The estrogen antagonist tamoxifen inhibits carrageenan induced inflammation in LEW/N female rats

Carrageenan induces a measurable inflammatory response in susceptible animals, and mature females are more responsive to carrageenan, than males. In the present study, we tested whether the estrogen antagonist tamoxifen influences carrageenan-induced inflammatory responses. Female LEW/N rats were treated with tamoxifen and compared to a control group of animals injected with vehicle. Tamoxifen significantly reduced estrous phase of estrous cycle during treatment, consistent with its functional anti-estrogen effects. Moreover, tamoxifen significantly decreased exudate volume but did not significantly influence relative white blood cell counts in the exudate. Interestingly, tamoxifen induced differential dose-dependent alterations in peripheral blood lymphocyte subpopulations. Low dose of tamoxifen increased CD25 cells. The high tamoxifen dose significantly increased CD8 blood lymphocyte counts. Our data indicate that tamoxifen treatment decreases carrageenan-induced inflammatory response in female LEW/N rats and suggest therefore that this inflammatory response is, at least in part, estrogen related. Moreover, our results suggest a possible role for tamoxifen in treatment of inflammatory disorders.     

A mutation in Myo15 leads to Usher-like symptoms in LEW/Ztm-ci2 rats

The LEW/Ztm-ci2 rat is an animal model for syndromal deafness that arose from a spontaneous mutation. Homozygous animals show locomotor abnormalities like lateralized circling behavior. Additionally, an impaired vision can be observed in some animals through behavioral studies. Syndromal deafness as well as retinal degeneration are features of the Usher syndrome in humans. In the present study, the mutation was identified as a base substitution (T->C) in exon 56 of Myo15, leading to an amino acid exchange from leucine (Leu) to proline (Pro) within the carboxy-terminal MyTH4 domain in the proteins' tail region. Myo15 mRNA was expressed in the retina as demonstrated for the first time with the help of in-situ hybridization and PCR. To characterize the visual phenotype, rats were examined by scotopic and photopic electroretinography and, additionally, histological analyses of the retinas were conducted. The complete loss of sight was detected along with a severe degeneration of photoreceptor cells. Interestingly, the manifestation of the disease does not solely depend on the mutation, but also on environmental factors. Since the LEW/Ztm-ci2 rat features the entire range of symptoms of the human Usher syndrome we think that this strain is an appropriate model for this disease. Our findings display that mutations in binding domains of myosin XV do not only cause non-syndromic hearing loss but can also lead to syndromic disorders including retinal dysfunction.     

Reexamination of the difference in susceptibility to adjuvant-induced arthritis among LEW/Crj, Slc/Wistar/ST and Slc/SD rats.

The present investigations were performed to assess the differences among rat colonies commonly used for neurophysiological research regarding the development of complete Freund's adjuvant (CFA)-induced arthritis. Inflammatory signs including edema in the paw fluctuated remarkably among individual Wistar (Slc/Wistar/ST) and Sprague-Dawley (Slc/SD) rats, while the inflammatory signs of Lewis (LEW/Crj) rats appeared earlier and was severer and more consistent than Slc/Wistar/ST and Slc/SD rats. Edema in the hind paw developed in 100% of LEW/Crj rats with the lowest dose of CFA (0.6 mg/rat) used as compared with 64% of Slc/Wistar/ST (CFA 1 mg/rat) and 38% of Slc/SD rats (CFA 1.2 mg/rat). Retardation of weight gain was observed in Slc/Wistar/ST and Slc/SD rats in contrast to a severe weight decrease in inflamed LEW/Crj rats after the development of arthritis.     

