A frameshift variant in the COL5A1 gene in a cat with Ehlers-Danlos syndrome.

Ehlers-Danlos syndrome (EDS) is a group of heritable connective tissue disorders caused by defective collagen synthesis or incorrect assembly of the collagen triple helical structure. EDS is characterised by joint hypermobility, skin hyperextensibility, abnormal scarring, poor wound healing and tissue friability. Human EDS may be caused by variants in several different genes including COL5A1, which encodes the collagen type V alpha 1 chain. For the present study we investigated a 1.5-year-old, spayed female, domestic shorthair cat with EDS. The affected cat showed multiple recurrent skin tears, hyperextensibility of the skin and joint abnormalities. We obtained whole genome sequencing data from the affected cat and searched for variants in candidate genes known to cause EDS. We detected a heterozygous single base-pair deletion in exon 43 of the COL5A1 gene, namely c.3420delG. The deletion was predicted to result in a frameshift and premature stop codon: p.(Leu1141SerfsTer134). Sanger sequencing confirmed that the variant was present in the affected cat and absent from 103 unaffected cats from different breeds. The variant was also absent from a Burmese cat with EDS. Based on knowledge about the functional impact of COL5A1 variants in other species, COL5A1:c.3420delG represents a compelling candidate causative variant for the observed EDS in the affected cat.

Dimeric IVIG contains natural anti-Siglec-9 autoantibodies and their anti-idiotypes.

BACKGROUND: Intravenous immunoglobulin (IVIG) preparations are increasingly used for the treatment of autoimmune and chronic inflammatory diseases. Naturally occurring autoantibodies against Siglec-9 and Fas are thought to contribute to the anti-inflammatory effects of IVIG via cell death regulation of leukocytes and tissue cells. Dimeric IVIG fractions are suspected to contain idiotypic (Id)-anti-idiotypic complexes of antibodies, which might also include anti-Siglec-9 and anti-Fas autoantibodies. METHODS: Dimeric IVIG fractions were separated from monomeric IVIG by size-exclusion chromatography and remonomerized by low pH treatment. Binding studies of total, monomeric, and dimeric IVIG were performed using surface plasmon resonance and flow cytometry on primary human neutrophils. RESULTS: Anti-Siglec-9 and anti-Fas autoantibodies were contained in both monomeric and dimeric IVIG fractions, but anti-Siglec-9 antibodies were highly enriched in dimeric IVIG. The propensity to engage in dimer formation was paratope dependent. IVIG binding to Siglec-9 was specific and sialylation independent. Interestingly, we detected anti-idiotypic antibodies (anti-Ids) against anti-Siglec-9 autoantibodies in dimeric, but not in monomeric fractions of IVIG. CONCLUSIONS: Our study supports the concept that idiotype-anti-idiotype (Id-anti-Id) interactions contribute to the dimer formation in IVIG preparations. To our knowledge, this is the first description of Id-anti-Id dimers of death receptor-specific antibodies in IVIG. Such Id-anti-Id interactions might determine the activity of immunomodulatory antibodies present both in IVIG and the patient.

Induction and prevention of chondrocyte hypertrophy in culture.

Primary chondrocytes from whole chick embryo sterna can be maintained in suspension culture stabilized with agarose for extended periods of time. In the absence of FBS, the cells remain viable only when seeded at high densities. They do not proliferate at a high rate but they deposit extracellular matrix with fibrils resembling those of authentic embryonic cartilage in their appearance and collagen composition. The cells exhibit many morphological and biochemical characteristics of resting chondrocytes and they do not produce collagen X, a marker for hypertrophic cartilage undergoing endochondral ossification. At low density, cells survive in culture without FBS when the media are conditioned by chondrocytes grown at high density. Thus, resting cartilage cells in agarose cultures can produce factors required for their own viability. Addition of FBS to the culture media leads to profound changes in the phenotype of chondrocytes seeded at low density. Cells form colonies at a high rate and assume properties of hypertrophic cells, including the synthesis of collagen X. They extensively deposit extracellular matrix resembling more closely that of adult rather than embryonic cartilage.

In vitro comparison of the complement-scavenging capacity of different intravenous immunoglobulin preparations.

