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At least 19 recordsLinked to original sources
PubMed1979

Excisional biopsy and delayed wide excision versus primary wide excision of malignant melanoma.

In a retrospective study of 269 cutaneous malignant melanomas in stage I the influence of biopsy on survival was studied. Sixty patients were treated with primary wide excision and 209 patients with excisional biopsy followed by wide excision. The 5-year survival rates for the two groups were 75.0% and 82.8% respectively. There was an equal distribution of prognostic factors such as thickness, level of invasion, presence of ulceration, location and maximal size of the tumours in the two groups. As excisional biopsy with subsequent wide excision gives an accurate histopathologic diagnosis and permits a more rational treatment of thin melanomas, this form of treatment is recommended.

Biopsy↗
PubMed1975

The influence of caffeine on cell survival in excision-proficient and excision-deficient xeroderma pigmentosum and normal human cell strains following ultraviolet-light irradiation.

A uniform response to UV of four normal cell strains was demonstrated. One excision-proficient xeroderma pigmentosum variant strain (XP7TA) had a wild-type UV response but a second (XP30RO) was more sensitive. An excision-deficient xeroderma pigmentosum strain XP4L0 was substantially more sensitive than wild-type cell strains. A continuous post-irradiation treatment with non-toxic levels of caffeine enhanced the lethal effect of UV light in both xeroderma pigmentosum variant cell strains but not in cells from normal individuals. There was no detectable effect on cells from a xeroderma pigmentosum individual from complementation group A. These results correlate well with observations on the influence of caffeine on post-replication repair in the three classes of cells.

Caffeine↗
PubMed1979

Enhancement of excision-repair efficiency by conditioned medium from density-inhibited cultures in V79 Chinese hamster cells: evidence for excision repair as an error-free repair process.

Conditioned medium from density-inhibited V79 Chinese hamster cell cultures, given as a post-treatment to UV-irradiated homologous cells, was demonstrated to reduce the lethal action of ultraviolet light by temporarily blocking DNA replication. Since the increased survival was not affected by various non-toxic concentrations of caffeine, such protective effect would be attributable to the prolonged intervention of excision repair before DNA replication during the post-treatment period. The influence of conditioned medium on the UV-induced mutation at the ouabain-resistance locus was also examined and a significant decrease in mutation frequency was noted. The observed reduction in killing and mutation as a result of post-incubation in conditioned medium, which delays DNA replication, would be interpreted as evidence that conditioned medium provides a longer period of time for an error-free excision-repair process, leaving lesion in DNA available for error-prone post-replication repair.

Animals↗
PubMed1978

Excision repair of ultraviolet damage in mammalian cells. Evidence for two steps in the excision of pyrimidine dimers.

The incidence of pyrimidine dimer formation and the kinetics of DNA repair in African green monkey kidney CV-1 cells after ultraviolet (UV) irradiation were studied by measuring survival, T4 endonuclease V-sensitive sites, the fraction of pyrimidine dimers in acid-insoluble DNA as determined by thin layer chromatography (TLC), and repair replication. CV-1 cells exhibit a survival curve with extrapolation number n = 7.8 and Do = 2.5 J/m2. Pyrimidine dimers were lost from acid-insoluble DNA more slowly than endonuclease-sensitive sites were lost from or new bases were incorporated into high molecular weight DNA during the course of repair. Growth of CV-1 cultures in [3H]thymidine or X-irradiation (2 or 10 krads) 24 h before UV irradiation had no effect on repair replication induced by 25 J/m2 of UV. These results suggest that pyrimidine dimer excision measurements by TLC are probably unaffected by radiation from high levels of incorporated radionuclides. The endonuclease-sensitive site and TLC measurements can be reconciled by the assumption that pyrimidine dimers are excised from high molecular weight DNA in acid-insoluble oligonucleotides that are slowly degraded to acid-soluble fragments.

Cell Line↗
PubMed1979

The excision of N-methyl-N-nitrosourea-induced lesions from the DNA of Chinese hamster cells as measured by the loss of sites sensitive to an enzyme extract that excises 3-methylpurines but not O6-methylguanine.

An enzyme extract from Micrococcus luteus excises 3-methyladenine and 3-methylguanine but not O6-methylguanine, 7-methylguanine, 1-methyladenine or 7-methyladenine from DNA reacted with N-methyl-N-nitrosourea. The extract was used to detect lesions in the DNA of Chinese hamster cells treated in culture with N-methyl-N-nitrosourea. It was concluded that 3-methyladenine is excised from these cells with a half-life of about 2.3 h.

Animals↗
PubMedDate not supplied

Comparison of disk excision and combined disk excision and spinal fusion for lumbar disk ruptures.

