ABSTRACT
Abstract Phenylketonuria (PKU) is caused by deficient activity of phenylalanine hydroxylase (PAH), responsible for the conversion of phenylalanine (Phe) to tyrosine (Tyr). Monitoring of patients with PKU requires the measurement of Phe in plasma using high-performance liquid chromatography (HPLC) or in dried blood spots (DBS) using different techniques to adjust treatment strategy. The objective of this study was to evaluate Phe levels in DBS measured by two different methods and compare them with Phe levels measured in plasma by HPLC. We analyzed 89 blood samples from 47 PKU patients by two different methods: fluorometric method developed in-house (method A) and the commercially available PerkinElmer® Neonatal Phenylalanine Kit (method B) and in plasma by HPLC. The mean Phe levels by method A, method B, and HPLC were 430.4±39.9μmol/L, 439.3±35.4μmol/L, and 442.2±41.6μmol/L, respectively. The correlation values between HPLC and methods A and B were 0.990 and 0.974, respectively (p < 0.001 for both). Our data suggest that methods A and B are useful alternatives for monitoring Phe levels in patients with PKU, with method A being in closer agreement with the reference standard (HPLC).
ABSTRACT
A total of 187 isolates from 470 clinical specimens were collected from three hospitals in El-Minia governorate and identified as 132 Staphylococcus aureus strains and 55 coagulase-negative staphylococci (CoNS) strains. Susceptibility of isolates to antimicrobial agents was tested by the agar dilution method. The isolated S. aureus strains showed low resistance to vancomycin (1.5 percent), amikacin (2.3 percent) and gatifloxacin (3.8 percent). Vancomycin was the most effective antibiotic against CoNS. The ampicillin-resistant isolates were tested for â-lactamase production where, 61.7 percent of S. aureus and 42.9 percent of CoNS were positive for â-lactamase enzyme. Beta-lactamase producing strains were screened for their plasmid profile using alkaline lysis method. Some of these strains carried at least one plasmid suggesting plasmid-mediated antibiotic resistance. When cells of these strains were exposed to curing agent ethidium bromide, the production of the â-lactamase was lost. Resistance by efflux was studied by a modified fluorometric assay. Addition of uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP) increased norfloxacin accumulation in quinolone resistant S. aureus strains, suggesting endogenous energy-dependent efflux. Combinations of ciprofloxacin with four antimicrobial agents against methicillin resistant S.aureus (MRSA) strains were investigated using decimal assay for additivity (DAA) technique. Synergistic interaction was observed between ciprofloxacin and oxacillin. ciprofloxacin plus cefepime and gentamicin appeared to be additive, while ciprofloxacin plus erythromycin was antagonistic.
Subject(s)
Humans , Coagulase , Disease Susceptibility , Drug Resistance, Microbial , Staphylococcal Infections , Staphylococcus aureus/enzymology , Staphylococcus aureus/isolation & purification , beta-Galactosidase/isolation & purification , Diagnostic Techniques and Procedures , Enzyme Activation , Fluorometry , MethodsABSTRACT
On the fluorescent reaction of ethidium bromide binding double-stranded DNA after cell ly-sis has been used to develop a rapid fluorometric assay for cytotoxicity. By using this technique,the cytotoxic activity of effector cells against target cells can be assayed by measuring the fluo-rescent intensities of the residual target cell DNA and the control target cell DNA. Our experi-mental results show that the fluorescent intensity of the uninjured, residual K562 cell DNA is ininverse relation to the cytotoxic activity of NK cells after incubation of peripheral bloed lympho-cytes with K562 cells. for 20 hr, at a different ratio of effector cell to target cell. We detected thecytotoxic activities of NK cells of perpheral blood lymphocytes from 34 normal individuals and 30cancer patients, and their mean percentages of NK cytotoxicity were 51.96?6.62% and 25.02?10.83% respectively, and had much significant deviation statistically(P