Different dorsolateral prefrontal activation during an emotionalautobiographical memory task between male and female depressed individuals: a fNIRS study.

Depression in male and female are commonly associated with different prevalence, severity, and, in some cases, distinct syndromes or subtypes. However, only a small amount of research has been conducted to completely understand the underlying neuroanatomical mechanisms. The goal of the current study was to provide neural markers for specific depression therapies by demonstrating the differences in aberrant prefrontal activity between male and female depressed subjects during an emotional autobiographical memory test. The study included 127 young adults who were randomly assigned to one of two groups: male depression (62 participants) or female depression (65 participants). The average oxyhemoglobin levels in the dorsolateral prefrontal cortex throughout the emotional autobiographical memory task were assessed utilizing 53-channel functional near-infrared spectroscopy imaging equipment. The oxy-Hb activation in the left dorsolateral prefrontal cortex (lDLPFC) and right dorsolateral prefrontal cortex (rDLPFC) had no significant interaction between groups and emotional valences. A significant main effect was found between male and female, with female depression groups showing lower oxy-Hb activity in lDLPFC and rDLPFC than male depression groups. Male and female depression patients showed distinct brain activation in the DLPFC during an emotional autobiographical memory test, suggesting potential specific neurological indicators for varied somatic symptoms in male and female depression patients. These distinctions should be taken into account while creating preventive measures.

Different activation in dorsolateral prefrontal cortex between anxious depression and non-anxious depression during an autobiographical memory task: A fNIRS study.

OBJECTIVE: Using functional near-infrared spectroscopy (fNIRS) previous studies have found that activation differences in the dorsolateral prefrontal cortex (DLPFC) during an autobiographical memory task (AMT) under the condition of different emotional valences may be neurophysiological markers of depression and different depression subtypes. Additionally, compared with non-anxious depression, anxious depression presents abnormal hemodynamic activation in the DLPFC. This study aimed to use fNIRS to investigate hemodynamic activation in the DLPFC of depression patients with and without anxiety during AMT triggered by different emotional valence stimuli. METHODS: We recruited 194 patients with depression (91 with non-anxious depression, 103 with anxious depression) and 110 healthy controls from Chinese college students. A 53-channel fNIRS was used to detect cerebral hemodynamic differences in the three groups during AMT. RESULTS: The results showed that: (1) the activation of oxy-Hb in the left DLPFC was significantly higher under positive emotional valence than under negative emotional valence for healthy controls and patients with non-anxious depression, while there was no significant difference between positive and negative emotional valence observed in response to anxious depression; and (2) Oxy-Hb activation under negative emotional valence was significantly higher in the anxious depression group than in the non-anxious depression group. CONCLUSIONS: This study revealed that the hemodynamic hyperactivation of negative emotional valence in the left DLPFC may be due to the neurophysiological differences between anxious and non-anxious patients with depression.

Characteristics of oxyhemoglobin during the verbal fluency task in subthreshold depression: A multi-channel near-infrared spectroscopy study.

OBJECTIVE: Subthreshold depression is an essential precursor and risk factor for major depressive disorder, and its accurate identification and timely intervention are important for reducing the prevalence of major depressive disorder. Therefore, we used functional near-infrared spectroscopic imaging (fNIRS) to explore the characteristics of the brain neural activity of college students with subthreshold depression in the verbal fluency task. METHODS: A total of 72 subthreshold depressed college students (SDs) and 67 healthy college students (HCs) were recruited, and all subjects were subjected to a verbal fluency task (VFT) while a 53-channel fNIRS device was used to collect the subjects' cerebral blood oxygenation signals. RESULTS: The results of the independent samples t-test showed that the mean oxyhemoglobin in the right dorsolateral prefrontal (ch34, ch42, ch45) and Broca's area (ch51, ch53) of SDs was lower than that of HCs. The peak oxygenated hemoglobin of SDs was lower in the right dorsolateral prefrontal (ch34) and Broca's area (ch51, ch53).The brain functional connectivity strength was lower than that of HCs. Correlation analysis showed that the left DLPFC and Broca's area were significantly negatively correlated with the depression level. CONCLUSION: SDs showed abnormally low, inadequate levels of brain activation and weak frontotemporal brain functional connectivity. The right DLPFC has a higher sensitivity for the differentiation of depressive symptoms and is suitable as a biomarker for the presence of depressive symptoms. Dysfunction in Broca's area can be used both as a marker of depressive symptoms and as a biomarker, indicating the severity of depressive symptoms.

