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At least 199 records · Page 11Linked to original sources

PubMed1998

Chronic exertional compartment syndrome: MR imaging at 0.1 T compared with tissue pressure measurement.

PURPOSE: To compare low-field-strength magnetic resonance (MR) imaging with intracompartmental tissue pressure measurement for the diagnosis of chronic exertional compartment syndrome. MATERIALS AND METHODS: Thirteen patients suspected clinically of having chronic exertional compartment syndrome in the anterior tibial compartment were studied. MR imaging at 0.1-T and intracompartmental tissue pressure measurements of the anterior tibial compartment were performed before and immediately after standard treadmill exercise. The MR measurements were also obtained in eight anterior tibial compartments of four control subjects without the syndrome. Intracompartmental signal intensity was normalized with the signal intensity from lower leg tissues not affected by the compartment syndrome (subcutaneous fat, tibial bone marrow, or superficial posterior compartment). RESULTS: In the patient group, the relative change from rest to the postexercise state in the normalized MR signal intensity parameter correlated significantly (P < .001) with the respective change in intracompartmental pressure and with the absolute postexercise pressure. In the patients with elevated postexercise intracompartmental pressure, the increase in normalized MR signal intensity from rest to the postexercise state was significantly greater (P < .01) than that in the control subjects or the patients with normal or borderline postexercise intracompartmental pressure. In the latter two groups, the MR results were comparable. CONCLUSION: MR imaging performed at rest and immediately after muscular exercise is a promising method for diagnosing chronic exertional compartment syndrome and assessing its severity.

Adult↗

PubMed1997

Intramuscular deoxygenation during exercise in patients who have chronic anterior compartment syndrome of the leg.

Currently, the definitive diagnosis of chronic compartment syndrome is based on invasive measurements of intracompartmental pressure. We measured the intramuscular pressure and the relative oxygenation in the anterior compartment of the leg in eighteen patients who were suspected of having chronic compartment syndrome as well as in ten control subjects before, during, and after exercise. Chronic compartment syndrome was considered to be present if the intramuscular pressure was at least fifteen millimeters of mercury (2.00 kilopascals) before exercise, at least thirty millimeters of mercury (4.00 kilopascals) one minute after exercise, or at least twenty millimeters of mercury (2.67 kilopascals) five minutes after exercise. Changes in relative oxygenation were measured with use of the non-invasive method of near-infrared spectroscopy. In all patients and subjects, there was rapid relative deoxygenation after the initiation of exercise, the level of oxygenation remained relatively stable during continued exercise, and there was reoxygenation to a level that exceeded the pre-exercise resting level after the cessation of exercise. During exercise, maximum relative deoxygenation in the patients who had chronic compartment syndrome (mean relative deoxygenation [and standard error], -290 +/- 39 millivolts) was significantly greater than that in the patients who did not have chronic compartment syndrome (-190 +/- 10 millivolts) and that in the control subjects (-179 +/- 14 millivolts) (p < 0.05 for both comparisons). In addition, the interval between the cessation of exercise and the recovery of the pre-exercise resting level of oxygenation was significantly longer for the patients who had chronic compartment syndrome (184 +/- 54 seconds) than for the patients who did not have chronic compartment syndrome (39 +/- 19 seconds) and the control subjects (33 +/- 10 seconds) (p < 0.05 for both comparisons).

Case-Control Studies↗

PubMed2002

[Risk of compartment syndrome in open and closed tibial fractures].

BACKGROUND: In orthopaedic traumatology; acute compartment syndrome is a common complication associated with tibial fractures. In our study, we investigate differences, if any, between open and closed tibialfractures in terms oftheir risk of compartment syndrome. METHODS: Fourty-two tibial fractures of 39 patients, 29 (69%) closed and 13 (31%) open, having the risk of acute compartment syndrome according to the clinical examination, were monitored following traumas during which their DP (DP= Diastolic blood pressure -Absolute compartment pressure) and absolute compartment pressures were measured via intracompartmental pressure measuring equipment. RESULTS: Average absolute compartment pressure was found to be 31.25 mmHg in open and 29,32 mmHg in closed fractures (p=O,484) whereas average DP was measured to be 47,46 mmHg in open and 49,66 mmHg in closedfractures (p=O,415). According to student's test, the difference between the two groups was not significant. We found the incidence of acute compartment syndrome as 7, 7% in open fractures, 6.9% in closed and 7, 1 % in overall tibial fractures andfasciotomy was carried out in those cases. CONCLUTION: Statistically not significant difference between the pressure levels,found in open and closed tibialfractures, showed that open type oftibialfractures holds the risk of compartment syndrome as much as the closed one.

