The role of nitric oxide in cancer

Nitric oxide (NO) is a pleiotropic regulator, critical to numerous biological processes, including va-sodilatation, neurotransmission and macrophage-mediated immunity. The family of nitric oxide synthases(NOS) comprises inducible NOS (iNOS), endothelial NOS (eNOS), and neuronal NOS (nNOS). Interest-ingly, various studies have shown that all three isoforms can be involved in promoting or inhibiting theetiology of cancer. NOS activity has been detected in tumour cells of various histogenetic origins and hasbeen associated with tumour grade, proliferation rate and expression of important signaling componentsassociated with cancer development such as the oestrogen receptor. It appears that high levels of NOSexpression (for example, generated by activated macrophages) may be cytostatic or cytotoxic for tumorcells, whereas low level activity can have the opposite effect and promote tumour growth. Paradoxicallytherefore, NO (and related reactive nitrogen species) may have both genotoxic and angiogenic properties.Increased NO-generation in a cell may select mutant p53 cells and contribute to tumour angiogenesis byupregulating VEGF. In addition, NO may modulate tumour DNA repair mechanisms by upregulating p53,poly(ADP-ribose) polymerase (PARP) and the DNA-dependent protein kinase (DNA-PK). An understand-ing at the molecular level of the role of NO in cancer will have profound therapeutic implications for thediagnosis and treatment of disease.     

Studies on photosynthesis in the ear of wheat

Estimates of varietal differences in photosynthesis by ears of wheat, obtained by shading ears or stems, are compared with estimates obtained from a technique involving removal of spikelets at anthesis. The results obtained by different techniques and in different seasons differed widely.     

First Description of Various Bacteria Resistant to Heavy Metals and Antibiotics Isolated from Polluted Sites in Tunisia

Environmental bacteria belonging to various families were isolated from polluted water collected from ten different sites in Tunisia. Sites were chosen near industrial and urban areas known for their high degree of pollution. The aim of this study was to investigate cross-resistance between heavy metals (HM), i.e., silver, mercury and copper (Ag, Hg, and Cu), and antibiotics. In an initial screening, 80 isolates were selected on ampicillin, and 39 isolates, retained for further analysis, could grow on a Tris-buffered mineral medium with gluconate as carbon source. Isolates were identified based on their 16S rRNA gene sequence. Results showed the prevalence of antibiotic resistance genes, especially all isolates harbored the bla_TEM gene. Some of them (15.38%) harbored bla_SHV. Moreover, several were even ESBLs and MBLs-producers, which can threaten the human health. On the other hand, 92.30%, 56.41%, and 51.28% of the isolates harbored the heavy metals resistance genes silE, cusA, and merA, respectively. These genes confer resistance to silver, copper, and mercury. A cross-resistance between antibiotics and heavy metals was detected in 97.43% of our isolates.     

Cytological aspects of uterine cervical adenocarcinoma, adenosquamous carcinoma and combined adenocarcinoma-squamous carcinoma: appraisal of diagnostic criteria for in situ versus invasive lesions

Cytological aspects of uterine cervical adenocarcinoma, adenosquamous carcinoma and combined adenocarcinoma-squamous carcinoma: appraisal of diagnostic criteria for in situ versus invasive lesions
This paper reports the cytological findings based on air-dried smears in a retrospective series of 143 cases of endocervical adenocarcinoma, combined adenocarcinoma-squamous carcinoma and adenosquamous carcinoma drawn from the files of the BC Cancer Registry. Cervical cytology smears were available before biopsy in 131 patients, but in 18 cases the cytology showed no abnormality. Malignant changes or high-grade atypia of glandular and/or squamous cells (defined as moderate or severe dyskaryosis) were detected in 103 cases. In 46 cases, only a high-grade squamous abnormality was detected. Low-grade glandular and/or squamous lesions were detected in nine cases and one showed atypical endometrial-type glands. The cervical smears of 64 cases were reviewed in detail to determine the important cytomorphological criteria of in situ and invasive adenocarcinoma in air-dried smears, the technique used for preparing PAP smears in British Columbia. Endocervical cells were absent in four cases. Numerous (>10) groups of glandular cells were present in 51 cases. Important clues to the diagnosis of adenocarcinoma included crowding of nuclei, stratification of nuclei, loss of polarity, syncytial balls and papillary groups of glandular cells, nuclear enlargement, nuclear pleomorphism, and the presence of free-lying atypical glandular cells. Nuclear hyperchromatism, chromatin pattern, nuclear borders, nuclear membranes, and numbers and morphology of nucleoli were not helpful criteria in our material. Criteria enabling reliable distinction between in situ and invasive adenocarcinoma and/or mixed adenocarcinoma-squamous carcinoma could not be established.     

