Detection of Trypanosoma cruzi and Trypanosoma rangeli infection by duplex PCR assay based on telomeric sequences

We used the species specificity and repetitious nature of subtelomeric kinetoplastida sequences to generate a duplex PCR assay for the simultaneous detection of Trypanosoma cruzi and Trypanosoma rangeli in experimentally and naturally infected triatomine (Reduviid) bugs and in infected human subjects. The assay was species specific and was capable of detecting 1/20th of T. cruzi and 1/4th of T. rangeli cell equivalents without complementary hybridization. In addition, the PCR-based assay was robust enough for direct application to difficult biological samples such as Reduviid feces or guts and was capable of recognizing all T. cruzi and T. rangeli strains and lineages. Because the assay primers amplify entirely different target sequences, no reaction interference was observed, facilitating future adaptation of this assay to an automated format.     

Purine nucleoside phosphorylase deficiency: a new case report and identification of two novel mutations (Gly156A1a and Val217Ile), only one of which (Gly156A1a) is deleterious

Purine nucleoside phosphorylase (PNP) deficiency results in an autosomal recessive immunodeficiency disease characterized by initial involvement of cellular immunity and neurological manifestations with subsequent abnormalities of humoral immunity. The initial presentation and clinical course has varied widely in the relatively few published cases. The molecular basis has been reported in only 10 patients, precluding evaluation of phenotype-genotype relationships. We now report clinical, immunologic, and molecular findings in a new case of relatively early onset that emphasizes hypotonia and developmental delay as early manifestations. The patient carried two novel missense mutations (Gly56A1a and Val217Ile) on the same allele in apparent homozygosity. Expression of each of the mutant enzymes in vitro demonstrated that the Gly156A1a mutation abolished enzyme activity while the Val217Ile mutation was without obvious effect and is therefore a normal variant. Such "normal" polymorphisms might be associated with a variable response to the immunosuppressive PNP inhibitors currently in clinical trials.     

A phase I and pharmacokinetic trial of terephthalamidine (NSC 57155) as a 120-hour continuous infusion

In this phase I study, terephthalamidine was administered as a 120-hour continuous infusion repeated every 21 days. Thirteen patients received 27 courses of terephthalamidine at four dose levels (14, 28, 46, and 70 mg/m²/day). Dose-limiting toxicity consisted of profound and intractable anorexia, weight loss and prostration in all patients. Toxicity was delayed and accompanied by hyponatremia and hypokalemia. No hematologic or other toxicity was documented. One patient with adenocarcinoma of the lung had a 40% decrease in mediastinal lymph nodes and resolution of a pleural effusion lasting 2 months. Pharmacokinetic analysis by HPLC was performed in all patients during their first course. The harmonic mean terminal half-life for terephthalamidine was 23 hours with a plasma clearance of 1.7 l/hr/m². Both plasma concentrations achieved during infusion (r² = 0.9) and area under the curve (AUC) (r² = 0.8) were proportional to increase in dose (p < 0.002). Renal excretion accounted for 64% of the total cumulative dose, with an average renal clearance of 1.16 l/hr/m². Due to the unacceptable toxicity seen at all doses with this schedule, no further studies are recommended unless the mechanism of toxicity is better understood and can be prevented.     

THE HYDROLYSIS OF HYALURONIC ACID BY BACTERIAL ENZYMES

An improved method is described for preparing the enzyme which hydrolyzes the polysaccharide acid contained in vitreous humor, umbilical cord, synovial fluid, and the mucoid phase of group A hemolytic streptococci. Preparations have been obtained from pneumococci, group A hemolytic streptococci, Clostridium welchii, and from splenic tissue, which display the same specific activity. Evidence is presented to show that the hydrolytic enzyme is not the same as that responsible for the lysis of pneumococci. In pneumococci and hemolytic streptococci the major portion of the enzyme is bound to the cell structure. The enzyme from Clostridium welchii is associated with other carbohydrate-splitting enzymes in the culture medium and not with the bacterial cells. It is suggested that the disappearance of the mucoid capsule of group A hemolytic streptococci is due to enzymatic hydrolysis of the acid polysaccharide. The relation between enzyme activity and the virulence and invasiveness of group A hemolytic streptococci is briefly considered.