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Biomedical subjects

T Tani

Publications and source records attributed to T Tani.

407 records · Page 23Linked to original sources

Interferometric measurement of femtosecond optical pulses emitted from a fibre probe.

An interferometric technique is applied to a temporal analysis of the far-field radiation from a near-field optical fibre probe. A balanced homodyne scheme combined with lock-in detection at dual harmonics allows one to evaluate the temporal form of weak signal pulses, even in the presence of some environmental vibrations that disturb the optical interference. The transmission properties of a small aperture are formulated theoretically. It is shown that the sub-wavelength aperture should not distort the femtosecond optical pulses temporally, which is consistent with the experimental observation.

Journal Article↗

Laser scanning gradient index optics microscope: submicrometre scale spectroscopy and imaging at cryogenic temperatures.

A laser scanning far-field optical microscope for low-temperature imaging and spectroscopy based on gradient index optics is presented. A rod-shaped gradient index microlens is used as a zero-working-distance solid immersion objective lens. The obtained lateral resolution is 310 nm of the FWHM at a wavelength of 545 nm. A laser scanning mechanism located outside an optical cryostat enables one to achieve large scanning ranges independent of temperature. The use of the microscope for submicrometre-scale spectroscopy and low-temperature photochemistry performed on molecular J aggregates in thin polymer films is presented.

Journal Article↗

Optical-fibre scanning near-field optical microscope for cryogenic operation.

We have developed a new type of scanning near-field optical microscope (SNOM) utilizing optical fibres. The probe tip is controlled by shear force feedback with a fibre interferometer and signal light is collected directly by a multimode fibre. These features make the SNOM head more compact and less sensitive to vibration. Further advantages of this new type of SNOM are that it obviates the need for optical windows in the cryostat and offers easy optical alignment.

Journal Article↗

Novel mechanical assistance in the treatment of endotoxic and septicemic shock.

Systemic sepsis is a frequent and fatal complication of postoperative patients. More recently, therapeutic trials of plasma or blood exchange are performed in septic patients for the purpose of reducing both endotoxins and albumin-bound toxins. As an alternate approach such as this for the removal of endotoxin directly from the blood, the authors recently developed polymyxin B immobilized fiber (PMX-F) as a biomaterial for selectively detoxifying endotoxin. That this newly invented PMX-F neutralizes a sufficient amount of endotoxin in vitro was reported previously. In ex vivo experiments, direct hemoperfusion by PMX-F was performed on purified endotoxin injected canine and on live Escherichia coli induced septic dogs. Only 5% (1/20) survived in the control group, but 75% (30/40) survived in the treated group. Septic dogs died within 18 hours after bacteria infusion in the control group. But all in the treated group survived 3 days. Forty percent of them survived permanently. These observations indicate that PMX-F treatment, namely selective removal of endotoxin in the endotoxic and septicaemic dogs prolongs or increases the chances of survival. Blood compatibility of PMX-F was also evaluated both in vitro and in vivo. With platelets it was shown to be fairly good and with red blood cells, white blood cells, and proteins, extremely good. A preclinical study on the efficacy and safety of PMX-F throughout widespread experiments has just ended.

Animals↗

The efficiency of new leukocyte removal filters. CF-1 and CF-2.

Two new leukocyte removal filters, Nipro CF-1 and CF-2 (Nipo Medical Industries, Osaka, Japan), were evaluated. These non-woven polyester filters, which are gravity flow devices that require no priming and no rinsing after use, were developed for preparing 400 ml of whole blood or red cell concentrates from 400 ml of whole blood. A flow cytometric technique was developed to measure extremely low white blood cell (WBC) counts. To evaluate the efficiency of these filters, leukocyte counts were measured by three techniques: 1) electronic, 2) visual, and 3) flow cytometry. Flow cytometric counting was done using a Coulter EPICS-C cytometer (Coulter Corp., Hialeah, FL). Nipro CF-1 removed 99.97 +/- 0.01% (mean +/- SD, n = 14) of leukocytes measured by flow cytometry, and CF-1 recovered 90.7 +/- 4.47% (n = 21) of red blood cells. After filtration through CF-2, more than a 6 log10 (> 99.9999%) depletion of WBCs was detected in six samples, a 6 log10 (99.9999%) depletion of WBCs was detected in two samples, a 5 log10 (99.999%) depletion was detected in five samples, and a 4 log10 (99.99%) depletion was detected in one sample. CF-1, in which size and priming volume was smaller than other commercial leukocyte removal filters, accomplished a 3 log10 reduction in WBC count, compared with other commercial filters. CF-2 achieved a 4-6 log10 depletion of WBCs assayed by flow cytometry.

Blood Transfusion↗

Effectiveness of coagulation factor XIII concentrate for reversing loss of tensile strength of rat intestinal anastomoses.

