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Biomedical subjects

A David

Publications and source records attributed to A David.

At least 163 records · Page 9Linked to original sources
PubMed1995

Activation of area V5 by visual perception of motion demonstrated with echoplanar MR imaging.

Cortical activation in visual association areas known to be responsible for the perception of motion was investigated in two volunteers who viewed a projected animated cartoon periodically "run" and "frozen" during collection of echoplanar MR images. Ten axial, contiguous, 5 mm thick, T2-weighted, gradient-echo images (TE 40 ms, TR 3000 ms) depicting BOLD contrast were acquired through the occipital lobe using a GE Signa 1.5 T system with an advanced NMR operating console. Images were analysed by time series regression modelling estimating power in the MR signal at the ON-OFF frequency of motion. Highly significant activation in response to motion perception was identified in both subjects bilaterally in area V5.

Echo-Planar Imaging↗
PubMed1995

Are there neurological and sensory risk factors for schizophrenia?

The association between left-handedness, epilepsy, and hearing impairment with schizophrenia was investigated using data from a cohort of 50,000 male Swedish conscripts linked to the Swedish National Register of Psychiatric Care. Though epilepsy was rare in this cohort, no association with schizophrenia was found. Left-handedness was associated with neither schizophrenia nor other psychoses. The study shows that, when studied from a population base, the apparent increase in neurodevelopmental anomalies in schizophrenia may be an artefact of bias. However, schizophrenia was 1.81 (95% CI 1.2-2.7) times higher amongst those with severe hearing loss, which may be preventable.

Adolescent↗
PubMed1995

Smooth muscle tumors associated with X-linked Alport syndrome: carrier detection in females.

X-linked Alport syndrome (AS) associated with diffuse esophageal leiomyomatosis (DL) has been reported to be due to deletions removing the 5' ends of both the COL4A5 and COL4A6 genes, encoding the alpha 5 and alpha 6 chains of type IV collagen, respectively, whereas a variety of mutations in COL4A5 has been identified in patients with AS alone. Here we report three additional DL-AS patients who also display deletions removing the 5' ends of both COL4A5 and COL4A6 genes. Furthermore, we tracked the mutation in 15 females belonging to six DL-AS families by gene copy number determination. We found that, like AS, DL is transmitted as an X-linked dominant trait but, contrary to AS, DL is fully penetrant and completely expressed in females. These results are in agreement with our previous work suggesting that DL could be due to a dominant effect of an abnormal alpha 6 (IV) collagen chain. Finally, we have detected a similar deletion of the COL4A5 and COl4A6 genes in a DL affected female who showed no sign of nephropathy, demonstrating the AS carrier status of this DL patient. These results emphasize the importance of molecular analysis of female DL patients for genetic counseling.

Adult↗
PubMed1995

Three glycosylated polypeptides secreted by several embryogenic cell cultures of pine show highly specific serological affinity to antibodies directed against the wheat germin apoprotein monomer.

Embryogenic tissues of Pinus caribaea Morelet var hondurensis produce extracellular proteins; among them germins have been identified. Two-dimensional electrophoresis followed by electroblotting onto a polyvinylidene difluoride membrane allowed isolation and N-terminal amino acid sequencing of extracellular GP111, which is present within the five embryogenic cell lines studied. The amino acid sequence showed strong homologies with the sequences of germins deduced from cDNA sequencing, starting at the same amino acid position but one, compared with other sequences of mature germins deduced from protein sequencing. Immunoblots of embryogenic and nonembryogenic extracellular proteins indicated that the polypeptide GP111 plus two others with similar relative molecular mass values are present in embryogenic cell lines but not in nonembryogenic ones. They were recognized by an antiserum raised against the nonglycosylated monomer of wheat germin. The cross-reaction between pine and wheat apoproteins was highly specific. An antiserum against the glycosylated pentameric germin-like protein (an oxalate oxidase) of barley cross-reacted with all three, as well as with several other glycosylated polypeptides.

Amino Acid Sequence↗
PubMed1995

A case study of female genital self-mutilation in schizophrenia.

A case of deliberate genital self-mutilation in a woman with familial schizophrenia is presented. Such behaviour, though well recognized in females with severe personality disorders, is extremely rare in female psychotics. The genital mutilation may be partially understood as a consequence of delusionally motivated action against a background of low self-esteem, premorbid body-image preoccupation, forced early sexual activity and hence profound ambivalence towards adult sexuality. Dealing with this constructively was hampered by a cognitive style characterized by impaired reasoning and reality testing. Tests of reasoning, judgement and reality testing showed deficits, and computed tomography revealed dilatation of the left frontal ventricular system. Both neuropsychological and psychodynamic factors appeared to be of relevance in this case.

