Normal human mesothelial cells and mesothelioma cell lines express insulin-like growth factor I and associated molecules

Insulin-like growth factor (IGF) I has important growth regulatory functions in normal growth and development. IGF-I is also a mitogen for a number of cancer cell lines; however, its autocrine effect has not been well established. In this study, the expression of IGF-I, its receptor, and its major serum-binding protein were examined in 5 normal human mesothelial (NHM) cell samples and 11 pleural mesothelioma cell lines. All NHM cells and mesothelioma cell lines expressed IGF-I, IGF-binding protein 3 (IGFBP-3), and IGF-I receptor mRNA by either Northern blot or reverse transcription polymerase chain reaction analysis. IGF-I (0.136 +/- 0.024 ng/ml, mean +/- SEM) and IGFBP-3 (18.5 +/- 3.2 ng/ml) proteins were readily detected in the conditioned medium of mesothelioma cell lines but were not greater than corresponding measurements in that of NHM cells (IGF-I, 0.120 +/- 0.080 ng/ml; IGFBP-3, 15.9 +/- 1.3 ng/ml). Exogenous recombinant IGF-I stimulated cell proliferation of NHM cells, demonstrating the presence of a functional IGF-I receptor. Our results suggest that IGF-I may function as an autocrine growth stimulus in normal proliferating mesothelial cells, which may contribute to their malignant transformation.

Increased biliary transferrin excretion following parenteral aluminium administration to rats

Aluminium accumulates in the livers of patients receiving either parenteral nutrition or haemodialysis. When given parenterally to rats, aluminium causes cholestasis. However, the mechanism of hepatic aluminium uptake and the fate of aluminum in the liver are poorly understood. We examined the effect of parenteral aluminium administration on biliary excretion of transferrin, the major circulating aluminum-binding protein. Male Wistar rats were given parenterally aluminum 5 mg/kg/day for 1-14 days. Bile was collected for 3 hr at the end of the study period. Biliary total protein concentration and IgA/total protein were unaffected by up to 14 days of parenteral aluminium administration. However, biliary transferrin excretion increased with duration of aluminum administration up to five-fold by day 14. Biliary transferrin concentration and transferrin/total protein was higher in aluminum treated rats than controls after 7 and 14 days of study. Hepatic aluminum concentration reached a maximum after 4 days of parenteral aluminum administration, at which time serum bile acid and alanine amino transferase values were not different from controls. Since biliary transferrin is normally derived from the serum, it is likely that aluminum promotes hepatocellular uptake of transferrin and that aluminum enters the hepatocyte bound to transferrin. We postulate that transferrin may direct aluminum to intracellular sites where its toxic effects would be minimized.

Glutathione S-transferase pi facilitates the excretion of arsenic from arsenic-resistant Chinese hamster ovary cells

We have previously demonstrated that glutathione S-transferase pi (GST pi) is overexpressed in SA7 cells, an arsenic resistant cell line derived from Chinese hamster ovary (CHO) cells. Our present results show that SA7 cells accumulate less arsenic than parental CHO cells and partially revertant SA7N cells. The lower levels of arsenic accumulation in SA7 cells resulted from their faster excretion rates. However, the excretion of arsenic from SA7 cells was significantly inhibited by the GST inhibitors ethacrynic acid and Cibacron blue. Furthermore, when GST pi levels in SA7N cells were re-elevated by zinc sulfate pretreatment, arsenic accumulation decreased and arsenic excretion increased to levels similar to those in SA7 cells. These results suggest that GST pi can facilitate the excretion of arsenic. Such facilitation by GST pi is unlikely to be associated with multi-drug resistant P-glycoprotein, since no overexpression of P-glycoprotein was detected in SA7N and SA7 cells.

