Fear-conditioning testing paradigms have been used to study differences in memory formation between inbred mouse strains, including numerous mouse models of human diseases. In this study, we characterized the conditioned fear memory of 3 inbred strains: C57BL/6NCrl, 129S2/SvPasCrl, and FVB/NCrl, obtained from Charles River Laboratories. We used 2 training paradigms: delay conditioning, in which an unconditional stimulus coterminates with the presentation of a conditional stimulus, and trace conditioning, in which the conditional and unconditional stimuli are separated by a trace interval. In each paradigm, we evaluated the recent (3 d) and remote (25 d) memory of the mice by using a longitudinal design. Our results showed that both C57BL/6NCrl and 129S2/SvPasCrl mice developed strong and long-lasting context and tone memories in both paradigms, but FVB/NCrl mice showed a weaker but nevertheless consistent tone memory after delay training. Tone memory in the FVB strain was stronger in male than female mice. The remote tone memory of 129S2/SvPasCrl mice diminished after delay training but was stable and stronger than that of C57BL/6NCrl mice after trace training. In conclusion, both C57BL/6NCrl and 129S2/SvPasCrl mice showed reliable and long-lasting fear memory after delay or trace training, with 129 mice showing particularly strong tone memory after trace conditioning. The FVB/NCrl strain, especially male mice, showed reliable tone fear memory after delay training. Our findings confirm that both C57BL/6NCrl and 129S2/SvPasCrl mice develop strong context and tone memory in delay and trace fear-conditioning paradigms.

Many people in our society experience curtailment and disruption of sleep due to work responsibilities, care-giving, or life style choice. Delineating the health effect of acute and chronic disruptions in sleep is essential to raising awareness of and creating interventions to manage these prevalent concerns. To provide a platform for studying the health impact and underlying pathophysiologic mechanisms associated with inadequate sleep, we developed and characterized an approach to creating chronic disruption of sleep in laboratory mice. We used this method to evaluate how 3 durations of sleep fragmentation (SF) affect sleep recuperation and blood and lung analyte concentrations in male C57BL/6J mice. Mice housed in environmentally controlled chambers were exposed to automated SF for periods of 6, 12, or 24 h or for 12 h daily during the light (somnolent) phase for 4 sequential days. Sleep time, slow-wave amplitude, or bout lengths were significantly higher when uninterrupted sleep was permitted after each of the 3 SF durations. However, mice did not recover all of the lost slow-wave sleep during the subsequent 12- to 24-h period and maintained a net loss of sleep. Light-phase SF was associated with significant changes in serum and lung levels of some inflammatory substances, but these changes were not consistent or sustained. The data indicate that acute light-phase SF can result in a sustained sleep debt in mice and may disrupt the inflammatory steady-state in serum and lung.

Biofilm formation represents a unique mechanism by which Staphylococcus aureus and other microorganisms avoid antimicrobial clearance and establish chronic infections. Treatment of these infections can be challenging, because the bacteria in the biofilm state are often resistant to therapies that are effective against planktonic bacteria of the same species. Effective animal models for the study of biofilm infections and novel therapeutics are needed. In addition, there is substantial interest in the use of noninvasive, in vivo data collection techniques to decrease the animal numbers required for the execution of infectious disease studies. To ad- dress these needs, we evaluated 3 murine models of implant-associated biofilm infection by using in vivo bioluminescent imaging techniques. The goal of these studies was to identify the model that was most amenable to development of sustained infections that could be imaged repeatedly in vivo by using bioluminescent technology. We found that the subcutaneous mesh and tibial intramedullary pin models both maintained consistent levels of bioluminescence for as long as 35 d after infection, with no implant loss experienced in either model. In contrast, a subcutaneous catheter model demonstrated significant incidence of incisional ab- scessation and implant loss by day 20 after infection. The correlation of bioluminescent measurements and bacterial enumeration was strongest with the subcutaneous mesh model. Among the 3 models we evaluated, the subcutaneous mesh model is the most appropriate animal model for prolonged study of biofilm infections by using bioluminescent imaging.

