Acute effects of inhaled urban particles and ozone: lung morphology, macrophage activity, and plasma endothelin-1

We studied acute responses of rat lungs to inhalation of urban particulate matter and ozone. Exposure to particles (40 mg/m3 for 4 hours; mass median aerodynamic diameter, 4 to 5 microm; Ottawa urban dust, EHC-93), followed by 20 hours in clean air, did not result in acute lung injury. Nevertheless, inhalation of particles resulted in decreased production of nitric oxide (nitrite) and elevated secretion of macrophage inflammatory protein-2 from lung lavage cells. Inhalation of ozone (0.8 parts per million for 4 hours) resulted in increased neutrophils and protein in lung lavage fluid. Ozone alone also decreased phagocytosis and nitric oxide production and stimulated endothelin-1 secretion by lung lavage cells but did not modify secretion of macrophage inflammatory protein-2. Co-exposure to particles potentiated the ozone-induced septal cellularity in the central acinus but without measurable exacerbation of the ozone-related alveolar neutrophilia and permeability to protein detected by lung lavage. The enhanced septal thickening was associated with elevated production of both macrophage inflammatory protein-2 and endothelin-1 by lung lavage cells. Interestingly, inhalation of urban particulate matter increased the plasma levels of endothelin-1, but this response was not influenced by the synergistic effects of ozone and particles on centriacinar septal tissue changes. This suggests an impact of the distally distributed particulate dose on capillary endothelial production or filtration of the vasoconstrictor. Overall, equivalent patterns of effects were observed after a single exposure or three consecutive daily exposures to the pollutants. The experimental data are consistent with epidemiological evidence for acute pulmonary effects of ozone and respirable particulate matter and suggest a possible mechanism whereby cardiovascular effects may be induced by particle exposure. In a broad sense, acute biological effects of respirable particulate matter from ambient air appear related to paracrine/endocrine disruption mechanisms.

Myasthenia gravis presenting with dysphagia and postoperative ventilatory failure

We report a case of myasthenia gravis presenting to the department of otolaryngology with acute dysphagia on two separate occasions over a one-year period. Diagnosis of myasthenia gravis was made when the patient developed ventilatory failure after his second general anaesthetic for rigid oesophagoscopy. Our patient required emergency transfer to the intensive therapy unit for ventilation. He improved after treatment with corticosteroids, anticholinesterase and immunosuppressive medications. Our case was unusual in that cricopharyngeal spasm causing dysphagia and significant aspiration was demonstrated by a barium swallow and this was completely resolved after treatment of the myasthenia gravis.

NTF2 mediates nuclear import of Ran

Importin beta family transport receptors shuttle between the nucleus and the cytoplasm and mediate transport of macromolecules through nuclear pore complexes (NPCs). The interactions between these receptors and their cargoes are regulated by binding RanGTP; all receptors probably exit the nucleus complexed with RanGTP, and so should deplete RanGTP continuously from the nucleus. We describe here the development of an in vitro system to study how nuclear Ran is replenished. Nuclear import of Ran does not rely on simple diffusion as Ran's small size would permit, but instead is stimulated by soluble transport factors. This facilitated import is specific for cytoplasmic RanGDP and employs nuclear transport factor 2 (NTF2) as the actual carrier. NTF2 binds RanGDP initially to NPCs and probably also mediates translocation of the NTF2-RanGDP complex to the nuclear side of the NPCs. A direct NTF2-RanGDP interaction is crucial for this process, since point mutations that disturb the RanGDP-NTF2 interaction also interfere with Ran import. The subsequent nuclear accumulation of Ran also requires GTP, but not GTP hydrolysis. The release of Ran from NTF2 into the nucleus, and thus the directionality of Ran import, probably involves nucleotide exchange to generate RanGTP, for which NTF2 has no detectable affinity, followed by binding of the RanGTP to an importin beta family transport receptor.

