A Cdc28 mutant uncouples G1 cyclin phosphorylation and ubiquitination from G1 cyclin proteolysis

Proteolysis of the yeast G(1) cyclins is triggered by their Cdc28-dependent phosphorylation. Phosphorylated Cln1 and Cln2 are ubiquitinated by the SCF-Grr1 complex and then degraded by the 26 S proteasome. In this study, we identified a cak1 allele in a genetic screen for mutants that stabilize the yeast G(1) cyclins. Further characterization showed that Cln2HA was hypophosphorylated, unable to bind Cdc28, and stabilized in cak1 mutants at the restrictive temperature. Hypophosphorylation of Cln2HA could thus explain its stabilization. To test this possibility, we expressed a Cak1-independent mutant of Cdc28 (Cdc28-43244) in cak1 mutants and found that Cln2HA phosphorylation was restored, but surprisingly, the phospho-Cln2HA was stabilized. When bound to Cdc28-43244, Cln2HA was recognized and polyubiquitinated by SCF-Grr1. The Cdc28-43244 mutant thus reveals an unexpected complexity in the degradation of polyubiquitinated Cln2HA by the proteasome.

Remifentanil and fentanyl during anaesthesia for major abdominal and gynaecological surgery. An open, comparative study of safety and efficacy

BACKGROUND

and objective This open, multicentre study compared the efficacy and safety of remifentanil with fentanyl during balanced anaesthesia with 0.8% isoflurane (end-tidal concentration) for major abdominal and gynaecological surgery, and the efficacy and safety of remifentanil for pain management in the immediate postoperative period.

METHODS

Two-hundred and eighty-six patients were randomized to receive remifentanil 1 microg kg(-1) followed by 0.2 microg kg(-1) min-1 (n=98), remifentanil 2 microg kg(-1) followed by 0.4 microg kg(-1) min(-1) (n=91) or fentanyl 3 microg kg(-1) (n=97) at induction. Thereafter, the study opioids and isoflurane were titrated to effect during the operation.

RESULTS

Compared with fentanyl, remifentanil 2 microg kg(-1) followed by 0.4 microg kg(-1) min(-1) reduced the incidence of response to tracheal intubation (30% vs. 13%, P < 0.01), skin incision (33% vs. 4%, P < 0.001) and skin closure (11% vs. 3%, P < 0.05), respectively. Patients receiving remifentanil 1 microg kg(-1) followed by 0.2 microg kg(-1) min(-1) had fewer responses to skin incision than the fentanyl group (12% vs. 33%, P < 0.001), but the incidences of response to tracheal intubation and skin closure were similar. Significantly fewer patients in both remifentanil groups had > or = 1 responses to surgical stress intraoperatively compared with fentanyl (68% and 48% vs. 87%, P < 0.003). The mean isoflurane concentrations required were less in both remifentanil groups compared with the fentanyl group (0.1%, P=0.05). In remifentanil-treated patients, continuation of the infusion at 0.1 microg kg(-1) min(-1) with titration increments of +/- 0.025 microg kg(-1) min(-1) was effective for the management of immediate postoperative pain prior to transfer to morphine analgesia. However, a high proportion of patients experienced at least moderate pain whilst the titration took place.

CONCLUSIONS

Anaesthesia combining isoflurane with a continuous infusion of remifentanil was significantly more effective than fentanyl at blunting responses to surgical stimuli. Significantly fewer patients responded to tracheal intubation with remifentanil at 0.4 microg kg(-1) min(-1), supporting the use of a higher initial infusion rate before intubation. Both remifentanil and fentanyl were well-tolerated, with reported adverse events typical of mu-opioid agonists.

