Biomedical subjects

M A Richter

Publications and source records attributed to M A Richter.

At least 19 recordsLinked to original sources

PubMed2005

The serotonin-1Dbeta receptor gene and severity of obsessive-compulsive disorder in women with bulimia nervosa.

BACKGROUND: There is significant evidence that eating disorders have an important biological overlap with obsessive-compulsive disorder (OCD), though the specific mediators of this relationship remain unclear. Recent evidence suggests that the G861C polymorphism of the 5HT-1Dbeta receptor gene and the G allele in particular may play a role in OCD. We thus hypothesized that, among a heterogenous group of probands with bulimia nervosa (BN), this same G allele might predict the presence and/or severity of OCD pathology. METHODS: 165 consecutive female probands with BN were genotyped for the G861C polymorphism of the 5HT-1Dbeta receptor gene. Rates of full syndrome OCD, partial syndrome OCD and no OCD were compared across the three genotypic groups defined by this polymorphism. RESULTS: 45 out of 165 BN probands (27.3%) had either full or partial syndrome OCD. In the full sample, there was a significant difference in the distribution of the three diagnostic groups by genotype (chi2=10.07, df=4, p=.039). The G861C polymorphism did not strongly predict which probands had any vs. no OCD pathology. However, among the 45 probands with OCD symptoms, the G861C polymorphism did strongly differentiate full syndrome vs. partial syndrome OCD (chi2=9.26, df=2, p=.01; odds ratio for full syndrome OCD with GG genotype=7.69, 95% CI=1.45-40.9). DISCUSSION: In women with BN, the G861C polymorphism of the 5HT-1Dbeta gene does not appear to be associated with the generation of OCD symptoms; however, it might directly or indirectly be associated with a modulatory effect on syndrome severity in probands otherwise predisposed to OCD. While preliminary and in need of replication in other samples, this is the first association study to suggest how a particular gene might influence OCD pathology in an eating disorder population.

Adolescent↗

PubMed2002

Obsessive-compulsive disorder and the five-factor model of personality: distinction and overlap with major depressive disorder.

Research on individual differences in obsessive-compulsive disorder (OCD) has focused largely on analogue models with participants experiencing sub-clinical obsessions and/or compulsions. Few studies have examined the association between normal, dimensional personality traits and obsessive-compulsive symptomatology in a clinical sample. The purpose of this study was to examine personality differences in patients with a primary diagnosis of OCD (n = 98) or major depression (n = 98) using the domains and facets of the five-factor model of personality (FFM). Patients completed the self-report version of the Revised NEO Personality Inventory (NEO PI-R). When contrasted with community controls (Revised NEO Personality Inventory (NEO-PI-R) and NEO Five-Factor Inventory (NEO-FFI) professional manual, Psychological Assessment Resources, Odessa, FL, 1992), participants with OCD were found to differ across the domains (and facets) of neuroticism, extraversion, and conscientiousness and the facets of openness and agreeableness. Further, when compared to depressed participants, those with OCD were found to be more extraverted, agreeable, conscientious and less neurotic. With the exception of the conscientiousness domain (and facets), these significant differences were maintained even after controlling for depression severity. These results highlight the unique associations between trait domains and facets of the FFM and OCD.

Adult↗

PubMed2002

5HT1Dbeta Receptor gene implicated in the pathogenesis of Obsessive-Compulsive Disorder: further evidence from a family-based association study.

Obsessive-Compulsive Disorder (OCD) is a psychiatric condition with strong evidence for a genetic component and for the involvement of genes of the serotonin system. In a recent family-based association study we reported an association between the G allele of the G861C polymorphism of the 5HT1Dbeta receptor gene and OCD. The aim of the present study was to further investigate for the presence of linkage disequilibrium between each of two polymorphisms of the 5HT1Dbeta receptor gene and OCD in a larger sample of OCD families. In a total of 121 families the G861C and the T371G polymorphisms of the 5HT1Dbeta receptor gene were genotyped using standard protocols. The genotyping data were analyzed with a new extension of the Transmission Disequilibrium Test (FBAT). The phenotypes considered in the analyses were the diagnosis of OCD and two quantitative phenotypes related to the diagnosis and clinically relevant, ie, the age at onset and the severity of OCD symptoms. We confirmed the previously found preferential transmission of the G861 allele to the affected subjects (z = 2.262, P = 0.02). No significant association was found between the polymorphism and the quantitative phenotypes considered. These results represent a confirmation of our previous published study and thus, could have important implications for the role of the 5HT1Dbeta receptor gene in the pathogenesis and treatment of OCD. Further genetic investigations on this marker considering additional polymorphisms and other quantitative phenotypes related to OCD are warranted.

