Search PubMed⌕ Search

Biomedical subjects

B A Neilan

Publications and source records attributed to B A Neilan.

At least 73 records · Page 4Linked to original sources
PubMed1985

Clinical oncology assistantship program for medical students.

The Clinical Oncology Assistantship Program has been offered to approximately 16 sophomore medical students each year at the University of Arkansas for Medical Sciences since 1975. This is an elective, 10-week program given during the summer recess. In the first week of the program, core lectures are given by a multidisciplinary team of cancer educators affiliated with the University of Arkansas. Following this, students spend nine weeks rotating through medical, surgical, and pediatric oncology services of the University of Arkansas for Medical Sciences. In addition, they spend several hours during the program participating in self-directed learning activities at the university's Cancer Teaching Center. The program has been well received by the students, and each year all of the available positions have been filled. Responses on a follow-up questionnaire sent in July 1983 to past participants showed that they continued to rate the program highly. Moreover, 78 percent of the respondents felt the program had influenced positively their attitude toward cancer patients.

Arkansas↗
PubMed1985

Cancer in the elderly: basic science and clinical aspects.

The incidence of cancer increases progressively with age. Rearrangements of genomes have been found to accompany cellular aging. These factors, in concert with age-dependent alterations in immune function and host defense, may help to explain the increased risk of malignant disease in aged persons. The clinical presentation and natural history of neoplasia are also affected by aging. This conference reviews recent developments in these areas, examines the effects of drug use in the elderly and implications for management, and discusses current information on how age may influence the response of cancer to therapy.

Aged↗
PubMed1983

Effect of low-level lead exposure on antibody-dependent and natural killer cell-mediated cytotoxicity.

Splenic antibody-dependent, cell-mediated cytotoxicity against chicken red blood cell targets [ADCC (CRBC)] and natural killer cell-mediated cytotoxicity (NKMC) were determined in C57BL/6 mice given 1300 ppm lead acetate (827 ppm lead) in their drinking water for 8 weeks. ADCC in lead exposed mice was significantly lower than controls at effector to target cell ratios of 100:1, 50:1, and 25:1. In contrast, no significant difference in unstimulated NKMC was seen in lead exposed mice and control mice at effector to target cell ratios of 200:1, 100:1, and 50:1. Moreover, in vivo poly I:C-enhanced NKMC in lead-treated mice was similar to controls at an effector to target cell ratio of 200:1. Blood lead levels averaged 40.5 +/- 1.2 micrograms% in lead-exposed mice and 1.9 +/- 0.3 micrograms% in controls. These findings suggest that chronic low-level lead exposure in mice results in significant suppression of ADCC (CRBC) but does not alter natural killer activity.

Animals↗
PubMed1983

Cancer chemotherapy. Current status, coming innovations.

A wide number of agents are now available for chemotherapeutic treatment of cancer. The agents fall into four categories: the alkylating agents, the antimetabolites, the anti-tumor antibiotics, and the mitotic inhibitors. Various combinations of the agents are used to gain greater treatment efficacy and reduce resistance, and chemotherapy used as an adjunct to surgery can give added benefit in some cases. Since successful chemotherapy depends on using active drugs, new assays to predict drug responsiveness are being developed. Toxicity of cytotoxic drugs remains a major problem, although attempts at modification hold promise. Clinical trials, the mainstay for evaluating efficacy and toxicity of chemotherapy, must be carefully analyzed to interpret results meaningfully.

Alkylating Agents↗
PubMed1983

Natural cell-mediated cytotoxicity in cutaneous T-cell lymphomas.

Natural cell-mediated cytotoxicity was studied in 24 patients with cutaneous T-cell lymphomas and in 18 age- and sex-matched controls studied concomitantly. Percent cytotoxicity was determined by 4-h 51Cr release assay using K562 targets at effector to target ratios of 100:1, 50:1, and 25:1. Mean percent cytotoxicity was significantly lower in patients than in controls at an effector to target cell ration of 100:1. Likewise, decreased cytotoxicity was found at effector to target ratios of 50:1 and 25:1, although this difference was not significant. When natural killer activity was analyzed separately for males and females, cytotoxicity was lower in both, although the decrease was significant only for male patients. Impairment of natural killer activity did not correlate with blood zinc levels, but appeared to correlate with stage of disease.

Adult↗
PubMed1983

Hyposplenism in systemic lupus erythematosus.