Anxiety symptoms without depression are associated with cognitive control network (CNN) dysfunction: An fNIRS study.

Anxiety is a common psychological disorder associated with other mental disorders, with depression being the most common comorbidity. Few studies have examined the neural mechanisms underlying anxiety after controlling for depression. This study aimed to explore whether there are differences in cortical activation in anxiety patients with different severities whose depression are normal. In the current study, depression levels were normal for 366 subjects-139 healthy subjects, 117 with mild anxiety, and 110 with major anxiety. Using the Hospital Anxiety and Depression Scale (HADS) and a verbal fluency task (VFT) to test subjects' anxiety and depression and cognitive function, respectively. A 53-channel guided near-infrared spectroscopic imaging technology (fNIRS) detected the concentration of oxyhemoglobin (oxy-Hb). Correlation analysis between anxiety severity and oxy-Hb concentration in the brain cortex was performed, as well as ANOVA analysis of oxy-Hb concentration among the three anxiety severity groups. The results showed that anxiety severity was significantly and negatively correlated with oxy-Hb concentrations in the left frontal eye field (lFEF) and in the right dorsolateral prefrontal area (rDLPFC). The oxy-Hb concentration in the lFEF and the rDLPFC were significantly lower in the major anxiety disorder group than that in the control group. This suggests that decreased cortical activity of the lFEF and rDLPFC may be neural markers of anxiety symptoms after controlling for depression. Anxiety symptoms without depression may be result from the dysfunction of the cognitive control network (CCN) which includes the lFEF and rDLPFC.

Temperature-Sensitive Aerogel Using Bagasse Carboxylated Cellulose Nanocrystals/N-Isopropyl Acrylamide for Controlled Release of Pesticides.

Temperature-sensitive carboxylated cellulose nanocrystals/N-isopropyl acrylamide aerogels (CCNC-NIPAMs) were developed as novel pesticide-controlled release formulas. Ammonium persulfate (APS) one-step oxidation was used to prepare bagasse-based CCNCs, and then the monomer N-isopropyl acrylamide (NIPAM) was successfully introduced and constructed into the temperature-sensitive CCNC-NIPAMs through polymerization. The results of the zeta potential measurement and Fourier infrared transform spectrum (FTIR) show that the average particle size of the CCNCs was 120.9 nm, the average surface potential of the CCNCs was -34.8 mV, and the crystallinity was 62.8%. The primary hydroxyl group on the surface of the CCNCs was replaced by the carboxyl group during oxidation. The morphology and structure of CCNC-NIPAMs were characterized via electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), compression performance, porosity analysis, and thermogravimetric (TG) analysis. The results demonstrate that CCNC-NIPAM has a high porosity and low density, as well as good thermal stability, which is conducive to loading and releasing pesticides. In the swelling, drug loading, and controlled release process, the CCNC-NIPAM exhibited significant temperature sensitivity. Under the same NIPAM reaction amount, the equilibrium swelling rate of the CCNC-NIPAM first increased and then decreased with increasing temperature, and the cumulative drug release ratio of the CCNC-NIPAM at 39 °C was significantly higher than that at 25 °C. The loading efficiency of the CCNC-NIPAM on the model drug thiamethoxam (TXM) was up to 23 wt%, and the first-order model and Korsmyer-Peppas model could be well-fitted in the drug release curves. The study provides a new method for the effective utilization of biomass and pesticides.

Dorsolateral prefrontal activation in depressed young adults with and without suicidal ideation during an emotional autobiographical memory task: A fNIRS study.

