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Biomedical subjects

C L Schultz

Publications and source records attributed to C L Schultz.

At least 37 records · Page 2Linked to original sources
PubMed1996

A longitudinal study of the grief of mothers and fathers of children with intellectual disability.

As a follow-up to a single-point-in-time study which suggested support for the proposition that grieving is an ongoing feature of parenting children with intellectual disability, the present investigation reports findings based on annual interviews conducted over a three-year period. Longitudinal outcomes on measures used to define grief largely confirmed the original findings. Of particular interest were (a) indications of the presence of grief over time (b) the finding that the 49 mothers and 49 fathers report similar intensity of continued wishing for what might have been, and (c) the conclusion that the responses of the mothers on the Impact of Event Scale and to current levels of distress when thinking about time of diagnoses are significantly more intense than those of the fathers. Attention is drawn to patterns emerging from gender-related differences. Resulted are discussed within the framework of four mandates for research and practice, with particular reference to psycho-educational support through groupwork.

Adolescent↗
PubMed1995

Bacterial adhesion measurements on soft contact lenses using a Modified Vortex Device and a Modified Robbins Device.

S. marcescens 8100 and P. aeruginosa 15442 were used to study bacterial adhesion to hydrogel contact lenses which had not been worn. Bacterial removal from unworn lens materials was assessed with a calibrated vortex device modified with a digital rpm readout and fitted with a test tube attachment (MVD). The MVD, which relies on a whirlpool-like force to remove the bacteria, showed that bacteria adhered to the same degree to etafilcon A, vifilcon A and polymacon lenses under standardized conditions. Tracking the isoenzyme patterns of these bacterial species over time showed instability of S. marcescens upon repeated passage. This instability was not evident with P. aeruginosa. Bacterial adhesion of P. aeruginosa 15442, to human worn and unworn etafilcon A materials was determined with a Modified Robbins Device. The MRD was closed off at both ends stopping medium and bacterial movement after 1 h of fluid flow over the lens surface. The results show that immediately following this 1-h period more bacteria adhere to unworn contact lenses than to worn lenses. However, bacterial counts were equivalent on worn and unworn lenses following 5 h of static incubation.

Bacterial Adhesion↗
PubMed1994

Grieving related to development: a preliminary comparison of three age cohorts of parents of children with intellectual disability.

It is argued that a child with intellectual disability represents an ongoing source of loss and grief for parents. A developmental framework was employed to compare three age cohorts of parents. Grief was operationalized within the affective, behavioural and cognitive domains. Measures of intrusive thoughts, avoidance behaviours, current emotional distress over reminders of time of diagnosis of disability, and intensity of wishing for what might have been were used, collectively, to reflect the parents' grief reactions. As hypothesized, the results indicate no significant age-related differences in the responses of 58 parent dyads but significant gender-related differences. Mothers scored higher than fathers on all measures. However, on the Wishing Scale, there were no significant differences between fathers and mothers. It is concluded that grieving, as defined, is an ongoing feature of rearing a child with intellectual disability and is more intense for mothers than fathers. Results are discussed within the implications for research and practice, with particular reference to the merit of programmes and services which empower parents and strengthen bonds of partnership between parents and professionals.

Adolescent↗
PubMed1992

T helper cell membranes promote IL-4-independent expression of germ-line C gamma 1 transcripts in B cells.

Studies using plasma membranes from activated Th cell clones (Th membranes) to stimulate B cells have shown that both a contact-mediated activation signal plus Th-derived cytokines are required for antibody production. In order to clearly separate and define the role of these two signals in isotype switching, B cells were stimulated with Th membranes in the presence or absence of cytokines, and the transcriptional activity of the unrearranged H chain loci was determined. In the presence of Th membranes, two known switch factors were shown to specifically induce germ-line transcription of the same H chain loci as in LPS-stimulated B cells (IL-4 induced C gamma 1 and C epsilon transcription, transforming growth factor-beta induced C alpha transcription). The contact-mediated activation signal provided by the Th membranes, in the absence of any added cytokines, resulted in the specific induction of C gamma 1 germ-line transcription, and thus functioned as a switch signal for IgG1. These findings provide a mechanism for previously observed IL-4-independent isotype switching to IgG1.

