Correlations of partial and extensive methylation at the p14(ARF) locus with reduced mRNA expression in colorectal cancer cell lines and clinicopathological features in primary tumors

p14(ARF) is a putative tumor suppressor gene thought to modify the levels of p53. CpG sites within the 5'-flanking region and exon 1beta of p14(ARF) are targets of aberrant methylation and transcriptional silencing in human colorectal cancer (CRC). Here we have developed methylation-specific polymerase chain reaction (MSPCR) methods to detect methylation of CpG sites in p14(ARF) in CRC cell lines and primary CRC tumors, and correlated p14(ARF) mRNA expression with methylation in CRC cell lines using competitive quantitative reverse transcription-polymerase chain reaction methods. Ten CRC cell lines were studied; three (DLD-1, HCT15 and SW48) showed extensive methylation and six (Colo320, SW480, HT29, Caco2, SW837 and WiDr) were unmethylated; the other cell line, LoVo, showed partial methylation that affected exon 1beta but not the immediate upstream CpG sites. p14(ARF) mRNA was expressed at extremely low levels in fully methylated cell lines and at 10(4)- to 10(5)-fold higher levels in unmethylated cell lines. p14(ARF) expression in the partially methylated LoVo cell line was intermediate. Treatment of LoVo cells with 2 microM 5-aza-2'-deoxycytidine for 72 h was associated with marked (100-fold) induction of mRNA levels. Of 119 primary CRCs, 18% contained p14(ARF) methylation, although partial methylation was the most common pattern observed (in 67% of methylated tumors). Methylation of p14(ARF) was often accompanied by p16(INK4a) methylation; however, 50% of p14(ARF) methylated tumors contained unmethylated p16(INK4a). Methylation at p14(ARF) was associated with female gender, greater age, proximal anatomic location and poor differentiation, but not stage at diagnosis. A two-step MSPCR method for assaying p14(ARF) methylation in human tumors is described.

The impact of FDG positron emission tomography imaging on the management of lymphomas

The role of 2-(F-18)-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) imaging in the management of patients with lymphoma has been evaluated. 29 patients (12 Hodgkin's disease, 17 non-Hodgkin's lymphoma (NHL)) who underwent FDG-PET imaging during their lymphoma treatment programme were reviewed retrospectively. Correlation between FDG-PET and CT was evaluated, together with the impact upon clinical management of the findings on FDG-PET imaging. FDG-PET added extra information to the findings on clinical examination and CT in 12 patients (41%). This was seen both in patients with negative and positive CT scan. Two false positive FDG-PET scans were seen, reflecting FDG uptake in extranodal sites. Information from FDG-PET imaging resulted in a change in clinical management in 10 patients (34%); in two, initial management was altered, and in eight consolidation therapy after completion of initial chemotherapy was influenced. These changes in clinical management occurred in six patients with high grade NHL, two with low grade NHL and two with Hodgkin's disease. No specific subgroup was identified in whom FDG-PET was particularly discriminant.

Rectal gonorrhoea in homosexual men: source of infection

The objective of this retrospective study was to determine the possible source of infection in homosexual men with rectal gonorrhoea: the probable source of rectal gonorrhoea was identified in 46/155 cases. Although the urethra was the site of infection in 33 (72%) of these contacts, only pharyngeal gonorrhoea was identified in 9 (20%) men. In 25/26 cases, there was concordance in the auxo/serotypes of Neisseria gonorrhoeae between contacts with urethral gonorrhoea and the index men with rectal gonorrhoea. Eleven out of 12 pharyngeal isolates were of the same auxo/serotype as the index cases. This study supports the hypothesis that rectal gonorrhoea in homosexual men can be acquired from the oropharynx. Because infection at this site is an independent risk factor for acquisition of HIV, screening for rectal and pharyngeal gonorrhoea should be offered to men who have sex with men, even when there is no history of unprotected receptive anal intercourse.

