[Progress in research of economic evaluation of non-pharmaceutical interventions for COVID-19 prevention and control].

Objective: To understand the research progresses of economic evaluation of non-pharmaceutical interventions (NPIs) both at home and abroad, and provide reference for economic evaluation of NPIs using real-world data in China. Methods: The literature retrieval was conducted by searching Chinese and English databases to indude papers about economic evaluation of NPIs and integrated NPIs published from January, 2020 to December, 2021, and the results were analyzed comprehensively. Results: A total of 30 Chinese and English literatures about economic evaluation of NPIs for COVID-19 prevention and control were included; including 7 papers about nucleic acid and testing and screening, 6 papers about individual prevention and protection measures, 12 papers about integrated implementation of individual prevention and protection, social distancing, nucleic acid or antigen testing, community screening and symptom screening, as well as close contact tracing and isolation/quarantine, and 5 papers about contain strategies, such as lockdown. This study found that personal protection, social distancing, and testing-tracing-isolation measures were cost-effective; however, different combinations of NPIs might lead to different results. Moreover, the cost of lockdown was high, which might cause huge economic burden. Conclusions: Most NPIs are cost-effective except lockdown, while the cost-effectiveness of the integrations of NPIs at different levels and in different scenarios needs to be further evaluated. It is necessary to carry out economic evaluation of integrated NPIs and the combination of NPIs with other interventions, such as vaccination and medication, based on real-world settings in China.

[Progress in research of economic evaluation of COVID-19 vaccination strategies].

Objective: To understand the research progresses of economic evaluation of COVID-19 vaccination strategies both at home and abroad, and provide reference for the economic evaluation of COVID-19 vaccination strategies using real word data in China. Methods: Literature retrieval was conducted for related papers published from January, 2020 to December, 2021 in Chinese and English databases, including the economic evaluation of COVID-19 vaccination, and the results of the related literatures were narratively integrated. Results: A total of 16 English literatures (including 3 reviews) were included, and it was found that the COVID-19 vaccination was cost-effective or cost-saving regardless of the vaccine types, while the cost-effectiveness in different population and under different vaccination dose strategies varied due to vaccine efficacy, vaccine price, duration of natural immunity, duration of vaccination campaign, vaccine supply, and vaccination pace. Conclusions: China lacks suitable evidences of economic evaluation of COVID-19 vaccination strategies based on real-world data in the context of long-term epidemic. Therefore, further researches of suitable strategies of booster COVID-19 vaccination are needed.

[Study on the health literacy and related factors of the cancer prevention consciousness among urban residents in China from 2015 to 2017].

Objective: To understand the health literacy and relevant factors of cancer prevention consciousness in Chinese urban residents from 2015 to 2017. Methods: A cross-sectional survey was conducted in 16 provinces covered by the Cancer Screening Program in Urban China from 2015 to 2017. A total of 32 257 local residents aged ≥18 years old who could understand the investigation procedure were included in the study by using the cluster sampling method and convenient sampling method. All local residents were categorized into four groups, which contained 15 524 community residents, 8 016 cancer risk assessment/screening population, 2 289 cancer patients and 6 428 occupational population, respectively. The self-designed questionnaire was used to collect the information of demographic characteristics and cancer prevention consciousness focusing on nine common risk factors, including smoking, alcohol, fiber food, food in hot temperature or pickled food, chewing betel nut, helicobacter pylori, moldy food, hepatitis B infection, estrogen, and exercise. The logistic regression model was adopted to identify the influencing factors. Results: The overall health literacy of the cancer prevention consciousness was 77.4% (24 980 participants), with 77.4% (12 018 participants), 79.9% (6 406 participants), 77.2% (1 766 participants) and 74.5% (4 709 participants) in each group (P<0.001). The correct response rates for nine risk factors ranged from 55.2% to 93.0%. The multivariate logistic regression analysis showed that compared with community residents, people with primary school level education or below, and the number of people living together in the family <3, the cancer risk assessment/screening intervention population, cancer patients, those with junior high school level educationor above and the number of people living in the family ≥3 had better health literacy of the cancer prevention consciousness (all P values <0.05). Compared with females, 39 years old and below, government-affiliated institutions or civil servants, from the eastern region, males, older than 40 years, company or enterprise employees, and from the middle or western region had worse health literacy of the cancer prevention consciousness (all P values <0.05). Conclusion: The health literacy of the cancer prevention consciousness in Chinese urban residents should be improved. The cancer screening intervention, gender, age, education, occupation, the number of people co-living in the family, and residential region were associated with the health literacy of the cancer prevention consciousness.

