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Biomedical subjects

H Kobayashi

Publications and source records attributed to H Kobayashi.

At least 379 records · Page 21Linked to original sources
PubMed2000

Idiopathic gastric perforation in neonates and abnormal distribution of intestinal pacemaker cells.

BACKGROUND/PURPOSE: The etiology of idiopathic gastric perforation (IGP) in neonates is unclear. Interstitial cells of Cajal (ICC) express tyrosine kinase receptor C-kit, and act as gastrointestinal pacemaker cells. Stem cell factor (SCF) is a C-kit ligand and plays an important role in immune system homeostasis in the gastrointestinal tract. The authors hypothesized that abnormal distribution of ICC or SCF in the gastric wall (ie, abnormal motility or impaired immunity) could predispose the stomach to IGP. METHODS: Stomachs obtained at postmortem from neonates who died of IGP (n = 7) and other causes (control group; n = 10) were used. Biopsy sections were taken at random from various sites in the stomach, including macroscopically intact areas, and labeled immunohistochemically using antibodies to C-kit(a marker for ICC) and SCF. RESULTS: In all control specimens, ICC were present between the muscle layers and around the myenteric plexuses of the stomach wall. In contrast, ICC were absent in all biopsy sections from 3 of the 7 IGP stomachs. In the remaining 4 IGP stomachs, there were fewer ICC in the muscle layers compared with controls, and ICC were absent around the myenteric plexuses. The distribution of SCF immunoreactivity in IGP and control specimens was similar. CONCLUSION: The findings suggest that a lack of ICC (ie, gastric hypomotility) may be implicated in the etiology of IGP in neonates.

Analysis of Variance↗
PubMed2000

Reversible dimerization of 20 kilodalton human growth hormone (hGH).

A noncovalent dimer of the 22 kilodalton human growth hormone (22 K-hGH) is known to have diminished somatogenic activity compared with monomeric 22 K-hGH. In the present study, we examined the biological activity and physicochemical behaviour of a noncovalent dimer of the 20 kilodalton human growth hormone (20 K-hGH), an isoform of 22 K-hGH. Analysis of the equilibrium between monomeric and associated forms revealed that the associated 20 K-hGH was present in the dimeric form in aqueous solution. The kinetics of dimerization in rat plasma followed the theory of dissociation-association equilibrium, and more than 99% of 20 K-hGH molecules existed as a monomer in the equilibrium state at the physiological hGH concentration. Analysis of the pharmacokinetics showed that the ratio of the administrated dimer in rat circulation decreased from 43% to less than 4% in 2 h. A preparation of noncovalent dimeric 20 K-hGH had essentially the same degree of biological potency as that of a monomer in both in vitro and in vivo bioassays. In conclusion, dimerization of 20 K-hGH is reversible both in vitro and in vivo and a noncovalent dimer can function as a pharmaceutically active component of a 20 K-hGH preparation, in contrast to a 22 K-hGH preparation.

Animals↗
PubMed2000

CNTFR alpha alone or in combination with CNTF promotes macrophage chemotaxis in vitro.

Microchemotaxis chambers were used to investigate whether one aspect of ciliary neurotrophic factor CNTF's role as a lesion factor might be to promote the initial early recruitment of macrophages, which express the signal transducing receptor components, gp130 and LIFRbeta. CNTFRalpha alone, or in combination with CNTF, elicited concentration-dependent macrophage chemotaxis that was inhibited by a neutralizing gp 130 antibody. IL-6, but not LIF, similarly promoted gp 130-dependent macrophage chemotaxis. Stimulation of macrophages with either CNTFRalpha in combination with CNTF or IL-6 alone resulted in tyrosine phosphorylation of an approximately 130 kD protein, presumed to be gp130. Macrophage chemotaxis induced by the combination of CNTFRalpha and CNTF was inhibited in a dose-dependent fashion by wortmannin, LY294002 or PD98059, suggesting the involvement of the phosphoinositide-3 kinase and mitogen-activated protein kinase signaling proteins. As CNTFRalpha and CNTF are present, or have immediate access to nerves after injury, these data point to the possibility that this soluble receptor alone or in combination with its ligand may promote the initial early recruitment of macrophages in vivo.

Androstadienes↗
PubMed2000

Antifungal, antimitotic and anti-HIV-1 agents from the roots of Wikstroemia indica.

