Showing papers by "National Institutes of Health published in 1994"
TL;DR: Evidence is presented that performance measures can validly characterize older persons across a broad spectrum of lower extremity function and that performance and self-report measures may complement each other in providing useful information about functional status.
Abstract: Background A short battery of physical performance tests was used to assess lower extremity function in more than 5,000 persons age 71 years and older in three communities. Methods Balance, gait, strength, and endurance were evaluated by examining ability to stand with the feet together in the side-by-side, semi-tandem, and tandem positions, time to walk 8 feet, and time to rise from a chair and return to the seated position 5 times. Results A wide distribution of performance was observed for each test. Each test and a summary performance scale, created by summing categorical rankings of performance on each test, were strongly associated with self-report of disability. Both self-report items and performance tests were independent predictors of short-term mortality and nursing home admission in multivariate analyses. However, evidence is presented that the performance tests provide information not available from self-report items. Of particular importance is the finding that in those at the high end of the functional spectrum, who reported almost no disability, the performance test scores distinguished a gradient of risk for mortality and nursing home admission. Additionally, within subgroups with identical self-report profiles, there were systematic differences in physical performance related to age and sex. Conclusion This study provides evidence that performance measures can validly characterize older persons across a broad spectrum of lower extremity function. Performance and self-report measures may complement each other in providing useful information about functional status.
7,417 citations
TL;DR: A strong candidate for the 17q-linked BRCA1 gene, which influences susceptibility to breast and ovarian cancer, has been identified by positional cloning methods.
Abstract: A strong candidate for the 17q-linked BRCA1 gene, which influences susceptibility to breast and ovarian cancer, has been identified by positional cloning methods. Probable predisposing mutations have been detected in five of eight kindreds presumed to segregate BRCA1 susceptibility alleles. The mutations include an 11-base pair deletion, a 1-base pair insertion, a stop codon, a missense substitution, and an inferred regulatory mutation. The BRCA1 gene is expressed in numerous tissues, including breast and ovary, and encodes a predicted protein of 1863 amino acids. This protein contains a zinc finger domain in its amino-terminal region, but is otherwise unrelated to previously described proteins. Identification of BRCA1 should facilitate early diagnosis of breast and ovarian cancer susceptibility in some individuals as well as a better understanding of breast cancer biology.
6,118 citations
TL;DR: The possibility that the immune system does not care about self and non-self, that its primary driving force is the need to detect and protect against danger, and that it does not do the job alone, but receives positive and negative communications from an extended network of other bodily tissues is discussed.
Abstract: For many years immunologists have been well served by the viewpoint that the immune system's primary goal is to discriminate between self and non-self. I believe that it is time to change viewpoints and, in this essay, I discuss the possibility that the immune system does not care about self and non-self, that its primary driving force is the need to detect and protect against danger, and that it does not do the job alone, but receives positive and negative communications from an extended network of other bodily tissues.
4,825 citations
TL;DR: The diagonal and off-diagonal elements of the effective self-diffusion tensor, Deff, are related to the echo intensity in an NMR spin-echo experiment.
3,645 citations
TL;DR: In pregnant women with mildly symptomatic HIV disease and no prior treatment with antiretroviral drugs during the pregnancy, a regimen consisting of zidovudine given ante partum and intra partum to the mother and to the newborn for six weeks reduced the risk of maternal-infant HIV transmission by approximately two thirds.
Abstract: Background and Methods Maternal-infant transmission is the primary means by which young children become infected with human immunodeficiency virus type 1 (HIV). We conducted a randomized, double-blind, placebo-controlled trial of the efficacy and safety of zidovudine in reducing the risk of maternal-infant HIV transmission. HIV-infected pregnant women (14 to 34 weeks' gestation) with CD4+ T-lymphocyte counts above 200 cells per cubic millimeter who had not received antiretroviral therapy during the current pregnancy were enrolled. The zidovudine regimen included antepartum zidovudine (100 mg orally five times daily), intrapartum zidovudine (2 mg per kilogram of body weight given intravenously over a one-hour period, then 1 mg per kilogram per hour until delivery), and zidovudine for the newborn (2 mg per kilogram orally every six hours for six weeks). Infants with at least one positive HIV culture of peripheral-blood mononuclear cells were classified as HIV-infected. Results From April 1991 through Decemb...
