SEARCH · PubMed Health

Results for “availability”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25Linked to original sources

PubMedDate not supplied

The availability of tetracyclines in calves.

The bioavailability of oxytetracycline (OTC) and chlortetracycline (CTC) was studied in non-fasting calves. The availability of OTC was found to be 5% and of CTC 37% after oral administration of 10 mg/kg. The availability was reduced when the drugs were given in a milk replacer or in cow's milk. The area under curve (AUC) was reduced 68% when OTC was given in milk replacer, the reduction of CTC availability was 40%. In milk the reduction was 72% for OTC and 47% for CTC. Calcium and iron caused a dramatic reduction of the serum levels. OTC was stored mixed in milk powder at room temperature for 6 months without loss in availability. OTC did not chelate calcium ions in serum. The conclusion drawn from the results was that CTC is more suitable than OTC for oral therapy in calves.

Administration, Oral↗

PubMed1994

Application of NONMEM method for evaluation of relative biological availability of ofloxacin.

The nonlinear mixed effect model (NONMEM) method for analysis of population pharmacokinetics, was applied to evaluate the relative biological availability of 2 ofloxacin (Ofl) products. The data of randomized crossover study of 2 kinds of Ofl tablets in 12 healthy volunteers were analyzed by NONMEM, as well as standard approach. The relative biological availability evaluated by NONMEM (F = 97.3 +/- 5.0%) was close to that by standard approach (F = 98.2 +/- 3.6%). NONMEM was also valid in accurately evaluating the relative biological availability using sparse clinical data (F = 91.7 +/- 8.0%) which could not be analyzed by standard approach. Thus, the usefulness and advantages of NONMEM were ascertained for the evaluation of biological availability using observational or experimental data.

Adult↗

PubMed1977

The bio-availability of beta-acetyldigoxine (Novodigal) alone and combined with oxyfedrine (Ildamen-Novodigal).

The bio-availability of various galenic preparations of beta-acetyldigoxine was tested in six healthy probands after a single oral dose (1 mg). The availability parameters were calculated from the areas under the plasma concentration curves and from the cumulative urinal excretion. There was no significant difference between the bio-availabilities of Novodigal (beta-acetyledigoxine tablets), Ildamen-Novodigal (beta-acetyldigoxine and oxyfedrine) and an alcoholic solution of beta-acetyldigoxine. Correlation calculations showed that the determination of the plasma concentration courses up to six hours after substance application are most favourite in regard to judging the absorption processes of digoxine preparations. For the assessment of the bio-availability, the methods of comparing the areas under the blood level curves of 0 to 6 hrs and of comparing the cumulative urinal excretion over a period of 24 hrs were of equal validity.

Adult↗

PubMed1991

Slide presentation graphics using a personal computer. A comparative evaluation of available software.

Most of the available methods for preparing professional slides to be used in oral presentations can be cumbersome, time-consuming, and expensive. Creating high-quality 35-mm slides may require the use of expensive medical illustrators and photographic equipment not available to all physicians. More recently, technology has emerged that permits professional in-office generation of quality slides using commercially available computer graphics software and film recorders. Such a system is simple to establish and maintain when compared with commercial slide production facilities. We will review the hardware requirements of such a system, as well as the advantages and disadvantages of several commercially available software packages. Using a personal computer-based slide-making system, any physician communicating with small or large groups of people can now produce professional-looking slides easily, rapidly, and inexpensively.

Audiovisual Aids↗

PubMed1987

Patterns of calling time and ipecac availability among poison center callers.

