[Epidemiological characteristics and outcome analysis of 266 patients with inhalation injuries combined with total burn area less than 30% total body surface area].

Objective: To explore the epidemiological characteristics and treatment outcomes of patients with inhalation injuries combined with total burn area less than 30% total body surface area (TBSA). Methods: A retrospective observational study was performed on medical records of 266 patients with inhalation injuries combined with total burn area less than 30%TBSA who were admitted to the First Affiliated Hospital of Naval Medical University from January 2008 to December 2016 and met the inclusion criteria. The following statistical data of the patients were collected, including gender, age, injury site, injurious factors of inhalation injury, degree of inhalation injury, combined total burn area, tracheotomy, time of tracheotomy, mechanical ventilation, whether stayed in intensive care unit (ICU) or not, microbial culture results of bronchoalveolar lavage fluid, length of hospital stay, length of ICU stay, mechanical ventilation days, and respiratory tract infections. Single factor and multivariate linear regression analysis were used to screen out the risk factors impacting the length of hospital stay, length of ICU stay, and mechanical ventilation days of patients. Single factor and multivariate logistic regression analysis were used to screen out the risk factors impacting respiratory tract infections of patients. Results: The 266 patients included 190 males and 76 females, with the majority age of above or equal to 21 years and below 65 years (217 patients). The major injury site was confined space. The major factor causing inhalation injury was hot air. Mild and moderate inhalation injuries were more common in patients. The combined total burn area was 9.00% (3.25%, 18.00%) TBSA. In 111 patients who had tracheotomy, most of them received the procedures before being admitted to the First Affiliated Hospital of Naval Medical University. The length of hospital stay of patients was 27 (10, 55) days. The length of ICU stay of 160 patients who were hospitalized in ICU was 15.5 (6.0, 40.0) days. The mechanical ventilation days of 109 patients who were conducted with mechanical ventilation were 6.0 (1.3, 11.5) days. A total of 119 patients were diagnosed with respiratory tract infections, with 548 strains including 35 types of pathogens isolated, mainly Gram-negative bacteria. Single factor linear regression analysis showed that age, injurious factors of inhalation injury, combined total burn area, degree of inhalation injury (moderate and severe), tracheotomy, mechanical ventilation, and respiratory tract infections were the factors impacting the length of hospital stay of patients (ß=-0.198, -0.224, 0.021, 0.127, 0.164, -0.298, 0.357, 0.447, 95% confidence interval (CI)=-0.397--0.001, -0.395--0.053, 0.015-0.028, 0.009-0.263, 0.008-0.319, -0.419--0.176, 0.242-0.471, 0.340-0.555, P<0.1). Multivariate linear regression analysis showed that with mechanical ventilation and respiratory tract infections were the independent risk factors impacting the length of hospital stay of patients (ß=0.146, 0.383, 95% CI=0.022-0.271, 0.261-0.506, P<0.05 or P<0.01). Single factor linear regression analysis showed that injurious factors of inhalation injury, combined total burn area, degree of inhalation injury (moderate and severe), tracheotomy (no tracheotomy and prophylactic tracheotomy), mechanical ventilation, and respiratory tract infections were the factors impacting the length of ICU stay of patients (ß=0.225, 0.008, 0.237, 0.203, -0.408, -0.334, 0.309, 0.523, 95% CI=0.053-0.502, 0.006-0.010, -0.018-0.457, -0.022-0.428, -0.575--0.241, -0.687--0.018, 0.132-0.486, 0.369-0.678, P<0.1). Multivariate linear regression analysis showed that with respiratory tract infections was the independent risk factor impacting the length of ICU stay of patients (ß=0.440, 95% CI=0.278-0.601, P<0.01). Single factor linear regression analysis showed that injury site, injurious factors of inhalation injury (smoke and chemical gas), combined total burn area, degree of inhalation injury (moderate and severe), tracheotomy (no tracheotomy and prophylactic tracheotomy), and respiratory tract infections were the factors impacting mechanical ventilation days of patients (ß=-0.300, 0.545, 0.163, 0.005, 0.487, 0.799, -0.791, -0.736, 0.300, 95% CI=-0.565--0.034, 0.145-0.946, 0.051-1.188, 0.001-0.009, 0.127-0.847, 0.436-1.162, -1.075--0.508, -1.243--0.229, 0.005-0.605, P<0.1). Multivariate linear regression analysis showed that smoke inhalation, severe inhalation injury, and respiratory tract infections were the independent risk factors impacting mechanical ventilation days of patients (ß=0.210, 0.495, 0.263, 95% CI=0.138-0.560, 0.143-0.848, 0.007-0.519, P<0.05 or P<0.01). Single factor logistic regression analysis showed that age, injury site, combined total burn area (10%-19%TBSA and 20%-29%TBSA), degree of inhalation injury (moderate and severe), tracheotomy (prophylactic tracheotomy and no tracheotomy), and mechanical ventilation were the factors impacting respiratory tract infections of patients (odds ratio=1.079, 0.815, 1.400, 1.331, 1.803, 1.958, 0.990, 0.320, 3.094, 95% CI=0.840-1.362, 0.641-1.044, 1.122-1.526, 1.028-1.661, 1.344-2.405, 1.460-2.612, 0.744-1.320, 0.241-0.424, 2.331-4.090, P<0.1). Multivariate logistic regression analysis showed that with mechanical ventilation was the independent risk factor impacting respiratory tract infections of patients (odds ratio=4.300, 95% CI=2.152-8.624, P<0.01). Conclusions: The patients with inhalation injuries combined with total burn area less than 30%TBSA are mainly young and middle-aged males. Smoke inhalation, degree of inhalation injury, with mechanical ventilation and respiratory tract infections are the factors that affect the outcomes of patients with inhalation injuries combined with total burn area less than 30%TBSA. Additionally, prophylactic tracheotomy shows its potential value in reducing respiratory tract infections in patients with moderate or severe inhalation injuries.

