Statistical design for health monitoring in laboratory animal facilities using sentinel animals.

Regular health monitoring is crucial in laboratory animal facilities to determine the presence or absence of specific pathogens. One common approach to monitoring involves the use of sentinel animals, which are periodically exposed to biological material from the cages being monitored. At a certain point, some of these sentinel animals are tested for pathogens. This article discusses designing an effective sampling scheme to meet desired quality standards. It addresses questions such as the number of sentinel animals required, the frequency of sampling biological material, the selection of cages based on facility set-up, and the optimal frequency and quantity of sentinel animal tests. While existing design formulas are available for simple random sampling, no quantitative recommendation exists for using sentinel animals to the best of our knowledge. We propose a Monte Carlo simulation-based approach in this article to address this. Our algorithm has been implemented in a publicly accessible web page at http://nolan.cnb.csic.es/sentinelcagesmanager.

Characterization dataset of oil palm empty fruit bunch (OPEFB) fibers - Natural reinforcement/filler for materials development.

Natural fibers used as reinforcements or fillers for materials development greatly affect properties and performance of end-use applications. As a consequence of conditioning processes such as grinding and sieving, average fiber length varies significantly. It is thus necessary to estimate the length as statistical data distribution rather than a single mean value. This approach implies length measurement of a significant number of fibers; however, a very high number of data points requires not only long-time frames but also significative amount of work. To address these issues, this article details a facile methodology to measure the length of a large number of natural fibers of oil palm empty fruit bunch (OPEFB) together with a statistical analysis to verify the correspondence between theoretical distributions and experimental data. Moreover, further information related to spectrophotometric, physico-chemical, mechanical, thermal, and morphological characteristics of OPEFB fibers coming from oil palm cultivation in Ecuador are presented. The data will contribute to comprehensively and rigorously describe the overall effects of natural fiber lengths on material properties.

Identification of an aromatase haplotype that is associated with gene expression and postmenopausal osteoporosis.

CONTEXT: Osteoporosis has a significant genetic component. The aromatase-dependent conversion of androgenic precursors is the main source of estrogens in postmenopausal women. OBJECTIVE: The objective of the investigation was to study the relationship of a set of single nucleotide polymorphisms (SNPs) of the aromatase gene with osteoporosis and determine their functional influence on gene transcription. DESIGN, PARTICIPANTS, AND METHODS: This was a case-control study including 135 women with vertebral fractures due to postmenopausal osteoporosis and 312 controls. Alleles at four SNPs situated between exons I.2 and 3 were determined by Taqman assays. Total aromatase RNA and differential allelic-specific expression were studied by RT-real time PCR in adipose tissue samples taken from 50 individuals. RESULTS: The SNPs studied were in strong linkage disequilibrium. A common haplotype, present in about half of the population, was identified as being associated with an increased risk of fractures (odds ratio 1.8, 95% confidence interval 1.2-2.8, P = 0.006). There was evidence of differential allelic expression. In heterozygous individuals, transcripts bearing T alleles at rs700518 SNP (which were included in the risk haplotype) were less abundant than those with the alternative C alleles (P < 0.001). Total aromatase expression was four times lower in fat samples from individuals who were homozygotes for the unfavorable alleles than in the opposite homozygotes (P = 0.007). CONCLUSIONS: A common haplotype of aromatase associated with gene expression is also associated with the risk of osteoporotic vertebral fractures in postmenopausal women. These data are in line with the hypothesis that the aromatase-dependent synthesis of estrogens plays an important role in bone homeostasis in postmenopausal women.

Surgical treatment of persistent hyperinsulinemic hypoglycemia (PHH) (insulinoma and nesidioblastosis).

BACKGROUND: The persistent hyperinsulinemic hypoglycemia is characterized by clinical symptoms that occur when the blood glucose levels drop below the normal range. Two pathological situations cause this clinical problem: The presence of a tumor of the pancreas secreting excessive amounts of insulin, known as insulinoma, and congenital beta-cell hyperplasia in the pancreas in children and noninsulinoma pancreatogenic hypoglycemia syndrome in adults. PATIENTS AND METHODS: Clinical characteristic and surgical outcome of a group of 20 patients operated on for this hypoglycemic syndrome; 18 for insulinoma and two for nesidioblastosis in children was studied. RESULTS: eight of the insulinomas were in the head of the pancreas, two in the body, and the remaining eight in the tail. The surgical technique was enucleation in nine cases, local resection in one case because of suspicious malignancy, and distal pancreatectomy in eight cases. Both children with nesidioblastosis underwent 85% pancreatectomy with splenic preservation. There was no mortality in the study, but three patients developed a low-volume pancreatic fistula after head enucleation. CONCLUSIONS: Negative results in diagnostic localization together with the small size of the insulinoma represent a poor combination for successful surgery. The intraoperative ultrasonography is the method of choice for the identification of the tumor, as it is able to identify nonpalpable lesions.

Refinement of intrathymic injection in mice.

Direct intrathymic injection is a common procedure used in several types of experimental protocols in the mouse. Currently available approaches involve major surgical procedures that expose the thoracic cavity, resulting in an increased risk of poor recovery and postsurgical complications. The authors sought to refine this surgery to reduce animal pain and distress without compromising overall efficiency of the technique. Using a minimally invasive method that does not expose the thoracic cavity, the authors gave accurately placed intrathymic injections, as confirmed by analyses with a reporter dye. They describe this new approach for intrathymic injection in mice that reduces complications associated with lengthy periods of anesthesia and thoracic cavity exposure.

Genetically modified mouse health reporting: a need for global standardization.

The distribution of GM mice between facilities has raised new problems because of variable microbiological quality. One of the most important management issues concerns the methods of reporting laboratory animal health surveillance results. The authors evaluated the format and content of 380 health reports of mice received from 55 institutions in Europe and North America. Their results suggest that a standardized rodent health form would facilitate the management of laboratory mouse distribution and infection control.

Perforated peptic ulcer treated by simple closure and Helicobacter pylori eradication.

Simple closure followed by Helicobacter pylori (Hp) eradication has become the most used procedure in perforated ulcer treatment. However, its efficacy and safety are still to be determined. To assess recurrence and re-perforation rates, and as a secondary objective, to analyze Hp infection rates in perforated ulcer patients and controls, we conducted a prospective study. Ninety-two consecutive patients (ages: 19-96 years) were operated on between 1996 and 2002, and treated by simple closure followed by Hp eradication and NSAID avoidance. The data were prospectively collected in a database. Hp infection was diagnosed in 68 patients (73.9%). Thirty-four patients (37%) consumed nonsteroidal anti-inflammatory drugs (NSAIDs), and 23 (25%) had both Hp infection and NSAID antecedents. The perforation was gastric in 4 cases and pre-pyloric, pyloric or duodenal in 88. There were postoperative complications in 24 patients (26%) and 4 patients died (4.3%). Hp eradication was shown in 46 patients. There was clinical ulcer recurrence in 4 (4.3%); in 3 of them recurrence manifested as re-perforation, all in gastric locations. Overall relapse and re-perforation 1-year crude rates were 6.1% and 4.1%, respectively. Crude rates for non-gastric ulcer recurrence were 0 at 1 year and 2.6% at 2 years and for non-gastric ulcer re-perforation rates were 0 at 1 and 2 years. This therapeutic strategy is associated with a low rate of recurrence and no re-perforations in case of duodenal, pyloric, or pre-pyloric perforated ulcers, but it is not acceptable for perforated gastric ulcers.