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Biomedical subjects

T Kitajima

Publications and source records attributed to T Kitajima.

At least 55 records · Page 3Linked to original sources
PubMed2000

Linkage of persistent cholangitis after bilioenterostomy with biliary carcinogenesis in hamsters.

Biliary carcinoma occurring after bilioenterostomy has been reported as a late complication of this surgical procedure. The present study was designed to determine if bilioenterostomy promotes biliary carcinogenesis, and also to clarify the relationship between biliary inflammation and biliary carcinogenesis in hamsters. Syrian hamsters underwent a simple laparotomy (SL), choledochoduodenostomy (CD) or choledochojejunostomy (CJ). All hamsters received subcutaneous injections of the chemical carcinogen, N-nitrosobis (2-oxopropyl) amine (BOP), and were sacrificed 20 weeks after surgery. Neoplastic lesions in the biliary tree were histologically examined, and the presence and degree of cholangitis was also evaluated with special reference to biliary carcinogenesis. The incidence of bile duct carcinoma was not significantly different among the three groups. Numerous bile duct carcinomas, however, were recognized in the bilioenterostomized animals, especially in the CJ group. Moreover, significant correlations between biliary carcinogenesis and the presence of cholangitis were noted in both the CD and CJ groups, but not in the SL control group. Severe cholangitis was evident in the CJ group, and the number of biliary carcinomas was well correlated with the degree of cholangitis. In conclusion, the risk of carcinoma in the biliary tract may increase when persistent cholangitis is present after biliary reconstruction.

Animals↗
PubMed1999

Thalidomide increases both REM and stage 3-4 sleep in human adults: a preliminary study.

Polysomnography was used to assess the effect of thalidomide on human sleep. This compound significantly increased the time spent in REM and stage 3-4 sleep as compared with placebo. On the other hand, thalidomide significantly decreased the time spent in stage 1, while the time spent in stage 2 was unchanged. The effect of thalidomide on REM and stage 3-4 sleep is unique as compared with other hypnotics. Although the mode of action of this compound is unknown, further studies on thalidomide should help in our understanding of the mechanisms of sleep regulation.

Adult↗
PubMed1999

Propofol prevents delayed neuronal death following transient forebrain ischemia in gerbils.

PURPOSE: This study was conducted to ascertain whether propofol may protect against delayed neuronal death in the hippocampal CA1 subfield in gerbils. METHODS: Thirty-five gerbils were randomly assigned to five groups: Group I, the control group, a sham operation treated with physiological saline solution (PSS); Group II, ischemia/reperfusion treated with PSS; Group III, ischemia/reperfusion treated with 50 mg x kg(-1) propofol; Group IV, ischemia/reperfusion treated with 100 mg x kg(-1) propofol; Group V ischemia/reperfusion treated with 150 mg x kg(-1) propofol. Transient forebrain ischemia was induced by occluding the bilateral common carotid arteries for four minutes under N2O/O2/halothane anesthesia after administration of propofol or PSS. Five days later, histopathological changes in the hippocampal CA1 subfield were examined using a light microscope and degenerative ratio of the pyramidal cells were measured according to the following formula: (number of degenerative pyramidal cell/total number of pyramidal cells per 1 mm of hippocampal CA1 subfield) x 100. RESULTS: In group II, the pyramidal cells were atrophic and pycnotic; vacuolation and structural disruption of the radial striated zone was observed. In the other four groups, these changes were not observed. The degenerative ratios of pyramidal cells were as follows; group I: 5.9 +/- 1.9%, group II: 94.6 +/- 2.5% (P < 0.01), group III: 10.7 +/- 1.7%, group IV: 9.7 +/- 1.8%, group V: 9.2 +/- 1.9%. CONCLUSION: This study suggests that propofol may prevent delayed neuronal death in the hippocampal CA1 subfield after cerebral ischemia/reperfusion in gerbils.

Analysis of Variance↗
PubMed1999

B-cell activation in the mesenteric lymph nodes of resistant BALB/c mice infected with the murine nematode parasite Trichuris muris.

