Cytotoxicity and manganese superoxide dismutase induction by tumor necrosis factor-alpha and ionizing radiation in MCF-7 human breast carcinoma cells

Both tumor necrosis factor-alpha (TNF) and ionizing radiation cause active-oxygen radical-mediated cell injuries and cell death. Thus cells treated by both TNF and radiation may suffer greater injuries than cells treated by either agent alone. On the other hand, TNF or radiation treatment can stimulate the expression of a mitochondrial superoxide scavenging enzyme, manganese superoxide dismutase (MnSOD), which can lower the cytotoxic effects of both agents. Thus, the induction of MnSOD by radiation may interfere with the cytotoxic action of TNF and vice versa. We used a human breast tumor cell line, MCF-7, to determine the interaction of TNF and radiation on cytotoxicity and MnSOD expression. TNF was found to be more effective as a cytotoxic agent when used before than after radiation treatment. These observations suggest that radiation induced-MnSOD was more effective in reducing the cytotoxic effect of TNF whereas TNF induction of MnSOD was less effective in counteracting the radiation action. Our results not only underscore the different effects of the treatment order of TNF and radiation, but also point to potential implication in the radiotherapy of breast tumors.

Combined treatments of heat, radiation, or cytokines with flavone acetic acid on the growth of cultured endothelial cells

The antitumour effects of flavone acetic acid (FAA) against a broad spectrum of established experimental tumours has been demonstrated. Damage to the vasculature, which rapidly disrupts blood flow and induces haemorrhagic necrosis, is believed to be a major mechanism contributing to the observed antitumour effects. Despite these established observations, FAA has shown little effect against human tumours. However, other applications of FAA, for examples, for an extended period of treatments or in combination with other antitumour modalities, have not been sufficiently explored. In order to test the direct effects of FAA on vasculature, endothelial cells isolated from human umbilical vein (HUVEC) and bovine pulmonary artery (CPAEC) were used in this study. FAA at the concentrations of 50 to 200 micrograms/ml causes reduction in cell number (from 20 to > 30% of the cells) of HUVEC as measured by MTT assay after 1, 3, and 5 h of treatment at 37 degrees C. FAA did not produce significant effects on similarly treated human squamous cell carcinoma, cell line UM-SCC-2. After 1 h treatment of FAA at 300 micrograms/ml, a large number of HUVECs failed to react with an actin stain, NBD-phallacidin. The growth of HUVECs and CPAEC in the presence of FAA for 1-3 days was progressively reduced. The number of HUVEC treated for 3 days at the concentrations of 100, 200, and 300 micrograms/ml were reduced by 75-86% in comparison with the control culture. The experiments with CPAEC showed similar results. The inhibition of the growth of endothelial cells by FAA was enhanced when it combines with tumour necrosis factor-alpha but not with interleukin-1, interferon-gamma, heat, or radiation. We observed that FAA can initiate both immediate effects and growth inhibition on cultured endothelial cells. These results support the notion that FAA rapidly induces vasculature damage. Furthermore, cytokines such as tumour necrosis factor-alpha can enhance the toxicity of FAA on endothelial cells.

The etiology of focal spinal arachnoiditis. An experimental study

Focal arachnoiditis and back pain have been attributed to potentially irritating substances leaking into the spinal canal from the lumbar intervertebral disc or facet joints. Through experimentation this hypothesis was tested: the nucleus pulposus (escaping from the intervertebral disc), lactic acid (from anaerobic glycolysis in the disc), chondroitin sulfate (a component of glycosaminoglycans in the disc), or synovial fluid (from degenerating facet joints) causes inflammation in the meninges if it contacts the dura mater. The test and control substances were injected into the epidural space of monkeys. Twelve weeks later the animals were killed; the dural sac was exposed by total lumbar laminectomy, grossly inspected, and then removed, fixed, sectioned, stained, and examined microscopically. Nucleus pulposus produced significant fibrosus in the arachnoid and epidural spaces; the other substances did not cause fibrosus or inflammation. The study suggests that leakage of nucleus pulposus into the epidural space causes an inflammatory response in the arachnoid and epidural spaces.

