[Fabry nephropathy in a female with superposed IgA glomerulonephritis]

BACKGROUND

In Anderson-Fabry disease (AFd), the kidney is affected in all hemizygous males and in some heterozygous females. Female carriers can present subtle renal abnormalities due to glycosphingolipid (GSL) accumulation within renal cells. Renal biopsy is rarely performed in female Fabry patients because clinical renal manifestations are usually lacking. However, female carriers can accumulate GSL in their renal cells despite the absence of clinically evident kidney disease.

CASE REPORT

We performed a kidney biopsy in a 52-year-old female patient, a Fabry disease carrier. The patient showed normal glomerular filtration rate, persistent microhematuria and proteinuria (about 1.7 g/24 hr), cornea "verticillata", and evident left ventricular hypertrophy. The molecular study documented a missense mutation R227Q in exon 5 of the alpha-galactosidase A gene. Optical microscopy showed electron-dense mesangial deposits due IgA glomerulonephritis, as confirmed by immunofluorescence. We decided to start therapy with angiotensin-converting enzyme inhibitors (ACE-I). After 8 months of treatment, the patient demonstrated proteinuria of 0.9 g/24 hr. To decide when to start treatment using enzyme replacement therapy (ERT) with human recombinant GAL A (Fabrazyme), we decided to perform an electron microscopy study of the renal biopsy. The renal ultrastructural findings were typical GSL inclusions in all kinds of glomerular cells, in tubular epithelial cells and in endothelial cells of interstitial capillaries, confirming the hypothesis of Fabry nephropathy. Consequently, Fabrazyme was given at a standard dose of 1 mg/kg every 2 weeks. After 24 months of combined treatment (ACE-I-Fabrazyme), proteinuria decreased to 0.2 g/24 hr.

CONCLUSIONS

The importance of performing the ultrastructural examination of the kidney biopsy is stressed, especially in heterozygous Fabry patients to evaluate the need to treat them with ERT and to evaluate the degree of renal involvement.

Electrophysiological approach to the study of essential tremor in children and adolescents

Surface electromyography and accelerometry provide essential information on the neurophysiological characteristics of essential tremor. There are many reports on neurophysiological features in adult-onset essential tremor, but to our knowledge there have been no similar investigations of essential tremor in children. We conducted a neurophysiological study of nine children, six males and three females, with definite essential tremor. They were subdivided into two groups according to age: a 'children's group', consisting of four patients aged from 7 to 12 years, and an 'adolescent group', consisting of five patients aged from 14 to 16 years. Finger tremor as opposed to hand tremor was studied. In children the mean tremor frequency was 5.3 Hz (SD 0.5) with arms extended, which increased to 8.2 Hz (SD 1.5) when we added a mass of 300 g. In adolescents the mean tremor frequency was 9.0 Hz (SD 1.4) with arms extended, and 7.2 Hz (SD 1.8) with added mass. We discuss several hypotheses to find an explanation for these results.

Microscopic two-dimensional lattice model of dimer granular compaction with friction

We study by Monte Carlo simulation the compaction dynamics of hard dimers in two dimensions under the action of gravity, subjected to vertical and horizontal shaking, considering also the case in which a friction force acts for horizontal displacements of the dimers. These forces are modeled by introducing effective probabilities for all kinds of moves of the particles. We analyze the dynamics for different values of the time tau during which the shaking is applied to the system and for different intensities of the forces. It turns out that the density evolution in time follows a stretched exponential behavior if tau is not very large, while a power law tail develops for larger values of tau. Moreover, in the absence of friction, a critical value tau(*) exists, which signals the crossover between two different regimes: for tau<tau(*) the asymptotic density scales with a power law of tau, while for tau>tau(*) it reaches logarithmically a maximal saturation value. Such behavior smears out when a finite friction force is present. In this situation the dynamics is slower and lower asymptotic densities are attained. In particular, for significant friction forces, the final density decreases linearly with the friction coefficient. We also compare the frictionless single tap dynamics to the sequential tapping dynamics, observing in the latter case an inverse logarithmic behavior of the density evolution, as found in the experiments.

Immunohistochemical study of muscle biopsy in children with cerebral palsy

Muscle biopsy was examined in 20 children with cerebral palsy, using immunohistochemical methods for marker of denervation neural cell adhesion molecules (N-CAM) in addition to standard techniques. Histological and histochemical study showed mild myopathic changes, type 1 predominance, and type 1 and type 2 hypotrophy, in accord with previous observations. Immunohistochemical study showed N-CAM expression in most biopsies (15/20), usually in scattered fibers, whereas in four patients aged less than 6 years it was expressed in grouped fibers. Our study supports the hypothesis of motor unit remodeling as a consequence of spasticity, especially in early phases of the disease.

