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PubMed1985

Effect of halothane on the natural-abundance 13C NMR spectra of excised rat brain.

Halothane increases the intensity of the 30.5- and 129-ppm resonances in 13C nuclear magnetic resonance spectra of excised rat brain, of phospholipid vesicles prepared from chloroform-methanol extract of rat brain, and of brain excised from rats anesthetized with halothane. The 13C spin-lattice relaxation times of the 30.5- and 129-ppm resonances are increased in excised brain, or phospholipid vesicles, upon addition of halothane, and they are also increased in brain excised from rats anesthetized with halothane. Excised brain and its membrane-rich subcellular fractions interact with [14C]halothane reversibly. The interaction is virtually abolished when the phospholipids are extracted from the brain. The [14C]halothane content of the brain membranes is correlated with the halothane-induced increase in the integral of the 129-ppm resonance. From this correlation and from the phospholipid content of the membranes, a halothane concentration of 3.34 mM and a partition of 0.057 mol of halothane/mol of phospholipid may be calculated in the brain of anesthetized rats.

Animals↗

PubMed1977

Excision of 7-bromomethylbenz[a]anthracene--DNA adducts in replicating mammalian cells.

The excision of 7-bromomethylbenz[a]anthracene--DNA adducts was studied in two cell lines (HeLa S-3 and Chinese hamster V-79379A). In both cell lines, carcinogen-modified adenine residues were excised more readily than the modified guanine residues and the percentage of the total products excised decreased after treatment with higher concentrations of carcinogen. At the highest concentrations used in the Chinese hamster cells, neither DNA synthesis nor excision was detected. The lowest concentration used for these cells permitted almost 100% survival and all the DNA was replicated in a 30-h interval even though 50% of the initial damage was still present. The two- to threefold lower sensitivity of the Chinese hamster cells (compared with the Hela cells) to the carcinogen is attributed to this capacity for replication of DNA on a damaged template since the two cell lines' capacities for excision of the chemical damage were found to be comparable.

Benz(a)Anthracenes↗

PubMed1998

Excision of Ds1 from the genome of maize streak virus in response to different transposase-encoding genes.

We have previously established a reverse genetic system for studying excision of the transposable element Ds1 in maize plants. Ds1 carried by the genome of maize streak virus (MSV) is introduced into maize plants by agroinfection. Excision of Ds1 from the MSV genome depends on the presence of an active Ac element in the recipient maize plants. With the purpose of exploiting MSV-Ds1 as vector for maize transformation, we studied different genes encoding the transposase (TPase) for their efficiency of activating Ds1 excision. These genes were inserted in the same T-DNA carrying MSV-Ds1 and introduced into maize plants by Agrobacterium-mediated transformation. We showed that the wild-type TPase transcribed by the 2' promoter produced much higher efficiency of Ds1 excision than that transcribed by the Ac promoter. In contrast to what had been observed in tobacco and petunia, the truncated TPase (103-807) lacking the amino-terminal 102 amino acids gave a much more reduced Ds1 excision efficiency than the wild-type TPase when both genes were transcribed by the 2' promoter.

DNA Transposable Elements↗

PubMed2002

Atypical cells in human cutaneous re-excision scars for melanoma express p75NGFR, C56/N-CAM and GAP-43: evidence of early Schwann cell differentiation.

