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Biomedical subjects

N J Martin

Publications and source records attributed to N J Martin.

At least 19 recordsLinked to original sources
PubMed2000

Development of delirium: a prospective cohort study in a community hospital.

BACKGROUND: Previous research on risk of delirium in acute hospital settings identified mainly patient variables (e.g., age) that are not amenable to intervention. The purpose of this study was to develop a model for new delirium in hospitalized older patients that included process of care and social variables. METHODS: A prospective cohort study was undertaken in a community hospital in Ontario, Canada. Research participants included 156 hospitalized patients age 65+ years and without delirium on admission who were admitted to a medical or surgical unit. The measures included daily appraisal of delirium using a standardized and validated tool, and assessment of patient, process of care, and social variables. RESULTS: Delirium developed in 28 of the 156 patients (17.9%). Older age and cognitive impairment were significant patient variables. Significant process of care variables included a high number of medications administered during hospitalization, surgery, a high number of procedures during early hospitalization (e.g., x-rays, blood tests), and intensive care treatment. CONCLUSIONS: Approximately one older patient in five developed delirium after admission to a medical or surgical unit. Risks not easily amenable to intervention included age, cognitive dysfunction, surgery, and intensive care requirements. Risk factors that are potentially modifiable included number of medications and number of procedures. Future research might focus on the efficacy of such intervention to reduce new-onset delirium in acute hospital settings.

Aged↗
PubMed2000

Burden in caregivers of cognitively impaired older adults living in the community: methodological issues and determinants.

Considerable burden is reported by informal caregivers of older individuals with cognitive impairment. Significant progress in the understanding of determinants of this burden has been achieved. However, further progress could be attained if we considered important methodological issues that may have limited our understanding of caregiver burden. These issues include subgroups of care recipients and caregivers, measurement issues, research design, and statistical techniques. Fifty-three studies published between 1980 and 1997 (inclusive) that focused on caregiver burden were abstracted to determine the extent to which the methodological issues discussed above were considered. Overall, we found considerable variability among the studies surveyed. Further understanding of the caregiving process and reductions in caregiver burden will depend on the attention to methodological issues and understanding of burden across the whole caregiving career.

Aged↗
PubMed1999

Origins of accessory small ring marker chromosomes derived from chromosome 1.

Three patients with accessory small ring chromosomes derived from chromosome 1 are presented together with additional clinical details and cytogenetic analyses of a previously reported patient. Cytogenetic analysis was undertaken by FISH using a reverse painting probe generated from one of the patients by microdissection of the r(1) chromosome and with a BAC923C6 which maps to 1p12. Results indicated that patients with r(1) chromosomes consisting of 1q12 heterochromatin and short arm pericentric euchromatin which extends to at least the BAC923C6 were associated with a normal or mild phenotype. Patients with abnormal phenotypes possessed two types of rings. One patient had evidence for contiguous pericentric short arm euchromatin which extended from the centromere to beyond the BAC923C6. Two patients showed molecular cytogenetic results which were compatible with non-contiguous chromosome 1 euchromatin. The diversity of origin of r(1)s will hamper attempts to define phenotype/genotype relationships.

Abnormalities, Multiple↗
PubMed1998

Towards automatic cell identification in DIC microscopy.

A general method is proposed for constructing templates of cells in differential interference contrast (DIC) microscopy. This takes account of the optics which generate DIC images, and is applicable to both transparent and semi-transparent cells of simple and complex shapes. Then, a template matching methodology is presented, which uses fast Fourier transforms to fit templates of a range of sizes and orientations to images. For illustration, this is used to automatically identify and measure individual Candida yeast cells in clusters.

Automation↗
PubMed1998

Synthetic peptides representing discontinuous CD4 binding epitopes of HIV-1 gp120 that induce T cell apoptosis and block cell death induced by gp120.

