ABSTRACT
PURPOSE OF THE STUDY: The aim of arthroscopic Bankart repair is restoration of the anterior block mechanism and regaining stability. There are few studies that have tested the adequacy of the angle made with the glenoid and the height from the glenoid level of the repaired labral tissue, but the correlation with the clinical results is not clear. The aim of this study was to defi ne the correlation of the height and slope of the repaired labral tissue in the glenoid anterior with the clinical results. MATERIAL AND METHODS This prospective study included 20 patients who underwent an arthroscopic Bankart repair. To evaluate the labrum anatomy of the affected shoulder, 4 measurement parameters were defi ned as axial height (Ah), axial slope (As), oblique coronal height (Ch), and oblique coronal slope (Cs) on non-contrast T2 MRI. The measurements were taken preoperatively of the affected shoulder and at 1 year postoperatively of both the affected shoulder and the contralateral asymptomatic shoulder. The measured values were compared with each other and with the contralateral shoulder. Correlations of the anatomic values with the Constant-Murley scores recorded at 1, 3, 6, and 12 months postoperatively were examined with the Wilcoxon test. RESULTS The mean preoperative Constant score of the patients was 57.7 (32-77) and postoperative scores at 1, 3, 6, and 12 months were 63.6 (44-79), 77.8 (61-90), 89.6 (77-100), and 95.2 (79-100), respectively (p=0.001). There was a statistically signifi cant difference in the preoperative MRI measurements of the axial and oblique coronal plane labral height and slope values compared to the postoperative values and those of the asymptomatic contralateral shoulder (p< 0.05 for all). There was no statistically signifi cant difference between the labral height and slope values of both planes postoperatively compared to the asymptomatic contralateral shoulder (p= 0.776, p= 0.910, p= 0.132, p= 0.589, respectively). These increases in the radiological data were not found to be statistically signifi cant in the correlation analysis with the increases in the Constant-Murley scores (Ah p=0.935, As p=0.587, Ch p=0.078, Cs p=0.105). CONCLUSIONS This prospective study was conducted using conventional T2 magnetic resonance imaging, which was suffi cient for the measurement of labral height and slope. This study results showed no signifi cant correlation between the radiological and clinical outcomes. KEY WORDS: Bankart repair, labrum height, labrum slope, functional result.
Subject(s)
Arthroscopy , Shoulder , Humans , Prospective Studies , Scapula , Amputation, SurgicalABSTRACT
The effects of extremely low frequency electromagnetic fields of 75 Hz were studied on different membrane-associated enzymes. Only the activities of three enzymes out of seven exposed to the field decreased approximately of about 54-61% with field amplitudes above a threshold of 73-151 microT depending on the enzyme. The same field had no effect on the activities of either integral membrane enzymes such as Ca,ATPase, Na/K,ATPase, and succinic dehydrogenase or peripheral membrane enzymes such as photoreceptor PDE. The decrease in enzymatic activity of the field-sensitive enzymes was independent of the time of permanence in the field and was completely reversible. When these enzymes were solubilized with Triton, no effect of the field was obtained on the enzymatic activity, suggesting the crucial role of the membrane in determining the conditions for enzyme inactivation. The role of the particular linkage of the field-sensitive enzymes to the membranes is also discussed.
Subject(s)
Cell Membrane/chemistry , Cell Membrane/radiation effects , Electromagnetic Fields , Enzymes/chemistry , Enzymes/radiation effects , Membrane Proteins/chemistry , Membrane Proteins/radiation effects , Cells, Cultured , Dose-Response Relationship, Radiation , Enzyme Activation/radiation effects , Enzyme Stability/radiation effects , Erythrocyte Membrane/chemistry , Erythrocyte Membrane/radiation effects , Humans , Radiation Dosage , Synaptosomes/chemistry , Synaptosomes/radiation effectsABSTRACT
A high statistics measurement of the D(s)+ lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis of the two decay modes, D(s)+ --> phi(1020)pi+ and D(s)+ -->K*(892)0K+, used for the measurement. The measured lifetime is 507.4 +/- 5.5(stat) +/- 5.1(syst) fs using 8961 +/- 105 D(s)+ --> phi(1020)pi+ and 4680 +/- 90 D(s)+ --> K*(892)0K+ decays. This is a significant improvement over the present world average.
