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Biomedical subjects

Y Yoshikawa

Publications and source records attributed to Y Yoshikawa.

At least 163 records · Page 9Linked to original sources
PubMed1997

Unsuspected gallbladder cancer diagnosed by laparoscopic cholecystectomy: a clinicopathological study.

Laparoscopic cholecystectomy (LC) for gallstones has become a popular treatment modality, but LC for gallbladder cancer is not yet established and its prognosis is still unknown. We clinicopathologically studied unsuspected gallbladder cancer presenting at pathologic evaluation after LC. The entire cross section of gallbladders after 456 LCs was histologically examined. The presence of malignant lesions was confirmed in 13 (2.85%) of 456 cases. The preoperative diagnoses were gallstones in 5 patients, gallbladder polyps in 5, gallstones with gallbladder polyps in 2, and gallstones with adenomyomatosis in 1. The carcinoma had invaded the mucosa in 7, the proper muscle in 2, and the subserosa in 3; the serosa was exposed in 1. The tumor size ranged from 2 mm to the entire gallbladder. An additional resection was performed in 2 patients. During the mean follow-up period of 25.9 months, 1 patient died of recurrence at 8 months while 1 demonstrated recurrence at the port site 1 year after surgery. No other patients have had any recurrence to date. Since early gallbladder cancer removed laparoscopically can be expected to have a satisfactory outcome, diagnostic and therapeutic LC is recommended in cases where total biopsy is indicated. However, in every case, extreme caution needs to be exercised to prevent the dissemination and implantation of cancer cells at the port site.

Aged↗
PubMed1997

Deposition of amyloid beta protein (A beta) subtypes [A beta 40 and A beta 42(43)] in canine senile plaques and cerebral amyloid angiopathy.

To clarify the immunohistochemical features of canine senile plaques (SPs) and cerebral amyloid angiopathy (CAA), the distribution of the amyloid beta protein (A beta) subtypes A beta 40 and A beta 42(43), A beta precursor protein (APP), and glial cell reaction were examined in the brains of seven aged dogs (12-18 years). A beta 42(43) was found to be deposited in all types of SPs, whereas A beta 40 was deposited only in mature (classical and primitive) plaques. CAA, which was located along parenchymal and meningeal arterioles and capillaries, consisted of both subtypes of A beta. APP was exhibited in normal and degenerative neurons and swollen neurites of mature plaques. It was, therefore, considered that A beta 42(43) in diffuse plaques might be derived from APP in neurons, while A beta 40 and A beta 42(43) in mature plaques might be generated from APP in swollen neurites in the plaque. In contrast to the case in humans, in whom deposition of A beta 40 and A beta 42(43) in the mature plaques is predominantly associated with microglial reaction, in dogs we found that it was closely associated with astroglial reaction. The present findings showed characteristics of canine SPs which are different from those of humans.

Aging↗
PubMed1997

Bladder neck support prosthesis: a nonoperative treatment for stress or mixed urinary incontinence.

PURPOSE: We evaluated the usefulness and safety of a bladder neck support prosthesis in patients with stress or mixed incontinence. MATERIALS AND METHODS: A total of 57 women with stress and 20 with mixed incontinence completed a 12-week prospective clinical trial of a bladder neck support prosthesis. While indexes of incontinence episodes, leakage amounts and urgency along with a bothersome index were subjectively evaluated, a 60-minute pad test and urinary flow parameters were objectively evaluated. Three patients scheduled to undergo surgery for stress incontinence voluntarily used the device, and provided urodynamic data and cystourethrograms. Two prongs at 1 end of the ring, a type of elastic vaginal pessary, elevate the bladder neck against the pubic bone and facilitate pressure transmission around the bladder neck, resulting in urinary continence. RESULTS: Four subjective indexes significantly improved. There was no urinary flow obstruction. Urine loss decreased from 20.6 to 4.8 gm. per hour (p < 0.001) on the 60-minute pad test. Of the patients 22 (29%) reported complete continence and 39 (51%) had decreased severity of incontinence by more than 50%. Minor adverse effects occurred in 26% of the patients. Taking subjective evaluation, changes in objective parameters and adverse effects into consideration, 62 patients (81%) had some or maximum benefit according to the global usefulness rating. CONCLUSIONS: The bladder neck support prosthesis is safe, well tolerated and clinically effective for the treatment of stress or mixed incontinence.

