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Biomedical subjects

R L Robinson

Publications and source records attributed to R L Robinson.

At least 19 recordsLinked to original sources
PubMed2004

Outcomes of newly referred neurology outpatients with depression and pain.

BACKGROUND: Although depression and pain are common in neurology outpatients, patient factors influencing chronicity are poorly understood. The authors sought to determine the predictors of persistent depression and pain symptoms at 3 and 12 months after an initial outpatient neurology clinic visit. METHODS: Consecutive new patients (n = 483) at three clinics completed the Patient Health Questionnaire nine-item depression scale and the Brief Pain Inventory at baseline and at 3- and 12-month follow-up. Multivariate analysis was used to model 3- and 12-month depression and pain severity. RESULTS: The prevalence of depression and pain at baseline/3/12 months was depression 33%/28%/27% and pain 66%/61%/62%. Independent predictors of depression severity at follow-up were more severe depression and pain at baseline and less improvement in pain (model r(2) = 0.53 to 0.56). Independent predictors of pain intensity at follow-up were more severe pain and depression at baseline and less improvement in depression (model r(2) = 0.44 to 0.46). Health care utilization and impairments in health status were greatest in patients with coexisting depression and pain and least in those with neither depression nor pain. CONCLUSIONS: Depression and pain symptoms in neurology outpatients often persist for at least 12 months and have long-term negative effects on patients' health status. Pain is more likely to persist in patients with depression, and depression is more likely to persist in those with coexistent pain.

Adult↗
PubMed2004

Hybridization and contemporary evolution in an introduced cichlid fish from Lake Malawi National Park.

Rapidly evolving systems offer the chance to observe genetic and phenotypic change in real time. We exploit a well-characterized introduction of cichlid fish into Lake Malawi National Park to document a short history of habitat colonization and the evolution of genes and colour pattern. In the early 1960s, a fish exporter introduced individuals of Cynotilapia afra to a single site (Mitande Point) of Thumbi West Island and, as late as 1983, the species was confined to this location. In 2001, C. afra had colonized the entire perimeter of Thumbi West. In July of that year, we sampled C. afra individuals from six sites around the island and scored variation in dorsal fin colour as well as allelic diversity at six microsatellite loci. We found that, in two decades, C. afra had diverged into genetically distinct, phenotypically different northern and southern populations. We observed a high proportion of hybrids between the introduced C. afra and the native Metriaclima zebra on the southern coast of Thumbi West, and speculate that hybridization is facilitated by low water clarity at these windward sites. The short history of C. afra at Thumbi West is a microcosm of contemporary evolutionary divergence and may provide the opportunity to study the process from start to finish in genetic detail.

Animals↗
PubMed2003

Recent advances in the diagnosis of malignant hyperthermia susceptibility: how confident can we be of genetic testing?

Malignant hyperthermia (MH) is a condition that manifests in susceptible individuals only on exposure to certain anaesthetic agents. Although genetically heterogeneous, mutations in the RYR1 gene (19q13.1) are associated with the majority of reported MH cases. Guidelines for the genetic diagnosis for MH susceptibility have recently been introduced by the European MH Group (EMHG). These are designed to supplement the muscle biopsy testing procedure, the in vitro contracture test (IVCT), which has been the only means of patient screening for the last 30 years and which remains the method for definitive diagnosis in suspected probands. Discordance observed in some families between IVCT phenotype and susceptibility locus genotype could limit the confidence in genetic diagnosis. We have therefore assessed the prevalence of 15 RYR1 mutations currently used in the genetic diagnosis of MH in a sample of over 500 unrelated European MH susceptible individuals and have recorded the frequency of RYR1 genotype/IVCT phenotype discordance. RYR1 mutations were detected in up to approximately 30% of families investigated. Phenotype/genotype discordance in a single individual was observed in 10 out of 196 mutation-positive families. In five families a mutation-positive/IVCT-negative individual was observed, and in the other five families a mutation-negative/IVCT-positive individual was observed. These data represent the most comprehensive assessment of RYR1 mutation prevalence and genotype/phenotype correlation analysis and highlight the possible limitations of MH screening methods. The implications for genetic diagnosis are discussed.

