Predictive and Prognostic Potentials of Lymphocyte-C-Reactive Protein Ratio Upon Hospitalization in Adult Patients with Acute Pancreatitis

Purpose

In this study, our objective was to investigate the potential utility of lymphocyte-C-reactive protein ratio (LCR) as a predictor of disease progression and a screening tool for intensive care unit (ICU) admission in adult patients with acute pancreatitis (AP).

Methods

We included a total of 217 adult patients with AP who were admitted to the First Affiliated Hospital of Harbin Medical University between July 2019 and June 2022. These patients were categorized into three groups: mild AP (MAP), moderately severe AP (MSAP), and severe AP (SAP), based on the presence and duration of organ dysfunction. Various demographic and clinical data were collected and compared among different disease severity groups.

Results

Height, diabetes, lymphocyte count (LYMPH), lymphocyte percentage (LYM%), platelet count (PLT), D-Dimer, albumin (ALB), blood urea nitrogen (BUN), serum creatinine (SCr), glucose (GLU), calcium ion (Ca2+), C-reactive protein (CRP), procalcitonin (PCT), hospitalization duration, ICU admission, need for BP, LCR, sequential organ failure assessment (SOFA) score, bedside index for severity in AP (BISAP) score, and modified Marshall score showed significant differences across different disease severity groups upon hospitalization. Notably, there were significant differences in LCR between the MAP group and the MSAP and SAP combined group, and the MAP and MSAP combined group and the SAP group, and adult AP patients with ICU admission and those without ICU admission upon hospitalization.

Conclusion

In summary, LCR upon hospitalization can be utilized as a simple and reliable predictor of disease progression and a screening tool for ICU admission in adult patients with AP.

Dynamic lymphocyte-CRP ratio as a predictor: a single-centre retrospective study on disease severity and progression in adult COVID-19 patients

OBJECTIVE

To assess the efficacy of dynamic changes in lymphocyte-C-reactive protein ratio (LCR) on differentiating disease severity and predicting disease progression in adult patients with Coronavirus disease 2019 (COVID-19).

METHODS

This single-centre retrospective study enrolled adult COVID-19 patients categorized into moderate, severe and critical groups according to the Diagnosis and Treatment of New Coronavirus Pneumonia (ninth edition). Demographic and clinical data were collected. LCR and sequential organ failure assessment (SOFA) score were calculated. Lymphocyte count and C-reactive protein (CRP) levels were monitored on up to four occasions. Disease severity was determined concurrently with each LCR measurement.

RESULTS

This study included 145 patients assigned to moderate (n = 105), severe (n = 33) and critical groups (n = 7). On admission, significant differences were observed among different disease severity groups including age, comorbidities, neutrophil proportion, lymphocyte count and proportion, D-Dimer, albumin, total bilirubin, direct bilirubin, indirect bilirubin, CRP and SOFA score. Dynamic changes in LCR showed significant differences across different disease severity groups at different times, which were significantly inversely correlated with disease severity of COVID-19, with correlation coefficients of -0.564, -0.548, -0.550 and -0.429 at four different times.

CONCLUSION

Dynamic changes in LCR can effectively differentiate disease severity and predict disease progression in adult COVID-19 patients.

[Epidemiological characteristics of mpox epidemic in Guangzhou]

Objective: To understand the epidemiological characteristics of mpox epidemic in Guangzhou and provide scientific evidence for the prevention and control of the disease. Methods: Based on the mpox surveillance system in Guangzhou, suspected mpox cases with fever and rash were reported by local hospitals at all levels to centers for disease control and prevention in Guangzhou for sampling, investigation and diagnosis. Descriptive epidemiological analysis was conducted on the clinical characteristics and treatment of the mpox cases and positive detection rate reported in Guangzhou as of 24:00 on June 23. Whole genome sequencing of the virus isolates was performed using Illumina Miniseq high-throughput sequencing platform. Results: The first mpox case in Guangzhou was reported on June 10 in 2023. As of 24:00 on June 23, a total of 25 confirmed mpox cases were reported. All the mpox cases were men with a M(Q1,Q3) of 32 (26, 36) years, the majority of the cases were MSM (96.0%). The main clinical features were rash (100.0%, 25/25), lymphadenectasis (100.0%, 25/25) and fever (52.0%, 13/25). Rash usually occurred near the genitals (88.0%, 22/25). The close contacts, mainly family members (40.4%, 23/57), showed no similar symptoms, such as fever or rash. The positive rate of mpox virus in household environment samples was 30.5%. The analyses on 3 complete gene sequences of mpox virus indicated that the strains belonged to West African type Ⅱb clade, B.1.3 lineage. Conclusions: Hidden transmission of mpox virus had occurred in MSM in Guangzhou. However, the size of affected population is relatively limited, and the possibility of wide spread of the virus is low.

Efficient methods for multiple types of precise gene-editing in Chlamydomonas

Precise gene-editing using CRISPR/Cas9 technology remains a long-standing challenge, especially for genes with low expression and no selectable phenotypes in Chlamydomonas reinhardtii, a classic model for photosynthesis and cilia research. Here, we developed a multi-type and precise genetic manipulation method in which a DNA break was generated by Cas9 nuclease and the repair was mediated using a homologous DNA template. The efficacy of this method was demonstrated for several types of gene editing, including inactivation of two low-expression genes (CrTET1 and CrKU80), the introduction of a FLAG-HA epitope tag into VIPP1, IFT46, CrTET1 and CrKU80 genes, and placing a YFP tag into VIPP1 and IFT46 for live-cell imaging. We also successfully performed a single amino acid substitution for the FLA3, FLA10 and FTSY genes, and documented the attainment of the anticipated phenotypes. Lastly, we demonstrated that precise fragment deletion from the 3'-UTR of MAA7 and VIPP1 resulted in a stable knock-down effect. Overall, our study has established efficient methods for multiple types of precise gene editing in Chlamydomonas, enabling substitution, insertion and deletion at the base resolution, thus improving the potential of this alga in both basic research and industrial applications.

Risk factors for diabetic foot ulcers: A systematic review and meta-analysis

OBJECTIVE

To systematically evaluate the risk factors for developing diabetic foot ulcers (DFU).

METHODS

The Cochrane Library, PubMed, Web of Science, SinoMed, CNKI, VIP, and Wanfang Data were searched for relevant studies on DFU risk factors, and the search time frame was from database creation to March 2022. Meta-analysis was performed using RevMan 5.3.

