Genetic diversity within leukemia-associated immunophenotype-defined subclones in AML.

Acute myeloid leukemia (AML) is a highly heterogeneous disease showing dynamic clonal evolution patterns over time. Various subclones may be present simultaneously and subclones may show a different expansion pattern and respond differently to applied therapies. It is already clear that immunophenotyping and genetic analyses may yield overlapping, but also complementary information. Detailed information on the genetic make-up of immunophenotypically defined subclones is however scarce. We performed error-corrected sequencing for 27 myeloid leukemia driver genes in 86, FACS-sorted immunophenotypically characterized normal and aberrant subfractions in 10 AML patients. We identified three main scenarios. In the first group of patients, the two techniques were equally well characterizing the malignancy. In the second group, most of the isolated populations did not express aberrant immunophenotypes but still harbored several genetic aberrancies, indicating that the information obtained only by immunophenotyping would be incomplete. Vice versa, one patient was identified in which genetic mutations were found only in a small fraction of the immunophenotypically defined malignant populations, indicating that the genetic analysis gave an incomplete picture of the disease. We conclude that currently, characterization of leukemic cells in AML by molecular and immunophenotypic techniques is complementary, and infer that both techniques should be used in parallel in order to obtain the most complete view on the disease.

Silicone adhesive multilayer foam dressings as adjuvant prophylactic therapy to prevent hospital-acquired pressure ulcers: a pragmatic noncommercial multicentre randomized open-label parallel-group medical device trial.

BACKGROUND: Silicone adhesive multilayer foam dressings are used as adjuvant therapy to prevent hospital-acquired pressure ulcers (PUs). OBJECTIVES: To determine whether silicone foam dressings in addition to standard prevention reduce the incidence of PUs of category 2 or worse compared with standard prevention alone. METHODS: This was a multicentre, randomized controlled medical device trial conducted in eight Belgian hospitals. At-risk adult patients were centrally randomized (n = 1633) to study groups based on a 1 : 1 : 1 allocation: experimental groups 1 (n = 542) and 2 (n = 545) - pooled as the treatment group - and the control group (n = 546). The experimental groups received PU prevention according to hospital protocol, and a silicone foam dressing on the relevant body sites. The control group received standard of care. The primary endpoint was the incidence of a new PU of category 2 or worse at the studied body sites. RESULTS: In the intention-to-treat population (n = 1605), PUs of category 2 or worse occurred in 4·0% of patients in the treatment group and 6·3% in the control group [relative risk (RR) 0·64, 95% confidence interval (CI) 0·41-0·99, P = 0·04]. Sacral PUs were observed in 2·8% and 4·8% of the patients in the treatment group and the control group, respectively (RR 0·59, 95% CI 0·35-0·98, P = 0·04). Heel PUs occurred in 1·4% and 1·9% of patients in the treatment and control groups, respectively (RR 0·76, 95% CI 0·34-1·68, P = 0·49). CONCLUSIONS: Silicone foam dressings reduce the incidence of PUs of category 2 or worse in hospitalized at-risk patients when used in addition to standard of care. The results show a decrease for the sacrum, but no statistical difference for the heel and trochanter areas.

Determinants of lenalidomide response with or without erythropoiesis-stimulating agents in myelodysplastic syndromes: the HOVON89 trial.

A randomized phase-II study was performed in low/int-1 risk MDS (IPSS) to study efficacy and safety of lenalidomide without (arm A) or with (arm B) ESA/G-CSF. In arm B, patients without erythroid response (HI-E) after 4 cycles received ESA; G-CSF was added if no HI-E was obtained by cycle 9. HI-E served as primary endpoint. Flow cytometry and next-generation sequencing were performed to identify predictors of response. The final evaluation comprised 184 patients; 84% non-del(5q), 16% isolated del(5q); median follow-up: 70.7 months. In arm A and B, 39 and 41% of patients achieved HI-E; median time-to-HI-E: 3.2 months for both arms, median duration of-HI-E: 9.8 months. HI-E was significantly lower in non-del(5q) vs. del(5q): 32% vs. 80%. The same accounted for transfusion independency-at-week 24 (16% vs. 67%), but similar in both arms. Apart from presence of del(5q), high percentages of bone marrow lymphocytes and progenitor B-cells, a low number of mutations, absence of ring sideroblasts, and SF3B1 mutations predicted HI-E. In conclusion, lenalidomide induced HI-E in patients with non-del(5q) and del(5q) MDS without additional effect of ESA/G-CSF. The identified predictors of response may guide application of lenalidomide in lower-risk MDS in the era of precision medicine. (EudraCT 2008-002195-10).