Vascularized iliac crest grafts: evaluation of viability status with marrow scintigraphy

Forty-three vascularized iliac crest grafts in the femoral neck region in 38 patients were assessed with marrow scintigraphy. Twenty grafting procedures had been performed for treatment of fractures, 16 for nontraumatic osteonecrosis, and seven for focal bone lesions. Scintiscans were obtained preoperatively and in the early and late postoperative period. Anterior images of the hips were obtained 30 minutes after intravenous injection of 4 mCi (148 MBq) of technetium-99m tin colloid by using a gamma camera with a low-energy, general-purpose collimator. The viable graft was detected as an area of tracer uptake corresponding to the configuration of the graft on radiographs. Marrow scintigraphy at 12 weeks showed that 24 grafts were viable, 11 were nonviable, and eight were indeterminate. Early and late results concurred in 36 of 43 (84%) grafts. Nonviable grafts occurred most frequently in fractures in the elderly. In seven patients who subsequently required total hip replacement, six grafts were nonviable while one was indeterminate at 12 weeks. Results indicate that marrow scintigraphy is useful in the treatment of patients with vascularized iliac crest bone grafts.

MR contrast enhancement: an experimental study in postlaminectomy epidural fibrosis

PURPOSE

To measure the effect of contrast medium dose, time elapsed since injection, and maturity of epidural scar tissue on the enhancement of scar tissue in MR imaging.

METHODS

We imaged 12 beagle dogs with MR at 10 to 60 days after lumbar laminectomy, and at necropsy we obtained exactly correlating histologic sections. Contrast enhancement of scar tissue at 2, 15, 40, and 60 minutes after 0.1 and 0.3 mmol of paramagnetic contrast medium per kilogram was measured. Contrast enhancement was analyzed with respect to the dose of contrast medium, the time of imaging, and the maturity of scar tissue.

RESULTS

Epidural scar tissue enhanced more intensely at 2 and at 15 minutes than at 40 or at 60 minutes. Consistently greater enhancement was observed with the dose of 0.3 mmol/kg than with the dose of 0.1 mmol/kg. Regions of loosely organized scar tissue enhanced less intensely and less quickly than did more organized scar tissue.

CONCLUSION

Contrast enhancement in scar tissue can be heightened by increasing the dose of contrast medium from 0.1 to 0.3 mmol/kg and by obtaining images within 15 minutes of injection.

Effect of tumour necrosis factor, heat, and radiation on the viability and microfilament organization in cultured endothelial cells

Normal blood vessels are leakage proof, non-adherent to blood cell elements, and participate actively in directional blood flow. These properties rely on the shape of endothelial cells and the integrity of the endothelial cell monolayer. The often observed effects of tumour necrosis factor-alpha (TNF) and hyperthermia on tumour tissue are the disruption of blood flow and an increase of vascular permeability. These agents are also known to affect the cytoskeletal organization and the cytoskeleton-dependent cellular functions. We observed that TNF (100 U/ml for 60 min) or heat (43 degrees C for 60 min) treatment causes the collapse of actin filaments in human umbilical vein endothelial cells (HUVEC). The combined treatment of TNF and hyperthermia intensifies the change of shape and loss of actin filaments. However, these changes are reversible within 24 h. These transient changes may contribute to the dysfunction and increased leakage of the microvasculature in tumours during and after these treatments despite the fact that the viability determined by MTT assay did not show a significant interaction between TNF and hyperthermia. Radiation (5 Gy) and TNF interact to a lesser extent compared with heat and TNF on cell shape and actin filament organization in HUVEC. Heat or radiation treatment enhances the expression of ELAM-1 mRNA in HUVEC while TNF produces the strongest effect on ELAM-1 mRNA expression. Our study suggests that radiation and heat affect endothelial cells and their subsequent functions differently. Result of an interaction between heat and TNF on endothelial cells supports the common notion that the anti-tumour effect by heat plus TNF treatments may benefit due to the increased disruption of vasculature function in the tumour.

Correlation of neuronal cell body size in motor cortex and hippocampus with body height, body weight, and axonal length

This study examined the comparative effects of body height and body weight on the neuronal cell size in humans and investigated their possible mechanisms. A total of 21 cases between the ages of 20 and 40 years were studied. Data on body height, body weight, and neuropathology were obtained from autopsy records. Mean cross sectional areas of cell bodies for 30 normal neurons were determined for the motor cortex projecting to lumbar spinal cord segments (L) 1-4 (Betz cells) as well as various regions of the hippocampus. Approximate axonal length of the motor neuron studied was measured from motor cortex to L2. We found that only motor cortex neuronal cell body size was significantly proportional to body height and the respective axonal length (p < .05). The findings indicate that: 1) body height has a greater effect than body weight on the motor neuron cell size, probably because of its association with axonal length; 2) the effect is regional (motor cortex) rather than general.