OBJECTIVE: Previous studies have proved that there is a strong association between dorsolateral prefrontal cortex and mood symptoms. This study aimed at using functional near-infrared spectroscopy technology to invest brain activity in dlPFC of depressed individuals with and without suicidal ideation during emotional autobiographical memory test, and to understand their differences in brain cognitive mechanisms. It is helpful to improve our ability to predict and subsequently to prevent suicide. METHODS: 85 young adults participated in the study by a simple random sampling method, with health control (34participants), depression with suicidal ideation (17participants), and depression without suicidal ideation (34participants). The average oxyhemoglobin in dlPFC of subjects during EAMT was collected by a 53-channel fNIRS imaging device. RESULTS: A marginal significant difference was found between three groups in left dlPFC and right dlPFC. Post hoc analysis revealed that: (1) under negative emotion, depression without suicidal ideation group had higher activation than healthy control group in left dlPFC. (2) under positive emotion, depression with suicidal ideation group had lower activation than healthy control in right dlPFC. CONCLUSIONS: Results indicated that the depressed individuals with suicidal ideation had some deficits in executive function in right dlPFC, while the depressed adults without suicidal ideation may have mechanism of resource compensatory recruitment in left dlPFC and the dlPFC abnormality involved in the pathophysiology, may localize within left hemisphere. The depressed individuals with and without suicidal ideation had the different mechanisms in dlPFC and fNIRS can be a neuroimaging biomarker characterizing or predicting suicidality in depressed individuals.

Theta-burst stimulation of TMS treatment for anxiety and depression: A FNIRS study.

BACKGROUND: This study aimed to evaluate the intervention effect of intermittent Theta burst stimulation (iTBS) on anxiety and depression by using Functional Near-Infrared Spectroscopy technology for confirming the effect of iTBS on anxiety and depression and providing new parameter basis for the treatment and development of rTMS. METHOD: 37 patients with anxiety and depression were treated with rTMS intervention in iTBS mode, and the symptoms of depression and anxiety were assessed by Hospital Anxiety and Depression Scale at baseline and after 10 times of treatments. The brain activation was assessed by verbal fluency task. The scores of anxiety and depression were analyzed by paired sample t-test. RESULTS: After 10 times of rTMS treatment in iTBS mode, the symptoms of anxiety and depression in patients were relieved. The anxiety scores before and after treatment were significantly different, and the post-test scores were significantly lower than the pre-test scores. Significant differences in depression scores were observed before and after treatment, and the post-test score was significantly lower than the pre-test score. In the brain functional connection, the connection of various brain regions was strengthened, and the strength of functional connection between all ROIs before the intervention was significantly lower than that after the intervention. Statistical significance was observed. CONCLUSION: The intervention of iTBS model has a positive effect on improving symptoms and strengthening brain functional connection of patients with anxiety and depression. This performance supports the effectiveness of iTBS model in treating anxiety and depression.

Dorsolateral Prefrontal Activation in Emotional Autobiographical Task in Depressed and Anxious College Students: An fNIRS Study.

OBJECTIVE: The dorsolateral prefrontal cortex (dlPFC) is strongly associated with mood symptoms. This study used functional near-infrared spectroscopy (fNIRS) technology to explore the features of brain neural activity in the dlPFC of anxious and depressed college students, during an emotional autobiographical memory task, and to understand the differences in brain cognitive mechanisms caused by anxiety and depression. METHODS: A simple random sampling method was used to test 440 college students at a university with a healthy control group (HC, 220 participants), a pure depression group (PD, 92 participants), and a pure anxiety group (PA, 128 participants). The average oxyhemoglobin in the dlPFC of the subjects during the emotional autobiographical memory task was collected by a 53-channel functional near-infrared spectroscopy imaging device. RESULTS: The activation of the left dlPFC (ch13) in the pure depression group was significantly higher than in the pure anxiety group. The activation of the right dlPFC (ch48) was significantly higher under positive emotions than under negative emotions. The interaction between emotion valence and group was marginally significant, and the activation of the right dlPFC (ch41) in the pure depression group was significantly higher under positive emotion than in negative emotion. The activation of the pure depression group under positive emotions was significantly higher than that of the pure anxiety group. In comparison, the activation of the pure depression group under negative emotions was significantly lower than that of the healthy control group. The results of correlation analysis showed that the activation of the left dlPFC (ch13) was significantly negatively correlated with anxiety in positive emotions, but the activation of the right dlPFC (ch34, ch42) was significantly positively correlated with anxiety in positive and negative emotions. CONCLUSIONS: The right dlPFC was insensitive to positive emotions in college students with high-anxiety symptoms, whereas this region was insensitive to negative emotions in college students with high depressive symptoms, which might be one of the critical differences in the cognitive mechanisms of anxiety and depression. Furthermore, left and right dlPFC activation correlated differently with anxiety. The higher the anxiety level, the lower the activation on the left side, and the higher the activation on the right side. The results suggested that anxiety might reduce the function of the left dlPFC.

