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Biomedical subjects

H Sumiya

Publications and source records attributed to H Sumiya.

At least 37 records · Page 2Linked to original sources
PubMed1996

Simultaneous observation of regional cerebral blood flow and event-related potential during performance of an auditory task.

Reduced amplitude of the P300 component has been reported consistently in patients with neurological and psychiatric disorders. It is unclear, however, how such patients' cognitive dysfunction is related to their P300 abnormality. Further basic knowledge regarding neural substrates for P300 generation is required for gaining an understanding of the pathological significance of the P300 amplitude reduction. To determine the brain structures involved in P300 generation, we observed the event-related potential and the regional cerebral blood flow (rCBF) in 10 normal subjects performing an oddball discrimination of pure tones. The rCBF value was assessed quantitatively with the aid of single photon emission computed tomography using technetium-99m hexamethylpropylene amine oxime. During the task performance, significant activation was observed in the posterior superior temporal and inferior parietal regions of the right hemisphere. In addition, positive correlation of the task-related increase in rCBF with the simultaneously recorded P300 amplitude was observed in the right but not the left posterior superior temporal region. These findings indicate that activation of the right non-verbal auditory area might modulate P300 generation during pure-tone discrimination.

Acoustic Stimulation↗
PubMed1995

Synthesis of radioiodinated analogs of 2-(4-phenylpiperidino)cyclohexanol (vesamicol) as vesamicol-like agent.

Three iodovesamicol analogs, iodinated at the ortho, meta, and para positions of the 4-phenylpiperidine moiety, were synthesized and labeled with 125I by isotopic exchange reaction. Their potencies as a vesamicol-like drug were evaluated with competitive inhibition studies using (-)[3H]vesamicol. The radiochemical yields were 40-85%, the radiochemical purities exceeded 95% and their specific activities were 370-740 GBq/mmol. The descending order of binding affinity of the tested compounds against the vesamicol receptor was m-iodovesamicol > o-iodovesamicol > p-iodovesamicol. The receptor binding affinity of m-iodovesamicol (IC50 = 133 nM) was comparable with that of vesamicol (IC50 = 109 nM). Therefore, the meta position of the 4-phenylpiperidinyl fragment of vesamicol was the optimum site for iodination, and radioiodinated m-iodovesamicol may serve as a useful radiopharmaceutical for in vitro and in vivo studies of presynaptic cholinergic neurons in rats.

Animals↗
PubMed1993

Noninvasive measurements of regional cerebral blood flow using technetium-99m hexamethylpropylene amine oxime.

The previously reported method for quantitative measurements of whole-brain or hemispheric-brain perfusion using technetium-99m hexamethylpropylene amine oxime (HMPAO) radionuclide angiography is now further developed so that regional cerebral blood flow (rCBF) can be measured. Lassen's correction algorithm is used for the linearization of a curve-linear relationship between the radioactivity in the brain and blood flow as seen with single-photon emission tomography (SPET) images. In this algorithm, the cerebral hemisphere was chosen as the reference region and the correction factor alpha was adapted to rCBF in the reference region. This new method of measuring CBF from SPET has been validated in 33 normal subjects and 22 patients with cerebrovascular disease. Regional CBF values in 20 brain regions of the normal subjects were in good agreement with reported values measured by other methods. Regional CBF in the frontal cortex was greater than that in the temporal, parietal or occipital cortex for the entire age range. This hyperfrontal perfusion tended to be less pronounced with advancing age. Seventeen patients with unilateral brain infarction showed significantly lower rCBF than normal subjects. The infarct core showed a low rCBF value of 11.1 ml/100 g/min on average. An increase in rCBF after acetazolamide administration was observed and measured with this method in five patients with unilateral occlusive vascular pathology. These results suggest that this non-invasive method (without any blood sampling) permits the routine measurement of rCBF from HMPAO SPET tomograms of blood flow.

Acetazolamide↗
PubMed1993

High resolution Tc-99m HMPAO SPECT in a patient with transient global amnesia.

This is a report of a patient who underwent high-resolution brain perfusion SPECT studies during and after an episode of transient global amnesia. During the attack, SPECT imaging showed increased perfusion in the left medial temporal region involving the amygdala and hippocampus. After recovery from amnesia, a follow-up SPECT examination showed slightly decreased perfusion in this region. These findings support the hypothesis that transient global amnesia is associated with transient hyperperfusion in the medial temporal brain structures, and confirm the utility of high-resolution SPECT imaging for the evaluation of the fine details of functional brain anatomy.

