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Biomedical subjects

S Davis

Publications and source records attributed to S Davis.

At least 487 records · Page 27Linked to original sources

Deposition of retrovirus associated antigens (p30 and gp70) on cell membranes of feline and murine leukaemia virus infected cells.

A quantitative estimation of retrovirus associated cell membrane antigens of murine and feline cells infected with their respective type C leukosis virus is presented. Using a radio-immune assay with three broadly reactive antisera, the minimum estimated number of retrovirus associated antigenic determinants on YAC [Moloney leukaemia virus (MuLV) infected murine] and FL-74 [feline leukaemia virus (FeLV) infected feline] cells was 1.3 x 10(6) and 1.6 x10(6) determinants per cell respectively. The virus structural proteins p27-30 and gp70 were detected by three component specific antisera on murine and feline cell surfaces in amounts which varied between cell isolates. MuLV infected cells produced as many as 1.9 x 10(5) p30 antigenic determinants and 7.5 x 10(5) gp70 determinants on infected cells. FeLV infected cells (FL-74) expressed 5.6 x 10(5) p27 and 7.5 x 10(5) gp70 antigenic determinants per single cell surface. The major core protein (p27-30) and the major envelope glycoprotein (gp70) antigens are sufficiently physically separated on cell surfaces so that binding of either of the membrane antigens with component specific antibodies does not interfere with binding of antibodies specific for the other. Despite the expression of interspecies determinants for p30, gp70, and other retrovirus associated antigens detected by antibody procedures, interspecies determinants of cell mediated immunity could not be demonstrated in immune mice bearing Moloney sarcoma virus (MSV) induced tumours. Furthermore, xenogeneic immunization of mice with FL-74 cells failed to protect mice against the growth of MSV induced lymphoma or sarcoma.

Animals↗

Evaluation of pharmacist management of streptococcal throat infections in a health maintenance organization.

A program within a health maintenance organization in which pharmacists were delegated the responsibility of treating and managing adult patients whose throat culture results were positive for group A, beta-hemolytic Streptococcus was evaluated. Results of 50 patients who received diagnostic throat cultures and treatment from internists, physician's assistants and nurse practitioners were compared with results of 58 patients treated and managed by pharmacists who followed procedures defined by physicians. Six hypotheses were tested with respect to the pharmacy program: (1) provider time is saved; (2) the time between throat culture and therapy initiation is shortened; (3) there are fewer return sick visits; (4) there are more reculture follow-up visits; (5) the medication regimen which exhibits a higher rate of cure (oral vs injection) is used more often; and (6) cost savings are realized. Hypotheses 1, 2 and 6 were supported by the results, 3 and 4 were possibly supported, and 5 was not testable. Pharmacists appeared to be as effective as the other practitioners in the management and treatment of streptococcal sore throat.

Adult↗

Chemotherapy for colorectal cancer with a combination of 5-fluorouracil, mitomycin C, adriamycin, and cytosine arabinoside: a pilot study.

Fifty-four patients with clinical evidence of residual colorectal adenocarcinoma following surgical removal of the primary tumor were treated with a combination of 5-fluorouracil, mitomycin C, adriamycin, and cytosine arabinoside. The objective response rate in these patients was 17%. Bone marrow suppression was the major toxic effect. These data fail to show an advantage of this combination therapy over previously described chemotherapeutic regimens.

Adenocarcinoma↗

Primary empty sella syndrome and benign intracranial hypertension.

Two patients presenting with headache and radiological features of an enlarged sella turcica were found to have the primary empty sell syndrome. Whilst under observation, 1 patient developed papilloedema and was shown to have benign intracranial hypertension. The second patient also had raised intracranial pressure. A relationship between the empty sella syndrome and benign intracranial hypertension has previously been reported and it is suggested that in a patient with a congenitally incompetent diaphragma sella, chronically raised intracranial pressure caused herniation of the subarachnoid space into the sella turcica. Subsequently, sella turcica enlargement and remodelling occurs, sometimes with endocrine, visual and other sequelae. The clinical, radiological and CT scan features of the empty sella syndrome are discussed and the indications for major radiological studies are considered.

