Identification of antibiotic mycelia residues in cottonseed meal using Fourier transform near-infrared microspectroscopic imaging.

Near-infrared microscopy (NIRM) technology can analyze different components within a sample while also obtaining spatial information about the sample. No rapid detection methods are available for effectively identifying antibiotic mycelia residues (AMRs) in protein feeds materials to date. In this study, the feasibility of using NIRM to identify AMRs (oxytetracycline residue, streptomycin sulfate residue and clay colysin sulfate residue) mixed in cottonseed meals was studied. The samples were scanned by NIRM, then the spectra of images were analyzed by principal component analysis (PCA) to select characteristic bands for further identification with one-class partial least squares analysis (OCPLS). The results showed that: a) AMRs were effectively identified in cottonseed meal; b) screening characteristic bands and increasing the spectral number of the calibration set improved the identification results of the model; and c) the sensitivity, specificity, accuracy and class error of the method were 100%, 95.93%, 99.01% and 2.03%, respectively.

Laboratory diagnosis of malaria in the North West Region of Cameroon: analysis of limitations.

BACKGROUND: Malaria is still rife and perennial in Cameroon despite remarkable progress in controlling the disease. About 95% of the country is malaria endemic. Prompt and accurate diagnosis of malaria may lead to improved patient care and reduced morbidity. This paper analyses limitations in malaria diagnosis in the North West Region of Cameroon and opportunities for improvement. METHODS: The sample units were 40 laboratories in governmental health facilities (GHFs) selected by cluster (Health Districts) and stratified sampling. The three categories of GHFs in the Region - Hospitals, District Medical Centres (Centre Médical d'Arrondissement [CMAs]) and Integrated Health Centres (IHCs) - were strata in the sample. With pre-tested interviewer-administered structured questionnaires and visits to laboratories, mechanical and optical components of microscopes and malaria diagnostic techniques were studied systematically and in detail. RESULTS: The main finding was that locally prepared Giemsa-stained malaria smears were of unusable quality in 52 and 46% of GHFs for thick and thin smears respectively. Some loss of quality was observed in laboratories with good and moderate quality smears. CONCLUSION: The quality of malaria diagnosis was not optimal and GHFs did not have sufficient tools and resources to overcome loss of quality. Nonetheless, limitations in malaria diagnosis in the Region can be corrected.

Evaluation of human spermatozoa in cervical mucus: comparison of different microscopic and extraction techniques.

This study was designed to describe an accurate and consistent microscopic technique for the assessment of sperm number and motility in sperm-cervical mucus samples, such as those of postcoital tests (PCTs), and to identify a suitable method to extract functional spermatozoa from cervical mucus (CM). Sperm-CM preparations containing various sperm concentrations were counted using three different microscopic illuminations. The dark field-Makler technique was compared with the more classical bright field-slide technique currently used by our clinicians. Several sperm extraction techniques were applied first to bovine (BCM) and then to human (HCM) cervical mucus. Dark field microscopic illumination provided accurate, fast, and easy sperm identification. Counting variability was significantly greater with bright field-slide than with dard field-Makler, while sperm motility was always higher with this latter methodology. A high degree of agreement (intraclass correlation coefficient = 0.965) among three raters, i.e., low interobserver variability, was obtained only with dark field-Makler. Extraction procedures based on "swim-out," Percoll, trypsin, an enzyme cocktail, and mercaptoethanol resulted in small sperm yields in BCM. Mercaptoethanol and trypsin also showed poor sperm recovery in HCM. Among the protocols with the largest yields, the mechanical technique had the largest amount of residual CM, and bromelain reduced sperm motility. The extraction with dithiothreitol (DTT) showed the best results with a mean sperm recovery of 76% and enhanced sperm motility. Sperm viability as well as spontaneous and induced acrosome reaction were conserved in all techniques. In conclusion, use of the dark field-Makler counting technique in combination with DTT extraction of spermatozoa from CM samples, such as those of PCTs, would allow accurate and functional assessment of spermatozoa for preliminary contraceptive efficacy or infertility evaluation.