Emission of Na atoms from undamaged and slightly damaged NaCl (100) surfaces by electronic excitation.
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Journal Article↗
Biomedical subjects
T Kubo
Publications and source records attributed to T Kubo.
Purification and characterization of ATBP, a novel protein that binds to A/T stretches in three segments of the Sarcophaga lectin gene.
A DNA-binding protein for the Sarcophaga lectin gene, ATBP (A/T-stretches-binding protein) was purified to homogeneity from the nuclear extract of NIH-Sape-4 cells. The molecular mass of ATBP determined under denaturing conditions was 53 kDa, but its native molecular mass estimated by gel-filtration chromatography was 430 kDa, suggesting that it is an octamer of the 53-kDa subunit. This protein bound to at least three DNA fragments from the Sarcophaga lectin gene, two of them are in the 5'-upstream region and the other is in a region containing an intron. These fragments are very AT rich and inlaid with stretches of A or T residues (A/T stretches). ATBP was found to have affinity for poly[d(A-T)]. These results suggest that ATBP binds to A/T stretches in the three DNA fragments from this gene. Furthermore, longer DNA was found to be bound more effectively, suggesting that an octamer of the 53-kDa subunit has multiple binding sites for the DNA fragments and requires a relatively long DNA sequence for binding.
Amino Acid Sequence↗
Mutation of K-ras protooncogene is associated with histological subtypes in human mucinous ovarian tumors.
A series of 57 mucinous and 47 serous ovarian tumors (adenomas, tumors of borderline malignancy, and carcinomas) were examined by polymerase chain reaction-single strand conformation polymorphism analysis and direct sequencing for mutations in codons 12, 13, and 61 of K-ras gene. Higher incidence of K-ras mutations was observed in mucinous tumors compared to serous ones. Mutations were detected in 4 of 30 mucinous adenomas (13%), in 4 of 12 mucinous tumors of borderline malignancy (33%), and in 7 of 15 mucinous carcinomas (46%). Only 1 of 17 serous carcinomas (6%) had a mutation of K-ras in serous ovarian tumors. All mutations identified were in codon 12. Detailed analysis revealed that more K-ras mutations in mucinous adenomas were observed in intestinal type (identified in 4 of 13) than in endocervical type (identified in 0 of 17). Thus, K-ras gene codon 12 mutations in mucinous ovarian adenomas appear to be associated with the occurrence of intestinal type adenomas.
Adenocarcinoma, Mucinous↗
An ischemic opening of the blood-brain barrier may deteriorate brain stem auditory evoked potentials following transient hindbrain ischemia in gerbils.
To clarify the effect of vasogenic brain edema on the brainstem, the relationships between waveform changes in brainstem auditory evoked potentials (BAEP) and blood-brain barrier (BBB) disturbance following transient hindbrain ischemia were investigated. Hindbrain ischemia was induced in gerbils by bilateral occlusion of the vertebral arteries. The animals were divided into three groups subjected to 0, 5, and 30 min of bilateral vertebral occlusion (BVO-0',-5', and -30' groups; n = 4 in each group). Two hours after recirculation, Evans blue (EB) solution was injected into the saphenous vein. The brains were removed after 30 min of circulation, and all areas stained macroscopically by EB were noted and recorded. During hindbrain ischemia, BAEP disappeared within 3 min. In the BVO-5' group, BAEP reappeared and returned to normal within 10 min after reperfusion, whereas in the BVO-30' group, BAEP never returned to normal and finally disappeared within 30 min after reperfusion. In the BVO-5' group, no EB staining was visible. On the other hand, in the BVO-30' group, EB staining was seen in the medial part of the tegmentum in the midbrain in two animals, and around the vestibular nucleus in the lateral parts of the pons in three. These results demonstrate the close relationship between the reversibility of ischemia-induced changes in BAEP and BBB disturbance in the brainstem.
Animals↗
Excitatory amino acid receptors in the rostral ventrolateral medulla mediate hypertension induced by carotid body chemoreceptor stimulation.
