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Biomedical subjects

S Tanabe

Publications and source records attributed to S Tanabe.

At least 217 records · Page 12Linked to original sources
PubMed1996

[Seizures as a late complication of bromocriptine therapy in patients with prolactin-producing macroadenomas: correlation between lateral extension of the adenoma and seizure onset].

Seizures have been reported as a late complication of medically treated prolactin-producing macroadenomas with lateral extension. Nine prolactin-producing macroadenomas with lateral extension to the cavernous sinus were treated with bromocriptine alone. In all cases, rapid decrease of serum prolactin level was recognized and in eight cases, evidence of tumor shrinkage on CT or MRI was demonstrated. During medical treatment, symptomatic seizures occurred in three cases. MRI showed small residual tumors on the medial surface of the temporal lobe in all these patients. Additionally, a hypointense signal on both T1- and T2-weighted images was recognized around the residual tumor. It was consistent with hemosiderin, a result of intratumoral hemorrhage caused by bromocriptine. On the contrary, the remaining six patients without seizures during treatment did not show abnormal hypointense signals on the medial surface of the temporal lobe. Seizures occur with a high incidence as a late complication of medical treatment of prolactin-producing macroadenomas with intradural supracavernous extension. The patients with seizure show hemosiderin deposit, which may be the trigger of the seizure, within the medial surface of the temporal lobe after bromocriptine therapy.

Adenoma↗
PubMed1996

[Evaluation of carotid artery stenosis with three-dimensional CT angiography and surgical revascularization].

The accuracy of three-dimensional CT angiography (3D-CTA) for delineating atherosclerotic carotid stenosis was examined in comparison with digital subtraction angiography (DSA) in symptomatic patients. In cases undergoing carotid endarterectomy (CEA), the clinical usefulness of 3D-CTA for surgical planning was also evaluated in the light of intraoperative findings. From July 1992 to June 1995, 52 patients suffering from internal carotid ischemia and/or presenting carotid bruit were evaluated to detect carotid bifurcation stenosis by 3D-CTA. Shaded surface reconstruction (SSR) for three-dimensional display and maximum intensity projection (MIP) were employed in multiple projection to evaluate sites of stenosis. DSA was performed in 18 out of 31 patients having atherosclerotic carotid stenosis shown by 3D-CTA. MIP reconstructions accurately delineated sites of stenosis close to DSA and allowed precise depiction of ulcerated plaque and intramural calcification. The percentage of carotid stenosis was determined by comparing the narrowest point to the internal carotid artery (ICA) beyond the bulb on both 3D-CTA and DSA. Assessment of carotid stenosis was highly correlated between 3D-CTA and DSA (r = 0.987, p < 0.0001). In this series, 9 carotid arteries in 8 patients underwent CEA for severe stenosis. 3 patients with ICA occlusion and 1 patient with elongated severe stenosis underwent STA-MCA anastomosis. Using MIP reconstructions and two-dimensional original images it was found that ICA occlusion was apparently distinguished from high grade ICA stenosis. SSR provided valuable informations during CEA for atherosclerotic plaque regarding anatomical relationship with the internal jugular vein and bony structures. This advanced means of 3D-CTA can be adequate as a screening method to detect carotid stenosis in symptomatic patients and useful for surgical planning of CEA and post-operative follow-up examination.

Angiography, Digital Subtraction↗
PubMed1996

[Prognosis after total removal of craniopharyngiomas via the frontobasal interhemispheric approach].

Prognosis after total removal of craniopharyngiomas via the frontobasal interhemispheric approach is reviewed. Seventeen patients with craniopharyngiomas were operated on in Sapporo Medical University Hospital between January, 1985 and December, 1993. In eleven patients, lamina terminalis was incised and in the last six patients, it was left intact. Tumors were completely resected in all patients. After removal of the tumor, hypothalmic--pituitary functions, visual functions and psychometric functions were examined. Two of the 17 cases showed hypernaturemia and fourteen (82%) had permanent DI. Fourteen patients are receiving DDAVP and all are receiving endocrine replacement. Of fourteen patients who had disturbance of their visual acuity, nine (64%) improved. Five of six patients (83%) who presented visual field defect showed improvement in their deficits. Thirteen patients had a psychometric assessment at the time of follow-up examination. Full-scale intelligence quotient scores were distributed as follows: three above 120, five between 90 and 109, three between 70 and 79 and two below 69. Four (32%) had some impairment of memory. Concerning the QOL after total removal of craniopharyngiomas via the frontobasal interhemispheric approach, thirteen patients (76%) are leading normal lives, and three (18%) are leading nearly normal lives but require some help to overcome mild deficits. One (6%) has suffered a significant handicap.

