Expression patterns of the immune checkpoint ligand CD276 in urothelial carcinoma

BACKGROUND

CD276 is an immune checkpoint molecule. Elevated CD276 expression by urothelial carcinoma is associated with poor prognosis, but little is known about its expression across different tumor stages. We therefore investigated CD276 expression in bladder cancer (BC) cells and in tissue samples of BC stages from pT2 to pT4.

METHODS

CD276 expression was explored in 4 urothelial cancer cell lines and 4 primary normal urothelial cell populations by quantitative RT-PCR, Western blot and flow cytometry. CD276 was investigated in bladder tumors from 98 patients by immunohistochemistry using a score (0-300) incorporating both, staining intensity and area of CD276 staining. Normal appearing urothelium in the bladder of the same patients served as controls.

RESULTS

The urothelial carcinoma cell lines expressed significantly higher levels of CD276 on transcript (p < 0.006), total protein levels (p < 0.005), and on the cell surface (p < 0.02) when compared to normal urothelial cells. In pT2-T4 tumor tissue samples, CD276 was overexpressed (median score 185) when compared to corresponding healthy tissues from the same patients (median score 50; p < 0.001). No significant differences in CD276 expression were recorded in late, locally advanced ≥ pT3a tumors (median score 185) versus organ-confined < pT3a tumors (median score 190), but it was significantly lower in the normal urothelial tissue associated with ≥ pT3a tumors (median score 40) versus < pT3a tumors (median score 80; p < 0.05).

CONCLUSION

CD276 expression is significantly elevated in urothelial carcinoma cells in all stages but varies between individuals considerably. Reduced CD276 expression in normal urothelial cells may imply that these cells would be protected from CD276-mediated immuno therapies.

Sugar Accumulation in Leaves of Arabidopsis sweet11/sweet12 Double Mutants Enhances Priming of the Salicylic Acid-Mediated Defense Response

In compatible interactions, biotrophic microbial phytopathogens rely on the supply of assimilates by the colonized host tissue. It has been found in rice that phloem localized SWEET sucrose transporters can be reprogrammed by bacterial effectors to establish compatibility. We observed that sweet11/sweet12 double mutants, but not single mutants, exhibited increased resistance toward the fungal hemibiotroph Colletotrichum higginsianum (Ch), both in the biotrophic and the necrotrophic colonization phase. We therefore investigated if the phloem localized transporters AtSWEET11 and AtSWEET12 represent additive susceptibility factors in the interaction of Arabidopsis with Ch. AtSWEET12-YFP fusion protein driven by the endogenous promoter strongly accumulated at Ch infection sites and in the vasculature upon challenge with Ch. However, susceptibility of sweet12 single mutants to Ch was comparable to wild type, indicating that the accumulation of AtSWEET12 at Ch infection sites does not play a major role for compatibility. AtSWEET12-YFP reporter protein was not detectable at the plant-pathogen interface, suggesting that AtSWEET12 is not targeted by Ch effectors. AtSWEET11-YFP accumulation in pAtSWEET11:AtSWEET11-YFP plants were similar in Ch infected and mock control leaves. A close inspection of major carbohydrate metabolism in non-infected control plants revealed that soluble sugar and starch content were substantially elevated in sweet11/sweet12 double mutants during the entire diurnal cycle, that diurnal soluble sugar turnover was increased more than twofold in sweet11/sweet12, and that accumulation of free hexoses and sucrose was strongly expedited in double mutant leaves compared to wild type and both single mutants during the course of Ch infection. After 2 days of treatment, free and conjugated SA levels were significantly increased in infected and mock control leaves of sweet11/sweet12 relative to all other genotypes, respectively. Induced genes in mock treated sweet11/sweet12 leaves were highly significantly enriched for several GO terms associated with SA signaling and response compared to mock treated wild-type leaves, indicating sugar-mediated priming of the SA pathway in the double mutant. Infection assays with salicylic acid deficient sweet11/sweet12/sid2 triple mutants demonstrated that reduced susceptibility observed in sweet11/sweet12 was entirely dependent on the SA pathway. We suggest a model how defects in phloem loading of sucrose can influence SA priming and hence, compatibility.

