A comparison of hepatitis A and hepatitis B measures among vaccinated and susceptible online men who have sex with men.

Hepatitis A virus (HAV) and hepatitis B virus (HBV) continue to be major health concerns among men who have sex with men (MSM). The Internet both facilitates high-risk sexual encounters and provides opportunities for promoting healthy behaviours. This study compared self-reported HAV and HBV vaccination levels, based on demographics, health characteristics, hepatitis knowledge, attitudes and risk behaviours among MSM using an online survey posted from February through June 2005. Each participant (n = 968) reported whether they were vaccinated, infected or susceptible for hepatitis A and/or for hepatitis B. Men whose health-care provider recommended vaccination were 12.91 (95% confidence interval [CI] 8.11, 20.55) times more likely to be vaccinated against HAV and 17.93 (95% CI 10.82, 29.70) times more likely to be vaccinated against HBV than those at risk of infection, respectively. These data provide essential information for public health professionals to successfully promote vaccination among members of this population.

Fat digestion in the newborn. Characterization of lipase in gastric aspirates of premature and term infants.

We have measured lipolytic activity in gastric aspirates obtained at birth in a group of 142 infants. The infants ranged in gestational age from 26 to 41 wk. Lipolytic activity, measured by the hydrolysis of long chain triglyceride ([tri-(3)H]oleate), and expressed as nanomoles FFA per milliliter gastric aspirate per minute was 333+/-66 in 55 small premature infants (gestational age 26-34 wk and body wt 750-2,000 g) and 558+/-45 in a group of 87 larger infants (gestational age 35-41 wk and body wt 2,020-4,000 g). No activity was detected in seven infants with an unusually low pH in the gastric aspirate, 2.88+/-0.44 (compared with a mean pH level of 5.59+/-0.22 in the other 135 infants). Attempts to characterize this lipase showed that it has a molecular weight of 44-48,000, pH optimum of 3.0-5.0, that FFA acceptors (albumin) stimulate activity, whereas bile salts, taurocholate and glycocholate, cause marked inhibition at concentration >3 mM. Our survey shows that enzyme activity is present as early as 26 wk of gestation, increases with gestational age, and has the same characteristics throughout gestation. The data show that the lipase in gastric aspirates differs from pancreatic lipase, but closely resembles human and rat lingual lipase. Because the lipase has a low pH optimum and does not require bile salts, it can act in the stomach where it initiates the hydrolysis of dietary fat. We suggest that intragastric lipolysis is probably of major importance in the newborn and especially in the premature infant where it compensates not only for low pancreatic lipase, but in addition, helps to overcome the temporary bile salt deficiency through the formation of amphiphilic reaction products.

Growth inhibition efficacy of an adenovirus expressing dual therapeutic genes, wild-type p53, and anti-erbB2 ribozyme, against human bladder cancer cells.

The altered expression of both p53 and erbB2 is strongly related to the disease status and the outcome of bladder cancers. We examined the antitumor efficacy by the modulation of these genetic alterations with a newly designed dual-gene-expressing adenovirus (Ad-p53/erbB2Rz), which expresses p53 and anti-erbB2 ribozyme simultaneously in human bladder cancer cells. Cell growth inhibition efficacy along with biological responses of this virus was compared with other viral vectors (Ad-p53, which expresses wild-type p53 cDNA, and Ad-erbB2Rz, which expresses anti-erbB2 ribozyme, solely or in combination). Sufficient transgene expression in targeted cells and the altered expression of the targeted genes and their encoded proteins were obtained by each therapeutic vector. Each of the three therapeutic viral vectors inhibited bladder cancer cell growth, and the putative additive antitumor effect was shown by the combination of two of the therapeutic vectors. Furthermore, Ad-p53/erbB2Rz had superior therapeutic efficacy when the same titers of viruses were infected. Nonspecific vector-related toxicity was minimized by reducing the total amount of viral titers by using the dual-gene-expressing adenovirus. Modulation of multiple genetic abnormalities might enhance the therapeutic efficacy, and vector-related toxicity could be minimized when the total amount of viral titers are reduced.

