Human papillomavirus in false negative archival cervical smears: implications for screening for cervical cancer.

AIM--To assess the value of detecting human papillomavirus (HPV) DNA in false negative archival cervical smears in population based screening programmes for cervical cancer. METHODS--Cytomorphologically classified false negative archival Pap smears (n = 27) taken from 18 women up to six years before cervical cancer was diagnosed were blindly mixed with 89 smears from hospital patients with a variety of gynaecological complaints and tested for HPV by the polymerase chain reaction (PCR). Corresponding cervical cancer biopsy specimens were also available for HPV analysis. Neither the examining cytopathologist nor the molecular biologist was aware of the study design. RESULTS--HPV DNA was detected in the smears of 16 patients with cervical cancer missed previously by cytology. HPV 16 and 18 were found predominantly in those smears taken up to six years before the diagnosis of cervical cancer. The smears of the two remaining patients were reclassified as inadequate for cytology or contained no suitable DNA for PCR. In 15 patients the same HPV type could be found in the smears and the cervical cancer biopsy specimens. CONCLUSIONS--The results indicate that high risk HPV types can be detected in archival smears classified as false negative on cytology and that cytological screening errors may be reduced if combined with PCR testing for HPV.     

Significance of PBMC response of rheumatic fever patients and control individuals to immunodominant streptococcal M5 protein epitopes

β-hemolytic streptococcal infection in developing countries still causes thousands of cases of Rheumatic Fever (RF). Molecular mimicry between streptococcal M protein (strep M) and heart components has been proposed as the triggering factor leading to autoimmunity in individuals with genetic susceptibility, which is linked to different HLA-DR alleles in different populations. In our hands, RF was significantly associated to HLA-DR7/53. Previous work in our lab has shown that heart-infiltrating T cells that simultaneously recognize strep M and heart proteins. Further, such T cells predominantly recognized the 81-103 strep M5 epitope. In this work, we analysed the proliferative response of peripheral blood mononuclear cells of 99 RF patients and 40 normal controls. Eighty-nine of the RF patients were HLA-typed. As among heart-infiltrating T cells, the 81-103 strep M5 protein epitope is the most frequently recognized epitope among RF PBMC (35.4%), against a 7.5% frequency of proliferation among normal controls (p=0.0018, chi square). However, the 81-103 epitope was as frequently recognized by HLA-DR7,53 positive as by negative individuals (45.2% vs 54.8%, respectively). Taken together, the results suggest that the 81-103 strep M5 epitope may be the immunodominant epitope, “promiscuously” recognized by T cells in a genetically diverse population. The demonstration that molecular mimicry is targeted to a discrete immunodominant “promiscuous” epitope in strep M5 may allow the development of a safe anti-streptococcal synthetic vaccine devoid of such epitopes.     

Recurrence of bronchioloalveolar carcinoma in donor lung after lung transplantation: microsatellite analysis demonstrates a recipient origin

Bronchioloalveolar carcinoma is a distinctive subtype of pulmonary adenocarcinoma, without effective therapy, although there have recently been some attempts to use lung transplantation. However, a high post-transplantation local recurrence rate is described with some controversy regarding the possible involved mechanisms, the main possibilities being the lymphatic spread and aerosolization. Presented herein is a case of a bilateral lung transplantation for a bilateral and pneumonic form of non-mucinous bronchioloalveolar carcinoma in a 43-year-old woman. The histological analysis of mediastinal lymph nodes during surgery did not show neoplastic cells. Thirty-five months after transplantation several nodular opacities in donor lungs were detected. Three pulmonary wedge resections were performed showing a non-mucinous bronchioloalveolar carcinoma with the same histological characteristics as the primary. Again, the mediastinal lymph nodes were tumor free. A complete microsatellites molecular analysis was performed to compare the primary and recurrent carcinoma using capillary electrophoresis, showing that the recurrent tumor was generated in a recipient cellular clone. The absence of lymph node metastasis and the molecular evidence of the recipient origin of the neoplasm supports the contamination of the new lungs at the time of implantation as being the reason for the high incidence of recurrence after lung transplantation in this kind of disease.     

HLA allele and haplotype frequencies in Algerians : Relatedness to Spaniards and Basques

The powerful genetic polymorphism of the HLA system has been used to identify individuals and populations. Ethnic groups may be characterized by specific HLA allele frequencies and particular extended HLA haplotypes; also, genetic relationships among these groups may be deduced. In the present study, serology and DNA typing were used to detect HLA-A, -B, -C, -DR, and -DQ alleles in each individual and to calculae characteristic haplotypes in Algerians. These results were compared to those previously obtained in other populations, particularly northern Mediterraneans; genetic distances and their respective dendrograms place Basques and Spaniards closer to Algerians than to other Europeans. Also, characteristic Basque and/or Spanish haplotypes are found in Algerians; i.e., A30-B18-Cw3-DR3-DQ2 and Al-B57-Ctv7-DR7-DQ2. This supports the evidence that the Algerian population, mainly its paleo-North African component (Berbers), has a common descent with Basques and Spaniards, probably reflecting a preneolithic relationship between Iberians and paleo-North Africans.     