To study spontaneous intraocular hemorrhage in rats during postnatal ocular development and to elucidate the underlying mechanism, postnatal ocular development in the albino Wistar Hannover (WH) and Sprague–Dawley (SpD) and pigmented Long–Evans (LE) strains was analyzed. Pups (n = 2 to 5) from each strain were euthanized daily on postnatal days (PND) 0 through 21 and their eyes examined macroscopically and histologically; similar analyses were performed in 26 to 39 additional WH pups daily from PND 7 to 14. At necropsy, ring-shaped red regions and red spots were present in the eyes of WH and SpD rats. These lesions were attributed histologically to hemorrhage of the tunica vasculosa lentis or of the retina, choroid, and hyaloid artery, respectively. Similar intraocular hemorrhages occurred in LE rats, although the macroscopic alterations found in WH and SpD rats were not present in this strain. Among the 3 strains evaluated, the incidence of the intraocular hemorrhage was highest in WH rats. We here showed that intraocular hemorrhage occurs spontaneously during normal ocular development in rats regardless of the strain; however, the region, degree, and incidence of intraocular hemorrhage differ among strains. Hemorrhage in the tunica vasculosa lentis and hyaloid artery may result from the leakage of erythrocytes from the temporary vasculature of these tissues during regression. The mechanisms underlying hemorrhage in the retina and choroid remain unclear. To our knowledge, this report is the first to describe the spontaneous intraocular hemorrhage that occurs during postnatal ocular development in rats.

This study characterizes the effect of an excess-calorie, high-fat, high-cholesterol, high-fructose diet on metabolic parameters and reproductive function in female Ossabaw minipigs. Cycling sows were fed a hypercaloric, high-fat, high-cholesterol, and high-fructose diet (obese, n = 4) or a control diet (control, n = 5) for 13 mo. During the final 4 mo, ovarian ultrasonography was done, blood was collected, and weights and measures were taken. Pigs then underwent ovarian stimulation. Cycle length and androstenedione, total testosterone, progesterone, estradiol, follicle-stimulating hormone, luteinizing hormone, insulin, fructosamine, lipid, and glucose levels were measured. In addition, adipose tissue aromatase gene expression was assessed. As compared with control pigs, obese pigs were hyperglycemic and hyperinsulinemic; had elevated total cholesterol, triglyceride, and leptin levels, and demonstrated abdominal adiposity. Visceral adipose tissue of obese pigs, as compared with control pigs, showed increased aromatase gene expression. Obese pigs had longer estrous cycles, higher serum androstenedione, and higher luteal phase serum luteinizing hormone, compared with control pigs. During the luteal phase, obese pigs had more medium, ovulatory, and cystic ovarian follicles, whereas control pigs had more small ovarian follicles. When fed an excess-calorie, high-fat, high-cholesterol, high-fructose diet, female Ossabaw minipigs develop obesity, metabolic syndrome, and abnormal reproductive function. This animal model may be applicable to studies of the effects of obesity on fertility in women.

Appropriate animal models for intradermal vaccine delivery are scarce. Given the high similarity of their skin anatomy to that of humans, minipigs may be a suitable model for dermal vaccine delivery. Here we describe the immunization of Göttingen minipigs by using intradermal and intramuscular delivery of hepatitis B surface antigen (HBsAg). Intradermal vaccine delivery by needle and syringe and by needle-free jet injection induced humoral antiHBsAg responses. Priming immunization by using the disposable syringe jet injector (DSJI) resulted in a higher antibody titer than did conventional intradermal immunization and a titer comparable to that after intramuscular vaccination with HBsAg and Al(OH)₃ adjuvant. This study highlights the utility of the minipig model in vaccine studies assessing the efficacy of conventional and novel methods of dermal delivery. Moreover, we include suggestions regarding working with minipigs during dermal vaccine delivery studies, thereby fostering future work in this area of vaccinology.

Female vervet monkeys (Chlorocebus aethiops sabaeus) are used as an experimental model for chronic diseases relevant to women's health. However, reproductive senescence (menopause) has not yet been characterized for vervet monkeys. Here we describe the histologic, hormonal, and menstrual markers of reproductive senescence in vervet monkeys from the Wake Forest Vervet Research Colony. Ovaries from monkeys (age, 0 to 27 y) were serially sectioned (5 μm), stained, and photographed. In every 100th section, the numbers of primordial, primary, and secondary follicles were determined, and triplicate measurements were used to calculate mean numbers of follicles per ovary. Antimüllerian hormone (AMH), follicle stimulating hormone, and menstrual cycle length were measured in additional monkeys. Primordial follicles and AMH decreased significantly with age, and significant correlations between numbers of primordial and primary follicles and between numbers of primary and secondary follicles were noted. Histologic evaluation revealed that ovaries from 4 aged monkeys (older than 23 y) were senescent. One aged monkey transitioned to menopause, experiencing cycle irregularity over 4 y, eventual cessation of menses, and plasma AMH below the level of detection. Finally, with increasing age, the percentage of female vervets with offspring declined significantly. The present study provides insight into ovarian aging and reproductive senescence in vervet monkeys. Results highlight the importance of considering this nonhuman primate as a model to investigate the relationships between ovarian aging and chronic disease risk.

