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1.
medRxiv ; 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38328243

RESUMO

Background: HPV-associated oropharyngeal cancer (HPV+OPSCC) is the most common HPV-associated cancer in the United States yet unlike cervical cancer lacks a screening test. HPV+OPSCCs are presumed to start developing 10-15 years prior to clinical diagnosis. Circulating tumor HPV DNA (ctHPVDNA) is a sensitive and specific biomarker for HPV+OPSCC. Taken together, blood-based screening for HPV+OPSCC may be feasible years prior to diagnosis. Methods: We developed an HPV whole genome sequencing assay, HPV-DeepSeek, with 99% sensitivity and specificity at clinical diagnosis. 28 plasma samples from HPV+OPSCC patients collected 1.3-10.8 years prior to diagnosis along with 1:1 age and gender-matched controls were run on HPV-DeepSeek and an HPV serology assay. Results: 22/28 (79%) of cases and 0/28 controls screened positive for HPV+OPSCC with 100% detection within four years of diagnosis and a maximum lead time of 7.8 years. We next applied a machine learning model classifying 27/28 cases (96%) with 100% detection within 10 years. Plasma-based PIK3CA gene mutations, viral genome integration events and HPV serology were used to orthogonally validate cancer detection with 68% (19/28) of the cohort having multiple cancer signals detected. Molecular fingerprinting of HPV genomes was performed across patients demonstrating that each viral genome was unique, ruling out contamination. In patients with tumor blocks from diagnosis (15/28), molecular fingerprinting was performed within patients confirming the same viral genome across time. Conclusions: We demonstrate accurate blood-based detection of HPV-associated cancers with lead times up to 10 years before clinical cancer diagnosis and in doing so, highlight the enormous potential of ctDNA-based cancer screening.

2.
J Cancer ; 14(2): 299-305, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36741257

RESUMO

Introduction: Urinary dysfunction has a strong impact clinically, socially, and economically. Although the development of acute urinary dysfunction in hospitalized patients with cancer is common in clinical practice, its occurrence and management strategies are scant in the literature. It has been reported as one of the more common medical complications in patients with cancer undergoing acute inpatient rehabilitation. This study assessed the frequency of and risk factors for acute urinary dysfunction among these patients and identified the interventions used for management. Methods: This is a retrospective study of consecutive patients admitted to a National Cancer Institute Comprehensive Cancer Center's acute inpatient rehabilitation service from 9/1/2020 through 3/15/2021. We excluded patients that were readmissions during the study time frame. We collected patients' demographic, clinical, and functional data. We defined acute urinary dysfunction as the development of any new urinary symptom(s) or diagnosis, which involved additional work-up and/or management after admission to the acute inpatient rehabilitation service. Results: Of the 176 total patients included in this study, 47 (27%; 95% confidence interval [CI], 20-34) patients had acute urinary dysfunction. The most frequent diagnoses were urinary tract infection (32%) and neurogenic bladder (26%). The most common tests were urine cultures (32%) and urinalyses (30%). The most commonly prescribed medications were antibiotics (32%) and alpha-1 blockers (15%). Other most frequent interventions included timed voiding (34%) and intermittent catheterization with bladder scans (28%). Acute urinary dysfunction was associated with an increased length of stay on the inpatient rehabilitation service (odds ratio [OR], 1.13; 95% CI, 1.06-1.20; P<.001), surgery during the index admission (OR, 2.50; 95% CI, 1.21-5.16; P=.014), and fecal incontinence (OR, 6.41; 95% CI, 1.83-22.44; P=.004). Conclusion: Acute urinary dysfunction was noted to be a substantial problem in this cohort. This is an overlooked dimension of inpatient cancer rehabilitation that deserves more attention. Patients at risk for acute urinary dysfunction may benefit from close monitoring for medical management and rehabilitation interventions to maximize functional independence with bladder care. More research regarding acute urinary dysfunction types and management approaches in post-acute care settings for patients with cancer is justified.

