Effectiveness of intravenous magnesium sulfate to attenuate hemodynamic changes in laparoscopic surgery: a systematic review and meta-analysis.

Objective: The purpose of this systematic review and meta-analysis was to determine the effectiveness of intravenous magnesium sulfate when used to attenuate hemodynamic fluctuations associated with the creation of pneumoperitoneum in adults undergoing laparoscopic surgery.

Introduction: Laparoscopic surgery has gained popularity as a result of improved patient outcomes postoperatively, but pneumoperitoneum alters the patient's physiology and hemodynamic profile during the intraoperative period. Magnesium sulfate is a nonopioid agent known for its ability to blunt the physiologic sympathetic response associated with exposure to noxious stimuli.

Intravenous magnesium sulfate to attenuate hemodynamic changes in laparoscopic surgery: a systematic review protocol.

Objective: The objective of this systematic review is to determine the efficacy of intravenous magnesium sulfate when used to attenuate hemodynamic fluctuations associated with the creation of pneumoperitoneum in adults undergoing laparoscopic surgery.

Introduction: Laparoscopic surgery has gained popularity as a result of improved patient outcomes postoperatively, but pneumoperitoneum alters the patient's physiology and hemodynamic profile during the intraoperative period. Magnesium sulfate is a non-opioid agent known for its ability to blunt the physiologic sympathetic response associated with exposure to noxious stimuli.

Transbronchial biopsy in the presence of profound elevation of the international normalized ratio.

Study Objective: To identify a level of coagulopathy, reported as the international normalized ratio (INR), that predicts hemorrhage following transbronchial forceps biopsy (TBBx) in an animal model.

Design: Crossover blinded study using Yucatan mini-swine (Sus scrofa).

Setting: Tertiary medical center with a dedicated animal research facility.

Oral anticoagulant therapy and international normalized ratios in swine.

While monitoring coagulation testing in Yucatan miniature swine being given oral anticoagulants, we noticed instances of high international normalized ratios (INR) without clinical complications in our animal model. All pigs (n = 17) weighed approximately 35.2 kg and were dosed daily with 2 to 3 mg of coumadin.

A structural basis for substrate specificities of protein Ser/Thr kinases: primary sequence preference of casein kinases I and II, NIMA, phosphorylase kinase, calmodulin-dependent kinase II, CDK5, and Erk1.

We have developed a method to study the primary sequence specificities of protein kinases by using an oriented degenerate peptide library. We report here the substrate specificities of eight protein Ser/Thr kinases. All of the kinases studied selected distinct optimal substrates.

Comparison of quantitative cultures to semiquantitative loop cultures of bronchoscopic protected specimen brush samples.

Study Objective: To compare quantitative growth from a calibrated loop to growth from the standard serial dilution technique of culturing bronchoscopic protected specimen brush (PSB) samples and to determine the effect of refrigeration of the PSB sample on subsequent quantitative growth.

Design: Laboratory stock cultures were sampled with a PSB and cultured by both standard 100-fold serial dilution as well as 1:100 mL and 1:1,000 mL calibrated loops. Stock cultures were also sampled with a PSB and growth before and after refrigeration for 24 h at 4 degrees C (both serial dilution and calibrated loops) was compared.

Isolation and characterization of glycogen synthase in Dictyostelium discoideum.

We have partially purified the protein and isolated the glcS gene for glycogen synthase in Dictyostelium. glcS mRNA is present throughout development and is the product of a single gene coding for 775 amino acids, with a predicted molecular mass of 87 kD. The sequence is highly similar to glycogen synthase from human muscle, yeast, and rat liver, diverging significantly only at the amino and carboxy termini.

Identification of a Ca2+/calmodulin-dependent protein kinase II regulatory phosphorylation site in non-N-methyl-D-aspartate glutamate receptors.