Schedule-dependent enhancement of the cytotoxicity of fluoropyrimidines to human carcinoma cells in the presence of folinic acid.

Previous studies from this laboratory indicated that the cytotoxic effects of the fluoropyrimidines on mouse leukemic cells are substantially augmented by folinic acid but that these effects are underestimated in growth inhibition experiments. These results have now been extended to two human tumor cell lines, the WiDr colorectal and T-24 bladder carcinoma cells. In both cell lines, the presence of folinic acid in the medium substantially enhanced the cytotoxicity of a 72-h exposure to either 5-fluorouracil (FUra) or 5-fluoro-2'-deoxyuridine. Folinic acid concentration-response curves for enhancement of the cytotoxicity of FUra to WiDr cells were broad but indicated that response was not maximal until at least 10 microM. Likewise, increased length of exposure to 10 microM folinic acid continuously enhanced the cytotoxicity of a 72-h treatment with FUra, but substantial enhancement was observed even after a 2-h exposure to folinate, and there was a diminished increment of cytotoxicity after 24-h exposure to folinic acid. Surprisingly, folinic acid augmentation of the cytotoxicity of a brief exposure to FUra (4 h) was minimal but enhancement of FUra cytotoxicity became much more pronounced with intervals of exposure to FUra of greater than or equal to 24 h. If these results can be mimicked in vivo without undue host toxicity, our experiments suggest that a substantial improvement in the therapeutic activity of FUra plus folinate would result from prolonged exposure to both agents.

Properties of amino acid transport systems in K562 cells sensitive and resistant to cis-diamminedichloroplatinum(II).

When K562 cells were made resistant to cisplatin their neutral amino acid transport systems changed. K562 cells cloned in cisplatin developed a 6.7-fold resistance to the drug. The generation times for K562 cells sensitive (S) and resistant (DDP) to cisplatin were similar. The initial uptake and rapid efflux of cisplatin were similar in both cell lines. However, they differed in their sodium dependent neutral amino acid transport properties. In K562S cells the sodium-dependent uptake for methylaminoisobutyric acid was significantly inhibited by threonine (Ki = 10.3 mM), but in K562DDP the uptake of neutral amino acids was significantly lower, and methylaminoisobutyric acid uptake was minimally inhibited by threonine. When K562DDP cells were grown in the absence of cisplatin for 8 weeks, their amino acid transport properties reverted to those of K562S cells. In K562 cells, changes in plasma membrane essential amino acid transport systems were concomitant to both the development of resistance and the redevelopment of sensitivity to cisplatin. Therefore, human malignant cell sensitivity and resistance to cisplatin may be related to membrane nutrient transport systems.

Heat radiosensitization and the level of DNA polymerases alpha and beta of human colony-forming unit-granulocyte-macrophage and myeloid leukemias sensitive and resistant to chemotherapeutic agents.