Adult↗

The variable pattern of circulating lymphocyte subpopulations in chronic lymphocytic leukemia.

The percentages of T and B lymphocytes in 13 patients with chronic lymphocytic leukemia were determined at two-week intervals. One patient with "B-cell predominant" disease showed a decrease from 77 to 49 in the percentage of circulating B cells, which bind heat aggregated immunoglobulin and anti-human immunoglobulin. This patient had a comparable increase in T cells, which form rosettes with sheep erythrocytes. The lymphocytes of three other patients, who originally had equal percentages of cells that bound heat-aggregated immunoglobulin and anti-human immunoglobulin, lost lg determinants from 47 to 63 per cent of cells without changing the proportion of cells with receptors for heat-aggregated immunoglobulin or for sheep erythrocytes. The characterization of lymphocytes in chronic lymphocytic leukemia should include sequential determination of cell-surface markers for both T and B cells, since the disease does not represent a proliferation of B cells alone.

Adolescent↗

Hospital managers need management information systems.

A new hospital director seeking to bring his institution to the brink of solvency found himself with ten pounds of data but no "information"--at least, not the kind of information he could use as a basis for management decisions. What he needed was a system that would not only present data, but the meaning of the data. Such a system is the integrated MIS.

Computers↗

Further characterization of the circulating cell in chronic lymphocytic leukemia.

Peripheral lymphocytes from normal individuals and from patients with chronic lymphocytic leukemia (CLL) were cultured in vitro for 1-7 days. The growth response to phytohemagglutinin (PHA) was quantitated by the incorporation of tritiated uridine into RNA nucleotide during a 2-hr pulse with the radioisotope. While the maximum response in PHA-stimulated normal cultures appeared at 2-3 days, CLL cultures required 5-7 days to develop their maximal response, which was 50%-60% of the normal magnitude. Dilution of the number of normally reactive lymphocytes by culturing them with totally unreactive, mitomycin-treated cells produced a normal 72-hr maximal response, no matter what proportion of unreactive cells was included in the PHA-stimulated cultures. In addition, the response of peripheral lymphocytes from patients with myeloblastic leukemia, where large numbers of unreactive myeloblasts diluted the normal small lymphocytes, a depressed reaction occurred at the anticipated 2-3 days. Nylon fiber-adherent lymphocytes consisting of 85% immunoglobulin (Ig)-bearing cells responded minimally to PHA, but showed no evidence of a delay. When isolated from CLL patients, both fiber-adherent cells (Ig-bearing) as well as non-fiber-adherent (sheep erythrocyterosetting) cells responded to PHA in a delayed fashion. Similarly, a case of CLL, in which 93.5% of the circulating lymphocytes bore sheep red blood cell receptors, showed its peak response to PHA at 7 days. Therefore, using surface marker criteria considered characteristic of normal T cells and B cells, the delayed response to PHA on the part of CLL lymphocytes was independent of thymic or nonthymic origin.

Adult↗

Immune response of monkeys to lymphotrophic herpesvirus antigens.

Herpesvirus saimiri induces leukemia and/or malignant lymphoma when inoculated into different species of nonhuman primates including marmosets and owl monkeys. No malignant disease, however, has been recognized in the natural host for this virus, the squirrel monkey, although a high percentage of these monkeys are chronically infected with H. saimiri. Furthermore, one species of marmosets, as well as capuchin and some owl monkeys, fail to develop lymphoma following experimental virus infection but developed a chronic infection similar to that noted in the natural host. The availability of susceptible and resistant species made it possible to attempt to delineate those humoral and cellular immune parameters that might correlate both with tumor induction and resistance. The findings from these investigations are reviewed and discussed in relation to vaccine studies in this system as a model for a human herpesvirus vaccine.

Animals↗

Energy dose for ventricular defibrillation of children.

