Search PubMed⌕ Search

Biomedical subjects

K Nishihara

Publications and source records attributed to K Nishihara.

At least 91 records · Page 5Linked to original sources
PubMed1994

Decreased cyclosporin A absorption after treatment with GoLytely lavage solution in rats.

Recently we observed a case in which the cyclosporin A absorption decreased after treatment with GoLytely lavage solution in a kidney transplant patient. In this study, we confirmed the decrease of the blood concentration of cyclosporin A after oral administration by GoLytely (Macrogol 3350) based on experiments with rats. The peak blood cyclosporin A concentration, and the area under the blood drug concentration-time curve from 0 to 24 h in the GoLytely-administered group were significantly lower than the control group. In the case of gastrointestinal dysfunction such as diarrhoea, or in treatment with laxatives such as GoLytely lavage solution, whole blood cyclosporin levels must be carefully monitored, and intravenous cyclosporin A may be more suitable for providing adequate immunosuppression.

Analysis of Variance↗
PubMed1994

Relationship between peripheral portal blood flow and liver function in patients with liver cirrhosis. Pulsed Doppler ultrasonographic study.

BACKGROUND: The relationship between portal hemodynamics and liver function in patients with liver cirrhosis remains unclear. METHODS: Using pulsed Doppler ultrasonography, we investigated portal hemodynamics in the trunk and the intrahepatic peripheral vessels and its relation to liver function in cirrhotic patients. RESULTS: The portal blood flow in the right anterior branch (RAB) in cirrhotic patients (n = 40) was significantly lower (p < 0.01) than that in normal subjects (n = 40). In the cirrhotic patients the portal blood flow in the RAB was significantly correlated with the values of serum albumin, total bilirubin, cholesterol, cholinesterase, prothrombin time, and ICG R-15, and that in group C (Child's grading) was significantly decreased (p < 0.01) compared with that in group A. No such difference was found in the main portal vein, the right posterior branch, or the umbilical portion of the left portal vein. CONCLUSIONS: The decrease in blood flow in the RAB is closely related to the impairment of liver function in cirrhotic patients.

Adult↗
PubMed1994

Development of hybrid type artificial bone marrow using sintered hydroxyapatite.

In vivo inducement of hybrid-type artificial bone marrow with hemopoietic inductive microenvironment (HIM) in sintered hydroxyapatite (HA) chamber was carried out. This research is important to disclose the mechanisms of hemopoiesis and is useful for clinical application. In the evolution of vertebrates, cartilage of the inner skeleton changed into bone, having biomechanical properties to form bone marrow cavities. The hemopoietic nests immigrated into the cavities from the spleen. We should be able to induce hemopoietic nests in a hydroxyapatite chamber in place of bone, if we can find optimal structural conditions. Therefore, we tried to artificially induce a hematopoietic field in muscles using sintered porous tubular hydroxyapatite and new type hydroxyapatite plate made by high-pressure gas technique. As a result, not only in the pore sites of tubular hydroxyapatite artificial bone, but at the surface of the new type hydroxyapatite plate implanted in the dorsal muscles, marked differentiation of bone marrow cell clusters of the hematopoietic field could be observed.

Animals↗
PubMed1994

Biomechanical studies on newly tailored artificial dental root.

Artificial roots must carry multiple forces during mastication. Stress distribution around a root depends upon the shape, material, and function of the root. Therefore, for biomechanical studies on artificial roots, triad research on the material, shape, and functional effect upon surrounding tissue is essential. For dental implants, there are two different functional systems against the masticatory force, i.e., gomphosis and ankylosis on osseointegration. Stress analyses of functioning new type (gomphosis) artificial roots were carried out in mandibular and maxilla models to study the triad effect using finite element analysis. The authors have already reported histological and biomechanical studies on the shape and functional effect. To observe the material effect biomechanically, artificial roots made of sintered hydroxyapatite and zirconium oxide were analyzed in the models. Thereafter, animal experiments using dogs were carried out to observe bone formation around artificial roots made of hydroxyapatite and zirconium oxide in the mandible and maxilla. The following results were obtained: The patterns of stress distribution around artificial roots of two different materials were not too different, and were exclusively dependent upon the root shape and structure of the jawbone. Around the artificial roots, bone formation coincided with a moderate stress distributing zone and principal stress trajectories. Through these experiments, the following conclusions were obtained: (a) Osteogenesis around artificial roots coincides with the stress distribution patterns. (b) Stress distribution patterns are dependent very little upon material properties but upon both the artificial root shape and the structure of the jawbone. (c) Optimization of the artificial root shape can be obtained by FEA in the models.

