Spectrum of cutaneous granulomatous lesions: A 5-year experience in a tertiary care centre in Sarawak.

INTRODUCTION: Granulomatous skin lesions can have various histopathological features leading to diagnostic confusion. The study aimed to determine the frequency and pattern of different granulomatous skin lesions. MATERIALS AND METHODS: This was a 5-year retrospective study done between April 2017 and March 2022 at Dermatology Department, Sarawak General Hospital. Subjects with a clinicopathological diagnosis of granulomatous diseases were included in the analysis. RESULTS: A total of 1718 skin biopsies were done during the study periods, with 49 (2.8%) confirmed granulomatous skin lesions. Most patients were aged 40-60 with a male predominance of 51%. Most of the skin biopsy samples were taken from the upper limb (36%). In this study, epitheloid granuloma was the commonest subtype (21, 43%) followed by suppurative granuloma (12, 24%), tuberculoid granuloma (8, 16%) and foreign body granuloma (5, 10%). The commonest aetiology of granulomatous skin lesions in our study was infections (30, 61%) followed by foreign body inoculation (8, 16%). Fungal infection was the most common infective cause, followed by cutaneous tuberculosis. CONCLUSION: The major cause of granulomatous dermatoses in developing countries is still infections, fungal and tuberculosis being the leading causes.

Comparison of amino acid digestibility and its additivity determined with slaughter or cecectomy method for yellow-feather chicken.

The objective of this experiment was to compare the slaughter and cecectomy methods to determine amino acid (AA) digestibility of corn and soybean meal and their additivity in a corn-soybean meal diet. A completely randomized design was adopted to determine endogenous AA losses (EAAL) and AA digestibility in each of corn, soybean meal, and a corn-soybean meal diet using either slaughter or cecectomy methods. Each treatment contained 6 replicates with 3 chickens per replicate. The endogenous loss (EL) of histidine and glycine was lower and the EL of methionine and phenylalanine was greater when determined by slaughter vs. cecectomy (P < 0.05). The EL of arginine, isoleucine, leucine, lysine, methionine, phenylalanine, valine, alanine, aspartic acid, glutamic acid, and serine determined by slaughter were 1.2 to 3.2 times of those from cecectomy. The standard error (SE) of EL of 14 AA (excluding histidine and glycine) obtained by slaughter method was 2.1 to 9.6 times of those by cecectomy method. The apparent and standardized digestibility was not affected by methods for most AA except apparent digestibility of methionine, phenylalanine and glycine, and standardized digestibility of glycine in corn. The apparent and standardized digestibility of most AA except apparent digestibility of glycine and standardized digestibility of lysine, cysteine and glycine were less for slaughter versus cecectomy methods in soybean meal (P < 0.05). Using slaughter method resulted in reduced apparent digestibility of 15 AA (except glycine) and reduced standardized digestibility of 7 AA (arginine, isoleucine, leucine, valine, aspartic acid, glutamic acid, and proline) relative to cecectomy method (P < 0.05), but the standardized digestibility of glycine was greater when determined by slaughter vs. cecectomy methods in corn-soybean meal diet (P < 0.05). The mean value of SE of 16 AA digestibility in slaughter method was 2.9 times of that by cecectomy method. The apparent digestibility of 2 and 9 of 16 AA and the standardized digestibility of 15 and 7 of 16 AA were additive when using slaughter and cecectomy determinations, respectively. In conclusion, compared to the slaughter method, cecectomy method had less SE and EAAL but greater apparent digestibility of methionine and phenylalanine in corn, and the apparent digestibility of 15 AA (except glycine) in soybean meal and corn-soybean meal diet. Additivity in apparent and standardized AA digestibility was more inconsistent when determined with slaughter vs. cecectomy methods. These findings suggest that the cecectomy method is more suitable than the slaughter method to determine the digestibility of AA.

[Morphological and molecular identification of trematode isloates from laying ducks in Nanchang City].

