Dexrazoxane cardioprotection in advanced breast cancer patients undergoing high-dose epirubicin treatment

PURPOSE

We performed a randomized trial to evaluate the cardioprotective effect of dexrazoxane (DEX) in advanced breast cancer patients (ABC) treated with high single-dose epirubicin (EPI). A secondary objective was to determine the role of radioimmunoscintigraphy (RIS) in the assessment of epirubicin cardiotoxicity.

PATIENTS AND METHODS

Ninety-five patients with ABC were treated with EPI 160 mg/m2 by i.v. bolus every 3 weeks with or without DEX, 1,000 mg/m2 i.v. Cardiac monitoring included multigated radionuclide (MUGA) scan with determination of resting left ventricular ejection fraction (LVEF), and RIS with 111-Indium antimyosin monoclonal antibodies.

RESULTS

The overall response rate was 69% in the EPI arm and 67% in the EPI + DEX arm; median time to response and median time to progression were identical in both arms, being 2 and 8 months, respectively. Median survival was 19 months versus 29 months (p 0.21), respectively. DEX did not appear to contribute to extracardiac EPI toxicity. Congestive heart failure occurred only in the EPI arm (2 instances). LVEF significantly decreased from baseline only in the EPI group. An abnormal tracer uptake at RIS was observed early in both arms, but the increase in heart to lung ratio was much more evident in the control group.

CONCLUSIONS

DEX significantly protects against the development of high dose epirubicin cardiotoxicity apparently without evidence of an adverse impact on antitumor activity and non cardiac toxicity. RIS is a very sensitive technique in detecting anthracycline cardiac damage, but its specificity is low and cannot be considered alone a primary test for guiding anthracycline treatment.

Conservative surgery and radiotherapy in early stage breast cancer: a comparison between tumourectomy and quadrantectomy

BACKGROUND AND PURPOSE

This study analyses and compares the results of local regional control, distant metastases and survival in two series of patients irradiated from 1986 to 1992 in our radiation oncology centre following quadrantectomy or tumourectomy for early stage breast cancer.

MATERIALS AND METHODS

The quadrantectomy group consisted of 152 women, 109 (72%) with T1 and 43 (28%) with T2 tumours. Axillary nodes in this group were positive in 51 (33%) patients. The tumourectomy group included 123 women, 71 (58%) with T1 and 52 (42%) with T2 tumours. Positive axillary nodes were found in 56 (46%) of these patients. All quadrantectomy and tumourectomy patients received a dose of 50 Gy in 5 weeks to the whole breast, followed by a 10-16 Gy electron boost. Node positive patients in the tumourectomy group also received 50 Gy to the axillary apex and supraclavicular region. In both surgical groups, node positive premenopausal and postmenopausal patients received adjuvant CMF or tamoxifen therapy, respectively.

RESULTS

After a median follow-up of 58 months, 89% of women in the tumourectomy group and 87% in the quadrantectomy group were alive and 80 and 73%, respectively, were free of disease. Breast and nodal failures were detected in 4.9 and 0.8% of cases, respectively, in the tumourectomy group, as compared to 5.9 and 3.3% of cases, respectively, in the quadrantectomy group. Distant relapses were observed in 16 and 18% of patients in the former and latter groups, respectively. Actuarial overall and disease-free survival was similar in the two series, with 5-year rates of 90 and 72%, respectively, in the tumourectomy group, and of 91 and 78%, respectively, in the quadrantectomy group. The differences in survival are not statistically different.

CONCLUSIONS

Our findings show that tumourectomy and quadrantectomy, followed by adequate radiotherapy, provide comparable results in terms of local-regional control and survival.

Randomized prospective clinical trial of high-dose epirubicin and dexrazoxane in patients with advanced breast cancer and soft tissue sarcomas

PURPOSE

We conducted a randomized trial to evaluate primarily the cardioprotective effect of dexrazoxane (DEX) in patients with advanced breast cancer and soft tissue sarcomas (STS) treated with high-dose epirubicin (EPI). We wished also to determine the value of radioimmunoscintigraphy (RIS) in the assessment of anthracycline cardiotoxicity.

