A biokinetic study of 209Po in man

Five adult volunteers participated in a biokinetic study of radioactive polonium. Portions of about 10 Bq of (209)Po were orally administrated to four of the volunteers in a single ingestion. The fifth volunteer ingested a daily amount of 53 mBq of 209Po for 243 d to study the time to achieve equilibrium between intake and excretion for protracted intakes. For the subjects ingesting single intakes of (209)Po complete sampling of urine and feces was subsequently collected the first few days upon the ingestion. The samples were processed with radiochemical extraction and analyzed with alpha spectrometry. In the study, the maximum daily excretion rates in feces were 18-50% of the ingested activity, observed within 3 d after intake. Regarding the urine excretion, the daily excretion peaked, on average, at 0.15-1% of the ingested activity within two days upon intake. These results indicate an average gastro-intestinal uptake fraction of 0.46±0.08, which agrees well with earlier biokinetic studies of polonium in man.

Remission maintenance in acute myeloid leukemia: impact of functional histamine H2 receptors expressed by leukemic cells

Post-consolidation immunotherapy with histamine dihydrochloride and interleukin-2 has been shown to improve leukemia-free survival in acute myeloid leukemia in a phase III trial. For this study, treatment efficacy was determined among 145 trial patients with morphological forms of acute myeloid leukemia as defined by the French-American-British classification. Leukemia-free survival was strongly improved in M4/M5 (myelomonocytic/monocytic) leukemia but not in M2 (myeloblastic) leukemia. We also analyzed histamine H(2) receptor expression by leukemic cells recovered from 26 newly diagnosed patients. H(2) receptors were typically absent from M2 cells but frequently expressed by M4/M5 cells. M4/M5 cells, but not M2 cells, produced reactive oxygen species that triggered apoptosis in adjacent natural killer cells. These events were significantly inhibited by histamine dihydrochloride. Our data demonstrate the presence of functional histamine H(2) receptors on human AML cells and suggest that expression of these receptors by leukemic cells may impact on the effectiveness of histamine-based immunotherapy.

Novel antigen design for the generation of antibodies to G-protein-coupled receptors

Antibodies are important tools for the study of G-protein-coupled receptors, key proteins in cellular signaling. Due to their large hydrophobic membrane spanning regions and often very short loops exposed on the surface of the cells, generation of antibodies able to recognize the receptors in the endogenous environment has been difficult. Here, we describe an antigen-design method where the extracellular loops and N-terminus are combined to a single antigen for generation of antibodies specific to three selected GPCRs: NPY5R, B2ARN and GLP1R. The design strategy enabled straightforward antigen production and antibody generation. Binding of the antibodies to intact receptors was analyzed using flow cytometry and immunofluorescence based confocal microscopy on A-431 cells overexpressing the respective GPCR. The antibody-antigen interactions were characterized using epitope mapping, and the antibodies were applied in immunohistochemical staining of human tissues. Most of the antibodies showed specific binding to their respective overexpressing cell line but not to the non-transfected cells, thus indicating binding to their respective target receptor. The epitope mapping showed that sub-populations within the purified antibody pool recognized different regions of the antigen. Hence, the genetic combination of several different epitopes enables efficient generation of specific antibodies with potential use in several applications for the study of endogenous receptors.

Abstract 4569: Cell death-inducing ICAM-1 antibody has broad and potent anti-myeloma activity in vivo

We previously developed combined target and drug discovery methodology enabling isolation of tumor cell death-inducing antibodies from the human antibody library n-CoDeR®. Among several antibodies targeting different tumor cell associated receptors with documented cell death-inducing properties, antibodies specific for intercellular adhesion molecule-1 (ICAM-1) – a receptor not previously associated with tumor cell death- were obtained.

We here characterize the ICAM-1 specific antibody BI-505 with respect to in vivo anti-tumor activity in different well-established tumor disease models, and explore mechanisms underlying its anti-tumor activity. We demonstrate in different tumor xenograft models that BI-505 is equally or more efficacious in preventing CD20 positive B cell tumor growth and in pro-longing tumor-bearing mouse survival compared to CD20 mAb Rituximab in vivo. Moreover, BI-505 showed significant anti-tumor activity against a panel of CD20 negative myeloma tumors in vivo, and BI-505 conferred enhanced mouse survival compared to the proteasome inhibitor bortesomib – approved for treatment of relapsed refractory multiple myeloma – in an experimental model of advanced multiple myeloma. Preliminary data indicate that the BI-505 epitope is highly expressed on myeloma cells in patients with multiple myeloma.

