Search PubMed⌕ Search

Biomedical subjects

Y Kaku

Publications and source records attributed to Y Kaku.

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

Transcollicular approach to intrinsic tectal lesions.

OBJECTIVE: We used a paramedian, infratentorial-supracerebellar, transcollicular approach to resect 11 intrinsic tectal lesions, including 8 tumors and 3 hematomas, in 11 patients. The route of access to the lesions was designed to minimize the anatomic and functional damage to the surrounding structures. METHODS: Access was through one superior colliculus in each of seven patients, through one inferior colliculus in each of two patients, and through the superior and inferior colliculi of one side in each of two patients. RESULTS: Of the eight tumors, three were totally resected, four were nearly totally resected, and one was partially resected. The preoperative ocular symptoms did not change in six of these eight patients and worsened in two, and the neurological deficits, except ocular symptoms, improved in two. All three hematomas were completely removed, along with abnormal blood vessels in the wall of the hematoma cavity; all three of these patients experienced neurological improvement. CONCLUSION: We conclude that the paramedian, infratentorial-supracerebellar, transcollicular approach permits safe removal of intrinsic tectal lesions. Resection of the superior or inferior colliculus or both on one side seems to be neurologically well tolerated.

Adult↗
PubMed1999

Posterior circulation aneurysms. Technical strategies based on angiographic anatomical findings and the results of 60 recent consecutive cases.

Ninety-eight patients with aneurysms of the posterior circulation were admitted to our department from 1993 to 1997. Sixty of them underwent microsurgical treatment, mostly in the acute stage of subarachnoid hemorrhage. Peri- and intraoperative management were carried out according to a structured treatment strategy. Special aspects of surgical technique included extradural selective anterior clinoidectomy for basilar head aneurysms, lateral suboccipital craniotomy and partial condylectomy without laminectomy for aneurysms of the vertebral artery or posterior inferior cerebellar artery, and a trans-Sylvian approach, as used in selective amygdalohippocampectomy, for aneurysms of the posterior cerebral artery. A careful angiographic evaluation of the aneurysms in relation to the neighboring important arteries and bony structures was essential for optimal surgical planning. Forty-nine patients (82%) made a good recovery by 3 months after surgery. The mortality was 7%.

Acute Disease↗
PubMed1998

Renal involvement in Henoch-Schönlein purpura: a multivariate analysis of prognostic factors.

This study is the first report in which the relationship between the progression of renal involvement in Henoch-Schönlein purpura (HSP) and various factors was evaluated using a multivariate analysis. Sixty-five (33.5%) of 194 patients with HSP developed renal involvement from three days to 17 months after the onset of the disease. The plasma coagulation factor XIII (F XIII) activity of 97 patients was examined, and 51 (54.3%) of them showed a decreased activity. A univariate analysis showed that an age at the onset of more than seven years, persistent purpura and a decreased F XIII activity all increased the risk of developing renal involvement. A Cox regression model analysis indicated severe abdominal symptoms, persistent purpura and decreased F XIII activity to be significant risk factors and their hazard ratios were 3.26, 11.53 and 2.27, respectively. Corticosteroid treatment had a hazard ratio of 0.36 and was considered to decrease the risk of developing renal involvement. Based on these findings, patients who have the risk factors for renal involvement should be treated with corticosteroids at the onset of the disease to prevent developing renal involvement.

Adolescent↗
PubMed1998

Intraoperative color-coded duplex sonography for localization of a distal middle cerebral artery aneurysm: technical case report.

OBJECTIVE AND IMPORTANCE: We describe the surgical treatment of a small, distal, middle cerebral artery (MCA) aneurysm, performed using intraoperative color-coded duplex sonography for localization. CLINICAL PRESENTATION: A 55-year-old man presented with a sudden intense headache. Computed tomographic scans revealed a subarachnoid hemorrhage. Angiography demonstrated two MCA aneurysms, one arising from the proximal bifurcation of the right MCA and the other from its distal bifurcation. TECHNIQUE: On Day 1, the proximal MCA aneurysm was clipped via the standard transsylvian approach. The distal MCA aneurysm was identified with the aid of color-coded duplex sonography and was successfully clipped with minimal additional dissection of the sylvian fissure. CONCLUSION: Color-coded duplex sonography provides a two-dimensional image of the brain parenchyma and color-coded flow imaging of cerebral vessels in real time. It may be used for rapid intraoperative localization of small, distally located, cerebral aneurysms.

