DNA adducts, mutant frequencies and mutation spectra in lambda lacZ transgenic mice treated with N-nitrosodimethylamine

Groups of lambda lacZ transgenic mice were treated i.p. with N- nitrosodimethylamine (NDMA) as single doses of 5 mg/kg or 10 mg/kg or as 10 daily doses of 1 mg/kg and changes in DNA N7- or O6-methylguanine or the repair enzyme O6-alkylguanine-DNA alkyltransferase (AGT) were followed for up to 14 days in various tissues. Adduct induction in the liver exceeded by at least one order of magnitude than observed in the next nearest target tissue (lung), and was approximately linearly related to dose, except for O6-methylguanine after the first dose of 1 mg/kg which was lower than expected. Substantial induction of lambda lacZ mutagenesis was observed only in the liver, where the mutant frequency was already maximal within 7 days after 5 mg/kg NDMA and remained unchanged thereafter up to 49 days. Small but marginally significant increases in mutant frequency were consistently observed in the spleen after all three modes of treatment. A lack of proportionality between mutation induction and the administered dose or the corresponding adduct levels was observed, probably reflecting the importance of toxicity-related cell proliferation caused by NDMA at higher doses. Twenty eight days after a dose of 10 mg/kg (causing a 3.6- fold increase in mutant frequency), NDMA was found to increase the frequency of GC-->AT mutations (with a concomitant shift of their preferential location from CpG sites to GpG sites), which made up approximately 60% of the induced mutations. Surprisingly, NDMA also caused a significant increase in deletions of a few (up to 11) base- pairs (22%).      

Optimizing the Correlation between Results of Testing In Vitro and Therapeutic Outcome In Vivo for Fluconazole by Testing Critical Isolates in a Murine Model of Invasive Candidiasis

The trailing growth phenomenon seen when determining the susceptibilities of Candida isolates to the azole antifungal agents makes consistent endpoint determination difficult, and the M27-A method of the National Committee for Clinical Laboratory Standards addresses this problem by requiring an 80% reduction in growth after 48 h of incubation. For some isolates, however, minor variations of this endpoint criterion can produce up to 128-fold variations in the resulting MIC. To investigate the significance of this effect, isolates of Candida that exhibited various forms of trailing growth when tested against fluconazole were identified. The isolates were examined in a murine model of invasive candidiasis and were ranked by their relative response to fluconazole by using both improvement in survival and reduction in fungal burden in the kidney. The resulting rank order of in vivo response did not match the MICs obtained by using the M27-A criterion, and these MICs significantly overestimated the resistance of three of the six isolates tested. However, if the MIC was determined after 24 h of incubation and the endpoint required a less restrictive 50% reduction in growth, MICs which better matched the in vivo response pattern could be obtained. Minor variations in the M27-A endpoint criterion are thus required to optimize the in vitro-in vivo correlation for isolates that demonstrate significant trailing growth when tested against fluconazole.     

Thrombospondin promotes platelet aggregation

Thrombospondin (TSP), isolated from human platelets, promotes aggregation of both nonstimulated platelets and platelets stimulated with thrombin or ADP. The TSP-promoted aggregation is specific since a monoclonal antibody against TSP inhibits the effect of exogenously added TSP and inhibits thrombin-induced platelet aggregation in the absence of added TSP. Several lines of evidence suggest that TSP mediates its effect on aggregation of nonstimulated and stimulated platelets through different platelet-surface receptor systems. The TSP- promoted aggregation of nonstimulated platelets was inhibited by a monoclonal antibody to platelet glycoprotein IV (GPIV), but not by a monoclonal antibody to the fibrinogen receptor, GPIIb-IIIa. In contrast, the antibody to GPIIb-IIIa totally inhibited the TSP- potentiated aggregation of thrombin-stimulated platelets, whereas the antibody to GPIV has no effect. Thus, these studies suggest that TSP promotes platelet aggregation by at least two mechanisms--one dependent on and one independent of the platelet fibrinogen receptor system.     

