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Biomedical subjects

J Kong

Publications and source records attributed to J Kong.

At least 73 records · Page 4Linked to original sources
PubMed1998

Expression of the rat adrenomedullin receptor or a putative human adrenomedullin receptor does not correlate with adrenomedullin binding or functional response.

There has been considerable difficulty in defining distinct adrenomedullin (AM) binding sites and function in vivo. However, a rat adrenomedullin receptor (rAMR) and a putative human adrenomedullin receptor (hAMR) have recently been reported. We attempted to confirm and extend the pharmacological characterization of these cloned receptors. COS-7 cells transfected with rAMR or epitope tagged rAMR display abundant rAMR mRNA expression and cell-surface receptor localization. Specific 125I-AM binding is detected in transfected cells; however, similar levels of binding are also detected in cells transfected with vector DNA alone. This AM binding site fails to mediate any changes in cAMP in response to AM. In contrast, Swiss 3T3 cells, expressing specific endogenous AM receptors, display AM binding and functional cAMP responses. Transfection studies performed with the putative hAMR yield similar results. These data suggest that the proposed rAMR and hAMR do not represent authentic adrenomedullin receptors.

3T3 Cells↗
PubMed1998

Antagonistic roles of neurofilament subunits NF-H and NF-M against NF-L in shaping dendritic arborization in spinal motor neurons.

Dendrites play important roles in neuronal function. However, the cellular mechanism for the growth and maintenance of dendritic arborization is unclear. Neurofilaments (NFs), a major component of the neuronal cytoskeleton, are composed of three polypeptide subunits, NF-H, NF-M, and NF-L, and are abundant in large dendritic trees. By overexpressing each of the three NF subunits in transgenic mice, we altered subunit composition and found that increasing NF-H and/or NF-M inhibited dendritic arborization, whereas increasing NF-L alleviated this inhibition. Examination of cytoskeletal organization revealed that increasing NF-H and/or NF-M caused NF aggregation and dissociation of the NF network from the microtubule (MT) network. Increasing NF-H or NF-H together with NF-M further reduced NFs from dendrites. However, these changes were reversed by elevating the level of NF-L with either NF-H or NF-M. Thus, NF-L antagonizes NF-H and NF-M in organizing the NF network and maintaining a lower ratio of NF-H and NF-M to NF-L is critical for the growth of complex dendritic trees in motor neurons.

Animals↗
PubMed1998

Unrecognized microscopic hyphema masquerading as a closed head injury.

OBJECTIVE: To present a child with an unrecognized microscopic traumatic hyphema and acute glaucoma who was initially treated as a closed head injury patient. DESIGN: Case report and discussion. RESULTS: Symptoms attributable to unrecognized occult ocular injury in a child with sickle cell trait resulted in evaluation and treatment of the child for a closed head injury. Evaluation included a computed tomography scan of the head and lumbar puncture. An ophthalmologic consultation later revealed a microscopic hyphema and acute glaucoma as the etiology of the child's signs and symptoms. CONCLUSIONS: Children who present with neurologic symptoms and a history of ocular trauma should undergo an ophthalmologic examination as soon as possible. Hyphema, even if not readily visible on physical examination, can result in the development of acute glaucoma with signs and symptoms that resemble a closed head injury.

Child↗
PubMed1998

[Part of biological activity of peptidoglycan from Streptococcus lactis SB900].

Peptidoglycan of Streptococcus lactis SB900(LABPG) was isolated. It's chemical composition was analyzed and part of biological activity was examined. The PG contained 9.84% protein, 0.871 mumol/m NAG, 1.14 mumol/mg NAM. The amino acids of relatively high concentrations were Ala, Glu, Asp and their concentrations were 1.046, 0.775, 0.304 mumol/mg respectively. Using mice as subject, the animal experiment confirmed that LABPG was non-toxic and safe. Effect of i.p. LABPG 0.5 mg/mouse on the phagocytic function were studied. It was suggested that the phagocytic activity of PM phi had markedly enhanced, the activity of serum lysozyme was increased significantly. YC-Rosette experiment suggested that the activity of C3b receptors of PM phi were increased and the YC-Rosette forming ratio were higher than controls. The difference was significant by statistical analysis. Therefore, it is considered that LABPG was able to activate M phi and improve immune function in mice.