A high-precision synchronous signal acquisition device.

The synchronous and accurate acquisition of multiple features of states is key to assessing the state of power equipment. The highest recorded accuracy of currently available synchronous signal measuring devices in intelligent substations is the 0.2 class, which cannot satisfy the requirements of power equipment such as voltage and current transformers. The accuracy of measurement of a high-precision sigma-delta analog-to-digital converter (ADC) can reach the 0.05 class, but the phase error among several sigma-delta ADCs is large and dynamic because of inadequate real-time sampling. To solve this problem, this paper proposes a double-trigger-time digital conversion technology for synchronous and accurate measurement among sigma-delta ADCs. The results of tests show that its measurement accuracy can reach the 0.05 class.

The DEAD-Box RNA Helicase DDX3 Interacts with NF-κB Subunit p65 and Suppresses p65-Mediated Transcription.

RNA helicase family members exhibit diverse cellular functions, including in transcription, pre-mRNA processing, RNA decay, ribosome biogenesis, RNA export and translation. The RNA helicase DEAD-box family member DDX3 has been characterized as a tumour-associated factor and a transcriptional co-activator/regulator. Here, we demonstrate that DDX3 interacts with the nuclear factor (NF)-κB subunit p65 and suppresses NF-κB (p65/p50)-mediated transcriptional activity. The downregulation of DDX3 by RNA interference induces the upregulation of NF-κB (p65/p50)-mediated transcription. The regulation of NF-κB (p65/p50)-mediated transcriptional activity was further confirmed by the expression levels of its downstream cytokines, such as IL-6 and IL-8. Moreover, the binding of the ATP-dependent RNA helicase domain of DDX3 to the N-terminal Rel homology domain (RHD) of p65 is involved in the inhibition of NF-κB-regulated gene transcription. In summary, the results suggest that DDX3 functions to suppress the transcriptional activity of the NF-κB subunit p65.

Ubiquitin ligase Fbw7 restricts the replication of hepatitis C virus by targeting NS5B for ubiquitination and degradation.

The nonstructural protein 5B (NS5B) of hepatitis C virus (HCV) is an RNA-dependent RNA polymerase (RdRp) and responsible for replicating the whole HCV genome with help of viral and cellular proteins. However, how cellular factors influence NS5B and, in turn, regulating HCV replication are still poorly defined. The well known tumor suppressor Fbw7, a component of E3 ubiquitin ligase SCF(Fbw7), targets oncoproteins or cellular regulatory proteins for ubiquitin-mediated degradation through a highly conserved binding site called a Cdc4 phosphodegron (CPD). But little is known about whether Fbw7 plays a role in regulation of viral proteins. In this study, we revealed that the conserved CPD is shared by NS5B of almost all genotype of HCV and our data demonstrated that NS5B is a bona fide substrate of Fbw7. Forced expression of Fbw7 promoted the ubiquination of NS5B and negatively regulated its turnover in the proteasome-dependent manner. We further revealed the interaction between NS5B and Fbw7, which resulted in the relocation of Fbw7 from nucleus to cytoplasm. During HCV replication, ectopic expression of Fbw7 could strongly down-regulate NS5B level and consequently inhibited the virus replication. When endogenous Fbw7 was knocked down, both NS5B protein abundance and HCV replication were remarkably up-regulated. The results provide more insights into the interplay of HCV and cellular factors and shed light on molecular mechanisms of HCV replication and pathogenesis.

