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Biomedical subjects

C Richards

Publications and source records attributed to C Richards.

At least 19 recordsLinked to original sources
PubMed1995

Monoclonal equine IgM and IgG immunoglobulins.

In order to define equine immunoglobulins (Igs) and to produce monoclonal reference Igs we fused equine peripheral blood mononuclear cells with X63-Ag8.653 non Ig producing murine myeloma cells. A total of 29 equine Ig producing equi-murine heterohybridomas were obtained, of which ten expressed equine Ig for more than 3 months. One of these heterohybridoma lines produced monoclonal IgM, an equine isotype which has not been available in monoclonal form before. Four lines secreted equine IgG of two distinct Ig heavy chain types as assessed by the molecular weight (MW), while the remaining five lines expressed only equine Ig light chains. A sixth Ig light chain expressing variant was obtained by cloning of one of the IgG producing heterohybridoma lines. These monoclonal IgGs were compared with previously described equine IgG monoclonal antibodies (mabs) by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). According to their MW we identified five groups of gamma-chains and four groups of Ig light chains.

Animals↗
PubMed1995

Assessment of in-line filters to prolong the life of intravenous cannulae in cystic fibrosis patients.

Twelve patients with cystic fibrosis received 12 courses of intravenous antibiotics, each over 10-14 days, both with and without the use of an extended-life disposable filter. The design of the trial was to replace the Venflon cannulae as they became non-patent and inserting a filter on alternate occasions. Thus each patient acted as her/his own control. Comparison of times during which cannulae remained patent showed a 50% improvement with use of a filter for 4 patients and no change for 7 patients. There was no significant difference associated with the use of a filter for the group as a whole but our small sample size excludes modest improvements.

Adolescent↗
PubMed1995

Cognitive function, thyroid status and postpartum depression.

Impairment of cognitive function can occur with thyroid disorder and also with depression. Since depression occurs in conjunction with postpartum autoimmune thyroiditis, the question arises as to whether any impairment of cognitive function in postpartum women is related to change in thyroid status or to depressed mood. A total of 242 women (110 thyroid antibody-positive and 132 antibody-negative) were assessed at 8, 12, 20 and 28 weeks postpartum in the outpatients of a district general hospital. Thyroid antibody levels (antimicrosomal and antithyroglobulin) were monitored at monthly intervals, together with plasma T3, T4 and thyroid-stimulating hormone. The main outcome measures were Research Diagnostic Criteria for depression, the 17-item Hamilton Depression Rating Scale and the Edinburgh Postnatal Depression Scale, together with reaction time and digit span. Subjects with postnatal depression showed detectable cognitive impairment independent of thyroid antibody status and actual thyroid dysfunction.

Antibodies↗
PubMed1995

Schistosoma mansoni: changes in the albumen gland of Biomphalaria glabrata snails selected for nonsusceptibility to the parasite.

The LAC-line strain of the snail Biomphalaria glabrata has very low susceptibility to the parasite Schistosoma mansoni and a very low reproductive potential. Upon examination of the reproductive tract of these snails, light and electron microscopy revealed obvious abnormalities in the albumen gland. Secretory cells that are normally cuboidal in susceptible NMRI (F0) snails were squamous in LAC-line snails. These LAC-line cells contained small secretory granules and negligible rough endoplasmic reticulum and Golgi, compared to large granules and an extensive array of both organelles in F0 albumen gland cells. Comparative analyses of soluble protein extracts of F0 and LAC-line albumen glands showed several qualitative differences. Among the most prominent was an 18-kDa protein in F0 snails that was remarkably reduced in the soluble protein extracts of LAC-line snails. Also, metabolic incorporation of [35S]-methionine was impaired in LAC-line albumen glands. Whether these albumen gland changes are caused by decreased susceptibility to parasitism is yet to determined.

Animals↗
PubMed1994

The role of the plasma from platelet concentrates in transfusion reactions.