Stretched exponential relaxation in a diffusive lattice model

We studied the single dimer dynamics in a lattice diffusive model as a function of particle density in the high densification regime. The mean square displacement is found to be subdiffusive both in one and two dimensions. The spatial dependence of the self-part of the van Hove correlation function displays as a function of r a single peak and signals a dramatic slow down of the system for high density. The self-intermediate scattering function is fitted to the Kohlrausch-Williams-Watts law. The exponent beta extracted from the fits is density independent while the relaxation time tau follows a scaling law with an exponent 2.5.

HLA-DRB1*1501 and response to copolymer-1 therapy in relapsing-remitting multiple sclerosis

BACKGROUND

Copolymer 1 (Cop-1) is a random synthetic amino acid copolymer, effective in the treatment of the relapsing-remitting form of MS (RRMS). In vitro and in vivo studies suggest that the mechanism of Cop-1 involves its binding to major histocompatibility complex class II molecules as an initial step.

OBJECTIVE

To assess a possible relationship between human leukocyte antigen (HLA) alleles and response to Cop-1 therapy.

METHODS

Eighty-three patients with RRMS, 44 treated with Cop-1 and 39 with interferon beta-1a (IFNbeta-1a) for 2 years, were typed by molecular methods for HLA class II genes and subgrouped according to clinical outcome.

RESULTS

Data have shown a possible positive correlation between presence of DRB1*1501 and response to Cop-1 therapy (p = 0.008). No relationship between HLA alleles and therapy has been found in IFNbeta-1a treated patients.

CONCLUSIONS

Results suggest that DRB1*1501 might be relevant for the clinical outcome in Cop-1 treated patients and, if confirmed in larger studies, it could be helpful in the selection of RRMS patients for different therapeutic options.

[Abdominal actinomycosis and retroperitoneal fibrosis. Considerations on a clinical case]

Abdominal actinomycosis is a rare disease which often resembles an acute suppurative infection or/and abdominal tumour causing abscesses, fistulas and massive fibrosis. The preoperative diagnosis is difficult and surgical exploration is always needed because of major involvement of visceral and retroperitoneal structures. The disease can be diagnosed with certainty only on the basis of findings of bacterial colonies in histopathologic sections and typical sulphur grains in secretions from fistulas. The authors describe a case of abdominal actinomycosis involving the caecum and right colon, causing extensive retroperitoneal fibrosis and a fistula tract with an external cutaneous orifice at the level of the right iliac crest. These features resembled an acute appendicitis at first, and several surgical explorations were required before a correct diagnosis could be achieved. Abdominal actinomycosis can be treated by simple administration of antibiotics. With a correct diagnosis, medical therapy alone has proved effective in a substantial percentage of patients, thus avoiding the need for surgery, if important visceral or retroperitoneal structures are not involved. Abdominal actinomycosis always requires a careful differential diagnosis and must be considered in patients presenting abdominal tumours associated with abscesses and/or fistulas since early and efficient medical therapy, along with surgical intervention, where necessary, can lead to definitive recovery. Useful diagnostic tools are abdominal CT and selective FNAB.

Crohn disease: susceptibility and disease heterogeneity revealed by HLA genotyping

Predisposition to Crohn disease (CD) seems to be genetically determined but, though several reports on the matter, the association between HLA antigens and the disease is still controversial. PCR-SSP high resolution typing in 107 CD patients, and in subgroups selected according to clinical features, showed a positive association with the rare haplotype DRB1*07, DQB1*0303 both in the overall patients (p = 0.002; pc = ns) and in the subgroup of nonfistulized patients (p = 0.0008; pc = 0.032). Moreover, the protective role of the haplotype DRB1*03, DQB1*0201 (p = 0.029) was confirmed also in Italian patients, whereas no strong association with HLA class I alleles has been found. In addition, variability of the HLA alleles frequency in CD subgroups was observed, supporting the hypothesis of a genetic heterogeneity of the disease and suggesting that HLA alleles distribution in selected groups may allow to identify patients with probably different prognosis or associated complications.

Tissue-specific splicing of Omi stress-regulated endoprotease leads to an inactive protease with a modified PDZ motif

Omi is a human serine protease whose catalytic domain is homologous to a bacterial heat shock endoprotease (HtrA), a protein indispensable to the survival of bacteria at elevated temperatures. Omi is expressed ubiquitously, and its protein product is predominantly localized in the endoplasmic reticulum of mammalian cells. Here we present the genomic structure of Omi, consisting of eight exons located on human chromosome 2p12-p13. Furthermore, we describe an alternatively splice form of Omi (D-Omi) that is expressed predominantly in the kidney, colon, and thyroid. D-Omi lacks peptide sequence encoded by two exons (exons III and VII). The absence of exon VII leads to a protein with a modified PDZ domain unable to interact with a known partner, the Mxi2 protein. The absence of exon III affects the catalytic domain and leads to a protein with no detectable protease activity. Our studies suggest that D-Omi may have a unique role in the normal function of kidney, colon, and thyroid.

