Molecular variants of human papillomavirus type 16 from four continents suggest ancient pandemic spread of the virus and its coevolution with humankind

We have amplified by the polymerase chain reaction, cloned, and sequenced genomic segments of 118 human papillomavirus type 16 (HPV-16) isolates from 76 cervical biopsy, 14 cervical smear, 3 vulval biopsy, 2 penile biopsy, 2 anal biopsy, and 1 vaginal biopsy sample and two cell lines. The specimens were taken from patients in four countries--Singapore, Brazil, Tanzania, and Germany. The sequence of a 364-bp fragment of the long control region of the virus revealed 38 variants, most of which differed by one or several point mutations. Phylogenetic trees were constructed by distance matrix methods and a transformation series approach. The trees based on the long control region were supported by another set based on the complete E5 protein-coding region. Both sets had two main branches. Nearly all of the variants from Tanzania were assigned to one (African) branch, and all of the German and most of the Singaporean variants were assigned to the other (Eurasian) branch. While some German and Singaporean variants were identical, each group also contained variants that formed unique branches. In contrast to the group-internal homogeneity of the Singaporean, German, and Tanzanian variants, the Brazilian variants were clearly divided between the two branches. Exceptions to this were the seven Singaporean isolates with mutational patterns typical of the Tanzanian isolates. The data suggest that HPV-16 evolved separately for a long period in Africa and Eurasia. Representatives of both branches may have been transferred to Brazil via past colonial immigration. The comparable efficiencies of transfer of the African and the Eurasian variants to the New World suggest pandemic spread of HPV-16 in past centuries. Representatives of the African branch were possibly transferred to the Far East along old Arab and Indonesian sailing routes. Our data also support the view that HPV-16 is a well-defined virus type, since the variants show only a maximal genomic divergence of about 5%. The small amount of divergence in any one geographic location and the lack of marked divergence between the Tanzanian and Brazilian African genome variants two centuries after their likely introduction into the New World suggest a very slow rate of viral evolution. The phylogenetic tree therefore probably represents a minimum of several centuries of evolution, if not an age equal to that of the respective human races.

Sequence variants of human papillomavirus type 16 in clinical samples permit verification and extension of epidemiological studies and construction of a phylogenetic tree

Genomic variability between different viral isolates provides a powerful epidemiological tool for verifying ultrasensitive diagnostic procedures, understanding infectious pathways in individuals and human populations, and studying viral evolution. The potential of this approach has not yet been exploited for the diagnosis of human papillomaviruses (HPVs) like HPV type 16 (HPV-16), which are involved in genital cancer. Toward this end, we amplified by polymerase chain reaction, cloned, and sequenced a 364-bp noncoding segment of the HPV-16 genome from cell lines, cervical biopsy specimens, and cervical smears. The HPV-16 genomes in the cell lines SiHa and CaSki showed an identical point mutation, and in the SiHa cell line it had an additional 38-bp deletion. Only 4 of 22 cervical lesions biopsied from patients at several hospitals in Singapore contained HPV-16 DNA with the prototype sequence, while the DNAs of the other 18 cervical lesions differed by 1 to 10 mutations. This excludes contaminations with cloned HPV-16 DNA as the source of this DNA. To test whether this diversity was a geographic idiosyncrasy, we analyzed 25 cervical biopsy specimens from Brazil. Eight of these contained the prototype sequence, while 17 were mutated. Altogether, 11 genomic variants were found in the Singaporean samples and 12 genomic variants were found in the Brazilian samples, and only 5 of these occurred identically in both cohorts. All variants could be connected to form a phylogenetic tree, with some branches being specific for each cohort. This suggests that the variants did not originate over a short period in the individual patient but, rather, evolved consecutively while spreading throughout humankind.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic gene expression signature for high-grade serous ovarian cancer

BACKGROUND

Median overall survival (OS) for women with high-grade serous ovarian cancer (HGSOC) is ∼4 years, yet survival varies widely between patients. There are no well-established, gene expression signatures associated with prognosis. The aim of this study was to develop a robust prognostic signature for OS in patients with HGSOC.

