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INTRODUCTION: Person-centred care (PCC) has been recognized as a critical element in delivering quality and responsive health services. The patient-provider relationship, conceptualized at the core of PCC in multiple models, remains largely unexamined in HIV care. We conducted a systematic review to better understand the types of PCC interventions implemented to improve patient-provider interactions and how these interventions have improved HIV care continuum outcomes and person-reported outcomes (PROs) among people living with HIV in low- and middle-income countries. METHODS: We searched databases, conference proceedings and conducted manual targeted searches to identify randomized trials and observational studies published up to January 2023. The PCC search terms were guided by the Integrative Model of Patient-Centeredness by Scholl. We included person-centred interventions aiming to enhance the patient-provider interactions. We included HIV care continuum outcomes and PROs. RESULTS: We included 28 unique studies: 18 (64.3%) were quantitative, eight (28.6.%) were mixed methods and two (7.1%) were qualitative. Within PCC patient-provider interventions, we inductively identified five categories of PCC interventions: (1) providing friendly and welcoming services; (2) patient empowerment and improved communication skills (e.g. supporting patient-led skills such as health literacy and approaches when communicating with a provider); (3) improved individualized counselling and patient-centred communication (e.g. supporting provider skills such as training on motivational interviewing); (4) audit and feedback; and (5) provider sensitisation to patient experiences and identities. Among the included studies with a comparison arm and effect size reported, 62.5% reported a significant positive effect of the intervention on at least one HIV care continuum outcome, and 100% reported a positive effect of the intervention on at least one of the included PROs. DISCUSSION: Among published HIV PCC interventions, there is heterogeneity in the components of PCC addressed, the actors involved and the expected outcomes. While results are also heterogeneous across clinical and PROs, there is more evidence for significant improvement in PROs. Further research is necessary to better understand the clinical implications of PCC, with fewer studies measuring linkage or long-term retention or viral suppression. CONCLUSIONS: Improved understanding of PCC domains, mechanisms and consistency of measurement will advance PCC research and implementation.
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Países em Desenvolvimento , Infecções por HIV , Assistência Centrada no Paciente , Humanos , Infecções por HIV/terapia , Infecções por HIV/psicologia , Assistência Centrada no Paciente/métodos , Continuidade da Assistência ao Paciente , Relações Profissional-PacienteRESUMO
Despite growing interest in the use of cannabis for the treatment of cancer-related symptoms, there are limited studies that have assessed the use pattern, type, and mode of delivery of cannabis products used by cancer survivors. This study describes the current state of the use pattern, product type, and mode of delivery of cannabis used by cancer survivors. This was a cross-sectional study of cancer survivors from 41 U.S. states who received treatment at the largest NCI-designated comprehensive cancer center. The weighted prevalence of the use patterns, product types, and modes of delivery of cannabis used by cancer survivors was estimated. A total of 1886 cancer survivors were included in the study, with 915 (48% [95% CI: 45-51]) reporting ever using cannabis. Of survivors who had ever used cannabis, 36% (95% CI: 33-40) were current users. Among survivors who reported cannabis use after diagnosis, 40% used cannabis during and after cancer treatment, 35% used cannabis during treatment, and 25% used cannabis after completing their cancer treatment. Additionally, 48% of survivors reported an increase in cannabis use since cancer diagnosis. The commonest types of cannabis products used by cancer survivors were dry leaf cannabis (71%), cannabidiol (CBD) oil (46%), and cannabis candy (40%). Moreover, cancer survivors frequently used baked goods (32%), creams and gels (21%), and tinctures (18%). Furthermore, among ever users, the predominant mode of use was cannabis inhalation/smoking (69%) compared to eating/drinking (59%). More so, the common mode of inhalation/smoking of cannabis products were rolled cannabis cigarettes (79%), pipes (36%), water pipes (34%), vaporizers or vapes (14%), and e-cigarette devices (14%). A substantial number of cancer survivors use cannabis during cancer treatment, with increased use following cancer diagnosis. The forms and modes of delivery of cannabis varied among survivors, with most survivors inhaling or smoking cannabis. There is a need to educate healthcare providers (HCPs) and survivors on current evidence of cannabis use and strengthen cannabis regulatory frameworks to optimize benefits and minimize adverse events from cannabis use during cancer treatment.
