Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.59 (MIP)
 4,906 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The specific aspects of the respiratory cycle during mechanical ventilation that allow for optimum gas exchange are still controversial. To further clarify the relationship of inspiratory:expiratory ratio and positive end expiratory pressure to optimum ventilation and oxygenation, five premature lambs with severe hyaline membrane disease were ventilated with volume-present infant ventilators at I:E ratios of 1:4 and 1:1 and PEEP levels of 0, 5, and 10 cm H2O. For each I:E ratio/PEEP combination, pH, Pao2, PaCO2, PAO2, PACO2, peak inspiratory pressure, mean inspiratory pressure, and mean airway pressure were measured and compared. Optimum ventilation and oxygenation were related to MAP, but not to I:E ratio, PIP, or MIP. As MAP increased from 6 to 14 cm H2O, progressive improvement in Pao2, PaCO2 (A-a) DO2 and (a-A) DCO2 was evident. Above 14 cm H2O, there was progressive deterioration in these measurements. There was also a direct relationship between MAP and mean pleural pressure. These results indicate that during mechanical ventilation there is an optimum MAP at which gas exchange is best. Since MAP changes with any change in PIP, PEEP, or I:E ratio, it provides a useful composite measure of all pressures transmitted to the airways by the ventilator.
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PMID:The effect of independent variations in inspiratory-expiratory ratio and end expiratory pressure during mechanical ventilation in hyaline membrane disease: the significance of mean airway pressure. 33 78

The maximal pressure that can be generated during an inspiratory effort against an occluded airway serves as an index of respiratory muscle strength. We devised a method that permits accurate measurement of MIP, with near maximal values, and does not require patient cooperation. Twenty-two critically ill intubated patients performed MIP maneuvers before and after coaching. For the initial 11 patients, MIP was measured after the airway was occluded in 20 s with a one-way valve that permitted only exhalation. In the latter 11 patients, DS (approximately 1/3 VT) was added in an effort to increase respiratory drive before the noncoached MIP maneuver. We found no significant difference between coached and noncoached MIP maneuvers when P0.1 during the first 100 ms of inspiratory efforts prior to the noncoached MIP maneuver was greater than 2 cm H2O. Thus, MIP can be reliably measured in critically ill patients with or without coaching.
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PMID:Validation of a technique to assess maximal inspiratory pressure in poorly cooperative patients. 139 71

Certain cytokines such as tumor necrosis factor (TNF) and interleukin-1 (IL-1) act centrally to affect eating behavior and thermoregulation and may be involved in the physiological mechanisms leading to anorexia, adipsia and loss in body weight. The newly discovered macrophage inflammatory protein-1 (MIP-1) infused into the anterior hypothalamic, preoptic area (AH/POA) evokes an intense hyperthermia. The present experiments were designed to determine whether MIP-1 affects the feeding mechanism in the ventromedial hypothalamus (VMH) independently of the thermoregulatory mechanism in the AH/POA. For the microinjection of MIP-1, guide cannulae were implanted stereotaxically in the rat just above the VMH or AH/POA. Following postoperative recovery, each unrestrained rat was adapted to procedures whereby body temperature and intakes of food and water available ad lib were monitored at predetermined intervals. When an efficacious dose of 5.6 picograms (pg) MIP-1 was microinjected in a volume of 0.5 microliters into the VMH, the intake of food in the rat was reduced significantly in the short term and throughout the following 22 h. Within intervals of 30 min and 4.0 h following MIP-1, the amount of food consumed was 4.0 and 10 g, respectively, below that eaten by control rats given the saline solvent vehicle injected at the same site in the VMH. Over the entire test period, the intake of water was similarly significantly below that of the control rats. Whereas MIP-1 injected into the AH/POA evoked fever accompanied by a transient decline in feeding, the body temperature of the rats was unaffected by the cytokine injected in the VMH.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Anorexia and adipsia: dissociation from fever after MIP-1 injection in ventromedial hypothalamus and preoptic area of rats. 174 16

