Bimodal regulatory effect of melittin and phospholipase A2-activating protein on human type II secretory phospholipase A2

Melittin and phospholipase A2-activating protein (PLAP) are known as efficient activators of secretory phospholipase A2(sPLA2) types I, II, and III when phospholipid liposomes are used as substrate. The present study demonstrates that both peptides can either inhibit or activate sPLA2 depending on the peptide/phospholipid ratio when erythrocyte membranes serve as a biologically relevant substrate. Low concentrations of melittin and PLAP were observed to inhibit sPLA2-triggered release of fatty acids from erythrocyte membranes. The inhibition was reversed at melittin concentrations above 1 microM. PLAP-induced inhibition of sPLA2 persisted steadily throughout the used concentration range (0-150 nM). The two peptides induced a dose-dependent activation of sPLA2 at low concentrations, followed by inhibition when model membranes were used as substrate. This opposite modulatory effect on biological membranes and model membranes is discussed with respect to different mechanisms the interaction of the regulatory peptides with the enzyme molecules and the substrate vesicles.

Xenoendocrine disrupters-tiered screening and testing: filling key data gaps

The US Environmental Protection Agency (EPA) is developing a screening and testing program for endocrine disrupting chemicals (EDCs) to detect alterations of hypothalamic-pituitary-gonadal (HPG) function, estrogen (ER), androgen (AR) and thyroid hormone synthesis and AR and ER receptor-mediated effects in mammals and other animals. High priority chemicals would be evaluated in the Tier 1 Screening (T1S) battery and chemicals positive in T1S would then be tested (Tier 2). T1S includes in vitro ER and AR receptor binding and/or gene expression, an assessment of steroidogenesis and mammalian (rat) and nonmammalian in vivo assays (Table 1). In vivo, the uterotropic assay detects estrogens and antiestrogens, while steroidogenesis, antithyroid activity, (anti)estrogenicity and HPG function are assessed in a 'Pubertal Female Assay'. (Anti-) androgens are detected in the Hershberger Assay (weight of AR-dependent tissues in castrate-immature-male rats). Fish and amphibian assays also are being developed. The fathead minnow assay can identify EDCs displaying several mechanisms of concern, including AR and ER receptor agonists and antagonists and inhibitors of steroid hormone synthesis. An amphibian metamorphosis assay is being developed to detect thyroid-active substances. Several alternative mammalian in vivo assays have been proposed. Of these, a short-term pubertal male rat assay appears most promising. An in utero-lactational screening protocol also is being evaluated. For Tier 2, the numbers of endocrine sensitive endpoints and offspring (F1) examined in multigenerational tests need to be expanded for EDCs. Consideration should be given to tailoring T2, based on the results of T1S. Tier 1 and 2 also should examine relevant mixtures of EDCs. Toxicants that induce malformations in AR-dependent tissues produce cumulative effects even when two chemicals act via different mechanisms of action.

[Stress fractures in athletes]

Stress fractures may pose a diagnostic dilemma for radiologists since they are sometimes difficult to demonstrate on plain films and may simulate a tumour. They were first described in military personnel and professional athletes. Recently, there is an increasing incidence in the general population due to increasing sportive activities. Stress fractures occur most often in the lower extremities, especially in the tibia, the tarsal bone, the metatarsal bone, the femur and the fibula. In the upper extremities, they are commonly found in the humerus, the radius and the ulna. Some fractures of the lower extremities appear to be specific for particular sports, for example, fractures of the tibia affect mostly distance runners. Whereas stress fractures of the upper extremities are generally associated with upper limb-dominated sports. A correct diagnosis requires a careful clinical evaluation. The initial plain radiography may be normal. Further radiological evaluation could be performed by means of computerised tomography, magnetic resonance imaging and bone scanning. The latter two techniques are especially helpful for establishing a correct initial diagnosis.

Health consequences of an intravenous injection of metallic mercury

BACKGROUND

Mercury poisoning presents a variety of clinical pictures depending on chemical structure, the route of exposure, amount absorbed and individual factors. Thus, an injection of metallic mercury can be considered relatively harmless in contrast to inhalation of mercury vapor. Injection of elemental mercury is rare, and a total of only 78 cases have been reported in the literature over the period 1923-2000.

