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Biomedical subjects

J A Balint

Publications and source records attributed to J A Balint.

At least 19 recordsLinked to original sources
PubMed2003

Five years of complete remission of gastric diffuse large B cell lymphoma after eradication of Helicobacter pylori infection.

Long term follow up data are not available for cases of diffuse large B cell gastric lymphoma treated by eradicating Helicobacter pylori alone. We present the case of an 82 year old man with diffuse large B cell lymphoma localised to the stomach which responded to H pylori eradication and which has not recurred after more than five years of close follow up. Our patient was not a candidate for other modalities of treatment. This case demonstrates that the option of treating H pylori infection as the initial trial of treatment for localised diffuse large B cell lymphoma is appropriate for consideration. If medical therapy using eradication of H pylori is used, it is essential that the patient undergoes close observation and repeated surveillance endoscopies.

Aged↗
PubMed2000

Decisions at the end of life.

This paper presents a system for making decisions at the end of life. It emphasizes the role of patient autonomy and the importance of patient and family participation with the physician in decision-making. Definitions are presented for the terms: terminal illness, withholding and withdrawing life sustaining treatment, physician assisted suicide and euthanasia. Three cases are briefly described to illustrate the application of the decision-making system. A detailed discussion is then presented of the divergent views expressed by different authors about the moral differences or similarities between foregoing life sustaining treatment and physician assistance in dying. It is concluded that the view that these two actions are fundamentally different, as supported by the United States Supreme Court, in 1997, is the correct one. Physician assisted suicide (PAS) remains a controversial issue. Physicians and societies in individual countries must work out their own approaches to PAS. However, foregoing invasive or intensive life support in terminally ill patients consistent with their wishes is considered appropriate.

Aged↗
PubMed1994

Remedial medical education.

Continuing medical education plays an essential role in efforts to improve physician performance. This article deals with remedial or personalized physician education. The experience of selected institutions and state organizations that have and/or continue to provide such remedial education is reviewed. The emphasis of remedial or focused physician education is educational enhancement, not suspension or revocation of license.

Canada↗
PubMed1994

Performance-based assessment of moral reasoning and ethical judgment among medical students.

BACKGROUND: An assessment technique was developed to measure the abilities of medical students to deal with moral and ethical issues. METHOD: Assessments of ability in moral reasoning and ethical judgement were administered in July and August of 1991 and 1992 to 511 fourth-year students from five northeastern U.S. medical schools. Five behavioral parameters were measured during each student's encounter with a standardized patient (SP), who graded the student's performance. Immediately following the encounter, each student was asked to describe at least two moral conflicts in a short essay, which was graded by the authors of the study. Statistical analysis used chi-square, Fisher's exact test, and Spearman rank correlation. RESULTS: Poor performance on the interactive tasks with the SP was observed among 11% of the students; on the written (analytical) tasks, among 14.1%; and on both portions of the assessment, among 2.3%. Little relationship existed between performances on the interactive and written portions. CONCLUSION: That a low degree of relationship was found between the students' performances on the interactive and written portions of the assessment suggests that the two portions measure different skills. To address student differences, the authors formulated a model for categorizing students that would be useful in individualizing remedial strategies.

Attitude of Health Personnel↗
PubMed1993

Effects of aging on intestinal lipid absorption.

Because of the "graying" of the population there is increasing interest in age-related changes in organ physiology. Impairment of lipid absorption, if present, could lead to malnutrition in the elderly while increased uptake of cholesterol could contribute to the rise in serum cholesterol levels seen in older individuals. This review critically analyzes the available information on age-related changes in digestive and absorptive physiology of lipids. Overall, the data suggest that lipid digestion and absorption are, in general, well-preserved in aging. However, intercurrent illness or experimental stress may produce impairment in aging animals and humans that are not seen in younger controls. Areas deserving more detailed study are identified in this review and include intestinal motility, adaptation to stress, and assembly and transport of lipoproteins from enterocytes to lymph.

Aging↗
PubMed1993

Investigation of gastrointestinal bleeding in patients with end stage renal disease.

