[Application of cold flowable gutta-percha in root canal obturation after apexification].

OBJECTIVE: To evaluate the clinical effect of root canal obturation therapy using cold flowable gutta-percha on young permanent teeth after apexification. METHODS: Ninety cases of young permanent teeth with pulp necrosis or periapical periodontitis treated by apexification were randomly divided into two groups. The cases in each group were divided into single root canal and multiple root canal according to the number of the root canal, and divided into classifications Ⅰ, and Ⅱ/Ⅲ/Ⅳ according to Frank's classification of root development after apexification. Cold flowable gutta-percha and warm gutta-percha obturation techniques were used for root canal obturation of the two groups. The operation time was recorded, and the patients' therapy pain degree was evaluated by visual analog scale (VAS) immediately after operation. Periapical X-ray was performed after operation to evaluate the effect of the root canal filling. The total length of the root was divided into equal three parts on the X-ray film, and three-dimensional tightness of the apical, middle, and coronal region of the root canals were statistically analyzed respectively. Clinical examinations and X-ray examination were performed 6 and 12 months after the operation to evaluate the treatment success rate. RESULTS: The operation time of cold flowable gutta-percha group was significantly lower than that of the control group, which were 51 s and 74 s (P < 0.05); The percentages of pain and discomfort in the two groups were 26.67% and 40.00%, respectively. There were two cases of underfilling and no overfilling in both groups. The percentages of proper filling and tight three-dimensional obturation in the experimental and control groups were 71.11% and 60.00% respectively; and the percentages of tight three-dimensional obturation in the apical third areas were 86.67% and 66.67%, the difference was significant (P < 0.05). There was no significant difference in the three-dimensional tightness between the two groups in the middle and coronal third areas. The percentages of tight three-dimensional obturation in classification Ⅰ groups were 86.67%, 83.33%, 93.33% and 76.67%, 90.00%, 96.67% in experimental and control group, respectively; The percentages of classification Ⅱ/Ⅲ/Ⅳ groups were 86.67%, 86.67%, 100.00% and 46.67%, 86.67%, 100.00%, respectively, and the difference was significant (P < 0.05). There were no apical lesions that occurred in either group during the one-year review period. CONCLUSION: The application of cold flowable gutta-percha on young permanent teeth root canal obturation after apexification can achieve good obturation effect. The root obturation effect in the apical third area is significantly better than that of warm gutta-percha obturation techniques. Cold flowable gutta-percha can shorten the clinical treatment time and ameliorate the patients' therapy comfort.

The importance of mRNA structure in determining the pathogenicity of synonymous and non-synonymous mutations in haemophilia.

INTRODUCTION: Mutational analysis is commonly used to support the diagnosis and management of haemophilia. This has allowed for the generation of large mutation databases which provide unparalleled insight into genotype-phenotype relationships. Haemophilia is associated with inversions, deletions, insertions, nonsense and missense mutations. Both synonymous and non-synonymous mutations influence the base pairing of messenger RNA (mRNA), which can alter mRNA structure, cellular half-life and ribosome processivity/elongation. However, the role of mRNA structure in determining the pathogenicity of point mutations in haemophilia has not been evaluated. AIM: To evaluate mRNA thermodynamic stability and associated RNA prediction software as a means to distinguish between neutral and disease-associated mutations in haemophilia. METHODS: Five mRNA structure prediction software programs were used to assess the thermodynamic stability of mRNA fragments carrying neutral vs. disease-associated and synonymous vs. non-synonymous point mutations in F8, F9 and a third X-linked gene, DMD (dystrophin). RESULTS: In F8 and DMD, disease-associated mutations tend to occur in more structurally stable mRNA regions, represented by lower MFE (minimum free energy) levels. In comparing multiple software packages for mRNA structure prediction, a 101-151 nucleotide fragment length appears to be a feasible range for structuring future studies. CONCLUSION: mRNA thermodynamic stability is one predictive characteristic, which when combined with other RNA and protein features, may offer significant insight when screening sequencing data for novel disease-associated mutations. Our results also suggest potential utility in evaluating the mRNA thermodynamic stability profile of a gene when determining the viability of interchanging codons for biological and therapeutic applications.

Improved carrier injection in GaN-based VCSEL via AlGaN/GaN multiple quantum barrier electron blocking layer.

