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Biomedical subjects

A Williams

Publications and source records attributed to A Williams.

At least 361 records · Page 20Linked to original sources
PubMed1995

Stathmin is expressed by the proliferating hepatocytes during liver regeneration.

Aim-To determine the liver cell populations that express the phylogenetically conserved cytosolic protein stathmin during liver regeneration.Methods-Double immunostaining for stathmin and the Ki67 antigen was performed on sections of formaldehyde fixed, paraffin wax embedded tissues from 31 liver specimens. These included a variety of disease conditions characterised by some degree of hepatocyte regeneration. Quantitative western blot analysis was performed on 22 of these specimens.Results-Variable amounts of stathmin protein were detected by western blotting in all of the specimens examined. Stathmin was not detected in three cases of histologically normal liver. On immunostaining, stathmin was demonstrated in a proportion of hepatocytes as well as lymphoid inflammatory cells and other tissue elements. In all cases most of these stathmin positive cells showed nuclear positivity for the Ki67 antigen.Conclusions-Stathmin is expressed by proliferating hepatocytes but not by resting hepatocytes. Thus, it is likely that the protein has a function important to cell proliferation as opposed to cell differentiation.

Journal Article↗
PubMed1995

Epidural anaesthesia and urinary dysfunction: the risks in total hip replacement.

Epidural anaesthesia in total hip replacement is an established and safe practice. It may be used alone or in combination with general anaesthesia for analgesia. Urethral catheterization in the perioperative period is known to greatly increase the complication of deep sepsis following total hip replacement. We assessed the effect on the incidence of urinary catheterization of using bupivocaine epidural anaesthesia in addition to general anaesthesia in total hip replacement. A prospective study was made of 113 total hip replacements. The incidence of catheterization in male patients who received an epidural was 67% compared to only 12% who had no epidural [P = 0.001]. In women the corresponding rates were 30% and 23%. We conclude that in men the use of supplementary epidural anaesthesia with bupivocaine is associated with a worrying increased need for urinary catheterization. This must be balanced against the claimed benefits of this form of anaesthesia.

Adult↗
PubMed1995

Compliance with the 1992 California motorcycle helmet use law.

To evaluate helmet use in California before and after the introduction of an unrestricted helmet use law on January 1, 1992, observations of motorcycles and their riders were made at 60 locations in seven California counties, twice before and four times after the law was introduced. Helmet use increased from about 50% in 1991 to more than 99% throughout 1992. Compliance was achieved despite variations in helmet use by motorcycle design and road type. Seven percent of riders used nonstandard helmets after the law. With adequate enforcement, unrestricted helmet use laws can achieve almost 100% compliance and reduce the number of people riding motorcycles.

California↗
PubMed1995

Characteristics of rabbit muscle adenylate kinase inhibition by sulfur and recovery by dithiothreitol.

Structure-function relationships of rabbit muscle adenylate kinase (RMAK) were studied by examining the characteristics of inhibitions by hydrophobic inhibitors and reactivations by sulfhydryl reagents. RMAK is inhibited by 1-butanol,N-ethylmaleimide (NEM) and elemental sulfur (S8) with increasing effectiveness in the order of increasing hydrophobicity. Characteristics of these hydrophobic inhibitors are compared with inhibitors forming covalent bonds or reversible complexes. A mechanism is proposed for hydrophobic inhibitors of RMAK that involves conformational changes promoted by interacting with hydrophobic regions. The reversal of RMAK inhibition by sulfhydryl compounds involves a conformational change that exposes hydrophobic regions and the inhibitor to water. Circular dichroism (CD) data show changes in the secondary structures of RMAK, indicating that the inhibitors and the sulfhydryl compounds promote conformational changes. The results of these studies show that the activity of a small enzyme can be controlled in a manner analogous to the allosteric control of larger enzymes.

Adenosine Triphosphate↗
PubMed1995

Stathmin expression is a feature of proliferating cells of most, if not all, cell lineages.

BACKGROUND: Stathmin is a phylogenetically conserved protein which was identified initially as a prominent cytosolic protein in hemopoietic cells, endocrine cells, brain, and testis. In these tissues, it has been suggested that the level of stathmin expression is important in development and cell proliferation. Furthermore, stathmin phosphorylation appears to be involved in the regulation of cell growth arrest, terminal differentiation, and hormone secretion. Elevated levels of expression of stathmin have been described in leukemia and lymphoma cells. The aim of this study was to characterize the distribution of cells that express the stathmin protein in a wide variety of normal human and rodent tissues. EXPERIMENTAL DESIGN: First, antisera against a synthetic stathmin peptide have been raised in rabbits and the specificity of these antisera confirmed by their reactivity with stathmin on 1-dimensional and 2-dimensional Western blots. Second, the most appropriate means of fixing tissues in order to stain stathmin has been investigated. Finally, using the optimized conditions of tissue fixation, the antisera have been used to immunostain sections taken from a wide variety of tissues. RESULTS: Immunopositivity was found in cells of all the lineages studied, with the stained cells present within the proliferating compartment of tissues. Conversely, most nonproliferating mature cells did not stain with the antisera to stathmin. The only nonproliferating cells that appeared to express stathmin were a subpopulation of glial cells, neurons, and anterior pituitary cells. CONCLUSIONS: It is proposed that stathmin is necessary for cell proliferation in most, or all, cell lineages and that its primary function relates to some aspect of cell division.