3.
Lab Chip ; 23(2): 239-250, 2023 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-36594179

RESUMO

Tissue chip (TC) devices, also known as microphysiological systems (MPS) or organ chips (OCs or OoCs), seek to mimic human physiology on a small scale. They are intended to improve upon animal models in terms of reproducibility and human relevance, at a lower monetary and ethical cost. Virtually all TC systems are analyzed at an endpoint, leading to widespread recognition that new methods are needed to enable sensing of specific biomolecules in real time, as they are being produced by the cells. To address this need, we incorporated photonic biosensors for inflammatory cytokines into a model TC. Human bronchial epithelial cells seeded in a microfluidic device were stimulated with lipopolysaccharide, and the cytokines secreted in response sensed in real time. Sensing analyte transport through the TC in response to disruption of tissue barrier was also demonstrated. This work demonstrates the first application of photonic sensors to a human TC device, and will enable new applications in drug development and disease modeling.


Assuntos
Técnicas Biossensoriais , Dispositivos Lab-On-A-Chip , Humanos , Reprodutibilidade dos Testes , Células Epiteliais , Pulmão
4.
World J Orthop ; 13(7): 631-643, 2022 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-36051376

RESUMO

BACKGROUND: Rotator cuff pathology is a very common source of shoulder pain. Similarly, osteoarthritis of the glenohumeral joint can cause shoulder pain and produce similar symptoms. Surgical management can be indicated for both pathologies, however, outcomes data is limited when examining rotator cuff repair (RCR) in the setting of glenohumeral arthritis (GHOA). Thus, this study sought to determine outcomes for patients who undergo RCR in the setting of GHOA. AIM: To evaluate if a relationship exists between outcomes of RCR in the setting of GHOA. METHODS: This was a retrospective analysis of patients who underwent arthroscopic rotator cuff repair with concurrent glenohumeral osteoarthritis between 2010-2017. Patients were stratified based on rotator cuff tear size and glenohumeral osteoarthritis severity. Cohorts were paired 1:1 with patients without glenohumeral osteoarthritis. Patients included had a minimum two year follow-up. Rate of conversion to total shoulder arthroplasty, complication rates following initial surgery, and patient-reported outcome measures were collected. RESULTS: A total of 142 patients were included. The number of patients that required total shoulder arthroplasty within two years after index surgery was low. 2/71 (2.8%) patients with GHOA, and 1/71 (1.4%) without GHOA. Following rotator cuff repair, both groups showed favorable patient-reported outcomes. CONCLUSION: Patients with glenohumeral osteoarthritis who underwent arthroscopic rotator cuff repair showed comparable outcomes to patients without glenohumeral osteoarthritis.

5.
PLoS One ; 17(1): e0262366, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35061783

RESUMO

BACKGROUND: Becoming a father impacts men's health and wellbeing, while also contributing to the health and wellbeing of mothers and children. There is no large-scale, public health surveillance system aimed at understanding the health and behaviors of men transitioning into fatherhood. The purpose of this study was to describe piloted randomized approaches of a state-based surveillance system examining paternal behaviors before and after their infant's birth to better understand the health needs of men and their families during the transition to parenthood. METHODS: During October 2018-July 2019, 857 fathers in Georgia were sampled 2-6 months after their infant's birth from birth certificates files and surveyed via mail, online or telephone, in English or Spanish, using two randomized approaches: Indirect-to-Dads and Direct-to-Dads. Survey topics included mental and physical health, healthcare, substance use, and contraceptive use. FINDINGS: Weighted response rates (Indirect-to-Dads, 33%; Direct-to-Dads, 31%) and population demographics did not differ by approach. Respondents completed the survey by mail (58%), online (28%) or telephone (14%). Among 266 fathers completing the survey, 55% had a primary care physician, and 49% attended a healthcare visit for themselves during their infant's mother's pregnancy or since their infant's birth. Most fathers were overweight or had obesity (70%) while fewer reported smoking cigarettes (19%), binge drinking (13%) or depressive symptoms (10%) since their infant's birth. CONCLUSIONS: This study tests a novel approach for obtaining population-based estimates of fathers' perinatal health behaviors, with comparable response rates from two pragmatic approaches. The pilot study results quantify a number of public health needs related to fathers' health and healthcare access.


