Interim targeting: a productivity improvement method that works.
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Efficiency↗
Biomedical subjects
C Peterson
Publications and source records attributed to C Peterson.
Prostitutes and public health services cooperate on AIDS--prevention in Brazil.
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Acquired Immunodeficiency Syndrome↗
Interrater reliability of roentgenological evaluation of the lumbar spine in lateral bending.
Interrater reliability is described for the evaluation of lumbar motion and motion coupling patterns in lateral bending. Upright neutral and lateral bending lumbar films of 58 student volunteers were marked by three examiners. Segmental tilt, segmental rotation and motion categories were computed. The performance of the examiners was evaluated using the Kappa statistic and a comparison of rater discrepancy to the experimental measurement error. Although all three raters were proficient within the context of calculated measurement error, good reliability was not universally demonstrated. Concordance for rotation was moderate to good, while agreement for lateral bending was of questionable interpretation. Reliability for the segmental motion categories was good for L1-L4, but unacceptable at L5. The poor reliability at L5 resulted in unacceptable concordance for the lumbar global motion category for three raters. The use of lateral bending radiographs for categorization of the lumbar spine in clinical practice is questioned.
Adult↗
ANA-PAC carries collective clout.
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American Nurses' Association↗
The transverse cerebellar diameter cannot be used to assess gestational age in the small for gestational age fetus.
The transverse cerebellar diameter was obtained in 44 small for gestational age (SGA) fetuses between 27-42.8 weeks. Twenty-nine of 44 fetuses had antepartum and/or neonatal complications consistent with intrauterine growth retardation. The cerebellar diameter was normal in 12 (27.3%), between 1-2 SDs below the mean for gestational age in six (13.6%), and greater than 2 SDs below the mean in 26 (59.1%). Hence, the transverse cerebellar diameter cannot be used to assess gestational age in those fetuses suspected of being SGA.
Cerebellum↗
Strain-dependent decrease in glutamate binding to the N-methyl-D-aspartic acid receptor during aging.
Glutamate binding to the N-methyl-D-aspartic acid (NMDA) receptor decreases in two strains of aged mice. In BALB/c mice the Bmax values decline 16% by 10 months and 45% by 30 months of age when compared to 3 months. The Kd increased more by 10 months (+29%) than by 30 months (+14%). In the C57Bl strain the Bmax was unaltered by 10 months but decreased 17% by 30 months. The Kd values, however, increased 121% by 10 months and 283% by 30 months of age. These data suggest that the age-related decline in glutamate binding to the NMDA receptor may predict a strain-specific reduction in NMDA-mediated processes (e.g. long-term potentiation, postsynaptic calcium fluxes).
Aging↗
Development of N-methyl-D-aspartate excitotoxicity in cultured hippocampal neurons.
Immature hippocampal neurons (E-18) were maintained in defined medium for up to 3 weeks and their susceptibility to N-methyl-D-aspartic acid (NMDA)-induced cell death was studied at various days in vitro. Upon acute exposure to NMDA (5 min), hippocampal neurons in vitro (8-12 days after plating) showed cell body swelling and dendritic degeneration that preceded cell death 24 h later. NMDA-induced neurodegeneration could be prevented by MK-801 treatment but not by tetrodotoxin. In contrast, immature (5-7 days old) neurons were unaltered by exposure to 500 microM NMDA for either 5 min or 24 h. One explanation for the resistance of immature neurons to glutamate neurotoxicity may be related to maturation of the NMDA receptor complex. Glutamate binding to the NMDA receptor in vivo increased from 14.6 +/- 1.6% (0 day) to 55.2 +/- 4.5% (day 7), 79 +/- 4.9% (day 14), 93.8 +/- 2.8% (day 21) until it reached the adult Sprague-Dawley value of 100 +/- 0.8% (day 90).
Age Factors↗
Inhibition of radiogenic mammary carcinoma in rats by estriol or tamoxifen.
Mammary carcinomas have been induced by 3.5 Gy whole-body gamma radiation administered at age 40 to 50 days to virgin female Sprague-Dawley rats. In 142 irradiated controls carcinoma incidence averaged 7.8% in survivors observed less than 300 days and 38.3% of those surviving longer (P less than 0.001 by t test). Mammary cancer promotion was inhibited by two methods: estriol (E3) 638 micrograms/month (2.2 microns/mo) subcutaneously for natural life span begun 2 weeks after exposure reduced cancer incidence from 76% in controls to 48% after 331 to 449 mean days observation until neoplasia was palpable (P less than 0.02 by chi-square analysis). Uterine weights were similar in control and treated groups, and were 15% to 18% greater than uteri of nonirradiated controls from other simultaneous experiments. Six monthly 638-micrograms doses of 17 alpha ethinyl estriol (EE3) reduced tumors from 88% in controls to 64% (P less than 0.05 by chi-square analysis) and delayed cancer onset (P less than 0.01-0.04 by life table analysis). Ethinyl estradiol (EE2) after 6 months' treatment similarly delayed mammary tumor development reducing incidence to 75% (NS), with a six-fold increase in nonmammary epithelial malignant tumors. Estriol administration begun between 3 days before to 5 days after radiation did not alter mammary cancer incidence in six experiments. Monthly implantation of 2.5 mg tamoxifen (4.44 microns/mo) started 2 weeks after radiation reduced mammary cancer incidence from 83% to 14% after 307 to 314 days' observation (P less than 0.001 by chi-square analysis). Treated rats had atrophic ovaries and uteri consistent with blockade of endogenous estradiol activity. Short-term parenteral E3 or EE3 therapy using 10 to 30 micrograms/kg/day (35-100 microns/kg/day) rapidly differentiated virgin rat mammary glands without impairment of subsequent estrus cycles and offers an alternative to castration or life-long antiestrogen therapy for reduction of risk of radiogenic mammary carcinoma.