Compartment Syndromes↗

PubMed2004

[Acute compartment syndrome of the foot].

In two patients, a girl aged 2 and a man aged 52 years, who had suffered a severe crush trauma, acute compartment syndrome of the foot was diagnosed. Decompression by means of one medial and two dorsal dermato-fasciotomy incisions was carried out and fractures of the metatarsals were repaired using K-wires. The girl recovered completely, but the man developed progressive necrosis in the flexors of the foot and on the skin on the foot sole which necessitated amputation of the foot. Acute compartment syndrome of the foot is an uncommon disease and is mainly characterised by extreme pain and often diffuse swelling of the foot. It is a serious threat to the foot which can lead to severe long-term complications including contractures, deformity and paralysis. Compartment syndrome of the foot is a primary clinical diagnosis. When in doubt, direct pressure measurement of the foot compartments should be done by means of needle catheterisation. If compartment pressure exceeds 30 mm Hg, acute dermato-fasciotomy of all nine compartments is indicated. A combined medial and dorsal approach is adopted to release the foot compartments; three incisions are usually sufficient. If fractures are present, these are repaired at the same time. Within four hours an unnoticed compartment syndrome can lead to irreversible ischaemia of the nerves and muscle tissue with long-term irreversible consequences.

Acute Disease↗

PubMed1986

A comparative study of the tolerance of skeletal muscle to ischemia. Tourniquet application compared with acute compartment syndrome.

In this study, the tolerance of skeletal muscle to tourniquet application (ischemia) and to acute compartment syndrome (ischemia and pressure) was compared. In five animals, the cuff of a pneumatic tourniquet was inflated to 350 millimeters of mercury at the level of the thigh for three hours. In five other animals, an acute experimental compartment syndrome was created in one anterolateral compartment by autologous plasma infusion. The compartment pressure (measured by wick catheter) was maintained at a level equal to the mean arterial pressure for three hours. At three hours, reperfusion was established in both groups, either by tourniquet release or by decompressive fasciotomy and epimysiotomy. During both the ischemic period and a two-hour recovery period immediately thereafter, the mean intracellular pH and high-energy phosphate profile (levels of adenosine triphosphate and phosphocreatine) of the muscles of the anterolateral compartment were monitored non-invasively by phosphorus nuclear magnetic-resonance spectroscopy. Muscle biopsies were done the following day to take specimens for electron microscopic analysis of ultrastructural cellular degeneration. During ischemia, the cellular levels of phosphocreatine decreased at an identical rate in both groups. In contrast, the levels of adenosine triphosphate diminished rapidly in the animals with the compartment syndrome, but remained unchanged in the tourniquet group. Ischemic muscle acidosis was more severe in dogs with the compartment syndrome. In the tourniquet group, the phosphocreatine, adenosine triphosphate, and pH were all normal within fifteen minutes after release of the tourniquet, but these values remained depressed even two hours after fasciotomy in the group with compartment syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗

PubMed1998

[Compartment simulation models and physiologic use in pharmaco- and toxicokinetics].

The pharmaco- and toxicokinetic studies describe the process of absorption, distribution, metabolism and elimination of drugs or chemical compounds in animals and humans. In simple compartmental models, the body is divided into basic compartments, central and peripheral. The central compartment is an equilibrium of arterial and venous blood flows, and the peripheral one is connected to the central compartment through a series of flow rate constants that describe the flow of chemicals in both directions. For instance, we can use the PH/EDSIM software for calculating the constants. The flow of the material from one to the other reflected by vectorial connections of two types of kinetics: linear and Michaelis-Menten (nonlinear). At present, the PB-PK models (physiologically-based pharmacokinetic models), which rely on actual physiological (breath rates, blood flow rates and tissue volumes), biochemical and metabolic parameters, tend to be more commonly used. Tissue groups or compartments that are frequently applied in PB-TK model include organs, muscle, fat tissue and the liver. Tissue compartments are connected by arterial and venous blood flows, and each compartment is characterised by a unique set of differential equations. The flow rate constants that describe that flow of materials from and to the compartments, and the rate of change in the amount of chemical in each compartments are directly proportional to the blood flow rate, tissue solubility and organ value.

