Four possible cases of osteomalacia: The value of a multidisciplinary diagnostic approach.

Rickets and residual rickets are often encountered in Dutch archeological skeletal samples. However, no archeological Dutch paleopathological case of adult osteomalacia has been described in literature to date. This paper describes the first four archeological Dutch paleopathological cases of osteomalacia and assesses the value of the various modalities (macroscopic assessment, radiology and histology) that may be used for diagnosis. The skeletal remains investigated originate from the Meerenberg psychiatric hospital cemetery in Bloemendaal, the Netherlands, and date from 1891 - 1936. The remains of 69 adult individuals were inspected for macroscopic lesions which may be associated with osteomalacia. In cases suspect for osteomalacia, complimentary radiological and histological investigations (BSE-SEM and light microscopy) were performed. Macroscopically, four individuals presented with lesions (highly) suggestive of osteomalacia. Histological examination (both BSE-SEM and light microscopy) provided valuable information to come to an eventual diagnosis of osteomalacia in all four cases. Light microscopy proved to be an feasible alternative for BSE-SEM. The added value of radiological analyses was limited. The individuals identified were most likely patients in the psychiatric hospital, and the reason for their institutionalization and/or the regime in the institution may have played a role in the development of the osteomalacia observed.

Increased epidermal thickness and abnormal epidermal differentiation in keloid scars.

BACKGROUND: The pathogenesis underlying keloid formation is still poorly understood. Research has focused mostly on dermal abnormalities, while the epidermis has not yet been studied. OBJECTIVES: To identify differences within the epidermis of mature keloid scars compared with normal skin and mature normotrophic and hypertrophic scars. METHODS: Rete ridge formation and epidermal thickness were evaluated in tissue sections. Epidermal proliferation was assessed using immunohistochemistry (Ki67, keratins 6, 16 and 17) and with an in vitro proliferation assay. Epidermal differentiation was evaluated using immunohistochemistry (keratin 10, involucrin, loricrin, filaggrin, SPRR2, SKALP), reverse-transcriptase polymerase chain reaction (involucrin) and transmission electron microscopy (stratum corneum). RESULTS: All scars showed flattening of the epidermis. A trend of increasing epidermal thickness correlating to increasing scar abnormality was observed when comparing normal skin, normotrophic scars, hypertrophic scars and keloids. No difference in epidermal proliferation was observed. Only the early differentiation marker involucrin showed abnormal expression in scars. Involucrin was restricted to the granular layer in healthy skin, but showed panepidermal expression in keloids. Normotrophic scars expressed involucrin in the granular and upper spinous layers, while hypertrophic scars resembled normotrophic scars or keloids. Abnormal differentiation was associated with ultrastructural disorganization of the stratum corneum in keloids compared with normal skin. CONCLUSIONS: Keloids showed increased epidermal thickness compared with normal skin and normotrophic and hypertrophic scars. This was not due to hyperproliferation, but possibly caused by abnormal early terminal differentiation, which affects stratum corneum formation. Our findings indicate that the epidermis is associated with keloid pathogenesis and identify involucrin as a potential diagnostic marker for abnormal scarring.

Betulinic acid induces a novel cell death pathway that depends on cardiolipin modification.

