Biomedical subjects

D Swartz

Publications and source records attributed to D Swartz.

At least 37 records · Page 2Linked to original sources

PubMed1997

What's hot and what's not anticipating trends in technology.

Technology tends to progress over time in a step fashion. Changes in productivity associated with technology, when followed over time, often plot out as an S curve. Long quiescent periods are interrupted by rapid rises in technology advance and productivity. Anticipating this is important since it often enables us to plan for new technology. The lag in response to change often leads to bad planning or bad decisions. For example, I recently brought a new 166 Mhz laptop just a month before the new 233s came out, with a corresponding drop in the price of the 166 models ... so it clear I am not omniscient on the subject. In this column we will discuss important trends and identify what is hot and what is not in order to help you anticipate change in technology. I'll explore eight areas in depth. I will also touch on what you need to do to take advantage of the new technology if you have invested in older legacy technology.

Computer Communication Networks↗

PubMed1996

Parathyroid hormone regulates the expression of rat osteoblast and osteosarcoma nuclear matrix proteins.

Parathyroid hormone (PTH) alters osteoblast morphology. How these changes in cell shape modify nuclear structure and ultimately gene expression is not known. Chronic exposure to rat PTH (1-34) [10 nM] attenuated the expression of 200, 190, and 160 kD proteins in the nuclear matrix-intermediate filament subfraction of the rat osteosarcoma cells, ROS 17/2.8 [Bidwell et al. (1994b): Endocrinology 134:1738-1744]. Here, we determined that these same PTH-responsive proteins were expressed in rat metaphyseal osteoblasts. We identified the 200 kD protein as a non-muscle myosin. Although the molecular weights, subcellular distribution, and half-lives of the 190 and 160 kD proteins were similar to topoisomerase II-alpha and -beta, nuclear matrix enzymes that mediate DNA topology, the 190 and 160 kD proteins did not interact with topoisomerase antibodies. Nevertheless, the expression of topoisomerase II-alpha, and NuMA, a component of the nuclear core filaments, was also regulated by PTH in the osteosarcoma cells. The 190 kD protein was selectively expressed in bone cells as it was not observed in OK opossum kidney cells, H4 hepatoma cells, or NIH3T3 cells. PTH attenuated mRNA expression of the PTH receptor in our cell preparations. These results demonstrate that PTH selectively alters the expression of osteoblast membrane, cytoskeletal, and nucleoskeletal proteins. Topoisomerase II-alpha, NuMA, and the 190 and 160 kD proteins may direct the nuclear PTH signalling pathways to the target genes and play a structural role in osteoblast gene expression.

Animals↗

PubMed1996

Ocular hemodynamic effects of acute ethanol ingestion.

PURPOSE: Because the protean biological effects of ethanol include acute alterations in both cortical function and circulatory control, we investigated the effect of acute alcohol consumption on retrobulbar hemodynamics and contrast sensitivity in healthy human volunteers. SUBJECTS AND METHODS: Twelve young adults received orange juice with and without ethanol in a double-masked fashion. The ethanol dose was sufficient to raise blood alcohol to 0.07 +/- 0.003 g/dl. Retrobulbar hemodynamics were assessed at baseline and twice at elevated blood alcohol by color Doppler imaging. RESULTS: Acute elevation of blood alcohol lowered intraocular pressure from 13.0 +/- 0.7 to 10.7 +/- 0.7 mm Hg (p < 0.05). In contrast, elevated blood alcohol left peak systolic velocity, end-diastolic velocity and the resistance index constant in three retrobulbar arteries (ophthalmic, central retinal and posterior ciliary). For example, in the central retinal artery, peak systolic velocity, end-diastolic velocity and the resistance index averaged 11.0 +/- 1.3 cm/s, 2.8 +/- 0.4 cm/s and 0.75 +/- 0.03 before ethanol, as compared with 10.5 +/- 1.0 cm/s, 2.9 +/- 0.3 cm/s and 0.72 +/- 0.03 after ethanol (all p = NS). Alcohol ingestion also failed to alter either visual acuity or contrast sensitivity, as assessed under both photopic and mesopic conditions. CONCLUSIONS: Although ethanol has widespread cognitive and cardiovascular effects, at blood levels near legal definitions of intoxication we found it ineffective in altering either retrobulbar hemodynamics or contrast sensitivity.