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Expanding access to HPV vaccination is critical to increasing HPV vaccine uptake. We assessed the determinants and barriers to consistent offering of HPV vaccine among healthcare facilities. This was a cross-sectional survey of healthcare providers (HCPs) in Texas. Prevalence of the reasons healthcare practices do not consistently offer HPV vaccination was estimated. Multivariable regression analyses were conducted. Of 1169 HCPs included in the study, 47.5% (95% CI: 44.6-50.3%) reported their practices do not provide HPV vaccination or do not offer it consistently. Compared to physicians, nurses had 77% lower odds (Adjusted Odds Ratio (AOR): 0.23, 95% CI: 0.16-0.32, p-value: < .001), and physician assistants had 89% lower odds (AOR: 0.11, 95% CI: 0.07-0.16, p-value: < .001) of their healthcare practices consistently offering HPV vaccination. Compared to university/teaching hospitals, the odds of healthcare practices consistently offering HPV vaccination were 44% lower (AOR: 0.56, 95% CI: 0.35-0.91, p-value: 0.019) in solo practices but 266% higher (AOR: 3.66, 95% CI: 2.04-6.58, p-value: < .001) in FQHC/public facilities. The common reasons healthcare practices do not consistently offer HPV vaccination were; HPV vaccination is not within the scope of the practice (48.1%), referrals to other clinics (27.7%), and limited personnel (11.4%). Non-physicians were more likely to report that HPV vaccination was not in their scope and to refer patients than physicians. Moreover, solo practices were more likely to report challenges with acquisition and storage of the vaccine and referral of patients as reasons for not consistently offering HPV vaccination than university/teaching hospitals, FQHC/public facilities, or group practices. System-level interventions including training of non-physicians and expansion of practice enrollment in programs that support HPV vaccine acquisition and storage are needed.
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Infecções por Papillomavirus , Vacinas contra Papillomavirus , Humanos , Estudos Transversais , Infecções por Papillomavirus/prevenção & controle , Padrões de Prática Médica , Vacinação , Conhecimentos, Atitudes e Prática em SaúdeRESUMO
OBJECTIVE: This study sought to evaluate the utility of the Global Health Security (GHS) index in predicting the launch of COVID-19 vaccine rollout by Organization for Economic Cooperation and Development (OECD) member countries. METHODS: Country-level data on the preparedness to respond to infectious disease threats through vaccination rollout were collected using the GHS index. OECD member countries were rank-ordered based on the percentage of their populations fully vaccinated against COVID-19. Rank-ordering was conducted from the lowest to the highest, with each country assigned a score ranging from 1 to 33. Spearman's rank correlation between the GHS index and the percentage of the population that is fully vaccinated was also performed. RESULTS: Israel, ranked 34th in the world on the GHS index for pandemic preparedness, had the highest percentage of the population that was fully vaccinated against COVID-19 within 2 months of the global vaccine rollout. The Spearman rank correlation coefficient between GHS index and the percentage of population fully vaccinated was -0.1378, with a p-value of 0.43. CONCLUSION: The findings suggest an absence of correlation between the GHS index rating and the COVID-19 vaccine rollout of OECD countries, indicating that the preparedness of OECD countries for infectious disease threats may not be accurately reflected by the GHS index.
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COVID-19 , Organização para a Cooperação e Desenvolvimento Econômico , Vacinas contra COVID-19 , Saúde Global , Humanos , SARS-CoV-2RESUMO
BACKGROUND: There is an urgent need for novel therapeutic strategies for reversing COVID-19-related lung inflammation. Recent evidence has demonstrated that the cholesterol-lowering agents, statins, are associated with reduced mortality in patients with various respiratory infections. We sought to investigate the relationship between statin use and COVID-19 disease severity in hospitalized patients. METHODS: A retrospective analysis of COVID-19 patients admitted to the Johns Hopkins Medical Institutions between March 1, 2020 and June 30, 2020 was performed. The outcomes of interest were mortality and severe COVID-19 infection, as defined by prolonged hospital stay (≥ 7 days) and/ or invasive mechanical ventilation. Logistic regression, Cox proportional hazards regression and propensity score matching were used to obtain both univariable and multivariable associations between covariates and outcomes in addition to the average treatment effect of statin use. RESULTS: Of the 4,447 patients who met our inclusion criteria, 594 (13.4%) patients were exposed to statins on admission, of which 340 (57.2%) were male. The mean age was higher in statin users compared to non-users [64.9 ± 13.4 vs. 45.5 ± 16.6 years, p <0.001]. The average treatment effect of statin use on COVID-19-related mortality was RR = 1.00 (95% CI: 0.99-1.01, p = 0.928), while its effect on severe COVID-19 infection was RR = 1.18 (95% CI: 1.11-1.27, p <0.001). CONCLUSION: Statin use was not associated with altered mortality, but with an 18% increased risk of severe COVID-19 infection.
