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Biomedical subjects

L Lewis

Publications and source records attributed to L Lewis.

At least 91 records · Page 5Linked to original sources
PubMed1989

Angiotensin II-producing enzyme III from acidified serum of nephrectomized dogs. Activation of proenzyme III to enzyme III by cathepsin G.

Enzyme III and its inactive precursor proenzyme III have been obtained from the acidified serum of bilaterally nephrectomized dogs. Enzyme III occurs in a concentration producing angiotensin at a rate 50 times higher than the residual renin. Much higher concentrations of enzyme III have been obtained by three activation procedures: a) by storage for several months in the frozen state; b) by treatment at 0 degrees C and pH 3.0; or c) by incubation at 38 degrees C and pH 7.7. These procedures yielded levels of enzyme III that produced up to 400 ng angiotensin II/mL serum/h, i.e., 4000 times higher than the endogenous renin. Of further significance, the angiotensin II produced by enzyme III represents the octapeptide with the highest known vasoconstrictor activity. This is in contrast to renin, enzyme I, and enzyme II, all of which produced angiotensin I, the decapeptide without appreciable vasoconstrictor activity. The endogenous activating enzyme has been identified as cathepsin G by the following six experimental observations: both the endogenous activating enzyme and exogenous cathepsin G produced enzyme III from proenzyme III according to the same unusual sigmoid kinetics; they were blocked identically by antibody to human cathepsin G. Also, both were inhibited similarly by alpha-1-antitrypsin, lima bean trypsin inhibitor, diisopropyl fluorophosphate, or by an inhibitor present in dog serum. Thus, removal of this inhibitor and activation of proenzyme III by endogenous or by added cathepsin G are prerequisites to obtaining enzyme III; this provides a novel mechanism for the rapid formation of angiotensin II from serum protein substrate or from angiotensin I.

Angiotensin II↗
PubMed1988

Expression of polymorphic B-cell antigens on human kidneys.

We have examined the expression on a panel of 22 human kidneys of polymorphic B-cell determinants recognized by mouse monoclonal antibodies. Monoclonal antibodies from a mouse immunized with an antigenic preparation from a DR4 positive B-cell line reacted preferentially with kidneys from DR4 positive donors (p less than 0.005), and the pattern of reactivity with kidney tissues was similar to that of antibodies to monomorphic determinants of class II. However, these antibodies did not show clear specificity for DR4 on lymphocytes in standard serological analyses. These results provide evidence for the expression of polymorphic class II determinants on human kidneys. Reasons for the differences in the apparent specificities of the monoclonal antibodies when tested on kidney sections and lymphocytes are discussed.

Absorption↗
PubMed1988

Exit interview data: what can it tell management about recruitment and retention patterns?

Two hundred and fifty-one registered nurses who left a major teaching hospital during a three year period from May 1984 to April 1987, completed a questionnaire which sought information on their period of employment and reasons for leaving. The most common work related reasons given by registered nurses for leaving, were excessive workload and inflexible rostering practices. They also perceived positive interpersonal relationships among staff as the single most satisfying factor about the work environment. Management and staff based initiatives are suggested in order to minimise work related reasons for registered nurse turnover.

Adult↗
PubMed1987

Distribution of multiple centrospheres determines migration of BHK syncitia.

After fusion of BHK cells with polyethylene glycol, the resulting syncitia contained in 77% of the cases multiple microtubule organizing centers (MTOCs), which were aggregated into a common centrosphere. Based on the observation of phagokinetic tracks, we found that the syncitia were able to locomote if the MTOCs aggregated into a common centrosphere cluster, and the clustered centrospheres were excluded from the cluster of nuclei of the syncitium. The results suggest that each individual pair of one nucleus and one centrosphere contributes, in a process of vectorial addition, its individual polarity to the polarity of the syncitium. Thus the widely accepted idea that the centrosphere is involved in the determination of cell polarity can be generalized beyond the case of single cells.

Animals↗
PubMed1987

Skeletal muscle creatine kinase MB alterations in women marathon runners.

Total creatine kinase (CK) and CK MB activities were determined in gastrocnemius muscle and serum obtained from 14 female marathon runners. The level of CK MB in muscle increased significantly (p less than 0.05) after chronic exercise training from 5.3% to 10.5% of the total CK activity, but not after acute exercise (post-marathon 8.9%). No significant differences in total CK activities were detected. However, the total CK activity in the muscles were significantly (p less than 0.05) less than those previously reported from the muscle of men runners (1800 U/g, 3000 U/g respectively). No significant correlation existed between fiber type and muscle CK MB activity. Additionally, trace amounts of mitochondrial CK and CK BB were present in muscle homogenates. A significant correlation was observed in the increase in mean serum total CK (597 UL-1) and CK MB (23 UL-1) activities 24 h after the race (r = 0.97, p less than 0.05). These results suggest that gastrocnemius muscle in women adapts to training with increased CK MB activities and imply that skeletal muscle is the major source of elevated serum CK MB activities in women marathon runners.

Adult↗
PubMed1987

A prospective randomized study of the aggressive management of early labor.

The aggressive management of early labor has been suggested as a means to lower the cesarean section rate for dystocia. The aim of our study was to prospectively evaluate a protocol of early intervention in primigravid women with infrequent uterine contractions during early labor in relation to the course of labor, the cesarean section rate, and the perinatal morbidity. In our population the active management of labor did not alter the mode of delivery or the perinatal outcome. Furthermore, the course and duration of labor were not significantly different between the management and control groups.