CASE REPORT

We report a suicide attempt by intravenous injection of approximately 8 g metallic mercury. By X-ray examination widespread multiple mercury shadows were visible in the whole lung and also in the subcutaneous region of the cubital fossa, the small pelvis and the right hypogastrium. Mercury excretion after treatment with 2,3-dimercaptopropane-1-sulfonate (DMPS) was significantly higher than in occupationally exposed workers.

CLINICAL SYMPTOMS

The patient showed symptoms typical of acute mercury intoxication, including gastroenteritis, ulceromembranous colitis and stomatitis mercuralis. No biochemical abnormalities in hepatic or renal function occurred, despite the persistence of metallic densities in the body. The patient's lung function was normal. The patient transitionally developed erethismus and tremor mercuralis. After 1 month of DMPS treatment, the mercury levels in blood were still high and the tremor was persistent. Three years after the suicide attempt the surgical removal of residual mercury in the left fossa cubitalis was performed. The extirpation of residual mercury was successful in cutting the mercury levels to almost half. After the operation the patient showed no symptoms of chronic mercury intoxication.

CONCLUSIONS

Since only 1 mg of mercury per day could be removed with DMPS treatment, it can be calculated, that it would take about 8,000 daily treatments to remove a total of 8 g solely by DMPS. Although DMPS itself does not dissolve the metallic deposits, it may considerably reduce the blood level of mercury and may therefore mitigate clinical symptoms, albeit transitorily. We therefore recommend that in cases of symptomatic metallic mercury injections, where the mercury cannot be removed by surgery, the patient's condition should be managed by repeated long-term DMPS treatment in order to control blood mercury levels.

Tests of biocompatibility of alpha-tocopherol with respect to the use as a stabilizer in ultrahigh molecular weight polyethylene for articulating surfaces in joint endoprostheses

To inhibit the oxidation in vivo of hip-cups made of ultrahigh molecular weight polyethylene (UHMW-PE), the natural antioxidant alpha-tocopherol was added to the polymer. The added alpha-tocopherol may however undergo chemical transformations during manufacturing and sterilization by gamma-irradiation of hip-cups which may differ from human metabolism. Therefore, the question of the biocompatibility of the respective transformation products was investigated on test samples, which were prepared under the same conditions as applied for the production and sterilization of hip-cups. Thin plates (25 x 18 x 2 mm(3)) were fabricated out of test samples to investigate the cytotoxic activity according to EN 30993-5. In cytotoxicity testing, proliferation, mitochondrial activity and membrane integrity were not influenced by the material. In contrast, cell adhesion and cell spreading were diminished as shown with hemalum staining. In order to investigate the genotoxicity, the alpha-tocopherol and its transformation products were extracted from test specimens by n-heptane at 185 degrees C under nitrogen atmosphere. Then the n-heptane was evaporated in vacuo and the remaining alpha-tocopherol and its transformation products were dissolved in DMSO. The genotoxicity of this extract was then tested by the Ames-test according to DIN UA 12 (1995), which showed no indication for genotoxic activity.

A multicentre evaluation of a new filtration protocol for leucocyte depletion of high-haematocrit red blood cells collected by an automated blood collection system

BACKGROUND AND OBJECTIVES

A multicentre trial was set up to evaluate the performance of a new leucodepletion protocol.

MATERIALS AND METHODS

Filtration at high haematocrit was started during collection of red blood cell (RBC) products by apheresis with Trima. SAG-M was added after filtration through the filter. Haematocrits and haemoglobin of the filtered RBCs were measured. Residual leucocytes were determined by Nageotte counting.

RESULTS

One-hundred and forty seven procedures were carried out. The haematocrit and haemoglobin contents were 57.3 +/- 3.0% and 55.1 +/- 4.3 g/unit, respectively. All products showed low residual leucocyte levels (< or = 0.75 x 106/unit; 99.31% < 1 x 106).

