Thyrotrophin-releasing hormone decreases feeding and increases body temperature, activity and oxygen consumption in Siberian hamsters

Thyrotrophin-releasing hormone (TRH) is known to play an important role in the control of food intake and energy metabolism in addition to its actions on the pituitary-thyroid axis. We have previously shown that central administration of TRH decreases food intake in Siberian hamsters. This species is being increasingly used as a physiological rodent model in which to understand hypothalamic control of long-term changes in energy balance because it accumulates fat reserves in long summer photoperiods, and decreases food intake and body weight when exposed to short winter photoperiods. The objectives of our study in Siberian hamsters were: (i) to investigate whether peripheral administration of TRH would mimic the effects of central administration of TRH on food intake and whether these effects would differ dependent upon the ambient photoperiod; (ii) to determine whether TRH would have an effect on energy expenditure; and (iii) to investigate the potential sites of action of TRH. Both peripheral (5-50 mg/kg body weight; i.p.) and central (0.5 microg/ml; i.c.v.) administration of TRH decreased food intake, and increased locomotor activity, body temperature and oxygen consumption in the Siberian hamster, with a rapid onset and short duration of action. Systemic treatment with TRH was equally effective in suppressing feeding regardless of ambient photoperiod. The acute effects of TRH are likely to be centrally mediated and independent of its role in the control of the production of thyroid hormones. We conclude that TRH functions to promote a catabolic energetic state by co-ordinating acute central and chronic peripheral (thyroid-mediated) function.

Dangerous liaison: sexually transmitted allergic reaction to Brazil nuts

Brazil nuts are the second most frequent cause of nut allergy in the United Kingdom. We report the case of a 20-year-old woman with documented Brazil nut allergy who developed widespread urticaria and mild dyspnea after intercourse with her boyfriend who had earlier consumed Brazil nuts. Skin prick testing with the boyfriend's semen after Brazil nut consumption confirmed significant reactivity whereas a sample before nut consumption was negative. We believe this to be the first case of a sexually transmitted allergic reaction.

Infections of the subcutis and skin of dogs caused by rapidly growing mycobacteria

Nine dogs with panniculitis due to rapidly growing mycobacteria (RGM) were examined over 17 years. Dogs were two to 15 years; five were male, four were female. All were obese or in good condition. Antecedent injury, typically a dog bite or vehicular trauma, could be identified in some patients, while one bitch had hyperadrenocorticism. Infections involved different locations, although the cervicothoracic region, dorsum or flank were most often affected. Patients were systemically well, apart from one dog with pyrexia and two with pain or lameness. Cytology demonstrated pyogranulomatous inflammation, but in only one case was it possible to see acid-fast bacilli (AFB) in smears. Histology demonstrated chronic active pyogranulomatous panniculitis and dermatitis; AFB could be detected in only four specimens. Culture of aspirates or resected tissues demonstrated RGM in all cases, comprising six Mycobacterium smegmatis group and three Mycobacterium fortuitum group isolates. Resection of infected tissues, perioperative injectable antimicrobials and long courses of oral antimicrobials chosen according to susceptibility data generally effected a cure, although some cases recurred.

What perioperative and emerging workforce nurses want in a manager

The world is experiencing a critical shortage of RNs. As the number of nurses decreases, it is unclear how already vulnerable specialty areas, such as perioperative nursing, will be affected by the emerging workforce's career decisions. This descriptive, comparative study explores perioperative nurses' and nursing students' perceptions of the top 10 characteristics desired in a manager. Even with 70% congruency, significant differences were found in how nurses and students ranked the traits they valued. This study highlights the traits managers need to transform new graduate nurses into satisfied, productive members of the perioperative team.

Development of a standardized nomenclature for bronchoscopy of the respiratory system of harbor porpoises (Phocoena phocoena)

Respiratory disease is common in captive and wild cetaceans. Bronchoscopy may permit early diagnosis of respiratory disease in dolphins and porpoises. Refinement of cetacean bronchoscopy requires development of a nomenclature system to facilitate description of the anatomic site at which lesions occur. A standard bronchoscopic nomenclature also permits serial evaluations of lesions and enhances communication between veterinarians. In this project, we adapted the bronchoscopic nomenclature devised by Amis and McKiernan for the dog and horse to the harbor porpoise (Phocoena phocoena). Silastic and air-dried models of the bronchial tree of the harbor porpoise were made to illustrate the anatomy and devise the nomenclature. Bronchial anatomy was consistent among the four porpoise lungs studied. The Amis and McKiernan nomenclature was readily adaptable to the harbor porpoise lung with minor modifications and may be useful for cetacean bronchoscopy.

Helicobacter pylori induces apoptosis in human epithelial gastric cells by stress activated protein kinase pathway

BACKGROUND

The pathway by which Helicobacter pylori induces apoptosis in gastric epithelial cells is not known. The aim of this study was to determine whether H. pylori-induced apoptosis is associated with SAPK/JNK activity in human gastric cancer KATO III cells.

MATERIALS AND METHODS

H. pylori VacA toxin positive strain was incubated with KATO III cells for 0.5, 1, 2 or 24 hours. The SAPK/JNK protein was harvested from the KATO III cell lysate by precipitation with a C-jun fusion protein and its activity was measured by C-jun phosphorylation utilizing transblotting and phosphoserine antibody. Cellular apoptosis was demonstrated by DNA fragmentation. In addition, cell growth in coculture with H. pylori was determined over 72 hours.

RESULTS

H. pylori significantly stimulated SAPK/JNK activity in KATO III cells with a peak at the 0.5 hour time point (3.6-fold vs. control, p <.05), but a return to basal levels by 2 hours. In addition, significant DNA fragmentation was observed after 24 hours in these cells but not in the control KATO III cells. Cell growth was inhibited in a dose dependent fashion in coculture with H. pylori.

