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Biomedical subjects

M Davidian

Publications and source records attributed to M Davidian.

9 recordsLinked to original sources
PubMed1992

Smooth nonparametric maximum likelihood estimation for population pharmacokinetics, with application to quinidine.

The seminonparametric (SNP) method, popular in the econometrics literature, is proposed for use in population pharmacokinetic analysis. For data that can be described by the nonlinear mixed effects model, the method produces smooth nonparametric estimates of the entire random effects density and simultaneous estimates of fixed effects by maximum likelihood. A graphical model-building strategy based on the SNP method is described. The methods are illustrated by a population analysis of plasma levels in 136 patients undergoing oral quinidine therapy.

Absorption↗
PubMed1989

Electrocardiographic pseudo-myocardial infarct pattern in malignant cardiac disease.

A patient with disseminated diffuse histiocytic lymphoma had persistent electrocardiographic (ECG) signs of acute myocardial infarction without clinical, enzymatic, or hemodynamic evidence of myocardial necrosis. The ECG findings were felt to be secondary to myocardial tumor invasion by antemortem noninvasive testing. This was confirmed by postmortem examination. Based on this report and a literature review, the particular ECG findings noted (lateral leads) are felt to be highly predictive of direct tumor invasion in this setting.

Adult↗
PubMed1989

Gastrointestinal milk intolerance of infancy.

During a period of 30 months, cow's milk- or soy protein-induced colitis was diagnosed in 22 infants. All patients presented with hematochezia. Only three patients had substantial diarrhea. Colonoscopic evaluations demonstrated a characteristic mucosal appearance, manifested by aphthoid ulcerations with intervening, normal-appearing mucosa. Histologic findings included surface ulcerations and associated inflammation of the lamina propria and submucosa, marked by substantial eosinophilic infiltration. Both clinical symptoms and colonoscopic abnormalities rapidly resolved in all patients after the elimination of cow's milk and/or soy protein from the diet. These data indicate that hematochezia may be the predominant symptom of cow's milk protein and soy protein intolerance in many affected infants, and that colonoscopy is the most effective means of establishing a definitive diagnosis in this patient population.

Colitis↗
PubMed1988

Progesterone receptors in the human heart and great vessels.

Progesterone receptors (PgR) were identified in 31 of 50 specimens of human (men and women) thoracic ascending aorta, internal carotid, coronary artery, and left atrial appendage. This was accomplished with a peroxidase-antiperoxidase immunocytochemical assay employing a highly specific monoclonal antibody to primate PgR. In the aorta, specific staining was seen in the nuclei of smooth muscle cells and endothelium of intima, media, and adventitia. In the myocardium, staining was localized to the nuclei of the myocardial fibers. In internal carotid and coronary arteries, PgR was localized to endothelial nuclei of intima, and in vascular channels within the atherosclerotic plaques. PgR was also visible in the smooth muscle cell nuclei of uninvolved media and intima and at the plaque periphery. In contrast, receptor was not identified in vessels of the human uterus, breast, prostate, kidney, or gastrointestinal tract. These findings suggest that the heart and great vessels are target organs for steroid hormones.

Adult↗
PubMed1987

Life-threatening dysrhythmias in varicella myocarditis.

Varicella myocarditis is an unusual complication of a common childhood disease. Two patients with life-threatening dysrhythmias and circulatory failure are reported. One patient required permanent pacemaker implantation for acquired complete heart block, not previously described with varicella infection. Previously reported cases of varicella myocarditis are reviewed.

Arrhythmias, Cardiac↗
PubMed1979

Glucagonoma, chronic recurrent peptic ulcer disease, and enhanced amylase-creatinine clearance ratio. Report of a case with review of the literature.

A 53-year-old white woman developed diabetes mellitus, migratory erythema, and anemia, clinical features suggesting the presence of a "glucagonoma." Ten years earlier, after laparotomy and pancreatic biopsy, she had been told that she had an inoperable pancreatic carcinoma. Review of that biopsy together with current hormonal assay now confirms the diagnosis of glucagonoma. The recurrent peptic ulcer in this patient despite high levels of glucagon, a gastric inhibitory agent, is noted but not explained. An enhanced amylase-creatinine clearance ratio supports the notion that glucagon increases the clearances of amylase.

Adenoma, Islet Cell↗
PubMedDate not supplied

Intestinal duplication in a patient with neurofibromatosis: aid of ultrasound and CT scan in diagnosis.

A 5-year-old boy with neurofibromatosis is described, whose symptoms of abdominal pain and vomiting were due to an intestinal duplication. Intestinal duplication has not been previously reported as a cause of gastrointestinal symptoms in neurofibromatosis. The utilization of ultrasound and computerized tomography scan as useful modalities for the diagnosis of duplication of the bowel is described.

Child, Preschool↗
PubMedDate not supplied

Reduced cardiac selenium content in the acquired immunodeficiency syndrome.

Selenium deficiency has been implicated in the pathogenesis of a dilated congestive cardiomyopathy in areas of China (Keshan disease) and in several patients on long-term total parenteral nutrition. Recently a clinically and pathologically similar cardiomyopathy has been described in AIDS. Since blood selenium levels are low in AIDS, we assayed cardiac selenium status by a spectrofluorometric method in eight AIDS patients at autopsy compared to nine age-matched, non-AIDS autopsy controls with histologically normal hearts. We found (mean +/- SD) a cardiac selenium level of 0.327 +/- 0.082 microgram/g dry weight in AIDS vs 0.534 +/- 0.184 microgram/g dry weight in controls (p less than 0.01; Student's t test). There were no significant differences between the groups for heart weight, serum CPK, or other laboratory parameters. No specific chest x-ray or electrocardiographic abnormalities were present. Histologically, all AIDS hearts were abnormal; mostly with mild degrees of muscle hypertrophy or fibrosis. Foci of myocytolysis and myocyte necrosis and fibrous replacement of myocytes and monocytic infiltration were present in two AIDS cases. We conclude that heart tissue in AIDS demonstrates a significant selenium deficit. These data provide a potential link between selenium deficiency and cardiomyopathy in AIDS.

Acquired Immunodeficiency Syndrome↗