Over a one-month period all telephone calls from the public (n = 3828) to a regional poison center were analyzed. The proportion of early calls (within ten minutes of exposure) decreased with age. Late calls (greater than 30 minutes) were significantly associated with higher hospital referral rates when compared with earlier calls in children younger than 5 years (4.6% vs 1.8%) and adults (33% vs 15%). Ipecac was available in 59% of the homes of callers with children younger than 5 years. Hospital referrals were significantly less common among children who had ipecac at home (1%) compared with children who did not (3%). While the availability of ipecac was similar among callers and a matched sample of households who previously called the poison center (58%), ipecac was much less frequently available (24%) among households whose members had not previously called the center. These data infer that educating the public to call the poison center promptly may result in reduction of hospital referrals. Poison education efforts should be targeted to populations with low ipecac availability and low utilization of the poison center.

Adolescent↗

PubMed1995

Seasonal variation in plasma L-tryptophan availability in healthy volunteers. Relationships to violent suicide occurrence.

OBJECTIVE: To investigate the seasonal variation in levels of plasma L-tryptophan and competing amino acids (CAAs) in healthy humans in relation to climatic variables, total serum protein levels, and violent suicide occurrence. METHODS: Twenty-six healthy volunteers (13 men and 13 women; mean [+/- SD] age, 38.7 +/- 13.4 years) had monthly blood samplings for assays of L-tryptophan, valine, leucine, isoleucine, tyrosine, and phenylalanine during 1 calendar year. RESULTS: Significant annual rhythms were detected in L-tryptophan, the L-tryptophan/CAA ratio, phenylalanine, valine, and leucine, and semiannual rhythms in L-tryptophan values and in L-tryptophan/CAA ratios. Plasma L-tryptophan and the L-tryptophan/CAA ratio were significantly lower in the spring than in the other seasons. The peak-trough differences in the yearly variation expressed as a percentage of the mean were 17.1% and 16.1% for L-tryptophan values and L-tryptophan/CAA ratios, respectively. The amplitude of the yearly variation in all CAAs was low, ie, less than 7%. An important part of the variance in L-tryptophan availability (ie, 12% to 14%) could be explained by the composite effects of present and past climatic factors; higher ambient temperature and relative humidity in the face of lower air pressure are the most important predictors of low L-tryptophan availability. Important and positive time relationships were noted between total serum protein level and all amino acid concentrations, and a significant time relationship was also noted between the seasonal variation in L-tryptophan availability and the occurrence of violent suicide in Belgium. CONCLUSION: Our results show a bimodal seasonal pattern in the availability of plasma L-tryptophan that matches seasonal patterns in the prevalence of violent suicide in the local population and depression in other studies.

Adult↗

PubMed2005

Correlation of stable elevations in striatal mu-opioid receptor availability in detoxified alcoholic patients with alcohol craving: a positron emission tomography study using carbon 11-labeled carfentanil.

BACKGROUND: The pleasant effects of food and alcohol intake are partially mediated by mu-opiate receptors in the ventral striatum, a central area of the brain reward system. Blockade of mu-opiate receptors with naltrexone reduces the relapse risk among some but not all alcoholic individuals. OBJECTIVE: To test the hypothesis that alcohol craving is pronounced among alcoholic individuals with a high availability of mu-opiate receptors in the brain reward system. DESIGN: Patients and comparison sample. The availability of central mu-opiate receptors was measured in vivo with positron emission tomography (PET) and the radioligand carbon 11-labeled carfentanil in the ventral striatum and compared with the severity of alcohol craving as assessed by the Obsessive Compulsive Drinking Scale (OCDS). SETTING: Hospitalized care. PARTICIPANTS: Volunteer sample of 25 male alcohol-dependent inpatients assessed after detoxification of whom 12 underwent PET again 5 weeks later. Control group of 10 healthy men. MAIN OUTCOME MEASURES: After 1 to 3 weeks of abstinence, the availability of mu-opiate receptors in the ventral striatum, including the nucleus accumbens, was significantly elevated in alcoholic patients compared with healthy controls and remained elevated when 12 alcoholic patients had these levels measured 5 weeks later (P<.05 corrected for multiple testing). Higher availability of mu-opiate receptors in this brain area correlated significantly with the intensity of alcohol craving as assessed by the OCDS. CONCLUSIONS: Abstinent alcoholic patients displayed an increase in mu-opiate receptors in the ventral striatum, including the nucleus accumbens, which correlated with the severity of alcohol craving. These findings point to a neuronal correlate of alcohol urges.

