Evaluation of the efficacy of albendazole against the larvae of Taenia solium in experimentally infected pigs, and kinetics of the immune response

Cysticercosis, a disease of economic and public health importance, is caused by Cysticercus cellulosae, the metacestode stage of Taenia solium. Experimental induction of cysticercosis was achieved in young pigs by feeding an optimum dose of 20,000 T. solium (Indian strain) eggs after immunosuppression, to assess the effect of albendazole and development of the immune response to cysticercus antigens before and after treatment.

Histopathological studies revealed the presence of cysticerci in liver, lungs and muscles. Treatment with albendazole at 15 mg kg⁻¹ body weight daily for 30 days starting from day 0 or 15 days post-infection resulted in 100% cure rates. Increases in antibody titre to crude soluble extract and a Sephadex G-200 purified antigenic fraction of Cysticercus cellulosae were found on days 25, 40 and 55 post-infection in untreated pigs and those in which treatment started on day 15 post-infection, whereas no increase in antibody response was observed in pigs in which treatment started on day 0.     

Physicochemical characterization and in vitro interaction with brain capillary endothelial cells of artificially monoacylated ribonucleases A

Acylated proteins play a crucial role in cellphysiology because of their increased interaction withmembranes. Their isolation is difficult as aconsequence of their low cellular concentration andtheir chemical preparation is problematic due tosolubility problems. Through the use of reversedmicelles, we produced tens of milligrams of acylatedribonucleases A, chosen as a model, purified them bysemi-preparative high performance liquidchromatography (HPLC) and characterized them by analyticalHPLC, capillary electrophoresis, mass spectrometry, peptide mapping, Edman degradation and enzyme activity. We nextscrutinized the interaction with an in vitro blood–brainbarrier model and demonstrated that palmitoylated andstearoylated ribonucleases A are transported from onecompartment to the other across the cellular monolayer,in contrast to the native enzyme.     

Long-Term Drug Treatment of Obesity in a Private Practice Setting

ATKINSON, RICHARD L, ROY C BLANK, DONALD SCHUMACHER, NIKHIL V DHURANDHAR, DOUGLAS L RITCH. Long-term drug treatment of obesity in a private practice setting. This study evaluated the long-term efficacy and safety of the combination of phentermine and fenfluramine for the treatment of obesity in a private practice setting. A total of 1388 consecutive, qualified patients presenting to a private general internal medicine practice in Charlotte, NC, were enrolled with eligibility criteria including: age 18 years to 60 years, 20% over “desirable” bodyweight or body mass index <27, no serious medical or psychiatric disease, and no contraindications to drug therapy. Patients were instructed in diet, exercise, and behavior modification techniques and received phentermine (15 mg/day to 30 mg/day) and fenfluramine (20 mg/day to 60 mg/day) continuously for over 3 years. Average duration of treatment was 15. 9 months, and average weight loss at the last visit was 11. 6 kg, or 11. 7% of initial bodyweight. For patients completing 1 year of drug treatment, mean weight loss was 16. 5 kg, or 16% of initial weight. Weight loss persisted for 2 years, but partial regain was seen at 3 years. The dropout rates were 18% at 6 months, 39% at 1 year, 68% at 2 years, and 78% at 3 years. At 1 year, blood pressure of hypertensive patients fell from 151/95 mm Hg to 127/78 mm Hg, and serum cholesterol and triglycerides of hyperlipidemic patients fell by 0. 750 mmol/L (29 mg/dL) and 0. 937 mmol/L (83 mg/dL), respectively. Adverse events were modest. We conclude that, in a private practice setting, long-term treatment of obesity with the combination of phentermine, fenfluramine, and a weight maintenance program is generally safe and effective. More research is needed to determine efficacy and safety for longer than 3 years.     