3,604 citations
TL;DR: Findings suggest that MTS1 mutations are involved in tumor formation in a wide range of tissues.
Abstract: A putative tumor suppressor locus on the short arm of human chromosome 9 has been localized to a region of less than 40 kilobases by means of homozygous deletions in melanoma cell lines. This region contained a gene, Multiple Tumor Suppressor 1 (MTS1), that encodes a previously identified inhibitor (p16) of cyclin-dependent kinase 4. MTS1 was homozygously deleted at high frequency in cell lines derived from tumors of lung, breast, brain, bone, skin, bladder, kidney, ovary, and lymphocyte. Melanoma cell lines that carried at least one copy of MTS1 frequently carried nonsense, missense, or frameshift mutations in the gene. These findings suggest that MTS1 mutations are involved in tumor formation in a wide range of tissues.
2,855 citations
TL;DR: New methods for determination ofcarbonyl content are presented, which are based on the reaction of carbonyl groups with 2,4-dinitrophenylhydrazine to form a 2, 4-d Initrophenolhydrazone, which provide substantial improvements in both sensitivity and specificity.
Abstract: Publisher Summary Enzymes and structural proteins may be attacked whenever free radicals are generated. As a consequence, oxidative modification of proteins may occur in a variety of physiologic and pathologic processes. Although the distinction is sometimes arbitrary, these modifications may be primary or secondary. Primary modifications occur in metal-catalyzed oxidation, radiation-mediated oxidation, and oxidation by ozone or oxides of nitrogen. Secondary modifications occur when proteins are modified by molecules generated by oxidation of other molecules. One important example is the covalent modification of proteins by hydroxynonenal produced by oxidation of lipids. Carbonyl groups (aldehydes and ketones) may be introduced into proteins by any of these reactions, and the appearance of such carbonyl groups is taken as presumptive evidence of oxidative modification. Assay of carbonyl groups in proteins provides a convenient technique for detecting and quantifying oxidative modification of proteins. This chapter presents new methods for determination of carbonyl content, which are based on the reaction of carbonyl groups with 2,4-dinitrophenylhydrazine to form a 2,4-dinitrophenylhydrazone. The assays provide substantial improvements in both sensitivity and specificity.
2,529 citations
TL;DR: Recombinant human alpha-interferon in patients with chronic nonA-nonB hepatitis and factors predictive of response to interferon alpha therapy in HCV infection are studied.
2,516 citations
2,141 citations
TL;DR: Restricting protein intake and controlling hypertension delay the progression of renal disease in animals and in patients with various chronic renal diseases.
Abstract: Background Restricting protein intake and controlling hypertension delay the progression of renal disease in animals. We tested these interventions in 840 patients with various chronic renal diseases. Methods In study 1, 585 patients with glomerular filtration rates of 25 to 55 ml per minute per 1.73 m2 of body-surface area were randomly assigned to a usual-protein diet or a low-protein diet (1.3 or 0.58 g of protein per kilogram of body weight per day) and to a usual- or a low-blood-pressure group (mean arterial pressure, 107 or 92 mm Hg). In study 2, 255 patients with glomerular filtration rates of 13 to 24 ml per minute per 1.73 m2 were randomly assigned to the low-protein diet (0.58 g per kilogram per day) or a very-low-protein diet (0.28 g per kilogram per day) with a keto acid-amino acid supplement, and a usual- or a low-blood-pressure group (same values as those in study 1). An 18-to-45-month follow-up was planned, with monthly evaluations of the patients. Results The mean follow-up was 2.2 years. ...
2,113 citations
Journal Article•
TL;DR: The results support the idea that WAF1/CIP1 is a critical downstream effector in the p53-specific pathway of growth control in mammalian cells.