Animals↗
Sonographic detection of the fetal pancreas.
With the fetal stomach utilized as a general marker, targeted-imaging of the fetal abdomen was initiated to locate the pancreas. Overall, the pancreas was seen in 77 of 149 cases (51.7%). Menstrual age and the position of the fetus were significant factors in determining the frequency of pancreatic visualization.
Embryonic and Fetal Development↗
Variability of 6-mercaptopurine pharmacokinetics during oral maintenance therapy of children with acute leukemia.
The effects of some environmental and genetic factors on the inter- and intraindividual variations of 6-mercaptopurine (6-MP) pharmacokinetics were studied in children on oral remission maintenance therapy for acute lymphoblastic leukemia or non-Hodgkin's lymphoma. Blood samples were obtained 0-4 h after drug intake. 6-MP concentrations were determined in plasma and in erythrocyte concentrates. The influence of food on the pharmacokinetics was examined in a prospective study of 15 children. Each child was examined four times, twice in the fasted state and twice after intake of a standardized, milky, breakfast. There were pronounced inter- and intraindividual variations. Food intake seemed to reduce these variations but there were no significant changes in peak concentrations and area under the plasma concentration vs time curves (AUC) between the fasted and fed states. Food intake reduced the time to peak concentration both in plasma, from 1.8 h to 1.1 h (P less than 0.01) and in red blood cells, from 1.8 h to 1.3 h (P less than 0.01). Retrospective subdivision of the patients indicated a tendency for different pharmacokinetic patterns according to dose; five out of seven patients receiving greater than 70 mg m-2 had a higher AUC in the fasting state, while five out of eight patients receiving less than 70 mg m-2 had a higher AUC in the fed state. The cytochrome P-450-dependent hydroxylation capacity was evaluated with debrisoquine but no correlation was found to the pharmacokinetics of 6-MP.
Administration, Oral↗
Increasing the accumulation of daunorubicin in human leukemic cells by prolonging the infusion time.
Eight patients with acute nonlymphoblastic leukemia were treated with a combination of daunorubicin (1.5 mg/kg body weight) and cytosine arabinoside. The infusion time of daunorubicin was varied from 10 min to 24 h. One patient received the drug during 24 h in one treatment course and during 10 min in the subsequent course. The concentrations of daunorubicin and its main metabolite, daunorubicinol, were monitored simultaneously in plasma and in leukemic cells using high performance liquid chromatography. Infusion during 24 h gave a peak plasma concentration of daunorubicin that was less than one tenth of that observed after infusion for 10 min, while the areas under the plasma concentration vs time curves were similar. In contrast, prolonging the infusion time increased the area under the cellular concentration vs time curve from a mean of 3.3 nmol x h/mg cell protein for infusions less than one hour to 13.7 and 17.0 nmol x h/mg cell protein in two patients who received the same dose as a 24-h infusion. The duration of the infusion did not influence the intracellular levels of daunorubicinol. We conclude that the infusion times appear to affect the concentration of daunorubicin in the leukemic cells and may be important for the therapeutic effects of daunorubicin.
Cell Transformation, Neoplastic↗
Personal control and health promotion.
Personal control is an individual's belief about the degree that he or she can bring about good events and avoid bad events. High personal control is associated with intellectual, emotional, behavioral, and physiological vigor in the face of challenging situations and events; low personal control is associated with maladaptive passivity and poor morale. In this paper, we sketch the roots of the personal control concept and propose a composite theory of personal control. Then we apply this composite theory to health promotion, a field defined by a cluster of techniques without a unifying theory. We believe that the personal control concept can be the cornerstone for a theory of health promotion.
Attitude to Health↗
Pharmacokinetics of daunorubicin and doxorubicin in plasma and leukemic cells from patients with acute nonlymphoblastic leukemia.
