Stimulation of dopamine synthesis and release by morphine and D-Ala2-D-Leu5-enkephalin in the mouse striatum in vivo

The effects of opiates on dopamine (DA) release and synthesis were assessed in the mouse striatum $\text{in vivo}$ by simultaneously measuring 3,4-dihydroxyphenylalanine (DOPA) and 3,4-dihydroxyphenylacetic acid (DOPAC) levels after inhibition of aromatic amino acid decarboxylase. This method was developed to assess stimulus-coupled changes in DA synthesis and release. Peripheral injections of morphine and intraventrcular injections of D-Ala²-Leu⁵-enkephalin elevated DOPAC levels, indicating that “opiates” stimulated DA release. Concomitantly, the rate of DA synthesis was increased. The effects were dose-dependent, saturable and antagonized by naloxone. When morphine and the enkephalin analog were given together in saturating doses, the effects of the two agents were not additive. Thus, the involvement of different receptors in the mediation of the effects of morphine and enkephalins could not be demonstrated.     

Endogenous opiates inhibit gastric acid secretion induced by central administration of Thyrotropin-Releasing Hormone (TRH)

Thyrotropin-releasing hormone (TRH) administered intraventricularly (ICV) to rats causes a dose-dependent increase in gastric acid secretion over a range of 0.01 μg to 10 μg in the pyloris ligated rat. The maximum increase in gastric acid secretion occurs in the first hour. This effect of TRH is not mediated by its metabolites, histidyl-proline diketopiperazine or pyroglutamyl-histidyl-proline (acid TRH). β-endorphin, D-alanine-methionine-enkephalin and the leucine-enkephalin precursor, dynorphin, all inhibit TRH-induced gastric acid secretion. Bombesin, which reduces basal gastric acid secretion had no effect on TRH-induced secretion.     

Hydrolysis of Galactose from Glycolipids and Glycoprotein by Young Rat Brain β-Galactosidases Immobilized to Sepharose 4B

An extract of glycosidic enzymes from young rat brain was immobilized to cyanogen bromide-activated Sepharose 4B. Most glycosidases retained approximately 10-25% of their activities after immobilization. Immobilized β-galactosidases were used repeatedly without detectable loss of enzyme activity in the hydrolysis of p-nitrophenyl-β-d -galactopyranoside. In addition to the synthetic substrate, the immobilized rat brain β-galactosidases could also hydrolyze galactose from lactose, galactosylcerebroside, asialofetuin, and GM₁-ganglioside. The hydrolysis of GM₁- to GM₂-ganglioside was confirmed on TLC.     

Selective isolation and culture of a proliferating epithelial cell population from the hamster trachea

Summary A reliable cell isolation technique was developed to allow the cultivation of cells from the hamster respiratory tract. Repeated thermolysin treatments and gradient centrifugation yielded a cell culture completely free from contamination by fibroblasts. Viable cells could be isolated from as little tissue as a single hamster trachea, but in vitro proliferation occurred only if the hamster was less than 4 months of age. The cultured cells could be repeatedly passaged and subcultured for weeks by employing normal tissue culture techniques. Morphologically, the monolayers appeared to be a homogeneous population of epithelial cells, and successful cloning of freshly isolated single cells resulted in apparently identical cultures. The epithelial origin of these cells was also suggested by continued growth in minimum essential medium withd-valine substituted forl-valine. The relative ease with which this cell type can be isolated, cultured, and manipulated in vitro should encourage its application as a model of the respiratory epithelium. This research was supported by Public Health Service Grant P50-HL 19171 and Research Career Development Award 1-K04-AI 00178 to J. B. B.     

The influence of coal ash and thermal discharges upon the distribution and bioaccumulation of aquatic invertebrates

The distribution, density and uptake of twenty elements by aquatic invertebrates inhabiting a drainage system, that received excessive coal ash effluent (275 JTU of turbidity) at one end and thermal loading (44.5°C) at the other end, was studied for 15 months. The ash settling basin filled during the first eight months of sampling which resulted in the release of ash effluent directly into the receiving system. Density of invertebrates was lowest in the 300 m stream between the ash basin and swamp and highest 1200 m beyond the stream-swamp confluence where ash influence was minimal. Invertebrate density was lowest in the stations where turbidity from ash effluent was greatest. The most tolerant invertebrates to coal ash stress were odonates (Libellula sp. and Enallagma sp.), crayfish (Procambarus sp.), amphipods (Gammarus sp.) and gastropods (Physa. sp.), and midges (Chironomidae) when the basin was filling. During the period of ash overflow, all groups were either reduced in numbers or absent. In the thermally stressed station, Libellula sp. was the predominant invertebrate sampled when water temperature ranged from 25.5–45.5°C (257-1=28.7°C) all aquatic invertebrates were limited in numbers and density when temperature exceeded the lower and upper ranges of 10.0–38.0°C.This research was supported by AEC Contract AT (38-1-824)This research was supported by AEC Contract AT (38-1-824)     

Evaluation of fasciotomy and vasodilator for treatment of frostbite in the dog

Severe freezing injury was produced in the hind foot of 26 mongrel dogs. All dogs were given daily whirlpool treatment and protective bandaging for 14 days following injury. In addition, certain dogs received a vasodilator, fasciotomy, or both vasodilator and fasciotomy following injury. Deep foot temperatures, foot volumes, tissue pressures, and 14 day tissue loss-salvage scores were compared. Significant differences between fasciotomy and nonfasciotomy dogs were seen in foot temperature, volume, and tissue pressure immediately following fasciotomy. Though there was no significant difference in 14 day tissue loss, there was clinically apparent prolongation of integrity of the local vascular system for 2 to 5 days following fasciotomy, and total foot salvage in several dogs receiving fasciotomy.     

