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Biomedical subjects

L Leach

Publications and source records attributed to L Leach.

32 records · Page 2Linked to original sources
PubMed1990

Cytomegalovirus infection in women attending a sexually transmitted disease clinic.

To evaluate prospectively the relationship between current and past sexual practices and seroprevalence of cytomegalovirus (CMV) in adult women, 1481 women (1101 white, 301 black, 79 other) attending a sexually transmitted disease clinic underwent a standardized interview and genital examination. CMV seroprevalence was higher in black (78%) than in white (59%) women. In logistic regression models that adjusted for age and years of education, CMV seropositivity in white women was associated with younger sexual debut (P = .001), more lifetime sex partners (P = .025), recent new partner(s) (P = .003), and parity (P = .002), and was inversely associated with use of barrier contraception (P = .006). In black women, after adjustment for demographic characteristics, CMV antibody was associated with greater numbers of recent sex partners (P = .007), new sex partners (P = .04), and with cervical infection with Chlamydia trachomatis (P = .05). This study confirms that sexual activity is an important determinant of CMV infection in both white and black women; however, the relative contributions of sexual and nonsexual transmission of CMV apparently vary and require further investigation.

Adolescent↗
PubMed1989

Immunogold localisation of endogenous immunoglobulin-G in ultrathin frozen sections of the human placenta.

Endogenous immunoglobulin-G was localised in ultrathin frozen sections of human term placenta by use of an indirect immuno electron-histochemical methodology. Immunoreactivity of endogenous IgG to rabbit anti-human immunoglobulin-G antibody was visualised by use of protein-A--colloidal gold complex. Gold marked the syncytiotrophoblast in both coated and uncoated regions of the apical plasmalemma, in vesicles and multivesicular bodies, and in vesicles near the basal plasmalemma. Immunoreactivity was also seen in the interstitial space between the trophoblast and the fetal endothelial layer as well as in various types of vesicles within the endothelial cells. No immunoreactivity was seen in the intercellular clefts of the endothelium. The pattern of localisation observed is consistent with receptor-mediated uptake of immunoglobulin-G into the syncytiotrophoblast of the human placenta followed by release into the interstitial space and then vesicular transport through the endothelium.

Female↗
PubMed1988

Cognitive deficits in olivopontocerebellar atrophy: implications for the cholinergic hypothesis of Alzheimer's dementia.

A cerebral cortical cholinergic reduction in dominantly inherited olivopontocerebellar atrophy (OPCA) was recently described. Although the magnitude of the cholinergic reduction was similar to that observed in Alzheimer's disease (AD), none of the OPCA patients was reported to have been demented. We now describe a comprehensive neuropsychological assessment of 11 patients from one of the OPCA pedigrees which we examined biochemically. Detailed neuropsychological testing disclosed previously unrecognized deficits in verbal and nonverbal intelligence, memory, and frontal system function which were positively correlated with the severity of cerebellar ataxia. However, our OPCA patients appeared to be at most only mildly disabled by their cognitive impairment and scored within or close to the normal range on a simple mental status screening examination. This, as well as an absence of any aphasia, apraxia, or agnosia, contrasts with the profile and severity observed in advanced AD dementia, characterized by a similar cortical cholinergic deficit. This finding also suggests that cholinergic reduction may explain only part of the pathophysiology underlying the dementia of AD.

Adult↗
PubMed1988

Immunoblot analysis of the humoral immune response in primary cytomegalovirus infection.

Cytomegalovirus is a common infection in immunologically normal adults. It may cause an asymptomatic infection or may manifest symptomatically as heterophilic-negative mononucleosis. Studies of CMV infection in immunocompromised patients indicate that humoral immune response plays a role in modulating disease severity; however, the effect of antibodies to CMV in modifying disease expression and transmission in immunologically normal individuals has not been well characterized. Using immunoblot technology, we have demonstrated that immune serum from normal adults contains antibodies to at least 15 CMV-associated proteins and that there is strain-to-strain variation in the expression of these immunogens. The kinetics of the immune response were evaluated by using serial sera collected from normal adults after primary CMV infection; analysis of immunoblots of these sera identified one group of antibodies to CMV proteins that arise early and are stable over time, a second group that appear late after infection, and a third group that are variable among patients and over time.

Adult↗
PubMed1987

Immunocytochemical localization of neurosecretory amines and peptides in the free-living nematode, Goodeyus ulmi.

Mammalian antibodies to the neuroamines, serotonin and gamma-amino-butyric acid (GABA) and to the neuropeptides, adrenocorticotrophic hormone (ACTH) and FMRF-amide evoked a response to Goodeyus ulmi, a free-living nematode. Serotonin-like immunoreactivity was found in cell bodies in the nerve ring and in the ventral nerve cord in all developmental stages. Neurons in the vulva, implicated in egg-laying, were immunoreactive to anti-serotonin in G. ulmi females, while in males serotonergic nerve fibres was found in the spicular region. Immunoreactivity to ACTH was also seen to differ depending on the developmental stage of G. ulmi, being present only in the ventral cord from the late L3 stage. Anti-GABA immunoreactivity was localized in two cell bodies near the amphids in all life stages and FMRF-amide immunoreactivity was seen in the nerve ring in all developmental stages. No reactivity was found with antibodies to vasointestinal peptide and somatostatin-14.

