Magnetic droplet soliton pairs.

We demonstrate magnetic droplet soliton pairs in all-perpendicular spin-torque nano-oscillators (STNOs), where one droplet resides in the STNO free layer (FL) and the other in the reference layer (RL). Typically, theoretical, numerical, and experimental droplet studies have focused on the FL, with any additional dynamics in the RL entirely ignored. Here we show that there is not only significant magnetodynamics in the RL, but the RL itself can host a droplet driven by, and coexisting with, the FL droplet. Both single droplets and pairs are observed experimentally as stepwise changes and sharp peaks in the dc and differential resistance, respectively. While the single FL droplet is highly stable, the coexistence state exhibits high-power broadband microwave noise. Furthermore, micromagnetic simulations reveal that the pair dynamics display periodic, quasi-periodic, and chaotic signatures controlled by applied field and current. The strongly interacting and closely spaced droplet pair offers a unique platform for fundamental studies of highly non-linear soliton pair dynamics.

More than time: travel time to the delivery ward and maternal outcomes - onset of labour, postpartum haemorrhage and obstetric anal sphincter injury.

BACKGROUND: Closing delivery units increases travel time for some women. Whether increased travel time is associated with maternal outcomes is important for understanding the consequences of such closures. Previous studies are limited in measuring travel time and restricted to the outcome of caesarean section. METHODS: Our population-based cohort includes data from the Swedish Pregnancy Register for women giving birth between 2014 and 2017 (N = 364,630). We estimated travel time from home to the delivery ward using coordinate pairs of actual addresses. The association between travel time and onset of labour was modelled using multinomial logistic regression, and logistic regression was used for the outcomes postpartum haemorrhage (PPH) and obstetric anal sphincter injury (OASIS). FINDINGS: Over three-quarters of women had ≤30 min travel time (median 13.9 min). Women who travelled ≥60 min arrived to care sooner and laboured there longer. Women with further to travel had increased adjusted odds ratio (aOR) of having an elective caesarean section (31-59 min aOR 1.11; 95% confidence interval [CI] 1.07-1.16; ≥60 min aOR 1.25; 95% CI 1.16-1.36) than spontaneous onset of labour. Women (at full term with spontaneous onset) living ≥60 min away had reduced odds of having a PPH (aOR 0.84; 95% CI 0.76-0.94) or OASIS (aOR 0.79; 95% CI 0.66-0.94). INTERPRETATION: Longer travel time increased the odds of elective caesarean section. Women with furthest to travel arrived sooner and spent more time in care; although they had a lower risk of PPH or OASIS, they also tended to be younger, have a higher body mass index and were Nordic born.

SARS-CoV-2 and pregnancy outcomes under universal and non-universal testing in Sweden: register-based nationwide cohort study.

OBJECTIVE: To assess associations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and pregnancy outcomes considering testing policy and test-positivity-to-delivery interval. DESIGN: Nationwide cohort study. SETTING: Sweden. POPULATION: From the Pregnancy-Register we identified 88 593 singleton births, 11 March 2020-31 January 2021, linked to data on SARS-CoV-2-positivity from the Public Health Agency, and information on neonatal care admission from the Neonatal Quality Register. Adjusted odds ratios (aORs) were estimated stratified by testing-policy and test-positivity-to-delivery interval. MAIN OUTCOME MEASURES: Five-minute Apgar score, neonatal care admission, stillbirth and preterm birth. RESULTS: During pregnancy, SARS-CoV-2 test-positivity was 5.4% (794/14 665) under universal testing and 1.9% (1402/73 928) under non-universal testing. There were generally lower risks associated with SARS-CoV-2 under universal than non-universal testing. In women testing positive >10 days from delivery, generally no significant differences in risk were observed under either testing policy. Neonatal care admission was more common (15.3% versus 8.0%; aOR 2.24, 95% CI 1.62-3.11) in women testing positive ≤10 days before delivery under universal testing. There was no significant association with 5-minute Apgar score below 7 (1.0% versus 1.7%; aOR 0.64, 95% CI 0.24-1.72) or stillbirth (0.3% versus 0.4%; aOR 0.72, 95% CI 0.10-5.20). Compared with term births (2.1%), test-positivity was higher in medically indicated preterm birth (5.7%; aOR 2.70, 95% CI 1.60-4.58) but not significantly increased in spontaneous preterm birth (2.3%; aOR 1.12, 95% CI 0.62-2.02). CONCLUSIONS: Testing policy and timing of test-positivity impact associations between SARS-CoV-2-positivity and pregnancy outcomes. Under non-universal testing, women with complications near delivery are more likely to be tested than women without complications, thereby inflating any association with adverse pregnancy outcomes compared with findings under universal testing. TWEETABLE ABSTRACT: Testing policy and time from SARS-CoV-2 infection to delivery influence the association with pregnancy outcomes.

