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Biomedical subjects

G Lin

Publications and source records attributed to G Lin.

At least 181 records · Page 10Linked to original sources
PubMed1991

Role of aorto-angioplasty in hypertension caused by Takayasu's arteritis.

Sixteen patients with Takayasu's arteritis and a long-stenotic segment of the descending thoracic aorta and/or proximal and middle portion of the abdominal aorta, with or without renal artery stenosis, were treated by percutaneous transluminal aorto-angioplasty (PTAA). These patients might be subdivided into three groups: A. with normal renal artery, B. with severe renal artery stenosis or occlusion without treatment or with failure of dilatation, and C. with renal artery stenosis but relieved by percutaneous transluminal renal angioplasty (PTRA). It was found that the hypertension may be caused by the suprarenal aortic stenosis itself. PTAA has an excellent effect to normalize the blood pressure in Group A. The elevated blood pressure may also be decreased in various extent in the patient with severe renal artery stenosis after PTAA, but not to normal. An additional PTRA or other renal vesel reconstruction procedure is necessary in this group. No recurrence of the aorta stenosis was found by non-invasive examinations or aortography during the long-term follow-up. PTAA may be considered as the first choice for the aortic stenosis caused by Takayasu's arteritis.

Adolescent↗
PubMed1991

[Study on targeting drug delivery system--the animal behavior in vivo after hepatic arterial embolization of methotrexate microsphere].

The cross-linked MTX-gelatin microsphere was chosen as an experimental model. Pharmacokinetics and biodegradable period of the microsphere were studied after hepatic arterial embolization in vivo in dogs. After hepatic arterial infusion, the concentration of MTX-ms in peripheral vein blood increased rapidly and declined slowly. In contrast, the peak time of the drug concentration of infused MTX solution appeared at once and decreased rapidly. The half-life of MTX-ms in vivo was 2.14 times as much as that of MTX solution. During the assay period of sixteen hours the drug concentration of MTX-ms in hepatic vein blood was constantly higher than that of MTX solution. The follow-up angiography revealed that microsphere is a kind of peripheral embolic agent and its degradable time in vivo is about one month. Both sustained release and embolization effectiveness of microsphere will be significant in treatment of hepatic cancer.

Animals↗
PubMed1990

Effects of mobile phase composition on the reversed-phase separation of dipeptides and tripeptides with cyclodextrin-bonded-phase columns.

The effects of mobile phase composition on the reversed-phase separation of several dipeptides and tripeptides with a gamma-cyclodextrin-bonded-phase column have been studied. The addition of organic modifier (i.e. methanol) into the aqueous buffer (pH 4.65) mobile phase causes a minimum capacity factor value to be observed for each peptide. This is interpreted to result from two retention mechanisms involved in the separation. The adsorption process causes the retention time to decrease as the water content in the mobile phase is increased. The inclusion process acts in the opposite fashion. The presence of Cu(II) salt in the mobile phase allows further modifications of separation selectivity. This is because the peptide conformation changes upon Cu(II) complexation which in turn alter the hydrophobicity and/or inclusion stability of the peptide. The effects of mobile phase pH (3.6-5.6) and ionic strength (0.001-0.06) were not significant in the present application. Studies with a beta-cyclodextrin column show similar results.

1-Propanol↗
PubMed1989

[Significance of umbilical and paraumbilical veins as collaterals in portal hypertension].

Twenty-one postmortem specimens of the liver (18 normal livers, 3 liver metastases) with attached ligamentum teres were investigated using silicone rubber injection technique. In all cases, the paraumbilical veins were demonstrated. They were usually divided into 2 groups, one on the right and the other on the left side of the ligamentum teres, and they terminated in a variable manner into small peripheral portal vein branches in the liver parenchyma. A patent proximal segment of the umbilical vein was found in 7 of the 21 cases. Connections between the umbilical vein and paraumbilical veins were supposed to represent one of the collateral channels in portal hypertension.

Adult↗
PubMed1988

Use of short-chain cyclopentano-phosphatidylcholines to probe the mode of activation of phospholipase A2 from bovine pancreas and bee venom.

A great mystery in the mechanism of phospholipase A2 (PLA2) and many other lipolytic enzymes is the "interfacial activation" induced by micellar but not monomeric substrates. Equally mysterious is the lack of interfacial activation in bee venom PLA2, as opposed to PLA2s from pancreas and other sources. We have probed these problems using the conformationally restricted short-chain cyclopentano-analogues of diacylphosphatidylcholine (Cp-DCnPC, all-trans isomer). In the reaction catalyzed by bovine pancreatic PLA2, Cp-DC8PC behaved differently from DC8PC in that its monomers and micelles showed comparable activities (but lower than the activity of DC8PC). This result suggests that the activity of PLA2 can be regulated by substrate conformation and supports the "substrate conformation model" (Wells, M. A. (1974) Biochemistry 13, 2248-2257), but raises a question as to whether Cp-DC8PC mimics monomers or micelles of DC8PC. Conformational analysis by 1H NMR revealed that monomeric Cp-DC8PC was conformationally restricted near the carbonyl region, a property characteristic of micelles. Thus, monomeric CP-DC8PC can be considered as a conformational analogue of micelles, but the important structural feature lies in the CH2COO region instead of the glycerol backbone. CP-DC8PC was then used to test a previous proposal that the bee venom PLA2 hydrolyzes monomers but not micelles (which would predict little or no activity for Cp-DC8PC since its conformation is micelle-like whether below or above its critical micelle concentration). The results showed that Cp-DC8PC is a relatively good substrate for the bee venom PLA2 in comparison with the pancreatic PLA2. This and other evidence together suggest that the bee venom PLA2 is not sensitive to the conformation of monomeric and micellar substrates and hydrolyzes both monomers and micelles. The results in both PLA2s demonstrate the usefulness of cyclopentano-phospholipids in probing the mechanism of phospholipases and the roles of substrate conformation in the catalysis of PLA2.

Animals↗
PubMed1984

Blood supply of experimental liver tumors after intraarterial embolization with gelfoam powder and absolute ethanol.

Twenty rats with implanted liver tumor were studied. Following baseline angiography, the hepatic artery was embolized with Gelfoam powder or ethanol (n = 12) while the controls (n = 8) did not undergo embolization. Postmortem Microfil perfusion was performed in all livers. Filling of tumor lakes from the portal vein was seen more often in embolized animals than in controls, indicating the potential role of the portal venous system in the supply of dearterialized hepatic tumors. We discuss the possible clinical implication of our results.

Animals↗
PubMed1984

Umbilical and paraumbilical veins in ligamentum teres. Their significance as collaterals in portal hypertension.

Twenty-two postmortem specimens of the liver (18 normal livers, three with liver metastases, and one with liver cirrhosis) with attached ligamenta teres were investigated using silicone rubber injection technique. In all cases, the paraumbilical veins were demonstrated. They were usually divided into 2 groups, one on the right and one on the left side of the ligamentum teres, and they terminated in a variable manner into small peripheral portal vein branches in the liver parenchyma. A patent segment of the umbilical vein was found in 7 of the 22 cases. Connections between the umbilical vein and paraumbilical veins were supposed to represent one of the collateral channels in portal hypertension.

Adult↗
PubMed1984

Portal blood supply of liver metastases.

Using Microfil technique, hepatic arteries and portal veins were injected in four human cadaver livers with metastases of different origin. Specimens were dissected under stereomicroscope and vessels supplying the tumor nodules were traced. In all cases, tumor vessels could be filled from the portal side; in three, the supplying portal branches were rather wide. The findings were correlated with histologic sections.

Hepatic Artery↗