Adult↗
PubMed1987

Multiple aortic tears treated by primary suture repair.

Blunt trauma to the chest with aortic tear is not an unusual sequela of rapid deceleration. Multiple aortic tears in a viable patient are unusual. A case is reported where multiple aortic lacerations were repaired without the use of prosthetic material. The use of a primary suture repair of aortic injuries is advocated for simple aortic tears not extending proximally to the arch whether they be single or multiple.

Aorta, Thoracic↗
PubMed1987

The reorganization of microtubules and microfilaments in differentiating keratinocytes.

Using immunofluorescence techniques, we have examined the microtubules and microfilaments in colonies of terminally differentiating human keratinocytes in tissue culture. The undifferentiated keratinocytes contained numerous microtubules, which radiated from a centrosomal organization center (MTOC). Differentiating keratinocytes, which leave the basal layer and begin to synthesize involucrin, displayed an altered cytoskeleton. Thick mats and coils of microtubules formed throughout the cytoplasm of the differentiated squames, and microfilaments were no longer visible after staining with phalloidin. Instead, only scattered stipples of phalloidin-stained material were observed. The results suggest that the terminal differentiation of epidermal cells involves a reorganization not only of the keratin filaments but of the entire cytoskeleton.

Actin Cytoskeleton↗
PubMed1986

Correlations between SAT scores and MCAT scores of black students in a summer program.

The purpose of the study reported here was to determine the relationship between Scholastic Aptitude Test (SAT) scores and Medical College Admission Test (MCAT) scores of black students who had participated in a summer program for minority students interested in health careers held at the Medical College of Georgia. A significant correlation was established between these students' SAT and MCAT scores. These findings suggest that students who are likely to perform well in medical school can be selected for medical school while they are still underclassmen, accepted conditionally, and admitted after completing a prescribed curriculum. Early selection has implications for increasing the number of minority students in medicine and for permitting more liberal arts in the premedical education than the present selection process.

Black or African American↗
PubMed1984

Interpretive psychotherapy in the inpatient community meeting.

The purpose of the psychiatric inpatient unit community meeting is often unclear to the staff and patients present (Kisch et al. 1981). We shall suggest a clear psychotherapeutic purpose--that it be a place where staff members provide patients with the opportunity to become aware of fixed, stereotypical meanings that they, the patients, collectively give to the behavior, motives, and attitudes of other people. The means to this end is "here-and-now" transference interpretation of a particular type. This interpretation should be focused on the patients' resistance to the articulation of their implicit attitudes toward the staff. Particularly important is the interpretation of the resistance to the discussion of certain staff-related events and the explication of the meanings patients have given to those events. Such resistance usually takes the form of displacement and identification.

Displacement, Psychological↗
PubMed1982

The relationship of fibroblast translocations to cell morphology and stress fibre density.

Translocation of human fibroblasts in culture was studied using techniques of time-lapse cinemicrography, indirect immunofluorescence, and computer analysis. An inverse relationship between the velocity of cells during the last hour of life and the density of stress fibers seen by immune staining was demonstrated. Translocating cells generally assumed one of two interconvertible morphologies: a triangular tailed shape or tailed fibroblast (TF), and a tailless form that resembled a half-moon, which we call a half-moon fibroblast (HMF). The tail of TFs formed only on regions of substrate that had been previously traversed by cells. The half-moon morphology developed either on previously used or on virgin substrate. Cells adopted the HMF rather than the TF morphology with a four-fold greater frequency. HMFs translocated slightly faster than TFs. The foregoing observation suggest that the fibroblast tail is not an organelle essential for translocation. Since our technique allowed us to distinguish between cells which were cycling and those which had left cycle, we compared their velocities and found them to be similar. Also the average velocities of cells of different population-doubling levels (10th, 30th, 40th) were approximately equal.

Cell Division↗
PubMed1981

Selective versus standard hyperalimentation. A randomized prospective study.

Fifty consecutive surgical patients were included in a randomized prospective study to determine the relative advantages and disadvantages of two types of nutritional support systems: one, selective hyperalimentation, relies on a balanced substrate formula, while the other, standard hyperalimentation, depends on carbohydrate and protein to satisfy the energy requirements of the patient. The patients who received the balanced substrate formula had significantly fewer complications than those receiving standard hyperalimentation, even though both groups achieved positive energy and nitrogen balance. The enhanced safety of selective hyperalimentation suggests its therapeutic superiority as a basic nutritional support system for a busy surgical service.

Glucose↗
PubMed1980

Effect of tunicamycin and cycloheximide on the secretion of acid hydrolases from I-cell cultured fibroblasts.

I-cell cultures fibroblasts secrete excessive amounts of N-acetyl-beta-D-hexosaminidase and alpha-L-fucosidase into the culture media as compared with normal fibroblasts. Addition of tunicamycin or cyd [14C]leucine (40--50%) into trichloroacetic acid-precipitable material decreased the secretion of these I-cell hydrolases to normal values within 24 h, but had no effect on the secretion of acid hydrolases from normal fibroblasts. These results indicate that I-cell cultured fibroblasts secrete at least two types of acid hydrolases: one is tunicamycin- and cycloheximide-sensitive and constitutes the greater proportion of the secreted hydrolases, and a smaller proportion is insensitive to tunicamycin and cycloheximide, similar t9 the acid hydrolases secreted by normal cultured fibroblasts.

Cells, Cultured↗