OBJECTIVE: To identify the species of trematodes isolated from laying ducks in Nanchang City using morphological and molecular approaches. METHODS: Trematodes were isolated from the hepatobiliary duct, gallbladder and large intestine of market-sold laying ducks in Nanchang City. Following morphological characterization, total DNA was extracted from all trematode specimens, and internal transcribed spacer region (ITS) and cytochrome C oxidase subunit 1 (Cox1) genes were amplified using PCR assay and sequenced. Sequence alignment was performed using the Blast software, and homology and phylogenetic analyses were done in the trematode isolates based on ITS and Cox1 gene sequences. RESULTS: The morphological characteristics of two trematode isolates from the large intestine of laying ducks were similar to those of Echinostoma revolutum and E. miyagawai, and the morphological characteristics of eight trematode samples isolated from the hepatobiliary duct and gallbladder of laying ducks were similar to those of Amphimerus anatis. The ITS and Cox1 gene sequences of the two trematode isolates from the large intestine of laying ducks had 99.3% and 98.9%-99.4% homology with E. miyagawai, and the phylogenetic analysis showed that two trematode isolates had the closest genetic relationship with E. miyagawai based on ITS and Cox1 gene sequences. The ITS gene sequences of eight trematode isolates from the hepatobiliary duct and gallbladder of laying ducks shared 95.1%-95.5% with Opisthorchis sudarikovi and Clonorchis sinensis, while the Cox1 gene sequences of eight trematode isolates from the hepatobiliary duct and gallbladder of laying ducks shared 86.3%-86.4% and 85.5%-85.7% with O. viverrini and O. sudarikovi. ITS gene sequence-based phylogenetic analysis showed that the duck-derived trematode isolates had the closest genetic relationship with C. sinensis, and Cox1 gene sequence-based phylogenetic analysis showed that the duck-derived trematode isolates had the closest genetic relationship with Metorchis orientalis and O. viverrini. CONCLUSIONS: The trematode isolates from the large intestine of laying ducts in Nanchang City may be E. miyagawai, and the trematode isolates from the hepatobiliary duct and gallbladder may be an unidentified trematode species of the family Opisthorchiidae.

[Comparison of training models for master of public health between China and other countries].

With the accelerating globalization and the implementation of "Belt and Road" initiative proposed by our government, communication and exchanges between China and foreign countries have become more and more frequent than before, and much more international students have chosen to study in China's universities as candidates of master of public health (MPH). However, because China only launched the MPH program in recent years, with the training models being highly similar to the program of master of science in China but quite different from those of main international MPH programs, hindering China's MPH program to become an international one. This paper systematically evaluated existing training models of MPH programs both at home and abroad through literature review and identified major differences and deficiencies of China's MPH program compared to those from other countries: (1) requirement for medical background only; (2) comparatively longer period to complete the program; (3) incomplete curriculum; (4) overemphasizing scientific research competencies but somewhat neglecting practical abilities; and (5) limited career choices, and put forward some suggestions to improve the MPH program of China, including removing requirement for medical background only, shortening the period of MPH program, improving the curriculum of MPH program, and enhancing the training of practical abilities.

[Machine learning and its epidemiological applications].

As an important branch of artificial intelligence, machine learning is widely used in various fields. Machine learning has similarity to classical statistical methods, but can solve many problems which are difficult for traditional statistics, so it is one of the important tools in epidemiological research. This paper introduced 9 common algorithms of machine learning and summarized their characteristics and applications in epidemiological research. Readers could choose appropriate machine learning method according to the research purpose for the better application of machine learning in epidemiological research.

Research Note: Effect of dietary cottonseed meal and soybean oil concentration on digesta passage time and amino acids digestibility in roosters.