Mxi2, a splice variant of p38 stress-activated kinase, is a distal nephron protein regulated with kidney ischemia

Mxi2 is one of three known alternative spliced forms of the stress-activated mitogen-activated protein kinase p38 (CSBP). Mxi2 was originally identified as a Max-interacting protein and is the smallest member of the family of stress-activated kinases isolated to date. Mxi2 lacks most of the XI domain found in p38 and instead has a distinct COOH-terminal sequence of 17 amino acids. Here we present the genomic structure of the Mxi2/p38 locus on human chromosome 6q21.2/21.3 and establish the origin of the three spliced forms of p38. Using Mxi2-specific antibodies in mouse organs, we found the Mxi2 protein to be present exclusively in the kidney. Mxi2 is present predominantly in the distal tubule of the nephron and the level of the protein decreased during kidney ischemia-reperfusion. Stress signals or other known activators of the p38 pathway including MAP kinase-kinase 3 and MAP kinase-kinase 6 did not induce the kinase activity of Mxi2 using ATF-2 as a substrate. With the use of hybrid proteins encoding different portions of Mxi2 and p38 polypeptides, the different properties of Mxi2 can be assigned to its unique COOH terminus.

Characterization of a novel human serine protease that has extensive homology to bacterial heat shock endoprotease HtrA and is regulated by kidney ischemia

We report the isolation and characterization of a cDNA encoding the novel mammalian serine protease Omi. Omi protein consists of 458 amino acids and has homology to bacterial HtrA endoprotease, which acts as a chaperone at low temperatures and as a proteolytic enzyme that removes denatured or damaged substrates at elevated temperatures. The carboxyl terminus of Omi has extensive homology to a mammalian protein called L56 (human HtrA), but unlike L56, which is secreted, Omi is localized in the endoplasmic reticulum. Omi has several novel putative protein-protein interaction motifs, as well as a PDZ domain and a Src homology 3-binding domain. Omi mRNA is expressed ubiquitously, and the gene is localized on human chromosome 2p12. Omi interacts with Mxi2, an alternatively spliced form of the p38 stress-activated kinase. Omi protein, when made in a heterologous system, shows proteolytic activity against a nonspecific substrate beta-casein. The proteolytic activity of Omi is markedly up-regulated in the mouse kidney following ischemia/reperfusion.

Moyamoya disease in Italian monozygotic twins

We report white monozygotic twins with moyamoya disease (MMD) (adult ischemic type). Both had cerebral angiography, MRI, magnetic resonance angiography, SPECT, EEG, human leukocyte antigen (HLA) typing, evaluation of thrombophilia, and immunologic and karyotype analysis. The clinical features and HLA phenotypes described in Asian monozygotic twins with MMD were not found in our patients. However, genetic analysis revealed a homozygous state for C-->T (Ala-->Val substitution) in position 677 of the methylenetetrahydrofolate reductase-encoding gene.

In vivo construction of cDNA libraries for use in the yeast two-hybrid system

We describe a simple and efficient one-step method to make cDNA libraries using homologous recombination in yeast. cDNA from any source, together with a linear vector, is used to transform yeast. Through homologous recombination and gap repair, the cDNA is unidirectionally incorporated into the yeast expression vector in vivo. The cDNA-encoded proteins can then be screened for potential protein-protein interactions with a bait already present in the yeast. This method allows rapid construction and screening of cDNA libraries, even from extremely small amounts of mRNA, and can replace the use of conventional cDNA libraries.

In vivo construction of cDNA libraries for use in the yeast two-hybrid system

We describe a simple and efficient one-step method to make cDNA libraries using homologous recombination in yeast. cDNA from any source, together with a linear vector, is used to transform yeast. Through homologous recombination and gap repair, the cDNA is unidirectionally incorporated into the yeast expression vector in vivo. The cDNA-encoded proteins can then be screened for potential protein-protein interactions with a bait already present in the yeast. This method allows rapid construction and screening of cDNA libraries, even from extremely small amounts of mRNA, and can replace the use of conventional cDNA libraries.

Molecular cloning and characterization of a novel retinoblastoma-binding protein

We describe the isolation and characterization of a novel cDNA encoding a polypeptide that interacts in a yeast two-hybrid system as well as in mammalian cells with the retinoblastoma (RB) protein. This new protein, which we call Rim, consists of 897 amino acids, has two leucine zipper motifs, and has a LECEE sequence previously identified as an RB-binding domain. Rim also has an E1A/CtBP-binding motif and four putative nuclear localization signals. Rim mRNA is expressed ubiquitously at low levels in all human adult tissues tested and at much higher levels in several tumor cell lines. The Rim gene (HGMW-approved symbol RBBP8) is localized on human chromosome 18q11.2.