Family Health↗

PubMed2001

Is obsessive-compulsive disorder an autoimmune disease?

OBSESSIVE-COMPULSIVE DISORDER (OCD) IS A COMMON and debilitating neuropsychiatric disorder. Although it is widely believed to have a genetic basis, no specific genetic factors have been conclusively identified as yet, leading researchers to look for environmental risk factors that may interact with an underlying genetic susceptibility in affected individuals. Recently, there has been increasing interest in a possible link between streptococcal infections and the development of OCD and tic disorders in children. It has been suggested that OCD in some susceptible individuals may be caused by an autoimmune response to streptococcal infections, that is, a similar biological mechanism to that associated with Sydenham's chorea. The term "pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections" (PANDAS) has been used to describe a subset of children with abrupt onset or exacerbations of OCD or tics, or both, following streptococcal infections. Affected children have relatively early symptom onset, characteristic comorbid symptoms and subtle neurological dysfunction. Neuroimaging studies reveal increased basal ganglia volumes, and the proposed cause involves the cross-reaction of streptococcal antibodies with basal ganglia tissue. Vulnerability to developing PANDAS probably involves genetic factors, and elevated levels of D8/17 antibodies may represent a marker of susceptibility to PANDAS. Prophylactic antibiotic treatments have thus far not been shown to be helpful in preventing symptom exacerbations. Intravenous immunoglobulin therapy may be an effective treatment in selected individuals. Further understanding of the role of streptococcal infections in childhood-onset OCD will be important in determining alternative and effective strategies for treatment, early identification and prevention of this common and debilitating psychiatric disorder.

Adolescent↗

PubMed2001

Effects of acetylpromazine or morphine on urine production in halothane-anesthetized dogs.

OBJECTIVE: To assess the influence of preanesthetic administration of acetylpromazine or morphine and fluids on urine production, arginine vasopressin (AVP; previously known as antidiuretic hormone) concentrations, mean arterial blood pressure (MAP), plasma osmolality (Osm), PCV, and concentration of total solids (TS) during anesthesia and surgery in dogs. ANIMALS: 19 adult dogs. PROCEDURE: Concentration of AVP, indirect MAP, Osm, PCV, and concentration of TS were measured at 5 time points (before administration of acetylpromazine or morphine, after administration of those drugs, after induction of anesthesia, 1 hour after the start of surgery, and 2 hours after the start of surgery). Urine output and end-tidal halothane concentrations were measured 1 and 2 hours after the start of surgery. All dogs were administered lactated Ringer's solution (20 ml/kg of body weight/h, i.v.) during surgery. RESULTS: Compared with values for acetylpromazine, preoperative administration of morphine resulted in significantly lower urine output during the surgical period. Groups did not differ significantly for AVP concentration, Osm, MAP, and end-tidal halothane concentration; however, PCV and concentration of TS decreased over time in both groups and were lower in dogs given acetylpromazine. CONCLUSIONS AND CLINICAL RELEVANCE: Preanesthetic administration of morphine resulted in significantly lower urine output, compared with values after administration of acetylpromazine, which cannot be explained by differences in AVP concentration or MAP When urine output is used as a guide for determining rate for i.v. administration of fluids in the perioperative period, the type of preanesthetic agent used must be considered.

Acepromazine↗

PubMed2000

Association between homozygosity at the COMT gene locus and obsessive compulsive disorder.

A functional polymorphism in the coding region of the catechol O-methyltransferase (COMT) gene has been reported in previous studies to be associated with obsessive compulsive disorder (OCD), particularly in males [Karayiorgou et al., 1997, 1999]. Using a family-based population analysis, we attempted to replicate these findings in a group of 72 OCD patient/parent trios collected from Buffalo, New York, and Toronto, Canada. Analysis of allele and genotype frequencies using the haplotype relative risk (HRR) and transmission disequilibrium test (TDT) did not identify an association between a particular allele and OCD as had been previously reported. Furthermore, no evidence was found to support the findings of a gender-based association for COMT when the patients and the parents of the same gender were compared. However, our genotype results (n = 72) demonstrate a tendency for association between homozygosity at the COMT locus and OCD (homozygosity analysis: chi(2) = 5.66, P = 0.017; genotypic analysis: chi(2) = 5.78, P = 0.056). Although these findings do not replicate the previous reports, they do provide limited support to demonstrate a trend for homozygosity at the COMT locus in the OCD patients and, in turn, further implicate a potential role for COMT in the genetic etiology of OCD. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:721-724, 2000.

