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Biomedical subjects

L Russell

Publications and source records attributed to L Russell.

At least 91 records · Page 5Linked to original sources
PubMed1980

On the presence of bridges linking the inner and outer acrosomal membranes of boar spermatozoa.

The presence of structures bridging the inner and outer acrosomal membranes of the equatorial segment of boar spermatozoa was clearly demonstrated in cells that have undergone a variety of treatment procedures to displace the electron-dense contents of the acrosome. En-face sections show bridges to be punctate and not linearly extensive as might be suggested by sections perpendicular to the flat plane of the head. About 4.5 x 10(5) bridges, each measuring 7 nm across and spaced 7 nm apart, are arrayed hexagonally in the equatorial segment, but bridges are not present within the principal segment of the acrosome. Short-term treatment with trypsin partially digests the bridges, but does not disrupt the spacing or strict parallel configuration of equatorial segment membranes. However, short-term treatment with pronase digests most bridges and effectively disrupts the typical configuration of the equatorial segment. Freeze-fracture of the cytoplasmic face of the acrosomal membranes of the equatorial segment reveals a pattern throughout the phospholipid layer of the membrane which is similar to the pattern of bridges present in en-face thin sections of the equatorial segments. The data suggest that numerous bridges link the inner and outer acrosomal membranes of the equatorial segment of the acrosome and they play a major, if not an exclusive, role in maintaining the close spacing and parallel arrangement of the membranes in this portion of the acrosome.

Acrosome↗
PubMed1980

Family structure, marital adjustment, and intimacy in patients referred to a consultation-liaison service.

Patients with chronic physical symptoms of obscure etiology who are referred to a psychiatric consultation service demonstrated characteristic differences in their marital adjustment and family structure when compared with nonpatient controls. Although marital adjustment, as perceived by patient and spouse, was similar to that of nonpatient couples and an absence of overt conflict was demonstrated, the marriages of patients were characterized by specific incompatibilities in intimacy, socializing, and initiative. The family structure also demonstrated a preoccupation with relationships within the family, with resultant isolation from extrafamilial social contacts, and a lack of problem solving ability. The study suggests that the level of intimacy in a marriage may be a predisposing vulnerability risk factor and an influence on illness behavior, or a perpetuating factor in the sick role assumed by at least some hospitalized patients. Finally, the study suggests that marital assessment may have value in the evaluation of patients with chronic physical complaints of obscure etiology.

Adaptation, Psychological↗
PubMed1980

Cognitive family therapy.

Cognitive family therapy is a new short-term psychotherapy which facilitates self-disclosure. The paper defines self-disclosure and differentiates cognitive self-disclosure from self-exposure and emotional self-disclosure. The relationship of cognitive self-disclosure in facilitating marital intimacy is developed. A case history is presented which describes the therapeutic process and suggests possible future research to understand what constitutes the specific change process in Cognitive family therapy. Data from an uncontrolled outcome study involving eleven families is discussed. Results from objective self-report tests given prior to treatment and at follow-up are examined, with the outcome suggesting that cognitive family therapy merits further evaluation.

Clinical Competence↗
PubMed1980

Concepts of intimacy in the general population.

A random sample of 50 adults in the general population received an open ended interview regarding their concepts of intimacy. A second random sample of 24 couples from the general population and 24 clinical couples received a standardized interview in which concepts of intimacy were systematically rated to develop an operational definition of the dimensions of intimacy. Self-disclosure was identified as a fundamental aspect of intimacy in interpersonal relationships and marriage. Expression of affection, compatibility, cohesion, identity, and the ability to resolve conflict were also considered important aspects of intimacy. Sexual satisfaction was considered less important than previous definitions of intimacy have suggested. The perception of his or her parents' level of intimacy was thought to influence the subject's own interpersonal relationships. Couples with marital maladjustment and/or psychiatric illness were less aware of aspects of their marriage which influence intimacy. They more frequently disagreed that sexuality influenced their level of intimacy. The study suggests that self-disclosure and parental interpersonal intimacy may be fundamental factors in marital adjustment which merit further research.

Adult↗
PubMed1980

Characterization and localization of adenylyl cyclase in membrane vesicles and intact boar and human spermatozoa.

