Action of dexmedetomidine on rat locus coeruleus neurones: intracellular recording in vitro

The action of dexmedetomidine on rat locus coeruleus neurones was examined using intracellular recordings from the in vitro brain slice preparation. Concentrations of dexmedetomidine from 1 to 1000 nM were tested. At 30 nM, dexmedetomidine produced complete inhibition of firing of all neurones tested (n = 21); this was associated with a 13 mV hyperpolarization (range 2.2-29.7 mV, n = 21) and a 27% reduction in input resistance (range 11.1-46.2%, n = 17). The dexmedetomidine responses reached a plateau phase between 100 and 1000 nM. Based on single-cell recordings, the hyperpolarizing potency of dexmedetomidine was found to be 6 times greater than that of clonidine (n = 10). The reversal potential for the dexmedetomidine-induced hyperpolarization was -106.9 +/- 1.7 mV (n = 9), a value similar to the K+ equilibrium potential; hyperpolarization was blocked by both CsCl and BaCl2. The effect of dexmedetomidine was antagonized by yohimbine, with a dissociation equilibrium constant of 30 nM. In contrast, prazosin, the alpha 1-, alpha 2B- and alpha 2C-adrenoceptor subtype-preferring ligand, did not inhibit the dexmedetomidine effect. Our results also show that low concentrations of oxymetazoline (10-300 nM), an alpha 2A-adrenoceptor subtype-selective drug, cause profound inhibition of neuronal activity in the locus coeruleus. These data therefore suggest that dexmedetomidine binds to alpha 2A-adrenoceptors on the cell membrane of neurones of the locus coeruleus and that this leads to opening of the inwardly rectifying K+ channels, resulting in the observed hyperpolarization of the membrane.

Conformational properties of four peptides spanning the sequence of hen lysozyme

Four peptides encompassing the entire amino acid sequence of hen lysozyme were examined in aqueous solution and in 50% (v/v) 2,2,2-trifluoroethanol (TFE) by far-UV CD. Two peptides, 1-40 and 84-129, correspond to regions which are helical in the native protein, and together represent the alpha-domain. The beta-domain of the native enzyme was also synthesized as two peptides, one (41-60) containing the residues in the triple stranded antiparallel beta-sheet and the other (61-82) corresponding to a region lacking regular secondary structure. In water at pH 2.0 and 25 degrees C, the monomeric peptides 1-40, 41-60 and 61-82 appear to be predominantly unstructured. By contrast, the peptide 84-129 has considerable, presumably helical structure, corresponding to approximately 19%, or nine residues, on average, which can be unfolded by the addition of 8 M urea or 6 M guanidine hydrochloride. In 50% TFE the conformational properties of the four peptides are again distinct. Although little helical structure is induced in the peptides 41-60 and 61-82, and a native-like extent of helical structure is induced in the peptide 1-40, the peptide 84-29 converts almost entirely to helical structure in 50% TFE. The far-UV CD spectrum of a stoichiometric mixture of the four peptides in water resembles closely that of a denatured state of the intact protein formed by reductive methylation of its four disulphide bonds, but differs significantly from that of the native protein. The far-UV CD spectrum of the peptide mixture in TFE is indistinguishable from that of the intact protein in this solvent, both in the presence and in the absence of its four disulphide bonds. The conformational preferences of the peptides are not predicted using standard assessments of helical propensity or hydrophobicity, but correlate instead with the number of local contacts made in the native protein. On the basis of these results, we suggest that the region 84-129 could play an important role in determining the nature of the early folding events in the folding pathway of the intact polypeptide chain.

Animal models in ANCA-vasculitis

The animal models described to date suggest pathogenicity of ANCA. Unfortunately, none of the models unequivocally proves that ANCA are pathogenic. Further search for a suitable animal model to document or exclude causal significance of ANCA in vasculitis is needed.