Cancer is associated with strong changes in lipid metabolism. For instance, normal cells take up fatty acids (FAs) from the circulation, while tumour cells generate their own and become dependent on de novo FA synthesis, which could provide a vulnerability to target tumour cells. Betulinic acid (BetA) is a natural compound that selectively kills tumour cells through an ill-defined mechanism that is independent of BAX and BAK, but depends on mitochondrial permeability transition-pore opening. Here we unravel this pathway and show that BetA inhibits the activity of steroyl-CoA-desaturase (SCD-1). This enzyme is overexpressed in tumour cells and critically important for cells that utilize de novo FA synthesis as it converts newly synthesized saturated FAs to unsaturated FAs. Intriguingly, we find that inhibition of SCD-1 by BetA or, alternatively, with a specific SCD-1 inhibitor directly and rapidly impacts on the saturation level of cardiolipin (CL), a mitochondrial lipid that has important structural and metabolic functions and at the same time regulates mitochondria-dependent cell death. As a result of the enhanced CL saturation mitochondria of cancer cells, but not normal cells that do not depend on de novo FA synthesis, undergo ultrastructural changes, release cytochrome c and quickly induce cell death. Importantly, addition of unsaturated FAs circumvented the need for SCD-1 activity and thereby prevented BetA-induced CL saturation and subsequent cytotoxicity, supporting the importance of this novel pathway in the cytotoxicity induced by BetA.

Characterization of bovine neutrophil gelatinase-associated lipocalin.

A protein of relative molecular mass of approximately 25,000 was purified from bovine colostrum by cation-exchange and size-exclusion chromatography. The N-terminus of the protein matched the sequence predicted by the National Center for Biotechnology Information for the bovine homolog of human neutrophil gelatinase-associated lipocalin, a glycoprotein of relative molecular mass 25,000 belonging to the family of lipocalins. The protein was further designated as bovine neutrophil gelatinase-associated lipocalin (bNGAL). Sodium dodecyl sulfate-PAGE of enzymically deglycosylated bNGAL indicated that the intact protein bears one N-linked glycan. Monosaccharide and mass spectrometric analyses of released N-linked carbohydrates revealed the presences of complex- and hybrid-type glycans, with galactose substituted with N-acetylgalactosamine. This substitution is typical for glycoproteins expressed in the bovine mammary gland. A specific ELISA revealed bNGAL concentrations in plasma and mature milk of about 0.05 and 1 microg/mL, respectively, whereas values as high as 51 microg/mL were measured in colostrum. Thus, we have isolated and characterized a novel bovine (milk) protein that is a new member of the lipocalin family.

Sub-chronic (13-week) oral toxicity study in rats with recombinant human lactoferrin produced in the milk of transgenic cows.

The oral toxicity of recombinant human lactoferrin (rhLF) produced in the milk of transgenic cows was investigated in Wistar rats by daily administration via oral gavage for 13 consecutive weeks, 7 days per week. The study used four groups of 20 rats/sex/dose. The control group received physiological saline and the three test groups received daily doses of 200, 600 and 2000 mg of rhLF per kg body weight. Clinical observations, growth, food consumption, food conversion efficiency, water consumption, neurobehavioural testing, ophthalmoscopy, haematology, clinical chemistry, renal concentration test, urinalysis, organ weights and gross examination at necropsy and microscopic examination of various organs and tissues were used as criteria for detecting the effects of treatment. Overall, no treatment-related, toxicologically significant changes were observed. The few findings that may be related to the treatment (lower cholesterol in high-dose females, lower urinary pH in high-dose males and females and very slightly higher kidney weight in high-dose females) were considered of no toxicological significance. Based on the absence of treatment-related, toxicologically relevant changes, the no-observed-adverse-effect level (NOAEL) was considered to be at least 2000 mg/kg body weight/day.

Histatin 5 and derivatives. Their localization and effects on the ultra-structural level.

Histatins, a family of cationic peptides present in saliva, are active against the opportunistic yeast Candida albicans. The mechanism of action is still unclear. Histatin 5 and more potent synthetic variants, dhvar4 and dhvar5, were used to study localization and effects on morphology on the ultra-structural level. Although all peptides induced leakage, no association with the plasma membrane, indicative for permanent pores, was observed with immuno-gold-labeling. Freeze-fracturing showed severe changes of the plasma membrane. Together with, for the dhvars, the loss of intracellular integrity, this suggests that leakage may be a secondary effect rather than an effect of formation of permanent pores.

Coating of coverslips with glow-discharged carbon promotes cell attachment and spreading probably due to carboxylic groups.

