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Biomedical subjects

J Jin

Publications and source records attributed to J Jin.

At least 163 records · Page 9Linked to original sources
PubMed1995

Glucosamine 6-phosphate deaminase in normal human erythrocytes.

In the course of an investigation of hexosamine catabolism in the human malaria parasite, Plasmodium falciparum, it became apparent that a basic understanding of the relevant enzymatic reactions in the host erythrocyte is lacking. To acquire the necessary basic knowledge, we have determined the activities of several enzymes involved in hexosamine metabolism in normal human red blood cells. In the present communication we report the results of studies of glucosamine 6-phosphate deaminase (GlcN6-P) using a newly developed sensitive radiometric assay. The mean specific activity in extracts of fresh erythrocytes assayed within 4h of collection was 14.7 nmol/h/mg protein, whereas preparations from older erythrocytes that had been stored at 4 degrees C for up to 4 weeks had a mean specific activity of 6.2 nmol/h/mg. Characterization of the deaminase by chromatofocusing gave a pI of 8.55. The enzyme was optimally active at pH 9.0 and had a Km of 41 microM. The metal chelators EDTA and EGTA were non-inhibitory; however, inhibition was observed in the presence of metal ions, especially Cu2+, Ni2+ and Zn2+. In addition, the deaminase was also inhibited by several sugar phosphates including the reaction product, fructose 6-phosphate.

Aldose-Ketose Isomerases↗
PubMed1995

Portal vein embolization with steel coils and absolute ethanol: a comparative experimental study with canine liver.

Portal vein embolization (PVE) is expected to have an adjuvant effect on the treatment of human liver tumors with transcatheter hepatic arterial embolization (TAE). In this experimental study, PVE was tried using two kinds of embolic materials, steel coils (coils) and absolute ethanol (ethanol). The aim of this article is to compare the effectiveness between the two methods. Five dogs and 12 dogs were treated with coils and ethanol, respectively. The second order portal branches were embolized. Embolization effects of each embolic material on the hepatic vessels and the liver parenchyma were studied angiographically and histologically. PVE with coils achieved immediate occlusion of the embolized vessels in all dogs. Unexpectedly, unembolized vessels were also constricted and/or obstructed in 4 of 5 dogs during a 4-week follow-up period. Histological examination showed no hepatic necrosis in all dogs. By contrast, in the dogs treated with ethanol, venous occlusion was achieved immediately after embolization with ethanol of 0.4 mL/kg or more. The embolized vessels remained occluded and no obstruction of unembolized vessels was observed until 4 weeks after embolization. Hepatic necrosis was observed in the segments where portal veins were occluded. The degree of parenchymal damage was proportional to the injected ethanol dose. Judging from these results, ethanol is likely to be more suitable than coils as an embolic material for PVE. PVE with coils is often dangerous because unembolized vessels might be occluded unexpectedly. For the clinical use of PVE with ethanol, the appropriate dose of injection should be investigated.

Animals↗
PubMed1995

[Prevention of HLA antibody formation in patients with hemato-oncologic diseases by using leukocyte depleted blood preparations].

OBJECTIVE: To determine the effect of transfusion therapy with leukocyte-depleted platelet concentrates in comparison to transfusion support with standard platelet concentrates on the frequency of HLA alloimmunization in hematologic-oncologic patients. DESIGN: Prospective randomized study. SETTING: Institute for Transfusion Medicine and Immunohematology at a University Hospital. PATIENTS: 52 hematologic-oncologic patients randomized in 2 groups. INTERVENTIONS: Exclusive substitution with leukocyte-depleted blood components (platelet concentrates and packed red cells, filter group) or with standard platelet concentrates and leukocyte-depleted packed red cells (control group). Determination of the development of HLA antibodies. RESULTS: 27% of the patients in the control group (4 out of 15) developed HLA antibodies in contrast to zero patients (0 out of 22) in the filter group (p < 0.02). CONCLUSIONS: The results of this comparative clinical study show that the consequent and exclusive support with leukocyte-depleted blood components is an effective approach for prevention of HLA alloimmunization in long-term substituted patients.