Transformation-restoring factor: a low molecular weight secreted factor required for anchorage-independent growth of oncogene-resistant mutant cell lines

We have previously described two independent mutant rat fibroblast cell lines that fail to form colonies in soft agar when infected with a v-H-ras-expressing retrovirus, yet still undergo transformation-related morphological alterations in response to this oncogene. We report here that conditioned medium (CM) from non-transformed rat fibroblasts contains an activity that specifically corrects this defect in the mutant cell lines, rendering them capable of anchorage-independent growth in response to ras. The major activity in CM, designated transformation-restoring factor (TRF), is approximately 1300 molecular weight, lipid insoluble, and heat, protease, acid and base stable. Latent activity, distinct from TRF, is also present in CM; several lines of evidence indicate that transforming growth factor (TGF) beta is responsible for this activity. TRF, however, cannot substitute for TGF beta in the phenotypic transformation of NRK cells. TRF activity is decreased in CM of control cells transformed by ras and this response to ras is retained by the mutant cell lines. We propose that whereas wild-type cells transformed by ras may constitutively activate a TRF-regulated pathway, thus becoming independent of TRF for growth in soft agar, these mutants have acquired dependence on an exogenous supply of TRF for this aspect of the transformed phenotype. Cellular activities regulated, directly or indirectly, by TRF may be effectors of the anchorage-independent growth property that is a hallmark of transformed rodent fibroblasts.

Physicochemical characterization of the cytoplasmic domain of the epidermal growth factor receptor and evidence for conformational changes associated with its activation by ammonium sulphate

The physiochemical properties of the purified cytoplasmic domain of the epidermal growth factor (EGF) receptor, its self-phosphorylation and peptide phosphorylation activities, and its activation by ammonium sulphate have been studied. Highly efficient purification procedures for the isolation of the recombinant cytoplasmic domain (Met644-Ala1186) of the EGF receptor, expressed in the baculovirus/insect cell system, are described. Physicochemical characterization of the protein included investigation of its isoelectric and hydrodynamic properties, stability, oligomeric status, and secondary structure using far-u.v. circular dichroism. The recombinant protein was not recognized by anti-phosphotyrosine antibodies, unless first self-phosphorylated in vitro. Tryptic phosphopeptide maps of self-phosphorylated recombinant cytoplasmic domain and the EGF-stimulated A431-membrane receptor were very similar, suggesting that the recombinant had similar self-phosphorylation capacity and specificity. The preparations were characterized by high specific activity towards peptide tyrosine phosphorylation. Although the cytoplasmic domain was isolated as a homogeneously monomeric protein, storage at 4 degrees C led to slow, spontaneous aggregation with reduction in specific activity. Both high activity and monomeric state were maintained by storage below 0 degree C. The dependence of the initial rate of self-phosphorylation on protein concentration was consistent with cross-phosphorylation but not with the known oligomerization-induced activation of holoreceptor. The peptide phosphorylation activity was stimulated by Mn2+, Mg2+ and (NH4)2SO4 at high concentrations. The substrate specificity of (NH4)2SO4 activation was studied using synthetic peptides. Self-phosphorylation was inhibited by (NH4)2SO4 in the range 0-0.25 M but activated at 1.0-1.5 M, possibly as a result of ionic and hydrophobic protein interactions respectively. Phosphopeptide maps of cytoplasmic domain phosphorylated in the presence of high (NH4)2SO4 showed that the protein was more extensively phosphorylated than in the absence of salt, or than the native receptor. Far-u.v. circular-dichroism spectra of the cytoplasmic domain changed dramatically at 1 M (NH4)2SO4, raising the possibility that (NH4)2SO4 activates the kinase catalytic domain by inducing conformational changes.

Expression of insulin-like growth factor II in hepatitis B, cirrhosis and hepatocellular carcinoma: its relationship with hepatitis B virus antigen expression

Expression of insulin-like growth factor II in two human hepatocellular carcinoma cell lines and in hepatitis B, cirrhosis and hepatocellular carcinoma in 419 cases were investigated, and its relationship with the expression of hepatitis B virus X gene was studied by means of immunohistochemical and electron microscopic techniques. The results demonstrated that hepatocellular carcinoma cells (SMMC 7721 and QGY 7703) in culture could express insulin-like growth factor II. Expression seemed to be regulated by cell density, which was suggested as the molecular basis of the contact inhibition of cell proliferation. In tissue sections, cells with high expression of insulin-like growth factor II were observed not only in hepatocellular carcinoma (93%) but also in 95% of the pericancerous liver tissues, 72% of cirrhotic livers, 64% of chronic active hepatitis and 37% of chronic persistent hepatitis. In most cases of hepatocellular carcinoma, insulin-like growth factor II was localized in the cytoplasm of the cancer cells. In the benign liver disorders, four types of cells that highly expressed insulin-like growth factor II were observed: (a) a kind of small liver cell we named the small polygonal liver cell; (b) multinuclear giant hepatocytes; (c) hepatocytes in most of hyperplastic and neoplastic nodules, small hepatocyte nodules and some of regenerative nodules; and (d) some proliferating ductular cells. Even more interestingly, insulin-like growth factor II expression was shown to be closely related to the expression of hepatitis B virus X gene product. We suggest that the activation of insulin-like growth factor II gene and its overexpression may be a crucial step in the processes of hepatitis B virus-associated hepatocarcinogenesis and that the X gene product may activate the insulin-like growth factor II gene through a transactivation mechanism. In addition, we studied the characteristics of small polygonal liver cells, and the roles they may play in the regeneration and carcinogenesis of hepatitis B virus-infected liver are discussed.

