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G Rebello

Publications and source records attributed to G Rebello.

12 recordsLinked to original sources
PubMed2003

Analysis of RPGR in a South African family with X-linked retinitis pigmentosa: research and diagnostic implications.

Analysis of exon ORF15 of the RPGR gene has revealed a novel mutation in a South African family with X-linked retinitis pigmentosa (XLRP), which has implications for the rest of the family in terms of pre-symptomatic testing. The ability to test for this mutation will be beneficial for the accurate determination of carrier status in female relatives who may have been unaware of their risk before this study was performed. This work also highlights the need to be aware of the ramifications of mutation testing in what may appear to be small families. This is the first report of an RPGR ORF15 mutation in a South African family of mixed ancestry.

Base Sequence↗
PubMed2000

The borderline cervical smear: colposcopic and biopsy outcome.

AIMS: To review the outcome of women referred with smears showing borderline nuclear change (BNC), and to determine any differences in outcome if BNC was persistent, preceded by dyskaryosis, or followed treatment for cervical intraepithelial neoplasia (CIN). In addition, to determine criteria that might permit delineation of a BNC subtype, predictive of CIN. METHODS: The records of 178 women referred for colposcopy in 1993, with last smear showing BNC, were obtained from our laboratory database. The cytology, colposcopy, and biopsy follow up for a five year period were also obtained. The patients were divided into three categories according to their smear status before the last referral borderline smear: category 1, persistent BNC (n = 39); category 2, BNC preceded by dyskaryotic smears (n = 100); and category 3, BNC after treatment for CIN (n = 39). The referral borderline smears were reviewed on cases with negative outcome and those with a biopsy diagnosis of CIN2 and CIN3. RESULTS: In 50 women (28%) no biopsy was deemed necessary after colposcopic assessment. The biopsy results in the remaining 128 (72%) women were as follows: normal in 18 (10%), koilocytosis in 12 (7%), CIN1 in 45 (25%), CIN2 in 32 (18%), and CIN3 in 21 (12%) women. High grade lesions (CIN2, CIN3) were seen on biopsy in 14 of 39, 33 of 100, and six of 39 cases in category 1, category 2, and category 3, respectively. Blind review of the referral borderline smears from 53 women with a biopsy diagnosis of high grade lesions (32 CIN2, 21 CIN3) confirmed they were borderline in 23, upgraded them to mild dyskaryosis in 15, and found that 14 cases of isolated moderate or severe dyskaryotic cells had been missed originally. The borderline change was in mature squamous cells in five of 23 and in immature metaplastic epithelium in 18 of 23 cases. After smear review in 68 women with negative outcome, 36 smears were reclassified as negative in keeping with inflammation and atrophy, three were considered unsatisfactory, one was upgraded to CIN1, and 28 were confirmed as BNC. Of the latter, 25 of 28 were in mature squamous cells. The five year follow up on women with negative colposcopy (n = 50), negative loop excision of transformation zone (LETZ) (n = 18), and LETZ with koilocytosis (n = 12) showed subsequent high grade CIN on LETZ in 16, 0, and two patients, respectively. CONCLUSIONS: On referral of women for colposcopy with last smear showing BNC, the outcome was high grade CIN in over 30% of cases, irrespective of whether the borderline smear was preceded by another borderline smear or by a dyskaryotic smear. In contrast, in those referred because of BNC after treatment of CIN, high grade CIN was seen less frequently (15% of cases). Furthermore, in cases that necessitated loop excisions, high grade CIN was seen in 41%. This study also showed that BNC associated with inflammation or atrophy, or BNC in mature squamous cells, appears to have lower predictive value for CIN than those cases where BNC is associated with immature metaplastic epithelium. The use of terms such as "BNC favour reactive" for the former and "BNC favour dyskaryosis" for the latter is recommended, together with follow up by cytology and colposcopy, respectively.

Adult↗
PubMed1999

Effect of using templates on the information included in histopathology reports on specimens of uterine cervix taken by loop excision of the transformation zone.

