Search PubMed⌕ Search

Biomedical subjects

H Komatsu

Publications and source records attributed to H Komatsu.

At least 37 records · Page 2Linked to original sources
PubMed2001

Phenanthroindolizidine alkaloids as cytotoxic substances in a Danaid butterfly, Ideopsis similis, against human cancer cells.

We previously reported the presence of cytotoxic substances in extracts of the Danaid butterfly, Ideopsis similis. In the present study, we isolated cytotoxic substances against a human gastric cancer cell line, TMK-1, in I. similis pupae, with an activity similar to that of the adult butterfly. The basic fraction, prepared from a methanol extract, accounted for 83% of the cytotoxic activity. Two major cytotoxic substances were purified by HPLC, and one was determined to be a new phenanthroindolizidine alkaloid, trans-(+)-3,14alpha-dihydroxy-6,7-dimethoxyphenanthroindolizidine (1), and the other a known compound, trans-(+)-3,14alpha-dihydroxy-4,6,7-trimethoxyphenanthroindolizidine (2). The IC(50) values for TMK-1 cells were 0.5 ng/mL and 0.7 ng/mL, respectively. These two compounds showed similar cytotoxic potential with four other cancer cell lines including cervical, lung, and colon carcinomas and leukemia. Quantitative analyses indicated the presence of each of the two phenanthroindolizidine alkaloids at levels of 11-74 microg in each larva, pupa, or adult of I. similis. However, 1 was not detected in the leaves of Tylophora tanakae, a host plant for larvae of I. similis, and the level of 2 (2 microg per gram of leaves) was far less than that in the larvae. Since the leaves of T. tanakae are known to contain various phenanthroindolizidines, compounds 1 and 2 are presumably metabolically converted from such alkaloids in larvae of I. similis.

Alkaloids↗
PubMed2001

Nucleotide sequence, transcription map, and mutation analysis of the 13q14 chromosomal region deleted in B-cell chronic lymphocytic leukemia.

Deletions of the 13q14 chromosome region are associated with B-cell chronic lymphocytic leukemia (B-CLL) and several other types of cancer, suggesting the presence of a tumor suppressor gene. In previous studies the minimal region of deletion (MDR) was mapped to a less than 300-kilobase (kb) interval bordered by the markers 173a12-82 and 138G4/1.3R. For the identification of the putative tumor suppressor gene, the entire MDR (approximately 347 kb) has been sequenced, and transcribed regions have been identified by exon trapping, EST-based full-length complementary DNA cloning, database homology searches, and computer-assisted gene prediction analyses. The MDR contains 2 pseudogenes and 3 transcribed genes: CAR, encoding a putative RING-finger containing protein; 1B4/Leu2, generating noncoding transcripts; and EST70/Leu1, probably representing another noncoding gene (longest open reading frame of 78 codons). These genes have been sequenced in 20 B-CLL cases with 13q14 hemizygous deletion, and no mutations were found. Moreover, no somatic variants were found in the entire MDR analyzed for nucleotide substitutions by a combination of direct sequencing and fluorescence-assisted mismatch analysis in 5 B-CLL cases displaying 13q14-monoallelic deletion. The nondeleted allele of the CAR and EST70/Leu1 genes was expressed in B-CLL specimens, including those with monoallelic loss, whereas no expression of 1B4/Leu2 was detectable in B-CLL, regardless of the 13q14 status. These results indicate that allelic loss and mutation of a gene within the MDR is an unlikely pathogenetic mechanism for B-CLL. However, haplo-insufficiency of one of the identified genes may contribute to tumorigenesis. (Blood. 2001;97:2098-2104)

Animals↗
PubMed2001

Diffuse brain injury induces local expression of Na+/myo-inositol cotransporter in the rat brain.

We studied expression of an osmoprotective gene, sodium/myo-inositol cotransporter (SMIT) in Marmarou's animal model for human diffuse brain injury by in situ hybridization and immunohistochemistry. In rats with diffuse brain injury, transient upregulation of SMIT mRNA was exclusively observed in the lateral area of pyramidal tract in lower brainstem. The expression was induced at 1 h after injury, peaked at 24 h, and returned to almost control levels at 48 h. Upregulated expression was found mainly in small glia-like cells. By immunohistochemistry using antibodies to phosphorylated mitogen-activated protein (MAP) kinases, inductions of phosphorylated p44/42 MAP kinase were also observed after diffuse brain injury. Interestingly, the distribution patterns of induced phosphorylated p44/42 MAP kinase were completely coincident with those of upregulated SMIT mRNA after diffuse brain injury. These results suggest that diffuse brain injury induces local expression of SMIT by activation of p44/42 MAP kinase cascade. The confined SMIT induction may reflect regional differences of damage and/or cellular differences in sensitivity to neuropathological stresses caused by this injury.