Assuntos
Pai/psicologia , Vigilância em Saúde Pública/métodos , Medição de Risco/métodos , Adulto , Feminino , Georgia , Humanos , Masculino , Saúde Mental/estatística & dados numéricos , Poder Familiar/psicologia , Comportamento Paterno/psicologia , Projetos Piloto , Gravidez , Inquéritos e Questionários
6.
J Womens Health (Larchmt) ; 31(3): 356-361, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35041492

RESUMO

Background: Understanding the accuracy of a woman's perceived breast cancer risk can enhance shared decision-making about breast cancer screening through provider and patient discussion. We aim to report and compare women's perceived lifetime breast cancer risk to calculated lifetime breast cancer risk. Methods: Women presenting to Mayo Clinic in Arizona and Minnesota in July 2016 completed a survey assessing their perceived breast cancer risk. Lifetime Gail risk scores were calculated from questions pertaining to health history and were then compared with perceived breast cancer risk. Results: A total of 550 predominantly white, married, and well-educated (≥college) women completed surveys. Using lifetime Gail risk scores, 5.6% were classified as high risk (>20% lifetime risk), 7.7% were classified as intermediate risk (15%-20%), and 86.6% were classified as average risk (<15%). Of the 27 women who were classified as high risk, 18 (66.7%) underestimated their risk and of the 37 women who were intermediate risk, 12 (32.4%) underestimated risk. Women more likely to underestimate their risk had a reported history of an abnormal mammogram and at least one or more relative with a history of breast cancer. Surveyed women tended to overestimate risk 4.3 (130/30) times as often as they underestimated risk. Conclusion: In a group of predominantly white, educated, and married cohort of women, there was a large portion of women in the elevated risk groups who underestimated risk. Specific aspects of medical history were associated with underestimation including a history of abnormal mammogram and family history of breast cancer. Overall, in our sample, more women overestimated than underestimated risk.


Assuntos
Neoplasias da Mama , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/prevenção & controle , Detecção Precoce de Câncer , Feminino , Humanos , Medição de Risco , Fatores de Risco , Inquéritos e Questionários
7.
J Womens Health (Larchmt) ; 28(3): 302-313, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30204537

RESUMO

BACKGROUND: In recently updated breast cancer screening guidelines, the American Cancer Society (ACS) and United States Preventive Services Task Force (USPSTF) recommended increasing mammography screening intervals for various age groups. In addition, ACS does not recommend clinical breast examination (CBE) for routine screening among average-risk women. Our study explores women's attitudes regarding screening mammography and CBE and evaluates the impact of the updated USPSTF and ACS guidelines on these attitudes. MATERIALS AND METHODS: Six hundred fourteen patients presenting to Mayo Clinic, Arizona and Minnesota, in July 2016 completed a self-administered survey, which included a summary of the updated guidelines. RESULTS: A majority of the 555 women who fit the inclusion criteria reported that CBE and mammogram are useful in detecting breast cancer and should be performed annually, and 51% of participants were unaware of the updated guidelines. Before reviewing the guidelines, 77% believed yearly CBE and 76% believed yearly mammogram was needed for routine screening. After reviewing the guidelines, the percentage of women who planned to continue with yearly CBE and mammogram decreased significantly to 61% and 64%, respectively (p < 0.001 and p < 0.001). Nearly half the participants (48%) believed the most influential reason for the guideline change was to decrease healthcare spending. CONCLUSION: Breast cancer screening is well received among patients, and a majority of surveyed women were unaware of recent guideline changes. After reviewing the guidelines, there was a significant downward shift in intended screening frequency, although the majority still planned to undergo annual screening. Informing women about updated evidence-based guidelines may influence their knowledge, preferences, and opinions.


Assuntos
Neoplasias da Mama/diagnóstico , Detecção Precoce de Câncer/normas , Conhecimentos, Atitudes e Prática em Saúde , Adulto , Comitês Consultivos , Fatores Etários , Idoso , American Cancer Society , Arizona , Estudos Transversais , Feminino , Humanos , Mamografia/normas , Programas de Rastreamento/normas , Pessoa de Meia-Idade , Minnesota , Inquéritos e Questionários
8.
Surg Neurol Int ; 9: 254, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30637172