In order to evaluate the source and course of gastrointestinal bleeding in patients with established renal insufficiency, we reviewed data on 40 patients with renal failure and gastrointestinal bleeding seen over 2 yr. A randomly selected control group of 39 patients without renal failure was used for comparison. Medical records of our University Hospital were reviewed, and patients with a documented gastrointestinal bleed and renal insufficiency (creatinine greater than 1.7 mg/dl) were included in this study. Panendoscopy was the most valuable procedure in terms of establishing a diagnosis as to the cause of bleeding. Colonoscopy was of questionable value unless the bleed was clearly of lower intestinal origin. Recurrent bleeding during the index admission occurred with the same frequency in both groups of patients. Both groups used nonsteroidal anti-inflammatory agents frequently. The findings and outcome for this group of patients with renal failure was comparable to the control patients with gastrointestinal bleeding.

Adult↗
PubMed1986

Formation and transport of chylomicrons by enterocytes to the lymphatics.

Digestion of triglyceride in the intestine results in the production of 2-monoglyceride and fatty acid. Phosphatidylcholine is hydrolyzed in the lumen to form lysophosphatidylcholine before its absorption. These digestion products are absorbed by the enterocytes through simple diffusion. In contrast, cholesterol absorption seems specific and is energy dependent. After entry into the enterocytes, these lipid digestion products migrate to the endoplasmic reticulum. Both fatty acid-binding protein and sterol carrier protein may be involved in the intracellular transport of fatty acid and cholesterol, respectively. Through predominantly the monoglyceride pathway, monoglycerides and fatty acids are resynthesized to form triglyceride in the endoplasmic reticulum. The lipid droplets, coated with cholesterol, phospholipid, and apolipoproteins, are then further processed in the Golgi apparatus before being released by the enterocytes through exocytosis. As yet, little is known of the factors regulating the formation and release of these chylomicrons by the enterocytes. Although apolipoprotein B is a prerequisite for the formation of chylomicrons, the question of whether its supply is rate limiting for chylomicron formation remains to be demonstrated. Other factors that may play a role in chylomicron formation are luminal phospholipid supply, Ca2+, and microtubules. Chylomicrons and very low-density lipoproteins are probably produced by the enterocytes via different pathways. For example, Pluronic L-81, a hydrophobic surfactant, affects only chylomicron formation and has little effect on very low-density lipoprotein production. The movement of chylomicrons from the intercellular space through the basement membrane to the lamina propria is not fully understood. Once inside the lamina propria, the movement of chylomicrons is probably by diffusion and is greatly facilitated by interstitial hydration; thus the lymphogogic effect of fat absorption may serve an important function for the transfer of chylomicrons from the enterocytes to the lacteal.

Animals↗
PubMed1985

The effects of essential fatty acid deficiency on pulmonary alveolar macrophage function.

Male rats were maintained for periods of up to 16 weeks on a fat free diet which was supplemented with either 4% tripalmitin (essential fatty acid [EFA] deficient) or with 4% safflower oil (SAFF, control). Pulmonary alveolar macrophages (PAM) were obtained by lung lavage. PAM from EFA deficient rats had reduced phagocytic activity and capacity. Intracellular killing of ingested yeast was also reduced by EFA deficiency. The activity of acid phosphatase, beta-glucuronidase and cathepsin D from PAM was not altered by dietary treatment. Transmission electron microscopy failed to show any consistent morphologic differences between PAM from EFA deficient and SAFF animals, but did confirm the decreased phagocytosis by PAM from EFA deficient rats. However, scanning electron microscopy did show loss of pseudopodia in PAM from EFA deficient rats. EFA deficiency was demonstrated by analyzing the methyl esters of the fatty aids from the total lipid extract of PAM. The arachidonate content was decreased while the eicosatrienoate content was increased in PAM derived from rats fed the EFA deficient diet. In an effort to elucidate further the mechanism of action of EFA deficiency in impairing phagocytosis by PAM, inhibitors of various reactions which lead to oxygenated derivatives of arachidonate were studied using PAM from chow fed rats. Some of these inhibitors were effective in diminishing phagocytosis. Furthermore, PAM from these preparations when fixed in suspension and examined with scanning electron microscopy showed morphological changes similar to those seen in EFA deficiency. This similarity of surface ultrastructural changes suggests that EFA deficiency may impair phagocytic function of PAM by reducing availability of an oxygenated derivative of arachidonic acid.

Acid Phosphatase↗
PubMed1982

Maximal lymphatic triglyceride transport rate from the rat small intestine.

