[Endoventricular patch plasty in patients with idiopathic dilated cardiomyopathy: an alternative to heart transplantation?]

BACKGROUND

Although the concept of reducing wall tension as a treatment for advanced heart failure is convincing, clinical data from the Batista operation are conflicting. Despite a number of publications, it is not clear whether left ventricular reduction surgery is truly of benefit for patients with idiopathic, dilated cardiomyopathy (DCM). Surgery may reduce wall tension but the reason for dilation and contractile dysfunction remains. Thus, the potential benefit of the operation may be overshadowed by the natural course of the underlying disease.

CASES

We report a series of five cases where left ventricular reduction was performed and physiological geometry was restored in patients with DCM by a modification of Dor's endoventricular patch plasty. All patients demonstrated an improvement in cardiac function immediately after the operation. This improvement was sustained in one of the patients at 18 months follow-up. Another patient developed severe heart failure due to therapy resistant ventricular arrhythmia (Lown IVb), and underwent successful transplantation 4 months after ventricular reduction surgery. Left ventricular dilation reoccurred in two patients 9 and 12 months after reduction surgery, and they were listed for transplant. One patient died after 9 weeks due to sepsis and respiratory dysfunction.

CONCLUSIONS

Although the endoventricular patch plasty as used in this study is well tolerated by most patients with dilated cardiomyopathy and results in immediate improvement of contractile function, the long-term benefits of this technique for DCM are uncertain. Thus, the technique is currently not an alternative for heart transplantation. However, the procedure may be an option in patients with contraindications for transplantation.

Perceptual phenomena after unilateral arm amputation: a pre-post-surgical comparison

Painful and non-painful phantom phenomena occur frequently after amputations but are rarely investigated in the perioperative stage. The goal of the present study was the assessment of phantom phenomena, pain and changes in primary somatosensory cortex prior to and after upper limb amputation. Two patients who suffered from metastatic carcinoma were examined 2 days prior to and 7 days after the amputation of an arm using comprehensive psychometric assessments and neuroelectric source imaging. Both patients reported phantom limb pain that was similar to their pre-amputation pain. In one patient, reorganization of the mouth area into the deafferented hand area took place immediately after the amputation. In the other patient reorganization had occurred prior to the amputation possibly related to non-use of the arm several years prior to the amputation.

Left ventricular reduction for idiopathic dilated cardiomyopathy as alternative to transplant--truth or dare?

BACKGROUND

Although the concept of reducing wall tension a treatment for advanced heart failure is convincing, clinical data from the Batista operation are conflicting. Despite a number of publications, it is not clear whether left ventricular reduction surgery truly benefits patients with idiopathic, dilated cardiomyopathy (DCM). Surgery may reduce wall tension, but the reason for dilation and contractile dysfunction remains. Thus, the potential benefit of the operation may be overshadowed by the natural course of the underlying disease.

CASES

We report a series of five cases where left ventricular reduction was performed and physiological geometry was restored in patients with DCM by a modification of Dor's endoventricular patch plasty. All patients demonstrated an improvement in cardiac function immediately after the operation. This improvement was sustained in one of the patients after 18 months of follow-up. Another patient developed severe heart failure due to therapy-resistant ventricular arrhythmia (Lown IV b), and underwent successful transplantation 4 months after ventricular reduction surgery. Left ventricular dilation reoccurred in two patients 9 and 12 months after reduction surgery, and they were listed for transplant. One patient died after 9 weeks due to sepsis and respiratory dysfunction.

CONCLUSIONS

Although the endoventricular patch plasty, as used in this study, is well tolerated by most patients with dilated cardiomyopathy, and results in immediate improvement of contractile function, the long-term benefits of this technique for DCM are uncertain. Thus, the technique is currently not an alternative for heart transplantation. However, the procedure may be an option in patients with contraindications for transplantation.

Millipedes and earthworms increase the decomposition rate of 15N-labelled winter rape litter in an arable field

Effects of millipedes and earthworms on the decomposition of 15N-labelled litter of winter oilseed rape were investigated in a microcosm field experiment over a period of 264 days on an oat field near Göttingen managed by integrated farming. A total of 32 microcosms were filled with defaunated soil. 15N-labelled rape litter was placed either on top of the soil or buried into the soil simulating mulching and ploughing, respectively. To the microcosms nine adult individuals of Blaniulus guttulatus (Diplopoda) and two of Aporrectodea caliginosa (Lumbricidae) were added separately or in combination. In general, the presence of the animals accelerated the decomposition rate of the litter material. The effects were most pronounced in the presence of Aporrectodea caliginosa. The total amount of nitrate, ammonium and the amount of 35N leached from the microcosms was increased in the presence of earthworms or of both earthworms and millipedes. Both species proved to be important members of the detritus food web of the agricultural system studied.