Adult↗
PubMed1993

Comparative SPECT study of stroke using Tc-99m ECD, I-123 IMP, and Tc-99m HMPAO.

Brain perfusion SPECT imaging using Tc-99m ethyl cysteinate dimer (ECD) was carried out in 12 patients with chronic cerebrovascular disease. The sensitivity of lesion detection and lesion-to-normal tissue contrast was compared with those of I-123 IMP and Tc-99m HMPAO. Eight patients underwent all three studies and the remaining four patients had Tc-99m ECD and I-123 IMP scans. The sensitivity of lesion detection and lesion contrast was analyzed quantitatively using an asymmetric index determined by the equation: 100 x [right - left[/(right + left). In the cerebral cortex, cerebellum, and white matter, I-123 IMP showed higher lesion sensitivity than Tc-99m ECD and Tc-99m HMPAO. In the striatum and thalamus, Tc-99m ECD and I-123 IMP showed higher lesion sensitivity than Tc-99m HMPAO. I-123 IMP showed the highest lesion contrast in cerebral cortex and cerebellum, whereas Tc-99m ECD showed the highest contrast in thalamus and striatum. In all regions, Tc-99m ECD showed higher lesion contrast than Tc-99m HMPAO. These results suggest regional variation in the sensitivity of lesion detection and lesion contrast of Tc-99m ECD compared to I-123 IMP, and the superiority of Tc-99m ECD to Tc-99m HMPAO.

Adult↗
PubMed1993

[Quantitative analysis of brain perfusion using radionuclide angiography with 99mTc-HMPAO].

A noninvasive simple method for quantitative radionuclide angiography with 99mTc-dl-hexamethyl propylene amine oxime (99mTc-HMPAO). The method of graphical analysis was employed for the evaluation of the unidirectional influx constant (Ku) from the blood to the brain for the tracer. The Ku values were standardized to represent objective and comparable values, brain perfusion indices (BPI), among studied subjects by setting the ratio of ROIbrain size to ROIaorta size to 10. The mean +/- SD of the whole-brain BPI values for the 41 normal controls was 11.15 +/- 2.61, and biphasic reduction with advancing age was observed. The mean of the whole-brain BPI of 7.95 with SD of 2.35 in 103 patients with cerebrovascular disorders was significantly lower than that in normal controls. The right to left ratio of BPI showed wider dynamic range than that of the total counts of SPECT. This technique is quite easy to apply as an adjunct to SPECT and may be helpful in the quantitative evaluation of brain perfusion in routine clinical studies.

Adult↗
PubMed1993

[Testicular function after spermatic cord torsion].

Semen quality and endocrine parameters after spermatic cord torsion were investigated. Of 24 patients evaluated following spermatic cord torsion 12 were treated with bilateral orchiopexy (orchiopexy group), and 12 were treated with ipsilateral orchiectomy and contralateral orchiopexy (orchiectomy group). The average sperm density and the average total sperm count in the orchiectomy group were significantly lower than those in the orchiopexy group (p < 0.05, p < 0.05, respectively). The mean serum follicle stimulating hormone level in the orchiectomy group was significantly higher than that in the orchiopexy group (p < 0.05). These findings suggest a significant decrease in testicular function in the orchiectomy group. All the patients in the orchiopexy group demonstrated a normal semen quality and endocrine parameters during followup. Four of the 8 patients in the orchiectomy group whose duration of followup was more than two years still demonstrated oligozoospermia (< 20 x 10(6)/ml, one of 4 was azoospermia). The average age at operation of these four patients with abnormal semen quality was significantly higher than that of the other 4 patients with normal semen quality (p < 0.05), whereas no significant difference in duration of torsion preceding surgical therapy was observed between these two groups. These findings suggest that subsequent semen quality is likely to remain within normal limits with early surgical treatment by bilateral orchiopexy. Ipsilateral orchiectomy in the younger generation seems to result in less damage of the contralateral testis than in the older generation.

Adolescent↗
PubMed1992

A quantitative approach to technetium-99m hexamethylpropylene amine oxime.