Molecular cloning of rat prostate transglutaminase complementary DNA. The major androgen-regulated protein DP1 of rat dorsal prostate and coagulating gland

Complementary DNA (cDNA) that codes for a major androgen-dependent secretory protein of rat coagulating gland and dorsal prostate, dorsal protein 1 (DP1), was isolated by molecular cloning. Recombinant DP1 cDNA clones were identified from a bacteriophage lambda gt11 rat coagulating gland expression library using an affinity purified polyclonal antibody. Amino acid sequence deduced from DNA contained sequences identical with several DP1 cyanogen bromide cleavage fragments. Northern blot hybridization of poly(A) RNA isolated from intact rat dorsal prostate and coagulating gland revealed a predominant messenger RNA (mRNA) species of approximately 3200 nucleotides. Tissue-specific expression of DP1 mRNA was indicated by the absence of DP1 mRNA in ventral prostate and other tissues of the rat. Expression of DP1 mRNA was androgen-dependent, decreasing approximately 80% 7 days after castration and increasing rapidly following androgen replacement. Southern blot analysis of restriction enzyme-digested rat DNA indicated that DP1 is encoded by a single gene and that no major genomic rearrangements accounted for its lack of expression in the dorsal prostate-derived rat Dunning tumor. Sequence comparisons revealed that rat prostate DP1 shares sequence identity with Factor XIIIa and tissue transglutaminase, including the active center, GQCWVF, indicating that DP1 is a member of the transglutaminase gene family.

Response elements of the androgen-regulated C3 gene

Intron and 5'-flanking regions of the androgen-regulated C3 subunit gene contain potential cis-acting transcription control sequences including several 15-base pair (bp) partial palindromes resembling response elements for glucocorticoid (GRE) and progesterone (PRE) receptors. Specific DNA binding of the androgen receptor (AR) and androgen-dependent activation of transcription indicate that some of these GRE/PRE-like sequences are capable of functioning as androgen response elements (ARE). A 0.3-kilobase pair (kbp) 5'-flanking fragment including the promoter region contains one such sequence (element A) and a 0.5-kbp region of the first intron contains two sequences (elements B and C). Androgen-dependent enhancement of transcription was assayed by cotransfection of CV1 cells with a rat AR expression vector, pCMVrAR, and C3 genomic fragments or synthetic elements cloned into the reporter vector ptkCAT. Enhancement of chloramphenicol acetyltransferase activity with the 0.5-kbp first intron fragment was 16 +/- 4-fold, while with the 0.3-kbp 5'-flanking fragment no response was detected and element C alone was greater than B or A. Binding of AR in the mobility shift assay correlated with androgen-dependent enhancement of chloramphenicol acetyltransferase activity. The intensity of transcriptional enhancement with the 0.5-kbp intron fragment suggested that other regulatory sequences within this intron region potentiated the ARE activities of elements B and C. ARE activity of the strongest C3 gene response element (C) was similar to that of a potent GRE (element M) of the mouse mammary tumor virus gene.

Normal and degenerating articular cartilage: in vitro correlation of MR imaging and histologic findings

Histologic correlation of the different magnetic resonance (MR) appearances of articular cartilage has not been studied extensively. Therefore, the authors correlated thin (high-resolution) MR sections of articular cartilage with histologic sections. Human cadaver lumbar facet joints were imaged with a 1-mm section thickness and a 4-cm field of view, then sectioned and stained for histologic comparison. MR imaging patterns were identified that correlated with normal cartilage and three histologically different patterns of degeneration.

Effect of lidocaine on the meninges in an experimental animal model

Arachnoiditis has been reported in patients who had received previous epidural injections of anesthetic agents. The purpose of this study was to determine if epidural injections of lidocaine are sufficient to cause arachnoiditis. Four monkeys that received a single epidural injection of lidocaine hydrochloride 1% were compared to four controls that had epidural injections of 0.9% saline. Four dogs that had multiple epidural injections of lidocaine hydrochloride 1% were compared to four controls that had multiple injections of saline. All animals were killed on the eighty-fourth day of the experiment. The dural sac, containing nerve roots and spinal cord, was removed intact from the lumbar spinal canal, fixed, sectioned, stained, and examined microscopically for evidence of arachnoid inflammation and fibrosis. No significant changes were found in the treated animals. Lidocaine hydrochloride 1% injected singly or repeatedly in the epidural space does not appear to be a cause of significant chronic meningeal reaction.

