Severe DRESS with myocarditis secondary to naproxen/esomeprazole

A man in his 60s presented with a widespread erythematous rash and associated chills, paraesthesia and haematuria. He had recently commenced naproxen/esomeprazole. Blood tests showed hypereosinophilia (0.73×109/L) and moderate acute kidney injury. Histology revealed parakeratosis, mild spongiosis with eosinophils. He developed acute coronary syndrome with rapid atrial fibrillation. Coronary angiogram was non-obstructive. Cardiac MRI (CMR) revealed acute myocarditis secondary to Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). Naproxen/esomeprazole was discontinued, and he was supported with oral corticosteroids. A repeat CMR 3 months later showed resolution of myocarditis. Naproxen/esomeprazole is not a common offending drug. DRESS is a rare drug-induced hypersensitivity reaction with a mortality rate of 10%. The objective of this case report is to highlight the significant but rare cardiac complications that can ensue from DRESS, which warrant prompt recognition and withdrawal of the causative drug.

Surgical resolution of uterine prolapse in three pet rabbits

This report describes a surgical technique for resolution of uterine prolapse in rabbits. Three pet rabbits presented within 24 hours of parturition with a red mass protruding from the vagina, which was diagnosed as uterine prolapse. In the first case, an attempt to reduce the prolapse by manual compression was ineffective. A laparotomy was used to apply internal uterine traction while simultaneously using gentle external pressure with cotton-tip applicators and resulted in successful resolution. After repositioning, an ovariohysterovaginectomy was performed in all three rabbits. All rabbits recovered uneventfully. Laparotomic repositioning of the uterus and ovariohysterovaginectomy, not previously described in rabbits, was easy to perform and permitted resolution of uterine prolapse.

Unexpected inhibition of cholesterol 7 alpha-hydroxylase by cholesterol in New Zealand white and Watanabe heritable hyperlipidemic rabbits

We investigated the effect of cholesterol feeding on plasma cholesterol concentrations, hepatic activities and mRNA levels of HMG-CoA reductase and cholesterol 7 alpha-hydroxylase and hepatic LDL receptor function and mRNA levels in 23 New Zealand White (NZW) and 17 Watanabe heritable hyperlipidemic (WHHL) rabbits. Plasma cholesterol concentrations were 9.9 times greater in WHHL than NZW rabbits and rose significantly in both groups when cholesterol was fed. Baseline liver cholesterol levels were 50% higher but rose only 26% in WHHL as compared with 3.6-fold increase with the cholesterol diet in NZW rabbits. In both rabbit groups, hepatic total HMG-CoA reductase activity was similar and declined > 60% without changing enzyme mRNA levels after cholesterol was fed. In NZW rabbits, cholesterol feeding inhibited LDL receptor function but not mRNA levels. As expected, receptor-mediated LDL binding was reduced in WHHL rabbits. Hepatic cholesterol 7 alpha-hydroxylase activity and mRNA levels were 2.8 and 10.4 times greater in NZW than WHHL rabbits. Unexpectedly, cholesterol 7 alpha-hydroxylase activity was reduced 53% and mRNA levels were reduced 79% in NZW rabbits with 2% cholesterol feeding. These results demonstrate that WHHL as compared with NZW rabbits have markedly elevated plasma and higher liver cholesterol concentrations, less hepatic LDL receptor function, and very low hepatic cholesterol 7 alpha-hydroxylase activity and mRNA levels. Feeding cholesterol to NZW rabbits increased plasma and hepatic concentrations greatly, inhibited LDL receptor-mediated binding, and unexpectedly suppressed cholesterol 7 alpha-hydroxylase activity and mRNA to minimum levels similar to WHHL rabbits. Dietary cholesterol accumulates in the plasma of NZW rabbits, and WHHL rabbits are hypercholesterolemic because reduced LDL receptor function is combined with decreased catabolism of cholesterol to bile acids.

In vivo protection against endotoxin by plasma high density lipoprotein

Overwhelming bacterial infection is accompanied by fever, hypotension, disseminated intravascular coagulation, and multiple organ failure leading to death in 30-80% of cases. These classical symptoms of septic shock are caused by potent cytokines that are produced in response to endotoxin released from Gram-negative bacteria. Treatments with antibodies and receptor antagonists to block endotoxin or cytokine mediators have given mixed results in clinical trials. High density lipoprotein (HDL) is a natural component of plasma that is known to neutralize endotoxin in vitro. We report here that raising the plasma HDL concentration protects mice against endotoxin in vivo. Transgenic mice with 2-fold-elevated plasma HDL levels had more endotoxin bound to HDL, lower plasma cytokine levels, and improved survival rates compared with low-HDL mice. Intravenous infusion of HDL also protected mice, but only when given as reconstituted HDL prepared from phospholipid and either HDL apoprotein or an 18-amino acid peptide synthesized to mimic the structure of apolipoprotein A-I of HDL. Intact plasma HDL was mildly toxic, and HDL apoprotein was ineffective. The effectiveness of the reconstituted peptide renders very unlikely any significant contribution to protection by trace proteins in apo-HDL. These data suggest a simple leaflet insertion model for binding and neutralization of lipopolysaccharide by phospholipid on the surface of HDL. Plasma HDL may normally act to protect against endotoxin; this protection may be augmented by administration of reconstituted HDL or reconstituted peptides.

