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Biomedical subjects

T Kosaka

Publications and source records attributed to T Kosaka.

At least 163 records · Page 9Linked to original sources
PubMed1994

In vivo visualization of oxygen transport in microvascular network.

Oxygen transport from the blood to the tissues is a diffusive process driven by the gradient of oxygen tension (PO2). We developed an oxygen-quenching fluorescent membrane that allowed visualization of the PO2 distribution near the microvessels as optical patterns on the membrane by epifluorescence microscopy. This membrane was highly gas permeable to allow PO2 measurement and was transparent enough to also permit observation of the microcirculation. In combination with a newly devised gastight chamber and a micropositioning system, this membrane technique made it possible to visualize the PO2 distribution in the rat mesenteric microvascular network under well-defined conditions. Our preliminary findings indicate that the oxygen distribution in the microvascular network is heterogeneous and suggest that there is considerable release of oxygen from the arterioles. The time lag of the system for tracking rapid PO2 changes in vitro was shown to be negligible, indicating that dynamic PO2 changes occurring in vivo can also be assessed. This technique should provide a novel tool for the study of oxygen transport and metabolism under normal and abnormal conditions.

Animals↗
PubMed1994

[Conception rate and embryo development in guinea pigs with synchronized estrus induced by progesterone implant].

Observations were made on the timing of mating and the pre-implantation development of fertilized eggs in guinea pigs synchronized by long-term progesterone treatment. Females received a subcutaneous implant of progesterone-filled silastic tubing for 14 days. Copulation was observed from the evening of day 4 to the morning of day 6 in 53 of 54 females (98%). Most of them (47/53, 89%) copulated on day 5 after removal of the tubing. Designating the day of copulation (day 5 after removal of the tubing) as day 0 of gestation, embryos collected from the genital tract were at the 4-cell, 8-cell, morula, and blastocyst stages on days 1, 3, 4 and 5 of gestation, respectively. Eggs were recovered at high incidence (85-100%) from days 1 to 5 of gestation. On day 6 gestation, no eggs were recovered from the genital tract, suggesting that implantation had occurred. The mean litter size (+/- S. D.) was 4.0 +/- 0.8 pups, which were born normally after a mean gestation period of 67 +/- 1 days in 7 synchronized females. Since the female guinea pigs synchronized by the long-term progesterone treatment had normal reproductive ability similar to that of cyclic females, this technique would make it possible to obtain animals at a scheduled time even in smaller-sized colonies. In addition, observations on the pre-implantation development of embryos in females with synchronized estrus might be a useful aid in the field of reproductive research.

Animals↗
PubMed1994

[Two cases of hepatic metastasis of colorectal cancer treated effectively by intrahepatic arterial infusion immunotherapy using OK-432, rIL-2, MMC and 5-FU].

Two cases of hepatic metastasis of colorectal cancer were treated effectively by intrahepatic-arterial infusion immunotherapy using OK-432 (2 KE/week or 2 weeks), recombinant IL-2 (35 x 10(4) JRU or 40 x 10(4) JRU/week or 2 weeks), MMC (4 mg/week or 2 weeks) and 5-FU (250 mg/day during admission, 250 mg/week or 2 weeks during outpatient treatment). The levels of CEA were decreased from 17.2 ng/ml to 2.4 ng/ml after 8 weeks in the first case (50 y. o. male) and from 521 ng/ml to 66 ng/ml after 8 weeks in the second case (36 y. o. female), respectively. Abdominal CT revealed a partial response for 11 months in the first case and 6.5 months in the second case.

Adult↗
PubMed1994

[Methotrexate/5-fluorouracil therapy in gastric cancer with peritoneal metastasis].

Eighteen patients with gastric cancer with peritoneal metastasis were treated with methotrexate/5-fluorouracil sequential therapy. In four patients, a partial response was obtained and in another four, symptomatic relief was obtained by the therapy. As side effects, BM suppression was seen in 9 and GI symptoms in 6 patients. Intraaortic, low-dose and 3-hour-interval procedure are recommended in the therapy.

