Hereditary hydrocephalus in laboratory-reared golden hamsters (Mesocricetus auratus)

A colony of golden hamsters had an ongoing problem with hydrocephalus. In an attempt to clear the colony of the problem, new breeders from another supplier had been purchased. At termination of a behavioral study, the brain was collected from 35 animals (four of which had died with hydrocephalus during the study) and was examined macroscopically and by light microscopy. Although no animals manifested obvious behavioral changes, 31 of 35 (88.6%, 13/15 males and 18/20 females in control and manipulated groups) had hydrocephalus. Twenty-five animals had macroscopically identifiable hydrocephalus, and six had hydrocephalus identified microscopically. Neither teratogenic concentrations of metals nor mycotoxins were detected in tissues or food, and sera from breeders tested negative for antibodies to Sendai virus, reovirus 3, and lymphocytic choriomeningitis virus. Trial matings of breeders expected to produce hydrocephalic offspring resulted in affected offspring, and mating of breeders expected to produce normal offspring resulted in normal or less-affected offspring. Hydrocephalus was confirmed retrospectively in some breeders. Hereditary hydrocephalus appears to be widespread in hamster stocks in Central Europe. Affected animals do not manifest signs of disease and usually die without obvious premonitory signs. Despite severe hydrocephalus, the animals can breed, and animal handlers do not identify motor deficits or abnormal behavioral activity. This entity is unlike the previously described, hereditary hydrocephalus of hamsters that is phenotypically identifiable and usually is lethal before they attain breeding age.

A technique to detect and to quantify fasciocutaneous blood vessels in small laboratory animals ex vivo

PURPOSE: A microangiographical technique is described, which allows visualization of small and capillary blood vessels and quantification of fasciocutaneous blood vessels by means of digital computer analysis in very small laboratory animals. MATERIALS AND METHODS: The left carotid artery of 20 nu/nu mice was cannulated (26 gauge) and a mixture of gelatin, bariumsulfate, and green ink was injected according to standardized protocol. Fasciocutaneous blood vessels were visualized by digital mammography and analyzed for vessel length and vessel surface area as standardized units [SU] by computer program. RESULTS: With the described microangiography method, fasciocutaneous blood vessels down to capillary size level can be clearly visualized. Regions of interest (ROIs) can be defined and the containing vascular network quantified. Comparable results may be obtained by calculating the microvascular area index (MAI) and the microvascular length index (MLI), related to the ROIs size. Identical ROIs showed a high reproducibility for measured [SU] < 0.01 +/- 0.0012%. CONCLUSION: Combining microsurgical techniques, pharmacological knowledge, and modern digital image technology, we were able to visualize small and capillary blood vessels even in small laboratory animals. By using our own computer analytical program, quantification of vessels was reliable, highly reproducible, and fast.

Validation of candidate smear microscopy quality indicators, extracted from tuberculosis laboratory registers

SETTING: Kinshasa Province, Democratic Republic of Congo. OBJECTIVE: To identify and validate register-based indicators of acid-fast bacilli (AFB) microscopy quality. DESIGN: Selection of laboratories based on reliability and variation in routine smear rechecking results. Calculation of relative sensitivity (RS) compared to recheckers and its correlation coefficient (R) with candidate indicators based on a fully probabilistic analysis incorporating vague prior information using WinBUGS. RESULTS: The proportion of positive follow-up smears correlated well (median R 0.81, 95% credibility interval [CI] 0.58-0.93), and the proportion of first smear-positive cases fairly (median R 0.70, 95% CI 0.38-0.89) with RS. The proportions of both positive suspect and low positive case smears showed poor correlations (median R 0.27 and -0.22, respectively, with ranges including zero). CONCLUSIONS: The proportion of positives in follow-up smears is the most promising indicator of AFB smear sensitivity, while the proportion of positive suspects may be more indicative of accessibility and suspect selection. Both can be obtained from simple reports, and should be used for internal and external monitoring and as guidance for supervision. As proportion of low positive suspect smears and consistency within case series are more difficult to interpret, they should be used only on-site by laboratory professionals. All indicators require more research to define their optimal range in various settings.