Scanning electron microscopy of normoxic and hyperoxic hyperbaric exposed lungs

Lungs from adult guinea pigs exposed to 1 ATA He-O2 with 200 mm Hg PO2 and 20 ATA He-O2 with 200, 400, and 600 mm Hg PO2 were studied with scanning electron microscopy. The appearance of normal alveoli is described. Even before pulmonary O2 toxicity became symptomatic, subtle changes occurred in the alveoli, such as an increase in macrophages and a marked increase in length of alveolar type-II cell microvilli. These changes occurred in animals exposed to 400 mm Hg PO2, heretofore considered below toxic levels. With increased toxic involvement, the number of alveolar type-II cells increased. A thick layer of material appeared in some of the alveoli, obscuring the Kohns pores and type-I and -II cell surfaces. The alveolar-capillary network with underlying erythrocytes was no longer observable. Lungs with the greatest toxic involvement possessed large numbers of macrophages encompassed by a fibrin-like matrix. The alveolar walls were broken down in many instances, and the alveoli were no longer discrete units but took on the appearance of an amorphous mass of lung tissue.     

Impact of first-responder defibrillation in an urban emergency medical services system

OBJECTIVE: To evaluate the impact of adding first-responder defibrillation by fire-fighters to an existing advanced life-support emergency medical services system. DESIGN: Nonrandomized, controlled clinical trial with periodic crossover. SETTING: Memphis, Tenn, a city of 610,337 people, which is served by a fire department-based emergency medical services system. All city ambulances provide advanced life support. PATIENTS: Adult victims of out-of-hospital cardiac arrest due to heart disease. INTERVENTION: Twenty of 40 participating engine companies were equipped with an automated external defibrillator and ordered to apply it immediately in all cases of cardiac arrest. The other 20 companies were ordered to start cardiopulmonary resuscitation (CPR) immediately and wait for paramedics to arrive. Every 75 days, group roles were reversed. Care otherwise proceeded according to 1986 American Heart Association guidelines. MAIN OUTCOME MEASURES: Return of spontaneous circulation in the field, survival to hospital admission, survival to hospital discharge, and neurological status at discharge. RESULTS: During the 39-month study interval, 879 patients were treated by a project engine company. Four hundred thirty-one (49%) of these were found in ventricular fibrillation. Bystander CPR was started in only 12% of cases. Overall, firefighters reached the scene a mean of 2.5 minutes faster than simultaneously dispatched paramedics. Although our automated external defibrillators proved to be reliable and efficacious for terminating ventricular fibrillation and pulseless ventricular tachycardia, patients treated by an automated external defibrillator-equipped engine company were no more likely than CPR-treated controls to be resuscitated (32% vs 34%, respectively), to survive to hospital admission (31% vs 29%), or to survive to hospital discharge (14% vs 10%). Neurological outcomes were also similar in the two treatment groups. CONCLUSIONS: In a fast-response, urban emergency medical services system served by paramedics, the impact of adding first-responder defibrillation appears to be small. Early defibrillation alone cannot overcome low community rates of bystander CPR. Careful attention to every link in the "chain of survival" is needed to achieve optimal rates of survival after cardiac arrest.     

Association between low contents of dopamine and serotonin in the nucleus accumbens and high alcohol preference

The contents of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) were determined in the nucleus accumbens (ACB), frontal cortex (FR), anterior striatum (AST), and hippocampus (HIP) of adult male rats from the F2 generation of P x NP intercrosses. Rats were tested for their alcohol preference and were divided into two groups, depending on their alcohol intake. Rats in the high drinking group (n = 11) had ethanol intakes > 5g/kg/day, whereas the low drinking group (n = 15) had values < 1 g/kg/day. The content of DA in the ACB was lower (p < 0.001) in the high alcohol drinking group (46 +/- 2 pmol/mg tissue) than in the low intake rats (61 +/- 3 pmol/mg tissue). However, the contents of DOPAC and HVA in the ACB were similar for both groups. There were no differences between the two groups in the contents of DA in the FR or AST. The content of 5-HT in the ACB was lower (p < 0.05) in high alcohol drinking rats (6.3 +/- 0.3 pmol/mg tissue) than in the low intake group (7.0 +/- 0.2 pmol/mg tissue). The content of 5-HIAA in the ACB of the high intake rats was also lower than the level for the low drinking rats. There were no differences in the contents of 5-HT or 5-HIAA in the FR, HIP, and AST between the two groups. The results confirm a phenotypic association between abnormal DA and 5-HT systems projecting to the ACB and high alcohol drinking behavior in the P line of rats.     

Quantitative three-dimensional assessment of face-lift with an optical facial surface scanner

We have established a strain of transgenic mice in which the HLA-DRA gene was integrated into the X-chromosome and the xenogeneic mixed isotype molecule, DR alpha E beta b, was expressed in a cell type-specific manner, although the transgenic DRA gene contained only 268 base pairs of the 5'-flanking region. The DR alpha E beta b molecules expressed in the transgenic mice functioned as major histocompatibility complex (MHC) class II to select T-cell repertoire, and to stimulate mixed lymphocyte reaction. In female transgenic mice homozygous for HLA-DRA (DR alpha-B6-F-homo) and male transgenic mice (DR alpha-B6-M), DR alpha E beta b molecules were expressed in almost all of the MHC class II Ab-positive cells. In contrast, the expression of DR alpha E beta b molecules in female transgenic mice hemizygous for HLA-DRA (DR alpha-B6-F-hemi) was found only in part of the Ab positive cells, and the proportion of cells expressing the DR alpha E beta b molecules varied due to random inactivation of one of the X-chromosomes. Clonal deletions of the T cells and mature thymocytes bearing Tcrb-V5 and Tcrb-V11, which are eliminated from the peripheral repertoire in mice expressing self-superantigen and MHC class II E molecules, were incomplete in DR alpha-B6-F-hemi as compared with those in DR alpha-B6-F-homo, and were correlated with the proportion of DR alpha E beta b-positive spleen cells. These observations suggested that the number of bone marrow-derived cells expressing DR alpha E beta b molecules was critical for clonal deletions of Tcrb-V5+ and Tcrb-V11+ T cells in the thymus.