[Predictive value of impedance of leadless pacemaker during implantation on trend changes of pacing threshold].

Objective: To explore the predictive value of the impedance measured during leadless pacemaker Micra implantation on the trend of changes of pacing threshold post implantation. Methods: This is a retrospective cross-sectional study. Patients who received implantation of leadless pacemaker Micra at the Second Xiangya Hospital of Central South University from December 2019 to August 2020 were enrolled. The clinical data and the intraoperative electrical parameters during leadless pacemaker implantation were collected. The impedance and pacing threshold data were analyzed at three time points: immediate release, 5-10 min after release, and after traction test. Receiver operating characteristic (ROC) curves and the area under the curve (AUC) were used to analyze the value of the impedance at immediate release on predicting the trend of changes of pacing threshold post implantation. Results: A total of 21 patients (mean age: (72.2±12.5) years, 12 males) were included. The impedance of 21 patients was (798.1±35.3) Ω immediately after implantation, (800.9±35.6) Ω after 5-10 minutes of release, and (883.6±31.7) Ω after traction test. Impedance was similar between the three time points (P>0.05). The threshold was (0.97±0.11) V/0.24 ms immediately after implantation, (0.95±0.12) V/0.24 ms at 5-10 min after the release, and (0.59±0.06) V/0.24 ms after the traction test. The threshold was significantly lower after the traction test than that immediately after release (P=0.003) and than that at 5-10 minutes after release (P=0.008), suggesting a decreased tendency of the threshold over time. According to the analysis of the ROC curve, the immediate impedance after the release ≥680 Ω could predict the ideal pacing threshold after the traction test (AUC=0.989, 95%CI 0.702-0.964, P<0.001), the prediction sensitivity was 87%, and the specificity was 100%. The pacing threshold would be not ideal with the immediate impedance ≤ 520 Ω (95%CI 0.893-1.000, P<0.001), the sensitivity was 100%, and the specificity was 80%. Conclusions: The impedance immediately after the release has predictive value for the changing trend of threshold post leadless pacemaker Micra implantation. Impedance ≥680 Ω immediately after release is often related with ideal pacing threshold after the traction test. In contrast, the impedance ≤ 520 Ω pacing is often related with unsatisfactory threshold after the traction test, therefore, it is recommended to find a new pacing site to achieve the impedance ≥680 Ω immediately after release during leadless pacemaker Micra implantation.

Photoinduced multistage phase transitions in Ta2NiSe5.

Ultrafast control of material physical properties represents a rapidly developing field in condensed matter physics. Yet, accessing the long-lived photoinduced electronic states is still in its early stages, especially with respect to an insulator to metal phase transition. Here, by combining transport measurement with ultrashort photoexcitation and coherent phonon spectroscopy, we report on photoinduced multistage phase transitions in Ta2NiSe5. Upon excitation by weak pulse intensity, the system is triggered to a short-lived state accompanied by a structural change. Further increasing the excitation intensity beyond a threshold, a photoinduced steady new state is achieved where the resistivity drops by more than four orders at temperature 50 K. This new state is thermally stable up to at least 350 K and exhibits a lattice structure different from any of the thermally accessible equilibrium states. Transmission electron microscopy reveals an in-chain Ta atom displacement in the photoinduced new structure phase. We also found that nano-sheet samples with the thickness less than the optical penetration depth are required for attaining a complete transition.

[Comparison of heart failure and COVID-19 in chest CT features and clinical characteristics].

Objective: To identify the characteristics including clinical features and pulmonary computed tomography (CT) features of heart failure and COVID-19. Methods: This study was a retrospective study. A total of 7 patients with heart failure and 12 patients with COVID-19 in the Second Xiangya Hospital of Central South University between December 1, 2019 and February 15, 2020 were enrolled. The baseline clinical and imaging features of the two groups were statistically analyzed. Results: There was no significant difference in age and sex between the two groups(both P>0.05), but the incidence of epidemiological contact history, fever or respiratory symptoms in the COVID-19 group was significantly higher than that in the heart failure group (12/12 vs. 0, P<0.001; 12/12 vs. 4/7, P=0.013). While the proportion of cardiovascular diseases and impaired cardiac function was significantly less than that of the heart failure group(2/12 vs.7/7, P<0.001；0 vs.7/7, P<0.001). For imaging features, both groups had ground-glass opacity and thickening of interlobular septum, but the ratio of central and gradient distribution was higher in patients with heart failure than that in patients with COVID-19 (4/7 vs. 1/12, P=0.04). In heart failure group, the ratio of the expansion of pulmonary veins was also higher (3/7 vs. 0，P=0.013), and the lung lesions can be significantly improved after effective anti-heart failure treatment. Besides, there were more cases with rounded morphology in COVID-19 group（9/12 vs. 2/7, P=0.048）. Conclusions: More patients with COVID-19 have epidemiological history and fever or respiratory symptoms. There are significant differences in chest CT features, such as enlargement of pulmonary veins, lesions distribution and morphology between heart failure and COVID-19.

