Towards European automatic bioaerosol monitoring: Comparison of 9 automatic pollen observational instruments with classic Hirst-type traps

To benefit allergy patients and the medical practitioners, pollen information should be available in both a reliable and timely manner; the latter is only recently possible due to automatic monitoring. To evaluate the performance of all currently available automatic instruments, an international intercomparison campaign was jointly organised by the EUMETNET AutoPollen Programme and the ADOPT COST Action in Munich, Germany (March-July 2021). The automatic systems (hardware plus identification algorithms) were compared with manual Hirst-type traps. Measurements were aggregated into 3-hourly or daily values to allow comparison across all devices. We report results for total pollen as well as for Betula, Fraxinus, Poaceae, and Quercus, for all instruments that provided these data. The results for daily averages compared better with Hirst observations than the 3-hourly values. For total pollen, there was a considerable spread among systems, with some reaching R² > 0.6 (3 h) and R² > 0.75 (daily) compared with Hirst-type traps, whilst other systems were not suitable to sample total pollen efficiently (R² < 0.3). For individual pollen types, results similar to the Hirst were frequently shown by a small group of systems. For Betula, almost all systems performed well (R² > 0.75 for 9 systems for 3-hourly data). Results for Fraxinus and Quercus were not as good for most systems, while for Poaceae (with some exceptions), the performance was weakest. For all pollen types and for most measurement systems, false positive classifications were observed outside of the main pollen season. Different algorithms applied to the same device also showed different results, highlighting the importance of this aspect of the measurement system. Overall, given the 30 % error on daily concentrations that is currently accepted for Hirst-type traps, several automatic systems are currently capable of being used operationally to provide real-time observations at high temporal resolutions. They provide distinct advantages compared to the manual Hirst-type measurements.

Meeting clinical needs for and sidestepping supply chain threats to COVID-19 testing through continuous process improvement

Introduction/Objective

The first human case of SARS-CoV-2 infection was reported in December of 2019. By late February 2020 evidence of community transmission in the United States was documented and soon it developed into a global pandemic. On March 11, 2020, the Mayo Clinic Arizona’s Microbiology Laboratory introduced a PCR test for diagnosis of SARS-CoV-2 infection. Even as testing demands exponentially increased, the hospital relied on timely results to assist in directing patient care. In order to provide timely results in the face of continuously emerging supply chain threats, we needed to increase our capacity for SARS-CoV-2 PCR testing by reducing technologist time and reagent waste, without impacting turnaround time or other quality metrics such as repeat rate.

Methods/Case Report

Technologist time was measured in hands-on time per specimen. Reagent use was defined by the volume of lysis buffer (the primary rate limiting reagent due to supply chain constraints) used per sample. Turnaround time was measured from receipt in lab until result verification and the rerun rate is the percent of specimens with an internal control (IC) failure, an indicator of specimen or process quality. Unnecessary steps were determined using a process map, spaghetti diagram and waste walk. Improvements included simplifying steps, changes to protocols and lab design. Impacts of the improvements were measured for 5 months post-implementation.

Results (if a Case Study enter NA)

Process improvements reduced technologist time per sample by 30.8 seconds and decreased critical reagent needs by 23.6%. Improvements led to $104,000 in just reagent savings over 5 months. Turnaround time and rerun rates were not negatively impacted.

Conclusion

By creating the leanest possible workflow, we were able to meet the demands for accurate and timely SARS-CoV-2 results. In future workflows, we will continue to implement lean processes and ensure the most efficient use of limited resources.

German validation of the Conners Adult ADHD Rating Scales (CAARS) II: Reliability, validity, diagnostic sensitivity and specificity

Background

The German version of the Conners Adult ADHD Rating Scales (CAARS) has proven to show very high model fit in confirmative factor analyses with the established factors inattention/memory problems, hyperactivity/restlessness, impulsivity/emotional lability, and problems with self-concept in both large healthy control and ADHD patient samples. This study now presents data on the psychometric properties of the German CAARS-self-report (CAARS-S) and observer-report (CAARS-O) questionnaires.