Two experiments were conducted to study the effect of dietary cottonseed meal (CM) and soybean oil (SO) on passage time of digesta and standardized ileal digestibility (SID) of amino acids (AA). The experimental design was a 2 × 2 factorial arrangement evaluating the levels of CM (20 or 40 %) and SO (0 or 10 %). Experiment 1 estimated the effect of CM and SO on the passage time of digesta. Twenty-five Chinese yellow-feathered roosters (BW = 2.61 ± 0.08 kg; 26-wk-old) were individually weighed and allocated to 5 diets in 5 randomized complete blocks by initial BW. Experimental diet 1 contained 20% CM and 0 SO, diet 2 contained 20% CM and 10% SO, diet 3 contained 40% CM and 0% SO, diet 4 contained 40% CM and 10% SO, and a nitrogen-free diet was also fed. Passage time through the total digestive tract was determined by time-relative cumulation of dry excreta. Experiment 2 estimated the effect of CM and SO on SID of AA in CM. Thirty Chinese yellow-feathered roosters (BW = 2.91 ± 0.05 kg; 26-wk-old) were allocated to the 5 experimental diets in 6 randomized complete blocks by initial BW to determine the SID of AA. Increasing CM concentration significantly reduced the time for 50% relative cumulation of dry excreta (P < 0.05). Adding 10% SO tended to increase the time for 50% relative cumulation of dry excreta (0.05 < P < 0.10) relative to diets without SO. Dietary CM and SO did not affect the SID of indispensable AA or dispensable AA of CM significantly, but increasing dietary CM tended to reduce the SID of Lys (0.05 < P < 0.10). Increasing SO tended to reduce the SID of Met (0.05 < P < 0.10). There were no significant interactive effects of SO and CM (P > 0.10). These results suggest passage time is increased with dietary SO, and reduced with dietary CM, but digestibility of AA in CM was not significantly affected by dietary CM and SO.

Sensitivity of in vitro digestible energy determined with computer-controlled simulated digestion system and its accuracy to predict dietary metabolizable energy for roosters.

Two experiments were conducted to validate the sensitivity and accuracy of in vitro digestible energy (IVDE) determined with a computer-controlled simulated digestion system (CCSDS) to predict metabolizable energy (ME) of diets for roosters. In experiment 1, soybean hulls were added to a basal diet (calibration diet 1) at 2.06, 4.12, 6.17, 8.23, 10.28, 12.32, or 14.37% of the diets (calibration diets 2-8) to produce an interval of approximately 80 kcal ME/kg. The sensitivity was measured by comparing the determined and actual IVDE of the diets. With these data, a linear model was developed to predict ME from IVDE. In experiment 2, validation diets were identical except they were composed of different cereal ingredients. For each diet, the correlations and ratios between IVDE and ME were analyzed to test the sensitivity of IVDE to predict ME across different ingredients. In experiment 1, a slope of 0.9899 was calculated in a linear regression of determined IVDE on actual IVDE (R2 = 0.9998; P < 0.01). The ratio of determined IVDE to actual IVDE was 0.9878. The ratio of IVDE to apparent metabolizable energy (AME) and to nitrogen-corrected AME (AMEn) was 1.03 and 1.05, respectively. The linear models to predict ME from IVDE were AME = 0.8449 × IVDE + 451 (R2 = 0.9812, residual standard deviation [RSD] = 28 kcal/kg; P < 0.01) and AMEn = 0.8357 × IVDE + 436 (R2 = 0.9821, RSD = 27 kcal/kg; P < 0.01). In experiment 2, a significant simple correlation was observed between the IVDE and AME or AMEn of validation diets (r > 0.97; P < 0.01). The ratio of IVDE to AME and to AMEn was 1.04 and 1.05, respectively. Predicted and determined AME or AMEn of 8 validation diets differed by less than 100 kcal/kg. The regression of determined AME or AMEn against predicted AME or AMEn (R2 ≥ 0.9466; P < 0.01) resulted in an overlapped line where Y = X. These results suggest the IVDE determined with CCSDS is highly sensitive and can be used to accurately predict the ME of diets for roosters across a wide range of cereal grains.