Patient-physician communication assessment instruments: 1986 to 1996 in review

This paper provides a comprehensive review and comparison of instruments used to assess patient-doctor interaction over the past decade. Instruments were identified from papers indexed by MEDLINE from 1986 to 1996 using the medical subject headings 'physician-patient relations', 'physician-patient communication', and 'education, medical', as well as requests for instruments currently in use by colleagues. Each instrument was reviewed under the following categories: name of the instrument; description; number of items; reliability; validity; current use and special notes. Overall, 44 instruments were obtained and reviewed. Of these, 21 were used in only one published study each in the last decade and 15 have never been validated. While most instruments have been shown to be reliable (usually inter-rater reliability), very few instruments have been directly compared with another instrument designed to assess patient-doctor interactions. We suggest that further validation of existing instruments and incorporation of assessment of non-verbal communication between the patient and the doctor are needed.

Patient-physician communication assessment instruments: 1986 to 1996 in review

This paper provides a comprehensive review and comparison of instruments used to assess patient-doctor interaction over the past decade. Instruments were identified from papers indexed by MEDLINE from 1986 to 1996 using the medical subject headings 'physician-patient relations', 'physician-patient communication', and 'education, medical', as well as requests for instruments currently in use by colleagues. Each instrument was reviewed under the following categories: name of the instrument; description; number of items; reliability; validity; current use and special notes. Overall, 44 instruments were obtained and reviewed. Of these, 21 were used in only one published study each in the last decade and 15 have never been validated. While most instruments have been shown to be reliable (usually inter-rater reliability), very few instruments have been directly compared with another instrument designed to assess patient-doctor interactions. We suggest that further validation of existing instruments and incorporation of assessment of non-verbal communication between the patient and the doctor are needed.

Alcohol versus natural drying for newborn cord care

OBJECTIVE

To compare alcohol cleaning and natural drying of newborn umbilical cords.

DESIGN

Prospective, randomized controlled trial.

SETTING

Tertiary-level university teaching hospital and level II community hospital.

PARTICIPANTS

Of 1,876 singleton full-term newborns enrolled, 1,811 completed the study.

INTERVENTIONS

Newborns, from birth until separation of the cord, were randomized to either (a) umbilical cleansing with 70% isopropyl alcohol at each diaper change or (b) natural drying of the umbilical site without special treatment.

MAIN OUTCOME MEASURES

Umbilical infection, cord separation time, maternal comfort, and cost.

RESULTS

No newborn in either group developed a cord infection. Primary care providers obtained cultures for cord concerns in 32 newborns (1.8%), with colonization for normal flora, Staphylococcus aureus, and Group B streptococcus proportionately equal in alcohol and air dry groups. Cord separation time was statistically significantly different (alcohol group, 9.8 days; natural drying group, 8.16 days; t = 8.9, p = < .001). Mothers described similar comfort with cord care and relief with cord separation. Costs of alcohol drying while in the hospital were greater than those of natural drying.

CONCLUSIONS

(a) Evidence does not support continued use of alcohol for newborn cord care; (b) health care providers should explain the normal process of cord separation, including appearance and possible odor; and (c) health care providers should continue to develop evidence to support or eliminate historic practices.

Changing face of family practice

OBJECTIVE

To identify trends in family practice in London, Ont, between 1974 and 1994.

DESIGN

Interview survey of all London family physicians in 1974. Questionnaire surveys in 1984 and 1994.

SETTING

City of London, Ont.

PARTICIPANTS

One hundred twenty-eight family physicians and general practitioners practising in London in 1974, 180 in 1984, and 237 in 1994.

RESULTS

The percentage of female practitioners, practitioners with no in-hospital patients, and practitioners making no home visits in an average week increased significantly. The percentage of solo practitioners and family physicians practising obstetrics decreased significantly. Changes were found in the numbers of patients seen, in weekend coverage, in evening, and Wednesday afternoon office hours, and in level of satisfaction with practice.

CONCLUSION

Fewer physicians cared for in-hospital patients, made home visits, practised solo, and delivered babies in 1994 than in 1974. Substantially more women were practising family medicine in 1994 than in 1974. The trend away from in-hospital care, with no corresponding increase in home care, raises questions about how urban family physicians can maintain certain clinical skills.