A Genetic Screen for Pathogenicity Genes in the Hemibiotrophic Fungus Colletotrichum higginsianum Identifies the Plasma Membrane Proton Pump Pma2 Required for Host Penetration

We used insertional mutagenesis by Agrobacterium tumefaciens mediated transformation (ATMT) to isolate pathogenicity mutants of Colletotrichum higginsianum. From a collection of 7200 insertion mutants we isolated 75 mutants with reduced symptoms. 19 of these were affected in host penetration, while 17 were affected in later stages of infection, like switching to necrotrophic growth. For 16 mutants the location of T-DNA insertions could be identified by PCR. A potential plasma membrane H⁺-ATPase Pma2 was targeted in five independent insertion mutants. We genetically inactivated the Ku80 component of the non-homologous end-joining pathway in C. higginsianum to establish an efficient gene knockout protocol. Chpma2 deletion mutants generated by homologous recombination in the ΔChku80 background form fully melanized appressoria but entirely fail to penetrate the host tissue and are non-pathogenic. The ChPMA2 gene is induced upon appressoria formation and infection of A. thaliana. Pma2 activity is not important for vegetative growth of saprophytically growing mycelium, since the mutant shows no growth penalty under these conditions. Colletotrichum higginsianum codes for a closely related gene (ChPMA1), which is highly expressed under most growth conditions. ChPMA1 is more similar to the homologous yeast genes for plasma membrane pumps. We propose that expression of a specific proton pump early during infection may be common to many appressoria forming fungal pathogens as we found ChPMA2 orthologs in several plant pathogenic fungi.

Gene expression profiling in skeletal muscle of Zucker diabetic fatty rats: implications for a role of stearoyl-CoA desaturase 1 in insulin resistance

AIMS/HYPOTHESIS

Insulin resistance in skeletal muscle is a hallmark of type 2 diabetes. Therefore, we sought to identify and validate genes involved in the development of insulin resistance in skeletal muscle.

MATERIALS

Differentially regulated genes in skeletal muscle of male obese insulin-resistant, and lean insulin-sensitive Zucker diabetic fatty (ZDF) rats were determined using Affymetrix microarrays. Based on these data, various aspects of glucose disposal, insulin signalling and fatty acid composition were analysed in a muscle cell line overexpressing stearoyl-CoA desaturase 1 (SCD1).

RESULTS

Gene expression profiling in insulin-resistant skeletal muscle revealed the most pronounced changes in gene expression for genes involved in lipid metabolism. Among these, Scd1 showed increased expression in insulin-resistant animals, correlating with increased amounts of palmitoleoyl-CoA. This was further investigated in a muscle cell line that overexpressed SCD1 and accumulated lipids, revealing impairments of glucose uptake and of different steps of the insulin signalling cascade. We also observed differential effects of high-glucose and fatty acid treatment on glucose uptake and long-chain fatty acyl-CoA profiles, and in particular an accumulation of palmitoleoyl-CoA in cells overexpressing SCD1.

CONCLUSIONS/INTERPRETATION

Insulin-resistant skeletal muscle of ZDF rats is characterised by a specific gene expression profile with increased levels of Scd1. An insulin-resistant phenotype similar to that obtained by treatment with palmitate and high glucose can be induced in vitro by overexpression of SCD1 in muscle cells. This supports the hypothesis that elevated SCD1 expression is a possible cause of insulin resistance and type 2 diabetes.

Metabisulphite-induced occupational asthma in a radiographer

There is epidemiological evidence for an increased prevalence of occupational asthma among radiographers. However, the causes of darkroom disease are not yet defined. A 37-year-old female radiographer reported work-related asthma approximately 2 yrs after starting work in a local hospital. She was atopic and showed bronchial hyperresponsiveness to methacholine. Occupational-type exposure with a fixing agent, but not with a developer, produced an immediate-type asthmatic reaction. As the fixing agent contained sodium metabisulphite (SMBS), a substance known to cause asthma, bronchial challenges with SMBS were performed in the patient and nine asthmatic controls. The patient showed a positive bronchial immediate reaction on 2 separate days after inhalation of 48 and 96 microg SMBS, and one control also showed a significant fall in forced expiratory volume in one second after inhalation of 12 microg SMBS. The positive reaction in the control subject argues for a greater susceptibility of both persons to SMBS or its reaction product sulphur dioxide, rather than for a new occupational allergen. It is concluded that sodium metabisulphite exposure should be recognised as a cause of darkroom asthma.

Differential hepatic gene expression in a polygenic mouse model with insulin resistance and hyperglycemia: evidence for a combined transcriptional dysregulation of gluconeogenesis and fatty acid synthesis

