Loss of social role awareness, a subdomain of social frailty, is an independent predictor of future adverse events in hospitalized older patients with heart failure

Background

Frailty is a complex syndrome characterized by a decline in functional reserve, and associated with aging and chronic diseases including heart failure (HF). The impact of physical frailty on prognosis and the effect of cardiac rehabilitation in HF patients have been well established. However, the data on the prognostic impact of social frailty (SF) in HF patients is limited.

Aims

We aimed to get new insight into mechanisms of the association of SF with clinical outcomes in older hospitalized HF patients.

Methods

A single-center, retrospective cohort study was conducted using data from 308 HF patients aged ≥65 years (mean age of 78±8 years; 49% females) who were admitted to our institute for the management of HF. SF was assessed using the validated Makizako's five questions. The following responses were considered positive for SF: (1) going out less frequently compared with last year; (2) not visiting friends; (3) not talking with someone every day; (4) not feeling helpful toward friends or family; and (5) living alone. SF was defined as two or more positive responses. The primary outcome was composite events defined by all-cause death and cardiovascular events. The missing data were imputed using multiple imputation by chained -equations algorithm.

Results

Of 308 older HF patients, 189 patients (61%) were SF. Patients with SF were significantly older, had lower body mass index, and a higher percentage of patients with physical frailty and cognitive frailty than those without SF. Seventy-five patients (24%) experienced composite events during a median follow-up period of 1.55-years (interquartile range, 0.88–2.20 years). Kaplan-Meier curves showed a significantly higher composite event rate in patients with SF than those without SF. In multivariate Cox regression analyses, SF was independently associated with a higher composite event rate after adjusting for pre-existing risk factors [adjusted hazard ratio (HR), 1.91; 95% confidence interval (CI), 1.09–3.35; p=0.03] (Figure 1A). In addition, further analyses showed that only the positive response on the question corresponding to the social role – not feeling helpful toward friends or family – among the questionnaire was an independent predictor for the incidence of the composite event (adjusted HR, 2.10; 95% CI, 1.29–3.41; p<0.01, Figure 1B). Inclusion of the response to the question regarding the social role into the baseline prognostic model improved the accuracy of prediction of the composite event (continuous net reclassification improvement, 0.46; 95% CI, 0.21–0.71; p<0.01; integrated discrimination improvement, 0.025; 95% CI 0.004–0.047; p=0.02; Figure 2).

Conclusion

Loss of social role awareness was associated with increased composite event risk and provided additive prognostic information in older HF patients, suggesting the importance of healthcare professionals' decision-making on the prevention and management of SF.

Funding Acknowledgement

Type of funding sources: None.

Coexistence of sarcopenia and osteoporosis in patients with heart failure: prevalence and association with functional status

Background

Sarcopenia, the loss of muscle mass and function, and osteoporosis, a condition of low bone mass and micro-architectural deterioration of bone, frequently coexist and are associated with low functional status in heart failure (HF) patients.

Aims

We aimed to investigate the impact of coexistence of sarcopenia and osteoporosis on functional status in HF patients.

Methods

This cross-sectional study was conducted using data from patients who admitted to our institute for the diagnosis and management of HF from 1 November 2015 to 30 April 2021. All patients received the dual-energy X-ray absorptiometry (DEXA) method before discharge. The diagnosis of sarcopenia was made according to the criteria of Asia Working Group for Sarcopenia 2019 recommendation as follows: reduced skeletal muscle mass [appendicular skeletal muscle mass index (ASMI) by DEXA, <7.00 kg/m2 in males and <5.40 kg/m2 in females] plus lower muscle strength (handgrip strength, <28 kg in males and <18 kg in females) and/or poor physical performance (gait speed, <1.0 m/s; chair stand test time. ≥12 s; short physical performance battery ≤9 points). In addition, bone mineral densities (BMDs) at the lumbar spine, femoral neck, and total femur were measured by DEXA, and osteoporosis was diagnosed when BMDs at any of the three sites were less than 70% of Young Adult Mean (YAM). Functional status was assessed by the Barthel Index (BI) within three days before discharge, and patients with a BI score of <85 points was defined as having functional dependence (FD). The missing data were imputed using multiple imputation by chained -equations algorithm.