The differential in vitro and in vivo anti-tumor activities of BI-505 Fc-variants correlated with binding to recombinant human FcγRIIIa and mouse FcγRIV receptors, respectively. These differences could not be explained by altered antigen-binding properties as all Fc-variants retained near identical EC50 values for binding to recombinant or cell surface expressed ICAM-1 protein. These observations are consistent with cell death and FcγR-dependent anti-tumor immunity being important mechanisms underlying BI-505 therapeutic activity.

Collectively, our results demonstrate proof-of-principle for our human antibody based combined target and drug discovery methodology, and provide a rationale for further pre-clinical and clinical evaluation of BI-505 in the treatment of MM. An open multicenter phase I dose-escalation clinical trial with BI-505 in relapsed/refractory MM has recently started in the United States and Sweden.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4569. doi:10.1158/1538-7445.AM2011-4569

Deep brain stimulation in the treatment of depression

OBJECTIVE

To present the technique of deep brain stimulation (DBS) and to evaluate the studies conducted on DBS in the treatment of therapy-refractory major depressive disorder (MDD).

METHOD

A review of the literature on DBS in the treatment of MDD was conducted.

RESULTS

The results of DBS in MDD have been presented in 2 case reports and 3 studies of 47 patients operated upon in 5 different target areas. Positive effects have been presented in all studies and side effects have been minor. DBS in the nucleus accumbens resulted in a mean reduction of Hamilton depression rating scale (HDRS) of 36% after 1 year and 30% of the 10 patients achieved remission. DBS in the internal capsule/ventral striatum resulted in a reduction of 44% after 1 year, and at the last evaluation after in mean 2 years, 40% of the 15 patients were in remission. The 20 patients with subcallosal cingulated gyrus DBS had a reduction of HDRS of 52% after 1 year, and 35% were within 1 point from remission or in remission.

CONCLUSION

DBS is a promising treatment for therapy-refractory MDD. The published experience is, however, limited, and the method is at present an experimental therapy.

PBSC harvests individually optimized by using pre-collection CD34(+) values and on-line flow cytometric analysis of the mononuclear cell enrichment

BACKGROUND

We have investigated how the amount of blood processed during collection of PBSC affects the yield of CD34 cells.

METHODS

We first established a method of significantly increasing the enrichment of mononuclear cells (MNC), CD34(+) cells and granulocyte-macrophage progenitors (GM-CFU) by on-line flow cytometric (FCM) analysis of the leukocyte populations in the collect line. A total of 166 PBSC collections from 94 patients, were devided into five groups according to the blood volume processed: < 12 L of processed blood, 12-13L, 13-14L, 14-15L and > 15L.

RESULTS

When the yield of CD34(+) cells war compared between these groups, a positive correlation was seen (r=0.97) between the processed blood volume and the yield, expressed as a ratio between total number of CD34(+) cells in the harvest and the CD34(+) cell concentration in blood. This correlation can be used to estimate the volume that must be processed to exceed a specific target number of CD34(+) cells. The implications of these results on the need for one, two or more leukapheresis procedures in order to collect a sufficient amount of stem and progenitor cells for a given patient are discussed, i n relation to clinical logistics and the benefits for the patients.

DISCUSSION

PBSC harvest can be improved by individually-adjusted leukapheresis according to on-line FCM analysis and pre-harvest levels of CD34(+) cells and the processed blood volume can be used to predict the CD34(+) yield.

Western blot quantification of aggrecan fragments in human synovial fluid indicates differences in fragment patterns between joint diseases

OBJECTIVE

To develop a Western blot method for quantification of multiple aggrecan fragments in human synovial fluids (SFs).

METHOD

SF aggrecan fragments were prepared from knee healthy (reference), knee injury and arthritis subjects by CsCl gradient centrifugations collecting D1 fractions. Samples were analyzed by Western blot, using antibodies against the N-terminal epitope ARGS and the G3 domain, and fragments were quantified using a digital luminescence image analyzer.

RESULTS

The method had a coefficients of variation of 10-30%, and a high correlation (r(S)=0.86) with a corresponding enzyme-linked immunosorbent assay (ELISA). The SFs from reference, knee injured and arthritic subjects contained two major ARGS fragments, ARGS-SELE and ARGS-CS1, and three major G3 fragments (GRGT-G3, GLGS-G3 and AGEG-G3). Compared to the reference, the acute arthritis and acute joint injury groups had a 30-fold elevated concentration of ARGS fragments, and both groups had a higher proportion of the aggrecan in joint fluid as ARGS fragments compared to the other groups. The reference and chronic injury groups had an excess of ARGS-CS1 fragments over ARGS-SELE fragments, while subjects with acute arthritis or osteoarthritis had a more even distribution between these fragments.

