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Biomedical subjects

L Sibley

Publications and source records attributed to L Sibley.

18 recordsLinked to original sources
PubMed2006

Sustained high levels of stored drinking water treatment and retention of hand-washing knowledge in rural Kenyan households following a clinic-based intervention.

Nyanza Province, Kenya is characterized by poor water quality and high diarrhoea prevalence. To address these problems, nurses in a maternal and child health clinic in Homa Bay, Kenya were trained in household water chlorination with a locally available, social marketed product, and in six steps of proper hand washing. They were asked to communicate this information to their clients. Interviews immediately following the training by nurses were conducted on 220 clients, of whom 168 (76%) reported being taught both procedures during their clinic visit. After 2 weeks, free chlorine residuals were present in stored drinking water in 67 out of 98 (68%) clients' homes and, 1 year later, in 36 out of 51 (71%) clients' homes. After 2 weeks, all six hand-washing steps were correctly demonstrated by 41 (44%) out of 93 clients, and by 17 out of 51 (34%) 1 year later. This brief, practical intervention shows promise for vulnerable populations.

Adolescent↗
PubMed2005

Addressing the challenges of the global nursing community.

AIM: To describe both the initial and the subsequent impact of the 2001 Global Nursing Partnerships Conference: 'Strategies for a Sustainable Workforce', the first ever forum of its type, on the key challenges facing the global nursing community. DESIGN: Identification of short- and long-term outcomes through descriptive review of immediate post-conference evaluations and follow-up questionnaires sent out 13 months later to nursing leaders in the participating countries. METHODS: Content analysis of quantitative data from 61 immediate post-conference evaluations and 13 follow-up questionnaires, as well as qualitative data from participant comments on the evaluation forms and questionnaires. FINDINGS: Analysis indicated conference participants viewed the conference as a beneficial forum to collaboratively examine nursing workforce issues and trends, develop country-specific nursing action plans, establish and strengthen national and international partnerships, and build stronger international nursing bodies. CONCLUSION: The Global Nursing Partnerships Conference was an international success--addressing the unique challenges facing nursing leaders in developed and developing countries and the needs of nurses throughout the world.

Congresses as Topic↗
PubMed1994

Interstitial exclusion of IgG in rat tissues estimated by continuous infusion.

Interstitial exclusion, defined as the fraction of interstitial fluid volume inaccessible to a solute, was evaluated for immunoglobulin G (IgG) in selected tissues of rats by a method previously applied to serum albumin (29). IgG distribution volumes were also measured for intestine. 125I-labeled rat IgG was infused for 5 or 7 days (n = 4 rats each) with an implanted osmotic pump (Alzet). At the termination of infusion, the rat was anesthetized, nephrectomized, and injected with 51Cr-labeled EDTA (4 h) to label total extracellular fluid volume and 131I-labeled bovine IgG (5 min) to label plasma volume. Samples of skin, muscle, and tendon were assayed for total and extractable tracer activity. Interstitial fluid from these tissues was sampled postmortem with nylon wicks for assay of 125I-labeled IgG and endogenous albumin and IgG. Exclusion of IgG was calculated from the difference between extravascular 125I-labeled IgG and 51Cr-labeled EDTA distribution volumes. In contrast to our previous experience with tracer albumin, 125I-labeled IgG was not fully extractable from minced skin, muscle, or tendon by isotonic saline; only 71-83% was recovered under conditions that eluted 92-96% of tracer albumin and 94-99% of tracer EDTA. We conclude that approximately 20% of extravascular 125I-labeled IgG in these tissues is sequestered or bound in the interstitium. Calculation of IgG fractional exclusion from extractable tracer yielded the following values (means +/- SE, n = 8 rats): leg muscles 0.37 +/- 0.09, leg skin 0.44 +/- 0.03, back skin 0.36 +/- 0.04, tail skin 0.40 +/- 0.08, and tail tendon 0.55 +/- 0.04.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Blood-tissue transport of exogenous albumin and immunoglobulin G in genetically analbuminemic rats.

