Azathioprine is effective for oral involvement in Crohn's disease but not for orofacial granulomatosis alone.

BACKGROUND: There have been no previous reports assessing the effectiveness of azathioprine (AZA) in the treatment of orofacial granulomatosis (OFG). This report is a review of patients receiving AZA for active OFG with or without concomitant gut Crohn's disease (CD) in a specialist tertiary referral centre. METHODS: Clinical response was defined by Global Physician Assessment at 4-, 12- and 24-month follow-up and a standardised oral disease activity score (ODAS). RESULTS: Sixty of 215 patients seen with OFG in our clinic over a 12-year period were treated with AZA. Of these, 22 had concomitant CD. The proportion of patients responding to AZA with a diagnosis of CD/OFG vs. OFG only at 4, 12 and 24 months were 54% vs. 21% (P = 0.03), 59% vs. 21% (P = 0.003) and 41% vs. 24% (P = 0.16), respectively. A statistically significant difference was seen between starting and follow-up ODAS scores at 4 months in the CD/OFG group which was not observed in the OFG only group. Factors predicting a need for AZA included a diagnosis of intestinal CD, sulcal swelling, sulcal ulcers and upper lip involvement. The factor predicting response to treatment was a diagnosis of CD at 12 months of follow-up. No difference in the number of adverse effects was observed between the two groups of patients. CONCLUSIONS: AZA is significantly more effective in the treatment of oral disease with a concurrent diagnosis of CD rather than in the treatment of OFG alone.

Human genomics of the humoral immune response against polyomaviruses.

Human polyomaviruses are widespread in humans and can cause severe disease in immunocompromised individuals. To identify human genetic determinants of the humoral immune response against polyomaviruses, we performed genome-wide association studies and meta-analyses of qualitative and quantitative immunoglobulin G responses against BK polyomavirus (BKPyV), JC polyomavirus (JCPyV), Merkel cellpolyomavirus (MCPyV), WU polyomavirus (WUPyV), and human polyomavirus 6 (HPyV6) in 15,660 individuals of European ancestry from three independent studies. We observed significant associations for all tested viruses: JCPyV, HPyV6, and MCPyV associated with human leukocyte antigen class II variation, BKPyV and JCPyV with variants in FUT2, responsible for secretor status, MCPyV with variants in STING1, involved in interferon induction, and WUPyV with a functional variant in MUC1, previously associated with risk for gastric cancer. These results provide insights into the genetic control of a family of very prevalent human viruses, highlighting genes and pathways that play a modulating role in human humoral immunity.

An unusual case of carotid dissection.

Carotid dissection is a rare, but potentially fatal, cause of ischaemic stroke in young patients. It occurs when a small tear forms in the tunica intima of the arterial wall creating a space between the inner and outer layers of the vessel where blood can enter and form a haematoma. This can cause a stenosis or complete occlusion. Thromboembolic events are thought to be the cause of infarction in the majority of cases of stroke, rather than haemodynamic insufficiency, in patients with carotid dissection. Although traditionally thought to be most commonly caused by head or neck trauma, spontaneous carotid dissection is now an increasingly recognised cause of stroke in young patients. Clinical signs can often be subtle, with mild cerebral or cranial nerve dysfunction. Here, a case is reported of a spontaneous internal carotid artery dissection in a previously well 38-year-old man. An appropriate imaging modality is important to confirm the diagnosis before commencing anticoagulation treatment.

Ocular melanosis in the Cairn Terrier: histopathological description of the condition, and immunohistological and ultrastructural characterization of the characteristic pigment-laden cells.

