Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 208
Filter
Add more filters

Country/Region as subject
Publication year range
1.
Infection ; 44(3): 365-70, 2016 Jun.
Article in English | MEDLINE | ID: mdl-26498284

ABSTRACT

Because of global mobility and migration resulting in a growing diversity of the donor pool, the risk for donor-derived tuberculosis in solid organ transplant recipients becomes more and more relevant, even in countries with a low overall tuberculosis incidence. Here, we describe a case series of donor-derived tuberculosis in 2 of 3 solid organ transplant recipients and one medical staff member in Germany resulting in the death of one recipient. This case series highlights the relevance of this topic to clinicians. It advocates for a better communication between organ procurement organizations and transplant centers regarding donor information and transplant recipient outcome. Furthermore, it underpins the necessity for a standardized critical incident reporting system in the german transplant system to improve short- and long-term recipient's safety, health and survival.


Subject(s)
Organ Transplantation/adverse effects , Tissue Donors , Transplant Recipients , Transplants/microbiology , Tuberculosis , Aged , Antitubercular Agents/administration & dosage , Antitubercular Agents/therapeutic use , Female , Health Personnel , Humans , Male , Middle Aged , Tuberculosis/drug therapy , Tuberculosis/microbiology , Tuberculosis/transmission
2.
Anaesthesist ; 65(5): 363-5, 2016 May.
Article in English | MEDLINE | ID: mdl-27129535

ABSTRACT

We report aĀ case of aĀ 27-year-old anesthetist who acquired tuberculosis (TB) while performing general anesthesia in aĀ renal transplant (RTX) patient who had donor-derived contagious TB. The anesthetist developed pleural TB 6Ā months after exposure. Contact investigations (CIs) did not include health care workers (HCWs) of the Department of Anesthesiology, thereby missing the opportunity for the early diagnosis and treatment of TB. Genomic fingerprinting revealed identical Mycobacterium tuberculosis (MT) isolates in the anesthetist and in the RTX patient. The recipient had acquired disseminated TB from the harvested renal graft. The donor (liver and kidneys), aĀ 67-year-old immigrant, had died from brain death by cerebral herniation after a stroke. She had been treated for tuberculosis with a pneumectomy 40Ā years ago. Since that time, she had been suffering from latent tuberculous infection (TBI), but had been considered to have been cured.


Subject(s)
Infectious Disease Transmission, Patient-to-Professional , Kidney Transplantation/adverse effects , Tuberculosis, Pulmonary/etiology , Tuberculosis, Pulmonary/transmission , Adult , Aged , Anesthetists , Antibiotics, Antitubercular/therapeutic use , Female , Humans , Liver Transplantation/adverse effects , Mycobacterium tuberculosis , Tissue Donors , Tuberculosis, Pulmonary/therapy
3.
World J Surg ; 39(6): 1557-66, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25691214

ABSTRACT

BACKGROUND: Limited surgical procedures for benign cystic neoplasms and endocrine tumours of the pancreas have the potential advantage of pancreatic tissue sparing compared to standard oncological resections. METHODS: Searching PubMed/MedLine, Embase and Cochrane Library identified 86 full papers: 25 reporting on enucleation (EN), 38 on central pancreatectomy (CP) and 23 on duodenum-preserving total/partial pancreatic head resection (DPPHRt/p). The results are based on analysis of data of 838, 912 and 431 patients for EN, CP and DPPHRt/s, respectively. RESULTS: The indication for EN for cystic neoplasms and neuro-endocrine tumours to EN was 20.5 and 73 %; for CP 62.9 and 31 %; and for DPPHRt/p 69.6 and 10.2%, respectively. The estimated mean tumour sizes were in EN-group 2.4 cm, in CP-group 2.9 cm and in DPPHRt/p-group 3.1 cm (DPPHRt/p vs EN, p = 0.035). Postoperative severe complications developed after EN, CP and DPPHRt/p in 9.6, 16.8 and 11.5% of patients; pancreatic fistula in 36.7, 35.2 and 20.1%; and reoperation was required in 4.7, 6.5 and 1.8 %, respectively. Hospital mortality after EN was 0.95 %; after CP 0.72%; and after DPPHRt/p 0.49%. Compared to EN and CP, DPPHRt/p exhibited significant lower frequency of reoperation (p = 0.029, p < 0.001) and lower rate of fistula (p < 0.001; p = 0.001). CONCLUSION: EN, CP and DPPHRt/p applied for benign tumours are associated with low surgery-related early postoperative morbidity, a very low hospital mortality and the advantages of conservation of pancreatic functions. However, the level of evidence for EN and CP compared to standard oncological resections appears presently low. There is a high level of evidence from prospective controlled trials regarding the significant maintenance of exocrine and endocrine pancreatic functions after DPPHRt/p compared to pancreato-duodenectomy.