Xbp1-mediated repression of CLB gene expression contributes to the modifications of yeast cell morphology and cell cycle seen during nitrogen-limited growth

Yeast cells undergo morphological transformations in response to diverse environmental signals. One such event, called pseudohyphal differentiation, occurs when diploid yeast cells are partially starved for nitrogen on a solid agar medium. The nitrogen-starved cells elongate, and a small fraction form filaments that penetrate the agar surface. The molecular basis for the changes in cell morphology and cell cycle in response to nitrogen limitation are poorly defined, in part because the heterogeneous growth states of partially starved cells on agar media are not amenable to biochemical analysis. In this work, we used chemostat cultures to study the role of cell cycle regulators with respect to yeast differentiation in response to nitrogen limitation under controlled, homogeneous culture conditions. We found that Clb1, Clb2, and Clb5 cyclin levels are reduced in nitrogen-limited chemostat cultures compared to levels in rich-medium cultures, whereas the Xbp1 transcriptional repressor is highly induced under these conditions. Furthermore, the deletion of XBP1 prevents the drop in Clb2 levels and inhibits cellular elongation in nitrogen-limited chemostat cultures as well as inhibiting pseudohyphal growth on nitrogen-limited agar media. Deletion of the CLB2 gene restores an elongated morphology and filamentation to the xbp1Delta mutant in response to nitrogen limitation. Transcriptional activation of the XBP1 gene and the subsequent repression of CLB gene expression are thus key responses of yeast cells to nitrogen limitation.

[Quality assurance program for postoperative pain management: impact of the Consensus Conference of the French Society of Anesthesiology and Intensive Care]

OBJECTIVE

To assess the impact of a pain management quality assurance program (PQAP) after abdominal surgery. The means used were mainly based on the French Society of anaesthesiology's pain management guidelines.

STUDY DESIGN

Prospective evaluation using a before after study design: two audits among surgical patients: a first one in 1997 before implementation of PQAP, and a second one year later.

PATIENTS AND METHODS

First, standards were defined including objectives about pain relief and patient satisfaction. After analysis of discrepancy observed between these objectives and the data of the first audit, a pain management program was introduced that included education of physicians, nurses and patients, systematic assessment of pain, organized pain relief protocols and implementation of modern analgesic technologies.

RESULTS

201 consecutive inpatients were evaluated in the first audit, and 117 in the second one. Comparing the second audit with baseline, the visual analog pain scores decreased during the five postoperative days, and the rate of very satisfied patients increased (36% versus 26%). 43% of the patients were given a regular analgesic medication in 1998 versus 15% in 1997. 65% of medications were administered with an effective interval between doses versus 47% in 1997. Patient-controlled techniques were used in 28% of the cases in 1998 versus 9% in 1997.

CONCLUSION

The PQAP provided an improvement in efficacy of postoperative pain management in our unit, with the help of the overall ward staff, but without requiring personnel specially qualified.

Monitoring of end-tidal carbon dioxide partial pressure changes during infrarenal aortic cross-clamping: a non-invasive method to predict unclamping hypotension

BACKGROUND

To assess the variations in end-tidal CO2 in response to aortic cross-clamping and the relationship with systolic arterial pressure (SAP) changes induced by unclamping.

METHODS

Thirty-three patients undergoing infrarenal aortic abdominal aneurysm repair by aorto-aortic prothetic bypass were prospectively studied. All patients were anesthetized with i.v. midazolam (0.05 mg x kg(-1)), thiopentone (3-5 mg x kg(-1)), fentanyl (5 microg x kg(-1)), pancuronium (0.1 mg x kg(-1)) and the maintainance of anesthesia used was 1-1.5% end-tidal isoflurane and i.v. fentanyl. The perioperative management was standardized. End-tidal CO2 and SAP were measured 5 min before (Pre-XAA), 15 min after infrarenal aortic cross-clamping (XAA), 5 min before (Pre-UXAA) and immediately after unclamping (UXAA).

RESULTS

A total of 16 (48.5%) from 33 patients presented decrease in SAP following aortic unclamping, and 13 out of these patients had arterial hypotension defined as SAP<90 mmHg. End-tidal CO2 variation (PreXAA-PreUXAA) induced by aortic clamping was correlated with SAP variation (PreUXAA-UXAA) induced by unclamping (r=0.763; P=0.0001). An end-tidal CO2 reduction above 15% after aortic cross-clamping was found to have a 100% sensitivity to detect a SAP decrease greater than 20% after unclamping, with a 100% specificity and a negative predictive value of 1.0. Complete aortic occlusion duration was not correlated to SAP unclamping variation (deltaSAP). Intraoperative characteristics (fluid loading, hematocrits, urinary output) were comparable, although blood loss was higher in patients experiencing deltaSAP>20%.

