Insulin does not stimulate ß-alanine transport into human skeletal muscle.

To test whether high circulating insulin concentrations influence the transport of ß-alanine into skeletal muscle at either saturating or subsaturating ß-alanine concentrations, we conducted two experiments whereby ß-alanine and insulin concentrations were controlled. In experiment 1, 12 men received supraphysiological amounts of ß-alanine intravenously (0.11 g·kg-1·min-1 for 150 min), with or without insulin infusion. ß-Alanine and carnosine were measured in muscle before and 30 min after infusion. Blood samples were taken throughout the infusion protocol for plasma insulin and ß-alanine analyses. ß-Alanine content in 24-h urine was assessed. In experiment 2, six men ingested typical doses of ß-alanine (10 mg/kg) before insulin infusion or no infusion. ß-Alanine was assessed in muscle before and 120 min following ingestion. In experiment 1, no differences between conditions were shown for plasma ß-alanine, muscle ß-alanine, muscle carnosine and urinary ß-alanine concentrations (all P > 0.05). In experiment 2, no differences between conditions were shown for plasma ß-alanine or muscle ß-alanine concentrations (all P > 0.05). Hyperinsulinemia did not increase ß-alanine uptake by skeletal muscle cells, neither when substrate concentrations exceed the Vmax of ß-alanine transporter TauT nor when it was below saturation. These results suggest that increasing insulin concentration is not necessary to maximize ß-alanine transport into muscle following ß-alanine intake.

24-Week ß-alanine ingestion does not affect muscle taurine or clinical blood parameters in healthy males.

PURPOSE: To investigate the effects of chronic beta-alanine (BA) supplementation on muscle taurine content, blood clinical markers and sensory side-effects. METHODS: Twenty-five healthy male participants (age 27 ± 4 years, height 1.75 ± 0.09 m, body mass 78.9 ± 11.7 kg) were supplemented with 6.4 g day-1 of sustained-release BA (N = 16; CarnoSyn™, NAI, USA) or placebo (PL; N = 9; maltodextrin) for 24 weeks. Resting muscle biopsies of the m. vastus lateralis were taken at 0, 12 and 24 weeks and analysed for taurine content (BA, N = 12; PL, N = 6) using high-performance liquid chromatography. Resting venous blood samples were taken every 4 weeks and analysed for markers of renal, hepatic and muscle function (BA, N = 15; PL, N = 8; aspartate transaminase; alanine aminotransferase; alkaline phosphatase; lactate dehydrogenase; albumin; globulin; creatinine; estimated glomerular filtration rate and creatine kinase). RESULTS: There was a significant main effect of group (p = 0.04) on muscle taurine, with overall lower values in PL, although there was no main effect of time or interaction effect (both p > 0.05) and no differences between specific timepoints (week 0, BA: 33.67 ± 8.18 mmol kg-1 dm, PL: 27.75 ± 4.86 mmol kg-1 dm; week 12, BA: 35.93 ± 8.79 mmol kg-1 dm, PL: 27.67 ± 4.75 mmol kg-1 dm; week 24, BA: 35.42 ± 6.16 mmol kg-1 dm, PL: 31.99 ± 5.60 mmol kg-1 dm). There was no effect of treatment, time or any interaction effects on any blood marker (all p > 0.05) and no self-reported side-effects in these participants throughout the study. CONCLUSIONS: The current study showed that 24 weeks of BA supplementation at 6.4 g day-1 did not significantly affect muscle taurine content, clinical markers of renal, hepatic and muscle function, nor did it result in chronic sensory side-effects, in healthy individuals. Since athletes are likely to engage in chronic supplementation, these data provide important evidence to suggest that supplementation with BA at these doses for up to 24 weeks is safe for healthy individuals.

Comparison of Two ß-Alanine Dosing Protocols on Muscle Carnosine Elevations.