New Zealand obese (NZO) mice exhibit severe insulin resistance of hepatic glucose metabolism. In order to define its biochemical basis, we studied the differential expression of genes involved in hepatic glucose and lipid metabolism by microarray analysis. NZOxF1 (SJLxNZO) backcross mice were generated in order to obtain populations with heterogeneous metabolism but comparable genetic background. In these backcross mice, groups of controls (normoglycemic/normoinsulinemic), insulin-resistant (normoglycemic/hyperinsulinemic) and diabetic (hyperglycemic/hypoinsulinemic) mice were identified. At 22 weeks, mRNA was isolated from liver, converted to cDNA, and used for screening of two types of cDNA arrays (high-density filter arrays and Affymetrix oligonucleotide microarrays). Differential gene expression was ascertained and assessed by Northern blotting. The data indicate that hyperinsulinemia in the NZO mouse is associated with: (i) increased mRNA levels of enzymes involved in lipid synthesis (fatty acid synthase, malic enzyme, stearoyl-CoA desaturase) or fatty acid oxidation (cytochrome P450 4A14, ketoacyl-CoA thiolase, acyl-CoA oxidase), (ii) induction of the key glycolytic enzyme pyruvate kinase, and (iii) increased mRNA levels of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase. These effects were enhanced by a high-fat diet. In conclusion, the pattern of gene expression in insulin-resistant NZO mice appears to reflect a dissociation of the effects of insulin on genes involved in glucose and lipid metabolism. The data are consistent with a hypothetical scenario in which an insulin-resistant hepatic glucose production produces hyperinsulinemia, and an enhanced insulin- and substrate-driven lipogenesis further aggravates the deleterious insulin resistance of glucose metabolism.

Changes in low molecular weight DNA fragmentation in white blood cells after diisocyanate exposure of workers

The pathogenesis of diisocyanate-induced asthma is still largely unknown. Recently, it has been shown that thiol-redox homeostasis of human airway epithelial cells may be altered after in vitro exposure to diisocyanates. In the present study, low molecular weight (LMW) DNA fragmentation patterns in white blood cells (WBCs) were assessed on 16 industrial workers with work-related asthma, before and after chamber challenges with one of three commonly used diisocyanates in concentrations up to 30 ppb. LMW-DNA fragmentation changes were evaluated after 15 h incubation of WBCs embedded in agarose plugs in lysis buffer with or without hydrogen peroxide (H2O2). Increased LMW-DNA fragmentation occurred in WBCs taken at 30 min or 19 h after the end of the chamber challenge in both subjects with positive and in 8 of 14 subjects with negative challenges. In contrast, no change in LMW-DNA fragmentation was seen in WBCs taken at the same time intervals from 11 non-exposed controls. There was no association between changes in DNA fragmentation patterns and possible confounding factors such as age, smoking status, atopy, medication, duration of occupational exposure and period since exposure cessation. These results indicate that diisocyanate exposure can induce DNA fragmentation. Similarities in the increased amounts of WBC LMW-DNA fragments following diisocyanate exposure with the DNA fragmentation after plugs lysis in buffer with H2O2 support the hypothesis that diisocyanates change the intracellular redox steady-state. Whether this effect plays any role in isocyanate-induced asthma has to be investigated in larger epidemiological studies.

[Airways and lung disease by metal working fluids]

Metal working fluids (MWF) are used in the manufacturing process to cool and lubricate machined parts. MWF contain the coolant, mostly water-oil emulsions with soluble semi-synthetic or synthetic oils, but also emulsifiers and additives. Reaction products and both bacterial and fungal contamination occur during use. In the present review we listed literature data of dose-effect-relationships with a focus on biological substances. Most studies describe obstructive airways disease due to irritant effects of MWF. Immunoglobulin E mediated airways disease or hypersensitivity pneumonitis have rarely been described. There is no doubt that MWF exert adverse effects on human airways, but there is few data concerning dose-effect relationships. The role of bacterial and fungal contamination or endotoxin exposure cannot be defined by the available information. However, there is some evidence that biological components in MWF may represent the most hazardous substances.

Carboxyl residues in the iron-sulfur protein are involved in the proton pumping activity of P. denitrificans bc(1) complex

A study is presented on chemical modification of the three subunit Paracoccus denitrificans bc(1) complex. N-(Ethoxycarbonyl)-2-ethoxy-1,2-dihydroquinoline (EEDQ) treatment caused a loss of the proton pumping activity of liposome-reconstituted bc(1) complex. A similar effect, which is referred to as the decoupling effect, resulted upon reaction of N,N'-dicyclohexylcarbodiimide (DCCD) with the complex. Direct measurement of the binding of EEDQ to the complex subunits, performed in the presence of the fluorescent hydrophobic nucleophile 4'-[(aminoacetamido)methyl]fluorescein (AMF), showed that the iron-sulfur protein (ISP) and cytochrome c(1) were labeled by EEDQ, whereas cytochrome b was not. Tryptic digestion and sequencing analysis of the fluorescent fragment of the ISP revealed this to consist of a segment with six acidic residues, among which the highly conserved aspartate 160 is present. Analogous experiments on DCCD binding showed that all the three subunits of the complex were labeled. However, DCCD concentration dependence of carboxyl residue modification in the individual subunits and of proton pumping activity showed that the decrease of the H(+)/e(-) ratio correlated only with the modification of the ISP. Tryptic digestion of labeled ISP and sequencing analysis of the fluorescent fragment gave results superimposable upon those obtained with EEDQ. Chymotryptic digestion and sequencing analysis of the single fluorescent fragment of cytochrome b showed that this fragment contained glutamate 174 and aspartate 187. We conclude that, in the P. denitrificans bc(1) complex, carboxyl residues in cytochrome b do not appear to be critically involved in the proton pump mechanism of the complex.