PATIENTS AND METHODS

Expression of 513 genes, selected from a meta-analysis of 1455 tumours and other candidates, was measured using NanoString technology from formalin-fixed paraffin-embedded tumour tissue collected from 3769 women with HGSOC from multiple studies. Elastic net regularization for survival analysis was applied to develop a prognostic model for 5-year OS, trained on 2702 tumours from 15 studies and evaluated on an independent set of 1067 tumours from six studies.

RESULTS

Expression levels of 276 genes were associated with OS (false discovery rate < 0.05) in covariate-adjusted single-gene analyses. The top five genes were TAP1, ZFHX4, CXCL9, FBN1 and PTGER3 (P < 0.001). The best performing prognostic signature included 101 genes enriched in pathways with treatment implications. Each gain of one standard deviation in the gene expression score conferred a greater than twofold increase in risk of death [hazard ratio (HR) 2.35, 95% confidence interval (CI) 2.02-2.71; P < 0.001]. Median survival [HR (95% CI)] by gene expression score quintile was 9.5 (8.3 to -), 5.4 (4.6-7.0), 3.8 (3.3-4.6), 3.2 (2.9-3.7) and 2.3 (2.1-2.6) years.

CONCLUSION

The OTTA-SPOT (Ovarian Tumor Tissue Analysis consortium - Stratified Prognosis of Ovarian Tumours) gene expression signature may improve risk stratification in clinical trials by identifying patients who are least likely to achieve 5-year survival. The identified novel genes associated with the outcome may also yield opportunities for the development of targeted therapeutic approaches.

A comparative study of the clinicopathological significance of E-cadherin and catenins (alpha, beta, gamma) expression in the surgical management of oral tongue carcinoma

PURPOSE

E-cadherin and catenins are important epithelial adhesion molecules in normal epithelium. Loss of E-cadherin-catenin adhesion is an important step in the progression of many epithelial cancers. E-cadherin and catenins expression in carcinoma of the tongue were evaluated in relation to their clinicopathological features and prognostic values.

METHOD

Immunohistochemical staining was carried out with E-cadherin and (alpha, beta, gamma)-catenin monoclonal antibodies for 85 surgical specimens of oral tongue carcinoma, nine matched metastatic lymph nodes, and seven locally recurrent tumours.

RESULTS

There was under-expression in 85% of E-cadherin, 94% of alpha-catenin, 89% of beta-catenin, and 83% of gamma-catenin in the primary tumours. There was no correlation of E-cadherin/catenin expression with sex, age, cancer stage, and differentiation. Nodal metastasis was found in 68% of patients with weak expression of gamma-catenin compared with 9% with strong expression in primary tumours (chi-square, P = 0.02). E-cadherin was a significant prognostic factor for survival and recurrence; patients with weak E-cadherin expression had 53% 5-year survival compared with 85% with strong expression (Wilcoxon, P = 0.0159).

CONCLUSIONS

Both E-cadherin and catenins were highly under-expressed in oral tongue carcinoma, metastatic lymph node, and recurrent tumour. gamma-catenin had predictive value for nodal metastasis. E-cadherin was, however, a more important prognostic factor for recurrence and survival.

Phase 1 dose-escalation study of CP-690 550 in stable renal allograft recipients: preliminary findings of safety, tolerability, effects on lymphocyte subsets and pharmacokinetics

CP-690 550 inhibits Janus kinase 3 with nanomolar potency. In this dose-escalation study, we assessed the safety, tolerability, effects on lymphocyte subsets, and pharmacokinetics of CP-690 550 when coadministered with mycophenolate mofetil in stable renal allograft recipients for 28 days. Twenty-eight patients were enrolled. Six patients received CP-690 550 5 mg twice daily (BID), 6 patients received 15 mg BID, 10 patients received 30 mg BID, and 6 patients received placebo. The most frequent adverse events were infections and gastrointestinal (abdominal pain, diarrhea, dyspepsia, and vomiting). CP-690 550 15 mg BID and 30 mg BID were associated with a mean decrease in hemoglobin from baseline of 11% and a mean decrease in absolute natural killer cell counts of 50%. CP-690 550 30 mg BID was also associated with a mean increase in absolute CD19(+) B-lymphocytes of 130%. There were no changes in the number of neutrophils, total lymphocytes, platelets, or CD4(+) or CD8(+) T cells; clinical chemistry; vital signs; or electrocardiograms from the pretreatment baseline. Administration of CP-690 550 without a concomitant calcineurin inhibitor resulted in CP-690 550 exposures consistent with previous studies in nontransplant subjects. Additional dose-ranging studies are warranted to evaluate the safety and efficacy of CP-690 550 in renal transplant recipients over longer treatment duration.