OBJECTIVE: ß-alanine (BA) is a nonproteogenic amino acid that combines with histidine to form carnosine. The amount taken orally in individual doses, however, is limited due to symptoms of paresthesia that are associated with higher doses. The use of a sustained-release formulation has been reported to reduce the symptoms of paresthesia, suggesting that a greater daily dose may be possible. The purpose of the present study was to determine whether increasing the daily dose of BA can result in a similar increase in muscle carnosine in a reduced time. METHODS: Eighteen men and twelve women were randomized into either a placebo (PLC), 6-g BA (6G), or 12-g BA (12G) groups. PLC and 6G were supplemented for 4 weeks, while 12G was supplemented for 2 weeks. A resting blood draw and muscle biopsy were obtained prior to (PRE) and following (POST) supplementation. Plasma and muscle metabolites were measured by high-performance liquid chromatography. The loss in peak torque (ΔPT) was calculated from maximal isometric contractions before and after 250 isokinetic kicks at 180°·sec-1 PRE and POST. RESULTS: Both 12G (p = 0.026) and 6G (p = 0.004) increased muscle carnosine compared to PLC. Plasma histidine was decreased from PRE to POST in 12G compared to PLC (p = 0.002) and 6G (p = 0.001), but no group x time interaction (p = 0.662) was observed for muscle histidine. No differences were observed for any hematological measure (e.g., complete blood counts) or in symptoms of paresthesia among the groups. Although no interaction was noted in ΔPT, a trend (p = 0.073) was observed. CONCLUSION: Results of this investigation indicate that a BA supplementation protocol of 12 g/d-1, using a sustained-release formulation, can accelerate the increase in carnosine content in skeletal muscle while attenuating paresthesia.

Accumulation of alpha-fluoro-beta-alanine and fluoro mono acetate in a patient with 5-fluorouracil-associated hyperammonemia.

PURPOSE: High-dose 5-fluorouracil (5-FU) containing chemotherapy occasionally causes hyperammonemia and can be lethal. However, the mechanism of 5FU-associated hyperammonemia has not been known. The aim of this study was to reveal the pharmacokinetics of 5-FU-associated hyperammonemia in a recurrent colorectal cancer patient with end-stage renal disease (ESRD). METHODS: We experienced a case of hyperammonemia during mFOLFOX6 plus bevacizumab therapy for recurrent colorectal cancer. He was a dialyzed patient due to diabetic nephropathy and was registered to prospective blood sampling for pharmacokinetics analysis during chemotherapy. Blood concentrations of 5-FU and its catabolites were determined by inductively coupled plasma-mass spectrometry. RESULTS: The patient developed hyperammonemia encephalopathy 41 h after the initiation of continuous 5-FU infusion (on the third day). Before onset of hyperammonemia encephalopathy, serum alpha-fluoro-beta-alanine (FBAL, 59.2 µg/ml) and fluoro mono acetate (FMA, 905.8 ng/ml) were gradually increased. After hemodialysis for hyperammonemia, FBAL and FMA were collaterally decreased and his symptom was improved. Other intermediate catabolites of 5-FU, dihydrofluorouracil, and alpha-fluoro-beta-ureidopropionic acid were not changed. CONCLUSION: We found increases of serum FBAL and FMA under the condition of hyperammonemia in the patient with ESRD during mFOLFOX6 plus bevacizumab therapy. This research supported the hypothesis that impairment of tricarboxylic acid (TCA) cycle by FMA would cause 5-FU-associated hyperammonemia.

Effects of Histidine and ß-alanine Supplementation on Human Muscle Carnosine Storage.

