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Biomedical subjects

R S James

Publications and source records attributed to R S James.

9 recordsLinked to original sources
PubMed1995

Uniparental isodisomy 13 in a normal female due to transmission of a maternal t(13q13q).

Chromosomes from a normal 23-year-old, primigravid woman were examined at 10 weeks of gestation because of her mother's history: 8 miscarriages and two liveborn infants (the proposita and a brother who died at 3 days with multiple anomalies). Karyotypes of the proposita and her normal mother were 45,XX,t(13q13q). No evidence of mosaicism was encountered. When the proposita inherited the t(13q13q), she received two copies of 13q from her mother. Moreover, she and her mother shared the same homozygous pattern of alleles from 7 highly polymorphic microsatellite repeats localized along 13q. No evidence of paternal markers from 13 was detected, although biparental inheritance was demonstrated with DNA markers from chromosomes 2 and 17. Cytogenetic and molecular findings indicated that the proposita's chromosomal complement included mUPD 13q. The proposita's normal phenotype suggested that no maternally imprinted genes map to 13q.

Abortion, Habitual↗
PubMed1995

A search for uniparental disomy in carriers of supernumerary marker chromosomes.

As there is some evidence that individuals bearing supernumerary marker chromosomes (SMCs) might have an increased risk of being uniparentally disomic for the structurally normal homologues of the SMC, we made a systematic search for uniparental disomy of the autosomal homologues from which SMCs were derived. Of the 22 families studied, a biparental origin of the normal homologues was demonstrated in 21, and 1 case of paternal isodisomy of chromosome 6 was detected in the carrier of a supernumerary marker ring chromosome 6 which itself was of maternal origin. Our results confirm that uniparental disomy may be found in association with SMCs, but until more cases are studied we can only speculate on their frequency and the mechanism(s) which result in this phenomenon.

Chromosome Aberrations↗
PubMed1995

The mechanical properties of fast and slow skeletal muscles of the mouse in relation to their locomotory function.

The mechanical properties of soleus and extensor digitorum longus (EDL) muscles from the mouse were studied using the work loop technique. Under optimum conditions, the EDL produced a maximum mean power output of 107 W kg-1 at a cycle frequency of 10 Hz. In comparison, the maximum mean power output of the soleus was 34 W kg-1 at 5 Hz cycle frequency. Video analysis of mice determined the stride frequency range to be from 2.87 Hz at a walk to 8.23 Hz at a flat-out gallop, with the trot-to-gallop transition occurring at 5.89 Hz. In vivo EDL electromyogram (EMG) activity is recorded primarily during shortening and the muscle operates in a power-generating mode. The soleus is close to isometric when EMG activity is recorded, but mechanical activity persists into the shortening phase. Both muscles are likely to operate over cycle frequency ranges just below, or at, those yielding maximal power. Soleus and EDL produced maximal power output in vitro when operating at mean sarcomere lengths of 2.58 microns and 2.71 microns respectively. These lengths are slightly above the plateau of the length-force curve predicted for rat leg muscle (2.3-2.5 microns). The sarcomere length ranges used in vivo by the soleus and EDL were determined, by fixing muscles in the extreme active positions predicted from video and cine analysis, to be 2.28-2.57 microns and 2.49-2.88 microns respectively. These ranges are both close to those shown to yield maximum power output in vitro and to the plateau of the sarcomere length-force curve.

Animals↗
PubMed1994

Duplication of 16q22-->qter confirmed by fluorescence in situ hybridisation and molecular analysis.

We report a female infant with congenital dislocation of the knee and dysmorphic features including a prominent forehead, midface hypoplasia, and micrognathia. Fluorescence in situ hybridisation and PCR amplification of microsatellite repeats were used to show that she had a de novo unbalanced translocation resulting in partial trisomy for 16q and partial monosomy for 15q (46,XX, -15, tder(15)t(15;16)(q26.1;q22). The consequences of partial aneuploidy of 16q are discussed.

Abnormalities, Multiple↗
PubMed1994

Diaphragmatic herniae and translocations involving 8q22 in two patients.

Two girls with congenital diaphragmatic herniae are reported. Both were discovered to have a balanced reciprocal translocation involving 8q22.3. In one girl the translocation was de novo, in the other it was maternally inherited. Uniparental disomy was excluded in both. 8q22.3 may be the location of a gene affecting development of the diaphragm.

Chromosomes, Human, Pair 8↗
PubMed1990

Silicone plastinated pathology specimens and their teaching potential.

Plastination is a process of tissue preservation by impregnation with silicone polymers or epoxy resins. The resulting specimens are dry, odourless, durable, life-like, non-hazardous, maintenance-free, and do not deteriorate with time. The technique may be easily mastered by those with a basic knowledge of histology laboratory practice. A small-scale system is relatively inexpensive to establish and specimens are comparable in cost to traditional 'pots'. Plastinated specimens are a useful adjunct to the teaching of pathology, anatomy, radiology, and surgery, and are particularly suited to use in small groups. They are much preferred to conventional 'pots' by both students and teachers owing to their accessibility, superior illustrative powers, and comparative ease of interpretation.

Attitude of Health Personnel↗
PubMedDate not supplied

Entry into practice.

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American Nurses' Association↗