Animals↗
PubMed1997

Carcinogen-induced alteration in liver epidermal growth factor receptor distribution during the promotion stage of hepatocarcinogenesis in rat.

Changes in hepatic membrane binding capacity for epidermal growth factor (EGF) were assessed during 2-acetylaminofluorine (2-AAF)-induced hepatocarcinogenesis. An overall decrease in membrane EGF binding levels was observed throughout the period of 2-AAF administration. Immunochemical studies indicated the decreases in EGF binding levels were paralleled by decreases in tissue EGF receptor levels. Immunohistochemical studies showed that the losses in hepatic EGF receptor levels were not uniform throughout the liver during the early, promotion stage of cancer development. During the promotion stage, preneoplastic liver nodules were found to display a higher level of EGF receptor than surrounding hepatic tissue. This resistance to 2-AAF-mediated down-regulation of EGF receptor may confer a proliferative advantage to the developing nodule relative to the surrounding liver tissue. Similar immunochemical and immunohistochemical analysis of hepatocarcinomas at late stages of 2-AAF-induced hepatocarcinogenesis indicated a uniform loss of EGF receptor in tumor and surrounding tissue. These studies indicate that carcinogen-mediated changes in EGF binding levels are different during the multistage process of hepatocarcinogenesis, and that resistance to down-regulation of EGF receptor among preneoplastic nodules may have a role in providing a selective growth advantage to initiated cell populations. EGF receptor may be useful as a dynamic marker assessing the development of hepatic tumors.

2-Acetylaminofluorene↗
PubMed1997

Aryl sulfotransferase IV deficiency in rat liver carcinogenesis initiated with diethylnitrosamine and promoted with N-2-fluorenylacetamide or its C-9-oxidized metabolites.

Down regulation of aryl sulfotransferase IV (AST IV) in promotion/progression of liver carcinogenesis by N-2-fluorenylacetamide (2-FAA) has been established. This study examined whether the C-9 oxidized metabolites of 2-FAA, which have recently been shown to promote diethylnitrosamine (DEN)-initiated liver carcinogenesis in male Sprague-Dawley rats, effect the above change. Hence, in DEN-initiated rats, the effects of promoting regimens of 9-OH-2-FAA or 9-oxo-2-FAA, 15 oral doses at 50 and 100 mumol/kg of body weight, were compared to those of 2-FAA at 50 mumol/kg of body weight and of the vehicle on the activity of N-hydroxy(OH)-2-FAA sulfotransferase (ST), an isozyme of AST IV and AST IV expression and distribution. Relative to the vehicle, treatment with the fluorenyl compounds led to decreased levels in hepatic N-OH-2-FAA ST activity and development of hepatic nodules and tumors which had still lower levels of the ST activity than the respective remnant livers. At approximately 8 months after treatment with the C-9-oxidized compounds at doses twice that of 2-FAA, the extents of decreases in the hepatic N-OH-2-FAA ST activity and cytosolic AST IV protein in tumors were comparable to those with 2-FAA. Immunocytochemical analysis showed close association of AST IV deficiency with neoplastic liver lesions. In comparison to N-OH-2-FAA, 9-OH-2-FAA had only low and 9-oxo-2-FAA lacked sulfate acceptor activity in the presence of male rat liver cytosol or AST IV. At 3.3-fold greater concentration than N-OH-2-FAA, 9-oxo-2-FAA inhibited (27%) the sulfate acceptor activity of N-OH-2-FAA in the presence of AST IV, which suggested interference by 9-oxo-2-FAA at the active site. Although the C-9-oxidized compounds do not appear to be substrates for N-OH-2-FAA ST, their ability to cause a decrease in N-OH-2-FAA ST activity and protein similar to that of 2-FAA supports their role in hepatocarcinogenesis. Whereas 9-OH-2-FAA had a 3.9-fold greater sulfate acceptor activity in the presence of female than male rat liver cytosol and inhibited dehydroepiandrosterone ST activity of female rat liver, N-OH-2-FAA and 9-oxo-2-FAA inhibited estrone ST activity of male rat liver, suggesting that the C-9-oxidized compounds as well as N-OH-2-FAA are substrates for STs other than AST IV.