[The role of the general practitioner in the treatment of suicidal patients: the problems they encounter in practice]. / De rol van huisartsen bij suïcidale patiënten.

In this commentary, the current directives and supporting methods to assess suicidal behaviour are briefly introduced and their shortcoming in predicting the risk of suicide is acknowledged. The treatment of a patient with suicidal behaviour by a general practitioner (GP), based on an already existing relationship between the two, is questioned. Instead, a close collaboration between GP and emergency mental healthcare providers is recommended. This working relationship should be maintained by both parties. Suicide after an intervention can have a major impact on the professionals involved. Therefore, these cases deserve specialised attention to ensure sustainable commitment of healthcare professionals confronted with complex mental health cases.

[Clonal hematopoiesis: a risk factor for leukemia and cardiovascular disease?] / Klonale hematopoëse.

Upon ageing, hematopoietic stem or progenitor cells harboring acquired leukemia-associated mutations may expand clonally and become detectable in peripheral blood. So-called clonal hematopoiesis may be detected in 5-55% of (otherwise healthy) individuals aged ≥ 70 years. Clonal hematopoiesis is associated with a higher risk of developing hematological neoplasms, although most individuals never develop malignant disease. Surprisingly, clonal hematopoiesis is also recognized as a new cardiovascular risk factor. Specific patient categories may be at higher risk for the consequences of clonal hematopoiesis. For future risk stratification, there is a need to distinguish high-risk clonal hematopoiesis from 'physiological' ageing processes. In this article we summarize current knowledge on clonal hematopoiesis and its clinical implications. Given the widespread application of next-generation sequencing in routine diagnostics, multidisciplinary recommendations for clinical management of individuals with detected clonal hematopoiesis should be developed.

Constitutive expression in gal7 mutants of Kluyveromyces lactis is due to internal production of galactose as an inducer of the Gal/Lac regulon.

The induction process of the galactose regulon has been intensively studied, but until now the nature of the inducer has remained unknown. We have analyzed a delta gal7 mutant of the yeast Kluyveromyces lactis, which lacks the galactotransferase activity and is able to express the genes of the Gal/Lac regulon also in the absence of galactose. We found that this expression is semiconstitutive and undergoes a strong induction during the stationary phase. The gal1-209 mutant, which has a reduced kinase activity but retains its positive regulatory function, also shows a constitutive expression of beta-galactosidase, suggesting that galactose is the inducer. A gal10 deletion in delta gal7 or gal1-209 mutants reduces the expression to under wild-type levels. The presence of the inducer could be demonstrated in both delta gal7 crude extracts and culture medium by means of a bioassay using the induction in gal1-209 cells. A mutation in the transporter gene LAC12 decreases the level of induction in gal7 cells, indicating that galactose is partly released into the medium and then retransported into the cells. Nuclear magnetic resonance analysis of crude extracts from delta gal7 cells revealed the presence of 50 microM galactose. We conclude that galactose is the inducer of the Gal/Lac regulon and is produced via UDP-galactose through a yet-unknown pathway.

Application of liquid chromatography-mass spectrometry to measure the concentrations and study the synthesis of short chain fatty acids following stable isotope infusions.

A new method involving zinc sulphate deproteinization was developed to study short chain fatty acids (SCFA) production in the colon and subsequent occurrence of SCFA in blood. SCFA were baseline separated in a 30 min cycle using ion-exclusion chromatography and detected by mass spectrometry. Concentrations could be measured down to 10 microM and isotopomeric distributions could be assessed, enabling the conduction of tracer studies to study changes in SCFA synthesis. The applicability of the method was tested in an extensively characterized pig model yielding portal SCFA concentrations ranging from 70 microM (butyric acid) to 150 microM (propionic acid) to 440 microM (acetic acid) prior to butyrate tracer infusion, reaching butyric acid isotopic steady state within 2 h.