Time-to-delivery and delivery outcomes comparing three methods of labor induction in 7551 nulliparous women: a population-based cohort study.

OBJECTIVE: Determine time-to-delivery and mode-of-delivery in labor induction among women with unripe cervix. STUDY DESIGN: 7551 nulliparous women with singleton deliveries, ⩾37 weeks, Bishop Score ⩽6, induced with dinoprostone, misoprostol or transcervical single balloon catheter. Linear regression analysis was used to estimate mean time-to-delivery with ß-estimates and 95% confidence intervals with adjustments. Multivariable logistic regression analysis was used to calculate odds of cesarean delivery, instrumental vaginal delivery, maternal and neonatal outcomes. RESULTS: Adjusted mean time-to-delivery was 6.9 and 1.5 h shorter, respectively, when inducing labor with balloon catheter (mean 18.3 h, ß -6.9, 95% confidence intervals; -7.6 to -6.3) or misoprostol (mean 23.7 h, ß -1.5, 95% confidence intervals; -2.3 to -0.8) compared with dinoprostone (mean 25.2 h). There were no significant differences in adverse maternal or infant outcomes between induction methods. CONCLUSIONS: Balloon catheter is the most effective induction method with respect to time-to-delivery in nulliparous women at term compared with prostaglandin methods.

Interfacial Dzyaloshinskii-Moriya Interaction in Pt/CoFeB Films: Effect of the Heavy-Metal Thickness.

We report the observation of a Pt layer thickness dependence on the induced interfacial Dzyaloshinskii-Moriya interaction in ultrathin Pt(d_{Pt})/CoFeB films. Taking advantage of the large spin-orbit coupling of the heavy metal, the interfacial Dzyaloshinskii-Moriya interaction is quantified by Brillouin light scattering measurements of the frequency nonreciprocity of spin waves in the ferromagnet. The magnitude of the induced Dzyaloshinskii-Moriya coupling is found to saturate to a value of 0.45 mJ/m^{2} for Pt thicknesses larger than ∼2 nm. The experimental results are explained by analytical calculations based on the three-site indirect exchange mechanism that predicts a Dzyaloshinskii-Moriya interaction at the interface between a ferromagnetic thin layer and a heavy metal. Our findings open up a way to control and optimize chiral effects in ferromagnetic thin films through the thickness of the heavy-metal layer.

A policy of routine umbilical cord blood gas analysis decreased missing samples from high-risk births.

AIM: This study compared obstetric units practicing routine or selective umbilical cord blood gas analysis, with respect to the risk of missing samples in high-risk deliveries and in infants with birth asphyxia. METHODS: This was a Swedish population-based cohort study that used register data for 155 235 deliveries of live singleton infants between 2008 and 2014. Risk ratios and 95% confidence intervals were calculated to estimate the association between routine and selective umbilical cord blood gas sampling strategies and the risk of missing samples. RESULTS: Selective sampling increased the risk ratios when routine sampling was used as the reference, with a value of 1.0, and these were significant in high-risk deliveries and birth asphyxia. The risk ratios for selective sampling were large-for-gestational age (9.07), preterm delivery at up to 36 weeks of gestation (8.24), small-for-gestational age (7.94), two or more foetal scalp blood samples (5.96), an Apgar score of less than seven at one minute (2.36), emergency Caesarean section (1.67) and instrumental vaginal delivery (1.24). CONCLUSION: Compared with routine sampling, selective umbilical cord blood gas sampling significantly increased the risks of missing samples in high-risk deliveries and in infants with birth asphyxia.