In these studies, heat radiosensitization in normal human colony-forming unit-granulocyte-macrophage (CFU-GM) and several different leukemic cell lines sensitive or resistant to chemotherapeutic agents were measured. Extent of heat radiosensitization was then correlated with the level of DNA polymerases alpha and beta in control and heat-shocked cells in order to examine whether there is a positive correlation between the degree of heat radiosensitization and the level of these enzymes. Our results show that human bone marrow CFU-GM have an x-ray response with D0 of 1.56 Gy and a small amount of heat radiosensitization with a thermal enhancement ratio (TER) of 1.2. K562, a human erythroleukemic cell, showed a D0 of 1.32 +/- 0.2 Gy and TER of 1.4. However, in contrast to normal CFU-GM which showed no shoulder in the X-ray survival curve, K562 cells showed a small shoulder with a quasi-threshold dose, (Dq) of 2 Gy and n of 2. K562 cells resistant to chemotherapeutic drugs such as 1-beta-D-arabinofuranosylcytosine and etoposide (VP-16) showed D0 of 1.47 +/- 0.13, and 1.77 +/- 0.18 Gy; Dq of 4 and 0 Gy; and n of 5 and 1; and TER of 1.6 and 2, respectively. The level of DNA polymerases alpha and beta activity and their respective mRNA levels were approximately the same in all cells. The reduction in the level of DNA polymerase beta after heat treatment however, correlated with the TER obtained for various leukemic cells. These studies indicate that normal CFU-GM and variety of human leukemic cells show only a small amount of heat radiosensitization. However, drug-resistant leukemic cells show a higher amount of heat radiosensitization than their drug-sensitive parent line. This suggests that hyperthermia may be beneficial in eradicating drug-resistant leukemic cells when combined with X-ray. Furthermore, the inactivation of DNA polymerase beta activity results in a higher amount of heat radiosensitization.

Neoplastic reversion accomplished by high efficiency adenoviral-mediated delivery of an anti-ras ribozyme.

Strategies have been developed to abrogate the aberrant expression of dominant oncogenes as a means to accomplish targeted tumor eradication. We have demonstrated previously the utility of this approach using a hammerhead ribozyme designed to cleave the mutant sequence in codon 12 of the activated H-ras oncogene transcript. To develop this strategy into a practical means to approach malignant disease, methods must be developed to accomplish high efficiency delivery of the ribozyme to target neoplastic cells. To accomplish this, a recombinant adenovirus was designed that encoded a gene cassette for the H-ras ribozyme. By using this virus, it was possible to accomplish high efficiency reversion of the neoplastic phenotype in mutant H-ras expressing tumor cells without the need for any selection steps. The demonstration of the utility of adenoviral-mediated delivery of anticancer ribozymes will allow the practical development of gene therapy strategies on this basis.

Inhibition of amino acid transport by cis-diamminedichloroplatinum(II) derivatives in L1210 murine leukemia cells.

The uptake of cis-diamminedichloroplatinum(II) (cisplatin) has been studied in the L1210 murine lymphoid leukemia cell line. Labeled cisplatin and its aquated derivatives were resolved by high-performance liquid chromatography on a strong cationic exchange column. After 10 min of incubation of cisplatin with the cells, the major portion of the non-protein-bound platinum was in the form of cisplatin. However, a portion of this platinum was converted with time to a derivative which coeluted with the monoaquo derivative of cisplatin. With the appearance of this derivative, there was a concomitant inhibition of sodium-dependent amino acid transport as measured by the uptake of aminoisobutyric acid and methionine. Furthermore, the exposure of L1210 cells to a preparation of predominantly aquated product(s) of cisplatin inhibited amino acid uptake following a brief (2-min) incubation, whereas measurable inhibition of amino acid uptake by cisplatin required a longer preincubation period. This inhibition of aminoisobutyric acid and methionine was dependent on the concentration of platinum. Aminoisobutyric acid and methionine were shown to be concentrated in L1210 cells in the presence of sodium ions, and competition experiments suggest similar uptake systems. Since L1210 cells are methionine-auxotrophic leukemic cells, inhibition of essential amino acid transport by cisplatin may be a mechanism of cytotoxic action.

Establishment of methotrexate-resistant human acute lymphoblastic leukemia cells in culture and effects of folate antagonists.