Methods

CAARS-S/O and questions on sociodemographic variables were filled out by 466 patients with ADHD, 847 healthy control subjects that already participated in two prior studies, and a total of 896 observer data sets were available. Cronbach's-alpha was calculated to obtain internal reliability coefficients. Pearson correlations were performed to assess test-retest reliability, and concurrent, criterion, and discriminant validity. Receiver Operating Characteristics (ROC-analyses) were used to establish sensitivity and specificity for all subscales.

Results

Coefficient alphas ranged from .74 to .95, and test-retest reliability from .85 to .92 for the CAARS-S, and from .65 to .85 for the CAARS-O. All CAARS subscales, except problems with self-concept correlated significantly with the Barrett Impulsiveness Scale (BIS), but not with the Wender Utah Rating Scale (WURS). Criterion validity was established with ADHD subtype and diagnosis based on DSM-IV criteria. Sensitivity and specificity were high for all four subscales.

Conclusion

The reported results confirm our previous study and show that the German CAARS-S/O do indeed represent a reliable and cross-culturally valid measure of current ADHD symptoms in adults.

Homozygous XYLT2 variants as a cause of spondyloocular syndrome

Spondyloocular syndrome (SOS) is a rare autosomal recessive, skeletal disorder. Two recent studies have shown that it is the result of biallelic sequence variants in the XYLT2 gene with pleiotropic effects in multiple organs, including retina, heart muscle, inner ear, cartilage, and bone. The XYLT2 gene encodes xylosyltransferase 2, which catalyzes the transfer of xylose (monosaccharide) to the core protein of proteoglycans (PGs) leading to initiating the process of PG assembly. SOS was originally characterized in 2 families A and B of Iraqi and Turkish origin, respectively. Using DNA from affected members of the same 2 families, we performed whole exome sequencing, which revealed 2 novel homozygous missense variants (c.1159C > T, p.Arg387Trp) and (c.2548G > C, p.Asp850His). Our findings extend the body of evidence that SOS is caused by homozygous variants in the XYLT2 gene. In addition, this report has extended the phenotypic description of SOS by adding follow-up data from 5 affected individuals in one of the two families, presented here.

How to Assess Prognostic Models for Survival Data: A Case Study in Oncology

Objectives: A lack of generally applicable tools for the assessment of predictions for survival data has to be recognized. Prediction error curves based on the Brier score that have been suggested as a sensible approach are illustrated by means of a case study.

Methods: The concept of predictions made in terms of conditional survival probabilities given the patient’s covariates is introduced. Such predictions are derived from various statistical models for survival data including artificial neural networks. The idea of how the prediction error of a prognostic classification scheme can be followed over time is illustrated with the data of two studies on the prognosis of node positive breast cancer patients, one of them serving as an independent test data set.

Results and Conclusions: The Brier score as a function of time is shown to be a valuable tool for assessing the predictive performance of prognostic classification schemes for survival data incorporating censored observations. Comparison with the prediction based on the pooled Kaplan Meier estimator yields a benchmark value for any classification scheme incorporating patient’s covariate measurements. The problem of an overoptimistic assessment of prediction error caused by data-driven modelling as it is, for example, done with artificial neural nets can be circumvented by an assessment in an independent test data set.

Retrospective analysis of treatment outcome in 315 patients with oligodendroglial brain tumors

Although chemotherapy with procarbazine, lomustine and vincristine (PCV) is considered to be well tolerated, side effects frequently lead to dose reduction or even discontinuation of treatment of oligodendroglial brain tumors. The primary objective of the analysis was to retrospectively compare progression-free survival (PFS) after PCV vs. PC chemotherapy (without vincristine to avoid side effects). Patients were retrospectively identified from a database containing our patients between 1990 and 2003. For the selected cases, all histopathology reports were re-evaluated by a local neuropathologist. Based on the updated histology data, patients were included in the study if they had at least one histological diagnosis of an oligodendroglial tumor. PFS after start of PCV (n = 61) and PC (n = 84) chemotherapy identical (median 30 months). Multivariate analysis adjusting for prognostic imbalances favouring the PC group showed a minor, statistically non-significant benefit for PCV (hazard ratio 0.81, 95% confidence interval 0.53–1.25; p = 0.346). Younger age (< 50 y) was a statistically significant predictor of longer PFS. Significant advantages in terms of overall survival after first diagnosis of oligodendroglial tumor (OS, n = 315) were found for patients < 50 y (p < 0.001), oligodendrogliomas versus oligoastrocytomas (p = 0.002), and WHO°II vs. °III (p < 0.001). Three risk groups regarding OS were identified. Findings support the hypothesis that PC may be as effective as PCV chemotherapy, while avoiding the additonal risks of vincristine. Younger age, lower tumor grade and histology of an oligodendroglioma were identified to be favorable prognostic factors.

