Postoperative pulmonary complications in older patients undergoing elective surgery with a supraglottic airway device or tracheal intubation

The two most commonly used airway management techniques during general anaesthesia are supraglottic airway devices and tracheal tubes. In older patients undergoing elective non-cardiothoracic surgery under general anaesthesia with positive pressure ventilation, we hypothesised that a composite measure of in-hospital postoperative pulmonary complications would be less frequent when a supraglottic airway device was used compared with a tracheal tube. We studied patients aged ≥ 70 years in 17 clinical centres. Patients were allocated randomly to airway management with a supraglottic airway device or a tracheal tube. Between August 2016 and April 2020, 2900 patients were studied, of whom 2751 were included in the primary analysis (1387 with supraglottic airway device and 1364 with a tracheal tube). Pre-operatively, 2431 (88.4%) patients were estimated to have a postoperative pulmonary complication risk index of 1-2. Postoperative pulmonary complications, mostly coughing, occurred in 270 of 1387 patients (19.5%) allocated to a supraglottic airway device and 342 of 1364 patients (25.1%) assigned to a tracheal tube (absolute difference -5.6% (95%CI -8.7 to -2.5), risk ratio 0.78 (95%CI 0.67-0.89); p < 0.001). Among otherwise healthy older patients undergoing elective surgery under general anaesthesia with intra-operative positive pressure ventilation of their lungs, there were fewer postoperative pulmonary complications when the airway was managed with a supraglottic airway device compared with a tracheal tube.

[Effects of remimazolam versus propofol on postoperative recovery quality in elderly patients undergoing thoracoscopic laparoscopic radical esophagectomy]

Objective: To investigate the effects of remimazolam versus propofol on postoperative recovery quality in elderly patients undergoing thoracoscopic laparoscopic radical esophagectomy. Methods: A total of 108 elderly patients undergoing thoracoscopic laparoscopic radical esophagectomy under general anesthesia in the Affiliated Cancer Hospital of Zhengzhou University from May to October 2022 were prospectively included. The participants were divided into two groups by the random number table method: remimazolam group (R group, n=54) and propofol group (P group, n=54). There were 54 cases in the R group, with 35males and 19 females, and aged (65.4±3.1) years. Meanwhile, there were 54 cases in the P group, with 33males and 21 females, and aged (64.5±3.0) years. Anesthesia was induced as follows: remimazolam 0.2-0.3 mg/kg and remifentanil 0.5-1.0 μg/kg were intravenously injected in R group, while propofol 1-2 mg/kg and remifentanil 0.5-1.0 μg/kg were intravenously injected in P group. Subsequently, anesthesia was maintained as follows: remimazolam 0.4-1.0 mg·kg^-1·h^-1 and remifentanil 0.05-0.2 μg·kg^-1·min^-1 were intravenously infused in group R, while propofol 4-10 mg·kg^-1·h^-1 and remifentanil 0.05-0.2 μg·kg^-1·min^-1 were intravenously infused in group P. Bispectral index (BIS) was maintained at 45-60 during operation. The main outcome measures were the 15-item quality of recovery (QoR-15) scores 1 day before surgery, 1 day and 3 days after surgery. Secondary outcome measures included mean arterial pressure (MAP), heart rate and pulse oxygen saturation (SpO₂) recorded 5 min before anesthesia induction (T₀), 1 min after induction (T₁), 1 min after endotracheal intubation (T₂), immediately after skin incision (T₃) and tracheal extubation (T₄). The incidence of bradycardia and hypotension and the frequency of application of vasoactive drugs during anesthesia were recorded. Restlessness score (RS) and Ramsay sedation scale during the awakening period were recorded. Emergence time, tracheal extubation time, duration of postanesthesia care unit (PACU) stay and postoperative length of hospital stay were recorded. The incidence of postoperative pulmonary infection and other complications were also recorded. Results: The QoR-15 scale scores [M (Q₁, Q₃)] of R group 1 day and 3 days after surgery were 114.0 (109.0, 118.3) and 131.0 (127.8, 133.0), which were higher than those of P group [106.0 (101.0, 112.0) and 127.0 (125.0, 129.3)] (both P<0.001). The incidence of bradycardia, hypotension and the frequency of application of vasoactive drugs of R group during anesthesia were 5.6% (3/54), 35.2% (19/54) and 27.8% (15/54), which were lower than those in P group [33.3% (18/54), 63.0% (34/54) and 55.6% (30/54), respectively] (all P<0.05). RS score during the awakening period in R group was 0.9±0.5, which was lower than that of P group (1.1±0.6) (P=0.046). Emergence time, tracheal extubation time and postoperative length of hospital stay of R group were (15.4±4.9) min, (16.6±4.7) min and (11.6±1.4) d, which were shorter than those of P group [(26.2±6.4) min, (27.8±5.8) min and (12.6±1.3) d] (all P<0.05). There were no statistically significant differences in Ramsay scores during the awakening period, duration of PACU stay and the incidence of postoperative complications (all P>0.05). Conclusions: Both remimazolam and propofol can achieve satisfactory postoperative recovery quality in elderly patients undergoing thoracoscopic laparoscopic radical esophagectomy. Remimazolam has more stable hemodynamics and lower incidence of adverse reactions.

