Analytical thermal model for end-pumped solid-state lasers.

Fundamentally power-limited by thermal effects, the design challenge for end-pumped "bulk" solid-state lasers depends upon knowledge of the temperature gradients within the gain medium. We have developed analytical expressions that can be used to model the temperature distribution and thermal-lens power in end-pumped solid-state lasers. Enabled by the inclusion of a temperature-dependent thermal conductivity, applicable from cryogenic to elevated temperatures, typical pumping distributions are explored and the results compared with accepted models. Key insights are gained through these analytical expressions, such as the dependence of the peak temperature rise in function of the boundary thermal conductance to the heat sink. Our generalized expressions provide simple and time-efficient tools for parametric optimization of the heat distribution in the gain medium based upon the material and pumping constraints.

Thyroid hormones and the cardiovascular system: pathophysiology and interventions.

Thyroid dysfunction, however mild, can significantly affect the cardiovascular (CV) system. The effects of thyroid hormones may be viewed as genomic and non-genomic, with the former occurring over a longer time scale and both affecting structural and functional proteins in CV tissue. As the interplay between thyroid function and the CV system becomes elucidated, particularly in the context of a system biology approach, the heart failure phenotype is better understood. Symptomatology is related to disturbance in inotropic and chronotropic function. Moreover, biochemical changes reflected by thyroid function testing with the non-thyroidal illness syndrome can prognosticate and guide therapy in heart failure. In addition, empiric treatment with thyroid hormone analogues or T3 represent emergent and highly controversial interventions.

Cyclical clodronate is effective in preventing postmenopausal bone loss: a comparative study with transcutaneous hormone replacement therapy.

An investigative study was carried out for 2 years involving 124 randomly selected early postmenopausal women with spine bone mineral density (BMD) below the mean value of a normal premenopausal subject. After random division into three groups, the first 42 patients were treated with transcutaneous 17-beta-estradiol (50 micrograms daily), the second 42 were treated with cyclical intravenous clodronate (200 mg/month iv infusion), and the third group of 40 (controls) was left untreated. After 2 years, the total drop in BMD within the control group was more than 7% as opposed to the values of -0.14% +/- 0.93 in the estradiol group and 0.67% +/- 0.84 in the clodronate group. A change in BMD of < 1% was considered satisfactory, and this result was obtained in 32% of the controls, in 79% of the estradiol group where the percentage change in BMD moderately correlated with serum estradiol levels (r = 0.399), and in 90% of the clodronate-treated patients, in whom the percentage change in BMD inversely correlated with basal values of markers of bone turnover. Both estrogen and clodronate prevent postmenopausal bone loss. The response to transcutaneous hormone replacement therapy may be influenced by transcutaneous absorption and by a lower sensitivity to estrogen. Response to cyclical clodronate seems to be influenced by the rate of bone turnover. An interdosage interval ranging from 2-4 weeks appears suitable for most patients.

A randomized trial to evaluate the immunorestorative properties of thymostimulin in patients with Hodgkin's disease in complete remission.

A total of 19 Hodgkin's disease (HD) patients (12 male, 7 female) aged 26-67 years, who had been in complete unmaintained remission for 6 months or more when the study was initiated, were randomly given 50 mg thymostimulin (TS) i.m. daily (G1) or every other day (G2) for 35 days. A third group (G3) was not treated. Then TS, at the same dose was administered twice a week for the following 22 weeks in patients both initially receiving loading or intermittent TS treatment. When compared with age- and sex-matched controls, as a group, the patients' circulating OKT3+, OKT4+, OKT11+ and E-AETR+ cells were depressed (P less than 0.001 for both proportions and absolute numbers), whereas their OKT8+ cell population was not. Following 5 weeks of daily TS administration, the proportions and numbers of all T cell fractions significantly increased in G1 patients (P less than 0.03 for all the comparisons tested), while following intermittent TS treatment (G2) only the proportions of OKT3+ and OKT11+ cells (P less than 0.03), but not of other T cell fractions, significantly increased. In addition, no significant changes in the absolute numbers of T cell fractions were observed in this group of patients. Furthermore, no spontaneous variations in the T cell pool size occurred in untreated patients. TS maintenance therapy did not produce any further improvement in the size of overall T cells and T cell subsets but sustained percentage and absolute numbers of these cells during administration and the absolute number of T cells even after discontinuation of therapy. The TS-induced improvement in the T cell pool was not associated with any change in the size of circulating non-T lymphocytes and monocytes. In vitro phytohemagglutinin-induced interleukin-2 (IL-2) and gamma-interferon (IFN-gamma) synthesis was assessed in 11 patients (3 G1, 4 G2, and 4 G3). Although it was not statistically significant, a rise in IL-2 and IFN-gamma production was observed in TS-treated patients, but not in untreated controls. TS failed to exert any effect on the serum circulating levels of neopterin, type I and II IFN, beta-2 microglobulin (B2-M) and immunoglobulins (Ig). TS can thus improve defective T cell frequences and numbers and may modulate IL-2 and IFN-gamma production.