PURPOSE: Carnosine is a dipeptide composed of ß-alanine and L-histidine and is present in skeletal muscle. Chronic oral ß-alanine supplementation can induce muscle carnosine loading and is therefore seen as the rate-limiting factor for carnosine synthesis. However, the effect of L-histidine supplementation on carnosine levels in humans is never established. This study aims to investigate whether 1) L-histidine supplementation can induce muscle carnosine loading and 2) combined supplementation of both amino acids is more efficient than ß-alanine supplementation alone. METHODS: Fifteen male and 15 female participants were equally divided in three groups. Each group was supplemented with either pure ß-alanine (BA) (6 g·d), L-histidine (HIS) (3.5 g·d), or both amino acids (BA + HIS). Before (D0), after 12 d (D12), and after 23 d (D23) of supplementation, carnosine content was evaluated in soleus and gastrocnemius medialis muscles by H-MRS, and venous blood samples were collected. Muscle biopsies were taken at D0 and D23 from the vastus lateralis. Plasma and muscle metabolites (ß-alanine, histidine, and carnosine) were measured by high-performance liquid chromatography. RESULTS: Both BA and BA + HIS groups showed increased carnosine concentrations in all investigated muscles, with no difference between these groups. By contrast, carnosine levels in the HIS group remained unaltered. Histidine levels were significantly decreased in plasma (-30.6%) and muscle (-31.6%) of the BA group, and this was prevented when ß-alanine and L-histidine were supplemented simultaneously. CONCLUSION: We confirm that ß-alanine, and not L-histidine, is the rate-limiting precursor for carnosine synthesis in human skeletal muscle. Yet, although L-histidine is not rate limiting, its availability is not unlimited and gradually declines upon chronic ß-alanine supplementation. The significance of this decline still needs to be determined, but may affect physiological processes such as protein synthesis.

Beta-alanine supplementation enhances judo-related performance in highly-trained athletes.

OBJECTIVES: In official judo competitions, athletes usually engage in 5-7 matches in the same day, performing numerous high-intensity efforts interspersed by short recovery intervals. Thus, glycolytic demand in judo is high and acidosis may limit performance. Carnosine is a relevant intracellular acid buffer whose content is increased with beta-alanine supplementation. Thus, we hypothesized that beta-alanine supplementation could attenuate acidosis and improve judo performance. DESIGN: Twenty-three highly-trained judo athletes were randomly assigned to receive either beta-alanine (6.4gday-1) or placebo (dextrose, same dosage) for 4 weeks. METHODS: Performance was assessed before (PRE) and after (POST) supplementation through a 5-min simulated fight (randori) followed by 3 bouts of the Special Judo Fitness Test (SJFT). Blood samples were collected for blood pH, bicarbonate (HCO3-) and lactate determination. RESULTS: Beta-alanine supplementation improved the number of throws per set and the total number of throws (both p<0.05). Placebo did not change these variables (both p>0.05). Blood pH and HCO3- reduced after exercise (all p<0.001), with no between-group differences (all p>0.05). However, the lactate response to exercise increased in the beta-alanine group as compared to placebo (p<0.05). CONCLUSIONS: In conclusion, 4 weeks of beta-alanine supplementation effectively enhance judo-related performance in highly-trained athletes.

Carnosine and anserine homeostasis in skeletal muscle and heart is controlled by ß-alanine transamination.

