RESUMO
The isomer depletion of ^{93m}Mo was recently reported [Chiara et al., Nature (London) 554, 216 (2018)NATUAS0028-083610.1038/nature25483] as the first direct observation of nuclear excitation by electron capture (NEEC). However, the measured excitation probability of 1.0(3)% is far beyond the theoretical expectation. In order to understand the inconsistency between theory and experiment, we produce the ^{93m}Mo nuclei using the ^{12}C(^{86}Kr,5n) reaction at a beam energy of 559 MeV and transport the reaction residues to a detection station far away from the target area employing a secondary beam line. The isomer depletion is expected to occur during the slowdown process of the ions in the stopping material. In such a low γ-ray background environment, the signature of isomer depletion is not observed, and an upper limit of 2×10^{-5} is estimated for the excitation probability. This is consistent with the theoretical expectation. Our findings shed doubt on the previously reported NEEC phenomenon and highlight the necessity and feasibility of further experimental investigations for reexamining the isomer depletion under low γ-ray background.
RESUMO
Chemosensory proteins (CSPs) have been considered to play a key role in chemoreception in insects. As stated in our earlier study, three CSP genes from rice leaf folder Cnaphalocrocis medinalis have been identified and showed potential physiological functions in olfaction. Here, we conducted western blot, immunolocalization, competitive binding assay and knockdown assay by RNA interference both in vitro and in vivo to reveal the functions of these three CSPs in C. medinalis. Results showed that both CmedCSP1 and CmedCSP2 are housed in sensilla basiconica and showed high binding affinities to a wide range of host-related semiochemicals. On the other hand, CmedCSP3 is highly expressed in sensilla trichodea of males and sensilla basiconica of females. It showed binding affinities to plant volatiles, especially terpenoids, as well as two of the C. medinalis sex pheromone components, Z11-16:Ac and Z11-16:Al. The transcript expression level of the three CSP genes significantly decreased after injecting target double-stranded RNAs and resulted in remarkably down-regulation on electroantennogram responses evoked by host-related semiochemicals and one sex pheromone compound, which have high binding affinities with CmedCSPs. In conclusion, the three CmedCSPs tested are involved in C. medinalis reception of semiochemicals, including host attractants and sex pheromones.
Assuntos
Proteínas de Insetos/metabolismo , Mariposas/metabolismo , Sensilas/metabolismo , Atrativos Sexuais/metabolismo , Olfato , Animais , Feminino , Proteínas de Insetos/isolamento & purificação , Masculino , Interferência de RNARESUMO
Insulin-like peptides (ILPs) act through a conserved insulin signaling pathway and play crucial roles in insect metabolism, growth, reproduction, and aging. Application of bovine insulin is able to increase vitellogenin (Vg) mRNA and protein levels in female insects. Here, we first show that injection of bovine insulin into previtellogenic Chrysopa septempunctata female adults promoted ovarian growth, increased Vg protein abundance, elevated reproductive performance, and enhanced protease activity. These data suggested that ILPs play crucial roles in reproductive regulation of the green lacewing, C. septempunctata.
Assuntos
Proteínas de Insetos/metabolismo , Insetos/fisiologia , Insulina/metabolismo , Oviposição/efeitos dos fármacos , Animais , Bovinos , Feminino , Proteínas de Insetos/administração & dosagem , Insetos/efeitos dos fármacos , Insulina/administração & dosagem , Peptídeo Hidrolases/metabolismo , Peptídeos/administração & dosagem , Peptídeos/metabolismo , Controle Biológico de Vetores , Vitelogênese/efeitos dos fármacos , Vitelogeninas/metabolismoRESUMO
It is well known that the odorant-binding proteins (OBPs) play crucial roles in insect olfactory detection. To explore if interactions of OBPs affect olfactory coding in the rice leaffolder Cnaphalocrocis medinalis ligand-binding experiments, molecular docking, RNA interference and electrophysiological recording were performed. The binding activity of two C. medinalis OBPs (CmedOBPs) to rice plant volatiles showed wide flexibility depending on the structure of ligands and interactions of CmedOBPs involved. The binding sites of CmedOBP2 and CmedOBP3 to rice plant volatiles were well predicted by three-dimensional structure modelling and molecular docking experiments. In addition, the interactions of these two CmedOBPs in the perception of rice volatiles were demonstrated by RNA interference experiments. When a single double-stranded RNA (dsRNA)-CmedOBP2 was injected, the expression of CmedOBP2 was significantly reduced and the expression of CmedOBP3 was significantly increased, and vice versa. When both dsRNA-CmedOBP2 and 3 were injected together, greater reduction of electroantennogram responses to rice plant volatiles was induced than that seen with individual injection of either dsRNA-CmedOBP2 or dsRNA-CmedOBP3. These results clearly indicate that the interactions of CmedOBP2 and CmedOBP3 have significant effects on C. medinalis during the detection of host plant volatiles.
