[Efficacy and outcomes of shunt surgery for secondary hydrocephalus].

Records of secondary hydrocephalus patients undergoing shunt surgery in the Department of Neurosurgery of Peking Union Medical College Hospital from September 2012 to April 2022 and their clinical characteristics and outcomes were retrospectively reviewed and analyzed. Among 121 patients who received first time shunt placement, the most common causes of secondary hydrocephalus were brain hemorrhage (55, 45.5%) and trauma (35, 28.9%). Cognition decline (106, 87.6%), abnormal gait (50, 41.3%) and incontinence (40, 33.1%) were the most prevalent manifestations. Postoperative central nervous system infection (4, 3.3%), shunt obstruction (3, 2.5%) and subdural hematoma/effusion (4, 3.3%) were the most frequent neurological complications. Overall incidence of postoperative complications was 9% (11 cases) in the current cohort. And 50.5% (54/107) of the patients receiving shunting achieved a Glasgow outcome scale (GOS) score of at least 4. Shunt surgery is preferred for secondary hydrocephalus, especially for secondary normal pressure hydrocephalus. Moreover, it is recommended to complete cranioplasty in staged operation or one-stage operation for the patients with decompressive craniectomy.

[Effects and mechanism of diammonium glycyrrhizinate on liver injury in severely scalded rats].

Objective: To investigate the effects and mechanism of diammonium glycyrrhizinate (DG) on liver injury in severely scalded rats. Methods: The experimental research method was used. Fifty-four female Sprague-Dawley rats aged 7-9 weeks were divided into sham injury group with simulated injury on the back, and simple scald group and scald+DG group with scald of 30% total body surface area on the back, with 18 rats in each group. Rats in sham injury group were not specially treated after injury, and rats in simple scald group and scald+DG group were rehydrated for antishock. Besides, rats in scald+DG group were injected intraperitoneally with 50 mg/kg DG at post injury hour (PIH) 1, 25, and 49. Rats in the three groups were collected, the serum content of liver function injury related indexes including aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), total protein, and albumin was measured by automatic biochemical assay analyzer, and serum content of ornithine carbamoyl transferase (OCT) was measured by enzyme-linked immunosorbent assay method at PIH 24, 48, and 72; hepatic histopathological changes at PIH 72 were observed by hematoxylin-eosin staining; the mRNA expressions of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), glucose regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), and protein kinase R-like endoplasmic reticulum kinase (PERK) in liver tissue were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction at PIH 24, 48, and 72. The protein expressions of Bcl-2, Bax, GRP78, PERK, and ATF4 in liver tissue were detected by Western blotting at PIH 72 in sham injury group and PIH 24, 48, and 72 in simple scald group and scald+DG group. The number of samples was 6 in each group at each time point. Data were statistically analyzed with analysis of variance for factorial design, one-way analysis of variance, and Bonferroni test. Results: Compared with that in sham injury group, the serum content of AST, ALT, and LDH was significantly increased (P<0.01), and the serum content of total protein and albumin was significantly decreased (P<0.05 or P<0.01) of rats in simple scald group at all post-injury time points. Compared with those in simple scald group, the serum AST content of rats in scald+DG group at PIH 24 was decreased significantly (P<0.05); the serum AST, ALT, and LDH content of rats in scald+DG group at PIH 48 was decreased significantly (P<0.01), and the serum total protein content was increased significantly (P<0.01); the serum AST, ALT, and LDH content of rats in scald+DG group at PIH 72 was decreased significantly (P<0.01), and the serum total protein and albumin content was increased significantly (P<0.01). At PIH 24, 48, and 72, the serum OCT content of rats in simple scald group was (48.5±3.9), (40.8±2.4), and (38.7±2.0) U/L, which was significantly higher than (15.1±2.5), (15.7±2.6), and (16.4±3.7) U/L in sham injury group (P<0.01), and (39.0±4.5), (31.8±2.0), and (22.1±2.6) U/L in scald+DG group (P<0.05 or P<0.01). At PIH 72, the cells in liver tissue of rats in sham injury group had normal morphology and regular arrangement, with no obvious inflammatory cell infiltration; the cells in liver tissue of rats in simple scald group had disordered arrangement, diffuse steatosis, and moderate inflammatory cell infiltration; the cells in liver tissue of rats in scald+DG group arranged regularly, with scattered steatosis and a small amount of inflammatory cell infiltration. Compared with those in sham injury group, the Bcl-2 mRNA (P<0.05 or P<0.01) and protein expressions of liver tissue were significantly decreased, and the mRNA (P<0.01) and protein expressions of Bax were significantly increased in rats in simple scald group at PIH 24, 48, and 72. Compared with those in simple scald group, the mRNA (P<0.05) and protein expressions of Bax in liver tissue of rats in scald+DG group were decreased significantly at PIH 48; the mRNA (P<0.01) and protein expressions of Bax in liver tissue of rats in scald+DG group were significantly decreased, and the mRNA (P<0.01) and protein expressions of Bcl-2 were significantly increased at PIH 72. Compared with those in sham injury group, the mRNA (P<0.05 or P<0.01) and protein expressions of ATF4, GRP78, and PERK in liver tissue were significantly increased in rats in simple scald group at all post-injury time points. Compared with those in simple scald group, the mRNA (P<0.01) and protein expressions of ATF4 in liver tissue of rats in scald+DG group at PIH 48 were significantly decreased, and the mRNA (P<0.05 or P<0.01) and protein expressions of ATF4, GRP78, and PERK were significantly decreased in liver tissue of rats in scald+DG group at PIH 72. Conclusions: DG can effectively reduce the degree of liver injury in rats after severe scald, and the mechanism may involve alleviating endoplasmic reticulum stress and mitigating mitochondrial damage.