KEY POINTS: Using recombinant DNA technology, the present study provides the first strong and direct evidence indicating that ß-alanine is an efficient substrate for the mammalian transaminating enzymes 4-aminobutyrate-2-oxoglutarate transaminase and alanine-glyoxylate transaminase. The concentration of carnosine and anserine in murine skeletal and heart muscle depends on circulating availability of ß-alanine, which is in turn controlled by degradation of ß-alanine in liver and kidney. Chronic oral ß-alanine supplementation is a popular ergogenic strategy in sports because it can increase the intracellular carnosine concentration and subsequently improve the performance of high-intensity exercises. The present study can partly explain why the ß-alanine supplementation protocol is so inefficient, by demonstrating that exogenous ß-alanine can be effectively routed toward oxidation. ABSTRACT: The metabolic fate of orally ingested ß-alanine is largely unknown. Chronic ß-alanine supplementation is becoming increasingly popular for improving high-intensity exercise performance because it is the rate-limiting precursor of the dipeptide carnosine (ß-alanyl-l-histidine) in muscle. However, only a small fraction (3-6%) of the ingested ß-alanine is used for carnosine synthesis. Thus, the present study aimed to investigate the putative contribution of two ß-alanine transamination enzymes, namely 4-aminobutyrate-2-oxoglutarate transaminase (GABA-T) and alanine-glyoxylate transaminase (AGXT2), to the homeostasis of carnosine and its methylated analogue anserine. We found that, when transfected into HEK293T cells, recombinant mouse and human GABA-T and AGXT2 are able to transaminate ß-alanine efficiently. The reaction catalysed by GABA-T is inhibited by vigabatrin, whereas both GABA-T and AGXT2 activity is inhibited by aminooxyacetic acid (AOA). Both GABA-T and AGXT2 are highly expressed in the mouse liver and kidney and the administration of the inhibitors effectively reduced their enzyme activity in liver (GABA-T for vigabatrin; GABA-T and AGXT2 for AOA). In vivo, injection of AOA in C57BL/6 mice placed on ß-alanine (0.1% w/v in drinking water) for 2 weeks lead to a 3-fold increase in circulating ß-alanine levels and to significantly higher levels of carnosine and anserine in skeletal muscle and heart. By contrast, specific inhibition of GABA-T by vigabatrin did not affect carnosine and anserine levels in either tissue. Collectively, these data demonstrate that homeostasis of carnosine and anserine in mammalian skeletal muscle and heart is controlled by circulating ß-alanine levels, which are suppressed by hepatic and renal ß-alanine transamination upon oral ß-alanine intake.

Plasma carnosine, but not muscle carnosine, attenuates high-fat diet-induced metabolic stress.

There is growing in vivo evidence that the dipeptide carnosine has protective effects in metabolic diseases. A critical unanswered question is whether its site of action is tissues or plasma. This was investigated using oral carnosine versus ß-alanine supplementation in a high-fat diet rat model. Thirty-six male Sprague-Dawley rats received a control diet (CON), a high-fat diet (HF; 60% of energy from fat), the HF diet with 1.8% carnosine (HFcar), or the HF diet with 1% ß-alanine (HFba), as ß-alanine can increase muscle carnosine without increasing plasma carnosine. Insulin sensitivity, inflammatory signaling, and lipoxidative stress were determined in skeletal muscle and blood. In a pilot study, urine was collected. The 3 HF groups were significantly heavier than the CON group. Muscle carnosine concentrations increased equally in the HFcar and HFba groups, while elevated plasma carnosine levels and carnosine-4-hydroxy-2-nonenal adducts were detected only in the HFcar group. Elevated plasma and urine N(ε)-(carboxymethyl)lysine in HF rats was reduced by ∼50% in the HFcar group but not in the HFba group. Likewise, inducible nitric oxide synthase mRNA was decreased by 47% (p < 0.05) in the HFcar group, but not in the HFba group, compared with HF rats. We conclude that plasma carnosine, but not muscle carnosine, is involved in preventing early-stage lipoxidation in the circulation and inflammatory signaling in the muscle of rats.

The effect of ß-alanine and NaHCO3 co-ingestion on buffering capacity and exercise performance with high-intensity exercise in healthy males.