Chromosomes, Human, Pair 19↗
PubMed2003

Prevalence and impact of depression and pain in neurology outpatients.

BACKGROUND: We examined the prevalence and health related quality of life (HRQoL) of depression and/or pain in neurology outpatients. METHODS: Patients at outpatient clinics completed depression, pain, and HRQoL scales. Group comparisons between those with pain alone, depression alone, both conditions, and neither condition were done. RESULTS: Overall, pain was present in 2/3 and depression in 1/3 of patients. Pain with depression was present in 25%; 75% of depressed patients had pain. These conditions had significant negative impact on mental and physical health status scores. The odds ratio (OR) for having pain was significantly increased in women (OR 2.0), those with depression (OR 2.4), and those with neuropathy/neuromuscular (OR 3.8) or pain syndromes (OR 4.8). The odds of having depression were increased in those with pain (OR 2.4) and with cognitive (OR 4.8) or cerebrovascular (OR 3.3) diagnoses. Neurologists were more likely to recognise and treat pain than depression. CONCLUSIONS: Depression and pain are common in newly referred neurology outpatients and have substantial negative effects on patients' physical and mental health. Pain is more likely than depression to be recognised and treated by neurologists.

Adult↗
PubMed2003

Characterizing blood pressure control in individuals with Type 2 diabetes: the relationship between clinic and self-monitored blood pressure.

AIMS: To determine the relationship between blood pressure (BP) measurement in the clinic and self-monitored blood pressure (SMBP); and to evaluate the accuracy of self-reported data in patients with Type 2 diabetes treated intensively for hypertension. METHODS: Seventy subjects had baseline and 1-week follow-up clinic BP measured using an Omron 907 automated device. During a contemporaneous 14-day period these subjects measured their BP at least four times each day using an Omron IC semiautomatic portable monitor which, unknown to them, contained an onboard memory capable of storing BP with corresponding time and date. RESULTS: There was no significant difference between mean clinic and mean self-monitored BP. Correlations between clinic BP and SMBP were r=0.61 (P<0.0001) for systolic BP and r=0.69 (P<0.0001) for diastolic BP. Clinic BP classified 56 subjects as uncontrolled hypertension (BP > or = 130/80 mmHg, adjusted for diabetes) and 14 subjects as controlled hypertension. Using World Health Organization-International Society of Hypertension criteria for SMBP (> or = 125/75 mmHg), 55 cases of clinic classified uncontrolled hypertension were confirmed, resulting in 98% sensitivity. Clinic and SMBP agreed in one case of controlled hypertension, resulting in 7% specificity. For all subjects, the median percent of values exceeding SMBP criteria for controlled hypertension was systolic 92% and diastolic 70%. Self-reporting precision averaged 89+/-10% (range 45-100%); under-reporting was 25+/-16% (ranging from 0 to 56%) and over-reporting was 12+/-15% (ranging from 0 to 46%). The overall logbook mean was not significantly different from the downloaded data from the Omron IC(R) monitors. CONCLUSIONS: SMBP was able to identify 13 patients with uncontrolled hypertension who, by clinic BP measurement, had been classified as controlled.

Adult↗
PubMed2002

No evidence of mutations in the CACNA1S gene in the UK malignant hyperthermia population.

BACKGROUND: Malignant hyperthermia (MH) is an inherited, potentially fatal, pharmocogenetic disorder triggered by certain anaesthetic agents. In light of the reported genetic heterogeneity for the disorder and the recent introduction of DNA testing guidelines for the trait, we have assessed the role of the CACNA1S gene in MH susceptibility in UK patients. Linkage to this locus has previously been demonstrated in several European MH families. METHODS AND RESULTS: We screened 200 unrelated MH-susceptible individuals for known CACNA1S mutations. With the aim to characterize further novel mutations at this locus, functionally relevant regions of the gene were also sequenced in 10 unrelated individuals from families where the involvement of other MH susceptibility loci was unlikely. No sequence variations were detected in any of the patients investigated. CONCLUSIONS: Defects in CACNA1S are not a major cause of MH in the UK population. Diagnostic screening of this gene is unlikely to be of value to UK MH patients in the near future.

Calcium Channels, L-Type↗
PubMed2001

How many species of cichlid fishes are there in African lakes?