Glutamate receptor ion channels are colocalized in postsynaptic densities with Ca2+/calmodulin-dependent protein kinase II (CaM-kinase II), which can phosphorylate and strongly enhance non-N-methyl-D-aspartate (NMDA) glutamate receptor current. In this study, CaM-kinase II enhanced kainate currents of expressed glutamate receptor 6 in 293 cells and of wild-type glutamate receptor 1, but not the Ser-627 to Ala mutant, in Xenopus oocytes. A synthetic peptide corresponding to residues 620-638 in GluR1 was phosphorylated in vitro by CaM-kinase II but not by cAMP-dependent protein kinase or protein kinase C.

Obstructed tracheal bronchus as a cause of post-obstructive pneumonia.

This article describes a case of obstructed supernumerary tracheal bronchus with partial atelectasis and pneumonia of the right upper lobe, diagnosed using trispiral tomograms. An obstructing broncholith, a supernumerary tracheal bronchus, and granulation tissue mass extruding from the bronchus were confirmed by resection of the pulmonary segment.

Mutational analysis of the autoinhibitory domain of calmodulin kinase II.

Calmodulin (CaM)-kinase II is inactive in the absence of Ca2+/CaM due to interaction of its autoinhibitory domain with its catalytic domain. Previous studies using synthetic autoinhibitory domain peptides (residues 281-302) identified several residues as important for inhibitory potency and suggested that His282 may interact with the ATP-binding motif of the catalytic domain. To further examine the autoinhibitory domain, site-specific mutants were expressed using the baculovirus/Sf9 cell system.

Activation mechanisms for Ca2+/calmodulin-dependent protein kinase IV. Identification of a brain CaM-kinase IV kinase.

This manuscript examines the mechanisms by which Ca2+/calmodulin-dependent protein kinase IV (CaM-kinase IV) is activated through the binding of Ca2+/CaM and by phosphorylation. Studies with the synthetic autoinhibitory domain peptides of CaM-kinase II indicate that CaM-kinase IV has a similarly located autoinhibitory domain, and this was confirmed since site-directed mutagenesis of this region (HMDT308 to DEDD and FN317 to DD) generated fully active Ca2+/CaM-independent kinases. Total activities of purified, baculovirus-expressed wild type and mutant kinases were increased 2-fold by intramolecular autophosphorylation, but this reaction was extremely slow (1-2 h) and probably not physiological.

Alpha subunit of calcium/calmodulin-dependent protein kinase enhances excitatory amino acid and synaptic responses of rat spinal dorsal horn neurons.

1. Here we report that in acutely isolated rat spinal dorsal horn (DH) neurons, the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)/kainate and N-methyl-D-aspartate (NMDA) receptors can be regulated by endogenous and exogenous calcium/calmodulin-dependent protein kinase II (CaM-KII). Intracellularly applied, the alpha-subunit of CaM-KII enhanced AMPA/kainate and NMDA currents recorded with the use of the whole cell patch-clamp technique.

Mutational analysis of secondary structure in the autoinhibitory and autophosphorylation domains of calmodulin kinase II.

A previous study has suggested that the autoinhibitory domain of Ca2+/calmodulin-dependent protein kinase II (CaM-kinase II) may contain an alpha-helical structure, which is important for the proper orientation of inhibitory residues to interact with the catalytic domain (Smith, M. K., Colbran, R.

Characterization of Ca2+/calmodulin-dependent protein kinase IV. Role in transcriptional regulation.

We have characterized Ca2+/calmodulin-dependent protein kinase IV (CaM kinase IV), expressed using the baculovirus/Sf9 cell system, to assess its potential role in Ca2+-dependent transcriptional regulation. CaM kinase IV was strongly inhibited in vitro by KN-62, a specific CaM kinase inhibitor which suppresses Ca2+-dependent transcription of several genes, so we tested whether CaM kinase IV could stimulate transcription. Co-transfection of COS-1 cells by cDNA for CaM kinase IV gave 3-fold stimulation of a reporter gene expression, whereas co-transfection with CaM kinase II gave no transcriptional stimulation.

