Traditional Recommendations Research Articles

Yellow fever immunizations: Indications and risks

The yellow fever vaccine plays an essential role in protecting humans from yellow fever, and millions of doses are administered each year. The attenuated live-virus vaccine has long been considered to be among the safest and most effective vaccines. Newly recognized rare, but sometimes fatal, adverse events associated with the vaccine have prompted scrutiny of the traditional recommendations for use of the vaccine and have raised questions about their pathogenesis. This paper describes the adverse events associated with the vaccine, reviews postulated reasons for the recent recognition of these events, discusses key research questions that need to be addressed in trying to understand their origin and risk factors, and reviews current indications for the use of the vaccine. Knowledge of the epidemiology of yellow fever is necessary to make informed recommendations. Current surveillance is inadequate to provide a precise exposure risk for most travelers.

Self-monitoring of blood glucose significantly improves metabolic control in patients with type 2 diabetes mellitus: the Auto-Surveillance Intervention Active (ASIA) study

Self monitoring of blood glucose (SMBG) in type 2 diabetes is a topic of current interest (imbalance between increased health-care costs and improvement in compliance with treatment and diet). An open label randomized prospective study was designed to compare changes in metabolic control over 6 months in patients managed with usual recommendations alone (conventional assessment group) or combined with SMBG. Patients not treated with insulin or previously self monitored, 40 to 75 years of age, with a diagnosis of type 2 diabetes > 1 year and standardized HbA(1c) level > =7.5 and< =11% were randomized to either a control group or SMBG group. They were followed up every 6 weeks over 24 weeks. Patients in the SMBG group were given the same device (Ascensia Esprit Discmeter, Bayer) and were required to perform at least 6 capillary assays a week (3 different days of the week, including weekend). Management of patients was standardized, including drugs, diet and physical activity. The primary efficacy criterion was change in HbA(1c) level in Intent To Treat (ITT) patients. Assays were performed at baseline, at 3 and 6 months using the calibrated DCA 2000(R) device (Bayer). Two hundred sixty five general practitioners randomized 988 patients (ITT Population), but 689 patients were evaluable for the primary criterion. At the endpoint, HbA(1c) was lower in the SMBG group (8.1 +/- 1.6%) than in the conventional treatment group (8.4 +/- 1.4%, P=0.012). The change in HbA(1c) levels between baseline and endpoint was classified into two classes: improvement if a change > 0.5% occurred, stability or worsening in case of a change< =0.5%; 57.1% of patients in the SMBG group vs 46.8% in the control group had an improvement in HbA(1c) level (P=0.007) after 3 months. A steady state was reached during the last 3 months. A multivariate logistic regression analysis was performed and identified factors predictive of improvement in HbA(1c) levels: HbA(1c) at baseline: odd ratio (OR)=1.749 (P<0.001), SMBG group (reference value: SMBG group): OR=0.665 (P=0.015), duration of diabetes: OR=0.953 (P=0.001) and BMI: OR=0.962 (P=0.039). This study is the first multicenter, controlled, prospective trial conducted on a large number of patients demonstrating that SMBG was statistically associated with a better quality of metabolic control than usual traditional recommendations alone in type 2 diabetes.

National Liberation, Neoliberalism, and Educational Change: The Case of Post-Apartheid South Africa