Immune responses in resistant BALB/c mice infected with the murine nematode parasite Trichuris muris were examined. Following the establishment of infection, worm burdens of T. muris were expelled by BALB/c mice by day 21 postinfection (p.i.). Specific immunoglobulin G1 (IgG1) antibodies to T. muris excretory/secretory (E/S) antigens were detected in sera from infected mice, though specific IgG2a antibodies were not observed during infection. Ig-producing cells increased in the mesenteric lymph nodes (MLN) of infected mice on days 7, 14, and 21 p.i., with the greatest increase in numbers of IgG- and IgA-producing cells occurring on day 14. Marked increases in the relative percentages of B220+ and surface Ig+ (sIg+) cells were observed in the MLN of infected mice on days 14 and 21 p.i. Furthermore, cellular expansion of the MLN in infected mice resulted in an increase in the absolute numbers of B220+ and sIg+ cells. The levels of interleukin 2 (IL-2), IL-4, and interferon-gamma (IFN-gamma) detected in the supernatants from concanavalin A-stimulated MLN cells of infected mice were higher than those found in normal mice. Consequently, the expulsion of T. muris in resistant BALB/c mice was concomitant with cytokine production and B-cell activation in the MLN of infected mice. These results suggest the involvement of B-cell responses in protective immunity to T. muris infection.

Animals↗
PubMed1999

HpEts, an ets-related transcription factor implicated in primary mesenchyme cell differentiation in the sea urchin embryo.

The mechanism of micromere specification is one of the central issues in sea urchin development. In this study we have identified a sea urchin homologue of ets 1 + 2. HpEts, which is maternally expressed ubiquitously during the cleavage stage and which expression becomes restricted to the skeletogenic primary mesenchyme cells (PMC) after the hatching blastula stage. The overexpression of HpEts by mRNA injection into fertilized eggs alters the cell fate of non-PMC to migratory PMC. HpEts induces the expression of a PMC-specific spicule matrix protein, SM50, but suppresses of aboral ectoderm-specific arylsulfatase and endoderm-specific HpEndo16. The overexpression of dominant negative delta HpEts which lacks the N terminal domain, in contrast, specifically represses SM50 expression and development of the spicule. In the upstream region of the SM50 gene there exists an ets binding site that functions as a positive cis-regulatory element. The results suggest that HpEts plays a key role in the differentiation of PMCs in sea urchin embryogenesis.

Amino Acid Sequence↗
PubMed1999

Hbox1 and Hbox7 are involved in pattern formation in sea urchin embryos.

In spite of their potential importance in evolution, there is little information about Hox genes in animal groups that are related to ancestors of deuterostome. It has been reported that only two Hox genes (Hbox1 and Hbox7) are expressed significantly in sea urchin embryos. Expression of Hbox1 protein is restricted to the aboral ectoderm, and Hbox7 expression is restricted to oral ectoderm, endoderm and secondary mesenchyme cells in sea urchin embryos after the gastrula stage. With the aim of gaining insight into the role of Hbox1 and Hbox7 in sea urchin development, Hbox1 and Hbox7 overexpression experiments were performed. Overexpression of Hbox1 repressed the development of oral ectoderm, endoderm and mesenchyme cells. On the contrary, overexpression of Hbox7 repressed the development of aboral ectoderm and primary mesenchyme cells. The data suggest that Hbox1 and Hbox7 are expressed in distinct non-overlapping territories, and overexpression of either one inhibits territory-specific gene expression in the domain of the other. It is proposed that an important function of both Hbox1 and Hbox7 genes is to maintain specific territorial gene expression by each one, in its domain of expression, while repressing the expression of the other in this same domain.

Amino Acid Sequence↗
PubMed1999

Enhancement of secretion of human procollagen I in mouse HSP47-expressing insect cells.

We previously demonstrated that insect cells were able to synthesize recombinant human procollagen I as triple-helical heterotrimers when transfected with cDNAs of both proalpha1(I) and proalpha2(I) chains. However, most of the heterotrimers were retained within the cells, unlike in the case of mammalian cells [Tomita, M., Kitajima, T., and Yoshizato, K. (1997) J. Biochem. 1061-1069]. In an attempt to improve the secretion of the heterotrimers, we introduced the putative collagen-specific chaperone HSP47 into this insect expression model. Mouse HSP47 produced by the insect cells bound intracellularly to both human proalpha1(I) and proalpha2(I) chains and enhanced the secretion of procollagen I heterotrimers. HSP47 was also coexpressed with either proalpha1(I) chains or proalpha2(I) chains, which showed that it enhanced the secretion of the former but not the latter. This selective effect of HSP47 was similarly observed in the cells treated with inhibitors of procollagen triple helix formation, indicating that HSP47 can also accelerate the secretion of non-helical procollagens. HSP47 did not change the intracellular solubility of proalpha1(I) and proalpha2(I) chains in 1% NP-40, eliminating the possibility that it prevents proalpha chains from aggregating into insoluble forms within the insect cells. We concluded that HSP47 can play a role in the secretion of alpha1(I)-procollagen chains in the insect cell model. The present study also demonstrated the dissimilarity in the mechanism of folding and secretion of the expressed procollagen I between the insect and mammalian cells.

