Newer methods of labeling diagnostic agents with Tc-99m

The past several years have seen marked advances in technetium/rhenium chemistry applicable to the preparation of new 99mTc-labeled radiopharmaceuticals. This article focuses on recent developments in technetium chemistry, including the preparation of "3 + 1" complexes, the preparation and use of (99mTc[CO]3)+ complexes for labeling biomolecules, the preparation of rhenium steroid inclusion complexes, improvements in both hydrazinonicotinamide labeling chemistry and in the preformed 99mTc complex method of labeling biomolecules, and new solid-phase separation techniques that may allow the isolation of high specific-activity radiopharmaceuticals in a clinical setting.

Cardioprotective effects of ramipril and losartan in right ventricular pressure overload in the rabbit: importance of kinins and influence on angiotensin II type 1 receptor signaling pathway

BACKGROUND

The role of kinins in the cardioprotective effects of ACE inhibitors remains controversial.

METHODS AND RESULTS

Right ventricular pressure overload in rabbits was produced by pulmonary artery banding for 21 days. Rabbits were untreated, or they received the ACE inhibitor ramipril with or without bradykinin B(1) and B(2) receptor blockers or the angiotensin (Ang) II type I (AT(1)) receptor blocker losartan. Pulmonary artery banding caused right ventricular hypertrophy, depressed papillary muscle contractility, and loss of Ang II contractile effects because of a signaling defect downstream of AT(1) receptors. Paradoxically, AT(1) receptor density and G protein alpha subunits alphaq and alphai1/2 increased. Inotropic responsiveness to the alpha-receptor agonist phenylephrine was normal. Ramipril preserved cardiac contractility, but this effect was attenuated by simultaneous use of kinin receptor blockers. Ramipril also maintained responsiveness to Ang II and prevented AT(1) receptor and G protein upregulation. The simultaneous use of a kinin receptor blocker attenuated but did not prevent upregulation in the AT(1) receptor and G protein. Losartan had no effect on baseline contractility, but it maintained cardiac inotropic responsiveness to Ang II, prevented upregulation of AT(1) receptors, but did not modify G protein upregulation.

CONCLUSIONS

Pressure overload of the right ventricle decreases contractility, uncouples AT(1) receptors to downstream signaling pathways, and changes the expression of components of the AT(1) receptor signaling pathway. Ramipril attenuates these effects via kinins. Interventions that prevent local increases in Ang II or block AT(1) receptors also prevent decreased responsiveness of the AT(1) receptor in this model.

Synthesis, mechanism of action, and antiviral activity of a new series of covalent mechanism-based inhibitors of S-adenosyl-L-homocysteine hydrolase

A direct method for the preparation of 5'-S-alkynyl-5'-thioadenosine and 5'-S-allenyl-5'-thioadenosine has been developed. Treatment of a protected 5'-acetylthio-5'-deoxyadenosine with sodium methoxide and propargyl bromide followed by deprotection gave the 5'-S-propargyl-5'-thioadenosine 4. Under controlled base-catalysis with sodium tert-butoxide in tert-butyl alcohol 4 was quantitatively converted into 5'-S-allenyl-5'-thioadenosine 5 or 5'-S-propynyl-5'-thioadenosine 6. Incubation of recombinant human placental AdoHcy hydrolase with 4, 5, or 6 resulted in time- and concentration-dependent inactivation of the enzyme (K(i): 45 +/- 0.5, 16 +/- 1, and 15 +/- 1 microM, respectively). Compound 4 caused complete conversion of the enzyme from its E-NAD(+) to E-NADH form during the inactivation process. This indicates that 4 is a substrate for the 3'-oxidative activity of AdoHcy hydrolase (type I inhibitor). In contrast, the NAD(+)/NADH content of the enzyme was not affected during the inactivation process with 5 and 6, and their mechanism of inactivation was further investigated. Addition of enzyme-sequestered water on the S-allenylthio group of 5 or S-propynylthio group of 6 within the active site should lead to the formation of the corresponding thioester 7. This acylating-intermediate agent could then undergo nucleophilic attack by a protein residue, leading to a type II mechanism-based inactivation. ElectroSpray mass spectra analysis of the inactivated protein by 5 supports this mechanistic proposal. Further studies (MALDI-TOF and ESI/MS(n) experiments) of the trypsin and endo-Lys-C proteolytic cleavage of the fragments of inactivated AdoHcy hydrolase by 5 were carried out for localization of the labeling. The antiviral activity of 4, 5, and 6 against a large variety of viruses was determined. Significant activity (EC(50): 1.9 microM) was noted with 5 against vaccinia virus.

