Effect of Farnesyltransferase Inhibitor R115777 on Mitochondria of Plasmodium falciparum

The parasite Plasmodium falciparum causes severe malaria and is the most dangerous to humans. However, it exhibits resistance to their drugs. Farnesyltransferase has been identified in pathogenic protozoa of the genera Plasmodium and the target of farnesyltransferase includes Ras family. Therefore, the inhibition of farnesyltransferase has been suggested as a new strategy for the treatment of malaria. However, the exact functional mechanism of this agent is still unknown. In addition, the effect of farnesyltransferase inhibitor (FTIs) on mitochondrial level of malaria parasites is not fully understood. In this study, therefore, the effect of a FTI R115777 on the function of mitochondria of P. falciparum was investigated experimentally. As a result, FTI R115777 was found to suppress the infection rate of malaria parasites under in vitro condition. It also reduces the copy number of mtDNA-encoded cytochrome c oxidase III. In addition, the mitochondrial membrane potential (DeltaPsim) and the green fluorescence intensity of MitoTracker were decreased by FTI R115777. Chloroquine and atovaquone were measured by the mtDNA copy number as mitochondrial non-specific or specific inhibitor, respectively. Chloroquine did not affect the copy number of mtDNA-encoded cytochrome c oxidase III, while atovaquone induced to change the mtDNA copy number. These results suggest that FTI R115777 has strong influence on the mitochondrial function of P. falciparum. It may have therapeutic potential for malaria by targeting the mitochondria of parasites.

Dexmedetomidine Preconditioning Attenuates Cisplatin-Induced Ototoxicity in Zebrafish

OBJECTIVES: Utilisation of high-frequency drills is known to increase noise induced hearing loss due to increasing the damages of inner ear cells. This study aimed to investigate whether preconditioning by using dexmedetomidine (DEX) decreased the occurrence of ischemia in inner cells of the ear. METHODS: We utilised a transgenic zebrafish line Brn3C, and the embryos were collected from breeding adult zebrafish. Five-day-old larvae were cultured at the density of 50 embryos, and the larvae were classified into 4 groups: control, cisplatin group, DEX group, and DEX+yohimbine; adrenoreceptor blocker group. The DEX group was categorised into 3 subgroups by dosage; 0.1, 1, and 10 microM. Preconditioning was performed for 150 minutes and then exposed to cisplatin for 6 hours. The experiment was performed in 7 replicates for each group and the number of hair cells in 3 parts of the neuromasts of each fish was determined. RESULTS: Hair cell apoptosis by cisplatin was attenuated more significantly in the DEX preconditioning group than in the control group. However, the preconditioning effects were not blocked by yohimbine. CONCLUSION: The results of this study suggest that hearing loss caused by vibration-induced noise could be reduced by using DEX and may occur through other mechanisms rather than adreno-receptors.

Detection of Heparin in the Salivary Gland and Midgut of Aedes togoi

Mosquitoes secrete saliva that contains biological substances, including anticoagulants that counteract a host's hemostatic response and prevent blood clotting during blood feeding. This study aimed to detect heparin, an anticoagulant in Aedes togoi using an immunohistochemical detection method, in the salivary canal, salivary gland, and midgut of male and female mosquitoes. Comparisons showed that female mosquitoes contained higher concentrations of heparin than male mosquitoes. On average, the level of heparin was higher in blood-fed female mosquitoes than in non-blood-fed female mosquitoes. Heparin concentrations were higher in the midgut than in the salivary gland. This indicates presence of heparin in tissues of A. togoi.

Cognition Associated with Dystrophin Deletion in Duchenne Muscular Dystrophy

OBJECTIVE: To find correlations between the deletion of dystrophin gene and cognitive status in Duchenne muscular dystrophy (DMD). METHOD: Cognitive abilities of 49 DMD children with dystrophin deletion were tested. Korean Wechsler Intelligence Scale for children was used to evaluate the cognitive status in DMD. Gene deletion was classified into two groups according to the location of the rearrangement (proximal region: central and 3' region of the gene). RESULTS: Molecular study by multiplex PCR (Polymerase Chain Reaction) of dystrophin exons was performed to identify 49 deletions in the 110 DMD patients. 13 out of 49 DMD were mentally impaired. In patients with distal deletions, total IQ (Intelligence Quotient) score was lower than the those with proximal deletions; which was not statistically significant. And the difference of the verbal and performance intelligence scale was not statistically significant. But comparisons of molecular and neuropsychological features showed that deletions localized in the central and 3' regions of the gene were preferentially associated with the mental impairement. CONCLUSION: We concluded that deletions in the distal portions of the gene were more related to the mental retardation, although deletions with variable locations might lead to cognitive impairments.

