Incidence of brain injuries in premature infants with gestational age ≤ 34 weeks in ten urban hospitals in China.

BACKGROUND: There is a large number (1.5 million per year) of premature births in China. It is necessary to obtain the authentic incidences of intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL), the common brain injuries, in Chinese premature infants. The present multicenter study aimed to investigate the incidence of brain injuries in premature infants in ten urban hospitals in China. METHODS: The research proposal was designed by the Subspecialty Group of Neonatology of Pediatric Society of the Chinese Medical Association. Ten large-scale urban hospitals voluntarily joined the multicenter investigation. All premature infants with a gestational age ≤ 34 weeks in the ten hospitals were subjected to routine cranial ultrasound within three days after birth, and then to repeated ultrasound every 3-7 days till their discharge from the hospital from January 2005 to August 2006. A uniform data collection sheet was designed to record cases of brain injuries. RESULTS: The incidences of overall IVH and severe IVH were 19.7% (305/1551) and 4.6% (72/1551), respectively with 18.4% (56/305) for grade 1, 58.0% (177/305) for grade 2, 17.7% (54/305) for grade 3 and 5.9% (18/305) for grade 4 in nine hospitals. The incidences of overall PVL and cystic PVL were 5.0% (89/1792) and 0.8% (14/1792) respectively, with 84.3% (75/89) for grade 1, 13.5% (12/89) for grade 2, and 2.2% (2/89) for grade 3 in the ten hospitals. The statistically significant risk factors that might aggravate the severity of IVH were vaginal delivery (OR=1.883, 95% CI: 1.099-3.228, P=0.020) and mechanical ventilation (OR=4.150, 95% CI: 2.384-7.223, P=0.000). The risk factors that might result in the development of cystic PVL was vaginal delivery (OR=21.094, 95% CI: 2.650-167.895, P=0.000). CONCLUSIONS: The investigative report can basically reflect the incidence of brain injuries in premature infants in major big cities of China. Since more than 60% of the Chinese population live in the rural areas of China, it is expected to undertake a further multicenter investigation covering the rural areas in the future.

Epidemiological survey on newborns born at the obstetric departments in hospitals in mid-southern region of China in 2005.

OBJECTIVE: To investigate the situations at birth of newborns in the mid-southern region of China by performing a survey on the newborns born at urban hospitals. METHODS: A total of 23 hospitals in the mid-southern region of China were selected to participate in this survey. The data of 15,582 newborns who were born at the obstetric departments from January 1, 2005 to December 31, 2005 were retrospectively investigated. RESULTS: The male to female ratio among newborns was 1.16:1. The incidence of preterm birth was 8.11%, while very low birth weight (VLBW) infants accounted for 0.73%. The rates of spontaneous vaginal delivery and cesarean section ware 57.52% and 40.82%, respectively, while the other delivery modes accounted for 1.66%. The incidence of neonatal asphyxia was 3.78% (0.75% for heavy asphyxia). The mortality of newborns was 0.55% (5.56% for preterm infants). CONCLUSIONS: The incidences of preterm birth and neonatal asphyxia are relatively high in the mid-southern region of China. The rate of cesarean section is abnormally high, which is due mainly to social factors.

[A survey of neonatal births in maternity departments in urban China in 2005].

OBJECTIVE: To study the epidemiology of births in urban China. METHODS: A retrospective study was conducted on neonates born in 2005 in the maternity departments of 72 urban hospitals from 22 provinces in China. RESULTS: A total of 45722 infants born between January 1, 2005 and December 31, 2005 were enrolled. The male to female sex ratio was 1.13:1. Preterm births accounted for 8.1%. The incidence of very low birth weight infants was 0.7%. A total of 99.7% of mothers delivering at term had conceived naturally and 0.3% had experienced assisted reproduction. A total of 98.4% of mothers who delivered preterm had conceived naturally and 1.6% had experienced assisted reproduction. The proportion of vaginal deliveries was 50.8% compared to 49.2% delivered by cesarean sections. Many cesarean sections (38.1%) were due to social factors. Infants with an Apgar score≤7 at 1 minute accounted for 4.8%, and 1.6% of infants had an Apgar score≤7 at 5 minutes. Of all the infants included in the study, 7.14% were admitted to neonatal units for treatment. The death rate of all included infants was 0.74%. CONCLUSIONS: The proportion of preterm births was higher in 2005 than in 2002-2003. The proportion of cesarean section deliveries was much higher in urban China than in most other Asian countries and America.