CONCLUSION

These results show that H. pylori triggers an increase in apoptosis in KATO III cells as reflected by DNA fragmentation. This effect was preceded and correlated with an increase in SAPK/JNK activity suggesting that the H. pylori-induced apoptosis in human gastric epithelial cells may be mediated by the SAPK/JNK pathway.

Mechanisms of cocaine hydrolysis and metabolism in vitro and in vivo: a clarification

There is confusion in the literature concerning the mechanisms by which the cocaine hydrolysis product, benzoylecgonine (BE), is formed in vitro and in vivo. Some authors assume that all BE is formed nonenzymatically. This review summarizes evidence that both enzymatic and nonenzymatic mechanisms exist. In vitro BE is produced exclusively by hydrolysis at alkaline pH, as esterases present in blood or serum do not catalyze formation of BE. In vivo BE is formed both nonenzymatically as well as through the action of esterases found in a number of tissues including hepatocytes. The enzymatic mechanism is the predominant one operating in vivo.

Evaluation of the BACTEC MGIT 960 system for the recovery of mycobacteria

We evaluated the BACTEC MGIT 960 system, which is a fully automated, non-invasive, continuous monitoring system for the growth and detection of mycobacteria. Including respiratory and other specimens, 1,742 specimens were processed and inoculated into the BACTEC MGIT 960 and the BACTEC 460 TB Systems, as well as onto Lowenstein-Jensen (L-J) media. A total of 104 isolates of mycobacteria were recovered from all culture systems. This included Mycobacterium tuberculosis complex, Mycobacterium avium-intracellulare (MAI) complex and other mycobacteria (MOTT). The isolation rates for M. tuberculosis complex and MAI complex were comparable for the BACTEC 460 (54.8% and 13.5%) and the BACTEC MGIT 960 (51.9% and 13.5%). The overall isolation rate was less for BACTEC MGIT 960 (76.9%) which was due to lesser number of MOTT isolates recovered from this system. The mean times to detection (TTD) for all mycobacteria were 9.3 days for the BACTEC MGIT, 14.6 days for the BACTEC 460 and 21.6 days for L-J. A significant difference was observed when TTD was tested in relation to degree of positivity in smears, with the BACTEC MGIT maintaining the short TTD even with less number of bacilli in the smear. The contamination rates were, 6.4% for BACTEC MGIT, 2.9% for BACTEC 460 and 12.1% for L-J medium. The BACTEC MGIT 960 system shows performances comparable to the BACTEC 460 and seems to be a dependable, user friendly system.

Angiocentric recruitment of lymphocytes into the lung after the intrabronchial instillation of antigen

The pathogenesis of acute lymphocytic inflammation in the lower respiratory tract appears to involve the recruitment of lymphocytes out of the blood stream and into the extravascular lung tissue. To investigate the membrane molecules regulating this process, we used the intrabronchial instillation of cellular antigen to trigger lymphocyte recruitment into the lower respiratory tract. Sheep presensitized 6 to 10 weeks earlier at a remote site were intrabronchially challenged with 1-5 x 10(7) cells from a B lymphoblastoid cell line. The cells were instilled into a subsegmental bronchus through a bronchial catheter. The stimulated and contralateral control segments were studied at a peak of inflammation, approximately 72 hours after antigen stimulation. Gross and microscopic studies of the stimulated segment demonstrated localized inflammation characterized by the perivascular infiltration of lymphocytes. In contrast, control areas of the lung demonstrated only scattered perivascular lymphocytes. Immunohistochemistry of the stimulated lung showed that the majority of these perivascular cells were CD3+ CD4+ lymphocytes. The T lymphocytes expressed high levels of the cell adhesion molecules beta 1 integrin and LFA-1, but low levels of the L-selectin membrane molecule. Immunohistochemistry of the endothelial cells associated with the lymphocyte infiltrates demonstrated intense staining of the ICAM-1, and beta 1 integrin adhesion molecules. Electron microscopic studies of the endothelial cells in the antigen stimulated areas of the lung confirmed morphologic changes consistent with endothelialitis. These results suggest that the intrabronchial instillation of cellular antigen stimulates an angiocentric T-cell infiltration regulated by activated pulmonary endothelial cells. The histologic and morphologic findings are remarkably similar to those observed during acute lung transplant rejection.

Setting standards of practice in therapeutic drug monitoring and clinical toxicology: a North American view

Standards for therapeutic drug monitoring (TDM) must address the factors required for a valid TDM result. These are that the test be ordered with an appropriate indication, samples be obtained at the appropriate time, analysis be precise and accurate, and the result be interpreted and used correctly. General indications for ordering drug concentrations are to assess patient compliance, lack of response, adverse effects, initial or new baseline concentration after steady state has been achieved, and drug interactions. In establishing standards for clinical toxicology testing, the following points need to be considered: relatively few drugs will be involved in the majority of overdoses in a given location, the majority of drug overdoses and poisonings are treated symptomatically and supportively, and there are a relatively small number of drugs the testing of which may provide useful information in the emergency setting. An effective toxicology screen can be designed by first developing a list of candidate drugs that have antidotes, require specific treatment, are frequently encountered, or have a delayed onset of toxicity. Once such a list is in hand, it can be further evaluated to determine whether qualitative or quantitative testing is most appropriate and if rapid, convenient methods of analysis are available.

A group motivational treatment for chemical dependency

Patient "motivation" has been implicated as a critical component in addiction treatment outcomes. To date, treatments utilizing motivational elements have been conducted as individual interventions. We describe the development of a Group Motivational Intervention (GMI), a four-session, manual-driven group approach that employs key hypothesized motivational elements. These include the six motivational elements derived by Miller and Sanchez (1994) from successful alcoholism treatments, described with the acronym, FRAMES (feedback, responsibility, advice, menu of options, empathy, and self-efficacy). GMI is additionally informed by concepts derived from "self-determination theory" (Deci & Ryan, 1985), concerned with understanding motivation as either internal/autonomous or external/controlled. Evidence indicates that people will value and persist longer in behaviors that they perceive as autonomously motivated. GMI techniques utilize the interpersonal factors found to be autonomy-supportive in self-determination theory. Preliminary results from a randomized clinical trial suggest that key motivational processes are affected by GMI: patients perceive the GMI environment and group leader as significantly more "autonomy supportive" than treatment "as usual."

