Dystrophin gene mutation location and the risk of cognitive impairment in Duchenne muscular dystrophy.

Background: A significant component of the variation in cognitive disability that is observed in Duchenne muscular dystrophy (DMD) is known to be under genetic regulation. In this study we report correlations between standardised measures of intelligence and mutational class, mutation size, mutation location and the involvement of dystrophin isoforms.

Methods And Results: Sixty two male subjects were recruited as part of a study of the cognitive spectrum in boys with DMD conducted at the Sydney Children's Hospital (SCH).

Measurement of the clinical utility of a combined mutation detection protocol in carriers of Duchenne and Becker muscular dystrophy.

Background: Recent methodological advances have improved the detection rate for dystrophin mutations, but there are no published studies that have measured the clinical utility of these protocols for carrier detection compared with conventional carrier testing protocols that use pedigree, serum creatine kinase levels and linkage analysis.

Methods And Subjects: The clinical utility of a combined mutation detection protocol was measured. It involved quantitative PCR procedures followed by DNA sequence analysis for the identification of dystrophin mutation carriers in 2101 women at risk of being carriers from 348 mutation-known Duchenne or Becker muscular dystrophy pedigrees.

Menadione kills trophozoites and cysts of Giardia intestinalis.

Production of reactive oxygen species by redox cycling in the presence of low levels of oxygen has been studied as a possible approach to anti-protozoal chemotherapeutic strategy. Incubation of the diplomonad flagellate Giardia intestinalis with 2-methy-1,4-naphthoquinone (menadione), under anaerobic conditions, gave UV absorption changes characteristic of reduction to menadiol; partial reversal was observed on admitting O(2). Under microaerobic conditions, similar to those on the surface of the jejunal mucosa, trophozoites consumed O(2) rapidly in the presence of menadione; reaction products included singlet O(2) (monitored by single photon counting of O(2)-dependent low-level chemiluminescence) and H(2)O(2) (measured by the formation of Complex I of microperoxidase).

Osmoregulation in the parasitic protozoan Tritrichomonas foetus.

Tritrichomonas foetus was shown to undergo a regulatory volume increase (RVI) when it was subjected to hyperosmotic challenge, but there was no regulatory volume decrease after hypoosmotic challenge, as determined by using both light-scattering methods and measurement of intracellular water space to monitor cell volume. An investigation of T. foetus intracellular amino acids revealed a pool size (65 mM) that was similar to that of Trichomonas vaginalis but was considerably smaller than those of Giardia intestinalis and Crithidia luciliae.

The "primitive" microaerophile Giardia intestinalis (syn. lamblia, duodenalis) has specialized membranes with electron transport and membrane-potential-generating functions.

Here it is shown that the flagellated protozoon Giardia intestinalis, commonly regarded as an early branching eukaryote because of its lack of mitochondria, has membraneous structures that partition the cationic, membrane-potential-sensitive fluorophore rhodamine 123. This organism also reduces a tetrazolium fluorogen at discrete plasma-membrane-associated sites. That these functions occur in distinctive specialized membrane systems supports the growing evidence that G.

The microaerophilic flagellate Giardia intestinalis: oxygen and its reaction products collapse membrane potential and cause cytotoxicity.

Trophozoites of the microaerophilic flagellate parasitic protozoon Giardia intestinalis have only a limited capacity to detoxify O(2). Thus, when exposed to controlled concentrations of dissolved O(2) >8 microM, they gradually lose their ability to scavenge O(2). In a washed cell suspension stirred under 10% air in N(2) (equivalent to 25 microM O(2)), inactivation of the O(2)-consuming system was complete after 3.