Epidemiologic survey on hospitalized neonates in China.

OBJECTIVE: To carry out a nationwide epidemiologic survey on the neonates in urban hospitals with an attempt to understand the disease spectrum and treatment outcomes of hospitalized neonates in China. METHODS: The clinical data of 43,289 hospitalized neonates from 86 hospitals in 47 Chinese cities (22 provinces) between January 1, 2005 and December 31, 2005 were retrospectively analyzed. RESULTS: The male:female ratio was 1.73:1. Premature infants accounted for 26.2% of the hospitalized neonates, which was higher than that reported in 2002 (19.7%). The top three diseases during the neonatal period were jaundice, pneumonia, and hypoxic-ischemic encephalopathy. The incidences of pneumonia, meconium aspiration syndrome, and bilirubin encephalopathy in term infants were higher than those in premature infants, while the incidences of asphyxia, respiratory distress syndrome, and pulmonary hemorrhage in term infants were lower than those in premature infants. The incidences of asphyxia, small for gestational age infant, and wet lung were higher in neonates whose mother had pregnancy induced hypertension. The outcomes of these hospitalized neonates included: recovered, 63.9%; improved, 27.3%; discharged due to the family's own decisions, 7.6%, and died, 1.2%. Nearly half (46.4%) of the neonatal death occurred within 24 hrs after admission. CONCLUSION: The incidence of premature birth shows an increasing trend among hospitalized neonates. Since the neonatal deaths mainly occur within 24 hrs after admission, monitoring during this period should be enhanced.

[Measurement of umbilical activin A level in preterm infants].

OBJECTIVE: To evaluate the clinical significance of umbilical activin A in preterm infants. METHODS: Forty-one preterm infants (gestation 28 to 36 weeks) were enrolled. Fetal membranes, umbilical cords and blood samples from umbilical vein were obtained. Umbilical activin A level was measured using ELISA. The histological examinations of fetal membranes and umbilical cords were performed. RESULTS: The umbilical level of activin A averaged 2069 pg/mL in the 41 preterm infants. The umbilical activin A level in the 5 infants with intrauterine infection was higher than in those without intrauterine infection (2510 pg/mL vs 1975 pg/mL; P<0.01). Umbilical activin A level at cutoff of 2490 pg/mL showed a sensitivity of 80.0% and a specificity of 90.6% as a marker of intrauterine infection. There were no significant differences in the umbilical activin A level between the infants with and without respiratory distress syndrome. Umbilical activin A level was positively correlated with the duration of postnatal oxygen therapy (r=0.326, P<0.05). CONCLUSIONS: Umbilical activin A may serve a marker of intrauterine infection in preterm infants. The umbilical activin A level is correlated with the duration of postnatal oxygen therapy.

[An epidemiologic investigation of newborns from obstetric departments in the central south region of China].

OBJECTIVE: To investigate the birth information of newborn infants from obstetric departments in the Central South Region of China. METHODS: A retrospective investigation was carried out in 15582 newborns from obstetric departments of 23 hospitals in the Central South Region of China between January 1 and December 31 of 2005. RESULTS: The sex ratio (male/female) of neonates was 1.16∶1. The proportion of preterm infants was 8.11%. The very low birth weight infants accounted for 0.73%. The neonates born by spontaneous labor accounted for 57.52%. Cesarean sections accounted for 40.82% (social factor of cesarean section: 29.91%). The incidence of neonatal asphyxia was 3.78%, in which 0.75% of the cases were severe asphyxia. The mortality of newborn infants was 0.55%, in which the mortality of preterm infants was 5.56%. CONCLUSIONS: The proportion of preterm infants and the incidence of neonatal asphyxia is high in the Central South Region of China. The proportion of births delivered by cesarean section is high, and social factors are probably responsible for the high rate.

[Multicenter investigation for incidence of periventricular leukomalacia in premature infants in China].