AIM: To determine the change in information relayed from histopathologists to clinicians by using templates for reporting specimens of uterine cervix sampled by loop excision of the transformation zone (LETZ). METHODS: Minimum datasets for the information required from LETZ specimens received from the colposcopy clinic, Royal Infirmary, Edinburgh, were incorporated into templates on the clinical service computer (Pinnacle) of the pathology department, University of Edinburgh. Pathologists completed hard copy versions, which were transcribed into the computer templates for report generation. The effect of the changes on the quality of the pathology reports was studied. The number of cases in which each item in the dataset received comment in template generated reports was compared with that in traditional prose reports compiled before the use of the templates and in prose reports issued after the introduction of the templates. Questionnaire studies were undertaken of clinicians' and pathologists' opinions of the template reports. RESULTS: In the template reports nearly all items received comment in almost 100% of cases. In the prose reports issued both before and after the templates were in use, most items were mentioned in a significantly lower proportion of cases. Clinicians thought the template reports were clearer and the information could be more readily assimilated than from the prose versions. CONCLUSIONS: The use of template reports in these types of specimen allowed more consistent and detailed information transfer. The change appeared to result from the use of the templates rather than from increased awareness of the items to be reported.

Biopsy↗
PubMed1995

Chloride binding in the stroma of cultured human corneas.

In the ox cornea, more than half of the non-diffusible, matrix negative charge is derived from the binding of free chloride ions. Because the magnitude of the net matrix charge is the dominant factor which determines the degree of stromal swelling, we investigated whether this phenomenon, stromal chloride binding, also occurs in human corneal stroma. Intrastromal ion concentrations were measured with radio-isotopes when human (outdated Eye Bank) corneas or (fresh) bovine corneas, physically clamped to maintain a constant hydration, were incubated in buffered 154 mM NaCl. The intrastromal chloride ion concentration was compared to the normalized concentrations of trace quantities of radio-labelled acetate and lactate ions. For human corneas, the intrastromal chloride ion concentration was found to be significantly higher (P < 0.001, t-test) than the normalized concentrations of both acetate and lactate ([Cl]i = 142.5 +/- 0.9 mM, (n = 9); [acetate]i = 131.2 +/- 1.2 mM, (n = 8); [lactate]i = 131.9 +/- 1.5 mM, (n = 5); all values are mean +/- S.E.M.). The sodium ion concentration was elevated ([Na]i = 176.0 +/- 1.8 mM, (n = 9)). These results demonstrate that chloride binding occurs to a significant extent in cultured human corneal stroma and suggest that chloride binding may be evident in the native human cornea.

Animals↗
PubMed1994

Integrin expression in squamous neoplasia of the cervix.

Epithelial cell-basement membrane interactions are important in maintaining tissue architecture and function, and the anatomical and functional relationships between epithelial cells and their basement membranes are clearly altered in malignancy. These interactions are thought to be largely mediated by the integrins, a family of heterodimeric transmembrane glycoproteins, each consisting of an alpha and a beta chain. Epithelial integrins mainly belong to the beta 1 (VLA) subfamily, which forms receptors for matrix macromolecules such as fibronectin, laminin, and collagen. There is evidence that integrin expression changes in some epithelial malignancies, possibly in relation to invasive potential. Integrin expression in cervical neoplasia was studied by immunohistochemical examination of prospectively collected colposcopic biopsies. Well-characterized monoclonal antibodies against beta 1-4, alpha 1-6, and alpha V integrins were used to examine normal, koilocytic, and dysplastic cervical squamous epithelium, and invasive squamous carcinoma. beta 1, beta 4, alpha 2, alpha 3, alpha 6, and alpha V were expressed by the basal layer of normal cervical squamous epithelium and by dysplastic cells in CIN (cervical intraepithelial neoplasia) 1 and 2, with none being lost and no new chains acquired. In CIN3, these integrins were either expressed throughout the ectocervical epithelium or restricted to the basal layer. In the latter cases, integrin expression was retained to a greater degree by dysplastic squamous epithelium within endocervical glands. These patterns could not be correlated with age or smear history in the cases examined. Patterns of integrin expression in neoplastic cervical epithelium therefore differ from those of normal cervical epithelium.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Ceroid granuloma of the uterine cervix.

