A rapid method for detection of cellular proliferation using carboxyfluorescein. Assay of growth factors (IL-2, IL-1) and growth inhibiting antibodies

The uptake of carboxyfluorescein diacetate (CFDA) into live cells was used as the basis for a simple, rapid and fully automated micromethod for determination of cell growth. The aim of the investigation was to adapt the CFDA method for detection of cell growth factors from cell culture supernatants. Thus, the biological activities of the growth factors IL-2 or IL-1 could be detected and quantitated at the same level of sensitivity as with the conventional [3H]thymidine incorporation. Similarly, the method was well suited to assay inhibition of IL-2-dependent lymphocyte growth by the monoclonal antibody anti-Tac, binding to the human lymphocyte membrane receptor for IL-2. The CFDA method proved to be rapid, reliable and well suited for several applications involving limiting numbers of cells and biological reagents.

Amebiasis in red-footed tortoises

Of 500 red-footed tortoises imported to southern Florida, approximately 200 died during a 2-month period. Clinical signs were nonspecific and included anorexia, listlessness, and watery diarrhea, with lingering death. Necropsy consistently revealed thickened duodenum, with necrotic mucosa and multifocal to diffuse areas of hepatic necrosis. Histologic evaluation of tissues demonstrated numerous amebae in intestinal and hepatic lesions.

Taurine uptake by cultured human lymphoblastoid cells

Cultured human lymphoblastoid cells take up taurine from the medium by two processes: 1) a temperature-dependent, Na+-dependent, saturable "active"-transport system and 2) diffusion. The active transport has properties similar to those reported for taurine transport by other tissues. Apparent Km is about 25 microM and Vmax about 7.2 pmol/min/10(6) cells; saturation occurs at 100 microM taurine. Uptake is competitively inhibited by the beta-amino acids hypotaurine (50% inhibition at 44 microM) and beta-alanine (50% at 152 microM), as measured at 50 microM taurine. Taurocyamine inhibits 50% at 260 microM. Chlorpromazine and imipramine are strong uncompetitive inhibitors, giving 50% inhibition at 26 microM and 115 microM, respectively; at these concentrations cellular viability per se is not affected. Ouabain inhibits 40-50% over a concentration range of 4-500 microM. Diffusion of taurine into the cells is proportional to concentration up to 20 mM. However, at the concentration of taurine in human plasma, 40-100 microM, active transport would provide 90% of the taurine taken up.

Safety and efficacy of intravenous quinidine

The safety and efficacy of intravenous quinidine were evaluated in a patient population with a high prevalence of left ventricular dysfunction and intraventricular conduction delays. Quinidine gluconate (mean dose 9.1 +/- 1.6 mg/kg) was administered during electrophysiologic study to 100 patients with ventricular or supraventricular tachyarrhythmias. Clinical heart failure was present in 68 percent of the patients. Left ventricular end-diastolic pressure, cardiac index, and left ventricular ejection fraction were abnormal in 62, 48, and 70 percent, respectively. Major intraventricular conduction delays (QRS of 120 msec or more) were present in 27 percent, and the H-V interval was prolonged (over 55 msec) in 28 percent. Despite the prevalence of these abnormalities, quinidine was discontinued because of hypotension in only 10 patients. Saline solution was infused to maintain preload in 37 percent, and hypotension responded promptly to saline solution infusion or discontinuation of quinidine infusion in all subjects. Hypotension was not more common in patients with more severe left ventricular dysfunction. QRS duration, H-V interval, QTc, and right ventricular effective refractory period increased significantly (p less than 0.001) after quinidine administration. Heart block or QRS widening of 50 percent or more did not occur. Quinidine prevented arrhythmia induction in 26 percent of patients who received full doses. Ventricular tachycardia cycle length increased in all 41 patients in whom identical forms were induced before and after quinidine (287 +/- 71 msec versus 361 +/- 93 msec, p less than 0.001). Intravenous quinidine may be administered safely to patients with intraventricular conduction delays and moderate heart failure. When antiarrhythmic efficacy is assessed by electrophysiologic study, quinidine compares favorably with other antiarrhythmic agents.

Lymphosarcoma in an Eastern king snake and a rhinoceros viper

An antemortem diagnosis of lymphosarcoma was made in a captive Eastern king snake and a rhinoceros viper. The Eastern king snake died on the 1st day after biopsy of a liver nodule, and necropsy revealed multiple tumor nodules throughout all major organ systems. The rhinoceros viper died after chemotherapy with cytosine arabinoside. The major gross lesion was a large paracolonic coelomic tumor that extended into the adjacent musculature and subcutaneous tissue of the lateral abdominal wall. The immediate cause of death of the rhinoceros viper was believed to be severe renal tubular necrosis.

Illness associated with paramyxo-like virus infection in a zoologic collection of snakes

Of 438 snakes in a zoologic collection, 35 died during a 3-month period; all were members of the family Viperidae. Clinical signs consisted of gaping of the mouth followed within 1 day by convulsions. All necropsied animals had a mucoid exudate throughout the respiratory tract. Histologic evaluation of lung revealed evidence of interstitial pneumonia, with occasional eosinophilic intracytoplasmic inclusions in epithelial cells. A paramyxo-like virus, isolated in viper heart cells from lung tissue, was observed by electron microscopy to be budding from cell membranes. The virus hemagglutinated chicken red blood cells at 5 C, and antibody titers were assayed by hemagglutination inhibition. In a random survey of 22 snakes from the zoologic collection, antibody titers to the virus ranged from 1/20 to 1/2,560.

