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Biomedical subjects

D Riedel

Publications and source records attributed to D Riedel.

At least 55 records · Page 3Linked to original sources
PubMed1988

The suppressive effects of recombinant human tumor necrosis factor-alpha on normal and malignant myelopoiesis: synergism with interferon-gamma.

The modulation of growth of normal and leukemic myeloid progenitor cells in soft agar cultures by recombinant human tumor necrosis factor-alpha (TNF alpha) and recombinant human interferon-gamma (IFN gamma) was investigated. TNF alpha inhibited colony formation of all colony types representing different maturational stages of normal progenitor cells committed to the myeloid lineage with different orders of sensitivity. Blast-type colonies derived from patients with acute myelogenous leukemia were more sensitive to TNF alpha inhibition than progenitor cells purified from normal bone marrow or bone marrow from patients with stable-phase chronic myelogenous leukemia. The response of most colony types to IFN gamma was poor. However, when IFN gamma was administered together with TNF alpha, synergistically enhanced antiproliferative effects were detected in all colony types tested. The antiproliferative action of IFN gamma on myelopoiesis was enhanced in culture by the presence of autologous monocytes, presumedly by inducing endogenous production of TNF alpha. However, TNF alpha seemed to act directly on the progenitor cells themselves to suppress their clonal growth, rather than involving accessory marrow elements such as monocytes and/or T lymphocytes.

Antibodies, Monoclonal↗
PubMed1987

The effect of DEET (N,N-diethyl-m-toluamide) on dermal persistence and absorption of the insecticide fenitrothion in rats and monkeys.

The in vitro persistence of 14C-ring-labeled fenitrothion in acetone (F-A) or N,N-diethyl-m-toluamide (DEET) (F-D) vehicles was determined, and in vivo studies were conducted to determine the persistence and absorption of [14C]fenitrothion in acetone or DEET applied to the skin of rats and rhesus monkeys. In vitro persistence of [14C]fenitrothion was significantly enhanced in DEET vehicle, and the percent residual 14C activity at 24 h was positively correlated with the amount (micrograms) of DEET employed (e.g., in vitro, 98.6 +/- 1.7% 14C recovery after 24 h with [14C]fenitrothion in DEET versus 1.9 +/- 0.3% without DEET). Significantly greater (p less than 0.05) fenitrothion 14C activity was detected in skin swabs taken after 24 h at the dose site with DEET vehicle from rats [acetone (F-A): 15.0 +/- 5.8%; DEET (F-D): 31.5 +/- 3.9%)] and monkeys (F-A: 3.2 +/- 1.5%; F-D: 9.7 +/- 6.0%). A lag in the urinary excretion kinetics was observed for F-D in comparison with F-A for both rats and monkeys. The total percent urinary 14C recovery was significantly higher in rats dosed with F-A (73.0 +/- 7.4%) than with F-D (52.4 +/- 8.8%) but not in monkeys (F-A: 34.7 +/- 7.1%; F-D: 36.7 +/- 2.9%). The observed species-related differences are discussed in context with the use of animal models for predicting dermal penetration of pesticides in humans.

Animals↗
PubMed1986

Dermal exposure and urinary metabolite excretion in farmers repeatedly exposed to 2,4-D amine.

Following multiple exposures to 2,4-D amine salts under normal field conditions in which ground rigs were used, farmers who sprayed once or twice had an average dermal exposure of 655 micrograms 2,4-D acid equivalents (a.e.)/kg a.e. sprayed and an average cumulative urinary metabolite excretion of 10.9 micrograms 2,4-D a.e./kg a.e. sprayed. One very high outlier value was excluded from these averages (F). Following 4 to 7 exposures, the average cumulative dermal exposure was 1,077 micrograms 2,4-D a.e./kg a.e. sprayed and the average cumulative urinary metabolite excretion was 21.5 micrograms 2,4-D a.e./kg a.e. sprayed. The amount of 2,4-D metabolite in urine was significantly correlated with the amount of herbicide sprayed and the time required for the urinary metabolite excretion to return to background concentration was related to the amount sprayed and the number of exposures.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1984

Endoscopic sphincterotomy: follow-up evaluation of effects on the sphincter of Oddi.

