Characterisation of the interface between nucleophosmin (NPM) and p53: potential role in p53 stabilisation

We have used surface plasmon resonance to quantify the kinetics and stoichiometry of the interaction between p53 and nucleophosmin (NPM). Domains characterising the interface between the two proteins were identified by chemical cross-linking, proteolytic digestion and mass spectrometry based peptide mapping. We show that the C-terminal domain of NPM (residues 242-269) interacts with two regions of p53 (residues 175-196 and residues 343-363) which belong, respectively, to the DNA binding domain and the tetramerisation domain. Potential biological consequences of such interactions are discussed.

Screening for supra-additive effects of cytotoxic drugs and gamma irradiation in an in vitro model for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world. A wide variety of treatment modalities is available for palliative therapy of HCC, although there is no strong evidence that these treatments can have a significant impact on survival. The aim of this work was to screen cytotoxic drugs relevant in the treatment of HCC for enhancement of the effect of irradiation in an in vitro model. As the majority of patients presenting with HCC suffer reduced liver function, attention was paid to low-dose effects of the cytotoxic drugs tested. To reflect this situation in vivo, multicellular tumor aggregates or "spheroids" of HepG2 cells were cultured and exposed to gamma irradiation alone or in combination with cisplatin for 4 h, gemcitabin for 4 or 24 h, or 5-fluorouracil for 4 h. In one experiment, the spheroids were cultured for 4 weeks in multiwell plates that allowed adhesion. Measurement of two-dimensional spheroid outgrowth was made every week for each spheroid. This kind of growth depends on the proliferation and motility of the cells that form the spheroid. In a second experiment, toxicity was evaluated by comparative growth curves by means of a three-dimensional growth assay and by histology. Supra-additive effects lasting for 4 weeks were observed for all drugs tested in combination with a gamma irradiation of 10 Gy.

Gastrostomy tube feeding in children with cerebral palsy: a prospective, longitudinal study

We report a longitudinal, prospective, multicentre cohort study designed to measure the outcomes of gastrostomy tube feeding in children with cerebral palsy (CP). Fifty-seven children with CP (28 females, 29 males; median age 4y 4mo, range 5mo to 17y 3mo) were assessed before gastrostomy placement, and at 6 and 12 months afterwards. Three-quarters of the children enrolled (43 of 57) had spastic quadriplegia; other diagnoses included mixed CP (6 of 57), hemiplegia (3 of 57), undiagnosed severe neurological impairment (3 of 57), ataxia (1 of 57), and extrapyramidal disorder (1 of 57). Only 7 of 57 (12%) could sit independently, and only 3 of 57 (5%) could walk unaided. Outcome measures included growth/anthropometry, nutritional intake, general health, and complications of gastrostomy feeding. At baseline, half of the children were more than 38D below the average weight for their age and sex when compared with the standards for typically-developing children. Weight increased substantially over the study period; the median weight z score increased from -3 before gastrostomy placement to -2.2 at 6 months and -1.6 at 12 months. Almost all parents reported a significant improvement in their child's health after this intervention and a significant reduction in time spent feeding. Statistically significant and clinically important increases in weight gain and subcutaneous fat deposition were noted. Serious complications were rare, with no evidence of an increase in respiratory complications.

Impact of gastrostomy tube feeding on the quality of life of carers of children with cerebral palsy

The aim of this prospective cohort study was to evaluate the impact of gastrostomy tube feeding on the quality of life of carers of children with cerebral palsy (CP). Short-Form 36 version II was used to measure quality of life in carers of 57 Caucasian children with CP (28 females, 29 males; median age 4y 4mo, range 5mo to 17y 3mo) six and 12 months after insertion of a gastrostomy tube. Responses were calibrated against a normative dataset (Oxford Healthy Life Survey III). Six months after gastrostomy feeding was started, a substantial rise in mean domain scores for mental health, role limitations due to emotional problems, physical functioning, social functioning, and energy/vitality were observed. At 12 months after gastrostomy placement, carers reported significant improvements in social functioning, mental health, energy/vitality (mean increase >9.8 points;p<0.03), and in general health perception (mean increase 6.35 points;p=0.045) compared with results at baseline. Moreover, the values obtained for these domains at 12 months were not significantly different from the normal reference standard. Carers reported a significant reduction in feeding times, increased ease of drug administration, and reduced concern about their child's nutritional status. This study has demonstrated a significant, measurable improvement in the quality of life of carers after insertion of a gastrostomy feeding tube.