It is extremely informative to read recent World Bank reports concerning higher education in the so-called developing countries. (1) Although the prescriptions were firmly committed to promoting core neoliberal values, such as the curtailing of government spending and the reduction of unnecessary duplication of public educational services, a subtle turn of sorts has occurred: an equity agenda has been carefully interwoven into the Bank's more traditional recommendations to downsize the state, as well as to enhance competition, efficiency, and accountability in higher education through privatization. In Africa, this shift involving the notion of equity is in part an expression of the failure of socialist projects to rid nation-states of entrenched poverty and deep-seated class, religious, and racial-ethnic cleavages. The vacuum created by this failure to sustain radical economic programs in Africa has been filled by supranational or organizations that have seized the moment to articulate an equity agenda in higher education that is no longer viewed as anathema to a free market ideology. South Africa furnishes a good example of this kind of sea-change in perspective, insofar as in the volatile days of protest against the Nationalist Party regime prior to the fall of apartheid the Communist Party promised to nationalize banks and mines. This has given way to the African National Congress (ANC) government's endorsement of fiscally conservative macro-economic policies, such as the Growth, Employment, and Redistribution Strategy (GEAR). The equity agenda in the new South Africa must therefore contend with competing priorities that often compel the ANC government to construct a social justice platform with the sort of formulas for development that correspond to what the World Bank and other supranational organizations considered appropriate strategies for South Africa's economic survival and growth in the age of globalization. In this essay the governmental policies for transforming higher education in South Africa will serve as the primary landscape to explore the complex relationship between the country's national liberation struggle to overcome its racially divided history, and its post-apartheid future. It will examine the progressive reforms that contributed to the end of apartheid and the emergence of an equity agenda spearheaded by the ANC government. This case study of the University of the Western Cape (UWC) describes its radical transformation from a so-called bush college created by the apartheid state for the education of Coloured or mixed-race peoples to South Africa's first non-racial, ANC-aligned, open admissions institution. The historical lessons we can learn from UWC's transformation should inform the debate over the ANC government's recent decision to reduce the number of South African public higher education institutions. Influenced by the World Bank's neoliberal prescriptions for post-secondary institutions in developing countries, the restructuring of the South African higher educational system has centered on the neoliberal objectives of the global economy that emphasize the importance of fiscal restraint, standardization, efficiency, research productivity, and competition. (2) COLOUREDS AND ANTI-APARTHEID PROTEST IN THE WESTERN CAPE Until recently, the Coloureds were considered a somewhat obscure element in South African history. There are several reasons for their relative obscurity. The problematic designation Coloured has a distinctive meaning in the U.S. context; indeed, for many African Americans the term conjures up painful and humiliating memories of U.S. Jim Crow laws and the enforcement of separate and inferior public facilities in the southern states. Yet an examination of the experiences of the people designated as Coloureds in South Africa's province of the Western Cape furnishes critical insights into a number of political and economic conditions that are essential to understanding South African history. …

Vegetation Dynamics from Annually Burning Tallgrass Prairie in Different Seasons

Traditional perception of how tall grass prairie responds to fire at times other than late spring is either anecdotal or extrapolated from studies that lack spatial or temporal variability. Therefore, we evaluated patterns of change in vegetation cover, species richness, diversity, and aboveground biomass production on 2 different topographic positions from ungrazed watersheds that were burned annually for 8 years in either autumn (November), winter (February), or spring (April). Topoedaphic factors influenced the response patterns of some species to seasonal fire, although differences were primarily in the rate of change. Annual burning in autumn and winter produced similar trends through time for most species. Big bluestem (Andropogon gerardii Vitman) cover increased with all burn regimes, whereas indiangrass [Sorghastrum nutans (L.) Nash] increased only with spring burning. Repeated autumn and winter burning eventually increased perennial forb cover, with the largest increases occurring in heath aster [Symphyotrichum ericoides (L.) Nesom], aromatic aster [S. oblognifolium (Nutt.) Nesom], tall goldenrod (Solidago canadensis L.), and legumes. Species richness increased (P < 0.001) through time with spring and winter burning, but was similar among all burn treatments after 8 years of annual fire. Average grass and forb biomass did not differ among burn seasons on either topographic position, although interannual biomass production fluctuated inconsistently with time of burn. Our findings contrast with many of the conventional views of how tallgrass prairie vegetation responds to seasonal fire and challenges traditional recommendations that burning should only occur in late spring.