BACKGROUND AND OBJECTIVES: Complement inhibition is considered important in the mechanism of action of intravenous immunoglobulin (IVIG) in a number of inflammatory and autoimmune disorders. The capacity of different IVIG preparations to 'scavenge' activated C3 and thereby inhibit complement activation was assessed by a new in vitro assay. MATERIALS AND METHODS: Diluted human serum as a complement source, with or without addition of different concentrations of IVIG, was incubated in microtitre plates coated with heat-aggregated human IgG. Complement scavenging was measured by detecting reduced C3 binding and determining fluid phase C3b-IgG complex formation. Complement activation induced by the IVIG preparations was measured as C5a formation. RESULTS: All IVIG preparations exhibited a dose-dependent inhibition of C3b deposition, correlating strongly with binding of C3b to fluid-phase IgG, but the extent of complement scavenging varied considerably between different IVIG preparations. At an IVIG concentration of 0.9 mg/ml, the inhibition of C3b deposition ranged from 72 +/- 16% to 22 +/- 4.1%. The reduction of C3b deposition on the complement-activating surface was not due to IVIG-induced complement activation in the fluid phase, as shown by the low C5a formation in the presence of serum. CONCLUSION: In vitro analysis allows comparison of the complement-inhibitory properties of IVIG preparations. The extent of complement scavenging varies between the products.

Isolation and characterization of rough endoplasmic reticulum associated with mitochondria from normal rat liver.

A subfraction of rough endoplasmic reticulum (RER) characterized by its close association with mitochondria (MITO) was isolated from low speed pellets of normal rat liver homogenate under defined ionic conditions. This fraction enriched in MITO-RER complexes contained 20% of cellular RNA, 20% of glucose-6-phosphatase and 47% of cytochrome c oxidase activities. Morphologically, the isolated MITO-RER complexes closely resembled physiological associations between the two organelles commonly seen in intact liver. Partial dissociation of RER from mitochondria of the MITO-RER fraction was achieved by either EDTA (0.5 mM) or by hypotonic/hypertonic treatment of MITO-RER complexes. With the latter procedure approx. 70% of RER (RERmito) with 50% of ribosomes still attached could be separated from the inner compartments of mitochondria. This RERmoto exhibited a higher glucose-6-phosphatase activity than RER isolated as rough microsomes from the postmitochondrial supernatant. Isopycnic centrifugation on linear metrizamide gradients revealed that the mitochondria-associated part of RER corresponds to the high density, ribosome-rich subfraction of rough microsomes isolated in cation-free sucrose solution. The combined data demonstrate that a morphologically and biochemically distinct portion of RER is associated with mitochondria and support the concept of considerable intracellular heterogeneities in distribution of enzymes and enzyme systems along the lateral plane of the endoplasmic reticulum membrane system.

Enteric infections and diarrhea in human immunodeficiency virus-infected persons: prospective community-based cohort study. Swiss HIV Cohort Study.

BACKGROUND: Persons infected with human immunodeficiency virus (HIV) are at increased risk for diarrhea and enteric infections. We studied (1) the epidemiology of enteric pathogens associated with diarrhea, (2) the diagnostic yield of stool examination and endoscopic evaluation, (3) risks to develop diarrhea, and (4) the impact of diarrhea on patients' survival. METHODS: A total of 1933 participants in the Swiss HIV Cohort Study were prospectively followed up for a median of 25.5 months. A total of 560 diarrheal episodes were evaluated by standardized stool examination. Endoscopic evaluation was performed in 25% of patients with chronic diarrhea. RESULTS: The incidence of diarrhea was 14.2 per 100 person-years (95% confidence interval, 13.0-15.4). Among patients with CD4 cell counts below 0.05 x 10(9)/L, the probability to develop diarrhea within 1, 2, and 3 years was 48.5%, 74.3%, and 95.6%, respectively. The risk to develop diarrhea was increased among patients with severe immunodeficiency, homosexual men, and patients taking antiretroviral therapy. Pneumocystis carinii chemoprophylaxis did not reduce the risk of diarrhea. Diarrhea was an independent negative predictor of survival. Enteric pathogens were detected in 16.5% of 212 acute diarrheal episodes and in 46% of 348 chronic diarrheal episodes. The sensitivity of histological and stool examination was similar except for the diagnosis of intestinal cytomegalovirus infection and leishmaniasis, which required invasive evaluation. CONCLUSIONS: Intestinal infections were diagnosed in less than 50% of chronic diarrheal episodes. The prevalence of enteric pathogens tended to decrease during the observation period, possibly because of improved antiretroviral therapy. Endoscopic evaluation did not improve the diagnostic yield compared with stool examination except for the diagnosis of cytomegalovirus enteritis and leishmaniasis.