Adult↗

PubMed2001

Availability of HIV care in Central America.

Central America is an area with a growing human immunodeficiency virus (HIV) epidemic, but with marked limitations in its health care infrastructure. Estimated adult HIV infection rates range from 0.20% in Nicaragua to 2.01% in Belize. Hospitals and clinicians with experience in HIV care exist mainly, if not only, in capital cities and principal economic centers. Nationally sponsored social security systems in each country consistently offer a wider range of services than do ministry of health systems. Estimated access to the social security system ranges from 0% in Belize and 10% of the population in Honduras to 95% in Costa Rica. Combination antiretroviral therapy is not available through the ministries of health and zidovudine is only sporadically available for prevention of perinatal transmission. Combination therapy is available through the social security system in the countries of Guatemala, Panama, and Costa Rica only. A wide variety of antiretroviral agents are available through private pharmacies in all countries except Belize. With the exception of Costa Ricans, most people with HIV infection in Central America have limited access to HIV-specific health services and limited or no access to antiretroviral agents.

Central America↗

PubMed1999

Reproductive technologies 1998: options available for the cancer patient.

Recent advances in the field of reproduction have potentially opened opportunities for the preservation of the reproductive potential of young cancer patients with good long-term prognosis for survival. In the postpubertal male, cryopreservation of ejaculated sperm is both feasible and potentially successful. Semen parameters at the time of procurement are of minor significance; intracytoplasmic sperm injection (ICSI) can bypass sperm concentration and motility problems and can lead to successful fertilization. For the prepubertal male there are no clinically applicable options insofar as extraction and cryopreservation of postmeiotic sperm cells (mature spermatozoa or round spermatids) is not feasible. To date, efforts for culture of testicular tissue and in vitro maturation of male germ cells have not been successful. In both pre- and postpubertal females, cryopreservation of ovarian cortical tissue or enzymatically extracted follicles and the in vitro maturation of preantral follicles are of potential clinical use, but, to date, these approaches have been successful only in laboratory animals. An additional option available to the postpubertal female is the stimulation of ovaries with exogenous gonadotropins and retrieval of mature oocytes for cryopreservation. The recent application of ICSI in previously cryopreserved human mature oocytes has improved fertilization rates and has resulted in live births. Unfortunately, a shortcoming of this approach is the limited number of oocytes that can be harvested after stimulation of the ovaries. Further, all these approaches potentially harbor the risk of the cryopreservation of malignant cells with their subsequent reintroduction in the patient at a later date. This is a more realistic concern for patients suffering from hematologic or gonadal tumors. Finally, even though cryopreservation of embryos has been successfully used for many years, this option is not available to the pediatric and adolescent patient. It should not be forgotten that, even if the patients' own gametes are not available in the future, donor sperm and eggs provide the option for offspring and can give the opportunity to the females to carry a pregnancy as long as their uterus has not been affected by the cancer treatment. Given the rapid progress we are witnessing in the field of reproductive medicine, it is probable that in the very near future most of the options described and newer ones will be clinically available.

Adolescent↗

PubMed2001

Determination by capillary electrophoresis of total and available niacin in different development stage of raw and processed legumes: comparison with high-performance liquid chromatography.