The endemic cichlid fishes of Lakes Malawi, Tanganyika and Victoria are textbook examples of explosive speciation and adaptive radiation, and their study promises to yield important insights into these processes. Accurate estimates of species richness of lineages in these lakes, and elsewhere, will be a necessary prerequisite for a thorough comparative analysis of the intrinsic and extrinsic factors influencing rates of diversification. This review presents recent findings on the discoveries of new species and species flocks and critically appraises the relevant evidence on species richness from recent studies of polymorphism and assortative mating, generally using behavioural and molecular methods. Within the haplochromines, the most species-rich lineage, there are few reported cases of postzygotic isolation, and these are generally among allopatric taxa that are likely to have diverged a relatively long time in the past. However, many taxa, including many which occur sympatrically and do not interbreed in nature, produce viable, fertile hybrids. Prezygotic barriers are more important, and persist in laboratory conditions in which environmental factors have been controlled, indicating the primary importance of direct mate preferences. Studies to date indicate that estimates of alpha (within-site) diversity appear to be robust. Although within-species colour polymorphisms are common, these have been taken into account in previous estimates of species richness. However, overall estimates of species richness in Lakes Malawi and Victoria are heavily dependent on the assignation of species status to allopatric populations differing in male colour. Appropriate methods for testing the specific status of allopatric cichlid taxa are reviewed and preliminary results presented.

Africa↗
PubMed2000

Genetic population structure indicates sympatric speciation of Lake Malawi pelagic cichlids.

Allopatric processes of speciation have routinely been presented to explain the extraordinary radiation of the East African Great Lakes cichlid fish species flocks. The 21 or more species of pelagic cichlids within the Lake Malawi flock appear to have lake-wide distributions that challenge such a concept. Data from six microsatellite DNA loci indicate single, panmictic populations across the lake of three Diplotaxodon species. Levels of variability at these loci suggest that populations have been large and stable. Mitochondrial DNA sequence data (872 bp of control region + 981 bp of the NADH-2) from 90 species, representing all major clades within the Lake Malawi flock, indicate reciprocal monophyly of the pelagic clade. We suggest that these data support a hypothesis that speciation in sympatry is more plausible (and widespread) within the cichlid species flocks than previously thought.

Animals↗
PubMed2000

Multiple interacting gene products may influence susceptibility to malignant hyperthermia.

Malignant hyperthermia (MH) is a potentially lethal disorder triggered in susceptible individuals on exposure to common anaesthetic agents. Crises reflect the consequences of disturbed skeletal muscle calcium homeostasis. MH is an autosomal dominant, genetically heterogeneous trait. Defects in a single major gene have been assumed to determine susceptibility status in individual families. However, in some pedigrees phenotypic and genotypic data are discordant. One explanation, in contrast to the current genetic model, is that susceptibility is dependent upon the effects of more than one gene. Using the transmission disequilibrium test we assessed the involvement of 8 MH candidate loci (RYR1, CACNA1S, CACNA2D1, MHS4 at 3q13.1, MHS6 at 5p, LIPE, DM1, dystrophin) by analysis of data from 130 MH nuclear families. Results suggested that variations in more than one gene may influence MH susceptibility in single families.

Anesthetics, Inhalation↗
PubMed2000

Effect of antidepressant choice on the incidence and economic intensity of hospitalization among depressed individuals.

This study identified differences in hospital utilization for mental health problems among depressed patients initially treated with selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs). A retrospective sample of 2,557 patients was obtained from a private insurance claims database. Quasi-experimental, two-stage multivariate regression modeling was used to estimate the likelihood of hospitalization and subsequent inpatient expenditures. Only 2% of the sample were hospitalized, and the average expenditures per admitted patient was about $8,000. Patients initially prescribed sertraline had the same likelihood of hospitalization for a mental health problem as patients prescribed TCAs. Patients initially prescribed fluoxetine were half as likely to be hospitalized as patients initially prescribed TCAs. Once hospitalized, no differential effects of a specific antidepressant on inpatient expenditures were found.

Adolescent↗
PubMed2000

Premenstrual symptom severity: impact on social functioning and treatment-seeking behaviors.