Subject(s)
Neoplasms, Cystic, Mucinous, and Serous/surgery , Neuroendocrine Tumors/surgery , Pancreatectomy/methods , Pancreatic Fistula/etiology , Pancreatic Neoplasms/surgery , Hospital Mortality , Humans , Neoplasms, Cystic, Mucinous, and Serous/pathology , Neuroendocrine Tumors/pathology , Organ Sparing Treatments/methods , Pancreatectomy/adverse effects , Pancreatic Neoplasms/pathology , Reoperation
4.
Br J Surg ; 100(7): 911-5, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23575528

ABSTRACT

BACKGROUND: Experimental studies and small anecdotal reports have documented the potential and feasibility of transgastric appendicectomy. This paper reports the results of the new technique in a selected group of patients. METHODS: From April 2010 transgastric appendicectomy was offered to all patients with acute appendicitis, but without generalized peritonitis or local contraindications. RESULTS: Of 111 eligible patients 15 agreed to undergo the transgastric operation. After conversion of the first case to laparoscopy because of severe inflammation and adhesions, the following 14 consecutive transgastric procedures were completed. Two patients with initial peritonitis required laparoscopic lavage 4 days after transgastric appendicectomy, but no leaks were detected at the appendiceal stump or stomach. CONCLUSION: These preliminary results have shown the feasibility of this innovative procedure. Additional studies, however, are required to demonstrate the specific advantages and disadvantages of this approach, and define its role in clinical surgery.


Subject(s)
Appendectomy/methods , Appendicitis/surgery , Gastroscopy/methods , Natural Orifice Endoscopic Surgery/methods , Acute Disease , Adolescent , Adult , Aged , Feasibility Studies , Female , Humans , Male , Middle Aged , Young Adult
5.
Nat Med ; 3(6): 621-4, 1997 Jun.
Article in English | MEDLINE | ID: mdl-9176487

ABSTRACT

A reliable, noninvasive method for monitoring patients with transitional cell carcinoma (TCC) of the bladder would be of great clinical benefit. Cystoscopy is currently the "gold standard," but it is invasive, expensive and uncomfortable for the patient. Recently, we demonstrated a novel approach for the detection of primary bladder cancer based on microsatellite analysis of urine DNA. To determine the feasibility of this technique for following-up patients with TCC, we tested serial urine samples from 21 patients who had been treated for bladder cancer with 20 polymorphic microsatellite markers in a blinded fashion. We detected recurrent lesions in 10 out of 11 patients and correctly predicted the existence of a neoplastic cell population in the urine of two patients, 4 and 6 months before cystoscopic evidence of the tumor. The assay was negative in 10 of 10 patients who had no evident cancer. Microsatellite analysis of urine sediment represents a novel and potentially powerful clinical tool for the detection of recurrent bladder cancer.


Subject(s)
Carcinoma, Transitional Cell/urine , Microsatellite Repeats , Neoplasm Recurrence, Local/diagnosis , Neoplasm Recurrence, Local/urine , Urinary Bladder Neoplasms/urine , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Male , Middle Aged , Neoplasm Recurrence, Local/genetics , Single-Blind Method , Urinary Bladder Neoplasms/genetics
6.
J Cell Biol ; 32(2): 401-14, 1967 Feb.
Article in English | MEDLINE | ID: mdl-10976231

ABSTRACT

Rabbits were immunized with diphtheria toxoid combined with complete Freund's adjuvant. Half of the animals were started on intramuscular injections of chloramphenicol 24 hr before the injection of the antigens. There was a general depression of protein synthesis in the immune system in the presence of chloramphenicol, but a greater effect on the synthesis of antibody than on the synthesis of proteins necessary for reproduction and maturation. In contrast to the finding of antibody in cells of the spleen and in the circulation of the control animals, those animals receiving chloramphenicol did not have measurable circulating antibody, and their spleens contained only a few cells with intracytoplasmic antibody late in the course of the experiment. Cytologically there was maturation of potential antibody-producing cells in the red pulp and nonfollicular white pulp of the spleen while the animals were receiving chloramphenicol. These cells developed more slowly, and were fewer and smaller than those of the control animals. They had numerous small, electron-opaque particles in their cytoplasm early in development. Ribosomes were synthesized, though fewer in number. The endoplasmic reticulum formed more slowly.