Transcriptional activation of TRADD mediates p53-independent radiation-induced apoptosis of glioma cells

Survival of patients with Glioblastoma Multiforme (GM), a highly malignant brain tumor, remains poor despite concerted efforts to improve therapy. The median survival of patients with GM has remained approximately 1 year regardless of the therapeutic approach. Since radiation therapy is the most effective adjuvant therapy for GM and nearly half of GM tumors harbor p53 mutations, we sought to identify genes that mediate p53-independent apoptosis of GM cells in response to ionizing radiation. Using broad-scale gene expression analysis we found that following radiation treatment, TRADD expression was induced in a uniquely radiosensitive GM cell line but not in radioresistant GM cell lines. TRADD over-expression killed GM cells and activated NF-kappa B. We found that blocking the TRADD-mediated pathway using a dominant-negative mutant of FADD (FADD-DN) enhanced radiation resistance of GM cells, as reflected in both susceptibility to apoptosis and clonogenic survival following irradiation. Conversely, stable expression of exogenous TRADD enhanced radiation-induced apoptosis of GM cell lines, reflecting the biological significance of TRADD regulation in p53-independent apoptosis. These findings generate interest in utilizing TRADD in gene therapy for GM tumors, particularly in light of its dual function of directly inducing rapid apoptosis and sensitizing GM cells to standard anti-neoplastic therapy.

Bacillus subtilis spore film dosimeters in personal dosimetry for occupational solar ultraviolet exposure

OBJECTIVE

Ultraviolet (UV) radiation is noted to be one of the most important risk factors for nonmelanoma and melanoma skin cancers. The recent development of a spore film test chamber containing spores of Bacillus subtilis resulted in a new method of UV measurement with a spectral sensitivity profile similar to erythema-weighted data calculated from spectroradiometric measurements.

METHODS

The practical application of dosimeters was tested on 11 persons for 43 days, under different conditions of UV exposure in five different geographical regions. Four professional lifeguards at a public swimming pool carried dosimeters attached to their shoulders or to their caps, for 11 days. Three mountain guides attached dosimeters laterally to their heads on 27 different occasions of mountaineering activity in different mountain regions. Four ski instructors carried lateral head dosimeters during eight days of skiing in the Alps.

RESULTS

The life guards received daily UV exposures ranging from 3.6 to 9.5 minimal erythema doses (MED) (mean 5.9, SD +/- 1.9). The mountain guides had personal daily UV exposures of from 4.4 to 17.1 MED (11.9 +/- 3.9) and ski instructors from 2.8 to 8.8 MED (6.1 +/- 1.8).

CONCLUSIONS

Bacillus subtilis spore film dosimeters can be applied effectively for personal solar UV measurements of occupationally exposed persons. such as lifeguards. mountain guides and ski instructors. UV levels in these occupations exceed international limits of exposure.

Aberrant eruption and its relationship to crowding: the need for early detection and management

A modular, fixed-functional method has been described using a new generation of appliances that are smaller, more comfortable and more patient friendly, while gaining the advantages of a combined fixed-functional and postural therapy. The case has been made for the middle mixed dentition as the optimal starting time. Crowding, overbite and molar rotation are managed simply with a combined use of flexible lip bumpers, bite plane and sequential primary tooth extraction. In conclusion, Phase I Postural Therapy will be shown to have the following advantages: more biologically and patient friendly more conducive to non-extraction more efficient and cost effective simple fabrication and reduced chair time reduced Phase II fixed appliance time, and completion at a younger age.

Mutational analysis of residues forming hydrogen bonds in the Rieske [2Fe-2S] cluster of the cytochrome bc1 complex in Paracoccus denitrificans

Two mutations (S157A and Y159F) in the Rieske iron-sulfur subunit of the ubihydroquinone-cytochrome c oxidoreductase from Paracoccus denitrificans have been characterized with respect to the protein and [2Fe-2S] cluster stability, the enzyme activity and the redox potential of the [2Fe-2S] cluster. In the structure of the water-soluble fragment of the Rieske iron-sulfur protein of the bovine heart mitochondrial bc1 complex, both residues (S163 and Y165 in the bovine sequence) form the following hydrogen bonds to sulfur atoms in the [2Fe-2S] cluster: Ser163 O gamma-S-1 and Tyr165 O eta-Cys139 S gamma [Iwata, S., Saynovits, M., Link, T. A. & Michel, H. (1996) Structure 4, 567-579]. They are conserved in all known Rieske iron-sulfur proteins from bc1 complexes including that from P. denitrificans. Both amino acid exchanges, introduced as separate point mutations on plasmids containing the fbc operon, lead to a fully assembled three-subunit complex in P. denitrificans, with a metal and heme content as well as subunit composition indistinguishable from the parental strain. The purified complexes show decreased turnover numbers and redox potentials of the Rieske cluster. Whereas the turnover number of the bc1 complex isolated from the parental strain was 145 s(-1), the turnover numbers for the mutants S157A and Y159F were 10 s(-1) and 52 s(-1), respectively, corresponding to 7% and 36% activity, respectively. The midpoint potential Em of the Rieske cluster at pH 6 and 5 degrees C was +360 mV for the bc1 complex from the parental strain; the values in the mutant complexes were +316 mV (Y159F) and +265 mV (S157A). Shifts of the g values in the electron paramagnetic resonance spectra indicate an altered electron distribution in the mutants compared to in the wild-type protein.