Comparison of specific activity and cytopathic effects of purified 33 kDa serine proteinase from Acanthamoeba strains with different degree of virulence

The pathogenic mechanism of granulomatous amebic encephalitis (GAE) and amebic keratitis (AK) by Acanthamoeba has yet to be clarified. Protease has been recognized to play an important role in the pathogenesis of GAE and AK. In the present study, we have compared specific activity and cytopathic effects (CPE) of purified 33 kDa serine proteinases from Acanthamoeba strains with different degree of virulence (A. healyi OC-3A, A. lugdunensis KA/E2, and A. castellanii Neff). Trophozoites of the 3 strains revealed different degrees of CPE on human corneal epithelial (HCE) cells. The effect was remarkably reduced by adding phenylmethylsulfonylfluoride (PMSF), a serine proteinase inhibitor. This result indicated that PMSF-susceptible proteinase is the main component causing cytopathy to HCE cells by Acanthamoeba. The purified 33 kDa serine proteinase showed strong activity toward HCE cells and extracellular matrix proteins. The purified proteinase from OC-3A, the most virulent strain, demonstrated the highest enzyme activity compared to KA/E2, an ocular isolate, and Neff, a soil isolate. Polyclonal antibodies against the purified 33 kDa serine proteinase inhibit almost completely the proteolytic activity of culture supernatant of Acanthamoeba. In line with these results, the 33 kDa serine proteinase is suggested to play an important role in pathogenesis and to be the main component of virulence factor of Acanthamoeba.

Genetic diversity of Acanthamoeba isolated from ocean sediments

Genetic diversity of 18 Acanthamoeba isolates from ocean sediments was evaluated by comparing mitochondrial (mt) DNA RFLP, 18S rDNA sequences and by examining their cytopathic effects on human corneal epithelial cells versus reference strains. All isolates belonged to morphologic group II. Total of 16 restriction phenotypes of mtDNA from 18 isolates demonstrated the genetic diversity of Acanthamoeba in ocean sediments. Phylogenetic analysis using 18s rDNA sequences revealed that the 18 isolates were distinct from morphological groups I and III. Fifteen isolates showed close relatedness with 17 clinical isolates and A. castellanii Castellani and formed a lineage equivalent to T4 genotype of Byers' group. Two reference strains from ocean sediment, A. hatchetti BH-2 and A. griffini S-7 clustered unequivocally with these 15 isolates. Diversity among isolates was also evident from their cytopathic effects on human corneal cells. This is the first time describing Acanthamoeba diversity in ocean sediments in Korea.

Quality of Life in Patients with Neuromuscular Disease Using Mechanical Ventilatory Support

OBJECTIVE: To estimate the quality of lives in neuromuscular disease patients using mechanical ventilators by comparing their `Index of Well-being' reported their own and caregivers. METHOD: The Semantic Differential Scale of General Affect and Life Domain Satisfaction Measures were instruments to measure perceived well-being. They were used to survey 33 ventilator-assisted patients and their caregivers. A third instrument was devised to study the satisfaction of rehabilitative management including mechanical ventilation. RESULTS: The caregivers significantly underestimated their patients' scores in the general affect instruments and life satisfaction (p<0.05). Twenty-six of 33 responding patients (78.8%) expressed satisfaction with present rehabilitative management. CONCLUSION: The most disabled ventilator-assisted patients with neuromuscular disease rated their quality of life as satisfying. The dependence on ventilation was not a predictor of a low quality of life. But the rating of the patient's quality of life from significant others was underestimated. This was important because patients' decision making concerning ventilation care was influenced by significant others.