Our purpose was to understand premenstrual symptomatology and treatment-seeking behaviors by examining three subjective measurement approaches for premenstrual syndrome (PMS), their relationship to social functioning interference, and the role of symptom severity in a broader model of help seeking for PMS. Cross-sectional data were obtained from 1022 mail survey respondents who were derived from a nationally representative random sample of women, aged 18-49, experiencing regular menstrual cycles. Statistical analyses included Pearson correlations, chi-square tests, t tests, and logistic regression. The three symptom severity measures (a global self-appraisal, summative symptom counting, and categorical-configural) were strongly intercorrelated, ranging from. 60 to.78 (p < 0.001), and were correlated with interference in social and occupational functioning domains, ranging from.44 to.77 (all p < 0.001). A global self-report measure identified 4.9% of women with severe symptoms, whereas a DSM-IV-adapted approach identified 11.3% with premenstrual dysphoric disorder (PMDD) symptoms (of whom 92% also reported social interference). PMS treatment seeking was predicted by older age, PMS symptoms experienced in most cycles, greater self-reported symptom severity, greater overall use of healthcare services, and less negative attitudes toward PMS (all p < 0.05). These findings support the feasibility of clinician's use of brief screening approaches for PMDD, especially using short summative symptom rating scales. Women underidentify the severity of their PMS difficulties despite the reported difficulties associated with consistent social and occupational interference in most life domains. They are also reluctant to seek help for treatable PMS symptoms because of attitudinal barriers regardless of the severity of their PMS symptoms.

Adolescent↗
PubMed2000

Racial variation in antidepressant treatment in a Medicaid population.

BACKGROUND: Many studies have found racial and socioeconomic variation in medical care for a variety of conditions. Undertreatment of depression for individuals of all races is a concern, but especially may affect vulnerable populations such as Medicaid recipients and minorities. With this study, we examine racial differences in the antidepressant usage in a Medicaid population. METHOD: Treatment of 13,065 depressed patients (ICD-9-CM criteria) was examined in a state Medicaid database covering the years 1989 through 1994. Treatment differences were assessed in terms of whether an antidepressant was received at the time of the initial depression diagnosis and the type of antidepressant prescribed (tricyclic antidepressants [TCAs] vs. selective serotonin reuptake inhibitors [SSRIs]), using logistic regression techniques. RESULTS: African Americans were less likely than whites to receive an antidepressant at the time of their initial depression diagnosis (27.2% vs. 44.0%, p < .001). Of those receiving an antidepressant, whites were more likely than African Americans to receive SSRIs versus TCAs. These findings remained even after adjusting for other covariates. CONCLUSION: Despite the easy availability of effective treatments, we found that only a small portion of depressed Medicaid recipients receive adequate usage of antidepressants. Within this Medicaid population, limited access to treatment was especially pronounced among African Americans. Racial differences existed in terms of whether an antidepressant was received and the type of medication used.

Adult↗
PubMed1999

Segregation of malignant hyperthermia, central core disease and chromosome 19 markers.

Malignant hyperthermia (MH) is an autosomal dominant disorder presenting under general anaesthesia. It is occasionally associated with a myopathy, central core disease (CCD), named after its predominant histochemical characteristic. The penetration of CCD is variable, but typically affected individuals show delayed motor milestones in infancy and remain physically compromised. It was thought until recently that individuals with CCD were always susceptible to MH. Individuals from eight CCD families were screened for the presence of 13 mutations in the skeletal muscle ryanodine receptor gene, reported previously to be associated with MH and/or CCD: none was detected. In seven of these families, where CCD and MH co-existed, we examined the segregation of CCD, MH susceptibility and chromosome 19q markers. In four families, there was complete co-segregation between MH, CCD and the chromosome 19 markers, but in one large pedigree there was a clear lack of segregation of CCD with either MH or chromosome 19 markers and there was no segregation between MH and these markers. This is unequivocal evidence that CCD, in common with MH, is genetically heterogeneous. In the two other families, CCD segregated with chromosome 19 markers but not all individuals with CCD were susceptible to MH. We recommend determination of MH susceptibility in all patients with CCD, irrespective of the MH status of their relatives with CCD.

Adult↗
PubMed1998

Patient outcomes after knee replacement.