Mechanisms of stimulation of interleukin-1 beta and tumor necrosis factor-alpha by Mycobacterium tuberculosis components

The granulomatous immune response in tuberculosis is characterized by delayed hypersensitivity and is mediated by various cytokines released by the stimulated mononuclear phagocytes, including tumor necrosis factor-alpha (TNF alpha) and IL-1 beta. We have demonstrated that Mycobacterium tuberculosis cell wall component lipoarabinomannan (LAM), mycobacterial heat shock protein-65 kD, and M. tuberculosis culture filtrate, devoid of LPS as assessed by the Amebocyte Lysate assay, stimulate the production of TNF alpha and IL-1 beta proteins and mRNA from mononuclear phagocytes (THP-1 cells). The effect of LAM on the release of these cytokines was specific, as only LAM stimulation was inhibited by anti-LAM monoclonal antibody. Interestingly, we found that LAM and Gram-negative bacterial cell wall-associated endotoxin LPS may share a similar mechanism in their stimulatory action as demonstrated by inhibition of TNF alpha and IL-1 beta release by monoclonal antibodies to CD14. Anti-CD14 monoclonal antibody MY4 inhibited both TNF alpha and IL-1 beta release with LAM and LPS but no effect was observed with other mycobacterial proteins. An isotype antibody control did not inhibit release of cytokines under the same experimental conditions. M. tuberculosis and its components upregulated IL-1 beta and TNF alpha mRNAs in THP-1 cells. Nuclear run-on assay for IL-1 beta demonstrated that LAM increased the transcription rate. The induction of IL-1 beta was regulated at the transcriptional level, in which these stimuli acted through cis-acting element(s) on the 5' flanking region of the IL-1 beta genomic DNA. M. tuberculosis cell wall component LAM acts similarly to LPS in activating mononuclear phagocyte cytokine TNF alpha and IL-1 beta release through CD14 and synthesis at the transcriptional level; both cytokines are key participants in the host immune response to tuberculosis.

Pedicle fixation: an adjuvant for the treatment of thoracolumbar metastases

For a long time, radiotherapy was considered as the best treatment for spinal metastases. However, radiotherapy alone could not resolve the problem of pathological fracture which is an important complication of spinal metastases. In this paper, we introduce pedicle fixation system as an adjuvant to radiotherapy to treat eight patients with thoracolumbar metastases. The result was encouraging that all the patients achieved spinal stabilisation and all but one had immediate postoperative relief of back pain. The operation time was short and none of the patients required a blood transfusion. Tissue diagnosis was possible through this approach.

Enhanced IL-1 beta and tumor necrosis factor-alpha release and messenger RNA expression in macrophages from idiopathic pulmonary fibrosis or after asbestos exposure

Idiopathic pulmonary fibrosis (IPF) and asbestosis are fibrotic interstitial lung diseases characterized by alveolar wall fibrosis with accumulation of extracellular matrix, interstitial remodeling, and increased numbers of activated alveolar macrophages. Animal models and in vitro studies have shown that macrophage cytokines, namely IL-1 beta and TNF-alpha, play significant roles in the development of fibrosis. We found significant increases for TNF-alpha release in both diseases (p < 0.01) and a significant increase for IL-1 beta release in asbestosis compared to normal controls (p < 0.01). Also, the mRNA expression of these cytokines was increased in alveolar macrophages from patients with IPF or asbestosis compared with normals. The level of TNF-alpha release in macrophage supernatants correlated with the number of neutrophils per milliliter bronchoalveolar lavage fluid returned. Chrysotile, crocidolite, amosite asbestos, and silica stimulated IL-1 beta and TNF-alpha release and up-regulated their respective mRNA in macrophages or monocytes. To evaluate the role of IL-1 beta and TNF-alpha in the accumulation of extracellular matrix, we studied collagen types I and III and fibronectin gene expression in human diploid lung fibroblasts after short term (2 h) serum-free exposure to recombinant cytokines. Both cytokines up-regulated these genes 1.5- to 3.6-fold. These cytokines have the potential to influence the remodeling and fibrosis observed in the lower respiratory tract in IPF and asbestosis.

