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PubMed1997

Electrical impedance of the cochlear implant lubricants hyaluronic acid, oxycellulose, and glycerin.

Hyaluronic acid (Healon), oxycellulose (hydroxypropyl methylcellulose), and glycerin are lubricants used in cochlear implant surgery for atraumatic deep insertion of the electrode array into the scala tympani. The electrical impedances of these three lubricants were measured to assess possible effects on intraoperative evoked response measurements, such as the electrically evoked stapedius reflex and auditory brain stem response. The impedances of hyaluronic acid, oxycellulose, and saline were very similar and independent of frequency (20 Hz to 1 MHz). Glycerin had an excessively high impedance at low frequencies. A film of hyaluronic acid or oxycellulose around the electrode array immersed in saline did not have any measurable effect on the impedance; a film of glycerin resulted in a strongly reactive polarized layer. However, neither the far-field current spread nor the impedance between stimulated electrodes was affected by any of the lubricants applied as a thin film. This suggests that none of these lubricants affect intraoperative responses, when applied as a thin film.

Cochlear Implants↗
PubMed1987

Analysis of the glycerin test for Menière's disease.

The glycerin test has low sensitivity for Menière's disease using present published criteria. The purpose of this study is to compare the efficacy of standard empirical criteria with our theoretically based criteria. Subjects were 47 patients with Menière's disease and 45 patients with other causes of hearing loss and dizziness. Pure-tone thresholds and word-identification scores were determined before and 3 hours after administration of glycerin. The results were submitted to decision and multivariate discriminate analyses. The theoretically based criterion applied to pure-tone threshold testing alone was the most effective protocol for glycerin testing. Combining pure-tone thresholds and word-identification increased the false-positive rate without adequately increasing the true-positive rate, and provided no advantage over testing thresholds alone.

Audiometry, Pure-Tone↗
PubMed1981

Tentacle contraction in glycerinated Discophrya collini and the localization of HMM-binding filaments.

The contractile tentacles of the suctorian Discophrya collini contain a central microtubular axoneme as well as filamentous structures in the cortical epiplasm and in a fibrous collar around the axoneme at the tentacle base. The nature and possible roles of these components has been investigated by the use of reactivatable glycerinated cells. In these a mean tentacle contraction to 70% of the original length could be achieved by a 5-min treatment with a reaction mixture containing ATP, calcium and magnesium ions, the same treatment giving retraction to 30% in living cells. Both the microtubules of the axoneme and the filaments of the fibrous collar and epiplasm were present in the glycerinated cells, suggesting that these components consist of large water-insoluble molecules. The addition of heavy meromyosin to whole glycerinated cells resulted in the appearance of 36-50-nm spaced "tails" or filaments attached to the epiplasmic fibres and the aggregation of 3-6-nm filaments and electron-dense material in the region of the fibrous collar. Neither of these 2 features was apparent after treatment with ATP. It is suggested that actin-like filaments are localized in the region of the fibrous collar and in the epiplasm, and that these are involved in tentacle retraction; whilst the microtubules of the axoneme are concerned with feeding, and play only a cytoskeletal role in the contractile mechanism.

Animals↗
PubMed1975

Interaction of Ca, Mg and ATP in glycerinated taenia coli of guinea pig.

Ca sensitivity and energy dependence in the contractile proteins of the glycerinated taenia coli of guinea pig were studied. Above 1 X 10(-7)M Ca caused contraction in muscle which had been immersed in glycerol solution for 7 days in the presence of 5 mM Mg-ATP. Muscles which had been immersed in glycerol for 30 days had a higher Ca sensitivity than ones in glycerol for 7 days. When AMP or ADP (5, 10 MM) in place of ATP was added in the presence of 1 X 10(-6) M Ca and Mg(5, 10 mM), there was no contraction. Increasing the concentration of the same molar ratio of Mg-ATP from 1 to 20 mM in the presence of 1 X 10(-6) M Ca, the tension increased according to the Mg-ATP concentration. However, increase in Mg or ATP only in the presence of 1 X 10(-6) M Ca did not increase the tension. In conclusion, the three factors of Ca, Mg and ATP are essential for the activation of the contractile elements of glycerinated taenia. It is also suggested that the tension development in glycerinated taemia is controlled by the concentration of Ca and Mg-ATP complexes in intracellular fluid.

