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Biomedical subjects

J Coleman

Publications and source records attributed to J Coleman.

At least 145 records · Page 8Linked to original sources
PubMed1985

Interspecies variability in propylene glycol dinitrate-induced methemoglobin formation.

Interspecies variability of propylene glycol dinitrate (PGDN)-induced methemoglobin formation was studied in vitro employing erythrocytes from four separate species. The net rate of methemoglobin formation was significantly different among species with dog greater than guinea pig greater than rat greater than or equal to human. This order of susceptibility was maintained in stroma-free hemolysates, indicating that interspecies variability was not a reflection of differences in red cell membrane permeability or intracellular transport of PGDN. The erythrocytic enzymes, catalase, superoxide dismutase, glutathione peroxidase, 6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, methemoglobin reductase, and glutathione-S-transferase, were assayed by adaptation of existing methods to a centrifugal analyzer. The above enzymes were removed from hemoglobin derived from each species and the order of susceptibility to PGDN-induced methemoglobin formation remained essentially the same with dog greater than guinea pig greater than human = rat. However, the net rate of PGDN-mediated oxidation of hemoglobin to methemoglobin increased in purified hemoglobin preparations from each species. These results demonstrate that there is species variability in the net rate of PGDN-mediated methemoglobin formation. Total enzyme activity in erythrocytes may contribute to reduction in the net rate of methemoglobin formation. However, the primary determinant of the net rate of methemoglobin formation induced by PGDN appears to be the structure of each hemoglobin molecule.

Animals↗
PubMed1985

Dual functions of the signal peptide in protein transfer across the membrane.

Most secretory proteins in both prokaryotic and eukaryotic cells are synthesized from a precursor with an amino-terminal extension of 20 to 25 amino acid residues called a signal peptide. These signal peptides are removed during translocation of the secretory proteins across the membrane. When two precursor structures are fused, the internalized second signal peptide was found to exert two different roles, depending upon either the distance between the two signal peptides, or whether the first signal peptide functions cotranslationally or posttranslationally. One role is to function as the usual signal peptide to translocate the protein downstream of the internal signal peptide. The other role is to function as a stop-transfer signal to create a transmembrane protein with the second signal peptide anchoring the protein in the membrane.

Bacterial Outer Membrane Proteins↗
PubMed1985

Successful chemotherapy for cystosarcoma phyllodes in a young woman.

Cystosarcoma phyllodes is a rare neoplasm of the breast. The tumor contains both stromal and epithelial elements. Local excision or simple mastectomy is usually curative. Most recurrences are local and can be controlled with excision. We treated a 23-year-old woman in whom disease had metastasized to the lungs with six courses of doxorubicin hydrochloride and cisplatin at three-week intervals and achieved complete remission.

Adult↗
PubMed1984

Differences in the mean fat cell diameter of males between 1 and 48 months of age.

The mean fat cell diameter was determined from measurements of abdominal adipose cells, obtained during inguinal hernia repair, of 126 white and 95 black males ranging in age from 1 through 48 months of age. The mean diameters of black and white subjects did not differ significantly, suggesting that differences in fatness among adults of these two ethnic groups have their origin beyond the age range of this study. The mean fat cell diameter increased through the 6-8 month age group, decreased until the end of the first year, and then levelled off through 48 months of age. Comparison of this curve with those for the triceps, subscapular, abdominal, and suprailiac skinfolds of the same subjects showed generally parallel courses except for the triceps, which continued to increase in size after the means of fat cell diameters and the other skinfolds had levelled off. Our data indicate that changes in body fatness on the trunk at least in the first 4 years of life may be accounted for by changes in fat cell size.

Abdominal Muscles↗
PubMed1984

The use of RNAs complementary to specific mRNAs to regulate the expression of individual bacterial genes.

A naturally occurring small RNA molecule ( micF RNA), complementary to the region encompassing the Shine-Dalgarno sequence and initiation codon of the ompF mRNA, is known to block the expression of that mRNA in E. coli. We have constructed a plasmid that produces a complementary RNA to the E. coli lpp mRNA (mic[Ipp] RNA). Induction of the mic(Ipp) gene efficiently blocked lipoprotein production and reduced the amount of lpp mRNA. Two mic(ompC) genes were similarly engineered and their expression was found to inhibit drastically production of OmpC. Analysis of several types of mic(ompA) genes suggests that micRNAs complementary to regions of the mRNA likely to come in contact with ribosomes were most effective. The novel capabilities of this artificial mic system provide great potential for application in both procaryotic and eucaryotic cells.

Bacterial Proteins↗
PubMed1984

Adolescent attitudes to authority.

This study is concerned with adolescent attitudes to authority. In particular the investigation focuses on notions of the ideal authority figure, attitudes to the sorts of conflicts experienced at home and in school, and on the types of resolutions to conflicts preferred by young people. Subjects were 43 adolescents from working class areas in outer London boroughs, all of whom were given a semistructured interview. Results indicated important differences in the amount of control required at home and in the school, and showed adolescents of 14 and 15 to have relatively little need for autonomy but a very considerable need for support from parents and teachers.

Adolescent↗
PubMed1983

The perfluorocarbon gases in the treatment of retinal detachment.