Functional screen reveals SARS coronavirus nonstructural protein nsp14 as a novel cap N7 methyltransferase.

The N7-methylguanosine (m7G) cap is the defining structural feature of eukaryotic mRNAs. Most eukaryotic viruses that replicate in the cytoplasm, including coronaviruses, have evolved strategies to cap their RNAs. In this report, we used a yeast genetic system to functionally screen for the cap-forming enzymes encoded by severe acute respiratory syndrome (SARS) coronavirus and identified the nonstructural protein (nsp) 14 of SARS coronavirus as a (guanine-N7)-methyltransferase (N7-MTase) in vivo in yeast cells and in vitro using purified enzymes and RNA substrates. Interestingly, coronavirus nsp14 was previously characterized as a 3'-to-5' exoribonuclease, and by mutational analysis, we mapped the N7-MTase domain to the carboxy-terminal part of nsp14 that shows features conserved with cellular N7-MTase in structure-based sequence alignment. The exoribonuclease active site was dispensable but the exoribonuclease domain was required for N7-MTase activity. Such combination of the 2 functional domains in coronavirus nsp14 suggests that it may represent a novel form of RNA-processing enzymes. Mutational analysis in a replicon system showed that the N7-MTase activity was important for SARS virus replication/transcription and can thus be used as an attractive drug target to develop antivirals for control of coronaviruses including the deadly SARS virus. Furthermore, the observation that the N7-MTase of RNA life could function in lieu of that in DNA life provides interesting evolutionary insight and practical possibilities in antiviral drug screening.

Low-molecular-weight protein (LMP)2/LMP7 abnormality underlies the downregulation of human leukocyte antigen class I antigen in a hepatocellular carcinoma cell line.

BACKGROUND: Tumor cells may alter the expression of numerous components involved in antigen-processing machinery to decrease human leukocyte antigen (HLA) class I expression, allowing the tumor cells to escape immune surveillance. The purpose of the present study was to investigate the involvement of these components in the downregulation of HLA class I expression in human hepatocellular carcinoma cell line BEL7,404. METHODS: Expression of HLA-I and antigen presentation-related genes were analyzed by flow cytometry and polymerase chain reaction. The HLA class I-deficient BEL7,404 cell was transfected with the low-molecular-weight protein (LMP) 2 and LMP7 gene and were analyzed by flow cytometry for restoration of surface HLA class I expression. RESULTS: The BEL7,404 cells downregulated the expression of HLA class I antigen and lacked expression of LMP2 and LMP7. Interferon (IFN)-gamma treatment increased the expression of LMP2 but not LMP7. The LMP2-transfected BEL7,404 cells or LMP2 and LMP7-cotransfected cells restored surface HLA class I expression while LMP7-transfected cells did not. However, in IFN-gamma-treated BEL7,404 cells, transfection with the LMP7 gene induced more HLA class I expression than mock transfection. CONCLUSIONS: The LMP2 gene was required for the expression of HLA class I molecules in BEL7,404. The LMP7 was not the major reason for loss of HLA class I in BEL7,404 cells, although the supply of exogenous LMP7 could increase surface expression of HLA class I antigen.

[Characterization of antigenic epitopes of ORF2 encoded proteins of hepatitis E virus genotype 4 identified in China].

