Microsatellite analysis of synchronous and metachronous tumors: a tool for double primary tumor and metastasis assessment.

Despite well-established histopathological features and the development of immunostaining of human neoplasms, there are a number of cases in which surgical pathologists cannot assure the origin of synchronous and metachronous tumors. In many cases, the classification of these lesions as either two separate primary tumors or as a single primary tumor with a metastasis has significant implications with respect to patient prognosis and recommendations for therapy. To establish the origin of tumors, we assessed tumor cell clonality using PCR-based microsatellite analysis on microdissected archival tissues for loss of heterozygosity (LOH) and microsatellite instability (MSI) in a series of 19 paired synchronous and metachronous tumors from several organs. As a control group, 15 autopsy cases with an unequivocally recognizable primary tumor and associated metastases were also examined. Based on LOH and MSI findings, and using a panel of 4 to 12 (median 7) microsatellite markers, we were able to establish the clonal pattern of microsatellite changes in 17 out of 19 (89%) biopsy cases and thus determine if they were either double primary tumors (41%) or metastases (59%). Of interest, identical or similar pattern of microsatellite abnormalities were detected in 15 primary tumors and corresponding metastasis from autopsies. Our results indicate that microsatellite analysis for LOH and MSI, as an expression of clonality, provides a useful tool to distinguish double primary neoplasms and metastases in synchronous and metachronous tumors.     

Survival of satellite cells in whole muscle transplants

The ability of satellite cells to survive the ischemic conditions at the core of orthotopically free grafted rat extensor digitorum longus muscles was examined. Cell cultures of isolated core and peripheral regions of whole muscle grafts maintained in vivo for more than 24 hours indicated that no viable cells were present in the core, whereas the number of cells from the peripheral region was greatly increased. Muscles were examined with the electron microscope to determine the fate of satellite cells of the core at various times after transplantation. The population of satellite cells in the core was reduced beginning at 18 hours and had virtually disappeared by 24-28 hours. This reduction did not appear to be the result of satellite cell death. Although there was abundant morphological evidence that myonuclei as well as myofiber cytoplasmic organelles were degenerating, there was little indication of satellite cell death in situ any time period studied. These studies suggest that satellite cells cannot survive, but migrate from the ischemic core to more peripheral regions of whole muscle transplants. In addition, they suggest that migration is an important aspect of the regeneration response in the free graft system and permits the myogenic population to contribute en masse to the centripetal wave of regeneration from the time it is initiated at the muscle periphery.     

A cytogenetic study of 53 human gliomas

Cytogenetic studies were performed on human glioma samples obtained by stereotactic biopsy, stereotactic craniotomy, or routine craniotomy. Using in situ culture and robotic harvesting techniques, we obtained suitable metaphases in 50 (94%) of 53 tumors, including 28 diffuse astrocytomas, four juvenile pilocytic astrocytomas, two gliosarcomas, three other miscellaneous astrocytomas, eight oligodendrogliomas, four mixed oligodendroglioma-astrocytomas, and four ependymomas. Cytogenetic studies were performed only on primary cultures; the mean culture time was 9.6 days (range 1-31 days). One or more chromosomally abnormal clones were observed in 35 (66%) tumors. Eleven (21%) other specimens had random nonclonal chromosome abnormalities. In four (8%) specimens, no chromosome abnormalities were noted. The results of this study suggest that grade 3 and 4 tumors are more likely to contain an abnormal clone than tumors of grade 1 or 2 (p less than 0.01). The most common numeric chromosome abnormalities were -6, +7, -10, -13, -14, -15, -18, and -Y. The most common structural abnormalities involved 1p, 6q, 7q, 8p, 9p, 11p, 11q, 13q, and 19q. Four tumors had two or more independent clones and ten contained subclones demonstrating karyotype evolution. With in situ culture and robotic harvesting techniques, cytogenetic studies can be successful on nearly all human gliomas, including those derived from small stereotactic biopsies.     

