Biomedical subjects
Publications and source records attributed to G Wright.
Methods and results are described for a series of laser matricectomy cases in the toes, 23 partial matricectomies and 58 total matricectomies. A high incidence of nail recurrence was experienced, 48% for partial matricectomy and 50% for total matricectomy. After review of results, the laser method seemed to be less satisfactory than traditional surgical methods.
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The abortion law of England is set out and the recent case of C v S, which was an unsuccessful attempt to restrain an abortion by the unmarried father of the unborn child. Neither the father nor the unborn child has the locus standi to bring such an action. Legal personality and rights and duties with reference to the unborn child are investigated.
We have examined the capacity of a series of 6-substituted pyrimidine and 2-substituted purine derivatives to inhibit mammalian thymidine kinase and the thymidine kinases encoded by type 1 and type 2 herpes simplex viruses. Several N2-substituted guanine and deoxy guanosine derivatives displayed selective inhibitory activity against the HSV-1 and HSV-2 thymidine kinases by competing with the phosphorylation of thymidine, suggesting a possible novel pharmacological approach to herpes viruses infections.
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Cytological examination of the aspirate of fine-needle biopsy is becoming more widely accepted as a screening test for malignancy in thyroid nodules. However, it tends to be used in addition to, rather than instead of, more traditional methods. In this five-year prospective evaluation we performed fine-needle biopsy in 618 euthyroid patients with nodular thyroid enlargement, 86% of whom also underwent radionuclide scans and 55% of whom underwent ultrasound scans. In 19% of patients fine-needle biopsy yielded insufficient material for diagnosis, and in 14% of patients normal follicular cells were found (which indicated that the clinical lesion was not sampled). To date, a histological diagnosis has been obtained in 258 (42%) patients, 44 of whom had malignancies. The results of the radionuclide and ultrasound scans did not alter the odds in favour of the detection of malignancy. The cytological diagnosis of malignancy was falsely-positive in two patients and falsely-negative in four patients (three cases of which probably were sampling errors). If, in addition to overtly-malignant cells, atypical Hürthle cells and follicular neoplasms were considered to be potentially malignant, fine-needle biopsy alone had a sensitivity of 87% and a specificity of 72%. This good accuracy would be reduced by sampling failures, but a policy of operating on all patients with potentially-malignant cells, or on those in whom satisfactory aspirates could not be obtained, would yield high rates of the diagnosis of malignancy and would reduce the number of operations. Our data indicate that the most-appropriate method of screening thyroid nodules for malignancy is fine-needle biopsy without pertechnetate scanning or ultrasound examinations.
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17-Acetylaphidicolin was 10-fold weaker and two derivatives lacking hydroxyl groups at the 16 and 17 positions were 100-fold weaker than aphidicolin as inhibitors of DNA polymerase alpha from HeLa and Chinese hamster ovary cells. 17,18-Diacetyl, 3,17,18-triacetyl and 3-epi derivatives of aphidicolin were inactive. Active compounds were, like aphidicolin, competitive with dCTP and did not inhibit aphidicolin-resistant DNA polymerases.
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This paper describes a noise-reduction technique applicable to multiple-measurement systems. This method, known as measurement-dependent filtering (or MDF), can be used to advantage in a number of MRI applications. We present the general theory for one of these applications, material-canceled projection imaging. We discuss and show the results of MDF for material-canceled images as well as for heavily T2-weighted spin-echo images and computed T2 images. Significant improvements in SNR are demonstrated while spatial resolution is preserved.
The incidence of cell injury, embryo survival, and implantation following cryopreservation of zygotes and two- to five-cell embryos was studied in 100 patients in order to evaluate the effect of duration of storage. The incidence of individual cell survival was 58% regardless of the length of time kept in liquid nitrogen or the stage of the embryo at freezing. There were 104 of 208 (50%) thawed embryos that survived completely intact, and of those, 24 implanted successfully. Twenty-one (21%) patients had a clinical pregnancy; two of them miscarried Neither the survival of zygotes or cleaved embryos upon thawing nor the incidence of implantation was affected by the duration of cryostorage.
Fifty embryos, previously frozen at the zygote or 2- to 4-cell stage, were studied. Observers, who were unaware of the occurrence of pregnancy, assessed the morphologic features of these embryos by retrospectively analyzing videocinematographic recordings that were made shortly before replacement. Seven of 26 zygotes and 4 of 24 cleaved embryos implanted, with the incidence of implantation being analyzed in relation to 12 morphologic characteristics. Smooth surface of the blastomere's membranes was a statistically significant predictor of implantation for frozen-cleaved embryos, and variable zona pellucida thickness was the only parameter with predictive value for frozen zygotes. A highly significant difference was found between the implanting capacity of previously frozen-cleaved embryos and the number of abnormal morphologic characteristics. Three quarters of the thawed embryos had at least two abnormal characteristics, indicating that cryodamage was high. Major advantages of videocinematography are the absence of time constraints associated with observing live embryos, the ability to observe new morphologic parameters by freeze-frame and slow motion, and the permanent storage of embryonic data for quality control evaluation.
A series of N2-substituted guanine derivatives was screened against mammalian thymidine kinase and the thymidine kinase encoded by type I herpes simplex virus to examine their capacity to selectivity inhibit the viral enzyme. Several bases, nucleosides, and nucleotides displayed selective activity. The mechanism of action of the most potent derivative, N2-phenyl-2'-deoxyguanosine (PhdG) was studied in detail. PhdG (a) inhibited the viral enzyme competitively with respect to the substrates thymidine and deoxycytidine, (b) was completely resistant to phosphorylation, (c) displayed limited toxicity for the HeLa cell lines employed as hosts for viral infection, and (d) selectively inhibited viral thymidine kinase function in intact cultured cells. The results indicate that the PhdG drug prototype has potential as a selective anti-herpes agent and as a novel molecular probe of the structure and function of herpes simplex thymidine kinase.
Ascending aortic blood pressure and flow were successfully measured shortly after sternotomy in 16 patients undergoing coronary artery bypass graft surgery. Total haemodynamic power in the aorta was 953.9(444.7) mJ.s-1 (mean (SD], of which 11.65% was pulsatile. Quadrature components accounted for 50.8% of the pulsatile power. The mean (SD) term of the input impedance spectrum was 149.3(51.1) X 10(6) kg.m-4.s-1 and the characteristic impedance was 81.6(3.88) X 10(6) kg.m-4.s-1. Arterial pulsations are thought to be important for adequate tissue perfusion and the movement of tissue fluids and lymph. It is suggested that atheroma may increase the workload of the heart by diminishing the capacitative coupling between the aorta and the peripheral resistance vessels as well as pathological changes in other organs by impeding the lateral transmission of energy into the tissues.