Animals↗
PubMed1995

Determinations of dangerousness in forensic patients: an archival study.

The involvement of mental health professionals in determinations of dangerousness is both common and controversial. Among the various contexts for these evaluations, the release of potentially violent forensic patients from maximum security facilities evokes justified concern from involved experts and apprehension to outrage from the immediate community. We sought to examine how conclusions are reached on dangerousness at two sequential stages: clinical recommendations and Manifest Dangerousness Hearings decisions. In an archival study of 245 patients, we found that lack of progress in the institution and physical assaultiveness were the strongest correlates with dangerousness. In contrast, experts and review boards appeared to be relatively less influenced by diagnosis, types of treatment, and sociodemographic variables.

Adult↗
PubMed1994

The effect of the 1992 California motorcycle helmet use law on motorcycle crash fatalities and injuries.

OBJECTIVE: To determine the effects of the California motorcycle helmet use law on statewide fatalities and a large sample of nonfatal injuries before and after law implementation. DESIGN: Police reports and death certificates were collected for motorcycle crash fatalities in California for 1991 (prelaw) and 1992 (postlaw). Official counts of registered motorcycles provided a statewide basis for exposure to a motorcycle crash. Autopsy results were collected for fatalities in 11 counties. Hospital records were reviewed for nonfatal injuries in 28 hospitals in 10 of the 11 counties. Police reports were linked to injury data for the riders. SUBJECTS AND PATIENTS: A total of 850 fatalities and injury data for 547 fatally injured riders and 3252 nonfatally injured patients. MAIN OUTCOME MEASURES: Changes in number and rates among statewide fatalities were estimated. The number and pattern of head injuries in fatally and nonfatally injured motorcycle riders were evaluated. RESULTS: After implementation of the helmet use law, statewide motorcycle crash fatalities decreased by 37.5%, from 523 fatalities in 1991 to 327 in 1992, more than 37%, and an estimated 92 to 122 fatalities were prevented. Motorcycle fatality rates were reduced by 26.5%, from 70.1 per 100,000 registered motorcycles in 1991 to 51.5 per 100,000 in 1992. Head injuries decreased significantly among both fatally and nonfatally injured motorcyclists. CONCLUSION: Enactment of an unrestricted helmet law significantly reduces the incidence of motorcycle crash fatalities and the number and severity of head injuries.

Accidents, Traffic↗
PubMed1994

Epstein-Barr virus in inflammatory diseases of the liver and liver allografts: an in situ hybridization study.

The Epstein-Barr virus is associated with a broad spectrum of lymphoproliferative diseases in liver allograft recipients. To investigate the effects of primary infection in children following liver transplantation and the possible role of Epstein-Barr virus in the pathogenesis of unexplained chronic hepatitis after transplantation, we used an in situ hybridization technique to detect small virus encoded nuclear RNAs in posttransplant specimens. For comparison, other posttransplant complications and diseases occurring in the nontransplanted liver were studied with the same method. We examined 114 specimens in the following categories: (a) children with primary Epstein-Barr virus infection after transplant (n = 25), (b) chronic hepatitis more than 12 mo after transplant (n = 14), (c) rejection (n = 15), (d) normal/near-normal histology more than 12 mo after transplant (n = 13) (e) end-stage acute liver disease (n = 9) and (f) end-stage cirrhosis (n = 38). Thirty-three of 114 specimens had labeling of occasional portal and parenchymal lymphoid cells. These were present in each of the six main diagnostic categories listed above: 2 of 25, pediatric; 6 of 14, chronic hepatitis; 4 of 15, rejection; 1 of 13, normal; 4 of 9, acute; and 16 of 38, cirrhosis. In none of the patients with Epstein-Barr virus-infected cells did lymphoproliferative disease subsequently develop. In conclusion, we have been unable to show an obvious association between Epstein-Barr virus infection and graft dysfunction after liver transplantation. Our results suggest that immunological response to primary infection in children after liver transplantation may be adequate.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1994

Is abnormal retinal development in albinism only a mammalian problem? Normality of a hypopigmented avian retina.