Abstract: The tumor growth suppressor WAF1/CIP1 was recently shown to be induced by p53 and to be a potent inhibitor of cyclin-dependent kinases In the present studies, we sought to determine the relationship between the expression of WAF1/CIP1 and endogenous regulation of p53 function WAF1/CIP1 protein was first localized to the nucleus of cells containing wild-type p53 and undergoing G 1 arrest WAF1/CIP1 was induced in wild-type p53-containing cells by exposure to DNA damaging agents, but not in mutant p53 -containing cells The induction of WAF1/CIP1 protein occurred in cells undergoing either p53 -associated G 1 arrest or apoptosis but not in cells induced to arrest in G 1 or to undergo apoptosis through p53 -independent mechanisms DNA damage led to increased levels of WAF1/CIP1 in cyclin E-containing complexes and to an associated decrease in cyclin-dependent kinase activity These results support the idea that WAF1/CIP1 is a critical downstream effector in the p53 -specific pathway of growth control in mammalian cells
TL;DR: The DIGS is designed to be employed by interviewers who exercise significant clinical judgment and who summarize information in narrative form as well as in ratings, and should be useful as part of archival data gathering for genetic studies of major affective disorders, schizophrenia, and related conditions.
Abstract: This the Diagnostic Interview for Genetic Studies (DIGS), a clinical interview especially constructed for the assessment of major mood and psychotic disorders and their spectrum conditions The DIGS, which was developed and piloted as a collaborative effort of investigators from sites in the National Institute of Mental Health (NIMH) Genetics Initiative, has the following additional features: (1) polydiagnostic capacity; (2) a detailed assessment of the course of the illness, chronology of psychotic and mood syndromes, and comorbidity; (3) additional phenomenologic assessments of symptoms; and (4) algorithmic scoring capability The DIGS is designed to be employed by interviewers who exercise significant clinical judgment and who summarize information in narrative form as well as in ratings A two-phase test-retest (within-site, between-site) reliability study was carried out for DSM-III-R criteria—based major depression, bipolar disorder, schizophrenia, and schizoaffective disorder Reliabilities using algorithms were excellent (073 to 095), except for schizoaffective disorder, for which disagreement on estimates of duration of mood syndromes relative to psychosis reduced reliability A final best-estimate process using medical records and information from relatives as well as algorithmic diagnoses is expected to be more reliable in making these distinctions The DIGS should be useful as part of archival data gathering for genetic studies of major affective disorders, schizophrenia, and related conditions
TL;DR: A strategy of initial CABG surgery is associated with lower mortality than one of medical management with delayed surgery if necessary, especially in high-risk and medium- risk patients with stable coronary heart disease, and in low-risk patients, the limited data show a non-significant trend towards greater mortality with CABGs.
TL;DR: Findings from positron emission tomography activation studies have localized these pathways within the human brain, yielding insights into cortical hierarchies, specialization of function, and attentional mechanisms.
TL;DR: A method for detecting significant and regionally specific correlations between sensory input and the brain's physiological response, as measured with functional magnetic resonance imaging (MRI), is presented in this paper.
Abstract: A method for detecting significant and regionally specific correlations between sensory input and the brain's physiological response, as measured with functional magnetic resonance imaging (MRI), is presented in this paper. The method involves testing for correlations between sensory input and the hemodynamic response after convolving the sensory input with an estimate of the hernodynamic response function. This estimate is obtained without reference to any assumed input. To lend the approach statistical validity, it is brought into the framework of statistical parametric mapping by using a measure of cross-correlations between sensory input and hemodynamic response that is valid in the presence of intrinsic autocorrelations. These autocorrelations are necessarily present, due to the hemodynamic response function or temporal point spread function.
TL;DR: The identification of VHL mutations in a majority of localized and advanced sporadic renal carcinomas and in a second form of hereditary renal carcinoma indicates that the VHL gene plays a critical part in the origin of this malignancy.
Abstract: Multiple, bilateral renal carcinomas are a frequent occurrence in von Hippel-Lindau (VHL) disease. To elucidate the aetiological role of the VHL gene in human kidney tumorigenesis, localized and advanced tumours from 110 patients with sporadic renal carcinoma were analysed for VHL mutations and loss of heterozygosity (LOH). VHL mutations were identified in 57% of clear cell renal carcinomas analysed and LOH was observed in 98% of those samples. Moreover, VHL was mutated and lost in a renal tumour from a patient with familial renal carcinoma carrying the constitutional translocation, t(3;8)(p14;q24). The identification of VHL mutations in a majority of localized and advanced sporadic renal carcinomas and in a second form of hereditary renal carcinoma indicates that the VHL gene plays a critical part in the origin of this malignancy.
