Biomedical subjects
Publications and source records attributed to J Pan.
Five flavonoids were isolated from Epimedium wanshanense and identified as sagittatoside B, anhydroicaritin-3-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-rhamnopyranoside, sagittatoside A, ikarisoside B and desmethylanhydroicaritin-3-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L- rhamnopyranoside by means of IR, UV, 1HNMR, 13CNMR, MS and chemical evidence. They were obtained from this plant for the first time.
P-selectin, an adhesion receptor for leukocytes, is constitutively expressed by megakaryocytes and endothelial cells. Synthesis of P-selectin is also increased by some inflammatory mediators. We characterized a previously identified kappa B site (-218GGGGGTGACCCC-207) in the promoter of the human P-selectin gene. The kappa B site was unique in that it bound constitutive nuclear protein complexes containing p50 or p52, but not inducible nuclear protein complexes containing p65. Furthermore, the element bound recombinant p50 or p52 homodimers, but not p65 homodimers. Methylation interference analysis indicated that p50 or p52 homodimers contacted the guanines at positions -218 to -214 on the coding strand and at -210 to -207 on the noncoding strand. Changes in the three central residues at -213 to -211 altered binding specificity for members of the NF-kappa B/Rel family. Mutations that eliminated binding to NF-kappa B/Rel proteins reduced by approximately 40% the expression of a reporter gene driven by the P-selectin promoter in transfected bovine aortic endothelial cells. Overexpression of p52 enhanced P-selectin promoter activity, and co-overexpression of Bcl-3 further induced promoter activity in a kappa B site-dependent manner. In contrast, overexpression of p50 repressed promoter activity; this repression was prevented by co-overexpression of Bcl-3. Similar phenomena were observed with reporter gene constructs driven by two tandem P-selectin kappa B sequences linked to the SV40 minimal promoter. These data suggest that Bcl-3 differentially regulates the effects of p50 and p52 homodimers bound to the kappa B site of the P-selectin promoter. This site may be a prototype for kappa B elements in other genes that bind specifically to p50 and/or p52 homodimers.
The keratins are a component of the cytoskeleton that is present in fetal and neonatal rat granulosa cells (ROG), but disappears as the cells undergo postnatal steroidogenic differentiation. Steroidogenesis is initiated in the fetus as a low level constitutive function which is cAMP responsive, but becomes responsive to gonadotrophic hormones only after birth. ROG from PMSG-primed immature rats, like mature ROG, are keratin negative, highly steroidogenic and gonadotrophin-responsive, but rapidly lose their steroidogenic capacity in culture. In such cultured cells, transformation with the Kirsten-ras oncogene (v-Ki-ras) maintains low levels of constitutive steroidogenesis and responsiveness to cAMP, and induces the expression of keratin. To determine whether similar changes would occur in cells expressing both the SV40 and v-Ki-ras, cultured ROG were transformed with SV40 early genes, with Kirsten murine sarcoma virus (KiMSV), or with both agents concurrently. Keratin was demonstrated by fluorescence microscopy and Western blots, and progesterone production by RIA. ROG transformed with SV40 alone became immortalized but secreted little steroid and lacked keratin. In contrast, three cell lines, co-transformed with SV40 plus KiMSV, acquired keratin as well as the capacity to secrete progesterone in response to cAMP, closely resembling cells transformed with Ki-ras alone. KiMSV-transformed muscle fascia fibroblasts lacked both steroidogenic potential and keratin. The results show that the complex, v-Ki-ras-induced changes in steroidogenesis and keratin expression are reproducible and tissue specific. The phenotypic resemblance between singly and doubly transformed ROG indicates that the v-Ki-ras oncogene does not act by overcoming SV40-mediated inhibition of differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)
We report here on the characterization of soluble and particulate forms of the inducible nitric oxide synthase in RAW 264.7 macrophage cells. Stimulation of these cells with E. coli lipopolysaccharide and interferon-gamma resulted in a significant induction of nitric oxide synthase activity with approximately 20% of the total activity localized to the cell membrane. Like the soluble enzyme form, the membrane-associated nitric oxide synthase activity was inhibited by NG-monomethyl-L-arginine and did not require the addition of calcium. Both protein forms were immunoreactive on Western blots with antibodies specifically recognizing the carboxyl terminus of the protein. In contrast, antibodies specific for the amino terminus recognized inducible nitric oxide synthase from the cytosol, but failed to recognize the membrane-associated protein. Thus, macrophage cells are capable of expressing two forms of the inducible nitric oxide synthase that are definable by an intracellular distribution that correlates to antigenic differences at the amino terminus.
