[Preliminary clinical effect evaluation of digital head and neck radiotherapy oral positioning stents]

Objective: To develop a designing software of digital oral positioning stent for radiotherapy of head and neck, and to compare its clinical effect with traditional oral positioning stents made by lost wax process. Methods: Thirty patients with nasopharyngeal cancer who received oral examination before radiotherapy in the prosthodontics department from July to December, 2021, were selected and divided into three groups according to the patients' wishes, 10 per group: one group without radiotherapy oral positioning stents, one group with traditional oral positioning stents (traditional stents group), and the third group with digital oral positioning stents (digital stents group). Patients' ages range from 20 years old to 71 years old. There were 15 males and 15 females involved in this study. The manufacturing time and comfort of the two positioning stents were evaluated, and the radiation doses of the radiotherapy target areas and surrounding healthy tissues were statistically analyzed at the end of radiotherapy. Results: The manufacturing time of digital stents group [(209±7) min] was much less than that of traditional stents group [(490±10) min] (t=69.85, P<0.001). The comfort of patients' wearing of digital stents [first wearing: 5 (3, 6) score; at the end of radiotherapy: 4 (3, 5) score] was better than that of traditional ones [first wearing: 7 (3, 7) score; at the end of radiotherapy: 7 (3, 7) score] (U=22.00, P=0.033; U=20.50, P=0.023). There was no significant differences in the target radiation doses among the three groups, and the radiation doses of tongue [traditional stents group: (36.74±5.45) Gy; digital stents group: (35.96±4.98) Gy] and mandible [traditional stents group: (35.46±4.19) Gy; digital stents group: (35.34±3.98) Gy] were significantly lower in the patients wearing oral positioning stents than in the patients without oral positioning stents [tongue: (41.49±4.46) Gy; madible: (39.32±3.52) Gy] (P<0.05). Conclusions: Oral positioning stents for nasopharyngeal carcinoma radiotherapy could greatly reduce the exposure doses of tongue and madible of patients. Digital oral positioning stents designed and manufactured by independently developed software had higher production efficiency than the traditional method, and patients' evaluation of comfort was better.

Global leadership initiative in malnutrition (GLIM) criteria using hand-grip strength adequately predicts postoperative complications and long-term survival in patients underwent radical gastrectomy for gastric cancer

BACKGROUND

The present study aims to investigate whether malnutrition defined by the Global Leadership Initiative in Malnutrition (GLIM) criteria using hand-grip strength (HGS) adequately predict postoperative complications and long-term survival in patients underwent radical gastrectomy for gastric cancer in a similar manner to GLIM-defined malnutrition using skeletal muscle index (SMI).

METHODS

Patients who underwent radical gastrectomy for gastric cancer from August 2014 to June 2019 were included in this study. Clinical data were prospectively collected. Malnutrition was diagnosed based on the two-step approach following the GLIM criteria. Skeletal muscle mass was assessed using SMI based on abdominal computed tomography (CT) scans, or assessed using HGS.

RESULTS

A total of 1359 patients were included in this study, in which 36.2% of the patients were at risk of malnutrition (Nutritional Risk Screening 2002 scores ≥3). The incidence of malnutrition was 28.2% and 27.5% using SMI and HGS, respectively. There was a high agreement between the two criteria of malnutrition (kappa = 0.863, P < 0.001). Both of the two criteria of malnutrition were independently associated with postoperative complications (SMI-GLIM, P = 0.041; HGS-GLIM, P = 0.023), overall survival (P < 0.001, both), and disease-free survival (P < 0.001, both), with similar odds ratio or hazard ratio after adjusting for the same confounding variables. HGS-GLIM malnutrition (P = 0.046) but not SMI-GLIM malnutrition (P = 0.270) was associated with a higher incidence of severe complications.

CONCLUSIONS

GLIM criteria using HGS is a useful tool to diagnose malnutrition and has a similar or even better predictive value for postoperative complications and long-term survival after radical gastrectomy for gastric cancer compared with GLIM criteria using SMI.

[Effects of pressure steam sterilization times on the accuracy of the digital intraoral scanning data]