With guidance of Pyricularia oryzae bioassay, daphnoretin (1), (+)-nortrachelogenin (2), genkwanol A (3), wikstrol A (4), wikstrol B (5) and daphnodorin B (6) were isolated from the roots of Wikstroemia indica. Compounds 1-6 induced morphological deformation of P. oryzae mycelia with MMDC values of 68.4 +/- 1.3, 31.3 +/- 1.8, 45.8 +/- 0.5, 70.1 +/- 2.4, 52.3 +/- 0.9 and 73.7 +/- 1.6 microM, respectively. Compounds 3-6 showed moderate activity against microtubule polymerization with IC50 values of 112 +/- 4, 131 +/- 3, 184 +/- 6 and 142 +/- 2 microM in vitro, respectively. Compounds 2, 3, 5 and 6 were moderately active against HIV-1 in vitro. The findings of bioactivity of 1-6 support the antifungus, antimitosis and anti-HIV-1 uses for W. indica roots.

Anti-HIV Agents↗
PubMed2000

Fibrin D-dimer in thrombogenic disorders.

Measurement of D-dimer (fibrin degradation product) is important for determining not only the activation of fibrinolysis but also the severity of a hypercoagulable state. However, fibrin degradation products are in variable, and the reactivity to cross-linked fibrin degradation products produced during fibrin degradation differs depending on the kind of antibody used against D-dimer. In patients with disseminated intravascular coagulation or earthquake-induced mental and physical stress and in patients after percutaneous transluminal coronary angioplasty, all of which are associated with acute fibrin formation and degradation, some discrepancies between two methods of D-dimer detection, automated latex agglutination assay (LPIA) and enzyme-linked immunosorbent assay (Stago), were found. No discrepancies in persistent fibrin formation and degradation were found among the healthy elderly, patients with lacunar stroke, and patients with coronary artery disease, almost all of whom had levels under 5.0 microg/mL, as determined by both methods. Evidence of persistently increased intravascular coagulation and fibrin turnover in patients with atherosclerotic disease was found. The cleavage of cross-linked fibrin by plasmin results in a production of fibrin degradation products, mostly contained D-dimer domains. Although the clinical utility of D-dimer can be achieved by their detection with specific antibodies, measurement of D-dimer as high-molecular-weight fragments may be useful to determine whether patients will undergo further fibrin degradation. When intermediate products of the degradation process need to be assessed, D-dimer level measurement by LPIA may serve as a suitable marker for ongoing fibrinolysis.

Adult↗
PubMed2000

Synchronous development of disseminated superficial porokeratosis and hepatitis C virus-related hepatocellular carcinoma.

Immunosuppression and transplantation have been reported to induce porokeratosis (PK), especially its variant, disseminated superficial PK (DSP). On the other hand, there is ample evidence of a relationship between hepatitis C virus (HCV) infection, liver cirrhosis (LC), and hepatocellular carcinoma (HCC). We report 3 cases of DSP in which the outbreak of DSP was suspected to have occurred during the development of HCC in patients with HCV-positive LC. The patients had undergone ultrasonographic study regularly, and no signs of malignancy had been found before the development of DSP. Their outbreaks of DSP were very acute, and the period between the development of DSP and diagnosis of HCC ranged from 2 to 6 months. The association of HCV-related HCC and DSP has never been previously reported. HCV-induced immunomodulation or its effect on the p53 system may be the basis for this type of association. It is necessary to consider development of HCC whenever DSP is found in HCV-positive patients. DSP may be a new paraneoplastic dermadrome.

Aged↗
PubMed2000

Competitive reverse transcription-polymerase chain reaction assay for quantification of human multidrug resistance 1 (MDR1) gene expression in fresh leukemic cells.

We have analyzed MDR1 gene expression in 69 clinical samples obtained from 64 patients with leukemic hematologic malignancies by using a competitive reverse transcription-polymerase chain reaction assay with a heterologous competitor RNA. To exclude a false-positive result caused by concomitant normal lymphocytes that physiologically express MDR1, in samples we determined a cut-off value of 8 amol MDR1 transcript per microgram of RNA by simultaneous measurement of rhodamine 123 dye efflux either in lymphocyte or gated leukemic cell populations. Consequently, 23 of 69 samples were concluded to be MDR1-positive in leukemic cells per se. The MDR1 expression rate was significantly correlated with factors such as a history of preceding chemotherapy, elder age of the patient, and certain disease types (eg, leukemia progressed from myelodysplastic syndrome). Moreover, the complete response rate after chemotherapy was significantly higher in MDR1-negative patients than in MDR1-positive patients (52% vs 17%, respectively; P = .01). The assay established will enable the quantification of MDR1 gene expression in blood samples from patients with leukemic hematologic malignancies and will be applicable to clinical laboratories as a routine test.

Adolescent↗
PubMed2000

The relationship between the degree of disk displacement and ability to perform disk reduction.

