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Biomedical subjects

H Ji

Publications and source records attributed to H Ji.

176 records · Page 10Linked to original sources
PubMed1989

Metabolism of inositol pentakisphosphate to inositol hexakisphosphate in Xenopus laevis oocytes.

The formation and metabolism of inositol pentakis-and hexakisphosphates (InsP5 and InsP6) were investigated in Xenopus laevis oocytes. After [3H]inositol injection, [3H]InsP5 and subsequently [3H]Insp6 increased progressively over 72 h. In intact oocytes, [3H]InsP5 was progressively converted to [3H]InsP6 from 6 to 72 h of incubation and was not metabolized to lower inositol phosphates. In contrast, [3H]InsP6 remained unmetabolized for up to 72 h. These data are consistent with the kinetics of the increases in [3H]InsP5 and [3H]InsP6 in [3H]inositol-labeled oocytes. The highly phosphorylated inositols showed significant changes during oogenesis and maturation. In oocytes incubated for 48 h after [3H]inositol injection, the radioactive incorporation into polyphosphoinositols increased progressively from stage 3 to stage 6, with 5- and 6-fold rises (cpm/mg protein) for [3H]InsP5 and [3H]InsP6, respectively. These developmental changes were associated with 5-fold increases in [3H]inositol tetrakisphosphate between stages 3 and 6 of oogenesis. Induction of oocyte maturation by progesterone (1 microM) during the last 12 of a 36-h incubation with [3H]inositol doubled the levels of [3H]InsP6 relative to [3H]InsP5, suggesting that the activity of inositol pentakisphosphate kinase increases during maturation. These results provide direct evidence for metabolic conversion of InsP5 to InsP6 in animal cells and show that the higher inositol polyphosphates, unlike the lower phosphoinositols, are extraordinarily stable. These species increase markedly during ovum development and may play a regulatory role in oogenesis and maturation.

Animals↗
PubMed1989

[Luteal function in patients with endometriosis].

UNLABELLED: Luteal function was studied in 19 cases with endometriosis, infertility being present in 16 cases. Based on previous menstrual cycles, BBT graphs and cervical mucus scores, serum LH concentrations were measured consecutively for 3 days during peri-ovulatory period to define day of LH peak (D0). Meanwhile, serum estradiol (E2) and progesterone (P) levels were determined in early, mid and late luteal phase. Endometrium biopsies were done on 4th and 12th days after BBT rise in 16 cases and dated according to Noyes' criteria. Six normally cycling women with matched age were served as controls. RESULTS: Serum LH peaks were detected in all patients and normal subjects. All data were synchronized by D0, and analyzed. In endometriosis group, mean serum P levels in early, mid-luteal phase and total luteal phase (the sum of 3 values) were significantly lower than those in control group. Five cases (26.3%) showed low P levels during mid-luteal and/or total luteal phase. Delayed endometrial maturation was observed in 10 of 16 cases (62.5%). Short luteal phase and/or delayed elevation of BBT were shown in 3 of 14 cases (21.4%). Besides, 10 of 12 cases (83.3%) had at least one abnormality in all 3 parameters and 7 cases (58.3%) had two abnormalities. In conclusion, the incidence of luteal phase defect (LPD) is higher in endometriosis group than that in the controls. The mechanisms of LPD and its relationship with infertility were discussed.

Adult↗
PubMed1989

[Clinical, immunophenotypic and cell cyclic analysis in chronic lymphocytic leukemia].

15 cases of chronic lymphocytic leukemia (CLL) were immunophenotyped with a panel of monoclonal antibodies. 13 cases were B-CLL, which was characterized by CD20+, HLA-Dr+, SmIg+ and CD5+/Em+. 2 cases were T-CLL, one with Ts phenotype and HLA-Dr+ T-Cll in the other. The ratio of G0 + G1 cells in bone marrow of CLL was 91.1 +/- 2.3% (76.0 +/- 5.1% in controls), while S + G2M cells was 8.9 +/- 2.3% (23.9 +/- 5.1% in controls). The ratios of various cyclic cells were similar in bone marrow and in peripheral blood. Prolymphocytoid transformation developed in the late stage in 3 CLL patients. The clinical course, cytochemistry and immunologic changes in CLL were also analysed.

Aged↗
PubMed1989

Luteal function in patients with endometriosis.

