Siberian cats help in solving part of the mystery surrounding golden cats

Golden cats have been appreciated since the beginning of the cat fancy. Golden is a modification of the tabby coat. In the Siberian breed, a specific golden phenotype, named sunshine, has been described. Sunshine tabby cats exhibit a warm tone of tabby, a pink nose lacking the black lining and a large light cream area around the nose. Pedigree analyses revealed an autosomal recessive inheritance pattern. A single candidate region was identified by genome-wide association study (GWAS) and homozygosity mapping. Within that region, we identified CORIN (Corin, serine peptidase) as a strong candidate gene, since CORIN variants have been identified in mice and tigers with a golden phenotype and CORIN has been described as a modifier of the ASIP (Agouti Signaling Protein) pathway. A homozygous CORIN:c.2383C>T missense variant was identified in sunshine tabby cats. Segregation of the variant was consistent with recessive inheritance. The variant was also found in three Kurilian bobtail cats and in two ToyBob cats from the 99 Lives dataset but genotyping of 106 cats from 13 breeds failed to identify carriers in cats from other breeds. The CORIN:c.2383C>T variant was predicted to change an arginine to a cysteine at position 795 in the protein: CORIN:p.(Arg795Cys). Finally, hair observation in Siberian cats was consistent with elongated ASIP signaling as golden hair showed a large yellow band instead of the short subapical one usually observed in agouti hair. These results support an association of the Siberian sunshine modification with the CORIN:c.2383C>T variant. The Siberian cat has helped us to decipher one of the golden phenotypes observed in cats and we propose that the CORIN:c.2383C>T variant represents the wb^SIB (Siberian recessive wideband) allele in the domestic cat.

The retinal pigment epithelium undergoes massive apoptosis during early differentiation and pigmentation of the optic cup

PURPOSE

The aim of our work was to study apoptosis during the development of the retinal pigment epithelium (RPE) in mice between embryonic day (E) 10.5 and E12.5 and to examine a possible link between apoptosis and pigmentation.

METHODS

We collected mouse embryos at E10.5, E11.5, and E12.5 and labeled apoptotic cells in 5-µm paraffin sections, using the terminal deoxynucleotidyl transferase dUTP nick end labeling technique. We counted the total number of cells and the number of apoptotic cells in the early developing RPE and calculated the percentage of apoptosis at each stage.

RESULTS

In the C57BL/6J mouse, 17% of the RPE cells were apoptotic at E10.5 compared to 0.9% at E12.5. At E11.5, three-quarters of the RPE cells began to pigment, and apoptotic cells were located mostly in the nonpigmented part. In contrast, in the BALB/c mouse (tyrosinase-deficient) and pJ mouse (carrying mutations in the p gene) hypopigmented strains, the RPE contained significantly fewer apoptotic cells (7.5% and 10.1%, respectively) at E10.5 than controls. Subsequently at E11.5 and E12.5, the two hypopigmented strains displayed different apoptotic patterns; the BALB/c RPE had a similar percentage of apoptotic cells to controls (1.5% and 1.1%, respectively, for BALB/c versus 3.0% and 0.9%, respectively, for C57BL/6J), whereas the pJ RPE contained significantly more apoptosis (7.5% and 3.5%, respectively). Overall we observed differences in the evolution of the relative total number of RPE cells between the three strains.

CONCLUSIONS

Apoptosis is a main event during the first stages of normal RPE development, indicating an essential role during RPE differentiation. Moreover, the early apoptotic pattern and possibly the whole early development of the RPE is different between hypopigmented and pigmented strains, as well as between BALB/c and pJ mice. This suggests the existence of regulatory and developmental differences with a more complex origin than just differing pigmentation levels.

Prospective echocardiographic and tissue Doppler imaging screening of a population of Maine Coon cats tested for the A31P mutation in the myosin-binding protein C gene: a specific analysis of the heterozygous status

BACKGROUND

A mutation in the sarcomeric gene coding for the myosin-binding protein C gene has been identified in a colony of Maine Coon cats with hypertrophic cardiomyopathy (MyBPC3-A31P mutation). However, the close correlation between genotype and phenotype (left ventricular hypertrophy [LVH] and dysfunction) has never been assessed in a large population, particularly in heterozygous (Hetero) cats.

OBJECTIVES

To investigate LV morphology and function with echocardiography and tissue Doppler imaging (TDI) in a population of Maine Coon cats tested for the MyBPC3-A31P mutation with focus on Hetero animals.

ANIMALS

Ninety-six Maine Coon cats.

METHODS

Prospective observational study. Cats were screened for the MyBPC3-A31P mutation and examined with both echocardiography and 2-dimensional color TDI.

RESULTS

Fifty-two out of 96 cats did not have the mutation (wild-type genotype, Homo WT), 38/96 and 6/96 were Hetero- and homozygous-mutated (Homo M) cats, respectively. Only 11% of Hetero cats (4/38) had LVH and 29% (10/34) of Hetero cats without LVH were >4 years old (4.1-11.5 years). LVH was also detected in 2 Homo WT cats (4%). A significantly decreased (P < .05) longitudinal E/A (ratio between early and late diastolic myocardial velocities) in the basal segment of the interventricular septum was observed in Hetero cats without LVH (n = 34) compared with Homo WT cats without LVH (n = 50), thus confirming that the Hetero status is associated with regional diastolic dysfunction (P < .05).

CONCLUSIONS

The heterozygous status is not consistently associated with LVH and major myocardial dysfunction. Moreover, Homo WT cats can also develop LVH, suggesting that other genetic causes might be implicated.

