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Biomedical subjects

J R Simpson

Publications and source records attributed to J R Simpson.

At least 73 records · Page 4Linked to original sources
PubMed1990

Primary central nervous system lymphoma: analysis of prognostic variables and patterns of treatment failure.

The authors retrospectively analyzed the data on 36 patients with primary central nervous system (CNS) lymphoma. Most patients received radiation therapy to the whole brain with or without a boost. Chemotherapy was administered to six patients (18%) as part of their initial therapy. The 1- and 2- year rates of progression-free survival were 46% and 27%. The following factors had a favorable impact on survival: age of 60 years or less, normal or mildly impaired preirradiation neurologic function, and confinement of the tumor to the cerebral hemispheres or cerebellum. Chemotherapy as part of initial therapy appears to improve local control. Increasing radiation doses delayed local failure. Failure occurred in the brain (88%), in the eye (23%), and systemically (8%). There were no neuraxis failures identified. The authors conclude that primary CNS lymphoma is a locally aggressive disease that is poorly controlled with conventional radiation therapy. Investigation for more effective therapy is ongoing.

Aged↗
PubMed1990

Lymphocyte subset responses to repeated submaximal exercise in men.

The effects of repeated bouts of submaximal cycle ergometry exercise on changes in the percentage of peripheral blood T-lymphocytes, the T-helper/inducer and T-cytotoxic/suppressor subsets, and natural killer (NK) cells were studied in 18 healthy young men who had no history of regular exercise training. Subjects were matched on the basis of maximal O2 uptake and assigned randomly to exercise or control groups, with controls resting quietly during the exercise sessions. The percentage of peripheral blood mononuclear leukocytes that reacted with monoclonal antibodies specific for T-lymphocytes (CD3+ cells), the helper/inducer subset (CD4+ cells) and cytotoxic/suppressor subset (CD8+ cells) of T-lymphocytes, and cells with NK activity (Leu7+ cells) were enumerated by fluorescence-activated flow cytometry for samples obtained immediately before and after exercise on days 1, 3, and 5 of a 5-day exercise regimen. The results of this study were mixed with decreases in the percentage of T-lymphocytes before vs. after exercise on days 1 and 3 (P less than 0.001), a decrease in the percentage of T-helper/inducer cells before vs. after exercise on day 3 (P less than 0.05), no effect of exercise on the percentage of T-cytotoxic/suppressor cells, and a marked increase in the percentage of NK cells after exercise on days 1 (P less than 0.05) and 3 (P less than 0.01). The total number of recovered NK cells in the mononuclear leukocyte fraction of blood also increased significantly after exercise on days 1 (P less than 0.05) and 3 (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Exercise stress and murine natural killer cell function.

Male C3He mice were trained to run on a treadmill (final speed, slope, and duration of 30 m/min, 8 degrees, 30 min/day, 5 days/week, respectively) for 10 weeks or they remained sedentary. At the end of the training program, half of the mice were sacrificed and half were given a single bout of exercise to exhaustion (50% stepwise increases in final running speed for 2-min intervals). Splenic catecholamine concentrations, splenic natural killer cell cytolytic activity against YAC-1 tumor targets, and frequency of asialo GM1 (a murine natural killer cell surface glycolipid)-positive splenocytes were assessed. Exhaustive exercise in both trained and untrained mice reduced the in vitro killing of tumor targets by splenic natural killer cells relative to killing by splenocytes from mice which did not undergo the acute exercise bout (P less than 0.05). The frequency of asialo GM1-positive splenocytes was also reduced in the exhaustively exercised animals (P less than 0.05). Training alone, without the additional stress of exhaustive exercise, reduced the frequency of asialo GM1-positive splenocytes relative to a sedentary condition (P less than 0.05), but did not compromise natural killer cell cytolytic activity against the tumor targets. Splenic epinephrine concentrations in the exhaustively exercised animals were elevated 3- to 5-fold above the concentrations observed in trained and sedentary mice. These results suggest that a single, acute exercise bout reduces the capacity of splenic natural killer cells to kill tumor targets in vitro and that training enhances splenic natural killer cell cytolytic activity, on a per cell basis, against tumor targets.

Animals↗
PubMed1989

Prognostic factors and results of therapy for adult thalamic and brainstem tumors.