Transthoracic direct current shock is the recommended treatment for ventricular fibrillation in children as in adults. To determine the appropriate energy dose, data were collected from 71 defibrillation attempts in 27 children. Sixty-three of the 71 shocks (89%) were successful in terminating fibrillation. Fifty-seven shocks were within 10 watt-seconds (w-sec) above or below an energy dose of 2 w-sec/kg of body weight. Fifty-two (91%) of these were effective and five (9%) were ineffective. In every case, fibrillation was ultimately terminated by a shock of 4 w-sec/kg or less. The results of these studies suggest that an energy dose of 2 w-sec/kg (or approximately 1 w-sec/lb) is adequate to defibrillate most children weighing under 50 kg. We currently use 2 w-sec/kg and double the energy dose if the first defibrillation attempt is unsuccessful.

Adolescent↗

Prehatch color stimulation effects on color pecking preferences and color discrimination learning in white leghorn chicks.

Four experiments assessed the effects of stimulating chick embryos with colored light at 2 intensity levels. Both posthatch color pecking preferences (Experiments 1 and 2) and color discrimination learning (Experiments 3 and 4) were unaffected. These results affirm and extend a prior finding of no pre- and posthatch colored light stimulation effect on posthatch color preferences in ducklings. The color pecking preferences found replicated prior findings with chicks. However, they differed from the approach color preferences observed in color discrimination learning.

Animals↗

Pigmented villo-nodular synovitis: bone involvement of the fingers.

Pigmented villo-nodular synovitis may occur in either diffuse or nodular form. In the latter the fingers are the commonest site to be involved. The disease is rare, and in only 15% is there bone involvement. Two cases showing bone involvement of the fingers are presented. One of the cases (Case 2) adds radiological support to the theory of Scott (1968), based on pathological studies, that suggested that the bone changes are due to invasion by the villo-nodular tissue through and along the nutrient foramina. The site of these bone changes appears sufficiently typical to be a radiological diagnostic aid. The differential diagnosis of the radiological appearances of the disease in the digits is discussed.

Bone Diseases↗

Moloney sarcoma virus-induced tumors in athymic (nude) mice: growth pattern and antibody responses.

Tumor growth and antibody production were evaluated in nude (nu/nu) mice and their heterozygous normal (+/nu) littermates after inoculation of Moloney sarcoma virus (MSV). Sarcoma-bearing nude mice developed progressively growing tumors, whereas 53 percent of their normal counterparts showed tumor regressions. By indirect membrane fluorescence, significant amounts of IgG antibody to MSV could be detected in thymus-bearing but not in nude mice.

Animals↗

Genetic control of the murine cell-mediated immune response in vivo. I. H-2-linked responsiveness to the terpolymer L-glutamic acid-60-L-alanine-30-L-tyrosine-10.

Various inbred and congenic strains of mice were immunized with the linear terpolymer L-glutamic acid-60-L-alanine-30-L-tyrosine-10 (GAT). Using a radioisotopic footpad assay to measure cell-mediated immunity in vivo, mice with H-2-a, H-2-b, H-2-d, and H-2-k histocompatibility alleles showed a positive reaction, whereas mice with H-2p and H-2-s alleles failed to respond. The ability of "responder" lymphocytes to show an immune response resides in the thymus-derived (T) lymphocyte population. Unfractionated spleen cells from H-2-q nonresponder mice, on transfer, showed no reactivity, whereas T-cell-enriched preparations were active.

Alanine↗

Enhancement of Moloney sarcoma virus-induced tumor growth by concanavalin A.

Adult mice injected intraperitoneally with concanavalin A (con-A) commencing with the onset of 6mm. Moloney sarcoma virus (MSV)-induced tumors showed a marked enhancement of tumor growth compared to untreated control mice; whereas, treatment with con-A beginning on day 0 relative to MSV inoculation had no effect. Antibody production as measured by indirect membrane fluorescence was not affected by con-A. Since in vivo administered con-A has a specific suppressive effect on T-lymphocytes it is suggested that the primary immunologic response to MSV antigens is a function of T-cells.

Animals↗