Animals↗
PubMed1999

The effects of combined sympathetic block and intravascular infusion of prostaglandin E1 on brachial arterial blood flow in dogs.

UNLABELLED: We compared the effects of stellate ganglion block (SGB) with those of SGB combined with an intravascular infusion of prostaglandin E1 (PGE1) on brachial arterial blood flow (BABF) in 24 mongrel dogs. The experimental protocol was designed so that the dogs received one of the following: SGB with 0.5% mepivacaine 1.0 mL (n = 8); combined SGB and IV infusion of PGE1 at a rate of 150 ng x kg(-1) x min(-1) for 10 min (n = 8); or combined SGB and intraarterial (IA) infusion of PGE1 at a rate of 0.1 ng x kg(-1) x min(-1) for 10 min (n = 8). BABF increased significantly in all groups and reached a maximum of 67% 10 min after SGB, 124% with the combined SGB and IV infusion of PGE1, and 117% with the combined SGB and IA infusion of PGE1. We conclude that combined SGB and IV or IA infusion of PGE1 increases BABF significantly compared with SGB alone. IMPLICATIONS: Combined stellate ganglion block and intraarterial or IV infusion of prostaglandin E1 increases brachial arterial blood flow significantly compared with stellate ganglion block alone.

Alprostadil↗
PubMed1999

Willingness to pay for long-term care insurance system in a municipality in Tokyo.

This study attempted to estimate the valuation of Long-term care (LTC) insurance system among the residents in a municipality in Tokyo by applying the Willingness to Pay (WTP) approach. The mean WTP for Group one (those aged 65 and over) and Group two (those aged between 40 and 64) was estimated to be 13,305 Japanese Yen and 8,722 Japanese Yen, respectively. Both amounts exceed the contribution estimated by the Ministry of Health and Welfare (2,500 Japanese Yen). The result reflects a high expectation for the system especially among those in Group one. It also suggests that those in Group one may be able to shoulder more financial responsibility for the system. Further research on WTP for LTC insurance system is deemed beneficial for its successful management.

Adult↗
PubMed1999

[Influence of nitric oxide on cerebral hemodynamics during endotoxemia in dogs].

The aim of this study is to clarify the influence of nitric oxide (NO) in cerebral circulation during endotoxemia. Two groups of 24 mongrel dogs (N = 12 each) received saline 1 ml.kg-1.h-1 or endotoxin (lipopolysaccharide, LPS) 500 ng.kg-1.h-1 for 3 hours. To determine changes of NO in the systemic and cerebral circulation, we measured NOx (NO2-/NO3-) in the femoral artery and superior sagittal sinus as metabolites of NO using the Griess method. We also measured the concentrations of cerebral oxyhemoglobin (HbO2), deoxyhemoglobin (Hb), total hemoglobin (total Hb) and cytochrome aa3 (Cytaa3) using near-infrared laser spectroscopy. Changes in cerebral blood volume were evaluated from the total Hb. NOx in systemic and cerebral circulation increased significantly after infusion of LPS. Therefore, the increased production of NO in cerebral circulation was consistent with increase of cerebral blood volume. In conclusion, it seems reasonable to assume that increased cerebral blood volume may result from increased production of cerebral NO during endotoxemia.

Animals↗
PubMed1999

[Two cases of an intracranial large hemangiopericytoma associated with brain swelling in the early operative stage].

Intracranial hemangiopericytomas are hypervascular tumors. Consequently, resection of these tumors must occasionally be stopped owing to profuse bleeding. We report two cases of large intracranial hemangiopericytoma whose resection had to be stopped owing not to bleeding but to brain swelling. These patients were treated with large doses of barbiturate until the intracranial pressure had normalized. After preoperative irradiation therapy, the residual tumors were easily removed without serious complications. We speculate that the brain tissue around a large hemangiopericytoma might be under ischemia because of long-standing compression and deviation of blood to the hypervascular tumor. A large amount of blood flowing into these brain tissues due to external and internal decompression inverts cerebral perfusion acutely from ischemia to hyperemia. The brain swelling in the early operative stage would be evoked by this "inverted cerebral hyperemia". We found that brain swelling is sometimes encountered during the resection of a large hemangiopericytoma even in the early operative stage. If swelling occurs, tumor resection should be stopped immediately and intracranial pressure should be controlled. The residual tumor can then be easily removed without complications after preoperative irradiation therapy.