TL;DR: The findings suggest that aberrant methylation of CpG islands may participate in the tumor-suppressor gene inactivations which initiate or cause progression of common human cancers.
Abstract: Mutational inactivation and allelic loss of the von Hippel-Lindau (VHL) gene appear to be causal events for the majority of spontaneous clear-cell renal carcinomas. We now show that hypermethylation of a normally unmethylated CpG island in the 5' region provides another potentially important mechanism for inactivation of the VHL gene in a significant portion of these cancers. This hypermethylation was found in 5 of 26 (19%) tumors examined. Four of these had lost one copy of VHL while one retained two heavily methylated alleles. Four of the tumors with VHL hypermethylation had no detectable mutations, whereas one had a missense mutation in addition to hypermethylation of the single retained allele. As would be predicted for the consequence of methylation in this 5' CpG island, none of the 5 tumors expressed the VHL gene. In contrast, normal kidney and all tumors examined with inactivating VHL gene mutations but no CpG island methylation had expression. In a renal cell culture line, treatment with 5-aza-2'-deoxycytidine resulted in reexpression of the VHL gene. These findings suggest that aberrant methylation of CpG islands may participate in the tumor-suppressor gene inactivations which initiate or cause progression of common human cancers.
TL;DR: IL-4 strikingly diminishes priming forIFN gamma production, although this inhibitory effect is blunted in the presence of IL-12, and IFN gamma similarly diminishesPriming for IL-4 production; this effect is principally observed when low concentrations of IL -4 are used in the priming culture.
Abstract: Naive CD4+ T cells when stimulated produce IL-2 as their major lymphokine. Upon priming, these cells develop into cells that produce either IFN gamma, TNF beta, and IL-2 or IL-4 and its congeners. The former cells are designated TH1-like, and the latter TH2-like. Here we review the regulation of the differentiation of naive CD4 cells into IFN gamma- or IL-4-producers. The dominant factors that determine such differentiation are lymphokines and other cytokines. IL-2 itself appears to be required for naive cells to develop into TH1- or TH2-like cells but is not deterministic of their differentiation fate. If IL-4 is also present during the priming period, the resultant CD4+ T cells produce IL-4 upon restimulation; the development of IFN gamma-producing cells is strikingly inhibited by IL-4. In the absence of IL-4, priming for IFN gamma-production occurs, but this is markedly enhanced by IL-12. The role of IFN gamma in enhancing priming for IFN gamma-production is not fully resolved. In some in vitro systems, it appears to act together with IL-12 to enhance such production. Anti-IFN gamma diminishes priming for IFN gamma production in vivo. Lymphokines also exert a "cross-regulatory" or inhibitory effect. As noted above, IL-4 strikingly diminishes priming for IFN gamma production, although this inhibitory effect is blunted in the presence of IL-12. IFN gamma similarly diminishes priming for IL-4 production; this effect is principally observed when low concentrations of IL-4 are used in the priming culture. Although other factors may play a role in the determination of lymphokine-producing phenotype, such as antigen dose, type of antigen-presenting cell, and expression of accessory molecules and hormones, these effects appear to be secondary to the dominant role of the lymphokines and cytokines.
Journal Article•
TL;DR: A method to predict the relative binding strengths of all possible nonapeptides to the MHC class I molecule HLA-A2 has been developed based on experimental peptide binding data as mentioned in this paper.