Multistage Friend erythroleukemia: independent origin of tumor clones with normal or rearranged p53 cellular oncogenes

The erythroleukemia induced by Friend virus complex in adult mice is a multistage malignancy characterized by the emergence, late in the disease, of tumorigenic cell clones. We have previously shown that a significant proportion of these clones have unique rearrangements in their cellular p53 oncogene. The clonal relationships among Friend tumor cells isolated in the late stages of Friend erythroleukemia were analyzed by examining the unique integration site of Friend murine leukemia virus and the unique rearrangement in their cellular p53 oncogene. The majority of clones isolated from individual mice infected with Friend virus were clonally related as judged by the site of Friend murine leukemia virus integration. However, Southern gel analysis of DNA from individual Friend cell clones indicated that all of the clones with a normal p53 gene from the same mice were clonally related, but were unrelated to the Friend cell lines with a rearranged p53 gene. These results suggest that Friend tumor cells with rearrangements in their p53 gene arise as the result of a unique transformation event, rather than by progression from already existing tumor cells with a normal p53 gene. They also suggest that such rearrangements in the p53 gene confer a strong selective advantage to these cells in vivo.

Prognostic significance of serum p53 protein and p53 antibody in patients with surgical treatment for head and neck squamous cell carcinoma

OBJECTIVES

This study aims at investigating the prognostic values of serum p53 protein and anti-p53 antibody in patients undergoing surgical treatment for head and neck squamous cell carcinoma (HNSCC).

METHODS

Serum p53 protein and anti-p53 antibody concentrations were determined by an enzyme-linked immunosorbent assay (ELISA) in 75 patients with HNSCC and 28 healthy controls. In 28 patients, formalin-fixed tumor tissues were also available for immunohistochemical staining by an anti-p53 DO7 monoclonal antibody. The results were correlated with the clinicopathologic parameters.

RESULTS

The mean preoperative serum concentration of p53 protein in patients with HNSCC was significantly higher than healthy controls (59.45 pg/mL vs 16.4 pg/mL, p =.007). Preoperative serum p53 antibody was present in 23 (31%) patients and was present in one healthy control. Eighteen (62%) tumor tissues showed p53 overexpression by immunohistochemistry. The presence of serum anti-p53 antibody before operation was associated with a significantly higher incidence (65%) of nodal metastasis compared with 27% nodal metastasis in patients with absence of serum anti-p53 antibody (p =.002).

CONCLUSION

Preoperative serum p53 antibody was a significant prognostic factor for nodal metastasis of HNSCC.

Nanostructural characteristics, mechanical properties, and osteoblast response of spark plasma sintered hydroxyapatite

This study aimed to fabricate bulk nanostructured hydroxyapatite (HA) pellets with improved properties using spark plasma sintering (SPS) for orthopedic applications. Spray-dried nanostructured HA (nSD-HA) powders were consolidated using the rapid SPS processing. The SPS processed nSD-HA was characterized using Raman spectroscopy and field emission scanning electron microscopy (FESEM). Mechanical properties of the consolidates were also evaluated through indentation approach. The nanostructures ( approximately 80 nm in grain size) of the starting powders were successfully retained after the SPS processing operated at 950 degrees C with <15 min holding time. The SPS consolidated nSD-HA showed promising mechanical properties, approximately 118 GPa for Young's modulus, and up to 2.22 MPa m(0.5) for fracture toughness. SPS holding time showed minor influence on the phases of the pellets. Furthermore, the spheroidized nanostructured HA retained the HA structure after the SPS consolidation. Preliminary cytotoxicity and cell attachment studies were also carried out using a human osteoblast cell line hFOB 1.19. Enhanced cell attachment and proliferation on the nanostructured pellets were revealed. The presence of the nanostructures accounts mainly for the enhanced mechanical properties and promoted proliferation of the osteoblast cells. This study suggests that the SPS technique is an appropriate process for fabrication of bulk nSD-HA from nanostructured powder.

