Translating ultrasound-mediated drug delivery technologies for CNS applications

Ultrasound enhances drug delivery into the central nervous system (CNS) by opening barriers between the blood and CNS and by triggering release of drugs from carriers. A key challenge in translating setups from in vitro to in vivo settings is achieving equivalent acoustic energy delivery. Multiple devices have now been demonstrated to focus ultrasound to the brain, with concepts emerging to also target the spinal cord. Clinical trials to date have used ultrasound to facilitate the opening of the blood-brain barrier. While most have focused on feasibility and safety considerations, therapeutic benefits are beginning to emerge. To advance translation of these technologies for CNS applications, researchers should standardise exposure protocol and fine-tune ultrasound parameters. Computational modelling should be increasingly used as a core component to develop both in vitro and in vivo setups for delivering accurate and reproducible ultrasound to the CNS. This field holds promise for transformative advancements in the management and pharmacological treatment of complex and challenging CNS disorders.

Encapsulation of the growth factor neurotrophin-3 in heparinised poloxamer hydrogel stabilises bioactivity and provides sustained release

Poloxamer-based hydrogels show promise to stabilise and sustain the delivery of growth factors in tissue engineering applications, such as following spinal cord injury. Typically, growth factors such as neurotrophin-3 (NT-3) degrade rapidly in solution. Similarly, poloxamer hydrogels also degrade readily and are, therefore, only capable of sustaining the release of a payload over a small number of days. In this study, we focused on optimising a hydrogel formulation, incorporating both poloxamer 188 and 407, for the sustained delivery of bioactive NT-3. Hyaluronic acid blended into the hydrogels significantly reduced the degradation of the gel. We identified an optimal hydrogel composition consisting of 20 % w/w poloxamer 407, 5 % w/w poloxamer 188, 0.6 % w/w NaCl, and 1.5 % w/w hyaluronic acid. Heparin was chemically bound to the poloxamer chains to enhance interactions between the hydrogel and the growth factor. The unmodified and heparin-modified hydrogels exhibited sustained release of NT-3 for 28 days while preserving the bioactivity of NT-3. Moreover, these hydrogels demonstrated excellent cytocompatibility and had properties suitable for injection into the intrathecal space, underscoring their suitability as a growth factor delivery system. The findings presented here contribute valuable insights to the development of effective delivery strategies for therapeutic growth factors for tissue engineering approaches, including the treatment of spinal cord injury.

Investigating the influence of ultrasound parameters on ibuprofen drug release from hydrogels

Hydrogels are promising ultrasound-responsive drug delivery systems. In this study, we investigated how different ultrasound parameters affected drug release and structural integrity of self-healing hydrogels composed of alginate or poloxamers. The effects of amplitude and duty cycle at low frequency (24 kHz) ultrasound stimulation were first investigated using alginate hydrogels at 2% w/v and 2.5% w/v. Increasing ultrasound amplitude increased drug release from these gels, although high amplitudes caused large variations in release and damaged the gel structure. Increasing duty cycle also increased drug release, although a threshold was observed with the lower pulsed 50% duty cycle achieving similar levels of drug release to a continuous 100% duty cycle. Poloxamer-based hydrogels were also responsive to the optimised parameters at low frequency (24 kHz, 20% amplitude, 50% duty cycle for 30 s) and showed similar drug release results to a 2.5% w/v alginate hydrogel. Weight loss studies demonstrated that the 2% w/v alginate hydrogel underwent significant erosion following ultrasound application, whereas the 2.5% w/v alginate and the poloxamer gels were unaffected by application of the same parameters (24 kHz, 20% amplitude, 50% duty cycle for 30 s). The rheological properties of the hydrogels were also unaffected and the FTIR spectra remained unchanged after low frequency ultrasound stimulation (24 kHz, 20% amplitude, 50% duty cycle for 30 s). Finally, high-frequency ultrasound stimulation (1 MHz, 3 W.cm^-2, 50% duty cycle) was also trialled; the alginate gels were less responsive to this frequency, while no statistically significant impact on drug release was observed from the poloxamer gels. This study demonstrates the importance of ultrasound parameters and polymer selection in designing ultrasound-responsive hydrogels.