BACKGROUND: A common problem in the routine examination of melanoma re-excision scars occurs when a few or rare mildly atypical cells are present within the scar, raising the question of residual disease. Little is known about the derivation of these cells. Because the normal cutaneous wound-healing process is reparative, we hypothesized that these atypical cells may be reactive proliferating Schwann cell precursors. METHODS: The expression of the Schwann cell differentiation markers p75NGFR, CD56/N-CAM and GAP-43 was examined by immunohistochemistry in scars of wide local re-excisions for melanoma and non-melanoma tumors. Expression of S100, gp100 (with HMB45) and MART1 was also analyzed by immunohistochemistry. RESULTS: All melanoma and non-melanoma re-excision specimens contained mildly atypical, spindled or epithelioid cells within the scar. They varied in number from case to case and expressed S100, p75NGFR, CD56/N-CAM or GAP-43 but not gp100 (with HMB45) or MART1. Rare epithelioid non-melanoma cells within the superficial dermis expressed MART-1. CONCLUSIONS: Atypical cells are present in re-excision scars from melanoma and non-melanoma cases. They demonstrate early Schwann cell differentiation and appear to proliferate during the scarring process. The use of anti-MART-1 alone in the examination of melanoma re-excisions specimens may be inadequate as it may label rare, superficially located, non-melanoma cells within the scar.

Adult↗

PubMed1980

Excision sequences in the mitochondrial genome of yeast.

It is well established that spontaneous cytoplasmic 'petite' mutants of Saccharomyces cerevisiae have mitochondrial genome units in which an excised segment of the parental wild-type genome has been tandemly amplified (Fig. 1), so that the excised segment becomes the repeat unit of the petite genome; the latter may in turn undergo further deletions leading to secondary petite genomes having shorter repeat units (see ref. 1 for a brief review). Recent investigations on the mitochondrial genomes of several spontaneous petite mutants have shown that frequently the ends of the excised segment correspond to short sequences of the wild-type genome which are extremely rich in GC, the GC clusters; alternatively, they seem to be located in the long AT-rich stretches, the AT spacers, which form at least half of the genome. As sequence repetitions have been demonstrated in both GC clusters and AT spacers, it is very likely that excision takes place by a mechanism involving illegitimate site-specific recombination events between homologous sequences, as previously postulated. We show here that the sequences involved in the excision of a particular spontaneous petite genome are direct nucleotide repeats located in the AT spacers.

Base Sequence↗

PubMed1997

Long-term results of corneal wedge excision for pellucid marginal degeneration.

PURPOSE: A retrospective study reporting long-term visual and astigmatic results of patients with pellucid marginal degeneration (PMD) treated by corneal wedge excision. METHODS: The notes of 9 patients (10 eyes) treated by corneal wedge excision were reviewed. All patients had typical PMD and were treated by excision of an inferior crescent of diseased corneal tissue. The excised area measured approximately 2 mm in width and extended from the 4 o'clock to the 8 o'clock meridian. All thinned corneal tissue was removed. Normal-thickness corneal stroma was then reapposed with 10/0 nylon or 10/0 polypropylene sutures. Post-operative selective suture removal was performed until a satisfactory visual and astigmatic result was achieved. This was guided by refraction, keratometry and photo-keratoscopy results. Pre-operative best corrected visual acuity ranged from 6/12 to 6/60 with an associated mean keratometric astigmatism of +13.8 dioptres (range 8-25 dioptres, axis range 30 degrees-175 degrees). Mean follow-up was 59 months (range 14-138 months). RESULTS: Post-operatively a stable corrected visual acuity of 6/9 or better was achieved in all cases in a mean time of 5.4 months (range 3-12 months). Mean post-operative keratometric astigmatism was 1.4 dioptres (range 0.5-4 dioptres). Over the course of follow-up long-term astigmatic drift (LTAD) was noted, mean 2.1 dioptres (range 0.5-5.5 dioptres). Three patients developed mild inferior pannus related to peripherally sited sutures. One case developed apparent corneal hydrops within the corneal wound after 9 years of follow-up. CONCLUSIONS: We believe that corneal wedge excision offers an excellent surgical result for patients with PMD, although modification of the technique may be required to improve long-term astigmatic drift.

Adolescent↗

PubMed2005

En bloc excision of intraocular epithelial cystic downgrowth using syngeneic auricular cartilage.

