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Biomedical subjects

C Smith

Publications and source records attributed to C Smith.

At least 865 records · Page 48Linked to original sources
PubMed1986

Ventilatory responses to carbon dioxide in infants at risk for sudden infant death syndrome.

We examined the ventilatory response to inhaled CO2 in 77 infants at postconceptional ages ranging from 31 to 50 wk, 43 of whom were also evaluated with a 12-h pneumocardiogram (PCG). Infants were tested after sedation with chloral hydrate, and monitored with ECG and transcutaneous oxygen and CO2 monitors. Sleep state was evaluated by visual inspection of the infant's behavior. Among the 43 infants examined with the PCG, 22 had abnormal PCGs. Of these, 27% had significantly (p less than .05) abnormal CO2 response slopes, compared to 9% of those with normal PCGs. Breathing frequency did not change after CO2 inhalation in 82% of the abnormal PCG and in 33% of the normal PCG groups.

Apnea↗
PubMed1986

Objective responses to ketoconazole therapy in patients with relapsed progressive prostatic cancer.

The contribution of adrenal androgens to the maintenance and progression of so-called hormone-unresponsive prostatic carcinoma was studied in 20 patients with advanced relapsed disease. The role played by testicular androgens had been negated by prior orchiectomy or concurrent LHRH analogue therapy. Ketoconazole, an antifungal agent which inhibits adrenal and testicular androgenesis, administered in a dose of 400 mg 8-hourly, resulted in optimal suppression of adrenal androgens. The mean serum androstenedione concentration fell from 8.01 +/- 0.84 nMol/l to 1.55 +/- 0.25 nMol/l, P less than 0.001, and serum testosterone from 1.25 +/- 0.14 nMol/l to 0.36 +/- 0.06 nMol/l, P less than 0.01, after 6 months treatment. There was, however, no significant difference between patients receiving 400 and those receiving 200 mg. Androgen suppression resulted in six objective and ten subjective clinical responses. Ablation of both testicular and adrenal androgens can now be achieved using ketoconazole in combination with orchiectomy or LHRH analogues, but the high incidence of side effects may preclude its use in all patients with prostatic cancer. The results of this study support the concept of "total androgen ablation" as primary therapy in advanced prostatic cancer as a possible means of improving survival in this common malignancy.

Acid Phosphatase↗
PubMed1986

How to interpret coronary arteriograms.

Whether or not a radiologist is primarily responsible for coronary arteriography, the "compleat radiologist" will want to review this excellent primer on the subject.

Angiography↗
PubMed1986

Mycotic aneurysm of the thoracic aorta as a late complication of umbilical artery catheterization. A case report.

A case of mycotic thoracic pseudoaneurysm as a late complication of umbilical artery catheterization and septicaemia is presented. Thoracic pseudoaneurysm should be suspected when a child with mediastinal tumour has a history of neonatal umbilical artery catheterization complicated by septicaemia. The diagnosis should be established by CT-scanning, aortography or operation.

Aneurysm, Infected↗
PubMed1986

Blood flow in diethylstilbestrol-induced anterior pituitary gland hyperplasia.

Anterior pituitary hyperplasia was developed in female Fisher 344 rats by subcutaneously implanted slow-release diethylstilbestrol (DES) capsules. Blood flow was measured in two separate areas of the adenohypophysis using hydrogen clearance method at 6, 9, 10, and 13 weeks after the implantation. Blood flow progressively decreased while the DES capsules were in place (normal values in ml/g/min, mean +/- SD: 0.93 +/- .12 laterally and 1.15 +/- .11 medially, decreasing to 0.25 +/- .07 and 0.24 +/- .07, respectively, by 13 weeks). Histology confirmed nodular hyperplasia, development of large vascular lakes, and hemorrhages within the adenohypophysis. Total adenohypophysial blood flow was calculated as a product of mean blood flow as measured per unit weight and the weight of the gland. This figure progressively increased from 12.7 +/- 2 to 22.2 +/- 8 microliter/min by 13 weeks. All these changes were significant at the P less than 0.001 level. These blood flow measurements suggest that the hyperplastic adenohypophysis outgrows its blood supply which is additionally compromised by "useless" pooling of blood in the vascular lakes. However, there is an overall increase in the amount of blood flowing through the hyperplastic gland which may be explained by newly formed supplying vessels.