To characterize antigenic epitopes of hepatitis E virus (HEV) genotype 4 that was first identified in China a few years ago, a recombinant protein, p166Chn, encoded by HEV genotype 4 ORF2 was used to prepare anti-p166Chn McAbs. Simultaneously, twenty N- or C-terminal truncated p166Chn proteins were generated. Immunoreactivity between the McAbs and the truncated proteins as well as seven p166 recombinant proteins derived from different HEV genotypes and subgenotypes was detected by indirect ELISA, Western blot and competition inhibition ELISA. Two reactive profiles were observed with different McAbs and different truncated proteins. The McAbs, represented by 1G10, reacted with those N-terminal truncated proteins beginning at upstream of aa477 and those C-terminal truncated proteins ending at down-stream of aa613, suggesting that the epitope recognized by 1G10 relied on the region of aa477aa613 and was conformation-dependent. While McAb 2F11 was reactive to those truncated p166Chn proteins beginning at upstream of aa474 or ending at downstream of aa617, indicating that the epitope recognized by 2F11 was also conformation-dependent and relied on a longer peptide of aa474aa617. However, the two groups of McAbs didn't inhibit each other when tested by a competition inhibition ELISA, which confirmed the different spatial positions of the two epitopes. Furthermore, when p166 proteins derived from different HEV genotypes and subtypes were applied, all of the McAbs prepared against pChn166 of genotype 4 identified in China could react with the proteins of genotype 1, 2 and 3 distributed worldwide. The data suggested that the two identified epitopes were HEV genotype-common and played significant effects on cross immunoreactivity between different HEV genotypes.

[Comparison of content of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside and anthraquinon in different ploidy Radix Polygoni Multiflori].

OBJECTIVE: To investigate the content of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside and anthraquinon in diploid and triploid Radix Polygoni Multiflori. METHODS: 4 batches of Radix Polygoni Multiflori were collected from different districts. The content of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside and anthraquinon in these samples were determined at 320 nm and 254nm wave length by HPLC with Inertsil ODS-3 C18 pillar and acetomitrile: aqua (25:75), methanol: 0.1% phosphoric (85:15) respectively as the mobile phase. RESULTS: The maximum content of 2,3,5,4'-tetrahydroxystilbene-2-0-beta-D-glucoside was diploid Radix Polygoni Multiflori from Deqing Guangdong. The maximum ratio of total anthraquinon was triploid Radix Polygoni Multiflori from Jinxi Guangxi reached 85%. CONCLUSION: The content of anthraquinon varies greatly in the samples from the different producing areas.

[Nuclear gene involves in phenotype of non-syndromic deafness associated with mitochondrial 12S rRNA mutation].

The human mitochondrial 12S rRNA gene mutation at position 1555 associated with non-syndromic deafness and aminoglycoside-induced deafness. Family of Huaiyin in Jiangsu is one of the biggest non-syndromic deafness family in the world. In this family, deafness is maternally inherited. After establishing immortal lymphoblastoid cell lines of the family by EB virus, we analysed 17 lymphoblastoid cell lines derived, respectively, from symptomatic, asymptomatic and controll members of the family. Compared with control members, symptomatic and asymptomatic members both exhibited significant decreases in the rate of growth as well as in the rates of mitochondrial protein synthesis. But the extent of decreases is different and the severity of mitochondrial defect is related with its clinical phenotype. These results supported that the nuclear factor involves in the phenotypic manifestation of the non-syndromic deafness associated with the A1555G mutation.

[Sequence analysis of the connexin 26 genes from a deafness family with A1555G mutation in Huaiyin].

OBJECTIVE: To ascertain whether connexin 26 (Cx26) gene was a nuclear modifier gene in an extensive family with matrilineal nonsyndromic deafness associated with A1555G mutation in Huaiyin, China. METHODS: Following PCR-restriction fragment length polymorphism (PCR-RFLP) with ApaI restriction enzyme, Cx26 genes from 26 cases, with A1555G mitochondrial mutations in this family, and 62 controls (including 2 patrilineal relatives, 10 spouse controls and 50 unrelated controls), were sequenced. RESULTS: Compared with the reference sequence of Cx26 gene, totally four kinds of nucleotide changes,79G -->A, 109G-->A, 341G-->A and 235delC, were detected in a heterozygous form. However, the former three were previously reported polymorphisms, and only the 235delC was a previously described recessive mutation associated with most autosomal nonsyndromic sensorineural hearing loss in Japan and China. Further study showed that the heterozygous 235delC mutation existed in both one individual with mild hearing loss and two individuals with normal hearing. Clinical characterization showed that 235delC mutation did not seem to modify the deafness phenotype due to the A1555G mutation. Moreover, this 235delC mutation was deduced to derive from a married-in control. Finally, there were no co-segregation between the phenotypes of hearing loss and the genotypes for Cx26 genes based on the four kinds of nucleotide changes. CONCLUSIONS: The heterozygous 235delC mutation of the Cx26 gene may not modulate the severity of hearing loss associated with A1555G mutation and Cx26 gene is unlikely to be a modifier gene for hearing loss due to A1555G mitochondrial mutation in this Chinese family.