OBJECTIVE: To describe the microscopic features and lineage of proliferating/infiltrating pigmented cells in ocular melanosis of Cairn Terriers. Animals studied Forty-nine globes removed from 45 Cairn Terriers with ocular melanosis and three globes from control dogs were available for microscopic examination. PROCEDURES: All globes were examined histologically, eight affected and three control globes were also examined by immunohistochemistry, and three affected and three control globes by transmission electron microscopy. RESULTS: Large round pigment-laden cells infiltrated the anterior uvea, obscured the drainage angle and were present within the sclera and episclera of affected globes. Similar pigmented cells were present in lower numbers in the posterior segment of the globe, the optic nerve meninges and periphery of the optic nerve. Changes due to chronic glaucoma were present in many globes and some had evidence of uveitis. Many of the pigmented cells were immunoreactive to HMB45 and some were MITF and vimentin positive. One globe, which was inflamed when removed, had many pigmented cells that were CD18 immunoreactive. The other eyes had lower numbers of CD18 positive cells. The pigmented cells were not immunoreactive to smooth muscle actin, S-100, MART/Melan A, chromogranin A/B, PGP 9.5, synaptophysin, MNF116, AE1/AE3, and CD45. Ultrastructurally many of the pigmented cells had features typical of melanocytes while a smaller number appeared to be melanophages. CONCLUSIONS: Ocular melanosis in Cairn Terriers is characterized by an infiltration of pigment-laden cells predominantly, but not exclusively, within the anterior uvea and anterior sclera. Most of these cells appear to be melanocytes although a variable proportion are pigment-laden melanophages.

Assessment of the dark-adaptation time required for recovery of electroretinographic responses in dogs after fundus photography and indirect ophthalmoscopy.

OBJECTIVE: To investigate the duration of dark-adaptation time required for recovery of electroretinographic responses after fundus photography or indirect ophthalmoscopy in dogs. ANIMALS: 6 dogs. PROCEDURE: Initially, scotopic-intensity series of electroretinograms (ERGs) were recorded after 20 minutes of dark adaptation. The fundus of the left eye of each dog was photographed (n = 10) or examined via indirect ophthalmoscopy for 5 minutes with moderate- (117 candela [cd]/m2) or bright-intensity (1,693 cd/m2) light; ERGs were repeated after a further 20 or 60 minutes of dark adaptation (6 procedures/dog). RESULTS: Following 20 minutes of dark adaptation after fundus photography, the b- and a-wave amplitudes were reduced in response to brighter stimuli, compared with pretest ERGs; after 60 minutes of dark adaptation, ERG amplitudes had recovered. Following 20 minutes of dark adaptation after indirect ophthalmoscopy (moderate-intensity light), significantly lower b-wave amplitudes were recorded in response to 2 of the brighter flash stimuli, compared with pretest ERGs; after 60 minutes of dark adaptation, ERG amplitudes had recovered. Following 20 minutes of dark adaptation after indirect ophthalmoscopy (bright-intensity light), all ERG amplitudes were significantly decreased and implicit times were significantly decreased at several flash intensities, compared with pretest ERGs; after 60 minutes of dark adaptation, ERG amplitudes and implicit times had returned to initial values, except for b-wave amplitudes recorded in response to dimmer stimuli. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that at least 60 minutes of dark adaptation should be allowed before ERGs are performed in dogs after fundus photography or indirect ophthalmoscopy.

Corneal collagen fibrils: dissection with specific collagenases and monoclonal antibodies.

To investigate the relationship of collagen types I and V within corneal fibrils, and the collagenolytic mechanisms potentially involved in corneal development and remodeling, we have incubated cryostat sections of avian corneas with collagenases that specifically degrade collagen types I or V to digest selectively the collagen in situ. These preparations were then analyzed by immunofluorescence histochemistry and immunoelectron microscopy using anti-collagen type-specific monoclonal antibodies. Digestion of corneal sections with the type I-specific collagenase ("I'ase") exposed antigenically masked type V collagen, indicating that epitopes on type V collagen in heterotypic fibrils are inaccessible to the antibody due to their interaction with type I collagen. Sections digested with the type V collagen-degrading enzyme ("V'ase") showed no removal of type V collagen. However, after the fibrillar structure was disrupted by acetic acid treatment before enzyme digestion, the type V collagen was then degraded. Likewise, prior digestion of type I collagen by I'ase also rendered type V collagen susceptible to digestion by V'ase. These results suggest that the cleavage sites on type V collagen also are buried within heterotypic fibrils and therefore inaccessible to the enzyme. They also document, for the first time, V'ase activity against type V collagen in situ. Electron microscopic observations of sections partially digested with the I'ase revealed many short striated fibrillar segments from which smaller filaments protrude. Both the striated regions and some of the filaments were labeled by an antibody against type I collagen; anti-type V antibody reacted preferentially with the thin filaments. Thus avian corneal fibrils contain type I collagen, in which filaments of type V collagen are embedded. Complete removal of the fibrillar stromal matrix in the course of normal or pathological remodeling requires at least two different collagenases acting in concert.