0587 Convenience vs Accuracy: Negative Predictability of the Home Sleep Test in Clinical Practice

Introduction

Sleep apnea is a serious disorder associated with numerous health conditions. In clinical practice, providers order screening home sleep testing (HST) for obstructive sleep apnea (OSA); however, there is limited research about the negative predictive value (NPV) and false negative rate of this test. Providers may not understand HST limitations; therefore, what is the NPV and false negative rate in clinical practice?

Methods

A retrospective study of non-diagnostic HST is conducted in a Northeastern US rural community sleep clinic. The study population includes adult patients ≥ 18 years old who underwent HST from 2016-2019. The non-diagnostic HST result is compared to the gold standard, the patient’s nocturnal polysomnogram (NPSG). The results provide the NPV (true negative/total) and false negative (true positive/total) for the non-diagnostic HST.

Results

We identified 211 potential patients with a mean age of 43 years, of which 67% were female. Of those, 85% (n=179) underwent NPSG, with the others declining/delaying testing or lost to follow up. The non-diagnostic HST showed 15.6% NPV for no apnea using AHI<5 and 8.4% NPV using respiratory disturbance index (tRDI)<5. The false negative rate for AHI/tRDI was 84.4% and 91.6%, respectively. The AHI for positive tests ranged from 5-89 per hour (mean AHI 14.9/tRDI 16/hour), of which OSA was identified with an elevated AHI (≥5) ranging from 54.2% mild, 21.8% moderate, and 8.4% severe.

Conclusion

The high false negative rate of the HST is alarming. Some providers and patients may forgo NPSG after non-diagnostic HST due to a lack of understanding for the HST’s limitations. Knowing that the non-diagnostic HST is a very poor predictor of no sleep apnea will help providers advise patients appropriately for the necessity of the NPSG. The subsequent NPSG provides an accurate diagnosis and, therefore, an informed decision about pursuing or eschewing sleep apnea treatment.

Support

none

The Effect of Manufacturer on the Compounding of Omeprazole Suspensions and Their Stability Assessment

In New Zealand, there are no liquid formulations of omeprazole commercially available, therefore suspensions must be extemporaneously compounded from solid dosage forms for patients with swallowing difficulties. The funding for solid dosage forms of omeprazole changes frequently, often every one to two years, without consideration of the impact this may have when extemporaneously compounded liquid dosage forms are required. This study examined suspensions compounded from various solid dosage forms of omeprazole with the purpose of identifying suitable quality formulations and evaluating their chemical and physical stability. Six different solid dosage forms of omeprazole that are available in New Zealand, including capsules, tablets, and powder, were used to prepare 2-mg/mL suspensions in 8.4% w/v sodium bicarbonate solution. The suspensions were then assessed visually for quality and by quantifying sedimentation rate over 120 minutes. Two products, stored in amber bottles at either 4°C or 25°C, demonstrated acceptable quality over a 30-day period whilst monitoring physical and chemical stability on day 0, 7, 14, 20, and 30. Four of the formulated suspensions were deemed to be of poor quality due to either a lack of uniformity or rapid sedimentation, attributes that could lead to inaccurate dosing. Acceptable quality suspensions were prepared from Losec and Dr. Reddy's brands of omeprazole 20-mg capsules. For both brands, a change in color was observed after 20 days and 7 days when stored at 4°C and 25°C, respectively. Chemical stability was determined using a stability-indicating high-performance liquid chromatographic method, with >90% of the active remaining for 30 days when kept at 4°C, and 20 days when stored at 25°C. Not all brands are suitable for extemporaneously compounding omeprazole suspensions. Losec and Dr. Reddy's brands of capsules were suitable to prepare quality omeprazole suspensions. Omeprazole suspensions compounded from these products are stable for 20 days if stored at 4°C and protected from light.