Parent management training in a Chinese population: application and outcome

OBJECTIVE

To examine the applicability and outcome of parent management training in a group of Chinese children referred for aggressive and defiant behaviors.

METHOD

Twenty-five children (aged 4-10 years) were assigned to a standardized 8 to 12 sessions of parent management training. Trained child and adolescent psychiatric nurses conducted the treatment. Measures taken at pretreatment, posttreatment, and 4-month follow-up period included the Child Behavior Checklist, direct observation of parent-child interactions, and a parent perception inventory.

RESULTS

Significant therapeutic gains occurred in parent-child interactions, externalizing behaviors, and parents' perception of their parenting behaviors. These were maintained at 4-month follow-up. Fifty-two percent of cases improved to a level below clinical cutoffs. Poor parent-child interactions had stronger correlation with externalizing disturbances than internalizing disturbances. The changes in parent-child interactions had low correlation with the changes in the symptom profiles.

CONCLUSIONS

The data provide preliminary evidence for the efficacy of parent management training for Chinese children with conduct problems. The rationale for its success and modifications to improve its cultural sensitivity are discussed.

Transcriptional regulation and structural organization of the human cytosolic phospholipase A(2) gene

Cytokines are established regulators of the arachidonic acid cascade in lung cells. The levels of various arachidonic metabolites distinguish the normal and pathogenic states of the human lung. Arachidonyl-selective cytosolic phospholipase A(2) (cPLA(2)) is ubiquitously present in human lung and is most likely the rate-limiting step in eicosanoid generation. We therefore studied the regulation of this pivotal gene in human lung fibroblasts and epithelial cells by proinflammatory cytokines. We demonstrate a dose- and time-dependent induction of human cPLA(2) mRNA by interleukin-1beta, tumor necrosis factor-alpha, and interferon-gamma as well as the abrogation of this induction by glucocorticoids. Nuclear runoff studies demonstrate that de novo transcription of the cPLA(2) gene is required for cytokine induction. We have characterized the human cPLA(2) gene, which is encoded by 18 exons and spans in excess of 137 kb. Deletion analysis of a 3.4-kb fragment of the human promoter identified two regions responsible for basal expression of the cPLA(2) gene. Conversely, a CA-dinucleotide repeat in the proximal promoter appears to repress overall promoter activity. Understanding the molecular mechanisms associated with cytokine-dependent expression of the cPLA(2) gene should provide further insight into regulating the level of proinflammatory mediators in pulmonary diseases.

Reduced recombination associated with the production of aneuploid sperm in an infertile man: a case report

Studies using gene-linkage analysis have suggested that abnormal recombination during meiosis may lead to the production of aneuploid gametes; however, there is little direct evidence of a link between the two in human males. We analysed spermatocytes in the pachytene stage from a man with extremely high aneuploidy rates in his sperm. Testicular tissue specimens of the infertile man and two vasectomy reversals were processed with immuofluorescent techniques to visualize synaptonemal complex and recombination foci and fluorescent in situ hybridization on spermatocytes and sperm with probes for chromosomes 13, 21, 18, X and Y. We observed no recombination between sex chromosomes in the infertile man, while in two controls, we observed recombination rates of 79.3 and 81.0% between the sex chromosomes. This was associated with a total sex aneuploidy rate of 41.61% in testicular sperm of the infertile man (0.44 and 0.62% in two controls). Recombination on chromosome 21 was reduced in the infertile man, with 10.62% of spermatocytes showing no recombination (0 and 1.67% in two controls), as well as chromosome 13, with 53.98% having < or =1 recombination foci (22.05 and 21.67% in two controls). This was associated with increased aneuploidy for those chromosomes. Chromosome 18 aneuploidy was slightly increased, although there was no apparent decrease in recombination. These results provide the first evidence of both recombination and non-disjunction abnormalities in the same individual. This is also the only reported case of an infertile man who shows no recombination between the sex chromosomes, despite the formation of the sex body.