RESULTS

A total of 26 publications were included, including 3 cohort studies, 22 case-control studies, and one cross-sectional study. Meta-analysis showed that advanced age [MD = 6.04, 95% CI (3.92, 8.16)], male [OR = 1.84, 95% CI (1.48, 2.29)], elevated body mass index [MD = 1.58, 95% CI (0.47, 2.69)], prolonged duration of diabetes [MD = 2.72, 95% CI (2.33, 3.11)], comorbid nephropathy [OR = 3.15, 95% CI (2.68, 4.60)], comorbid neuropathy [OR = 4.80, 95% CI (2.79, 8.27)], comorbid retinopathy [OR = 3.37, 95% CI (2.26, 5.02)], elevated systolic blood pressure [OR = 8.19, 95% CI (6.33, 10.05)], elevated fasting glucose [MD = 1.60, 95% CI (0.21, 3.00)], elevated glycated hemoglobin [MD = 1.24, 95% CI (0.94, 1.54)], elevated triglycerides [MD = 0.44 (95% CI (0.15, 0.73)], elevated fibrinogen [MD = 1.35, 95% CI (0.62, 2.08)], elevated white blood cell count [MD = 2.56, 95% CI (2.24, 2.88)], elevated C-reactive protein [MD = 15.08, 95% CI (8.03, 22.13)], decreased ankle-brachial ratio [MD = -0.26, 95% CI (-0.36, -0.16)], and decreased total protein levels [MD = -4.58, 95% CI (-6.91, -2.25)] were risk factors for developing DFU (p < 0.05), and increased HDL cholesterol levels [MD = -0.22, 95% CI (-0.36, -0.08)] were protective factor for developing DFU (p < 0.05).

CONCLUSION

There are many risk factors for developing of ulcers in the diabetic feet, and early prevention and intervention should be performed as early as possible to assess the risk of developing diabetic foot patients.

[Analysis of the effect of spread through air spaces on postoperative recurrence-free survival in patients with stage pT1N0M0 lung adenocarcinoma of different tumor size]

Objective: To investigate the effect of spread through air spaces (STAS) on the postoperative prognosis of patients with stage pT1N0M0 lung adenocarcinoma according to different tumor sizes. Methods: The clinicopathological and follow-up data of 511 patients with pT1N0M0 lung adenocarcinoma treated surgically in the Department of Thoracic Surgery, Cancer Hospital, Chinese Academy of Medical Sciences from January 2014 to June 2018 were retrospectively analyzed. There were 285 males and 226 females, aged 60 (53, 66) years. Those patients were divided into two groups according to STAS status, including STAS (-) group (342 cases) and STAS (+) group (169 cases). And the stratified analysis was performed according to the American Cancer Consortium (AJCC) 8th edition postoperative pathological tumor size T-stage (pT) of lung cancer, which was divided into pT1a (pT≤1 cm, 93 cases), pT1b (1 cm<pT≤2 cm, 280 cases), pT1c group (2 cm<pT≤3 cm, 138 cases) and pT1b/c (1 cm<pT≤3 cm, 418 cases). Univariate and multivariate Cox regression analyses and inverse probability weighted (IPTW) adjusted Kaplan-Meier (K-M) curves were used to analyze the effect of STAS on recurrence-free survival (RFS) in patients included in this study. Results: The recurrence rate was significantly higher in the STAS (+) group compared to the STAS (-) group (22.5% vs 3.2%, P<0.001). Multifactorial Cox regression analysis based on pT stratification showed that the risks of recurrence were 4.56-fold (95%CI:1.56-13.33; P=0.006) and 3.16-fold (95%CI:1.07-9.33; P=0.038) higher in pT1b and pT1c staged patients with STAS (+) than in STAS (-) patients, respectively. There was no significant difference in RFS between the STAS (-) group of pT1b/c, pT1b and pT1c and all pT1a patients [(84.97±0.72) vs (84.05±1.11) months, (85.60±0.74) vs (84.05±1.11) months, (81.49±1.63) vs (84.05±1.11) months; all P>0.05]. Before and after IPTW adjustment, statistically significant differences were found in RFS between STAS (+) group and STAS (-) group [(72.50±2.23) vs (85.12±0.72) months, (77.74±1.12) vs (84.59±0.64) months, all P<0.001]. In addition, the risks of both local and distant recurrence were higher in STAS (+) group compared to STAS (-) group (6.7% vs 1.2% and 8.2% vs 3.6%, respectively; both P<0.05). Conclusion: For lung adenocarcinoma patients with pT1bN0M0 and pT1cN0M0, those patients with STAS (+) had a higher incidence of both local and distant recurrence and with poor RFS.

[New discovery and short-term effect analysis of tensor tympani muscle tenotomy for Meniere's disease under otoscope]

Objective: To explore the feasibility and short-term effect of tensor tympani muscle Tenotomy in the treatment of Meniere's disease under otoscope. The possible pathogenesis was discussed and our views were put forward. Methods: The clinical data of 9 cases of Meniere's disease treated by otoscopic Tenotomy were analyzed retrospectively, including 2 males, 7 females, 5 right ones, 2 left ones and 2 bilateral ones. The average age was (56.33± 10.56) years, ranging from 38 to 75 years. We evaluated intraoperative findings and short-term postoperative efficacy, respectively evaluated postoperative aural fullness, tinnitus and hearing recovery, and evaluated postoperative vertigo attack in a short time. Results: Nine patients were completed the operation under general anaesthesia and otoscopy, and no serious complications occurred. We found new pathological changes in tympanic cavity in some cases during operation. There were rupture of round window membrane in 1 case, severe fibrous hyperplasia near the round window membrane and vestibular window and adhesion with ossicular chain in 1 case, fibrous cord and membranous hyperplasia near vestibular window and round window membrane in 1 case, fibrous hyperplasia and adhesion near the round window membrane in 2 cases, membranous hyperplasia and adhesion around vestibular window in 1 case. No fibrous hyperplasia was found in 3 cases in the tympanic cavity. The round window membrane can be exposed in 4 cases and failed in 5 cases. After 3 months of follow-up, we found that we found that 5/5 cases of aural fullness disappeared, 2/2 cases of earache disappeared, 3/8 cases of tinnitus improved, 5/8 cases presented with improvement and no aggravation, 3/3 cases of hearing allergy improved, 4/9 cases of hearing improved, and 5/9 cases showed no improvement or decrease. 9 patients were followed up for 3 months, of whom 8 patients had no vertigo, one patient suffered from vertigo twice within 3 months after operation, and the patient suffered from rupture of round window membrane. Conclusions: Endoscopic Tenotomy for Meniere's disease has obvious curative effect and quick recovery after operation. During the operation, we find that most of Meniere's patients have fibrous cord hyperplasia near the inner ear window membrane, which may be the pathological manifestation after repeated rupture and repair of the inner ear window membrane. The vertigo of Meniere's disease may be related to the destruction and repair of inner ear membrane structure caused by improper contraction or spasm of tympanic tensor muscle.

