Biomedical subjects

K Kitamura

Publications and source records attributed to K Kitamura.

At least 1,063 records · Page 59Linked to original sources

PubMed1986

Isotype-specific immunoregulation. Evidence for a distinct subset of T contrasuppressor cells for IgA responses in murine Peyer's patches.

The ability of murine Peyer's patch (PP) T contrasuppressor cells (Tcs) to reverse oral tolerance to the T cell-dependent (TD) antigen SRBC was studied both in vivo and in vitro. C3H/HeJ mice given SRBC orally for 4 wk are not rendered tolerant to this antigen and were used as a source of PP Tcs cells for adoptive transfer to identically treated, orally tolerized C3H/HeN mice. Transfer of 10(4) or 5 X 10(4) V. villosa-adherent PP T cells resulted in splenic IgM, IgG, and mainly IgA responses in C3H/HeN mice challenged systemically with SRBC. The T cell responsible was Lyt-1+, 2-, L3T4-, I-JK+ and V. villosa lectin-adherent, all characteristics of mature effector Tcs cells. This C3H/HeJ PP Tcs cell subset was also effective when added to in vitro cultures of tolerized spleen cells derived from SRBC-fed, C3H/HeN mice. Interestingly, C3H/HeJ PP Tcs cells restored mainly IgA responses when transferred in vivo or when added to suppressed C3H/HeN splenic cultures. Comparison of the functional activity of Tcs cells derived from spleen or PP of orally immunized C3H/HeJ mice revealed that splenic Tcs cells supported responses of all 3 isotypes; however, PP Tcs cells yielded three-fourfold higher IgA responses, when compared with IgM or IgG anti-SRBC responses. Adherence of C3H/HeJ PP Tcs to an Fc alpha R+ T cell line derived from IgA-specific Th cells resulted in a nonadherent cell fraction that potentiated only IgM and IgG responses, while bound Tcs cells preferentially supported IgA responses. These results suggest that murine PP contain IgA-specific Tcs cells that allow IgA response induction in the presence of Ts cells that mediate oral tolerance.

Administration, Oral↗

PubMed1986

Importance of antibody isotype in monoclonal anti-idiotype therapy of a murine B cell lymphoma. A study of hybridoma class switch variants.

An initial panel of four syngeneic monoclonal antibodies directed against the idiotype of a murine B cell lymphoma was used to treat this tumor in vivo. The antibody in the panel of the IgG2a isotype was more effective in treatment than the other antibodies, which were of the IgG1 and IgG2b isotypes. To independently assess the role of antibody isotype in mediating antitumor effects, switch variant hybridoma families were isolated from the hybridomas secreting the less effective IgG1 and IgG2b antibodies. A family isolated from an IgG1-secreting parent consisted of IgG1-, IgG2b-, and IgG2a-secreting members, and an IgG2a variant was isolated from an IgG2b-secreting parent for another family. Antibody members of each family differed only in heavy chain composition and were the same with respect to their light chains and their affinity and specificity for idiotype. The IgG2a members of both families were superior to the other members in inhibiting tumor growth with an order of effectiveness of IgG2a greater than IgG1 greater than IgG2b. These in vivo results paralleled the abilities of these different isotype antibodies to mediate antibody-dependent cellular cytolysis in vitro. For the IgG2b----IgG2a family, in vivo treatment with the IgG2a member given i.p. after i.p. tumor challenge at one-tenth the dose of the IgG2b member was still superior to the latter. At one-hundredth the dose of the IgG2b, the IgG2a was still superior to the latter when the antibodies were given i.p. and tumors subcutaneously. These data and those showing that the clearance of these antibodies from the serum differed in only a relatively minor way indicate that the IgG2a antibodies in this system had greater antitumor effects primarily by virtue of their greater capacity for host effector interaction.

Animals↗

PubMed1986

Radiological analysis of hemifacial spasm with special reference to angiographic manifestations.

Fifty-one patients with hemifacial spasm secondary to facial nerve compression by normal appearing, elongated, tortuous and/or dilated arteries, were treated by microsurgical neurovascular decompression. Post-operatively, 91% of 44 of these patients with one to six year postoperative follow-ups were satisfactory. The angiographic findings showed significant increase in the number of common trunk anomalies. Variations of the anterior and posterior inferior cerebellar and vertebral arteries are discussed in relation to nerve compression.