Ocular melanosis in the Cairn Terrier: clinical description and investigation of mode of inheritance.

OBJECTIVE: To describe the clinical features of ocular melanosis in Cairn Terriers. ANIMAL STUDIED: One hundred and fourteen Cairn Terriers diagnosed with ocular melanosis. PROCEDURES: A complete eye examination was performed on each dog. Four dogs (and two unaffected control dogs) underwent a high frequency ultrasound examination of the anterior segment. The pedigrees of affected dogs were analyzed. RESULTS: Forty-four (38.6%) dogs were male and 67 (58.7%) female; the sex of three dogs (2.6%) was not provided. A four-stage grading system of the ocular changes was developed. There was a variable age of onset, and the earliest change was a dark-colored thickening of the iris root. This was followed by the development of episcleral/scleral pigment plaques, release of pigment into the aqueous and deposition in the drainage apparatus, particularly ventrally. Secondary glaucoma developed in the most severely affected dogs. A slow progression of pigmentation in the tapetal fundus was observed and in some dogs pigment on the surface of the optic nerve head was seen. Three dogs developed uveal melanocytic neoplasms. Pedigree analysis suggested a possible autosomal dominant mode of inheritance. CONCLUSIONS: Ocular melanosis is an inherited, probably autosomal-dominant condition with a variable age of onset and rate of progression. It results in a thickening and pigmentation of the iris, release of pigmented material into the aqueous, pigment deposition in the sclera/episclera, and to a lesser extent posterior segment pigment deposition. Following extensive pigment deposition in the aqueous drainage pathways it can result in secondary glaucoma.

Acquisition of type IX collagen by the developing avian primary corneal stroma and vitreous.

Previous investigations from our laboratory and others have demonstrated that type II collagen, once thought to be a cartilage-specific molecule, is also a component of both the primary corneal stroma and the vitreous of embryonic chickens. In the present immunohistochemical study we have examined the expression in these embryonic matrices of another "cartilage-specific" collagen, type IX, along with type II. In the cornea, type IX collagen is in the primary stroma, but is not detectable in the mature, secondary stroma. Even within the primary stroma this collagen has a brief, transitory existence. It first appears in the peripheral stroma at the time the endothelial cells begin to migrate along its posterior surface, and spreads throughout the stroma during the following 24-36 hr. The epitopes on type IX collagen then suddenly become undetectable just before this matrix swells and becomes populated by the periocular mesenchymal cells (future keratocytes). In comparison, collagen type II (along with type I) is present in the stroma before and long after these events. Deposition of immunodetectable type IX collagen in the developing corneal stroma thus seems to be independent of type II. In the vitreous, we observed type IX collagen along with type II as soon as authentic vitreous could be identified and at all subsequent stages of development. In this tissue, therefore, the expression of collagen types IX and II appears to be coordinate.

Type VI collagen: immunohistochemical identification as a filamentous component of the extracellular matrix of the developing avian corneal stroma.

Selected stages of the developing chicken cornea have been examined for type VI collagen, employing monoclonal antibodies specific for this molecule. By immunofluorescence, the molecule is not detectable in 5 1/2 day corneas, a time at which the epithelial-derived, acellular primary stroma is the only corneal matrix present. One day later, the presumptive stromal fibroblasts have invaded this stroma and have initiated synthesis of the secondary (mature) stroma. By that time, a strong fluorescent signal for the type VI collagen molecule is detectable throughout the stroma. It is present in all subsequent ages examined. The molecule is not restricted to the cornea, and is present in most stromal matrices examined, including those of the sclera, eyelid, and nictitating membrane. Immunoelectron microscopy was also performed, utilizing a colloidal gold-labeled secondary antibody. These data show that the type VI collagen is not a component of the striated collagen fibrils, but instead is assembled in the form of thin filaments. The monoclonal antibody bound to the filaments at periodic intervals of about 100 nm.

Independent deposition of collagen types II and IX at epithelial-mesenchymal interfaces.