Asymptomatic left ventricular dysfunction with long-term clozapine treatment for schizophrenia: a multicentre cross-sectional cohort study

Objectives

Patients with schizophrenia treated with clozapine are at risk of acute myocarditis and dilated cardiomyopathy. However, there are no data on the prevalence of subclinical cardiomyopathy or its associations.

Methods

100 consecutive patients with schizophrenia treated with clozapine for >1 year and without a history of cardiac pathology (group 1), 21 controls with a history of schizophrenia treated with non-clozapine antipsychotics for >1 year (group 2) and 20 controls without schizophrenia (group 3) were studied. Comprehensive evaluation by clinical examination, ECG, transthoracic echocardiography including left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) and biochemical profiles were performed.

Results

Patients with schizophrenia were of similar age, but had higher body mass index (BMI), rates of smoking and hyperlipidaemia than controls. Patients with schizophrenia had received clozapine or non-clozapine antipsychotics for a mean duration of 6.8±5.3 and 9.7±6.1 years, respectively. Patients taking clozapine demonstrated globally impaired LVEF (58.3%: group 1 vs 62.2%: group 2 vs 64.8%: group 3, p<0.001) and GLS (−16.7%: group 1 vs −18.6%: group 2 vs −20.2%: group 3, p<0.001). Moreover, LVEF was <50% in 9/100 (9%) patients receiving clozapine and in non-clozapine schizophrenia patients or healthy controls, but this was not statistically significantly different (analysis of covariance, p=0.19). Univariate analysis in patients taking clozapine found that impaired LV was not predicted by high-sensitivity troponin T, but was associated with features of the metabolic syndrome (including increased triglycerides, low high-density lipoprotein cholesterol (HDL-C), high-sensitivity C reactive protein and BMI), elevated neutrophil count, elevated heart rate, smoking and N-terminal probrain natriuretic peptide. In patients taking clozapine, multivariable analysis identified elevated neutrophil count and low HDL-C as the only independent predictors of impaired GLS.

Conclusions

Asymptomatic mild LV impairment is common in patients with schizophrenia receiving long-term clozapine treatment and is associated with neutrophilia and low HDL-C.

Telomerase activity in small cell esophageal carcinoma

Small cell carcinoma of the esophagus is a rare and aggressive malignant tumor. Telomerase activation is common in human cancers. There is a lack of data on telomerase activity in esophageal small cell cancers. The present report studied the role of telomerase activity in esophageal small cell carcinoma. The clinicopathologic data of five patients with small cell carcinoma of the esophagus who underwent primary surgical treatment between 1991 and 2000 were studied. Telomeric repeat amplification protocol assays were used to investigate telomerase activity in these tumors. The proliferative activity (MIB-1) and p53 expression of these tumors were also studied using immunohistochemistry and correlated with the telomerase activity. All five small cell carcinomas showed detectable telomerase activity in the primary tumor. Two out of the five morphologically normal esophageal mucosae adjacent to the primary tumor had detectable telomerase activity. There was no correlation between the p53 expression, tumor stage, survival of patients, and the presence of telomerase activity. High MIB-1 expression in esophageal small cell carcinomas was associated with high telomerase activity. Telomerase activation is common in small cell carcinoma of the esophagus. This fact may find application in anti-telomerase treatment for this aggressive tumor.