2-Acetylaminofluorene↗
PubMed1997

Strain differences in susceptibility to streptozotocin-induced diabetes: effects on hypertriglyceridemia and cardiomyopathy.

OBJECTIVE: Streptozotocin (STZ)-induced diabetes in Wistar rats results in severe hyperlipidemia and a characteristic cardiomyopathy. However, Wistar-Kyoto (WKY) rats made diabetic with a similar dose of STZ did not develop heart dysfunction or hypertriglyceridemia at 12 weeks post-STZ. We investigated whether an apparent resistance of the WKY strain to develop diabetic cardiomyopathy and hypertriglyceridemia following chronic diabetes could be due to a reduced susceptibility to the diabetogenic effects of STZ. METHODS: Adult male WKY and Wistar rats were made diabetic with a moderate (55 mg/kg) or high (75 mg/kg) dose of STZ. At 6 weeks of diabetes, glucose tolerance, cardiac function, pancreatic insulin content and basal and post-heparin plasma lipolytic activity were determined. RESULTS: Administration of a moderate dose of STZ produced cardiac dysfunction in Wistar but not WKY rats at 6 weeks after diabetes induction. The same dose of STZ in WKY rats also resulted in a lesser degree of hyperglycemia and glucose intolerance, and significantly higher pancreatic insulin content relative to Wistar rats. Following a high dose of STZ, the apparent resistance to developing cardiomyopathy was lost in the WKY rats. As well, the WKY rats demonstrated an equal degree of hyperglycemia and glucose intolerance as Wistar rats. However, unlike the Wistar strain, WKY rats did not demonstrate either hypertriglyceridemia or a reduced heparin-releasable plasma lipoprotein lipase (LPL) activity following a high dose of STZ. CONCLUSIONS: These results suggest that the incidence of diabetes-related cardiomyopathy and hypertriglyceridemia in rats may be independently influenced by strain-dependent susceptibilities to the beta-cytotoxic effects of STZ. The absence of hypertriglyceridemia in severely diabetic WKY rats may be linked to the maintenance of a critical level of plasma LPL activity.

Animals↗
PubMed1997

Access to bone marrow transplantation for leukemia and lymphoma: the role of sociodemographic factors.

PURPOSE: Use of bone marrow transplantation (BMT), a complex, costly treatment for many forms of cancers, has increased significantly in recent years. The increasingly competitive health care marketplace raises concerns about patient access to costly medical procedures such as BMT. We attempted to evaluate patient access to BMT for the treatment of leukemias and lymphomas. METHODS: We analyzed inpatient hospital discharge data from four states (California, Maryland, Massachusetts, and New York) for 2 years (1988 and 1991) to examine whether the use of BMT for patients with either leukemia or lymphoma varies by sociodemographic characteristics and insurance coverage. We developed a sorting algorithm to collapse the discharge data into patient level records. We used logistic regression to analyze the odds of receiving a BMT stratified by disease type (leukemia or lymphoma). RESULTS: After controlling for other factors, black patients with leukemia are 51% to 53% as likely as whites, while black patients with lymphoma are 34% to 45% as likely as white patients to undergo a BMT (P < .05). Medicaid, self-pay patients, and Health Maintenance Organization (HMO) enrollees with either leukemia or lymphoma are significantly less likely to undergo a BMT compared with patients with private insurance. Younger patients are significantly more predisposed to undergo a BMT than older patients. The odds of receiving a BMT have increased over time, but the rates of increase vary by state. Consistent with clinical expectations, the relative odds of BMT vary significantly by type of leukemia or lymphoma. CONCLUSION: Substantial variation exists in access to BMT for patients with either leukemia or lymphoma. Black patients, those enrolled in HMOs, those covered by Medicaid, and self-pay patients were less likely to receive a BMT when admitted for either leukemia or lymphoma. These findings raise concerns about access to cancer treatments for patients in the current health care system.