RESUMO

BACKGROUND: Spinal cord decompression after cervical spinal cord injury (SCI) is the standard of care. However, there is a lack of consensus regarding the optimal management of these injuries, including the role of traction and timing of surgery. Here, we report the safety/efficacy of ventral surgery without preoperative traction for intraoperative fracture reduction following acute cervical SCI. METHODS: We prospectively collected a series of patients who sustained acute traumatic subaxial cervical (C3-7) spine fractures between 2004 and 2016. Patients underwent anterior cervical decompression and fusion within 24 h of injury without the utilization of preoperative traction. RESULTS: Thirty-six patients (27 male, 9 female), averaging 35 years of age, sustained 25 motor-vehicle accidents, 4 sports-related injuries, and 7 falls. Fracture dislocations were seen in 26 patients, whereas burst fractures were seen in 10. The majority of injuries occurred at the C4-5 (13 patients) and C5-6 (13 patients) levels. Complete SCI occurred in 10 patients, and incomplete SCI in 26 patients. All patients underwent anterior surgery only; 16 required vertebrectomy in addition to anterior cervical discectomy and fusion. Intraoperative reduction was achieved in all patients using a Cobb elevator or distraction pins without the use of preanesthesia traction. There were no intraoperative complications. Postoperatively, there were one postoperative hematoma, two wound/hardware revisions, one subsequent posterior fusion, and one reoperation anteriorly after screw pullout. The average hospital length of stay was 10.6 days (range 1-39). CONCLUSION: Early direct surgical stabilization/fusion for acute SCI because of subaxial cervical spine fractures is both safe and effective in selected cases when performed anteriorly without preoperative traction in select cases.

9.
Prev Med ; 94: 60-64, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27856341

RESUMO

Routine pelvic examinations have been a fundamental part of the annual female examination. The 2014 American College of Physicians (ACP) guideline recommends against routine pelvic examinations in asymptomatic, nonpregnant, average-risk women. Our aim was to evaluate women's attitudes and beliefs about pelvic examinations and how knowledge of the new guidelines contributes to attitudes and beliefs. A descriptive cross-sectional study was performed using a self-administered written survey developed through literature review and pretested and revised on the basis of staff suggestions. Nonpregnant women age≥21years presenting to outpatient clinics at Mayo Clinic in Arizona or Mayo Clinic in Rochester, Minnesota, received the survey. After being asked about pelvic examination practices and beliefs, participants were informed of the ACP guideline, to determine effect on attitudes and beliefs. Demographic characteristics and pertinent medical history questions were collected from participants. In total, 671 women who were predominantly white, married, and educated completed surveys. Participants described pelvic examinations as reassuring, and a majority believed the examinations were useful in detecting ovarian cancer (74.6%), necessary for screening for sexually transmitted infections (STIs) (71.0%), or necessary before initiating contraception (67.0%). After reading the 2014 ACP guideline, significantly fewer women planned to continue yearly pelvic examinations (P<0.001). Despite evidence to the contrary, women believed pelvic examinations were necessary for STI screening, contraception initiation, and ovarian cancer detection. After education on the ACP screening guideline, fewer women planned to continue yearly pelvic examinations.


Assuntos
Guias como Assunto , Exame Ginecológico , Conhecimentos, Atitudes e Prática em Saúde , Adulto , Anticoncepção/estatística & dados numéricos , Estudos Transversais , Feminino , Humanos , Programas de Rastreamento , Pessoa de Meia-Idade , Neoplasias Ovarianas/prevenção & controle , Infecções Sexualmente Transmissíveis/prevenção & controle , Inquéritos e Questionários , Estados Unidos , Neoplasias do Colo do Útero/prevenção & controle , Saúde da Mulher
10.
Oncotarget ; 7(20): 29689-707, 2016 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-27102439

RESUMO

Receptor tyrosine kinases-based autocrine loops largely contribute to activate the MAPK and PI3K/AKT pathways in melanoma. However, the molecular mechanisms involved in generating these autocrine loops are still largely unknown. In the present study, we examine the role of the transcription factor RUNX2 in the regulation of receptor tyrosine kinase (RTK) expression in melanoma. We have demonstrated that RUNX2-deficient melanoma cells display a significant decrease in three receptor tyrosine kinases, EGFR, IGF-1R and PDGFRß. In addition, we found co-expression of RUNX2 and another RTK, AXL, in both melanoma cells and melanoma patient samples. We observed a decrease in phosphoAKT2 (S474) and phosphoAKT (T308) levels when RUNX2 knock down resulted in significant RTK down regulation. Finally, we showed a dramatic up regulation of RUNX2 expression with concomitant up-regulation of EGFR, IGF-1R and AXL in melanoma cells resistant to the BRAF V600E inhibitor PLX4720. Taken together, our results strongly suggest that RUNX2 might be a key player in RTK-based autocrine loops and a mediator of resistance to BRAF V600E inhibitors involving RTK up regulation in melanoma.