Adrenocorticotropic Hormone↗
PubMed1980

Effects of kainic acid lesions in the lateral hypothalamus on behavior and hippocampal and neocortical electroencephalographic (EEG) activity in the rat.

Electrolytic lesions of the lateral hypothalamus (LH) are known to produce severe and chronic behavioral and electrographic abnormalities. In order to assess the effects of damage to LH cells vs damage to fibers of passage in the LH, a comparison was made of the effects of electrolytic lesions and microinjections of the neurotoxin kainic acid (kainate) in the LH. Behavior and neocortical and hippocampal electroencephalographic (EEG) activity were studied before, immediately after, and for 25 days after the lesions were made. Electrolytic-lesioned rats were aphagic and adipsic, showed an absence of normal atropine-resistant EEG activity, and a release of atropine-sensitive EEG activity in the hippocampus and neocortex. Kainic acid-lesioned rats showed some similar behavioral impairments but the kainate lesions produced different EEG abnormalities, including chronic slow-wave and seizure activity in both the neocortex and hippocampus. Following extended recovery hippocampal EEG was normal despite extensive cellular loss in areas CA3 and CA4. Understanding of the differences in EEG between the electrolytic and kainate effects was compounded by widespread cellular damage in areas outside the hypothalamus in the rats with kainate lesions. Thus, the kainate-produced abnormalities precluded a simple analysis of the contribution that cell damage alone makes to LH lesion-induced behavioral and EEG changes.

Animals↗
PubMedDate not supplied

Structure and permeability of human placental microvasculature.

Endothelial paracellular junctions are important structures for the regulation of vascular permeability, junctional organisation being systematically related to the functional properties of the endothelium. Electron microscopic studies, immunocytochemistry, and single-passage permeability measurements have established that the placental microvessels resemble the fairly tight continuous microvessels of skeletal muscle both in structure and permeability. The endothelial paracellular clefts of these microvessels contain two distinct junctional entities which may influence permeability: the tight junction and the adherens junction. These clefts impose a substantial restriction to molecules above RMM 1000 Da and large haemproteins cannot cross the clefts. The 18 nm-wide zones of the clefts possess the transmembrane adhesion molecules PECAM-1 and VE-cadherin, which have been implicated in junctional assembly and permeability. Inflammatory mediators such as histamine and tumour necrosis factor cause a redistribution of these adhesion molecules to non-junctional regions, and histamine (100 microM) causes a rapid and sustained rise in extraction of radio-labeled tracers. Electron microscopy has also revealed possible first indications of tight junctional disassembly. Both the endothelia of larger placental vessels and isolated placental microvascular endothelial cells express cadherins and PECAM-1 and contain an extensive F-actin cytoskeleton, which is implicated in changes of cell shape and junctional assembly/disassembly. Thus, the human placental endothelium, using perfusion techniques and in vitro experiments, offers a valuable model for vascular permeability studies.

Female↗
PubMedDate not supplied

Not trophoblast alone: a review of the contribution of the fetal microvasculature to transplacental exchange.

The fetal microcirculation of the term human placenta offers an interesting microvascular model. A perfused placenta can be used for integrated studies of vascular permeability-structure relationships. The organization of the paracellular pathway in human placental microvessels closely resembles not only that of the guinea-pig placenta, but also that seen in typical continuous non-cerebral capillaries such as those of the myocardium. This uniformity of organization has allowed the development of a model of the organization of endothelial junctional complexes that allows testable predictions about the relationship between junctional organization and microvascular permeability. The key features of this model are: (1) molecular size restriction may be determined by a fibre matrix based on cadherin arrays in the zonula adhaerens. (2) The zonula occludens (tight junction) is discontinuous and so cannot act as a molecular sieve for solutes. It may serve as a shutter that limits the proportion of the paracellular cleft available for permeation. The main implication for placental function is that the human placental microcirculation is relatively tight and is an important restriction to diffusive permeation of the maternal-fetal barrier by large molecules.

Animals↗
PubMedDate not supplied

The use of clock tests in schizophrenia.

Though clock drawing tests are well recognized as measures of cognitive function, there is little data on the performance of patients with schizophrenia. We compared 24 patients with schizophrenia to 24 healthy, age-matched controls on clock drawing, copying, and reading. Patients with schizophrenia performed significantly worse on clock drawing and copying despite the fact that the groups had similar scores on the MMSE. Worse performance was associated with higher scores on the BPRS. Clock drawing and copying may be useful for the assessment of cognition in schizophrenia, and the monitoring of cognitive changes associated with antipsychotic medication.

Adult↗
PubMedDate not supplied

Meeting the challenge of cesarean births.

This article presents a perspective aimed at helping nurses achieve family-centered cesarean births that meet the needs of health-care consumers. It begins by discussing the concept of loss as it relates to cesarean births along with the need for parents to receive support in order to achieve acceptance of the experience. Parents' needs to have control over their birthing experience are then reviewed and the choices concerning type of anesthetic and the father's presence during the cesarean delivery are discussed in some detail. The impact of the birthing experience on readiness for discharge and long-term effects are briefly discussed and finally, a list of possible choices and suggestions aimed specifically at helping nurses are also presented.

Anesthesia↗