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Biomedical subjects

D Lee

Publications and source records attributed to D Lee.

At least 505 records · Page 28Linked to original sources
PubMed1988

Immunohistochemical study of 22 cases of thymoma.

The histological and clinical features of 22 thymomas were reviewed. Immunohistochemical studies were performed using antibodies to cytokeratins (CAM 5.2 and S29) and to desmosomal protein. The heterogeneity of staining patterns seen in the epithelial cells supported the concept of separating thymomas into cortical, medullary, or mixed groups. Interdigitating cells were identified by antibody to S100 protein, and these varied in number between different tumours. Clustering of interdigitating reticulum cells occurred in association with foci of mature lymphocytes which were shown by staining of the leucocyte common antigen (CD45). The extent to which this occurred was used to assess the degree of medullary differentiation within the thymomas and this was correlated with the histological and clinical features. The lymphocyte population of six of the thymomas was studied using a range of antibodies to T and B cells; this showed the presence of B lymphocytes in thymomas.

Adult↗
PubMed1988

Effect of increased arterial CO2 on fetal breathing and behavior in sheep.

We studied breathing and behavioral response to increased arterial CO2 (PaCO2) in 12 fetal sheep between 130 and 145 days of gestation. Of these 12 fetuses, 10 had an increase in PaCO2 through maternal rebreathing of CO2; in the other 2 fetuses CO2 was increased via an endotracheal tube and application of continuous distending airway pressure. We used our window technique to observe and videotape fetal behavior. The experiments consisted of recording breathing activity and behavior during resting conditions (1 low- and high-voltage ECoG cycle) and during administration of CO2. We measured electrocortical activity (ECoG), eye movements (EOG), electromyography of the diaphragm (EMGdi) and neck muscles, tracheal (Ptr), amniotic, and carotid arterial pressures. Administration of CO2 by the rebreathing technique produced an increase in the amplitude of breathing activity as reflected by an increase in Ptr from 5.0 +/- 0.6 to 12 +/- 1.9 mmHg (P less than 0.01) and an increase in SEMGdi from 32 +/- 4 to 77 +/- 8% max (P less than 0.001). Frequency increased due to a decrease in inspiratory (TI) and expiratory duration. Ptr/TI increased from 11.0 +/- 2.0 to 37.4 +/- 9.0 mmHg/s (P less than 0.05) and SEMGdi/TI increased from 67 +/- 7 to 221 +/- 28% max/s (P less than 0.001). Although the response was at times prolonged into the transitional high-voltage zone, it did not persist during established high-voltage ECoG.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Immunogenicity and allergenicity studies on two beta-lactam structures, a clavam, clavulanic acid, and a carbapenem: structure-activity relationships.

Two newer beta-lactam-containing structures, a clavam, clavulanic acid, and a carbapenem, MM22383, have been studied for their intrinsic immunogenicity and allergenicity. Clavulanic acid has a very low immunogenic and allergenic potential, in contrast to MM22383 which is a contact sensitiser in guinea pigs and an immunogen in rabbits. Evidence for the allergenic potential of MM22383 in man through occupational exposure is also presented. Consideration of the chemistry of these two compounds with respect to their reactivity with protein provides a rationale for the marked difference in their behaviour. The importance of stable hapten-protein conjugates and epitope density is discussed in relation to immunogenicity.

Adult↗
PubMed1988

Measurement of IgG subclasses in the sera of laboratory workers exposed to rats.

Human IgG antibody subclasses have been measured in the sera of workers exposed to rats, using a crude extract of rat urinary protein antigens, in an ELISA system. The antibody titres in individuals either with or without specific IgE were similar, with the exception of IgG4 where the mean level of this subclass was lower in those individuals with measurable titres of IgE (p less than 0.01). Symptomatic individuals, with specific IgE, also had lower titres of IgG4 than the corresponding asymptomatic, IgE-positive subjects (p less than 0.05). The frequency of positives in each subclass assay was similar in both groups. These findings suggest that higher levels of IgG4 may have a protective rôle.

Animals↗
PubMed1988

Cataloging blood alcohol level and alcohol consumption data in field settings: feasibility and findings.

