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Biomedical subjects

D Stewart

Publications and source records attributed to D Stewart.

At least 307 records · Page 17Linked to original sources
PubMed1985

Gastric acid secretory function in preterm infants.

To establish normal values for gastric secretory function in preterm infants, we studied 34 healthy preterm infants once a week during hospitalization. Basal acid output, pentagastrin-stimulated acid output, fasting serum gastrin, and fasting serum pancreatic polypeptide were measured during each study. Basal acid output at 1 week of age was 12 mumol/kg/hr, increasing over the first 4 weeks to 30 mumol/kg/hr. Administration of pentagastrin 6 micrograms/kg subcutaneously increased acid output in all age groups. Pentagastrin-stimulated acid output at 1 week was 21 mumol/kg/hr, increasing over the first 4 weeks to 44 mumol/kg/hr. Acid secretion did not change significantly over the next 4 to 6 weeks. Fasting serum gastrin concentration was stable over the first 6 weeks of life, but doubled during the end of the second month. Pancreatic polypeptide was found at low levels throughout the study. These studies confirm that the majority of healthy preterm infants secrete acid in quantity sufficient to maintain the gastric pH less than or equal to 4, providing a barrier to bacteria and protein antigens.

Achlorhydria↗
PubMed1985

Effect of physician dress style on patient-physician relationship.

This study evaluates the effect of physician dress and other variables (i.e., sex of physician and patient, age, and type and site of visit) on patient-physician rapport. Three hundred eighty-six teens filled out a questionnaire, at the end of an office visit, which evaluated their attitudes regarding their physician and their preference for physician dress. The physicians alternated between very informal, informal, formal-white coat, and formal-suit/dress styles. Dress style made no statistical difference in patients' attitudes toward their physician. When asked what they preferred their doctor to wear 43% responded "makes no difference," 26% said "white coat," 14% said "pants and shirt," 10% said "jeans and shirt," and 4% said "suit and tie." Female patients were significantly more comfortable (3.6 versus 3.3, p less than 0.01) with female physicians. Male patients did not show a preference for a same-sex physician.

Adolescent↗
PubMed1984

Bipolar oesophageal electrocardiography and pacing in a coronary care unit.

This paper describes our experience with bipolar oesophageal electrocardiography in a coronary care unit. Twenty-two patients with tachycardia were studied to clarify the nature of their tachycardia. The treatment of supraventricular tachycardia by rapid atrial pacing via the same electrode was assessed in eight patients. The equipment required and diagnostic and therapeutic applications of oesophageal electrocardiography in this setting are discussed.

Acute Disease↗
PubMed1984

Adrenergic innervation of the developing chick heart: neural crest ablations to produce sympathetically aneural hearts.

Ablation of various regions of premigratory trunk neural crest which gives rise to the sympathetic trunks was used to remove sympathetic cardiac innervation. Neuronal uptake of [3H]-norepinephrine was used as an index of neuronal development in the chick atrium. Following ablation of neural crest over somites 10-15 or 15-20, uptake was significantly decreased in the atrium at 16 and 17 days of development. Ablation of neural crest over somites 5-10 and 20-25 caused no decrease in [3H]-norepinephrine uptake. Removal of neural crest over somites 5-25 or 10-20 caused approximately equal depletions of [3H]-norepinephrine uptake in the atrium. Cardiac norepinephrine concentration was significantly depressed following ablation of neural crest over somites 5-25 but not over somites 10-20. Light-microscopic and histofluorescent preparations confirmed the absence of sympathetic trunks in the region of the normal origin of the sympathetic cardiac nerves following neural crest ablation over somites 10-20. The neural tube and dorsal root ganglia were damaged in the area of the neural-crest ablation; however, all of these structures were normal cranial and caudal to the lesioned area. Development of most of the embryos as well as the morphology of all of the hearts was normal following the lesion. These results indicate that it is possible to produce sympathetically aneural hearts by neural-crest ablation; however, sympathetic cardiac nerves account for an insignificant amount of cardiac norepinephrine. The adrenal medulla is the most likely source of cardiac norepinephrine in sympathetically aneural hearts.

Animals↗
PubMed1984

PPD-induced monocyte chemotactic factor production by human milk cells.

The functional capability of antigen-stimulated breast milk cells to produce an immunologic mediator was examined. Colostrum and comparison peripheral blood samples were obtained from ten women, two to four days postpartum, and supernatants from PPD-stimulated mononuclear cell cultures were assayed for the lymphokine, monocyte chemotactic factor. Five of the ten women studied had a history of a positive tuberculin skin test and one had received BCG immunization. Peripheral blood lymphocyte cultures and colostrum cell cultures from four of these six women produced monocyte chemotactic factor. These results demonstrated the functional capability of antigen-stimulated colostral cells to produce immunologic mediators.

BCG Vaccine↗
PubMed1984

Norepinephrine-stimulated vascular prostacyclin synthesis. Receptor-dependent calcium channels control prostaglandin synthesis.

