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Biomedical subjects

Atsushi Yoshida

Publications and source records attributed to Atsushi Yoshida.

67 records · Page 4Linked to original sources
PubMed2002

Accumulation of platelets in the lung and liver and their degranulation following antigen-challenge in sensitized mice.

1. Mast cells and basophils are believed to trigger allergic reactions and anaphylaxis. They rapidly release histamine (H), a typical mediator of inflammation, in response to antigens. In the mouse, platelets contain much 5-hydroxytryptamine (5HT), an additional inflammatory mediator, while human platelets contain both H and 5HT. Here, we examined the response of platelets in sensitized mice to antigen challenge. 2. Platelets accumulated in the lung and liver almost immediately after intravenous injection of ovalbumin (OVA), in mice sensitized to it, and platelet degranulation occurred during these reactions. 3. These responses of platelets preceded H release from mast cells and/or basophils, occurred at doses of OVA lower than those inducing H release, and contributed to the signs of shock. 4. We reported previously that intravenous injection into mice of LPS (a membrane constituent of gram-negative bacteria) induces a similar platelet response (accumulation of platelets in the lung and liver) and shock. 5. Blood that has passed through the body (other than the digestive tract) passes first to the lungs before being recirculated by the heart, and blood that has passed through the digestive tract passes next to the liver. Thus, our findings suggest that in addition to their role in haemostasis, platelets, tiny anuclear cytoplasts, may be important in both innate and acquired immunity, and that the lung and liver may be the fronts at which platelets wage war on pathogens.

Anaphylaxis↗
PubMed2002

Long-term venous complications after full-size and segmental pediatric liver transplantation.

OBJECTIVE: To assess the long-term incidence of venous complications, including portal vein and hepatic vein stenoses, in both whole cadaveric and reduced-size cadaveric and living related liver transplants in a pediatric population, and to assess the therapeutic modalities in the treatment of these lesions. SUMMARY BACKGROUND DATA: A shortage in appropriate-sized liver grafts for pediatric patients led to the use of segmental liver grafts, which became the predominant graft used in 325 of 600 (54%) transplants at the authors' institution. To assess the long-term impact of this strategy, the authors examined the incidence of late (>90 days) venous complications and the efficacy of all therapeutic interventions. METHODS: Six hundred pediatric liver transplants were performed in 325 patients, with reduced-size or split (RSS; n = 207), living related (LRD; n = 118), or full-size cadaveric grafts (FS; n = 275) from 1988 to 2000. All transplants identified with late portal vein or vena caval stenoses or thromboses from a cohort of 524 grafts with survival greater than 90 days were reviewed for demographics, symptoms, therapeutic intervention, recurrence, morbidity, and mortality. RESULTS: Fifty lesions were identified in 49 patients (38 portal vein and 12 hepatic vein-cava stenoses). Sex distribution was similar between portal vein and hepatic vein to cava, as was the mean patient age. Portal vein stenoses occurred in 32 LRD, 3 RSS, and 3 FS, while hepatic vein-cava stenoses occurred in 2 LRD, 8 RSS, and 2 FS. In the 38 portal vein stenoses, 9 had prior perioperative portal vein and/or 5 hepatic artery thrombectomies. Portal vein stenoses were identified after bleeding (17/38), ascites (6/38), increased liver function tests (6/38), splenomegaly (5/38), or screening ultrasound (4/38). Portal vein stenosis was associated most often with cryopreserved vein for portal conduits. Excluding conduits, the incidence of late portal vein complications was reduced to 1%. Lesions became symptomatic at a mean of 50.8 +/- 184.2 months posttransplant. All patients underwent venous angioplasty with a 66% (25/38) success rate, while 7 of 25 required further angioplasty and stenting. In the 13 unsuccessful angioplasties, 8 required surgical shunts for complete portal vein thrombosis. Recurrence occurred in 9 patients: all were amenable to stenting. Nine patients (24%) eventually died of sepsis (4) and surgical deaths at shunt or retransplant (5). Hepatic vein-cava stenoses occurred after a mean of 37.2 +/- 35.2 months, presenting with ascites (n = 10), increased liver function tests (n = 2), and splenomegaly (n = 2). All patients were diagnosed by venogram and managed by balloon dilatation alone (n = 6) or stented (n = 4), with an 80% (10/12) success, with two late recurrences amenable to repeat angioplasty or stenting. Long-term survival was 80% at 1 year. CONCLUSIONS: The use of segmental grafts without venous conduits is not associated with a significant rate of long-term venous complication. When late venous complications do occur, venous angioplasty and stenting are both a safe and effective management modality. If necessary, venous angioplasty may be repeated with the placement of a stent. When this is required, care must be taken to place the stent in a position where the metallic object will not interfere with future surgical manipulations should retransplantation be necessary.

