Biomedical subjects

J D Osterloh

Publications and source records attributed to J D Osterloh.

At least 19 recordsLinked to original sources

PubMed1999

Study of the effect of lactational bone loss on blood lead concentrations in humans.

Lactation and other clinical states of high bone turnover have been suggested to release lead (Pb) stored in bone into blood and tissues. Previous observations on the influences of lactation have been anecdotal, or at high blood Pb concentrations with varying past exposures, or complicated by postpartum fluid changes. A prospective observational study was performed to investigate possible changes in blood lead concentrations at multiple intervals during lactation for 6 months postpartum and to relate changes in blood lead concentrations to changes in bone density and other variables. Volunteer pregnant subjects (n = 58) were enrolled from a midwifery service at an academic public health hospital. Subjects were mostly Hispanic, recently immigrated, of low economic status, not receiving supplemental calcium, and had low blood Pb concentrations (2.35 +/- 2.05 microg/dl at enrollment). Bone density losses over 6 months for the group averaged -2.46 +/- 6.33% at the vertebral spine and -0.67 +/- 5.21% at the femoral neck. In predicting final bone density, apart from initial bone density only the total number of breast-feedings was a significant independent variable of the variables tested, accounting for an additional 12% of the variability. No changes in blood Pb concentrations were seen over the interval beyond 2 weeks postpartum (minimum detectable change was 0.4 microg/dl). There was no relation between the changes in bone density and changes in blood Pb or the integrated blood Pb over the 2-week to 6-month period. Normal (nonlactating) bone resorption rates contribute a large fraction of the Pb in blood during low-exposure circumstances. However, during lactation the increase in bone resorptive processes is probably relatively small with a larger decrease in deposition accounting for net bone loss, as suggested by other investigations. Thus, concomitant release of Pb from bones of lactating subjects with low blood lead concentrations on this background of high normal resorption was not large enough for detection.

Adult↗

PubMed1998

Methodological considerations for the accurate determination of lead in human plasma and serum.

Studies which accurately measure plasma or serum lead (Pb) are needed to evaluate the 'biologically active' fraction of Pb in the circulation, and to clarify the role of plasma in the transportation of Pb between different compartments of the body. We evaluated several methodological aspects which influence the determination of Pb in plasma and serum. Generally, venous blood was obtained by different sampling methods (routine and ultraclean) from 3 subjects without history of Pb exposure. After centrifugation (800 g) for 10 min, the plasma or serum was analyzed by inductively coupled plasma-high-resolution mass spectrometry (ICP-MS). Several evaluations were conducted, including 1) comparison of an ultraclean serum collection method with a plasma collection method that used a commercial Vacutainer-type tube for trace metals (EDTA anticoagulant); 2) the effect of whole blood standing time prior to centrifugation on plasma or serum Pb concentration; and 3) comparison of a method using commercial heparinized Vacutainer tubes to an ultraclean plasma sampling method that utilized a low-Pb heparin anticoagulant. Plasma or serum iron (Fe) levels were also measured to evaluate hemolysis. The 3 subjects had whole blood Pb (blood-Pb) levels of 1.8, 2.0, and 2.7 micrograms/dl. Their corresponding ultraclean serum-Pb levels were 0.40%, 0.30%, and 0.48% of their whole blood-Pb levels, respectively. By comparison, the EDTA Vacutainer method plasma-Pb values were 1.7%, 1.5%, and 2.4% of whole blood-Pb, respectively. Whole blood standing (clotting) times of 15, 40, and 70 min before centrifugation resulted in increasing ultraclean serum-Pb levels of 0.21%, 0.81%, and 1.2% of whole blood-Pb (1.8 micrograms/dl), respectively. Whole blood standing time had no effect on plasma-Pb levels when heparin Vacutainers were used, or when a low-Pb heparin was used to obtain ultraclean plasma. However, plasma collected using the commercial heparin Vacutainer method contained consistently higher and more variable Pb levels than samples collected using the ultraclean plasma-Pb method. Hemolysis, when present, contributed significantly to both plasma-Pb and serum-Pb levels. In conclusion, plasma-Pb and serum-Pb levels are dependent upon methodologic processing techniques, including Pb contamination control, redistribution due to EDTA anticoagulant, hemolysis, and time dependency in sample processing. While true plasma-Pb and serum-Pb levels by any method have yet to be defined, these data provide a methodological basis from which to investigate variation in Pb partitioning between whole blood and plasma within individuals.

