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Biomedical subjects

A Parekh

Publications and source records attributed to A Parekh.

At least 19 recordsLinked to original sources
PubMed2003

Abnormal cortex-muscle interactions in subjects with X-linked Kallmann's syndrome and mirror movements.

X-linked Kallmann's (XKS) subjects, who display mirror movements, have abnormal corticospinal tracts which innervate motoneurons of the left and right distal muscles of the upper limb. The size of the abnormal ipsilateral projection is variable. We have used coherence and cumulant analysis between EEG and first dorsal interosseous muscle (1DI) EMG to explore mechanisms underlying mirror movements in three XKS subjects. Results are compared with those of three normal subjects. We argue that significant coherence is functionally relevant when associated with a negative cumulant at an appropriate lag. Given this, normal subjects showed coherence at approximately 22 Hz between the EEG recorded over the sensori-motor cortex contralateral to the voluntarily moved hand and the 1DI EMG of this hand. No significant coherence was seen between 1DI EMG and the sensori-motor cortex ipsilateral to the muscle activity. In contrast, two of the XKS subjects (K2 and K4) had significant coherence at 22 Hz, together with a negative cumulant at an appropriate lag, between the ipsilateral cortical EEG and the 1DI EMG of the voluntarily activated hand. This implies that activity in the abnormal ipsilateral corticospinal projection can contribute to the voluntary drive. For these two subjects, the ipsilateral corticospinal projection was greater than the contralateral projection, as revealed using magnetic brain stimulation. In one of these subjects, K4, significant 22 Hz coherence and negative cumulant was also seen between the EMG of the voluntarily activated hand and the cortex contralateral to this hand. In the third subject, K4a, coherence and negative cumulant was detected between the EMG of the voluntary side and the cortical activity contralateral to this hand. The contralateral cortico spinal projection of this subject was greater than the ipsilateral projection. Regarding the mirroring hand of the XKS subjects, coherence (with negative cumulant at an appropriate lag) was seen in all three subjects between the EMG recorded from the mirroring hand and cortical EEG ipsilateral to this hand. This provides evidence that activity in the aberrant ipsilateral projection is involved in producing the drive that results in mirror movements. In one subject, K4, coherence and negative cumulant was also seen between the EMG of the mirroring hand and motor cortical activity contralateral to this hand. Thus, in this subject, activity in the corticospinal projection contralateral to the mirroring hand also contributed to the mirror movements. In conclusion, this study has provided further evidence that the 22 Hz coherence seen between EEG and EMG is dependent upon corticospinal activity and has furthered our understanding of mechanisms underlying mirror movements.

Adult↗
PubMed2001

Efficacy of a mixed amphetamine salts compound in adults with attention-deficit/hyperactivity disorder.

BACKGROUND: We report on a controlled trial of a mixed amphetamine salts compound (Adderall, dextroamphetamine sulfate, dextro-, levoamphetamine sulfate, dextroamphetamine aspartate, levoamphetamine aspartate, and dextroamphetamine saccharate) in the treatment of adult attention-deficit/hyperactivity disorder (ADHD). METHODS: This was a 7-week, randomized, double-blind, placebo-controlled, crossover study of Adderall in 27 well-characterized adults satisfying full DSM-IV criteria for ADHD of childhood onset and persistent symptoms into adulthood. Medication was titrated up to 30 mg twice a day. Outcome measures included the ADHD Rating Scale and the Clinical Global Impression Score. Comorbid psychiatric disorders were assessed to test for potential effects on treatment outcome. RESULTS: Treatment with Adderall at an average oral dose of 54 mg (administered in 2 daily doses) was effective and well tolerated. Drug-specific improvement in ADHD symptoms was highly significant overall (42% decrease on the ADHD Rating Scale, P<.001), and sufficiently robust to be detectable in a parallel groups comparison restricted to the first 3 weeks of the protocol (P<.001). The percentage of subjects who improved (reduction in the ADHD rating scale of > or =30%) was significantly higher with Adderall treatment than with a placebo (70% vs 7%; P =.001). CONCLUSIONS: Adderall was effective and well tolerated in the short-term treatment of adults with ADHD. More work is needed to evaluate the long-term effects of Adderall, or other amphetamine compounds, in the treatment of adults with ADHD.

