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Biomedical subjects

M Hozumi

Publications and source records attributed to M Hozumi.

At least 19 recordsLinked to original sources
PubMed2003

Easy and accurate targeting of deep-seated hepatic tumors under laparoscopy with a forward-viewing convex-array transducer.

BACKGROUND: It is technically difficult to puncture deep-seated hepatic tumors by conventional laparoscopic ultrasonography with a linear-array probe. We have developed a laparoscopic ultrasonography system with a convex-array probe. METHODS: The laparoscopic system used had a fixed forward-viewing convex-array transducer, and a guide groove for puncture was added to the back of the unit. These characteristics enabled us to continuously monitor the position of the needle tip on the ultrasonographic image immediately after puncturing on the liver surface. We attempted tumor puncture in 11 patients with hepatocellular carcinoma under a new probe guidance. RESULTS: The mean puncturing distance up to the tumors was 38.7 mm. All punctures were successful on the first pass and the tumors were treated with radiofrequency ablation. CONCLUSION: Using this new equipment, puncturing hepatic tumors for treatment is relatively easy, irrespective of the position of the tumor.

Adult↗
PubMed2001

Laparoscopic adhesiolysis for recurrent small bowel obstruction: long-term follow-up.

BACKGROUND: Recurrent small bowel obstruction caused by postoperative adhesions has traditionally been treated by conventional laparotomy, but laparoscopic management of acute small bowel obstruction has been reported. The aim of this study was to assess the long-term efficacy and clinical outcome of laparoscopic adhesiolysis for recurrent small bowel obstruction. METHODS: After conservative treatment, elective laparoscopic treatment was attempted in 17 patients hospitalized for recurrent small bowel obstruction after abdominal or pelvic surgery. RESULTS: Postoperative adhesions were identified laparoscopically in all patients. Laparoscopic treatment was possible in 14 patients (82.4%). Conversion to laparotomy was required for 3 patients (17.6%) because of intestinal perforation (n = 1) or a convoluted mass of adherent bowel (n = 2). Long-term follow-up was possible in 16 patients. Two recurrences of small bowel obstructions were noted over a mean follow-up period of 61.7 months. CONCLUSIONS: Laparoscopic adhesiolysis is a safe and effective treatment for recurrent small bowel obstruction. Conversion to laparotomy should be considered in patients with dense adhesions.

Feasibility Studies↗
PubMed2001

Central serotonergic mechanisms on head twitch response induced by benzodiazepine receptor agonists.

Intraperitoneal injection of benzodiazepine receptor agonists (estazolam, zopiclone, triazolam: 0.03-0.24 mmol/kg) induces the head twitch response (HTR). The present study was undertaken to examine the possible participation of the serotonergic system in the mechanism of head twitches induced by benzodiazepine receptor agonists (BZ-RAs). The HTR induced by BZ-RAs was suppressed by pretreatment with ketanserine (1 mg/kg, i.p.), a selective 5-HT(2) receptor antagonist. Pretreatment with fluoxetine (10 mg/kg, i.p.), a 5-HT reuptake inhibitor, and 8-hydroxy-2-(di-n-propylamino)tetralin, a 5-HT(1A) receptor agonist, also suppressed the HTR induced by BZ-RAs. These results suggest that the HTR induced by BZ-RAs may be the result of an activation of postsynaptic 5-HT(2) receptors, probably due to direct action.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1999

The role of laparoscopic US and laparoscopic US-guided aspiration biopsy in the diagnosis of multicentric hepatocellular carcinoma.