Adult↗
PubMed1995

Stringent delineation of Pallister-Hall syndrome in two long surviving patients: importance of radiological anomalies of the hands.

We report two unrelated, long surviving patients (2 and 17 years) with syndromal hypothalamic hamartoblastoma. Both showed mild facial dysmorphism (downward slanted palpebral fissures, ptosis, microretrognathia), cleft epiglottis, and developmental delay. The younger child had stenosis of the pulmonary arteries, complex urogenital malformations, and anal atresia. In the oldest patient, the hamartoma caused precocious puberty of the central type, combined with complete hGH deficiency. Both patients showed bony anomalies of the extremities: variable proximal synostosis between central (2nd to 4th) metacarpals or intercalary polydactyly with generalised brachydactyly, severe brachytelephalangism, syndactyly, and nail hypoplasia. Together with the absence of anomalies of cholesterol metabolism, a combination of oral frenula, laryngeal malformations, digestive abnormalities, intercalary polysyndactyly, generalised brachytelephalangism, and nail hypoplasia should allow the delineation of Pallister-Hall syndrome, even when a CNS tumour is absent. The radiological abnormalities are helpful in differentiating Pallister-Hall syndrome from the other syndromes in which hypothalamic hamartoblastoma is observed. This is of major importance for genetic counselling, since Pallister-Hall syndrome may be a dominantly inherited disorder, thus contrasting with most of the other disorders with the CAVE phenotype, which are recessively inherited.

Abnormalities, Multiple↗
PubMed1995

Cognitive functioning and magnetic resonance imaging in chronic fatigue.

BACKGROUND: This study examines whether cognitive dysfunction in chronic fatigue may be accounted for by depression and anxiety or is due to brain pathology evident on magnetic resonance imaging (MRI). METHOD: Twenty-six subjects with chronic fatigue, with and without coexisting depression, and 18 age-matched normal controls were recruited from primary care following a presumed viral illness six months previously. Comparison was made with 13 psychiatric controls with depressive illness on standardised cognitive tests. MRI determined the presence of cerebral white-matter lesions. RESULTS: No substantial differences in performance were shown between subjects with chronic fatigue, most of whom met the criteria for chronic fatigue syndrome, and controls. Subjective cognitive dysfunction increased with psychopathology. White-matter lesions were found in a minority from all groups. Improvement in fatigue and depression coincided with improved performance on cognitive measures. CONCLUSIONS: Subjective complaints of cognitive impairment are a prominent feature of chronic fatigue, but objective cognitive and MRI abnormalities are not. Such complaints probably reflect psychopathology rather than a post-viral process.

Adolescent↗
PubMed1995

Insight and psychotic illness. Cross-sectional and longitudinal associations.

BACKGROUND: Insight has recently re-emerged as an important aspect of psychopathology amenable to empirical study. We sought to examine the relationship between various aspects of insight into illness and clinical, sociodemographic and neuropsychological variables. METHOD: From an inner-London catchment area population, 150 in-patients with recent onset of psychosis were assessed on a variety of measures, including the Present State Examination (PSE). Subjects were followed up for a mean of four years and reassessed. RESULTS: High IQ was associated with better insight as rated on the PSE, while gender, ethnicity and a diagnosis of schizophrenia appeared to be unrelated. At follow-up, similar associations were found, as well as correlations with attitudes to treatment and a more elaborate measure of insight. Cerebral ventricular enlargement and tests of frontal lobe function did not correlate with insight, but there was a curious, strong association with left-handedness at both assessment points. Initial insight correlated significantly but weakly with insight at follow-up. CONCLUSIONS: The assessment of insight in psychosis has concurrent validity and is a distinct aspect of psychotic phenomenology. It may, in part, have a neuropsychological basis.

Adolescent↗
PubMed1994

Autosomal dominant Muckle-Wells syndrome associated with cystinuria, ichthyosis, and aphthosis in a four-generation family.

Muckle-Wells syndrome is a rare autosomal dominant disorder characterized by chronic recurrent urticaria, periodic arthritis, sensorineural deafness, general signs of inflammation, and secondary amyloidosis (AA type). We report on a 4-generation family with 7 persons sharing various signs of this syndrome associated with bipolar aphthosis in 5 cases and cystinuria in one. Two other relatives in the family had ichthyosis.

Adolescent↗
PubMed1994

Predictors of chronic "postviral" fatigue.

