Thomas M. Donnelly

High-frequency analysis of the signal-averaged ECG. Correlation with left ventricular mass in rabbits.

Standard electrocardiographic (ECG) criteria have exhibited poor correlation with left ventricular mass and poor sensitivity for left ventricular hypertrophy at acceptable levels of specificity. To assess the ability of the high-frequency filtered signal-averaged ECG to improve ECG correlation with left ventricular mass, signal-averaged orthogonal lead recordings in 29 normal rabbits and seven rabbits with left ventricular hypertrophy due to chronic aortic regurgitation were compared with left ventricular mass corrected for body weight. Voltage of the vector QRS complex was integrated over the total duration of the QRS after separate filtering with standard frequency (0-100 Hz) low-pass and high-frequency (44 Hz) high-pass filters. Measurement of individual X, Y, and Z lead R and S wave voltage was performed on averaged, standard frequency filtered complexes, and the maximal spatial vector magnitude was determined from the standard frequency filtered vectors. Voltage of the 44 Hz high-pass filtered vector QRS complex integrated over the total duration of the QRS (high-frequency vector integral) correlated closely with indexed left ventricular mass (r = 0.84, p less than 0.0001), significantly better than the correlation of standard frequency vector integral or maximal spatial vector magnitude voltages (r = 0.35 and r = 0.61, each p less than 0.01 vs high-frequency vector integral) and the correlation of orthogonal lead X R wave or lead Y S wave voltages (r = 0.55 and r = 0.37, respectively, each p less than 0.01 vs high-frequency vector integral).(ABSTRACT TRUNCATED AT 250 WORDS)

Husbandry, reproduction and postnatal development of the Neotropical muroid rodent Zygodontomys brevicauda

Laboratory colonies of the Neotropical muroid rodent Zygodontomys brevicauda have been employed in studies of arbovirus epidemiology and are currently the subjects of experimental research on tropical mammalian reproductive physiology and evolutionary quantitative genetics. Captive-bred litters typically consist of 4 or 5 pups weighing 3-4 g each at birth. Adults 20-40 weeks old average 60-80 g with some sexual dimorphism. Females are sexually mature at 3-4 weeks of age, males at 6-8 weeks. Ovulation is spontaneous and gestation is 25 days. Preliminary observations are provided on the microbiological status and parasites of captive-bred animals.

Reply to 'A closer look: secondary glaucoma more likely'

Column Editor replies: In some tissues, anatomical details are relatively simple and easily analyzed histologically. The eye, however, is a complex structure with important regional anatomical variations that make histological interpretation challenging at best. If the orientation of the eye during sectioning is not carefully controlled, it is easy to make erroneous interpretations. For this and other reasons, eye pathology is a recognized subspecialty of pathology.

What's your diagnosis? Thread-like Worms in the Abdominal Cavity of a Squirrel Monkey

a female squirrel monkey (Saimiri sciureus), we found large numbers of long, slender worms in the animal’s abdominal cavity. The monkey belonged to a colony of squirrel monkeys used for malaria research. It had been group-housed in a large home cage with enrichment toys, as a member of a cohesive social group consisting predominantly of adult females with their young and some juveniles and adult males. The room temperature was kept at 74 ± 3°F and the humidity was 60–70% ± 10%, in an attempt to mimic warm, humid jungle conditions. Air changes were set at 12–15/h and the room was on a 12 h lightdark cycle. Animal technicians fed the monkeys a commercial New World nonhuman primate (NHP) diet fortified with vitamin D3, along with fresh fruits and vegetables. An automatic watering system provided water ad libitum. This female monkey had been in the colony for eight years and its individual history record indicated the facility had received it as a wild-caught monkey. During the eight years in the colony, it had given birth several times. The record did not show where in South America the NHP importers had captured the monkey. Instead, it identified the animal only as Saimiri sciureus. All squirrel monkeys were once considered a single species (S. sciureus) with several geographically separated subspecies; however, karyotypic and weighed the animal and compared its present weight (0.72 kg) with a previous weighing six months earlier (0.85 kg). We notified the investigator of our findings and asked if he wanted further diagnostic work-up. Due to the animal’s age, the investigator decided to euthanize the monkey and use its fresh organs for cell culture studies and her serum for immunological studies. We euthanized the monkey with an intravenous dose of phenobarbital after heavy sedation with ketamine. When we opened the abdomen, we noticed the long slender worms on the surface of the liver and within the cavity (Fig. 1). There were no abnormal gross findings at necropsy. Can you identify the worms based on their gross appearance? What types of worms are most likely to be found in the abdominal cavity of New World monkeys? Where do the worms come from? Are the worms associated with the animal’s weight loss? Do the worms pose a hazard to other monkeys or humans?

Sudden death in an anorectic cynomolgus macaque. Fatal fasting syndrome of obese macaques.

property upon which its primary animal facility was found, it moved its crab-eating macaques (Macaca fascicularis) to a facility run by a contract research organization (CRO). The biotechnology company had successfully pair-housed nearly all the macaques six years previously as part of its enrichment program. Besides the pair housing, the biotechnology company developed an environmental enrichment program that consisted of sturdy cage toys, shelves and perching branches, novel food treats, and a color television in each animal room that showed cartoon videos. The enrichment program appeared beneficial not only for the monkeys but also for the animal technicians who came to know the behavior, likes and dislikes of each monkey. The biotechnology company’s animal facility staff provided the CRO with detailed records not only on the medical history of each animal, but the idiosyncrasies they found with each animal such as its favorite food treats, difficulty or ease in handling, and potential for self mutilation. The CRO animal facility technicians observed a ten-year-old female monkey pulling hair from its arms soon after its arrival. This monkey did not have a history of behavioral problems, illness, or injury, and it remained pair-housed with the same cage mate in the new facility. Despite the technicians offering the monkey its favorite treats, it shortly progressed to sitting on the floor of its new cage. The facility manager then moved the monkey to a single cage in a room where other monkeys with behavioral abnormalities where placed. Although all the monkeys in this room were single saw moderate to severe vacuolation of the proximal renal tubular epithelium. A few tubules were necrotic and contained granular or crystalline material. Vacuoles present in frozen sections of formalin fixed liver and kidney stained with Oil Red O were positive for neutral fats (Fig. 1). Mild to moderate, multifocal areas of pancreatic necrosis were present in some lobules. However, the most striking aspects of the pancreas were the pale exocrine pancreatic cells with little or no zymogen granules lining moderate to severe dilated acini. Some dilated acini contained floccular eosinophilic inspissated secretions that were PAS-positive. What is the cause of death in this monkey? Is this a recognized syndrome? What are the white granules in the abdominal fat? What has happened to the pancreas?