Natural antibodies in Pseudomonas aeruginosa infections

Studying 347 sera of 49 patients suffering from Pseudomonas aeruginosa infection the mean titre value (MTV) calculated from the exponent of the binary logarithm of natural antibody (NA) titres, was found suitable to characterize the humoral immune status. As long as the organism is in equilibrium with the infection, the NA level rises. In septic shock, before death or at the development of a massive infection, the NA titre decreases rapidly. The decrease may be due partly to the permeability increasing effect of endotoxin and antigen-antibody reactions exerted on the capillaries. Consequently, in the most severe phase of sepsis, when bacteria enter the circulation less NA is available to fight against them. This might be a cause of the still very high lethality of septic shock due to Gram-negative bacteria. Finally, when applying the MTV one always has to consider that despite its advantages it gives less information than the Backhausz immunogram.     

Natural and experimental Helicobacter infections

Current information about Helicobacter infections in humans and various domestic, wild, and research animal species that have been used or have the potential to be used as animal models of human disease is presented. The Helicobacter genus now includes at least 26 formally named species, with additional novel species in the process of being characterized. The natural history, host range with zoonosis potential, pathology, and diagnostic techniques are presented, along with examples of how Helicobacter infection has interfered with unrelated in vivo research. Current recommendations for deriving and managing helicobacter-free animal colonies for research are provided.     

Caprine mycoplasmal mastitis in Nigeria

In a study to investigate the current status of intramammary mycoplasmosis in caprine udders in Nigeria, a total of 57 and 24 milk samples were collected from udders of goats affected by mastitis and from apparently normal goats’ udders, respectively. Acute and chronic mastitis were more commonly observed in goats between 1 and 3 years old. Mycoplasma agalactiae and Mycoplasma capricolum occurred at a significantly higher rate (p<0.05) in udders affected by mastitis than in normal healthy udders. Other mycoplasma occurring in low prevalence include Mycoplasma bovis and Mycoplasma mycoides subsp. mycoides LC. It is concluded that cultural (microbiological) surveillance is necessary for effective treatment and control of the disease in Nigeria.     

PCR-based detection and eradication of mycoplasmal infections from various mammalian cell lines: a local experience

A total of 200 cell lines including different human, monkey, mice, hamster and rat cell types were examined for mycoplasma infection status. PCR assay using generic-specific universal primers showed that 40 (20%) of the cell lines are contaminated with mycoplasma. Employment of species-specific primers within these infected cell lines revealed infection with M. hyorhinis (42.5%), M. fermentas (37.5%), M. arginini (37.5%), M. orale (12.5%) and A. laidlawii (7.5%). A number of the cultures were coinfected with 2 or 3 different species. Contaminated samples were treated with BM-Cyclin, Ciprofloxacin and mycoplasma removal agent (MRA). Mycoplasma eradication was subsequently checked by PCR following 2 weeks continuous culture of treated cells in antibiotic free culture medium. Mycoplasmal infections were eradicated in 100, 70 and 42% of infected cell lines when the samples were treated with BM-Cyclin, MRA and Ciprofloxacin, respectively. However, 12% (BM-Cyclin), 62.5% (MRA) and 82.5% (Ciprofloxacin) of mycoplasma regrowth was observed 4 months after the treatment. Notably, the risk of spontaneous culture death was 17.5, 12.5 and 0% for BM-Cyclin, MRA and Ciprofloxacin, respectively.     

Genes influencing spinal bone mineral density in inbred F344, LEW, COP, and DA rats