[Voice prostheses with sound-producing metal reed element--an experimental study and initial clinical results]

BACKGROUND

Following total laryngectomy the voice is produced by esophageal speech as well as with voice prostheses by vibrations of pharyngeal mucosal folds. This pharyngeal sound normally has a significantly lower fundamental frequency than the healthy voice (men about 120 Hz, women about 240 Hz, pharyngeal voice about 70 Hz), which is a handicap especially for female laryngectomy patients. In order to improve the postlaryngectomy voice, a new type of voice prostheses containing an integrated sound-producing metallic reed element was developed (ADEVA Company, Lübeck, Germany).

METHODS/PATIENTS

Thirty-five of these new sound-producing voice prostheses were tested in vitro for different prosthesis-specific physical parameters (pressure, flow, sound pressure, flow resistance, frequency range). In 15 voice prosthesis speakers, a sound-producing prosthesis was introduced during a routine outpatient visit. Besides measurement of the above mentioned physical parameters in patients with conventional and sound-producing prostheses, the resulting voice as also evaluated by means of a video recording.

RESULTS

In vitro all prostheses with the metallic reed element produced a clear sound. Flow resistance of the prostheses was slightly elevated by the reed element. Insertion of the prostheses was hindered by the reed element. Period of uninterrupted sound production was prolonged after insertion of a sound-producing prosthesis and patients could speak on a lower pressure level, but the sound of the reed element was permanently distinguishable only in 6 of 15 patients.

CONCLUSIONS

In principle a variation of the pharyngeal voice by means of a sound producing element, which is integrated into a voice prosthesis, is possible. The current design of the metallic reed element tested is not yet suitable for routine clinical use: 1. The reed element is too sensitive and is easily damaged during insertion, so the insertion device has to be improved. 2. The sound producing element is blocked by small amounts of tracheal secretions, so that this element should be replaceable separately without requiring removal of the silicone value (if possible by the patient himself). Prior to insertion of the sound producing voice prosthesis the maximum air flow through the shunt should be measured to determine if the patient can produce the necessary air flow for activation of the reed element. A further improvement for these special types of voice prostheses would be a sound producing element, which generates a variable frequency of sound. Limiting the patient to only one fundamental frequency creates a monotone, which does not sound naturally. Initial progress toward a sound-producing voice prostheses has been made. This should be followed by the necessary improvements in order to improve the feasibility of this design for routine clinical use.

Phase II study with cisplatin and paclitaxel in combination with weekly high-dose 24 h infusional 5-fluorouracil/leucovorin for first-line treatment of metastatic breast cancer

Results from our previous phase II study demonstrating high efficacy and low toxicity for a weekly schedule of 5-fluorouracil (5-FU)/leucovorin in intensively pretreated patients with metastatic breast cancer prompted addition of paclitaxel and cisplatin to this regimen for a phase II study of outpatient first-line treatment of metastatic breast cancer. (MBC). Twenty-eight patients with metastatic breast cancer have been evaluated. Pretreatment comprised adjuvant CTX in 24 out of 28 patients, but no prior CTX for MBC. Patients were treated with 5-FU 2 g/m2 (24 h infusion) plus leucovorin 500 mg/m2 (2 h infusion prior to 5-FU) weekly for 6 weeks (days 1, 8, 15, 22, 29 and 36); in addition, paclitaxel 175 mg/m2 (3 h infusion) was administered on days 0 and 21, and cisplatin 50 mg/m2 (1 h infusion) on days 1 and 22 prior to 5-FU/leucovorin, repeated every 50 days. All patients were treated as outpatients using Port-a-Cath systems and portable pumps. Aside from common total alopecia, neutropenia was common but only of short duration. No episodes of febrile neutropenia occurred. Non-hematologic toxicities (NCl CTC grade, percent of patients) consisted of mild to moderate diarrhea (2+3, 47%), mucositis (2, 14%), and nausea and vomiting (2+3, 60%). Out of 28 patients with bidimensionally measurable disease 25% (seven out of 28) achieved a CR, 57% (16 out of 28) achieved a PR, 11% (three out of 28) had a SD and 7% (two out of 28) had a PD. Overall RR was 82% (95% confidence interval 66-100%). Median remission duration was 8 months, median time to progression 9 months and median survival time 28 months with a median follow-up of 21 months. We conclude that the combination of paclitaxel, cisplatin and 5-FU/leucovorin is an effective non-anthracycline-containing regimen for the first-line treatment of MBC.

