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Biomedical subjects

J D Jackson

Publications and source records attributed to J D Jackson.

At least 73 records · Page 4Linked to original sources
PubMed1990

In vivo administration of antibody to interleukin-5 inhibits increased generation of eosinophils and their progenitors in bone marrow of parasitized mice.

Bone marrow of mice parasitized with Nippostrongylus brasiliensis showed increased numbers of eosinophils as early as 4 days after infection. By day 7, their bone marrow also contained elevated numbers of progenitors that form small eosinophil colonies (20 to 50 cells) in soft agar cultures supplemented with interleukin-5 (IL-5). However, when mice were infused with anti-IL-5 antibodies at the time of infection, the number of recognizable eosinophils present in bone marrow remained low and eventually dropped below normal levels. The antibody treatment also prevented increased generation of IL-5-responsive precursors capable of differentiating into mature eosinophils in liquid culture and inhibited the generation of progenitor cells capable of forming small eosinophil colonies or clusters in soft agar cultures. The results of these in vivo experiments directly show that IL-5 is an essential regulatory molecule required for the bone marrow-dependent phase of a parasite-induced eosinophilia.

Animals↗
PubMed1989

The influence of advertising on tobacco consumption: some problems with Chetwynd et al.'s analysis.

In a recent study of the relationship between cigarette advertising and the aggregate consumption of cigarettes in New Zealand between 1973 and 1985, Chetwynd et al. (1988) argue that quarterly data suggest that advertising affects overall consumption of cigarettes with an elasticity of +0.07. In addition, they argue that advertising has a 'carry over' effect of about four quarters on current consumption. These results are potentially important for two reasons. Although the evidence is mixed, the conventional view is that cigarette advertising affects brand choice among smokers but not aggregate demand for cigarettes. Chetwynd et al.'s results, (hereafter, Chetwynd) contradict this traditional view. Secondly, if advertising does increase the aggregate demand for cigarettes, then a public policy banning cigarette advertising might reduce aggregate demand for cigarettes. Unfortunately, the Chetwynd, study is sufficiently flawed with conceptual and econometric problems that their inference that advertising increases cigarette demand is questionable. Certainly cigarette advertising may increase or decrease cigarette consumption. The point we wish to make is that, any inference one way or the other based on the results of Chetwynd, cannot be viewed as well-grounded in either scientific methodology or statistical principles.

Advertising↗
PubMed1989

Comparison of the growth and metastasis of four human intestinal tumor cell line xenografts.

The growth and metastasis of four human intestinal tumor cell lines: one duodenal adenocarcinoma (HTB-40) and three adenocarcinomas of the colon (CCL-218, CCL-222 and HT-29) have been compared in vitro and in vivo in nude mice. HTB-40 was the fastest growing cell line in vitro with a doubling time (DT) of 14.8 h. CCL-218 and CCL-222 grew more slowly in vitro with doubling times of 21.6 and 22.8 hours, respectively. All three of these tumors grew more slowly in vivo with doubling times ranging from 39.1 h (CCL-218 in male nude mice) to 65.3 h (CCL-222). The growth of CCL-218 cells was significantly slower in female nude mice DT 51.0 h). HT-29 was the slowest growing in vitro (DT 23.8 h) and in vivo (DT about 100 h). HT-29 also showed the greatest discrepancy between its DT measured in vivo as compared to in vitro, suggesting a greater clonogenic cell loss from HT-29 tumors in vivo. Histologic evaluation of these tumors grown subcutaneously in nude mice showed all to be anaplastic and to produce liver micrometastases. However, more extensive abdominal and liver metastases were observed in the nude mice injected with HT-29 cells, and some of these metastases had morphologic features of moderately well-differentiated epithelium. These results indicate the usefulness of the HT-29 tumor cell line as an experimental model of metastasis from a human colonic adenocarcinoma.

Animals↗
PubMed1988

PaperChase: computerized bibliographical retrieval for the physician.