Assuntos
Comunicação Autócrina/fisiologia , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Regulação Neoplásica da Expressão Gênica/fisiologia , Melanoma/metabolismo , Receptores Proteína Tirosina Quinases/biossíntese , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/fisiologia , Humanos
11.
Biopolymers ; 96(1): 4-13, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-20235194

RESUMO

Osteogenesis imperfecta (OI), a disorder characterized by fragile bones, is often a consequence of missense mutations in type I collagen, which change one Gly in the repeating (Gly-Xaa-Yaa)(n) sequence to a larger amino acid. The impact of local environment and the identity of the residue replacing Gly were investigated using two sets of triple-helical peptides. Gly mutations in the highly stable (Pro-Hyp-Gly)(10) system are compared with mutations in T1-865 peptides where the mutation is located within a less stable natural collagen sequence. Replacement of a Gly residue by Ala, Ser, or Arg leads to significant triple-helical destabilization in both peptide systems. The loss of stability (ΔT(m) ) due to a Gly to Ala or Gly to Ser change was greater in the more rigid (Pro-Hyp-Gly)(10) peptides than in the T1-865 set, as expected. But the final T(m) values, which may be the more biologically meaningful parameters, were higher for the (Pro-Hyp-Gly)(10) mutation peptides than for the corresponding T1-865 mutation peptides. In both peptide environments, a Gly to Arg replacement prevented the formation of a fully folded triple-helix. Monitoring of folding by differential scanning calorimetry showed a lower stability species as well as the fully folded triple-helical molecules for T1-865 peptides with Gly to Ala or Ser replacements, and this lower stability species disappears as a function of time. The difficulty in propagation through a mutation site in T1-865 peptides may relate to the delayed folding seen in OI collagens and indicates a dependence of folding mechanism on the local sequence environment.


Assuntos
Colágeno Tipo I/química , Colágeno Tipo I/genética , Mutação , Dobramento de Proteína , Sequência de Aminoácidos , Substituição de Aminoácidos , Arginina/química , Arginina/genética , Varredura Diferencial de Calorimetria , Dicroísmo Circular , Glicina/química , Glicina/genética , Humanos , Dados de Sequência Molecular , Osteogênese Imperfeita/genética , Osteogênese Imperfeita/metabolismo , Peptídeos/química , Conformação Proteica , Estabilidade Proteica , Estrutura Secundária de Proteína , Desdobramento de Proteína , Termodinâmica
12.
Biophys Chem ; 141(2-3): 222-30, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19251353

RESUMO

The influence of proteins and solutes on hysteresis of freezing and melting of water was measured by infrared (IR) spectroscopy. Of the solutes examined, poly-L-arginine and flounder antifreeze protein produced the largest freezing point depression of water, with little effect on the melting temperature. Poly-L-lysine, poly-L-glutamate, cytochrome c and bovine serum albumin had less effect on the freezing of water. Small compounds used to mimic non-polar (trimethylamine N-oxide, methanol), positively charged (guanidinium chloride, NH(4)Cl, urea) and negatively charged (Na acetate) groups on protein surfaces were also examined. These molecules and ions depress water's freezing point and the melting profiles became broad. Since infrared absorption measures both bulk solvent and solvent bound to the solutes, this result is consistent with solutes interacting with liquid water. The amide I absorption bands of antifreeze protein and poly-L-arginine do not detectably change with the phase transition of water. An interpretation is that the antifreeze protein and poly-L-arginine order liquid water such that the water around the group is ice-like.