Cerebral Angiography↗
PubMed1998

Synthesis and antifungal activity of novel thiazole-containing triazole antifungals. II. Optically active ER-30346 and its derivatives.

A series of novel thiazole-containing triazole antifungals was synthesized and evaluated for antifungal activity against a variety of clinically isolated pathogenic fungi in vitro and against systemic candidosis in vivo. These compounds showed potent antifungal activities in vitro and in vivo. In particular, (2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4- difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-butanol (12g; ER-30346) showed potent and well-balanced in vitro activities and potent in vivo efficacy, and had a good safety profile.

Animals↗
PubMed1998

Aneurysm surgery in the acute stage: results of structured treatment.

To evaluate the results of a structured treatment approach to aneurysm surgery in the acute stage, 150 consecutive patients with aneurysmal subarachnoid hemorrhage were studied, including 46 males and 104 females; World Federation of Neurological Surgeons grade I: 21 cases, II: 65, III: 41, IV: 23; day of operation < or = day 3: 103 cases, < or = day 7: 131. Patients underwent angiography on the day of admission or the next followed by surgery. The lamina terminalis and the membrane of Liliequest were routinely opened at surgery. The aneurysm neck was radically clipped after temporary clipping or trapping of the parent arteries. Intraoperative hemodynamic monitoring was used, and the craniotomies were closed without cisternal, epidural, or subgaleal drains. Nimodipine was given perioperatively (48 mg i.v./day for 10 to 14 days). Cases of symptomatic vasospasm were treated with selective intra-arterial administration of papaverine, sometimes combined with angioplasty. Outcome at discharge and 3 months later is good recovery in 61% and 75%, and death in 6% and 7%. The incidence of symptomatic vasospasm was 17%. Devastating vasospasms were observed in 5%. One-third of patients had mean flow velocities exceeding 120 cm/sec determined by transcranial Doppler sonography between days 4 and 14. Communicating hydrocephalus necessitating ventriculoperitoneal shunt occurred in 9%. Our results clearly show a favorable outcome compared with previous reports, especially with respect to the reduced occurrence of fatal vasospasm, hydrocephalus, and technical insufficiency.

Acute Disease↗
PubMed1998

Improvement of cerebral oxygenation patterns and metabolic validation of superselective intraarterial infusion of papaverine for the treatment of cerebral vasospasm.

OBJECT: The purpose of the present study was to assess cerebral oxygenation patterns and brain lactate concentration changes before, during, and after intraarterial infusion of papaverine with or without balloon angioplasty in patients with symptomatic vasospasm. METHODS: A total of 23 vascular territories were successfully treated in 10 patients. In three patients balloon angioplasty was performed before the papaverine infusion. Continuous monitoring of jugular bulb vein oxygen saturation with a fiberoptic catheter and blood sampling allowed the assessment of the cerebral arteriovenous oxygen and lactate differences. A significant and rapid improvement in jugular bulb oxygen saturation was observed in all cases, with critical values reflecting an improvement in cerebral oxygenation after endovascular treatment of vasospasm (p = 0.005). Lactate concentration in the jugular bulb normalized within 4 hours in all patients who had evidence of brain lactic acidosis before superselective intraarterial infusion of papaverine. Recurrence of abnormal metabolic and oxygenation patterns were observed in one case in which an optimal hypertension and hypervolemic therapy could not be achieved after the procedure. CONCLUSIONS: Improvement in cerebral oxygenation as well as prevention of cerebral lactic acidosis can be successfully achieved after intraarterial infusion of papaverine. Normalization of the oxygen supply after endovascular treatment has to be supported by optimal and well-monitored hypertension and hypervolemic hemodilution.