Animals↗
PubMed1992

A comparison of 16 systems to diagnose schizophrenia.

Sixteen diagnostic classification systems were compared to determine the degree of agreement on the diagnosis of schizophrenia. Data were collected by a structured interview method with 284 patients, 52 first admissions, and 196 readmissions. The kappa coefficient was used to calculate interrater reliability and concordance of the systems. Adequate reliability was found for 12 of the systems. However, concordance was generally low; 11 of 120 combinations reached kappa of .40 or higher for the total sample, 16 of 120 for first admissions, and only 6 of 120 for readmissions. These results indicate the restriction of generalization and raise questions as to the empirical validity of the construct of schizophrenia.

Adolescent↗
PubMed1991

Control of isotype switching by T cells and cytokines.

Since the discovery that isotype switching is mediated by a somatic rearrangement event, progress in the field of isotype switching has come a long way: switch factor activity for several T-cell-derived cytokines has been discovered. The mechanism of action of these switch factors seems to be related to their ability to increase or decrease the transcriptional activation of particular switch regions. We have, however, yet to fully understand this important step in isotype regulation.

Animals↗
PubMed1991

Nuclear protein binding to octamer motifs in the immunoglobulin gamma 1 switch region.

Initiation of the immunoglobulin heavy chain switch DNA rearrangement event is thought to involve conversion of the target switch region DNA to an accessible state. Accessibility is likely to be mediated by the binding of regulatory proteins to sequences in or near switch regions. A DNase hypersensitivity assay was used to recognize possible regions of protein binding in the gamma 1 switch region of the B cell hybridoma 470.25. A strong DNase hypersensitive site was identified 5' of the tandemly repeated S gamma 1 sequences. Data from other laboratories suggest that this hypersensitive site is associated with switch recombination to gamma 1. However, the 470.25 cell does hypersensitive sites within the repetitive portion of the gamma 1 switch region was also identified. A gel retardation assay for protein--DNA interaction revealed a sequence present in several copies in the gamma 1 switch region that specifically binds nuclear proteins. This binding sequence, SG1BS, contains the octanucleotide sequence ATGCAAAA, a 7/8 match to the transcriptional enhancer octamer motif found in immunoglobulin promoters and the heavy chain enhancer. Binding competition studies of SG1BS demonstrate that both the octamer and flanking sequences are critical for binding. By size- and tissue-distribution, the factors that bind SG1BS are not distinguishable from the previously identified octamer-binding factors OTF-1 and OTF-2. The ability of proteins to bind the S gamma 1 octamer motif is increased 2.3-fold upon IL-4 induction of lipopolysaccharide-stimulated B cells.

Animals↗
PubMed1991

Small-animal model to measure efficacy and immunogenicity of Shigella vaccine strains.

The development of a small-animal model to test the protective efficacy and immunogenicity of a vaccine strain against shigellosis would greatly facilitate the evaluation of potential vaccine candidates. In guinea pigs, the ability of shigellae to invade and multiply within the corneal epithelium, causing keratoconjunctivitis, closely mimics the invasion process in the intestinal epithelium (B. Sereny, Acta Microbiol. Acad. Sci. Hung. 4:367-376, 1957). The serum response of animals recovering from a Shigella keratoconjunctival infection was determined and found to be consistent with that shown by convalescent humans and primates. This model was used to test the efficacy of two vaccine candidates, and the immune response of the guinea pigs to the vaccine strains was examined. Both vaccine strains demonstrated significant protection against challenge by homologous virulent Shigella strains, and the results were comparable with results obtained in trials with monkeys. The guinea pig model also provides a rapid and inexpensive means of evaluating different immunization regimens as well as of testing other variables such as length of protection against disease.

Animals↗
PubMed1991

Molecular analysis of variant plasmid forms of a bivalent Salmonella typhi-Shigella sonnei vaccine strain.