Assuntos
Proteínas Anticongelantes/química , Proteínas/química , Água/química , Cloreto de Amônio/química , Animais , Bovinos , Citocromos c/química , Linguado , Congelamento , Ácido Glutâmico/química , Guanidina/química , Metanol/química , Metilaminas/química , Peptídeos/química , Polilisina/química , Soroalbumina Bovina/química , Acetato de Sódio/química , Espectrofotometria Infravermelho , Temperatura , Temperatura de Transição , Ureia/química
13.
J Clin Aesthet Dermatol ; 2(2): 26-31, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20967178

RESUMO

Mycetoma is a chronic and progressive subcutaneous granulomatous infection characterized by painless swelling and tumefaction, draining sinus tracts, and purulent discharge. The term eumycetoma is used to describe an infection caused by fungi, while an actinomycetoma is used to describe an infection caused by filamentous bacteria. An accurate identification of the pathogen plays a vital role in the treatment plan as well as a positive outcome for the patient. In this report, we present an elderly white female with an initial presentation of mycetoma masquerading as a squamous cell carcinoma. We also review microbiology, diagnostic modalities, and treatment for mycetoma.

14.
J Am Chem Soc ; 129(25): 7877-84, 2007 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-17550251

RESUMO

X-ray crystallography of collagen model peptides has provided high-resolution structures of the basic triple-helical conformation and its water-mediated hydration network. Vibrational spectroscopy provides a useful bridge for transferring the structural information from X-ray diffraction to collagen in its native environment. The vibrational mode most useful for this purpose is the amide I mode (mostly peptide bond C=O stretch) near 1650 cm-1. The current study refines and extends the range of utility of a novel simulation method that accurately predicts the infrared (IR) amide I spectral contour from the three-dimensional structure of a protein or peptide. The approach is demonstrated through accurate simulation of the experimental amide I contour in solution for both a standard triple helix, (Pro-Pro-Gly)10, and a second peptide with a Gly --> Ala substitution in the middle of the chain that models the effect of a mutation in the native collagen sequence. Monitoring the major amide I peak as a function of temperature gives sharp thermal transitions for both peptides, similar to those obtained by circular dichroism spectroscopy, and the Fourier transform infrared (FTIR) spectra of the unfolded states were compared with polyproline II. The simulation studies were extended to model early stages of thermal denaturation of (Pro-Pro-Gly)10. Dihedral angle changes suggested by molecular dynamics simulations were made in a stepwise fashion to generate peptide unwinding from each end, which emulates the effect of increasing temperature. Simulated bands from these new structures were then compared to the experimental bands obtained as temperature was increased. The similarity between the simulated and experimental IR spectra lends credence to the simulation method and paves the way for a variety of applications.


Assuntos
Colágeno/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Colágeno/genética , Colágeno/metabolismo , Conformação Proteica , Dobramento de Proteína , Temperatura
15.
J Biol Chem ; 281(48): 36937-43, 2006 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-16998200

RESUMO

Missense mutations in the collagen triple helix that replace one Gly residue in the (Gly-X-Y)(n) repeating pattern by a larger amino acid have been shown to delay triple helix folding. One hypothesis is that such mutations interfere with the C- to N-terminal directional propagation and that the identity of the residues immediately N-terminal to the mutation site may determine the delay time and the degree of clinical severity. Model peptides are designed to clarify the role of tripeptide sequences N-terminal to the mutation site, with respect to length, stability, and nucleation propensity, to complete triple helix folding. Two sets of peptides with different N-terminal sequences, one with the natural sequence alpha1(I) 886-900, which is just adjacent to the Gly(901) mutation, and one with a GPO(GAO)(3) sequence, which occurs at alpha1(I) 865-879, are studied by CD and NMR. Placement of the five tripeptides of the natural alpha1(I) collagen sequence N-terminal to the Gly to Ala mutation site results in a peptide that is folded only C-terminal to the mutation site. In contrast, the presence of the Hyp-rich sequence GPO(GAO)(3) N-terminal to the mutation allows complete refolding in the presence of the mutation. The completely folded peptide contains an ordered central region with unusual hydrogen bonding while maintaining standard triple helix structure at the N- and C-terminal ends. These peptide results suggest that the location and sequences of downstream regions favorable for renucleation could be the key factor in the completion of a triple helix N-terminal to a mutation.


