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Biomedical subjects

S Wood

Publications and source records attributed to S Wood.

At least 217 records · Page 12Linked to original sources
PubMed1988

A restriction-fragment-length difference detected by the anonymous probe DXS199 exhibits non-Mendelian inheritance.

Anonymous DNA probes were isolated from an X chromosome-enriched flow-sorted library. One of these probes, DXS199, identified a restriction-fragment difference that failed to show Mendelian segregation. All normal females were found to have two AvaII fragments of 6.5 kb and 6.0 kb, whereas all normal males had only the 6.5-kb fragment. DNA from a 49,XXXXY male was found to have both 6.0- and 6.5-kb AvaII fragments, in the same 3:1 ratio as seen in the inactive:active number of X chromosomes. This variant, which reflects a structural difference between active and inactive X chromosomes, is likely to be due to a methylation site on the active X chromosome.

DNA Restriction Enzymes↗
PubMed1988

Pancytopenia in a patient receiving home intravenous nutrition.

A patient is described who developed pancytopenia several months after home intravenous nutrition (IVN) was started following a major small bowel resection for volvulus. In the post-operative period his weight fell by about 15 kg to 45 kg. Bone marrow aspiration and leucokinetic studies were carried out which suggested that bone marrow failure was the cause of this patient's haematological abnormalities. Five of the 16 patients at St Mark's Hospital who are receiving home IVN were noted to have had transient neutropenia. In 3 of these patients significant weight loss was also noted in the few months preceding the development of neutropenia. It is suggested that there is an association between relative energy malnutrition and the development of the haematological abnormalities that have been observed. In the patient described here these abnormalities were prolonged.

Adolescent↗
PubMed1988

Linkage relationships and gene order around the locus for X-linked retinoschisis.

X-linked recessive retinoschisis (RS) is a hereditary disorder with variable clinical features. The main symptoms are poor sight; radial, cystic macula degeneration; and peripheral superficial retinal detachment. The disease is quite common in Finland, where at least 300 hemizygous males have been diagnosed. We used nine polymorphic DNA markers to study the localization of RS on the short arm of the X chromosome in 31 families comprising 88 affected persons. Two-point linkage results confirmed close linkage of the RS gene to the marker loci DXS43, DXS16, DXS207, and DXS41 and also revealed close linkage to the marker loci DXS197 and DXS9. Only one recombination was observed between DXS43 and RS in 59 informative meioses, giving a maximum lod score of 13.87 at the recombination fraction .02. No recombinations were observed between the RS locus and DXS9 and DXS197 (lods between 3 and 4), but at neither locus was the number of informative meioses sufficient to provide reliable estimates of recombination fractions. The most likely gene order on the basis of multilocus analysis was Xpter-DXS85-(DXS207,DXS43)-RS-DXS41-DXS 164-Xcen. Because multilocus linkage analysis indicated that the most probable location of RS is proximal to DXS207 and DXS43 and distal to DXS41, these three flanking markers are the closest and most informative markers currently available for carrier detection.

Female↗
PubMed1988

Parkinson Peter.

Explore the source record for details and available documents.

Aged↗
PubMed1987

A low-cost antifoam additive for agar-based culture media.

A highly effective, low-cost silicone-based antifoam emulsion is described which, at a final concentration of 100 ppm, prevents bubble formation during the preparation and dispensing of agar media. The compound is heat-stable, has a long shelf-life and offers considerable savings in cost by reduction in wastage of time and materials. It has no demonstrable deleterious effect on the growth of a wide range of pathogenic and commensal bacteria, or on antibiotic disc susceptibility testing, when examined using a range of different media.

Anti-Bacterial Agents↗
PubMed1987

Inverted tandem duplication generates a duplication deficiency of chromosome 8p.