Dynamic pressure transmission through agarose gels

In biomedical research, agarose gel is widely used in tissue culture systems because it permits growing cells and tissues in a three-dimensional suspension. This is especially important in the application of tissue engineering concepts to cartilage repair because it supports the cartilage phenotype. Mechanical loading, especially compression, plays a fundamental role in the development and repair of cartilage. It would be advantageous to develop a system where cells and tissues could be subjected to compression so that their responses can be studied. There is currently no information on the pressure response of agarose gel when pressure is applied to the gas phase of a culture system. To understand the transmission of pressure through the gel, we set up an apparatus that would mimic an agarose suspension tissue culture system. This consisted of a sealed metal cylinder containing air as well as a layer of agarose submerged in culture medium. Pressure responses were recorded in the air, fluid, gel center, and gel periphery using various frequencies, pressures, gel volumes, and viscosities. Regression analyses show an almost perfect linear relation between gas and gel pressures (r(2) = 0.99987, p < 0.0001, f(x) = 0.9982 x - 0.0286). The pressure transmission was complete and immediate, throughout the range of the applied pressures, frequencies, volumes, and viscosities tested. Applying dynamic pressure to the gas phase results in reproducible pressure in the agarose and, therefore, validates the use of agarose tissue culture systems in studies employing dynamic pressurization in cartilage tissue engineering.     

Humoral Immunity to Dietary Antigens in Atopic Dermatitis

Enzyme-linked immunosorbent assays (ELISA) employing a biotin-avidin amplification step are described for the quantification of human serum IgG antibodies to the dietary antigens ovalbumin (OA) and beta-lactoglobulin (BLG). The analytical quality of these assays was acceptable. Antibodies were measured in 16 patients with mild or moderate atopic dermatitis (AD), in 31 patients with a history of AD, and in closely matched controls. Levels of serum anti-OA antibodies did not differ in patients and controls, whereas anti-BLG antibodies tended to be higher in patients with mild or moderate AD than in controls (P less than 0.05).     

Structural and mutational analysis of the xeroderma pigmentosum group D (XPD) gene

Individuals affected by the autosomal recessive disease xerodermapigmentosum (XP) are acutely sensitive to sunlight and predisposedto skin cancer on exposed areas. Cells cultured from XP patientsare both UV sensitive and defective in the nucleotide excisionrepair of damaged DNA. These cellular phenotypes are amenableto experimental strategies employing complementation, an approachpreviously used to demonstrate the correction of XP-D phenotypesfollowing the introduction of the XPD (ERCC2) gene. In the presentstudy, we have characterized the genomic organization of theXPD (ERCC2) gene and found it to be comprised of 23 exons. Thesedata were helpful in evaluating the functional integrity ofalleles in two XP-D cell lines. In cell line GM436 a C     

Diffusion of oxygen and carbon dioxide through blood flowing in a channel

The numerical solutions of diffusion equations have been obtained for the cases of oxygen and carbon dioxide diffusing through blood flowing between two porous parallel planes. It is assumed that at the entrance to the channel the concentration profiles are uniform and the velocity profile is fully developed. The rheological characteristics of blood are described by the Casson equation. The computations have been made employing the explicit finite-difference forward-marching procedure. The results have been obtained for a wide range of yield numbers, inlet partial pressures, pH, membrane resistances and haemoglobin concentrations.     

Duchenne muscular dystrophy and myotonic dystrophy in the same patient

We report on the first patient identified with myotonic dystrophy and Duchenne muscular dystrophy (DMD). The family of the propositus had a strong history of myotonic dystrophy, and there was an intrafamilial pathological expansion of the responsible CTG repeat between the mildly affected mother (160 repeats; normal 27 repeats) and her more severely affected son (650 repeats), and his sister (650 repeats). The propositus was an isolated case of Duchenne muscular dystrophy with marked dystrophin deficiency in muscle biopsy. The patient was still ambulatory post age 16. Myotonic dystrophy could interfere to some extent with the progression of Duchenne dystrophy. However, other interpretations are possible. Twelve percent of dystrophin revertant fibers as observed by immunohistochemistry could be sufficient to ameliorate typical DMD clinical severity, or the patient may present a somatic mosaic. The pathophysiological interactions of these two unlinked disorders are discussed at the clinical and histopathological levels. © 1995 Wiley-Liss, Inc.