Adult↗
PubMed1997

Peripheral blood CD4+CD8+ lymphocytes in cynomolgus monkeys are of resting memory T lineage.

In this study, we analyzed peripheral blood CD4+CD8+ double-positive (DP) lymphocytes in adult cynomolgus monkeys (Macaca fascicularis). Forty of 55 monkeys had > 5% of the peripheral blood DP subpopulation (9.3 +/- 5.9%; mean +/- SD) in peripheral blood lymphocytes (PBL) in contrast to a low percentage of peripheral blood DP cells in humans and mice. In a cross-sectional study, the peripheral blood DP cells were found to increase in proportion with age. To clarify whether peripheral blood DP lymphocytes were immature precursors released from thymus without prior differentiation, the expressions of CD8 chains and CD1b on peripheral blood DP lymphocytes were compared with those on thymocytes. The peripheral blood DP lymphocytes were CD8 alpha + beta- and CD1b-, while thymic DP lymphocytes were CD8 alpha + beta + and CD1b +, suggesting that the peripheral blood DP cells are extrathymic T lymphocytes. Furthermore, the peripheral blood DP lymphocytes exhibited a resting memory T cell phenotype with CD2hiCD3+CD28-CD29hiCD49dhiCD69-CD80lo. Taken together, adult cynomolgus monkeys possess a unique peripheral blood DP T cell subpopulation which expresses a resting memory T cell phenotype. In addition, similar phenotypic properties of DP lymphocytes were distributed in the spleen and lymph nodes, although the proportion was less in the spleen and much less in lymph nodes than in PBL.

Aging↗
PubMed1997

CD4 and CD8 expressions in African green monkey helper T lymphocytes: implication for resistance to SIV infection.

We found that most peripheral CD4 cells co-express a low density of CD8 alpha antigen in African green monkeys (AGM). Further, the cell surface expression of CD4 and the expression of CD4 mRNA underwent a decrease when purified CD4CD8low cells were cultured with mitogen and IL-2. These observations suggest that AGM CD4 cells are subject to loss of CD4 expression after lymphocyte activation. Part of the peripheral CD8 fraction exhibited a significant helper activity which suggested the phenotypic conversion in helper T cells from CD4+ to CD4- in vivo. Simian immunodeficiency virus (SIV) grew well in CD4 panning cells following SIV infection. In contrast, CD4CD8low cells were resistant to SIV infection after their conversion to CD4- cells.

Animals↗
PubMed1997

Displacement of the double-lumen endobronchial tube can be detected by bronchial cuff pressure change.

We measured the bronchial cuff pressure of left-sided double-lumen endobronchial tubes (DLTs) in 54 patients to confirm the effect of DLT displacement on cuff pressure. After positioning the cephalad surface of the bronchial cuff of the DLT 2.5 cm distal to the carina (23 patients in the first part of the study) or just below the carina (23 patients in the second part), the cuff was withdrawn in 0.5-cm steps during right-sided, one-lung ventilation. The bronchial cuff pressure was measured, and the capnogram and pressure-volume loop, displayed by a side-stream spirometer, was evaluated. After positioning the cephalad surface of the bronchial cuff just below the carina (eight patients in the third part), bronchial cuff pressure was measured while confirming the position of the bronchial cuff during the 30 min of the operative procedure. The bronchial cuff pressure decreased significantly by 28.4 cm H2O (P < 0.01) and 21.3 cm H2O (P < 0.01) in the first and second parts, respectively, before the pressure-volume loop or the capnogram changed. The bronchial cuff pressure in the third part showed no significant change. We conclude that bronchial cuff pressure monitoring was very helpful in detecting displacement of the DLT during right-sided, one-lung ventilation.

