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Biomedical subjects

C Collins

Publications and source records attributed to C Collins.

At least 199 records · Page 11Linked to original sources
PubMed1989

Differential glycosylation of polymeric and monomeric IgM.

A small fraction of normal IgM is secreted as monomers rather than polymers. We show here that the mu chains of monomeric IgM are glycosylated differently from the mu chains of polymeric IgM and are comparable in their glycosylation to the mu chains from mutant hybridoma cell lines which produce predominantly monomeric IgM. The difference in glycosylation between monomer and polymer mu chains is due to differences in the terminal processing of their oligosaccharides. The glycosylation of the mutant mu chains is not itself responsible for the block in IgM polymer formation.

1-Deoxynojirimycin↗
PubMed1989

The response of young, non-sexually abused children to anatomically correct dolls.

Ninety-one children aged 3-6 yrs were observed and video-recorded playing with the anatomically correct dolls in unstructured play settings. Parental permission had been obtained. The children's emotional, behavioural and overall play responses were rated. Whilst the dolls' difference from other dolls was clearly noticed, they did not traumatise the children, most of whom incorporated the dolls in imaginative play. Only five children's play with the dolls showed any sexualized quality, in three the source of sexual knowledge becoming apparent. Whereas the absence of sexualized play does not reliably exclude abuse, we suggest that explicit sexual play with the dolls may well arise from previous exposure to explicit sexual information or activity.

Child↗
PubMed1989

Non-random association between alleles detected at D4S95 and D4S98 and the Huntington's disease gene.

Analysis of many families with linked DNA markers has provided support for the Huntington's disease (HD) gene being close to the telomere on the short arm of chromosome 4. However, analysis of recombination events in particular families has provided conflicting results about the precise location of the HD gene relative to these closely linked DNA markers. Here we report an investigation of linkage disequilibrium between six DNA markers and the HD gene in 75 separate families of varied ancestry. We show significant non-random association between alleles detected at D4S95 and D4S98 and the mutant gene. These data suggest that it may be possible to construct high and low risk haplotypes, which may be helpful in DNA analysis and genetic counselling for HD, and represent independent evidence that the gene for HD is centromeric to more distally located DNA markers such as D4S90. This information may be helpful in defining a strategy to clone the gene for HD based on its location in the human genome.

Alleles↗
PubMed1989

Immunoglobulin molecular genetics: the prospects for mutational analysis of the chromosomal immunoglobulin genes.

Homologous recombination between transferred and chromosomal DNA can be used to effect precise, predetermined modifications of the chromosomal genes. Ultimately this phenomenon should allow the assessment of genetic regulatory elements as they function in the normal chromosomal environment. We have previously described a system for isolating mutant hybridoma cells that are defective in immunoglobulin (Ig) production, with a view toward using these mutants to define cis-acting elements that influence Ig gene expression. Here we describe results that indicate that homologous recombination between transferred and chromosomal Ig genes can be used to map Ig mutations by marker rescue.

Animals↗
PubMed1989

Linkages between immunization and breastfeeding promotion programs.

Breastfeeding promotion and immunization are important interventions of child survival programs, especially in developing countries. Linkages between breastfeeding promotion programs and the Expanded Programme on Immunization (EPI) in developing countries mean that health care workers can make use of every contact with the mother and child to reinforce the educational messages of both programs. Breastfeeding does not interfere with vaccinations administered in accordance with the routine schedule recommended by the EPI Global Advisory Group for use in developing countries. Breastfeeding benefits the EPI and the EPI also benefits breastfeeding. The maximum reduction of morbidity and mortality will be achieved when all child survival interventions are applied in a balanced, complementary manner as envisaged in the concept of primary health care.

Breast Feeding↗
PubMed1988

Bicarbonate and fast-twitch muscle: evidence for a major role in pH regulation.

Internal pH (pHi) was analyzed in rat extensor digitorum longus (Edl) muscle at 30 degrees C with single-barrel liquid ion-selective electrodes. Average pHi in 284 cells was 7.197 +/- 0.006. Increases in CO2 from nominally 0 to 5% produced an acidification from which recovery took place. In different groups of cells, recovery from the 5% CO2 acidification was significantly inhibited by 100 microM 4,4' diisothiocyanatostilbene 2,2' disulfonic acid (DIDS), Cl removal, Na removal and 2 mM amiloride. Prepulsing with 20 mM NH4 in the presence of CO2/HCO3 typically reduced pHi to only about neutral, whereas 50 mM reduced pHi to 6.7-6.8. In the nominal absence of CO2/HCO3, 20 mM NH4 reduced pHi to about 6.7 from which recovery took place at about 58% of the rate seen in different cells in the presence of CO2/HCO3. In the presence of CO2/HCO3, cells prepulsed with 50 mM NH4 had fully recovered to an average pHi of 7.22 +/- 0.04 about 90 min after removal of NH4. However, 90 min after removal of 20 mM NH4 in the absence of CO2/HCO3, average pHi was significantly less (7.05 +/- 0.03). Intrinsic buffering capacity (beta i) was obtained during pulses of CO2, acetic acid or after an NH4 pulse. beta i was significantly reduced in the absence of HCO3, Cl or Na and HCO3. The data provide significant support for an important role of HCO3 in the control of pHi in fast-twitch muscle.