Tracer uptake studies were carried out in adult female Nagase (NA) strain analbuminemic rats [derived from Sprague-Dawley (SD) stock] and in adult female SD controls to determine the extent to which capillary permeability to plasma proteins is altered in the absence of endogenous albumin. Accessory measurements (arterial pressure, central venous pressure, plasma and interstitial fluid protein concentrations and oncotic pressures, plasma volume, and interstitial fluid volume) confirm the report of Joles et al. [Am. J. Physiol. 257 (Renal Fluid Electrolyte Physiol. 26): F23-F28, 1989] that shows elevated plasma volumes, normal interstitial fluid volumes, nearly normal plasma oncotic pressures (due to elevated globulin concentrations), and lower interstitial fluid oncotic pressures. In skin, skeletal muscles, and heart muscle, clearances of exogenous heterologous (bovine) albumin were 20-40% higher in NA than in SD controls. In intestine, albumin clearances were 20-30% lower. In NA rats blood-to-tissue clearances of heterologous (bovine) immunoglobulin G in skin and heart were higher and in the intestine they were lower than in SD controls; however, clearances in skeletal muscles were not elevated. The differences between NA and SD are small compared with the large increases in macromolecular permeabilities reported by others for organs and single microvessels perfused with albumin-free fluids.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1992

Biocultural synthesis in medical anthropology.

Medical anthropology has developed distinct and separate biological and cultural approaches to the study of health and disease in human populations. Within cultural anthropology a major focus has been the ethnomedical perspective that analyzes the process of defining disease and describing the social response to disease. In biological anthropology, an ecological perspective considers the interaction of the population, the insult and the environment at the core of the disease process. There has been limited success in integrating the cultural and biological perspective. Some cultural anthropologists claim that the ecological perspective relies on a biomedical model and therefore is not useful in studying non-Western societies. Others are critical of the adaptivist perspective that they believe fails to consider political economic factors that affect the disease process. The lack of a biocultural integration has hindered the systematic analysis of health and disease in contemporary traditional and non-Western groups. An ecological model that addresses these problems will provide a biocultural integration of the disease process.

Adaptation, Psychological↗
PubMed1992

Plasma volume expansion with colloids increases blood-tissue albumin transport.

Extravasation of plasma proteins is increased after volume expansion with whole blood or plasma. To investigate the mechanisms responsible for this phenomenon, we measured extravascular accumulation of exogenous 131I-labeled bovine serum albumin in several tissues and organs of anesthetized rats. Plasma volume was increased acutely by infusion of isoncotic albumin or polyvinylpyrrolidone, with or without subsequent infusion of a 1:10 dilution of the colloid to induce blood-to-tissue fluid movement. Controls were given only a slow sustaining infusion of saline. The amounts of fluid and plasma protein lost from the circulation were followed simultaneously by two methods: 1) material balance in the whole animal, and 2) changes in 131I-labeled albumin uptake (VA) and water content (VW) in the individual tissues. Plasma volume expansion of 80-90% increased plasma protein extravasation in the whole rat by an average of 2.7-fold over a 30-min period. Of the protein extravasated, 42% entered the abdominal cavity. The rest was distributed in the interstitial compartment of various tissues and organs. Tracer albumin accumulation (averaged over 30 min) was increased 38-82% in skin and paw, 40-59% in skeletal muscles, 131% in hearts, and 167-230% in different parts of the intestine. Increased convective transport does not appear to be a major factor. There was little or no relation of albumin transport increase to the magnitude or direction of net fluid transfer. Coupling of albumin transport to volume flow was not greater than previously reported for saline infusion or venous congestion. Convective redistribution (convective transport without net fluid transfer, "volume recirculation") is estimated to increase albumin transport no more than 10% under the conditions of our experiments. The greater part of the increase is thus dissipative, i.e., attributable to increased diffusion or increased vesicular exchange. Control of dissipative transport of albumin may play an important role in regulating plasma volume.

Animals↗
PubMed1992

Interstitial exclusion of albumin in rat tissues measured by a continuous infusion method.