Adult↗

PubMed1986

Actions of quinidine and apamin on after-hyperpolarization of the spike in circular smooth muscle cells of the guinea-pig ileum.

The effects of quinine and quinidine on membrane potential and action potential were investigated in circular smooth muscle of the guinea-pig ileum and the findings compared with the actions of apamin. In addition to results obtained from microelectrode experiments, the actions of quinidine and apamin on membrane currents were assessed using the single cell voltage clamp method. Quinine (above 0.2 mmol/l) and quinidine (above 0.08 mmol/l) depolarized the membrane, increased the membrane resistance and blocked generation of the after-hyperpolarization of the spike. Higher concentrations of both agents reduced the amplitude of the action potential and further depolarized the membrane. Quinidine and quinine possessed much the same action, with the former being more potent than the latter. Apamin, an inhibitor of the Ca-dependent K current, did not inhibit the after-hyperpolarization of the spike and had no effect on the membrane potential. In voltage clamp experiments, a depolarizing pulse (above -30 mV from -60 mV; 200 ms duration) elicited an inward current, followed by an outward current. With application of 2.5 mmol/l Mn instead of Ca, the outward current was subclassified into the Mn sensitive (Ca-dependent) and Mn resistant (voltage-dependent) K currents. Apamin (0.1 mumol/l) did not modify membrane currents evoked in the circular muscle cell, while, 0.1 mmol/l quinidine inhibited both the Ca- and voltage-dependent K outward currents, and Ca inward current. Our observation suggest that apamin-insensitive Ca-dependent K channels are present in the smooth muscle membrane and that they probably participate in the falling phase and after-hyperpolarization of the action potential.

Action Potentials↗

PubMed1986

A newly identified Ca2+ dependent K+ channel in the smooth muscle membrane of single cells dispersed from the rabbit portal vein.

We found a new type of Ca2+-dependent K+ channel in smooth muscle cell membranes of single cells of the rabbit portal vein. A slope conductance of the current was 180 pS when 142 mM K+ solution was exposed to both sides of the membrane (this channel was named the KM channel, in comparison to the known KL and KS channels from the same membrane patch; Inoue et al. 1985). This KM channel was less sensitive to the cytoplasmic Ca2+ concentration, [Ca2+]i, but was sensitive to the extracellular Ca2+, [Ca2+]o, e. g. in the outside-out membrane patch, lowering the [Ca2+]o in the bath markedly reduced the open probability of this channel, and also in cell-attached configuration, lowering of the [Ca2+]o using the internally perfused patch clamp electrode device reduced the opening of KM channel. TEA+ (1-10 mM) reduced the amplitude of the elementary current through the KM channel applied from each side of the membrane, but this agent inhibited the KM channel to a greater extent when applied to the inner than to the outer surface of the membrane. Furthermore, this KM channel had a weak voltage dependency, and the open probability of the channel remained much the same within a wide range of potential (from -60 mV to +60 mV). Whereas most Ca2+-dependent K+ channels are regulated mainly by [Ca2+]i and possess a voltage dependency, these properties of the KM channel differed from other Ca2+-dependent K+ channels.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Proliferating potential of folliculo-stellate cells in human pituitary adenomas. Immunohistochemical and electron microscopic analysis.

Folliculo-stellate cells (FS cells) in 40 pituitary adenomas and portions of anterior pituitary adjacent to the tumor in 26 cases were investigated immunohistochemically, using polyclonal antisera to S-100 protein (S-100) and glial fibrillary acidic protein (GFAP). The objective was to clarify the histological behavior of the FS cells. In most pituitary adenomas there were few or no S-100- or GFAP-positive cells, in comparison with numerous positive cells in the parts of the adenohypophyses compressed by adenomas. However, positive FS cells were observed in some types of pituitary adenomas. Growth hormone and prolactin producing adenomas frequently contained significant amounts of FS cells. In non-functioning adenomas, an unique case of FS cell adenoma was present. The adenoma was composed mainly of FS cells and immature glandular cells. The FS cells were sometimes located around follicles containing Periodic acid Schiff-positive material. Therefore, the FS cell adenoma is characterized by S-100- and GFAP-positive FS cells and PAS-positive follicles. In this type of adenoma, FS cells seemed to be the main proliferating component. In parts of the adenohypophyses adjacent to the adenomas, GFAP-positive FS cells were numerous. In the pathological conditions FS cells may possess the potential of reactive proliferation.