Molecular diagnosis of p53 mutations in gastric carcinoma by touch preparation

Thirty-one tumor samples from selected cases of gastric carcinoma were analyzed for mutations of the p53 tumor suppressor gene. Template DNA was prepared according to the touch preparation procedure, which allowed us to isolate clusters of neoplastic cells out of a stromal cellular background to be used as a template in the amplification of target exons of the p53 locus. In our present study, by polymerase chain reaction/single strand conformation polymorphism analysis we give evidence of p53 mutations occurring in the DNA-binding core domain of the protein (exons 5 through 9), which are clustered in stages III and IV of the disease (six mutations out of seventeen samples; 35%). No p53 mutations were detected in fourteen gastric cancer samples at I and II stages. Beside the use of conventional molecular scanning procedures, our study proposes the application of the touch preparation method to increase the detection of genetic alterations in human solid tumors.

Frequent somatic hypermutation of the 5' noncoding region of the BCL6 gene in B-cell lymphoma

The BCL6 gene encodes a zinc-finger transcription factor and is altered by chromosomal arrangements in its 5' noncoding region in approximately 30% of diffuse large-cell lymphoma (DLCL). We report here that, in 22/30 (73%) DLCL and 7/15 (47%) follicular lymphoma (FL), but not in other tumor types, the BCL6 gene is also altered by multiple (1.4 x 10(-3) -1.6 x 10(-2) per bp), often biallelic, mutations clustering in its 5' noncoding region. These mutations are of somatic origin and are found in cases displaying either normal or rearranged BLC6 alleles indicating their independence from chromosomal rearrangements and linkage to immunoglobulin genes. These alterations identify a mechanism of genetic instability in malignant B cells and may have been selected during lymphomagenesis for their role in altering BCL6 expression.

Transcriptional modulation of the human intercellular adhesion molecule gene I (ICAM-1) by retinoic acid in melanoma cells

Retinoids play an important role as differentiating agents in a variety of normal and neoplastic cells and have been reported to induce ICAM-1 levels in melanomas, a phenomenon that we confirm in this paper. The effects of retinoids on gene expression usually involve the binding of specific retinoic acid receptor trans-acting factors (RARs) with their ligands, which then interact with specific target sites, the retinoic acid responsive elements (RAREs) present in the promoters of responsive genes. In the case of ICAM-1, we have cloned and analyzed the proximal regulatory region of the human gene. We show that the ICAM-1 promoter is RA-inducible, that it contains a putative consensus RARE (GGGTCATCGCCCTGCC), which binds in vitro RAR alpha complemented with RXRs, and that mutation of the RARE abrogates promoter responsiveness to RA. These studies allow ICAM-1 to be added to the list of genes transcriptionally activated by RA acting through an RARE element.

POEMS syndrome: clinical, pathological and immunological study of a case

A young Italian woman with a POEMS syndrome is described. The patient had a plasma cell dyscrasia without clinical or laboratory evidence of multiple myeloma. The phenotypic analysis of bone marrow cells and peripheral blood lymphocytes revealed a normal pattern. The immunological study of CSF showed high levels of interleukin-6, whereas this cytokine was not detectable in the serum. Electrophysiological studies and sural nerve biopsy showed a mixed, demyelinating-axonal sensorimotor neuropathy with marked loss of large myelinated fibres. Long-term treatment with prednisone gave some clinical improvement.

TPA-induced differentiation of human rhabdomyosarcoma cells involves dephosphorylation and nuclear accumulation of mutant P53

Previous studies have shown that human rhabdomyosarcoma cells are induced to differentiate by TPA, in the absence of appreciable alterations of the muscle regulatory genes and their products (1). The question was addressed whether the tumor suppressor p53 could be a target of TPA action in these cells. Genomic analysis by a Polymerase Chain Reaction/Single-Strand Conformation Polymorphism (PCR/SSCP) and direct sequencing indicate the presence of a mutation in exon VII at codon 248 (C to T transition) and a loss of heterozygosity of p53 gene in human rhabdomyosarcoma cell line (RD). It is here shown that transcription of p53 mRNA strongly decreases in RD cells induced to growth arrest and differentiate by TPA treatment. In these cells immunoprecipitation and immunoblot analysis show that both synthesis and total cellular concentration of the protein are also reduced by TPA. Nevertheless nuclear p53 accumulation is at much higher extent, whereas 32P-orthophosphate labelling, followed by immunoprecipitation, demonstrates a decrease of phosphorylation of both cytoplasmic and nuclear p53. These results indicate that TPA causes a number of alterations of mutant p53, likely mediated through a protein kinase C dependent mechanism, which might impair the transforming ability of mutant p53 in growth-arrested and differentiating RD cells.