AIM: To describe the surgical management of epithelial cystic downgrowth by en bloc excision and use of syngeneic auricular cartilage in two children. STUDY DESIGN: Retrospective interventional case series. METHOD: The charts of two patients treated for epithelial cystic downgrowth with en bloc excision and auricular cartilage transplant were reviewed. Details of ocular history, preoperative and postoperative visual acuity, intraocular pressure, ocular examination findings, surgical procedure and subsequent management were noted. RESULTS: Two children aged 4 and 6 years, with epithelial cysts who underwent en bloc excision were identified. The cysts had developed following penetrating eye injury. Surgery involved en bloc resection of the cyst and associated tissue, and replacement of the excised corneoscleral tissue with syngeneic auricular cartilage. One patient additionally required synechiolysis, discission of a secondary cataract and anterior vitrectomy. In both cases, the epithelial tissue was successfully removed and the auricular cartilage transplant was well-apposed. Visual acuity remained at the preoperative level in the first patient due to amblyopia; in the second patient visual acuity improved to 6/7.5 with mild astigmatic correction. CONCLUSION: En bloc excision provides the most definitive surgical treatment of cystic epithelial downgrowth. Auricular cartilage may be used for sclerokeratoplasty when donor cornea or sclera is unavailable.

Anterior Chamber↗

PubMed2006

Nonpreserved human amniotic membrane transplantation for conjunctival reconstruction after excision of extensive ocular surface neoplasia.

PURPOSE: To report our experience on the use of nonpreserved human amniotic membrane transplantation (AMT) in ocular surface reconstruction after excision of extensive ocular surface neoplasia (OSN). DESIGN: Prospective noncomparative interventional case series. PARTICIPANTS: In all, 10 eyes of 10 consecutive patients with extensive OSN involving various areas of limbus, conjunctiva, and cornea (conjunctival carcinoma in situ, four eyes; squamous cell carcinoma, three eyes; malignant melanoma, two eyes; conjunctival-orbital lymphangioma, one eye) were included in this prospective noncomparative interventional case series. After excision of the neoplasia with 3-4 mm tumour-free margins, double freeze-thaw cryotherapy was applied to the margins of the remaining conjunctiva, and nonpreserved human amniotic membrane graft was sutured to the adjacent conjunctiva using 8/0 vicryl sutures and cornea using 10/0 nylon sutures, with the epithelial side facing up to cover the bare sclera and cornea. Postoperatively, topical corticosteroids were used for 3 months. RESULTS: After tumour excision and AMT, a satisfactory result with a wet, stable conjunctiva, and rapid and complete healing was observed in all eyes. Over a mean follow-up of 10.0 months (range, 6-27 months), all but one eye remained free of tumour recurrence. In one eye with conjunctival melanoma, there was a small recurrence, which was treated with excision and cryotherapy. Treatment complications were partial stem cell deficiency in two eyes and symblepharon formation in one eye. Immune graft rejection was not encountered. CONCLUSION: Nonpreserved human AMT appears to be useful for reconstruction of ocular surface following excision of extensive OSN.

Adult↗

PubMed2004

A quality-of-life study in high-risk (thickness > = or 2 mm) cutaneous melanoma patients in a randomized trial of 1-cm versus 3-cm surgical excision margins.

A quality-of-life study was carried out to test the hypothesis that melanoma patients treated with a 3-cm margin of excision suffer greater impairment of their quality of life than those treated with a 1-cm margin. The secondary aim was to determine the predictors of a poor patient perception of their excision scar. A postal questionnaire study was carried out using Hospital Anxiety and Depression (HAD), Psychosocial Adjustment of Illness Scale-Self-Report (PAIS-SR), Medical Outcomes Survey-Short Form 36 (MOS-SF36), and the Cassileth Scar questionnaires. Data were collected from 426 of the 537 patients who were mailed the questionnaires (response rate 79%). Fourteen percent had clinically significant anxiety and 5% had significant depression. A poor attitude toward quality of health care was associated with youth. Patients treated with a 3-cm margin excision had significantly poorer mental and physical function 1 mo after surgery, which disappeared within 6 mo. The greater difficulties experienced by the 3-cm margin group were particularly in their domestic, sexual, and social roles. Women, younger patients, those with poor physical and mental function after surgery, and those treated by a 3-cm margin were more likely to report a poorer perception of their scar. The poorer scar perception of patients in the 3-cm group persisted throughout the study period. Use of a 3-cm margin of excision for melanoma is associated with significantly more morbidity than use of a 1-cm margin, but this effect disappears in 6 mo. Patients treated by 3-cm excision were more likely, however, to have a persistent poor view of their scar. Youth and being female were also predictors of poor perception of the scar.