Adenosine Diphosphate↗
PubMed1990

Ca2(+)-insensitive contraction in glycerinated skeletal muscle fiber treated with additional troponin T.

An investigation was carried out on the effect of troponin T (TnT) protein on the Ca2(+)-sensitivity of fiber contraction when it was added to glycerinated muscle fiber. The TnT-treated fiber was observed to lose its Ca2(+)-sensitivity, so that it was seen to contract even in a Ca2(+)-free buffer solution. However, the treated fibers were not significantly different from the normally glycerinated ones in terms of tension magnitude. On the other hand, the fiber did not lose its Ca2(+)-sensitivity upon treatment in a similar manner with troponin I (TnI) or troponin C (TnC) protein instead of TnT; the tension magnitude was seen to decrease only with the TnI treatment. SDS-PAGE patterns of the TnT-treated fibers were different from those of glycerinated ones at the TnI and TnC band, which were fainter in the TnT-treated fibers than in the normal ones. DACM-labeled fibers also decreased in the DACM-labeled TnI and TnC proteins on gel as a result of the treatment with TnT protein. Further, those proteins were completely removed from fibers into extra medium. These findings suggest either that the additional TnT protein removes TnI and TnC subunits from the troponin (Tn) complex combined with thin filaments in the fibers, or that it exchanges the total Tn complex on the thin filaments.

Animals↗
PubMed1993

The influence of water, glycerin, paraffin oil and ethanol on skin mechanics.

Moisturizers and emollients do not only smooth the skin but also make it more supple. To clarify this effect, the short-term influence of tap water, paraffin oil, ethanol and glycerin on skin mechanics was studied. These substances are all common ingredients in moisturizers and emollients. Significant changes were seen already after 10 min of application. The distensibility and hysteresis (creep phenomenon) showed the most pronounced changes. Water and paraffin oil application caused significant (p < 0.03) increases after 10 min of application. The changes persisted for at least 10 min following paraffin oil application, while they disappeared sooner following water application. Application of ethanol had a negative effect on distensibility (p < 0.03). Glycerin appears to have a slow onset of action, but with the changes continuing even after application was stopped. The changes induced by glycerin appear to be similar to those induced by water and paraffin oil. The study shows that some of the most common ingredients in moisturizers and emollients are capable of inducing significant changes in the mechanical properties of human skin in vivo even after a 10-min application, suggesting that the outermost layers of the epidermis play an important role in skin mechanics.

Adult↗
PubMed1990

[THe mechanism of the hypotensive effect of glycerin].

In a group of healthy persons, changes in intraocular pressure, indices of hemodynamics of the eye (by the method of rheo-ophthalmography), changes in the heart's rate were studied before and after peroral usage of glycerine in a traditional dose. Authentic fall of intraocular pressure was recorded. Changes in blood filling of the eye proved to be unauthentic. Rheo-ophthalmographic investigations confirmed the leading role of the osmotic factor in the action of glycerine on the eye. It was firstly shown that the slowing down of the heart's rate after the usage of glycerine is likely to be of a neurotropic character. It is recommended to consider the mentioned facts in clinical practice.

Adolescent↗
PubMed1990

[The use of medicinal glycerin in treating alcoholics].

The possibilities are shown of using officinal glycerin as a polyatomic alcohol in the treatment of alcoholism, in particular, alcohol abstinent syndrome. The theoretical basis of using glycerin is the possibility of replacing ethanol by a substance with a similar chemical structure not possessing euphoric and narcotic effect. Clinical results showed the rationality of using glycerin as an antialcohol substance.