Adult↗
PubMed1994

On the field inhomogeneity of a birdcage coil.

A mathematical model is developed for the numerical analysis of birdcage coils constructed using capacitors having different capacitance. With the aid of this model, it is shown that the deviation of some capacitance introduced by tune, balance, and drive mechanisms can cause inhomogeneity in the B1 field produced by the coil. Useful curves and formulae are developed to provide a guideline for the design of birdcage coils.

Algorithms↗
PubMed1994

[Inhibitory effect of taohong siwu decoction on collagen crosslinking, hyaluronic acid cleavaging and lipid peroxidation].

It has been demonstrated by cytochrome C colorimetry that the Taohong Siwu Decoction (TF) is effective in hydroxyl radical scavenging. TBA colorimetry has proved that TF is effective in inhibiting lipid peroxidation. As detected by viscometry hyaluronic acid cleavage induced by hydroxyl radical can be inhibited by TF. It has been demonstrated by SDS-PAGE method that TF is effective in inhibiting collagen crosslinking.

Animals↗
PubMed1993

Comparative analysis of the sequence and structure of two Drosophila melanogaster genes encoding vitelline membrane proteins.

Two Drosophila melanogaster vitelline membrane protein-encoding genes (VM), located at polytene band positions 26A and 34C, have been cloned and comparatively characterized at the nucleotide level. Sequence analysis of genomic and cDNA clones for the two genes, VM26A.1 and VM34C.1, indicates that both are similarly organized with a central highly conserved domain [Scherer et al., Dev. Biol. 130 (1988) 786-788] which is flanked by unrelated regions, and that both genes lack introns. Comparison of the upstream regions reveals that both VM genes contain a hepatmeric element identical to one associated with the D. melanogaster yolk protein-encoding genes (YP). This heptamer occurs in the specific 5' flanking region responsible for ovarian temporal- and tissue-specific control in both VM and YP genes. A putative chorion transcription factor 2 site is also associated with an upstream control element of VM26A.1, but not with any sequenced portion of VM34C.1.

Amino Acid Sequence↗
PubMed1993

Separation of sugars by ion-exclusion chromatography on a cation-exchange resin.

A method for the separation of N-acetylmannosamine and N-acetylglucosamine is described, which consists of chromatography of the two sugars on a column (30 x 1 cm) of the cation-exchange resin, Dowex 50W-X2, in borate buffer at pH 7.8. N-Acetylmannosamine is eluted near the void volume, while N-acetylglucosamine emerges in a more retarded position. It is postulated that the separation occurs as a result of the combined effects of ion exclusion and gel permeation. Thus, in borate solution, N-acetylmannosamine presumably exists largely as a negatively charged complex and is therefore excluded from the sulfonated polystyrene matrix, while N-acetylglucosamine occurs mainly as the free sugar in the equilibrium mixture and, being a neutral compound, has free access to the porous resin. The proposed mechanism for the separation was supported by the finding that glucose and glucose 6-phosphate could also be separated on a column of the same resin, with water as the eluent.

Acetylglucosamine↗
PubMed1993

Health behavior and outcomes in sequential pregnancies of black and white adolescents.