Antihypertensive effects of exercise involve reshaping of gut microbiota and improvement of gut-brain axis in spontaneously hypertensive rat

Exercise (Ex) has long been recognized to produce beneficial effects on hypertension (HTN). This coupled with evidence of gut dysbiosis and an impaired gut-brain axis led us to hypothesize that reshaping of gut microbiota and improvement in impaired gut-brain axis would, in part, be associated with beneficial influence of exercise. Male spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) rats were randomized into sedentary, trained, and detrained groups. Trained rats underwent moderate-intensity exercise for 12 weeks, whereas, detrained groups underwent 8 weeks of moderate-intensity exercise followed by 4 weeks of detraining. Fecal microbiota, gut pathology, intestinal inflammation, and permeability, brain microglia and neuroinflammation were analyzed. We observed that exercise training resulted in a persistent decrease in systolic blood pressure in the SHR. This was associated with increase in microbial α diversity, altered β diversity, and enrichment of beneficial bacterial genera. Furthermore, decrease in the number of activated microglia, neuroinflammation in the hypothalamic paraventricular nucleus, improved gut pathology, inflammation, and permeability were also observed in the SHR following exercise. Interestingly, short-term detraining did not abolish these exercise-mediated improvements. Finally, fecal microbiota transplantation from exercised SHR into sedentary SHR resulted in attenuated SBP and an improved gut-brain axis. These observations support our concept that an impaired gut-brain axis is linked to HTN and exercise ameliorates this impairment to induce antihypertensive effects.

[A challenge for colorectal surgeons: pathogenesis, progression and management of the secondary tumors of the ovary]

A common clinical problem encountered by colorectal surgeons is the secondary tumors of the ovary (STO), particularly in young female patients. Most STO are from the digestive tract, and the known possible metastatic mechanisms include lymphatic, hematogenous, and intraperitoneal spreading. The molecular and histopathological characteristics of STO from different sites are diverse. It is particularly important to correctly identify the origin and feature of STO, which should be clarified by combining medical history, histopathology, immunohistochemistry, molecular biology, imaging and other means. The prognosis of patients with STO is poor in general. Comprehensive therapies based on surgical resection can benefit some patients. There is no specific treatment for STO at present, but not giving up easily on these patients is the right choice that every surgeon should understand.

[Comparative analysis on seroprevalence of hepatitis B in Guangzhou in 2008 and 2018]

Objective: To compare the seroprevalence of hepatitis B in Guangzhou in 2008 and 2018. Methods: According to the proportion of Guangzhou population size, two-stage cluster sampling was used to select the residents aged 1-59 years in the two surveys. Results: 4 989 and 3 980 people aged 1-59 years were involved in 2008 and 2018, respectively. HBsAg prevalence was 9.50% (95%CI:7.34%-11.66%) in 2018 and 12.45% (95%CI:10.58%-14.33%) in 2008 among the people aged 1-59 years, with no significant difference statistically (χ²=18.302, P=0.075). The decrease of HBsAg prevalence was mainly in the population aged 7-16 years. For the people aged 7-16 years, the HBsAg prevalence was 0.88% (95%CI: 0.35%-1.42%) in 2018 and decreased by 80.62% as compared with the rate 4.54% (95%CI:2.71%-6.36%) in 2008, with statistically significant difference (χ²=34.144,P=0.000). Anti-HBs prevalence was 72.30% (95%CI:69.56%-75.04%) in 2018 and ascended by 11.35% as compared with the rate of 64.93% (95%CI:61.65 %-68.22%) in 2008 among the people aged 1-59 years, with statistically significant difference (χ²=51.618, P=0.001). The rise of anti-HBs prevalence was mainly in the population aged 17-59 years. For the people aged 17-59 years, the anti-HBs prevalence was 71.93% (95%CI: 68.90%-74.96%) and risen by 12.80% as compared with the rate of 63.77% (95%CI: 60.16%-67.37%) in 2008, with a statistically significant difference (χ²=28.422, P=0.001). HBV infection rate was 48.10% (95%CI: 43.20%-53.00%) in 2018 and decreased by 22.76% as compared with the rate of 62.27% (95%CI: 59.11%-65.44%) in 2008, with statistically significant difference (χ²=167.138, P=0.000). The HBV infection rates in the population aged 1-6 years, 7-16 years, and 17-59 years were 4.58%, 5.13%, and 56.56% (a decrease of 81.83%, 85.91%, and 18.47%), respectively. The infection rate of HBV was 48.87% (a decrease of 24.70%) in high epidemic areas and 28.81% (a decrease of 38.75%) in people with a history of hepatitis B immunization. Conclusion: The prevention and control of hepatitis B in Guangzhou have achieved remarkable results it already reached the national goal of reducing HBsAg prevalence to less than 1% among children under five years since 2008. However, the target goal of reducing the hepatitis B mortality rate is quite demanding. The neonatal hepatitis B vaccination and monitoring and screening in adults are still needed.

Computer-Based 3D Simulations to Formulate Preoperative Planning of Bridge Crane Technique for Thoracic Ossification of the Ligamentum Flavum

Background

The bridge crane technique is a novel surgical technique for the treatment of thoracic ossification of the ligamentum flavum (TOLF), but its preoperative planning has not been studied well, which limits the safety and efficacy of surgery to some extent. The purpose of this study was to investigate the method of application and effect of computer-aided preoperative planning (CAPP) on the bridge crane technique for TOLF.

Material/Methods

This retrospective multi-center included 40 patients with TOLF who underwent the bridge crane technique from 2016 to 2018. According to the utilization of CAPP, patients were divided into Group A (with CAPP, n=21) and Group B (without CAPP, n=19). Comparisons of clinical and radiological outcomes were carried out between the 2 groups.