BACKGROUND: For high-resolution microscopy, cells have to be analyzed through thin glass coverslips. Therefore, it is necessary to culture cells on coverslips for preservation of cell morphology. We found cell attachment and spreading to be relatively slow processes, even when cells were plated on coated coverslips. This slowness presents a problem, particularly when synchronized cell populations are used. METHODS: In this paper, we present a method that is based on glow-discharged carbon coating of coverslips which promotes rapid attachment and spreading of cells, enabling rapid analysis of cells after plating. Results obtained with carbon-coated coverslips were compared with those of other types of coating. Two fibroblast lines, an epithelial cell line, and a carcinoma cell line were tested. RESULTS AND CONCLUSIONS: All cell lines showed a rapid adhesion on carbon-coated coverslips. With fibroblasts we found the carbon coating to be superior to other coatings tested, mainly because the carbon did not influence cell morphology. Using synchronized or irradiated cells produced similar results. The superior performance of carbon coating is probably due to carboxylic groups on the glow-discharged carbon layer. The carbon layer does not interfere with microscopy or immunocytochemical staining procedures.

Velocity constancy in a virtual reality environment.

During everyday life the brain is continuously integrating multiple perceptual cues in order to allow us to make decisions and to guide our actions. In this study we have used a simulated (virtual reality--VR) visual environment to investigate how cues to speed judgments are integrated. There are two sources that could be used to provide signals for velocity constancy: temporal-frequency or distance cues. However, evidence from most psychophysical studies favours temporal-frequency cues. Here we report that two depth cues that provide a relative object--object distance--disparity and motion parallax--can provide a significant input to velocity-constancy judgments, particularly when combined. This result indicates that the second mechanism can also play a significant role in generating velocity constancy. Furthermore, we show that cognitive factors, such as familiar size, can influence the perception of object speed. The results suggest that both low-level cues to spatiotemporal structure and depth, and high-level cues, such as object familiarity, are integrated by the brain during velocity estimation in real-world viewing.

Role of the first N-terminal basic cluster of human lactoferrin (R2R3R4R5) in the interactions with the Jurkat human lymphoblastic T-cells.

We previously characterized a receptor of Mr 105,000 for human lactoferrin (hLf) on Jurkat human lymphoblastic T-cells. To delineate the role of R2R3R4R5 of hLf in the interaction with cells, we studied the binding of hLf variants obtained either by tryptic proteolysis (hLf-2N, hLF-3N and hLf-4N) or by mutagenesis (rhLf-5N). Consecutive removal of N-terminal arginine residues from hLf progressively increased the binding affinity but decreased the number of binding sites on the cells. The binding parameters of bovine Lf and native hLf did not differ, whereas the binding parameters of murine Lf resembled those of rhLf-5N. Culture of Jurkat cells in the presence of chlorate, which inhibits sulfation, reduced the number of binding sites for both native hLf and hLf-3N but not for rhLf-5N indicating that the hLf binding sites include sulfated molecules. The results suggest that the interaction of hLf with about 80,000 binding sites per Jurkat cell, mainly sulfated molecules, is dependent on R2R3R4, but not on R5. Interaction with about 20,000 binding sites per cell, presumably the hLf receptor, does not require the first N-terminal basic cluster of hLf. We conclude that the deletion of R2-R5 from hLf may serve to modulate the nature of its binding to cells and thereby its effects on cellular physiology.

Characterization of recombinant human lactoferrin secreted in milk of transgenic mice.

