Health practices and mental health revisited

The relationships of seven health practices with a measure of mental well-being were explored in a sample of 490 university students. Mental well-being was associated with moderate exercise and regular sleep.

Contribution of pancreatic hormone responses to the elevation in carbohydrate metabolism with reduced PaO2

Reduced O2 availability, as might occur under some physiological and pathological conditions, stimulates insulin and glucagon release and increases glucose fluxes and muscle carbohydrate metabolism. The aim of this study was to determine the role of reduced PO2, independent of changes in glucagon and insulin. In six dogs, in paired studies separated by 2 wk, glucagon and insulin levels were fixed throughout by infusion of somatostatin with basal intraportal glucagon and insulin replacement. A control period was followed by 90 min of breathing 21% (NO) or 8% (LO) O2. Isotopic and arteriovenous methods were used to assess carbohydrate metabolism. Measured variables were constant over time in NO. Arterial PO2 (Pao2) was approximately 100 mmHg in NO and approximately 30 mmHg in LO, resulting in a 50% fall in O2 content. Insulin, glucagon, and catecholamine levels were similar in NO and LO. Cortisol was significantly increased in LO. Arterial glucose was unchanged in both groups. In the last 45 min of the experimental period in LO, 1) glucose production (14 +/- 1 to 18 +/- 1 mumol.kg-1.min-1), glucose disappearance (15 +/- 1 to 17 +/- 1 mumol.kg-1.min-1), and net hepatic glucose output (11 +/- 1 to 15 +/- 1 mumol.kg-1.min-1) rose, 2) limb pyruvate oxidation (11 +/- 2 to 24 +/- 5 mumol/min) and estimated glycogenolysis (9 +/- 3 to 42 +/- 9 mumol/min) increased, 3) percentages of CO2 from limb pyruvate and glucose increased, and percentage of lactate from blood glucose decreased, and 4) arterial blood lactate was approximately 100% more, although net limb and hepatic lactate balances were unaltered, which suggests that neither liver nor muscle is the source of increased blood lactate. Comparison of these results with our previous study [Zinker et al. Am. J. Physiol. 266 (Endocrinol. Metab. 29): E921-E929, 1994] shows that the response to reduced PaO2, although present, is reduced when glucagon and insulin levels are fixed at basal. The majority of stimulation of glucose production by decreased PaO2 is still present when pancreatic hormones are clamped at basal, while the response by the hindlimb tissues is greatly reduced.

Interaction of fimbriated and nonfimbriated strains of unencapsulated Haemophilus influenzae with human respiratory tract mucus in vitro

Adherence to mucus may influence bacterial colonization of the respiratory tract. Clinical isolates of nontypable Haemophilus influenzae (NTHi) from the respiratory tract are often fimbriated. We wondered whether fimbriated strains have a different adherence from related nonfimbriated strains. A microtitre plate assay has been developed to study adherence of nontypable H. influenzae to mucus. Wells were coated by incubation either with sol phase of sterile mucoid secretions or with purified preparations of mucins. Two laboratory pairs of fimbriated (F+) and nonfimbriated (F-) nontypable H. influenzae, and six fresh clinical isolates of fimbriated nontypable H. influenzae each with nonfimbriated partners derived by serial passage on agar, were cultured to mid-log phase, washed, and then added to the wells. They were then incubated at 37 degrees C for 30 min before washing to remove unbound bacteria. Adherent bacteria were desorbed by agitation with 0.5% Tween 80 and a viable count performed. The two fimbriated laboratory strains (n = 12 and n = 17), and 5 of the 6 fimbriated clinical isolates were more adherent to sol phase than their respective nonfimbriated partners. Two nonfimbriated clinical isolates were more adherent to plastic than their fimbriated partners. A fimbriated laboratory strain was more adherent than its nonfimbriated partner both to a purified preparation of high molecular mass mucin and to the glycopeptide fraction of the same. We conclude that fimbriated strains of nontypable H. influenzae have increased adherence to sol phase of mucus and purified human respiratory tract mucin. The interactions of fimbriae with mucus are likely to be complex, and may involve both nonspecific and specific interactions.

Bronchitis

Acute bronchitis in previously fit individuals is a common condition that is usually mild and self limiting. Chronic bronchitis remains a common cause of morbidity and mortality, and the cost to the nation due to lost working days and to health services is enormous. Cigarette smoking is the major etiologic factor, although exacerbations may be caused by viruses, environmental pollutants, allergic responses, and bacterial infections. New insights into the underlying basic mechanisms of bronchial inflammation are being made. Antibiotics are commonly used to treat exacerbations, although evidence of efficacy is sometimes lacking. Some patients may be prone to recurrent exacerbations and this influences their chance of recovery. Clinical trials must include an assessment of the severity of the exacerbation, and protocols would be improved by increased definition of the type of patient being enrolled and by inclusion of more detailed measures of benefit. Influenza and pneumococcal vaccination should be encouraged in appropriate patients.