Diagnostic investigation of parotid neoplasms: a 16-year experience of freehand fine needle aspiration cytology and ultrasound-guided core needle biopsy

This study aimed to examine the diagnostic yield of fine needle aspiration cytology (FNAC) and ultrasound-guided core needle biopsy (USCB) in the diagnosis of parotid neoplasia. A 16-year retrospective analysis was performed of patients entered into our pathology database with a final diagnosis of parotid neoplasia. FNAC and USCB data were compared to surgical excision where available. One hundred and twenty FNAC, 313 USCB, and 259 surgical specimens were analyzed from 397 patients. Fifty-six percent of FNAC and 4% of USCB were non-diagnostic. One hundred and thirty-two (33%) patients had a final diagnosis made by USCB and did not undergo surgery. Surgery was performed in 257 (65%) patients, 226 (88%) of whom had a preoperative biopsy. Most lesions were benign, but there were 62 parotid and 13 haematological malignancies diagnosed; false-negative results were obtained in three FNAC and two USCB samples. The sensitivity and specificity of FNAC were 70% and 89%, respectively, and for USCB were 93% and 100%, respectively. This study represents the largest series of patients with a parotid neoplasm undergoing USCB for diagnosis. USCB is highly accurate with a low non-diagnostic rate and should be considered an integral part of parotid assessment.

Effect of adult microsurgical varicocelectomy on testicular volume

OBJECTIVES

To re-examine the potential influence of varicocelectomy on testicular volume using scrotal ultrasonography, because it has been reported that total testicular volume (assessed by physical examination) increases after adult varicocele ligation.

METHODS

A retrospective review of the testicular volume and semen parameters of 61 men who underwent microsurgical varicocelectomy between 1996 and 1998 was performed. Ultrasound-derived testicular volumes and total motile sperm counts were compared before varicocelectomy and at a mean of 7.2 months postoperatively.

RESULTS

Bilateral varicocelectomy was performed in 22 men; 39 men underwent a left-sided procedure only. Overall, no significant change was found in the mean total testicular volume after varicocelectomy compared with preoperatively (24.0 versus 23.9 mL, respectively; P = 0.74). Similarly, the testicular volumes did not change significantly after left or bilateral varicocelectomy (P >0.05). Overall, the mean total motile sperm count increased significantly after varicocelectomy (17. 9 to 25.4, P = 0.05).

CONCLUSIONS

This was the first study to examine the effect of adult varicocelectomy on testicular volume using ultrasound-derived measurements of volume. Unlike previous findings, our data suggest that although adult varicocelectomy improves semen quality in most infertile men, it does not result in a significant increase in testicular volume.

The clinicopathologic significance of p53 and p21 expression in the surgical management of lingual squamous cell carcinoma

The aim of the present study was to evaluate the clinicopathologic significance of p53 and p21 expression in lingual squamous cell carcinomas. Immunohistochemical staining was performed with p53 and p21 monoclonal antibodies on surgical specimens from 87 patients who underwent primary surgical treatment for lingual carcinoma between 1976 and 1996. We found positive expression of p53 in 45 (52%) of 87 cases and of p21 in 49 (56%) of 87 cases. There was no correlation of p53 and p21 expression with cancer stage, T stage, nodal metastasis, and tumor grade. Univariate analysis revealed that p21 expression, tumor stage, T stage, and nodal stage were significant prognostic factors for survival. However, only p21 expression and tumor stage were significant independent prognostic factors for survival in a multivariate Cox regression analysis. Overexpression of p21 but not p53 has prognostic value for survival in the surgical treatment of lingual carcinomas. The combination of stage with p21 expression is recommended for evaluation of prognosis and for management planning.

Virology of hepatitis C virus

Advances in molecular biology techniques have allowed the cloning of HCV and the characterization of this virus. This article provides a short summary of our current knowledge on the genomic organization of HCV, the implications of its genetic heterogeneous nature, and the probable replication strategy of this virus.