CONCLUSIONS

We have developed a novel Western blot quantification method for quantification of SF aggrecan fragments which can differentiate fragments of different sizes sharing the same epitope. The anti-ARGS and anti-G3 quantitative Western blots provided information important for a better understanding of the proteolytic pathways in aggrecan breakdown, information that discriminates between different joint diseases, and may aid in identification of new biomarkers.

Biphenotypic bigenotypic lymphoma with simultaneous expression of PAX5/BSAP and B- and T-cell markers

Lymphomas are currently categorized according to their origin from a B or T lymphocyte. Immature and less commonly mature (peripheral) lymphomas may harbor rearrangements of both the B- and T-cell antigen receptor genes (dual genotype or bigenotype). Rarely, cells in lymphoma with a single genotype simultaneously express both B- and T-cell markers (biphenotypic lymphomas). We discuss the diagnostic and clinical implications in the case of a 42-yr-old female with a peripheral CD30+ lymphoma that displayed both characteristic B- and T-cell surface antigens and clonal rearrangement of B- and T-cell antigen receptor gene loci. Simultaneous nuclear expression of the transcription factor gene PAX5 suggested that this major driver of B-cell differentiation did not preclude expression of CD3epsilon, generally assumed to be a T-cell associated antigen.

Cholestatic liver disease in adults may be due to an inherited defect in bile acid biosynthesis

BACKGROUND

An increasing number of treatable inborn errors of bile acid synthesis have been described, primarily in infants with severe cholestatic liver disease.

RESULTS

The present patient, whose two older siblings had died from progressive cholestatic liver disease, developed neonatal cholestasis and rickets but recovered during the childhood years and follow-up was terminated at 12 years of age. The patient presented again at 26 years of age with jaundice and pathological liver function tests. This was normalized upon treatment with ursodeoxycholic acid. Electrospray mass spectrometry of urine showed predominance of unsaturated bile acids, characteristic of 3beta-hydroxy-Delta5-C27-steroid dehydrogenase/isomerase (HSD3B7) deficiency. The activity of HSD3B7 in cultured fibroblasts was less than 5% of normal. A single homozygous mutation was found in exon 4 leading to an amino acid exchange (S162R) and loss of enzyme activity.

CONCLUSION

This case illustrates that infants with an inherited absence of HSD3B7 may survive the neonatal period of life and childhood without treatment with bile acids. A low level of sulphation of the abnormal trihydroxy bile acid formed as a result of enzyme deficiency may be of importance for survival. The possibility that liver disease presenting in the adult may be due to a mutation in the HSD3B7 gene should be considered, especially in cases with familial occurrence of liver disease and earlier periods of liver dysfunction.

Unique patient with cerebrotendinous xanthomatosis. Evidence for presence of a defect in a gene that is not identical to sterol 27-hydroxylase

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder believed to be exclusively caused by mutations in the CYP27A1 gene coding for the enzyme sterol 27-hydroxylase. Common findings in CTX are tendon xanthomas, cataracts and progressive neurological dysfunction. Here, we characterize an adult female patient with tendon xanthomas and classic biochemical findings of CTX (i.e. high levels of bile alcohols and cholestanol and extremely low levels of 27-hydroxycholesterol in plasma). Additionally, sterol 27-hydroxylase activity in cultured monocyte-derived macrophages from this patient was <5% of normal. Sequencing the CYP27A1 gene uncovered that the patient is heterozygous for two previously undescribed base substitutions in exon 8, C478A and C479A, which are expected to affect the haeme-binding domain of the enzyme. When expressed in HEK293 cells, the corresponding protein had only 8% of normal enzymatic activity. No other mutation was found in the open reading frame of the CYP27A1 gene, intron-exon boundaries or in the 5'-untranslated region up to 5000 bp distal to the translational start site. Sequencing mRNA isolated from leucocytes from the patient revealed a 1 : 1 ratio of mutated and nonmutated species, with total mRNA levels that were not significantly different from the controls. It is concluded that the patient is heterozygous for two mutations affecting one allele of the CYP27A1 gene and with at least one additional yet undefined gene that is of critical importance for the activity of sterol 27-hydroxylase.

Storage of buffy-coat-derived platelets in additive solutions at 4 °C and 22 °C: flow cytometry analysis of platelet glycoprotein expression

BACKGROUND

The aim of our in vitro study is to compare the effects on platelet membrane glycoproteins that play an important role in the main functions of platelets, when platelets are stored for a period of 21 days at 4 degrees C or 22 degrees C.