[A follow-up study of abnormal mutation in neonatal deafness gene screening].

Objective: To screen, diagnose and follow up the abnormal mutation in the gene screening of neonatal deafness. Methods: A total of 24161 newborns born in Zhuhai Maternal and Child Health Hospital from February 1, 2015 to January 31, 2008 were screened for hearing and deafness genes, and audiological screening, diagnosis and 1-3 years follow-up were carried out for the newborns with positive gene screening. Results: There were 991 cases of deafness gene mutation (533 males and 458 females), and the rate of abnormal mutation was 4.10%(991/24 161). Among them, 921 cases were single heterozygous mutation, 130 cases were failed in primary hearing screening, 11 cases were failed in secondary hearing screening, 8 cases were abnormal in audiological diagnosis finally. In these 8 cases, 3 were diagnosed as otitis media and passed audiological follow-up after cure, 2 cases of single ear sensorineural injury caused by high-risk factors, passed after close audiological follow-up, and the other 3 cases were closely audiological follow-up while none of them were successfully sequenced. All of them were moderate to severe sensorineural deafness, 1 case was heterozygous mutation at 3 loci of GJB2(c.235delC,c.408C>A,c.134G>A), 1 case was heterozygous mutation at 2 loci of GJB2(c.235delC, c.109G>A), and 1 case was single heterozygous mutation of GJB2(c.235delC). The remaining 913 cases who passed the primary screening, secondary screening or hearing diagnosis were followed up for 1 to 3 years. Three cases of multiple heterozygous mutation were found in gene screening(2 cases were SLC26A4 2168A>G, IVS7-2A>G, 1 case was GJB2 c.176_191del 16bp, c.299_300del AT), all of them passed both primary and secondary hearing screening. In these 3 cases, the final audiological diagnosis was moderate sensorineural deafness in both ears, with no improvement in the follow-up of 1-3 years. There were 9 monogenic homozygous mutations, 7 failed in primary hearing screening, 3 failed in secondary hearing screening and also failed in audiological diagnosis and 1-3 years' audiological follow-up, all of whom were GJB2 c.235 del C homozygous mutations, and one of whom had a definite family history of deafness. The remaining 6 cases of homozygous mutation diagnosed by primary screening, secondary screening or hearing diagnosis were GJB2 c109G>A homozygous mutation, and passed the 1-3 years' hearing follow-up. 58 children with mtDNA mutations, including 2 with 12S rRNA 1494C>T homozygous mutation, 47 with 1555A>G homozygous mutation, and 9 with 1555A>G heterozygous mutation, all passed the primary or secondary hearing screening, and were instructed to ban ototoxic drugs for the whole life, and passed the 1-3 years' hearing follow-up. Conclusions: The audiological follow-up of children with monogenic heterozygous mutations in deafness gene screening is generally normal. In case of abnormality, the influencing factors such as otitis media should be excluded at first. In case of unexplained moderate to severe sensorineural deafness, the whole-gene sequencing should be performed to find possible pathogenic factors. The children with homozygous mutation or compound heterozygous mutation in gene screening, most of whom show different degrees of hearing loss, should be followed up for a long time, and provide parents with scientific and reasonable genetic counseling according to the mutation genes and loci,. The hearing of drug-induced deafness gene carriers is normal after birth. Parents should be advised to strengthen prevention and follow-up is generally enough.

[Analysis of the incidence and mortality of leukemia in the cancer registration area of Zhejiang Province from 2010 to 2014].