PATIENTS AND METHODS

Patients with breast cancer (n = 95) or STS (n = 34) received EPI 160 mg/m2 by intravenous (I.V.) bolus every 3 weeks with or without DEX 1,000 mg/m2 I.V. Cardiac monitoring included multigated radionuclide (MUGA) scans with determination of resting left ventricular ejection fraction (LVEF), and RIS with indium 111 antimyosin monoclonal antibodies.

RESULTS

In either disease, antitumor response rates, time to progression, and survival did not significantly differ between the two arms. There was little difference in noncardiac toxicity for the two treatment groups. All methods of cardiac evaluation clearly documented the cardioprotective effect of DEX. Four patients developed congestive heart failure (CHF), all in the EPI arm. The decrease in LVEF from baseline was significantly greater in the control group. An abnormal antimyosin uptake was observed early in both arms and progressively increased during treatment. However, this increase was significantly higher in the EPI group (P = .004).

CONCLUSION

DEX significantly protects against the development of cardiotoxicity when high single doses of EPI are used. Apparently, there was no evidence of an adverse impact of DEX on antitumor activity. Although RIS is a sensitive technique in detecting anthracycline cardiac damage, its specificity is low and it cannot be considered a primary test for guiding anthracycline treatment.

Sterol utilization and metabolism by Heliothis zea

Heliothis zea (corn earworm), an insect that fails to synthesize sterols de novo, was reared on an artificial diet treated with 18 different sterol supplements. Larvae did not develop on a sterol-less medium. delta 5-Sterols with a hydrogen atom, a methylene group, an E- or Z-ethylidene group, or an alpha- or beta-ethyl group (cholesterol, ostreasterol, isofucosterol, fucosterol, sitosterol, and clionasterol, respectively) at position C-24, and delta 5-sterols doubly substituted in the side chain at C-24 with an alpha-ethyl group and at C-22 with a double bond (stigmasterol) supported normal larval growth to late-sixth instar (prepupal: maturity). The major sterol isolated from each of these sterol treatments was cholesterol, suggesting that H. zea operates a typical 24-dealkylation pathway. The sterol requirement of H. zea could not be met satisfactorily by derivatives of 3 beta-cholestanol with a 9 beta, 19-cyclopropyl group, gem dimethyl group at C-4, a delta 5,7-bond or delta 8-bond, or by side chain modified sterols that possessed a delta 25(27)-24 beta-ethyl group, delta 23(24)-24-methyl group or 24-ethyl group, or delta 24(25)-24-methyl or 24-ethyl group. The major sterol recovered from the larvae (albeit developmentally arrested larvae) treated with a nonutilizable sterol was the test compound. Sterol absorption was related to the degree of sterol utilization. The most effective sterols absorbed by the insect ranged from 27 to 66 micrograms per insect, whereas the least effective sterols absorbed by the insect ranged from 0.6 to 6 micrograms per insect. Competition experiments using different proportions of cholesterol and 24-dihydrolanosterol (from 9:1 to 1:9 mixtures) indicated that abnormal development of H. zea may be induced on less than a 1 to 1 mixture of utilizable (cholesterol) to nonutilizable (24-dihydrolanosterol) sterols. The results demonstrate new structural requirements for sterol utilization and metabolism by insects, particularly with respect to the position of double bonds in the side chain and functionalization in the nucleus. The novel sterol specificities observed in this study appear to be associated with the dual role of sterols as membrane inserts (nonmetabolic) and as precursors to the ecdysteroids (metabolic).

