Biomedical subjects
M F Hansen
Publications and source records attributed to M F Hansen.
Preliminary assessment of computed tomography and satellite teleradiology from Operation Desert Storm.
Computed tomography at military transportable hospitals was used for the first time during the recent Operation Desert Storm in the Saudi Arabian desert. Scan quality was excellent and the scans proved clinically important in patient management. A teleradiology link via satellite to the U.S. mainland was also successfully employed. The objectives of the teleradiology link were to validate the concept distant interpretation of images obtained on the battlefield and to provide specialty radiology consultation. This technology shows great promise for future applications, both for combat casualty care and for civilian disaster medical support operations.
Molecular genetic considerations in osteosarcoma.
Osteosarcoma tumorigenesis is consistent with a model by which tumorigenesis results if both alleles at the retinoblastoma susceptibility locus (RBI) are altered. Additional genetic evidence strongly suggests that another obligate event in osteosarcoma tumorigenesis is the homozygous alteration of another gene, p53. Both the RB1 gene and p53 have been proposed to act as tumor-suppressor genes, suggesting that, in this instance, tumorigenesis is the result of the loss of gene function of these two genes, rather than a gain of function.
Structural alterations at the putative retinoblastoma locus in some human leukemias and preleukemia.
Homozygous loss of alleles of the retinoblastoma susceptibility locus (RB1) has been implicated in the onset of many different solid tumors. Heterozygous deletions of chromosome 13q14, the region containing the RB1 locus, have been observed by us in several subvariants of leukemia and preleukemia. We examined four cases of leukemia and one case of preleukemia for homozygous inactivation of the RB1 locus; in at least one case, evidence supports the concept that homozygous loss of both alleles of RB1 was an important step during leukemogenesis.
Codon 72 polymorphism of the TP53 gene.
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Loss of genetic information in cancer.
The determination and comparison of genotypic combinations at genomic loci in normal and tumour tissues from patients with various types of cancer have defined the chromosomal locations of loci at which recessive mutations play a role in disease. The predisposing nature of some of these mutant alleles is exemplified in studies of retinoblastoma and osteogenic sarcoma. These two clinically associated diseases share a pathogenetically causal predisposition that maps to chromosome position 13q14. A similar mechanism at 11p15.5 is involved in the development of the embryonal variant of rhabdomyo-sarcoma, Wilms' tumour and hepatoblastoma. Finally, genomic alteration of chromosome 10 is apparent in glioblastomas and mixed tumours of glioblastoma/astrocytoma grade III but not in homogenous astrocytoma grades II or III, suggesting the definition of a locus involved in tumour progression and, perhaps, an approach to molecular genetic staging of tumours.
Molecular detection of chromosomal translocations that disrupt the putative retinoblastoma susceptibility locus.
A candidate DNA sequence with many of the properties predicted for the retinoblastoma susceptibility (RB1) locus has been cloned (S. H. Friend, R. Bernards, S. Rogelj, R. A. Weinberg, J. M. Rapaport, D. M. Albert, and T. P. Dryja, Nature [London] 323:643-645, 1986). The large size of this gene (ca. 200 kilobases [kb]) and its multiple dispersed exons (Wiggs et al., N. Engl. J. Med. 318:151-157, 1988) complicate molecular screening strategies important in prenatal and presymptomatic diagnosis and in carrier detection. Here we used field inversion gel electrophoresis (FIGE) to construct a restriction map of approximately 1,000 kb of DNA surrounding the RB1 locus and to detect the translocation breakpoints in three retinoblastoma patients. DNA probes from either the 5' or 3' end of the gene were used to detect a 250-kb EagI restriction fragment in DNA from unaffected individuals. Both probes identified an additional hybridizing fragment in the DNA from each patient, permitting the breakpoints in all three to be mapped within the cloned RB1 gene. Analysis of the breakpoint in one translocation cell line allowed the RB1 gene to be oriented with its 5' end toward the centromere. The 5' end of the gene also appeared to be associated with a clustering of sites for several infrequently cleaving restriction enzymes, indicating the presence of an HpaII tiny fragment island. The detection and mapping of the translocation breakpoints of all three retinoblastoma patients to within the putative RB1 gene substantiated the authenticity of this candidate sequence and demonstrated the utility of FIGE in detecting chromosomal rearrangements affecting this locus.
Tumor suppressors: recessive mutations that lead to cancer.
Several lines of evidence point to the involvement of recessive mutations in the predisposition to, and hence initiation of, cancer in vivo. Analyses of the genetic behavior of transformed cells suggest that at least one way to explain these events is to invoke loci which suppress the tumorous phenotype and which are inactivated by mutation. These suppressors are the subject of much speculation, but whether or not they are ultimately determined to be the regulators of differentiation antigens, growth factors, or proto-oncogenes, it is certain that the investigation of such loci will allow yet another glimpse at the inner mysteries of organismal development.
Retinoblastoma and the progression of tumor genetics.
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Genetics of cancer predisposition.
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Mothers' problem-solving skill and use of help with infant-related issues: the role of importance and need for action.
Examination was made of the relationship of mothers' appraisal of the importance of and need for action around infant-related issues to maternal experience (parity and time since birth), use of help, and perceived problem-solving competence. Sixty-two mothers (38 primiparae and 24 multiparae) kept for 90 days post-birth a daily log of issues, rated for importance and for need for action, and of help used. Mothers also reported perceived problem-solving competence on an 11-item scale. Findings indicated tentativeness in ratings of importance and action. Ratings of importance were associated with action ratings, except for temperament issues. Action ratings for baby care and illness issues decreased significantly with time. Otherwise, maternal experience had no effect on ratings. More of the variance in perceived competence than use of help was explained by action and importance ratings.
Heterakis gallinarum: radioimmunoassay of antigenic molecules in parasite cuticular extracts.
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Retinoblastoma and osteosarcoma: the prototypic cancer family.
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Helping children deal with procedures in a clinic setting: a developmental approach.
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Recessive mutant genes predisposing to human cancer.
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Molecular genetics of human familial cancer.
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Life with a new baby: stressors, supports, and maternal experience.
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Pseudoaneurysms complicating pancreatitis: detection by CT.
Complications of pancreatitis such as pseudocyst formation and abscess are well known to radiologists. Secondary formation of pseudoaneurysms has not been emphasized in the radiologic literature. The great morbidity and mortality associated with pseudoaneurysms emphasize the importance of early detection. Three patients are described whose angiographically proved pseudoaneurysms were demonstrated on contrast material-enhanced abdominal CT scans obtained for evaluation of pancreatitis. A homogeneously enhancing structure within or adjacent to a pancreatic pseudocyst or contiguous with a vascular structure should be considered highly suspicious for an associated pseudoaneurysm.