Severe rhabdomyolysis with hypoglycemia in an adult patient with carnitine palmitoyltransferase II deficiency

Carnitine palmitoyltransferase II (CPT2) deficiency is an inherited disorder associated with rhabdomyolysis. The adult form of CPT2 deficiency is usually "benign", characterized by episodes of rhabdomyolysis without extramuscular manifestations and with a good outcome, while the infantile type characteristically presents with severe metabolic symptoms such as hypoketotic hypoglycemia. We present here a case of severe rhabdomyolysis with acute renal failure and hypoglycemia in an adult patient with CPT2 deficiency.

Methotrexate selectively modulates TH1/TH2 balance in active rheumatoid arthritis patients

OBJECTIVE

The mechanism by which low dose methotrexate (MTX, the gold standard treatment for rheumatoid arthritis) exerts its anti-inflammatory effect in rheumatoid arthritis (RA) patients is still debated. Lately, the MTX immunosuppressive effect has been related to apoptosis, especially in active RA patients, with ROS involvement.

METHODS

In the present research we investigated MTX oxidative effect and its ability to modulate immune balance in active versus non-active RA patients.

RESULTS

Our results show that MTX induces IL-10 secretion (a TH2 cytokine) and significantly reduces TH1 profile in Peripheral Mononuclear Cells (PMNC) derived from active RA patients (n=28). Additionally, we found that MTX modulates the immune status towards TH2 dominance by decreasing the IL-12R and the CXCR3 receptors typical for the TH1 population. Moreover, MTX was found to inhibit the production of nitric oxide (NO) in these patients, a phenomenon that might contribute to MTX action toward cytokine homeostasis. A significant correlation was found between MTX IL-10 induction and NO inhibition in active RA patients.

CONCLUSION

Our data suggest that, in active RA patients, apoptosis induction by MTX may be primarily due to IL-10 production via modulation of oxidative stress, which may restore the critically important immune balance. These findings may contribute to determining which group of RA patients may better respond to MTX therapy.

Old and emerging therapies in chronic hepatitis C: an update

The main goal of therapy in hepatitis C virus (HCV) infection is to achieve a sustained virological response currently defined as undetectable HCV-RNA in peripheral blood determined with the most sensitive polymerase chain reaction technique 24 weeks after the end of treatment. This goal is practically equivalent with eradication of HCV infection and cure of the underlying HCV-induced liver disease. The current standard in hepatitis C treatment consists in combination regimens of pegylated interferon-alpha (Peg-INF-alpha) with Ribavirin (RBV). Such treatment schemes are quite successful in patients with HCV genotypes 2 and 3 infections achieving HCV eradication rates of 75-90%. However, they are much less effective in patients with genotypes 1 and 4 infections with eradication rates ranging between 45% and 52%. Moreover, they have several, and sometimes severe, adverse effects and contraindications, further limiting their efficacy and applicability in an appreciable number of patients with chronic HCV-induced liver disease. Therefore, the need for improvement of existing therapies and for development of new effective, safe and tolerable drugs is a matter of great clinical relevance and importance. In this article, recent improvements in the current standard of therapy with IFN-alpha and RBV in various subsets of patients with chronic hepatitis C and in the clinical development of new emerging drugs, particularly small molecules, will be reviewed and commented. The article is divided in two main parts: (i) improvements in the standard combination therapies and schemes of approved Peg-INF-alpha with RBV and expectations from new interferons, interferon inducers and alternatives to RBV; (ii) new drugs for HCV in clinical development focusing mostly on specific inhibitors of HCV and less so on other drugs including immune therapies.

An information-theoretical model for breast cancer detection

OBJECTIVES

Formal diagnostic modeling is an important line of modern biological and medical research. The construction of a formal diagnostic model consists of two stages: first, the estimation of correlation between model parameters and the disease under consideration; and second, the construction of a diagnostic decision rule using these correlation estimates. A serious drawback of current diagnostic models is the absence of a unified mathematical methodological approach to implementing these two stages. The absence of a unified approach makes the theoretical/biomedical substantiation of diagnostic rules difficult and reduces the efficacy of actual diagnostic model application.

