Mechanisms contributing to renal resistance to atrial natriuretic peptide in rats with common bile-duct ligation

Blunted volume expansion (VE) natriuresis and renal resistance to atrial natriuretic peptide (ANP) characterize states of pathological sodium retention. This study examined rats 1 to 3 wk after common bile-duct ligation (CBDL), at which time they had hyperbilirubinemia and hypoalbuminemia. Sham-operated normal rats (Sham) showed an increased sodium excretion rate (UNaV) from 1.0 +/- 0.1 to 16.3 +/- 3.9 muEq/min in response to acute VE (iv saline, 2 mL/100 g body wt over 5 min), whereas CBDL rats had a blunted response that was apparent after 1 wk and became maximal at 2 and 3 wk (0.3 +/- 0.1 to 3.2 +/- 0.4 muEq/min at 3 wk, P < 0.01 versus Sham response). The peak urinary cGMP excretion rate (UcGMPV) was also blunted (37.9 +/- 3.6 versus 87.5 +/- 8.3 pmol/min, P < 0.01) despite an even greater increase in plasma ANP concentration (Sham, 9.6 +/- 0.4 pg/mL in hydropenia to 22.8 +/- 2.6 pg/mL after VE; CBDL, 15.3 +/- 2.3 to 41.8 +/- 6.8 pg/mL). ANP-dependent cGMP accumulation by isolated inner medullary collecting duct (IMCD) cells from both Sham and CBDL rat kidneys was dose-dependent; however, at higher concentrations of ANP (> 10(-8) M), accumulation by cells from CBDL rats was significantly blunted, indicating resistance to ANP. Binding of 125I-ANP to IMCD cells was not different in CBDL rats compared with Sham control rats. Renal denervation improved but did not completely reverse the blunted natriuresis, and ANP resistance persisted in IMCD cells from denervated kidneys of CBDL rats. Incubation of IMCD cells with the phosphodiesterase inhibitors isomethylbutylxanthine or Zaprinast (each at 10(-3) M) restored ANP responsiveness in both innervated and denervated kidneys from CBDL rats, and intrarenal infusion of Zaprinast (10 micrograms/min) corrected the blunted increase in UNaV and UcGMPV after VE in rats with CBDL. These results suggest that ANP resistance in a model of abnormal sodium metabolism devoid of intrinsic renal disease may be related to increased activity of phosphodiesterase in renal target cells for ANP as well as to heightened renal nerve activity.

Variable expression of Epstein-Barr virus latent membrane protein I in Reed-Sternberg cells of Hodgkin's disease

Reed-Sternberg cells (RS cells) of Hodgkin's disease (HD) are frequently infected with Epstein-Barr virus (EBV) and express EBV-encoded nonpolyadenylated RNA transcripts (EBER)-1. EBV latency has been classified into three distinct forms: Latency I, expressing only one of the latent proteins, EBV nuclear antigen (EBNA)-1, latency II, coexpressing EBNA-1 and LMPs, and latency III, expressing all latent viral proteins. RS cells express LMP-1 in addition to EBNA-1 and are considered to be EBV latency II frequently encountered in nasopharyngeal carcinoma. We examined 13 cases of EBV-infected HD by combined EBER-1 in situ hybridization and immunostaining for LMP-1. All of the RS cells expressed EBER-1, but a substantial number of EBER-1+ RS, cells were negative for LMP-1. The percentage of LMP-1+ RS cells out of EBER-1+ RS cells varied from 7% to 100% (average 69%). In this study, we showed that all EBV-infected RS cells were not restricted to latency II, and some belonged to latency I.