Animals↗
PubMed2001

Improvement of splenomegaly and pancytopenia by enzyme replacement therapy against type 1 Gaucher disease: a report of sibling cases.

Gaucher disease is a genetic lipid storage disease and represents a potentially serious health problem. It arises from a deficiency of glucocerebrosidase activity with secondary accumulation of large quantities of glucocerebroside. Symptoms are usually multisystemic, often debilitating or disabling, and sometimes disfiguring, and they can lead to death. We report objective clinical response's to repeated infusion of human placental and recombinant glucocerebrosidase in 2 patients with type 1 Gaucher disease and increased hemoglobin levels and platelet counts. Splenic volume decreased during the period of enzyme administration. Enzyme replacement therapy has improved the treatment of type 1 Gaucher disease by safely and effectively arresting, decreasing, or normalizing many of its major signs and symptoms. Consideration by physicians must be given to Gaucher disease, and appropriate treatments must be given when confronted with cryptogenic pancytopenia or hepatosplenomegaly.

Adult↗
PubMed2001

Effects of the acyl chain composition of phosphatidylcholines on the stability of freeze-dried small liposomes in the presence of maltose.

The effects of the acyl chain composition of phosphatidylcholines (PCs) on the stability of small unilamellar vesicles during freeze-drying and rehydration in the presence of maltose were studied by monitoring the retention of a trapped marker, calcein, in the internal liposome compartment. In dipalmitoyl PC, beta-oleoyl-gamma-palmitoyl-PC and egg yolk PC liposomes, good or fair retentions (>50%) were observed in the presence of maltose, but maltose was ineffective in preserving retention in the dioleoyl PC (DOPC) liposomes (<10%). The extremely low retention in the DOPC liposome was ascribed to neither a formation of the inverted hexagonal phase of the liposomal membrane nor the fusion/aggregation of the liposomes in the drying-rehydration process. Differential scanning calorimetry measurements suggested that interactions of maltose with PC headgroups were essential to stabilizing the dry liposomes. These interactions were significant in the saturated or mixed chain liposomes but were markedly reduced in the DOPC liposomes.

Calorimetry, Differential Scanning↗
PubMed2001

Prognostic significance of thrombomodulin expression and vascular invasion in stage I squamous cell carcinoma of the lung.

Thrombomodulin (TM) is an important modulator of intravascular coagulation. TM exists on endothelial cells and on several types of tumor cells, especially squamous cell carcinoma cells. Tumor cell TM is thought to be associated with progression and metastasis of the tumor. To evaluate the prognostic significance of TM in lung cancer, we examined TM expression and vascular invasion in surgical specimens obtained from 90 patients with completely resected stage I non-small cell lung cancer (NSCLC). In addition, we correlate these pathologic data to other clinicopathologic data, including the outcome of the patients. Squamous cell carcinomas had a significantly higher incidence (P<0.0001) of TM expression (22/36 cases, 61%) than adenocarcinomas (9/54 cases, 17%). In 36 squamous cell carcinoma patients, both vascular invasion (P=0.0153; risk ratio 6.507) and TM non-expression (P=0.0282; risk ratio 3.584) were significant for a poor prognosis. Univariate analysis of patient survival rates also revealed that vascular invasion and TM expression were significant prognostic factors (P=0.0036 and 0.012, respectively). Further, combination analysis of vascular invasion and TM expression in the squamous cell carcinoma patients showed that the 5-year survival rate was 90% in patients with TM expression and without vascular invasion, but 21% in patients with vascular invasion and without TM expression (P=0.0004). Since our results suggest that vascular invasion and TM expression are independent prognostic factors of stage I squamous cell carcinoma of the lung, and since the two factors play different roles in the metastatic process of cancers (promotion of metastasis by vascular invasion and inhibition of metastasis by TM expression), the combination evaluation of vascular invasion and TM expression may be very significant in evaluating the prognosis of patients with completely resected stage I squamous cell carcinoma.

Adult↗
PubMed2001

The characterization of superoxide production of human neonatal neutrophil.