Therapy of bovine ocular squamous-cell carcinoma with local doses of interleukin-2: 67% complete regressions after 20 months of follow-up

We have tested the therapeutic potency of peritumorally injected low doses of interleukin-2(IL-2). Seventy tumours of the bovine ocular squamous-cell carcinoma (BOSCC), 1–3 cm in diameter, were treated with 5000, 20 000 or 200 000 U IL-2 from Eurocetus (Chiron) to find the optimal dose for treatment. Injections were given peritumorally on Monday to Friday on 2 consecutive weeks. The size of the tumours was measured before treatment and 1, 3, 4, 9 and 20 months after treatment. After 9 months complete regression was observed in 89% of the tumours treated with 5000 U IL-2, 80% treated with 20 000 U and 67% treated with 200 000 U. After 20 months, there was complete regression of 35%, 31% and 67% of the tumours respectively. The 9-and 20-month results of the 200 000-U treatment are significantly better than those of the 5000-U and 20 000-U treatments taken together. This protocol may be useful to treat advanced inoperable tumours (e.g. of the nasopharynx or skin) of human patients.     

Effects of lethal irradiation and cyclosporin A treatment on the growth and tumoricidal activity of a T cell clone potentially useful in cancer therapy

The TALL-104 cell line, originally derived from a patient with T cell leukemia, can be maintained indefinitely in culture in the presence of interleukin-2 (IL-2) and is endowed with a highly potent major-histocompatibilitycomplex (MHC)-non-restricted tumoricidal activity both in vitro and in animal models. The present study analyzes in detail the short- and long-term effects of irradiation and cyclosporin A (CsA) treatment on the growth and tumoricidal function of this T cell clone as compared to polyclonal lymphokine-activated killer (LAK) cell preparations from healthy donors. DNA and RNA syntheses by both TALL-104 and LAK cells were irreversibly arrested a few hours after irradiation with 40 Gy. However, 4-h⁵¹Cr-release assays, performed on different days (day 1 to day 7) after irradiation, showed that the cytotoxic efficiency of TALL-104 cells against hematopoietic and solid tumor targets was only modestly reduced, whereas that of LAK cells was severely inhibited. Moreover, the cytotoxic responses to recombinant human IL-2 and IL-12, measured 18 h after irradiation and cytokine addition, were normal in the case of TALL-104 cells but were abolished in the case of LAK cells. Co-culture of IL-2-or IL-12-preactivated TALL-104 cells with a tumor target for 5 days in the absence of cytokines resulted in a lower efficiency of lysis, as compared to the non-irradiated effectors, especially if the initial stimulus was IL-12. These findings suggest the requirement of multiple cytokine stimulation for optimal expression of tumoricidal activity by lethally irradiated TALL-104 cells. CsA, while abrogating TALL-104 cell proliferation at the low dose of 0.5 g/ml, inhibited their cytotoxic function marginally only at high doses (100 g/ml). By contrast, CsA reduced dose-dependently the cytotoxicity of LAK cells starting at very low doses (0.5 g/ml). CsA did not impair the ability of TALL-104 and LAK cells to produce interferon (IFN), tumor necrosis factor (TNF) , and granulocyte/macrophage-colony-stimulatory factor (GM-CSF) in response to IL-2, IL-12, or tumor targets. Irradiation reduced drastically IFN production by LAK, but not TALL-104 cells; release of TNF and GM-CSF by either type of effector was inhibited by 10%–50%, depending on the stimulus. The high resistance of the TALL-104 cells' tumoricidal function to irradiation and immunosuppressive drugs renders this immortal T cell clone a potentially safe and effective reagent for new adoptive-transfer approaches to cancer in MHC-incompatible recipients.     

Transfer and expression of the human multiple drug resistance gene as potential human gene therapy

The human multiple drug resistance (MDR) gene has been used as a model for human gene transfer which could lead to human gene therapy. MDR is a transmembrane protein which pumps a number of toxic substances out of cells including several drugs used in cancer chemotherapy. Normal bone marrow cells express low levels of MDR and are particularly sensitive to the toxic effects of these drugs. There are two general applications of MDR gene therapy: (1) to provide drug-resistance to the marrow of cancer patients receiving chemotherapy, and (2) as a selectable marker which when co-transferred with a non-selectable gene such as the human beta globin gene can be used to enrich the marrow for cells containing both genes. We demonstrate efficient transfer and expression of the human MDR gene in a retroviral vector into live mice and human marrow cells including CD34⁺ cells isolated from marrow and containing the bulk of human hematopoietic progenitors. MDR gene transduction corrects the sensitivity of CD34⁺ cells to taxol, an MDR drug substrate, and enriches the marrow for MDR-transduced cells. The MDR gene-containing retroviral supernatant used has been shown to be safe and free of replication-competent retrovirus. Because of the safety of the MDR retroviral supernatant, and efficient gene transfer into mouse and human marrow cells, a phase 1 clinical protocol for MDR gene transfer into cancer patients has been approved to evaluate MDR gene transfer and expression in human marrow.     

