[Cloning, sequencing and subcloning of cDNA coding for group I allergen of Dermatophagoides farinae].

OBJECTIVE: To clone, sequence and subclone the cDNA coding for group 1 allergen of Dermatophagoides farinae (Der f 1). METHODS: The cDNA of Der f 1 was amplified by RT-PCR and PCR. After purified, the gene fragment was cloned into a vector pMD-18T. The recombinant plasmid pMD-18T-Der f 1 was transformed into E. coli JM109. Positive clones were screened and identified by PCR and digestion with restriction enzyme. The sequence of inserted Der f 1 gene fragment was also detected. Der f 1 was then subcloned into the vector of pET-32a(+). RESULTS: The Der f 1 gene fragment of Dermatophagoides farinae was specifically amplified from RNA by RT-PCR and PCR. The recombinant plasmid pMD-18T-Der f 1 and pET-32a(+)-Der f 1 was constructed and digested by Bam H I and Sac I, the size of gene fragment was 646 bp and in accordance with the expected one. CONCLUSION: The pET-32a(+)-Der f 1 subcloning has been constructed successfully.

Diarrhea and acaroid mites: a clinical study.

AIM: To explore the characteristics of diarrhea caused by acaroid mites. METHODS: Acaroid mites in fresh stools of 241 patients with diarrhea were separated by flotation in saturated saline. Meanwhile, skin prick test, total IgE and mite-specific IgE were detected in all patients. RESULTS: The total positive rate of mites in stool samples of the patients was 17.01 % (41/241), the positive rates of mites in male and female patients were 15.86 % (23/145) and 18.75 % (18/96), respectively, without significant difference (P>0.05). The percentage of skin prick test as "+++", "++", "+", "+/-" and "-" was 9.13 % (22/241), 7.47 % (18/241), 5.81 % (14/241), 4.98 % (12/241) and 72.61 % (175/241), respectively. The serum levels of total IgE, mite-specific IgE in patients with and without mites in stool samples were (165.72+/-78.55) IU/ml, (132.44+/-26.80) IU/ml and (145.22+/-82.47) IU/ml, (67.35+/-45.28) IU/ml, respectively, with significant difference (P<0.01). The positive rate of mites in stool samples in staffs working in traditional Chinese medicine storehouses or rice storehouses (experimental group) was 26.74 % (23/86), which was significantly higher than that (11.61 %, 18/155) in people engaged in other professions (chi(2)=8.97, P<0.01). CONCLUSION: Acaroid mites cause diarrhea and increase serum levels of total IgE and mite-specific IgE of patients, and the prevalence of diarrhea caused by acaroid mites is associated with occupations rather than the gender of patients.

Acaroid mite, intestinal and urinary acariasis.

AIM: To investigate epidemiology and pathogenic mite species of intestinal and urinary acariasis in individuals with different occupations. METHODS: A total of 1994 individuals were tested in this study. History collection, skin prick test and pathogen identification were conducted. The mites were isolated from stool and urine samples by saturated saline flotation methods and sieving following centrifugation, respectively. RESULTS: Among the 1994 individuals examined, responses to the skin prick test of "+++", "++", "+","+/-" and "-" were observed at frequencies of 3.96 % (79), 3.21 % (64), 2.31 % (46), 1.25 % (25) and 89.27 % (1780), respectively. A total number of 161 (8.07 %) individuals were shown to carry mites, with 92 (4.61 %) positive only for stool samples, 37 (1.86 %) positive only for urine samples and 32 (1.60 %) for both. The positive rate of mites in stool samples was 6.22 % (124/1994), being 6.84 % (78/1140) for males and 5.39 % (46/854) for females. No gender difference was observed in this study (chi(2)=1.77, P>0.05). The mites from stool samples included Acarus siro, TyroPhagus putrescentiae, Dermatophagoides farinae, D. pteronyssinus, Glycyphagus domesticus, G. ornatus, Carpoglyphus lactis and Tarsonemus granaries. The positive rate of mites in urine samples was 3.46 % (69/1994). The positive rates for male and female subjects were found to be 3.95 % (45/1140) and 2.81 % (24/854) respectively, with no gender difference observed (chi(2)=1.89, P>0.05). Mites species in urine samples included Acarus siro, Tyrophagus putrescentiae, T. longior, Aleuroglyphus ovatus, Caloglyphus berlesei, C. mycophagus, Suidasia nesbitti, Lardoglyphus konoi, Glycyphagus domesticus, Carpoglyphus lactis, Lepidoglyphus destructor, Dermatophagoides farinae, D. pteronyssinus, Euroglyphus magnei, Caloglyphus hughesi, Tarsonemus granarus and T. hominis. The species of mites in stool and urine samples were consistent with those separated from working environment. A significant difference was found among the frequencies of mite infection in individuals with different occupations (chi(2)=82.55, P<0.001), with its frequencies in those working in medicinal herb storehouses, those in rice storehouse or mills, miners, railway workers, pupils and teachers being 15.89 % (68/428), 12.96 % (53/409), 3.28 % (18/549), 2.54 % (6/236), 5.10 % (13/255) and 2.56 % (3/117), respectively. CONCLUSION: The prevalence of human intestinal and urinary acariasis was not associated with gender, and these diseases are more frequently found in individuals working in medicinal herb, rice storehouses or mills and other sites with high density of mites. More attention should be paid to the mite prevention and labor protection for these high-risk groups.