In this report, the improved lasing performance of the III-nitride based vertical-cavity surface-emitting laser (VCSEL) has been demonstrated by replacing the bulk AlGaN electron blocking layer (EBL) in the conventional VCSEL structure with an AlGaN/GaN multiple quantum barrier (MQB) EBL. The output power can be enhanced up to three times from 0.3 mW to 0.9 mW. In addition, the threshold current density of the fabricated device with the MQB-EBL was reduced from 12 kA/cm2 (9.5 mA) to 10.6 kA/cm2 (8.5 mA) compared with the use of the bulk AlGaN EBL. Theoretical calculation results suggest that the improved carrier injection efficiency can be mainly attributed to the partial release of the strain and the effect of quantum interference by using the MQB structure, hence increasing the effective barrier height of the conduction band.

Predictive factors for early failure of transarterial embolization in blunt hepatic injury patients.

AIM: To evaluate the early success of transarterial embolization (TAE) in patients with traumatic liver haemorrhage and to determine independent factors for its failure. MATERIALS AND METHODS: From January 2009 to December 2012, TAE was performed in 48 patients for traumatic liver haemorrhage. Their medical charts were reviewed for demographic information, pre-TAE vital signs and laboratory data, injury grade, type of contrast medium extravasation (CME) at CT, angiography findings, and early failure. "Early failure" was defined as the need for repeated TAE or a laparotomy for hepatic haemorrhage within 4 days after TAE. Variables were compared between the early success and early failure groups. Variables with univariate significance were also analysed using multivariate logistic regression for predictors of early failure. RESULTS: Among 48 liver TAE cases, nine (18.8%) were early failures due to liver haemorrhage. Early failure was associated with injury grade (p = 0.039), major liver injury (grades 4 and 5; p = 0.007), multiple CMEs at angiography (p = 0.031), incomplete TAE (p = 0.002), and elevated heart rate (p = 0.026). Incomplete embolization (OR = 8; p = 0.042), and heart rate >110 beats/min (bpm; OR = 8; p = 0.05) were independent factors for early failure of TAE in the group with major liver injuries. CONCLUSION: Major hepatic injury is an important factor in early failure. Patients with a heart rate >110 bpm and incomplete embolization in the major injury group have an increased rate of early failure. The success rate of proximal TAE was comparable to that of the more time-consuming, superselective, distal TAE.

[Management and prognosis of extremely preterm infants with gestational age ≤25+6 weeks].

Objective: To investigate the outcomes including major complications and prognosis of extremely preterm infants with gestational age ≤25+6 weeks. Methods: The cross-sectional study enrolled 233 extremely preterm infants with gestational age ≤25+6 weeks who were admitted to the Department of Neonatology of Shenzhen Maternity and Child Healthcare Hospital from January 2015 to December 2021. The clinical data including perinatal factors, treatments, complications, and prognosis were extracted and analyzed. These extremely preterm infants were also grouped according to gestational age and year of admission to further analyze their survival rate, major complications, causes of death, and long-term outcomes. The comparisons between the groups were performed with Chi-square test and Kruskal-Wallis. Results: Among these 233 extremely preterm infants, 134 (57.5%) were males and 99 (42.5%) females. The gestational age was (24.6±0.9) weeks, the birth weight was 710.0 (605.0,784.5) g, and the overall survival rate was 61.8% (144/233). Among the surviving extremely preterm infants, the earliest gestational age was 22+2 weeks and the lowest birth weight was 390 g. There were 17.6% (41/233) of extremely preterm infants had treatment withdrawn and were discharged in line with the will of guardians. Among the rest 192 extremely preterm infants managed with aggressive treatments, 14 (7.3%) died in hospital and 34 (17.7%) had treatment withdrawn later due to severe complications. Of the 192 extremely preterm infants, 144 (75.0%) survived, and the survival rate increased year by year (χ2=26.28, P<0.001) while the mortality decreased year by year (χ2=14.09, P=0.027). Among the survivors, 20.8%(30/144) had no major complications, and the incidence of complications was also negatively related with the gestational age (χ2=7.24, P=0.044), and the length of invasive ventilation was negatively related to the gestational age (χ2=29.14, P<0.001). In the group of less than 23+6 weeks, all extremely preterm infants had one or more major complications. The follow-up were completed in 122 infants and revealed that delayed motor development, language retardation, and hearing and vision impairment accounted for 17.2% (21/122), 8.2% (10/122) and 17.2% (21/122), respectively. Conclusions: Extremely preterm infants with gestational age ≤25+6 weeks are difficult to treat, but the survival rate of infants undergoing aggressive treatments increases year by year. Although the prevalence of major complications is still high, most extremely preterm infants have acceptable prognosis during follow-up.

