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PubMed2001

[Recurrence of finger tendon giant cell tumors after excision through a "shark teeth" approach. Report of 25 cases].

Local recurrences after excision of a giant cell tumor of the tendon sheath are classically related to incomplete excision. We have review a special group of circumferential tumors excised through a huge approach. Twenty-six circumferential tumors were excised between 1985 and 1998, through a special incision described by the senior author. It is composed of four triangular flaps drawn around the finger, one dorsal, one palmar (both proximally based) and two lateral (distally based). Six presented already with a recurrence of previous operations (mean 2.5 interventions). Some anatomical neighboring structure was "invaded" in all except one case. However the approach allows for a macroscopically satisfactory excision. Twenty-five patients were reviewed by an independent observator after a mean follow-up of six years. Six patients (24%) presented a recurrence after a mean postoperative delay of 17 months. Among them five have been already operated (83%) and five had multiple tumors. Satisfactory excision does not prevent recurrence and two types of distinct tumors exist. Recent immunohistological studies give support to this view and such examination is recommended.

Adult↗

PubMed1999

Effect of topical and subcutaneous epinephrine in combination with topical thrombin in blood loss during immediate near-total burn wound excision in pediatric burned patients.

Bleeding is a major concern during burn wound excision. To evaluate the efficacy of epinephrine to control blood loss, a prospective cohort of 42 pediatric patients were examined. Half of the patients received topical epinephrine to excised wounds and donor sites and subcutaneous epinephrine to scalp donor sites during total burn excision, while the other half did not. Both groups of patients received bovine topical thrombin sprayed at a concentration of 1000 U/ml. Mean blood loss in the epinephrine group was 1090 ml (range 20-4000), with a blood loss of 0.48+/-0.12 ml/cm2 excised, while the control group was 1271 ml (range 40-3750) and 0.51+/-0.15 ml/cm2. Differences in preoperative and postoperative hematocrits were respectively -3.4+/-7.8 and -4.6+/-7.5. The groups were not statistically different in this analysis. Subgroup analysis by age, burn size and time of burn to excision showed no differences. No complications or side effects of the use of the vasopressor solution occurred. In conclusion, no differences in blood loss were found between the groups. The routine use of local epinephrine during total wound excision in combination with topical thrombin in pediatric patients operated within 24 h after the admission may not be necessary. The effect of topical thrombin on blood loss should be analyzed separately.

Administration, Topical↗

PubMed1990

[Excision of the lunate bone in Kienboeck's disease. Report of 17 cases].

We have performed excision of the lunate in 17 cases (partial excision of the lunate in two cases and total excision of the lunate in 15 cases) for the Decoulx stage III Kienböck's disease with an average follow-up of 11 years 7 months. Excellent and good results were obtained in 11 cases ont of 17 (65 per cent). After partial excision of the lunate, the shape of the lunate was conserved. After total excision of the lunate, the rearrangement of the remaining carpus maintained mobility and satisfactory force. Excellent and good results were obtained for pain in 14 cases out of 17. Total excision of the lunate gave poor results for the three heavy manual workers out of 12 manual workers after long-term follow-up.

Adult↗

PubMed1999

RecBC and RecF recombination pathways and the induced precise excision of Tn10 in Escherichia coli.

Mitomycin C (MMC) treatment or mutations in uvrD enhance the frequency of Tn10 precise excision. We have shown previously that several repair-recombination genes, such as recA, ruv and recF are involved in the induced excision process. In this study, we find that other genes belonging to the RecBC and RecF sexual recombination pathways also participate in this process since mutations in recB, sbcB or recO diminish, though to different degrees, the frequency of Tn10 precise excision induced by MMC treatment or by uvrD mutants. Pairwise combinations of some of these mutations were also tested for Tn10 induced precise excision; most of these double mutants showed additive effects in reducing the frequency of the excision process. The results of these studies suggest that recombinational-repair genes, particularly recF, sbcB and recO have different roles in the induced excision of Tn10 than in recombinational mating.

