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Biomedical subjects

N N Singh

Publications and source records attributed to N N Singh.

At least 19 recordsLinked to original sources
PubMed2001

Interaction of a group II intron ribonucleoprotein endonuclease with its DNA target site investigated by DNA footprinting and modification interference.

Group II intron mobility occurs by a target DNA-primed reverse transcription mechanism in which the intron RNA reverse splices directly into one strand of a double-stranded DNA target site, while the intron-encoded protein cleaves the opposite strand and uses it as a primer to reverse transcribe the inserted intron RNA. The group II intron endonuclease, which mediates this process, is an RNP particle that contains the intron-encoded protein and the excised intron RNA and uses both cooperatively to recognize DNA target sequences. Here, we analyzed the interaction of the Lactococcus lactis Ll.LtrB group II intron endonuclease with its DNA target site by DNA footprinting and modification-interference approaches. In agreement with previous mutagenesis experiments showing a relatively large target site, DNase I protection extends from position -25 to +19 from the intron-insertion site on the top strand and from -28 to +16 on the bottom strand. Our results suggest that the protein first recognizes a small number of specific bases in the distal 5'-exon region of the DNA target site via major-groove interactions. These base interactions together with additional phosphodiester-backbone interactions along one face of the helix promote DNA unwinding, enabling the intron RNA to base-pair to DNA top-strand positions -12 to +3 for reverse splicing. Notably, DNA unwinding extends to at least position +6, somewhat beyond the region that base-pairs with the intron RNA, but is not dependent on interaction of the conserved endonuclease domain with the 3' exon. Bottom-strand cleavage occurs after reverse splicing and requires recognition of a small number of additional bases in the 3' exon, the most critical being T+5 in the now single-stranded downstream region of the target site. Our results provide the first detailed view of the interaction of a group II intron endonuclease with its DNA target site.

Adenine↗
PubMed1999

Direct service staff and their perceptions of psychotropic medication in non-institutional settings for people with intellectual disability.

Previous studies have surveyed a variety of service providers in school and institutional settings, and reported a pervasive lack of education and training with regard to the use of psychotropic medication in people with intellectual disability. Because an increasing number of people with intellectual disability are living in the community and since many of these people receive psychotropic medications, the present study extended research in this area by surveying direct service staff to determine their perceptions, knowledge and opinions with regard to the use of psychotropic medication in non-institutional settings for individuals with developmental disabilities. Consistent with the findings of previous studies, a majority of the 334 respondents in the present study reported that they had not received adequate training in the area of drug treatment The knowledge and skills deficits of direct service staff appear to represent a significant barrier to the appropriate monitoring and management of pharmacotherapy for individuals with intellectual disability. Therefore, a systematic training programme to educate direct service staff about psychotropic medication needs to be designed, implemented and disseminated on a broad scale.

Attitude of Health Personnel↗
PubMed1999

Herpes simplex virus-1 encephalitis in eastern Uttar Pradesh.

OBJECTIVE: To study the proportion of HSV-1 encephalitis in acute viral encephalitis. METHODS: One hundred and five patients presenting with clinical diagnosis of acute viral encephalitis and with exclusion of other possible causes of acute inflammatory brain disease prevalent in the area by relevant laboratory investigations were included in the study. Ninety single CSF samples were tested for HSV-1 IgM antibodies by ELISA test supplied by Dia Medix Corporation, USA. CT Scan and EEG studies were carried out in 25 patients. RESULTS: Clinical and neuro investigational profile of patients suggested a low incidence of HSV-1 encephalitis in the study group. IgM antibodies were present in CSF sample of one patient only. CONCLUSION: HSV-1 encephalitis constitutes a very low proportion (1.1%) of acute viral encephalitis cases seen in Eastern Uttar Pradesh (India).

Encephalitis, Herpes Simplex↗
PubMed1998

Recognition of facial expressions of emotion by children with attention-deficit hyperactivity disorder.

Fifty children and adolescents were tested for their ability to recognize the 6 basic facial expressions of emotion depicted in Ekman and Friesen's normed photographs. Subjects were presented with sets of 6 photographs of faces, each portraying a different basic emotion, and stories portraying those emotions were read to them. After each story, the subject was asked to point to the photograph in the set that depicted the emotion described. Overall, the children correctly identified the emotions on 74% of the presentations. The highest level of accuracy in recognition was for happiness, followed by sadness, with fear being the emotional expression that was mistaken most often. When compared to studies of children in the general population, children with ADHD have deficits in their ability to accurately recognize facial expressions of emotion. These findings have important implications for the remediation of social skill deficits commonly seen in children with ADHD.

Adolescent↗
PubMed1998

Recognition of facial expressions of emotion by Chinese adults with mental retardation.