Quantifying the Predictive Performance of Prognostic Models for Censored Survival Data with Time-Dependent Covariates

Prognostic models in survival analysis typically aim to describe the association between patient covariates and future outcomes. More recently, efforts have been made to include covariate information that is updated over time. However, there exists as yet no standard approach to assess the predictive accuracy of such updated predictions. In this article, proposals from the literature are discussed and a conditional loss function approach is suggested, illustrated by a publicly available data set.

A marker for Stevens-Johnson syndrome …: ethnicity matters

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare but severe cutaneous adverse drug reactions, which can be caused by a certain number of specific drugs among which is carbamazepine, an antiepileptic agent. A very strong association of carbamazepine-induced SJS with HLA-B*1502 has recently been described in the Han Chinese population. Here in, we report preliminary results from a European study (RegiSCAR) of 12 carbamazepine-induced SJS/TEN cases (nine French and three German). Among these only four had a HLA-B*1502 allele. Remarkably, these four patients had an Asian ancestry, whereas the others did not as far as we have ascertained. This shows that although the HLA region may contain important genes for SJS, the HLA-B*1502 allele is not a universal marker for this disease and that ethnicity matters.

How to assess prognostic models for survival data: a case study in oncology

OBJECTIVES

A lack of generally applicable tools for the assessment of predictions for survival data has to be recognized. Prediction error curves based on the Brier score that have been suggested as a sensible approach are illustrated by means of a case study.

METHODS

The concept of predictions made in terms of conditional survival probabilities given the patient's covariates is introduced. Such predictions are derived from various statistical models for survival data including artificial neural networks. The idea of how the prediction error of a prognostic classification scheme can be followed over time is illustrated with the data of two studies on the prognosis of node positive breast cancer patients, one of them serving as an independent test data set.

RESULTS AND CONCLUSIONS

The Brier score as a function of time is shown to be a valuable tool for assessing the predictive performance of prognostic classification schemes for survival data incorporating censored observations. Comparison with the prediction based on the pooled Kaplan Meier estimator yields a benchmark value for any classification scheme incorporating patient's covariate measurements. The problem of an overoptimistic assessment of prediction error caused by data-driven modelling as it is, for example, done with artificial neural nets can be circumvented by an assessment in an independent test data set.

High-density miniaturized thermal shift assays as a general strategy for drug discovery

More general and universally applicable drug discovery assay technologies are needed in order to keep pace with the recent advances in combinatorial chemistry and genomics-based target generation. Ligand-induced conformational stabilization of proteins is a well-understood phenomenon in which substrates, inhibitors, cofactors, and even other proteins provide enhanced stability to proteins on binding. This phenomenon is based on the energetic coupling of the ligand-binding and protein-melting reactions. In an attempt to harness these biophysical properties for drug discovery, fully automated instrumentation was designed and implemented to perform miniaturized fluorescence-based thermal shift assays in a microplate format for the high throughput screening of compound libraries. Validation of this process and instrumentation was achieved by investigating ligand binding to more than 100 protein targets. The general applicability of the thermal shift screening strategy was found to be an important advantage because it circumvents the need to design and retool new assays with each new therapeutic target. Moreover, the miniaturized thermal shift assay methodology does not require any prior knowledge of a therapeutic target's function, making it ideally suited for the quantitative high throughput drug screening and evaluation of targets derived from genomics.

Molecular basis of downregulation of G-protein-coupled inward rectifying K(+) current (I(K,ACh) in chronic human atrial fibrillation: decrease in GIRK4 mRNA correlates with reduced I(K,ACh) and muscarinic receptor-mediated shortening of action potentials

BACKGROUND

Clinical and experimental evidence suggest that the parasympathetic nervous system is involved in the pathogenesis of atrial fibrillation (AF). However, it is unclear whether changes in G-protein-coupled inward rectifying K(+) current (I(K,ACh)) contribute to chronic AF.