Decisions and justifications by community mental health providers about hypothetical ethical dilemmas

OBJECTIVE

Community-based treatment of persons with serious mental illness requires providers to become involved in clients' personal lives to a greater degree than does hospital-based treatment. The study examined attendant ethical dilemmas, especially for staff who lack professional training or work in rural communities.

METHODS

A total of 95 staff members from five community mental health centers read 14 vignettes describing ambiguous ethical dilemmas involving professional role boundaries or client confidentiality. Twenty-seven staff members were from rural agencies, and 68 from urban-suburban agencies; 60 were direct care staff, and 35 were supervisory. Participants were asked to make and justify a more conservative or a less conservative decision in response to each dilemma.

RESULTS

Years of experience as a mental health provider and previous ethics training correlated positively with staff having experienced more situations similar to those in the vignettes; however, these variables were not related to the decision made or the type of ethical justification for it. When the analysis controlled for experience and previous ethics training, staff made fewer conservative decisions in boundary dilemmas than in confidentiality dilemmas. Compared with nonrural providers, rural providers had experienced more boundary dilemmas and made fewer conservative decisions in response to them.

CONCLUSIONS

Boundary problems occur frequently in community-based services, especially in rural settings, and may or may not be handled conservatively. With the expansion of case management and other in vivo services, better understanding of ethical risks and informal practices will help improve services and provide appropriate training and supervision of staff.

Medical and social factors associated with the admission and discharge of acutely ill children

AIM

To examine medical and sociodemographic factors involved in acute paediatric admission. To compare outcome of admission with factors present at time of admission.

METHODS

Prospective questionnaire based study of 887 consecutive emergency general paediatric admissions to five Yorkshire hospitals during two separate three week periods in summer and winter.

MAIN OUTCOME MEASURES

Discharge diagnosis, length of stay.

RESULTS

Most admissions (53%) occurred "out of hours" with a peak during the evening. Two thirds (64%) of patients were under 3 years of age and clinical problems varied with age. Self referral via an accident and emergency department occurred in one third and was more likely after a fit in older children and in more socioeconomically deprived children. The most frequent presenting problems were breathing difficulty (24%), fit (16%), and feverish illness (15%). One quarter (24%) were discharged within 24 hours and 61% spent, at most, one night in hospital. Length of stay was shorter for night admissions and longer for children with a discharge diagnosis of asthma. Although most children had mild, self limiting illnesses, serious illness was subsequently found in 13% and could not be predicted from the presenting problems.

CONCLUSIONS

Current demand on emergency paediatric admission is mainly from young children with mild self limiting illnesses who spend one night or less in hospital. Changes in delivery of care to acutely ill children must take account of the pattern and nature of presenting problems and be rigorously audited to ensure that improvements in the health of children continue.

Parental and professional perception of need for emergency admission to hospital: prospective questionnaire based study

AIM

To compare views of parents, consultants, and general practitioners on severity of acute illness and need for admission, and to explore views on alternative services.

METHOD

Prospective questionnaire based study of 887 consecutive emergency paediatric admissions over two separate three week periods in summer and winter of five Yorkshire hospitals, combined with a further questionnaire on a subsample.

OUTCOME MEASURES

Parental scores of need for admission and parent and consultant illness severity scores out of 10. Consultant judgment of need for admission. Alternatives to admission considered by consultants and, for a subsample, by parents and family GP.

RESULTS

Ninety nine per cent of parents thought admission was needed. Parents scored need for admission more highly than severity of illness with no association observed between severity and presenting problem or diagnosis. High parental need score was associated with a fit, past illness, and length of stay. Consultant illness severity scores were skewed to the lower range. Consultants considered admission necessary in 71%, especially for children aged over 1 year, presentation with breathing difficulty or fit, and after a longer stay. More admissions in the evening were considered unnecessary as were admissions after longer preadmission illness, gastroenteritis, or upper respiratory tract infection. Of a subsample of parents, 81% preferred admission during the acute stage of illness even if home nursing had been available. Similar responses were obtained from GPs. Alternative services could have avoided admission for 19% of children, saving 15.6% of bed days used.

CONCLUSIONS

Medical professionals and parents differ in their views about admission for acute illnesses. More information is needed on children not admitted. Alternative services should take account of patterns of illness and should be acceptable to parents and professionals; cost savings may be marginal.

