Lack of association between cytomegalovirus infection of heart and rejection-like inflammation.

Serial myocardial biopsy specimens, taken up to the time of serological evidence of primary cytomegalovirus (CMV) infection in 22 heart transplant patients, were examined and compared with those taken over similar times after transplantation in 21 patients who did not develop CMV infection. None of these 43 patients had serological evidence of CMV infection before their heart transplantation. There was no evidence of an increased cellular infiltrate in the myocardium at the time of the active CMV infection, even though the donor heart is the likeliest source of infection, nor was there any change in myocyte, interstitial cell, or vascular endothelial cell nuclei to identify active CMV infection.     

Cytogenetics of human brain tumors

The most frequent cytogenetic alterations in primary brain tumors are losses of chromosomes or chromosomal regions and the presence of double minute chromosomes (dmins). The regions which are lost and the genes which are amplified are distinctive for individual tumor types. Most malignant gliomas contain gains of chromosome 7 and losses of chromosome 10; losses of chromosome 22, 9p, and the sex chromosomes occur in subgroups of cases. The gene most frequently amplified in tumors with dmins is the epidermal growth factor receptor gene. Medulloblastomas have losses of 17p and most cases with dmins have c-myc gene amplification. Meningiomas have losses or deletions of chromosome 22. Identification of these specific cytogenetic abnormalities in human brain tumors has provided the framework for identifying genes which are amplified in them and has identified chromosomal regions likely to contain tumor suppressor genes, the loss or inactivation of which is important in the development of these tumors.     

Cytogenetic studies in twenty human brain tumors: Association of no. 22 chromosome abnormalities with tumors of the brain

The chromosomes were analyzed in cells from twenty cases of primary brain tumors cultured for short periods. There were nine cases with chromosome abnormalities; eight of these showed an abnormality involving a No. 22 chromosome. Three cases each of pituitary adenoma and craniopharyngioma showed no chromosome abnormalities. In five of the seven cases of meningioma studied, hypodiploid clones caused by the loss of 1 to 4 chromosomes were observed. Detailed analysis of the missing chromosomes, revealed the loss of a No. 22 chromosome, an aberration specific for meningioma. Two astrocytomas and a case of oligoden-droblastoma also showed an abnormal No. 22 chromosome. The possible significance of the association of No. 22 chromosome abnormalities with tumors of the brain is discussed in the light of findings, obtained to-date, in the field of tumor cytogenetics.     

On the association of human beta 2 microglobulin with cell culture-grown human cytomegalovirus (HCMV).

We studied the production of human beta 2 microglobulin (beta 2m) in mock-infected or human cytomegalovirus (HCMV) infected human embryonic lung fibroblasts (HEL) and the association of human beta 2m with HCMV virions. Titration of beta 2m by two-step sandwich enzyme immunoassay revealed that HEL released considerable amounts of human beta 2m into the culture medium and that the production of beta 2m was significantly enhanced by HCMV infection. The concentration of human beta 2m in the culture medium of HCMV-infected HEL reached 500 to 600 ng/ml, which corresponded to 7- to 12-fold of levels found in healthy adult urine. Immunoprecipitation assays showed that HEL-grown HCMV bound a significant amount of endogenous beta 2m, but the viruses were efficiently neutralized by either human hyperimmune anti-HCMV globulin or anti-HCMV monoclonal antibody even when treated with a large amount of human beta 2m or with dialysed urine. Thus it seems unlikely that the binding of beta 2m by HCMV is involved in masking the viral antigenic site necessary for neutralization.     

Unexpected immunoreactivities of intermediate filament antibodies in human brain and brain tumors.

Immunoreactivities of 35 different monoclonal antibodies (MAbs) that detect intermediate filaments were studied systematically on serial cryostat sections of 14 well-defined human gliomas (five astrocytomas, three oligodendrogliomas, six glioblastomas) and on normal brain. Glial fibrillary acidic protein (GFAP), vimentin, desmin, neurofilaments, and broad-specificity keratin MAbs, as well as MAbs that recognize several or only single keratin polypeptides, were used. Unexpected reactivities were surprisingly frequent. As these may lead to diagnostic confusion and misinterpretation on this material, the authors investigated these phenomena more thoroughly. Four major sources of artifactual staining were found: 1) positive staining attributable to the rabbit gamma G immunoglobulins used in the alkaline phosphatase anti-alkaline phosphatase technique; 2) certain desmin and keratin MAbs cross-reacted with astrocytic glia and with other brain-specific epitopes; 3) technical difficulties; 4) some MAbs directed against neurofilaments and keratins showed unexpected reactivities only on individual anaplastic gliomas. The implications of these findings for intermediate filament typing of neuropathologic material are discussed.     

Infection of human amnion cells with cytomegalovirus.