Hepatic iron overload in aceruloplasminaemia

We report the case of a 52 year old male with diabetes mellitus and long standing evidence of hepatic iron excess. Initially considered to have haemochromatosis, this patient was reevaluated when hepatic iron stores were found to be unaffected by a prolonged course of weekly phlebotomy. The development of neurological disease prompted diagnostic consideration of aceruloplasminaemia, which we confirmed by demonstration of a novel frameshift mutation in the ceruloplasmin gene. Our inability to resolve the patient's iron overload by regular phlebotomy is consistent with recent animal studies indicating an essential role for ceruloplasmin in cellular iron efflux. Evaluation of this case underscores the clinical relevance of aceruloplasminaemia in the differential diagnosis of hepatic iron overload and provides insight into the pathogenetic mechanisms of hepatocellular iron storage and efflux.

Cloning, expression and subcellular localization of two novel splice variants of mouse transient receptor potential channel 2

Transient receptor potential channels (TRPCs) are known as candidate molecular correlates of receptor-activated or store-operated calcium entry. While functional roles for most TRPCs have been suggested, the physiological relevance of TRPC2 remains obscure. Whereas human and bovine TRPC2 are candidate pseudogenes, full-length rodent TRPC2 transcripts have been reported. There is, however, considerable controversy concerning mRNA splicing, tissue distribution and the function of these proteins. We report the molecular cloning of two novel murine TRPC2 splice variants, mTRPC2alpha and mTRPC2beta. mTRPC2alpha RNA is expressed at low levels in many tissues and cell systems, while mTRPC2beta is exclusively and abundantly expressed in the vomeronasal organ (VNO). When expressed in human embryonic kidney (HEK)-293 cells, mTRPC2 did not enhance receptor- or store-activated calcium entry. In order to investigate the basis of such a functional defect, mTRPC2-green fluorescent protein fusion proteins were examined by confocal microscopy. Fusion proteins were retained in endomembranes when expressed in HEK-293 or other cells of epithelial or neuronal origin. Co-expression of TRPC2 with other TRPCs did not restore plasma-membrane trafficking. We conclude that TRPC2 may form functional channels in the cellular context of the VNO, but is unlikely to have a physiological function in other tissues.

Steroidal sigma receptor ligands affect signaling pathways in human spermatozoa

In human spermatozoa, Ca(2+) entry is stimulated by progesterone or prostaglandin E(1) (PGE(1)). The regulation of cation currents by progestins involves sigma receptors, and sigma binding sites are abundant in testis. We examined the effects of sigma ligands on human spermatozoa. Ca(2+) entry induced by progesterone or PGE(1) was not altered by the sigma ligands haloperidol and ditolylguanidine. However, the steroidal sigma ligands RU 3117 and RU 1968 had distinct effects. Stimulation by RU 3117 resulted in activation and homologous desensitization of the sperm progesterone receptor but not of the PGE(1) receptor. Because haloperidol and ditolylguanidine did not affect RU 3117 and progesterone actions in spermatozoa, we conclude that sigma receptors are not involved. However, RU 1968 potently inhibited both the progesterone- and PGE(1)-induced Ca(2+) entry and acrosome reaction. At higher concentrations, RU 1968 also inhibited hormonal Ca(2+) signaling in fibroblasts. Despite suppression of Ca(2+) mobilization, inhibition of phospholipase C by RU 1968 was not observed. Furthermore, RU 1968 did not impair the binding of inositol-1,4,5-trisphosphate to its endoplasmic reticulum receptor. Because RU 1968 preferentially inhibits signaling pathways in spermatozoa, the future development of more selective drugs structurally related to RU 1968 may be a novel approach for pharmacological contraception.