Analysis of partner of inscuteable (mPins) expression in the developing mouse eye

PURPOSE

Asymmetric cell division (ACD) is the fundamental mechanism underlying the generation of cellular diversity in invertebrates and vertebrates. During Drosophila neuroblast division, this process involves stabilization of the apical complex and interaction between the Inscuteable (Insc) and Partner of inscuteable (Pins) proteins. Both cell-intrinsic factors and cell-cell interactions seem to contribute to cell fate decisions in the retina. The Pins protein is known to play a major role in the asymmetric segregation of cell fate determinants during development of the central nervous system in general, but its role in asymmetric cell divisions and retinoblast cell fate has never been explored. The primary aim of this study was to determine the spatial distribution and time course of mouse homolog of Drosophila Partner of Inscuteable (mPins) expression in the developing and adult mouse eye.

METHODS

The expression pattern of mPins was studied in the mouse eye from embryonic (E) stage E11.5 until adulthood, by semiquantitative RT-PCR, in situ hybridization, and immunohistochemistry. In addition, variations in mRNA and protein levels for mPins were analyzed in the developing postnatal and adult lens, by semiquantitative RT-PCR, western blot analysis, in situ hybridization, and immunohistochemistry.

RESULTS

We detected mPins mRNA at early stages of mouse embryonic eye development, particularly in the neuroblastic layer. In early postnatal development, mPins mRNA was still detected in the neuroblastic layer, but also began to be detectable in the ganglion cell layer. Thereafter, mPins mRNA was found throughout the retina. This pattern was maintained in differentiated adult retina. Immunohistochemical studies showed that mPins protein was present in the neuroblastic layer and the ganglion cell layer during the early stages of postnatal retinal development. At these stages, mPins protein was colocalized with Numb protein, a marker of the ACD. At later postnatal stages, mPins protein was present in all retinal nuclear layers and in the inner plexiform layer. It continued to be detected in these layers in the differentiated retina; the outer plexiform layer and the photoreceptor inner segments also began to display positive immunostaining for mPins. In the adult retina, mPins was also detected in the retinal pigment epithelium and choroidal melanocytes. Throughout development, mPins protein was detected in nonretinal tissues, including the cornea, ciliary body, and lens. We focused our attention on lens development and showed that mPins protein was first detected at E14.5. The most striking results obtained concerned the lens, in which mPins protein distribution switched from the anterior to the posterior region of the lens during embryonic development. Interestingly, in the postnatal and adult lens, mPins protein was detected in all lens cells and fibers.

CONCLUSIONS

We provide the first demonstration that mPins protein is expressed from embryonic stages until adulthood in the mouse eye. These results suggest that mPins plays important roles in eye development. This work provides preliminary evidence strongly supporting a role for mPins in the asymmetric division of retinoblasts, and in the structure and functions of adult mouse retina. However, the link between the presence of mPins in different ocular compartments and the possible occurrence of asymmetric cell divisions in these compartments remains to be clarified. Further studies are required to elucidate the in vitro and in vivo functions of mPins in the developing and adult human eye.

Differential regulation of Dlg1, Scrib, and Lgl1 expression in a transgenic mouse model of ocular cancer

PURPOSE

Discs large (dlg), scribble (scrib), and lethal giant larvae (lgl) are major suppressor genes in Drosophila melanogaster. They encode proteins that regulate cell polarity and cell proliferation in Drosophila and mammals. However, their basic oncogenic roles have not yet been established in mouse epithelial ocular cancer. We evaluated the potential implication of these proteins in tumorigenesis of adenocarcinomas originating from the retinal pigmented epithelium of the Trp1/Tag transgenic mouse model. We examined the changes in the distribution and levels of these proteins in mouse ocular tissues from the Trp1/Tag mouse model.

METHODS

The expression patterns of theses genes and their corresponding proteins in normal mouse ocular tissues were studied by in situ hibridization and immunohistofluorescence experiments. In addition, variations in mRNA and proteins levels and protein distributions for Dlg1, Scrib, and Lgl1 were analyzed in the ocular tissues from Trp1/Tag transgenic mouse model by reverse transcription polymerase chain reaction (RT-PCR), western blot analysis, and immunohistofluorescence.

RESULTS

We found that mouse Dlg1, Scrib, and Lgl1 are widely distributed in normal ocular tissues, particularly in retinal neurons. We found that the three proteins are mislocalized in retinal layers during ocular carcinogenesis. These mislocalizations were correlated to the early dysplastic stages of ocular tumorigenesis. Additionally, the mislocalization of each protein was associated with its downregulation. Decreased levels of these proteins may be considered as late-stage markers of the disease but also as markers of the invasive stage of this cancerous process. This downregulation may be involved in epithelial-mesenchymal transition in this mouse ocular tumoral model. This would be consistent with the downregulation of E-cadherin and upregulation of N-cadherin expression observed in this model.

CONCLUSIONS

This is the first study to demonstrate the involvement of Dlg1, Scrib, and Lgl1 in a mouse with ocular adenocarcinoma and the simultaneous involvement of these proteins in the same cancer. Our results indicate that both the mislocalization and downregulation of these proteins may be involved together in ocular carcinogenesis.

The RNA-binding protein Musashi-1 is produced in the developing and adult mouse eye

PURPOSE

Musashi-1 (Msi1) is an RNA-binding protein produced in various types of stem cells including neural stem/progenitor cells and astroglial progenitor cells in the vertebrate central nervous system. Other RNA-binding proteins such as Pumilio-1, Pumilio-2, Staufen-1, and Staufen-2 have been characterized as potential markers of several types of stem or progenitor cells. We investigated the involvement of Msi1 in mouse eye development and adult mouse eye functions by analyzing the profile of Msi1 production in all ocular structures during development and adulthood.

METHODS

We studied Msi1 production by in situ hybridization and immunohistochemistry of ocular tissue sections and by semi-quantitative RT-PCR and western blot analysis from the embryonic stage of 12.5 days post coitum (E12.5 dpc) when the first retinal ganglion cells (RGCs) begin to appear to the adult stage when all retinal cell types are present.