[Retrospective cohort study on the coagulation characteristics of adult patients with extensively severe burn in shock stage and its alarming value].

Objective: To study the coagulation characteristics of adult patients with extensively severe burn in shock stage and its alarming value. Methods: Retrospective cohort study was performed on medical records of 37 adult patients with extensively severe burn who were admitted to the First Affiliated Hospital of Naval Medical University from January 2014 to December 2019 and met the inclusion criteria. The patients were divided into survival group (n=23, 17 males and 6 females, aged 41 (31, 51) years) and death group (n=14, 11 males and 3 females, aged 50 (43, 58) years) according to the prognosis of within 60 d after burn. Basic data of patients in the two groups and their routine coagulation indexes during shock period including prothrombin time (PT), thrombin time, activated partial thromboplastin time (APTT), D-Dimer, fibrinogen degradation product (FDP), fibrinogen, platelet, and international normalized ratio (INR) were recorded. Data were statistically analyzed with Wilcoxon rank sum test and Fisher's exact probability test, prognosis-related factors was analyzed with single factor and multivariate logistic regression analysis (α selected=0.05, α excluded=0.1), and receiver operating characteristic (ROC) curve analysis were established to screen out the risk factors. All the patients were grouped into high score group and low score group according to the optimal threshold value, Kaplan-Meier method was used for survival analysis and Log-rank test was performed between the two groups. Results: Total burn surface area (TBSA) of patients in death group was obviously larger than that in survival group (Z=2.980, P<0.01), while there were no statistically significant difference in the other indexes between the two groups (P>0.05). Compared with those in survival group (16.10 (14.30, 16.90) s, 40.80 (36.20, 42.80) s, 1.30 (1.10, 1.40)), PT (18.70 (16.30, 22.70) s), APTT (46.45 (41.00, 57.10) s) and INR (1.55 (1.30, 1.96)) of patients in death group were significantly increased (Z=2.540, 2.330, 2.300, P<0.05), there were no statistically significant difference in the other indexes between the two groups (P>0.05). Single factor logistic regression analysis showed TBSA, PT, and APTT were factors related to death of adult patients with extensively severe burn within 60 d after burn (odds ratio (OR)=1.190, 1.214, 1.109, 95% confidence interval (CI)=1.053-1.346, 1.008-1.461, 1.012-1.215, P<0.05 or P<0.01). FDP and INR were potential factors related to death of adult patients with extensively severe burn within 60 d after burn (OR=1.040 and 4.559, 95% CI =0.998-1.083 and 0.918-22.641, P<0.1). Multivariate logistic stepwise regression was used to build models of APTT+ FDP+ TBSA and APTT+ FDP. Area under the curve (AUC) of APTT+ FDP+ TBSA model score was 0.944 (95% CI= 0.873-1.000), which was higher than AUC of APTT+ FDP model score (0.843, 95% CI=0.713-0.973) by ROC curve analysis. Optimal threshold value of APTT+ FDP+ TBSA model score was -0.879 4 with sensitivity of 100% (95% CI=100%-100%) and specificity of 87% (95% CI=74%-100%). Survival ratio of patients in high score group with optimal threshold value higher than -0.879 4 was significantly lower than that in low score group with optimal threshold value lower than -0.879 4, χ(2)=27.090, P<0.01. Conclusions: The coagulation state of adult patients with extensively severe burn in shock stage is characterized with procoagulant and hemostatic dysfunctions accompanied by enhanced fibrinolytic activity. The risk of death is significantly increased in adult patients with extensively severe burn with APTT+ FDP+ TBSA model score higher than -0.879 4.