Epithelial barrier dysfunction in lymphocytic colitis through cytokine-dependent internalization of claudin-5 and -8

BACKGROUND

Watery diarrhea is the cardinal symptom of lymphocytic colitis (LC). We have previously shown that colonic Na malabsorption is one of the major pathologic alterations of LC and found evidence for an epithelial barrier defect. On these grounds, this study aimed to identify the inherent mechanisms of this epithelial barrier dysfunction and its regulatory features.

METHODS

Epithelial resistance (R ^epi) was determined by one-path impedance spectroscopy and ³H-mannitol fluxes were performed on biopsies from sigmoid colon in miniaturized Ussing chambers. Tight junction proteins were analyzed by Western blot and confocal microscopy. Inflammatory signaling was characterized in HT-29/B6 cells. Apoptosis and mucosal surface parameters were quantified morphologically.

RESULTS

R ^epi was reduced to 53% and ³H-mannitol fluxes increased 1.7-fold in LC due to lower expression of claudin-4, -5, and -8 and altered subcellular claudin-5 and -8 distributions off the tight junction. TNFα and IFNγ could mimic subcellular redistribution in HT-29/B6 cells, a process which was independent on MLCK activation. Epithelial apoptosis did not contribute to barrier dysfunction in LC and mucosal surface area was unchanged.

CONCLUSIONS

Epithelial barrier dysfunction in LC occurs through downregulation of claudin-4, -5, and -8, and redistribution of claudin-5 and -8 off the tight junction, which contributes to diarrhea by a leak-flux mechanism. The key effector cytokines TNFα and IFNγ turned out to be the trigger for redistribution of claudin-5 and -8. Thus, alongside sodium malabsorption, leak-flux is yet another important diarrheal mechanism in LC.

Identification of maternal characteristics associated with the use of epidural analgesia

The present survey aims to identify predictors associated with the use of epidural analgesia (EA). Therefore, from October 2007 to June 2008, a survey was conducted in 193 pregnant women (mean age 31.7 years (SD 4.9); 64.8% primipara) attending a German general hospital with a specialisation in integrative medicine. Questionnaires, including Antonovsky's sense of coherence (SOC) were delivered antepartum. Delivery data were recorded within the hospital quality management programme. The adjusted odds ratio (OR) for EA use was significantly greater than one for women who had previously used EA (adjusted OR =4.1; CI: 1.03-16.31) and for the desire for a delivery without pain (adjusted OR =3.05; CI: 1.36-6.83). The likelihood of EA use decreased in multipara (adjusted OR =0.05; CI: 0.01-0.22). SOC was not found to be an independent predictor for EA use. However, women with high SOC more often preferred a delivery without EA (p for trend =0.037). In conclusion, first time labour, the desire for a delivery without pain and previous use of EA are independent predictors for the use of EA in labour. Further studies should clarify the predictive role of SOC in pregnancy.

Small scale boiling experiments using two-dimensional imaging with high-speed camera and optical coherence tomography

To investigate boiling processes, a test facility has been constructed, which allows the use of optical techniques for the detection of individual vapor bubbles. Demineralized water was used as working fluid at ambient pressure whereat temperature, flow rate and heat flux density can be varied. The growth of individual vapor bubbles was recorded by high-speed camera and analyzed by digital image processing (DIP). Optical coherence tomography (OCT) enabled the visualization of steam bubbles in cross-sections perpendicular to the heated surface.