A silicone polymer as a Steroid Reservoir for enzyme-catalyzed Steroid reactions

Since steroids are only slightly soluble in the aqueous solutions in which enzymatic reactions take place, it is difficult to obtain high effective concentrations per unit reactor volume when enzymes are used to catalyze steroid reactions. In order to obtain high effective concentrations in the present work, we have used small particles of a hydrophobic polymer, poly (dimethyl siloxane), as a reservoir for the steroid substrate and product. The activity of a bacterial hydroxysteroid dehydrogenase in a buffer solution declines much more slowly in the presence of those polymer particles than in the presence of a comparable amount of butyl acetate or ethyl acetate, the organic solvents used as steroid reservoirs in previous work with steroid transforming enzymes. When another substrate of the hydroxysteroid dehydrogenase is loaded into the polymer particles and the particles are suspended in an aqueous solution containing the enzyme and its cofactor, more product is formed that when a similar solution is emulsified with butyl acetate.     

Interaction of charged lipid vesicles with planar bilayer lipid membranes: Detection by antibiotic membrane probes

A technique has been developed for monitoring the interaction of charged phospholipid vesicles with planar bilayer lipid membranes (BLM) by use of the antibiotics Valinomycin, Nonactin, and Monazomycin as surface-charge probes. Anionic phosphatidylserine vesicles, when added to one aqueous compartment of a BLM, are shown to impart negative surface charge to zwitterionic phosphatidylocholine and phosphatidylethanolamine bilayers. The surface charge is distributed asymmertically, mainly on the vesicular side of the BLM, and is not removed by exchange of the vesicular aqueous solution. Possible mechanisms for the vesicle-BLM interactions are discussed.     

Pyronaridine–artesunate real-world safety,tolerability, and effectiveness in malaria patients in 5 African countries: A single-arm,open-label,cohort event monitoring study

BackgroundIn Phase II/III randomized controlled clinical trials for the treatment of acute uncomplicated malaria, pyronaridine–artesunate demonstrated high efficacy and a safety profile consistent with that of comparators, except that asymptomatic, mainly mild-to-moderate transient increases in liver aminotransferases were reported for some patients. Hepatic safety, tolerability, and effectiveness have not been previously assessed under real-world conditions in Africa.Methods and findingsThis single-arm, open-label, cohort event monitoring study was conducted at 6 health centers in Cameroon, Democratic Republic of Congo, Gabon, Ivory Coast, and Republic of Congo between June 2017 and April 2019. The trial protocol as closely as possible resembled real-world clinical practice for the treatment of malaria at the centers. Eligible patients were adults or children of either sex, weighing at least 5 kg, with acute uncomplicated malaria who did not have contraindications for pyronaridine–artesunate treatment as per the summary of product characteristics. Patients received fixed-dose pyronaridine–artesunate once daily for 3 days, dosed by body weight, without regard to food intake. A tablet formulation was used in adults and adolescents and a pediatric granule formulation in children and infants under 20 kg body weight. The primary outcome was the hepatic event incidence, defined as the appearance of the clinical signs and symptoms of hepatotoxicity confirmed by a >2× rise in alanine aminotransferase/aspartate aminotransferase (ALT/AST) versus baseline in patients with baseline ALT/AST >2× the upper limit of normal (ULN). As a secondary outcome, this was assessed in patients with ALT/AST >2× ULN prior to treatment versus a matched cohort of patients with normal baseline ALT/AST. The safety population comprised 7,154 patients, of mean age 13.9 years (standard deviation (SD) 14.6), around half of whom were male (3,569 [49.9%]). Patients experienced 8,560 malaria episodes; 158 occurred in patients with baseline ALT/AST elevations >2×ULN. No protocol-defined hepatic events occurred following pyronaridine–artesunate treatment of malaria patients with or without baseline hepatic dysfunction. Thus, no cohort comparison could be undertaken. Also, as postbaseline clinical chemistry was only performed where clinically indicated, postbaseline ALT/AST levels were not systematically assessed for all patients. Adverse events of any cause occurred in 20.8% (1,490/7,154) of patients, most frequently pyrexia (5.1% [366/7,154]) and vomiting (4.2% [303/7,154]). Adjusting for Plasmodium falciparum reinfection, clinical effectiveness at day 28 was 98.6% ([7,369/7,746] 95% confidence interval (CI) 98.3 to 98.9) in the per-protocol population. There was no indication that comorbidities or malnutrition adversely affected outcomes. The key study limitation was that postbaseline clinical biochemistry was only evaluated when clinically indicated.ConclusionsPyronaridine–artesunate had good tolerability and effectiveness in a representative African population under conditions similar to everyday clinical practice. These findings support pyronaridine–artesunate as an operationally useful addition to the management of acute uncomplicated malaria.Trial registrationClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT03201770","term_id":"NCT03201770"}}NCT03201770.

Gaston Tona Lutete and co-workers report on safety and effectiveness of the antimalarial drug pyronaridine-artesunate in African countries.