BACKGROUND: Detection of small hepatocellular carcinomas has become possible with improvements in various diagnostic imaging techniques. However, intraoperative US can detect lesions not visualized by any preoperative imaging study in which case it is difficult to determine whether the lesion is a hepatocellular carcinoma. METHODS: Nodular lesions detected by laparoscopic US in 186 patients with hepatocellular carcinoma were examined and we evaluated the diagnostic ability of laparoscopic US to detect multicentric hepatocellular carcinoma. RESULTS: One hundred thirty-four new nodular lesions were detected by laparoscopic US in 64 (34.4%) of 186 patients. Aspiration biopsy under laparoscopic US guidance was performed on the 134 nodules, and 28 nodules in 23 (12.4%) of the 186 patients were histologically diagnosed as hepatocellular carcinoma. Of these 23 patients, 18 had been diagnosed with solitary hepatocellular carcinoma before laparoscopic US. One hundred six of the newly detected lesions were initially diagnosed as noncarcinomatous nodules, but the diagnosis of 10 of these lesions was changed to hepatocellular carcinoma during follow-up that was as long as 96 months. CONCLUSIONS: Laparoscopic US is useful in the initial diagnosis of hepatocellular carcinoma and impacts treatment selection by more accurately defining the presence of multicentric hepatocellular carcinomas.

Biopsy, Needle↗
PubMed1999

Prognosis of small hepatocellular carcinoma after laparoscopic ethanol injection.

BACKGROUND: Most patients with hepatocellular carcinoma have underlying cirrhosis, and this impairment of liver function makes hepatectomy difficult, prompting the use of other modalities such as transcatheter arterial embolization and percutaneous ethanol injection. METHODS: Laparoscopic ethanol injection was performed in 48 previously untreated patients with hepatocellular carcinoma smaller than 2 cm in diameter. Long-term survival was evaluated. RESULTS: In 12 patients, hepatocellular carcinoma was not detected by trans-cutaneous ultrasonography but could be demonstrated by laparoscopic ultrasonography. Laparoscopic ethanol injection did not cause serious complications in any patient. The mean hospital stay after ethanol injection was 8.6 days (4 to 15 days). The cumulative survival rate was 86.7% at 3 years and 60.0% at 5 years. According to the Child-Pugh classification, the cumulative survival rate at 5 years was 87.9% for class A, 65.7% for class B, and 28.6% for class C. CONCLUSIONS: The long-term prognosis for patients with small hepatocellular carcinoma treated solely by laparoscopic ethanol injection is satisfactory but still dependent on underlying liver function.

Adult↗
PubMed1998

Differentiation therapy of leukemia: achievements, limitations and future prospects.

Differentiation therapy in patients with acute promyelocytic leukemia (APL) using all-trans-retinoic acid (ATRA) has now been established as an effective strategy for the treatment of leukemia. However, the clinical response of patients with leukemias other than APL to differentiation inducers is limited, often with inconsistent outcome. Recently, numerous new differentiation inducers for various leukemia cells have been developed, some of which have had therapeutic effects on various leukemias in preclinical and clinical trials. Additionally, molecular control mechanisms of differentiation, and apoptosis of various leukemia cells by differentiation inducers have been studied extensively. These studies suggest that problems underlying the current discrepancy between preclinical and clinical therapeutic efficacy of leukemias can be overcome by these basic studies together with multidisciplinary studies on the therapy of leukemias in combination with differentiation therapy and other conventional therapies.

Animals↗
PubMed1998

Antioxidant vitamin levels in plasma and low density lipoprotein of obese girls.

To investigate the antioxidant status of obese children, we analyzed beta-carotene and alpha-tocopherol levels in plasma and low density lipoprotein (LDL). We also analyzed the fatty acid composition of LDL as a substrate for oxidative stress. The plasma beta-carotene and alpha-tocopherol levels were relatively lower in obese girls than in normal controls. However, the plasma alpha-tocopherol/lipids ratio was significantly lower in obese girls than in normal controls. Both LDL beta-carotene and LDL alpha-tocopherol levels were significantly lower in obese girls than in normal controls, although no obvious differences were observed in plasma levels. In obese girls LDL contained more polyunsaturated fatty acid (PUFA) compared with normal controls. When the peroxidizability index (PI) was calculated to estimate the susceptibility of lipids to oxidative stress, obese girls had significantly higher PI values than normal controls. Both the LDL beta-carotene/PI ratio and the LDL alpha-tocopherol/PI ratio were significantly lower in obese girls than in normal controls. These results indicate the increased susceptibility of LDL to oxidative stress in obese girls which may promote atherosclerosis later in life.