Animals↗
PubMed1994

Biomechanical research on junction system of bone with biomaterials.

Regarding the junction of bioceramics with original bone, which have quite different material constants of Young's modulus and Poisson's ratio from each other, synostosis (ankylosis) cannot be obtained under severe loading conditions. Therefore, it is necessary to introduce a new junction system for the interface between the biomaterial mechanical organ and original bone. The jointing system of dental root to jawbone reflects on the function against mastication. The interface between different mechanical organs with different materials necessitates a specific juncture system under severe loading because of the disparity of material constants. The authors already reported the result of studies on the shape effect of artificial roots in functioning jawbone by means of finite element analysis. Studies on the functional effect of artificial roots in undulated shape were carried out biomechanically by means of finite element analysis using models to investigate an effective juncture system between bone and biomaterials. The results of finite element analysis were compared with the findings obtained from histological specimens. To observe the juncture state of bioceramics with tubular bone cortex, tubular apatite artificial bone was implanted in the femur of a dog. From these studies, the following results and conclusions were obtained: (a) The fibrous juncture system around bioceramics has an important role, after which the principal stress trajectories are converted; and (b) optimal undulated morphology compatible to the artificial bone's juncture system by means of fibrous ligament is essential for remodeling of the bone around the artificial skeletal bone.

Animals↗
PubMed1994

Application of bioactive ceramics for functional surgery in masticatory organs.

Transplanted and replanted autogenous teeth or implanted artificial roots become easily ankylotic. However, if adequate functional loads are applied to them continuously postop with proper fixation, ankylosis can be prevented. The author found this fact through studies on autogenous tooth replantation 20 years ago. Therefore, not only can tooth transplantation, replantation, and artificial root implantation be done successfully with adequate functional loads, but surgical orthodontics as well as plastic operation of jaw deformity can also benefit in the same way. This therapeutic method is called functional surgery. The ankylotic process can be more effectively prevented by applying bioceramic granules. Using these methods, (a) 30 vital teeth in 23 patients were transplanted or replanted. Follow-up duration was 6 to 96 months. (b) Artificial roots made of compact sintered hydroxyapatite (apatite) were implanted under the new concept of functional surgery. In all, 57 artificial roots in 19 patients were implanted and observed for over 5 years. (c) Masticatory skeletal deformities of the viscerocranium were treated with the new concept of functional surgery applying sintered apatite. For this purpose, artificial bone implantation or simple gnathoplasty, tooth transplantation, and artificial root implantation was carried out in 15 patients, after which mastication training was applied with concomitant corrections of function inclination, i.e., oral-perioral habits. In these clinical experiments, excellent favorable results were obtained. The following conclusion was obtained: Introducing the new concept of functional surgery using bioceramics, not only tooth transplantation, as well as artificial root therapeutics, but deformity of the jaw can be steadily treated.

Adult↗
PubMed1994

[Carpal tunnel syndrome: clinical experience of 61 cases].