Computed tomography in left-sided and right-sided blunt diaphragmatic rupture: experience with 43 patients.

AIM: To investigate differences in the radiographic signs for left and right-sided blunt diaphragmatic rupture (BDR) in order to provide guidance to avoid missing these injuries. MATERIALS AND METHODS: A retrospective review of the computed tomography (CT) examinations of 43 patients with BDR treated at our hospital between January 1995 and 2007 was undertaken. The presence of diaphragmatic discontinuity, diaphragmatic thickening, herniation of abdominal organs into the thoracic cavity, collar/hump sign, dependent viscera sign, abnormally elevated 4 cm or more above the dome of the other-sided hemi-diaphragm, and of associated injuries was recorded and their relationship to each other and to BDR diagnosis examined. A comparison between the use of axial and sagittal/coronal reconstruction images in diagnosis was also performed in 15 patients. RESULTS: On axial imaging, left-sided diaphragmatic rupture occurred in 31 patients (72%) and right-sided in 12 (28%). Twenty-nine patients had associated injuries. More than 60% of the patients showed the "dependent viscera" sign, "abdominal organ herniation" sign, diaphragm thickening, or had a more than 4 cm elevation of one side of the diaphragm. "Diaphragmatic discontinuity" and "stomach herniation" were seen almost exclusively in left-sided rupture. Those with BDR and haemothorax had a significantly lower incidence of "diaphragm discontinuity" (p=0.034) than those without haemothorax. Sagittal/coronal reconstruction slightly increased the number of band signs, diaphragmatic discontinuities and diaphragmatic thickenings seen. CONCLUSIONS: Of the CT signs examined in this study, when herniation of abdominal organs was used as a diagnostic marker, only a very small fraction of trauma patients identifiable by CT would be missed. Further, CT signs differ for left-sided and right-sided BDR, thus the possibility of BDR should be considered when any of the reported CT signs are present.

[Post-discharge growth of extremely premature infants within corrected age of 24 months].

Objective: To demonstrate the post-discharge catch-up growth of extremely premature infants (EPI) within 24 months of corrected age. Methods: This study retrospectively collected the anthropomorphic measurements of 311 EPI who visited Shenzhen Maternity and Child Healthcare Hospital from August 2013 to April 2020. These infants were stratified according to gestational age at birth (GA): 23-24+6weeks, 25-26+6weeks, 27-27+6weeks; and birth weight:<750 g, 750-999 g, ≥1 000 g. The anthropomorphic measurements, including weight, length, and head circumference for age, were recorded timely from discharge to 24 months of corrected age. And the growth curve stratified by GA and birth weight were fitted in both chronological age and corrected age, which were then compared with the World Health Organization Child Growth Standards for term infant (2006 version), to investigate the catch-up growth pattern of EPI. And appropriate catch-up was defined as the measurements reached the 25th percentile of WHO growth curve. Results: In these 311 EPI, 184 were males and 127 females, with gestational age of 23-27+6 weeks and birth weight of 480-1 430 g. Regardless of the GA and birth weight, the growth curves fitted in corrected age failed to overlap with that in chronological age by 24 months of corrected age. The growth velocity of weight, length and head circumference in both corrected and chronological age were all positively correlated with GA and birth weight: the 27-27+6weeks group showed a preferable growth pattern than the 25-26+6weeks group, and the curve of the 23-24+6weeks group was most unfavorable; and the same pattern was observed between the subgroups of different birth weight. Furthermore, the GA had more significant impact on the catch-up growth pattern than birth weight did. When assessed with corrected age curve, the weight and length of both male and female EPIs achieved appropriate catch-up by 24 months, as well as the head circumference of girls; whereas, boys' head circumference reached appropriate catch-up at the corrected age of 9 months, but fell behind the 25th percentile after that. However, when assessed with chronological age curve, both boys and girls failed to achieve appropriate catch-up in weight, length and head circumference by age 24 months. And no matter in corrected or chronological age, all physical measurements of girls were lower than those of boys. Conclusions: The rapid catch-up growth of EPI happens within 6 months of corrected age. The lower the birth weight and gestational age, the lower the physical measurements at each corresponding month of age, and the longer it takes to achieve appropriate catch-up. Gestational age has a greater impact on the longitudinal catch-up growth than birth weight does. And girls generally grow slower than boys in either correct or actual age. Before 24 months of corrected age, the growth should be assessed with corrected age rather than chronological age.

