Investigation of saliva, faeces, urine or semen samples for the presence of GBV-C RNA

GBV-C/HGV has been demonstrated to be distributed worldwide with a prevalence in blood donors higher than HCV. This distribution in the general population probably requires an effective non-parenteral route of transmission. A previous study was performed to evaluate the presence of GBV-C/HGV in serum. Saliva, faeces and urine samples of 30 patients (15 males and 15 females) and 15 semen samples from patients whose serum gave a GBV-C/HGV RNA positive result were then tested by a sensitive polymerase chain reaction (PCR) test. Five semen supernatant samples (33.3%) tested positive--four of them belonged to HIV positive patients--and two saliva samples contained GBV-C/HGV sequences (6.6%)--one from a HIV-positive patient. An internal control was used to detect PCR nonspecific inhibitors in the samples. The data suggest possible non-parenteral routes of transmission from this virus. Its presence in body fluids other than serum has clinical implications other than possible hepatic damage that remain to be investigated.

Coamplification of 3-hydroxy-3-methylglutaryl coenzyme A reductase genes in methotrexate-resistant human leukemia cell lines

Methotrexate (MTX)-resistant K562 human myelocytic leukemia sublines with 20- and 200-fold amplified dihydrofolate reductase (DHFR) genes localized to homogeneously staining regions (HSRs) on the long arms of chromosomes 5, 6, and 19 were used to examine whether other genes mapping close to the DHFR genes were coamplified. The gene for 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, located on chromosome 5q13.3-14, was coamplified 4-14-fold, corresponding to the levels of resistance exhibited by these cells. Similar observations were made with a MTX-resistant subline of the promyelocytic leukemia cell line, HL-60R, with 200 gene copies of DHFR. These observations indicate a tight linkage of DHFR and HMG-CoA genes on chromosome 5q.

Periodontal evaluation in patients undergoing maxillary expansion

Maxillary transverse diameter expansion is a treatment various authors have claimed is related to the development of gingival recession on the teeth of the upper arch. The aim of the present study was to compare such an incidence in two different groups of patients: those treated with surgically assisted rapid maxillary expansion and orthopedic expansion, respectively. Both treatments achieved the goal of expanding the transverse dimension (5.3 and 4.4 mm, respectively), but a significant difference was shown by the chi 2 test for the incidence of gingival recession of premolar/molar upper teeth, more than double for the latter than for the former. Therefore, surgically assisted rapid maxillary expansion seems to be an orthodontically effective procedure, safer than the orthopedic treatment regarding the possible development of mucogingival problems.

Methotrexate resistant cells as targets for selective chemotherapy

Strategies that are selective for eradicating methotrexate resistant cells are described. These strategies have been developed based on knowledge of the mechanism of drug resistance encountered in experimental systems and in the clinic. Drug resistance to methotrexate in experimental tumors is commonly due to either gene amplification (dihydrofolate reductase) or to impaired transport of methotrexate. While no effective drugs or methods to prevent gene amplification have been described, the concept of developing "pro drugs", i.e. a drug that is selectively reduced by dihydrofolate reductase to an inhibitor of another critical folate enzyme (thymidylate synthase, methionine synthetase, folylpolyglutamate synthetase) remains worthwhile. Second generation antifolates such as trimetrexate which are effective vs methotrexate transport resistant cells have already been developed and are in clinical trial.