Immune complex glomerulonephritis is induced in rats immunized with heterologous myeloperoxidase

Anti-neutrophil cytoplasmic antibodies (ANCA), including anti-myeloperoxidase (MPO) antibodies, are associated with pauci-immune necrotizing small vessel vasculitis or glomerulonephritis. In order to substantiate a pathogenic role for ANCA, an animal model of pauci-immune ANCA-induced glomerulonephritis or vasculitis is required. Brouwer et al. reported pauci-immune glomerulonephritis in rats immunized with human MPO followed by perfusion of kidneys with lysosomal enzyme extract combined with H2O2, and suggested that this could serve as a model of ANCA-induced disease. We repeated these studies in spontaneously hypertensive rats (SHR) and Brown Norway rats (BNR). We immunized rats with human MPO. When circulating anti-MPO antibodies were detectable by indirect immunofluorescence microscopy and ELISA, blood pressure was measured, then perfusion of the left kidney of each rat was done via the renal artery in a closed, blood-free circuit with either MPO + H2O2, MPO, H2O2 alone or MPO + H2O2 + neutral protease. Rats were killed on day 4 or day 10 after perfusion, and specimens were examined by light and immunofluorescence microscopy. Pathological lesions and deposits of IgG, C3, and MPO were found in immunized rats perfused with MPO + H2O2 with or without neutral protease, or MPO alone, in both rat strains and on both day 4 and day 10. The degree of histologic injury was proportional in intensity to the amount of IgG immune deposits. Spontaneously hypertensive rats sustained more damage and higher blood pressure than Brown Norway rats. No lesion was observed in immunized rats perfused with H2O2 or in the non-perfused right kidneys. Some of the non-immunized rats perfused with MPO + H2O2 developed pathological lesions. In conclusion, these rat models are examples of immune complex-mediated glomerulonephritis, and therefore are not similar to human ANCA-associated disease.

Far-UV circular dichroism reveals a conformational switch in a peptide fragment from the beta-sheet of hen lysozyme

The conformation of a 20-residue synthetic peptide corresponding to the antiparallel triple-stranded beta-sheet in hen egg white lysozyme (residues 41-60) has been studied by circular dichroism (CD) and size-exclusion chromatography. In aqueous solution the conformation of the peptide is strongly pH dependent. At pH values below 4.0 and 25 degrees C, the far-UV CD spectrum of the peptide resembles that expected for a predominantly beta-sheet structured (low-pH form), while at pH values exceeding 4.0 the spectrum changes to that of a predominantly unstructured conformation (high-pH form). The far-UV CD spectrum of the high-pH form (pH 6.8) is not affected by changes in the concentration of the peptide and by changes in temperature and ionic strength. By contrast, the far-UV CD spectrum of the low-pH form (pH 2.0) is concentration and temperature dependent but is not affected by ionic strength. Size-exclusion chromatography trimers and higher oligomers and that the monomeric form of the peptide at low pH is predominantly random in nature. Significant helical structure was induced in the high-pH form of the peptide by both trifluoroethanol (TFE) and methanol; by contrast, the conformation of the low-pH form of the peptide was not changed with concentrations of methanol up to 50% (v/v), although in the presence of TFE a state displaying significant helical character was induced. During the transition an intermediate which also displays significant beta-sheet character but which has a distinct CD spectrum is populated. The relevance of this study to the folding pathway of the intact protein is discussed.