The available and total niacin evolution during maturation of yellow pea lupine (Lupinus luteus L., cv. Juno), pea (Pisum sativum L., cv. Ergo), faba bean (Vicia faba sp. minor Harz, cv. Tibo) and in germinated and high-pressure heated peas (Pisum sativum L., cv. Esla) have been determined by capillary electrophoresis (CE). The results have been compared with those obtained by high-performance liquid chromatography (HPLC). The values obtained by CE were similar to those obtained by HPLC. Maturation of seeds significantly reduced the available and total niacin content in legumes. The available/total niacin ratio during seed maturation depends on the type of legume. In faba beans and peas, a reduction was observed which was more pronounced in the case of peas. For lupine seeds, the ripening produced an increase (34%) in the available/total niacin ratio 50 days after flowering (DAF). Pea germination produced an overall increase in available and total niacin content although the available/total niacin ratio decreased. High pressure heating of pea yielded an increase in the available niacin content and available/total niacin ratio but the total niacin content did not change.

Chromatography, High Pressure Liquid↗

PubMed2002

Western lowland gorilla diet and resource availability: new evidence, cross-site comparisons, and reflections on indirect sampling methods.

We describe the resource availability and diet of western lowland gorillas (Gorilla gorilla gorilla) from a new study site in the Central African Republic and Republic of Congo based on 3 years of study. The results, based on 715 fecal samples and 617 days of feeding trails, were similar to those reported from three other sites, in spite of differences in herb and fruit availability. Staple foods (consumed year-round) included high-quality herbs (Haumania), swamp herbs (when present), and a minimal diversity of fruit. A variety of fruits (average of 3.5 species per day and 10 per month) were selectively consumed; gorillas ignored some common fruits and incorporated rare fruits to a degree higher than predicted based on availability. During periods of fruit abundance, fruit constituted most of the diet. When succulent fruits were unavailable, gorillas used low-quality herbs (i.e., low-protein), bark, and more fibrous fruits as fallback foods. Fibrous fruit species, such as Duboscia macrocarpa and Klainedoxa gabonensis, were particularly important to gorillas at Mondika and other sites as fallbacks. The densities of these two species are similar across sites for which data are available, in spite of major differences in forest structure, suggesting they may be key species in determining gorilla density. No sex difference in diet was detected. Such little variation in western lowland gorilla diet across sites and between sexes was unexpected and may partly reflect limitations of indirect sampling.

Animals↗

PubMed2006

Do food availability, parasitism, and stress have synergistic effects on red colobus populations living in forest fragments?

Identifying factors that influence animal density is a fundamental goal in ecology that has taken on new importance with the need to develop informed management plans. This is particularly the case for primates as the tropical forest that supports many species is being rapidly converted. We use a system of forest fragments adjacent to Kibale National Park, Uganda, to examine if food availability and parasite infections have synergistic affects on red colobus (Piliocolobus tephrosceles) abundance. Given that the size of primate populations can often respond slowly to environmental changes, we also examined how these factors influenced cortisol levels. To meet these objectives, we monitored gastrointestinal parasites, evaluated fecal cortisol levels, and determined changes in food availability by conducting complete tree inventories in eight fragments in 2000 and 2003. Red colobus populations declined by an average of 21% among the fragments; however, population change ranged from a 25% increase to a 57% decline. The cumulative basal area of food trees declined by an average of 29.5%; however, forest change was highly variable (a 2% gain to a 71% decline). We found that nematode prevalence averaged 58% among fragments (range 29-83%). The change in colobus population size was correlated both with food availability and a number of indices of parasite infections. A path analysis suggests that change in food availability has a strong direct effect on population size, but it also has an indirect effect via parasite infections.

Animals↗

PubMed2006

Availability of pediatric rheumatology training in United States pediatric residencies.