Splenic function as measured by number of vacuolated red blood cells (RBC) seen with phase contrast microscopy was studied in 44 patients with systemic lupus erythematosus (SLE). Two of 44 patients (4.6%) had increased percentages of vacuolated RBC (8.4% and 30.6%) indicative of hyposplenism. Both patients had inactive disease at the time, were on low doses of corticosteroids, and had persistence of vacuolated RBC when restudied 2 and 4 months later. The present study confirms the association of hyposplenism with SLE and indicates that the incidence of hyposplenism in SLE is about 5%.

Adolescent↗
PubMed1983

Metastatic spinal cord compression.

Spinal cord compression from metastatic cancer is a medical emergency. Prompt intervention affords the best chance for successful recovery, while delay may result in devastating neurologic impairment. In the appropriate clinical setting, emergency myelography should be done to confirm the diagnosis of metastatic disease. Dexamethasone should then be started, followed by immediate radiation therapy or surgical decompression.

Dexamethasone↗
PubMed1981

Heparin kinetics: variables related to disposition and dosage.

A method to determine heparin kinetics and dosage requirements was examined in 20 patients with active thromboembolic disease. Pretreatment heparin sensitivities were determined to establish the relationship between heparin concentration and activated partial thromboplastin times (APTTs). After an initial bolus dose, serial APTTs were measured, heparin concentrations were estimated, and kinetic determinations followed. Heparin elimination rate, distribution volume, and clearance were used to calculate dosage requirements. There was a 500% range in pretreatment heparin sensitivities. Smokers had more rapid heparin elimination rates and t 1/2s than nonsmokers did. Men had more rapid drug clearances than women did. Body weight was related to heparin dosage requirements. Patients treated early after onset of symptoms required higher doses than patients in whom treatment was delayed. A multiple regression model was developed for heparin dosage requirements from body weight, sex, delay between onset of symptoms and treatment, and smoking. This statistical model explained 78% of the variance in heparin requirements.

Adolescent↗
PubMed1980

Persistence of vacuolated RBCs after splenectomy in adults.

Children undergoing splenectomy after trauma commonly have few vacuolated RBCs, suggesting a recurrence of splenic activity. We assayed RBCs with vacuoles in 17 adults who had splenectomies for trauma and 15 adults who underwent splenectomy for nontraumatic indications. Vacuolated cells averaged 29.0% +/- 1.0% (SE) in adults having emergency splenectomies and 32.3% +/- 2.0% in those having elective splenectomies. One adult who had a splenectomy for trauma had few RBCs with vacuoles, and a technetium Tc 99m sulfur colloid spleen scan showed one accessory spleen. These findings suggest that recurrence of splenic activity in adults, unlike in children, is an uncommon sequela of splenic rupture.

Adolescent↗
PubMed1980

Phenytoin and formation of T lymphocyte rosettes.

Phenytoin sodium has been associated with the formation of altered T lymphocyte rosettes in vitro. To investigate the clinical relevance of this observation, the formation of T lymphocyte rosettes in nine patients was studied before treatment with phenytoin and after therapeutic concentrations of the drug in plasma were attained. The percentage of total rosette-forming cells found before treatment was not significantly different from the percentage found 24 hours after treatment. Likewise, the percentage of active rosette-forming cells before phenytoin therapy was not significantly less than after therapy. These results suggest that in vivo treatment with phenytoin does not acutely inhibit the formation of T lymphocyte rosettes.

Adult↗
PubMed1980

Lack of correlation of T and B lymphocytes with stage of colorectal carcinoma.

Total lymphocyte counts and T and B lymphocytes were measured preoperatively in 19 patients with colorectal carcinoma. No correlation between lymphocyte levels and tumor stage was found. It is concluded that enumeration of T and B lymphocytes in adenocarcinoma of the colon or rectum would not be helpful in predicting disease status.

Adenocarcinoma↗
PubMed1980

Late sequelae of splenectomy for trauma.

Hematologic and immunologic changes following splenectomy for trauma include abnormal RBC morphology, leukocytosis, thrombocytosis, impaired clearance of blood-borne particulate antigens, and reduced antibody formation. These abnormalities may be the bases for overwhelming bacterial infection, the most serious delayed complication of splenectomy for trauma. The state of knowledge at present indicates that splenectomized patients should receive pneumococcal vaccination, but whether penicillin prophylaxis should be given daily in addition is less clear. However, penicillin may be advisable for young children, particularly those under 2 years of age, in whom the efficacy of pneumococcal vaccine has not been established. To prevent sepsis, various surgical alternatives to total splenectomy have been proposed, including deliberate autotransplantation of splenic tissue at the time of splenectomy.

Adult↗
PubMed1980

Estimated and determined P50 values in erythrocytosis.