The rostral ventrolateral medulla (RVLM) is involved in the mediation of cardiovascular responses to peripheral chemoreceptor stimulation. To investigate whether excitatory amino acid inputs in the RVLM are related to the responses to chemoreceptor stimulation, we microinjected kynurenate, an amino acid antagonist, unilaterally into the RVLM and examined its effects on the pressor response to stimulation of carotid body chemoreceptors. Male Wistar rats were anesthetized with urethane, paralyzed and artificially ventilated. The carotid chemoreceptors were stimulated with isotonic solutions of inorganic phosphate solution. Stimulation of carotid body chemoreceptors produced increases in blood pressure. Kynurenate injected ipsilaterally but not contralaterally into the RVLM markedly inhibited the pressor response to chemoreceptor stimulation. In rats with spinal transection, stimulation of carotid body chemoreceptors also produced increases in blood pressure. The pressor response in rats with spinal transection was inhibited by intravenous injection of a vasopressin antagonist or by kynurenate injected ipsilaterally into the RVLM. Kynurenate injected into the RVLM inhibited the pressor response to NMDA, AMPA and kainate but not to acetylcholine in intact rats. These findings indicate that excitatory amino acid receptors are involved in mediating the pressor response to carotid body chemoreceptor stimulation in the rat RVLM. It appears that the chemoreceptor stimulation produces an increase in vasopressin release and the enhancement of vasopressin release is also mediated by an increase in excitatory amino acid inputs in the RVLM.
Animals↗
A combined extradural-posterior petrous and suboccipital approach to the jugular foramen tumours.
An approach which improves on the conventional suboccipital craniectomy was used to explore a jugular foramen, a hypoglossal neurinoma, and a tentorial meningioma. A postero-medial mastoidectomy supplemented by the conventional suboccipital craniectomy made it possible to expose the entire sigmoid sinus. Subsequent medial retraction of the exposed sigmoid sinus and continuous dura mater and the extradural removal of petrous bone around the jugular foramen exposed the whole extracranial portion of the tumours. The tumours were totally removed by this approach in which the extradural route corresponded to the extracranial portion of the tumours and the suboccipital route to the intracranial portion. Facial nerve and hearing disturbances, which are frequent complications of the previous approaches, did not occur in our cases. Providing adequate exposure with simple surgical procedures and showing no adverse postoperative sequelae, this approach is most suitable for surgery upon jugular foramen tumours with extracranial extension.
Carotid Artery, Internal↗
Suppressive effect of FK-506, a novel immunosuppressant, against MPTP-induced dopamine depletion in the striatum of young C57BL/6 mice.
Systemic injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is known to damage the dopaminergic nigrostriatal system in C57BL/6 mice. We have investigated the effects of immunosuppressants, FK-506 and cyclosporin A (CsA), on MPTP-induced dopamine (DA) depletion in the striatum of young C57BL/6 mice. 10 days after MPTP treatment (25 mg/kg i.p. given daily, 5 days), DA in the striatum was depleted by 80%. However, pretreatment with FK-506, a novel immunosuppressant, significantly protected MPTP-induced DA depletion in the striatum, but FK-506 itself did not affect the DA content. CsA, another immunosuppressant, also protected MPTP-induced DA depletion. From these results can be seen that immunosuppressants seem to inhibit MPTP neurotoxicity toward nigrostriatal dopaminergic neurons of young C57BL/6 mice.
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
Up-regulation of ERK (MAP kinase) and MEK (MAP kinase kinase) transcription after rat facial nerve transection.
Up-regulation of ERK (extracellular signal-regulated kinase or MAP kinase) and MEK (ERK kinase or MAPK kinase) expression after rat facial nerve injury was demonstrated by in situ hybridization histochemistry and immunohistochemistry. These two enzymes play roles in one of the major intracellular signal cascade pathways involving receptor tyrosine kinase common to growth factor receptors, and transcription factors. Significant increases in ERK1 mRNA levels were observed from day 3 after facial nerve transection, with the highest level of expression from 1 to 2 weeks after the operation. This high level of mRNA expression then decreased gradually to the normal level. ERK1-like immunoreactivity showed a similar time course to that of its mRNA expression; however, the decay profile was more prolonged. The up-regulation of MEK, the ERK kinase/MAPK kinase, was also detected by immunohistochemistry. The protein expression profiles were almost equivalent, but the MEK expression was slightly advanced, suggesting that the observed up-regulation of MEK was not due to that of ERK. The receptor tyrosine kinase signal transduction pathway via MEK-ERK located downstream of growth factor receptors seems vital as a regulator of the synthesis of molecules that play important roles in the recovery process following injury or/and regeneration.
Animals↗
Gene regulation of cyclic AMP-dependent protein kinase subunits (C alpha, beta; RI alpha, beta and RII alpha, beta) in rat facial motoneurons after nerve transection.