Steady-state 125I-labeled rat serum albumin (125I-labeled RSA) concentration in plasma was maintained by intravenous infusion of tracer for 72-168 h with an implanted osmotic pump. At the end of the infusion period, the rat was anesthetized and nephrectomized, and extracellular fluid was equilibrated with intravenous 51Cr-labeled EDTA for 4 h. Five minutes before final plasma and tissue sampling, 131I-labeled bovine serum albumin (131I-labeled BSA) was injected intravenously as a plasma volume marker. Samples of skin, muscle, tendon, and intestine were assayed for all three tracers. Apparent distribution volumes were calculated as tissue tracer content/plasma tracer concentration. Interstitial fluid volume (Vi) was calculated as V51Cr-EDTA-V131I-BSA. Steady-state extravascular distribution of 125I-labeled RSA as plasma equivalent volume (Va,p) was calculated as V125I-RSA-V131I-BSA. Steady-state interstitial fluid concentrations of 125I-labeled RSA in skin, muscles, and tendon were measured with nylon wicks implanted postmortem, and steady-state interstitial albumin distribution volumes were recalculated as wick-fluid equivalent volumes (Va,w). Relative albumin exclusion fraction (Ve/Vi) was calculated as 1-Va,w/Vi. For skin and muscle, steady-state 125I-labeled RSA tissue concentrations were reached at 72 h. Ve/Vi for albumin averaged 26% in hindlimb muscle, 41% in hindlimb skin, 30% in back skin, 39% in tail skin, and 54% in tail tendon. For muscle, Ve/Vi corresponds to expectation if all tissue collagen and hyaluronan is dispersed in the interstitium. However, for skin and tendon, albumin exclusion is considerably lower than expected on this basis, suggesting that much of their collagen is organized into dense bundles of fibers containing no fluid accessible to 51Cr-labeled EDTA or 125I-labeled RSA.

Animals↗
PubMed1991

Sampling interstitial fluid from rat skeletal muscles by intermuscular wicks.

A modification of the implanted wick method (K. Aukland and H. O. Fadnes. Acta Physiol. Scand. 88: 350-358, 1973) was devised to sample interstitial fluid from rat muscles. Dry nylon wicks were inserted postmortem into intermuscular spaces between leg muscles by means of a plastic catheter, which was subsequently withdrawn. Inserting the wicks postmortem avoids contaminating wick fluid with proteins extravasated as a result of local inflammatory reactions; placing them intermuscularly avoids contamination by fluid and proteins from damaged muscle cells. Wick fluid protein concentrations (mg/ml) averaged 24.1 +/- 1.1 and 28.5 +/- 1.5 (means +/- SE) in medial and lateral hindlimbs muscles, respectively. The corresponding albumin concentrations were 13.0 +/- 0.7 and 13.9 +/- 0.7 mg/ml. Total protein and albumin concentrations in plasma were 54.1 +/- 0.8 and 22.5 +/- 0.3 mg/ml. Electrophoresis of wick fluid showed a pattern of peaks similar to that of plasma, with albumin relatively high and larger molecules relatively low. Proteins from muscle cells were not detected. Isotope studies (125I-labeled albumin, 51Cr-EDTA) showed that less than 2% of the albumin in wick fluid came directly from plasma and that wick fluid was not concentrated by cell swelling postmortem. Wick fluid from intermuscular wicks implanted in anesthetized rats in vivo had nearly the same total protein concentration as fluid from postmortem wicks, but albumin-to-globulin (A/G) ratios were slightly lower (1.22 +/- 0.07 vs. 1.53 +/- 0.21 measured by gel electrophoresis), and more significantly, nearly 50% of the albumin leaked to wick fluid from plasma as a result of wick implantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Influence of saline infusion on blood-tissue albumin transport.

Anesthetized rats were infused with lactated Ringer solution (LR) at constant rate for 30 or 60 min; delivered volume loads ranged from 0.03 to 0.08 ml/g body wt. Controls were given only a sustaining infusion of saline at 0.002 ml.g-1.h-1. Only 7-14% of the LR remained in the plasma at the end of the infusion; 76-88% entered the interstitial compartment, and 7-17% was excreted. The amount of plasma protein lost from the circulation with the extravasated fluid was studied simultaneously by two methods: 1) material balance in the whole animal and 2) changes in 131I-labeled albumin uptake (VA) and water content (VW) in individual tissues. The extravasation of 0.03-0.06 ml fluid/g body wt (75-160% initial plasma volume) did not significantly increase plasma protein extravasation in the whole rat. Nearly all of the sampled tissues of LR-infused rats had higher VW than controls. Tissue VA tended to increase with VW, but the regression slopes (delta VA/delta VW), a measure of the tracer albumin concentration of capillary filtrate relative to plasma, were low; skin, 0.006; paw, 0.018; skeletal muscles, 0.007; heart, 0.057; jejunum, 0.095; ileum, 0.045; cecum, 0.026; and colon, 0.027. These ratios are consistent with the very small loss of total plasma protein observed and attest to high solvent-drag reflection coefficients (sigma approximately equal to 1 - delta VA/delta VW): greater than 0.98 in capillaries of skeletal muscles, skin, and paw and 0.91-0.97 in heart and intestine.