21st-century leadership in nursing education: the need for trifocals

In this qualitative study, deans of top-ranked graduate nursing schools were interviewed to examine how they are approaching leadership issues into the next century. Discussion focused on managing change, handling problems, communication/leadership styles, models of governance, research productivity, and expectations of faculty. The picture that emerged suggested that deans must be able to see objects and events from different perspectives, analogous to wearing trifocal eyeglasses. Deans described current roles, which were labeled as Director, Sensor, and Negotiator. However, future roles will require a different set of skills and competencies. Deans described these roles as Consensus Builder, Risk Taker, and Interactive Empowerer. Deans will need to react based on multiple points of vision and accommodate rapidly to maintain excellence in all areas of the mission.

Mite fauna in the home and sensitivity to house-dust and storage mites

In search of potential new indoor allergen sources, all mites in dust from homes of 55 asthmatic children living in three climatic regions in Sweden were counted and identified by light microscope. Antibodies of the IgE class against three house-dust mites and three storage mites were measured in corresponding serum samples. Mites were found in all but two homes from the northernmost area, where levels also were lower than in the other regions. The highest mite densities were most often found in bedrooms (50%) and living rooms (40%). Mite density was increased in homes with high humidity and was higher in bungalows than in flats. House-dust mites predominated in the south and storage mites in the east central area, particularly in kitchens and bathrooms. Mite-density and IgE-antibody levels against house-dust mites were significantly associated. The same association applied to storage mites. Other species numbered around 100 mites/g dust in some homes. Microscopy helps to identify potentially important mites. Analysing home dust only for house-dust mites will underestimate mite exposure. Storage mites may be as relevant to sensitivity as house-dust mites. As other species occasionally were found in high numbers, their relevance should also be assessed.

Interactions between growth factors and gap junctional communication in developing systems

In the vertebrate limb bud fibroblast growth factor (FGF) 4 secreted by cells of the posterior apical ectodermal ridge controls digit pattern, which is directed by polarizing cells in the posterior mesenchyme at the tip of the bud. FGF4 also controls the expression of gap junctions in the limb. Both chick and mouse limb bud mesenchyme express connexin 32 (Cx32; beta 1) and Cx43 (alpha 1), although not in the same gap junction plaques. Quantitative analysis reveals two gradients of gap junctions: from posterior to anterior in the subapical mesenchyme and from distal to proximal along the bud. The highest gap junction density is associated with the polarizing region. Micromass cultures of chick and mouse posterior and anterior mesenchyme cells were used to assess the ability of FGF4 to modulate gap junctional communication. Posterior mesenchyme (polarizing region) cells express a population of gap junctions that are highly sensitive to FGF4, whereas gap junctions between anterior mesenchyme cells are completely insensitive to FGF4. FGF4 doubles gap junction density, intercellular communication and the polarizing capacity of posterior mesenchyme cells, restoring polarizing capacity to in vivo levels. We conclude that gap junctional communication and polarizing capacity are intimately linked. Interactions between signalling molecules and junctional communication may play an important role in controlling development.

Environmental assessment of Dermatophagoides mite-allergen levels in Sweden should include Der m 1

The major allergen of Dermatophagoides microceras, Der m 1, as well as the allergens of D. pteronyssinus and D. farinae, Der p 1 and Der f 1, were analyzed in the homes of 111 asthmatic children in three climatic regions in Sweden. The numbers and species of mites were determined by microscopy, and circulating IgE antibodies against mites were measured. Der f 1 was the predominant house-dust-mite (HDM) allergen, Der p 1 the least often found, and Der m 1 represented 31% of the allergen load. However, in the Linköping area, Der m 1 was the major HDM allergen (58%). Mite counts and allergen levels correlated well. Current exposure to HDM allergens at home was associated with the serum IgE antibody response to HDM in the children with no threshold level. Of the children with IgE antibodies against HDM, 67% reacted to all three mites. Mite sensitization rates were marginally increased (7%) by the addition of IgE analysis of D. microceras to the routine analysis of IgE antibodies against D. pteronyssinus and D. farinae. Thus, Der m 1 may be an important HDM allergen and should be considered when HDM exposure data are assessed in areas with a climate like that of Sweden.

Standards of laboratory practice: antiepileptic drug monitoring

Discussion and development of standards for appropriate monitoring led to the following key recommendations for ordering, sampling, and analyzing antiepileptic drugs: Monitoring should usually be done on trough specimens after steady-state has been reached and always with an appropriate medical indication; non-steady-state concentrations may be indicated in selected situations. Monitoring of free phenytoin and free valproic acid is indicated in specific situations and should be done in serum. The metabolite of primidone, phenobarbital, should be measured concurrently with parent drug, but the active metabolite of carbamazepine does not need to be monitored unless the patient is exhibiting an unusual toxic response that cannot be otherwise explained. Assays used for antiepileptic drug monitoring should display a long-term CV of &lt;10% and preferably &lt;5%. Subtherapeutic and supratherapeutic drug concentrations should be investigated on a regular basis as part of a quality assurance process.

Standards of laboratory practice: antiepileptic drug monitoring. National Academy of Clinical Biochemistry

Discussion and development of standards for appropriate monitoring led to the following key recommendations for ordering, sampling, and analyzing antiepileptic drugs: Monitoring should usually be done on trough specimens after steady-state has been reached and always with an appropriate medical indication; non-steady-state concentrations may be indicated in selected situations. Monitoring of free phenytoin and free valproic acid is indicated in specific situations and should be done in serum. The metabolite of primidone, phenobarbital, should be measured concurrently with parent drug, but the active metabolite of carbamazepine does not need to be monitored unless the patient is exhibiting an unusual toxic response that cannot be otherwise explained. Assays used for antiepileptic drug monitoring should display a long-term CV of <10% and preferably <5%. Subtherapeutic and supratherapeutic drug concentrations should be investigated on a regular basis as part of a quality assurance process.