Enhanced IL-1 beta and tumor necrosis factor-alpha release and messenger RNA expression in macrophages from idiopathic pulmonary fibrosis or after asbestos exposure

Idiopathic pulmonary fibrosis (IPF) and asbestosis are fibrotic interstitial lung diseases characterized by alveolar wall fibrosis with accumulation of extracellular matrix, interstitial remodeling, and increased numbers of activated alveolar macrophages. Animal models and in vitro studies have shown that macrophage cytokines, namely IL-1 beta and TNF-alpha, play significant roles in the development of fibrosis. We found significant increases for TNF-alpha release in both diseases (p &lt; 0.01) and a significant increase for IL-1 beta release in asbestosis compared to normal controls (p &lt; 0.01). Also, the mRNA expression of these cytokines was increased in alveolar macrophages from patients with IPF or asbestosis compared with normals. The level of TNF-alpha release in macrophage supernatants correlated with the number of neutrophils per milliliter bronchoalveolar lavage fluid returned. Chrysotile, crocidolite, amosite asbestos, and silica stimulated IL-1 beta and TNF-alpha release and up-regulated their respective mRNA in macrophages or monocytes. To evaluate the role of IL-1 beta and TNF-alpha in the accumulation of extracellular matrix, we studied collagen types I and III and fibronectin gene expression in human diploid lung fibroblasts after short term (2 h) serum-free exposure to recombinant cytokines. Both cytokines up-regulated these genes 1.5- to 3.6-fold. These cytokines have the potential to influence the remodeling and fibrosis observed in the lower respiratory tract in IPF and asbestosis.

Intraoperative high-dose rate interstitial irradiation of hepatic metastases from colorectal carcinoma. Results of a phase I-II trial

BACKGROUND

Resection of liver metastases from colorectal carcinoma can be curative. Unresectable but liver-confined metastases might be ablated by high-dose radiation with a similar curative result.

METHODS

At Georgetown University Hospital, 22 patients with unresectable hepatic metastases from colorectal carcinoma underwent 24 interstitial irradiation procedures at laparotomy in a Phase I-II study. A single dose was administered with a high-dose rate iridium-192 afterloader. Dose to the tumor periphery was 20 Gy, 25 Gy, and 30 Gy in 13, 9, and 2 procedures, respectively.

RESULTS

No acute or chronic radiation toxicity has occurred at a median follow-up of 11 months. Median actuarial local control at irradiated sites was 8 months, with 26% actuarial local control at 26 months by computed tomography (CT) or magnetic resonance imaging (MRI) scanning. In the two patients undergoing two procedures each, a second biopsy of previously irradiated areas demonstrated tumor eradication.

CONCLUSIONS

This innovative, radical approach to unresectable colorectal hepatic metastases proved safe. Additional study is needed to determine whether interstitial irradiation is as effective as surgical resection, or whether it alters the natural history of the disease or longevity.

Protection of a rat tracheal epithelial cell line from paraquat toxicity by inhibition of glucose-6-phosphate dehydrogenase

Transformed rat tracheal epithelial cells (U2) were found to be 3.6-fold more sensitive than lung fibroblasts (RLF) to paraquat. Although the toxic effects of paraquat are associated with the generation of very active superoxides, U2 cells contained higher levels of superoxide dismutase and catalase than RLF cells. On the other hand, the specific activities of both NADPH-cytochrome c reductase and glucose-6-phosphate dehydrogenase (G6DP) were 3- to 4-fold higher in U2 cells than in RLF cells. Treatment with dehydroepiandrosterone (DHEA) and epiandrosterone (EPI), G6PD inhibitors, significantly decreased the intracellular NADPH and protected U2 cells from paraquat toxicity. Since DHEA and EPI treatment did not affect the uptake of paraquat, our results suggest that paraquat sensitivity may depend on the redox cycling-associated activities of paraquat.