Adenosine Triphosphatases↗

PubMed1994

Reconstitution of the DNA base excision-repair pathway.

BACKGROUND: The base excision-repair pathway is the major cellular defence mechanism against spontaneous DNA damage. The enzymes involved have been highly conserved during evolution. Base excision-repair has been reproduced previously with crude cell-free extracts of bacterial or human origin. To further our understanding of base excision-repair, we have attempted to reconstitute the pathway in vitro using purified enzymes. RESULTS: We report here the successful reconstitution of the base excision-repair pathway with five purified enzymes from Escherichia coli: uracil-DNA glycosylase, a representative of the DNA glycosylases that remove various lesions from DNA; the AP endonuclease IV that specifically cleaves at abasic sites; RecJ protein which excises a 5' terminal deoxyribose-phosphate residue; DNA polymerase I; and DNA ligase. The reaction proceeds with high efficiency in the absence of additional factors in the reconstituted system. Four of the enzymes are absolutely required for completion of the repair reaction. An unusual feature we have discovered is that the pathway branches after enzymatic incision at an abasic DNA site. RecJ protein is required for the major reaction, which involves replacement of only a single nucleotide at the damaged site; in its absence, an alternative pathway is observed, with generation of longer repair patches by the 5' nuclease function of DNA polymerase I. CONCLUSIONS: Repair of uracil in DNA is achieved by a very short-patch excision-repair process involving five different enzymes. No additional protein factors seem to be required. There is a minor, back-up pathway that uses replication factors to generate longer repair patches.

Bacterial Proteins↗

PubMed2001

Comparison of topically applied 0.2% glyceryl trinitrate ointment, incision and excision in the treatment of perianal thrombosis.

BACKGROUND AND AIMS: Topically applied 0.2% glyceryl trinitrate ointment to the anal region, incision and excision were compared in the treatment of perianal thrombosis, in order to establish which method is the best in terms of pain relief, number of recurrences and the appearance of anal skin tags. PATIENTS AND METHODS: A total of 150 patients were randomly divided into three groups of 50, each group being treated by one of the above-mentioned methods. The results of the treatment were evaluated during the first 4 days, after one month and after one year. RESULTS: A statistically significant reduction of pain was achieved by excision if compared with incision or conservative treatment with glyceryl trinitrate (p<0.001), and by conservative treatment with glyceryl trinitrate if compared with incision (p<0.01 on the 4th day of follow-up. Comparison of patients treated by the three different methods did not reveal any significant difference between these methods after one month (p>0.05). After one year the number of recurrences was significantly reduced after excision if compared with incision (p<0.05) or conservative treatment with glyceryl trinitrate (p<0.05). The number of patients without symptoms was significantly greater after excision if compared with incision or conservative treatment with glyceryl trinitrate (p<0.001). The number of patients with anal skin tags was significantly reduced in patients treated by excision if compared with incision (p<0.001) or glyceryl trinitrate treatment (p<0.001). CONCLUSION: Excision is a significantly better method of treatment of perianal thrombosis than incision or topically applied 0.2% glyceryl trinitrate ointment.

Administration, Topical↗

PubMed1995

Nucleotide excision repair DNA synthesis by DNA polymerase epsilon in the presence of PCNA, RFC, and RPA.