Norepinephrine-stimulated prostacyclin synthesis was studied in rat aortic rings by measuring 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) by radioimmunoassay. Norepinephrine (10(-6) M) results in a 10- to 20-fold increase in 6-keto-PGF1 alpha synthesis by rat aortic rings (54 +/- 11 to 437 +/- 260 pg X mg wet weight-1 X 20 min-1). The maximal stimulation of 6-keto-PGF1 alpha synthesis was observed with a norepinephrine concentration of 10(-5) M at a mean effective concentration (EC50) of 9.5 +/- 3.2 X 10(-7) M which is similar to the contractile response (Emax = 10(-5) M, EC50 = 6.5 +/- 1.8 X 10(-7) M). Potassium chloride (30 mM), although causing a similar maximal contractile response as 10(-6) M norepinephrine, did not increase 6-keto-PGF1 alpha synthesis. Norepinephrine-stimulated 6-keto-PGF1 alpha synthesis was dependent upon extracellular calcium. Norepinephrine stimulation in Ca2+-free medium did not lead to a significant increase in 6-keto-PGF1 alpha synthesis. However, on the introduction of Ca2+, 6-keto-PGF1 alpha synthesis was restored to its initial level. Phentolamine (10(-6) M) (an alpha-adrenergic antagonist) and trifluroperazine (2.5 X 10(-4) M) (a calmodulin inhibitor) completely inhibited norepinephrine-stimulated 6-keto-PGF1 alpha synthesis, whereas verapamil 3 X 10(-6) M (a calcium channel blocking drug) only partially inhibited synthesis (control, 74 +/- 12; norepinephrine, 437 +/- 260; norepinephrine + verapamil, 123 +/- 8 pg X mg wet weight-1 X 20 min-1).(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Psychiatric assessment of competency to care for a new-born.

General hospital consultation psychiatrists are sometimes asked to assess the ability of a recently delivered mother to safely care for her new-born at home. There are surprisingly few papers in the literature that deal with this problem. The authors review their experience with 56 women referred by a maternity unit over a 10 year period and discuss the demographic characteristics, diagnosis, management, and outcome of their intervention. They discuss how such an assessment should be carried out and review the literature. Some conclusions are drawn about high risk factors, and the need for early identification of these mother-infant pairs as part of primary prevention. They point out the need to take decisive action when the infant's safety appears to be seriously at risk and note that the mothers and infants in their group have done fairly well during the follow-up period with appropriate treatment, teaching and supervision.

Child Abuse↗
PubMed1983

Intracerebral penetration and tissue distribution of 2,5-diaziridinyl 3,6-bis(carboethoxyamino) 1,4-benzoquinone (AZQ, NSC-182986).

[14C]AZQ (2-4 mg/m2, 100-200 mCi) was administered at varying times to five patients undergoing surgical resection of intracerebral tumors. Plasma, cerebrospinal fluid (CSF), edematous brain, and tumor specimens were obtained during surgery and the concentration of AZQ was determined radiochemically and chromatographically. Total [14C]AZQ equivalent concentration in tumor for two patients was determined to be 47.5% and 85% of concurrent plasma concentration which was similar to that found in normal brain (60.4% and 75.5% respectively). Only 18-45% of the total radioactivity in tumor tissue and 30-56% in plasma were accounted for by unchanged AZQ. These findings suggest that AZQ may be metabolized to a certain extent. Tissue samples from various organs were obtained during autopsy in a patient who expired ten days after AZQ administration. The highest AZQ concentration was found in the liver, followed by the kidney. Comparable amounts were found in normal brain and brain tumor (22 ng/g vs. 31 ng/g respectively). These results indicate that AZQ penetrates readily into the normal brain and brain tumor with a tendency to persist.

Adult↗
PubMed1983

Menstrual dysfunction in cystic fibrosis.

Several factors potentially involved in the menstrual dysfunction of some females with cystic fibrosis were analyzed by a retrospective chart review. The mean age of menarche for the cystic fibrosis patients was 14.4 years, compared to 12.9 years for American females (p less than 0.001). At last evaluation, comparison of the mean figures for amenorrheic patients and for menarchal cystic fibrosis patients reveals statistically significant differences in the age of diagnosis, weight-height index, weight, height, percent of body fat, weight percentile, and height percentile. The highest correlative was weight (r = 0.59). Of our cystic fibrosis patients who were menarchal, 95% had a weight greater than 82 pounds, whereas 75% of those who were amenorrheic weighed less than 82 pounds. Menstrual irregularities, sexual activity, and contraceptive use among these patients also is discussed.

Adolescent↗
PubMed1983

Postinfarction angina: results of early revascularization.