Adult↗

PubMed1994

Diet-disease interactions at the molecular level: an experimental paradigm.

High levels of dietary fat enhance the severity of certain cancers, obesity, and cardiovascular diseases in susceptible individuals usually after prolonged exposure. We have been developing methods for identifying and characterizing genes regulated by the level of dietary fat for the purpose of determining their role in diseases promoted by high levels of dietary fat, particularly cancer and atherosclerosis. Our protocol employs semi-purified diets of reproducible composition fed to normal inbred mice to obtain reagents for studying of molecular events that lead to pathology. Our early studies demonstrated that different levels of dietary fat cause the accumulation or change in expression of two genes, designated Lfm-1 and Lfm-2 (low fat mammary) in mouse mammary glands and selected other tissues. The Lfm-2 gene is stearoyl CoA desaturase, a gene known to be regulated by dietary fat and insulin levels. The Lfm-1 gene is highly similar to the e subunits of bovine and rat F1F0-ATPases. A Lfm-1 restriction fragment length polymorphism located on chromosome 8 is associated with atherosclerosis in certain inbred strains of mice warranting additional tests to determine whether it is involved in initiation or promotion of heart disease. The experimental approach has the potential for analyzing genes regulated by approximately 50 essential nutrients or other dietary constituents. A potential outcome of this research is the development of reagents which can be used to predict the risk of diet-related diseases in individuals.

Alleles↗

PubMed1993

The politics of reform: public health insurance in Canada.

The centerpiece of Canadian health policy is a system of public health insurance covering the cost of hospital and medical services for all Canadians. The author analyzes the historical development of this policy and critically assesses its structure and dynamics. He argues that health insurance was won by Canadian workers through protracted industrial and political struggle. At the same time, health insurance was accommodated to the existing structure of power and privilege within the health care delivery system, which precluded a significant shift in the distribution of health care consumption and perpetuated the "irrationality" of a system that treats health as a problem located in the sphere of personal consumption.

Canada↗

PubMed1989

Limitations of flow cytometric DNA analysis for the diagnosis of bladder cancer.

Flow cytometric analysis was done on exfoliated urothelial cells from 11 control patients and 31 patients with transitional cell carcinoma: 9 grade I, 11 grade II, and 11 grade III. The determination of aneuploidy by DNA analysis did not provide identification of low-grade tumor cells. Other flow cytometric parameters of cellular change such as cell size, nuclear size, nuclear/cytoplasmic ratio, or cell refractivity may provide better identification of low-grade lesions.

Carcinoma, Transitional Cell↗

PubMed1987

Bladder cancer detection and surveillance: carcinoembryonic antigen as a monitor of neoplastic transformation.

Routine cytopathology of exfoliated urothelial cells will identify only 70% of patients with transitional cell carcinoma (TCC) because most well-differentiated bladder tumors are not detected. Carcinoembryonic antigen (CEA) was identified on urothelial cancer cells from 66% of patients with grade I TCC, 65% with grade II TCC, 65% with grade III TCC, and 80% of patients with CIS. Immunoperoxidase labelling of CEA can enhance the sensitivity of exfoliative cytology.

Carcinoembryonic Antigen↗

PubMed1987

Irritation and stripping effects of adhesive tapes on skin layers of coronary artery bypass graft patients.

Explore the source record for details and available documents.

Acrylates↗

PubMed1984

Intrapericardial diaphragmatic hernia after subxiphoid epicardial pacemaker insertion: case reports.

The first two cases of intrapericardial diaphragmatic hernia following a subxiphoid epicardial pacemaker insertion are reported. Factors deemed responsible for this rare complication in one case were previous gastrectomy with a resulting paucity of omentum, and entrance into the peritoneal cavity during the pacemaker procedure.

Aged↗

PubMed1977