This report is a retrospective analysis of 83 adults (greater than 16 years of age) with histologically proven or presumed primary neoplasms of the thalamus, hypothalamus, midbrain, pons, and medulla. Patients were treated with combined surgery and postoperative irradiation or with irradiation alone at the Washington University Medical Center (St. Louis, MO) from January 1950 through December 1984. Histologic analysis confirmed the diagnosis of tumor in 21, including nine with well-differentiated astrocytoma, four with astrocytoma with anaplasia, and eight with glioblastoma multiforme. Overall and disease-free survivals at 5 years were 28.7 and 23.2%, respectively. A statistical analysis was performed to ascertain the prognostic importance of the following variables: age, race, gender, duration of symptoms, cranial nerve paresis, primary site, extent of surgery, histology, and irradiation dose. The only factor identified by univariate analysis to be critical for survival was primary location of disease. Patients with supratentorial (thalamus/hypothalamus, midbrain) tumors had a 10-year disease-free survival of 15.4% compared to 29.6% for those with infratentorial (pons, medulla) tumors (P = 0.07). Patients with lesions of the pons had a 5-year disease-free survival of 35.8% compared to 13.8% for those with tumors of the thalamus (P = 0.05). Increasing irradiation dose was not correlated with superior survival. Factors evaluated but established to be insignificant were age (P = 0.27), race (P = 0.63), gender (P = 0.27), duration of symptoms (P = 0.19), cranial nerve paresis (P = 0.71), histologic type (P = 0.16), and extent of surgery (P = 0.94). Follow-up for 13 surviving patients ranged from 2.6 to 28.7 (mean, 12.0) years. Neurologic deficits in surviving patients were absent in 15% (two of 13), mild in 62% (eight of 23), and moderate in 23% (three of 13). One case of brain radionecrosis was identified (6000 cGy, 200 cGy daily).

Adolescent↗
PubMed1989

Late regrowth of pituitary adenomas after irradiation and/or surgery. Hazard function analysis.

A retrospective analysis was performed on all patients with pituitary adenomas treated at the Radiation Oncology Center, Mallinckrodt Institute of Radiology, St. Louis, Missouri. Of 210 patients treated from April 1954 through December 1982, 70 were treated with radiotherapy alone (RT), 121 received immediate postoperative RT (2 to 6 weeks), and 19 received RT following surgical failure. The mean follow-up time from the date of diagnosis for those patients alive at the time of last follow-up was 13.0 years (range, 3.0 to 30.0 years). Actuarial progression-free survival was analyzed up to 30 years. The 10-, 20-, and 30-year progression-free survival was 80.5%, 73.5%, and 73.5% for those patients treated with irradiation alone and 92.8%, 71.2%, and 44.0% for those treated with immediate postoperative irradiation. The median time to first failure from initial diagnosis by original treatment was 3.8 years for surgery alone, 4.2 years for RT only, and 10.2 years for surgery plus postoperative RT. Analysis for risk of recurrence per 5-year interval was performed using a hazard function analysis. The risk of recurrence after radiotherapy alone was greatest during the first 5-year interval after treatment and decreased to zero by 20 years. However, the risk of recurrence after primary surgery and postoperative radiotherapy revealed an increasing risk for recurrence up to 30 years after treatment. The concept of "cure" for pituitary adenomas requires extended follow-up.

Actuarial Analysis↗
PubMed1989

Factors influencing outcome of definitive radiotherapy for localized carcinoma of the prostate.

Definitive radiation therapy was administered to 577 patients with histologically confirmed carcinoma of the prostate localized to the pelvis. Results of therapy and prognostic factors are evaluated and compared with other reports. All patients were followed for a minimum of 3 years, the median period of observation is 6.5 years. The disease-free survival in stages A2 and B was 78% at 5 years and 60% at 10 years; in stage C, 60% at 5 years and 36% at 10 years. The overall actuarial survival in stage B patients was 76% at 5 years and 58% at 10 years, which is similar to the life expectancy of a comparable cohort of normal males. In stage C, the actuarial survival was 65% at 5 years and 38% at 10 years, approximately 15% below the normal life expectancy for a similar cohort. Histological differentiation of the tumor had a significant impact on survival, poorly differentiated tumors showing 20% lower survival rates, most likely related to a higher incidence of distant metastases. Age was not found to be a significant prognostic factor in patients with stage B tumors; however, in stage C, the 5-year disease-free survival was 43% in patients younger than 60 and 53% in those older than 60 years (p = 0.04). In stage B, patients who had control of the pelvic tumor exhibited a 80% actuarial 5-year survival and 60% at 10 years. This compares with an actuarial survival of 30% at 5 and 10 years when there was evidence of pelvic recurrence alone or combined with distant metastases. In stage C patients with pelvic tumor control, actuarial survival was 81% at 5 years and 50% at 10 years, in comparison with 20% 5-year and 10% 10-year survival when pelvic recurrence or distant metastases or a combination of both occurred. The method of diagnosis [transurethral resection of the prostate (TURP) versus needle biopsy] did not appear to be a major prognostic factor of survival or patterns of failure, except in patients with stage C moderately differentiated tumors. The interpretation of the lymphangiogram (normal, suspicious or abnormal) did not correlate with survival or tumor control. The pathologic status of the lymph nodes established at lymphadenectomy did not appear to relate to survival for patients with stage B disease.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma↗
PubMed1989

