Biomedical subjects

S Maekawa

Publications and source records attributed to S Maekawa.

At least 55 records · Page 3Linked to original sources

PubMed2001

Acute normovolemic hemodilution for radical prostatectomy: can it replace preoperative autologous blood transfusion?

BACKGROUND: Although preoperative autologous blood donation (PAD) is accepted as a standard of care for radical prostatectomy, it is costly, time-consuming and has risks associated with blood storage. Acute normovolemic hemodilution (ANH) is reported to be less expensive and to preserve blood components more effectively than PAD. In the present study, the efficacy and safety of these two autologous blood-collection techniques were compared. METHODS: The study included 16 consecutive patients scheduled for radical prostatectomy. The first eight patients underwent conventional preoperative autologous blood donation of 400 mL 1 week before the operation (PAD group) and the second eight patients underwent acute normovolemic hemodilution followed by immediate operation (ANH group). All blood collected was transfused in the perioperative period. Preoperative and postoperative hematocrit levels in these two groups were compared. RESULTS: There were no differences in preoperative hematocrit, time of operation or operative blood loss between the two groups. In the ANH group, 1080 +/- 160 mL of blood were collected. The postoperative hematocrit level did not differ significantly between the groups. No patient in either group received allogeneic blood transfusion or experienced an adverse event directly related to blood transfusion. CONCLUSION: The two blood-conservation strategies resulted in similar postoperative hematologic outcomes. Given its advantages, which include lower cost, lower risk and higher convenience, ANH is one of the procedures that may replace conventional PAD for use in radical prostatectomy.

Aged↗

PubMed2001

Localization of neuronal growth-associated, microtubule-destabilizing factor SCG10 in brain-derived raft membrane microdomains.

Raft is a mobile membrane subdomain enriched in sphingolipid and cholesterol and also various signaling molecules. Previous observation suggested that brain-derived rafts contain tubulin but that rafts of non-neural origin do not. We hypothesized that SCG10, one of the neuronal growth-associated proteins (nGAPs), might be a neuron-specific molecule that anchors tubulin to neuronal rafts, and we explored biochemically its subcellular localization, interaction with tubulin, and effects on microtubule dynamics. In postnatal rat brain extracts, SCG10 was recovered mostly in membrane-associated fractions, and at least half was included in the raft fraction that was also enriched in GAP-43 and NAP-22. SCG10-enriched brain rafts also contained tubulin, and chemical cross-linking experiments revealed that SCG10 was closely associated with tubulin. In addition, SCG10 was able to inhibit polymerization of tubulin. These results indicate that SCG10 is a component of neuronal rafts as are other nGAPs, and suggest that SCG10 may be involved in signaling events in membranes for cytoskeletal reorganization around neuronal rafts.

Animals↗

PubMed2001

Tubeless cutaneous ureterostomy: the Toyoda method revisited.

PURPOSE: Cutaneous ureterostomy is a less invasive method of urinary diversion and an attractive option especially in patients at high risk. We retrospectively examined the long-term outcome of the method introduced by Toyoda. MATERIALS AND METHODS: Since 1983 the Toyoda cutaneous ureterostomy has been performed in 61 patients (103 renal units) with a minimum of 3 months of followup. The ureteral patency rate was reviewed. RESULTS: Of the 92 renal units (89%) that achieved a tubeless condition 53 (51%) had no hydronephrosis, 23 (22%) had mild to moderate hydronephrosis without the need for treatment, 14 (14%) were not evaluated during followup and 2 (2%) were removed due to subsequent renal pelvic and/or ureteral carcinoma. CONCLUSIONS: A high ureteral patency rate was achieved with the Toyoda cutaneous ureterostomy. This procedure is a reasonable alternative to other forms of urinary diversion.

Adult↗

PubMed2001

Detection of antinuclear antibodies by use of an enzyme immunoassay with nuclear HEp-2 cell extract and recombinant antigens: comparison with immunofluorescence assay in 307 patients.