In previous studies, we demonstrated that the hydrophobic surfactant Pluronic L-81 blocks lymphatic triglyceride transport from the small intestine and leads to accumulation of triglyceride in the mucosa. The onset of action of Pluronic L-81 is rapid and quickly reversed once its administration is discontinued. We have taken advantage of these effects of Pluronic L-81 on intestinal lipid transport in order to determine the apparent maximal triglyceride transport capacity of the proximal half of the rat small bowel using lymph fistula rats infused intraduodenally with a phosphate-buffered, taurocholate-stabilized emulsion containing 40 mumol [3H]triolein and 0.5 mg Pluronic L-81 at 3 ml/h for 8 h to load the proximal small bowel with lipid. Studies were done in one group of rats in order to be certain that only the proximal half of the small bowel contained 3H-lipid after this period of infusion. In other rats treated similarly, the 8 h of lipid-Pluronic L-81 infusion were followed by infusion of 3 ml/h of 0.15 M salt solution for 5 h. Lymphatic transport of lipid was determined throughout the entire period of infusion. During lipid-Pluronic L-81 infusion, transport of 3H-triglyceride fatty acid into lymph was only 22-27 mumol/h but rose steadily after substitution of saline and reached a maximal transport rate of 109 +/- 6.2 mumol/h (means +/- SE) after 3.5 h. During this 3.5-h period, the amount of 3H-lipid in the proximal mucosa declined from 530 to 263 mumol. While Pluronic L-81 was infused, only very low-density-lipoprotein-sized particles were seen in lymph by electron microscopy, whereas, at the peak of triglyceride transport during saline infusion, chylomicrons of up to 6,000 A were observed in lymph.

Animals↗
PubMed1981

Desaturation of endogenous and exogenous palmitate in lung tissue in vitro.

lung slices from rats fed a fat-free diet supplemented with safflower oil (control) or tripalmitoylglycerol (essential fatty acid [EFA]-deficient) were incubated with [14C]acetate, [14C]palmitate, or [14C]stearate. Of the 14C recovered in phospholipids after incubation with [14C]acetate, more than 87% was in 16-carbon fatty acids. Desaturation, as assayed by the percentage of radioactivity in monoenoates in phospholipid fatty acids, was generally double in EFA-deficient slices compared to control slices, regardless of substrate. Desaturation was significantly greater in slices incubated with with acetate or octanoate compared to palmitate, indicating that endogenously synthesized palmitate was desaturated more actively than that derived from an exogenous source.

Animals↗
PubMed1981

Intra-arterial tissue adhesive for medical splenectomy in humans.

Bucrylate (isobutyl 2-cyanoacrylate) was used for the transcatheter embolization of the splenic artery in 4 patients with bleeding gastric varices secondary to splenic vein thrombosis, 3 patients with symptoms of hypersplenism, and 8 patients with bleeding esophageal varices secondary to portal hypertension. The splenic artery was completely occluded in 13 patients and partially occluded in 2. In all but one of the patients, functioning splenic tissue was preserved and no abscess developed. Medical splenectomy with Bucrylate appears to be a safe and effective method for treating bleeding gastric varices secondary to splenic vein thrombosis, and it can alleviate symptoms of hypersplenism. Its role in controlling bleeding from esophageal varices in patients with generalized portal hypertension is worth further study.

Adhesives↗
PubMed1981

Acute inhibition of intestinal lipid transport by Pluronic L-81 in the rat.

Lymph fistula rats were used to determine the acute effects of the hydrophobic surfactant, Pluronic L-81, on lipid transport by the small bowel. Animals were infused intraduodenally with a lipid emulsion containing [3H]triolein and Pluronic L-81, and the rate of intestinal transport of absorbed lipid into lymph was studied using liquid scintillation spectrometry. With this technique, various dose levels of Pluronic L-81 were analyzed for a possible inhibitory effect on lipid transport. Also, the rate at which this agent produced inhibition of intestinal lipid transport was determined. Results were correlated with electron microscopic studies of jejunal enterocytes and lipoprotein particles recovered in intestinal lymph. Infusion of Pluronic L-81 at a rate of 0.25 mg/h had no effect, but infusion at 0.5 and 1 mg/h produced a dramatic reduction in lipid transport by the small bowel. The rate of inhibition of lymphatic lipid output was rapid, with a t1/2 of 69 min for the 0.5 mg/h dose and 35 min for the 1 mg/h dose. This inhibition of lipid transport was associated with marked mucosal accumulation of lipid as demonstrated by radiochemical and morphological data. By electron microscopic analysis, only very low-density lipoprotein-sized particles were transported into lymph by enterocytes exposed to an effective dose of Pluronic L-81. It is concluded that small amounts of Pluronic L-81 produce a striking inhibition in the intracellular transport of chylomicron-sized particles, thereby blocking secretion of chylomicrons by the enterocytes. Furthermore, this action is very rapidly produced by effective doses of this agent.