ABSTRACT
Extremely low frequency electromagnetic fields (ELF-EMFs) of 75 Hz with amplitudes above a threshold of about 125 microT have a dramatic effect on the adenylate kinase (AK) activity of the rod outer segment (ROS) membranes. In fact, the ATP production by ROS membranes or by purified disk membranes placed in the field decreased by approximately 54%. The decrease in enzymatic activity was independent of the time of exposure to the field and was completely reversible. When disk membranes were solubilized with Triton or a soluble isoform of AK was used, negligible effects of the field were obtained on the enzymatic activity, suggesting that the membrane has an important role in determining the conditions for the enzyme inactivation.
Subject(s)
Adenylate Kinase/radiation effects , Electromagnetic Fields , Rod Cell Outer Segment/radiation effects , Adenosine Triphosphate/radiation effects , Adenylate Kinase/antagonists & inhibitors , Animals , Cattle , Cell Membrane/enzymology , Cell Membrane/radiation effects , Isoenzymes/radiation effects , Polyethylene Glycols/pharmacology , Rod Cell Outer Segment/enzymology , Solubility , Surface-Active Agents/pharmacology , Time FactorsABSTRACT
Adenylate kinase activity in rod outer segment membranes of bovine retina decreased of about 55% when exposed to an extremely low frequency electromagnetic field of 75 Hz and 250 microT. The effect was independent of the time of permanence in the field. Negligible effects of the field were found on the enzymatic activity of a soluble isoform of adenylate kinase or of rod outer segment membranes solubilized with Triton, suggesting the importance of the membrane in determining the conditions of the enzyme inactivation.
Subject(s)
Adenosine Triphosphate/metabolism , Adenylate Kinase/metabolism , Adenylate Kinase/radiation effects , Cell Membrane/enzymology , Cell Membrane/radiation effects , Retinal Rod Photoreceptor Cells/enzymology , Retinal Rod Photoreceptor Cells/radiation effects , Adenylate Kinase/chemistry , Cells, Cultured , Dose-Response Relationship, Radiation , Electricity , Electromagnetic Fields , Enzyme Activation/radiation effects , Radiation DosageABSTRACT
A high statistics measurement of the Lambda(+)(c) lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis technique with particular attention to the determination of the systematic uncertainty. The measured value of 204.6 +/- 3.4 (stat) +/- 2.5 (syst) fs from 8034 +/- 122 Lambda(+)(c)-->pK(-)pi(+) decays represents a significant improvement over the present world average.
ABSTRACT
ATP is synthesized on the disk membrane isolated from rod outer segments of the bovine retina. Together with a slow component which accounted for a constant rate of about 22 nmol ATP/min/mg of protein and which was due to the adenylate kinase activity, a fast component with a maximal activity of about 58 nmol ATP/min/mg of protein was measured at physiological calcium concentrations. This fast activity disappeared in the presence of the Ca(2+) ionophore A23187, was inhibited by vanadate or thapsigargin but not by oligomycin, suggesting that this ATP synthesis is due to the reversal functioning of the Ca(2+)-ATPase previously found on the disk membranes.
Subject(s)
Adenosine Triphosphate/biosynthesis , Calcium-Transporting ATPases/metabolism , Rod Cell Outer Segment/enzymology , Adenosine Diphosphate/pharmacology , Animals , Calcimycin/pharmacology , Calcium/metabolism , Cattle , Enzyme Inhibitors/pharmacology , Ionophores/pharmacology , Rod Cell Outer Segment/drug effects , Thapsigargin/pharmacologyABSTRACT
A high-statistics sample of photoproduced charm from the FOCUS experiment has been used to search for direct CP violation in the decay rates for D+-->K(S)pi+ and D+-->K(S)K+. We have measured the following asymmetry parameters relative to D+-->K-pi+pi+: A(CP)(K(S)pi+) = (-1.6+/-1.5+/-0.9)%, A(CP)(K(S)K+) = (+6.9+/-6.0+/-1.5)%, and A(CP)(K(S)K+) = (+7.1+/-6.1+/-1.2)% relative to D+-->K(S)pi+. We have also measured the relative branching ratios and found Gamma(D+-->K(0)pi+)/Gamma(D+-->K-pi+pi+) = (30.60+/-0.46+/-0.32)%, Gamma(D+-->K(0)K+)/Gamma(D+-->K-pi+pi+) = (6.04+/-0.35+/-0.30)%, and Gamma(D+-->K(0)K+)/Gamma(D+-->K(0)pi+) = (19.96+/-1.19+/-0.96)%.