Previously, we identified the regions of chromosomes 10q12–q31 and 15p16–q21 harbor quantitative trait loci (QTLs) for lumbar volumetric bone mineral density (vBMD) in female F2 rats derived from Fischer 344 (F344) × Lewis (LEW) and Copenhagen 2331 (COP) × Dark Agouti (DA) crosses. The purpose of this study is to identify the candidate genes within these QTL regions contributing to the variation in lumbar vBMD. RNA was extracted from bone tissue of F344, LEW, COP, and DA rats. Microarray analysis was performed using Affymetrix Rat Genome 230 2.0 Arrays. Genes differentially expressed among the rat strains were then ranked based on the strength of the correlation with lumbar vBMD in F2 animals derived from these rats. Quantitative PCR (qPCR) analysis was performed to confirm the prioritized candidate genes. A total of 285 genes were differentially expressed among all strains of rats with a false discovery rate less than 10%. Among these genes, 18 candidate genes were prioritized based on their strong correlation (r ² > 0.90) with lumbar vBMD. Of these, 14 genes (Akap1, Asgr2, Esd, Fam101b, Irf1, Lcp1, Ltc4s, Mdp-1, Pdhb, Plxdc1, Rabep1, Rhot1, Slc2a4, Xpo4) were confirmed by qPCR. We identified several novel candidate genes influencing spinal vBMD in rats.     

Methylated bases in mycoplasmal DNA.

The DNAs of four Mycoplasma and one Acholeplasma species were found to contain methylated bases. All of the five species contained 6-methyladenine (m6Ade), the methylated base characteristic of prokaryotic DNA. The extent of methylation of adenine residues in the mycoplasmal DNA ranged from 0.2% in Mycoplasma capricolum to about 2% in Mycoplasma arginini and Mycoplasma hyorhinis with intermediate methylation values for Mycoplasma orale and Acholeplasma laidlawii DNAs. About 5.8% of the cytosine residues in M. hyorhinis DNA were methylated also. Analysis of cell culture DNA for the presence of m6Ade as a means for detection of contamination by mycoplasmas, and the phylogenetic implications of the finding of methylated bases in mycoplasmal DNAs are discussed.     

Polyclonal IgE increase after H9CI2 injections in BN and LEW rats: A genetic analysis

An autoimmune disease and a dramatic increase in total serum IgE concentration are observed in BN rats that are chronically injected with HgCl₂. In contrast, LEW rats do not develop the characteristic glomerulonephritis and are very low IgE responders. In this study, we examined the genetic control of total serum IgE increase after HgCl₂ injection in F₁ and F₂ hybrids, in both backcrosses between LEW and BN rats, and in LEW.1N congenic rats. Genetic analysis was performed using peak IgE concentrations expressed as log g/ml. A high IgE phenotype was found to be dominant. Eighty-five percent of F₂ variance was due to genetic factors (VG) while only 15% of this variance was caused by environmental factors (VE). From observations in F₂ hybrids and backcrosses, estimations of additive variance (VA) and dominance variance (VD) were made following three different methods. Genetic control by about four loci is demonstrated. One of these genes is RT1-linked. This gene contributes to 25% of the phenotypic difference observed between BN and LEW rats. No correlation was found between the peak total IgE level and autoimmune disease based on IgG deposition in spleen and/or kidney.     

Identification of a potent new pathogenic site in human retinal S-antigen which induces experimental autoimmune uveoretinitis in LEW rats

Experimental autoimmune uveoretinitis (EAU) is a T cell-mediated autoimmune disease of the eye which can be induced in LEW rats by immunization with either human or bovine S-antigen (S-Ag). In previous reports, two nonimmunodominant pathogenic sites were found using synthetic peptides corresponding to conserved sequences at amino acid residues 303-314 and 286-297 of the bovine sequence. In this report, a 20-residue synthetic peptide encompassing amino acids 343-362 located near the C-terminus was found to be highly immunopathogenic in LEW rats. The onset of EAU was observed at as early as 8 days when high doses of a peptide-encompassing residues 343-362 were used. EAU was elicited with as little as 0.5 microgram of peptide per animal. Smaller peptides from this region were also tested for uveitogenicity, further refining the site to 13 amino acids. Uveitogenic T cell lines were made to this site in two ways; first, by the in vitro selection of a bulk T cell line raised to human S-Ag with peptide 343-362. Second, by the in vitro selection of a peptide-specific line from an animal immunized with peptide 352-364, which corresponds to the minimal uveitogenic site. Both of these lines adoptively transferred EAU to LEW rats, further establishing the pathogenicity of this site. A proliferative site distinct from, but overlapping, the uveitogenic site was also found. The potent uveitopathogenicity of peptides from this region indicates that it is a major pathogenic site responsible for EAU induced in LEW rats by immunization with human S-Ag.     