Human cytomegalovirus (CMV), known to replicate in vitro in human fibroblastic cells, was found to replicate in epithelial human amnion (HA) cells. Large syncytia formed in these cells after infection with CMV; inclusion bodies were observed in the nuclei, and CMV antigens were demonstrated in both the cytoplasm and the nucleus by indirect immunofluorescence techniques. The synthesis of virus DNA was also detected, and the production of infectious virus was followed. The titers were lower (from 10(4) to 6 X 10(5) using different isolates of CMV) than those obtained in human embryo fibroblast (HEF) cells, and the replication cycle was slower in HA than in HEF cells.     

Gene expression of apolipoprotein E in human brain tumors.

Samples of normal brain, two meningiomas, one medulloblastoma and seven astrocytomas were analyzed along with two glioma lines to determine the genic expression of apolipoprotein E, which in addition to its major function in lipid metabolism has been postulated to be a marker for astrocytomas. Messenger ribonucleic acid encoding apolipoprotein E was found to be expressed in significant amounts in all of the brain tumor specimens and in the normal brain, but in only one of the two glioma lines. Although the role of apolipoprotein-E in the brain and in brain tumor growth remains undefined, it is clear that this gene is expressed in substantial amounts in a variety of brain tumors and is not specific for astrocytomas.     

Telomeric association in two human renal tumors

Telomeric association of chromosomes was detected in two of 20 human renal tumors, namely, in a papillary renal cell carcinoma and a renal oncocytoma. The smaller chromosomes were preferentially involved in this phenomenon.     

Induction of brain tumors in hamsters with BK virus, a human papovavirus.

The oncogenicity of BK virus for the central nervous system was studied in newborn hamsters. The virus was weakly oncogenic after intracerebral inoculation. Two of 45 hamsters treated with antithymocyte serum developed tumors whereas no untreated hamsters developed tumors. Both tumors were choroid plexus papillomas by histologic and electron microscopic examination. Cells cultured from one tumor had growth characteristics of transformed cells and had intranuclear T antigen; but infectious virus could not be rescued. Cultured tumor cells were weakly oncogenic for hamsters, but theoncogenicity of these cells was enhanced when the recipient animals were treated with antithymocyte serum. The possible role of host immune response as a basis for the weak oncogenicity of BK virus is discussed.     

Fetal microchimerism in human brain tumors

Sex differences in cancer incidence and survival, including central nervous system tumors, are well documented. Multiple mechanisms contribute to sex differences in health and disease. Recently, the presence of fetal‐in‐maternal microchimeric cells has been shown to have prognostic significance in breast and colorectal cancers. The frequency and potential role of these cells has not been investigated in brain tumors. We therefore selected two common primary adult brain tumors for this purpose: meningioma, which is sex hormone responsive and has a higher incidence in women, and glioblastoma, which is sex hormone independent and occurs more commonly in men. Quantitative PCR was used to detect the presence of male DNA in tumor samples from women with a positive history of male pregnancy and a diagnosis of either glioblastoma or meningioma. Fluorescence in situ hybridization for the X and Y chromosomes was used to verify the existence of intact male cells within tumor tissue. Fetal microchimerism was found in approximately 80% of glioblastoma cases and 50% of meningioma cases. No correlations were identified between the presence of microchimerism and commonly used clinical or molecular diagnostic features of disease. The impact of fetal microchimeric cells should be evaluated prospectively.     

Lack of association of HLA class II alleles with peanut allergy.

BACKGROUND: Peanut allergy is a common and severe phenotype of food allergy with a strong genetic component; HLA class II polymorphisms are attractive candidate genes for this disorder. Objective: To determine possible genotypic associations of HLA class II with peanut allergy and attempt replication of previously reported associations. METHODS: Sibling pairs discordant for peanut allergy were genotyped (low resolution) by polymerase chain reaction-based methods to 7 DQ and 18 DR allele groups. A chi2 analysis was undertaken against sibling controls with statistical adjustment for multiple analyses. RESULTS: Seventy-three children with confirmed peanut allergy (mean age, 6.5 years; male, 72%; asthma, 58%; atopic dermatitis, 62%; allergic rhinitis, 67%; other food allergies, 41%) and 75 of their siblings who eat peanut (mean age, 8 years; male, 52%; asthma, 12%; atopic dermatitis, 22%; allergic rhinitis, 37%; other food allergy, 7%) were genotyped. Distribution of DQ7 (29% of children with peanut allergy vs 47% sibling controls) was statistically significantly different (P = .04) before statistical correction for multiple comparisons was made by multiplying them by the number of alleles tested (and not statistically significant after correction; P = .30). Distribution of DR11 was nearly statistically significant without statistical adjustment (26% with peanut allergy vs 41% of sibling controls; P = .07; corrected P = 1.3). Alleles that were previously reported to have a weak association with peanut allergy (DRB1 *03, *08; DQB1 *0302, *04) were not verified in this cohort (unadjusted P > .44). CONCLUSIONS: We could not establish an association between the HLA class II alleles evaluated in this cohort of sibling pairs discordant for peanut allergy.     