[Effects of desflurane and sevoflurane anesthesia on postoperative recovery after long-term tumor surgery]

Objective: To analyze the effects of desflurane and sevoflurane anesthesia on postoperative recovery after long lasting tumor surgery. Methods: One hundred and sixty patients undergoing endoscopic radical esophagectomy and gastrectomy (80 cases of each surgical type) from November 2019 to March 2020 at Henan Cancer Hospital, were randomized into 4 groups(n=40): group CS (esophageal cancer+sevoflurane anesthesia), group DS (esophageal cancer+desflurane anesthesia),group CW (stomach cancer+sevoflurane anesthesia) and group DW (gastric cancer+desflurane anesthesia). General anesthesia was induced by intravenous agents in all four groups, which were maintained by inhaled anesthetic during the operation. The mean arterial pressure (MAP), heart rate (HR), and surplus pulse O(2) (SpO(2)) immediately before induction (T(1)), the moment of operation begin (T(2)), operation end (T(3)) and extubation (T(4)) were recorded. Also, the duration required for inhalation anesthetic alveolar concentration reaching 0.5 minimum alveolar concentration (MAC) during induction, the alveolar anesthetic concentration at the beginning of the operation, the duration required for XMAC (patients specific alveolar concentration) declining to 0.5 MAC on recovery period, and the duration of alveolar concentration of 0.5 MAC declining to 0.2 MAC were determined. Additionally, the durations of spontaneous breathing recovery, eyes opening, extubation and recovery of consciousness were recorded. Finally, restlessness score (RS) during recovery period was used to evaluate postoperative agitation. Results: Compared with group CS and group CW, no significant differences in MAP, HR, SpO(2) in group DS and group DW at T(1) to T(4) were found (all P>0.05). The durations required for inhalation anesthetic alveolar concentration reaching 0.5 MAC were (5.6±1.3), (5.8±2.1), (3.5±1.5) and (3.8±1.0) min in group CS, group CW, group DS and group DW, where the durations in group DS and group DW were significantly shorter than those in group CS and group CW (F=32.538, P<0.05). The durations of alveolar concentration of 0.5 MAC declining to 0.2 MAC were (6.4±2.2), (7.0±1.5), (4.2±2.2) and (4.1±1.5) min in group CS, group CW, group DS and group DW, and the durations in group DS and group DW were significantly shortened as compared with group CS and group CW (F=42.113, P<0.05). Compared with group CS and group CW, group DS and group DW required significantly shorter time for spontaneous breathing recovery, eye opening,extubation, and directional force recovery after operation (all P<0.05). Conclusions: Both desflurane and sevoflurane anesthesia can achieve satisfactory anesthesia depth during long lasting tumor surgery. Desflurane can shorten the recovery time and early extubation, and improve the quality of recovery.

Randomized clinical trial of continuous transversus abdominis plane block, epidural or patient-controlled analgesia for patients undergoing laparoscopic colorectal cancer surgery

Background

The optimal analgesia regimen after laparoscopic colorectal cancer surgery is unclear. The aim of the study was to characterize the beneficial effects of continuous transversus abdominis plane (TAP) blocks initiated before operation on outcomes following laparoscopic colorectal cancer surgery.

Methods

Patients undergoing surgery for colorectal cancer were divided randomly into three groups: combined general–TAP anaesthesia (TAP group), combined general–thoracic epidural anaesthesia (TEA group) and standard general anaesthesia (GA group). The primary endpoint was duration of hospital stay. Secondary endpoints included gastrointestinal motility, pain scores and plasma levels of cytokines.

Results

In total, 180 patients were randomized and 165 completed the trial. The intention-to-treat analysis showed that duration of hospital stay was significantly longer in the TEA group than in the TAP and GA groups (median 4·1 (95 per cent c.i. 3·8 to 4·3) versus 3·1 (3·0 to 3·3) and versus 3·3 (3·2 to 3·6) days respectively; both P &lt; 0·001). Time to first flatus was earlier in the TAP group (P &lt; 0·001). Visual analogue scale (VAS) scores during coughing were lower in the TAP and TEA groups than the GA group (P &lt; 0·001). Raised plasma levels of vascular endothelial growth factor C, interleukin 6, adrenaline and cortisol were attenuated significantly by continuous TAP block.