Evidence for biosynthesis of plasmenylcholine from plasmenylethanolamine in HL-60 cells

Both [3H]plasmenylethanolamine and [3H]plasmenylcholine were produced from substrates of [3H]alk-1-enylglycerol and [3H]alk-1-enyllysoglycerophosphoethanolamine by intact HL-60 cells. Molecular species analysis of the [3H]plasmenylcholine and [3H]plasmenylethanolamine formed indicated the major portion of plasmenylcholine originates from plasmenylethanolamine by a series of reactions catalyzed by phospholipase A2, lysophospholipase D, acyltransferase, phosphohydrolase, and cholinephosphotransferase. However, a significant but much smaller portion of the plasmenylcholine appeared to be synthesized from plasmenylethanolamine via a direct base-exchange or a coupled phospholipase C/cholinephosphotransferase reaction.

Primary structure of three distinct isoabrins determined by cDNA sequencing. Conservation and significance

A family of toxic proteins, the isoabrins, which possess N-glycosylase activity toward eukaryotic 28 S r-RNA, may have potential use in cancer chemotherapy. By polymerase chain reaction techniques, cDNA clones of three isoabrins, carrying A and B-chain sequences, were isolated and their nucleotide sequences were determined. The isoabrins consist of an A-chain comprised of 250 of 251 amino acids, followed by a 10 amino acid linker and a B-chain of 267 amino acids. There is substantial conservation in the B-chain of the three isoabrins, with less than six amino acid substitutions, whereas as many as 46 amino acid substitutions occur in the A-chains. Based on the relationships between the biological activities and the putative amino acid sequences of the isoabrins, three isoabrins, abrin-a, -b and -d, could be identified and the potential epitope of immunological response of these isoabrins could be assigned.

Expression of P-glycoprotein and glutathione-S-transferase in recurrent lymphomas: the possible role of Epstein-Barr virus, immunophenotypes, and other predisposing factors

PURPOSE

We previously have reported the poor prognoses of recurrent peripheral T-cell lymphoma (PTCL) and Epstein-Barr virus (EBV)-associated PTCL (J Clin Oncol 7:725-731, 1989; Blood 77:799-808, 1991). To study the role that drug resistance plays in this scenario, we conducted a retrospective study of 23 adult patients.

PATIENTS AND METHODS

All patients had recurrent lymphoma tissue available for immunophenotyping and screening for the existence of EBV DNA in tumor cells by Southern blot analysis and in situ hybridization. Expression of a multidrug resistance P-glycoprotein ([P-gp]mdr-1) and a glutathione redox cycle-related glutathione-S-transferase pi (GST-pi) was determined by an immunohistochemistry method.

RESULTS

Expression of mdr-1 or GST-pi was found in 11 (48%) and 12 (52%) cases, respectively. Most (11 of 12) of the GST-pi expression occurred simultaneously with mdr-1. Prechemotherapy tumor tissues were available in 11 cases; only two (18.2%) of these cases expressed mdr-1. Four (36%) of 11 cases that expressed mdr-1 (mdr-1(+)) and nine (90%) of 10 cases that did not express mdr-1 (mdr-1(-)) responded to second-line chemotherapy (P < .05). The survival-after-recurrence (SAR) curves significantly favored mdr-1(-) recurrent lymphoma (P < .05). The mdr-1 expression was further correlated with the immunophenotype and EBV association. All six cases of EBV-associated lymphoma (PTCL, five cases; Hodgkin's disease, one case) had significant simultaneous expression of mdr-1 and GST-pi in their recurrent tumor tissues.

CONCLUSION

(1) mdr-1 expression is a significant prognostic factor in recurrent lymphomas; (2) high expression of mdr-1 is observed in recurrent EBV-associated PTCL; and (3) GST-pi usually expresses simultaneously with mdr-1 in recurrent lymphomas. The role of EBV in the development of mdr-1 and the biologic significance of the simultaneous expression of mdr-1 and GST-pi in recurrent lymphomas are well worth further exploration.