Vegetation dynamics from annually burning tallgrass prairie in different seasons

Traditional perception of how tallgrass prairie responds to fire at times other than late spring is either anecdotal or extrapolated from studies that lack spatial or temporal variability. Therefore, we evaluated patterns of change in vegetation cover, species richness, diversity, and aboveground biomass production on 2 different topographic positions from ungrazed watersheds that were burned annually for 8 years in either autumn (November), winter (February), or spring (April). Topoedaphic factors influenced the response patterns of some species to seasonal fire, although differences were primarily in the rate of change. Annual burning in autumn and winter produced similar trends through time for most species. Big bluestem (Andropogon gerardii Vitman) cover increased with all burn regimes, whereas indiangrass [Sorghastrum nutans (L.) Nash] increased only with spring burning. Repeated autumn and winter burning eventually increased perennial forb cover, with the largest increases occurring in heath aster [Symphyotrichum ericoides (L.) Nesom], aromatic aster [S. oblognifolium (Nutt.) Nesom], tall goldenrod (Solidago canadensis L.), and legumes. Species richness increased (P &lt; 0.001) through time with spring and winter burning, but was similar among all burn treatments after 8 years of annual fire. Average grass and forb biomass did not differ among burn seasons on either topographic position, although interannual biomass production fluctuated inconsistently with time of burn. Our findings contrast with many of the conventional views of how tallgrass prairie vegetation responds to seasonal fire and challenges traditional recommendations that burning should only occur in late spring.

Diabetes and hypertension: How low should you go and with which drugs?

Diabetes and hypertension are the most common causes of end-stage renal disease in the United States. Both experimental and clinical studies have demonstrated the importance of more intensive control of systolic blood pressure (SBP) in delaying progression of renal disease, particularly in diabetic patients with macroproteinuria. Although traditional recommendations have suggested that reducing systolic to <140 mm Hg is appropriate, there is consistent evidence in clinical trials demonstrating that, in the presence of diabetes, macroproteinuria, and impaired renal function, reducing systolic to <125 mm Hg will result in a more successful attenuation of the rate of progression of renal disease. In addition, there is convincing evidence demonstrating that blockade of the renin angiotensin system, particularly with angiotensin converting enzyme inhibitors, results in an improved opportunity to delay progression of renal disease. Despite the advantages of angiotensin converting enzyme inhibitors, most patients will require three to five medications to achieve optimal levels of goal SBP to attenuate the rate of progression of renal disease.

INTERACTIONS BETWEEN TEMPERATURE AND FERTILIZER CONCENTRATION AFFECT GROWTH OF SUBIRRIGATED PETUNIAS

To evaluate effects of fertilizer concentration and temperature on growth of petunia (Petunia × hybrida Hort. Vilm-Andr.), we grew petunias under three different day/night temperature regimes (35/27°C, 25/17°C, and 15/7°C) and with five different concentrations of fertilizers [electrical conductivity (EC) of 0.15, 1.0, 2.0, 3.0, and 4.0 dS m−1]. There was an interactive effect of temperature and fertilizer EC on the growth of the petunias. Optimal fertilizer EC decreased as temperature increased. Growth was better correlated with the EC of the growing medium than with the EC of the fertilizer solution. Irrespective of growing temperature, plant growth was best in treatments with a final growing medium EC of 3–4 dS m−1. The time to flowering was decreased, but flowers senesced more rapidly at higher temperature. Flower diameter decreased with increasing temperature. At the highest temperature (35/27°C), flower diameter also decreased with increasing EC of the fertilizer solution. The EC of the growing medium increased with increasing EC of the fertilizer solution and with increasing temperature. Effects on shoot nutrient concentrations were inconsistent among the three temperature treatments. At 25/17°C, a fertilizer EC of 2 dS m−1 resulted in the highest shoot N concentrations, while shoot N was not affected by fertilizer EC at 35/27°C or 15/7°C. Shoot P concentration increased with increasing fertilizer EC at a temperature of 15/7°C, but not at higher temperatures. These results indicate that fertilization guidelines for greenhouse growers should be based on maintaining the EC of the growing medium within an optimal range, instead of the more traditional recommendations based on the concentration of the fertilizer solution.