Aging↗

PubMed2000

Head and neck basal cell carcinoma: treatment using a 2-mm clinical excision margin.

Treatment of basal cell carcinoma (BCC) should completely remove the tumour whilst preserving the maximum amount of normal surrounding skin. Therefore, treatment is a compromise between safe excision margins and obtaining a satisfactory cosmetic result. We report the results of a prospective study of 63 patients who underwent excision of well-demarcated BCCs in the head and neck region. The surgical excision margin used was 2 mm. Histological assessment confirmed complete excision in 95% and there was no evidence of recurrence of the BCC over a 24-month follow-up period in all patients. We propose that a clinical excision margin of 2 mm is adequate for treatment of simple, well demarcated BCCs arising in the head and neck.

Adult↗

PubMed1999

The excision of polydnavirus sequences from the genome of the wasp Cotesia congregata (Braconidae, microgastrinae) is developmentally regulated but not strictly restricted to the ovaries in the adult.

Cotesia congregata polydnavirus (CcPDV) is essential for the successful parasitism of Manduca sexta larvae by the braconid wasp Cotesia congregata. In the absence of PDV, parasitoid eggs are encapsulated. Molecular analysis has demonstrated that polydnavirus sequences are integrated in the wasp chromosomes, and an ultrastructural analysis has shown that PDV replication occurs in the calyx region in the ovaries of the wasp. The bracovirus sequences appear to be excised from the wasp genome in the calyx cells where the virus replicates. Following excision of the virus sequences, the flanking sequences are rejoined. We analysed the production of two polydnavirus circles during wasp development and in different body parts of the adults of both sexes. Our study indicates that the excision of viral sequences is developmentally regulated, beginning in the pupal stage. In the adult wasp, excision occurs ubiquitously. However, regulation in the adult seems to occur only in diploid individuals, as no excision is detected in haploid males produced from virgin females.

Animals↗

PubMed2001

Xis protein of the conjugative transposon Tn916 plays dual opposing roles in transposon excision.

The binding of Tn916 Xis protein to its specific sites at the left and right ends of the transposon was compared using gel mobility shift assays. Xis formed two complexes with different electrophoretic mobilities with both right and left transposon ends. Complex II, with a reduced mobility, formed at higher concentrations of Xis and appeared at an eightfold lower Xis concentration with a DNA fragment from the left end of the transposon rather than with a DNA fragment from the right end of the transposon, indicating that Xis has a higher affinity for the left end of the transposon. Methylation interference was used to identify two G residues that were essential for binding of Xis to the right end of Tn916. Mutations in these residues reduced binding of Xis. In an in vivo assay, these mutations increased the frequency of excision of a minitransposon from a plasmid, indicating that binding of Xis at the right end of Tn916 inhibits transposon excision. A similar mutation in the specific binding site for Xis at the left end of the transposon did not reduce the affinity of Xis for the site but did perturb binding sufficiently to alter the pattern of protection by Xis from nuclease cleavage. This mutation reduced the level of transposon excision, indicating that binding of Xis to the left end of Tn916 is required for transposon excision. Thus, Xis is required for transposon excision and, at elevated concentrations, can also regulate this process.

Base Sequence↗

PubMed2002

Characterization of Exc, a novel protein required for the excision of Bacteroides conjugative transposon.

