324 research outputs found
Physiology and plant pathology
The impact of physical sciences, particularly biochemistry, has played a significant role in understanding etiology and syndrome in pathogenesis. Critical tissue respiration and enzyme changes, deranged carbohydrate and nitrogen metabolism, transpiratory disturbances and ionic imbalance produced by fungal toxins, exaggerated auxin relationships, formation of abnormal metabolite (s) (phytoalexins) have all contributed to a better understanding of the 'sick' plant. Plant virologists have made phenomenal progress in the applied field of the biochemistry of the infected plant and some of the recent researches on the nature of viruses and control measures adopted are worth emulating in other fields of plant pathology. A new field is developing round environment and disease proneness. This has reference to the rice blast disease where low nyctotemperatures for a long enough period makes for alterations in the nitrogen metabolism of the host and is governed by the balance between primary nitrogen metabolism and secondary metabolic events leading to synthesis of structural metabolites
Spectrochemical studies on the uptake of ions by plants I. The Lundegardh flame technique of ash analysis of toxin/antibiotic invaded cotton plants
Spectrochemical analysis, using the standard Lundegardh flame emission (spark-in-flame) method, of cotton plants infected by Fusarium vasinfectum Atk., showed an increased uptake of Mg, Ca, Fe and Mn with decreased accumulation of K over the healthy plants. It is suggested that the derangement in the selective absorption of ions, seen in the infected plants, is more likely to have been caused by chemical agents (toxins) than physical causes such as plugging of vessels
Inability ofExserohilum turcicum (Pass.) Leo. et Sug., to survive as a saprophyte in soilin situ
Flow pumping system for physiological waveforms
A pulsatile flow pumping system is developed to replicate flow waveforms with reasonable accuracy for experiments simulating physiological blood flows at numerous points in the body. The system divides the task of flow waveform generation between two pumps: a gear pump generates the mean component and a piston pump generates the oscillatory component. The system is driven by two programmable servo controllers. The frequency response of the system is used to characterize its operation. The system has been successfully tested in vascular flow experiments where sinusoidal, carotid, and coronary flow waveforms are replicated
A phase II study of the bispecific antibody MDX-H210 (anti-HER2 × CD64) with GM-CSF in HER2+ advanced prostate cancer
The proto-oncogene HER2 presents a novel therapeutic target. We report results in 25 patients with HER2+ advanced prostate cancer treated with the bispecific antibody MDX-H210 15 μg m−2by intravenous infusion plus GM-CSF 5 μg kg−1day−1by subcutaneous injection for 4 days repeated weekly for 6 weeks. Patients with stable disease or better received further cycles of treatment until disease progression or study withdrawal. 1 patient received no treatment and 4 received less than 1 cycle and are included in the toxicity analysis only. Median duration of follow up was 105+ (range 21–188) days. Toxicity was generally NCI-CTG 0–2. There were 2 grade 4 adverse events (heart failure and dyspnoea) and 1 grade 3 event (allergic reaction) resulting in discontinuation of the study medication. There were 9 further grade 3 events not resulting in trial withdrawal. There were no treatment-related deaths. 7/20 (35%) evaluable patients had a >50% PSA response of median duration 128 (range 71–184+) days. 7/12 (58%) patients with evaluable pain had improvements in pain scores. The PSA relative velocity on therapy decreased in 15/18 (83%) assessable patients compared to pre-study. GM-CSF and MDX-H210 is active in hormone refractory prostate carcinoma with acceptable toxicity; further studies are warranted. © 2001 Cancer Research Campaign http://www.bjcancer.co
Biosynthesis of HLA-C heavy chains in melanoma cells with multiple defects in the expression of HLA-A, -B, -C molecules
Recent investigations have shown that malignant transformation may down-regulate the expression of class I HLA molecules, beta(2)-microglobulin (beta(2)m) and members of the antigen-processing machinery. In the present study, we HLA-genotyped and identified at a biochemical level the three (HLA-A25, -B8, -Cw7) class I alleles expressed by the previously described [D'Urso CM et al (1992) J Clin Invest 87: 284-292] beta(2)m-defective human melanoma FO-1 cell line and tested their ability to interact with calnexin, calreticulin and the TAP (transporter associated with antigen processing) complex. Ail these alleles were found to bind calnexin, but not calreticulin or the poorly expressed TAP complex, both in parental and beta(2)m-transfected FO-1 cells, demonstrating a complex defect of class I expression in FO-1 cells. In these conditions, Cw7 heavy chains interacted with calnexin more strongly than A25 and B8, and preferentially accumulated in the endoplasmic reticulum, in both a calnexin-associated and a calnexin-free form. In addition, they could be transported to the cell surface at low levels even in the absence of beta(2)m, without undergoing terminal glycosylation. These results establish a parallel between HLA-C and the murine D-b and L-d molecules which have been found to be surface expressed and functional in beta(2)m-defective cells. They also demonstrate distinctive features of HLA-C molecules. We propose that the accumulation of several assembly intermediates of HLA-C might favour the binding of peptide antigens not readily bound by HLA-A and -B molecules in neoplastic cells with suboptimal class I expression
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