Laminarin elicits defense responses in grapevine and induces protection against Botrytis cinerea and Plasmopara viticola

Grapevine (Vitis vinifera L.) is susceptible to many pathogens, such as Botrytis cinerea, Plasmopara viticola, Uncinula necator, and Eutypa lata. Phytochemicals are used intensively in vineyards to limit pathogen infections, but the appearance of pesticide-resistant pathogen strains and a desire to protect the environment require that alternative strategies be found. In the present study, the beta-1,3-glucan laminarin derived from the brown algae Laminaria digitata was shown both to be an efficient elicitor of defense responses in grapevine cells and plants and to effectively reduce B. cinerea and P. viticola development on infected grapevine plants. Defense reactions elicited by laminarin in grapevine cells include calcium influx, alkalinization of the extracellular medium, an oxidative burst, activation of two mitogen-activated protein kinases, expression of 10 defense-related genes with different kinetics and intensities, increases in chitinase and beta-1,3-glucanase activities, and the production of two phytoalexins (resveratrol and epsilon-viniferin). Several of these effects were checked and confirmed in whole plants. Laminarin did not induce cell death. When applied to grapevine plants, laminarin reduced infection by B. cinerea and P. viticola by approximately 55 and 75%, respectively. Our data describing a large set of defense reactions in grapevine indicate that the activation of defense responses using elicitors could be a valuable strategy to protect plants against pathogens.

Noninvasive measurement of viscosity from damping of capillary waves

Capillary waves are surface waves on fluids with wavelengths in the millimeter range. The determination of viscosity from the damping of capillary waves is of great practical importance as it affords the possibility of measuring the viscosity of fluids noninvasively. In this paper a noncontact method for generation and detection of capillary waves on fluid is described. A miniature laser interferometer is employed to measure noninvasively the wave amplitude and its attenuation with a resolution of about 10 nm. As a test case, the attenuation data for capillary waves on pure water are used to obtain the kinematic viscosity of water as a function of temperature. The results compare favorably with the most reliable published data on the subject.

18FDG PET versus high-dose 67Ga scintigraphy for restaging and treatment follow-up of lymphoma patients

To date, only one published study has directly compared 67Ga scintigraphy (low dose, planar) with planar dual-head gamma camera 18F-fluorodeoxyglucose (18FDG) imaging for the purpose of treatment follow-up monitoring in lymphoma patients, and no data on restaging are available. The present study reports the direct comparison of high-dose (297-370 MBq) 67Ga planar and single photon emission computed tomography (SPECT) imaging and conventional 18FDG positron emission tomography (PET) for restaging and treatment follow-up of lymphoma patients versus a gold standard consisting of morphological imaging, including plain radiography and computed tomography (CT) scanning, bone marrow examination and long-term follow-up (<12 months). Sixteen patients, 10 with non-Hodgkin's lymphoma and six with Hodgkin's disease, were included (10 men, six women; median age, 43 years; range, 16-64 years). The median follow-up time was 27 months (range, 12-34 months). In two patients, 67Ga and 18FDG PET (370 MBq) were performed twice, resulting in 18 cross-sectional episodes. In 11 episodes, the results obtained by both imaging modalities were in agreement with regard to the presence or absence of disease when compared with the gold standard. However, the abnormalities found on 18FDG PET were always more extensive. In two episodes, 67Ga imaging normalized after treatment, whereas PET showed significant regression followed by subsequent normalization. In four additional episodes, 67Ga images were negative, whereas 18FDG PET visualized non-tumour-related pathology, such as lung infection, rib fracture or dense thymic tissue. In one gold standard-negative patient, the underlying cause of sternal FDG uptake remained undetermined. The data presented, although limited in number, suggest that 18FDG PET performs better than Ga imaging in monitoring lymphoma disease status. However, a correlation with clinical history and a knowledge of the characteristics of benign lesions are mandatory. Further studies are recommended.