Administration, Oral↗
PubMed1987

[Production of glycerinated models of muscle fibers with phosphorylated myosin light chains].

A simple method for obtaining glycerinated muscle fibres of m. psoas of rabbit containing regulatory myosin light chains (LC2) of different levels of phosphorylation. The glycerination conditions stimulated endogenic kinase LC2 or phosphatase LC2. Glycerinated muscle fibres contained phosphorylated and dephosphorylated (levels of phosphorylation are 95 +/- 5%, and 5 +/- 5%, respectively) LC2 of myosin. To determine the level of phosphorylation the method of polyacrylamide gel electrophoresis in 8 M urea was modified.

Animals↗
PubMed1964

SOME OBSERVATIONS ON THE FINE STRUCTURE AND METABOLIC ACTIVITY OF NORMAL AND GLYCERINATED VENTRICULAR MUSCLE OF TOAD.

Fine structure, enzyme activity, and transmembrane potentials of normal and glycerinated ventricular muscle of the toad were studied. For electron microscopy, osmium tetroxide and Araldite were used. Plasma membranes are firmly attached to Z bands. Both the T system and sarcoplasmic reticulum are poorly developed. Small bodies of medium density may be lysosomes derived from the Golgi zone. Denser bodies may be catecholamine granules. Fine tubules of unknown significance, about 200 A in diameter and of considerable length, lie in conspicuous, although infrequent bundles. Glycogen and mitochondria are abundant. After weeks of extraction in 50 per cent buffered glycerol, most organelles were still present, and much of the gross damage was probably due to osmotic destruction of membranes weakened by extraction. Many mitochondria were well preserved. Plasma and nuclear membranes had diffuse outlines and tended to be broken. Considerable activity remained of the enzymes succinic dehydrogenase, cytochrome oxidase, and phosphorylase after the extraction, but decreased with prolonged soaking. The normal transmembrane potential was about 95 mv; in extracted muscle after 6 weeks it was about 35 mv. The view that glycerinated muscle is a simple system of actin and myosin is clearly wrong. The activity of other organelles still present must affect the actions of many drugs and ions experimentally added.

Animals↗
PubMed1978

Temporary loss of hearing after a glycerin test.

The glycerin test has been proposed as an adjunct in the diagnosis of Meniere's disease. Complications of the test are rare and usually minor. We describe a case in which a 20- to 40-dB hearing loss developed in the uninvolved ear of a patient during a standard glycerin test. He made a complete recovery within three days after the test. We discuss the possible mechanisms of the loss.

Auditory Threshold↗
PubMed2003

Pharmacokinetics of a new sustained-release formulation of theophylline sodium glycerinate in healthy subjects with a new asymmetric dosage regimen.

Pharmacokinetics of a new sustained-release formulation of theophylline sodium glycerinate in healthy subjects was studied. In this study, a new asymmetric dosage regimen was presented to achieve a better accordance with the chronotherapy of asthma. Each of 10 subjects was administered one tablet (equivalent to 0.1 g anhydrous theophylline) in the morning and four tablets in the evening for a consecutive 6 days and blood samples were collected at the predetermined time and analyzed by a validated HPLC method. This new regimen produced a steady and effective level of theophylline in plasma for the whole day, especially in the evening. A lower dose in the morning could reach the effective level (C(min)4.97 +/- 1.60 microg/mL and C(max)10.68 +/- 1.80 micro g/mL over the a.m. dosing interval) and a higher dose in the evening did not result in toxic levels but led to a reasonable concentration range (C(max)9.72 +/- 1.56 microg/mL over p.m. dosing interval), which could maintain a higher plasma theophylline concentration without the risk of serious adverse events and control asthmatic symptoms probably occurring during the night or early in the morning. The results suggested that the proposed asymmetric regimen was necessary, practicable and safe for twice daily sustained-release tablets of theophylline sodium glycerinate and also provides the basis for the clinical dosage regimen of other theophylline formulated products.

Adult↗
PubMed1983

High-performance liquid chromatographic assay for partially nitrated glycerins in nitroglycerin.