BACKGROUND: A new enzyme immunoassay (EIA) for automated detection of antinuclear antibodies (ANAs) uses a mixture of HEp-2 cell extracts and multiple recombinant nuclear antigens immobilized on beads. We compared this EIA and an immunofluorescence (IF) assay in a large group of patients and controls. METHODS: We studied 492 healthy individuals and 307 patients with connective tissue diseases (CTDs). Sera were tested by an automated EIA (COBAS Core HEp2 ANA EIA; Roche Diagnostics) and IF. Samples were also tested for eight disease-specific antibodies, including antibodies against U1RNP, Sm, SSA/Ro, SSB/La, Scl-70, Jo-1, dsDNA, and centromere. RESULTS: Areas under ROC curves for the EIA were greater than (P = 0.008-0.012) or numerically identical to areas for the IF method for each of six CTDs studied. ROC areas for EIA were 0.98 (95% confidence interval, 0.95-0.99), 0.99 (0.96-1.00), and 0.99 (0.98-1.00) in systemic lupus erythematosus (n = 111), systemic sclerosis (n = 39), and mixed connective tissue disease (n = 33), respectively. For all 258 CTD patients with conditions other than rheumatoid arthritis (RA), the sensitivity and specificity of the IF method at a cutoff dilution of 1:40 were 92% and 65%, respectively, vs 93% and 79% for the EIA at a cutoff of 0.6. For the IF method at a cutoff dilution of 1:160, sensitivity and specificity were 81% and 87%, respectively, vs 84% and 94%, respectively, for the EIA at a cutoff of 0.9. For 207 sera containing at least one of eight disease-specific ANAs, positivities for the EIA and the IF method were 97.1% and 97.6%, respectively, at cutoffs of 0.6 and 1:40 (P = 0.76). CONCLUSIONS: An EIA that can be performed by a fully automated instrument distinguishes CTDs (except RA) from healthy individuals with both higher sensitivity and specificity than the IF method when the cutoff index was set at 0.9. Moreover, it can be used to exclude the presence of disease-specific ANAs by setting the cutoff index at 0.6 with almost the same efficacy as the IF method.

Adolescent↗

PubMed2001

[Intermittent androgen deprivation treatment of prostate cancer restarted at low level of serum prostate specific antigen: a pilot study].

We report a pilot study on a novel protocol of intermittent androgen deprivation (IAD) treatment of prostate cancer (PC), in which androgen deprivation is restarted when serum prostatic specific antigen (PSA) level reached more than 2 ng/ml and is stopped when PSA level decreased below 0.3 ng/ml. Thirty-two patients (aged 60 to 86 years, median 74 years) with prostate cancer (Stage A in 4 patients, B in 20, C in 1, D in 5, and relapse after radical prostatectomy in 2) were treated with IAD. Median serum PSA prior to the start of endocrine therapy was 15.65 (range 2.67 to 306.3) ng/ml. Eleven patients were treated with lutenizing-hormone-releasing hormone (LHRH) agonist alone and 21 were treated with LHRH agonist plus an antiandrogen. Median duration of first endocrine therapy was 572 (range 100 to 1,543) days. Median serum PSA at the start of first off-phase was 0.038 (range 0.003 to 0.489) ng/ml. After a median of 207 days (range 140 to 843) of follow-up, 19 patients were in the first cycle, 9 in the second cycle, 3 in the third cycle, 1 in the fourth cycle. Two patients developed androgen-independent PC. The median duration of first off-phase of IAD was 287 days. There was a significant inverse relation between the duration of the first on-phase and testosterone level measured 4 months after the cessation of first on-phase therapy (R = -0.518). These results suggest that our protocol provides a reasonable length of off-phase duration and that the long term-androgen deprivation phase might delay the recovery of the testicular endocrine function which should be maintained during the off-phase of IAD.

Aged↗

PubMed2001

[The usefulness of autologous blood transfusion for urologic surgery].

To avoid potential risks associated with homologous blood transfusion including viral infection and graft versus host disease (GVHD), autologous blood donations have been promoted in urologic surgery. We assessed its necessity in the patients undergoing radical retropubic prostatectomy and total cystectomy. A total of 27 patients ranging from 54 to 78 years old donated 400 to 1,200 ml of blood prior to radical prostatectomy (17 patients) and total cystectomy (10 patients). Recombinant erythropoietin was administered in 26 out of 27 patients. The mean hemoglobin concentration was 14.1 g/dl before donation and 12.8 g/dl before operation. The mean volume of surgical blood loss was 1,659 ml ranging from 529 to 2,990 ml in total cystectomy, and 1,438 ml ranging from 553 to 2,841 ml in radical prostatectomy. Overall, 22 out of 27 patients (82%) did not require an additional homologous blood transfusion. In conclusion, autologous blood donation is a safe and useful method to avoid homologous transfusion in radical prostatectomy and total cystectomy. Eight hundred ml of blood donation is suggested to be appropriate prior to these surgeries.