A 2.25-y-old male pigtailed macaque (Macaca nemestrina) was experimentally irradiated and received a bone marrow transplant. After transplantation and engraftment, the macaque had unexpected recurring pancytopenia and dependent edema of the prepuce, scrotum, and legs. The diagnostic work-up included a blood smear, which revealed a trypomastigote consistent with Trypanosoma cruzi, the causative agent of Chagas disease (CD). We initially hypothesized that the macaque had acquired the infection when it lived in Georgia. However, because the animal had received multiple blood transfusions, all blood donors were screened for CD. One male pigtailed macaque blood donor, which was previously housed in Louisiana, was positive for T. cruzi antibodies via serology. Due to the low prevalence of infection in Georgia, the blood transfusion was hypothesized to be the source of T. cruzi infection. The transfusion was confirmed as the mechanism of transmission when screening of archived serum revealed seroconversion after blood transfusion from the seropositive blood donor. The macaque made a full clinical recovery, and further follow-up including thoracic radiography, echocardiography, and gross necropsy did not show any abnormalities associated with CD. Other animals that received blood transfusions from the positive blood donor were tested, and one additional pigtailed macaque on the same research protocol was positive for T. cruzi. Although CD has been reported to occur in many nonhuman primate species, especially pigtailed macaques, the transmission of CD via blood transfusion in nonhuman primates has not been reported previously.

An incidental, asymptomatic, well-circumscribed, solitary, submucosal nodular mass was detected on the mucosal surface of the inner lower lip in a female cynomolgus macaque (age, approximately 2.4 y) during a juvenile chronic toxicology study. Grossly, the nodule was soft with brown to tan discoloration and measured approximately 4 mm in diameter. Microscopically, the nodule was covered by normal stratified squamous epithelium and composed of well-circumscribed irregular lobules containing hyperplastic and normal-appearing mucinous salivary gland acini and ducts, which were separated by thick connective tissue septae. In light of the gross pathology and results of microscopic examination, salivary gland hamartoma was diagnosed. This lesion resembles adenomatoid hyperplasia of mucous salivary glands in humans, which is a rare nonneoplastic swelling. To our knowledge, this case description is the first report of a cynomolgus macaque with the rare entity of lip salivary gland hamartoma, which likely represents adenomatous hyperplasia in humans.

A 10-y-old ovariohysterectomized ring-tailed lemur (Lemur catta) was presented for exacerbation of respiratory signs. The lemur had a history of multiple examinations for various problems, including traumatic lacerations and recurrent perivulvar dermatitis. Examination revealed abnormal lung sounds and a femoral arteriovenous fistula with a palpable thrill and auscultable bruit in the right inguinal area. A diagnosis of congestive heart failure was made on the basis of exam findings, radiography, abdominal ultrasonography, and echocardiography. The lemur was maintained on furosemide until surgical ligation of the fistula was performed. Postoperative examination confirmed successful closure of the fistula and resolution of the signs of heart failure. Arteriovenous fistulas are abnormal connections between an artery and a vein that bypass the capillary bed. Large arteriovenous fistulas may result in decreased peripheral resistance and an increase in cardiac output with consequent cardiomegaly and high output heart failure. This lemur's high-flow arteriovenous fistula with secondary heart failure may have been iatrogenically induced during blood collection by prior femoral venipuncture. To our knowledge, this report is the first description of an arteriovenous fistula in a prosimian. Successful surgical correction of suspected iatrogenic femoral arteriovenous fistulas in a cynomolgus monkey (Macaca fascicularis) and a rhesus macaque (Macaca mulatta) have been reported previously. Arteriovenous fistula formation should be considered as a rare potential complication of venipuncture and as a treatable cause of congestive heart failure in lemurs.