The translocation, folding, assembly and redox-dependent degradation of secretory and membrane proteins in semi-permeabilized mammalian cells

We describe here a semi-permeabilized cell-system which reconstitutes the efficient synthesis, translocation, folding, assembly and degradation of membrane and secretory proteins. Cells grown in culture were treated with the detergent digitonin which selectively permeabilized the plasma membrane leaving the cellular organelles, such as the endoplasmic reticulum (ER) and trans-Golgi network intact. These permeabilized cells were added to an in vitro translation system, either wheatgerm or reticulocyte lysate, supplemented with RNA coding for either membrane or secretory proteins. Efficient translocation and modification of proteins by these cells was demonstrated by protease protection, photocross-linking of nascent chains to components of the translocation apparatus and by post-translational modifications such as glycosylation or hydroxylation. A comparison was made between the ability of semi-permeabilized cells and microsomal vesicles to fold and assemble proteins. The results show that the intact ER within these cells can assemble proteins much more efficiently than vesicularized ER. Furthermore, the semi-permeabilized cells carried out the redox-dependent degradation of tissue-type plasminogen activator. This system has all the advantages of conventional cell-free systems, including speed and, importantly, the ability to manipulate the components of the assay, while retaining intracellular organelles and, therefore, allowing cellular processes to occur as they would in the intact cell.

Epidemiology of AIDS

This presentation provides an overview of the epidemiology of human immunodeficiency virus (HIV) disease in the United States, followed by a discussion highlighting the extent of HIV disease globally.

Interaction of fimbriated and nonfimbriated strains of unencapsulated Haemophilus influenzae with human respiratory tract mucus in vitro

Adherence to mucus may influence bacterial colonization of the respiratory tract. Clinical isolates of nontypable Haemophilus influenzae (NTHi) from the respiratory tract are often fimbriated. We wondered whether fimbriated strains have a different adherence from related nonfimbriated strains. A microtitre plate assay has been developed to study adherence of nontypable H. influenzae to mucus. Wells were coated by incubation either with sol phase of sterile mucoid secretions or with purified preparations of mucins. Two laboratory pairs of fimbriated (F+) and nonfimbriated (F-) nontypable H. influenzae, and six fresh clinical isolates of fimbriated nontypable H. influenzae each with nonfimbriated partners derived by serial passage on agar, were cultured to mid-log phase, washed, and then added to the wells. They were then incubated at 37 degrees C for 30 min before washing to remove unbound bacteria. Adherent bacteria were desorbed by agitation with 0.5% Tween 80 and a viable count performed. The two fimbriated laboratory strains (n = 12 and n = 17), and 5 of the 6 fimbriated clinical isolates were more adherent to sol phase than their respective nonfimbriated partners. Two nonfimbriated clinical isolates were more adherent to plastic than their fimbriated partners. A fimbriated laboratory strain was more adherent than its nonfimbriated partner both to a purified preparation of high molecular mass mucin and to the glycopeptide fraction of the same. We conclude that fimbriated strains of nontypable H. influenzae have increased adherence to sol phase of mucus and purified human respiratory tract mucin. The interactions of fimbriae with mucus are likely to be complex, and may involve both nonspecific and specific interactions.

Reliability of stomach temperature changes in determining feeding characteristics of seabirds

We examined the accuracy of stomach temperature archival units (STAUs), which are typically used to determine feeding activity in marine endotherms, with regard to determination of the time of prey ingestion as well as the number of prey items ingested and their masses. Units were deployed in nine species of free-living seabirds, where feeding conditions were uncontrolled, eight species of captive seabirds, where feeding conditions could be partially controlled, and in laboratory stomach simulations, where variables could be strictly controlled. The quality of data obtained on the timing of feeding, the mass ingested and the number of prey items ingested was subject to two main sources of error (i) those induced by changes in animal activity and (ii) those resulting from the physical form of the STAUs themselves. Animal activity factors considered important included the following: variability in (a) body temperature, (b) stomach blood perfusion, (c) consistency of stomach contents and (d) stomach churning and changes in body orientation. The physical form (size and buoyancy) of the STAU affected the location of the unit within the stomach, and thus the likelihood that ingested prey comes into contact with the sensor. The timing of prey ingestion can generally be determined accurately; however, considerable errors in mass estimates can occur if data acquired using STAUs are not critically assessed. An understanding of these sources of errors will allow researchers to construct STAUs appropriate to the species being studied and to analyze data critically so that errors are reduced.