OBJECTIVE: Sponsored by the Subspecialty Group of Neonatology of Pediatric Society, China Medical Association, more than 10 large-scale hospitals participated in the near two-year multicenter investigation for brain injuries in premature infants in China. This study presented the investigation result for the incidence of periventricular leukomalacia (PVL) in premature infants from 10 Third Class A Level hospitals. METHODS: The premature infants with a gestation age<37 weeks in the 10 hospitals were given routine cranial ultrasound scanning within seven days after birth, and then repeated every 3-7 days until discharge from January 2005 to August 2006. The severity of PVL was graded based on de Vries classification. RESULTS: A total of 4 933 premature infants were enrolled. The total incidence of PVL and the incidence of cystic PVL were 2.3% (112/4 933) and 0.3% (16/4 933), respectively. Of the 112 PVL cases, 96 (85.7%) were with grade I, 14 (12.5%) with grade II, and 2 (1.8%) with grade III. The incidence of PVL in 4 maternal and child health care hospitals were significantly lower than that in 6 general or children's hospitals (1.4% vs 2.8%) (X2=10.284, P<0.01). Vaginal delivery and mechanical ventilation were possible high-risk factors for the development of cystic PVL. CONCLUSIONS: The data of the multicenter investigation can basically reflect the situation about the occurrence of PVL in premature infants in major big cities of China. It is important to improve the ability to recognize the sonogram of non-cystic periventricular white matter injury.

[Relationship between alveolar epithelial type II cells and pulmonary surfactant protein A levels in young rats with acute lung injury].

OBJECTIVE: This study examined the relationship between the ultrastructural alterations of alveolar epithelial cells type II (AEC-II) and pulmonary surfactant protein A (SP-A) levels in the lung tissue of young rats with acute lung injury (ALI) in order to explore the possible mechanism of ALI. METHODS: Forty-eight young Sprague-Dawley rats were randomly divided into control and ALI groups. The rats in the ALI group were intraperitoneally injected with 4 mg/kg of lipopolysaccharide (LPS) in order to induce ALI. The control subjects were injected with the same volume of normal saline. Rats were sacrificed at 24, 48 and 72 hrs after LPS or NS injection. Lung samples were obtained from the lower parts of the left lung and fixed with 2.5% glutaraldehyde for transmission electron microscope examination and for Western blot test of SP-A. RESULTS: The microvilli of AEC-II disappeared 24 hrs after LPS injection. After 24 and 48 hrs of LPS injection, lamellar body (Lb) increased in number, enlarged in size and reduced in density, and the ring-like arrangement of Lb was present. By 48 hrs after LPS injection, giant Lb with vacuole-like deformity appeared. The contents of lung SP-A in the ALI group 24 hrs (6.52+/-0.62 vs 5.02+/-0.35; P<0.01) and 48 hrs (6.65+/-0.62 vs 5.01+/-0.36; P<0.01) after LPS injection were significantly higher than those in the control group. By 72 hrs after LPS injection, Lbs ruptured and were reduced in number. The shape of the nuclei was irregular and the border was blurred. The content of lung SP-A was greatly reduced in the ALI group 72 hrs after LPS injection compared with that in the control group (3.87+/-0.50 vs 5.22+/-0.36; P<0.01). CONCLUSIONS: The alterations of AEC-II and lung SP-A were time-dependent in young rats with ALI induced by LPS. In the early stage of ALI, the lung SP-A content showed a compensatory increase. With the increasing injury of AEC-II cells, the secretion of SP-A presented with a decompensation and the lung SP-A content decreased. This may be one possible mechanism for the development of ARD.

[Genetic polymorphism of surfactant protein A in neonatal respiratory distress syndrome].

OBJECTIVE: To investigate the characteristics of gene expression of surfactant protein A in Chinese premature infants and the association between surfactant protein A and the risk of neonatal respiratory distress syndrome (RDS). METHODS: Vein-blood samples (2 mL) from 18 Chinese premature infants with RDS and 28 controls were assayed for SP-A genotypes 6A2, 6A3, 1A0 and 1A1 by SSCP. RESULTS: The frequency of allele distribution of SP-A1 allele 6A2 and 6A3 was 0.50 and 0.056 respectively in the RDS group and was 0.214 and 0.107 in the control group. Compared with the controls, SP-A1 allele 6A2 was over-represented in the RDS group (P<0.05). In contrast, SP-A1 allele 6A3 tended to be under-represented in the RDS group but there was no statistical difference when compared with the controls. The frequency of allele distribution of SP-A2 allele 1A0 and 1A1 was 0.722 and 0.667 respectively in the RDS group and was 0.679 and 0.821 respectively in the control group. There were no significant differences in the distribution frequency of SP-A2 allele 1A0 and 1A1 between the two groups. In the infants born at gestation >32 weeks, SP-A1 allele 6A2 was over-represented in the RDS group compared with the control group (frequency: 0.56 vs 0.15; P<0.05). CONCLUSIONS: The frequency of SP-A1 allele 6A2 and 6A3 was low, in contrast, the frequency of SP-A2 allele 1A0 and 1A1 was high in normal Chinese premature infants. SP-A1 allele 6A2 may be a susceptible gene for RDS.