[Effects and molecular mechanism of exogenous L-carnitine on excessive endoplasmic reticulum stress-mediated hepatic pyroptosis in severely scald rats].

Objective: To investigate the effects and molecular mechanism of exogenous L-carnitine on hepatic pyroptosis mediated by excessive endoplasmic reticulum stress in severely scald rats. Methods: The experimental research method was adopted. According to the random number table (the same group method below), fifteen female Sprague Dawley rats aged 6-8 weeks were divided into sham-injury group, scald alone group, and scald+carnitine group (with 5 rats in each group), and full-thickness scald of 30% total body surface area were made on the back of rats in scald alone group and scald+carnitine group, and rats in scald+carnitine group were additionally given intraperitoneal injection of L-carnitine. At post injury hour (PIH) 72, The levels of aspartate aminotransferase (AST) and alanine dehydrogenase (ALT) of biochemical indicators of liver injury were detected by automatic biochemical analyzer with the sample number of 5. At PIH 72, liver tissue damage was detected by hematoxylin-eosin staining. At PIH 72, The mRNA levels of nucleotide-binding oligomerization domain-containing protein-like receptor family pyrin domain containing 3 (NLRP3), cysteine aspartic acid specific protease 1 (caspase-1), gasderminD (GSDMD), and interleukin 1ß(IL-1ß) in liver tissue as pyroptosis-related markers and glucose regulatory protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP) in liver tissue as endoplasmic reticulum stress-related markers were detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction (RT-qPCR). Protein expression levels of GRP78, CHOP, NLRP3, caspase-1, caspase-1/p20, GSDMD-N, and cleaved IL-1ß in liver tissue were detected by Western blotting, and the sample numbers were all 5. HepG2 cells as human liver cancer cells were divided into dimethyl sulfoxide (DMSO) group, 0.1 µmol/L tunicamycin (TM) group, 0.2 µmol/L TM group, 0.4 µmol/L TM group, and 0.8 µmol/L TM group and were treated accordingly. After 24 h of culture, cell viability was detected by cell counting kit 8, and the intervention concentration of TM was screened, and the sample number was 5. HepG2 cells were divided into DMSO group, TM alone group, and TM+carnitine group, and treated accordingly. After 24 h of culture, the protein expression levels of GRP78, CHOP, NLRP3, caspase-1, caspase-1/p20, GSDMD-N, and cleaved IL-1ß in cells were detected by Western blotting, and the sample numbers were all 3. Data were statistically analyzed with one-way analysis of variance and least significant difference-t test. Results: At PIH 72, the AST and ALT levels of serum in scald alone group were (640±22) and (157±8) U/L, which were significantly higher than (106±13) and (42±6) U/L in sham-injury group, respectively, with t values of -46.78 and -25.98, respectively, P<0.01. The AST and ALT levels of serum in scald+carnitine group were (519±50) and (121±10) U/L, which were significantly lower than those in scald alone group, respectively, with t values of 4.93 and 6.06, respectively, P<0.01. At PIH 72, the morphology of liver tissue of rats in sham-injury group were basically normal with no obvious inflammatory cell infiltration; compared with those in sham-injury group, the liver tissue of rats in scald alone group showed a large number of inflammatory cell infiltration and disturbed cell arrangement; compared with that in scald alone group, the liver tissue of rats in scald+carnitine group showed a small amount of inflammatory cell infiltration. At PIH 