Current prescribing in primary care in the UK. Effects of the indicative prescribing scheme and GP fundholding

The costs of drugs prescribed in primary care in the UK continue to rise despite a variety of government initiatives. Two of the major initiatives are considered here in detail: the Indicative Prescribing Scheme (IPS), and general practitioner (GP) fundholding, both of which began in 1991. Other more recent initiatives are also described, including the selected list, the Pharmaceutical Pricing Regulatory Scheme and the move to relicense drugs for nonprescription sale. The IPS has generally failed to control the rise in drug costs because of unrealistic targets, organisational difficulties (including the lack of adequate data to set budgets properly) and because there was neither incentive nor penalty to encourage compliance on the part of the GP. The IPS stresses cost containment, and makes little allowance for the consideration of quality of appropriateness of prescribing. Despite this disappointment, the IPS is continuing, and the future of the scheme is discussed here. GP fundholding, in contrast, has reduced the rate of rise of drug costs in participating GP practices, although it has not actually reduced drug costs. There have been a number of studies of this model, which are discussed here. The clear financial incentive to fundholders encourages them to restrain drug costs. Attempts to extend similar incentives to nonfundholding GPs are also described. Although there is a commitment on the part of the government to encourage and make use of data about economic evaluations of drug therapy and other medical interventions, so far the emphasis has been exclusively on cost containment. In this paper, we consider possible mechanisms by which this might be improved.

The ciliary transportability of sputum is slow on the mucus-depleted bovine trachea

Mucus retention in the lungs is a feature of several chest diseases. It is unclear to what extent suboptimal mucus transportability is responsible for the poor clearance of lung secretions. We described a new model, the mucus-depleted bovine trachea, for measurement of the ciliary transportability of respiratory mucus. Mucus depletion was demonstrated microscopically and functionally, and it was accomplished by simple physical means without impairing ciliary action. Control mucus from the tracheas of humans and animals was transported rapidly on this system. However, sputum from 54 patients with bronchiectasis was transported slowly, at a mean of 15% of the rate of control mucus. There was no correlation between sputum transportability and either purulence or the presence of Pseudomonas aeruginosa. This work suggests that there is a serious defect in the ciliary transportability of sputum that is unrelated to the presence of infection. The model should allow in vitro assessment of agents designed to aid mucociliary clearance.

Cell cycle kinetics in pterygium at three latitudes

The cell cycle kinetics of 93 specimens of pterygial tissue, as well as 19 specimens of normal conjunctiva, from patients at three sites representing three different latitudes (Singapore, 1 degree; Hong Kong, 22 degrees; and Little Rock, Arkansas, 34 degrees) were evaluated by flow cytometry. The results showed no difference in cellular proliferation patterns between pterygial and conjunctival tissue at any of the sites, suggesting that pterygium is not a disorder of excess cellular proliferation. Transmission electron microscopy showed extracellular matrix to be a prominent component of pterygium. Cellular proliferation patterns of primary and recurrent pterygium were not significantly different from each other. Factors associated with increased incidence of pterygium included male sex, outdoor occupation, and advanced age.

Core and comprehensive health care services: 1. Introduction to the Canadian Medical Association's decision-making framework

The CMA's decision-making framework on core (i.e., publicly funded) and comprehensive health care services emphasizes flexibility and recognizes three levels at which decisions can be made: between patients and physicians (micro), in the community or by society (meso) and by governments (macro). Three major content dimensions are considered quality of care (e.g., effectiveness, appropriateness and efficiency of health care services), ethics (e.g., decisions that reflect fairness and acceptability to patients and physicians) and economics (e.g., measurement of service costs against economic benefits in a time of severe economic restraint). There are challenges in applying the framework; however, by providing decision-makers with the knowledge and tools needed to assist in the process, it is hoped that the first and foremost concern will continue to be the quality of patient care so highly valued by Canadians.