To assess the efficacy of surgical revascularization for postinfarction angina within 30 days of acute infarction, the clinical course of 103 patients treated surgically from January 1979 to July 1982 was reviewed. There were 84 men (82%) and 19 women (18%) with a mean age of 58 years (range 34 to 80). Group A (11 patients) underwent surgery within 24 hours of infarction, Group B (21 patients) within 7 days and Group C (71 patients) within 30 days. Eighty-four patients (82%) had subendocardial infarctions and 19 patients (18%) had transmural infarction. Transmural infarction was more common in patients in Group A (36%) than in those in either Group B (19%) or Group C (15%). There were two deaths, both in Group C (1.9%), within 30 days of surgery. The use of intraaortic balloon or inotropic support and the occurrence of major arrhythmias or perioperative infarction was noted in 30 patients (29%) (64% in Group A, 33% in Group B and 18% in Group C). The average time in the intensive care unit was 3.2 days, with an average total hospital stay after surgery of 8.3 days. Late follow-up (mean 15.4 months, range 1 to 39) is complete for 97 patients (97%). There were no late myocardial infarctions and 93 patients (96%) were essentially free of angina. The only late death (1.0%) was caused by septicemia from delayed sternal wound infection. This study suggests that myocardial revascularization within the first 30 days after myocardial infarction can be accomplished with an acceptable operative mortality in selected patients with postinfarction angina refractory to medical management.

Adult↗
PubMed1983

Curanderismo in Taos County, New Mexico--a possible case of anthropological romanticism?

Interviews with 25 Spanish-Americans of Taos County, New Mexico, indicate that time and acculturation have greatly eroded the belief in and practice of curanderismo, the traditional folk medical system of the Southwest. Curanderismo in northern New Mexico today has moved from being a primary and important source of medical care to one used alternatively and very occasionally in cases of pediatric disorders, chronic illnesses and pain, and for those maladies still classified according to the traditional folk beliefs.

Acculturation↗
PubMed1982

Antibody-dependent cell-mediated cytotoxicity in human cancer: characterization of patient leukocyte activity and treatment effects.

Antibody-dependent cell-mediated cytotoxicity (ADCC), medicated by peripheral blood Hypaque-Ficoll separated mononuclear cells, was studied in humans using chicken erythrocytes (CRBC) incubated in a 1:1200 dilution of rabbit anti-CRBC and human B erythrocytes (HRBC) incubation in a 1:20 dilution of isoantibody. At the optimal target effector ratio of 3:1, ADCC to both CRBC and HRBC was significantly higher than normal in 27 lung cancer, 18 malignant melanoma, and seven colon cancer patients, but not in 20 breast cancer patients. Chemotherapy (single-agent or combination) in 12 patients did not effect ADCC in vitro but significantly suppressed ADCC to both targets after only four or five days of therapy in vivo (ADCC to CRBC, 47.4 to 24.1% lysis: ADCC to HRBC, 48.1 to 16.3% lysis). Immunotherapy with intravenous (IV) corynebacterium parvum or IV methanol extraction residue of BCG (MER) boosted ADCC to both targets within four to seven days of the first dose. It was found that ADCC to HRBC but not to CRBC was completely absent in three cases of active hairy cell leukemia but was present in two cases in remission. The ADCC to HRBC showed an age-dependent increase in both the 51 normal subject and the cancer patients. This was not observed for ADCC to CRBC. The ADCC to CRBC was mediated mainly by an Fc-receptor-positive, nonadherent, small lymphocyte, and ADCC to HRBC was mediated entirely by an adherent monocyte. The ADCC did not correlate significantly with the H3 thymidine incorporation of peripheral blood mononuclear cells, cultured without stimulation for either one or seven days. It also did not correlate with the number of residual granulocytes in the mononuclear cell suspensions. Measurement of ADCC is a useful method of characterizing host defense in malignant disease and its modification by therapy.

Age Factors↗
PubMed1982

Changing treatment of pediatric splenic trauma.

A review of splenic injuries at Cincinnati Children's Hospital Medical Center from July 1978 to June 1980 revealed this form of injury in 29 patients. Treatment without surgery was successful in 21 patients. Seven patients required operation. One patient died shortly after admission of severe associated injuries. All patients admitted with blunt abdominal trauma were initially treated conservatively. If the clinical state improved, after transfusions if necessary, or remained stable and there were no objective signs of further blood loss, conservative therapy was continued. Liver-spleen scans were obtained on an urgent basis to confirm the diagnosis of splenic injury in patients who did not undergo surgery. No complications of treatment without surgery were recognized. The satisfactory outcome in these patients suggests that there is a place for treatment without surgery in some children with splenic injury.

Abdominal Injuries↗
PubMed1982

Phase II trail of PCNU in refractory advanced breast cancer.

An evaluation of PCNU was carried out in 28 patients with extensively treated refractory breast cancer. The starting dose was 60 mg/m2 in 13 patients and 90 mg/m2 in 15 patients given intravenously every 6 weeks. The major side effect was myelosuppression, manifested mainly as thrombocytopenia. Nonhematologic side effects were minimal, consisting mainly of transient nausea. One mixed response was seen. Four patients had stable disease. PCNU demonstrated limited activity in advanced breast cancer and was not effective in the treatment of central nervous system metastases.

Adenocarcinoma↗