Immunoglobulin-mediated shifting of immune complexes to increased complement-dependent solubility and immunoadherence.

The effect of a monomeric polyclonal polyspecific IgG preparation (mIgG) for i.v. use on the capacity of fresh normal human serum (NHS) to inhibit precipitation of immune complexes of tracer-labeled bovine serum albumin (BSA) and anti-BSA (aBSA) rabbit antibody was investigated. Relative to heat-inactivated serum which showed no capacity to inhibit immune complex precipitation (CIICP), fresh NHS at a final dilution of 1:3 or 1:2 showed a 12 and 46% CIICP, respectively, with a BSA:aBSA ratio at equivalence. Addition of incremental amounts of mIgG dose-dependently enhanced CIICP of NHS to reach 63 and 90%, respectively, at a concn of 13.0 mg/ml mIgG. Human serum albumin instead of mIgG had no influence on CIICP of NHS indicating that the phenomenon was not dependent on non-specific protein-protein interactions. Although minimal amounts of BSA cross-reactivity could be demonstrated in mIgG, the extent of this activity was too small to explain the CIICP-supporting effect of mIgG as determined by comparing the effect of mIgG and aBSA serum on CIICP of fresh serum. Furthermore, absorption of mIgG on BSA-Sepharose did not lead to impairment of its CIICP-supporting effect. A direct binding of tritium-labeled mIgG (3H-mIgG) to either insoluble BSA:aBSA complexes or latex-bound IgG (IgG-latex) was found. Incubation of 2.7 micrograms 3H-mIgG with 90 micrograms IgG-latex resulted in a specific binding of 5.2% of the labeled compound. Such binding could be inhibited by unlabeled mIgG. Binding of mIgG was mediated through the Fab as well as the Fc part of the molecules: the 3H-Fc as well as the 3H-Fab fragment of mIgG bound to IgG-latex. The extent of binding of Fc was more than twice that of Fab and amounted to 70-90% of the binding found with intact mIgG. In an immune adherence hemagglutination system that depends on the interaction of complement-reacted immune complexes with C3b receptor-bearing erythrocytes, evidence was obtained that the mIgG preparation facilitated fixation of C3b to performed BSA:aBSA complexes. Addition of 1.45 mg/ml mIgG reduced the quantity of antigen-complexed C3b-bearing aBSA antibodies required to show a given agglutination by a factor of 3-4. We conclude that the facilitating effect of high doses of mIgG on complement-dependent CIICP of NHS and on immune adherence hemagglutination is the amplifying effect of complement after an initial interaction of antigen-nonspecific polyclonal polyspecific IgG with antigen-reacted antibody.

Mutational analysis of the first 14 exons of the adenomatous polyposis coli (APC) gene.

In the present study, the polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) technique has been applied to the mutation analysis of the adenomatous polyposis coli (APC) gene. We examined the first 14 exons of the APC gene in 46 polyposis coli patients. Five germline mutations were observed, including a single-nucleotide substitution and small (1-4 bp) deletions leading, in 4 cases, to a stop codon. A missense mutation in exon 3 and a 1 bp deletion in exon 4 of the APC gene were observed in patients presenting with the attenuated form of FAP.

Human serum induced opsonization of immunoglobulin G-coated polystyrene microspheres with complement components C3 and C4 as measured by flow cytometry.

Human IgG-coated polystyrene microspheres (IgG-ms) were incubated with human serum followed by biotinylated monoclonal anti-C3d or anti-C4d antibody, and phycoerythrin-streptavidin. The intensity of fluorescence was measured by flow cytometry and corresponds to the amount of deposited C3 and C4. Binding of C3 and C4 was dependent on the activation of the classical pathway of complement and on the amount of IgG adsorbed to the particles. No deposition was observed on control particles coated with bovine serum albumin or ovalbumin. Incubation of constant amounts of IgG-ms with increasing amounts of normal human serum (NHS) resulted in a dose-dependent increase in C3 deposition. The same result was found for C4 deposition at moderate NHS dilutions, but less C4 was detectable using a higher input of NHS. Half-maximum C3 and C4 deposition was observed at a mean serum dilution of 1/114 and 1/520, respectively (n = 26). No correlation was found between C4 or C3 deposition and either total C4 and C3 serum concentrations as measured by nephelometry or complement-mediated lysis of antibody-coated sheep red blood cells. Reduced or absent C4 or C3 deposition was found in the sera of patients with low amounts or deficiencies of components involved early in classical complement pathway activation whereas essentially normal C4 or C3 deposition was obtained with the sera of patients with deficiencies in components of the membrane attack complex. With this simple and specific functional assay using stable reagents an altered function of early components of the classical pathway of complement may be quickly and reliably detected in routine diagnostic laboratories. Moreover, such opsonized and well characterized particles may be useful in assays of phagocytic cell function.