BACKGROUND: Blood coagulation factor XIII (F-XIII) promotes cross-linking of fibrin during blood coagulation. Impaired clot stabilization in patients with genetic deficiencies of F-XIII is associated with marked pathologies of wound healing. METHODS: 60 rats given carbon tetrachloride underwent ileal anastomosis after which they received albumin (Alb animals) or F-XIII concentrate (F-XIII animals) immediately after surgery and daily thereafter until day 2 or 4 and were euthanized on day 3 or 5, respectively, or until day 5 and were euthanized on day 7, 10, or 21. We measured the plasma F-XIII activity and anastomotic tensile strength, followed by immunohistochemical localization of F-XIII subunit A within anastomoses. RESULTS: On day 3, there were no significant differences between Alb and F-XIII animals for plasma F-XIII activity and tensile strength, and both groups of animals showed little immunostaining for F-XIII on anastomoses. Plasma F-XIII activities did not differ between Alb and F-XIII animals on day 5 (115.8 +/- 16.8 vs. 137.3 +/- 14.9%). Although the tensile strength in both groups was increased compared with that of day 3, that in F-XIII animals (129.8 +/- 3.3 gf) was significantly higher than that in Alb animals (100.8 +/- 5.3 gf, p = 0.014). F-XIII animals showed de novo collagen fibers and intense immunoreactivity of F-XIII in the extracellular matrix around the anastomoses. Similar differences occurred on day 7 but not days 10 and 21. CONCLUSIONS: F-XIII concentrate may accelerate the early healing process of intestinal anastomosis because of the protein's accumulation in situ.

Anastomosis, Surgical↗

Prognosis of patients with resection of stage IV gastric cancer.

We retrospectively analyzed 116 patients who underwent resection of stage IV gastric cancer to investigate the prognostic factors responsible for long-term survival. Statistically significant clinicopathological differences between patients surviving 3 years or more (n = 9) and those surviving less than 3 years (n = 107) were observed in regard to macroscopic type, curability of surgery, lymph node metastasis and blood vessel invasion. These four variables also had a statistically significant influence on survival by univariate analysis. Multivariate analysis revealed that no residual tumor (R0) surgery was a significantly beneficial factor for long-term survival. However, no patients with the diffusely infiltrative type of tumor survived for more than 2 years even if they underwent R0 surgery. Patients without the diffusely infiltrative type who underwent R0 surgery had better survival rates: a 27.3% and 13.6%, 3 and 5 year survival rate, respectively. In conclusion, R0 surgery contributes to long-term survival even in stage IV gastric cancer, and some patients with the not diffusely infiltrative type, in particular, may receive a survival benefit by R0 surgery.

Adolescent↗

Kinetics of cytokine gene expression during the in vitro CTL induction against a murine nonimmunogenic tumor.

BACKGROUND: The study of the local environment around tumors, including cellular and endogenous cytokine kinetics may improve our understanding of the biological process occurring during the CTL induction. MATERIALS AND METHODS: The expression kinetics of ten cytokine genes and immune cell subsets were examined by a RT-PCR and immunohistochemistry using a nonimmunogenic murine tumor and its immunogenic variant (A7). RESULTS: In a mixed lymphocyte-parent tumor cell culture (MLTC) using in vivo A7-immunized spleen cells, where CTL induction was confirmed on day 5 of cultivation, IL-6 gene expression was promptly activated at 12 h, IL-2 and IL-4 gene expression was prominently up-regulated on days 1 and 2, and then IL-10 and TGF-beta gene expression was down-regulated from day 2 onward. In contrast, in a MLTC using non-immunized spleen cells (a CTL non-induction model), no prominent upregulation of the IL-6, IL-2 or IL-4 gene was detected, and expression of the IL-10 and TGF-beta genes increased steadily. Although numerous dendritic cells were observed in the A7 immunized spleen tissue, lower numbers of dendritic cells were evident in the non-immunized spleen tissue. CONCLUSIONS: A cellular environment that includes the presence of dendritic cells and a cytokine environment that involves the timely production of IL-6, IL-2, and IL-4, and subsequent inhibition of the immunosuppressive cytokines IL-10 and TGF-beta, appear to play an important role in induction of CTL in this model.

Animals↗

Anomalous pancreaticobiliary ductal junction without bile duct dilatation in gallbladder cancer.

BACKGROUND/AIMS: Anomalous pancreaticobiliary junction is a rare anomaly but is a risk factor for primary carcinoma of the gallbladder. To define the relationship between anomalous pancreaticobiliary junction, especially if it is not associated with common bile duct dilatation, and gallbladder carcinoma, we retrospectively reviewed data of 126 patients with gallbladder carcinoma. METHODOLOGY: All these patients had undergone direct cholangiography either by endoscopic retrograde cholangiopancreaticography or percutaneous transhepatic cholangiography. RESULTS: Among 126 patients with gallbladder cancer, 23 patients (18.3%) exhibited anomalous pancreaticobiliary junction. Patients with anomalous pancreaticobiliary junction were younger (mean age: 54 +/- 9.1 years) than patients without anomalous pancreaticobiliary junction (mean age: 65 +/- 9.7 years). The incidence of gallstones in patients with anomalous pancreaticobiliary junction (17%) was significantly lower than in those without this anomaly (64%) (P < 0.01). Among the 23 patients with anomalous pancreaticobiliary junction, 12 patients (52%) had no bile duct dilatation and, 11 patients (48%) had bile duct dilatation in the form of fusiform or cylindrical dilatation. However, no cases with severe cystic dilatation were found. Patients of anomalous pancreaticobiliary junction without common bile duct dilatation had more advanced disease and poor prognosis than those with common bile duct dilatation. CONCLUSIONS: The present study revealed that gallbladder cancer in the patients of anomalous pancreaticobiliary junction without common bile duct dilatation was diagnosed at advanced stage and the prognosis was very poor. Therefore, if a minor abnormality is detected in the wall of acalculous gallbladder on ultrasonography, direct cholangiography should be done to exclude this anomaly.

Adult↗