A vaccine against HIV-1 virus would block initial infection and must target conserved residues. Since initial infection depends on binding of the viral envelope protein gp120 to CD4 on the cell surface, the CD4 binding site of gp120 is a target for vaccine design. To identify the optimal biologically active site, we synthesized a series of 32-mer peptides, based on conserved residues in the C3 and C4 regions of gp120. These included three of five sequence discontinuous residues known to be involved in CD4 binding, one or two of which were substituted with alanine. We also synthesized a 44-mer peptide with an additional branch to incorporate an extra C4 region sequence including a fourth CD4 binding residue. All these peptides used an oxidized Cys-X-Cys bridge to link the discontinuous sequence elements in a manner suggested by the known conserved disulfide bridges in gp120. Polyclonal sera raised to these peptides indicate that they all contain both B and T lymphocyte epitopes. Binding of the peptides to CD4-transfected HeLa cells reveals a hierarchy dependent on the number of relevant CD4 binding residues present. Furthermore, antibody cross-linking of peptides bound to the surface of human T cells results in apoptosis that is similar to the known properties of gp120. The peptide incorporating three CD4 binding residues competitively inhibited gp 120-induced T lymphocyte apoptosis. Thus, we have synthesized novel, branched peptides incorporating conserved discontinuous sequences from two different conserved domains of HIV-1 gp120 that contain T and B lymphocyte epitopes and mimic biological functions of the native protein. These synthetic peptides are candidates for future vaccine development.

Amino Acid Sequence↗
PubMed1997

Effects of morning phototherapy on circadian markers in seasonal affective disorder.

BACKGROUND: The suppression of melatonin by light at 00.30 hours has been shown to be greater in winter than in summer on patients with seasonal affective disorder (SAD) but not in matched normal controls. METHOD: In this study 12 patients with SAD and 12 matched normal controls were exposed to morning light therapy in the winter. Melatonin profiles and sensitivity to light were measured before and after treatment. RESULTS: The SAD but not the normal group showed a phase advance of melatonin rhythms in response to phototherapy. There was an association between phase position and phase shift in the SAD but not in the normal group. CONCLUSIONS: There may be instability of circadian rhythms in SAD mediated by a high-amplitude phase response curve, rather than a fixed phase abnormality as had been previously suggested. This instability may be secondary to impaired serotoninergic function in the afferent pathways to the suprachiasmatic nuclei.

Adult↗
PubMed1995

Effect of fluoxetine on melatonin in patients with seasonal affective disorder and matched controls.

BACKGROUND: The aim was to investigate the secretion profile of melatonin and seasonal affective disorder before and after treatment with fluoxetine. METHOD: A six-week case-controlled study with repeated overnight blood sampling was conducted. Ten patients fulfilling the criteria for major depressive disorder, seasonal type, with a 29-item Hamilton Depression Rating Scale (HDRS) score of at least 20 were compared with ten age- and sex-matched healthy controls in a clinical laboratory. The effects of fluoxetine (20 mg/day) on the HDRS and melatonin concentration were measured. RESULTS: Fluoxetine significantly reduced melatonin levels in both groups. There was no significant difference in melatonin secretion between the groups. CONCLUSIONS: The effect of fluoxetine differs from tricyclics and fluvoxamine, both of which increase melatonin.

Adult↗
PubMed1994

Observation of pain behaviors during episodes of sickle cell disease pain.

OBJECTIVE: To assess the utility of a brief behavioral observation method to quantify pain. DESIGN: Correlational study. PATIENTS: 31 sickle cell disease (SCD) patients first seen in an outpatient clinic in painful crisis. OUTCOME MEASURES: Observed pain behaviors, physician rating of patient pain on a 0 to 10 scale, patient rating of pain on a 0 to 10 scale, and patient pain report from the McGill Pain Questionnaire. RESULTS: High interrater reliability for the brief behavioral observation was found, and observed pain behavior was found to correlate significantly with physician ratings of pain. CONCLUSIONS: This study is an important first step toward developing a systematic behavior-observation methodology for the analysis of SCD pain. The current methodology was found to be reliable and easily implemented in a busy, outpatient clinic.