Adult↗
PubMed1997

Plant 21D7 protein, a nuclear antigen associated with cell division, is a component of the 26S proteasome.

Previously, we cloned a carrot (Daucus carota L.) cDNA encoding a 45-kD protein, 21D7, located in the nuclei of proliferating cells. The 21D7 protein is similar to the partial sequence of a regulatory subunit of the bovine 26S proteasome, p58 (G. DeMartino, C.R. Moomaw, O.P. Zagnitko, R.J. Proske, M. Chu-Ping, S.J. Afendis, J.C. Swaffield, C.A. Slaughter [1994] J Biol Chem 269: 20878-20884) and to the deduced sequence encoded by the Saccharomyces cerevisiae gene SUN2 (M. Kawamura, K. Kominami, J. Takeuchi, A. Toh-e [1996] Mol Gen Genet 251: [146-152]). In our work, the expression of plant 21D7 cDNA rescued the yeast sun2 mutant. Fractionation of carrot and spinach (Spinacia oleracea L.) crude extracts showed that the 21D7 protein sedimented with the active 26S proteasomes. The cessation of cell proliferation in carrot suspensions at the stationary phase caused 26S proteasome dissociation and, correspondingly, the 21D7 protein sedimented together with the free regulatory complexes of the 26s proteasomes. Large-scale purification of carrot 26s proteasomes resulted in co-isolation of the 21D7 protein. Polyacrylamide gel electrophoresis under nondenaturing conditions showed that the 21D7 protein had the same mobility as the 26S proteasome and that proteasome dissociation changed the mobility of the 21D7 protein accordingly. We conclude that the 21D7 protein is a subunit of the plant 26S proteasome and that it probably belongs to the proteasome regulatory complex.

Animals↗
PubMed1997

Long-term efficacy of a self-retaining intraurethral catheter for the treatment of prostatic obstruction.

BACKGROUND: Transurethral prostatectomy is a standard treatment modality for infravesical obstruction with benign prostatic hyperplasia. However, some patients cannot undergo this procedure, so alternative devices or surgical procedures have recently been developed. METHODS: We treated 26 patients with prostatic outflow obstruction by placement of a self-retaining intraurethral catheter (IUC). All patients had coexisting medical complications which contraindicated transurethral prostatectomy. RESULTS: In the short-term, the treatment was successful in 96.2% of the patients, however, longer follow-up demonstrated a significant failure rate, and the 3-year success rate declined to 12.5%. The majority of late failures were associated with urinary tract infections. CONCLUSION: These results showed that although placement of an IUC to treat prostatic obstruction was effective in the short-term, its long-term efficacy was highly limited.

Aged↗
PubMed1997

Biodistribution of cyclosporin encapsulated in liposomes modified with bioadhesive polymer.

The purpose of this investigation was to study the possibility of renewing the immunosuppressive activity of cyclosporin by formulating the compound in liposomes modified with bioadhesive polymers. The liposomes prepared were evaluated both pharmacokinetically and pharmacodynamically. Tissue distribution and plasma pharmacokinetics of cyclosporin and model dye, sudan black, which is as hydrophobic as cyclosporin, were studied in rats after intravenous infusion (10 mg kg-1). The immunosuppressive efficacy of liposomal cyclosporin preparations was studied in the allogenic rat-heart-transplantation model, where cyclosporin therapy (10 mg kg-1) continued for one week. The entrapment of sudan black in liposomes modified with bioadhesive polymers resulted in higher sudan black delivery to the spleen and the liver than with standard sudan-black-loaded liposomes. Among the modified liposomes, those modified with carbopol 941 showed the most remarkable enhancing effect on the delivery of sudan black to these organs and total plasma clearance of sudan black decreased to 38.6 +/- 7.8 mL h-1 kg-1 (standard liposomes, 58.9 +/- 6.4 mL h-1 kg-1). Delivery of cyclosporin to the spleen and the liver was increased approximately twofold by modifying the liposomes with carbopol 941. In the preliminary study on the allogenic rat-heart-transplantation model, the mean survival days of the graft were 18.8 +/- 2.9 days for the group receiving cyclosporin liposomes modified with carbopol 941, 14.2 +/- 4.4 days for the group receiving standard cyclosporin liposomes and 7.6 +/- 0.5 days for the group receiving cyclosporin solution. The encapsulation of cyclosporin in liposomes modified with bioadhesive polymer enhanced the residence time of cyclosporin in the systemic circulation, resulting in approximately twofold greater delivery of cyclosporin to the spleen and liver. However, in the allogenic rat-heart-transplantation model no significant difference was detected between the immunosuppressive efficacy of cyclosporin encapsulated in bioadhesive polymer-modified liposomes and that encapsulated in standard liposomes.