CONCLUSIONS

End-tidal CO2 variation monitoring during aortic cross-clamping may provide a reliable and non-invasive method to predict unclamping hypotension. When the aortic clamp was released, systolic hypotension (>20%) occurred in those subjects who had a decrease in end-tidal CO2 greater than 15% during aortic cross-clamping.

Balloon dilation for aortic recoarctation: morphology at the site of dilation and long-term efficacy

OBJECTIVES

We undertook this study to assess the immediate and long-term outcome of balloon angioplasty performed for recurrent or residual coarctation of the aorta, and to assess the changes in the vessel wall caused by this procedure.

METHODS

Clinical, echocardiographic, angiographic and hemodynamic data from 71 patients who underwent balloon angioplasty for recoarctation between January 1987 and January 1998 were analysed retrospectively.

RESULTS

Angioplasty was performed after a median of 82.6 months (range 1.4 mo-20.9 y, mean 88.5 mo) following surgery for coarctation. Mean systolic pressure gradients were reduced from 27 +/- 15 mmHg to 11 +/- 11 mmHg after angioplasty (p < 0.0001). The mean diameter at the site of recoarctation increased from 5.5 +/- 2.5 to 7.5 +/- 2.7 mm (p < 0.0001). Outpouchings of contrast agents, indicating the disruption of the inner layers of the vessel wall, were defined as extravasations. They were observed in one-quarter of the angiograms performed immediately after the intervention. Immediate success of angioplasty was achieved in 71%, and persisted in 69% of patients during long-term follow up. The main determinant for immediate success was the age at the time of the procedure (p < 0.05), while the main determinant for long-term success was the increase achieved in diameter. Extravasations did not progress to aneurysms, neither acutely nor during echocardiographic follow-up studies. For further follow-up, more sensitive imaging techniques will be necessary to delineate the morphology of the site of extravasation observed immediately after angioplasty.

The emergency department experience of chest pain patients and their intention to delay care seeking for acute myocardial infarction

This study investigated how patients' emergency department experience was related to their intention to delay action in response to future symptoms of acute myocardial infarction. A sample of 426 persons admitted to the emergency department with a chief complaint of chest pain and released from the emergency department were contacted by telephone. Patients were queried about their affective response to the emergency department experience, their satisfaction with emergency department staff communication, their intention to delay prompt action for acute myocardial infarction symptoms in the future, the influence of others in the decision to seek care, and medical and demographic status. The results of a mixed model linear regression analysis showed that the less education patients had (p = 0.007), the less sure they felt that going to the emergency department had been "the right thing to do" (p = 0.004), and the greater the degree of embarrassment (p = 0.0001), the greater was the intention to delay action for future symptoms of acute myocardial infarction. The results also showed that those patients who were prompted by health professionals to go to the emergency department were less likely to report intentions to delay for future symptoms (p = 0.036). It is important that emergency department staff reassure chest pain patients who are sent home that they did the right thing by coming to the emergency department for their symptoms. Providers need to be particularly sensitive to feelings of embarrassment.

Clinical and neurophysiological study of the effects of multiple doses of artemisinin on brain-stem function in Vietnamese patients

The qinghaosu (artemisinin) group of drugs is the most important new class of antimalarials developed in the last fifty years. Although there has been no clinical evidence of neurotoxicity, an unusual pattern of damage to specific brain-stem nuclei has been reported in experimental animals receiving high doses of arteether or artemether. Detailed clinical examinations, audiometry, and brain stem auditory evoked potentials (BSAEPs) were assessed in 242 Vietnamese subjects who had previously received up to 21 antimalarial treatment courses of artemisinin or artesunate alone and 108 controls from the same location who had not received these drugs. There was no evidence of a drug effect on the clinical or neurophysiological parameters assessed. In this population there was no clinical or neurophysiological evidence of brain-stem toxicity that could be attributed to exposure to artemisinin or artesunate.