Animals↗

PubMed1998

Inferior dislocation of the glenohumeral joint combined with the compartment syndrome of the upper arm: case report.

Compartment syndromes occurring in the forearm and leg are not infrequent. However, reports of compartment syndrome of the upper arm are conspicuously rare. Inferior dislocation of the shoulder combined with compartment syndrome has rarely been reported in the literature. We report our experience with a patient with inferior dislocation of the glenohumeral joint combined with compartment syndrome of the upper arm. A 29-year-old man had traumatic inferior dislocation of the glenohumeral joint combined with severe swelling of the shoulder and upper arm. After close reduction, the shoulder and upper arm were still tensely swollen. Compartment pressure of the upper arm was measured using a digital manometer (Quick Pressure Monitor 295-1, Stryker) and remained very high, thus, fasciotomy was performed. After debridement and skin graft, the arm healed without sequelae. When a patient has a fracture dislocation of the shoulder joint associated with a swollen arm, compartment syndrome of the upper arm should be included as a differential diagnosis. Detecting the compartment pressure can confirm the diagnosis of compartment syndrome objectively.

Adult↗

PubMed1998

Neuromuscular specializations of the pharyngeal dilator muscles: I. Compartments of the canine geniohyoid muscle.

BACKGROUND: Little is known about the structure and innervation of the geniohyoid muscle (GH), which is an important pharyngeal dilator muscle activated in swallowing and respiration. METHODS: The neuromuscular specializations of the canine GH were studied in detail by using a combination of histological, histochemical, and anatomical techniques. First, hematoxylin and eosin staining, Gomori's rapid one-step trichrome stain, and silver impregnation were used to determine the terminations of muscle fibers and existence of fibrous septa within the muscle (n = 8). Second, myofibrillar ATPase staining was employed to document the muscle fiber type distribution (n = 8). Finally, Sihler's stain (n = 10) and wholemount acetylcholinesterase staining (n = 8) were used to examine the distribution of the nerve supply within the muscle. RESULTS: The canine GH is divided into rostral and caudal compartments, which are arranged in series and separated by a transverse fibrous septum. Each compartment receives its own primary nerve branch, which supplies a separate motor endplate zone. The rostral compartment is innervated bilaterally, whereas the caudal compartment is innervated ipsilaterally. The rostral compartment was composed of significantly more type I (slow twitch) muscle fibers (56%) than the caudal compartment (25%). CONCLUSIONS: The canine GH is composed of two in-series neuromuscular compartments rather than a single muscle as traditionally believed. This anatomical finding suggests that these two compartments may function independently under different physiological conditions.

Acetylcholinesterase↗

PubMed1982

A histochemical analysis of identified compartments of cat lateral gastrocnemius muscle.

The lateral gastrocnemius muscle of cats can be divided into four discrete subvolumes or compartments which are supplied by the primary branches of its muscle nerve. The histochemical profile of each compartment was determined from the reaction for myosin ATPase after acid preincubation. Fibers were classified as fast-twitch glycolytic (FG), fast-twitch oxidative-glycolytic (FOG), or slow-twitch oxidative (SO). Each compartment in each cat examined was found to contain a relatively uniform distribution of different types of fibers. The most proximal LG compartment contains mainly type FG fibers, with relatively few type SO fibers; the most distal compartment, while still predominated by type FG fibers, contains a significantly larger proportion of type SO fibers. The histochemical profile of the intermediate compartments indicates that they contain fibers which lie intermediate in composition between these two. These results are consistent with the notion that LG compartments consist of aggregations of motor units, arranged such that muscle fibers comprising a single motor unit are contained within a single compartment.

Animals↗

PubMed2001

Pretarsal fat compartment in the lower eyelid.