We compared the ability of Chinese adults with mental retardation and nonhandicapped Chinese children to recognize the six basic facial expressions of emotion. Each subject was told a story identifying an emotion, presented with an array of six photographs of basic facial expressions of emotion, and asked to point to the photograph that depicted the story's emotion. Results showed that the children were more accurate than the adults in recognizing facial expressions of emotion except happiness on which both groups achieved 100% accuracy. Surprise, fear, anger, and disgust were confused most often by both groups. Recognition proficiency was not significantly correlated with age in the children or with IQ in the adults. Our results partially replicated those reported in earlier studies with non-Chinese individuals with mental retardation and raised the possibility that there may be cultural influences on a person's ability to recognize facial expressions of emotion.

Adolescent↗
PubMed1997

Psychopharmacoepidemiology of mental retardation: 1966 to 1995.

We present a brief historical overview of the prevalence studies of psychotropic drugs in individuals with mental retardation that were published between 1966 and 1985, and a more comprehensive review of the prevalence studies from 1986 to 1995. During the 1966 to 1985 period, typical prevalence rates of drug treatments in institutions (children and adults analyzed together) were found to range from 30% to 40% for psychotropic drugs, 25% to 45% for anticonvulsants, and 50% to 70% for psychotropic and/or anticonvulsant drugs (i.e., psychotropics, anticonvulsants, or their combinations). In the community during the same period, prevalence rates in children were typically 2% to 7% for psychotropics, 12% to 31% for anticonvulsants, and 18% to 33% for psychotropic and/or anticonvulsant drugs. For adults in the community, prevalence rates ranged from 26% to 36% for psychotropics, 18% to 24% for anticonvulsants, and 36% to 48% for psychotropic and/or anticonvulsant drugs. In contrast, during the 1986 to 1995 period, typical prevalence rates in institutions ranged from 12% to 40% for psychotropics, 24% to 41% for anticonvulsants, and 44% to 60% for psychotropic and/or anticonvulsant drugs. In the same period, the prevalence rates in the community (for adults and children analyzed together) ranged from 19% to 29% for psychotropics, 18% to 23% for anticonvulsants, and 35% to 45% for psychotropic and/or anticonvulsant drugs. An analysis of the patterns of medication use showed that patient demographic, physical, social, behavioral, and psychiatric variables, as well as a number of staff variables, were correlated with use of pharmacotherapy in the entire population of individuals with mental retardation. A substantial number of individuals with mental retardation appeared to be prescribed psychotropic medications that may have been inappropriate for their diagnosis.

Adolescent↗
PubMed1997

Chronic toxicity of propoxur on carbohydrate, protein and serum electrolyte levels in catfish, Heteropneustes fossilis.

Alterations in the biochemical parameters of the catfish treated with low sublethal concentration (2.15 mg.L-1; 1/3 of 96 h LC50) of a carbamate pesticide-propoxur under static laboratory conditions for 10, 20 and 30 days were assayed. The fish elicited consistent hyperglycemia, concomitant with liver and muscle glycogenolysis, and hypoproteinemia in muscle and liver except 10 day post exposure to the pesticide, where hyperproteinemia was noticed in the liver. Throughout the exposure period the fish exhibited hyperphosphatemia. Hypocalcemia were recorded after 20 and 30 days, and serum magnesium level increased significantly only at 30 day exposure to the pesticide.

Animals↗
PubMed1997

Role of macrophages in experimental malaria: IV--Bioassay of silica in immunity against Plasmodium berghei infection.

Silica treated mice when challenged with Plasmodium berghei showed increase in duration of prepatent(PP) and survival period (SP) and median survival day(MSD) as compared with controls. Daily parasite density curve during the course of infection was similar to control. Response to the parasite challenge, however, was dependent on the dose of silica. No increase in SP at 0.7 mg and in PP at 35 mg (cumulative doses) dose was observed. A dose upto 5 mg per mouse before challenge resulted in protection of the animal. No mortality was recorded in mice which received silica alone (35 mg; 5 mg/day x 7 days). Death due to lethal P.berghei infection could be delayed or prevented by altering/reducing the functional activities of macrophages during the course of infection.

Animals↗
PubMed1996

Professionals' perceptions of psychotropic medication in residential facilities for individuals with mental retardation.

Professional staff in four state facilities for individuals with mental retardation were surveyed to determine their perceptions, knowledge and opinions regarding the use of psychotropic medication. A large majority of the 377 respondents indicated that the physicians in their facilities were primarily responsible for medication-related decisions. Under ideal conditions, however, all professional staff and parents were seen as having a greater influence in the decision-making process. Aggression, delusions and hallucinations, self-injury, other psychiatric disorders, and anxiety were rated as disorders most likely to result in medication therapy. Behaviour modification was viewed as a suitable alternative to drug treatment for acting out and aggression. The professionals indicated that behavioural observation was the most influential assessment technique in current usage, followed by global impressions and informal diaries. Over 80% of the respondents perceived their preservice and inservice training on issues related to the use of psychotropic medication to treat behaviour problems as inadequate, with 96% of them desiring continuing education. These findings were compared to data from similar studies of populations with other disabilities, and suggestions for modifications in the current decision-making processes related to the use of psychotropic medication in institutionalized individuals with mental retardation are discussed.

Adolescent↗
PubMed1994

Clinical effects of buspirone on intractable self-injury in adults with mental retardation.