OBJECTIVE: To characterize the availability of pediatric rheumatology training in general pediatric residencies. METHODS: We surveyed 195 pediatric residency program directors in the US using a combined Web-based and paper-based survey format. The survey asked directors about the availability of an on-site pediatric rheumatologist in their institution, the availability of formal pediatric rheumatology rotations, and the types of physicians involved in teaching curriculum components related to pediatric rheumatology. Survey responses were analyzed using descriptive and bivariate statistics. RESULTS: Of the 195 program directors surveyed, 127 (65%) responded. More than 40% of responding programs did not have a pediatric rheumatologist on site. Programs with on-site pediatric rheumatologists were significantly more likely than those without on-site pediatric rheumatologists to have an on-site pediatric rheumatology rotation available (94% versus 9%; P < 0.001). Although pediatric rheumatologists' involvement in 4 curriculum areas relevant to pediatric rheumatology is nearly universal in programs with on-site pediatric rheumatologists, nearly two-thirds of programs without on-site pediatric rheumatologists rely on internist rheumatologists, general pediatricians, or other physicians to cover these areas. CONCLUSION: Programs without pediatric rheumatologists on site are less likely to have pediatric rheumatology rotations and are more likely to rely on internist rheumatologists and nonrheumatologists to address rheumatology-related curriculum components. Lack of exposure to pediatric rheumatology during residency may impede general pediatricians' ability to identify and treat children with rheumatic diseases, undermine resident interest in this field, and perpetuate low levels of supply.

Child↗

PubMed1992

Body measurements, estrogen availability and the risk of human breast cancer: a case-control study.

Recent studies on lifestyle-related mechanisms involved in cardiovascular risk offer important clues for a better understanding of breast-cancer epidemiology. Central body-fat distribution promoted by an affluent dietary intake and a sedentary lifestyle over many years is related to elevated serum triglycerides and free fatty acids, with lower levels of sex-hormone-binding globulin (SHBG). The resulting greater availability of estradiol not bound to SHBG could help to explain the high breast-cancer incidence in Western industrialized countries. We conducted a case-control study comparing 225 women aged 38 to 75 years with operable (stage I or II) breast cancer and 441 women of the same age having no breast cancer who participated in a population-based breast-cancer screening program. Body fatness, as measured by body mass index (BMI), fat distribution as measured by waist-to-hip girth ratio (WHR), body height, serum lipids, SHBG and the available fraction of estradiol were analyzed in a conditional logistic regression, together with family history for breast cancer, reproductive history and smoking. Post-menopausal cases showed no difference in body fatness (BMI), but a significant preponderance of central adiposity (WHR). In contrast, pre-menopausal cases were significantly leaner, but had a similar body-fat distribution as compared with controls. In all women, WHR, and less strongly BMI, was positively correlated with serum levels of triglycerides and available estradiol fractions. An independent, positive linear correlation between body height and relative risk (RR) was observed. Moreover, a significant correlation between SHBG and menarcheal age was seen in cases, but not in controls. These data support our hypothesis that lifestyle relates to breast-cancer risk by metabolic-endocrine mechanisms which modulate the availability of individual sex-steroid concentrations in plasma. The findings of height as a risk factor and adult SHBG levels being correlated with menarcheal age suggest that lifestyle factors promoting breast-cancer development already act around puberty. The leanness of pre-menopausal cases awaits further explanation.

Adult↗

PubMed1989

Availability and timing of new drugs in Israel: analysis and international comparison.

Whereas the latest data suggest that the number of new chemical entities (NCE) launches worldwide may be on the increase, both recent and longer term data show a decline in the rate of NCE introductions into Israel. In terms of percentage availability, only 30% of NCEs available worldwide during 1978-1987 were introduced in Israel during the same period, compared with 42% for the U.S.A. In both countries there has been a decreasing percentage availability since 1983/84. The percentage availability of commercially significant NCEs was greater (47%) compared to all NCEs introduced in Israel. Whereas in the U.S.A. the lower the therapeutic rating the higher the proportion of NCEs, in Israel the B- and C-rated drugs were equally represented. NCEs with an A-rating had a similar share of all NCEs (ca 15%) in both countries. The average time lag for NCEs launched worldwide to reach Israel during 1978-1987 was 4 to 5 years, but in recent years there has been a considerable decline. Commercially significant NCEs introduced in Israel had on average a shorter time lag of 0.5 years than the average for all NCEs introduced. In spite of a preponderance of NCEs first launched in the U.S.A. there was on average a slight relative lag into the U.S.A. compared to Israel. This was probably due to there being a number of NCEs first introduced in Israel with a long delay before they were subsequently approved in the U.S.A.(ABSTRACT TRUNCATED AT 250 WORDS)

Drugs, Investigational↗

PubMed2005

Limiting iron availability confers neuroprotection from chronic mild carbon monoxide exposure in the developing auditory system of the rat.