Anastomosis, Surgical↗
PubMed2002

Topical administration of HSV gD-IL-2 DNA is highly protective against murine herpetic stromal keratitis.

PURPOSE: To evaluate the immunopreventive effect of eyedrops that contain gD-IL-2 DNA (a chimeric gene of the glycoprotein D gene of herpes simplex virus type I (HSV-1) and human interleukin-2 (IL-2) on murine herpetic keratitis. METHODS: A plasmid containing gD-IL-2 (pHDLneo1) was constructed. The eyedrops containing 90 microg/10 microL of the DNA was instilled bilaterally into the conjunctival sacs of BALB/c mice on days 0 and 7. Three weeks after the last administration, neutralizing antibody, delayed-type hypersensitivity (DTH), and 51Cr-release from infected targeted cells by lymphocytes from the cervical lymph nodes and spleen were determined. Immunized mice were challenged with HSV-1, after which the clinical signs of the corneal epithelia and stroma were scored. RESULTS: Specific neutralizing antibody was raised and prominent DTH reaction was elicited from immunized mice. Lymphocytes obtained from the local lymph nodes and spleen vigorously potentiated the cytotoxic activity against the virus-infected cells. Clinically, the development of stromal keratitis was completely inhibited, but prevention or reduction of HSV-1 epithelial lesions was not demonstrated statistically. CONCLUSION: Topical immunization with a DNA vaccine encoding gD-IL-2 totally prevented the development of herpetic stromal keratitis. This procedure is a simple and convenient method for possible clinical application in the future.

Administration, Topical↗
PubMed2002

Histamine regulation of interleukin-18-initiating cytokine cascade is associated with down-regulation of intercellular adhesion molecule-1 expression in human peripheral blood mononuclear cells.

In the previous study, we demonstrated that interleukin (IL)-18 up-regulated intercellular adhesion molecule-1 (ICAM-1) expression on monocytes in human peripheral blood mononuclear cells (PBMC) and that heterotypic interaction between monocytes/T or NK cells through ICAM-1/LFA-1 intensified the production of IL-12, interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha) in PBMC. In the present study, we demonstrate that histamine inhibited the ICAM-1 expression in monocytes induced by IL-18 using flow cytometry and that the responses of IL-12, IFN-gamma, and TNF-alpha induced by IL-18 were concentration dependently inhibited by coexisting histamine, whereas IL-18-inhibited IL-10 production was reversed by the same concentrations of histamine. The modulatory effects of histamine on ICAM-1 expression and cytokine production were all concentration dependently antagonized by famotidine but not by d-chlorpheniramine and thioperamide, and were mimicked by selective H(2)-receptor agonists but not by H(1)- and H(3)-receptor agonists, indicating the involvement of H(2)-receptors in histamine action. The inhibition of IL-18-induced IFN-gamma by histamine was ascribed to the strong inhibition of IL-12 production by histamine. Histamine thus operates the negative feedback mechanism against IL-18-activated cytokine cascade through the strong inhibitory effect on ICAM-1 expression and IL-12 production in monocytes, contributing to the formation of diverse pattern of cytokine activation from Th1 to Th2, depending on the monocyte/macrophage activation and cytokine environment.

Cell Aggregation↗
PubMed2002

Appendicitis caused by caecal carcinoma: report of a case.

Appendicitis can rarely occur in association with carcinoma of the caecum, particularly in elderly patients. We report a case of acute appendicitis provoked by an adenocarcinoma of the caecum which obstructs the lumen of the appendix in a 58-year-old man. The patient underwent an ileocaecal resection with lymph node dissection. The difficulties of identifying a small tumor at laparotomy and the implication for optimal treatment are emphasized.

Adenocarcinoma↗
PubMedDate not supplied

Impact of aberrant arterial anatomy and location of anastomosis on technical outcomes after liver transplantation.

Variations in donor and recipient arterial anatomy frequently present challenges for surgeons when attempting to establish proper arterial inflow during liver transplantation. We reviewed our data on 233 adult primary liver transplants, conducted from January 1996 through December 2001, to determine the impact of these variations on the outcomes after liver transplantation. Twenty-four (10.3%) arterial complications were encountered at a mean of 2.27 months after transplant. Carrel patches for the anastomoses were not used in 33 patients (14%), which had no relation to arterial complications (P = 0.7). Sixty-one donors (26.2%) had at least one aberrant artery, which had no relation to arterial complications. However, use of donor celiac artery for anastomosis was significantly associated with higher arterial complications (16% versus other choices, P = 0.03). Furthermore, use of common hepatic recipient artery was associated with higher arterial complications (16%, P = 0.03). There were 58 total biliary complications (24.8%). Biliary complications were associated with the presence of arterial complications (P = 0.01). In conclusion, aberrant donor arterial anatomy was not associated with an increased rate of arterial complications; however, choice of location of arterial anastomosis may be a significant factor. Biliary complications were associated with arterial complications.