We performed proton magnetic resonance spectroscopic imaging (MRSI) at high magnetic field (4.1 T) to study N-acetylaspartate, creatine, and choline levels in the brains of normal control subjects and patients with intractable temporal lobe epilepsy. We compared the results of MRSI to those of other presurgical techniques to determine the sensitivity of this method in the lateralization of the epileptic focus. The normal hippocampal creatine-N-acetylaspartate ratio was 0.71 +/- 0.14 with no differences between left and right. Using the mean control hippocampal creatine-N-acetylaspartate ratio plus 2 standard deviations to identify statistically significant changes, we found lateralizing metabolic abnormalities corresponding to the operated temporal lobe in all patients. Four patients (40%) had contralateral abnormalities, and 2 of them had bilateral independent seizure onset confirmed by intracranial electroencephalographic studies. Statistically significant increases in the choline-N-acetylaspartate ratio in comparison to healthy volunteers were observed in 8 of the 10 patients. With the creatine-N-acetylaspartate ratio, MRSI demonstrated a 100% sensitivity compared to magnetic resonance imaging, which identified pathology in 70% of the patients. These findings suggest that proton MRSI yields a distinctive metabolic profile in patients with temporal lobe epilepsy and is sensitive in detecting bilateral metabolic abnormalities in some patients. These preliminary findings suggest that MRSI is more sensitive than magnetic resonance imaging in the lateralization of epileptic foci in temporal lobe epilepsy.
Glimepiride is an oral sulfonylurea drug; nicotinamide is an inhibitor of poly (ADP-ribose) synthetase and a precursor of NAD. Three studies were carried out to determine whether glimepiride and/or nicotinamide could prevent diabetes in BB rats. In Study I, we administered glimepiride treatment 200 mg/kg/day orally from the 35th to 143rd day of age. The incidence of diabetes in the glimepiride group was lower than in the control group (32% vs 55%, p < 0.02). In Study II, the treatment period was from the 35th to 147th day of age, and rats received glimepiride combined with nicotinamide (500 mg/kg/day IP). The treatment group showed a 22% incidence of diabetes compared to 53 in controls (p < 0.03). In Study III, nicotinamide treatment alone (1000 mg/kg/day orally) and combined with glimepiride were compared to untreated controls. The treatment period was from the 35th to 167th day of age. Nicotinamide-treated rats showed a 42% incidence of diabetes compared to 60% in controls (p = NS). In the nicotinamide combined with glimepiride treatment group, a lower incidence (28%) was observed when compared to the controls (60%, p < 0.05). These findings suggest that glimepiride can prevent diabetes in BB rats; however, nicotinamide when used in young animals shows only a trend to lower the incidence of diabetes, and when combined with glimepiride, no significant effect is observed.