METHODS

The present study constructs a formal model for breast cancer detection. The diagnostic model is based on information theory. Normalized mutual information is chosen as the measure of relevance between parameters and the patterns studied. The "nearest neighbor" rule is utilized for diagnosis, while the distance between elements is the weighted Hamming distance. The model concomitantly employs cellular fluorescence polarization as the quantitative input parameter and cell receptor expression as qualitative parameters.

RESULTS

Twenty-four healthy individuals and 34 patients (not including the subjects analyzed for the model construction) were tested by the model. Twenty-three healthy subjects and 34 patients were correctly diagnosed.

CONCLUSIONS

The proposed diagnostic model is an open one, i.e. it can accommodate new additional parameters, which may increase its effectiveness.

The incidence of arm edema in women with breast cancer randomized on the National Surgical Adjuvant Breast and Bowel Project study B-04 to radical mastectomy versus total mastectomy and radiotherapy versus total mastectomy alone

PURPOSE

To determine the incidence and factors associated with the development of arm edema in women who participated in the National Surgical Adjuvant Breast and Bowel Project (NSABP) study B-04.

METHODS AND MATERIALS

Between 1971 and 1974, the NSABP protocol B-04 randomized 1,665 eligible patients with resectable breast cancer to either (1) the Halstead-type radical mastectomy; (2) total mastectomy and radiotherapy to the chest wall, axilla, supraclavicular region, and internal mammary nodes if by clinical examination axillary nodes were involved by tumor; and (3) for patients with a clinically uninvolved axilla, a third arm, total mastectomy alone. Measurements of the ipsilateral and contralateral arm circumferences were to be performed every 3 months.

RESULTS

There was at least one recorded measurement of arm circumferences for 1,457 patients (87.5% of eligible patients). There were 674 women (46.3%) who experienced arm edema at some point during the period of follow-up until February 1976. For radical mastectomy patients, total mastectomy and radiotherapy patients, and total mastectomy patients alone, arm edema was recorded at least once in 58.1%, 38.2%, and 39.1% of patients, respectively (p<.001) and at last recorded measurement in 30.7%, 14.8%, and 15.5%, respectively (p=or<.001). Increasing body mass index (BMI) also showed a statistically significant correlation with arm edema at any time (p=.001) and at last assessment (p=.005).

CONCLUSIONS

Patients who undergo mastectomy, including those whose treatment plans do not include axillary dissection or postoperative radiotherapy, suffer an appreciable incidence of arm edema.

Wetting, mixing, and phase transitions in Langmuir-Gibbs films

Millimolar bulk concentrations of the surfactant cetyltrimethylammonium bromide (CTAB) induce spreading of alkanes, H(CH(2))(n)H (denoted C(n)) 12< or =n< or =21, on the water surface, which is not otherwise wet by these alkanes. The novel Langmuir-Gibbs film (LGF) formed is a liquidlike monolayer comprising both alkanes and CTAB tails. Upon cooling, an ordering transition occurs, yielding a hexagonally packed, quasi-2D crystal. For 11< or =n< or =17 this surface-frozen LGF is a crystalline monolayer. For 18< or =n< or =21 the LGF is a bilayer with a crystalline, pure-alkane, upper monolayer, and a liquidlike lower monolayer. The phase diagram and film structure were determined by x-ray, ellipsometry, and surface tension measurements. A thermodynamic theory accounts quantitatively for the observations.