Adenocarcinoma↗
PubMed1994

[The effects of long-term topically applied prostaglandins on aqueous protein concentration and the rabbit ciliary process].

I examined the effects of topically applied prostaglandin (PG) and novel PG-related compounds on the blood-aqueous barrier (BAB) in the rabbit eyes. Latanoprost (PhXA41), PGF2 alpha-isopropyl ester (PGF2 alpha-IE) or PGE2 were topically applied once only or once daily for 8 weeks. Aqueous flare was measured with a laser flare cell meter. After the repeated application for 8 weeks, the morphological changes of the ciliary portion of ciliary processes were investigated with horseradish peroxidase (HRP) as a protein tracer. PGF2 alpha-IE 1.5 microgram, 3.0 micrograms, PGE2 1.5 microgram caused an initial rise of aqueous flare, but PhXA41 1.5 microgram caused no aqueous flare rise. After the application of PhXA41 1.5 microgram or PGF2 alpha-IE 1.5 microgram for 8 weeks, no morphological changes in the ciliary portion of ciliary process were found. After PGF2 alpha-IE 3.0 micrograms or PGE2 1.5 microgram for 8 weeks, HRP passed through the tight junction of non-pigmented epithelial cells and there was dilatation of rough-surfaced endoplasmic reticulum in the non-pigmented epithelial cells.

Administration, Topical↗
PubMed1993

Axons and axon terminals of cerebellar Purkinje cells and basket cells have higher levels of parvalbumin immunoreactivity than somata and dendrites: quantitative analysis by immunogold labeling.

The immunointensities of calcium-binding proteins parvalbumin (PV) and calbindin D28K were quantified in different parts of Purkinje cells and interneurons (basket cells and stellate cells) of the rat cerebellum. An electron microscopic, postembedding immunogold procedure on Lowicryl K4M-embedded thin sections was applied. Neuronal profiles were identified by double-labeling immunocytochemistry using the combination of the two primary antibodies, mouse monoclonal anti-rat calbindin D28K and rabbit polyclonal anti-rat PV. The secondary antibodies were conjugated with colloidal gold of different sizes (10 and 15 nm diameter). In the cerebellar cortex, double-labeled profiles were identified as Purkinje cells and profiles labeled only with anti-PV were identified as inteneurons. The densities of gold particles were used for statistical comparison of the relative levels of PV and calbindin D28K in somata, dendrites, dendritic spines, axons and axon terminals of Purkinje cells, and interneurons. The axons and axon terminals of Purkinje cells and basket cells had significantly higher levels of PV immunoreactivity than Purkinje cell somata, primary, secondary, and tertiary dendrites, and dendritic spines, as well as interneuron somata. On the other hand, the present study could not determine conclusively whether calbindin D28K was distributed homogeneously throughout soma, dendrites, and axons of Purkinje cells or was also concentrated in Purkinje cell axons. To estimate absolute PV concentrations, we made a series of artificial standard samples which were aldehyde-fixed 10% bovine serum albumin containing given concentrations of PV (0, 12.5, 25, 50, 100, 200, and 400 microM, 1 and 2 mM), and calibration curves were deduced from quantitative immunogold analyses of these standard samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Multifocal intraductal papillary adenocarcinoma of the pancreas: report of a case.

This paper describes a case of a mucin-producing tumor of the pancreas, histologically diagnosed as multifocal intraductal papillary adenocarcinoma. The patient had a markedly dilated main pancreatic duct, detected by ultrasound (US) and computed tomography (CT), and endoscopy showed a papillary tumor projecting from the patulous orifice of the enlarged papilla of Vater. Several biopsies taken from the tumor indicated a diagnosis of papillary adenocarcinoma. Total pancreatectomy was thus performed, revealing a multifocal papillary tumor growing along the main duct in the head, body, and tail of the pancreas. Microscopically, these multiple tumors were found to be mucin-producing papillary adenocarcinoma of the main and subsidiary pancreatic ducts with nodular and microfocal periductal invasion. The surgical treatment of multifocal tumors, may therefore necessitate total pancreatectomy to achieve curative resection, in some cases.

