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Biomedical subjects

D Hollander

Publications and source records attributed to D Hollander.

At least 181 records · Page 10Linked to original sources
PubMed1983

Intestinal exsorption of oleic acid: influence of aging, bile, pH and ethanol.

The transfer of oleic acid from the circulation into the intestinal lumen perfusate (exsorption) was investigated in vivo in male Sprague-Dawley rats. Following intravenous infusion of oleic acid, its appearance in the intestinal perfusate was assessed over a 3-hour period. The relationship between exsorption rate and the amount of infused oleic acid delineated a linear plot. Oleic acid exsorption rate increased as the taurocholate concentration was raised to 10 mM in the intestinal perfusate. In contrast, oleic acid exsorption rate decreased following decrease in the intestinal perfusate pH, or increase in the intestinal perfusate's concentrations of oleic, butyric and octanoic acids or following the additions of increasing concentrations of ethanol to the intestinal perfusate. Increase in the age of the animals from 3 to 21 months resulted in a decrease of oleic acid exsorption. These data indicate that exsorption of oleic acid into the intestinal perfusate is not simply a process of "leakiness" of the intestinal epithelium. Rather, exsorption of this fatty acid is modified by factors that change the characteristics of the perfusate or modify the characteristics of the intestinal epithelium or the unstirred water layer at the luminal surface of the small intestine.

Aging↗
PubMed1983

Aging: its influence on the intestinal unstirred water layer thickness, surface area, and resistance in the unanesthetized rat.

The intestinal absorption of some nutrients changes with aging. As the unstirred water layer (UWL) is an important rate limiting step in the absorption of nutrients in general and of lipid soluble nutrients in particular, we investigated possible changes in the UWL dimensions in the aging rat in vivo. We measured the thickness (d) of the UWL using rapid changes in the luminal sodium concentration to induce changes in the transmucosal potential differences. We assessed the surface area (Sw) and resistance (d/SwD) of the UWL at varying flow rates by using increasingly lipophilic medium chain saturated alcohols as probes. At high UWL resistance, d decreased from 318 to 268 microns between 1 and 29 months of age. As the animals aged, Sw changed from 114 to 106 cm2/100 cm and from 262 to 214 cm2/100 cm at low and high flow rates, respectively, using dodecanol as a probe. The resistance of the UWL (d/SwD) remained relatively stable at all ages studied. These experiments demonstrate that age-related changes in absorption are dependent on the aqueous diffusion coefficient and degree of lipid solubility of the specific nutrients. At low UWL resistance, absorption of compounds with higher diffusion coefficients and greater aqueous solubility is decreased with aging. In contrast, previous studies have demonstrated that the absorption of nutrients with low diffusion coefficients and high lipid solubility increases with aging especially when the resistance of the UWL is high.

1-Octanol↗
PubMed1983

Arachidonic acid protection of gastric mucosa against alcohol injury: sequential analysis of morphologic and functional changes.

We have shown previously that arachidonic acid (AA) prevents gastric mucosal injury by ethanol (ETOH). The present study was designed to determine the sequence of morphological and functional changes in the gastric mucosa during ETOH-induced injury and AA-promoted protection. Fasted male rats received intragastrically 1 ml of vehicle (PL) or 1 ml of 120 mM AA followed 1 hr later by 2 ml of absolute ETOH. Mucosal changes were assessed at 10, 15, and 30 min and 1, 2, 3, 6, and 15 hr after ETOH: (1) macroscopically, histologically, and by scanning EM; and (2) by determinations of (a) mitotic activity and 3H-thymidine incorporation in vivo, (b) gastric volume, pH, and electrolytes, and (c) gastric PD. Macroscopic necrotic changes were present in PL-but not AA-pretreated animals throughout the 15 hr after ETOH. Histological examination and scanning EM showed desquamation of the surface epithelium at 10 min to 2 hr and deep necrotic lesions throughout the 15 hr after ETOH in PL-pretreated animals. In AA-pretreated rats, deep necrotic lesions did not occur, but desquamation of the surface epithelium was seen during the initial 30 min after ETOH. A continuous layer of the surface epithelium was restored within 3 hr after ETOH in AA group, with resumption of the transport and barrier functions. The main feature of AA protection of gastric mucosa against ETOH injury is preservation of the mucosal proliferative zone.

Animals↗
PubMed1982

Arachidonic acid protection of rat gastric mucosa against ethanol injury.