RESULTS

Msi1 mRNA was present at all studied stages of eye development. Msi1 protein was detected in the primitive neuroblastic layer (NbL), the ganglion cell layer (GCL), and in all major differentiated neurons of postnatal developing and adult retinae. During postnatal developing stages, faint diffuse Msi1 protein staining is converted to a more specific distribution once mouse retina is fully differentiated. The most striking result of our study concerns the large amounts of Msi1 protein and mRNA in several unexpected sites of adult mouse eyes including the corneal epithelium and endothelium, stromal keratocytes, progenitor cells of the limbus, equatorial lens stem cells, differentiated lens epithelial cells, and differentiating lens fibers. Msi1 was also found in the pigmented and nonpigmented cells of the ciliary processes, the melanocytes of the ciliary body, the retinal pigment epithelium, differentiated retinal neurons, and most probably in the retinal glial cells such as Müller glial cells, astrocytes, and the oligodendocytes surrounding the axons of the optic nerve. Msi1 expression was detected in the outer plexiform layer, the inner plexiform layer, and the nerve fiber layer of fully differentiated adult retina.

CONCLUSIONS

We provide here the first demonstration that the RNA-binding protein, Msi1, is produced in mouse eyes from embryonic stages until adulthood. The relationship between the presence of Msi1 in developing ocular compartments and the possible stem/progenitor cell characteristics of these compartments remains unclear. Finally, the expression of Msi1 in several different cell types in the adult eye is extremely intriguing and should lead to further attempts to unravel the role of Msi1 in cellular and subcellular RNA metabolism and in the control of translational processes in adult eye cells particularly in adult neuronal dendrites, axons, and synapses.

Ursodesoxycholic acid and heme-arginate are unable to improve hematopoiesis and liver injury in an erythropoietic protoporphyria mouse model

Erythropoietic protoporphyria (EPP) is an inherited disorder of heme biosynthesis caused by partial ferrochelatase deficiency, resulting in protoporphyrin overproduction which is responsible for painful skin photosensitivity. Chronic liver disease is the most severe complication of EPP, requiring liver transplantation in some patients. Data from a mouse model suggest that cytotoxic bile formation with high concentrations of bile salts and protoporphyrin may cause biliary fibrosis by damaging bile duct epithelium. In humans, cholestasis is a result of intracellular and canalicular precipitation of protoporphyrin. To limit liver damage two strategies may be considered: the first is to reduce protoporphyrin production and the second is to enhance protoporphyrin excretion. Bile salts are known to increase protoporphyrin excretion via the bile, while heme arginate is used to decrease the production of porphyrins in acute attacks of hepatic porphyrias. The Griseofulvin-induced protoporphyria mouse model has been used to study several aspects of human protoporphyria including the effects of bile salts. However, the best EPP animal model is an ethylnitrosourea-induced point mutation with fully recessive transmission, named ferrochelatase deficiency (Fech(m1Pas)). Here we investigate the effect of early ursodesoxycholic acid (UDCA) administration and heme-arginate injections on the ferrochelatase deficient EPP mouse model. In this model UDCA administration and heme-arginate injections do not improve the protoporphyric condition of Fech(m1Pas)/Fech(m1Pas) mice.

New VMD2 gene mutations identified in patients affected by Best vitelliform macular dystrophy

PURPOSE

The mutations responsible for Best vitelliform macular dystrophy (BVMD) are found in a gene called VMD2. The VMD2 gene encodes a transmembrane protein named bestrophin-1 (hBest1) which is a Ca(2+)-sensitive chloride channel. This study was performed to identify disease-specific mutations in 27 patients with BVMD. Because this disease is characterised by an alteration in Cl(-) channel function, patch clamp analysis was used to test the hypothesis that one of the VMD2 mutated variants causes the disease.

METHODS

Direct sequencing analysis of the 11 VMD2 exons was performed to detect new abnormal sequences. The mutant of hBest1 was expressed in HEK-293 cells and the associated Cl(-) current was examined using whole-cell patch clamp analysis.

RESULTS

Six new VMD2 mutations were identified, located exclusively in exons four, six and eight. One of these mutations (Q293H) was particularly severe. Patch clamp analysis of human embryonic kidney cells expressing the Q293H mutant showed that this mutant channel is non-functional. Furthermore, the Q293H mutant inhibited the function of wild-type bestrophin-1 channels in a dominant negative manner.

CONCLUSIONS

This study provides further support for the idea that mutations in VMD2 are a necessary factor for Best disease. However, because variable expressivity of VMD2 was observed in a family with the Q293H mutation, it is also clear that a disease-linked mutation in VMD2 is not sufficient to produce BVMD. The finding that the Q293H mutant does not form functional channels in the membrane could be explained either by disruption of channel conductance or gating mechanisms or by improper trafficking of the protein to the plasma membrane.

A gene transfer comparative study of HSA-conjugated antiangiogenic factors in a transgenic mouse model of metastatic ocular cancer

Different antiangiogenic and antimetastatic recombinant adenoviruses were tested in a transgenic mouse model of metastatic ocular cancer (TRP1/SV40 Tag transgenic mice), which is a highly aggressive tumor, developed from the pigmented epithelium of the retina. These vectors, encoding amino-terminal fragments of urokinase plasminogen activator (ATF), angiostatin Kringles (K1-3), endostatin (ES) and canstatin (Can) coupled to human serum albumin (HSA) were injected to assess their metastatic and antiangiogenic activities in our model. Compared to AdCO1 control group, AdATF-HSA did not significantly reduce metastatic growth. In contrast, mice treated with AdK1-3-HSA, AdES-HSA and AdCan-HSA displayed significantly smaller metastases (1.19+/-1.19, 0.87+/-1.5, 0.43+/-0.56 vs controls 4.04+/-5.12 mm3). Moreover, a stronger inhibition of metastatic growth was obtained with AdCan-HSA than with AdK1-3-HSA (P=0.04). Median survival was improved by 4 weeks. A close correlation was observed between the effects of these viruses on metastatic growth and their capacity to inhibit tumor angiogenesis. Our study indicates that systemic antiangiogenic factors production by recombinant adenoviruses, particularly Can, might represent an effective way of delaying metastatic growth via inhibition of angiogenesis.

