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Biomedical subjects

S Pierce

Publications and source records attributed to S Pierce.

At least 109 records · Page 6Linked to original sources
PubMed1991

Quality assurance program for a nuclear pharmacy.

The development of a quality assurance program for a nuclear pharmacy service is described. The program was established to complement and test the extensive quality control procedures in the nuclear pharmacy. Based on current nuclear pharmacy standards of practice and government regulations, audits were developed and tested for a 12-month period. Results of these audits were closely analyzed for their relevance and impact on the service. These results showed that the standards for the established quality control program were being met. It was concluded that the quality assurance program was a useful and practical tool.

Forms and Records Control↗
PubMed1990

Afferent and efferent innervation of the cat cochlea: quantitative analysis with light and electron microscopy.

The purpose of the present study was to describe the longitudinal and radial gradients of cochlear innervation in the cat. To this end, afferent and efferent terminals of both the inner (IHC) and outer hair cell (OHC) regions were reconstructed from serial ultrathin sections at six and eight cochlear locations, respectively, corresponding to roughly octave intervals of characteristic frequency (CF). Analysis of the afferent innervation of the IHCs showed 1) the number of radial fibers per IHC rises from 10 per IHC at the 0.25 kHz region to a maximum of 30 per IHC at the 10 kHz locus; 2) branching of radial fibers is essentially restricted to regions apical to the 1.0 kHz point; and 3) there are significant differences in synaptic-body morphology for synapses on different sides of the IHC, corresponding to known differences in afferent threshold and rate of spontaneous activity. With respect to efferent innervation in the IHC area, we found 1) that there were numerous vesicle-filled terminals contacting every IHC examined; however, those with obvious synaptic specialization were confined to the most apical regions; and 2) there were roughly the same numbers of efferent synapses per radial fiber at all cochlear locations; however, at each location, radial fibers contacting the modiolar side of the hair cell (corresponding to high-threshold afferents) showed significantly more efferent synapses than radial fibers contacting the pillar side. Analysis of the OHC afferent innervation showed 1) a clear rise in numbers of terminals per OHC from roughly 3 per cell in the base to 15 per cell in the apex, 2) no systematic differences in the numbers of terminals as a function of OHC row, and 3) that synaptic bodies at the OHC afferent synapse are common only apical to the 1.0 kHz locus. Counts of efferent terminals on OHCs revealed 1) maximal numbers (9 per OHC) between the 6 and 24 kHz regions and 2) striking decrease in terminal counts from first- to third-row OHCs. Ultrastructural data on efferent innervation were compared quantitatively with light-microscopic analysis of cochleas immunostained (with antibody to synaptophysin) to reveal all vesiculated terminals.

Afferent Pathways↗
PubMed1988

N-myc oncogene RNA expression in neuroblastoma.

Tumor specimens from 33 patients with neuroblastoma were assayed for amplification of the N-myc oncogene and RNA expression to determine whether N-myc RNA expression levels correlated with N-myc gene amplification and clinical outcome. N-myc gene amplification was detected in one stage II tumor, one stage IV-S tumor, and seven stage III or IV tumors. In each case, N-myc RNA expression roughly paralleled N-myc gene amplification. However, enhanced N-myc RNA expression was not confined to tumors with N-myc gene amplification: all of the early (stage I and II) tumors, five stage IV-S tumors, and 12 advanced (stage III and IV) tumors had levels of N-myc RNA that were elevated up to 50-fold. While N-myc gene amplification correlated with prognosis, there was no such correlation with levels of N-myc RNA expression. The precise role of the N-myc gene in the pathogenesis of neuroblastoma remains unclear.

Adolescent↗
PubMed1988

A comparison of marrow transplantation with chemotherapy for adults with acute leukemia of poor prognosis in first complete remission.

