Search PubMed⌕ Search

Biomedical subjects

K R Fox

Publications and source records attributed to K R Fox.

177 records · Page 10Linked to original sources
PubMed1981

Bilateral retinal detachment with giant tears.

A ten-year-old boy underwent simultaneous bilateral repair of giant tear retinal detachments. He underwent scleral buckling with silicone explants, encircling band placement, and drainage of subretinal fluid bilaterally. Additionally, the left eye underwent intravitreal injection of air through the pars plana and postoperative argon laser photocoagulation. Intraoperative transcleral cryopexy was applied in each eye. After six months, visual acuity is maintained at 20/80 and 20/60 with the retina flat in both eyes.

Air↗
PubMed1980

Binding of quinoline analogues of echinomycin to deoxyribonucleic acid. Role of the chromophores.

Two novel antibiotics were isolated, designated compounds 1QN and 2QN respectively, having quinoline rings in place of one or both of the quinoxaline chromophores of echinomycin. Each removes and reverses the supercoiling of closed circular duplex DNA from bacteriophage PM2 in the fashion characteristic of intercalating drugs. For compound 1QN, the unwinding angle at I0.01 is almost twice that of ethidium, whereas for compound 2QN the value is indistinguishable from that of ethidium. Binding of both analogues produced changes in the viscosity of sonicated rod-like DNA fragments corresponding to double the helix extension found with ethidium, a feature characteristic of bifunctional intercalation by quinoxaline antibiotics. These results suggest that both compounds 1QN and 2QN behave as bifunctional intercalators but that compound 2QN produces only half the helix unwinding seen with compound 1QN and the natural quinoxalines. Binding curves for the interaction of both analogues with a variety of synthetic and naturally occurring nucleic acids were determined by solvent-partition analysis. Values for compound 2QN were also obtained by a fluorimetric method and found to agree well with the solvent-partition measurements. Compound 1QN bound most tightly to Micrococcus lysodeikticus DNA and, like echinomycin, exhibited a broad preference for (G + C)-rich DNA species. For compound 2QN no marked (G + C) preference was indicated, and the tightest binding among the natural DNA species studied was found with DNA from Escherichia coli. The two analogues also displayed different patterns of specificity in their interaction with synthetic nucleic acids. Compound 2QN bound to poly(dA-dT) slightly more tightly than to poly-(dG-dC), whereas compound 1QN displayed a large (approx. 11-fold) preference in the opposite sense. There was evidence of co-operativity in the binding to poly(dA-dT). It may be concluded that the chromophore moieties play an active role in determining the capacity of quinomycin antibiotics to recognize and bind selectively to specific sequences in DNA.

Base Composition↗
PubMed1980

Interaction between synthetic analogues of quinoxaline antibiotics and nucleic acids: role of the disulphide cross-bridge and D-amino acid centres in des-N-tetramethyl-triostin A.

1 [Ala3, Ala7] TANDEM is an analogue of des-N-tetramethyl-triostin A (TANDEM) in which both L-Cys residues of the octapeptide ring are replaced by L-Ala; accordingly it lacks the disulphide cross-bridge which limits the conformational flexibility of TANDEM. 2 In [L-Ser1] TANDEM the configuration of one of the serine residues is inverted, altering the disposition of one of the quinoxaline chromophores with respect to the peptide ring. 3 Both compounds interact weakly but detectably with natural DNAs as judged by spectral shifts and increases in the thermal denaturation ('melting') temperature Tm. They also raise the Tm of poly rA . poly rU. 4 Binding isotherms determined by solvent partition analysis with [Ala3, Ala7] TANDEM yield association constants of about 10(3) M-1 for its interaction with natural DNAs. A Scatchard plot for binding to poly(dA-dT) determined by solvent partition and spectrophotometric methods shows marked evidence of cooperativity with an intrinsic association constant 1.9 x 10(4) M-1, 8.7 nucleotides per binding site, and cooperativity parameter 15. 5 Binding of [Ala3, Ala7] TANDEM to short rod-like fragments of poly(dA-dT) increases their contour length by almost the theoretical amount expected for an ideal process of bifunctional intercalation. 6 No effect of either compound on the winding of the DNA helix could be detected in sedimentation experiments with closed circular duplex PM2 DNA. 7 It is concluded that the cross-bridge of TANDEM greatly stabilizes its binding to DNA, most probably via entropic factors, but is not the only structural feature that influences its AT sequence-selectivity. The consequences of epimerising one of the D-Ser residues appear as disastrous as epimerising both. 8 The experimental details for the synthesis of [Ala3, Ala7] TANDEM and [L-Ser1] TANDEM are given in an appendix to this paper.

Amino Acids↗
PubMed1980

Coats' disease.

Explore the source record for details and available documents.