[Latex allergy: local hypersensitivity reaction cause by an esophageal catheter in compliance determination]

We report on two latex-allergic subjects who developed local hypersensitivity reactions after their lung compliance was measured by an oesophagus balloon catheter. Protein and allergen analyses of this catheter showed values of 85 and 9.8 micrograms per gram rubber. It is concluded that latex-allergic subjects should not undergo examinations with latex allergen-containing catheters. To our knowledge, this is the first report on allergic reactions caused by latex balloons of an oesophagus catheter.

Expression studies on the ba3 quinol oxidase from Paracoccus denitrificans. A bb3 variant is enzymatically inactive

Expression of the quinol oxidase from Paracoccus denitrificans has been examined using a polyclonal antibody directed against subunit II and a promoter probe vector carrying the promoter region of the qox operon. Under aerobic conditions nitrate and nitrite act as specific inducers of the expression. To obtain an enzymatically competent quinol oxidase complex, an intact ctaB gene is required, which constitutes part of the cta operon coding for the aa3 cytochrome c oxidase of P. denitrificans. Deletion of ctaB leads to a change in heme composition of the quinol oxidase with heme b replacing the high-spin heme a of the binuclear center, causing loss of electron transport activity.

Infusional 5-FU, folinic acid, paclitaxel, and cisplatin for metastatic breast cancer

Our phase II study results demonstrating high efficacy and low toxicity for a weekly schedule of high-dose, 24-hour infusional 5-fluorouracil(5-FU)/folinic acid (HD5-FU/FA) in intensively pretreated patients with metastatic breast cancer prompted addition of paclitaxel (Taxol) to the regimen, for a phase I/II study of outpatient second-line treatment of metastatic breast cancer. That study further prompted the addition of cisplatin (Platinol) to the regimen for first-line treatment. So far, 28 patients with metastatic breast cancer have been evaluated. Pretreatment comprised adjuvant chemotherapy in 24 of 28 patients, but no prior chemotherapy for metastatic disease. Patients were treated with HD5-FU 2 g/m2 (24-hour infusion) plus FA 500 mg/m2 (2-hour infusion prior to FU) weekly for 6 weeks (days 1, 8, 15, 22, 29, and 36); in addition, paclitaxel 175 mg/m2 (3-hour infusion) was administered on days 0 and 21 and cisplatin 50 mg/m2 (1-hour infusion) on days 1 and 22 prior to HD5-FU/FA, repeated every 50 days. Patients were treated as outpatients using Port-a-Cath systems and portable pumps. Neutropenia was common (67% World Health Organization grade 3) but mild to moderate in most patients and was of short duration. No hospitalizations were required because of febrile neutropenia, and no granulocyte colony-stimulating factor support was used. Aside from common total alopecia, nonhematologic toxicities consisted mainly of moderate myalgia, diarrhea, mucositis, and nausea and vomiting. Hand-foot syndrome and peripheral neuropathy were cumulative and occurred most commonly during the third treatment cycle, with mild-to-moderate expression. In 28 patients with bidimensionally measurable disease, 25% (7/28) attained a complete response, 57% (16/28) achieved partial response, 11% (3/28) had stable disease, and 7% (2/28) had disease progression. Overall response was 82% (95% confidence interval, 66% to 100%). Eight of 28 patients are still receiving treatment. It is concluded that the combination of paclitaxel/cisplatin with weekly HD5-FU/FA appears to be effective in the first-line treatment of metastatic breast cancer. Preliminary results must be confirmed by the final analysis of response duration, time to progression, and survival.

Detection of 8-hydroxydeoxyguanosine, a marker of oxidative DNA damage, in white blood cells of workers occupationally exposed to styrene

Styrene-7,8-oxide (SO), the major in vivo metabolite of styrene, is a genotoxic compound and a potential carcinogenic hazard to occupationally exposed workers. The aim of the present work was to investigate the ability of styrene exposure to induce formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in white blood cells (WBC) of boatbuilders occupationally exposed to styrene. The study of these adducts was conducted to see if styrene exposure can cause oxidative damage of DNA. The 8-OHdG/10(5) dG ratio from 17 styrene-exposed workers showed significant increases (mean +/- SD, 2.23 +/- 0.54, median 2.35, P < 0.001) in comparison to the controls (1.52 +/- 0.45, median 1.50). However, 11 out of 17 workers who were between the ages of 32 and 60 years and had been occupationally exposed to styrene for > 10 years showed higher 8-OHdG/10(5) dG ratios (2.31 +/- 0.62, median 2.37) in comparison to 6 workers with < 6 years of occupational styrene-exposure (2.11 +/- 0.36, median 2.05; P > 0.05, no significant difference between the two groups of workers). The studies presented here provide an indication that styrene exposure can result in oxidative DNA damage.