Human lactoferrin (hLF) is an iron-binding protein involved in host defense against infection and severe inflammation. Transgenic mice were produced harboring either hLF cDNA or genomic hLF sequences fused to regulatory elements of the bovine alphaS1 casein gene. Recombinant hLF expressed in the milk of transgenic mice (transgenic hLF) was compared with natural (human milk-derived) hLF. Immunological identity of the two forms was shown by double antibody immunoassays and the absence of an anti-hLF antibody response in transgenic mice on hyperimmunization with natural hLF. Mono S cation-exchange chromatography and N-terminal protein sequencing of transgenic and natural hLF revealed identical cationicity and N-terminal sequences. SDS-polyacrylamide gel electrophoresis and absorbance measurements of purified transgenic hLF showed this protein was 90% saturated with iron, whereas natural hLF is only 3% saturated. The pH-mediated release of iron from transgenic hLF was not different from that of iron-saturated natural hLF. Unsaturated transgenic hLF could be completely resaturated upon addition of iron. Slight differences in mobility between transgenic and natural hLF on SDS-polyacrylamide gel electrophoresis were abolished by enzymatic deglycosylation. Binding of transgenic and natural hLF to a range of ligands, including bacterial lipopolysaccharide, heparin, single-stranded DNA, Cibacron blue FG 3A, and lectins, was not different. Based on these observations, we anticipate that (unsaturated) rhLF and natural hLF will exert similar, if not identical, antibacterial and anti-inflammatory activity in vivo.

N-terminal stretch Arg2, Arg3, Arg4 and Arg5 of human lactoferrin is essential for binding to heparin, bacterial lipopolysaccharide, human lysozyme and DNA.

Human lactoferrin (hLF), a protein involved in host defence against infection and excessive inflammation, interacts with heparin, the lipid A moiety of bacterial lipopolysaccharide, human lysozyme (hLZ) and DNA. To determine which region of the molecule is important in these interactions, solid-phase ligand binding assays were performed with hLF from human milk (natural hLF) and N-terminally deleted hLF variants. Iron-saturated and natural hLF bound equally well to heparin, lipid A, hLZ and DNA. Natural hLF lacking the first two N-terminal amino acids (Gly1-Arg2) showed reactivities of one-half, two-thirds, one-third and one-third towards heparin, lipid A, hLZ and DNA respectively compared with N-terminally intact hLF. A lack of the first three residues (Gly1-Arg2-Arg3) decreased binding to the same ligands to one-eighth, one-quarter, one-twentieth and one-seventeenth respectively. No binding occurred with a mutant lacking the first five residues (Gly1-Arg2-Arg3-Arg4-Arg5). An anti-hLF monoclonal antibody (E11) that reacts to an N-lobe epitope including Arg5 completely blocked hLF-ligand interaction. These results show that the N-terminal stretch of four consecutive arginine residues, Arg2-Arg3-Arg4-Arg5, has a decisive role in the interaction of hLF with heparin, lipid A, hLZ and DNA. The role of limited N-terminal proteolysis of hLF in its anti-infective and anti-inflammatory properties is discussed.

The N-terminal Arg2, Arg3 and Arg4 of human lactoferrin interact with sulphated molecules but not with the receptor present on Jurkat human lymphoblastic T-cells.

We previously characterized a 105 kDa receptor for human lactoferrin (hLf) on Jurkat human lymphoblastic T-cells. To delineate the role of the basic cluster Arg2-Arg3-Arg4-Arg5 of hLf in the interaction with Jurkat cells, we isolated N-terminally deleted hLf species of molecular mass 80 kDa lacking two, three or four N-terminal residues (hLf-2N, hLf-3N and hLf-4N) from native hLf that had been treated with trypsin. Native hLf bound to 102000 sites on Jurkat cells with a dissociation constant (Kd) of 70 nM. Consecutive removal of N-terminal arginine residues from hLf progressively increased the binding affinity but decreased the number of binding sites on the cells. A recombinant hLF mutant lacking the first five N-terminal residues (rhLf-5N) bound to 17000 sites with a Kd of 12 nM. The binding parameters of bovine lactoferrin (Lf) and native hLf did not significantly differ, whereas the binding parameters of murine Lf (8000 sites; Kd 30 nM) resembled those of rhLf-5N. Culture of Jurkat cells in the presence of chlorate, which inhibits sulphation, decreased the number of binding sites for both native hLf and hLf-3N but not for rhLf-5N, indicating that the hLf-binding sites include sulphated molecules. We propose that the interaction of hLf with a large number of binding sites (approx. 80000 per cell) on Jurkat cells is dependent on Arg2-Arg3-Arg4, but not on Arg5. Interaction with approx. 20000 binding sites per cell, presumably the hLf receptor, does not require the first N-terminal basic cluster of hLf. Moreover, the affinity of hLf for the latter binding site is enhanced approx. 6-fold after removal of the first basic cluster. Thus N-terminal proteolysis of hLf in vivo might serve to modulate the nature of its binding to cells and thereby its effects on cellular physiology.