Adolescent↗
PubMed1996

[Hearing preservation and tinnitus following removal of acoustic neurinomas].

Thirty-five cases of unilateral acoustic neurinomas were analyzed with special reference to the postoperative eighth cranial nerve function. An additional three cases of bilateral acoustic neurinomas associated with neurofibromatosis were also analyzed. Out of a total of 40 neurinomas in all, 38 cases were retrospectively reviewed. The thirty-five cases of unilateral acoustic neurinomas were summarized as follows. The patients' age ranged from 23 to 69 years old. The tumor size varied as follows; 7 cases were confined to the internal acoustic meatus, 4 cases were 20 mm or less in their maximum diameter, 13 cases were 30 mm or less, and 11 cases were more than 30 mm. The consistency of the tumor was classified as being solid in 27 cases, and being cystic in 8 cases. Hearing had been maintained in 27 cases on admission, serviceable in 17 cases, unserviceable in 10 cases and deaf in 8 cases. Operations were performed via the retromastoid suboccipital approach in all cases. The facial nerve was anatomically preserved in all cases. On the other hand, the cochlear nerve was anatomically preserved in 14 out of 35 cases (40%). The preservation ratio of the cochlear nerve showed a negative correlation to the tumor size. In 17 cases with preoperative serviceable hearing, preservation of the cochlear nerve was attempted, which resulted in a 65% anatomical preservation. However, hearing was preserved in 4 cases (36%). Serviceable hearing was preserved in only 2 cases. Tinnitus developed in 20 cases preoperatively, and then occurred postoperatively in 11 cases. Tinnitus was prominently aggravated in 2 cases in which the cochlear nerves were preserved, which resulted in unserviceable hearing. There was a statistically significant correlation between cochlear nerve preservation and the postoperative presence of tinnitus (Fisher's exact probability test: P = 0.0106 < 0.05). Tinnitus was aggravated just after the operation. However, it gradually improved and vanished as the hearing showed a recovery to a slight degree in one case. Three cases of bilateral acoustic neurinomas in neurofibromatosis were also summarized. One case received the operation only on the unilateral side. The remaining two cases were operated bilaterally. To preserve serviceable hearing on at least one side, partial removal of the tumor was performed under the monitoring of auditory brain stem response and/or cochlear microphonic potential. Serviceable hearing on at least one side was maintained in all three cases. In conclusion, hearing preservation can be expected after removal of the acoustic neurinomas under the following situations; hearing acuity of less than 50-60dB in preoperative pure tone audiogram, tumor size of less than 20 mm in maximum diameter, cases with preservation of cochlear nerve and of the internal auditory artery during the operation, and no injury to the labyrinth during the operation. In some cases, tinnitus becomes aggravated in the case with cochlear nerve preservation associated with unserviceable hearing. Furthermore, the degree of tinnitus shows a decrease as postoperative hearing improves in some cases.

Adult↗
PubMed1996

[Characteristics of visual impairment complicated with planum sphenoidale and tuberculum sellae meningiomas and their surgical results].