Nineteen patients with endometriosis were selected for investigation of luteal function as determined by serum progesterone (P) concentrations at different stages of the luteal phase, and by observation of basal body temperature (BBT) profiles and endometrial histological appearances. Sixteen cases were accompanied with infertility. All data were synchronized to the day of midcycle serum luteinizing hormone (LH) peak (D0) and analyzed accordingly. In the endometriosis group, mean serum P concentrations of early, mid luteal phases and the integrated P concentration of the whole luteal phase were significantly lower than in the control group. Five cases (26.3%) had low peak P values during mid-luteal phase and/or low integrated P levels. Delayed endometrial maturation was revealed in 10 of 16 cases (62.5%). Short luteal phase, as defined by BBT, was observed in 3 of 14 cases (21.4%). A total of 12 cases were screened for all three parameters, among them, ten (83.3%) had at least one abnormality and seven (58.3%) showed two aberrant results. In summary, the incidence of luteal phase defect was higher in the endometriosis group than in controls. The pathogenic mechanism of luteal phase defect and its role in infertility are discussed.

Adult↗
PubMedDate not supplied

Two-dimensional electrophoretic analysis of proteins expressed by normal and cancerous human crypts: application of mass spectrometry to peptide-mass fingerprinting.

Protein patterns of normal human colonic crypts, isolated from different regions of the large intestine, and several colorectal cancer cell lines were compared using two-dimensional electrophoresis gels (2-DE). As detected by intrinsic radiolabeling and Coomassie Brilliant Blue staining, the protein patterns for normal crypts isolated from the ascending, and descending, regions of the colon and the rectum, were almost (> 95%) identical. While 75-80% of the protein spots from normal crypts and the colorectal cancer cell line (LIM 1863), a cell line that grows as organoids and differentiates spontaneously into crypt-like structures in vitro, can be matched, the relative expression levels of a large number of proteins differ. At least two protein spots (undetectable in the protein pattern from normal cells), proteins a (M(r) approximately 18,000, pI 6.7-6.9) and b (M(r) approximately 24,000, pI 5.9-6.0), were detected in the 2-DE gel protein pattern in the three cell lines LIM 1863, LIM 1215 and LIM 1899. The identity of these proteins is not yet known and further studies are required before they can be considered as potential colon tumor markers. Approximately 60% of the cellular proteins from LIM 1215 cells, a colon carcinoma cell line that exhibits many properties associated with columnar cells, can be matched with LIM 1863 cells. The results presented here represent an initial phase in our efforts to develop a comprehensive protein database for normal human colon cells and several colorectal cancer cell lines. While our initial protein identification relied on microsequencing methodologies, we are presently evaluating peptide-mass fingerprinting, utilizing capillary reversed-phase high-performance liquid chromatography (RP-HPLC) and electrospray mass spectrometry, as a means for rapid identification of proteins at subpicomole levels. Using this approach, protein #3 (M(r) approximately 66,000, pI 6.2) was identified as heat shock protein 60 from as few as seven tryptic peptide masses when they were screened against the molecular weight search (MOWSE) peptide-mass database.

Amino Acid Sequence↗
PubMedDate not supplied

Two-dimensional electrophoretic analysis of human breast carcinoma proteins: mapping of proteins that bind to the SH3 domain of mixed lineage kinase MLK2.

MLK2, a member of the mixed lineage kinase (MLK) family of protein kinases, first reported by Dorow et al. (Eur. J. Biochem. 1993, 213, 701-710), comprises several distinct structural domains including an src homology-3 (SH3) domain, a kinase catalytic domain, a unique domain containing two leucine zipper motifs, a polybasic sequence, and a cdc42/rac interactive binding motif. Each of these domains has been shown in other systems to be associated with a specific type of protein interaction in the regulation of cellular signal transduction. To study the role of MLK2 in recruiting specific substrates, we constructed a recombinant cDNA encoding the N-terminal 100 amino acids of MLK2 (MLK2N), including the SH3 domain (residues 23-77), fused to glutathione S-transferase. This fusion protein was expressed in Escherichia coli, purified using gluthathione-Sepharose affinity chromatography and employed in an affinity approach to isolate MLK2-SH3 domain binding proteins from lysates of 35S-labelled MDA-MB231 human breast tumour cells. Electrophoretic analysis of bound proteins revealed that two low-abundance proteins with a molecular weights (Mr) of approximately 31,500 and approximately 34,000, bound consistently to the MLK2N protein. To establish accurately the Mt / isoelectric point (pI) loci of these MLK2-SH3 domain binding proteins, a number of abundant proteins in a two-dimensional electrophoresis (2-DE) master gel were identified to serve as triangulation marker points. Proteins were identified by (i) direct Edman degradation following electroblotting onto polyvinylidene difluoride (PVDF) membranes, (ii) Edman degradation of peptides generated by in-gel proteolysis and fractionation by rapid (approximately 12 min) microbore column (2.1 mm ID) reversed-phase high performance liquid chromatography (HPLC), (iii) mass spectrometric methods including peptide-mass fingerprinting and electrospray (ESI)-mass spectrometry (MS)-MS utilizing capillary (0.2-0.3 mm ID) column chromatography, or (iv) immunoblot analysis. Using this information, a preliminary 2-DE protein database for the human breast carcinoma cell line MDA-MB231, comprising 21 identified proteins, has been constructed and can be accessed via the World Wide Web (URL address: http:(/)/ www.ludwig.edu.au/www/jpsl/jpslhome.htm l).