Acidosis, Lactic↗
PubMed1997

Differential induction of constitutive and inducible nitric oxide synthases by distinct inflammatory stimuli in bovine aortic endothelial cells.

Exposure to various combinations of cytokines and lipopolysaccharide (LPS) has been reported to increase NO production in vascular endothelial cells. The molecular entity of the newly expressed nitric oxide synthase (NOS) in endothelial cells, however, has not yet been examined in detail. In this report, we carried out biochemical characterizations and molecular identification of NOS isoform(s) expressed in cytokine/LPS-treated bovine aortic endothelial cells (BAEC). The increased NOS activity in tumor necrosis factor-alpha (TNF-alpha)/LPS-treated BAEC was localized mainly in the cytosolic fraction and Ca2+-independent, whereas that in interferon-alpha,beta(IFN-alpha,beta)/LPS-treated BAEC was preferentially in the membrane fraction and Ca2+-dependent, suggesting that TNF-alpha/LPS increased an inducible NOS (iNOS)-like activity, and IFN-alpha,beta/LPS increased an endothelial constitutive NOS (ecNOS)-like activity. Correspondingly, the different responses to the cytokine/LPS pretreatment were demonstrated in semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) using primers specific for iNOS or ecNOS, that is, TNF-alpha/LPS elicited the expression of iNOS mRNA whereas IFN-alpha,beta/LPS increased that of ecNOS mRNA. A nuclear run-on transcription assay and an inhibition experiment by actinomycin D indicated that the apparent increase of ecNOS in the IFN-alpha,beta/LPS-treated BAEC was at least in part ascribed to the transcriptional activation. The nucleotide sequences of the amplified PCR products in TNF-alpha/LPS- and IFN-alpha,beta/LPS-treated BAEC were 93% and 99% identical to the corresponding regions of human hepatocyte iNOS and bovine ecNOS, respectively. These findings indicated that, in cytokine/LPS-treated BAEC, two NOS isoforms whose molecular natures were closely homologous to the conventional isoforms of iNOS and ecNOS were differently induced in response to distinct inflammatory stimuli.

Amino Acid Sequence↗
PubMed1997

Effectiveness of intra-arterially infused papaverine solutions of various concentrations for the treatment of cerebral vasospasm.

We evaluated the effect of intra-arterially infused papaverine solutions of various concentrations on cerebral vasospasm following subarachnoid haemorrhage. A total of 90 vascular territories in 46 patients with symptomatic cerebral vasospasm after subarachnoid haemorrhage were treated with intra-arterial infusions of papaverine. In all patients, papaverine was infused at the top of the internal carotid artery (ICA). Of the 90 vascular territories, 30 vascular territories in 14 patients were treated with an infusion of 0.1-0.2% (weight/volume) papaverine (Group 1), 30 vascular territories in 16 patients were treated with a 0.4% (w/v) papaverine infusion (Group 2), and 30 vascular territories in 16 patients were treated with an infusion of 0.8-2.0% (w/v) papaverine (Group 3). Among the three groups, we compared the vasodilatory effects of papaverine by assessing the angiographical and clinical improvements following the treatment. When 0.4% (w/v) papaverine was infused, 24 vascular territories (80%) were successfully dilated and 7 patients (44%) showed a marked reversal of neurological deficits due to vasospasm. Therefore, 80 mg/20 ml (0.4% (w/v)) papaverine infused over a 10-minute period proved to be a beneficial concentration. Transient focal neurological deficits due to the infusion of papaverine occurred in 1 Group 1 patient (7%), 1 Group 2 patient (6%), and 7 Group 3 patients (44%). Highly concentrated papaverine had a higher risk of temporary deterioration. In conclusion, the papaverine concentration of 0.4% (w/v) infused at the top of the ICA was a safe and adequate concentration for treating cerebral vasospasm.

Adult↗
PubMed1997

Antigenic and genetic comparisons of Japanese and Australian Simbu serogroup viruses: evidence for the recovery of natural virus reassortants.