Scavenger receptor-mediated adhesion of microglia to beta-amyloid fibrils

A pathological hallmark of Alzheimer's disease is the senile plaque, containing beta-amyloid fibrils, microglia and astrocytes. Beta-amyloid fibrils exert a cytotoxic effect on neurons, and stimulate microglia to produce neurotoxins, such as reactive oxygen species. Mononuclear phagocytes, including microglia, express scavenger receptors that mediate endocytosis of oxidized low-density lipoproteins, and adhesion to glucose-modified extra-cellular matrix proteins. Here we report that class A scavenger receptors mediate adhesion of rodent microglia and human monocytes to beta-amyloid fibril-coated surfaces leading to secretion of reactive oxygen species and cell immobilization. Thus, class A scavenger receptors are potential therapeutic targets in Alzheimer's disease.

Gamma-interferon upregulates transferrin receptors and decreases membrane microviscosity in K562 cells

We investigated the effect of gamma-interferon (gamma-IFN) on three cellular parameters: cell membrane fluidity and expression of two antigens that have been associated with cell proliferation, namely transferrin receptor (Tf-R: a cell surface protein) and Ki-67 antigen (Ki-67: a nuclear protein). We observed small, yet significant changes in the first two parameters, but not the third parameter. These were investigated in K562 cells, a human chronic myelocytic leukemia cell line. These results suggest that the microviscosity changes and the surface Tf-R density were closely associated, and that gamma-IFN was involved in increasing proliferative activity of the cells by decreasing membrane fluidity and upregulating Tf-R expression.

The Fas antigen is detected on immature B cells and the representative cell lines show Fas-mediated apoptosis

The expression and functions of Fas antigen, a major regulator of apoptosis, in T-cell selection have been intensively investigated, but little is known about its expression i immature B cells which are also selected in the bone marrow, and plasma cells which are at the terminal stage of B-cell differentiation and are designed to die. We examined bone marrow cells and found Fas antigen on these cells at low levels. Next we analysed Fas expression and susceptibility to anti-Fas antibody-mediated apoptosis on B-cell lines representing various stages of differentiation. We also examined the expression of Bcl-2 and Bax on these lines, which were intimately related to apoptosis. Fas antigen was almost negative on pre-pre-B cell lines and was detected on pre-B-cell lines at low levels. All plasma cell lines expressed Fas at a low to moderate level. Some cell lines with peripheral B-cell phenotype expressed Fas antigen. Except for the Burkitt cell lines and one plasma cell line, susceptibility to Fas-mediated apoptosis depended on Fas expression. Bcl-protein was detected on all but one cell line and Bax was detected on 15/23 lines, but neither were related to cellular differentiation or Fas expression.

The value of perioperative echocardiography in percutaneous balloon mitral valvuloplasty

In order to investigate the value of perioperative echocardiography in percutaneous balloon mitral valvuloplasty (PBMV), two-dimensional echocardiography (2-DE), Doppler echocardiography and color Doppler flow imaging (CDFI) were employed prior to PBMV in 52 patients and during or after PBMV in 15 patients. The results showed that TTE and TEE were helpful in the selection of candidates for 2-DE transseptal and balloon dilation procedures. Continuous monitoring of 2-DE, Doppler echocardiography and CDFI during PBMV could make this procedure safer and more effective, reduce X-ray exposure and avoid complications. Echocardiography was useful in fluoroscopy and could be used for evaluation of the effects of operation.

Binding of human leukocytes to fibronectin is augmented by an anti-CD44 mAb (TL-1) and blocked by another anti-CD44 mAb (Hermes-3) but not by anti-VLA-4/VLA-5 mAbs