72, the mRNA expression on levels of NLRP3, caspase-1, GSDMD, and IL-1ß in liver tissue of rats in scald alone group were significantly higher than those in sham-injury group (with t values of 34.42, 41.93, 30.17, and 15.68, respectively, P<0.01); the mRNA levels of NLRP3, caspase-1, GSDMD, and IL-1ß in liver tissue of rats in scald+carnitine group were significantly lower than those in scald alone group (with t values of 34.40, 37.20, 19.95, and 7.88, respectively, P<0.01). At PIH 72, the protein expression levels of NLRP3, caspase-1, caspase-1/p20, GSDMD-N, and cleaved IL-1ß in liver tissue of rats in scald alone group were significantly higher than those in sham-injury group (with t values of 12.28, 26.92, 5.20, 10.02, and 24.78, respectively, P<0.01); compared with those in scald alone group, the protein expression levels of NLRP3, caspase-1, caspase-1/p20, GSDMD-N, and cleaved IL-1ß in liver tissue of rats in scald+carnitine group were significantly decreased (with t values of 10.99, 27.96, 12.69, 8.96, and 12.27, respectively, P<0.01). At PIH 72, the mRNA levels of GRP78 and CHOP in liver tissue of rats in scald alone group were significantly higher than those in sham-injury group (with t values of 21.00 and 16.52, respectively, P<0.01), and the mRNA levels of GRP78 and CHOP in liver tissue of rats in scald+carnitine group were significantly lower than those in scald alone group (with t values of 8.92 and 8.21, respectively, P<0.01); the protein expression levels of GRP78 and CHOP in liver tissue of rats in scald alone group were significantly higher than those in sham-injury group (with t values of 22.50 and 14.29, respectively, P<0.01), and the protein expression levels of GRP78 and CHOP in liver tissue of rats in scald+carnitine group were significantly lower than those in scald alone group (with t values of 14.29 and 5.33 respectively, P<0.01). After 24 h of culture, the cell survival rates of 0.1 µmol/L TM group, 0.2 µmol/L TM group, 0.4 µmol/L TM group, and 0.8 µmol/L TM group were significantly decreased than that in DMSO group (with t values of 4.90, 9.35, 18.64, and 25.09, respectively, P<0.01). Then 0.8 µmol/L was selected as the intervention concentration of TM. After 24 h of culture, compared with that in DMSO group, the protein expression levels of GRP78 and CHOP in cells in TM alone group were significantly increased (with t values of 10.48 and 17.67, respectively, P<0.01), and the protein expression levels of GRP78 and CHOP in TM+carnitine group were significantly lower than those in TM alone group (with t values of 8.08 and 13.23, respectively, P<0.05 or P<0.01). After 24 h of culture, compared with those in DMSO group, the protein expression levels of NLRP3 and GSDMD-N in cells in TM alone group were significantly increased (with t values of 13.44 and 27.51, respectively, P<0.01), but the protein expression levels of caspase-1, caspase-1/p20, and cleaved IL-1ß in cells were not significantly changed (P>0.05); compared with that in TM alone group, the protein expression levels of NLRP3 and GSDMD-N in cells in TM+carnitine group were significantly decreased (with t values of 20.49 and 21.95, respectively, P<0.01), but the protein expression levels of caspase-1, caspase-1/p20, and cleaved IL-1ß in cells were not significantly changed (P>0.05). Conclusions: In severely scald rats, exogenous L-carnitine may play a protective role against liver injury by inhibiting the pathways related to excessive endoplasmic reticulum stress-mediated pyroptosis.

[Influence of parental compliance on the treatment of hypertrophic scars in burn children].