[Doppler ultrasound examination of fetal umbilical arteries of the intra-abdominal segment in normal singleton pregnancies]

BACKGROUND

In the management of high risk pregnancies, blood flow measurements in the umbilical arteries (Aa. umb) have reduced perinatal morbidity and mortality. No consensus has been reached about the optimal location of measurements along the umbilical cord. The present study analyses the blood flow in both umbilical arteries where they pass by the fetal bladder.

PATIENTS AND METHODS

In 48 normal pregnancies, Doppler examinations were used to measure the pulsatility indices (PI). From the 20th week of pregnancy onward, the PI were measured once every four weeks in the intraabdominal segments of the right and the left Aa. umb. lateral to the fetal bladder. Measurements were also done in a free loop and at the placental insertion.

RESULTS

For all locations, normal ranges were calculated. The PI at all four sites decreased as the pregnancies were approaching term. In the III. trimester, the standard deviations of PI were smaller than in the II. trimester. The PI at the intraabdominal segment of the right and the left umbilical arteries turned out to be similar to each other and exceeded the values measured at the free loop and at the placental insertion respectively.

CONCLUSION

The intraabdominal segments of the umbilical arteries were defined as a new location for PI measurements. When adopting a fixed place of measurement, it is likely that the reproducibility of PI measurements will be increased.

DISCUSSION

The higher PI at the intraabdominal segment of the umbilical arteries are caused by the more central location compared to the placental insertion.

Transient receptor potential channels as molecular substrates of receptor-mediated cation entry

Calcium is a versatile multitarget intracellular second messenger in eukaryotic cells. In addition to calcium release from intracellular stores and influx via voltage- or ligand-operated channels, agonist-induced calcium entry constitutes one of the main pathways by which cytosolic calcium is elevated. Receptor-stimulated currents are initiated in response to agonist binding to G-protein-coupled receptors and to receptor tyrosine kinases. Within the past few years our knowledge about the molecular identity of receptor-stimulated channels has expanded substantially. Drosophila melanogaster visual transduction channels associated with the transient receptor potential (trp) and the trp-like (trpl) mutant visual phenotypes were the first members of this category of channels to be identified at the molecular level. Since then an entire mammalian gene family of TRP homologues has been discovered by homology cloning. Only now are we beginning to fully understand the functional roles of TRP channels in mammalian cells. We review recent findings in TRP channel research and discuss the role of these proteins for receptor-activated cation entry.

Receptor-mediated regulation of the nonselective cation channels TRPC4 and TRPC5

Mammalian transient receptor potential channels (TRPCs) form a family of Ca(2+)-permeable cation channels currently consisting of seven members, TRPC1-TRPC7. These channels have been proposed to be molecular correlates for capacitative Ca(2+) entry channels. There are only a few studies on the regulation and properties of the subfamily consisting of TRPC4 and TRPC5, and there are contradictory reports concerning the possible role of intracellular Ca(2+) store depletion in channel activation. We therefore investigated the regulatory and biophysical properties of murine TRPC4 and TRPC5 (mTRPC4/5) heterologously expressed in human embryonic kidney cells. Activation of G(q/11)-coupled receptors or receptor tyrosine kinases induced Mn(2+) entry in fura-2-loaded mTRPC4/5-expressing cells. Accordingly, in whole-cell recordings, stimulation of G(q/11)-coupled receptors evoked large, nonselective cation currents, an effect mimicked by infusion of guanosine 5'-3-O-(thio)triphosphate (GTPgammaS). However, depletion of intracellular Ca(2+) stores failed to activate mTRPC4/5. In inside-out patches, single channels with conductances of 42 and 66 picosiemens at -60 mV for mTRPC4 and mTRPC5, respectively, were stimulated by GTPgammaS in a membrane-confined manner. Thus, mTRPC4 and mTRPC5 form nonselective cation channels that integrate signaling pathways from G-protein-coupled receptors and receptor tyrosine kinases independently of store depletion. Furthermore, the biophysical properties of mTRPC4/5 are inconsistent with those of I(CRAC), the most extensively characterized store-operated current.