[Risk factors and prognosis of bronchopulmonary dysplasia associated pulmonary hypertension in preterm infants].

Objective: To analyze clinical features, prognosis and risk factors of bronchopulmonary dysplasia (BPD) associated pulmonary hypertension (PH). Methods: Clinical data of 338 infants with BPD were collected from the neonatal intensive care unit (NICU) in Shenzhen Maternity and Child Healthcare Hospital, Southern Medical University between January 2016 and December 2018. These infants were divided into PH group and non-PH group. The clinical features and prognosis were compared between these two groups by Chi-square test or nonparametric test. Risk factors for BPD-PH were analyzed with binary logistic regression model. Results: Among the 338 BPD infants, 314 had no PH (92.9%) and 24 had PH (7.1%), with an average gestational age of (27.1±1.8) weeks, and 206 were males and 132 females.PH infants had younger gestational age ((26.4±2.1) vs. (27.2±1.7) weeks, t=2.201, P=0.028) and lower birth weight ((798±255) vs. (1 003±240) g, t=4.030, P<0.01), compared to non-PH infants. Besides, duration of mechanical ventilation and non-invasive positive pressure ventilation were higher in PH group than that in non-PH group (14.3 (2.1, 43.7) vs. 0.5 (0, 4.7) d, Z=-4.553, P<0.01; 30.0 (22.5, 64.2) vs. 15.0 (7.0, 26.0) d, Z=-4.838, P<0.01). The proportions of maternal hypertension, small for gestational age (SGA), late onset sepsis, ventilator associated pneumonia, hemodynamically significant patent ductus arteriosus (hsPDA), patent ductus arteriosus (PDA) requiring ligation, severe BPD and severe extrauterine growth retardation (EUGR) were higher in PH group than those in non-PH group ((20.8% (5/24) vs. 6.4% (20/314), 33.3% (8/24) vs. 7.6% (24/314), 54.2% (13/24) vs. 7.3% (23/314), 25.0% (6/24) vs. 6.1% (19/314), 75.0% (18/24) vs. 39.2% (123/314), 45.8% (11/24) vs. 1.9% (6/314), 66.7% (16/24) vs. 7.3% (23/314), 75.0% (18/24) vs. 45.5% (143/314), all P<0.05). Multivariate logistic regression analysis showed that maternal hypertension (OR=12.950, 95%CI: 1.740-96.385), severe bronchopulmonary dysplasia (OR=10.160, 95%CI: 2.725-37.884), SGA (OR=4.992, 95%CI: 1.432-16.920), PDA requiring ligation (OR=19.802, 95%CI: 3.297-118.921), severe EUGR (OR=20.316, 95%CI: 2.221-185.853) were independent risk factors of BPD associated PH. In the 24 infants with PH, all 7 mild PH infants and 8 moderate PH infants survived, while 4 out of 9 severe PH infants died. Among the survivors, the longest duration of oxygen therapy was up to the corrected gestational age of 1 year and 2 months. Conclusions: PH is a severe complication of BPD, and associated with higher mortality and poor prognosis. Echocardiography screening and regular post-discharge follow up are recommended for BPD infants with risk factors of PH.

Correlation between miR-1207-5p expression with steroid-induced necrosis of femoral head and VEGF expression.

