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Biomedical subjects

A Kaul

Publications and source records attributed to A Kaul.

At least 145 records · Page 8Linked to original sources
PubMed1981

Cell-mediated immunity to cytomegalovirus in pregnant women.

Employing the techniques of in vitro lymphocyte transformation (LTF) and complement fixation, cell-mediated immunity (CMI) and antibody to cytomegalovirus (CMV) were studied in pregnant and nonpregnant women. The LTF activity was determined by the whole blood microassay using four strains of CMV (AD-169 and its early antigen [EA], Davis, Veca, and Towne strains), and phytohemagglutinin (PHA). Lymphocyte transformation response to specific CMV antigens at 11-30 weeks of gestation and to nonspecific mitogen (PHA) in all pregnant and postpartum women were found to be significantly depressed compared with the nonpregnant women. The lower LTF responses to CMV antigen and PHA were found in specimens taken from pregnant women at 21-30 weeks of gestation. There were no significant differences in the mean complement-fixing (CF) antibody titers and the percentage of E-rosette-forming T lymphocytes between subjects in various stages of pregnancy. In addition, concanavalin A (Con A)-generated suppressor T cell activity was evaluated in pregnant and nonpregnant women. The suppressor effect of Con A-activated lymphocytes in the pregnant women was somewhat higher than in nonpregnant women. These observations suggest that CMV-specific suppression of cellular immunity may play an important role in reactivation of CMV in pregnancy.

Adolescent↗
PubMed1981

[Responsibility, status and role of the medical physicist in the Federal Republic of Germany (author's transl)].

Pursuant to the regulations of the Roentgenverordnung (decree about X-ray examination and therapy), the Strahlenschutzverordnung (decree about radiological protection), and the Richtlinie Strahlenschutz in der Medizin (guide-line for radiological protection in medical practice), the responsible collaboration of a physicist on the diagnostic and therapeutic application of ionizing radiation is prescribed by law or, at least, seems reasonable with regard to the protection of the patient. This is why the authors describe the tasks and necessary qualifications of the physicist (competence as to radiological protection and professional admission) which are prescribed by law in the Federal Republic of Germany or which are desirable with respect to the performance of radioprotective measures during the application of ionizing radiation in medical practice. Furthermore, the authors summarize the results of a recently made inquiry about the state (e.g. education, professional experience, participation in medical care) and the role of the medical physicist (e.g. institutionalization of Medical Physics, educational work).

Germany, West↗
PubMed1980

Radioiodine: biokinetics, mean dose and dose distribution.

For the radioiodine isotopes I-123, I-125, I-131, and I-132 the mean tissue dose and local dose distribution in the epithelial cells of a follicle have been calculated and compared to each other. Moreover, dose factors have been estimated for I-131 as a function of age considering age-dependent ingestion (milk consumption) and inhalation rates. Thereby, besides age-dependent biological half-times and thyroid masses, the thyroidal iodine uptake was assumed to be independent from age and taken to be about 1.7 the normal for an insufficient dietary iodine intake as in the Federal Republic of Germany.

Adolescent↗
PubMed1980

[Elimination of lead from rats under biological stress, and application of Na2Ca-EDTA (author's transl)].

It is currently thought that lead is released from organic depots in response to internal or external stress to the organism. Using young Wistar rats, we were unable to confirm this view. Chronic lead levels, persisting over a period of 20 days, were achieved by the intraperitoneal injection of labelled (210Pb) lead acetate into rats (5 mg/kg body weight). The animals were divided into four groups. One group was maintained normally as a control, while two others were subjected to stress, i.e. starvation and injection of an autolysate of bacteria, respectively. All three of these groups showed identical behaviour with respect to total body radioactivity, femur radioactivity (representing the chief skeletal depot), and excretion of radioactivity. The fourth group received Na2Ca-EDTA (sodium salt of the calcium chelate of ethylenediaminetetraacetic acid). The decrease of total body radioactivity and femur radioactivity, and the relative excretion of 210Pb had almost levelled out by about 14 days, and was related mainly to the elimination of lead from the bones (in parenchymatous organs, the cell membrane forms a barrier to the therapeutic removal of intracellular lead). This illustrates the effectiveness of early treatment in lead poisoning, and the ineffectiveness of continuous therapy.

Animals↗
PubMed1980

[Absorbed dose for children and juveniles in nuclear medical diagnostics (author's transl)].

By means of special models and methods of calculation, values of the specific absorbed dose for the ICRP-reference man were corrected for the application to children and juveniles. For several commonly used radio-pharmaceuticals organ-dose values were calculated. For reasons of comparing the age dependence, values of the effective whole-body dose equivalent were computed. The age-dependence of these values mainly reflects the mass-dependence of the absorbed dose, so that for the administration of an age-dependence amount of radio-pharmaceutical the absorbed whole-body dose is nearly independent of the age, while the organ-dose may vary to a much greater extent.

Absorption↗
PubMed1979

Cell-mediated immunity to cytomegalovirus in patients receiving immunosuppressive therapy.