AA, an essential dietary fatty acid, is a precursor for synthesis of prostaglandins. The ability of prostaglandins to protect the gastric mucosa against ethanol injury prompted us to investigate the possibility of AA providing similar protection in the rat. AA or its solubilizer were instilled intragastrically 60 min prior to absolute ethanol. The gastric lining was examined at 3 and 15 hr after the administration of ethanol. The extent of damage was assessed both macroscopically and histologically. AA administration 30 or 60 min prior to ethanol ingestion protected the gastric mucosa against macroscopic and histological damage for 3 to 15 hr. The intragastric concentration of prostaglandin E2 was 5,000 to 13,000 times higher in the animals pretreated with AA than in the controls. The protective action of AA was markedly diminished by indomethacin pretreatment. Intrajejunal administration of AA did not protect the gastric mucosa. These experiments demonstrate that a dietary constitutent--arachidonic acid--can protect the gastric mucosa against alcohol injury by inducing the synthesis of prostaglandins by the gastric mucosa.

Animals↗
PubMed1981

The effect of massive weight loss on arterial oxygenation and pulmonary function tests.

Pulmonary function tests (PFTs) and arterial oxygenation were studied 24 hours preoperatively and again at varying times (5 to 20 months) during the postoperative weight loss of 37 morbidly obese patients. Among PFTs, expiratory reserve volume (ERV) demonstrated the most significant (P less than 0.001) improvement with weight loss. No clinically relevant differences were found after weight loss in FEV1, FVC, or MMEF. In 11 patients whose arterial blood gases were sampled before and after weight loss, a significant correlation was demonstrated between change in ERV and change in Pao2 (r = 0.59, P less than 0.05) and P(A-a)o2 (r = 0.76, P less than 0.01). When weight loss is expressed as either change in body mass index (delta BMI) or as a change in percent of ideal weight (delta wt), there existed a weight loss threshold for improvement in arterial oxygenation. A delta BMI of greater than 20 or a delta wt more than 100 per cent resulted in a significant improvement in Pao2 (P less than 0.01) or P(A-a)o2 (P less than 0.05). These data suggest that morbidly obese patients do not meaningfully improve FEV1, FVC, or MMEF with massive weight loss. However, there is a significant improvement in ERV that directly correlates with improvement in both Pao2, and P(A-a)o2.

Adult↗
PubMed1981

Socialisation scheme with a high staff-patient ratio.

Six months after a comprehensive socialisation scheme began, a prospective controlled study was carried out. The patients were tested in three practical sections - Cooking; Maintenance of Home and Clothing; Other Skills (eg. form-filling); and with a Questionnaire. Forty-eight members of an experimental group received socialisation training after initial testing. They and the 20 controls who did not undergo training were re-evaluated three months later. There was no significant difference between the groups in their initial scores. On retesting, the experimental group showed a significant improvement in Cooking (p less than 0.001), Home Maintenance (p less than 0.001) and the Questionnaire (p less than 0.05). Analysis of the inter-group differences showed significant superiority of the experimental group in Cooking (p less than 0.05) and Home Maintenance (p less than 0.05). It is suggested that such a socialisation scheme be considered for inclusion alongside other rehabilitation services in psychiatric hospitals. The emphasis on a high staff-to-patient ratio and the breakdown of each task into smaller steps emerged as essential elements in the training programme.

Activities of Daily Living↗
PubMed1981

Neutralizing capacity and cost effectiveness of antacids.

The prescribing physician is faced with a wide choice of antacid preparations. To provide a guide, we tested the commonly available antacids, both liquid and tablet, for their acid-neutralizing capacity. We calculated the cost effectiveness of antacids and tabulated the cost of 1 month of therapy. The acid-neutralizing capacity and cost effectiveness of liquid antacids are generally better than tablet antacids. The most effective liquid antacids, which are composed of either aluminum and magnesium hydroxide mixtures or calcium carbonate, vary in buffering capacity from 3 to 4.2 meq/mL of antacid and range in monthly cost of therapy from $35 to $74. In contrast, the five least effective liquid antacids vary in acid-neutralizing capacity from 0.3 to 2.3 meq/mL of antacid and in monthly cost of therapy from $78 to $498. Because the monthly cost of therapy is influenced primarily by the acid-neutralizing capacity of the antacid, a high-potency antacid should be prescribed. The taste and sodium content of the antacids should also be taken into account by the prescribing physician.

Aluminum Hydroxide↗
PubMed1981

Efficacy of sucralfate for duodenal ulcers: a multicenter, double-blind trial.