It is well known that it is difficult to remove the planum sphenoidale and tuberculum sellae meningioma without damaging the optic nerves. The visual outcome after this operation has been unacceptable in such tumors, especially in large ones. This review propounds a strategy to secure visual acuity through operation. A total of eight cases are summarized. In five midline symmetrical meningiomas, the tumors compressed the nerves at the portion of the optic chiasma, causing a typical bitemporal hemianopsia. Four large tumors were resected by the frontobasal interhemispheric approach to minimize the intraoperative damage to the optic chiasma, and a small one was removed by the pterional approach. Visual deficits were recovered immediately after the operation in all cases without any surgical complications. Three meningiomas were attached to the lateral part of the planum sphenoidale or tuberculum sella. Although the sizes were relatively small in all cases, they caused ipsilateral severe visual loss by direct compression to optic nerves. MRI and three-dimensional CT angiography showed the tumor extension into the optic canal. The ipsilateral pterional approach was selected in these cases. To avoid additional nerve damage, we tried to reduce the tension of nerves which were compressed by the tumors. We removed the anterior clinoid process and opened the optic canal before surgical manipulation of the tumor. In two cases, tumors severely compressed the optic nerves from the medial side, and nerves were stretched laterally. Great care was required to separate the optic nerves from tumors in those two cases. In contrast, the resection seemed to be very easy in one of the cases where the optic nerve was displaced infero-medially. Visual symptoms were improved in all cases, although one case became worse temporarily. Although planum sphenoidale and tuberculum sellae meningiomas are still troublesome, appropriate preoperative management would allow us to expect an excellent visual outcome. Especially, selection of the surgical approach should be based on the anatomical analysis of the nerve displacement.

Adult↗
PubMed1996

[A case of primary anterior mediastinal liposarcoma with a heterotopic mass in the pericardium of the same histology].

We experienced a case of primary anterior mediastinal liposarcoma with a heterotopic mass in the pericardium of same histology. Twenty reported cases in Japan were also studied. The patient was a 50-year-old male who visited the hospital because of an abnormal shadow on a chest X-ray. The diagnosis of anterior mediastinal tumor was confirmed by a chest CT. The patient underwent a complete resection of the mediastinal and intrapericardial masses. The histologic diagnosis was a well differentiated liposarcoma of Enzinger's classification. No evidence of recurrence or metastasis was detected in the third postoperative year. Liposarcoma is rarely seen in the mediastinum. Since radiotherapy and chemotherapy are ineffective therapeutic modalities, surgery would be the treatment of choice and complete surgical resection is mandatory.

Heart Neoplasms↗
PubMed1995

Isomer-specific analysis of polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) in red fox and human adipose tissue from central Italy.

The general exposure of humans and foxes to polychlorinated biphenyls (PCBs) and DDT in Italy was determined by analysis of adipose tissue samples collected from 1991-1992. sigma PCB concentrations varied between 1.0 and 2.6 micrograms/g (wet wt.). sigma DDT concentrations ranged from 1.6 to 5.0 micrograms/g (wet wt.). About thirty-five PCB congeners were identified in most samples. PCB congeners of IUPAC Nos. 138, 153, and 180 were the most abundant compounds, accounting for an average of 50% of the sigma PCBs in humans and 64% in foxes. Generally, higher chlorinated biphenyls and those with a 2,4,5-chlorine substitution in one ring and at least one substitution in the 4-position of the other ring were preferentially accumulated. Coplanar PCB congeners were detected at considerable concentrations and there is no sign of decline in their concentrations with respect to previously reported data. IUPAC Nos. 118, 156 and 126 were the main contributors to toxicity in humans and foxes. The significant contribution of mono-ortho congeners in humans and non-ortho congeners in foxes suggests that differences in metabolic potential may affect the PCB toxicity pattern.

Adipose Tissue↗
PubMed1995

Blood flow velocity in the common carotid artery in humans during graded exercise on a treadmill.

Cerebral blood volume flow and flow velocity have been reported to increase during dynamic exercise, but whether the two increase in parallel and whether both increases occur as functions of exercise intensity remain unsettled. In this study, blood flow velocity in the common carotid artery was measured using the Doppler ultrasound method in eight healthy male students during graded treadmill exercise. The exercise consisted of stepwise progressive increases and decreases in exercise intensity. The peak intensity corresponded to approximately 85% of maximal oxygen consumption. During this exercise, the heart rate (fc), mean blood pressure (BP) in the brachial artery and mean blood flow velocity (vcc) in the common carotid artery increased as functions of exercise intensity. At the peak exercise intensity, fc, BP and vcc increased by 134.5%, 20.5% and 51.8% over the control levels before exercise (P < 0.01), respectively. The resistance index (RI) and pulsatility index (PI) were determined from the velocity profile and were expected to reflect the distal cerebral blood flow resistance. The RI and PI increased during the graded exercise, but tended to decrease at the highest levels of exercise intensity. As vcc increased with increases in exercise intensity it would be expected that cerebral blood flow would also increase at these higher intensities. It is also suggested that blood flow velocity in the cerebral artery does not proportionately reflect the cerebral blood flow during dynamic exercise, since the cerebral blood flow resistance changes.

