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Condom availability for adolescents.

Although abstinence should be stressed as the certain way to prevent STDs and pregnancy, sexually active teens, male and female, must nonetheless be taught to use condoms properly, effectively, and consistently. The latex condom should be made widely available to young people. Ideally, young persons should have access to education and counseling when contraception is dispensed. However, condoms should be made easily available without any requirement for education. Condoms should be available not only through families, medical facilities, and commercial channels, but also through other appropriate and informed persons, without cost if possible, at sites where adolescents congregate. These sites may include schools, clubs, and other youth-serving agencies. A clear message from the medical community supporting condom use will enhance compliance.

Adolescent↗

[Changes in lipid availability in Venezuela, 1970-1992].

The authors carry out a research focused on the quantification and analysis of the main changes in feeding and nutrition in Venezuela between 1970 and 1992. Such research started with the review and adjustment of the Food Balance Sheets (Hojas de Balance de Alimentos) elaborated by the Instituto Nacional de Nutrición (National Nutrition Institute) between 1970 and 1979 in order to homogenize them in a methodological way to make them similar to those elaborated by that institution and the Fundación Polar for the 1980-90 period. Estimates were made about the daily and per person availability of food for human consumption (DCH) for 1991 and 1992. This report, a partial product of that research, characterizes the evolution of the lipidic DCH in Venezuela for the 1970-1992 period. This period has been divided in seven stages of the evolution of the total energetic DCH, as this reflects well the course of the daily and per person Food Purchasing Power (PCA); there is a direct and strong functional relationship between these two variables. Along those stages the behaviour of the lipidic DCH is studied and we try to view possible relationships between the evolution of the Venezeluans economical situation and the absolute and relative variations observed in the level and the structure of the lipidic DCH. This structure is analyzed from several points of view: groups of food sources, origin, "visibility", and place of origin. One purpose is to determine also which food groups are mainly responsible for the venezuelan's external lipidic dependence. A general picture of the evolution of the DCH for saturated fatty acids and cholesterol is made, as well as of the variations experienced by the P/S and M/S relationships. It was found that the most dynamic elements, those that can explain a very high percentage of the variations observed in the level and the structure of the lipidic DCH were: the groups of foods of Visible Fats, Milk and dairy products, and Meats; vegetal lipids; vegetal-visible and animal-invisible lipidic fractions; imported lipids or lipids of food products which raw materials were imported (oily raw materials to make oils and edible solid fats, and raw materials to make food for poultry and hogs). The importance of the food groups Visible Fats, Milk and dairy products, and Meats, as sources or saturated fatty acids in the diet of the Venezuelans was made evident (89-91% of the respective total DCH), as well as the importance of the food groups Eggs, Meats, Fish and Seafood, and Milk and dairy products, as sources of cholesterol (82-89% of the available total). It was found that the lipid-originated calories account for less than 30% of the total energetic DCH; saturated fatty acids account for less than 10% of the available calories/person/day; the DCH for cholesterol did not reach the level of 300 mg/p/d; the P/S and M/S relationships remained close to 1. These last four facts are considered favorable for the health of the human being.

Cholesterol, Dietary↗

Professional perceptions of availability and quality of mental health services in Wisconsin.

Eighty-six county coordinators and psychiatrists from predominantly rural counties reported their perceptions of availability and quality of 21 types of inpatient, outpatient, and transitional living services in Wisconsin for five target populations: adult, children, adolescent, geriatric, and minority. Their ratings and priorities for addressing needs indicated (a) that transitional living services are insufficient and of inadequate quality for all populations; (b) that availability and quality of inpatient and outpatient services are better for adults; (c) that general needs across all populations for additional and higher quality services are for services that address specialized problems, both inpatient and outpatient; (d) that children, adolescent, minority, and geriatric populations have limited access to needed services; (e) that available services for these four groups are most often inadequate; and (f) that the needs of children and adolescents should be given highest priority, particularly their needs for transitional services and inpatient and outpatient services for special problems. Actions and recommendations are discussed for professionals and advocates to increase awareness of needs for quality services for children and adolescents, for expanding public information, and for design of local-county quality programs, including professional education and continuing outreach to important constituencies and advocates.

Adolescent↗

A randomised intervention study to examine the effect on immunisation coverage of making influenza vaccine available at no cost.