Dual topology of the hepatitis B virus large envelope protein: determinants influencing post-translational pre-S translocation

The large (L) envelope protein of the hepatitis B virus (HBV) has the peculiar capacity to form two transmembrane topologies via an as yet uncharacterized process of partial post-translational translocation of its pre-S domain across membranes. In view of a current model that predicts an HBV-specific channel generated during virion envelope assembly to enable pre-S translocation, we have examined parameters influencing L topogenesis by using protease protection analysis of wild-type and mutant L proteins synthesized in transfected cells. We demonstrate that contrary to expectation, all determinants, thought to be responsible for channel formation, are dispensable for pre-S reorientation. In particular, we observed that this process does not require (i) the helper function of the HBV S (small) and M (middle) envelope proteins, (ii) covalent dimer formation of envelope chains, or (iii) either of the three amphipathic transmembrane segments of L. Rather, the most hydrophobic transmembrane segment 2 of L was identified as a vital topogenic determinant, essential and sufficient for post-translational pre-S translocation. Cell fractionation studies revealed that pre-S refolding and thus the dual topology of L is established at the endoplasmic reticulum (ER) membrane rather than at a post-ER compartment as originally supposed. Together our data provide evidence to suggest that the topological reorientation of L is facilitated by a host cell transmembrane transport machinery such as the ER translocon.

Toxicity to Bivalve Hemocytes of Pathogenic Vibrio Cytoplasmic Extract

Using a chemiluminescence (CL) test, it had been previously demonstrated that Vibrio pectenicida, which is pathogenic to Pecten maximus larvae, was able to inhibit completely the CL activity of P. maximus hemocytes and partially inhibit those of Crassostrea gigas. Conversely, a Vibrio sp. strain, S322, pathogenic to C. gigas larvae was more active in reducing the CL activity of oyster hemocytes than of scallop hemocytes. Using this same CL biotest, V. pectenicida and S322 cytoplasmic extracts were shown to reproduce CL inhibition while the cytoplasmic extract of a nonpathogenic strain (U1, Pseudoalteromonas) was without effect. Moreover, cytoplasmic extract as well as live V. pectenicida cells provoked, within a few hours, death of P. maximus hemocytes adhering to a glass slide. After partial purification, it was shown that toxic activities of V. pectenicida cytoplasmic extract was due to a toxin, named VHKT (for vibrio hemocyte-killer toxin), which is heat stable, acid and protease resistant, and less than 3 kDa in molecular weight. Attempts to purify VHKT by reverse-phase (C18) HPLC separated activity into the fraction eluted by water at a retention time of 4.02 min.

Variant human immunodeficiency virus type 1 proteases and response to combination therapy including a protease inhibitor

The objective of this observational study was to assess the genetic variability in the human immunodeficiency virus (HIV) protease gene from HIV type 1 (HIV-1)-positive (clade B), protease inhibitor-naïve patients and to evaluate its association with the subsequent effectiveness of a protease inhibitor-containing triple-drug regimen. The protease gene was sequenced from plasma-derived virus from 116 protease inhibitor-naïve patients. The virological response to a triple-drug regimen containing indinavir, ritonavir, or saquinavir was evaluated every 3 months for as long as 2 years (n = 40). A total of 36 different amino acid substitutions compared to the reference sequence (HIV-1 HXB2) were detected. No substitutions at the active site similar to the primary resistance mutations were found. The most frequent substitutions (prevalence, >10%) at baseline were located at codons 15, 13, 12, 62, 36, 64, 41, 35, 3, 93, 77, 63, and 37 (in ascending order of frequency). The mean number of polymorphisms was 4.2. A relatively poorer response to therapy was associated with a high number of baseline polymorphisms and, to a lesser extent, with the presence of I93L at baseline in comparison with the wild-type virus. A71V/T was slightly associated with a poorer response to first-line ritonavir-based therapy. In summary, within clade B viruses, protease gene natural polymorphisms are common. There is evidence suggesting that treatment response is associated with this genetic background, but most of the specific contributors could not be firmly identified. I93L, occurring in about 30% of untreated patients, may play a role, as A71V/T possibly does in ritonavir-treated patients.