The anaerobic oxidation of ammonium.

From recent research it has become clear that at least two different possibilities for anaerobic ammonium oxidation exist in nature. 'Aerobic' ammonium oxidizers like Nitrosomonas eutropha were observed to reduce nitrite or nitrogen dioxide with hydroxylamine or ammonium as electron donor under anoxic conditions. The maximum rate for anaerobic ammonium oxidation was about 2 nmol NH4+ min-1 (mg protein)-1 using nitrogen dioxide as electron acceptor. This reaction, which may involve NO as an intermediate, is thought to generate energy sufficient for survival under anoxic conditions, but not for growth. A novel obligately anaerobic ammonium oxidation (Anammox) process was recently discovered in a denitrifying pilot plant reactor. From this system, a highly enriched microbial community with one dominating peculiar autotrophic organism was obtained. With nitrite as electron acceptor a maximum specific oxidation rate of 55 nmol NH4+ min-1 (mg protein)-1 was determined. Although this reaction is 25-fold faster than in Nitrosomonas, it allowed growth at a rate of only 0.003 h-1 (doubling time 11 days). 15N labeling studies showed that hydroxylamine and hydrazine were important intermediates in this new process. A novel type of hydroxylamine oxidoreductase containing an unusual P468 cytochrome has been purified from the Anammox culture. Microsensor studies have shown that at the oxic/anoxic interface of many ecosystems nitrite and ammonia occur in the absence of oxygen. In addition, the number of reports on unaccounted high nitrogen losses in wastewater treatment is gradually increasing, indicating that anaerobic ammonium oxidation may be more widespread than previously assumed. The recently developed nitrification systems in which oxidation of nitrite to nitrate is prevented form an ideal partner for the Anammox process. The combination of these partial nitrification and Anammox processes remains a challenge for future application in the removal of ammonium from wastewater with high ammonium concentrations.

Radioimmunochemical determination of carbamoyl-phosphate synthase (ammonia) content of adult rat liver.

1. Rabbit antiserum was raised against purified carbamoyl-phosphate synthase (ammonia) from rat liver. 2. The antiserum proved to be specific in double-diffusion test and reacted in an in situ immunohistochemical test on rat liver proteins fractionated on a sodium dodecyl sulphate polyacrylamide gel only in the region where carbamoyl-phosphate synthase (ammonia) migrated. 3. This antiserum was used for setting up a radioimmunochemical determination of carbamoyl-phosphate synthase (ammonia) in cetyltrimethylammonium bromide extracts of rat liver. To obtain reproducible results in this assay it was necessary to treat the unlabelled ligand with sodium dodecyl sulphate and dithiothreitol. This treatment led to a large increase in the percentage of labelled ligand displaceable by added unlabelled ligand. 4. Radioimmunochemical determination showed that adult rat liver (3-month old) contains 5.5 mg carbamoyl-phosphate synthase (ammonia) protein per gram wet weight.

Inhibitor of apoptosis proteins: new therapeutic targets in hematological cancer?

Apoptosis is an essential process for the selection and survival of lymphocytes. Resistance to apoptosis can promote malignant transformation of hematopoietic cells. Proteins that regulate apoptosis may therefore be critically involved in the development of hematological cancer. A delicate balance between pro- and antiapoptotic mechanisms determines whether a cell death signal can activate the execution of the apoptotic cell death program. The family of inhibitor of apoptosis (IAP) proteins is a recently identified, novel category of apoptosis-regulatory proteins. IAPs can inhibit the activation of caspases that are the executioners of apoptosis, activated by both the extrinsic and intrinsic pathway. IAPs may thereby set the threshold for apoptosis-activation and play a key role in the regulation of apoptotic cell death. IAPs themselves are also subject to strict regulation through feedback mechanisms. This paper focuses on the role of IAP family proteins in the regulation of apoptosis and discusses implications for their involvement in cancer and possible use for cancer therapy, especially in leukemias and lymphomas.

Three-dimensional distribution of DNase I-sensitive chromatin regions in interphase nuclei of embryonal carcinoma cells.

