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Biomedical subjects

K Ishizu

Publications and source records attributed to K Ishizu.

At least 37 records · Page 2Linked to original sources
PubMed1999

Nuclear transport of the major capsid protein is essential for adeno-associated virus capsid formation.

Adeno-associated virus capsids are composed of three proteins, VP1, VP2, and VP3. Although VP1 is necessary for viral infection, it is not essential for capsid formation. The other capsid proteins, VP2 and VP3, are sufficient for capsid formation, but the functional roles of each protein are still not well understood. By analyzing a series of deletion mutants of VP2, we identified a region necessary for nuclear transfer of VP2 and found that the efficiency of nuclear localization of the capsid proteins and the efficiency of virus-like particle (VLP) formation correlated well. To confirm the importance of the nuclear localization of the capsid proteins, we fused the nuclear localization signal of simian virus 40 large T antigen to VP3 protein. We show that this fusion protein could form VLP, indicating that the VP2-specific region located on the N-terminal side of the protein is not structurally required. This finding suggests that VP3 has sufficient information for VLP formation and that VP2 is necessary only for nuclear transfer of the capsid proteins.

Amino Acid Sequence↗
PubMed1999

Idiopathic clitoral hypertrophy.

We report a case of clitoral hypertrophy of unknown origin. A 3-year-old girl showed clitoral hypertrophy at birth. Biochemical analysis of peripheral blood and endocrinological examinations were normal. Other virilizing symptoms were not recognized. Clitoroplasty was carried out, and the clitoris has not enlarged 20 months after the operation. Her mother was administered cefotiam and terbutaline (beta-stimulant) during pregnancy because of threatened abortion. No virilizing agents such as progesterone were used during pregnancy.

Abortion, Threatened↗
PubMed1999

[A case of multiloculated retroperitoneal abscess successfully treated by percutaneous drainage with a Malecot catheter].

Percutaneous catheter drainage offers an attractive alternative to open surgical drainage as the first choice in the treatment of retroperitoneal abscess. However, multiloculated abscess is difficult to drain percutaneously. We report a case of multiloculated retroperitoneal abscess successfully treated by percutaneous drainage with a Malecot catheter. A 47-year-old woman complained of fever and left flank pain. The peripheral while blood cell count was 16,800/mm3 and the blood sugar was 369 mg/dl. The computer tomographic (CT) scan showed a large multiloculated mass in the left retroperitoneum. An aspiration needle was inserted into the perinephric mass under ultrasonographic guidance. The definitive diagnosis of abscess was made by aspiration of purulent fluid. A 20 Fr. Malecot catheter was passed over the guide wire under fluoroscopic guidance. Two hundred ml of pus was smoothly aspirated. Streptococcus agalactiae was isolated from the aspirate. Antibiotics and insulin were started. The catheter was retained for 49 days until ultrasonography revealed disappearance of the abscess. One year later, she had no symptoms of recurrence.

Abdominal Abscess↗
PubMed1999

[Two cases of testicular infarction: the usefulness of enhanced MRI for preoperative diagnosis].

The differential diagnosis in acute scrotum, particularly torsion of spermatic cord and epididymitis, is sometimes difficult. An erroneous diagnosis may result in unnecessary and improper treatment. We report two cases of testicular infarction including torsion of spermatic cord, preoperatively diagnosed by enhanced magnetic resonance imaging (MRI). Case 1: A 16-year-old boy presented with a 3-day history of left scrotal swelling and left lower abdominal pain. He had fever and leukocytosis. Antibiotics for 2 days failed to relieve the symptoms. Enhanced MRI showed absence of blood flow in the left testis. Scrotal exploration revealed hemorrhage and necrosis in the left testis. Left orchiectomy and right orchiopexy were performed. Case 2: A 12-year-old boy visited with scrotal swelling and fever 30 hours after an acute onset of left scrotal pain. Enhanced MRI showed absence of blood flow in the left testis. Exploration revealed left necrotic testis with torsion of spermatic cord. Left orchiectomy and right orchiopexy were performed. Our two cases suggested that enhanced MRI, by which the intratesticular blood flow can be evaluated, may be useful for the diagnosis of testicular infarction.

Adolescent↗
PubMed1999

[A case of multiple endocrine neoplasia type 2A (MEN2A) with a mutation in the RET gene].