OBJECTIVE: The efficacy of buspirone in controlling self-injurious behavior was examined in five individuals with mental retardation. Buspirone was used alone in two individuals and as an adjunct to thioridazine in the other three. METHOD: Standard behavioral observation methods were used to collect data on the number of self-injurious responses of the individuals during baseline and several doses of buspirone in an open trial. RESULTS: When compared with baseline levels, all five individuals showed some response to buspirone, with reductions in self-injury ranging from 13% to 72%, depending on the dose. The most effective dose of buspirone was 30 mg/day for three individuals and 52.5 mg/day for the other two. These individuals were maintained for 6 to 33 weeks on their most effective dose. Coexistent symptoms of anxiety did not predict a favorable response to buspirone therapy. CONCLUSIONS: Buspirone showed a mixed but generally favorable response in controlling intractable self-injury in this and four previous studies reporting similar cases. However, the drug should not be endorsed as a proved treatment for self-injury until similar results have been obtained from well-controlled studies of its efficacy.

Adult↗
PubMed1993

Fluoxetine treatment of severe self-injury in young adults with mental retardation.

Dysfunction of the serotonergic system has been implicated in the development and maintenance of self-injury in some persons with mental retardation. Several preliminary reports have suggested that fluoxetine, a drug that blocks the reuptake of serotonin, may decrease self-injury in these individuals. Of the 44 cases of self-injury treated with fluoxetine and previously reported in the literature, 42 demonstrated a beneficial response to the drug. We report four additional cases of adults with mental retardation whose self-injury was treated with fluoxetine. Each of these individuals benefited from fluoxetine to some extent, with average decreases in self-injury ranging from 20% to 88% when compared with baseline levels. These findings, combined with those from previously published case studies, emphasize the need for well-controlled studies to more adequately assess the effects of fluoxetine on self-injury.

Adult↗
PubMed1993

Factor structure of the Motivation Assessment Scale.

The Motivation Assessment Scale (MAS) was developed to provide clinical information on four hypothesized functions that may control problem behaviour in persons with developmental disabilities. The original four-factor structure of the MAS was based on face validity, with the items being grouped in terms of each of the hypothesized functions. Validation of the scale was provided in terms of correlations between teacher ratings of eight children on the MAS and ranking of the controlling variables from functional analogue tests. In this study, staff in residential facilities rated 60 residents and teachers in schools rated 96 students on the MAS. The target behaviour rated for both samples was self-injury, with the institutional sample engaging in the behaviour more than 15 times an hour and the school sample, less than 15 times an hour. The results of factor analyses, with varimax rotation, provided a conceptually meaningful factor structure with the institutional sample, but not with the school sample. The 16 MAS items resolved into four factors that were conceptually related to four conditions that may maintain problem behaviour (i.e. sensory, escape, attention and tangible). The results suggested that the original MAS has a robust factor structure and may be clinically useful in predicting the controlling functions of problem behaviours, if the target behaviours occur at a rate no less than 15 responses per hour.

Adult↗
PubMed1993

Self-mutilation.

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Behavior Therapy↗
PubMed1993

Role of macrophages in experimental malaria: I. Development of immunobioassay indicators.

The role of macrophages in immunogenic mechanisms of malaria was studied. The first part of the study aimed at development of indicators for assessing immunobioassay. Accordingly, data on the natural course of lethal Plasmodium berghei infection in mice were collected, and baseline estimates of a set of indicators were made. The indicators along with their estimated means are: prepatent period (PP), 2.57 +/- 0.06 days; survival period (SP), 17.63 +/- 0.29 days; median survival day (MSD), 17.20 days; and parasite density 24 h before death (K), 3582.6 infected RBC/10(4)RBCs. The probable role of immunogenic mechanisms judged indirectly by course of parasitaemia in different phases is discussed.

Animals↗
PubMed1992

A study of the homeostatic level of stereotypy and other motor movements of persons with mental handicaps.

Stereotypy is one of the most common behaviours demonstrated by persons with mental handicaps. As such, it has generated a number of theories concerning its origin or maintenance. One of these theories, the homeostatic one, suggests that some persons engage in stereotypies and other motor behaviours in order to maintain a relatively constant level of responding. If this was indeed true, the fact would have important implications for treatment, i.e. those persons who varied rates of both stereotypy and other movements but retained an overall level of motoric responding would seem to be those for whom procedures like the differential reinforcement of incompatible behaviour would be highly appropriate. The purpose of this paper was to determine whether some people do engage in constant levels of responding, and it did so by collecting data on stereotypy and other motor movements of 12 persons with retardation. Collected throughout the school day for 5 consecutive days on micro-computers, the data showed (1) that the stereotypic responding of four subjects was extraordinarily consistent, with the most deviant day's total being only 15 or 16% from the mean of the 5 days, (2) that other motor movements were inconsistent for all but one subject, but (3) that total movement (i.e. stereotypy plus other motor movements) was very high and was consistent for most subjects. The data were discussed in terms of assessing baselines for subjects for whom reinforcing adaptive motor movements would seem an appropriate means for reducing stereotypic responding.

Adolescent↗