In a series of private patients 77 per cent over-all satisfactory results were obtained from surgical disk excision performed without spinal fusion. Patients in whom spinal fusion combined with discectomy has been recommended by other authors are not much more satisfied than patients with discectomy alone without fusion (81% versus 74% satisfactory). Patients in whom the third party influence prevails were significantly more dissatisfied (only 59% satisfactory). Findings of a definite disk rupture at the time of surgery result in a higher incidence of satisfactory rating than those with degenerative changes or with normal findings.

Adolescent↗
PubMed1975

The excision of pyrimidine dimers from the DNA of mutant and wild-type strains of Ustilago.

UV-induced pyrimidine dimers were excised from the DNA of wild-type and four mutant strains of Ustilago maydis. Excision was partially dose dependent. The kinetics of excision differed in recombination deficient strains (rec 1 and rec 2) from those found in a recombination proficient radiation-sensitive strain (uvs 3). At fluences above 100 J-m-2 excision was saturated in uvs 3 but not in rec 1 or rec 2. Fluences above 300 J-m-2 started to saturate excision in wild-type. pol1-1, a temperature-sensitive DNA polymerase mutant, was excision proficient at both the permissive (22 degree) and restrictive (32 degree) temperatures. Wild-type cells were observed to excise CC before CT or TT in high dose experiments.

Basidiomycota↗
PubMed1979

Pyrimidine dimer excision in a Bacillus subtilis Uvr- mutant.

A technique which allows the measurement of small numbers of pyrimidine dimers in the deoxyribonucleic acid (DNA) of cells of Bacillus subtilis irradiated with ultraviolet light has been used to show that a strain mutant at the uvr-1 locus is able to excise pyrimidine dimers. Excision repair in this strain was slow, but incision may not be rate limiting because single-strand breaks in DNA accumulate under some conditions. Excision repair probably accounted for a liquid-holding recovery previously reported to occur in this strain. Recombinational exchange of pyrimidine dimers into newly replicated DNA was readily detected in uvr-1 cells, but this exchange did not account for more than a minor fraction of the dimers removed from parental DNA. Excision repair in the uvr-1 strain was inhibited by a drug which complexes DNA polymerase III with DNA gaps. This inhibition may be limited to a number of sites equal to the number of DNA polymerase III molecules, and it is inferred that large gaps are produced by excision of dimers. Because the uvr-1 mutation specifically interferes with excision of dimers at incision sites, it is concluded that the uvr-1 gene product may be an exonuclease which is essential for efficient dimer excision.

Bacillus subtilis↗
PubMed2026

Clinical outcomes of fusion vs excision in the treatment of painful type II accessory naviculars: A matched cohort study.

BACKGROUND: For painful Type II accessory naviculars, whether to remove or fuse them remains unclear based on the current literature. This study aimed to investigate the clinical outcomes of fusion versus excision in treating painful type II accessory naviculars. METHODS: This retrospective comparative study included and followed 54 eligible patients (from May 2017 to March 2023). After 1:1 propensity score matching (PSM), 34 patients (17 fusion versus 17 excision) were analyzed. Outcomes included Visual Analog Scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) midfoot score, Tegner score, complication rates, and radiographic measurements. Receiver operating characteristic (ROC) curve analysis was performed to identify the appropriate accessory navicular size cutoff for predicting nonunion following fusion. RESULTS: The mean follow-up was 35.0&#x202f;&#xb1;&#x202f;9.9 months. The fusion and excision groups showed significant and comparable VAS and AOFAS score improvements (p&#x202f;<&#x202f;.001). The fusion group had a higher complication rate (41.2% vs. 5.9%, p&#x202f;=&#x202f;.039), primarily nonunion and persistent pain. ROC curve analysis identified 50.3&#x202f;mm&#xb2; as the cutoff for nonunion risk; sizes <&#x202f;50.3&#x202f;mm&#xb2; predicted high nonunion likelihood. CONCLUSIONS: Both fusion and excision are effective treatments for painful type II accessory naviculars, demonstrating acceptable pain and functional improvement during midterm follow-up. However, the lower complication rate along with relatively superior functional recovery favors the excision technique. For accessory naviculars smaller than 50.3&#x202f;mm2, excision may be a better choice. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Humans↗
PubMed1975

A mutant of Eshcerchia coli K-12, URT-43, with a temperature-sensitive defect at the incision step of the excision repair mechanism.