Subject(s)
Chloramphenicol/pharmacology , Plasma Cells/cytology , Plasma Cells/drug effects , Protein Synthesis Inhibitors/pharmacology , Animals , Cell Differentiation/drug effects , Cell Differentiation/immunology , Female , Immunoglobulin G/immunology , Male , Microscopy, Electron , Plasma Cells/ultrastructure , Rabbits , Spleen/cytology
7.
Science ; 176(4030): 52-4, 1972 Apr 07.
Article in English | MEDLINE | ID: mdl-5061575

ABSTRACT

Calcium activated skinned frog muscle fibers develop a large relative force at a sarcomere length of 1.0 micrometer. Since the normal myofilament lattice is perturbed at this length, regularity of the lattice does not appear to be an important factor in the contraction mechanism.


Subject(s)
Biomechanical Phenomena , Calcium/pharmacology , Muscle Contraction , Myofibrils/physiology , Animals , Anura , In Vitro Techniques , Muscle Contraction/drug effects , Myofibrils/drug effects
8.
Science ; 271(5249): 659-62, 1996 Feb 02.
Article in English | MEDLINE | ID: mdl-8571131

ABSTRACT

Microsatellite DNA markers have been widely used as a tool for the detection of loss of heterozygosity and genomic instability in primary tumors. In a blinded study, urine samples from 25 patients with suspicious bladder lesions that had been identified cystoscopically were analyzed by this molecular method and by conventional cytology. Microsatellite changes matching those in the tumor were detected in the urine sediment of 19 of the 20 patients (95 percent) who were diagnosed with bladder cancer, whereas urine cytology detected cancer cells in 9 of 18 (50 percent) of the samples. These results suggest that microsatellite analysis, which in principle can be performed at about one-third the cost of cytology, may be a useful addition to current screening methods for detecting bladder cancer.


Subject(s)
DNA, Neoplasm/urine , Microsatellite Repeats , Urinary Bladder Neoplasms/diagnosis , Adult , Aged , Aged, 80 and over , Chromosome Deletion , Chromosomes, Human, Pair 9 , DNA, Neoplasm/genetics , Female , Genetic Markers , Heterozygote , Humans , Male , Middle Aged , Neoplasm Staging , Pilot Projects , Polymerase Chain Reaction , Urinary Bladder Neoplasms/genetics , Urinary Bladder Neoplasms/pathology , Urinary Bladder Neoplasms/urine , Urine/cytology
9.
Epilepsy Behav ; 14(3): 459-64, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19130899

ABSTRACT

OBJECTIVE: Clinicians monitor cognitive effects of drugs primarily by asking patients to describe their side effects. We examined the relationship of subjective perception of cognition to mood and objective cognitive performance in healthy volunteers and neurological patients. METHODS: Three separate experiments used healthy adults treated with lamotrigine (LTG) and topiramate (TPM), adults with epilepsy on LTG or TPM, and patients with idiopathic Parkinson's disease. Correlations were calculated for change scores on and off drugs in the first two experiments and for the single assessment in Experiment 3. RESULTS: Across all three experiments, significant correlations were more frequent (chi(2)=259, P < or = 0.000) for mood versus subjective cognitive perception (59%) compared with subjective versus objective cognition (2%) and mood versus objective cognitive performance (2%). CONCLUSIONS: Subjective perception of cognitive effects is related more to mood than objective performance. Clinicians should be aware of this relationship when assessing patients' cognitive complaints.