In situ nick-translation allows the visualization of nuclease-sensitive chromatin regions in interphase nuclei. We have analyzed the three-dimensional (3-D) distribution of DNase I-sensitive regions of chromatin in nuclei from mouse P19 embryonal carcinoma cells by making optical sections using confocal scanning laser microscopy. In undifferentiated as well as embryonal carcinoma cells differentiated in vitro, DNase I-sensitive regions of chromatin are observed as discrete spots in the nucleus. These spots represent clusters of DNase I-sensitive sites. By optical sectioning, we show that these spots are preferentially, but not exclusively, localized at the nuclear periphery. No differences were observed in the spatial distribution of DNase I-sensitive sites in P19 EC cells or the differentiated P19 END-2 cells. Furthermore, we did not observe differences in the distribution of DNase I-sensitive chromatin regions during the cell cycle. These findings indicate, at least for P19 mouse embryonal carcinoma cells and their differentiated derivative END-2, that the compartmentalization of DNase I-sensitive chromatin regions is a general characteristic of the nucleus, independent of cell cycle stage or differentiation state. Since evidence has been presented that DNase I-sensitive sites are associated with actively transcribed chromatin, our results indicate that active transcribing chromatin is compartmentalized, preferentially in the periphery of the nucleus.

Control of the changes in rat-liver carbamoyl-phosphate synthase (ammonia) protein levels during ontogenesis: evidence for a perinatal change in immunoreactivity of the enzyme.

To analyze the changes in rat-liver carbamoyl-phosphate synthase (Cpase) protein levels during ontogenesis, these levels were determined by means of two independent methods, i.e. radioimmunoassay and densitometric assay. During normal development the changes in catalytic activity of Cpase are accompanied by equivalent changes in the quantities of enzyme protein. We have obtained evidence for the existence of a perinatal Cpase which is immunochemically different from adult Cpase as immunoreactivity of Cpase decreases in the perinatal period and remains constant thereafter.

Ultrastructural localization of nuclear matrix proteins in HeLa cells using silver-enhanced ultra-small gold probes.

We describe a method for immunogold staining of nuclear matrix proteins using ultra-small gold particles. The nuclear matrix of HeLa cells is obtained by two fractionation steps: (a) cell permeabilization with Triton X-100 to isolate the cytoskeleton, and (b) nuclease digestion followed by an incubation in 0.25 M ammonium sulfate to isolate the nuclear matrix. To prevent redistribution of internal matrix proteins during nuclear matrix preparation, pre-fixation with 0.1% acrolein was performed. Under this condition up to 80% of protein and 90% of DNA and RNA could be removed on nuclear matrix isolation, without redistribution of internal nuclear matrix proteins. For immunogold labeling, 1-nm gold probes appeared to be required to obtain optimal penetration into the nucleus. These particles can be visualized after silver enhancement. After gold labeling the matrices are stained, embedded in Epon, and ultra-thin sections are prepared for examination in the electron microscope. The applicability of this method is examplified by the localization of a 125 KD internal nuclear matrix protein and the lamins A and C in nuclear matrix preparations of HeLa cells.

Immunohistochemical localization of carbamoyl-phosphate synthetase (ammonia) in adult rat liver; evidence for a heterogeneous distribution.

Different fixation media have been compared in order to find one that preserves the histological structure of rat liver and allows unambiguous immunohistochemical detection of carbamoyl-phosphate synthetase (ammonia). Fixation of rat liver in a mixture of methanol, acetone, and water yields the most intense immunohistochemical staining. Using a specific antiserum raised against rat liver carbamoyl-phosphate synthetase, less than 1% of the enzyme protein is extractable after this fixation procedure, and the histological structure is similar to that after fixation in Bouin's fixative. Specific immunohistochemical staining is localized exclusively in the cytoplasm of the parenchymal cells; its granular distribution is in accordance with the mitochondrial localization of carbamoyl-phosphate synthetase. Immunohistochemical staining shows a heterogeneous distribution within the liver acinus. Staining is most intense around the portal venules, decreases slowly toward the hepatic venules and is, after an abrupt decrease, virtually absent in a limited area surrounding these venules. The possible significance of the heterogeneous distribution of carbamoyl-phosphate synthetase for ammonia metabolism is discussed.

Glaucoma phenotype in pedigrees with the myocilin Thr377Met mutation.