A 44-year-old woman complained of headache and palpitation. Magnetic resonance imaging showed bilateral adrenal tumors 10 x 9 cm in size on the left side and 8 x 4 cm in size on the right side. CT scan revealed a 0.7 x 0.7 cm mass in the thyroid. Hormonal examinations showed high values of urinary cathecholamines and serum calcitonin. DNA sequence analysis of peripheral white blood cells revealed that codon 634 in exon 11 of the RET gene was mutated from TGC (Cys) to TAC (Tyr). From these findings, a diagnosis was made of MEN2A with bilateral adrenal pheochromocytomas and medullary thyroid carcinoma. Bilateral adrenalectomy and thyroidectomy were performed. The same mutation of the RET gene was detected in all her 3 children, in two of whom, early stage medullary thyroid carcinoma was detected and thyroidectomy was performed. DNA analysis of the RET gene was useful for the diagnosis of carriers of MEN2A and the early detection of medullary thyroid carcinoma.

Adolescent↗
PubMed1999

[Combined treatment with CDDP and radiation effective against neuroendocrine carcinoma of the urinary bladder: a case report].

A case of neuroendocrine carcinoma (small cell carcinoma) of the urinary bladder is presented. A 76-year-old man complaining of dysuria visited our clinic on October 31, 1997. On physical examination, a huge mass was palpable in the lower abdomen. Abdominal and pelvic computed tomographic (CT) scan revealed a huge mass, 6.7 x 6.0 cm in size, with extravesical extension in the anterior wall of the urinary bladder and no metastatic lesions. Percutaneous biopsy of the tumor revealed undifferentiated neuroendocrine carcinoma. The value of serum neuron specific enolase (NSE) was 220 ng/ml (normal range: 0-10 ng/ml). Twenty days after the first CT scan, the tumor had grown to be 12.5 x 11.0 cm in size. He was treated with combination therapy of systemic cisplatin and external pelvic radiation and then achieved complete remission on CT scan and biopsy. The value of serum NSE was normalized. Four months later, abdominal CT scan revealed a huge metastastic lesion in the paraaortic and parahepatic regions, but, no local recurrence in the bladder. The value of serum NSE was 240 ng/ml. He was treated with 4 cycles of systemic combination therapy of cisplatin and etoposide. He achieved partial remission (regression rate: 77%) on CT scan after completion of the first 2 cycles, but the tumor showed rapid re-growth and he died of cancer 1 month later despite another 2 cycles. These combination therapies were effective against neuroendocrine carcinoma of the urinary bladder, although, the duration of the effect was short.

Aged↗
PubMed1998

Quantitative PET analysis of regional cerebral blood flow and glucose and oxygen metabolism in response to fenfluramine in living porcine brain.

The serotonin agonist fenfluramine has been used widely in humans for studying neuronal activation. We carried out the present study in order to determine whether anesthetized pigs could be used for studying effects of fenfluramine on cerebral functions using positron emission tomography (PET). We obtained quantitative measures of regional cerebral blood flow (rCBF) and of glucose and oxygen utilization (rCMRglc and rCMR(O2)) during intravenous administration of fenfluramine, using [15O]water, [18F]FDG and [15O]oxygen, respectively. Fenfluramine (25 mg/h i.v.) caused a significant rise in rCBF and, to a lesser extent, in rCMR2(O2), but it failed to affect rCMRglc. The findings indicate that quantitative estimation of rCBF by repeated injection of [15O]water was more sensitive than either rCMRO2 or rCMRglc for detecting effects of fenfluramine on serotonin neurotransmission in living porcine brain.

Animals↗
PubMed1998

[Urolithiasis associated with Crohn's disease: a case report].

We report a case of urolithiasis caused by surgical treatment for Crohn's disease. A 28-year-old woman was referred to our department for further examination of renal stones from the medical department in September, 1995. She suffered from Crohn's disease and had a history of jejuno-ileal resection because of perforation of the ileum in 1988. Radiographs revealed multiple bilateral renal stones, and the urine oxalate concentration was elevated. She was treated with extracorporeal shock wave lithotripsy and the administration of sodium bicarbonate and citrate, but these treatments did not prevent recurrence and enlargement of stones. Renal function was gradually worsened and we performed transurethral lithotomy and percutaneous nephrolithotripsy. The stones were mainly composed of oxalate calcium monohydrate. A renal biopsy was performed at the operation, showing deposition of crystals in almost all renal tubules. Diet therapy (low oxalate and low fat) and the administration of sodium bicarbonate and citrate were performed strictly and recurrence was not recognized 10 months after complete removal of the stones.