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Tratamento Farmacológico da COVID-19 , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
The ongoing COVID-19 pandemic has devastated many countries with ripple effects felt in various sectors of the global economy. In November 2019, the Global Health Security (GHS) Index was released as the first detailed assessment and benchmarking of 195 countries to prevent, detect, and respond to infectious disease threats. This paper presents the first comparison of Organization for Economic Cooperation and Development OECD countries' performance during the pandemic, with the pre-COVID-19 pandemic preparedness as determined by the GHS Index. Using a rank-based analysis, four indices were compared between select countries, including total cases, total deaths, recovery rate, and total tests performed, all standardized for comparison. Our findings suggest a discrepancy between the GHS index rating and the actual performance of countries during this pandemic, with an overestimation of the preparedness of some countries scoring highly on the GHS index and underestimation of the preparedness of other countries with relatively lower scores on the GHS index.
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Betacoronavirus , Infecções por Coronavirus/epidemiologia , Atenção à Saúde , Saúde Global , Organização para a Cooperação e Desenvolvimento Econômico , Pneumonia Viral/epidemiologia , COVID-19 , Infecções por Coronavirus/mortalidade , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/virologia , Pessoal de Saúde , Humanos , Pandemias/prevenção & controle , Pneumonia Viral/mortalidade , Pneumonia Viral/prevenção & controle , Pneumonia Viral/virologia , Quarentena/economia , SARS-CoV-2RESUMO
The ongoing COVID-19 pandemic has devastated many countries with ripple effects felt in various sectors of the global economy. In November 2019, the Global Health Security (GHS) Index was released as the first detailed assessment and benchmarking of 195 countries to prevent, detect, and respond to infectious disease threats. This paper presents the first comparison of Organization for Economic Cooperation and Development OECD countries performance during the pandemic, with the pre-COVID-19 pandemic preparedness as determined by the GHS Index. Using a rank-based analysis, four indices were compared between select countries, including total cases, total deaths, recovery rate, and total tests performed, all standardized for comparison. Our findings suggest a discrepancy between the GHS index rating and the actual performance of countries during this pandemic, with an overestimation of the preparedness of some countries scoring highly on the GHS index and underestimation of the preparedness of other countries with relatively lower scores on the GHS index.
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BACKGROUND: The Echelon circular™ powered stapler (ECP stapler) obviates the need for manual firing of conventional circular staplers during the construction of a colorectal anastomosis, but has not been evaluated clinically. The aim of this study was to perform a clinical evaluation of this stapler. METHODS: A retrospective review of the initial clinical experience of a single surgeon using the ECP stapler for left-sided colorectal anastomosis construction during elective colorectal resections for benign and malignant disease was conducted by analyzing results from a prospectively maintained study database. Additionally, four attending colorectal and/or general surgeons who had performed ≥ 5 colorectal operations with the ECP stapler were invited to complete an anonymous online survey to subjectively assess the user experience with the device. Statistical analysis was conducted using Microsoft Excel Version 15.33. RESULTS: Seventeen patients underwent left-sided anastomotic reconstruction using the ECP stapler. All donuts (proximal and distal) were intact. Anastomotic integrity was evaluated using the air-leak test utilizing flexible video sigmoidoscopy. No leaks were observed, although one patient (5.9%) developed a postoperative pelvic abscess. The anonymous survey was completed by all four surgeons. Subjective evaluation of the ECP stapler suggests that the overall stapling quality, overall device ease-of-use, and the overall perception of anastomotic quality as above average when compared to manual 'end-to-end anastomosis' (EEA) stapling devices. CONCLUSIONS: In an initial clinical evaluation of the ECP stapler, the safety and ease-of-use of the device appears to be satisfactory. Powered stapling and the design of '3D stapling' may provide advantages over manual systems, and may improve the construction quality of left-sided colorectal anastomosis.