Adult↗
PubMed2001

Emergency contraception in South Africa: knowledge, attitudes, and use among public sector primary healthcare clients.

To determine knowledge of, attitudes toward, and use of emergency contraception (EC), interviews were held with 1068 clients of 89 public sector primary healthcare facilities in two urban and two rural areas of South Africa. Only 22.8% of the clients had heard of EC. Awareness was significantly lower in the most rural area and among older, less educated women. Knowledge of EC was superficial, with 47.1% unsure of the appropriate interval between unprotected intercourse and starting EC and 56.6% not knowing whether it was available at the clinic. Few (9.1%) of those who knew of EC had used it. After explaining EC, attitudes toward its use were found to be positive, with 90.3% indicating that they would use it if needed. Awareness was lower than in developed countries, but higher than in other developing countries. Findings indicate that if women know of EC, where to get it, and how soon to take it, they would use it if needed.

Adolescent↗
PubMed2001

A controlled clinical trial of bupropion for attention deficit hyperactivity disorder in adults.

OBJECTIVE: Despite the increasing recognition of attention deficit hyperactivity disorder (ADHD) in adults, there is a paucity of controlled pharmacological trials demonstrating the effectiveness of compounds used in treatment, particularly nonstimulants. The authors report results from a controlled investigation to determine the anti-ADHD efficacy of bupropion in adult patients with DSM-IV ADHD. METHOD: This was a double-blind, placebo-controlled, randomized, parallel, 6-week trial comparing patients receiving sustained-release bupropion (up to 200 mg b.i.d.) (N=21) to patients receiving placebo (N=19). The authors used standardized structured psychiatric instruments for diagnosis of ADHD. To measure improvement, they used separate assessments of ADHD, depression, and anxiety symptoms at baseline and each weekly visit. RESULTS: Of the 40 subjects (55% male) enrolled in the study, 38 completed the study. Bupropion treatment was associated with a significant change in ADHD symptoms at the week-6 endpoint (42% reduction), which exceeded the effects of placebo (24% reduction). In analyses using a cutoff of 30% or better reduction to denote response, 76% of the subjects receiving bupropion improved, compared to 37% of the subjects receiving placebo. Similarly, in analyses using Clinical Global Impression scale scores, 52% of the subjects receiving bupropion reported being "much improved" to "very improved," compared to 11% of the subjects receiving placebo. CONCLUSIONS: These results indicate a clinically and statistically significant effect of bupropion in improving ADHD in adults. The results suggest a therapeutic role for bupropion in the armamentarium of agents for ADHD in adults, while further validating the continuity of pharmacological responsivity of ADHD across the lifespan.

Adult↗
PubMed2001

Limits of 80%-125% for AUC and 70%-143% for Cmax. What is the impact on bioequivalence studies?

OBJECTIVE: The US Food and Drug Administration (FDA) currently uses bioequivalence (BE) limits for fasting BE studies that are based on the 90% confidence interval for the ratio of difference of the test and reference products Cmax and AUC falling within 80% to 125%. The FDA has also proposed that BE limits be used similarly for AUC and Cmax measurements from fed BE studies. In some cases, regulatory agencies have considered a wider BE limit for Cmax, because of the typically higher variability of Cmax compared to AUC. We investigated the consequences of changing from an 80%/ 125% limit for both pharmacokinetic measures to one that uses a limit of 80%/125% for AUC and 70%/143% for Cmax. METHODS: We computed the sample sizes required for BE studies using 80%/125% for AUC and 70%/143% for Cmax as BE limits. We also determined the range of the ratios of Cmax and AUC values in a study that could meet the 70%/143% and 80%/125% BE limits. RESULTS: The sample size for the study, in order to have adequate power with 80%/125% for AUC and 70%/143% for Cmax, will be determined primarily by the intrasubject variability of AUC, though with a substantial proportion of studies (about one third) still determined by the variability of Cmax. The ratio of mean Cmax values that can pass a wider 70%/143% BE limit could easily be as high as 128%. CONCLUSION: Without further scientific or clinical rationale, we find it difficult to justify widening the bioequivalence limit for Cmax to 70%/143% for either fasting or fed BE studies.