Evaluation of the impact of pharmacist's advice giving on the outcomes of self-medication in patients suffering from dyspepsia

The aim of this study was to investigate the outcomes of self-medication in patients suffering from dyspepsia by comparing changes in the Health related Quality of Life before and after self-medication of dyspeptic disorders. Another study objective was the quantitative and qualitative analysis of the pharmacist's advice-giving to patients with dyspepsia. Therefore the impact of the counselling by the pharmacist on the patient's health outcomes was surveyed and compared between study and control pharmacies. Moreover, the study analysed the influence of a special training on the services provided by the pharmacies with regard to self-medication. A beneficial effect of self-medication on the HRQoL of patients with dyspepsia on a weekly basis has been detected in the study. There is evidence that advice-giving and counselling by the pharmacists in self-medication have a measurable impact on self-medication outcomes. Moreover, the study reveals that patients value the information provided by the pharmacist. Pharmacists gathered the relevant and comprehensive information from the patients having dyspeptic symptoms and provided advice concerning OTC-drugs. Moreover, pharmacists frequently discussed the relevance of factors aggravating dyspeptic disorders such as lifestyle, drinking, smoking, and manner of nutrition with the patient. Training programs and treatment guidelines for the pharmacist seem to obtain a positive effect on his performance. The findings of the study substantiate the value of a pharmacist-controlled self-medication. The study results suggest that the quality of primary health care in self-medication would improve if pharmacists' involvement were even more intense.

Certification of highly complex safety-related systems

The BIA has now 15 years of experience with the certification of complex electronic systems for safety-related applications in the machinery sector. Using the example of machining centres this presentation will show the systematic procedure for verifying and validating control systems using Application Specific Integrated Circuits (ASICs) and microcomputers for safety functions. One section will describe the control structure of machining centres with control systems using "integrated safety." A diverse redundant architecture combined with crossmonitoring and forced dynamization is explained. In the main section the steps of the systematic certification procedure are explained showing some results of the certification of drilling machines. Specification reviews, design reviews with test case specification, statistical analysis, and walk-throughs are the analytical measures in the testing process. Systematic tests based on the test case specification, Electro Magnetic Interference (EMI), and environmental testing, and site acceptance tests on the machines are the testing measures for validation. A complex software driven system is always undergoing modification. Most of the changes are not safety-relevant but this has to be proven. A systematic procedure for certifying software modifications is presented in the last section of the paper.

A protein complex containing Inscuteable and the Galpha-binding protein Pins orients asymmetric cell divisions in Drosophila

BACKGROUND

In the fruit fly Drosophila, the Inscuteable protein localises to the apical cell cortex in neuroblasts and directs both the apical-basal orientation of the mitotic spindle and the basal localisation of the protein determinants Numb and Prospero during mitosis. Asymmetric localisation of Inscuteable is initiated during neuroblast delamination by direct binding to Bazooka, an apically localised protein that contains protein-interaction motifs known as PDZ domains. How apically localised Inscuteable directs asymmetric cell divisions is unclear.

RESULTS

A novel 70 kDa protein called Partner of Inscuteable (Pins) and a heterotrimeric G-protein alpha subunit were found to bind specifically to the functional domain of Inscuteable in vivo. The predicted sequence of Pins contained tetratrico-peptide repeats (TPRs) and motifs implicated in binding Galpha proteins. Pins colocalised with Inscuteable at the apical cell cortex in interphase and mitotic neuroblasts. Asymmetric localisation of Pins required both Inscuteable and Bazooka. In epithelial cells, which do not express inscuteable, Pins was not apically localised but could be recruited to the apical cortex by ectopic expression of Inscuteable. In pins mutants, these epithelial cells were not affected, but neuroblasts showed defects in the orientation of their mitotic spindle and the basal asymmetric localisation of Numb and Miranda during metaphase. Although localisation of Inscuteable in pins mutants was initiated correctly during neuroblast delamination, Inscuteable became homogeneously distributed in the cytoplasm during mitosis.

CONCLUSIONS

Pins and Inscuteable are dependent on each other for asymmetric localisation in delaminated neuroblasts. The binding of Pins to Galpha protein offers the intriguing possibility that Inscuteable and Pins might orient asymmetric cell divisions by localising or locally modulating a heterotrimeric G-protein signalling cascade at the apical cell cortex.