Dynamics of S100B release into serum and cerebrospinal fluid following acute brain injury

High S100B serum levels are considered to reflect brain injury severity. However, the dynamics of S100B passage from the cerebral compartment into the blood remain unclear. We examined the temporal profile of S100B release into the cerebrospinal fluid (CSF) and blood in acute brain injury.In patients treated with ventricular drainage (subarachnoid hemorrhage, SAH, n = 23; traumatic brain injury, TBI, n = 19), we measured S100B levels in the serum and CSF. The Glasgow Coma Score (GCS) was assessed daily. Statistical analysis was performed by the Mann-Whitney rank sum test for group differences and by the Pearson correlation.In normal controls (n = 6), S100B levels in the serum (0.05 +/- 0.01 microg/L) comprised around 10% of the CSF concentration (0.66 +/- 0.08 microg/L). Following brain injury, S100B levels were significantly increased in the serum (p < 0.05 in SAH day 2-5, TBI day 1-8) and excessively increased in the CSF (p < 0.05 in SAH and TBI day 1-10). For the individual patient, there was no consistent correlation between S100B levels in serum or CSF and GCS. We therefore calculated the ratio of S100B serum/CSF. Following brain injury, the S100B passage from the CSF to the blood was significantly impaired. Further, higher ratios were correlated with better neurological function (p = 0.002).Because stimulated active S100B release may serve as a repair mechanism, a higher S100B serum/CSF ratio may contribute to neurological recovery.

Analysis of murine vascular function in vivo by optical coherence tomography in response to high-fat diet

In this study, we demonstrate the application of optical coherence tomography (OCT) as a contactless imaging technique to analyze vasodynamics in small blood vessels in vivo. The transluminal OCT imaging of vessels avoids micro traumata in the endothelium and circumvents surgical intervention. It can be performed in the intact perfused vessel and provides a new method to measure vascular function and dynamics in vivo. The resolution of 10 mum and the velocity of image acquisition are adequate to detect differences in the inner diameter, the maximal velocity, or the time to half-maximal diameter change of small vessels. We applied this new technology to study the vascular dynamics in small vessels of 6- and 20-week-old C57BL/6 mice in vivo. In addition, we determined by this technique the impact of a high-fat diet for 14 weeks on vascular function in 20-week-old animals. The diameter of the saphenous artery was increased under resting conditions, after vasoconstriction and after vasodilatation in 20-week-old animals on normal chow and high-fat diet, compared to 6-week-old animals. High-fat diet caused a significantly impaired vasoconstriction in the saphenous artery. The maximal velocity of diameter changes of the saphenous artery was determined by time-resolved OCT imaging. A significant reduction of this parameter was found during vasoconstriction in 20-week-old mice on high-fat diet, compared to 6-week-old animals. In conclusion, transluminal optical coherence tomography imaging is a novel and useful technique to analyze the impaired vasodynamics of small arteries in response to high-fat diet in vivo.

Changes in phosphorylation and dephosphorylation status of cytoskeleton and their regulator proteins in CD34+ stem cells after G-CSF stimulation and in AML

e22067

Background: The cytoskeleton is a cellular ‘scaffolding‘ or ‘skeleton‘ contained within the cytoplasm. It is a dynamic structure that maintains cell shape, enables cellular motion. ADF/cofilin is a family of actin-binding proteins which disassembles actin filaments. LIMK2 is phosphorylated and activated by ROCK, a downstream effector of Rho, and phosphorylates cofilin, inhibiting its actin-depolymerizing activity. Profilin binds to actin. At high concentrations, profilin prevents the polymerization of actin, whereas it enhances it at low concentrations. Cdk1 phosphorylates beta tubulin. In mitotic cells, phosphorylated tubulin is excluded from microtubules, being present in the soluble tubulin fraction. Stathmin/Op18 is a cytosolic phosphoprotein which regulates the dynamics of microtubules. The process of tumor proliferation and metastasis is characterized by high rates of mitosis and migration into distant tissues. In this study we investigated the expression of cytoskeleton proteins in native hematopoietic CD34+ stem cells from BM in comparison to mobilized peripheral blood stem cells (mPBSCs) from G-CSF stimulated donors as well as CD34+ cells from AML. Methods: An Auto-MACS (Miltenyi) and FACS Vantage SE cell sorter (Becton Dickinson) was used to process high enriched (>99%) CD34+ cells fractions from MNCs. Proteomics was performed with the Proteome Works System (BioRad). Protein identification was carried out by Q-TOF and ion trap mass spectrometer analyses. Phosphoproteins were detected with ProQ-Diamond stain and specific antibodies. Results: The comparative proteome analyses show that 1. actin, tubulin, vimentin are overexpressed and phosphorylated, 2. cofilin and profilin are unphosphorylated, and 3. Stathmin is overexpressed in G-CSF mobilized hematopoietic stem cells and in AML in his active ‘dephosphorylated‘ form. Conclusions: Highly enriched hematopoietic CD34+ cells are a prerequisite for the qualitative and quantitative phospho/proteome analyses. Our results show, that mobilized stem cells “in vivo” and AML cells increase cytoskeleton proteins expression and cause a complex phosphorylation status, which may explain the regulation of migration and metastasis.