Evaluation of DNA methylation at imprinted DMRs in the spermatozoa of oligozoospermic men in association with MTHFR C677T genotype

Altered DNA methylation has been previously identified in the spermatozoa of infertile men; however, the origins of these errors are poorly understood. DNA methylation is an epigenetic modification which is thought to play a fundamental role in male germline development. DNA methylation reactions rely on the cellular availability of methyl donors, which are primarily products of folate metabolism, where a key enzyme is methylenetetrahydrofolate reductase (MTHFR). The MTHFR C677T single nucleotide polymorphism (SNP) reduces enzyme activity and may potentially alter DNA methylation processes during germline development. The objective of this study was to determine whether altered DNA methylation in spermatozoa is associated with the MTHFR C677T SNP. DNA methylation was evaluated at the H19, IG-GTL2, and MEST imprinted differentially methylated regions in the spermatozoa of 53 men - 44 oligozoospermic men and nine fertile men with normal sperm parameters via bisulfite sequencing of sperm clones. The 44 infertile men were stratified by severity of oligozoospermia - three normal (>15 million spermatozoa/mL), eight moderate (5-15 million spermatozoa/mL), 23 severe (1-5 million spermatozoa/mL), and 10 very severe (<1 million spermatozoa/mL). MTHFR C677T SNP genotyping was conducted in a subset of 44 peripheral blood samples via restriction fragment length polymorphism. A total of three men - severe oligozoospermic and CT genotype - were found to be altered, which is defined as having ≥50% of their clones altered, where an altered clone was in turn defined as ≥50% of CpGs with incorrect DNA methylation patterns. The incidence of three altered men within the CT subgroup, however, was not significantly higher than the incidence in the CC subgroup. Taken together, altered DNA methylation in spermatozoa was not significantly associated with the MTHFR C677T SNP; however, there was a trend for higher incidence of alterations among severe oligozoospermic infertile men with CT genotypes.

Biosynthesis of rabbit haptoglobin: chemical evidence for a single chain precursor

The primary translation product of the mRNA for rabbit haptoglobin was obtained from a rabbit reticulocyte lysate cell-free system by immunoprecipitation with an antiserum that was directed to the beta chain of haptoglobin. Analysis of the translation product by gel electrophoresis and by protein sequencing analysis identified a single polypeptide of Mr 41 000. Sequence analysis established a signal region of 18 residues that was immediately followed by the alpha chain sequence. These results give strong evidence that haptoglobin is initially synthesized as a single chain composed of a signal peptide followed by alpha and beta chain regions, respectively.

A comparative study of cervical cytology, colposcopy and PCR for HPV in female sex workers in Singapore

This study examined the prevalence of human papillomavirus (HPV) infection in a cohort of female sex workers in Singapore. HPV infection was diagnosed by clinical examination, Papanicolaou (Pap) smears, histology and polymerase chain reaction (PCR). One hundred and eighty-seven female sex workers who came for their routine medical screening were enrolled into the study. PCR was positive for HPV in 27 (14.4%), 20 of these had a single HPV type detected, while 7 had multiple types of HPV detected. The most common HPV types identified were types 16, 58 and 18. In conclusion, HPV infection is moderately prevalent among sex workers as tested by PCR, but routine screening with Pap smears does not appear to be a sensitive method of diagnosis for HPV infection.

Molecular diagnosis of genital HPV DNA types by polymerase chain reaction and sensitivity-standardized filter in situ hybridization in randomly sampled cohorts of Singapore women

Infection of the cervix uteri with various types of human papillomaviruses is generally considered a necessary factor in the etiology of cancer of the cervix uteri. In many human populations throughout the world, approximately 90% of cervical carcinomas are found to harbour HPV genomes, as judged by Southern blot hybridization, while only a few percent of the cervical smears of asymptomatic individuals contain viral DNA, as assessed by filter in situ hybridization. To obtain corresponding epidemiological data from Singapore, we analysed two groups of 740 and 130 individuals by filter in situ hybridization, and found 4.1% and 6.9% of them to be HPV positive, with HPV 16 and HPV 31 being the predominant types. In consideration of the limitations of filter in situ hybridization, namely low sensitivity and a tendency to suggest false positives due to contaminants, including blood, we analysed the cervical smears of two further groups of 52 and 50 individuals by the polymerase chain reaction for infection by HPV 16 and HPV 18 respectively. With this test, 61% and 14% of the cervical smears proved to be HPV 16 and HPV 18 DNA positive respectively. We conclude that in Singapore, if not worldwide, the majority of the population the population is infected by genital HPV types, suggesting that factors other than HPV infection are ultimately rate-limiting in cervical carcinogenesis.