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Biomedical subjects

A Stone

Publications and source records attributed to A Stone.

At least 37 records · Page 2Linked to original sources
PubMed1997

Symptomatic improvement of premenstrual dysphoric disorder with sertraline treatment. A randomized controlled trial. Sertraline Premenstrual Dysphoric Collaborative Study Group.

CONTEXT: Premenstrual dysphoric disorder is an important cause of symptoms and functional impairment in menstruating women. OBJECTIVE: To evaluate the efficacy of sertraline hydrochloride for treatment of premenstrual dysphoria by measuring changes in symptom expression and functional impairment. DESIGN: Two screening cycles followed by 1 single-blind placebo cycle and 3 cycles of randomized, double-blind, placebo treatment. SETTING: Twelve university-affiliated outpatient psychiatry and gynecology clinics. PATIENTS: Of the 447 women who requested participation, 243 met criteria for premenstrual dysphoric disorder and were randomized; 200 women completed the study. INTERVENTION: A flexible (50-150 mg) daily dose of sertraline hydrochloride. MAIN OUTCOME MEASURES: The Daily Record of Severity of Problems, Hamilton Rating Scale for Depression, Clinical Global Impression Scale, and Social Adjustment Scale. RESULTS: Mean (+/-SD) total daily symptom scores decreased significantly (P<.001) in the sertraline-treated (64+/-22 to 44+/-19) compared with the placebo-treated (62+/-22 to 54+/-24) groups. Significant improvement (P<.05) was found for all clinically derived symptom clusters (depressive, physical, and anger/irritability symptoms). Hamilton Rating Scale for Depression scores decreased by 44% and 29% in the sertraline and placebo groups, respectively (P<.002). End-point global ratings showed much or very much improvement in 62% of the active treatment group and 34% of the placebo treatment group (P<.001). Reported functional impairment was substantial at baseline. Improvement in psychosocial functioning with treatment was similar to what is found in studies of major depression. CONCLUSIONS: Sertraline was significantly better than placebo for treatment of premenstrual dysphoria as reflected by symptomatic improvement and change in reported functional impairment. Serotonin reuptake inhibitors such as sertraline are useful therapeutic options for women with premenstrual dysphoria.

1-Naphthylamine↗
PubMed1997

Neandertal DNA sequences and the origin of modern humans.

DNA was extracted from the Neandertal-type specimen found in 1856 in western Germany. By sequencing clones from short overlapping PCR products, a hitherto unknown mitochondrial (mt) DNA sequence was determined. Multiple controls indicate that this sequence is endogenous to the fossil. Sequence comparisons with human mtDNA sequences, as well as phylogenetic analyses, show that the Neandertal sequence falls outside the variation of modern humans. Furthermore, the age of the common ancestor of the Neandertal and modern human mtDNAs is estimated to be four times greater than that of the common ancestor of human mtDNAs. This suggests that Neandertals went extinct without contributing mtDNA to modern humans.

Animals↗
PubMed1997

Oxidative stress in diabetic macrovascular disease: does homocysteine play a role?

BACKGROUND: Non-insulin-dependent diabetes mellitus (NIDDM) and hyperhomocysteinemia are both associated with increased lipid peroxidation (oxidative stress). This may contribute to the accelerated vascular disease associated with these conditions. It is not known whether the coexistence of elevated homocysteine levels will stimulate oxidative stress further than that caused by diabetes alone. METHODS: Plasma concentrations of thiobarbituric acid reactive substances (TBARS), an index of lipid peroxidation, were measured in patients with NIDDM who had previously had a methionine load test; some of the patients had hyperhomocysteinemia. RESULTS: Plasma TBARS concentrations were elevated in diabetics with vascular disease. The additional presence of hyperhomocysteinemia was not associated with a further increase in plasma TBARS concentrations. CONCLUSIONS: Lipid peroxidation is increased in patients with diabetes mellitus and macrovascular disease and is not further elevated by the coexistence of elevated homocysteine levels. It is possible that diabetes maximally stimulates oxidative stress and any further acceleration of vascular disease in patients who have coexistent hyperhomocysteinemia is mediated through mechanisms other than lipid peroxidation.

Adult↗
PubMed1997

The mitogenic effect of KGF and the expression of its cell surface receptor on cultured normal and malignant human oral keratinocytes and on contiguous fibroblasts.