In eukaryotes, nucleotide excision repair of DNA is a complex process that requires many polypeptides to perform dual incision and remove a segment of about 30 nucleotides containing the damage, followed by repair DNA synthesis to replace the excised segment. Nucleotide excision repair DNA synthesis is dependent on proliferating cell nuclear antigen (PCNA). To study gap-filling DNA synthesis during DNA nucleotide excision repair, UV-damaged DNA was first incubated with PCNA-depleted human cell extracts to create repair incisions. Purified DNA polymerase delta or epsilon, with DNA ligase, was then used to form the repair patch. DNA polymerase delta could perform repair synthesis and was strictly dependent on the presence of both PCNA and replication factor C, but gave rise to a very low proportion of complete, ligated circles. The presence of replication protein A (which is also required for nucleotide excision repair) did not alter this result, while addition of DNase IV increased the fraction of ligated products. DNA polymerase epsilon, on the other hand, could fill the repair patch in the absence of PCNA and replication factor C, and most of the products were ligated circles. Addition of replication protein A changed the situation dramatically, and synthesis by polymerase epsilon became dependent on both PCNA and replication factor C. A combination of DNA polymerase epsilon, PCNA, replication factor C, replication protein A, and DNA ligase I appears to be well-suited to the task of creating nucleotide excision repair patches.

Bacteriophage T4↗

PubMed1994

Pre-steady-state kinetic analysis of sequence-dependent nucleotide excision by the 3'-exonuclease activity of bacteriophage T4 DNA polymerase.

The effects of local DNA sequence on the proofreading efficiency of wild-type T4 DNA polymerase were examined by measuring the kinetics of removal of the fluorescent nucleotide analog 2-aminopurine deoxynucleoside monophosphate (dAPMP) from primer/templates of defined sequences. The effects of (1) interactions with the 5'-neighboring bases, (2) base pair stability, and (3) G.C content of the surrounding sequences on the pre-steady-state kinetics of dAPMP excision were measured. Rates of excision dAPMP from a primer 3'-terminus located opposite a template T (AP.T base pair) increased, over a 3-fold range, with the 5'-neighbor to AP in the order C < G < T < A. Rates of removal of dAPMP from AP.X base pairs located in the same surrounding sequence increased as AP.T < AP.A < AP.C < AP.G, which correlates with the decrease in the stabilities of these base pairs predicted by Tm measurements. A key finding was that AP was excised at a slower rate when mispaired opposite C located next to four G.C base pairs than when correctly paired opposite T next to four A.T base pairs, suggesting that exonuclease mismatch removal specificities may be enhanced to a much greater extent by instabilities of local primer termini than by specific recognition of incorrect base pairs. In polymerase-initiated reactions, biphasic reaction kinetics were observed for the excision of AP within most but not all sequence contexts. Rates of the rapid phases (30-40 s-1) were relatively insensitive to sequence context. Rapid-phase rates reflect the rate constants for exonucleolytic excision of dAPMP from melted primer termini for both correct and incorrect base pairs and were roughly comparable to rates of removal of dAPMP from single-stranded DNA (65-80 s-1). Rates of the slow phases (3-13 s-1) were dependent on sequence context; the slow phase may reflect the rate of switching from the polymerase to the exonuclease active site, or perhaps the conversion of a primer/template terminus from an annealed to a melted state in the exonuclease active site. These data, using wild-type T4 DNA polymerase and two exonuclease-deficient T4 polymerases, support a model in which exonuclease excision occurs on melted primer 3'-termini for both mismatched and correctly matched primer termini, and where specificity favoring removal of terminally mismatched base pairs is determined by the much larger fraction of melted-out primer 3'-termini for mispairs compared to that for correct pairs.

2-Aminopurine↗

PubMed2001

Substrate specificity and excision kinetics of Escherichia coli endonuclease VIII (Nei) for modified bases in DNA damaged by free radicals.