It is generally accepted that there are three infraorbital fat regions in the lower eyelid; medial, central, and lateral compartments. However, removing only the fat in the lateral compartment does not remove the bulge just below the eyelashes, which is caused by another fat pad. The aim of this study was to describe the anatomy of the pretarsal fat compartment and to demonstrate its clinical implications in lower lid blepharoplasty. Ten cadavers (total 20 lower eyelids) were studied. A skin-muscle flap was reflected to expose the soft pretarsal structures. A small stab incision was made on the lateral portion of the sac containing fat on the tarsus. Methylene blue dye was injected into the sac. Specimens were fixed and sagittal sections in four different planes were prepared for histological analysis. The injected dye remained within the sac and demarcated it as a pear or cone shaped structure. This encapsulated fat compartment sits on the lateral half of the tarsal plate above the lateral compartment fat. Auxillary or submuscular fat is well known. This study, however, designates the pretarsal fat as "encapsulated" in a compartment instead of being unbound. We have named it the "pretarsal fat compartment." Histologically, orbital septal fibers separate "pretarsal fat" from lateral infraorbital fat. It is recommended that fat in the pretarsal fat compartment be removed during lower lid blepharoplasty in order to alleviate the bulge or knoll of the skin just below the lower eyelashes.

Adipose Tissue↗

PubMed1976

Critical analysis of "flip-flop" phenomenon in two-compartment pharmacokinetic model.

Computer simulations were used to examine the effect of first-order absorption on the disposition of one- and two-compartment model drugs. Two-compartment systems that attain a clinically acceptable beta-phase after rapid intravenous injection were perturbed by introduction of drug via first-order absorption. The validity of perceiving such a system as a potential "flip-flop" model was tested by comparing the negative slopes of log-linear plasma-time profiles to known values for ka and beta for various values of ka, k12, k21, and k10. Although most log-linear plots showed excellent correlation coefficients (r2 greater than 0.996), their negative slopes (S) did not represent either ka or beta under various combinations. A similar consideration of the one-compartment model enabled a comparison to be made between the two systems. Maximum negative errors were observed for both one- and two-compartment drugs as ka leads to k2 or beta, respectively. The value for S provided a good estimate of the absorption rate constant, ka, when k2 greater than or equal 2ka (one compartment) or beta greater than or equal 2ka. The elimination rate constant (k2 or beta) could be obtained from S for all one-compartment and some two-compartment drugs when the value of ka was approximately twice that of k2 or beta. Large positive errors also were observed with certain two-compartment drugs where the ratio of the four rate constants apparently linearized a nonlinear plasma profile. Conditions wherein S may be expected to approach beta wherein S approaches ka are clearly defined.

Absorption↗

PubMed1994

A re-evaluation of the properties of the three-compartment model of intestinal weak-electrolyte absorption.

The three-compartment model for intestinal weak-electrolyte transport provides an equation which predicts the flux ratio (the ratio of the forward and reverse fluxes of weak electrolyte across the intestine) from the dissociation constant, given that coefficients in the equation are specified. Using the equation to evaluate the coefficients from flux ratio and dissociation constant data fails to provide a unique set of values for the coefficients, although it does provide four dissimilar but related sets of values. Differentiation to determine the position and size of the maximum flux ratio provides a relationship between the model coefficients which shows why it is that four sets of coefficients can be used in the equation when it is applied to experimental data. Coefficient sets are derived for all available flux ratio data in the literature. These always contain a variant which requires the intermediate compartment to be more acid than the end compartment. Further specification of the flux ratio equation either by combining data from different physiological circumstances or by adding voltage terms, reduces the four possible coefficient sets to a single set, again requiring the intermediate compartment to be more acid than the end compartment. Estimates of the intermediate-compartment pH agree well with electrode estimates of mucosal surface pH. The present re-evaluation of the three-compartment model resolves an apparent contradiction between experimental and previous theoretical results which indicated a more alkaline intermediate compartment. Instead of contradicting experimental findings, results from the modelling process confirm that the "acid microclimate" version of the model is the better representation of the system that causes asymmetry in weak electrolyte flows across the small intestine.