Black or African American↗
PubMed1997

[Isolation of 28 new STSs at Xq27.3].

A plasmid sublibrary of the 475 kb insert of YAC209G4 was constructed by using pBS II KS vector. The library of 3,500 clones having 100-600 bp inserts was screened with the probe of the 475 kb insert blocked with competitor DNA. Sixty unique single copy clones were found and sequenced. Checking with GenBank, 28 new STSs were obtained. Genbank accession numbers are U26560-26587. Three STSs were tested by PCR with appropriate primers using human genomic DNA as template and showed specific amplification bands as expected.

Chromosome Fragility↗
PubMed1997

[Ethnopharmacology of Phyllanthus emblica L].

This paper deals with the ethnopharmacology of P. emblica, a traditional herbal medicine used by many peoples in the world. The paper introduces the biological characters, geographical distribution-patterns, chemical constitution and pharmacology of the plant. By cross-cultural comparative study, this paper indicates that there are 17 countries and nations of the world using various parts of P. emblica in their medical treatment. The medicinal plant is good for anti-hepatitis, anti-cancer, anti-tumor and regulation of stomachal function. The plant is also regarded as a traditional immunomodulator and a natural adaptogen. The result of the study reveals that P. emblica is an important traditional medicine with broad prospects.

Animals↗
PubMed1996

Quantitative analysis of changes in cell proliferation and apoptosis during preneoplastic and neoplastic stages of hepatocarcinogenesis in rat.

In situ markers for quantitative analysis of cell proliferation and apoptotic cell death have been used to evaluate both the proliferation level and net growth potential of preneoplastic nodules and malignant tumor tissues from rats experimentally induced for hepatocarcinogenesis by the dietary administration of 2-acetylaminofluorene. The findings show that although tumors have a much higher level of cell proliferation than preneoplastic liver nodules, the nodules have a higher potential for net growth when apoptosis is taken into account. These results support a role for a decrease in apoptosis during the promotion stage of carcinogenesis.

2-Acetylaminofluorene↗
PubMed1996

Results of the economic evaluation of the first study. A multinational prospective economic evaluation. FIRST Investigators. Flolan International Randomized Survival Trial.

We present the prospective economic evaluation that served as a secondary endpoint for the FIRST study, a randomized international multicenter trial of patients with severe congestive heart failure. Although the clinical results of this study were disappointing, we demonstrated the feasibility of incorporating prospective economic evaluation in phase III clinical trials.

Aged↗
PubMed1996

Thrombolytic therapy with tissue plasminogen activator for prevention of vasospasm in experimental subarachnoid hemorrhage: its efficacy and problems.

We investigated the efficacy of two different tissue plasminogen activators (t-PA) for preventing vasospasm after experimental subarachnoid hemorrhage (SAH) in rabbits. Intrathecal injection of Silteplase and Alteplase showed significant preventive action against vasospasm following SAH and thrombolytic effect. The low dose groups with both t-PA showed more preventive action on day 1 than the high dose groups. The data suggest that the determination of optimum dose of t-PA is essential in clinical use of t-PA.

Animals↗
PubMed1996

[Comparison between the plaque reduction neutralization test and the hemagglutination inhibition test in determination of human anti-measles antibodies].

In order to evaluate the difference between plaque reduction neutralization test (PNt) and hemagglutination inhibition (HI) test on human anti-measles antibodies, pre- and postimmunization sera collected from 328 infants aged 3-6 months who were immunized with Shanghai 191 measles vaccine, were detected by both methods. The results demonstrated that PNt was more sensitive than HI when they were used to measure the pre-immunization sera. No significant difference was found between these two methods when they were used to measure the post-immunization sera. PNt can be used to test low level maternal anti-measles antibodies in infants, especially for estimating the effect of maternal anti-measles antibodies on the immunogenicity of measles vaccine.

Antibodies, Viral↗
PubMed1996

[Construction of Chinese genomic cosmid library].

