HPLC-MS/MS measurement of lidocaine in rat skin and plasma. Application to study the release from medicated plaster.

A simple, sensitive HPLC-MS/MS method was developed and validated for the determination of lidocaine in skin and plasma of rats. The methods were established and validated assessing lower limit of quantitation (LLOQ), linearity, intra and inter-day precision and accuracy, selectivity, recovery and matrix effect. Chromatography was done on a Gemini column embedded with C18 stationary phase (50 mm × 2.0 mm, 5 µm particle size), using a gradient with mobile phases consisting of 0.1% HCOOH in bidistilled water and 0.1% HCOOH in acetonitrile. The mass spectrometer worked with electrospray ionization in positive ion mode and selected reaction monitoring, using target ions m/z 235.10 for lidocaine and m/z 245.10 for lidocaine-d10, used as internal standard. RESULTS: The linearity of the method was in the ranges of lidocaine concentrations 10.0-200.0 ng/mL for skin homogenate (accuracy 94.1-105.5%; R2 ≥ 0.998) and 0.025-2 ng/mL for plasma (accuracy 96.2-104.8%; R2 ≥ 0.996). The intra- and inter-day precision and accuracy determined on three quality control samples (20, 75 and 170 ng/mL for skin and 0.075, 0.4 and 1.5 ng/mL for plasma) were ≤4.2% and 103.8-108.2% for skin and ≤12.4% and 95.5-101.4% for plasma. The LLOQ was 10 ng/mL in skin homogenate and 0.025 ng/mL in plasma. The applicability of the method was demonstrated by measuring lidocaine in skin and plasma after exposure to medicated patches containing 5% lidocaine.

Congenital hypothyroidism with gland in situ: diagnostic re-evaluation.

In the past, most congenital hypothyroidism (CH) children with thyroid gland in situ were considered to be affected by hormonogenesis defect. Nowadays, the improved sensitivity of neonatal screening, novel insights into the pathogenic mechanisms and the advances of genetic analyses have reopened the discussion about the etiology of CH with thyroid in situ. We report the etiological re-evaluation of 31 children with thyroid in situ, who had been identified by the CH screening program. The purposes of this re-evaluation were: a) to investigate the definitive diagnosis and pathogenetic mechanism of CH with thyroid in situ in eligible children suspected of dyshormonogenetic defect and b) to verify the adequacy of the treatment schedules. Thirty out of 31 children were affected with permanent hypothyroidism and only one child was euthyroid at re-evaluation (transient CH). Thyroid hormone organification defects were present in less than half of the CH patients with thyroid in situ (13/30); a higher prevalence of partial defects of iodine organification than severe or complete forms was found. An inactivating TSH-receptor gene mutation was found in only one patient without iodine organification defect. Some questions remain unanswered concerning the adequacy of the schedules of treatment, particularly about the proper treatment of mild and borderline forms of CH.

Cyclins of phases G1, S and G2/M are overexpressed in aneuploid mammary carcinomas.

Expression of cyclins A, B1 and D1 in human breast cancer was analyzed using dual-parameter flow cytometry with simultaneous evaluation of the DNA content. The asynchronous MCF-7 breast adenocarcinoma cells were used to implement flow cytometry analysis and to analyze the cell cycle distribution of cyclins. The patterns of the cyclin expression were also analyzed in vivo in fresh tissue specimens of human breast carcinomas. The combined measurement of DNA and cyclins showed a higher cyclin expression in aneuploid (11.5 +/- 2.0%, 4.3 +/- 1.1%, and 19.5 +/- 3.4% positive cells for cyclins A, B, and D1, respectively) than in diploid carcinomas (3.9 +/- 1.2%, 1.1 +/- 0.4%, and 5.0 +/- 1.2% positive cells for cyclins A, B, and D1, respectively). A positive relationship was also found between cyclin A and D1 expression and H(3)-thymidine labeling index. In the in vitro model, the asynchronous growing MCF-7 cells showed a variable number of cells expressing cyclins in an unscheduled way, unrelated to the phase at which these cyclins are expressed in normal cells. A similar condition was also observed in tumors. In conclusion, the data showed a deregulated expression of cyclins in a transformed adenocarcinoma cell line and in breast tumors. Furthermore, overexpression of these proteins is related to the aneuploid and high proliferative activity of human mammary carcinomas.

Cyclin-D1 expression in node-positive (N+) and node-negative (N-) infiltrating human mammary carcinomas.