Conclusion

Continuous TAP analgesia not only improved gastrointestinal motility but also shortened duration of hospital stay. A decreased opioid requirement and attenuating surgical stress response may be potential mechanisms. Registration number: ChiCTR-TRC-1800015535 (http://www.chictr.org.cn).

Effects of anaesthesia on proliferation, invasion and apoptosis of LoVo colon cancer cells in vitro

Tumour cell proliferation, invasion and apoptosis are crucial steps in tumour metastasis. We evaluated the effect of serum from patients undergoing colon cancer surgery receiving thoracic epidural and propofol anaesthesia on colon cancer cell biology. Patients were randomly assigned to receive propofol anaesthesia with a concomitant thoracic epidural (PEA, n = 20) or sevoflurane anaesthesia with opioid analgesia (SGA, n = 20). Venous blood was obtained before induction of anaesthesia and 24 hours postoperatively. The LoVo colon cancer cells were cultured with patient serum from both groups and the effects on proliferation, invasion and apoptosis were measured. Twenty-four hours after surgery, the absorbance value of LoVo cells at 10% serum concentration from PEA was decreased when compared with SGA (0.302 (0.026) vs 0.391 (0.066), p = 0.005). The inhibitory rate of LoVo cells at 10% serum concentration from PEA was higher than that from SGA (p = 0.004) 24 h after surgery. The number of invasive LoVo cells at 10% serum concentration from PEA was reduced when compared with SGA (44 (4) vs 62 (4), p < 0.001). Exposure of LoVo cells to postoperative serum from patients receiving PEA led to a higher luminescence ratio (apoptosis) than those receiving SGA (0.36 (0.04) vs 0.27 (0.05), p < 0.001). Serum from patients receiving PEA for colon cancer surgery inhibited proliferation and invasion of LoVo cells and induced apoptosis in vitro more than that from patients receiving SGA. Anaesthetic technique might influence the serum milieu in a way that affects cancer cell biology and, thereby, tumour metastastasis.

Systemic or intra-amygdala infusion of an endocannabinoid CB1 receptor antagonist AM251 blocked propofol-induced anterograde amnesia

Propofol is well-known for its anterograde amnesic actions. However, a recent experiment showed that propofol can also produce retrograde memory enhancement effects via an interaction with the endocannabinoid CB1 system. Therefore, the authors hypothesized that the regulating effect of propofol on the endocannabinoid CB1 system might also decrease the anterograde amnesic effect of propofol under some conditions, which might be a risk factor for intraoperative awareness. Since, the basolateral amygdala (BLA) has been confirmed to mediate propofol-induced anterograde amnesia and the BLA contains a high concentration of CB1 receptors, the authors investigated whether and how the endocannabinoid system, particularly the CB1 receptor within BLA, influences propofol-induced anterograde amnesia. Male Sprague-Dawley rats trained with inhibitory avoidance (IA) were systematically pre-trained using a memory-impairing dose of propofol (25 mg/kg). Before propofol administration, rats received an intraperitoneal injection of a CB1 receptor antagonist AM251 (1 mg/kg or 2 mg/kg) or a bilateral intra-BLA injection of AM251 (0.6 ng or 6 ng per 0.5 μl). Twenty-four hours after IA training, the IA retention latency was tested. It was found that systemic or intra-BLA injection of a non-regulating dose of AM251 (2 mg/kg or 6 ng per 0.5 μl, respectively) blocked the memory-impairing effect of propofol. These results indicate that the anterograde amnesic effect of propofol is mediated, in part, by activation of the CB1 cannabinoid receptors in the BLA.

Generation of a novel factor IX with augmented clotting activities in vitro and in vivo

BACKGROUND

Hemophilia B is an X-linked inherited disorder caused by the lack of functional factor IX (FIX). Currently, treatment of hemophilia B is performed by intravenous infusion of plasma-derived or recombinant FIX.

OBJECTIVE

In an effort to reduce factor usage and cost, we investigated the potential use of FIX variants with enhanced specific clotting activity.

METHODS

Seven recombinant FIX variants using alanine replacement were generated and assayed for their activity in vitro and in vivo.

RESULTS

One variant containing three substitutions (V86A/E277A/R338A, FIX-Triple) exhibited 13-fold higher specific clotting activity and a 10-fold increased affinity for human FVIIIa compared with FIX-wild-type (FIX-WT) and was thus investigated systematically in vivo. Liver-specific FIX-Triple gene expression following hydrodynamic plasmid delivery revealed a 3.5-fold higher specific clotting activity compared with FIX-WT. Human FIX-Triple and FIX-WT knock-in mice were generated and it was confirmed that FIX-Triple has 7-fold higher specific clotting activity than FIX-WT under normal physiological conditions. Protein infusion of FIX-Triple into hemophilia B mice resulted in greater improvement of hemostasis than that achieved with FIX-WT. Moreover, tail-vein administration of a serotype 8 recombinant Adeno-associated vector (AAV8) expressing either FIX-WT or FIX-Triple in hemophilia B mice demonstrated a 7-fold higher specific clotting activity of FIX-Triple than FIX-WT.