Alkyl-thiol Langmuir films on the surface of liquid mercury

The coverage dependent phase behavior of monolayers of alkyl thiols (CH3(CH2)(n-1)SH, denoted as CnSH) on mercury was studied for chain lengths 9 <or= n <or= 22, using surface tensiometry and surface-specific X-ray scattering methods. At low coverage, a disordered single layer of surface-parallel molecules is found for all n. At high coverage, a monolayer of standing-up molecules is formed, exhibiting well-ordered phases, the structure of which is n- and coverage-dependent. The molecular chains pack in a centered rectangular unit cell, with an approximately 27 degrees tilt from the surface normal toward nearest neighbors. The strong sulfur-mercury bond induces a noncentered unit cell for the headgroups, incorporating one mercury atom per two thiol molecules. The small but significant differences in structure of these films on gold and on mercury are discussed and assigned to the different structure of the subphase: long-range-ordered crystal for gold and short-range-ordered liquid for mercury.

An association between postoperative radiotherapy for primary breast cancer in 11 National Surgical Adjuvant Breast and Bowel Project (NSABP) studies and the subsequent appearance of pleural mesothelioma

OBJECTIVES

Among the minority of patients with pleural mesothelioma and no known exposure to asbestos, there have been case reports suggesting a possible association with previous radiotherapy. The association between radiotherapy for primary breast cancer and the subsequent occurrence of mesothelioma was investigated in women entered into 11 National Surgical Adjuvant Breast and Bowel Project (NSABP) prospective clinical trials for breast cancer.

METHODS

Follow-up information was obtained on 22,140 patients entered into 11 NSABP clinical trials for treatment of primary breast cancer between 1971 and 1994. Postoperative radiotherapy was administered to 9342 patients, mainly after lumpectomy. Postlumpectomy patients were treated with radiotherapy just to the ipsilateral breast and without regional nodal irradiation. There were 12,798 patients who did not have postoperative radiotherapy, and almost all had mastectomy.

RESULTS

Three pleural mesotheliomas were identified, and all occurred in the ipsilateral thorax of the irradiated patients (P = 0.009). All had received postlumpectomy breast irradiation for ductal carcinoma in situ. None had a known previous exposure to asbestos.

CONCLUSIONS

There appears to be a small but statistically significant increased risk of developing mesothelioma following radiotherapy administered for primary breast cancer. However, in absolute numbers, the risk is too small to be considered a contraindication to administering radiotherapy when indicated.

Metamaterial coatings for broadband asymmetric mirrors

We report the design and fabrication of nanostructured metal-dielectric mirrors with high reflectance asymmetries in the visible spectral range. Applying dispersion engineering principles to model a broadband and large reflectance asymmetry, we obtain a dielectric function for this metamaterial, closely resembling the effective permittivity of disordered metal-dielectric nanocomposites. Coatings realized by using disordered nanocrystalline silver films on glass substrates confirm the theoretical predictions, exhibiting symmetric transmittance, accompanied by large broadband reflectance asymmetries.

Breast skin doses from brachytherapy using MammoSite HDR, intensity modulated radiation therapy, and tangential fields techniques

Skin doses from brachytherapy using MammoSite HDR, Intensity Modulated Radiation Therapy (IMRT), and conventional tangential fields techniques were compared. For each treatment technique, skin doses were measured using paired thermoluminescent dosimeters placed on the patient's skin: (i) directly above the balloon catheter during MammoSite HDR brachytherapy treatments and (ii) 4 cm inside the treatment borders during the IMRT and conventional breast treatments. The mean dose measured was about 58% of the prescription dose for the patients treated using the MammoSite technique. On the other hand, for patients treated with IMRT and tangential fields, the mean dose was found to be about 69% and 71% of the corresponding prescription dose. This study suggests that in breast cancer radiation treatments the MammoSite HDR technique reduces skin doses compared to IMRT and tangential field techniques.