CD4+ and CD8+ clonal T cell expansions indicate a role of antigens in ankylosing spondylitis; a study in HLA-B27+ monozygotic twins

Ankylosing spondylitis (AS) is a complex genetic disease in which both MHC and non-MHC genes determine disease susceptibility. To determine whether the T cell repertoires of individuals with AS show signs of increased stimulation by exogenous antigens, CD4+ and CD8+ T cell subsets of five monozygotic HLA-B27+ twins (two concordant and three discordant for AS) and CD8+ T cell repertoires of three healthy HLA-B27+ individuals were characterized by TCR beta-chain (TCRB) CDR3 size spectratyping. Selected TCRB-CDR3 spectra were further analysed by BJ-segment analysis and TCRB-CDR3 from expanded T cell clones were sequenced. In an analysis of all data (519/598 possible TCRB-CDR3 spectra), AS was associated with increased T cell oligoclonality in both CD8+ (P = 0.0001) and CD4+ (P = 0.033) T cell subsets. This was also evident when data were compared between individual twins. Nucleotide sequence analysis of expanded CD8+ or CD4+ T cell clones did not show selection for particular TCRB-CDR3 amino acid sequence motifs but displayed sequence homologies with published sequences from intra-epithelial lymphocytes or synovial T cells from rheumatoid arthritis patients. Together, these results provide support for the hypothesis that responses to T cell-stimulating exogenous or endogenous antigens are involved in the induction and/or maintenance of AS.

Comparison of DNA sequencing and a line probe assay for detection of human immunodeficiency virus type 1 drug resistance mutations in patients failing highly active antiretroviral therapy

The resistance of human immunodeficiency virus type 1 (HIV-1) to drugs is a major cause of antiretroviral treatment failure. We have compared direct sequencing to a line probe assay (LiPA) for the detection of drug resistance-related mutations in 197 clinical samples, and we have investigated the sequential appearance of mutations under drug pressure. For 26 patients with virological failure despite the use of two nucleoside analogues and one protease inhibitor (indinavir [n = 6], ritonavir [n = 10], and saquinavir [n = 10]), genotypic resistance assays were carried out retrospectively every 3 months for up to 2 years by using direct sequencing (TruGene; Visible Genetics) and a LiPA for detection of mutations in the reverse transcriptase (INNO-LiPA HIV-1 RT; Innogenetics) and the protease (INNO-LiPA HIV Protease, prototype version; Innogenetics) genes. Comparison of the results from both assays found rare major discrepancies (<1% of codons analyzed). INNO-LiPA detected more wild-type-mutant mixtures than sequencing but suffered from a high rate of codon hybridization failures for the reverse transcriptase. LiPA detected earlier and more frequently than sequencing the transient mixed virus population that contained I84V, which appears before V82A in the protease sequence. Mutations M461, G48V, and L90M were often transient and drug pressure related. In conclusion, direct sequencing and LiPAs give concordant results for most clinical isolates. LiPAs are more sensitive for the detection of mixed virus populations. Mutation I84V appears in minor populations in the early steps of the pathways of resistance to indinavir and ritonavir. The fact that some mutations can be found only transiently and in minor virus populations highlights the importance of a low detection limit for resistance assays.

The expression of G250/mn/CA9 antigen by flow cytometry: its possible implication for detection of micrometastatic renal cancer cells

Monoclonal antibody (mAb) G250 is a well characterized and specific mAb to renal cell carcinoma (RCC). The gene G250 was recently cloned and was proved to be homologous to MN/CA9. The G250/MN/CA9 antigen was recently explored as a potential marker for RCC. Flow cytometry (FCM) allows quantitative analysis of cells. The present study describes a flow cytometric method to detect this antigen in human cell lines and in malignant and normal renal tissues. Twelve human carcinoma cell lines (HeLa, Colo205, HT29, BxPC3, OVCAR3, SKOV3, ACHN, A704, CAKI-2, SKRC-59, SKRC-10, and SKRC-52), 10 specimens of normal peripheral blood mononuclear cells, and 38 malignant and 36 adjacent normal renal tissues were studied. The malignant and normal renal tissues were disaggregated mechanically into a single-cell suspension, stained by mAb G250, and analyzed by FCM. All 22 of the clear cell carcinomas, 6 of 8 mixed cell carcinomas, and 3 of 6 granular cell carcinomas were positive for G250/MN/CA9 antigen. SKRC-52 and SKRC-10 were strongly positive for G250/ MN/CA9. The G250/MN/CA9 antigen could also be detected in HeLa, SKOV3, HT29, and A704 cells. One chromophobic, one chromophilic cell carcinoma, the normal renal tissues, and normal peripheral blood mononuclear cells were considered as negative. Our results further confirmed that the G250/MN/CA9 antigen was an ideal marker for RCC, especially for clear cell carcinomas, and that this antigen was present in several types of malignant cells. FCM may serve as a fast tool of immunocytochemical detection of renal cancer cells. Flow cytometric detection of renal cancer cells by using mAb G250 should be further explored.