To assess the role of neutrophil in neonatal host defense against microbial infection, we characterized the superoxide anion (O(2-)) production of neonatal neutrophil on a biochemical basis. After taking an appropriate informed consent, neutrophils were obtained from cord blood immediately after transvaginal delivery and divided into two groups: the Preterm group, 15 neonates (27-36 weeks' gestation) and the Term group, 15 neonates (37-41 weeks' gestation). Eleven healthy adults served as controls in the Adult group. The value of N-formyl-methionyl-leucyl-phenylalanin (fMLP)-induced O(2-) production activity of neutrophils in the Preterm group using chemiluminescence assay was significantly lower than those values in both the Term and Adult groups (5.77+/-0.53x10(6) vs. 11.1+/-0.94x10(6) and 10.7+/-0.63x10(6) cpm; mean+/-S.E.M., p<0.05). In phorbol 12-myristate 13-acetate (PMA)-stimulation, the values of O(2-) production activity of neutrophils in both the Preterm and Term groups were significantly lower than that in the Adult group (13.0+/-1.66x10(6) and 18.0+/-1.44x10(6) vs. 27.3+/-1.45x10(6) cpm, p<0.05). Scatchard analysis of [(3)H]fMLP binding to neutrophil demonstrated a two-receptor model in each group, and the number of high-affinity receptors per neutrophil in the Preterm group was significantly lower than those in other groups (p<0.05). However, cord blood levels of proinflammatory cytokines, such as interleukin (IL)-6, -8, and tumor necrosis factor-alpha (TNF-alpha) did not differ in either neonatal group. These results indicated that the fMLP-induced O(2-)production activity of neutrophils in the term neonates was enhanced at the level of the receptor and suggested that this enhanced production contribute to the neonatal host defense against microbial infection.

Adult↗
PubMed2001

Cytotoxic effects of soluble factor in preeclamptic sera on human trophoblasts.

Evidence indicating abnormal biological behavior of trophoblasts has been seen in preeclamptic patients, but the mechanism is still unknown. We have previously shown that endothelial injury and neutrophil activation are induced by certain factors in preeclamptic sera. We investigated the effect of sera from eight preeclamptic and 11 normal pregnant women on cellular proliferation and viability of trophoblasts using 3H-thymidine incorporation and the trypan-blue dye exclusion test, respectively. Five of eight preeclamptic sera, but none of the normal pregnant sera, inhibited 3H-thymidine incorporation. The trypan-blue test revealed the sera reduced cellular viability. Gel permeation showed that the greatest growth-inhibitory activity corresponded to a molecular weight of 50 kDa. The serum-mixing test revealed this permeation and inhibitory preeclamptic sera suppressed the growth-promoting activity of normal pregnant sera in a dose-dependent manner. These results suggested the presence of certain factors in some preeclamptic sera that can affect cellular behavior of human trophoblasts.

Adult↗
PubMed2001

Effects of dopamine d2 receptor agonists in a pituitary transplantation-induced hyperprolactinaemia/anovulation model in rats.

1. In the present study, we investigated the effects of hyperprolactinaemia, induced by transplantation of anterior pituitary glands under the kidney capsule in female rats, on the relationship between serum and pituitary concentrations of the gonadotropins and on the oestrous cycle. 2. Rats with pituitary transplants showed increased serum prolactin concentrations and decreased serum concentrations of gonadotropins and increased pituitary concentrations of gonadotropins. Moreover, these rats showed persistent dioestrous and anovulation from 3 to 6 days after transplantation. 3. A single oral administration of cabergoline (at doses between 0.001 and 0.1 mg/kg) dose-dependently inhibited the elevated serum prolactin concentrations in hyperprolactinaemic rats. At 0.1 mg/kg, cabergoline induced a continuous reduction in serum prolactin concentrations for 5 days after administration. Terguride (0.1 mg/kg) and bromocriptine (10 mg/kg) also reduced serum prolactin concentrations at 1 and 3 days after administration. All three dopamine D2 receptor agonists increased serum gonadotropin concentrations and ovarian weight at 3 days after administration. 4. In rats exhibiting anovulation, a single oral administration of any one of the three dopamine D2 receptor agonists dose-dependently restored ovulation and a normal oestrous cycle appeared. Oral administration of cabergoline (0.03 mg/kg) or terguride (0.1 mg/kg) restored ovarian function and abolished the anovulation following a reduction in serum prolactin concentrations. However, bromocriptine (10 mg/kg) did not completely abolish anovulation. Following administration of terguride (0.3 mg/kg) or bromocriptine (30 mg/kg), only one normal oestrous cycle appeared; however, following cabergoline (0.1 mg/kg), two normal oestrous cycles appeared. 5. These results suggest that cabergoline has a potent and long-lasting action as a dopamine D2 receptor agonist and, thus, should be a useful drug for the treatment of galactorrhoea and hyperprolactinaemic amenorrhoea and/or anovulation in humans.