Major role of BAX in apoptosis during retinal development and in establishment of a functional postnatal retina

Apoptosis plays a major role in the development of the central nervous system. Previous studies of apoptosis induction during retinal development are difficult to interpret, however, because they explored different mouse strains, different developmental periods, and used different assays. Here, we first established a comprehensive sequential pattern of cell death during the whole development of the C57BL/6J mouse retina, from E10.5 to postnatal day (P) 21 by using the terminal deoxynucleotidyl transferase (TdT) -mediated deoxyuridine triphosphate (dUTP)-biotinylated nick end labeling (TUNEL) assay. We confirmed the existence of three previously described apoptotic peaks and identified another, later peak at P15, in both the outer nuclear layer, in which the photoreceptors differentiate, and the ganglion cell layer. Comparison of wild-type C57BL/6 mice, gld mice, defective in the death ligand fasL, and bax-/- mice, defective in the pro-apoptotic BAX protein, revealed a minor role for FAS ligand but a crucial role for BAX in both apoptosis and normal retinal development. The lack of BAX resulted in thicker than normal inner neuroblastic and ganglion cell layers in adults, with larger numbers of cells and an impaired electroretinogram response related to a decreased number of responsive cells. Our findings indicate that cell death during normal retinal development is important for the modeling of a functional vision organ and showed that the pro-apoptotic BAX protein plays a crucial role in this process.

Prominent beta-5 gene expression in the cardiovascular system and in the cartilaginous primordiae of the skeleton during mouse development

The alpha v beta (alpha(v)beta5) heterodimer has been implicated in many biological functions, including angiogenesis. We report the beta5 gene expression pattern in embryonic and foetal mouse tissues as determined by Northern blotting and in situ hybridization. During the earliest stages, beta5 mRNA is widespread in the mesoderm. During later developmental stages, it remains mostly confined to tissues of mesodermal origin, although probable inductive effects trigger shifts of beta5 gene expression from some mesenchymatous to epithelial structures. This was observed in the teeth, skin, kidneys, and gut. Of physiological importance is the beta5 labeling in the developing cardiovascular and respiratory systems and cartilages. Furthermore, early beta5 gene expression was observed within the intra- and extraembryonic sites of hematopoiesis. This suggests a major role for beta5 in the hematopoietic and angiogenic stem cells and thus in the development of the vascular system. Later, the beta5 gene was expressed in endothelial cells of the vessels developing both by angiogenesis and vasculogenesis in the lung, heart, and kidneys. Moreover, the beta5 hybridization signal was detected in developing cartilages but not in ossified or ossifying bones. beta5-Integrin is a key integrin involved in angiogenesis, vasculogenesis, hematopoiesis, and bone formation.

In vivo adenovirus-mediated delivery of a uPA/uPAR antagonist reduces retinal neovascularization in a mouse model of retinopathy

Diabetic retinopathy and retinopathy of prematurity are among the leading causes of vision impairment throughout the world. Both diseases are characterized by pathological angiogenesis, which severely impairs vision. Extracellular proteinases play important roles in endothelial cell migration during angiogenesis. Amino-terminal fragment (ATF) is an angiostatic molecule that targets the uPA/uPAR system and inhibits endothelial cell migration. The angiostatic effect of ATF has been demonstrated in models of cancer, but has never been assessed in pathological retinal neovascularization. Endostatin also has angiostatic effects on tumor growth and retinal neovascularization. We used an adenoviral vector carrying the murine ATF (AdATFHSA) or endostatin gene coupled to human serum albumin (HSA) (AdEndoHSA) to increase the half-life of the therapeutic protein in the circulation. We induced retinopathy by exposing 7-day-old mice to high levels of oxygen. They were intravitreally injected with the vectors. Local injection of AdATFHSA or AdEndoHSA reduced retinal neovascularization by 78.1 and 79.2%, respectively. Thus, the adenovirus-mediated delivery of ATFHSA or EndoHSA reduces retinal neovascularization in a mouse model of hypoxia-induced neovascularization.

[Carcinoid tumor of the small bowel: value of hydro-MR imaging for diagnosis]

Hydro-MR imaging is a technique based on the use of a strongly T2-weighted single-shot fast spin-echo (SSFSE) sequence, similar to that used for MR-cholangiography. We report herein one case of carcinoid tumor of the small bowel diagnosed by hydro-MR imaging. This non invasive MR technique showed suggestive features such as radial convergence and segmental dilatation of a small bowel loop, similar to those seen on conventional follow-through studies. This case illustrates the major role that may be played in the future by hydro-MR imaging for the non invasive diagnosis of carcinoid tumor of the small bowel without the use of ionizing radiation.

Gamma-D crystallin gene (CRYGD) mutation causes autosomal dominant congenital cerulean cataracts

Congenital cataracts are a major cause of bilateral visual impairment in childhood. We mapped the gene responsible for autosomal congenital cerulean cataracts to chromosome 2q33-35 in a four generation family of Moroccan descent. The maximum lod score (7.19 at recombination fraction theta=0) was obtained for marker D2S2208 near the gamma-crystallin gene (CRYG) cluster. Sequencing of the coding regions of the CRYGA, B, C, and D genes showed the presence of a heterozygous C>A transversion in exon 2 of CRYGD that is associated with cataracts in this family. This mutation resulted in a proline to threonine substitution at amino acid 23 of the protein in the first of the four Greek key motifs that characterise this protein. We show that although the x ray crystallography modelling does not indicate any change of the backbone conformation, the mutation affects a region of the Greek key motif that is important for determining the topology of this protein fold. Our data suggest strongly that the proline to threonine substitution may alter the protein folding or decrease the thermodynamic stability or solubility of the protein. Furthermore, this is the first report of a mutation in this gene resulting in autosomal dominant congenital cerulean cataracts.

