Pyrimidine dimer formation in human skin.
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Biomedical subjects
Publications and source records attributed to J C Sutherland.
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Ninety-three stage III and IV patients with non-Hodgkin's lymphoma were randomized to either high dose CVP (cyclophosphamide 1500 mg/m2 i.v. day 1, vincristine 1.4 mg/m2 day 1, and prednisone 40 mg/m2 orally days 1-10) or high dose CAVP (cyclophosphamide 1000 mg/m2 i.v. day 1, doxorubicin 45 mg/m2 i.v. day 1, vincristine and prednisone as above). Overall, the complete response (CR) rates were similar (CVP 51%, CAVP 51%). Patients with the International Working Formulation diffuse large cell lymphoma had significantly higher CR with CAVP. No difference in CR duration was detected between the two regimens. CRs were durable with 68% of diffuse and 86% of diffuse large cell complete responders alive and disease free at 7 years. Survival was similar with both regimens except for patients with diffuse large cell lymphoma who survived longer with CAVP. Both regimens were equitoxic with neutropenia less than 1.0 x 10(9)/liter in 36% of courses, infections in 15% of courses, and fatal infections in three patients. These intermittent high dose cyclophosphamide equitoxic regimens produced durable responses. However, the doxorubicin-containing regimen is superior in diffuse large cell lymphoma.
Paranasal sinusitis occurred in 52 immunosuppressed cancer patients treated over 5 years at the University of Maryland Cancer Center. Twenty-one patients had aspergillus sinusitis; Aspergillus sp, including flavus and niger were directly recovered from sinus in 19 of the 21 infections. Two other patients with sinus involvement and positive nose cultures for Aspergillus flavus or fumigatus and microbiologically documented pulmonary aspergillosis were considered clinically, although not microbiologically, documented. Predisposing factors for aspergillus sinusitis during the 60 days prior to infection diagnosis were granulocyte count less than 500 microliter (mean duration, 42 days versus 14 days for sinusitis of other etiology; P less than 0.001), prolonged hospitalization (mean duration, 22 days versus 14 days for patients with nonfungal sinusitis; P less than 0.001), and prolonged antibiotic therapy (mean duration, 22 days versus 9 days; P less than 0.001). Treatment with amphotericin B was initially successful for 18 of 21 patients; however, 11 of 18 patients had infection recurrence that always developed at time of tumor exacerbation and reinstitution or intensification of chemotherapy. These findings suggest that aspergillus sinusitis in cancer patients is seen in association with prolonged neutropenia and antibiotic therapy, is amenable to therapy, but tends to recur with relapse of malignancy.
The time-resolved fluorescence properties of phenol and straight-chained phenol derivatives and tyrosine and simple tyrosine derivatives are reported for the pH range below neutrality. Phenol and straight-chained phenol derivatives exhibit single exponential fluorescence decay kinetics in this pH range unless they have a titratable carboxyl group. If a carboxyl group is present, the data follow a two-state, ground-state, Henderson-Hasselbalch relationship. Tyrosine and its derivatives with a free carboxyl group display complex fluorescence decay behavior as a function of pH. The complex kinetics cannot be fully explained by titration of a carboxyl group; other ground-state processes are evident, especially since tyrosine analogues with a blocked carboxyl group are also multiexponential. The fluorescence kinetics can be explained by a ground-state rotamer model. Comparison of the preexponential weighting factors (amplitudes) of the fluorescence decay constants with the 1H NMR determined phenol side-chain rotamer populations shows that tyrosine derivatives with a blocked or protonated carboxyl group have at least one rotamer exchanging more slowly than the radiative and nonradiative rates, and the fluorescence data are consistent with a slow-exchange model for all three rotamers, the shortest fluorescence decay constant is associated with a rotamer where the carbonyl group can contact the phenol ring, and in the tyrosine zwitterion, either rotamer interconversion is fast and an average lifetime is seen or rotamer interconversion is slow and the individual fluorescence decay constants are similar.
Steady-state and time-resolved fluorescence properties of the single tyrosyl residue in oxytocin and two oxytocin derivatives at pH 3 are presented. The decay kinetics of the tyrosyl residue are complex for each compound. By use of a linked-function analysis, the fluorescence kinetics can be explained by a ground-state rotamer model. The linked function assumes that the preexponential weighting factors (amplitudes) of the fluorescence decay constants have the same relative relationship as the 1H NMR determined phenol side-chain rotamer populations. According to this model, the static quenching of the oxytocin fluorescence can be attributed to an interaction between one specific rotamer population of the tyrosine ring and the internal disulfide bridge.