[Analysis on the consciousness of the cancer early detection and its influencing factors among urban residents in China from 2015 to 2017].

Objective: To understand the consciousness of the cancer early detection among urban residents and identify the influencing factors from 2015 to 2017. Methods: A cross-sectional survey was conducted in 16 provinces covered by the Cancer Screening Program in Urban China from 2015 to 2017. A total of 32 257 local residents aged ≥18 years old who could understand the investigation procedure were included in the study by using the cluster sampling method and convenient sampling method. All local residents were categorized into four groups, which contained 15 524 community residents, 8 016 cancer risk assessment/screening population, 2 289 cancer patients and 6 428 occupational population, respectively. Self-designed questionnaires were used to collect population, socioeconomic indicators, self-cancer risk assessment, regular participation in physical examination and other information. The multivariate logistic regression model was used to identify the factors of people who had not regularly participated in the regular physical examination in the past five years. Results: The self-assessment results of 32 357 residents showed that there were 27.54% (8 882) of total study population with self-reported cancer risk, 45.48% (14 671) without cancer risk and 26.98% (8 704) with unclear judgement on their own cancer risk. Among population with cancer risk, 79.84% (7 091) considered physical examination accounted. In the past five years, there were 21 105 (65.43%) residents participated in regular physical examination and 11 148 (34.56%) participated in non-scheduled one, respectively. The multivariate logistic regression analysis showed that compared with unmarried and western region residents, divorced, middle and eastern region residents had a stronger consciousness to participate in the regular physical examination (P<0.05). Compare with residents with annual household income less than 20 000 CNY in 2014, cancer risk assessment/screening intervention population, and self-assessment with cancer risk, residents with annual household income between 20 000 CNY and 59 000 CNY in 2014, occupational population, community residents, cancer patients, self-reported cancer-free risk, and self-assessment with unclear judgement of cancer risk were less likely to participate in the regular physical examination (all P values <0.05). Conclusion: From 2015 to 2017, the Chinese urban residents had a acceptable consciousness of the cancer early detection. The marital status, annual household income, population group and self-assessment of cancer risk were related to the consciousness of the cancer early detection of people who had not participated in the regular physical examination in the past five years.

[Analysis on the consciousness of the early cancer diagnosis and its related factors among urban residents in China from 2015 to 2017].

Objective: To understand the consciousness of the cancer early diagnosis among urban residents and identify the related factors from 2015 to 2017. Methods: A cross-sectional survey was conducted in 16 provinces covered by the Cancer Screening Program in Urban China from 2015 to 2017. A total of 32 257 local residents aged ≥18 years old who could understand the investigation procedure were included in the study by using the cluster sampling method and convenient sampling method. All local residents were categorized into four groups, which contained 15 524 community residents, 8 016 cancer risk assessment/screening population, 2 289 cancer patients and 6 428 occupational population, respectively. The general demographic characteristics, the consciousness of the cancer early diagnosis (whether people would have a willingness or encourage their relatives/friends to confirm the abnormal results once which were detected from the physical examination) and other information were collected by using the self-designed questionnaire. The non-conditional logistic regression model was used to identify the relateol factors related to the consciousness of the cancer early diagnosis. Results: As for residents with abnormal result from the physical examination, 89.29% (28 802) of residents would choose to seek medical treatment for further diagnosis. If their relatives/friends had abnormal results from the physical examination, 89.55% (28 886) of residents would encourage their relatives/friends to confirm the diagnosis in time. The non-conditional logistic regression model analysis showed that compared with the public institution staff/civil servants, annual household income less than 20 000 CNY, the western region and the cancer risk assessment/screening intervention population, the company staff, annual household income about 40 000 CNY and more, and the residents from the middle and eastern region had a stronger consciousness to seek further diagnosis; while the unemployed residents and community residents were less likely to seek further diagnosis (P<0.05). Conclusions: From 2015 to 2017, the Chinese urban residents had a good consciousness of the cancer early diagnosis. Occupation, annual household income, residential region and population group were related to the consciousness of the cancer early diagnosis.

[Analysis on the consciousness of the early cancer treatment and its influencing factors among urban residents in China from 2015 to 2017].