Age and sex differences in presentation of symptoms among patients with acute coronary disease: the REACT Trial. Rapid Early Action for Coronary Treatment

BACKGROUND

There are few data on possible age and sex differences in presentation of symptoms for patients with acute coronary disease.

OBJECTIVE

To investigate demographic differences in presentation of symptoms at the time of hospital presentation for acute myocardial infarction (AMI) and unstable angina.

METHODS

The medical records of patients who presented with chest pain and who also had diagnoses of AMI (n = 889) or unstable angina (n = 893) on discharge from 43 hospitals were reviewed as part of data collection activities of the Rapid Early Action for Coronary Treatment trial based in 10 pair-matched communities throughout the USA.

RESULTS

Dyspnea (49%), arm pain (46%), sweating (35%), and nausea (33%) were commonly reported by men and women of all ages in addition to the presenting complaint of chest pain. After we had controlled for various characteristics through regression modeling, older persons with AMI were significantly less likely than were younger persons to complain of arm pain and sweating, and men were significantly less likely to report vomiting than were women. Among persons with unstable angina, arm pain and sweating were reported significantly less often by elderly patients. Nausea and back, neck, and jaw pain were more common complaints of women.

CONCLUSIONS

Results of this study suggest that there are differences between symptoms at presentation of men and women, and those in various age groups, hospitalized with acute coronary disease. Clinicians should be aware of these differences when diagnosing and managing patients suspected to have coronary heart disease.

Cell cycle restriction of telomere elongation

Telomere elongation by telomerase balances the progressive shortening of chromosome ends due to the succession of replication cycles [1] [2]. Telomerase activity is regulated in vivo at its site of action by the telomere itself. In yeast and human cells, the mean telomere length is maintained at a constant value through a cis-inhibition of telomerase by factors specifically bound to the telomeric DNA [3] [4] [5] [6] [7]. Here, we address an unexplored aspect of telomerase regulation by testing the link between telomere dynamics and cell cycle progression in the budding yeast Saccharomyces cerevisiae. We followed the elongation of an abnormally shortened telomere and observed that, like telomere shortening in the absence of telomerase, telomere elongation is linked to the succession of cell divisions. In cells progressing synchronously through the cell cycle, telomere elongation coincided with the time of telomere replication. On a minichromosome, a replication defect partially suppressed telomere elongation, suggesting a coupling between in vivo telomerase activity and conventional DNA replication.

Regulation of cytokinesis by the Elm1 protein kinase in Saccharomyces cerevisiae

A Saccharomyces cerevisiae mutant unable to grow in a cdc28-1N background was isolated and shown to be affected in the ELM1 gene. Elm1 is a protein kinase, thought to be a negative regulator of pseudo-hyphal growth. We show that Cdc11, one of the septins, is delocalised in the mutant, indicating that septin localisation is partly controlled by Elm1. Moreover, we show that cytokinesis is delayed in an elm1delta mutant. Elm1 levels peak at the end of the cell cycle and Elm1 is localised at the bud neck in a septin-dependent fashion from bud emergence until the completion of anaphase, at about the time of cell division. Genetic and biochemical evidence suggest that Elm1 and the three other septin-localised protein kinases, Hsl1, Gin4 and Kcc4, work in parallel pathways to regulate septin behaviour and cytokinesis. In addition, the elm1delta;) morphological defects can be suppressed by deletion of the SWE1 gene, but not the cytokinesis defect nor the septin mislocalisation. Our results indicate that cytokinesis in budding yeast is regulated by Elm1.