[Value of joint prediction model based on the modified systemic inflammatory response syndrome score for predicting mortality risk of patients with large area burns at early stage after admission].

Objective: To investigate the predictive value of the joint prediction model based on the modified systemic inflammatory response syndrome (SIRS) score (hereinafter referred to as the joint prediction model) for the mortality risk of patients with large area burns within 24 hours after admission. Methods: The clinical data of 158 patients [111 males, 47 females, aged 40 (28, 50) years] admitted to the Department of Burn Surgery of the First Affiliated Hospital of Naval Medical University from January 2005 to January 2018, conforming to the study criteria, were analyzed retrospectively by the method of case-control study. The age, gender, total burn area, full-thickness burn area, injury cause, with or without inhalation injury, severity of inhalation injury, and tracheotomy condition of patients were recorded, and the modified SIRS score and the modified Baux score of patients were calculated. According to the final outcome, all patients were divided into survival group (n=123) and death group (n=35). The clinical data of patients between two groups, except for modified Baux score, were compared by chi-square test or Mann-Whitney U test to screen the death-related factors of patients. The indexes with statistically significant difference between the two groups were included in the multivariate logistic regression analysis to screen the independent risk factors related to the death of patients, and the prediction model was constructed by combining the modified SIRS score. The receiver's operating characteristic curves of the modified SIRS score, the modified Baux score, and the joint prediction model of 158 patients were drawn to analyze their ability to predict death of patients. The area under curve (AUC) of the receiver's operating characteristic and the sensitivity and specificity of optimal threshold were calculated, and the quality of AUC of the three prediction indexes was compared with Jonckheere-Terpstra test. Results: (1) There were statistically significant differences between the two groups in the modified SIRS score, age, total burn area, full-thickness burn area, severity of inhalation injury, with or without inhalation injury, and tracheotomy condition of patients (Z=-4.356, -3.568, -5.291, -6.052, -4.720, χ(2)=12.967, 19.692, P<0.01). (2) The modified SIRS score, age, full-thickness burn area were the independent risk factors for the death of patients with large area burn (odds ratio=2.699, 1.069, 1.029, 95% confidence interval=1.447-5.033, 1.029-1.109, 1.005-1.054, P<0.05). (3) The AUC of modified SIRS score, the joint prediction model, and the modified Baux score for predicting death of 158 patients within 24 hours after admission were 0.730, 0.879, and 0.895 respectively (95% confidence interval=0.653-0.797, 0.818-0.926, 0.836-0.938, P<0.01). The sensitivities of the three optimal threshold values to death prediction were 54.3%, 91.4%, and 82.9% respectively, while the specificities were 81.3%, 76.4%, and 84.6% respectively. The AUC quality of the joint prediction model was similar to that of the modified Baux score (95% confidence interval=-0.057-0.088, P>0.05), and both of them were significantly better than that of the modified SIRS score (95% confidence interval=0.072-0.259, 0.023-0.276, P<0.05 or P<0.01). Conclusions: Both the joint prediction model and the modified Baux score are considered to be good to predict the death rate of patients with large area burns at early stage after admission. However, the joint prediction model has better clinical practice value due to its advantage of simple scoring and easier access to data acquisition.