Carpal tunnel syndrome (CTS) is the most frequent entrapment neuropathy. Appropriate diagnosis and therapy contribute to obtaining good results. We performed carpal tunnel release in 61 patients including 8 cases with chronic renal failure. They included 18 males and 43 females. Age distribution was from 28 to 76 years of age among the males, and from 29 to 82 years of age among the female patients. Bilateral operations were performed in 13 cases (male 5, female 8). Operations were carried out with local anesthesia in all cases except one. The skin incision was about 5 cm on the palmar skin. Hypertrophy of the transverse carpal ligament was found in all cases, with a thickness of 4 mm on the average. Usually, the ligament was as hard as gum in consistency. There were also hypertrophy of the subcutaneous connective tissue and palmar aponeurosis or aberrant muscle in some cases. In CTS following long-term hemodialysis for chronic renal failure, the ligament was very hard and appeared to be partly calcified. All patients improved clinically after the operation. We should understand the characteristic clinical symptoms and signs of CTS. Clinical worsening was prominent at night and/or early in the morning. Definite diagnosis was performed by electrophysiological means. Operative indications are 1) cases whose daily activities are disturbed due to severe symptoms with progressive aggravation, 2) cases with muscle weakness in the distribution of the median nerve, 3) cases with thenar atrophy, 4) cases which, electrophysiologically, are suspected of demyelination of the median nerve. As there were many unpredictable anomalies and variations among the lesions, correct decompression of the median nerve under direct vision is necessary during surgery.

Adult↗
PubMed1994

Small-cell carcinoma combined with adenocarcinoma of the gallbladder. A case report with immunohistochemical and flow cytometric studies.

A small-cell carcinoma combined with adenocarcinoma of the gallbladder was detected in a 71-year-old Japanese woman. A nodular mass measuring 4.0 x 5.0 cm was located in the fundus of the gallbladder, in which a tiny depressed lesion measuring 2 mm in diameter was macroscopically and stereomicroscopically observed. Histologically, the depressed area revealed small-cell carcinoma that consisted of atypical cells with small, round to oval nuclei and scanty cytoplasm and was surrounded by ordinary well-differentiated adenocarcinoma. Immunohistochemically, the tumor cells in an adenocarcinomatous area were diffusely positive for carcinoembryonic antigen and showed an interspersed positivity to serotonin and gastrin, while the tumor cells in the small-cell carcinoma area were negative for both antigens. The nuclear DNA content of the tumor cells of both components was aneuploid; however, the first G0/G1 peak of the small-cell carcinoma was much smaller than that of the adenocarcinoma. These results indicated that the tumor revealed a divergence in functional differentiation, and this feature suggested an initial phase of composite small-cell carcinoma and adenocarcinoma in the gallbladder.

Adenocarcinoma↗
PubMed1993

Intraductal papillary neoplasm of the pancreas.

BACKGROUND: In 1989, Morohoshi et al. reported an intraductal papillary neoplasm of the pancreas (IPNP), which was a morphologically distinct, but rare tumor. METHODS: Two cases with IPNP were analyzed by immunohistochemical and DNA flow cytometric methods. RESULTS: The patients included a 67-year-old man and a 71-year-old woman. Both tumors were characterized by a well-defined papillary growth in the cystically dilated main pancreatic ducts, associated with papillary and nonpapillary hyperplasia. Immunohistochemically, the tumor cells of both cases were positive for the epithelial markers (AE1/AE3 and CAM 5.2), and in one of the two cases, the tumor cells and hyperplastic cells surrounding the tumor conspicuously revealed multiple hormonal markers such as serotonin, somatostatin, glucagon, gastrin, and pancreatic polypeptide. The nuclear DNA content of the tumor cells of the first case, which showed moderate cellular atypia, was considered to be diploid, whereas that of the second case, which revealed severe atypia, was aneuploid. CONCLUSIONS: These results suggested that these tumors arose from multipotential stem cells capable of epithelial and neuroendocrine differentiation, and results of the flow cytometric study was related to the degree of cellular atypia of the tumors.

Adenocarcinoma, Mucinous↗
PubMed1993

Papillary cystic tumors of the pancreas. Assessment of their malignant potential.