Glutathione S-transferase pi in an arsenic-resistant Chinese hamster ovary cell line

A glutathione S-transferase (GST) was purified from an arsenic-resistant Chinese hamster ovary cell line, SA7. The SA7 GST was shown to catalyse the conjugation of glutathione and ethacrynic acid, a specific substrate for Pi class GST. Its N-terminal amino-acid sequence has 80% identical residues to that of rat GST P and human GST pi. Thus, the GST purified from SA7 cells belongs to the Pi family. Treatment with Cibacron Blue or ethacrynic acid, which are GST inhibitors, significantly decreased the resistance of SA7 cells to sodium arsenite. On the other hand, pretreatment of SA7N cells, a partial revertant of SA7 cells, with sublethal doses of sodium arsenite, cadmium acetate or zinc sulphate resulted in re-elevation of GST activities and the cells regained the arsenic resistance. The regained arsenic resistance was well correlated with the levels of GST pi which were induced dose-dependently by zinc sulphate. Heat-shock treatment (45 degrees C for 10 min) did not increase GST pi expression or arsenic resistance of SA7N cells. The results indicate that GST pi is possibly involved in the mechanism of arsenic detoxification.

Molecular epidemiology of endemic ciprofloxacin-susceptible and -resistant Enterobacteriaceae

OBJECTIVES

To elucidate the epidemiology of widespread ciprofloxacin resistance in our Veterans Affairs medical center using whole cell DNA analysis.

DESIGN

In vitro study of ciprofloxacin resistant and susceptible Enterobacteriaceae isolated during the course of a clinical epidemiologic study of quinolone resistance.

SETTING

Veterans Affairs Medical Center with acute care and long-term care divisions.

RESULTS

We examined 40 ciprofloxacin-resistant strains of Serratia marcescens, Proteus mirabilis, and Providencia stuartii using restriction endonuclease analysis of whole cell DNA and compared them with concomitantly isolated ciprofloxacin sensitive strains. We sought to determine whether resistant strains were identical to susceptible strains, indicating in vivo emergence of resistant strains from susceptible strains, and whether resistant strains were shared among patients. All 26 ciprofloxacin-resistant S marcescens isolates shared a single ecoRI restriction pattern. Multiple patterns were seen in the ciprofloxacin-susceptible S marcescens isolates; however, several isolates had a pattern matching that of the resistant isolates. Similar results were seen among the P mirabilis isolates. Three different ecoRI patterns were found among the ciprofloxacin-resistant P stuartii isolates; none matched those found among the susceptible isolates. The frequency of spontaneous emergence of ciprofloxacin resistance in susceptible S marcescens strains with restriction pattern matching that of the resistant strains was significantly higher than that of nonmatching strains.

CONCLUSIONS

Ciprofloxacin-resistant strains of Enterobacteriaceae became widespread within a short period of time. Resistant strains of S marcescens and P mirabilis arose from endemic susceptible strains. The resistant strain of S marcescens appeared to arise from a susceptible strain with a relatively high frequency of spontaneous ciprofloxacin resistance.

Mutational specificity of chromium(VI) compounds in the hprt locus of Chinese hamster ovary-K1 cells

Chromium(VI) compounds exert their genotoxicity and mutagenicity by complex metabolic reducing pathways that generate a variety of reactive forms of chromium and free radicals. To investigate the molecular nature of chromium-induced mutations, we characterized the entire coding region of the hypoxanthine (guanine) phosphoribosyltransferase (hprt) gene of 27 independent mutants derived from chromium(VI) oxide (CrO3)-treated Chinese hamster ovary-K1 cells, by direct sequencing of PCR-amplified cDNA. Among these mutants, 10 consisted of single base substitutions, five contained two base substitutions, one had four base substitutions, six were splicing mutations, and five exhibited single base pair insertions or deletions. All of the base substitutions and most of the frameshift mutations observed were located at A/T-rich sequences. More than 90% of the base substitutions (22/24) occurred in A.T base pairs. Among them, T-->A and T-->G transversions (18/22) predominated. The mutational hotspots for single and double base substitutions were the 3' thymidine of 5'PuT and thymidines of 5'ATTT sequences respectively. This mutational specificity was also observed in CHO-K1 cells treated with two other chromium(VI) compounds, namely K2Cr2O7 and PbCrO4. Strand bias was noticed in chromium mutagenicity, since 77% of T base substitutions occurred on the non-transcribed strand. This highly sequence-specific mutation spectrum suggests that a particular form of chromium may directly interact with DNA at these hotspot sequences.

