Enhanced pulmonary epithelial replication and axial airway mucosubstance changes in F344 rats exposed short-term to mainstream cigarette smoke

Cigarette smoking is associated with respiratory diseases that may be caused by injury to specific pulmonary cells. The injury may manifest itself as site-specific enhanced cellular replication. In this study, rats were exposed either to mainstream cigarette smoke (CS; 250 mg total particulate matter/m(3)) or to filtered air (FA) for 6 h/day, 5 days/week, for 2 weeks. In one group, cells in S-phase were labeled over 7 days by bromodeoxyuridine (BrdU) released from implanted osmotic pumps (pump labeled), while another group received BrdU by injection 2 h prior to necropsy (pulse labeled). Morphometry showed that the type II epithelial BrdU labeling index (LI) was significantly elevated in the CS-exposed animals of both labeling groups. The axial airway and terminal bronchiolar LIs were enhanced by CS only in the pump-labeled group. In a third group (pulse labeled), 2 weeks of recovery following exposure to CS allowed a normalization in the type II LI. In the pump-labeled rats, the CS-induced elevation of the type II LI was greater than the LI elevation in conducting airways, suggesting that the parenchyma may have been injured more than the conducting airways. The terminal bronchiolar LI in the pump-labeled group, regardless of exposure, was significantly greater than the axial airway LI. Pump labeling, in contrast to pulse labeling, could therefore discern differences among replication rates of conducting airway epithelium in different regions of the lung. Mucosubstance (MS) within the axial airway epithelium was quantified by morphometry. The CS exposure did not increase the total number of MS-containing cells or the total number of axial airway epithelial cells, but there was a phenotype change in the MS cells. Neutral MS cells (periodic acid-Schiff-positive) were significantly decreased, while acid MS cells (alcian blue-positive) were slightly increased by CS exposure. Either cell replication and differentiation or differentiation alone may have changed the phenotype in the MS cell population.     

Regulation of complement activation by C-reactive protein.

C-reactive protein (CRP) is an acute-phase serum protein and a mediator of innate immunity. CRP binds to microbial polysaccharides and to ligands exposed on damaged cells. Binding of CRP to these substrates activates the classical complement pathway leading to their uptake by phagocytic cells. Complement activation by CRP is restricted to C1, C4, C2 and C3 with little consumption of C5-9. Surface bound CRP reduces deposition of and generation of C5b-9 by the alternative pathway and deposition of C3b and lysis by the lectin pathway. These activities of CRP are the result of recruitment of factor H resulting in regulation of C3b on bacteria or erythrocytes. Evidence is presented for direct binding of H to CRP. H binding to CRP or C3b immobilized on microtiter wells was demonstrated by ELISA. Attachment of CRP to a surface was required for H binding. H binding to CRP was not inhibited by EDTA or phosphocholine, which inhibit ligand binding, but was inhibited by a 13 amino acid CRP peptide. The peptide sequence was identical to the region of CRP that showed the best alignment to H binding peptides from Streptococcus pyogenes (M6) and Neisseria gonorrhoeae (Por1A). The results suggest that CRP bound to a surface provides secondary binding sites for H resulting in greater regulation of alternative pathway amplification and C5 convertases. Complement activation by CRP may help limit the inflammatory response by providing opsonization with minimal generation of C5a and C5b-9.     

Methods of measuring susceptibility of anaerobic bacteria to trovafloxacin,including quality control parameters

Three methods approved by the National Committee for Clinical Laboratory Standards for testing the susceptibility of anaerobic bacteria were used to evaluate the fluoroquinolone, trovafloxacin. The methods gave essentially comparable results with 126 anaerobes and with three quality control strains. A collaborative study defined the quality control range for trovafloxacin MICs. Trovafloxacin had good in vitro activity against the more common anaerobes (MIC 90 <- 2.0 (g/ml).Trovafloxacin (CP-99,219) is a fluoroquinolone with a broad spectrum of antibacterial activity (1–3). Its in vitro spectrum includes many anaerobic bacteria (4).The National Committee for Clinical Laboratory Standards (NCCLS) currently recommends three different methods for testing the susceptibility of anaerobic bacteria (5). The standard reference method is an agar dilution procedure using Wilkins-Chalgren agar. Two alternative methods are an agar dilution technique using Brucella blood agar and a microdilution procedure using a broth version of Wilkins-Chalgren medium. It is important to determine whether these three procedures actually produce identical test results with each antimicrobial agent likely to be tested against anaerobes.     