[Splenic rupture following colonoscopy: report of an unusual case in the absence of underlying splenic disease]

Splenic injury following colonoscopy is rare and, to our knowledge, 18 cases only have been reported so far in the literature. The presumed mechanisms for splenic injury during colonoscopy are direct trauma to the spleen or excessive traction of the splenocolic ligament this latter mechanism being due to decreased mobility between the spleen and the colon secondary to adhesions. Splenomegaly or underlying splenic disease are two conditions which are considered to be predisposing factors to splenic injury. We report one case of splenic rupture which was due to colonoscopy in the absence of any underlying splenic disease. This case was diagnosed and monitored by computed tomography, thus avoiding unnecessary splenectomy.

Systemic administration of a recombinant adenovirus encoding a HSA-Angiostatin kringle 1-3 conjugate inhibits MDA-MB-231 tumor growth and metastasis in a transgenic model of spontaneous eye cancer

We previously reported that intratumoral injection of AdK3, a recombinant adenovirus encoding human angiostatin kringle (K) 1 to 3, inhibits tumor vascularization and tumor growth. To reduce the serum clearance of this factor, we constructed an adenovirus (AdK3-HSA) that carries a chimeric gene encoding a fusion protein between angiostatin K1-3 and human serum albumin (HSA). This conjugate inhibited endothelial cell proliferation as efficiently as K1-3. K3-HSA serum concentrations in immunodeficient mice systemically injected with AdK3-HSA were dramatically higher than in AdK3-injected mice. Furthermore, the growth of MDA-MB-231 tumors grafted into nude mice that had been injected intravenously with AdK3-HSA was inhibited by 79% (versus 17% with AdK3). In TRP-1/SV40 Tag transgenic mice, which spontaneously develop eye tumors with brain metastases, intravenous injections of AdK3-HSA in newborn mice blocked metastatic dissemination efficiently and significantly, and prolonged survival by 3 weeks. After 2 months, only 46% of AdK3-HSA-treated animals developed micrometastases, whereas 94% of the AdCO1-injected group displayed numerous macrometastases. Nevertheless, ocular tumor growth was not modified because of impaired diffusion of the conjugate in the eye compartment. Our results show that HSA genetic coupling is an efficient way to increase the pharmacokinetics of circulating angiogenic inhibitors and thus their antitumoral activity.

Use of denaturing HPLC and automated sequencing to screen the VMD2 gene for mutations associated with Best's vitelliform macular dystrophy

We identified three novel VMD2 mutations in patients with Best's macular dystrophy. DHPLC analysis of the 11 VMD2 exons revealed abnormal profiles in exon 8. Direct sequencing showed that these abnormal profiles were due to monoallelic transitions and transversions. We also found three polymorphic sequence changes that have been reported previously and annotated to an online database (http://www.uni-wuerzburg.de/humangenetics/vmd2.html).

[Imaging of primary carcinoid tumor of the pancreas]

PURPOSE

To describe the imaging features of primary carcinoid tumors of the pancreas. Materials and Methods. The sonographic and computed tomographic examinations of six patients with pathologically proven primary carcinoid tumor of the pancreas were retrospectively reviewed.

RESULTS

In all cases, sonography showed hypoechoic and well circumscribed tumors. CT scan demonstrated hypoattenuating tumors on noncontrast images, with variable enhancement on postcontrast images. Small tumors (less than 2cm in diameter) were homogeneous whereas larger tumors were heterogeneous with areas of cystic necrosis. In two cases, enlarged lymph nodes were found in association with ascitis. In one case, hepatic metastases were present.

CONCLUSION

Primary carcinoid tumors of the pancreas display various and non specific imaging features. Small tumors are likely to be homogeneous and hypervascular whereas larger tumors are heterogeneous and hypovascular.

New splicing-site mutations in the SURF1 gene in Leigh syndrome patients

The gene SURF1 encodes a factor involved in the biogenesis of cytochrome c oxidase, the last complex in the respiratory chain. Mutations of the SURF1 gene result in Leigh syndrome and severe cytochrome c oxidase deficiency. Analysis of seven unrelated patients with cytochrome c oxidase deficiency and typical Leigh syndrome revealed different SURF1 mutations in four of them. Only these four cases had associated demyelinating neuropathy. Three mutations were novel splicing-site mutations that lead to the excision of exon 6. Two different novel heterozygous mutations were found at the same guanine residue at the donor splice site of intron 6; one was a deletion, whereas the other was a transition [588+1G>A]. The third novel splicing-site mutation was a homozygous [516-2_516-1delAG] in intron 5. One patient only had a homozygous polymorphism in the middle of the intron 8 [835+25C>T]. Western blot analysis showed that Surf1 protein was absent in all four patients harboring mutations. Our studies confirm that the SURF1 gene is an important nuclear gene involved in the cytochrome c oxidase deficiency. We also show that Surf1 protein is not implicated in the assembly of other respiratory chain complexes or the pyruvate dehydrogenase complex.

Mutations in the SURF1 gene associated with Leigh syndrome and cytochrome C oxidase deficiency

Cytochrome c oxidase (COX) deficiency is one of the major causes of Leigh Syndrome (LS), a fatal encephalopathy of infancy or childhood, characterized by symmetrical lesions in the basal ganglia and brainstem. Mutations in the nuclear genes encoding COX subunits have not been found in patients with LS and COX deficiency, but mutations have been identified in SURF1. SURF1 encodes a factor involved in COX biogenesis. To date, 30 different mutations have been reported in 40 unrelated patients. We aim to provide an overview of all known mutations in SURF1, and to propose a common nomenclature. Twelve of the mutations were insertion/deletion mutations in exons 1, 4, 6, 8, and 9; 10 were missense/nonsense mutations in exons 2, 4, 5, 7, and 8; and eight were detected at splicing sites in introns 3 to 7. The most frequent mutation was 312_321del 311_312insAT which was found in 12 patients out of 40. Twenty mutations have been described only once. We also list all polymorphisms discovered to date.

