The inflammatory reaction surrounding Taenia solium larvae in pig muscle: ultrastructural and light microscopic observations

Summary An inflammatory reaction with the general characteristics of a chronic granuloma surrounding Taenia solium larvae in pig muscle is described. Larvae with an inflammatory capsule were obtained at slaughter from pigs 6–8 months-of-age and were processed for light and electron microscopy. Eosinophils (granulocytes with orange staining and peroxidase-positive granules) were found to be degranulated and in close contact with the parasite surface. Histiocytes, epithelioid cells, macrophages and lymphocytes were also evident, as well as large numbers of plasma cells in the outer areas of the well-circumscribed reaction. The parasites were ultrastructurally intact, with a normal tegument and only occasional changes in the microvesicles. The results are discussed with reference to parasite survival in the host.     

Dose-Dependent Cytotoxicity of Chlorinated Hydrocarbons in Isolated Rat Hepatocytes

Dose-Dependent Cytotoxicity of Chlorinated Hydrocarbons in IsolatedRat Hepatocytes. DAHLSTROM-KJNG, L., COUTURE, J., LAMOUREUX,C, VAILLANCOURT, T., AND PLAA, G. L. (1990). Fundam. Appl. Toxicol.14, 833–841. The aim was to determine if isolated suspendedhepatocytes could differentiate between the effects of fourchlorinated hydrocarbons that are hepatotoxic In vivo and fourthat are not. Membrane integrity was assessed by measuring alanineaminotransferase (ALT) release after 30- to 180-min incubationsin vitro. From the results, the chlorinated hydrocarbons fellinto three groups: tetrachloroethylene and 1,1,2,2-tetrachloroeth-anewere the most potent cytotoxicants; CCl₄, 1,1,2-trichloroethane,and trichloroethylene exhibited intermediate cytotoxicity; andlow cytotoxicity was observed with CHCl₃, 1,1,1 -trichlo-roethane,and 1,1-dichloroethylene. Cytotoxicity ranking correlated poorlywith the reported In vivo hepatotoxicity of these agents. Theeffect of adding SKF-525A on the cytotoxicity of tetrachloroethyleneand CCI4 was also assessed. In addition, hepatocytes from ratspretreated with 2,5-hexanedione were used to determine if theywere more susceptible to the effects of CHCl₃, CCl₄ or tetrachloroethylene.SKF-525A decreased the cytotoxicity of both CO, and tetrachloroethylene,whereas pretreatment with 2,5-hexanedione enhanced their effect.The effects of both SKF-525A and 2,5-hexanedione on CCl in vitroare consistent with In vivo findings. However, tetrachloroethyleneis not hepatotoxic In vivo, suggesting that SKF-525A might actby stabilizing plasma membranes rendering the hepatocyte moreresistant to lysis. Overall, the results cast doubts on theuse of ALT release from isolated hepatocytes as an appropriatein vitro model for assessing hepatotoxic properties of chlorinatedhydrocarbons.     

Preventing relapse in incarcerated drug users in Yunnan Province,China

Introduction and Aims. The mainstay of drug control in China is compulsory incarceration and detoxification, but relapse rates following release are very high. The aim of the study was to explore factors which would help prevent relapse in injecting drug users following release from detoxification centres. Design and Methods. Semi‐structured interviews were carried out at three compulsory detoxification centres in Derhong prefecture, Yunnan Province, which has the highest proportion of injecting drug users in China. Results. Interviews were completed with 235 men and 125 women aged between 15 and 64 years. They had been injecting heroine for between 3 months and 25 years; the median number of times of previous compulsory detoxification was four, with 11% having undergone this more than 10 times. All but six wanted to quit permanently, but almost all acknowledged that relapse on release was almost inevitable. The month immediately following release was identified as most vulnerable time for relapse. Respondents identified three measures which would help decrease the rate of relapse. First, the environment of the detoxification centres should emphasise support and counselling rather than punishment. Second, families should be provided with support to help the user immediately after release. Third, arrangements could be made to help those individuals who request relocation, to find work elsewhere away from accustomed drug‐using social networks. Discussion and Conclusions. While a combination of these measures could help in some way to reduce rates of relapse following detention, given the failure of the detoxification/detention regimes to reduce drug use, consideration must be given to other approaches.[Zhu WX, Dong JQ, Hesketh T. Preventing relapse in incarcerated drug users in Yunnan Province, China. Drug Alcohol Rev 2009]     

Coccidiosis: localization of lymphoblasts in the infected small intestine

Summary Peripheral blood lymphocytes of chickens and thoracic duct lymphocytes and mesenteric lymph node cells of rats, were labelled with ¹²⁵-deoxyuridine and injected intravenously into chickens or rats respectively. Sixteen to 18 h later the intestines of coccidia infected animals contained more radioactivity than those of uninfected controls. This result was obtained with cell suspensions from both infected and normal donors indicating that, as with nematode infected rodents, the increased homing of the cells to parasitised gut was not antigen specific. In chickens the stimulus which causes the increased homing of cells to the intestine was induced within hours of parasite inoculation. This reflects the rapid response of this host, previously described with other parameters, and which may be characteristic of birds.     

The effect of N-acetylcysteine on the in vitro growth of normal rabbit middle ear fibroblasts

In the present study the effect of N-acetylcysteine on the growth pattern and collagen synthesis of cultures of rabbit middle ear fibroblasts was determined. The growth pattern was evaluated by cell counting, measurements of the total content of cell protein and mitotic activity by incorporation of ³H-thymidine. Collagen synthesis was estimated by incorporation of ³H-proline. The results demonstrate a dose-dependent reduction in both normal cell proliferation and collagen production. Thus, N-acetylcysteine seems to possess properties desirable and useful in the treatment of secretory otitis media.     

Bacteria and endotoxin in middle ear fluid and the course of secretory otitis media

To determine the influence of bacteria and bacterial products on the course of secretory otitis media (SOM) following ventilation tube insertion we examined 68 middle ear effusions from 57 children with SOM. Swabs were taken for bacteriological examination and the content of endotoxin was measured. The children were followed up for one year and relapse of SOM was recorded. Bacteria were present in 38% of effusions and endotoxin was detectable in 96%. Relapse occurred in 26% of the patients and was related to the presence of bacteria in the original effusion (P 0.01). The concentration of endotoxin, however, did not correlate with the course of SOM. Keywords bacteria endotoxin secretory otitis media prognosis     

Alterations in tympanic membrane appearance and middle ear function in 11-year-old children with complete unilateral cleft lip and palate compared with healthy age-matched subjects

Forty-four 11-year-old children born with a complete unilateral cleft lip and palate were examined to determine the frequency and the extent of changes in the tympanic membrane and the middle ear function and compared with 16 healthy children of the same age. The incidence of hearing impairment, abnormal middle ear pressure, retraction of the pars flaccida and abnormal tympanic membrane appearance were 24, 44, 23 and 67% respectively among the patients while the same parameters in the control group were 0, 12.5, 6 and 12%. Previous grommet insertion in the patient group was statistically correlated to both tympanic membrane abnormality and abnormal middle ear pessure but, remarkably, no association was found between grommet insertion and hearing impairment. The poor middle ear function in the children with cleft lip and palate was probably a result of reduced Eustachian tube function.