The Salmonella typhi-Shigella sonnei hybrid vaccine strain 5076-IC was constructed to express the S. sonnei form I antigen, which may play an important role in producing protective immunity. Three clonal variants which existed in preparations of the vaccine could be distinguished phenotypically by lactose utilization, S. sonnei form I antigen expression, and restriction enzyme analysis of large plasmid DNA. Since expression of the form I antigen was lost in two of the clonal variants, genetic instability of the 120-MDa vaccine plasmid appeared to be a potential problem. To examine the molecular basis of this genetic instability, we hybridized large plasmid DNA isolated from the clonal variants to a variety of DNA probes encoding virulence-associated antigens and to Escherichia coli lacZ DNA. Results indicated that DNA rearrangement accompanied by deletions of plasmid material occurred in the vaccine plasmid. In addition, the vaccine plasmid did not contain some S. sonnei genetic material encoding antigenic polypeptides necessary for virulence.

Antigens, Bacterial↗
PubMed1990

Cell wall structures which may be important for successful immunization with Salmonella-Shigella hybrid vaccines.

Three separate lots of S. typhi/S. sonnei hybrid (Ty/Shig) live oral vaccine strain 5076-1C were tested for efficacy in human volunteers challenged with virulent S. sonnei. Two lots (2 and 5) protected volunteers, a third lot (8) did not. The three lots were evaluated by immunological tests and electron microscopy. Lots 2 and 5, which protected, contained bacteria that reacted with anti-flagellar serum and had observable attached flagella and pili. Lot 8, which failed to protect, did not react with anti-flagellar serum, and had no observable pili. There was no correlation between vaccine efficacy and the reaction of IgG in patient's sera in western blot analysis. Surface structures on the Ty-Shig hybrid may be important for generating a protective immune response.

Animals↗
PubMed1989

Anaphylactoid reactions mediated by autoantibodies to cholesterol in miniature pigs.

Antoantibodies to cholesterol were detected and purified from normal (nonimmunized) pig serum. The antibodies were assayed by ELISA with crystalline cholesterol as an Ag and by C-dependent damage to cholesterol-laden liposomes. Intravenous injection of liposomes containing cholesterol into anesthetized animals caused decreased hemolytic complement titers, and induced a reaction consisting of transient neutropenia, thrombocytopenia, respiratory distress, cyanosis, pulmonary and systemic hypertension, and decreased cardiac output. Plasma levels of thromboxane B2 and 6-keto-prostaglandin F1 alpha increased 1300 and 200%, respectively, and leukocyte and platelet counts decreased by 36 and 38%, respectively. Injection of cholesterol-free liposomes did not induce the reaction. These results show that naturally occurring autoantibodies to cholesterol can initiate C activation and can be associated with anaphylactoid reaction to exogenously administered cholesterol in pigs.

Anaphylaxis↗
PubMed1989

Exercise reverses depressed metabolic rate produced by severe caloric restriction.

The effects of caloric restriction and exercise on resting metabolic rate (RMR) were studied in five obese humans. Subjects consumed a 500 kcal.d-1 diet for 4 wk, with the subjects remaining sedentary during the first 2 wk and then exercising 30 min daily at 60% VO2max during the last 2 wk of caloric restriction. After 2 wk of dieting, RMR decreased to approximately 87% of the pre-dieting control value. Over the last 2 wk of dieting with the addition of daily exercise, the fall in RMR was reversed as it returned to the pre-dieting level. In summary, daily exercise reversed the drop in RMR associated with severe caloric restriction.

Adult↗
PubMed1988

[Fine needle biopsy of the pancreas with computerized tomography control].

The results of 96 computed tomography guided percutaneous pancreatic aspiration biopsies were reviewed and compared with the findings at laparotomy or autopsy or with a follow-up of at least one year. In only four instances the follow-up was inadequate and in 29 cases the specimen did not allow a cytologic or histologic diagnosis. Of the remaining 67 biopsies 65 were diagnosed correctly and only 2 incorrectly. This corresponds to a sensitivity of 67.7% and a specificity of 97%. In patients with primary pancreatic cancer the figures for sensitivity or specificity are 76.8% and 97.3% respectively. We did not observe any serious complications. Only one patient had a transient rise of the serum amylase. We believe that the percutaneous aspiration biopsy of the pancreas guided by computed tomography is a safe and effective method in the histologic and cytologic diagnosis of pancreatic lesions.

Biopsy, Needle↗