Search PubMed⌕ Search

Biomedical subjects

S Kobayashi

Publications and source records attributed to S Kobayashi.

At least 217 records · Page 12Linked to original sources
PubMed2001

Histological study on local invasiveness of clival chordoma. Case report of autopsy.

BACKGROUND: It is well known that clival chordomas invade bony structures; however, their invasiveness of other structures has rarely been reported. We report an autopsy case of clival chordoma in a 61-year-old woman, who underwent surgery 6 times for a period of 8 years, with special reference to its local invasiveness. METHOD AND FINDINGS: The histological studies showed that the tumour grew in the loose connective tissue in multilayers or multilobular fashion, invading the submucous layer in addition to the bone; however, it did not invade other soft tissue, particularly vital neurovascular structures or the dura itself, even in the advanced stage. INTERPRETATION: The dura may serve as a strong barrier against tumour invasion into the intradural space, which emphasises the importance of not injuring the dura, when the tumour is removed extradurally. For radical removal of clival chordoma, it will be necessary to remove the tumour extensively including normal bone and soft tissues surrounding the tumour, especially the mucous membrane, because the normal mucous membrane is surgically difficult to preserve by dissecting it from the invaded submucous layer.

Autopsy↗
PubMed2001

Low anterior interhemispheric approach--a narrow corridor to aneurysms of the anterior communicating artery.

BACKGROUND: Many approaches for clipping anterior communicating artery (ACoA) aneurysms are reported in the literature. We describe here a new approach called "low anterior interhemispheric approach" for clipping of ACoA aneurysms. MATERIALS AND METHODS: A low anterior interhemispheric approach utilizing a unilateral frontal craniotomy flap with minimal unilateral frontal lobe retraction was used in treating four patients harboring an unruptured ACoA aneurysm. The approach axis is directed to the ACoA area itself with minimal exposure to the anterior cerebral vessels. FINDINGS: In all patients, complete neck clipping was possible with minimal brain retraction, without vascular damage and preserved olfaction. INTERPRETATION: This approach is preferred on anatomical grounds for cases of unruptured small and medium sized ACoA aneurysms projecting anteriorly or posteriorly because the anterior communicating artery complex area can be fully visualized with minimal manipulation of the frontal lobes and anterior cerebral arteries.

Adult↗
PubMed2001

Results of direct surgery for aneurysmal subarachnoid haemorrhage: outcome of 2055 patients who underwent direct aneurysm surgery and profile of ruptured intracranial aneurysms.

BACKGROUND AND PURPOSE: The purpose of this study is to evaluate the therapeutic value of our surgical treatment of subarachnoid haemorrhage in a large series with standardized surgical principles. METHODS: Results of 2055 direct operations on ruptured intracranial aneurysms, treated in our institutions, where surgical indications, instruments and techniques were standardized, between 1988 and 1998, were retrospectively evaluated and outcome of the patients was discussed; cases treated by intravascular procedures were excluded. RESULTS: According to the evaluation at discharge, 1083 (52.7%) patients were excellent, 324 (15.8%) good and 223 (10.9%) fair. There were 160 (7.8%) patients of poor outcome and the remaining 265 (12.9%) died. There were no differences in the outcome between pre-operative Hunt & Kosnik grade I and II, Fisher Scale 1 and 2, anterior circulation aneurysms and posterior circulation aneurysms except those at and around the basilar bifurcation, men and women, and those clipped and not clipped. CONCLUSIONS: The factors related to poor outcomes were, age of 60 years or over, pre-operative Hunt & Kosnik grade II or more, Fisher Scale 3 or more, aneurysm size over 15 mm in diameter, and location at and around the basilar artery bifurcation. The results presented in this study show the status of our direct surgical management of subarachnoid haemorrhage in a large series with standardized surgical principles and procedures.

Adolescent↗
PubMed2001

Morphological characteristics of the bony birth canal in patients with developmental dysplasia of the hip (DDH): investigation by three-dimensional CT.

We investigated the three-dimensional morphological characteristics of the pelvis in adult female patients with developmental dysplasia of the hip (DDH), using computerized tomography (CT) images. Forty-two subjects with normal hips and 40 DDH patients were recruited for the study. In the DDH group, the average transverse diameter of the pelvic inlet was significantly less and the average transverse diameter of the pelvic outlet was significantly greater than the measurements in the normal group. Further, the bony birth canal in DDH patients exhibited a higher incidence of anthropoid-type geometry, as defined by a longer sagittal diameter relative to the transverse diameter of the pelvic inlet. These findings indicate a characteristic pelvic geometry and suggest different development of the pelvis in the transverse direction in DDH patients. In addition, the obstetric conjugate length/transverse diameter of the pelvic inlet ratio was correlated to the degree of severity of acetabular dysplasia. This finding suggests that DDH is a manifestation of a developmental characteristic of the pelvis.

