Comparative Analysis of the Efficacies of the GeneXpert and Solid Culture Media Techniques in the Diagnosis of Mycobacterium Tuberculosis

Tuberculosis is one of the predominant infectious diseases causing significant deaths worldwide. Detection of Mycobacterium tuberculosis bacilli (MTB) using culture media was officially recognized by World Health Organization. However, there is a significant limitation in the authenticity of evaluation for its effectiveness on clinically important attributes. GeneXpert detects the presence of Mycobacterium tuberculosis (M. tuberculosis) based on the detection of nucleic acid and is able to identify the resistance of both isoniazid (INH) and Rifampicin (RIF) drugs. In this technique, DNA amplification is done using the GeneXpert instrument in the suspected sample with a specific reagent cartridge. Although GeneXpert is a rapid technique compared to other diagnostic tools for MTB identification due to false-negative results, the culture media technique is still considered the gold standard in detecting M. tuberculosis. The current study was designed to evaluate the comparative efficacies of GeneXpert and the solid culture media technique in identifying MTB. Sputum samples of 250 (n=250) suspected tuberculosis (TB) patients were investigated using both diagnostic techniques. The results revealed that out of the 250 suspected patients, 30 (12%) samples were positive with the culture media technique, while only 17 (6.8%) samples showed positive results with GeneXpert. Culture tests and GeneXpert are not equally efficient in detecting M. tuberculosis. The current study's findings showed that the culture-based detection method for M. tuberculosis is more efficient and reliable than GeneXpert.

Helicobacter pylori: correlation of the virulence marker iceA allele with clinical outcome in a high prevalence area

The association of Helicobacter pylori virulence marker 'induced by contact with epithelium A' (iceA) allele types was determined in H. pylori-related diseases and virulence markers. Gastric biopsies were obtained at EGD from patients for culture, histopathology and polymerase chain reaction (PCR) for iceA types, cagA and vacA alleles. Two hundred and eighty-four H. pylori isolates were examined. iceA type 1 was positive in 177 (62%) and iceA type 2 in 158 (56%). In iceA type 2, gastric ulcer was present in 34 (21%) (P < 0.001) and carcinoma in 28 (25%) (P = 0.002), compared to nine (8%) and 2 (2%) in iceA type 2-negative cases. For iceA type 2, 139 (88%) were associated with chronic active gastritis compared to 95 (75%) (P = 0.006) in iceA type 2-negative. H. pylori cagA was positive in 101 (64%) iceA type 2 strains compared to 57 (45%) in negative strains (P = 0.002). H. pylori iceA type 2 was dominant and associated with cagA, chronic active inflammation, gastric ulcer and carcinoma.

Immunocytochemical characterization of neuroendocrine tumours of the larynx

Twenty-two neuroendocrine tumours of the larynx were investigated using a panel of immunocytochemical markers. Three were small cell carcinomas, eight were large cell neuroendocrine carcinomas and 11 were paragangliomas. Twenty were positive for protein gene product 9.5, 19 for neuron-specific enolase, 15 for chromogranin A, nine for bombesin, eight for substance P, eight for neuropeptide Y, eight for metenkephalin, seven for somatostatin, five for calcitonin, eight for calcitonin gene-related peptide and one for vasoactive intestinal polypeptide. Bombesin immunoreactivity was largely restricted to the small cell carcinomas and large cell neuroendocrine carcinomas and neuropeptide Y, metenkephalin and substance P to the paragangliomas. This comprehensive immunocytochemical analysis of neuroendocrine tumours of the larynx demonstrates that these tumours represent special entities but have similar patterns of immunostaining to those of neuroendocrine tumours in other sites.

Porphyrin metabolism in some malignant diseases

Porphyrin metabolism was studied in 21 children of both sexes suffering from acute lymphoblastic leukaemia (ALL) and 34 adult patients of different ages and sexes suffering from ALL (n = 14), non-Hodgkin's lymphoma (NHL), n = 14, or Hodgkin's disease (HD), n = 6. In addition, two groups of healthy children (n = 14), and adults (n = 17) were studied for comparison. It was apparent from this study that the activity of uroporphyrinogen-1-synthetase (URO-1-S, E.C. 4.3.1.8) was highly significantly activated in the blood of children, while the activities of blood 5-aminolevulinic acid dehydrase (E.C. 4.2.1.24) and ferrochelatase (E.C. 4.99.1.1.), as expressed by protoporphyrin/haem ratio, were inhibited in those children. Also, free erythrocyte total porphyrins were increased, while the haem content was reduced. The concentrations of 5-aminolevulinic acid, coproporphyprin and uroporphyrin were increased in the urine of children with ALL. On the other hand, some dramatic changes were found in porphyrin metabolism in adult patients suffering from ALL, NHL and HD. The aforementioned disturbances were discussed in the light of some factors which may affect the enzymatic activities in the synthesis of porphyrins.

[Nifedipine (a calcium antagonist) in the treatment of urinary obstruction (author's transl)]

Nifedipine (10 mg orally) had a relaxing effect on the ureters of 25 patients with various forms of urinary obstruction. At a daily dose of 30 mg this effect can be used for treating neurogenic disorders of bladder emptying due to unrestrained detrusor contractions.