Regulation of dimorphism in Histoplasma capsulatum by cyclic adenosine 3',5'-monophosphate

During temperature-induced transition of the dimorphic pathogenic fungus Histoplasma capsulatum from the single yeast cell form to the multicellular mycelial form, there was an increase in intracellular cyclic adenosine 3',5'-monophosphate (cAMP) levels as well as a striking accumulation of cAMP in the medium. cAMP levels also changed during the reverse mycelium-to-yeast transition.

Glycoprotein synthesis in lysolecithin-treated cells using sugar nucleotides as glycosyl donors

The 3T3 cells were treated with 50 mu g/ml lysolecithin (LL) followed by the addition of exogenously supplied radiolabelled sugar nucleotides to serve as direct glycosyl donors. These were found to be 1.5 to 3.0 times more active than untreated cells in their glycosyl transferase activities depending on the particular sugar nucleotide used. Mannosyl transferase activity was not inhibited by 2-deoxyglucose or mannose-1-phosphate, indicating that the sugar nucleotide remained intact throughout the assay period. Preincubation of the cells with tunicamycin caused an 85% decrease in mannosyl transfer, which suggested that the normal pathway of glycosylation via lipid intermediates was still operable in the treated cells. Fractionation of control and LL-treated cells after incubation with UDP[3H]galactose revealed that only microsomal and cytosolic proteins from the treated cells were radioactive. Thus, intracellular labelling of permeabilized cells was allowed. About 80% of the radiolabeled product was glycoprotein in nature, based upon its solubilization with pronase.

Absence of renal sodium adaptation in chronic renal failure

A patient with advanced chronic renal failure secondary to polycystic kidney disease suffered an episode of volume contraction during which his urinary sodium concentration fell to less than 5 mEq daily. Urine sodium excretion remained at this level when later in his course he became clinically volume expanded. The patient also suffered from Crohn's disease and had an ileostomy from which he excreted from 100 to 150 mEq sodium daily. We propose that this patient's capacity to produce urine virtually free of sodium despite advanced renal failure was a result of the persistent loss of sodium from his ileostomy. This sodium loss obviated the development of the adaptive natriuresis that usually occurs in the functioning nephrons of the diseased kidney and prevented the development of a 'salt-losing' tendency.

Paramyxo-like virus infection in a rock rattlesnake

A rock rattlesnake (Crotalus lepidus) with a history of progressive central nervous disease was submitted for necropsy. The histopathologic findings included evidence of interstitial pneumonia, multifocal areas of gliosis in the brain, and ballooning degeneration and demyelination of brainstem and upper spinal cord axons. By electron microscopy, brainstem tissue was found to contain numerous virus particles in the extracellular spaces. A paramyxo-like virus, isolated in viper heart cells from lung tissue, was observed by electron microscopy to be similar in size and shape to the particles seen in nerve tissue.

Nonpineal melatonin in the alligator (Alligator mississippiensis)

All living and most fossil representatives of the reptilian subclass Archosauria lack pineal bodies. Arrhythmic, low-level, nonpineal melatonin is present, however, in the blood of Alligator mississippiensis. Although pineal bodies have been implicated in circadian phenomena, these results suggest that arrhytmic melatonin in alligators may not be involved incircadian events and indicate that the pineal is not the only source of the hormone melatonin. The evolutionary loss of the pineal in Archosauria occurred during the Mesozoic, and era noted for its seasonal stability. Arrhythmic melatonin titers inalligators and pineal loss in alligators and other archosaurs may be related to Mesozoic seasonal stability.

False-positive hemagglutination inhibition tests for pregnancy with tubo-ovarian abscess

A 21% incidence of false-positive hemagglutination inhibition tests for pregnancy associated with tubo-ovarian abscess is described. Five illustrated cases and the causes for such false-positive reactions are discussed. Substances generated by pelvic inflammatory masses may interfere with immunologic assays for pregnancy, resulting in misdiagnosis or inappropriate management.

Cystine reductase in the dimorphic fungus Histoplasma capsulatum

Organo-sulfur compounds favor the transition of mycelia of Histoplasma capsulatum to the yeast form (6, 8). Investigation of the role of cystine in the transition revealed that the two phases concentrated this amino acid at comparable rates and that mutants defective in the uptake of cystine were still able to undergo the transition normally. Uptake of cystine is therefore probably not a requirement for transition to or maintenance of the yeast phase. Both phases contained a reduced nicotinamide adenine dinucleotide phosphate-dependent glutathione reductase; but a reduced nicotinamide adenine dinucleotide-dependent cystine reductase was detectable only in the yeast phase. The cystine reductase appeared early in the transition of mycelium to yeast. Treatment of mycelia with p-chloromercuriphenylsulfonic acid, which prevented the transition to yeast, had no effect on cystine uptake but strongly inhibited the cystine reductase. These results suggest that cystine reductase may provide reduced sulfhydryl groups involved in the transition of mycelium to yeast.

Suspected lead toxicosis in a bald eagle

An immature bald eagle (Haliaeetus leucocephalus) was submitted to the University of Maryland, College Park, for clinical examination. The bird was thin, had green watery feces, and was unable to maintain itself in upright posture. Following radiography, the bird went into respiratory distress and died. Numerous lead shot were recovered from the gizzard, and chemical analysis of liver and kidney tissue revealed 22.9 and 11.3 ppm lead, respectively. The clinical signs, necropsy findings, and chemical analysis of the eagle were compatible with lead toxicosis.