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Biomedical subjects

J S Stevens

Publications and source records attributed to J S Stevens.

At least 19 recordsLinked to original sources
PubMed2001

Usefulness of preoperative lymphoscintigraphy for the identification of sentinel lymph nodes in melanoma.

BACKGROUND: The exact role of lymphoscintigraphy (LS) in the evaluation of sentinel lymph nodes (SLNs) in melanoma is controversial. METHODS: We reviewed our experience with preoperative LS for the determination of the lymph node drainage pattern of clinically node negative primary melanomas, with attention to the rate of ambiguous drainage and the effect of previous wide local excision (WLE). RESULTS: The scans of 87 patients who underwent LS at our institution for evaluation of their primary melanomas from 1995 to the present were reviewed. Fourteen of the primary tumor sites were in the head and neck region, 41 were truncal, and 32 were in the extremities. The average tumor thickness was 2.6 mm. Nine of 14 (64%) head/neck lesions and 12 of 41 (29%) truncal lesions displayed ambiguous drainage, as compared with only 2 of 32 (6%) extremity lesions (P <0.05). Forty-one of the 87 patients (47%) had undergone previous WLE of their primary lesion prior to their LS. The number of draining basins for the WLE and the non-WLE groups were not significantly different, and at least one SLN was found for all WLE cases. CONCLUSIONS: Preoperative LS is important for the treatment planning of SLN biopsy for head/neck and truncal melanomas, but adds little additional information for extremity lesions. Lymph node drainage scans and subsequent SLN biopsies are not contraindicated in the presence of a prior WLE.

Adolescent↗
PubMed1996

MAG3 renal transplant tomography SPECT with a non-SPECT agent.

The authors encountered a renal transplant patient in whom tubular stasis permitted sufficient time to perform SPECT using Tc-99m MAG3. SPECT revealed a defect that was not apparent on the planar study. Renal biopsy showed acute vascular rejection. On a subsequent Tc-99m MAG3 SPECT study the defect had resolved.

Adult↗
PubMed1996

Alagille's syndrome. New manifestations.

The authors present the case of an infant with Alagille's syndrome who had cholestatic jaundice. The findings on IDA scintigraphy differed in several significant respects from previously reported cases. The hepatobiliary scintigraphic manifestations of Alagille's syndrome are more varied than previously thought.

Alagille Syndrome↗
PubMed1996

Renal transplant nuclear tomography using Tc-99m MAG3.

In this study, the authors performed SPECT imaging on 12 renal transplant patients immediately after a routine planar study demonstrated tubular stasis. The stasis allowed the authors to obtain good quality tomograms on all of them. In five patients, the findings on the planar and SPECT studies were identical. In five patients, there was decreased upper pole activity on planar images and SPECT imaging differentiated between attenuation (4 patients) and cortical thinning (1 patient). In the remaining two patients, the SPECT images showed unanticipated information. It is not yet clear if this new information is of clinical value. It was concluded that diagnostic quality nuclear tomograms in renal transplant patients with tubular stasis can be easily and consistently obtained.

Humans↗
PubMed1995

Gastric activity on dipyridamole 201Tl myocardial perfusion imaging: a clinically useful finding.

To determine the potential association of increased 201Tl uptake by the stomach with symptoms referable to gastritis, 39 consecutive patients experiencing chest pain syndromes underwent a routine dipyridamole 201Tl pharmacological stress test. With the patient in a fasting state, dipyridamole was infused intravenously (0.56 mg kg-1), shortly followed by 201Tl infusion and subsequent image acquisition for single photon emission tomography (SPET). The original 32 SPET images over 180 degrees of arc were interpreted without knowledge of clinical data, using a 4-point scoring system. Patients with active symptoms of gastro-oesophageal discomfort (n = 17) were found to have significantly greater 201Tl stomach uptake scores, compared to the little or no uptake in the 22 patients without such active symptoms (P = 0.0001). A stepwise logistic regression analysis was used to determine which factor(s) showed independent predictive value of 201Tl gastric uptake. The only two independent variables identified were the presence of active gastritis symptoms and the use of anti-gastritis medications. Elevated gastric 201Tl uptake may be a clinically useful finding indicative of gastric inflammation that may be of value in the differential diagnosis of chest and epigastric discomfort.

Aged↗
PubMed1991

Residual spleen found on denatured red blood cell scan following negative colloid scans.

The technetium-sulfur colloid liver-spleen examination is widely used to evaluate patients with idiopathic thrombocytopenic purpura for residual splenic tissue following splenectomy. Technetium-labeled heat-damaged red blood cell imaging is another sensitive test for residual splenic tissue. We recently encountered a patient with idiopathic thrombocytopenic purpura who was initially evaluated with a technetium sulfur colloid scan which was negative. A denatured red blood cell scan was subsequently performed which revealed intense focal activity in the region of the splenic bed. Surgery confirmed this to be splenic tissue. Our results emphasize the utility of the denatured red blood cell examination in the setting of strong clinical suspicion for residual splenic tissue following a negative sulfur colloid study.