Immunologic profile in patients with Hodgkin's disease in complete remission.

Mononuclear cell subsets in peripheral blood, in vitro production of interleukin-2 (IL-2) and gamma interferon (IFN gamma), spontaneous cell-mediated cytotoxicity (SCMC) and circulating levels of Type I IFN, neopterin, beta-2 microglobulin (B2-M), immunoglobulins and complement fractions were studied in 33 patients with Hodgkin's disease (HD) in complete remission. The mean percentages, but not the absolute numbers, of T-lymphocytes expressing pan-T markers (OKT11, OKT3, ER, E-AET R) were significantly decreased compared with control values. Furthermore, patients showed a selective loss of OKT4+ cells, as well as increased percentages and numbers of Leu7+ and OKIa+ lymphocytes, and of OKM1+, LeuM2+, and LeuM3+ cells. OKT4+ cell depletion was a characteristic of patients with shorter time since beginning of remission as well as of those with nodular sclerosis (NS), mixed cellularity Hodgkin's disease (MC-HD), and systemic symptoms at diagnosis. Multifactorial statistical analysis carried out to investigate the effect of disease characteristics and the time since remission began on peripheral mononuclear blood cell (PMBC) subsets showed that histologic condition was the single best predictor of T-cell pool or OKT4+ cell subset size. Time since remission duration and other disease-related factors determined differences in the percentages, but not in the absolute numbers, of T-cell fractions. In addition, neither the disease features nor the time since remission duration determined significant differences in the absolute number of non-T-mononuclear cells in the various patient groups. Patients displayed decreased in vitro synthesis of IL-2 and IFN gamma. The values of SCMC, Type I IFN, neopterin, B2-M, immunoglobulins, and complement fractions did not differ greatly from those of controls.

[Importance of form in dental implantation]. / L'importanza della forma nell'impianto dentario.

Thirteen implantations have been made in the mandibular arches of 6 dogs. They consisted of commerical titanium blades and screws and of replicas of extracted dental roots variously shaped and made of titanium. All replicas and some of the commerical implantations were covered with pure aluminium using the plasmajet tecnique. Clinico-radiological, histopathological and microradiographical observation showed that only some of the replicas of dental roots give promising results.

Evaluation of hip arthroprostheses by means of body environment simulators.

Laboratory tests carried out by means of body environment simulators have proved to be very important for the evaluation of endoprostheses potentially useful for implantation. The present paper examines the problems connected with the design of such a simulator. The results obtained with an initial, very primitive simulator concerning the outlines of the phenomena of wear, corrosion, and friction and some wear properties of commercially available hip endoprostheses are presented. From these results, the motivation that led to the design of a more advanced simulator is presented. This latter simulator is also described.

[Dental implantations of ceramics-coated metals]. / Impianti dentari metallici rivestiti di ceramica

Recent studies and personal experience of the Authors in the field of dental implants have encountered the same fundamental problem which arises with orthopedic prosthesis procedures. The basic problem is that of adhesion between the bone tissue and the metal implant. Chrome-cobalt alloy, Tantalum and Titanium are the metals of most recent use. The Authors therefore proceeded to investigate the behaviour of alveolar bone tissue in the proximity of artificial teeth made of alloy (platinum-gold) covered with ceramic, as used in prosthetic dentistry. The experiment was carried out in a dog and a man. In the dog, two of its mandibular teeth were substituted with the same ceramic-gold implants: the first, a replica of natural tooth, was placed in the socket and held in place by metal splint and mandibular circumferential wirings. The other implant, without a replicated crown, was left free, within the alveolus, without contacting the near or opposing teeth. A solid smooth surfaced alumina device, shaped like a small cylinder, was implanted in the upper femoral epiphysis of the same animal.