Objective: To provide a scientific basis for the standardized operation of clinical disinfection by comparing and analyzing the influence of disinfection times on the accuracy of digital intraoral scanning. Methods: The author prepared 10 brand-new intraoral scanning heads (Trios, 3Shape, Denmark), scan the same plaster standard dentition model after 1, 20, 40, and 60 times of pressure steam sterilization, and obtained the data of four groups of experimental groups A, B, C, D, and scan the model 5 times repeatedly after each disinfection cycle of each scanning head. A model scanner (D2000, 3Shape, Denmark) was used to scan the standard dentition model, and the scan results were used as the control group data. Vernier calipers and measurement software were used to measure the arch length (the distance between the mesial cheek tips of the first molars on both sides of the maxillary) and the front and back length (the distance from the tongue protrusion of the right incisor to the buccal tip of the first molar on the right of the upper jaw) of the plaster model and the data of the 4 experimental groups. The line distance results of the 4 groups of experimental groups were compared for statistical analysis, and the trueness and precision values of the 4 groups of experimental groups were compared for statistical analysis. Results: The length of the arch across the 4 experimental groups increased with the increase in the number of disinfection (P<0.05), and there were statistical differences compared with the measurement results of the plaster model (P<0.05); the differences in the length of the dental arch were not statistically significant (P>0.05). The treness of the 4 experimental groups is statistically significant (P<0.05), and the trueness was from high to low in order of group A [(114.85±3.75) μm], group B [(124.65±3.85) μm], group C [(131.45±3.04) μm] and group D [(144.64±3.34) μm]; the precision of the 4 experimental groups was not statistically significant (P>0.05). Conclusions: The number of times of pressure steam sterilization can affect the accuracy of the scanning results of the digital intraoral scanner, and with the increase of the number of sterilizations, the error of the scanning results also tends to increase. The number of sterilizations has no effect on the repeatability of the digital scanning results. The increase in the number of times of pressure steam sterilization affects the accross of the arch but has no effect on the length of the dental arch, and the range of change of the length of the arch is within the clinically acceptable range. After 60 times of pressure steam sterilization, the accuracy of digital scan data can still meet clinical needs.

[Analysis of Changes and Factors Influencing Air Pollutants in the Beijing-Tianjin-Hebei Region During the COVID-19 Pandemic]

A series of strict control measures were imposed in the Beijing-Tianjin-Hebei region in early 2020 to control the spread of COVID-19. These measures have led to a reduction of anthropogenic air pollutants, providing an opportunity to observe the contribution of human activities to local air pollution. In this study, the control period was divided into four stages:the before, early, middle, and later stages. Based on a variety of data including meteorological, traffic, and industrial manufacturing datasets, statistical methods were combined with spatial analysis to evaluate changes in air pollution and associated human impacts during each stage. In addition, suggestions are made for further regional air pollution control in the Beijing-Tianjin-Hebei area. Key results are as follows:① Overall, the AQI and the concentrations of six air pollutants, especially SO₂, PM₁₀, and NO₂, were lower during control period than during the equivalent period in 2019 (reductions of 26.5%, 24.3%, and 16.9%, respectively). From the before to later stages, pollutants (except O₃) showed a downward trend while O₃ increased significantly during the before stage (by 76.2%) and the growth rate slowed during the middle and later stages; ②During the prior stage, Beijing experienced two periods with heavy air pollution days as a result of the local accumulation of pollutants, secondary transformation, and regional transport. The concentration of PM_2.5 in February was nearly 60% lower than in February 2014 under similar meteorological conditions in Beijing; ③ Following an increase in traffic volume and industrial activity, changes in air pollutants tended to be stable or slightly increase during the middle and later stages of the control period. The grey relation coefficients between thermal radiation intensity anomalies and the main pollutants in heavy industrial cities were greater than 0.6, which means that the control of industrial emissions remains key to controlling air pollution.

The relationship between the GLIM-defined malnutrition, body composition and functional parameters, and clinical outcomes in elderly patients undergoing radical gastrectomy for gastric cancer

OBJECTIVE

The present study aims to determine the correlations between Global Leadership Initiative in Malnutrition (GLIM)-defined malnutrition and body composition and functional parameters, and to comprehensively analyze the predictive value of GLIM-defined malnutrition for postoperative outcomes in the context of detailed measurement of body composition and functional parameters in elderly patients who underwent radical gastrectomy for gastric cancer.

METHODS

Elderly patients (aged ≥65 years) who underwent radical gastrectomy for gastric cancer from August 2014 to June 2019 were included. Malnutrition was diagnosed using the GLIM criteria. Skeletal muscle index (SMI), skeletal muscle density (SMD), subcutaneous fat area (SFA), and visceral fat area (VFA) were analyzed using abdominal computed tomography (CT) images. Handgrip strength and 6-m gait speed were measured.

RESULTS

A total of 597 elderly patients were included in this study, in which 45.7% were at risk of malnutrition identified using Nutritional Risk Screening 2002 (NRS 2002), and 34.5% were diagnosed with malnutrition. Patients with malnutrition had lower SMI, SMD, SFA, VFA, lower handgrip strength and gait speed. Low handgrip strength and age ≥80 years were independent risk factors for postoperative complications, rather than GLIM-defined malnutrition. GLIM-defined malnutrition was independently associated with overall survival and disease-free survival after adjusting to the body composition and functional parameters in the multivariate analyses.

CONCLUSIONS

GLIM-defined malnutrition was a better predictive factor than single parameters of body composition or physical function for survival in elderly gastric cancer patients. Handgrip strength can be used as a supportive measure to further improve the definition of malnutrition.