Subject(s)
Affect/physiology , Anticonvulsants/pharmacology , Cognition/physiology , Epilepsies, Partial/psychology , Parkinson Disease/psychology , Psychomotor Performance/physiology , Self Concept , Adult , Affect/drug effects , Anticonvulsants/therapeutic use , Cognition/drug effects , Cross-Over Studies , Depression/psychology , Double-Blind Method , Epilepsies, Partial/drug therapy , Female , Fructose/analogs & derivatives , Fructose/pharmacology , Fructose/therapeutic use , Humans , Lamotrigine , Male , Neuropsychological Tests , Parkinson Disease/drug therapy , Psychomotor Performance/drug effects , Quality of Life , Topiramate , Triazines/pharmacology , Triazines/therapeutic use
11.
J Clin Invest ; 66(5): 1162-5, 1980 Nov.
Article in English | MEDLINE | ID: mdl-7430346

ABSTRACT

The effect of sequential methotrexate and 5-fluorouracil on the clonal growth of the human colon adenocarcinoma cell, HCT-8, and the hormone-dependent human breast carcinoma cell, 47-DN, was examined. In both cell lines, when 5-fluorouracil was given during the last 6 h of a 24 h methotrexate exposure period, there was marked synergistic inhibition of clonal growth. Shorter intervals or the reverse sequence of drugs were either additive or antagonistic. These results indicate the importance of the drug sequence and time interval between drug administration for optimal cytotoxicity in these human cell lines. This information suggests that the administration of methotrexate 18 h before 5-fluorouracil may have potential application in the design of clinical trials for these malignancies.


Subject(s)
Adenocarcinoma/drug therapy , Breast Neoplasms/drug therapy , Carcinoma/drug therapy , Colonic Neoplasms/drug therapy , Fluorouracil/therapeutic use , Methotrexate/therapeutic use , Cell Line , Drug Administration Schedule , Fluorouracil/administration & dosage , Humans , Methotrexate/administration & dosage
12.
J Natl Cancer Inst ; 91(23): 2028-32, 1999 Dec 01.
Article in English | MEDLINE | ID: mdl-10580028

ABSTRACT

BACKGROUND: Organ-confined renal malignancies can be cured in the majority of patients, whereas more extensive lesions have a poor prognosis. We sought to develop a noninvasive test for renal cancer detection based on a novel molecular approach. METHODS: Matched urine and serum DNA samples were obtained before surgery from 30 patients with clinically organ-confined solid renal masses (25 with malignant tumors and five with tumors of low malignant potential) and were subjected to microsatellite analysis. Serum samples and urine samples obtained from 16 individuals without clinical evidence of genitourinary malignancy served as controls. RESULTS: Nineteen (76%) of the 25 patients with malignant tumors were found to have one or more microsatellite DNA alterations in their urine specimen, and 15 (60%) were found to have alterations in their serum DNA by microsatellite analysis. In every case, the microsatellite changes in urine or serum were identical to those found in the primary tumor. Three of five patients with tumors of low malignant potential were found to have DNA alterations in their urine, but none displayed alterations in their serum. Moreover, microsatellite alterations were not identified in either the urine or the serum samples from normal control subjects and patients with hematuria due to nephrolithiasis (renal stones). CONCLUSION: These data suggest that microsatellite DNA analysis of urine specimens provides a potentially valuable tool for the early detection of resectable kidney cancer. Furthermore, microsatellite analysis of serum samples reveals evidence of circulating tumor-specific DNA in approximately half of these patients and may reflect the propensity of these tumors to spread to distant sites at an early stage.


Subject(s)
DNA/urine , Kidney Neoplasms/diagnosis , Kidney Neoplasms/genetics , Microsatellite Repeats , Aged , Blood Chemical Analysis , DNA/blood , Humans , Kidney Neoplasms/blood , Kidney Neoplasms/urine , Loss of Heterozygosity , Middle Aged , Sensitivity and Specificity , Urinalysis
13.
Cancer Res ; 55(22): 5213-6, 1995 Nov 15.
Article in English | MEDLINE | ID: mdl-7585577