Blood Flow Velocity↗
PubMed1995

Butyltins in muscle and liver of fish collected from certain Asian and Oceanian countries.

Concentrations of butyltin residues were determined in muscle tissue of fish collected from local markets and sea food shops in India, Bangladesh, Thailand, Indonesia, Vietnam, Taiwan, Australia, Papua New Guinea and the Solomon Islands. Contamination levels were determined in the Asia-Pacific region and human exposure was estimated. Similarly, corresponding liver samples of fish muscle collected in Australia, Papua New Guinea and the Solomon Islands were analyzed to obtain information on partitioning of butyltin compounds between muscle and liver tissues. Butyltin compounds were detected in most of the samples which suggested widespread contamination in Asia and Oceania. The concentrations of butyltin compounds were, on average, an order of magnitude higher in liver than in muscle. Residue concentration of Sigmabutyltin in liver was found to be correlated significantly (p < 0.02) with those in muscle. Intensive ship-scrapping activities, sewage disposal and antifouling paints are considered the major sources of butyltins in this region. Increased proportions of MBT over DBT and TBT in samples from most locations indicated degradation of TBT to MBT in fish tissues during storage at 4 degrees C in the dark over 1-2 years. The possibility that fish have been subject to increased exposure to MBT and that TBT degrades to MBT quite rapidly in tropical environments are also considered. Butyltin concentrations in fish from Asia and Oceania were lower than those reported for Japan, Canada and the USA. Although the number of samples analyzed from each country was small, it is tentatively suggested that intake of butyltins by humans via consumption of fish in these countries was < 25% of the tolerable daily intake of 250 ng kg bw(-1) day(-1). To our knowledge, this is the first study reporting on butyltin pollution in developing Asian countries.

Journal Article↗
PubMed1995

Activation of prothrombin by factor Xa bound to the membrane surface of human umbilical vein endothelial cells: its catalytic efficiency is similar to that of prothrombinase complex on platelets.

Upon incubation of human prothrombin with factor Xa bound to human umbilical vein endothelial cells (HUVEC) (0.5-0.6 fmol factor Xa/10(5) cells), three bonds at Arg273-Thr274, Arg286-Thr287, and Arg322-Ile323 were cleaved, yielding and releasing fragment 1-2 and a degraded form of alpha-thrombin, but not meizothrombin, into the fluid phase. The apparent Km for prothrombin and the Vmax were 0.25 +/- 0.07 microM and 210 +/- 40 fmol thrombin/min/10(5) cells, respectively. For the maximally bound factor Xa, the calculated catalytic efficiency (kcat = 6-7 s-1) was similar to those reported for the prothrombinase complex formed on the phospholipid vesicles and natural membrane surfaces. The prothrombin derivatives lacking the 10 gamma-carboxyglutamic acid (Gla) residues-containing region were not activated by the cell-bound factor Xa. The activation rate of prothrombins with Gla residues variously modified to gamma-methyleneglutamic acids was reduced in accordance with the number of modified residues. For the inhibition of prothrombin activation, intact fragment 1 was needed; the Gla-domain alone did not affect the reaction. Binding of monoclonal antibodies to the region of 1-48 or the kringle 1 region of prothrombin also interfered with the prothrombin activation. Prothrombin activation on the surface of HUVEC appeared to proceed via formation of a cellular prothrombinase complex composed of phospholipids of HUVEC membrane, endogenous factor Va, factor Xa, and prothrombin. The Gla-domain and kringle 1 regions are indispensable for the molecule to serve as an effective substrate for the cell-bound factor Xa.

Amino Acid Sequence↗
PubMed1995

Effects of lansoprazole on gastric ulcer healing and mucin content.