Assuntos
Antenas de Artrópodes/fisiologia , Proteínas de Insetos/genética , Mariposas/fisiologia , Percepção Olfatória , Receptores Odorantes/genética , Animais , Quimiotaxia , Feminino , Proteínas de Insetos/metabolismo , Masculino , Simulação de Acoplamento Molecular , Mariposas/genética , Interferência de RNA , RNA de Cadeia Dupla/metabolismo , Receptores Odorantes/metabolismoRESUMO
Pheromone-binding proteins (PBPs) are believed to be involved in the recognition of semiochemicals. In the present study, western blot analysis, fluorescence-binding characteristics and immunolocalization of CmedPBP4 from the rice leaffolder, Cnaphalocrocis medinalis, were investigated. Western blot analysis revealed that CmedPBP4 showed obvious antenna-specific expression patterns in female and male antenna, and made a clearly different sex-biased expression. Immunocytochemical labeling revealed that CmedPBP4 showed specific expression in the trichoid sensilla. Competitive fluorescence binding assays indicated that CmedPBP4 could selectively recognize three sex pheromone components (Z13-18:Ac, Z11-16:Al and Z13-18:OH) and eleven rice plant volatiles, including cyclohexanol, nerolidol, cedrol, dodecanal, ionone, (-)-α-cedrene, (Z)-farnesene, ß-myrcene, R-(+)-limonene, (-)-limonene, and (+)-3-carene. Meanwhile the CmedPBP4 detection of sex pheromones and host odorants was pH-dependent. Our results, for the first time, provide further evidence that trichoid sensilla might be play an important role in detecting sex pheromones and host plant volatiles in the C. medinalis moth. Our systematic studies provided further detailed evidence for the function of trichoid sensilla in insect semiochemical perception.
Assuntos
Proteínas de Transporte/fisiologia , Proteínas de Insetos/fisiologia , Mariposas/metabolismo , Comunicação Animal , Animais , Antenas de Artrópodes/metabolismo , Western Blotting , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Expressão Gênica , Imuno-Histoquímica , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Mariposas/fisiologia , Sensilas/fisiologia , Estimulação QuímicaRESUMO
BACKGROUND: Intakes of choline and betaine have been inversely related to the risk of various neoplasms, but scant data exist on nasopharyngeal carcinoma (NPC). We examined the association between consumption of choline and betaine and risk of NPC. METHODS: We conducted a case-control study with 600 incident NPC patients and 600 controls 1 : 1 matched by age, sex and household type in Guangdong, China. Dietary intake was assessed by a food frequency questionnaire through face-to-face interview. RESULTS: Intakes of total choline, betaine and choline+betaine were inversely related to NPC after adjustment for various lifestyle and dietary factors (all P-trend <0.001). Adjusted odds ratios (95% CI) for quartile 4 (vs quartile 1) were 0.42 (0.29, 0.61) for total choline, 0.50 (0.35, 0.72) for betaine and 0.44 (0.30, 0.64) for betaine+total choline. Regarding various sources of choline, lower NPC risk was associated with greater intakes of choline from phosphatidylcholine, free choline, glycerophosphocholine and phosphocholine, but not sphingomyelin. CONCLUSION: These findings are consistent with a beneficial effect of choline and betaine intakes on carcinogenesis.