Adult↗
PubMedDate not supplied

Acromial spur: relationship to aging and morphologic changes in the rotator cuff.

This study's objective is to elucidate the relationship between acromial spur formation and rotator cuff pathology or aging. The subjects comprised 1029 shoulders in control, cadaveric, and operative groups. A radiograph in the supraspinatus outlet view was taken in all subjects. The lengths of the incident spurs were measured and classified into 3 sizes (small, <5 mm; medium, <10 mm; and large, > or =10 mm). The rotator cuff was macroscopically classified as normal or as having bursal-side fraying, joint-side tear, intratendinous tear, bursal-side tear, complete tear limited to the supraspinatus tendon, or massive tear. In the control group, the overall incidence of spurs and spur size increased with advancing age (P < .001), but the majority of spurs were small (<5 mm). In the cadaveric group, the overall incidence did not correlate with advancing age (P > .05). However, spur size increased with age in subjects aged 50 years or older (P < .001). The incidence of spurs in rotator cuffs with bursal-side tears was highest and was significantly higher than that in normal cuffs and cuffs with bursal-side fraying and intratendinous tears. We observed 40% of medium spurs and 69% of large spurs in cases with bursal-side tears, complete tears limited to the supraspinatus tendon, and massive tears. In the operative group, the overall incidence correlated to advancing age (P < .001), reaching 80% or more in subjects aged 30 years or older. In addition, the size of spurs was larger than that in the other 2 groups in all age groups with few exceptions (P < .05). Small spurs were associated with advancing age. Morphologic change to the bursal side of the rotator cuff may enhance spur growth. The presence of a small spur has no diagnostic value for rotator cuff tears. Spurs measuring 5 mm or more, however, are of diagnostic value because of their high rate of association with bursal-side tear, complete tears limited to the supraspinatus tendon, or massive tears.

Acromioclavicular Joint↗
PubMedDate not supplied

Osteoarthritis in shoulders with traumatic anterior instability: preoperative survey using radiography and computed tomography.

The purposes of this report are to determine the incidence of preoperative osteoarthritis in shoulders with traumatic anterior instability and to detect the factors leading to its development. The radiographs and computed tomograms of shoulders in 282 patients with unilateral instability and without previous surgery, whose age was younger than 40 years and who had no possibility of nontraumatic secondary osteoarthritis, were examined by use of a simplified modification of Samilson and Prieto's criteria. Osteoarthritis was found in 32 joints (11.3%) (mild in 30 and moderate in 2) on the radiographs. Computed tomography (CT) revealed arthritic changes in 88 shoulders (31.2%), including all 32 radiographically osteoarthritic joints. The marginal spur of the humeral head initially occurred in the anteroinferior aspect and mainly extended downward. The total number of dislocations and/or subluxations and frequency of dislocation and/or subluxation of 32 radiologically osteoarthritic joints were significantly larger and higher, respectively, than those of 194 non-osteoarthritic joints (P < .02). The total number of dislocations and/or subluxations (P < .01) and the number of subluxations (P < .05) were significantly different between osteoarthritic joints and nonarthritic joints classified by CT findings. The rate detected by CT was higher than those of any other previous radiographic survey that may have underestimated the incidence rate. Most postoperative osteoarthritis cases recognized on radiographs in short-term or midterm follow-up studies are assumed to be preoperatively generated.

Adolescent↗
PubMedDate not supplied

The effect of immunization with herpes simplex virus glycoprotein D fused with interleukin-2 against murine herpetic keratitis.

PURPOSE: To evaluate the preventive effect of vaccination using fusion protein (gD-IL-2) consisting of herpes simplex virus type 1 (HSV-1) glycoprotein D (gD), and human interleukin-2 (IL-2), and plasmid DNA encoding gD-IL-2 against murine herpetic keratitis. METHODS: Plasmid containing gD-IL-2 (pHDLneo1) was constructed, and gD-IL-2 peptide was purified. BALB/c mice were injected hypodermally or subconjunctivally twice with 1 microg/0.1 mL of gD-IL-2 peptide, or subconjunctivally twice with 90 microg/0.05 mL of gD-IL-2 plasmid DNA. Neutralizing antibody titer and delayed-type hypersensitivity (DTH) against HSV-1 were measured. Immunized mice were challenged with CHR3 strain of HSV-1 into the cornea. Clinical manifestations of the epithelial and stromal keratitis were scored. RESULTS: Stromal keratitis was inhibited in gD-IL-2 peptide- or DNA-immunized mice; however, epithelial keratitis was not. It was confirmed that plasmid gD-IL-2 elicited significant virus neutralizing titer in sera and DTH response. CONCLUSION: Vaccination with gD-IL-2 was effective against murine herpetic keratitis.