Homology modelling of two subtilisin-like proteases from the hyperthermophilic archaea Pyrococcus furiosus and Thermococcus stetteri

The hyperthermophilic archaeon Pyrococcus furiosus produces an extracellular, glycosylated hyperthermostable subtilisin-like serine protease, termed pyrolysin (Voorhorst,W.G.B., Eggen,R.I.L., Geerling,A.C.M., Platteeuw,C., Siezen,R.J. and de Vos,W.M. (1996) J. Biol. Chem., 271, 20426-20431). Based on the pyrolysin coding sequence, a pyrolysin-like gene fragment was cloned and characterized from the extreme thermophilic archaeon Thermococcus stetteri. Like pyrolysin, the deduced sequence of this serine protease, designated stetterlysin, contains a catalytic domain with high homology with other subtilases, allowing homology modelling starting from known crystal structures. Comparison of the predicted three-dimensional models of the catalytic domain of stetterlysin and pyrolysin with the crystal structure of subtilases from mesophilic and thermophilic origin, i.e. subtilisin BPN' and thermitase, and the homology model of subtilisin S41 from psychrophilic origin, led to the identification of features that could be related to protein stabilization. Higher thermostability was found to be correlated with an increased number of residues involved in pairs and networks of charge-charge and aromatic-aromatic interactions. These highly thermostable proteases have several extra surface loops and inserts with a relatively high frequency of aromatic residues and Asn residues. The latter are often present in putative N-glycosylation sites. Results from modelling of known substrates in the substrate-binding region support the broad substrate range and the autocatalytic activation previously suggested for pyrolysin.

Effect of anaerobiosis on cysteine protease regulation during the embryonic-larval transition in

Hydrated encysted embryos of the brine shrimp Artemia franciscana have the ability to withstand years in anaerobic sea water using metabolic strategies that enable them to inactivate all cell metabolic activities and then to resume development when placed in aerobic sea water. However, this unique characteristic of Artemia franciscana embryos is lost during a very short period, at the embryonic&shy;larval transition period of development, coincident with the appearance of prenauplius larvae. Thus, while encysted embryos show complete inhibition of proteolysis over at least 4 years under anoxia, control of this activity, together with resistance to anoxia, is lost in newly hatched nauplius larvae after only a few days in anaerobic sea water. In contrast to encysted embryos, young larvae in anaerobic sea water produce large amounts of lactic acid, which reaches a concentration of nearly 50 mmol l-1 within 12 h of incubation. The accumulated lactic acid is believed to reduce the intracellular pH (pHi) to considerably less than 6.3, the value found in encysted embryos after 5 months in anaerobic sea water. We find that larvae, in contrast to embryos, lose cytoplasmic proteins at the rate of 4&shy;5 ng h-1 larva-1 upon transfer to anaerobic sea water, while yolk proteins are not degraded in either embryos or larvae under anoxic conditions. The decline in cytoplasmic protein levels in anaerobic larvae may be due to activation of an endogenous cysteine protease (CP) as the pHi becomes acidic. Contributing to the apparent uncontrolled CP activity is a decrease in the level of cysteine protease inhibitor (CPI) activity during the embryonic&shy;larval transition period, resulting in an increase in the CP/CPI ratio, from approximately 0.5 in embryos to greater than 1.0 in newly hatched larvae. Finally, data are presented to suggest that loss of the 26 kDa stress protein from embryos during the embryonic&shy;larval transition may also contribute to the loss in resistance of young nauplius larvae of A. franciscana to anaerobic conditions.

Multiparameter models for the prediction of sepsis outcome

This study reports the predictive value, in septic patients, of septic shock at presentation (SS factor) alone and in combination with multiple markers, using survival of the sepsis episode as the outcome measure. The SS factor correctly predicted the outcome in 53/68 (78%) of patients in this study. The Acute Physiology and Chronic Health Evaluation II Score (APACHE II or APII) and interleukin-6 (IL-6) and IL-6 soluble receptor (IL-6sR) concentrations were evaluated in combination with the SS factor in the same 68 patient population which was randomly divided into design (# = 50) and test groups (# = 18). Two iterations of an algorithm were evaluated using randomized patient groups corresponding to those producing the best (Group A) and worst (Group B) performance using a neural network. The four-input algorithm (APII, IL-6, IL-6sR, SS factor) correctly classified 16/18 (89%, Group A) and 14/18 (78%, Group B) of patients in the test subset. The corresponding four-input neural network model (10 iterations) correctly classified 61 to 89% of the 18 patients in the 10 test subsets.

Prognostic potential of cytokines, nitrates, and APACHE II score in sepsis

The prognostic potentials of physiological ([Acute Physiologic and Chronic Health Evaluation] APACHE II score) and biochemical (Interleukin 6 [IL-6], Interleukin 6 soluble receptor [IL-6sR], and Interleukin 2 receptor [IL-2R], nitrates) measures were evaluated in sepsis. The APACHE II scores were calculated, and concentrations of the biochemical markers were measured, based upon information and samples obtained from 68 septic patients at time of diagnosis. Outcome (survival/non-survival) was determined at the end of the hospital stay associated with the septic episode. Statistically significant differences between survivors (S) and non-survivors (non-S) were found for APACHE II (p < 0.0001), IL-6 (p < 0.005), IL-6sR (p < 0.05), IL-2R (p < 0.02). No significant differences were found for nitrates. None of the markers could serve individually as an effective prognostic indicator. However, those markers demonstrating a significant difference between survivors and non-survivors may be able to contribute to a multi-parameter prognostic model.