Heterogeneity in utilization of N-glycosylation sites Asn624 and Asn138 in human lactoferrin: a study with glycosylation-site mutants.

Human lactoferrin (hLF) is a glycoprotein involved in the host defence against infection and excessive inflammation. Our objective was to determine to what extent each of the three sequons for N-linked glycosylation in hLF is actually used. Human kidney-derived 293(S) cell lines expressing recombinant hLF (rhLF) or glycosylation-site mutants were produced. The mutations involved replacement of asparagine residues with glutamine at one or more sequons for N-glycosylation (Asn138, Asn479 and Asn624). Comparative SDS/PAGE analyses of rhLF, mutated rhLF and human-milk-derived (natural) hLF led us to propose that glycosylation of hLF occurs at two sites (at Asn138 and Asn479) in approx. 85% of all hLF molecules. Glycosylation at a single site (Asn479) or at all three sites occurs in approx, 5% and 9% of hLF respectively. The extent of glycosylation at Asn624 was increased to approx. 29% and 40% of Asn479 and Asn138/479 mutant molecules respectively, which indicates that glycosylation at Asn624 in natural hLF might be limited by glycosylation at Asn479. The presence in supernatant of unglycosylated hLF (approx. 60% of the total) after mutations of Asn138 and Asn479 suggests that glycosylation of hLF is not an absolute requirement for its secretion. The pronounced degradation of unglycosylated hLF in supernatant after mutation at all three glycosylation sites (Asn138/479/624 mutant) but not after mutation at both Asn138 and Asn479 suggests that an altered conformation rather than the lack of glycosylation has rendered the Asn138/479/624 mutant susceptible to intra- and/or extra-cellular degradation.

Metamerisms in Structure-from-motion perception.

As a three-dimensional object is moving through our world, we generally obtain a vivid impression of both its structure and its motion through space. The time-course of two-dimensional projections of the scene (optic flow) is important in conveying this three-dimensional information to us. The extent to which we can solve this specific inverse problem, i.e. infer a three-dimensional scene from two-dimensional flow, depends on the accuracy with which the required flow characteristics are processed by our visual system. In adequate two-dimensional processing can lead to incomplete representations of the three-dimensional world (three-dimensional metric information is lost). Then the motion and structure of objects can no longer be recovered uniquely. Consequently, metameric classes of three-dimensional representations arise (e.g. only affine properties are conserved). this study investigates under what conditions we find metameric combinations of the perceived attitude and perceived rotation of a plane. Our subjects are presented with stimuli consisting of two horizontally separated planar patches rotating back and forth in depth about vertical axes. Subjects are required to match both the attitude and the rotation magnitude of these two patches. We vary the attitude from 15 to 60 deg vertical slant, and the rotation magnitude from 28 to 98 deg. We find that the matched slant and rotation settings vary widely. For high slant values and for small rotations, attitude and rotation settings become highly correlated, suggesting metamery. For low slant values and for large rotations, the correlation almost disappears, suggesting that both quantities are estimated independently and uniquely. Our paradigm reveals that with one task and one type of stimulus a gradual transition occurs from unique settings (metric representations) to metameric classes of settings (e.g. affine representations).