CONCLUSIONS

Our results indicate that the FIX-Triple variant exhibits significantly enhanced clotting activity relative to FIX-WT due to tighter binding to FVIIIa, as demonstrated both in vitro and in vivo. Therefore, FIX-Triple is a good candidate for further evaluation in protein replacement therapy as well as gene-based therapeutic strategies.

Ultrasound with microbubbles enhances gene expression of plasmid DNA in the liver via intraportal delivery

Current ultrasound (US)-mediated gene delivery methods are inefficient due, in part, to a lack of US optimization. We systematically explored the use of microbubbles (MBs), US parameters and plasmid delivery routes to improve gene transfer into the mouse liver. Co-presentation of plasmid DNA (pDNA), 10% Optison MBs and pulsed 1-MHz US at a peak negative pressure of 4.3 MPa significantly increased luciferase gene expression with pDNA delivered by intrahepatic injection to the left liver lobe. Intraportal injection delivered pDNA and MBs to the whole liver; with insonation, all lobes expressed the transgene, thus increasing total gene expression. Gene expression was also dependent on acoustic pressure over the range of 0-4.3 MPa, with a peak effect at 3 MPa. An average of 85-fold enhancement in gene delivery was achieved. No enhancement was observed below 0.25 MPa. Increasing pulse length while decreasing pulse repetition frequency and exposure time to maintain a constant total energy during exposure did not further improve transfection efficiency, nor did extend the US exposure pre- or postinjection of pDNA. The results indicate that coupled with MBs, US can more efficiently and dose-dependently enhance gene expression from pDNA delivered via portal vein injection by an acoustic mechanism of inertial cavitation.

Expression of foreign genes in chicks by hydrodynamics-based naked plasmid transfer in vivo

The study of gene function in vivo is considered one of the top achievements of modern biology, inasmuch as it provides tools to study gene function in the context of the whole animal. In chickens, techniques of DNA-mediated gene transfer are less advanced than in other animal or livestock models, and remain a significant challenge. The study presented here is the first to show that a hydrodynamics-based gene-transfer technique, originally developed for naked DNA transfer in mice, can be applied to chickens. Rapid injection of naked plasmids containing expression cassettes into the jugular vein of 6- to 10-day-old chicks resulted in specific expression of the transgenes. A CMV promoter-driven luciferase reporter gene was expressed at significant levels in the liver during the first 3 days post-injection with lower levels also detected in the kidney. Significantly, all injected birds showed detectable levels of luciferase expression. Similarly, injection of a plasmid containing the secreted human coagulation factor IX (hFIX) gene under the control of human alpha-1-anti-trypsin promoter resulted in detectable levels of the hFIX in the plasma during the first 2 days post-injection. The method described herein has the potential for a quick and simple route for gain and loss-of function experiments in chicken liver and kidney, as well as for studying systemic effects of secreted proteins and hormones.

Complete and sustained phenotypic correction of hemophilia B in mice following hepatic gene transfer of a high-expressing human factor IX plasmid

Therapeutic correction of hemophilia B was achieved by rapid infusion of a large-volume solution containing a high-expressing human factor IX (hFIX) plasmid into the tail vein of hemophilia B mice. hFIX circulated at therapeutic levels (1-5 micro g mL-1) in all animals for more than 1 year as determined by both species-specific antigen assay and an activated partial thromboplastin time (APTT)-based clotting assay. There was acute, transient hepatic tissue damage by the infusion procedure and no significant inhibitory anti-hFIX antibodies developed. No bleeding episode was observed during or after treatment. Immunohistochemical studies indicated that the hFIX gene was exclusively expressed in hepatocytes, and that transduced cells had readily detectable hFIX protein at 4 h postinfusion, and stainable protein persisted for up to 1 year. Repeated infusions of hFIX plasmids boosted the hFIX expression to higher levels. These results demonstrate that hemophilia B can be treated by gene transfer of naked hFIX plasmids.