Increased expression and immunogenicity of sequence-modified human immunodeficiency virus type 1 gag gene

A major challenge for the next generation of human immunodeficiency virus (HIV) vaccines is the induction of potent, broad, and durable cellular immune responses. The structural protein Gag is highly conserved among the HIV type 1 (HIV-1) gene products and is believed to be an important target for the host cell-mediated immune control of the virus during natural infection. Expression of Gag proteins for vaccines has been hampered by the fact that its expression is dependent on the HIV Rev protein and the Rev-responsive element, the latter located on the env transcript. Moreover, the HIV genome employs suboptimal codon usage, which further contributes to the low expression efficiency of viral proteins. In order to achieve high-level Rev-independent expression of the Gag protein, the sequences encoding HIV-1(SF2) p55(Gag) were modified extensively. First, the viral codons were changed to conform to the codon usage of highly expressed human genes, and second, the residual inhibitory sequences were removed. The resulting modified gag gene showed increases in p55(Gag) protein expression to levels that ranged from 322- to 966-fold greater than that for the native gene after transient expression of 293 cells. Additional constructs that contained the modified gag in combination with modified protease coding sequences were made, and these showed high-level Rev-independent expression of p55(Gag) and its cleavage products. Density gradient analysis and electron microscopy further demonstrated that the modified gag and gag protease genes efficiently expressed particles with the density and morphology expected for HIV virus-like particles. Mice immunized with DNA plasmids containing the modified gag showed Gag-specific antibody and CD8(+) cytotoxic T-lymphocyte (CTL) responses that were inducible at doses of input DNA 100-fold lower than those associated with plasmids containing the native gag gene. Most importantly, four of four rhesus monkeys that received two or three immunizations with modified gag plasmid DNA demonstrated substantial Gag-specific CTL responses. These results highlight the useful application of modified gag expression cassettes for increasing the potency of DNA and other gene delivery vaccine approaches against HIV.

Physical, chemical, and biological evaluations of P760: a new gadolinium complex characterized by a low rate of interstitial diffusion

An original gadolinium chelate, termed P760, which diffuses through the vascular endothelium but at a much lower rate than nonspecific agents (NSA), is described. P760 is a gadolinium macrocyclic compound based on a DOTA structure that is substituted by hydrophilic bulky groups branched on the amino-carboxylic residues. The molecular weight is 5293, and the molecular volume, measured by light scattering, is 30 times higher (11.5 nm3) than that of gadolinium (Gd)-DOTA (0.38 nm3). The increase in molecular volume and weight has two consequences: a) higher relaxivity (r1; 24.7 mM-1.s-1 compared with 3.4 mM-1.s-1 for Gd-DOTA at 20 Mhz, 37 degrees C); and b) a lengthening of its transport rate through the endothelium. P760 presents a peculiar pharmacokinetic profile: at early times post injection, the blood concentrations are higher than those of Gd-DOTA, but after 20 minutes, the blood concentrations are equal for the two compounds. The body clearances of the products are identical (i.e., glomerular filtration rate). P760 molecules are large enough to have a restricted diffusion through the endothelium but, conversely, small enough to pass freely through the glomerular membrane. This limited extravasation has been observed in rabbits by magnetic resonance angiography or in investigations of tumor permeability. Further experimental imaging studies are needed to define the clinical interest of such properties.

Two different mechanisms for activation of cyclic PIP synthase: by a G protein or by protein tyrosine phosphorylation

The biosynthesis of the functional, endogenous cyclic AMP antagonist, prostaglandylinositol cyclic phosphate (cyclic PIP) is performed by the plasma membrane-bound enzyme cyclic PIP synthase, which combines prostaglandin E (PGE) and activated inositol phosphate (n-IP) to cyclic PIP. The Km values of the enzyme for the substrates PGE and n-IP are in the micromolar range. The plasma membrane-bound synthase is activated by fluoride, by the stable GTP analog GMP-PNP, by protamine or biguanide, by noradrenaline, and by insulin. The activation by protamine or biguanide and fluoride (10 mM) is additive, which may indicate the presence of two different types of enzyme, comparable to phospholipase Cbeta and phospholipase Cgamma. Plasma membrane-bound cyclic PIP synthase is inhibited by the protein tyrosine kinase inhibitor tyrphostin B46 with an IC50 of 1.7 microM. However, the solubilized and gel-filtrated enzyme is no longer inhibited by tyrphostin, indicating that the activity of cyclic PIP synthase is connected with the activity of a membrane-bound protein tyrosine kinase. Cyclic PIP synthase activity of freshly prepared plasma membranes is unstable. Upon freezing and rethawing of liver plasma membranes, this instability is increased about 2-fold. Protein tyrosine phosphatase inhibitors [vanadate, fluoride (50-100 mM)] stabilize the enzyme activity, but protease inhibitors do not, indicating that inactivation of the enzyme is connected with protein tyrosine dephosphorylation. Cyclic PIP synthase is present in all tissues tested, like brain, heart, intestine, kidney, liver, lung, skeletal muscle, spleen, and testis. Apart from liver, cyclic PIP synthase activity in most tissues is rather low, but it can be increased up to 5-fold when protein tyrosine phosphatase inhibitors like vanadate are present in the homogenization buffer. Preincubation of cyclic PIP synthase of liver plasma membranes with the tyrosine kinase src kinase causes a 2-fold increase of cyclic PIP synthase activity, though this is certainly not the physiological role played by src kinase in intact cells. The data indicate that cyclic PIP synthase can be activated by two separate mechanisms: by a G protein or by protein tyrosine phosphorylation.

