A system for tissue-specific gene targeting: transgenic mice susceptible to subgroup A avian leukosis virus-based retroviral vectors.

Avian leukosis viruses (ALVs) have been used extensively as genetic vectors in avian systems, but their utility in mammals or mammalian cell lines is compromised by inefficient viral entry. We have overcome this limitation by generating transgenic mice that express the receptor for the subgroup A ALV under the control of the chicken alpha sk-actin promoter. The skeletal muscles of these transgenic animals are susceptible to efficient infection by subgroup A ALV. Because infection is restricted to cell lineages that express the transgene, the method has utility for studies of development and oncogenesis and will provide models for tissue-specific gene therapy.     

Anovaginal and rectovaginal fistula in patients with Crohn's disease.

Between 1971 and 1991, details of 67 women with perianal Crohn's disease were recorded prospectively using the Cardiff classification. Two groups were identified according to the presence (n = 29) or absence (n = 38) of anorectal Crohn's fistula involving the vagina. Patients in both groups were of a similar age and had had Crohn's disease for a similar period before diagnosis of perianal involvement. The incidence of associated perianal lesions, superficial ulcers, cavitating ulcers, other fistulas and strictures was not significantly different between the two groups. A greater proportion of patients with anorectal-vaginal fistulation (n = 15) had distal intestinal Crohn's disease (rectal or contiguous colorectal) compared with women with no vaginal fistulation (n = 14). A range of therapies was used to manage women with perianal Crohn's disease, from local surgery to a defunctioning stoma and/or proctectomy. Only 13 of 38 women with perianal Crohn's disease but no vaginal fistula required a defunctioning stoma or proctectomy, whereas 18 of 29 with anorectal-vaginal fistulation underwent these procedures (P < 0.05). A vaginal fistula has a considerable adverse effect on the outcome of perianal Crohn's disease.     

The cytological detection of persistent cervical intraepithelial neoplasia after local ablative treatment: a comparison of sampling devices.

OBJECTIVE: To determine whether the cytological detection of persistent cervical intraepithelial neoplasia (CIN) after local ablative treatment is improved by the use of sampling devices other than the Ayre's spatula. DESIGN: A randomized controlled study. SETTING: Lothian Area Colposcopy Clinic. SUBJECTS: 856 patients who had received local therapy (CO2 laser or cold coagulation) for CIN II or III between 9 and 30 months earlier. INTERVENTION: Each patient had three consecutive cervical smears taken, one with the Ayre's spatula, one with either the Aylesbury, the Rocket or the Multispatula device, and finally one with the Cytobrush. The allocation of which spatula and the order of the first two was randomized. Each patient had a colposcopic examination immediately after the smears were taken. MAIN OUTCOME MEASURES: A comparison of the detection of histologically proven persistent CIN by the Ayre's spatula with the detection of persistent disease by alternative sampling devices. RESULTS: Of the 856 patients 130 had histologically proven persistent CIN. Another 98 had suspicious findings on colposcopy but punch biopsies reported as histologically normal. Of the remaining patients with normal colposcopy 130 were randomly selected to form a control group. The cervical smears from these 358 women were reported. Significantly fewer Ayre's samples contained endocervical cells than Aylesbury samples (47% vs 59%, difference 12%; 95% CI 3%-21%; P less than 0.001), Rocket samples (47% vs 67%; difference 20%, 95% CI; 12%-32%; P less than 0.001) or Multispatula samples (47% vs 76%; difference 29%, 95% CI 19-38%; P less than 0.001). When punch biopsies contained CIN, dyskaryotic cells were seen in 10% of Ayre's samples, 4.3% of Aylesbury samples, 8.3% of Rocket samples, and in no smear taken with the Multispatula. Obtaining a third smear with the Cytobrush did not substantially improve the detection rate of dyskaryosis. Neither the order of use of the spatulas, the form of initial treatment nor the size of the transformation zone had any apparent effect on the cytological detection of persistent CIN. CONCLUSIONS: We recommend that surveillance of patients who have received local ablative therapy for CIN should be by both cytology and colposcopy, and that cytological samples should be obtained using the Ayre's spatula.     

A novel keratanase-generated keratan sulfate antibody and its application to structural analysis of skeletal and corneal keratan sulfate

Introduction The objective of this study was to make monoclonal antibodies specific for keratanase‐generated neoepitopes in keratan sulfate (KS) and to use them along with existing KS monoclonal antibodies (e.g. 5D4, IB4) to investigate KS sulfation pattern motifs in connective tissue proteoglycans during development, ageing and disease. Methods Bovine nasal cartilage aggrecan (BNC A1D1) was trypsin digested, generating a range of GAG‐peptide fragments. The sample was then subjected to anion‐exchange and size exclusion chromatography to separate KS peptides from CS attachment domain fragments. Fractions were analysed by Western blotting for positive immunoreactivity for KS, then pooled and keratanase digested to generate ‘KS stub’ antigens. Immunization and fusions were carried out as previously described ( Caterson et al. 1983 ; Hughes et al. 1992 ). Screenings involved the use of a range of antigens; including keratanase vs. keratanase II‐digested bovine cartilage aggrecan and bovine corneal KS‐PGs. A new monoclonal antibody, BKS‐I, was identified that specifically recognized a keratanase‐generated neoepitope on both skeletal and corneal KS. This novel monoclonal antibody was used along with existing KS monoclonal antibodies 5D4 and 1B4 to investigate KS structure. Results and discussion Bovine trypsin‐generated aggrecan KS‐peptides were chondroitinase ABC treated and either keratanase or keratanase II treated. The digests were run on SDS‐PAGE and immunolocated with monoclonal antibody 5D4 (that recognizes linear disulfated N‐acetyl lactosamine disaccharide‐containing segments in KS) and the new ‘KS‐stub’ monoclonal antibody BKS‐I. Our results indicated that there was reduced monoclonal antibody 5D4 immunostaining after keratanase pretreatment. However, keratanase II digestion completely removed all 5D4 structural epitopes. In contrast, BKS‐I showed no immunostaining on the untreated KS‐peptides but strong staining on keratanase treated samples and no staining after keratanase II digestion. Similar patterns of immunoreactivity were observed with Western blot analysis of untreated, keratanase treated and keratanase II treated corneal KS‐PGs. Conclusion These data indicate that monoclonal antibody BKS‐I recognizes a nonreducing terminal neoepitope‐containing sulfated N‐acetylglucosamine adjacent to a nonsulfated lactosamine disaccharide. We also conclude that skeletal KS must have a structure with four possible variations opposed to the generic structures, proposed as being made of disulfated disaccharides at the nonreducing end, followed by a series of monosulfated disaccharides at the middle and nonsulfated disaccharides nearer the linkage region. 5D4 staining, observed after keratanase digestion, indicates that there must be a minimum structure of a pentasulfated hexasaccharide remaining on the KS chain ‘stubs’ near the linkage region of skeletal and corneal KS. The BKS‐I monoclonal antibody can be used to demonstrate differential substitution of KS GAG chains in the CS attachment region of cartilage aggrecan with ageing. It has also proven useful for immunohistochemical analyses identifying the sites of KS–PG association with collagen lamellae of cornea.