Fibronectin (FN) forms meshworks in extracellular spaces, and it plays an important role in cellular trafficking. Lymphoid cells are activated by binding to FN of the VLA-4 and VLA-5 receptors. CD44 also acts as a receptor of FN, but the mechanism and physiologic regulation of their binding are poorly understood. We have developed an anti-CD44 monoclonal antibody (mAb) (TL-1) in which lymphoid cells are activated and form homotypic cell aggregation. In this study, we found that the adhesion of CEM, HSB2, and LAD lymphoid cells to FN was augmented by TL-1 treatment and was apparently blocked by another anti-CD44 mAb (Hermes-3), but TL-1 Fab' fragments treatment did not induce FN-binding. A similar phenomenon is reported in the binding of the CD44 molecule to HA. This augmentation was not inhibited by the CS1 and RGD peptides of FN or by anti-VLA-4 and -VLA-5 mAbs; it was energy-dependent and associated with cytoplasmic actin filaments. Tl-1 treatment did not alter the cell surface expression of CD44 molecules. These findings above suggested that activated and/or altered cell surface distribution of CD44 molecules via a conformational change augmented the avidity of its binding to FN, which may be similar to lymphocyte-hyaluronate and lymphocyte-endothelial cell binding. As the Hermes-3 binding site is also involved in the interaction between lymphocytes and endothelial cells, activation of lymphocytes via CD44 molecules may facilitate the binding of lymphocytes to endothelial cells, extravasation, and migration to inflammatory sites rich in FN.

[Epidemiological analysis of poliomyelitis cases in 1994, China]

In 1994, the number of reported polio cases was 307 in China. This number was 53% lower than that in 1993, and was the lowest record ever in China. In 1994, the distribution of polio cases was highly dispersed and the number of outbreak was reduced obviously. Of 225 counties which reported polio cases in 1994, polio outbreak occured in 2 counties. Cases due to polio outbreak accounted for 4.2% of the total cases. The distribution of polio wild virus was narrow but the regional difference still existed. In the southeast, high risk region for polio consisting Guangdong, Hainan, Fujian three provinces, the number of polio cases decreased remarkably in 1994. On the contrary, in the southwest region which, consisting Guangxi, Yunnan, Guizhou, Sichuan four provinces, the number of polio cases increased obviously, accounted for approximately a half of the total number in 1994. During the coming 1 to 2 years, we should emphasis on these regions and provinces where high incidence was noticed in our polio eradication program. Those provinces should include Xinjiang, Fujian. Hubei three provinces that polio wild virus was identified in 1994, and Guangxi, Sichuan, Guizhou, Yunnan in the south west region as well. We should further increase Polio vaccination coverage of children especially floating and unplanned ones through strengthening routine immunization and carring out new national immunization day activity.

[Evaluation of acute flaccid paralysis (AFP) surveillance system in 1994]

Increased by 40.2% compared with 1993, 3142 acute flaccidparalysis cases were reported from AFP surveillance system in 1994. A total number of 1297 counties had AFP cases reported, accounting for 45.1% of total amount of counties. Out of 3142 AFP cases, 307 were confirmed, coming from 225 counties. For children under 15 years old, the reported AFP incidence was 1.1/10(5), non-polio AFP rate was 0.83/10(5), much higher than 0.37/10(5), in 1993. 48.5% of the total AFP cases had double stool specimen taken within 0-14 days after paralysis. 79% AFP cases had been investigated within 48 hours after being reported. Some of the major monitoring indicators of AFP surveillance system were close to the WHO criterion, but the percentage of AFP cases reported within 48 hours of careseeking and AFP cases with follow-up visit after 60-70 days of paralysis were very low. Furthermore, 77.9% of the confirmed cases were diagnosea clinically by residual paralysis, so did the 46.4% of discarded cases. It is in urgent need to increase the percentage of cases classified by laboratory test.

Gene therapy of Parkinson disease model rat by direct injection of plasmid DNA-lipofectin complex

Lipofectin-mediated gene transfer was used to introduce plasmid harboring the tyrosine hydroxylase (TH) gene into the striatum of rats with lesions of the nigrostriatal pathway. The rotational asymmetry of Parkinson disease model rat was reduced quickly and significantly, suggesting that plasmid-DNA-transfected brain cells can generate L-dopa locally in the striatum in quantities sufficient to compensate partially for the loss of intrinsic striatal dopaminergic input. Immunohistochemical staining and reverse transcription polymerase chain reaction (RT-PCR) also confirm that striatal cells can express exogenous TH gene. Such in vivo plasmid DNA transfer strategy may be useful in other neurologic disease therapy, especially acute brain insults.