The enzymic properties of adenylyl cyclase in purified membrane vesicles from human and boar spermatozoa are described. Plasma membrane vesicles, which appear to be right-side-out, show a marked increase in activity in the presence of the detergent Triton X-100, manganous ion and alkaline pH. Electron-microscope cytochemical assays indicated the presence of adenylyl cyclase in boar and human sperm plasma membranes and also within the axoneme of intact human spermatozoa. The significance and precautions in the evaluation of the cytochemical data are discussed.

Adenylyl Cyclases↗
PubMed1979

Direct evidence for formation of hybrid vesicles by fusion of plasma and outer acrosomal membranes during the acrosome reaction in boar spermatozoa.

A variety of treatment procedures was utilized to identify the origin and composition of the vesicles formed during the acrosome reaction of boar spermatozoa. Whether the acrosome reaction occurred spontaneously or was induced chemically the vesicles were hybrid vesicles composed of roughly equal proportions of plasma and outer acrosomal membranes.

Acrosome↗
PubMed1979

Gap junctions between Sertoli and germ cells of rat seminiferous tubules.

Ultrastructural observations of rat seminiferous tubules show clearly the presence of plasma membrane junctions between Sertoli and germ cells in the basal and adluminal compartments. Results obtained from the freeze fracture and thin section techniques were correlated in order to elucidate the nature of these intercellular junctions. We suggest that these intercellular membrane specializations are gap junctions which occur within regions of plasma membrane that also exhibit adherens-like modifications.

Animals↗
PubMed1979

Morphologic characteristics of the chemically induced acrosome reaction in human spermatozoa.

The morphologic changes accompanying the acrosome reaction in human spermatozoa, as it is induced by the antibiotic A23187 and calcium ions, are described. The reaction is shown to be similar to that observed in other species when the reaction occurs spontaneously or is induced by physiologic fluids. The reaction in human spermatozoa differs from the chemically induced reaction in other species in that plasma membrane microfilaments, prominent in the boar, and tubular-like elements prominent in boar, rabbit, and monkey sperm, are not observed. Motility remains high when human spermatozoa are treated with A23187 and calcium and it is possible that these agents may be useful in the study of certain causes of infertility.

Acrosome↗
PubMed1978

Ultrastructural characterization of nuage in spermatocytes of the rat testis.

At least six different types of nuage, as judged by morphological appearance, were found in spermatocytes of the adult rat testis. These were characterized by form, distribution, and association with other organelles. The appearance (with time) and the dissociation of some nuage types were recorded in conjunction with other events of the spermatogenic cycle. The data indicate that all types of nuage behave in a dynamic way. Especially interesting were the findings concerning the chromatoid body. This structure was first observed in mid-pachytene spermatocytes. By late diplotene and during the first meiotic division, it had lost its prominence such that its eventual fate could not be determined. Large dense (0.5 micrometer) bodies appeared de novo in the cytoplasm of newly formed secondary spermatocytes. They were seen scattered throughout the cell and in association with mitochondria. With time these bodies appeared to coalesce to form the large definitive chromatoid of a type similar to that known to be present throughout most of the remainder of spermiogenesis.

Animals↗
PubMed1978

Isolation and characterization of membrane vesicles from human and boar spermatozoa: methods using nitrogen cavitation and ionophore induced vesiculation.

A method for isolation of plasma membrane vesicles from human and boar spermatozoa using nitrogen cavitation is described. The purity of the preparations were assessed by electron microscopy, marker enzyme assay and the sedimentation characteristics of fused plasma membrane-acrosomal membrane vesicles in sucrose gradients. PAGE-SDS profiles of plasma membrane polypeptides from boar spermatozoa were significantly different from those of human spermatozoa. Differences in electrophoretic profiles of polypeptides from different regions of the spermatozooon were also observed.

Acrosome↗
PubMed1978

The dependence of Escherichia coli asparaginase II formation on cyclic AMP and cyclic AMP receptor protein.

The amount of asparaginase II in an Escherichia coli wild-type strain (cya+, crp+) markedly increased upon a shift from aerobic to anaerobic growth. However, no such increase occurred in a mutant (cya) lacking cyclic AMP synthesis unless supplemented with exogenous cyclic AMP. Since a mutant (crp) deficient in cyclic AMP receptor protein also did not support the anaerobic formation of this enzyme, it is concluded that the formation of E. coli asparaginase II depends on both cyclic AMP and cyclic AMP receptor protein.