Objective: To understand the consciousness of the cancer early treatment and its demographic and socioeconomic factors. Methods: A cross-sectional survey was conducted in 16 provinces covered by the Cancer Screening Program in Urban China (CanSPUC) from 2015 to 2017. A total of 32 257 local residents aged ≥18 years old who could understand the investigation procedure were included in the study by using the cluster sampling method and convenient sampling method. All local residents were categorized into four groups, which contained 15 524 community residents, 8 016 cancer risk assessment/screening population, 2 289 cancer patients and 6 428 occupational population, respectively. The questionnaire collected personal information, the consciousness of the cancer early treatment and relevant factors. The Chi square test was used to compare the difference between the consciousness of the cancer early treatment and relevant factors among the four groups. The logistic regression model was used to analyze the influencing factors related to the consciousness of the cancer early treatment. Results: With the assumption of being diagnosed as precancer or cancer, 89.97% of community residents, 91.84% of cancer risk assessment/screening population, 93.00% of cancer patients and 91.52% of occupational population would accept active treatments (P<0.001). If the immediate family members were diagnosed as precancer or cancer, people who would encourage their family members to receive early treatment in the four groups accounted for 91.96%, 91.94%, 92.44% and 91.55%, respectively (P<0.001). The company employees, annual household income with 40 000 yuan and more and other three groups had a relatively better consciousness of the cancer early treatment (P<0.05). Male, widowed, unemployed and from the central and western regions had a relatively worse consciousness of the cancer early treatment (P<0.05). Conclusion: Residents in urban China participants had a good consciousness of the cancer early treatment. The marital status, occupation, annual household income and residential regions were major factors related to the consciousness of the cancer early treatment.

[Analysis on the health literacy of the cancer prevention and treatment and its related factors among urban residents in China from 2015 to 2017].

Objective: To understand the health literacy of the cancer prevention and treatment among urban residents of China, and explore the related factors. Methods: A cross-sectional survey was conducted in 16 provinces covered by the Cancer Screening Program in Urban China (CanSPUC) from 2015 to 2017. A total of 32 257 local residents aged ≥18 years old who could understand the investigation procedure were included in the study by using the cluster sampling method and convenient sampling method. All local residents were categorized into four groups, which contained 15 524 community residents, 8 016 cancer risk assessment/screening population, 2 289 cancer patients and 6 428 occupational population, respectively. The health literacy of the cancer prevention, early discovery, early diagnosis, early treatment and the demands of cancer prevention and treatment knowledge was analyzed. The level of health literacy among different groups were calculated and compared. The binary logistic regression model was used to analyze the influencing factors of the health literacy of the cancer prevention and treatment. Results: The level of health literacy of the cancer prevention and treatment was 56.97% among all study population; in each group it was 55.01% for community residents, 59.08% for cancer risk assessment/screening population, 61.99% for cancer patients and 57.31% for occupational population, respectively (P<0.001). The level of health literacy of the cancer prevention and treatment of residents aged 50 to 69 years old, other occupational groups, unmarried, the central and western region residents and the group with unclear self-assessment of cancer risk was significantly lower than that of residents younger than 40 years old, personnel of public institutions/civil servants, married, the eastern region residents and the group whose self-assessment without cancer risk (P<0.05) . The level of health literacy of cancer prevention and treatment of females, people who went to high school or over, cancer risk assessment/screening population, cancer patients and occupational population was significantly higher than that of males, people who had an education level of primary school or below and community residents (P<0.05) . Conclusion: The health literacy of the cancer prevention and treatment of urban residents in China was relatively high, but there was still room for improvement. Gender, age, educational level, occupation, region, marital status, self-assessment of cancer risk, and type of respondents were the key influencing factors of the health literacy of the cancer prevention and treatment. Male, 50-69 years old, lower educational level, central and western regions, unclear cancer risk self-assessment, and without specific environmental exposure to cancer prevention and treatment knowledge or related risk factors were the characteristics of the key intervention group of the health literacy of the cancer prevention and treatment.

[Analysis on the demand, access and related factors of cancer prevention and treatment knowledge among urban residents in China from 2015 to 2017].

