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We observed an unexpectedly strong association of three different endogenous aldehydes and noted that the association could be explained by multiple reactions in which oxidative stress increased the formation of endogenous aldehydes and endogenous aldehydes increased oxidative stress. These interactions make it reasonable to assess multiple exposures to endogenous oxidative and aldehyde stress with less specific measures such as advanced glycation end-products or protein carbonyls.

Bartonella henselae is the main agent of cat scratch disease in humans and domestic cats are the main reservoir of this bacterium. We conducted a serosurvey to investigate the role of American wild felids as a potential reservoir of Bartonella species. A total of 479 samples (439 serum samples and 40 Nobuto strips) collected between 1984 and 1999 from pumas (Felis concolor) and 91 samples (58 serum samples and 33 Nobuto strips) collected from bobcats (Lynx rufus) in North America, Central America and South America were screened for B. henselae antibodies. The overall prevalence of B. henselae antibodies was respectively 19.4% in pumas and 23.1% in bobcats, with regional variations. In the USA, pumas from the southwestern states were more likely to be seropositive for B. henselae (prevalence ratio (PR) = 2.82, 95% confidence interval (CI) = 1.55, 5.11) than pumas from the Northwest and Mountain states. Similarly, adults were more likely to be B. henselae seropositive than juveniles and kittens (PR = 1.77, 95% CI = 1.07, 2.93). Adult pumas were more likely to have higher B. henselae antibody titers than juveniles and kittens (p = 0.026). B. henselae antibody prevalence was 22.4% (19/85) in bobcats from the USA and 33.3% (2/6) in the Mexican bobcats. In the USA, antibody prevalence varied depending on the geographical origin of the bobcats. In California, the highest prevalence was in bobcats from the coastal range (37.5%). These results suggest a potential role of wild felids in the epidemiological cycle of Bartonella henselae or closely related Bartonella species.

The roughness and surface microstructure during setting of five commercially available amalgam alloys were evaluated.

An anonymized point-prevalence survey of methicillin-resistant Staphylococcus aureus (MRSA) carriage was conducted amongst a stratified random sample of nursing home residents in Birmingham, UK, during 1994. Microbiological sampling from noses, fingers and the environment was undertaken. Information about potential risk factors for the acquisition of MRSA was gathered. MRSA was isolated from cultures of the nose or fingers of 33 of the 191 residents who took part in the study (17%) but only 1 of the 33 positive residents had a clinical infection. Although just 10 of the 87 environmental samples were MRSA positive, there was some environmental contamination in most homes. Risk factors for MRSA carriage were hospital admission within the last year (relative prevalence 2·09, 95% CI 1·13–3·88; P < 0·05) and surgical procedures within the last year (relative prevalence 4·02, 95% CI 2·18–7·43; P = 0·002). Phage-typing of the strains revealed similarities with those circulating in Birmingham hospitals. These findings suggest that the prevalence of MRSA in nursing homes in Birmingham was high, and that the strains may have originated in hospitals.

In 1997, ticks removed from humans and received alive by the Tick-Borne Disease Laboratory of the U.S. Army Center for Health Promotion and Preventive Medicine (USACHPPM) were tested for pathogens by polymerase chain reaction (PCR). Thirty-three of 222 (15%) Amblyomma americanum (L.) DNAs produced amplicons of the expected size of Ehrlichia chaffeensis Anderson, Dawson & Wilson and 26/222 (12%) produced amplicons indicating Borrelia burgdorferi Johnson, Schmid, Hyde, Steigalt & Brenner. Five (2%) appeared to be co-infected with both organisms. Thirteen of 308 (4%) Dermacentor variabilis (Say) were PCR-positive for spotted fever group rickettsiae. Restriction fragment-length polymorphism analysis indicated all were Rickettsia montana. One hundred twenty-seven D. variabilis from Monroe County, WI, were tested for B. burgdorferi and 14 (11%) were positive. Five of 24 (21%) Ixodes scapularis Say were positive for B. burgdorferi and one (2%) was positive for the agent of human granulocytic ehrlichiosis. Different species of ticks transmit different pathogens, and most tick-borne diseases have similar early symptoms, therefore knowing the species and infection status of the tick enhances the physician’s ability to consider tick-borne agents as a potential cause of disease and recommend appropriate therapy. Ongoing surveillance of the vector species of human diseases provides an additional estimate of human encounters with infected ticks, and testing ticks removed from humans may increase our knowledge of the vector status of tick species for transmitting tick-borne pathogens.

Human monocytic ehrlichiosis (HME) is a sometimes fatal, emerging tick-borne disease caused by the bacterium Ehrlichia chaffeensis. It is frequently misdiagnosed because its symptoms mimic those of the flu. Current evidence indicates that Amblyomma americanum (L.), the lone star tick, is the major vector of HME. To determine if E. chaffeensis is present in ticks at Aberdeen Proving Ground, MD, questing A. americanum ticks were collected from 33 sites. Nucleic acid was extracted from 34 adult and 81 nymphal pools. Sequences diagnostic for E. chaffeensis from three different loci (16S rRNA, 120-kDa protein, and a variable-length polymerase chain reaction [PCR] target, or VLPT) were targeted for amplification by the PCR. Fifty-two percent of the collection sites yielded pools infected with E. chaffeensis, confirming the presence and widespread distribution of E. chaffeensis at Aberdeen Proving Ground. Analysis with the both the 120-kDa protein primers and the VLPT primers showed that genetic variance exists. A novel combination of variance for the two loci was detected in two tick pools. The pathogenic implications of genetic variation in E. chaffeensis are as yet unknown.

Laboratory assays were done to quantify proportions of phenotypes in laboratory colonies resistant to several classes of insecticides in the cotton aphid, Aphis gossypii Glover. Resistance to a carbamate (aldicarb), an organochlorine (endosulfan), an organophosphate (chlorpyrifos), and a pyrethroid (bifenthrin) was documented. Significant declines in numbers of individuals resistant to bifenthrin and endosulfan but not for chlorpyrifos occurred during a 5-mo interval after the first bioassays. Resistance ratios between clonal susceptible and resistant cotton aphid colonies for chlorpyrifos indicated a significant 4-fold difference in LC50 estimates for the two colonies. Spectrophotometric analyses indicated Significantly higher carboxylesterase activity in resistant aphids compared with susceptible aphids. Results from isoelectric polyacrylamide focusing gel techniques also showed differences in carboxylesterases, both in differences in banding patterns and in expression of comigrating bands.