BACKGROUND: Although the biologic characteristics of papillary cystic tumors (PCT) generally indicate a good prognosis, a malignant form has been reported. METHODS: Twenty-two examples of PCT were examined to assess their malignant potential by histologic, flow cytometric, and immunohistochemical studies. RESULTS: Three had hepatic, peritoneal, and/or lymph node metastases (metastasizing tumors [MT]); the other 19 PCT had no such metastatic features (nonmetastasizing tumors [NMT]). Venous invasion was detected in all three MT and two NMT. Compared with the 19 NMT, the MT had a higher nuclear grade and more prominent necrobiotic nests characterized by aggregates of cells with pyknotic nuclei and eosinophilic cytoplasm. In the flow cytometric analysis of cellular DNA content, one MT was aneuploid, and eight NMT were diploid. Immunohistochemically, there was no difference between the MT and NMT. CONCLUSIONS: These results support the assumption that venous invasion, nuclear grade, and prominent necrobiotic nests are useful as histologic parameters to detect the malignant potential of PCT.

Adenocarcinoma↗
PubMed1993

Papillary cystic tumours of the pancreas: an analysis by nuclear morphometry.

Papillary cystic tumour (PCT) is a rare, low-grade malignant pancreatic neoplasm, in which the histological criteria for malignancy are still uncertain. We performed a histological examination of 3 metastasizing PCTs, while comparing them with 18 non-metastasizing PCTs, using a computed image analyser. The mean maximum nuclear diameter, the mean standard deviation (SD) of the nuclear diameter, the mean nuclear area and the nuclear-nonnuclear (N/NN) ratio obtained by the image analyser of the metastasizing PCTs (7.23 microns, 2.21 microns, 30.45 microns2, 36.41%) were all significantly larger than those of the non-metastasizing PCT (6.34 microns, 1.59 microns, 23.66 microns2, 23.74%; P < 0.005, P < 0.005, P < 0.005, P < 0.001 respectively). However, there were no statistical differences in either the nuclear ellipsoidity or nuclear regularity. These results suggested that nuclear morphometry might be a useful parameter to define metastatic potential, in addition to histological variables such as venous invasion, nuclear grade and mitotic rate.

Adolescent↗
PubMed1993

Undifferentiated spindle cell carcinoma of the gallbladder: a clinicopathologic, immunohistochemical, and flow cytometric study of 11 cases.

Eleven primary spindle cell carcinomas (SpCCs) of the gallbladder are reported. They occurred in eight women and three men ranging in age from 59 to 80 years (mean age, 66.5 years). Histologically, the tumors showed interlacing bundles of atypical spindle cells with eosinophilic cytoplasm, oval to elongated nuclei, and conspicuous nucleoli. Eight SpCCs contained tiny foci of neoplastic glands similar to those seen in adenocarcinoma, and two of these cases also had small foci of neoplastic squamous epithelium. A gradual transition between the squamous cell carcinoma and the spindle cell component was observed in one tumor. Immunohistochemically, all SpCCs were positive for at least one of the epithelial markers (epithelial membrane antigen, nine cases; AE1/AE3, nine cases; carcinoembryonic antigen, three cases; and EAB 903, one case), and the tumor cells also were immunoreactive to mesenchymal marker (vimentin, eight cases), muscle markers (alpha-smooth muscle actin, one case; desmin, one case), and histiocytic marker (HAM 56, one case). Abnormalities in tumor suppressor gene p53 expression also were found in two of the 11 SpCC cases using monoclonal antibody PAb 1801. In six cases for which data were available flow cytometry revealed aneuploidy in three SpCCs (50%). The survival curve of the SpCC cases (mean survival, 9 months) was less favorable than that of 224 cases of adenocarcinoma of the gallbladder (mean survival, 81 months) (P = .0011). These results indicate that SpCC of the gallbladder is an epithelial tumor with sarcomatoid components and its prognosis is unfavorable.

Adenocarcinoma↗
PubMed1993

Studies on peri-root tissue formation around new type artificial root made of dense hydroxyapatite.