INTRODUCTION: ß-alanine (BAl) and NaHCO3 (SB) ingestion may provide performance benefits by enhancing concentrations of their respective physiochemical buffer counterparts, muscle carnosine and blood bicarbonate, counteracting acidosis during intense exercise. This study examined the effect of BAl and SB co-supplementation as an ergogenic strategy during high-intensity exercise. METHODS: Eight healthy males ingested either BAl (4.8 g day(-1) for 4 weeks, increased to 6.4 g day(-1) for 2 weeks) or placebo (Pl) (CaCO3) for 6 weeks, in a crossover design (6-week washout between supplements). After each chronic supplementation period participants performed two trials, each consisting of two intense exercise tests performed over consecutive days. Trials were separated by 1 week and consisted of a repeated sprint ability (RSA) test and cycling capacity test at 110 % Wmax (CCT110 %). Placebo (Pl) or SB (300 mg kgbw(-1)) was ingested prior to exercise in a crossover design to creating four supplement conditions (BAl-Pl, BAl-SB, Pl-Pl, Pl-SB). RESULTS: Carnosine increased in the gastrocnemius (n = 5) (p = 0.03) and soleus (n = 5) (p = 0.02) following BAl supplementation, and Pl-SB and BAl-SB ingestion elevated blood HCO3 (-) concentrations (p < 0.01). Although buffering capacity was elevated following both BAl and SB ingestion, performance improvement was only observed with BAl-Pl and BAl-SB increasing time to exhaustion of the CCT110 % test 14 and 16 %, respectively, compared to Pl-Pl (p < 0.01). CONCLUSION: Supplementation of BAl and SB elevated buffering potential by increasing muscle carnosine and blood bicarbonate levels, respectively. BAl ingestion improved performance during the CCT110 %, with no aggregating effect of SB supplementation (p > 0.05). Performance was not different between treatments during the RSA test.

Point-of-care coagulation testing for assessment of the pharmacodynamic anticoagulant effect of direct oral anticoagulant.

BACKGROUND: This investigation was carried out with already available point-of-care testing (POCT) systems for coagulation parameters to evaluate the qualitative and semiquantitative determination of the time- and concentration-dependent anticoagulant effects of the direct oral anticoagulants rivaroxaban and dabigatran. METHODS: The whole blood prothrombin time (PT), activated partial thromboplastin time (aPTT), and activated clotting time (ACT) were determined using the GEM PCL Plus coagulation system. Whole blood PT was also measured on the CoaguCheck XS instrument. In addition, PT and aPTT values were obtained in citrated plasma using the PT reagent Neoplastin Plus and the STA APTT reagent. Drug concentrations of rivaroxaban and dabigatran were determined with a chromogenic anti-Xa assay and the hemoclot assay, which are reported to have good agreement with liquid chromatography coupled with tandem mass spectrometry measurements. POCT was performed in 27 consecutive patients who received rivaroxaban 10, 15, or 20 mg once daily and in 15 patients receiving dabigatran 110 or 150 mg twice daily. Blood samples were collected predose and 2 hours after observed drug intake at steady state. RESULTS: Two hours after observed rivaroxaban administration, the whole blood PT measured on the GEM PCL Plus was prolonged by an average of 64.5% in comparison with predose levels. Less differentiation was observed for rivaroxaban when the PT was measured on the CoaguCheck XS instrument or in plasma (prolongation of 24.1% and 36.8%, respectively). After 2 hours observed dabigatran administration, the whole blood aPTT was comparable with plasma values and was prolonged by 23.5% in comparison with trough values. Significant concentration-dependent prolongations of the activated clotting time were observed to different extents for both direct anticoagulants. CONCLUSIONS: Direct oral anticoagulants display variable ex vivo effects on different POCT-assays. POCT for aPTT is sensitive to increased concentrations of dabigatran, whereas the PT-POCT assessed with test systems such as the GEM PCL Plus may be helpful to measure the pharmacodynamic anticoagulant effects of rivaroxaban in emergency clinical situations.

Measurement of dabigatran and rivaroxaban in primary prevention of venous thromboembolism in 106 patients, who have undergone major orthopedic surgery: an observational study.