Understanding the dynamics of COVID-19; implications for therapeutic intervention, vaccine development and movement control.

The COVID-19 disease is caused by the SARS-CoV-2 virus, which is highly infective within the human population. The virus is widely disseminated to almost every continent with over twenty-seven million infections and over ninety-thousand reported deaths attributed to COVID-19 disease. SARS-CoV-2 is a single stranded RNA virus, comprising three main viral proteins; membrane, spike and envelope. The clinical features of COVID-19 disease can be classified according to different degrees of severity, with some patients progressing to acute respiratory distress syndrome, which can be fatal. In addition, many infections are asymptomatic or only cause mild symptoms. As there is no specific treatment for COVID-19 there is considerable endeavour to raise a vaccine against SARS-CoV-2, in addition to engineering neutralizing antibody interventions. In the absence of an effective vaccine, movement controls of varying stringencies have been imposed. Whilst enforced lockdown measures have been effective, they may be less effective against the current strain of SARS-CoV-2, the G614 clade. Conversely, other mutations of the virus, such as the Δ382 variant could reduce the clinical relevance of infection. The front runners in the race to develop an effective vaccine focus on the SARS-Co-V-2 Spike protein. However, vaccines that produce a T-cell response to a wider range of SARS-Co-V-2 viral proteins, may be more effective. Population based studies that determine the level of innate immunity to SARS-CoV-2, from prior exposure to the virus or to other coronaviruses, will have important implications for government imposed movement control and the strategic delivery of vaccination programmes.

[An epidemiologic thinking on the diagnosis criteria of COVID-19].

The diagnosis of COVID-19 is based on the positive of etiological test. The current etiological test of COVID-19 cost long time, and have high false negative rate, may resulting delay the measures of disease treatment and prevention. We suggested that COVID-19 should be diagnosed as 3 types: suspected case, clinical diagnosed case, and definite diagnosed case.

[A sequential conditional mean model for assessing total effects of exposure in longitudinal data].

In prospective cohort study, multi follow up is often necessary for study subjects, and the observed values are correlated with each other, usually resulting in time-dependent confounding. In this case, the data generally do not meet the application conditions of traditional multivariate regression analysis. Sequential conditional mean model (SCMM) is a new approach that can deal with time-dependent confounding. This paper mainly summarizes the basic theory, steps and characteristics of SCMM.

[The association between the whole blood riboflavin level and the occurrence, development and prognosis of esophageal squamous cell carcinoma].

Objective: To investigate the association between the whole blood riboflavin level and the occurrence, development and prognosis of esophageal squamous cell carcinoma (ESCC) in China. Methods: From March 2014 to September 2018, ESCC patients from three hospitals (the Affiliated Hospital of Medical College of Shantou University, Shantou Central Hospital in Southern Chaoshan area and First Affiliated Hospital of Zhengzhou University in Northern Taihang Mountain) were selected as a case group; non-esophageal patients who had a physical examination were selected as a control group. The case and control group were paired by age (±5 years) and a 1:1 ration. A total of 1 528 subjects were enrolled including 764 patients in the case group and 764 patients in the control group. About 3-5 ml venous blood samples were collected, and the erythrocyte glutathione reductase activity coefficient (GRAC) was measured to assess the whole blood riboflavin level. A multivariate conditional logistic regression model was used to analyze the association between the GRAC and the risk of ESCC. The association between the GRAC and the prognosis of ESCC was analyzed by using Cox proportional risk regression model based on 288 patients with complete survival data. They were divided into two groups, the high GRAC group (GRAC≥7.87) group and the low GRAC group (GRAC<7.87) according to the strongest correlation between the total survival time, survival outcome and GRAC (GRAC=7.87). Results: Among the 1 528 patients, 958 patients were from Southern Chaoshan area, including 479 patients in the case group with an average age about (59.90±9.34) years and 479 patients in the control group with an average age about (59.55±8.77) years. Other 570 patients were from Northern Taihang Mountain area, including 285 patients in the case group with an average age (58.39±5.19) years and 285 patients in the control group with an average age about (58.74±4.57) years. The multivariate conditional logistic regression showed that the OR (95%CI) of the GRAC and the risk of ESCC was 1.009 (0.998-1.019). The Cox proportional hazard regression model analysis showed that the HR (95%CI) of the high GRAC group was 1.712 (1.034-2.824) compared with the low GRAC group in the 50-70 years group. Conclusion: The whole blood riboflavin level might not be associated with the occurrence of ESCC. The high whole blood riboflavin level would be more beneficial to the prognosis of ESCC patients aged 50-70 years.