Objective: To investigate the demand and access to the cancer prevention and treatment knowledge and related factors among urban residents in China from 2015 to 2017. Methods: A cross-sectional survey was conducted in 16 provinces covered by the Cancer Screening Program in Urban China from 2015 to 2017. A total of 32 257 local residents aged ≥18 years old who could understand the investigation procedure were included in the study by using the cluster sampling method and convenient sampling method. All local residents were categorized into four groups, which contained 15 524 community residents, 8 016 cancer risk assessment/screening population, 2 289 cancer patients and 6 428 occupational population, respectively. The self-designed questionnaire was used to collect the information of general demographic characteristics, the demand and access to cancer prevention and treatment knowledge, and the influencing factors of the attitude. The Chi-square test was used to analyze the difference of the demand of the cancer prevention knowledge among different groups and the corresponding factors of the cancer prevention and treatment knowledge were analyzed by using the logistic regression model. Results: The proportion of residents who need the cancer prevention and treatment knowledge was 79.5%. The demand rate of the inducement, symptom and diagnosis methods of cancer in the occupational population was highest, about 66.8%, 71.0% and 20.8%, respectively. The demand rate of treatment methods and cost in current cancer patients was the highest, about the 45.9% and 21.9%, respectively. The top three sources to acquire the cancer prevention and treatment knowledge were "broadcast or television" (69.5%), "books, newspapers, posters or brochures" (44.7%) and "family and friends" (33.8%). The multivariate analysis showed that compared with public institution personnel/civil servants, unmarried/cohabiting/divorced/widowed and others, annual household income less than 20 000 CNY, from the eastern region, people without cancer diagnosis and people with self-assessment of cancer risk, the demand rate of cancer prevention and treatment knowledge was higher in enterprise personnel/workers, married, annual household income between 60 000 CNY and 150 000 CNY, from the central region, people with cancer and people with unclear cancer risk (all P values <0.05). Conclusion: There was a high demand for the cancer prevention and treatment knowledge among urban residents in China from 2015 to 2017. The main access to the knowledge is from the radio or television. The occupation, marital status, annual household income, residential region, health status and risk of disease were the main factors of the demand of the cancer prevention and treatment knowledge.

Streptococcus agalactiae infection in domestic rabbits, Oryctolagus cuniculus.

Streptococcus agalactiae (Group B streptococcus, GBS) has emerged as an important pathogen that affects humans and animals, including aquatic species. In August 2011, a severe infectious disease affecting rabbits, which caused 42% mortality, occurred in Mianyang, Sichuan Province, China. The main clinical signs included acute respiratory distress syndrome, fever, paddling and convulsions. A Gram-positive, chain-forming coccus was isolated from the primary organs and tissues of diseased rabbits and then identified as S. agalactiae by morphology, biochemical and physiological characteristics, 16S rDNA and gyrB gene sequences analysis. All isolates of S. agalactiae showed a similar antibiotic susceptibility, which were sensitive to florfenicol, ampicillin,gentamicin and norfloxacin, as well as being resistant to penicillin, amoxicillin and tetracycline. To our knowledge, this is the first report on S. agalactiae natural infection in domestic rabbits.

Streptococcus agalactiae, an emerging pathogen for cultured ya-fish, Schizothorax prenanti, in China.

Streptococcus agalactiae (Group B streptococcus) has emerged as an important pathogen that affects humans and animals, including aquatic species. S. agalactiae infections are becoming an increasing problem in aquaculture and have been reported worldwide in a variety of fish species, especially those living in warm water. Recently, a very serious infectious disease of unknown aetiology broke out in ya-fish (Schizothorax prenanti) farms in Sichuan Province. A Gram-positive, chain-forming coccus was isolated from moribund cultured ya-fish. The goals of this study were to identify the bacterial strains isolated from diseased fish between 2009 and 2011 in Sichuan Province, China, to evaluate the pathogenicity of the pathogen in ya-fish, crucian carp (Carassius carassius) and the Nile tilapia (Oreochromis niloticus); and to determine the susceptibility of the pathogen strains to many currently available anti-microbial agents. The virulence tests were conducted by intraperitoneal injection of bacterial suspensions. In this study, four strains of a Gram-positive, chain-forming coccus were isolated from moribund cultured ya-fish (S. prenanti). The coccoid microorganism was identified as S. agalactiae using a commercial streptococcal grouping kit and 16S rDNA sequencing analysis. Susceptibility of the isolates to 22 antibiotics was tested using the disc diffusion method. All isolates showed a similar antibiotic susceptibility, which were sensitive to amoxicillin, ciprofloxacin, lomefloxacin, chloramphenicol, rifampin, vancomycin, azithromycin, florfenicol, cefalexin, cefradine and deoxycycline and resistant to gentamicin, sinomin (SMZ/TMP), penicillin, tenemycin, fradiomycin and streptomycin. Furthermore, the virulence tests were conducted by intraperitoneal injection of the isolated strain GY101 in ya-fish, crucian carp and the Nile tilapia. This coccus was lethal to ya-fish, Nile tilapia and crucian carp. The mortality rates of infected ya-fish were 100%, 100%, 60% and 20% at doses of 1.0 × 107, 1.0 × 106, 1.0 × 105 and 1.0 × 104 CFU/fish, respectively. The values were 100%, 80%, 60% and 30% for Nile tilapia and 100%, 60%, 10% and 0% for crucian carp. To our knowledge, this is the first report of S. agalactiae as a pathogen of ya-fish.