OBJECTIVE: The aim of this study was to investigate the expression level of micro-ribonucleic acid-1207-5p (miR-1207-5p) in steroid-induced necrosis of femoral head (SNFH) and its correlation with SNFH. Meanwhile, we also aimed to analyze the relationship between miR-1207-5p expression and vascular endothelial growth factor (VEGF) in the femoral head. PATIENTS AND METHODS: From May 2016 to December 2017, 60 patients aged (55.4±8.7) were selected in our hospital. All patients were diagnosed and confirmed as SNFH. Total RNA was extracted from the necrotic femoral head tissues and peripheral blood. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was used to detect the expression level of miR-1207-5p in tissues. At the same time, immunohistochemistry and Western blotting were adopted to detect VEGF expression in the bone tissue of patients with high or low expression of miR-1207-5p. 7 patients with femoral neck fracture aged (45.6±4.51) were enrolled in the control group. In the animal experiment, the rat SNFH model was established by intraperitoneal injection of lipopolysaccharide and methylprednisolone. Subsequently, the expression levels of miR-1207-5p and VEGF in necrotic femoral tissues were detected. Meanwhile, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was applied to detect cell apoptosis in bone lacunae of miR-1207-5p high expression group and miR-1207-5p low expression group, respectively. RESULTS: The expression level of miR-1207-5p in the necrotic bone tissue of the SNFH group was significantly higher than that of the control group. The expression level of miR-1207-5p was inversely proportional to Harris Hip score (p<0.05). A higher expression of miR-1207-5p indicated a lower expression level of VEGF (p<0.05). The animal experimental results revealed that miR-1207-5p expression in the necrotic femoral head tissue of SNFH group was significantly higher than that of the control group. Furthermore, the number of apoptotic cells in bone lacunae was remarkably higher in miR-1207-5p high expression group (p<0.05). CONCLUSIONS: MiR-1207-5p is significantly up-regulated in necrotic femoral head tissue and serum of SNFH patients. Meanwhile, its expression level is inversely proportional to Harris Hip score of patients. The possible underlying mechanism may be related to the inhibitory effect of miR-1207-5p on VEGF.

Spleen-preserving versus spleen-sacrificing distal pancreatectomy in adults with blunt major pancreatic injury.

BACKGROUND: The aim of this study was to analyse outcomes of spleen-preserving (SPDP) and spleen-sacrificing (SSDP) distal pancreatectomy in adults with severe blunt pancreatic injuries. METHODS: This was an observational study of adult patients who underwent distal pancreatectomy for grade III or IV blunt pancreatic injury between 1991 and 2015. Outcomes of SPDP and SSDP were compared. RESULTS: Fifty-one patients were included, of whom 23 underwent SPDP and 28 SSDP. The median Injury Severity Score (ISS) was 13·0 (i.q.r. 9·0-18·0). No significant differences were observed between the groups regarding sex, trauma mechanism, shock at triage, laboratory data, location, ISS, associated injury, length of stay, mortality or morbidity. Age (27·0 versus 36·5 years; P = 0·012) and time interval from injury to distal pancreatectomy (15·0 versus 44·0 h; P = 0·022) differed significantly between SPDP and SSDP groups respectively. The mortality rate was 4 per cent (1 of 23) versus 11 per cent (3 of 28) respectively (P = 0·617). Nine patients (39 per cent) developed abdominal morbidity after SPDP, compared with 17 (61 per cent) after SSPD (P = 0·125). In the SPDP group, eight patients had grade B postoperative pancreatic fistula (POPF), two of whom required further intervention. In the SSDP group, six of ten patients with grade B POPF required CT-guided drainage, and a further five patients required reoperation for other causes. There were more reinterventions after SSDP: 11 of 28 (39 per cent) versus 3 of 23 (13 per cent) in the SPDP group (P = 0·037). CONCLUSION: SPDP was performed more often in younger patients and at a shorter interval after severe blunt pancreatic injury. SPDP was associated with fewer reinterventions.

Glycosylation and surface expression of the influenza virus neuraminidase requires the N-terminal hydrophobic region.

