Objective To establish the dose-effect curves of chromosome aberrations in human peripheral blood lymphocytes induced by different LET rays,including 60Co γ-rays,252Cf neutrons,14MeV neutrons and 12C heavy ions at low doses,respectively,in order to assess radiation-induced damages after occupational and accidental exposure.Methods Heparinized whole blood samples were irradiated with the various radiation devices and doses ranged from 0 to 1 Gy with the interval of 0.25 Gy.Conventional chromosome culture method was applied with adding colchicines at the beginning and chromosome specimens were prepared after 48 h incubation.The Metafer scanning system was used for automatical finder of chromosome metaphases.The mathematic models were fitted according to aberration data obtained.Results At the dose range of 0 - 1 Gy,the math models of dic + r were linear for 60 Co γrays and linear-quadratics for 252 Cf neutrons,14 MeV neutrons and 12 C heavy ions.The models of ace were linear-quadratic for 60Co γ-rays and 12C heavy ion beams,and linear for 252Cf and 14 MeV neutrons.The models of total aberrations were linear-quadratic for all types of radiation.Conclusions High LET rays have higher biological effects in inducing chromosome aberrations yields compared with low LET rays.Moreover,the severity of damage is 252Cf ＞ 14 MeV neutrons ＞ 12C heavy ions ＞ 60Co γ-rays in turn.Therefore,in the range of low doses,the dic + r may be a better target of radiation damage for high LET radiation.

OBJECTIVETo analyze linkage disequilibrium of 12 short tandem repeat loci on chromosome X (X-STR) among an ethnic Han population from Guilin, Guangxi, and to study the genetic linkage and haplotype distributions of such loci in 2 linkage groups.

METHODS12 X-STR loci including DXS8378, DXS10159, DXS10162, DXS10164, DXS981, DXS6789, DXS7424, DXS101, DXS7133, GATA165B12, GATA31E08 and DXS7423 were genotyped using an AGCU X12 STR PCR Amplification kit. A total of 119 pedigrees were analyzed for linkage and linkage disequilibrium.

RESULTSTwo mutations were found at DXS7424, and 1 mutation was found at DXS10164. A total of 93 haplotypes of DXS10159-DXS10162-DXS10164 were constructed for 261 unrelated males and females, in addition with 167 haplotypes of DXS6789-DXS7424-DXS101-DXS7133. The values of recombination fraction between DXS10159 and DXS10162, DXS10162 and DXS10164, DXS6789 and DXS7424, and DXS7424 and DXS101 were 0.0269, 0.0236, 0.0505 and 0.0438, respectively.

CONCLUSIONLinkage disequilibrium of X-STR does not only depend on physical and genetic distances. There was incomplete linkage relationship between loci on DXS10159-DXS1016-DXS10164 and DXS6789-DXS7424-DXS101 linkage groups.

Adolescent ; Adult ; Asian Continental Ancestry Group ; ethnology ; genetics ; Child ; Child, Preschool ; China ; ethnology ; Chromosomes, Human, X ; genetics ; Female ; Haplotypes ; Humans ; Linkage Disequilibrium ; Male ; Microsatellite Repeats ; Middle Aged ; Pedigree ; Young Adult

PURPOSE: An older female predominance has been reported among chronic cough patients in Western countries, which is considered to be associated with a higher cough sensitivity in females. However, the characteristics of Chinese chronic cough patients remain unclear. This study aimed to explore the age and sex distribution as well as their relationship with cough reflex sensitivity to capsaicin in Chinese chronic cough patients. METHODS: We analyzed the demographic features of 1,882 consecutive chronic cough patients who attended our cough clinic in Guangzhou, China. Cough sensitivity to capsaicin, which was defined as the lowest concentration of capsaicin causing 5 coughs or more (C5), was measured in 539 of the 1,882 patients and 68 healthy volunteers. RESULTS: The mean age of the patients was 43.0 ± 13.7 years and patients aged <50 years accounted for more than two-thirds of the study population. Around 87% of the patients were never-smokers. The proportion of females (51.5%) was almost equal to that of males (48.5%). The pattern of the age and sex distribution was consistently reflected within most common causes of chronic cough, while a female predominance was shown in patients with cough-variant asthma and patients aged ≥50 years. Female patients had higher cough sensitivity to capsaicin than male patients (log C5: 1.58 ± 0.84 vs. 2.04 ± 0.84 μmol/L, P = 0.001), and patients aged ≥50 years had higher cough sensitivity to capsaicin than patients aged <50 years. CONCLUSIONS: In China, patients with chronic cough have a roughly equal sex distribution and a middle-aged predominance, irrespective of a higher cough sensitivity to capsaicin in females and older patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02591550
Age Distribution ; Asian Continental Ancestry Group ; Asthma ; Capsaicin ; China ; Cough ; Female ; Healthy Volunteers ; Humans ; Male ; Reflex ; Sex Distribution