We set out to determine the relation between a general practitioner (GP) diagnosis of viral illness and development of chronic fatigue 6 months later. 618 subjects who attended GPs clinics in London, south, and southwest England and who received a diagnosis of viral illness were followed prospectively and fatigue was assessed by questionnaire after 6 months. At presentation, GPs recorded fatigue in 62.6% of subjects, usually since the onset of symptoms. 502 (81.2%) subjects completed the 6-month questionnaire, of whom 88 (17.5%) met criteria for chronic fatigue and 65 (12.9%) had no reported fatigue before the viral illness. Compared with a similar group of non-postviral GP attenders, the risk ratio for chronic fatigue in the present cohort was 1.45 (95% CI 1.14-2.04). Infective symptoms did not predict fatigue 6 months later. Psychiatric morbidity, belief in vulnerability to viruses, and attributional style at initial presentation were all associated with self-designated postviral fatigue. Logistic regression showed that somatic attributional style, less definite diagnosis by the GP, and sick certification were the only significant predictors of chronic fatigue after viral infection when other factors were controlled for. Chronic severe fatigue 6 months after GP-diagnosed viral illness is related to symptom-attributional style and doctor behaviour, rather than to features of the viral illness. Some subjects with apparent postviral fatigue had complained of tiredness before their presentation with a viral illness.

Adult↗
PubMed1994

Genetic heterogeneity of Usher syndrome type 1 in French families.

Usher syndrome type 1 (US1) is an autosomal recessive disease characterized by profound congenital hearing impairment with unintelligible speech, early retinitis pigmentosa, and constant vestibular dysfunction. Three localizations have been described in US1: USH1A, 14q32; USH1B, 11q13.5; and USH1C, 11p15. Studying a series of 33 affected individuals belonging to 20 US1 pedigrees of French ancestry, we found that none of the three localizations accounted for all US1 families in our series (Zmax = 1.48 at theta = 0.10; Zmax = 1.45 at theta = 0.10; and Zmax = 0.36 at theta = 0.20 for probes MLJ14, Zd5, and Mfd58, respectively, at loci D14S13, D11S527, and D11S419, respectively). However, when our sample was split into two groups according to the geographic origin of the probands' grandparents, we were able to confirm the presence of a gene for US1 on chromosome 14q32 (USH1A) in 9 families originating from the Poitou region in Western France (Department of Deux-Sèvres; Zmax = 4.46 at theta = 0 for probe MLJ14 at the D14S13 locus, Morton likelihood ratio test, P < 0.01). Moreover, we refined the genetic mapping of USH1A by showing that the disease gene maps to the D14S13 locus, within the genetic interval defined by loci D14S78 and D14S250 (location score in log base 10 = 4.90). Consistent with this, nonsignificant lod score values for linkage to either USH1B or USH1C were found in this group.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosomes, Human, Pair 11↗
PubMed1994

Tear of the biceps femoris tendon.

The clinical and operative findings of an isolated rupture of the biceps femoris tendon are described. The immediate suture and the initial postoperative treatment with a knee brace limiting extension to 20 degrees and flexion to 70 degrees resulted in a free range of motion and full activity of the biceps femoris.

Adult↗
PubMed1994

'Maybe it's a virus?': beliefs about viruses, symptom attributional style and psychological health.

A questionnaire concerning beliefs about viruses was devised and validated as part of a study investigating the relationship between such attitudes, symptom attributional style and psychological morbidity in 283 general practice attenders. It was found, contrary to expectation, that those who believed they were powerless in the face of viruses were more likely to have higher psychological distress and to blame physical symptoms on emotional and psychological factors. Age, sex and the presence of an infective illness exerted only minor effects. Such data are informative in testing hypotheses regarding the development of illnesses where there is a strong belief in a viral aetiology, but where psychological factors are present, such as the post-viral fatigue syndrome.

Adolescent↗
PubMed1994

Long segment and short segment familial Hirschsprung's disease: variable clinical expression at the RET locus.

Hirschsprung's disease (aganglionic megacolon, HSCR) is a frequent condition of unknown origin (1/5000 live births) resulting in intestinal obstruction in neonates and severe constipation in infants and adults. In the majority of cases (80%), the aganglionic tract involves the rectum and the sigmoid colon only (short segment HSCR), while in 20% of cases it extends toward the proximal end of the colon (long segment HSCR). In a previous study, we mapped a gene for long segment familial HSCR to the proximal long arm of chromosome 10 (10q11.2). Further linkage analyses in familial HSCR have suggested tight linkage of the disease gene to the RET protoncogene mapped to chromosome 10q11.2. Recently, nonsense and missense mutations of RET have been identified in HSCR patients. However, the question of whether mutations of the RET gene account for both long segment and short segment familial HSCR remained unanswered. We have performed genetic linkage analyses in 11 long segment HSCR families and eight short segment HSCR families using microsatellite DNA markers of chromosome 10q. In both anatomical forms, tight pairwise linkage with no recombinant events was observed between the RET proto-oncogene locus and the disease locus (Zmax = 2.16 and Zmax = 5.38 for short segment and long segment HSCR respectively at 0 = 0%) Multipoint linkage analyses performed in the two groups showed that the maximum likelihood estimate was at the RET locus. Moreover, we show that point mutations of the RET proto-oncogene occur either in long segment or in short segment HSCR families and we provide evidence for incomplete penetrance of the disease causing mutation. These data suggest that the two anatomical forms of familial HSCR, which have been separated on the basis of clinical and genetic criteria, may be regarded as the variable clinical expression of mutations at the RET locus.