We have compared the long-term developmental changes in water-insoluble protein expression by chick lens cells in vitro and in vivo. Crude membrane fractions were prepared by alkali treatment of the urea-insoluble protein fraction, and the proteins analysed by sodium dodecyl sulphate-polyacrylamide (SDS-PAGE) gel electrophoresis. The major component present in the urea-insoluble fraction of chick lens fibres, a 25,000 MW polypeptide (MIP-25K) was more abundant in adult (8 weeks) than day-old post-hatch chick lens fibre masses. MIP-25K was detected in differentiated but not predifferentiated lens cell cultures, and indirect immunofluorescence using anti-bovine MIP antiserum indicated that MIP-25K was localized in the lentoid bodies. Our findings indicate that the urea-insoluble protein profiles of long-term well-differentiated chick lens cell cultures are qualitatively very similar to the profiles of the lens fibres. The data also confirm that the expression of MIP-25K, rather than the expression of water-soluble crystallin protein, is a marker for lens cell differentiation, and confirm earlier reports, which have been disputed, that delta-crystallin (but not alpha-or beta-crystallin) is specifically associated with chick lens fibre membranes.
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PMID:Developmental changes in membrane protein expression by chick lens cells in vivo and in vitro and the detection of main intrinsic polypeptide (MIP). 308 28

Ab initio molecular orbital studies have been made as a model for the deacylation step of trypsin. Ser-195 is modeled by H2O in which one H is replaced either by--PO2(OH)- (monoisopropyl phosphoryl, MIP) or by--CHO(OH)- (a transition state analogue, TSD). The quantum mechanical region includes imidazole+ and acetate- as models for His-57+ and Asp-102-, two hydrogen bonds from two formamide molecules to the oxyanion MIP or TSD, and three hydrogen bonds to Asp-102. The remainder of the enzyme is treated classically as a fractional charge model. The effect of proton transfer from His-57+ to Asp-102- is very similar for the MIP and TSD models, and the proton transfer is energetically unfavorable for all models that include at least the hydrogen bond from an H2O that models Ser-214. Thus, the several hydrogen bonds to the models of the catalytic unit (substrate, Ser-195, His-57, and Asp-102) stabilize the His-57+/Asp-102- salt link, and this indicates that proton transfer does not occur from His-57+ to Asp-102-. (Also, the similarities of energy of transfer of this proton transfer for the various models show that the model substrate analogue behaves very similarly to the MIP inhibitor.)
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PMID:Charge state of His-57-Asp-102 couple in a transition state analogue-trypsin complex: a molecular orbital study. 609 93

The measurement of maximal inspiratory and expiratory pressures at the mouth (MIP and MEP, respectively) provides a noninvasive clinical method for evaluating the strength of respiratory muscles. In an attempt to reconcile the widely divergent normal values reported in the literature for healthy adolescents, we have measured, using simple manometry, MIP and MEP in 112 white subjects, 76 adolescents and 36 healthy adults. For female adolescents the values for MIP and MEP were 76 +/- 25 and 86 +/- 22 cm H2O, respectively, and were significantly less than those for male adolescents (p less than 0.01), whose mean values were 107 +/- 26 and 114 +/- 35 cm H2O, respectively. Mean values for adolescents were comparable to values measured in adult control subjects, and for both adolescents and adults, mean values approximated the lower end of the previously reported ranges of normal values in healthy subjects. Thus, MIP and MEP in healthy adolescents are significantly greater in male subjects than female subjects, but are comparable to those of healthy adults of the same sex. Furthermore, these studies suggest that the choice of normal values for MIP and MEP must take into account significant methodologic differences among laboratories.
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PMID:Maximal inspiratory and expiratory pressures in adolescents. Normal values. 647 96

Cardiovascular responses during hyperinflation produced by positive end-expiratory pressure (PEEP) are considered to be reflexly influenced by pulmonary mechanoreceptors. Numerous studies have indicated heart and vascular effects attributed to mechanical events and cardiopulmonary mechanoreflexes. Yet interactions of these modalities with the systemic baroreflexes are not clear. We examined aspects of these modulatory interactions by distinguishing changes in pulmonary, heart, and vascular responses during PEEP-hyperinflation before and after progressive elimination of chemo-, mechano-, and baroreflex influences in the closed-chest anesthetized rabbit. During respiratory alkalosis PEEP was imposed in increments of 2.5 cm H2O (range 0.0 to 7.5 cm H2O) before and during control of carotid intrasinus pressure and following aortic denervation and vagotomy. Heart rate responses during PEEP increased prior to aortic denervation, decreased following elimination of baroreflexes, and were abolished after vagotomy. The fall in mean arterial pressure (MAP) during PEEP was accentuated during elimination of the baroreflexes and ameliorated following vagotomy. Mean right atrial (MRAP), intrapleural (MIP), and right atrial transmural pressure increased during PEEP prior to vagotomy. Regression analyses of MAP versus MRAP and MAP versus MIP suggest that vagally receptors reflexly influence venous as well as systemic arterial vascular pressure. Conclusion indicate that when superimposed on mechanical events, cardiopulmonary mechanoreceptors and arterial baroreceptors effect conflicting facilitory reflex influences on heart and vascular responses during PEEP-hyperinflation.
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PMID:Altered cardiovascular reflex responses during positive pressure breathing. 701 95