Posttransplant T-cell lymphoproliferative disorders--an aggressive, late complication of solid-organ transplantation

T-cell non-Hodgkin's lymphomas are an uncommon occurrence after solid- organ transplantation. We describe a morphologically and immunophenotypically distinct group of T-cell lymphoproliferative disorders that occurred late in the course of six patients with solid- organ transplants. The patients ranged in age from 31 to 56 years (median, 43). Three were male; all were splenectomized. The interval from transplant to the diagnosis of lymphoma ranged from 4 to 26 years (median, 15). Symptoms at presentation were related to sites of involvement. Pulmonary, marrow, and CNS involvement were present in five, four, and one case, respectively. No patient had lymphadenopathy. Five patients had an elevated lactate dehydrogenase level (range, 226 to 4,880 IU/L; median, 1,220 IU/L). Five of six patients had a leukoerythroblastic reaction. All cases had large-cell histology and frequently contained cytoplasmic granules. Those cases tested expressed CD2, CD3, and CD8 and were negative for B-cell antigens. T-cell receptor beta- and gamma-chain genes were clonally rearranged in three of three and one of three cases, respectively. All T-cell posttransplant lymphoproliferative disorders (T-PTLDs) studied were negative for Epstein-Barr virus (EBV), human T-cell leukemia/lymphoma virus type 1 (HTLV-1), human T-cell leukemia/lymphoma virus type 2 (HTLV-2), and human herpes virus type 8 (HHV-8) genomes. Treatment with acyclovir (three patients) or chemotherapy (three patients) resulted in two responses. All patients had an aggressive course, with a median survival duration of 5 weeks. In conclusion, a clinically aggressive T- PTLD may be a late complication of solid-organ transplantation and does not appear to be related to EBV, HTLV-1, HTLV-2, or HHV-8 infection.     

Urinary nitrite excretion in premature infants: effects of transfusion or indomethacin

Urinary nitrite excretion, an index of L-arginine-dependent nitric oxide formation, was quantified daily for two weeks, in very low-birth-weight (< 1500 g) premature infants. A transient 52%) reduction in nitrite excretion was noted on the day of transfusions (54±10 versus 26±6 μmol/mmol creatinine, before and during transfusion, respectively, n = 24, p<0.02 ). Indomethacin administration in six infants was associated with a dramatic increase in nitrite excretion from a basal median value of 3 to 76 μmol/mmol creatinine (p<0.05). Nitrite excretion returned to baseline on day 3 after indomethacin administration. In two infants who received indomethacin and transfusions on the same day, the stimulatory effect on nitrite excretion by indomethacin overwhelmed any depressive effect of transfusions. These results suggest that L-arginine utilization is influenced by common therapeutic strategies in these high-risk infants.     

PGD12 Cost of Prescription Drugs and Cost of Treatment Failure for Sinusitis

A self-administered, disease-specific form of health status instrument for patients with COPD is not available in America. The St. George's Respiratory Questionnaire (SGRQ) is a successful measure in Great Britain and Europe that meets these requirements, but syntax and colloquial differences make an American version necessary.
OBJECTIVE: To test the validity and reliability of an American translation (ATSGRQ) of the SGRQ.
METHODS: Two bilingual health professionals independently translated the SGRQ based on summarized input from panels of American COPD patients and American respiratory professionals. Consensus was reached on the translated version and then back-translated by two other bilingual health professionals. To establish reliability, the ATSGRQ was given to COPD patients at the beginning of a pulmonary rehabilitation program (PRP) and repeated 1 week later. To establish validity, the ATSGRQ was used with pulmonary function tests, the Medical Research Council's dyspnea scale (DYS), 6-minute walk (6MW), and Short Form Health Status Profile-36 (SF-36) at the beginning and end of PRP for 24 COPD patients.
RESULTS: The patients were mean age 70 yr, 40% male, mean FEV1 = 0.95. The ATSGRQ Cronbach's alpha for overall scale and symptom, activity, and impact components was respectively .87, .65, .79, .80. Test-retest correlations were .70, .60, .72, .64, respectively. Baseline correlations between total ATSGRQ and FEV1, DYS, 6MW, and SF-36 physical and mental health component scores were −.43, 54, .56, −.76, −.62. From initial to post-PRP, the symptom ATSGRQ decreased 12.6% (p = .004); DYS decreased 10.6% (p = .043).
CONCLUSION: Based on these preliminary data, the ATSGRQ appears to be a valid, reliable health status instrument for use in an American COPD population.     