Diesel Exhaust Is Not a Pulmonary Carcinogen in CD-1 Mice Exposed under Conditions Carcinogenic to F344 Rats

Differences among laboratory animal species in the pulmonarycarcinogenicity of chronic inhalation exposure to diesel exhausthave raised several important interpretive issues. Under similarheavy exposure conditions, it is clear that diesel exhaust isa pulmonary carcinogen in rats, but not in Syrian hamsters.Previous reports give conflicting views of the response of mice,which is presently considered equivocal. This report describescarcinogenicity results from a bioassay of CD-1 mice conductedin parallel with a previously reported bioassay of F344 rats(Mauderly et al. (1987) Fundam. Appl. Toxicol. 9, 208–221).Exposure to whole diesel exhaust 7 hr/day, 5 days/week for 24months at soot concen trations of 0.35, 3.5, or 7.1 mg/m³ causedaccumulations of soot in mouse lungs similar to those in lungsof rats and, like the results from rats, did not significantlyaffect survival or body weight. In contrast to the dose-relatedneoplastic response of rats, however, the exposures of micedid not increase the incidence of lung neoplasms. This findingis consistent with other data showing that mice, as well asSyrian hamsters, differ from rats in their lung neoplastic andnonneoplastic responses to heavy, chronic inhalation exposureto diesel exhaust soot and several other particles. Althoughrodents serve as useful indicators of potential human carcinogenichazards, it is not yet clear which, if any, rodent species havelung neoplastic responses that are useful for quantitative predictionsof human lung cancer risk from chronic inhalation of poorlysoluble, respirable particles.     

Palmitoylation of myelin P0 protein is independent of its synthesis and parallels that of phospholipids

To determine whether the acyl chains modifying P0, the major protein of PNS myelin, turn over independently of the protein backbone, sciatic nerve slices from 10 to 65 day-old rats were incubated with a mixture of [3H]palmitic acid and [14C]amino acids, and proteins were analyzed by electrophoresis. Incorporation of [14C]amino acids into nerve P0 decreased approximately 10-fold between 10 and 65 days of age. In contrast, palmitoylation of P0, although maximal at 10 days-of age, decreased only 3-4-fold during the same period. In the same experiments, the incorporation of [3H]palmitate into the nerve and into various lipids classes diminished by a comparable extent (2.5-fold). Thus, if corrected by the uptake of the tritiated precursor, palmitoylation of P0 remains nearly constant throughout development, and it is therefore independent of protein synthesis. Preincubation of nerve slices with cycloheximide for one hour reduced the incorporation of [3H]palmitate into both P0 and phospholipids in a concentration-dependent manner. At 10 microM cycloheximide, palmitoylation of P0 was unaffected while its synthesis was still repressed, indicating that these events are uncoupled. The effect of cycloheximide on fatty acid uptake can be attributed to inhibition of the palmitoyl-CoA : lysophosphatidylcholine acyltransferase activity. Neither the distribution of palmitate between albumin and lipid membranes nor the activities of other lipid-metabolizing enzymes were affected by the inhibitor. In conclusion, these results indicate that P0 palmitoylation occurs mainly on the preexisting molecules, and it therefore constitutes a dynamic event.     

Chagas' disease in an obstetrical patient

We report a case of a parturient with documented chronic Chagas' disease with cardiac manifestations presenting for labor management and complicated by the need for emergent hysterectomy after delivery. Chagas' disease is a common human hematogenous trypanosomiasis in Central and South America which is now, because of population migration, appearing in the USA. This disease predominantly affects the heart and the gastrointestinal system. This report discusses the parasite, the acute and chronic phases of Chagas' disease and highlights its medical implications, including maternal-fetal transfer of Trypanosoma cruzi.     