Results

Four hundred-thirty eight patients [median age of 74 years (interquartile range, 65–82 years), 37% females] were included in the analyses. Of these, percentage of HF patients with sarcopenia, osteoporosis, and sarcopenia and osteoporosis was 45%, 34%, and 20%, respectively (Figure 1A). The analysis of covariance showed a lower %YAM at any sites in patients with sarcopenia than those without sarcopenia (Figure 1B). When patients were divided into subgroups according to the presence or absence of sarcopenia and osteoporosis, the prevalence of FD was 32%, 34%, and 48% in patients with osteoporosis alone, sarcopenia alone, and sarcopenia and osteoporosis, respectively. Multivariate logistic regression analysis indicated that an increase in adjusted odds ratio (OR) for predicting FD was observed across subgroups in the following order: patients with osteoporosis alone [OR, 1.64; 95% confidence interval (CI), 0.63–4.24; p=0.31], those with sarcopenia alone (OR, 2.44; 95% CI, 1.13–5.25; p=0.02) and those with both conditions (OR, 3.34; 95% CI, 1.52–7.38; p<0.01) (Figure 2).

Conclusion

There was considerable overlap between sarcopenia and osteoporosis in HF patients, which appeared to be a risk factor for FD.

Funding Acknowledgement

Type of funding sources: None.

Does serum 25-hydroxyvitamin D levels have impacts on sarcopenia in patients with chronic heart failure?

Funding Acknowledgements

Type of funding sources: None.

Introduction

Sarcopenia is associated with poor functional status and clinical outcomes in heart failure (HF) patients. Although recent observational studies showed the relationship between lower serum vitamin D levels and the development of poor physical function in community-dwelling older adults, involvement of vitamin D status in the development of sarcopenia in HF patients remain unclear. This study aimed to investigate the impact of serum vitamin D concentrations on sarcopenia in patients with HF.

Methods

We retrospectively enrolled 269 consecutive patients [median age of 73 years (interquartile range 63-82 years); 35% female] admitted to our institute for diagnosis and management of HF, and received the dual-energy X-ray absorptiometry (DEXA) method during the period from 1 September 2018 to 30 September 2021. The 25-hydroxyvitamin D [25(OH)D] was detected by a chemiluminescence immunoassay (CLIA) technology. The diagnosis of sarcopenia was made according to the criteria of Asia Working Group for Sarcopenia incorporating reduced skeletal muscle mass (appendicular skeletal muscle index [ASMI], <7.00 kg/m2 in males and <5.40 kg/m2 in females), and lower muscle strength (handgrip strength, <28 kg in males and <18 kg in females) and/or poor physical performance (gait speed, <1.0 m/s; chair stand test time, ≥12 s; short physical performance battery, ≤9 points).

Results

Of 269 patients, 116 (43%) patients had sarcopenia. An adjusted logistic regression model with a restricted cubic spline function showed that the odds ratio (OR) for sarcopenia increased as the serum 25(OH)D levels decreased. When the value that corresponded to an upper limit of 95% confidence interval (CI) for an OR of 1.0 was defined as the cut-off value of 25(OH)D levels for predicting sarcopenia, it was 18 ng/mL (Figure 1A). A multivariate logistic regression model was fit to calculate the propensity score (PS) for the 25(OH)D levels being <18 ng/mL based on covariates such as age, sex, and N-terminal pro B-type natriuretic peptide. (C-statistics 0.761). The inverse probability of treatment weighting (IPTW) was computed using PS to minimize differences in potential confounding factors between patients with a low serum 25(OH)D levels (<18 ng/mL) and those with a high serum 25(OH)D levels (≥18 ng/mL, Figure 1B). Results of the multivariate logistic regression analysis in the IPTW-weighted patients showed that a low serum 25(OH)D was independently associated with presence of sarcopenia (adjusted OR 2.03, 95% CI 1.31-3.16, p<0.01). In addition, patients with a low serum 25(OH)D had a significantly lower muscle strength and poor physical performance, but not ASMI, than those with a high serum 25(OH)D (Figure 2).

Conclusion

Decreased serum 25(OH)D levels are associated with decline in muscle strength and physical performance in HF patients. Serum 25(OH)D levels of <18 ng/mL may be a novel risk factor of sarcopenia in HF patients.

Novel equation for skeletal muscle mass estimation is useful for predicting mortality in patients with heart failure

Funding Acknowledgements

Type of funding sources: None.

