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Biomedical subjects

J Lewis

Publications and source records attributed to J Lewis.

At least 433 records · Page 24Linked to original sources
PubMed1977

Influence of lipid concentrations and age on transfer of plasma lipoprotein into human arterial intima.

Transfer of low-density lipoprotein (L.D.L.2) from plasma to arterial intima was studied in 16 patients undergoing arterial surgery. Autologous labelled lipoprotein was used to demonstrate that L.D.L.2 enters the intima from plasma. Net flux of L.D.L.2 appeared to increase with age. Within each age-group the net flux of L.D.L.2 showed a pronounced positive correlation with plasma-L.D.L.-cholesterol concentrations. This may account in part for the association between hypercholesterolaemia and the development of atherosclerosis.

Adult↗
PubMed1977

Detection of canine Batten disease with the EEG.

Although it has been suggested that EEG changes appear early in the course of human Batten disease, these observations have been made only after the onset of clinical abnormalities and without immediate pathological correlation. In this brief report we have been able to document for the first time, abnormal EEGs in a strain of dogs proposed as a model for Batten disease. The degree of abnormality in the canine EEG correlated with the degree of clinical involvement and with the presence of pathological inclusions, resembling those seen in human Batten disease. In younger dogs, abnormal EEGs were obtained even before clinical manifestations of the disease. The large amplitude discharges reported with photic stimulation in children with the late infantile form of Batten disease were not elicited in the dog model. However, this dog strain is a model for the juvenile rather than the late infantile form although similarities between dogs and both forms of human Batten disease were seen. It is proposed that the EEG is both a method for early detection of this disease as well as a tool ot measure the degree of involvement. This information may be of use in relation to future therapeutic trials.

Animals↗
PubMed1977

Acrosyringeal nevus.

Explore the source record for details and available documents.

Adenoma, Sweat Gland↗
PubMed1977

Pulmonary tissue concentrations of ethchlorvynol after intravenous injection.

Noncardiogenic pulmonary edema has been reported to follow the intravenous use of ethchlorvynol (Placidyl) in both human clinical and animal experimental situations. In a further attempt to define ethchlorvynol-pulmonary tissue inter-relations, we measured ethchlorvynol concentrations in venous and arterial blood and lung and liver tissue of dogs after intravenous injection of 15 to 25 mg of the drug per kg of body weight. In 10 dogs, the mean +/- SEM lung concentrations 1, 3, and 5 min after injection were 70 +/- 20, 50 +/- 13, and 24 +/- 9 mug per g of tissue, respectively. Simultaneous mean +/- SEM venous contrations were 75 +/- 40, 29+/-5, and 22 +/- 5 mug per ml of blood, respectively. During minutes 1 and 3, the liver concentrations were lower than those found in the lung. In an additional 3 dogs, injection of ethchlorvynol into the portal vein led to higher concentrations (at all sample times) in the liver when compared to the lung. In vitro lung slice studies using ethchlorvynol labeled with iodine-131 revealed no active energy-dependent uptake. Intravenously administered ethchlorvynol rapidly fluxes into and out of lung tissue, apparently following the laws of diffusion.

Animals↗
PubMed1977

The effects of ethchlorvynol on pulmonary alveolar membrane permeability.

Intravenous injection of ethchlorvynol (Placidyl) causes noncardiogenic pulmonary edema in humans and laboratory animals. We studied the effects of intravenous ethchlorvynol (15 to 25 mg per kg of body weight) on pulmonary alveolar membrane permeability to various endogenous and exogenous solutes in the in vivo saline-filled dog lung model. Baseline and postethchlorvynol times in minutes for 50 per cent equilibration between the blood and saline-filled alveoli were, respectively, for urea, 37.3 +/- 12.4 and 12 +/- 6.3; for albumin 8,160 +/- 4,400 and 267 +/- 93; for dextrans of molecular weight 10,400 daltons, 1,150 +/- 80 and 185 +/- 160; for dextrans of molecular weight 250,000 daltons, 24,000 +/- 800 and 1,120 +/- 900; for dextrans of molecular weight 500,000 daltons, 24,500 +/- 150 and 1,020 +/- 590. All of these pairs of values were significantly different (P less than 0.01). In addition, lung liquid histamine (but not blood histamine) concentrations increased significantly (P less than 0.001) after ethchlorvynol injection. Intravenous ethchlorvynol causes marked increases in alveolar membrane permeability.

Animals↗
PubMed1977

The renal handling of parathyroid hormone. Role of peritubular uptake and glomerular filtration.