METHODS AND RESULTS

In the present study, we used electrophysiological recordings and competitive reverse-transcription polymerase chain reaction to study changes in I(K,ACh) and the level of the I(K,ACh) GIRK4 subunit in isolated human atrial myocytes and the atrial tissue of 39 patients with sinus rhythm and 24 patients with chronic AF. The density of I(K,ACh) was approximately 50% smaller in myocytes from patients with AF compared with those in sinus rhythm, and this was accompanied by decreased levels of GIRK4 mRNA. The current density of the inward rectifying K(+) current (I(K1)) was 2-fold larger during AF than in sinus rhythm, in correspondence with an increase in Kir2.1 mRNA. The larger I(K1) in AF is consistent with more negative membrane potentials in right atrial trabeculae from AF patients. Moreover, action potential duration was reduced in AF, and the action potential shortening produced by muscarinic receptor stimulation was attenuated, indicating that the changes of I(K1) and I(K,ACh) were functionally relevant.

CONCLUSIONS

Chronic human AF induces transcriptionally mediated upregulation of I(K1) but downregulation of I(K,ACh) and attenuates the muscarinic receptor-mediated shortening of atrial action potentials. This suggests that atrial myocytes adapt to a chronically high rate by downregulating I(K,ACh) to counteract the shortening of the atrial effective refractory period due to electrical remodeling.

[Preoperative chemotherapy in primary operable breast cancer with a dose-dense combination of doxorubicin and docetaxel (ADoc) - Experience of the GEPARDO-GABG study group]

OBJECTIVE

The German Adjuvant Breast Cancer Study Group (GABG) conducts trials of preoperative chemotherapy in patients with primary breast cancer using a combination of doxorubicin and docetaxel (ADoc). -

PATIENTS AND METHODS

We conducted a parallel-grouped phase IIa-study with 42 patients with a conventionally dosed and a dose-dense ADoc-schedule (4 cycles of Doxorubicin 50 mg/m(2), Docetaxel 75 mg/m(2) i. v. day 1, q day 15 or 22; G-CSF day 3-15 only for the dose-dense schedule) and a randomized phase IIb-study (GEPARDO-Study) with 250 patients with ADoc +/- Tamoxifen. Biological factors were determined immunohistochemically on 197 core biopsies before treatment. A comparison to a sequential AC-Doc regimen including 913 patients has been completed recently. -

RESULTS

ADoc can be applicated on schedule in 93 % of all patients. The dose-dense regimen shows a tendency to more toxicity but also to more efficacy. The rate of complete pathological remissions (pCR) was 9.7 %. No difference was found between chemo- and chemoendocrine treatment. Clinically negative lymphnodes and a negative estrogen receptor status is predictive for a higher pCR-rate. To date no differences in toxicity could be found between ADoc and AC-Doc. -

CONCLUSIONS

The dose-dense ADoc regimen is well tolerated and highly effective as preoperative therapy of breast cancer.

Dose-dense doxorubicin, docetaxel, and granulocyte colony-stimulating factor support with or without tamoxifen as preoperative therapy in patients with operable carcinoma of the breast: a randomized, controlled, open phase IIb study

PURPOSE

To investigate the effect of adding tamoxifen to a preoperative dose-dense doxorubicin and docetaxel regimen on the pathologic response of primary operable breast cancer.

PATIENTS AND METHODS

Patients (tumor size > or = 3 cm, N0 to 2, M0) were prospectively randomized to receive every 14 days a total of four cycles of doxorubicin 50 mg/m2 and docetaxel 75 mg/m(2), either with (ADocT) or without (ADoc) simultaneous tamoxifen. Granulocyte colony-stimulating factor (G-CSF) was routinely given on days 5 to 10. Surgery followed 8 to 10 weeks after the start of treatment.