Endonuclease VIII (Nei) is one of three enzymes in Escherichia coli that are involved in base-excision repair of oxidative damage to DNA. We investigated the substrate specificity and excision kinetics of this DNA glycosylase for bases in DNA that have been damaged by free radicals. Two different DNA substrates were prepared by gamma-irradiation of DNA solutions under N(2)O or air, such that they contained a multiplicity of modified bases. Although previous studies on the substrate specificity of Nei had demonstrated activity on several pyrimidine derivatives, this present study demonstrates excision of additional pyrimidine derivatives and a purine-derived lesion, 4,6-diamino-5-formamidopyrimidine, from DNA containing multiple modified bases. Excision was dependent on enzyme concentration, incubation time, and substrate concentration, and followed Michaelis-Menten kinetics. The kinetic parameters also depended on the identity of the individual modified base being removed. Substrates and excision kinetics of Nei and a naturally arising mutant form involving Leu-90-->Ser (L90S-Nei) were compared to those of Escherichia coli endonuclease III (Nth), which had previously been determined under experimental conditions similar to those in this study. This comparison showed that Nei and Nth significantly differ from each other in terms of excision rates, although they have common substrates. The present work extends the substrate specificity of Nei and shows the effect of a single mutation in the nei gene on the specificity of Nei.

DNA Damage↗

PubMed1997

Reconstitution of human base excision repair with purified proteins.

Base excision repair is a major mechanism for correcting aberrant DNA bases. We are using an in vitro base excision repair assay to fractionate and purify proteins from a human cell extract that are involved in this type of repair. Three fractions are required to reconstitute base excision repair synthesis using a uracil-containing DNA as a model substrate. We previously showed that one fraction corresponds to DNA polymerase beta. A second fraction was extensively purified and found to possess uracil-DNA glycosylase activity and was identified as the product of the UNG gene. A neutralizing antibody to the human UNG protein inhibited base excision repair in crude extract by at least 90%. The third fraction was highly purified and exhibited apurinic/apyrimidinic (AP) endonuclease activity. Immunoblot analysis identified HAP1 as the major polypeptide in fractions possessing DNA repair activity. Recombinant versions of UNG, HAP1, and DNA polymerase beta were able to substitute for the proteins purified from human cells. Addition of DNA ligase I led to ligated repair products. Thus, complete base excision repair of uracil-containing DNA was achieved by a combination of UNG, HAP1, DNA polymerase beta, and DNA ligase I. This is the first complete reconstitution of base excision repair using entirely eukaryotic proteins.

Antibodies↗

PubMed1999

DNA ligation during excision repair in yeast cell-free extracts is specifically catalyzed by the CDC9 gene product.

Excision repair of DNA is an important cellular response to DNA damage induced by radiation and many chemicals. In eukaryotes, base excision repair (BER) and nucleotide excision repair (NER) are two major excision repair pathways which are completed by a DNA ligation step. Using a cell-free system, we have determined the DNA ligase requirement during BER and NER of the yeast S. cerevisiae. Under nonpermissive conditions in extracts of the cdc9-2 temperature-sensitive mutant, DNA ligation in both BER and NER pathways was defective, and the repair patches were enlarged. At the permissive temperature (23 degrees C), DNA ligation during excision repair was only partially functional in the mutant extracts. In contrast, deleting the DNA ligase IV gene did not affect DNA ligation of BER or NER. Defective DNA ligation of BER and NER in cdc9-2 mutant extracts was complemented in vitro by purified yeast Cdc9 protein, but not by DNA ligase IV even when overexpressed. These results demonstrate that the ligation step of excision repair in yeast cell-free extracts is catalyzed specifically by the Cdc9 protein, the homologue of mammalian DNA ligase I.

Catalysis↗

PubMed2000

Novel substrates of Escherichia coli nth protein and its kinetics for excision of modified bases from DNA damaged by free radicals.