AIMS: This study aims to assess the effects of two interventions on influenza vaccination coverage: a simple organisational strategy, and making the vaccine available free. METHODS: Sixteen general practitioners in the Auckland region were randomly selected to participate. Patients over 65 years of these general practitioners were randomly allocated to control, letter of invitation for a flu vaccine, or offer of a free flu vaccine. Administration of a flu vaccine for each person in the study was documented in each general practitioner surgery. Vaccine coverage for each of the three groups was measured. RESULTS: Results were available for 15 of the 16 participating general practitioners, a total of 2791 subjects. Immunisation coverage rates for control, letter of invitation and vaccine at no cost, were 17%, 27% and 45% respectively. Statistical analysis, allowing for the cluster method used to obtain subjects, showed risk ratios of 1.55 and 2.65 for the two interventions, with p values of < 0.00001. CONCLUSIONS: A potential source of bias in this study is underreporting of administration of vaccine to people in group 1. Notwithstanding this potential bias, both interventions were highly effective at increasing the uptake of influenza vaccine in the elderly population. General practitioners should be recommended to routinely invite patients over 65 years to have a flu vaccine. Given the commitment of the Ministry of Health to the vaccination against influenza of people over 65, this study would suggest that serious consideration should be given to making the vaccine available at no cost to this age group.

Aged↗

How important is publication bias? A synthesis of available data.

It has long been recognized that investigators frequently fail to report their research findings (Dickersin, 1990). Chalmers (1990) has suggested that this failure represents scientific misconduct since volunteers who consent to participate in research, and agencies that provide funding support for investigations, do so with the understanding that the work will make a contribution to knowledge. Clearly, knowledge that is not disseminated is not making a "contribution". This failure to publish is not only inappropriate scientific conduct, it also influences the information available for interpretation by the scientific community. Of course, if research is left randomly unpublished, there is less information available, but that information is unbiased. We now have solid evidence that failure to publish is not a random event; rather, publication is dramatically influenced by the direction and strength of research findings (Dickersin et al., 1987, 1992; Dickersin & Min, 1993; Easterbrook et al., 1991; Simes, 1986). This tendency of editors and reviewers to accept manuscripts submitted by investigators based on the strength and direction of the research findings is termed "publication bias". The problem has been under discussion for many years and has recently been studied directly in medicine and public health. This article will review the major evidence available regarding publication bias and will suggest measures for overcoming the problem.

Clinical Trials as Topic↗

Androgenic regulation of NO availability in rat penile erection.

Prior studies from this laboratory, using untreated castrated (CASTRATE) rats and testosterone-treated castrated (TESTO) rats, have shown that the magnitude of the intracavernosal pressure increase during erection is androgen dependent. Studies from this and other laboratories have also presented evidence suggesting that penile erection is mediated principally by nitric oxide (NO). The present report was designed to confirm that androgens maintain the availability of cavernosal NO and to determine if this androgenic action is exerted at the genomic level modulating the expression of the neuronal form of the nitric oxide synthase gene (nNOS). The results showed that administration of supplemental L-arginine failed to augment the erectile response in either group, suggesting that substrate availability is not a cause of the reduced response in CASTRATE animals. Inhibition of NO synthesis with a nitro-arginine competitive inhibitor of nitric oxide synthase enzyme protein (NOS) resulted in strong inhibition of erection in both TESTO and CASTRATE rats. When given in conjunction with ganglionic stimulation to induce erection, the NO releasing drug, sodium nitro-prusside (SNP), increased intracavernosal pressure in CASTRATE rats but not in TESTO rats, suggesting a deficiency of the available NO in CASTRATE-animals. Finally, reverse transcription-polymerase chain reaction (RT-PCR) demonstrated that mRNA levels for the enzyme nNOS in the penis were greater in TESTO animals than in CASTRATE rats. These results support the hypothesis that androgens mediate the erectile response in the rat penis by stimulating the expression of the neuronal isoform of nitric oxide synthase, thus maintaining an adequate supply of NO.

Analysis of Variance↗

Information systems tools available to the case manager.

Regardless of the setting, the role of the nurse as a manager of care continues to grow and develop. The nurse case manager needs to have vital information readily available to facilitate critical thinking, analysis, and decision-making on the appropriateness of care provided to patients and to ensure that optimal outcomes are achieved. While there are a variety of clinical information systems available, it is evident that the complexity of the case manager's information needs presents challenges for software developers. Accordingly, nurse case managers must take an active role in defining and communicating their needs. The purpose of this article (the first of two) is to present a general overview of the information needs of the nurse case manager and the computerized information system tools available (and emerging) to meet these needs. A follow-up article in the next issue of Nursing Case Management will focus on a typical clinical information system selection process; outline specific ways the nurse case manager can effectively influence that process; and provide a checklist that will enable the nurse case manager to assist the institution in selecting and implementing the most appropriate system.