Animals↗
PubMed1986

Antigen-specific suppressor T cells prevent cardiac injury in Balb/c mice infected with a nonmyocarditic variant of coxsackievirus group B, type 3.

Two variants of coxsackievirus group B, Type 3 (CVB3o and CVB3M) infect Balb/c cardiac tissue equally, but only one variant (CVB3M) induces myocarditis. Various studies indicate that disease resistance in CVB3o-infected mice results from generation of suppressor cells. Low-dose cyclophosphamide (50 mg/kg body weight) treatment enhances inflammation in both CVB3M and CVB3o-infected animals, which clearly demonstrates that CVB3o has the capacity to induce disease, but inhibitory factors must exist preventing myocarditis. Spleen cells obtained from mice 10 days after CVB3o inoculation inhibited myocarditis induction in CVB3M-infected recipients, which confirms the presence of suppressor cells in these animals. The suppressor cell belongs to the Lyt 2+ subclass of T lymphocytes and specifically interferes with CVB3-induced myocarditis but fails to inhibit T-cell-mediated cardiac injury triggered by an unrelated virus, encephalomyocarditis virus.

Animals↗
PubMed1986

Coxsackievirus B-3 myocarditis. T-cell autoimmunity to heart antigens is resistant to cyclosporin-A treatment.

A cardiotropic variant of coxsackievirus group B, Type 3 (CVB3) induces myocarditis in inbred Balb/c mice. Myocardial injury is predominantly mediated by T lymphocytes recognizing normal myocyte antigens, making this an autoimmune disease. Nonetheless, the autoimmune response cannot be inhibited by cyclosporin A (CSA) treatment of the infected animals. Mortality in treated mice was increased 2-4 times, but neither virus-specific antibody or cytolytic T-lymphocyte responses were affected, and maximal virus concentrations in the hearts of CSA-treated and control animals were similar. Cardiac damage remains T-cell-mediated, because mice given both CSA and rabbit anti-thymocyte serum (ATS) failed to develop significant myocardial inflammation. CSA did suppress immunity in Balb/c mice to an allogeneic C57B1 lymphoma, EL4. Subcutaneous inoculation of mice with 2.5 X 10(6) ascites tumor cells resulted in 100% of the CSA-treated animals having tumors averaging 340 mg 10 days later, compared with less than 10% of control animals having tumors averaging only 30 mg. Humoral immunity to the tumor was absent in CSA-treated mice. Therefore, whether CSA induces immunosuppression depends upon the antigenic stimulus used.

Animals↗
PubMed1986

Tumors of the heart.

Two thirds of primary tumors of the heart are benign, and half of the benign tumors are myxomas. Metastatic tumors of the heart are 20 to 40 times more common than primary tumors. Metastatic tumors originate mainly in melanomas, leukemias/lymphomas, and carcinomas, especially of the lung or breast. The parts of the heart affected, in decreasing order of frequency, are the pericardium, myocardium, and endocardium. The clinical diagnosis is suggested by a patient with cancer and a normal heart who develops any kind of heart disease that is progressive and unresponsive to the usual methods of treatment. Irradiation, percardiocentesis, and injection with chemotherapeutic agents are effective in ameliorating symptoms from lymphomas/leukemias of the heart and in pericardial effusions due to malignant disease.

Carcinoma, Squamous Cell↗
PubMed1986

Estradiol receptors in human breast carcinomas assayed by use of monoclonal antibodies.

Our aim here was to compare a new enzyme immunoassay for estradiol receptors (ER) in breast cancer with a standard assay involving radiolabeled estradiol. A significant correlation was obtained between the standard binding assay and immunoassay (rs = 0.945, p less than 0.001, n = 100). Immunoreactive ER were also found in endometrial carcinomas but not in lung carcinomas, malignant melanomas, or basal cell carcinomas. Patients with breast cancers containing immunoreactive ER survived significantly longer after operation than patients whose tumor lacked immunoreactive ER. This immunoassay for ER is simpler than the binding assay and requires less time and tissue.