Aged↗

PubMed2001

[Extracorporeal shock wave lithotripsy for upper urinary tract stones using piezoelectric shock wave lithotripsy].

Between August 1999 and July 2000, 123 cases of renal stones and 52 cases of ureteral stones in 116 males and 59 females were treated with the New Piezolith 2500. The average number of sessions required for renal and ureteral stones was 2.50 and 1.48, respectively. At 3 months postoperatively, stone-free rates for renal and ureteral stones were 64.2% and 72.7%, respectively. Assessing residual stones less than 4 mm in diameter as an effective treatment outcome, the efficacy rates for renal and ureteral stones were 94.3% and 86.4%, respectively. Side effects were encountered in 5 cases (2.9%) of high fever and one case (0.57%) of renal subcapsular hematoma. New Piezolith 2500 is effective and safe for the treatment of upper urinary stones.

Adult↗

PubMed2000

Orbital liquid in three-dimensional mott insulator: LaTiO3

We present a theory of spin and orbital states in Mott insulator LaTiO3. The spin-orbital superexchange interaction between d(1)(t(2g)) ions in cubic crystal suffers from a pathological degeneracy of orbital states at the classical level. Quantum effects remove this degeneracy and result in the formation of the coherent ground state, in which the orbital moment of t(2g) level is fully quenched. We find a finite gap for orbital excitations. Such a disordered state of local degrees of freedom on unfrustrated, simple cubic lattice is highly unusual. Orbital liquid state naturally explains observed anomalies of LaTiO3.

Journal Article↗

PubMed2000

Expression of the IgLON cell adhesion molecules Kilon and OBCAM in hypothalamic magnocellular neurons.

The vasopressin (AVP) and oxytocin (OXT) magnocellular neurons in the hypothalamic supraoptic (SON) and paraventricular nuclei (PVN) display reversible structural plasticity of neurons and glial cells under different conditions of neuropeptide secretion. In the present study, we investigated the expression of two immunoglobulin superfamily (IgSF) proteins, Kilon and OBCAM, in the magnocellular neurons by using monoclonal antibodies. Anti-Kilon antibody reacted specifically with the bacterially expressed recombinant Kilon but not with the recombinant OBCAM, and similarly anti-OBCAM antibody specifically recognized the recombinant OBCAM. Western blotting analysis revealed the specific expression of Kilon and OBCAM in the SON homogenates. Although Kilon and OBCAM of the SON homogenates were present as the insoluble form, most Kilon was present in the Triton-insoluble fraction, and OBCAM was localized mainly in the Triton-soluble fraction. Immunocytochemistry revealed Kilon and OBCAM immunoreactivity in the magnocellular neurons of the SON and PVN of the rat hypothalamus compared with outside of the SON and PVN in the hypothalamus. The double-labeling study with confocal microscopy further demonstrated that Kilon immunoreactivity was observed mainly in the dendrites of AVP-secreting neurons and also occasionally OXT-secreting neurons. However, OBCAM immunoreactivity was exclusively seen in the dendrites of AVP-secreting magnocellular neurons. Chronic physiological stimulation by 2% NaCl had no effect on the expression levels of either IgLON protein in the SON. Our study thus demonstrated specific expression of Kilon and OBCAM in the hypothalamic magnocellular neurons, particularly in dendrites, suggesting that they confer on magnocellular neurons the ability to rearrange dendritic connectivity.

Animals↗

PubMed2000

Electronic structure of mott insulators studied by inelastic X-ray scattering

The electronic structure of Mott insulators continues to be a major unsolved problem in physics despite more than 50 years of research. Well-developed momentum-resolved spectroscopies such as photoemission or neutron scattering cannot probe the full Mott gap. High-resolution resonant inelastic x-ray scattering revealed dispersive charge excitations across the Mott gap in a high-critical temperature parent cuprate (Ca(2)CuO(2)Cl(2)), shedding light on the anisotropy of the Mott gap. These charge excitations across the Mott gap can be described within the framework of the Hubbard model.

Journal Article↗

PubMed2000

Absence of TrkB and insulin receptor beta in the Triton insoluble low-density fraction (raft).