Adult↗
PubMed2001

Screening for deletions in interval D16-22 of the Y chromosome in azoospermic and oligozoospermic Japanese men.

The genetic basis of infertility remains unclear in a majority of infertile men. In this study, the Y chromosome long arm involving the DAZ (deleted in azoospermia) gene was screened in order to evaluate the occurrence of microdeletion in Japanese infertile men. One hundred and fifty-seven infertile Japanese men with azoospermia and oligozoospermia were analyzed for microdeletions in interval D16-22 of the Y chromosome, using polymerase chain reaction with sequence-tagged site markers. Sixteen sets of oligonucleotide primers were synthesized for the polymerase chain reaction, and Southern blot analysis was also performed. The men were divided into five categories on the basis of sperm concentration: functional azoospermia (A; n = 24), azoospermia caused by obstruction (AO; n = 20), oligozoospermia I (OI, sperm concentration less than I x 10(5)/ml; n = 33), oligozoospermia II (OII, sperm concentration less than 1 x 10(6)/ml; n = 30), and oligozoospermia III (OIII, sperm concentration less than 1 x 10(7)/ml; n = 50). Thirty fertile men with a sperm concentration of more than 2 x 10(7)/ml were also analyzed as controls. Microdeletions were identified, in 12 (7.6%) of the 157 infertile men, as follows: 1 man in category A, 1 in category AO, 5 in category OI, 4 in category OII, and 1 in category OIII. No deletion was identified in the fertile men. One common region around sY240 was identified in 11 of the infertile men with microdeletions. This locus may contain specific genes for spermatogenesis. The sperm concentration in the ten oligozoospermic men with microdeletions was below 1 x 10(6)/ml. There were no correlations between the severity of spermatogenic defects and the extent of the microdeletions. These results suggested that genes in the interval D16-22 of the Y chromosome might have important roles in spermatogenesis.

Base Sequence↗
PubMed2001

Successful management of breast cancer with liver metastases with medroxyprogesterone acetate treatment.

A 38-year-old woman with cancer in the left breast underwent standard radical mastectomy. The estrogen receptor and progesterone receptor status of the primary tumor was unknown. Ten years after the surgery, a metastatic liver tumor was detected, and chemoendocrine therapy, consisting of cyclophosphamide, epirubicin, 5-fluorouracil (CEF) and medroxyprogesterone acetate (MPA) was initiated. The metastatic liver tumor showed a partial response after 11 cycles of such chemoendocrine therapy. Subsequently, MPA alone was given daily as maintenance therapy, and the disease has remained stable for 6 years. For women with metastatic breast cancer, complete remission is uncommon, and stable disease is a reasonable goal of successful therapy. In this respect, chemoendocrine therapy with CEF and MPA, followed by MPA alone as maintenance therapy, was successful in the patient reported here. Importantly, the patient's quality of life has remained favorable for several years after the partial response was achieved.

Adult↗
PubMed2001

E-cadherin expression associated with differentiation and prognosis in patients with non-small cell lung cancer.

BACKGROUND: E-Cadherin plays a major role in maintaining the intercellular junctions in epithelial tissues. The reduction of E-cadherin expression in cancer cells may be associated with tumor differentiation, metastasis, and a poor prognosis. METHODS: Immunohistochemistry for E-cadherin expression was performed on 109 tumors from patients with non-small cell lung cancer who underwent operations. RESULTS: With respect to membranous immunostaining, 57 carcinomas were E-cadherin-positive, 39 carcinomas E-cadherin-reduced, and 13 carcinomas E-cadherin-negative. The percentage of poorly differentiated tumors in the impaired E-cadherin expression group was significantly higher than that in the E-cadherin-positive group (p = 0.005). Furthermore, the frequency of lymph node metastases in tumors with impaired E-cadherin expression was significantly higher than that in the E-cadherin-positive tumors (p = 0.011). A Cox regression analysis revealed that E-cadherin expression was a significant factor in the prediction of survival for patients with non-small cell lung cancer (p = 0.002). CONCLUSIONS: E-Cadherin expression was associated with tumor differentiation, lymph node metastasis, and prognosis in patients with non-small cell lung cancer.

Cadherins↗
PubMed2001

Pineal apoplexy due to massive hemorrhage associated with cavernous angioma: case report.