STUDY DESIGN AND METHODS

Platelet concentrates (PC) were prepared from pooled buffy-coats (BC) for paired studies (total eight pools from 80 BCs) by using the OrbiSac system. We divided each pool into two PCs and stored them at 4 degrees C or 22 degrees C.

RESULTS

The activation marker CD62 remained almost unchanged during storage in all units. The expression of CD63 was higher in PCs stored at 22 degrees C than in those stored at 4 degrees C. No significant difference in CD41 expression was detected over time. The expression of CD42b declined during storage and even more in PCs stored at 4 degrees C until day 21 [day 14: mean flourscence intensity: 32.5 +/- 13.1 vs. 46.5 +/- 19.1], but the percentage of platelets expressing CD42b remained high in platelets stored at 4 degrees C, but gradually decreased at 22 degrees C (day 14: 95.0 +/- 1.5 vs. 59.0 +/- 9.9). Storage at 4 degrees C reduced the rate of glycolysis and maintained the pH better after day 10 than in PCs stored at 22 degrees C (day 14: 7.009 +/- 0.067 vs. 7.233 +/- 0.125). The concentration of regulated upon activation of normal T-cells expressed and secreted was higher in PCs stored at 22 degrees C than at 4 degrees C (day 7: 414.7 +/- 32.3 vs. 49.6 +/- 19.0). No response to extent of shape change and no swirling were detected at 4 degrees C.

CONCLUSION

Platelets stored at 4 degrees C retain their in vitro characteristics better than those stored at 22 degrees C, except for parameters that reflect changes in shape. Storage at 4 degrees C is not associated with an increased expression of glycoprotein (GpIb, GpIIb/IIIa) and platelet activation markers (CD62p and CD63) as compared with storage at 22 degrees C.

Neutrophil elastase sorting involves plasma membrane trafficking requiring the C-terminal propeptide

The primary granules/secretory lysosomes of neutrophils store mature neutrophil elastase (NE) as a luminal protein after proteolytic removal of N-terminal and C-terminal pro-peptides from a proform of NE. The N-terminal pro-peptide prevents premature activation that might be toxic to the cell, but the C-terminal pro-peptide has no defined function. In this study, we investigated the role of the C-terminal pro-peptide in trafficking of NE by expressing, in rat basophilic leukemia (RBL) cells, both wild-type NE and the mutant NE/Delta248-267, which lacks the C-terminal pro-peptide. Both transfected proteins were found to be targeted to secretory lysosomes. In addition, results from antibody ligation and cell-surface biotinylation indicated that proform of NE was targeted to the plasma membrane, and then subjected to endocytosis. The results were supported by the detection of targeting of the proform to the plasma membrane followed by internalization both in RBL cells and normal granulopoietic precursor cells. Targeting of NE to the plasma membrane required the C-terminal pro-peptide as NE/Delta248-267 expressed in RBL cells bypassed plasma membrane trafficking. Our results indicate targeting of a population of NE to the plasma membrane and internalization dependent on the C-terminal NE pro-peptide.

Determination of intrathyroidal iodine by X-ray fluorescence analysis in 60- to 65-year olds living in an iodine-sufficient area

OBJECTIVES

X-ray fluorescence (XRF) is a non-invasive method for determining the iodine content of the thyroid gland in vivo. In spite of the obvious clinical value of such a method in situations of iodine deficiency or iodine overload, the method has not so far been widely used. The objective was to investigate the applicability of the XRF method in a larger number of subjects.

DESIGN AND SUBJECTS

The study comprised 37 individuals, aged 60-65 years, who had spent their entire life with iodine supplementation through iodinated table salt. Individuals with (previous) thyroid disease were excluded. The individual thyroid function had previously been evaluated by measurements of thyroid-related hormones, thyroid volume and 131-Iodine (131I) uptake which indicated a sufficient iodine intake of the population in the area. Iodine in the right thyroid lobe in each subject was examined using XRF.

RESULTS

The mean thyroid iodine concentration was 0.4 mg mL(-1), corresponding to a mean total iodine content of 5.2 mg (range 0.9-20.2). There was a pronounced difference between individuals. No correlation was found between iodine concentration and 131I uptake or thyroid volume. Neither was iodine content and 131I uptake correlated.

CONCLUSIONS

In a population living under iodine-sufficient conditions, a large variation of iodine stored in the thyroid is compatible with euthyroidism. Determination of the iodine pool by XRF investigation is feasible in a clinical setting and the method offers a unique possibility to study the intrathyroidal iodine pool in subjects with thyroid disease. The low radiation dose enables the use of the method in pregnant women and also in young individuals.