CONCLUSION

Immediate, on-line, high-haematocrit filtration of red cells collected on Trima resulted in leucoreduced RBCs, which met the AABB and Council of Europe criteria.

Examination of the suitability of alpha-tocopherol as a stabilizer for ultra-high molecular weight polyethylene used for articulating surfaces in joint endoprostheses

The lifetime of articulating surfaces in joint endoprostheses made of ultra-high molecular weight polyethylene (UHMW-PE), especially of UHMW-PE-cups of hip-endoprostheses, is usually limited to 10-15 years due to material failure as a result of oxidation of the UHMW-PE in vivo. In this study the suitability of the natural antioxidant alpha-tocopherol (vitamin E) as a stabilizer for UHMW-PE in these applications was investigated. Specimens with 0.1%, 0.2%, 0.4% and 0.8% w/w alpha-tocopherol as well as unstabilized samples were sintered and sterilized with gamma-rays at 25 kGy in accordance with standard processing methods of cups for total hip-endoprostheses. These specimens were aged in pure oxygen at 70 degrees C and 5 bar as well as in aqueous H2O2 at 50 degrees C. The degree of oxidation was observed by means of FTIR-spectroscopy, DSC analysis and mechanical testing. The FTIR-measurements showed that alpha-tocopherol can prolong the lifetime of UHMW-PE in an oxidative environment by a factor of more than 2.5. In the mechanical tests no embrittlement could be observed with the stabilized samples. A comparison with the standard antioxidant system Irganox 1010/Irgafos 168 (Ciba-Geigy, Switzerland) was carried out and revealed that alpha-tocopherol can even exceed the stabilization effect of this widely-used antioxidant system.

Is the Zona pellucida thickness of metaphase-II oocytes in an IVF/ICSI program influenced by the patient's age?

Zona pellucida (Z.p.) thickness is believed to be considerably influenced by hormonal stimulation. Assessments of the influence of the patient's age on Z.p. thickness have been at variance. In our study we wanted to investigate, among several other parameters, the age of the patient as a possible factor influencing Z.p. thickness. Prior to intracytoplasmatic sperm injection (ICSI) we determined the mean thickness of the Z.p. of 843 metaphase-II oocytes from 100 patients, which had been obtained after ovarian stimulation in an in vitro fertilization (IVF)/ICSI program. The mean thickness of the Z.p. was significantly positively correlated with the age of the patient (p = 0.000, r = 0.129). When the intraindividual mean values of Z.p. thickness (n = 100) were used, a positive correlation with age (p = 0.174, r = 0.137) remained. However, this correlation was no longer significant. It is concluded that, beside other factors, a thicker Z.p. could be responsible for the possibly lower fertilization rate of older patients in a conventional IVF program.

Does carditis have two different etiologies?

Carditis has become the subject of much study and discussion, although its etiology is still controversial. We wished to study the prevalence and possible pathogenetic mechanisms of carditis in a well-defined group of patients. In 664 patients biopsies were taken distal to the squamocolumnar junction (SCJ) and from the endoscopically defined cardia (2 cm below proximal margin of gastric folds). Specimens were stained with hematoxylin and eosin, Alcian blue, and modified Giemsa. Type of mucosa, inflammatory and metaplastic changes, and presence of Helicobacter pylori (Hp) were graded. Most of the patients had a normal appearing SCJ on endoscopy; 19.3% had short columnar segments (1-3 cm). In the first group cardiac/mixed mucosa was found in 71.9% of SCJ biopsies, and carditis (90.6%) was associated with Hp. In the second group, cardiac/mixed mucosa was present in 80.5%. There was a trend for an association between carditis (87.4%) and reflux esophagitis and hiatal hernia. Biopsies from the endoscopically defined cardia rarely contained cardiac/mixed mucosa (12.6%). These findings suggest two etiologies for carditis. In a normal-appearing SCJ carditis is associated with Hp, whereas in an irregular SCJ with short columnar segments/tongues carditis is associated with features of gastroesophageal reflux.

