Lung function testing tutorial: pitfalls for the unwary when performing spirometry

Spirometry is a simple; reliable; and informative tool in the assessment of respiratory function. It has many indications in both the diagnosis and monitoring of respiratory disease; but in Africa it could be most immediately useful in quantifying the unknown burden of chronic obstructive pulmonary disease (COPD) related to indoor air pollution as well as the burden of asthma. In order to ensure that spirometry is reliable; quality control is essential. In particular; normal values must be regionally appropriate; technique must be well taught; and equipment must be properly calibrated. In 2005; the ATS/ERS Task Force (American Thoracic Society and European Respiratory Society) issued guidelines aimed at integrating existing international guidelines. Good standards for spirometry will result in a useful; narrow range of normal values for a population and abnormalities in lung function will be easily detected. The aim of this article is to address the key issues regarding basic spirometry standards; and to highlight the common pitfalls

Saccadometry: the possible application of latency distribution measurement for monitoring concussion.

Premature return to play after concussion may have debilitating or even fatal consequences. Computerised neuropsychological test batteries are widely used to monitor recovery, but none meet all specified criteria. One possible alternative is to measure saccadic reaction time or latency. Latency reflects the operation of cerebral decision mechanisms, and is strongly influenced by many agents that impair cortical function. A portable, micro-miniature device (saccadometer) was used to record the eye movements of amateur boxers before and after competitive bouts. Individual latency distributions were significantly affected after blows to the head, though the effects seemed to be reversible, with recovery over a few days. This quantitative, objective and easy to use technique should perhaps be deployed more widely to evaluate its potential in monitoring the effects of sports-related head injuries.

Destructive osteoarthritis after delayed diagnosis of tuberculosis.

Osteoarticular tuberculosis rarely occurs in developed countries. Initial symptoms are often overlooked and the diagnosis is frequently delayed for several months. Thus, despite available diagnostic tools and accessible treatment, destruction of affected joints remains a complication of non-vertebral osteoarticular tuberculosis even in industrialized countries. We report a patient from Cleveland, Ohio, USA, in whom the delayed diagnosis of tuberculous osteoarthritis led to severe destruction of the left knee and finally, after superinfection with Staphylococcus aureus, to an above-the-knee amputation. The epidemiology, presentation, diagnosis and treatment of nonvertebral tuberculous osteoarthritis are discussed.

Design and implementation of an inpatient disease management program.

OBJECTIVE: To describe the development and implementation of an inpatient disease management program. STUDY DESIGN: Prospective observational study. PATIENTS AND METHODS: On the basis of opportunities for improving quality or efficiency of inpatient and emergency department care, 4 diagnoses, including congestive heart failure (CHF), gastrointestinal hemorrhage, community-acquired pneumonia and sickle-cell crisis were selected for implementation of a disease management program. For each diagnosis, a task force assembled a disease management team led by a "physician champion" and nurse care manager and identified opportunities for improvement through medical literature review and interviews with caregivers. A limited number of disease-specific guidelines and corresponding interventions were selected with consensus of the team and disseminated to caregivers. Physician and nurse team leaders were actively involved in patient care to facilitate adherence to guidelines. RESULTS: For quarter 2 to 4 of 1997, there were improvements in angiotensin-converting enzyme inhibitor use, daily weight compliance, assessment of left ventricular function, hospital costs, and length of stay for care-managed patients with CHF. Differences in utilization-related outcomes persisted even after adjustment for severity of illness. For the other 3 diagnoses, the observational period was shorter (quarter 4 only), and hence preliminary data showed similar hospital costs and length of stay for care-managed and noncare-managed patients. CONCLUSIONS: An interdisciplinary approach to inpatient disease management resulted in substantial improvements in both quality and efficiency of care for patients with CHF. Additional data are needed to determine the program's impact on outcomes of other targeted diagnoses.

Social enhancement of fitness in yellow-bellied marmots.