[Effects and mechanism of pyrroloquinoline quinine on mitochondrial function and cell survival of rat bone marrow mesenchymal stem cells under oxidative stress]

Objective: To observe the effects of pyrroloquinoline quinine (PQQ) on the mitochondrial function and cell survival of rat bone marrow mesenchymal stem cells (BMSCs) under oxidative stress, and to explore its mechanism. Methods: BMSCs of rats were cultured in vitro with Dulbecco's minimum essential medium/F12 medium containing fetal bovine serum in the volume fraction of 10% (hereinafter referred to as normal medium). The rat BMSCs of third to fifth passages in logarithmic growth phase were selected for the following experiments. (1) The cells were divided into normal control group, normal control+ PQQ group, hydrogen peroxide (H(2)O(2)) alone group, and H(2)O(2)+ PQQ group. The cells in normal control group were cultured in normal medium for 24 hours; the cells in normal control+ PQQ group were cultured in normal medium containing 100 μmol/L PQQ for 24 hours; the cells in H(2)O(2) alone group were cultured in normal medium containing 200 μmol/L H(2)O(2) for 24 hours; the cells in H(2)O(2)+ PQQ group were pre-incubated with normal medium containing 100 μmol/L PQQ for 2 hours, and then with H(2)O(2) added to the concentration of 200 μmol/L and cultured for 24 hours. The cell morphology of each group was observed under the inverted phase contrast microscope, and the cell survival rate was detected by cell count kit 8 method. (2) Five batches of cells were collected, and the cells of each batch were divided into normal control group, H(2)O(2) alone group, and H(2)O(2)+ PQQ group. The cells in each group received the same treatment as that in the corresponding group of experiment (1). After 24 hours of culture, one batch of cells was collected for apoptosis detection by flow cytometry, and the apoptosis rate was calculated. One batch of cells was subjected to mitochondrial membrane potential assay and JC-1 fluorescent staining observation using the JC-1 mitochondrial membrane potential detection kit and the inverted phase contrast fluorescence microscope, respectively. One batch of cells was collected for mitochondrial morphology observation under the transmission electron microscope. One batch of cells was subjected to catalase (CAT) and superoxide dismutase (SOD) activity assay by CAT activity assay kit and SOD activity assay kit, respectively. One batch of cells was subjected to Western blotting for determination of protein level of Epac1, adenine monophosphate activated protein kinase (AMPK), phosphorylated AMPK, cysteinyl aspartate-specific proteinase 3 (caspase-3), and cleaved caspase-3, and the phosphorylation level of AMPK and cleaved caspase-3/caspase-3 ratio were calculated. Six replicates were measured in each group for each index except for morphological observation. Data were statistically analyzed with one-way analysis of variance and independent sample equal variance t test. Results: (1) After 24 hours of culture, compared with those in normal control group (the cell survival rate was set to 100.0%), there was an increase in cell vacuole and a decrease in cell number in H(2)O(2) alone group, and the cell survival rate was significantly reduced to (74.3±2.9)% (t=6.39, P<0.01). Compared with those in H(2)O(2) alone group, the cell morphology of H(2)O(2)+ PQQ group was significantly improved, and the cell survival rate was significantly increased to (116.9±4.2)% (t=6.92, P<0.01); the cell survival rate in normal control+ PQQ group was (101.2±1.1)%, close to that of control group (t=1.06, P>0.05). (2) After 24 hours of culture, compared with (13.6±1.0)% in normal control group, the apoptosis rate of cells in H(2)O(2) alone group was significantly increased to (37.1±2.0)% (t=10.57, P<0.01). Compared with that in H(2)O(2) alone group, the apoptosis rate of cells in H(2)O(2)+ PQQ group was significantly declined to (17.0±0.7)% (t=9.49, P<0.01). (3) After 24 hours of culture, compared with those in normal control group, the mitochondrial membrane potential of cells in H(2)O(2) alone group was depolarized, the JC-1 fluorescent dye mainly existed in the cytoplasm in the form of monomer, which emitted green fluorescence, and a significant decrease in mitochondrial membrane potential was shown (t=4.18, P<0.01). Compared with those in H(2)O(2) alone group, the mitochondrial membrane potential of cells in H(2)O(2)+ PQQ group was increased to normal level (t=4.43, P<0.01), and the JC-1 fluorescent dye accumulated in mitochondria following the polarized mitochondrial membrane potential and emitted red fluorescence. (4) After 24 hours of culture, compared with that in normal control group, the mitochondrial structure of cells in H(2)O(2) alone group was disordered, with disappeared mitochondrial cristae and decreased mitochondrial matrix density. Compared with that in H(2)O(2) alone group, the mitochondrial structure of cells in H(2)O(2)+ PQQ group was regular and intact, with clearly visible mitochondrial cristae and increased mitochondrial matrix density. (5) After 24 hours of culture, compared with those in normal control group, the CAT activity of cells in H(2)O(2) alone group was significantly increased (t=4.54, P<0.05), and the SOD activity was significantly decreased (t=3.93, P<0.05). Compared with those in H(2)O(2) alone group, the CAT activity of cells in H(2)O(2)+ PQQ group was obviously increased (t=8.65, P<0.01), while there was no significant change in the SOD activity (t=0.72, P>0.05). (6) After 24 hours of culture, compared with those in normal control group, the protein expression of Epac1 of cells in H(2)O(2) alone group was significantly decreased (t=4.67, P<0.01), while the AMPK phosphorylation level and the cleaved caspase-3/caspase-3 ratio were significantly increased (t=7.88, 3.62, P<0.01). Compared with those in H(2)O(2) alone group, the protein expression of Epac1 and the AMPK phosphorylation level of cells in H(2)O(2)+ PQQ group were both significantly increased (t=4.34, 16.37, P<0.01), while the cleaved caspase-3/caspase-3 ratio was significantly declined (t=3.17, P<0.05). Conclusions: Pretreatment with PQQ can improve the mitochondrial function, reduce cell apoptosis rate, and enhance cell survival rate of rat BMSCs under oxidative stress, which may be related to the up-regulation of Epac1 protein expression, activation of AMPK signaling pathway, and down-regulation of cleaved caspase-3 protein level.