ABSTRACT

Carcinoma in situ (CIS) of the urinary bladder is an aggressive lesion that frequently progresses to an invasive tumor, yet the underlying molecular changes in this lesion are largely unknown. In this study, we microdissected 31 cases of CIS and examined them for loss of heterozygosity (LOH) on 13 chromosomal arms. Twenty-nine microsatellite markers were chosen for this analysis based on their location in regions previously shown to be frequently lost in primary transitional cell carcinoma of the bladder. LOH of chromosome 9 was a frequent event in these samples, occurring in 77% of these lesions, with 19 of 31 cases showing deletion on the 9p arm (61%) and 17 of 28 cases displaying LOH on 9q (61%). Fine mapping at 9p21 demonstrated that CIS also displayed a high frequency of homozygous deletion surrounding the p16INK4A locus, like superficial papillary tumors, the other form of noninvasive lesion found in the bladder. However, loss of 14q (70%) was frequent in CIS yet extremely rare in papillary lesions (9%). Other chromosomal arms showing frequent LOH included 8p (65%), 17p (60%), 13q (56%), 11p (54%), and 4q (52%), whereas slightly lower frequencies of loss were observed for 11q (36%), 4p (32%), 3p (31%), 18q (29%), and 5q (20%). CIS lesions already possess many of the genetic alterations displayed by invasive transitional cell carcinomas, potentially accounting for the aggressive nature of these lesions.


Subject(s)
Carcinoma in Situ/genetics , Chromosome Deletion , Urinary Bladder Neoplasms/genetics , Alleles , Chromosomes, Human, Pair 9 , Humans
14.
Cancer Res ; 55(22): 5396-9, 1995 Nov 15.
Article in English | MEDLINE | ID: mdl-7585608

ABSTRACT

Accumulating evidence implicates the presence of putative tumor suppressor genes on human chromosome 4 that are potentially inactivated in the genesis of several different neoplasms. To accurately determine the frequency of allelic loss on both arms of human chromosome 4, we screened 282 fresh-frozen human bladder carcinomas for allelic loss. Loss of heterozygosity of at least one marker for chromosome 4 was identified in 129 tumors (45.7%). Fine mapping was accomplished using up to 15 polymorphic markers on the p arm and 19 markers on the q arm. We identified a 3-cM minimal area of loss on the p arm between microsatellite markers D4S1608 and D4S404 deleted in 82 tumors (29%). A total of 68 tumors (24%) targeted a 14-cM critical region identified on the distal q arm between markers D4S426 and D4S408. Loss of these two regions correlated with advanced stage and grade of the lesions. These data identify distinct regions of loss on chromosome 4 potentially involved in the late progression of bladder carcinoma.


Subject(s)
Chromosome Deletion , Chromosomes, Human, Pair 4 , Urinary Bladder Neoplasms/genetics , Chromosome Mapping , Humans
15.
Cancer Res ; 55(15): 3246-9, 1995 Aug 01.
Article in English | MEDLINE | ID: mdl-7614456

ABSTRACT

Two hundred eighty-five primary human carcinomas of the urinary bladder were examined for allelic loss on chromosome 14q. Seventeen highly polymorphic dinucleotide markers spanning the long arm of this acrocentric chromosome were selected for fine PCR-based mapping. Loss of heterozygosity for at least one marker was observed in 72 (25.3%) tumors. Thirty-four of these 72 tumors (47.2%) lost the entire long arm (monosomy), as suggested by loss of heterozygosity at all informative sites. Allelic loss on 14q occurred in all grades and stages of bladder cancer but was more commonly associated with muscle-invasive tumors (Ta, 9.4%; T1, 24.1%; and > or = T2, 41%). A deletion map of 16 primary tumors with partial losses delineated two minimal regions of loss. One region (approximately 2 cM) was bounded by markers D14S75 and D14S288 and the other (approximately 3 cM) by D14S51 and D14S267. Our results demonstrate that 14q loss is common in invasive bladder cancer and suggest that two potential suppressor loci at 14q12 and 14q32.1-32.2 may contribute to the genetic progression of this common cancer.


Subject(s)
Chromosome Mapping , Chromosomes, Human, Pair 14/genetics , Gene Deletion , Genes, Suppressor , Urinary Bladder Neoplasms/genetics , Humans
16.
Cancer Res ; 56(21): 5044-6, 1996 Nov 01.
Article in English | MEDLINE | ID: mdl-8895762

ABSTRACT

Collecting duct carcinoma (CDC) of the kidney is a rare malignant neoplasm of distal nephron origin. Previous studies of CDC have shown loss of heterozygosity on chromosomal arm 1q in 57% of the cases studied. To better characterize 1q loss in CDC, we performed high-density mapping of the entire long arm of chromosome 1 in 13 CDC tumor samples. We observed complete deletion of chromosomal arm 1q in 5 samples and partial deletion in 4 additional tumors. Our study further showed that the region of minimal deletion is located at 1q32.1-32.2. Sixty-nine percent (9 of 13) of the tumors showed loss of heterozygosity in this area. These data suggest that a gene or group of genes that contribute to the development of distal nephron tumors may be located within the 1q32.1-32.2 region.