Background

Skeletal muscle mass in heart failure (HF) patients is closely related to exercise tolerance and prognosis. Although the dual-energy X-ray absorptiometry (DEXA) method is a standard method for measuring skeletal muscle mass, it is not suitable in a daily clinical setting since it is a costly and hospital-based modality. We recently reported that an equation for appendicular skeletal muscle mass index (ASMI) estimation using anthropometric parameters predicted DEXA-measured ASMI in HF patients with reasonable accuracy. Here, we examined the prognostic impacts of ASMI predicted by the equation (predicted ASMI) in HF patients.

Methods

Data for 539 patients with HF ( 73 ± 14 years old, 43% female) who received the DEXA method and measurements of calf circumference (CC) and mid-arm circumference (MAC) between August 1, 2015, to August 31, 2020, were used for analyses. DEXA measured-appendicular skeletal muscle (ASM) was calculated as the sum of bone-free lean masses in the arms and legs, and ASMI was defined as ASM/height². Predicted ASMI was calculated as we previously reported: predicted ASMI (kg/m²) = [0.214 × weight (kg) + 0.217 × CC (cm) - 0.189 × MAC (cm) + 1.098 (male = 1, female = -1) + 0.576]/height² (m²). Low ASMI was defined as <7.0 kg/m² in males and <5.4 kg/m² in females, respectively. The primary endpoint was all-cause death. Multiple imputation using chained equations was used for the substitution of missing values.

Results

The median follow-up period was 1.75 years (interquartile range, 0.96 to 2.37 years), and 73 patients (15%) has died. Kaplan-Meier survival curves showed that patients with low DEXA measured-ASMI and patients with low predicted ASMI had significantly lower survival rates than those with high ASMI (Figure 1). In a multivariate Cox proportional hazard analyses adjusted for age, sex, logarithmic B-type natriuretic peptide, cystatin C based-estimated glomerular filtration rate, and gait speed, DEXA-measured ASMI [hazard ratio (HR), 0.982; 95% confidence interval (CI), 0.967 to 0.988; p<0.001] and predicted ASMI (HR, 0.979; 95% CI, 0.962 to 0.996; p=0.018) were independent predictors of all-cause mortality, respectively. Inclusion of predicted ASMI into the adjustment model improved the accuracy of prediction of the mortality after discharge [continuous net reclassification improvement, 0.338, p<0.01; integrated discrimination improvement, 0.020, p < 0.05] (Figure 2).

Conclusions

ASMI estimated by an equation using CC and MAC predicted the prognosis of HF patients at a similar level of accuracy to DEXA-measured ASMI, and it can be applied to the assessment of skeletal muscle mass in a daily clinical setting and in large population-based studies.

Barthel Index score predicts mortality in elderly heart failure: a goal of comprehensive cardiac rehabilitation

Background

Accurate prediction of mortality in heart failure (HF) patients is crucial for decision-making regarding HF therapies, but a strategy for the prediction of mortality in elderly HF patients has not been established. In addition, although favorable effects of comprehensive cardiac rehabilitation (CR) on clinical outcomes and functional status in HF patients have been demonstrated, a goal of comprehensive CR during hospitalization for reducing mortality remains unclear.

Aims

We examined whether assessment of basic activities of daily living (ADL) by the Barthel Index (BI), the most widely used tool for assessment of basic ADL, is useful for predicting all-cause mortality in elderly HF patients who received comprehensive CR.

Methods

This study was a single-center, retrospective and observational study. We retrospectively examined 413 HF patients aged ≥65 years (mean age, 78±7 years; 50% female) who were admitted to our institute for management of HF and received comprehensive CR during hospitalization. Functional status for performing basic ADL ability was assessed by the BI within 3 days before discharge. The clinical endpoint was all-cause death during the follow-up period.

Results

Of 413 HF patients, 116 patients (28%) died during a follow-up period of median 1.90-years (interquartile range, 1.20–3.23 years). Results of an adjusted dose-dependent association analysis showed that the hazard ratio (HR) of mortality increases in an almost linear fashion as the BI score decreases and that the BI score corresponding the hazard ratio of 1.0 is 85 (Figure A). To minimize the differences in potential confounding factors between patient with low BI (<85) and patients with high BI (≥85), inverse probability treatment weighting (IPTW) was calculated using propensity score. Kaplan-Meier survival curves, in which selection bias was minimized by use of IPTW for confounders, showed that patients with low BI (<85) had a higher mortality rate than did patients with high BI (≥85) (Figure B). In multivariate Cox regression analyses, low BI was independently associated with higher mortality after adjustment for predictors including brain natriuretic peptide and prior HF hospitalization (IPTW-adjusted HR, 1.75 [95% confidence interval, 1.03–2.98], p<0.001). Inclusion of the BI into the adjustment model improved the accuracy of prediction of mortality (continuous net reclassification improvement, 0.292, p=0.008; integrated discrimination improvement, 0.017, p=0.022).

