Resolution-dependent estimates of multiple sclerosis lesion loads.

BACKGROUND: Changes in brain lesion loads assessed with magnetic resonance imaging obtained at 1.5 Telsa (T) are used as a measure of disease evolution in natural history studies and treatment trials of multiple sclerosis. METHODS: A comparison was made between the total lesion volume and individual lesions observed on 1.5 T images and on high-resolution 4 T images. Lesions were quantified using a computer-assisted segmentation tool. RESULTS: There was a 46% increase in the total number of lesions detected with 4 T versus 1.5 T imaging (p < 0.005). The 4 T also showed a 60% increase in total lesion volume when compared with the 1.5 T (p < 0.005). In several instances, the 1.5 T scans showed individual lesions that coalesced into larger areas of abnormality in the 4 T scans. The relationship between individual lesion volumes was linear (slope 1.231) showing that the lesion volume observed at 4 T increased with the size of the lesion detected at 1.5 T. The 4 T voxels were less than one quarter the size of those used at 1.5 T and there were no consistent differences between their signal-to-noise ratios. CONCLUSIONS: The increase in signal strength that accompanied the increase in field strength compensated for the loss in signal amplitude produced by the use of smaller voxels. This enabled the acquisition of images with improved resolution, resulting in increased lesion detection at 4 T and larger lesion volumes.

Plasma chemistry in peregrine falcons (Falco peregrinus): Reference values and physiological variations of importance for interpretation.

Reference values (inner limits of the percentiles P(2.5) and P(97.5) are given with a probability of 95%) for 21 plasma chemical variables were established in 79 peregrine falcons (Falco peregrinus). The following values were established: urea 0.8 to 3.9 mmol/l, creatinine 24 to 64 mumol/l, glucose 16.5 to 22.0 mmol/l, sodium 150 to 170 mmol/l, chloride 114 to 131 mmol/I, inorganic phosphorus 0.55 to 1.53 mmol/l, osmolal-ity 322 to 356 mOsmol/kg, alkaline phosphatase 31 to 121 IU/l, alanine aminotransferase 29 to 90 IU/l, aspartate aminotransferase 34 to 116 U/l, gamma glutamyl transferase 0 to 3 IU/l, lactate dehydrogenase 1008 to 2650 IU/l, creatine kinase 120 to 442 IU/l, cholinesterase 143 to 325 IU/1, glutamate dehydrogenase < 8 IU/l, total bile acids 5 to 69 mumol/l, uric acid 253 to 995 mumol/l, total protein 24 to 39 g/l, albumin 12.7 to 22.4 g/l. Reference values for the calculated albumin/globulin (A/G) ratio were 0.8 to 24. Based on previous studies, reference values for calcium were established using an adjustment formula using plasma total protein concentrations (before correction 1.86 to 2.49, after correction 1.97 to 2.46 mmol/l). Results of plasma potassium concentrations were erratic which was shown to be due to a time lag between sample collection and separation of plasma and cells.

Relationship of plasma total protein and albumin to total calcium in peregrine falcons (Falco peregrinus).

A significant correlation was found between total calcium and total protein concentration in 124 plasma samples of captive peregrine falcons (r = 0.65; P<0.01). About 42% of the variability in calcium was attributable to the change in the plasma total protein concentration (R2 = 0.417). The correlation between calcium and albumin was significant (r = 0.33; P<0.01), but significantly smaller than the correlation between calcium and total protein (P<0.01). Only 11% of the plasma calcium concentration was attributable to difference in concentration of albumin (R2 = 0.108). An adjustment formula for plasma calcium concentration in the peregrine falcon was derived on the basis of the total protein concentration: Adj.Ca (mmol/1) = Ca (mmol/1) -0.02 Total protein (g/1) + 0.67.

Chimpanzee holding, rehabilitation and breeding: facilities design and colony management.

A multipurpose chimpanzee facility was designed and constructed to provide the unique housing requirements of rehabilitating laboratory-raised, behaviorally-deficient chimpanzees. The housing complex provided quarantine facilities, single or group housing for long-term holding, and semi-free-ranging compounds for established breeding groups. The facilities were designed to accommodate 170 animals of diverse ages and group configurations. Reproductive performance of the chimpanzees resulted in the production of 0.41 live infants per adult female year. Information was also given on the care, diet, maintenance, health status, handling, and rehabilitation of the chimpanzee. Development of this facility has made it practical to house large numbers of chimpanzees economically and conveniently in an enriched environment which promotes breeding and contributes to the survival of this irreplaceable animal model.

Direct inguinal hernia in the cynomolgus monkey (Macaca fascicularis).

The surgical repair of a direct inguinal hernia in Macaca fascicularis using the posterior or preperitoneal approach is presented. The success of this surgical approach endorses it as an excellent method of repairing direct inguinal hernia in male primates.

Reproductive, gestational, and newborn physiology of the chimpanzee.

The Yerkes Regional Primate Research Center has successfully bred chimpanzees since 1930. Breeding statistics for the last 6 yr and problems of fetal waste and infant mortality are presented here. Experience with a potential advantages of semi-free-ranging breeding systems are presented. This 6-yr study period also produced considerable information on gestational and newborn physiology.