Area Under Curve↗
PubMed2000

Laparoscopic augmentation cystoplasty using the novel biomaterial Surgisis: small-intestinal submucosa.

BACKGROUND AND PURPOSE: Urinary bladder augmentation is indicated for diverse conditions, including neurogenic bladder, cancer resection, spinal cord injury, and congenital anomalies. The ideal cystoplasty material is yet to be described. Native gastrointestinal segments commonly used are limited by leakage and small-bowel obstruction, metabolic/nutritional abnormalities, calculi, and malignancy. This study assessed laparoscopic bladder augmentation with porcine small intestinal submucosa (SIS). MATERIALS AND METHODS: Five female pigs (<25 kg) were prepared for surgery under general anesthesia. After Veress needle insufflation, a main 10-mm trocar was placed in the midline for the laparoscope, with two lateral 10-mm ports added for operative instruments. The bladder dome was incised, and a patch of SIS was sewn into the bladder using running 2-0 Vicryl. Three animals served as technical studies. Two additional sows underwent long-term survival surgery: one undiverted and one diverted via a Stamey suprapubic catheter. RESULTS: There were no operative losses. The mean operative time was 140 minutes. The SIS graft held the sutures without tearing. Laparoscopic survey revealed no urine leaks at bladder closure. All five animals voided postoperatively. Urinary extravasation was evident in the three undiverted technique animals. In the other two sows, cystoscopy at 7 days showed intact suture lines without evidence of urinary extravasation and with normal vesicular volumes. Tissue growth was evident, but the graft margins were still discernible. CONCLUSIONS: Laparoscopic bladder augmentation was possible using SIS but at minimal volumes. There were no operative complications; however, the material was difficult to deploy and may benefit from application of an absorbable scaffold. Postoperative urinary drainage is necessary. Further studies will optimize the graft configuration for maximal augmentation.

Animals↗
PubMed2000

From policy to praxis--a framework for the delivery of district mental health care in KwaZulu-Natal.

This article provides a schema for the provision of mental health care at district level. A framework for service delivery was derived from research conducted by the Community Mental Health Programme (CMHP) into the development of aspects of a district mental health care system in a semi-rural community area in KwaZulu-Natal. Furthermore, information was drawn from interviews with key stakeholders, national and provincial policy documents as well as international experience in the implementation of community-based systems of mental health care.

Community Mental Health Services↗
PubMed1998

Prevalence of minor psychiatric disorders in an adult African rural community in South Africa.

BACKGROUND: This paper reports on a two-stage community-based epidemiological study of selected minor psychiatric disorders conducted on an adult African population in South Africa. METHODS: Using a modified random cluster sampling method, 354 adults were identified as the first-stage sample, with the SRQ-20 being used as a first-stage screen. Clinical interviews based on DSM-IV checklists for generalized anxiety disorder, major depression and dysthymia were administered as the second-stage criterion to 81 subjects from the sample. RESULTS: The weighted prevalence for generalised anxiety and depressive disorders was 23.9% (95% CI 15.1%-32.7%), comprising: generalized anxiety 3.7%, major depression 4.8%, dysthymia 7.3%, and major depression and dysthymia 8.2%. Statistically significant associations were found between caseness and age, marital status, employment, income and educational level. CONCLUSIONS: The results are discussed in relation to comparative local and international data as well as in the context of the current restructuring of the mental-health care system in South Africa from tertiary curative care to integrated primary mental-health care.

Adolescent↗
PubMed1998

Child abuse and neglect. Influences of qualitative research and clinical practice on child-care legislation and policy.

In an early paper, the authors presented the findings of a qualitative research study which applied the self-psychological and object relations theories to the social and interpersonal dynamics surrounding adolescent sexual offending. One of the findings of the study was that informal and formal social responses to detected offenders encouraged the rapid foreclosure of deviant, bad and dangerous social, interpersonal and sexual identity and therefore militated against therapeutic personality reconstruction. The current paper widens the scope of such observations to include the victim, as well as the offender, and examines the role of the therapist in mediating between intrapsychic and interpersonal priorities carried within the offense dynamics and socially and legally defined exigencies surrounding child abuse. The authors suggest that appropriate devolution of therapeutic agency can be devolved to patients through the concept of the twinship transference while at the same time attending to necessary psychiatric, medical, social and legal processes.