Adolescent↗
PubMed1979

Staphylococcal ophthalmia neonatorum and the staphylococcal scalded skin syndrome.

A 3-week-old infant had neonatal ophthalmia neonatorum, treated in a routine manner which rapidly developed into an advanced case of staphylococcal scalded skin syndrome. The infant had sudden onset of widespread erythematous and tender areas of skin with subsequent exfoliation of large surface areas. We emphasize the recognition of this syndrome and the understanding that it may rapidly become a serious consequence of staphylococcal ophthalmia neonatorum. We stress the need for initial microbiologic studies and early antibiotic therapy for ophthalmia neonatorum.

Anti-Bacterial Agents↗
PubMed1977

Inherited combined deficiency of factor V and factor VIII: report of a case with normal factor VIII antigen and ristocetin-induced platelet aggregation.

A patient with inherited combined deficiency of factor V and factor VIII is reported, who demonstrated normal levels of factor VIII antigen and plasma cofactor for ristocetin-induced platelet aggregation. The relationship of this condition to classical hemophilia and von Willebrand's disease is discussed. The data presented suggest that multiple loci on at least 2 chromosomes are necessary for the normal expression of factor VIII activity.

Adult↗
PubMedDate not supplied

Omental caking in Hodgkin's disease. Computed tomography findings.

Neoplastic infiltration of the greater omentum is most commonly caused by metastatic ovarian, gastric, colonic, or pancreatic carcinoma. Because the omentum lacks lymphoid elements, lymphomatous infiltration is uncommon. To date, omental involvement by lymphoma has been reported exclusively in patients with non-Hodgkin's lymphomas. In this report, the computed tomography findings of omental caking caused by Hodgkin's lymphoma are described. Although rare, both Hodgkin's and non-Hodgkin's lymphomas should be included in the differential diagnosis of omental caking.

Diagnosis, Differential↗
PubMedDate not supplied

Severe acute extrinsic airway compression by mediastinal tumor successfully managed with extracorporeal membrane oxygenation.

The successful use of femoral venoarterial extracorporeal membrane oxygenation to support an adult patient with extrinsic airway compression secondary to a large mediastinal tumor is presented. Extracorporeal membrane oxygenation was continued until a combination of chemotherapy and radiation therapy allowed sufficient tumor shrinkage to permit decannulation. This method should be considered and available before manipulation of the airway in similar patients.

Adult↗
PubMedDate not supplied

Concurrent chemotherapy and radiation for breast conservation treatment of early-stage breast cancer.

PURPOSE: The optimal sequencing of chemotherapy and radiation therapy in patients with early-stage breast cancer undergoing breast-conservation treatment remains controversial. The purpose of this study is to evaluate the outcome of patients treated with one specific sequence of concurrent chemoradiation followed by additional chemotherapy. METHODS: Between 1977 and 1992, 210 patients with stage I and II breast cancer underwent lumpectomy and axillary lymph node dissection followed by treatment with concurrent chemotherapy and radiation therapy, followed by further chemotherapy. Chemotherapy consisted of two 28-day cycles of CF (oral cyclophosphamide, 100 mg/m2 day 1 to 14, and intravenous 5-fluorouracil, 600 mg/m2 days 1 and 8) during radiation therapy, followed in general by six cycles of CMF (CF doses as above plus intravenous methotrexate 40 mg/m2 days 1 and 8) after the completion of radiation therapy. Fifty patients also received hormonal therapy, predominantly tamoxifen. One hundred ten patients had clinical T1 lesions, and 100 had T2 lesions. Fifty-three patients were pathologic N0, and 157 patients were pathologic N1 (123 patients had one to three positive nodes, and 34 patients had four or more positive nodes). Median follow-up for node-negative patients (5.2 years) is shorter than for node-positive patients (7.6 years). Therefore, outcome is reported at 5 and 10 years for node-positive patients but only at 5 years for node-negative patients. RESULTS: For node-positive patients, outcomes at 5 and 10 years, respectively, were 86% and 70% for overall survival, 78% and 67% for no evidence of disease survival, and 82% and 69% for freedom from distant metastases. For node-negative patients, outcomes at 5 years were 94% for overall survival, 94% for no evidence of disease survival, and 94% for freedom from distant metastases. Pathologic nodal status was predictive of outcome after treatment. Local failure in the treated breast was 5% at 5 years and 13% at 10 years for all patients. CONCLUSIONS: Concurrent CF with radiation therapy followed by six cycles of CMF after radiation therapy results in excellent survival, freedom from distant metastases, and local control for both node-negative and node-positive patients. This regimen of concurrent chemotherapy and radiation therapy is one option for sequencing, and it avoids the delays in administration of either modality that are associated with other sequencing regimens.

Adult↗