[Advances in the research of prevention and treatment of postburn contractures of hand].

Scar contracture deformity, which can lead to dysfunction of hand and low quality of life, is one of the common complication after hand burns. The prevention measures of scar contracture after hand burns include large skin grafting, prevention of infection, insistence on wearing pressure gloves, use of silicone sheets, wearing orthosis, accepting proper physical therapy, and early functional exercise. The primary treatments of postburn contractures of the hand are surgery, drugs, laser treatment, and rehabilitation therapy. Excision of scars, release of muscle, joints or bones, and soft tissue transplantation are the core of surgery. Laser treatment has a bright future but still needs to be further studied. Additionally, some novel treatments such as molecular targeted therapy, cell therapy, fat injection, and botulinum toxin injection will play important roles in prevention and treatment of postburn contractures in the future. The purpose of this article is to review the literature concerning postburn contractures of the hand, and summarize the present situation of prevention and treatment of such disease comprehensively.

A nine-year prospective study on the incidence of childhood type 1 diabetes mellitus in China.

To investigate the epidemiological characteristics of childhood type 1 diabetes mellitus in China, newly diagnosed cases of type 1 diabetes with an onset age under 15 years were retrospectively registered by 23 local centers in China following a standardized protocol on the basis of the nationwide registry established by the WHO DiaMond Project China Participating Center, Chinese Academy of Preventive Medicine (CAPM). A population of about 24 million children were covered in the defined areas. A two-sample capture-recapture method was used to estimate case ascertainment. Between 1988 and 1996, 903 diabetic cases were registered in 9 ethnic groups. The overall ascertainment corrected incidence rate (IR) was 0.59 per 100,000 person-year. The IR was 0.52/100,000 (95% CI: 0.50-0.54) for males and 0.66/100,000 (95% CI: 0.64-0.68) for females. The standardized ascertainment corrected IR by the national age-specific population in 1990 was 0.57 per 100,000 person-year. The incidence among various ethnic groups ranged from 0.25/100,000 to 3. 06/100,000. The IRs increased with northern latitude, and the IR of Han population was significantly higher in North China compared with South China (0.67 versus 0.53 per 100,000 respectively, P < 0.01). A correlation model of incidence and calendar time showed that the IR increased significantly between 1988 and 1996 (r = 0.86, P = 0.0027). The relative risk (RR) of type 1 diabetes mellitus for different age-groups estimated by a Poisson regression model showed that taking RR as 1.00 for age-group from 0 to 4 years, the RR for age-group from 5 to 9 year and from 10 to 14 year was 2.30 and 3.60 respectively. The standardized ascertainment corrected IR of childhood type 1 diabetes mellitus in China in much lower than in other countries. The geographic and ethnic variability of the incidence suggests that both genetic and environmental factors play a role in the development of childhood diabetes in China.

Costs of polio immunization days in China: implications for mass immunization campaign strategies.