Quality of life assessment in radionuclide therapy: a feasibility study of the EORTC QLQ-C30 questionnaire in palliative (131)I-lipiodol therapy

The good tolerance of radionuclide therapy has frequently been proposed as a major advantage. This study explored the feasibility of using the EORTC QLQ-C30 questionnaire in palliative iodine-131 lipiodol therapy for hepatocellular carcinoma. Questionnaires were completed during interviews in which all symptoms, co-morbidity and medication were assessed at baseline within 1 week before (131)I-lipiodol therapy, and subsequently after 1 and 3 months, in 20 patients treated with locoregional, intra-arterial (131)I-lipiodol therapy with or without cisplatin. Principal observations were that (1) a number of important scales, i.e. overall quality of life, physical functioning and pain, worsened between 0 and 3 months after (131)I-lipiodol therapy, irrespective of tumour response, and (2) the occurrence of clinical side-effects was associated with a negative impact on quality of life and physical functioning 1 and 3 months after (131)I-lipiodol. The QLQ-C30 can be regarded as a feasible method for quality of life assessment in (131)I-lipiodol therapy for hepatocellular carcinoma and possibly in other radionuclide therapies. These observations should be related to the impact of other treatment modalities on quality of life.

Biomarkers of genotoxicity of urban air pollution. Overview and descriptive data from a molecular epidemiology study on populations exposed to moderate-to-low levels of polycyclic aromatic hydrocarbons: the AULIS project

Epidemiologic studies indicate that prolonged exposure to high pollution levels is associated with increased risk of cancer, especially lung cancer. However, under conditions of moderate or low air pollution, epidemiologic evidence does not permit reliable conclusions. Biomarker-based population studies may serve as complementary tools providing a better understanding of the relative contribution of ambient atmospheric pollution to the overall genotoxic burden suffered by city dwellers. However, past efforts to apply biomarkers to studies of low levels exposure to urban air pollution have given inconclusive results, partly because of the absence of adequate data on personal exposure, covering a time-window which is appropriate for the biomarkers being examined, as well as a battery of biomarkers reflecting different stages of the carcinogenic process. In the present paper, the potential of biomarker-based population studies to aid the assessment of the genotoxic and carcinogenic effects of urban air pollution is reviewed by reference to the achievements and limitations of earlier reported studies. The design and methodology adopted in a recently completed large-scale population study, carried out in the context of the European Union Environment and Climate Programme, known by the short name of AULIS project, is discussed and descriptive statistics of the main findings of the project are presented. These findings indicate that for cohorts suffering moderate-to-low exposures to airborne particulate-bound polycyclic aromatic hydrocarbons (PAHs), no simple correlation with biomarkers of genotoxicity existed and suggest that additional factors made a significant contribution to the overall genotoxic burden.

XPD exon 10 and 23 polymorphisms and DNA repair in human skin in situ

Forty-four Finnish volunteers who were previously studied with regard to the repair rate of UV-specific cyclobutane pyrimidine dimers in the skin were genotyped for XPD polymorphisms at codons 312 (exon 10 G-->A, Asp-->Asn) and 751 (exon 23 A-->C, Lys-->Gln). The repair rate was measured at 24 h for two different cyclobutane dimers. The data did not show consistent XPD genotype-specific differences in DNA repair rates among all subjects. The combined exon 10 AA and exon 23 CC genotype was associated with an approximately 50% depression of repair rate but this was of borderline statistical significance. However, the exon 23 C allele was associated with depressed repair among subjects aged 50 years or older and the result was consistent with both dimers.

The anti-tumoral activity of neoadjuvant intra-arterial 131I-lipiodol treatment for hepatocellular carcinoma: a pilot study

BACKGROUND

The high recurrence rate after curative resection has stimulated the development of adjuvant treatment modalities, such as local embolization. This study was set up to investigate the anti-tumoral potential of neo-adjuvant 131I-lipiodol administration before liver transplantation.