Cholesterol- and glycolipid-enriched microdomains within the plasma membrane of animal cells, including neurons, have been purified and used as a low-density membrane domain after extraction with Triton X-100 (raft), or after subcellular fractionation without detergent (LDM). In this study, we compared the protein compositions in the raft and the LDM. Membrane receptors, acylated- and glycosylphosphatidylinositol (GPI)- anchored proteins were enriched in the LDM. Further treatment of the LDM with Triton X-100 excluded the membrane receptors, TrkBs and insulin receptor beta. In the presence of calcium ions, the endogenous tyrosine kinase activities in the LDM and the raft were enhanced, suggesting an important role of calcium ions in the signal transduction via the LDM and the raft.

Acetylation↗

PubMed2000

Conductance quantization and magnetoresistance in magnetic point contacts.

We theoretically study the electron transport through a magnetic point contact (PC) with special attention given to the effect of an atomic scale domain wall (DW). The spin precession of a conduction electron is forbidden in such an atomic scale DW and the sequence of quantized conductances depends on the relative orientation of magnetizations between left and right electrodes. The magnetoresistance is strongly enhanced for the narrow PC and oscillates with the conductance.

Journal Article↗

PubMed2000

Genetic changes in the interferon sensitivity determining region of hepatitis C virus during the natural course of chronic hepatitis C.

Amino acid mutations in the interferon sensitivity determining region (ISDR) are closely associated with the response to interferon in patients with hepatitis C virus genotype 1b (HCV-1b) infection. In this study, 36 patients chronically infected with HCV-1b, with no history of interferon therapy with respect to ISDR changes in HCV were studied. Two serum samples were obtained from each patient, with an average interval of 3.5 years, and predominant nucleotide and amino acid sequences of the ISDR at initial and subsequent time points were compared for each patient. Three of 12 patients with the wild type ISDR (no amino acid mutation in the ISDR compared to the consensus sequence) changed to the intermediate type (1 to 3 mutations) at later time points, whereas the other 9 still had the wild type. Similarly, 2 of 18 patients with the intermediate type changed to the wild type, whereas the other 16 patients continued to have the intermediate type. One of 6 patients with the mutant type (4 or more mutations) changed to the intermediate type, and the other 5 continued to have the mutant type. Although ISDR nucleotide changes/site/year were not significantly different among the 3 groups of patients, percentages of non-synonymous nucleotide changes were greater in the mutant type (63%) than the wild (9%) or the intermediate type (20%) (P < 0.05). These results show that mutations in the ISDR do not occur frequently, suggesting that interferon sensitivity does not change greatly during the natural course of the disease in each patient.

Aged↗

PubMed2000

Flat-elevated and depressed, subtypes of flat early colorectal cancers, should be distinguished by their pathological features.

Flat-type colorectal tumors have are being detected with increasing frequency. It has become clear that these flat lesions contain two subtypes; flat-elevated and depressed lesions. However, their clinicopathological features and roles in colorectal carcinogenesis remain obscure. We classified colorectal adenomas and submucosal invasive cancers into three types: polypoid, flat-elevated, and depressed types. A clinicopathological study of 2505 colorectal tumors (2407 adenomas, 98 submucosal invasive cancers) was then performed. Furthermore, 64 tumors (25 adenomas with high-grade dysplasia, 39 submucosal invasive cancers) from which DNA was extracted were examined for K-ras gene mutation. The percentages of each configuration in the resected materials were 62.0%, 36.4%, and 1.6% of the polypoid, flat-elevated, and depressed types, respectively. The rate of submucosal invasive cancer in the depressed type was always high regardless of size. In the polypoid and flat-elevated types, lesions of larger size showed higher rates of invasion. Analysis of submucosal invasive cancers revealed no adenomatous components in any of the depressed-type lesions; in the polypoid and flat-elevated types the frequencies of cancer with adenomatous components were 83.6% and 77.8%, respectively. The flat-elevated type was more frequently located (77.8%) in the proximal colon than the other types (polypoid type 16.4%, depressed type 25.0%). The incidence of K-ras gene mutation was 47.2%, 18.2%, and 0% in the polypoid, flat-elevated, and depressed types, respectively. These findings suggest that the flat-elevated and depressed types are similar in that they are both morphologically flat and have infrequent incidences of K-ras gene mutation, but these two lesions differ in their pathological features. Especially, depressed type lesions have a tendency to invade the submucosal layer even when they are small. Therefore one should always be aware of this type of lesion during colonoscopic examination.