Adult↗
PubMed1993

The Headache Self-Efficacy Scale: adaptation to recurrent headaches.

This paper describes the development, construct and discriminant validity, and incremental utility of a headache self-efficacy scale. The Headache Self-Efficacy Scale is a 51 item scale designed specifically for recurrent headache sufferers. It assesses individuals' belief that they are able to do the things necessary to prevent a moderately painful headache when confronted with personally relevant headache precipitants. High self-efficacy was associated with less depression, anxiety, and physical symptoms, and less use of passive coping strategies (P < .01), even when headache frequency, intensity and chronicity were controlled statistically. Self-efficacy also explained unique variance in psychological and somatic symptoms beyond that explained by locus of control and general self-efficacy. These findings suggest that adaptation to headaches is influenced by self-efficacy beliefs, and that the assessment of self-efficacy may provide useful information in the evaluation of recurrent headache sufferers.

Adaptation, Psychological↗
PubMed1991

Community-wide outbreak of group G streptococcal pharyngitis.

Although several outbreaks of group G beta-hemolytic streptococcal (GGBHS) pharyngitis have been described, doubt still remains regarding the etiologic role of GGBHS in acute pharyngitis beyond a limited number of situations. In the winter/spring of 1986/87, throat cultures were obtained from 222 consecutive children seen at a private pediatric office with acute pharyngitis and group A beta-hemolytic streptococci (GABHS) were recovered from 91 children (41%) and GGBHS from 56 children (25%). One patient had both GABHS and GGBHS isolated. This isolation rate of GGBHS was dramatically greater than in previous and subsequent years, and 67% of the GGBHS isolates occurred during an 8-week period. Results of DNA fingerprinting of the 57 isolates of GGBHS demonstrated that 43 (75%) appeared to be the same strain. The patients with GGBHS were comparable to those with GABHS with respect to clinical findings, antistreptolysin-O titer response, and clinical response to antibiotic therapy. However, patients with GGBHS were significantly older (P less than .05). This is the first well-documented, community-wide outbreak of GGBHS pharyngitis and the first respiratory outbreak of GGBHS pharyngitis in a pediatric population. GGBHS may be a more important cause of acute, treatable pharyngitis than had been previously recognized.

Adolescent↗
PubMed1990

The headache-specific locus of control scale: adaptation to recurrent headaches.

This paper describes the development, psychometric properties, and construct and incremental validity of a Headache-Specific Locus of Control Scale (HSLC). The HSLC is a 33 item scale designed specifically for recurrent headache sufferers. It assesses the individual's perceptions that headache problems and headache relief are determined primarily by: the individual's behavior (Internal factors), Health Care Professionals, or Chance factors. The psychometric properties of the HSLC were satisfactory. Among our findings were that: (1) the belief that headache problems and relief are determined by chance factors was associated with higher levels of depression, physical complaints, reliance on maladaptive pain coping strategies (p less than .001), and greater headache-related disability (p less than .01); (2) the belief that headache problems and relief are influenced primarily by the ministrations of health care professionals was associated with higher levels of medication use (p less than .01) and preference for medical treatment (p less than .001); and (3) the belief that headache problems are determined by the individual's responses and behaviors was associated with a preference for self-regulation treatment (p less than .01). These findings suggest adaptation to headache problems is influenced not only by the frequency and severity of the headache episodes, but by locus of control beliefs. The assessment of locus of control beliefs may provide useful information not typically obtained from standard medical evaluations.

Adaptation, Physiological↗
PubMed1990

Comparison of epidemic and endemic group G streptococci by restriction enzyme analysis.