The mechanisms of uptake of parathyroid hormone (PTH) by the kidney was studied in anesthetized dogs before and after ureteral ligation. During constant infusion of bovine PTH (b-PTH 1-84), the renal arteriovenous (A-V) difference for immunoreactive PTH (i-PTH) was 22+/-2%. After ureteral ligation and no change in renal plasma flow, A-V i-PTH fell to 15+/-1% (P < 0.01), indicating continued and significant uptake of i-PTH at peritubular sites and a lesser role of glomerular filtration (GF) in the renal uptake of i-PTH. Since, under normal conditions, minimal i-PTH appears in the final urine, the contribution of GF and subsequent tubular reabsorption was further examined in isolated perfused dog kidneys before and after inhibition of tubular reabsorption by potassium cyanide. Urinary i-PTH per 100 ml GF rose from 8+/-4 ng/min (control) to 170+/-45 ng/min after potassium cyanide. Thus, i-PTH is normally filtered and reabsorbed by the tubular cells. The physiological role of these two mechanisms of renal PTH uptake was examined by giving single injections of b-PTH 1-84 or synthetic b-PTH 1-34 in the presence of established ureteral ligation. After injection of b-PTH 1-84, renal A-V i-PTH was 20% only while biologically active intact PTH was present (15-20 min). No peritubular uptake of carboxyl terminal PTH fragments was demonstrable. In contrast, after injection of synthetic b-PTH 1-34, renal extraction of N-terminal i-PTH after ureteral ligation (which was 13.4+/-0.6% vs. 19.6+/-0.9% in controls) continued for as long as i-PTH persisted in the circulation. These studies indicate that both GF and peritubular uptake are important mechanisms for renal PTH uptake. Renal uptake of carboxyl terminal fragments of PTH is dependent exclusively upon GF and tubular reabsorption, whereas peritubular uptake can only be demonstrated for biologically active b-PTH 1-84 and synthetic b-PTH 1-34.

Animals↗
PubMed1977

Neonatal treatment with sex steroids: relationship between the uterotropic response and the estrogen "receptor" in prepubertal rats.

We tested the hypothesis that neonatal treatment of rats with testosterone propionate (TP) or estradiol benzoate (EB) reduces the uterine responsiveness to estradiol and reduces the concentration of estrogen "receptor" before puberty, and that both of these events precede the onset of the persistent estrus syndrome. Thre-day-old female rats were injected with 100 mug EB, TP or sesame oil (controls) and at 23 and 31 days of age (before the onset of puberty) the uterine cytoplasmic content of specific 8S estradiol-binding protein was measured by sucrose density gradients. Binding by the nuclear fraction was also measured utilizing an exchange assay. In a subgroup of rats also treated neonatally, 2 mug/kg body weight estradiol-17beta was injected at 22 and 30 days of age and uterine wiights were measured as a test for uterine responsiveness. At 23 and 31 days of age the uterine cytoplasmic 8S estrogen "receptor" was significantly reduced in the EB-treated rats, but the uterotropic response to estradiol was blocked only in the 23 day old rats; the uterine response at 31 days was slightly, but not significantly, reduced. In contrast, neonatally administered TP had no effect on either the concentration of cytoplasmic estradiol-binding sites or uterine responsiveness. Nuclear binding of estradiol was unaffected by either TP or EB treatment in both age groups. In a futher experiment in rats ovariectomized at 9 days of age, those treated neonatally with EB had significantly smaller uteri than their untreated ovariectomized controls, thus providing indirect evidence for an extravarian factor affected by neonatal treatment. These data support the hypothesis that neonatal EB treatment may directly inhibit the synthesis or replenishment of the 8S estradiol "receptor" prior to the development of the persistent estrus syndrome (persistent vaginal estrus, anovulation and polycystic ovaries). A neonatally-induced neuroendocrine disorder affecting steroid secretion by the ovary or adrenal may also exist prepubertally to account for the uterine defects.

Aging↗
PubMed1976

Associative elaboration and integration scales for evaluating TAT protocols.

An Associative Elaboration Scale and an Integration Scale were constructed for evaluating Thematic Apperception Test (TAT) protocols. Interrater reliabilities and the correlation between the two scales were determined for a selection of TAT cards. The Integration Scale was dropped from further analyses, because its interrater reliabilities were low and it correlated highly with the Associative Elaboration Scale. The relation between the Associative Elaboration Scale and age was then investigated for randomly selected patients aged 7, 9, 11, 13, and 15. There tended to be a rapid increase in Associative Elaboration scores up to age 11 and then little or no increase in scores. There was no significant relation between Associative Elaboration and IQ.

Adolescent↗
PubMed1976

Eosinophilic cholecystitis.

A somewhat obese, 40-year old female presented with a classic history of gallbladder disease and a peripheral eosinophilia of 14% without an allergic history. A nonvisualizing oral cholecystogram was followed by an uneventful cholecystectomy. Pathological examination revealed a calculus in the cystic duct and a pure transmural eosinophilic infiltrate of the gallbladder wall. Postoperatively the peripheral eosinophilia returned to normal. Biopsies of the small bowel one year later showed focal mucosal eosinophilia when the patient had recurrent abdominal pain, diarrhea and peripheral eosinophilia. Eosinophilic cholecystitis may represent a descrete entity in search of an etiology or involvement of the biliary tract by eosinophilic gastroenteritis.

Adult↗