Involvement of the PP2C-like phosphatase Ptc2p in the DNA checkpoint pathways of Saccharomyces cerevisiae

RAD53 encodes a conserved protein kinase that acts as a central transducer in the DNA damage and the DNA replication checkpoint pathways in Saccharomyces cerevisiae. To identify new elements of these pathways acting with or downstream of RAD53, we searched for genes whose overexpression suppressed the toxicity of a dominant-lethal form of RAD53 and identified PTC2, which encodes a protein phosphatase of the PP2C family. PTC2 overexpression induces hypersensitivity to genotoxic agents in wild-type cells and is lethal to rad53, mec1, and dun1 mutants with low ribonucleotide reductase activity. Deleting PTC2 specifically suppresses the hydroxyurea hypersensitivity of mec1 mutants and the lethality of mec1Delta. PTC2 is thus implicated in one or several functions related to RAD53, MEC1, and the DNA checkpoint pathways.

[Impact of an information booklet on patient satisfaction in anesthesia]

OBJECTIVE

The aim of this study was to evaluate the satisfaction of adult surgical patients before and after an information booklet concerning anaesthetic techniques and complications, and postoperative management has been proposed during preanaesthetic visits.

STUDY DESIGN

Survey.

METHOD

Three surveys have been performed using an anonymous questionnaire of 25 items with graduated answers (very good, good, bad, very bad, no opinion) concerning patient satisfaction on structure, physician behavior, information and well being. As the results of the first two surveys were not significantly different, an information booklet was proposed to patients during preanaesthetic visits, then a third survey ("After") was realized. The results of this survey were compared to the combined results of the first two surveys ("Before").

RESULTS

In the "before" survey, 60 to 76% of the patients were satisfied (very good and good) of the information delivered during preanaesthetic visits. The proportion of patients satisfied of the information concerning anaesthetic techniques, transfusion and recovery were significantly higher in the "after" survey (P < 0.05).

CONCLUSION

An information booklet on anaesthesia increases patient satisfaction on information provided during preanaesthetic visits.

The risk of cardiac injury during laparoscopic fundoplication: cardiac troponin I and ECG study

BACKGROUND

Myocardial trauma has been described during gastroesophageal reflux laparoscopic surgery, in association with the proximity of cardiac structures. In addition, specific haemodynamic changes induced by CO2 pneumoperitoneum could exacerbate perioperative cardiac complication even in patients without cardiac risk factors. The aim of this study was to evaluate the influence of gastroesophageal reflux laparoscopic surgery on the perioperative ECG, cardiac troponin I and myocardial enzyme changes.

METHODS

Forty-two ASA I-II patients without ischaemic heart disease or combined double-risk factors were studied. Automated ST segment analysis was used intraoperatively. ECG, plasma myocardial enzyme and cardiac troponin I concentrations were reported on arrival in the recovery room (HO), 4 h (H4) and 24 h (H24) postoperatively.

RESULTS

Intraoperative ST segment changes occurred in two patients: the first during a hypotensive episode (MAP<55 mmHg; 3/42 patients) and the second during a hypertensive episode (MAP >110 mmHg; 3/42 patients). One case of intraoperative subcutaneous emphysema occurred without ST disturbance. One case of pneumothorax was observed at H0-H4 in another patient without clinical symptoms. Cardiac troponin I and CK-MB were not increased postoperatively. Transaminase concentrations increased (2-fold normal values) in 26/42 patients. In these 26 patients, 7 experienced 5-fold isolated transaminase increase, associated with left hepatic artery section.

CONCLUSION

According to perioperative ECG changes and/or specific cardiac troponin I measurements, we did not identify specific myocardial damage following gastroesophageal reflux laparoscopic surgery. Unexpectedly, the incidence of hepatic cytolysis was frequent (62%) and has not previously been reported in the literature.

The history of thoracic surgical instruments and instrumentation

Thoracic surgical practice has evolved from the innovations of its pioneers. Beginning with the stethoscope discovered by Laënnec with his system of auscultation, to the tools we use in the dissection and control of the hilum of the lung for resection, our practice of thoracic surgery has been entwined with the development of instruments and instrumentation. The development of strategies to prevent death from the open pneumothorax began with manual control of the mediastinum and progressed through differential pressure to, finally, the technique of intubation and the methods of positive-pressure and insufflation anesthesia. The instruments we place in our hands are not enough to define our art. Entry into the chest would not be possible without the use of rib retractors, rib shears, and even periosteal elevators. Finally, to the present day of minimally invasive techniques and the application of thoracoscopy for therapeutic purposes, we find the efforts of our predecessors well developed. For the progression from the fear of the open pneumothorax to the present-day state of the ease of thoracotomy for lung resection we are indebted to those who gave so much of their time and, for some, their lives to death from tuberculosis, to allow the advancement of our practice of surgery. These great people should be remembered not only for their acceptance of novel ideas but also, more importantly, for their lack of fear of testing them.