[Changes of pulmonary surfactant protein A in young rats with acute lung injury induced by lipopolysaccharide].

OBJECTIVE: Pulmonary surfactant protein A (SP-A) plays an important role in the maintenance of pulmonary surfactant function and innative immune defence. This study aimed to explore the changes of SP-A concentration in the lungs of young rats with acute lung injury. METHODS: Sprague-Dawley rats were randomly assigned to control and lung injury groups. Acute lung injury was induced by intraperitoneal injection of lipopolysaccharide (LPS) (4 mg/kg) in the lung injury group. The same amount of normal saline was given for the control group. The two groups were subdivided into 6 groups sacrificed at 6, 12, 24, 36, 48 and 72 hrs of injection (n=8 each). Western blot was employed to detect SP-A concentration in the lung tissues. RESULTS: SP-A concentration in the lung injury group was not different from the the control group within 12 hrs after LPS injection. SP-A concentration in the lung injury group was elevated significantly during 24-48 hrs after LPS injection, peaking at 36 hrs (6.94+/-0.80 vs 5.01+/-0.36; P< 0.01), compared with the controls. However, SP-A concentration in the lung injury group was significantly reduced 72 hrs after LPS injection compared with the controls (P< 0.01). CONCLUSIONS: The changes of lung SP-A concentration in rats following acute lung injury were time-dependent. The transient elevation of SP-A concentration in the lungs indicated a strong compensation ability of SP-A in the host defence against acute lung injury.

Effects of dexamethasone on the ultrastructure of alveolar type II cells in young rats with lipopolysaccharide-induced acute lung injury.

OBJECTIVE: Alveolar type II (AT II) cells play a crucial role in the maintenance of pulmonary surfactant homeostasis and pulmonary immunity. The effects of dexamethasone (Dex) on the ultrastructure of AT II cells after acute lung injury remain unknown. This study focused on the ultrastructural changes caused by acute lung injury and on the effects of Dex administration on these ultrastructural changes in young rats. METHODS: Seventy-two 21-day-old Sprague-Dawley rats were randomly divided into control, acute lung injury and Dex-treated groups. Rats in the lung injury group were intraperitoneally injected with 4 mg/kg lipopolysaccharide (LPS) in order to induce acute lung injury, while the control rats were injected with the same amount of normal saline (NS). The Dex-treated group was injected first with LPS followed 1 hr later by Dex (5 mg/kg) injection. Eight rats in each group were sacrificed 24, 48 and 72 hrs after LPS or NS injection. Lung samples were obtained from the lower parts of left lungs and fixed with 2.5% glutaraldehyde for transmission electron microscope examination. RESULTS: Microvilli of AT II cells disappeared and the number of lamellar bodies (LBs) increased in the lung injury group 24 hrs after LPS injection. The ring-like arrangement of LBs around nuclei was present until 48 hrs after LPS injection. By 48 hrs after LPS injection, giant LBs with vacuole-like abnormalities appeared. The shape of nuclei became irregular and the border of the nuclei became blurred. By 72 hrs after LPS injection, the number of LBs was obviously reduced; nucleoli disappeared; and karyolysis occurred in some of the nuclei. In contrast, in the Dex-treated group, LBs crowded on one side of AT II cells and exocytosis appeared on the same side by 24 hrs after LPS injection. By 48 hrs, the number of LBs was reduced. The number of mitochondria increased, and some of them became swollen and enlarged. However, by 72 hrs, the number of LBs increased and the ring-like arrangement of LBs around the nucleus again appeared. CONCLUSIONS: Ultrastructural changes of AT II cells following lung injury induced by LPS were time-dependent in young rats. Dex may ameliorate AT II cell injury and promote functional restoration of AT II cells in LPS-induced acute lung injury.

Effect of dexamethasone on the content of pulmonary surfactant protein D in young rats with acute lung injury induced by lipopolysaccharide.

