Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dynamic mutations in human genes result from unstable trinucleotide repeats which are expanded within the genome. These expansions of trinucleotide repeats have been shown to be the etiological factors in various neuropsychiatric diseases and other genetic disorders. This hypothesis is supported by various independent studies showing large expansion of trimeric repeats, such as CAG/CTG/CCG/CGG/AAG, in patient DNA samples. These repeats are also identified in other disease loci not clearly related to particular diseases, which indicates that such expansions are one of the general forms of evolution occurring throughout the human genome. The trinucleotide repeat expansions occur during meiosis and are generally irreversible. Accumulation of these repeats over generations eventually ends in a deficiency of replication. There is evidence that certain ethnic groups in the human population have predispositions for expanded repeats related to neuropsychiatric diseases. It is likely that racial/ethnic differences reflect variations, which suggests the possibility of an underlying complex biological process. The present review highlights the importance of repeat expansions in some neuropsychiatric diseases, such as spinal and bulbular atrophy (SBMA), spinocerebellar ataxia (SCA), Huntington's disease (HD), schizophrenia, myotonic dystrophy (DM) and fragile-X syndrome.
Med Sci Monit 2003 Sep
PMID:DNA trinucleotide repeat expansion in neuropsychiatric patients. 1296 Sep 39

The intra- and interindividual variability in apparent steady-state plasma levels of risperidone (RSP) and its metabolite 9-hydroxyrisperidone (9-OHRSP) in schizophrenic patients was investigated. Patients (n = 46, age 26.4 +/- 5.3 years) with diagnosed schizophrenia were treated with a fixed daily oral dose of RSP (1-12 mg/d). The steady-state plasma samples from these patients were collected over a period of 5 years and a total of 549 visits. Plasma concentrations of RSP and 9-OHRSP were determined using a highly sensitive and specific LC-MS-MS method with a detection limit of 0.1 ng/mL. All plasma samples had measurable amounts of 9-OHRSP; however, RSP was nondetectable (<0.1 ng/mL) in 18% of the plasma samples. 9-OHRSP levels were, on average, approximately 22 times higher than those of RSP. The plasma levels of RSP and 9-OHRSP varied widely among patients receiving similar doses of RSP, and the intra- and interindividual variations of RSP and 9-OHRSP plasma levels were found to be large. The data indicated that there was no significant change in the steady-state levels of either RSP or 9-OHRSP during the treatment period. Similarly, the dose-normalized concentration did not vary significantly during the treatment period or with the administered dose. The absence of RSP in many plasma samples (<0.1 ng/mL) and presence of 9-OHRSP at severalfold higher concentrations than RSP indicate that measuring plasma levels of RSP alone may lead to erroneous interpretation in plasma level monitoring studies. The current data support the fact that it is important to measure steady-state levels of total active moiety by analyzing both RSP and 9-OHRSP for plasma drug monitoring.
Ther Drug Monit 2003 Dec
PMID:Intra- and interindividual variations in steady-state plasma concentrations of risperidone and 9-hydroxyrisperidone in schizophrenic patients treated chronically with various doses of risperidone. 1463 51