Case Management↗

Human cells and cell cultures: availability, authentication and future prospects.

The availability of well characterized, viable human cells, tissues and cell lines along with pertinent data on the specific patient donors is a prerequisite for much current transplantation and biomedical research. In the USA, institutional and multi-center networks have been established for provision of primary human cells and tissues to qualified clinicians and research scientists. Monetary support derives from government, university, institutional and fee sources. Problems involved include concern for the rights and privacy of tissue donors, cultural reservations relating to tissue provision, the need for safe and expeditious transport, short term survival and limited supply, adequate correlation of patient data with samples provided, presence of infectious viruses and microorganisms, as well as state or government regulations regarding national or international shipping. The use of human cell lines with continuous or even somewhat limited doubling potentials overcomes many of the above difficulties. National cell banks have been established to provide reference lines for use by multiple investigators. Use of such cell lines assures improved research comparability both geographically and with time. Authentication procedures are critically important for all of these programs. Verification of tissue types and conditions is required through histological, biochemical and immunological assays. Tests for microbial and viral contaminants must be applied. In addition to such procedures utilized for tissues, with cell lines the banking agency must also verify species and where possible identity, properties and functions. The literature is replete with descriptions documenting incorrect identifications and infections of proliferating cell strains used for research. The availability of viable tissue through local sources and distribution agencies in the USA is becoming more commonplace even including full family participation and collection of related, detailed histories. Increased support for this developmental activity is needed, coupled with provision of blood and normal cells and cell lines from family members in many disease categories. Modern techniques, new and improved culture ware, serum-free media, reagents such as growth, adherence and transfer factors will permit isolation, propagation and wide spread distribution not only of human tumor cells but also normal and functional human cells of most renewing and expanding tissue types. Hybridization and immortalization techniques are enhancing this capability such that virtually all human cell types should be available for short or longer-term propagation and study in the foreseeable future.

Biological Specimen Banks↗

Stimulation-dependent redistribution of charge movement between unavailable and available states.

A previous study (Stroffekova and Heiny 1997) demonstrated that changes in resting, intracellular free Ca2+ can modulate the amount of charge which is available to move upon depolarization and do excitation-contraction-coupling (E-C coupling). Charge movement reflects voltage-driven conformational changes of the dihydropyridine receptor which couple membrane excitation to Ca2+ release from the sarcoplasmic reticulum (SR) and contractile activation (c.f. review: Melzer et al. 1995). The present study demonstrates that dynamic changes in free Ca2+ that occur in the triadic gap during SR Ca2+ release can likewise produce a stimulation-dependent increase in the amount of available charge. Thus this modulation occurs in the physiological range of Ca2+ changes that occur in the triad during normal muscle activity. The modulation of charge movement by intracellular Ca2+ was rapid and maintained; it occurred within 2-3 suprathreshold depolarizations and remained for 5-10 minutes. It could be prevented by intracellular BAPTA and by depleting the SR of Ca2+, but not by EGTA or agents known to alter ion channel phosphorylation. These results are explained by a model in which a Ca2+ binding site on or near the voltage-sensor is normally populated by Ca2+ ions released into the triadic junction during activity and modulates the distribution of voltage sensors between available and unavailable states.

Animals↗

Which primary total knee replacement? A review of currently available TKR in the United Kingdom.

Comparative information on total knee replacements (TKRs) is not readily available. With the help of implant manufacturers and distributors, we have compiled a list of TKRs on the market in the UK and summarised the information about these implants in a table. There are 37 different TKRs, marketed by 14 companies; 54% have been introduced since 1990. The number of different implants is increasing. At least eight designs have undergone major modifications, while many have had minor alterations. Of the TKRs on the market, 60% are modular. Some 54% of TKRs have no published results in peer-reviewed journals; only one of the four most widely used prostheses has published survival figures. New and modified implants are introduced without clinical evidence of their superiority over other available designs. Published results in peer-reviewed journals are currently the best evidence available on the reliability of an implant. When selecting an implant, surgeons should be aware if the prosthesis has any such results, the length of the follow-up, and the survival rates that are achieved. More detailed interpretation is difficult because of the different combinations used in modular implants and because of the frequent modification of existing designs. Properly conducted long-term clinical trials should be encouraged as they are the only means of evaluating new designs.

Costs and Cost Analysis↗

Trends in general practice in the Waikato, 1979-80/1991-92, I: Practitioner availability, service use and clinical activity.