Results of radiotherapy in recurrent endometrial carcinoma: a retrospective analysis of 51 patients.

A retrospective analysis was performed of 51 patients with locoregional recurrence of endometrial carcinoma, treated by radiotherapy between 1959 and 1986. There were 17 patients (33%) with isolated vaginal recurrence, 12 patients (24%) with vaginal recurrence with pelvic extension, 7 patients (14%) with pelvic recurrence only, and 15 patients (29%) with simultaneous locoregional and distant failure. Eighty percent of the recurrences occurred within 3.5 years from primary treatment; time to relapse was shorter in patients with advanced-stage, high-grade malignancy at original diagnosis. Locoregional control was achieved in 18 patients (35%). Complete tumor regression in the vagina, irrespective of extravaginal pelvic disease status or distant metastasis, occurred in 28 of 34 patients with vaginal involvement (82%). The 5- and 10-year overall actuarial survivals for all patients were 18 and 12.5%, respectively. The 5- and 10-year progression-free survivals of patients with isolated vaginal recurrences were 40% and 29%, respectively; the 5-year progression-free survival of patients with vaginal recurrence with pelvic extension was 20%. There were no survivors beyond 1.5 years among patients with pelvic recurrence (p = 0.02). All patients with simultaneous locoregional and distant failure were dead by 3.5 years. Stage at original diagnosis, time to relapse from primary treatment, histologic pattern, and grade of malignancy were prognosticators of survival. Five patients (10%) developed a total of ten radiation-related sequelae.

Aged↗
PubMed1989

Prognostic factors and results of surgery and postoperative irradiation in the management of pituitary adenomas.

Prognostic factors and results of therapy were analyzed in a retrospective examination of 121 patients with pituitary adenomas treated with surgery and postoperative irradiation (RT) from January 1954 through December 1982 at the Radiation Oncology Center, Mallinckrodt Institute of Radiology. The 10-year overall and disease-free survival for all patients was 85.1 and 89.4%. The expected survival for an age-, gender-, and race-matched population was not significantly distinct at 85.3% (p = 0.72). Follow-up of 94 surviving patients ranged from 3.4 to 29.5 years (mean, 11.7). Statistical analysis was performed for multiple prognostic factors including age, race, gender, disease bulk, visual field symptoms, disease type, surgical approach, and irradiation dose and volume. The only prognostic variable identified by univariate analysis to significantly alter disease-free survival was irradiation dose. Patients receiving 5000-5400 cGy had a tumor control rate of 94.1% (64/68) compared to 85.0% (17/20) for 4000-4999 cGy, 75.0% (18/24) for 3000-3999 cGy, and 28.6% (2/7) for less than 3000 cGy (p = 0.000059). Factors evaluated but established to be insignificant were age, race, gender, disease bulk, visual field symptoms, disease type, surgical approach, and irradiated volume. The 10-year disease-free survival by classification was 93.3% for patients with amenorrhea/galactorrhea, 89.9% for non-functioning adenomas, and 76.4% for acromegaly (p = 0.21). Overall improvement in visual field defects subsequent to treatment occurred in 48.4% (44/91) of those with visual field defects before RT and was significantly correlated with RT dose. The median time to progression of disease was 10.2 years with the last failure occurring at 25 years following the fulfillment of RT. Severe complications related to RT were apparent in 1.7% (2/121). None were known to have endured brain radionecrosis. Serious surgical complications occurred in 9.9% (12/121).