OBJECTIVE: To evaluate the difference in temporomandibular joint (TMJ) disk position between reducible and permanently displaced disks. STUDY DESIGN: We found 182 joints with disk displacement (83 with reduction and 99 without reduction) that were available for the study. The disk position was estimated by using magnetic resonance imaging. RESULTS: There was a statistically significant difference between them with the permanently displaced disks being located more anteriorly. When a comparison was made in the disks as to which degree of displacement was moderate, a difference of disk position at either the medial or lateral depth of the TMJ was observed. CONCLUSION: It was suggested that the permanently displaced disks are located more anteriorly than the reducible displaced disks. When the disk displacement was moderate, disk reduction was influenced by less disk displacement at either the medial or lateral part of the TMJ.

Adolescent↗
PubMed2000

Analysis of the proliferative potential of tumor cells after stereotactic radiosurgery for recurrent astrocytic tumors.

We analyzed the effectiveness of stereotactic radiosurgery (SRS) for recurrent astrocytic tumors histologically. Five patients were followed by pathological examination after radiosurgery treatment of recurrent astrocytic tumors. Histological diagnoses at the time of the last operation before SRS were Daumas-Duport grade II in two patients and grade IV (glioblastoma) in three patients. No histological diagnoses at the time of SRS were identified in any patients. Contrast enhanced lesions enlarged gradually on magnetic resonance (MR) images after SRS, and local control by SRS was judged as progressive disease radiologically in all patients. Four of five patients received re-operation after SRS, and the other patient died without re-operation and underwent post-mortem examination. After SRS, Ki-67 labeling indices (LIs) of recurrent astrocytomas initially diagnosed as grade II were 2.6% and 1.1%. These LIs were relatively lower than those of the control group of patients with recurrent grade II astrocytomas that were not treated by SRS. Ki-67 LIs of three glioblastomas after SRS were 23.5%, 18.6%, and 17.8%. These LIs were significantly lower than those before SRS (2.3%, 4.5%, and 0.9%). In the autopsy case, there was a significant difference between the LI of tumor cells in the radiosurgically treated region (0.9%) and that in the untreated region (29.2%). These results suggest that the proliferative potential of malignant astrocytic tumors in the radiosurgically treated area is reduced after SRS, and that radiological enlargement of enhanced lesions on MR images is due to propagation of the residual tumor cells that were not covered by radiosurgical target volume or to radiation necrosis. SRS may be a useful therapeutic tool in multidisciplinary treatment of malignant gliomas.

Adult↗
PubMed2000

Changes in expression of mRNAs in the gerbil hippocampus following transient forebrain ischemia.

The phenomenon of delayed neuronal death in CA1 neurons following brief duration of global ischemia has eluded definitive explanation. Using a differential display technique, we examined changes in expression of mRNAs in the hippocampus following 5-min cerebral ischemia in Mongolian gerbils. Under pentobarbital anesthesia, gerbils were sacrificed by decapitation at 6 h (n = 20) and 2 days (n = 20) after ischemia, and sham-operated gerbils (n = 20) were sacrificed at 6 h after surgery. Total RNA was isolated from the hippocampal samples in each group for the differential display analysis. The mRNAs were classified into three patterns; gradual disappearance, decrease and recovery, and new appearance. Representative mRNAs in three patterns were subcloned and sequenced partly. An mRNA in the gradual disappearance pattern showed homologous with neuronal pentraxin. In situ hybridization and Northern blot analyses of neuronal pentraxin revealed the gradual disappearance pattern. An mRNA in the decrease and recovery pattern showed homologous with 14-3-3 protein gamma-subtype, and an mRNA in the new appearance pattern showed no homology in the data base. The differential display analysis is a useful technique with which to investigate changes in expression of mRNAs following transient cerebral ischemia. The novel mRNA may be involved in the treatment of cerebral ischemia. Further studies are necessary for this point.

14-3-3 Proteins↗
PubMed2000

Hard-copy versus soft-copy with and without simple image manipulation for detection of pulmonary nodules and masses.

PURPOSE: To compare interpretation performance on soft-copy presentations, with and without simple image manipulation, and on unmodified hard-copy presentations with regard to detection of pulmonary nodules and masses. MATERIAL AND METHODS: Fifty chest digital radiograph combinations of patients with a total of 60 nodules, 32 of which were 2.0 cm in diameter, were selected for the study. Three readers evaluated three separate image formats: unmodified hard- and soft-copies, and soft-copies with simple image manipulation of lung and mediastinum window settings, and zooming. The screen display was 1600 x 1200 pixels with 8 bits/pixel. RESULTS: The sensitivity, accuracy, detectability, and Az value of the soft-copy systems were clearly inferior to hard-copy evaluation. The mean Az values were 0.921 for unmodified hard-copy, 0.820 for image-manipulated soft-copy, and 0.781 for unmodified soft-copy. CONCLUSION: Soft-copy interpretations were not as sensitive in detecting pulmonary nodules and masses as hard-copy evaluation.