A human acute lymphoblastic T-cell line, MOLT-3, was fed with Roswell Park Memorial Institute Medium 1640-10% fetal bovine serum-antibiotics, containing increasing concentrations of methotrexate (MTX). After 10 months of feeding, the cells became resistant to 10(-7) M MTX; resistance was not reversed when the cells were placed in the original MTX-free medium. At 10(-7) M MTX, the concentration which produced complete inhibition of the parent MOLT-3 cell growth, the resistant cells were not inhibited at all. On a 50% inhibitory concentration basis, the resistant cells were approximately 30-fold more resistant to MTX. The parent MOLT-3 and the resistant line had the same doubling time of approximately 36 hr. There were no differences in light microscopic morphology. MOLT-3 produced loose colonies on 0.5% agar enriched with fetal bovine serum, whereas the colonies of the resistant line were tightly packed. The development of resistance was accompanied by a 4- to 5-fold decrease in [3H]MTX transport (MOLT-3/MTXt). Kinetic analysis of MTX uptake showed that the resistant subline did not have an altered Km for MTX (6.6 microM) but had a decreased Vmax of about 20% of the parent cell line. These data suggest that either the number of folate transport sites or the turnover rate of these sites has been reduced in the MTX-resistant cell line. Dihydrofolate reductase was only minimally elevated in the resistant cell line. The MTX-resistant cell line was cross-resistant to dichloromethotrexate. The sensitivity of the resistant line to the substituted 2,4-diaminoquinazoline and pyrimidine compounds, 2,4-diamino-5-methyl-6-[(3',4',5'-trimethoxyanilino) methyl] quinazoline (JB-11) and 2,4-diamino-5-(3',4'-dichlorophenyl)-6-methylpyrimidine, increased more than 3-fold. While leucovorin equally reversed the MTX effects on the parent and resistant cells, leucovorin reversal of 2,4-diamino-5-methyl-6-[(3',4',5'-trimethoxyanilino) methyl] quinazoline and 2,4-diamino-5-(3',4'-dichlorophenyl)-6-methylpyrimidine effects was limited only to the parent cell line. 2,4-diamino-5-methyl-6-[(3',4',5'-trimethoxyanilino) methyl] quinazoline or 2,4-diamino-5-(3',4'-dichlorophenyl)-6-methylpyrimidine plus leucovorin might prove to be unique in treating patients with acute lymphoblastic leukemia when the leukemic cells develop transport resistance to MTX.

Suppression of the neoplastic phenotype in vivo by an anti-ras ribozyme.

In this study, the efficacy of an anti-ras ribozyme in reversing the neoplastic phenotype was investigated. Murine NIH3T3 cells were transfected with cellular DNA from the FEMX-I human melanoma cell line expressing the activated H-ras gene. The transformed cells displayed the neoplastic phenotype in vitro and were tumorigenic in nude mice in vivo. When the transformants were transfected by a ribozyme designed to cleave only activated H-ras RNA, the transformed phenotype was abrogated. In contrast, expression of a mutant ribozyme, essentially acting only as antisense, into the transformed cells resulted in less dramatic changes in cell growth and tumorigenicity. These results reinforce the potential role of anti-oncogene ribozymes as suppressors of neoplastic growth, with possible implications for gene therapy.

Detection of drug resistance in human tumors by in vitro enzymatic amplification.

Both acquired and natural resistance to chemotherapy agents have proved problematic in the treatment of neoplasia. Thymidylate synthase, which catalyzes the synthesis of thymidine precursors, has been shown to be amplified in response to a variety of chemotherapeutic agents. The detection of such amplification could prove beneficial in the development of alternative clinical protocols. In this study we report the use of existing enzymatic amplification methods in order to detect incipient amplification of the thymidylate synthase gene upon resistance to cisplatin. The assay utilizes a modification of the polymerase chain reaction in which a sequence of the thymidylate synthase gene is amplified including two flanking oligonucleotides acting as primers for DNA synthesis. This method exhibits greater sensitivity than conventional nucleic acid detection methods and requires less than 100 ng of total RNA from patient tumors and no in vitro culturing of patient cells.

Characterization of a cisplatin-resistant human ovarian carcinoma cell line expressing cross-resistance to 5-fluorouracil but collateral sensitivity to methotrexate.