[Surgical treatment for iatrogenic damage at the confluence of hepatic duct]

Since 1989, 4 patients with iatrogenic bile duct injuries at the level of bifurcation were treated. Among them, the bifurcation together with both right and left hepatic duct had had wrongly been resected in 2 cases. The bifurcation was partially resected in the other 2 cases. The establishment of a permanent hepaticoentertostomy is essential. Abnormal bile flow would impede surgical effect, hence in the author's opinion, peripheral hepaticoenterostomy such as Longmire's procedure is unsuitable for iatrogenic bile duct injuries. The author's special technique for adequate exposure and accurate dissection of intrahepatic bile ducts is described. Four cases have been followed up for 7 months to 5 years with good result.

Atrial natriuretic peptide suppresses the transcription of its guanylyl cyclase-linked receptor

Atrial natriuretic peptide (ANP) treatment of rat aortic smooth muscle cells suppressed both 125I-ANP binding and ANP-dependent cGMP accumulation, suggesting reductions in the type C (NPR-C) and type A (NPR-A) natriuretic peptide receptor populations, respectively. NPR-A, but not NPR-C, mRNA levels were reduced in a dose-dependent fashion by ANP. The latter effect appeared to be due, at least in part, to suppression of NPR-A gene promoter activity. ANP effected a dose- and time-dependent reduction in a transiently transfected NPR-A luciferase reporter (-1575LUC). Analysis of 5' deletion mutants of the NPR-A promoter demonstrated that the ANP-dependent sequence lies between -1575 and -1290 relative to the transcription start site. Inhibition of the ANP promoter was also effected by brain natriuretic peptide, type C natriuretic peptide, and 8-bromo-cGMP, but not by the NPR-C-selective ligand cANF. In the case of 8-bromo-cGMP, the responsive element(s) was localized to the same 285-base pair region linked to the ANP effect above. These findings indicate that ANP autoregulates its own receptors in these cells and, at least in the case of NPR-A, it does so through suppression of receptor gene expression and receptor synthesis. This suppression may operate through a cGMP-dependent element located more than a kilobase upstream from the transcription start site.

Alteration of the adrenal antioxidant defense system during aging in rats

The goal of this study was to determine to what extent aging affects the antioxidant defense system of the rat adrenal and to evaluate the impact of any change in this system on the recognized age-related decline in steroidogenic capacity of adrenocortical cells. The studies were conducted on young (2-5 mo) and aging (12-27 mo) Sprague-Dawley rats and involved procedures measuring steroidogenesis; oxidative damage to tissue; non enzymatic antioxidants such as vitamin C, E, and glutathione; and tissue antioxidant enzyme (Mn and CuZn superoxide dismutases, catalase, and glutathione peroxidase) activity and expression (mRNA, protein mass, and location). Some measurements were made also on rats maintained on vitamin E-deficient diets. The data show that adrenals from young animals are especially well protected against oxidative events; i.e., these adrenals show the least endogenous lipid peroxidation and the highest level of resistance to prooxidant-induced damage (of various tissues measured) and show exceedingly high levels of tissue antioxidants. Aging, on the other hand, results in oxidative changes in adrenal tissue that are generally linked in time to a reduction in efficiency of the normally protective antioxidant defense system and to the decline in corticosterone production. We speculate that these events are causally related, i.e., that the age-related reduction in oxidative mechanisms in adrenal tissues leads to oxidative damage of membrane or cytosolic factors important to cholesterol transport, and, as a consequence of this damage, cholesterol cannot reach appropriate mitochondrial cholesterol side chain cleavage sites, and corticosterone production fails.