Adenoma↗

PubMed2000

Adenosquamous carcinoma of the remnant stomach: report of a case.

We report herein the case of a 59-year-old man found to have adenosquamous carcinoma of the remnant stomach which demonstrated rapid progression. The patient was admitted to our hospital to undergo surgery for a papillary tumor of the remnant stomach. Total resection of the remnant stomach with lymph node dissection was performed, and pathological examination confirmed a diagnosis of adenosquamous carcinoma with invasion into the muscularis propria and lymph node metastasis around the perigastric areas. Multiple liver metastases were found 6 months after the operation, for which a right hepatectomy was performed with curative intent; however, he died 2 months later due to lymphangitis carcinomatosa of the lung.

Carcinoma, Adenosquamous↗

PubMed2000

Changes in the localization of NAP-22, a calmodulin binding membrane protein, during the development of neuronal polarity.

NAP-22, a neuronal tissue-enriched acidic membrane protein, is a Ca(2+)-dependent calmodulin binding protein and has similar biochemical characteristics to GAP-43 (neuromodulin). Recent biochemical studies have demonstrated that NAP-22 localizes in the membrane raft domain with a cholesterol-dependent manner. Since the raft domain is assumed to be important to establish and/or to maintain the cell polarity, we have investigated the changes in the localization of NAP-22 during the development of the neuronal polarity in vitro and in vivo, using cultured hippocampal neurons and developing cerebellum neurons, respectively. Cultured hippocampal neurons initially extended several short processes, and at this stage NAP-22 was distributed more or less evenly among them. During the maturation of neuronal cells, NAP-22 was sorted preferentially into the axon. Throughout the developmental stages of hippocampal neurons, the localization change of NAP-22 was quite similar to that of tau, an axonal marker protein, but not to that of microtubule-associated protein-2 (MAP-2), a dendritic marker protein. Further confocal microscopic observation demonstrated the colocalization of NAP-22 and either tau or vesicle-associated protein-2 (VAMP-2). A comparison of the time course of the axonal localization of NAP-22 and GAP-43 showed that NAP-22 localization was much later than that of GAP-43. The correlation between the expression of NAP-22 and synaptogenesis in the cerebellar granular layer, particularly in the synaptic glomeruli, was also investigated. There existed many VAMP-2 positive synapses but no NAP-22 positive ones in 1-week-old cerebellum. On sections of 2-week-old cerebellum, accumulation of NAP-22 to the synaptic glomeruli was clearly observed and this accumulation became clearer during the maturation of the synaptic structure. The present results suggest the possibility that NAP-22 plays an important role in the maturation and/or the maintenance of synapses rather than in the process of the axonal outgrowth, by controlling cholesterol-dependent membrane dynamics.

Animals↗

PubMed2000

Identification of gelsolin as an actin regulatory component in a triton insoluble low density fraction (raft) of newborn bovine brain.

A membrane microdomain enriched in cholesterol and glycosphingolipids, or so called 'raft' region, was found to contain many signal transducing proteins such as GPI-anchored cell adhesion molecules, trimeric G proteins, and protein tyrosine kinases. In previous studies, we showed that the raft region obtained from rat brain contains two cytoskeletal proteins, tubulin and actin, as the major components in addition to these signal transducing proteins. In this study, to know the biochemical mechanisms regulating the cytoskeletal organization in this region, actin regulatory activities in raft were surveyed. We found the presence of a Ca(2+)-dependent actin nucleation promoting activity in raft. The solubilization and column fractionation of this activity combined with western blotting and immunoprecipitation showed that gelsolin is one of the actin regulatory proteins in raft.

Actins↗

PubMed2000

Malignant phyllodes tumor of the prostate.

We report a case of malignant phyllodes tumor of the prostate which is the eleventh reported case in the world. Phyllodes tumor of the prostate is extremely rare and histologically resembles mammary phyllodes tumor. Phyllodes tumor of the prostate is classified into benign, borderline and malignant, but health professionals should carefully follow up the borderline cases in case they take a malignant clinical course. This case was the first to be treated by pre- and postoperative radiation therapy. Although the patient had a slight response to radiation therapy, he eventually developed metastasis. Because malignant phyllodes tumor of the prostate is a very aggressive tumor, people with the condition should undergo systemic chemotherapy as adjuvant therapy.

Adult↗