepressant malabsorption has received little attention. Three patients are described who had previously been successfully treated with tricyclic antidepressants and subsequently became refractory to treatment after commencing a high-fiber diet. Serum antidepressant levels were decreased while the patients ingested the high-fiber diets and rose when the fiber content of the diet was reduced. Clinical improvement of their depression followed the concomitant rise in serum tricyclic antidepressant levels.

Adult↗
PubMed1992

A prospective study of the effectiveness of brief professionally-led support groups for infertility patients.

OBJECTIVE: This study prospectively evaluates the effectiveness and patient acceptability of professionally-led support groups in alleviating psychologic distress in infertility patients. METHOD: Sixty-four consecutive patients in a university hospital infertility program were administered a battery of psychologic tests before and after attendance at an 8 weekly session support group. The comparison group consisted of 35 consecutive infertility referrals to the same unit who were not initially offered the support group and were similarly tested over an 8 week period. RESULTS: Support group patients had significantly greater (p less than or equal to 0.01) entry than exit scores on several measures of psychologic distress and depression (the Beck Depression Inventory, the Hamilton Rating Scale for Depression, and the Global Severity Index, Anxiety, Depression, Hostility and Obsessive Compulsive Subscales of the Brief Symptom Inventory). The Avoidance Coping Style on the Moos Coping Responses Inventory was correlated with a higher Global Severity Index (p less than or equal to 0.01). Comparison group patients had similar psychometric scores to the support group patients at entry but showed no change over 8 weeks. Attenders expressed a high rate of satisfaction with the support group. CONCLUSIONS: Professionally-led support groups are a highly acceptable and effective intervention in self-referred patients in alleviating psychological distress related to infertility.

Adaptation, Psychological↗
PubMed1992

Psychologic distress during the menopausal years in women attending a menopause clinic.

OBJECTIVE: This study measures psychologic distress in women attending a menopause clinic to determine if significant differences exist between peri-menopausal and menopausal women. METHOD: Consecutive women attending a university hospital menopause clinic were administered the Brief Symptom Inventory (BSI) and a study questionnaire to determine menopausal symptoms, menstrual cycle status, and use of hormone replacement therapy (HRT). The BSI results were compared between menopausal and perimenopausal women, and to a normative sample of middle-aged women who were nonpatients. RESULTS: Two hundred and fifty-nine menopause clinic women completed the questionnaire: 113 perimenopausal and 146 menopausal women. There was significantly greater psychologic distress on the BSI among perimenopausal as compared to menopausal women on the global severity index, and each of the anxiety, hostility, somatization, depression, paranoid, and psychoticism subscales. Perimenopausal women met BSI caseness severity criteria significantly more often than did menopausal women on the global severity index, and on the subscales for depression, anxiety, and psychoticism. On the BSI, menopausal women showed results similar to those of a normative sample of nonpatient middle-aged women. CONCLUSIONS: Perimenopausal women attending menopause clinics have significantly higher levels of psychologic distress meeting case severity criteria on the BSI. Further research is warranted to define the subgroups of perimenopausal women who are at increased risk, in the hopes of developing effective interventions.

Adaptation, Psychological↗
PubMed1992

Reproductive functions in eating disorders.

This article reviews current knowledge about the effects of anorexia nervosa, bulimia nervosa and partial syndromes on ovulation, menstruation, sexuality, fertility, pregnancy and fetal-infant health. Eating disorders may result in failure to ovulate, oligomenorrhea, amenorrhea, reduced sex drive, infertility, hyperemesis gravidarum, low maternal weight gain in pregnancy, small babies for gestational date, low birth weight infants, increased neonatal morbidity and problems in infant feeding. The available information suggests that clinicians should inquire about nutritional intake, a history of eating disorders and weight reducing behaviours as part of the routine assessment of patients with the disorders of reproductive function listed above. If an eating disorder is discovered before conception, the woman should be encouraged to delay pregnancy until the eating disorder is treated and effectively under control. If the woman is pregnant, early diagnosis and treatment are essential to reduce maternal and fetal complications. The infants of eating-disordered women should be carefully followed to ensure adequate nutritional intake. Problems in reproductive function related to eating disorders offer rich opportunities for multispecialty collaboration in primary and secondary prevention programmes directed toward both mother and infant.