Crossover and noncrossover recombination during meiosis: timing and pathway relationships

During meiosis, crossovers occur at a high level, but the level of noncrossover recombinants is even higher. The biological rationale for the existence of the latter events is not known. It has been suggested that a noncrossover-specific pathway exists specifically to mediate chromosome pairing. Using a physical assay that monitors both crossovers and noncrossovers in cultures of yeast undergoing synchronous meiosis, we find that both types of products appear at essentially the same time, after chromosomes are fully synapsed at pachytene. We have also analyzed a situation in which commitment to meiotic recombination and formation of the synaptonemal complex are coordinately suppressed (mer1 versus mer1 MER2++). We find that suppression is due primarily to restoration of meiosis-specific double-strand breaks, a characteristic of the major meiotic recombination pathway. Taken together, the observations presented suggest that there probably is no noncrossover-specific pathway and that restoration of intermediate events in a single pairing/recombination pathway promotes synaptonemal complex formation. The biological significant of noncrossover recombination remains to be determined, however.

Ligation of HLA class II molecules promotes sensitivity to CD95 (Fas antigen, APO-1)-mediated apoptosis

CD95 (Fas antigen/APO-1) is up-regulated in activated lymphocytes, and monoclonal antibody (mAb) to CD95 induces apoptosis. HLA class II molecules play a key role in antigen presentation, ligation of which induces signal transduction. We examined 18 lymphoid cell lines (15 B cell and 3 T cell lines) to investigate the effects of ligation of HLA class II molecules on CD95-mediated apoptosis. All of the five immature B cell lines were sensitive to anti-CD95 mAb, and ligation of HLA class II molecules promoted CD95-mediated apoptosis. In seven B-blastoid cell lines, two Burkitt lines were resistant to anti-CD95 mAb in spite of high expression of CD95. In three of five non-Burkitt B-blastoid lines, CD95-mediated apoptosis was augmented by treatment with anti-HLA class II mAb, while the other two lines lacking CD95 were resistant to anti-CD95 mAb. Three plasmacytic cell lines showed CD95-mediated apoptosis, but enhancement by anti-HLA class I mAb was slight in one cell line and was not observed in the other two lines. Out of three HLA class II antigen-positive T cell lines, CD95-mediated apoptosis was observed to some degree in one call line but was not promoted by the treatment with anti-HLA class II mAb, and the other two cell lines were resistant to anti-CD95 mAb. Ligation of HLA class II molecules did not alter CD95 expression in the five cell lines examined, except Su-DHL-4 originated from a follicular lymphoma, which showed slight up-regulation. Taken together, ligation of HLA class II molecules apparently promotes CD95-mediated apoptosis in immature B cells and non-Burkitt B blasts. These findings highlight the role of HLA class II molecules in CD95-mediated apoptosis, which may facilitate rapid clearance of functionally useless cells from the immune system and might be involved in negative selection of B cells.

Identification of two new exons and multiple transcription start points in the 5'-untranslated region of the human cathepsin-B-encoding gene

Transcripts for cysteine protease cathepsin B (CTSB) were found to be highly variable in the 5'-UTR (untranslated region). In cDNA clones from a human gastric adenocarcinoma cDNA library, we have identified two new exons (designated 2a and 2b) between exons 2 and 3 in the 5'-UTR of the gene. All of the exons of the 5'-UTR could be alternatively spliced to produce several transcript species. In addition, transcription was initiated from more than one promoter region. Using RT-PCR (reverse transcription-polymerase chain reaction) and primer extension assays, CTSB mRNA species were found to differ among tissues and between a glioblastoma sample and a cell line derived from it. Exons 2a and 2b were detected more frequently in tumor samples than in matched normal samples. Thus, factors related to the cell differentiation and environment seem likely to determine the types of transcripts that are expressed which in turn could influence the overall steady-state level of CTSB mRNAs and their rate of translation. Interestingly, at least three upstream translation initiation codons were observed and could constitute a means of controlling translation initiation.