Abstract: A method to predict the relative binding strengths of all possible nonapeptides to the MHC class I molecule HLA-A2 has been developed based on experimental peptide binding data. These data indicate that, for most peptides, each side-chain of the peptide contributes a certain amount to the stability of the HLA-A2 complex that is independent of the sequence of the peptide. To quantify these contributions, the binding data from a set of 154 peptides were combined together to generate a table containing 180 coefficients (20 amino acids x 9 positions), each of which represents the contribution of one particular amino acid residue at a specified position within the peptide to binding to HLA-A2. Eighty peptides formed stable HLA-A2 complexes, as assessed by measuring the rate of dissociation of beta 2m. The remaining 74 peptides formed complexes that had a half-life of beta 2m dissociation of less than 5 min at 37 degrees C, or did not bind to HLA-A2, and were included because they could be used to constrain the values of some of the coefficients. The "theoretical" binding stability (calculated by multiplying together the corresponding coefficients) matched the experimental binding stability to within a factor of 5. The coefficients were then used to calculate the theoretical binding stability for all the previously identified self or antigenic nonamer peptides known to bind to HLA-A2. The binding stability for all other nonamer peptides that could be generated from the proteins from which these peptides were derived was also predicted. In every case, the previously described HLA-A2 binding peptides were ranked in the top 2% of all possible nonamers for each source protein. Therefore, most biologically relevant nonamer peptides should be identifiable using the table of coefficients. We conclude that the side-chains of most nonamer peptides to the first approximation bind independently of one another to the HLA-A2 molecule.
TL;DR: In this paper, the authors measured the NO in patients with asthma using a slow vital capacity manoeuvre and an adapted chemiluminescence analyser and found that NO was detectable in exhaled air of 67 control subjects (mean peak concentration 80·2 [SE4·1] ppb) and was significantly reduced by inhaling the specific NO synthase inhibitor N G -monomethyl-Larginine.
TL;DR: It is demonstrated that HSP participation in multimolecular complex formation is required for src-mediated transformation and can provide a target for drug modulation.
Abstract: The molecular mechanisms by which oncogenic tyrosine kinases induce cellular transformation are unclear. Herbimycin A, geldanamycin, and certain other benzoquinone ansamycins display an unusual capacity to revert tyrosine kinase-induced oncogenic transformation. As an approach to the study of v-src-mediated transformation, we examined ansamycin action in transformed cells and found that drug-induced reversion could be achieved without direct inhibition of src phosphorylating activity. To identify mechanisms other than kinase inhibition for drug-mediated reversion, we prepared a solid phase-immobilized geldanamycin derivative and affinity precipitated the molecular targets with which the drug interacted. In a range of cell lines, immobilized geldanamycin bound elements of a major class of heat shock protein (HSP90) in a stable and pharmacologically specific manner. Consistent with these binding data, we found that soluble geldanamycin and herbimycin A inhibited specifically the formation of a previously described src-HSP90 heteroprotein complex. A related benzoquinone ansamycin that failed to revert transformed cells did not inhibit the formation of this complex. These results demonstrate that HSP participation in multimolecular complex formation is required for src-mediated transformation and can provide a target for drug modulation.
Washington University in St. Louis1, Stanford University2, National Institutes of Health3, Pennsylvania State University4, Harvard University5, Vanderbilt University6, University of Tennessee Health Science Center7, University of Washington8, Case Western Reserve University9, George Washington University10, Johns Hopkins University11, Baylor College of Medicine12, Howard University13, University of California, Los Angeles14, University of Michigan15
TL;DR: It is concluded that ulcer patients with H. pylori infection require treatment with antimicrobial agents in addition to antisecretory drugs whether on first presentation with the illness or on recurrence.
Abstract: The National Institutes of Health Consensus Development Conference onHelicobacter pyloriin Peptic Ulcer Disease brought together specialists in gastroenterology, surgery, infectious diseases, epidemiology, and pathology, as well as the public to address the following questions: (1) What is the causal relationship ofH pylorito upper gastrointestinal disease? (2) How does one diagnose and eradicateH pyloriinfection? (3) Does eradication ofH pyloriinfection benefit the patient with peptic ulcer disease? (4) What is the relationship betweenH pyloriinfection and gastric malignancy? (5) WhichH pylori—infected patients should be treated? (6) What are the most important questions that must be addressed by future research inH pyloriinfections? Following 1½ days of presentations by experts and discussion by the audience, a consensus panel weighed the evidence and prepared their consensus statement. Among their findings, the consensus panel concluded that (1) ulcer patients withH pyloriinfection require treatment with antimicrobial agents in addition to antisecretory drugs whether on first presentation with the illness or on recurrence; (2) the value of treating of nonulcerative dyspepsia patients withH pyloriinfection remains to be determined; and (3) the interesting relationship betweenH pyloriinfection and gastric cancers requires further exploration. (JAMA. 1994;272:65-69)
TL;DR: By using convection to supplement simple diffusion, enhanced distribution of large and small molecules can be obtained in the brain while achieving drug concentrations orders of magnitude greater than systemic levels.