Lack of transmission to polymorphonuclear leukocytes and human umbilical vein endothelial cells as a marker of attenuation of human cytomegalovirus.

The development of a human cytomegalovirus (HCMV) vaccine for the prevention of perinatal disease is urgently needed. However, markers of HCMV attenuation are not defined at present. An in vitro model for the study of interactions of HCMV-infected human fibroblasts and peripheral blood polymorphonuclear leukocytes showed that (1) known laboratory-adapted HCMV strains as well as cell culture-adapted HCMV isolates were not transmitted to polymorphonuclear leukocytes; (2) each of the 80 HCMV recent isolates was consistently transmitted to polymorphonuclear leukocytes as both infectious virus and viral components (nucleic acid and proteins); and (3) all 15 polymorphonuclear leukocyte-tropic strains tested thus far were also endothelial cell-tropic. The in vitro transmissibility to polymorphonuclear leukocytes (and endothelial cells) is proposed as a surrogate marker of pathogenicity of HCMV strains. It seems reasonable to assume that a HCMV strain candidate for a vaccine be verified as deprived of the transfer property to polymorphonuclear leukocytes (and endothelial cells) before involvement in clinical trials assessing safety and immunogenicity.     

Lack of association between C-PiB and longitudinal brain atrophy in non-demented older individuals

Amyloid-β plaques (Aβ) are a hallmark of Alzheimer's disease (AD), begin deposition decades before the incipient disease, and are thought to be associated with neuronal loss, brain atrophy and cognitive impairment. We examine associations between ¹¹C-PiB-PET measurement of Aβ burden and brain volume changes in the preceding years in 57 non-demented individuals (age 64–86; M = 78.7). Participants were prospectively followed through the Baltimore Longitudinal Study of Aging, with up to 10 consecutive MRI scans (M = 8.1) and an ¹¹C-PiB scan approximately 10 years after the initial MRI. Linear mixed effects models were used to determine whether mean cortical ¹¹C-PiB distribution volume ratios, estimated by fitting a reference tissue model to the measured time activity curves, were associated with longitudinal regional brain volume changes of the whole brain, ventricular CSF, frontal, temporal, parietal, and occipital white and gray matter, the hippocampus, orbito-frontal cortex, and the precuneus. Despite significant longitudinal declines in the volumes of all investigated regions (p < 0.05), no associations were detected between current Aβ burden and regional brain volume decline trajectories in the preceding years, nor did the regional volume trajectories differ between those with highest and lowest Aβ burden. Consistent with a threshold model of disease, our findings suggest that Aβ load does not seem to affect brain volume changes in individuals without dementia.     

Defective virions of human cytomegalovirus.

Passage of human cytomegalovirus at high multiplicity of infection generated defective virus particles which banded in CsCI at a lower buoyant density than standard virus. The DNA from defective virions banded at a lower buoyant density in CsCl than standard DNA and sedimented in sucrose gradients similar to standard DNA. Contour length measurements of DNA from defective virions revealed various classes of DNAs ranging in molecular weight from 40 to 120 x 10⁶; this was in contrast to standard DNA with a molecular weight of 150 x 10⁶.     

Chromosome studies in two human brain tumors

The cytogenetic findings based on G- and C-banding in two human brain tumors (a meningioma and an astrocytoma) are reported. Both tumors were characterized by hypodiploid modal numbers (45 and 40 chromosomes, respectively), chromosome 22 abnormalities, and the presence of several markers. This observation supports the hypothesis of the association of No. 22 chromosome abnormalities with tumors of the brain.     

Quantitation of human cytomegalovirus genomes in the brain of AIDS patients

Human cytomegalovirus (HCMV) is one of the major pathogens causing neurologic disease in the immunocompromised host. A competitive nested polymerase chain reaction (PCR) was used to determine DNA load, distribution, and sequence variability of HCMV genomes in the brain of AIDS patients with and without HCMV encephalitis confirmed by histology and immunocytochemistry. By quantitative PCR, HCMV genomes were found to be distributed diffusely in the central nervous system (CNS) of all five patients with histologically proven HCMV encephalitis, but also in the brain of five of eight AIDS patients without neuropathological evidence of HCMV encephalitis. The viral DNA load in cases with HCMV encephalitis was increased 10- to 1, 000-fold as compared to patients without evidence of encephalitis. A viral load above 6, 000 copies HCMV/106 copies β-globin was found to be highly suggestive for HCMV encephalitis. Characterization of PCR products by temperature gradient gel electrophoresis (TGGE) and direct sequencing allowed us to detect a sequence variability of the amplified fragment of HCMV glycoprotein B (gB) among different patients, but also among different HCMV foci within the same patient. Furthermore, two of five AIDS patients with HCMV encephalitis most likely experienced double infections with different HCMV strains. The experimental procedure described in this study should also be applicable to the detection of significant HCMV DNA levels in biopsy samples. © 1995 Wiley-Liss, Inc.