Chromosome Mapping↗
PubMed1994

[Epidemiologic study of chronic fatigue in primary care (general practice)].

The results of a cross sectional study of fatigue in two large samples of patients attending primary care physicians are reported. The level of complaint of fatigue was higher in the prospective sample, which consisted of patients who had been diagnosed as suffering from a viral infection six months earlier. Duration and frequency of experience of fatigue correlated with severity in both samples. Severity, duration and frequency were continuously distributed in these populations. Attribution of fatigue in these two samples was mixed: social stresses, current physical illness and psychological problems all being offered as explanations. 11% of the cross sectional sample and 17% of the prospective sample met study operational criteria for a possible chronic fatigue state. These patients were assessed in greater detail. The majority had a diagnosable psychiatric disorder, predominantly depression. Physical illnesses were not adequate to explain these fatigue states. These studies in primary care do not support a clinical entity of a "chronic fatigue syndrome". Some patients in primary care settings have complaints of fatigue that are both disabling and long lasting, but they do not form a distinct group although the majority are likely however to be suffering from a concurrent psychiatric disorder. In contrast to similar patients with chronic fatigue syndromes attending hospital clinics, primary care patients with complaints of fatigue are much more varied in their ideas of causation with considerable less evidence of disease conviction.

Adult↗
PubMed1994

A randomized, placebo-controlled, blind anti-AIDS clinical trial: safety and immunogenicity of a specific anti-IFN alpha immunization.

HIV-induced cytokine dysregulation, including overproduction of the antiproliferative and cytolytic IFN alpha cytokine, represents a major component of the immune disorders characterizing AIDS. To block the overproduction of IFN alpha we designed an AIDS vaccine combination which included both an anti-HIV and/or an anti-IFN alpha immunization. The safety and immunogenicity of this multicomponent vaccine were tested in mice, Cercopithecus, two HIV noninfected individuals, and six HIV-1 seropositive immunocompromised patients enrolled in a 1-year open clinical trial. We now report the result of a 9-month short-term randomized, blind, placebo-controlled clinical trial (Phase I/II) performed in HIV-1 patients (22 individuals) to confirm safety/tolerance of the anti-IFN alpha vaccine and its immunogenicity and to evaluate whether the complex vaccine initially used could be simplified by removal of HIV component(s). Three groups of patients received inactivated IFN alpha (i-IFN alpha) associated with the immunomodulator P40 with HIV-1 antigens (groups B and C) or without (group A), and one group (D) was placebo. The clinical follow-up documented among those receiving i-IFN-alpha showed that none developed AIDS and/or required antiretroviral chemotherapy. Viral load did not increase and CD4 cell count as well as cell-mediated immunity (CMI) stabilized or even significantly increased in group A. Immunogenicity of the preparations was determined by a positive delayed-type hypersensitivity (DTH) reaction to i-IFN alpha and the presence of serum antibodies to i-IFN alpha and to HIV-1 peptides, occurring only in treated patients. As previously planned, based on these safety data, the trial has been extended for an additional year and all patients were switched to protocol A (i-IFN alpha+P40). This second period of the trial, now open and ongoing, should allow us to evaluate further the innocuity of the i-IFN alpha preparation and whether anti-IFN alpha vaccine could provide a long-lasting CD4 cell count as well as CMI stabilization.

AIDS Vaccines↗
PubMed1994

Quantitative assessment of the visibility of unmyelinated corneal nerves in leprosy.

Unmyelinated corneal nerves were counted in 383 leprosy patients whose eyes looked normal on clinical examination and in an equal number of healthy controls. Visibility of these nerves was decreased significantly (p < 0.01) in the nasal half of the cornea in both patients and controls. There was a significant (p < 0.01) inverse correlation between age and the visibility of these nerves in patients and controls. There was a significant (p < 0.05) reduction in the visibility of these nerves as the spectrum of the disease moved from the tuberculoid to the lepromatous pole. There was no significant correlation between visibility of these nerves and the smear positivity of the patient. Neither did duration of the disease nor the duration of antileprosy treatment alter the visibility of these nerves significantly. Overall, there was a reduction in the visibility of these nerves in patients who had had leprosy reactions.

Adult↗