Olanzapine is an atypical antipsychotic effective in the treatment of schizophrenia. The present study has examined the potential use of target concentration monitoring of olanzapine in plasma as a marker of clinical response and an aid in patient management. Fifty-three patients (mean age 32 years; 40 M, 13 F) with a DSM-IVR diagnosis of schizophrenia completed a 6-week trial of oral olanzapine. Participants received once-daily olanzapine, and their psychotic symptoms were measured with the PANSS (Positive and Negative Symptom Scale) on admission and again after 6 weeks. Responders were classified as having a >/=20% decrease in PANSS scores. Plasma olanzapine was quantified by high-performance liquid chromatography. Receiver operator characteristic (ROC) curve analysis was used to identify a break point in plasma olanzapine that might serve as a surrogate for PANSS classification, and the two methods were compared using the McNemar chi2 test. After 6 weeks the median olanzapine dose was 15 mg/d (range 5-30 mg/d), and the mean plasma olanzapine was 32 micrograms/L at a mean of 13.5 hours after dose. With the PANSS (total), there were 42 responders and 11 nonresponders. ROC curve analysis for total PANSS identified a break point at 23 micrograms/L plasma olanzapine, with the proportions of responders and nonresponders identified by PANSS and the plasma break point being similar. Similar break points were found for the positive, negative, and global PANSS subscores. Nevertheless, these relationships were very modest, and at best the target plasma olanzapine concentration identified only 20% more responders than nonresponders. We suggest that plasma olanzapine monitoring can be used for dose-response optimization, but only to complement the normal clinical evaluation process.
Ther Drug Monit 2003 Dec
PMID:Investigation of target plasma concentration-effect relationships for olanzapine in schizophrenia. 1463 54

Both omega-6 and omega-3 long-chain polyunsaturated fatty acids (LCPUFAs) modulate TH1 and TH2 cell generation, their cytokine production, and cell proliferation and thus may serve as endogenous anti-inflammatory molecules. LCPUFAs suppress the production of tumor necrosis factor-alpha (TNF-alpha) (and so also of OX40, since it belongs to the family of TNFR) and the expression of Bcl-2, suggesting that these fatty acids have the ability to prevent/suppress autoimmune diseases. Human breast milk contains substantial amounts of both omega-3 and omega-6 fatty acids. This indicates that LCPUFAs present in human breast milk suppress the levels of OX40 and decrease the expression of Bcl-xL and Bcl-2 on exposure to self-antigens and thus, protects against the development of autoimmune diseases in later life. In view of this, I propose that supplementation of appropriate amounts of LCPUFAs during perinatal period protects against atopy, asthma, auto-immune diseases, type 1 and type 2 diabetes mellitus, hypertension, coronary heart disease, metabolic syndrome X, lymphomas, leukemias and other cancers, schizophrenia, depression and other adult diseases in which low-grade systemic inflammation plays a significant role. It is also likely that perinatal supplementation of LCPUFAs in adequate amounts modulates the expression of genes concerned with immune response, angiogenesis, central osmo/sodium and glucose sensors etc. This renders various tissues and organs including T cells and macrophages, endothelial cells, hypothalamic neurons, and various cardiovascular tissues to be able to counteract the pathological mechanisms that tend to induce various adult diseases by blunting the inflammatory responses in those who received adequate amounts of LCPUFAs during the perinatal period compared to those who did not.
Med Sci Monit 2004 May
PMID:Perinatal supplementation of long-chain polyunsaturated fatty acids, immune response and adult diseases. 1511 76

The effect of sertraline on the steady-state plasma concentrations of risperidone and its active metabolite 9-hydroxyrisperidone (9-OH-risperidone) was studied in 11 patients with schizophrenia or schizoaffective disorder. To treat concomitant depressive symptoms, additional sertraline, at the dose of 50 mg/d, was administered for 4 weeks to patients stabilized on risperidone (4-6 mg/d). Mean plasma concentrations of risperidone, 9-OH-risperidone, and the active moiety (sum of the concentrations of risperidone and 9-OH-risperidone) did not change significantly during combined treatment with sertraline. At the end of week 4, sertraline dosage was adjusted in some patients on the basis of the individual response and then maintained until the end of week 8. At final evaluation, mean plasma levels of risperidone active moiety were not modified in the 4 patients who were still receiving the initial sertraline dose, but concentrations were slightly but not significantly increased (by a mean 15% over pretreatment) in the subgroup of 5 subjects treated with a final dose of 100 mg/d. In the 2 patients receiving the highest dose of sertraline, 150 mg/d, at week 8 total plasma risperidone concentrations were increased by 36% and 52%, respectively, as compared with baseline values. Sertraline coadministration with risperidone was well tolerated, and no patient developed extrapyramidal symptoms. These findings indicate that sertraline at dosages up to 100 mg/d is not associated with clinically significant changes in plasma risperidone concentrations. However, higher doses of sertraline may elevate plasma risperidone levels, presumably as a result of a dose-dependent inhibitory effect of sertraline on CYP2D6-mediated 9-hydroxylation of risperidone.
Ther Drug Monit 2004 Aug
PMID:Plasma risperidone concentrations during combined treatment with sertraline. 1525 68