Mutation analysis of the tyrosinase gene in oculocutaneous albinism

Type I oculocutaneous albinism (OCA) is an autosomal recessive disorder caused by the reduction or the absence of tyrosinase (TYR) activity in melanocytes of the skin, hair and eyes. Here we report an analysis of 45 patients with OCA. We found five novel mutations in the tyrosinase gene involved in the pathogenesis of oculocutaneous albinism type IA or type IB (OCA-1A/B) in five unrelated patients. Three mutations are missense mutations (G109R, P205T and H256Y) and two are nucleotide deletions (336-337delCA and 678-680delAGG). One patient is homozygous for the previously known V275F mutation but has an extremely mild OCA phenotype and has no eye features typical of OCA. In several patients we discovered only one or even no mutation in the coding sequence of the TYR gene. Thus, this disease may also result from mutations in non coding regions of the gene or in another gene involved in the biosynthesis of melanin. Hum Mutat 17:352, 2001.

Identification of novel VMD2 gene mutations in patients with best vitelliform macular dystrophy

ABSTRACT We report five novel VMD2 mutations in Best's macular dystrophy patients (S16F, I73N, R92H, V235L, and N296S). An SSCP analysis of the VMD2 11 exons revealed electrophoretic mobility shifts exclusively in exons 2, 3, 4, 6 and 8. Direct sequencing indicated that these shifts are caused by mono-allelic transition in exons 2, 4, 6, 8 and transversion in exons 3 and 6. Five novel "silent" polymorphisms are also reported: 213T>C, 323C>A, 1514A>G, 1661C>T, and 1712T>C. Hum Mutat 17:235, 2001.

Quantitative analysis of intravitreal injections in the rat

Intravitreal injections are currently used in the rat to introduce a therapeutic factor in the eye, especially for experimental treatments of retinal degenerations. The injected volume and its location can influence the quantification of results. We have investigated the quantitative effect of a single intravitreal injection in rats at different ages and for different volumes. Albinos rats aged three weeks or two months received intravitreal injections of 1, 3, 5 or 10 microl China ink. Animals were sacrificed immediately after injection, eyes were enucleated, fixated, embedded in paraffin and microtomy was performed in a sagittal plane. Regularly spaced sections were analyzed to reconstruct the vitreous and injected dye volumes. The measured vitreous volume was 6.76 +/- 0.37 mm(3) in three weeks old rats and 13.36 +/- 0.64 mm(3) in two months old rats. Mean intravitreal ink volumes immediately after injection were 0.8 mm(3) for 1 ml injections, 2 mm( 3) for 3 ml, 2.3 to 2.6 mm(3) for 5 microl and 3.2 mm(3 ) for 10 microl. The percentage of vitreous volume involved by the injection ranged from 4.4% to 33.2%. The injected volume is limited by the large lens size of the rat. Extraocular loss of injected solution increases for higher injected volumes, with larger standard deviations. In this model, the dye tends to localize behind the lens. A 3 or 5 microl volume appears to have the best reproducibility with minimum loss of solution.

Ocular cell transfection with the human basic fibroblast growth factor gene delays photoreceptor cell degeneration in RCS rats

Based on the K8/JTS-1-mediated transfection technique, we developed an in vivo protocol for an efficient transfer of plasmid DNA to ocular cells. As determined with condensed plasmids containing reporter genes for either beta-galactosidase (pcDNA-lacZ) or enhanced green fluorescent protein (pREP-EGFP), the immortalized human retinal epithelial cells RPE D407 and human embryonic kidney 293 cells can be transfected with typical efficiencies of 11 and 19%, respectively. Unlike 293 cells, RPE D407 cells had a reduced viability on transfection with both plasmids. In vivo, subretinal injections of DNA-K8/JTS-1 complexes revealed reporter gene expression in choroidal and RPE cells of normal pink-eyed Royal College of Surgeons (RCS) rats. The validity of this transfection technique in terms of retinal cell survival in RCS rats was then examined by using pREP-hFGF2 plasmid, which encodes the human basic fibroblast growth factor isoforms (hFGF2). Subretinal injection of pREP-hFGF2-K8/JTS-1 complexes into 3-week-old dystrophic RCS rat eyes reveals a delayed photoreceptor cell degeneration 60 days postinjection. In this case, the average analyzed field points with delayed cell dystrophy represent 14 to 17% of the retinal surface as compared with 2.6 and 4% in pREP5beta and vehicle-injected eyes, respectively. Peptide-mediated in oculo transfection thus appears to be a promising technique for the treatment of retinal cell and photoreceptor degenerations.

Genomic characterization and embryonic expression of the mouse Bigh3 (Tgfbi) gene

Mutations in human BIGH3 (TGFB1), a gene identified after treatment of an adenocarcinoma cell line with TGF-beta, have been observed in patients with granular Groenouw type I, Reis-Bücklers, Thiel-Behnke, Avellino, and Lattice type I and IIIa, six autosomal dominant corneal dystrophies linked to chromosome 5q. In order to gain insight into the physiological role of this gene, we characterized the genomic structure of the mouse Bigh3 and its expression in murine embryos. The gene spans 30 kb on mouse chromosome 13 and has 17 exons. Embryonic expression of Bigh3 is observed in the mesenchyme of the first and second branchial arches as early as dpc 11.5 and is particularly strong in the mesenchyme of numerous tissues throughout all the development stages. In fetal eye, the expression is first seen at 11.5 dpc in the mesenchyme surrounding the optic stalk, extends toward the sclera and choroid by 14.3 dpc and reaches the cornea by 17.5 dpc. Because the physiological role of BIGH3/Bigh3 is still largely unknown, embryonic expression in organs like heart, vessels, and intestine may help to identify new functions which could be searched for in patients and in knock-out animal models. The characterization of the murine structure is a prerequisite for the making of such models.