Durations of second stage of labor and pushing, and adverse neonatal outcomes: a population-based cohort study.

OBJECTIVE: The associations between duration of second stage of labor, pushing time and risk of adverse neonatal outcomes are not fully established. Therefore, we aimed to examine such relationships. STUDY DESIGN: A population-based cohort study including 42 539 nulliparous women with singleton infants born in cephalic presentation at ⩾37 gestational weeks, using the Stockholm-Gotland Obstetric Cohort, Sweden, and the Swedish Neonatal Quality Register, 2008 to 2013. Poisson regression was used to analyze estimated adjusted relative risks (RRs), with 95% confidence intervals (CIs). Outcome measures were umbilical artery acidosis (pH <7.05 and base excess <-12), birth asphyxia-related complications (including any of the following conditions: hypoxic ischemic encephalopathy, hypothermia treatment, neonatal seizures, meconium aspiration syndrome or advanced resuscitation after birth) and admission to neonatal intensive care unit (NICU). RESULTS: Overall rates of umbilical artery acidosis, birth asphyxia-related complications and admission to NICU were 1.08, 0.63 and 6.42%, respectively. Rate of birth asphyxia-related complications gradually increased with duration of second stage: from 0.42% at <1 h to 1.29% at ≥4 h (adjusted RR 2.46 (95% CI 1.66 to 3.66)). For admission to NICU, corresponding rates were 4.97 and 9.45%, and adjusted RR (95% CI) was 1.80 (95% CI 1.58 to 2.04). Compared with duration of pushing <15 min, a duration of pushing ⩾60 min increased rates of acidosis from 0.57 to 1.69% (adjusted RR 2.55 (95% CI 1.51 to 4.30)). CONCLUSION: Prolonged durations of second stage of labor and pushing are associated with increased RRs of adverse neonatal outcomes. Clinical assessment of fetal well-being is essential when durations of second stage and pushing increases.

Population-based reference curve for umbilical cord arterial pH in infants born at 28 to 42 weeks.

OBJECTIVE: The objective of the study was to examine normal variations of umbilical cord arterial pH by gestational age (GA). STUDY DESIGN: Population-based cohort study of 46 199 infants born from 2008 to 2014 in Stockholm, Sweden, with GA 28 to 42 weeks, Apgar score ⩾7 at 5 min, non-instrumental vaginal delivery, and birth weight for GA⩾3rd and ⩽97th percentile. Quantile regression was used to investigate the associations between GA and infant sex, and pH. RESULTS: The mean umbilical cord arterial pH (s.d.) was 7.29 (0.10), 7.27 (0.07), 7.25 (0.07) and 7.23 (0.07) among infants born at 28 to 31, 32 to 36, 37 to 41 and 42 weeks, respectively. Arterial pH decreased linearly with increasing GA, and female infants had higher pH than male infants (P<0.001). CONCLUSION: Umbilical cord arterial pH varied in a linear fashion by GA and was influenced by infant sex. The provided reference curve taking GA into account may yield a more accurate definition of acidosis at birth.

Risk factors for anal sphincter tears in vacuum-assisted delivery.

OBJECTIVE: The aim of the present study was to describe the prevalence of anal sphincter tears (AST) in relation to obstetric management and technique during vacuum extraction deliveries (VE) (re: indications, the station of the fetal head at application of the cup, number of tractions, the length for the extraction, cup detachments, pain relief, episiotomy, fetal presentation, and experience of the operator) as well as maternal and infant anthropometrics. METHODS: Descriptive study. Data on six hundred vacuum extraction deliveries were consecutively collected from six different delivery units in Sweden. Each unit contributed with data on 100 deliveries. The final study population included 596 women who delivered by vacuum extraction. RESULTS: There was no correlation between the management of the vacuum extraction and risk for anal sphincter tear. Women from Africa had nearly a fourfold risk for anal sphincter tear during vacuum-assisted delivery compared with Swedish-born women (OR 3.82 CI 1.47-9.89). Compared with infants with birth weight less than 4000 g, birth weight above 4000 g was associated with increased risk of AST (OR 1.87 CI 1.06-3.28). CONCLUSIONS: In this study, the obstetric management in VE-assisted deliveries did not impact the risk of AST.