Natural infections of aposymbiotic Cassiopea xamachana scyphistomae from environmental pools of Symbiodinium

The ability to acquire different types of the symbiotic dinoflagellate Symbiodinium (zooxanthellae) from the environment was investigated using aposymbiotic scyphistomae of the jellyfish Cassiopea xamachana. Non-symbiotic scyphistomae were placed on an offshore Florida patch reef and in Florida Bay during 3- and 5-day periods in March, and 5-day exposures in May, August and December of 2003. Scyphistomae were maintained in culture for several months, after which members of clades A, B, C and D Symbiodinium were detected in these hosts by denaturing gradient gel electrophoresis (DGGE) analyses. These findings contrast with naturally collected C. xamachana medusa from Florida Bay where all specimens possessed only Symbiodinium type A1. Furthermore, the polyps did not acquire the symbionts found in nearby cnidarian colonies, suggesting that a diverse pool of symbiont lineages exists in the environment. These results support previous laboratory studies where aposymbiotic hosts were initially non-selective and capable of acquiring many kinds of Symbiodinium. The specificity seen in adult hosts is likely a result of post-infection processes due to competitive exclusion or other mechanisms. A higher percentage of polyps became infected after 5 days of exposure, compared to 3 days, and no infections were observed in laboratory controls held in filtered seawater. Infections were lowest (50% at both sites) in March of 2003, when seawater temperatures were at their annual minima. Infection was 100% in scyphistomae exposed for 5 days during the months of May, August and December of 2003. These findings suggest that this host system, in addition to addressing questions of host-symbiont selectivity, can be employed to monitor and define the abundance and distribution of natural pools of Symbiodinium.     

Natural levels of fungal infections in grasshoppers in Northern Benin

The infection of grasshoppers by naturally occurring, entomopathogenic fungi was monitored at two sites in Malanville, northern Benin, Africa. Grasshoppers were collected and recorded from the sites between June and December 1992 and all of them, barring the first instars, were incubated in ventilated cages. At the first site, 1343 individuals of 35 grasshopper species were incubated, and at the second site, 857 individuals of 36 grasshopper species were incubated. Three hyphomycete fungi (Deuteromycotina: Hyphomycetes), Metarhizium flavoviride Gams and Rozsypal, Beauveria bassiana (Bals.) Vuillemin and Sorosporella sp. were found infecting grasshoppers. The average incidence of M. flavoviride infection was 2.9% and 1.8% at the two sites for all host species. M. flavoviride sporulated on most grasshopper cadavers within 10 days of collection. B. bassiana and Sorosporella sp. were only collected from one and five grasshopper individuals respectively. A significant difference was noted in the time to death of small grasshopper species infected with M. flavoviride compared to larger species. At one site, M. flavoviride infection was positively correlated with rainfall during the 10‐day period in which samples were taken.     

Clinical features of mycoplasmal pneumonia in adults

We have examined 221 cases of mycoplasmal pneumonia in adults during the past 17 years. During this time epidemic waves occurred every three to four years. The incidence of disease was highest in patients 20 to 30 years of age. The most common clinical features were cough, fever, sputum, and rales. The most characteristic feature was a persistent cough which lasted about three to four weeks. Roentgenographic examinations showed a variety of patterns, but the most consistent feature was a feathery shadow, appearing in the lower field of either or both of the lungs. Lung function tests showed peripheral airway impairment. Although roentgenographic examination provided useful information, it could not be used as a pathognomic feature of mycoplasmal pneumonia. Tetracyclines were most effective for eliminating clinical symptoms, whereas the macrolides provided the best response based on roentgenographic evaluations.