Discriminating the volume of motion-defined solids.

We investigated the ability of human observers to discriminate an important global 3-D structural property, namely volume, of motion-defined objects. We used convex transparent wire-frame objects consisting of about 12 planar triangular facets. Two objects, vertically separated by 7 degrees, were shown simultaneously on a computer display. Both revolved at 67 degrees/sec around a common vertical axis through their centers of mass. Observers watched the objects monocularly for an average of three full rotations before they responded. We measured volume discrimination as a function of absolute volume (3-48 cm3; 1 m viewing distance) and shape (cubes, rods, and slabs of different regularity). We found that (1) volume discrimination performance can be described by Weber's law, (2) Weber fractions depend strongly on the particular combination of shapes used (regular shapes, especially cubes, are easiest to compare, and similar shapes are easier to compare than different shapes), and (3) humans use a representation of volume that is more veridical and stable in the sense of repeatability than a strategy based on the average visible (2-D) area would yield.

Contractile responses to various stimuli in isolated resistance vessels from simultaneously hypertensive and streptozotocin-diabetic rats.

Diabetes mellitus and hypertension are common chronic diseases that frequently occur simultaneously. The induction of streptozotocin (STZ) diabetes mellitus in spontaneously hypertensive rats (SHR) offers the opportunity to investigate the influence of both entities in a reproducible manner. We investigated the effects of various vasoconstrictors on isolated small arteries from the mesenteric vascular bed of normotensive rats (Wistar-Kyoto rats, WKY) and SHR with chronic (8 weeks), STZ-induced diabetes mellitus. No consistent changes in hemodynamic parameters of the (STZ-) normotensive and (STZ-) hypertensive rats were noted. The K(+)-normalization procedure yields the individual optimal lumen diameter, which was the same for the arteries of the four groups of rats. The passive wall tension resulting from this normalization procedure was higher only in preparations from the control hypertensive group as compared with those from the control normotensive rats. Morphological investigations showed that small arteries from control SHR had an increased tunica media thickness as compared with those of control WKY; the STZ-WKY had an increased tunica media thickness as compared with preparations from control WKY. The vasoconstriction caused by alpha 1-adrenoceptor stimulation [norepinephrine (NE), methoxamine] and serotonin is unchanged in chronic experimental diabetes. The diabetic state reduced the sensitivity [-log EC50(M)] for the concentration-response curves (CRC) of calcium chloride. The CRC of potassium chloride indicated the same sensitivities, but maximal active wall tensions of vessels from STZ-SHR were reduced as compared with those from STZ-WKY. The well-known enhancement of the effects of various contractile stimuli caused by hypertension could not be demonstrated for the isolated small arteries used in the present study, although a nonsignificant tendency was observed. However, the STZ-diabetic state did not cause important additional pharmacodynamic changes, despite the morphological alterations in those vessels.

Glycosylated and unglycosylated human lactoferrins both bind iron and show identical affinities towards human lysozyme and bacterial lipopolysaccharide, but differ in their susceptibilities towards tryptic proteolysis.

We studied the role of N-glycosylation of human lactoferrin (hLF) with respect to properties that are relevant to its antibacterial and anti-inflammatory activities. A human kidney-derived 293(S) cell line that constitutively expresses recombinant hLF (rhLF) was produced. The reactivity towards various antibodies of rhLF that had been expressed in the absence or presence of tunicamycin (which blocks N-linked glycosylation) did not differ from that of natural (human milk-derived) hLF. Cation-exchange chromatography and N-terminal protein sequencing showed identical cationic properties and an intact N-terminal sequence for rhLF and natural hLF. SDS/PAGE of rhLF expressed in the presence of tunicamycin revealed a protein with the same M(r) as that of enzymically deglycosylated natural hLF. Both glycosylated and unglycosylated rhLF appeared to be completely saturated with iron. The affinity of natural hLF, glycosylated and non-glycosylated rhLF for both human lysozyme (Kd 4.5 x 10(-8) M) and bacterial lipopolysaccharide did not differ. SDS/PAGE of hLF species subjected to trypsin indicated that unglycosylated rhLF was much more susceptible to degradation. Furthermore, this analysis suggests that N-glycosylation heterogeneity in natural hLF and rhLF resides in the C-lobe. Thus our results provide no argument for differential antibacterial and/or anti-inflammatory activity of natural and (glycosylated) rhLF and suggest that a major function of glycosylation in hLF is to protect it against proteolysis.

