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Biomedical subjects

R G Condon

Publications and source records attributed to R G Condon.

18 recordsLinked to original sources
PubMed1995

Puberty, pregnancy, and menopause: lifecycle acculturation in a Copper Inuit community.

In the past three decades Copper Inuit women have gone from a situation of family-centered births in tents and snowhouses, to community births in government-run nursing stations to hospital births hundreds of miles from home. This process, which has been well documented by John O'Neil, Patricia Kaufert and others, is one aspect of the medical acculturation of the Canadian Inuit. The present work demonstrates how this medical acculturation has profoundly affected both the quality and the character of information flow between generations regarding all life cycle processes from bith to puberty to menopause. This paper examines the changes in the transmission of cultural information about life processes for 3 generations of Inuit women in the Central Canadian Arctic village of Holman and will consider the historical and social roots of these changes. Among the findings of the authors is that both elderly and young women are relatively knowledgeable regarding issues related to reproductive health and are comfortable discussing these topics. Women in their middle years, however, appear to be less knowledgeable and often display discomfort with the subject.

Acculturation↗
PubMed1990

Adolescence and changing family relations in the Central Canadian Arctic.

This paper reports on a ten-year longitudinal study of adolescent development and socialization conducted in the Copper Inuit community of Holman. This research has documented how demographic, social, and economic changes have dramatically altered the patterning and sequencing of traditional Inuit life stages, thus giving rise to a prolonged adolescent life stage which was non-existent in the precontact period. At the same time, Inuit family relations have undergone drastic changes as a result of population increase, population concentration, access to government housing, introduction of formal schooling, and the availability of social subsides. Today, the Copper Inuit family has lost its focus as the primary agent of socialization and learning, and many young Inuit now spend most of their time within the context of a greatly expanded peer group which has gradually acquired the values and aspirations of the southern adolescent sub-culture. This paper will discuss the impact of these changing attitudes upon parent-child relations as well as the social adjustment problems experienced by young Inuit as they strive to find a place in the North's changing social landscape.

Adolescent↗
PubMed1979

Biosynthetic pathway leading to gentamicin C2b.

Incubation of Micromonospora purpurea SC 1210 (NRRL 5467) with L-[methyl-14C]methionine yielded [methyl-14C]gentamicin A and methyl-14C-labeled antibiotic JI-20A in a molar radioactivity ratio of 9:2. We did not isolate methyl-14C-labeled gentamicin X2, which was expected as an intermediate based on the biosynthetic pathways proposed by others. Addition of methyl-14C-labeled antibiotic JI-20A to M. purpurea SC 1124 (NRRL 8102) yielded [methyl-14C]-gentamicin C1a and [methyl-14C]gentamicin C2b in variable molar radioactivity ratios. These data do not support the biosynthetic pathway leading to gentamicin C2b proposed by Testa and Tilley.

Fermentation↗
PubMed1978

Method for qualitative determination of 2-deoxystreptamine.

We have developed a qualitative method to assay for the presence of 2-deoxystreptamine in hydrolysates of crude aminoglycoside preparations using a 2-deoxystreptamine-requiring idiotrophic mutant. The assay involves (i) incubation of a 2-deoxystreptamine-requiring mutant with 1 mg of a hydrolyzed preparation from a crude unknown antibiotic mixture per ml, and (ii) examination of the resultant incubation mixture for production of antibiotic(s) by disk assay.

Anti-Bacterial Agents↗
PubMed1978

Antibiotic biosynthesis by cofermentation of blocked mutants of two Micromonospora species.

Two aminocyclitol-negative Micromonospora mutants representing two different species, M. purpurea and M. inyoensis, and blocked at different steps in the biosynthetic pathway were paired and cofermented for the synthesis of antibiotics. The two blocked mutants were incapable of producing antibiotics alone except when 2-deoxystreptamine was added. When combined they produced gentamicins A, X(2), C(1a), and C(2b), which all have an amino group at the 2' position, and gentamicin B, which has a hydroxyl group at this position instead.

Anti-Bacterial Agents↗
PubMed1978

Uptake of (methyl-14C)-sisomicin and (methyl-14C)-gentamicin into bacterial cells.