The antigenicity and RNA genome structures of five Simbu serogroup bunyaviruses isolated in Japan and Australia were analyzed using monoclonal antibodies (Mabs) raised to Akabane (AKA) virus and oligonucleotide fingerprinting. The virion surface glycoprotein (G1) and the nucleocapsid (N) protein of heterologous viruses showed no reactivity to the Mabs, while the AKA-derived anti-G1 Mab (2F1) reacted with Peaton virus and all three AKA anti-N Mabs reacted with Tinaroo (TIN) virus at almost the same antibody titers as the homologous virus. Oligonucleotide fingerprinting analyses indicated that the three RNA species of all the viruses were unique and distinguishable. However, AKA and TIN viruses exhibited very similar S RNA oligonucleotide fingerprints, while the L and M RNA fingerprints were quite different. The S RNA sequence of TIN virus has been determined and compared with that of AKA and Aino viruses. The results revealed 95.1% S sequence homology between the AKA and TIN viruses. The antigenic and genetic comparisons of AKA and TIN viruses suggest that the two viruses may represent naturally occurring reassortant viruses.

Amino Acid Sequence↗
PubMed1997

Moyamoya disease in Europe, past and present status.

A questionnaire was distributed in early 1996 to 160 leading European neurological, neuro-pediatric and neurosurgical centers to assess the present status of Moyamoya disease in Europe. The response rate was 43%. Information was obtained on a total of 168 patients, of whom 110 had presented before 1992, and 58 from 1993 onward. 82% of the patients were Caucasian. In all other respects, the clinical findings were similar to those observed in Japan. The present study yields an incidence of 0.3 patients per center per year, which is approximately one-tenth of the incidence in Japan. Alongside these results, the history of the recognition and treatment of this disease in Europe is briefly discussed.

Adult↗
PubMed1997

Sequence determination and phylogenetic analysis of the Akabane bunyavirus S RNA genome segment.

The nucleotide sequence of the small (S) RNA segment of Akabane (AKA) bunyavirus was determined. The segment is 858 nucleotides long and contains two overlapping open reading frames (ORFs), which encode the nucleocapsid (N) and nonstructural (NSs) proteins, consistent with other bunyaviruses. Comparisons with the Aino virus S RNA sequence indicated that there is 73.5% identity in nucleotide sequence. However, the sequence identity of the 5' non-coding region of the genomic RNA between these two viruses is only 55%. The N ORFs from 20 Japanese and 2 Australian isolates of AKA virus were sequenced and subjected to phylogenetic analysis. This suggested that AKA virus has evolved in multiple lineages. Twenty-three isolates were grouped into three major clusters, and the cluster which includes recent isolates was subdivided into two branches. Thus, phylogenetic analysis of the AKA virus N protein gene gives a greater insight into bunyavirus evolution.

Genome, Viral↗
PubMed1997

Synthesis and antifungal activity of novel thiazole-containing triazole antifungals.

A new series of thiazole-containing triazole antifungals was synthesized and evaluated for antifungal activity against a variety of clinically isolated pathogenic fungi in vitro and against systemic candidosis in vivo. Among these compounds, (+/-)-1-(2,4-difluorophenyl)-1-[4-(2,4-difluorophenyl) thiazol-2-yl]-2-(1H-1,2,4-triazol-1-yl)ethanol (ER24161) showed the most potent and well-balanced in vitro activities and excellent in vivo efficacy. We also achieved an enantioselective synthesis of the more potent enantiomer of ER-24161.

Animals↗
PubMed1996

Transcapillary ultrafiltration and peritoneal equilibration test in pediatric patients.

The usefulness of the peritoneal equilibration test (PET) in children is unknown. The relationship between transcapillary ultrafiltration and PET was investigated in order to evaluate the usefulness of PET in children. PET was performed on 14 patients undergoing peritoneal dialysis. Their age and bodyweight ranged from 3.8 to 23.6 years and 10.2 to 55.8 kg, respectively. The patients were divided into two groups according to bodyweight; group A patients weighed < or = 40 kg (n = 7) and group B patients weighed > 40 kg (n = 7). There was no significant difference in the mean infusion volume per bodyweight between the two groups, but the mean infusion volume per body surface area was smaller in group A than in group B. Group A showed a more rapid equilibration of dialysate glucose and creatinine than group B. Higher normalized mass transfer area coefficients were evident in group A. In spite of the lower effective glucose gradient in group A, the transcapillary ultrafiltration capacity (TUFC) showed no difference between the two groups. When the slope indices of the regression equations between the two groups were compared, the slopes of the regression in the relationship between TUFC and dialysate (D) ratios D/Do glucose or D/P creatinine in group A were steeper than those in group B. Results of the present study indicate that the larger peritoneal area to infusion volume in patients with smaller body size results in both a rapid equilibration of solutes and sufficient transcapillary ultrafiltration.