Adult↗

PubMed1997

Indium as internal standard in square wave anodic stripping analysis of lead in blood with microelectrode arrays.

The toxic effects of lead on humans, especially children have been well documented. ASV has been an important technique in the analysis of lead in blood of humans. This research has demonstrated that indium(III) can be used as an internal standard in the analysis of lead in blood samples with mercury film microelectrode arrays. Indium is a good choice because of a low endogenous blood concentration and because baseline separation of anodic stripping peaks among Cd, In, and Pb can be achieved under appropriate conditions. The concentration of sodium bromide strongly influences the resolution of these metals and the sensitivity of ASV to In(III) in solution. Square wave anodic stripping voltammetry together with screen-printed microelectrode arrays showed that the ratio of the anodic stripping peak currents of Pb and In varies linearly with the concentration of Pb in blood samples ranging from 1.2 to 30.0 micrograms/dL. The average intraassay precision (rsd) was 6.7%.

Electrochemistry↗

PubMed1996

Serum concentrations of methanol after inhalation at 200 ppm.

Methanol has been proposed as an alternative automotive fuel to reduce pollution in the urban environment. Utilization of methanol will increase exposure to low levels of methanol vapors for the general public and in occupational settings. Information on absorption by inhalation and serum concentrations after low-level exposure would be important in evaluating the health impact of generalized methanol exposure. During a randomized double-blind study of the potential neurobehavioral effects of inhaled methanol at 200 ppm for 4 hours, 15 timed specimens from 22 subjects were obtained for methanol analysis by head-space gas chromatography. Methanol was rapidly absorbed by inhalation (absorption rate constant = 0.87 +/- 0.60 hours-1). Serum methanol concentrations were increased by more than fourfold at the end of the exposure period (6.5 +/- 2.7 vs 0.9 +/- 0.6 mg/L), as were urinary methanol excretion rates, although formate concentrations were not increased over background concentrations. The overall (n = 22) elimination half-life was 3.2 +/- 2.3 hours. Elimination from plasma fit a monoexponential model for only half of the subjects during the 4-hour postexposure follow-up period (mean half-life = 2.2 hours). Subjects with poor fits either showed greater variability or apparent slow (nonsignificant) declines in serum methanol concentrations, possibly because of the offsetting contributions of dietary intake or endogenous production, but more likely as a result of the limited number of sampling times and limited follow-up period.

Adult↗

PubMed1996

Use of endogenous, stable lead isotopes to determine release of lead from the skeleton.

The stable lead isotope methodology can be used to study the release of lead from bone into the circulation because of its potential to distinguish circulatory lead from "older" and isotopically different skeletal lead that may have been accumulated years or decades earlier. Here we report the initial results from a larger ongoing study that evaluates the skeleton as a source of lead to the circulation in environmentally exposed human subjects. Lead concentrations and stable lead isotopic compositions were measured in blood and trabecular bone samples obtained from five patients who underwent total hip or knee joint replacement. All subjects contained low blood (1-6 micrograms/dl) and bone (0.6-7 micrograms/g dry weight) lead concentrations typical of environmentally exposed individuals. There were relatively large differences in the lead isotopic compositions between the paired blood and bone samples from each subject. These isotopic differences are attributed to differences in the lead isotopic compositions of past versus current lead exposures and to the long elimination half-life of lead in the skeleton compared to lead in the circulation. Based on these data, we determined that the skeleton contributed 40-70% of the lead in the blood of these subjects. This initial study demonstrates the utility of the stable lead isotope methodology for investigating the release of lead from the skeleton. It also shows that the skeleton can be an important endogenous source of lead exposure in environmentally exposed humans.

Aged↗

PubMed1996

Discrepancies in osmolal gaps and calculated alcohol concentrations.