Intestinal protozoa in homosexual men in Edinburgh

Our objective was to determine the prevalence of intestinal protozoa in homosexual men attending a sexually transmitted diseases (STD) clinic, to compare it with the prevalence in a previous study from the same clinic, and to examine the relationship, if any, between the presence of protozoa and sexual practices. Men who consecutively attended the clinic and who gave a history of having had recent sexual contact with another male were invited to provide a stool sample for protozoological examination. Diarrhoeal samples were examined by direct microscopy for trophozoites and cysts and, after staining, for Cryptosporidium spp. In all cases, a modified formol-ether method was used to concentrate protozoal cysts before microscopy. One hundred and seventy-five of the 257 men invited to participate in the study provided a stool sample. At least one species of protozoan was found in 99 (57%) men. Giardia intestinalis was identified in only 5 (3%) men. Blastocystis hominis was found in 46 (26%) men, but the presence of this protozoan was not associated with diarrhoea. Other than the prevalence of Entamoeba dispar/histolytica and G. intestinalis, which remained unchanged, the proportion of men who harboured the non-pathogenic protozoa was significantly increased from 1981/82. A correlation between oral-anal sex or peno-insertive or peno-receptive anal intercourse and the prevalence of protozoa was not found. There was also no correlation between the number of species of protozoa carried and these sexual practices. The presence of protozoa was not associated with a history of foreign travel or sexual contact with a man who had recently travelled outside the UK. The study showed that, although the prevalence of infection is low, giardiasis is still transmissible amongst homosexual men. A correlation between individual sexual practices and the prevalence of intestinal protozoa was not found.

An inducible nitric-oxide synthase (NOS)-associated protein inhibits NOS dimerization and activity

A variety of transcriptional and post-transcriptional mechanisms regulate the expression of the inducible nitric-oxide synthase (iNOS, or NOS2). Although neurons and endothelial cells express proteins that interact with and inhibit neuronal NOS and endothelial NOS, macrophage proteins that inhibit NOS2 have not been identified. We show that murine macrophages express a 110-kDa protein that interacts with NOS2, which we call NOS-associated protein-110 kDa (NAP110). NAP110 directly interacts with the amino terminus of NOS2, and inhibits NOS catalytic activity by preventing formation of NOS2 homodimers. Expression of NAP110 may be a mechanism by which macrophages expressing NOS2 protect themselves from cytotoxic levels of nitric oxide.

p53, p21, Rb, and MDM2 proteins in tongue carcinoma from patients < 35 versus > 75 years

Relatively rare squamous cell carcinomas of the tongue in young patients may be associated with different etiologic factors and pathogenetic mechanisms than carcinomas from the same site in older patients. Alterations in cell cycle proteins likely contribute to the biologic behavior of these neoplasms. The purpose of this investigation was to evaluate cell cycle proteins (p53, p21, Rb, MDM2) in lateral tongue cancers from patients at the two ends of the age spectrum. All available archived lateral tongue carcinomas from patients < 35 years (n = 36, 23 males and 13 females) were sectioned, immunohistochemically stained, and evaluated. Protein expression was scored as percent positive nuclei. An equal number of sequentially accessioned lateral tongue specimens from patients > 75 years (23 males and 13 females) were stained and compared. Positive p53 staining was seen in 18/36 of the < 35-year group versus 24/36 of the > 75-year group (p = 0.149). Increased p21 staining (both percent of positive cells and intensity) was evident in 25/32 of the < 35-year group versus 24/32 of the > 75-year group (p = 1.0). Increased p21 expression was seen in both p53-positive and -negative cases in both age groups. Rb protein was increased in 16/29 of the < 35-year group versus 17/26 of the > 75-year group (p = 0.58). Fourteen cases (4/35 vs 10/36, p = 0.135) showed positive MDM2 staining; MDM2-positive cases were also p53 positive in 4/4 younger and 8/10 older patients. We conclude that p53, p21, Rb, and MDM2 are over-expressed in lateral tongue cancers, and that immunohistochemical profiles are heterogeneous. A p53-independent pathway of p21 induction is supported by the results; p53 suppression may be associated with MDM2 protein expression in a subset of cancers. Significant differences in the expression of p53, p21, Rb, and MDM2 proteins are not evident in lateral tongue carcinomas from patients < 35 years as compared to patients > 75 years.