Adolescent↗
PubMed1995

Long-term prognosis and prognostic factors of Japanese children with mesangial proliferative glomerulonephritis without IgA deposition.

Mesangial proliferative glomerulonephritis without IgA deposition (non-IgA MesPGN) is commonly detected in biopsy specimens, but the clinicopathological correlation with the long-term prognosis still remains obscure. The aim of our study is to elucidate the long-term prognosis and the clinicopathological prognostic factors in patients with non-IgA MesPGN. We mailed questionnaires to 122 patients with primary glomerulonephritis who were biopsied between 1963 and 1975. Information was obtained from 109 of these 122 patients and 55 were histologically rediagnosed as having non-IgA MesPGN. The histological alterations of glomeruli and tubulointerstitium were classified into five grades. The mean period between the biopsy and the questionnaires was 20.5 years. Six of the 55 patients with non-IgA MesPGN developed end-stage renal failure and histopathological alterations of renal biopsies from these six patients were classified into grade IV or V. The presence of hypertension, heavy proteinuria of over 2+ or renal insufficiency at the biopsy was related to the severe histological changes, a grade of IV or V and to a poor prognosis. The renal survival rate of all the 55 patients was 88.3% at 20 years after the biopsy, while that of the 12 patients with severe histological changes was 48.6%. Although non-IgA MesPGN is considered to be a heterogeneous disease, we cannot ignore the incidence of this disease and thus consider it to be one of the important primary glomerulonephritides that occur in childhood.

Adolescent↗
PubMed1995

Histological analysis of male hybrid sterility induced by the Hst-1 gene in mice.

Hybrid sterility is thought to play an important role in the differentiation and maintenance of respective biological species. In the present study, as a first step to clarify the mechanism of hybrid sterility caused by the Hst-1 gene in mice, the male sterile hybrid between C57BL/6 and M. m. musculus was investigated by histological techniques. Many spermatogonia and primary spermatocytes were observed in the testes of the hybrid sterile mice. Neither secondary spermatocytes nor spermatids were detected throughout the sections. It was noted that some spermatocytes showed degenerations in part of the lumina of the seminiferous tubules. In the chromosomal preparations of primary sterile hybrids, the percentage statistical values for the spermatogonia/leptotene stage were increased and those for the zygotene/pachytene stage were markedly decreased. Neither round nor elongated spermatids were detected throughout the preparations. It was observed that many primary spermatocytes were degenerated. These results suggest that spermatogenesis stops at the leptotene stage and that a small number of cells progress to the next meiosis, but degenerate to die during the pachytene stage.

Animals↗
PubMed1995

[Treatment of facial arteriovenous malformation].

Arteriovenous malformations (AVMs) of the face are notoriously difficult lesions to manage because of the abundant vascular network in this region. We report three cases in which AVMs of the face were treated with endovascular embolization. Two cases with small AVM of the face and auricle were treated with direct puncture of the nidus and embolization with a small amount of n-butyl-cyanoacrylate (NBCA). In the third patient with a large AVM of the cheek, the external carotid artery (ECA) of which had been previously ligated surgically, percutaneous direct puncture of the ECA was performed. Superselective catheterization of each of the feeding arteries and embolization with a small amount of NBCA was then achieved. All cases demonstrated clinical and angiographical improvement. In two cases with a small AVM of the face and auricle, complete obstruction of the nidus was achieved. Direct puncture of the nidus and embolization with a small amount of NBCA was a safe and effective technique for the treatment of facial AVM.

Adult↗