The yellow-bellied marmot (Marmota flaviventris) is a social, ground-dwelling squirrel that lives either individually or in kin groups of from two to five adult females. Philopatry and daughter recruitment lead to the formation and persistence of matrilines at habitat sites. By using 37 years of demographic data for 12 habitat sites, we could determine long-term trends in the effects of group size on two measures of fitness, survivorship and net reproductive rate, which otherwise are obscured by annual fluctuations in these measures. Both size and number of matrilines varied among sites and survivorship and net reproductive rate varied among sites and among matriline sizes. The role of social organization was explored further by examining the effect of matriline size, averaged over all years and sites, on fitness. For both survivorship and net reproductive rate the relationship with matriline size was curvilinear. Fitness increased with the increase in matriline size and then decreased in the largest groups. Decreased fitness in matrilines of four or five was associated with agonistic behavior, a large number of 2-year-old females in the social group, and reproductive suppression. There is no evidence that females acted to increase their fitness by increasing indirect fitness; i.e., by assisting relatives, but attempted to increase direct fitness. Direct fitness increased when mortality and fission of large matrilines reduced group size and the surviving females increased reproduction.

Climate change is affecting altitudinal migrants and hibernating species.

Calendar date of the beginning of the growing season at high altitude in the Colorado Rocky Mountains is variable but has not changed significantly over the past 25 years. This result differs from growing evidence from low altitudes that climate change is resulting in a longer growing season, earlier migrations, and earlier reproduction in a variety of taxa. At our study site, the beginning of the growing season is controlled by melting of the previous winter's snowpack. Despite a trend for warmer spring temperatures the average date of snowmelt has not changed, perhaps because of the trend for increased winter precipitation. This disjunction between phenology at low and high altitudes may create problems for species, such as many birds, that migrate over altitudinal gradients. We present data indicating that this already may be true for American robins, which are arriving 14 days earlier than they did in 1981; the interval between arrival date and the first date of bare ground has grown by 18 days. We also report evidence for an effect of climate change on hibernation behavior; yellow-bellied marmots are emerging 38 days earlier than 23 years ago, apparently in response to warmer spring air temperatures. Migrants and hibernators may experience problems as a consequence of these changes in phenology, which may be exacerbated if climate models are correct in their predictions of increased winter snowfall in our study area. The trends we report for earlier formation of permanent snowpack and for a longer period of snow cover also have implications for hibernating species.

Does sociality drive the evolution of communicative complexity? A comparative test with ground-dwelling sciurid alarm calls.

While sociality has been hypothesized to drive the evolution of communicative complexity, the relationship remains to be formally tested. We derive a continuous measure of social complexity from demographic data and use this variable to explain variation in alarm repertoire size in ground-dwelling sciurid rodents (marmots, Marmota spp.; prairie dogs, Cynomys spp.; and ground squirrels, Spermophilus spp.). About 40% of the variation in alarm call repertoire size was explained by social complexity in the raw data set. To determine the degree to which this relationship may have been influenced by historical relationships between species, we used five different phylogenetic hypotheses to calculate phylogenetically independent contrasts. Less variation was significantly explained in contrast-based analyses, but a general positive relationship remained. Social complexity explained more variation in alarm call repertoire size in marmots, while sociality explained no variation in repertoire size in prairie dogs and no variation in phylogenetically based analyses of squirrels. In most cases, substantial variation remained unexplained by social complexity. We acknowledge that factors other than social complexity, per se, may contribute to the evolution of alarm call repertoire size in sciurid rodents, and we discuss alternative hypotheses. Our measure of social complexity could be used by other researchers to test explicit evolutionary hypotheses that involve social complexity.

Resting and field metabolic rates of adult male yellow-bellied marmots, Marmota flaviventris.