It is suggested that perinatal supplementation of long-chain polyunsaturated fatty acids (LCPUFAs) especially; eicosapentaenoic and docosahexaenoic acids prevent schizophrenia in the adult. I propose that schizophrenia could be a low-grade systemic inflammatory disease with its origins in the perinatal period, probably triggered by maternal infection in a genetically susceptible individual that leads to excess production of pro-inflammatory cytokines both in the mother and the fetus. These cytokines, in turn, induce damage to the fetal neurons leading to the adult onset of schizophrenia. I suggest that maternal infection perse interferes with the metabolism of essential fatty acids (EFAs) resulting in deficiency of LCPUFAs that are known to have neuroprotective action. Alternatively, decreased formation of LCPUFAs as a result of decreased activity of D6 and D5 desaturases (due to prematurity) can result in neuronal damage due to the absence/decrease in the neuroprotective LCPUFAs. This is supported by the observation that LCPUFAs suppress the production of pro-inflammatory cytokines, have anti-inflammatory and neuroprotective actions. Furthermore, LCPUFAs are essential for brain growth and development. If this hypothesis is true, it implies that perinatal supplementation of appropriate amounts of LCPUFAs in the right combination is helpful in the prevention of schizophrenia in adult life.
Med Sci Monit 2004 Dec
PMID:Can perinatal supplementation of long-chain polyunsaturated fatty acids prevents schizophrenia in adult life? 1556 90

The effect of lovastatin and thioridazine on the degradation of cocaine in human serum was studied by incubating therapeutic and toxic concentrations of either drug with cocaine in human serum at 37 degrees C. Without these other drugs, cocaine concentrations decreased by an average of 88% in 120 minutes. Lovastatin at all concentrations studied showed a negligible effect on the degradation of cocaine in human serum and did not alter the pseudocholinesterase activity of the serum. In contrast, in the presence of a therapeutic concentration of thioridazine, cocaine concentrations decreased by only 71% during this period of time, and, with a toxic concentration of thioridazine, cocaine concentrations decreased by only 55%. Thioridazine suppressed the pseudocholinesterase activity of human serum by up to 19% during the 120-minute incubation period, and this effect was more pronounced at higher thioridazine concentrations. These findings suggest that thioridazine may prolong the serum half-life of cocaine by inhibiting the pseudocholinesterase-mediated catabolism of cocaine to ecgonine methyl ester. This may be important in cocaine users who are treated with phenothiazines and other structurally similar drugs. They also may be of interest in cocaine-abusing patients who are treated with phenothiazines for schizophrenic disorders.
Ther Drug Monit 2005 Apr
PMID:The effect of lovastatin and thioridazine on the degradation of cocaine in human serum in vitro. 1579 47

Angiotensin-II, a product of angiotensin converting enzyme (ACE) action, regulates vascular tone, stimulates the release of pro-inflammatory cytokines, activates NFkappaB, increases oxidant stress, and suppresses nitric oxide synthesis. Thus, angiotensin-II is pro-inflammatory in nature. Hence, increase in ACE activity and the concentrations of angiotensin-II initiate and perpetuate inflammation. Since ACE is present in many tissues including: the uterus, placenta, vascular tissue, heart, brain, adrenal cortex and kidney, leukocytes, alveolar macrophages, peripheral monocytes, neuronal cells and epididymal cells, this suggests that angiotensin-II may have a role in atherosclerosis, congestive cardiac failure, stroke, bipolar disorder, schizophrenia, dementia, Alzheimer's disease, psoriasis, atopic and non-atopic dermatitis, eczema, several acute and chronic inflammatory diseases, and cancer, conditions in which inflammation is known to play a significant role. This suggests that ACE inhibitors and/or angiotensin-II receptor blockers could be of significant benefit in the management of these conditions. Alternatively, structural analogues of presently available ACE inhibitors and angiotensin-II receptor blockers could be developed such that they are not only useful in the treatment of hypertension and CHF but also possess anti-inflammatory actions.
Med Sci Monit 2005 May
PMID:Is angiotensin-II an endogenous pro-inflammatory molecule? 1587 6