Isolation of purified copper protein from horse liver

1. A procedure is described for isolating a copper protein from horse liver in pure form, in a state that appears to be crystalline. 2. This copper protein is colored blue-green, and its copper content varied between 0.3 and 0.4 per cent. No indication of any catalytic properties was obtained in the limited number of tests made. Because of its variable copper content, the protein may function for the storage of copper in the body. 3. The copper could be removed partly from the protein by dialysis against cyanide, and a colorless crystalline protein was obtained by lowering the pH to 5.0, followed by dialysis. The original blue-green color of the protein could be restored by dialysis against copper acetate solution.     

In Vitro Propagation of the Protozoan Perkinsus Marinus, A Pathogen of the Eastern Oyster, Crassostrea Virginica

ABSTRACT. Perkinsus marinus , a pathogen of eastern oysters ( Crassostrea virginica ), has been successfully propagated in vitro. Cultures of the parasite were initiated from heart fragments of an infected oyster. the cultured protozoan (designated Parkinsus -1) was similar in morphology at both the light and transmission electron microscopy levels to histozoic stages of P. marinus in naturally infected oysters. In addition, cultured cells incubated in fluid thioglycollate medium produced enlarged cells (prezoosporangia) that stained blue-black in Lugol's solution, a response characteristic to Perkinsus spp. and used in routine diagnosis. Polyclonal antibodies raised against P. marinus prezoosporangia reacted positively to Perkinsus -1. Finally, the cultured cells infected susceptible oysters and reisolation of Perkinsus -1 cells was possible from the hearts of experimentally infected oysters. the culture medium contained most of the known constituents of cell-free hemolymph of oysters. the success achieved in culturing P. marinus will allow further investigations aimed at reducing mortalities caused by this important oyster pathogen and at addressing many unanswered questions about its biology and pathobiology.     

Comparative Studies of Net Photosynthesis and Transpiration of Some Citrus Species and Relatives

Comparisqns were made between ‘Campbell Valencia’ orange (Citrus sinensis (L.) Osbeck), and ‘Gabon Cherry-orange’ (Citropsis gabunensis (Engl.) Swing.), ‘Frost Lisbon’ lemon (Citrus limon (L.) Burm. f.) and ‘Eremolemon’ (Eremocitrus glauca (Lindl.) Swing. ×Citrus limon (L.) Burm. f.) and between diploid and autotetraploid ‘Lisbon’ lemons with respect to the influences of temperature and humidity on net photosynthesis and transpiration. Net photosynthesis, leaf conductance to water vapor and water-use-efficiency of Citropsis gabunensis were lower than with Citrus sinensis.‘Eremolemon’ had higher net photosynthesis and higher water-use-efficiency than ‘Lisbon’ lemon, but only small differences were observed between the two species in leaf conductance to water vapor. Small, nonsignificant, differences were observed between diploid and tetraploid ‘Lisbon’ lemons in responses of net photosynthesis and leaf conductance to temperature and humidity. Temperatures above 30°C and increases in vapor pressure difference caused declines in net photosynthesis and increases in vapor pressure difference resulted in decreases in leaf conductance to water vapor by all of the species used in these studies.