No significant financial relationships to disclose.

Partonic pole matrix elements for fragmentation

A model-independent analysis of collinear three-parton correlation functions for fragmentation is performed. By investigating their support properties it is shown, in particular, that the so-called partonic pole matrix elements vanish. This sheds new light on the understanding of transverse single spin asymmetries in various hard semi-inclusive reactions. Moreover, it gives additional strong evidence for the universality of transverse-momentum-dependent fragmentation functions.

Signaling lymphocytic activation molecule (SLAM) is differentially expressed in human Th1 and Th2 cells

We have used a real-time quantitative RT-PCR technique (TaqMan, PE Biosystems) to identify genes that are differentially expressed by human polarised CD4(+) T cell subsets (Th1 or Th2). The goal was to test the feasibility of the detection method in profiling the expression of a set of marker genes important for Th1 and Th2 differentiation. We demonstrate that in polarised human Th1 cells signaling lymphocytic activation molecule (SLAM), a member of the immunoglobulin superfamily, is expressed at 7-25-fold higher levels than in Th2 cells. Along with SLAM, expression of the IL-12 receptor chain beta 2 (IL-12R beta 2) and the IFN-gamma receptor chain beta (IFN-gamma R beta) proved to be useful molecular markers indicating the state of T cell polarisation, as previously reported. Treatment with IL-12 increased SLAM mRNA expression in T cells by 3-4-fold, whereas a number of other cytokines including PDGF-BB, IFN-alpha A, IFN-alpha A/D, IFN-beta, IFN-gamma or IL-9 had no effect. Stimulating T cells by co-ligating CD3 and CD28 increased SLAM protein surface expression in both Th1 and Th2 cells. In conclusion, real-time RT-PCR detection was found to be an accurate, sensitive and highly reproducible method for fast profiling of mRNA expression in Th1 and Th2 cell subsets.

Initial uptake kinetics in human skin exposed to dilute aqueous trichloroethylene in vitro

In vitro uptake of 14C-labeled trichloroethylene (TCE) from dilute (approximately 5-ppb) aqueous solutions into human surgical skin was measured using accelerator mass spectrometry (AMS). We analyzed 105 breast-tissue samples obtained from three subjects, representing 27 separate exposure experiments conducted at approximately 20 degrees C for 0, 1, 5, 15, 30, or 60 min. The AMS data obtained positively correlate with (p approximately 0) and vary significantly nonlinearly with (p = 0.0094) exposure duration. These data are inconsistent (p approximately 0) with predictions made for TCE by a proposed U.S. Environmental Protection Agency (USEPA) dermal-exposure model, even when uncertainties in its recommended parameter values for TCE are considered, but are consistent (p = 0.17) with a 1-compartment model for exposed skin-surface tissue governed in vitro by a maximum effective permeability of K*p = 0.28 cm h-1 (+/- 7.0%) and a first-order rate constant of k1 = 1.2 h-1 (+/- 16%). The apparent compartment depth is estimated to be approximately 40-100 microns, i.e., to comprise much or all of the epidermis. In contrast, the USEPA model implies only negligible TCE penetration beyond SC during a 1-h exposure. The K*p estimate based on the 1-compartment model fit is consistent with estimates for TCE based on in vivo studies, which supports the hypothesis that the USEPA model underpredicts short-term dermal uptake of TCE from water. It is shown that for humans, this fit also implies that normalized total uptake of TCE from water by short-term dermal contact in vivo is predicted to be fK*p, where f is approximately 80% for longer normothermic exposures and approximately 95% during a brief hot shower or bath. This study illustrates the power of AMS to facilitate analyses of contaminant biodistribution and uptake kinetics at very low environmental concentrations.