The "glutamate hypothesis" of schizophrenia has emerged from the finding that phencyclidine (PCP) induces psychotic-like behaviors in rodents, possibly by blocking the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor, thereby causing increased glutamate release. N-acetyl aspartylglutamate (NAAG), an endogenous peptide abundant in mammalian nervous systems, is localized in certain brain cells, including cortical and hippocampal pyramidal neurons. NAAG is synthesized from N-acetylaspartate (NAA) and glutamate, and NAA availability may limit the rate of NAAG synthesis. Although NAAG is known to have some neurotransmitter-like functions, NAA does not. NAAG is a highly selective agonist of the type 3 metabotropic glutamate receptor (mGluR3, a presynaptic autoreceptor) and can inhibit glutamate release. In addition, at low levels, NAAG is an NMDA receptor antagonist, and blocking of NMDA receptors may increase glutamate release. Taken together, low central NAAG levels may antagonize the effect of glutamate at NMDA receptors and decrease its agonistic effect on presynaptic mGluR3; both activities could increase glutamate release, similar to the increase demonstrated in the PCP model of schizophrenia. In this report, it is suggested that the central NAAG deficit, possibly through decreased synthesis or increased degradation of NAAG, may play a role in the pathogenesis of schizophrenia. Evidence is presented and discussed from magnetic resonance, postmortem, animal model, schizophrenia treatment, and genetic studies. The central NAAG deficit model of schizophrenia could explain the disease process, from the perspectives of both neurodevelopment and neurodegeneration, and may point to potential treatments for schizophrenia.
Med Sci Monit 2005 Sep
PMID:Central N-acetyl aspartylglutamate deficit: a possible pathogenesis of schizophrenia. 1612 67

The effect of lamotrigine on the steady-state plasma concentrations of the atypical antipsychotics clozapine, olanzapine, and risperidone was investigated in patients with schizophrenia or bipolar disorder stabilized on chronic treatment with clozapine (200-500 mg/day; n = 11), risperidone (3-6 mg/day; n = 10) or olanzapine (10-20 mg/day; n = 14)). Lamotrigine was titrated up to a final dosage of 200 mg/day over 8 weeks, and pharmacokinetic assessments were made at baseline and during treatment weeks 6 and 10, at lamotrigine dosages of 100 and 200 mg/day respectively. The plasma concentrations of clozapine, norclozapine, risperidone, and 9-hydroxy-risperidone did not change significantly during treatment with lamotrigine. The mean plasma concentrations of olanzapine were 31 +/- 7 ng/mL at baseline, 32 +/- 7 ng/mL at week 6, and 36 +/- 9 ng/mL at week 10, the difference between week 10 and baseline being statistically significant (P < 0.05). Adjunctive lamotrigine therapy was well tolerated in all groups. These findings indicate that lamotrigine, at the dosages recommended for use as a mood stabilizer, does not affect the plasma levels of clozapine, risperidone, and their active metabolites. The modest elevation in plasma olanzapine concentration, possibly due to inhibition of UGT1A4-mediated olanzapine glucuronidation, is unlikely to be of clinical significance.
Ther Drug Monit 2006 Oct
PMID:Effect of adjunctive lamotrigine treatment on the plasma concentrations of clozapine, risperidone and olanzapine in patients with schizophrenia or bipolar disorder. 1703 72


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