Adenocarcinoma, Mucinous↗
PubMed1993

Immunohistochemical detection of prostaglandin I2 synthase in various calcified tissue-forming cells in rat.

Localization of prostaglandin (PG) I2 synthase immunoreactivity was examined in demineralized sections of rat pulpal, periodontal and skeletal tissues using isn-1, a monoclonal antibody raised against the enzyme. Various calcified tissue-forming cells, i.e. odontoblasts, osteoblasts, osteocytes, cementoblasts, cementocytes and chondrocytes, were similarly immunoreactive for PGI2 synthase, suggesting that they are capable of producing PGI2. In odontoblasts and chondrocytes, the reactivity increased gradually with maturation. Weak immunoreactivity was also observed in endothelial cells and fibroblast-like cells in pulpal and periodontal tissues. However, no reactivity was seen in ameloblasts. These results suggest the possible involvement of PGI2 in the regulation of the metabolism of various calcified tissues. Monoclonal antibodies such as isn-1 may become useful markers of the maturation of calcified tissue-forming cells of mesenchymal origin.

Animals↗
PubMed1993

Variations of collateral branching in the motor nerve fibers in the skeletal muscle of adult rats.

Collateral branching (CB) applies to a collateral branch resulting in the innervation of two or more muscle fibers by one motor axon. Using a silver impregnation with or without cholinesterase (ChE) staining, the morphological pattern of innervation was investigated in the motor endplates of the adult rat soleus. Two types of variations of CB, type A and B, were noted. In type A (elaboration of CB), marked ramification of a single motor axon results in double, discrete endings (main and smaller accessory endings) on one muscle fiber and collateral formation on the other. The accessory endings were apposed by some small, clearly-defined separated units of the postsynaptic ChE site. In type B (double endings per endplate), small endings lying close to the main ending were either due to ramification of the motor axon innervating the neighboring muscle fiber (type B 1) or due to direct contact of non-branched, non-original motor axons (type B 2). The incidence of CB and its variations was small and the number of subterminal axons innervating more than one muscle fiber (functional terminal innervation ratio) was far below the level of partial denervation. In response to the local events of muscle, either type A or type B branching could serve as a useful tool to remodel the motor endplate for, e.g., its renewal, replacement and/or enlargement.

Animals↗
PubMed1993

Effects of 2-carboxythylgerumanium sesquioxide (Ge-132) as an immunological modifier of post-surgical immunosuppression in dogs.

The effect of 2-carboxythylgerumanium sesquioxide (Ge-132) as an interferon-gamma (IFN-gamma) inducer on post-surgical immunosuppression was evaluated from the immunological response augmented in canine neutrophils, macrophages and peripheral blood lymphocytes (PBL) using the chemiluminescence technique. Experimental gastrotomy was performed on dogs in two groups; one group was subjected to sham-surgery without any medication, and the other was treated by Ge-132 administration at 24 hr before operation. Although the phagocytic activities of neutrophils, macrophages and PBL in the sham-operated group were depressed transiently after surgery, those in the Ge-132-administered group (Ge-132 group) were enhanced for a long time after surgery. It appeared that the generated free radical, which blocked the phagocytosis of macrophages and PBL, was activated by IFN-gamma. These results suggest that Ge-132 pre-treatment may be efficacious and useful in preventing the multifaceted clinical symptoms induced by post-operative immunosuppression in dogs.

Animals↗
PubMed1993

Copulatory behavior of sexually inexperienced male guinea pigs paired with synchronized estrus females.