ABSTRACT
We have studied hadronic four-body decays of D(+) and D(+)(s) mesons with a K(S) in the final state using data recorded during the 1996-1997 fixed-target run of the Fermilab high energy photoproduction experiment FOCUS. We report a new branching ratio measurement of gamma(D(+)-->K(S)K-pi(+)pi(+))/gamma(D(+)-->K(S)pi(+)pi(+)pi(-)) = 0.0768+/-0.0041+/-0.0032. We make the first observation of three new decay modes with branching ratios gamma(D(+)-->K(S)K+pi(+)pi(-))/gamma(D(+)-->K(S)pi(+)pi(+)pi(-)) = 0.0562+/-0.0039+/-0.0040, gamma(D(+)-->K(S)K+K-pi(+))/gamma(D(+)-->K(S)pi(+)pi(+)pi(-)) = 0.0077+/-0.0015+/-0.0009, and gamma(D(+)(s)-->K(S)K+pi(+)pi(-))/gamma(D(+)(s)-->K(S)K-pi(+)pi(+)) = 0.586+/-0.052+/-0.043, where in each case the first error is statistical and the second error is systematic.
ABSTRACT
The present models of phototransduction for vertebrates and invertebrates have been reviewed and the relative literature updated. The emerging picture for vertebrate phototransduction is a result of a better knowledge of its general outlines, although some important details such as the role of calcium ions are still lacking. The molecular events involved in the rising phase of the electrical response have basically been understood, whilst those involved in response inactivation and recovery remain to be elucidated. In an overall strategy, the phototransduction in invertebrates shares a great deal of similarity with that in vertebrates but differs in the underlying molecular events. However, a complete picture of phototransduction in invertebrate photoreceptors has not yet emerged. The available data on the structure of the visual pigment rhodopsin reveal further details on the present model of the retinal-binding pocket of the protein and consequently of the "red shift" of the absorbance of retinal. The problem of the energy supplied during photoreception, in particular, the availability of ATP in the rod outer segment and the presence in the disk membranes of a Ca-ATPase are discussed. Finally, recent progress in understanding the molecular mechanisms of inherited retinal diseases and relative gene identification are summarized.
Subject(s)
Rhodopsin/physiology , Vision, Ocular/physiology , Animals , Humans , Photoreceptor Cells, Invertebrate/physiology , Photoreceptor Cells, Vertebrate/physiology , Retinal Diseases/metabolismABSTRACT
Using a large sample of photoproduced charm mesons from the FOCUS experiment at Fermilab (FNAL-E831), we observe the decay D0-->K+pi- with a signal yield of 149+/-31 events compared to a similarly cut sample consisting of 36 760+/-195 D0-->K-pi+ events. We use the observed ratio of D0-->K+pi- to D0-->K-pi+ (0.404+/-0.085+/-0.025)% to obtain a relationship between the D0 mixing and doubly Cabibbo suppressed decay parameters.
ABSTRACT
The rod outer segments of bovine retina contain two different adenylate kinases: a soluble activity, which is not sensitive to calcium ion, and an activity bound to disk membranes, which is dependent on the calcium levels. In fact, the maximal activity associated to the disks is reached at Ca(2+) concentrations between 10(-6) and 10(-7) M, which is the range of calcium level actually present in the rod cell. The Michaelis-Menten kinetics of the enzyme activity on disk membranes was determined and the actual concentrations of ATP, AMP and ADP were measured in the photoreceptor outer segment. Therefore, the physiological relevance of the adenylate kinase activity was discussed considering the above results. The formation of ATP catalyzed by the enzyme seems appropriate to supply at least some of the reactions necessary for phototransduction, indicating that ATP could be regenerated from ADP directly on the disk membranes where the photoreception events take place.