OBJECTIVE: To investigate the phenotype and age-related penetrance of primary open-angle glaucoma (POAG) in Australian families with the myocilin mutation Thr377Met. METHOD AND DESIGN: Cross-sectional genetic study. Four unrelated pedigrees carrying the Thr377Met mutation were ascertained from more than 2000 consecutive cases of POAG in the Glaucoma Inheritance Study in Tasmania and from families with glaucoma referred to the study from throughout Australia. Index cases and available family members were examined for signs of glaucoma, and the presence of the GLC1A Thr377Met mutation was ascertained by single-strand conformation polymorphism analysis and subsequent direct sequencing. RESULTS: From the 4 pedigrees carrying the Thr377Met mutation, 23 individuals with either ocular hypertension (OHT) or POAG were found, with a mean +/- SD age at diagnosis of 41.2 +/- 11.5 years, and a mean peak intraocular pressure of 31.7 +/- 9.9 mm Hg. A further 9 mutation carriers older than 18 years were studied who as yet showed no signs of OHT or POAG (6 of these 9 were younger than 30 years). A single individual with POAG was identified who did not carry the Thr377Met mutation. For Thr377Met carriers, age-related penetrance for OHT or POAG was 88% at age 30 years. A positive family history of POAG was present for 3 of the 4 index cases. Thirteen (57%) of the 23 Thr377Met carriers with OHT or POAG had undergone glaucoma drainage surgery. Although the glaucoma in these families appears to be pressure dependent, 2 individuals showed optic disc cupping before detected elevation in intraocular pressure. One family was of British origin, with a different background haplotype from the other 3 families from Greece or Macedonia, who shared a common haplotype. CONCLUSIONS: The GLC1A Thr377Met mutation is associated with POAG that, in the pedigrees studied, had a younger age at onset and higher peak intraocular pressure than in pedigrees with the more common Gln368STOP mutation. In addition, patients with glaucoma with the Thr377Met mutation were more likely to have undergone glaucoma drainage surgery.

Determination of full 13C isotopomer distributions for metabolic flux analysis using heteronuclear spin echo difference NMR spectroscopy.

13C-isotopomer labeling experiments play an increasingly important role in the analysis of intracellular metabolic fluxes for genetic engineering purposes. 13C NMR spectroscopy is a key technique in the experimental determination of isotopomer distributions. However, only subsets of isotopomers can be quantitated using this technique due to redundancies in the scalar coupling patterns and due to invisibility of the 12C isotope in NMR. Therefore, we developed and describe in this paper a 1H NMR spectroscopy method that allows to determine the complete isotopomer distribution in metabolites having a backbone consisting of up to at least four carbons. The proposed pulse sequences employ up to three alternately applied frequency-selective inversion pulses in the 13C channel. In a first application study, the complete isotopomer distribution of aspartate isolated from [1-13C]ethanol-grown Ashbya gossypii was determined. A tentative model of the central metabolism of this organism was constructed and used for metabolic flux analysis. The aspartate isotopomer NMR data played a key role in the successful determination of the flux through the peroxisomal glyoxylate pathway. The new NMR method can be highly instrumental in generating the data upon which isotopomer labeling experiments for flux analysis, that are becoming increasingly important, are based.

Short term effects of air pollution on emergency hospital admissions for respiratory disease: results of the APHEA project in two major cities in The Netherlands, 1977-89.