The surface structure of concentrated aqueous salt solutions

The surface-normal electron density profile rhos(z) of concentrated aqueous salt solutions of RbBr, CsCl, LiBr, RbCl, and SrCl2 was determined by x-ray reflectivity (XR). For all but RbBr and SrCl2 rhos(z) increases monotonically with depth z from rhos(z)=0 in the vapor (z<0) to rhos(z)=rhob of the bulk (z>0) over a width of a few angstroms. The width is commensurate with the expected interface broadening by thermally excited capillary waves. Anomalous (resonant) XR of RbBr reveals a depletion at the surface of Br- ions to a depth of approximately 10 A. For SrCl2, the observed rhos(z)>rhob may imply a similar surface depletion of Cl- ions to a depth of a few angstorms. However, as the deviations of the XRs of RbBr and SrCl2 from those of the other solutions are small, the evidence for a different ion composition in the surface and the bulk is not strongly conclusive. Overall, these results contrast earlier theoretical and simulational results and nonstructural measurements, where significant surface layering of alternate, oppositely charged, ions is concluded.

The Role for intensity modulated radiation therapy (IMRT) in pediatric population

The purpose of this study was to evaluate our initial experience on the use of IMRT in children with tumors in eloquent or critical locations. Twenty-two children with a median age of 12 years (range 1-17) were treated using IMRT for tumors which were within 2 cm of a critical structure. The treatment locations were spine [2], head and neck [5], abdominopelvic [8], and intracranial [7]. Eighty-two percent (82%) of patients were treated with curative intent despite most patients having advanced or metastatic disease and two patients having previously received standard external beam radiation. IMRT was delivered with a 6MV linear accelerator using dynamic multileaf collimators with a median of six fields. The median follow-up was five months [1-21]. The median administered dose was 45 Gy. The median planning treatment volume (PTV) was 105.4 cc. For the intracranial lesions, the mean doses to the pituitary, brainstem, cochlea, optic nerve, and lens were 31%, 42%, 17%, 27%, and 6% of the total dose, respectively. For the head and neck tumors, the mean doses to the spinal cord and parotid glands were 47% and 49%, respectively. For the pelvic tumors, the mean dose to the bladder, rectum, and small bowel were 51%, 63%, and 22%, respectively. Local failure occurred in one patient. IMRT resulted in substantial sparing of surrounding critical structures and acceptable local control rate for these tumors in children. Further follow-up is needed to assess long-term local control and late effects.

The surface structure of ionic liquids: Comparing simulations with x-ray measurements

The surface-normal electron density profile of an ionic liquid, [bmim][PF6], derived from x-ray reflectivity measurements, is compared with two independent molecular-dynamics simulations. It is shown that a meaningful comparison requires a detailed accounting for both thermal and nonthermal surface roughening effects. The former is due to thermally excited capillary waves, and the latter is due to the molecular zero-point motion and form. These quantities influence very significantly, but differently, the simulated and measured density profiles. Stripping off these effects from both types of profiles yields the intrinsic structure factor of the surface. The simulated intrinsic structure factors are found to deviate considerably from the measured one. The introduction of additional ad hoc surface roughness to the simulated profiles greatly reduces the deviation, however, no physical origin for this effect can be identified. The method employed in this study should prove useful for simulation-experiment comparisons of other liquid surfaces, provided they obey capillary-wave theory, as do almost all liquid surfaces studied to date by x-ray reflectivity.

Low Locoregional Recurrence Rate Among Node-Negative Breast Cancer Patients With Tumors 5 cm or Larger Treated by Mastectomy, With or Without Adjuvant Systemic Therapy and Without Radiotherapy: Results From Five National Surgical Adjuvant Breast and Bowel Project Randomized Clinical Trials

Purpose

Lymph node (LN) –negative breast cancer tumors ≥ 5 cm occur infrequently, and their optimal management is not well defined. In this study, we assess patterns of locoregional failure (LRF) in LN-negative patients who underwent mastectomy, either with or without adjuvant chemotherapy or hormonal therapy and without postmastectomy radiation therapy (PMRT).

Patients and Methods

Of 8,878 breast cancer patients enrolled onto National Surgical Adjuvant Breast and Bowel Project B-13, B-14, B-19, B-20, and B-23 node-negative trials, 313 had tumors that were 5 cm or larger (median, 5.5 cm; range, 5.0 to 15.5 cm) at pathology and were treated by mastectomy. Median follow-up time was 15.1 years. Therapy included adjuvant chemotherapy in 34.2% of patients; tamoxifen in 21.1%; chemotherapy plus tamoxifen in 19.2%; and no systemic therapy in 25.5%.