Further studies of the turnover of dog antithrombin III. Study of 131I-labelled antithrombin protease complexes

Fresh plasma containing 131I-antithrombin III (*I-AT) was coagulated and incubated at 37 degrees C for 2 hr. A "complex peak," separated on heparin-agarose contained AT and *I-AT antigen but no heparin cofactor activity. Crossed immunoelectrophoresis showed only AT complexes. SDS PAGE showed 80% of the *I-AT in a major band (approximately 80,000 daltons), 15% in a minor band (approximately 100,000 daltons) and the rest in trace bands (approximately 60,000 and/or 115,000 daltons). Ammonia treatment of the complex peak released alpha-thrombin. After i.v. injection 80% of the complexed *I-AT, chiefly as the major band, left the plasma with t 1/2 approximately 15 min and was almost immediately catabolized to low molecular weight breakdown products. A major catabolic site was the liver. A simple kinetic model describes the findings approximately.     

Pharmaceutical service differences between teaching and community hospitals

The purpose of this study was to inventory the highly specialized units maintained in teaching hospitals and compare and contrast the scope and level of pharmaceutical services provided in teaching and similar-size community hospitals. In 1989, a 30-item questionnaire was mailed to a sample of 120 teaching hospitals. The scope and level of services provided was compared with similar size hospitals in the 1989 American Society of Hospital Pharmacists' survey of hospital-based pharmaceutical services. Teaching hospitals maintain more licensed and occupied beds, are more likely to be a member of a nonprofit multisystem organization, maintain many specialized care units and high speed transportation vehicles, exercise more control over specialized drugs and products, provide a broader array of pharmacy services to ambulatory patient populations, offer a more extensive and broader array of clinical services, maintain more extensive drug information resources, exercise more comprehensive formulary management initiatives, engage in broader diversified service initiatives, and generate 50% more annual pharmacy costs per occupied bed than do similar-sized community hospitals. Teaching hospitals are complex organizations that provide care to patients who require higher levels of pharmaceutical services than those provided in similar-sized community hospitals.     

Acetaminophen-induced cytotoxicity in cultured mouse hepatocytes: effects of Ca(2+)-endonuclease, DNA repair, and glutathione depletion inhibitors on DNA fragmentation and cell death.

Hepatotoxic alkylation of mouse liver cells by acetaminophen is characterized by an early loss of ion regulation, accumulation of Ca2+ in the nucleus, and fragmentation of DNA in vitro and in vivo. Acetaminophen-induced DNA cleavage is accompanied by the formation of a "ladder" of DNA fragments characteristic of Ca(2+)-mediated endonuclease activation. These events unfold well in advance of cytotoxicity and the development of necrosis. The present study utilized cultured mouse hepatocytes and mechanistic probes to test whether DNA fragmentation and cell death might be related in a "cause-and-effect" manner. Cells were isolated by collagenase perfusion, cultured in Williams' E medium for 22-26 hr, and exposed to acetaminophen. Aurintricarboxylic acid, a general Ca(2+)-endonuclease inhibitor, and EGTA, a chelator of Ca2+ required for endonuclease activation, significantly decreased DNA fragmentation at 6 and 12 hr and virtually abolished cytotoxicity. N-Acetylcysteine also eliminated DNA fragmentation and cytotoxicity. 3-Aminobenzamide, an inhibitor of poly(ADP-ribose) polymerase-stimulated DNA repair, failed to alter the amount of DNA fragmentation at 6 hr but substantially increased acetaminophen cytotoxicity in hepatocytes at 12 hr. With the exception of when DNA repair was inhibited by 3-aminobenzamide, Ca2+ accumulation in the nucleus, DNA fragmentation, and hepatocyte death varied consistently and predictably with one another. Collectively, these findings suggest that unrepaired damage to DNA contributes to acetaminophen-induced cell death in vivo and may play a role in necrosis in vivo.