Species analysis of metallothionein isoforms in human brain cytosols by use of capillary electrophoresis hyphenated to inductively coupled plasma-sector field mass spectrometry

A new approach for the speciation of metallothioneins (MT) in human brain cytosols is described. The analysis is performed by application of a newly developed coupling of capillary electrophoresis (CE) with inductively coupled plasma-sector field mass spectrometry (ICP-SFMS). Isoforms of metallothioneins are separated from 30-100 microliter sample volumes by CE and the elements Cu, Zn, Cd, and S are detected by use of ICP-SFMS. The extraction of cytosols is the first step in the analytical procedure. Tissue samples from human brain are homogenized in a buffer solution and submitted to ultra-centrifugation. The supernatant is defatted and the cytosol pre-treatment is optimized for CE separation by matrix reduction. The buffer concentration and pH used for capillary electrophoretic separation of metallothionein from rabbit liver were optimized. CE with ICP-MS detection is compared to UV detection. In the electropherograms obtained from the cytosols three peaks can be assigned to MT-1, MT-2, and MT-3. As an additional method, size-exclusion chromatography (SEC) is applied. Fractions from an SEC separation of the cytosol are collected, concentrated, and then injected into the CE. The detection of sulfur by ICP-SFMS (medium resolution mode) and quantification by isotope dilution have also been investigated as a new method for the quantification of MT isoforms. The analytical procedure developed has been used for the first time in comparative studies of the distributions of MT-1, MT-2, and MT-3 in brain samples taken from patients with Alzheimer's disease and from a control group.

CD44 mediates constitutive type I receptor signaling in cervical carcinoma cells

OBJECTIVE

The CD44 transmembrane glycoprotein family has been implicated in the growth and metastasis of numerous human cancers. CD44 may function in some cells through interactions with type I receptor tyrosine kinases, including erbB2. Here, we tested whether CD44 interacts with erbB2 and another type I receptor, the epidermal growth factor receptor (EGFR), in human cervical carcinoma tissues and cell lines and whether these interactions influence erbB2 signaling.

METHODS

CD44, EGFR, and erbB2 colocalization were examined in 36 pT1b-pT2b cervical cancer cases and in the CaSki and SiHa cervical carcinoma cell lines by immunohistochemistry and laser scanning confocal microscopy. The role of CD44-EGFR-erbB2 interactions in erbB2 signaling was examined by immunoprecipitation and using antisense CD44 oligonucleotides.

RESULTS

CD44, erbB2, and EGFR coexpression and colocalization were observed in 42% (15/36) of cervical carcinoma cases and in both cervical carcinoma cell lines. Colocalization occurred to an equivalent extent in all tumor grades examined. CD44 coimmunoprecipitated with erbB2 and EGFR in cervical carcinoma cell lysates, indicating that these proteins interact with each other. Reduction of CD44 expression inhibited constitutive erbB2 activity. High CD44 expression was linked to EGFR activity using dominant negative EGFR, suggesting that type I receptors may autoregulate their activity in these cells.

CONCLUSIONS

Our data indicate that CD44 can mediate type I receptor function in cervical carcinoma cells that overexpress both CD44 and either erbB2 or EGFR and suggest a novel mechanism by which these proteins may contribute to cervical carcinoma tumor growth and metastasis.

Prolonged measurement of lower oesophageal sphincter function in patients with intestinal metaplasia at the oesophagogastric junction

BACKGROUND AND AIMS

It has been shown that gastro-oesophageal reflux plays a role in the pathogenesis of intestinal metaplasia (IM) limited to the oesophagogastric junction (OGJ), similar to the pathogenesis of IM in long segments of columnar lined oesophagus. The aim of this study was to examine lower oesophageal sphincter (LOS) function by means of prolonged recording in patients with IM limited to a normal appearing OGJ.