Results

The patients in Group A had higher post-mJOA scores and IR of neurological function than those in Group B (p<0.05). Group A had shorter surgery time, fewer fluoroscopic images, and lower incidence of complications than Group B. In Group A, there was a high consistency of all the anatomical parameters between preoperative simulation and postoperative CT (p>0.05). In Group B, there were significant differences in 3 anatomical parameters between postoperative simulation and postoperative CT (p<0.05). In Group B, the patients with no complications had higher post-SVOR and lower SVRR and height of posterior suspension of LOC in postoperative CT than those in postoperative simulation (p<0.05).

Conclusions

CAPP can enable surgeons to control the decompression effect accurately and reduce the risk of related complications, which improves the safety and efficacy of surgery.

[Analysis of risk factors for acute lung injury/acute respiratory distress syndrome after esophagectomy]

OBJECTIVE

To explore the incidence and risk factors for the acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) after resection of esophageal carcinoma.

METHODS

We retrospectively analyzed 422 consecutive patients admitted to the Department of Critical Care Medicine with esophageal carcinoma undergoing esophagectomy from January 2010 to December 2016 in Peking University Cancer Hospital. ALI/ARDS were diagnosed, the patients were divided into ALI/ARDS group and control group without ALI/ARDS, the differences of clinical features were contrasted between the two groups, and the multivariate Logistic regression modeling was used to identify the independent risk factors for ALI/ARDS.

RESULTS

In the study, 41 ALI/ARDS cases were diagnosed, making up 9.7% (41/422) of all the enrolled patients undergoing esophagectomy. Comparisons of the ALI/ARDS group and the control group indicated significant statistical differences in the average length of their hospital stay [(18.9±9.7) d vs. (14.8±3.6) d, P=0.011], the proportion of the patients who needed mechanical ventilation support [51.2% (21/41) vs. 9.4% (36/381), P<0.001] and in-hospital mortality [31.7% (13/41) vs. 5.0% (19/381), P<0.001]. Univariate analysis showed significant differences between the patients with ALI/ARDS and without ALI/ARDS in smoking history (P=0.064), preoperative forced expiratory volume in one second/forced vital capacity (FEV1/FVC) (P=0.020), diffusing capacity of the lung for carbon monoxide (DLCO) (P=0.011), body weight index (BMI) (P=0.044), American Society of Anesthesiologists (ASA) physical status classification (P=0.049) and one lung ventilation duration (P=0.008), while multivariate Logistic regression analysis indicated that preoperative FEV1/FVC (OR=1.053, P=0.016, 95%CI 1.010-1.098), ASA physical status classification (OR=2.392, P=0.033, 95%CI 1.073-5.335) and one lung ventilation duration (OR=0.994, P=0.028, 95%CI 0.989-0.999) were the independent risk factors for ALI/ARDS after esophagectomy.

CONCLUSION

ALI/ARDS was a serious complication in patients undergoing esophagectomy associated with increment in length of hospital stay and in-hospital mortality. Multivariate Logistic regression analysis indicated that preoperative FEV1/FVC, ASA classification and one lung ventilation duration were the independent risk factors for ALI/ARDS after esophagectomy. Carefully assessing the patient before operation, shortening one lung ventilation duration were the key points in preventing ALI/ARDS after esophagectomy.

[The study of growth differentiation factor-15 in chronic thromboembolic pulmonary hypertension following acute pulmonary thromboembolism]

Objective: To evaluate the incidence of chronic thromboembolic pulmonary hypertension (CTEPH) secondary to acute pulmonary thromboembolism (PTE) and the serum level of growth differentiation factor-15(GDF-15). Methods: Ninety-six acute PTE patients were recruited in the study. Clinical data, Wells score, blood gas analysis, D-dimmer level, GDF-15 level, atrial and ventricular sizes, pulmonary arterial systolic pressure (PASP) and pulmonary artery CT (CTPA) data were collected. Patients were followed up to evaluate the cardiac function (WHO class), ultrasonic cardiogram and CTPA to confirm the incidence of CTEPH. Results: Eighty-fivepatients were followed for 5 months to 58 months (average 26.5±14.7 months). The incidence of CTEPH was 12.9% (11/85). Between CTEPH patients and non-CTEPH patients, PASP, right atrial and ventricular sizes, and GDF-15in the acute stage were significantly different(P<0.05). According to binary logistic regression analysis, the incidence of CTEPH was correlated positively with acute PASP and the serum level of GDF-15. Conclusions: The incidence of CTEPH in acute PTE patients was 12.9% in this study. Acute PASP and higher level of GDF-15 are predictive factors for CTEPH secondary to acute PTE.

[Pulmonary surfactant protein adenosine triphosphate-binding-cassette-A3 gene composite mutations in infant congenital interstitial lung disease: report of a case and review of literature]

Objective: To report a case of the pulmonary surfactant protein(SP) adenosine triphosphate-binding-cassette-A3 (ABCA3) gene mutations in infant congenital interstitial lung disease(ILD), and review the related literature, to investigate the relationships of ABCA3 gene mutation associated with ILD in infants. Method: A 6-months-old boy was hospitalized in the department of Pediatrics of the First Affiliated Hospital of Guangzhou Medical University. The clinical, radiological, histological information from transbronchial lung biopsy (TBLB) and genetic testing in this case was analyzed; 12 reports retrieved on literature search at Pubmed, OVID databases from 2004 to 2015 by using the ABCA3 as keyword were reviewed and analyzed. Result: (1)The patient, a 6-months-old boy, had progressive tachypnea and dyspnea since 4 months old. Physical examination on admission revealed respiratory rate of 78 times/min , heart rate of 187 times/min, SpO₂ 0.93(mask oxygen-inspiration with 6 L/min), scattered fine moist crackles could be heard over the both lungs, clubbing fingers were found. High-resolution computed tomography(HRCT) revealed diffuse ground-glass opacity, interlobular and intralobular septal thickening. Lung biopsies showed evidences of the alveolar cavity atelectatic changes and interstitial fibrosis. SP-A and SP-B were negative in immunohistochemical stainting. SP-related gene sequence analysis found that there was compound heterozygous missense mutation of ABCA3 gene in c. 1942A>G, c.2701-33G>C and c. 991-105C>A. (2)The review of related literature found that totally 12 cases were reported. The main manifestations were progressive tachypnea and dyspnea, age of onset was between birth and 4 years of age. The imaging characteristics of chest HRCT revealed diffuse infiltration or diffuse ground-glass pattern in the lung.