Extraction of relief from visual motion.

We quantified the ability of human subjects to discriminate the relative distance of two points from a slanted plane when viewing the projected velocities of this scene (orthographic projection). The relative distance from a plane (called relief) is a 3-D property that is invariant under linear (affine) transformations. As such, relief can in principle be extracted from the instantaneous projected velocity field; a metric representation, which requires the extraction of visual acceleration, is not required. The stimulus consisted of a slanted plane P (specified by three points) and two points Q1 and Q2 that are non-coplanar with P. This configuration of points oscillated rigidly around the vertical axis. We have measured the systematic error and accuracy with which human subjects estimate the relative distance of points Q1 and Q2 from plane P as a function of the slant of P. The systematic error varies with slant: it is low for small slant values, reaches a maximum for medium slant values, and drops again for high slant values. The accuracy covaries with the systematic error and is thus high for small and large slant values and low for medium slant values. These results are successfully modeled by a simple relief-from-motion computation based on local estimates of projected velocities. The data are well predicted by assuming (1) a measurement error in velocity estimation that varies proportionally to velocity (Weber's law) and (2) an eccentricity-dependent underestimation of velocity.

Glycosylphosphatidylinositol (GPI)-anchored membrane proteins are constitutively down-regulated in psoriatic skin.

Hyperproliferation of keratinocytes (KCs) in psoriasis has been found to be associated with excessive activation of a phospholipase C (PLC)/protein kinase C (PKC) signal transduction system. The molecular species of PLCs which are activated in psoriasis have not been thoroughly investigated. It was envisaged that if glycosylphosphatidylinositol (GPI)-specific PLC was activated in the membrane of psoriatic epidermal cells, it would render these cells devoid of those proteins which are anchored to the cell membrane through their GPI moiety. In order to test this possibility, four GPI proteins (CD16, CD55, CD58, and CD59) were determined immunohistochemically in normal and psoriatic skin. In normal skin, CD55 and CD59 were strongly expressed on epithelium and vascular structures, whereas CD16 and CD58 were strongly expressed only on epithelium. The expression of all four GPI proteins was decreased in non-lesional psoriatic skin and virtually abolished in lesional psoriatic skin. A control transmembrane protein, CD46, was strongly expressed in normal and non-lesional psoriatic skin, and its expression was not significantly decreased in psoriatic lesions. The absence or reduction of GPI proteins was not seen in the lesions of several other inflammatory and proliferative diseases studied.

The influence of nifedipine and mioflazine on mitochondrial calcium overload in normoxic and ischaemic guinea-pig hearts.

The influence of nifedipine (20 nM) and mioflazine (300 nM), i.e. concentrations inducing a 60-70% recovery of cardiac function during reperfusion of globally ischaemic guinea-pig working hearts, on the mitochondrial calcium content was investigated in normoxic, globally ischaemic and reperfused globally ischaemic guinea-pig working hearts. Mitochondrial calcium was determined electronmicroscopically with oxalate-pyroantimonate method. In normoxic hearts both nifedipine and mioflazine reduced the mitochondrial calcium content. Global ischaemia for 45 min and subsequent reperfusion for 25 min resulted in a pronounced mitochondrial calcium overload and damage to the cellular structure. In ischaemic and in reperfusion hearts the drugs maintained mitochondrial calcium at pre-ischaemic levels and decreased the damage to the cellular structure.