Tractional force generation by porcine Müller cells: paracrine stimulation by retinal pigment epithelium

PURPOSE

To examine the ability of retinal pigment epithelial (RPE) cells to modulate Müller cell extracellular matrix contraction through secreted promoters.

METHODS

Freshly isolated RPE cells were maintained in continuous culture until the morphologic and immunocytochemical changes associated with myofibroblastic dedifferentiation were complete. Secretory products collected from these cells during extended incubations in serum-free medium and at different stages of dedifferentiation were examined for the ability to promote extracellular matrix contraction by Müller cells. The contributions of specific growth factors to RPE-secreted activity were examined with growth factor-neutralizing antibodies.

RESULTS

Secretory products from RPE cells throughout dedifferentiation contained biologically active quantities of Müller cell contraction promoters. Secretory activity increased during extended incubation in serum-free medium and during myofibroblastic dedifferentiation. Growth factor-specific neutralizing antibodies enabled the determination that insulin-like growth factor- and platelet-derived growth factor-related proteins were the secreted species to which Müller cells responded. Finally, gene expression of insulin-like growth factor 1 and platelet-derived growth factor A chain by porcine RPE cells was confirmed using reverse transcription-polymerase chain reaction. CONCLUSIONS. RPE cells are a viable source of biologically active quantities of two growth factors that stimulate extracellular matrix contraction by Müller cells. This secretory profile persists for extended periods in an otherwise serum-free environment and is enhanced during myofibroblastic dedifferentiation.

Comparison of intravenous or epidural patient-controlled analgesia in the elderly after major abdominal surgery

BACKGROUND

Patient-controlled analgesia (PCA) with intravenous morphine and patient-controlled epidural analgesia (PCEA), using an opioid either alone or in combination with a local anesthetic, are two major advances in the management of pain after major surgery. However, these techniques have been evaluated poorly in elderly people. This prospective, randomized study compared the effectiveness on postoperative pain and safety of PCEA and PCA after major abdominal surgery in the elderly patient.

METHODS

Seventy patients older than 70 yr of age and undergoing major abdominal surgery were assigned randomly to receive either combined epidural analgesia and general anesthesia followed by postoperative PCEA, using a mixture of 0.125% bupivacaine and sufentanil (PCEA group), or general anesthesia followed by PCA with intravenous morphine (PCA group). Pain intensity was tested three times daily using a visual analog scale. Postoperative evaluation included mental status, cardiorespiratory and gastrointestinal functions, and patient satisfaction scores.

RESULTS

Pain relief was better at rest (P = 0.001) and after coughing (P = 0.002) in the PCEA group during the 5 postoperative days. Satisfaction scores were better in the PCEA group. Although incidence of delirium was comparable in the PCA and PCEA groups (24% vs. 26%, respectively), mental status was improved on the fourth and fifth postoperative days in the PCEA group. The PCEA group recovered bowel function more quickly than did the PCA group. Cardiopulmonary complications were similar in the two groups.

CONCLUSION

After major abdominal surgery in the elderly patient, patient-controlled analgesia, regardless of the route (epidural or parenteral), is effective. The epidural route using local anesthetics and an opioid provides better pain relief and improves mental status and bowel activity.

