Influence of beta block and autonomic nerve block on the recovery time of the sinus node in sick sinus syndrome and carotid sinus syndrome

In order to evaluate the relative role of the automatic nervus system and of the intrinsic electrophysiologic properties on the sinus node function, we measured the corrected sinus node recovery time before and after autonomic nervous system blockade in 24 patients. Fourteen had a sick sinus syndrome, five had a carotid sinus syncope, two had syncope of unknown origin associated with bradycardia. Beta blockade was obtained by infusing metoprolol intravenously at a dosage of 0.2 mg/kg; complete automatic blockade was achieved by further i.v. administration of atropine at a dosage of 0.04 mg/kg. After beta blockade, the corrected sinus node recovery time increased in patients with sick sinus syndrome and intrinsic slow heart rate, whereas it decreased in patients with carotid sinus syncope or with syncope and bradycardia. In patients with sick sinus syndrome and normal intrinsic heart rate the response was variable. A positive direct correlation was found between the changes of the corrected sinus node recovery time induced by beta blockade and those induced by autonomic blockade; that is, both either prolonged or shortened the corrected sinus node recovery time. The changes of the corrected sinus node recovery time after beta blockade alone were inversely correlated with the intrinsic heart rate. We conclude that patients with intrinsic depression of the sinus node have an increased sympathetic tone.     

Gynecologic infections in adolescence

BACKGROUND: Adolescence in the age bracket with the highest incidence of sexually transmitted diseases (STDs). An observational study was performed in symptomatic patients attending our Outpatient Clinic for STDs in order to evaluate the diffusion of genital infections in the adolescent population and the different epidemiological distribution compared to adults. METHODS: The incidence of these infections was compared in two groups of patients attending the clinic between April 1995 and April 1999. The first consisted of 54 teenagers (13-19 years-old) and the second, used as a control, consisted of 917 women of child-bearing age (20-40 years). All patients underwent clinical examinations and microbiological tests of vaginal secretions (bacterioscopic test on coloured plates using the Gram method, cold tests, cultural assay of bacteria and fungi, assay for (Chlamydia trachomatis, Mycoplasma spp., Neisseria gonorrhoeae, Herpes simplex virus). RESULTS: The most common genital infection in teenagers was candidosis (35% vs 23.9%), followed by bacterial vaginosis (31.9% vs 25.8%) and mixed flora vaginitis (25.9% vs 22.6%). HSV was found in 1.8% of adolescents (vs 0.6%), in selected cases, Chlamydia and Mycoplasma were present in 16.6% (vs 1.1%) and 50% (vs 28%) of teenagers respectively. CONCLUSIONS: All genital infections were more frequent in the study population of adolescents compared to the control group. The adolescent population should be the target of a serious and systematic programme of prevention in order to ward off the sequelae of early and often irresponsible sexual activity.     

Malignant glomus tumor of the leg developed in the context of a superficial typical glomus tumor

A 41-year-old man presented with a 2-cm painful subcutaneous nodule in his right leg, which had been present for more than 10 years and was recently enlarging. Histologically, the tumor was composed of sheets and nests of cells with variable cytomorphology, including typical round/ovoid glomus cells with clear cytoplasm and well-defined borders, small cells, and spindle cells. Numerous medium to large vessels were present. Nodules with moderate to high cellularity, nuclear atypia, and frequent mitotic figures (42 per 50 high-power fields) were noted. Immunohistochemistry showed cytoplasmic and membranous expression of smooth-muscle actin, vimentin, and membranous expression of type IV collagen. Whereas superficiality, dimensions, and long-term follow-up may suggest classification as a symplastic or uncertain potential glomus tumor (GT), histological features and immunoprofile are indicative of malignant nodules developed in a typical GT. The follow-up has been negative for recurrence/metastases. A search of the literature revealed 17 cases of malignant GTs between 1995 and 2010, all fatal, of which 10 had skin as the primary site.     

Facial basal cell carcinoma: analysis of recurrence and follow-up strategies

Rates of recurrence after incomplete surgical excision of basal cell carcinoma (BCC) range from 4 to 16.6% of analyzed cases. The aim of the present study was to identify the predictive factors associated with facial BBC recurrence following excision and their influences, in order to establish a proper therapeutic strategy. A monocentric retrospective study was performed reviewing all BCCs surgically excised at the Institute of Plastic Surgery, University of Padua, with particular focus on the involvement of surgical margins and recurrence. Seven hundred and nineteen lesions in 605 patients were studied. Correlations between recurrence probability and various characteristics of BCC were analyzed using a logistic regression model. It was observed that incomplete excision, deep margin involvement, the presence of sclerodermiform or metatypic basaloid squamous cells, as well as pleomorphous histological variants and/or peritumoral inflammatory infiltrates, were all related to an increase in the probability of recurrence. BCC excision must be followed by individualized management with particular consideration for the localization, the histological type and other known predisposing factors; the treatment strategy and, in particular, the length of the surveillance period and the frequency of patient assessment should be evaluated on the basis of the recurrence probability outlined.     

Preparation of Block Copolymers with a Single Tg Based on Segments of Poly(oxy‐2,6‐dimethyl‐1,4‐phenylene) and Polycarbonate of Bisphenol A

Summary: The synthesis and the properties of block copolymers based on PPO and PC segments are reported. Copolymers that have a multi‐block structure are synthesized by a polycondensation reaction that employs oligomeric PPO and PC diol terminated with phosgene or bischloroformate of bisphenol A. In the reaction scheme two steps are involved: first, the reaction of one of the oligomeric diols (PPO or PC) with the bischloroformate or phosgene; second, the oligomeric bischloroformate is reacted with the other diol. The molecular characteristics of the prepared samples are studied by SEC, ¹H and ¹³C NMR, and FT‐IR spectroscopy. The thermal and rheological properties and the thermal stability have also been investigated by means of DSC, rotational rheometry, and TGA, respectively. Polymers that have a single glass transition temperature are obtained if low‐molecular‐weight segments are used. From a rheological point of view, these materials show a remarkably lower melt viscosity compared with a PPO homopolymer that has a comparable average molecular weight.

Rheometric curves of PPO‐b‐PC (3) compared with a commercial PPO.     

Cycle arrest and aneuploidy induced by zidovudine in murine embryonic stem cells

Zidovudine (3'-azido-3'-deoxythymidine; AZT) is a nucleoside analogue widely used for the treatment of acquired immune deficiency syndrome (AIDS). Medical guidelines recommend the use of AZT by pregnant women in order to reduce risk of HIV vertical transmission. Although it is efficacious, little is known about the side effects of AZT on embryonic development. In this sense, we used murine embryonic stem (mES) cells as a model to investigate the consequences of AZT exposure for embryogenesis. Firstly, mES colonies were incubated with AZT (50 or 100 μM) and cell cycle profile was evaluated. While 27.7 ± 5.43% of untreated mES cells were in G2/M phase, this percentage raised to 45.96 ± 4.18% after AZT exposure (100 μM). To identify whether accumulation of cells in G2/M phase could be related to chromosome missegregation with consequent cell cycle arrest, aneuploidy rate was evaluated after AZT treatment. Untreated colonies presented 39.6 ± 8.4% of cells aneuploid, while after AZT 100 μM treatment, the proportion of aneuploid cells raised to 67.8 ± 3.4% with prevalence of chromosome loss. This event was accompanied by micronuclei formation as AZT 100 μM treated mES cells presented a 2-fold increase compared to untreated ones. These data suggest that AZT exerts genotoxic effects and increases chromosome instability at early stages of embryonic development.