Sucralfate, a new drug for the treatment of duodenal ulcer, was tested in a multicenter, double-blind, placebo-controlled study. Fifty-five patients with endoscopically documented duodenal ulcers completed the trial successfully. Patients were treated four times daily with 1 g of sucralfate or placebo identical in appearance and taste. They were seen weekly for reinforcement of instructions, assessment of compliance, and clinical evaluation. The patients were reevaluated endoscopically at the end of the second and fourth weeks of therapy. After 4 weeks, 22 of 24 (91.7%) sucralfate-treated patients and 18 of 31 (58.1%) placebo-treated patients showed complete healing of duodenal ulcers (chi 2 = 7.70; p less than 0.01). Relief from ulcer discomfort paralleled the results of healing. We conclude that sucralfate is an effective agent for the treatment of duodenal ulcer.

Aluminum↗
PubMed1981

Intestinal absorption of aspirin. Influence of pH, taurocholate, ascorbate, and ethanol.

The small intestinal absorption of aspirin at pharmacological concentrations was studied in the unanesthetized rat by using a single-pass perfusion technique. The rate of aspirin absorption remained linear with its concentration (0.5 to 10 mM). Intestinal aspirin absorption increased as the concentration of hydrogen ion, sodium taurocholate, and ascorbic acid in the perfusate increased. Aspirin absorption did not change after ethanol addition. At pH 3.5 or 6.5, intestinal absorption of aspirin was greater than gastric absorption of the compound. Aspirin was not absorbed by the stomach at pH 6.5. These experiments indicate that aspirin can be absorbed to an appreciable extent in its ionized form by the small intestine but not by the stomach.

Animals↗
PubMed1980

Retinol lymphatic and portal transport: influence of pH, bile, and fatty acids.

Absorption of [3H]retinol into lymph and bile was studied in unanesthetized rats with cannulated thoracic and common bile ducts. Retinol in a micellar solution was infused into the duodenum. Absorption of retinol into lymph increased when the infusate's taurocholate concentration was increased to 10 mM, when the hydrogen ion concentration was increased, or when octanoic acid was added to the infusate. Absorption of retinol into lymph decreased when the taurocholate concentration was decreased to 5 mM or when long-chain unsaturated fatty acids or retinoic acid were added to the duodenal infusate. Retinol absorption into bile increased following additions of linoleic and arachidonic acids to the infusate, but absorption did not change following modifications of the infusate's taurocholate concentration or pH. These experiments, which demonstrate that intraluminal factors do modify the extrusion of retinol into bile and lymph, enhance our overall understanding of the process of absorption of this lipid nutrient.

Absorption↗
PubMed1979

Relatives and friends group in a psychiatric ward.

To enable relatives and friends of psychiatric patients in a 30-bed acute admission ward to meet the staff team together a relatives and friends group was initiated. The group was intended to provide a forum for questions about the patients' illness and treatment; allow feelings, such as anger and anxiety, about the patient's illness to be expressed; and enable relatives and friends to share their experiences and offer advice and support to each other. A study was designed to assess the feasibility of the group scheme. Relatives and friends were invited to the day room of the admission ward each Wednesday evening for one hour. The visitors chose their own topics for discussion and the staff team tried to answer questions and to facilitate a free exchange of views. An account of each meeting was documented, including details of attenders, the nature of the topics raised, and a simple measurement of some of the emotions expressed by the visitors. Overall, the effect of the meetings seemed positive and productive, for they allowed relatives and friends to ask questions about many topics, to express pent-up emotions, and to gain a better understanding and tolerance of the patient's illness. The relatives and friends group has become an integral part of treatment on the wards. Now that the feasibility of such a group is established, further studies are required to evaluate its efficacy.

Communication↗
PubMed1979

Linoleic acid absorption in the unanesthetized rat: mechanism of transport and influence of luminal factors on absorption.

Linoleic acid intestinal absorption was studied in the unanesthetized rat. At low (21-1260 micrometer) intraluminal concentrations, absorption took place by facilitated diffusion; while at high (1.26-2.5 mM) concentrations, simple diffusion was the predominant mechanism of transport. At low concentrations (840 micrometer), the equimolar additions of oleic, linolenic, and arachidonic acids or lecithin inhibited the absorption of linoleic acid. Substitution of potassium for sodium in the buffer solution, substitution of Tween 80 for sodium taurocholate, or decrease in the hydrogen ion concentration all resulted in decreased rate of linoleic acid absorption. Increase in sodium taurocholate concentration, or perfusate flow rate increased linoleic acid's absorption. These experiments demonstrate that linoleic acid is absorbed by a concentration-dependent dual mechanism of transport. The absorption rate is modified by the pH, surfactant type and concentration, the simultaneous presence of other polyunsaturated fatty acids, and the thickness of the unstirred water layer.

Animals↗