Ciliary disorientation in patients with chronic upper respiratory tract inflammation

Random ciliary orientation was recently described as a possible variant of primary ciliary dyskinesia (PCD). The cilia have normal ultrastructure and nearly normal ciliary beat frequency (CBF) but lack efficacy because the beat direction is disoriented. However, delayed mucociliary clearance (MCC), transitory changes in ultrastructure, and slowed CBF can all occur in the presence of inflammation. This study investigated groups of patients with upper respiratory tract inflammation caused by infection to assess whether ciliary disorientation was present and its relation to MCC. The study population consisted of 10 healthy nonatopic nonsmoking volunteers, 15 patients with idiopathic bronchiectasis and chronic mucopurulent sinusitis, 12 patients with cystic fibrosis, and two patients with the clinical features of PCD but normal CBF and ciliary ulstrastructure. Ciliary disorientation was significantly (p < 0.05) increased in the three patient groups compared with the volunteers, being greatest in the two patients with the clinical features of PCD and in bronchiectasis patients with P. aeruginosa, and was positively correlated (r = 0.9) with MCC but not with CBF. Treatment of one patient with antibiotics and topical corticosteroids for a prolonged period resulted in ciliary disorientation returning to normal. Ciliary disorientation may therefore occur secondary to inflammation caused by infection, and the study suggests that ciliary disorientation rather than ultrastructural abnormalities or slow CBF results in delayed MCC.

Rapid identification of 4-hydroxy-2-alkylquinolines produced by Pseudomonas aeruginosa using gas chromatography-electron-capture mass spectrometry

The 4-hydroxy-2-alkylquinolines and their N-oxides are secondary metabolites produced by Pseudomonas aeruginosa which inhibit the growth of a number of Gram-positive organisms including Staphylococcus aureus. To facilitate the identification of these compounds in biological fluids, we have developed a rapid profiling system based on gas chromatography-electron-capture mass spectrometry of the O-bistrifluoromethylbenzoyl derivatives. Using the technique, over twenty hydroxyalkylquinolines have been identified from a culture obtained from a strain of P. aeruginosa obtained from a patient with severe bronchiectasis.

The use of ultra-low-dose aprotinin to reduce blood loss in cardiac surgery

One hundred patients due to undergo primary cardiac surgery were prospectively randomized to receive aprotinin or placebo. In the aprotinin group, 250,000 kallikrein inhibitory units (KIU) of aprotinin were added to the cardiopulmonary bypass prime solution. A further 250,000 KIU of aprotinin were infused intravenously over 30 minutes immediately before the start of cardiopulmonary bypass. The control group received 0.9% saline in equal volumes at identical times. The study was designed to have a 90% chance of demonstrating a 30% reduction in blood loss. No significant differences were found between the two groups. The median blood loss in the aprotinin group was 750 mL (interquartile range 556 to 1025 mL, 95% confidence interval 600 to 800 mL). In the control group, the median blood loss was also 750 mL (interquartile range 500 to 988 mL, 95% confidence interval 625 to 925 mL). In the aprotinin group, 12 patients received postoperative autotransfusion of shed mediastinal blood of median volume of 665 mL (interquartile range 500 to 925 mL, 95% confidence interval 450 to 1000 mL). In the control group, 14 patients received postoperative autotransfusion of mediastinal blood of median volume of 663 mL (interquartile range 600 to 800 mL, 95% confidence interval 600 to 700 mL). Five patients in the aprotinin group and seven patients in the control group required postoperative homologous blood transfusion. Reassessment of inclusion criteria showed a 19% reduction in blood loss in patients undergoing only aortocoronary bypass receiving aprotinin compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction of pneumolysin-sufficient and -deficient isogenic variants of Streptococcus pneumoniae with human respiratory mucosa

Streptococcus pneumoniae is the most common cause of community-acquired pneumonia, and pneumolysin, a hemolytic toxin, is thought to be an important virulence factor. We have studied the interaction of a pneumolysin-sufficient type II S. pneumoniae strain (PL+) and an otherwise identical pneumolysin-deficient derivative (PL-) with human respiratory mucosa in an organ culture with an air interface for up to 48 h. Ciliary beat frequency (CBF) was measured by a photometric technique, and adherence to and invasion of the epithelium were assessed by scanning and transmission electron microscopy. PL+ and PL- caused a progressive fall in CBF compared with the control which became significant (P < 0.01) at 24 h for PL+ and at 48 h for PL-. At 24 h, there was a significant increase in the percentage of the mucosa of the organ culture that was damaged for PL+ compared with the control (P < 0.01) and PL- (P < 0.02). At 48 h, there was a significant increase in mucosal damage for both PL+ (P < 0.005) and PL- (P < 0.05) compared with the control. At 24 and 48 h, PL+ and PL- adhered predominantly to mucus and damaged cells. PL+ infection alone caused separation of tight junctions between epithelial cells, and at 48 h PL+ cells were adherent to the separated edges of otherwise healthy unciliated cells. PL+ and PL- both caused damage to the epithelial cell ultrastructure. S. pneumoniae infection caused patchy damage to the respiratory mucosa and a lowered CBF. These changes were more severe and occurred earlier with the pneumolysin-sufficient variant.