RESULTS

Within 14 months, 250 patients were included in the study at 56 centers. Of 992 planned cycles, 97.9% were administered. Pathologically complete remission (pCR) with no detectable viable tumor cells was achieved in 9.7%. There was a nonsignificant difference of -1.2% in favor of ADoc, with a 95% confidence interval of -8.6% to 6.2%. A further 2.4% had only noninvasive tumor residues, and 13.8% had focal invasive residues. Complete and partial responses detected by palpation were observed in 28.9% and 52.4%, respectively. The response rates (complete and partial) by best appropriate imaging methods were 77.5% and 67.5% for ADocT and ADoc, respectively. Breast conservation was possible in 68.8% of the patients. A tendency toward more frequent toxic events was observed with ADocT treatment. Significant predictors of pCR to chemotherapy were negative lymph node and negative estrogen receptor status.

CONCLUSION

A dose-dense regimen of ADoc with G-CSF offers high compliance, moderate toxicity, and rapid efficacy as a form of preoperative chemotherapy in operable breast cancer. Concurrent treatment with tamoxifen for 8 weeks could not improve the pathologic response rate.

Evidence for Edg-3 receptor-mediated activation of I(K.ACh) by sphingosine-1-phosphate in human atrial cardiomyocytes

Sphingosine-1-phosphate (SPP) and sphingosylphosphorylcholine (SPPC) have been reported to activate muscarinic receptor-activated inward rectifier K(+) current (I(K.ACh)) in cultured guinea pig atrial myocytes with similar nanomolar potency. Members of the endothelial differentiation gene (Edg) receptor family were recently identified as receptors for SPP; however, these receptors respond only to micromolar concentrations of SPPC. Here we investigated the sphingolipid-induced activation of I(K.ACh) in freshly isolated guinea pig, mouse, and human atrial myocytes. SPP activated I(K.ACh) in atrial myocytes from all three species with a similar nanomolar potency (EC(50) values: 4-8 nM). At these low concentrations, SPPC also activated I(K.ACh) in guinea pig myocytes. In contrast, SPPC was almost ineffective in mouse and human myocytes, thus resembling the pharmacology of the Edg receptors. Transcripts of Edg-1, Edg-3, and Edg-5 were detected in human atrial cells. Moreover, activation of I(K.ACh) by SPP was blocked by the Edg-3-selective antagonist suramin, which did not affect basal or carbachol-stimulated K(+) currents. In conclusion, these data indicate that I(K.ACh) activation by SPP and SPPC exhibits large species differences. Furthermore, they suggest that SPP-induced I(K.ACh) activation in human atrial myocytes is mediated by the Edg-3 subtype of SPP receptors.

Multiple organ dysfunction after remote circulatory arrest: common pathway of radical oxygen species?

OBJECTIVES

Cardiovascular, respiratory, and vascular dysfunction can follow trauma-induced no-flow-reflow states: hemorrhage, blunt trauma, or neurogenic shock. Liver ischemia-reperfusion (IR) induces remote lung damage by means of xanthine oxidase (XO) pro-oxidant activity. This damage was not proven in the heart, neither was the independent role of radical oxygen species (ROS) established in such cases. We investigated whether multiple organ dysfunction after a trauma-like IR is XO and ROS related and whether clinically used ROS scavengers could be beneficial.

METHODS

A controlled, randomized trial in which isolated rat livers, hearts, lungs, and aortic rings were perfused with Krebs-Henseleit solutions. After stabilization, livers were either perfused or made ischemic (2 hours). Then, pairs of liver plus heart, lung, or ring were reperfused in series (15 minutes), and then the second organ circulated alone for 45 minutes. Remote organ protection against the pro-oxidant hepatic-induced toxicity was evaluated by using allopurinol (1 mmol/L, heart), mannitol (0.25 g/kg, lung), or methylene blue (40 mg/kg, ring).

RESULTS

IR liver effluents typically contained high lactate dehydrogenase, XO, and uric acid concentrations compared with control organs. IR was associated with doubled lung peak inspiratory pressure and reduced static compliance. Myocardial velocity of contraction and relaxation decreased by one third of baseline, and rings contracted abnormally and responded inadequately to phenylephrine. Wet-weight to dry-weight ratios in the remote organs increased as well. Most remote reperfusion injuries were attenuated by the drugs.

CONCLUSION

Liver no-flow-reflow directly induces myocardial, pulmonary, and vascular dysfunction. These are likely mediated by XO and ROS. The tested drugs protected against these pro-oxidants, even in the presence of circulating XO.