First hemodialysis access selection varies with patient acuity

Timely placement of a reliable permanent vascular access is essential for hemodialysis care quality; National Kidney Foundation Dialysis Outcomes Quality Improvement (NKF-DOQI) guidelines emphasize native arterio-venous (AV) fistulae as preferred access for incident patients. As part of Network One's Vascular Access Quality Improvement Project (QIP) we investigated whether patients' course to end-stage renal disease (ESRD) influenced vascular access selection. Baseline information was obtained for incident (1998) dialysis patients from 6 centers participating in the Network QIP. Patients were subdivided into 3 predefined clinical groups: KNOWN (known chronic renal disease, seen by a nephrologist, with predictable progression to ESRD), CRISIS (KNOWN but with unanticipated medical crisis precipitating ESRD), and UNKNOWN (not known to have chronic renal insufficiency or never seen by a nephrologist before developing ESRD). Two hundred forty patients were identified (median age 69.9, 42% diabetic). Only 43% of the entire population experienced an orderly progression to renal insufficiency. The most frequent initial access was a catheter (54%), followed by a fistula (29%) and a graft (16%), but selection of initial access differed significantly by patient group, with 46% of KNOWN patients receiving a fistula (P <.001). After 2 months of dialysis, the initial access supported dialysis in only 53.7% of the KNOWN patients, and in 59.4% and 45.7% of the CRISIS and UNKNOWN patients, respectively. We conclude that unpredicted, new ESRD patients are common and are less likely to receive a fistula as initial hemodialysis access. Studies should define optimum access management when dialysis requirement is unforeseen.

Three-year effectiveness of highly active antiretroviral treatment in the Luxembourg HIV cohort

Clinical trials have shown that highly active antiretroviral treatment (HAART) is able to reduce HIV plasma viral loads to undetectable in 70% to 90% of patients and to increase CD4 cell counts. HAART in community settings (i.e., nonclinical trial situations) is reported to be much less effective.

STUDY DESIGN

Observational study.

PURPOSE

The aim of our study was to evaluate the effectiveness of protease inhibitor (PI)-based HAART in the Luxembourg HIV cohort after 36 months of treatment in previously treated and untreated patients. The secondary aim was to identify surrogate markers associated with long-term virologic and immunologic outcomes.

PATIENTS AND METHOD

Seventy-three PI-naive patients, who started on HAART, combining one PI and two nucleoside reverse transcriptase inhibitors (NRTIs),with a follow-up of 3 years, were evaluated with plasma viral load and CD4 cell counts every 3 months and were analyzed retrospectively. Patients who had been treated previously with NRTI (n = 48) were at a more advanced stage of disease.

RESULTS

Overall, there was a mean decrease in viral load compared to baseline of -1.89 log RNA copies/mL (SD = 1.40) that persisted at month 36. Sixty-two percent (62%) of patients reached an undetectable viral load (i.e., below 500 copies/mL): 82% and 53% of NRTI-naive and NRTI-experienced patients, respectively (p =.013). CD4 cell counts increased progressively in both groups with a sustained effect (mean increase of 146 cells/mL +/- 241) at month 36. NRTI-naive patients had a mean increase of 257 cells/mL (SD = 305), in contrast to experienced patients who had an increase of 108 cells/mL (SD = 206) at 3 years. Proportions of patients with a CD4 count under 200 cells/mL fell after 3 years for NRTI-naive (from 66% to 43%) and for experienced patients (from 32% to 13%). Predictors of short duration of viral load response were in decreasing order of importance: clinical AIDS, the use of saquinavir hard gel formulation as initial PI, and the number of NRTIs previously used. Viral load response was the only significant predictor of CD4 changes.

CONCLUSION

In a community setting, effectiveness of PI-based HAART at 3 years is still achieved for most patients. NRTI-experienced patients have a good long-term response rate even if it is lower than NRTI-naive patients. A poor treatment response is associated with a more advanced stage of disease before HAART is introduced.