Subject(s)
Chromosome Deletion , Chromosome Mapping , Chromosomes, Human, Pair 1 , Kidney Neoplasms/genetics , Kidney Tubules, Collecting , Humans
17.
Cancer Res ; 56(8): 1892-5, 1996 Apr 15.
Article in English | MEDLINE | ID: mdl-8620510

ABSTRACT

Tumors of varying malignant potential arise from the complex epithelial lining of the nephron. Although the molecular characteristics of renal clear cell carcinomas, which arise from the proximal tubule, have been studied, little is known about tumors that develop from other parts of the renal tubular system. To elucidate common molecular lesions that may contribute to the development or progression of nonproximal tubule renal tumors, we performed a detailed microsatellite allelotype of lesions thought to arise from the renal collecting duct. Eighteen collecting duct carcinomas (CDCs) and 13 renal oncocytomas were studied using highly informative microsatellite markers on all autosomal arms. Loss of heterozygosity (LOH) was identified on multiple chromosomal arms in CDCs and renal oncocytomas. Microsatellite analysis revealed LOH of 1q in 57% of informative CDCs. LOH was also observed on arms 6p (45%), 8p (40%), and 21q (40%). In renal oncocytomas, LOH of 1q occurred in approximately 30% of tumors, but 1p LOH was observed in 57% of informative cases analyzed. High levels of LOH were also observed on arms 8p, 14q, 19q, and 21q in the oncocytomas studied. Loss of chromosomal arm 3p was infrequent in both tumor types. Our results suggest that the molecular events that contribute to the development of distal nephron tumors are distinct from those associated with the etiology of proximal tubule renal cancers.


Subject(s)
Chromosome Deletion , Chromosomes, Human , DNA, Satellite/genetics , Kidney Neoplasms/genetics , Microsatellite Repeats/genetics , Adenoma, Oxyphilic/genetics , Alleles , Carcinoma/genetics , Chromosome Mapping , Chromosomes, Human, Pair 1 , Genetic Markers , Humans , Kidney Tubules, Collecting , Nephrons , Polymerase Chain Reaction
18.
Cancer Res ; 61(19): 7015-9, 2001 Oct 01.
Article in English | MEDLINE | ID: mdl-11585726

ABSTRACT

Mitochondrial DNA (mtDNA) mutations scattered through coding and noncoding regions have been reported in cancer. The mechanisms that generate such mutations and the importance of mtDNA mutations in tumor development are still not clear. Here we present the identification of a specific and highly polymorphic homopolymeric C stretch (D310), located within the displacement (D) loop, as a mutational hotspot in primary tumors. Twenty-two % of the 247 primary tumors analyzed harbored somatic deletions/insertions at this mononucleotide repeat. Moreover, these alterations were also present in head and neck preneoplastic lesions. We further characterized the D310 variants that appeared in the lung and head and neck tumors. Most of the somatic alterations found in tumors showed deletion/insertions of 1- or 2-bp generating D310 variants identical to constitutive polymorphisms described previously. Sequencing analysis of individual clones from lymphocytes revealed that patients with D310 mutations in the tumors had statistically significant higher levels of D310 heteroplasmy (more than one length variant) in the lymphocyte mtDNA as compared with the patients without D310 mutations in the tumor mtDNA. On the basis of our observations, we propose a model in which D310 alterations are already present in normal cells and achieve homoplasmy in the tumor through a restriction/amplification event attributable to random genetic drift and clonal expansion.