HLA class I and class II alleles and haplotypes in Mexican mestizos established from serological typing of 50 families

We describe new information on the frequency and association of class II antigens (HLA-DR and HLA-DQ) of the major histocompatibility complex (MHC) in Mexicans. The study includes HLA-B typing and its association with the HLA-DR antigens determined in 50 families, which included 100 individuals. This family study allowed the establishment of the precise composition of the 200 HLA haplotypes, which cannot be obtained from unrelated individuals. The predominant antigens in decreasing order of frequency were B35, B39, and B61 at the B locus; DR4, DR5, and DR8 at the DR locus; and DQ3 at the DQ locus. The most common HLA-B,HLA-DR haplotype (considering broad specificities) was B16,DR4, with a frequency of 8.0%. Five HLA-B,HLA-DR haplotypes showed significant delta values (observed vs. expected frequencies) after correcting for the number of comparisons. On the other hand, the most common HLA-DR,HLA-DQ haplotypes were DR4,DQ3 and DR5,DQ3 with a frequency higher than 10%. Ten of the 17 HLA-DR,HLA-DQ haplotypes had significant postcorrection delta values.

Clinical relevance of radionuclide angiography and antimyosin immunoscintigraphy for risk assessment in epirubicin cardiotoxicity

BACKGROUND

Cardiotoxicity is the major limiting factor in anthracycline chemotherapy of advanced neoplastic disease. Epirubicin shows a more favorable therapeutic index than does doxorubicin, but it is still cardiotoxic. Limited data regarding epirubicin cardiotoxicity are available, and suggested guidelines for doxorubicin with left ventricular ejection fraction (LVEF) measurement may not be empirically useful for epirubicin therapy. This study evaluates the diagnostic role of antimyosin immunoscintigraphy for early identification of patients at risk for late pump dysfunction from cardiotoxicity induced by high-dose administration of epirubicin up to high cumulative dosages.

METHODS AND RESULTS

Chemotherapy with epirubicin was administered to 36 patients with cancer at a dosing rate of 160 mg/m2 as a bolus injection every 21 days to a cumulative dosage of 960 mg/m2. Radionuclide angiography (LVEF) and antimyosin immunoscintigraphy with heart-lung ratio (HLR) measurements were performed before chemotherapy, at intermediate cumulative epirubicin dosages, at the end of treatment, and during the follow-up. LVEF decreased significantly at the end of the treatment and after therapy discontinuation. HLR values were significantly increased at intermediate epirubicin dosage levels and continued to increase to the end of the treatment but thereafter remained substantially unmodified for 3 to 6 months after therapy discontinuation. A value of HLR >1.85 at intermediate epirubicin dosage level showed a sensitivity of 95% and a specificity of 57% as a predictor of late LVEF impairment.

CONCLUSIONS

LVEF appears more useful at high cumulative dosages and during follow-up to monitor late pump dysfunction, whereas HLR may be effective during the early phase of the therapy in determining which patients are at risk for development of late cardiac dysfunction.

Altered expression of insulin-like growth factor II receptor in human pancreatic cancer

The insulin-like growth factor-II (IGF-II) receptor (IGF-IIR) is a single-chain transmembrane protein identical to the mannose-6-phosphate receptor. In the present study we examined IGF-IIR expression in normal and cancerous human pancreatic tissues. In the normal pancreas, moderately strong IGF-IIR immunoreactivity was present in the cytoplasm of islet cells, and mild cytoplasmic immunoreactivity was evident occasionally in ductal and acinar cells. Some ductal cells also exhibited nuclear IGF-IIR immunoreactivity. In the pancreatic cancers, regions of strong IGF-IIR immunoreactivity were present in the duct-like cancer cells within the tumor mass, often exhibiting nuclear localization. Expression of IGF-IIR mRNA in the cancer cells was confirmed by in situ hybridization. By comparison with normal pancreatic tissues, 7 of 12 pancreatic cancers exhibited a 5.6-fold increase in IGF-IIR mRNA levels, whereas in 3 cancers the IGF-IIR transcript was below the level of detection. Furthermore, all six tested cultured human pancreatic cancer cell lines expressed the IGF-IIR mRNA transcript. Our data indicate that IGF-IIR is overexpressed in a significant number of human pancreatic cancers, where it has a tendency to localize in the nucleus, and raise the possibility that IGF-IIR may contribute to the pathobiology of pancreatic cancer.