Stimulation of the nigrostriatal dopamine system produces hypertension and tachycardia in rats

To test for the ability of the nigrostriatal dopamine (DA) system to influence cardiovascular function, experiments were carried out to assess the effects of electrical or chemical stimulation of the nigrostriatal DA system on arterial blood pressure, heart rate, and striatal DA release in anesthetized rats. Electrical stimulation of the substantia nigra pars compacta (SNC), in addition to enhancing the DA release in the corpus striatum (CS), elicited proportional hypertension and tachycardia. This could be mimicked by microinjection of two excitatory amino acids, kainic acid and glutamate, into the SNC area of rat brain. The SNC stimulation-induced hypertension, tachycardia, and increased striatal DA release were attenuated by prior destruction of the nigrostriatal DA system produced by intramedial forebrain bundle injection of 6-hydroxydopamine and by prior blockade of postsynaptic DA receptors produced by intra-CS injection of DA receptor antagonists, haloperidol or pimozide. The SNC stimulation-induced hypertension was attenuated by spinal transection, whereas the SNC stimulation-induced tachycardia was attenuated by bilateral vagotomy. The data suggest that stimulation of the nigrostriatal DA system produces both hypertension and tachycardia in rats.

Kinetics of hydrolysis of dansyl peptide substrates by thermolysin: analysis of fluorescence changes and determination of steady-state kinetic parameters

The stopped-flow fluorescence technique has been used to study the hydrolysis of 10 dansyl peptides by thermolysin. The origin of the fluorescence changes observed during the reactions has been investigated in detail. Depending on the substrate and the excitation wavelength, the dansyl fluorescence changes observed arise either from energy transfer (maximal at lambda ex = 230 and 280 nm) between Trp residues of thermolysin and the dansyl group of the substrate in enzyme-substrate (ES) complexes or from both sources. These excitation (maximal at lambda ex = 245 and 340 nm) of the free substrate and product, or from both sources. These two types of fluorescence signals reflect the concentrations of ESi and free substrate, respectively. Both types of fluorescence changes have been used to monitor the reaction progress, and different mathematical formalisms have been used to determine the kinetic parameters for the reactions with results that are in good agreement. The efficiency of Trp quenching by a series of five dansyl tripeptides is shown to be related to the fractional saturation of enzyme and follows the KM-1 values for the substrates. The quenching efficiency for a dansyl tetrapeptide is weaker due to the greater distance between the dansyl group and the Trp-115 donor in thermolysin. On the basis of these studies, substrates capable of supporting more detailed kinetic studies of thermolysin have been identified.

Differential effect of halide anions on the hydrolysis of different dansyl substrates by thermolysin

The effect of sodium halide salts on the hydrolysis of three of the dansyl (Dns) peptide substrates described in the previous paper (Yang & Van Wart, 1994) by thermolysin have been studied. Increasing concentrations of sodium chloride decrease the KM value for the hydrolysis of the tripeptides Dns-Gly-Phe-Ala and Dns-Ala-Phe-Ala but leave kcat unaltered. This kinetic behavior is described by a nonessential activation mechanism in which chloride binds preferentially to the enzyme-substrate complex. Similar trends are found for the sodium bromide and fluoride salts. In contrast, sodium chloride decreases both KM and kcat almost equally for the hydrolysis of Dns-Ala-Ala-Phe-Ala, leaving kcat/KM unchanged. Thus, chloride is an uncompetitive inhibitor of this substrate. Molecular modeling studies have been carried out in order to explain the effect of chloride on the binding of these dansyl peptides. The decrease in KM for the hydrolysis of all three substrates is attributed to an interaction of chloride with Arg-203 located in the active site to stabilize the enzyme-substrate complexes. The differential effect of chloride on the kcat values for the hydrolysis of the dansyl tripeptides vs dansyl tetrapeptide is related to differences in binding on the Pn side of the substrates. The tripeptides are predicted to bind to the active site of thermolysin in a single low-energy conformation. However, there are two populations of low-energy binding modes for the tetrapeptide, one of which is believed to be a more productive binding mode.(ABSTRACT TRUNCATED AT 250 WORDS)

[Deposition of air particles with polycyclic aromatic hydrocarbons (PAH) in human respiratory tract]

Atmospheric concentrations of five sizes of particles with PAH were determined in Taiyuan, and deposition of PAH in human respiratory tract was estimated. Results showed 47%-70% of air PAH concentrated in the particles less than 2 microns in diameter. Total PAH deposition in respiratory tract measured 12. 53 micrograms per day, and 53% of them deposited in nasopharyngeal region, 65% in tracheobronchial region and 32% in alveoli.