[Detection of germline mutations in the APC gene with the protein truncation test].

The protein truncation test was established for analyzing mutations in the adenomatous polyposis coli (APC) gene which plays an important role in familial adenomatous polyposis (FAP). The sites of APC mutations and the clinic features of FAP patients were examined to find the relationship between them. Genomic DNA, which was extracted from peripheral blood lymphocytes of 22 FAP patients and the normal colon tissues of 43 sporadic colorectal cancers, were examined for mutations in exon15 of the APC gene by using PCR-TNT T7 Quick Coupled Tanscription/Translation System. The subsequent sequencing was used to confirm the mutation sites. Germline mutations were found in 5 of 22 FAP patients. All of the five mutations showed base pair deletions and led to produce truncated protein. No truncating germline mutation was found in normal tissues of 43 sporadic colorectal cancers. The protein truncation test is a sensitive and accurate technique to detect truncated mutations especially in the large exons of APC gene. It can be used as an routine method for assisting the early diagnosis of the FAP patients.

Sequence analysis of the mitochondrial genome from a large family with maternally inherited nonsyndromic deafness.

OBJECTIVE: To ascertain whether other variations coexist with 1555(A--> G) mutation in the mitochondrial DNA and may aggravate the severity of hearing loss or increase the penetrance of 1555(A--> G) mutation in a large family with maternally inherited nonsyndromic deafness in Huaiyin, Jiangsu province. METHODS: PCR-restriction fragment length polymorphism (PCR-RFLP) was used to screen both the nt1555 and the nt7445 of the mitochondrial DNA from 27 maternal members in the core family; and then the mitochondrial genomes from two maternal members, and the 12S rRNA genes MTRNR1 and tRNA-Ser(UCN) gene MTTS1 from the others, were amplified by PCR-RFLP and were sequenced. RESULTS: 1555(A--> G) mutation in the mitochondrial DNA was reverified to be one of the major factors which cause maternally inherited nonsyndromic deafness and the cosegregation of 955-960(insC) and 1555(A--> G) was present in this family. Moreover, 7449 (insG), a novel homoplasmic mutation in the tRNA-Ser(UCN) gene, was found to co-exist with 1555(A--> G) mutation in two maternal members. CONCLUSION: The cosegregation of 955-960(insC) and 1555(A--> G) implies that 955-960(insC) may synergistically cause hearing loss in the presence of an 1555(A--> G) mutation, serving as an aggravating factor to enhance the sensitivity to aminoglycosides, and may sometimes increase the penetrance of 1555(A--> G) mutation.

Relationship between the downregulation of HLA class I antigen and clinicopathological significance in gastric cancer.

AIM: To discuss the expression of human leukocyte antigen (HLA) class I antigens in gastric cancer and correlate these with pathologic type and TNM stage. METHODS: The expression of HLA class I antigen was detected by immunohistochemistry in 185 specimens of gastric cancer, 20 gastric cancer specimens with lymphatic metastasis and 22 controls of normal gastric mucosa using four monoclonal antibodies. RESULTS: The expression of HLA class I antigen (B/C locus) was significantly downregulated in gastric cancer and in lymphatic metastasis than that in normal gastric mucosa (chi2=7.712, P<0.05). The expression of other HLA class I antigens was also downregulated, but the change was slight. There was no relationship between the downregulation of HLA class I antigen and that of beta2m and LMP2. The expression of HLA class I (B/C locus) was statistically correlated with pathologic stage in gastric adenocarcinoma (chi2=4.164, P<0.05). CONCLUSION: The expression of HLA class I antigen (B/C locus) was obviously downregulated in gastric cancer and in lymphatic metastasis. This abnormal expression would provide the tumor cells with a way to avoid immunological recognition.