Expression of intercellular junctions during preimplantation development of the human embryo

A total of 74 human embryos were stained with gap junction protein specific anti-peptide antibodies an antibodies to the desmosomal protein desmoplakin to reveal the expression pattern of intercellular junctions during preimplantation development. Prior to implantation, the human embryo expresses predominantly connexin (Cx43)-containing gap junctions. Gap junctions were first detected in apposing cell membranes at the 4-cell stage and became increasingly organized as development proceeded. In normal blastocysts, trophectoderm (TE) cells were linked by dense arrays of gap junctions while inner cell mass (ICM) cells were linked by small, punctate gap junctions. Gap junctions containing Cx32 or Cx26 were observed occasionally in the TE of late blastocysts. Desmosomes appeared between outer cells prior to cavitation and were retained in the TE, but not in the ICM. Levels of gap junction protein expression were variable in morphologically normal embryos at the same stage, suggesting that a normal appearance may not be a reliable indicator of future viability. Morphologically normal embryos often possessed multinucleate, apoptotic and decompacting cells. They could show either extensive, disorganized over-expression or reduced expression of gap junction protein. The results fit the view that only embryos destined to survive display an organized pattern of intercellular junctions.

Reovirus infection in rat lungs as a model to study the pathogenesis of viral pneumonia

We undertook the present study to elucidate the pathogenesis of the pathologic response to reovirus infection in the lungs and further understand the interactions of reoviruses with pulmonary cells. We found that reoviruses were capable of causing acute pneumonia in 25- to 28-day-old Sprague-Dawley rats following intratracheal inoculation with the reoviruses type 1 Lang (T1L) and type 3 Dearing (T3D). The onset of the pneumonia was rapid, marked by type I alveolar epithelial cell degeneration, type II alveolar epithelial cell hyperplasia, and the infiltration of leukocytes into the alveolar spaces. More neutrophils were recruited into the lungs during T3D infection than during T1L infection, and the serotype difference in the neutrophil response was mapped to the S1 gene of reovirus. Viral replication in the lungs was required for the development of pneumonia due to T1L and T3D infections, and replication occurred in type I alveolar epithelial cells. T1L grew to higher titers in the lungs than did either T3D or type 3 clone 9, and the S1 gene was found to play a role in determining the level of viral replication. We propose that experimental reovirus infection in the lungs can serve as a model for the pathogenesis of viral pneumonia in which pulmonary inflammation results following direct infection of lung epithelial cells.

Specific motifs in the external loops of connexin proteins can determine gap junction formation between chick heart myocytes

1. Gap junction formation was compared in the absence and presence of small peptides containing extracellular loop sequences of gap junction (connexin) proteins by measuring the time taken for pairs of spontaneously beating embryonic chick heart myoballs to synchronize beat rates. Test peptides were derived from connexin 32. Non-homologous peptides were used as controls. Control pairs took 42 +/- 0.5 min (mean +/- S.E.M.; n = 1088) to synchronize. 2. Connexins 32 and 43, but not 26, were detected in gap junction plaques. The density and distribution of connexin immunolabelling varied between myoballs. 3. Peptides containing conserved motifs from extracellular loops 1 and 2 delayed gap junction formation. The steep portion of the dose-response relation lay between 30 and 300 microM peptide. 4. In loop 1, the conserved motifs QPG and SHVR were identified as being involved in junction formation. In loop 2, the conserved SRPTEK motif was important. The ability of peptides containing the SRPTEK motif to interfere with the formation of gap junctions was enhanced by amino acids from the putative membrane-spanning region. 5. Peptides from loop 1 and loop 2 were equivalently effective; there was no synergism between them. 6. The inclusion of conserved cysteines in test peptides did not make them more effective in the competition assay.

Prognostic role of antioxidant enzymes in sepsis: preliminary assessment

The prognostic potential of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) was evaluated in sepsis. Enzyme concentrations were determined in samples obtained from septic patients at time of diagnosis. Statistically significant increases in activities of total plasma SOD (P < 0.003, n = 32), erythrocyte (RBC) SOD (P < 0.007, n = 16), plasma CAT (P < 0.0001, n = 32), and RBC CAT (P < 0.005, n = 16) were found in septic patients when compared with healthy adult controls (n = 7). Further, within the group of septic patients, statistically significant differences were found for total plasma SOD (P < 0.05) and plasma CAT (P < 0.009) (but not for RBC determinations) when survivors (n = 15) were compared with nonsurvivors (n = 17). No significant differences were found for either plasma or RBC enzyme concentrations when patients who developed adult respiratory distress syndrome were compared with those who did not. The most striking finding was that plasma total SOD values of > 10 kU/L were found in 7 of 21 (30%) patients who did not survive their sepsis and that these values did not overlap with any surviving patients or controls. However, while high total plasma SOD activity appears to have some potential as a prognostic indicator, lower values (0.0-8.8 kU/L) do not. For plasma CAT, despite finding statistically significant differences between survivors and nonsurvivors, the substantial overlap in the values obtained for the two groups limits the practical prognostic potential of this enzyme.

Prognostic role of antioxidant enzymes in sepsis: preliminary assessment

The prognostic potential of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) was evaluated in sepsis. Enzyme concentrations were determined in samples obtained from septic patients at time of diagnosis. Statistically significant increases in activities of total plasma SOD (P &lt; 0.003, n = 32), erythrocyte (RBC) SOD (P &lt; 0.007, n = 16), plasma CAT (P &lt; 0.0001, n = 32), and RBC CAT (P &lt; 0.005, n = 16) were found in septic patients when compared with healthy adult controls (n = 7). Further, within the group of septic patients, statistically significant differences were found for total plasma SOD (P &lt; 0.05) and plasma CAT (P &lt; 0.009) (but not for RBC determinations) when survivors (n = 15) were compared with nonsurvivors (n = 17). No significant differences were found for either plasma or RBC enzyme concentrations when patients who developed adult respiratory distress syndrome were compared with those who did not. The most striking finding was that plasma total SOD values of &gt; 10 kU/L were found in 7 of 21 (30%) patients who did not survive their sepsis and that these values did not overlap with any surviving patients or controls. However, while high total plasma SOD activity appears to have some potential as a prognostic indicator, lower values (0.0-8.8 kU/L) do not. For plasma CAT, despite finding statistically significant differences between survivors and nonsurvivors, the substantial overlap in the values obtained for the two groups limits the practical prognostic potential of this enzyme.