We have developed an alkaline agarose gel method for quantitating single strand breaks in nanogram quantities of nonradioactive DNA. After electrophoresis together with molecular length standards, the DNA is neutralized, stained with ethidium bromide, photographed, and the density profiles recorded with a computer controlled scanner. The median lengths, number average molecular lengths, and length average molecular lengths of the DNAs can be computed by using the mobilities of the molecular length standards. The frequency of single strand breaks can then be determined by comparison of the corresponding average molecular lengths of DNAs treated and not treated with single strand break-inducing agents (radiation, chemicals, or lesion-specific endonuclease). Single strand break yields (induced at pyrimidine dimer sites in uv-irradiated human fibroblasts DNA by the dimer-specific endonuclease from Micrococcus luteus) from our method agree with values obtained for the same DNAs from alkaline sucrose gradient analysis. The method has been used to determine pyrimidine dimer yields in DNA from biopsies of human skin irradiated in situ. It will be especially useful in determining the frequency of single strand breaks (or lesions convertible to single strand breaks by specific cleaving reagents or enzymes) in small quantities of DNA from cells or tissues not amenable to radioactive labeling.
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A reusable urinary collection device suitable for quantitative collection of uncontaminated urinary samples from rats without using a metabolism cage has been designed. The device can be attached to the pelvic skin within 5 min with minimum handling and discomfort to the unanesthetized rat using an adhesive. The suitability of this device was investigated by collecting and analyzing urine over a 48-h period following the intraperitoneal injection of [14C]inulin. A two-way crossover study was done with samples from one of the two experiments being collected while the animal was housed in a commercially available metabolism cage equipped to separate urine and feces. The percent of the dose excreted, food and water consumption, and the urinary output were not statistically different for rats housed in the metabolism cages or with the collection device attached. Histopathological examination of the rats revealed no pathology after a 24-h period except minor skin inflammation which occurred both in controls and animals to which the device was attached. These studies demonstrate the comparability of the new urine collection device to a commercially available metabolism cage in the quantitative collection of small (0-7 mL) urine samples with less contamination of the samples from the environment.
A two-dimensional scanner based on a digital plotter is described. The device is used to analyze photographic negatives of ethidium bromide-stained DNA-agarose gels. Scanning is controlled by and photometric data transferred to a computer for processing, storage, display, and analysis such as integration of the areas under bands and determination of the mean distances of migration of polydisperse samples. An integral light source and detector module designed for reading optical "bar-codes" is mounted in place of the pen of the plotter. Spatial resolution and reproducibility are about 0.2 and 0.005 mm, respectively. Photometric precision as good as one part per thousand is achieved by sinusoidal modulation of the intensity of the light source and synchronous, phase-sensitive detection of the signal from the detector by a lock-in amplifier. No part of the sensor assembly touches the surface of the negative. In contrast to a densitometer, the computer transforms photometric data to values directly proportional to the amount of DNA at given points on the original gel. The ability to move the sensor in two dimensions over the negative allows for the integration across the width of a lane correctly allowing for the nonuniform distribution of the DNA.
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V-79 Chinese hamster fibroblasts in monolayer culture were exposed to ultraviolet radiation at 313, 334, 365, 380, and 405 nm in the presence of either misonidazole or para-nitroacetophenone, drugs which act as both photosensitizers and radiosensitizers of cell killing. Survival was measured by a colony-forming assay. The resulting action spectra for cell death photosensitized by the drugs (the reciprocals of the exposures required at each wavelength to reduce cell survival to a given level) closely match their absorption spectra over a range of three orders of magnitude. These results demonstrate that cells can be killed upon excitation of misonidazole or para-nitroacetophenone in the absence of any other types of energy deposition or biomolecular damage.
A number of chemotherapeutic agents and multiple other drugs are known to produce interstitial pneumonitis and pulmonary fibrosis. It is important to realize which agents can produce or interact with other drugs to produce this complication. Two patients receiving combination chemotherapy with mitomycin-C and vinblastine developed diffuse interstitial pulmonary infiltrates in temporal relationship to vinblastine administration. The infiltrates cleared but recurred and produced chronic pulmonary changes. Since it is likely that the vinblastine either caused or contributed to the pulmonary damage, this drug must be considered among the antineoplastic agents which can cause or contribute to interstitial pulmonary disease.