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Biomedical subjects

A V Nguyen

Publications and source records attributed to A V Nguyen.

10 recordsLinked to original sources
PubMed2001

Colony-stimulating factor 1 promotes progression of mammary tumors to malignancy.

In human breast carcinomas, overexpression of the macrophage colony-stimulating factor (CSF-1) and its receptor (CSF-1R) correlates with poor prognosis. To establish if there is a causal relationship between CSF-1 and breast cancer progression, we crossed a transgenic mouse susceptible to mammary cancer with mice containing a recessive null mutation in the CSF-1 gene (Csf1(op)) and followed tumor progression in wild-type and null mutant mice. The absence of CSF-1 affects neither the incidence nor the growth of the primary tumors but delayed their development to invasive, metastatic carcinomas. Transgenic expression of CSF-1 in the mammary epithelium of both Csf1(op)/Csf1(op) and wild-type tumor-prone mice led to an acceleration to the late stages of carcinoma and to a significant increase in pulmonary metastasis. This was associated with an enhanced infiltration of macrophages into the primary tumor. These studies demonstrate that the growth of mammary tumors and the development to malignancy are separate processes and that CSF-1 selectively promotes the latter process. CSF-1 may promote metastatic potential by regulating the infiltration and function of tumor-associated macrophages as, at the tumor site, CSF-1R expression was restricted to macrophages. Our data suggest that agents directed at CSF-1/CSF-1R activity could have important therapeutic effects.

Animals↗
PubMed2000

Secure, web-accessible call rosters for academic radiology departments.

Traditionally, radiology department call rosters have been posted via paper and bulletin boards. Frequently, changes to these lists are made by multiple people independently, but often not synchronized, resulting in confusion among the house staff and technical staff as to who is on call and when. In addition, multiple and disparate copies exist in different sections of the department, and changes made would not be propagated to all the schedules. To eliminate such difficulties, a paperless call scheduling application was developed. Our call scheduling program allowed Java-enabled web access to a database by designated personnel from each radiology section who have privileges to make the necessary changes. Once a person made a change, everyone accessing the database would see the modification. This eliminates the chaos resulting from people swapping shifts at the last minute and not having the time to record or broadcast the change. Furthermore, all changes to the database were logged. Users are given a log-in name and password and can only edit their section; however, all personnel have access to all sections' schedules. Our applet was written in Java 2 using the latest technology in database access. We access our Interbase database through the DataExpress and DB Swing (Borland, Scotts Valley, CA) components. The result is secure access to the call rosters via the web. There are many advantages to the web-enabled access, mainly the ability for people to make changes and have the changes recorded and propagated in a single virtual location and available to all who need to know.

Academic Medical Centers↗
PubMed2000

Transforming growth factor beta3 induces cell death during the first stage of mammary gland involution.

Involution of the mammary gland following weaning is divided into two distinct phases. Initially, milk stasis results in the induction of local factors that cause apoptosis in the alveolar epithelium. Secondly after a prolonged absence of suckling, the consequent decline in circulating lactogenic hormone concentrations initiates remodeling of the mammary gland to the virgin-like state. We have shown that immediately following weaning TGFbeta3 mRNA and protein is rapidly induced in the mammary epithelium and that this precedes the onset of apoptosis. Unilateral inhibition of suckling and hormonal reconstitution experiments showed that TGFbeta3 induction is regulated by milk stasis and not by the circulating hormonal concentration. Directed expression of TGFbeta3 in the alveolar epithelium of lactating mice using a beta-lactoglobulin promoter mobilized SMAD4 translocation to the nucleus and caused apoptosis of these cells, but not tissue remodeling. Transplantation of neonatal mammary tissue derived from TGFbeta3 null mutant mice into syngenic hosts resulted in a significant inhibition of cell death compared to wild-type mice upon milk stasis. These results provide direct evidence that TGFbeta3 is a local mammary factor induced by milk stasis that causes apoptosis in the mammary gland epithelium during involution.

Animals↗
PubMed1995

Analysis of Salmonella enteritidis isolates by arbitrarily primed PCR.

An arbitrarily primed PCR (AP-PCR) was developed to analyze the genomic DNAs of Salmonella enteritidis isolates from human outbreaks and from avian sources. The AP-PCR generated seven distinct randomly amplified DNA patterns among the S. enteritidis isolates studied. Differences in the DNA patterns among isolates of S. enteritidis phage types 13a and 8 as well as among S. enteritidis phage type 14b were observed. The AP-PCR analysis can be used to determine the differences among isolates within the same phage types and may be useful for tracing back the source of S. enteritidis outbreaks in humans more precisely.

Animals↗
PubMed1994

S-100 protein-negative malignant melanoma: fact or fiction? A light-microscopic and immunohistochemical study.

