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Biomedical subjects

R Nicolson

Publications and source records attributed to R Nicolson.

36 records · Page 2Linked to original sources
PubMed1999

Velocardiofacial syndrome in childhood-onset schizophrenia.

OBJECTIVES: Deletion of chromosome 22q11 (velocardiofacial syndrome) is associated with early neurodevelopmental abnormalities and with schizophrenia in adults. The rate of 22q11 deletions was examined in a series of patients with childhood-onset schizophrenia (COS), in whom early premorbid developmental and cognitive impairments are more pronounced than in adult-onset cases. METHOD: Through extensive recruiting and screening, a cohort of 47 patients was enrolled in a comprehensive study of very-early-onset schizophrenia. All were tested with fluorescence in situ hybridization for deletions on chromosome 22q11. RESULTS: Three (6.4%) of 47 patients were found to have a 22q11 deletion. All 3 COS patients with 22q11 deletions had premorbid impairments of language, motor, and social development, although their physical characteristics varied. Brain magnetic resonance imaging revealed increased midbody corpus callosum area and ventricular volume in relation both to healthy controls and to other COS patients. CONCLUSIONS: The rate of 22q11 deletions in COS is higher than in the general population (0.025%, p < .001) and may be higher than reported for adult-onset schizophrenia (2.0%, p = .09). These results suggest that 22q11 deletions may be associated with an earlier age of onset of schizophrenia, possibly mediated by a more salient neurodevelopmental disruption.

Abnormalities, Multiple↗
PubMed1999

Clinical and neurobiological correlates of cytogenetic abnormalities in childhood-onset schizophrenia.

OBJECTIVE: Cytogenetic abnormalities are increased in schizophrenia, suggesting a possible etiologic contribution. However, their clinical and pathophysiologic roles in the disorder are unknown. To investigate this, a group of children and adolescents participating in a comprehensive study of childhood-onset schizophrenia were screened for chromosomal abnormalities, and their clinical and neurobiological correlates were examined. METHOD: Cytogenetic screening with the use of high-resolution banding, fluorescent in situ hybridization for chromosome 22q11 deletions, and molecular fragile X testing was undertaken in a group of 47 children and adolescents with very early onset of schizophrenia. Clinical, neurobiological (including brain morphometry), and risk factor measures of the subjects with cytogenetic abnormalities were compared with those of the remaining patients without cytogenetic anomalies. RESULTS: Five patients had previously undiagnosed cytogenetic abnormalities. Lower performance IQ and more pronounced premorbid developmental impairments were seen in this subgroup. Rates of obstetric complications, familial schizophrenia spectrum disorders, and familial eye tracking dysfunction were similar for the patients with and without cytogenetic abnormalities. CONCLUSIONS: Cytogenetic abnormalities appear to be increased in childhood-onset schizophrenia, suggesting an association with a very early age at onset. The data from the subgroup of patients with cytogenetic anomalies are consistent with a model in which a childhood onset of schizophrenia is due to a greater impairment of neurodevelopment secondary to the interaction of a number of factors, particularly genetic ones.

Adolescent↗
PubMed1999

Obstetrical complications and childhood-onset schizophrenia.

OBJECTIVE: Increased obstetrical complications have been reported in individuals with adult-onset schizophrenia, with several studies finding an association between such complications and an earlier age at onset. Consequently, obstetrical records were examined for individuals with childhood-onset schizophrenia to determine if birth complications were more prevalent. METHOD: The birth records of 36 patients with childhood-onset schizophrenia and 35 sibling comparison subjects were rated for birth complications by two psychiatrists who were unaware of group membership. RESULTS: There were no significant differences between the groups in rates of obstetrical complications. Patients with such complications did not have a relatively earlier age at onset of schizophrenia. CONCLUSIONS: A very early age at onset of schizophrenia is probably not due to birth complications.

Age of Onset↗
PubMed1998

An open trial of risperidone in young autistic children.

OBJECTIVE: To assess the benefits and side effects of risperidone in young autistic children. METHOD: In this open, prospective trial, subjects were treated with risperidone for 12 weeks. All subjects were started at 0.5 mg daily with individual titration to a maximum of 6 mg or 0.1 mg/kg daily. Behavioral ratings, completed by the investigators and the children's parents, included the Clinical Global Impressions (CGI), Children's Psychiatric Rating Scale, Conners Parent-Teacher Questionnaire, Childhood Autism Rating Scale, and Abnormal Involuntary Movement Scale. RESULTS: Ten boys, aged 4.5 to 10.8 years, were enrolled in the study and all completed the 12-week protocol. The mean final dose was 1.3 mg/day (range = 1 to 2.5 mg/day). On the basis of CGI-rated improvement, 8 of the 10 children were considered to be responders. Improvement was also demonstrated on the other scales. Transient sedation was common, and the children gained an average of 3.5 kg over the 12 weeks of the study. There was no evidence of either extrapyramidal symptoms or tardive dyskinesia. CONCLUSIONS: These results suggest that risperidone may be safe and leads to improvements in several behavioral symptoms in young children with autism. Controlled studies of risperidone in young autistic children are warranted.