Employing the techniques of complement-fixation (CF), immunofluorescence (IF), and in vitro lymphocyte transformation (LTF), the humoral antibody response and cell-mediated immune (CMI) response to cytomegalovirus (CMV) were studied in the serum and peripheral blood lymphocytes in 19 normal children (controls) and 23 patients with renal disease who were receiving immunosuppressive therapy or undergoing hemodialysis. The LTF activity was determined by the whole blood microassay using two strains of CMV (AD-169 and Davis) and phytohemagglutinin (PHA). The antibody level responses to CMV in different groups of subjects were generally similar. The LTF response to PHA as evidenced by delta cpm activity was moderately depressed in immunosuppressed and hemodialyzed subjects compared to the response observed in the controls. The mean delta cpm activities in response to AD-169 and Davis strains of CMV in seropositive immunosuppressed patients were about one-fifth and one-third lower respectively than those of seropositive normal controls. These observations suggest that an impairment of CMV specific cellular immunity may be an important mechanism underlying the increased susceptibility to CMV infections in patients with chronic renal disease who receive immunosuppressive therapy.

Adolescent↗
PubMed1979

Effect of methyl thiouracil on radioiodine thyroidal retention in rats.

Some goitrogens like methyl thiouracil (MTU) because of their thynamide grouping act as antithyroid drugs inhibiting the organification of iodide, but do not alter the iodide transport. Their administration to an intact animal, therefore, might alter the thyroidal iodine kinetics. Here an attempt has been made to study the effect of MTU on thyroidal iodine kinetics in rats as well as to find out whether any difference in kinetics could be detected between different radioiodines, viz., 131I, 125I, and 123I. Cumulated thyroidal activity which is a time integral of the activity has been taken as the parameter to represent the sum effect of thyroidal iodine kinetics over a specific time period of interest. From the in vivo thyroidal activity measurements, carried out over extended periods of time, the cumulated activity was calculated for both MTU treated and normal rats that received 131I, 125I, or 123I at different times before the MTU start. Within a day of the start of the MTU there is a rapid loss of thyroidal iodine. The severity of the loss depended upon the time that elapsed between the start of the MTU schedule and the particular radioiodine administered. The absence of isotopic effect on the uptake as well as on the rate of uptake for the three different radioiodine isotopes studied has been brought out.

Administration, Oral↗
PubMed1979

Cell-mediated immune response to respiratory syncytial virus infection: relationship to the development of reactive airway disease.

The possibility that cell-mediated immunity might play a role in the pathogenesis of infection with respiratory syncytial virus was evaluated in a study of 39 infants. Infection with RSV was confirmed by identification of virus in nasopharyngeal secretions using immunofluorescence, and by tissue culture infectivity. CMI, as determined by a whole blood lymphocyte transformation technique, was evaluated in samples taken 0 to 10 and 20 to 60 days after the onset of illness. Patients diagnosed as having RSV-induced bronchiolitis or recurrence of asthma had evidence of significantly (P less than 0.01) higher degree of CMI in the 0 to 10-day period than patients with RSV pneumonia or upper respiratory illness. Higher CMI activity in the 20 to 60-day period was also seen in patients with more severe illness, with moderate-to-severe degree of hypoxia. A positive correlation was observed between the degree of LTF activity in samples taken 20 to 60 days after the onset of illness ard subsequent episodes of wheezing. Eleven patients had one or more episodes of wheezing in the first six months after RSV infection. LTF activity in samples taken during the 20 to 60-day period from these patients was significantly higher (P less than 0.02) than LTF activity in corresponding samples from six patients who were free of wheezing in the six months after RSV infection. The results suggest that alterations of RSV-specific cell-mediated immune mechanisms may result in an increased tendency toward airway reactivity on primary and subsequent exposure to RSV and possibly to other agents.

Bronchial Spasm↗
PubMed1979

Cell-mediated immunity to cytomegalovirus in immunocompromised patients: effect of radiation or chemotherapy.

Using the techniques of complement fixation, immunofluorescence, and in vitro lymphocyte transformation (LTF), we studied the humoral antibody and cell-mediated immunity to cytomegalovirus (CMV) in normal subjects, in patients with cancer receiving localized or nonlocalized radiation, and in renal transplant recipients on immunosuppressive chemotherapy. The LTF activity was determined by the whole blood microassay, using four strains of CMV (AD-169, Davis, Veca, and Towne), AD-169 early antigen, and phytohemagglutinin (PAH). The renal transplant subjects manifested significantly depressed LTF responses to PHA and CMV and frequent presence of immunoglobulin M and early antigen-specific antibody response. The depressed LTF response to CMV recovered significantly 2 years after transplantation. The cancer patients were also characterized by a profound drop in LTF responses to PHA and CMV and in immunoglobulin M and early antigen-specific antibody response after nonlocalized radiation. LTF responses to AD-169 and Towne strains were found to be higher than those to Davis and Veca strains. The LTF response to PHA declined with age. However, LTF responses to specific CMV antigens were found to be somewhat increased with advancing age. These observations suggest that transplantation-associated suppression of CMV-specific cell-mediated immunity may improve a few years after transplantation despite continued immunosuppressive therapy.