Animals↗
PubMed1989

Albumin extravasation rates in tissues of anesthetized and unanesthetized rats.

Bovine serum albumin (BSA) labeled with 131I was injected intravenously in chronically prepared, unanesthetized rats and into pentobarbital-anesthetized rats that had received 2 ml 5% BSA to help sustain plasma volume. Initial uptake rates (clearances) in skin, skeletal muscles, diaphragm, and heart (left ventricle) were measured over 1 h. BSA labeled with 125I was injected terminally to correct for intravascular 131I-BSA. Observed clearances were in the following order in both groups of animals: heart much greater than diaphragm approximately equal to skin greater than resting skeletal muscles. Differences between unanesthetized and anesthetized animals were small and inconsistently directed. Our results suggest that the lower albumin clearances reported in the literature for anesthetized rats are not the result of their immobility or any direct effect of anesthesia on albumin transport in these tissues. The lower transport rates appear to result indirectly from changes produced by anesthesia and/or surgery in controllable parameters such as plasma volume and intravascular protein mass.

Anesthesia, General↗
PubMed1988

Coupling of albumin flux to volume flow in skin and muscles of anesthetized rats.

Bovine serum albumin (BSA) labeled with 131I or 125I was injected intravenously in pentobarbital sodium-anesthetized rats, and tracer clearances into leg skin and muscles were measured over 30, 60, and 120 min. BSA labeled with the alternate tracer was used as vascular volume reference. Two minutes before injection of the tracer, a ligature was tied around one femoral vein to occlude outflow partially and raise capillary pressure in that leg. The unoccluded leg served as control. Skin and muscles of the occluded leg had variably and substantially higher water contents (delta W) than paired control tissues and slightly but consistently increased albumin clearances (CA). The delta CA/delta W, equivalent to the albumin concentration of capillary filtrate relative to plasma determined by linear regression, were as follows: leg skin 0.004 (95% confidence limits -0.001 to +0.009), muscle biceps femoris 0.005 (0.001-0.010), muscle gastrocnemius 0.011 (0.004-0.019), muscle tibialis anterior 0.016 (0.012-0.021). All these values are significantly less than 0.10, which corresponds to a reflection coefficient for serum albumin (sigma A) of 0.90. Convective coupling of albumin flux to volume flux in skin and muscles of intact, anesthetized rats is low, with sigma AS in the range 0.98 to greater than 0.99.

Animals↗
PubMed1987

Acute effects of iron therapy on zinc status during pregnancy.

The acute effects of iron therapy on zinc status during pregnancy were investigated. The 20 subjects studied were healthy and had unremarkable obstetric histories. The mean stage of gestation was 27 weeks (range 21-33 weeks). Initial hematologic indices (mean +/- SEM) were: hematocrit 36.5 +/- 0.4%, serum ferritin 32.6 +/- 6.1 ng/mL, and serum iron 117 +/- 13 micrograms/dL. Iron therapy, prescribed by the obstetric caregivers, provided a total average daily elemental iron intake of 261 mg (range 164-395 mg) from therapy and routine supplements. Laboratory studies of zinc status were obtained immediately before iron therapy and at one and four weeks thereafter. Initial plasma zinc was 62.9 +/- 2.1 micrograms/dL. A mean decline in plasma zinc of 4.0 +/- 1.8 micrograms/dL (P less than .05) was observed from baseline to one week. The decline remained statistically significant after adjustment for the expected physiologic decline over the same interval of gestation. No further decline occurred from one to four weeks. No significant treatment-related effects were observed for neutrophil zinc, mononuclear leukocyte zinc, or serum alkaline phosphatase activity. These results indicate that iron therapy in doses typically prescribed by obstetric caregivers in this country has an acute, measurable effect on maternal zinc status.

Adult↗
PubMed1986

Wick sampling of interstitial fluid in rat skin: further analysis and modifications of the method.