Failure of intravenous metoprolol to limit acute myocardial infarct size in a nonreperfused porcine model

The usefulness of intravenous beta-adrenergic receptor blockade in limiting infarct size when neither reperfusion nor collateral flow occurs is unknown. The effect of intravenous metoprolol on limiting myocardial infarct size was therefore examined in a nonreperfused porcine model. Closed-chest techniques were used to occlude the left anterior descending coronary artery, after which animals were randomized at 20 minutes to receive intravenous metoprolol, 0.75 mg/kg, or placebo. Infarct size examined at 5 hours with Evans blue and triphenyltetrazolium staining techniques was expressed as a percentage of total ventricular myocardium at ischemic risk. This percentage was not significantly different between the groups (84% +/- 5% with metoprolol vs 90% +/- 4% with placebo; p = 0.4). Myocardial infarct size was not significantly decreased at 5 hours by early administration of intravenous metoprolol when the infarct artery remained occluded and collateral flow was minimal.

Functional analysis of amino acid sequences in connexin43 involved in intercellular communication through gap junctions

Gap junctions allow direct communication between cells without recourse to the extracellular space and have been widely implicated as important mediators of cell-cell signalling. They are constructed from the connexin proteins, which form a large family, and individual connexins show complex spatial and temporal variations in their expression patterns. Understanding how this variation contributes to the control of intercellular signalling, both in the adult and during embryonic development, is an important problem that would be aided by reagents that interfere with gap junctional communication through specific connexins. We have begun to address this issue by raising antibodies to peptides derived from connexin43 and connexin32. Connexin43 peptides were located in the amino terminus, cytoplasmic loop and carboxytail. Connexin32 peptides came from the cytoplasmic loop and the first extracellular loop. Immunoblotting and immunostaining properties of purified IgGs were characterized on mouse heart, liver and the 8- to 16-cell mouse embryo. Effects on transfer through gap junctions were assessed in the fully compacted 8-cell mouse embryo by co-injection with Lucifer Yellow or Cascade Blue. Embryos were maintained in culture to assess the developmental consequences of injection. Peptide competition was used to confirm the specificity of immunostaining and inhibition of dye transfer. All connexin specific antibodies recognized their parent connexin on immunoblots and showed no 43/32 cross-reactivity. The connexin32 extracellular loop antibody recognized both connexin 32 and 43 on immunoblots, as predicted by the amino acid sequence homology in this region, but did not immunostain intact gap junctions. Connexin specific antibodies that immuno-stained showed the predicted connexin specificity. Antibodies to either connexin43 amino acids (AA) 1–16 (amino terminus) or AA 101–112 (cytoplasmic loop) neither immunostained nor prevented functional communication through 8-cell embryo gap junctions. Antibodies to AA 123–136 and AA 131–142 in the cytoplasmic loop immunostained heart and 8-cell embryo gap junctions and blocked transfer through them with high efficiency. Fab' fragments were equally effective. Peptide competition showed that both antibodies contained epitopes within AA 131–136 of connexin43. Antibodies against AA 313–324 in the carboxytail immunostained heart and the 8-cell embryo and, as IgGs, prevented dye transfer. Fab' fragments were ineffective. All connexin43 antibodies that blocked gap junctional communication between cells of the 8-cell mouse embryo induced non-communicating cells subsequently to withdraw from compaction.(ABSTRACT TRUNCATED AT 400 WORDS)

Mite allergens in relation to home conditions and sensitization of asthmatic children from three climatic regions

We investigated the levels of mite (Der p I and Der f I) allergen in dust from bedrooms, living rooms, kitchens, and bathrooms from 130 homes of asthmatic children in three climatic zones of Sweden. Bedroom dust samples included the child's mattress, carpets, floors, and other plain surfaces. Living-room dust samples were taken from sofas and other furniture, carpets, floors, and other plain surfaces. The allergen levels were related to home characteristics, including absolute indoor humidity (AIH), relative humidity (RH), and air changes per hour (ach). Mite allergen was detected in 62% of the homes. Levels of Der p I varied between < 16 ng and 50 micrograms/g dust, and Der f I between < 16 ng and 73 micrograms/g dust. Because we have designed a composite type of dust collection in our study, the allergen levels found tend to average down the results. Mite allergen levels were higher in homes with dampness problems, in homes with a smoker, and in homes without a basement. Homes with high absolute humidity (> or = 7 g/kg) or relative humidity (> or = 45%) and poor ventilation (< 0.5 ach) contained higher levels of mite allergens than homes with lower humidity and better ventilation. However, the number of ach measurements in homes was not high, and few homes had > 0.5 ach. Sensitization to house-dust mites was more common in southern than in northern and central Sweden. High levels of house-dust mite allergen in a temperate climate where mites are not ubiquitous are thus associated with dampness problems in homes and with tobacco smoking. Our data confirm and extend previous findings that high AIH and RH and poor ventilation increase the risk of mite infestation in homes. It seems to be important and necessary to control indoor humidity and ventilation levels, to avoid high mite allergen exposure in a temperate climate, because 34% of mite-sensitized asthmatic children were exposed to levels of mite allergen < 2 micrograms/g dust in their homes. The study also shows that mite allergen levels below the suggested threshold level (2 micrograms/g dust) are associated with mite sensitivity in children with perennial symptoms of asthma.

A pathway for entry of reoviruses into the host through M cells of the respiratory tract

Many microorganisms gain access to the systemic circulation after entering the respiratory tract. The precise pathways used to cross the mucosal barriers of the lungs have not been clearly described. We have used the mammalian reoviruses in order to determine the pathway that a systemic virus uses to penetrate the mucosal barrier and enter the systemic circulation after entering the airways of the lungs. Reoviruses enter through pulmonary M cells, which overlie bronchus-associated lymphoid tissue, and subsequently spread to regional lymph nodes. Thus, the pathway through M cells represents a strategy by which viruses and probably other microorganisms can penetrate the mucosal surface of the respiratory tract and thereby enter the systemic circulation.