Antibodies, Monoclonal↗
PubMed1986

Discoid meniscus presenting as juvenile rheumatoid arthritis.

Discoid meniscus is a mechanical lesion described as having little inflammatory reaction. We describe a child with lateral discoid meniscus misdiagnosed as juvenile rheumatoid arthritis (JRA). Synovitis responded to aspirin, but function gradually deteriorated with increasing flexion deformity until arthrotomy and meniscectomy. Histology showed intense inflammatory changes compatible with JRA. Clinical and laboratory clues to early diagnosis were the localized nature of the inflammation on physical examination, radiographs and bone scan.

Arthritis, Juvenile↗
PubMed1986

A new model of tracheal stenosis and its repair with free periosteal grafts.

Stenosis of 50% to 80% of the cervical or thoracic tracheal lumen was created in 17 piglets by encircling the trachea with silicone rubber sheet for 3 to 19 days (median 14 days). In 13 animals thoracic tracheal stenosis was repaired by longitudinal incision and insertion of a free tibial periosteal graft into the defect. An omental pedicle graft was applied to the surface of the free periosteal graft to augment its blood supply in three of these animals. An endotracheal silicone rubber splint was left in place for 2 to 3 weeks after the operations. Four animals served as untreated controls. In 12 of 13 piglets respiratory obstruction was relieved. One repair failed because of graft necrosis. In two animals put to death 1 month and 2 months later, stenosis was absent and the grafts showed variable ossification. The luminal surface had epithelialized. In nine of 10 animals put to death 3 months after the operation, tracheal cross-sectional areas had doubled, stenosis and granulation tissue were absent, and all the grafts had ossified and epithelialized. A mild stenosis (24%) developed over a 2 mm length in one animal and the graft had not ossified. The omental pedicle graft did not improve vascularization of the free periosteal graft. These studies describe a model of tracheal stenosis that can be used to assess various methods of repair. The results indicate that tracheal stenosis can be successfully treated by incision and insertion of a free periosteal graft into the defect.

Animals↗
PubMed1985

Idiopathic hematuria of unilateral renal origin in a dog.

Idiopathic hematuria of unilateral renal origin was diagnosed in a 3-month-old male Weimaraner. The hematuria had been visible grossly for 6 weeks. Extensive clinicopathologic, radiographic, and histologic evaluations localized the source of the hematuria to the right kidney, but could not identify a cause. Nephrectomy of the right kidney resolved the problem. This case report supports a previous article comparing canine idiopathic hematuria of renal origin with benign essential hematuria of human beings.

Animals↗
PubMed1985

Steroid-responsive nephrotic syndrome: a generalised disorder of membrane negative charge.

A simple chemical test, based on the binding of the cationic dye alcian-blue 8GX (AB), has been devised to measure negative charge on cell membranes. The test has demonstrated that AB binding to red blood cells and platelets is significantly less in children with steroid-responsive nephrotic syndrome (SRNS) or nephrotic syndrome associated with focal segmental glomerulosclerosis than in normal controls. However, the sialic acid content of the nephrotic cell membrane is normal. This suggests that a generalised loss of membrane negative charge occurs in SRNS and that this is due to neutralisation rather than absence of anionic groups.

Adolescent↗
PubMed1985

Regulation of synthesis and activity of bovine adrenocortical NADPH-cytochrome P-450 reductase by ACTH.

Primary, monolayer cultures of bovine adrenocortical cells have been utilized to demonstrate that ACTH regulates the synthesis and thus the activity of NADPH-cytochrome P-450 reductase. The temporal pattern of induction correlates well with that previously reported for cytochromes P-45017 alpha and P-450 C21, microsomal steroid hydroxylases serviced by P-450 reductase. Results of in vitro translation studies suggest that ACTH regulates P-450 reductase synthesis at the transcriptional level and show that the adrenocortical enzyme is synthesized as the mature form. The action of ACTH to induce P-450 reductase synthesis in the adrenal cortex can be mimicked by dibutyryl cAMP, but not by phenobarbital which induces P-450 reductase synthesis in liver.

Adrenal Cortex↗