A high-performance liquid chromatographic method for determining the concentration of mononitroglycerins and dinitroglycerins in the commonly used pharmaceutical raw material nitroglycerin (10% w/w) on lactose USP is presented. A coefficient of variation of less than 5% for the partially nitrated glycerins was achieved over the range examined (0-4.0 micrograms/mg). Thirteen lots of raw material were examined and found to contain a total of less than 0.13% w/w partially nitrated glycerins. A variable wavelength detector (lambda = 218 nm) and a microphenyl column were employed. The mobile phase was acetonitrile-water (36:64) pumped at 2 ml/min. The internal standard was isosorbide dinitrate. Total analysis time was 12 min.

Chromatography, High Pressure Liquid↗
PubMed1984

Structural studies of glycerinated skeletal muscle. I. A-band length and cross-bridge period in ATP-contracted fibers.

An electron microscope study is reported of structural changes during ATP-induced contraction of glycerinated rabbit psoas. In the absence of ATP, A-band length is constant at sarcomere lengths above 1.9 micron, with average length of 1.54 mu. In ATP-treated fibers, A-band length is also constant at sarcomere lengths above 2.0 microns, but the apparent length of A-band decreases to approximately 1.3 micron, as sarcomere length decreases from 1.9 micron to 1.5 mu. The occurrence of short A-bands cannot be attributed to crumpling of thick filaments against Z-lines, since I-bands remain patent; nor to the presence of heterogeneous filaments, since resting muscle does not show comparable heterogeneity, nor to compressive artifacts, which are minor when knife edge is oriented parallel with fiber axis during microtomy . The decrease of A-band length appears related, at least in part, to disarray of terminal cross-bridges as the thick filaments encroach upon the N-line, a structure which becomes evident within the I-band during contraction of glycerinated fibers. In preliminary studies, optical transforms of A-bands from individual sarcomeres reveal a characteristic myosin layer-line pattern as low as 1.5 micron sarcomere length. A cross-bridge repeat of 143 A is obtained for sarcomeres above 1.6 micron length; however, an appreciable proportion of sarcomeres in the range from 1.5 micron to 1.9 mu length generate meridional reflections less than 143 A, and as low as 130 A.

Adenosine Triphosphate↗
PubMed1984

Effects of Ba2+ on the mechanical properties of glycerinated heart muscle.

At a muscle length, L0 (just taut), isometric tension and tension transients in response to rapid step stretches in length (mostly less than 1.2% of L0 within 2 ms) were measured at constant levels of Ba2+ activation of varying magnitude in glycerinated cat right-ventricular papillary muscles (2-3 mm long, 130-200 micron in diameter). The majority of the experiments were carried out at room temperature (26-27 degrees C) and at a pH of 6.8. The steady isometric tension increased as Ba2+ was varied from slightly below pBa 6 to about pBa 4. The concentration range of Ba2+-activated muscle was roughly 10 times higher than that of Ca2+-activated muscle. Maximum Ba2+-activated isometric tension was 79.0 +/- 4.2% (mean +/- SD, n = 8) of that activated with Ca2+. The tension transients in Ba2+-activated muscle were characterized by at least three distinct phases; an immediate tension increase coincident with the stretch, a rapid exponential tension decrease (time constant, tau 1 = 7.3 +/- 1.0 ms, n = 5) and a delayed exponential tension rise (tau 2 = 104 +/- 5.7 ms, n = 5). The profile of tension response was quite similar to that of Ca2+-activated muscle. These results suggest that in Ba2+-activated glycerinated heart muscle the cross-bridge turnover is taking place as in the Ca2+-activated muscle, but the number of active cross-bridges at maximally activated state is smaller than that of Ca2+-activated muscle.

Animals↗
PubMed1998

Role of patellar tendon on the population of muscle fiber types and the contractile properties of single glycerinated muscle fibers in quadriceps muscles of rats.