Subject(s)
DNA, Mitochondrial/genetics , Microsatellite Repeats/genetics , Neoplasms/genetics , Carcinoma, Squamous Cell/blood , Carcinoma, Squamous Cell/genetics , Female , Germ-Line Mutation , Head and Neck Neoplasms/blood , Head and Neck Neoplasms/genetics , Humans , Lung Neoplasms/genetics , Lymphocytes/physiology , Male , Neoplasms/blood , Polymorphism, Genetic , Precancerous Conditions/blood , Precancerous Conditions/genetics , Sequence Analysis, DNA
19.
Biochim Biophys Acta ; 1367(1-3): 127-33, 1998 Oct 05.
Article in English | MEDLINE | ID: mdl-9784622

ABSTRACT

The finding of Barnett et al. (Biophys. J. 61 (1992) 358) that NPM-reacted crossbridge heads do not bind strongly to actin in rigor solution is not easily interpreted in terms of the solution studies of Xie and Schoenberg (Biochemistry 37 (1998) 8048) who found strong binding of NPM-reacted myosin subfragment-1 to actin in solutions devoid of MgATP. For this reason, the current work uses stiffness measurement to re-investigate the binding of rabbit skeletal muscle crossbridges to actin in rigor solution. It is found that NPM-reacted crossbridge heads bind strongly to actin in rigor solution providing one is extremely careful to reduce MgATP contamination to levels well below those that would have a detectable effect on unmodified fibers. The reason for this is that NPM-reacted crossbridge heads, which hydrolyze MgATP extremely slowly, are especially susceptible to contaminant MgATP. The new fiber results show a strong correlation with the solution results. A further manifestation of this correlation is that pPDM-reacted crossbridge heads are different from NPM-reacted ones in that, like in solution, they remain weakly binding to actin even at extremely low MgATP levels. The findings suggest that the covalent crosslinking of SH1 and SH2 by pPDM is likely playing a significant role in locking pPDM-reacted crossbridge heads in a weakly binding conformation.


Subject(s)
Muscle, Skeletal/metabolism , Actins/chemistry , Actins/metabolism , Actins/physiology , Adenosine Triphosphate/metabolism , Animals , Binding Sites , Biomechanical Phenomena , Biophysical Phenomena , Biophysics , Cross-Linking Reagents , In Vitro Techniques , Maleimides , Muscle Contraction/physiology , Muscle, Skeletal/chemistry , Muscle, Skeletal/physiology , Myosin Subfragments/chemistry , Myosin Subfragments/metabolism , Myosin Subfragments/physiology , Rabbits
20.
Biochim Biophys Acta ; 1232(1-2): 13-20, 1995 Nov 21.
Article in English | MEDLINE | ID: mdl-7495834

ABSTRACT

Treatment of relaxed skinned rabbit psoas muscle fibers with 0.1 mM N-phenylmaleimide (NPM) for 1 h locks all of the crossbridges in a weakly-binding state resembling that of the myosin.ATP crossbridge. Under these conditions, NPM reacts mainly with myosin heavy chain (Barnett et al. (1992) Biophys. J. 61, 358-367). Here the specific sites for that reaction are explored. Small bundles of rabbit psoas muscle fibers were treated with Triton X-100 to make the fiber sarcolemmas permeable. The bundles were treated with 0.1 mM [14C]NPM for 1 h, and homogenized for SDS-PAGE. 43 +/- 2.2% of the muscle fiber protein ran in the myosin heavy chain band, the same as for untreated fibers. An alkylating stoichiometry of 2.2 +/- 0.33 moles NPM per mole myosin heavy chain was determined. Exhaustive trypsin digestion followed by two-dimensional thin-layer chromatography and reverse-phase HPLC revealed two major sites on myosin heavy chain for NPM binding. The sites contained about the same amount of linked NPM, suggesting that the reaction stoichiometry of each site under the conditions studied is approx. 1 mol NPM/mol myosin heavy chain. Comparison of the labeled tryptic peptides with NPM-reacted synthetic SH1 and SH2 tryptic peptides and analysis of the treated fiber bundles' ATPase activity suggested that the sites for NPM reaction on myosin heavy chain when it locks crossbridges in a weakly-binding state are Cys-697 (SH2) and Cys-707 (SH1).


Subject(s)
Maleimides/metabolism , Muscle, Skeletal/metabolism , Myosin Heavy Chains/metabolism , Animals , Calcium/metabolism , Chromatography, High Pressure Liquid , Octoxynol , Rabbits
SELECTION OF CITATIONS
SEARCH DETAIL