Positive pulse switching in coupled nonlinear Fabry-Perot cavities

It is shown that positive pulse switching is possible in a system of two coupled nonlinear Fabry-Perot cavities. The conditions in which a signal beam can be switched on and off by positive pulses in the steady state regime are described for cavities filled with Kerr media having a long diffusion length.

Hyperthermia enhances the cytotoxic effects of reactive oxygen species to Chinese hamster cells and bovine endothelial cells in vitro

Hyperthermia is under intensive investigation as a treatment for tumors both alone and in combination with other therapeutic agents. Hyperthermia has a profound effect on the function and structural integrity of tumor microvasculature; this has often been cited as a reason for its effectiveness in treatment of tumors. To test the role of hyperthermia in cytotoxic effects of active oxygen species, Chinese hamster, V79, and bovine endothelial cells were treated by the active oxygens, O not equal to 2 and H2O2, generated from the hypoxanthine/purine and xanthine oxidase reactions. It was found that cytotoxicity to V79 cells depends on the concentrations of purine and xanthine oxidase. A high level of cytotoxicity may be initiated in hyperthermia-treated tumors because high xanthine oxidase activity is known to be associated with tumors and endothelial cells, and degradation processes produce high concentrations of xanthine oxidase substrates in tumors. Since the cytotoxic effect can be reduced by the xanthine oxidase inhibitor, allopurinol, and the H2O2 removal enzyme, catalase, the cytotoxic effect in this experimental system is dependent on xanthine oxidase and H2O2. Adding erythrocytes at the same time as purine and xanthine oxidase could also prevent the cytotoxicity. Elevated temperatures stimulated the reaction of purine and xanthine oxidase and resulted in an increased cytotoxic effect. A similar effect is observed in growth inhibition and colony formation in endothelial cells without adding xanthine oxidase.(ABSTRACT TRUNCATED AT 250 WORDS)

Response of erythrocytes to heat in the presence of D2O, glycerol, and anisotonic saline

Mammalian erythrocytes that lack cytoplasmic organelles and a nucleus are a useful model for studying the effect of heat on the cell membrane and cytoskeleton. The effect of heat on the membrane bilayer and cytoskeleton of erythrocytes is remarkably similar to that observed in nucleated cells. Some concentrations of D2O and glycerol can effectively protect erythrocytes from heat-induced damage to the membrane and cytoskeleton. These results are similar to observations in nucleated cells. Heating erythrocytes in some concentrations of anisotonic NaCl solutions reduced damage, an observation that does not apply to enhanced killing of nucleated cells. This difference implies that some components of the cytoplasm or nucleus, or both, may contribute to the enhancement of cytotoxicity of nucleated cells when they are heated in the anisotonic NaCl solution. Incremental heating, dividing a heat treatment into two fractions, and preheating of erythrocytes all modify the effect of heat on erythrocytes slightly, but the results suggest little, if any, development of thermotolerance. The response of chicken erythrocytes is similar to that of mammalian erythrocytes, although higher temperatures are required to produce a heat effect in chicken erythrocytes. These observations suggest that the characteristic differences in heat sensitivity in nucleated and enucleated cells involve components other than the cell membrane.

Canine intervertebral disks: correlation of anatomy and MR imaging

Because the structure, maturation, and degeneration of canine intervertebral disks resemble those of humans, the authors developed a model of acute intervertebral disk degeneration in dogs. Herniated disks of 18 dogs were examined with magnetic resonance (MR) imaging and then sectioned with a freezing microtome. On the basis of their morphologic appearance in the freezing microtome sections, most of the lumbar intervertebral disks could be categorized as one of six types. Each type has characteristic features and a distinctive appearance on MR images. Findings of this study--including decreased signal intensity from the intervertebral disk, altered signal intensity in contiguous bone marrow, bulging of the anulus fibrosus, herniation of the nucleus pulposus, and contrast enhancement after intravenous administration of gadolinium diethylenetriaminepentaacetic acid (DTPA)--resemble observations from human clinical studies. Classification of degenerating disks and identification of MR imaging characteristics of each type may improve the interpretation of MR images and recognition of early disk degeneration in humans.