Conjugative transposons are integrated elements that excise from the chromosome, then transfer by conjugation to a recipient in which they integrate once again. Recently, a gene, designated exc, was shown to be essential for excision of the Bacteroides conjugative transposon (CTnDOT) from the chromosome. The deduced amino acid sequence of Exc had low amino acid sequence similarity to DNA topoisomerase III, an enzyme that relaxes DNA supercoils. This similarity raised the question of whether Exc protein was a topoisomerase and, if so, whether topoisomerase activity might contribute to the excision process. Here, we demonstrate that Exc does have topoisomerase activity in vitro. Exc relaxed supercoiled DNA, had a conserved tyrosine as its active site and required magnesium ions for its relaxation activity. However, although mutation of the catalytic tyrosine of Exc to phenylalanine abolished the ability of the enzyme to relax DNA supercoils in vitro, the mutation did not abolish the ability of the protein to mediate excision in vivo. This surprising result suggests that CTnDOT excision does not rely on the topoisomerase activity of Exc in vivo.

Bacterial Proteins↗

PubMed2002

Incomplete excision of basal cell carcinomas: a retrospective audit.

BACKGROUND: The reported rates of incomplete excision of basal cell carcinoma (BCC) vary widely (5-25%) among centres around the world. Incomplete excision of skin malignancy is one of the 57 clinical indicators developed by the Royal Australasian College of Surgeons and the Australian Council on Healthcare Standards to act as a measure of the standard of surgical care. The study aims to determine the rate of incomplete excision of BCC at a major cancer centre. METHODS: Computerized data and patients' records were reviewed. From January 1997 to June 2000, a total of 3558 BCC were surgically excised with curative intent, of which 223 were reported to have been removed incompletely. RESULTS: The overall rate of incomplete excision was 6.3%. CONCLUSIONS: Given the limitations of a retrospective audit and reliability of the data, this result nevertheless compares favourably with reported figures in the literature.

Adult↗

PubMed2003

Squamous cell carcinoma of the lip: is there a role for adjuvant radiotherapy in improving local control following incomplete or inadequate excision?

BACKGROUND: The treatment of squamous cell carcinoma of the lip with surgery is usually curative but incomplete/inadequate excision may be associated with recurrence and poor outcome. There is no consensus in the literature on the definition of an adequate excision margin. METHODS: Patients treated for squamous cell carcinoma of the lip at Westmead Hospital, Sydney, between 1980 and 2000 were eligible for inclusion. Polytomous logistic regression analysis was undertaken to assess for predictors of recurrence. Recurrence-free and overall survival were calculated using Kaplan-Meier survival curves. RESULTS: A total of 130 patients was identified. Median age at diagnosis was 64 years (23-97 years). Most lesions (90%) were located on the lower lip in 96 (74%) male patients. Median follow-up duration was 54 months (0-189 months). Most patients -presented with T1 lesions (75%). Initial treatment was surgery (39%), radiotherapy (48%) or both (13%). Twenty-seven per cent of excised lesions had a close (< or =2 mm) or positive margin. A total of 40 patients (31%) had recurrence (18% lymph nodes, 11% lip and 2% both). In the surgery group recurrence was significantly more likely with close or positive margins (P = 0.05). The 2 year -recurrence-free survival was 82% and 54% for radiotherapy and surgery, respectively (P < 0.001). The 2 year overall survival was similar (90% radiotherapy vs 100% surgery; P = 0.58). CONCLUSION: Incomplete or inadequate excision of some lip cancers results in local recurrence. If re-excision is not feasible -surgeons should consider the role of adjuvant radiotherapy in improving local control.

Adult↗

PubMed2001

Rectal excision with coloanal anastomosis for superficial distal third rectal cancer: survival and local recurrence.