PATIENTS AND METHODS

Eighteen patients with IM at the OGJ (five females, 13 males; mean age 55.4 years) and 22 patients without IM (nine females, 13 males; mean age 53.9 years) underwent conventional stationary oesophageal manometry. Thereafter, seven hour water perfused manometry with simultaneous pH measurement (probe 5 cm proximal to the LOS) was performed. Swallowing was monitored with a pharyngeal sidehole and LOS pressure was recorded with a Dent sleeve. Patients were studied in the fasted state (three hours) and after a standardised meal (four hours). LOS pressure was analysed using customised software, and the incidence of reflux episodes (pH <4 for at least five seconds) and transient LOS relaxations (TLOSRs) were examined. TLOSRs were judged to be accompanied by reflux if a decrease of 1 pH unit occurred during relaxation.

RESULTS

Patients with IM at the OGJ had a higher prevalence of postprandial acid reflux compared with patients without IM. No differences were observed in LOS pressure (pre- and postprandially) or in the prevalence of TLOSRs. However, in the postprandial phase, the rate of TLOSRs accompanied by acid reflux was increased in patients with IM.

CONCLUSION

Patients with IM at the OGJ have a higher prevalence of postprandial acid reflux. This is not associated with a higher prevalence of TLOSRs or a decreased LOS pressure but with a higher rate of TLOSRs accompanied by reflux.

Treatment of restless legs syndrome with the dopamine agonist alpha-dihydroergocryptine

An open pilot study with the dopamine agonist alpha-dihydroergocryptine (DHEC) was conducted in 16 patients with idiopathic restless legs syndrome (RLS) over a period of 5 weeks. Following a drug-free interval of 1 week, the patients were treated with daily doses of 10 to 40 mg DHEC. As compared to baseline values, treatment led to a statistically significant reduction of subjective RLS symptoms. Overall complaints at night decreased significantly by 63.9 +/- 38.1% as measured by a visual analogue scale. Detailed evaluation of sensory discomfort, motor restlessness, involuntary movements, as well as sleep quality also showed significant improvement. Side effects were mostly mild and affected mainly the gastrointestinal tract. Five patients needed domperidone for treatment of concomitant nausea. One patient stopped the study due to nausea. In conclusion, the results of this open study suggest a role for DHEC in the treatment of RLS.

Synergistic effect of titanium alloy and collagen type I on cell adhesion, proliferation and differentiation of osteoblast-like cells

A number of studies have demonstrated the pivotal role of collagen in modulating cell growth and differentiation. In bone, where the extracellular matrix is composed of approximately 85% type I collagen, cellular interaction with matrix components has been shown to be important in the regulation of the osteoblast phenotype. Preservation or enhancement of normal osteoblast function and appositional bone formation after implant placement represents a strategy that can be useful for the purpose of improving osseointegration. In order to further improve biocompatibility, we combined two known favorable compounds, namely the titanium alloy, Ti6A14V, with type I collagen. We assessed the in vitro behavior of primary osteoblasts grown on both fibrillar collagen-coated and tropocollagen-coated Ti6A14V in comparison with uncoated titanium alloy, using an improved adsorption procedure. As parameters of biocompatibility, a variety of processes, including cell attachment, spreading, cytoskeletal organization, focal contact formation, proliferation and expression of a differentiated phenotype, were investigated. Our results demonstrated for the first time that in comparison to uncoated titanium alloy, collagen-coated alloy enhanced spreading and resulted in a more rapid formation of focal adhesions and their associated stress fibers. Growing on collagen-coated Ti6A14V, osteoblasts had a higher proliferative capacity and the intracellular expression of osteopontin was upregulated compared to uncoated titanium alloy. Type I collagen-coated titanium alloy exhibits favorable effects on the initial adhesion and growth activities of osteoblasts, which is encouraging for its potential use as bone graft material. Moreover, collagen type I may serve as an excellent biocompatible carrier for osteotropic factors such as cell adhesion molecules (e.g. fibronectin) or bone-specific growth factors.

[Chronic anemia and abdominal pain as a sequela of lead poisoning]

HISTORY AND ADMISSION FINDINGS

3 years ago, a 63-year-old man underwent laparotomia due to clinical signs of acute abdominal pain. The anemia was treated with erythrocyte concentrates. Several weeks before the current admission to our outpatient department, the patient was again hospitalized because of acute abdominal pain and anemia. The patient was then transferred to the University clinic for further medical tests.