Amino Acid Sequence↗
PubMedDate not supplied

A two-dimensional gel database of human colon carcinoma proteins.

The master two-dimensional gel database of human colon carcinoma cells currently lists cellular proteins from normal crypts and the colorectal cancer cell lines LIM 1863, LIM 1215 and LIM 1899 (Ward et al., Electrophoresis 1990, 11, 883-891; Ji et al., Electrophoresis 1994, 15, 391-405). Updated two-dimensional electrophoretic (2-DE) maps of cellular proteins from LIM 1215 cells, acquired under both nonreducing and reducing conditions, are presented. Fifteen cellular proteins are identified in the reducing 2-DE gel map, and seven in the nonreducing gel map, along with a tabular listing of their M(r)/pI loci and mode of identification. We also include our mass spectrometric based procedures for identifying 2-DE resolved proteins. This procedure relies on a combination of capillary column (0.10-0.32 mm internal diameter) reversed-phase HPLC peptide mapping of in-gel digested proteins, peptide mass fingerprinting, sequence analysis by either collision-induced dissociation or post-source-decay fragmentation, and protein identification using available database search algorithms. These data, and descriptions of the micro-techniques employed in this laboratory for identifying 2-DE resolved proteins can be accessed via the internet URL: http:(/)/www.ludwig.edu.au.

Amino Acid Sequence↗
PubMedDate not supplied

Electrophoretic analysis of the novel antigen for the gastrointestinal-specific monoclonal antibody, A33.

The murine monoclonal antibody A33 (mAbA33) recognises a human cell membrane-associated antigen selectively expressed in epithelial cells of the lower gastrointestinal tract and > 90% of colonic cancers, but is not detected in a wide range of other normal tissues by immunohistochemical analysis. In phase I/II clinical triasl, mAbA33 has been shown to target advanced colon cancers and the humanized version is currently being evaluated in therapy studies. Although the mAbA33 has been well characterised by immunohistochemical and clinical studies, until recently, the target antigen has remained poorly defined. This was largely attributable to the antigenic determinant recognised by mAbA33 being dependent on the native spatial conformation of the A33 antigen which impeded its identification by conventional two-dimensional electrophoresis (2-DE) and immunoblot analysis. We have developed an immunoblot method, based on nonreducing/non-urea precast 2-DE gels, that has facilitated the purification of the detergent (0.3% Triton X-100) solubilised A33 antigen from the human colon cancer cell lines LIM1215 and SW1222. Under these 2-DE conditions, the A33 antigen electrophoreses with an apparent M(r) approximately 41000 and pI 5.0-6.0. Attempts to isolate the A33 antigen from 2-DE gels for direct structural analysis were unsuccessful, due to its co-electrophoresis with actin and cytokeratin proteins. However, using Western blot and biosensor detection the A33 antigen has been purified chromatographically and N-terminal sequence analysis was possible. Using polyclonal antibodies raised against a synthetic peptide corresponding to the N-terminal region of the A33 antigen we have used Western blot analysis to localise the molecule in our master 2-DE protein database for normal human colon crypts and several colon carcinoma cell lines (URL address: http:(/)/www.ludwig.edu.au). Under reducing 2-DE conditions, the A33 antigen electrophoresis as 6 differentially charged isoforms (pI 4.6-4.8) with a single molecular weight species at M(r) approximately 55000.

3T3 Cells↗
PubMedDate not supplied

Focal eosinophilic infiltration of the liver: a mimick of hepatic metastasis.

We present three cases of focal eosinophilic infiltration in the liver that mimicked hepatic malignancy on computed tomography during hepatic arteriography (CTHA) and computed tomography during arterial portography (CTAP). In all patients, focal eosinophilic liver infiltration appeared as a solitary nodule or as two nodules without hepatosplenomegaly and showed homogeneous hyperattenuation on CTHA and hypoattenuation on CTAP.

Diagnosis, Differential↗
PubMedDate not supplied

Compensatory hyperphagia after fasting tracks recovery of liver energy status.