OBJECTIVES: To estimate unexplained osmolal gaps (UEOG) during ethanol ingestions after accounting for measured ethanol concentrations and to explore the causes of observed discrepancies. DESIGN AND SPECIMENS: A random convenience sample of serum specimens with a request to perform osmometry for the detection of alcohols was studied. MAIN OUTCOME MEASURES: Serum concentrations of sodium, glucose, urea nitrogen, ethanol, osmolality, and ethanol were measured by two analytic methods to determine calculated osmolalities and osmolal gaps using two commonly used formulas. RESULTS: In 79 serum specimens submitted for osmometry, mean ethanol concentrations were 199 +/- 154 (SD) mg/dL; 15 specimens had no detectable ethanol. After regression of the calculated ethanol concentrations and the measured ethanol concentrations, the Dorwart and Chalmers formula showed a large constant bias of 45.217 +/- 6.414 (SE) mOsm/kg in predicting measured ethanol concentrations. The Smithline and Gardner formula was similarly as precise (r = .9786), but had a much smaller bias of -3.929 +/- 6.623 (SE) mOsm/kg. Actual mean differences between measured and calculated osmolalities (including ethanol osmols) gave an estimate of UEOG seen during ethanol ingestions. Using the less biased formula, the mean UEOG was 1.4 +/- 8.5 mOsm/kg, giving a 95% upper limit of the reference range of 18 mOsm/kg in this population with ethanol ingestions. Three significant outliers were identified and their UEOG could be explained by the presence of mannitol, isopropanol, or possibly a change in the assumed value for fractional water, normally a constant in these formulas for calculated osmolality. Other specific causes of osmolal gap and UEOG are discussed. CONCLUSION: The potential range of osmolal gaps seen during ethanol ingestions after accounting for ethanol is demonstrated to be greater than in previous studies, which have included a lower proportion of ethanol-intoxicated subjects in their study sample.

1-Propanol↗

PubMed1995

Electrochemical determination of low blood lead concentrations with a disposable carbon microarray electrode.

Lead concentrations in blood samples typical of unexposed individuals are determined by using square-wave anodic stripping voltammetry at a disposable 287-element (15-35-microns diameter) carbon microarray electrode. Analysis of a series of low Pb-containing samples (blood [Pb] = 17 to 92 micrograms/L) by standard addition gives good accuracy (average bias vs graphite furnace atomic absorption spectroscopy = -4 micrograms/L) and precision (pooled SD = 7 micrograms/L). The signal/noise ratio is improved by about an order of magnitude over that found at a single carbon disk (10 microns diameter), resulting in a detection limit (for the microarray) of 5 micrograms/L for a 60-s deposition of sample.

Carbon↗

PubMed1994

Determination of lead in blood by square wave anodic stripping voltammetry at a carbon disk ultramicroelectrode.

A method for blood lead ([Pb]) analysis is developed based on square wave anodic stripping voltammetry (SWASV) in an Hg(2+)-containing solution using a 10-microns-diameter carbon disk ultramicroelectrode. SWASV eliminates interference from O2 in unsparged blood-derived sample solutions, and filtration of acidified samples through nitrocellulose reduces the concentration of interfering substances, increasing the size and improving the uniformity of peak currents. Blood [Pb] values obtained by SWASV are compared with blood [Pb] values determined by graphite furnace atomic absorption spectrophotometry; good accuracy and reasonable coefficients of variation in the range 10.6-20% (average of 13.5%) are found for blood [Pb] ranging from 4 to 30 micrograms/dL. Preliminary experiments using a carbon disk microarray electrode suggest future improvements in sensitivity.

Electrochemistry↗

PubMed1994

Factors influencing bone lead concentration in a suburban community assessed by noninvasive K x-ray fluorescence.

OBJECTIVE: To determine the influence of demographic, exposure and medical factors on the bone lead concentration of subjects with background (nonindustrial) environmental lead exposure. DESIGN: Survey. SETTING: Suburban residential community. PARTICIPANTS: A total of 101 subjects (49 males, 52 females; aged 11 to 78 years) were recruited from 49 of 123 households geographically located in a suburban residential neighborhood unexposed to any major source of industrial lead emissions. MAIN OUTCOME MEASUREMENTS: Cortical bone lead concentrations in the midshaft of the tibia were noninvasively measured by in vivo K x-ray fluorescence. Blood lead concentrations were measured by anodic stripping voltammetry. An administered questionnaire assessed potential sources of lead exposure and medical conditions affecting bone metabolism. RESULTS: After the exclusion of one outlier, log-transformed bone lead concentration was highly correlated with age (r = .71; P < or = .0001). Bone lead concentration showed no significant change up to age 20 years, increased with the same slope in men and women between ages 20 and 55 years, and then increased at a faster rate in men older than 55 years. In addition to the variables age and sex, the best fitting multiple regression model for bone lead concentration (R2 = .66; P < or = .0001) revealed a positive correlation with total pack-years of cigarette smoking and a negative correlation with a history of having nursed an infant for longer than 2 weeks. Blood lead concentrations of the subjects were low (geometric mean, 0.24 mumol/L [4.9 micrograms/dL]) and after log transformation were weakly correlated with log-transformed bone lead concentration (r = .23; P = .02). CONCLUSIONS: The age- and sex-related increases in bone lead concentration found by K x-ray fluorescence concur with published postmortem studies of bone lead concentration and are consistent with the kinetics of bone turnover and secular trends in lead exposure. These data help to establish a reference range for assessing the lead burden of other populations with environmental or occupational lead exposure.