INVESTIGATIONS

In addition to a normocytic anemia, a secondary porphyria was found. Further medical tests demonstrated lead poisoning.

DIAGNOSIS, TREATMENT AND COURSE

Initially, the cause of the lead poisoning remained unclear because the patient had reported neither an occuppational nor an environmental exposure to lead. Finally, a prescription-prepared ointment was evaluated, which the patient had applied to his feet and lips over the past 3 years.

CONCLUSION

Lead poisoning can be found outside the realm of occupational exposure; therefore, the knowledge of lead poisoning is still important.

Reduction of voltage-operated sodium currents by the anticonvulsant drug sulthiame

The effect of the sulfonamide derivative sulthiame (Ospolot) on voltage-operated sodium channels was investigated in acutely isolated neurons from the guinea pig hippocampus using the whole-cell patch-clamp technique. Sulthiame in a concentration of 10 microg/ml reduced the inactivating sodium currents without affecting potassium currents. The effect was not dependent on voltage. At therapeutic concentration of 1 to 10 microg/ml sodium currents were reduced by 13 to 25% of control. Reductions of this size (induced by the specific sodium channel blocker tetrodotoxin or by 10 microg/ml sulthiame itself) impaired repetitive generation of action potentials and reduced the maximum discharge frequency by 20 to 40%. In summary, the anticonvulsant drug sulthiame exerts blocking effects on sodium channels which can be assumed to be anticonvulsant and to be different from the effects induced by blockade of carbonic anhydrase.

Cholesterol favors phase separation of sphingomyelin

The phase behavior of mixed lipid dispersions representing the inner leaflet of the cell membrane has been characterized by X-ray diffraction. Aqueous dispersions of phosphatidylethanolamine:phosphatidylserine (4:1 mole/mole) have a heterogeneous structure comprising an inverted hexagonal phase H(II) and a lamellar phase. Both phases coexist in the temperature range 20-45 degrees C. The fluid-to-gel mid-transition temperature of the lamellar phase assigned to phosphatidylserine is decreased from 27 to 24 degrees C in the presence of calcium. Addition of sphingomyelin to phosphatidylethanolamine/phosphatidylserine prevents phase separation of the hexagonal H(II) phase of phosphatidylethanolamine but the ternary mixture phase separates into two lamellar phases of periodcity 6.2 and 5.6 nm, respectively. The 6.2-nm periodicity is assigned to the gel phase enriched in sphingomyelin of molecular species comprising predominantly long saturated hydrocarbon chains because it undergoes a gel-to-fluid phase transition above 40 degrees C. The coexisting fluid phase we assign to phosphatidylethanolamine and phosphatidylserine and low melting point molecular species of sphingomyelin which suppresses the tendency of phosphatidylethanolamine to phase-separate into hexagonal H(II) structure. There is evidence for considerable hysteresis in the separation of lamellar fluid and gel phases during cooling. The addition of cholesterol prevents phase separation of the gel phase of high melting point sphingomyelin in mixtures with phosphatidylserine and phosphatidylethanolamine. In the quaternary mixture the lamellar fluid phase, however, is phase separated into two lamellar phases of periodicities of 6.3 and 5.6 nm (20 degrees C), respectively. The lamellar phase of periodicity 5.6 nm is assigned to a phase enriched in aminoglycerophospholipids and the periodicity 6.3 nm to a liquid-ordered phase formed from cholesterol and high melting point molecular species of sphingomyelin characterized previously by ESR. Substituting 7-dehydrocholesterol for cholesterol did not result in evidence for lamellar phase separation in the mixture within the temperature range 20-40 degrees C. The specificity of cholesterol in creation of liquid-ordered lamellar phase is inferred.

