Improvements in snap-shot nuclear magnetic resonance imaging

New variants of the ultra-high-speed echo-planar imaging technique have been used to obtain snap-shot images of adult patients and volunteers at 0.1 T. Modified pulsed-gradient sequences together with non-linear signal sampling and activity screened gradients have greatly improved the image quality obtainable by single-shot methods. A particular variant, modulus blipped echo-planar single-pulse technique (MBEST), although slightly slower than the blipped echo-planar single-pulse technique (BEST), is experimentally more robust and incorporates intrinsic T2 weighting. An account of these improvements together with some experimental results is presented.     

Development of biological diversity and susceptibility to chemotherapy in murine cancer metastases

We studied the development of biological heterogeneity in a spontaneous melanoma metastasis of clonal origin as demonstrated by karyotypic analysis. The metastatic potential and sensitivity to different chemotherapeutic agents varied both among and within clones of this metastasis isolated either in vitro or in vivo. This finding indicates that, even within a metastasis of clonal origin, cellular heterogeneity for chemotherapy or metastatic potential can develop rapidly and provides a mechanism for the emergence of resistance to therapy. Since most cancer deaths result from metastases that do not respond to treatment, the implications of these findings for the treatment of cancer are clear. Treatment modalities must be designed that circumvent the biological heterogeneity that can develop rapidly within each metastasis and among metastases.     

Perinatal toxicity of domestic naphthalene exposure.

Naphthalene-containing mothballs can cause methemoglobinemia on inhalation. We describe a mother with hemolytic anemia and methemoglobinemia associated with elevated levels of naphthalene following exposure to mothballs. Her newborn infant had identical symptoms requiring mechanical ventilation and an exchange transfusion for resolution.     

The development of a computerized assessment for minor psychiatric disorder

This paper describes the development, validation and use of a computerized assessment for minor psychiatric disorder based on the Clinical Interview Schedule (CIS; Goldberg et al. 1970). There was good agreement between the computerized assessment and the CIS administered by psychiatrists, both in assessing overall severity and in defining 'cases' of psychiatric disorder. Individual symptoms elicited by the computer and the CIS were compared, and the levels of agreement found were similar to those from inter-observer studies of standardized interviews. Subjects from a variety of non-psychiatric settings regarded the assessment as acceptable, accurate and easy to use. It is concluded that this computerized assessment of neurotic symptoms is valid and reliable. It eliminates observer bias, it is an efficient use of research resources and it may have clinical applications in primary care.     

S13, a rapidly oncogenic replication-defective avian retrovirus

The avian leukemia sarcoma virus S13 transforms chicken and Japanese quail embryo fibroblasts and chicken erythroid cells in tissue culture. S13-induced erythroid transformation requires culture conditions suitable for the growth of normal erythroid precursors (H. Beug and M. J. Hayman (1984), Cell 36, 963-972). S13-transformed erythroid colonies contain a high percentage of cells that differentiate in absence of erythropoietin. S13 is defective in pol and env functions but can code for a complete set of gag proteins. Nonproducer cell clones transformed by S13 release a noninfectious viral particle containing gag but no functional env or pol proteins. They also synthesize a transformation-specific protein of 155,000 molecular weight. This protein reacts with antibody to viral envelope glycoproteins and appears to represent onc as well as env sequences. The 155,000-molecular weight env-linked protein does not cross react immunologically with an antiserum against the v-erb A and v-erb B gene products.     

Smokeless tobacco use by youth in the U.S

Oral snuff and chewing tobacco, commonly referred to as smokeless tobacco, are being used by many adolescent and young adult males, and no indication exists that use by this group is declining. Users are at risk for oral cancer, noncancerous oral pathology such as leukoplakias, and addiction. Information about patterns of smokeless tobacco use and motivations of users may help planners develop and implement interventions. Variables include the importance of peer and family influences, social image, knowledge of harmful effects, regional differences, use of other substances, and addiction. Due to the addictive nature of smokeless tobacco, older youth may need cessation programs. Health educators are encouraged to include smokeless tobacco in their tobacco use prevention programs and to develop and implement comprehensive tobacco interventions appropriate for their youth population.     

Syndrome of erythroderma, failure to thrive, and diarrhea in infancy: a manifestation of immunodeficiency

Five infants with a triad of symptoms comprising generalized erythroderma, failure to thrive, and diarrhea are presented. All of these children demonstrated significant immunologic abnormalities. This is a recognizable clinical syndrome that reflects immunodeficiency; however, the responsible immunodeficiencies do not appear to be the same in every case. Early investigation and appropriate therapy may considerably reduce morbidity, and mortality in children with this syndrome.     

A recombinant bcl-x s adenovirus selectively induces apoptosis in cancer cells but not in normal bone marrow cells.

Many cancers overexpress a member of the bcl-2 family of inhibitors of apoptosis. To determine the role of these proteins in maintaining cancer cell viability, an adenovirus vector that expresses bcl-xs, a functional inhibitor of these proteins, was constructed. Even in the absence of an exogenous apoptotic signal such as x-irradiation, this virus specifically and efficiently kills carcinoma cells arising from multiple organs including breast, colon, stomach, and neuroblasts. In contrast, normal hematopoietic progenitor cells and primitive cells capable of repopulating severe combined immunodeficient mice were refractory to killing by the bcl-xs adenovirus. These results suggest that Bcl-2 family members are required for survival of cancer cells derived from solid tissues. The bcl-xs adenovirus vector may prove useful in killing cancer cells contaminating the bone marrow of patients undergoing autologous bone marrow transplantation.