Correlation between microdilution, E-test, and disk diffusion methods for antifungal susceptibility testing of posaconazole against Candida spp

Agar-based antifungal susceptibility testing is an attractive alternative to the microdilution method. We examined the correlation between the microdilution, E-test, and disk diffusion methods for posaconazole against Candida spp. A total of 270 bloodstream isolates of Candida spp. with a broad range of posaconazole MICs were tested using the CLSI M27-A2 method for microdilution, as well as the M-44A method and E-test methods for agar-based testing on Mueller-Hinton agar supplemented with 2% glucose and 0.5 microg of methylene blue. MICs and inhibitory zone diameters at the prominent growth reduction endpoint were recorded at 24 and 48 h. The Candida isolates included Candida albicans (n = 124), C. parapsilosis (n = 44), C. tropicalis (n = 41), C. glabrata (n = 36), C. krusei (n = 20), C. lusitaniae (n = 3), and C. dubliniensis (n = 2). The overall concordance (i.e., the percentage of isolates within two dilutions) between the E-test and microdilution was 64.8% at 24 h and 82.6% at 48 h. When we considered an arbitrary breakpoint of < or = 1 microg/ml, the agreement between the E-test and microdilution methods was 87.8% at 24 h and 93.0% at 48 h. The correlation of MICs with disk diffusion zone diameters was better for the E-test than the microdilution method. Zone correlation for diameters produced by the disks of two manufacturers was high, with a Pearson test value of 0.941 at 24 h. The E-test and microdilution MICs show good concordance and interpretative agreement. The disk diffusion zone diameters are highly reproducible and correlate well with both the E-test and the microdilution method, making agar-based methods a viable alternative to microdilution for posaconazole susceptibility testing.     

Routine CT screening of psychiatry inpatients

During a 3-year period, all inpatients in the psychiatry unit underwent routine screening computed tomography (CT) in an effort to detect clinically unsuspected intracranial abnormalities. Of 261 patients examined who had no focal neurologic deficits, 103 had schizophrenia, 71 had depression, 48 had bipolar disorders, and 39 had paranoid delusions. Findings on 230 (88.1%) of the CT scans were within normal limits, and 27 (10.4%) showed only cortical atrophy. The remaining four cases (1.5%) demonstrated basal ganglia calcification (n = 2), old lacunar infarction (n = 1), or osteoma arising from the inner table of the skull (n = 1), all of which were considered to be clinically unrelated to the patients' psychiatric conditions. In the absence of focal neurologic deficits or other findings suggesting an intracranial abnormality (eg, papilledema, seizures, persistent or increasing headaches), there is no justification for routine CT scanning in patients admitted to the hospital for psychiatric disorders.     

Prognostic significance of argyrophilic nucleolar organizer region (AgNOR) in resected non-small cell lung cancer (NSCLC)

The expression of the nucleolar organizer regions (NORs) was quantified in paraffin sections of tumors and lymph node metastasis, by means of digital image analysis, in 75 patients with resected non-small cell lung cancer (NSCLC). Patients were divided in two groups: early stage (stages I and II) and advanced stage (stages IIIa, IIIb and IV). The prognostic significance of AgNOR expression was tested by Cox regression analysis in models controlled for age, sex, vital status, stage and histological type. Tumors at early stages had a lower expression of AgNOR than those at more advanced diseases. The mean values obtained for NORs in advanced disease were almost the same as those in the primary tumors when compared with the corresponding lymph node metastasis (r = 0.90; p < 0.01; linear regression). The prognostic role of AgNOR was significant only for tumors at stages I and II and not for advanced neoplasms (stages IIIa, IIIb and IV). These results encourage the inclusion of AgNOR quantitation in routine material, especially in early lung cancer.      

Morphine pharmacokinetics in premature and mature newborn infants

The pharmacokinetics of a single dose of morphine was investigated in five term infants (gestational age 37–40 weeks) and eight preterm infants (gestational age 25–32 weeks). In the five term infants, median (range) volume of distribution at steady state (Vd_β) was 1758 (634–2700) ml/kg, plasma clearance (Cl) was 4.73 (1–75–6.61) ml/kg/min and terminal half-life (T1/2) was 224 (107–394) min. In the eight preterm infants, Vd_β was 2366 (1662–2876) ml/kg, Cl was 2.82 (1.88–6.60) ml/kg/min and T1/2 was 556 (248–834) min. No correlation was found between clearance and gestational age, but we found a significant negative correlation between T1/2 and gestational age. We conclude that there is considerable variation in the pharmacokinetic properties of morphine in both term and preterm newborn infants. Because of this variation, careful individual assessment of the clinical effect of therapy with morphine in newborn infants should be exercised.