Adenoma↗
PubMed1989

Radiation therapy alone or combined with misonidazole in the treatment of locally advanced non-oat cell lung cancer: report of an RTOG prospective randomized trial.

From September 1979 to February 1983, 268 patients with unresectable, locally advanced (RTOG Stage III), non-small cell lung cancer were randomized to receive radiation therapy alone (RT) (50 Gy large field and 10 Gy boost), or combined with misonidazole (400 mg/m2 2-4 hr prior to RT daily for 5-6 weeks to a maximum dose of 12 g/m2 or until tumor progression). One hundred twenty-three patients who received irradiation alone and 116 given RT + misonidazole were evaluable for toxicity, time to tumor progression, and survival as of April 1987. The distribution of patient characteristics was similar in both treatment groups; 59% of the patients had a Karnofsky score of 90 or better, 53% had adenocarcinoma or large cell tumors, and 47% had Stage T3 tumors. Complete tumor regression was reported for 33 (27%) patients treated with radiation therapy alone and 24 (21%) who received misonidazole + RT. Median survival was 8 months with RT alone and 7.4 months with misonidazole + RT. Ninety-five percent of the patients have died. Seventy percent of the patients treated with radiation alone and 77% of those treated with misonidazole + RT died of progressive disease. Three patients treated with radiation alone and two with RT + misonidazole died subsequent to radiotherapy-related pneumonitis or pulmonary fibrosis. There was no significant improvement in response rates, local control, or survival for patients who received daily misonidazole along with irradiation compared with patients treated by irradiation alone.

Adenocarcinoma↗
PubMed1989

Astrocytomas of the cerebellum in children.

Between 1928 and 1980, 84 children (aged 19 years or younger) with an astrocytoma of the cerebellum were managed at Washington University Medical Center-Barnes Hospital. Fifty-eight children were treated with surgery only and 26 received surgery and postoperative irradiation. The 5-, 10-, and 25-year actuarial disease-free survival rates for the entire group were 92%, 88%, and 88%, respectively. Age at diagnosis and extent of surgery were prognostic factors, but no correlation with survival times was found for gross appearance of the tumor or postoperative irradiation. Posttreatment neurological function was excellent in the 58 patients alive at the end of the study; 92% were completely normal or had only a mild neurological deficit and 75% were employed or attending school.

Astrocytoma↗
PubMed1988

Results of surgery and irradiation or irradiation alone for pituitary adenomas.

A retrospective analysis was performed on the clinical course of all patients with pituitary adenomas treated at the Radiation Oncology Center, Mallinckrodt Institute of Radiology, Washington University Medical Center, St. Louis, Missouri. Of 212 patients treated from April 1954 through December 1982, 70 were treated with radiotherapy alone (XRT), 121 began immediate post-operative XRT (2-6 weeks) and 20 received XRT following surgical failure. Several sub-groups of adenomas were identified and analyzed, including secreting versus non-secreting adenomas (33.0% secreting) and by clinical syndrome; 27% with amenorrhea/galactorrhea, 18.4% acromegalic, Cushing's disease in 6.1% and 3.3% with Nelson's syndrome. The median follow-up time from the data of diagnosis for those patients alive at the time of last follow-up was 11.9 years (range 3.0 to 30.0 years). Actuarial overall and disease-free survival was analyzed up to 25 years. The 10-year overall and disease-free survival was 77.8 and 75.3% for those patients treated with XRT alone, 86.4 and 87.2% for those treated with immediate post-operative XRT and 100.0 and 87.5% for those who were irradiated after surgical failure. Complications related directly to XRT occurred in only five patients. One patient had documented central nervous system radionecrosis, two had visual complications, and tumor necrosis with hemorrhage occurred in the other two patients. In conclusion, overall survival for all patients did not significantly differ from an age, sex and race matched population. Control of local disease was greater for those patients receiving surgery and post-operative XRT than for those receiving XRT only. XRT salvage of surgical failures was possible. Treatment with XRT results in a low complication rate.

Adenoma↗
PubMed1988

Prognostic factors and results of radiotherapy alone in the management of pituitary adenomas.