Adult↗
PubMed2000

Well-differentiated liposarcoma of the hand. Case report.

Malignant lipomatous tumours of the hands are extremely rare. A 62-year-old man complained of an enlarging, soft, painless mass in his left hand. Magnetic resonance imaging showed a fatty tumour with irregular septa, and an incisional biopsy showed it to be a well-differentiated liposarcoma. The tumour was resected en bloc and he had a course of external beam radiotherapy. Apart from a slight reduction in grip strength he was well 15 months later with no sign of recurrence.

Hand↗
PubMed2000

Morphometry of the head of the caudate nucleus in patients with velocardiofacial syndrome (del 22q11.2).

UNLABELLED: Velocardiofacial syndrome (VCFS) is a chromosomal anomaly syndrome characterized by multiple congenital malformations, including cleft palate and cardiac anomalies. Many patients have attention-deficit (hyperactivity) disorders (AD[H]D) in childhood and schizophrenia in adulthood. We reviewed cranial magnetic resonance imaging (MRI) scans with particular attention to the head of the caudate nucleus and found that in control subjects, the head of the caudate was larger on the left than on the right, whereas VCFS patients showed a reversed right > left pattern or no significant asymmetry. A similar right > left asymmetry or a lack of this asymmetry has been reported in patients with AD(H)D. CONCLUSIONS: These results suggest a common pathophysiological mechanism of behavioural and cognitive problems in patients with AD(H)D and those with VCFS.

Abnormalities, Multiple↗
PubMed2000

Prevention of radiation-induced mammary tumours in rats by combined use of WR-2721 and tamoxifen.

PURPOSE: This investigation evaluated the inhibitory effect of S-2-(3-aminopropylamino)-ethylphosphorothioic acid (WR-2721) against the initiation of mammary tumourigenesis by irradiation, and the antipromotion activity of tamoxifen in the development of radiation-initiated mammary tumours. MATERIALS AND METHODS: Lactating rats were injected with WR-2721 and then irradiated with gamma-rays (1.5 Gy) at day 21 of lactation. The rats were divided into three groups 1 month after irradiation and were implanted with a pellet either of cholesterol as an inert control, diethylstilbestrol (DES) as a tumour-promoting agent, or DES combined with tamoxifen. For the control experiments, non-irradiated and irradiated rats receiving saline instead of WR-2721 were treated with a pellet by the same procedures. RESULTS: The highest incidence (85%) for tumourigenesis of mammary glands was observed in the irradiated rats that had been previously injected with saline following treatment with DES Administration of WR-2721 prior to the irradiation significantly decreased the incidence of mammary tumours to 52.2%. The treatment with DES pellets combined with tamoxifen in the irradiated rats previously injected with saline also markedly suppressed the incidence of mammary tumours even further to 4.4%. Also, the development of mammary tumours was completely prevented in the rats treated with WR-2721 prior to irradiation and then implanted with DES pellets combined with tamoxifen. CONCLUSIONS: These results suggest that the administration of WR-2721 prior to irradiation has an inhibitory effect on the initiation phase, resulting in a partial reduction of mammary tumour development, and that the combination of WR-2721 at the initiation phase with tamoxifen at the promotion phase is quite effective in preventing mammary tumourigenesis induced by radiation.

Amifostine↗
PubMed2000

Effects of interferon-alpha on peripheral neutrophil counts and serum granulocyte colony-stimulating factor levels in chronic hepatitis C patients.

Granulocytopenia is commonly observed in interferon-alpha (IFN-alpha) therapy. Granulocyte colony-stimulating factor (G-CSF) has been identified as a primary cytokine that regulates neutrophil production, but the kinetics of G-CSF in IFN-alpha-induced granulocytopenia remains unclear. We investigated the effects of IFN-alpha on serum G-CSF levels and peripheral neutrophil counts (NC) in 15 chronic hepatitis C patients treated with standard-dose (10 MU) recombinant IFN-alpha for 24 weeks by using a chemiluminescent enzyme immunoassay for G-CSF. The time course of change after a single IFN-alpha injection showed that mean serum G-CSF levels and NC increased significantly compared with pretreatment values (p < 0.05), and were statistically correlated (r = 0.914, p = 0.0015). On repeating IFN-alpha administration, this change gradually became unclear, and granulocytopenia occurred, accompanied by a significant increase in serum G-CSF (p < 0.01). Both values reached a plateau within 2 weeks after starting treatment, and recovered rapidly after the cessation of therapy. Although continuous administration of IFN-alpha caused a time-dependent granulocytopenia, our results suggest that a single injection of IFN-alpha would be a potent inducer of G-CSF and NC in vivo as a short-term effect and that there would be negative-feedback regulation between them during long-term IFN-alpha therapy.

Adjuvants, Immunologic↗