Interaction of interferon regulatory factor-1 and nuclear factor kappaB during activation of inducible nitric oxide synthase transcription

We investigated the molecular mechanism for the synergistic induction of inducible nitric oxide synthase transcription by TNF-alpha and IFN-gamma. Since TNF-alpha and IFN-gamma stimulate cells in part by activating NF-kappaB and IRF-1, we hypothesized that these two transcription factors interact with each other. IRF-1 and NF-kappaB co-localize in the nucleus of stimulated macrophages. Co-immunoprecipitation experiments show that IRF-1 and NF-kappaB interact in stimulated but not resting cells. Super-shift experiments show that IRF-1 and NF-kappaB interact while binding to their respective DNA binding sites. These results demonstrate the existence of a physical interaction between IRF-1 and NF-kappaB proteins in vivo. We next suggested that this interaction between IRF-1 and NF-kappaB bends the DNA of the iNOS promoter region. Using a cyclization assay, we demonstrate that nuclear extracts from stimulated cells accelerate the rate of conversion of a linear to circular DNA, compared to extracts from resting cells. However, stimulated nuclear extracts cannot affect the rate of cyclization of a promoter with a mutant IRE or kappaB site. Furthermore, stimulated nuclear extracts depleted of IRF-1 and NF-kappaB cannot induce cyclization. We conclude that IRF-1 and NF-kappaB interact in vivo, and that this interaction physically bends the indicible nitric oxide synthase promoter DNA. This interaction may explain the mechanism by which IFN-gamma synergistically augments inducible nitric oxide synthase transcription.

Cell cycle proteins and the development of oral squamous cell carcinoma

Expression of cell cycle regulatory proteins was evaluated in premalignant and malignant oral epithelial lesions, to test the hypothesis that protein regulation of the cell cycle may be altered in the development of oral squamous cell carcinoma. Archived paraffin-embedded specimens (n = 90) from 25 patients with recurrent or persistent lesions were evaluated in immunohistochemically stained sections for cell cycle regulatory proteins p53, Rb, Cyclin D1, p27, and p21. The cell cycle was also evaluated by expression of nuclear protein Ki 67. Sections were graded semiquantitatively using a 0-3 + scale to indicate the percentage of positively stained cells. The initial histologic diagnosis for 17/25 patients was either focal keratosis, mild dysplasia, or moderate dysplasia; the initial diagnosis for the remaining eight patients ranged from severe dysplasia to moderately differentiated squamous cell carcinoma. Thirty-three of 90 specimens showed positive p53 expression, 11 of which were dysplasias. Eighty-nine of 90 specimens, from all stages of disease, showed positive Rb expression. Twenty-three of 90 specimens showed positive Cyclin D1 expression, typically in the later stages (carcinoma) of a patient's disease. Eighty-four of 90 specimens showed positive p21 expression; while 55 of 90 specimens were positive for p27. In control mucosa, p27 was highly expressed, while Rb and p21 proteins were expressed at relatively low levels; p53 and Cyclin D1 proteins were largely absent. Generally, staining of p53, Rb, p21, and Ki 67 increased with time in serial biopsies, while p27 showed decreased staining with disease progression. These data show that cell cycle regulatory proteins are altered in both premalignant and malignant disease, and that protein phenotypes are heterogeneous. P53 expression is seen early, and Cyclin D1 expression is seen late in the development of oral premalignant and malignant disease. Expression of p53, Rb, p21 and Ki67 increased, while p27 decreased, with disease progression.

Prognosis in cutaneous T-cell lymphoma by skin stage: long-term survival in 489 patients

BACKGROUND

Although a number of studies have documented the long-term survival of patients with cutaneous T-cell lymphoma (CTCL), none have provided data as to the relative survival of all 4 skin stages.

OBJECTIVE

We document survival of CTCL patients by T stage relative to that of an age-, sex-, and race-matched population.

METHODS

The survival of 489 patients with CTCL registered since 1957 was compared with that of a California control population.