Adult↗
PubMed1997

Superlattice Formation on Star Polymer Solutions

Polyisoprene (PI) stars (arm number f = 4 approximately 237) were prepared by coupling of PI monoanions with tetrachlorosilane or by cross-linking PI anions with divinylbenzene. The structural ordering of such stars was investigated through small-angle X-ray scattering. PI stars (f > ca. 90) formed a body-centered cubic (bcc) structure near the overlap threshold. This structure changed to a mixed lattice of bcc and face-centered cubic structures with increasing polymer concentration.

Journal Article↗
PubMed1997

Cortical processing mechanism for vocalization with auditory verbal feedback.

To investigate the relationship between motor and sensory speech center, cortical activity was examined using PET while normal subjects perceived their own voice which sounded different to the articulated one. The results showed significant activation in the superior temporal gyri with absence of activity in the supplementary motor area (SMA). In a previous study we found significant activation in SMA with no activity in the superior temporal gyrus when normal subjects simply vocalized. Thus, two different cortical pathways for vocalization were delineated: programmed pathway in SMA, and pathway with auditory verbal feedback. The former is thought to be the mature system in the adult, and the latter may be related to speech acquisition.

Adult↗
PubMed1997

The role of the temporal coding system in the auditory cortex on speech recognition.

To elucidate the temporal coding system for speech recognition, we synthesized stimulation sounds which do not contain formant information but do contain temporal information by transforming original sound wave to click sequences. Using this stimulation sound, we performed a recognition test and used PET to examine the cortical activities in normal subjects listening to this sound. The results of the recognition test showed a good perception of the sounds made from sequential speech. The PET study demonstrated significant activation of the superior temporal gyri while listening to the stimulation speech sounds. Our results imply that these stimulation sounds were processed semantically in the auditory cortices. The temporal processing system is thought to make an important contribution to speech recognition.

Adult↗
PubMed1997

Hierarchical Structure of Lattices in Film Formation of Core-Shell Type Polymer Microspheres

By adding polystyrene homopolymer in the solid state, super-lattice structures of poly(4-vinyl pyridine) core-polystyrene shell type polymer microspheres were hierarchically changed from a disordered state to a face-centered cubic via a body-centered cubic. The transition of the lattice structures was investigated from the view point of the excluded volume of the microsphere, which was controlled by a changing of the molecular weights and blend tarios of polystyrene homopolymers.

Journal Article↗
PubMed1997

Presurgical identification of epileptic foci with iodine-123 iomazenil SPET: comparison with brain perfusion SPET and FDG PET.

Iodine-123 iomazenil (IMZ) has excellent characteristics for the quantification of central benzodiazepine receptor (BZR) binding with single-photon emission tomography (SPET). In order to evaluate the clinical value of IMZ SPET for presurgical identification of epileptic foci in patients with medically intractable seizures, we measured the binding potential (BP) of BZR using two IMZ SPET scans and compared the results with brain perfusion SPET and fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET). A total of ten patients with intractable partial epilepsy were examined by electroencephalography, magnetic resonance imaging, FDG PET, brain perfusion SPET and IMZ SPET. After neuroimaging examinations, five patients underwent selective surgery, and all of them have since been free of seizures. Two SPET scans were performed at 15 min (early) and 3 h (late) after intravenous injection of 123I-IMZ (167 MBq). Parametric images of the ligand transport (K1) and binding potential (BP) were calculated by the table look-up method, which is based on a three-compartment two-parameter model, using the standard arterial input function obtained by averaging of six normal volunteers' input functions. BP images delineated the epileptic foci more precisely than either FDG PET or ictal perfusion SPET. FDG PET showed widespread reduction, including the area surrounding the focus, and ictal increase in the cerebral blood flow was seen in possibly activated areas spread from the focus. In four epilepsy cases which originated from the mesial temporal lobe without lateral temporal abnormality, there was no significant decrease in the BP images in the lateral temporal structures, which showed decreased uptake of FDG. It is concluded that parametric images of BP with IMZ are valuable for precise presurgical localization of epileptic foci.

Adult↗
PubMed1997

Cortical activation by monaural speech sound stimulation demonstrated by positron emission tomography.