Adenoma↗

PubMed1986

High performance liquid chromatography of integral glycoproteins of peripheral nerve myelin.

Peripheral nerve myelin contains a large quantity of integral glycoproteins, such as PO and PASII protein. The present paper reports a fast and sensitive method for separation of these glycoproteins. High performance liquid chromatography (HPLC) with TSK-GEL 3000 SW column in the presence of sodium dodecyl sulfate (SDS) or lithium dodecyl sulfate (LDS) was used. Whereas the separation of PO and PASII was inadequate with low concentrations of the detergent, better separation profiles were obtained with high concentrations (1-2%) of the detergent in 0.1 M phosphate buffer. The two glycoproteins were able to be purified by rechromatography. High concentration of the detergent presumably diminished interaction between these glycoproteins. LSD-phosphate, SDS-lithium citrate or SDS-Tris buffer as an eluent was also compared with SDS-phosphate system. This method will be applicable to the detection and purification of proteins from myelin or other organelles.

Animals↗

PubMed1986

Proliferative activity of meningiomas as evaluated by bromodeoxyuridine uptake examination.

Proliferative activity of meningiomas was examined in 12 consecutive cases by administering bromodeoxyuridine (BrdU) before surgical removal and by immunohistochemical staining of the removed tumours using anti-BrdU monoclonal antibody (anti-BrdU MAb) to detect BrdU-labelled tumour cells. The 12 cases consisted of 6 with a primary tumour and 6 with a recurrent tumour. All of the tumours contained labelled cells and the labelling index (LI) was obtained in each tumour. The highest average LI was 13.6% and the second highest was 9.0% both in recurrent cases of histologically malignant meningothelial meningioma. The high LIs of both cases were thought to correspond well with the rapid recurrence of the tumour. The average LI of a case of recurrent haemangiopericytic tumour was 2.0%, and that of a case of meningioma associated with von Recklinghausen disease was 1.5%. The other 8 meningiomas showed the average LIs ranging from 0.1 to 0.9%, which were considered to be the LIs of usual benign meningiomas. The results of the BrdU uptake examination was considered to reflect well the clinical behaviour of meningiomas. The usefulness of the BrdU uptake examination in brain tumours, which can be employed in the clinical practice without any serious side-effects, is stressed.

Adolescent↗

PubMed1986

Hemangiomas of the central nervous system in Japan: an epidemiological and clinicopathological study with special reference to venous and cavernous malformations.

Our experiences with cerebrovascular malformations in Japanese patients have been reviewed, presenting 29 cases of venous malformation, 30 cases of cavernous angiomas and one case of capillary telangiectasis. We also present the data from the 763 cases of AVM obtained in the cooperative studies which were supported by the Ministry of Health and Welfare of Japan, and discussed the epidemiological and clinicopathological aspects in relation to those reported in the literature. The cooperative studies on these subjects were primarily done in conjunction with the investigation of Moya-Moya disease which is by far frequently found in Japan. Regarding the vascular malformations of the C.N.S., there seem to be no noticeable differences in the epidemiological aspects as seen in Japan and in other countries. It should be stressed also from our experiences that all kinds of vascular malformation, either intracranial or intraspinal, bleed probably more often than we expect. Neurosurgeons should pay more careful attention to these vascular malformations with appropriate concepts of the disease.

Adolescent↗

PubMed1986

Induction of neutralizing antibody against varicella-zoster virus (VZV) by VZV gp3 and cross-reactivity between VZV gp3 and herpes simplex viruses gB.