Displacement of BrdUrd-induced YY1 by serum response factor activates skeletal alpha-actin transcription in embryonic myoblasts

Muscle-restricted transcription of the skeletal alpha-actin gene is controlled in part by a positive regulator, serum response factor (SRF), and a negative regulator, F-ACT1, which bind competitively to the most proximal serum response element (SRE1). We show here that F-ACT1 is identical to a transcription factor recently cloned and described as YY1, NF-E1, delta, or UCRBP. We found that although the DNA-binding activity of SRF accumulates during myogenesis, that of YY1 diminishes simultaneously. Myoblasts rendered incapable of differentiation by BrdUrd treatment exhibited the highest level of YY1 and the lowest level of SRF activities. Transfected SRF could directly transactivate the skeletal alpha-actin promoter by overcoming the inhibitory effect of BrdUrd-induced YY1. The transactivation depends on intact SRE DNA elements and requires the DNA-binding/dimerization domain of SRF as well as its C-terminal half rich in serines and threonines. Since the functions of YY1 and SRF appear to be developmentally regulated, the convergence of their binding sites upon the SRE constitutes an integrated mechanism whereby temporal and spatial muscle gene expression may be accomplished.

A novel CoA-independent transacetylase produces the ethanolamine plasmalogen and acyl analogs of platelet-activating factor (PAF) with PAF as the acetate donor in HL-60 cells

In this study, we demonstrate the presence of a unique membrane-associated transacetylase that transfers the acetate group from platelet-activating factor (PAF) to lysoplasmalogen (in the presence of EDTA and sodium acetate) with the formation of 1-alk-1-enyl-2-acetyl-sn-glycero-3-phosphoethanolamine (alk-1-enylacetyl-GPE). The identity of alk-1-enylacetyl-GPE was confirmed by acid hydrolysis, phospholipases A2 or C treatment and derivatization by fluorodinitrobenzene. The transacetylase has no requirement for Ca2+, Mg2+, or CoA and a broad pH optimum (7.0-8.0) with Km values of 12.0 microM for PAF and 106.4 microM for lysoplasmalogens. The enzyme activity from the isolated membrane fraction is not changed when whole cells are supplemented with 20:4, induced to differentiate into granulocytes, or treated with ionophore A23187. Radyllyso-sn-glycero-3-phosphocholine (GPC), radyllyso-GPE, acyllyso-sn-glycero-3-phosphoserine (GPS), acyllyso-sn-glycero-3-phosphoinositol (GPI), alkyllyso-sn-glycero-3-phosphate (GP), acyllyso-GP, or cis-9-octadecen-1-ol can also serve as acetate acceptors, whereas alkylglycerol, acylglycerol, or cholesterol are inactive. Differences in substrate acceptor specificity, sensitivity toward phenylmethylsulfonyl fluoride, and response to temperature suggest that the CoA-independent transacetylase and the CoA-independent transacylase that transfers long-chain acyl moieties are two separate enzymes. With intact differentiated HL-60 cells, [3H]acetate from [3H]PAF can be incorporated into alk-1-enylacetyl-GPE in the presence of ionophore A23187, but not in its absence. Moreover, phospholipase A2 inhibitors (p-bromophenacyl bromide and mepacrine) block the transacetylation process in whole cell system. These results indicate the production of alk-1-enyllyso-GPE is a rate-limiting factor for the subsequent transacetylation step during cell activation. We conclude that the transacetylase may participate in the biosynthesis of ethanolamine plasmalogen and acyl analogs of PAF, in vivo, fine-tuning of PAF biological responses, and cross-talk between de novo and remodeling pathways of PAF biosynthesis.