[Changes in serum granulocyte colony-stimulating factor (G-CSF) in burned patients]

Serum G-CSF level was assayed in 20 burned patients (TBSA > or = 30%) 2 weeks postburn. In 11 of them plasma endotoxin was also measured. The results showed serum G-CSF level was increased in 87.5% (7/8) of burned patients with exceeding 50% TBSA and in 58.3% (7/12) of patients with 30%-50% TBSA, and in the former it was earlier increased (1-5 day postburn) than the latter (5-11 day postburn). Serum G-CSF was increased in 90% of the burned patients with wound sepsis. Increased of serum G-CSF in burned patients, especially in those exceeding 50% TBSA, indicates the occurrence of sepsis.

1,25(OH)2D3 suppresses expression and secretion of atrial natriuretic peptide from cardiac myocytes

We have examined the effects of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] on the expression of the rat atrial natriuretic peptide (ANP) gene and the secretion of the encoded protein product in neonatal rat cardiac myocyte cultures. 1,25(OH)2D3 effected a dose- and time-dependent inhibition of agonist-stimulated ANP secretion, which was accompanied by a reduction in the levels of the ANP mRNA transcript. The latter effect appeared to derive, at least in part, from suppression of ANP gene transcription. Of interest, both the reduction in mRNA levels and the inhibition of transcriptional activity were amplified by simultaneous treatment with retinoic acid, suggesting that heterodimerization of liganded 1,25(OH)2D3 receptor and retinoic acid receptor (likely retinoid X receptor) may underlie the inhibitory mechanism in the cardiac myocyte. Neither the secretory effect nor the effect on transcription proved to be calcium dependent. 22-Oxacalcitriol, a nonhypercalcemic analogue of 1,25(OH)2D3, was equally effective in suppressing ANP mRNA levels and transcription of the gene. These findings add to a growing body of data that imply an important role for 1,25(OH)2D3 in the regulation of cardiovascular function.

Homotypic cell aggregation via conformational change of CD44 molecule induced by anti-CD44 monoclonal antibodies

The homotypic cell aggregation of leukocytes is an unique adhesive event which is caused by cellular activation. Anti-CD44 monoclonal antibody (mAb) induces homotypic cell aggregation of hematopoietic cell lines expressing CD44, but the mechanism of homotypic cell aggregation is poorly understood. We used four mAbs against CD44: TL-1 which was newly developed and seemed to react with a non-hyaluronate binding site, OS/37 and BU52 which recognized a hyaluronate binding site, and Hermes-3 which recognized a non-hyaluronate binding site. TL-1 treatment induced strong homotypic cell aggregation in several types of cell lines including a B cell line from a patient with leukocyte adhesion deficiency syndromes (LAD) and normal peripheral blood lymphocytes (PBL). OS/37 and BU52 also induced weak homotypic cell aggregation. None of these anti-CD44 mAbs-induced homotypic cell aggregations was blocked by antibodies against LFA-1, ICAM-1, VLA-4, or L-selectin. Interestingly, the TL-1-induced homotypic cell aggregation was blocked by Hermes-3 or OS/37, but not by BU52. BU52-induced homotypic cell aggregation was blocked by Hermes-3 or OS/37, but not by TL-1. OS/37-induced homotypic cell aggregation was blocked by Hermes-3, TL-1 or BU52. The blocking experiments with anti-metabolic agents revealed that the induced homotypic cell aggregation was energy-dependent and associated with intracytoplasmic actin filaments. This homotypic cell aggregation did not require de novo protein synthesis, because it was not affected by pretreatment with either cycloheximide or actinomycin D. FACS analysis revealed that TL-1 binding did not affect the intensity of expression of the CD44 molecule on the cell surface.