Weekly infusional 5-fluorouracil plus/minus other drugs for the treatment of advanced gastric cancer

Based on preclinical data and the promising results being achieved with infusional 5-FU in colorectal and breast cancer, we investigated a weekly schedule of a 24-hour infusion of 5-FU plus folinic acid (HD-FU/FA) in patients failing to first-line chemotherapy and HD-FU/FA plus cisplatin (C) or plus cisplatin/epidoxorubicin (C/E) in chemo-naive patients with advanced gastric cancer. In all three trials the results achieved with the tested chemotherapy regimens indicated high activity and good tolerability. All three protocols were administered as outpatient treatment. With HD-FU/FA and overall response rate of 24% and a median survival time of 5 months was observed in 17 patients refractory to or relapsing after first-line chemotherapy. HD-FU/FA/C induced an overall response rate of 66% and a median survival time of 13 months. Of note was the high activity of this regimen in patients with malignant ascites. HD-FU/FA/C/E also proved to be an interesting regimen similar active as HD-FU/FA/C but it was subjectively less well tolerated. In patients with locally advanced disease the response rate was 90% (10/11), and in patients with distant metastases 50% (8/16).

Phase I study with a weekly 1 h infusion of paclitaxel in heavily pretreated patients with metastatic breast and ovarian cancer

Paclitaxel has proven to be an active agent in the treatment of breast and ovarian cancer [Seidman AD, Ann Oncol 1994, 5 (Suppl. 6), 17-22], but the optimal dose and schedule remain undefined. We performed a phase I study with a weekly 1 h infusion of paclitaxel. After premedication, patients received a 1 h infusion of paclitaxel on days 1, 8, 15, 22, 29 and 36 (every 50 days) using the following dose levels: dose level 1 70 mg/m2, dose level 2 80 mg/m2, dose level 90 mg/m2, dose level 4 100 mg/m2, 20 patients (17 breast, 3 ovarian cancer) with anthracycline- or platinum-refractory disease entered this trial. No dose limiting toxicities occurred at dose levels 1-3. 2 of the 4 patients at dose level 4 had neutropenia WHO grade 4. At all dose levels responses could be observed. Maximal tolerable dose (MTD) was reached using dose level 4. Paclitaxel, given in a weekly 1 h infusion, is safe and shows mild toxicity in heavily pretreated breast and ovarian cancer patients. We recommend dose level 3 for phase II studies.

GTP-binding proteins in adrenocortical mitochondria

We have identified two GTP-binding proteins in mitochondria from bovine adrenal cortex (fasciculata). Sub-mitochondrial particles were fractionated into inner membrane, contact point and outer membrane vesicles on sucrose density gradients. These sub-mitochondrial fractions were identified by the presence of enzyme markers and electron microscopy. Photoaffinity labelling with [gamma-32P]GTP identified a 45 kDa GTP-binding protein in outer mitochondrial membranes and a 19 kDa protein in the contact points. The molecular weight of 45 kDa and requirement for Mg2+ ions raise the possibility that this protein is an alpha subunit of a heterotrimeric GTP-binding protein or a novel GTP-binding protein. The specificity of nucleotide binding, the requirement for low concentrations of Mg2+ (0.1 mM) and molecular weight of 19 kDa suggest that this protein is a typical member of the so-called small GTP-binding protein family. The location of 45 kDa in the outer membrane and that of 19 kDa in the contact points suggest roles for these proteins in the interaction with the extramitochondrial environment and in the regulation of mitochondrial membranes, respectively.

[Differential diagnosis of round opacities after lung transplantation]

Incidence, aetiology, diagnosis and treatment of round lesions in the lungs were analysed in 64 patients after lung transplantation (33 men, 31 women; mean age 45 [21-68] years; postoperative survival > 2 weeks). These lesions were found in 8 patients 1-10 months (median of 5.8 months) after the transplantation, singly in two, multiple in six. In six patients it was an incidental finding, further elucidated by computed tomography or fine-needle biopsy. The aetiology varied from B-cell "lymphoma" (posttransplant lymphoproliferative disorder-PTLD) in three patients, aspergilloma in two, and bacterial abscess in one. Two patients died of septicaemia (Aspergillus; Pseudomonas aeruginosa/Staphylococcus aureus), while four had a full remission. The solitary lesions disappeared without specific treatment in 2-3 weeks. If round lesions are noted after lung transplantation, rapid histological and microbiological diagnosis and aggressive treatment are necessary to combat an otherwise high death-rate. PTLD and infection (bacterial or mycotic) are the most frequent causes.