Results

Twenty-eight patients experienced LRF. The overall 10-year cumulative incidences of isolated LRF, LRF with and without distant failure (DF), and DF alone as first event were 7.1%, 10.0%, and 23.6%, respectively. Cumulative incidences for isolated LRF as first event for patients with tumors of 5 cm or more than 5 cm were 7.0% and 7.2%, respectively (P = .9). For patients who underwent no systemic treatment, chemotherapy alone, tamoxifen alone, or chemotherapy plus tamoxifen, the incidences were 12.6%, 5.6%, 4.6%, and 5.3%, respectively (P = .2). The majority of failures occurred on the chest wall (24 of 28 patients). Multivariate analysis did not identify significant prognostic factors for LRF.

Conclusion

In patients with LN-negative tumors ≥ 5 cm who are treated by mastectomy with or without adjuvant systemic therapy and no PMRT, LRF as first event remains low. PMRT should not be routinely used for these patients.

Surface freezing in binary alkane-alcohol mixtures

Surface freezing was detected and studied in mixtures of alcohol and alkane molecules, using surface tensiometry and surface-specific x-ray scattering methods. Considering that surface freezing in pure alkanes forms an ordered monolayer and in alcohols it forms an ordered bilayer, the length mismatch repulsion was minimized by varying the carbon number of the alkane component around 2n, where n is the carbon number of the alcohol molecule. A solutionlike behavior was found for all mixtures, where the ideal liquid mixture phase-separates upon freezing both in the bulk and the surface. The solid exhibits a herringbone crystalline phase below an alkane mole fraction phi(t) approximately 0.8 and a rotator phase above it. The surface frozen film below phi(t) is an alkane monolayer exhibiting a next-nearest neighbor molecular tilt of a composition-dependent magnitude. Above phi(t), no diffraction peaks were observed. This could be explained by the intrinsically shorter-range order of the rotator phase and a possible proliferation of defects.

Does breast size affect the scatter dose to the ipsilateral lung, heart, or contralateral breast in primary breast irradiation using intensity-modulated radiation therapy (IMRT)?

PURPOSE

To evaluate the relationship between the primary breast volume and dose received by the ipsilateral lung, heart (for left-breast cancers), and contralateral breast during primary breast irradiation using intensity-modulated radiation therapy (IMRT).

METHODS AND MATERIALS

Sixty-five patients with breast carcinoma were treated using 6-MV photons with IMRT technique using the Eclipse Planning System following breast conserving surgery. All patients had a treatment planning CT scan. The primary breast, ipsilateral lung, and heart were contoured on the axial CT slices. The primary breast volume was calculated using the Eclipse Planning System. The mean ipsilateral lung and heart doses were obtained from the dose-volume histogram. The contralateral breast dose was measured using paired thermoluminescent dosimeters (TLDs) placed on the patient's contralateral breast, 4 cm from the center of the medial border of the primary breast irradiation field.

RESULTS

The mean dose delivered with photons to the primary breast for all patients was 49.97 Gy. The mean volume of the primary irradiated breast was 1167.9 cc. As a percentage, the mean ipsilateral lung, heart, and contralateral breast doses were 11.2%, 6.1%, and 7.2%, respectively. The primary breast volume positively correlated with the contralateral breast dose (P < 0.0005). There was no significant correlation between the breast volume and the ipsilateral lung or heart dose (P = 0.463 and 0.943, respectively).

CONCLUSION

This study suggests that the primary breast size significantly affects the scatter dose to the contralateral breast but not the ipsilateral lung or heart dose when using IMRT for breast irradiation.

Phase II study of high-dose chemotherapy before radiation in children with newly diagnosed high-grade astrocytoma: final analysis of Children's Cancer Group Study 9933

BACKGROUND

High-grade astrocytomas (HGA) carry a dismal prognosis and compose nearly 20% of all childhood brain tumors. The role of high-dose chemotherapy (HDCT) in the treatment of HGA remains unclear.