Legionella pneumophila in residential water supplies: environmental surveillance with clinical assessment for Legionnaires' disease

Although cases of community-acquired Legionnaires' disease have been epidemiologically linked to residential water supplies, the risk of acquiring Legionnaires' disease from exposure to Legionella pneumophila in residential water systems is uncertain. The residential water supplies of 218 members of the American Legion in six different geographical areas in Pittsburgh were cultured for L. pneumophila. Residents of the homes provided a recent medical history and a blood sample for detection of antibodies to legionella. A urine sample for legionella urinary antigen testing was also requested from individuals residing in legionella-positive homes and individuals with a positive antibody test. Six percent (14/218) of the homes yielded L. pneumophila (range within six areas 0-22%). Lower hot water tank temperature was significantly associated with legionella positivity (P less than 0.01). Analysis of water samples for mineral content showed no association between legionella positivity and concentrations of calcium and magnesium. Water samples from the area where 22% of the homes surveyed were positive for legionella had a higher iron content than water samples from the other areas tested. None of the individuals residing in legionella-positive homes showed elevated antibody titres to legionella or the presence of legionella antigen in urine. For the immunocompetent hosts, the risk of contracting Legionnaires' disease from exposure to contaminated household water supplies in the Pittsburgh area appears to be low.

Treatment of cerebellar infarction by decompressive suboccipital craniectomy

BACKGROUND AND PURPOSE

We present an anecdotal series of 11 patients without past history of stroke with progressive neurological deterioration while on medical therapy for large cerebellar infarctions. Clinical signs of brain stem compression developed in these patients. Computerized tomography of the head confirmed mass effect from brain edema. It was the clinical judgment of the neurologists and neurosurgeons that each of these 11 patients would expire without surgical intervention.

METHODS

All 11 patients (seven men, four women; mean age, 54 years) were treated with suboccipital craniectomy for decompression and temporary ventriculostomy for cerebrospinal fluid pressure monitoring and drainage.

RESULTS

Seven patients demonstrated neurological improvement on the first postoperative day. Two patients returned to their previous jobs 3 months after surgery. The Barthel Index indicated that six individuals were functioning with minimal assistance within a follow-up period of 16-60 months. The remaining three were functionally dependent. No mortality was noted in this series.

CONCLUSIONS

These results suggest that decompressive suboccipital craniectomy may be an effective, lifesaving procedure for malignant cerebellar edema after a large infarction.

Treatment of symptomatic syringomyelia with ventriculoperitoneal shunt: report of a case

We report on a 43-year-old female who, for 27 years, had thoracic scoliosis with curve convexity to the left side. She complained of rapid progression of the central cord syndrome in the past two years. Magnetic resonance imaging (MRI) demonstrated a syringomyelia with a direct connection between the fourth ventricle and the syrinx. The patient underwent a ventriculoperitoneal shunt and showed rapid neurologic improvement. A follow-up MRI showed dramatic shrinkage of the syrinx.

Using proteases to avoid false identification of DNA-protein complexes in gel shift assays

Gel mobility shift assays using crude nuclear extracts may result in the formation of multiple DNA-protein complexes reflected by their discrete gel mobilities. Identification of the multiple complexes can sometimes be complicated by the presence of protease activities in the extract as demonstrated here. We describe a simple protease-mediated partial digestion method that can be coupled with the gel shift assay to overcome the problem. The combined approach enables us to identify gel complexes that arise from protein degradation and therefore is suitable for analyzing those DNA-binding proteins exhibiting prominent protease sensitivity. The method should prove particularly informative in the search for tissue-specific complexes when crude extracts from different sources are compared by the gel shift assay.

Differential detection of multiple DNA-binding complexes using dissimilar polyanion competitors

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