Assessment and comparison of prognostic classification schemes for survival data

Prognostic classification schemes have often been used in medical applications, but rarely subjected to a rigorous examination of their adequacy. For survival data, the statistical methodology to assess such schemes consists mainly of a range of ad hoc approaches, and there is an alarming lack of commonly accepted standards in this field. We review these methods and develop measures of inaccuracy which may be calculated in a validation study in order to assess the usefulness of estimated patient-specific survival probabilities associated with a prognostic classification scheme. These measures are meaningful even when the estimated probabilities are misspecified, and asymptotically they are not affected by random censorship. In addition, they can be used to derive R(2)-type measures of explained residual variation. A breast cancer study will serve for illustration throughout the paper.

Circulatory levels of catecholamines, serotonin and lipids in attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) may be associated with a dysregulation of the catecholaminergic and serotonergic systems. Furthermore, ADHD is frequently complicated by aggressive impulsive behaviour, which is suggested to be related to low serum cholesterol levels. We examined the relationship between blood serotonin, norepinephrine, dopa and lipid levels and the degree of hyperactivity, impulsiveness, lack of concentration, and aggressiveness in boys with ADHD of low and high severity as determined by a specially designed formulated scale based on the DSM-IV criteria for ADHD. No differences were noted between the groups in any of the peripheral biological parameters except blood serotonin, for which a tendency (P=0.08) towards lower levels was observed in the children with more severe disorder. We conclude that children with severe ADHD may have a different serotonin turnover compared to children with mild ADHD. These results may have implications for our understanding of the pathogenesis of ADHD, at least the more severe type.

Results after surgery in stage-I bronchogenic carcinoma

BACKGROUND

The aim of this retrospective study was to evaluate prognostic factors for recurrence-free survival in stage-I non-small-cell bronchogenic carcinoma.

METHODS

During 9 years, 338 consecutive patients were operated on for stage-I bronchogenic carcinoma. Patients with small-cell carcinoma (n = 14), prior malignancies in locations other than pulmonary (n = 41), and patients with incomplete data on prognostic factors (n = 11) were excluded. Of the remaining 272 patients 226 were men. Mean age was 63 years (40 to 81 years). The resections performed comprised 215 lobectomies and bilobectomies, 36 segmentectomies and wedge resections, and 21 pneumonectomies. According to the number of sites of dissected lymph nodes 3 subgroups were formed: group A with 0 to 4 (n = 71), B with 5 to 6 (n = 118), and C with 7 to 10 sites (n = 83). Median follow-up was 46 months.

RESULTS

Three patients (1.1 %) died within 30 days of operation. In 3 patients the resection was revealed to be not radical (R1). At the end of follow-up, 191 patients were alive, 174 of these without recurrence. Eighty-one patients had died, 53 associated with tumor recurrence. Four patients had died of non-pulmonary malignancies. Twenty-two patients died of causes not related to tumor disease. In 2 patients the cause of death could not be determined retrospectively. Overall 5-year survival was 65% (95% confidence interval [CI] 58-72%), recurrence-free survival 59% (CI 51-66%). Significant prognostic factors for recurrence-free survival were T stage (relative risk [RR] 1.7 for T2 vs. T1, CI 1.0-3.0), age (RR 1.9 for >70 years vs. < or =70 years, CI 1.1-3.1), adeno cell type (RR 2.3 vs. squamous cell, CI 1.4-4.0), as well as lymphangiosis carcinomatosa (RR 2.3, CI 1.2-4.4). Extent of operative resection, extent of lymphadenectomy, and sex did not influence survival.

CONCLUSION

5-year survival of our patients was in the range reported in literature. Most patients died of distant metastases. Our retrospective study probably underestimated the occurrence of second primary cancers of the lung. Limited resection in poor-risk patients showed equivalent results to lobectomy. The extent of lymph-node resections had no influence on survival of stage-I patients, however, it must be remembered that positive results in lymph nodes shift patients to higher stages.