Alleles↗

PubMed2000

Is the 5-HT(1Dbeta) receptor gene implicated in the pathogenesis of obsessive-compulsive disorder?

OBJECTIVE: Obsessive-compulsive disorder (OCD) is a psychiatric condition for which strong evidence of a genetic component and serotonergic system involvement exists. Recent studies have shown that sumatriptan, a selective ligand of the serotonin (5-HT)(1Dbeta) autoreceptor, modifies OCD symptoms. The aim of this study was to investigate the presence of linkage disequilibrium between the 5-HT(1Dbeta) receptor gene, which has a variant caused by a silent G to C substitution at nucleotide 861 of the coding region, and OCD. METHOD: DNA was collected from 67 probands who met DSM-IV criteria for OCD and from their living parents or siblings. Transmission Disequilibrium Test/sib-Transmission Disequilibrium Test analyses were then conducted with the DNA data. RESULTS: Thirty-two families were informative for the analysis, which showed a preferential transmission of the G allele to the affected subjects. CONCLUSIONS: If the results are confirmed, there may be important implications for the 5-HT(1Dbeta) receptor gene in the pathogenesis and treatment of OCD.

Adult↗

PubMed2000

Effects of anesthesia, surgery, and intravenous administration of fluids on plasma antidiuretic hormone concentrations in healthy dogs.

OBJECTIVE: To evaluate effects of anesthesia, surgery, and intravenous administration of fluids on plasma concentrations of antidiuretic hormone (ADH), concentration of total solids (TS), PCV, arterial blood pressure (BP), plasma osmolality, and urine output in healthy dogs. ANIMALS: 22 healthy Beagles. PROCEDURE: 11 dogs did not receive fluids, and 11 received 20 ml of lactated Ringer's solution/kg of body weight/h. Plasma ADH adn TS concentrations, PCV, osmolality, and arterial BP were measured before anesthesia (T0) and after administration of preanesthetic agents (T1), induction of anesthesia (T2), and 1 and 2 hours of surgery (T3 and T4, respectively). Urine output was measured at T3 and T4. RESULTS: ADH concentrations increased at T1, T3, and T4, compared with concentrations at T0. Concentration of TS and PCV decreased at all times after administration of preanesthetic drugs. Plasma ADH concentration was less at T3 in dogs that received fluids, compared with those that did not. Blood pressure did not differ between groups, and osmolality did not increase > 1% from To value at any time. At T4, rate of urine production was less in dogs that did not receive fluids, compared with those that did. CONCLUSIONS AND CLINICAL RELEVANCE: Plasma ADH concentration increased and PCV and TS concentration decreased in response to anesthesia and surgery. Intravenous administration of fluids resulted in increased urine output but had no effect on ADH concentration or arterial BP. The causes and effects of increased plasma ADH concentrations may affect efficacious administration of fluids during the perioperative period in dogs.

Anesthesia↗

PubMed1999

Symptom structure in obsessive-compulsive disorder: a confirmatory factor-analytic study.

Although obsessive-compulsive disorder (OCD) has long been a unitary diagnosis, there is much recent interest in its potential heterogeneity, as manifested by symptom subgroups. This study evaluated existing models of symptom structure in a sample of 203 individuals with OCD. Using confirmatory factor analysis, we examined the ability of each model to account for two levels of data: a priori symptom groupings (second-order) and individual symptoms, identified by the Yale-Brown Obsessive Compulsive Scale symptom checklist. Four models were examined: a single-factor, a two-factor (i.e., obsessions and compulsions), and two multidimensional models, comprising three and four factors. Adequate fit was found solely for the four-factor model--specifying obsessions/checking, symmetry/ordering, contamination/cleaning, and hoarding--but only at the second-order level; it did not account for relationships among discrete symptoms. Parameter estimates showed within-factor heterogeneity, as well as overlap between factors, most notably the two representing checking and contamination-related symptoms. The implications of these findings are discussed. Results provide evidence for the multidimensionality of OCD symptoms, but suggest that a comprehensive model has yet to be identified. They also point to the inadequacy of groupings based solely upon overt behavioural similarities (e.g., 'checking'). Recommendations are made for future research.

Adult↗

PubMed1998

Investigation of dopamine system genes in obsessive-compulsive disorder.