Anovulation↗
PubMed1992

Blunt trauma of the diaphragm: a 15-county, private hospital experience.

During a 6-year period, 52 patients with nonpenetrating trauma to the diaphragm were treated in eight acute care hospitals, serving a 15-county area of Michigan. Charts were reviewed to identify patterns of injury, treatment, and outcome. Preoperative diagnosis was made in 50 per cent of cases based on chest x-ray findings; the remainder were diagnosed intraoperatively. Clinical examination revealed respiratory distress, decreased breath sounds, or elevated hemidiaphragm in 81 per cent of patients. Forty-two per cent of patients sustained significant head injuries. Fractures were present in 75 per cent of patients. Major chest injury was found in 92 per cent. Intra-abdominal organs were herniated in 67 per cent of cases with the stomach being most common (54%). The spleen was the most commonly injured abdominal organ (60%). The left diaphragm was injured in 75 per cent of cases; 2 per cent were bilateral. The most common postoperative complication was pneumonia. Mortality in this series was 13 per cent, with no case being related to the diaphragmatic injury. The authors conclude that blunt injuries to the diaphragm in the multiply-injured patient present a clinical diagnostic challenge requiring a high index of suspicion. Optimal care requires a multi-disciplinary critical care team to manage the high incidence of associated central nervous system, orthopedic, and chest injuries and associated high mortality rates.

Adolescent↗
PubMed1991

Molecular dynamics simulations of the cytochrome c3-rubredoxin complex from Desulfovibrio vulgaris.

Molecular dynamics simulations have been carried out on the complex formed between the tetraheme cytochrome c3 and the iron protein rubredoxin from the sulfate-reducing bacterium Desulfovibrio vulgaris. These simulations were performed both with explicit solvent water molecules included, and without solvent molecules using a distance-dependent dielectric constant to approximate the screening effects of solvent. The results of both simulations are strikingly different, indicating that the representation of environmental effects is important in such simulations. For example, a striking adaptation of the two proteins seen in the nonsolvated simulation is not seen when explicit solvent water is included; in fact, the complex appears to become weaker in the solvated simulation. Nonetheless, the iron-iron distance decreases more significantly in the solvated simulation than in the nonsolvated simulation. It was found that in both cases molecular dynamics optimized the structures further than energy minimization alone.

Computer Simulation↗
PubMed1991

Plasma corticotrophin releasing factor and vasopressin responses to exercise in normal man.

OBJECTIVE: To evaluate the hypothalamo-pituitary-adrenal (HPA) response to both mild and intense exercise. DESIGN: Maximum oxygen consumption (VO2max.) was initially determined. Exercise to 20% (mild) and 90% (intense) VO2max. was undertaken in random order. Subjects were exercised over a 5-minute period to the required level of intensity, which was maintained for a further 10 minutes. SUBJECTS: Six trained male athletes. MEASUREMENTS: Brachial vein blood was sampled before and at 5-minute intervals during and after exercise and assayed for plasma cortisol, ACTH, arginine vasopressin (AVP), corticotrophin releasing factor (CRF), sodium and lactate levels. Haemoglobin and haematocrit were measured before and at the end of exercise. Heart rate was monitored continuously and blood pressure measured whenever blood was sampled before and after exercise. RESULTS: Maximum heart rate was 184 +/- 2 and 82 +/- 5 (mean +/- SEM) beats per minute at 90 and 20% VO2max. respectively. Plasma volume fell by 8.7 +/- 2.4% with intense exercise. Significant increases in plasma concentrations of AVP, ACTH and cortisol, but not CRF, occurred during intense exercise. Plasma sodium concentration, which increased during intense but not mild exercise, peaked at 10 minutes after the onset of exercise and preceded the rise in plasma AVP. The AVP peak clearly preceded the ACTH peak in two subjects and occurred synchronously with it in three subjects. CONCLUSION: These results indicate that although significant HPA activation occurs during intense exercise, CRF does not appear to play a major role in mediating the ACTH response to an acute episode of vigorous exercise in man. AVP may be more important in this regard.

Adrenocorticotropic Hormone↗
PubMed1991

A survey of Canadian psychiatric residents regarding resident-educator sexual contact.