Evaluation of Vitacel M80K as a new direct compressible vehicle

Vitacel M80K, a cellulose powder coated with 2% colloidal silica, is a recently developed direct compressible vehicle (DCV). The aim of this study is to investigate the performance of M80K, in comparison with: a laboratory prepared vehicle (ELC+) consisting of a mixture of Elcema P050 (ELC) and 2% Aerosil, and a microcrystalline cellulose (MCC), Avicel PH 101 (Avicel). Bulk density, flow and surface characteristics of the DCVs were determined. Tablets were prepared by direct compression using various drugs; ascorbic acid (fine and coarse crystals), cimetidine, and paracetamol. Tablets prepared with M80K showed less weight variation than those prepared with Avicel. Ascorbic acid-Avicel tablets were slightly harder than those with M80K. However, in the presence of either cimetidine or paracetamol, M80K resulted in the production of tablets with maximum hardness. In most cases, except with paracetamol, M80K produced tablets with slightly higher friability in comparison to Avicel, while ELC+ showed maximum friability. M80K-paracetamol tablets showed the minimum friability values and highest hardness sensitivity towards increase of the applied compression force between 5 and 35 kN. M80K-containing formulations showed better hardness tolerance upon the addition of magnesium stearate. Disintegration times for most tablets were relatively short (<5 min).

Octreotide ameliorates glucose intolerance following acute experimental pancreatitis

The long-term effects of octreotide, the synthetic analog of the hormone somatostatin, on acute experimental pancreatitis were studied. Acute pancreatitis was induced in rats by intraparenchymal injections of 0.5 ml 5% or 10% sodium taurocholate. Octreotide (10 mg/kg/day, subcutaneously), or saline injections as controls, were started four hours later, and their effects were assessed 30, 60, and 90 days after the induction of pancreatitis. Neither intrapancreatic saline injections nor octreotide administration without the induction of pancreatitis caused any biochemical or histological abnormalities. Taurocholate-induced pancreatitis was followed by remarkable hyperglycemia, which was ameliorated by octreotide. Thirty days after induction of pancreatitis, glucose levels were 269+/-21 mg/100 ml and 153+/-17 mg/100 ml in the control and octreotide treated animals, respectively (P < 0.02). Octreotide administration was associated with increased pH values after 60 and 90 days (P < 0.05 for the 90 days group). The levels of hematocrit, calcium, and amylase were already within the normal ranges after 30 days and were unaffected by octreotide. There were no signs of chronic exocrine insufficiency and all the surviving rats gained weight during the follow-up. However, the relative weights of the pancreases of the octreotide-treated animals were higher than those of the controls 30 days after IOP. Histopathological evaluation demonstrated regeneration of the pancreatic tissue, and increased number and hypertrophy of the islets of Langherhans. There were no significant differences whether the octreotide treatment was given for only 48 or 96 hr. Survival was significantly improved by octreotide; only one octreotide-treated rat (2.5%) with 10% taurocholate-induced pancreatitis died, while six (15%) of the control animals succumbed (P < 0.05). These studies provided data on the sequelae of acute pancreatitis and showed that octreotide may have long-term beneficial effects in this disease.

[Macroenzymes: an interesting laboratory finding, without clinical relevance]

Macroenzymes are complexes of serum enzymes with proteins which have a higher molecular weight and longer plasma half-life than the normal enzyme. The presence of macroenzymes is suggested by finding increased serum enzyme activity, not associated with symptoms. Thus, macroenzymes can cause diagnostic errors and the performance of unnecessary tests or invasive procedures. We describe 2 patients with highly elevated serum levels of lactate dehydrogenase (LDH) and creatine kinase (CK) due to formation of complexes with immunoglobulin G. 1 patient had LDH of 4500 u/L but was otherwise normal and in the second CK was elevated with no evidence of ischemic heart disease. Awareness of the phenomenon of macroenzymes may save the patient long and sometimes invasive investigation.

Direct induction of acute lung and myocardial dysfunction by liver ischemia and reperfusion

OBJECTIVES

To investigate whether liver ischemia and reperfusion (IR) directly affect functions of remote organs.

BACKGROUND

Cardiovascular and respiratory dysfunction follows hemorrhage, spinal shock, or trauma as a result of no-flow-reflow phenomena. Hepatic IR induces remote organ damage probably by xanthine oxidase and oxygen species.