PROGNOSIS

6 cases died, and 6 cases survived, including 4 cases with pulmonary function disturbance to different degrees; 12 cases had ABCA3 gene mutations, 9 cases had composite ABCA3 gene mutations, in 11 cases the mutation occured in the exon of coding region, in 1 case in the intron, 9 cases had heterozygous mutations, 3 cases had homozygous mutations. Conclusion: The main phenotypes of ABCA3 mutation associated with ILD were full term neonatal respiratory distress syndrome or progressive tachypnea or dyspnea unexplained in infants. The chest HRCT showed two diffuse pulmonary interstitial changes. ABCA3 mutation mainly was multi-site composite mutations and heterozygous mutations in the exon of coding region.

Protection from vascular endothelial dysfunction in acute glycemic load-induced primary hypertension by vitamin C and E

This study aimed to investigate the influence of acute glycemic load on vascular endothelial function in patients with hypertension and to evaluate the protective effect of vitamins C and E during the acute glycemic phase. We randomly selected 39 hypertensive patients and 21 normal subjects and divided them into 3 groups: 75 g oral glucose (glycemic load group), 75 g glucose+0.9 g vitamin C (VC group), 75 g glucose+2 g vitamin C+0.8 g vitamin E (VC+VE group). Extravascular color Doppler ultrasound was used to detect brachial artery flow-mediated vasodilation at 0, 1, 2, and 3 h, and, at the same time, serum anti-oxidant products were measured. Basic endothelial functions in patients with hypertension were decreased in the glycemic load group (9.48±3.33 versus 13.09±6.78%, P<0.05), and was even more depressed in the hypertensive group (9.48±3.33 versus 14.20±6.48%, P<0.05). Antioxidant vitamins played a dose-dependent protective role on acute damage of endothelial function due to glycemic load. Acute high blood sugar damaged vascular endothelial functions, especially in hypertensive patients, but this effect can be reversed by large doses of vitamin C and E.

Regulation of N-acetyl cysteine on gut redox status and major microbiota in weaned piglets

This study was conducted to explore the regulation of N-acetyl cysteine (NAC) on gut redox status and proliferation of selected microbiota in weaned piglets. A total of 150 newborn piglets from 15 litters were randomly divided by litter to the control group (normally suckling), the weaning group (fed the basal diet), and the NAC group (basal + NAC diet) with 5 litters per group. Activities of total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and inhibition capacity of hydroxyl radical (IHR), and contents of malondialdehyde (MDA), H2O2, and NO in the ileum, colon, and cecum were analyzed to profile oxidative stress states. The real-time absolute quantitative PCR reaction was employed to quantify the amounts of total bacteria, Lactobacillus, Bifidobacterium, and Escherichia coli. The N-acetyl cysteine, as a universal antioxidant, was used to improve the redox status. Results showed that weaning stress resulted in the occurrence of gut oxidative stress and changes of gut microbiota (P < 0.05). Compared with the weaned piglets, the activities of ileal, colonic, and cecal T-AOC; ileal and colonic GSH-Px; cecal SOD; and colonic and cecal IHR were enhanced (P < 0.05), and the concentrations of ileal and cecal H2O2, ileal and colonic NO, and colonic MDA were reduced (P < 0.05) in the NAC-treated piglets. An increase (P < 0.05) in gut Lactobacillus and Bifidobacterium, accompanied with a decrease (P < 0.05) in Escherichia coli counts, was also observed in the NAC group. Bivariate correlation indicated that Lactobacillus and Bifidobacterium were positively correlated (P < 0.05) with the activities of T-AOC, GSH-Px, and SOD and inversely related (P < 0.05) to increased levels of H2O2, NO, OH, and MDA, and Escherichia coli showed a strong positive association (P < 0.05) with increased levels of free radicals and MDA and a negative association (P < 0.05) with the activities of antioxidant enzymes in intestines of weaned piglets. We concluded that NAC constructively regulated on the changes of the gut redox status and microbiota in piglets in response to weaning stress. The observed correlations implied that the NAC effects on the gut microbiota were confirmed, partly through an effect on oxidative stress in piglets, providing evidence that gut microbiota may be potentially improved by the modulation of the redox status by an antioxidant, which has relevance for gut health and function.

Gene expression profiling analysis reveals weaning-induced cell cycle arrest and apoptosis in the small intestine of pigs

In swine production, weaning is a critical event for porcine weaning-associated disease, such as postweaning stress syndrome, which involves intestinal dysfunction. However, little is known about the molecular mechanisms of intestinal dysfunction in pigs during weaning. To gain new insight into the interaction between weaning stress and intestinal function, 4 pigs at 25 d of age for each of the weaning and the suckling groups for a total of 40 pigs were used to analyze changes in the genomic expression in the intestines of weaned pigs by microarray analysis. Four hundred forty-five genes showed altered expression after weaning treatment (286 upregulated and 159 downregulated) at the cutoff criteria of the fold change ≥1.5 or <0.67 and P < 0.05. Most of these altered genes are cellular process related and regulators that may be involved in biological regulation, developmental processes, and metabolic processes. A keen interest was paid in deciphering expression changes in apoptosis or cell cycle control genes. The altered genomic expression of 8 selected genes related to the cell cycle process was confirmed by quantitative real-time PCR. Of the 8 genes tested, increased (P < 0.05) expression of genes involved in apoptosis (cytochrome c, somatic, and ataxia telangiectasia mutated), pro-inflammatory signals (tumor necrosis factor and NO synthases 2), and a transcription factor (nuclear factor of activated T cells, cytoplasmic, and calcineurin-dependent 2) were detected in weaned pigs compared with suckling pigs, but the expression of cell cycle control-related genes, such as E2F transcription factor 5-like, was lower (P < 0.05) in weaned pigs than suckling pigs. Weaned pigs also showed increased interleukin 8 expression and decreased SMAD family member 4 expression although no significant differences (P > 0.05) were observed when compared with the suckling pigs. These selected genes likely indicate that weaning induced cell cycle arrest, enhanced apoptosis, and inhibited cell proliferation. The results of this study provide a basis for understanding the molecular pathogenesis of weaning treatment.