Antipsychotic Agents↗
PubMed1998

47,XYY karyotypes and pervasive developmental disorders.

OBJECTIVE: The presence of a 47, XYY karyotype in boys with pervasive developmental disorders (PDDs) has rarely been described in the past. Herein, 2 boys with PDDs and a supernumerary Y chromosome are presented. METHODS: The case histories of the 2 patients are described along with the results of associated testing. The literature on psychosocial development as well as brain morphology and physiology in males with 47, XYY karyotypes is reviewed. RESULTS: Both boys had presentations typical of PDDs, one with autistic disorder and the other with PDD not otherwise specified. CONCLUSION: The finding that, in a clinic for children with developmental disorders, 2 of 40 male referrals had 47, XYY karyotypes suggests that the rate of this sex chromosome anomaly may be increased in PDDs. An extra Y chromosome may be related to abnormal brain development, which may, in turn, predispose vulnerable males to PDDs.

Adolescent↗
PubMed1996

Bridging the gap between theory and practice: a multimedia tutorial for students of voice therapy.

A computer-based tutorial for speech and language therapy students is described in which a digitized video-recording of a diagnostic interview with a voice-disordered client was dynamically linked to an on-screen transcript window. A student-centered tutorial package, which provided guidance through questions, assessment tasks, and commentary from an experienced speech and language pathologist as well as the lecturer in voice disorder, was constructed. Evaluation of the tutorial as an aid to active learning, including feedback from students and supervising clinicians, is reported and the role of this type of program as a preparation for clinical practice is discussed.

Adult↗
PubMed1994

The effect of oleic acid on the secretion of thyrotrophin and growth hormone by cultured rat anterior pituitary cells.

Elevation of non-esterified fatty acids (NEFA) in vivo is associated with abnormal control of TSH. To determine whether TSH secretion is directly inhibited by NEFA, as has been reported for GH, cultured rat anterior pituitary cells were exposed for 20 h to oleic acid in medium containing 7.7 x 10(-5) mol/l bovine serum albumin (BSA). In a molar ratio with albumin of 1.2 (total oleic acid 9 x 10(-5) mol/l), or greater, oleic acid inhibited basal GH secretion (maximum inhibition to 40% of control) while basal TSH was less affected, a ratio of 3 (2.3 x 10(-4) mol/l oleic acid) or greater causing a smaller degree of inhibition (maximum inhibition to 80% of control). In the presence of 10(-9) mol/l growth hormone-releasing hormone or 10(-8) mol/l TRH, inhibition was achieved at a ratio of 12 (9 x 10(-4) mol/l oleic acid) or greater. Basal TSH was less sensitive to inhibition by thyroxine (T4) in the presence of oleic acid/albumin at a ratio of 6 or greater, and inhibition by oleic acid was less than additive with T4 at a ratio of 6 or greater. Responses to tri-iodothyronine (T3) were unaffected at a ratio of 6 (4.6 x 10(-4) mol/l oleic acid), but a ratio of 12 inhibited the effects of both T3 and T4 on TSH.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Nucleotide sequence, organisation and structural analysis of the products of genes in the nirB-cysG region of the Escherichia coli K-12 chromosome.

The DNA sequence and derived amino-acid sequence of a 5618-base region in the 74-min area of the Escherichia coli chromosome has been determined in order to locate the structural gene, nirB, for the NADH-dependent nitrite reductase and a gene, cysG, required for the synthesis of the sirohaem prosthetic group. Three additional open reading frames, nirD, nirE and nirC, were found between nirB and cysG. Potential binding sites on the NirB protein for NADH and FAD, as well as conserved central core and interface domains, were deduced by comparing the derived amino-acid sequence with those of database proteins. A directly repeated sequence, which includes the motif -Cys-Xaa-Xaa-Cys-, is suggested as the binding site for either one [4Fe-4S] or two [2Fe-2S] clusters. The nirD gene potentially encodes a soluble, cytoplasmic protein of unknown function. No significant similarities were found between the derived amino-acid sequence of NirD and either NirB or any other protein in the database. If the nirE open reading frame is translated, it would encode a 33-amino-acid peptide of unknown function which includes 8 phenylalanyl residues. The product of the nirC gene is a highly hydrophobic protein with regions of amino-acid sequence similar to cytochrome oxidase polypeptide 1.

Amino Acid Sequence↗
PubMed1986

Serum relaxin in pregnancy.