PaperChase is a computer program that permits any physician or scientist to search the National Library of Medicine's MEDLINE data base of references to the biomedical literature. Written for the clinician rather than for the search librarian, PaperChase permits the user to search the entire MEDLINE collection of over 5,000,000 references published in 4,000 biomedical journals dating back to 1966. PaperChase is now available throughout the world to anyone who has a computer terminal or personal computer, and a modem. No special training is needed for a successful search. There is no user's manual. Users can search by title word, Medical Subject Heading, author's name, journal title, year of publication, language of publication, or any combination of the above. Users can read abstracts online, and they can request that a photocopy of the full text of any article be mailed to them.

Abstracting and Indexing↗
PubMed1987

Cell surface properties associated with malignancy of metastatic large cell lymphoma cells.

The highly malignant and metastatic RAW117-H10 cell line was developed by in vivo selection from the Abelson leukemia virus induced parental RAW117-P lymphoma. In this study we have characterized these cell lines with regard to their expression of lymphocyte and macrophage differentiation antigens, adherence, phagocytic properties, binding of various lectins, binding of antibodies to glycolipid asialo-monoganglioside, and the role of butanol extractable cell surface molecules to determine if any of these cell surface properties are associated with the malignant potential of RAW117-H10 cells. The only major difference in immunological phenotypes between RAW117-P and RAW117-H10 cells was an increased expression of Thy-1 molecules by the latter. However, the highly malignant RAW117-H10 cells bound significantly less concanavalin A, Ricinia communis agglutinin, succinylated wheat germ agglutinin, and particularly anti-asialomonoganglioside than their parental counterpart and were resistant to natural killer cell mediated cytolysis. Removal of butanol extractable cell surface molecules significantly decreased the malignancy of RAW117-H10 cells and increased their susceptibility to natural killer cell mediated cytolysis. The butanol treated RAW117-H10 cells regained high in vivo malignancy when recultured for 3 days to permit regeneration of their cell surface components. The butanol extracted RAW117-H10 cells still expressed high levels of Thy-1 indicating that this most probably represented "inappropriate" antigen expression. Since the expression of lymphocyte differentiation antigens did not correlate with the malignant behavior of the cells, we postulate that these antigenic differences merely represent phenotypic variation. The decreased malignant potential of the butanol treated RAW117-H10 cells did correlate with increased cell surface anti-asialomonoganglioside binding (glycolipid) and increased natural killer cell susceptibility.

Animals↗
PubMed1986

Effects of endotoxin on coronary vascular resistance in the isolated blood-perfused rabbit heart.

Rabbit hearts were excised and perfused with blood pumped through a cannula placed in the aortic root. A fluid-filled balloon-tipped catheter was positioned in the left ventricle for the measurement of left ventricular pressure and dP/dt. Total coronary vascular resistance (CVR) was calculated by dividing the coronary perfusion pressure by the rate of coronary blood flow. Following stabilization, coronary blood flow was held at a constant rate. Compared to control hearts, endotoxin (E. coli) added directly to the blood perfusate (6 mg/80 ml of circulating blood) had no effect on CVR or left ventricular dP/dt. In contrast, changing the perfusate to blood obtained from rabbits previously given endotoxin (LD100; 6 mg/kg IV) resulted in significantly higher CVR, without depression of left ventricular dP/dt. This increase in CVR was observed not only when the endotoxemic donor rabbits were hypotensive at the time the blood was obtained (4-6 hours following endotoxin administration), but also when the endotoxemic donors remained normotensive (blood withdrawn 30 minutes following endotoxin administration). A pathologic increase in CVR might contribute to the myocardial ischemia and contractile dysfunction observed in endotoxin shock.

Animals↗
PubMed1985

Clinical computing in a teaching hospital.