Animals↗
PubMedDate not supplied

Effects of RGD peptides on cells derived from the human eye.

PURPOSE: To investigate the effects of Arg-Gly-Asp (RGD) peptides on cells derived from the human eye. METHODS: SV40-transformed human corneal epithelial cells (SCE), SV40-transformed human lens epithelial cells (SLE), normal human keratocytes (NK), and human retinal pigment epithelial cells stably expressing human telomerase reverse transcriptase (TRPE) were used. A human corneal cDNA library was screened to isolate the human homologue of p130 Crk-associated substrate (Cas). Next, after these cells were attached to the substratum, RGD-containing soluble tetrapeptides Arg-Gly-Asp-Ser (RGDS) were added to the culture medium and morphological changes were observed. RESULTS: A clone, H-2, consisting of 3228 nucleotides, with a long open reading frame (870 amino acid residues) was isolated, and determined to be the human homologue of Cas. After addition of the RGDS peptides, both SLE and TRPE detached from the plastic culture plate, but SCE and NK did not. Detached SLE and TRPE showed decreased levels of tyrosine phosphorylation in Cas. CONCLUSIONS: These results indicated that the signaling pathway through Cas played an important role in epithelial cell adhesion in the eye.

Amino Acid Sequence↗
PubMedDate not supplied

Determination of precise gamma-ray emission probabilities for 88Rb.

Precise gamma-ray emission probabilities of 88Rb have been measured by 4pi beta-gamma coincidence using a live-timed two-dimensional data-acquisition system. The absolute emission probabilities of the 898.1, 1836.1 and 2677.9 keV gamma rays were determined from the absolute gamma-ray intensities and the disintegration rates to be 14.68+/-0.13%, 22.73+/-0.15% and 2.123+/-0.021%, respectively. The relative intensities were measured for the weak gamma rays by a gamma-ray spectrometer, and the 88Rb decay scheme was determined from these results.

Journal Article↗
PubMedDate not supplied

Isolated pulmonary recurrence after resection of colorectal hepatic metastases--is resection indicated?

BACKGROUND: Resection of colorectal hepatic metastases is an accepted treatment modality for stage IV colorectal cancer. Concurrent or sequential pulmonary metastasectomy continues to be a controversial strategy. We analyzed factors that predicted pulmonary recurrence in patients with resected hepatic metastases and examined the efficacy of these combined interventions in the treatment of metastatic colorectal cancer. METHODS: A retrospective review of a database of patients who underwent resection of colorectal hepatic metastases was performed to identify patients who either had synchronous pulmonary metastases (defined as pulmonary recurrence at the time of or within 3 months of hepatic metastasectomy) or subsequently experienced pulmonary metastases. Patient demographics, operative interventions, and overall survival were analyzed. Statistical methods included unpaired Student's t-test, actuarial survival and log-rank analysis. RESULTS: Twenty-one patients (19%) had pulmonary metastases after hepatic resection, of which 12/21(57%) underwent pulmonary resection. No differences were observed between the resection group, the nine patients with pulmonary metastases who did not undergo resection, and the 87 patients without pulmonary metastases with regard to age, sex, race, or extent of hepatic metastases. When comparing the resected versus the unresected pulmonary recurrences, the disease-free interval from hepatic resection to detection of pulmonary metastases was 21 +/- 20 months (range, 3-72 months) versus 16 +/- 8 months (range, 4-25 months), respectively. All patients with pulmonary recurrence who underwent pulmonary metastasectomy had unilateral disease. Seven of 12 (58%) underwent wedge/segmental resections, and the remaining five (42%) required lobectomy in order to obtain a complete resection. Four patients who underwent pulmonary resection had multiple lung metastases (two to four lesions), and eight had isolated metastasis. There were no perioperative deaths in the pulmonary metastasectomy group. Contraindications to pulmonary resection included extensive pulmonary disease and concurrent extrapulmonary disease. A survival benefit was noted at 3 years for the resected versus the unresected group (60% vs 31%). Survival was no different between the resected pulmonary recurrence patients and the resected hepatic metastases only patients (60% vs 54%). CONCLUSIONS: Pulmonary metastasectomy can be performed safely and effectively in patients with recurrent disease after hepatic resection for colorectal metastases. Prolonged survival can be achieved with resection of isolated pulmonary recurrence after hepatic resection for colorectal cancer. Further studies that delineate selection criteria for pulmonary resection of colorectal metastases are warranted.

Colorectal Neoplasms↗