Subject(s)
Adenylyl Cyclases/metabolism , Retina/enzymology , Rod Cell Outer Segment/enzymology , Adenosine Diphosphate/metabolism , Adenosine Triphosphate/metabolism , Animals , Calcium/metabolism , Calcium/pharmacology , Cattle , In Vitro Techniques , Light , Optic Disk/enzymologyABSTRACT
Purified disk membranes from rod outer segments of the bovine retina were able to synthesize ATP with a maximal activity (about 52 nmoles ATP/min/mg of protein) at physiological calcium concentrations. This activity was inhibited by vanadate or thapsigargin but not by oligomycin, suggesting the reversal functioning of the disk Ca(2+)-ATPase, which would act as a ATP synthesizer at the expense of the calcium gradient between the disks and the cytoplasm of the rod outer segment. The results are discussed in terms of the need of an immediate source of ATP on the disk membranes where the energy is required to supply the rapid reactions of the photoreception processes.
Subject(s)
Adenosine Triphosphate/biosynthesis , Calcium-Transporting ATPases/metabolism , Calcium/metabolism , Rod Cell Outer Segment/metabolism , Adenosine Diphosphate/metabolism , Animals , Cattle , Phosphates/metabolism , Photoreceptor Cells/metabolismABSTRACT
Recent studies on rhodopsin structure and function are reviewed and the properties of vertebrate as well as invertebrate rhodopsin described. Open issues such as the 'red shift' of the absorbance spectra are emphasized in the light of the present model of the retinal-binding pocket. The processes that restore the rhodopsin content in photoreceptors are also presented with a comparison between vertebrate and invertebrate visual systems. The central role of rhodopsin in the phototransduction cascade becomes evident by examining the main reports on light-activated conformational changes of rhodopsin and its interaction with transducin. Shut-off mechanisms are considered by reporting the studies on the sites of rhodopsin phosphorylation and arrestin binding. Furthermore, recent findings on the energetics of phototransduction point out that the ATP needed for photoreception in vertebrates is synthesized in the outer segments where phototransduction events take place.
Subject(s)
Rhodopsin/physiology , Vision, Ocular/physiology , Amino Acid Sequence , Animals , Energy Transfer , Humans , Invertebrates , Molecular Sequence Data , Protein Structure, Secondary , Retinal Diseases , Rhodopsin/chemistry , VertebratesABSTRACT
Preliminary measurements in a proportional counter with two independently counting wires showed that counting rates up to 10(6) counts s(-1) wire(-1) can be reached without critical loss in the 'true versus measured' linearity relation. Results obtained with a detector containing 30 active wires (2 mm pitch) are presented. With each wire is associated a fast pre-amplifier and a discriminator channel. Global counting rates in excess of 10(7) events s(-1) are reported. Dead-time losses are corrected by use of simple mathematical-modelling functions. Data-acquisition systems are described for one-dimensional (real-time) and two-dimensional (off-line) position-sensitive detection systems.
ABSTRACT
The striking properties of monolayers and multilayers of photosensitive proteins obtained by using the Langmuir-Blodgett technique are described. The close packing of the protein molecules, which preserve most of the properties found in solution, seems to be the main cause for their thermal stability, which in some cases reached a temperature of 200 degrees C without the loss of the protein secondary structure. The review is focused on three of the most intensively studied photosensitive proteins, namely photosynthetic reaction centres, bacteriorhodopsin and bovine rhodopsin, and on their possible applications as molecular optical devices.