AIMS: To document trends in availability and use of general practitioner services and in patterns of clinical activity for the Waikato over the period 1979-80 to 1991-92. METHODS: The data are drawn from a baseline and a follow-up survey of general practice in the Waikato region representing a 1% sample of all in-surgery, in-hours, week-day encounters at two points in time. The data were recorded by participating general practitioners in four collection weeks spaced over the period of a year. In total, 9468 and 10,235 patient encounter forms were completed. RESULTS: While the number of general practitioners increased by a half over the period, average workload declined by a fifth, the inflation-adjusted value of the usual adult fee increased by nearly 50% and visits went up by an average of a half a visit a year. Clinical activity declined for prescribing but increased for referral and follow-up. CONCLUSIONS: The increase in availability of general practitioners over the last decade has been associated with significant changes in patterns of practice organisation, service utilisation and clinical activity. Further research is required into the potential impact of greater service availability on patient demand and resource use.

Adult↗

Zolpidem self-injection with concurrent physical dependence under conditions of long-term continuous availability in baboons.

Intravenous zolpidem self-injection, and the concurrent development of physical dependence under conditions of continuous drug availability, was characterized in three baboons. Previously, under similar conditions, 1.0 mg/kg midazolam maintained low, but stable, daily rates of self-injection (e.g. less than 20 injections/day) over 30 or more days and resulted in the development of physical dependence in baboons. In the current experiments, saline and zolpidem (1.0 mg/kg) were available for self-injection under a fixed-ratio (FR-30) schedule of lever-pull responses with a 5 min time-out after each injection. Saline maintained only low levels of responding (i.e. less than five injections per day). Zolpidem maintained an orderly spaced within-day pattern of injections and daily rates of self-injection were higher than saline (i.e. 10 or more injections per day). Daily rates of zolpidem self-injection were relatively stable in two baboons, and increased over time in the third baboon. Substitution of saline for zolpidem produced a rapid decrease in responding that remained low (i.e. less than five injections per day) in all three baboons. Chronic self-injection of zolpidem produced an increase in responding maintained by food pellet delivery and an increase in body weights. Administration of flumazenil (0.1-1.0 mg/kg, i.v.) after at least 35 days of zolpidem self-injection produced postures and behavioral signs typical of a classic flumazenil-precipitated benzodiazepine withdrawal syndrome. Substitution of saline after chronic zolpidem self-injection produced a time-limited spontaneous withdrawal syndrome. Behavioral signs and postures were similar to those observed during flumazenil-precipitated withdrawal and were most prominent during the first 8 days after zolpidem was discontinued. Therefore, like midazolam, zolpidem maintained self-injection and physical dependence developed under conditions of long-term continuous availability.

Animals↗

Comparative investigations into the content of available molybdenum in important soils of the arid and humid tropics.

The determination of the content of available molybdenum in 196 soil samples from different geographical (Yemen, Sudan, Tanzania, Ghana, Cuba, and Sri Lanka) and climatic (annual precipitation 30-3000 mm) regions gave these results: 1. Arid and subarid soils of dry regions as well as rendzina-type soils contained the highest amount of available molybdenum (0.216 ppm respectively). The lowest content was determined in the ferrallitic soils of the humid tropics (0.045 ppm). These differences are mainly attributed to high pH values and CaCO3 content in aridisols and rendzina-type soils and to a strongly acid soil reaction in ferrallitic soils. 2. The content of available molybdenum was significantly positively correlated with the pH, percentage base saturation, CEC and exchangeable Ca; it was negatively correlated with the clay content. 3. Deficiency of molybdenum is hardly to be expected in arid and subarid soils (24 per cent of all samples deficient). The proportion of samples with a low Mo content and the probability of Mo deficiency increases in this order: vertisols (40%) leads to fersiallitic soils (64%) leads to ferallitic soils (89%).

Cuba↗

Systemic availability of orally administered meperidine.

A comparison of the areas under the plasma concentration-time curves after intravenous and oral administration of meperidine in 4 normal subjects indicated that 48% to 56% of the oral dose avoided "first-pass" metabolism and was systemically available. Similar estimates were obtained by applying the Loo-Riegelman method for calculating drug absorption viz, 47% to 60%. Oral availability predicted from a knowledge of drug clearance (blood) after intravenouration-time curves after oral administration exhibited irregularities and double peaks possibly indicative of the action of meperidine on the gut or a recycling process.