Acrylic Resins↗
PubMed1997

Effects of 6-chloro-2',3'-dideoxyguanosine (6-Cl-ddG) in surface lymph nodes of rhesus monkeys (Macaca mulatta) chronically infected with simian immunodeficiency virus (SIVmac239).

We studied the effects of 6-chloro-2',3'-dideoxyguanosine (6-Cl-ddG), an antiretroviral drug, in surface lymph nodes of rhesus monkeys (Macaca mulatta) chronically infected with simian immunodeficiency virus (SIV). The rhesus monkeys were treated with 25 mg/kg of 6-Cl-ddG every 8 hr for 2 weeks. We performed sequential biopsies of the surface lymph nodes three times: before, during, and after the drug treatment. The 6-Cl-ddG dramatically decreased the number of infectious virus (measured by limiting dilution assay) in lymph node mononuclear cells. This decrease was consistent with the decrease in the number of viral RNA-positive cells in lymph nodes (analyzed by in situ hybridization). Histopathological analysis revealed that hyperplastic lymphoid follicles were reduced in size, especially, enlarged areas of centroblasts in lymphoid follicles (the so-called dark areas of germinal centers) were declined. Our results demonstrated that 6-Cl-ddG decreased the viral burden concomitantly with reduced hyper-activation of germinal centers in lymphoid follicles of SIV-infected rhesus monkeys.

Animals↗
PubMed1997

Changes in normal vaginal flora of African green monkeys (Cercopithecus aethiops) during the menstrual cycle.

Changes in normal vaginal flora of African green monkeys associated with the estrous cycle were examined by the swab method. Bacteroidaceae, corynebacteria, and streptococci were predominant throughout the whole estrous cycle, although individual differences were great. It was also clear that all bacterial species tended to decrease in the menstrual phase. Lactobacilli, the most predominant bacteria in the normal vagina of humans, were detected only in very low numbers in the African green monkey, suggesting that the normal vagina of the African green monkey has a different ecosystem from that of normal human vaginal flora.

Animals↗
PubMed1997

Efficacy of 6-chloro-2',3'-dideoxyguanosine (6-Cl-ddG) on an ARC/AIDS rhesus macaque (Macaca mulatta) infected with simian immunodeficiency virus.

The efficacy of 6-chloro-2',3'-dideoxyguanosine (6-Cl-ddG) was investigated in vivo by using a male ARC/AIDS rhesus macaque infected with simian immunodeficiency virus (SIVmac251/32H). He was administered subcutaneously 6-Cl-ddG (50 mg/kg B.W.) every 8 hr for 14 days when he showed clinical features of recurrent weight loss, severe diarrhea and neuropathy. The number of CD4+, CD8+ cells and total T cells increased rapidly after administration of 6-Cl-ddG and a high level was maintained for 2 months, but the B cell count decreased during the treatment. The antibody titer to SIV did not change significantly during or after the treatment, but the virus load in the plasma measured by RT-PCR dropped to one-third at the start of the 6-Cl-ddG treatment. Within 3 days after the start of 6-Cl-ddG administration, he began to show recovery in clinical signs including weight increase, and disappearance of diarrhea and neuropathy. These findings suggested that 6-Cl-ddG was effective at the stage of ARC/AIDS in a rhesus monkey infected with SIV.