Adult↗
PubMed1989

Control-related cognitions and depression among inpatient children and adolescents.

In previous studies, children with numerous depressive symptoms have shown two patterns of control-related cognition: (1) low levels of perceived personal competence, and (2) "contingency uncertainty"--confusion regarding the causes of significant events. The generality of these findings was tested for more seriously disturbed children. Three child inpatient samples, from separate psychiatric hospitals, completed the Children's Depression Inventory (CDI) plus measures of control-related beliefs. In all three samples, the findings resembled those of previous studies: CDI scores were significantly related to low perceived competence and to contingency uncertainty; by contrast, CDI scores were only weakly related to perceived noncontingency. The findings suggest that depressive symptoms in children may be (1) more closely linked to "personal helplessness" than to "universal helplessness," and (2) more closely linked to uncertainty about the causes of events than to firm beliefs in noncontingency. The findings carry implications for etiology and treatment of child depression.

Adolescent↗
PubMed1983

Extraction of a melanoma growth-stimulatory activity from culture medium conditioned by the Hs0294 human melanoma cell line.

Extracts of conditioned medium (CM) from Hs0294 human malignant melanoma cells stimulate [3H]thymidine incorporation and an increase in cell number in serum-depleted Hs0294 cells. This activity is acid and heat stable, nonproteolytic, protease sensitive, contains disulfide bonds and elutes broadly from a Bio-Gel P-30 column with an approximate molecular weight range of 6,000 to 25,000. Hs0294 CM also stimulates [3H]thymidine incorporation in nonmalignant human nevus cells and normal rat kidney fibroblast cells but not in human fibroblasts. There was only limited competition with 125I-epidermal growth factor in binding assays. Hs0294 CM extracts stimulate anchorage-independent growth in normal rat kidney fibroblast cells in soft agar but not in Hs0294 cells, nevus cells, or human fibroblasts. This second activity elutes from the Bio-Gel P-30 column in two positions with apparent molecular weights of 27,000 and 11,000.

Agar↗
PubMed1982

In vitro growth promotion in human malignant melanoma cells by fibroblast growth factor.

Bovine pituitary fibroblast growth factor (FGF) stimulates the incorporation of [3H]thymidine into DNA in serum-depleted cultures of some but not other human melanoma cells. The melanotic malignant melanoma cell line MIRW exhibited a 40% increase in [3H]thymidine incorporation into DNA and a 48% increase in cell number in response to 3.73 x 10(-9) M FGF. This same concentration of FGF produced a 22% increase in [3H]thymidine incorporation in the melanotic melanoma cell line Hs0294. However, FGF had no effect on the amelanotic melanoma cell line Hs0675, early-passage cultures of a human amelanotic melanoma (W-1), or early-passage cultures of a congenital nevus (N-1).

Cell Division↗
PubMed1981

Type A behavior, field dependence, and serum lipids.

Given evidence that individual differences on the cognitive style dimension of field dependence/independence are significantly related to sympathetically mediated cardiovascular functioning and lipid metabolism, a correlational study was designed to examine associations between Type A behavior, field dependence, and serum lipids. It was hypothesized that field dependent Type A individuals would exhibit higher levels of total cholesterol and triglycerides than would field independent Type A individuals. Using 82 medical students as subjects, the hypothesis was supported among both males and females for total cholesterol, with a trend in the predicted direction for triglycerides. Field dependent Type A individuals of both sexes were also found to have a higher level of low-density lipoprotein to total cholesterol, when compared to their field independent Type A counterparts. The overall pattern of findings provides suggestive evidence that field dependence is an important mediating personality factor influencing levels of autonomic arousal and coronary risk among Type A individuals. Alternative explanations as to why field dependent Type A individuals may be more chronically aroused in response to environmental stimuli are discussed.

Adult↗
PubMed1980

Piroxicam, a structurally novel anti-inflammatory compound. Mode of prostaglandin synthesis inhibition.

Piroxicam is a potent inhibitor of prostaglandin biosynthesis. Experiments utilizing cell culture and microsomes derived from various sources have demonstrated that piroxicam is a selective inhibitor of the cyclooxygenase step of arachidonic acid metabolism. Little blocking activity is observed at the phospholipase, thromboxane or prostacyclin synthetase, and arachidonic acid lipoxygenase steps.

Animals↗
PubMed1975

Abnormal radionuclide cerebral angiograms and scans due to seizures.

The effect of recent seizures on the brain scan was determined in a retrospective study of patients who had had seizures. All patients who underwent brain scanning within eight days of seizures and who did not have a specific intracranial lesion were included. The 99mTc-pertechnetate cerebral angiogram and/or delayed scan was abnormal in 73% of 22 patients. The data suggest that if seizures occur within six days of the brain imaging, the image is likely to be abnormal.

Adolescent↗