OBJECTIVE: Appropriate surgical treatment of distal third rectal cancer limited to bowel wall (i.e. T1 or T2) in medically operable patients is controversial. Transanal excision can deprive some patients of accurate pathological staging, prognosis and cure. In contrast abdominoperineal resection has considerable practical and psychosocial problems largely related to a permanent colostomy. We hypothesize that superficial distal rectal tumours can be effectively treated with rectal excision and coloanal anastomosis. SUBJECTS AND METHODS: Prospective oncological study of 80 patients with distal third superficial rectal carcinomas treated by complete rectal excision with coloananl anastomosis from December 1977 to January 1993 was carried out. The resected specimens were examined for depth of spread and number of histologically positive nodes. The actuarial local recurrence and survival rates for superficial node-negative and node-positive tumours were analysed independently. RESULTS: Seventy-eight patients had complete postoperative assessment. Thirty-one percent had received low-dose preoperative neo-adjuvant radiotherapy (3500 rads). Mean follow-up time in all patients was 70 months on average. The lymph node involvement rate for T1 and T2 tumours was 12.5 and 15.6%, respectively. The local recurrence rates for patients with (T1/T2) N0 and (T1/T2) N1 were 1.5 and 16.7%, respectively, and the five year actuarial survival rates were 96.6 and 90%, respectively. The overall local recurrence was 3.8% with five-year actuarial survival of 95.8%. CONCLUSIONS: Lymph node involvement in superficial tumours is not rare. Rectal excision with coloanal anastomosis results in a high cure rate especially for node-positive superficial tumours. This treatment strategy avoids the psychological trauma of colostomy following abdominoperineal resection and the potential risk of undertreatment by local excision.

Journal Article↗

PubMed2003

Local excision of rectal carcinoma not-exceeding the muscularis layer.

AIM: The aim of the study was to compare the results of treatment by local excision of two different clinical stages of the rectal cancer. MATERIAL AND METHODS: Fifty-eight patients with early rectal carcinoma were operated on during the last 26 years using different methods of local excision. The carcinomas were initially assessed as not-exceeding the muscularis layer of the rectal wall. The tumours, localized up to 12 cm from the anal margin, were removed by means of "parachute" excision (47 patients). In 6 patients, carcinoma localized in the central part of rectum, was excised by means of the Localio method. Transanal endoscopic microsurgery was applied in 5 cases of carcinoma localized on the depth of 5-20 cm from the anal margin. RESULTS: After local excision the patients were divided into two groups: I, tumours of low degree of malignancy, not exceeding submucosal layer (26 patients); II, tumours of low or median degree of malignancy with infiltration of muscularis layer (32 patients). There was a significant difference in cancer relapses between groups I and II. One patient in group I and 9 in group II developed local recurrences (P < 0.05) and 5 patients in group II had neoplastic dissemination (15.6%). CONCLUSIONS: Best results were obtained in patients with carcinoma not exceeding submucosal membrane. In cases of rectal muscular layer infiltrations, the risk of carcinoma relapses was markedly higher. The use of transanal endoscopic microsurgery has permitted removal of tumours from the upper rectum.

Adult↗

PubMed2003

Reconstruction of skin defects after radical excision of anorectal giant condyloma acuminatum: 6 cases.

The authors report six cases of giant condyloma accuminatum and evaluate the use of mesh-skin grafts in covering the skin defect after radical local excision of perianal giant condyloma acuminatum. Medical records of six patients suffering from the giant condylomata acuminata and treated surgically at the Department of Surgery, Clinical Hospital Center Zagreb, were examined. Use of mesh-skin grafts in covering the skin defect after radical local excision of GCA was compared to other methods of treating the skin defect after radical excision of perianal lesions such as secondary wound healing. Four patients were treated by radical local excision and two patients were treated by abdominoperineal resection. There were partial graft failures (satisfactory result) in all patients and complete healing took about 3 to 4 weeks from time of grafting. A mesh-skin graft was used to cover the skin defect. There were no recurrences, wound infections, wound bleeding, hypertrophic scars, or mesh-like skin appearance of the recipient site. Therefore a good cosmetic and functional result was achieved. Use of mesh-grafts in covering the wounds after radical excision of anorectal giant condylomata acuminata compares favorably to healing by secondary intention in terms of wound healing time, and gives good functional and cosmetic results.

Adult↗