In this study we investigated the changes in gene expressions of catalytic (C alpha, beta) and regulatory (RI alpha, beta and RII alpha, beta) subunits of cAMP-dependent protein kinase (PKA) in axotomized facial motoneurons of the rat. Nerve transection induced changes in the expression of C subunit messenger RNAs and RII subunit messenger RNAs. Control facial motoneurons had a high expression of both C alpha and C beta subunit messenger RNAs, but their expression declined after axotomy. The decrease was most pronounced at postoperative week 2 and returned to basal level within postoperative week 4. In contrast, the expression of both RII alpha and beta subunit messenger RNAs, which were low in control facial motoneurons, was increased after axotomy. Enhancement of RII subunits messenger RNAs was apparent during postoperative weeks 1 and 3, and then returned to the basal level. RI alpha, beta subunits messenger RNAs were strongly expressed in normal facial motoneurons, but were not clearly influenced by axotomy. These results indicate an attenuation of total PKA activity in axotomized facial motoneurons. Furthermore, such gene regulation may imply a change of the targets for PKA in facial motoneurons during the process of neurite regeneration.
Animals↗
Up-regulation of GAP-43 (B50/F1) gene expression in vestibular efferent neurons following labyrinthectomy in the rat: in situ hybridization using an alkaline phosphatase-labeled probe.
Growth-associated protein (GAP)-43 plays a significant role in nerve regeneration and synaptic remodeling. We examined the profiles of GAP-43 mRNA expression in vestibular efferent neurons after labyrinthectomy in adult rats, and clearly demonstrated that labyrinthectomy increased GAP-43 expression in these neurons. This finding suggests the ability of vestibular efferent nerves to regenerate after nerve injury.
Alkaline Phosphatase↗
Localization of osteopontin in the otoconial organs of adult rats.
Although it is known that mammalian otoconia consist of calcium bicarbonate and organic materials, none of the protein components have been identified in mammals at the molecular level, and the mechanisms of morphogenesis and calcification of the otoconia is still unclear. In the present study, we demonstrated the presence of osteopontin (OPN) in rat otoconia by using immunohistochemistry, and detected OPN mRNA in the sensory hair cells by a non-radioisotopic in situ hybridization technique. These results indicate that OPN is one of the protein components in rat otoconia and suggest that sensory hair cells are involved in the production of otoconia.
Animals↗
A new class of noninactivating K+ channels from aplysia capable of contributing to the resting potential and firing patterns of neurons.
From the nervous system of Aplysia, we have cloned a new class of noninactivating K+ channels (aKv5.1) that are activated at low voltage and are capable of contributing to the resting potential and firing patterns of neurons. Expression of aKv5.1 in Aplysia neuron R15 revealed that aKv5.1 exerts an unusual control over cell excitability; it increased the resting potential by more than 20 mV and abolished the spontaneous bursting activity of the cell. In its ability to suppress the endogenous rhythm of R15, aKv5.1 differs in its actions from transient, inactivating K+ channels such as aKv1.1a, an Aplysia homolog of Shaker. aKv1.1a shortens the duration of the spike and increases the afterpotential, but does not suppress bursting. Thus, by expressing different classes of K+ channels, it is possible to redesign, in specific ways, the signaling capabilities of specific, identified neurons.
Action Potentials↗
Fetal nucleated cells in maternal peripheral blood after delivery.
OBJECTIVE: The purpose of this study was to determine the frequency of fetal nucleated cells and their serial changes in maternal peripheral blood after delivery. STUDY DESIGN: A total of 135 blood samples were investigated by means of fluorescence in situ hybridization by observing cells with Y chromosomes. Polymerase chain reaction amplifying two different Y-specific fragments were also carried out for genomic deoxyribonucleic acid from the same samples. RESULTS: The mean frequency of the Y-positive cells detected by fluorescence in situ hybridization in mothers who gave birth to male children was about 1 in 17,500 1 day after delivery. The frequency of these cells decreased with time, dropping below detectable levels 3 months after delivery. The frequency estimated by polymerase chain reaction experiments was significant and positively correlated with those found by fluorescence in situ hybridization. CONCLUSION: Fetal nucleated cells in maternal peripheral blood decrease in frequency with time after delivery. These cells disappear from maternal circulation 3 months after delivery in most, if not all, mothers.
Adult↗
Interleukin-2 expanded tumor-infiltrating lymphocytes and their response to preoperative alpha-interferon in patients with renal cell carcinoma.