Ten provinces of China were selected to estimate the cost per immunization of the 1994-95 national immunization days (NIDs) at five levels (e.g. province, prefecture, county, township and village). Personnel costs accounted for the largest overall share of costs (39 per cent), followed by publicity and promotion costs (27 per cent), and logistic costs (15 per cent). Without consideration of vaccine costs, the major part of NID expenses were shouldered at the township level, which paid for 47 per cent of all incremental costs, while county and village level covered 28 per cent and 18 per cent respectively. Estimation of average costs per immunization was 2.86 RMB yuan, or $0.34, including vaccine costs, buildings and equipment amortization and salaries at all levels. The factors affecting average cost of NID included the output volume, socio-economic development and geographic features. Various approaches were recommended: to intensify the productivity of time and staff, to employ alternative inexpensive manpower resources, to make the best use of publicity and social promotion, the expansion of the age groups and utilization of multi-intervention strategies. Good planning at township level was a decisive factor to ensure an effective NID conducted in an efficient manner. The average cost of China's NID was the lowest among all mass immunization campaigns ever documented. Much of the reduced average cost was attributable to economies of scale.

Status of the eradication of indigenous wild poliomyelitis in the People's Republic of China.

A large nationwide outbreak occurred in 1989-1990 in China, in which nearly 10,000 poliomyelitis cases were reported. After two rounds of oral poliovirus vaccine (OPV) supplemental activity in nearly every province in the 1992-1993 winter season, no wild poliovirus was detected in 1993 in 22 provinces in the middle of China that contained 86% of the population. During the first national immunization days (NIDs) conducted in December 1993 and January 1994, 83 million children 0-47 months of age were immunized. In 1994, wild poliovirus was identified in only 6 of 2397 children with stool specimens tested. After a second NID in December 1994 and January 1995, no wild poliovirus was detected in 1995 despite a very high level of virus surveillance. In summary, double-round mass supplemental OPV immunizations in children 0-3 years old in two consecutive winters eliminated wild poliovirus from 23% of the world's population (1.2 billion people).

Surveillance for polio eradication in the People's Republic of China.

A case-based virus surveillance system for wild poliovirus in China was developed. By 1993, all 30 provincial immunization units and, by 1994, all 29 provincial laboratories were sending computerized data to the national level. In 1993, a county-level, computerized map was operationalized that permitted visual monitoring of the progress of the polio eradication program every month by county. In 1993, wild poliovirus type 1 was detected in 8 provinces. Wild poliovirus mainly caused clusters of polio cases identified by a surveillance system that detected primarily clinical polio in children <5 years old (1 stool sample was collected on approximately 50% of reported cases). By 1995, the surveillance system had reached certification-like levels (80% of acute flaccid paralysis [AFP] patients with 2 stool specimens and AFP case rate of 1/100,000 children <15 years old). No indigenous wild poliovirus was detected in 1995. This general case-based model can be applied to measles and other important diseases, and may then lead to a more rapid decrease in adverse health outcomes.

Effect of target age of supplemental immunization campaigns on poliomyelitis occurrence in China.

The World Health Organization recommends conducting supplemental immunization activities to eradicate poliomyelitis by the year 2000. Although effective in eliminating poliomyelitis from the Americas, supplemental campaigns require substantial resources. To assess differential campaign effectiveness in eliminating this disease, poliomyelitis occurrence was compared in counties in China that targeted children <3 versus <4 years of age. Counties that targeted children <3 years of age reported poliomyelitis more frequently after the campaigns. This association was observed even after accounting for the effects of previous poliomyelitis occurrence, urban versus rural setting, and population density. While several limitations emphasize the preliminary nature of these findings, these data support targeting the widest possible age group of susceptible children to ensure maximum effectiveness in eliminating poliomyelitis. Thus, while reducing the target age of these activities may result in considerable resource savings, such campaigns may not be as effective in eliminating poliomyelitis.

The incidence of insulin-dependent diabetes mellitus in urban districts of Shanghai (1989-1993).