Adolescent↗
PubMed1998

Plasma beta-carotene, retinol, and alpha-tocopherol levels in relation to glycemic control of children with insulin-dependent diabetes mellitus.

Plasma beta-carotene, alpha-tocopherol and retinol were measured in 15 female and 5 male children with insulin-dependent diabetes mellitus (IDDM), and the correlations with plasma hemoglobin A1c (HbA1c) and fructosamine were analyzed. Twelve female and 8 male children served as age-matched controls. The plasma beta-carotene and alpha-tocopherol levels of the IDDM children were significantly higher than those of the control children, but there were no differences in plasma retinol or total lipid levels. The plasma beta-carotene level, beta-carotene/retinol ratio and beta-carotene/total lipids ratio each showed significant correlations with serum HbA1c and fructosamine in all subjects studied. Similarly, the plasma alpha-tocopherol level and alpha-tocopherol/total lipids ratio were correlated with these indexes of glycemic control. These findings suggest certain mechanisms may exist to prevent lipid peroxidation and vascular complications in IDDM patients.

Adolescent↗
PubMed1997

[Relationship between learning behavior and genetic factor on immobility shown during forced swimming test].

The relationship between learning and genetic factor on immobility in mice during a forced swimming test (FST) has been studied. The duration of immobility during the FST did not change significantly after the administration of either scopolamine (2.5 mg/kg, ip) or cyclohexamine (150 mg/kg, ip), although both drugs produced impairment in the learning task. This suggests that the increase in immobility observed during the second trial of the FST may not be related to learning which could occur during the first trial. Concerning the strain difference, first, the duration of immobility in C3H mice was shorter than that in ICR, ddY, C57BL and BALB mice. Second, after receiving shock stress in a box, ICR, ddY and C57BL mice, but not C3H mice showed a marked decrease in locomotor activity when placed in the box again without shock. Also during the FST, both C57BL and ddY mice, but not C3H mice showed prolongation of immobility and reduction in swimming after shock stress. The changes in locomotor activity, and immobility and swimming during the FST caused by shock stress in ddY mice recovered to normal levels after treatment with imipramine. From these results, it is suggested that the immobility shown during the FST, which may be independent of learning and dependent on some genetic factor, is a suitable model of depression in animals.

Animals↗
PubMed1997

Involvement of dopaminergic neurons in mouse-killing aggression in rats.

The sites associated with dopamine neurons which produce mouse-killing aggression (muricide) were examined in the rat brain. Muricide appeared in 60-80% of rats after being fed a thiamine-deficient diet for 28 days. Microinjection of dopamine (500 ng/rat) into the olfactory bulb (OB) significantly suppressed muricide, whereas injection into other brain areas failed to do so. The incidence of muricide after dopamine injection was 40% at 5 min and 20% at 15-30 min. When 6-hydroxydopamine (8 micrograms/0.5 microliter), following pretreatment with desmethylimipramine (25 mg/kg i.p.), was injected twice into the ventral tegmental area (VTA) or the olfactory bulb (OB) in nonkiller rats during thiamine-deficient feeding, the occurrence of muricide gradually increased over time. The present results suggest that degeneration of dopamine neurons projecting from the VTA to the OB may be related to mouse-killing aggression in rats.

Aggression↗
PubMed1996

Detection of in vivo differentiation of murine WEHI-3B D+ leukemia cells transfected with the lac-Z marker gene using two-color flow cytometry.

The in vivo induction of the differentiation of murine WEHI-3B D+ myelomonocytic leukemia cells was measured by flow cytometry, simultaneously staining leukemia cells for the marker exogenous beta-galactosidase and for differentiation by the antigen Mac-1 (CD11b/CD18). The WEHI-3B D+ leukemia cells were transfected with the E. coli lac-Z gene by electroporation and subclones that constitutively expressed high levels of the lac-Z gene product beta-galactosidase were established. Flow cytometric analyses of cells in the peritoneal cavities of mice bearing leukemia cells showed that cells continued to express beta-galactosidase for at least 14 days, and they were distinguishable from host-derived cells in vivo by their expression of the transfected gene. Simultaneous determination of the beta-galactosidase activity and Mac-1 content of cells in the peritoneal cavities of mice revealed that administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF) to the mice enhanced the expression of Mac-1 antigen by beta-galactosidase-positive cells. The results demonstrate that G-CSF may have clinical potential as a therapeutic differentiating agent, and that flow cytometric analysis provides a useful in vivo system to evaluate the therapeutic potential of agents capable of inducing terminal differentiation.