This study examined the mitogenic response to keratinocyte growth factor (KGF) of normal and tumour-derived human oral keratinocytes in which the degree of cellular differentiation was known and in contiguous fibroblast cultures derived from the malignant epithelial cultures. Keratinocytes, but not fibroblasts, were stimulated by KGF, thereby demonstrating epithelial target cell specificity of the ligand. KGF-induced stimulation of the tumour-derived keratinocytes cultured in the absence of the 3T3 fibroblast support broadly correlated with the degree of cellular differentiation; well-differentiated keratinocytes were stimulated more by KGF than their less differentiated counterparts. Malignant oral keratinocytes expressed KGF cell surface receptors (KD 451-709 pM; receptors/cell 2306-13645), but KGF receptor mRNA did not correlate with either KGF-induced mitogenesis or the degree of epithelial cell differentiation. When the tumour-derived keratinocytes were cultured in the presence of 3T3 fibroblasts, the mitogenic response to KGF was comparable to normal epithelial cells. The results suggest that KGF-mediated growth stimulation may not be significant in providing a selective advantage for the growth of malignant keratinocytes.

3T3 Cells↗
PubMed1997

Differential nitric oxide production by microvascular and macrovascular endothelial cells.

Phenotypic heterogeneity among endothelial cell populations may account for important organ-specific behaviors. Experimental evidence suggests that endothelium-derived nitric oxide mediates certain of these unique responses. The purpose of these investigations was to compare rat pulmonary microvascular endothelial cells with pulmonary artery and aortic macrovascular endothelial cells in their ability to generate nitric oxide (NO). Cultures of these microvascular and macrovascular endothelial cells were incubated with interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and Salmonella typhimurium lipopolysaccharide (LPS) alone or in combination, and nitrite production was measured. Single-agent exposure with IFN-gamma (up to 1,000 U/ml), TNF-alpha (up to 60,000 U/ml), or LPS (up to 500 ng/ml) had little effect on nitrite generation. Nitrite production by rat aortic macrovascular endothelial cells (RAEC) was significantly greater than that by the rat lung microvascular endothelial cells (RLMVEC) when stimulated with TNF-alpha + IFN-gamma, LPS + IFN-gamma, or TNF-alpha + LPS. The maximal response by all endothelial cell types (approximately 15-fold increase in RAEC and 8-fold increase in RLMVEC) was observed with LPS + IFN-gamma. The nitrite generation from rat pulmonary artery endothelial cells was intermediate between RAEC and RLMVEC responses when stimulated with IFN-gamma + LPS or TNF-alpha. Similar patterns of heterogeneous inducible nitric oxide synthase mRNA induction occurred when Northern analysis of specimens from the cultured endothelial cell types was done. These data suggest that phenotypic heterogeneity between these endothelial cell populations is substantial and, by inference, that site-specific NO. generation may occur.

Animals↗
PubMed1997

A preliminary study on the efficacy of sertraline and imipramine on anger attacks in atypical depression and dysthymia.

There is clinical and biological evidence suggesting that patients with anger attacks, sudden spells of anger accompanied by intense autonomic activation, may represent a distinct psychopathological subgroup of patients with depressive disorders. We compared the prevalence of anger attacks in 168 outpatients with atypical depression or primary dysthymia with 38 normal subjects and tested the effect of treatment on anger attacks in a double-blind, placebo-controlled trial of sertraline versus imipramine. Patients were randomly assigned to sertraline (n = 56), imipramine (n = 52), or placebo (n = 60) and were administered the Anger Attacks Questionnaire before and after treatment. Depressed outpatients were significantly more likely to report anger attacks than controls. Anger attacks ceased in 53 percent of the patients receiving sertraline, 57 percent of those receiving imipramine, and 37 percent of those in the placebo group. Our findings support previous studies indicating that anger attacks are more prevalent among depressed outpatients than normals. Our results also suggest that sertraline and imipramine may be more effective than placebo in reducing the number of anger attacks following treatment although the differences were not statistically significant. Larger studies are needed to confirm our findings.

1-Naphthylamine↗
PubMed1996

Hyperhomocysteinemia following a methionine load in patients with non-insulin-dependent diabetes mellitus and macrovascular disease.