Epidemiological, clinical, and histological characteristics of intestinal metaplasia at the oesophagogastric junction compared to short segments of columnar-lined oesophagus

OBJECTIVE

Intestinal metaplasia (IM) close to the oesophagogastric junction (OGJ) has become a focus of research interest against a background of the rising incidence of malignancies in that area. Studies have focused on the presence of IM in short columnar segments (0-3 cm). Recently it has been suggested that IM at the OGJ and IM in short columnar segments may represent different entities. The objective of this current study was to determine the prevalence of IM in these areas and to assess clinical characteristics in order to test the hypothesis that IM at the OGJ and IM in short columnar segments are different entities.

METHODS

Six hundred and fifty-eight patients referred for gastroscopy, in whom a columnar lining of 0-3 cm was found, participated in the study. Endoscopic oesophagitis was graded, distances to endoscopic landmarks were measured, and biopsies (antrum, corpus, 'cardia', and immediately distal to the squamocolumnar junction) were taken. Biopsies were stained with haematoxylin & eosin, Alcian Blue (pH 2.5), modified Giemsa for Helicobacter pylori (Hp), and immunohistochemistry in cases of a negative Giemsa. According to endoscopy, patients were categorized as having a normal OGJ (0-1 cm) or having a short columnar segment (1 -3 cm, tongues >1 cm).

RESULTS

In this study 77.7% of patients had a normal OGJ (IM-positive 15.1%), and 22.3% had a short columnar segment (IM-positive 29.3%). In the first group, IM was correlated with Hp (P = 0.003) and antral IM (P = 0.002), in the second IM was associated with the presence of a hiatal hernia (P < 0.001) and reflux oesophagitis (P = 0.023).

CONCLUSION

These findings suggest that IM at the OGJ is not the same entity as IM in short columnar segments.

Computer analysis of prolonged lower oesophageal sphincter pressure recordings

The aim of the study was to validate a recently developed computer program for the analysis of prolonged recordings of lower oesophageal sphincter pressure. Thirty 1-hour stretches were selected from sets of 24-h pressure signals recorded from the pharynx, oesophagus, lower oesophageal sphincter (LOS) and stomach in 10 ambulant patients with gastrooesophageal reflux disease. Three experienced investigators visually analysed end-expiratory LOS pressures and transient lower oesophageal sphincter relaxations (TLOSRs), using published criteria. A computer program was developed for calculation of an end-expiratory pressure curve and detection of TLOSRs using the same criteria. Although the results showed an maximum deviation from the mean of 11.1% and 14.8% for manually calculated LOS pressures and visually detected TLOSRs, respectively only 62.1% of the detected TLOSRs were detected by all three observers. LOS pressure as measured by the computer closely approximated the mean of the LOS pressures calculated by the three observers. Although the total number of TLOSRs was comparable to that assessed by visual analysis, the computer detected only 46% of the TLOSRs detected by each observer and 56.8% of the TLOSRs detected by all observers. It is concluded that automated calculation of end-expiratory LOS pressure is feasible and yields reliable results, whereas automated detection of TLOSRs could not be satisfactorily accomplished. Our study showed that improvement of computer algorithms for TLOSR detection is desirable. However, the previously described criteria for detection of TLOSRs are insufficiently precise; further refinement of these criteria will be necessary to reduce the large discrepancies between the outcome of detection of TLOSRs by computer and by humans, and to reduce the equally large discrepancies between the results of detection by different human observers.

Successful transplantation and engraftment of peripheral blood stem cells after cryopreservation, positive and negative purging procedures, and a second cryopreservation cycle