Animals↗
PubMed1997

Malignant lymphoma induction in rabbits by oral inoculation of crude virus fraction prepared from Ts-B6 cells (cynomolgus B-lymphoblastoid cells harboring Epstein-Barr virus-related simian herpesvirus).

Malignant lymphoma was induced in Japanese (JWY), New Zealand (NZY) and Dutch (DUY) white rabbits by oral spray of cell-free pellets of culture fluid (crude virus fraction) of Ts-B6 cells (cynomolgus monkey B-lymphoblastoid cells harboring Epstein Barr virus-related simian herpesvirus or Cyno-EBV). Nine of 11 inoculated rabbits developed malignant lymphomas within 42-160 days after oral inoculation (JWY, 2/3; NZY, 5/6; DUY, 2/2). In contrast, none of the control rabbits inoculated in the same fashion with B95-8 (EBV-producing marmoset cell line) cell-free pellets developed malignant lymphoma. Most rabbits showed increased anti-VCA IgG and anti-EA-DR IgG antibody titers after inoculation by oral spray of Ts-B6 cell-free pellets. EBV-encoded RNA-1 was revealed in the tumor cells by in situ hybridization. EBV DNA was detected in the rabbit peripheral blood leukocytes (PBL) by polymerase chain reaction; the earliest positive result was obtained only two days after oral inoculation. These data suggest that orally administered Cyno-EBV in Ts-B6 cells infects PBL and then induces malignant lymphoma in rabbits. The availability of this animal model promises to clarify the role of EBV in human lymphoma and provides a means for studying prophylactic and therapeutic regimens.

Administration, Oral↗
PubMed1997

In vitro fertilization of follicular oocytes by frozen-thawed spermatozoa in Japanese monkeys (Macaca fuscata).

We report the cryopreservation of epididymal spermatozoa and in vitro fertilization for Japanese monkeys (Macaca fuscata). Ovarian stimulation of seven monkeys was studied by the administration of equine chorionic gonadotrophin (eCG) and human chorionic gonadotrophin (hCG) during the nonbreeding season, after which oocytes were collected from ovarian follicles. The oocytes were subjected to in vitro fertilization by the frozen-thawed epididymal spermatozoa collected from a male monkey during the nonbreeding season. Before the experiment the epididymides and oocytes were transported about 500 km, during which the epididymides were kept in mineral oil to prevent drying and the oocytes were kept in a maturation medium. This technique of cryopreservation and in vitro fertilization has a wide applicability in nonhuman primate reproduction, including the treatment of infertility and the preservation of wild, nonhuman primates.

Animals↗
PubMed1997

[Life-threatening ventricular tachyarrhythmia after CABG in a patient with poor LV function--an experience with the implantable cardioverter defibrillator].

A 52-year-old man with reduced left ventricular function (ejection fraction 0.27) due to myocardial infarction, underwent coronary artery bypass grafting (CABG; LITA-LAD, free RITA-4PD) for angina pectoris. He had suffered from recurrent sustained ventricular tachycardia (VT) since 5 hours after CABG. This arrhythmia was resistant to various antiarrhythmic agents such as Lidocaine, Mexiletine, Disopyramide, Procainamide and Propafenone. He required mechanical circulatory supports (intra-aortic balloon pumping and percutaneous cardiopulmonary support) for the maintenance of hemodynamics during repeated VT that required cardioversions of a total of 441 times during 18 days. Following the administration of Amiodarone, the VT was successfully suppressed. However, he had repeated episodes of VT on exercise, thus, he underwent insertion of the implantable cardioverter-defibrillator at the 98 post-operative day, and he was successfully discharged at the 134 post-operative day after CABG. The instrument was verified to be normal in function after the VT induction test.

Coronary Artery Bypass↗