BACKGROUND: Pineal apoplexy is a rare apoplectic event in the pineal region with various possible causes. We report a case of massive hemorrhage in the pineal region associated with a cavernous angioma, and discuss the pathogenesis of pineal apoplexy. CASE DESCRIPTION: An 11-year-old girl presented with nausea and vomiting persisting for 1 week. Neuroimaging revealed enlarged ventricles and a 4 cm round mass in the pineal region consistent with hematoma. Two weeks after cerebrospinal fluid drainage, the mass was totally removed via the occipital transtentorial approach. The postoperative course of the patient was uneventful. Magnetic resonance imaging after the operation confirmed two paraventricular lesions with surrounding hemosiderin rings, characteristic of cavernous angioma. Histologic examination showed large hematomas and numerous vascular spaces lined by a single layer of endothelium. The diagnosis was pineal apoplexy associated with cavernous angioma, based on the histologic and radiological findings. CONCLUSIONS: Pineal cavernous angiomas are extremely rare, with only fourteen cases reported previously. We recommend total removal of the causative lesion in cases of pineal apoplexy to prevent repeated bleeding or life-threatening massive hemorrhage.

Brain Neoplasms↗
PubMed2001

Pathologic significance of Staphylococcus saprophyticus in complicated urinary tract infections.

OBJECTIVES: To determine the pathologic significance of Staphylococcus saprophyticus in complicated urinary tract infections. METHODS: We performed a retrospective analysis of specimens demonstrating this organism based on a survey of 9980 urine specimens cultured in our clinic during an 11-year period. Forty-two specimens from 34 patients were positive for S. saprophyticus. RESULTS: S. saprophyticus was isolated in 13 women without underlying urologic disease, and their symptoms were compatible with acute cystitis or acute pyelonephritis. S. saprophyticus was isolated from 7 men and 14 women with underlying urologic disease. In most of these 21 patients, S. saprophyticus was thought not to be a true uropathogen but rather a colonizer, because the isolated organism was usually low in numbers and found with a low degree of pyuria, and the hosts were usually asymptomatic. However, 2 patients demonstrating S. saprophyticus colonization developed sepsis after urologic surgery. CONCLUSIONS: Although this organism is pathogenic in certain circumstances, suggesting the necessity of preoperative antimicrobial elimination, it is usually a colonizer in complicated urinary tract infections.

Adult↗
PubMed2001

Adenocarcinoma of female paraurethral duct showing neuroendocrine differentiation.

Two cases are presented in which a female urethral adenocarcinoma took the form of a diverticular cancer. The pathologic examination of each tumor revealed a columnar/mucinous type of adenocarcinoma with evidence of abundant mucous secretion. Some of the cancer cells were positive on immunohistochemical staining with the conventional neuroendocrine marker chromogranin A, indicating focal neuroendocrine differentiation. The present cases may indicate a possible site of origin for female paraurethral adenocarcinomas.

Adenocarcinoma, Mucinous↗
PubMed2001

Growth hormone, but not luteinizing hormone, acts with luteal peptides on prostaglandin F2alpha and progesterone secretion by bovine corpora lutea in vitro.

Prostaglandin F2alpha (PGF2alpha) is a major physiological luteolysin in the cow. However, injection of PGF2alpha before day 5 (day 0 = estrus) of the estrous cycle dose not induce luteolysis. On the other hand, the early corpus luteum (CL) actively produces PGF2alpha. This indicates that luteal PGF2alpha may play a key role in the refractoriness to PGF2alpha injected during the early luteal phase when angiogenesis is active in the CL. Thus, this study aimed to investigate the possible interaction between pituitary hormones and local factors (luteal peptides) on secretion of PGF2alpha and progesterone (P) by the early bovine CL, and to evaluate the effect of growth hormone (GH) as well as its interactions on production of PGF2alpha in the developing CL. A RT-PCR analysis revealed that mRNA for GH receptor in CL was fully expressed from early in the luteal phase throughout the estrous cycle, while luteinizing hormone (LH) receptor mRNA was expressed less by the early and regressing CL than those at mid or late luteal phases (P < 0.05). For the stimulation test, an in vitro microdialysis system (MDS) was used as a model. Each bovine early CL (days 3-4) was implanted with the MDS, and maintained in an organ culture chamber. The infusion of GH, insulin-like growth factor-I (IGF-I) and oxytocin (OT) increased (P < 0.05) PGF2alpha and P release. In contrast, LH had no effect (P > 0.05) on PGF2alpha secretion and little effect on P release. Unexpectedly, there was no distinct interaction between pituitary hormones and luteal peptides on secretion of PGF2alpha and P. These results indicate that GH is a more powerful stimulator of PGF2alpha and P production in the early bovine CL than LH and suggest that GH and luteal peptides, IGF-1 and OT, contribute to maintenance of elevated PGF2alpha production in the developing bovine CL.

Animals↗
PubMed2001

Detection of YMDD motif mutations in some lamivudine-untreated asymptomatic hepatitis B virus carriers.