374 Interactions of Temperature and Fertilizer Concentration Affect Growth of Petunia and Geranium

Fertilizer recommendations for fertilizing bedding plants are normally based on nitrogen content of the fertilizer solution. However, nutrient availability is more closely related to the concentration of nutrients in the growing medium than the concentration in the fertilizer solution. Environmental conditions can affect the accumulation of nutrients in the growing medium and optimal fertilizer concentrations are likely to depend on environmental conditions. To test this hypothesis, we grew petunias and geraniums under three temperature regimes (35 °C/27C, 25 °C/17C, and 15 °C/7 °C) and with five concentrations of fertilizers [electrical conductivity (EC) of 0.15, 1, 2, 3, and 4 dS·m–1]. Temperature and fertilizer EC affected the plant growth. Optimal fertilizer EC decreased as temperature increased. Growth was better correlated with EC of the growing medium than with EC of the fertilizer solution. Irrespective of growing temperature, plant growth was best when EC of the growing medium was between 3 and 4 dS·m–1. A lower growing medium EC slowed down growth, presumably because of mild nutrient deficiencies. Higher fertilizer concentrations in the growing medium (&gt;4 dS·m–1) decreased growth because of salt stress. The EC of the growing medium increased with increasing EC of the fertilizer solution and with increasing temperature. Because of the interactive effect of fertilizer concentration and temperature on the EC of the growing medium, plants should be grown with more dilute fertilizer solutions at higher temperatures. Fertilization guidelines for growers should be based on maintaining the EC of the growing medium within an optimal range instead of the more traditional recommendations based on the concentration of the fertilizer solution.

Essential hypertension : part II: treatment.

The goal of antihypertensive treatment is to reduce overall CVD risk and thus its morbidity and mortality rates. In any given patient, the decision to begin treatment is governed by the risk of CVD, which is determined by the magnitude of the BP elevation and the presence or absence of target organ disease and/or additional CVD risk factors. Recent consensus committees, including JNC VI and the World Health Organization–International Society of Hypertension (WHO-ISH) Guidelines Subcommittee, have modified traditional treatment recommendations in several important ways3,35 : (1) Criteria for initiation of treatment now take into consideration total cardiovascular risk rather than BP alone, such that treatment is now recommended for persons whose BP is in the normal range but still bear a heavy burden of CVD risk factors or established CVD. (2) Systolic BP is recognized as an important target for treatment, particularly in older persons, because it is an even more important determinant of CVD risk than diastolic BP. (3) More aggressive BP goals are recommended for hypertensive patients with comorbid conditions such as diabetes mellitus or renal insufficiency. (4) The importance of tailoring the choice of antihypertensive drug treatment to the patient’s individual profile of concomitant CVD risk factors/comorbid conditions is emphasized. (5) The role of simultaneous reduction of multiple CVD risk factors in improving prognosis in hypertensive patients is stressed. (6) Home and ambulatory BP measurement has been recommended because of its value in guiding therapy and enhancing adherence to treatment. (7) Greater reliance on evidence-based medicine (ie, results of randomized controlled trials with CVD outcomes) in making treatment decisions has been endorsed. JNC VI has arrived at an empirical classification that stratifies hypertensive patients into risk groups for therapeutic decisions (Table 4⇓). Risk group A includes patients who do not have clinical CVD, target …

Optimal portfolio for nonstationary security market

A new interpretation of the classical portfolio problem is suggested. It is based on the optimization on the conditional expectation of a utility function where the conditional expectation is calculated taking into account all information available at the moment of decision making. This approach allows to show that the risk is a sequence of forecasting errors. Main classes of forecasting algorithms are described and compared. A similarity between some variants of solutions to the modified portfolio problem and the traditional technical analysis recommendations is shown. The scheme is essentially important for nonstationary nonequilibrium security market. Some results of its practical application to the Russian bond market are presented.

Article I: Prevention and education regarding rabies in human beings

Summary Substantial changes in the epizootic characteristics of rabies have transpired in the United States during the past 50 years. Traditional veterinary practices and public health recommendations have effectively controlled rabies in dogs and prevented associated human fatalities; however, they have been unable to adequately address the problem of rabies in wildlife. Attributable in part to a renewed focus on emerging infectious diseases, a conference was held at the Centers for Disease Control and Prevention in 1993 to begin discussion focused on the reemergence of rabies and to formulate new suggestions for prevention and control of rabies in the United States. Three major working groups were formed from a national committee of professionals representing a broad array of biomedical disciplines. These groups concentrated on prevention of rabies in human beings, education, laboratory diagnosis of rabies, and rabies control in animals. The groups described the perceived minimum requirements to promote prevention and control of rabies in the United States into the next century. The following article describes the needs and recommendations identified by the prevention and education working group. Two other articles, scheduled for the Nov 15 and Dec 1, 1999 issues of JAVMA, will relay the needs and recommendations of the working groups on laboratory diagnosis of rabies and rabies in wildlife.