BACKGROUND: Febrile, nonhemolytic transfusion reactions are the most frequent adverse reactions to platelets. A number of observations argue against the widely held view that these reactions result from the interaction between antileukocyte antibodies in the recipient and leukocytes in the platelet product. We sought to determine whether substances in the plasma or the cells in the product cause reactions to transfused platelets. METHODS: We separated standard platelet concentrates into their plasma and cellular components and then transfused both portions in random order. Patients were monitored for reactions during all transfusions. Before each transfusion, the concentration of cytokines (interleukin-1 beta and interleukin-6) was measured in the platelet products. Studies were also performed on the platelet products to determine the effect of storage on the concentration of cytokines. RESULTS: Sixty-four pairs of platelet-product components (the plasma supernatant and the cells) were administered to 12 patients. There were 20 reactions to the plasma supernatant and 6 reactions to the cells (chi-square = 6.50, P = 0.009). Eight transfusions were associated with reactions to both products. The plasma component was more likely to cause severe reactions than the cells (chi-square = 9.6, P < 0.01). A strong positive correlation was observed between the reactions and the concentration of interleukin-1 beta and interleukin-6 in the plasma supernatant (P < 0.001 and P = 0.034, respectively). In vitro studies demonstrated that interleukin-1 beta and interleukin-6 concentrations rise progressively in stored platelets and that these concentrations are related to the leukocyte count in the platelet product. CONCLUSIONS: Bioreactive substances in the plasma supernatant of the platelet product cause most febrile reactions associated with platelet transfusions. Removing the plasma supernatant before transfusion can minimize or prevent these reactions.

Adult↗
PubMed1994

A comparison of the endotoxin-retentive abilities of two '96-h' in-line intravenous filters.

The ability of two in-line intravenous filters, the Pall Intravenous Set Saver Filter ELD96 and the Codan I.V. S SET-P, to retain endotoxin released by Pseudomonas aeruginosa during filtration of amino-acid-based parenteral nutrition (PN) solutions was investigated. When challenged with 10(8) cells of P. aeruginosa during simulated clinical PN infusion, the Pall ELD96 was shown to be capable of providing an effluent free of detectable endotoxin (< 0.3125 EUE/ml). In contrast, the Codan I.V. S SET-P allowed significant amounts of endotoxin to pass through.

Catheterization, Peripheral↗
PubMed1993

Immunomodulatory properties of diazepam-binding inhibitor: effect on human interleukin-6 secretion, lymphocyte proliferation and natural killer cell activity in vitro.

We have examined the influence of diazepam binding inhibitor (octadecaneuro-peptide, DBI33-50) on cell mediated immune responses including LPS-stimulated monocyte IL-6 secretion, PHA induced lymphocyte proliferation and NK cell function in humans. All studies were performed in vitro on isolated human peripheral blood mononuclear cells in the absence or presence of synthetic DBI33-50. It has been shown that DBI33-50, in concentration between 10(-6)-10(-8) M, enhances the LPS-induced secretion of IL-6, as determined by specific bioassay for this monokine. On the other hand DBI33-50 (10(-6)-10(-12) M), had no significant effect on either PHA-induced lymphocyte proliferation or NK cell function. This data suggests a possible immunomodulatory role for DBI33-50 as an endogenous neuropeptide, which stimulates IL-6 secretion by human monocytes.

Adult↗
PubMed1993

Regulation of IL-6 and the hepatic IL-6 receptor in acute inflammation in vivo.

The serum levels of interleukin 6 (IL-6) and the expression (mRNA) of the 80 kDa IL-6 receptor (IL-6R) were examined in three different models of acute inflammation. Rats were treated with either Freund's complete adjuvant (FA) via intraperitoneal injection, LPS via intravenous injection, or turpentine via subcutaneous injection. Using bio- and specific immunoassays, rat serum levels of IL-6, corticosterone, and acute phase proteins were quantified. LPS treatment induced the quickest and greatest serum IL-6 response (> 100 ng/ml within 3 h). In comparison, sera from turpentine and FA-treated rats contained much lower levels of IL-6 activity (< 10 ng/ml). Serum corticosterone levels increased by 3 h after injection in all three models, and equivalent raised serum levels of acute phase proteins were detected within 12-24 h. The expression of IL-6 receptor mRNA in hepatocytes increased markedly as early as 3 h after treatment and message levels began to decline by 6-12 h in all three models. To analyze the individual effects of raised corticosterone and IL-6 on the expression of hepatic IL-6R mRNA, rats were injected with either dexamethasone (Dex) or purified recombinant rat IL-6 (rIL-6) via intraperitoneal injection. Rats injected with rIL-6 showed highly induced IL-6R mRNA levels as early as 1 h after injection, and Dex-injected rats showed a significant but less dramatic rise in IL-6R message levels. Dex- or rIL-6-injected rats demonstrated a distinct profile of acute phase protein response different from that seen in the three experimental models. Regulation of IL-6R gene expression in the liver in vivo depends on a complex interaction between the hepatocyte and a combination of cytokines and other hormones.