BACKGROUND/AIM: It is well documented that long-term lamivudine treatment induces emergence of lamivudine-resistant hepatitis B virus (HBV), namely, YMDD motif mutation in some patients chronically infected with HBV. We previously reported that there were no YMDD mutant viruses in patients with chronic hepatitis B who were not treated with lamivudine. In this series, we examined mutations in the YMDD motif gene in asymptomatic carriers who maintained normal ALT values for 1 year or more. METHODS: Serum samples obtained from 18 patients chronically infected with HBV who consulted our university were used. None of these patients had any experience of using antiviral agents. For detection of mutant viruses, a kit developed in our laboratory was used. RESULTS: Mutations were detected in five of 18 samples: YMDD+YIDD in three samples and YMDD+YVDD+YIDD in two samples. All of these five samples were positive for anit-HBe. In five samples in which mutations were observed, sequencing was carried out following subcloning. CONCLUSION: The present study demonstrates that YMDD mutant viruses are present in lamivudine-untreated asymptomatic hepatitis B virus carriers as well.

Adult↗
PubMed2001

MR imaging of primary leiomyosarcoma of the thyroid gland.

Primary leiomyosarcoma of the thyroid gland is extremely rare and radiological information on this tumor is scant. We presented radiological findings on primary thyroid leiomyosarcoma in a 66-year-old woman in which anaplastic carcinoma was suspected based on clinical and cytological features and discussed the radiological clues to distinguish between the two diseases. Ultrasonography showed an ill-defined hypoechoic mass without halo in the left lobe and the isthmus of the thyroid gland. Computed tomography depicted a low-density mass with calcification and necrosis, which invaded the thyroid cartilage. No lymphadenopathy was seen. The tumor was demonstrated as an isointense mass on T1-weighted MR images and a mass of intermediate signal on T2-weighted images. The tumor showed a fair enhancement on gadolinium-enhanced T1-weighted images. Although the radiological picture was nonspecific, primary thyroid leiomyosarcoma appeared less invasive and far less frequent in developing nodal metastasis than anaplastic carcinoma in light of the literature.

Aged↗
PubMed2001

Mitochondrial small ribosomal RNA is a component of germinal granules in Xenopus embryos.

Mitochondrial large rRNA (mtlrRNA) and small rRNA (mtsrRNA) have been identified as components of germinal granules in Drosophila. We have previously reported that mtlrRNA is present on the germinal granules in Xenopus embryos. Here we report that mtsrRNA is also a common component of the germinal granules. Extra-mitochondrial mtsrRNA is localized on the surface of germinal granules in germ plasm from four-cell to blastula stage, then disappears until the completion of gastrulation. This temporal and spatial distribution pattern is identical to that of mtlrRNA. During the stages when both mitochondrial rRNAs are present around the germinal granules, mitochondrial-type ribosomes, typified by their smaller size, were also present on the surface of the germinal granules.

Animals↗
PubMed2001

Tudor protein is essential for the localization of mitochondrial RNAs in polar granules of Drosophila embryos.

In Drosophila, polar plasm contains polar granules, which deposit the factors required for the formation of pole cells, germ line progenitors. Polar granules are tightly associated with mitochondria in early embryos, suggesting that mitochondria could contribute to pole cell formation. We have previously reported that mitochondrial large and small rRNAs (mtrRNAs) are transported from mitochondria to polar granules prior to pole cell formation and the large rRNA is essential for pole cell formation. Here we show that the localization of mtrRNAs is diminished in embryos laid by tudor mutant females, although the polar granules are maintained. We also found that Tud protein was colocalized with mtrRNAs at the boundaries between mitochondria and polar granules when the transport of mtrRNAs takes place. These observations suggest that Tud mediates the transport of mtrRNAs from mitochondria to polar granules.

Animals↗
PubMed2001

Preparation and properties of thermosensitive hydrogel microcapsules.

Temperature-sensitive hydrophilic gel microcapsules have been newly prepared. That is, poly (L-lysineisopropylamide-terephthalic acid) microcapsules containing water have been obtained by an interfacial polymerization at a water/oil interface between L-lysineisopropylamide and terephthaloyldichloride. The microcapsule changes its size between 33 and 35 degrees C. Under 33 degrees C, the microcapsules are fully spherical and can be redispersed in distilled water, while are aggregated above 35 degrees C. The microcapsules, which are observed to show aggregation above 33 degrees C, can be redispersed by decreasing temperature within a few second. The thermosensitive morphological changes of the microcapsules are thus reversible. Also, it has been shown that the permeability of sodium chloride through the microcapsule membrane changes remarkably between 33 and 35 degrees C, while it is kept almost constant independent of temperature between 25 and 33 degrees C or between 35 and 55 degrees C. The permeability of solutes is higher under 33 degrees C than that above 35 degrees C. Such thermosensitive properties result from the fact that the polymer membrane has isopropylamide groups. That is, L-lysineisopropylamide has a chemical structure similar to N-isopropylacrylamide, the polymer of which, poly (N-isopropylacrylamide), is a thermosensitive hydrogel having its phase transition temperature around 33 degrees C.

Journal Article↗