Antidepressant effect of taurine in chronic unpredictable mild stress-induced depressive rats

Depression, a psychiatric and dysthymic disorder, severely affects the learning, work and life quality. The main pathogenesis of depression is associated with central nervous system (CNS) dysfunction. Taurine has been demonstrated to exert protective effects on the brain development and can improve learning ability and memory. Our study investigated the antidepressant-like effects of taurine pre-treatment by examining the changes in depression-like behavior, hormones, neurotransmitters, inflammatory factors and neurotrophic factors in the hippocampus of a chronic unpredictable mild stress (CUMS)-induced depressive rat model. Taurine was found to inhibit the decrease of sucrose consumption and prevent the deficiency of spatial memory and anxiety in rats exposed to CUMS, suggesting a preventive effect of taurine on depression-like behavior. Furthermore, the decreased levels of 5-hydroxytryptamine, dopamine, noradrenaline; the increased levels of glutamate, corticosterone; and the decreased expressions of fibroblast growth factor-2, vascular endothelial growth factor and brain derived neurotrophic factor in depressive rats were hindered by taurine pre-administration. However, tumor necrosis factor-α and interleukin-1β levels were not significantly changed by taurine. The results demonstrated that the anti-depressive effect of taurine may be involved in the regulation of hypothalamic-pituitary-adrenal (HPA) axis and the promotion of neurogenesis, neuronal survival and growth in the hippocampus.

[Effects of human amniotic epithelial stem cells-derived exosomes on healing of wound with full-thickness skin defect in rats]

Objective: To investigate the effects of human amniotic epithelial stem cells-derived exosomes on healing of wound with full-thickness skin defect in rats. Methods: (1) Human amniotic epithelial stem cells were isolated from the amnion tissue of 5 full-term pregnant women in Department of Obstetrics of our hospital by the method of trypsin digestion, and their morphology was observed. The third passage of cells were stained with rhodamine-phalloidin for cytoskeleton observation. The third passage of cells were identified with flow cytometry through the detection of expressions of cell surface markers CD29, CD31, CD34, CD90, CD105, SSEA3, SSEA4 and immunity-related marker human leukocyte antigen-D related site (HLA-DR). The third passage of cells were also assessed the ability of adipogenic and osteogenic differentiation. (2) The third passage of human amniotic epithelial stem cells were cultured in DMEM medium supplemented with 10% exosome-free fetal bovine serum. Exosomes were isolated from culture supernatant by the method of ultracentrifugation and represented with scanning electron microscope for morphologic observation. (3) Six adult SD rats were anesthetized, and four 1 cm×1 cm sized wounds with full-thickness skin defect were made on the back of each rat. The wounds on the back of each rat were divided into control group, 25 μg/mL exosomes group, 50 μg/mL exosomes group, and 100 μg/mL exosomes group according to the random number table (with 6 wounds in each group), and a total volume of 100 μL phosphate buffered saline, 25 μg/mL exosomes, 50 μg/mL exosomes, and 100 μg/mL exosomes were evenly injected around the wound through multiple subcutaneous sites, respectively. The wound healing rate was calculated based on measurement on post injury day (PID) 7, 14, and 21. On PID 21, the healed wound tissue of each group was collected and stained with HE to observe and count skin accessories, and the arrangement of collagen fibers was observed with Masson staining. Data were processed with analysis of variance for repeated measurement, analysis of variance of randomized block design, one-way analysis of variance, and Bonferroni test. Results: (1) The cells, which were isolated and cultured, displayed typical cobblestone morphology with many microvilli on cell surface. Among the cells, the positive expression rates of CD29, CD90, SSEA3, and SSEA4 were above 50.0%, and the rate of CD105 was 8.0%, while the rates of CD31, CD34, and HLA-DR were almost 0. The cells could differentiate into adipocytes and osteoblasts. The above results revealed that the cells cultured were human amniotic epithelial stem cells. (2) Human amniotic epithelial stem cells-derived exosomes were round or oval vesicles with diameter from 50 to 150 nm. (3) On PID 7 and 21, wound healing rates of the four groups were close (with P values above 0.05). On PID 14, wound healing rates of 50 and 100 μg/mL exosomes groups were (89.8±4.3)% and (92.0±4.6)% respectively, significantly higher than the wound healing rate of control group [(80.3±6.4)%, P<0.05 or P<0.01]. Moreover, the wound healing rate of 100 μg/mL exosomes group was significantly higher than that of 25 μg/mL exosomes group [(83.3±5.1)%, P<0.05]. On PID 21, the numbers of skin accessories in 50 and 100 μg/mL exosomes groups were 4.3±1.4 and 5.1±1.6 respectively, obviously more than those of control group and 25 μg/mL exosomes group (respectively 1.4±0.5 and 1.8±0.6, with P values below 0.01). Well reorganized collagen fibers were observed just in the healed wound tissue of 50 and 100 μg/mL exosomes groups. Conclusions: Human amniotic epithelial stem cells-derived exosomes can promote healing of wound with full-thickness skin defect in rats.

