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Biomedical subjects

K Takegoshi

Publications and source records attributed to K Takegoshi.

35 records · Page 2Linked to original sources
PubMed1997

Selective homonuclear polarization transfer in the tilted rotating frame under magic angle spinning in solids.

An application of the R2TR method (1995, Chem. Phys. Lett. 232, 424) to selective homonuclear polarization transfer under magic angle spinning is proposed. It is shown that, for a spinning speed fast enough to remove the maximum homonuclear dipolar coupling constant omegaD involved, the flip-flop and flop-flop mechanisms are suitable for recoupling the spins with a chemical shift difference larger than omegaD and a difference comparable to or smaller than omegaD, respectively. It is also shown that, for fast polarization transfer, the off-resonance frequencies should be much higher than the RF intensity in the flip-flop condition, while for the flop-flop condition, the off-resonance frequencies should be much lower than the RF intensity. Some one- and two-dimensional experiments are proposed by utilizing the capability of the R2TR method to abruptly switch on and off the recoupling condition, and are demonstrated for triply 13C-enriched l-alanine. The mixing time required for population transfer was found to be ca. 0.5 ms for the methine and methyl 13C spins separated by 1.5 A and ca. 5 ms for the methyl and the carboxyl carbons separated by 2.5 A. The experimental results and theoretical simulations show that selective polarization transfer is achieved when the difference in the isotropic chemical shifts between the relevant pair of spins and a neighboring spin is more than 1000 Hz.

Alanine↗
PubMed1993

Non-specific immunological abnormalities and association of autoimmune diseases in idiopathic portal hypertension. A study by questionnaire.

A large survey by questionnaire of idiopathic portal hypertension (IPH) in Japan disclosed that 11.9% of 160 cases were associated with one or two autoimmune diseases, and 26.3% of them disclosed hypergammaglobulinemia. Patients with IPH also frequently showed one or more autoantibodies in the serum, such as antinuclear or anti-smooth muscle antibodies. These findings overlapped frequently in the same patient. These data imply that immunological disturbance and/or chronic antigenic stimulation are related to the pathogenesis of IPH, though the exact immunological mechanisms remain unclear. It will be necessary to study more specific immunological reactions in IPH.

Autoantibodies↗
PubMed1991

Human T-lymphotropic virus type 1-associated myelopathy and primary sclerosing cholangitis.

We report the first case of human T-lymphotropic type 1-associated myelopathy (HAM) linked with primary sclerosing cholangitis (PSC). The patient, a 44-year-old woman, also suffered from ulcerative colitis and polyarthritis. Two years and nine months after the clinical onset of PSC, the coexistence of HAM was shown by neurological manifestations characterized by slowly progressive symmetrical myelopathy, predominantly involving pyramidal tracts, and positive antibodies to human T-lymphotropic virus type 1 in serum as well as in cerebrospinal fluid.

Adult↗
PubMed1989

Drug-induced mononucleosis-like hepatic injury in a patient with systemic lupus erythematosus.

A case of systemic lupus erythematosus (SLE) with mononucleosis-like hepatic injury was described. An emergent cesarean section was performed in a 25 yr-old house wife at 34 weeks gestation, followed by administration of several antibiotics. After the surgery she complained of high fever, hepatomegaly and dull right hypochondralgia, and mild liver dysfunction was also found. The liver biopsy showed prominent mononuclear cell infiltration in the sinusoids with minimum hepatocellular necrosis and mild triaditis, resembling hepatic lesion in infectious mononucleosis (mononucleosis-like injury). There were no clinical and serological features suggestive of infectious mononucleosis. This hepatic lesion was thought to be a manifestation of allergic reaction to drugs to which the lymphocyte stimulation test was found to be positive. Immunological abnormalities inherent in SLE might be related to occurrence of such allergic drug reaction.

Adult↗
PubMed1989

[The clinical usefulness of portal venous flow ratio by hepatic angiography with 99mTc-Sn colloid in chronic liver diseases: a comparison with histological finding].

The ratio of portal venous to hepatic blood flow was measured in chronic liver diseases by radionuclide angiography with 99mTc-Sn colloid and its clinical value was discussed. The ratio was proportionally decreased to the progression of the diseases (normal 74.5 +/- 7.3%, chronic hepatitis 58.8 +/- 9.2%, compensated liver cirrhosis 29.3 +/- 19.3%). In alcoholic liver diseases, the standard deviation of the ratio was large as 52.7 +/- 23.7%, and the low ratio in the early period of the disease increased within one or two months as the disease recovered. In comparison with the histological findings of the liver, the ratio in the alcoholic liver diseases was well correlated with the severity of liver fibrosis and liver cell swelling. In conclusion, this noninvasive and simple method is valuable in diagnosing the chronic liver disease, especially alcoholic liver diseases, and also in estimating its clinical course.

Chronic Disease↗
PubMed1988

Light and electron microscopic study of the liver in paraquat poisoning.

Intrahepatic cholestasis in paraquat poisoning in man has been thought to be secondary to extensive bile duct injuries, though its exact mechanism remains unsettled. We have examined liver biopsy specimens from two cases of paraquat poisoning. Case 1 (fatal) presented severe intrahepatic jaundice, and liver biopsy showed centrilobular cholestasis with extensive bile duct loss. Ultrastructurally, dilatation of bile canaliculi with decrease of microvilli and thickening of pericanalicular ectoplasm was found in the hepatocytes. Case 2 (alive) showed mild liver dysfunction without jaundice. While liver biopsy showed nonspecific reactive changes with intact bile ducts and ductules, electron microscopy disclosed dilatation of bile canaliculi with decrease of microvilli and thickening of pericanalicular ectoplasm in the hepatocytes, suggesting that damage to the bile secretory apparatus in the hepatocytes develops irrespective of extensive bile duct loss. These findings suggest that bile secretory apparatus in the hepatocytes as well as biliary epithelial cells could be a target of paraquat or its metabolites.

Adult↗
PubMed1986

A case of Venoplant-induced hepatic injury.

The first case of hepatic injury induced by Venoplant, extracts of Aesculus Hippocastanum, having antiinflammatory activities, was described. A 37 yr-old man was admitted for treatment of pathological fracture of the left brachial bone. He had been received 65 mg Venoplant at another hospital several hours before admission. 17 days later, a liver function test showed mild abnormality and 60 days after injection, he complained of pruritus and jaundice. Laboratory studies revealed moderate elevation of total bilirubin, ALP, gamma-GTP and mild eosinophilia. CT studies and ERC showed no signs of extrahepatic obstructive jaundice. The lymphocyte stimulation test was positive. The liver biopsy demonstrated marked cholestasis with zonal necrosis in the centrilobular areas but showed little or no changes in the portal tracts. These features are consistent with drug-induced hepatic injury.

Adult↗