RESULTS

For stage T1 (< 10% skin involved) there was no significant difference between the observed and expected survivals. For the other 3 stages the observed survival was significantly inferior to that of the expected survival (P = .002). At 10 years the relative survivals were: T2 (10% or more skin involved) 67.4%, T3 (tumor stage) 39.2%, T4 (generalized erythroderma) 41.0%. T2 plaque stage patients had an inferior relative survival (P = .001), whereas T2 patch stage patients did not. Lymphadenopathy had an unfavorable impact on prognosis. There was a strong trend toward diagnosing CTCL at an earlier stage in more recent years. We estimate that from 15% to 20% of our patients died of CTCL or related complications.

CONCLUSION

The relative survival of CTCL patients worsens with increasing skin stage, although stages T3 and T4 had closely similar survivals. The great majority of patients with CTCL do not die of their disease.

Kalirin inhibition of inducible nitric-oxide synthase

Nitric oxide (NO) acts as a neurotransmitter. However, excess NO produced from neuronal NO synthase (nNOS) or inducible NOS (iNOS) during inflammation of the central nervous system can be neurotoxic, disrupting neurotransmitter and hormone production and killing neurons. A screen of a hippocampal cDNA library showed that a unique region of the iNOS protein interacts with Kalirin, previously identified as an interactor with a secretory granule peptide biosynthetic enzyme. Kalirin associates with iNOS in vitro and in vivo and inhibits iNOS activity by preventing the formation of iNOS homodimers. Expression of exogenous Kalirin in pituitary cells dramatically reduces iNOS inhibition of ACTH secretion. Thus Kalirin may play a neuroprotective role during inflammation of the central nervous system by inhibiting iNOS activity.

Apoptosis-associated proteins and the development of oral squamous cell carcinoma

Expression of apoptosis-associated proteins was evaluated in premalignant and malignant oral epithelial lesions, to test the hypothesis that protein regulation of apoptosis may be altered in the development of oral squamous cell carcinoma. Ninety archived paraffin-embedded specimens from 25 patients (two or more sequential biopsies each) and eight control specimens were evaluated in immunohistochemically stained sections for tumor suppressor protein p53, p53 binding protein mdm-2, and apoptosis regulatory proteins Bcl-2, Bcl-X, Bax, and Bak. The initial histologic diagnosis for 17/25 patients was either focal keratosis, mild dysplasia, or moderate dysplasia; the initial diagnosis for the remaining eight patients ranged from severe dysplasia to moderately differentiated squamous cell carcinoma. Thirty of 90 specimens showed positive p53 expression, nine of which were dysplasias. In patients with one or more lesions displaying p53 expression, there was increased intensity of staining with disease progression. Bak was expressed in 57/90 specimens, including 27 dysplasias of various grades. There was also a significantly increased intensity of Bak staining with disease progression, which did not appear to be dependent upon p53 status. Bcl-X was expressed in 73/90 specimens, with staining displayed earlier in premalignant lesions than either p53 or Bak. Ten of 90 specimens were positive for Bcl-2 (all were dysplasias or carcinomas), and only 2/90 specimens were positive for Bax. Eleven of 90 specimens were positive for mdm-2; six of which were also positive for p53. These data show that apoptosis-associated proteins are altered in variable patterns in both premalignant and malignant oral epithelial lesions. p53 and especially Bak and Bcl-X are expressed early; Bax is largely absent; and Bcl-2 and mdm-2 show sporadic expression in the development of oral premalignant and malignant disease.

An antiviral mechanism of nitric oxide: inhibition of a viral protease

Although nitric oxide (NO) kills or inhibits the replication of a variety of intracellular pathogens, the antimicrobial mechanisms of NO are unknown. Here, we identify a viral protease as a target of NO. The life cycle of many viruses depends upon viral proteases that cleave viral polyproteins into individual polypeptides. NO inactivates the Coxsackievirus protease 3C, an enzyme necessary for the replication of Coxsackievirus. NO S-nitrosylates the cysteine residue in the active site of protease 3C, inhibiting protease activity and interrupting the viral life cycle. Substituting a serine residue for the active site cysteine renders protease 3C resistant to NO inhibition. Since cysteine proteases are critical for virulence or replication of many viruses, bacteria, and parasites, S-nitrosylation of pathogen cysteine proteases may be a general mechanism of antimicrobial host defenses.

