Biomedical subjects

K B Dear

Publications and source records attributed to K B Dear.

21 records · Page 2Linked to original sources

PubMed1992

Traits that influence longevity in mice: a second look.

Analysis of genetic interactions in the F2 of an intercross of (C57BL/6 x DBA/2) F1J revealed influences of genetic factors on life span. Females lived longer than males. Dilute brown females died sooner than females of other colors. H-2b/H-2b males died sooner than H-2b/H-2d or H-2d/H-2d males, except that among dilute brown males those of typeH-2b/H-2d died sooner. Cluster analysis suggested that male and female genotypes each fall into two groups, with female dilute brown mice having shorter lives than other females, and male H-2b/H-2b mice except dilute brown and dilute brown H-2b/H-2d mice having shorter lives than other males. The association of heterozygosity with life span was clearer in females than in males, yet the longest-lived female genotype was homozygous H-2d/H-2d, of dominant Black phenotype at the Brown locus of chromosome 4, and homozygous dd at the Dilute locus of chromosome 9. The shortest-lived females were dilute brown H-2b/H-2b. The longest-lived and shortest-lived male genotypes were dilute brown H-2d/H-2d and dilute brown H-2b/H-2d, respectively. Although histological findings at postmortem differed between the sexes, there was no association of particular disorders with other genetic markers. The importance of H-2 in males was confirmed, but the allelic effects were perturbed, possibly by the absence of Sendai infection in this experiment. Overall our studies suggest that genetic influences on life span involve interactions between loci, and allelic interactions may change with viral infections or other environmental factors.

Animals↗

PubMed1992

Attempted prevention of blast crisis in chronic myeloid leukemia by the use of pulsed doses of cytarabine and lomustine. A Cancer and Leukemia Group B study.

An attempt to prevent the blast crisis in chronic myeloid leukemia by the use of pulsed doses of (cytarabine cytosine arabinoside) and lomustine was attempted as a cooperative group study by Cancer and Leukemia Group B. The basis for this study was to delay the development of blast crisis by pulsing dose of drugs known to be effective against emerging "blast" cells. The experimental arm which consisted of cytarabine and lomustine did not produce overall results superior to conventional treatment with busulfan. This was related to the non-hematologic effects of the combination which produced significant gastrointestinal toxicity leading to relatively early discontinuation of the combination. Nevertheless, the trial design allowed relatively prompt discontinuation of experimental arm and cross-over to conventional treatment with either hydrea or busulfan. No evidence existed that the use of new drug combinations in CML prejudiced the patient's chance to response to conventional chemotherapy. Thus, a role model for future trials in this disease was developed. With the development of the interferons and other experimental forms of therapy this conceptual development may be of significance.

Antineoplastic Combined Chemotherapy Protocols↗

PubMedDate not supplied

Postoperative patient-controlled analgesia: meta-analyses of initial randomized control trials.

STUDY OBJECTIVE: To compare outcomes during conventional analgesia (as-needed intramuscular dosing) and patient-controlled analgesia (PCA) in postoperative patients by analyzing data from published comparative trials. DESIGN: Meta-analyses of 15 randomized control trials. PATIENTS: Seven hundred eighty-seven adult patients (aged 16 to 65) undergoing various operative procedures. INTERVENTIONS: Either PCA or conventional analgesia for postoperative pain control. MEASUREMENTS AND MAIN RESULTS: Data were extracted on analgesic efficacy, analgesic use, patient satisfaction, length of hospital stay, and side effects. Meta-analyses of the data showed the following: (1) greater analgesic efficacy when PCA was used, with a mean additional benefit of 5.6 on a scale of 0 to 100 (SED, 2.2; p = 0.006); (2) a nonsignificant trend toward reduced analgesic use in PCA patients, based on a count of trials finding in one direction or the other (p = 0.092); (3) a 42% difference in the proportion of patients expressing satisfaction over dissatisfaction (SED, 20%; p = 0.02), with PCA being preferred; (4) a nonsignificant trend toward shortening of length of hospital stay with PCA use (mean, 0.15 days, SED, 0.13; p = 0.24); (5) no significant differences in the occurrence of any side effect. CONCLUSIONS: Patient preference strongly favors PCA over conventional analgesia. Patients using PCA also obtain better pain relief than those using conventional analgesia, without an increase in side effects. Favorable effect of PCA upon analgesic usage and length of hospital stay did not in the initial trials attain statistical significance. Nonetheless, the favorable trends in the mean effect sizes for both outcomes argue that further studies of both outcomes should be performed to determine whether the favorable impact of PCA upon either may become statistically significant if larger numbers of patients are enrolled.

Analgesia↗