Resting metabolic rate (RMR) and field metabolic rate (FMR) of wild-caught males were estimated from oxygen consumption and the doubly-labeled water method, respectively. The average FMR:RMR ratio of 6.9 was much greater than ratios reported for other mammals. Total FMR (kJ/day) increased and specific RMR (kJ/kg/day) decreased with time. Neither total RMR nor specific FMR were significantly related to time. The decrease in specific RMR may result from a circannual decrease in maintenance expenditure and a seasonal increase in body mass. Total FMR may increase through the season as conditions for male activity become more favorable.

Accessory function and properties of monocytes from healthy elderly humans for T lymphocyte responses to mitogen and antigen.

The waning of cell-mediated immunity during aging has been attributed primarily to defects in T lymphocyte properties and functions. We assessed the potential contribution of accessory dysfunction of monocytes from the elderly on responses of T cells to phytohemagglutinin (PHA) and to tetanus toxoid after in vivo boosting. Accessory function of monocytes from the elderly subjects for T lymphocyte responses to tetanus toxoid was comparable to the young. Expression of the cytokines interleukin-1, interleukin-6 and tumor necrosis factor, the cell adhesion molecules ICAM-1 and LFA-3 and the class II major histocompatibility molecule HLA-DR by monocytes from the elderly and young subjects was similar. T lymphocytes from the elderly responded poorly to PHA. Monocytes from the elderly had a decreased accessory function for PHA-stimulated T cells from young, third donors. Thus, although many accessory properties of monocytes from the elderly are normal, the monocyte and T lymphocyte defects in the elderly for mitogen may represent interactive factors in cell-mediated immunity during aging.

Transient normalization of lymphocyte blastogenic and specific antibody responses following boosting of healthy elderly subjects with tetanus toxoid.

The diminished in vitro blastogenic response of lymphocytes from the elderly to mitogenic stimuli is cited as evidence of immunosenescence, but the response to specific microbial antigens has not been well characterized. We measured the response to tetanus toxoid before and after boosting in young and elderly subjects. Elderly subjects (age > or = 70) and young controls (age < 35) were subjected to clinical, laboratory, and nutritional evaluation to ensure a cohort of healthy subjects. Responses of lymphocytes from the elderly to the mitogens phytohemagglutinin and concanavalin A were markedly diminished compared to those from the young. For all subjects, the average in vitro blastogenic response to tetanus toxoid of lymphocytes from elderly subjects (n = 23) was significantly diminished compared to young controls (n = 23; 31,985 +/- 4502 vs 14,411 +/- 3714 cpm, p < .01). Following boosting with tetanus in those subjects in whom boosting with tetanus toxoid was indicated, blastogenesis was comparable between elderly (n = 17) and young subjects (n = 7; 38,078 +/- 11,451 vs 42,103 +/- 9247 cpm). The boosted response to tetanus apparently was not sustained, since in the subset of subjects with a history of tetanus immunization in the past 10 years, the response of the elderly was much less than that of the young. Thus, a cohort of healthy elderly with diminished blastogenic responses to mitogens was capable of at least a transiently normal response to tetanus post boosting.

Factors affecting oxygen consumption in wild-caught yellow-bellied marmots (Marmota flaviventris).

1. All age groups gained mass during the active season, but mass-gain of adult females was delayed during lactation. 2. The relationship of body mass to metabolic rate varied widely; when the relationship was significant, R2 varied from 10.3 to 72.6%. Body mass affects VO2 more during lactation than at any other period. 3. Mean VO2 of adult males was higher in June than that of adult, non-lactating females. 4. VO2 of reproductive females was significantly higher during lactation than during gestation or postlactation because specific VO2 varied. Specific VO2 of non-reproductive females declined over the active season. 5. Specific VO2 of all age groups declined between the premolt and postmolt periods. The reduced maintenance costs can contribute 20-46% to daily growth. 6. Observed VO2 was lower than the value predicted from intraspecific or interspecific Bm:M regressions. 7. VO2 of wild-caught marmots was lower than that of marmots maintained in the laboratory, probably because of dietary differences. 8. Because basal metabolism is a stage on a food-deprivation curve, we suggest that basal metabolic rate is not an appropriate measure of the metabolic activity of free-ranging animals.