To investigate how auditory input from each ear contributes to spoken language processing, cortical activation by monaural speech sound stimulation was examined in 12 normal subjects using 15O-labeled water positron emission tomography. Regional cerebral blood flow (rCBF) was measured under four different sound stimulation conditions: (1) silence, (2) white noise, (3) sequential Japanese sentences ("speech"), and (4) Japanese sentences played backward ("reversed speech"), and the results were evaluated by statistical parametric mapping (SPM). Noise induced significant rCBF increase in the contralateral Heschl's gyrus. Speech and reversed speech stimuli caused significant rCBF increase in the contralateral Heschl's gyrus and the bilateral superior temporal gyri, with contralateral activation broader than that in the ipsilateral hemisphere. Monaurally input speech sound signals that reach the contralateral Heschl's gyrus may be processed chiefly and phonologically in the surrounding superior temporal gyrus in the same hemisphere. Comparison of speech activation with reversed speech activation failed to demonstrate a significant difference, which made it difficult to identify the area for lexical and semantic processing.

Acoustic Stimulation↗
PubMed1997

[18F]-fluorodeoxyglucose-positron emission tomography findings in protein infants with severe periventricular leukomalacia and hypsarrhythmia.

UNLABELLED: Two preterm infants with extensive periventricular leukomalacia (PVL) were examined by [18F]-fluorodeoxyglucose-positron emission tomography (FDG-PET) at the corrected ages of 18 and 34 days. They showed similar clinical courses including oculoclonic seizure, hypsarrhythmia and severe mental retardation, in addition, to spastic quadriplegia. FDG-PET study of these two infants with severe PVL disclosed poorly developed metabolic activity in the primary sensorimotor cortex, while the MRI images displayed only periventricular white matter lesions. CONCLUSIONS: Positron emission tomography may disclose cortical involvement in infants with severe periventricular leukomalacia.

Blood Glucose↗
PubMed1997

Sound-induced activation of auditory cortices in cochlear implant users with post- and prelingual deafness demonstrated by positron emission tomography.

Changes of regional cerebral blood flow (rCBF) in the auditory cortices induced by sound stimulation were examined in nine postlingually and five prelingually deaf cochlear implant (CI) users by 15O-labeled water Positron Emission Tomography, and the results were compared with those of eight normal volunteers. Speech stimulation caused significantly greater rCBF increase compared with noise stimulation in the auditory association area in normal and postlingually deaf subjects. In prelingually deaf subjects, however, speech activation of the auditory association area was much less than that found in either of the other two groups. Neuronal networks for speech sound processing in the auditory association area in postlingually deaf individuals are thought be similar to those in normal subjects, while those in prelingually deaf patients who received CI after the speech acquisition period may not develop completely.

Acoustic Stimulation↗
PubMed1997

Quantification of regional cerebral blood flow with continuous infusion of technetium-99m-ethyl cysteinate dimer.

UNLABELLED: We propose a new method to quantify regional cerebral blood flow (rCBF) with continuous infusion of 99mTc-ethyl cysteinate dimer (ECD) and dynamic SPECT. METHODS: Thirteen subjects were studied. Seven subjects had SPECT and PET studies, and the other six subjects were involved in the measurement of blood clearance of 99mTc-ECD. During constant infusion of 99mTc-ECD (740 MBq) over 10 min, dynamic SPECT scans were obtained every 1 min by means of a triple-head rotating SPECT camera. Intermittent arterial blood sampling with octanol extraction was performed every 1 min to estimate the arterial input function. Influx constant (Ku) obtained by Gjedde-Patlak graphical plot method was compared with rCBF measured by PET using 15O CO2 steady state method. In order to simplify the procedure, arterial input function in each subject was estimated by calibration of the arterial blood sampled at the end of the scan to the standard arterial input function estimated from the blood clearance rate in six subjects. RESULTS: Ku was linearly correlated with rCBF (Ku = 0.09 + 0.62 rCBF, r = 0.85, p < 0.05). Ku calculated with the estimated input function (Ku') and rCBF also demonstrated a linear relationship (Ku' = 0.05 + 0.65 rCBF, r = 0.84, p < 0.05). CONCLUSION: The proposed method with one-point arterial sampling is a simple, clinically feasible tool for quantitative measurement of rCBF with 99mTc-ECD.

Adult↗