Quantitative analysis of subretinal injections in the rat

BACKGROUND

Experimental therapeutic approaches to retinal degenerations often require the subretinal injection of a therapeutic agent. The injected volume and the age of the animal can influence the proportion of the retinal surface affected by the subretinal injection. We have investigated the quantitative effect of a single injection in the subretinal space.

METHODS

Normal and Royal College of Surgeons rats aged 1 week, 3 weeks or 2 months received subretinal transscleral injections of 1, 3, 5 or 10 microl China ink. After 24 h, animals were killed, injected eyes were enucleated and fixated, and the retinas flattened. An image analyzing program was used to measure the total retinal surface and the retinal surface affected by the dye.

RESULTS

The mean retinal surface affected by the injection ranged from 5.24+/-2.76 mm2 to 14.8+/-2.3 mm2, depending on animal age and injected volume. The injection affected 8.79+/-0.89 to 36.9+/-8.13% of total retinal surface. There was no statistically significant difference between normal and Royal College of Surgeons rats. Intravitreal leakage of the dye was more frequent with increasing injection volumes.

CONCLUSION

The retinal surface affected by a single subretinal injection increases with the injected volume, but this increase is not proportional. Higher volumes lead to a loss of injected solution, either in the vitreous body or through the sclerotomy. In 2-month-old rats, a 3-microl subretinal injection appears to have the best reproducibility, with 20-30% of retinal surface covered by the injected dye.

Identification of novel PAX6 mutations in two families with bilateral aniridia. Mutations in brief no. 167. Online

We report two novel PAX6 mutations in aniridia patients of two Swiss pedigrees (We, Sc) which give rise to different phenotypes. An SSCP analysis of the PAX6 14 exons reveals electrophoretic mobility shifts exclusively in exons 5 and 12 of aniridia patients. As determined by bidirectional sequencing and restriction digest analysis, these shifts are caused by mono-allelic base transitions in exon 5 (c.547C-->T; R44X; We) and intron 12 (IVS12+5G-->A; Sc). Each mutation co-segregates with the trait in the affected family with complete penetrance. The Sc mutation in the splicing donor site of intron 12 may result in either intron inclusion or exon skipping, both giving rise to a truncated PAX6 protein which may retain a residual transactivating activity. In contrast, the We genetic alteration is a loss-of-function mutation leading to a more severe phenotype than that observed in the Sc pedigree.

Fibroid-related menorrhagia: treatment with superselective embolization of the uterine arteries and midterm follow-up

PURPOSE

To prospectively evaluate the effectiveness and safety of selective embolization of the uterine arteries in the management of symptomatic uterine leiomyoma.

MATERIALS AND METHODS

Eighty consecutive women (mean age, 44.7 years) with symptomatic uterine leiomyoma, none of whom desired future pregnancy, underwent superselective embolization of the uterine arteries with polyvinyl alcohol particles. In all women, arterial embolization was performed because of persistent, fibroid-related menorrhagia after failure of hormonal therapy. Follow-up consisted of office visits at 2, 6, 12, and 24 months and of ultrasonography at 2 and 6 months after the procedure.

RESULTS

Bilateral embolization of the uterine arteries was performed in 76 women; unilateral embolization, in four women. Menorrhagia disappeared in 72 (90%) women. In five (6%) women (including three women with unilateral embolization), clinical improvement was not observed, and myomectomy was needed. In one woman with a large submucosal uterine leiomyoma, hysterectomy was needed because of septic uterine necrosis. Normal menstruation resumed in all but six women. Full-term pregnancy occurred in three women after the procedure.

CONCLUSION

Superselective arterial embolization of the uterine arteries is an effective means of controlling symptomatic uterine leiomyoma. However, the ideal embolic regimen remains to be determined.

Human-mouse differences in the embryonic expression patterns of developmental control genes and disease genes

Our understanding of early human development has been impeded by the general difficulty in obtaining suitable samples for study. As a result, and because of the extraordinarily high degree of evolutionary conservation of many developmentally important genes and developmental pathways, great reliance has been placed on extrapolation from animal models of development, principally the mouse. However, the strong evolutionary conservation of coding sequence for developmentally important genes does not necessarily mean that their expression patterns are as highly conserved. The very recent availability of human embryonic samples for gene expression studies has now permitted for the first time an assessment of the degree to which we can confidently extrapolate from studies of rodent gene expression patterns. We have found significant human-mouse differences in embryonic expression patterns for a variety of genes. We present detailed data for two illustrative examples. Wnt7a, a very highly conserved gene known to be important in early development, shows significant differences in spatial and temporal expression patterns in the developing brain (midbrain, telencephalon) of man and mice. CAPN3, the locus for LGMD2A limb girdle muscular dystrophy, and its mouse orthologue differ extensively in expression in embryonic heart, lens and smooth muscle. Our study also shows how molecular analyses, while providing explanations for the observed differences, can be important in providing insights into mammalian evolution.