Styrene-7,8-oxide in blood of workers exposed to styrene

A field study was carried out on 13 workers exposed to styrene vapors at time-weighted average concentrations between 10 and 73 ppm. The reactive intermediate styrene-7,8-oxide was determined in blood samples using a direct gas chromatographic method. Styrene-7,8-oxide concentrations were in the range between 0.9 and 4.1 micrograms/l blood. Linear correlations were found between styrene-7,8-oxide in blood and styrene in ambient air and blood. For an exposure concentration of 20 ppm styrene (German MAK value) a steady-state level of about 1 microgram styrene-7,8-oxide/l blood was calculated.

The composition of the intracellular domains of the B cell antigen receptor complex studied from the cytoplasmic side of the membrane

Immunoglobulins of the classes M and D function as antigen receptors on B lymphocytes. They are linked to other proteins to form B cell antigen receptor (BCR) complexes which transduce the signal triggered by the binding of antigen. In order to study the components that interact with BCR complexes in the cell it is essential that they are accessible to biochemical studies. Therefore, we have developed a simple and rapid method that allows the purification and labelling of B lymphocyte plasma membranes. For this, B cells are attached to polyacrylamide beads. Upon disruption of the cells, bead-bound membranes are obtained which expose the cytoplasmic side into the medium. The membrane proteins can then be radioiodinated and eluted with detergents. The combination of the improved methods for the preparation of bead-attached membrane patches and radiolabelling of the proteins has allowed for the first time an investigation into the cytoplasmic side of the BCR complex. All the subunits that had been previously described could be detected in 2D autoradiographs. Furthermore, it could be shown that the protein Ig-beta, which is part of an Ig-associated heterodimer, is predominantly labelled at the extracellular domain. The second component, Ig-alpha, is labelled to a higher degree at its intracellular domain. In addition, further proteins could be detected exclusively at the cytoplasmic side of the membrane. Results from 2D autoradiographs show that they may form heterodimers. These proteins are candidates for the interaction of BCR complexes with further members of the signalling cascade, such as protein tyrosine kinases and/or G proteins.

Calcium/calmodulin induces phosphorylation of vimentin and myosin light chain and cell rounding in cultured adrenal cells

In previous reports on adrenal cells we have shown that calcium/calmodulin regulates cholesterol transport to mitochondria and induces phosphorylation of cytoskeleton homogenates. In this study, we have used bovine fasciculata cells permeabilized in situ to identify the phosphorylated proteins and to investigate the manner in which the cytoskeleton components may act together in any subsequent reorganization of the cell. The main cytoskeletal proteins namely vimentin, tubulin, actin, and the associated protein myosin light chain were identified on polyacrylamide gel electrophoresis by their molecular weights and by Western blotting using affinity-purified monoclonal antibodies. In permeabilized cells, calcium/calmodulin promoted phosphorylation of vimentin and myosin light chain within the first 10 min. When incubation time was extended in the presence of 1 mM non-radiolabeled ATP, cell contraction was seen after 15 min. Immunofluorescent microscopy showed that actin microfilaments and myosin light chain displayed a similar pattern of distribution which indicates the actomyosin. Electron microscopy revealed the actomyosin as a dense ring around the cell beneath the plasma membrane. Intermediate filaments (10 nm) were seen within this ring which gave rise to a mixed network in which microfilaments appeared to interconnect intermediate filaments. Immunogold electron microscopy revealed that the 10-nm filaments, found within the actomyosin ring, are vimentin intermediate filaments. It is proposed that calcium/calmodulin causes phosphorylation of the myosin light chain which triggers contraction, and this process involves the intermediate filament protein vimentin. The redistribution of the cytoskeleton and hence the cell rounding is due, in part to the interconnection between vimentin intermediate filaments and actin microfilaments.(ABSTRACT TRUNCATED AT 250 WORDS)

CD45-deficient RBL-2H3 cells. Cellular response to Fc epsilon R- and ionophore-induced stimulation

The CD45 protein is a transmembrane tyrosine phosphatase that is required for normal T and B cell receptor-mediated signaling. In order to study the function of this phosphatase in mast cells, we have isolated a CD45-deficient variant from the rat basophilic leukemia cell line (RBL-2H3), a tumor analog of mucosal mast cells. The secretory response as well as the inositol 1,4,5-triphosphate (InsP3) formation to Fc epsilon RI and ionophore stimuli were similar in the RBL-2H3 cell line and its derived CD45-deficient subpopulation. However, pretreatment with the phorbol ester TPA, which directly activates protein kinase C (PKC), caused a marked increase in mediator release and InsP3 production in the CD45-deficient variant compared to the parental RBL-2H3 cells. These findings suggest that CD45 might directly or indirectly modify the activity of PKC or the InsP3-dephosphorylating phosphatase.