A non-invasive, simple method for the quantitative evaluation of brain perfusion is presented using intravenous radionuclide angiography with technetium-99m hexamethylpropylene amine oxime (99mTc-HM-PAO). Graphical analysis was employed for the evaluation of the unidirectional influx constant (ku) of the tracer from the blood to the brain. The ku values were standardized to provide objective and comparable values, brain perfusion indices (BPI), among studied subjects by setting the ratio of ROIbrain size to ROIaorta size at 10. The whole-brain BPI values for the normal control subjects showed a significant negative correlation with advancing age (r = -0.632, P = 0.0204, n = 13). The mean of the whole-brain BPI of 7.0 (SD = 1.4) in 20 patients with cerebrovascular disorders was significantly lower than that of 10.6 (SD = 1.5) in 13 normal control subjects. The BPI measurements showed only minimal intra- and interobserver variability. Changes of the ratio of ROIaorta size and ROIbrain size did not significantly influence the BPI values. Hemispherical BPI values in 19 subjects (n = 38) showed highly significant correlations with the hemispherical mean cerebral blood flow values obtained from Xenon-133 single photon emission tomography (SPET) (r = 0.926, P = 0.0001 for the early picture method and r = 0.932, P = 0.0001 for the sequential picture method). This technique is easy to apply as an adjunct to SPET and may be helpful in the quantitative evaluation of brain perfusion in routine clinical studies.

Adult↗
PubMed1992

Chromosome abnormalities and rare fragile sites detected in azoospermia patients.

We have examined constitutional chromosome abnormalities and fragile sites in 40 patients with azoospermia. Chromosome abnormalities were found in four cases. Three cases showed a deletion of the long arm of the Y chromosome 46,X,del(Yq) and the other case had a ring of G group chromosome 46,XY,r(G). In a rare fragile sites test, four fragile site carriers were detected and three rare autosomal fragile sites were identified; fra(8)(q24.1), fra(11)(p15.1), and fra(17)(p12). The expression of these fragile sites were induced specifically by AT-specific DNA ligands, such as distamycin A and Hoechst 33258. In addition, one patient was found to be the case of double ascertainment of fragile sites, fra(8)(q24.1) and fra(17)(p12). The overall frequency of distamycin A-inducible fragile sites in azoospermia patients appeared to be higher than those reported for Japanese healthy subjects and cancer patients. However, no significant relation among fragile sites, clinical and histological findings has been detected so far.

Chromosome Aberrations↗
PubMed1992

Xanthofibroma of the adrenal gland.

The authors report on a 43-year-old woman who had undergone unilateral adrenalectomy for a right suprarenal mass. The removed specimen was histopathologically defined as xanthofibroma, a hitherto unpublished adrenal tumour. The connective tissue protein of this rare tumour contained great amounts of collagen, non-collagenous protein and elastin. The significance of such abnormal proliferation of fibrous tissue and the conventional sonographic and CT features of this neoplasm are discussed.

Adrenal Gland Neoplasms↗
PubMed1992

Klinefelter's syndrome with prepenile scrotum.

Two cases of Klinefelter's syndrome with prepenile scrotum were presented. They underwent the operation for prepenile scrotum according to Glenn and Anderson's method. Thereafter urethroplasty was performed in each case. The decrease in response to testosterone in the target organ was noticed in 1 patient, suggesting that some androgen resistance in this case was attributable in part to anomaly of genitalia.

Child, Preschool↗
PubMed1992

Acetazolamide effect on vascular response in areas with diaschisis as measured by Tc-99m HMPAO brain SPECT.

The effects of acetazolamide (Diamox) on vascular response were investigated in areas with intrahemispheric thalamic diaschisis and crossed cerebellar diaschisis using consecutive Tc-99m HMPAO brain SPECT studies before and after Diamox administration. All six patients with thalamic diaschisis and five of eight patients with crossed cerebellar diaschisis at baseline showed significantly augmented perfusion after Diamox administration in the affected thalamus and cerebellum compared with that in the contralateral unaffected areas. These results suggest more dilatation of the arterioles in areas with diaschisis after Diamox administration than in areas without diaschisis. Diamox may produce relative luxury perfusion in areas with diaschisis.

Acetazolamide↗
PubMed1992

[Prognostic factors for progression of superficial bladder cancer].