Outcome data on pediatric dialysis patients from the end-stage renal disease clinical indicators project

Network 1 (New England) initiated the Clinical Indicator Project to survey dialysis adequacy (Kt/V), nutrition (serum albumin level), and anemia management in patients maintained on chronic dialysis. Because little information is available in children, data were specifically recorded covering these variables in patients (age, 1 to 18 years) maintained on either hemodialysis (HD) or peritoneal dialysis (PD). During the 18 months of data collection, 29 observations were recorded on 23 HD patients (age, 14.3 +/- 3.6 years), and 43 observations were made on 30 PD patients (age,10.6 +/- 4.7 years). Kt/V correlated inversely with the age of the patient (HD, P < 0.004; PD, P < 0.0007). Although serum albumin level was not associated with dialysis adequacy in HD patients, there was a strong inverse relationship between albumin level and Kt/V in PD patients (P < 0.002). Hematocrit values were not significantly different in the two groups (HD, 31.0% +/- 5.5% versus PD, 32.9% +/- 4.8%) and could not be correlated with weekly erythropoietin dose. Weekly erythropoietin dose was directly related to patient age in both groups (HD, P < 0.05; PD, P < 0.02). The weekly erythropoietin dosage needed to maintain the hematocrit was greater in HD patients (HD, 11,211 +/- 7,484 U versus PD, 3,790 +/- 1,968 U; P < 0.0001). We conclude that (1) smaller children in both groups tend to have a greater Kt/V, (2) Kt/V greater than 2.75 in PD patients may not improve nutrition per se and could result in increased albumin losses, and (3) erythropoietin dosing appears to correlate best with patient size (age) rather than degree of anemia.

Serum and ascitic procalcitonin levels in cirrhotic patients with spontaneous bacterial peritonitis: diagnostic value and relationship to pro-inflammatory cytokines

OBJECTIVE

To assess the potential role of procalcitonin and pro-inflammatory cytokines, TNF-alpha, and IL-6, in the diagnosis of spontaneous bacterial peritonitis (SBP).

DESIGN

Prospective study.

SETTING

The emergency unit of a teaching hospital.

PATIENTS

We included 21 patients with SBP and 40 patients with sterile ascitic fluid.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

For the diagnosis of SBP, the best markers were serum levels of procalcitonin with a cut-off value of 0.75 ng/ml, a sensitivity of 95%, a specificity of 98%, and ascitic fluid levels of IL-6 with a cut-off value of 5,000 ng/ml, a sensitivity of 100%, and a specificity of 88%. C-reactive protein and serum polymorphonuclear count have low sensitivity/specificity at 62/92% and 57/90%, respectively. From 21 patients with SBP, ascitic fluid to serum ratio of TNF-alpha and IL-6 was greater than to 2 in all cases with a mean at 6.2 +/- 6.5 and 34 +/- 31, respectively. By contrast, this ratio for procalcitonin was less than 1 in all cases with a mean at 0.31 +/- 0.25. We found no correlation between procalcitonin levels and cytokine levels in either ascitic fluid or serum.

CONCLUSIONS

Serum procalcitonin level may become a useful marker for the diagnosis of SBP in cirrhotic patients. The low ratio of ascitic fluid to serum procalcitonin supports the hypothesis that procalcitonin is not produced intraperitoneally.

Sleep and circadian phase characteristics of adolescent and young adult males in a naturalistic summertime condition

Our aim was to compare the circadian phase characteristics of healthy adolescent and young adult males in a naturalistic summertime condition. A total of 19 adolescents (mean age 15.7 years) and 18 young adults (mean age 24.5 years) with no sleep problems took part in this study. Two-night polysomnographic (PSG) sleep recordings and 24h secretion patterns of urinary 6-sulfatoxymelatonin were monitored in all 37 subjects. Sleep-wake patterns were initially assessed at home using a standard sleep diary. Circadian assessment included the measure of dim light melatonin offset (DLMOff) and the morningness-eveningness (M/E) questionnaire. As expected, compared to young adults, adolescents habitually spent more nocturnal time in bed and spent more time (and percentage) in delta sleep. No difference was found between adolescents and young adults on multiple sleep latency test (MSLT) sleep onset latencies, M/E, melatonin secretion measures (24h total, nighttime, daytime, and night ratio), and DLMOff. For the subjects as a whole, correlational analyses revealed a significant association between the DLMOff and M/E and between both these phase markers and habitual bedtimes, habitual rising times, and melatonin secretion measures (daytime levels and the night ratio). No association was found between phase markers and daytime sleepiness or sleep consolidation parameters such as sleep efficiency or number of microarousals. These results together indicate that adolescents and young adults investigated during summertime showed similar circadian phase characteristics, and that, in these age groups, an evening phase preference is associated with a delayed melatonin secretion pattern and delayed habitual sleep patterns without a decrease in sleep consolidation or vigilance.

