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Biomedical subjects

L Ross

Publications and source records attributed to L Ross.

At least 55 records · Page 3Linked to original sources
PubMed1996

Identification of pesticide poisoning in wildlife.

The Wildlife Incident Investigation Scheme investigates incidents of suspected poisoning of wildlife (also honey bees and companion animals) by pesticides in the United Kingdom. The approach to these investigations has evolved over the past 30 years. Field investigations, post-mortem examinations, toxicological data and experience of previous poisoning incidents assist in the selection and interpretation of appropriate chemical analyses. Several 'multi-residue' and several 'individual compound' analytical methods for pesticides in wildlife are currently in use; these are described.

Animals↗
PubMed1996

Meiotic recombination initiated by a double-strand break in rad50 delta yeast cells otherwise unable to initiate meiotic recombination.

Meiotic recombination in Saccharomyces cerevisiae is initiated by double- strand breaks (DSBs). We have developed a system to compare the properties of meiotic DSBs with those created by the site-specific HO endonuclease. HO endonuclease was expressed under the control of the meiotic-specific SPO13 promoter, creating a DSB at a single site on one of yeast's 16 chromosomes. In Rad+ strains the times of appearance of the HO-induced DSBs and of subsequent recombinants are coincident with those induced by normal meiotic DSBs. Physical monitoring of DNA showed that SPO13: : HO induced gene conversions both in Rad+ and in rad50 delta cells that cannot initiate normal meiotic DSBs. We find that the RAD50 gene is important, but not essential, for recombination even after a DSB has been created in a meiotic cell. In rad50 delta cells, some DSBs are not repaired until a broken chromosome has been packaged into a spore and is subsequently germinated. This suggests that a broken chromosome does not signal an arrest of progression through meiosis. The recombination defect in rad50 delta diploids is not, however, meiotic specific, as mitotic rad50 diploids, experiencing an HO-induced DSB, exhibit similar departures from wild-type recombination.

DNA, Fungal↗
PubMed1996

The value of skin testing in patients with chronic rhinitis.

The value of skin prick testing in the management of patients with chronic rhinitis has still to be established. The aim of the study was to determine how accurately atopic status could be predicted from the clinical history of allergy. We carried out a prospective audit of 103 patients undergoing skin tests in three ORL departments over a three-month period. Of 73 patients with a history of allergy or an atopic family history, 44 (60%) had a positive skin test. Twenty-one out of 30 (70%) with no history had a negative skin test. In subjects where a negative atopic history to inhaled allergens is combined with a negative family history, the incidence of negative skin test results was 79%. Skin prick testing is of questionable clinical value in the absence of positive atopic feature in the personal or family history of the patient.

Chronic Disease↗
PubMed1996

The effect of HA, TCP and ALCAP bioceramic capsules on the viability of human monocyte and monocyte derived macrophages.

The relationship between various bioceramics used in surgical implantation and inflammatory cellular response has not been fully elucidated. The objective of this study was to investigate the effect of various biomedical ceramics such as tricalcium phosphate (TCP), hydroxyapatite (HA), and aluminum-calcium-phosphorous oxide (ALCAP) on the adherence and viability of human monocyte and monocyte derived macrophages in vitro. The monocytes were isolated from human peripheral blood and seeded at a density of 5 x 10(5) cells/well according to standard laboratory procedures. Cells were considered macrophages after remaining in culture for 24 hours. Cells were then plated in each microtiter well loaded with ceramic capsules (HA, TCP and ALCAP) and buffered control. At the end of 1, 2, 3, and 7 days the viability and cell number of monocyte or monocyte derived macrophages were determined using an established assay. Cell number was determined in control wells with known amounts of cell number, a standard curve was generated by plotting absorbance units versus cell number. Biochemical analysis was performed on the aliquots obtained from the experimental and control wells at the end of each phase of the investigation. The data from this experiment suggest that: (I) monocytes and macrophages are capable of adhering to the surface of HA, TCP and ALCAP in an in vitro environment for over a 7 day period. (II) Long term incubation of ceramic capsules with macrophages revealed that the cells experienced gradual disassociation phenomenon with a greater number of cell detachment seen in the ALCAP contained wells. (III) SEM analysis of representative capsules demonstrated that there is an increase in the number of micropores on the surface of the materials after contacting a cellular environment. This observation suggest that the material surface has been modified (TCP > HA = ALCAP). (IV) Biochemical analysis of aliquots at the end of each phase showed a significant change (P < 0.05) in the activity of catalase and superoxide dismutase (SOD). Information obtained from this study provided new insights on the interrelationship between bioceramics and the possible cell response during chronic inflammation at the site of implantation.