Animals↗
PubMed1988

Fluorescence in situ hybridization with human chromosome-specific libraries: detection of trisomy 21 and translocations of chromosome 4.

Chromosomes can be specifically stained in metaphase spreads and interphase nuclei by in situ hybridization with entire chromosome-specific DNA libraries. Unlabeled human genomic DNA is used to inhibit the hybridization of sequences in the library that bind to multiple chromosomes. The target chromosome can be made at least 20 times brighter per unit length than the others. Trisomy 21 and translocations involving chromosome 4 can be detected in metaphase spreads and interphase nuclei by using this technique.

Cells, Cultured↗
PubMed1988

Polyamine levels in petunia genotypes with normal and abnormal floral morphologies.

We characterized the polyamine pathway in Petunia hybrida genotypes that were either wild type or that had been identified as having altered floral morphology. Analysis of four normal morphology lines revealed two patterns of endogenous levels of putrescine and arginine decarboxylase: two with higher levels of putrescine, two with lower levels of putrescine. Analysis of F1 and backcross progeny between high putrescine and low putrescine strains is consistent with their differences being due to a dominant allele for low putrescine content and arginine decarboxylase activity. Four Petunia mutants with floral morphology changes were also screened. One of these mutants, alf, showed high levels of putrescine and high levels of arginine decarboxylase late in development; these high levels were found whether the alf line was present in either of the two types of normal morphology genetic backgrounds that had been characterized.

Journal Article↗
PubMed1988

Transitional cell carcinoma of the urinary bladder: histologic clearance with combined 5-FU chemotherapy and radiation therapy. Preliminary results of a bladder-preservation study.

Fourteen patients with transitional cell carcinoma of the urinary bladder were treated with 4,000 cGy of pelvic irradiation concurrent with two 96-hour infusions of 5-fluorouracil (5-FU). Three weeks after completion of this regimen, patients underwent repeat cystoscopy and deep-muscle biopsy at the site of their original neoplasms. Eight of 14 (57%) had no tumor left in the biopsy specimen, and they received an additional course of chemotherapy and radiation therapy to a total dose of 4,400 cGy to the pelvis and 6,000 cGy to the bladder. Five of the 14 had residual tumor in the biopsy specimen (one did not undergo biopsy) and went on to planned cystectomy. Two of the five had no tumor in the cystectomy specimen. Overall, ten of the 14 patients (71%) have been downstaged to a condition of P0 (no tumor) following 4,000 cGy and two courses of 5-FU. Of eight patients with retained bladders, seven remain well at a median follow-up of 7 months. At a range of follow-up of 3-21 months and a median of 7 months, 13 of 14 patients remain tumor-free. This regimen results in a greater percentage of downstaging than conventional irradiation alone, and may allow bladder preservation for those with radiation therapy- and chemotherapy-responsive tumors.

Adult↗
PubMed1988

Influence of dose and duration of infusion of interleukin-2 on toxicity and immunomodulation.

The purpose of this study was to investigate the effect of dose and duration of infusion of recombinant interleukin-2 (IL-2) on toxicity and immunomodulation. In a phase I/II study, IL-2 was administered intravenously (IV) daily for five consecutive days every other week for 4 weeks of treatment to 23 patients with progressive melanoma, renal, colon, or ovarian cancer by one of four regimens: groups I and II received 3 X 10(5) U/m2/d by two-hour or 24-hour infusion, respectively; groups III and IV received 3 X 10(6) U/m2/d by two-hour or 24-hour infusion, respectively. In a subsequent study, six patients (group V) received a single priming cycle of daily IL-2 for five days at 3 X 10(6) U/m2/d in divided 15-minute infusions every eight hours, before undergoing leukapheresis for lymphokine-activated killer (LAK) cell generation. Toxicity was mild with 3 X 10(5) U/m2/d, but severe chills and fever, moderate hypotension (not requiring IV pressors), and weight gain were observed with 3 X 10(6) U/m2/d. Toxicity was also related to the duration of infusion. In group IV (continuous infusion), fluid retention, weight gain, and azotemia were more frequent and severe than in groups III or V, in which the same total dose was administered by two-hour infusion or in three divided 15-minute infusions. IL-2 induced rebound lymphocytosis, which was directly dose-related and significantly higher in group IV (continuous infusion) than in groups III or V. Dramatic increases in the percentage and absolute number of cells expressing the IL-2 receptor were also most pronounced in group IV. With the higher dose of IL-2, LAK cells appeared in the circulation, and natural killer (NK) cytotoxicity was augmented. The results showed that the toxicity and immunomodulation by IL-2 are dose-dependent and are maximal by continuous infusion compared with two-hour or divided every eight hours infusions.