Residual renal function in a large cohort of peritoneal dialysis patients: change over time, impact on mortality and nutrition

OBJECTIVE

Residual renal function contributes importantly to total solute clearance in peritoneal dialysis (PD) patients. This study was designed to examine the progression of residual renal function over time and its impact on nutrition and mortality in PD patients in the six New England states (ME, NH, VT, CT, MA, RI) comprising End Stage Renal Disease (ESRD) Network 1.

DESIGN

As part of the ESRD Clinical Indicators Project, data on 990 PD patients in Network 1 were abstracted from data supplied by dialysis units in the fourth quarter of 1997. This included demographic information; dose of PD in L/day; weekly renal, dialysis, and total Kt/V urea; weekly renal, dialysis, and total creatinine clearance (CCr); serum albumin level; and mortality and transplantation information. Data collection was repeated in the second and fourth quarters of 1998 and in the second quarter of 1999.

PATIENTS

990 PD patients in Network 1.

OUTCOME MEASURES

The change in total and renal solute clearances over time, the relationship between renal clearance and mortality, and the relationship between renal clearance and nutritional status, as represented by serum albumin.

RESULTS

Over the 2-year period, mean weekly renal Kt/V urea and weekly renal CCr dropped significantly. To examine the effect of residual renal function on mortality, patients were divided into high and low (above and below the median) weekly renal Kt/V urea and weekly renal CCr groups. Patients above the median levels of both weekly renal Kt/V urea and weekly renal CCr had a significantly decreased risk of dying during the observation period, after controlling for age, gender, serum albumin level, and diabetic status [OR for high vs low renal Kt/V urea 0.54 (CI 0.34 - 0.84), OR for high vs low renal CCr 0.61 (CI 0.40 - 0.94)]. The mean weekly renal Kt/V urea was significantly and directly correlated with the mean serum albumin level by Spearman rank correlation (R = 0.133, p < 0.001), as was the mean weekly renal CCr (R = 0.115, p < 0.001).

CONCLUSIONS

Residual renal function is an important contributor to total solute clearance in PD patients. Even at low levels it is linked to decreased mortality and better nutritional status.

Flow cytometric analysis of antigen expression in malignant and normal renal cells

Flow cytometry allows quantitative analysis of cancer cells. The aim of this study was to make a quantitative study of antigen expression in malignant and normal renal cells in order to find the efficient monoclonal antibodies (mAbs) for labelling renal cancer cells.

MATERIAL AND METHODS

15 malignant and adjacent normal renal tissues and three renal carcinoma cell lines (ACHN, A704 and CAKI-2) were analyzed. The malignant and normal renal tissues were dissociated mechanically into cell suspension. The mAbs and isotype controls were used for immunochemical labelling. The stained cells were analyzed by flow cytometry.

RESULTS

Renal tumor associated antigen G 250 was frequently detected in malignant renal cells but not in normal renal cells. Renal tumor associated antigen gp200 recognized by 66.4.C2 and PN-15 was frequently detected in malignant cells, normal renal cells and also in all three carcinoma cell lines. Epithelial antigens were strongly positive in normal renal cells. Compared with MOC 31, Ber-EP4 and E 29, W-lD9 was mostly reactive to malignant renal cells. VU-1D9 was strongly positive on ACHN and A704. The carbohydrate carcinoma antigens CA 125, DF3 and Sialyl Lewis(a) were detectable in some of the malignant and normal renal cells. Sialyl Lewis(a) could be weakly detected on ACHN and A 704. Pan-cytokeratins and cytokeratin (CK) 8 were strongly expressed in malignant and normal renal cells and in all three cell lines.

CONCLUSION

Our results indicated that G 250, 66.4.Ca, PN-15, VU-1D9, MNF116 and anti-ckg were efficient mAbs for labelling renal cancer cells. Their potential clinical application by flow cytometry should be explored.