The aim of this study was to examine the wound healing process and tissue development around a new type of artificial root made of dense hydroxyapatite. The newly tailored artificial roots, which have characteristic corrugated configurations with smooth root surfaces, were implanted immediately after extraction of the premolars of adult dogs. After preliminary experiments, the following studies were carried out: for the observation of tissue formation around the artificial root, artificial root with surrounding tissue were extirpated after fixed periods (6-32 weeks) of implantation; to study tissue formation at the artificial root surface, undecalcified specimens with polished surfaces for microanalysis and decalcified specimens for light microscopic observation were prepared after 72 weeks of implantation. The following results were obtained: around the artificial roots in the jawbone, fibrous tissue formation with angled orientation, bone formation resembling alveolar bone proper, and calcified substance formation attaching to the root surface were observed.

Animals↗
PubMed1993

Papillary cystic tumor of the pancreas. Is it a hormone-dependent neoplasm?

In order to attempt to examine the question of whether papillary cystic tumors (PCT) of the pancreas represent a hormone-dependent neoplasm or not, three cases of PCT were biochemically and immunohistochemically investigated. The patients included a 27-year-old man, a 14-year-old girl and a 21-year-old female. Two of the three patients showed measurable biochemical levels of progesterone receptor in the tumors by the dextran-coated charcoal (DCC) method, and an immunohistochemical study revealed that the nuclei of the tumor cells in all the three cases were diffusely positive for progesterone receptor. In the literature, there have been more than 300 female patients of PCT with a significant minority of only twenty male patients, and the mean age of the cases with PCT in men (31.4 years old) is higher than that in women (25.5 years old) (P < 0.05). These results therefore suggest that PCT is a sex hormone-dependent neoplasm.

Adolescent↗
PubMed1993

Carcinoma of the ampulla of Vater.

A consecutive series of 36 Japanese patients with ampullary carcinoma who underwent a pancreatoduodenectomy at the Department of Surgery I, Kyushu University Hospital during the past 20 years were reviewed clinicopathologically to study prognostic factors. A univariate generalized Wilcoxon test showed that preoperative serum carcino-embryonic antigen (CEA) concentration, venous invasion, lymphatic permeation and perineural invasion were significant parameters. A multivariate Cox regression analysis showed that venous invasion was the only significant variable. In a sequential serum CEA follow up of 10 patients, an elevation of serum CEA levels was seen to correspond to the clinical development of a recurrence in six, while a high concentration of serum CEA was not evident despite the clinical manifestation of a recurrence in two, and serum CEA levels remained within the normal limits with no evidence of a recurrence in two others. According to the death certificates of 15 patients, where an exact site of metastasis was available, 11 died from liver metastasis, three from lung metastasis and one from peritoneal dissemination. These findings support the theory that a histologic invasion of the venous space is an independent prognostic factor and close attention should be paid to any signs of haematogenous metastasis, such as to the liver and lung, as well as to a serial serum CEA follow up.

Adenocarcinoma↗
PubMed1993

Composite glandular-endocrine cell carcinoma of the extrahepatic bile duct: immunohistochemical study.

A composite glandular-endocrine cell carcinoma of the extrahepatic bile duct in a 64 yr old Japanese man is reported. A nodular polyp measuring 1.9 x 1.1 cm was located in the confluence of the extrahepatic bile duct. Histologically, the tumor was composed of well differentiated tubular adenocarcinoma and small cell neuroendocrine carcinoma with a transition between the 2 components. The 2 areas of the tumor immunohistochemically revealed a clear-cut difference in functional differentiation. Tumor cells in the glandular component were immunoreactive to both carcinoembryonic antigen (CEA) and CAM 5.2, while those in the small cell area were immunoreactive to neuroendocrine markers such as neuron specific enolase (NSE), chromogranin A and serotonin. These results suggest that the tumor arose from a multipotential stem cell capable of differentiation in 2 directions.

Adenocarcinoma↗