Serum relaxin immunoactivity was measured by means of a porcine radioimmunoassay in a cross-sectional study of 302 normal singleton pregnancies. Concentrations in the third trimester were lower than in early and mid pregnancy. At term, relaxin levels in patients who went into spontaneous labour within a week of sampling were significantly lower than in those who did not. However, relaxin levels were highest during labour and fell almost to non-pregnant levels by the third postnatal day. Levels in twin pregnancies in the third trimester were higher than those in singleton pregnancies. Serial samples from 4 patients with a history of premature labour showed declining, very low levels in the only patient who subsequently had a preterm delivery. These results are compatible with the proposed roles of relaxin during pregnancy: namely, to maintain myometrial quiescence, facilitate uterine stromal remodelling during uterine growth, and promote cervical ripening at the onset of parturition.

Female↗
PubMed1986

Serum relaxin and pelvic pain of pregnancy.

Serum relaxin immunoreactivity was measured by means of a porcine relaxin radioimmunoassay in 35 patients with severe pelvic pain and pelvic joint instability during late pregnancy. Results were compared with a control group of 368 samples obtained throughout pregnancy from normal singleton pregnancies. Most of the relaxin concentrations in the study group were above the 95% confidence limits of the median for the corresponding gestational age in the control group. The difference in relaxin levels between the study and control groups in the third trimester was highly significant. Relaxin levels in patients with pelvic pain were close to normal non-pregnant levels by the third postnatal day. The highest relaxin levels during pregnancy were found in the patients who were the most incapacitated clinically. The results suggest that there may be an association between high serum relaxin levels and pelvic pain and joint laxity during late pregnancy.

Female↗
PubMed1986

Ripening of the human cervix and induction of labor with intracervical purified porcine relaxin.

In a randomized double-blind placebo-controlled trial involving 71 patients, a viscous gel containing distilled water or 1 or 2 mg pure porcine relaxin was instilled in the cervical canal on the evening before the surgical induction of labor. Eleven of 48 patients receiving relaxin labored overnight, whereas only one of 23 patients went into labor. Only the 2-mg dose significantly improved the mean cervical score compared with the placebo treatment; the effect was greatest in primigravid patients with unripe cervixes. Intracervical application appeared to confer no benefit over vaginal application in effecting cervical ripening or inducing labor. Systemic absorption of the porcine relaxin after its intracervical application was confirmed by the measurement of immunoreactive relaxin in a homologous porcine relaxin radioimmunoassay. Thus, the cervical ripening effect of exogenous relaxin may be mediated either systemically or by direct action at the site of local application. This trial confirms the responsiveness of the human term cervix to exogenous relaxin and supports the suggestion that endogenous relaxin may play a similar role at term in facilitating cervical ripening and parturition.

Administration, Intravaginal↗
PubMed1981

Oestrogen receptors and survival in early breast cancer.

Oestrogen receptor status was related to survival in 414 patients with primary breast cancer. Women with oestrogen receptors in their tumours survived significantly longer than those without receptors; this was true for both premenopausal and postmenopausal women and also when the patients were subdivided into those with and without axillary metastases. Patients with axillary metastases and no oestrogen receptors in their tumours had the worst prognosis, while women with axillary metastases and oestrogen receptors had a death rate similar to that of women with no axillary metastases and no receptors. Patients without oestrogen receptors and with no axillary metastases were identified as a high-risk group, and it would seem appropriate to include such patients in future trials for adjuvant therapy in early breast cancer.

Breast Neoplasms↗
PubMedDate not supplied

Children and adolescents with psychotic disorder not otherwise specified: a 2- to 8-year follow-up study.

Although psychotic phenomena in children with disruptive behavior disorders are more common than expected, their prognostic significance is unknown. To examine the outcome of pediatric patients with atypical psychoses, a group of 26 patients with transient psychotic symptoms were evaluated with clinical and structured interviews at the time of initial contact (mean age, 11.6 +/- 2.7 years) and at follow-up 2 to 8 years later. Measures of functioning and psychopathology were also completed at their initial assessment. Risk factors associated with adult psychotic disorders (familial psychopathology, eyetracking dysfunction in patients and their relatives, obstetrical complications, and premorbid developmental course in the proband) had been obtained at study entry. On follow-up examination (mean age, 15.7 +/- 3.4 years), 13 patients (50%) met diagnostic criteria for a major axis I disorder: three for schizoaffective disorder, four for bipolar disorder, and six for major depressive disorder. The remaining 13 patients again received a diagnosis of psychotic disorder not otherwise specified (NOS), with most being in remission from their psychotic symptoms. Among this group who had not developed a mood or psychotic disorder, disruptive behavior disorders were exceedingly common at follow-up and were the focus of their treatment. Higher initial levels of psychopathology, lower cognitive abilities, and more developmental motor abnormalities were found in patients with a poor outcome. Obstetrical, educational, and family histories did not differ significantly between the groups. Through systematic diagnostic evaluation, children and adolescents with atypical psychotic disorders can be distinguished from those with schizophrenia, a difference with important treatment and prognostic implications. Further research is needed to delineate the course and outcome of childhood-onset atypical psychoses, but preliminary data indicate improvement in psychotic symptoms in the majority of patients and the development of chronic mood disorders in a substantial subgroup.

Adolescent↗