Transformation with ras oncogenes causes loss, maintenance or modulation of differentiation, depending on the developmental history of the target cells. In the present study, we examined steps in signal transduction that may underlie some of this variation, using steroidogenic cells of adult rats as the model system. Steroidogenesis in normal cells is regulated by cyclic AMP and protein kinase A (the cAMP/PKA pathway). We showed previously that transformation with v-Ki-ras induces constitutive progesterone secretion in ovarian and adrenocortical cells that are normally steroidogenic (ovarian granulosa and adrenal glomerulosa cells) and also in developmentally related cells that are normally nonsteroidogenic (ovarian surface epithelium and adrenal capsular fibroblasts), but not in unrelated nonsteroidogenic cells, such as muscle fascia fibroblasts and peritoneal mesothelium. In the present study, basal cAMP levels in all transformed ovarian and adrenal cell-lines were increased over basal levels in normal cells, and of transformed muscle fascia and mesothelial cell-lines. As in normal cells, transformation-induced steroidogenesis was stimulated by cAMP and was PKA dependent. A comparison of malignancy-related characteristics showed that transformed cells from nonsteroidogenic organs were more tumorigenic in vivo and less sensitive to growth inhibition by cAMP in vitro than transformed ovarian and adrenocortical cells. The results show that the abnormal, constitutive steroidogenesis induced by the viral form of the Kirsten ras oncogene (v-Ki-ras) in certain cell types is associated with tissue-specific increases in basal cAMP levels. Thus, although the ras oncogenes function primarily through other signal transduction pathways, transformation with ras oncogenes alters PKA-mediated signal transduction in a manner that is developmentally determined.(ABSTRACT TRUNCATED AT 250 WORDS)
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To investigate the physiological and pathological in vivo functions of molecularly cloned genes, the transgenic mouse is one of the most useful experimental animal systems. Many kinds of transgenic mice carrying papillomavirus genes have been produced, and the studies have revealed several new aspects in the field of papillomaviral oncology. Among these transgenic mice, the mechanism of skin carcinogenis in the bovine papillomavirus (BPV) transgenic mouse has been well characterized, demonstrating that numbers of genetic alterations in specific cellular genes were deeply involved in tumor progression as well as in the expression of transforming genes encoded by the viral genome. Comparable mechanisms were found in testicular tumorigenesis in the HPV 16 E6E7 transgenic mouse. Here we discuss the mechanism of testicular tumorigenesis in the HPV 16 E6E7 transgenic mouse together with that of skin carcinogenesis in the BPV transgenic mouse in order to clarify some part of papillomavirus-associated carcinogenesis.
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The authors classified sixty chronic renal failure (CRF) patients receiving hemodialysis (HD) treatment into four groups for clinical study. Forty patients received HD for more than five years and the remaining twenty patients received HD for less than two years. These two groups were further divided into two subgroups according to whether they took Rocaltrol or not. The levels of parathyroid hormone (PTH), calcitonin (CT), alkaline phosphatase (AKP) and bone X-ray were studied in each patient. The results showed: the levels of PTH and CT were obviously increased in all the patients. The levels of PTH and CT were higher in the patients having received HD for more than five years than those for less than two years. They were also higher in patients who had not taken Rocatrol than those who had. Ninety-five percent of the patients having received HD for more than five years had renal osteodystrophy (ROD) without receiving Rocaltrol treatment, while only sixty-five percent of the patients developed ROD with Rocatrol treatment. The longer the HD time, the higher the ROD incidence. The cause, prevention and treatment of ROD were discussed.
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OBJECTIVE: To investigate the relationship between intrauterine contraceptive devices (IUD) induced menorrhagia and endometrial spiral arteriolar contractive function and endometrial superficial vessels thrombus formation function. METHODS: Sixty five subjects were admitted and divided into IUD bleeding group (25 cases), IUD non-bleeding group (20 cases) and IUD non-user group (20 cases). The samples were obtained by curettage within 24 hours prior to menstruation and observed under light and electron microscope. The morphologic changes of endometrial micro-vessels, spiral arterioles were observed and diameter of spiral arterioles were measured. RESULTS: Compared with IUD non-user group, the degenerative changes of spiral arteriolar wall were more severe and the dilatation of spiral arteriolar lumen was obvious especially in spongious layer. In IUD non-bleeding group, these changes were mild. The platelet and fibrin thrombus count was the highest in IUD non-bleeding group and the lowest in IUD bleeding group. CONCLUSIONS: These results suggested that IUD induced menorrhagia might correlated with poor contraction of spiral arterolars in spongious layer and poor thrombus formation. Mild degeneration and dilatation of spiral arterioles and a lot of thrombus were seen in IUD non-bleeding group, and this might be the cause that the mentrual blood loss in this group did not increase obviously.