In vitro and in vivo effects of kinin B(1) and B(2) receptor agonists and antagonists in inbred control and cardiomyopathic hamsters

The aims of this study were to examine the possible alterations occurring in the effects of kinins on isolated aortae of inbred control (CHF 148) and cardiomyopathic (CHF 146) hamsters of 150 - 175 and 350 - 375 days of age. Bradykinin (BK) and desArg(9)BK contracted isolated aortae (with or without endothelium) of hamsters of both strains and ages. After tissue equilibration (90 min), responses elicited by both kinin agonists were stable over the time of experiments. The patterns of isometric contractions of BK and desArg(9)BK were however found to be different; desArg(9)BK had a slower onset and a longer duration of action than BK. Potencies (pEC(50) values) of BK in all groups of hamsters were significantly increased by preincubating the tissues with captopril (10(-5) M). No differences in the pEC(50) values and the E(max) values for BK or desArg(9)BK were seen between isolated vessels from inbred control and cardiomyopathic hamsters. The myotropic effect of BK was inhibited by the selective non peptide antagonist, FR 173657 (pIC(50) 7.25+/-0.12 at the bradykinin B(2) receptor subtype (B(2) receptor)). Those of desArg(9)BK, at the bradykinin B(1) receptor subtype (B(1) receptor) were abolished by either R 715 (pIC(50) of 7. 55+/-0.05; alpha(E) = 0), Lys[Leu(8)]desArg(9)BK (pIC(50) of 7.21+/-0. 01; alpha(E) = 0.22) or [Leu(8)]desArg(9)BK (pIC(50) of 7.25+/-0.02; alpha(E) = 0.18). FR 173657 had no agonistic activity, exerted a non competitive type of antagonism and was poorly reversible (lasting more than 5 h) from B(2) receptor. In vivo, FR 173657 (given per os at 1 and 5 mg kg(-1), 1 h before the experiment) antagonized the acute hypotensive effect of BK in anaesthetized hamsters. It is concluded that aging and/or the presence of a congenital cardiovascular disorder in hamsters are not associated with changes in the in vitro aortic responses to either BK or desArg(9)BK.

[Rapid diagnosis of the type of meningitis (bacterial or viral) by the assay of serum procalcitonin]

OBJECTIVE

It has been shown that serum procalcitonin (PCT) can be used to differentiate bacterial from viral meningitis in children in all cases. The aim of this study was to demonstrate the interest of PCT in the management of suspected meningitis in adults.

PATIENTS AND METHODS

We conducted a prospective study including 179 consecutive patients admitted to the emergency department for suspected meningitis. All samples were taken at patient admission. The discriminant potential between bacterial and viral meningitis was studied for cerebrospinal fluid parameters (cytology, protein, glucose, lactate) and serum parameters (C reactive protein, PCT).

RESULTS

Thirty-two patients had bacterial meningitis, 90 had viral meningitis and meningitis was ruled out in 57. Among all studied parameters, the most discriminant for distinguishing between bacterial and viral meningitis in 100% of the cases proved to be serum procalcitonin with a threshold value of 0.93 ng/ml.

CONCLUSION

Serum procalcitonin is an interesting parameter in the emergency department for management of meningitis suspicion in adults.

Decreased production of local immunoglobulin A to Pneumocystis carinii in bronchoalveolar lavage fluid from human immunodeficiency virus-positive patients

An enzyme-linked immunosorbent assay and a Western blot analysis were developed to study the antibody response to Pneumocystis carinii in serum and bronchoalveolar lavage fluid from 27 human immunodeficiency virus 27 (HIV)-infected patients with P. carinii pneumonia (Pcp), 32 patients without Pcp, and 51 HIV-negative controls. Urea was used for the correct dilution of epithelial lining fluid, and albumin was used to evaluate transudation from plasma for the assessment of local production of antibodies to P. carinii. By contrast with those of immunoglobulin G (IgG), IgA responses to P. carinii were increased in serum from HIV-positive patients compared to negative controls. Local production of antibodies to P. carinii, especially IgA, was decreased in patients with Pcp. In a study of 10 patients of each group, IgG and IgA responses to gp116 from P. carinii were lower in patients with Pcp than in other groups. These results suggest that, in addition to alveolar macrophages, local antibodies may play a role in host defense against P. carinii.

Expression of PGP9.5 on Langerhans' cells and their precursors

Langerhans' cells are epidermal dendritic cells, derived from blood precursors. Their main function is antigen presentation to T-cells. They are able to express neuronal proteins, such as neuron-specific enolase or substance P-receptor. They are closely associated with nerve fibres. PGP9.5 is the most specific neuronal protein in the epidermis. Epidermal Langerhans' cells can express PGP9.5 if denervated. Using flow cytometry, we found that cultured CD34+ precursors did not express PGP9.5, whereas suspensions of fresh or cultured Langerhans' cells could express this neuronal protein. Precursors of Langerhans' cells are not able to express PGP9.5, suggesting that they are not mature enough or that the capacity to express PGP9.5 may be acquired only in the epidermis. The function of PGP9.5 on Langerhans' cells and mature dendritic cells remains unknown. PGP9.5 might be related to dendritic cell maturation or to the lack of contacts with nerve endings.