Child↗
PubMed1997

Adolescent sexual offenders: a self-psychological perspective.

Following a request for assistance in formulating a treatment philosophy for adolescent sexual offenders, a qualitative study of seven adolescent offenders was designed with a view to elaborating pre-offense, and post-offense dynamics. The point of departure was the hypothesis that sexual offending had relation to object relations. It was further hypothesized that offenders' object relations and self-development had been disfigured in childhood and adolescent development. The developmental theories of Mahler, Stern, Winnicott, and Kohut were reviewed in order to shed light on the connection between disfigured self-development and sexual offending. Mahler's work suggested that anomalies during the separation-individuation process were heavily implicated. Winnicott's thinking on transitional functioning in potential space and his employment of the concepts of the true self and false self were especially useful. These bodies of work were assimilated to Kohut's theory of self development in which three nuclear sectors of the self, namely, the grandiose-exhibitionistic sector, the idealizing-voyeuristic sector, and the twinship-alterego sector, gradually coalesce and cohere through the moderating influence of parental empathy with the child's developmental tasks. Where such empathy is unforthcoming, or when the normal parental functions are obliterated by traumatic experiences of abuse, unmoderated needs for exhibitionism and voyeurism continue through childhood, adolescence, and adulthood. Victims of sexual offending were hypothesized to perform functions of restoration and preservation of a chronically weak and threatened self. The sample's interview transcripts were qualitatively analyzed and aggregated. Analysis suggested that, indeed, offenses appeared to have been motivated to preserve a weakened sense of self and that the thoughts and perceptions surrounding the offenses resonated with expressions of problematic separation from parental objects. In addition, it was noted that in the post-offense period, offenders had become subject to close supervision, or proctoring, from both formal and informal systems. In close supervision, offenders tended to rapidly crystallize a foreclosed, negative, deviant sexual identity in defense of unmoderated narcissism. Other observations were that intrafamilial offending was consistent with enmeshment in the family, adjudication and apparent treatment readiness, while extrafamilial offending was consistent with exclusion from the family, no adjudication and resistance to treatment.

Adolescent↗
PubMed1992

Cloning and functional characterization of the rat stomach fundus serotonin receptor.

A DNA segment homologous to the third exons of the serotonin 1C and 2 receptor genes was isolated from a mouse genomic library. The positions of the introns flanking these exons were conserved in the three genes. To examine whether the new fragment was part of an active gene, we used a quantitative PCR protocol to analyse rat RNAs from different tissues and ages. The gene was expressed in stomach fundus at an abundance of 1 x 10(5) mRNA molecules. This tissue contracts in response to serotonin via a receptor that has previously resisted classification. We constructed a cDNA library from rat stomach fundus and isolated clones containing 2020 bp inserts with open reading frames of 465 amino acids comprising seven putative membrane-spanning regions. The protein was transiently expressed in COS cells and binding of serotonergic ligands to the membranes was analysed. The pharmacological profile resembled that described for the serotonin-stimulated contraction of the stomach fundus. After expression of this receptor in Xenopus oocytes, the application of serotonin triggered the typical chloride current which presumably results from the activation of phospholipase C. The coupling to this response system was less efficient than that of the 5-HT1C or 5-HT2 receptors.

Amino Acid Sequence↗
PubMed1988

A cohort study of alkaloidal cocaine ("crack") in pregnancy.

The recent dramatic increase in the use of alkaloidal cocaine ("crack") has led to concern about possible deleterious fetal effects associated with its use during pregnancy. Crack, which is not destroyed by heating, can be smoked, and delivers a large quantity of cocaine to the vascular bed of the lung, producing an effect similar to that from intravenous injection. To describe the association of crack use with pregnancy outcome, we conducted a retrospective matched cohort study of 55 women who admitted to the use of crack during pregnancy and 55 non-drug-using women who delivered during the same period. The groups were matched for age, parity, socioeconomic status, alcohol use, and presence or absence of prenatal care. A significantly larger number of women using crack delivered at 37 weeks or earlier (50.9 versus 16.4%; P = .001). Crack-exposed infants were 3.6 times more likely to have intrauterine growth retardation (P less than .006) and 2.8 times more likely to have a head circumference less than the tenth percentile for gestational age (P less than .007). Premature rupture of the membranes was 1.8 times more common in the crack group (P less than .03). Sixty percent of crack-using mothers received no prenatal care. Abnormal neurobehavioral symptoms were present in a minority of infants and were usually mild.