Assuntos
Betaína/administração & dosagem , Colina/administração & dosagem , Neoplasias Nasofaríngeas/dietoterapia , Neoplasias Nasofaríngeas/patologia , Adulto , Idoso , Carcinogênese/efeitos dos fármacos , Carcinoma , Estudos de Casos e Controles , China , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/epidemiologia , Fatores de Risco , Inquéritos e QuestionáriosRESUMO
UNLABELLED: This case-control study compared the associations of four widely used diet-quality scoring systems with the risk of hip fractures and assessed their utility in elderly Chinese. We found that individuals avoiding a low-quality diet have a lower risk of hip fractures in elderly Chinese. INTRODUCTION: Few studies examined the associations of diet-quality scores on bone health, and no studies were available in Asians and compared their validity and utility in a study. We assessed the associations and utility of four widely used diet-quality scoring systems with the risk of hip fractures. METHODS: A case-control study of 726 patients with hip fractures (diagnosed within 2 weeks) aged 55-80 years and 726 age- (within 3 years) and gender-matched controls was conducted in Guangdong, China (2009-2013). Dietary intake was assessed using a 79-item food frequency questionnaire with face-to-face interviews, and the Healthy Eating Index-2005 (HEI-2005, 12 items), the alternate Healthy Eating Index (aHEI, 8 items), the Diet Quality Index-International (DQI-I, 17 items), and the alternate Mediterranean Diet Score (aMed, 9 items) (the simplest one) were calculated. RESULTS: All greater values of the diet-quality scores were significantly associated with a similar decreased risk of hip fractures (all p trends <0.001). The multivariate-adjusted odds ratios (ORs) and 95% confidential intervals (95% CIs) comparing the extreme groups of diet-quality scores were 0.29 (0.18, 0.46) (HEI-2005), 0.20 (0.12, 0.33) (aHEI), 0.25 (0.16, 0.39) (DQI-I), and 0.28 (0.18, 0.43) (aMed) in total subjects; and the corresponding ORs ranged from 0.04 to 0.27 for men and from 0.26 to 0.44 for women (all p trends <0.05), respectively. CONCLUSIONS: Avoiding a low-quality diet is associated with a lower risk of hip fractures, and the aMed score is the best scoring system due to its equivalent performance and simplicity for the user.
Assuntos
Dieta/normas , Fraturas do Quadril/etiologia , Fraturas por Osteoporose/etiologia , Idoso , Estudos de Casos e Controles , China/epidemiologia , Dieta/efeitos adversos , Dieta/estatística & dados numéricos , Inquéritos sobre Dietas , Dieta Mediterrânea/estatística & dados numéricos , Comportamento Alimentar , Feminino , Fraturas do Quadril/epidemiologia , Fraturas do Quadril/prevenção & controle , Humanos , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Fraturas por Osteoporose/epidemiologia , Fraturas por Osteoporose/prevenção & controle , Medição de Risco/métodos , Fatores Sexuais , Fatores SocioeconômicosRESUMO
Objective: To comprehensively understand the disease burden of liver cirrhosis and other chronic liver diseases caused by alcohol use in China from 1990 to 2019, as well as to predict the trends in disease burden from 2020 to 2030. Methods: The analysis utilized data from the Global Burden of Disease study in 2019 (GBD2019). Key indicators such as incidence rate, mortality rate, disability-adjusted life years (DALY), years of life lost due to premature mortality, and years lived with disability were selected to describe the disease burden of alcohol-related liver cirrhosis and other chronic liver diseases in China from 1990 to 2019. The estimated annual percentage change (EAPC) was used to depict the temporal trends in disease burden. Furthermore, a Bayesian age-period-cohort (BAPC) model was constructed using R software to predict the age-standardized incidence rate (ASIR) and age-standardized mortality rate (ASMR) of alcohol-related liver cirrhosis and other chronic liver diseases in China from 2020 to 2030. Results: From 1990 to 2019, the incidence of alcohol-related liver cirrhosis and other chronic liver diseases in China showed an upward trend, with an EAPC of 0.31% (95%CI: 0.10%-0.52%). However, the DALY declined, with an EAPC of -2.81% (95%CI: -2.92% - -2.70%). The ASMR showed a downward trend, with an EAPC of -2.55% (95%CI: -2.66% - -2.45%). The highest incidence of cirrhosis of liver caused by alcohol and other chronic liver diseases was reported in the age group of 35-49 years, while the ASMR increased gradually with age, with a significant rise after the age of 30. The age-standardized DALY rate peaked between the ages of 55 and 64. The disease burden indicators for males were consistently higher than those for females during the same period. According to the predictions of the BAPC model, from 2020 to 2030, the ASIR for cirrhosis of liver caused by alcohol and other chronic liver diseases in the entire population of China was projected to increase from 3.45/100 000 in 2020 to 3.78/100 000 in 2030, a growth of 9.57%. Conversely, the ASMR was expected to decrease from 1.45/100 000 in 2020 to 1.24/100 000 in 2030, a reduction of 14.48%. Conclusions: The disease burden of cirrhosis of liver caused by alcohol and other chronic liver diseases remained serious in China, especially in men and the middle-aged to elderly population. There is a pressing need to prioritize attention and resources towards these groups. Despite the projected decrease in ASMR, the ASIR continued to rise and is expected to persist in its upward trend until 2030.