Cyclin-D1 (CD1) expression was analyzed in human mammary carcinomas by immunohistochemical (IHC) and flow-cytometry (FCM) methods: 52.5% and 50% of cases were strong expressors of CD1 by IHC and FCM analysis respectively. The percentage of CD1-positive cells was especially high in node-negative (N-) estrogen-receptor-positive (ER+) tumors, probably as a consequence of CD1 induction by estrogens in steroid-responsive tissues. However, CD1 expression was not related to ER positivity in node-positive tumors (N+). An interesting relationship between CD1 expression and H3-thymidine labelling index (H3Td-LI) was also found: CD1 and H3Td-LI were unrelated in N- tumors, while high CD1 expression was observed in N+ tumors with high DNA synthesis, as assessed by H3Td-LI. The combined measurement of DNA and CD1 showed that 27 specimens were aneuploid, 19 of them (19/27; 70%) strongly expressing CD1. Further studies are needed to clarify the role of CD1 in DNA abnormality of breast tumors. However, we cannot exclude that the CD1 may be differently de-regulated in the last phase of tumor progression, and that CD1 over-expression may contribute to the aneuploidy of mammary carcinomas.

Primary chemotherapy in locally advanced breast cancer (LABC): effects on tumour proliferative activity, bcl-2 expression and the relationship between tumour regression and biological markers.

The rate of tumour cell proliferation evaluated by the [3H]-thymidine labelling index ([3H]-dT-LI) is known to be an independent prognostic factor in patients with operable breast cancer and significantly predicts the response to chemotherapy in patients with advanced disease. In locally advanced breast cancer (LABG), we examined whether chemotherapy induced modifications in [3H]-dt-LI, and bcl-2 expression and their relationship with tumour regression and prognosis. 70 LABC patients received three courses of primary chemotherapy (FEC: 5-fluorouracil 600 mg/m2, epidoxorubicin 60 mg/m2, cyclophosphamide 600 mg/m2, followed by surgery and subsequent adjuvant chemotherapy consisting of three courses of FEC alternated with three courses of CMF (cyclophosphamide 600 mg/m2, methotrexate 40 mg/m2, 5-fluorouracil 600 mg/m2). Tumour biological markers were evaluated on diagnostic biopsy, before primary chemotherapy and at surgery. Tumour cell proliferation was determined by [3H]-dT-LI, whilst bcl-2 expression was examined by immunohistochemical staining. The overall response rate to primary FEC was 74.3% (95% confidence interval 57.6-83.2%). The response rate correlated with high [3H]-dT-LI: 88% (29/33) of patients with high [3H]-dT-LI achieved an objective response compared with 62% (23/37) of patients with low [3H]-dT-LI (P = 0.014). The 3 patients achieving a pathological complete response after induction treatment had high proliferative tumours. The highest 2-year relapse free survival (66.6%) was observed in patients with low [3H]-dT-LI after primary chemotherapy. The median bcl-2 expression values before and after primary chemotherapy were 0% (range 0-80) and 30% (range 0-90), respectively (P = 0.03). Our data indicate that primary chemotherapy can modulate tumour cell kinetics and apoptosis-related genes. Pretreatment proliferative activity correlated with tumour response, whilst post-treatment [3H]-dT-LI correlated with relapse free survival.

Antipyretic and platelet antiaggregating effects of nimesulide.

Nimesulide strongly inhibited ex vivo platelet aggregation in guinea-pigs after both single and repeated (once daily for 5 days) oral dosing, irrespective of the aggregating agent used (adenosine diphosphate, arachidonic acid or collagen). Its potency was consistently greater than that shown by either ticlopidine or acetylsalicylic acid. In both oral and rectal administration, nimesulide proved to be more active and longer lasting than paracetamol in inhibiting fever induced in rats injected subcutaneously with brewer's yeast.

Cardiovascular activities of the new potent and long-lasting antihypertensive calcium entry blocker (+-)-3-ethyl,5-methyl,2- ([2-(formylamino)-ethyl]- thiomethyl)-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicar box ylate.