Long-term and therapeutic-level hepatic gene expression of human factor IX after naked plasmid transfer in vivo

Naked DNA transfer of a high-expressing human factor IX (hFIX) plasmid yielded long-term (over 1 1/2 years) and therapeutic-level (0.5-2 microg/ml) gene expression of hFIX from mouse livers. The expression cassette contained a hepatic locus control region from the ApoE gene locus, an alpha1-anti-trypsin promoter, hFIX cDNA, a portion of the hFIX first intron, and a bovine growth hormone polyadenylation signal. In contrast, a hFIX plasmid containing the expression cassette without effective regulatory elements produced initially low-level gene expression that rapidly declined to undetectable levels. Southern analyses of the cellular DNA indicated that the majority of the input genome from either vector persisted as episomal forms of the original plasmids. Together with RT-PCR analyses of the transcripts, these data indicated that at least two processes are critical for sustained gene expression: persistence of vector DNA and transcriptional/posttranscriptional activation. Liver regeneration after partial hepatectomy resulted in a significant decline in transgene expression, further suggestive of decreased episomal plasmid maintenance rather than transgene integration. Transaminase levels and liver histology showed that rapid intravenous plasmid injection into mice induced transient focal acute liver damage (< 5% of hepatocytes), which was rapidly repaired within 3 to 10 days and resulted thereafter in histologically normal tissue. No significant differences were observed between rapid injection of plasmid and saline control solutions. Transient, very low level antibodies directed against hFIX did not prevent the circulation of therapeutic levels of the protein. Gene transfer of hFIX plasmid DNA into liver elicited neither transgene-specific cytotoxic effect nor long-term toxicity. These results demonstrate that long-term expression of hFIX can be achieved by nonviral plasmid transfer and suggest that this occurs independent of integration.

Inclusion of the hepatic locus control region, an intron, and untranslated region increases and stabilizes hepatic factor IX gene expression in vivo but not in vitro

We systematically compared human factor IX gene expression from a variety of plasmids containing different cis-regulatory sequences after transfection into different hepatocyte cell lines, or in vivo, after their injection into the livers of mice. Although there was a 1.5- to 2.0-fold variation in gene expression from cultured cells, a 65-fold variation was observed in the in vivo studies. We found that a plasmid containing the apolipoprotein E locus control region (HCR), human alpha1-antitrypsin (hAAT) promoter, hFIX minigene (hFIXmg) sequence including a portion of the first intron (intron A), 3'-untranslated region (3'-UTR), and a bovine growth hormone polyadenylation signal (bpA) produced the highest serum level of human factor IX, reaching 18 microg/ml (normal = 5 microg/ml) 1 day after injection. Although most of the plasmid DNAs resulted in transient gene expression, inclusion of an intron, a polyadenylation signal from either the 1.7-kb 3'-UTR or the 0.3-kb bpA, and the HCR resulted in persistent and therapeutic levels of hFIX gene expression, ranging from 0.5 to 2 microg/ml (10 to 40% of normal) for 225 days (length of experiment). These data underscore the importance of cis sequences for enhancing in vivo hepatic gene expression and reemphasize the lack of correlation of gene expression in tissue culture and in vivo studies.

Nonrandom transduction of recombinant adeno-associated virus vectors in mouse hepatocytes in vivo: cell cycling does not influence hepatocyte transduction

Recombinant adeno-associated virus vectors (rAAV) show promise in preclinical trials for the treatment of genetic diseases including hemophilia. Liver-directed gene transfer results in a slow rise in transgene expression, reaching steady-state levels over a period of 5 weeks concomitant with the conversion of the single-stranded rAAV molecules into high-molecular-weight concatemers in about 5% of hepatocytes. Immunohistochemistry and RNA in situ hybridization show that the transgene product is made in about approximately 5% of hepatocytes, suggesting that most rAAV-mediated gene expression occurs in hepatocytes containing the double-stranded concatemers. In this study, the mechanism(s) involved in stable transduction in vivo was evaluated. While only approximately 5% of hepatocytes are stably transduced, in situ hybridization experiments demonstrated that the vast majority of the hepatocytes take up AAV-DNA genomes after portal vein infusion of the vector. Two different vectors were infused together or staggered by 1, 3, or 5 weeks, and two-color fluorescent in situ hybridization and molecular analyses were performed 5 weeks after the infusion of the second vector. These experiments revealed that a small but changing subpopulation of hepatocytes were permissive to stable transduction. Furthermore, in animals that received a single infusion of two vectors, about one-third of the transduced cells contained heteroconcatemers, suggesting that dimer formation was a critical event in the process of concatemer formation. To determine if the progression through the cell cycle was important for rAAV transduction, animals were continuously infused with 5'-bromo-2'-deoxyuridine (BrdU), starting at the time of administration of a rAAV vector that expressed cytoplasmic beta-galactosidase. Colabeling for beta-galactosidase and BrdU revealed that there was no preference for transduction of cycling cells. This was further confirmed by demonstrating no increase in rAAV transduction efficiencies in animals whose livers were induced to cycle at the time of or after vector administration. Taken together, our studies suggest that while virtually all hepatocytes take up vector, unknown cellular factors are required for stable transduction, and that dimer formation is a critical event in the transduction pathway. These studies have important implications for understanding the mechanism of integration and may be useful for improving liver gene transfer in vivo.