IL-13 induces CD34+ cells isolated from G-CSF mobilized blood to differentiate in vitro into potent antigen presenting cells

Dendritic cells (DCs), which are antigen presenting cells of potential use in human antitumor vaccination trials, are presently the subject of intense investigation. Many recent studies have reported the possibility of generating ex vivo large numbers of DCs with high antigen presenting capacity by the culture of bone marrow or blood progenitors. In this study, we examined the differentiation into DCs of CD34+ progenitors isolated from the G-CSF mobilized blood of 3 healthy donors and 5 patients with breast cancer and cultured in the presence of GM-CSF + IL-13. The characteristics of the cells were compared to those of cells obtained in the presence of GM-CSF + TNF alpha. By day 15, one third of the bulk cells cultured with IL-13 were CD1a+/CD14- and strongly expressed CD1c, CD40, CD80 and HLA-DR. In contrast, cells obtained with TNF alpha expressed CD1a on one in three cells but with a considerably lower fluorescence intensity than on IL-13-cultured cells and strongly expressed CD14 on more than 50% of cells. CD1a+/CD14- cells emerged in IL-13 cultures at day 5, while in TNF alpha cultures CD14+ cells appeared before CD1a+ cells. Cells grown in the presence of IL-13 had an increased capacity to present antigens to autologous lymphocytes and to stimulate allogeneic T-lymphocytes. This effect was greater than that of cells grown in the presence of TNF alpha. These cells should therefore have greater effector potential in any therapeutic applications in humans.

Bone marrow versus peripheral blood progenitor cells CD34 selection in patients with non-Hodgkin's lymphomas: different levels of tumor cell reduction. Implications for autografting

Human CD34+ selected cells are able to reconstitute hematopoiesis in patients receiving a myeloablative treatment. Although the role of reinfused tumor cells contaminating the grafts on the determination of postautograft relapses remains unclear, the major interest of CD34+ cell selection is to reduce the tumor contamination of the graft. This can be achieved if tumor cells do not express the CD34 antigen. We previously showed that this approach was effective with bone marrow (BM) collections in patients with non-Hodgkin's lymphoma (NHL). Because peripheral blood progenitor cells (PBPC) allow faster hematologic recovery than BM and are expected to contain less tumor contamination, we have compared the results of CD34+ cell selection in 35 BM and 16 PBPC from 48 patients with NHL. The PBPC were collected after a course of chemotherapy followed by granulocyte colony-stimulating factor (G-CSF) administration. The data showed that the final CD34+ cell purity achieved with PBPC was higher than with BM (medians, 70% v 50%; P = .02). The CD34+ cell recovery was also better for PBPC (medians, 42% v 24%; P = .001). Tumor contamination was assessed by detection of BCL2/JH rearrangement using polymerase chain reaction (PCR) in 38 of 48 patients (22 BM, 16 PBPC). In addition, immunoglobulin heavy chain gene (IgH) rearrangements were investigated using PCR with consensus IgH primers. At harvesting, 10 of 22 BM and two of 16 PBPC contained BCL2/JH+ cells, one of 22 BM and 14 of 16 PBPC contained abnormal IgH+ cells (one PBPC contained both BCL2/JH+ and abnormal IgH+ cells) at harvesting. However, because lymphoma tissue specimens from patients at diagnosis were not available, the malignant character of IgH rearrangements could not be confirmed by sequencing and probing with allele-specific nucleotides. After CD34+ cell selection, a reduction to below the level of detection of BCL2/JH+ cells of BM and PBPC was effective in seven of 12 informative selections. In contrast, a reduction to below the level of detection of abnormal IgH+ cells was effective in only three of 15 informative selections. However, the detection of cells with an abnormal IgH pattern in the context of chemotherapy plus G-CSF progenitor mobilization in patients with NHL and its correlation with actual tumor contamination needs further investigation.