Objective: To explore the influence of parental compliance on the treatment of hypertrophic scars in burn children. Methods: A retrospective cohort study method was used. From June 2014 to June 2019, 49 children with post-burn hypertrophic scars who met the inclusion criteria and visited the outpatient department of the Department of Burns of the First Affiliated Hospital of Anhui Medical University were included in this study. In the follow-up of 9 months, according to the registration form and the results of the compliance questionnaire for parents, the children were divided into good compliance group (34 cases, 21 males and 13 females, aged 2.0 (2.0, 3.5) years) and poor compliance group (15 cases, 6 males and 9 females, aged 3.0 (2.0, 4.0) years). At the first attendance and in the follow-up of 3, 6, and 9 months, the scar scores of children in good compliance group were evaluated by Vancouver Scar Scale (VSS). At the first attendance and in the follow-up of 9 months, the scar scores of children in poor compliance group were evaluated by VSS. At the first attendance and in the follow-up of 9 months, the scar pruritus scores of children in the 2 groups were evaluated by Verbal Rating Score (VRS). Data was statistically analyzed with chi-square test, Wilcoxon rank sum test, Mann-Whitney U test, independent sample t test, and paired sample t test. Results: At the first attendance, the color, vascular distribution, softness, and thickness scores, and total score in VSS scoring of scars of children in the two groups were similar (Z=0.834, 0.026, 0.837, 0.076, 1.074, P>0.05). In the follow-up of 9 months, the softness and thickness scores, and total score in VSS scoring of scars of children in good compliance group were significantly lower than those in poor compliance group (Z=5.518, 4.732, 5.042, P<0.01). Compared with those in the first attendance, the color, vascular distribution, softness, and thickness scores, and total score in VSS scoring of scars of children in good compliance group were significantly decreased in the follow-up of 9 months (Z=5.241, 5.273, 5.214, 5.245, 3.451, P<0.01); the color and vascular distribution scores, and total score in VSS scoring of scars of children in poor compliance group were significantly decreased in the follow-up of 9 months (Z=3.606, 3.542, 3.448, P<0.01). At the first attendance, the VRS score of scar pruritus of children in good compliance group was 6.00 (5.00, 6.25) points, which was similar to (5.47±1.69) points in poor compliance group (Z=0.607, P>0.05). In the follow-up of 9 months, the VRS score of scar pruritus of children in good compliance group was 1.00 (1.00, 1.25) points, which was significantly lower than (3.27±1.71) points in poor compliance group (Z=2.606, P<0.01). Compared with those in the first attendance, the VRS score of scar pruritus of children in good compliance group was significantly decreased in the follow-up of 9 months (Z=4.002, P<0.01), while there was no obvious change in poor compliance group in the follow-up of 9 months (t=3.550, P>0.05). Conclusions: Under the same treatment plan, good parental compliance has a positive effect on the treatment of hypertrophic scars in burn children decreasing the degree of scar hyperplasia and pruritus.

[Effects of early supplement of exogenous L-carnitine on renal function in severely scalded rats].