An excision biopsy was taken from a 59-year-old woman with a small dark-brown lesion on the anterior lip of the cervix. The histology revealed an ulcerated surface epithelium with a band-like infiltrate of pigment containing macrophages in the subepithelial zone. Histochemical examination of the specimen revealed that the pigment was ceroid. This is, to the best of our knowledge, the first case report of ceroid granuloma of the uterine cervix.

Ceroid↗
PubMed1992

Benign vaginal polyp: a histological, histochemical and immunohistochemical study of 20 polyps with comparison to normal vaginal subepithelial layer.

Twenty benign vaginal polyps from 18 patients, together with sections from normal vaginal epithelium, were studied histologically, histochemically using elastic van Gieson stain and immunohistochemically using monoclonal antibodies against vimentin, desmin and actin. The striking finding was the similarity, both histologically and immunohistochemically, of the stroma of vaginal polyps to that of the loose subepithelial layer found in normal vagina. The important difference was the marked degeneration of the elastic tissue, increased number of stellate and giant fibroblasts and subepithelial condensation of fibroblasts in the polyps. These findings support the hypothesis that vaginal polyps may represent a reactive hyperplasia of the loose subepithelial zone of the vaginal wall.

Adult↗
PubMed1992

Transient chloride binding as a contributory factor to corneal stromal swelling in the ox.

1. Investigations were made of the cation exchange capacity of fresh isolated ox corneal stroma (Q, units: mequiv fixed stromal charge/kg stromal fluid) at pH 7.4 over a variety of stomal hydrations (H, units: kg stromal fluid/kg dry tissue) both above and below the physiological hydration of 3.2, whilst the stromas were immersed in a variety of sodium chloride solutions (range 5-1000 mM). 2. At any particular salt concentration, the product QH (dry tissue exchange capacity, units: mequiv/kg dry tissue) appeared constant, over all the hydrations investigated. 3. Dry tissue exchange capacity (QH) varied, however, when the bathing salt concentration was altered. It varied between 55 mequiv/kg dry tissue (e.g. Q = 17 mequiv at H = 3.2) in 5 mM-NaCl to 240 mequiv/kg dry tissue (e.g. Q = 75 mequiv/l at H = 3.2) in 1000 mM-NaCl. 4. The variation of stromal exchange capacity in NaCl solutions of different concentrations was similar when detected by three independent procedures: stromal gel pressure measurements, intrastromal sodium ion distributions, and intrastromal electrical potentials. 5. Intrastromal chloride ion distributions were anomalous. Total chloride (measured by radio-isotopes) was consistently higher than that predicted by Donnan theory. 6. The data were consistent with Elliott's hypothesis that a fraction of intrastromal chloride ions bind to the corneal stromal matrix and in so doing contribute to the fixed negative charge of the stroma. 7. Our observations may be explained by a model of the cation exchange capacity of ox cornea which has two types of components. On is (at constant pH) invariant, and has a dry tissue exchange capacity of about 50 mequiv/kg dry tissue, and is probably generated by the sulphonic and carboxylic acid groups of the glycosaminoglycans. The other is explained by supposing it to consist of a chloride binding ligand which exhibits first order binding, is half occupied at ambient chloride concentrations of 300 mM, and has a total capacity of 240 mequiv/kg dry tissue. 8. Partial stromal extraction with 4 M-guanidine HCl indicated that the chloride binding ligand is not associated with the collagen molecules in the corneal stromal fibrils. 9. It is suggested that such a stromal chloride ion binding ligand would help to stabilize the hydration and transparency of the living cornea when it is exposed to environments of varying tonicity (such as in river or sea bathing).

Animals↗
PubMed1978

Pulmonary histological appearances in fatal paraquat poisoning.

The paper describes the histological appearances in the lungs from 11 fatal cases of paraquat poisoning. The study originated as an attempt to define the sequential changes in the condition and, from them, to assess the mode of action of the herbicide in the human. The main features of the "paraquat lung" include haemorrhage, extrusion of macrophages, oedema, "honeycombing", fibrosis and, rarely, epithelial hyperplasia. The indications are that the changes are progressive once a threshold tissue concentration has been reached. The appearances are compared to those in poisoning by hyperbaric oxygen and it is hypothesized that the toxic action of paraquat is to sensitize the lungs to oxygen at atmospheric pressure.

Adult↗