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.

Control of variance in experimental studies of hyperlipidemia using the WHHL rabbit

Between-animal variability has frustrated many experimental studies in outbred animal models of human disease. Variability that arises from genetic heterozygosity can be minimized by use of experimental designs that match littermates (polyzygotic twins) across control and treatment groups. Poor breeding vigor has prevented use of this experimental design in the WHHL rabbit model of hyperlipidemia and atherosclerosis. A comparison of reproduction in WHHL and normal rabbits demonstrated that litter size is limited by functional deficits at ovulation, implantation, and gestation in WHHL females. Superovulation of females reliably produced expanded litters of WHHL rabbits. Plasma lipids were measured in expanded litters of Japanese White WHHL (JW-WW) and English Half-lop WHHL (EHL-WW) rabbits. The variance of plasma cholesterol within sibships was two- to three-fold less than that between-litters. Intraclass correlation of total cholesterol within litters of EHL-WW was 0.72 and within litters of JW-WW was 0.67. These data provide evidence of genetic modulation of hypercholesterolemia in WHHL rabbits and demonstrate that experimental designs in which littermates are paired across groups can decrease the number of animals needed or increase the sensitivity of hypothesis tests by two- to threefold.

The physical-chemical basis for sex-related differences in uptake of fatty acids by the liver

The uptake of fatty acids by the liver was shown previously to be a non-catalyzed process, and rates of uptake were correlated to the affinity of the plasma membranes of liver cells for fatty acids. The experiments in this paper were designed to test whether the known differences in uptake and metabolism of free fatty acids by the livers of male and female rats could be understood based on differences in the affinities of the corresponding plasma membranes for these substrates. The relative affinities for palmitate and oleate of 'male' plasma membranes were found to be lower versus 'female' membranes. Measurements of uptake of palmitate from albumin-palmitate complexes by 'male' and 'female' perfused livers showed higher uptake rates by the latter when correlated with the concentration of the complex. However, the rates of uptake were identical when the concentrations of the fatty acid in the plasma membranes of male and female liver cells were the same.

Low density lipoprotein receptor-independent hepatic uptake of a synthetic, cholesterol-scavenging lipoprotein: implications for the treatment of receptor-deficient atherosclerosis

The metabolism of infused 111In-labeled phospholipid liposomes was examined in Watanabe heritable hyperlipidemic (WHHL) rabbits, which lack low density lipoprotein (LDL) receptors, and in normal control rabbits. The half-times (t1/2) for clearance of 111In and excess phospholipid from plasma were 20.8 +/- 0.9 hr and 20.3 +/- 4.6 hr in WHHL and 20.0 +/- 0.8 hr and 19.6 +/- 2.2 hr in the normal rabbits (means +/- SEM; n = 4). By 6 hr postinfusion, the plasma concentration of unesterified cholesterol increased by 2.2 +/- 0.23 mmol/liter in WHHL and 2.1 +/- 0.04 mmol/liter in normal rabbits, presumably reflecting mobilization of tissue stores. Disappearance of excess plasma cholesterol was greater than 90% complete in both groups of rabbits by 70 hr postinfusion. By quantitative gamma camera imaging, hepatic trapping of 111In-labeled liposomes over time was indistinguishable between the two groups. At autopsy, the liver was the major organ of clearance, acquiring 22.0% +/- 1.7% (WHHL) and 16.8% +/- 1.0% (normal of total 111In. Aortic uptake of 111In was less than 0.02%. Thus, mobilization of cholesterol and hepatic uptake of phospholipid liposomes do not require LDL receptors. Because phospholipid infusions produce rapid substantial regression of atherosclerosis in genetically normal animals, our results suggest that phospholipid liposomes or triglyceride phospholipid emulsions (e.g., Intralipid) might reduce atherosclerosis in WHHL rabbits and in humans with familial hypercholesterolemia.