Assuntos
Cirrose Hepática Alcoólica , Cirrose Hepática , Feminino , Masculino , Pessoa de Meia-Idade , Idoso , Humanos , Adulto , Teorema de Bayes , Cirrose Hepática/epidemiologia , Cirrose Hepática Alcoólica/epidemiologia , Efeitos Psicossociais da Doença , Etanol , China/epidemiologia , Carga Global da Doença , Incidência , Anos de Vida Ajustados por Qualidade de VidaRESUMO
Objective: To examine the burden and trends of acute viral hepatitis in Guangdong Province from 1990 to 2019, and provide reference evidences for hepatitis prevention and control in the province. Methods: Data on acute viral hepatitis (hepatitis A, B, C, and E) in Guangdong from 1990 to 2019 were extracted from the Global Burden of Disease Study 2019 database. The incidence, prevalence, mortality, and disability-adjusted life years (DALY) data were analyzed by age and gender, and the estimated annual percentage change (EAPC) was calculated to describe the changing trends in disease burden. Results: From 1999 to 2019, the standardized incidence, prevalence, mortality, and DALY of acute viral hepatitis in Guangdong were higher than the national averages. In 2019, 51.43% (2 245 087/4 365 221) of acute viral hepatitis cases in Guangdong Province were mainly attributed to hepatitis B, and 77.18% (106/138) of deaths were due to acute hepatitis B. In different age groups, except for acute hepatitis B, which was more common in adults, the incidence rates of other types of viral hepatitis such as hepatitis A, B, and E showed an overall decreasing trend with age. The mortality rates of different types of acute viral hepatitis, except for the <5 age group, increased with age. The overall incidence and mortality rates of acute viral hepatitis were higher in men than in women. Conclusions: The overall burden of acute viral hepatitis in Guangdong declined in 2019, but remained higher than the national level. Further efforts are needed to strengthen hepatitis prevention and screening in different population in Guangdong Province, especially in children and the elderly.
Assuntos
Hepatite A , Hepatite B , Adulto , Masculino , Criança , Humanos , Feminino , Idoso , Hepatite A/epidemiologia , Efeitos Psicossociais da Doença , Hepatite B/epidemiologia , Incidência , China/epidemiologia , Carga Global da Doença , Anos de Vida Ajustados por Qualidade de VidaRESUMO
AIM: The study aimed to understand better the somatic mutations in the human MutL Homolog 1 (hMLH1) and human MutS Homolog 2 (hMSH2) genes in colorectal cancer (CRC) and to investigate the differences derived from ethnicity, family history, detection method and microsatellite instability (MSI). METHOD: The terms 'hMSH2' or 'hMLH1' and 'colorectal cancer' 'colorectal carcinoma' or 'colorectal tumour' were searched in the PubMed, Springer, Lippincott, Williams & Wilkins and HighWire Press databases for the publication period December 1993 to September 2010. The Comprehensive Meta Analysis V2 software (Biostat Inc.) was used to explore the prevalence and 95% confidence intervals. RESULTS: The prevalence of somatic mutations in the hMLH1 and hMSH2 genes in CRC was 0.15 (95% CI 0.10-0.22) and 0.10 (95% CI 0.07-0.16), respectively. A higher prevalence of somatic mutations in hMSH2 was found in hereditary non-polyposis CRC than in sporadic CRC: 0.36 (95% CI 0.14-0.67) and 0.10 (95% CI 0.07-0.13) respectively. In addition, a higher prevalence of somatic mutations in the hMLH1 gene was observed relative to hMSH2 in the European group. The prevalence was higher in the high-level instability (MSI-H) group than in both the low-level instability (MSI-L) and the microsatellite stable (MSS) groups. CONCLUSION: Somatic mutations in the hMLH1 and hMSH2 genes play a vital role in CRC and a high prevalence was found in this meta-analysis. Furthermore, more studies are needed which focus on somatic mutations in the American population and in patients with MSI-L and MSS.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Neoplasias Colorretais/genética , Proteína 2 Homóloga a MutS/genética , Mutação , Proteínas Nucleares/genética , Ásia , Neoplasias Colorretais/etnologia , Europa (Continente) , Marcadores Genéticos , Humanos , Instabilidade de Microssatélites , Proteína 1 Homóloga a MutL , América do NorteRESUMO