Open versus closed diagnostic peritoneal lavage: a comparison on safety, rapidity, efficacy

There is considerable debate between the proponents of open and closed diagnostic peritoneal lavage (DPL). A prospective study was undertaken on 130 patients submitted to DPL. We performed 55 (42.3%) closed and 75 (57.7%) open lavages with sensitivity and specificity of 100 and 96.6% for the former and 92.2 and 100% for the latter. The mean time for insertion of the catheter and initiation of fluid infusion was significantly less in the closed DPL group, and so were the number of cases with prolonged procedures. No intra-abdominal or wound complications were detected with either method, but there were 10 DPL failures due to inability to conclude the procedure successfully and derive a definite result. Eight of these (10.6%) belonged to the open group and two (3.6%) to the closed (P < 0.05). Our findings suggest closed DPL is as equally sensitive and specific as closed DPL, but is more expeditious and offers inconclusive results less often. Both procedures are useful and should be parts of surgical training.

Roles and influence of people who accompany patients on visits to the doctor

OBJECTIVES

To determine the proportion of patients who are accompanied by another person (ie, partner, child, relative, friend) during visits to their doctors; to describe the demographic characteristics and role(s) assumed by the main accompanying person and the nature of the presenting dyads; and to describe the influence of the main accompanying person on the patient-doctor interaction.

DESIGN

Prospective observational survey.

SETTING

Family practices in London, Ont, and surrounding area.

PARTICIPANTS

Eight family physicians completed surveys on 100 consecutive patients attending for both regularly scheduled and emergency visits.

MAIN OUTCOME MEASURES

Roles and influence of the main accompanying person.

RESULTS

Approximately one third (30.4%) of patients were accompanied during visits to their doctors. Children and patients older than 75 years most frequently had another person with them. Most patients (74.1%) were accompanied by one person who most often was female (72.6%) and between the ages of 21 and 40 years (53.6%). The accompanying person's role was most frequently described by doctors as an advocate for the patient (n = 235, 68.5%). If the accompanying person was a child, however, the role was most often described as a silent observer (n = 36, 68.6%). The influence of the main accompanying person on the patient-doctor encounter was usually described as positive (95.1%).

CONCLUSIONS

Physicians report that people accompanying patients usually have a positive influence on medical encounters. Future studies need to include patients' and accompanying persons' perspectives.

Involvement of MAP kinase in the cyclic AMP induction of myelin basic protein gene expression

Cyclic AMP is involved in the differentiation of oligodendrocyte and Schwann cell progenitors into mature myelin producing cells. The involvement of MAP kinases in this pathway was investigated in the D6P2T cell line. This cell line can be induced to display a differentiated phenotype characterized by myelin basic protein gene expression by increased cyclic AMP. Blocking MAP kinase activity with inhibitors of the activating kinase, MEK, by expression of a dominant negative MAP kinase or by expression of the MAP kinase inactivating phosphatase Mkp-1 all blocked the activation of the myelin basic protein promoter in D6P2T cells. In addition, blocking MAP kinase activation during differentiation of an oligodendrocyte-like cell line, CG4, also leads to inhibition of MBP expression. These findings suggest a role for MAP kinase in the cyclic AMP stimulated expression of the myelin basic protein gene during differentiation.

Properties of gamma-frequency oscillations initiated by propagating population bursts in retrohippocampal regions of rat brain slices

