High-level amikacin resistance in Pseudomonas aeruginosa associated with a 3'-phosphotransferase with high affinity for amikacin

This work describes the characterization of the phosphotransferase enzymatic activity responsible for amikacin resistance in two clinical Pseudomona aeruginosa strains, isolated from a hospital that used amikacin as first-line aminoglycoside. Amikacin-resistant P. aeruginosa PA40 and PA43 (MIC: 128 mg/l) were shown to have APH activity with a substrate profile similar to that of APH(3′)-VI. The enzyme from P. aeruginosa PA40 was purified to >70% homogeneity. The K_m of amikacin for this enzyme was 1.4 μM, the V_max/K_m ratio for amikacin was higher than for the other aminoglycosides tested and PCR and DNA sequencing ruled out the presence of aph(3′)-IIps. Amikacin resistance in this strain was, therefore, associated with APH(3′)-VI and the high affinity of this enzyme for amikacin could explain the high-level resistance that we observed.     

Assessment and intervention for attention-deficit/hyperactivity disorder in the schools. Lessons from the MTA study

The MTA experience provides several lessons that may have clinical relevance. First, the MTA study identified six key instruments (see Table 1) that clinicians may want to use, but even on these instruments discrepancies in parent and teacher sources should be expected. We believe that unnoticed or unresolved discrepancies may be important factors contributing to the "disconnect" identified by the Consensus Conference Panel. Based on the MTA experience, we recommend a telephone call to the child's teacher, specifically to inquire about any discrepancy in the "source by domain" summary, as an efficient way to make a meaningful connection "... between developmental or educational (school-based) assessments and health-related (medical practice-based) services" for children with ADHD. Second, evaluation of pharmacologic intervention in the MTA study confirmed that teachers' reports are crucial for documenting efficacy, whereas parent reports are crucial for documenting side effects. Based on the MTA experience, we recommend frequent telephone contact with the teacher specifically to inquire about the peak effects and dissipation of effects of medication that are expected to occur during the school hours as a way to improve "... communication between diagnosticians and those who implement and monitor treatment in the schools."     

Variations in the low levels of cyclin D1/BCL1 have prognostic value in chronic lymphocytic leukemia

Cyclin D1 (CyD1)/BCL1 (PRAD1) is expressed at high levels in almost all cases of mantle cell leukemia/lymphoma (MCL) and in rare cases of chronic lymphocytic leukemia (CLL). The CyD1/BCL1 protein plays an important role in the progression of cells through the G1 phase of cell cycle. Most of the CyD1/BCL1 protein expression studies are performed using immunohistochemistry. We used a sensitive solid-phase radioimmunoassay (RIA) to quantify CyD1 protein expression in 199 patients with CLL. Of these 137 patients were previously untreated with the rest having had standard chemotherapeutic regimens including alkylating agents and fludarabine before being referred to our center. Median white cell count in these patients was 49x10(3) /microl (range 3.0-438.5x10(3)/microl), hemoglobin level 13.1 g/dl (range 5.2-17.3 g/dl), platelet count 157x10(3) /microl (range 10-377x10(3) /microl), age 58 (range 26-89), and beta2-microglobulin 2.75 mg/dl (range 1.1-14.3). The median radioactivity (CPM) of mononuclear cells obtained from 56 normal individuals was assigned a value of 1. There was no significant variation in CyD1 levels among normal individuals (SD=0. 12). While most CyD1 levels in MCL varied from 6.5 to 15.6, the median CyD1/BCL1 in CLL was 1.4 with 75th percentile under 2.12. Rare CLL cases (3.5%) showed levels between 4 and 8.83. When divided into two groups at the median level, patients with higher CyD1/BCL1 expression had shorter survival (P = 0.03). This remained true when applied only to the previously untreated patients (P=0.05). Despite the relatively low expression, the CyD1/BCL1 levels in univariate analysis were as good or better predictors of survival than Binet (P = 0.03) or Rai (P = 0.05) staging. Furthermore, CyD1/BCL1 levels correlated with serum beta2-microglobulin (P = 0.001), white blood cell count (P = 0.004) and hemoglobin levels at the time of collection (P = 0.0003) but not with lymphocyte count, platelet count or age. The data demonstrate that CyD1/BCL1 is likely to play a significant role in the biology of CLL and can be used as a prognostic indicator. Further studies to clarify the role of CyD1 in the biology of CLL and its value as a prognostic indicator at the time of diagnosis are encouraged.     