Iron deficiency and chronic mild carbon monoxide (CO) exposure are nutritional and environmental problems that can be experienced simultaneously. We examined the effects of chronic mild CO exposure and iron availability on auditory development in the rat. We propose that chronic mild CO exposure creates an oxidative stress condition that impairs the spiral ganglion neurons. The CO-exposed rat pups had decreased neurofilament proteins and increased copper, zinc-superoxide dismutase (SOD1) in the spiral ganglion neurons. We conclude that the increased amount of SOD1 causes an increase in hydrogen peroxide production that allows the Fenton reaction to occur. This reaction uses both iron and hydrogen peroxide to generate hydroxyl radicals and leads to the development of oxidative stress that impairs neuronal integrity. However, rat pups with decreased iron and CO exposure (ARIDCO) exhibited in their cochlea an up-regulation of transferrin, whereas their expression of neurofilament proteins and SOD1 were similar to control. Consequently, reduced iron availability and the normal expression of SOD1 do not promote oxidative stress in the cochlea. By using basal c-Fos expression as a marker for cellular activation we found a significant reduction in c-Fos expression in the central nucleus of the inferior colliculus in iron-adequate rat pups exposed to CO. By contrast, rather than being reduced, c-Fos expression in the ARIDCO group is the same as for controls. We conclude that the cochlea of rat pups with normal iron availability is selectively affected by mild CO exposure, causing a chronic oxidative stress, whereas limiting iron availability ameliorates the effect caused by mild CO exposure by averting conditions that facilitate oxidative stress.

Animals↗

PubMed1994

The paired availability design: a proposal for evaluating epidural analgesia during labor.

The paired availability design (PAD) can reduce selection bias when it is not possible to randomize subjects. PAD consists of independent pairs of experimental and control groups. Within each pair, the intervention is the availability of treatment not its receipt. In the experimental group, the new treatment is made available to all subjects although some may not receive it. In the control group, the experimental treatment is generally not available to subjects although some may receive it in special circumstances. We present a statistic to test a null hypothesis that the receipt of intervention will increase response by a specified non-zero amount delta. We propose this design for use in a study of the effect of epidural analgesia on the rate of Caesarean section.

Adult↗

PubMed1999

FGF receptor availability regulates skeletal myogenesis.

Fibroblast growth factors (FGFs) and their receptors are critical participants in embryonic development, including the genesis of skeletal, cardiac, and smooth muscle. FGF signaling is mediated through interactions between multiple FGF ligands and transmembrane tyrosine kinase receptors, resulting in activation of a number of signal transduction pathways. Skeletal myocytes express FGF ligands and receptors in a coordinated fashion, suggesting that these molecules participate in autocrine signaling in the myocyte. Endogenously produced FGF has been shown to inhibit myogenesis, but the role of FGF receptor availability in directing myocyte proliferation and differentiation has not been established. To determine the contribution of receptor availability to the regulation of myogenesis, receptor availability was either increased by expressing a full-length FGF receptor-1 or decreased by expressing a truncated FGF receptor-1 in cultured skeletal myocytes. Constitutive expression of a full-length FGF receptor-1 increased myocyte proliferation and delayed differentiation. Conversely, a reduction in functional FGF receptor signaling by expression of a truncated FGF receptor-1 decreased proliferation and enhanced differentiation of myocytes. These data demonstrate that FGF receptor availability plays a critical regulatory role in skeletal myogenesis.

Animals↗