Evidence from anatomical, pharmacological, and animal studies on the involvement of the dopamine system in obsessive-compulsive disorder (OCD) is mounting. This, along with evidence for a genetic diathesis provided by family and twin studies, prompted us to conduct genetic association studies of dopamine system genes in OCD. We genotyped OCD patients (n > 100) and matched controls for four loci: (1) a 40-base-pair repeat in the dopamine transporter gene; (2) the TaqIA polymorphism and the serine/cysteine variation in the D2 dopamine receptor gene; (3) an MscI polymorphism in the D3 dopamine receptor gene; and (4) a 48-base-pair repeat in the D4 dopamine receptor gene. Significant differences in allele frequencies were found between patients and controls for the D4 receptor gene, although replication is required with family-based controls before any conclusions can be entertained. This study represents the first comprehensive assessment of the roles of dopamine system genes in OCD.

Age of Onset↗

PubMed1998

Clinical features distinguishing patients with Tourette's syndrome and obsessive-compulsive disorder from patients with obsessive-compulsive disorder without tics.

OBJECTIVE: It is not clear whether obsessive-compulsive disorder (OCD) in the context of Tourette's syndrome (TS) is the same as that disorder found in patients with OCD alone. This study evaluated the severity and characteristics of the obsessive-compulsive symptoms in adult patients with OCD and TS compared to adult patients with OCD alone. METHOD: Thirteen subjects with both DSM-III-R TS and OCD and 13 subjects with OCD alone were recruited. Obsessive-compulsive severity was determined by using the Yale-Brown Obsessive Compulsive Scale. The Tourette Syndrome Association Unified Tic Rating Scale was administered to determine tic severity, and the adult version of the Attention Deficit and Hyperactivity Checklist was used to detect a history of childhood attention-deficit hyperactivity disorder (ADHD). RESULTS: Subjects with OCD alone had very few obsessions and compulsions that were not also experienced by subjects with both TS and OCD. In contrast, subjects with TS and OCD were significantly more likely to report obsessions involving nonviolent images, excessive concern with appearance, and need for symmetry. Touching, blinking or staring, and counting compulsions were also significantly more common in this group. Eight subjects with OCD and TS had a childhood history of ADHD, compared to none of the pure OCD subjects. CONCLUSION: There are subtle but definite differences in symptomatology of subjects with pure OCD compared to those with OCD and TS consistent with putative differences in pathophysiology between the 2 groups, i.e., abnormalities in the serotonergic system in OCD patients and serotonergic and dopaminergic abnormalities in those with OCD and TS. These observations may be consistent with genetic heterogeneity within both OCD and TS.

Adult↗

PubMed1997

Memory and confidence in memory judgements among individuals with obsessive compulsive disorder and non-clinical controls.

The present study investigated episodic memory functioning in: (1) obsessive compulsive disorder (OCD) patients with primarily checking symptoms (i.e. checkers); (2) OCD patients without checking symptoms (i.e. non-checkers); and (3) non-clinical control participants. On a measure of recall, all groups were statistically equivalent with respect to the proportion of words correctly recalled. Using a recognition measure, checkers were unimpaired in episodic memory, as compared to non-checkers and non-clinical controls. However, relative to the other groups, patients with checking symptoms showed decreased confidence in their correct and incorrect recognition memory judgements, according to their item-by-item self-report confidence ratings. When checkers correctly identified previously seen words, they were also slower to respond than were the other groups, supporting the view that they were less confident in their memory judgments relative to the other groups, which did not differ on this measure. The results of the present study suggest that OCD checking is not related to memory impairments per se but rather that checking in OCD is a symptom of decreased confidence in memory.

Adult↗

PubMed1997

Obsessive compulsive disorder, response to serotonin reuptake inhibitors and the serotonin transporter gene.

Obsessive compulsive disorder (OCD) is a common illness, characterized by anxiety-provoking thoughts and the need to perform rituals. OCD is most commonly treated with a class of pharmacological agents known as serotonin reuptake inhibitors (SRIs). SRIs block the reuptake of serotonin (5-HT) into the presynaptic neuron, a process mediated by the serotonin transporter (5-HTT). The successful use of SRIs in OCD has led to the hypothesis that 5-HTT may play a pivotal role in the pathogenesis of OCD. We decided to study this hypothesis from a genetic perspective, because family and twin studies suggest that there is a strong genetic component to OCD. In addition, the sequence of the gene for 5-HTT is available, and a 44-bp insertion/deletion polymorphism has been detected in the promoter region of the gene. There is evidence that this polymorphism alters expression of the transporter protein. We typed 72 OCD patients and 72 matched controls, and found no statistically significant difference between the two groups (chi 2 = 4.319, P = 0.115, 2 d.f.). We observed however a trend towards increased homozygosity in the patient group. We also rated (retrospectively) the patients' clinical responses to SRIs. No association was observed between these ratings and the promoter region polymorphism in the serotonin transporter gene. Given the pharmacological evidence favoring a role for 5-HTT in OCD and SRI response, further genetic evaluation of the serotonin transporter in OCD is indicated.