Adolescent↗

PubMed1994

Formate in serum and urine after controlled methanol exposure at the threshold limit value.

Methanol will be present as a new air pollutant when methanol-powered vehicles are introduced in the United States. Little is known about the effect of low-dose methanol exposure. It is controversial whether or not formate, the main metabolite responsible for methanol's acute toxicity, is a sensitive biological marker of toxicity or exposure. We studied the effect of a 4-hr exposure at rest to 200 ppm of methanol vapors on endogenous serum formate and on urinary formic acid excretion. A randomized, double-blind study of human exposure to a constant concentration of methanol was performed in a whole-body exposure chamber. Twenty-six healthy volunteers, each serving as his or her own control, participated in sham and methanol exposures. Urine (at 0, 4, 8 hr) and serum specimens (15 time points over 8 hr) collected before, during, and after the exposure were measured for formate. We found no significant differences in serum formate concentration between exposure and control conditions either at any time point or for area under the curve. Mean concentrations at the end of the exposure were: exposed 14.28 +/- 8.90 mg/l and control 12.68 +/- 6.43 mg/l. A slight, but nonsignificant (p = 0.08), increase in urine formate excretion rate was found at 4 hr (exposed 2.17 +/- 1.69 mg/4 hr and control 1.67 +/- 1.02 mg/4 hr). Age, sex, folic acid level, and smoking were not significant covariates. At 200 ppm, methanol exposure does not contribute substantially to endogenous formate quantities. Serum and urine formate determinations are not sensitive biological markers of methanol exposure at the threshold limit value.

Absorption↗

PubMed1993

Effects of hyperparathyroidism on blood lead concentrations in man.

To investigate whether hyperparathyroidism has an effect on blood lead (Pb) concentrations and whether parathyroidectomy will alter blood Pb concentrations, we studied 15 subjects with primary hyperparathyroidism (HPTH) and 7 control subjects with thyroid nodules (TC). Blood Pb concentrations were determined several weeks prior to surgery and then again 4 months later. A reference group (REF) of nonsurgical lab/office workers was examined over the same periods of time. Initial mean blood Pb concentrations were 6.6 +/- 2.8, 6.0 +/- 2.9, and 5.0 +/- 1.7 micrograms/dl for the HPTH, TC, and REF groups (not significantly different), respectively. The mean percentage changes in blood Pb (before vs after) were -13.9, -4.9, and -6.1%. While the paired changes in blood Pb concentrations within the HPTH group were significant (P < 0.05), the percentage changes compared to either of the TC or REF groups were not significantly different. The percentage change in blood Pb correlated with the percentage change in serum calcium across all subjects (r = 0.5176, P = 0.0024, n = 24), although this correlation was not significant within any group alone. The HPTH group demonstrated expected changes in serum calcium, parathyroid hormone, and alkaline phosphatase concentrations. Three of the HPTH subjects received a CaNa2 EDTA chelation challenge (1 g intramuscularly) before and 4 months after surgery. Chelated amounts of Pb (microgram/24 hr before vs after) were 52 vs 38, 42 vs 47, and 60 vs 34. These data indicate that in the high bone turnover state of hyperparathyroidism that Pb concentrations in the blood-soft tissue compartment, and probably Pb mass, are not likely to be different from other individuals. Also parathyroidectomy results in a lowering of blood Pb concentrations possibly due to parallel movements of calcium.

Adult↗

PubMed1993

Urinary protein markers in pesticide applicators during a chlorinated hydrocarbon exposure.

