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Biomedical subjects

A Fox

Publications and source records attributed to A Fox.

At least 145 records · Page 8Linked to original sources
PubMed1987

Interobserver variation in computed tomography of the brain.

As part of the University of Western Ontario Dementia Study, the computed tomographic brain scans of 16 patients were reviewed by three neuroradiologists. The size of the ventricles and sulci were rated using a six-point scale. Infarction and white matter changes were assessed in accordance with specified criteria. The interobserver correlations in this small series were statistically significant in 17 of 20 items, and good or acceptable for infarction, leuko-araiosis, and ventricular size. It is suggested that the use of rigid criteria for the definition of abnormality helps to promote interobserver agreement.

Brain↗
PubMed1987

Vascular risk factors and leuko-araiosis.

Leuko-araiosis was found in 49 of 140 demented patients compared with 12 out of 110 control subjects. Thirty-one of 95 patients with dementia of the Alzheimer's type had leuko-araiosis. A history of stroke was four times more frequent in patients with leuko-araiosis than in those without leuko-araiosis (17.4% and 4.4%, respectively). It occurred in 25% of controls with leuko-araiosis compared with only 2% of those without leuko-araiosis. Mean systolic blood pressure was associated with leuko-araiosis. No association was found for diastolic blood pressure, myocardial infarction, angina, diabetes, or carotid bruits. On logistic regression analysis, the strong association between dementia and leuko-araiosis was mainly explained by a history of stroke. There are common factors in leuko-araiosis and stroke, but stroke alone does not account for leuko-araiosis.

Aged↗
PubMed1987

The effects of teacher intrusion on social play interactions between children with autism and their nonhandicapped peers.

This study investigated the effects of two levels of teacher intrusion upon the behavior of elementary age children with autism and nonhandicapped peers during dyadic play interactions occurring in two special education classrooms. High versus low levels of teacher intrusion were contrasted in a mixed between- and within-subjects design counterbalanced for order across the two conditions. There were few differences in behavior across the two conditions, though the low-intrusion condition was associated with higher levels of toy contact, appropriate and inappropriate play, and lower levels of spontaneous verbalizations by the students with autism. There was no difference in the occurrence of excess behavior by condition. Results are discussed with respect to future investigations of effective teacher mediation to prepare children for positive peer interactions.

Autistic Disorder↗
PubMed1987

Carbohydrate profiling of bacteria by gas chromatography-mass spectrometry: chemical derivatization and analytical pyrolysis.

Carbohydrate profiling by gas chromatography-mass spectrometry is a powerful tool for the identification and detection of bacteria. Its increasing applicability in the microbiology laboratory is illustrated by three examples. In the first, differentiation of legionellae by their sugar composition was determined with alditol acetate derivatization followed by selected- ion monitoring. In the second example, a carbohydrate pyrolysis product from Streptococcus agalactiae was used to differentiate group B streptococci from other Lancefield groups after direct sampling from culture plates. The third example employed the carbohydrates rhamnose and muramic acid as chemical markers for the direct detection of bacterial cell wall degradation products in mammalian tissues. The analysis of carbohydrate markers for bacteria by gas chromatography-mass spectrometry has great potential for use in clinical identification of isolated bacteria as well as in the rapid diagnosis of bacterial infections without prior culture.

Animals↗
PubMed1987

Elimination of group A streptococcal cell walls from mammalian tissues.

The precise levels in mammalian tissues of rhamnose (a constituent of the group-specific polysaccharide) and muramic acid (a constituent of peptidoglycan) at various times after systemic administration of streptococcal cell walls were noted for the first time. The extreme resistance of the streptococcal cell wall to degradation by mammalian enzymes can now be clearly appreciated. The results help explain the chronic nature of certain inflammatory diseases elicited by streptococcal cell wall debris.

Animals↗
PubMed1986

The significance of white matter lucencies on CT scan in relation to cognitive impairment.

As part of a prospective clinicopathological study a cohort of "normal" elderly volunteers (n = 110) has been investigated with CT scans, psychometric testing (Extended Scale for Dementia) and neurological examination. CT scans were evaluated by a neuroradiologist for the presence or absence of white matter lucencies (WML). WML were defined as patchy or diffuse areas of decreased attenuation involving only white matter and with no change in adjacent ventricles or sulci. The 12 subjects with WML had lower scores on the ESD than the 98 subjects without WML (mean ESD with WML 229.5 +/- 14; without WML 236.7 +/- 8.6, t-test p less than .01) and the difference remains significant even after adjusting for the possible confounding effects of age (ANCOVA, P less than .043).

Aged↗
PubMed1986

Immunoblot analysis of the serological response in invasive Trichosporon beigelii and Blastoschizomyces capitatus infections.

The serological response to Trichosporon sp. was examined by the immunoblot technique. Antibodies to a range of antigens (200 to 16 kilodaltons) were detectable in three patients with invasive Trichosporon beigelii or Blastoschizomyces capitatus infections and 10 uninfected controls. High levels of preexisting antibodies may contribute to the rarity of systemic infections.

Antibodies, Fungal↗
PubMed1986

Uveitis and arthritis induced by systemic injection of streptococcal cell walls.