Novel regulators of vitamin D action and metabolism: Lessons learned at the Los Angeles zoo.

We undertook an investigation of an outbreak of rachitic bone disease in the Emperor Tamarin New World primate colony at the Los Angeles Zoo in the mid-1980s. The disease phenotype resembled that observed in humans with an inactivating mutation of the vitamin D receptor (VDR), hypocalcemia, high 1,25-dihydroxyvitamin D (1,25-(OH)(2)D) levels, and rickets in rapidly growing adolescent primates. In contrast to the human disease, the New World primate VDR was functionally normal in all respects. The proximate cause of vitamin D hormone resistance in New World primates was determined to be the constitutive overexpression of a heterogeneous nuclear ribonucleoprotein in the A family which we coined the vitamin D response element binding protein (VDRE-BP). VDRE-BP competed in trans with the VDR-retinoid X receptor (RXR) for binding to the vitamin D response element. VDRE-BP-legislated resistance to 1,25-(OH)(2)D was antagonized (i.e., compensated) by another set of constitutively overexpressed proteins, the hsp-70-related intracellular vitamin D binding proteins (IDBPs). IDBPs, present but expressed at much lower levels in Old World primates including man, exhibited a high capacity for 25-hydroxylated vitamin D metabolites and functioned to traffic vitamin Ds to specific intracellular destinations to promote their action and metabolism.

Autoregulation of 1,25-dihydroxyvitamin D synthesis in macrophage mitochondria by nitric oxide.

Tissue macrophages from patients with granuloma-forming disease, most notably sarcoidosis, express a 25-hydroxyvitamin D-1-hydroxylase which can produce in vivo sufficient quantities of the active vitamin D metabolite 1,25-dihydroxyvitamin D to cause hypercalcemia. In contrast to the NADPH-dependent cytochrome P450-linked mixed function oxidase which is normally only expressed in significant quantity in proximal renal tubular cells and regulated in an endocrine fashion, the mitochondrial-based 1-hydroxylase in the macrophage [1] is stimulated in a paracrine mode by cytokines (i.e., IFN-gamma) and lipopolysaccharide (LPS) [2] requires an extracellular source of L-arginine for full basal expression and [3] can be regulated in an intracrine fashion by nitric oxide (NO). In these experiments we employed inducible nitric oxide synthase (iNOS)-free, intact mitochondria preparations from the avain macrophage-like cell line HD-11, which constitutively express the 1-hydroxylase, and nonenzymatically-generated NO to investigate NO-mediated autoregulation of the macrophage 1-hydroxylase. Sodium nitroprusside (SNP)- or S-nitroso-N-acetyl-penicillamine (SNAP)-induced up-regulation of the 1-hydroxylase required the presence of either NADPH or NADP in the reaction mixture, while NO-induced inhibition of mitochondrial 1,25-(OH)2D3 synthesis was NO-dependent and NADP/NADPH-independent. These data suggest NO has bifunctional effects on the macrophage 1-hydroxylase. At relatively high concentrations NO competes with O2 for enzyme binding, inhibiting hormone synthesis. At lower production levels, NO serves as a source of reducing equivalents for the enzyme by providing for the reduction of NADP to NADPH.

Coordinate regulation of nitric oxide and 1,25-dihydroxyvitamin D production in the avian myelomonocytic cell line HD-11.