Conclusion

A BI score of <85 at the time of discharge is associated with increased mortality independently of known prognostic markers, and achievement of functional status of a BI score ≥85 by comprehensive CR during hospitalization may contribute to a favorable outcome in elderly HF patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): the Japan Society for the Promotion of Science

Does preoperative oral clonidine inhibit salivary secretion during general anesthesia?

Clonidine is known to inhibit salivary secretions and cause dryness of the mouth. We evaluated the effect of preoperative oral clonidine on salivary secretions before and during general anesthesia. Twenty-eight adult patients, equally divided into four groups, received the following premedication 2 hr prior to induction of anesthesia. Group 1 patients received oral ranitidine 5 mg.kg(-1) alone. Groups 2 and 3 patients received oral clonidine 1 microg.kg(-1) and 3 microg.kg(-1) respectively with oral ranitidine 5 mg.kg(-1). Group 4 patients received no premedication and served as control. The volume of salivary secretions was determined by calculating the change in weight of four cotton wool cylinders placed in the oral space 10 min before and 30, 60 and 120 min after induction of anesthesia. Salivary volume was significantly less in the clonidine treatment groups before induction of anesthesia. After induction of anesthesia, there were no significant differences in salivary secretions among the four groups. No severe hypotension or bradycardia was seen in any patient of four groups. Preoperative oral ranitidine 5 mg.kg(-1) had no effect on salivary secretion. In conclusion, clonidine did not decrease salivary secretions further over the already decreased level during general anesthesia.

[A psychological burden on patients with clinical trials during anesthesia]

We investigated with questionnaires, psychological outline of 30 patients, who were requested to participate in clinical trials of anti-tachycardia drugs during anesthesia. Although 14 patients consented to the trial, the consent was not based on adequate understanding or volunteerism in 3 patients. Nine patients of the consented group were anxious about the possible use of the trial drug. Eight patients of the rejected group felt anxiety on surgery and anesthesia, which was the most common reason for rejection. Forty % of refused patients felt a guilty conscience or embarrassed. Although we tried to obtain patients' consent following governmental and institutional regulations and guidelines, not only the consented but also the refused patients suffer from psychological burden with the clinical trial. It is of concern that recruitment to the trial enhances anxiety of the patients as they already feel uneasiness, unrest, and insecurity facing anesthesia and surgery. To avoid entry of less informed or unwilling patients to the clinical trial, we must secure patients' veto, and recruitment should be performed by clinicians who are not involved in anesthesia practice.

Changes in the regulation of 5-hydroxytryptamine release by alpha2-adrenoceptors in the rat hippocampus after long-term desipramine treatment

In vivo microdialysis was used to measure the effects of long-term treatment of rats with desipramine upon the regulation by alpha2-adrenoceptors of serotonin (5-hydroxytryptamine, 5-HT) release from the serotonergic neurons in the hippocampus. Rats were injected with saline or desipramine, 10 mg/kg, i.p., every 12 h for 14 days. When added to the perfusion solution, brimonidine, an alpha2-adrenoceptor agonist, significantly inhibited the K+-evoked release of 5-HT in the hippocampi of saline-treated, control rats. This action of brimonidine was prevented by pretreating the rats with idazoxan, an alpha2-adrenoceptor antagonist. Long-term desipramine treatment significantly reduced the inhibitory effect of brimonidine upon the K+-evoked 5-HT release. With long-term administration of desipramine, noradrenaline content in the hippocampi was significantly decreased as compared with that of the control rats, whereas the basal noradrenaline concentration in the dialysate was significantly increased. On the other hand, both the 5-HT content of the hippocampus and the basal 5-HT concentration in the dialysate were significantly increased. The present study suggests that long-term administration of desipramine causes a functional subsensitivity of the presynaptic alpha2-adrenoceptors that regulate serotonergic neuronal function in the rat hippocampus. It also supports the concept that changes in the sensitivity of alpha2-adrenoceptors that regulate neurotransmitter release play an important role in the mechanism of antidepressant drug action.