Nonpharmacologic therapies that reduce blood pressure: a fresh perspective.

Traditional approaches to control the epidemic of blood pressure-related atherosclerotic cardiovascular disease (ASCVD) have largely focused on drug therapy in persons with hypertension. Still, nonpharmacologic therapy, also termed lifestyle modification, has an important and expanding role that complements drug therapy. Specifically, nonpharmacologic therapies can serve as initial therapy in Stage 1 hypertensive patients, facilitate medication step down or withdrawal in patients with well-controlled hypertension, prevent hypertension in high-risk populations, and reduce blood pressure in normotensive individuals and thereby lower their risk of ASCVD. Traditional lifestyle modifications that reduce blood pressure include sodium reduction, weight loss, moderation of alcohol intake, and increased physical activity. Such strategies have been prominently advocated in the Fifth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Recommendations to increase potassium, magnesium, and calcium intake were based primarily on general health considerations, not for control of high blood pressure. In its sixth and most recent report (JNC VI) published in 1997, the Joint National Committee has extended its recommendations. In addition to the traditional lifestyle recommendations, the JNC VI advocates increased potassium intake for control of high blood pressure. Furthermore, this policy-making body now recommends a healthy dietary pattern, that is, one that is rich in fruits, vegetables, and low-fat dairy products, and reduced in saturated fat, total fat, and cholesterol. This diet, which was rigorously evaluated in the Dietary Approaches to Stop Hypertension (DASH) clinical trial, substantially lowered blood pressure in normotensive and hypertensive individuals. These recent developments reinforce the hypothesis that multiple dietary factors influence blood pressure. Nonpharmacologic approaches have enormous potential as a means to reduce blood pressure and control hypertension, thereby preventing the occurrence of ASCVD. The current challenge to health care providers, government officials, and the general public is to develop and implement effective clinical and public health strategies that lead to desirable lifestyle modifications.

Advances in the treatment of hypertension.

Nonpharmacological Treatment of Hypertension The JNC VI paid much more attention than have previous JNC reports to nonpharmacological treatment of hypertension, particularly the Dietary Approaches to Stop Hypertension (DASH) diet. The traditional recommendations for controlling blood pressure by dietary means are to restrict salt and to lose weight. However, vegetarians generally have low blood pressure, and there is some evidence, albeit inconsistent, that dietary supplementation with potassium, calcium, and magnesium may also have beneficial effects on blood pressure. The DASH study showed that a combination diet rich in fruits and vegetables and in which saturated fat was replaced by low-fat dairy products produced a greater reduction of blood pressure than did the intervention in most other dietary studies. The DASH diet has high potassium, calcium, and magnesium content but is not low in sodium. One reason for this may have been that it was a “feeding” study rather than a “counseling” study—the subjects were provided with all their meals. Apart from its inclusion of low-fat dairy products, the DASH diet resembled the Mediterranean diet, which has gained support as the ideal diet for general health. What is particularly exciting about the DASH diet is that it may have benefits beyond lowering blood pressure. The health benefits of the Mediterranean diet have been tested in only 1 experimental human study, the Lyon Diet Heart Study, which found that deaths from both cardiovascular disease and cancer are reduced in subjects consuming the Mediterranean diet. Further indirect evidence for benefits from the DASH diet beyond blood pressure reduction comes from a prospective study of the relationships between the dietary intake of minerals and stroke performed in 43 738 men who were participants in the Health Professionals Follow-up Study. The intake of potassium, magnesium, and fiber (but not of sodium or calcium) was inversely associated with the risk of stroke during an 8-year follow-up period. The DASH diet had the same amount of potassium, magnesium, and fiber as the highest quintiles of intake reported in the Health Professionals Study. Another important study of the nonpharmacological treatment of hypertension was the Trial of Nonpharmacologic Interventions in the Elderly (TONE). Most of the trials of the effects of salt restriction and weight loss on blood pressure have been conducted in middle-aged people, although there is evidence that older people may be salt sensitive. TONE showed that modest salt restriction and weight loss enables a substantial number of elderly hypertensive patients to discontinue antihypertensive medication.

