Helicobacter bilis-induced inflammatory bowel disease in scid mice with defined flora.

Helicobacter bilis has been isolated from aged inbred mice with multifocal chronic hepatitis and from scid mice with diarrhea, proliferative typhlitis, and colitis. To determine the pathogenic potential of H. bilis, we inoculated 4-week-old female Tac:Icr:Ha(ICR)-scidfDF mice by intraperitoneal injection of approximately 10(8) CFU of H. bilis in phosphate-buffered saline (PBS) (n = 15) or PBS alone (n = 10) and necropsied them at 7 weeks postinfection. Sham-inoculated mice had no significant gross or histopathological findings. In contrast, all 15 experimentally inoculated mice (confirmed to be H. bilis-colonized by culture and PCR of cecal contents) exhibited varying degrees of inflammatory bowel disease (IBD). Proliferative typhlocolitis was characterized by focal to segmental areas of crypt hyperplasia and a predominantly histiocytic inflammatory cell infiltrate. Labeling indices for 5-bromo-2'-deoxyuridine incorporation were increased approximately 2.5-fold in the ceca and colons of H. bilis-inoculated mice. This is the first study to demonstrate experimentally that infection with H. bilis causes IBD in scid mice with defined flora. This result both confirms a pathogenic role for H. bilis in mice and provides a new model relating a specific microbial agent and IBD.     

Gastric helicobacter infection induces a Th2 phenotype but does not elevate serum cholesterol in mice lacking inducible nitric oxide synthase

Persistent Helicobacter felis infection in (C57BL/6 x 129SvEv)F1 mice induces chronic gastritis. Expression of inducible nitric oxide synthase (iNOS) is upregulated in response to Helicobacter infection. In this study, 20 10-week-old iNOS-/- mice and 20 wild-type [(C57BL/6 x 129SvEv)F1] mice were infected with H. felis by oral gavage and were assessed histologically and serologically at 32 weeks postinfection. Equal numbers of uninfected controls were sham inoculated. The mice were scored for severity of gastric inflammation, hyperplasia, glandular atrophy, and mucous metaplasia in the corpus and for the level of helicobacter colonization. The immunoglobulin G1 (IgG1), IgG2a, and IgG2c antibody responses to H. felis were determined. As a secondary measure, serum cholesterol levels were assessed. iNOS-/- mice have a propensity for increased serum cholesterol, and although controversial, several human epidemiologic studies have demonstrated an association between Helicobacter infection and several risk factors for cardiovascular disease, including elevated serum cholesterol. Nevertheless, no differences in serum cholesterol levels were observed between the H. felis-infected and -uninfected iNOS-/- mice in this study. The uninfected animals had minimal to no gastric pathology. The gastric pathology scores for the infected animals were reduced significantly in the iNOS-deficient mice relative to those for the wild-type mice (all P <0.01). Helicobacter-infected iNOS-/- mice had chronic lymphoid infiltration and negligible to mild glandular atrophy and mucous metaplasia in the fundic mucosa, while H. felis-infected wild-type mice had severe atrophic and metaplastic mucosal changes. The atrophic gastritis in the infected wild-type mice, particularly the female mice, was also accompanied by greater granulocytic infiltration, antral hyperplasia, and diminished antral colonization, unlike that in the infected iNOS-/- mice. iNOS-/- mice developed significantly lower Th1-associated IgG2c antibody responses to H. felis (P <0.0003); the Th2-associated IgG1 responses were similar (P=0.09), suggesting a greater effect of the iNOS defect on Th1 responses. H. felis colonization was significantly greater in the iNOS-deficient mice. These findings are indicative of an impaired Th1 component of the H. felis-induced inflammatory response when the influence of iNOS is removed.     

Immune regulatory mechanisms influence early pathology in spinal cord injury and in spontaneous autoimmune encephalomyelitis

Injuries to the central nervous system (CNS) trigger an inflammatory reaction with potentially devastating consequences. In this report we compared the characteristics of the inflammatory response on spinal cord injury (SCI) caused by a stab wound between the T7 and T9 vertebrae and spontaneous experimental autoimmune encephalomyelitis (EAE). SCI and EAE were compared in two types of myelin basic protein Ac1-11-specific T-cell receptor transgenic mice: T/R+ mice harbor regulatory T cells, and T/R- mice lack regulatory T cells. Our results show that 8 days after SCI, T/R- mice developed a strong T-cell infiltrate in the spinal cord, with remarkable down-modulation of CD4 expression that was accompanied by a local increase in Mac-3+ and F4/80+ reactivity and diffuse local and distal astrogliosis. In contrast, T/R+ mice exhibited a modest increase in CD4+ cells localized to the site of injury, without CD4 down-modulation; focal astrogliosis was restricted to the site of the lesion, although Mac-3+ and F4/80+ cells were also present. Similarly to T/R- mice that underwent SCI, T cells displaying down-modulated CD4 expression were found in the CNS of older T/R- mice afflicted by spontaneous EAE. Overall, our results suggest that common mechanisms regulate T-cell accumulation in CNS lesions of different causes, such as mechanic lesion or autoimmune-mediated damage.     