S-100 protein is considered a characteristic immunohistochemical marker for all nevomelanocytic lesions, in which it is expected to be present consistently. We reviewed 17 cases of malignant melanomas that previously tested negative for S-100 protein. They were reevaluated by light microscopy, a broad panel of immunohistochemical reagents including monoclonal and polyclonal antibodies to S-100 protein, and electron microscopy. On reexamination, five of the 17 cases were reclassified as non-melanoma tumors, and eight of the 17 cases were found to be positive for S-100 protein (six with monoclonal and eight with polyclonal antibodies) and HMB-45 antigen, consistent with melanoma. The remaining four cases repeatedly tested negative for S-100 protein despite various antigen enhancement methods, but they were positive for HMB-45 antigen and contained premelanosomes or melanosome-like structures by electron microscopy. Two of these repeatedly S-100 negative melanomas were acrally located; although the numbers are small, a possible relationship to a specific anatomic location cannot be excluded. These findings suggest that in a small subset of melanomas S-100 protein is either not fully expressed or is below the level that can be detected by routine immunohistochemistry. We also conclude that in the majority of the initially S-100-negative cases of melanomas, the misdiagnosis may occur due to the use of an incomplete immunohistochemical panel, technical reasons, or the inherent variability of tissue expression of S-100 protein.

Antigens, Neoplasm↗
PubMed1993

Differentiation of basal cell carcinoma.

Basal cell carcinoma is undoubtedly the most common malignancy in light-skinned people. Because of the high incidence of this type of carcinoma, physicians should be familiar with its many clinical presentations. An understanding of the behavior, multiple histologic variations, and available therapeutic modalities is of great value in the diagnosis and treatment of this tumor.

Basal Cell Carcinoma↗
PubMed1992

Malignant eccrine spiradenoma. A clinicopathologic study.

UNLABELLED: Malignant eccrine spiradenomas (MES) are exceedingly rare and their immunohistochemical and ultrastructural features have not been fully characterized. We studied two cases, one of them immunohistochemically and electron microscopically. Patient 1 had a 25-year history of multiple exophytic tumors involving the scalp, the skin of the face, and the torso. Of the lesions removed, ten were spiradenomas, two with malignant changes, and three were cylindromas. The malignant areas showed loss of tubular and nesting patterns, lack of two cell populations, and contained anaplastic cells with high mitotic rate. The immunohistochemical findings were consistent with eccrine differentiation. Patient 2 had a cystlike mass of long duration in the right groin. Histologically, the mass consisted of nodules of benign eccrine spiradenomas adjacent to a ductal-cystic mass lined by anaplastic cells, but areas of squamous and glandular differentiation were also present. CONCLUSIONS: (a) Case 1 is probably the first reported MES associated with multiple spiradenomas and cylindromas. (b) Cytodifferentiation in MES is variable, sometimes with almost complete loss of eccrine differentiation. (c) Identification of adjacent spiradenomas may be required for definite diagnosis of MES. (d) Clinical history of longstanding lesions with recent fast growth warrants tissue diagnosis.

Adenoma, Sweat Gland↗
PubMedDate not supplied

A Salmonella-specific DNA probe and its use in southern hybridization for differentiation of Salmonella enteritidis.

Chromosomal DNA from phage type 13a and Phage type 8 of Salmonella enteritidis (SE) was cloned in Escherichia coli using the plasmid pUC8. A 2.1-kilobase-pair (kbp) DNA fragment specific for Salmonella spp. was identified by colony, dot, and Southern hybridization analyses. When labeled and used as a probe (C7), this recombinant clone hybridized with the DNA of 18 Salmonella species but did not hybridize with the DNA of seven other enteric and non-enteric bacterial species. In Southern blot hybridization, this probe hybridized specifically to a 6.0 kbp BglI-digested DNA fragment of 17 SE isolates from human as well as avian sources, thus differentiating this fragment from DNA of 17 other Salmonella species. The C7 probe also hybridized to a 5-kbp fragment of one SE DNA derived from human and two SE DNA from poultry sources. This may indicate variation among SE isolates.

Blotting, Southern↗
PubMedDate not supplied

Amplification of Salmonella chromosomal DNA using the polymerase chain reaction.

A Salmonella-specific polymerase chain reaction (PCR) was developed and standardized. The origin of the primers was a recombinant clone (C7) that contained Salmonella-specific HindIII fragment DNA of 2.1-kilobase pairs. Based on the sequence data of Salmonella enteritidis recombinant clone C7, two primers designated NK1 (21 nucleotides) and NK2 (24 nucleotides) were synthesized for use in the PCR. A Salmonella-specific 2.0-kilobase pair DNA product was amplified by the primers from 23 species of Salmonella, but not from 19 enteric and non-enteric bacteria. As little as 330 fg of Salmonella DNA was detected using either ethidium bromide/ultraviolet exposure of gels or Southern blot hybridization with a C7 clone.

Animals↗