The physical, clinicopathologic, and survival rates of 77 cats with severe spontaneous hepatic lipidosis are detailed in this report. Cats were subdivided into groups designated as idiopathic lipidosis if no other disease process was recognized, or secondary lipidosis if another disease process was diagnosed. Cats were also subdivided into groups designated a s survivors or nonsurvivors on the basis of successful recuperation at 4 months after initial diagnosis. Differences between disease and survival groups were evaluated for significance. Overall, more female cats and middle-aged cats were affected. Presenting complaints of vomiting, anorexia, weakness, and weight loss were common. Physical assessment of most cats showed obvious hepatomegaly, jaundice, dehydration, and a weight loss 2 25% of usual body weight. Neurobehavioral signs indicative of hepatic encephalopathy, other than ptyalism and depression, were rare. Clinicopathologic features are characterized by hyperbilirubinemia and increased activities of serum ALT, AST, and ALP, with only small if any increase in yGT activity, Clinical features distinguishing cats with hepatic lipidosis from those with other serious cholestatic disorders include absence of hyperglobulinemia and low y C T activity relative to ALP activity. Although coagulation tests were abnormal in 45% of cats tested (n = 44), few cats showed clinical bleeding tendencies. Most cats received prophylactic vitamin K, therapy. Forty two cats received aggressive nutritional and supportive care and of these 55% survived. Cats with idiopathic disease were significantly younger, had significantly higher ALP activity and bilirubin concentration, and had a slightly better survival rate than cats with secondary lipidosis. Low PCV, hypokalemia, and an older age were significantly related to nonsurvival. Because of the variety of diets and food supplements used in case management, the influence of nutritional factors on survival could not be evaluated. THE FELINE HEPATOCYTE appears to have a pro-. . pensity for lipid vacuole formation in a variety of systemic disease processes.' Mild to moderate hepatic lipi-

This communication describes the application of an existing intracellular methodology to the quantitation of tenofovir-diphosphate (TFV-DP) and emtricitabine-triphosphate (FTC-TP) from erythrocytes using dried blood spots (DBS). Concentrations were determined from a 3mm DBS punch extracted into a 70:30 methanol:water solution (lysed cellular matrix). This extraction solution was then subjected to a previously validated analytical procedure for lysed cellular matrix. Experiments for DBS validation used replicate samples from study participants to demonstrate acceptable reproducibility with spot volumes ranging from 10μL to 50μL and punch location either from the edge or center of the spot. Analysis of paired DBS with purified red blood cells showed that a 3mm DBS punch contained an average of 11.9 million cells for the observed hematocrit range of the participants (35% to 50%). Numerous stability tests were completed showing that whole blood in an EDTA vacutainer could sit for 24 hours at room temperature prior to spotting, and DBS could remain at room temperature for up to five days including shipment at ambient using 2-day delivery. DBS stability in storage was acceptable up to 18 months at −20°C or −80°C and DBS could undergo 4 Freeze/Thaw cycles. The described method was applied to HIV prophylaxis studies, demonstrating powerful associations with HIV acquisition through its ability to discriminate gradients of adherence.

The pharmacokinetics (PK) of tenofovir-diphosphate (TFV-DP) and emtricitabine-triphosphate (FTC-TP), the active anabolites of tenofovir disoproxil fumarate (TDF), and emtricitabine (FTC) in blood, genital, and rectal compartments was determined in HIV-positive and seronegative adults who undertook a 60-day intensive PK study of daily TDF/FTC (plus efavirenz in HIV positives). Lymphocyte cell sorting, genital, and rectal sampling occurred once per subject, at staggered visits. Among 19 HIV-positive (3 female) and 21 seronegative (10 female) adults, TFV-DP in peripheral blood mononuclear cells (PBMC) accumulated 8.6-fold [95% confidence interval (CI): 7.2-10] from first-dose to steady-state concentration (Css) versus 1.7-fold (95% CI: 1.5-1.9) for FTC-TP. Css was reached in ∼11 and 3 days, respectively. Css values were similar between HIV-negative and HIV-positive individuals. Css TFV-DP in rectal mononuclear cells (1,450 fmol/10 cells, 898-2,340) was achieved in 5 days and was >10 times higher than PBMC (95 fmol/10 cells, 85-106), seminal cells (22 fmol/10 cells, 6-79), and cervical cells (111 fmol/10 cells, 64-194). FTC-TP Css was highest in PBMC (5.7 pmol/10 cells, 5.2-6.1) and cervical cells (7 pmol/10 cells, 2-19) versus rectal (0.8 pmol/10 cells, 0.6-1.1) and seminal cells (0.3 pmol/10 cells, 0.2-0.5). Genital drug concentrations on days 1-7 overlapped with estimated Css, but accumulation characteristics were based on limited data. TFV-DP and FTC-TP in cell sorted samples were highest and achieved most rapidly in CD14 compared with CD4, CD8, and CD19 cells. Together, these findings demonstrate cell-type and tissue-dependent cellular pharmacology, preferential accumulation of TFV-DP in rectal mononuclear cells, and rapid distribution into rectal and genital compartments.