Arterial baroreceptor information affects striatal dopamine release measured by voltammetry in rats

The effects of altering the arterial blood pressure on the extracellular levels of dopamine in the corpus striatum, measured using nafion-coated C fiber electrodes combined with differential pulse amperometry, were assessed in urethane-anesthetized rats. The striatal dopamine release was increased by increasing the carotid blood pressure with phenylephrine injection but decreased by decreasing the carotid blood pressure with bilateral carotid occlusion. The data indicate that baroreceptors inputs affect the striatal dopamine release in rats.

Simulation of stochastic micropopulation models--I. The SUMMERS simulation shell

A generic, abstract model and the simulation shell based on it, both called SUMMERS, are used as a framework for the implementation of stochastic micropopulation models; in these, each individual is followed separately while moving through a sequence of states. The shell supports groups of interacting members, individual characteristics and multiple simultaneous activities. Stochastic decisions may be made using Monte Carlo rules. Keywords control the simulations and the reports generated. A sensitivity analysis utility allows assessment of the dependency of outcomes on model features. Extensive use has been made of software engineering techniques. Specializations of SUMMERS are described in subsequent papers.

Simulation of stochastic micropopulation models--II. VESPERS: epidemiological model implementations for spread of viral infections

This second paper concerning stochastic micropopulation simulations describes VESPERS, which can serve as a framework for simulation models of the epidemic spread of infection. The versions described are implemented using the simulation shell, SUMMERS, which includes the generic commonalities of several micropopulation models. Population members in VESPERS move through states related to the individual's status relative to the infective agent. Features of the models include mixing groups, member demographics, susceptibility and infectiousness, and co-circulation of infectious agents. The sensitivity of the simulation outcomes to quantitative features of the model has been analyzed. The user can select reports of desired distributions and averages of simulation outcomes.

Parameter sensitivity of a model of viral epidemics simulated with Monte Carlo techniques. I. Illness attack rates

This is the first of a series of papers concerning sensitivity analyses of stochastic micropopulation models. A model of epidemic spread of viral infection is used in this series to illustrate the principles and performance of the sensitivity analysis system. For these studies the analysis system now known as SENSEN was redesigned and extended to use the principles and modules of the SUMMERS simulation shell. The latter was used in the implementation of the epidemic model as well as a number of others. The SENSEN system can be used with any of these. The advantages of sensitivity analysis for stochastic micropopulation models are discussed. Its general form and operation are illustrated by a comparison of illness attack rates with infection attack rates.

Evaluation of the anti-inflammatory and liver-protective effects of anoectochilus formosanus, ganoderma lucidum and gynostemma pentaphyllum in rats

The pharmacological effects of Anoectochilus formosanus, Ganoderma lucidum and Gynostemma pentaphyllum were studied against carrageenan-induced paw edema and CC1(4)-induced hepatotoxicity in rats. The water extracts of G. pentaphyllum and G. lucidum were found to possess significant anti-inflammatory activity against carrageenan induced edema. The administration of Gynostemma pentaphyllum displayed an activity even more potent than indomethacin. In contrast, Anoectochilus formosanus showed a delayed onset of anti-inflammatory activity starting from 4 hrs post carrageenan administration. However, A. formosanus significantly decreased the acute increase in serum GOT and GPT level caused by CC1(4). Histological changes such as necrosis, fatty change, ballooning degeneration, inflammatory infiltration of lymphocytes and Kupffer cells around the central vein were simultaneously improved by the treatment of A. formosanus.

[Acute purulent pericarditis: clinical experience with primary pericardiectomy plus continuous pericardium lavage]

106 patients with acute purulent pericarditis were treated surgically with three different methods without operative mortality. The pericardiectomy plus continuous pericardial lavage was more effective than pericardiectomy without irrigation or simple pericardial drainage in several aspects, such as recovery of body temperature, elimination of infectious-toxic symptoms and cutting short hospitalization days. Besides, cardiac tamponade or late constriction of the pericardium could be avoided.