Animals↗
PubMed1981

Role of biliary phosphatidylcholine in the absorption and transport of dietary triolein in the rat.

This study was undertaken to determine the role of luminal phosphatidylcholine in the intestinal absorption and transport of glycerol trioleate in the rat. Rats with bile and thoracic duct lymph fistulas were infused with a bile salt-stabilized emulsion of glycerol trioleate only or with either dioleoyl or dipalmitoyl phosphatidylcholine added. Uptake of infused lipid was greater than 95% in all groups. The presence of supplemental phosphatidylcholine in the infusate greatly enhanced the lymphatic triglyceride and phosphatidylcholine outputs in the bile-diverted rats as compared with rats without phosphatidylcholine supplementation. There was no difference in lipid outputs between the dioleoyl or dipalmitoyl phosphatidylcholine-supplemented rats. The fatty acid pattern of the lymph phosphatidylcholine of the two groups of phosphatidylcholine-supplemented rats reflected that of the added phosphatidylcholine. In the absence of luminal phosphatidylcholine there was increased accumulation of mucosal triglyceride and evidence suggesting increased portal transport of absorbed fatty acid. Therefore, this study demonstrated that the presence of luminal phosphatidylcholine is important for the normal lymphatic transport of the absorbed digestion products of triglyceride, the major dietary fat.

Animals↗
PubMed1980

Ileal uptake of oleic acid: evidence for adaptive response to high fat feeding.

When I-14C oleic acid at 120 micron Eq/hr was infused into the duodenum in normal rats in a micellar solution with mono-olein (60 mu moles/hr) in 15 mM taurocholate over 6 hr uptake was nearly complete (97%). However, when this same solution was infused into the mid small bowel in control animals uptake was incomplete (88.9 +/- 2.6%, mean +/- SEM, P < 0.01). After 4 weeks on a high fat diet, containing 45% vegetable oil by weight, oleic acid uptake increased to 98.1 +/- 0.1% (P < 0.01 compared to controls). The improved uptake of oleic acid was associated with increased dry weight of mucosa in the proximal half of the ileum from 109 +/- 8.8/20 cm in controls to 135.6 +/- 7.3 mg/20 cm in high fat diet fed rats (P < 0.05), while protein increased from 107.4 +/- 6.5 to 124.9 +/- 4.8 mg/20 cm (P < 0.05). There was no increase in DNA expressed as mg/g wet weight of mucosa or in number of cells per villus. Lipid content of the mucosa and degree of esterification of absorbed oleic also were unaltered. These results indicate that the mucosa of the proximal ileum responds to high fat feeding by hypertrophy (increased mass and protein, with no change in DNA content or cell number) and that this change is associated with more complete uptake of oleic acid reaching this part of the small bowel.

Adaptation, Physiological↗
PubMed1980

Effect of hydrophobic surfactant (Pluronic L-81) on lymphatic lipid transport in the rat.

The effect of chronic feeding (3-4 wk) of the hydrophobic surfactant, Pluronic L-81, on the lymphatic transport of triglyceride and cholesterol was studied in rats with thoracic duct fistula. A lipid emulsion containing [3H]triolein (13.3 mM), [14C]cholesterol (2.6 mM), phosphatidylcholine (2.9 mM), sodium taurocholate (19 mM), with 0.17 mg/ml (experimental) or without Pluronic L-81 (L-81) added (control) was infused at the rate of 3 ml/h. Lymph triglyceride and cholesterol outputs were greatly impaired in the experimental rats compared to the control rats. The phospholipid output compared to the control was also reduced but to a lesser extent in the experimental rats. Comparable recovery of radioactive 3H-labeled lipid and [14C]cholesterol from the intestinal lumen of control and experimental rats showed that digestion and absorption were not impaired in the experimental rats. The distribution of mucosal 3H radioactivity in various lipid fractions showed no impairment in reesterification. The greatly depressed lymphatic lipid transport was associated with marked accumulation of absorbed lipid in enterocytes, suggesting that Pluronic L-81 interferes with lipoprotein assembly and/or exit of lipoproteins from the mucosal cells. The animals fed chronically for 4-6 wk regained their ability to transport lipid 24 h after termination of L-81 feeding. The effect of this agent, therefore, is readily reversible.

Animals↗