From July 1980 to November 1985, 109 patients with acute myelogenous and lymphoblastic leukemia who had reached a complete remission (CR) following induction treatment were assigned to a study comparing marrow transplantation with chemotherapy as a postremission treatment. Sixty-nine patients did not have a human leukocyte antigen (HLA)-identical donor, and therefore served as chemotherapy controls; 40 patients had HLA-identical donors, and therefore were assigned to the transplant arm. Of these, 23 were transplanted in first remission and 17 were not. Ten of these 17 were subsequently transplanted in relapse. Initially, only patients with poor prognosis determined by a predictive model were entered into the study. Subsequently, patients with moderately poor prognosis were admitted. Comparing the chemotherapy group with the patients transplanted in first CR, significant control of leukemia relapse in transplanted patients was seen in the subgroup with acute myelogenous leukemia (AML) (P less than .1), and acute lymphoblastic leukemia (ALL) (P less than .01), in the poor (P = .01) and intermediate subgroup (P = .01), and in the good-prognostic groups (P = .05). The survival was affected significantly in only the poor and intermediate subgroups. The use of predictive models might help to select patients for whom bone marrow transplantation is appropriate in first remission and those for whom bone marrow transplantation can be left as the initial treatment of relapse. Predictive models could further be helpful in comparing studies performed at different transplant centers.

Adolescent↗
PubMed1981

Generation of idiotype-specific T cell help through network perturbation.

Different manipulations of BALB/c mice were used to generate idiotype-specific help: neonatally induced suppression of the T 15 idiotype and low-dose priming with anti-T15 antibody. The splenic foci culture system was used to study T15-idiotype-recognizing helper T cells under limiting-cell-dose conditions. These treatments induced T15 idiotype-specific help for B cells responding to TNP-T15. Normal or hemocyanin-primed BALB/c mice did not supply T15 idiotype-specific help. The helper cells were sensitive to anti-Thy-1.2 and complement treatment and can distinguish T15 from an idiotype-different, PC-binding myeloma protein, M167, and the TNP binding myeloma protein, M460. These data show that idiotype-specific T helper cells can be induced by at least two different manipulations of the idiotype network. These manipulations presumably do not act directly on the T15-recognizing T cells, but must involve complementary idiotypic circuits that stimulate anti-T15 specific T cells. Furthermore, this study demonstrates that the splenic-fragment culture technique provides a general method to investigate, at the single cell level, idiotypic T-B cell interactions induced by perturbations of the immune network.

Animals↗
PubMed1981

Normal brain stem auditory evoked potentials recorded in sleep apneics during waking and as a function of arterial oxygen saturation during sleep.

Brain stem auditory evoked potentials (BAEPs) can be utilized as an index of neuronal dysfunction at the level of the brain stem. These waves are known to be independent of level of arousal. In the present study, BAEPs (waves I-V) to monaural click stimulation were recorded during daytime waking and as a function of arterial oxygen saturation during nocturnal sleep in 6 subjects with obstructive sleep apnea syndrome. Normal conduction times were recorded in all 6 subjects during daytime waking. In addition, BAEPs remained stable in every case during sleep-related apneas when averaged over intervals of arterial oxygen saturation as low as 45-70% in one subject. Our data indicate that (1) the repetitive oxygen desaturation experienced during sleep in apneics had neither acute nor chronic, measurable effects on neurons which subserve the BAEP, and (2) a brain stem abnormality involving the structures which subserve the BAEP does not underly obstructive sleep apnea.

Adolescent↗
PubMed1978

Glutathione peroxidase activities from rat liver.