Studies using metabolic inhibitors suggest that a reduction in hepatic ATP generates a stimulus that triggers feeding behavior. To investigate the relationship between changes in liver ATP and food intake under physiological conditions, we assessed changes in feeding behavior and liver adenine nucleotides during refeeding after 24 h of food deprivation. Deprived rats consumed 14 g of food in the first 3 h of refeeding; the rate of consumption declined markedly thereafter for the next 9 h, but remained higher than that seen in nonfasted rats. Fasting produced substantial reductions in ATP, ATP/ADP, and phosphorylation potential relative to fed levels. Refeeding restored liver ATP by 6 h, whereas ATP/ADP and phosphorylation potential did not fully recover until 12 h of refeeding. Restricting food intake during refeeding limited recovery of liver energy status. These results show that liver energy production recovers slowly during refeeding with a time course that parallels the compensatory change in eating behavior. These findings raise the possibility that changes in hepatic energy status play a role in satiation as well as in hunger.

Adenosine Diphosphate↗
PubMedDate not supplied

Nitric oxide induces oxidative damage in addition to deamination in macrophage DNA.

Inflammatory cells such as phagocytes, neutrophils, and macrophages have been implicated in the pathogenesis of several forms of clinical and experimental tumor development. It is hypothesized that this process is mediated by the production of reactive species including NO., O2.-, H2O2, and ONOO- which inflict DNA damage. In this study, the role of NO. in combination with oxygen radicals in DNA damage was investigated. DNA deamination (xanthine) and oxidation [5-(hydroxymethyl)uracil (5HMU), 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FAPY-G), and 8-oxoguanine (8oxoG)] products were identified in the DNA of macrophages (RAW264.7) activated with Escherichia coli lipopolysaccharide (LPS) and mouse gamma-interferon (INF-gamma). The formation of these products was inhibited by N-methyl-L-arginine (NMA), a nitric oxide synthase inhibitor. NMA inhibited only the production of nitric oxide and had no effect on superoxide production. These results demonstrate that NO. plays a dual role in damaging the DNA of activated macrophages. Autoxidation of NO. leads to nitrosating species which cause deamination of bases. Reaction of NO. with O2.- leads to DNA oxidative damage due to the formation of peroxynitrite which may have HO.-like oxidizing potential. Another possible mechanism of oxidative damage by NO. could be the mobilization of free iron by NO. which could ultimately cause Fenton-type reactions. Therefore, nitric oxide not only leads to deamination of DNA bases but is also an obligatory factor in oxidative damage to DNA.

Animals↗
PubMedDate not supplied

Structure of lasiansine from Aconitumnagarum var. lasiandrum.

A new C19-diterpenoid alkaloid, lasiansine (1), was isolated from the roots of Aconitu nagarum var. lasiandrum (Ranunculaceae) together with six known diterpenoid alkaloids. The structure of 1 was elucidated by spectral methods (1H-NMR, 13C-NMR, 2D-NMR, HRMS, IR), and the 13C-NMR spectrum of 16-epipyroaconine (3) and the single-crystal X-ray analysis of its derivative (5) are reported for the first time.

Aconitum↗
PubMedDate not supplied

Urinary excretion of 2-amino-3,8-dimethylimidazo-[4,5-f]quinoxaline in white, black, and Asian men in Los Angeles County.

The heterocyclic aromatic amines produced by high temperature cooking of foods containing creatin(in)e and amino acids (such as beef, pork, poultry and fish) are a class of potent animal carcinogens and have been implicated indirectly in human colon and pancreas carcinogenesis. We studied the urinary excretion of a mutagenic heterocyclic aromatic amine compound, 2-amino-3,8-dimethylimidazo-[4,5-f]quinoxaline (MelQx), among 47 black, 41 Asian (Chinese or Japanese), and 43 non-Hispanic white (white) male residents of Los Angeles County by quantitative analysis of total free and conjugated MelQx in pooled overnight urine collections. Significant interracial differences were observed. Geometric mean level in blacks was 1.3- and 3.0-fold higher than that in Asians and whites, respectively. Urinary level of MelQx was positively associated with intake frequencies of bacon, pork/ham and sausage/luncheon meats among study subjects, consistent with the observation that in Los Angeles, blacks had the highest consumption of these three food groups among the three races. Among men in Los Angeles County, the incidence rates of pancreas and colon cancers, which have been shown to be positively related to intake of fried meats, are 50% and 20% higher in blacks relative to Asians and whites, respectively. Our results are, therefore, consistent with the hypothesis that exposure to heterocyclic aromatic amines is related to risk of pancreas and colon cancers, and may in part explain the higher incidence among blacks relative to Asians and whites in Los Angeles.

Adult↗