Two recently cloned water channels, CHIP28 and WCH-CD, are homologous to MIP26, an integral membrane channel-forming protein found in lens fiber plasma membranes. CHIP28 is found in basolateral and apical plasma membranes of kidney proximal tubules and thin descending limbs of Henle, whereas WCH-CD is apically located in collecting duct principal cells. So far, the putative water channel that may be responsible for the high constitutive permeability of principal cell basolateral membranes has not been identified. Interestingly, freeze-fracture electron microscopy has shown that characteristic orthogonal arrays of intramembrane particles (OAPs) are found on the basolateral plasma membranes of collecting duct principal cells, and that morphologically identical OAPs present in lens fiber cell plasma membranes contain the protein MIP26. Similar OAPs have also been detected on plasma membranes of other cell types including gastric parietal cells, astroglial cells and skeletal muscle fibers. By indirect immunofluorescence, western blotting and northern blotting, MIP26 was found only in lens fibers. In addition, functional studies on reconstituted and oocyte-expressed MIP26 excluded the possibility that MIP26 might be a basolateral water channel in the kidney. However, a polyclonal antibody raised against skeletal muscle sarcolemmal vesicles, which are enriched in OAPs, produced an intense staining of principal cell basolateral plasma membranes in kidney collecting duct and immunoprecipitated a 28 kDa protein from kidney papilla. The immunoprecipitated protein from papilla was not recognized by anti-CHIP28 or anti-MIP26 antibodies, indicating that principal cell basolateral membranes contain a novel member of the CHIP/MIP family. Because this antibody also stained brain astrocyte end feet, which are enriched in OAPs, it is possible that the 28 kDa protein is related to these structures. We conclude that OAPs probably contain related but distinct proteins that may have different membrane channel functions in different cell types.
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PMID:A 28 kDa sarcolemmal antigen in kidney principal cell basolateral membranes: relationship to orthogonal arrays and MIP26. 752 41

According to our previous studies the Arabidopsis gene AthH2 which is inducible by blue light and phytohormones codes for an intrinsic membrane protein. It bears a resemblance to several distinct channel proteins of plant and animal species classified as the MIP/NOD-26/GlpF family. In the present study biochemical analyses and electron microscopic immunochemistry were used to elucidate the subcellular location of the AthH2 protein. The results clearly demonstrate that it is an exclusive constituent of the plasmalemma. Furthermore, the expression of the AthH2 gene in transgenic Arabidopsis plants containing the promoter region of AthH2 fused to the beta-glucuronidase (gus) reporter gene was studied. The in situ localization of gus activity revealed that the specific promoter is temporally activated by light in expanding and/or differentiating cells comprising newly formed tissues and organs: root elongation zone, guard cells of stomata, vascular bundle sheaths, filaments of stamen and young siliques. Several sites of gus expression coincide spatially with those of in situ hybridization and the immunocytochemical reaction, respectively, suggesting that the AthH2 promoter had correctly responded to light as an important exogenous factor with relevance to the complex pattern of differentiation. Studies with protoplasts from plants transformed with an antisense construct revealed a water transport capacity of the AthH2 protein.
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PMID:The blue light-responsive AthH2 gene of Arabidopsis thaliana is primarily expressed in expanding as well as in differentiating cells and encodes a putative channel protein of the plasmalemma. 753 55

17 members of MIP family from bacteria, yeast, plants and animals are compared in this review. These proteins appear to function in (1) water channels (CHIP, WCH-CD, MIWC, AQP3, gTIP, RD28, TobRB7), (2) neurogenesis (Bib), (3) small-molecule-permeating channels (MIP, AQP3, NOD, Glpf), (4) unknown function (WCH-3, AtRB7, Pea R7A, FPS1). However, the biological functions are not well established. The most conserved residues in the first and the second halves of all MIP family proteins are asparagine-proline-alanine (NPA) sequences in the loops (NPA boxes). This structural similarity may lead to functional similarity (water and/or small molecule permeation). This signature sequence for the MIP family will facilitate the identification of new protein members of this family.
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PMID:[Water channel family proteins]. 753 36


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