METHODS

In this preliminary, prospective study we treated 10 consecutive HCC patients by intra-arterial injection of 131I-lipiodol into the hepatic artery followed by liver transplantation within 1-9 months (mean 3.4). After hepatic catheterization, 1332-2146 MBq (mean 1887 MBq) or 36-58 mCi (mean 51 mCi) was instilled as selective as possible, depending on the distribution of the tumors: non-selectively in the hepatic artery propria (n = 4), selectively in the right and/or left hepatic artery (n = 3) or super-selectively in segmental arteries (n = 3).

RESULTS

Anti-tumoral activity was regarded as obvious with 1) a strong decrease of alfa-fetoprotein (AFP), comparing the highest recorded value before and after 131I-lipiodol and/or 2) a downstaging in TNM classification on the posttherapy MRI as compared to the pre-therapy MRI and/or 3) tumors with > 50% necrosis on histo-pathology of the explanted liver, without previous chemoembolization. Either of these criteria were met by 5/10 (50%) of patients. A 4) downstaging in pTNM classification on histopathology compared to the TNM classification of the MRI and/or a 5) tumor necrosis of only 10-50% were regarded as possibly tumor-related but were not accepted as a single criteria of anti-tumoral activity. This was seen in 3/10 (30%) of patients. Clinical side-effects of the 131I-lipiodol therapy were generally mild with a temperature rise in two cases, nausea without vomiting in another two and upper back pain in one patient. In one patient progressive liver failure developed one week after 131I-lipiodol therapy necessitating premature liver transplantation after 4 weeks.

CONCLUSION

With the use of stringent anti-tumoral criteria, this study shows evidence of an anti-tumoral effect in 50% of patients. Our data support the evaluation on larger patient numbers to confirm the promising anti-tumoral activity of 131I-lipiodol in HCC patients candidated for liver transplantation.

Differential long-term effects of tannic acid on adenyl cyclase activity and lipolysis in rat adipocytes

Plants elaborate a variety of secondary metabolites such as hydrolysable tannins which are relatively abundant in fruits, vegetables and beverages in the human diet. We have studied the in vivo long-term effect consumption of tannic acid-supplemented drinking water (0.05%, w/v) on the rat adipocyte adenyl cyclase system and on lipolysis. We found that 14-day tannic acid supplementation did not significantly affect either body growth or food consumption, while fat pads weight was higher than that of the control, although the difference was not significant. On the other hand, tannic acid supplementation decreased both basal and isoproterenol-stimulated lipolysis significantly whereas cyclic AMP production as well as adenyl cyclase activity increased significantly. These results are at a first glance contradictory as cyclic AMP accumulation and lipolysis are positively correlated in rat adipocytes. They suggest at least that the tannic acid diet led to an inhibition of cyclic AMP-dependent protein kinase activity followed by a decrease in lipolysis in rat adipocytes, and to an increased activity of the type VI adenyl cyclase subunit of rat fat cells. This subunit is known to be negatively regulated under phosphorylation by cyclic AMP-dependent protein kinase. More in-depth studies are required to examine whether tannic acid could at least modify the expression of the catalytic subunit of adenyl cyclase, G-proteins and cyclic AMP-dependent protein kinase and/or alter their activities.

Particular biochemical profiles for enterohemorrhagic Escherichia coli O157:H7 isolates on the ID 32E system

The ability of the ID 32E system to identify and discriminate 74 Escherichia coli O157 isolates among 106 E. coli non-O157 isolates was evaluated. The results showed atypical biochemical reactions but accurate identification at the species level and no unique biochemical profile numbers for E. coli O157, although these numbers were distinct from those of other serotypes.