METHODS

In a nationwide study, The Children's Cancer Group (CCG) prospectively evaluated 102 children with HGA and postoperative residual disease for efficacy and toxicity of four courses of HDCT before radiotherapy (RT). Patients were randomly assigned to one of three couplets of drugs: carboplatin/etoposide (Regimen A), ifosfamide/etoposide (Regimen B), or cyclophosphamide/etoposide (Regimen C). After HDCT, all patients were to receive local RT followed by lomustine and vincristine. Twenty-six patients were excluded after central neuroradiographic review (n = 8) or pathology review (n = 18).

RESULTS

Of 76 evaluable patients (median age, 11.95 yrs; range, 3-20 yrs), 30 patients relapsed during HDCT, and 11 others did not complete HDCT because of toxicity. Nonhematologic serious toxicities were common (29%), and 21% of patients did not receive RT. Objective response rates were not associated with amount of residual disease and did not statistically differ between regimens: 27% (Regimen A), 8% (Regimen B), and 29% (Regimen C). Overall survival (OS) was 24% +/- 5% at 5 years and did not differ between groups. Median time to an event was longest for Regimen A (283 days compared with 83 and 91 days for Regimens B and C, respectively). The five-year, event-free survival (EFS) rate for all patients was 8% +/- 3% and 14% +/- 7% for Regimen A (P = 0.07).

CONCLUSIONS

OS and EFS were not affected by histologic grade. Patients who responded to HDCT had a nominally higher survival rate (P = 0.03 for trend). The authors conclude that these commonly used HDCT regimens provide no additional clinical benefit to conventional treatment in HGA, regardless of the amount of measurable residual tumor.

DNA-repair protein distribution along the tracks of energetic ions

A simple model of homogenous chromatin distribution in HeLa-cell nuclei suggests that the track of an energetic ion hits 30 nm chromatin fibers with a mean distance of 0.55 mum. To test this assumption, living HeLa-cells were irradiated at the irradiation setup of the ion microprobe SNAKE using the ion beams provided by the Munich 14 MV tandem accelerator. After irradiation, the distribution of 53BP1 protein foci was studied by immunofluorescence. The observed 53BP1 distribution along the tracks of 29 MeV (7)Li ions and 24 MeV (12)C ions differed significantly from the expectations resulting from the simple chromatin model, suggesting that the biological track structure is determined by cell nuclear architecture with higher order organisation of chromatin.

Intensity modulated radiation therapy (IMRT) reduces the dose to the contralateral breast when compared to conventional tangential fields for primary breast irradiation

PURPOSE

To determine the dose received by the contralateral breast during primary breast irradiation using IMRT compared to conventional tangential field techniques.

METHODS AND MATERIALS

Between March 2003 and March 2004, 83 patients with breast carcinoma were treated using 6, 10, or mixed 6/18 MV photons (65 with tangential IMRT technique and 18 with 3-dimensional technique using tangential fields with wedges) for primary breast irradiation following breast-conserving surgery. Paired thermoluminescent dosimeters (TLDs) were placed on each patient's contralateral breast, 4 and 8 cm from the center of the medial border of the tangential field. The TLDs were left on the patient during a single fraction and then measured 24 h afterwards.

RESULTS

The mean dose delivered with photons to the primary breast for all patients was 4999 cGy (SD = 52) with a mean single fraction dose of 199 cGy (SD = 8). The mean percent of the prescribed dose to the contralateral breast measured at the 4- and 8-cm positions were 7.19% (SD = 2.28) and 4.63% (SD = 2.12), respectively, for patients treated with IMRT compared to 11.22% (SD = 2.73) and 10.70% (SD = 3.44), respectively, for the patients treated with conventional tangential field techniques. This represented a 36% and 57% reduction at the 4 and 8-cm contralateral positions, respectively, in the mean dose to the contralateral breast using IMRT compared to 3-D technique which was statistically significant (p < 0.0005, <0.0005, respectively).

