Chromosome loss is responsible for segregation at theHPRT locus in Chinese hamster cell hybrids

The phenomenon of segregation of gene expression has been examined in intraspecific somatic cell hybrids. Specifically, segregation at the hypoxanthine guanine phosphoribosyltransferase (HPRT)locus has been studied in hybrids of Chinese hamster cell lines. The role of chromosome segregation, or other chromosomal events has been assessed by detailed comparison of karyotypes in the 6-thioguanine resistant segregants with those of the parental hybrid lines. The results clearly demonstrate that loss of an entire X chromosome is the primary event responsible for segregation at the HPRTlocus, while deletion of a portion of the short arm of an X chromosome was also a frequent event. The results provide the first direct evidence for the assignment of the HPRTlocus to the X chromosome in Chinese hamster, and in fact allow mapping of this locus to the distal region of the short arm. Analysis of chromosome number distributions in the hybrids and segregants suggests that in selecting chromosomal segregants one may also select for hybrid lines with reduced chromosome stability.     

Seroprevalence of human herpesvirus-8 in blood donors from different geographical regions of Argentina, Brazil, and Chile

Human herpesvirus-8 (HHV-8) causes Kaposi's sarcoma (KS) and lymphoproliferative disorders in both HIV-infected and uninfected patients. HHV-8 has a worldwide occurrence but infection rates vary according to a combination of geographic and behavioral risks. The main transmission route seems to be sexual, nevertheless, nasal secretions, saliva, blood, and organ graft have been proposed. HHV-8 was postulated as a new infectious agent for screening in blood donors. The aim of this study was to evaluate the prevalence of antibodies against HHV-8 antigens in blood donors of South America. Serum samples from 2,470 blood donors from Argentina, Brazil, and Chile corresponding to five geographic regions were studied by indirect immunofluorescence assay (IFA). Seroprevalence rate was 3.7% (92/2,470; 95% CI 2.9-4.5) in the entire blood donor population distributed as follows: Argentina, 4.0% (Buenos Aires city, 4.3%; Bahia Blanca, 2.4%; and Córdoba, 4.0%), Campinas (Brazil), 2.8%; and Santiago de Chile, 3.0%. There was no difference (P>0.05) between men and women or age related, except in Brazil where positive cases were 30-49-year-old males. The present study, which includes different geographical areas of multiple countries from South America, has not been done before. The results show similar prevalence rates among the studied zones corresponding to low-prevalence regions. South America is a large sub-continent with a wide spectrum of population and geographical characteristics, thus, more HHV-8 prevalence studies should be necessary to establish possible regional differences.     

Multilaboratory Evaluation of a Viability Assay for Measurement of Opsonophagocytic Antibodies Specific to the Capsular Polysaccharides of Streptococcus pneumoniae

Opsonophagocytosis is a correlate of protection that measures the functional activity of vaccine-induced antibodies. A standardized opsonophagocytosis assay (OPA) should be used as part of the evaluation of current and future pneumococcal (Pnc) polysaccharide (Ps)-based vaccines. We enrolled five laboratories to evaluate a previously standardized viability OPA. Each laboratory was provided with a detailed OPA protocol, seven target Pnc strains (serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F), two quality control sera and 12 paired sera (blinded) from adult donors who received one dose of the 23-valent Pnc Ps vaccine. Laboratories sent their results to the Centers for Disease Control and Prevention for analysis. Sera were tested in duplicate (single run), and the results were averaged to yield a single OPA titer (≥50% killing) for each serum sample. The percentage of sera within one or two dilutions of the calculated median OPA titer was determined for each laboratory and for each serotype. In general, laboratories were capable of detecting OPA titers within one or two dilutions of the median for at least 75 and 88%, respectively, of the sera tested. The level of agreement with the median OPA titers varied depending on the participating laboratory (overall agreement = 0.8 [99% confidence interval = 0.75 to 0.85]). All OPA median titers reported for quality control sera were within one dilution of the expected titer. We conclude that this OPA can be done in multiple laboratories with a high degree of interlaboratory reproducibility.     

Relief of cough and nasal symptoms associated with allergic rhinitis by mometasone furoate nasal spray.

BACKGROUND: Cough commonly occurs as a symptom of seasonal allergic rhinitis (SAR), an inflammatory condition of the nasal mucous membranes that results in rhinorrhea, nasal stuffiness/congestion, nasal itching, and sneezing. Mometasone furoate nasal spray (MFNS, Nasonex, Schering, Kenilworth, NJ), an anti-inflammatory nasal corticosteroid, has been shown to be safe and effective in reducing the nasal inflammation of SAR. OBJECTIVE: To examine the effectiveness of MFNS in relieving SAR-associated cough, in addition to nasal symptoms. METHODS: This was a multicenter, randomized, double-blind study. Patients 12 years of age or older with > or = 1-year history of SAR symptoms, positive skin test to a prevailing seasonal allergen, moderate nasal symptoms, and moderate cough were treated for 14 days with MFNS 200 microg daily (n = 122) or placebo (n = 123). RESULTS: The group treated with MFNS showed significant improvement in the daytime cough severity score at endpoint compared with placebo (P = 0.049). Improvement in the nighttime cough severity score showed a trend in favor of MFNS treatment. Treatment with MFNS significantly improved total nasal symptoms in both the daytime and nighttime compared with placebo at endpoint (P < or = 0.017). Overall daytime symptom scores (cough + total nasal) improved significantly compared with placebo at endpoint (P = 0.005). Overall nighttime symptom scores improved significantly compared with placebo at endpoint (P = 0.028). Treatments were well tolerated, with no significant differences in the incidence of adverse events. CONCLUSIONS: MFNS is effective and well tolerated in the treatment of daytime cough associated with SAR.     