An adult female with sever mental retardation and dysmorphic features is described. A de novo chromosomal aberration involving 8p was found. The karyotype was 46, XX, inv dup (8) (p12----p23.1). Dosage studies with the DNA probe D8S7, which is located at 8p23----8pter, showed that the patient was monosomic for this marker. Thus the de novo rearrangement generated a duplication-deficiency chromosome. The possible mechanisms of formation of this abnormal chromosome are discussed.

Abnormalities, Multiple↗
PubMed1987

Isolation and characterization of DNA probes from the short arm of the human X chromosome that detect restriction fragment length polymorphisms.

We have isolated 30 X chromosome specific probes from a flow-sorted library enriched for the human X chromosome. Hybridization to somatic cell hybrids containing different regions of the X chromosome localized nine of these probes to Xp. After testing 185 probe-enzyme combinations, three of the Xp probes were found to detect restriction fragment length polymorphisms.

Animals↗
PubMed1986

The effects of d-amphetamine, alpha-flupenthixol, and mesolimbic dopamine depletion on a test of attentional switching in the rat.

A test of attentional switching was devised for the rat in which it obtained sucrose reinforcement by an appropriate nose-poke response that discriminated which of two visual events terminated first, in a specially designed chamber. The effect of mesolimbic dopamine depletion (to 20% of control values) produced by infusions of 6-hydroxydopamine (6-OHDA) into the nucleus accumbens (N. Acc) on stable discrimination was measured alone and in the presence of a range of doses of d-amphetamine (0.4-2.3 mg/kg IP). The 6-OHDA lesion of the N. Acc impaired postoperative performance transiently by reducing choice accuracy and slowing response latency. By post-operative days 12-16, however, performance recovered to control levels and was not differentially affected by a manipulation of task difficulty. d-Amphetamine produced dose-dependent performance impairments, which were antagonised by the 6-OHDA treatment. In a second group of N. Acc lesioned rats, the neuroleptic alpha-flupenthixol (0.1-1.0 mg/kg) led to fewer trials being completed and longer latencies than in the sham-operated control group. The results are discussed in terms of the possible attentional mechanisms underlying the d-amphetamine-induced disruption of performance mediated by the N. Acc and of the implications for psychopathology resulting from possible dysfunction of this region.

Animals↗
PubMed1986

Pressure reversal of alphaxalone/alphadolone and methohexitone in tadpoles: evidence for different molecular sites for general anaesthesia.

Tadpoles were used to study quantitative interactions between high pressure and two intravenous anaesthetics, alphaxalone/alphadolone and methohexitone. The potencies of the two agents were decreased by high pressure but to different extents. The maximum effect was seen in the pressure range 70-130 atmospheres absolute (ATA). The increases in the normobaric anaesthetizing concentration (ED50) required at 100 ATA were alphaxalone/alphadolone:405 +/- 5 (s.d.)%; methohexitone:658 +/- 80 (s.d.)%. For both alphaxalone/alphadalone and methohexitone, the curves obtained when the increase in ED50 was plotted against increasing pressure showed plateaux at pressures above 70 ATA. These data support the concept of the two intravenous drugs causing general anaesthesia by the occupation of separate molecular 'sites' with different but finite capacities.

Amphibians↗
PubMed1986

The acoustical significance of tongue, lip, and larynx maneuvers in rounded palatal vowels.

The acoustical consequences of articulatory maneuvers of [y] are studied in model experiments in order to obtain insights into articulator programming and speech motor control by elucidating the role of each component maneuver of a speech segment in setting up vocal tract resonance conditions for the spectral features of the speech wave. The maneuvers of [y] are found to provide a maximum and stable plain-flat spectral contrast with [i]. The results can be generalized to different vocal tract sizes. Tongue retraction and larynx depression are rejected as compensations to counteract labial undershoot. Larynx depression is complementary to lip rounding and restores spectral sensitivity to palatal and pharyngeal tongue movements otherwise disturbed by the labial activity. Spectral sensitivity then remains the same for [i] and [y], and there is no need for separate compensation programs for each of these phones.

Humans↗