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Biomedical subjects

B Kerr

Publications and source records attributed to B Kerr.

34 records · Page 2Linked to original sources
PubMed1991

Localisation of the MRX3 gene for non-specific X linked mental retardation.

A family is described with five affected males segregating a new gene for non-specific X linked mental retardation (MRX). Linkage analysis localised the gene at Xq28-qter. The maximum lod score was 2.89 with DXS52 (St14) at theta = 0.0. A recombinant was observed with DXS304 (U6.2) defining the proximal limit to the localisation. No evidence for linkage was determined using markers at several points along the remainder of the X chromosome, including the regions known to contain MRX1 and MRX2. This delineates the third gene for non-specific X linked mental retardation, MRX3.

Adult↗
PubMed1991

Non-specific X linked mental retardation.

Non-specific X linked mental retardation (MRX) is mental retardation in persons of normal physical appearance who have no recognisable features apart from a characteristic pedigree. Review of published reports shows that there is clinical variability in the degree of mental retardation within families and genetic heterogeneity, based on gene localisation, between families. We propose a classification based on genetic localisation and a set of minimal clinical features that should be recorded in the hope of identifying possible specific phenotypes.

Genetic Linkage↗
PubMed1991

Concentration-related effects of morphine on cognition and motor control in human subjects.

Morphine and other opioid analgesics may interfere with normal cognition and motor function when the drugs are used for long-term treatment of pain. We used individually tailored steady-state drug infusions to identify the nature and extent of cognitive and motor effects of the mu-receptor-selective opioid morphine in healthy volunteers. The tailored infusions allowed evaluation of cognitive and motor effects at three sequential, constant plasma concentrations of morphine in each subject. Compared with functional assessments obtained in a separate saline infusion day, infusions of morphine to plasma concentrations in the usual therapeutic range for analgesia caused significant impairments of some but not all elements of cognitive and motor function. The time needed to encode and process serially presented verbal information increased and the ability to maintain low consistent levels of force decreased during the morphine infusion. We also assessed verbal recall 3 hours after the morphine and saline infusions. Delayed recall of information presented during the morphine infusion was significantly impaired. Our results demonstrate that morphine can interfere with cognitive and motor performance at plasma drug concentrations within the usual therapeutic range.

Adult↗
PubMed1990

The impact of medication resistance and continuation pharmacotherapy on relapse following response to electroconvulsive therapy in major depression.

After clinical response to electroconvulsive therapy (ECT), 58 patients with major depressive disorder were followed for 1 year or until relapse. The rate of relapse was substantially higher in patients who had failed adequate antidepressant medication trials prior to ECT than in patients not determined to be medication resistant. Adequacy of post-ECT pharmacotherapy was only marginally related to likelihood of relapse. The subgroup of patients who appeared to benefit from adequate post-ECT pharmacotherapy were those who did not receive an adequate medication trial prior to ECT. The findings call into question the common practice of administering as continuation pharmacotherapy following ECT the same class of medications that patients had failed with during the acute episode prior to ECT. The findings also indicate that resistance to antidepressant medication is a strong predictor of relapse following response to ECT.

Aged↗
PubMed1987

The chronopharmacokinetics of indomethacin suppositories in healthy volunteers.

The pharmacokinetics of a single 100 mg indomethacin suppository were studied in 12 healthy volunteers on two occasions at least 7 days apart. Suppositories were administered in randomised order at 9.00 and 21.00 hours to see if there was evidence of a diurnal variation in kinetic parameters. The study failed to show a significant change in single dose kinetics with the time of suppository administration. This is in contrast to previous work [1] demonstrating a circadian rhythm in the kinetics of a single oral dose of indomethacin. This suggests that the chronopharmacokinetics of indomethacin is dependent on the function of the upper gastrointestinal tract.

Adult↗
PubMed1987

Effects of electrode placement on the efficacy of titrated, low-dose ECT.