Prognostic factors and results of therapy were analyzed in a retrospective review of 70 patients with pituitary adenomas treated with radiotherapy alone from January 1954 through December 1982 at the Radiation Oncology Center, Mallinckrodt Institute of Radiology. The 10-year overall and disease-free survival was 77.8 and 76.0%. The expected survival for an age-, sex-, and race-matched population was not significantly greater at 87.2%. The 10-year disease-free survival for the distinct tumor types was 100% for Cushing's disease, 82.3% for patients with amenorrhea/galactorrhea, 79.6% for non-functioning adenomas, 69.0% for acromegaly, and 66.7% for Nelson's syndrome. Prognostic variables analyzed were age, race, sex, tumor type, tumor extent, visual field defects at diagnosis, and volume irradiated. Only the presence of visual field defects at diagnosis conferred a poor prognosis (p less than 0.001). There was a tendency toward superior tumor control with radiation doses greater than 4500 cGy (p = 0.15). The median time to progression of disease was 4.2 years, with the last failure occurring at 12 years following the completion of radiotherapy. Severe complications were apparent in 5 patients (7.1%), including one death from central nervous system radionecrosis.

Acromegaly↗
PubMed1988

Long-term results of radiotherapy in the treatment of pituitary adenomas in children and adolescents.

A retrospective review was performed of 11 children and adolescents (less than 19 years of age) with diagnosed pituitary adenomas. The patients were treated with subtotal resection and postoperative irradiation (S + R) or with irradiation alone (RT) at the Radiation Oncology Center, Mallinckrodt Institute of Radiology, Washington University Medical Center, from January 1958 through December 1982. Patient conditions at diagnosis were acromegaly in one, Nelson's syndrome in one, prolactinoma in three, chromophobe adenoma in three, and Cushing's disease in three. Median follow-up was 15.6 years (range 6.3-29.5 years). Only two patients have had failure: one at 8.6 years and the other at 20.7 years following treatment. All four patients with visual field (VF) defects at diagnosis underwent S + R, with only one developing recurrent disease. The remaining seven patients, who did not have VF defects, received RT only, and there has been one failure in this group. None have suffered long-term visual complications. All have been able to continue school and/or work. Three of eight females have borne children. Hypopituitarism requiring medication occurred in all who received S + R and in four of seven who received RT only.

Adenoma↗
PubMed1988

Adenocarcinomas of major and minor salivary gland origin: a histopathologic review of treatment failure patterns.

Fifty-four cases of adenocarcinoma of major and minor salivary gland origin were seen between 1960 and 1980. Fifty of these were treated definitively. Planned surgery combined with radiation was the initial treatment for 22 patients (44%), surgery alone for 15 (30%), and radiation alone for 13 (26%). Of the patients receiving surgery with curative intent, 82% underwent complete resections (i.e., negative margins). Cervical lymph node involvement was present in 23% of cases, and 73% of these patients died of their disease within 3 years. Distant metastases developed in 37% of patients, with a median time of 1 year; 93% of these patients died within 3 years. Histologic grading was performed using objective criteria. Thirty-four percent of tumors were well-differentiated, 27% moderately differentiated, and 39% poorly differentiated. Patients with well-differentiated adenocarcinomas tended to survive disease-free longer and developed fewer distant metastases than those patients with moderately or poorly differentiated tumors.

Actuarial Analysis↗
PubMed1988

Definitive radiation therapy in carcinoma of the prostate localized to the pelvis: experience at the Mallinckrodt Institute of Radiology.

Definitive radiation therapy was administered to 577 patients with histologically confirmed carcinoma of the prostate localized to the pelvis between January 1967 and December 1983. All patients were available for a minimal 3-year follow-up, and the median period of observation is 6.5 years. The actuarial survival without tumor in stages A2 and B at 5 years was 78% and at 10 years 60%. In stage C, the corresponding survival figures were 60% at 5 and 40% at 10 years. The overall actuarial survival in stage B patients was 76% at 5 and 56% at 10 years, which is similar to the life expectancy of a comparable cohort of normal males. In stage C, the actuarial survival was 65% at 5 and 35% at 10 years. The pelvic failure rate in stage A2 was 12% (5 of 41), 17% in stage B (31 of 185), 28% (93 of 328) in stage C, and 48% (11 of 23) in stage D1. Distant metastases were noted in 12% of the patients with stage A2, 20% stage B, 42% stage C, and 65% stage D1. In stage B, patients who had control of the pelvic tumor exhibited an 85% actuarial 5-year survival and a 60% one at 10 years. This compares with an actuarial survival of 30% at 5 and 10 years when there was evidence of pelvic recurrence alone or combined with distant metastases. In stage C patients with pelvic tumor control, actuarial survival was 81% at 5 and 50% at 10 years, in comparison with 25% at 5 and 10% at 10 years when there was development of pelvic recurrence or distant metastases or a combination of both. There was a strong correlation between the survival and appearance of distant metastases with the histologic degree of differentiation of the tumor in all stages. However, the probability of tumor control in the pelvis was not significantly correlated with this parameter. The administration of hormones concomitantly with radiation therapy did not significantly influence the probability of tumor control, appearance of distant metastases, or survival. Major sequelae of therapy were noted in 2.2% of the patients, whereas minor sequelae were observed in approximately 12% of the patients. Radiation therapy has been shown to be an effective therapeutic alternative to radical prostatectomy or hormonal manipulation in patients with carcinoma of the prostate.