URT-43, which has a defect in excision repair, exhibits a temperature-dependent ultraviolet survival. It was shown that URT-43 requires protein synthesis but not DNA synthesis for recovery, by examining recovery in a growth medium containing chloramphenicol or nalidixic acid. The recovery of irradiated bacteriophage lambda in URT-43 took place in a medium containing nalidixic acid at 30 degrees, but not at 41 degrees, and chloramphenicol prevented this recovery. These results seem to imply that the product of the mutated gene in URT-43 is labile. URT-43 was confirmed to have a temperature-sensitive mutation at the incision step of the excision repair mechanism by examining the nick formation of parental DNA in alkaline sucrose gradients. The release of pyrimidine dimers was reinvestigated directly by one- and two-dimensional paper-chromatography and indirectly by examining the distribution of DNA molecules synthesized after irradiation. Dimers were excised into the acid-soluble fraction when growing bacteria were incubated, but were not excised when in amino acid starved bacteria. These results suggest that URT-43 is a mutant slowly excising pyrimidine dimers because the product of a mutated gene concerned with the incision step of the excision repair mechanism is unstable.

Centrifugation, Zonal↗
PubMed1979

DNA excision-repair processes in human cells can eliminate the cytotoxic and mutagenic consequences of ultraviolet irradiation.

The ability of DNA excision-repair processes in diploid human fibroblasts to eliminate potentially cytotoxic and mutagenic lesions induced by UV radiation (254 nm) was demonstrated in two ways: (1) Cells with normal rates of excision were compared with cells with an intermediate rate of excision (XP2BE) and cells with an excision rate less than or equal to 1% that of normal (XP12BE) for sensitivity to the killing and mutagenic action of UV radiation. The normal cells proved resistant to doses of UV which reduced the survival of the XP cells to 14% and 0.7%, respectively, and increased the frequency of mutations to 8-azaguanine resistance in the XP cells 5- to 10-fold over background. (2) Cells in confluence were irradiated with cytotoxic and mutagenic doses of UV and allowed to carry out excision repair. After various lengths of time they were replated at lower densities to allow for expression of mutations to 6-thioguanine resistance and/or at cloning densities to assay survival. Normal cells and XP cells with reduced rates of excision repair (from complementation groups C and D) exhibited a gradual increase in survival from an initial level of 15--20% to 100% if held approximately 20 h in confluence. In contrast, XP12BE cells showed no increase from an initial survival of 20% even when held for 7 days. Normal cells irradiated in confluence but prevented from replicating for 7 days exhibited background mutation frequencies, whereas the mutation frequency in XP12BE cells did not change with the time in confluence.

Cell Line↗
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↗
PubMed1979

Recovery of DNA synthesis after ultraviolet irradiation of xeroderma pigmentosum cells depends on excision repair and is blocked by caffeine.

Normal human and xeroderma pigmentosum (XP, excision-defective group A) cells (both SV40-transformed) pulse-labeled with [(3)H]thymidine at various times after irradiation with ultraviolet light showed a decline and recovery of both the molecular weights of newly synthesized DNA and the rates of synthesis per cell. At the same ultraviolet dose, both molecular weights and rates of synthesis were inhibited more in XP than in normal cells. This indicates that excision repair plays a role in minimizing the inhibition of chain growth, possibly by excision of dimers ahead of the growing point. The ability to synthesize normal-sized DNA recovered more rapidly than rates of synthesis in normal cells, but both parameters recovered in phase in XP cells. During recovery in normal cells there are therefore fewer actively replicating clusters of replicons because the single-strand breaks involved in the excision of dimers inhibit replicon initiation. XP cells have few excision repair events and therefore fewer breaks to interfere with initiation, but chain growth is blocked by unexcised dimers. In both cell types recovery of the ability to synthesize normal-sized DNA was prevented by growing cells in caffeine after irradiation, possibly because of competition between the DNA binding properties of caffeine and replication proteins. Our observations imply that excision repair and semiconservative replication interact strongly in irradiated cells to produce a complex spectrum of changes in DNA replication which may be confused with parts of alternative systems such as post-replication repair.

Caffeine↗
PubMed1975

Clinical evaluation of the carbon dioxide laser for burn wound excisions: a comparison of the laser, scalpel, and electrocautery.

The use of a 100 watt carbon dioxide laser for surgical excisions of burn eschar was evaluated in 13 patients with symmetrical burns. In each patient, laser excision was compared with either scalpel or electrocautery excision of a comparable area. Graft "take," blood loss, and operative speed were measured. Graft "take" following laser excisions was comparable to that obtained when either scalpel or electrocautery was used. Regression analysis indicates that laser excisions involved 29% of the blood loss encountered with scalpel excisions and that laser speed was 1.49 times scalpel speed. Although laser blood loss was 60% of electrocautery blood loss, laser speed was significantly slower: 73% of electrocautery speed. These differences, however, were of small clinical consequence. It is felt that the surgical arm of this laser is at present quite awkward and is in need of technological refinement if the full potential of the laser is to be realized.

Burns↗