Granule targeting of soluble tumor necrosis factor (TNF) receptor expressed during granulopoietic maturation in murine bone marrow cells

In this experiment, we explored the potential of secretory lysosomes of hematopoietic cells to act as vehicles for immunomodulatory protein delivery at an inflammation site. We investigated whether exogenous soluble TNF-receptor 1 (sTNFR1) could be expressed in primary hematopoietic progenitor cells and become targeted for storage and secretion during granulopoietic differentiation. An sTNFR1 construct with a transmembrane domain (tm) and a cytosol sorting signal (Y) taken from CD63, was retrovirally transduced to lineage-negative murine hematopoietic bone marrow stem/progenitor cells. This process was followed by cytokine-driven granulopoietic maturation. The sTNFR1-tm-Y was found to be synthesized in precursor cells and to persist in mature granulocytes and monocytes/macrophages. Immunofluorescence-localization studies showed a granule pattern of sTNFR1-tm-Y in both precursor and mature granulocytes and secretion to phagosomes after ingestion of bacteria. Immunoelectron microscopy revealed co-localization between the sTNFR1-tm-Y and the primary (azurophil) granule marker myeloperoxidase. Collectively, our results demonstrated granule targeting, storage, and secretion of exogenous sTNFR1-tm-Y constitutively expressed during normal granulopoietic differentiation. These findings support the concept of using storage organelles of circulating hematopoietic cells as vehicles for targeting sites of inflammation with immunoregulatory agents.

Southern Ocean sea-ice extent, productivity and iron flux over the past eight glacial cycles

Sea ice and dust flux increased greatly in the Southern Ocean during the last glacial period. Palaeorecords provide contradictory evidence about marine productivity in this region, but beyond one glacial cycle, data were sparse. Here we present continuous chemical proxy data spanning the last eight glacial cycles (740,000 years) from the Dome C Antarctic ice core. These data constrain winter sea-ice extent in the Indian Ocean, Southern Ocean biogenic productivity and Patagonian climatic conditions. We found that maximum sea-ice extent is closely tied to Antarctic temperature on multi-millennial timescales, but less so on shorter timescales. Biological dimethylsulphide emissions south of the polar front seem to have changed little with climate, suggesting that sulphur compounds were not active in climate regulation. We observe large glacial-interglacial contrasts in iron deposition, which we infer reflects strongly changing Patagonian conditions. During glacial terminations, changes in Patagonia apparently preceded sea-ice reduction, indicating that multiple mechanisms may be responsible for different phases of CO2 increase during glacial terminations. We observe no changes in internal climatic feedbacks that could have caused the change in amplitude of Antarctic temperature variations observed 440,000 years ago.

Reactivation of latent Epstein Barr virus infection induces remission of splenic lymphoma with villous lymphocytes

Splenic lymphoma with villous lymphocytes (SLVL) is a rare, slowly progressing, lymphoproliferative disease of B-cell origin. Treatment aimed at cure or remission is limited, and spontaneous remission has not been described. We report on a patient who after 4 years with untreated SLVL developed symptoms of mononucleosis and was found to have reactivation of latent Epstein-Barr virus (EBV) infection. During recovery from the EBV infection, complete remission from SLVL developed and lasted for 3 years, suggesting that the EBV infection induced an immune response that caused the SLVL remission.

Biosynthesis, processing, and sorting of human myeloperoxidase

Exclusively synthesized by normal neutrophil and monocyte precursor cells, myeloperoxidase (MPO) functions not only in host defense by mediating efficient microbial killing but also can contribute to progressive tissue damage in chronic inflammatory states such as atherosclerosis. The biosynthetic precursor, apoproMPO, is processed slowly in the ER, undergoing cotranslational N-glycosylation, transient interactions with the molecular chaperones calreticulin and calnexin, and heme incorporation to generate enzymatically active proMPO that is competent for export into the Golgi. After exiting the Golgi the propeptide is removed prior to final proteolytic processing in azurophil granules, resulting in formation of a symmetric MPO homodimer linked by a disulfide bond. Some proMPO escapes granule targeting and becomes constitutively secreted to the extracellular environment. Although the precise mechanism is unknown, the pro-segment is required for normal processing and targeting, as propeptide-deleted MPO precursor is either degraded or constitutively secreted. Characterizing the molecular consequences of naturally occurring mutations that cause inherited MPO deficiency provides unique insight into the structural determinants of MPO involved in biosynthesis, processing and targeting.