Association analysis between carcass weight and meat quality of Bamei pigs

A total of 48 crossbred Bamei pig carcasses were divided into three groups (A, 60-69 kg; B, 70-79 kg; and C, 80-90 kg) to investigate the influence of carcass weight on meat quality. The intramuscular fat content of the three groups increased from 2.20% (Group A) to 4.14% (Group C). Group B had higher drip loss (6.83%, P < 0.05) than the other two groups. Warner-Bratzler shear force decreased with increasing weight (61.16 > 51.63 > 43.64 N, P < 0.05). No significant differences were observed in meat color, cooking percentage, and water holding capacity among the three groups. The polyunsaturated fatty acids/saturated fatty acids ratio in group B (0.23) was significantly higher than that in the other two groups. In conclusion, our results suggested that a carcass weight of 70-79 kg is suitable for the production of Bamei pigs.

Comparison between meat quality of Hanzhong White pigs and carcass weight

A total of 48 carcasses of crossbred Hanzhong White pigs were divided into 3 groups (I, 90-99 kg; II, 100-109 kg; III, 110-119 kg) to investigate the influence of carcass weight on meat quality. The intramuscular fat content of the 3 groups increased from 1.90 to 4.90%; for meat color, Warner-Bratzler shear force, drip loss, and oxidation-type muscle fiber percentage, and muscle fiber diameter of the longissimus lumborum, the indices in group II and group III were better than those in group I (P < 0.05). The saturated fatty acid and polyunsaturated fatty acid percentages of the longissimus lumborum muscle (2.80 and 37.30%, respectively) in group II were significantly lower than those in the other 2 groups, while the monounsaturated fatty acid percentage was the highest (59.10%). In conclusion, our results suggest that a carcass weight of 100-109 kg is sufficient to produce acceptable meat quality of Hanzhong White pigs.

[Status analysis of patients with hypertension in 22 community health centers of Shenzhen Futian District]

OBJECTIVE

To investigate current situation of blood pressure control in patients with hypertension in 22 community health centers of Shenzhen Futian District, and to find out related factors which affect blood pressure control.

METHODS

In the study, 10 020 cases with essential hypertension that had been registered in 22 Community Health Centers were selected as cases for the survey. The questionnaires, physical examinations, and laboratory tests were used to obtain the patients' baseline data.

RESULTS

The mean blood pressure (median) levels were 142/86 mmHg (1 mmHg=0.133 kPa). Those of the males were higher than those of the females (142/86 mmHg vs. 140/85 mmHg, ZSBP=-6.14,ZDBP=-9.93,P<0.001), the systolic blood pressure increased with age. The overall blood pressure control rate was 40.2%. The blood control rates were different with different gender, body mass index (BMI) and waist circumference. The majority of the patients took single antihypertensive drug, and the proportion accounted to 54.4%. Regression analysis showed that gender, age, hyperlipidemia, smoking, and waist circumference were the main factors that affected blood pressure control.