Objective: To explore the effects of early exogenous L-carnitine supplementation on renal function in severely scalded rats. Methods: According to the random number table, sixty-six adult female Sprague-Dawly rats were divided into healthy control group (n=6), scald alone group (n=30), and scald+ carnitine group (n=30). In the latter two groups, the rats were inflicted with full-thickness scald of 30% total body surface area on the back, and the lactated Ringer's solution was injected through the tail vein for resuscitation immediately after scald. At post injury hour (PIH) 1, rats in scald+ carnitine group were intraperitoneally injected with 100 mg/mL L-carnitine solution 400 mg/kg, while rats in scald alone group were intraperitoneally injected with the same volume of normal saline. Rats in these two groups were injected once every 24 hours thereafter. Six rats were taken from each of scald alone group and scald+ carnitine group to collect the renal tissue and abdominal aorta blood at PIH 6, 12, 24, 48, and 72, respectively. The serum content of total protein, albumin, urea nitrogen, creatinine, and cystatin C were determined by the automatic biochemical analyzer. Renal tissue was stained with hematoxylin-eosin to observe histopathological changes. Rats in healthy control group did not undergo any treatment, and their renal tissue and blood sample were extracted and analyzed in the same way as those of severely scalded rats. Data were statistically analyzed with one-way analysis of variance and Bonferroni method. Results: (1) The serum content of total protein and albumin of rats in scald alone group at each time point after injury was significantly lower than that in healthy control group (P<0.05). The serum content of total protein of rats in scald+ carnitine group was significantly higher than that in scald alone group at PIH 12 and 24 (P<0.05), and the serum content of albumin of rats in scald+ carnitine group was significantly higher than that in scald alone group at PIH 12 (P<0.05). The serum content of total protein and albumin of rats in scald alone group and scald+ carnitine group showed a trend of decrease followed by an increase, with the lowest value at PIH 24. (2) The serum content of urea nitrogen and creatinine of rats in scald alone group at each time point after injury was significantly higher than that of healthy control group (P<0.05). The serum content of urea nitrogen of rats in scald+ carnitine group was significantly lower than that in scald alone group at PIH 6, 48, and 72 (P<0.05). The serum content of creatinine of rats in scald+ carnitine group was significantly lower than that in scald alone group at PIH 12, 24, 48, and 72 (P<0.05). The serum content of urea nitrogen and creatinine of rats in scald alone group and scald+ carnitine group showed a trend of increase followed by a decrease, with the peak value at PIH 12. (3) The serum content of cystatin C of rats in scald alone group at PIH 6, 12, 24, 48, and 72 was (0.250±0.030), (0.330±0.070), (0.300±0.060), (0.240±0.060), and (0.190±0.030) mg/L, and the content at the first 4 time points were significantly higher than (0.170±0.020) mg/L of healthy control group (P<0.05). At PIH 24, the serum content of cystatin C of rats in scald+ carnitine group was (0.210±0.040) mg/L, which was significantly lower than that of scald alone group (P<0.05). The serum content of cystatin C of rats in scald alone group and scald+ carnitine group showed a trend of increase followed by a decrease, with the peak value at PIH 12. (4) The renal tissue of rats in healthy control group was almost normal, and the degree of renal tissue injury of rats in scald+ carnitine group was lighter than that in scald alone group at each time point after injury. At PIH 24, the renal tissue of rats in scald alone group showed extensive swelling of the renal tubular epithelial cells, vacuolar degeneration and necrosis, loss of brush borders, and nuclear shrinkage; more than 2/3 of the renal tubular cell nuclei disappeared, the tubular lumen was narrowed, necrotic exfoliated cells could be seen in the lumen, and edema and inflammatory cell infiltration could be seen in the renal interstitial. Compared with those of scald alone group, significantly reduced severity of edema and necrosis of renal tubular epithelial cells, as well as less inflammatory cell infiltration were observed in the renal tissue of rats in scald+ carnitine group. Conclusions: Early supplement of L-carnitine in severely scalded rats can reduce the damage of renal cells, accelerate the restoration of the content of total protein, albumin, urea nitrogen, creatinine, and cystatin C, thereby maintaining the stability of renal function metabolism level.

Evaluation of NxTAG Respiratory Pathogen Panel and Comparison with xTAG Respiratory Viral Panel Fast v2 and Film Array Respiratory Panel for Detecting Respiratory Pathogens in Nasopharyngeal Aspirates and Swine/Avian-Origin Influenza A Subtypes in Culture Isolates.

This study evaluated a new multiplex kit, Luminex NxTAG Respiratory Pathogen Panel, for respiratory pathogens and compared it with xTAG RVP Fast v2 and FilmArray Respiratory Panel using nasopharyngeal aspirate specimens and culture isolates of different swine/avian-origin influenza A subtypes (H2N2, H5N1, H7N9, H5N6, and H9N2). NxTAG RPP gave sensitivity of 95.2%, specificity of 99.6%, PPV of 93.5%, and NPV of 99.7%. NxTAG RPP, xTAG RVP, and FilmArray RP had highly concordant performance among each other for the detection of respiratory pathogens. The mean analytic sensitivity (TCID50/ml) of NxTAG RPP, xTAG RVP, and FilmArray RP for detection of swine/avian-origin influenza A subtype isolates was 0.7, 41.8, and 0.8, respectively. All three multiplex assays correctly typed and genotyped the influenza viruses, except for NxTAG RRP that could not distinguish H3N2 from H3N2v. Further investigation should be performed if H3N2v is suspected to be the cause of disease. Sensitive and specific laboratory diagnosis of all influenza A viruses subtypes is especially essential in certain epidemic regions, such as Southeast Asia. The results of this study should help clinical laboratory professionals to be aware of the different performances of commercially available molecular multiplex RT-PCR assays that are commonly adopted in many clinical diagnostic laboratories.

Stereoselective metabolism of (±)-praeruptorin A, a calcium channel blocker from Peucedani Radix, in pooled liver microsomes of rats and humans.