In vitro exposure of the TR170 ovarian carcinoma cell line to six intermittent 24-h treatments with a 90% inhibitory concentration of cisplatin (CDDP) (0.15 micrograms/ml; 0.5 microM) resulted in a 2-fold stably resistant subline designated TR170/CP+ (B.T. Hill et al., Int. J. Cancer, 39: 219-225, 1987). Resistance to CDDP in these CP+ cells has now been associated with reduced uptake of 195mCDDP (2-fold; P less than 0.01) and decreased removal of specific Pt-DNA adducts, quantitated immunochemically, indicative of an apparent increased tolerance of CDDP-induced DNA damage. Specifically these resistant cells appeared deficient in removal of the major cis-Pt-(NH3)2d(pGpG) adduct and the difunctional cis-Pt(NH3)2d(GMP)2 lesion, showed less efficiency in removing cis-Pt(NH3)2d(pApG) adducts, but proved as proficient as the parental cell line in removing DNA-DNA interstrand cross-links. Activities of DNA polymerase-alpha and -beta were comparable in both lines, and no significant alterations in glutathione metabolism were identified. Response to acute X-irradiation was not modified in these TR170/CP+ cells, but they showed marked (10-fold) cross-resistance to 5-fluorouracil and, unusually, proved collaterally sensitive (12-fold) to methotrexate. Resistance to 5-fluorouracil was associated with significantly increased thymidylate synthase activity (P less than 0.01), but this was not reflected in altered gene expression, while increased sensitivity to methotrexate was accompanied by increased drug uptake but by unaltered activity and expression of dihydrofolate reductase. These results indicate that exposure to CDDP can result in numerous alterations, both intracellularly and at the cellular membrane, reflected in significant changes in the tumor cells' responses to the cytotoxic effects of a range of antitumor drugs. The clinical relevance of these observations remains to be established.

Reversal of the in vivo metastatic phenotype of human tumor cells by an anti-CAPL (mts1) ribozyme.

The putative role of the CAPL gene in enhancing the development of human cancer metastasis was examined by transfecting human high-expressing osteosarcoma cells with a hammerhead ribozyme directed against the gene transcript. The ability of the ribozyme to cleave target mRNA in intact cells was demonstrated in a 5'-rapid amplification of cDNA ends assay. In transfected cells, a suppression of the capacity to give skeletal metastases upon intracardial injection into nude rats was observed in cell clones with reduced expression of CAPL mRNA and protein, whereas in vitro and in vivo cell proliferation and tumorigenicity were unchanged. The results provide direct evidence that the expression level of the CAPL-encoded protein can determine the metastatic potential of osteosarcoma cells, and they demonstrate an association between reduced gene expression and proliferation-independent inhibition of the metastatic capacity of human tumor cells. The effects of the specific cleavage of CAPL mRNA indicate that the gene product is involved in key cellular functions associated with the metastatic process and suggest that therapeutic modulation of the protein function may represent a novel approach for inhibiting the metastatic spread of cancer cells.

Evolution of methotrexate resistance of human acute lymphoblastic leukemia cells in vitro.

A human acute lymphoblastic T-cell line, MOLT-3, was fed with Roswell Park Memorial Institute Medium 1640 supplemented with 10% fetal bovine serum and antibiotics which contained increasing concentrations of methotrexate (MTX). The development of drug resistance was associated initially with progressive decrease in MTX transport. When the cells became 200-fold resistant, a rise in the dihydrofolate reductase was noted which was short-lived in the absence of the drug. A 10,000-fold increase in MTX resistance was accompanied, in addition to further decrease in MTX transport, by a 10-fold increase in the dihydrofolate reductase activity. While the purely transport-related resistant cell lines had a collateral sensitivity to lipid-soluble antifols, the sublines which had both transport- and enzyme-related MTX resistance contained a subpopulation highly resistant to these antifols. Chromosome analysis of the subline with increased dihydrofolate reductase activity showed an expanded abnormally banded region in chromosome 5.

Phase I trial of carboplatin and infusional cyclosporin in advanced malignancy.