CONCLUSION

Primary breast irradiation with tangential IMRT technique significantly reduces the dose to the contralateral breast compared to conventional tangential field techniques.

Phase I and pharmacokinetic study of the novel redox-active agent, motexafin gadolinium, with concurrent radiation therapy in patients with locally advanced pancreatic or biliary cancers

PURPOSE

To determine the maximum tolerated dose and dose-limiting toxicity (DLT) of the novel anticancer agent, motexafin gadolinium (MGd), administered concurrently with radiation therapy (RT) in patients with locally advanced pancreatic or biliary tumors. The pharmacokinetics of MGd were also evaluated.

METHODS

Cohorts of three to six patients were treated with escalating doses of MGd, administered three times per week for a total of 16 doses concurrent with RT. The dose of RT was fixed at 5,040 cGy, and given in 28 fractions, from Monday to Friday of every week. Plasma MGd concentrations were measured by high performance liquid chromatography.

RESULTS

Eight patients were treated at dose level 1 (2.9 mg/kg), with one DLT (grade 3 fever). Three patients were treated at dose level 2 (3.6 mg/kg), and two DLTs were noted. One DLT was grade 3 nausea and vomiting (N/V), and the other was grade 3 skin toxicity. The most common toxicity was N/V. There were no objective responses. The median survival was 6 months. The MGd plasma concentration versus time profile in each patient was best fit by a two-compartment, open, linear model. There was minimal accumulation of MGd in plasma with the three-times/week dosing schedule. Simulation of the time course of MGd in the peripheral compartment indicated that maximal MGd concentrations of 1-2 micromol/kg occurred between 4 and 6 h after MGd infusion.

CONCLUSION

Dose level 1 (2.9 mg/kg of MGd) is the recommended dose for combination with (RT) in phase II studies for locally advanced pancreatic and biliary cancers. Patient tolerance might be improved by modification of the RT schedule and antiemetic prophylaxis.

Low dose methotrexate induces apoptosis with reactive oxygen species involvement in T lymphocytic cell lines to a greater extent than in monocytic lines

BACKGROUND

The mechanism by which low dose methotrexate (MTX) exerts its anti-inflammatory and immunosuppressive effect in rheumatoid arthritis (RA) patients is still debated. Recently it has been related to the induction of apoptosis.

OBJECTIVE

We investigated the degree of apoptotic induction by MTX in lymphocytic (Jurkat T, EL4 T, and Raji B) and monocytic cell lines (U937 and THP1) and its relation to reactive oxygen species (ROS) generation, as a possible mechanism underlying the apoptotic events.

METHODS

All cell types were incubated with a range of MTX concentrations (0.001, 0.01, 0.1, 1, and 10 muM) for up to 24 h. Cytotoxicity was assessed by Trypan Blue exclusion and MTT test; cell size and granularity by forward and side scatters (FSC, SSC). Apoptosis was measured by Annexin V test and FDA polarization; and mitochondrial ROS generation by DHR123 probe and by NAC inhibition.

RESULTS

MTX significantly reduced cell viability and proliferation in all cell lines, being most effective in the Jurkat T lymphocytic line. The MTX cytotoxicity (at the optimal concentrations corresponding to low dose MTX therapy) was attributed to apoptosis, as suggested by morphological changes (shrinkage, increased granularity) and confirmed by Annexin V binding and FDA hyperpolarization. The apoptotic induction and the ROS generation (statistically correlated to apoptosis) were most pronounced in the Jurkat and EL4 T cell lines, and were partially inhibited by the antioxidant N-acetyl L-cysteine (NAC).

CONCLUSION

According to the present observations, MTX may most likely induce apoptosis through oxidative stress. The high susceptibility of T cell lines to MTX induced apoptosis may account for the beneficial effect of MTX treatment in rheumatoid arthritis, which is characterized by hyperproliferation of T cells.