Cat (Fel d I), dog (Can f I), and cockroach allergens in homes of asthmatic children from three climatic zones in Sweden

We have investigated the levels of cat (Fel d I), dog (Can f I), and cockroach (Per a I) allergens in dust from bedrooms, living rooms, kitchens, and bathrooms from 123 homes of asthmatic children in three zones of Sweden with varying climates. Absolute indoor humidity (AIH), relative humidity (RH), rate of ventilation in air changes per hour (ach), and number of airborne particles were also measured. Fel d I, Can f I, and Per a I allergen contents were determined by mab ELISA, and the levels were related to various environmental factors. The major cat allergen, Fel d I, was detected in all homes, and the concentrations varied between 16 ng and 28,000 ng/g fine dust. The dog allergen, Can f I, was detected in 85% of the homes, and the levels varied from 60 ng to 866,000 ng/g dust. Cockroach allergen was detected in only one home (40 ng/g). Fel d I and Can f I allergens were equally distributed geographically. Dust from living rooms contained significantly higher (P < 0.05) concentrations of both Fel d I and Can f I allergens than dust from bedrooms, kitchens, and bathrooms. The levels tended to be higher in homes with poor ventilation (< 0.5 ach) and in homes with wall-to-wall carpets. Significantly higher (P < 0.01) numbers of airborne particles were found in homes with high humidity (i.e., AIH > or = 7 g/kg or RH > or = 45%).(ABSTRACT TRUNCATED AT 250 WORDS)

Low intracellular pH is involved in the early embryonic death of DDK mouse eggs fertilized by alien sperm

Intracellular pH was measured in normal 8-cell stage mouse embryos and in embryos from a cross between DDK females and C3H males. DDK/C3H embryos display the DDK syndrome and spontaneously begin to decompact toward the late 16-cell stage. Ultimately, 90% fail to form blastocysts. Normal embryos have a resting intracellular pH close to neutrality. In DDK/C3H embryos a substantial proportion (46%) has an intracellular pH below 6.7. An equivalent proportion of DDK/C3H embryos was found previously to show slow communication through gap junctions at the 8-cell stage. This is probably a consequence of low intracellular pH. In normal embryos the weak acid, butyric acid, decreased intracellular pH and slowed the transfer of Lucifer Yellow through gap junctions. Normal embryos treated with butyrate for between 1 and 6 hr beginning at the 8-cell stage and cultured for 24 hr, reproduced the DDK/C3H phenotype. After 48 hr some butyrate treated embryos recovered, while others remained as decompacted morulae. Treatment of control and DDK/C3H 8-cell stage embryos with dibutyryl cyclic AMP or forskolin, which will increase intracellular cyclic AMP, speeded gap junctional communication. Forskolin treatment prevented expression of the DDK syndrome in DDK/C3H embryos, although the rescue was transient and the syndrome returned when forskolin was removed. The finding that the DDK syndrome is manifested as low intracellular pH may provide clues to the molecular basis of the defect.

Victim resistance and judgments of victim "consensuality" in rape

38 participants read about a man who entered a woman's apartment at night, told her that "all he wanted was sex," engaged in the act of sex regardless of what she said or did, and then left. Participants then made a preliminary rating of their agreement or disagreement with the statement. "The woman consented to have sex." To learn how victim's resistance might add or subtract from judgments of victim's "consensuality," participants then read four additional scenarios about how the woman might have responded to the man. Analysis indicated that the absence of any verbal or physical resistance (e.g., "OK--please don't hurt me," or "Please wear a condom--I'm afraid of getting AIDS") increased judgments of victim's consensuality.

Extracellular calcium does not contribute to cryopreservation-induced cytotoxicity

The possible role of extracellular calcium ([Ca+2]e) in cryopreservation-induced cytotoxicity was tested using Madin-Darby canine kidney (MDCK) cells and a fluorescent multiple endpoint assay. MDCK cells maintained in 2 mM [Ca+2]e and treated with the calcium ionophore, ionomycin, increased their intracellular calcium ([Ca+2]i) as revealed by the calcium indicator dye, Fluo3 and the bottom-reading spectrofluorometer, CytoFluor 2300. The addition of 10 mM [ethylene bis (oxyethylenenitrilo)]-tetraacetic acid (EGTA) to the extracellular medium before treatment with ionomycin blocked this ionomycin-dependent increase in [Ca+2]i. A number of site and activity-specific fluorescent probes were surveyed to determine which indicator dye might best reveal the ionomycin-induced cytotoxic events during this increase in [Ca+2]i. Although most dyes changed their emission profiles in response to calcium, neutral red was found to best reflect the loss of [Ca+2]i homeostasis. The NR50 for a 15-min exposure to ionomycin in the presence of 2 mM [Ca+2]e was approximately 2 microM ionomycin, but ionomycin had little apparent effect on neutral red retention when 10 mM EGTA was added to the extracellular medium. Thus it was clear that an increase in [Ca+2]i could be cytotoxic to MDCK cells and that neutral red could monitor this cytotoxic episode. To test if [Ca+2]e was similarly cytotoxic during cryopreservation, MDCK cells were subjected to cryopreservation in the presence of dimethylsulfoxide (DMSO). In contrast to previous studies, plasma membrane integrity, not lysosomal function, seemed to best correlate with cell survival subsequent to cryopreservation. In addition, decreasing [Ca+2]e had no discernable effect on the retention of plasma membrane indicator dyes, neutral red, or cell survival. It is concluded that a) plasma membrane indicator dyes, not neutral red, might be better indicators of cytotoxicity occurring during cryopreservation; b) DMSO might be toxic to lysosomes during cryopreservation of cultured cells; and c) although [Ca+2]e can contribute to cytotoxicity, the presence of [Ca+2]e might not influence cryopreservation-induced cytotoxicity.