A team of two female interviewers, two male interview assistants, and one or two additional male observers were stationed in front of targeted drinking establishments to survey individuals about their drinking practices and to collect blood alcohol levels (BALs) using portable breath testers. Of the 176 individuals asked to participate, 156 (88%) consented to be interviewed and 141 (90%) provided breath samples. Of those tested, 40 (29%) were legally intoxicated (BAL greater than or equal to 100 mg/dl) while 68 (49%) registered a BAL of 50 mg/dl or greater. The mean BAL was 72 mg/dl. Individuals reporting that they were going to drive had significantly lower BALs than those planning not to drive. Subjects who thought they were legally intoxicated, on average, had BALs greater than the legal level of intoxication, and BALs significantly greater than those who felt they were not intoxicated. These data suggest that the collection of BAL, in combination with self-reported alcohol data, is an important component of methodologically sound alcohol field research.

Adult↗
PubMed1988

Accuracy of Papanicolaou smears. Art or science?

We examined the relationship between various levels of experience and the ability to obtain adequate Papanicolaou smears as defined by the presence of endocervical cells. From July 1, 1984, through June 30, 1986, 16,360 cervical smears were evaluated for the presence of endocervical cells. Of those smears, 9,243 contained endocervical cells; 7,117 did not. The results were evaluated for seven groups of providers: professional staff, residents (postgraduate years 1-4), nurse practitioners and student nurse practitioners. The range of smears with endocervical cells for individual providers was 22.2-73.1%. Significant differences existed between all the groups. Longer training did not equate with greater skill in obtaining endocervical cells. Obtaining adequate smears appears to be as much an art as a science.

Adolescent↗
PubMed1988

Splenic pregnancy--case report.

Primary splenic pregnancy is the rarest form of extrauterine pregnancy. Only six cases have previously been documented, none of which occurred in North America. A case of this rare entity is presented in which a pregnancy was found to arise from the spleen, requiring splenectomy. In addition to the classic signs of a fulminant ruptured ectopic pregnancy, a history of upper abdominal pain was the only distinguishing feature.

Adult↗
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

Cognitive and neurologic findings in subjects with diffuse white matter lucencies on computed tomographic scan (leuko-araiosis).

As part of a prospective clinicopathologic study, a cohort of 105 "normal" elderly volunteers was investigated with computed tomographic scans, psychometric testing (Extended Scale for Dementia [ESD]) and neurologic examination. Computed tomographic scans were evaluated for the presence or absence of white matter lucencies, termed leuko-araiosis. These are defined as patchy or diffuse areas of decreased attenuation involving only white matter and with no change in adjacent ventricles or sulci. The nine controls with leuko-araiosis had lower scores on the ESD than the 96 controls without leuko-araiosis (mean ESD with leuko-araiosis, 227.1 +/- 14; without leuko-araiosis, 237.1 +/- 8), and the difference remains significant even after adjusting for the possible confounding effects of age, sex, education, and infarct detected on computed tomography. Significant differences were also found comparing subjects with leuko-araiosis and those without in respect to abnormal gait, limb power, plantar response, and the rooting and palmomental reflexes. Leuko-araiosis may represent a marker for early dementia. The pathophysiology of this finding remains uncertain. Our results suggest that white matter abnormalities play a role in the development of intellectual impairment in the elderly.

Aged↗
PubMed1987

Cognitive and neurologic findings in demented patients with diffuse white matter lucencies on computed tomographic scan (leuko-araiosis).

A series of patients referred to the University of Western Ontario, London, Dementia Study for investigation of possible dementia underwent computed tomographic scans, psychometric testing (Extended Scale for Dementia [ESD]), and neurologic examination. Thirty-nine of the 113 patients studied (ischemic score, less than or equal to 4) were found to have leuko-araiosis, which we have defined as patchy or diffuse lucencies in the white matter. Patients with leuko-araiosis had significantly lower mean scores on the ESD, 109.7 +/- 61.2, compared with mean scores of 148.5 +/- 78.0 in those without. However, only a trend toward lower scores on the ESD was observed when age, sex, education, and infarct were taken into account in the analysis of covariance. Leuko-araiosis was found to be associated with increasing age, hypertension, abnormalities of power in the limbs, and extensor-plantar responses in this sample of patients. In patients with Alzheimer's disease (AD) alone, diagnosed clinically, 29 out of 91 demonstrated leuko-araiosis on computed tomography, but scores on the ESD in this group overall were not significantly different when those with and without leuko-araiosis were compared. In less advanced cases, however, a highly significant trend was evident for leuko-araiosis to be associated with increased dementia in AD. The results are consistent with the hypothesis that leuko-araiosis is associated with dementia in AD, and that this is either most marked or most easily identifiable before the dementia becomes very severe.

Aged↗