BBR 2160 ((+-)3-ethyl,5-methyl,2-([2-(formylamino)-ethyl]- thiomethyl)-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarb oxy late, CAS 118587-22-7) is a new calcium entry blocker (CEB) which completely displaces 3H-nitrendipine from binding sites, is 10 times more potent than amlodipine (A) and equiactive with nifedipine (N). On the rat aorta contracted by 10 mmol/l Ca++, or 45 mmol/l K+, BBR 2160 shows higher CEB activity than N and A, achieving the maximum effect on voltage operated channels-induced contractions in 6 h, while N takes about 2 h. BBR 2160, N and A negatively affect the chronotropism on spontaneously beating, and inotropism on electrically driven guinea pig atria, respectively. In vitro BBR 2160 has marked vasoselectivity. Administered orally to conscious hypertensive rats (SHR) and renal hypertensive dogs (RHD), it caused a dose-dependent reduction in systolic blood pressure with a relatively slow onset, peak effect at 3-6 h and duration over 6 h. BBR 2160 and A have more pronounced activity on SHR than on normotensive rats (NR) (ED20 NR/SHR 3.3 for both compounds), while the antihypertensive and hypotensive activities of N are in the same dose-range (ED20 NR/SHR 1.3). No tolerance develops to the antihypertensive effects of BBR 2160 after five days' dosing up to 3.2 mg/kg in SHR and 1 mg/kg in RHD. In instrumented conscious normotensive dogs BBR 2160, N and A mostly lower diastolic blood pressure and total peripheral resistance, and do not increase total oxygen consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

[Sodium nitroprusside and inhibition of coronary vasoconstriction in isolated hearts of guinea pigs]. / Nitroprussiato di sodio ed inibizione della vasocostrizione coronarica in cuori isolati di cavia.

Recent data suggest that nitrate compounds, beside determining vasodilatation by cGMP-mediated Ca++ uptake in the sarcoplasmic reticulum, may also inhibit vasoconstriction by reducing phosphatidyl inositol bisphosphate hydrolysis, a major step in the biochemical pathway responsible for vasoconstriction induced by a variety of agents including angiotensin II (AII). We assessed the inhibitory effects of Na-nitroprusside (NP) on the coronary resistances induced by increasing doses of AII in Krebs perfused (basal pressure: 2.5-3 KPa) Guinea-pig isolated hearts. AII bolus injections (5 to 100 ng) were given before and 10 min after a 7.6.10(-8) to 7.6.10(-6) M infusion of NP for 10 min. AII produced a highly reproducible, linearly dose-related, increase in perfusion pressure (PP) (5 ng: 4.4 +/- 1.16; 10 ng: 8.1 +/- 2.1; 25 ng: 18.7 +/- 3.06; 50 ng: 23.6 +/- 2.31; 100 ng: 30 +/- 1.37 mmHg) that was persistently and dose-dependently inhibited by NP. Well after (greater than 10 min) full recovery from the initial NP-induced vasodilatation and drop in PP its inhibitory effect was observed, varying from 22.1% at the maximal AII and minimal NP does and 90.6% at the minimal AII and maximal NP doses. This study demonstrates that, apart from causing the well-known immediate vasodilatory response by stimulation of cGMP synthesis, NP also causes delayed inhibition of AII-induced coronary vasoconstriction, possibly by preventing phosphatidyl inositol hydrolysis.

Effects of a new calcium antagonist, Rec 15/2375, on cardiac contractility of conscious rabbits.

The new calcium antagonist Rec 15/2375, supposed to be selective for the vascular tissue, was compared to nifedipine, a non-selective agent that reduces blood pressure and impairs cardiac inotropism as well. Six rabbits, chronically catheterized and continuously monitored for systemic blood pressure, heart rate and the isovolumic contractility index dP/Tmax, were alternatively treated with Rec 15/2375 and nifedipine, according to a randomized cross-over design. Both drugs were given under either autonomically intact (AI) or suppressed (AS) heart function control, induced by cholinergic and beta-adrenoceptor blockade. The two agents reduced mean arterial blood pressure comparably and dose-dependently (P less than 0.01) under both experimental conditions (from 10 to 40%), thus causing heart rate to increase reflexly (P less than 0.01), similarly between drugs in AI rabbits, whereas the AS manoeuvre totally abolished such a response. Cardiac contractility, on the other hand, displayed opposing behaviour between the two drugs. Rec 15/2375 caused mild but significant (P less than 0.01) increases, which were similar at all doses (+10, +15%) and insensitive to the AS intervention, whereas nifedipine caused dose-dependent reductions (from -10 to -60%; P less than 0.01) of comparable intensity as mean blood pressure decrease in both protocols. We conclude that Rec 15/2375 effectively lowers blood pressure with no impairment, unlike nifedipine, of cardiac inotropism and we discuss the possibility that dP/dTmax may be increased as a result of the haemodynamic rearrangement following after-load reduction.