The incidence and mortality rate of leukemia in the cancer registration areas of Zhejiang Province from 2010 to 2014 were analyzed to depict their epidemiological characteristics. From 2010 to 2014, 3789 new cases were diagnosed as leukemia in Zhejiang cancer registration areas, with a crude incidence rate of 6.47 per 100 000. The age-standardized incidence rate of males (standardized by China census data 2000) was 1.35 times that of females. The age-standardized incidence rate of urban areas was similar to that in rural areas (1.04∶1). From 2010 to 2014, 2 568 cases died due to leukemia, with a crude mortality rate of 4.38 per 100 000. The age-standardized mortality rate of males was 1.44 times that of females. The age-standardized mortality rate of urban areas was 0.99 times that of rural areas. The age-standardized incidence and mortality rate did not show any significant change from 2010 to 2014. The annual percent change of these two metrics was -2.36% (t=-0.62, P=0.579) and -3.46% (t=-2.41, P=0.095).

[Incidence and mortality of thyroid cancer in cancer registries of Zhejiang Province, 2010-2014].

From 2010 to 2014, a total of 17 150 new cases of thyroid cancer (TC) reported in cancer registration areas of Zhejiang province, the crude incidence rate of TC was 29.28/100 000. Using the Chinese Census in 2000 and the World Segi's population as the standard population, the age-standardized incidence rate by Chinese standard population (ASIRC) and by world standard population (ASIRW) were 24.11/100 000 and 20.65/100 000 respectively. 256 TC death cases reported in all, the crude mortality rate was 0.44/100 000, the age-standardized mortality rate by Chinese standard population (ASMRC) and by World standard population (ASMRW) were 0.23/100 000 and 0.23/100 000 respectively. The ASIRC had a upward trend [annual percent change (APC)=28.62%, 95%CI: 21.00%-36.72%, t=13.10, P=0.001], while the ASMRC trend seemed stable (APC=0.73%, 95%CI: -7.47%-9.66%, t=0.27, P=0.803).

[Congenital ear deformity screening and non-invasive correction effect analysis].

Objective:To synchronously perform external auricle examination during neonatal hearing screening, follow up auricle deformity with neonatal disease screening system, and calculate the incidence of auricle deformity, self-healing rate, correction rate, incidence of complications and the relationship with hearing loss in Zhuhai area. Method:According to the diagnostic criteria of auricle deformity, the newborns in Zhuhai Maternal and Child Health Hospital were examined on the spot within 2 months. The deformity auricle was registered and uploaded into the newborn hearing screening system. The newborns were followed up by short message notification 7 days after birth, and then compared with the photo uploading system again. At 14 days, the ears of those who could not self-heal were went on non-invasive correction, and collect of relevant data for summary analysis. Result:Among the 1 073 newborns(2 146 ears), 26(37 ears) with malformed ears were treated with auricular pattern correction.The corrective rates of newborns less than 14 days, 14-30 days and 31-60 days were 95%, 90% and 87% respectively, and the incidence of complications were 50%, 58% and 69%, respectively. Conclusion:The incidence of auricular deformities in neonates is high. The earlier correction the better. The ear deformity can be detected at the earliest stage and missed diagnosis can be avoided by simultaneous hearing screening and ear deformity screening. During the window period of 7-14 d, by monitoring the self-healing rate of the affected ear excessive medical correction can be avoided. By hearing screening system statistics, ear shape malformation is not directly related to hearing loss.

[Hearing assessment and follow-up study of aeonatal deafness gene screening homozygous mutation infants].

Objective:To analyze the hearing assessment characteristics and follow-up of some deafness gene screening homozygous infants in Zhuhai. Method:The clinical data of 28 newborns with homozygous mutations transferred to Zhuhai Maternal and Child Health Hospital from Feb. 1, 2015 to Oct. 25, 2018 in hospitals of Zhuhai City were retrospectively analyzed. All the children were screened for hearing. The hearing characteristics and long-term follow-up results of homozygous mutations at different gene sites were analyzed by auditory diagnosis and behavioral follow-up from 1 to 3 years. Result:Fourteen cases of GJB2 c.109G>A with a homozygous mutation, 11 cases passed the hearing screening, the audiological diagnosis was normal, and the behavior test and follow-up were normal from 1 to 3 years. Hearing screening was not passed in 3 newborns, mild to moderate abnormalities of single or bilateral ears were diagnosed by audiology, 1 000 Hz without positive, and middle ear lesions were diagnosed. Eight cases of GJB2 c.235del C homozygous mutation were followed up by behavioral audiometry and follow-up from 1 to 3 years after cure. Among them, 5 cases were diagnosed as severe hearing impairment of bilateral ears and 3 cases as mild and moderate hearing impairment. One case of GJB3 547G>A homozygous mutation was followed up for 1-3 years, and all of them failed to pass the follow-up of behavioral audiometry and follow-up. Four cases of SLC26A4 IVS7-2A>G, 1 case of SLC26A4 1229C>T homozygous mutation, all of them failed to pass the neonatal hearing screening. All the patients were diagnosed as severe hearing impairment of binaural hearing, and the follow-up of 1-3 years' follow-up did not pass the follow-up tests. Conclusion:GJB2 C.235del C, SLC26A4 IVS7-2A>G locus homozygous mutation infant hearing impairment was mainly severe hearing impairment in bilateral ears, and there was no change in 1-3 years follow-up. GJB2 C.109G A homozygous mutant infants had normal hearing, and it was suggested that they should be followed up closely. It is very important to give correct and reasonable genetic counseling to parents with GJB2 C.109G A homozygous mutation without unnecessary panic.