Animals↗
PubMed1996

Induction of differentiation and enhancement of vincristine sensitivity of human erythroleukemia HEL cells by vesnarinone, a positive inotropic agent.

We examined the effect of vesnarinone, an oral cardiotonic, on the growth and differentiation of human myeloid leukemia cells. Vesnarinone alone markedly induced erythroid differentiation of HEL cells. All-trans-retinoic acid also induced erythroid differentiation of the cells, and the differentiation was greatly enhanced by combined treatment with vesnarinone and retinoic acid. HEL cells are highly resistant to some anticancer drugs, including vincristine, but treatment with vesnarinone greatly increased the sensitivity of HEL cells to vincristine. Enhancement of vincristine sensitivity by vesnarinone was not as significant for other leukemia cells. Expression of P-glycoprotein in HEL cells was effectively inhibited by vesnarinone, suggesting that the restoration of vincristine sensitivity is associated with decrease of P-glycoprotein expression in HEL cells. The plasma level of vesnarinone required to induce differentiation of leukemia cells is 30 micrograms/mL, which could be achieved with oral administration. These results suggest that vesnarinone should be useful in differentiation therapy for some types of myelogenous leukemia.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

A new function of Nm23/NDP kinase as a differentiation inhibitory factor, which does not require it's kinase activity.

We recently identified a differentiation inhibiting factor (I-factor) in mouse myeloid leukemia M1 cells as a murine homolog of nm23-H2/nucleoside diphosphate kinase (NDPK)-B gene product. We examined the I-factor activities of several authentic nm23/NDPK proteins, i.e. recombinant rat NDPK alpha and beta, recombinant mouse nm23-M1 and -M2, and recombinant human nm23-H1 and -H2 containing a mutant nm23-H2His protein lacing NDPK activity. Almost all these nm23/NDPK proteins showed I-factor activity. Moreover, to understand the active domain exhibiting I-factor activity of nm23-H2 protein lacking NDPK activity, we have investigated the I-factor activities of some truncated nm23-H2 proteins. The truncated nm23-H2 protein containing N-terminal peptide 1-60 retained the I-factor activity. These results provide the first evidence for a function of nm23/NDPK as a differentiation inhibiting factor in leukemic cells, that is independent of its NDPK activity and dependent on the presence of N-terminal peptide.

Animals↗
PubMed1995

alpha-Methylated tryptamine derivatives induce a 5-HT receptor-mediated head-twitch response in mice.

The two alpha-methylated tryptamine derivatives, 5- (5-FMT) and 6-fluoro-alpha-methyltryptamine (6-FMT), rapidly induced a head-twitch response (HTR) in mice. Two derivatives that lack the methyl group in their chemical structures, 5- (5-FT) and 6-fluorotryptamine (6-FT), did not induce the HTR. The induced HTR was depressed by pretreatment with cycloheptadine, p-chlorophenylalanine or fluoxetine, but was potentiated by 5,7-dihydroxytryptamine. Both 5- and 6-FMT increased brain 5-HT levels in hypothalamus, hippocampus, brainstem, striatum and cortex. 5-FMT decreased the levels of 5-hydroxyindoleacetic acid in those regions, but 6-FMT caused a significant decrease in only the hypothalamus and cortex. The two methylated derivatives inhibited mouse brain MAO-A activity more selectively than non-methylated derivatives. The results suggest that the HTR induced by 5- and 6-FMT may result from increased activity of central 5-HT neurons, probably due to increased 5-HT levels after MAO-A inhibition. This probably results in release of 5-HT with a concomitant increased interaction with postsynaptic 5-HT2 receptors. The present results also indicate the importance of the methyl group to selective MAO-A inhibition by the substrate-analogues tested, and the concomitantly induced animal behavior.

Animals↗