(±)-Praeruptorin A (PA) is the major component of Peucedani Radix. The present study investigated stereoselectivity in PA metabolism in liver microsomes of rats (RLMs) and humans (HLMs), for the first time. PA was enantioseparated by semi-preparative chiral HPLC. Metabolic profiles of the dextrorotatory (dPA) and the levorotatory (lPA) forms in HLMs and RLMs were determined using LC-MS/MS. (-)-cis-Khellactone (D1) prepared from basic hydrolysis of dPA, and (3'R, 4'R)-4'-angeloyl-khellactone (L8) and (3'R, 4'R)-3'-angeloyl-khellactone (L9) isolated from a scale-up incubation of lPA with rat plasma were unambiguously identified by LC-MS/MS and NMR analysis. Other metabolites were tentatively identified using LC-MS/MS. In the absence of NADPH-regenerating system, dPA remained intact, however, lPA yielded L8 and L9 via a carboxylesterase(s)-mediated process. In the presence of NADPH-regenerating system, lPA produced 9 (L1-9) metabolites in both species, while dPA generated 12 (D1-12) and 6 (D1-3, 6, 9 and 10) metabolites in RLMs and HLMs, respectively. Hydrolysis, oxidation and acyl migration were demonstrated to be the predominant pathways for both enantiomers. Both enantiomers were eliminated faster in RLMs than in HLMs, while lPA showed greater species difference. PA enantiomers exhibited stereoselective metabolism in RLMs and HLMs, implying chiral discrimination in their actions.

Transport and metabolism of (±)-praeruptorin A in Caco-2 cell monolayers.

(±)-Praeruptorin A (dl-PA) is one of the main pyranocoumarins of Peucedani Radix and the chemical marker for quality control of the herb in China. This study investigated the transport and metabolism of dl-PA, for the first time, in Caco-2 cell monolayers. PA enantiomers of dl-PA in the transport study were simultaneously determined using a simple and rapid enantio-selective high performance liquid chromatography-UV method. Both dextrorotatory (d-PA) and levorotatory (l-PA) enantiomers traversed Caco-2 monolayer rapidly in both directions (absorptive P(app): 2.01-3.03 × 10(-5) cm/s; secretory P(app): 1.58-1.96 ×10(-5) cm/s) mainly via passive diffusion. Higher transport rates of dPA were observed in both directions. PA enantiomers were incompletely recovered after the transport study. Nonspecific binding to the Transwell inserts, irreversible binding to cellular components and metabolism within the cells accounted for the loss. dl-PA was partially hydrolyzed in Caco-2 monolayers and yielded two stereoisomers via removal of the acetyl group from C-4' position. Both phenylmethylsulphonyl fluoride (a nonspecific esterase inhibitor) and bis(p-nitrophenyl) phosphate sodium salt (a specific inhibitor of carboxylesterases) completely abolished dl-PA hydrolysis. In summary, PA enantiomers were rapidly transported across Caco-2 cells and partially hydrolyzed by carboxylesterases during permeation. These findings provide mechanistic understanding of in vivo pharmacokinetic properties of dl-PA.

The analgesic efficacy of continuous wound instillation with ropivacaine after open hepatic surgery.

The analgesic efficacy of continuous local anaesthetic wound instillation after open hepatic surgery was evaluated. Forty-eight patients scheduled for elective liver surgery were assigned to receive either ropivacaine 0.25% or saline infusion at 4 ml.h(-1) for 68 h via two multi-orifice indwelling catheters placed within the musculo-fascial layer before skin closure; plasma ropivacaine concentrations were measured during the infusion. Supplemental analgesia was provided by intravenous patient-controlled analgesia morphine. Patients in the ropivacaine group had decreased mean (SD) total morphine consumption (58 (30) mg vs 86 (44) mg, p = 0.01) and less pain at rest as well as after spirometry at 4, 12, 24, 48 and 72 h postoperatively (p < 0.01). Forced vital capacity was reduced postoperatively in both groups, but the reduction was greater in the saline group at 12 and 24 h (p = 0.03). The mean plasma concentration of ropivacaine increased to 2.05 (0.78) µg.ml(-1) at the point when the infusion was terminated.

A randomised controlled pilot study to compare filtration factor of a novel non-fit-tested high-efficiency particulate air (HEPA) filtering facemask with a fit-tested N95 mask.