[Risk factors for pulmonary fibrosis in patients with paraquat poisoning].

Objective: To investigate the risk factors for pulmonary fibrosis in patients with paraquat (PQ) poisoning. Methods: A total of 120 patients with PQ poisoning who were admitted from January 2012 to December 2014 were enrolled. According to the presence or absence of pulmonary fibrosis, the patients were divided into non-pulmonary fibrosis group (67 patients) and pulmonary fibrosis group (53 patients) . The Acute Physiology and Chronic Health Evaluation II (APACHE II) score was obtained on days 1 and 3 of poisoning. Routine blood test results, blood biochemical parameters, and radiological parameters were recorded, and the patients with PQ poisoning were followed up for survival and pulmonary fibrosis. Results: A total of 39 patients with PQ poisoning died, resulting in a mortality rate of 32.5%. There were 53 patients who developed pulmonary interstitial fibrosis, yielding an incidence rate of 44.2%. Compared with the non-pulmonary fibrosis group, the pulmonary fibrosis group had a significantly higher age, a significantly higher dose of PQ, and significantly higher APACHE II scores on days 1 and 3 of poisoning (P<0.01) , as well as significantly higher white blood cell (WBC) count and neutrophil count on day 1, significantly higher levels of urea nitrogen, creatinine, and blood glucose on days 1 and 3, and significantly higher activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (P<0.01) . The logistic regression analysis showed that the dose of PQ, WBC count and neutrophil count on day 1, APACHE II scores on days 1 and 3 of poisoning, levels of urea nitrogen, creatinine, and blood glucose, and activities of AST and ALT were associated with the development of pulmonary fibrosis in patients with PQ poisoning. Conclusion: Oral dose of PQ, APACHE II scores on days 1 and 3 of poisoning, levels of urea nitrogen, creatinine, and blood glucose, activities of AST and ALT, and WBC count and neutrophil count on day 1 are risk factors for pulmonary fibrosis in patients with paraquat poisoning.

Structure of transmembrane subunits gp47 of the foamy virus envelope glycoproteins.

The successful foamy viruses (FVs) infection includes at least two essential events, attachment to the cell surface and fusion of the viral envelope with the cell membrane. For the FVs, membrane fusion between virus and cell is mediated by envelope glycoprotein (Env) transmembrane (TM) subunit gp47. Compared with other retroviruses, FV TM subunit shares a similar but not identical structural characteristic. This paper focuses on in sillico analyses of all 15 available FV TM subunits gp47 based on their amino acid sequences. The hydrophobicity analysis revealed that the 15 FVs gp47 had two prominent hydrophobic regions, the N-terminal fusion peptide (FP) and the C-terminal region, which included a membrane-spanning domain (MSD) and a membrane proximal ectodomain region (MPER). In most FVs gp47, two heptad repeats, the coiled coils characterized by repetition of 7-amino acid-motif, were found to be correspondently located downstream of FP (named "N-HR") and the upstream of MPER (named "C-HR"). Furthermore, the solvent accessibility and secondary structure were predicted for all FVs gp47. These observations suggested that FVs gp47 possessed several fusion domains, which were necessary in the process of lipid membrane fusion between FVs and the target cells.

Association of GSTP1 and XRCC1 gene polymorphisms with clinical outcomes of patients with advanced non-small cell lung cancer.

