Comparative genomics of the human and mouse T cell receptor loci.

The availability of the complete genomic sequences of the human and mouse T cell receptor loci opens up new opportunities for understanding T cell receptors (TCRs) and their genes. The full complement of TCR gene segments is finally known and should prove a valuable resource for supporting functional studies. A rational nomenclature system has been implemented and is widely available through IMGT and other public databases. Systematic comparisons of the genomic sequences within each locus, between loci, and across species enable precise analyses of the various diversification mechanisms and some regulatory signals. The genomic landscape of the TCR loci provides fundamental insights into TCR evolution as highly localized and tightly regulated gene families.

Increased lymphocyte replicative index following 2,4-dichlorophenoxyacetic acid herbicide exposure.

OBJECTIVE: Evaluate peripheral blood lymphocyte proliferation (replicative index:RI) and micronuclei frequency (MF) among 2,4-D herbicide applicators. METHODS: Twelve applicators spraying only 2,4-D provided a blood and urine specimen upon enrollment, several urine samples during the spraying season, and a blood specimen at the study's end. Nine controls provided blood and urine specimens upon enrollment and at the study's end. Gas chromatography/tandem mass spectroscopy determined urinary 2,4-D levels and standard in-vitro assays determined RI and MF scores. Applicator RI and MF were compared before and after spraying and with controls. RESULTS: Applicators contributed 45 urine specimens with concentrations ranging from 1.0 to 1700 (microg 2,4-D/g creatinine/L urine) that logarithmically (In) increased as spraying time increased. Applicator RI increased after spraying (p = 0.016), independent of tobacco and alcohol use, and demonstrated a weak dose-response with increasing urinary 2,4-D levels (p = 0.15). Among 2,4-D applicators, pre-exposure complete blood counts and lymphocyte immunophenotypes were not significantly different from post-exposure measurements. CONCLUSION: Urinary 2,4-D concentration, an exposure biomarker, may be associated with lymphocyte replicative index, a cell proliferation biomarker.

Very long survival in pediatric cancer between 1944 and 1993.

OBJECTIVE: To identify factors associated with very long survival among all cancer cases diagnosed at age 19 years or younger registered by the Cancer Data Service at the University of Kansas Medical Center in Kansas City, Kansas, U.S.A. in the 40-year period between 1944 and 1983, with follow-up to 1993. METHODS: There were 2720 pediatric patients with 2750 cancers who were studied. Forty-four types of cancer were grouped into 11 diagnostic categories. Diagnosis years spanned four eras: 1944-1953, 1954-1963, 1964-1973, and 1974-1983. Cases were compared using specific characteristics and were divided into short-term and long-term survivors with the division generously set at seven years. The proportions of the long-term survivors were compared by specific characteristics. RESULTS: Among the diagnostic categories, leukemias were the most common (29.8%), followed by CNS tumors (15.2%), and Hodgkin's disease (9.0%). Male to female ratio was 4:3; average age at diagnosis was 8.83 +/- 6.08 years. Long-term survivors totaled 1148 (41.7%). Prognosis was better in cases diagnosed in earlier stages and in later eras. Proportion of long-term survivors increased from 18.7% in era I to 52.6% in era IV. Improvement of survival was statistically significant in most diagnostic categories. CONCLUSIONS: This study shows continuing improvement of survival during four consecutive eras for childhood and adolescent cancer. Early diagnosis was associated with better survival. Unstaged cases decreased over time reflecting progress in diagnostic techniques. Many patients died before seven years after diagnosis. Those who survived more than seven years had excellent survival. Pediatricians can expect to participate in the care of these patients long after the original dianosis and treatment.

An analysis of the suitability of home health visits for telemedicine.

To determine what percentage of traditional home health nursing visits could be done by telemedicine, we carried out a retrospective review of nursing charts (clinical records). Data of two types were recorded. The objective data, which were abstracted from the records, included demographic information, patient assessments, teaching activities and interventions. The subjective data were the opinions of four observers as to whether the visit could have been done using currently available telemedicine technology. Records were sampled randomly for patients who had received home nursing care from three home health agencies in rural and urban areas during the winter and summer of 1996. A 54-item coding instrument was applied to 906 different charted home nursing visits. For 412 (46%) of these, the on-site nursing could reasonably have been replaced by telenursing. Significant factors determining the possible use of telenursing included primary diagnosis, number of interventions and patient age. Among the 10 most common primary diagnoses, the most amenable to telenursing care were chronic airway obstruction and joint disorders; the least amenable were coagulation disorders and anaemia. Telenursing visits could substitute for a substantial fraction of on-site home nursing visits. This has important implications in terms of reducing the cost of home nursing care.

A cost measurement study for a tele-oncology practice.

The costs of providing oncology services in three different ways were measured. Services were provided to a peripheral hospital by: conventional clinics, in which the oncologist worked at the hospital concerned; outreach clinics, in which an oncologist was flown in periodically from a central hospital; telemedicine clinics, in which the oncologist at the central hospital practised via a video-link. During a one-year study period, 2400 patients were seen in conventional clinics, 81 in outreach clinics and 103 in telemedicine clinics. At these workloads the average costs per patient were $149, $897 and $812, respectively. However, the average costs cannot be compared directly without further information about the shape of the unit cost curves.

Analysis of the 1.1-Mb human alpha/delta T-cell receptor locus with bacterial artificial chromosome clones.

Bacterial artificial chromosome (BAC) clones are effective mapping and sequencing reagents. The 1.1-Mb alpha/delta T-cell receptor locus of humans was mapped and partially sequenced with BAC clones. Seventeen BAC clones covered the 1.1-Mb alpha/delta locus, with the exception of one small gap that was expected from the coverage that a 3.7-fold BAC library is likely to provide. The end sequences of the BAC inserts could be obtained directly from the BAC DNA by sequencing with the chain terminator chemistry. Five complete BAC inserts were sequenced directly by the shotgun approach. The ends of the 17 BAC inserts were distributed evenly across the locus. By several independent criteria, the BAC clones faithfully represented the genomic DNA, with the exception of a single clone with a 68-kb deletion. These BAC features led to the proposal of a new approach to sequence the human genome.

A cost analysis of a tele-oncology practice.

Costs were monitored for three different types of oncology practice: a telemedicine clinic and a fly-in outreach clinic, both held in rural areas, and a traditional clinic held in a city hospital. Total expenses were calculated over the year May 1995 to April 1996. The average cost per telemedicine visit was $812. The average cost per outreach clinic visit was $897. Flying in oncology support for this practice was therefore about 10% more costly than telemedicine. While the outreach cost may have been inappropriately high due to a slow start-up phase, it was still less expensive during this period to be seen via telemedicine. For comparison, the average cost per traditional oncology clinic visit was $149. However, this figure does not take into account the costs of access to a city-based service by rural patients.