Surface labeling of human platelets by reductive methylation.

A simple, reproducible method for the specific labeling of the surface proteins of human platelets with tritium is described. The labeled platelets were analyzed by two-dimensional gel electrophoresis (isoelectric focusing/sodium dodecyl sulfate-polyacrylamide gel electrophoresis) followed by fluorography and the results compared with those obtained by conventional methods. Reductive methylation gave an intense labeling of membrane glycoproteins. There was no cross-linking of the labeled membrane proteins by formaldehyde nor could clear evidence be found that inner proteins were labeled by permeation of the reagents through the plasma membrane. As well as previously described platelet membrane glycoproteins, several others could be detected that were not invariable seen using labeling techniques.

Reconstituted high density lipoprotein (rHDL) modulates platelet activity in vitro and ex vivo.

A reconstituted high density lipoprotein (rHDL) prepared for clinical use was tested for its influence on platelet activity modulated by various stimuli. In a first series of in vitro experiments, rHDL was added to blood in a concentration series, and platelet rich plasma (PRP) was isolated. Platelets were stimulated with arachidonic acid, collagen, epinephrine or ADP, and platelet aggregation was assessed. rHDL mediated a dose dependent inhibition of the platelet activity. With purified platelets rHDL inhibited the release reaction induced by collagen, but not by thrombin, as measured by CD62P (P-Selectin) expression on the plasma membrane. Ex vivo experiments were performed with PRP from volunteers, previously infused with 25 mg rHDL/kg body weight and 40 mg rHDL/kg body weight, respectively. Platelet activity in PRP was assessed before, and up to 30 h after the end of the rHDL infusion. A transient inhibition of the platelet aggregation induced by arachidonic acid and collagen was observed which was more pronounced in the group receiving 40 mg rHDL/kg body weight. In both groups of experiments, in vitro and ex vivo, the inhibition of the platelet activity was also dependent on the stimulus used.

Infantile systemic hyalinosis in siblings: clinical report, biochemical and ultrastructural findings, and review of the literature.

A boy presented at age 3.5 months with joint contractures, restlessness, and pain on handling. His skin was thickened and there were livid-red macular lesions over bony prominences. Infantile systemic hyalinosis (ISH) was diagnosed, a presumably autosomal recessive, progressive, and painful disorder of as yet unknown pathogenesis. Observation over three years confirmed the diagnosis as typical changes, such as nodules on both ears, pearly papules in the perinasal folds and on the neck, fleshy nodules in the perianal region, and gingival hypertrophy, developed. Skin lesions and painful joint contractures progressed in spite of intense physiotherapy, and at age 3, the child had marked motor disability. The central nervous system (CNS) appeared to be intact and the infant showed normal mental development. Radiologic findings included marked generalized osteopenia, osteolytic erosions in the metaphyses of the long bones, and cortical thinning. Electron microscopy of two skin biopsies demonstrated deposition of floccular amorphous substance that was abundant around, and appeared to originate from, small blood vessels in the dermis, partially interfering with collagen fiber formation. Lysosomal inclusions were not seen. Serum acid hyaluronidase activity was within the normal range, and the synthesis of hyaluronic acid and proteoglycans in cultured skin fibroblasts was similar to that of control cells. A younger sister presented at age two months with painful joint contractures and discrete livid-red macules over both malleoli, and showed a similar progression of the disorder over the first year of life. The diagnosis of ISH should be considered in infants and children presenting with painful joint contractures and skin lesions. The pathogenesis of this disabling and disfiguring disorder remains unclear. Our data confirm probable autosomal recessive inheritance, and do not support lysosomal storage, hyaluronidase deficiency, or a primary collagen disorder, but indicate that the amorphous material accumulating in the skin and articular soft tissues may originate from the blood circulation.

Reconstituted high density lipoprotein modulates adherence of polymorphonuclear leukocytes to human endothelial cells.