Frequency of delta F508 mutation in Venezuelan patients with cystic fibrosis

Cystic Fibrosis (CF) is the most common and severe autosomal recessive disease in Caucasian populations, with an incidence of 1 in 2500 live births. It is characterized by a generalized disturbance in exocrine glands and it is caused by over one thousand mutations at the cystic fibrosis conductance regulator gene (CFTR) mapped at 7q31. AF508 is the most frequent mutation worldwide and it consists in a deletion of the codon that encodes fenilalanine at the 508 protein's position. The aim of this study was to determine the frequency of the delta F508 mutation in Venezuelan patients with CF using the Polymerase Chain Reaction (PCR). We studied thirty patients of twenty eight families who were diagnosed with CF based on their clinical features and sweat chloride level > 60 mEq/l in two determinations. Detection of the mutation was performed from the amplification of a 98 pair of bases (pb) CF gene segment which contains the codon that encodes fenilalanine in the 508 position by PCR. This PCR product is absent in those who have the mutation. The delta F508 allelic frequency was 26.79%, distributed in six homozygous and seven compound heterozygote delta F508/X. The reminder mutations (no delta F508) represent 73.21%. The delta F508 frequency in our sample is less than the reported in European countries. On the other hand, a delta F508 frequency highly heterogeneous has been observed in Latin-American countries. This variation results from mixed populations with a different genetic background influenced by external migration and CF molecular alterations, which exists in the analyzed populations. In this study, the delta F508 mutation comes mainly from grandparents (79.41%) who were born in Mediterranean countries and Colombia, while the no delta F508 mutations come from grandparents who were born in Venezuela (79.27%) and Colombia (17.07%).     

The hypoxia-regulated transcription factor DEC1 (Stra13, SHARP-2) and its expression in human tissues and tumours

DEC1, also known as SHARP-2 or Stra13, is an important molecule in embryonic differentiation and has recently been identified to be strongly inducible by hypoxia. Its distribution in normal human tissues and most tumour types is unknown. In the present study, a polyclonal antiserum to a 10-amino acid peptide from DEC1 has been raised. Using this antiserum, DEC1 was shown to be widely expressed in most normal human tissues, but usually only in a proportion of cells and typically with a nuclear localization. In tumours, expression was either augmented (the commonest pattern) or occasionally decreased. Similarly, in most normal tissues, low or absent expression was observed in endothelial cells, whereas in many tumour samples endothelium was usually strongly positive. In tumours, there was a striking pattern of staining seen in connection with areas of necrosis, with absence of DEC1 expression within a zone of morphologically viable cells immediately adjacent to the necrotic zone. This suggests that while DEC1 may be up-regulated by hypoxia in cancer, in more extreme hypoxia it may have a role in cell death. Its interrelationship with other hypoxically regulated molecules, such as the hypoxia-inducible factors or carbonic anhydrase IX, and differentiation of tumours now requires further investigation.     

Primary myeloid sarcoma of the testicle with t(15;17)

The first case of acute promyelocytic leukemia presenting as a solitary testicular mass (myeloid sarcoma) that relapsed in the contralateral testicle is described. The neoplastic cells strongly expressed chloroacetate esterase, myeloperoxidase, CD33, CD43, and weakly, CD117. The presence of many azurophil granules and Auer rods was detected by electron microscopy. Translocation (15;17)(q22;q21.1) was revealed by cytogenetics and was verified by fluorescence in situ hybridization. Contralateral testicle is a favorite site for recurrence in a subset of testicular myeloid sarcomas. Subclassification of all cases of myeloid sarcoma ought to be attempted.     

Proliferative activity in benign and neoplastic prostatic epithelium

The increasing availability of means for the early detection of prostatic cancer has brought under scrutiny the criteria used for prognosis and emphasized our limitations in understanding what determines the rate of progression in these cancers. The rate of cancer cell proliferation has been under intense investigation, which, however, has yielded conflicting results. In this study we evaluated the proliferative activity of benign and neoplastic prostatic epithelium, using various existing methodologies. We first analysed the variability introduced by the methodological approach and then attempted to demonstrate whether determination of the proliferative capacity had any clinical consequence that complemented the histological grading. Tissue samples from patients, 88 with cancer and 46 with benign prostatic pathology, were studied using in vitro bromodeoxyuridine (BrdU) incorporation as well as Ki67 and the proliferating cell nuclear antigen (PCNA) to estimate the proliferative activity. Increased proliferation was found consistently in inflammation and metaplasia, but not in hyperplasia. In contrast, cancers showed marked variability. Although average proliferation indices increased with grade, there was a wide scatter of values. Correlation was stronger with stage, but also depended on the methodology. Bromodeoxyuridine indices over 10 per mille had a positive predictive value of 79 per cent for cancers extending beyond the prostatic capsule and may prove particularly helpful for evaluating patients with grade 7 cancer. This observation is significant, since grade 7 cancers are the most frequent and the least predictable.     

Analysis of the targeting of the hypermutational machinery and the impact of subsequent selection on the distribution of nucleotide changes in human V rearrangements

Summary: B cells are unique in that they generate and tolerate a high rate of mutations in their antigen receptor genes and employ these mutations as a basis of avidity maturation. The precise role of the mutational machinery versus subsequent selection in determining the frequency and distribution of mutations has not been fully analyzed. To address these issues, the influence of the intrinsic mutational machinery and subsequent selection on the frequency and distribution of mutations in the expressed human immunoglobulin repertoire was analyzed. Analysis of non-productively rearranged v_H genes from individual human B cells provided an opportunity to examine the immediate impact of somatic hypermtitation without superimposed selective influences. Comparison with the frequency and distribution of mutations in the productively rearranged human V_H genes permitted an estimate of the influences of subsequent selection.