Aluminum Oxide↗
PubMed1995

Psychometric characteristics of revised Sociotropy and Autonomy Scales in college students.

Beck, Epstein, Harrison and Emery (unpublished manuscript, 1983) developed the Sociotropy-Autonomy Scale (SAS) to assess personality constructs that were considered possible vulnerability factors to reactive depression. Principal components and factor analyses of an expanded 93-item version of the SAS were performed with successive samples of undergraduates totalling 2041 Ss. Only 59 items were needed to establish the generalizabilities of one dimension of Sociotropy and two dimensions of Autonomy. Three subscales reflecting Sociotropy, Solitude and Independence were constructed from these items. The convergent and discriminant validities of the three subscales were assessed with respect to a variety of other psychological tests. The overall pattern of relationships indicated that Solitude was positively correlated with dysphoria, perfectionism, self-criticalness, and loneliness. In contrast, Independence was positively correlated with perfectionism and self-efficacy, but inversely related to concern about approval from others. Sociotropy was correlated with dependency, self criticalness, and affiliation motivation. The findings supported the construct validity of the three revised SAS subscales.

Adjustment Disorders↗
PubMed1995

The spiritual dimension: its importance to patients' health, well-being and quality of life and its implications for nursing practice.

The spiritual dimension is described and is interpreted as the need for: meaning, purpose and fulfillment in life; hope/will to live; belief and faith. As the spiritual dimension is important for the attainment of an overall sense of health, well-being and quality of life (referred to as the health potential) and as illness and hospitalisation can precipitate spiritual distress, patients' spiritual needs should be addressed. The nurse's role in spiritual care is discussed with reference to the nursing literature.

Adaptation, Psychological↗
PubMed1995

Dexamethasone therapy for children with bacterial meningitis. Meningitis Study Group.

OBJECTIVE: To determine whether treatment with dexamethasone and ceftriaxone for children with bacterial meningitis reduces the frequency of either sensorineural hearing loss or other neurologic sequelae. DESIGN: This was a prospective, multicentered, placebo-controlled clinical trial. Subjects were followed for 1 year. SETTING: The study was conducted in six children's hospitals located in Pittsburgh, Houston, Los Angeles, Chicago, Washington, D.C., and Columbus, Ohio. PATIENTS: Enrolled were 173 children, 8 weeks to 12 years of age, with suspected bacterial meningitis; 143 children were evaluable. Eighty-seven percent of patients were followed for at least 6 weeks to 3 months, and 67% were followed for 1 year. INTERVENTIONS: Subjects were randomized to receive ceftriaxone with or without dexamethasone (0.15 mg/kg every 6 hours for 4 days). Auditory brainstem responses (ABR) were measured within 24 hours of admission. MAIN OUTCOME MEASURES: Hearing, development, and neurologic sequelae were assessed at the time of discharge and 6 weeks and 1 year later. MAIN RESULTS: One hundred forty-three patients (69 received dexamethasone and 74 received placebo) with bacterial meningitis were evaluable: Haemophilus influenzae type b (83), Streptococcus pneumoniae (33), Neisseria meningitidis (24), and three others. Overall, there was no significant difference in auditory outcome between dexamethasone and placebo recipients. Twenty-two children had bilateral moderate or more severe hearing loss at the time of the first ABR. At follow-up, the resolution of hearing impairment was nearly identical for each group. Nine of ten children who remained persistently deaf were deaf at the time of the first ABR. There were no differences in neurologic or developmental outcome between groups. CONCLUSION: All but one child with persistent bilateral moderate or more severe hearing loss had demonstrable deafness at the time of the first ABR. Dexamethasone did not significantly improve audiologic, neurologic, or developmental outcome in children with bacterial meningitis.

Ceftriaxone↗
PubMed1994

A truncated recombinant intercellular adhesion molecule-1 inhibits adhesion of leukemic cell lines to upregulated endothelial cells.

Intercellular adhesion molecule-1, a member of the immunoglobulin supergene family, is the ligand for the integrin lymphocyte function associated antigen-1. Intercellular adhesion molecule-1 and lymphocyte function associated antigen-1 binding interactions mediate leukocyte adherence and migration. Previous work has shown that the adherence of lymphocyte function associated antigen-1 is directed to the first immunoglobulinlike domain of the endothelial cell surface protein intracellular adhesion molecule-1. We have constructed a truncated intercellular adhesion molecule-1 gene encoding the first 185 amino acids from the amino terminus and overexpressed it in Escherichia coli. The recombinant protein was purified from insoluble inclusion bodies and refolded into an active conformation by a denaturation/renaturation cycle. The identity of the protein was confirmed by microsequencing and by Western blot analysis using a polyclonal antibody to ICAM-1. We have demonstrated that this soluble region of the otherwise membrane-bound ligand is an inhibitor of Molt or HL-60 cell adhesion to cytokine-stimulated endothelial cells.