Role of pHyde novel gene product as an intrinsic factor for apoptotic pathway in prostate cancer

Induction of apoptotic cell death mechanism can be regulated by internal factor(s), such as by gene product(s) that directly upregulate the apoptosis pathway or indirectly by down-regulating the anti-apoptosis gene. This homeostasis is a normal phenomenon in a biological system disturbed by cancer. It is thus important to find any gene functioning as an upregulator for the apoptosis pathway that may have a potential application in the context of cancer gene therapy. We have cloned a novel rat gene, denoted as pHyde, that fulfilled this objective. Internally, this pHyde gene product renders the stable transfectant of rat prostatic cancer cell lines more susceptible to apoptosis even without any external inducer. By using an external agent, such as 5-fluoro-2'-deoxyuridine (FdUr), apoptotic responses of the stable transfectants are even higher, suggesting that both intrinsic and extrinsic factors work synergistically. The pHyde gene product was termed an intrinsic factor, whereas FdUr was considered an extrinsic factor for the apoptosis in rat prostate cancer model.     

Evaluation of individual subjects in the analog classroom setting: I. Examples of graphical and statistical procedures for within-subject ranking of responses to different delivery patterns of methylphenidate.

In this article, we describe graphical and statistical methods developed to evaluate the response patterns of individual children with attention deficit hyperactivity disorder (ADHD) to different conditions of treatment with stimulant medication. We used data from an investigation of drug delivery patterns to demonstrate these methods. Thirty-one children with ADHD participated in a double-blind crossover study of four conditions (three patterns of delivery of methylphenidate and a placebo control). In each condition, the children were evaluated across an 11-hour (7:00 a.m. to 6:00 p.m.) laboratory school day, and ratings of classroom behavior were obtained at regular intervals across the day. Graphical procedures were developed to display, for each individual, time courses of multiple measures of behavior taken across each double-blind test day. Expert clinicians judged these graphs and used this information to rank-order the test days from best to worst. A within-subject variant of Kendall's W was used to evaluate, for each subject, whether the rankings of these multidimensional graphs were reliable (concordant) across judges. A generalized kappa statistic was used to evaluate, for each condition, the reliability of the judges' rankings across subjects. Friedman's analysis of variance of ranks was used to evaluate, for the study, whether the conditions differed in terms of the average (consensus) rank assigned by the judges.     

The prognostic significance of tumor location and bowel obstruction in Dukes B and C colorectal cancer. Findings from the NSABP clinical trials.

The present study examines the prognostic significance of tumor location and bowel obstruction in Dukes B and C colorectal cancer. Data were obtained from 1021 patients entered into two randomized prospective clinical trials of the NSABP. Tumor location proved to be a strong prognostic discriminant. Lesions located in the left colon demonstrated the most favorable prognosis. Tumors of the rectosigmoid and rectum had the worst prognosis with the relative risk of treatment failure for the latter being over three fold that of the left colon. When the relative risks associated with tumor location were adjusted for nodal imbalances, the left colon continued to demonstrate the most favorable prognosis. The presence of bowel obstruction also strongly influenced the prognostic outcome. Examination of the data without considering tumor location disclosed that patients with bowel obstruction were at greater risk for treatment failure than those without obstruction. The effect of bowel obstruction was influenced by the location of the tumor. The occurrence of bowel obstruction in the right colon was associated with a significantly diminished disease-free survival, whereas obstruction in the left colon demonstrated no such effect. This phenomenon was independent of nodal status and tumor encirclement, the latter two factors proving to be of prognostic significance independent of tumor obstruction. A multivariate analysis in which the covariate effects of sex, age, nodal status, tumor obstruction, encirclement, and tumor location were adjusted underscored the role of tumor location and obstruction as prognostic discriminants. The results indicate that the definition of prognostic factors can identify patient subsets with unique characteristics.