[A new mediation analysis method for multiple mediators].

Mediation analysis is mainly used to explore the causal mechanism between independent variable X and dependent variable Y. It determines whether mediator M plays a role and evaluate the role's degree in the causal path by decomposing the causal path between the independent variable X and the dependent variable Y. However, the classical mediation analysis is generally used for single mediator. This paper introduces a new mediation analysis method for multiple mediators.

[Application of parametric g-formula in causal analysis].

At present, traditional methods on statistics have limitations in controlling time- varying confounding. This paper introduces an analysis method, parametric g-formula, which would adjust time-varying confounding, and also exemplifies the steps of its implementation for purpose to provide a new reference for researchers to deal with long-term observational data.

Infections in hospitalized lupus nephritis patients: characteristics, risk factors, and outcomes.

Background There are limited studies documenting infection epidemiology in lupus nephritis (LN) patients. We aimed to study infection incidences and risk characteristics and ascertain possible predictors of infective outcomes in a multiethnic Asian population. Methods This retrospective study from 2006 to 2012 included newly diagnosed LN patients. We collected admissions, immunosuppression, and infection data until end-stage renal failure, death, last follow-up, or the year 2015. The infection incidence rates were evaluated and a generalized linear latent and mixed models (GLLAMM) analysis was carried out to evaluate potential predictors of infection. Results Our cohort of 101 patients consisted of mainly Chinese (75.2%), females (78.2%), and a median age of 38 years (IQR 26-49). The median time of follow-up was 72.8 months (IQR 49.5-94.0). Six out of 14 patient deaths were infection related. Seventy-eight out of 200 admissions, with a total of 102 episodes of infection, occurred in 46 patients. The incidence of infection rates leading to admissions was 10.3 per 100 person-years and the incidence of infection episodes rates was 17.6 per 100 person-years. Cytomegalovirus (CMV) was the most common organism identified. Univariate GLLAMM analysis showed Malay compared to Chinese ethnicity (HR 2.833 (95% CI 1.088-7.373)), use of oral cyclophosphamide (HR 6.618 (95% CI 1.015-43.154)) and rituximab (HR 3.967 (95% CI 1.157-13.603)) as predictors of infection-related admissions. Malay ethnicity and rituximab remained significant in the multivariate GLLAMM analysis. Conclusions Our study highlights substantial infection incidences in patients with LN and its contribution to deaths.

[Dynamic path analysis on life course epidemiology].

In the studies of modern epidemiology, exposure in a short term cannot fully elaborate the mechanism of the development of diseases or health-related events. Thus, lights have been shed on to life course epidemiology, which studies the exposures in early life time and their effects related to the development of chronic diseases. When exploring the mechanism leading from one exposure to an outcome and its effects through other factors, due to the existence of time-variant effects, conventional statistic methods could not meet the needs of etiological analysis in life course epidemiology. This paper summarizes the dynamic path analysis model, including the model structure and significance, and its application in life course epidemiology. Meanwhile, the procedure of data processing and etiology analyzing were introduced. In conclusion, dynamic path analysis is a useful tool which can be used to better elucidate the mechanisms that underlie the etiology of chronic diseases.

Analysis of the effect of bacterial lysate and the immunologic mechanism in treating infant bronchiolitis.