Escherichia coli Nth protein (endonuclease III) is a DNA glycosylase with a broad substrate specificity for pyrimidine derivatives. We discovered novel substrates of E. coli Nth protein using gas chromatography/isotope-dilution mass spectrometry and DNA samples, which were damaged by gamma-irradiation or by H(2)O(2)/Fe(III)-EDTA/ascorbic acid. These were 4, 6-diamino-5-formamidopyrimidine, 5,6-dihydroxyuracil, and 5, 6-dihydroxycytosine. The first compound was recognized for the first time as a purine-derived substrate of the enzyme. We also investigated kinetics of excision of a multitude of modified bases from three damaged DNA substrates. Excision of modified bases was determined as a function of enzyme concentration, incubation time, and substrate concentration. Excision followed Michaelis-Menten kinetics. Kinetic parameters were determined for the following modified bases: 4,6-diamino-5-formamidopyrimidine, cis- and trans-thymine glycols, 5-hydroxycytosine, cis- and trans-uracil glycols, 5-hydroxyuracil, 5-hydroxy-5-methylhydantoin, alloxan, 5, 6-dihydroxycytosine, 5,6-dihydroxyuracil, 5-hydroxy-6-hydrothymine, and 5-hydroxy-6-hydrouracil. The results show that three newly discovered substrates were excised by the enzyme with a preference similar to excision of its known major substrates such as thymine glycol and 5-hydroxycytosine. Excision kinetics significantly depended on the nature of the damaged DNA substrates in agreement with previous results on other DNA glycosylases. Specificity constants (k(cat)/K(M)) of E. coli Nth protein were compared to those of its previously investigated functional homologues such as human and Schizosaccharomyces pombe Nth proteins and Saccharomyces cerevisiae Ntg1 and Ntg2 proteins. This comparison shows that significant differences exist with respect to substrate specificity and kinetic parameters despite extensive structural conservation among the Nth homologues.

Bacterial Proteins↗

PubMed1975

Changes in host immunity following excision of a murine melanoma.

Changes in cell mediated and humoral immunity following the excision of a transplantable melanoma growing in the footpad of its syngeneic host, as measured by an in vitro cytotoxicity test, were assessed. Spleen cell cytotoxicity did not change significantly. Cells from the regional lymph nodes stimulated tumour growth before tumour excision. Three days following tumour excision this stimulatory effect was undetectable. Loss of serum factors capable of blocking the cytotoxicity of spleen cells occurred 24 h after tumour excision. Serum cytotoxicity increased after tumour excision to a maximum of the third day. Following tumour excision the rise in serum cytotoxicity and loss of regional lymph node tumour stimulation were concomitant with the loss of blocking activity.

Animals↗

PubMed1998

The importance of complete excision in the prevention of local recurrence of ductal carcinoma in situ.

Mastectomy probably represents over-treatment for the majority of women with screen detected ductal carcinoma in situ (DCIS) and breast-conserving surgery is now widely advocated. In this study, biopsy cavity shavings were used to ensure complete excision in 129 women undergoing breast-conserving surgery for screen detected DCIS. A margin was considered clear if DCIS was > 1 mm from any margin of excision and shavings were clear. Patients with involved margins (DCIS at resection margin) underwent re-excision, irrespective of shaving status. After re-excision, 101 women (78%) had clear margins and 28 (22%) close margins (DCIS < or = 1 mm from resection margin). Cavity shavings were histologically clear of DCIS in all cases. Ipsilateral DCIS recurrence occurred in 12 (9.3%) patients. Two recurrences also contained invasive carcinoma. The median time to diagnosis was 14 months and all recurrences occurred at the site of the previous biopsy. Seven recurrences were detected at the first annual mammogram, four at the second and one at the third. Ipsilateral recurrence was related to margin status; only 2 out of 101 (2%) patients with clear margins recurred, compared with 10 out of 28 (36%) patients with close margins. Local recurrence and close margin status both correlated with a high modified Van Nuys prognostic index score. Our results indicate that local relapse represents residual DCIS rather than true recurrence in the majority of cases. Cavity shavings have proved ineffective in ensuring complete excision. We now ensure a minimum 10 mm margin of excision around all screen-detected DCIS lesions.

Adult↗

PubMed2001

Pterygium excision and conjunctival mini-autograft: preliminary report.

