Contemporary topics in laboratory animal science最新文献

There are many reasons wounds are managed as open wounds rather than by primary closure. Indications include gross contamination, infection, and skin loss leading to insufficient adjacent tissue for wound closure. The most common method of managing an open wound is with wet-to-dry dressings. Wet-to-dry dressings provide mechanical debridement and promote the movement of viscous exudates away from the wound. Wet-to-dry bandages ideally are changed every 12 to 24 h. For nonhuman primates, it is desirable to develop wound management techniques that limit animal handling for bandage changes and thus the frequency of sedation. Anecdotal reports on the use of honey to treat wounds date back to 2000 B.C. Recently, scientific inquiries have found merit to these reports. Honey accelerates healing because of its direct effects on tissue and antibacterial properties. In addition, dressings with honey can be changed relatively infrequently. Honey decreases inflammatory edema, hastens sloughing of devitalized tissue, attracts macrophages which cleanse the wound, provides a local cellular energy source, and protectively covers the wound. A high osmolarity, acidity, and hydrogen peroxide content confer honey with antibacterial properties. Here we describe the use of honey to manage a bite wound in a stumptail macaque (Macaca arctoides). The wound healed rapidly: after 2 weeks of treatment, there was markedly less exudate and no necrotic tissue. This report describes how honey may be helpful in the management of open wounds in nonhuman primates by minimizing the need for sedation for bandage changes.

The anogenital distance (AGD) is sexually dimorphic in Mus musculus domesticus, with the male AGD approximately twice as long as that in female mice. Among female mice, the AGD varies as a function of prenatal androgen exposure. The anogenital distance index (AGDI) has been developed to serve as an indicator of prior androgen exposure due to intrauterine position (IUP). Concerns have been raised that the AGDI may not be an appropriate indicator of female IUP in mice. To further refine the AGDI, we have applied some commonly used and suggested transformations to the original data set of female CD-1 mice of known IUP, weaning body mass, and AGD. Our analysis suggests that the residual log transformation and untransformed body mass AGDIs are the most accurate means to predict the IUP of the pup. However, the IUP is only one mechanism by which a fetus may be exposed to hormonal variations in utero. Additional analyses revealed that the AGDI is influenced not only by the IUP of the female fetus but also by the identity of the dam (indicative of maternal influences) and the number of male fetuses found in the particular uterine horn. Therefore, the AGDI is not strictly a predictor of female IUP but of the intrauterine androgen environment in mice.

The following case report describes a complication after accidental overinflation of the lungs in an anesthetized rabbit. After anesthetic induction, endotracheal intubation, and preparation for surgery, the rabbit's arterial oxygen saturation dropped. Positive-pressure ventilation was administered using manual compression on the reservoir bag. The rabbit's condition rapidly deteriorated, and emergency treatment including oxygen, anesthetic reversal, and thoracocentesis was initiated. The rabbit failed to respond to therapy. A focal, acute, alveolar, vascular, and pleural rupture of the right caudal medial lung lobe with secondary pulmonary tension pneumothorax and atelectasis was identified postmortem. The etiology and pathophysiology of the clinical signs are reviewed. Pulmonary pressure overload after manual or assisted ventilation and subsequent stress failure occurs when pulmonary pressures approach 40 mm Hg. Close attention to the animal's size, tidal volume, and potentially altered pulmonary elasticity from pre-existing lung disease may help reduce the incidence of failure. Successful therapy of iatrogenic pneumothorax may necessitate both medical and surgical intervention.

There have been only a few case reports of heart disease in monkeys. In the case we present, a cardiac murmur was auscultated in a 26-month-old male cynomolgus monkey during a routine physical examination. Echocardiography of this monkey revealed features indicating blood flow from the left ventricle to the right ventricle through the ventricular septum. These findings clarified that the animal had a muscular interventricular septal defect.

In experimental decerebration of mammals, the cerebral cortex and thalamus are surgically or otherwise inactivated under traditional (pharmacologic) general anesthesia. Once the effects of the pharmacologic anesthesia have dissipated, the animal remains alive, but there is neither pain sensation nor consciousness. Because the Animal Welfare Act and its regulations recognize drugs as the only means to alleviate pain, it is unclear whether a decerebrate animal should be placed in U.S. Department of Agriculture (USDA) pain and distress category D (pain or distress alleviated by drugs) or E (unalleviated pain or distress). We present a rationale for including decerebrate animals in USDA category D. We also provide a general review of decerebration and suggestions for institutional animal care and use committees having to evaluate decerebration protocols.