A retrospective study on the incidence of insulin-dependent diabetes mellitus (IDDM) among children aged 0-14 years was carried out from 1989-1993 in urban Shanghai, China. The average annual population at risk (0-14 yr) consisted of 1,401,664 children. All the cases were collected from the hospitals (primary source) and from primary and middle schools and kindergartens (second source) with independent validation of case ascertainment. There were 53 IDDM cases from the primary source, 23 from the secondary source, with a total of 58. The ascertainment corrected total number of IDDM cases was 67 by the capture-recapture method. The average crude annual incidence rate was 0.83 [95% confidence interval (CI) 0.61-1.04] and ascertainment corrected incidence rate 0.96 (95% CI 0.80-1.12) per 100,000. Peak incidence fell in 1992 and in the 9 year-old group. The incidence of childhood IDDM in the urban districts of Shanghai was reconfirmed to be the lowest in the world but by comparing the results of former investigations a trend was found of increasing incidence of IDDM.

[Epidemiological analysis on morbidity of acute flaccid paralysis (AFP) among children under 15 years old in 14 provinces of China].

Five investigations through analysis of hospital records on morbidity of Acute Flaccid Paralysis (AFP) among children under 15 years old in 14 provinces of China have currently been conducted. In this paper, data from a series of studies published in journals or reported to meetings was combined and analyzed based on Meta-Analysis. Comparisons have been made between AFP, poliomyelitis, Guillian-Barre Syndrome (GBS) and non-polio AFP morbidities and their distributions by age, sex and month. The morbidity rates for these four categories were 1.41, 0.54, 0.55 and 1.05 per 10(5) respectively. An important conclusion drawn from of this study was that the criterion put forward by WHO, reported rate of non-polio AFP should reach over 1.0 per 10(5) among children under 15, can also be used as an indicator for sensitivity evaluation and monitoring of AFP surveillance system in China.

[Seroepidemiological surveillance and methodological study of pertussis, diphtheria and tetanus].

In this paper, we studied the diagnostic method of DPT using PA method developed by Japanese National Institute of Health (NIH) in 1993-1994, meanwhile we surveyed the antibody level of DPT. We collected 900 sera samples and 300 sera samples from Hebei province in 1993 and 1994. The result showed that PA method was simple, reliable and easy to observe, which can make up the shortages existed in PHA method. The antitoxin titers obtained by the PA method correlated well with the PHA method, while the latter was more sensitive. The antibody level of pertussis obtained through PA method did not correlate well with MA method. The result also showed that the antibody level of DPT was not high, with a 95.0% positive rate of pertussis. The rate of titers higher than 1:320 was 4.7% with GMT 1:121; the positive rate of diphtheria was 62.9% with GMT 0.0280 IU/ml, in 1993 the positive rate of tetanus was 70.5% with GMT 0.1410 IU/ml, in 1994 the positive rate was 75.7% with GMT 0.3281 IU/ml. The titers in urban areas were higher than in rural areas and a decrease was observed with the increase of age. The titers in males was similar to in females. According to this result, a routine immunization followed by booster program should be emphasized.

A combinatorial approach to materials discovery.

A method that combines thin film deposition and physical masking techniques has been used for the parallel synthesis of spatially addressable libraries of solid-state materials. Arrays containing different combinations, stoichiometries, and deposition sequences of BaCO(3), Bi(2)O(3), CaO, CuO, PbO, SrCO(3), and Y(2)O(3) were generated with a series of binary masks. The arrays were sintered and BiSrCaCuO and YBaCuO superconducting films were identified. Samples as small as 200 micrometers by 200 micrometers in size were generated, corresponding to library densities of 10,000 sites per square inch. The ability to generate and screen combinatorial libraries of solid-state compounds, when coupled with theory and empirical observations, may significantly increase the rate at which novel electronic, magnetic, and optical materials are discovered and theoretical predictions tested.

Eradication of poliomyelitis: progress in the People's Republic of China.