Cells of the monocyte/macrophage lineage are capable of both nitric oxide (NO) and 1,25-dihydroxyvitamin D [1, 25-(OH)2D] production through expression of inducible nitric oxide synthase (iNOS) and a putative 25-hydroxyvitamin D (25-OHD)-1-hydroxylase, respectively. We have recently reported that 1,25-(OH)2D synthesis in the chick myelomonocytic cell line HD-11 is restricted by inhibition of iNOS. In the current set of experiments, measuring nitrite, a stable water-soluble secreted metabolite of NO as an index of iNOS activity and 1,25-(OH)2D3 in lipid extracts of cells incubated with 200 nM 25-OHD3 as an index of 1-hydroxylase activity, we demonstrate that NO and 1,25-(OH)2D production by HD-11 cells are temporally related, induced by the same kinds of activating agents, and coordinately regulated. NO and 1,25-(OH)2D3 production by HD-11 cells was stimulated severalfold by the macrophage stimulators interferon-gamma and lipopolysaccharide and by an autologous, nonlipid, heat-labile factor with an apparent molecular mass approximately 10,000 daltons. As expected NO synthesis was 1) dependent upon the presence of L-arginine in the extracellular medium, 2) subject to significant stimulation by Nw-hydroxy-L-arginine, an L-arginine-derived intermediate in NO biosynthesis, and by sodium nitroprusside, a non-L-arginine-dependent source of intracellular NO, and 3) inhibited by Nw-nitro-L-arginine methyl ester, a competitive inhibitor of iNOS. At high NO production rates, induced either by high-dose lipopolysaccharide or by sodium nitroprusside exposure, there was an apparent downturn in 1,25-(OH)2D3 synthesis, suggesting functional dependence of the 1-hydroxylase on NO but ultimate inhibition of 1,25-(OH)2D3 synthetic capacity at high levels of intracellular NO production. On the basis of these results we postulate that the macrophage 25-OHD-1-hydroxylation reaction may be dependent on iNOS-generated NO as a soluble source of electrons and regulated in an autocrine mode by a macrophage-derived NO stimulatory factor and NO itself.

Regulated production and intracrine action of 1,25-dihydroxyvitamin D3 in the chick myelomonocytic cell line HD-11.

To better understand the extrarenal production of active vitamin D metabolites by cells of the monocyte/macrophage lineage, we investigated the 25-hydroxyvitamin D (25OHD)-1-hydroxylation reaction in the v-myc-transformed chick myelomonocytic cell line HD-11; the 1-hydroxylation reaction in this cell line has a high affinity for 25-hydroxylated vitamin D substrates, is localized to mitochondria, and is associated with cytochrome P450 activity. In this study we demonstrated that the HD-11 cell 1-hydroxylation reaction in vitro is not affected by the majority of extracellular regulatory factors that modulate expression of the renal 25OHD-1-hydroxylase in vivo. A 50% increase in extracellular calcium and phosphate concentrations, physiological inhibitory events for renal 1,25-dihydroxyvitamin D [1,25-(OH)2D] synthesis, did not decrease basal expression of the HD-11 cell 1-hydroxylation reaction, nor did a 50% decrease in extracellular calcium and phosphate concentrations, stimulatory signals for the 1-hydroxylase in vivo, increase 1,25-(OH)2D3 synthesis in vitro. Receptor-saturating concentrations of PTH and PTH-related peptide were similarly without effect. In contrast, the HD-11 1-hydroxylation reaction was significantly stimulated in a dose-dependent fashion by the macrophage stimulatory agents lipopolysaccharide [P < 0.001 at a maximum effective concentration (EC100) of 25 micrograms/ml] and interferon-gamma (P < 0.001 at EC100 of 1000 IU/ml) and by insulin-like growth factor-I (P < 0.01 at EC100 of 15 nM) with the rank order of stimulation being interferon-gamma > lipopolysaccharide > insulin-like growth factor-I. Dexamethasone (> or = 10 nM) and the cytochrome P450 inhibitors (EC100, 20 microM), ketoconazole, clotrimazole, and menadione, all significantly inhibited the HD-11 cell 1-hydroxylation reaction. The naphthoquinone menadione, which blocks electron transfer to the P450-associated enzyme, was the most effective inhibitor of the reaction in both intact cells (3 +/- 1% of basal expression; P < or = 0.002) and after reconstitution of HD-11 cell mitochondrial extracts with a ferredoxin, reductase, O2, and NADPH (5 +/- 1% of basal; P < or = 0.02). We have also shown that 1,25-(OH)2D3 produced from substrate 25OHD3 appears to exert an endogenous (intracrine) inhibitory effect on HD-11 cell growth; incubation of HD-11 cells with a concentration of ketoconazole (10 microM) known to reduce 1,25-(OH)2D3 production by roughly 50% restored 50% of the growth deficit induced by 1,25-(OH)2D3 (EC100, 100 nM).(ABSTRACT TRUNCATED AT 400 WORDS)