Aerobiosis↗
PubMed1978

Characterization of rat spermatocytes after plastic embedding.

Rat testicular tissue, perfused with glutaraldehyde, post-fixed with osmium and stained with toluidine blue, was studied to obtain information which could be used to characterize spermatocytes (also type B gonia and Step 1 spermatids) with the light microscope. Measurements of relative cell, nuclear sizes and absolute nuclear size are presented in graphic form, demonstrating the progressive growth found for spermatocytes. Early prophase spermatocytes (preleptotene, leptotene, zygotene) gradually increased in size. Pachytene cells showed no growth until Stage IV, at which point a dramatic size increase began and continued until the diplotene phase. Guidelines to identify a particular phase of meiosis were established for spermatocytes using primarily nuclear traits. Examination of longitudinal sections through Stages XIII, XIV and I were useful for comparing cells from Meiotic divisions (meta-, ana-, and telophases) I and II and also for differentiating secondary spermatocytes from Step 1 spermatids.

Animals↗
PubMed1977

Desmosome-like junctions between Sertoli and germ cells in the rat testis.

Desosome-like junctions between Sertoli cells and germ cells (spermatogonia, spermatocytes and non-elongate spermatids) were observed in the adult rat testis. At all levels, certain features were characteristic of this relationship, the most prominent being a densification of the subsurface aspect of the plasma membranes of each cell. The Sertoli cell counterpart demonstrated an abundance of cytoplasmic fibrils which converged on the density, but no such feature was evident in the germ cell counterpart. The width of the intercellular space was variable, ranging in some regions from approximately 3-5 nm, to other regions of approximately 14-18 nm, the latter being representative of most areas of contact. A poorly represented, and often discontinuous, intermediate dense line was observed in the intercellular space. Hypertonic fixative solutions containg dextrose were utilized to provoke tissue shrinkage and exaggeration of the intercellular space within the basal compartment of the testis. Cell separation was evident over most regions of the cells, except where desmosome-like contacts were present. Forces transmitted from one cell to another at desmosome-like contacts resulted in tearing of cellular fragments, while junctional regions of both cells remained intact. These observations indicate that desmosome-like junctions are strong adhesive sites between germ cells and Sertoli cells.

Animals↗
PubMed1977

Movement of spermatocytes from the basal to the adluminal compartment of the rat testis.

The progressive movement of primary spermatocytes from the basal to the adluminal compartment of the seminiferous tubule was studied after testes were fixed with standard and hypertonic solutions. In stages VI, VII and VIII of the cycle (classification of Leblond and Clermont, '52), preleptotene spermatocytes were observed within the basal compartment of the seminiferous tubule. Resting on the basal lamina, these cells were bound tightly to neighboring Sertoli cells by desmosome-like junctions. In late stage VIII and early stage IX, basal processes of Sertoli cells were observed between the newly formed leptotene cells and the basal lamina, and in stage IX, the Sertoli processes met to form a junction of the zonula adherens type. This junction formed a permeability barrier which restricted the free access of fixative into the spaces around leptotene cells. Evidence for this was found in the absence of the shrinkage artifact produced with hypertonic solutions in earlier stages. In longitudinal sections, the permeability barrier was first observed in an area of the tubule in which sperm release was also taking place. In mid-stage IX and in stage X, sertoli-Sertoli junctional specializations formed de novo below the leptotene spermatocyte, while those from the preceding stages, present above the leptotene spermatocytes, remained intact. Thus, tight junctions were in evidence for a considerable period of the time, both above and below the leptotene spermatocytes. At no time in the process of germ cell movement toward the lumen did these cells exhibit evidence of amoeboid movement or lose desmosome-like contacts with the surrounding Sertoli cells. From this study it is concluded that the Sertoli cells play an active role in the transfer of spermatocytes to the adluminal compartment. A transient intermediate compartment of the seminiferous tubule is described, one which allows for the continual maintenance of the blood-testis barrier during transit of spermatocytes from the basal to the adluminal compartment.

Animals↗