The copulatory behavior in sexually inexperienced male guinea pigs aged 12 weeks was observed under dim red illumination. The synchronized estrus females, which were used for receptive females, received a subcutaneous implantation of progesterone-filled tubing for 2 weeks, followed by 0.5mg progesterone injection. Females given these treatment exhibited the lordosis behavior at 19:00 and 21:00 h on 4th day, and had ovulated by 09:00 h on 5th day after removal of implant. During a 2-hrs test session, standard measures of copulatory behavior were recorded. The ejaculation could be observed within the first 30 min in 6 of 7 males. The mounts, intromissions and ejaculation in male guinea pigs were shown in a lower frequency and longer latency than those of rats and hamsters.

Animals↗
PubMed1993

A closed chamber for intravital microscopy of the rat mesentery under controlled oxygen tension and temperature.

An airtight and watertight closed chamber for intravital microscopy of the rat mesentery was developed. It incorporates an oxygen microelectrode and a thermistor for monitoring the local environment around the mesentery, as well as a heater for controlling the chamber temperature. This chamber provides an alternative to the superfusion method for intravital microscopy of the mesenteric microcirculation under circumstances where well-defined experimental conditions are required.

Animals↗
PubMed1993

Correlation between DNA ploidy and clinical features in smooth muscle tumors of the gastrointestinal tract.

Paraffin-embedded tissue samples from 51 surgically resected, gastrointestinal smooth muscle tumors (10 leiomyomas, 5 leiomyoblastomas and 36 leiomyosarcomas) were assayed for nuclear DNA content, and the results were examined for correlation with clinico-pathological variables (tumor size, cellularity and mitosis) and prognosis. Twenty-four (47%) of the 51 tumors, consisting of 3 (30%) of the 10 leiomyomas, 2 (40%) of the 5 leiomyoblastomas and 19 (53%) of the 36 leiomyosarcomas, were identified as aneuploid. A close correlation was found between the mitotic index and the tumor size ( = 0.528; P < 0.001). The DNA ploidy pattern of the leiomyosarcoma was closely correlated with the patient survival periods (P = 0.06). The estimated median survival period was 73 months for patients with diploid tumors, and 51 months for those with aneuploid tumors. The 10-year survival rate for aneuploid tumors was lower than that for diploid tumors (P < 0.001). The measurement of DNA content may provide an index of prognostic value in gastrointestinal leiomyosarcomas.

Adult↗
PubMed1993

[A case of radiation cataract resulting from accidental irradiation of radioisotope].

We studied light and electron microscopic findings in one case of cataract resulting from accidental radioisotope irradiation. A 53-year-old male, a radiographer, was irradiated by Ga-citrate which dropped accidentally into his left eye during a radioisotope procedure. Subsequently opacity appeared in the posterior and anterior subcapsular area of the left lens and increased in intensity. Intracapsular cataract extraction was performed one and a half years after the accident. The extracted lens was studied by light and transmission electron microscopy. Epithelial cells showed frequent stratification in some sites and disappeared in others in the equatorial region. Wedl cells and vacuoles were also seen in the posterior subcapsular area. Degeneration of lens fibers, including multilayered whorls, were observed in the cortex.

Accidents, Occupational↗
PubMed1993

[Intraarterial infusion chemotherapy for recurrent or unresectable gastric cancer].

Sixteen patients with recurrent or unresectable gastric cancer were treated by intraarterial infusion chemotherapy. The tip of the catheter was located at the 9-10th Th level in the aorta of 14 patients and in the common hepatic artery of two. The drug combination was methotrexate + 5-fluorouracil (5-FU), cisplatin, mitomycin C (MMC) + etoposide and MMC + 5-FU. Side effects such as bone marrow suppression, diarrhea and appetite loss were seen in 63% (10/16). The response rate was 36% (4/11) in those who were evaluated, and another three showed relief from symptoms. Median survival time was 11 months, and the one year survival rate was 41%, while two patients showing PR have been alive for more than one year.

Adult↗