Mutation spectrum and birth prevalence of inborn errors of metabolism among Emiratis. A study from Tawam hospital metabolic center, United Arab Emirates

This study aimed to determine the mutation spectrum and prevalence of inborn errors of metabolism [IEM] among Emiratis. The reported mutation spectrum included all patients who were diagnosed with IEM [excluding those with lysosomal storage diseases [LSD]] at Tawam Hospital Metabolic Center in Abu Dhabi, United Arab Emirates, between January 1995 and May 2013. Disease prevalence [per 100,000 live births] was estimated from data available for 1995-2011. In 189 patients, 57 distinct IEM were diagnosed, of which 20 [35%] entities were previously reported LSD [65 patients with 39 mutations], with a birth prevalence of 26.87/100,000. This study investigated the remaining 37 [65%] patients with other IEM [124 patients with 62 mutations]. Mutation analysis was performed on 108 [87%] of the 124 patients. Five patients with biotinidase deficiency had compound heterozygous mutations, and two siblings with lysinuric protein intolerance had two homozygous mutations. The remaining 103 [95%] patients had homozygous mutations. As of this study, 29 [47%] of the mutations have been reported only in Emiratis. Two mutations were found in three tribes [biotinidase deficiency [BTD, c.1330G>C] and phenylketonuria [PAH, c.168+5G>C]]. Two mutations were found in two tribes [isovaleric aciduria [IVD, c.1184G>A] and propionic aciduria [PCCB, c.990dupT]]. The remaining 58 [94%] mutations were each found in individual tribes. The prevalence was 48.37/100,000. The most prevalent diseases [2.2-4.9/100,000] were biotinidase deficiency; tyrosinemia type 1; phenylketonuria; propionic aciduria; glutaric aciduria type 1; glycogen storage disease type Ia, and mitochondrial deoxyribonucleic acid depletion. The IEM birth prevalence [LSD and non-LSD] was 75.24/100,000. These results justify implementing prevention programmes that incorporate genetic counselling and screening

cytotoxicity of aflatoxin B[1] in human lymphocytes

Aflatoxin B[1] [AFB[1]] is a naturally occurring carcinogenic and immunosuppressive compound. This study was designed to measure its toxic effects on human peripheral blood mononuclear cells [PBMC]. The study recruited 7 healthy volunteers. PBMC were isolated and cellular respiration was monitored using a phosphorescence oxygen analyser. The intracellular caspase activity was measured by the caspase-3 substrate N-acetyl-asp-glu-val-asp-7-amino-4-methylcoumarin. Phosphatidylserine exposure and membrane permeability to propidium iodide [PI] were measured by flow cytometry. Cellular oxygen consumption was inhibited by 2.5 micro M and 25 micro M of AFB[1]. Intracellular caspase activity was noted after two hours of incubation with 100 micro M of AFB[1]. The number of Annexin V-positive cells increased as a function of AFB[1] concentration and incubation time. At 50 micro M, a significant number of cells became necrotic after 24 hours [Annexin V-positive and PI-positive]. The results show AFB[1] is toxic to human lymphocytes and that its cytotoxicity is mediated by apoptosis and necrosis

Mitochondrial oxygen consumption by the foreskin and its fibroblast-rich culture

This study investigated the feasibility of using a phosphorescence oxygen analyser to measure cellular respiration [mitochondrial O[2] consumption] in foreskin samples and their fibroblast-rich cultures. Foreskin specimens from normal infants were collected immediately after circumcision and processed for measuring cellular respiration and for culture. Cellular mitochondrial O[2] consumption was determined as a function of time from the phosphorescence decay of the Pd [II] meso-tetra-[4-sulfonatophenyl]-tetrabenzoporphyrin. In sealed vials containing a foreskin specimen and glucose, O[2] concentration decreased linearly with time, confirming the zero-order kinetics of O[2] consumption by cytochrome oxidase. Cyanide inhibited O[2] consumption, confirming that the oxidation occurred mainly in the mitochondrial respiratory chain. The rate of foreskin respiration [mean +/- SD] was 0.074 +/- 0.02 microM O[2] min[-1] mg[-1] [n = 23]. The corresponding rate for fibroblast-rich cultures was 9.84 +/- 2.43 microM O[2] min[-1] per 10[7] cells [n = 15]. Fibroblast respiration was significantly lower in a male infant with dihydrolipoamide dehydrogenase gene mutations, but normalised with the addition of thiamine or carnitine. The foreskin and its fibroblast-rich culture are suitable for assessment of cellular respiration. However, the clinical utility of foreskin specimens to detect disorders of impaired cellular bioenergetics requires further investigation

Caffeine impairs HL-60 cellular respiration

We investigated the effect of caffeine on mitochondrial O[2] consumption in human promyelocytic leukemia [HL-60] cells. A phosphorescence analyzer that measures O[2] concentrations in cell suspensions as function of time was used for this purpose. O[2] concentrations were determined from the phosphorescence of Pd phosphor, calculated by fitting the phosphorescence decays to exponentials. In sealed vials, O[2] concentrations in the cell suspensions containing glucose declined linearly with time, showing zero-order kinetics for O[2] consumption. NaCN inhibited O[2] consumption, confirming the oxidation occurred in the mitochondrial respiratory chain. A rapid decline in the rate of respiration was observed when 50 [micro]M to 4.0 mM caffeine was added to HL-60 cells in cell growth media [containing 1.41 mM Ca[2+]] or phosphate-buffered-salts [containing 0.91 mM Ca[2+]]. This reversible inhibition was blocked by verapamil and was concentration-dependent, reaching a plateau [43 +/- 7% inhibition] at 50 [micro]M caffeine. The inhibition was not observed when cellular Can+ stores were depleted. T-cell lymphoma [Jurkat] cells and isolated mitochondria were less sensitive to caffeine. Thus, caffeine is a potent inhibitor of HL-60 respiration. This effect is possibly mediated by Ca[2+]-flooding into the cytosol and neighboring mitochondria

Gossypol inhibits proliferation of endometrioma cells in culture / 亚洲男科学杂志(英文版)

<p><b>AIM</b>To evaluate the anti-proliferative activity and mitochondrial toxicity of gossypol in endometrioma cells maintained in short-term cultures.</p><p><b>METHODS</b>(A) Three endometrioma cell lines from patients were treated with 25 or 50 nmol/L gossypol for up to 12 days. The effect of gossypol on the cell growth was recorded. (B) A phosphorescence oxygen analyzer was used to determine the effects of gossypol on mitochondrial oxygen consumption of six endometrioma cell lines from patients. (C) Cellular gossypol accumulations in three endometrioma cell lines from patients were measured by high-pressure liquid chromatography.</p><p><b>RESULTS</b>Proliferation of the endometrioma cells was inhibited by 25 and 50 nmol/L gossypol. Respiration of the endometrioma cells was inhibited by 10 micromol/L gossypol. Cellular gossypol was detected in the endometrioma cell lines that were treated for 24 h with 10 and 0.3 micromol/L gossypol.</p><p><b>CONCLUSION</b>Gossypol invokes a potent toxicity on cultured endometrioma cells.</p>