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Biomedical subjects

W Longley

Publications and source records attributed to W Longley.

At least 19 recordsLinked to original sources
PubMed1992

Environmental risk factors for Alzheimer's disease: their relationship to age of onset and to familial or sporadic types.

Data from a case-control study of Alzheimer's disease (AD) were analysed in relation to age of onset and familial/sporadic status. The analyses were restricted to environmental exposures which might injure the brain. Later-onset AD was found to be positively associated with starvation/malnutrition and with nose-picking and negatively with analgesics, while earlier-onset was associated with physical underactivity and nervous breakdown more than 10 years before. Sporadic AD was associated with starvation/malnutrition and with head injury. These analyses merit replication in other large case-control studies of AD.

Age Factors↗
PubMed1990

A case-control study of Alzheimer's disease in Australia.

We conducted a case-control study of clinically diagnosed Alzheimer's disease (AD) on 170 cases aged 52 to 96 years, and 170 controls matched for age, sex and, where possible, the general practice of origin. Trained lay interviewers naive to the hypotheses and to the clinical status of the elderly person carried out risk-factor interviews with informants. Significant odds ratios were found for 4 variables: a history of either dementia, probable AD, or Down's syndrome in a 1st-degree relative, and underactivity as a behavioral trait in both the recent and more distant past. Previously reported or suggested associations not confirmed by this study include head injury, starvation, thyroid disease, analgesic abuse, antacid use (aluminum exposure), alcohol abuse, smoking, and being left-handed.

Aged↗
PubMed1989

Monozygotic twins discordant for Alzheimer's disease.

We identified 3 pairs of monozygotic twins discordant for probable Alzheimer's disease from a twin register and found no systematic differences in potential risk factor exposures between affected and unaffected twins. Such cases predict a role for environmental factors in the etiology or clinical onset of Alzheimer's disease.

Aged↗
PubMed1985

Medial hypothalamic and medial accumbens lesions which induce mouse killing enhance biting and attacks on inanimate objects.

The response to a series of objects by rats with lesions of the medial hypothalamus or medial accumbens was compared to that of spontaneous killing rats and sham-lesioned nonkillers. When exposed sequentially to a piece of wood, a wad of cotton, or a freshly killed mouse, there were no differences in the intensity of the initial response toward the stimulus object by spontaneous mouse killing rats and lesioned animals that were later shown to kill mice. However, lesioned animals did spend more time biting these objects and were more likely than spontaneous killers to attack the objects if they were moved about by the experimenter. When allowed to kill mice, there were no differences in the intensity of the attack by spontaneous and lesion-induced killers but again the lesioned animals bit the prey more following the kill and were more likely to attack the dead prey when it was moved by the experimenter. Sham-lesioned nonkillers spent less time biting the stimulus objects than spontaneous killers and never attacked the objects when they were moved by the experimenter. It is argued that the killing of lesioned animals is homologous to that of spontaneous killers but that the lesioned animals exhibit most components of the predatory behavior to an exaggerated degree.

Aggression↗
PubMed1985

Group rearing abolishes hyperdefensiveness induced in weanling rats by lateral septal or medial accumbens lesions but not by medial hypothalamic lesions.

Lesions of the medial hypothalamus, medial accumbens, or septum were made in 21- to 25-day-old male hooded rats. Half of the animals in each group were subsequently reared in groups and the other half in isolation. When tested for defensiveness toward the experimenter at 31, 34, and 37 days postoperatively, rats with medial hypothalamic lesions were most hyperdefensive toward the experimenter if reared in isolation but were significantly more defensive than sham-lesioned animals even when reared in groups. Rats with septal lesions were significantly more defensive than sham-lesioned animals only when reared in isolation while rats with medial accumbens lesions were not different from controls whether reared individually or in groups. These results suggest that the medial hypothalamus may have a special importance in determining temperament since the hyperdefensiveness that results from interference with its functioning is resistant to experiential remediation.

Aggression↗
PubMed1984

A comparison of prey eating by spontaneous mouse killing rats and rats with lateral septal, medial accumbens, or medial hypothalamic lesions.

Rats with lesions of the medial hypothalamus and spontaneous mouse killing rats were tested for mouse and rat pup killing in their living cages 1 and 3 days postoperatively. The lesioned and spontaneous killers did not differ significantly in amount of prey eaten within 10 min following a mouse kill on either Day 1 or 3 postoperatively. Both groups ate significantly more of the prey than did sham-lesioned rats that were presented with a freshly killed mouse. When 4 hr was allowed for eating following a kill, rats with lesions of the lateral septum, medial accumbens, and medial hypothalamus each ate significantly more than spontaneous mouse killing rats. The greater prey eating by the lesioned animals is probably not the result of the prey being a highly palatable food since rats with medial hypothalamic lesions but not those with medial accumbens or septal lesions showed enhanced consumption of a sweetened lab chow over a 4 hr period. The quantitative similarity in the prey eating by spontaneous and lesion-induced mouse killers in the period immediately following the kill serves to further establish a relationship between these two kinds of killing. The greater eating that occurs in lesioned animals when a longer time is allowed for eating is consistent with other observations of excesses in the killing behavior of lesioned animals relative to spontaneous killers.

Animals↗
PubMed1984

Handling from weaning to adulthood does not prevent hyperdefensiveness induced by septal, medial accumbens, or medial hypothalamic lesions.

Weanling male hooded rats were handled or not handled for 10 min each day, 5 days/week, for 6 weeks. At the end of this time all animals received one of the following: a septal lesion, a medial accumbens lesion, a medial hypothalamic lesion, or a sham lesion. The animals were tested for defensiveness toward the experimenter on Days 3, 7, and 14 postoperatively. All behavioral testing was done blind. Each of the three lesions increased defensiveness toward the experimenter. However, with each lesion, there was no difference in the defensiveness scores of preoperatively handled and nonhandled animals at any of the postoperative test sessions while those of animals with medial hypothalamic lesions did not. These results are consistent with observations that hyperdefensiveness occurs in human subjects following tumors in each of these brain areas in spite of their familiarity with the situation in which they are observed. They contrast with observations that mouse killing induced by septal lesions is readily prevented by preoperative exposure to a mouse.

Age Factors↗
PubMed1980

A simple, combined diffractometer and scanning microdensitometer.

A simple device for densitometering electron micrographs or other transparencies by one-dimensional scanning is described. Micrographs of crystalline materials are oriented by means of their optical diffraction patterns displayed with a slightly modified microscope.

Densitometry↗
PubMed1969

Paramyosin: molecular length and assembly.

Paratnyosin paracrystails formned with divalent cations have a 725-angstrom axial period and show simple negative staining patterns in the electron microscope. The structure of the aggregates is interpreted in terms of an array of polar molecules about 1275 angstroms long, with "gaps" and "overlaps" in the molecular assembly. Antiparallel relatiotns between molecules lead to the assembly of paracrystals with opposite polarity at either end. Implications of the in vitro structure for filaments containing paramyosin in muscle are discussed.

Animals↗