Previous studies have demonstrated the presence of type II collagen (in mature chickens predominantly a 'cartilage-specific' collagen) in a variety of embryonic extracellular matrices that separate epithelia from mesenchyme. In an immunohistochemical study using collagen type-specific monoclonal antibodies, we asked whether type IX collagen, another 'cartilage-specific' collagen, is coexpressed along with type II at such interfaces. We confirmed that, in the matrix underlying a variety of cranial ectodermal derivatives and along the ventrolateral surfaces of neuroepithelia, type II collagen is codistributed with collagen types I and IV. Type IX collagen, however, was undetectable at those sites. We observed immunoreactivity for type IX collagen only within the notochordal sheath, where it first appeared at a later stage than did collagen types I and II. We also observed type II collagen (without type IX) beneath the dorsolateral ectoderm at stage 16; this correlates with the period during which limb ectoderm has been reported to induce the mesoderm to become chondrogenic. Finally, in older hind limbs we observed subepithelial type II collagen that was not associated with subsequent chondrogenesis, but appeared to parallel the formation of feathers and scales in the developing limb. These observations suggest that the deposition of collagen types II and IX into interfacial matrices is regulated independently, and that induction of mesenchymal chondrogenesis by such matrices does not involve type IX collagen. Subepithelial type IX collagen deposition, on the other hand, correlates with the assembly of a thick multilaminar fibrillar matrix, as present in the notochordal sheath and, as shown previously, in the corneal primary stroma.

Avian type VI collagen. Monoclonal antibody production and immunohistochemical identification as a major connective tissue component of cornea and skeletal muscle.

Two monoclonal antibodies have been characterized as being against avian type VI collagen. By competition ELISA, the antibodies bound to the native type VI collagen molecule but not to its separated chains or to any of the other native collagen types tested. By rotary shadowing analysis of complexes of antibody-type VI collagen monomers, one of the antibodies (VI-EC6) has been shown to bind to a site in the triple helical domain of the molecule. The site at which this antibody binds to the dimeric form of type VI collagen is consistent with the previously proposed model for a supramolecular organization of the molecule (Furthmayr et al., Biochem j 211 (1983) 303) in which the monomers are arranged in an antiparallel, slightly staggered overlap. Immunofluorescence analyses of sections of chicken eyes and skeletal muscle demonstrate that type VI collagen is a major component of most stromal matrices.

Bovine immunodeficiency virus tat gene: cloning of two distinct cDNAs and identification, characterization, and immunolocalization of the tat gene products.

cDNAs encoding the bovine immunodeficiency virus (BIV) transactivator gene (tat) were cloned from virally infected cells and characterized. BIV expresses two distinct tat mRNAs composed of three exons that are derived by alternative splicing. The BIV tat mRNA splice variants encode Tat proteins of 103 (Tat103) and 108 (Tat108) amino acids. The Tat103 coding region is specified only by exon 2, while that of Tat108 is specified by a truncated exon 2 and the first 30 nt of exon 3. Thus, the first 98 amino acids of each Tat are identical, and have amino terminal, cysteine-rich, conserved core, basic, and carboxyl-terminal domains similar to Tats encoded by primate lentiviruses. BIV-infected bovine cells express a 14-kDa phosphorylated Tat protein identical in size to recombinant Tat expressed in bacteria. BIV Tat was shown to localize exclusively in the nucleoli of virally infected and Tat-expressing cells. Reporter gene assays indicated that Tat103 and Tat108 can strongly transactivate the BIV long terminal repeat (LTR) in virally permissive canine Cf2Th and nonpermissive HeLa and mouse NIH 3T3 cells, but not in permissive lapine EREp cells. However, an intact BIV tat gene is required for viral replication in both Cf2Th and EREp cells. Strong LTR activation by BIV Tat requires a TAR (transactivation responsive) element delimited by viral nt +1 to +31 and the Tat basic domain. BIV Tat strongly cross-transactivates the HIV-1 LTR in a TAR-dependent manner in Cf2Th, but not in EREp, HeLa, or NIH 3T3 cells. In contrast, strong, TAR-dependent cross-transactivation of the BIV LTR by HIV-1 Tat could not be demonstrated in any of these cell types. In Cf2Th cells Tat108 effects a moderately stronger transactivation of the BIV LTR than Tat103, indicative of a functional difference in BIV Tat proteins encoded by the mRNA splice variants. The present studies demonstrate that BIV Tat parallels the primate lentiviral Tats in structure and biochemistry but is not interchangeable with the latter.