This double-blind, random-assignment study contrasted the relative efficacy of bilateral and unilateral right ECT with a low-dose titration procedure. In 52 patients with primary major depressive disorder, bilateral ECT was markedly superior in short-term symptom reduction to unilateral right ECT. The two conditions did not differ in the duration of generalized seizures or in the number of treatments administered to achieve clinical response. The findings challenge the claim that the elicitation of generalized seizure is, in and of itself, sufficient for the antidepressant properties of ECT. Rather, a dose in excess of seizure threshold may contribute to the efficacy of ECT, particularly with a unilateral right electrode placement.

Clinical Trials as Topic↗
PubMed1985

Cognitive spatial processing and the regulation of posture.

Subjects performed the Brooks (1967) spatial and nonspatial memory tasks either while sitting or while maintaining a difficult standing balance position. The balance task disrupted spatial but not nonspatial memory performance. Balance steadiness during spatial and nonspatial memory conditions did not differ. These results suggest that cognitive spatial processing may rely on neural mechanisms that are also required for the regulation of posture.

Adult↗
PubMedDate not supplied

Nomenclature guidelines for X-linked mental retardation.

Nomenclature guidelines are proposed for non-specific and for syndromal forms of X-linked mental retardation. Non-specific mental retardations (MRX) are given unique symbols for each family (MRX1, MRX2, MRX3 ...). Syndromal mental retardations (MRXS) which do not as yet have specific symbols are given unique interim symbols for each syndrome (MRXS1, MRXS2, MRXS3 ...). The prerequisite for assignment of serial MRX and MRXS gene symbols is a minimum lod score (or multipoint lod score) of +2 between the MR locus and one or more X chromosome markers. Prior approval of availability for proposed gene symbols must be obtained from the Nomenclature Committee of the Human Gene Mapping Workshops.

Chromosome Mapping↗
PubMedDate not supplied

Localization of non-specific X-linked mental retardation genes.

Gene localization was determined by linkage analysis in 5 families with non-specific X-linked mental retardation (MRX) and were MRX1, Xp11.4-q21.31; MRX10, Xp21.3-p11.4; MRX11, Xp21.3-p11.22; MRX12, Xp21.3-q21.1; and MRX13, Xp22.3-q21.22. Four of these localizations cross the dystrophin brain promoter, a candidate locus for MRX. None of the affected individuals who were tested showed variation suggestive of a deletion. No consistent clinical features were observed between or within 4 of the 5 families. In MRX12, prematurity or low birth weight, hypotelorism and short stature were seen in several affected males. Heterozygote manifestations occurred in 3 families. There was no evidence to suggest involvement of the same gene in more than one family, nor to clinically separate these families into distinct genetic entities. Non-overlapping localizations for MRX1 and MRX10 demonstrate the existence of at least 2 separate loci among these 5 families.

Chromosome Mapping↗
PubMedDate not supplied

Relative response of endogenous and non-endogenous symptoms to electroconvulsive therapy.

A sample of patients with endogenous depression (RDC), who had only a partial response to electroconvulsive therapy (ECT), was identified from a larger group of patients participating in a study of the affective and cognitive effects of low-dose titrated ECT. Using symptom scores on the Hamilton Rating Scale for Depression, subscales were constructed to reflect Klein's formulation of endogenomorphic depression, the RDC for endogenous subtype, and the DSM-III criteria for melancholia. Regardless of the subscale used, no evidence was obtained that endogenous symptoms were more responsive to ECT than non-endogenous symptoms.

Adult↗
PubMedDate not supplied

Skeletal abnormalities in Meckel syndrome.

Meckel syndrome is an autosomal recessive condition with a wide phenotypic variation. The most consistent features are cystic kidneys and intrahepatic bile duct anomalies, frequently accompanied by central nervous system (CNS) malformations and polydactyly. Approximately one sixth of all cases also show skeletal anomalies. We present two cases, siblings born to a consanguineous couple, in whom there was a striking curvature and shortening of the long bones in addition to cystic kidneys, CNS abnormalities, and polydactyly. Histological examination of the long bones in the second affected sibling showed mid-diaphysial ectopic cartilaginous growth plates differentiating the long bone changes from other skeletal dysplasias with similar radiological features.

Bile Ducts, Intrahepatic↗