Technetium-99m-MIBI scintigraphy in the assessment of neoadjuvant chemotherapy in breast carcinoma

Presurgical neoadjuvant chemotherapy (PSNC) is the treatment of choice for patients with locally advanced breast carcinoma (LABC). Accurate assessment of tumor response is important in planning subsequent treatments. Conventional response assessment by mammography and clinical evaluation is not fully reliable. This study evaluates the diagnostic yield of serial 99mTc-MIBI scintigraphy in the assessment of LABC response to PSNC.

METHODS

Twenty-nine patients affected by LABC underwent clinical, mammographic and 99mTc-MIBI scintigraphy before and after 3 cycles of FEC (500 mg/m2 5-fluorouracil, 50 mg/m2 epirubicin and 400 mg/m2 cyclophosphamide) on Days 1 and 8. Surgery was planned for 15 days after the third cycle of chemotherapy. Pathological status was obtained after surgery in all patients.

RESULTS

Sensitivities (i.e., true-positive ratios) for a correct prediction of tumor presence after PSNC were 65% for scintigraphy, 35% for clinical evaluation and 69% for mammography. Specificities (i.e., true-negative ratios) for a correct prediction of tumor absence after PSNC were 100% for scintigraphy, 67% for clinical evaluation and 33% for mammography. Technetium-99m-MIBI uptake in this series did not correlate with P-170 expression, proliferating cell nuclear antigen, Her-2/neu oncogene protein, antihuman endothelial cell CD31 antigen and estrogenic and progestinic receptor status.

CONCLUSION

Technetium-99m-MIBI scintigraphy is effective in monitoring the response to PSNC in LABC patients. Its diagnostic yield is clearly superior to clinical evaluation alone. Scintigraphy performs as does mammography in patients with negative response, but it is clearly superior in patients with positive response.

First report of recombination between the HLA-DR and HLA-DQ loci within a family

Although unusual associations of HLA-DR and HLA-DQ alleles seen in ancestral haplotypes have indicated that recombination between these genes occurred in the past, an actual crossover event between DR and DQ has never been shown within a family. In a study of families with Graves' disease we have identified an individual from a three generation family who inherited a maternal haplotype that is the result of a recombinational event between the HLA-DR and the HLA-DQ loci on her chromosomes. Family members were typed for HLA class I by the lymphocyte microcytotoxicity test and for HLA class II by polymerase chain reaction (PCR) with sequence-specific primers or with sequence-specific oligonucleotide probes after PCR. Based on linkage disequilibrium it is likely that the recombinant haplotype is present in the proband rather than his brother. This haplotype was subsequently inherited by one of the proband's sons. The data presented support the conclusion that the recombinant haplotype resulted from a crossover event between the mother's DRB1 and DQA1 genes. Thus, recombination between the HLA-DR and HLA-DQ genes has been demonstrated within this family; a recombination event not previously described.

Microheterogeneity of the oligosaccharides carried by the recombinant bovine lactoferrin expressed in Mamestra brassicae cells

The development of therapeutic glycoprotein production using the baculovirus expression system depends on the ability of insect cell lines to reproduce site specific mammalian-like N-glycans. A combination of 1H-NMR and mass spectrometry techniques (MALD-MS, ES-MS, and CID-MS-MS) allowed us to elucidate the N-linked oligosaccharides microheterogeneity on three different N-glycosylation sites, Asn233, Asn476, and Asn545, of a baculovirus-expressed recombinant bovine lactoferrin produced in Mamestra brassicae. Two families of N-glycan structures have been found: first, oligomannosidic glycans (Man[9-5]GlcNAc2) and secondly, short truncated partially fucosylated glycans (Man(3-2)[Fuc(0-1)]GlcNAc2). These results indicate that Mamestra brassicae cell line is not able to synthesize complex N-glycans, even if an alpha1,6-linked fucose residue is frequently present on the asparagine-bound N-acetylglucosamine residue of short truncated structures. Nevertheless, we have shown that Mamestra brassicae ensures the same N-glycosylation pattern as found on natural bovine lactoferrin showing the same distribution between complex and high-mannose type glycans on the different glycosylation sites. Sites which are naturally occupied by high-mannose glycans (Asn233 and Asn545) are substituted essentially by the same type of N-glycans in the recombinant counterpart, and the site Asn476,which carries sialylated complex type chains in the natural glycoprotein, is substituted by short, truncated, partially fucosylated chains in Mamestra brassicae-expressed bovine lactoferrin. These various results lead us to the conclusion that bovine lactoferrin is an interesting model to determine the potential of glycosylation of the baculovirus/insect cell expression systems.