Differential interactions between GSTM1 and NAT2 genotypes on aromatic DNA adduct level and HPRT mutant frequency in lung cancer patients and population controls

We have studied the influence of GSTM1 and NAT2 genotypes on aromatic DNA adduct level (AL) and HPRT mutant frequency (MF) in smokers with newly diagnosed lung cancer and matched population controls. AL was analyzed in relation to genotypes in 170 cases and 144 controls (113 current/recent smokers and 201 former/never smokers), and MF in 157 cases and 152 controls (155 ever smokers and 154 never smokers). Both genotypes exhibited the a priori expected effects on AL and MF among controls only, especially among smoking controls [significantly lower pack-years (a pack-year is defined as 1 pack of cigarettes/day for 1 year) than among cases]. Among the 42 currently smoking controls, the NAT2 slow genotype [odds ratio (OR), 7.5; 95% confidence interval (CI), 1.5-38.4], in particular in combination with the GSTM1 null genotype (OR, 19.3, 95% CI, 1.1-338.6 for null/slow versus positive/rapid) was strongly associated with high AL. The null/slow combination was also significantly associated with high MF among ever smokers (cases and controls pooled) with lower pack-years (OR, 3.7; 95% CI, 1.3-10.7 versus all of the other genotypes; OR, 5.1; 95% CI, 1.2-22.4 versus positive/rapid). In contrast, an antagonistic gene-gene interaction was seen among smoking cases for both AL and MF. Only currently smoking cases with the combined GSTM1 null and NAT2 rapid genotype showed a positive correlation between InAL and InMF (r, 0.64; P = 0.1), and an increase of AL with both age and daily cigarette use. This genotype combination was also associated with high MF among ever-smoking cases (OR, 4.0; 95% CI, 0.9-17.7 versus positive/rapid). There was a significant interaction between NAT2 genotype and pack-years of smoking among cases, so that the rapid genotype was associated with high MF among ever-smoking cases diagnosed at higher pack-years, whereas the slow genotype was associated with high MF at lower pack-years. These findings suggest that the influence of NAT2 genotype on AL and MF and its interaction with GSTM1 genotype may be dose dependent. The NAT2 slow genotype, in particular when combined with the GSTM1 null genotype, may confer increased susceptibility to adduct formation, gene mutation, and lung cancer when the smoking dose is low.

Compared randomized roles and pain factor by Vabra and Wallach Endocell in endometrial evaluation

This randomized study was carried out to compare pain factors of Vabra and Endocell by an ordered classification of one to ten to evaluate the respective pathological yield and to establish the clinical acceptability. Patients had endometrial evaluation either for abnormal bleeding, abnormal endometrial line as demonstrated by echography or abnormal endometrial cells in the Pap smear. Age, gravidity, parity and hysterometry were similar in both groups, with abnormal bleeding being the most frequent indication (250/370 patients, 67.5%). Both techniques yielded equal results for insufficient tissue retrieval at 46/184 (25.0%) for Vabra and at 50/183 (27.3%) for Endocell. The pain score differed significantly in favor of Wallach Endocell at 4.36+/-2.38 versus Vabra at 5.65+/-2.41 (p=0.001). Vabra and Endocell give similar pathological results; however, Endocell is significantly less painful and easier to manipulate and carry because of its weight (1.69 g vs. 37.80 g).

Prevalence and severity of feeding and nutritional problems in children with neurological impairment: Oxford Feeding Study

The aim of this study was to estimate the prevalence and severity of feeding and nutritional problems in children with neurological impairment within a defined geographical area. In a cross-sectional study, a validated questionnaire was sent to 377 parents of children (aged 4 to 13 years) on the Oxford Register of Early Childhood Impairments with oromotor dysfunction. The return rate was 72%. Of these, 93% had cerebral palsy; 47% were unable to walk; 78% had speech difficulty; and 28% continuous drooling of saliva. Gastrointestinal problems were commonly encountered: 59% were constipated; 22% had significant problems with vomiting, and 31% had suffered at least one chest infection in the previous 6 months. Feeding problems were prevalent: 89% needed help with feeding and 56% choked with food; 20% of parents described feeding as stressful and unenjoyable. Prolonged feeding times (3h/day) were reported by 28%. Only 8% of participants received caloric supplements and 8% were fed via gastrostomy tube. Even though 38% of respondents considered their child to be underweight, 64% of children had never had their feeding and nutrition assessed. The results highlight that feeding problems in children with neurological impairment are common and severe, causing parental concern. Many of these children would benefit from nutritional assessment and management as part of their overall care.