A role for nitric oxide in the regulated expression of the 25-hydroxy-vitamin D-1-hydroxylation reaction in the chick myelomonocytic cell line HD-11.

We have recently described the existence of a cytochrome P450-associated, mitochondrial-based 25-hydroxyvitamin D (25-OHD)-1-hydroxylation reaction in the chick macrophage-like cell line HD-11. Considering that this reaction is regulated by the same set of factors (ie. interferon-gamma, lipopolysaccharide, and glucocorticoids) that modulate expression of the macrophage nitric oxide synthase (mac NOS), we investigated the possibility that endogenous nitric oxide (NO) production may be linked to 1,25-dihydroxyvitamin D3 (1,25-(OH)2D) synthesis by HD-11 cells in vitro. To test this hypothesis we investigated the effects excluding from the extracellular medium the essential amino acid L-arginine, substrate for endogenous NO production, on the basal and stimulated expression of the HD-11 cell 25-OHD-1-hydroxylation reaction. Depletion of L-arginine from the extracellular medium for as little as 6 h resulted in a significant decrease (p < 0.02) in basal 1,25-(OH)2D synthesis; after 15 h in an L-arginine-free environment hormone production was reduced to < 10% of basal levels without any adverse affect on cell viability. Reintroduction of L-arginine, but not D-arginine, into the extracellular medium restored 1,25-(OH)2D3 synthetic capacity fully if done after < or = 6 h of incubation in the absence of L-arginine. Competitive inhibition of NOS with Nw-nitro-L-arginine methyl ester (p < 0.002) and Nw-nitro-L-arginine (p < 0.02) significantly inhibited 1,25-(OH)2D synthesis, indicating that macrophage NO generating capacity is functionally linked to endogenous synthesis of the active vitamin D metabolite.

Subcellular localization and partial purification of the 25-hydroxyvitamin D3 1-hydroxylation reaction in the chick myelomonocytic cell line HD-11.

Hypercalcemia in human granuloma-forming diseases like sarcoidosis results from the endogenous overproduction of 1,25-dihydroxyvitamin D [1,25-(OH)2D] by disease-activated tissue macrophages. The recent identification of an immortalized chick myelomonocytic cell line, HD-11, that constitutively expresses a 25-hydroxyvitamin D (25-OHD) 1-hydroxylation reaction has alleviated dependence on studying primary macrophage cultures with no replicative potential in vitro. In these experiments we established conditions for the maximal expression of the HD-11 cell 25-OHD3-1-hydroxylation reaction and localized this activity to the mitochondrial fraction. On a per cell basis, the activity of HD-11 cell 25-OHD3 1-hydroxylation reaction was comparable to that in primary cultures of chick renal tubular epithelial cells, which express the authentic renal 25-OHD3 1-hydroxylase. Maximal product yield was achieved after incubation of HD-11 cells with 200 nM 25-OHD3 for 3 h. Although adherent monolayers possessed 3- to 4-fold more capacity for hormone production than cells in suspension, suspended cells exhibited easily detectable 25-OHD3 catalytic activity (0.58 +/- 0.08 pmol per 10(6) cells per h; +/- SEM), 50% of which remained solubilized in a sonicate of suspended cells cleared of nuclei and plasma membrane. Subcellular localization disclosed 91% of the residual activity to be concentrated in the mitochondrial subfraction. A detergent-solubilized extract of this mitochondrial subfraction contained 1.9 +/- 0.3 pmol 1,25-(OH)2D3 synthetic capacity per mg protein. The catalytic activity (1-hydroxylase activity) was concentrated 20.2-fold after chromatography on octyl-amino agarose and was associated with 0.054 nmol cytochrome P450 per mg protein.(ABSTRACT TRUNCATED AT 250 WORDS)