PURPOSE: Pterygium excision is often followed by recurrence that may be more severe than the initial lesion. This study evaluated the efficacy of conjunctival mini-autograft following surgical excision of pterygium. METHODS: Eight patients underwent pterygium excision with a conjunctival mini-autograft. All patients had decreased visual acuity secondary to involvement of the central cornea by the pterygium. Following the excision, dissection of a conjunctival mini-autograft was performed. The mini-autograft was then transposed to the area of excision and secured in place with interrupted Vicryl and a few nylon sutures. Follow-up periods ranged from 5 to 9 years. RESULTS: All eyes healed with no post-operative complications and no recurrences of the pterygium in any patient up to a maximum follow-up period of 9 years 10 months. CONCLUSION: Conjunctival mini-autograft with excision of the pterygium is an effective procedure for the surgical management of pterygium.

Aged↗

PubMed2000

Bladder and sexual dysfunction after mesorectal excision for rectal cancer.

BACKGROUND: Urinary and sexual dysfunction are recognized complications of rectal excision for cancer. The aim of this study was to examine the frequency of such complications after mesorectal excision, shortly after this method was introduced. METHODS: Spontaneous flowmetry, residual volume of urine measurement and urodynamic examination, including cystometry and simultaneous detrusor pressure and urinary flow recording, was carried out before and 3 months after curative rectal excision. Urinary symptoms and sexual function were evaluated by means of questionnaires before and after operation. Each patient served as his or her own control. RESULTS: Forty-nine consecutive patients, 39 of whom had a total mesorectal excision (TME) and ten a partial mesorectal excision, were examined before surgery and 35 again after operation. In two patients, a weak detrusor was detected before operation. Two patients developed signs of bladder denervation after operation. Transitory moderate urinary incontinence appeared in four other women. Six of 24 men reported some reduction in erectile function and one became impotent. Two men reported retrograde ejaculation. All the complications were seen in the TME group. CONCLUSION: Mesorectal excision for rectal cancer resulted in a low frequency of serious bladder and sexual dysfunction.

Adult↗

PubMed1999

Regulation of excision of the conjugative transposon Tn916.

Excision from the donor DNA molecule is the first step in conjugative transposition of Tn916 and is followed by circularization of the transposon and its transfer to a new host. We have demonstrated that, in Gram-positive hosts, the Xis protein, as well as the site-specific recombinase Int, is required for the excision of Tn916. Using assays for closure of the excised covalently closed transposon and for repair of the donor DNA molecule, we found that neither protein alone is rate limiting for excision, but overexpression of Int and Xis together results in increased excision. After excision, the frequency of Tn916 circle formation was found to be the same as the frequency of repair of the donor DNA molecule. This suggests that a single reaction results in the closure of both molecules. We have also identified two transcripts that encode Int, one of which also encodes Xis and one of which does not, suggesting that there are steps in conjugative transposition of Tn916 that require Int without Xis.

Bacillus subtilis↗

PubMed2000

Cosmetic results of cryosurgery versus surgical excision for primary uncomplicated basal cell carcinomas of the head and neck.

BACKGROUND: The incidence of multiple facial basal cell carcinomas (BCCs) is increasing. OBJECTIVE: Comparison of cosmetic results after cryosurgery and excision for primary BCCs. METHODS: Cosmetic results after cryosurgery and excision (prospective randomized study) of primary BCCs in the head/neck area were assessed by five independent professional observers and by the patients. RESULTS: Ninety-six BCCs were treated either with surgical excision (n = 48) or cryosurgery (n = 48). Clinical professionals evaluated the cosmetic results after surgery as significantly better. The beautician had no preference for either therapy. The patient had a significant preference for excision. Localization and size of the tumor did not modify this general preference for excision. The male dermatologist, however, had a tendency to evaluate results in the cheek, periauricular, and neck area as inferior to those in the rest of the face, regardless of which therapy was given. CONCLUSION: In general, cosmetic results after excision are better than after cryosurgery.

Adolescent↗