OBJECTIVE: We studied the effect of bacterial lysate and the immunologic mechanism in treating infant bronchiolitis. PATIENTS AND METHODS: 124 infants were diagnosed with bronchiolitis were consecutively selected and randomly divided into control group and observation group, with 62 cases in each group. Conventional therapies were administered in the control group, while bacterial lysates were administered in the observation group. Therapeutic effects were compared after 14 days. RESULTS: In the control group, the total effective rate experienced prominent increase and the healing period was shortened. The differences were statistically significant (p < 0.05). Comparison of the reverse reactions in two groups showed no statistical difference (p > 0.05). Levels of serum IFN-γ, IL-4, NF-κB and KBD-1 after treatment showed no prominent changes in the control group. Levels of IFN-γ and Hbd-1 increased while levels of IL-4 and NF-κB decreased in the observation group; the differences were statistically significant (p < 0.05). Comparisons of the indexes above mentioned after treatment in the two groups showed significant differences (p < 0.05). Levels of IgA, IgG and IgM after treatment in the control group showed no changes, as well as the level of IgM in the observation group. Levels of IgA and IgG after treatment in the observation group prominently increased and were higher than that in the observation group; the differences were statistically significant (p < 0.05). CONCLUSIONS: Bacterial lysate can improve the therapeutic effect of infant bronchiolitis; it can also improve the level of certain cytokines, immunoglobulins, and strengthening immunity.

[Survey of economic burden of hepatitis B-related diseases in 12 areas in China].

Objective: Less surveys on the economic burden of hepatitis B (HB)-related diseases have been conducted in China, so the socioeconomic harm caused by the diseases is not clear and the key parameters for economic evaluation of hepatitis B prevention and treatment are lacking. This study aimed to analyze the direct, indirect and intangible expenditures of hospitalized patients with HB-related diseases during hospitalization and during a year in different areas of China. Methods: The hospitals for infectious diseases and the large general hospitals in 12 areas in China were selected in the study. All the inpatients with HB-related diseases were surveyed by cluster sampling of consecutive cases. The direct expenditure included direct medical cost and direct non-medical cost. The indirect expenditure, including work loss of patients and caregivers, were calculated by using human capital method for urban and rural populations in 12 areas. The intangible expenditure were reflected by willing to pay and stochastic tournament. The influencing factors of direct and indirect costs were identified by stepwise linear multi-variation regression analysis. Results: A total of 27 hospitals in 12 areas were included in the survey. A total of 4 718 cases were surveyed, the overall response rate was 77.7%. The average hospital stay was 29.2 days (27-34) and the hospitalization expenditure was averagely 16 832.80 yuan (RMB) per case, in which the highest proportion (61.2%) was medicine fees [10 365.10 yuan (RMB)]. The average direct expenditure and indirect expenditure were consistent with the severity of illness, which were 18 336.10 yuan (RMB) and 4 759.60 yuan (RMB) respectively, with the ratio of 3.85 ∶ 1. The direct medical expenditure [17 434.70 yuan (RMB)] were substantially higher than the direct non-medical expenditure [901.40 yuan (RMB)]. It was found that the hospitalization expenses was highest in direct medical expenditure and the transportation expenses was highest in direct non-medical expenditures. Among the average indirect expenditure, the loss of income for the patients [3 832.50 yuan (RMB)] was higher than that for the caregivers [927.20 yuan (RMB)]. The total direct and indirect expenditure was highest for liver transplantation, followed by severe hepatitis, hepatocellular carcinoma and decompensated cirrhosis, acute hepatitis B, compensated cirrhosis and chronic hepatitis B. The influencing factors for both direct and indirect expenditure were high hospital level, severity of hepatitis B, living in urban area, antiviral therapy, long hospitalization and monthly income of family. For average 3.74 outpatient visits and 1.51 hospitalization, the average annual direct, indirect and intangible expenditure for HB-related diseases were 30 135.30, 6 253.80 and 44 729.90 yuan (RMB) [totally 81 119.00 yuan (RMB)], accounting for 37.3%, 7.7% and 55.0%, respectively. Of the annual direct medical expenditure [28 402.80 yuan (RMB)], which were much higher than non-medical expenditure [1 732.50 yuan (RMB)], hospitalization expenditure [26 074.20 yuan (RMB)] was higher than outpatient visit expenditure [4 061.10 yuan (RMB)]. The annual indirect expenditures for outpatient visit and hospitalization were 763.60 and 5 490.10 yuan (RMB), respectively. Of the annual intangible expenditure, the highest was that for primary hepatocellular carcinoma, followed by cirrhosis, chronic hepatitis B, severe hepatitis B, liver transplantation and acute hepatitis B. Conclusions: A heavy economic burden has been caused by HB-related diseases in China, and patients are more likely to rely on medical service rather than non-medical service. It is necessary to take effective treatment measures to prevent the adverse outcome of HB related diseases and achieve significant economic benefits. The influence of HB related diseases on mental health of the people can be reflected by an economics term, intangible expenditure.