1. In the hippocampal formation in vivo, brief periods of gamma-frequency activity follow population bursts called sharp waves. The approximately 200 Hz activity of the sharp wave itself may serve to enhance synaptic connections and the approximately 40 Hz gamma activity has been offered as a mechanism for solving the 'binding' problem. We describe epochs of gamma-frequency activity which follow population spikes evoked by low frequency repetitive extracellular stimuli in retrohippocampal neurons of horizontal rat brain slices. 2. gamma-Frequency activity recorded intracellularly from deep layer neurons of entorhinal cortex, presubiculum and parasubiculum consisted of one action potential correlated with each of the three to five gamma cycles recorded with a proximate field potential electrode. A minority of cells exhibited only sub-threshold gamma-frequency membrane potential oscillations (ranging from 5 to 10 mV). No cells fired more than one spike per gamma cycle under any conditions. 3. The range of synchrony varied from individual cells which showed gamma-frequency firing without corresponding oscillations in close field recordings to field potential recordings of oscillations which were well correlated across regions. The lead or lag between any two retrohippocampal regions was in the direction of the conduction delay for the primary population spike, but typically was less, and approached zero milliseconds for some cycles in most cells. The level of synchrony was stable for particular stimulating conditions (intensity, stimulation rate, stimulus location). 4. The duration of the period of gamma activity had the duration of a slow depolarizing potential which was mediated by NMDA receptor activation. NMDA receptor antagonists or low concentrations of AMPA receptor antagonists reduced the duration of, or completely abolished the slow potential, thereby eliminating the gamma portion of the evoked response. 5. gamma-Frequency firing was eliminated by the GABAA receptor antagonist picrotoxin but small (< 5 mV) membrane potential oscillations remained after focal picrotoxin applications, and these exhibited the voltage dependence of EPSPs. Bath application of thiopental lowered the frequency of gamma oscillations, confirming the involvement of GABAA receptors. 6. The GABAB receptor antagonist 2-hydroxy-saclofen appeared to enhance the gamma activity by increasing the duration of the gamma epoch and increasing the amplitude of individual gamma cycles in field potential recordings. These saclofen-induced cycles were, however, less well synchronized across regions. 7. We show that synchronous gamma (40-100 Hz) activity follows population bursts by deep layer retrohippocampal neurons in undrugged slices from rat brain. Responses from medial entorhinal, parasubicular or presubicular cells were not distinguishable. These events can be initiated by a propagating population spike. We suggest that an NMDA receptor mediated depolarization enables the network of deep layer retrohippocampal neurons to oscillate by providing a sustained excitation, the duration of which determines the duration of the gamma episode. gamma-Frequency firing is primarily the result of GABAA receptor dependent inhibition during this period of sustained depolarization. Recurrent excitation appears to be inconsequential for principal cell firing, but may contribute to interneuron firing.

De novo direct duplication 2 (p12-->p21) with paternally inherited pericentric inversion 2p11.2 2q12.2

We report a 4-year-old girl with a previously undescribed de novo duplication of 2p12->2p21 on the same homologue as a paternally inherited pericentric inversion of region 2p11.2-->2q12.2, resulting in dysmorphic features, cardiac abnormality, cleft palate, respiratory problems, severe growth retardation and developmental delay. This case raises an important question--did the paternal pericentric inversion influence the occurrence of the de novo duplication?

Behavioural, physiological and morphological analysis of a line of apolipoprotein E knockout mouse

Using apolipoprotein E knockout mice derived from the Maeda source [Piedrahita J. A. et al. (1992) Proc. natn. Acad Sci. US.A. 89, 4471 4475], we have studied the influence of apolipoprotein E gene deletion on normal CNS function by neurological tests and water maze learning, hippocampal ultrastructure assessed by quantitative immunocytochemistry and electron microscopy, CNS plasticity, i.e. hippocampal long-term potentiation and amygdaloid kindling, and CNS repair, i.e. synaptic recovery in the hippocampus following deafferentation. In each study there was little difference between the apolipoprotein E knockout mice and wild-type controls of similar age and genetic background. Apolipoprotein E knockout mice aged eight months demonstrated accurate spatial learning and normal neurological function. Synaptophysin and microtubule-associated protein 2 immunohistochemistry and electron microscopic analysis of these animals revealed that the hippocampal synaptic and dendritic densities were similar between genotypes. The induction and maintenance of kindled seizures and hippocampal long-term potentiation were indistinguishable between groups. Finally, unilateral entorhinal cortex lesions produced a marked loss of hippocampal synaptophysin immunoreactivity in both groups and a marked up-regulation of apolipoprotein E in the wild-type group. Both apolipoprotein E knockout and wild-type groups showed immunohistochemical evidence of reactive synaptogenesis, although the apolipoprotein E knockout group may have initially shown greater synaptic loss. It is suggested that either apolipoprotein E is of no importance in the maintenance of synaptic integrity and in processes of CNS plasticity and repair, or more likely, alternative (apolipo)proteins may compensate for the loss of apolipoprotein E in the knockout animals.