No routine coagulation laboratory test is recommended during rivaroxaban or dabigatran treatment. However measuring drug concentration and/or anticoagulant activity can be desirable in some special clinical settings, such as bleeding, thrombosis recurrence or emergency surgery. The effects of dabigatran etexilate and rivaroxaban on various coagulation assays have been previously studied in normal plasma spiked with increasing concentrations of the drug. In contrast, few data are available in routinely treated patients. In order to perform and to interpret the results of these tests, it is necessary to determine the usual responses of patient's plasma. We have used several coagulation tests in a prospective study including 106 patients receiving thromboprophylactic treatment with dabigatran 150 or 220 mg od and rivaroxaban 10 mg od for major orthopaedic surgery. The most common tests--prothrombin time (PT) and activated partial thromboplastin time (aPTT)--give results, which vary according to the reagent used. To overcome this limitation, we advocate the use of plasma calibrators, which decreases the inter-laboratory heterogeneity of results. Anti-Xa measurement and Hemoclot, a thrombin diluted clotting assay, are specific assays which have been proposed for rivaroxaban and dabigatran respectively. These tests, conventional PT, aPTT and thrombin generation (TG) have been performed. We demonstrated that measurements of both drugs can determine reliably the drug concentration in patients' plasmas. PT is more prolonged with rivaroxaban than with dabigatran. Interestingly, the pattern of TG was clearly different in relation to the difference in the mechanism of action of the two new anticoagulants. A significant inter-individual variability of response is detected. Rivaroxaban--mean Cmax 140 ng/mL (extremes 0-412) induces a greater increase of PT than dabigatran. aPTT is sensitive to dabigatran. Rivaroxaban concentrations were in good agreement with two other studies while unexplained lower than expected concentrations were found in dabigatran patients receiving 220 mg once a day [mean Cmax 60 ng/mL (extremes 0-320)]. An interference by pantoprazole, a drug which reduces dabigatran absorption, could explain the observed lower than expected results.

Novel direct factor IIa and Xa inhibitors: mechanisms of action and preclinical studies.

The need to overcome certain limitations of the existing anticoagulant agents (heparin, LMWH and VKAs) and to achieve more convenient long-term anticoagulation has fueled the quest for the "ideal anticoagulant", an agent that would exert at least similar antithrombotic effects with a substantially improved pharmacologic profile and significantly less bleeding complications. The major disadvantages of the traditional agents were the narrow therapeutic window with serious drug and food interactions and the need for regular blood monitoring. Coagulation factors IIa and Xa have proved the most attractive pharmacologic targets due to their key role in the coagulation process and the opportunity of blocking thrombin generation before the level of thrombin production that results in amplification of the anticoagulant effect while preserving some of thrombin hemostatic effect. This review summarizes the mechanism of action of some of the most promising novel oral direct factor IIa and Xa inhibitors with a focus on published preclinical trials that led to their clinical development.

Low plasma carnosinase activity promotes carnosinemia after carnosine ingestion in humans.

A polymorphism in the carnosine dipeptidase-1 gene (CNDP1), resulting in decreased plasma carnosinase activity, is associated with a reduced risk for diabetic nephropathy. Because carnosine, a natural scavenger/suppressor of ROS, advanced glycation end products, and reactive aldehydes, is readily degraded in blood by the highly active carnosinase enzyme, it has been postulated that low serum carnosinase activity might be advantageous to reduce diabetic complications. The aim of this study was to examine whether low carnosinase activity promotes circulating carnosine levels after carnosine supplementation in humans. Blood and urine were sampled in 25 healthy subjects after acute supplementation with 60 mg/kg body wt carnosine. Precooled EDTA-containing tubes were used for blood withdrawal, and plasma samples were immediately deproteinized and analyzed for carnosine and ß-alanine by HPLC. CNDP1 genotype, baseline plasma carnosinase activity, and protein content were assessed. Upon carnosine ingestion, 8 of the 25 subjects (responders) displayed a measurable increase in plasma carnosine up to 1 h after supplementation. Subjects with no measurable increment in plasma carnosine (nonresponders) had ∼2-fold higher plasma carnosinase protein content and ∼1.5-fold higher activity compared with responders. Urinary carnosine recovery was 2.6-fold higher in responders versus nonresponders and was negatively dependent on both the activity and protein content of the plasma carnosinase enzyme. In conclusion, low plasma carnosinase activity promotes the presence of circulating carnosine upon an oral challenge. These data may further clarify the link among CNDP1 genotype, carnosinase, and diabetic nephropathy.