Nucleotide sequence of the gene for a thermostable esterase from Pseudomonas putida MR-2068

The esterase gene (est) of Pseudomonas putida MR-2068 was cloned into Escherichia coli JM109. An 8-kb inserted DNA directed synthesis of an esterase in E. coli. The esterase gene was in a 1.1-kb PstI-ClaI fragment within the insert DNA. The complete nucleotides of the DNA fragment containing the esterase gene were sequenced and found to include a single open reading frame of 828 bp coding for a protein of 276 amino acid residues. The open reading frame was confirmed by N-terminal amino acid sequence analysis of the purified esterase. A potential Shine-Dalgarno sequence is followed by the open reading frame. The esterase activity of the recombinant E. coli was more than 200 times higher than that of parental strain, P. putida MR-2068.

Pharmacological characterization of alpha 2-adrenoceptor regulated serotonin release in the rat hippocampus

The purpose of the present study was to confirm the functional regulation by alpha 2-adrenoceptors of the release of serotonin (5-HT) from the rat hippocampus in vivo. Under several pharmacological conditions, extracellular levels of 5-HT were estimated by assaying its concentrations in the perfusate by high performance liquid chromatography with electrochemical detection. Extracellular 5-HT in the hippocampus was reduced by tetrodotoxin (10 microM) co-perfusion, but increased by perfusion of a selective 5-HT re-uptake inhibitor, fluoxetine (10 microM). Addition of potassium (K+, 120 mM) to the perfusion fluid evoked an approximately 3-fold increase in 5-HT release. When the alpha 2-adrenoceptor agonist UK14,304 (0.1-10 microM) was added to the perfusion solution, the K(+)-evoked 5-HT release was significantly inhibited in a concentration-dependent manner. This inhibitory action of UK14,304 was reversed by pretreatment with an alpha 2-adrenoceptor antagonist, idazoxan (5 mg/kg, i.p.). In rats which were catecholaminergically denervated with 6-hydroxydopamine, UK14,304 (10 microM) still inhibited the K(+)-evoked 5-HT release. Treatment with pertussis toxin (PTX) did not alter the K(+)-evoked release of 5-HT but abolished the inhibitory effect of UK14,304. These findings suggest that 5-HT release is functionally modulated via alpha 2-adrenoceptors located on the serotonergic nerve terminals in the rat hippocampus and furthermore, the possibility that the inhibitory of alpha 2-adrenoceptors is linked to G-proteins which are substrates of PTX.

Cloning and expression of Pseudomonas putida esterase gene in Escherichia coli and its use in enzymatic production of D-beta-acetylthioisobutyric acid

The esterase catalyzes the stereoselective hydrolysis of methyl DL-beta-acetylthioisobutyrate (DL-ester) to give D-beta-acetylthioisobutyric acid (DAT). To use the enzyme for DAT production, the esterase gene of Pseudomonas putida was cloned and expressed in E. coli. The recombinant E. coli containing the esterase gene produced a large amount of the enzyme in an active form. This strain could be used for the asymmetric synthesis of DAT.

[Pharmacological characterization of alpha 2-adrenoceptor regulated 5-HT release in the rat hippocampus]

The purpose of the present study is to confirm the functional regulation of alpha 2-adrenoceptor on the release of serotonin (5-HT) from the rat hippocampus in vivo. Under several pharmacological conditions, extracellular levels of 5-HT were estimated by assaying its concentrations in the perfusion fluid through the use of high-performance liquid chromatography with electrochemical detection. Extracellular 5-HT in the hippocampus was reduced by tetrodotoxin, 10 microM co-perfusion and was increased by perfusion with a selective 5-HT reuptake inhibitor, fluoxetine, 10 microM. Addition of potassium (K+; 120 mM) to the perfusion fluid evoked an approximately 3-fold increase in 5-HT release, and a calcium free medium completely prevented this K(+)-evoked 5-HT release. Potassium-evoked 5-HT release from the hippocampus of freely moving rats was significantly and concentration-dependently inhibited when alpha 2-adrenoceptor agonist, UK14,304, 0.1 microM to 10 microM was added to the perfusion solution, while the output of a 5-HT major metabolite, 5-hydroxyindoleacetic acid (5-HIAA), remained unchanged. This action of UK14,304 was prevented by pretreatment with idazoxan, 5 mg/kg, i. p., an alpha 2-adrenoceptor antagonist. In rats that were catecholaminergically denervated with 6-hydroxydopamine, UK14,304, 10 microM also inhibited the potassium-evoked 5-HT release, but had no effect on the 5-HIAA output. The UK14,304-induced inhibition of 5-HT release was prevented by pretreatment with pertussis toxin (PTX). These findings suggest that 5-HT release is functionally modulated via alpha 2-adrenoceptors located on the serotonergic nerve terminals in the rat hippocampus. They also indicate the possibility that the inhibition of 5-HT release via alpha 2-adrenoceptors is linked to G-proteins which are substrates of PTX.