OBJECTIVE: Pulmonary surfactant protein-D (SP-D) is regarded as a valuable biomarker in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). This study was to explore the changes of SP-D content in lung tissue following ALI and the effect of dexamethasone (Dex) on the SP-D content in young rats. METHODS: One hundred and forty-four 21-day-old Sprague-Dawley rats were randomly assigned into control, ALI and Dex-treated groups. ALI was induced by intraperitoneal injection of lipopolysaccharide (LPS) (4 mg/kg) in the rats from the ALI and Dex-treated groups. Normal saline was given for the control group. Dex (5 mg/kg) was administered 1 hr after LPS injection in the Dex-treated group. At each time interval of 6, 12, 24, 36, 48 and 72 hrs after LPS injection, eight rats of each group were randomly chosen and sacrificed. Western blot was employed to detect the content of SP-D in lung tissues. RESULTS: The pulmonary SP-D content decreased significantly at 36, 48 and 72 hrs after LPS administration in the ALI group, and reduced to a nadir (0.92 +/-0.11 vs 3.27 +/- 0.52) at 48 hrs compared with that of the control group (P < 0.01). The SP-D content in the Dex-treated group increased significantly at 36,48 and 72 hrs after LPS administration when compared with the ALI group (P < 0.01). A significant difference in the SP-D content between the Dex-treated and the control group was noted only at 72 hrs after LPS administration (P < 0.05). CONCLUSIONS: The SP-D content in lung tissue was reduced following ALI in young rats at the early stage. Early administration of Dex can significantly increase the pulmonary SP-D content.

[Differential response of developing human fetal lung explants to hyperoxia and the effects of dexamethasone on hyperoxia-exposed lungs].

OBJECTIVE: This study aimed to explore the effects of hyperoxia on the development of fetal lung by investigating the changes of morphological and cell proliferation induced by hyperoxia in cultured fetal lungs as well as the effects of dexamethasone on hyperoxia-exposed lungs. METHODS: Human fetal lung explants at the pseudoglandular stage of development were cultured randomly either in normoxia (21% O2/5% CO2) or hyperoxia (95% O2/5% CO2) for 72 hrs. Dexamethasone was added into the feeding medium at the concentration of 10(-6)M. Harvested tissues were stained for pancytokeratin to identify epithelial cells, with Ki-67 as a marker of proliferation. The effects of lung morphometry were analyzed using computer assisted image analysis. The mean airway thickness, the proportion of the surface area occupied by airways, the mean airway surface area and the index of the epithelium proliferation were measured. RESULTS: The lung architectures remained unchanged after 72 hrs normoxia culture, whereas hyperoxia culture resulted in significant dilation of airways and thinning of epithelium, with the surface area of airways of 6662 microm(2) vs 2728 microm(2) and the thickness of airways of 7.8 microm vs 8.1 microm (P < 0.05). Hyperoxia culture also resulted in an increase in the proportion of the surface area occupied by airways than normoxia culture (35.2% vs 23.4%; P < 0.05). The surface area of airways (3174 microm(2)) and the proportion of the surface area occupied by airways (23.9%) decreased significantly in hyperoxia-cultured lungs after dexamethasone administration (P < 0.05). The epithelium proliferation index in hyperoxia-cultured lungs (21.8%) was higher than that in normoxia-cultured lungs (5.1%) and dexamethasone-treated hyperoxia-cultured lungs (7.4%) (P < 0.05). CONCLUSIONS: The exposure of pseudoglandular lungs to hyperoxia modulates the lung architecture to resemble saccular lungs with higher epithelium proliferation index. Dexamethasone may inhibit the effects induced by hyperoxia.

[Kinetics of protein kinase C activities in kidney of fetal rat after intrauterine distress].