Association between melatonin secretion and daytime sleep complaints in night nurses

STUDY OBJECTIVES

To test the hypothesis that nightworkers' diurnal sleep complaints are associated with the timing of melatonin secretion.

DESIGN

After a minimum of three consecutive night shifts, the subjects were admitted to the laboratory for 24 hours during which they were allowed to eat and sleep ad lib. Urine was collected every two hours under dim illumination (<25 lux). Concentration of urinary 6-sulphatoxymelatonin (UaMT6s) was determined by radioimmunoassay. Sleep quality was assessed by questionnaires.

SETTING

NA PARTICIPANTS: Two groups of 15 night nurses with mild and severe daytime sleep complaints.

INTERVENTIONS

NA RESULTS: The proportion of the episode of UaMT6s excretion happening during the day (between 08:00 and 00:00 hours) was smaller in the group of nightworkers with severe daytime sleep complaints, and was negatively correlated with the severity of the complaints over the 30 subjects. A longer duration of melatonin secretion was associated with a lower severity of daytime sleep complaints. However, in most of the subjects with good daytime sleep quality, melatonin secretion remained essentially nocturnal, and the overlap with the time of their sleep episode was small or even absent.

CONCLUSIONS

Timing and duration of melatonin secretion were associated with better daytime sleep quality when the subjects had an increased proportion of melatonin secreted during the day. When there was an indication of circadian phase shift, the direction of the shift was not of primary importance for daytime sleep quality. A longer duration of melatonin secretion may increase the tolerance to an abnormal circadian phase.

Fluorescence studies of lens epithelial cells and their constituents

Steady-state and time-resolved fluorescence measurements have been made of human and rabbit lens epithelial cells and their total soluble protein. Excitation at 350 nm results in broad fluorescence spectra peaking at 450 nm and stretching into the visible past 650 nm. The fluorescence excitation spectra peak around 350 nm. We assign the species responsible for this absorption and fluorescence as NADPH. Because the absorption of near-UV light (300-400 nm) is responsible for cell damage and death, we postulate that excited states of NADPH are implicated in the mechanisms of cell damage. Preirradiation with 355 nm light leads to a loss of NADPH fluorescence but with no change in decay kinetics. Possible mechanisms for cell damage are explored.

Pathogenicity of vibrio splendidus strains associated with turbot larvae, scophthalmus maximus

Turbot larvae were challenged with eight strains of Vibrio splendidus isolated from diseased larvae, plus a ninth strain pathogenic to scallop larvae (A515; Nicolas et al. 1996). Six strains caused heavy mortality but the scallop pathogen and the other two strains did not. All the strains shared a large number of phenotypic traits, and an attempt was made to relate virulence to genotype and phenotype. Five of the six pathogenic strains were very similar, as shown by RAPD fingerprinting and phenotypic characteristics. The relatedness of the other strains was intermediate between the main pathogenic group and V. splendidus ATCC 33125, but the DNA-DNA homology between the pathogenic group and the reference strain was still high (78% of reassociation rate). The non-pathogenic isolates may be a useful tool for determining the possible virulence factors, as all the isolates differed by few characteristics.

Downregulation of cardiac AT1-receptor expression and angiotensin II concentrations after long-term blockade of the renin-angiotensin system in cardiomyopathic hamsters

We monitored cardiac angiotensin II concentration and AT1-receptor density after long-term blockade of the renin-angiotensin system in inbred control hamsters treated with placebo or losartan (100 mg/kg/day) and cardiomyopathic hamsters treated with placebo, low-(30 mg/kg/day), or high-dose (100 mg/kg/day) losartan or quinapril (100 mg/kg/day). All treatments were started at age 50 days. Angiotensin II-receptor density and affinity were measured by radioligand-binding assays, and ventricular angiotensin II concentration was determined by radioimmunoassay. After 125 and 275 days of treatment, both doses of losartan significantly reduced AT1-receptor density, whereas quinapril had no effect. The administration of both drugs resulted in significant reductions in ventricular angiotensin II concentration. The prolonged administration of losartan was associated with an increase in cardiac hypertrophy, suggesting that angiotensin II signaling is not directly involved or at least does not play a major role in the remodeling process observed in cardiomyopathic hamsters.