Adult↗
PubMed1986

Antidiuretic hormone response in children with bronchopulmonary dysplasia during episodes of acute respiratory distress.

We investigated the antidiuretic hormone (ADH) response in 12 infants with bronchopulmonary dysplasia during acute respiratory distress. All of the infants had hypoxemia with air-trapping in the chest at the time of admission to the hospital. None had documented infection. There was a dramatic increase in the plasma levels of ADH during acute respiratory distress, with a subsequent reduction of levels toward normal when the respiratory distress decreased to the preadmission well state. Three of 12 infants manifested hyponatremia at 24 hours after admission, with two of them exhibiting persistent hypertension for up to three days. The mechanism for elevated ADH levels is air-trapping in the chest, causing pulmonary hypovolemia and decreased left atrial filling and/or decreased transmural pressure of the left atrium.

Bronchopulmonary Dysplasia↗
PubMed1983

Neonatal methadone withdrawal. Effect of two treatment regimens.

Thirty-one infants exposed to methadone in utero who required pharmacologic treatment for withdrawal symptoms were randomly assigned to a paregoric or phenobarbital treatment group. Seven infants had symptoms too mild to require treatment. Respiratory rate, blood pH, PCO2, systolic BP, and serum thyroxine concentrations were measured on the 4th, 7th, and 14th days of life. Platelet counts were performed on the seventh and 14th days of life, and urinary catecholamine excretion was measured on the sixth day of life. Rates of weight gain were recorded during the second and third weeks of life. With the exception of a slightly higher blood PCO2 level in the phenobarbital-treated infants on day 7, no significant intergroup differences were observed in the treated infants. Paregoric-treated infants required a significantly longer period of treatment than phenobarbital-treated infants (22 v 17 days). This may have been due, at least in part, to the prolonged half-life and relatively high blood levels of phenobarbital present after cessation of therapy.

Blood Pressure↗
PubMed1981

Results of gastric neutralization with hourly antacids and cimetidine in 320 intubated patients with respiratory failure.

In a retrospective analysis massive upper gastrointestinal (GI) hemorrhage, defined as blood loss requiring more than two units of blood transfusion over a 24-hour period, occurred in 40 (9.5 percent) of 420 intubated, mechanically ventilated patients with respiratory failure, irrespective of the etiology of the respiratory failure. In a prospective study hourly antacid gastric neutralization, maintaining the gastric pH over 5, the incidence of massive gastric bleeding was reduced to 3 (1.4 percent) of 210 patients. In 110 additional patients, cimetidine, a histamine H2 receptor blocker, was used to prevent gastric acid secretion; 3 (2.7 percent) of 110 patients had massive upper GI bleeding; all three had solitary chronic pyloric ulcers. We conclude that gastric neutralization, either with hourly antacids or with cimetidine, is effective in reducing the incidence of massive gastric hemorrhage in intubated, mechanically ventilated patients during respiratory failure. We recommend the use of either in all intubated patients with respiratory failure. In addition, in 17 patients who had gastric bleeding at the time of transfer to the respiratory intensive care unit, gastric neutralization with hourly antacids in 14 patients and with cimetidine in three patients stopped the bleeding in all 17 patients within 24 to 48 hours.

Aged↗
PubMed1981

Intrauterine exposure to narcotics and cord blood prolactin concentrations.

Umbilical cord serum prolactin concentrations were determined in 17 full-term infants of mothers using narcotic agents during pregnancy and in 18 infants of similar birth weight and gestational age whose mothers did not use narcotics. The median value for the narcotic-exposed group was 266.6 ng/ml (range, 157.5 to 448.7 ng/ml); in the normal group the median was 193.7 ng/ml (range, 69.8 to 693.1 ng/ml). These differences were statistically significant (P less than .05). Although only full-term and borderline premature infants who were not appreciable risk for respiratory distress syndrome (RDS) were studied, it may be speculated that elevated prolactin blood levels in fetuses of addicted mothers may at least in part explain the reported decrease in the incidence of RDS in this group.

Birth Weight↗