Lymphocyte proliferative response and tissue distribution of methylmercury sulfide and chloride in exposed rats

The immunotoxic effects and tissue distribution of different forms of methylmercury compounds were studied in rats. Methylmercury sulfide or methylmercury chloride was fed to rats at concentrations of 5 or 500 microg/L in drinking water for 8 wk. T-cell lymphocyte proliferative response to phytohemagglutinin (PHA) and determination of tissue distribution of mercury by gas chromatography using electron capture were assayed. Four different forms of mercury compounds were employed: MeHgS-, (MeHg)2S, (MeHg)3S+, and MeHgCl. Results indicated that exposure to methylmercury significantly enhanced lymphocyte responsiveness in most of the exposed groups at the low concentration of 5 microg/L, with the highest proliferative response (fourfold increase) in the MeHgCl group. At 500 microg/L, a significant decrease in the lymphocyte proliferative response was observed in the (MeHg)3S+ and MeHgCl groups; conversely, the MeHgS(-)- and (MeHg)2S-exposed animals had a modest increase of the lymphocyte proliferative response. The largest concentrations of all four mercury forms were detected in the kidney and spleen. The levels of mercury found in kidney, spleen, liver, brain, and testis were lower in the MeHgCl group than in those exposed to (MeHg)2S and (MeHg)3S+. These data indicate that the organ distribution of mercury and immune alteration may vary according to the chemical structure of the compound. This observation may have important implications in humans potentially exposed to low levels of methylmercury present in the environment, since the immune system plays an important regulatory role in the host-defense mechanisms.

Evaluation of the deswelling period in dextran-containing medium after corneal organ culture

PURPOSE

To evaluate corneal structural modifications induced by the deswelling period in dextran-containing medium following organ culture.

METHODS

Twenty human corneas were organ-cultured for 2 weeks and subsequently incubated in Exosol deswelling medium (Opsia, Toulouse, France) for 1-4 days. Corneas were studied by means of light microscopy, morphometry, and transmission electron microscopy.

RESULTS

The deswelling period induced a statistically significant 8.4% endothelial cell loss and a 27.4% increase in the coefficient of variation. The endothelial layer remained intact. The basal epithelial cells displayed a flat appearance. Thin endothelial cells were observed in addition to dark vacuoles (the number of which increased with incubation time) with dense material and no mitochondrial swelling. Some basal epithelial cells and keratocytes were damaged on day 3 or 4.

CONCLUSIONS

Preservation injuries induced by 1 or 2 days of incubation in deswelling medium are moderate. Three or 4 days of incubation result in more severe dextran-induced injuries. Consequently, the deswelling period should not exceed 2 days.

Capillary electrophoresis for purity estimation and in-process testing of recombinant GB virus-C proteins

Protein purity estimation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) coupled with scanning densitometry is a critical component in the manufacture of recombinant proteins for commercial diagnostic assays. However, the procedure is time consuming and often difficult to reproduce because commercial dyes that are used for visualizing proteins do not bind in a stoichiometric fashion for all proteins. The present report describes the use of a rapid and dye-independent SDS polymer-filled capillary gel electrophoresis (CE-SDS) method to estimate protein purity. The CE-SDS method was used for in-process and final purity testing of GB virus-C (GBV-C) fusion proteins produced in E. coli, and was directly compared with the conventional SDS-PAGE method using purified Coomassie blue dye to reduce protein staining anomalies. The CE-SDS method may serve as an alternative or replacement method to the lengthy and tedious SDS-PAGE method. This study also demonstrates that the observed molecular weight of the fusion protein, determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), provides higher accuracy than values estimated by either CE-SDS or SDS-PAGE methods.