[Pneumonia due to aspiration of povidone-iodine during anesthesia--a case report]

We report a case of pneumonia secondary to aspiration of povidone-iodine, which was used as an oral antiseptic. The patient was 17 y.o. female (body weight: 70 kg) who underwent a transsphenoidal resection of pituitary adenoma. Although she had a history of asthma during her childhood, no asthmatic attacks occurred for the past 10 yrs. After satisfactory anesthesia induction and tracheal intubation, 60 ml of 0.7% povidone-iodine solution was used to clean the oral cavity by a surgeon. Insufficient sealing by the cuff occurred after suturing the tube, which had made a needle hole in the cuff. Arterial oxygen saturation dropped to 90% and an increased resistance in the lungs was noted. The trachea was reintubated and she was transferred to the ICU. Her chest X-ray revealed signs of pneumonia and atelectasis in the right upper lobe. Mechanical ventilation with PEEP and periodical bronchial toilet were performed during her stay in the ICU for 42 hrs. A week was needed for the improvement of her X-ray findings. Although povidone-iodine is thought to be safe and affective antiseptics, severe complications from its aspiration may occur in patients whose airways are sensitive as observed in this case.

Effect of preanesthetic intramuscular ranitidine on gastric acidity and volume in children

STUDY OBJECTIVE

To evaluate the effects of preanesthetic administration of intramuscular (IM) ranitidine on pH and volume of gastric contents in children.

DESIGN

Three randomized treatment groups.

SETTING

Central operating rooms at a university hospital.

PATIENTS

Forty children age 1 to 10 years undergoing a variety of elective surgical procedures requiring general anesthesia with endotracheal intubation.

INTERVENTIONS

IM ranitidine 1 mg/kg (n = 15) or 2 mg/kg (n = 15) was administered 2 hours prior to induction of anesthesia. Ten patients without ranitidine served as the control group. An orogastric tube was inserted into each patient.

MEASUREMENTS AND MAIN RESULTS

Gastric fluid pH and volume were measured every hour in the three groups. Plasma ranitidine concentrations were measured in ten patients of the ranitidine-treated groups. The mean volume of gastric fluid at induction of anesthesia was significantly lower in the ranitidine-treated patients (2.4 ml for ranitidine 1 mg/kg, 3.2 ml for ranitidine 2 mg/kg) than in the controls (8.6 ml; p less than 0.05). The mean pH values at induction of anesthesia were significantly higher in the ranitidine-treated patients (4.6 for 1 mg/kg, 6.7 for 2 mg/kg) than in the controls (2.1; p less than 0.05). Dose-dependent plasma ranitidine concentrations were obtained.

CONCLUSIONS

Preanesthetic IM ranitidine 1 to 2 mg/kg resulted in a higher pH and lower volume of gastric fluid at the time of induction and in a higher pH during 3 hours of anesthesia. This therapy may be a useful adjunct to premedication for children who have a greater than normal risk of pulmonary aspiration during anesthesia.

[The effect of dopamine or dobutamine on plasma concentration of magnesium in dogs]

Plasma magnesium (Mg) concentration of dogs was determined with atomic absorption spectrophotometry during the infusion of dopamine (DOA) or dobutamine (DOB). Other electrolytes were also measured with same samples. Normoventilation was maintained during this experiment in order to avoid the respiratory interference. DOA 15-20 micrograms.kg-1.min-1 decreased Mg concentration significantly. DOB 5-20 micrograms.kg-1.min-1 did not change Mg concentration. Potassium (K) values were almost constant during infusion of both drugs, but DOB reduced K concentration at the dose of 20 micrograms.kg-1.min-1. Ionized calcium ion tended to decrease in DOA and to increase in DOB while the dose of the catecholamines was increased. These were not significant changes. These changes of concentration returned to control values 1 hour after stopping drug administrations. We speculate that beta-receptor, especially beta 2-receptor stimulation by DOA is responsible for the decrease of Mg in the mechanism of Mg uptake into cells of such tissues as liver or muscle.