Acute Disease↗
PubMed1993

Significance of antibody to hepatitis B core antigen in blood donors as determined by their serologic response to hepatitis B vaccine.

Because large numbers of volunteer blood donors may be disqualified for "false-positive" results on tests for antibody to hepatitis B core antigen (anti-HBc), a more specific definition of anti-HBc enzyme immunoassay (EIA)-reactive was evaluated, including only those donor samples that were "strongly" reactive (sample-to-cutoff absorbance ratio, < 0.45). Results using this definition and other anti-HBc test methods were compared to the serologic response (antibody to hepatitis B surface antigen [anti-HBsAg]) to hepatitis B vaccination. Fifty-eight volunteer blood donors who had previously been deferred as donors, because of reactive anti-HBc tests (all other blood screening tests were negative, including those for HBsAg and anti-HBsAg) on two occasions, were vaccinated for hepatitis B. It was assumed that an anamnestic response to vaccine indicated past infection with hepatitis B, while a primary response to vaccine indicated lack of past infection. One (2%) of 43 donors with a historically "weak" anti-HBc (reactive absorbance ratio, > or = 0.45) had an anamnestic response to vaccine, compared to 8 (53%) of 15 with historically "strong" anti-HBc (reactive absorbance ratio, < 0.45) (p < 0.005). Anti-HBc testing using the microparticle EIA method also correlated well with hepatitis B vaccination results. The use of a narrower definition of "reactive" for anti-HBc EIA testing yielded much more specific, but slightly less sensitive, results.

Blood Donors↗
PubMed1993

Immunological relationships of NGF, BDNF, and NT-3: recognition and functional inhibition by antibodies to NGF.

Polyclonal antibodies raised against mouse 2.5S NGF (mNGF) and against synthetic peptides made from hydrophilic portions of mNGF have been used to compare the immunological properties of mNGF, human recombinant brain-derived neurotrophic factor (hrBDNF), and human recombinant neurotrophin-3 (hrNT-3). Affinity-isolated antibodies raised against intact mNGF reacted with all three neurotrophins when tested by ELISA and totally or partially blocked the bioactivities of the proteins in survival assays of embryonic chicken sensory and sympathetic neurons. On Western blots, mNGF antibodies reacted with all three neurotrophins but less well with hrBDNF and hrNT-3 than with mNGF. Antibodies to hydrophilic peptides within NGF (amino acids 23-35, 59-67, 69-79, and 91-100) showed partial reactivity with some but not all of the neurotrophins when tested by ELISA and on Western blots. The peptide antibodies were also selectively effective in reducing the survival-promoting activity of the neurotrophins on sensory neurons. Results show that mNGF, hrBDNF, and hrNT-3 are immunologically related proteins and that mNGF antibodies react also with other members of the neurotrophin family.

Amino Acid Sequence↗
PubMed1992

Identification of a repetitive element in the snail Biomphalaria glabrata: relationship to the reverse transcriptase-encoding sequence in LINE-1 transposons.

BamHI-digested Biomphalaria glabrata DNA contains a repetitive 2.0-kb fragment which is readily discernible by ethidium bromide staining. We present evidence that this repetitive element is related at both the nucleotide and amino acid levels to long interspersed nuclear element (LINE)-like transposons. Although comparable elements have been described in several invertebrates, this is the first report of a molluscan homologue. In common with LINE transposons, an open reading frame in the B. glabrata element shows significant homology to reverse transcriptase--a feature believed to allow the dissemination of these elements in the eukaryotic genome.

Amino Acid Sequence↗
PubMed1992

Functional aphonia in young people.

The study reviewed the case histories of 14 young aphonics. A questionnaire was completed by the five speech therapists involved with these cases. The patients were all initially examined by E.N.T. specialists and then treated by speech therapy. All the patients were 'cured' by speech therapy, that is the voice returned to its premorbid state. This study looks at common characteristics of presentation, different approaches to management, and the patterns of voice return.

Adolescent↗