Adult↗
PubMed1999

[A case of cardiac arrest after torsades de pointes due to prolonged QT interval syndrome possibly associated with subarachnoid hemorrhage].

An 58-year-old woman with prolonged QT interval syndrome possibly associated with subarachnoid hemorrhage underwent clipping for cerebral artery aneurysm. Anesthesia was induced with diazepam, fentanyl and vecuronium, and maintained with nitrous oxide (66%)-oxygen and sevoflurane (1%) with fentanyl. However, three hours after the start of operation, torsades de pointes suddenly appeared and cardiac arrest was followed. After cardiopulmonary resuscitation, sinus rhythm was restored. At that time, serum potassium was decreased to 2.7 mEq.l-1. Five days after the operation, she died despite cardiopulmonary resuscitation for frequent episodes of ventricular tachycardia including torsades de pointes. Ventricular tachycardia including torsades de pointes may have been caused by decreased serum potassium.

Anesthesia, General↗
PubMed1999

[Evaluation of child-rearing environmental factors that affect the occurrence of sudden infant death syndrome: interview conducted by public health nurses].

PURPOSE: We examined the child-rearing environmental factors that affect the occurrence of sudden infant death syndrome (SIDS) by using a nation-wide survey. METHOD: Infants who died due to SIDS between January 1996 and June 1997 in Japan were identified from death certificates. Controls of the same sex, birthplace, and birth months as the corresponding SIDS were chosen from birth certificates. Interviews of both cases and controls were undergone in January and February 1998 by public health nurses. RESULTS: The following Child-rearing factors exhibited a significant relationship with the occurrence of SIDS: 1. Concerning the sleeping position, the prone position was associated with increased risk compared to the supine position, with an odds ratio of 3.02 (95% c.i. 2.07-4.65). 2. Regarding the feeding method, artificial feeding only demonstrated a higher risk than breast feeding only, with an odds ratio of 4.92 (95% c.i. 2.78-9.63). 3. With regard to smoking, infants with both parents who smoked exhibited a higher risk than infants where neither parents smoked, with an odds ratio of 3.50 (95% c.i. 1.74-8.32).

Child Rearing↗
PubMed1999

[Anesthetic management of a patient with postthymectomy myasthenia gravis].

A 56-year-old male who had received total thymectomy for treatment of myasthenia gravis was scheduled for sigmoidectomy under general anesthesia. Since his symptoms had become worse after the thymectomy along with increased anti-acetylcholine receptor antibody titer, preoperatively we could not estimate his sensitivity to non-depolarizing muscle relaxants. We initially tried tracheal intubation without using a non-depolarizing muscle relaxant immediately after intravenous injection of propofol 2 mg.kg-1 and fentanyl 4 micrograms.kg-1. Since the intubation was unsuccessful, however, vecuronium 0.01 mg.kg-1 was repeatedly administered until TOF ratio reached 0%. Successful intubation was performed with 3.5 mg of vecuronium. We conclude that the initial trial of tracheal intubation should be performed without a non-depolarizing muscle relaxant in patients with myasthenia gravis whose symptoms have become worse after thymectomy. If first attempt is unsuccessful, the tracheal intubation should be performed with a smaller dose of vecuronium using an electrical nerve stimulator.

Anesthesia, Epidural↗
PubMed1999

[Differential lung ventilation using Fogarty catheter after accidental damage of bronchial blocker cuff].

We performed differential lung ventilation using a Fogarty catheter after accidental damage of a bronchial blocker. A 57-year-old-man underwent thoracoscopic surgery for right pneumothorax. Anesthesia was induced with fentanyl and midazolam, and maintained with propofol and continuous epidural block with 2% mepivacaine. We used a single lumen endotrachial tube with a bronchial blocker for differential lung ventilation. We inserted the tip of the bronchial blocker into the right bronchus under fiberoptic broncoscopy after the patient had been placed in the lateral position. Four milliliters of air were injected into the bronchial blocker cuff before inserting the thoracoscope and differential lung ventilation was started. The right lung expanded suddenly because of accidental damage of the cuff one hour after starting surgery. We inserted a Fogarty catheter (10 Fr.) into the right bronchus under fiberoptic broncoscopy. Its balloon was inflated for differential lung ventilation. The procedure was performed successfully and uneventfully. We conclude that Fogarty catheter is an effective replacement for a damaged bronchial blocker cuff during differential lung ventilation.

Catheterization↗