Endoscopic sphincterotomy (ES) alters the structure and motor function of the sphincter of Oddi (SO). The magnitude and duration of these changes, however, have not been critically examined. Before ES, 22 patients with common bile duct stones were evaluated by endoscopic retrograde cholangiography. The pressure gradient between the common bile duct and the duodenum, the SO basal pressure, and the SO peak phasic pressures were obtained. After ES, the electrosurgical incision length was determined using the extended papillotome and an inflated Fogarty balloon as reference. A high correlation existed between the endoscopist's estimate of ES incision size using this technique and the actual length of simulated incisions fashioned in cardboard mounts. These studies were repeated in all 22 patients at 1-yr follow-up and in 8 of these patients at 2-yr follow-up. At 12 mo and 24 mo after ES, the common bile duct (CBD) to duodenal pressure gradient and the sphincter of Oddi basal pressure were virtually eliminated. The amplitude of SO phasic contractions was significantly diminished 12 mo after ES (124 +/- 16 mmHg to 37 +/- 10 mmHg; p less than 0.001), but 24 mo after ES, SO phasic contraction amplitude was not significantly different from the values before ES. Incision length at 1-yr follow-up was reduced in the group of 22 patients from 11.6 +/- 0.8 mm to 8.3 +/- 0.5 mm (p less than 0.001), and in the group of 8 patients from 11.0 +/- 1.5 mm to 7.5 +/- 0.7 mm (p less than 0.025). After an additional 12 mo, however, i.e., 24 mo after ES, the incision length was 6.5 +/- 0.7 mm. There was no significant difference in incision length between the 12-mo and 24-mo examinations. We conclude that after ES, incision length decreases during the first year. There appears to be no further significant reduction in incision length at 2 yr. In addition, the reduction of the CBD to duodenal pressure gradient and the SO basal pressure remain unchanged for at least 2 yr. These manometric findings support the observation that after ES the enlarged opening of the CBD into the duodenum remains open for at least 2 yr.

Ampulla of Vater↗
PubMed1975

Reproduction, structure and host specificity of Trypanosoma (Herpetosoms) tamiasi sp. n. from the eastern chipmunk, Tamias striatus.

Trypanosoma (Herpetosoma) tamiasi sp. n. is described from blood and organs of the eastern chipmunk, Tamias striatus, and the least chipmunk, Eutamias minimus. In experimentally infected Tamias striatus and E. minimus, Trypanosoma tamiasi reproduced by equal binary fission in the trypo-, sphaero-, epi-, or amastigote form, mainly in lymphoid organs. Trypomastigotes developed from amastigotes through epimastigotes, or from sphaeromastigotes, mainly in the same organs. The mean lengths of body and flagellum of trypomastigotes increased linearly until the organisms reached a maximum length of similar to 37-39 mum. The distance between the nucleus and kinetoplast increased to a mean total length of similar to 33 mum, and thereafter remained constant. Parasitemias of up to 2.5 times 10-7 trypanosomes/ml were produced in Tamias striatus by inoculation with bloodstream, culture, or flea gut forms of Trypanosoma tamiasi; natural parasitemias in Tamias striatus peaked at up to 2.1 times 10-7 trypanosomes/ml. One E. minimus and 2 Spermophilus tridecemlineatus developed parasitemias of more than 1 times 10-6 trypanosomes/ml after inoculation of bloodstream forms of Trypanosoma tamiasi; other experimentally inoculated rodents, including mice, rats, and Spermophilus richardsonii, proved refractory. In chipmunk fleas, Megabothris acerbus, Megabothris quirini, and Tamiophila grandis, bloodstream forms of Trypanosoma tamiasi developed to metacyclic forms in 4-9 days; in rat fleas, Xenopsylla cheopis and Nosopsyllus fasciatus, they survived with little development for up to 2 days, and in kissing bugs, Rhodnius prolixus, up to 10 days. Apparently, the speciation of this trypanosome involved adaptation to certain species of both fleas and rodents.

Animals↗
PubMedDate not supplied

Nursing management of patients with brain injury requiring one-on-one care.

Patients with traumatic brain injury currently constitute a major portion of the rehabilitation population. Although agitated, restless, and wandering behavior is an expected stage in the recovery process of these patients, issues involving the patient's and the staff's safety can arise when these behaviors are excessive and hard to control. In addition, patients may have difficulty achieving their rehabilitation goals because of these behaviors. One-on-one supervision, specialized interventions, and a structured approach often are necessary and beneficial if patients are to achieve rehabilitation goals. The facility described in this article has a large population of patients with head injury who require one-on-one supervision. Guidelines for the nursing management of two different patient populations that required two different interdisciplinary approaches were developed and established.

Brain Injuries↗
PubMedDate not supplied

Fish consumption by Vietnamese women immigrants: a comparison of methods.

In this study, the measurement properties of an interview-administered fish consumption frequency questionnaire, used with a pilot study of 20 Vietnamese immigrant women, were described. Reproducibility across two summer interviews and one winter interview for estimates of seasonal and yearly intake of Great Lakes fish was moderate (intraclass correlation coefficients: .51-.61). Detailed questioning, by species, resulted in higher estimates of mean overall consumption (44.6-57.8 meals/y) than did asking about any fresh-water fish consumed (33.5-46.1; differences 5.1-15.7). Estimates based on the fish consumption frequency questionnaire (i.e., 6.2+/-2.0 meals per winter season) were comparable with those based on extrapolation from a 1-mo calendar (5.8+/-5.6); however, both estimates of consumption were far less than a weighed record (29.1+/-22.2). The results of this study suggest that measurement variation in fish consumption estimates should be detailed in research reports and should be discussed with respect to risk assessments.

Adult↗