Electrolytes↗

PubMed1994

Development of a pharmacokinetic model for chromium in the rat following subchronic exposure. I. The importance of incorporating long-term storage compartment.

A pharmacokinetic model of chromium depuration in the rat has been developed under subchronic exposure conditions. Rats were exposed to 100 ppm Cr(VI) in their drinking water for 6 weeks, followed by a 140-day period of depuration. Tissue concentrations of Cr at the end of the 6-week exposure period were greatest in the bone, spleen, and kidney, with lower concentrations present in the liver and blood. The overall kinetics of Cr depuration from the tissues were relatively slow, especially for the largest compartment which included bone. The results indicated that the half-life of Cr in bone exceeded 100 days. A three-compartment model was developed to fit the data. Liver, kidney, and spleen were grouped into a single compartment which was linked to a major storage compartment (i.e., bone, skin, hair, and muscle) via the blood. Using this model, the time to a 50% reduction of whole body Cr (i.e., loss of total Cr mass for the whole rat) was calculated to be about 80 days. The higher half-life for the storage compartment of 100 days is due to the relative weights of the compartments and the more rapid loss of Cr from the liver, kidney, and spleen compartment. The data suggest that Cr may be sequestered and release of Cr by the storage compartment over an extended period of time, thereby, may play an important role in maintaining elevated body burdens and tissue concentrations of Cr following long-term exposure to this toxic metal.

Animals↗

PubMed2006

Assessing nonlinearity in compartment models via the relative curvature measure.

In pharmacokinetics, compartment models often play an important role in the description of the concentration of the drug in the blood over time after its administration to an individual. Statistical inference in these models can be conducted based on a linear approximation with respect to the parameter related to pharmacokinetic indices, in the same way that the usual nonlinear regression models are dealt with. Therefore, it is necessary to assess the degree of nonlinearity in a compartment model and to evaluate its effect on the linear approximation. The relative curvature measure that enables us to assess the intrinsic and parameter-effects (PE) nonlinearity can be used, but in practice it has not been applied to compartment models in pharmacokinetics. One reason may be that the relative curvature measure cannot be directly applied to blood drug concentration data that exhibit heteroscedasticity. Therefore, the relative curvature measure including the heteroscedastic variance function was utilized to assess the nonlinearity in the compartment models, and in particular, the influences of some of the reparameterizations that are empirically used in fitting the compartment models were examined. Several examples showed that the reparameterized compartment model had less PE nonlinearity than the original compartment model, but that several reparameterizations could increase the PE nonlinearity. In addition, by means of a simulation experiment with heteroscedastic blood drug concentration data, the accuracy, and precision of the relative curvature measure with the heteroscedastic variance function were evaluated and compared with those of the original relative curvature measure. The results showed that the relative curvature measure with the variance function was not affected by heteroscedastic blood drug concentration data and could be utilized for the assessment of the nonlinearity in compartment models.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2004

Analysis of post-lysosomal compartments.

Lysosomes are acidic intracellular compartments and are regarded as degradative and the end point, of the endocytic pathway. Here we provide evidence for the generation of acid hydrolase poor and non-acidic post-lysosomal compartments in NRK cells that have accumulated non-digestible macromolecules, Texas red-dextran (TR-Dex), within lysosomes. When TR-Dex was fed to the cells for 6h, most of the internalized TR-Dex colocalized with a lysosomal enzyme, cathepsin D. With an increase in the chase period, however, the internalized TR-Dex gradually accumulated in cathepsin D-negative vesicles. These vesicles were positive for a lysosomal membrane protein, LGP85, and their formation was inhibited by treatment of the cells with U18666A, which impairs membrane transport out of late endosomal/lysosomal compartments, thereby suggesting that the vesicles are derived from lysosomes. Interestingly, these compartments are non-acidic as judged for the DAMP staining. The results, therefore, suggest that the excess accumulation of non-digestible macromolecules within lysosomes induces the formation of acid hydrolase poor and non-acidic post-lysosomal compartments. The fact that treatment of the cells with lysosomotropic amines or a microtubule-depolymerization agent resulted in extensive colocalization of TR-Dex with cathepsin D further indicates that the formation of the post-lysosomal compartments depends on the lysosomal acidification and microtubule organization. Furthermore, these results suggest bi-directional membrane transport between lysosomes and the post-lysosomal compartments, which implies that the latter are not resting compartments.