Surgical management of hyperparathyroidism at an Air Force medical center.

A critical determinant of successful neck exploration for primary hyperparathyroidism (HPT) is the experience of the surgeon. Results of 17 patients treated surgically for HPT were reviewed to compare results at our medical center with results of large series reported from established national centers. Preoperative laboratory evaluation of 15 patients with surgically proven HPT (solitary adenoma, 14; diffuse hyperplasia, 1) included: mean serum calcium (Ca) 10.

Phosphorylation and regulation of glutamate receptors by calcium/calmodulin-dependent protein kinase II.

The major postsynaptic density (PSD) protein at glutaminergic synapses is calcium/calmodulin-dependent protein kinase II (CaM-K II), but its function in the PSD is not known. We have examined glutamate receptors (GluRs) as substrates for CaM-K II because (1) they are colocalized in the PSD, (2) cloned GluRs contain consensus phosphorylation sites for protein kinases including CaM-K II, and (3) several GluRs are regulated by other protein kinases. Regulation of GluRs, which are involved in excitatory synaptic transmission and in mechanisms of learning and memory, by CaM-K II is of interest because of the postulated role of CaM-K II in synaptic plasticity and its known involvement in induction of long-term potentiation.

Characterization of the phosphatase activity of a baculovirus-expressed calcineurin A isoform.

Calcineurin A was purified by calmodulin-Sepharose affinity chromatography from Sf9 cells infected with recombinant baculovirus containing the cDNA of a rat calcineurin A isoform. The Sf9-expressed calcineurin A has a low basal phosphatase activity in the presence of EDTA (0.9 nmol/min/mg) which is stimulated 3-5-fold by Mn2+.

Functional determinants in the autoinhibitory domain of calcium/calmodulin-dependent protein kinase II. Role of His282 and multiple basic residues.

Important determinants in the autoinhibitory domain of calcium/calmodulin-dependent protein kinase II (CaMK-II), corresponding to residues 281-302 of the kinase alpha-subunit sequence, were identified. Replacement of Thr286 with Ala (CaMK-(281-302 Ala286)) had no effect on either the potency (IC50 = 2 MicroM) or inhibitory mechanism (competitive with ATP) using the catalytic fragment of CaMK-II. Single replacement of charged residues in CaMK-(281-302, Ala286) identified His282, Arg283, Lys291, Arg297, and Lys298 as important determinants (greater than 10-fold increase in IC50) for potent inhibition of CaMK-II.

Expression and characterization of the alpha-subunit of Ca2+/calmodulin-dependent protein kinase II using the baculovirus expression system.

Sf9 cells infected with the recombinant mouse CaMKII-alpha (Ca2+/calmodulin dependent kinase II) baculovirus expressed 12-15 mg of MCaMKII-alpha per liter of cells. Approximately 50% of the MCaMKII-alpha activity could be purified using a CaM-Sepharose affinity column. The purified MCaMKII-alpha had a M(rapp) of 50 kDa by SDS-PAGE and a native Mr of 600 kDa.

Regulation of the two forms of glycogen phosphorylase by cAMP and its analogs in Dictyostelium discoideum.

We have recently reported the existence of two forms of glycogen phosphorylase (1,4-alpha-D-glucan: orthophosphate-alpha-glucosyltransferase; EC 2.4.1.

Glycogen phosphorylase 'b' in Dictyostelium: stability and endogenous phosphorylation.

The slime mold Dictyostelium discoideum has two forms of the enzyme glycogen phosphorylase. The inactive phosphorylase 'b' form requires 5' AMP for activity and is present in early development. The active phosphorylase 'a' form is 5' AMP independent and occurs during later development.

The relationship between the two forms of glycogen phosphorylase in Dictyostelium discoideum.

The cellular slime mold, Dictyostelium disoideum, provides an ideal model system to study eukaryotic cell differentiation. In D. discoideum, glycogen degradation provides precursors for the synthesis of developmentally regulated structural products.