Eight sensitive strains (two Staphylococcus aureus, two Escherichia coli, two Pseudomonas aeruginosa and two Klebsiella pneumoniae) and four resistant Pseudomonas aeruginosa strains were used to study uptake of sisomicin and gentamicin by the bacterial cells. In eleven out of the twelve organisms studied employing (methyl-14C)-sisomicin and (methyl-14C)-gentamicin, uptake of the former was found higher that that of the latter. In one organism, the uptake of the two antibiotics was similar. This higher uptake of sisomicin may help explain the superior potency of the antibiotic in relation to gentamicin.

Bacteria↗
PubMed1977

Biotransformation of sisomicin to gentamicin C2b.

Sisomicin was transformed to gentamicin C(2b) by Micromonospora rhodorangea NRRL 5326. The mechanisms involved in the biotransformation are the 6'-N-methylation and the (4'-5')-reduction. The progression of the methylation was followed by the isotope technique, but the reduction reaction was not monitored.

Gentamicins↗
PubMed1976

Formation of methylated and phosphorylated metabolites during the fermentation process of verdamicin.

In an attempt to understand the biosynthetic processes leading to the formation of verdamicin (end product), we have examined the patterns of the formation of methylated and phosphorylated metabolites, which resulted from either the addition of l-[methyl-(14)C]methionine or [(32)P]KH(2)PO(4) to the fermentation. Incorporation of label from l-[methyl-(14)C]methionine into the bioactive sisomicin, verdamicin, and the chromatographically polar components increased with the progression of time. Two methylated bioinactive metabolites were found in the culture broth after removal of the methylated bioactive metabolites. In contrast to the bioactive metabolites, incorporation of the methyl-(14)C label into the two methylated bioinactive metabolites decreased with the progression of time. A phosphorylated bioinactive metabolite (nonmethylated) was also found in the culture broth, fermented in the presence of [(32)P]KH(2)PO(4). The role of the phosphorylated metabolite in the biosynthesis of the bioactive metabolites cannot yet be explained.

Aminoglycosides↗
PubMed1976

Micromonospora-produced gentamicin components.

After the chromatographic separation of [methyl-(14)C]gentamicin major (C) components from a large-scale radioactive fermentation (Lee et al., 1974), [methyl-(14)C]gentamicin minor (polar) components (A, B, B(1), X(2), and G-418) were isolated from subsequent chromatography of the remaining antibiotic mixture. When l-[methyl-(14)C]methionine was added at the onset of biosynthesis of the gentamicin components, incorporation of label into the minor components preceded incorporation into the major components. Degradation occurred when [methyl-(14)C]gentamicin major components (C(1), C(2) and C(1)a) were added respectively to the gentamicin-producing culture medium and shaken.

Biodegradation, Environmental↗
PubMed1976

Micromonospora-produced sisomicin components.

A sisomicin fermentation carried out in the presence of (methyl-14C)-L-methionine resulted in a crude mixture, composed of methyl-14C-labeled sisomicin as a major component; and two 4''-C-desmethylsisomicin (66-40B and 66-40D) isomer-like components, an unidentified component and a gentamicin A-like antibiotic as minor components. When (methyl-14C)-L-methionine was added in an early stage of the fermentation (24 hours), incorporation of methyl-14C-label into polar components (e.g., gentamicin A-like antibiotic) preceded that into sisomicin. Chromatographic evidence for the bioconversion of (methyl-14C)-gentamicin A to a radioactive sisomicin-like product (possibly (3''-N-methyl-14C)-sisomicin) was seen, when a Micromonospora blocked mutant was incubated in the presence of the former antibiotic.

Anti-Bacterial Agents↗
PubMedDate not supplied

Biomass and aggregation analysis of human embryonic kidney 293 suspension cell cultures by particle size measurement.

A method has been developed to monitor the cell growth of aggregated human embryonic kidney 293 (HEK293) suspension cultures by measuring cumulative particle volume and the particle size distribution. This method employs a particle size analyzer that determines the size of individual particles by detecting their light obscuration (blockage) or scattering. Cell counts derived from the cumulative volume of the cell particle correlate well with manual cell counts from a hemacytometer at different stages of growth. This correlation was further confirmed by quantifying total cellular protein of the samples. Simultaneously, the aggregation state of the samples can also be monitored and mathematically described. Results from this study demonstrate that this simple and reproducible method allows the direct measurement of cumulative cell volume and the degree of cell aggregation, as well as an indirect assessment of cell counts.

Biomass↗