We investigated the association between the polymorphisms GSTP1 rs1695 and XRCC1 rs1799782 and rs25487 and the clinical outcome of patients with non-small cell lung cancer (NSCLC) receiving cisplatin-based chemotherapy. Genotyping of GSTP1 rs1695 and XRCC1 rs1799782, and rs25487 was conducted by polymerase chain reaction-restriction fragment length polymorphism analysis. By conditional logistic regression analysis, patients carrying the GG genotype of GSTP1 rs1695 and the AA genotype of XRCC1 rs25487 were found to be more highly associated with response to chemotherapy than were those carrying the AA genotype; the ORs (95%CIs) were 0.13 (0.04-0.37) and 3.37 (1.44-8.53), respectively. Presence of the GG genotype of GSTP1 rs1695 and the GA and AA genotypes of XRCC1 rs25487 was associated with overall survival of NSCLC, and the hazards ratios (95%CI) were 4.35 (1.40-17.92), 0.53 (0.31-0.91), and 0.39 (0.18-0.83), respectively. The results of our study suggest that the GSTP1 rs1695 and XRCC1 rs25487 polymorphisms might affect the clinical outcome of patients with advanced NSCLC receiving cisplatin-based chemotherapy.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/GaAs hybrid solar cells with 13% power conversion efficiency using front- and back-surface field.

Planar hybrid solar cells based on bulk GaAs wafers with a background doping density of 10(16) cm(-3) and poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) ( PEDOT: PSS) demonstrated an excellent power conversion efficiency of 8.99%. The efficiency of the cell was enhanced to 9.87% with a back-surface field feature using a molecular beam epitaxially grown n-type GaAs epi-layer. The efficiency and fill factor reach 11.86% and 0.8 when an additional p + GaAs epi-layer is deposited on the surface of the solar cells, which provides a front-surface field. The interface between the high- and low-doped regions in the polymer/GaAs and GaAs formed an electric field that introduced a barrier to minority carriers flow to the substrate and effectively reduced front surface carrier recombination, thereby enhancing light-generated free carrier collection efficiency and open-circuit voltage. Compared with the device without the front- and back-surface field, the fill factor and open-circuit voltage of the hybrid solar cell were improved from 0.76 to 0.8 and from 0.68 V to 0.77V, respectively. The highest efficiency reaches a record 13% when the Zonyl fluorosurfactant-treated PEDOT: PSS is used as a hole-transporting conducting layer for hybrid cells.

A toll-like receptor 3 homologue that is up-regulated by poly I:C and DNA virus in turbot Scophthalmus maximus.

In this study, the gene and promoter sequences of turbot Scophthalmus maximus (Sm) toll-like receptor 3 (Tlr3) were cloned and its mRNA tissue distribution and gene expression in response to polyinosinic:polycytidylic acid (poly I:C) and turbot reddish body iridovirus (TRBIV) challenges were studied in vivo. The smtlr3 gene spans over 4·4 kb with a structure of five exons-four introns and encodes a peptide of 916 amino acids. The putative protein shares the highest sequence identity of 52·8-78·5% with fish Tlr3 and contains a signal peptide sequence, 13 leucine-rich repeat (LRR) motifs, a transmembrane region and a toll/interleukin-1 receptor (TIR) domain. Phylogenetic analysis grouped it with other teleost Tlr3s. A number of transcription factor binding sites were identified in the 1538 bp 5' flanking region of smtlr3, including interferon-stimulated response element (ISRE) and those for interferon regulatory factors (IRF) and signal transducer and activator of transcriptions (STATs) smtlr3 transcripts were expressed ubiquitously with higher levels in the head kidney, heart and digestion organs. They were up-regulated by both poly I:C and TRBIV in immune and non-immune organs, but most strongly in the head kidney. Finally, the smtlr3 exhibited a two-wave induced expression during a five day time course when exposure of S. maximus to poly I:C. These findings provide insights into the role of SmTlr3 in antiviral response.

Immuno-inflammatory regulation effect of mesenchymal stem cell transplantation in a rat model of myocardial infarction.