Amino Acid Sequence↗
PubMed1994

Prevalence of sperm bound antibodies in infertile men with varicocele: the effect of varicocele ligation on antibody levels and semen response.

An increased level of antisperm antibodies has been demonstrated in infertile men with varicocele compared with normal fertile men, suggesting a possible cause and effect relationship. To evaluate the possible etiological role of antisperm antibodies in varicocele patients, we performed a prospective study of 32 infertile men undergoing varicocele ligation. Semen analyses and antisperm antibodies as measured by the immunobead test were performed preoperatively and postoperatively at 3 and 6 months. Of the infertile men with varicocele 28% had a positive immunobead test compared with 0% of normal fertile men. The average total motile sperm count was significantly different (p < 0.05, 2-tailed t test) for 9 varicocele patients with sperm-bound antibody (3.2 x 10(6)) compared with 23 without antibody (8.4 x 10(6)). Postoperatively, 68% of all patients exhibited improved semen parameters, with no change in antibody status in either group. Among the antibody positive group 71% showed an increase in motile sperm per ml. of 2.8 x 10(6) to 17.2 x 10(6) (525% increase, p < 0.05), while in the antibody negative group 67% showed an increase of 3.8 x 10(6) to 24.9 x 10(6) (553% increase, p < 0.05). Our study suggests that there is an increased incidence of sperm-bound immunoglobulin in infertile varicocele patients and an apparent adverse effect on semen parameters in these patients. However, the presence of sperm-bound immunoglobulin did not affect the percentage response to surgical correction, nor can we postulate an immunological mechanism as a major etiological factor in varicocele induced infertility.

Adult↗
PubMed1994

Measuring the functional impact of fatigue: initial validation of the fatigue impact scale.

The fatigue impact scale (FIS) was developed to improve our understanding of the effects of fatigue on quality of life. The FIS examines patients' perceptions of the functional limitations that fatigue has caused over the past month. FIS items reflect perceived impact on cognitive, physical, and psychosocial functioning. This study compared 145 patients referred for investigation of chronic fatigue (ChF) with 105 patients with multiple sclerosis (MS) and 34 patients with mild hypertension (HT). Internal consistency for the FIS and its three subscales was > .87 for all analyses. Fatigue impact was highest for the ChF group although the MS group's reported fatigue also exceeded that of the HT group. Discriminant function analysis correctly classified 80.0% of the ChF group and 78.1% of the MS group when these groups were compared. This initial validation study indicates that the FIS has considerable merit as a measure of patient's attribution of functional limitations to symptoms of fatigue.

Adult↗
PubMed1994

Depressive disorders and suicidal intent in adolescent suicide attempters.

This study describes the relationships between the presence of a depressive disorder, suicidal intent, and the medical seriousness of a suicide attempt in an adolescent sample. Consecutive adolescents who attempted suicide were evaluated for the presence or absence of current DSM-III-R depressive disorders (DD). Adolescent suicide attempters with DD were compared with those without DD regarding the level of their suicide intent and the medical seriousness of their suicide attempt. Adolescent suicide attempters with a diagnosis of DD were found to have a higher level of suicidal intent than were those without depressive illness. There was no relationship between the medical seriousness of the suicide attempt and the presence of DD. Clinicians should specifically assess for DSM-III-R DD as a means of determining suicidal intent in adolescent suicide attempters.

Adolescent↗
PubMed1993

Transoral surgery: an anatomic study.

The transoral approaches have become commonplace in modern neurosurgical practice for treatment of ventral midline lesions of the clivus and upper cervical spine. Although the standard technique of transoral surgery is conceptually simple, anatomic relationships are not so readily appreciated. The present study was undertaken in an effort to define more clearly the midline anatomic relationships as they pertain to the standard transoral and transpalatine operations. The anatomic relationships involved in planning microsurgical transoral approaches were examined in 15 human cadavers. Landmarks approximating the midline of the skull base and the upper cervical spinal canal were defined to assist the surgeon's orientation. Measurements were made in axial, sagital, and parasagittal planes to various neurovascular structures in the posterior cranial fossa and upper cervical spinal canal. The study revealed that, for the standard transoral and transoral-transpalatine dissections, the carotid arteries, abducens nerves, interior petrosal sinuses, hypoglossal nerves, and vertebral arteries would be a greatest risk being 0.76, 1.06, 1.51, 1.34, and 1.52 cm from the midline at specified locations. The measurements and the computed tomography images provide a useful reference for the surgeon.

Journal Article↗