Adolescent↗
PubMed1978

Microscopic dose distributions due to iodine isotopes in thyroid.

Microscopic electron dose distributions inside and outside the colloid spheres of thyroid tissue of radii 15-150 micron containing 1.5 muCi/g 123I, 125I, 131I, and 132I uniformly distributed have been calculated by the application of Berger's scaled absorbed dose functions approximately standard polynomial regression techniques. For 131I, 123I and 132I whose electron or effective beta energy ranges are at least few times more than the sphere sizes considered the contributions of energy emitted from neighbouring follicles have been included into the dose calculations. Additionally, the frequency mean and energy mean of microscopic event-size distributions in small spherical 125I sources have been computed in rad per one 125I disintegration.

Electrons↗
PubMed1978

Thorotrast kinetics and radiation dose: results from studies in thorotrast patients and from animal experiments.

As a presupposition for estimating the mean tissue dose from intravascularly injected Thorotrast results of investigations on tissue distribution and steady state activity ratios of 232Th and daughters in Thorotrast patients were compiled and are presented as "best estimates". Special emphasis has been given to the non-uniformity of Thorotrast distribution on the organ and cellular level on the basis of results from animal experiments. Moreover, the variation widths of the mean tissue doses were calculated from the individual standard errors of the mean Thorotrast tissue distribution and activity ratios. According to the results of Thorotrast tissue distribution analyses about 97% of intravascularly injected colloidal ThO2 are retained by the organs of the reticulo-endothelial-system (RES) of the average Thorotrast patient (liver: 59%; spleen: 29%; bone marrow: 9%). Only 0.7 and 0.1% are distributed within the lungs and the kidneys, respectively. The fractional retention of 232Th in the marrow-free skeleton proved to be 2% on the average. Considering in addition the results on the steady state activity ratios between 232Th and its daughters and self-absorption of alpha-energy in Thorotrast agglomerates the mean annual tissue doses to the liver, spleen, red bone marrow, lungs (respiratory zone), and cells on bone surface, e.g., from 30 ml intravascularly injected Thorotrast are about 30 (10-70), 80 (30-200), 10 (4-27), 4.5 (1.8-11.3), and 15 (6-38) rad. The variation widths of the mean tissue doses given in brackets are based upon an average individual standard error of the mean Thorotrast tissue distribution and activity ratios of 150%. The data on mean tissue doses, however, do not include variations of the dose due to macroscopic inhomogeneities of Thorotrast distribution on the organ level, which in the liver may go up to a factor of 50. Contrary to the mean tissue dose the local annual dose, i.e., the dose to cells adjacent to the surface of 0.1-50 micron Thorotrast aggregates is between 40 and 40,000 rad.

Alpha Particles↗
PubMed1978

Respiratory syncytial virus infection. Rapid diagnosis in children by use of indirect immunofluorescence.

Specimens of 387 nasopharyngeal suction smears obtained from 354 children hospitalized with acute respiratory infections during an eight-month period were examined for the presence of respiratory syncytial (RS) virus by the indirect immunofluorescence antibody technique (IFAT) and by conventional tissue culture infectivity techniques. Respiratory syncytial virus was identified in nasopharyngeal suction smear specimens from 123 of these specimens (32%) with the use of both techniques. Of the specimens positive on tissue culture 92% were also positive for RS virus by IFAT. However, eight specimens positive for RS virus by tissue culture were negative by IFAT, although three of the specimens were technically unsuitable. Six percent of the specimens negative for RS virus by tissue culture were positive for RS virus antigen when tested by IFAT. Using IFAT, identification of RS virus could be accomplished within four to six hours, whereas isolation by tissue culture took an average period of ten days. These data suggest that IFAT is a reliable means for the rapid diagnosis of RS virus infection in infants and children.

Adolescent↗
PubMed1978

Development of in vitro correlates of cell-mediated immunity to respiratory syncytial virus infection in humans.

Groups of infants and children with infections due to respiratory syncytial virus (RSV) were tested at the onset of illness and one, two, and five months later for the presence of RSV-specific cell-mediated immunity, as determined by in vitro lymphocyte transformation (LTF) activity, and for complement-fixing (CF) antibody. An LTF response specific for RSV was observed in 65 % of patients, and the response was largely associated with E-rosette-forming thymus-derived (T) lymphocytes. A significant cell-mediated immune response was observed in 78% of patients six months of age or younger, whereas only 46% of patients older than six months exhibited such responses. The difference between the mean stimulation index of the maximal LTF response in the two age groups was statistically significant (P less than 0.05). On the other hand, a fourfold or greater rise in titers of CF antibody was observed in only 22% of patients six months of age or younger, whereas significant rises in antibody activity were observed in 50% of subjects older than six months. In view of the fact that RSV infection is most severe in the young infant, these observations raise the possibility that cell-mediated hypersensitivity reactions may be related to the pathogenesis of RSV infection of infants.

Antibody Formation↗