Fibrin regulates neutrophil migration in response to interleukin 8, leukotriene B4, tumor necrosis factor, and formyl-methionyl-leucyl-phenylalanine

We have examined the capacity of four different chemoattractants/cytokines to promote directed migration of polymorphonuclear leukocytes (PMN) through three-dimensional gels composed of extracellular matrix proteins. About 20% of PMN migrated through fibrin gels and plasma clots in response to a gradient of interleukin 8 (IL-8) or leukotriene B4 (LTB4). In contrast, < 0.3% of PMN migrated through fibrin gels in response to a gradient of tumor necrosis factor alpha (TNF) or formyl-methionyl-leucyl-phenylalanine (FMLP). All four chemoattractants stimulated PMN to migrate through gels composed of collagen IV or of basement membrane proteins (Matrigel), or through filters to which fibronectin or fibrinogen had been adsorbed. PMN stimulated with TNF or FMLP adhered and formed zones of close apposition to fibrin, as measured by the exclusion of a 10-kD rhodamine-polyethylene glycol probe from the contact zones between PMN and the underlying fibrin gel. By this measure, IL-8- or LTB4-treated PMN adhered loosely to fibrin, since 10 kD rhodamine-polyethylene glycol permeated into the contact zones between these cells and the underlying fibrin gel. PMN stimulated with FMLP and IL-8, or FMLP and LTB4, exhibited very little migration through fibrin gels, and three times as many of these cells excluded 10 kD rhodamine-polyethylene glycol from their zones of contact with fibrin as PMN stimulated with IL-8 or LTB4 alone. These results show that PMN chemotaxis is regulated by both the nature of the chemoattractant and the composition of the extracellular matrix; they suggest that certain combinations of chemoattractants and matrix proteins may limit leukocyte movements and promote their localization in specific tissues in vivo.

Natriuretic peptides inhibit DNA synthesis in cardiac fibroblasts

We have examined the effects of the natriuretic peptides on DNA synthesis in primary cultures of neonatal rat cardiac fibroblasts. Binding analysis using 125I-labeled atrial natriuretic peptide identified a single class of high-affinity binding sites (Kd = 0.03 +/- 0.01 nmol/L) in these cells. Of these sites, 80% appear to be of the natriuretic peptide C receptor subtype, with the remainder being A and B receptor subtypes. Northern blot analysis confirmed the presence of all three natriuretic peptide receptors in these cells. Atrial natriuretic peptide (10(-7) mol/L) effected a modest but consistent reduction in both agonist- and stretch-stimulated [3H]thymidine incorporation (17% to 41%). Moreover, brain natriuretic peptide (10(-7) mol/L), C-type natriuretic peptide (10(-7) mol/L), and des-[Gln18,Ser19,Gly20,Leu21,Gly22]-ANF 4-23-NH2 (10(-7) to 10(-6) mol/L) all proved capable of antagonizing growth factor-dependent [3H]thymidine incorporation (the inhibition ranged from 14% to 28%) and cell proliferation, suggesting that all three natriuretic peptide receptor subtypes are involved in the regulation of mitogenesis in these cultures. The inhibition by atrial natriuretic peptide was amplified by cotreatment with phosphodiesterase inhibitors. Similar reduction in [3H]thymidine incorporation was seen after treatment with 8-bromo-cGMP (10(-4) to 10(-3) mol/L) or nitroprusside (10(-4) to 10(-3) mol/L). These results suggest an important paracrine role for the natriuretic peptides in regulating fibroblast growth during cardiac hypertrophy.

[The effects of mupirocin on burned wound with Staphylococcus aureus infection]

The therapeutic results of 41 cases of S. aureus infected burn wound (average 2.1% TBSA, approximately 200 cm2) treated with Mupirocin are reported in this paper. The effects of Mupirocin was obviously superior to that of SD-Ag used in control group. During the observation period the total effective rate of the studied group was 88.9% (control group: 70%, P < 0.05) and the bacterial clearance rate of S. aureus from the wound was 88.8% (control group: 40% P < 0.05). The sensitivity of 30 strains of S. aureus isolated from burn wounds to 11 varieties of antibiotics indicated that the sensitive rate to Mupirocin was as high as 92.68%, only lower that Vanconmycin. The bacteriological assay (MIC < or = 0.25 mg/L, MIC < or = 4 mg/L) also showed high sensitivity of S. aureus to Mupirocin. We suggest Mupirocin be the first choice of topical antibacterial agents for burn wound with S. aureus infection, especially for infection with MRSA.