Laser irradiation and balloon dilatation in experimental transluminal angioplasty

Percutaneous transluminal balloon angioplasty (PTA) is being currently used in patients with coronary artery disease. Laser irradiation (LI) has been effective in vaporizing atherosclerotic plaques. The purpose of this work was twofold: to compare PTA and LI techniques in the recanalization of experimental obstructive arterial lesions, and to evaluate the possibility of reducing the failures and local complications and increasing the success rate of PTA by the combined use of LI. Atherosclerotic iliac stenoses were induced in 27 rabbits; lesions were evaluated angiographically before and after intervention and were studied histologically and by electron microscopy. Argon-ion LI delivered through microlens-tip optic fibers reduced the stenotic area from 64.2 +/- 21.8% to 40.3 +/- 10.7% (n = 10, P less than .01) and PTA from 60.7 +/- 15.9% to 30.4 +/- 7.7% (n = 9, P less than .01). However, percentage reduction was higher in PTA-treated stenoses (48.4 +/- 10.1% vs 34.5 +/- 13.5%, P less than .0125). In eight more rabbits, low power LI (4.55 +/- 1.25 J) was delivered after PTA in dilated segments. Post-PTA LI further decreased stenoses (from 31.2 +/- 7.8% to 29.1 +/- 8.1%, P less than .0125); laser-irradiated segments showed diffuse carbonization of the disrupted intimal layer. The normalized transtenotic pressure gradient decreased significantly in all groups: LI reduced the gradient from .40 +/- .25 to .17 +/- .07 (P = .005); PTA from .37 +/- .14 to .11 +/- .04 (P = .001); LI after PTA from .40 +/- .16 to .12 +/- .06 (P = .001). Thus, LI is effective (less than PTA) in relieving experimental atherosclerotic stenoses and seems useful when combined with PTA.     

Treatment with para-chlorophenylalanine antagonises the emetic response and the serotonin-releasing actions of cisplatin in cancer patients.

To test the role of serotonin in chemotherapy-induced nausea and emesis, ten cancer patients were pretreated with the serotonin synthesis inhibitor para-chlorophenylalanine (PCPA). PCPA (2 g 8 hourly for 2 or 3 days prior to cisplatin) reduced the spontaneous urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA), inhibited the increase in urinary 5-HIAA induced by cisplatin and markedly attenuated the acute period of nausea and vomiting associated with the cytotoxic drug. These results indicate that gastrointestinal serotonin mediates cisplatin-induced emesis and that the amount of serotonin released by cisplatin is a major factor in determining the severity of the acute period of emesis experienced by the patient.     

Protective effect of 3-aminobenzamide,an inhibitor of poly (ADP-ribose) synthetase,against streptozotocin-induced diabetes

Summary The addition of 3-aminobenzamide (a potent inhibitor of poly(ADP-ribose)synthetase) into the incubation medium, prevents streptozotocin-induced inhibition of glucose-stimulated insulin release from isolated islets [control 142±14U·islet^–1·h^–1; streptozotocin (0.5mg/ml) 31±8; 3-aminobenzamide (l.0 mg/ml) 96±11; streptozotocin plus 3-aminobenzamide 122±19]. In vivo, intraperitoneal 3-aminobenzamide 300 mg/kg body weight prevents the appearance of overt diabetes in streptozotocin-treated rats. These protective effects of 3-aminobenzamide are dose-dependent and are similar to those exerted by nicotinamide. Taking into account that poly ADP-ribosylation is involved in the repair of damaged DNA, the protection exerted by 3-aminobenzamide against the diabetogenic effect of streptozotocin strongly supports the view that this acute effect may be a major consequence of the activation of DNA repair mechanisms in islet cells.     

Transradial Coronary Stenting: A United States Experience

Coronary stenting is associated with increased vascular complications and prolonged length of stay compared to balloon angioplasty. One strategy to address these concerns is performing the coronary stent procedure via the radial artery access site. The current study reviews the results of transradial coronary stenting in 300 patients in a United States hospital setting. All patients who underwent transradial coronary stent implantation at our center were included in the study. Procedural success, clinical events, vascular complications, post-procedure length of stay, and hospital charges were evaluated. Transradial coronary stenting was successfully performed in 283 of 300 patients (95%), although a significant learning curve was present. Nine complications occurred in the first 100 patients with only two in the last 100 patients. Unsuccessful procedures were due to inability to cross lesion in 3 patients (1%), emergency CABG in 6 patients (2%), stent embolization in 7 patients (2.3%), and 1 death (0.3%). Only one minor vascular complication occurred. The study confirms that transradial coronary stenting is feasible and safe, although new operators should be aware of potentially serious complications of the bare stent technique. Findings support the use of this alternative access site for coronary stenting in selected patients.     

