PubMed Health⌕ Search

Biomedical subjects

Nagafumi Doi

Publications and source records attributed to Nagafumi Doi.

6 recordsLinked to original sources
PubMed2007

A resistance gene in disguise for schizophrenia?

We examined the hypothesis that -485 T, a novel polymorphism in the promoter region of the neuropeptide Y gene which was shown to be associated with schizophrenia in our previous paper, confers susceptibility to the disease. For a case-control association study, 331 unrelated Japanese schizophrenics (S(1): milder cases in the previous study, n = 212; and S(2): additional severer cases, n = 119) and 199 unrelated normal controls were recruited. Contribution of -485 T to the risk and the severity of the illness was examined by (1) comparing the risk in each genotype in the general population, (2) testing correlations between the gene-dose of -485 T, and the severity of chronic outcome in S(2) assessed with the Positive and Negative Symptom Scale, and (3) comparing the distribution of age at onset in S(1) + S(2) among the three genotypes. -485 T was significantly associated with schizophrenia in S(1) + S(2). Significant negative correlations were observed between the gene-dose and the symptom assessment scores in all items. The homozygote of -485 T showed a second peak frequency in the late-onset group both in males and females, while the homozygote of the alternative allele showed a single peak in the early-onset group. The higher risk of schizophrenia in the heterozygote than in the homozygote of -485 T in the general population did not support the possibility of linkage disequilibrium with a susceptibility gene. -485 T most likely confers resistance but not susceptibility to schizophrenia. An interaction between a nuclear resistance gene and a presumptive pathogenic gene in the mitochondrial DNA was suggested.

Age Distribution↗
PubMed2007

Persistence problem in schizophrenia and mitochondrial DNA.

Schizophrenia, a major psychosis with a strong genetic component, persists over generations despite a clearly reduced reproductive fitness of the patients. This 'persistence' problem has puzzled scientists for long years. A hypothesis of 'balanced polymorphism' proposed by Huxley et al. that the incidence could be sustained by a higher fertility in the siblings of the patients has not been supported by most epidemiological studies. Multiple-genes model, which most geneticists today accept, explains that the loss of susceptibility alleles resulting from the lower fertility of the patients would have a negligible effect on the overall gene pool in the population. We carefully examined the multiple-genes model and proved it cannot account for the persistence problem without unrealistic assumptions and hence the contribution of multiple genes in the nuclear DNA to the heredity of schizophrenia should be considerably limited. We demonstrated a pathogenic gene with a low penetrance, if located in the mitochondrial DNA, could be sustained given a higher fertility of the 'female' siblings and/or a decreased male-female ratio in the offspring of the susceptible females. This hypothesis, coupled with the report which suggests mitochondrial dysfunction in schizophrenia, may encourage a new direction in genetic study of this puzzling disorder.

DNA, Mitochondrial↗
PubMed2006

Resting hypofrontality in schizophrenia: A study using near-infrared time-resolved spectroscopy.

Hypofrontality has been a major finding obtained from functional neuroimaging studies on schizophrenia, although there have also been contradictory results that have questioned the reality of hypofrontality. In our previous study, we confirmed the existence of activation hypofrontality by using a 2-channel continuous-wave-type (CW-type) near-infrared spectroscopy (NIRS) instrument. In this study, we employed a single-channel time-resolved spectroscopy (TRS) instrument, which can quantify hemoglobin (Hb) concentrations based on the photon diffusion theory, to investigate resting hypofrontality. A pair of incident and detecting light guides was placed on either side of the forehead at approximately Fp2-F8 or Fp1-F7 alternately in 14 male schizophrenic patients and 16 age-matched male control subjects to measure Hb concentrations at rest. The patients were also measured with a 2-channel CW-type NIRS instrument during the performance of a random number generation (RNG) task. A reduced total hemoglobin concentration (t-Hb) less than 60 microM (the mean value of the control subjects-1.5 SD) was observed bilaterally in 4 patients and only in the left side in 3 patients. Activation hypofrontality was more manifest in these patients than in the remaining 7 patients despite the same task performance. This decreased t-Hb was related to the duration of illness, and it was not observed in patients whose duration of illness was less than 10 years. These results indicate that resting hypofrontality is a chronically developed feature of schizophrenia. This does not necessarily represent frontal dysfunction, but may reflect anatomical and/or functional changes in frontal microcirculation.

Adult↗
PubMed2006

Electroconvulsive therapy improves severe pain associated with fibromyalgia.

The pathophysiology of fibromyalgia remains unknown. Several reports have recently suggested the novel concept that fibromyalgia is due to the central nervous system becoming hyper-responsive to a peripheral stimulus. The effect of electroconvulsive therapy (ECT) as pain remedication in cases of fibromyalgia without major depressive disorder was studied in a prospective trial lasting three months. All of the patients taking part in the study fulfilled the American College of Rheumatology diagnostic criteria for fibromyalgia. Technetium-99m ethyl cysteinate dimer single photon emission computed tomography was used to assess regional cerebral blood flow (rCBF) before and after a course of ECT. Pain assessment in the patients was undertaken by use of the visual analog scale (VAS) and by evaluation of tender points (TPs). Beck's depression inventory (BDI) was further used to assess depressive mood change in the patients. Our study clearly demonstrated that pain was significantly less severe after ECT, as indicated by the VAS scale for pain and the evaluation of TPs. A further notable observation was that thalamic blood flow was also improved. We conclude that a course of ECT produced notable improvements in both intractable severe pain associated with fibromyalgia and also in terms of thalamic blood flow.

Adult↗
PubMed2006

Electroconvulsive therapy after coil embolization of cerebral aneurysm: a case report and literature review.

We report a case of an uneventful course after electroconvulsive therapy (ECT) of a patient who had undergone coil embolization for an intracranial aneurysm 37 days earlier. There have been no reports until now of ECT after coil embolization. According to histopathologic examinations, it takes approximately 2 weeks after coil embolization for the aneurysm to become fixed. The ECT can be a therapeutic option even in patients with a previous history of coil embolization, as long as it is performed under proper anesthetic management.

Adult↗