In a newborn rat model of sepsis, the changes of nitric oxide and the protective effects of methylene blue or/and dexamethason were investigated. The results revealed that plasma nitric oxide levels were elevated at 6 h and peaked at 12 h after bacterial challenge. The treatment with methylene or/and dexamethasone was found to blunt hypoglycemia and hyperlacticemia, to reduce the occurrence rate of loss of response to pain, and to prolong the survival time. Moreover, therapy by dexamethasone was shown to decrease the 24 h mortality. The results suggested that nitric oxide play an important role during the course of fatal P. aeruginosa sepsis, but it is clear that the clinical value of nitric oxide and its inhibitors need to be further studied.
It was found in our previous studies that two Chinese herbs Astragali and Angelica (A&A) together with high protein diet could ameliorate the lowering of serum albumin level and increase the synthesis rate of protein as shown by 15N-glicine tracer priming protein turnover study in nephrotic rats. Further experiment was designed to investigate the role of A&A and high protein intake in protein dynamic study and nitrogen balance in nephrotic patients. The level of serum total protein (STP), serum albumin (SA), urinary protein loss (UP), serum cholesterol (Cho) and index number of protein turnover and nitrogen balance in 7 patients were measured before and after treatment of 30 days with A&A. The results showed that after treatment the patients had significantly increased STA and SA (44.3 +/- 5.60 vs 49.7 +/- 6.80 P < 0.01; 22.6 +/- 0.42 vs. 29.4 +/- 7.40 P < 0.05), decreased UP and Cho (6.54 +/- 1.83 vs 4.63 +/- 1.33 P < 0.05; 9.69 +/- 2.31 vs. 7.82 +/- 1.95 P < 0.05) and increased net rates of total protein synthesis (1.06 +/- 0.03 vs 1.27 +/- 0.12 P < 0.05). It is concluded that A&A together with high protein intake could improve the disorder of protein metabolism and increase the level of serum protein by improving the net rate of protein synthesis in nephrotic patients.
Humans and hominoid primates lack the enzyme urate oxidase, which catalyzes the oxidation of uric acid to allantoin. In rats and most other mammals, urate oxidase is present as a crystalloid core within the peroxisomes of liver parenchymal cells. To determine whether functionally active recombinantly expressed urate oxidase can be targeted to the peroxisome as well as display the crystalloid core-like structure, we expressed rat urate oxidase cDNA in African green monkey kidney cells (CV-1 cells) under the control of a cytomegalovirus promoter. Cell lines stably expressing urate oxidase were isolated. Northern blot analysis revealed a 1.3-kb transcript and immunoblot analysis confirmed the presence of urate oxidase in the stably transfected cells. The recombinant urate oxidase expressed in CV-1 cells was functionally active. Immunofluorescence microscopy revealed that the expressed protein was visualized as discrete granules in the cytoplasm. Electron microscopy and immunocytochemical localization studies showed that the recombinantly expressed protein formed distinct crystalloid core structures with bundles of tubules within single membrane limited cytoplasmic organelles. On cross section, the recombinant urate oxidase tubular structures are arranged as circles of 10 surrounding a slightly larger circle. This arrangement is reminiscent of urate oxidase-containing cores in rat liver peroxisomes. Immunocytochemical studies confirmed that the recombinantly expressed urate oxidase is correctly targeted to the catalase-containing peroxisomes in these CV-1 cells.
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