Phosphoinositide kinases play key roles in norepinephrine- and angiotensin II-induced increase in phosphatidylinositol 4,5-bisphosphate and modulation of cardiac function

The seemly paradoxical Gq agonist-stimulated phosphoinositide production has long been known, but the underlying mechanism and its physiological significance are not known. In this study, we studied cardiac phosphoinositide levels in both cells and whole animals under the stimulation of norepinephrine (NE), angiotensin II (Ang II), and other physiologically relevant interventions. The results demonstrated that activation of membrane receptors related to NE or Ang II caused an initial increase and a later fall in phosphatidylinositol 4,5-bisphosphate (PIP2) levels in the primary cultured cardiomyocytes from adult rats. The possible mechanism underlying this increase in PIP2 was found to be through an enhanced activity of phosphatidylinositol 4-kinase IIIβ, which was mediated by an up-regulated interaction between phosphatidylinositol 4-kinase IIIβ and PKC; the increased activity of phosphatidylinositol 4-phosphate 5-kinase γ was also involved for NE-induced increase of PIP2. When the systolic functions of the NE/Ang II-treated cells were measured, a maintained or failed contractility was found to be correlated with a rise or fall in corresponding PIP2 levels. In two animal models of cardiac hypertrophy, PIP2 levels were significantly reduced in hypertrophic hearts induced by isoprenaline but not in those induced by swimming exercise. This study describes a novel mechanism for phosphoinositide metabolism and modulation of cardiac function.

Enzymatic formation of a novel cell-adhesive hydrogel based on small peptides with a laterally grafted l-3,4-dihydroxyphenylalanine group

We rationally designed a bioadhesive supramolecular hydrogel by introducing L-3,4-dihydroxylphenylalanine (DOPA) groups while properly integrating the enzymatic reactions and self-assembly processes. The effective presence of the catechol groups successfully promoted the adhesion and proliferation of human fibroblast cells.

Impact of weaning and an antioxidant blend on intestinal barrier function and antioxidant status in pigs

The objective of this experiment was to investigate the influence of weaning stress and an antioxidant blend on gut health and free radical metabolism in postweaning pigs. A total of 96 pigs from 12 litters were randomly divided by litter to 3 groups with 4 litters each. The control group and the weaning group were fed the basal diet, and the antioxidant group was fed the basal diet supplemented with an antioxidant blend. The control group was suckling normally during the experimental period and the other 2 treatments were weaned at 21 d of age. Morphology in different parts of the intestines was used as a measure of intestinal barrier function. Activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and the concentrations of malondialdehyde (MDA), NO, H(2)O(2), and O(2) were measured in serum. Activities of the digestive enzymes, including sucrase, maltase, amylase, lipase, and pepsin, were measured at 24 d of age for all treatments. Gene expressions of free radicals, digestive enzymes, or antioxidant enzymes were selected for quantitative reverse transcription-PCR analyses. Results showed that weaning resulted in reductions (P < 0.05) in the villus height and width, and activity of digestive enzymes. Activity of SOD decreased (P < 0.05) and the concentrations of MDA, NO, and H(2)O(2) increased (P < 0.05) after weaning. The expression results indicated that the genes related to the antioxidant enzymes and digestive enzymes were down regulated (P < 0.05) after weaning. Tumor protein 53, which regulates reactive oxygen-species generation, tended to increase (P < 0.10) in the weaning group. The concentration of PPARγ coactivator-1α (PGC-1α), which plays an important protective role against oxidative stress by regulating the expression of mitochondrial antioxidants, was reduced (P < 0.05) in weaning pigs and increased (P < 0.01) in antioxidant pigs compared with the control pigs. Results indicated that intestinal dysfunction occurred after weaning and there was an inhibition of the antioxidant system. The antioxidant blend has the potential to prevent free radical-induced damage and suppress oxidative stress by modulating the expressions of tumor protein 53 and PGC-1α genes.

Prediction Models for DNA Transcription Termination Based on SOM Networks

This paper presents two efficient models for predicting transcription termination (TT) in human DNA. A neural network, self-organizing map, was used for finding features from a human polyadenylation (polyA) sites dataset. We derived prediction models related to different polyA signals. A program, "Dragon PolyAtt", for predicting TT regions was designed for the two most frequent polyA sites "AAUAAA" and "AUUAAA". In our tests, Dragon PolyAtt predicts TT regions with a sensitivity of 48.4% (13.6%) and specificity of 74% (79.1%) when searching for polyA signal "AAUAAA" ("AUUAAA"). Both tests were done on human chromosome 21. Results of Dragon PolyAtt system are substantially better than those obtained by the well-known "polyadq" program.

Synthesis of 1-(N-ethoxycarbonylamino)alkylphosphonic monoesters

A series of 1-(N-ethoxycarbonylamino)alkylphosphonic monoesters were synthesized via three-component Mannich-type condensation of ethyl carbamate, aldehydes and dichlorophosphites in benzene, followed by hydrolysis.

Periodic speed ripples minimization in PM synchronous motors using repetitive learning variable structure control

In this paper, we propose a simple repetitive learning variable structure control (RLVSC) scheme to reduce periodic speed ripples in a permanent magnet synchronous motor (PMSM). These speed ripples are induced by parasitic torque pulsations that vary periodically with rotor position. The conventional PI speed controller is able to reduce speed ripples to a certain extent but not sufficient enough for many high performance applications. During steady state, the RLVSC generates a reference compensation current that together with the outer loop PI speed controller is used to minimize the speed ripples. Being a plug-in module, the proposed RLVSC controller can be easily integrated to any of the existing PMSM drive systems. Experimental evaluation of the proposed scheme is carried out on a DSP-controlled PMSM drive platform. Test results obtained demonstrate the effectiveness of the proposed control scheme in reducing speed ripples by a factor of approximately 3 under various operating conditions.

[Analysis of isozyme and RAPD for the germplasm lines from G. hirsutum x G. bickii]

To study the effectiveness of Gossypium interspecific hybrid breeding on molecular level, the six germplasm lines from interspecific hybrids between G. hirsutum and G. bickii were analysed by the techniques of RAPD and isozyme electrophoresis. The main results were summarized as follows: (1) The basic zymograms of peroxidase isozyme of the six germplasm lines were similar to their G. hirsutum parent, but two out of the germplasm lines showed one specific band of the wild parent of G. bickii (pI 4.85); (2) The RAPD fingerprint showed distinct difference of genomic DNA among the germplasm lines; (3) The four specific DNA fragments of G. bickii were observed in RAPD patters of four out of the six germplasm lines.