In the setting of an outpatient diabetic clinic, we determined whether macrovascular disease in patients with diabetes mellitus is associated with hyperhomocysteinemia (elevated plasma homocysteine [H(e)] concentrations) following a methionine load. Methionine-load tests were performed in 18 healthy controls, 11 diabetics without vascular disease (five insulin-dependent [IDDM] and six non-insulin-dependent [NIDDM]); and 17 diabetics with vascular disease (five IDDM and 12 NIDDM). All subjects were male, and there was no significant difference in mean age among the three groups. We measured plasma H(e) concentrations before and 2, 4, 6, 8, and 24 hours after an oral methionine load. Hyperhomocysteinemia (peak plasma H(e) concentration > control mean +/- 2 SD) occurred with significantly greater frequency (seven of 18, 39%) in patients with NIDDM as compared with age-matched controls (7%), being more common in those with macrovascular disease (five of 12, 41%). The area under the curve (AUC) over 24 hours, reflecting the total period of exposure to H(e), was also elevated with greater frequency in patients with NIDDM and macrovascular disease (33%) as compared with controls (0%). We conclude that hyperhomocysteinemia is associated with macrovascular disease in a significant proportion of patients with NIDDM. Further investigation of this association may determine whether hyperhomocysteinemia contributes to the increased frequency and accelerated clinical course of vascular disease in patients with diabetes mellitus.

Administration, Oral↗
PubMed1996

Dysregulation of autocrine TGF-beta isoform production and ligand responses in human tumour-derived and Ha-ras-transfected keratinocytes and fibroblasts.

This study examined the autocrine production of TGF-beta 1, -beta 2 and -beta 3 in culture supernatants from tumour-derived (H series, n = 7; BICR series, n = 5), Ha-ras-transfected (n = 4) and normal (n = 2) human keratinocytes using a sandwich enzyme-linked immunosorbent assay (ELISA). Detection limits were 39.0 pg ml-1 for TGF-beta 1, 78.0 pg ml-1 for TGF-beta 2 and 1.9 ng ml-1 for TGF-beta 3. Tumour-derived oral keratinocytes predominantly produced less TGF-beta 1 than normal oral epithelial cells; the expression of endogenous TGF-beta 2 was variable. In keratinocytes containing mutant Ha-ras, TGF-beta 1 production was enhanced and TGF-beta 2 was undetectable. TGF-beta 3 mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR) but the protein was not detected in conditioned media, most probably because of the low detection limits of the ELISA for this isoform. Neutralisation experiments indicated that the latent TGF-beta peptide was secreted in keratinocyte conditioned medium. Seven tumour-derived keratinocyte cell lines (H series) and fibroblasts separated from normal (n = 1) and tumour-derived (n = 2) keratinocyte cultures were examined for their response to exogenous TGF-beta 1, -beta 2 and -beta 3. Six of seven tumour-derived keratinocyte cell lines were inhibited by TGF-beta 1 and TGF-beta 2 (-beta 1 > -beta 2); one cell line was refractory to both TGF-beta 1 and TGF-beta 2. Keratinocytes were inhibited (4 of 7), stimulated (1 of 7) or failed to respond (2 of 7) to TGF-beta 3, TGF-beta 1, -beta 2 and -beta 3 stimulated both normal and tumour-associated fibroblasts, but the tumour-associated fibroblasts showed less response to the ligands than their normal counterparts following prolonged treatment with each isoform. The results demonstrate variable autocrine production of TGF-beta isoforms by malignant keratinocytes, with loss of TGF-beta 1 generally associated with the tumour-derived phenotype and modification of endogenous isoform production dependent on the genetic background of the tumour cells. Further, the variable response of the tumour-derived keratinocytes and contiguous fibroblasts to the TGF-beta isoforms suggests that dysregulation of TGF-beta autocrine and paracrine networks are common characteristics of squamous epithelial malignancy.

Cell Line↗
PubMed1996

A professional practice model: two key components.

Professional practice models provide decentralized approaches to nursing practice. The components of such a model should include a primary nursing delivery system, decentralized decision making, salary compensation, self-scheduling and quality circles. This article describes two of the key components of the model--salaried compensation and self-scheduling--on a unit in one agency.

Decision Making, Organizational↗