Measurement of small fibre pain threshold values for the early detection of diabetic polyneuropathy.

AIM: To investigate whether Aδ and C fibre pain threshold values, measured using intra-epidermal electrical stimulation (IES), in people with and without Type 2 diabetes are useful in evaluating diabetic polyneuropathy (DPN) severity. METHODS: Aδ and C fibre pain threshold values were measured in Japanese people with (n = 120) and without (n = 76) Type 2 diabetes by IES. Nerve conduction studies and other tests were performed to evaluate diabetic complications. RESULTS: Aδ and C fibre pain threshold values were high in people with diabetes compared with control subjects (Aδ fibre: 0.050 vs. 0.030 mA, P < 0.01; C fibre: 0.180 vs. 0.070 mA, P < 0.01). Participants with diabetes and neuropathy had significantly higher Aδ and C fibre pain threshold values than participants without neuropathy (Aδ fibres 0.063 vs. 0.039 mA, P < 0.01; C fibres 0.202 vs. 0.098 mA, P < 0.05). C fibre pain threshold values were significantly higher in participants with diabetes and diabetic microvascular complications than in participants without complications. Threshold values increased with complication progression. When DPN was diagnosed according to the Diabetic Neuropathy Study Group in Japan criteria, the cut-off for the C fibre pain threshold values was 0.125 mA (area under the curve 0.758, sensitivity 81.5%, specificity 61.5%). The IES test took less time (P < 0.01) and was less invasive (P < 0.01) than the nerve conduction studies. CONCLUSIONS: Intra-epidermal electrical stimulation is a non-invasive and easy measurement of small fibre pain threshold values. It may be clinically useful for C fibre measurement to diagnose early DPN as defined by the Diabetic Neuropathy Study Group in Japan criteria.

Insulin down-regulates insulin receptor substrate-2 expression through the phosphatidylinositol 3-kinase/Akt pathway.

Insulin receptor substrate (IRS)-1 and IRS-2 are the major substrates that mediate insulin action. Insulin itself regulates the expression of the IRS protein in the liver, but the underlying mechanisms of IRS-1 and IRS-2 regulation are not fully understood. Here we report that insulin suppressed the expression of both IRS-1 and IRS-2 proteins in Fao hepatoma cells. The decrease in IRS-1 protein occurred via proteasomal degradation without any change in IRS-1 mRNA, whereas the insulin-induced suppression of IRS-2 protein was associated with a parallel decrease in IRS-2 mRNA without changing IRS-2 mRNA half-life. The insulin-induced suppression of IRS-2 mRNA and protein was blocked by the phosphatidylinositol (PI) 3-kinase inhibitor, LY294002, but not by the MAP kinase-ERK kinase (MEK) inhibitor, PD098059. Inhibition of Akt by overexpression of dominant-negative Akt also caused complete attenuation of the insulin-induced decrease in IRS-2 protein and partial attenuation of its mRNA down-regulation. Some nuclear proteins bound to the insulin response element (IRE) sequence on the IRS-2 gene in an insulin-dependent manner in vitro, and the binding was also blocked by the PI 3-kinase inhibitor. Reporter gene assay showed that insulin suppressed the activity of both human and rat IRS-2 gene promoters through the IRE in a PI 3-kinase-dependent manner. Our results indicate that insulin regulates IRS-1 and IRS-2 through different mechanisms and that insulin represses IRS-2 gene expression via a PI 3-kinase/Akt pathway.

[The relationship between work factors and psychiatric symptoms--a comparison between anxiety and depression].

The depression scale (Zung Self-rating Depression Scale) and the anxiety scale (State-Trait Anxiety Inventory) have often been used to study the mental health of workers. We carried out a comparative study to determine which these two scales more clearly reflects the work stress. We used two methodologically different materials: a questionnaire survey and mental health consultation records. The questionnaire was sent to 885 male workers in a large industrial company and its related companies, and the consultation cases were 84 male workers coming from the area where the questionnaire survey was conducted. The work problem questionnaire was factored and the four work factors that were obtained were used in the succeeding analyses. The results of the questionnaire survey showed that depression had a higher multiple correlation with the four work factors than did the state anxiety. Similarly, the consultation cases, in which the main symptom was depression, accounted for a little more than 40% of all cases, but the anxiety cases accounted for only 10%-20%. Both studies indicated that depression is a more important manifestation of work stress than anxiety. The questionnaire survey also showed that the "quality-of-work" factor and the "work-quantity/environment" factor had relatively high standardized partial regression coefficients, when depression was predicted by the four work factors. In the case of the consultation cases, more than 50% of the depressive cases were caused by overload. Since the "work-quantity/environment" factor was considered to be closely related to overload, the salient relation between depression and overload agrees with the results of the consultation research.(ABSTRACT TRUNCATED AT 250 WORDS)

Missing peaks in auditory brainstem responses and negative symptoms in schizophrenia.

Auditory brainstem responses (ABRs) were examined in 30 schizophrenic patients and 29 normal subjects. The psychotic symptoms were assessed by the Brief Psychiatric Rating Scale (BPRS) and the Scale for Assessment of Negative Symptoms (SANS) in the patients. At least one of the waves I, II or III was found missing on either side at 80 dBHL (hearing level) in 8 (27%) of the patients but in only one (3%) of the normal subjects. There was a significant association between the missing peaks and the BPRS negative symptom cluster or the total score of the SANS. These results suggest that some schizophrenics, especially those with negative symptoms, have an abnormality of input processing of auditory information in the lower brainstem.

Macropsia, micropsia, and episodic illusions in Japanese adolescents.

The prevalence of episodic macropsia, micropsia, and distortions of time perception was examined by questionnaire in 3,224 high-school students aged 13 to 18 years. About 9% of the students reported having experienced one or more types of episodic illusion within the past 6 months. The prevalence of probable migraine was more than three times higher in students with episodic illusions than in those with no episodic illusions. Experiencing more than one type of illusion was found to be associated with probable migraine. Illusions appeared only during fever or while falling asleep in 25% of a subsample of 1,315 students.