[A study of genetic character of cultivar Shiyuan 321 from G. barbadense x G. thurberi x G. hirsutum using isozyme and RAPD techniques]

To study the genetic character of trispecific hybrid cultivar Shiyuan 321, we analyzed this cultivar and its parents by isozyme and RAPD techniques. The main results are as follows: (1) Esterase isozyme analysis showed that there was one specific band among cultivar Suiyuan 321 and its parents, G. thurberi and G. barbadense; (2) Six specific DNA fragments amplified by 4 primers were found among cultivar Shiyuan 321 and its parents G. barbadense, G. thurberi; (3) By comparing RAPD differences among Shiyuan 321 and its parents, it is indicated that the genetic heterogeneity of cultivar Shiyuan 321 is very high at its genomic DNA level. The above results proved that Shiyuan 321 is a trispecific cultivar from G. barbadense x G. thurberi x G. hirsutum as well as a new germplasm.

Global dynamics and stochastic resonance of the forced FitzHugh-Nagumo neuron model

We have analyzed the responses of an excitable FitzHugh-Nagumo neuron model to a weak periodic signal with and without noise. In contrast to previous studies which have dealt with stochastic resonance in the excitable model when the model with periodic input has only one stable attractor, we have focused our attention on the relationship between the global dynamics of the forced excitable neuron model and stochastic resonance. Our results show that for some parameters the forced FitzHugh-Nagumo neuron model has two attractors: the small-amplitude subthreshold periodic oscillation and the large-amplitude suprathreshold periodic oscillation. Random transitions between these two periodic oscillations are the essential mechanism underlying stochastic resonance in this model. Differences of such stochastic resonance to that in a classical bistable system and the excitable system are discussed. We also report that the state of the basin of attraction has a significant effect on the stability of neuronal firings, in the sense that the fractal basin boundary of the system enhances the noise-induced transitions.

[Introduction of rabbit defensin NP-1 gene into poplar (P. tomentosa) by Agrobacterium-mediated transformation]

Rabbit defensin NP-1 possesses a broad resistant spectrum to pathogens. In this work, we have transferred the NP-1 gene into poplar plants by Agrobacterium-mediated transformation. PCR amplification and Southern analysis showed that rabbit defensin NP-1 gene was integrated into the poplar genome. The transformation efficiency is about 15.6%. Antimicrobial activity test showed that the extract of transgenic plants inhibited the growth of the tested microbes.

User acceptability of a female condom (Reality) in Shanghai

Thirty married couples evaluated the Reality female condom on questionnaires about its acceptability for 300 acts of coitus (10 per couple). An analysis of the summary questionnaires showed: 90% of couples considered the female condom an acceptable method and 87% felt it was a good contraceptive device; the majority of couples (87%) found it easy to use; and 80% of females and 73% of males reported that, in comparison with the male condom, the effect on sexual pleasure was either improved or no different. A little more than half of the couples (55%) preferred it to male condoms. To look at the learning curve effect, an additional analysis was completed by pooling the first 5 applications of each user and comparing the results with the pooled results of the second 5 uses. All the findings suggest that a certain proportion of couples of childbearing age will choose the Reality female condom for contraception if it enters into the Chinese market. As a new contraceptive barrier device, the female condom may require a certain amount of education and awareness before it will be fully recognized as an important option to help prevent pregnancy as well as sexually transmitted infections.

Inactivation of succinate-ubiquinone reductase in substrate mixture

Succinate-ubiquinone reductase plays an important role in the respiratory chain. Previous work showed that preparation of succinate-ubiquinone reductase was relatively stable. Though the enzyme catalysis has been extensively studied, the inactivation of succinate-ubiquinone reductase has never been reported. In the present study, the kinetic theory of the substrate reaction of irreversible inhibition described by Tsou (Adv. Enzymol. Relat. Areas Mol. Biol. 61 (1988) 381-436) was applied to study the course of an unexpected slow inactivation of succinate-ubiquinone reductase in the substrate assay mixture containing different concentrations of substrates, succinate and 2,6-dichloroindophenol. The results showed that the inactivation of succinate-ubiquinone reductase in the substrate mixture is a first order reaction. The inactivation rate decreased with increasing concentration of succinate. The values of the micro rate constants for free and succinate bound enzyme were 0.22 +/- 0.01 and 0.052 +/- 0.002 min-1, respectively. Binding with 2-thenoyl-trifluroacetone, a inhibitor specially for the quinone binding site, slowed down the inactivation. However, the rate of inactivation did not change with increasing 2,6-dichloroindophenol concentration. The study showed that succinate-ubiquinone reductase was irreversibly inactivated in the substrate mixture. The results suggest that the inactivation was not due to dilution or dissociation of the enzyme, nor to complete usage of the substrate, inhibition of the yielded product or some possible trace component in the substrate mixture, nor to modification of the essential thiol group in the succinate binding site of succinate-ubiquinone reductase. The enzyme became more stable after binding with succinate.

A comparative study of two techniques used in immediate postplacental insertion (IPPI) of the Copper T-380A IUD in Shanghai, People's Republic of China

Chinese women in Shanghai who delivered vaginally and who chose to use an IUD for contraception received a Copper T-380A IUD inserted vaginally within 10 minutes after delivery of the placenta (i.e., immediate postplacental insertion, IPPI). Among them, 97.7% were primipara. The women were randomly divided into two groups: IUD inserted by hand and IUD via ring forceps. The follow-up rate of six months was 95.2%. Using Tietze's life table method and log rank test, the expulsion and other discontinuation rates were compared at three and six months postinsertion between these two different insertion techniques. Expulsions were the main reason for discontinuation. The six-month gross cumulative expulsion rates were 13.3 and 12.7 per 100 women in the hand-insertion group and ring forceps-insertion group, respectively. Discontinuation rates for medical removals (bleeding/pain) were 2.1 and 1.0 in these two groups, respectively. Neither of the differences was statistically significant (p > 0.05). No uterine perforation, infection or pregnancy occurred. The results suggest that these two different insertion techniques do not significantly affect discontinuation rates in vaginal IPPI using the TCu 380A, and the TCu 380A appears to be suitable for postpartum insertion in Chinese women. Other relevant issues, such as breastfeeding and IUD placement in uterine cavity, are also analyzed and discussed in this report.

Kinetics of modification of the mitochondrial succinate-ubiquinone reductase by 5,5'-dithiobis-(2-nitro-benzoic acid)

The kinetic theory of the substrate reaction during modification of enzyme activity previously described by Tsou [Tsou (1988), Adv. Enzymol. Relat. Areas Mol. Biol. 61, 381-436] has been applied to a study of the kinetics of the course of inactivation of the mitochondrial succinate-ubiquinone reductase by 5,5'-dithiobis-(2-nitro-benzoic acid) (DTNB). The results show that the inactivation of this enzyme by DTNB is a conformation-change-type inhibition which involves a conformational change of the enzyme before inactivation. The microscopic rate constants were determined for the reaction of the inactivator with the enzyme. The presence of the substrate provides marked protection of this enzyme against inactivation by DTNB. The modification reaction of the enzyme using DTNB was shown to follow a triphasic course by following the absorption at 412 nm. Among these reactive thiol groups, the fast-reaction thiol group is essential for the enzyme activity. The results suggest that the essential thiol group is situated at the succinate-binding site of the mitochondrial succinate-ubiquinone reductase.