OBJECTIVE: The aim of this study is to observe the kinetic changes of protein kinase C (PKC) activities in kidney of fetal rat after intrauterine distress (IUD), and to investigate the roles of PKC in the pathogenesis of kidney impair in IUD of fetal rat. METHODS: SD rats pregnant for 21 days were anesthetized intraabdominally, then one side of vessels of the two horns of uterus were occluded by arterial clamp to make models of intrauterine ischemia, hypoxia (IH) and reperfusion of fetal rat. The fetal rats were divided into IH group (ischemic and hypoxic for 15 min and 30 min, 16 fetal rats for each time point), reperfusion group (ischemic and hypoxic for 30 min, then reperfused for 15 min, 30 min, 45 min, 1 h and 2 h, respectively. 16 fetal rats for each time point) and false operation group (FOG) (18 fetal rats unclamped in the other uterus horn). The kidney tissue was homogenized first, then cell membrane protein and cytoplasmic protein were extracted. Improved Takai method was used to detect the changes of PKC activities of cell membrane and cytoplasma in kidney tissue of fetal rats. RESULTS: (1) PKC activity of cell membrane started to increase after ischemia. The PKC activity of IH group was (5.66 +/- 0.88) pmol.mg(-1).min(-1); FOG was (4.30 + 0.97) pmol.mg(-1).min(-1). The PKC activity of IH group was significantly higher than that of FOG (P < 0.01). PKC activity of cell membrane increased rapidly after reperfusion, reached a peak at 30 min, and then decreased. The PKC activity was (7.26 +/- 0.76) pmol.mg(-1).min(-1) at 15 min, (9.25 +/- 0.94) pmol.mg(-1).min(-1) at 30 min, (8.34 +/- 0.89) pmol.mg(-1).min(-1) at 45 min, (6.57 +/- 0.96) pmol.mg(-1).min(-1) at 1 h, respectively. The PKC activity of reperfusion group was significantly higher than those of FOG (P < 0.01). The PKC activity of reperfusion group was (4.64 +/- 0.96) pmol.mg(-1).min(-1) at 2 h. There was no significant difference compared with that of FOG (P > 0.05). (2) The cytoplasmic PKC activity changed in a tendency opposite to that of the cell membrane PKC activity. In IH group, the PKC activity was (9.74 +/- 1.25) pmol.mg(-1).min(-1) at 15 min, (8.47 +/- 0.84) pmol.mg(-1).min(-1) at 30 min. FOG group was (10.63 +/- 1.92) pmol.mg(-1).min(-1). Reperfusion group reached the lowest PKC activity when reperfused for 30 min, (6.60 +/- 0.94) pmol.mg(-).min(-1), with a significant difference compared with that of FOG (P < 0.01). Then the PKC activity recovered to the level of FOG when reperfused for 2 h, (9.86 +/- 1.00) pmol.mg(-1).min(-1). CONCLUSIONS: After intrauterine ischemia, hypoxia and reperfusion, PKC moves rapidly from cytoplasm to cell membrane in kidney tissue of fetal rat. PKC may be an important intracellular second messenger. It may play an important role in kidney impair in perinatal period.

[Change of neurokinin A plasma level in asthmatic children].

OBJECTIVE: Chronic inflammation of airway in bronchial asthma is caused by many complicated elements. Recently, a close attention has been paid to the neurogenic inflammation in airway which is mediated by sensory neuropeptides secreted by sensory nerve in the lung. Neurokinin A (NKA) is an important sensory neuropeptide leading to neurogenic inflammation in airway. Experimental studies showed that NKA has a close relation to asthma. The purpose of the present study was to investigate the changes of NKA in plasma of asthmatic children and possible relationship between sensory neuropeptides and asthma in children. METHODS: Thirty-five children with bronchial asthma were studied; 16 of the cases were < 3 yrs and 19 were >or= 3 yrs. Eighteen of the cases had severe asthma and 16 had mild asthma. None of the subjects was treated with glucocorticoid within 3 days before the study started; 15 healthy children without history of asthma or family history of asthma were enrolled as control subjects. Plasma was collected from each case during acute attack of asthma and their clinical remission of the asthmatic children. After purifying with SEP-pak C(18), NKA content was detect by enzyme-linked immunosorbent assay (ELISA) as instructed by the manufacturer of the NKA Kit (NKA unit: ng/L). RESULTS: (1) The content of plasma NKA of asthmatic children was significantly higher at the asthma attack (256 +/- 153) than that at their clinical remission stage (70 +/- 66; q = 9.497, P < 0.01) and than that of the normal control group (38 +/- 6; q = 8.599, P < 0.01); no significant difference in plasma NKA was found between the clinical remission stage and the normal control group (q = 1.245, P > 0.05). (2) There was a significant positive correlation between the asthmatic clinical state and the levels of plasma NKA; the contents of plasma NKA at the stage of acute attack in severe asthma (296 +/- 170) were significantly higher than those of the mild asthmatic children (190 +/- 99; q = 3.77, P < 0.05). CONCLUSIONS: The contents of plasma NKA were significantly higher during the asthma attack stage of children, and the higher was the level of NKA, the more severe the attack.; with asthma remission, the contents of plasma NKA decreased to normal; the contents of plasma NKA has a close relation to the asthmatic children.