Animals↗
PubMed2001

Comparison of patient-controlled epidural analgesia with and without night-time infusion following gastrectomy.

To assess the analgesic efficacy and side effects of a supplemental night-time infusion in patient-controlled epidural analgesia (PCEA) after gastrectomy, we carried out a randomized, double-blind study. The number of requests were lower (P<0.005) in the PCEA plus night-time infusion group than in the PCEA alone group during the postoperative nights. Patients who had a PCEA plus night-time continuous infusion, slept with fewer interruptions than those who had only the PCEA. VAS pain scores on coughing were significantly lower (P<0.05) in the PCEA plus infusion group than in the PCEA alone group during the night following postoperative day 1. In conclusion, a night-time infusion in PCEA following gastrectomy decreases the incidence of postoperative pain, provides a better sleep pattern, and reduces the degree of the pain associated with coughing during the night.

Analgesia, Epidural↗
PubMed2001

Development of chemo-enzymatic process and manufacture of deoxynucleosides.

Manufacturing method for 2'-deoxynucleosides (dNus) has been developed using novel chemo-enzymatic process. The method consists of the chemical synthesis of 2'-deoxyribose 1-phosphate (dRP) and the enzymatic conversions of dRP into 2'-deoxyadenosine (dA), 2'-deoxyguanosine (dG) and 2'-deoxycytidine (dC). Large-scale preparation is successfully done, which demonstrates an applicability of this strategy to practical use. As thymidine is already under commercial-scale production, all four dNus are now ready for scale-up.

Cytosine↗
PubMed2001

Reversal effect of sulpiride on rotational behaviour of rats with unilateral frontal cortex ablation: an alternative explanation for the pharmacological mechanism of its antidepressant effect.

The antidepressant effect of sulpiride has been generally explained as the result of its preferential blocking effect on self-inhibitory presynaptic dopamine autoreceptors at low doses. Low dose haloperidol has the same blocking effect. In rats with unilateral ablation of the frontal cortex, methamphetamine administration induced mild contralateral rotation 10 days after the operation. We examined whether low dose sulpiride and haloperidol would have the same effect on this rotational model. High dose sulpiride (100 mg/kg) or low dose haloperidol (0.05 mg/kg) prevented this methamphetamine-induced rotation. However, low dose (15 mg/kg) sulpiride clearly reversed the direction of rotation. This reversal effect of low dose sulpiride is not explained by the preferential blocking effect on dopamine autoreceptors. The results suggest that low dose sulpiride, unlike low dose haloperidol, has a prominent blocking effect on D2 receptors in the frontal cortex. This unique effect of sulpiride may be relevant to its clinical antidepressant and anxiolytic effects at low doses.

Animals↗
PubMed2001

Clonality assay of hematopoietic disorders: significance of the buccal epithelium as non-hematopoietic control and of 95% rejection limit as a novel criterion for monoclonality.

In clonality assays using X chromosome inactivation patterns (XCIPs), several factors such as constitutive and acquired XCIP skewing, lack of appropriate controls for hematopoietic diseases including multilineage disorders, and ambiguous criteria for monoclonality, have complicated determination of clonality. To address these issues, we studied the significance of the buccal epithelium as a non-hematopoietic control and the usefulness of the 95% rejection limit as a criterion for monoclonality. Sixty-nine females informative for human androgen receptor gene (HUMARA) were divided into "young," "middle-aged" and "elderly" groups. When XCIP correlation between the buccal epithelium, peripheral granulocytes, and peripheral lymphocytes was analyzed, the buccal epithelium showed a good correlation with granulocytes and lymphocytes in "young" and "middle-aged" groups, whereas the correlation was poor for the "elderly" group. For all age groups, there was an excellent correlation between granulocytes and lymphocytes. When we performed clonality assay for seven "young" and "middle-aged" patients with various leukemic phases using buccal epithelium as a non-hematopoietic control, all cases were accurately evaluated with the aid of a novel criterion, the 95% rejection limit. Our findings suggest that the buccal epithelium may constitute an effective control, especially when a non-hematopoietic control is required, and that the 95% rejection limit may serve as a statistically-defined criterion for monoclonality.