Glycoprotein gp3 (64K) is one of the major proteins specified by varicella-zoster virus (VZV). This glycoprotein was purified on an immunoadsorbent consisting of monoclonal antibody (clone 8) against gp3 linked to protein A-Sepharose. Rabbits were then immunized with the purified antigen to obtain monospecific antisera against gp3. The monospecific antisera and monoclonal antibody immunoprecipitated polypeptides with the same molecular weights of approximately 64,000 (64K), 106K, and 116K from a lysate of labeled cells infected with VZV. The monoclonal antibodies against gp3 did not have neutralizing activity against VZV, but anti-gp3 monospecific sera neutralized VZV infectivity. The antigenic relation of VZV to herpes simplex virus (HSV) was investigated by the immunofluorescent test, immunoprecipitation followed by analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the neutralizing antibody test with monoclonal antibodies and monospecific antisera. In the indirect immunofluorescent test, the cytoplasm of cells infected with HSV-type 1 or HSV-type 2 was stained with anti-gp3 monospecific antiserum but not with anti-gp3 monoclonal antibodies. This serum also precipitated the polypeptides of HSV-type 1 and HSV-type 2 with molecular weight of approximately 120,000, possibly corresponding to gB of HSV-1 or HSV-2, and this immunoprecipitation was blocked by anti-gB monoclonal antibody. However, anti-gp3 monospecific antisera did not neutralize either HSV-type 1 or HSV-type 2 infectivity. These results suggest that gp3 induces neutralizing antibody against VZV and that it also has a cross-reacting antigenic determinant with gB of HSV.

Animals↗

PubMed1986

Chondrosarcoma arising from the falx cerebri.

A chondrosarcoma arising from the falx cerebri in a 15-year-old boy is reported. The patient had been suffering from convulsive seizures and weakness of the limbs on the left side for about 7 months prior to admission. A high-density mass attached to the falx was demonstrated by computed tomographic scan. Clinically it was very similar to a falx meningioma, and the final diagnosis was obtained from histopathological examination. The tumor was completely excised at operation, which is extremely important to prevent both local recurrence and distant metastasis.

Adolescent↗

PubMed1986

Spasmodic torticollis caused by vascular compression of the spinal accessory root.

A case of spasmodic torticollis in a 27-year-old man cured by vascular decompression of the spinal accessory root, without any nerve sectioning, is presented. The nerve compression was produced by the posterior inferior cerebellar artery originating from the vertebral artery at the C-1 level, and was released by transposing the artery from the nerve root, using the divided dentate ligament. The patient was completely free from symptoms after a follow-up period of 3 years. The possible causal importance of nerve compression in spasmodic torticollis is emphasized.

Accessory Nerve↗

PubMed1986

Hemorrhagic stroke in infancy, childhood, and adolescence.

The authors report on factors influencing the outcome after hemorrhagic strokes in infants, children, and adolescents over a period of 14 years. Their series comprised primary hemorrhage in 24 cases (46.2%), including 5 cases of vitamin K deficiency; arteriovenous malformation in 20 cases (38.5%); intracranial aneurysm and moya-moya disease in 3 cases (5.7%) each; and spinal angioma in 2 cases (3.9%). Ten of 52 patients with juvenile hemorrhagic strokes died despite surgical treatment. These fatal cases involved an intraparenchymal hematoma with ventricular casts, and unilateral hydrocephalus suggesting acute, uncontrollable intracranial hypertension. The "child's biologic plasticity" plays an important role in the favorable prognosis in infants, children, and adolescents with hemorrhagic strokes. On the contrary, cases with intraventricular hemorrhage due to any pathologic condition have an unfavorable prognosis.

Adolescent↗

PubMed1986

Mandibular ameloblastoma with intracranial extension and distant metastasis.

A case of mandibular ameloblastoma which invaded intracranially through the skull base and developed distant metastasis to the femur is reported. The intracranial extension of the tumor was partially removed three times and the metastasis of the femur was curetted. The remaining tumor temporarily responded to chemotherapy, but the patient died of intracranial tumor regrowth. The period from the initial treatment of the mandibular tumor to death was 21 years.

Adult↗

PubMed1986

Postoperative plasma GH levels and restoration of GH dynamics in acromegalic patients surgically treated by the transsphenoidal approach.