MATERIALS AND METHODS

Isolated rat livers, lungs, and hearts were perfused with Krebs-Henseleit solutions. After stabilization, livers were either perfused or made ischemic. Then, livers and hearts or livers and lungs were reperfused in series, and the liver was disconnected and the second organ continued to perfuse with the accumulated effluents.

MEASUREMENTS AND MAIN RESULTS

Ischemic and reperfused liver effluent contained high lactate dehydrogenase and uric acid concentrations compared with controls; xanthine oxidase increased 60 to 100 times. Ischemic and reperfused lung peak inspiratory pressure almost doubled; airway static compliance halved; myocardial contractility decreased to 70% of baseline; wet weight-to-dry weight ratios of lungs and livers increased.

CONCLUSION

Ischemic and reperfused liver can directly induce myocardial and pulmonary dysfunction, presumably by oxidant-induced injury.

Antioxidant functions of inositol 1,2,3-trisphosphate and inositol 1,2,3,6-tetrakisphosphate

Iron chelates of inositol 1,2,3-trisphosphate and inositol 1,2,3,6-tetrakisphosphate lacked free coordination sites and prevented the iron-catalyzed oxidation of ascorbic acid and peroxidation of arachidonic acid. In contrast, iron chelates of inositol 1,2,6-trisphosphate and inositol 1,2,5,6-tetrakisphosphate contained available coordination sites, permitted iron-catalyzed ascorbic acid oxidation, and enhanced arachidonic acid peroxidation. It was concluded that the 1,2,3-trisphosphate grouping of inositol hexakisphosphate was responsible for the inhibition of iron-catalyzed hydroxyl radical formation. The structure of the chelate with the phosphates in an axial-equatorial-axial configuration appeared to be the only possible inositol trisphosphate that could form bonds between six oxygen atoms and the six coordination sites on iron. Km values for cleavage by Escherichia coli alkaline phosphatase were as follows: inositol 1,2,3-trisphosphate, 56 microM; inositol 1,2,6-trisphosphate, 35 microM; inositol 1,2,3,6-tetrakisphosphate, 139 microM; and inositol 1,2,5,6-tetrakisphosphate, 100 microM. The initial hydrolysis rates of 200 microM solutions of the latter three isomers by E. coli alkaline phosphatase were not affected by an equimolar concentration of iron, whereas the rate for inositol 1,2,3-trisphosphate decreased in the presence of iron to 50% of the control. Therefore, the antioxidant potential of inositol 1,2,3-trisphosphate and inositol 1,2,3,6-tetrakisphosphate in cells and other biological systems may be fortified by the resistance of their iron chelates to enzymatic hydrolysis of the functional 1,2,3-trisphosphate array.

Effects of delayed administration of octreotide in acute experimental pancreatitis

Multiple therapeutic modalities studied for acute pancreatitis often show a poor correlation between results obtained in experimental studies and results of clinical trials. One of the main reasons for this discrepancy is that in most experimental studies the drugs were administered immediately after induction of pancreatitis, whereas in the clinical setting there is almost always a delay between the onset of the disease and initiation of the treatment. We studied the effects of a delayed treatment with octreotide, the synthetic analogue of the hormone somatostatin, on acute experimental pancreatitis in rats. The disease was induced by intraparenchymal injections of 0.5 ml 5% sodium taurocholate, and octreotide (10 mg/kg/day s.c.) was started either 4 or 12 hr later. Subcutaneous saline injections were used in controls. One-half of the animals of each study group was sacrificed after 36 hr, and the following parameters were examined: pancreatic weight, plasma pH, serum calcium and amylase, and histopathological damage. The same parameters, as well as survival, were assessed after 20 days in the remaining rats. Neither intrapancreatic saline injections, nor octreotide administration without the induction of pancreatitis, caused any biochemical or histological alterations. Hypocalcemia and acidosis in pancreatitis-induced rats were improved by octreotide, but, as expected, it had no effect on amylase levels. Octreotide ameliorated pancreatic edema, intestinal dilatation, and the histopathological injury score 36 hr after induction of pancreatitis. Mortality was 40% in control animals, and only 20% in rats treated with octreotide. Overall, octreotide had beneficial effects in acute experimental pancreatitis, and was more effective when started earlier. These results indicate that octreotide may have a role in the management of acute pancreatitis.