L-forms of H. pylori.

AIM: To study the occurrence of L-forms of H. pylori infection in patients with peptic ulcers and its association with possible changes of cellular immune function in the patients. METHODS: Endoscopic biopsy specimens of gastric antrum and gastric corpus were taken from 228 patients with peptic ulcers and inoculated into Skirrow selective medium for H. pylori vegetative forms and special medium for H. pylori L-forms, followed by bacterial isolation and identification. And peripheral venous blood of the patients was taken to detect the percentage of CD3(+), CD4(+) and CD8(+) with biotin-streptavidin (BSA) and the level of IL-2, IL-6 and IL-8 with ELISA. RESULTS: (1) The detection rates of H. pylori L-forms and vegetative forms in the patients were 50.88 % (116/228) and 64.91 % (148/228) respectively, and the co-infection rate of H. pylori L-forms and vegetative forms was 78.38 % (116/148). To be more exact, the detection rates of H. pylori L-forms in male and female patients were 57.04 % (77/135) and 41.94 % (39/93) respectively, and statistics found significant difference between them (P<0.05). Furthermore, the detection rates of H. pylori L-forms in patients aged 14 years-, 30 years-, 40 years- and 50 years- were 31.91 % (15/47), 42.86 % (24/56), 56.94 % (41/72) and 67.92 % (36/53) respectively, and there was significant difference between them (P<0.01). (2) The percentages of CD3(+), CD4(+), CD8(+), the ratio of CD4(+)/CD8(+), and the level of IL-2, IL-6, IL-8 in H. pylori-positive patients were (52.59+/-5.44) %, (35.51+/-5.74) %, (27.77+/-8.64) %, (1.56+/-0.51), (2.66+/-0.47) mg/L, (108.62+/-5.85) ng/L and (115.79+/-7.18) ng/L respectively, compared with those in H. pylori-negative patients, the percentages of CD3(+), CD4(+) and the ratio of CD4(+)/CD8(+) decreased, but the level of IL-2, IL-6 increased, and the difference was significant (P<0.001-P<0.01). Moreover, the percentages of CD3(+), CD4(+), CD8(+), the ratio of CD4(+)/CD8(+), and the level of IL-2, IL-6, IL-8 in the patients with mixed infection of both H. pylori L-forms and vegetative forms were (51.69+/-5.28) %, (34.75+/-5.89) %, (27.15+/-7.45) %, (1.48+/-0.47), (2.16+/-0.38) mg/L, (119.45+/-5.44) ng/L and (123.64+/-6.24) ng/L respectively, compared with those in patients with simple infection of H. pylori vegetative forms, the percentage of CD4(+), the ratio of CD4(+)/CD8(+) and the level of IL-2 increased, but the level of IL-6 and IL-8 decreased, statistical difference was found between them (P<0.001-P<0.05). CONCLUSION: L-forms variation often occurs in patients with peptic ulcers who are infected by H. pylori, which is commonly found in male patients and related to ages. The L-forms variation of H. pylori can be an important factor causing disorder of cellular immune function in the patients with peptic ulcers who are infected by H. pylori.