Schistosoma haematobium: Amoscanate and adult worm ultrastructure

Amoscanate, when administered orally as an aqueous or “formulated” preparation, induced pronounced ultrastructural abnormalities in male and female Schistosoma haematobium. Higher dose levels of the aqueous suspension (300 mg/kg body wt) had to be administered to achieve the full range of effects induced by formulated doses of 2.5–8 mg/kg body wt. Worms were recovered from hamsters between 1 and 120 hr after treatment. Although the amount of amoscanate-induced damage varied considerably between worms, an overall pattern of damage emerged. Initially, 1 hr after treatment, amoscanate caused tegumental vacuolation and oedema. As the drug treatment period was extended to 24 hr, blebbing, exudation, collapse of sensory organelle bases, and abnormal mitochondria became increasingly evident. With exposure to higher drug doses (50–300 mg/kg body wt), the tegument became further distorted with the appearance of necrotic structures and myelin whorls, which appeared to represent various stages in lysosomal formation and digestion. Eventually, erosion of surface layers resulted in the breakdown of tegumental integrity. The caeca and vitellaria were also adversely affected by drug treatment. Basal vacuolation and the formation of myelin whorls occurred in the gastrodermis. In the mature S4 vitelline cells, coalesced vitelline droplets and myelin whorls were evident.     

D-amphetamine-induced hypothermia and hypermotility in rats: Changes after systemic administration of beta-endorphin

Systemically administered beta-endorphin was tested in rats for its ability to modify the hypothermia and hypermotility induced by d-amphetamine. Colonic temperature and motor activity were measured in a cold (4°C) ambient temperature in animals given IP injections of beta-endorphin (0.1, 1.0, or 3.0 mg/kg), naloxone (10 mg/kg), or morphine (30 mg/kg). The same measurements were taken in animals given beta-endorphin (1.0 mg/kg) in combination with naloxone or saline pretreatment and d-amphetamine (15 mg/kg) or saline post-treatment. Morphine alone had a biphasic effect on thermoregulation, but did not affect d-amphetamine-induced hypothermia. Activity scores were decreased by morphine, in both d-amphetamine and saline treated animals. The thermal response of rats to beta-endorphin alone was variable, depending on dosage, but all 3 dosages partially blocked the hypothermic effect of d-amphetamine. Naloxone blocked the thermal effects of both beta-endorphin and d-amphetamine. Motor activity tended to be decreased by naloxone, regardless of amphetamine treatment, but beta-endorphin tended to increase activity in amphetamine-treated animals and reduce it in saline-treated controls. In their actions on both thermoregulation and activity, naloxone and beta-endorphin appeared to interact independently with d-amphetamine, often producing effects in the same direction, but in combination, they tended to be mutually inhibitory.     

Trypanosoma brucei: Maintenance of concentrated suspensions of bloodstream trypomastigotes in vitro using continuous dialysis for measurement of endocytosis

A continuous dialysis technique capable of maintaining concentrated suspensions of bloodstream Trypanosoma brucei (up to 4 × 10⁸/ml) at 25 C for 2 hr without loss of viability has been developed in order to measure endocytosis under controlled conditions in vitro. Using this technique, the kinetics and mechanism of uptake of the metabolically inert macromolecule, ¹²⁵I-labelled polyvinylpyrrolidone (¹²⁵I-PVP), have been investigated. Binding to the plasma membrane and the rate of uptake of ¹²⁵I-PVP from the extracellular medium by the trypanosome are both decreased by the addition of unlabelled PVP and human serum albumin. A mechanism for uptake of ¹²⁵I-PVP by a combination of fluid-phase and adsorptive endocytosis from the flagellar pocket of the trypanosome is proposed. In the presence of serum albumin and unlabelled PVP, endocytosis of ¹²⁵I-PVP occurs in the fluid phase only, with endocytic indices of 14.5 ± 0.9 and 54.1 ± 11.3 nl/hr/mg protein in vitro at 25 C and in vivo at 37 C, respectively.