A reconstituted high density lipoprotein (rHDL) containing human apolipoprotein A-I and phosphatidylcholine was tested for its ability to modify polymorphonuclear leukocyte (PMN) adherence to endothelial cells (EC) in vitro. EC stimulation for 4 h with lipopolysaccharide (LPS) or tumor necrosis factor-alpha (TNF alpha) resulted in a four- to sixfold increase in PMN adherence. Concomitant stimulation of EC with LPS and rHDL virtually prevented the LPS-stimulated increase in PMN adherence. Changes in adherence were paralleled by alterations in adhesion molecule expression of EC. Concomitant EC stimulation with LPS and rHDL resulted in complete inhibition of the LPS-stimulated increase in expression of E-selectin and intercellular adhesion molecule 1 (ICAM-1). In contrast, rHDL reduced the TNF alpha-induced expression of adhesion molecules as well as the PMN adherence to TNF alpha-stimulated EC by approximately 10%. The CD11/CD18-mediated PMN adherence to EC as a consequence of PMN stimulation with calcium ionophore (A23187) was diminished in the presence of rHDL after 7 min incubation by 36.1 +/- 11.4% and after 15 min incubation by 45.1 +/- 7.4%. In addition, the A23187-stimulated increase in PMN adherence to fibrinogen-coated surfaces, mediated by CD11b/CD18, was virtually eliminated in the presence of rHDL and HDL, but not in the presence of apolipoprotein A-I or natural low density lipoprotein. FACS analysis showed that PMN treated with rHDL and subsequently washed were resistant to FMLP-induced CD11b/ CD18 up-regulation. In conclusion, these data indicate that rHDL decreases cell adhesion via two mechanisms: blocking LPS activity and modifying CD11b/CD18 up-regulation on PMN.

Product equivalence study comparing the tolerability, pharmacokinetics, and pharmacodynamics of various human immunoglobulin-G formulations.

In this randomized, double-blind, parallel-group study, a commercially available human immunoglobulin-G product, IVIG, was compared with two test formulations: (1) IVIG-N, which is a nanofiltered formulation of IVIG, and (2) IVIG-L, which is a nanofiltered, liquid, ready-for-use IgG formulation containing nicotinamide, L-proline, and L-isoleucine as stabilizers. Three groups of 10 healthy subjects each received a single 0.6 g/kg dose of one of the formulations infused over 3.5 to 6.8 hours, depending on the total volume to be infused. Blood samples were obtained over a 6-week period to assess pharmacokinetics, immunogenicity, and the pharmacodynamic effects on leukocytes and TNF-alpha. A blood sample was taken at 6 months for a viral safety check. Administrations were generally well tolerated with only one reference IVIG infusion stopped prematurely due to headache. The IgG Cmax and AUC over the 6-week blood sampling period from both test formulations satisfied equivalence criteria compared with the reference formulation. In subjects receiving IVIG-L, peak concentrations of the stabilizer nicotinamide ranged from 0.34 to 0.47 mmol/L and of nicotinamide-N-oxide from 0.03 to 0.04 mmol/L, which are below those reported to cause adverse events. During the infusion of IVIG, leukocyte counts initially declined from a baseline of 5.7 +/- 1.1 x 10(9)/L to 3.7 +/- 0.8 x 10(9)/L at 2 to 4 hours and returned to baseline by 24 hours. TNF-alpha levels, reflecting activation of the monocyte-macrophage system by the infused IVIG, rose from a baseline of 13 +/- 4 pg/mL to a peak of 272 +/- 324 pg/mL at 2 to 4 hours and returned to baseline by 24 hours. These patterns were generally similar for the test formulations, with the exception that the increase in TNF-alpha levels was dampened for IVIG-N, although this was not statistically significant. There was no evidence of immunogenicity or viral transmission from any of the formulations. Hence, these three formulations were generally well tolerated, yielded similar systemic exposure to IgG over a 6-week period after administration, and did not give rise to immunogenicity or viral safety concerns.

Niemann-Pick's disease. Clinical, biochemical and ultrastructural findings in a case of the infantile form.

A diagnosis of Niemann-Pick disease type A was made in a 6-month-old boy on the grounds of progressive psychomotor retardation, hepatosplenomegaly, typical foam cells in the bone marrow and a deficiency of sphingomyelinase in a liver biopsy. Typical ultrastructural changes in lysosomes were found in hepatocytes and in Schwann cells. In spite of the absence of gross morphological changes in the axons and in the myelin sheath of the peripheral nerve biopsy, the nerve conduction velocity in the patient was greatly reduced. The ultrastructural aspect of the lysosomal inclusion suggested the storage of a phospholipid. Biochemical analysis of the liver biopsy demonstrated an increased content of total phospholipid of which sphingomyelin made up for more than 60%. The significance of these data are discussed.