Gap junctions in development--a perspective

The status of the gap junction as a pathway for cellular interactions during development is reviewed. Current evidence suggests that gap junctions play an important part in ensuring normal development, although the precise role of gap junctional communication remains to be defined. Communication through gap junctions acts alongside cellular interactions achieved by the release of growth factors during embryogenesis. Differences between groups of developing cells may be reflected in, and possibly controlled by, alterations in the selectivity of the gap junctions. It seems likely that gap junctional communication is involved in the control of embryonic patterning rather than phenotypic differentiation.

Effects of captopril on contractility after myocardial infarction: experimental observations

After large myocardial infarction, compromised left ventricular (LV) function and changes in the peripheral circulation result in the syndrome of chronic congestive heart failure. Although treatment with angiotensin-converting enzyme inhibitors improve cardiovascular function, it is difficult to determine whether this benefit is due to changes in organ versus muscle function. The rat model of heart failure, created by ligating the left coronary artery, results in pathophysiology that is similar to that seen in patients, i.e., increased LV end-diastolic pressure and volume, hypertrophy of the noninfarcted myocardium, prolongation of the time constant of LV relaxation, decreased venous compliance, and increased total blood volume. In noninfarcted papillary muscles, isolated from rats with heart failure, maximal developed tension and peak rate of tension rise (+dT/dt) are decreased, time to peak tension is prolonged, and myocardial stiffness is increased. Morphologic changes include an increase in papillary muscle myocyte cross-sectional area and an increase in myocardial hydroxyproline content. Captopril (2 g/liter drinking water) alters LV loading by decreasing arterial pressure, increasing venous compliance, and decreasing blood volume. This results in a decrease in LV end-diastolic pressure and volume. In the noninfarcted myocardium, time to peak tension is shortened, whereas developed tension, +dT/dt, and muscle stiffness remain abnormal. Captopril decreases myocyte cross-sectional area, but collagen content remains elevated. Thus, in the rat infarct model of heart failure, treatment with captopril alters LV remodeling and hypertrophy but produces only modest improvement in muscle function.(ABSTRACT TRUNCATED AT 250 WORDS)

New rapid method for the study of Pneumocystis carinii interaction with alveolar macrophages

Understanding the pathophysiology of Pneumocystis carinii infection has been limited by the availability of methods for precisely measuring the interaction of P. carinii with host cells. Here we describe a new method which allows for the rapid assessment of P. carinii binding to, and internalization by, adherent alveolar macrophages. The method is based on the detection of fluorescein-labelled P. carinii by an automated fluorescence measurement system.

Uptake of Pneumocystis carinii mediated by the macrophage mannose receptor

Human exposure to Pneumocystis carinii is common but, in the absence of acquired or genetic dysfunction of either cellular or humoral immunity, exposure rarely leads to illness. Although alveolar macrophages can degrade P. carinii, macrophage receptors involved in P. carinii recognition have not been clearly defined. Characterization of a predominant surface glycoprotein of the high mannose type led us to investigate the role of the macrophage mannose receptor in this process. We report here that binding and uptake of cultured rat P. carinii by human and rat alveolar macrophages is reduced by 90% in the presence of competitive inhibitors of mannose receptor activity and by adherence of alveolar macrophages to mannan-coated surfaces. Further, only those COS cells transfected with the human macrophage mannose receptor complementary DNA that express surface mannose receptors bind and ingest P. carinii. These studies establish that the macrophage mannose receptor is sufficient for uptake of P. carinii and emphasize the role of the alveolar macrophage in first-line host defence against P. carinii.

Characterization of the airway smooth muscle muscarinic receptor in vivo

We examined the bronchodilator activity of eight subtype-selective and non-selective muscarinic antagonists in anesthetized, ventilated guinea pigs bronchoconstricted by carbachol aerosols. Relative bronchodilator potencies were consistent with M3 receptor antagonism and correlated with inhibition of bladder smooth muscle contraction in vivo. We conclude that the airway smooth muscle muscarinic receptor can be functionally characterized in vivo as M3 and that it is of the same subtype as the muscarinic receptor in bladder smooth muscle.

In vitro/in vivo evaluation of hydrochlorothiazide in experimental hydrochlorothiazide/triamterene combination tablets in beagle dogs

The purpose of this study was to compare experimental formulations containing hydrochlorothiazide (CAS 58-93-5)/triamterene (HCT/TRI) in vitro and in vivo to a commercial tablet formulation (standard). The beagle dog was verified as a good model and was used for the in vivo studies. The commercial tablet and the experimental fast release formulation (FR) resulted in 100% release of HCT within 30 min in dissolution tests, whereas, the slow release formulation (SR) released only 54% HCT after 4 h. Relative bioavailability of the FR and SR formulations were 82 and 41%, respectively, compared to the commercial tablet. The experimental results indicate that HCT absorption occurs throughout the small intestine.

Gap junctional communication during neuromuscular junction formation

We have tested whether gap junctions form between nerve and muscle during their initial contact, before establishing the chemical synapse. Embryonic Xenopus stage 18-20 myotomes and neural tubes were permeabilized with DMSO to load appropriate reagents, dissociated, and cocultured. When myotomes, loaded with Lucifer yellow, were cocultured with unlabeled neural tube cells, 23% of the neurons contained dye after 24 hr. Affinity-purified gap junction antibodies loaded into myocytes or neurons reduced neuronal labeling significantly to 5%. [3H]uridine nucleotide transfer was observed in both directions between myocytes and neurons. Again gap junction antibodies substantially reduced recipient label. In all cases preimmune IgGs did not reduce transfer. When acetylcholine receptor clustering was examined in cultures containing gap junction antibodies, no difference in the number of neuronally induced AChR clusters was observed. This suggests that the cluster-inducing signal between nerve and muscle does not pass through gap junctions.