Close proximity of c-erbA2 and c-erbA-beta genes on the short arm of chromosome 3

The common loss region on the short arm of chromosome 3 (3p) in human breast tumors harbors two members of the c-erbA receptor gene family, c-erbA2 and c-erbA-beta, both of which recognize a BamHI polymorphism in human genomic DNA. Analysis of lymphocyte DNAs from 50 normal individuals and lymphocyte DNAs from 50 normal individuals and lymphocyte and tumor DNAs from 116 breast cancer patients revealed identical genotypes (a/a, b/b or a/b) for both probes. Furthermore, deletion of the same allele (a/- or -/b) of c-erbA2 and c-erbA-beta was detected in 25% of the 66 breast tumors from patients with constitutionally heterozygous genotypes for both genes. No sequence homology was detected between the c-erbA2 and c-erbA-beta genes, suggesting a physical linkage between these two genes. Digestion of the genomic DNA with combinations of restriction enzymes and hybridization with c-erbA2, which is a genomic fragment, and c-erbA-beta, which is a cDNA clone, provide evidence that c-erbA2 and a region of the c-erbA-beta gene are physically contiguous on the short arm of chromosome 3 and are separated by no more than 1.8 kb of DNA sequences.

An antisense oligodeoxynucleotide that depletes RI alpha subunit of cyclic AMP-dependent protein kinase induces growth inhibition in human cancer cells

Enhanced expression of the RI alpha subunit of cyclic AMP-dependent protein kinase type I has been correlated with cancer cell growth. We provide evidence that RI alpha is a growth-inducing protein that may be essential for neoplastic cell growth. Human colon, breast, and gastric carcinoma and neuroblastoma cell lines exposed to a 21-mer human RI alpha antisense phosphorothioate oligodeoxynucleotide (S-oligodeoxynucleotide) exhibited growth inhibition with no sign of cytotoxicity. Mismatched sequence (random) S-oligodeoxynucleotides of the same length exhibited no effect. The growth inhibitory effect of RI alpha antisense oligomer correlated with a decrease in the RI alpha mRNA and protein levels and with an increase in RII beta (the regulatory subunit of protein kinase type II) expression. The growth inhibition was abolished, however, when cells were exposed simultaneously to both RI alpha and RII beta antisense S-oligodeoxynucleotides. The RII beta antisense S-oligodeoxynucleotide alone, exhibiting suppression of RII beta along with enhancement of RI alpha expression, led to slight stimulation of cell growth. These results demonstrate that two isoforms of cyclic AMP receptor proteins, RI alpha and RII beta, are reciprocally related in the growth control of cancer cells and that the RI alpha antisense oligodeoxynucleotide, which efficiently depletes the growth stimulatory RI alpha, is a powerful biological tool toward suppression of malignancy.