PURPOSE: To determine the maximal-tolerated dose (MTD) of infusional cyclosporine (CSA) with fixed-dose carboplatin (CBDCA). PATIENTS AND METHODS: Clonogenic cytotoxicity assays were performed to assess the effect of CSA on reversal of resistance to CBDCA. The phase I study was performed in three phases. In phases 1 and 2, escalating-dose CSA (5, 7.5, 8.8, or 9.5 mg/kg/d) with fixed-dose CBDCA 300 or 250 mg/m2 were administered. Phase 3 required an initial cycle of CBDCA 250 mg/m2 alone, followed by combination therapy with CBDCA 250 mg/m2 and CSA (8.8, 9.5, or 10.0 mg/kg/d). RESULTS: Preincubation of platinum-resistant A2780 human ovarian cancer cells with CSA 2 micrograms/mL significantly enhanced CBDCA cytotoxicity in clonogenic assays. Fifty-one patients received 130 courses of therapy. The phase 1 MTD was thrombocytopenia (CSA 7.5 mg/kg/d and CBDCA 300 mg/m2) attributable to the effects of CBDCA alone. The phase 2 MTD was reversible nephrotoxicity (serum creatinine elevations to 3.6 and 4.4 mg/dL) and neutropenia (CSA 9.5 mg/kg/d and CBDCA 250 mg/m2). In phase 3, headache was observed in five patients and hypertension in one patient at CSA 10 mg/kg/d. The expected change in platelet count predicted for CBDCA alone was compared with the actual change; no excessive thrombocytopenia was observed with addition of CSA. Steady-state CSA levels of 2 micrograms/mL capable of reversing platinum resistance in vitro were observed. Four objective responses were observed. CONCLUSION: CSA is effective in reversing CBDCA resistance in A2780 ovarian cancer cells. Short-term infusions of CSA < or = 8.8 mg/kg/d in combination with CBDCA are well-tolerated for heavily pretreated patients and result in CSA levels known to reverse CBDCA resistance in vitro.

Therapeutic applications of ribozymes.

The demonstration that RNA can be cleaved by cis or trans ribozymes (catalytic RNAs, RNA enzymes) has potentially important therapeutic implications. Since their discovery in the 1980s, the biochemistry and conserved sequences of ribozymes have been well characterized. Ribozymes are effective modulators of gene expression because of their simple structure, sitespecific cleavage activity, and catalytic potential. The targets of ribozyme-mediated gene modulation have ranged from cancer cells to foreign genes that cause infectious diseases. Additional target sites for ribozymes are in initial phases of development and design. Ribozymes have been targeted against a myriad of genes, including oncogenes (ras, BCR-ABL, c-fos) and drug resistance genes, as well as the human immunodeficiency virus-type I genome. These ribozymes have cleaved the target RNAs in vitro and altered the cellular pathology. Currently, the therapeutic application of ribozymes to human diseases is limited by gene transfer systems. It is anticipated that ribozymes ultimately will play an important role in human gene therapy.

Oligonucleotides as modulators of cancer gene expression.

The delineation of gene function has always been an intensive subject of investigations. Recent advances in the synthesis and chemistry of oligonucleotides have now made these molecules important tools to study and identify gene function and regulation. Modulation of gene expression using oligonucleotides has been targeted at different levels of the cellular machinery. Triplex forming oligonucleotides, as well as peptide nucleic acids, have been used to inhibit gene expression at the level of transcription; after binding of these specific oligonucleotides, conformational change of the DNA's helical structure prevents any further DNA/protein interactions necessary for efficient transcription. Gene regulation can also be achieved by targeting the translation of mRNAs. Antisense oligonucleotides have been used to down-regulate mRNA expression by annealing to specific and determined region of an mRNA, thus inhibiting its translation by the cellular machinery. The exact mechanism of this type of inhibition is still under intense investigation and is thought to be related to the activation of RNase H, a ribonuclease that is widely available that can cleave the RNA/DNA duplex, thus making it inactive. Another well-characterized means of interfering with the translation of mRNAs is the use of ribozymes. Ribozymes are small catalytic RNAs that possess both site specificity and cleavage capability for an mRNA substrate, inhibiting any further protein formation. This review describes how these different oligonucleotides can be used to define gene function and discusses in detail their chemical structure, mechanism of action, advantages and disadvantages, and their applications.