OBJECTIVES: To estimate the prevalence of type 2 diabetes and impaired glucose tolerance (IGT), and to identify potential risk factors among adults in rural areas in North China. STUDY DESIGN: Multistage random cluster sampling in a cross-sectional study. METHODS: Data were collected in 2005 from 1058 adults aged >20 years. Body mass index (BMI), waist and hip circumferences, 2-hour postprandial glucose (2-hPG) and other data were collected. RESULTS: The prevalence of diabetes and IGT was higher for both men and women in the study group compared with the national averages (diabetes: 7.17% and 7.01%, respectively; IGT: 7.55% and 7.95%, respectively). Men aged ≥60 years and women aged 50-59 years had the highest prevalence of diabetes compared with other age groups (9.62% and 9.21% respectively). Both men and women aged ≥60 years had the highest prevalence of IGT. A sudden increase in 2-hPG level was seen in women aged ≥40 years. Those with BMI ≥28 kg/m(2) were at two-fold higher risk than normal. The risk for glucose tolerance abnormalities was almost 1.55-fold higher in subjects with waist/height ratio (WHtR) ≥0.50. The odds ratio for diabetes was 0.32 (95% confidence interval 0.10-0.98) in subjects with an annual family income ≥30,000 yuan compared with those with lower incomes. CONCLUSIONS: These results indicate that rural populations in North China have a higher prevalence of type 2 diabetes and IGT compared with national averages. Women aged ≥40 years warrant more attention to avoid glucose tolerance abnormalities. BMI and WHtR are predictive of the prevalence of glucose tolerance abnormalities. High annual family income appears to be a protective factor for type 2 diabetes.
Assuntos
Diabetes Mellitus Tipo 2/epidemiologia , Intolerância à Glucose/epidemiologia , População Rural/estatística & dados numéricos , Adulto , Fatores Etários , Índice de Massa Corporal , Pesos e Medidas Corporais , China/epidemiologia , Estudos Transversais , Feminino , Teste de Tolerância a Glucose , Comportamentos Relacionados com a Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Fatores Sexuais , Fatores SocioeconômicosRESUMO
Objective:To discuss the correlation between adenoid hypertrophy and laryngopharyngeal reflux in children, and to determine the accuracy of reflux symptom index(RSI) and reflux finding score(RFS) in predicting adenoid hypertrophy and laryngopharyngeal reflux(LPR). Method:Assessment of RSI and RFS was performed in 71 children with adenoid hypertrophy who underwent surgery.The adenoid biopsy specimens were examined by pepsin immunohistochemical staining. According to the positive results of pepsin staining to evaluate the sensitivity and specificity of RSI and RFS to predict LPR. Result:Among the 71 children with adenoid hypertrophy, RSI was greater than 13 points in 4 cases (5.63%), RFS was greater than 7 points in 26 cases (36.62%), and 1(1.41%) was positive in both scores. Pepsin expression was detected in 52 cases of adenoid hypertrophy tissues, with a total positive rate of 73.24% (52/71),most were strong positiveï¼15/71,21.13%ï¼and positiveï¼23/71,32.39%ï¼. The higher the adenoid hypertrophy grade, the higher the expression level of pepsin (r=0.476, P<0.01).Define the positive rate of pepsin as the gold standard for the diagnosis of LPR, the sensitivity and specificity of RSI and RFS were 5.77%,34.62% and 94.74%,57.89% respectively. Pepsin staining intensity was positively correlated with troublesome or annoying coughï¼r=0.356, P=0.002ï¼and was negatively correlated with ventricular obliterationï¼r=ï¼0.212ï¼P=0.038ï¼. Conclusion:There is a correlation between adenoid hypertrophy and LPR in childrenï¼LPR plays an important role in the development of adenoid and the role and mechanism of pepsin in adenoid hypertrophy needs further studyAs the low sensitivity of RSI and RFS, it is not suitable for the screening of adenoid hypertrophy in children with LPR. Children with adenoid hypertrophy cough for a long time and the laryngoscopy shows the ventricular obliteration, the presence of LPR should be warned.