A previous study of 16 pesticide applicators showed that N-acetylglucosaminidase (NAG) excretion during exposure to the soil nematocide, 1,3-dichloropropene (DCP), was correlated with DCP dose and the excretion of its major metabolite, N-acetyl-S-(cis-3-chloroprop-2-enyl)-cysteine (3CNAC). Using the same urine samples, two other proteins were measured: low concentrations of albumin ("microalbuminuria," ALB) and retinol-binding protein (RBP). For each worker there were five consecutive urine collection intervals (6-8 hr each): overnight prior to exposure, morning work shift, afternoon work shift, evening after work, and overnight. Paired comparisons of each interval to baseline (first interval) for each protein excretion (creatinine corrected) did not reveal significant increases. However, amounts of renal proteins per interval, in contrast to creatinine-corrected concentrations, were more strongly correlated with each other and with 3CNAC concentrations within samples. Clear dichotomous differences in urinary protein excretion were seen for high versus low exposure (< or > 1.5 mg 3CNAC excretion/day) for NAG and RBP, but not for ALB. Based on earlier findings of a slight elevation of NAG and the minimal changes reported herein for RBP, the possible effects of short-term workplace exposure to DCP on renal protein excretion appear to be mild.

Air Pollutants, Occupational↗

PubMed1992

Stable isotope labeling of lead compartments in rats with ultralow lead concentrations.

The role of the mammalian skeleton as an endogenous lead source is unclear. This is due in part to difficulties in distinguishing mobilized skeletal lead from other endogenous and exogenous lead sources. Therefore, we have applied ultraclean stable lead isotope techniques to label skeletal and soft tissue lead compartments within the rat with distinguishable lead isotopic signatures. Female Wistar (defined flora) rats were fed 206Pb-enriched drinking water ([Pb] = 110 ng/ml) and sacrificed after durations of 2, 4, 7, and 14 days. Blood, kidney, vertebra, and tibia tissues were analyzed for lead concentrations and stable isotopic compositions. The resulting isotopic ratios in soft (blood and kidney) and skeletal (vertebrae and tibia) tissues differed by approximately 40% after 2 days exposure to the 206Pb tracer. More than 90% of the tracer isotopic signature was contained in the soft tissues after 10 days exposure, while skeletal tissues acquired only approximately 50% of the tracer by the end of the study. Because these animals were maintained under trace metal-clean conditions, they contained lead concentrations in whole blood (0.3-3 ng/g), kidney (11-27 ng/g dry wt), and bone (35-70 ng/g dry wt) tissues that are the lowest known reported for contemporary terrestrial mammals, and they (in bone) are comparable to levels in preindustrial mammals. The elevated concentrations of lead in kidney (fresh weight) relative to levels in blood are consistent with the presence of specific lead-binding sites in the kidney at very low levels of exposure.

Animals↗

PubMed1991

Observations on the effect of parathyroid hormone on environmental blood lead concentrations in humans.

The effect of parathyroid hormone (PTH) on blood lead (Pb) concentrations was observed preliminarily in three different situations. Of 342 healthy bus drivers with no unusual exposure to Pb, 25 drivers with the highest and 25 with the lowest blood Pb were compared for serum PTH concentrations. There was no association between blood Pb and serum PTH concentrations. Eight women with postmenopausal osteoporosis enrolled in an experimental protocol to increase bone mass received daily PTH (1-34 fragment) for 1 week, calcitonin for the next 2 weeks, and oral calcium for the subsequent 10 weeks. This cycle was repeated four times during the year. Initial blood Pb concentrations averaged 6.0 micrograms/dl (range 2.1-8.9). Mean blood Pb concentrations decreased by 1.7 micrograms/dl over 1 year of therapy. The confidence interval for this change excluded zero, the mean change was significantly different from the mean change for comparative population (P less than 0.050), and paired changes were statistically significant (P = 0.045). Lastly, a single subject with hyperparathyroid disease and no unusual exposures to lead demonstrated stabilized blood Pb concentrations that were 50% lower after removal of his hyperplastic parathyroid glands. These observations suggest that the effect of PTH on increasing bone turnover and releasing Pb into blood is not easily detected at low physiologic amounts of PTH, but that with pathologic increases of PTH in hyperparathyroid disease, elevation of blood Pb from bone or increased gastrointestinal absorption may be possible. Likewise, either bone building therapies (PTH + calcitonin + calcium) may move Pb from blood into bone or supplemental calcium may decrease Pb gastrointestinal absorption, thereby explaining the observed lower blood Pb concentrations.