Identification of second malignancies on effusions and fine-needle aspirates using a panel of monoclonal antibodies

The longer survival of neoplastic patients achieved through improvements of therapeutic regimens has increased the relative risk of developing a second primary tumour (SPT). In this context, conventional cytopathology can define tumour histotype only in a small fraction of cases. In this study, we have evaluated whether selected combinations of monoclonal antibodies (MAbs) to tumour-associated antigens (TAAs) can increase the accuracy of conventional morphology in detecting second primary tumours (SPTs) in two particularly difficult areas of cytodiagnosis, namely that of effusions and pulmonary fine-needle aspirates (FNAs). The immunocytochemical (ICC) analysis of 334 cytological specimens demonstrated that the use of our selected panel of MAbs could allow a more efficient identification of SPTs in comparison with conventional morphology. This diagnostic improvement was statistically significant (P < 0.0001). The present findings show that the immunophenotyping of effusions and FNAs, providing a more accurate and objective identification of SPTs, may have significant therapeutic and epidemiological relevance.

Antifungal sterol biosynthesis inhibitors

During the course of the last decade, the development of SBIs, and particularly sterol biomethylation inhibitors, has been based on the rational design approach. Successful though this approach has been in elucidating sterol biomethylation enzymology, its limitations are becoming apparent from the findings that: (i) 24,25-double bond metabolism gives rise to cholesterol and ergosterol in a mechanistically similar manner, (ii) 25-azasterols are harmful to human physiology, and (iii) side-chain modified sterols designed to inhibit the SMT enzyme in S. cerevisiae may be ineffective or operate by another kinetic mechanism in a related organism, rendering it therapeutically nonuseful. Nevertheless, it may be possible to ultimately capitalize on the unique aspects of sterol biomethylation chemistry and enzymology to design taxa-specific inhibitors. With increased understanding of the structure and function of SMT enzymes in different fungi, it should be possible to prepare novel mechanism-based inactivators to control SMT activity uniquely and with high specific activity.

Increase in cytokine production (IL-1 beta, IL-6, TNF-alpha but not IFN-gamma, GM-CSF or LIF) by stimulated whole blood cells in postmenopausal osteoporosis

Postmenopausal osteoporosis is a progressive disorder characterized by a decreased bone mass and increased susceptibility to fractures. Several investigations have suggested that one of the mechanisms through which estrogen prevents bone loss was a modulation on secretion or release of various cytokines that are known to influence bone remodeling, even if some recent data have challenged this hypothesis. However, in established osteoporosis, the possibility that enhanced cytokines activity may account for the progression of this disease remains unclear and controversial. We sought here to determine whether production of IL-1 beta, IL-6, TNF-alpha, IFN-gamma, GM-CSF and LIF, after direct stimulation in whole blood, was different in healthy (n = 30) or osteoporotic postmenopausal women (n = 24) and whether lumbar bone density (1-BMD) correlated with the values of cytokine production observed in these conditions. A significant difference was observed between the osteoporotic and control subjects for IL-1 beta (p < 0.0001), IL-6 (p < 0.001) and TNF-alpha (p = 0.027) productions, the values being higher in the osteoporotic women. No significant differences between the groups were observed for IFN-gamma (p = 0.51), GM-CSF (p = 0.70) or LIF (p = 0.97). In the whole population, statistically significant negative correlations were observed between lumbar BMD and IL-1 beta (r = -0.46) (p < 0.0005), IL-6 (r = -0.50) (p < 0.0001) and TNF-alpha (r = -0.39) (p < 0.005) production while no such correlations were observed for IFN-gamma, GM-CSF or LIF. In conclusion, the study of cytokine production by immune cells cultured in autologous whole blood suggests that in women more than 10 years past the menopause and presenting a decrease in lumbar bone density corresponding to the new WHO definition of "osteoporosis', production of IL-1 beta, IL-6 and TNF-alpha is still increased compared to controls matched for age and ovarian function, while no differences are reported for IFN-gamma, GM-CSF or LIF production.