The pharmacokinetics of daunorubicin and doxorubicin were studied in plasma and leukemic cells from 16 patients with acute nonlymphoblastic leukemia during 19 courses of treatment with the unconjugated or DNA-conjugated drugs. Daunorubicin and doxorubicin are high-clearance drugs with very high apparent volumes of distribution, indicating a pronounced tissue affinity. This was more pronounced in the case of doxorubicin and may explain the reduced cardiotoxicity of the DNA-complexes. Daunorubicin reached higher intracellular peak concentrations than doxorubicin, but the latter drug was retained much longer. The cell/plasma concentration ratio was higher for daunorubicin than for its reduced metabolite daunorubicinol. No doxorubicinol was found intracellularly. The observed differences in cellular pharmacokinetics between daunorubicin and doxorubicin may explain the difference between the clinical activity spectras of these two drugs. DNA-conjugation did not markedly modify the uptake of daunorubicin in the leukemic cells, whereas the mean intracellular accumulation of doxorubicin was 60% higher when the drug was administered as a DNA-conjugate. This may enhance the selectivity of doxorubicin in the treatment of acute leukemia.
Antineoplastic Combined Chemotherapy Protocols↗
6-mercaptopurine plasma levels in children with acute lymphoblastic leukemia: relation to relapse risk and myelotoxicity.
Plasma levels of 6-mercaptopurine were determined in 22 consecutive children with acute lymphoblastic leukemia on oral remission maintenance therapy during the time period of August 1984 to January 1988. Each child received the drug once daily for up to 3 years and was studied repeatedly (1-12 times). An HPLC method was used for drug analysis. We found large interpatient variations in the mean peak plasma concentration (range of 50-424 ng/ml) and in the mean area under the concentration vs. time from 0-4 h curve (range of 82-637 ng ml-1 h). There were also pronounced variations between different sampling occasions in the same patient. Nine of the 22 patients had complications during the maintenance therapy. Five children with a mean peak plasma level below 135 ng/ml and a mean area under the curve (AUC) value below 251 ng ml-1 h relapsed (three in the central nervous system and two in the bone marrow). Both children with a bone marrow relapse died. Relapse risk was related to the AUC (p less than 0.05). Four children with a mean peak plasma level above 166 ng/ml and a mean AUC value above 363 ng/ml/h developed severe myelotoxicity, which necessitated a temporary cessation of the maintenance therapy. In addition, two patient relapsed 6 and 11 months after termination of maintenance therapy. Their mean peak and AUC values were not low but the concentrations decreased markedly towards the end of the maintenance period. The results indicate that the plasma levels of 6-mercaptopurine, when determined repeatedly, might be of significance for the outcome of the remission maintenance treatment.
Adolescent↗
Accumulation of vincristine and doxorubicin in malignant lymphocytes with different immunophenotypes.
Cellular accumulation of vincristine (VCR) and doxorubicin (DOX) was studied in 15 patients with low-grade B-cell malignancies. Their leukemic lymphocytes were isolated and the effect of verapamil on drug uptake was studied. The immunophenotype was characterized using anti-IgM, -IgD, -B 1, monoclonal antibodies. The more that cells bound the IgD or B1 antibodies, the more vincristine and doxorubicin did they accumulate. The fewer the cells that bound IgM antibodies, the more drug did they accumulate.
Aged↗
Changes in calcium homeostasis during aging and Alzheimer's disease.
Several observations indirectly suggest that intracellular calcium regulation may be altered by aging and Alzheimer's disease. Thus, calcium homeostasis was examined directly in skin fibroblasts from Alzheimer's patients and compared to cells from normal young and elderly controls. Alterations in both bound and free calcium were noted; cells from Alzheimer's donors have higher levels of bound calcium but lower concentrations of free intracellular calcium when compared to cells from young and normal aged donors. These changes in calcium homeostasis may be physiologically significant, since processes that require transient elevations of intracellular free calcium, such as cell spreading, decline in the Alzheimer's cells. In summary, cultured skin fibroblasts from normal aged and Alzheimer's patients demonstrate deficits in calcium homeostasis and other metabolic processes when compared to cells from young donors.
Aging↗
Necrotizing fasciitis.
Early recognition of necrotizing fasciitis is the key to successful treatment. However, initial presentation of this disease is variable. In this case report, the first clinical evidence was a gram stain of the deep surface of the superficial fascia.
Biopsy↗
A combined historic and sonographic score for the detection of intrauterine growth retardation.
Sonographic analysis of fetal biometry has been useful in the antepartum detection of intrauterine growth retardation (IUGR). Little attention, however, has been focused upon elements of the maternal and fetal history that may significantly affect the likelihood of IUGR. To define more precisely both the clinical and sonographic parameters associated with IUGR, we studied the following variables: routine fetal biometry (biparietal diameter, head circumference, abdominal circumference, and femur length), fetal weight percentile, amniotic fluid volume, and an antenatal scoring system for IUGR. One hundred one consecutive fetuses with an estimated fetal weight at or below the tenth percentile for gestational age formed the study population. The results of multiple logistic regression analysis indicated that weight percentile was the single most important sonographic parameter in the detection of IUGR. Maternal history and femur length were also found to be important independent predictors of IUGR.
Birth Weight↗