A full-length double-stranded DNA copy of an influenza A virus N2 neuraminidase (NA) gene was cloned into the late region of pSV2330, a hybrid expression vector that includes pBR322 plasmid DNA sequences and the simian virus 40 early region and simian virus 40 late region promoters, splice sequences, and transcription termination sites. The protein encoded by the cloned wild-type NA gene was shown to be present in the cytoplasm of fixed cells and at the surface of "live" or unfixed cells by indirect immunofluorescence with N2 monoclonal antibodies. Immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of [35S]methionine-labeled proteins from wild-type vector-infected cells with heterospecific N2 antibody showed that the product of the cloned NA DNA comigrated with glycosylated NA from influenza virus-infected cells, remained associated with internal membranes of cells fractionated into membrane and cytoplasmic fractions, and could form an immunoprecipitable dimer. NA enzymatic activity was detectable after simian virus 40 lysis of vector-infected cells. These properties of the product of the cloned wild-type gene were compared with those of the polypeptides produced by three deletion mutant NA DNAs that were also cloned into the late region of the pSV2330 vector. These mutants lacked 7 (dlk), 21 (dlI), or all 23 amino acids (dlZ) of the amino (N)-terminal variable hydrophobic region that anchors the mature wild-type NA tetrameric structure in the infected cell or influenza viral membrane. Comparison of the phenotypes of these mutants showed that this region in the NA molecule also includes sequences that control translocation of the nascent polypeptide into membrane organelles for glycosylation.

A conformational switch in nuclear hormone receptors is involved in coupling hormone binding to corepressor release.

Nuclear hormone receptors are ligand-regulated transcription factors that modulate gene expression in response to small, hydrophobic hormones, such as retinoic acid and thyroid hormone. The thyroid hormone and retinoic acid receptors typically repress transcription in the absence of hormone and activate it in the presence of hormone. Transcriptional repression is mediated, in part, through the ability of these receptors to physically associate with ancillary polypeptides called corepressors. We wished to understand the mechanism by which corepressors are recruited to unliganded nuclear hormone receptors and are released on the binding of hormone. We report here that an alpha-helical domain located at the thyroid hormone receptor C terminus appears to undergo a hormone-induced conformational change required for release of corepressor and that amino acid substitutions that abrogate this conformational change can impair or prevent corepressor release. In contrast, retinoid X receptors appear neither to undergo an equivalent conformational alteration in their C termini nor to release corepressor in response to cognate hormone, consistent with the distinct transcriptional regulatory properties displayed by this class of receptors.

Long-term results of endoscopic stent in the management of blunt major pancreatic duct injury.

BACKGROUND: Pancreatic stents can be used to treat a variety of acute and chronic pancreatic lesions. Sporadic successful trials in trauma patients have been reported. To our knowledge, however, a series with long-term follow-up has not previously been reported. We treated six patients in a 6-year period and report the long-term results. METHODS: From February 1999 to February 2005, six blunt-trauma patients with major pancreatic duct disruption were treated with pancreatic duct stent at a single trauma center. Assessment of injury severity and diagnosis were based on abdominal computed tomography (CT) and proved by endoscopic retrograde pancreatography (ERP), with chart review used to establish mechanism of injury, timing of ERP, and stent placement, as well as the long-term outcome. RESULTS: Three of the six injuries were classified AAST grade III and three were grade IV; the interval to ERP with stent placement ranged from 8 hours to 22 days after the injury. One patient developed sepsis and died. One patient's stent could be removed early (52 days post-stenting) with mild ductal stricture, whereas the other four were complicated by severe ductal stricture that required repeated and prolonged stenting treatment. Removal of the stents was only possible in three of these four cases (at 12, 19, and 39 months, respectively), with stent dislodgment in the pancreatic duct occurring in another. CONCLUSIONS: Stent therapy may avoid surgery in the acute trauma stage, and may be preserved as another choice for acute grade IV pancreatic injury. However, variant outcome and long-term ductal stricture reveal that the role of pancreatic duct stent is uncertain and may not be suitable for acute grade III pancreatic injury. However, it needs more clinical data to define the value in the acute blunt pancreatic duct injury.

Comparison of selective arginine vasopressin V1 and V2 receptor antagonists on burn shock in the rat.