Assuntos
Colágeno/química , Glicina/química , Peptídeos/química , Sequência de Aminoácidos , Sítios de Ligação , Dicroísmo Circular , Colágeno Tipo I/química , Cadeia alfa 1 do Colágeno Tipo I , Humanos , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Mutação , Desnaturação Proteica , Dobramento de Proteína , Estrutura Secundária de Proteína , Homologia de Sequência de Aminoácidos
16.
J Biol Chem ; 281(44): 33283-90, 2006 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-16963782

RESUMO

Interest in self-association of peptides and proteins is motivated by an interest in the mechanism of physiologically higher order assembly of proteins such as collagen as well as the mechanism of pathological aggregation such as beta-amyloid formation. The triple helical form of (Pro-Hyp-Gly)(10), a peptide that has proved a useful model for molecular features of collagen, was found to self-associate, and its association properties are reported here. Turbidity experiments indicate that the triple helical peptide self-assembles at neutral pH via a nucleation-growth mechanism, with a critical concentration near 1 mM. The associated form is more stable than individual molecules by about 25 degrees C, and the association is reversible. The rate of self-association increases with temperature, supporting an entropically favored process. After self-association, (Pro-Hyp-Gly)(10) forms branched filamentous structures, in contrast with the highly ordered axially periodic structure of collagen fibrils. Yet a number of characteristics of triple helix assembly for the peptide resemble those of collagen fibril formation. These include promotion of fibril formation by neutral pH and increasing temperature; inhibition by sugars; and a requirement for hydroxyproline. It is suggested that these similar features for peptide and collagen self-association are based on common lateral underlying interactions between triple helical molecules mediated by hydrogen-bonded hydration networks involving hydroxyproline.


Assuntos
Colágeno/química , Colágeno/metabolismo , Varredura Diferencial de Calorimetria , Metabolismo dos Carboidratos , Colágeno/ultraestrutura , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Transmissão , Peptídeos/química , Peptídeos/metabolismo , Temperatura
17.
Int J Oncol ; 23(5): 1365-71, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14532978

RESUMO

A disintegrin and metalloproteases (ADAMs) are proteins that contain both a disintegrin and metalloprotease domain and have potential implications for the metastasis of human cancer cells via cell adhesion and protease activities. In this study, we analyzed the expression levels of ADAM-9, ADAM-10 and ADAM-17 (TNF-alpha converting enzyme, TACE), and TIMP-3 (tissue inhibitor of metalloproteinase-3) in human prostatic tumor cell lines as well as in clinical patient materials (BPH and tumor tissue samples). Human prostatic tumor cell lines (MDA PCa 2b, LNCaP-C33, -C51, -C81, -Pro5, -Ln3, -C4-2, PC3, and DU145) showed varied levels of expression for ADAM-9, -10 and -17 mRNA. A strong expression of ADAM-17/TACE was further revealed by Western blot analysis in prostatic tumor cell lines. In the case of clinical material, all the tumor samples (8/8) revealed the expression of ADAM-9, -10, and -17 compared to the specimens of benign prostatic hyperplasia (BPH) where 80% of (8/10) samples showed the expression of ADAM-9, 86% (6/7) of ADAM-10, and 30% (3/10) of ADAM-17/TACE. Interestingly, expression of a potent inhibitor of ADAM-17 (TIMP-3) was not detected in any prostatic tumor cell lines (0/9), while TIMP-3 expression was detected in 82% (9/11) of BPH samples. Androgen-sensitive LNCaP-C33 cells exhibited differences in ADAMs regulation by 5alpha-dihydrotestosterone (DHT), while such differences were not detectable in androgen-independent LNCaP-C81 cells. These results suggest that an inverse expression pattern of ADAM-17/TACE and TIMP-3, and the regulation of ADAMs with DHT might play an important role in the pathogenesis of prostate cancer.


Assuntos
Adenocarcinoma/enzimologia , Desintegrinas/biossíntese , Proteínas de Membrana/biossíntese , Metaloendopeptidases/biossíntese , Neoplasias da Próstata/enzimologia , Inibidores Teciduais de Metaloproteinases/biossíntese , Proteínas ADAM , Proteína ADAM10 , Proteína ADAM17 , Secretases da Proteína Precursora do Amiloide , Animais , Northern Blotting , Western Blotting , Divisão Celular , Linhagem Celular Tumoral , Di-Hidrotestosterona/farmacologia , Humanos , Masculino , Camundongos , Camundongos Nus , Metástase Neoplásica , Transplante de Neoplasias , Hiperplasia Prostática/patologia , Estrutura Terciária de Proteína , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Inibidor Tecidual de Metaloproteinase-3 , Regulação para Cima
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