[Adjuvant treatment of patients with neoplastic lesions using the combination of a vitamin complex and an amino acid. Apropos of a series of 17 cases of epidermoid carcinoma of the upper aerodigestive tract]. / Traitement adjuvant de sujets atteints de lésions néoplasiques par l'association d'un complexe vitaminique et d'un acide aminé. A propos d'une série de 17 carcinomes épidermoïdes des voies aérodigestives supérieures.

The aim of the work reported here was to evaluate the effects of an adjuvant treatment composed of an association of vitamins with an amino acid: beta-alanine, in cancer patients. This adjuvant therapy has been given to 17 subjects with a squamous cell carcinoma of upper aerodigestive tract treated by radiotherapy most cases were T3 (according to the TNM-UICC). After a 63 months follow-up, 7 patients are alive and sterilized, 4 are alive but no sterilized, 2 died, 4 were excluded from the study. Besides a physical comfort improved in all our patients, we note a restoration of the immune defenses, both humoral and cellular, disturbed by radiotherapy. At last, we note an increase of survival in the patients treated by the adjuvant therapy, compared to a reference population of patients with squamous cell carcinoma of upper aerodigestive tract. Despite the limits of the study, it was interesting to report the positive effects of the therapeutical association, vitamins and beta-alanine, after a combined radio-surgical treatment of patients with squamous cell carcinoma of upper aerodigestive tract.

[Pharmacokinetic, bacteriological, and clinical studies on panipenem/betamipron in children].

Pharmacokinetic, bacteriological and clinical studies were performed on panipenem/betamipron (PAPM/BP) in children. The results are summarized as follow: 1. Twelve patients with various bacterial infectious diseases were treated with PAPM/BP. Each dose was 20 mg/20 mg/kg, administered 3 times daily, in 30-minute intravenous drip infusion. Treatments were continued for 5-22 days. Clinical efficacies of PAPM/BP in 12 patients with bacterial infections (1 with suspected sepsis, 5 with pneumonia, 1 with acute maxillary sinusitis, 2 with acute otitis media, 1 with cervical abscess and 2 with urinary tract infection complexed type) were evaluated as excellent in 7, good in 4 and fair in 1, with an efficacy rate of 91.7%. Seventeen causative organisms found in 10 patients (Haemophilus influenzae in 4, Branhamella catarrhalis in 3, Streptococcus pneumoniae in 2, Pseudomonas aeruginosa in 2, Staphylococcus aureus in 1, alpha-Streptococcus in 1, Corynebacterium sp. in 1, Peptostreptococcus micros in 1 and Klebsiella pneumoniae in 2) were eradicated except 2 strains (S. aureus and P. aeruginosa) from 1 patient (patient No. 2). No adverse reactions were observed in any of the 12 patients. 2. MICs of PAPM were examined against 22 clinical isolates (H. influenzae 5, B. catarrhalis 3, alpha-Streptococcus 3, S. pneumoniae 2, Corynebacterium sp. 2, S. aureus 1, P. aeruginosa 1, P. micros 1, Enterobacter cloacae 1, Escherichia coli 1, Group D Streptococcus 1 and Staphylococcus epidermidis 1) from children with bacterial infections. PAPM showed a good antibacterial activity comparable to the activity of cefoperazone (CPZ) against S. pneumoniae strains relatively tolerant to penicillins. However, the activity of PAPM against H. influenzae was somewhat weaker than that of CPZ. 3. Pharmacokinetic studies.(ABSTRACT TRUNCATED AT 250 WORDS)