Clinical Influence of Emotional Depression on Chronic Low Back Pain

OBJECTIVE: To compare the patients of chronic low back pain with and without emotional depression in terms of psychosomatic aspect and clinical outcome by cross-sectional and prospective study. METHOD: We evaluated 100 patients who were admitted due to chronic low back pain. The patients were classified into three groups (moderately depressed, mild depressed, non-depressed) by the score of Beck Depression Inventory (BDI). And three groups were compared by Pain Disability Index (PDI), Visual Analogue Scale (VAS), Pain Rating Score (PRS) and special diagnostic studies such as MRI and EMG. All subjects took the same conservative treatments for 4 weeks and then, they were re-evaluated by PDI, VAS and PRS. RESULTS: BDI score was positively correlated with VAS and PRS significantly. All groups were not different with respect to functional limitation (measured by PDI) and organic lesion (measured by MRI and EMG study). But, subjective pain (measured by VAS, PRS) were severe in depressed group. All groups showed improvement in PDI, VAS and PRS after 4 weeks of treatment. But, the amount of improvement was greater in non-depressed group. CONCLUSION: The clinician treating chronic low back pain should be familiar with depression and prepare for screening on that.

Purification and characterization of a 33 kDa serine protease from Acanthamoeba lugdunensis KA/E2 isolated from a Korean keratitis patient

In order to evaluate the possible roles of secretory proteases in the pathogenesis of amoebic keratitis, we purified and characterized a serine protease secreted by Acanthamoeba lugdunensis KA/E2, isolated from a Korean keratitis patient. The ammonium sulfate-precipitated culture supernatant of the isolate was purified by sequential chromatography on CM-Sepharose, Sephacryl S-200, and mono Q-anion exchange column. The purified 33 kDa protease had a pH optimum of 8.5 and a temperature optimum of 55 degrees C. Phenylmethylsulfonylfluoride and 4- (2- Aminoethyl) -benzenesulfonyl-fluoride, both serine protease specific inhibitors, inhibited almost completely the activity of the 33 kDa protease whereas other classes of inhibitors did not affect its activity. The 33 kDa enzyme degraded various extracellular matrix proteins and serum proteins. Our results strongly suggest that the 33 kDa serine protease secreted from this keratopathogenic Acanthamoeba play important roles in the pathogenesis of amoebic keratitis, such as in corneal tissue invasion, immune evasion and nutrient uptake.

Behavioral and Emotional Problems for the Patient with Duchenne Muscular Dystrophy

OBJECTIVE: To identify psychological disturbance occurring in Duchenne Muscular Dystrophy (DMD) children. METHOD: Fifty one DMD children aged from 5 up to 14 years and 51 age matched healthy children were evaluated. Korean child behavioral cheak list (K-CBCL) was used to evaluate psychological problems in DMD and healthy control children. Korean Wechsler Intelligence Scale for children were performed in DMD children to evaluate cognitive function. To evaluate children's functional level, Brooke's scale for upper extremities and Vignos' scale for lower extremities were used. A correlational analysis was performed between age and total IQ score and K-CBCL subscales. RESULTS: K-CBCL profiles of the DMD children and control group revealed that DMD children obtained significantly lower scores on social, school, total social competence scales (P<0.01) and significantly higher scores on withdrawn, somatic complaints, anxious/depressed, immaturity, attention problems, internalizing problem, total behavior problems and emotional ability (P<0.01). Correlations of the age and functional level of the DMD group with each social scale of the CBCL resulted in significant negative relationship on social, school, and total social competence scales (P<0.01) and significant positive relationship on withdrawn, somatic complaints, anxious/depressed, immaturity, internalizing problems and total behavior problems (P<0.01). Correlational analysis of IQ score of the DMD group and each scale of the CBCL revealed no significant relationships except school (P<0.05) and total behavioral problem (P<0.05). CONCLUSION: We concluded that DMD children suffer from wide spectrum of psychological disturbance such as somatic complaints, attention and emotional problems in addition to expected psychological problems due to chronic disease and its progression. Thus, for the successful rehabilitation, these various emotional disturbances need proper treatment.

Intellectual impairement in patients with muscular dystrophy

No abstract available.