In 44 patients with acromegaly treated by transsphenoidal pituitary microsurgery, the relationship between changes in pre- and post-operative GH dynamics and postoperative fasting plasma GH levels was examined to clarify which is the optimal approach for evaluating postoperative removal of the tumour. TRH, LHRH and bromocriptine tests, which act directly on the pituitary somatotroph, and the oral glucose tolerance test (oGTT) and insulin tolerance test (ITT), which act via hypothalamus, were carried out pre- and post-operatively. Abnormal responses postoperatively were found in most patients with fasting postoperative plasma GH over 5 ng/ml. In 24 patients with postoperative fasting plasma GH level of 5 ng/ml or below, 7 of 17 (41%) showed abnormal responses in the TRH test, 2 of 5 (40%) in the LHRH test and 3 of 13 (23%) patients in the bromocriptine test. All patients with a fasting plasma GH level less than 10 ng/ml, except for those with panhypopituitarism, showed normal responses to ITT and the paradoxical increases with the oGTT were absent. These results indicate that abnormal responses caused by a direct action on adenoma cells do not necessarily disappear even when the fasting plasma GH level is below 5 ng/ml. Abnormal responses caused by indirect actions, through the hypothalamus, disappear when the level is less than 10 ng/ml.

Acromegaly↗

PubMed1986

Membrane currents recorded from a fragment of rabbit intestinal smooth muscle cell.

Properties of ionic currents in smooth muscle membranes of the longitudinal muscle layer of the rabbit ileum were investigated using the single electrode voltage clamp method. In the present experiments, this method was applicable only to the smooth muscle ball (fragment) and not for the dispersed whole cell, because of incompleteness of the voltage clamping. A voltage step elicited a transient inward current followed by an outward current. This outward current was partly inhibited by Mn2+ or nisoldipine or by a reduction in the extracellular [Ca2+] ([Ca2+]o). Tetraethylammonium (TEA) reduced the delayed outward current in a dose-dependent manner, but 50 mM TEA did not produce a complete block of a residual current. When the pipette contained K+-free (Cs+ with TEA+) solution, the residual outward current was abolished. The inward current was elicited at -30 mV (holding potential of -60 mV) and reached the maximal value at +10 mV; the polarity was reversed at +60 mV. This inward current depended on the [Ca2+]o and was blocked by Mn2+ or nisoldipine. Ba2+ also permeated the membrane, and the inward current evoked by Ba2+ was also blocked by Mn2+ or nisoldipine. Reduction of [Na+]o in a solution containing 2.4 mM Ca2+ neither modified the current-voltage relation nor the decay of the inward current, but when [Ca2+]o was reduced to below 1 microM, Na+ permeated the membrane and was blocked by nisoldipine. In conclusion, ionic currents were recordable from the fragmented ball of the longitudinal muscle of rabbit ileum. There were at least two K+ currents as the outward current (Ca2+-dependent K+ and delayed K+ currents) and a Ca2+ current as the inward current. The property of the Ca2+ channel was similar to that observed with other preparations.

Animals↗

PubMed1986

The significance of alpha-subunit as a tumor marker for gonadotropin-producing pituitary adenomas.

We studied gonadotropin hormone alpha-subunit and gonadotropin secretion in four patients with gonadotropin-producing pituitary adenomas. All four patients had elevated plasma alpha-subunit levels, ranging from 2.8-8.5 ng/ml (normal, less than 0.5 ng/ml). alpha-Subunit responses to LHRH were less than those in seven patients with primary gonadal failure. The relative proportions of the gonadotropin and alpha-subunit peaks in one patient were the same before and after LHRH administration, based on gel filtration studies of plasma. The alpha-subunit levels decreased little during testosterone treatment in the two adenoma patients so treated. Immunohistochemical study of the adenomas from two patients demonstrated definite staining with alpha-subunit and gonadotropin antisera. Elevated plasma levels of alpha-subunit and its relative unresponsiveness to LHRH stimulation or testosterone suppression suggest that the alpha-subunit originated in tumor tissue and that its measurement is useful for the diagnosis of a gonadotropin-producing tumor in patients with elevated plasma levels of LH and/or FSH.

Adenoma↗

PubMed1986

Acute subdural hematoma with rapid resolution in infancy: case report.

An infant who suffered acute subdural hematoma due to minor head trauma twice in a short period is presented. Each subdural hematoma, showing high density on computed tomographic scanning, resolved with unusual rapidity, resulting in full recovery after nonsurgical management. The mechanism of this rapid resolution of each hematoma was thought to be participation of cerebrospinal fluid secondary to a tearing of the arachnoid membrane.

Acute Disease↗