[Research of prevalence of schistosomiasis in Hunan province, 1984-2015].

Objective: To analyze the prevalence of schistosomiasis in Hunan province, and provide scientific evidence for the control and elimination of schistosomiasis. Methods: The changes of infection rates of Schistosoma (S.) japonicum among residents and cattle in Hunan from 1984 to 2015 were analyzed by using dynamic trend diagram; and the time regression model was used to fit the infection rates of S. japonicum, and predict the recent infection rate. Results: The overall infection rates of S. japonicum in Hunan from 1984 to 2015 showed downward trend (95.29% in residents and 95.16% in cattle). By using the linear regression model, the actual values of infection rates in residents and cattle were all in the 95% confidence intervals of the value predicted; and the prediction showed that the infection rates in the residents and cattle would continue to decrease from 2016 to 2020. Conclusion: The prevalence of schistosomiasis was in decline in Hunan. The regression model has a good effect in the short-term prediction of schistosomiasis prevalence.

Kinetics of phosphorus absorption in ligated small intestinal segments of broilers.

Two experiments were conducted using 22-d-old Arbor Acres male broilers to study the kinetics of inorganic P absorption and the effect of P treatment on Type IIb sodium-phosphate cotransporter (NaP-IIb) mRNA and protein levels in ligated segments from different intestinal regions. In Exp. 1, the P absorption in different small intestinal segments at different postperfusion times (0, 2.5, 5, 10, 20, or 40 min) were compared. In Exp. 2, different small intestinal loops were perfused with solutions containing 0, 1.5, 3, 6, 12, 24, or 48 mmol P/L as KHPO, and P concentrations in perfusates were determined at 20 min after perfusion. The mRNA levels of NaP-IIb in different small intestinal loops and protein expression levels in the duodenums from the control group and the 6 or 48 mmol P/L group were analyzed. The results from Exp. 1 showed that P absorption increased in an asymptotic response to postperfusion time within 40 min in all the intestinal segments and P absorption was greater ( < 0.04) in the duodenum than in the other 2 segments at 20 min after perfusion, indicating that the duodenum is the main site of P absorption in the small intestine of chicks. In Exp. 2, the kinetic curves showed that P absorption in the duodenum was a saturated carrier mediated process and in the jejunum or ileum occurred with a nonsaturated diffusion process. In addition, the b mRNA levels were greater ( < 0.0001) in the duodenum than in the other 2 segments in the 3 groups (0, 6, or 48 mmol P/L), further indicating that P absorption in the duodenum occurred mainly by a saturated carrier mediated process. However, no significant differences ( = 0.20) in the NaP-IIb protein levels of the duodenum were observed among the 0, 6, and 48 mmol P/L groups. In conclusion, this study suggests by our criteria in ligated intestinal loops that the duodenum is the main site of P absorption and that P absorption may be a saturated carrier mediated process in the duodenum but a nonsaturated diffusion process in the jejunum or ileum of broilers.