Effect of long-term selection for early postnatal growth rate on survival and prenatal development of transferred mouse embryos

Reciprocal embryo transfer procedures were performed among mouse selection lines to examine prenatal maternal effects on survival and development of transferred embryos. Mice were from generations 28 and 29 of an experiment to select for (i) increased body weight again from 0 to 10 days (E+); (ii) decreased body weight gain from 0 to 10 days (E-); or (iii) a randomly bred control line (C). A total of 118 embryo transfer procedures performed 12 h after conception resulted in 983 progeny born to 89 litters. There was a 39% overall embryo survival rate and 75% overall pregnancy success rate. Response to superovulation and oestrous synchronization was significantly lower (P < 0.01) in the E+ line. E+ individuals that did superovulate produced an average of 37 oocytes per flush, which was significantly higher than in the control line mice (29 oocytes per flush; P < 0.01). The ability to complete pregnancy successfully was not influenced by uterine environment or embryo-uterine interaction. In contrast, embryo survival in successful pregnancies was significantly affected by uterine environment. There were large maternal effects for body weight and tail length at birth; E+ recipients produced pups that were significantly larger than E- recipient pups (P < 0.01), which in turn were significantly larger than pups gestated by control recipients (P < 0.01).

Effect of long-term selection for early postnatal growth rate on survival and prenatal development of transferred mouse embryos

Reciprocal embryo transfer procedures were performed among mouse selection lines to examine prenatal maternal effects on survival and development of transferred embryos. Mice were from generations 28 and 29 of an experiment to select for (i) increased body weight again from 0 to 10 days (E+); (ii) decreased body weight gain from 0 to 10 days (E-); or (iii) a randomly bred control line (C). A total of 118 embryo transfer procedures performed 12 h after conception resulted in 983 progeny born to 89 litters. There was a 39% overall embryo survival rate and 75% overall pregnancy success rate. Response to superovulation and oestrous synchronization was significantly lower (P < 0.01) in the E+ line. E+ individuals that did superovulate produced an average of 37 oocytes per flush, which was significantly higher than in the control line mice (29 oocytes per flush; P < 0.01). The ability to complete pregnancy successfully was not influenced by uterine environment or embryo-uterine interaction. In contrast, embryo survival in successful pregnancies was significantly affected by uterine environment. There were large maternal effects for body weight and tail length at birth; E+ recipients produced pups that were significantly larger than E- recipient pups (P < 0.01), which in turn were significantly larger than pups gestated by control recipients (P < 0.01).

Uterine and postnatal maternal effects in mice selected for differential rate of early development

A series of mouse lines was produced by long-term restricted index selection for divergent rate of growth during early and late postnatal development. The selection program was based on the following treatments: E(+) and E(-) lines were selected to alter birth to 10-day weight gain while holding late gain for both lines constant and a control line was established via random selection. Using embryo transfer and crossfostering methodology, we partitioned postnatal growth for E(+), E(-), and C lines into progeny genetic, uterine maternal, and nurse maternal components. Selection for differential early growth resulted in correlated response in uterine and nurse maternal effects on body weights, with significant genetic-by-environment interactions. Significant uterine effects were also observed in tail length measurements. Direct uterine effects on body weight were relatively small and resulted in growth rate differences early in development. Nurse effects were large, resulting in modification of progeny growth trajectory especially during early postnatal development. Genetic-by-uterine interactions were large and demonstrate progeny-specific effects of the prenatal uterine environment.

Persistent and therapeutic concentrations of human factor IX in mice after hepatic gene transfer of recombinant AAV vectors

Haemophilia B, or factor IX deficiency, is a X-linked recessive disorder that occurs in about one in 25,000 males, and severely affected people are at risk for spontaneous bleeding into numerous organs. Bleeding can be life-threatening or lead to chronic disabilities with haemophilic arthropathy. The severity of the bleeding tendency varies among patients and is related to the concentration of functional plasma factor IX. Patients with 5-30% of the normal factor IX have mild haemophilia that may not be recognized until adulthood or after heavy trauma or surgery. Therapy for acute bleeding consists of the transfusion of clotting-factor concentrates prepared from human blood and recombinant clotting factors that are currently in clinical trials. Both recombinant retroviral and adenoviral vectors have successfully transferred factor IX cDNA into the livers of dogs with haemophilia B. Recombinant retroviral-mediated gene transfer results in persistent yet subtherapeutic concentrations of factor IX and requires the stimulation of hepatocyte replication before vector administration. Recombinant adenoviral vectors can temporarily cure the coagulation defect in the canine haemophilia B model; however, an immune response directed against viral gene products made by the vector results in toxicity and limited gene expression. The use of recombinant adeno-associated virus (rAAV) vectors is promising because the vector contains no viral genes and can transduce non-dividing cells. The efficacy of in vivo transduction of non-dividing cells has been demonstrated in a wide variety of tissues. In this report, we describe the successful transduction of the liver in vivo using r-AAV vectors delivered as a single administration to mice and demonstrate that persistent, curative concentrations of functional human factor IX can be achieved using wild-type-free and adenovirus-free rAAV vectors. This demonstrates the potential of treating haemophilia B by gene therapy at the natural site of factor IX production.