Four straight chain perfluorocarbon gases that had been studied in animals were tried in 30 patients. The larger volumes injected into patients made for extended disappearance times. Two milliliters of CF4 diminished to half volume in six days and had a total disappearance time of 16 days; 0.8 ml of C2F6 diminished to half volume in 10 days and had a disappearance time of 40 days; 1 ml of C3F8 diminished to half volume in 35 days and disappeared in 70 days; 0.6 ml of C4F10 diminished to half volume in 45 days and disappeared in 120 days. The expansion potential was estimated to be the same as measured in the animal model.

Animals↗
PubMed1983

Panic attacks and the dexamethasone suppression test.

Of 51 patients with panic attacks, 11.8% (7.8% with a correction factor) had a positive dexamethasone suppression test. This is significantly lower than the rate for melancholia. This difference suggests that panic attacks and major depression may be associated with different biological mechanisms.

Adult↗
PubMed1983

Puppetry and doll play as an adjunct to pediatric orthopaedics.

The loss of a considerable segment of body tissue is often psychologically more traumatic than is the actual surgery to the unprepared child. In an attempt to improve the preparation of the child for ablative surgery, as well as to facilitate the pre- and postoperative management of the pediatric patient and family, we have developed a system of doll play and puppetry to educate and prepare children for this type of surgery. Guilt feelings are minimized, an outlet for hostility is provided, and the ever present fear of the unknown is confronted and dealt with in a manner acceptable to the child. The nonthreatening role of this technique also helps alleviate parental fears and concerns. Our experience with this technique has confirmed its usefulness in the preoperative psychological preparation of young children facing amputation or major musculoskeletal procedures.

Body Image↗
PubMed1982

Development of the dorsal and ventral cochlear nuclei in rat and effects of acoustic deprivation.

Patterns of normal development of the rat dorsal and ventral cochlear nuclei (DCN, VCN) and the changes induced in the adult by postnatal acoustic deprivation were examined using volumetric determinations. VCN and DCN showed striking increases in size during the interval from postnatal days 10 to 16 which includes meatus opening. Sound deprivation from postnatal day 10 resulted in the most pronounced reduction in both DCN and VCN. The findings suggest a sensitive period during which structural development in the cochlear nuclei is influenced by acoustic stimuli.

Acoustic Stimulation↗
PubMed1982

A comparison of lateral peristriate and striate neocortical ablations in the rat.

The effects of striate, lateral peristriate and sham ablations upon the post-operative reacquisition of visual discriminations were studied in two experiments. The results of Experiment 1 indicated that lesions restricted to the lateral peristriate neocortex rendered the rat incapable of resolving an oblique stripe discrimination. Seven of the 9 rats with striate ablations were unable to form the discrimination. The histological findings indicated that the deficit following lateral peristriate injury was not due to interruption of the geniculostriate system. However, the behavioral impairment in destriate rats corresponded to the degree of unintentional injury in lateral peristriate neocortex, but not medial peristriate tissue. In Experiment 2, the effects of these lesions were studied upon the post-operative reacquisition of either a non-reversal or reversal of a preoperatively acquired brightness discrimination. Animals with striate damage demonstrated considerable savings on the non-reversed brightness discrimination, and they acquired the reversal at a rate equal to that seen in animals with sham ablations. Rats with peristriate ablations showed no savings on the non-reversed brightness habit, and they required more extensive training than both the striate and sham groups on the reversal. These findings suggest that the frequently reported loss of a preoperative brightness habit following large posterior neocortex ablations is due to damage in the lateral peristriate neocortex rather than damage of the geniculostriate system. These results, taken with other literature, suggest an important role of the lateral peristriate neocortex in visuospatial sensory function.

Animals↗
PubMed1981

An analysis of different techniques for distal hypospadias repair: the price of perfection.

We discuss the risks of total surgical correction of distal hypospadias with chordee, review 42 such cases and analyze 4 common surgical procedures that were used. The over-all complication rate was 16.6 per cent (7 of 42), with 9.5 per cent (4 of 42) of the cases requiring addition urethral reconstruction. All complications occurred following procedures designed to extend the urethral meatus to the tip of the glans (Horton-Devine 5 of 15 and Ombrédanne 2 of 8). In contrast, no complications occurred following urethral advancement or Allen-Spence repairs (0 of 19). The physician and family should be aware of the increased risk attendant with total anatomical urethral correction in contrast to less extensive surgery, which gives an excellent functional result with minimal risk.

Adolescent↗
PubMed1981

Organization of thalamic projections to visual cortex in opossum.

Projections from visual thalamus to posterior cortex of the Virginia opossum revealed by retrograde transport of horseradish peroxidase show a specific and orderly pattern. The lateral geniculate nucleus projects only to cortical area 17, while a lateral sector of the lateral posterior nucleus sends afferents both to area 17 and 18. Area 19 receives input from the lateral intermediate nucleus; the caudomedial sector of the lateral posterior nucleus projects to the anterior and posterolateral areas of cortex. These features are generalized to other mammals to include thalamic input differentially derived from retinal, tectal, pretectal and cortical sources.

Animals↗