A single injection of an aqueous suspension of group A streptococcal peptidoglycan-polysaccharide complexes (PG-PS) when injected intraperitoneally into Lewis rats induced a self-limiting bilateral uveitis with associated perpetuating polyarthritis. The uveitis was characterized clinically during the first 72 h by iritis and fibrin deposition. Acutely, there was infiltration of polymorphonuclear cells. The symptoms gradually subsided, and at the close of the experiment eyes were normally clinically and histologically. In contrast, perpetuating inflammation and severe tissue injury developed in the limb. Using an enzyme immunoassay with specificity for the group A streptococcal polysaccharide, the levels of PG-PS in tissues of animals that were killed 1 to 7 days post-injection were measured. The relative amounts of antigen in eye:limb:liver of PG-PS injected animals were 1:9:170. The differences in the amounts of antigen detected in the eye and limb may help explain the development of the acute uveitis in contrast to the perpetuating polyarthritis observed on PG-PS administration. The authors suggest that bacterial debris may act similarly in causing ocular inflammation in man.

Animals↗
PubMed1986

Serum lipoproteins in Israeli "Bnei Israel" Indians.

Serum lipoprotein concentrations differ markedly in the various ethnic groups which compose Israel's immigrant population. A group of subjects belonging to a community of "Bnei Israel" Indians, consisting of 21 women and 16 men between the ages of 30 and 60 years, was studied 10 years after immigration. The women had lipoprotein levels comparable with the Israeli-born population. The men had significantly lower mean cholesterol levels and significantly higher HDL/total cholesterol ratios and a tendency for lower triglycerides than an age-matched Israeli-born group, and a higher HDL/LDL cholesterol ratio than the women of the same origin. These results are consistent with the observed low incidence of coronary heart disease in Israeli Bnei Israel men who appear to have a "healthier" lipoprotein profile than the women in this community.

Adult↗
PubMed1985

Modifications in the alditol acetate method for analysis of muramic acid and other neutral and amino sugars by capillary gas chromatography-mass spectrometry with selected ion monitoring.

Two alditol acetate methods for the gas chromatographic (GC) analysis of neutral and amino sugars were compared. Following sodium borohydride reduction, one method uses methylimidazole as an acetylation catalyst without prior removal of water or borate salts and the other method uses sodium acetate after removal of borate and water. Depending on the acetylation conditions, muramic acid produced different derivatives. With methylimidazole, reliable derivatization of muramic acid was not possible, although other sugars derivatized reliably. With sodium acetate, all sugars tested were reproducibly derivatized. The utility of the sodium acetate method is shown by the trace GC-mass spectrometric analysis of muramic acid and rhamnose derived from bacterial peptidoglycan-polysaccharide complexes in mammalian tissue.

Acetylation↗
PubMed1985

The relationship of the nonstress test to gestational age.

Five hundred ninety-three nonstress tests were performed on 41 obstetric patients, at gestational ages ranging from 20 to 40 weeks. Diagnoses included 10 cases of prematurity, six cases of diabetes mellitus, five cases of collagen-vascular disease, five cases of poor obstetric history, three cases of cardiac arrhythmia, and one case each of asthma, polyhydramnios, leukemia, nonimmune fetal hydrops; and eight volunteers were without high-risk factors. All neonates had a 5-minute Apgar score greater than 8; 29 neonates weighed greater than or equal to 2500 gm, 12 weighed less than 2500 gm, and four weighed less than 1500 gm. One neonate died of prematurity, and one was small for gestational age. There were no congenital anomalies. There was a significant difference in the number of reactive nonstress tests and nonreactive nonstress tests between the 20- to 24-week, 24- to 28-week, 28- to 32-week, and 32- to 36-week gestational age groups. The increased incidence of nonreactive nonstress tests at earlier gestational ages may have clinical implications.

Adult↗
PubMed1985

A new definition of Alzheimer's disease: a hippocampal dementia.

Preliminary data support the hypothesis that the decline of all higher cognitive functions in senile dementia of the Alzheimer type is attributable to histopathological changes in the hippocampal formation, with or without neocortical neuronal lesions. Previous literature amply supports the critical role of this "locus minoris resistentiae" in memory processing and cognitive physiology. New observations include quantitative morphometric evaluations of the hippocampal formation from a longitudinal study of prospectively tested patients and histological and neurochemical data from patients with a clinical presentation consistent with typical Alzheimer's disease, in whom the only neuropathological abnormality was devastating nerve cell loss and gliosis in the hippocampi.

Aged↗
PubMed1985

Degradation of muramyl dipeptide by mammalian serum.

Muramyl dipeptide, N-acetylmuramyl-L-alanine-D-isoglutamine (MDP), is the minimal biologically active subunit of bacterial peptidoglycan and elicits an acute inflammation in vivo. We now report that MDP is degraded by normal rat serum into its constituents, N-acetylmuramic acid and L-alanine-D- isoglutamine. The dipeptide is further degraded into its components L-alanine and D-isoglutamine. These results may help to explain how inflammation elicited by MDP is terminated in vivo.

Acetylmuramyl-Alanyl-Isoglutamine↗