Bazooka recruits Inscuteable to orient asymmetric cell divisions in Drosophila neuroblasts

Asymmetric cell divisions can be generated by the segregation of determinants into one of the two daughter cells. In Drosophila, neuroblasts divide asymmetrically along the apical-basal axis shortly after their delamination from the neuroectodermal epithelium. Several proteins, including Numb and Miranda, segregate into the basal daughter cell and are needed for the determination of its correct cell fate. Both the apical-basal orientation of the mitotic spindle and the localization of Numb and Miranda to the basal cell cortex are directed by Inscuteable, a protein that localizes to the apical cell cortex before and during neuroblast mitosis. Here we show that the apical localizaton of Inscuteable requires Bazooka, a protein containing a PDZ domain that is essential for apical-basal polarity in epithelial cells. Bazooka localizes with Inscuteable in neuroblasts and binds to the Inscuteable localization domain in vitro and in vivo. In embryos lacking both maternal and zygotic bazooka function, Inscuteable no longer localizes asymmetrically in neuroblasts and is instead uniformly distributed in the cytoplasm. Mitotic spindles in neuroblasts are misoriented in these embryos, and the proteins Numb and Miranda fail to localize asymmetrically in metaphase. Our results suggest that direct binding to Bazooka mediates the asymmetric localization of Inscuteable and connects the asymmetric division of neuroblasts to the axis of epithelial apical-basal polarity.

Localization of the Wilson's disease protein in human liver

BACKGROUND & AIMS

Wilson's disease is an autosomal-recessive disorder of copper metabolism that results from the absence or dysfunction of a copper-transporting P-type adenosine triphosphatase that leads to impaired biliary copper excretion and disturbed holoceruloplasmin synthesis. To gain further insight into the role of the Wilson's disease protein in hepatic copper handling, its localization in human liver was investigated.

METHODS

By use of a specific antibody, localization of the Wilson's disease protein was studied in liver membrane fractions and liver sections by immunoblotting, immunohistochemistry, and double-label confocal scanning laser microscopy.

RESULTS

The 165-kilodalton protein, found by immunoblotting, was most abundant mainly in isolated plasma membrane fractions enriched in canalicular domains. Immunohistochemistry revealed intracellular punctuate staining of hepatocytes in certain regions of the liver, whereas a canalicular membrane staining pattern was observed in other regions. Double-labeling studies showed that in the latter regions the transporter is present mainly in vesicular structures just underneath the canalicular membrane that are positive for markers of the trans-Golgi network. A weak staining of the canalicular membrane, identified by staining for P-glycoprotein, was observed.

CONCLUSIONS

These results show that in human liver the Wilson's disease protein is predominantly present in trans-Golgi vesicles in the pericanalicular area, whereas relatively small amounts of the protein appear to localize to the canalicular membrane, consistent with a dual function of the protein in holoceruloplasmin synthesis and biliary copper excretion.

Interaction of the copper chaperone HAH1 with the Wilson disease protein is essential for copper homeostasis

The delivery of copper to specific sites within the cell is mediated by distinct intracellular carrier proteins termed copper chaperones. Previous studies in Saccharomyces cerevisiae suggested that the human copper chaperone HAH1 may play a role in copper trafficking to the secretory pathway of the cell. In this current study, HAH1 was detected in lysates from multiple human cell lines and tissues as a single-chain protein distributed throughout the cytoplasm and nucleus. Studies with a glutathione S-transferase-HAH1 fusion protein demonstrated direct protein-protein interaction between HAH1 and the Wilson disease protein, which required the cysteine copper ligands in the amino terminus of HAH1. Consistent with these in vitro observations, coimmunoprecipitation experiments revealed that HAH1 interacts with both the Wilson and Menkes proteins in vivo and that this interaction depends on available copper. When these studies were repeated utilizing three disease-associated mutations in the amino terminus of the Wilson protein, a marked diminution in HAH1 interaction was observed, suggesting that impaired copper delivery by HAH1 constitutes the molecular basis of Wilson disease in patients harboring these mutations. Taken together, these data provide a mechanism for the function of HAH1 as a copper chaperone in mammalian cells and demonstrate that this protein is essential for copper homeostasis.

