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Biomedical subjects

J Poland

Publications and source records attributed to J Poland.

16 recordsLinked to original sources
PubMed2001

Characterization of the differential protein expression associated with thermoresistance in human gastric carcinoma cell lines.

Resistance to chemotherapeutic agents is one of the major problems faced during palliative therapy of tumor cells. Thus, chemotherapy is frequently combined with other modes of therapy such as radiation therapy and/or hyperthermia. Tumor cells respond to heat stress with development of thermotolerance and the interactions between chemo- and thermoresistance phenomena are not clearly understood. In this paper, we analyze the differential protein expression in vitro in human stomach cancer cells, their chemoresistant and thermoresistant counterparts using proteomics. The immediate aim was to identify sets of proteins that may lead to the development of thermoresistance. Based on these results, we aim to develop functional tests and methods for the modulation of thermoresistance and chemoresistance phenomena that may assist the therapy of inoperable cancers.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

A new silver staining apparatus and procedure for matrix-assisted laser desorption/ionization-time of flight analysis of proteins after two-dimensional electrophoresis.

We report on a new silver stain especially developed for staining large gels (25 cm x 20 cm) from the Hoefer ISO-DALT system for matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis of proteins. The staining protocol can be summarized as follows: the gels are sensitised in tetrathionate/potassium acetate solution and washed several times in distilled water. After impregnation with silver nitrate, the silver is reduced in the presence of potassium carbonate, thiosulphate and formaldehyde. The staining procedure is stopped with Tris/acetate after which the gels are rinsed and stored in water before spot picking for MALDI-TOF analysis is performed. This protocol has several advantages over existing ones. The gels are stained in a new apparatus that reduces gel handling to a minimum thus also reducing the contamination with keratins to a minimum. The development times in potassium carbonate are very long (up to 40 min) thus improving batch-to-batch reproducibility. Only the surface of the proteins is stained and the silver can be oxidized, thereafter MALDI-TOF can be performed with protein loads as little as 100 micrograms per gel.

Cell Line↗
PubMed1993

Regression of oral leukoplakia with alpha-tocopherol: a community clinical oncology program chemoprevention study.

BACKGROUND: Oral leukoplakia is an important model for developing chemoprevention approaches for lesions in the upper aerodigestive tract. These lesions most often result from exposure to carcinogens such as tobacco and alcohol and may precede development of invasive cancer. The potent antioxidant alpha-tocopherol (vitamin E) has prevented the development of cancers of the oral cavities in animal models. PURPOSE: The objectives of this study were to evaluate the toxicity and efficacy of alpha-tocopherol in patients with oral leukoplakia and to assess the feasibility of performing chemoprevention trials through the network of the Community Clinical Oncology Program (CCOP). METHODS: A single-arm phase II study using the nontoxic agent alpha-tocopherol to treat oral premalignant leukoplakia was performed at seven institutions affiliated with the CCOP through The University of Texas M. D. Anderson Cancer Center. Patients with symptomatic leukoplakia or dysplasia were treated orally with alpha-tocopherol (400 IU) twice daily for 24 weeks. Follow-up was performed at 6, 12, and 24 weeks after the start of treatment to assess toxicity and response, and serum alpha-tocopherol levels were determined at baseline and at 6 and 24 weeks. RESULTS: Of the 43 patients who have completed 24 weeks of treatment, 20 (46%) had clinical responses and nine (21%) had histologic responses. Mean serum alpha-tocopherol levels were 16.1 micrograms/mL at baseline and increased to 34.29 micrograms/mL after 24 weeks of treatment. Patient-recorded drug calendars, as well as serum drug levels, indicated excellent patient compliance; an average of 95% of the prescribed pills were taken. Treatment was extremely well tolerated; no grade 3 or 4 toxic effects were reported. CONCLUSIONS: Administration of alpha-tocopherol resulted in both clinical and histologic responses in premalignant leukoplakia lesions. The study also demonstrated that chemoprevention trials can be performed through the CCOP. The major problems were that a high percentage of patients were not assessable for response, some patients withdrew because expenses were not reimbursable, and there was limited participation within the CCOP network. These problems may reflect difficulties inherent in the implementation of multi-institutional chemoprevention trials. IMPLICATIONS: The efficacy of alpha-tocopherol alone and in combination with other chemopreventive agents for carcinogenesis in the upper aerodigestive tract should be explored in future trials.

Alcohol Drinking↗
PubMed1991

Prevention and treatment of oral complications in the cancer patient.

The mouth and throat are vulnerable sites in cancer patients, subject to treatment-related stomatitis and mucositis, and infection due to bacteria, viruses, and fungi. The author presents a summary of the conditions and their causes, and an update on current treatments of choice.

Adult↗
PubMed1985

Nineteen cases of plague in Arizona. A spectrum including ecthyma gangrenosum due to plague and plague in pregnancy.

We review the cases of 19 successfully treated plague patients, with emphasis on the clinical and epidemiologic features of the disease. Proper staining and culturing of bubo aspirates; prompt institution of streptomycin, chloramphenicol or tetracycline therapy in presumptive cases, and supportive care are the crucial factors in the treatment of plague. This disease should be considered in patients in a toxic condition who have lymphadenitis, pneumonia or septic shock and who have been in endemic areas within the past ten days.