OBJECTIVE: To examine the relationships among parity, preterm delivery, fetal growth retardation, and prenatal care utilization in first and second adolescent pregnancies. DESIGN: A longitudinal, retrospective study in which obstetric, behavioral, and sociodemographic data were used to examine birth outcomes of 737 low-income black (80%) and white (20%) teenagers delivering first and second singleton infants at 20 or more weeks' gestation. SETTING: Public health clinics in Jefferson County, Alabama, between January 1983 and February 1990. MAIN OUTCOME MEASURES: Mean birth weight, preterm delivery, fetal growth retardation, Apgar scores, and perinatal mortality. MAIN RESULTS: In their second pregnancies, adolescents presented 2.8 weeks later for care (P = .0001) and made fewer total clinic visits. Mean infant birth weight increased by 91 g (P = .0005). This increase was significantly associated with an increase in maternal prepregnancy body mass index. The rate of fetal growth retardation decreased (P = .0001) and the rate of preterm delivery increased (P < .02) in the second pregnancy. The rate of recurrence of fetal growth retardation was 13% and the rate of preterm delivery was 46%. CONCLUSIONS: Poorer utilization of prenatal care and high risk for recurrence of adverse outcomes are characteristic of adolescents' second pregnancies and should be considered in teenage pregnancy intervention programs.

Adolescent↗
PubMed1993

Separation of N-acetylglucosamine and N-acetylmannosamine by chromatography on Sephadex in borate buffer.

Several procedures have been used previously for the separation of N-acetylglucosamine and N-acetylmannosamine, which are based on the difference in strength of the borate complexes of the two N-acetylhexosamines and include paper chromatography on borate-treated paper, paper electrophoresis in borate buffer, and anion-exchange chromatography of the borate complexes. In the present study, we have observed that the two sugars, despite their identical size in noncomplexed form, may also be separated by gel chromatography in borate buffer. Nearly complete resolution was obtained by chromatography on a column (1.5 x 117 cm) of Sephadex G-15, which was eluted at room temperature with 0.27 M sodium borate, pH 7.8 (prepared from H3BO3 by addition of NaOH), at a flow rate of 10 ml/h. This procedure complements existing methods for the separation of N-acetylmannosamine and N-acetylglucosamine and has the advantage that it can be carried out on a relatively large preparative scale.

Acetylglucosamine↗
PubMed1993

Developmental control elements in the promoter of a Drosophila vitelline membrane gene.

DNA fragments from the 5' flanking region of Drosophila melanogaster vitelline membrane gene VM26A1 were fused to hsp/lacZ reporter genes, reintroduced via P-element-mediated germ line transformation, and functionally assayed by histological staining for beta-galactosidase activity. A developmental control element capable of promoting the basic vitelline membrane (VM) expression pattern was found within a 176-bp region. Additional multiple genetic control elements were found to be involved in modifying the level and spatial pattern of reporter gene expression but these required the 176-bp element in order to function. Unexpectedly, in isolation this 176-bp core element also promotes abnormal expression of the reporter gene in border cells of stage 8 and 9 egg chambers. This abnormal border cell expression is apparently suppressed in the native gene by an adjacent negative control element.

Animals↗
PubMed1993

Noncovalent occupancy of the retinal-binding pocket of opsin diminishes bleaching adaptation of retinal cones.

Bright light bleaches visual pigment and leads to a persistent desensitization of isolated rod and cone photoreceptors called bleaching adaptation. Bleaching adaptation results from the combined effects of pigment depletion and adaptational modulation of certain cellular reactions in the visual transduction cascade. Here, we present evidence that in solitary cone photoreceptors isolated from the salamander retina, the latter effect is due to the presence of free opsin in the outer segment. Also, we demonstrate that this "opsin adaptation" can be reversed by treating the cells with synthetic retinoids similar to 11-cis retinal but having polyene chains too short to form protonated Schiff base attachments to opsin.

Adaptation, Physiological↗
PubMed1993

Application of Steffee operation in spinal surgery.

Steffee operation is a surgical method of internal fixation for unstable conditions of the spine. Up to March 1991, 32 cases of various spine disorders were treated with the Steffee system in our hospital. These operations brought good results, as 83.4% of the cases received either good or excellent functional and clinical ratings postoperatively. Among patients with spondylolisthesis, the degree of slip correction averaged 58.5% postoperatively. Neurological complications are avoided by accurate localization of the screws.

Adult↗