Rational prescribing of extended-spectrum penicillin beta-lactamase inhibitor combinations: focus on ticarcillin/clavulanic acid.

To provide an overview of the clinical pharmacokinetics and pharmacodynamics of ticarcillin/clavulanic acid and to reassess traditional dosage recommendations based on contemporary pharmacokinetic and pharmacodynamic principles. Published ticarcillin and clavulanic acid pharmacokinetic data derived from infants and children combined with data obtained from a rigorous, dose-escalation study performed in 12 healthy adults. Pharmacodynamic correlates were derived from published in vitro susceptibility data for the combination drug ticarcillin/clavulanic acid. Limited differences were observed in the pharmacokinetic disposition profiles between ticarcillin and clavulanic acid and relative to subject age. Integration of these data with defined pathogen minimum inhibitory concentrations underscores the appropriateness of an extended dosing interval (e.g., q8h to q12h) for many infections and demonstrates the probable therapeutic interchangeability of the following three intravenous dosing regimens: 3.1 g every 6 hours, 75 mg/kg every 8 hours, and 100 mg/kg every 12 hours of a 30:1 ticarcillin/clavulanic acid combination. Integration of pharmacokinetic and pharmacodynamic data is an appropriate means to assess/reassess dosing recommendations for antimicrobial agents. Initial ticarcillin/clavulanic acid dose recommendations did not account for known dynamic interactions for this combination antibiotic. Pharmacokinetic data in infants, children, and adults support a less frequent dosing interval (q8h to q12h) for the treatment of infections arising outside the central nervous system.

Radiotherapeutic management of bulky cervical lymphadenopathy in squamous cell carcinoma of the head and neck:Is Postradiotherapy Neck Dissection Necessary?

Although traditional recommendations for the management of bulky cervical lymphadenopathy (AJCC categories N2-3) with definitive radiotherapy call for postradiotherapy neck dissection regardless of treatment response, recent data suggests that this policy can be modified on the basis of tumor regression rate. In a series of 130 patients with stage III-IV squamous cell carcinoma of the head and neck managed with a concomitant boost-accelerated hyperfractionated radiotherapy schedule, 81 cases had cervical lymphadenopathy at the time of referral. Patients were analyzed with respect to regional control outcomes for those having complete and incomplete clinical responses during the initial 3-month follow-up interval. The general management policy has been close observation of patients demonstrating complete clinical responses to radiation rather than postradiotherapy neck dissection. Failure patterns were examined in the 58 patients classified as complete responders. Failure occurred in the primary site in 16 (28%) of these patients, while isolated neck failure occurred in only 3 (5%). Neck recurrence rates for patients with maximum lymph node size < or = 3 cm vs. > 3 cm were not statistically different at 3-year follow-up (94% vs. 86%). Among the 23 incomplete clinical responders, 18 had incomplete neck responses. Five of these patients underwent salvage neck dissection; 4 remain clinically free of recurrence. The remaining 13 patients who either refused or were not eligible for salvage surgery ultimately succumbed with persistent loco-regional disease. The policy of observation after complete response to the radiotherapy schedule employed here was associated with a very low incidence of isolated neck failures and was safe and appropriate in patients who can be followed reliably. The prognosis for patients who failed to respond in the neck was poor except for those who underwent salvage surgery.

Cost analysis and clinical impact of weekly ventilator circuit changes in patients in intensive care unit