The effect of lansoprazole, a new benzimidazole proton pump inhibitor, on the relationship between ulcer healing and changes in mucin content was studied in gastric ulcer patients. Twenty-one outpatients with active gastric ulcers received lansoprazole 30 mg once daily given in the morning for 8 weeks. The gastric mucin content was examined by HPLC analysis of hexosamines in gastric biopsy specimens obtained from the lesser curvature of the pylorus and the greater curvature of the upper body. The ulcer healing rate for lansoprazole was 85.7% at 8 weeks. The mucin content of both mucosal regions significantly decreased to approximately 70% (pylorus 70.9%; upper body 74.7%) of the value before drug treatment. The results of this study demonstrate that 30 mg lansoprazole once daily is remarkably effective in healing gastric ulcers because of its potent acid suppression. It appears that acid inhibition is the primary factor in initial treatment. However, maintaining an altered gastric mucosal defense mechanism may have implications for the long-term treatment of gastric ulcers.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

Reconstitution of an iron-sulfur cluster with bound sulfur: a possible source of acid-labile sulfur in biological systems.

The reconstitution of the iron-sulfur cluster of spinach ferredoxin was examined in vitro using low and high molecular bound sulfur components as sulfur donors. Bound sulfur was rapidly converted to acid-labile sulfur to form an iron-sulfur center in the presence of dihydrolipoate and iron. Reconstitution yields of above 95% were obtained with cystine trisulfide (CT, 0.25 mM) and sulfur-bound albumin (SBA, 1.0 mM) at 37 degrees C, pH 7.3, following 60 min incubation. Spectroscopic features and biological activity of the reconstituted ferredoxin were identical to those of the native holo-protein. The acid-labile sulfur content found in the isolated reconstituted ferredoxin was 2 atoms/mol protein, similar to the theoretical value. A possible role for bound sulfur in mammalian cells is indicated and discussed.

Circular Dichroism↗
PubMed1995

Primary structure of an allergenic peptide occurring in the chymotryptic hydrolysate of gluten.

An allergenic peptide was isolated from the chymotryptic hydrolysate of gluten by gel filtration and HPLC. The primary structure of the peptide was determined as Ser-Gln-Gln-Gln-Gln- Pro-Pro-Phe-Ser-Gln-Gln-Gln-Pro-Pro-Phe-Ser-Gln-Gln-Gln-Gln-Pro-Pro-Phe- Ser- Gln-Gln-Gln-Gln-Pro-Pro-Phe-Ser-Gln-Gln-Gln-Pro-Pro-Phe. The amino acid sequence similarity shows that the peptide originated from a low-molecular-weight glutenin chain.

Allergens↗
PubMed1995

Flow cytometric analysis and immunohistochemistry of delayed-type hypersensitivity responses in mice immunized with rat hepatocytes.

Delayed-type hypersensitivity (DTH) responses to rat hepatocytes (HCs) in mice were investigated by flow cytometric analysis and immunohistochemistry with monoclonal antibodies directed against murine class II, CD4, and CD8 antigens. Mice were immunized subcutaneously (s.c.) with 10(6) rat HCs (referred to as s.c.-immunized mice), and control mice were injected s.c. with sterile Hanks' solution (non-immunized mice). Four days later, 10(5) rat HCs were injected into the footpad of s.c.-immunized mice and non-immunized mice. The DTH response in s.c.-immunized mice significantly increased after challenge when compared to that in non-immunized mice. The numbers of class II+, CD4+, and CD8+ cells in the footpad, and CD4+ and CD8+ cells in the inguinal lymph node of s.c.-immunized mice significantly increased during the DTH response. An increase in the number of CD4+ cells in the footpad of s.c.-immunized mice after challenge was more significant than that of non-immunized mice. The number of CD4+ cells increased more markedly in the footpad of s.c.-immunized mice as compared to that of CD8+ cells. Furthermore, immunohistochemical studies of the footpad of s.c.-immunized mice showed more severe infiltration of CD4+ cells rather than CD8+ cells at the injection site of rat HCs. These results suggest that the DTH response in the footpad of mice immunized with rat HCs is associated with severe infiltration of CD4+ cells.

Animals↗