IRAOS: an instrument for the assessment of onset and early course of schizophrenia

Since Kraepelin's first description of dementia praecox in 1889 many data and theories have been published on the onset and course of schizophrenia. Until now studies on these topics had to rely on first admission data and on the subsequent course of the disease. However, first hospitalisation is preceded by a wide variety of patterns and duration of the early course. Items taken from the pre-admission phase of the disease are often incorrectly used as premorbid characteristics, understandably preceding the subsequent course and outcome of schizophrenia with high predictive power. In relation to our interest to study the beginning of schizophrenia, systematically, paying special attention to the age and gender distribution of true onset and the symptomatology and pattern of the early and later course, we developed an 'Interview for the Retrospective Assessment of the Onset of Schizophrenia (IRAOS)'. It allows an objective, reliable, and valid assessment of the symptoms, psychological impairments, demographic and social characteristics as well as the referring points in time of the early course of psychosis. The instrument is administered as a semi-structured interview with both the patient and a key informant. The obtained information is extended by a systematic examination of the clinician's case notes. Some results derived from an ongoing study on age and gender differences in onset and patterns of early course are added to demonstrate the use of the instrument.

A cDNA encoding a muscle-type tropomyosin cloned from a human epithelial cell line: identity with human fibroblast tropomyosin TM1

Tropomyosins (TM) expressed by human epithelial cells have only recently been characterized, and no sequence data for them has appeared. We cloned a cDNA encoding a high molecular weight, muscle-type TM from a LS174T human colon carcinoma epithelial cell cDNA library. On sequence analysis this cDNA (TMe1) was virtually identical to the previously reported sequence for human fibroblast TM1 encoded by the hTM beta gene. Expression of TM1/TMe1 mRNA and protein are low in epithelial cells compared with fibroblasts. The results indicate that cells of different developmental lineages (entodermal and mesodermal) can produce identical TM beta gene splice products while regulating expression of those transcripts in a lineage-specific way.

Cooperative effect of 8-Cl-cAMP and rhGM-CSF on the differentiation of HL-60 human leukemia cells

In HL-60 leukemia cells the site-selective cAMP analog, 8-Cl-cAMP, at a dose of 5 microM produced growth inhibition with no signs of toxicity, whereas granulocyte-macrophage colony stimulating factor (GM-CSF) exerted an early transient increase of cell proliferation which was followed by differentiation toward monocytes. 8-Cl-cAMP in combination with GM-CSF blocked the growth stimulation due to GM-CSF and demonstrated a synergistic effect on the differentiation of HL-60 cells. The early proliferative effect of GM-CSF was correlated with an increased expression of type I regulatory subunit of cAMP-dependent protein kinase (RI alpha). Treatment with an RI alpha antisense oligodeoxynucleotide suppressed the GM-CSF-inducible cell proliferation and differentiation. Conversely, an RII beta antisense oligodeoxynucleotide, which suppresses the RII beta and causes a compensatory increase in RI alpha level, greatly enhanced the early proliferative input and the differentiation induced by GM-CSF. These results provide an insight into the mechanism of action of GM-CSF and the rationale for a combination differentiation therapy with 8-Cl-cAMP and GM-CSF.

[Cellular immunity in dialysis patients using the lymphocyte transformation test (LTT) in comparison to conservatively treated patients with chronic terminal renal failure]

By means of the lymphocyte transformation test (LTT), using the mitogens phytohemagglutinin (PHA), concanavalin A (ConA), lipopolysaccharide (LPS) E. coli and the antigens tuberculin (PPD) and O-streptolysin, a contribution should be made for the judgment of the functional capacity of the immune system--in particular of the cellular immunity--in uraemia patients with and without dialysis therapy. In 33 patients with different duration of the dialysis (0.5 to 130 months) and 15 retention patients who were not yet treated by means of dialysis the LTT was controlled with stimulant agents mentioned above. In these cases was shown that dialysis patients managed metabolically regularly did not show a significant restriction of the cellular immunity in the LTT (PHA-stimulation over 0.55 transformed cells, con-A-stimulation over 0.37 transformed cells). The not dialysed patients with chronic uraemia showed a distinct diminution of the unspecific T-cell transformation by PHA and ConA, whereas the antigen-induced stimulation (PPD, O-streptolysin) was not disturbed in this case as well. In the two cases the B-cell transformation (on LPS) was not significantly disturbed. There was a good concordance with the clinical findings: scarcely general infects, no shunt infections, relatively many organ losses by rejection after transplantation in the dialysis patients. The not yet dialysed retention patients revealed clinically a higher inclination to an infect. There were no own experiences about the course after transplantation without preceding dialysis. It is discussed in how far also immunological investigations may play a role in the establishment of the optimum management of the dialysis, the moment of the beginning with the dialysis and for the "more individual preparation of the transplantation".