To clarify prognostic factors for progression of superficial transitional cell carcinoma of the bladder (Ta, T1 and G1, G2), 159 patients, treated by transurethral resection from 1975 to 1988, were analysed concerning clinical findings, laboratory data, endoscopic findings and histopathological findings of the tumor. Histopathological findings included ABH blood group isoantigen (ABH) and Thomsen-Friedenreich antigen (T-ag) as well as other result. Twenty two cases in the series showed progression; 10 with up-grading and up-staging, 12 with either one of them. Advanced age, positive urinary cytology, multiple or broad base tumor, G2 or T1 tumor, negative ABH and abnormal T-ag were closely associated with progression. By multivariate analysis of these factors, ABH, stage of the tumor, T-ag and form were shown to be important prognostic factors in this order. ABH and T-ag were not correlated with other clinicopathological factors in predicting tumor progression. Therefore we concluded that ABH and T-ag were much important for prediction concerning potential for progression of the superficial bladder cancer.

ABO Blood-Group System↗
PubMed1992

[A case of pre-Cushing's syndrome].

A 66-year-old female was admitted to Chiba University Hospital for the evaluation of a left adrenal mass which was incidentally discovered by computerized tomography. The patient had no clinical signs of Cushing's syndrome. Although the plasma ACTH level was suppressed, serum cortisol and urinary 17-OHCS levels were normal. Serum cortisol was not suppressed by dexamethasone and loss of diurnal rhythm of cortisol was observed. Uptake of 131I-aldosterone in the left adrenal gland was noted, but no accumulation was observed in the right one. Left adrenalectomy was performed. The tumor resected was 20 x 22 x 26 mm in size. Pathological diagnosis was adreno-cortical adenoma. Whether slight abnormality of adrenocortical function without clinical symptoms observed in the present case would develop into a clinically typical Cushing's syndrome remains to be solved.

Adenoma↗
PubMed1991

SPECT evaluation of brain perfusion reserve by the acetazolamide test using Tc-99m HMPAO.

This report describes a new approach to the evaluation of brain perfusion reserve using Tc-99m HMPAO SPECT. Consecutive brain Tc-99m HMPAO SPECT studies before and after acetazolamide (Diamox) administration were performed within 30 minutes on 19 patients with significant vascular occlusive lesions. Thirteen patients showed decreased perfusion reserve and four patients maintained perfusion reserve in the affected vascular territories after Diamox administration, providing additional information to baseline Tc-99m HMPAO SPECT in 17 (89%) patients. Although flow augmentation post-Diamox was underestimated, possibly due to the nonproportionality of Tc-99m HMPAO activity to true blood flow, significant changes in the brain perfusion pattern were both visually and quantitatively determined using an image subtraction technique. This consecutive Tc-99m HMPAO SPECT technique seems to be of practical use for the evaluation of brain perfusion reserve and for the improvement of the sensitivity of detecting pathologic areas.

Acetazolamide↗
PubMed1991

Tc-99m HMPAO SPECT analysis of neuroleptic effects on regional brain function.

This report describes a new approach to the evaluation of neuroleptic effects on regional brain function. Using Tc-99m HMPAO SPECT imaging, consecutive brain perfusion studies before and after acute haloperidol administration were performed on three schizophrenic patients and two normal volunteers. The antipsychotic drug ameliorated the hypoactivity in the frontal lobe and suppressed the hyperactivity in the temporo-occipito-parietal lobe selectively in the dominant hemisphere in the schizophrenic patients. It did not exert a significant influence on the brain perfusion pattern in normal volunteers. This nuclear medicine technique seems to be useful for the evaluation of drug effects in psychiatric diseases.

Adult↗
PubMed1991

[Sexual disturbance caused by endocrine dysfunction].

Nineteen cases of sexual disturbance caused by endocrine dysfunction were surveyed for the clinical features. In hypogonadotropic hypogonadism ejaculatory failure was observed in 12 out of 13 cases. On the contrary, 2 of three hypergonadotropic patients preserved their ejaculation. The serum testosterone levels of hypogonadotropic and hypergonadotropic hypogonadism were less than 200 ng/dl. When the testosterone level decreased to less than 100 ng/dl, nine patients out of 13 complained loss of libido and 12 patients complained loss of ejaculation, but six patients preserved erectile function. Hyperprolactinemic patients showed loss of libido in 4, erectile failure in 4 and loss of ejaculation in 2. When good response to hCG test was present or the testicular volume was more than 4 ml, patients with hypogonadotropic hypogonadism showed good response to hCG therapy.

Adult↗