Age-related changes in the cervical facet joints: studies with cryomicrotomy, MR, and CT

The cervical facet joints of 20 cadavers were studied systematically with MR, CT, cryomicrotomy, and histologic sections to determine the anatomic changes that occur with age. Uniform layers of cartilage and subarticular cortical bone characterize the cervical facet joints in cadavers under 20 years of age. Most adult cervical facet joints have only a discolored or microscopically thin layer of cartilage and have irregularly thickened subarticular cortical bone. The appearance of the cervical facet joints changes significantly with aging.

Effect of repeated injections of chymopapain in the epidural space

Because arachnoiditis occurred in a previous experimental study, the authors performed additional experimental injections of chymopapain in the epidural space. Four monkeys received epidural injections of 100 units of chymopapain in 1.2 mL of saline on days 1, 8, and 16 of the experiment; four control animals received injections of 1.2 mL of 0.9% saline on the same days. Both groups were killed on the 84th day. The dural sac was removed, fixed, sectioned, stained, and examined microscopically. No significant changes were found in the arachnoid, dura, or epidural space of the treated animals. Chymopapain, even if injected repeatedly into the epidural space, does not cause significant scarring in the meninges.

Coupling of orthogonal polarization states in a nonlinear birefringent cavity

We discuss the coupling of orthogonally polarized beams in a nonlinear cavity and show experimentally how this can be used to implement gates or latches in which one polarization state is switched by another. These devices must be reset by interrupting a light beam and thus must dissipate energy to switch down. The possibility of up and down switching with positive pulses only is also discussed.

Age-related changes in the cervical facet joints: studies with cryomicrotomy, MR, and CT

The cervical facet joints of 20 cadavers were studied systematically with MR, CT, cryomicrotomy, and histologic sections to determine the anatomic changes that occur with age. Uniform layers of cartilage and subarticular cortical bone characterize the cervical facet joints in cadavers under 20 years of age. Most adult cervical facet joints have only a discolored or microscopically thin layer of cartilage and have irregularly thickened subarticular cortical bone. The appearance of the cervical facet joints changes significantly with aging.

Evidence that UGA is read as a tryptophan codon rather than as a stop codon by Mycoplasma pneumoniae, Mycoplasma genitalium, and Mycoplasma gallisepticum

Molecular cloning and sequencing showed that Mycoplasma gallisepticum, like Mycoplasma capricolum, contains both tRNA(UCA) and tRNA(CCA) genes, while Mycoplasma pneumoniae and Mycoplasma genitalium each appear to have only a tRNA(UCA) gene. Therefore, these mycoplasma species contain a tRNA with the anticodon UCA that can translate both UGA and UGG codons.

Correlation of computed tomography and postmortem findings of a diffuse astrocytoma: a case report

Diffusely infiltrating astrocytomas often present diagnostic difficulties. We herein correlate the radiologic and postmortem findings of a diffuse astrocytoma and conclude that recognition of abnormal bilateral and fairly symmetric enlargement and increased density of normal structures in CT scans may lead to an antemortem diagnosis of the tumor.

Primary structure and androgen regulation of a 20-kilodalton protein specific to rat ventral prostate

Nuclear and cytosolic forms of a 20-kdalton rat ventral prostate protein were purified and partially sequenced from their N-termini. Isolated nuclei were treated with micrococcal nuclease and extracted in 0.6 M NaCl, and proteins were separated by affinity chromatography on Matrex gel green A, ammonium sulfate fractionation, and fast protein liquid chromatography on Superose 12. The 43 amino acid N-terminal sequence of the nuclear 20-kdalton protein was identical with the cytosolic protein except it lacked 7 N-terminal amino acids present in the cytosolic form. The DNA sequence of a full-length complementary DNA clone isolated from a ventral prostate gt11 library extended the N-terminal sequence of the cytosolic form by an additional nine amino acids from the predicted initiation methionine. The cDNA included the nucleotide sequence for the 43 amino acid N-terminal sequence of the purified 20-kdalton protein and predicted molecular weights of 16,686, 17,521, and 18,650, respectively, for the nuclear, cytoplasmic, and nonprocessed proteins. Northern blot analyses of reproductive tract tissue RNAs using the 20-kdalton protein cDNA as probe revealed a single mRNA species of 0.92 kb detectable only in extracts of rat ventral prostate. Expression of the 0.92-kb mRNA was androgen dependent since the mRNA was undetectable in extracts obtained 4 days after castration and was restored 16 h after restimulation with androgen.