Effect of fentanyl-oxygen anesthesia during cardiac surgery on serum thyroid hormones

Twenty-five euthyroid patients who underwent cardiac surgery with fentanyl-oxygen anesthesia were studied. The authors confirm that some thyroid hormones undoubtedly take part in a non-specific pool of reactions caused by surgical stress. For one or more days, all the patients had total triiodothyronine (TT3) and free triiodothyronine (FT3) levels clearly below the normal values, with a parallel increase in reverse triiodothyronine (rT3, biologically inactive). Changes in total (TT4) and free thyroxine (FT4), although significant, were smaller and hard to interpret. The most important changes occurred on the first postoperative day. Of seven patients who before the operation had a TT3 value below the lower normal limit, six had at discharge a mean TT3 level significantly above it. Serum TT3 concentrations could be a reliable prognostic index. High-dose fentanyl anesthesia probably does not affect thyroid hormone response to surgical stress. To date, the mechanisms which cause reduction of serum triiodothyronine have not been fully discovered and it is not known for certain whether this reduction is beneficial to the human organism.     

Asbestos Exposure of Building Maintenance Personnel

The exposures of building maintenance personnel and occupants to airborne asbestos fibers, and the effects of operations and maintenance programs on those exposures, continue to be an important public health issue. The subject of this investigation was a large metropolitan county with numerous public buildings which routinely conducted air sampling for asbestos. A total of 302 personal air samples in nine task categories collected during maintenance worker activities in proximity to asbestos-containing materials were analyzed; 102 environmental air samples in four task categories were also analyzed. The arithmetic means of the 8-hr time weighted average exposures for personal sampling for each task category were all below the Occupational Safety and Health Administration permissible exposure level of 0.1 fibers (f)/cc > 5 μm. The highest mean 8-hr time weighted average exposure was 0.030 f/cc > 5 μm for ceiling tile replacement. The maximum asbestos concentration during sample collection for environmental samples was 0.027 f/cc > 5 μm. All asbestos-related maintenance work was done within the framework of an Operations and Maintenance Program (OMP) which utilized both personal protective equipment and controls against fiber release/dispersion. Results are presented in association with specific OMP procedures or controls. These results support the effectiveness of using Operations and Maintenance Programs to manage asbestos in buildings without incurring unacceptable risk to maintenance workers performing maintenance tasks.     

First year's experience of the MAClinical Computer Workstations Project

We have an installed base of MAClinical workstations available on hospital wards, which have been used for patient care, education, and research 24 hours a day for the past year. We began with eight machines in the hospital but now have distributed ten more machines to faculty. We have recently increased the programming staff so we can develop more software. The machines and their installation were costly, but have already proven useful for teaching and patient care. Plans for the second and third years of the MAClinical project include workstations for the faculty coordinators of clinical clerkships and expansion of workstations to affiliated hospitals where our students and residents rotate. Software will be expanded to include patient simulations and expert consultations. Medical practice, research, and teaching in the future will need to make more use of information technology. It is not yet clear exactly how and where computers will best serve clinical medicine, but the teaching hospital can be both a laboratory for developing applications and a school for training physicians to use them.     

Asbestosis and small cell lung cancer in a clutch refabricator

OBJECTIVES: To present a case of asbestosis and small cell lung cancer caused by asbestos in a clutch refabricator. METHODS: Exposed surfaces of used clutches similar to those refabricated in the worker's workplace were rinsed, and the filtrate analysed by analytical transmission electron microscopy. Tissue samples were also analysed by this technique. RESULTS: Numerous chrysotile fibres of respirable dimensions and sufficient length to form ferruginous bodies (FBs) were detected from rinsed filtrates of the clutch. Bronchoalveolar lavage fluid contained many FBs, characteristic of asbestos bodies. Necropsy lung tissue showed grade 4 asbestosis and a small cell carcinoma in the right pulmonary hilum. Tissue analysis by light and analytical electron microscopy showed tissue burdens of coated and uncoated asbestos fibres greatly exceeding reported environmental concentrations (3810 FBs/g dry weight and 2,080,000 structures > or = 0.5 micron/g dry weight respectively). 72% Of the cores were identified as chrysotile. CONCLUSIONS: Clutch refabrication may lead to exposure to asbestos of sufficient magnitude to cause asbestosis and lung cancer.

 

     

Clonal karyotypic abnormalities in gynecomastia

Gynecomastia is a benign condition that frequently occurs in the male breast gland; however, the cytogenetic data on this entity are very limited. To our knowledge, three cases have been reported in the literature, and the only one with an abnormal karyotype had a concomitant breast carcinoma. In this study we report clonal chromosomal alterations in a gynecomastia sample without any signs of adjacent malignant tissue. The nonrandom abnormalities observed were a deletion of 12p, monosomies of chromosomes 9, 17, 19, and 20, and the presence of a marker chromosome. Most of these alterations have been previously described in the literature in other breast lesions, including benign and malignant (male and female) tumors, indicating their recurrence and nonrandomness in abnormal processes of the mammary gland.     

Molecular and neurochemical evaluation of the effects of etizolam on GABAA receptors under normal and stress conditions

The thienobenzodiazepine derivative etizolam (CAS 40054-69-1, 6-(o-chlorophenyl)-8-ethyl-1-methyl-4H-s-triazolo-(3,4-c)thienol(1 ,4) diazepine) is a potent anxiolytic with a pharmacological profile similar to that of classical benzodiazepines. In order to rationalize the therapeutic use of etizolam, its pharmacodynamics properties on GABAA receptors were investigated by a comparative study with other ligands on human recombinant GABAA as well as rat brain native receptors. Etizolam inhibited in a concentration-dependent manner [3H]flunitrazepam (CAS 1622-62-4) binding to rat cortical membranes, with an affinity of 4.5 nmol/l greater than that of alprazolam (CAS 28981-97-7) (7.9 nmol/l). Ethizolam enhanced GABA-induced Cl- currents in oocytes expressing human cloned GABAA receptors. With alpha 1 beta 2 gamma 2S subunit combination, etizolam produced a 73% increase in GABA-induced currents with an EC50 of 92 nmol/l. At the same receptor type, alprazolam showed a higher degree of potentiation and potency (98%, EC50 56 nmol/l). At alpha 2 beta 2 gamma 2S or alpha 3 beta 2 gamma 2S subunit constructs, the effects of etizolam were similar to those of alprazolam. Flumazenil (CAS 78755-81-4) completely blocked both etizolam and alprazolam effects on GABA-induced currents. Etizolam, administered i.p., was uneffective in changing ex vivo t-[35S]butylbicyclophosphorothionate ([35S]-TBPS) binding to rat cerebral cortex, whereas alprazolam and abecarnil (CAS 111841-85-1) significantly reduced this parameter. However, etizolam similarly to abecarnil and alprazolam, antagonized isoniazid-induced increase (61%) in [35S]-TBPS binding to rat cortical membranes. Further, etizolam inhibited in a dose-dependent manner basal acetylcholine release from both hippocampus and prefrontal cortex, and reversed foot-shock-induced increase of basal acetylcholine release to a control level. Altogether, these results suggest that etizolam may have a reduced intrinsic activity, at least at specific subpopulations of GABAA receptors. This property, together with the pharmacokinetic indication of a short-acting drug, may characterize etizolam as a ligand endowed with less side-effects typical of full agonits such as diazepam (CAS 439-14-5) and alprazolam. Finally, given its marked efficacy under conditions of GABAergic deficit, etizolam may represent a possible drug of choice with reduced liability to produce tolerance and dependence after long-term treatment of anxiety and stress syndromes.