UNLABELLED: We compared modifications of the wick technique for analysis of interstitial fluid in rat subcutis. Nylon wicks were implanted for 60 min in back skin of rats after anesthesia with pentobarbital or after sacrifice by potassium chloride injection. Wicks were implanted dry or loaded with saline or varied dilutions of rat serum. Implantation of dry wicks and wicks loaded with diluted serum in living, anesthetized animals produced similar results; the protein concentration of wick fluid averaged about 60% that of the plasma protein concentration. The saline loaded wicks produced wick fluid with a lower protein concentration, average about 45% that of plasma protein concentration. The lower concentrations apparently resulted from simple dilution. Wick fluid sampled from dead animals had similar total protein concentrations, but in the dead animals there was a lower concentration of the large plasma proteins and a relatively higher concentration of the smaller proteins. CONCLUSIONS: Wick implantation in living animals causes a transitory inflammatory reaction and a decrease in the size selectivity of macromolecular sieving, but local osmotic forces bring about a concentration equilibrium with undisturbed interstitium. Implantation of dry wicks in subcutis either in vivo or post mortem provides a simple, direct method for sampling the total protein concentration and colloid osmotic pressure of interstitial fluid. Implantation of dry wicks postmortem permits measurement of individual component protein concentrations and evaluation of molecular selectivity between plasma and interstitium.

Animals↗
PubMed1984

Small-volume resuscitation with hypertonic saline (2,400 mOsm/liter) during hemorrhagic shock.

We compared small-volume resuscitation using either normal saline or hypertonic saline (2400 mOsm/liter) during hemorrhagic hypotension. Six unanesthetized sheep were bled to 50 mm Hg mean arterial pressure and maintained for 2 h. During this shock period cardiac output decreased 40-50% of baseline, while total peripheral resistance increased 20-30%. Then the response to a bolus injection of either hypertonic saline or normal saline, randomly chosen, was studied for an additional 2 h. The volume injected was 145-175 ml, equal to 10% of total shed blood volume. After data collection all shed blood was returned. Several days later, the protocol was repeated on each sheep with the alternate solution. After hypertonic saline the mean arterial pressure increased 48 mm Hg to 83% of control; with normal saline, mean arterial pressure increased 26 mm Hg. Cardiac output recovered to 95% of control immediately after infusion of hypertonic saline, while no significant increase was observed with normal saline. Ten minutes after injection of hypertonic saline, plasma volume increased approximately 360 ml, but with normal saline no increase was observed. We conclude that small-volume injection of hypertonic saline can dramatically improve circulatory function during hemorrhagic shock, as evidenced by expansion of plasma volume, increased cardiac output, and reduced peripheral resistance.

Animals↗
PubMedDate not supplied

Obstetric first aid in the community--partners in safe motherhood. A strategy for reducing maternal mortality.

The unacceptably high levels of maternal mortality that are prevalent throughout the developing world are a product of many factors; most notably, these include nonexistent, inaccessible or inadequate facility-based emergency care, poorly developed referral linkages, predominance of home-based care by attendants and family members who are poorly equipped to respond to emergencies, and the complexities of problem recognition and decision making during emergencies leading to inappropriate or delayed action. This paper describes an innovative community-oriented strategy that has been designed to reduce maternal mortality and that targets women, families, and traditional birth attendants (TBAs) using two complimentary training interventions. The strategy reflects the authors' conviction that the training of professional and paraprofessional health workers in emergency care is essential, but that it must be complemented by the education and mobilization of families, communities, and TBAs who must, in turn, come to common perceptions on the need for and means of intervening to prevent a maternal death. Collaborating with partners in the US Agency for International Development-funded Primary Providers Training and Education in Reproductive Health Project. Special Project staff of the American College of Nurse-Midwives will lead development and testing of the strategy through operations research activities in selected countries.

Community Health Services↗
PubMedDate not supplied

Home based life saving skills: promoting safe motherhood through innovative community-based interventions.

In much of the developing world, home birth with unskilled attendants is the norm, and maternal and neonatal mortality rates are high. A comprehensive approach to address this problem needs to upgrade referral facilities and strengthen the skills of trained health care providers. To improve pregnancy outcomes, a program must also provide education, motivation, and mobilization of pregnant women, families, and communities (whose members must come to a common understanding of the need for and the means to prevent death of a woman or neonate). Consequently, the American College of Nurse Midwives (ACNM) has expanded the Life Savings Skills Series to include Home Based Life Saving Skills (HBLSS). HBLSS is a community and competency-based program that aims to reduce maternal and neonatal mortality by increasing access to basic life saving measures within the home and community and by decreasing delays in reaching referral facilities where life-threatening problems can be managed.

Community Health Services↗