A case-control auditory evaluation of patients treated with artemisinin derivatives for multidrug-resistant Plasmodium falciparum malaria

The artemisinin derivatives are now used widely in areas with multidrug-resistant Plasmodium falciparum malaria such as Southeast Asia, but concerns remain over their potential for neurotoxicity. Mice, rats, dogs, and monkeys treated with high doses of intramuscular artemether or arteether develop an unusual pattern of focal damage to brain stem nuclei (particularly those involved in auditory processing). To investigate whether a similar toxic effect occurs in patients treated with these compounds, clinical neurologic evaluation, audiometry and early latency auditory evoked responses were measured in a single-blind comparison of 79 patients who had been treated with > or =2 courses of oral artemether or artesunate within the previous 3 years, and 79 age- and sex-matched controls living in a malaria-endemic area on the northwestern border of Thailand. There were no consistent differences in any of these test results between the cases and controls. This study failed to detect any evidence of significant neurotoxicity in patients treated previously with oral artemether or artesunate for acute malaria.

Interleukin-10 (IL10) promoter polymorphisms and multiple sclerosis

Interleukin-10 (IL10) is an anti-inflammatory cytokine which may modulate disease expression in multiple sclerosis (MS). Three dimorphic polymorphisms within the IL10 promoter region at positions - 1082, -819 and -519 have previously been identified. The - 1082*A allele has been associated with low and the - 1082*G allele with high in vitro IL10 production. We have genotyped 185 Caucasian MS patients and 211 ethnically matched controls for each of these three dimorphisms. MS patients were stratified for severity of disease outcome. No associations were found for any IL10 promoter polymorphisms when the MS cases were compared with controls or with disease outcome with regards to disability. IL10 polymorphism does not appear to be associated with MS or to influence disease progression.

The relationship among carbon dioxide pneumoperitoneum, vasopressin release, and hemodynamic changes

We assessed the role of vasopressin (VP) for the hemodynamic response to pneumoperitoneum in pigs. Four groups of anesthetized pigs were investigated. Nine pigs were intraabdominally insufflated with CO2 and eight were intraabdominally insufflated with argon; eight pigs received an i.v. injection of 1 mg/kg SR 49059, a VP antagonist, before CO2 insufflation; and six pigs received SR 49059 alone. Hemodynamics, plasma concentrations of VP and vasoactive hormones, and Paco2 were measured. Data were analyzed by using analysis of variance, Student's t-test, and Mann-Whitney U-test. Five minutes after insufflation, changes in systemic vascular resistance (SVR) were significantly correlated with changes in VP (r = 0.72; P = 0.005) but not with changes in epinephrine, norepinephrine, renin activity, or Paco2. SVR increased during CO2 insufflation but not during argon insufflation or CO2 insufflation with a preceding infusion of SR 49059. The SR 49059 injection itself resulted in increases in heart rate and cardiac output and decreases in blood pressure and SVR. We conclude that, during CO2 pneumoperitoneum in pigs, absorbed CO2 initiates a pathophysiological process that stimulates VP release. Hence, VP most likely plays a key role in the hemodynamic response to a CO2-induced pneumoperitoneum.

IMPLICATIONS

Intraabdominal insufflation of CO2 is associated with hemodynamic and hormonal changes. Investigating CO2 and argon-insufflated pigs and using a vasopressin antagonist, we found that CO2 insufflation released vasopressin, which, in turn, induced hemodynamic perturbances.

Saccharomyces cerevisiae MPS2 encodes a membrane protein localized at the spindle pole body and the nuclear envelope

The MPS2 (monopolar spindle two) gene is one of several genes required for the proper execution of spindle pole body (SPB) duplication in the budding yeast Saccharomyces cerevisiae (). We report here that the MPS2 gene encodes an essential 44-kDa protein with two putative coiled-coil regions and a hydrophobic sequence. Although MPS2 is required for normal mitotic growth, some null strains can survive; these survivors exhibit slow growth and abnormal ploidy. The MPS2 protein was tagged with nine copies of the myc epitope, and biochemical fractionation experiments show that it is an integral membrane protein. Visualization of a green fluorescent protein (GFP) Mps2p fusion protein in living cells and indirect immunofluorescence microscopy of 9xmyc-Mps2p revealed a perinuclear localization with one or two brighter foci of staining corresponding to the SPB. Additionally, immunoelectron microscopy shows that GFP-Mps2p localizes to the SPB. Our analysis suggests that Mps2p is required as a component of the SPB for insertion of the nascent SPB into the nuclear envelope.