Cisplatin resistance in human cancers.

Cancer chemotherapeutic agents primarily act by damaging cellular DNA directly or indirectly. Tumor cells, in contrast to normal cells, respond to cisplatin with transient gene expression to protect and/or repair their chromosomes. Repeated cisplatin treatments results in a stable resistant cell line with enhanced gene expression but lacking gene amplification for the proteins that will limit cisplatin cytotoxicity. Recently, several new human cell lines have been characterized for cisplatin resistance. These cell lines have led to a better understanding of the molecular and biochemical basis of cisplatin resistance. The c-fos proto-oncogene, a master switch for turning on other genes in response to a wide range of stimuli, has been shown to play an important role in cisplatin resistance both in vitro and in patients. Based on these studies, new strategies have been developed to circumvent and/or exploit clinical cisplatin resistance.

Vitamin D status and associated factors of deficiency among Jordanian children of preschool age.

BACKGROUND/OBJECTIVES: Vitamin D deficiency in children remains a global concern. Although literature exists on the vitamin D status and its risk factors among children in the Middle East, findings have yielded mixed results, and large, representative community studies are lacking. SUBJECTS/METHODS: In a nationally representative survey of 1077 Jordanian children of preschool age (12-59 months) in Spring 2010, we measured 25(OH)D3 concentrations by liquid chromatography-tandem mass spectrometry and calculated prevalence ratios for deficiency associated with various factors. RESULTS: RESULTS showed 19.8% (95% confidence interval (CI): 16.4-23.3%) deficiency (<12 ng/ml) and 56.5% (95% CI: 52.0-61.0%) insufficiency (<20 ng/ml). In adjusted models, prevalence of deficiency was higher for females compared with males (prevalence ratio (PR)=1.74, 95% CI: 1.22-2.47, P=0.002) and lower for children 24-35 months of age (PR=0.64, 95% CI: 0.44-0.92, P=0.018) compared with children 12-23 months of age. In rural areas, there was no difference in prevalence of vitamin D deficiency between those whose mothers had/did not have vitamin D deficiency (P=0.312); however, in urban areas, prevalence of vitamin D deficiency was 3.18 times greater among those whose mothers were vitamin D deficient compared with those whose mothers were not deficient (P=0.000). CONCLUSIONS: Vitamin D deficiency and insufficiency pose significant public health problems in Jordanian children with female children disproportionately affected. Strong associations between vitamin D status in children and urban residency and maternal vitamin D status suggest that the behaviors related to sun exposure in urban mothers likely also affect the sun exposure and thus vitamin D status of their children.

Suppression of the malignant phenotype of melanoma cells by anti-oncogene ribozymes.

The activation of signal transduction pathways by mutation or overexpression of cellular oncogenes has been associated with neoplastic transformation. In this study, we addressed the therapeutic potential of ribozymes targeted against the activated H-ras oncogene as well as against the nuclear proto-oncogenes c-fos and c-myc in the FEM human melanoma cell line containing a H-ras mutation. FEM cells transfected with the anti-ras ribozyme were shown to have the longest doubling time, the least DNA synthesis, and the fewest colonies in soft agar when compared with transfectants with ribozymes against c-fos or c-myc mRNA. Furthermore, anti-ras ribozyme clones showed a dendritic appearance in monolayer culture that was associated with enhanced melanin synthesis. These results suggest that the anti-ras ribozyme could affect not only the proliferation but also the differentiation process of human melanoma cells in vitro. They also reinforce the role of anti-oncogene ribozymes as suppressors of the neoplastic phenotype of melanoma cells.