To determine whether interferon-alpha could augment antitumorigenic effect of the tumor-infiltrating lymphocytes expanded with interleukin-2, we evaluated the properties of interleukin-2 expanded tumor-infiltrating lymphocytes in 24 patients with renal cell carcinoma with or without treatment with interferon-alpha. Tumor-infiltrating lymphocytes containing tumor cells were separated from nephrectomy specimens by enzymatic digestion and Percoll gradient centrifugation, and were cultured in the serum-free medium containing interleukin-2. The number of lymphocytes increased by 10 to 1,000-fold by day 28 of culture. There was no difference in the proliferation of tumor-infiltrating lymphocytes between interferon-alpha treated patients and controls. On day 14 tumor-infiltrating lymphocytes in the treated patients contained significantly more activated cells (HLA-DR+) and suppressor T cells (CD8+11+) than those in the controls. No significant difference was noted, however, in the cytotoxicity of tumor-infiltrating lymphocytes against autologous and allogenic renal cell carcinoma, K-562 or Daudi cells between the experimental and control groups on day 14 or 28. No specific effects on the major histocompatibility antigens, such as modulation of the expression attributable to the preoperative treatment with interferon-alpha, were observed on renal cell carcinoma tissue when determined by immunohistochemical staining. These findings suggest that interferon-alpha does not consistently produce a beneficial effect on interleukin-2 expanded tumor-infiltrating lymphocytes in patients with renal cell carcinoma.
Adult↗
Nonlinear resonance in the time-dependent Hartree-Fock manifold.
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Journal Article↗
Combination of lymphokine-activated killer cells and interleukin-2 in treating metastatic renal cell carcinoma.
OBJECTIVE: To study the properties of lymphokine-activated killer (LAK) cells and the effect of immunotherapy with a combination of autologous LAK cells and interleukin-2 (IL-2) [LAK therapy] in 10 patients with metastatic renal cell carcinoma (RCC). MATERIALS AND METHODS: The LAK cells were generated from peripheral blood lymphocytes (PBL) by incubation in a serum-free medium (AIM-V) supplemented with IL-2 for 4 days and killer cells were administered intravenously twice a week. The LAK cells showed cytotoxicity against allogenic RCC cell lines and augmented NK and LAK activities. Their phenotypes were CD25+, HLA-DR+, CD3+, and CD16+. Furthermore, LAK cells released IFN-gamma, IL-1 beta, and TNF-alpha. The total number of LAK cells administered ranged from 3.8 x 10(9) to 52.6 x 10(9) cells and the total amount of IL-2 ranged from 150 x 10(5) to 900 x 10(5) U. The effect on pulmonary metastasis in response to LAK therapy was studied. RESULTS: The outcome was complete response (1), partial response (1), minor response (2), no change (4) and disease progression (2). Toxic effects were transient and no serious side-effects occurred. Evaluation of host immune parameters indicated that a clinical response was expected in patients with increasing proportions of CD16+, CD25+, CD57+, HLA-DR+ and CD3+DR+ cells among PBL and with augmentation of NK and LAK activities. Brain metastases were detected in three patients during or after treatment. CONCLUSION: LAK therapy appears to be effective in treating some patients with RCC and pulmonary metastasis. The potential for inducing brain metastasis, however, should be taken into account.
Aged↗
Seroprevalence of hepatitis B and C viruses in eastern Nepal.
The seroprevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) in 303 serum samples collected from that apparently healthy population inhabitating different areas in eastern Nepal was studied. Samples were collected at Dharan Municipality, Sunsari85), Pancha Kanya Village Development Committee, Ilam86), Dhankuta Hile, Dhankuta82) and Basantapur Village Development Committee, Tehrathm50). HBsAg and anti-HBsAg antibody was screened by reverse passive haemagglutination (RPHA) and passive haemagglutination (PHA) respectively and positivity was confirmed by enzyme linked immunosorbent assay (ELISA). Anti-HCV antibody was detected by ELISA. None of the samples were positive for HBsAg. Anti-HBsAg antibody was positive in 1.9% (6/303). The positive rate increased with age reaching 25% positivity among the elderly. The anti-HBsAg antibody positivity was 2.35, 2.32, 1.22 and 2.00 in Dharan, Ilam, Dhankuta and Tehrathum respectively Anti-HCV antibody was detected only in one sample (15-year-old boy) collected in Dharan. These findings indicate that the HBV and HCV infections are not active in eastern Nepal.
Adolescent↗
Status of soil-transmitted helminthic infection in Nepal.
A retrospective evaluation of the status of soil-transmitted helminthic infection in Nepal during the period from 1985 to 1992 was conducted at the Parasitology Laboratory, Department of Pathology, TU Teaching Hospital in Kathmandu. An average of 6,537 faecal samples were examined each year for the presence of various types of intestinal parasites. The annual rate of positivity of these samples for soil-transmitted helminthiasis ranged from 18.0 to 36.6%. The annual incidence decreased every successive calendar year in both adults and children, irrespective of sex. Among the various types of helminths, the most common was Ascaris lumbricoides (roundworm), followed by hookworm. The incidence of A. lumbricoides remained constant throughout the study period, while that of other parasites markedly decreased each year.
Adult↗