There are two enzymes in rat liver with glutathione peroxidase activity when cumene hydroperoxide is used as substrate. One is the selenium-requiring glutathione peroxidase (glutathione:hydrogen-peroxide oxidoreductase, EC 1.11.1.9) and the other appears to be independent of dietary selenium. Activities of the two enzymes vary greatly among tissues and among animals. The molecular weight of the enzyme with selenium-independent glutathione peroxidase activity was estimated by gel filtration to be 35 000, and the subunit molecular weight was estimated by dodecyl sulfate-polyacrylamide gel electrophoresis to be 17 000. Double reciprocal plots of enzyme activity as a function of substrate concentration produced intersecting lines which are suggestive of a sequential reaction mechanism. The Km for glutathione was 0.20 mM and the Km for cumene hydroperoxide was 0.57 mM. The enzyme was inhibited by N-ethylmaleimide, but not by iodoacetic acid. Inhibition by cyanide was competitive with respect to glutathione and the Ki for cyanide was 0.95 mM. This selenium-independent glutathione peroxidase also catalyzes the conjugation of glutathione to 1-chloro-2,4-dinitrobenzene. Along with other similarities to glutathione S-transferase, this suggests that the selenium-independent glutathione peroxidase and glutathione S-transferase activities in rat liver are of the same enzyme.

Animals↗
PubMed1977

A syntactic investigation of verbal autistic, mentally retarded, and normal children.

The syndrome of childhood autism is typified by major abnormalities in language development, yet there are few systematic descriptions of autistic children's linguistic systems. We have, therefore, begun a comprehensive investigation of the language of verbal autistic children and concentrate in this paper on comparing the syntax used by 10 verbal autistic children matched for nonlinguistic mental age with a group of mentally retarded subjects and normal controls. Two different means of assessing syntactic development were utilized: Lee's Developmental Sentence analysis and Chomsky's Transformational analysis. The autistic group was found to rank significantly lower than either the mentally retarded or the normal groups in terms of Developmental Sentence Scores. When a transformational grammar was used to describe the language samples of our subjects the autistic children were typified by a higher error rate and lower level of complexity compared to the other two groups. However, the results also indicate that the grammatical system of autistic children is rule-governed and probably not unlike that of young normal or retarded children. In conclusion, it appears that the syntactic abnormalities characteristic of autism are attributable to an extreme delay in language development as well as to an impaired ability to make use of linguistic rules.

Autistic Disorder↗
PubMed1977

Effects of selenite and selenomethionine on glutathione peroxidase in the rat.

The activity of glutathione (GSH) peroxidase (EC 1.11.1.9) decreased in tissues of rats fed a diet deficient in selenium. A single dose of 300 mug selenium by stomach tube increased GSH peroxidase activity within 48 hours. The effects of selenite and selenomethionine on GSH peroxidase activity were roughly similar. This study provides evidence that selenium from both selenite and selenomethionine is readily available for synthesis of the selenoenzyme GSH peroxidase in rat tissues.

Animals↗
PubMed1976

Phonological investigation of verbal autistic and mentally retarded subjects.

A review of the pertinent literature indicates that autistic children are likely to show normal but delayed development of speech sounds. In contrast, atypical phonological development is suggested by experiments demonstrating that autistic subjects are deficient in their ability to extract the components of structured auditory input. A systematic investigation of the speech sound systems of verbal autistic and mentally retarded children reveals a delay in phoneme acquisition, as well as a relative uniformity of error types in both groups. The autistic subjects, however, differ significantly from the mentally retarded in the phonemic substitutions which they make. Autistic subjects are also characterized by a high correlation between frequency of phonological errors and level of overall language development. The findings are interpreted as supporting the hypothesis that the autistic group shows a more global delay in language development.

Adolescent↗
PubMed1975

A serum haemagglutinating property dependent upon polycarboxyl groups.

A serum agglutinin reactive with red cells in the presence of polycarboxyl groups is reported. It is likely that this represents an additional example of the type of agglutinin previously described as agglutinating red cells in the absence of ionized calcium. Experimental evidence is presented indicating that it is free polycarboxyl groups that potentiate agglutination and that any metal ion, such as calcium, capable of chelating with these groups will prove to be inhibitory.

ABO Blood-Group System↗
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Cardiovascular Diseases↗