STUDY OBJECTIVE: To assess the short term relationship between air pollution and the daily number of emergency hospital admissions for respiratory disease. DESIGN: Data were analysed using autoregressive Poisson regression allowing for overdispersion and controlling for possible confounding factors such as seasonal and other chronological variables, meteorological factors, and influenza epidemics. SETTING: The two major cities in The Netherlands-Amsterdam (694,700 inhabitants) and Rotterdam (576,200 inhabitants). PARTICIPANTS AND MEASUREMENTS: Emergency hospital admissions for respiratory diseases, registered on a daily basis by the National Medical Registration, for the period 1977-89 were used. ICD-9 codes included were: respiratory (460-519), chronic obstructive pulmonary disease (490-492, 494, 496), and asthma (493). The mean (range) of the total daily number of admissions for these three classifications were as follows: 6.70 (0-23), 1.74 (0-9) and 1.13 (0-7) respectively in Amsterdam and 4.79 (0-19), 1.57 (0-9), and 0.53 (0-5) in Rotterdam. Air pollution measurements were provided by the National Institute of Public Health and Environmental Protection. In The Netherlands, air pollution is at a low to moderate ("summer type") or a low ("winter type") level. The levels in Amsterdam and Rotterdam did not differ much for the "summer type". For 1977-89 the mean (range) values of ozone (O3), the "summer type" pollutant (O3-8 h), were 86 (0-252) micrograms/m3 in Amsterdam and 82 (0-286) micrograms/m3 in Rotterdam. The mean (range) of the values "winter type", pollutant, sulphur dioxide (SO2-24 h), were 38 (0-381) micrograms/m3 in Amsterdam and 50 (1-379) micrograms/m3 in Rotterdam. For black smoke (BS-24 h), values were 14 (1-84) micrograms/m3 and 28 (1-144) micrograms/m3 respectively (1986-89). MAIN RESULTS: Ozone had a non-significant positive effect on the number of respiratory emergency admissions in summer in people aged > or = 65 years (relative risk for a 100 micrograms/m3 increase in O3-8 h of 1.127 (0.983, 1.292) in Amsterdam and a significant positive effect of 1.344 (1.097, 1.647) in 1977-81 in Rotterdam). Sulphur dioxide did not show any clear effects; in Amsterdam a significant negative effect was even found. The same was true for nitrogen dioxide in Amsterdam; in Rotterdam, however, nitrogen dioxide showed non-significant positive effects (RR 0.965, 1.342). Black smoke did not show any clear effects in Amsterdam; in Rotterdam it was positively but not significantly related to the number of admissions. CONCLUSIONS: The results show that the relation between short term air pollution and emergency hospital admissions is not always consistent at these rather low levels of daily hospital admissions and of air pollution.

Lafora-body disease with optic atrophy, macular degeneration and cardiac failure.

A 17-year-old boy was admitted to hospital in acute cardiac failure and psychosis. The clinical course, EEG records and tissue diagnosis, including biopsies of brain, skin, skeletal muscle, peripheral nerve and liver were compatible with Lafora-body disease (LBD). Unusual features were those of optic atrophy and macular degeneration, signs generally regarded as negative criteria for the diagnosis of this disease. We also present the findings on endomyocardial biopsy which was performed because cardiac failure as an early symptom of LBD has not been previously described. The patient died in status epilepticus a few months after discharge from hospital.

The problem of overlapping glaucoma families in the Glaucoma Inheritance Study in Tasmania (GIST).

The Glaucoma Inheritance Study in Tasmania (GIST) is a population survey of Australia's island state, Tasmania (population 450,000). Its aim is to find families with autosomal dominant, adult-onset, primary open angle glaucoma (POAG) suitable for genetic linkage analysis. POAG is relatively common, affecting around 3% of the Australian population. By finding the large families with POAG and identifying all the descendants in a captive population, it is possible that there may be overlap of different glaucoma pedigrees. Three of the first thirteen families in the study were composed of overlapping pedigrees. In one GIST family, GTas3, there has been intermarriage with other pedigrees with glaucoma on five occasions. The possibility of multiple genotypes was also reinforced by the inability to determine a single glaucoma phenotype in this family. When finding large families of POAG for linkage analysis, researchers must be aware of the risk of affected individuals inheriting their gene from the alternate parent. Thus, the alternate parents or their families must be examined, especially if the phenotype is atypical for the rest of the family.

In vivo 1H-NMR procedure to determine several rat cerebral metabolite levels simultaneously, undisturbed by water and lipid signals.

Methods developed for in vivo 1H-NMR spectroscopy are evaluated and applied using conscious rats. Good quality 1H-spectra of the brain are obtained using a surface coil and a spin echo pulse sequence with the binomial 1-1 and 2-2 water suppression pulses. However, comparing spectra from various rats with each other the water and lipid signals, which cause spectral overlap problems, may differ while the other spectral peaks agree well. Spatially one- and two-dimensional 1H spectroscopic imaging of the rat brain shows that the former signals stem from distinct spatial regions localized close to the rf coil. From a spectroscopic image, a spectrum over a limited spatial region is constructed in which the water signals are strongly reduced, the lipid signals are eliminated and lactic acid can be observed clearly simultaneously with other metabolites.