Plasminogen activator inhibitor-1 as a measure of vascular remodelling in breast cancer

The generation of urokinase plasminogen activator (uPA) by tumours is an important pathway for neoplastic cell invasion and metastasis. Indeed in several tumour types, elevated levels of uPA, its receptor (uPAR) or its inhibitor plasminogen activator inhibitor-1 (PAI-1) is associated with a poorer prognosis. Since endothelial cells also use this proteolytic system to remodel the extracellular matrix during angiogenesis and since angiogenesis, as assessed by microvessel density, is also a predictor of patient survival, this study was designed to investigate the relationship between angiogenesis and the urokinase system in breast tumours. The aims were to assess whether the uPA, uPAR and/or PAI-1 correlates with angiogenic activity and could therefore be a useful objective clinical measure of tumour neovascularization; and to clarify whether the poor outcome associated with high levels of the urokinase system is due to its association with angiogenesis. The study also sought to examine the relationship between the uPA system and vessel remodelling using loss of a basement membrane epitope (LH39) normally associated with established capillaries. The cytosolic levels of uPA, PAI-1 and uPAR were therefore measured by enzyme linked immunoabsorbent assay, together with tumour vascularity, in 136 well-characterized invasive breast carcinomas. There were significant relationships between uPA and uPAR (Spearman r=0.37, p<0.0001), uPA and PAI-1 (Spearman r=0.19, p=0.03) and between uPAR and PAI-1 (Spearman r=0.23 p=0.01). A significant correlation was also observed between PAI-1 and vessel remodelling (Spearman r=0.34, p=0.04), patient age (p=0.01), nodal status (p=0.047) and tumour grade (p=0.04), but no association between tumour vascularity and PAI (p=0.96), uPA (p=0.69) or uPAR (p=0.81) was present. No significant association was seen between any of the urokinase variables and expression of the angiogenic factor thymidine phosphorylase. Furthermore, no significant associations were found between any of the studied parameters and overall survival in a univariate analysis of the cancer patients. A multivariate Cox proportional hazard model of overall survival showed that uPA (p=0.15), but not uPAR (p=0.52) or PAI-1 (p=0.61), gave no additional prognostic information. These findings show that uPA may work via an independent pathway to angiogenesis and therefore combined blockade of uPA and angiogenesis may have additional therapeutic benefits. It also shows, as recently demonstrated in animal models, that PAI-1 may be a key regulator of vascular remodelling in human cancer.     

Decline in perinatal HIV transmission in New York State (1997-2000)

BACKGROUND: Perinatal HIV transmission has declined significantly in New York State (NYS) since implementation of a 3-part regimen of zidovudine prophylaxis in the antenatal, intrapartum, and newborn periods. This study describes the factors associated with perinatal transmission in NYS from 1997 to 2000, the first 4 years of NYS's comprehensive program in which all HIV-exposed newborns were identified through universal HIV testing of newborns. METHODS: This population-based observational study included all HIV-exposed newborns whose infection status was known and their mothers identified in NYS through the universal Newborn HIV Screening Program (NSP) from February 1997 to December 2000. Antepartum, intrapartum, newborn, and pediatric medical records of HIV-positive mothers/infants were reviewed for history of prenatal care, antiretroviral therapy (ART), and infant infection status. Risks associated with perinatal HIV transmission were examined. RESULTS: Perinatal HIV transmission declined significantly from 11.0% in 1997 to 3.7% in 2000 (P < 0.05). Prenatal ART was associated with a decline in perinatal HIV transmission both for monotherapy (5.8%, relative risk [RR] = 0.3, 95% confidence interval: 0.2%-0.5%) and combination therapy [2.4%, RR = 0.1, 95% confidence interval: 0.1%-0.2%) compared with no prenatal antiretroviral prophylaxis (P < 0.05). CONCLUSIONS: Public health policies to improve access to care for pregnant women and advances in clinical care, including receipt of appropriate preventive therapies, have contributed to declines in perinatal HIV transmission in NYS.     