[Hemoperfusion therapy in severe suicidal digoxin poisoning]

Severe digoxin intoxications have a mortality rate of about 20%. Clinical course of intoxication, electrocardiographic changes as well as the behaviour of the plasma-digoxin concentration could closely be controlled on 4 patients after suicidal ingestion of potentially lethal dilanacin -new doses. In 3 patients a haemoperfusion treatment lasting 4 to 6 hours was performed. Clinical symptoms and existing disturbances of cardiac rhythm were clearly positively influenced under perfusion. The earlier the treatment was begun the more favourably appear the effects on the course of intoxication. After an at first benign picture of intoxication in the non-perfused female patient a comparatively distinct prolonged clinical and electrocardiographic symptomatology developed. Though the digoxin extraction established by computation fairly slightly imposes, this eliminated free digoxin fraction seems, nevertheless, to possess a considerable pharmacological and clinical importance. The adsorber material used showed well reproducible high clearance performances. During the haemoperfusion treatment in no case clinical complications were observed.

[Discontinuous plasma exchange with the conventional hemodialysis technic and blood cell centrifugation]

A conventional haemodialysis system, to which the patient is connected as for acute dialysis, forms the basis of the plasma substitution method. At each session around 2 litres of plasma were exchanges within 3 hours. Freshly frozen donor plasma was mainly used as the substitution solution. A total of 20 substitutions were carried out in 5 patients in a period of 7 months. The indications were: 3 x major mismatch in the ABO system before bone marrow transplantation, myasthenic crisis, violent attacks connected with lupus erythematosus with rapid development of renal insufficiency. The therapeutic goal of quickly eliminating immunopathogenetic proteins was achieved in all cases. It was possible to reduce the level of isoagglutinins, haemolysins, autoantibodies (myasthenia gravis) and immunity complexes (LE) effectively. The clinical course confirmed the excellent effectivity. There were no serious complications despite the serious primary diseases. Volume imbalances, changes of body temperature, precipitations of cryoglobulins, electrolyte disturbances or citrate intoxications were always well controllable thanks to the combination of plasma substitution and dialysis.

[Investigations on the utilisation of parenterally administered amino acids by premature and small-for-dates neonates. II. Investigations of elimination half life time, elimination constants, transfer and clearances of amino acids after short-time infusion of L-amino acid mixtures (author's transl)]

10 ml/kg body weight of a 5% standardized L-amino-acid-mixture was given within the first 25 days to 25 prematurely born infants of 32--37 weeks gestationale and 5 small-for-dates newborns. We studied the metabolic kinetics of these amino acids in the serum and calculated elimination half life time, elimination constants, clearance and transfer rates of the single amino acids. The results were correlated with sex, nutritional state and age. 5 additional experiments were performed with 3 prematurely born infants and 2 small-for-dates newborns. The following results were of special interests: 1. Nearly all amino-acids had half life times between 30 and 50 min. Ornithine and tryptophane were more (half life time: 70 and about 50 min, respectively) slowly eliminated, while arginine and glutamic acid had half life times of between 5 and 15 min. 2. There was no statistically significant differences between sexes. 3. Eutrophic prematures eliminated the amino acids much faster then the hypotrophic ones. 4. Hypotrophic premature infants showed slow elimination of nearly all amino acids compared with hypotrophic newborns. 5. The elimination of nearly all amino acids studied grew faster with increasing age. The most significant differences were registered between the 1st and 3rd weeks of life.