P760 and P775: MRI contrast agents characterized by new pharmacokinetic properties

RATIONALE AND OBJECTIVES

In this paper we discuss novel MR imaging blood pool agents characterized by new pharmacokinetic properties.

METHODS

The pharmacokinetics of the products were studied in a rabbit model. The potential of these new products was demonstrated in experimental MR imaging.

RESULTS AND CONCLUSION

Three main classes of blood pool agents have been defined and characterized according to their pharmacokinetic properties: low diffusion agents, rapid clearance blood pool agents, slow clearance blood pool agents. Each kind of blood pool agent is expected to have different diagnostic applications.

Mental health assessment of young children in a managed care environment

Managed behavioral health care is widely perceived as a threat to traditional practice in mental health at the expense of quality care. Although such assertions by mental health providers may prove to be justified in certain circumstances, they should not serve to obscure the quite reasonable public health motives behind managed care and the favorable effect managed care organizations may ultimately have on clinical decision-making and practice. By compelling practitioners to more clearly articulate the basis for their clinical judgments and by increasingly requiring evidence to support such judgments, they discourage the application of ill-considered, sometimes inappropriate, and occasionally iatrogenic evaluation and treatment interventions. In the future, there is significant danger that developmental assessment and treatment procedures for young children will be inappropriately constrained and diminished. This is especially true if those who work with young children fail to use the tools available to them to make the case for the best of current practice, whether a clearly stated clinical rationale, a formal appeal, the advocacy of our health professions, or applied clinical services research. The practices of our health plans need to be understood by providers in the context of managed care values. Primitive systems should not be confused with corrupt systems. Although undoubtedly the latter exist, they do not necessarily predominate. Within a managed care context and with due respect to managed care assumptions, it is possible to bring utilization management and contemporary practices in developmental assessment into closer alignment, ultimately to the benefit of children who need them.

Hepatocyte-specific localization and copper-dependent trafficking of the Wilson's disease protein in the liver

Wilson's disease is an inherited disorder of copper metabolism characterized by hepatic cirrhosis and neuronal degeneration. In this current study, a polyclonal antiserum specific for the Wilson's disease ATPase was used to examine the hepatic expression of this protein. Immunoblot analysis of lysates from human and rat liver detected a single 165-kDa protein, which by immunofluorescence was present only in hepatocytes and localized predominantly to the trans-Golgi network and exclusively in this compartment under low hepatic copper concentrations. Although hepatic copper concentration had no effect on the steady-state levels of the Wilson's disease protein, copper administration in vivo resulted in redistribution of this protein to a cytoplasmic vesicular compartment localized toward the hepatocyte canalicular membrane. The relative abundance of the Wilson's disease protein in the liver was found to be greatest in the fetus before the onset of biliary copper excretion. Taken together, these studies reveal a novel posttranslational mechanism of copper homeostasis in vivo consistent with the proposed function of the Wilson's disease protein in holoceruloplasmin biosynthesis and biliary copper excretion and of relevance to the broad clinical heterogeneity observed in this disease.

Genetic disorders of membrane transport. IV. Wilson's disease and Menkes disease

Copper is an essential transition metal that permits the facile transfer of electrons in a series of critical biochemical pathways. Menkes disease and Wilson's disease are inherited disorders of copper metabolism resulting from the absence or dysfunction of homologous copper-transporting ATPases that reside in the trans-Golgi network of all cells. Despite striking differences in the clinical presentation of these two diseases, the respective ATPases function in precisely the same manner within the cell and the unique clinical features of each disease are entirely the result of the tissue-specific expression of each protein. Elucidation of the basic defect in these rare genetic disorders has provided a valuable heuristic paradigm for understanding the mechanisms of cellular copper homeostasis.