Transplantation of peripheral blood stem cells (PBSC), positively and/or negatively selected immediately after harvest, has become a widely applied therapeutic option in hematological or oncological patients. The following case of peripheral blood stem cell transplantation represents the first case of successful transplantation of PBSC, cryopreserved twice and purged after cryopreservation. PBSC were harvested in a 44-year-old female patient with a low-grade non-Hodgkin's lymphoma stage IV after mobilization with chemotherapy and G-CSF. A total number of 15.2 x 10(6) CD34+ cells/kg bodyweight was harvested with a 36.9% contamination of tumor cells coexpressing CD5 and CD20. After subsequent chemotherapy cycles and cyclophosphamide mobilization, only 0.77 x 10(6) CD34+ cells/kg bodyweight, not sufficient for transplantation, were achieved after positive selection. Therefore, 10.8 x 10(6) cryopreserved CD34+ cells/kg bodyweight were thawed and a positive selection was carried out with the BAXTER Isolex 300i machine. Before additional negative selection, the 0.77 x 10(6) positively selected CD34+ cells/kg bodyweight from the second mobilization were added. A total quantity of 4.4 x 10(6) CD34+ cells/kg bodyweight with a purity of 93.1% representing a recovery of 38% was obtained. Cells were again cryopreserved, stored and retransfused after conditioning the patient with TBI and high-dose cyclophosphamide. The patient engrafted with a WBC count > 1000/microliter on day eight and a platelet count > 20,000/microliter without transfusion support on day 12 post-transplantation. This case indicates that purging procedures can successfully be carried out with cryopreserved cell material and that purified CD34+ cells can be cryopreserved a second time before transplantation, without affecting their hematopoietic capacity.

Filtration of methylene blue-photooxidized plasma: influence on coagulation and cellular contamination

BACKGROUND

Virus inactivation of plasma can be achieved by photodynamic methods in the presence of phenothiazine dyes such as methylene blue (MB). Subsequent filtration may increase the efficacy of virus inactivation and reduce adverse effects of WBC contamination and MB.

STUDY DESIGN AND METHODS

This study examined the effect of filtration with three different filters (MBF1, MBF2, and MBF3) on MB concentration, residual cells, coagulation factors, and activation measures of coagulation, fibrinolysis, and complement in MB-treated (1 microM/L) plasma units.

RESULTS

Filtration reduced the concentration of MB by > or = 89 percent. WBCs were depleted by 92 percent (MBF1) and >99.9 percent (MBF2 and MBF3). Treatment with MB significantly decreased the coagulation potency from levels in untreated plasma, as measured by thromboplastin time ratio (112 +/- 18% vs. 95 +/- 11%), activated partial thromboplastin time (40 +/- 3 sec vs. 44 +/- 3 sec), thrombin time (16.9 +/- 1.1 sec vs. 18.6 +/- 1.5 sec), factor VIII (1.09 +/- 0.21 U/mL vs. 0.85 +/- 0.13 U/mL), and vWF (0.94 +/- 0.65 U/mL vs. 0.65 +/- 0.24 U/mL). Filtration did not further decrease these values, while factor XI (0.75 +/- 0.22 U/mL vs. 0.37 +/- 0.20 U/mL) and prekallikrein values decreased in MB plasma units filtered with the MBF3. In addition, activated factor XII (0.7 +/- 0.5 microg/L vs. 4.5 +/- 1.0 microg/L) increased.

CONCLUSION

WBCs and MB can be eliminated from MB-treated plasma units by filtration. Differences in biocompatibility of the different filters, especially the influence on the contact phase of coagulation, must be taken into consideration.

Quantification of the metal distribution in metallothioneins of the human liver by HPLC coupled with ICP-AES

Fractions containing metallothioneins (MT's), extracted from the liver cytosol of humans, were analysed to determine the complete distribution pattern of the metals copper, cadmium and zinc. Samples of cirrhotic livers which had come from organs removed during transplantation were examined for differences in the trace-element binding pattern. After the extraction of supernatants from the tissue samples, membrane ultrafiltration of the cytosolic solution was carried out to separate all high-molecular proteins with molecular weights >100 kDa. This procedure retains the metal content of the MT's in its initial form, in contrast to the often-used heat treatment of samples, which changes the copper distribution significantly. The MT's themself were isolated using size exclusion and anion exchange chromatography. Their metal content was determined simultaneously on-line by combination with an ICP-AES as element detector. Calibration of the procedure was performed by means of a column by-pass-injection of elemental standards into the separation system. The MT content in the samples was calculated using the determined metal concentrations and the generally accepted metal/protein ratios for Cu (12:1), Cd (7:1) and Zn (7:1). These values were compared with values resulting from a 109Cd-saturation-assay. When various liver samples of different pathogenesis were compared, the highest level of Cu-MT was found in primary biliary cirrhosis.