Adolescent↗
PubMed1984

Methionine and glutamine transport systems in D-methionine utilising revertants of Salmonella typhimurium.

In Salmonella typhimurium, methionine auxotrophs such as metB can use D-methionine as a methionine source. MetP mutations prevent this growth since D-methionine can enter only via the metP high-affinity methionine transport system. D-methionine utilising revertants ( Dmu +) were selected from metB23 metP760 ( HU76 ) following nitrosoguanidine mutagenesis. The properties of two such revertants, HU206 and HU415 , indicated that reversion was not due to backmutation of the metP760 mutation. Genetic analysis indicated that each strain possessed two mutations, designated dmu and gln, in addition to the original metB23 and metP760 mutations. The dmu mutation restores ability to grow on D-methionine, partly restores D- and L-methionine transport activity, and makes the cells particularly sensitive to inhibition by L-glutamine while growing on D but not L-methionine. The growth inhibition by L-glutamine was shown to be caused by competition by L-glutamine for D-methionine transport by the high-affinity methionine system. The gln mutation greatly reduces activity of the high-affinity glutamine transport system. The Dmu + strains are also partly defective in the glutamine low-affinity transport system, possibly because the partially-restored methionine high-affinity system, or a component of tis system, functions in the transport of glutamine by its low-affinity system.

Biological Transport, Active↗
PubMed1978

Sensitivity of mycoplasmas of the respiratory tract of pigs and horses to erythromycin and its use in selective media.

The ability of erythromycin in liquid medium to suppress the growth of eight species of acholeplasma and of 13 species of mycoplasma was tested. The Acholeplasma spp and two glycolytic Mycoplasma spp from horses--a slow glucose-metabolising (SGM) mycoplasma and a strain N3, related to M mycoides--were sensitive to erythromycin. Thus the growth of acholeplasmas can be suppressed when attempts are made to isolate pathogens from the porcine respiratory tract, but, in the case of horses, erythromycin would suppress not only Acholeplasma spp but also two Mycoplasma spp of unknown pathogenicity in the equine respiratory tract.

Acholeplasma↗
PubMed1971

The production of pneumonia with or without pleurisy in gnotobiotic piglets with pure cultures of strain TR 32 of Mycoplasma hyorhinis.

Nine gnotobiotic piglets, when 8-9 days old, were exposed to an aerosol of strain TR32 of Mycoplasma hyorhinis and killed at intervals from 14 to 37 days after infection. The aerosol of M. hyorhinis caused bronchopneumonia in 1 pig, pleurisy alone in 2 pigs, pleuropneumonia in 2 pigs and no lung changes in 4 pigs. M. hyorhinis was re-isolated from the lungs of all infected pigs, irrespective of the presence or absence of lesions, though it was only isolated from the serosa and joints when lesions were present. Four control pigs exposed to aerosols of mycoplasma medium had no lesions.

Animals↗
PubMedDate not supplied

Glucose, insulin, potassium protection during the course of hypothermic global ischemia and reperfusion: a new proposed mechanism by the scavenging of free radicals.

Glucose, insulin, potassium (GIK: 300 g glucose + 50 U insulin + 80 mEq KC1/L) was administered to anesthetized dogs as a 30-ml bolus followed by 1.5 ml/kg/h for 2 h. Five populations were studied: control (C, n = 6); 60 min hypothermic arrest both without (I, n = 6) and with pretreatment (I + GIK, n = 6); 60 min hypothermic arrest followed by reperfusion without (R, n = 6) and with pretreatment (R + GIK, n = 6). Glycogen content declined during the ischemic and reperfusion periods whether or not GIK pretreatment was utilized. Glycogen values did not differ significantly among the four groups. GIK pretreatment significantly protected sarcoplasmic reticulum (SR) calcium uptake rates. SR Ca2+ + Mg2+ adenosine triphosphatase (ATPase) activity was unaffected in the I group, depressed in the R group, but protected by GIK pretreatment. Myofibrillar pCa-ATPase activity was significantly depressed in the I group and unaffected by GIK pretreatment. In the R + GIK group, myofibrillar pCa-ATPase activity was identical to controls at all calcium concentrations except for Vmax. In vitro, generation of the superoxide anion by a xanthine-xanthine oxidase system at pH 7.0 significantly depressed both SR calcium uptake and ATPase activity, and this depression was partially reversible by glucose. Generation of the hydroxyl free radical and pH 6.4 significantly depressed calcium uptake but not ATPase activity, and this depression was reversible with glucose + superoxide dismutase. GIK pretreatment exerts a protective effect on the excitation-contraction coupling system during hypothermic global ischemia and reperfusion. Glycogen augmentation after short-term GIK infusion was not significantly different. It is hypothesized that an additional mechanism by which GIK may protect subcellular function is by serving as a scavenger of free radicals generated during the ischemic/reperfusion process.

Adenosine Triphosphatases↗