The central retina in hypopigmented mammals is underdeveloped. In the outer retina this deficit is confined to rods. Also, many ganglion cells in temporal regions project inappropriately to the contralateral hemisphere. This study addresses the question of whether pigment-related abnormalities occur in the central retina of a non-mammal, the bird. Birds have a highly developed central retina, but unlike most mammals they do not have a significant uncrossed retinal projection. Consequently, examination of the retinae of hypopigmented birds will reveal whether there is a relationship between the two abnormalities. Also if one of the primary effects of albinism is centred on rods, then albino birds may not show a deficit, because their retinae are cone dominated. Retinae from normally pigmented and two forms of hypopigmented budgerigars (Melopsittacus undulatus) were studied. Measurements of layer thickness, cell density and cell size were made at a range of locations in the ganglion cell layer and in the inner and the outer nuclear layers. Estimates of cone numbers were also made. Each strain of bird had an area of increased retinal layer thickness in dorso-temporal regions, but not a fovea. Although there were variations in the measurements undertaken between the strains, none were pigment related or consistent with the abnormality found in the central retina in albino mammals. Consequently, the underdevelopment of the central retina seen in hypopigmented mammals does not occur in this bird. There are two possible explanations for this result. First, normal mammalian retinal development may depend partly on time-dependent interactions in the maturation of the retinal pigment epithelium and the neural retina. Although there is a common time table for the development of the mammalian visual system when expressed in terms of the caecal period, which is between conception and eye opening, the pace of retinal development in birds is accelerated, which may alter interactions between these regions. Second, as the bird retina is cone dominated, any deficits in albino strains may be relatively minor.

Albinism↗
PubMed1994

Comparative inhibition patterns of adenylate kinases from mammals, bird, fish and microorganisms.

The S8 inhibitions of AKs from six different sources were studied in mammals, birds, fish, and a microorganism. All AKs tested were inhibited by S8. Except for carp, all inhibited AKs from those tested were reactivated by DTT. Inhibitions of AKs by other hydrophobic inhibitors, NEM, butanol and ethanol were also studied. The inhibitions by S8 suggest that the hydrophobic pockets in the AKs cover a wide phylogenetic range. All inhibitions by S8 are reactivated by DTT. Unlike the inhibitions by S8, the characteristics of inhibitions by the other hydrophobic inhibitors differed among the AK sources tested and none was the irreversible type. The data suggest that no covalent bonds were formed with NEM. Similarly, the ability to reactivate the inhibitions by DTT differed among the AK sources. The possibility that the hydrophobic domains in the AKs may serve as part of an enzyme activity control mechanism is discussed.

Adenylate Kinase↗
PubMed1994

Living with diabetes: issues for nursing practice.

Discussion in this paper is based on findings drawn from research undertaken within a qualitative framework of analysis, and with the purpose of exploring people's perceptions of living with diabetes, including the nursing care they receive. A major theoretical concern is to demonstrate the importance of placing patients' and clients' experiences at the centre of nursing interest and practice. It is argued that understanding a disease process should of necessity include an understanding of the concerns of those who live with it. Findings related to the following research questions are discussed: first, what are the challenges of living with diabetes? and second, what are people's perceptions of the nursing care they receive?

Adaptation, Psychological↗
PubMed1994

What bothers caregivers of stroke victims?

Caregivers of brain-impaired persons report that the caregiving experience often is stressful to them. The caregiving stress model has been based primarily on stress associated with caring for persons with Alzheimer's disease. Relatively little information is available on stressors for caregivers of stroke victims, however, who could be expected to have different stressors based on the different underlying pathology. Caregivers of persons with stroke therefore were asked to respond to the Brain Impairment Behavior Inventory (BIBI) and the companion Brain Impairment Behavior Bother Scale (BIBBS) and to list the three most important stressors for them. The behaviors of the persons with stroke which were most stressful for this sample of caregivers were irritability, dependence with resulting caregiver confinement and immature behavior. Nursing interventions targeted toward alleviating the stress caused by these behaviors could include investigation of treatable causes of brain dysfunction, a search for triggers for irritability and bad temper, and use of community-based support systems such as stroke clubs.

Adult↗
PubMed1994

Microwave oven antigen retrieval applied to the immunostaining of cytopathology specimens.

Microwave oven antigen retrieval has been developed to extend the range of antibodies that can be used upon sections of fixed and processed tissue. It has the additional advantages of improving immunostain intensity and reducing background positivity. It can also be employed as an alternative to proteolytic digestion. In this study the effects of microwave oven heating upon immunochemical staining of cytopathological specimens with a range of selected antibodies have been investigated. Microwaving did not result in loss of cells, and there was no need to use adhesive-coated slides. The method improved the staining intensity and reduced background with antibodies against a variety of antigens that are difficult or impossible to detect in formaldehyde-fixed cytological material. Microwave heating was also used successfully as an alternative to trypsin digestion, and had the advantage of reduced morphological distortion. The technique was useful in demonstrating the soluble formalin-sensitive antigen p19 on cytospins fixed in formaldehyde vapour. Microwave oven heating thus shows promise of extending the scope of immunostaining in clinical cytopathology.

Antigens↗