Humans↗
PubMed1987

Long-term observations of the patterns of failure in patients with unresectable non-oat cell carcinoma of the lung treated with definitive radiotherapy. Report by the Radiation Therapy Oncology Group.

This report details the patterns of tumor recurrence in two prospective randomized studies involving 551 patients with histologically proven unresectable or medically inoperable non-oat cell carcinoma of the lung treated with definitive radiotherapy. Patients were treated according to two protocols, depending on the stage of the tumor: (1) Patients with T1, 2, 3-NO, 1, 2 tumors were randomized to four different regimens: 4000 cGy split course (2000 cGy in five fractions, per 1 week, 2 weeks rest and additional 2000 cGy in five fractions, per 1 week) or 4000, 5000, or 6000 cGy continuous courses, five fractions per week. (2) Patients with T4, any N or N3, any T stage tumors were randomized to be treated with 3000 cGy tumor dose (TD), ten fractions in 2 weeks, 4000 cGy split course (described above), or 4000 cGy continuous course. In the patients with less advanced tumors (Study 1) the intrathoracic failure rate within the irradiated volume was 48% with 4000 cGy continuous, 38% with 4000 cGy split course or 5000 cGy continuous, and 27% for patients receiving 6000 cGy continuous course. The failure rate in the nonirradiated lung ranged from 25% to 30% in the various groups. Patients with adenocarcinoma or large cell undifferentiated carcinoma had better intrathoracic tumor control (35%) than those with squamous cell carcinoma (20%). The incidence of distant metastases was 75% to 80% in all histologic groups. Distant metastases appeared sooner after therapy in the patients with adenocarcinoma or large cell undifferentiated carcinoma. The initial failure rate in the brain was 7% in patients with squamous cell carcinoma, 19% with adenocarcinoma, and 13% in patients with large cell carcinoma. The ultimate incidence of brain metastases was 16% in squamous cell carcinoma, and 30% for adenocarcinoma or large cell undifferentiated carcinoma. Higher doses of irradiation will be necessary in order to improve the intrathoracic tumor control. Clinical trials by the Radiation Therapy Oncology Group, some of them involving multiple daily fractionation, are in progress. Furthermore, because of the high incidence of distant metastases, effective systemic cytotoxic agents are critically needed to improve survival of lung cancer patients. The high frequency of brain metastases suggests that, as in small cell carcinoma of the lung, elective irradiation of the brain may be necessary, if not to improve survival to enhance the quality of life of patients with adenocarcinoma and large cell carcinoma.

Adenocarcinoma↗
PubMed1987

Mechanisms by which barbiturates suppress lymphocyte responses to phytohaemagglutinin stimulation.

Certain barbiturates (the intermediate- and short-acting drugs) reduce the growth of PHA-stimulated peripheral blood mononuclear cells, but phenobarbitone (a long-acting drug) is ineffective: replicative growth is more sensitive than activation. This action is associated with a marked reduction in the density of interleukin-2 receptors on the cell membrane and of the numbers of cells expressing them, but the growth rate cannot be restored by supplementation of the tissue culture medium with exogenous interleukin-2. The affected cells show swelling of the mitochondria and cytoplasmic fat globules: the presence of residual bodies and myelin figures indicate an increase in the rate of degradation of organelles. There was no appreciable increase in the number of necrotic cells seen on electron microscopy of cultures exposed to high concentrations of thiopentone or other potent barbiturates, but the presence of debris in the DNA cytogram at 72 h indicated some increase in the death rate of cells exposed to the growth suppressing barbiturates. It would be inadvisable to administer these short- and intermediate-acting barbiturates over long periods, particularly at high dosage, because of the potential danger of iatrogenic immunosuppression.

Adult↗