Generalized gangliosidosis: acid beta-galactosidase deficiency with early onset, rapid mental deterioration and minimal bone dysplasia.

This report concerns a 3-month-old girl with rapidly progressive psychomotor retardation, hepatomegaly, vacuolated lymphocytes, minimal bone dysplasia and normal excretion of acid mucopolysaccharides. A deficiency of acid beta-galactosidase was demonstrated in isolated leucocytes and in a liver biopsy. The diagnosis of generalized gangliosidosis due to deficiency of beta-galactosidase was also based on the absence of the enzyme activity from cultured fibroblasts. The diagnosis was confirmed on autopsy at 16 months by typical histology, electron microscopy and biochemistry of the organs. beta-galactosidase deficiency has been demonstrated in various clinical conditions ranging from generalized gangliosidosis with severe mental retardation to clinical pictures resembling Morquio's disease and normal intelligence. The heterogeneity of the clinical manifestations in beta-galactosidase deficiency could be explained by different residual activities of a structurally mutated enzyme towards its various substrates.

Ultrastructure of the guinea pig pancreas in acute hypercalcemia.

The effect of acute hypercalcemia on pancreatic ultrastructure and the ultrastructural localization of calcium during hypercalcemia were studied in the guinea pig pancreas. After 3 h of i.v. calcium infusion (0.6 mmol/kg/h), hypertrophy and distention of the Golgi apparatus and an increased number of condensing vacuoles were seen. At 6 h, vacuolar fusion and displacement of zymogen granules occurred. At 9 h, irregular distribution of zymogen granules, indentation of the nucleus with chromatin clumping, and inclusion of intact cell organelles were present. Disruption of the plasma membrane and release of cell organelles into the interstitial space were seen. Control animals receiving saline solution (0.9% NaCl) revealed normal pancreatic ultrastructure. The serum ionized calcium values were 0.65 +/- 0.36 mM in controls and 0.71 +/- 0.14, 0.79 +/- 0.21, and 1.22 +/- 0.50 mM at 3, 6, and 9 h of calcium infusion, respectively. The ultrastructural localization of calcium was performed with the pyroantimonate staining technique after 3 h of calcium and saline infusion. Large calcium deposits were found in calcium-treated animals along the plasma membrane and in the Golgi region. The findings indicate that calcium exerts a strong stimulatory effect that eventually leads to the degeneration of the pancreatic acinar cell.

Pathogenesis of osteochondrosis juvenilis Scheuermann.

In osteochondrosis juvenilis Scheuermann, foci of various sizes in the cartilaginous end plates of the vertebral bodies display a loosening or complete interruption of the collagen fibers. These findings, together with an alteration and occasional absence of the growth zone, may result in the typical deformation of the vertebral bodies. Electron micrographs of the areas with optically absent collagen fibers reveal collagen fibrils. They are arranged in an irregular pattern. We conclude that a disturbance of collagen or ground substance biosynthesis is of importance in the pathogenesis of juvenile osteochondrosis.

Infantile phytanic acid storage disease, a disorder of peroxisome biogenesis: a case report.

The infantile and classic forms of phytanic acid storage disease belong to the newly recognized group of peroxisomal disorders. In this paper we report the full clinical, morphological and biochemical results in a patient with infantile phytanic acid storage disease. The results indicate a generalized loss of peroxisomal functions due to a deficiency of peroxisomes as demonstrated in hepatocytes and cultured skin fibroblasts.

Hypercalcemic-type of small cell carcinoma of the ovary: characterization of a new tumor line.

BACKGROUND: The aim of this study was to develop and characterize a mouse xenograft model for the hypercalcemic-type of small cell carcinoma of the ovary (HTSCCO). PATIENTS AND METHODS: Tumor fragments were removed from a patient and cultured in six subsequent generations of nude mice. Histology, comparative genomic hybridization (CGH), electron microscopy and serum calcium levels were investigated. RESULTS: Morphology remained the same from the primary tumor of the patient through the 6th passage in the mouse. Serum calcium levels were significantly higher in the tumor-bearing mice compared to controls. CGH of the HTSCCO did not show evidence of a close relationship to either a germ cell tumor or an epithelial ovarian cancer. CONCLUSION: Some evidence was provided that the HTSCCO is an inhomogeneous tumor that is neither related to a germ cell tumor nor to an epithelial ovarian cancer, but is a distinct tumor entity.