Adult↗

PubMed1991

Normal fetal outcome after maternal ciguateric toxin exposure in the second trimester.

A case of a severe episode of ciguatera poisoning in a mother during the second trimester is presented. The mother experienced an increase of fetal movements one hour after the poisonous meal. She endured multisystemic symptoms typical of ciguatera for eight weeks. The presence of ciguatoxin in the fish was confirmed by immunoassay and two bioassays. The newborn at term was normal with adequate respiratory and neurological reflexes. The child developed normally in his first 10 months. This is in contrast with another report of a mother exposed to ciguatoxin at term who delivered an infant suffering from facial palsy and possible myotonia of the hands. Dose and gestational timing may explain these observed differences.

Adult↗

PubMed1990

Influence of race, tobacco use, and caffeine use on the relation between blood pressure and blood lead concentration.

A number of studies have suggested a small to moderate positive relation between blood pressure and blood lead concentration in males (2-4 mmHg/In(microgram/dl]. However, this 1986 study of San Francisco bus drivers suggests larger relations in black males (n = 132) for both systolic pressure (7.5 mmHg/In(microgram/dl] and diastolic pressure (4.7 mmHg/In(microgram/dl] at very low blood lead concentrations (2-21 micrograms/dl). This increase appears to result from negative confounding, particularly after taking into account tobacco use. Relations are even larger in blacks who infrequently use caffeine (16.7 and 10.4 mmHg/In(microgram/dl) for systolic and diastolic pressure, respectively). In contrast, a negative relation between systolic pressure and blood lead concentration (-5.7 mmHg/In(microgram/dl] is suggested in nonblack males (n = 117). These findings indicate that race, lead accumulation, and physiologic effects related to caffeine use (e.g., catecholamine effects) may interact to produce marked differences in effect on blood pressure.

Black or African American↗

PubMed1990

Chemical dependency and drug testing in the workplace.

Urine testing for drug use in the workplace is now widespread, with the prevalence of positive drug tests in the work force being 0% to 15%. The prevalence of marijuana use is highest, and this can be reliably tested. Though it is prudent to rid the workplace of drug use, there is little scientific study on the relationship of drug use and workplace outcomes, such as productivity and safety. Probable-cause testing and preemployment testing are the most common applications. Random testing has been less accepted owing to its higher costs, unresolved legal issues, and predictably poor test reliability. Legal issues have focused on the right to policy, discrimination, and the lack of due process. The legal cornerstone of a good program is a policy that is planned and agreed on by both labor and management, which serves both as a contract and as a procedure in which expectations and consequences are known. The National Institute on Drug Abuse is certifying laboratories doing employee drug testing. Testing methods when done correctly are less prone to error than in the past, but screening tests can be defeated by adulterants. Although the incidence of false-positive results is low, such tests are less reliable when the prevalence of drug abuse is also low.

Civil Rights↗

PubMed1990

Utility and reliability of emergency toxicologic testing.

Emergency physicians using toxicologic testing should learn the capabilities of their laboratories: What is detectable? What is not? What is the expected turnaround time? Do pharmacologic relationships exist? In ordering test requests, the laboratory should allow the physician to order limited test combinations, and the physician can assist the laboratory in the search for unknowns by indicating the running diagnosis and suspected drugs. Only a few drugs require quantitation in serum in order to assist in therapeutic decisions. Urine drug screening is useful in documenting intoxications due to drugs and frequently demonstrates more drugs or drugs other than those clinically expected. The impact of findings from emergency drug screening upon diagnosis and therapy appears to be low. Although comprehensive drug screening in the emergency setting has a better positive predictive value ("rule-in") than negative predictive value, toxicologic screening may be useful as a "rule-out" test in other diagnostic applications of lower prior probability. Future directions in laboratory diagnosis of the intoxicated patient are likely to include growth in new immunoassays with limited applications, but with rapid turnaround within the Emergency Department. Also, with improvements in technology, screening of serum drugs will become more common, including the discovery of more quantitative relationships between serum concentration and toxic effects.

Ambulatory Care↗