Billings natural family planning in Shanghai, China

With cervical mucus, or Billings, method of family planning, a woman learns to recognize the characteristics of her cervical mucus that identify the fertile phase in her menstrual cycle. She and her partner abstain from sexual activity during a period from the first indication of mucus until four days after the mucus peak day, which includes ovulation. They also abstain during menses, because mucus can be confused with menstrual bleeding. This method of family planning is used widely, worldwide, by couples seeking a natural, reliable method of family planning. Between July 1988 and May 1990, 688 couples of child-bearing age, most of whom were parous, used the Billings method for contraception. Five hundred and fifty of these couples used the method for more than 12 months. Efficacy, continuation rates, and discontinuation rates were analyzed using life-table analysis for 10,175 woman-months of data collected. The net cumulative discontinuation rates per 100 women at 12 and 18 months were 19.85 and 34.58, respectively, resulting in continuation rates of 80.15 and 65.42. The discontinuation rates per 100 women for method-related reasons at 12 and 18 months were 1.61 and 2.84, respectively, while the discontinuation rates for unintended pregnancy were 1.02 and 1.18. During the study, 67 subjects volunteered to have vaginal smears taken from the upper part of the vaginal wall for cytologic examinations, and among them serum and urine LH levels were measured in 10 subjects and urinary estrogen and progesterone were assayed in 35 cases. These tests related other indications of the menstrual cycle to the ability of the women to judge ovulation by cervical mucus. Our research suggests that further investigation of the Billings method is warranted and that careful planning and organization are needed to disseminate the method more broadly.

Immediate postplacental insertion of the intrauterine device: a review of Chinese and the world's experiences

The postpartum period is an ideal time to begin contraception, as women are more highly motivated to adopt contraception at this time and it is convenient for both patients and service providers. For intrauterine device (IUD) contraception, this period offers other advantages, such as ease of insertion and minimal adverse impacts on breastfeeding. Among early studies, most postpartum insertions were performed anywhere from a few hours to seven days or more after delivery, and retention of the IUD in the uterus was poor. Since the 1970s, immediate postplacental insertion (IPPI), i.e., IUD insertion performed within 10 minutes after placental delivery, has been advocated, and fairly, low expulsion rates have been reported. Up to now, IPPI has not been widely accepted in clinics because its expulsion rate still appears to be higher than that of interval insertion. In order to further study IPPI and perfect this contraceptive technique, it is essential to comprehensively review IPPI results and compare the Chinese experience with that of the rest of the world.

Comparison between the properties of 3-nitrosalicyl-N-alkylamide and antimycin A acting on QH2:cytochrome c reductase

3-Nitrosalicyl N-alkylamide was found to be an inhibitor different from antimycin A not only in its inhibitory nature but also in many other aspects. This difference indicated that the 11 kDa component, which was identified as the antimycin A (AA) binding factor in the QH2: cytochrome c reductase of Rhodopseudomonas sphaeroides by Wilson et al. ((1985) J. Biol. Chem. 260, 10288-10292) using the radioactive photoaffinity analogue 3-azidosalicyl N-octadecylamide, was not the genuine binding site of AA. Based on the observations that the 3-azidosalicyl N-alkylamide specifically inhibits the reactions of ubiquinone catalyzed by Q-related enzymes of the respiratory chain, the labeled 11 kDa factor might be one of the ubiquinone binding proteins in QH2:cytochrome c reductase.

Immediate postpartum intrauterine device insertion--a report on the Chinese experience

Immediate postplacental insertion (IPPI) of the intrauterine device (IUD) has been practiced in China for at least 17 years. This presentation reviews and integrates the clinical experiences of IPPIs at five Chinese centers. The stainless-steel ring IUD was the most commonly used device for this procedure. Our review indicates that: (a) IPPIs-both after vaginal delivery and at cesarean section-are medically safe and effective in preventing accidental pregnancies (given careful patient selection), and (b) the one-year life-table expulsion rates of IUDs inserted at cesarean section are lower than the rates for vaginal insertions after normal delivery. This review also discusses other issues, such as factors influencing expulsion rates. Generally, IPPIs, whether performed via vagina or cesarean section, seem to be a method of choice for postpartum contraception. Some findings are, however, tentative; thus, further studies are needed.

Two-site property of thenoyltrifluoroacetone inhibiting succinate-ubiquinone reductase

It is proved by using the Dixon plot and the Lineweaver-Burk plot that thenoyltrifluoroacetone (TTFA) has two inhibitive sites affecting the reduction of ubiquinone catalyzed by succinate-ubiquinone reductase. The high affinity site (inhibited at the concentration of thenoyltrifluoroacetone less than 20 mumol/L) shows noncompetitive with substrate Q2, while the low affinity site (inhibited at the concentration of TTFA over 20 mumol/L) shows competitive. It is suggested that both the reducing steps of Q----QH-. and QH-.----QH2 are inhibited by thenoyltrifluoroacetone.

A serologically confirmed, case-control study, of a large outbreak of hepatitis A in China, associated with consumption of clams

A matched and serologically confirmed case-control study was carried out to investigate the source of an outbreak of acute hepatitis involving 290,000 cases in the suburbs of Shanghai, in January 1988. A total of 132 patients with acute hepatitis from six different hospitals were chosen as cases and the same number of control patients without hepatitis were matched for gender, age, admission date and area of residence. Serum specimens from both case and control patients were detected for specific anti-hepatitis A (HA) IgM antibody and a questionnaire was used to investigate probable risk factors related to the outbreak. The positive rate of anti-HA IgM was 98.48% in the case group and only 0.76% in the control, indicating that the infection was caused by HA virus. The results revealed that the source and mode of transmission were due to the consumption of contaminated and inadequately cooked clams (Anadara subcrenata lischke). There was a highly positive dose-response relationship between the odds ratio of contracting HA and the quantity or frequency of clam consumption. The odds ratios of acquiring HA from clams were up to 62.4-63.4 by both group stratification and multiple unconditional logistic regression analyses.