A prospective, observational cohort investigation was performed to help understand the impact of knee replacement on patients with knee osteoarthritis in community practice. Of those, 291 patients (330 knees) were eligible and willing to participate. Forty-eight orthopaedic surgeons referred 563 patients from 25 institutions within the state of Indiana. Demographics, patient completed health status, satisfaction, independent radiographic measures, surgeon reported intraoperative factors, hospital discharge factors, and independent physical examinations were recorded. A minimum 2-year followup was obtained in 92% of the patients. At followup, 88% were satisfied, 3% were neutral, and 9% were dissatisfied with the results of their knee surgery. The physical composite score improved from 27.4 +/- 0.4 (range, 13.3-50.3) to 37.7 +/- 0.7 (range, 12.9-61.3) at two years. Maximal improvement in physical composite score was seen in patients who had their surgery performed in institutions that performed greater than 50 knee replacements per year in patients with Medicare insurance; who had a better mental health status at baseline; who had surgery performed on Monday, Friday, or Saturday; who were older; who were treated with a posterior cruciate sparing device; and who had worse preoperative function. A lower likelihood of complications were found with surgeons who performed greater than 20 knee replacements per year; midweek surgeries; in patients with more severe preoperative knee dysfunction; patients with fewer comorbidities; patients with less preoperative stiffness; patients being treated by younger surgeons; and in patients undergoing unilateral knee replacement. Among voluntarily participating physicians, knee replacement can be a highly effective medical technology with high levels of patient satisfaction and low rates of complications.

Age Factors↗
PubMed1997

A genome wide search for susceptibility loci in three European malignant hyperthermia pedigrees.

Malignant hyperthermia (MH) is an autosomal dominant disorder which is potentially lethal in susceptible individuals on exposure to commonly used inhalational anaesthetics and depolarising muscle relaxants. Crises reflect the consequences of disturbed skeletal muscle calcium homeostasis. Susceptibility was first localised to chromosome 19q13.1 and the skeletal muscle ryanodine receptor, RYR1 (the calcium release channel of the sarcoplasmic reticulum). Defects in this gene have been identified which cosegregate with the MHS phenotype and evidence as to their potential causal roles has accumulated. MH has, however, been shown to be genetically heterogeneous, additional loci on chromosomes 3q, 17q and 7q being proposed. Pedigrees remain in Europe where linkage status is still unclear. In a collaborative search of the human genome conducted with three pedigrees whose disease status was classified according to the European IVCT protocol we have evidence to suggest that at least two further loci exist for MH susceptibility. One of these locates to chromosome 1q, the site of a candidate gene, CACNL1A3, encoding the alpha-subunit of the dihydropyridine receptor. The second region resides on chromosome 5p to where no known candidate has been mapped to date. The third family exhibited inconclusive results which suggests the existence of at least one other locus. This study adds to the evidence for considerable genetic heterogeneity in MH and will provide a route to further our understanding of the molecular pathology of the condition.

Calcium Channels↗
PubMed1997

The G1021A substitution in the RYR1 gene does not cosegregate with malignant hyperthermia susceptibility in a British pedigree.

A single base change in the RYR1 gene encoding the skeletal muscle ryanodine receptor (calcium-sensitive calcium-release channel of the sarcoplasmic reticulum), resulting in the substitution of G1021 by A, has been proposed to underlie malignant-hyperthermia (MH) susceptibility in as many as 10% of cases in the European population. As part of our mutation-screening program in MH-susceptible (MHS) individuals, we have investigated this substitution in individuals from 151 unrelated British MHS families and have detected G1021A heterozygotes in 7 families. This mutation was not found in 156 unrelated MH-negative (MHN) individuals. We also examined eight families with central core disease (CCD): the mutation did not occur in any family members of any disease status (affected or unaffected for CCD, MHS, or MHN). In one large family, the G1021A mutation was found but did not show complete cosegregation with MH susceptibility: it occurred in only 7/12 MHS individuals in the kinship, and susceptibility was inherited from parents who were G1021 homozygotes, as well as from parents who were heterozygotes. On the basis of these findings, it is clearly unreliable at present to offer presymptomatic DNA testing for MH status, even in families in which a mutation has been detected.

Calcium Channels↗