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Neoplasias Colorretais , Grampeamento Cirúrgico , Anastomose Cirúrgica , Neoplasias Colorretais/cirurgia , Humanos , Reto/cirurgia , Estudos Retrospectivos , Grampeadores CirúrgicosRESUMO
The aim of this study was to survey an international group of temporomandibular joint surgeons regarding their outcomes with alloplastic total joint replacement in skeletally immature patients and to review the literature linked to autogenous reconstruction and alloplastic replacement of the temporomandibular joint (TMJR) in this population. A total of 24 custom/patient-specific TMJ Concepts devices were implanted into 14 patients (eight male and six female). Their mean age was 14 years (range 7-17 years). Nine (64.3%) had bilateral devices and five (35.7%) had unilateral devices. The most prevalent diagnosis was idiopathic condylar resorption (33.3%), followed by ankylosis (16.7%). Concurrent orthognathic surgery was performed in four patients (28.6%). The TMJR was completed as a one-stage procedure in 11 patients (78.6%) and in two stages in three patients (21.4%). All surgeons reported improvements in maximum incisal opening with good function. The respondents reported no asymmetric mandibular growth or retrognathia after either bilateral or unilateral TMJR implantation. This pilot study indicates that the use of TMJR in the growing patient may be a useful modality in select cases. The encouraging results of experienced surgeons demonstrate and support the need for further studies on the utilization of TMJR in this patient population.
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Prótese Articular , Transtornos da Articulação Temporomandibular , Anquilose Dental , Adolescente , Criança , Feminino , Humanos , Masculino , Projetos Piloto , Inquéritos e Questionários , Articulação TemporomandibularRESUMO
BACKGROUND: Chinese aphrodisiacs have become popular remedy for sexual dysfunction and improvement of libido in men in Malawi. However, selling of these drugs seems not to be well regulated. Probably the aphrodisiacs that are currently on the market have unknown efficacy, potency and safety profiles. The aim of this study was to assess the efficacy of imported Chinese aphrodisiacs using guinea pigs as a model. MATERIALS AND METHODS: Two types of drugs were purchased from vendors in Blantyre City. Tonic tea, which was purported to improve erectile function and libido, and sperm multiplier tablets which were claimed to increase the sperm count. The tonic tea was prepared by soaking one tea bag in 100ml boiling water. The tea was cooled and administered to eight male experimental animals in varying doses. Each animal was introduced into a separate cage with a female guinea pig. Sexual behaviour such as mounting, sniffing behind the female were observed and recorded. Each sperm multiplier tablet was dissolved in distilled water and administered to the experimental animals in the morning and evening for seven days. At the end of the treatment, the experimental and control animals were sacrificed, their semen collected and analysed sperm motility, concentration and morphology. RESULTS: For the tonic tea, there were no statistical differences between the experimental and the control animals in terms of the number of mountings and sniffing behind the female. The sperm multiplier drug showed statistically significant differences between the experimental and the control animals in terms of the sperm motility (78.24 ± 1.35 vs. 86.54 ± 1.88, p< 0.05), and concentration (54.28 ± 1.24 vs. 67.59 ± 2.12, p<0.05). CONCLUSION: The tonic tea did not show any efficacy in improving erection and libido. The sperm multiplier tablets, purported to increase sperm production, significantly increased the sperm motility, sperm concentration in the treated animals.
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Afrodisíacos/farmacologia , Fertilidade/efeitos dos fármacos , Ereção Peniana/efeitos dos fármacos , Contagem de Espermatozoides , Motilidade dos Espermatozoides/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Animais , Afrodisíacos/administração & dosagem , Feminino , Cobaias , Libido/efeitos dos fármacos , Malaui , Masculino , Sêmen/efeitos dos fármacos , Comportamento SexualRESUMO
Previous studies have sought to associate the Pro12Ala variant of the peroxisome proliferator-activated receptor gamma2 (PPARG2) gene with type 2 diabetes, insulin resistance, and obesity, with controversial results. We have determined the Pro12Ala variant frequency in 370 nondiabetic Mexican Mestizo subjects and in five Mexican Amerindian groups and have investigated its possible association with lipid metabolism, insulin serum levels, and obesity in three of these populations. Two independent case-control studies were conducted in 239 nondiabetic individuals: 135 case subjects (BMI > or = 25 kg/m2) and 104 control subjects (BMI < 25 kg/m2). The PPARG2 Ala12 allele frequency was higher in most Amerindian populations (0.17 in Yaquis, 0.16 in Mazahuas, 0.16 in Mayans, and 0.20 in Triquis) than in Asians, African Americans, and Caucasians. The Pro12Ala and Ala12Ala (X12Ala) genotypes were significantly associated with greater BMI in Mexican Mestizos and in two Amerindian groups. X12Ala individuals had a higher risk of overweight or obesity than noncarriers in Mestizos (OR = 3.67; 95% CI, 1.42-9.48; p = 0.007) and in Yaquis plus Mazahuas (OR = 3.21; 95% CI, 1.27-8.11; p = 0.013). Our results provide further support of the association between the PPARG2 Ala12 allele and risk of overweight or obesity in Mestizos and two Amerindian populations from Mexico.