This report describes a hospital-wide clinical computing system that permits physicians, nurses, medical students, and other health workers to retrieve data from the clinical laboratories; to look up reports from the departments of radiology and pathology; to look up demographic data and outpatient visits; to look up prescriptions filled in the outpatient pharmacy; to perform bibliographic retrieval of the MEDLINE data base; to read, write, retract, edit, and forward electronic mail; and to request delivery of a patient's chart. During a one-week study period, from 300 video display terminals located throughout the hospital, 818 patient care providers used a common registry of 539,000 patients to look up clinical and laboratory data 16,768 times; 477 other hospital workers used the patient registry 46,579 times. In a separate study of 586 health care providers, 470 (80 per cent) indicated that they used computer terminals "most of the time" to look up laboratory results; in contrast, 48 (8 per cent) preferred printed reports. Of 545 hospital workers, 440 (81 per cent) indicated that the computer terminals definitely or probably made their work more accurate, and 452 (83 per cent) indicated that terminals enabled them to work faster. The large amount of use by clinicians and their judgment that the computer has been so helpful to them suggests that a reliable, comprehensive, and easy-to-use computer system can contribute substantially to the quality of patient care.

Boston↗
PubMed1985

Differentiation inducing effects of butyrate and DMSO on human intestinal tumor cell lines in culture.

In the present report, we have studied the effects of butyrate and dimethyl sulfoxide (DMSO) on the characteristics of four human intestinal tumor cell lines in vitro; namely a duodenal adenocarcinoma HTB-40 and three adenocarcinomas of colon: HT-29, CCL-218, and CCL-222. In the presence of concentrations of 2 mM butyrate and 2% DMSO the growth of all these four cell lines was significantly inhibited. Both these agents lengthened the doubling time of these cell lines by about twofold. In addition, the morphology of the treated cells was altered. All four cell lines grow in semisolid agar and form characteristic colonies. Butyrate and DMSO inhibited the colony forming efficiency of these cell lines by 40-60%. Using flow cytometric analysis, the cells that were grown in the presence of butyrate and DMSO were analyzed for their lectin-binding properties. For this purpose the lectins used were concanavalin-A (Con-A), peanut agglutinin (PNA), wheat germ agglutinin (WGA), and succinylated wheat germ agglutinin (SWGA). All four cell lines showed an increase in lectin-binding cells. CCL-218, which showed no PNA binding when grown without these agents, acquired about 25% reactivity when grown in the presence of butyrate or DMSO. All these cell lines showed an increase in the percentage of positive cells for the lectin SWGA that unlike WGA does not bind to sialic acid on the cell surface, suggesting an increase in nonsialated residues on all the treated cells. These results indicate a differentiation inducing effect of butyrate and DMSO on these cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)

Butyrates↗
PubMed1984

Analysis of electronically pulsed versus quasi-continuous wave carbon dioxide lasers in an animal model.

In this study we sought to compare laser tissue interaction in both the quasi-continuous waveform and electronically pulsed waveform of the carbon dioxide laser. An intramode analysis of the electronically pulsed form (at 350 and 650 pulses per second) was also undertaken. Intraperitoneal laser incisions were made on New Zealand white female virginal rabbits and tested at days 0, 5, 15, and 20. Testing involved proximal and midsection analysis of the laser sites to evaluate total area of vaporization, total area of tissue thermal damage, maximum diameter of injury at epithelial surface, maximum depth of laser penetration, angle of vaporization crater edges, and angle of tissue thermal injury of the three modes. Analysis of proximal versus midsection preparation revealed different zones of vaporization and injury within the same laser site. The zone of injury with respect to time was nonuniform, suggesting that the laser output in the electronically pulsed mode was not constant. An in vivo tissue lens phenomenon was also detected, resulting in a compound thermal vaporization and injury pattern.

Animals↗
PubMed1984

Drug metabolism in spontaneously diabetic guinea pigs.

Both sexes of spontaneously diabetic guinea pigs exhibit hyperinsulinemia (greater than 4-fold normal). This diabetic state is associated with the inhibition of hepatic drug metabolism in males but not females.

Aminopyrine↗