Restriction enzyme profiles of group G beta-hemolytic streptococci associated with a point source outbreak and an outbreak of sporadic pharyngitis in two different communities were compared. To asses the epidemiologic utility of this approach for studying group G streptococci, DNA fingerprints of strains responsible for a point source outbreak of pharyngitis associated with the consumption of contaminated food were compared with DNA fingerprints of pharyngeal isolates from children with pharyngitis seen at a pediatric practice during a 6-month period. In each epidemiologic situation, a single strain characterized by a unique restriction enzyme pattern predominated. The results are compatible with the conclusion that human infections could be limited to a few strains of group G streptococci which have the capacity to spread through a given population. The restriction enzyme profiles proved to be a highly specific and precise means of evaluating strain relatedness and of providing further understanding of the epidemiology of group G streptococcal infections.

Connecticut↗
PubMed1989

McKusick-Kaufman syndrome: report of an instructive family.

We report on two sisters and their brother, all of whom are affected by McKusick-Kaufman syndrome. This sibship confirms autosomal recessive inheritance and the occurrence of the syndrome in Melanesians. It also demonstrates multisystem involvement in both sexes and illustrates difficulties in the diagnosis and management of hydrocolpos.

Abnormalities, Multiple↗
PubMed1989

Long-term maintenance of improvements achieved with (abortive) pharmacological and nonpharmacological treatments for migraine: preliminary findings.

This report presents the first prospective comparison of the long-term maintenance of reductions in recurrent migraine headaches achieved with (abortive) pharmacological and nonpharmacological (combined relaxation training and thermal biofeedback training) treatments. Nineteen of 21 (90%) successfully treated patients (50% or greater reduction in headache activity) were contacted for follow-up evaluation 3 years later. Migraine sufferers who had been treated with ergotamine were less likely to still be relying on the treatment they had received and more likely to have additional medical treatment for their headaches and to be using prophylactic or narcotic medication than were migraine sufferers who had been treated with relaxation/biofeedback training. However, daily headache recordings revealed that patients in both treatment groups continued to show lower headache activity at 3-year follow-up than prior to treatment. Although preliminary, these findings raise the possibility that improvements achieved with nonpharmacological treatment are more likely to be maintained without additional treatment than are similar improvements achieved with abortive pharmacological treatment.

Adult↗
PubMed1986

Lethal multiple pterygium syndrome: three consecutive cases in one family.

We report on three sib fetuses with the lethal multiple pterygium syndrome (LMPS), one case occurring in a twin pregnancy. All three fetuses had a cystic hygroma and hydrops was detected by ultrasound. The classification scheme for LMPS proposed by Hall [1984] is examined. With our present state of knowledge of this syndrome, subdivision on bone-fusion types does not appear to be justified. Antenatal detection by ultrasound is possible in most pregnancies with a second affected fetus because of cystic hygroma and hydrops. In the term or near-term infant in which ultrasound has not shown cystic hygroma or hydrops, a diagnosis of Pena-Shokeir type I syndrome should be considered because pterygia are a component of that syndrome but cystic hygroma and hydrops are not.

Abnormalities, Multiple↗
PubMed1986

Altered chromatin in childhood leukaemic lymphoblasts: association with virus-like particles.

An electron microscopic examination was made of masses identified as altered heterochromatin in the cytoplasm of childhood leukaemic lymphoblasts, and their relation to 'virus-like' particles (VLP). The masses were found to occur more frequently in leukaemic lymphoblasts than in normal lymphocytes, but abnormally frequent occurrence was a feature of non T rather than T or B lymphoblasts. Although these masses may be derived by phagocytosis of dead cells or cellular material, a more likely origin is by detachment of altered portions of the containing cell's own nucleus. Such in situ alterations in nuclei were seen in leukaemic lymphoblasts but not in normal lymphocytes. A close relation demonstrated between altered chromatin and VLP might suggest that VLP are a response to the presence of damaged chromatin. However, the occurrence in some VLP of solid cores and budding might make it more likely that VLP are viral, with chromatin damage as a morphologically recognizable cytopathic effect of their activity.

B-Lymphocytes↗