CONCLUSION

The blood control rate was low in these communities. Patients with high blood pressure often merge a variety of factors that affect blood pressure control, and at the same time of antihypertensive therapy for the patients, we should pay attention to the control of these factors.

cDNA, genomic sequence cloning and overexpression of ribosomal protein gene L9 (rpL9) of the giant panda (Ailuropoda melanoleuca)

The ribosomal protein L9 (RPL9), a component of the large subunit of the ribosome, has an unusual structure, comprising two compact globular domains connected by an α-helix; it interacts with 23 S rRNA. To obtain information about rpL9 of Ailuropoda melanoleuca (the giant panda) we designed primers based on the known mammalian nucleotide sequence. RT-PCR and PCR strategies were employed to isolate cDNA and the rpL9 gene from A. melanoleuca; these were sequenced and analyzed. We overexpressed cDNA of the rpL9 gene in Escherichia coli BL21. The cloned cDNA fragment was 627 bp in length, containing an open reading frame of 579 bp. The deduced protein is composed of 192 amino acids, with an estimated molecular mass of 21.86 kDa and an isoelectric point of 10.36. The length of the genomic sequence is 3807 bp, including six exons and five introns. Based on alignment analysis, rpL9 has high similarity among species; we found 85% agreement of DNA and amino acid sequences with the other species that have been analyzed. Based on topology predictions, there are two N-glycosylation sites, five protein kinase C phosphorylation sites, one casein kinase II phosphorylation site, two tyrosine kinase phosphorylation sites, three N-myristoylation sites, one amidation site, and one ribosomal protein L6 signature 2 in the L9 protein of A. melanoleuca. The rpL9 gene can be readily expressed in E. coli; it fuses with the N-terminal GST-tagged protein, giving rise to the accumulation of an expected 26.51-kDa polypeptide, which is in good agreement with the predicted molecular weight. This expression product could be used for purification and further study of its function.

Relation of vision to global and regional brain MRI in multiple sclerosis

OBJECTIVE

To examine the relation between low-contrast letter acuity, an emerging visual outcome for multiple sclerosis (MS) clinical trials, and brain MRI abnormalities in an MS cohort.

METHODS

T2 lesion volume and brain parenchymal fraction were determined for whole brain and within visual pathway regions of interest. Magnetization transfer ratio histograms were examined. Vision testing was performed binocularly using low-contrast letter acuity (2.5%, 1.25% contrast) and high-contrast visual acuity (VA). Linear regression, accounting for age and disease duration, was used to assess the relation between vision and MRI measures.

RESULTS

Patients (n = 45) were aged 44 +/- 11 years, with disease duration of 5 years (range <1 to 21), Expanded Disability Status Scale score of 2.0 (0 to 6.0), and binocular Snellen acuity of 20/16 (20/12.5 to 20/25). The average T2 lesion volume was 18.5 mm(3). Patients with lower (worse) low-contrast letter acuity and high-contrast VA scores had greater T2 lesion volumes in whole brain (2.5% contrast: p = 0.004; 1.25%: p = 0.002; VA: p = 0.04), Area 17 white matter (2.5%: p < 0.001; 1.25%: p = 0.02; VA: p = 0.01), and optic radiations (2.5%: p = 0.001; 1.25%: p = 0.02; VA: p = 0.007). Within whole brain, a 3-mm(3) increase in lesion volume corresponded, on average, to a 1-line worsening of low-contrast acuity, whereas 1-line worsening of high-contrast acuity corresponded to a 5.5-mm(3) increase.

CONCLUSIONS

Low-contrast letter acuity scores correlate well with brain MRI lesion burden in multiple sclerosis (MS), supporting validity for this vision test as a candidate for clinical trials. Disease in the postgeniculate white matter is a likely contributor to visual dysfunction in MS that may be independent of acute optic neuritis history.

Autoimmune limbic encephalitis in 39 patients: immunophenotypes and outcomes

BACKGROUND

About 40% of patients with limbic encephalitis do not have detectable CNS antibodies. Some of these patients have immune-mediated limbic encephalitis, but their frequency is unknown.

AIMS

(1) To determine the spectrum of limbic encephalitis identified on clinical grounds in a single institution, and compare it with that in patients referred for antibody analysis. (2) To correlate clinical outcomes with the cellular location of the autoantigens.

METHODS

Prospective clinical case studies. Immunohistochemistry with rat brain, live hippocampal neurones, HeLa cells expressing Kv potassium channels and immunoblot.

RESULTS

In 4 years, 17 patients were identified in the Hospital of the University of Pennsylvania, Philadelphia, USA, and the serum or CSF samples of 22 patients diagnosed elsewhere were also studied. 9 of our 17 (53%) patients had antibodies to known neuronal antigens (paraneoplastic or voltage gated potassium channels (VGKCs)) and 5 (29%) to novel cell-membrane antigens (nCMAg) typically expressed in the hippocampus and sometimes in the cerebellum. Considering the entire series, 19 of 39 (49%) patients had antibodies to known antigens, and 17 (44%) to nCMAg. Follow-up (2-48 months, median 19 months) was available for 35 patients. When compared with patients with antibodies to intraneuronal antigens, a significant association with response to treatment was found in those with antibodies to cell-membrane antigens in general (VGKC or nCMAg, p = 0.003) or to nCMAg (p = 0.006).