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Variação Genética/genética , Genética Populacional/métodos , Genótipo , Indígenas Norte-Americanos/genética , PPAR gama/genética , Adulto , Índice de Massa Corporal , Humanos , México , Pessoa de Meia-Idade , Obesidade/genéticaRESUMO
From June 1999 to September 2001, 216 bursal samples from broiler farms in the United States and from countries of Latin America were submitted to the Poultry Diagnostic and Research Center at the University of Georgia for the purpose of genotyping field infectious bursal disease viruses (IBDVs). The reverse transcriptase-polymerase chain reaction (RT-PCR) was used to amplify a 248-bp product, encompassing the hypervariable region of VP2 gene. The genotyping was conducted by restriction fragment length polymorphism (RFLP) analysis with six restriction endonucleases, DraI, SacI, TaqI, Sty, BstNI, and SspI. For the 150 samples received from the United States, 125 samples (83.3%) were RT-PCR positive for the presence of IBDV. One hundred positive samples (80%) had RFLP identical to the variant Delaware E strain, whereas 10 samples (8.0%) exhibited a RFLP pattern similar to this antigenic variant. Other IBDV strains such as Grayson Laboratory strain (GLS), Lukert, PBG-98, Delaware A, and the vaccine strains Sal-1 and D-78 were also detected. Two samples exhibited a pattern similar to the standard challenge (STC) strain, and seven strains (5.6%) were not classified by RFLP. Sixty-six bursal samples previously inactivated with phenol were received from Latin American countries. IBDV strains with analyzed genotypes similar to the Lukert strain were predominantly detected in Mexico. IBDV strains similar to variant E were detected in Colombia and Ecuador. Peru and Venezuela exhibited a higher heterogeneity of IBDV strains due to the detection of classic Delaware type as well as GLS variant strains. IBDV strains detected from Brazil and Dominican Republic exhibited RFLP patterns identical to very virulent IBDV strains prevalent in several countries in Europe, Asia, and Africa.
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Infecções por Birnaviridae/veterinária , Infecções por Birnaviridae/virologia , Galinhas/virologia , Vírus da Doença Infecciosa da Bursa/genética , Vírus da Doença Infecciosa da Bursa/isolamento & purificação , Filogenia , Doenças das Aves Domésticas/virologia , Animais , Infecções por Birnaviridae/epidemiologia , Genótipo , Vírus da Doença Infecciosa da Bursa/classificação , América Latina/epidemiologia , Polimorfismo de Fragmento de Restrição , Doenças das Aves Domésticas/epidemiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estados Unidos/epidemiologiaRESUMO
Nine Spanish isolates of infectious bursal disease virus (IBDV) were characterized and classified after reverse transcriptase-polymerase chain reaction of a 248-bp fragment of the VP2 gene hypervariable region and restriction fragment length polymorphism (RFLP). The restriction endonucleases (REs) used were BstNI, Sad, SspI, TaqI, DraI, and StyI. Sequencing of the amplified product and further comparison of these sequences with published sequence data from other IBDV strains were also performed. Very virulent and classic strains were identified. None of the strains identified had molecular characteristics similar to that of the American variant strains. Four very virulent strains (VG-248, 5939, 6145, and 7333) were digested by the TaqI, SspI, and StyI enzymes. The sequences of these strains were closely related to other European and Japanese very virulent IBDV (vvIBDV) strains. Strains VG-311, VG-262, and VG-208 were digested by the BstNI and Sad REs and were classified as classic strains. Strains VG-276 and VG-313 had unique RFLP patterns. VG-276 exhibited the SspI RE site, which has been reported as a characteristic of vvIBDV strains, whereas the VG-313 strain exhibited a Sad and StyI RE site indicative of the classic IBDV Edgar and 52-70 strains. However, nucleotide sequence analysis of the amplified hypervariable region strain VG-276 revealed a higher identity with the classic strains STC, 52/70, and 9109 IBDV strains, whereas strain VG-313 exhibited a higher identity with the vvIBDV strains.