A Chinese genomic library has been constructed using SuperCos1 cosmid vector. 6.09 x 10(5) clones were obtained with an everage insert size of 40 kb ranging from 32 to 45 kb, which cover approximately 8.12 fold human genomic DNA. DNA pools prepared from the total library were screened with 6 known markers distributed on different chromosomes, which all were tested positive.

Asian People↗
PubMed1995

Effect of dietary restriction on partial hepatectomy-induced liver regeneration of aged F344 rats.

Fourteen weeks-old male F344 rats maintained on a reduced caloric diet (60% of ad libitum (AL) food consumption) for 6 weeks or for 14 months did not affect the hepatic cell proliferation in terms of % S phase population, determined by evaluation of DNA synthesis in hepatocytes isolated from either young (5 months) or aged (18 months) rats. However, hepatic basal cellular DNA synthesis estimated by [3H]thymidine incorporation was reduced through acute dietary restriction (DR) in young rats, but increased in aged animals after 14 months restriction. Partial hepatectomy (PH) on aged rats stimulated hepatocyte regeneration and restored some aging-associated biochemical functions, such as drug metabolizing enzyme-dependent xenobiotic metabolic activation which was determined by measuring the formation of carcinogen-DNA adducts. Forty-eight hours after partial hepatectomy, the % of S phase population and the basal nuclear DNA synthesis of hepatocytes isolated from the partial hepatectomized DR-rats were 4- and 2.8-fold, respectively, greater than those of hepatocytes from AL-animals. DR reduced aflatoxin B1 (AFB1) metabolizing enzyme activity and decreased the AFB1-DNA adduct formation in young rats treated with AFB1. In aged AL-rats, the formation of AFB1-DNA adducts diminished to the same level as that of DR-groups and probably was due to the faster decline of drug metabolizing enzymes in aging AL-rats. However, 48 h after PH, the metabolic activation of AFB1 was restored in AL- and DR-groups which resulted in the increase of AFB1-DNA binding by 4.2 and 1.9-fold, respectively. During the liver regeneration of old PH-rats, DR inhibited the AFB1-DNA adduct formation after the PH-rats received a single dose of AFB1. DR increased benzo[a]pyrene (BaP) metabolic activation in both young and aged rats. Aging also decreased BaP-DNA adduct formation in both DR and AL-rats. The increase of BaP-DNA adduct formation in PH-groups was attributed to the restoration of BaP-metabolizing enzyme activity during liver regeneration. The PH-stimulated BaP-DNA adduct formation in AL- and DR-rats was 3.4- and 2.0-fold greater than control aged rats. Our results indicated that the stimulation of PH-induced liver regeneration by DR in aged animals may be attributed to the retardation of aging by DR and the retention of more active biochemical and enzymological functions in old DR-animals.

Aflatoxin B1↗
PubMed1995

Scanning microfluorometric analysis of proliferating cell nuclear antigen in formalin-fixed sections of hyperplastic and neoplastic rat liver.

Scanning laser cytometric analysis of fluorochrome-labeled cells was used to survey and quantitate the distribution of proliferating cells in formalin-fixed, paraffin-embedded tissue sections from hyperplastic and neoplastic rat livers. The technique used fluorescent immunochemical staining of proliferating cell nuclear antigen (PCNA) as a marker for proliferating cells and propidium iodide as a fluorescent nuclear counterstain. Use of an antigen retrieval treatment improved detection of PCNA and treatment of tissue sections with crystal violet improved the sensitivity of the method by quenching background autofluorescence. PCNA evaluation of cell proliferation in regenerating rat liver 0-48 h post-partial hepatectomy showed that 3-43% of cells stained positively for PCNA, a pattern closely correlating with previously reported rates of maximum DNA synthesis. The PCNA staining patterns observed among cells in neoplastic nodules were more focal in distribution and indicated that from 5 to 25% of the cell nuclei per nodular region stained positively for PCNA. This use of image analysis for the rapid identification of proliferating cell areas in fixed, paraffin-embedded tissue active in neoplastic growth will expedite in situ cytochemical and molecular studies attempting to identify key differences between hyperplastic and neoplastic growth.

Animals↗