Regulation of secondary lymphoid organ development by the nuclear factor-κB signal transduction pathway

Summary: In primary lymphoid organs, such as thymus and bone marrow, B and T lymphocytes differentiate from lymphoid stem cells into mature albeit naïve effector cells. In contrast, secondary lymphoid organs, such as the spleen, lymph nodes, and Peyer's patches (PPs), provide an environment that enable lymphocytes to interact with each other, with accessory cells, and with antigens, resulting in the initiation of antigen‐specific primary immune responses. Recently, the analysis of gene‐knockout mice has shed light on the signaling pathways, cellular requirements, and molecular mechanisms involved in secondary lymphoid organ development. In particular, signals that converge on the nuclear factor‐κB (NF‐κB) pathway have been demonstrated to play an important role in both early developmental steps as well as maintenance of secondary lymphoid organ structures. Analysis of the histopathological changes in secondary lymphoid tissues of mice lacking individual Rel/NF‐κB family members, upstream kinases, and receptors strongly indicates that activation of the recently described alternative NF‐κB pathway by membrane‐bound lymphotoxin, via p52–RelB heterodimers, plays a major role during initiation steps of secondary lymphoid organ development. Induction of the classical p50–RelA NF‐κB activity, as exemplified by tumor necrosis factor receptor signaling, clearly also contributes, but seems to be involved primarily in later developmental step, such as the proper cellular and structural organization of B‐cell follicles.     

Genome of the European elk papillomavirus (EEPV)

The genome of the European elk papillomavirus (EEPV) was found to be 8,095 base pairs (bp) long and its genetic organization was similar to that of other papillomaviruses. Ten open reading frames (ORFs), designated E1-E7 and L1-L3, were identified in the genome, all located on one strand. The presence of the L3 ORF is rare among the papillomaviruses and to date has only been identified in the genomes of EEPV, the deer papillomavirus (DPV) and the Cottontail papillomavirus (CRPV). The ORF is well conserved beteeen DPV and EEPV with regard to both length and sequence. Potential promoter regions were identified at the 5-end of the E6 ORF, at the 3-end of the E1 ORF and downstream of the L1 ORF. Furthermore, two potential polyadenylation signals were found, one located in the long control region (LCR), downstream of the L1 ORF, and another preceding the L2 ORF. The EEVP genome is closely related to the genome of the DPV, the most highly conserved regions being ORFs E1 (70%), E5 (69%), and L1 (74%).     

Relationship between chamber mechanical properties and mean pressure-mean flow diagram of the left ventricle

We undertook a theoretical analysis of the source resistance of the left ventricle represented in a mean pressure-mean flow diagram, using the chamber properties established in terms of the pressure-volume relationship. This analysis showed that pairs of points should lie above the linear function proposed by Elzinga and Westerhof. A third-order polynomial function would theoretically explain better than a linear relation or a parabolic fit the curved shape of experimentally obtained relationships. The analysis resolves the discrepancy between Elzinga and Westerhof's theoretical concept of linear source resistance and the actual nonlinear relationship.     

The induction of class I HLA by interferon-α is independent of the cell cycle,but the expression is enhanced by a G1/S block

The induction of class I HLA expression by interferon-α (IFN-α) was studied in lymphoid cells arrested or traversing different stages of the cell cycle. Exponential cultures of MOLT-4 cells and the MOLT-4 cell variant YHHH were treated with the cell cycle inhibitors aphidicolin and colcemid to obtain cell populations arrested in G₁/S and G₂/M, respectively, and also cells traversing from S to M and vice versa. Cytofluorimetry with the monoclonal antibody YTH/76.3 (which specifically detects those class I molecules which are most susceptible to IFN-α induction) was used to quantitate the class I HLA response to IFN-α. The results showed that the response to IFN-α is not restricted to a given stage of the cell cycle. These studies also revealed that when the cells were arrested at G₁/S, the absolute level of class I HLA expression was enhanced 2–3-fold, both in the presence or absence of either IFN-α or IFN-γ. Therefore, even when absolute levels changed, the ratio of IFN-induced expression to basal expression remained constant at all cell cycle stages. The level of expression of another surface antigen (the CD1 antigen HTA-1) was not affected by the G₁/S block. The results were confirmed by dot blot hybridization of poly (A)⁺ RNA using cDNA-specific probes. These findings suggest that the effect of IFN-α is continuous throughout the cell cycle but that a G₁-dependent event determines the extent of class I HLA expression, and leads to a synergistic superinduction by IFN in G₁/S-arrested cells.     

Imaging of the varicella zoster virion in the viral highways: comparison with herpes simplex viruses 1 and 2, cytomegalovirus,pseudorabies virus,and human herpes viruses 6 and 7

Imaging by scanning electron microscopy (SEM) can provide insight into viral egress. At a low magnification level, varicella zoster virions (VZV) emerge from an infected cell surface in a distinctive pattern previously described as "viral highways." Viral highways consist of thousands of particles arranged in linear pathways across the syncytial surface. This egress pattern has not been described with other herpesviruses, but a systematic analysis has not been performed. Therefore, the characteristic arrangement of VZV egress was compared with that of six other members of the herpes virus family, including herpes simplex virus (HSV) types 1 and 2, human cytomegalovirus (CMV), pseudorabies virus (PRV), and human herpesvirus types 6 and 7 (HHV-6 and HHV-7). Only VZV-infected cells exhibited viral highways. Subsequent SEM examination of VZ virions at an ultra high-resolution revealed that more than 70% were aberrant. Further imaging of the other herpesviruses demonstrated that VZV structure was more closely related to PRV than HSV-1 or HSV-2. Finally, it is noted that the individual members of the herpesvirus family have distinguishable SEM profiles.