Background: The introduction of heated circuits and sealed, single-use humidifiers has prompted some investigators to question the traditional recommendations for changing vertilator circuits. We studied the clinical and cost impact of extending the circuit change interval from 72 hours to 7 days in our two intensive care units with 17 beds. Methods: With standard surveillance definitions from the Centers for Disease Control and Prevention and the National Nosocomial Infections Surveillance System, baseline pneumonia rates were established for a 3-month period. After the institution of weekly circuit changes, daily surveillance of intubated patients was performed during 18 of 22 weeks from May through September 1993. Standard microbiologic methods were used for the identification of patient and environmental isolates. Results: Ventilator-associated pneumonia for the 72-hour circuit change group was 9.1% or 1.29 per 100 ventilator days. After the institution of weekly changes, pneumonia occurred in 9 of 146 patients (6.2% or 0.74 per 100 ventilator days χ 2= 0.33, p = 0.44). No common bacterial isolates were recovered as judged by phenotype, biochemical, or antimicrobial susceptibility patterns. Weekly changes reduced the number of circuits used from a predicted 469 to 214. Estimating $26.46 per circuit change, annualized cost savings were $20,246.90. Conclusions: Weekly circuited changes in patients undergoing ventilation therapy in the intensive care unit are cost-effective and do not contribute to increased rates of nosocomial pneumonia.

How much physical activity should we do? The case for moderate amounts and intensities of physical activity.

A sedentary and unfit way of life leads to increased risk for several chronic diseases and premature mortality. Sedentary and unfit individuals are also more likely to develop functional limitations as they age. The precise type, amount, and intensity of physical activity required for protection needs further investigation. Traditional exercise recommendations suggest a threshold of activity that is necessary for protection, although current evidence does not support a dichotomous view of this issue. Clinical and epidemiological studies show a continuous dose-response gradient of outcome variables across a wide range of activity or fitness levels. Moderate amounts and intensities of physical activity are associated with improved health and reduced risk of morbidity and mortality when compared with low activity or fitness. The major public health emphasis for physical activity recommendations and programming should be to encourage the most sedentary and unfit 20 to 25% of the population to become at least moderately active, and this can yield substantial benefits for the population.

Effectiveness of the non-spermicidal fit-free diaphragm

Standard instructions for diaphragm use call for an individually sized latex diaphragm, used in conjunction with spermicide jelly. However, some investigators have reported that the diaphragm can be effective without a spermicide. A non-randomized trial designed to measure the contraceptive effectiveness of the diaphragm used without spermicide was conducted. A total of 110 self-selected women were enrolled to use a non-spermicide fit-free (60mm) diaphragm for a period of one year. They were advised to wear the diaphragm continuously, removing it once each day for washing but not within six hours after intercourse. Product-related problems related to insertion, retention and removal were few at both the 6- and 12-month follow-up visits, most commonly odor. The 12-month life table accidental pregnancy rate during typical use was 24.1 per 100 women (29.5 per 100 women without female barrier experience and 17.9 per 100 women with barrier experience). Over 85% of the women who returned for follow-up visits reported using the diaphragm during every act of intercourse. Until better data refute the traditional recommendations, users should be advised to add spermicide to fitted latex diaphragms.

New recommendations for building in tropical climates

Traditional recommendations for building a thermally efficient or comfortable building in a tropical climate are briefly summarized. They suffer from three main drawbacks: they are not quantitative, partly incorrect and only for two climates: the hot dry and the warm humid. A new climate classification, made up of forty tropical climates is presented. Eight building elements, which affect the thermal system of a building, are distinguished. The method by which the new recommendations are derived, is discussed. The new recommendations are briefly presented. A complete overview of all recommendations is in a report, obtainable from the author.

Desirable standards for laboratory tests if they are to fulfill medical needs

Many strategies to define desirable standards for laboratory tests to fulfill medical needs have been proposed over the last three decades. Traditional approaches are based on reference (normal) values, opinions of clinicians, the state of the art, views of experts, data on biological variation, and assessment of the effect of error on clinical use. All these approaches have advantages and disadvantages, but the consensus of experts reached over a decade ago that imprecision desirably be less than one-half of the within-subject biological variation still seems to provide the best set of generally applicable performance standards. Desirable bias is less than one-quarter of the group (within-subject plus between-subject) biological variation. Recent proposals are either restatements of traditional recommendations, further empirical suggestions, or models based on assessment of clinical needs, and have not been widely accepted. Both old and new studies on clinical opinions, sought by using structured questionnaires containing clinical vignettes designed to seek views on the magnitude of significant change, are flawed in design, execution, and data analysis. Until clinicians are more aware of test-result variability and clinical chemists gain quantitative knowledge on the interpretation of test results, it will be difficult to set desirable standards that fulfill actual medical needs, except in a few well-defined screening situations.