China and the other countries of the Western Pacific Region have a goal of eradication of wild poliovirus by the end of 1995. In this report we examine the progress made toward eradication through the end of 1993. We examined the information about poliomyelitis and wild poliovirus based on the acute flaccid paralysis surveillance system. The number of reported poliomyelitis cases decreased from 4623 cases in 1989 and 5065 cases in 1990, which occurred during a large nationwide poliomyelitis epidemic, to 538 cases in 1993. Mass supplemental immunization sessions were conducted during the 1991 to 1992 and 1992 to 1993 winters. After the two rounds of supplemental immunizations in the 1992 to 1993 winter, wild poliovirus was not detected for the subsequent 21 months in 22 contiguous provinces in central and northern China, in which 980 million persons reside. In 1993 wild poliovirus was detected in only 5 provinces in southern China and in 2 provinces in the remote Western region; these provinces have only 14% of the total population in China. China is close to achieving its 1995 poliomyelitis elimination goal. Mass supplemental immunizations in children 0 to 3 years old can rapidly eliminate wild poliovirus from large, very densely populated areas, low income rural areas and remote mountainous areas. There appears to be no technical obstacle, even in the most difficult areas, to achieving global eradication of wild poliovirus by the year 2000.

Social aspects of malaria in Heping, Hainan.

This paper presents findings from a study conducted in Heping Town, Qiongzhong County, Hainan Province, China. The study, conducted in 1992, used qualitative as well as quantitative methods to gather social, cultural and behavioural data associated with the acquisition, transmission and prevention of malaria, and the diagnosis and treatment of disease. These methods included focus groups, key informant and other in-depth interviews, and observations, a household survey and tests of school children of knowledge of malaria. The study is among the first to our knowledge that has utilized this broad mix of methods for tropical disease research in China.

PIP: Malaria continues to be a major public health problem worldwide. Although there is only a low level of malaria endemicity in China, Hainan Island is endemic for malaria. Qiongzhong County was long hyperendemic for malaria. The authors used focus groups, key informant and other in-depth interviews, observations, a household survey, and tests of school children knowledge of malaria to gather social, cultural, and behavioral data associated with the acquisition, transmission, and prevention of malaria, and the diagnosis and treatment of disease in six villages of Heping Town and three production teams of Chengpo Farm, Qiongzhong County. This 1992 study is groundbreaking in its use of such a broad array of methods to research tropical disease in China. Findings are based upon the input of 1100 persons in 226 households. The open walls of the bamboo-slat houses allow easy mosquito access, but the cost of more substantial, and protective, housing is beyond the means of most villagers. The study found no statistically significant association between literacy and bed net use, while income was neither predictive of nor related to bed net use. Some malaria knowledge and being younger than ten years old were, however, predictive of bed net use. Residents tend to use bed nets without understanding the rationale for such behavior. They do so in adherence to the general message that bed nets will prevent mosquito bites. The authors note the need to address the odor and heat discomfort from sleeping under bed nets, the lack of association among villagers between net use and disease prevention, the lack of understanding that mosquitoes are the vector of malaria, confusion between general health status and vulnerability to malaria infection, the nature of sleeping patterns by sex, and the lack of understanding that one bite suffices to transmit disease.

Multidimensional narrow bore liquid chromatography analysis of Ro 24-0238 in human plasma.

A highly sensitive LC method has been developed and validated for quantitation of Ro 24-0238 in human plasma using Ro 24-2446 as an internal standard. With 1 ml of plasma, the limit of quantitation of the method was 50 pg ml-1 of Ro 24-0238. After solid-phase extraction with C18 reversed-phase cartridges, the samples were reconstituted in an acidic buffer solution; under these conditions, Ro 24-0238 and Ro 24-2446 (IS) were converted to their cationic forms. The LC system employed a strong cation exchange column and a narrow bore reversed-phase column, connected via a column switching valve. The cationic analyte and internal standard were separated from most of the endogenous components of plasma on the cation exchange column. A small fraction containing the analyte and the internal standard was transferred by automated valve switching to the narrow bore reversed-phase column, which further resolved the individual components. The chromatography was monitored by UV absorption at 322 nm. The overall intra-assay precision was 3.6% (RSD) and the per cent error was less than +/- 11%. The overall inter-assay precision was 3.9% (RSD). Linearity was demonstrated in a concentration range of 50-5000 pg ml-1. This method has been applied to pharmacokinetic studies of Ro 24-0238 in man.