STUDY OBJECTIVE: Two selective V1 and V2 receptor antagonists of arginine vasopressin, d(CH2)5Tyr(Me)AVP and d(CH2)5[D-Ile2, Ile4, Ala9-NH2]AVP, were given intravenously in burn shocked rats to investigate the respective effects of V1 and V2 receptor blockade on the haemodynamic variables in burn shock. DESIGN: Computer assisted on line real time measurements of mean arterial blood pressure, diastolic blood pressure, left ventricular systolic pressure, dP/dtmax, and heart rate were used to study the effects of the receptor antagonists during burn shock. In addition, the radioactive microsphere method was used to measure the changes of cardiac output and regional blood flows to heart, kidney, and liver in response to the antagonists during burn shock. Third degree burns extending over 30% of body surface area were made by dipping the rat's shaved back into water at 100 degrees C for 20 s. EXPERIMENTAL MATERIAL: Male Sprague-Dawley rats (250-300 g) were used in groups of 6-9 per experiment. MEASUREMENTS AND MAIN RESULTS: Mean and diastolic arterial blood pressures, left ventricular systolic pressure, dP/dtmax and heart rate were measured for 8 h after burns. Cardiac output and regional blood flow were measured at 3 h and 8 h postburn. Results showed that blockade of V1 receptor lowered mean and diastolic arterial blood pressures throughout the 8 h period, and raised left ventricular systolic pressure and dP/dtmax only during the early phase of shock. Cardiac output and blood flows to heart, kidney, and liver were increased by the V1 antagonist at 3 h but not at 8 h postburn. The V2 receptor antagonist increased mean and diastolic arterial blood pressures, left ventricular systolic pressure, and dP/dtmax both during the early and during the late phases of burn shock. It also improved cardiac output and blood flows to the heart, kidney, and liver during the early and late phases of burn shock. However, heart rate was not affected by V1 and V2 receptor antagonists. CONCLUSIONS: The V2 like receptor may be the dominating receptor mediating vasopressin's inhibitory effect on the heart. V1 receptor mediated coronary vasoconstriction contributes to the myocardial depression possibly only at the compensatory phase of shock. In addition V1 receptor mediated vasoconstriction is important in maintaining blood pressure during burn shock.

Dynorphin A enhances mitogen-induced proliferative response and interleukin-2 production of rat splenocytes.

It has been well known that immune function is modulated by endogenous opioid peptides: beta-endorphin and enkephalins. However, the effect of dynorphin A on the immune function has not been well documented. In this study, we investigated dynorphin A in the regulation of mitogen-induced proliferation and and interleukin-2 (IL-2) production of rat splenocytes. The results showed that dynorphin A 1-13 as well as dynorphin A 1-17 enhanced concanavalin A-stimulated [(3)H] thymidine uptake 46-112% and IL-2 production in a dose-dependent fashion. These effects were reversed by naloxone and norBNI, a selective kappa-receptor antagonist. Dynorphin A reduced cyclic AMP contents in spenocytes in naloxone and norBNI reversible fashion. The data suggest that dynorphin A enhanced mitogen-stumulated lymphocyte proliferation and IL-2 production via kappa-opioid receptor and cAMP pathway.

Effect of peripheral injection of arginine vasopressin and its receptor antagonist on burn shock in the rat.

To investigate the effect of arginine vasopressin (AVP) in the peripheral circulation on burn shock in the rat, AVP and its nonselective V1/V2 receptor antagonist d(CH2)5Tyr (Et)VAVP were administered intravenously in burn shocked rats. Cardiovascular parameters were recorded including left ventricular systolic pressure (LVSP), +/- dP/dt max, total area of the cardiac force loop (Lo), mean arterial blood pressure (MAP), heart rate (HR) and electrocardiogram (ECG). Our results showed that AVP failed to increase MAP in burned rats whereas it elicited a greater fall in LVSP, +/- dP/dt max and Lo and MAP than seen in control burned rats and hastened the onset of the decompensatory phase of burn shock resulting in the early death of burn shocked animals. The receptor antagonist d(CH2)5Tyr(Et)VAVP elevated LVSP, +/- dp/dt max and Lo for the eight hour observation period, and allowed MAP to recover from the initial profound fall following burn injury. Furthermore, it prolonged the survival time of the burned rats. AVP treated rats also displayed earlier abnormal changes such as elevation of S-T segment, inversion of T wave and ventricular fibrillation in ECG. The onset of these changes was much delayed in antagonist treated rats.

Pooling of contrast material on computed tomography mandates aggressive management of blunt hepatic injury.