Adult↗
PubMed1988

Mania associated with small cell carcinoma of the lung.

This paper describes a case of small cell carcinoma of the lung with ectopic adrenocorticotropic hormone (ACTH) production which presented with mania. The association between manic syndromes and the various forms of glucocorticoid or ACTH excess is discussed.

ACTH Syndrome, Ectopic↗
PubMed1988

The management of massive haemorrhage.

Determined appropriate treatment of massive haemorrhage can reduce complications and save lives, yet failure to recognize or rectify acute blood loss undoubtedly still contributes to preventable hospital mortality. Anticipation and organization are the keys to improvement.

Blood Volume↗
PubMed1987

Recombinant interleukin 2 toxicity, pharmacokinetics, and immunomodulatory effects in a phase I trial.

Twenty-two patients with refractory malignancies were treated with four escalating weekly doses of recombinant interleukin 2 (IL2), given either i.v. by 2- or 24-h infusion, or s.c. A 1-wk washout period between each dose of IL2 was provided for the evaluation for pharmacokinetic and immunomodulatory effects. The maximum i.v. dose was 30 X 10(6) units; the dose-limiting toxicities were fever, flu-like symptoms, and hypotension. The maximum s.c. dose was 3 X 10(6) because of volume limitations with s.c. injection. No tumor regression was seen. During infusions of 3 X 10(6) units over 2 h or 24 h, serum IL2 levels greater than or equal to 223 units/ml or 16 units/ml were maintained, respectively; with s.c. injection of 3 X 10(6) units, levels greater than 20 units/ml were maintained for 9 h. Marked lymphopenia was observed 24 h after the initiation of IL2 doses which was completely reversible when measured prior to the next dose. The lymphopenia was nonselective; T- and B-lymphocytes decreased in an IL2 dose-dependent manner, without consistent change in the OKT4:OKT8 ratio. No change was detected in monocyte expression of HLA-Dr or T-cell expression of the IL2 receptor. The in vitro generation of lymphokine-activated killer cytotoxicity decreased sharply and transiently shortly after i.v. doses. Mitogen responsiveness, delayed-type hypersensitivity, natural killer cytotoxicity, and mixed-lymphocyte reactivity were unchanged or decreased transiently shortly after IL2 doses. These studies help define the bioavailability of IL2 by i.v. or s.c. routes, and they will aid in the design of studies utilizing daily doses of IL2.

Antibodies↗
PubMed1987

Complement activation by IgM: evidence for the importance of the third constant domain of the mu heavy chain.

We have isolated and analyzed the DNA encoding the mu heavy chain constant region of a mutant IgM which is defective in initiating complement-dependent cytolysis. By assaying the expression of mu genes which were constructed in vivo from mutant and normal gene segments, we have mapped the mutation into a 555-base pair segment. In this segment there is one nucleotide change, such that the mutant mu gene encodes serine rather than the normal proline at amino acid position 436 in the third constant domain. We have used site-directed mutagenesis to revert this mutation to the normal sequence and shown that this substitution results in the production of IgM with the normal phenotype.

Amino Acid Sequence↗
PubMed1987

Subcutaneous recombinant gamma interferon in cancer patients: toxicity, pharmacokinetics, and immunomodulatory effects.

Recombinant gamma interferon (r gamma-IFN) was administered s.c. daily to 26 patients with advanced cancer. Patients were assigned to one of six doses: 0.5, 1, 2, 4, 6, or 8 million units (MU)/m2 per d. The major toxicities were an influenza-like syndrome and fever, seen in all patients. Dose limiting toxicity occurred in 4 of 4 patients treated at 8 MU/m2. One patient with nodular poorly differentiated lymphocytic lymphoma had a mixed response, and two patients with renal cell cancer have had stabilization of disease for greater than 10 and greater than 12 months. Pharmacokinetic analysis, by radioimmunoassay, revealed mean serum r gamma-IFN concentrations up to 17 ng/ml, with maximal serum levels noted 6 to 13 h after injection. In vivo immunomodulation was assessed by natural killer (NK) cytotoxicity, monocyte activation as determined by cell surface expression of HLA-Dr, and peripheral blood mononuclear cell phenotype analysis by flow cytometry. The mean T4/T8 ratio increased from 2.1 pretreatment to 4.1 after 24 h of treatment, but returned to baseline after 7 and 28 days of treatment. Augmentation of NK function was noted after 7 days of treatment. Monocyte cell surface expression of HLA-Dr increased after 28 days of treatment at the three lowest doses. In conclusion, daily s.c. r gamma-IFN can be easily administered on an outpatient basis with minimal local skin toxicity, results in prolonged serum levels, and is associated with immunological changes of potential antitumor significance. Further study of the in vivo immunomodulatory effects induced by r gamma-IFN is indicated to help define the optimal treatment regimen.

Adult↗