A recent article in Contemporary Topics in Laboratory Animal Science by Pullium and colleagues expressed the opinion that because no other source could be found for a parvoviral contamination detected in sentinel mice prior to deployment, the infection apparently came from the unspecified vendor, even though no antibodies were ever detected in mice within 3 weeks of arrival. As this opinion may be shared by others and expresses some of the deep frustration in trying to detect the source of parvoviral infection in facilities using cage-level bioexclusion housing, Charles River Laboratories (CRL) feels it important to contribute to scientific dialogue by claiming to be the unnamed vendor in the Pullium article and discussing why a parvoviral contamination in a CRL barrier room would be detected rapidly. We show that viral infections in CRL barrier rooms rapidly reach high prevalence and that such contaminations historically have been detected quickly, and we describe why we feel enhancements in current monitoring methods provide for even more rapid detection of parvoviruses. Furthermore, we present substantial evidence that the barrier rooms that served as the source of the customer-suspect sentinel mice remain free of all parvoviruses, in light of monitoring of hundreds of mice by all available techniques. Therefore, although an initial list of all possible sources of contamination prudently should include vendors, the evidence is overwhelming that this vendor was not the source of the parvoviral contamination discussed in the Pullium paper.

A 23-year-old female rhesus macaque presented with a 2.5-cm diameter, firm, moveable, lobulated subcutaneous mass associated with a supranummary teat on the right side of the chest. This animal was a retired breeder, currently in an aging study. No exogenous hormone treatments were noted in the animal's history. Chest radiographs were within normal limits. Blood screens showed no noteworthy variations from normal. Needle aspirate cytology showed clusters of neoplastic cells. Grossly the mass was well circumscribed, firm, and homogeneously tan, with a glandular appearance. Differential diagnoses included sebaceous or mammary adenoma, carcinoma in situ, and lobular or ductular carcinoma. Histopathology was consistent with a mammary ductal carcinoma with comedo pattern. Subsequent needle aspirate cytology from an adjacent right axillary lymph node showed tumor cells with a few lymphoid cells, interpreted as lymphatic spread. Chest radiographs 2 and 6 weeks postbiopsy showed no evidence of pulmonary metastasis. After 1 year, there was no marked change on chest radiographs, but a small cluster of new nodules was palpable in the right axillary region. Histopathology of an excisional biopsy of the new nodules indicated tumor growth subjacent to regional lymph nodes. Further treatment was not performed and the animal remained clinically normal five years after the initial diagnosis. Spontaneous mammary neoplasia is a major concern in human medicine, yet it rarely has been reported to occur in nonhuman primates. This case is important in documenting an additional case of spontaneous mammary tumor development.

Although Helicobacter spp. have been viewed as bacteria with low pathogenicity, many investigators have shown that these low-grade pathogens have the potential to become a severe threat in immunocompromised, inbred, and transgenic animals. Therefore the presence of Helicobacter spp. in experimental animals is considered to be an unacceptable variable. In this study a formulation of medicated feed was designed and tested in an attempt to eradicate Helicobacter spp. from an infected rat breeding colony. Two feeding protocols were used: 1) treating Helicobacter-infected pregnant dams to produce clean offspring and 2) treating infected adult animals long enough to eliminate the organisms. Bacterial DNA was extracted from feces and amplified using primers that recognized the Helicobacter spp.-specific region of the 16S rRNA gene. Fecal samples from the weanlings from protocol 1 tested negative for Helicobacter spp. at 1 week before and 2 and 12 weeks after weaning. Infected adult rats from protocol 2 tested negative after three cycles of 2 weeks on and 2 weeks off the medicated feed. Animals from both protocols have remained Helicobacter-free for 8 months.

Interdigital cysts are chronic inflammatory lesions that can be found in dogs. In order to better understand their etiology, we completed a retrospective analysis of epidemiologic factors by using the clinical records from 743 research Beagles at our research site. Factors examined included age, gender, weight, body condition score, location of the cyst, and type of cage flooring. Statistical analysis revealed that age, body condition score, and type of flooring were all significant factors in the occurrence of interdigital cysts. The epidemiological evidence supports the hypothesis that interdigital dermatitis is the inciting cause of interdigital cysts.

A colony of mutant mice with sickle cell anemia was infested with the fur mites Myocoptes musculinus and Myobia musculi. Pups of sickle-cell phenotype obtained by cesarean section prior to natural birth were of such poor vigor that none survived the combined insults of delivery by hysterectomy and cross-fostering. Consequently, surgical rederivation, the most reliable means of mite eradication, was not an option. Because furless mice are not susceptible to mite infestation and because neonates putatively remain free of mites until 4 to 5 days after birth, pups born by natural delivery were cross-fostered within 0 to 36 h to outbred lactating females treated once with ivermectin (2 mg/kg topically) at the time of transfer and housed in filter-top cages. Cross-fostering in conjunction with topical ivermectin administered to weaned mice one or more times at approximate 9-day intervals beginning on the day of weaning was successful in reliably eradicating mites. In addition, the 58% postnatal survivability of pups cross-fostered to dams given ivermectin was equivalent to that of natural-born pups that were reared by their untreated biological mothers.