Adult↗
PubMed2001

Neural representation of the luminance and brightness of a uniform surface in the macaque primary visual cortex.

The perceived brightness of a surface is determined not only by the luminance of the surface (local information), but also by the luminance of its surround (global information). To better understand the neural representation of surface brightness, we investigated the effects of local and global luminance on the activity of neurons in the primary visual cortex (V1) of awake macaque monkeys. Single- and multiple-unit recordings were made from V1 while the monkeys were performing a visual fixation task. The classical receptive field of each neuron was identified as a region responding to a spot stimulus. Neural responses were assessed using homogeneous surfaces at least three times as large as the receptive field as stimuli. We first examined the sensitivity of neurons to variation in local surface luminance, while the luminance of the surround was held constant. The activity of a large majority of surface-responsive neurons (106/115) varied monotonically with changes in surface luminance; in some the dynamic range was over 3 log units. This monotonic relation between surface luminance and neural activity was more evident later in the stimulus period than early on. The effect of the global luminance on neural activity was then assessed in 81 of the surface-responsive neurons by varying the luminance of the surround while holding the luminance of the surface constant. The activity of one group of neurons (25/81) was unaffected by the luminance of the surround; these neurons appear to encode the physical luminance of a surface covering the receptive field. The responses of the other neurons were affected by the luminance of the surround. The effects of the luminances of the surface and the surround on the activities of 26 of these neurons were in the same direction (either increased or decreased), while the effects on the remaining 25 neurons were in opposite directions. The activities of the latter group of neurons seemed to parallel the perceived brightness of the surface, whereas the former seemed to encode the level of illumination. There were differences across different types of neurons with regard to the layer distribution. These findings indicate that global luminance information significantly modulates the activity of surface-responsive V1 neurons and that not only physical luminance, but also perceived brightness, of a homogeneous surface is represented in V1.

Animals↗
PubMed2001

Effect of KAD-1229, a nonsulfonylurea hypoglycemic agent, on plasma glucose and insulin in streptozotocin-induced diabetic dogs.

Hypoglycemic agents with a rapid onset and short duration of action should be useful for controlling postprandial hyperglycemia. Our aim was to establish a diabetes mellitus model in dogs, and then during an oral glucose tolerance test to compare the hypoglycemic effect and insulinotropic action of KAD-1229, a new hypoglycemic agent, with that of gliclazide, a conventional sulfonylurea. In this model, KAD-1229 reduced the increase in plasma glucose level without producing hypoglycemia. Gliclazide had a weaker effect on reduction of the glucose increase and caused hypoglycemia via a significantly raised insulin secretion in the late phase. A rapid insulinotropic action of KAD-1229 was clearly observed in the portal venous blood. The results suggest that in type 2 diabetes caused by, at least, insulin deficiency, KAD-1229 may improve impaired insulin secretion in the early phase and attenuate hyperglycemia without causing a sustained hypoglycemia.

Animals↗
PubMed2001

Immunohistochemical detection of human gastrointestinal glutathione peroxidase in normal tissues and cultured cells with novel mouse monoclonal antibodies.

This is the first report to describe the successful detection of human gastrointestinal glutathione peroxidase in normal tissues by Western blotting and immunohistochemical staining techniques. Four hybridoma clones producing monoclonal antibodies (MAbs) against the human gastrointestinal glutathione peroxidase were established from mice immunized with a gastrointestinal glutathione peroxidase-derived peptide. The MAbs did not crossreact with other members of the glutathione peroxidase family, be it cellular glutathione peroxidase, phospholipid hydroperoxide glutathione peroxidase, or extracellular glutathione peroxidase. Although the MAbs were found to react with a 24-kD protein in a Western blotting assay using gastric carcinoma cell extracts as antigen, they did not react with a B-lymphoblastoid cell extract. Immunohistochemical staining showed gastrointestinal glutathione peroxidase localized in the cytoplasm and in the nucleus of gastric carcinoma cells. Moreover, gastrointestinal glutathione peroxidase was detected in tissue extracts of human stomach, small intestine, large intestine, liver, and gallbladder by Western blotting, and its localization was immunohistochemically confirmed in the mucosal epithelia of the basal area of gastric pits and intestinal crypts.

Aged↗