Actual determination of the position of the oxygen-hemoglobin dissociation curve (P50) was compared to three methods of estimating P50 in 20 patients with erythrocytosis. There was a significant correlation between determined and estimated P50 values for each of the methods studied. Furthermore, four patients with high affinity hemoglobins were readily distinguished from the other patients by estimating P50. The data suggest that calculating P50 is reliable and may replace the need for actual measurement.

Adolescent↗
PubMed1980

Decreased T cell function in mice exposed to chronic, low levels of lead.

The immune responsiveness of mice given low levels of lead acetate (1300 p.p.m.) in their drinking water for 8 weeks was determined. Mean percentages of splenic T and B lymphocytes in lead-exposed mice were slightly lower than in controls. Mean mitogen response to phytohaemmaglutinin and concanavalin A in mice exposed to lead was significantly decreased compared to controls. The response to lipopolysaccharide on the other hand was not significantly mitogenic response to phytohaemagglutinin and concanavalin A is impaired in mice exposed chronically to low concentrations of lead.

Animals↗
PubMed1979

Active rosette-forming T cells in the elderly.

The numbers and percentages of active rosette-forming T cells were measured in two age groups, to assess the effects of aging. The study included 21 healthy persons in the 20--40 age group and 25 persons without major disease in the 60--85 age group. In the younger subjects the number of rosette-forming cells (RFC) averaged 1430 +/- 463/cu mm (mean and S.D.), a count not significantly different from that in the older subjects (1443 +/- 398/cu mm). Likewise, the active RFC count in the 20--40 age group (526 +/- 185/cu mm) and that in the 60--85 age group (558 +/- 197/cu mm) were not significantly different. There was no difference for the percentage total RFC (young 78 +/- 4%, elderly 78 +/- 6%) or the percentage active RFC (young 29 +/- 7%, elderly 30 +/- 6%). For the total lymphocyte count or the B lymphocyte count, there was no difference between the two groups of subjects. It is concluded that T lymphocytes, measured as total and active rosette-forming cells, are not decreased in healthy older persons.

Adult↗
PubMed1978

Prevention of chloramine-induced hemolysis in dialyzed patients.

Chloramines, compounds made up of chlorine and ammonia, when present in tap water used for dialysis cause methemoglobinemia and hemolysis. Ascorbic acid addition has been reported to effectively neutralize chloramines in vitro and in patients dialyzed with the single batch dialysis delivery system. We extended these observations to patients dialyzed with the proportioning dialysis delivery system where exposure time of ascorbic acid to chloramines is shorter. This may be important since we found that the half time of the reaction between ascorbic acid and chloramines is 4 minutes. Red cell oxidant sensitivity in 15 patients was assessed by incubating red cells with ascorbate-cyanide and measuring methemoglobin which averaged 2.17 +/- 0.42 g/100 ml (SEM) before dialysis and 2.87 +/- 0.52 g/100 ml after dialysis (NS). Reduced glutathione (GSH) levels were also measured as an index of red cell oxidant damage. GSH decreased from a mean of 7.40 +/- 0.59 micromoles/g Hb before dialysis to 6.98 +/- 0.52 micronmoles/g Hb after dialysis (P less than 0.01). In 2 patients there was no change in 51Cr red cell survival when dialyzed on either the proportioning system or other chloramine free systems. We conclude that addition of ascorbic acid to neutralize chloramines in tap water is also effective when using the proportioning dialysis delivery system.

Adult↗
PubMed1977

T lymphocyte rosette formation after major burns.

The ability of lymphocytes to form rosettes with sheep erythrocytes was studied in the acute burn period to quantitate T lymphocytes. Seventeen adult patients with burns of greater than 15% body surface area were studied serially and compared to normal controls. The absolute number of total rosette-forming cells (RFC) averaged 1,229.1 +/- 92.8/cu mm (SEM) for controls. In patients, a comspicuous decrease in absolute number of total RFC occurred at days 3 to 5 postburn (578.0 +/- 144.2/cu mm) (P less than .001) and during days 6 to 10 (799.8 +/- 106.1/cu mm) (P less than .01). Similarly, the percentage total RFC in patients at days 6 to 10 (48.9% +/- 3.3%) was significantly lower than controls (73.9% +/- 0.7%) (P less than .01). The decrease in total RFC did not correlate with the total lymphocyte count or the cortisol level. These findings suggest that T lymphocytes are decreased or have altered rosette-forming ability in the early postburn period and are in accordance with other reports of impaired cellular immunity following burns.

Adolescent↗