Subject(s)
Bacteriorhodopsins , Photobiology , Photosynthetic Reaction Center Complex Proteins , Rhodopsin , Energy Transfer , Photobiology/trendsABSTRACT
Two-dimensional close packing of purified bovine rhodopsin, made by the Langmuir-Blodgett technique, was characterized by small angle x-ray scattering and nanogravimetric measurements. The area occupied by a molecule of rhodopsin in the film was approximately 1100 Angstrum2 and the periodicity of the layers resulted in 59 Angstrum. The circular dichroism measurements showed that bleached rhodopsin in Langmuir-Blodgett film had high thermal stability, in fact, reaching a temperature of 150 degrees C without a loss of the secondary structure. Moreover, when the film was made up in the dark, rhodopsin maintained its stability up to at least 200 degrees C and its characteristic absorbance peak at 500 nm up to about 90 degrees C.
Subject(s)
Protein Conformation , Rhodopsin/chemistry , Animals , Cattle , Circular Dichroism , Drug Stability , Hot Temperature , Rhodopsin/isolation & purification , Rod Cell Outer Segment , Thermodynamics , X-Ray Diffraction/methodsABSTRACT
Active Ca2+ transport was measured in microsomal vesicles prepared from bovine retinae and was compared with that in disk membranes of the photoreceptor cells of the same retina. The 45Ca uptake was dependent on the presence of Mg(2+)-ATP and was inhibited by vanadate or when GTP substituted for ATP. The dependence of calcium uptake on the external free Ca2+ concentration gave a KM = 13 microM or a KM = 0.1 microM for disks and microsomal vesicles, respectively. A phosphorylated intermediate (E-P) of Ca(2+)-ATPase of about 100 kDa was isolated in microsomal vesicles. The E-P formation was strongly inhibited by thapsigargin and partially by 2,5-di-(-butyl)benzohydroquinone. Digestion of disks or microsomes with calpain had no effect on the phosphorylated intermediate, while digestion with trypsin produced two fragments of approximately 55 kDa and 35 kDa. These results suggest that bovine retinal microsomes contain a calcium pump belonging to the SERCA family.
Subject(s)
Calcium-Transporting ATPases/analysis , Endoplasmic Reticulum/enzymology , Microsomes/enzymology , Retina/enzymology , Animals , Cattle , Cell Membrane/physiology , Humans , Molecular Weight , Phosphorylation , Retina/ultrastructure , Rod Cell Outer Segment/metabolism , Rod Cell Outer Segment/ultrastructure , Sarcoplasmic Reticulum/enzymologyABSTRACT
The Ca(2+)-pump isolated in rod outer segment disk membranes as aspartylphosphate intermediate E-P has been characterized: the 100 kDa phosphoprotein was completely inhibited by thapsigargin, was not sensitive to digestion by calpain, and displayed a tryptic digestion pattern with the formation of two autophosphorylatable fragments of about 55 and 35 kDa. These results are typical of the calcium pumps of sarcoplasmic or endoplasmic reticulum calcium and differ from those of plasma membrane, such as the Ca(2+)-ATPase of the red blood cells, here shown as controls. The physiological role of calcium pump in disk membranes of vertebrate photoreceptors is discussed in terms of intracellular calcium buffering.
Subject(s)
Calcium-Transporting ATPases/metabolism , Rod Cell Outer Segment/enzymology , Animals , Calcium-Transporting ATPases/antagonists & inhibitors , Cattle , Cell Membrane/drug effects , Cell Membrane/metabolism , Hydrolysis , Terpenes/pharmacology , Thapsigargin , Trypsin/metabolismABSTRACT
The existence of a Ca2+ pump in rod outer segment disks of bovine retina is strongly suggested by the isolation on sodium dodecyl sulfate polyacrylamide gel electrophoresis of a hydroxylamine-sensitive phosphorylated intermediate (E-P) of molecular mass of about 100 kDa as well as by measurements of active calcium transport and adenosine 5'-triphosphate (ATP) hydrolysis. Active Ca2+ uptake by disks was dependent on the presence of Mg(2+)-ATP, was inhibited by vanadate or lanthanum and appeared poorly sensitive to calmodulin. ATP hydrolysis by disk membranes was a function of free Ca2+ concentration in the absence of exogenous Mg2+. The presence of a Ca2+ pump on disk membranes is discussed in terms of its possible role in Ca2+ ion buffering during photoreceptor cell functioning.