Abstract: For many compounds (neurotrophic factors, antibodies, growth factors, genetic vectors, enzymes) slow diffusion in the brain severely limits drug distribution and effect after direct drug administration into brain parenchyma. We investigated convection as a means to enhance the distribution of the large and small molecules 111In-labeled transferrin (111In-Tf; M(r), 80,000) and [14C]sucrose (M(r), 359) over centimeter distances by maintaining a pressure gradient during interstitial infusion into white matter to generate bulk flow through the brain interstitium. The volume of distribution (Vd) containing > or = 1% concentration of infusion solution increased linearly with the infusion volume (Vi) for 111In-Tf(Vd/Vi, 6:1) and [14C]sucrose (Vd/Vi, 13:1). Twenty-four hours after infusion, the distribution of 111In-Tf was increased and more homogeneous, and penetration into gray matter had occurred. By using convection to supplement simple diffusion, enhanced distribution of large and small molecules can be obtained in the brain while achieving drug concentrations orders of magnitude greater than systemic levels.
TL;DR: Modulation of the amplitude of motor evoked potentials (MEPs) produced in the target muscle during rTMS showed a pattern of inhibitory and excitatory effects which depended on the rT MS frequency and intensity, which suggests that the spread might be due to the breakdown of inhibitORY connections or the recruitment of excited pathways, whereas the post-stimulation facilitation may beDue to a transient increase in the efficacy of excitatories.
Abstract: We applied trains of focal, rapid-rate transcranial magnetic stimulation (rTMS) to the motor cortex of 14 healthy volunteers with recording of the EMG from the contralateral abductor pollicis brevis, extensor carpi radialis, biceps brachii and deltoid muscles. Modulation of the amplitude of motor evoked potentials (MEPs) produced in the target muscle during rTMS showed a pattern of inhibitory and excitatory effects which depended on the rTMS frequency and intensity. With the magnetic coil situated over the optimal scalp position for activating the abductor pollicis brevis, rTMS led to spread of excitation, as evident from the induction of progressively larger MEPs in the other muscles. The number of pulses inducing this spread of excitation decreased with increasing rTMS frequency and intensity. Latency of the MEPs produced in the other muscles during the spread of excitation was significantly longer than that produced by single-pulse TMS applied to the optimal scalp positions for their activation. The difference in MEP latency could be explained by a delay in intracortical conduction along myelinated cortico-cortical pathways. Following rTMS, a 3–4 min period of increased excitability was demonstrated by an increase in the amplitude of MEPs produced in the target muscles by single-pulse TMS. Nevertheless, repeated rTMS trains applied I min apart led to similar modulation of the responses and to spread of excitation after approximately the same number of pulses. This suggests that the spread might be due to the breakdown of inhibitory connections or the recruitment of excitatory pathways, whereas the post-stimulation facilitation may be due to a transient increase in the efficacy of excitatory synapses.
TL;DR: Surprising developments suggest that in addition to leukocyte-mediated inflammation, the chemokines may also be involved in erythrocyte function and, through molecular mimicry, in microbial pathogenesis.