Administration, Oral↗

In vitro availability of minerals of some tropical and citrus fruits as influenced by antinutritional factors.

Four tropical fruits and three citrus fruits were analyzed for moisture, ash, antinutritional factors (phytate, oxalate, and polyphenols) contents, and total and available minerals. Moisture contents ranged from 6.0 to 83.17% for tropical fruits while that of citrus fruits ranged from 88.20 to 89.50%. Ash contents ranged from 2.56 to 4.50% and from 3.83 to 4.83%, for tropical and citrus fruits, respectively. All fruits contained no oxalate while phytate and polyphenols ranged from 48.1 to 134.1 mg/ 100 g and from 0.115 to 0.34%, respectively. For all fruits major minerals contents ranged from 7.7 to 433.3 while trace ones ranged from 0.116 to 1.91 mg/100 g. In vitro availabilities of major minerals (% of total) varied from 11.1 to 86.2% while for minor ones it ranged from 13 to 72.5%.

Biological Availability↗

Interspecies differences in systemic drug availability following subcutaneous pulsatile administration in cattle, sheep, dogs, and rats.

Rats, dogs, sheep, and cattle were implanted subcutaneously with stainless-steel tissue cages. Bolus injections of cefoxitin and ivermectin were administered to the interiors of the tissue cages 11, 32, and 60 days after implantation to simulate pulsatile drug release from an implanted device. Plasma drug levels were determined for 6 h for cefoxitin and up to 8 days for ivermectin. Tissue cages were retrieved 3 and 6 months after implantation for macroscopic and microscopic examination. In dogs and rats, plasma levels of both drugs following administrations to the tissue cages were significantly lower than those following subcutaneous injection, suggesting that the tissue growth around and in the cages posed a barrier to systemic drug availability in those species. In cattle and sheep, the tissue cages and associated tissue did not inhibit systemic availability of either drug as compared with routine subcutaneous administration.

Animals↗

Comparative pharmacokinetics of coumarin anticoagulants. XLII: Effect of phenobarbital on systemic availability of orally administered dicumarol in rats with ligated bile ducts.

The purpose of this investigation was to determine if the previously demonstrated inhibitory effect of phenobarbital treatment on the systemic availability of orally administered dicumarol in rats is related to the known effect of phenobarbital on bile output. It was found that phenobarbital had no apparent effect on the systemic availability of an aqueous dicumarol suspension in rats with ligated bile ducts. Compared to results obtained previously on normal rats, bile duct-ligated rats absorbed and eliminated dicumarol much more slowly and absorbed much less of the anticoagulant. On the other hand, the relative inductive effect of phenobarbital treatment on dicumarol elimination was similar in normal and in bile duct-ligated animals. The latter exhibited substantial serum transaminase elevations, indicative of liver damage presumably secondary to cholestasis. These results demonstrate that a drug-drug interaction can depend markedly on the pathophysiological status of the animals.

Animals↗

Determination of bioavailability and systemically available fractions of drugs undergoing reversible metabolism: application to 4-amino-5-chloro-2-[2-(methylsulfinyl)ethoxy]-N-[2- (diethylamino)ethyl]benzamide and its sulfide and sulfone metabolites in rats.

Methods are discussed which permit the calculation of the bioavailability (F) and fraction of an oral dose entering the central circulation (f) of a drug and its interconversion metabolite. The interrelationships between the F and f and between the F and systemically available fractions afforded by reversible metabolism are also derived and described. The application of these principles is illustrated by the pharmacokinetic analysis of 4-amino-5-chloro-2-[2-(methylsulfinyl)ethoxy]-N-[2- (diethylamino)ethyl]benzamide (ML-1035, 1) and its sulfide (2) and sulfone (3) metabolites in rats. Like intravenous ML-1035, ML-1035 administered orally underwent metabolic interconversion with 2 but not with 3 in this species. Both ML-1035 and 2 were absorbed rapidly and are pharmacologically active. On average, 8.3 and 13% of an oral dose (152.4 mumol/kg) of ML-1035 were bioavailable as ML-1035 and its sulfide metabolite, respectively, while 23 and 65% of a molar equivalent dose of the sulfide metabolite were bioavailable as either compound, respectively. Thus, the sulfide metabolite is better absorbed than ML-1035 in rats. Following oral administration of either ML-1035 or 2, the systemically available fractions of both compounds were weakly to moderately influenced by the reversible metabolism process in rats. Moreover, the bioavailability of the sulfone metabolite was very poor (2.5-4%) following separate oral administration of ML-1035, 2, and 3.

Animals↗