Assuntos
Tonsila Faríngea/patologia , Refluxo Laringofaríngeo/complicações , Criança , Humanos , Hipertrofia , Refluxo Laringofaríngeo/metabolismo , Laringoscopia , Pepsina A/metabolismoRESUMO
OBJECTIVE: To evaluate the relationship between pepsin induced by laryngopharyngeal reflux and laryngeal carcinoma. METHODS: Patients with vocal cord leukoplakia(n=18) and laryngeal carcinoma(n=21) encountered in Nanfang Hospital between December 2012 and April 2014 were included and sixteen healthy volunteers were recruited as control. Laryngeal biopsy specimens were taken from the patients with laryngeal carcinoma, or vocal cord leukoplakia and control subjects for the immunohistochemical study of pepsin. The correlation between pepsin expression and reflux events of 24 hour multichannel intraluminal impedance-pH monitoring (MII-pH) was analyzed. RESULTS: The patients with laryngeal carcinoma showed the highest expression of pepsin, followed by the patients with vocal cord leukoplakia and control subjects, with significant difference among the three groups (in strong positive expression, the constituent ratio of each group are 0/16ã1/18 and 4/21, P<0.01). The presence of pepsin was associated with upright and total laryngopharyngeal acid reflux (P<0.05), including acid reflux episodes, the percentage of times that the pH was below four, the percentages of acid reflux time and average acid removal time. There was a significant correlation between the pepsin level and the esophageal acid reflux parameters (P<0.05) except supine the percentage of time that the pH was below four. CONCLUSIONS: Pepsin expression in laryngeal tissue increases in patients with vocal cord leukoplakia and laryngeal carcinoma, contributing to the development of laryngopharyngeal carcinogenesis.
Assuntos
Carcinoma/metabolismo , Neoplasias Laríngeas/metabolismo , Refluxo Laringofaríngeo/metabolismo , Pepsina A/metabolismo , Carcinoma/etiologia , Estudos de Casos e Controles , Refluxo Gastroesofágico/metabolismo , Humanos , Neoplasias Laríngeas/etiologia , Refluxo Laringofaríngeo/complicações , Laringe/metabolismo , Leucoplasia/complicações , Leucoplasia/metabolismoRESUMO
Cataract formation in diabetic lenses has been attributed to polyol-osmotic pressure-generated influx of water. The ensuing swelling in the form of pocket and lake accumulations cause light scattering. The authors tested whether clear lenses of diabetic patients show different hydration properties than age matched normal lenses. Normal and diabetic human lenses were investigated for their nonfreezable water content by differential scanning calorimetry. The total water content of the lens sections were studied by thermogravimetric analysis. Non-cataractous diabetic lenses in all three regions showed a higher total water content than normal lenses. The nonfreezable water content, seems to increase with age in diabetic lenses and decrease with age in normal human lenses. Thus, hydration changes in human diabetic lenses precede cataract formation. While syneresis, the release of bound water into the bulk, is part of the normal aging process, it appears to occur in the younger diabetics only. In older diabetics syneresis is halted or even reversed. This may be due to the glycation of lens proteins in diabetic patients which tends to immobilize water and therefore, reverse the syneresis due to aging.
Assuntos
Água Corporal/metabolismo , Catarata/metabolismo , Diabetes Mellitus/metabolismo , Cristalino/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/metabolismo , Catarata/etiologia , Complicações do Diabetes , Congelamento , Humanos , Técnicas In Vitro , Pessoa de Meia-IdadeRESUMO
Two constructs of transgenic mice, TG61 and TG72, containing HIV-1 protease linked to lens alpha A-crystallin promoter develop cataract. The TG61 construct exhibits cataractogenesis in utero, while in the TG72 construct frank opacities appear 24 days (homozygotes) and 26 days (hemizygotes) after birth. Differential scanning calorimetry and thermogravimetric analysis studies indicate that the hydration of lenses is strongly correlated with cataractogenesis. In all clear lenses (normal and precataractous) the total water content was the same, 68%, and increased upon opacification. The bound water, measured as percentage nonfreezable water of the total water, decreased upon cataract formation, indicating a syneretic process. On the other hand, the bound water expressed as grams of nonfreezable water per gram dry weight increases upon opacification. This implies that proteolysis and subsequent enhanced hydration is the primary supramolecular event in cataractogenesis and that syneresis in the lens of transgenic mice is of secondary importance.