Abstract: Leukocytes migrate from the blood to sites of inflammation in response to locally produced chemoattractants that activate specific cell surface receptors. The primary structures of leukocyte receptors for N-formyl peptides, C5a, platelet-activating factor, and 8 of the 18 known human chemokines (interleukin-8 and related molecules) have been deduced from cloned cDNAs. All of these are seven-transmembrane-domain rhodopsin-like G protein-coupled receptors. Biochemical and molecular genetic analysis of the chemoattractant receptors indicates that the chemoattractants may have both broadly overlapping as well as specialized roles in the regulation of acute and chronic inflammation. Interestingly, the chemokine receptors have functional homologues in human cytomegalovirus and Herpesvirus saimiri. Moreover, the Duffy antigen, which mediates invasion of erythrocytes by Plasmodium vivax, a major cause of malaria, is also a chemokine binding protein. These surprising developments suggest that in addition to leukocyte-mediated inflammation, the chemokines may also be involved in erythrocyte function and, through molecular mimicry, in microbial pathogenesis.
TL;DR: Results suggest that mutation of BRCA1 may not be critical in the development of the majority of breast and ovarian cancers that arise in the absence of a mutant germline allele.
Abstract: Loss of heterozygosity data from familial tumors suggest that BRCA1, a gene that confers susceptibility to ovarian and early-onset breast cancer, encodes a tumor suppressor. The BRCA1 region is also subject to allelic loss in sporadic breast and ovarian cancers, an indication that BRCA1 mutations may occur somatically in these tumors. The BRCA1 coding region was examined for mutations in primary breast and ovarian tumors that show allele loss at the BRCA1 locus. Mutations were detected in 3 of 32 breast and 1 of 12 ovarian carcinomas; all four mutations were germline alterations and occurred in early-onset cancers. These results suggest that mutation of BRCA1 may not be critical in the development of the majority of breast and ovarian cancers that arise in the absence of a mutant germline allele.
TL;DR: Nine melanoma-specific mutations were detected in 9p21-linked, but not in 1p36- linked, families, thereby confirming previous reports of genetic heterogeneity and will confirm those causally related to the development of familial melanoma.
Abstract: The p16 gene is located in chromosome 9p21, a region that is linked to familial melanoma and homozygously deleted in many tumour cell lines. We describe eight p16 germline substitutions (one nonsense, one splice donor site and six missense) in 13/18 familial melanoma kindreds. Six of these mutations were identified in 33/36 melanoma cases in nine families, whereas two were detected in normal controls and are not disease-related. The melanoma-specific mutations were detected in 9p21-linked, but not in 1p36-linked, families, thereby confirming previous reports of genetic heterogeneity. Functional analyses of these mutations will confirm those causally related to the development of familial melanoma.
TL;DR: In this article, the three-dimensional solution structure of the complex between calcium-bound calmodulin (Ca(2+)-CaM) and a 26-residue synthetic peptide comprising the CaM binding domain (residues 577 to 602) of skeletal muscle myosin light chain kinase, has been determined using multidimensional heteronuclear filtered and separated nuclear magnetic resonance spectroscopy.
Abstract: The three-dimensional solution structure of the complex between calcium-bound calmodulin (Ca(2+)-CaM) and a 26-residue synthetic peptide comprising the CaM binding domain (residues 577 to 602) of skeletal muscle myosin light chain kinase, has been determined using multidimensional heteronuclear filtered and separated nuclear magnetic resonance spectroscopy. The two domains of CaM (residues 6 to 73 and 83 to 146) remain essentially unchanged upon complexation. The long central helix (residues 65 to 93), however, which connects the two domains in the crystal structure of Ca(2+)-CaM, is disrupted into two helices connected by a long flexible loop (residues 74 to 82), thereby enabling the two domains to clamp residues 3 to 21 of the bound peptide, which adopt a helical conformation. The overall structure of the complex is globular, approximating an ellipsoid of dimensions 47 by 32 by 30 angstroms. The helical peptide is located in a hydrophobic channel that passes through the center of the ellipsoid at an angle of approximately 45 degrees with its long axis. The complex is mainly stabilized by hydrophobic interactions which, from the CaM side, involve an unusually large number of methionines. Key residues of the peptide are Trp4 and Phe17, which serve to anchor the amino- and carboxyl-terminal halves of the peptide to the carboxyl- and amino-terminal domains of CaM, respectively. Sequence comparisons indicate that a number of peptides that bind CaM with high affinity share this common feature containing either aromatic residues or long-chain hydrophobic ones separated by a stretch of 12 residues, suggesting that they interact with CaM in a similar manner.