Hydrogen peroxide induced mutations at the HPRT locus in primary human T-lymphocytes

Reactive oxygen species (ROS) produced by intracellular metabolism are believed to contribute to spontaneous mutagenesis in somatic cells. Hydrogen peroxide (H(2)O(2)) has been shown to induce a variety of genetic alterations, probably by the generation of hydroxyl radicals via the Fenton reaction. The kinds of DNA sequence alterations caused by H(2)O(2) in prokaryotic cells have been studied extensively, whereas relatively little is known about the mutational spectrum induced by H(2)O(2) in mammalian genes. We have used the T-cell cloning assay to study the ability of H(2)O(2) to induce mutations at the hypoxanthine guanine phosphoribosyltransferase (HPRT) locus in primary human lymphocytes. Treatment of cells for 1 h with 0.34-1.35 mM of H(2)O(2) caused a dose dependent decrease of cell survival and increase of the HPRT mutant frequency (MF). After 8 days of expression time, the highest dose of H(2)O(2) caused a 5-fold increase of MF compared to the untreated control cells. Mutant clones were collected and the genomic rearrangements at the T-cell receptor (TCR) gamma-locus were studied to identify independent mutations. RT-PCR and DNA sequencing was used to identify mutations in the HPRT coding region. Due to a relatively high frequency of sibling clones, only six independent mutations were obtained among the controls, and 20 among the H(2)O(2) treated cells. In both sets, single base pair substitutions were the most common type of mutation (5/6 and 13/20, respectively), with a predominance of transitions at GC base pairs, which is also the most common type of HPRT mutation in T-cells in vivo. Among the single base pair substitutions, five were new mutations not previously reported in the human HPRT mutation database. Overall, the kinds of mutation occurring in T-cells in vivo and H(2)O(2) treated cells were similar, albeit the number of mutants was too small to allow a meaningful statistical comparison. These results demonstrate that H(2)O(2) is mutagenic to primary human T-lymphocytes in vitro and induces mutations of the same kind that is observed in the background spectrum of HPRT mutation in T-cells in vivo.

Identification of in vivo mutations in exon 5 of the human HPRT gene in a set of pooled T-cell mutants by constant denaturant capillary electrophoresis (CDCE)

Constant denaturant capillary electrophoresis (CDCE), based on co-operative DNA melting equilibria, has the resolving power to separate single nucleotide mutants from wild type sequences. We used this technique to study mutations in a 70-bp isomelting domain of the human HPRT gene, which included the entire exon 5 and its flanking splice donor and acceptor sites. Pooled samples of 6-thioguanine selected T-cell clones from 51 healthy donors representing a total of approximately 1000 individual HPRT mutants were analysed. Slow moving peaks from the heteroduplex part of the CDCE electropherograph were collected and subjected to a second round of PCR and CDCE analysis, followed by DNA sequencing. Five independent mutations were detected. Four were splicing errors; one insertion of CC and two G-->A transitions in the splice donor site of intron 5, and one G-->C transversion in the splice acceptor site of intron 4. The fifth mutation was a missense transversion, T389>G. A reconstruction experiment, in which DNA with known mutation was mixed with wild type DNA, showed the sensitivity of mutation detection to be better than 1:100 under the conditions used in this study. These results demonstrate the high sensitivity of the CDCE-method for mutation screening.

Endocervical curettage in cervical evaluation

OBJECTIVE

To evaluate the role of endocervical curettage (ECC) in the diagnosis of cervical intraepithelial neoplasia.

MATERIALS AND METHODS

Retrospectively we studied 581 patients who had ECC, 43 (7.4%) had cervical intraepithelial lesions (CIN) 1 ECC, 23 (4.0%) CIN 2-3 ECC, and 515 negative ECC (88.6%). Analysis of variance was used to compare for age and parity, and Pearson's chi-square test was used to analyze the association with other variables such as cytology, images, acetowhite epithelium, microbiopsy, and ECC. Significance level was set at p = 0.05.