Apoptosis-associated proteins in oral lymphomas from HIV-positive patients

Extranodal oral lymphomas, seen with increasing frequency in HIV infection, may have dysfunctional apoptotic mechanisms that favor tumor progression. The purpose of this study was to evaluate extranodal lymphomas from HIV-positive patients for expression of apoptosis-associated proteins. Correlations were made with 10 histologically comparable extranodal lymphomas from HIV-negative patients and 6 hyperplastic lymph nodes from otherwise healthy young adults. Formalin-fixed tissue sections were immunohistochemically stained for apoptosis-associated proteins (Bcl-2, Bcl-x, Bax, Bak, p53, MDM2, BHRF). In situ hybridization was also done on deparaffinized sections for Epstein-Barr virus EBER mRNA. Eighteen consecutive oral lymphomas were studied in HIV/AIDS-positive patients. Four of 5 intermediate-grade lymphomas expressed Bcl-2 to a greater degree than did high-grade lymphomas (4 of 13). Most lymphomas were positive for Bcl-x and Bax, and few expressed Bak. The staining patterns for these proteins were similar to those seen in HIV-negative patients. Staining patterns were relatively consistent in the hyperplastic lymph nodes, whereas such patterns were irregular in lymphomas. Positive p53 staining was seen in 11 of 18 HIV-positive cases; 9 of these were also MDM2-positive. Double stains suggested that both p53 and MDM2 proteins were expressed in the same cells in these nine cases. Epstein-Barr virus-EBER mRNA was detected in 14 of 18 cases and in 3 of 10 cases from HIV-negative patients. BHRF staining was evident in only a few cells of three HIV-positive lymphomas. The irregular expression of Bcl-2, Bcl-x, Bax, and Bak in oral lymphomas indicates dysfunctional apoptotic mechanisms in these tumors. Bcl-2 staining differs with tumor grade. Positive staining for p53 and MDM2 proteins is a notable feature of lymphomas in HIV-positive patients and may relate to binding of MDM2 to wild-type p53. Epstein-Barr virus is more commonly associated with oral lymphomas in HIV-positive patients, although the Epstein-Barr virus-produced protein BHRF, which has Bcl-2-like activity, is minimally expressed.

HIV infection among homosexual/bisexual males attending genitourinary clinics in Scotland

BACKGROUND

Since 1991, unlinked anonymous HIV testing of homosexual/bisexual males attending genitourinary clinics in Edinburgh and Glasgow has been conducted and resulting prevalence data have been published annually. More detailed information which provides an understanding of what proportion of HIV infected men attending genitourinary clinics in central Scotland (i) remain undetected, (ii) acquire sexually transmitted infections following HIV diagnosis, and (iii) possibly become HIV infected either abroad or following sex with someone from abroad, is reported by the authors.

METHODS

Unlinked anonymous HIV testing of syphilis serology specimens from homosexual/bisexual males attending genitourinary clinics during 1991-5.

RESULTS

Of 3468 specimens tested, 165 (4.8%) were HIV positive. Thirty five per cent (57) of all HIV positive specimens were from men whose infection remained undetected following clinic attendance. Of the 80 attenders who knew themselves to be HIV positive before their clinic visit, 13 had clinical and/or laboratory evidence of a sexually transmitted infection. Men who had a sexual risk associated with America or who were American, had a 2.4-fold greater risk of being HIV infected than those with United Kingdom only connections.

CONCLUSION

Increased efforts should be made to ensure that HIV infected men are diagnosed early after infection and do not engage in high risk sexual behaviour, and that all homosexual men are educated about the particular risks of acquiring HIV infection abroad. More effective interventions to prevent indigenous HIV transmissions need to be developed.