Transcriptional regulation of the gene coding for human protein C

The promoter for the gene coding for human protein C has been characterized as to nucleotide sequences that regulate the synthesis of mRNA. The major transcription start site was found 65 nucleotides upstream from the first intron/exon boundary along with two minor sites. Functional characterization of 1528 base pairs at the 5'-end of the gene was then carried out by chloramphenicol acetyltransferase reporter assays, protection from DNase I digestion, and electrophoretic mobility shift assays employing HepG2 and HeLa cells. One of the upstream regions (nucleotides -25 to +9) contained binding sites for at least two different transcription factors, including a hepatic nuclear factor 1-binding site (-10 to +9) and two overlapping and oppositely oriented hepatic nuclear factor 3-binding sites (-25 to -11). A second major region (PCE1) (+12 to +30) appeared to be a unique, liver-specific regulatory sequence. An Sp1-binding site in exon I (+58 to +65) was also recognized by cotransfection experiments with an Sp1 expression plasmid. Specific mutations in these promoter elements reduced transcriptional activity and abolished the binding of hepatic nuclear proteins. Finally, a strong silencer element (PCS1) (between -162 and -82) and two possible liver-specific enhancer regions (PCE2 and PCE3), which interact coordinately with the promoter elements, were also found (between -1462 and -162).

Liver-specific expression of the human factor VII gene

Promoter and silencer elements of the immediate 5' flanking region of the gene coding for human factor VII were identified and characterized. The major transcription start site, designated as +1, was determined by RACE (rapid amplification of cDNA ends) analysis of human liver cDNA and was found to be located 50 bp upstream from the translation start site. Two minor transcription start sites were found at bp +32 bp and +37. Progressive deletions of the 5' flanking region were fused to the chloramphenicol acetyltransferase reporter gene and transient expression in HepG2 and HeLa cells was measured. Two promoter elements that were essential for hepatocyte-specific transcription were identified. The first site, FVIIP1, located at bp -19 to +1, functioned independently of orientation or position and contributed about one-third of the promoter activity of the factor VII gene. Electrophoretic mobility-shift, competition, and anti-hepatocyte nuclear factor 4 (HNF4) antibody supershift experiments demonstrated that this site contained an HNF-4 binding element homologous to the promoters in the genes coding for factor IX and factor X. The second site, FVIIP2, located at bp -50 to -26, also functioned independent of orientation or position and contributed about two thirds of the promoter activity in the gene for factor VII. Functional assays with mutant sequences demonstrated that a 10-bp G + C-rich core sequence which shares 90% sequence identity with the prothrombin gene enhancer was essential for the function of the second site. Mobility-shift and competition assays suggested that this site also binds hepatic-specific factors as well as the transcription factor Sp1. Two silencer elements located upstream of the promoter region spanning bp -130 to -103 (FVIIS1 site) and bp -202 to -130 (FVIIS2) were also identified by reporter gene assays.

Liver-specific expression of the gene coding for human factor X, a blood coagulation factor

Factor X is a vitamin K-dependent glycoprotein that plays an essential role in both the intrinsic and extrinsic pathways of blood coagulation. Studies on a recombinant lambda phage containing the 5'-flanking region of the human factor X gene showed that the factor X gene was linked to and was located at the 3' end of the factor VII gene: the initiation codon of the factor X gene was 2823 base pairs (bp) downstream from the polyadenylation site of the factor VII gene. This 2.8-kilobase intergenic region, and progressively deleted fragments of it, was fused to the chloramphenicol acetyltransferase gene, and transient expressions in HepG2 cells, human fibroblasts, and Chinese hamster ovary cells were measured. A liver-specific promoter element, FXP1-binding site, essential for hepatocyte-specific transcription was identified. This promoter sequence, further localized to -63 to -42 bp in DNase I footprint studies, was homologous to LF-A1 or hepatic nuclear factor-4 recognition sequence and was equally functional in the normal and inverse orientations. FXP1 site bound to nuclear protein(s) from HepG2 cells and complex formation was partially abolished by the presence of duplex oligonucleotides containing liver factor-A1 or hepatic nuclear factor-4-binding sequences. Two additional positive elements located upstream of the promoter region, spanning from -215 to -149 bp (FXP2 site), and -457 to -351 bp (FXP3 site), were also established by reporter gene assays.