BACKGROUND AND METHOD: A survey of all Canadian psychiatric residents was undertaken to ascertain the prevalence of resident-educator sexual contact in training programs, the residents' feelings about this contact, their knowledge of the ethical standards of the profession, and the extent of the information they had been given about this subject. An investigator-designed questionnaire was circulated to all psychiatric residents in Canada through the directors of postgraduate training programs. To ensure confidentiality, the residents returned their questionnaires directly to the investigators. RESULTS: Of the 314 respondents, 4.1% (N = 6) of the female residents and 1.2% (N = 2) of the male residents reported sexual involvements with their educators. Although the majority of these eight residents had positive or neutral feelings about the contact, 37.5% (N = 3) of the involved residents had mixed feelings. The residents' education concerning resident-educator sexual contact was strikingly sparse. CONCLUSIONS: This study highlights the need for inclusion of this tissue in residency programs.

Adult↗
PubMed1991

Prophylactic lithium in puerperal psychosis. The experience of three centres.

At three centres, 21 women at high risk for puerperal psychosis were given prophylactic lithium carbonate late in the third trimester of pregnancy or immediately after delivery. Only two of the women had a recurrence of their psychotic illness while on prophylactic lithium. One woman given lithium during third trimester had an unexplained stillbirth. Although a larger sample in a carefully controlled study is still required, there now seems to be grounds for the use of prophylactic lithium immediately after delivery in women not breastfeeding who have previously suffered from either puerperal psychosis or bipolar disorder.

Adolescent↗
PubMed1991

Drug interaction between rifampin and nortriptyline: a case report.

This case illustrates a pharmacokinetic interaction between the tricyclic antidepressant, nortriptyline, and the antituberculosis drug, rifampin. Higher than expected doses of nortriptyline were required to obtain a therapeutic drug level while the patient was receiving rifampin. Following the discontinuation of rifampin, the patient became drowsy and the serum nortriptyline levels rose precipitously into the toxic range. The authors suggest that patients receiving rifampin and nortriptyline, (or other psychotropic drugs) be monitored closely and that similar drug interactions be anticipated.

Depressive Disorder↗
PubMed1990

Occurrence and role of cis peptide bonds in protein structures.

It has been widely assumed that the occurrence of cis peptide bonds in proteins is quite rare due to unfavorable contacts between adjacent amino acid residues in this isomeric form. To investigate this assumption, the Brookhaven Protein Data Bank was examined for the occurrences of cis peptide bonds. Out of 31,005 amide bonds, only 17, or 0.05%, are cis, while 99 of the 1534 imide bonds (X-Pro), or 6.5%, are cis. These figures are considerably less than the distribution predicted on the basis of the potential energy difference between the cis and trans isomeric forms and experimental data on small peptides. It is not known whether the lower than expected occurrence of cis peptide bonds arises from constraints imposed by the protein environment, or from assumptions made in the solution of the X-ray crystal structures. However, when the occurrence of cis bonds in the data base is examined relative to the resolution of the structures, the number of cis bonds increases with increasing resolution. The distributions seen for these peptide omega bonds in the data base are not the same shape as the distributions predicted from simple potential energy barriers. They are sharper in the main, but they are also broader at the base with significant numbers of nonplanar peptide bonds. Cis peptide bonds are found primarily in bends and turns and, in the case of cis imide bonds (X-PRO), this correlation is so high that it suggests a specific role for cis imide groups in such structures.

Animals↗
PubMed1990

Infertility and eating disorders.

Sixty-six consecutive infertility clinic patients were prospectively screened with the 26-item Eating Attitudes Test and a study questionnaire. Women identified as being at high risk for an eating disorder were then interviewed to confirm or refute the diagnosis. A total of 7.6% of infertility clinic women were found to suffer from anorexia nervosa or bulimia nervosa. If eating disorders not otherwise specified were included, a total of 16.7% of infertility patients were found to suffer from an eating disorder. Among infertile women with amenorrhea or oligomenorrhea 58% had eating disorders. Because women often fail to disclose eating disorders to their gynecologists and may appear to be of normal weight, it is recommended that a nutritional and eating disorder history be taken in infertility patients, particularly those with menstrual abnormalities. It has previously been shown that disorder eating and nutrition can affect menstruation, fertility, maternal weight gain, and fetal well-being.

Adult↗