First prenatal diagnosis of defects in the HsPDX1 gene encoding protein X, an additional lipoyl-containing subunit of the human pyruvate dehydrogenase complex

We have previously reported a genetic study of a neonatal lactic acidosis linked to a pyruvate dehydrogenase complex deficiency due to the absence of the protein X subunit. This rare autosomal recessive disorder is associated with specific deletions in this polypeptide which is encoded by the HsPDX1 gene, located on chromosome 11p1.3. The pathology of the patient was considered to arise from a large homozygous deletion (78del85) found at the 5' end of the HsPDX1 coding sequence. Her heterozygous mother underwent prenatal diagnosis during a subsequent pregnancy. Chorionic villus samples were used for three independent studies: (1) normal levels of the protein X component of the PDH complex were detected by immunoblotting; (2) RT-PCR analysis showed no deletion at the 5' end of the cDNA but the presence of a distinct heterozygous deletion (965del59) at its 3' end inherited from the father; (3) haplotype analysis revealed the presence of the father's mutated allele and the mother's normal allele. It was concluded that the fetus was heterozygous for this separate 3' deletion, so, it was likely to be not affected. This study permitted us to characterize more precisely the genetic abnormalities of the HsPDX1 cDNA occurring in each family's member.

Localization of mRNA for CHRNA7 in human fetal brain

The aim of this study was to determine the regional distribution in situ of the mRNA for the alpha 7 subunit of the neuronal nicotinic acetylcholine receptor in human fetal brain. We found high levels of alpha 7 gene expression in nuclei that receive sensory information, such as those of the neocortex and hippocampus, the thalamic nuclei, the reticular thalamic nucleus, the pontine nuclei and the superior olive complex. These data support a possible regulatory function for alpha 7-containing receptors in sensory processing, which may be involved in the pathological physiology of schizophrenia and autism. Early alpha 7 gene expression is also consistent with a morphogenetic role for alpha 7 receptors in central nervous system development.

Expression of FMR1, FXR1, and FXR2 genes in human prenatal tissues

We analyzed the distribution of FMR1, FXR1, FXR2 mRNA, and FMRP in whole normal human embryos and in the brains of normal and fragile X fetuses. The distributions of mRNA for the 3 genes in normal whole embryos and in the brains of normal male and female carrier fetuses were similar, with large amounts of mRNA in the nervous system and in several non-nervous system tissues. No FMR1 (mRNA and protein) was detected and no evident neuropathologic abnormalities found in the brains of male carrier fetuses, suggesting that the FMR1 product (FMRP) may have no crucial function in early stages of nervous system development. FXR1 and FXR2 mRNA had the same distribution and similar intensity in the brains of normal and pathologic fetuses (female and male carriers). The coexpression in the same tissues of FMR1, FXR1, and FXR2, associated with the normal expression of FXR1 and FXR2 and the absence of obvious neuropathological abnormalities in pathological brains, supports the notion that the FXR1 and FXR2 proteins partially compensate for FMRP function. However, the absence of significant overexpression of FXR1 and FXR2 in pathological brains suggests that these genes do not compensate for the lack of FMR1 expression. Alternatively, FMR1, FXR1, and FXR2 proteins may not have compensatory functions, but instead may regulate functions by hetero or homo oligomerization, as suggested by other studies. Thus, a dominant negative effect of abnormal multimeric protein complexes lacking FMRP (e.g. by modification of FXR1 and FXR2 protein functions) may result in the fragile X syndrome phenotype.

Angiogenesis induced in muscle by a recombinant adenovirus expressing functional isoforms of basic fibroblast growth factor

The present work studies the effects of a replication-deficient adenovirus (Ad), Ad-RSVbFGF, bearing the human basic fibroblast growth factor (bFGF) cDNA, as a potential vector for therapeutic angiogenesis of ischemic diseases. The different isoforms of the protein were expressed from the viral vector in various cell types and, although the cytoplasmic isoform does not possess a signal peptide, we observed its release from a muscle cell line. The proteins were fully functional when tested in a long-term survival assay of quiescent fibroblasts. After endothelial cell infection with Ad-RSVbFGF, we observed an 80&percnt increase in the mean length of the capillary-like tubes that differentiated in a three-dimensional model of angiogenesis. We evaluated angiogenesis directly in mice 14 days after subcutaneous injection of Matrigel plugs containing Ad-RSVbFGF. A marked neovascularization was observed in the Matrigel plugs and in the surrounding tissues. Finally, the recombinant virus was injected into the hindlimb muscles of mdx mice. A 2.5-fold increase in bFGF content of the muscle was observed 6 days after injection, without any significant variations detected in the animal sera. Immunohistological detection showed an increased number of large-caliber vessels in the treated muscles as compared with control muscles. These results demonstrate that Ad-mediated transfer of the human bFGF gene can induce angiogenesis in muscle, making this tissue a potential target for the treatment of ischemic diseases.

Intravitreous transplantation of encapsulated fibroblasts secreting the human fibroblast growth factor 2 delays photoreceptor cell degeneration in Royal College of Surgeons rats

We developed an experimental approach with genetically engineered and encapsulated mouse NIH 3T3 fibroblasts to delay the progressive degeneration of photoreceptor cells in dark-eyed Royal College of Surgeons rats. These xenogeneic fibroblasts can survive in 1. 5-mm-long microcapsules made of the biocompatible polymer AN69 for at least 90 days under in vitro and in vivo conditions because of their stable transfection with the gene for the 18-kDa form of the human basic fibroblast growth factor (hFGF-2). Furthermore, when transferred surgically into the vitreous cavity of 21-day-old Royal College of Surgeons rats, the microencapsulated hFGF-2-secreting fibroblasts provoked a local delay of photoreceptor cell degeneration, as seen at 45 days and 90 days after transplantation. This effect was limited to 2.08 mm2 (45 days) and 0.95 mm2 (90 days) of the retinal surface. In both untreated eyes and control globes with encapsulated hFGF-2-deficient fibroblasts, the rescued area (of at most 0.08 mm2) was significantly smaller at both time points. Although, in a few ocular globes, surgical trauma induced a reorganization of the retinal cytoarchitecture, neither microcapsule rejection nor hFGF-2-mediated tumor formation were detected in any treated eyes. These findings indicate that encapsulated fibroblasts secreting hFGF-2 or perhaps other agents can be applied as potential therapeutic tools to treat retinal dystrophies.