Chromosomal mapping of the human annexin IV (ANX4) gene

Annexin IV (placental anticoagulant protein II) is a member of the annexin or lipocortin family of calcium-dependent phospholipid-binding proteins. A cDNA for human annexin IV was isolated from a placental library that is 675 bases longer in the 3' untranslated region than previously reported, indicating the existence of alternative mRNA processing for this gene. Genomic Southern blotting with a cDNA probe indicated a gene size of 18-56 kb. Primers developed for polymerase chain reaction (PCR) allowed amplification of a 1.6-kb portion of the ANX4 gene. DNA sequence analysis showed that this PCR product contained a single intron with exon-intron boundaries in exactly the same position as in the mouse annexin I and annexin II genes. PCR analysis of a somatic cell hybrid panel mapped the ANX4 gene to chromosome 2, and in situ hybridization with a cDNA probe showed a unique locus for ANX4 at 2p13. This study provides further evidence that genes for the annexins are dispersed throughout the genome but are similar in size and exon-intron organization.

Chromosomal localization of the human annexin III (ANX3) gene

The annexins or lipocortins are a new family of calcium-dependent phospholipid-binding proteins. Annexin III has been previously identified as inositol 1,2-cyclic phosphate 2-phosphohydrolase (EC 3.1.4.36), an enzyme of inositol phosphate metabolism, and also as placental anticoagulant protein III, lipocortin III, calcimedin 35-alpha, and an abundant neutrophil cytoplasmic protein. In this study, the gene (ANX3) encoding annexin III was localized to human chromosome 4 at band q21 (q13-q22) by (1) polymerase chain reaction analysis of a human-rodent hybrid cell panel, confirmed by genomic Southern blot analysis of the same panel with a cDNA probe and (2) in situ hybridization with a cDNA probe.

Placental anticoagulant proteins: isolation and comparative characterization four members of the lipocortin family

Previously we isolated and characterized a placental anticoagulant protein (PAP or PAP-I), which is a Ca2+-dependent phospholipid binding protein [Funakoshi et al. (1987) Biochemistry 26, 5572] and a member of the lipocortin family [Funakoshi et al. (1987) Biochemistry 26, 8087]. In this study, three additional anticoagulant proteins (PAP-II, PAP-III, and PAP-IV) were simultaneously isolated from human placental homogenates prepared in the presence of 5 mM ethylenediaminetetraacetic acid. The isoelectric points of PAP-I, PAP-II, PAP-III, and PAP-IV were 4.8, 6.1, 5.9, and 8.1, respectively, and their apparent molecular weights were 32,000, 33,000, 34,000, and 34,500, respectively. Amino acid sequences of cyanogen bromide fragments of these proteins showed that PAP-III was a previously unrecognized member of the lipocortin family, while PAP-II was probably the human homologue of porcine protein II and PAP-IV was a derivative of lipocortin II truncated near the amino terminus. Comparative studies showed that all four proteins inhibited blood clotting and phospholipase A2 activity with potencies consistent with their measured relative affinities for anionic phospholipid vesicles. However, PAP-IV bound to phospholipid vesicles approximately 160-fold more weakly than PAP-I, while PAP-II and PAP-III bound only 2-fold and 3-fold more weakly. These results increase to six the number of lipocortin-like proteins known to exist in human placenta. The observed differences in phospholipid binding may indicate functional differences among the members of the lipocortin family despite their considerable structural similarities.

Molecular basis of ionic strength effects: interaction of enzyme and sulfate ion in CO2 hydration and HCO3- dehydration reactions catalyzed by carbonic anhydrase II

CO2 hydration and HCO3- dehydration reactions catalyzed by carbonic anhydrase II have been examined at various concentrations of sodium sulfate with a stopped-flow technique. We find that at low ionic strength CO2 hydration and HCO3- dehydration reaction rates remain unaffected by varying the salt concentration at pH higher than 7.0, while the reaction rates decrease with increasing ionic strength at low pH. For CO2 hydration reactions, salt effects reside only in the kcat term, not in the Km term, whereas for HCO3- dehydration reactions, salt effects reside only in the Km term, not in the kcat term. In this regime, the salt concentration dependence of the turnover rate for CO2 hydration at low pH is attributed to an electrostatic effect on the ionization constants of the enzyme and/or enzyme-substrate complex, which in turn affect the pH profile of kcat. The rates of the bimolecular interaction between the uncharged CO2 molecule and carbonic anhydrase II at high pH are unaffected by low salt concentration while the rates of the bimolecular interaction of HCO3- with enzyme at low pH decrease with increasing salt concentration, consistent with a negative salt effect on an electrostatically enhanced diffusion of the negatively charged substrate to the positively charged active site. These bimolecular reactions between enzyme and substrate at low ionic strength obey rate equations derived from the Debye-Hückel limiting law and the transition-state theory. Simple linear relationships between the logarithm of the catalytic constant, log kdenz, and the square root of the ionic strength were established.(ABSTRACT TRUNCATED AT 250 WORDS)