Androstenes↗

PubMed2006

Anatomic variations of the infraorbital fat compartment.

Resection of the infraorbital fat is performed in blepharoplasty of the lower eyelid, however, the previous anatomical reports on its compartmentalization have been in disagreement. The aim of this study was to classify the infraorbital fat based on the extent of compartmentalization, and to clarify its topographic relationship with the surrounding structures. Sixty orbits from 30 cadavers were dissected. The infraorbital fat was classified into four types based on its compartmentalization. In type I, which was the most common type (60.0%), the infraorbital fat was compartmentalised into three encapsulated medial, central, and lateral parts, which were side by side. In type II (11.7%), the medial or lateral compartment, or both compartments were under the central fat compartment. In type III (26.7%), there were two compartments, the medial and remaining part or the lateral and remaining part. In type IV (1.7%), the fat was not compartmentalised, but presented as a single pad. The average heights from the inferior orbital rim, the average widths, and the average distances from the fornix were 7.3, 17.2, and 7.1 mm in the medial compartment, 8.9, 24.2, and 8.0mm in the central compartment, and 8.1, 17.2, and 6.9 mm in the lateral compartment, respectively. The average distance from the end of the margin of the stretched lower eyelid to the most cephalic point in the compartments was 8.6 mm. These results are relevant to blepharoplasty with removal of the infraorbital fat.

Adipose Tissue↗

PubMed1996

Plant cells contain two functionally distinct vacuolar compartments.

The plant cell vacuole has multiple functions, including storage of proteins and maintenance of an acidic pH where proteases will have maximal activity. It has been assumed that these diverse functions occur in the same compartment. Here, we demonstrate that antibodies to two different tonoplast intrinsic proteins, alpha-TIP and TIP-Ma27, label vacuole membranes of two different compartments within the same cell. These compartments are functionally distinct, because barley lectin, a protein stored in root tips, is exclusively contained within the alpha-TIP compartment, while aleurain, a protease that serves as a marker for an acidified vacuolar environment, is exclusively contained within the TIP-Ma27 compartment. As cells develop large vacuoles, the two compartments merge; this may represent a process by which storage products in the alpha-TIP compartment are exposed to the acidic lytic TIP-Ma27 compartment for degradation.

Cell Compartmentation↗

PubMed1999

Estimation of intradermal disposition kinetics of drugs: I. Analysis by compartment model with contralateral tissues.

PURPOSE: The objectives of dermal application of drugs are not only systemic therapeutic, but also local ones. We would expect its intradermal kinetics to be dependent on its therapeutic purpose. To develop more efficient drugs for local or systemic therapeutics, it will be important to estimate quantitatively the intradermal disposition of drugs applied topically. We tried, therefore, to develop the compartment model to describe the intradermal disposition kinetics after topical application of drugs. METHODS: In vivo percutaneous absorption study for antipyrine, a model compound, was performed using rats with tape-stripped skin, using the assumption that the stratum corneum permeability to drugs would be improved enough not to be a rate-limiting process. RESULTS: To analyze the results obtained, a 4-compartment model, composed of donor cell, viable skin, muscle, and plasma compartments, was applied. Although the fitting lines obtained could describe the concentration-time profiles of antipyrine in each compartment very well, the concentration profiles in the contralateral tissues were extensively overestimated. Therefore, we developed a 6-compartment model which included the viable skin and muscle in the contralateral site, and analysed the concentration-time curve of each compartment. The fitting curves were in good agreement with the experimental data for all the compartments including the contralateral viable skin and muscle, and thus, this model was recognized to be adequate for the estimation of intradermal kinetics after topical application. Judging from the obtained values of clearance from viable skin to plasma and from viable skin to muscle, about 80% of antipyrine penetrated into viable skin, which suggested it was absorbed into circulating blood and 20% was transported to muscle under viable skin. CONCLUSIONS: Pharmacokinetic analysis using the 6-compartment model would be very useful for the estimation of local and systemic availability after topical application of drugs.

Administration, Topical↗