CONCLUSIONS

(1) 82% of patients with limbic encephalitis prospectively identified on clinical grounds had CNS antibodies; (2) responsiveness to treatment is not limited to patients with VGKC antibodies; (3) in many patients (29% from a single institution), the autoantigens were unknown but were found to be highly enriched in neuronal cell membranes of the hippocampus; and (4) these antibodies are associated with a favourable outcome.

Protoplast Fusion between Geotrichum candidium and Phanerochaete chrysosporium to Produce Fusants for Corn Stover Fermentation

Lignin impedes the digestion of corn stover when used as an animal feed. Phanerochaete chrysosporium is an efficient lignindegrader. Geotrichum candidum can be used to produce single-cell protein. In this study, protoplasts of the two fungi were prepared and fused. After screening, one of the fusants, Fusant R1, was selected for corn stover fermentation. It decreased lignin from 109 to 54 g/kg and increased protein from 48 to 67 g/kg in corn stover. Comparison with their parental strains indicated that the fusant obtained the lignin-degrading ability from P. chrysosporium and the protein-accumulating ability from G. candidium.

Lymphogenous cyst-vein shunt in the management of chylothorax and chylorrhea

A 36 year-old woman developed marked lymphedema and chylous cysts of the lower abdominal wall, groin, labia, accompanied by chylorrhea. After cyst excision and transplantation of the greater omentum, a left chylothorax occurred. After thoracic duct ligation and left pleurodesis, pleural effusion recurred and worsened. Lymphangioscintigraphy and conventional lymphography suggested that undrained enlarged retroperitoneal lymphatics in the right iliac fossa had disrupted and lymph had leaked into the left chest from the right iliac fossa. Treatment by a lymphatic cyst-vein anastomosis redirected excess chylous lymph into the blood circulation and chylothorax initially remitted. Several years later with recurrence of chylorrhea, the anastomosis was found to be occluded. After a second operative connection between a lymphogenous cyst and the greater saphenous vein, chylorrhea subsided and chylothorax has remitted for more than 4 years.

Axonal damage is T cell mediated and occurs concomitantly with demyelination in mice infected with a neurotropic coronavirus

Mice infected with mouse hepatitis virus (MHV) strain JHM develop primary demyelination. Herein we show that axonal damage occurred in areas of demyelination and also in adjacent areas devoid of myelin damage. Immunodeficient MHV-infected RAG1-/- mice (mice defective in recombinase activating gene 1 expression) do not develop demyelination unless they receive splenocytes from a mouse previously immunized against MHV (G. F. Wu, A. Dandekar, L. Pewe, and S. Perlman, J. Immunol. 165:2278-2286, 2000). In the present study, we show that adoptive transfer of T cells was also required for the majority of the axonal injury observed in these animals. Both demyelination and axonal damage were apparent by 7 days posttransfer. Recent data suggest that axonal injury is a major factor in the long-term disability observed in patients with multiple sclerosis. Our data demonstrate that immune system-mediated damage to axons is also a common feature in mice with MHV-induced demyelination. Remarkably, there appeared to be a minimal, if any, interval of time between the appearance of demyelination and that of axonal injury.

Accumulation of poly-beta-hydroxybutyrate in cyanobacterium Synechocystis sp. PCC6803

Accumulation of poly-beta-hydroxybutyrate (PHB) by photoautotrophic microorganisms makes it possible to reduce the production cost of PHB. The Synechocystis sp. PCC6803 cells grown in BG11 medium under balanced, nitrogen-starved or phosphorus-starved conditions were observed by transmission electron microscope. Many electron-transparent granules in the nitrogen-starved cells had a diameter up to 0.8 micron. In contrast, the number of granules in the normally cultured cells decreased obviously and only zero to three much smaller granules were in each cell. These granules were similar to those in bacteria capable of synthesizing PHB. They were proved to be PHB by gas chromatography after subjecting the cells to methanolysis. Effects of glucose as carbon source and light intensity on PHB accumulation in Synechocystis sp. PCC6803 under nitrogen-starved cultivation were further studied. Glucose and illumination promoted cell growth but did not favor PHB synthesis. After 7 days of growth under nitrogen-starved photoautotrophic conditions, the intracellular level of PHB was up to 4.1% of cellular dry weight and the PHB concentration in the culture broth was 27 mg/l.

Selection of and evasion from cytotoxic T cell responses in the central nervous system

Cytotoxic CD8 T lymphocytes (CTLs) are critical for the clearance of noncytopathic viruses from infected cells. This chapter discusses one mechanism used by viruses to persist—namely, the selection of a variant virus in which changes in the sequence of a CTL epitope abrogate recognition. The unique features of cytotoxic CD8 T cell function in the central nervous system (CNS) are discussed. The role of CTL escape mutants in the viral evasion of the immune system and subsequent disease progression in non-CNS infections are summarized. The immune response in the CNS is similar to the response in extraneural tissue, but several aspects of the activation of the immune response, cellular trafficking, and antigen presentation are unique to the CNS. Although the CNS has classically been considered a site of immune privilege, surveillance of the normal CNS by circulating, activated lymphocytes occurs, with a limited number of lymphocytes being present in the normal CNS at any given time. In mice infected with mouse hepatitis virus and in some humans persistently infected with human immunodeficiency virus type1, hepatitis B virus or hepatitis C virus, CTL escape mutants play an important role in virus amplification and disease progression.