High-level expression of RXRalpha and the presence of endogenous ligands contribute to expression of a peroxisome proliferator-activated receptor-responsive gene in hepatoma cells

Genes containing peroxisome proliferator-activated receptor (PPAR) binding sites are both inducible by peroxisome proliferators and expressed in a tissue-specific fashion. A PPAR-responsive reporter gene cotransfected with a PPARalpha expression vector was highly expressed in H4IIEC3 hepatoma cells. Addition of clofibrate resulted in a modest further induction of the reporter gene. In CV-1 cells, high expression of the reporter required the addition of clofibrate. H4IIEC3 cells had higher levels of retinoid X receptor (RXRalpha) than CV-1 cells; cotransfection of CV-1 cells with PPARalpha plus RXRalpha expression plasmids abolished the cell line difference in basal and clofibrate-stimulated expression of the reporter. Lipid extracts of hepatoma cells or of liver or kidney stimulated expression of the reporter; extracts of CV-1 cells were far less effective. Chromatographic analysis of these extracts revealed high levels of three fractions of lipid in liver and H4IIEC3 cells that were lower in CV-1 cells. We conclude that (1) in cells expressing high levels of both RXRs and PPARalpha, such as hepatocytes and kidney cells, these factors are constitutively active; (2) activators of PPARalpha may increase its ability to form heterodimers with RXRs when the latter are limiting; and (3) hepatoma cells, liver, and kidney contain lipid-extractable compounds capable of activating PPARalpha.

Mobilization of peripheral blood progenitor cells by Betafectin PGG-Glucan alone and in combination with granulocyte colony-stimulating factor

Betafectin PGG-Glucan, a novel beta-(1,6) branched beta-(1,3) glucan purified from the cell walls of Saccharomyces cerevisiae, has been shown to synergize with myeloid growth factors in vitro and to enhance hematopoietic recovery in myelosuppressed mice and primates. Here we report that PGG-Glucan is also capable of mobilizing peripheral blood progenitor cells (PBPC). PGG-Glucan (0.5 mg/kg to 16 mg/kg) was administered intravenously to C3H/HeN male mice and blood collected at times ranging from 30 min to seven days after injection. Based on granulocyte-macrophage colony-forming cell (GM-CFC) levels, peak mobilization occurred 30 min after a 2 mg/kg PGG-Glucan dose. At this time GM-CFC numbers in PGG-Glucan-treated mice were approximately fourfold greater than in saline-treated control mice. A second, smaller wave of GM-CFC mobilization (approximately twofold increase) also occurred on days 4 and 5 after PGG-Glucan treatment. Mobilization was not associated with the induction of alpha-chemokines, which have recently been reported to induce rapid progenitor cell mobilization. Competitive repopulation experiments performed in irradiated female C3H/HeN mice revealed that, at three months after transplantation, more male DNA was present in bone marrow, splenic, and thymic tissues from animals transplanted with cells obtained from mice 30 min after a 2 mg/kg PGG-Glucan dose than in tissues from animals transplanted with cells obtained from saline-treated mice. Additional experiments evaluated the mobilization effects of PGG-Glucan (2 mg/kg) administered to mice which had been pretreated for three consecutive days with G-CSF (125 microg/kg/day). When blood was collected 30 min after PGG-Glucan treatment, the number of GM-CFC mobilized in combination-treated mice was additive between the number mobilized in mice treated with G-CSF alone and the number mobilized in mice treated with PGG-Glucan alone. These studies demonstrate that: A) PGG-Glucan can rapidly mobilize PBPC; B) the kinetic pattern of PGG-Glucan-induced mobilization is different from that of the CSFs; C) the reconstitutional potential of PGG-Glucan mobilized cells is greater than that of steady-state PBPC, and D) PGG-Glucan can enhance G-CSF-mediated PBPC mobilization.