RESULTS

Age for CIN 1 ECC was at 32.3 (16-66) years; parity was at 0.82 (parity 0-7) compared with 35.2 (18-70) years and parity at 1.52 (parity 0-12) for CIN 2-3 ECC, and 36.1 (14-68) years, parity at 1.1 (parity 0-10) for negative ECC. ECC is associated with Cytobrush cytology (Zelsmyr Cytobrush, International Cytobrush Inc., Hollywood. FL) (p = 0.000) in CIN 2-3 ECC and high-grade squamous intraepithelial lesion (HGSIL) cytology. Positive ECC was not overrepresented in unsatisfactory colposcopy (14/61, 23%) compared with negative ECC (158/526, 30%, p = 0.43). If positive ECC is not associated with the presence of significant acetowhite epithelium, a net association (p = 0.000) was observed between CIN 1 microbiopsies and CIN 1 ECC 9 (12/19), and CIN 2-3 biopsies and CIN 2-3 ECC (12/17). Conization for CIN 2-3 ECC (n = 23) yielded 15 CIN 2-3, two CIN 1, one microinvasive cervical cancer, one cancer of the cervix, and four negative cones.

CONCLUSIONS

Positive endocervical curettage is associated with endocervical cytology and microbiopsy. In ablative treatments, when low-grade squamous intraepithelial lesion (LGSIL) smear, satisfactory colposcopy, and CIN 1 biopsy is observed, ECC appears unnecessary since CIN 2-3 ECC was not observed in these patients. All other cases should have ECC prior to ablative therapy. CIN 2-3 ECC, commands conization, in order to eliminate invasive cancer, and confirm and treat CIN 2-3. ▪.

Mutational spectra at the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus in T-lymphocytes of nonsmoking and smoking lung cancer patients

Molecular analysis of mutations at the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus in peripheral blood T-lymphocytes can provide information on mechanisms of somatic in vivo mutation in populations exposed to exogenous carcinogens and in individuals with inherent susceptibility to cancer and other diseases. To study possible mutational changes associated with smoking as a risk factor for lung cancer, we analyzed HPRT mutations in T-cells of newly diagnosed, nonsmoking and smoking lung cancer patients before treatment. Reverse transcriptase polymerase chain reaction (RT-PCR) and DNA sequencing methods were used to identify 146 independent mutations, 73 each from 32 nonsmoking and 31 smoking cases. In 35 T-cell mutants, the HPRT cDNA showed loss of an entire exon, indicating a splicing mutation. Among the remaining 111 fully characterized mutations in the coding region, single base pair (bp) substitutions predominated with 79% (48/61) in nonsmokers and 90% (45/50) in smokers. Frameshift and small deletion (1-24 bp) mutations were found in 18 mutants. The distribution of base pair substitutions was nonrandom, with significant clustering at previously identified hotspot positions 143, 197 and 617 in the HPRT coding sequence (P< or =0.008). One additional hotspot, GC-->TA at position 606, was observed only in smokers (P=0.006). The frequency of GC>TA transversions was higher in smokers (13%) than in nonsmokers (6%). Conversely, smokers had a lower frequency of GC>AT transitions (24%) than nonsmokers (35%). This smoking-associated shift of the HPRT mutational spectrum, although not statistically significant, is consistent with the in vitro mutagenicity of benzo(a)pyrene (BaP), a prominent carcinogen of tobacco smoke, and with known differences in the TP53 mutational spectrum in lung tumors of smokers and nonsmokers. Among nonsmokers, the HPRT mutational spectra in healthy population controls and lung cancer patients were similar, but there was a marginally significant difference (P=0.07) in the distribution of base pair substitutions between smoking controls and patients. These results suggest that (i) general mechanisms of somatic mutagenesis in individuals with possible predisposition to cancer (e.g. nonsmoking lung cancer patients) are not different from those in normal healthy individuals, and (ii) the HPRT gene in T-cells is a useful reporter locus for smoking-associated somatic in vivo mutations occurring early in lung cancer development.