BACKGROUND: Mesenchymal stem cells (MSC) have recently been shown to possess immunomodulatory properties in vitro and in vivo. The present study aimed to investigate the regulatory effect of MSC transplantation on the immuno-inflammatory response in myocardial infarction (MI). METHODS: MI was induced in Sprague-Dawley rats by left anterior descending coronary artery ligation, and the animals were randomly assigned into the following three groups: sham ( n=8); phosphate-buffered saline (PBS) injected (MI+PBS, n=8); and MSC transplantation (MI+MSC, n=8). BrdU-labeled MSC or PBS was transplanted into peri-infarct myocardium by direct myocardial injection. At 1 and 28 days post-transplantation, cardiac function was evaluated by echocardiography. Transplanted cells were investigated through immunohistochemistry. Lymphocyte cytotoxic activity was evaluated with the crystal violet method. The activity of NF-kappaB and protein expression of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6 and IL-10 in myocardium were assessed by immunohistochemistry and Western blot. RESULTS: Echocardiographic examination revealed that the MSC transplantation prevented left ventricular dilation and dysfunction at 28 days after the operation. BrdU-stained cells were found living in host heart 4 weeks after transplantation. MSC transplantation attenuated the cytotoxic activity of spleen lymphocytes. Transplantation of MSC inhibited the activity of NF-kappaB, attenuated the protein production of TNF-alpha and IL-6, and increased the expression of IL-10 in peri-infarct myocardium. DISCUSSION: MSC transplantation modulated the immuno-inflammatory response in MI. The immuno-inflammatory regulatory effect of MSC transplantation might partly account for the cardiac protection in myocardial infarction.

Characterization of two novel protocadherins (PCDH8 and PCDH9) localized on human chromosome 13 and mouse chromosome 14.

The protocadherins are a subfamily of the calcium-dependent cell-cell adhesion and recognition proteins of the cadherin superfamily. In this study we describe the isolation and characterization of two novel protocadherins, PCDH8 and PCDH9, that constitute a new linkage group on human chromosome 13 and mouse chromosome 14. Like other protocadherins both genes are predominantly expressed in brain, but PCDH9 is also expressed in a broader variety of tissues, and the expression patterns appear to be developmentally regulated. We have determined the genomic organization of PCDH8, which differs significantly from that of the other cadherin subfamilies. In contrast to the classical and desmosomal cadherins, which in general consist of 15-17 exons and share a remarkable degree of conservation in intron position, PCDH8 consists of only three exons and lacks introns in the extracellular domain. The first exon encodes the extracellular domain, the transmembrane region, and part of the cytoplasmic tail. The second exon encodes the remainder of the cytoplasmic region and is partially untranslated. The differences in the genomic structure of cadherin subfamilies will be discussed in the context of the evolution of the cadherin superfamily.

Effectiveness of live-attenuated Japanese encephalitis vaccine (SA14-14-2): a case-control study.

BACKGROUND: Japanese encephalitis is a major cause of death and disability throughout Asia, including the Indian subcontinent. Although an effective vaccine for Japanese encephalitis is available, hundreds of millions of susceptible individuals remain unimmunised because of the vaccine's cost. In 1988, an inexpensive live-attenuated vaccine (SA14-14-2) was licensed in China. We have measured the effectiveness of this vaccine. METHODS: In a case-control study in rural Sichuan Province, China, the 56 cases consisted of children admitted to hospital with acute Japanese encephalitis, and were confirmed serologically. 1299 village-matched and age-matched controls were identified, and vaccination histories obtained from pre-existing written records. FINDINGS: The effectiveness of one dose was 80% (95% Cl 44 to 93%); that of two doses was 97.5% (86 to 99.6%). Controlling for multiple potential confounders did not alter these results. INTERPRETATION: We conclude that a regimen of two doses of live-attenuated Japanese encephalitis vaccine, administered 1 year apart, is effective in the prevention of clinically important disease. Subsequent study is needed to assure the safety of this vaccine.

Effect of chronic irradiation of 60Co-gamma-ray at low dose rate on rhesus monkey - effect on peripheral blood and testis.

The authors have demonstrated that after a long-term chronic irradiation of 2.17 rad/day for 2 months, the testis of the experimental monkey (Macaca mulatta) is extremely atrophied with a loss of reproductive ability. But the effect on peripheral blood is not apparent even after irradiation for 57 months. It should be noted that rhesus monkeys, being as sensitive to irradiation and similar in evolutionary steps as human beings, could be used as experimental animals to further study the dose rate for aspermatogenesis, the morphological injuring effect on the reproductive system and the cytogenetic effect of irradiation, and this is highly important to working out a standard of promised dose of irradiation for X-ray workers and an index or radiation protection monitoring.