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Biomedical subjects

W Clark

Publications and source records attributed to W Clark.

At least 109 records · Page 6Linked to original sources
PubMed1978

Functional properties of EL-4 tumor cells with lipid-altered membranes.

The effect of fatty acid substitution of membrane phosphatides on a number of surface-mediated phenomena in EL-4 cells was examined. Tumor cells were grown in the presence of fatty acids that could be expected, on the basis of their physical properties, either to stiffen or fluidize the plasma membrane. Substitution of EL-4 cell membrane phosphatides with as much as 74% nonadecanoic acid (19:0) had no effect on either conjugation with effector cells or subsequent cytolysis by the effector cells. Substitution with linolenic acid (18:3) or elaidic acid (18:1trans) likewise affected neither conjugation nor cytolysis. Substitution with these fatty acids also had no effect on the susceptibility of EL-4 cells to cytolysis by antibody plus complement. On the other hand, the rate of patching of H-2 surface antigens was very sensitive to substitution by both 19:0 and 18:3. Although not conclusive, these results suggest that alterations of the fluid state of the membrane that affect lateral movements of surface proteins may not affect cytolytic processes.

Animals↗
PubMed1978

Alteration of the fatty acid composition of membrane phospholipids in mouse lymphoid cells.

A simple method is described for introducing exogenous fatty acids into the membrane phospholipids of the murine leukemia cell EL-4, and into the membrane phospholipids of resting mouse lymphocytes. The method involves culturing of the cells with free or methylated fatty acids at concentrations up to 50 microgram/ml. The presence of serum in the culture medium does not interfere with fatty acid uptake, but does increase the growth rate and viability of the cells. Membrane lipid composition returns to normal after the cells are grown in medium without exogenous fatty acid. Fractionation of the cell membranes confirmed that exogenous fatty acids were incorporated into the phospholipids of the plasma membrane.

Animals↗
PubMed1977

A rational approach to the surgical management of melanoma.

Our experience with 294 regional lymph node dissections in 250 patients are reviewed. The relationship between the Clark's level of invasion and the thickness of the primary is related to regional lymph node metastases. Patients with Clark's Level III melanoma had a 29% incidence of regional lymph node metastases, Clark's Level IV had a 42% incidence of regional lymph node metastases and Clark's Level V a 58% incidence of regional lymph node metastases. Primary melanomas greater than 1.5 mm in thickness had a 38% incidence of positive regional lymph nodes. We therefore recommend a regional lymphadenectomy in patients with Clark's Levels III, IV and V and all melanomas that are greater than 1.5 mm in thickness. A new technique is described which is helpful in localizing the direction of ambiguous lymphatic drainage in patients with truncal melanoma. The use of radioactive colloidal gold scanning has been useful in predicting lymphatic shed in these ambiguous truncal melanomas. Certain technical aspects of inguinal lymph node dissection are emphasized in an attempt to reduce the morbidity of these dissections. It is emphasized that iliac-obturator lymph node dissections are not performed unless the inguinal lymph nodes are found to be involved by frozen section examination at the time of surgery.

Female↗
PubMed1977

Temporal requirement for antigen in primary and secondary MLC reactions.

The requirement for antigen in primary and secondary mixed leukocyte culture was tested by removal of stimulating cells at various time points with antiserum plus complement. In the primary mixed leukocyte cultures, antigen was absolutely required for 24 hr and the need for antigen diminished essentially completely by 72 hr. In the primary mixed leukocyte culture, the antigen was required only for 6 to 9 hr. These findings are compared with other known parameters of in vitro generation of cytotoxic effector cells.

Animals↗
PubMed1976

Regional lymph node metastases and the level of invasion of primary melanoma.

One hundred and nineteen patients with primary malignant melanoma had their primary lesion classified according to Clark's level of invasion by Clark and the Division of Surgical Pathology at UCLA. Thirty patients had superficial melanoma (Level II) and did not undergo regional lymph node dissection (RLND). All other patients (Levels III, IV, and V) underwent regional lymph node dissection. Thirty-two percent of patients with Level III melanoma, 67% of patients with Level IV melanoma, and 66% of patients with Level V melanoma had metastases to the regional lymph nodes. These studies suggest that the level of invasion, or the thickness of the primary melanoma, is helpful for predicting regional lymph node metastases.

Female↗
PubMed1974

Control of experimental diabetes mellitus in rats by transplantation of fetal pancreases.

Experimental diabetes mellitus in young adult Lewis rats was successfully treated by transplantation of fetal pancreases from syngeneic fetuses. Complete or partial control lasting up to 165 days was achieved in 64 percent of recipients by using two to three pancreases of fetal age (15 to 18(1/2) days) placed under each kidney capsule. Islets of Langerhans without exocrine elements were present in the transplants.

Animals↗
PubMedDate not supplied

Alcoholism: a challenging physician-patient encounter.

Physicians can be most helpful to alcoholic patients, whatever the stage of progression of their illness, by adopting the following strategies: 1. Become familiar with the interactional dynamics that result from denial so as to improve data gathering and interpretation, resulting in better diagnostic acumen. Expect to feel uncomfortable because of the interpersonal nature of alcoholism's defenses. Tolerate these feelings through helping the patient to see how uncomfortable he is because of the illness. 2. Adopt a nonjudgmental stance regarding the complex origins of the problem, and develop the skills to communicate respect and compassion to people who feel demoralized, ashamed, afraid, depressed, and hopeless. 3. Support and encourage the patient in surmounting the obstacles to accepting each day the responsibility for participating in whichever form of treatment fits his or her stage of the illness. 4. Refuse to give up on the patient, unless the patient manifests irreversible cognitive impairments that preclude participation in active treatment for alcoholism.

Alcoholism↗