Impact of Traits of Metabolic Syndrome on β-Cell Function and Insulin Resistance in Normal Fasting, Normal Glucose Tolerant Subjects

Abstract Objective: Metabolic syndrome, impaired fasting glucose (IFG), and impaired glucose tolerance (IGT) predict risk for type 2 diabetes mellitus (T2DM). To determine if increased risk preceded development of these abnormalities, β-cell function and insulin resistance were assessed in euglycemic subjects with and without traits of metabolic syndrome. Methods: A total of 562 apparently healthy Latin-American subjects were screened for metabolic syndrome [National Education Cholesterol Program Adult Treatment Panel III (NECP ATP III)]. Early pancreatic insulin response ΔInsulin(0-30)/ΔGlucose(0-30), Matsuda index, disposition index (DI), and homeostasis model assessment of insulin resistance (HOMA-IR) ratio were obtained from oral glucose tolerance testing (0-180?min). Results: ΔI(0-30)/ΔG(0-30), Matsuda index, DI, and HOMA-IR deteriorated in direct proportion with number of traits of metabolic syndrome, and with increases in glucose levels within the euglycemic range. DI was the most sensitive index. In subjects with 1, 2, 3, and 4-5 traits, DI was 21.4%, 40%, 57%, and 76% lower, respectively, than in subjects with no traits. As a single trait, abdominal obesity was associated with insulin resistance, whereas, low high-density lipoprotein cholesterol (HDL-C), alone or combined with high triglycerides, was not associated with insulin resistance or β-cell dysfunction. Combined impairments in β-cell function and insulin sensitivity were responsible for the increases in fasting and 2-h plasma glucose concentrations within the euglycemic range. Conclusions: Impaired β-cell function and increased insulin resistance are present much before development of metabolic syndrome, IFG, or IGT. β-Cell function and insulin sensitivity worsen in direct proportion with number of traits of metabolic syndrome and increases in glucose levels. Compared to abdominal obesity, low HDL-C±high triglycerides may bear a lesser weight in predicting risk of T2DM.     

Localization and quantification of fluorescent inclusions embedded in a turbid medium

A set-up, based on a CCD camera, to localize fluorescent inclusions in diffusing media was developed. This set-up allows one to acquire a huge dataset along two axes. This aspect is fundamental to performing a tomographic reconstruction in order to quantify the fluorescence amplitude in each voxel of the sample. Firstly, a simple analytical approach to recover the position of a single inclusion, embedded in a turbid medium, was developed. Then, we implemented a reconstruction algorithm to recover the position of one and two inclusions and to estimate their relative concentrations. Finally, we studied the dependence of reconstructed data on the number of injection points of excitation light and the number of detection points of fluorescence emission.     

Spectroscopic time-resolved diffuse reflectance and transmittance measurements of the female breast at different interfiber distances

The first, to our knowledge, in-vivo broadband spectroscopic characterization of breast tissue using different interfiber distances as well as transmittance measurements is presented. Absorption and scattering properties are measured on six healthy subjects, using time-resolved diffuse spectroscopy and an inverse model based on the diffusion equation. Wavelength-tunable picosecond-pulse lasers and time-correlated single-photon counting detection are employed, enabling fully spectroscopic measurements in the range 610 to 1040 nm. Characterization of the absorption and reduced scattering coefficients of breast tissue is made with the aim of investigating individual variations, as well as variations due to different measurement geometries. Diffuse reflectance measurements at different interfiber distances (2, 3, and 4 cm) are performed, as well as measurements in transmittance mode, meaning that different sampling volumes are involved. The results show a large variation in the absorption and scattering properties depending on the subject, correlating mainly with the water versus lipid content of the breast. Intrasubject variations, due to different interfiber distances or transmittance modes, correlate with the known structures of the breast, but these variations are small compared to the subject-to-subject variation. The intrasubject variations are larger for the scattering data than the absorption data; this is consistent with different spatial localization of the measurements of these parameters, which is explained by the photon migration theory.