The role of the patellar tendon (PT) in the contractile properties of quadriceps muscle was investigated. After PT resection (partial or complete), PT reconstruction, or a sham operation, rats were forced to run on a rodent treadmill. The histochemical and mechanical characteristics of the vastus medialis (VM) and vastus lateralis (VL) muscles were examined 2, 4, and 8 weeks after treatment. There were no significant changes in either fiber type population or the contractile properties of glycerinated single muscle fibers from VM and VL 2 and 4 weeks after partial PT resection. Complete PT resection caused a decrease in the population of type I fibers in VM, while the running training after PT reconstruction increased the population of type I fibers in VM. For both the PT resection and PT reconstruction groups, the Hill coefficient, an indicator of the Ca2+ sensitivity of myofilaments, was calculated from the pCa-tension relationship of glycerinated single muscle fibers. In the PT reconstruction group, the Hill values for fibers isolated from VM were significantly decreased by running training, but the Hill values for VL were not. The effect of running training on the Ca2+ sensitivity of myofilaments in muscle fibers with PT reconstruction was different from that in muscle fibers without PT treatment. Both resection and partial resection of the PT in this animal model had heterogeneous effects on the contractile properties of quadriceps muscles; we presume that, clinically, we must give careful consideration to PT treatment.

Animals↗
PubMed1979

The structure of A segments from glycerinated skeletal muscle.

The A band of skeletal muscle consists of an array of thick myosin-containing filaments along with non-myosin proteins such as C protein and M line protein. In order to study the arrangement of the myosin and non-myosin components, A segments which are aggregations of thick filaments held together at the M line were prepared from glycerinated chicken pectoral and rabbit psoas muscles and examined by electron microscopy. Details of the preparative technique and comparison of the morphologies of A segments and I segments are provided. The A segments from chicken pectoral muscle exhibited 11 to 12 stripes in each half lateral to the bare zone. Several less distinct bands as well as subdivisions of the individual stripes were also observed. The periodicity of the major stripes in the A segments was 424 +/- 10 A. The A segments prepared from rabbit psoas muscle had a periodicity of 432 +/- 13 A, but in contrast with chicken A segments, fewer rabbit A segments showed this periodicity. We conclude that A segments can be separated from glycerinated chicken and rabbit skeletal muscles and compare our results with those of others who prepared A segments from frog and rabbit skeletal muscles in the absence of glycerol.

Animals↗
PubMed1986

Myokinase and contractile function of glycerinated muscle fibers.

Glycerinated rabbit psoas muscle fibers containing native CPK, ATPase, and myokinase activities were used and isometric contraction and relaxation responses to either ADP or ATP + CP or to ATP alone in the presence and absence of P1, P5-di(adenosine-5'-pentaphosphate), a myokinase inhibitor, were compared. In previous (14) work it was shown that CP generated more efficient and faster contraction and relaxation of glycerinated muscle fibers than ATP. The present work deals with the role of myokinase in the differential response of fibers to CP and ATP. Inhibition of the myokinase activity of these fibers caused slight diminution of the rate of contraction at physiological concentrations of ATP. Uninhibited fibers were not able to reach maximum contraction, because the tension began to drop gradually even in the presence of Ca2+. Addition of Ap5A permitted maximum contraction and the ability to stay at the contracted state. In the case of CP + adenosine nucleotides (ATP or ADP), myokinase activity decreased the rate of tension development which was statistically significant after 5-7 sec of contraction. Thus, a higher tension was obtainable when myokinase was inhibited. At high concentration of adenine nucleotides (greater than 2 mM) and in the absence of Ap5A, not only the maximum tension never was reached, but a spontaneous drop in tension was observed before addition of EGTA, as was seen with ATP alone. Relaxation was faster and more complete in the presence of uninhibited myokinase activity except that the ADP was low (125 mM). These observations provide further evidence for a close functional interaction of these three enzymes in the mechanism of contraction and relaxation, giving further support to the notion of the creatine-phosphocreatine energy shuttle.

Adenine Nucleotides↗