Protection of Chinese hamster cells against the cytotoxic and mutagenic effects of alkylating agents by transfection of the Escherichia coli alkyltransferase gene and a truncated derivative

The cytotoxic and mutagenic effects of various monofunctionaland bifunctional alkylating agents have been assessed in V79Chinese hamster cells that express either the entire O⁶-alkylguanine(O⁶AG) and alkylphosphotriester alkyltransferase (ATase) gene(clone 8 cells) or a truncated form that codes only for O⁶AGATase activity (clone SB cells). Protection ratios, as determinedby D₃₇ values, were greater for clone 8 cells than for SB cells.Significant protection against the mutagenic effects of N-methyl-N-nitrosoureaand ethylmethanesulphonate at the hypoxanthine phosphoribosyltransferase(HPRT) locus was observed in clone 8 and SB cells. Streptozotocinand the haloethyl nitrosoureas, chlorozotocin and bis-chloroethylnitrosoureawere less efficient in inducing HPRT-deficient mutants and asmaller degree of protection was afforded by the transfectedgenes. This is possibly due to the propensity of these compoundsto induce multi-locus deletions. Southern analysis of DNA fromclone 8 and SB cells indicated the presence of multiple copiesof the plasmid integrated into clone 8 cells but few copiesin clone SB cells. The copy number did not change but ATaselevels fell when cells were grown in the absence of G418. ²Present address: Corporate Biosciences Laboratory, ICI plc,The Heath, Runcorn, Cheshire, UK      

Laser induced thermal injury of rabbit cornea and treatment with anti-inflammatory agents

A moderately severe thermal injury of the central cornea of 48 Dutch-belted rabbit eyes was produced with a carbon (CO₂) laser. The lesions were photographed with a slit lamp (SL) camera immediately following the injury and at 1, 2, 4, 7, 14, 21, 30 and 60 days after the exposure. Lesion size, opaqueness, and depth were graded clinically by SL biomicroscopy at the same intervals. No significant differences were found (p 0.05) between groups of eyes treated with flurbiprofen (0.03%), prednisolone acetate (1%), and vehicle control four-times-a-day for three weeks following injury. Additionally, eyes were studied histopathologically at 3 and 60 days following injury by light and transmission electron microscopy, and clinically at 30 and 60 days by endothelial specular microscopy. Important clinical and histopathological findings included coagulative necrosis of the corneal epithelium, epithelial sloughing, fusion of stromal collagen, stromal edema and inflammatory cell infiltration, stromal scar formation, corneal thinning, endothelial hyperplasia and metaplasia, fibrinous anterior chamber reaction with hypopyon, and retrocorneal fibrous membrane formation.     

Direct membrane method for the study of interface-controlled transport of cholesterol in aqueous media

Studies were designed to demonstrate the use of a silicone rubber membrane diffusion cell in the mechanistic study of cholesterol mass transfer in aqueous media. The method is shown to be simple, precise, and well suited for delineating conditions which facilitate cholesterol transport. Traditional membrane diffusion resistance was determined with cholesterol solubilized in the nonionic surfactant, polyoxyethylene(10)-nonylphenol ether. The use of a charged surfactant additive, either sodium oleate or benzyldimethyltetradecylammonium chloride, reduced cholesterol membrane flux in a manner consistent with a transport barrier residing in the membrane and micelle interfacial regions. Quantitative determination of total transport resistance was good (CV of greater than 95%) for cases more than 99% interface controlled. Interfacial resistance imparted by the charged surfactant additive was essentially abolished by strong electrolyte (sodium chloride). Electrolyte was utilized in either the upstream or the downstream aqueous compartment to enhance cholesterol transport by a mechanism which is consistent with a marked increase in the frequency of micelle collision with the corresponding membrane surface. When the downstream interfacial component of total transport resistance was "short circuited" by electrolyte in sequential transport runs using the same membrane, a "dumping" of cholesterol by the membrane compartment was observed. Limited studies with a second nonionic surfactant, polyoxyethylene(15)-tridecyl ether, suggest that the structure of separate micelle components may also be related to cholesterol mass transfer which occurs via a micelle collision in the interfacial region.     

Inhibition of aflatoxin B1 -hepatocarcinogenesis in rats by {beta}-naphthoflavone

Effects of ß-naphthonflavoe (ßNF) on theactivity of hepatic microsomal aflatoxin B₁ (AFB₁)-4-hydroxylase- the cytochrome P-450-dependent enzyme system which catalyzesthe metabolism of AFB₁ to AFM₁ - and on AFB₁ induced in vivohepatocarcinogenesis were investigated in weanling male Fischerrats. A single i.p. injection of ßNF in doses of 20mg/kg and 150 mg/kg induced AFB₁ -4-hydroxylase 3- and 4-fold,respectively, 48 h post injection. Feeding of diet containing0.01% ßNF for a period of 9-weeks induced AFB₁ 2-fold.AFB₁, given by intubatlon in a dose of 25 µg five times/weekfor 8 weeks, produced 42 weeks later a 100% incidence of liverlesions (neoplastic foci, nodules or tumors), but feeding ßNFin diet at a con centration of 0.015% for one week prior toand during the 8 weeks of AFB treatment inhibited AFB₁ hepatocarcinogenesis by -7%. These results are in accord with the suggestionthat AFB₁ induction may be associated with the inhibition ofAFB₁ carcinogenesis, possibly occurring as a consequence ofaccelerated detoxi-fication of AFB₁ via its conversion to AFM₁