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Infecções por Birnaviridae/veterinária , Vírus da Doença Infecciosa da Bursa/genética , Animais , Sequência de Bases , Embrião de Galinha , Galinhas , Genes Virais , Vírus da Doença Infecciosa da Bursa/classificação , Vírus da Doença Infecciosa da Bursa/isolamento & purificação , Vírus da Doença Infecciosa da Bursa/patogenicidade , Filogenia , Doenças das Aves Domésticas/virologia , RNA Viral/isolamento & purificação , Mapeamento por Restrição , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Espanha , VirulênciaRESUMO
Specific-pathogen-free sentinel birds were used as an initial biological system to isolate infectious bursal disease virus (IBDV) field isolates from commercial broiler farms exhibiting recurrent respiratory problems and poor performance. Reverse transcription (RT)-polymerase chain reaction (PCR) was used to amplify a 248-bp product encompassing the hypervariable region of the IBDV VP2 gene. Restriction fragment length polymorphism (RFLP) analysis of the RT-PCR products was performed with the restriction endonucleases DraI, SadI, TaqI, StyI, BstNI, and SspI. Two isolates (619 and 850) exhibited a RFLP pattern characteristic of Delaware variant E IBDV. Restriction enzyme digestion for four isolates (625, 849, 853, and 11,153) revealed unmatched RFLP patterns when compared with reference IBDV strains. Nucleotide and deduced amino acid sequence analyses of the VP2 hypervariable region for these six isolates revealed identity (96.3% up to 98%) with Delaware E variant IBDV strain. However, serine at position 254, which is characteristic of Delaware variant strains, was substituted by asparagine in these six isolates. The seventh IBDV isolate (9109) also exhibited a unique RFLP pattern, which included the SspI restriction site, which is characteristic of very virulent (vv) IBDV strains. Nucleotide and amino acid sequence analyses of the hypervariable region for this isolate revealed identity (90%) with the standard challenge strain. However, the leucine residue at position 294 was substituted by isoleucine. This substitution corresponds to one of the amino acids that are conserved in the vvIBDV strains. Antigenic index studies of the predicted amino acid sequence of the hypervariable region of VP2 from isolates 619, 625, 849, 850, 853, and 11,153 exhibited a profile almost identical to variant E, whereas the isolate 9109 exhibited a profile characteristic of standard IBDV strains.
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Infecções por Birnaviridae/veterinária , Vírus da Doença Infecciosa da Bursa/genética , Doenças das Aves Domésticas/virologia , Proteínas Estruturais Virais/genética , Sequência de Aminoácidos , Animais , Antígenos Virais/análise , Antígenos Virais/química , Sequência de Bases , Infecções por Birnaviridae/virologia , Galinhas , Vírus da Doença Infecciosa da Bursa/classificação , Vírus da Doença Infecciosa da Bursa/isolamento & purificação , Dados de Sequência Molecular , Filogenia , Polimorfismo de Fragmento de Restrição , RNA Viral/análise , RNA Viral/química , RNA Viral/isolamento & purificação , Mapeamento por Restrição/veterinária , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Homologia de Sequência de Aminoácidos , Organismos Livres de Patógenos Específicos , Proteínas Estruturais Virais/químicaRESUMO
1. Kinetic and physico-chemical studies on human placental microsomal fraction confirmed that the ATPase and ADPase activities detected in this fraction correspond to the enzyme ATP-diphosphohydrolase or apyrase (EC 3.6.1.5). These include substrate specificity, and coincident M(r) and pI values of both ATPase-ADPase activities. 2. This enzyme hydrolyses both the free unprotonated and cation-nucleotide complex, the catalytic efficiency for the latter being considerably higher. 3. Microsomal apyrase is insensitive to ouabain and Ap5A. The highly purified enzyme was only inhibited by o-vanadate, DES and slightly by DCCD. 4. Apyrase seems to be a glycoprotein from its interaction with Concanavalin-A. 5. Preliminary studies on the essential amino acid residues suggest the participation of Arg, Lys and His residues, and discard the requirement of -SH, COO-, -OH, and probably also Tyr and Trp. 6. Two kinetic modulatory proteins of apyrase were detected in placental tissue. An activating protein was found in the soluble fraction and an inhibitory protein was loosely bound to the membranes. 7. The proposed in vivo function for apyrase is related to the inhibition of platelet aggregation due to its ADPase activity, which is supported by the direct effect on washed platelets and by its plasma membrane localization.