Pathologic findings associated with interleukin-2-based immunotherapy for cancer: a postmortem study of 19 patients

The use of interleukin-2 (IL-2), either alone or in combination with lymphokine-activated killer cells, tumor infiltrating lymphocytes, or other immunotherapeutic agents has added a new list of alternatives to conventional antineoplastic regimens. Little information is available about the pathologic changes occurring in patients treated with these agents. In this study, we reviewed the necropsy materials from 19 patients, 12 men and 7 women, with a variety of malignancies including melanoma, renal cell carcinoma, gastrointestinal and pulmonary adenocarcinoma, and metastatic gastrinoma, who died after receiving IL-2-based immunotherapy. Death occurred at intervals ranging from less than 1 hour to 143 days following the last dose of therapy. All patients dying at or less than 43 days following cessation of therapy had lymphoid infiltrates of varying intensity in residual tumor. At necropsy, the major cause of death unrelated to the presence of metastatic tumor was bacterial sepsis. In addition, we found evidence of significant cardiac and pulmonary toxicity: two patients with acute myocardial infarction, one with and one without significant coronary artery disease, two cases of unexplained lymphocytic myocarditis, and one case of fatal pulmonary capillary plugging following an infusion of lymphokine-activated killer cells. Thus, not unlike other forms of therapy for cancer, IL-2-based immunotherapy does not appear to be without significant toxicity.

Primary renovascular effects of erythromycin in the rat: relationship to cyclosporine nephrotoxicity

Erythromycin is known to exacerbate cyclosporine nephrotoxicity. This has been attributed to the potential of erythromycin to reduce the hepatic microsomal metabolism and clearance of cyclosporine. Erythromycin may also be nephrotoxic. We tested the hypothesis that erythromycin may have direct effects on the renal vasculature which are additive or synergistic with the effects of cyclosporine. Sprague-Dawley rats were administered graded doses of either erythromycin, 2.5, 5, 7.5, and 10 mg/kg BW/min i.v. over consecutive 10-min intervals; cyclosporine, 1, 2, 3, and 4 mg/kg BW/min i.v. over consecutive 10-min intervals; or both drugs simultaneously. In separate experiments, identical doses of erythromycin or cyclosporine were infused intravenously following acute unilateral renal denervation. Infusion of erythromycin led to an initial decline in arterial blood pressure whereas infusion of cyclosporine resulted in a dose-related increase in arterial blood pressure. Despite these different systemic effects, each drug alone produced a striking decrease in renal blood flow. This effect was more pronounced when the drugs were infused concomitantly. The reduction in renal blood flow occurred in an additive manner as a direct consequence of increased renal vascular resistance. Prior renal denervation did not modify the response to either erythromycin or cyclosporine. These results demonstrate that cyclosporine-induced vasoconstriction is exacerbated by erythromycin and suggest that the decline in renal function observed in patients coadministered these drugs may be due in part to additive renovascular toxicity.

LINKERS: a simulation programming system for generating populations with genetic structure

Significant features are described of a Monte Carlo simulation system, LINKERS, that generates nuclear family data conforming to one locus and two loci genetic models. Software engineering techniques help to produce a user friendly environment for studies of genetic ascertainment. LINKERS' 39 code modules are maintained and optimized using VAXset. Within a VAX/VMS workstation environment LINKERS generates a useful population of 10,000 families in 1 min. An example is presented to illustrate the use of LINKERS. Generated data were analysed using the segregation program POINTER. Likelihood ratio tests showed the effects of multiple alleles, gene frequency and incorrect specification of disease prevalence.

Functional and psychosocial effects of multimodality limb-sparing therapy in patients with soft tissue sarcomas

We have documented functional and psychosocial changes in patients with extremity soft tissue sarcomas who have undergone multimodality limb-sparing treatments. In 88 patients, parameters related to economic status, sexual activity, pain, limb function, and global quality of life (QOL) were recorded prior to surgery and every 6 months postoperatively. Changes from the preoperative assessment for every parameter were analyzed in each patient. Six months after surgery, there was a decrease in employment status, sexual activity, and in limb function in a significant number of patients. At 12 months, these decreases were still evident. Despite these changes, global QOL measured by a standardized test showed at least some improvement in a significant proportion of patients at 12 months. These findings highlight the difficulty in defining QOL. It could not be ascertained if radiation therapy and/or chemotherapy were causative factors in specific changes because of the small numbers of patients in each subgroup. However, among 60 patients with high-grade sarcomas, significant wound problems developed in 10 of 33 who received postoperative radiation therapy in combination with adjuvant doxorubicin and cyclophosphamide chemotherapy compared with one of 27 patients who received adjuvant chemotherapy alone (P = .016). Also, among high-grade sarcoma patients with 12-month follow-up, six of 19 patients who received radiation therapy and chemotherapy developed joint contractures compared with zero of 15 patients who received chemotherapy alone (P less than .04). The combination of postoperative radiation therapy and chemotherapy appeared to be associated with significantly more tissue-related injury in patients with high-grade sarcomas compared with chemotherapy alone.