Physical-chemical model for the entry of water-insoluble compounds into cells. Studies of fatty acid uptake by the liver

The spontaneous transfer of water-insoluble substances from plasma to the interior of cells would involve a series of steps in which the substance of interest dissociates from albumin in plasma, enters the outer half of the plasma membrane of a cell, crosses the bilayer, and then dissociates from the inner half of the plasma membrane to enter cell cytosol and diffuses to sites of its metabolism. We have examined the behavior of long-chain fatty acids in the uptake process, assuming that none of these steps is facilitated by the cell during the entry of fatty acids into the liver. Comparison of the spontaneous rates for each individual step with rates of uptake of fatty acid by perfused liver leads to the conclusion that the uptake of fatty acids is not limited by kinetic factors but is determined instead by the equilibrium distribution (Keq) of fatty acids between albumin in plasma and the phospholipids of the plasma membrane. This idea was examined further by determining whether there was a relationship between the value for Keq and rates of uptake of a fatty acid and the pattern of kinetics for uptake. The data indicate that there is a linear relationship between Keq and the rate of uptake, that uptake rates can be predicted with a high degree of accuracy from thermodynamic data, and that the pattern of kinetics of uptake is compatible with the idea that the uptake rate is determined by the relative affinity of a fatty acid for albumin and membranes.

Susceptibility of laboratory rats, hamsters, and mice to wound infection with Staphylococcus aureus

Response of rodents to experimentally induced subcutaneous infection was examined to determine whether laboratory rats used in invasive procedures have a superior ability to withstand wound infection than do hamsters and mice. Rats, hamsters, and mice were injected subcutaneously with 10(9), 10(7), and 10(5) colony-forming units of Staphylococcus aureus. Quantitative counts of viable S aureus from the injection site, bacteriologic cultures of heart blood, and histologic examinations of the subcutaneous tissues were performed. Multiple linear regression of the quantitative data and equality of regression lines among groups were determined. Results indicated that the ability to eliminate bacteria varied between species and depended on the dose injected within each species. Compared with hamsters and mice at all doses, rats eliminated bacteria faster and had the mildest and most rapidly organized inflammatory response after inoculation. Experimental bacteremia developed in 3.7% of all animals evaluated, with no species-specific pattern. The rat was more resistant to localized wound infection with S aureus than were hamsters and mice.

Vulnerability to stress-induced tumor growth increases with age in rats: role of glucocorticoids

Aged males rats show a delay in terminating their adrenocortical stress response and, thus, hypersecrete corticosterone during the poststress period. Because of the numerous catabolic effects of corticosterone, we hypothesized that chronic stress should induce greater pathophysiological changes in aged than in young subjects. We report that stress-induced tumor growth, associated with inoculation with fetal rats cells transformed by tumor virus, is accelerated in aged rats. Furthermore, simulation of the aged pattern of corticosterone hypersecretion in young animals using steroid administration similarly accelerates stress-induced tumor growth.

An epornitic of avian pox in a research aviary

An outbreak of avian pox in a bird research colony was reported. Although 10 species of passerine birds were housed within the facility, clinical signs and mortality were restricted to canaries and house sparrows. Post-mortem lesions initially occurred in the upper and lower respiratory tracts and were characterized by proliferative rhinitis, proliferative bronchopneumonia, and proliferative airsacculitis, and diphtheritic lesions occurring in the esophagus were characterized by proliferative granulomatous esophagitis. Cutaneous lesions occurred subsequently in some birds, and a diagnosis was made by histopathology, electron microscopy, and virus isolation. The occurrence of diphtheritic lesions in pox infections of wild birds has been rare, and a sparrow showed an unusual combination of both diphtheritic and acute systemic lesions previously undescribed.

A suspected new canine storage disease

This paper describes three cases of what is probably a new form of storage disorder. The affected animals were English Springer Spaniels and they had developed progressive neurological signs when 2-3 years old. They had gross enlargement of the vagi and of the spinal nerves supplying the brachial plexus. By light microscopy in these nerves these were massive amounts of endoneurial loose fibrous tissue with dispersion of nerve fibres and many foamy phagocyte-like cells. In the central nervous system there was very severe cytoplasmic vacuolation of most neurones and neuroglia, perivascular phagocyte-like cells, loss of myelin, loss of Purkinje cells, numerous spheroids, hypertrophic astrocytes and fibrous astrocytosis. There was also foamy cytoplasmic vacuolation of renal convoluted tubules and pancreatic exocrine parenchyma and numerous foamy phagocyte-like cells in lymph node and lung. On ultrastructural examination membrane bound vacuoles were present in the cytoplasm of affected neurones and phagocyte-like cells. Most of the vacuoles were empty, some contained amorphous materials and some, in neurones, contained stacks of curved or straight lamellae. It is suggested that the stored material could be an oligosaccharide.