Treatment of cryptosporidiosis with paromomycin. A report of five cases.

Cryptosporidiosis continues to be one of the most devastating complications of the acquired immunodeficiency syndrome, causing severe, chronic diarrhea that is largely refractory to treatment. More than 60 drugs have been tried in the treatment of cryptosporidiosis, none of which have been consistently successful. We describe the successful treatment of cryptosporidiosis in five patients with acquired immunodeficiency syndrome with oral paromomycin at a dose of 1500 to 2000 mg/d. All five patients had resolution of symptoms and normalization of bowel movements, although one patient later relapsed while receiving paromomycin. Three of five patients cleared Cryptosporidium from the stool. Paromomycin is a promising therapy for cryptosporidiosis in acquired immunodeficiency syndrome and further prospective clinical trials are warranted.

Factors affecting corticosteroid concentrations in yellow-bellied marmots.

1. Bound and total corticosteroid concentrations of yellow-bellied marmots (Marmota flaviventris) were lowest in May after emergence from hibernation and peaked in August prior to immergence. 2. Total corticosteroids were affected by age but not by sex or reproductive status. 3. There was no consistent relationship between measures of population density and concentrations of corticosteroids; when a significant relationship occurred, only 22-34% of the variation was explained. 4. Social status and social behavior were the major factors affecting corticosteroid concentrations.

Social dynamics of mammals: Reproductive success, kinship and individual fitness.

Apparent altruism, in which an individual seemingly decreases its evolutionary fitness by assisting others, can confer benefits if the individual assists kin. Thus, an animal can increase its total or inclusive fitness by producing offspring (direct fitness) and/or helping kin to reproduce (indirect fitness). Although kin selection has been suggested as the mechanism underlying the formation of mammalian societies, many species act as if they attempt to maximize the direct fitness component of their inclusive fitness.

Promoting the use of car safety devices for infants: an intensive health education approach.

Efforts to promote the use of infant car seats through health education techniques have been disappointing when strict criteria for evaluation are used. Low-income families were targeted and were provided with educational sessions in the prenatal, postdelivery , and infant follow-up periods. Free car seats were given to 179 clients. Base-line and follow-up observations were performed at 4 months after delivery. The proportion of correctly restrained infants increased from 9% to 38%. The number of infants who were lap held decreased from 38% to 18%. The proportion of clients who had an approved car seat but who were using it incorrectly increased from 11% to 23%.

Hematological values for free-ranging yellow-bellied marmots.

1. Hemoglobin, packed cell volume, erythrocytes, leucocytes, MCV, MCH and MCHC were determined for a population of Marmota flaviventris over a period of seven years. 2. There was no significant difference in hematology among years, between sexes, or between seasons for adults and yearlings. 3. Early season juveniles had significantly lower PCV, Hb and erythrocyte counts than did late season juveniles. There were no significant differences in hematological values among adults, yearlings and late season juveniles. 4. Juveniles had significantly lower leucocycte counts than adults and yearlings. 5. PCV of marmots responds to acclimatization. 6. Hematological values of scuirids are adaptive to environmental factors such as hypoxia of burrows and high altitude, temperature and metabolic rate. 7. PCV of yellow-bellied marmots evidences an adaptive response to high altitude when compared to the closely-related woodchuck, M. monax.

Genetic variation in social mammals: the marmot model.

The social substructure and the distribution of genetic variation among colonies of yellow-bellied marmots, when analyzed as an evolutionary system, suggests that this substructure enhances the intercolony variance and retards the fixation of genetic variation. This result supports a traditional theory of gradual evolution rather than recent theories suggesting accelerated evolution in social mammals.