CD4 and CD8 T cells have redundant but not identical roles in virus-induced demyelination

A chronic demyelinating disease results from murine infection with the neurotropic strain JHM of mouse hepatitis virus (MHV-JHM). Demyelination is largely immune mediated. In this study, the individual roles of CD4 and CD8 T cells in MHV-induced demyelination were investigated using recombination-activating gene 1-/- (RAG1-/-) mice infected with an attenuated strain of MHV-JHM. These animals develop demyelination only after adoptive transfer of splenocytes from mice previously immunized to MHV. In this study, we show that, following adoptive transfer, virus-specific CD4 and CD8 T cells rapidly infiltrate the CNS of MHV-JHM-infected RAG1-/- mice. Adoptive transfer of CD4 T cell-enriched donors resulted in more severe clinical disease accompanied by less demyelination than was detected in the recipients of undepleted cells. Macrophage infiltration into the gray matter of CD4 T cell-enriched recipients was greater than that observed in mice receiving undepleted splenocytes. In contrast, CD8 T cell-enriched recipients developed delayed disease with extensive demyelination of the spinal cord. MHV-JHM-infected RAG1-/- mice receiving donors depleted of both CD4 and CD8 T cells did not develop demyelination. These results demonstrate that the development of demyelination following MHV infection may be initiated by either CD4 or CD8 T cells. Furthermore, they show that CD4 T cells contribute more prominently than CD8 T cells to the severity of clinical disease, and that this correlates with increased macrophage infiltration into the gray matter.

Coronavirus-induced demyelination occurs in the absence of inducible nitric oxide synthase

Demyelination induced by mouse hepatitis virus (MHV), strain JHM, is in large part immune mediated, but little is known about the mechanisms involved in this process. Previous results suggest that inducible nitric oxide synthase (NOS2) contributes transiently to MHV-induced demyelination. Herein, we show that equivalent amounts of demyelination were evident at day 12 after MHV infection in mice genetically deficient in NOS2 (NOS2(-/-)) and in C57BL/6 mice. Furthermore, using an established adoptive transfer model and pharmacological inhibitors of NOS2 function, we could demonstrate no effect on MHV-induced demyelination. These results indicate that NOS2 function is not required for demyelination in mice infected with MHV.

Macrophage infiltration, but not apoptosis, is correlated with immune-mediated demyelination following murine infection with a neurotropic coronavirus

Mice infected with mouse hepatitis virus strain JHM (MHV-JHM) develop a chronic demyelinating encephalomyelitis that is in large part immune mediated. Potential mechanisms of immune activity were assessed using an adoptive transfer system. Mice deficient in recombinase-activating gene function (RAG1(-/-)), defective in B- and T-cell maturation, become persistently infected with MHV but do not develop demyelination. Adoptive transfer of splenocytes from mice immunized to MHV into RAG1(-/-) mice infected with an attenuated strain of the virus results in the rapid and progressive development of demyelination. Most striking, adoptive transfer resulted, within 5 to 6 days, in extensive recruitment of activated macrophages/microglia to sites of demyelination within the spinal cord. Clearance of virus antigen occurred preferentially from the gray matter of the spinal cord. Apoptotic cells were identified in both the gray and white matter of the central nervous system (CNS) from RAG1(-/-) mice before and after adoptive transfer, with a moderate increase in number, but not distribution, of apoptotic cells following the development of demyelination. These results suggest that apoptosis following MHV-JHM infection of the murine CNS is not sufficient to cause demyelination. These results, showing that macrophage recruitment and myelin destruction occur rapidly after immune reconstitution of RAG(-/-) mice, suggest that this will be a useful system for investigating MHV-induced demyelination.

Cytotoxic T cell-resistant variants are selected in a virus-induced demyelinating disease

C57BI/6 mice infected with mouse hepatitis virus, strain JHM (MHV-JHM) develop a chronic demyelinating encephalomyelitis. Infectious virus can be isolated only from symptomatic mice. In C57BI/6 mice, two CD8+ T cell epitopes within the MHV-JHM surface glycoprotein were previously identified. Here, we show that mutations in the RNA encoding the immunodominant of the epitopes are present in nearly all virus samples isolated from these mice. Mutations are not present in sequences flanking this epitope or in other CD8+ or CD4+ T cell epitopes. Furthermore, analysis of five peptides corresponding to variant epitopes in direct ex vivo cytotoxicity assays showed that each mutation caused a loss of epitope recognition. These results suggest that escape from CD8+ T cell recognition is necessary for enhanced virus replication and development of clinical disease in these MHV-JHM-infected mice.