Novel recombinant-antigen enzyme immunoassay for serological diagnosis of syphilis

Enzyme immunoassay (EIA) is an ideal method for screening large numbers of patients for syphilis. We evaluated a novel immune-capture EIA (ICE Syphilis; Murex Diagnostics) that uses three recombinant Treponema pallidum antigens (TpN15, TpN17, and TpN47) and compared the results with those obtained by the native T. pallidum antigen EIA (Captia SelectSyph-G; Centocor) that we currently use for the serodiagnosis of syphilis. Specificity was evaluated by screening 1,184 unselected serum specimens in parallel by the ICE Syphilis and SelectSyph-G assays, while sensitivity was tested with a panel of 101 serum specimens containing antitreponemal antibodies (treated and untreated) from patients with various stages of infection. The specificity of the ICE Syphilis EIA (99.8%) on screening was significantly higher (P < 0.02) than that of the SelectSyph-G EIA (99.2%). The sensitivity of the ICE Syphilis EIA was significantly higher (P < 0.01) than that of the SelectSyph-G EIA on both initial (99 versus 91.4%) and repeat (100 versus 92.4%) testing. The ICE Syphilis EIA was also significantly more sensitive (P < 0.01) than the fluorescent treponemal antibody-abs (92.4%) but not the T. pallidum hemagglutination assay (97.1%). Sera containing antitreponemal antibodies gave a much higher antibody index (absorbance of test serum/kit cutoff) by the ICE Syphilis EIA than by the SelectSyph-G EIA. This combined with the overall high sensitivity makes the ICE Syphilis EIA an ideal test for excluding or detecting treponemal infection in human immunodeficiency virus (HIV)-infected patients. The ICE Syphilis EIA was positive with sera from all 15 HIV-infected patients in the study, whereas sera from 3 HIV-infected patients were negative by the SelectSyph-G EIA. We conclude that the high sensitivity and specificity of the ICE Syphilis EIA and its suitability for automation make it an ideal screening test.

A new recombinant antigen latex agglutination test (Syphilis Fast) for the rapid serological diagnosis of syphilis

We report an assessment of Syphilis Fast, a new latex test that uses a pool of 3 recombinant Treponema pallidum antigens (TpN15, TpN17, and TpN47) for the serodiagnosis of syphilis. Specificity was evaluated by screening 1518 unselected blood specimens in parallel with Syphilis Fast, the Captia SelectSyph-G EIA and the Venereal Disease Research Laboratory (VDRL) cardiolipin antigen test while sensitivity was tested using a panel of 99 treponemal sera (treated and untreated) representing various stages of infection and 15 treponemal sera detected on screening. The specificity of Syphilis Fast on initial testing (99.8%) was significantly higher (P<0.02) than that of Captia SelectSyph-G (99.2%) and the VDRL (99.1%): the specificity of Syphilis Fast remained significantly higher (P<0.02) after repeat testing (respective values 99.9%, 99.5% and 99.4%). There was no difference in the sensitivity of Syphilis Fast and Captia SelectSyph-G on initial (93% vs 92.1%) or repeat (95.6% vs 94.7%) testing: both were significantly more sensitive (P<0.001) than the VDRL (46.5% on initial and 43.9% on repeat testing). The sensitivities of the Treponema pallidum haemagglutination test (TPHA) and FTA-abs were 98.2% and 95.6% respectively. Negative reactions in Syphilis Fast and SelectSyph-G were associated with treated infections and correlated with low TPHA titres (< or = 80). We conclude that Syphilis Fast is a highly specific, simple and fast screening test with a sensitivity comparable to native antigen treponemal tests and that it merits consideration as a front-line screening test.

Anal cytological abnormalities in HIV-infected homosexual men

This study aimed to examine the prevalence of anal cytological abnormalities in groups of HIV-infected and non-infected homosexual men, and to monitor changes with time. Dyskaryosis suggestive of anal intraepithelial neoplasia (AIN) was noted in 24 (30%) of the 80 satisfactory anal smears from 66 HIV-seropositive homosexual men; such changes were found in only 7 (4.7%) of the 149 satisfactory smears from 181 HIV-seronegative homosexual men (P < 0.005), and in none of 34 satisfactory preparations from 51 HIV-seronegative heterosexual men. In the follow-up of 20 HIV-seropositive men, the severity of the cytological abnormalities found in 2 men increased, with the most recent smear showing changes suggestive of AIN III; one of these men subsequently developed anal cancer. Smears from 4 men showed apparent regression in the degree of dyskaryosis. Although the numbers of patients studied were small, there appeared to be a trend towards a more severe degree of dyskaryosis in those men with increasing immunodeficiency. There was no significant difference in the detection of human papillomavirus types 6b, 11, 16 and 18 between HIV-infected and non-infected men.