Adult↗

PubMed1996

The Tridimensional Personality Questionnaire in obsessive-compulsive disorder.

This study examined the Tridimensional Personality Questionnaire in 32 patients with obsessive-compulsive disorder. Scores on the Harm Avoidance (HA) dimension alone were found to distinguish the patient from normal volunteers. The impact of multiple anxiety disorders and of the specific lower-order HA trait of fear of uncertainty was also demonstrated.

Adult↗

PubMed1994

A comparison of three assessment instruments for obsessive-compulsive symptoms.

The psychometric characteristics and relationship among the Leyton Obsessional Inventory, Maudsley Obsessional-Compulsive Inventory, and Yale-Brown Obsessive-Compulsive Scale were examined in a sample of 30 obsessive-compulsive patients diagnosed using a structured interview. The majority of the subscales of the various measures were found to have good internal consistency across gender and the mean scores were similar to those reported in other studies. There were also moderate correlations between several of the measures and clinician ratings of depression. The results suggest that (1) gender differences should be further explored in future research (2) caution should be used when extrapolating the results of treatment studies that use different OCD measures, and (3) a measure of depression should always be included in OCD studies to control for the possible effects of depressed mood.

Adult↗

PubMed1993

Effects of subject velocity on force plate-measured ground reaction forces in healthy greyhounds at the trot.

Force plate gait analysis was used to study the effects of subject velocity on ground reaction forces. Seven adult Greyhounds were trotted at 3 distinct velocities: 1.5 to 1.8 m/s, 2.1 to 2.4 m/s, and 2.7 to 3.0 m/s. Forelimb and hind limb peak vertical forces increased with increase in velocity (P < 0.05). Forelimb and hind limb vertical impulses decreased as velocity increased (P < 0.05). Significant variations were not observed for craniocaudal or mediolateral peak forces or impulses. It was concluded that velocity significantly (P < 0.05) influenced ground reaction forces and impulses, and must be controlled in experimental design.

Analysis of Variance↗

PubMed1992

Adverse cutaneous reactions associated with fluoxetine strategy for reintroduction of this drug in selected patients.

Four patients treated with fluoxetine alone developed generalized urticaria. One also suffered polyarthritis. These reactions subsided when fluoxetine was stopped. After 6-12 months, because of progressive psychiatric problems, fluoxetine was reintroduced using a desensitization protocol. In each case this was well tolerated, and fluoxetine has been continued without adverse affects for 3-10 months.

Adult↗

PubMed1992

Analgesia and behavioral responses of dogs given oxymorphone-acepromazine and meperidine-acepromazine after methoxyflurane and halothane anesthesia.

This study was designed to test analgesia, duration, and cardiovascular changes induced by meperidine (MEP) and oxymorphone (OXY) following methoxyflurane (MOF) and halothane (HAL) anesthesia. Eight healthy dogs were given atropine and acepromazine, and anesthesia was induced with thiamylal and maintained with 1.5 minimal alveolar concentration of MOF or HAL for 1 hour during controlled ventilation. Eight treatments were given with each anesthetic: 3 with MEP (0.5, 1.0, and 2.0 mg/kg, IV), 3 with oxymorphone (OXY; 0.05, 0.1, and 0.2 mg/kg, IV), and 2 placebos with sterile water. Test drugs were given at the end of anesthesia when early signs of recovery were evident. Minimal threshold stimulus/response nociception was assessed by use of an inflatable soft plastic colonic balloon. Blood pressures and pulse rate were measured with a noninvasive monitor. Meperidine and OXY were found to be effective analgesics and could be reversed with naloxone. Intravenous administration of 2.0 mg of MEP/kg provided analgesia for 36 +/- 6 minutes and 39 +/- 15 minutes after MOF and HAL, respectively. In contrast, OXY was effective at all 3 doses with effects of IV administration of 0.2 mg of OXY/kg lasting 154 +/- 13 minutes and 152 +/- 12 minutes, after MOF and HAL, respectively. Analgesia could not be demonstrated after anesthesia for acepromazine, MOF, or HAL. Blood pressure was not changed by either anesthetic nor was it influenced by MEP or OXY. Pulse rate was significantly depressed by the higher doses of OXY following HAL, but was not changed by MEP following either anesthetic.(ABSTRACT TRUNCATED AT 250 WORDS)

Acepromazine↗