BACKGROUND: Nonoperative management of blunt hepatic injury is currently a widely accepted treatment modality. Computed tomography (CT) is an important imaging study both for diagnosis and follow-up of these patients. There is, however, no reliable predictor of failure of nonoperative treatment other than the ultimate development of hemodynamic instability. Previous reports mostly were based on the data obtained from low-speed dynamic incremental scanners. The purpose of this study is to evaluate the value of a high-speed helical scanner in predicting the outcome of patients managed nonoperatively. METHODS: During a 30-month period, 194 patients with blunt hepatic injury were treated, 150 of them were hemodynamically stable after initial resuscitation and underwent abdominal CT examination. All CT scans were performed with the High Speed Advantage Scanner. The CT scans and medical records were reviewed. RESULTS: Nonoperative management was successfully applied to all patients with grade I and II, 93% of grade III, 87% of grade IV, and 67% of grade V liver injuries. Twelve patients required liver-related celiotomy. Pooling of contrast material was detected on the CT scans of 8 patients. Six (75%) of these patients developed hemodynamic instability and required liver-related celiotomy later. Pooling of contrast material can be detected in 50% of the patients receiving liver-related celiotomy. CONCLUSION: The presence of pooling of contrast material within the hepatic parenchyma indicates free extravasation of blood as a result of active bleeding. In patients with blunt hepatic injury, if this sign is detected, nonoperative treatment should be terminated and angiography or celiotomy undertaken promptly. With the increasing use of high-speed spiral CT scanner and improvement in scanning technique, pooling of contrast material may become a sensitive sign for active bleeding and may be used as a guide for the selection of treatment modality.

Blood glucose measurement by multiple attenuated total reflection and infrared absorption spectroscopy.

The difficulty of measuring physiological concentrations of glucose in blood by conventional infrared absorption spectroscopy is due to the intrinsic high background absorption of water. This limitation can be largely overcome by the use of a CO2 laser as an infrared source in combination with a multiple attenuated total reflection (ATR) technique. To demonstrate the applicability of this technique, we compared in vitro measurements of glucose in blood obtained from an experimental infrared laser spectrometer with independent measurements made by a standard YSI 23A laboratory glucose analyzer. The capability of continuous measurement of blood glucose concentration is of primary importance in the future development of a glucose sensor for diabetic patients.

Nonlinear chromatography Recent theoretical and experimental results.

The theory of nonlinear chromatography has been advanced by the incorporation of recent results obtained by the theory of partial differential equations. The system of equations of the ideal model has been solved analytically in the case of a single component for which the equilibrium isotherm between the mobile and the stationary phases is given by a Langmuir equation. A series of computer programs has been written which permits the calculation of numerical solutions of the semi-ideal model. The properties of the solutions obtained are described and discussed for a one-component system (profile of high concentration bands of a pure compound eluted by a pure solvent), several two-component systems (elution of a pure compound band by a binary mobile phase, separation of a binary mixture eluted by a pure mobile phase), and three-component systems (separation of a binary mixture eluted by a binary solvent, displacement and separation of a binary mixture). Experimental results are reported which validate the conclusions derived from the numerical integration of the model. The conclusions of the work apply to all high-performance chromatographic procedures, i.e., to those where the kinetics of mass transfer are fast enough for the mobile and stationary phases always to be near equilibrium. More specifically, the contribution from the kinetics of the retention mechanism to the mass transfer resistance must itself be negligible. This clearly excludes affinity chromatography.

Autologous biologicals--science/regulations.

There has been increased interest in Targeted Biologicals in the United States for several reasons. First, new technology is available to facilitate science-based isolate selection and manufacture. The science of Autologous/Targeted Biologicals will be discussed later in this presentation. A second reason for the increased interest in Targeted Biologicals is the fact that the livestock production methods have changed to favour herd/flock specific products controlled by a veterinarian. There have been changes in management methods such as segregated early weaning in swine, accelerated feeding and early weaning of dairy calves, and forced moulting in poultry. Herds and flocks have increased in stocking density and size. These factors stress animals and may facilitate mutation, strain variation and increased virulence of pathogens. Under these conditions, Traditional Biologicals may not be relevant to current field isolates. Many veterinarians favour vaccinating only for pathogens isolated from a herd/flock. A third reason for the increased interest in these products is that the licensing procedure for Targeted Biologicals is responsive to the needs of livestock producers. The process is abbreviated, requiring much less time and money. This allows for a more rapid response to emerging pathogens, strain variations and mutations, while facilitating the development of monovalent and multivalent products for limited markets or those for minor species.