Use of a fit-tested N95 or FFP2 mask is recommended to protect against transmission of airborne pathogens. This poses considerable logistic problems when preparing for, or dealing with, an epidemic. Some of these problems might be overcome by use of a compact reusable high-efficiency particulate air filtering mask that can be cut to size. We carried out a randomised controlled cross-over study to compare the efficacy of such a mask (Totobobo, Dream Lab One Pte Ltd, Singapore) with fit-tested N95 masks (1860 or 1860s or 1862; 3M, St Paul, MN, USA) in 22 healthy volunteers. The median (interquartile range) reduction in airborne particle counts was significantly higher [193-fold (145-200)] for N95 masks than for Totobobo masks [135-fold (83-184)] (P<0.05). There was no statistically significant difference between the proportion of subjects achieving a reduction of > or =100-fold between N95 (19/22) and Totobobo (16/22) masks. We conclude that use of the Totobobo mask without fit testing cannot be recommended, but its performance is sufficiently promising to warrant further investigation.

Force unfolding kinetics of RNA using optical tweezers. II. Modeling experiments.

By exerting mechanical force, it is possible to unfold/refold RNA molecules one at a time. In a small range of forces, an RNA molecule can hop between the folded and the unfolded state with force-dependent kinetic rates. Here, we introduce a mesoscopic model to analyze the hopping kinetics of RNA hairpins in an optical tweezers setup. The model includes different elements of the experimental setup (beads, handles, and RNA sequence) and limitations of the instrument (time lag of the force-feedback mechanism and finite bandwidth of data acquisition). We investigated the influence of the instrument on the measured hopping rates. Results from the model are in good agreement with the experiments reported in the companion article. The comparison between theory and experiments allowed us to infer the values of the intrinsic molecular rates of the RNA hairpin alone and to search for the optimal experimental conditions to do the measurements. We conclude that the longest handles and softest traps that allow detection of the folding/unfolding signal (handles approximately 5-10 Kbp and traps approximately 0.03 pN/nm) represent the best conditions to obtain the intrinsic molecular rates. The methodology and rationale presented here can be applied to other experimental setups and other molecules.

Protecting staff against airborne viral particles: in vivo efficiency of laser masks.

Laser masks are used to prevent inhalation of viral particles during laser surgery. A crossover trial was performed in eight volunteers to compare the ability of a surgical mask and a laser mask with that of an FFP2 respirator to filter airborne dust particles. The surgical and laser masks were tested when worn normally and when they were taped to the face. The mean reductions in particle counts were 3.0 fold [95% confidence interval (95% CI) 1.8-4.2] for the untaped surgical mask, 3.8 fold (95% CI 2.9-4.6) for the untaped laser mask, 7.5 fold (95% CI 6.5-8.5) for the taped surgical mask, 15.6 fold (95% CI 13.5-17.8) for the taped laser mask, and 102.6 fold (95% CI 41.2-164.1) for the FFP2 half-face respirator. The laser mask provided significantly less protection than the FFP2 respirator (P=0.02), and only marginally more protection than the surgical mask. The continued use of laser masks for respiratory protection is questionable. Taping masks to the face only provided a small improvement in protection.

The effect of force on thermodynamics and kinetics: unfolding single RNA molecules.

We have used laser tweezers to unfold single RNA molecules at room temperature and in physiological-type solvents. The forces necessary to unfold the RNAs are over the range 10-20 pN, forces that can be generated by cellular enzymes. The Gibbs free energy for the unfolding of TAR (transactivation-responsive) RNA from HIV was found to be increased after the addition of argininamide; the TAR hairpin was stabilized. The rate of unfolding was decreased and the rate of folding was increased by argininamide.

[A simplified method for detection of genomic subtyps of HBV S-gene].

When the 513 bp amplified fragments of HBV S-gene, known subtypes, were digested with Msp I and BamH I, the following phenomena appeared: adr subtypic 513 bp was fragmentized to 320 bp and 193 bp by Msp I; ayw subtype was digested and fragmentized to 295 bp and 218 bp by BamH I; ayw could also be fragmentized to become 326 bp and 187 bp digested by Msp I. Howerev, adw subtype was not digested by Msp I and BamH I nor adr by BamH I. The experimental patterns in agarose gel electrophoresis were tallied with the expected patterns. Each HBV subtypes gave unique size of digestive fragments which was easy to observe and distinguish on agarose gel. This study provided a new classification scheme for HBV-DNA and could be used for epidemiological investigation of HBV infection.