Hypophysectomy and/or peroxisome proliferators strongly influence the levels of phase II xenobiotic metabolizing enzymes in rat testis.

The objectives of the present work were to determine the influence of hypophysectomy and/or peroxisome proliferators (PP) on certain xenobiotic-metabolizing enzyme activities, i.e. glutathione transferases (GST), glutathione peroxidase (GPX), phenol sulphotransferases (pSULT), phenol UDP-glucuronosyl transferases (pUGT), catalase, NADP(H) quinone oxidoreductase (QR) and epoxide hydrolases (EH) in the rat testes. Adult male rats, hypophysectomized and their sham-operated controls, were treated for 10 days with clofibrate (0.5%), perfluorooctanoic acid (0.05%, PFOA), acetylsalicylic acid (1%, ASA) and di(2-ethylhexyl)phthalate (2%, DEHP) in their diet. The results show that, in addition to both body and testis weight, hypophysectomy caused dramatic changes in most of the xenobiotic-metabolizing enzyme activities, which have been measured here. The most pronounced effects were seen in cytosolic QR (2.2-fold increase), pUGT (95% reduction), pSULT (75% reduction), mitochondrial catalase (75% reduction), microsomal EH (70% reduction) and microsomal GST (55% reduction). Treatment with PP, i.e. perfluorooctanoic acid (PFOA), clofibrate, acetyl salicylic acid (ASA) and di(2-ethylhexyl)phthalate (DEHP) showed varied effects on the xenobiotic-metabolizing enzyme activities, the highest effects (10-60% reduction) were seen in sham-operated animals. These effects were not so pronounced or were not seen in hypophysectomized rats except for the case of PFOA treatment, which caused increases of enzyme activities. The highest increases were seen with microsomal GST (70%), GPX (75%) and cytosolic EH (75%). It is concluded from these experiments that the regulation of several xenobiotic-metabolizing enzymes in the rat testis is affected by the pituitary and/or pituitary hormones and that different peroxisome proliferators have variable effects on the levels of these xenobiotic-metabolizing enzymes. The general trend of reduction in enzyme activities implies that the testis is less protected under conditions that can perturb hormonal status.

Evidence for mitochondrial metabolism of 7,12-dimethylbenz(a)anthracene in porcine ovaries: comparison with microsomal metabolism.

7,12-dimethylbenz(a)anthracene (DMBA) causes necrosis in endocrine organs. DMBA metabolism in follicles and corpora lutea from porcine ovaries was demonstrated not only in the microsomal but also in the mitochondrial fraction, in contrast to what has been found in the rat ovary. Maximal activities were present in these fractions of the corpus luteum, with specific activities of 5.9 and 2.2 pmol/min x mg protein, respectively. DMBA metabolism in mitoplasts, i.e. mitochondrial inner membranes, proved to be more than 10-fold higher than the corresponding activity in the mitochondrial fraction. The purities of the subcellular fractions were assessed by measurements of marker enzymes. 17-42% of the mitochondrial DMBA metabolism was concluded to be due to microsomal contamination. In the mitoplast fraction such contamination was only 0.18-2.8%. Ellipticine and alpha-naphthoflavone reduced the metabolism of DMBA in the luteal microsomal fraction by 95 and 77%, respectively. In mitochondria the inhibition by these agents was 63 and 30%, respectively. Indomethacine and estradiol decreased microsomal DMBA metabolism by 53 and 52%, respectively. In mitochondria the inhibition was 52 and 23%, respectively. None of these inhibitors affected the DMBA metabolism by the mitoplast fraction.

Effects of peroxisome proliferators and/or hypothyroidism on xenobiotic-metabolizing enzymes in rat testis.

The objectives of the present work were to study the effects of certain peroxisome proliferators on xenobiotic-metabolizing enzyme activities in the testes of normal and hypothyroid rats, i.e. phenol sulfotransferases (pST), phenol UDP-glucuronosyl transferases (pUDPGT), glutathione transferases (GST), catalase, epoxide hydrolase (EH), glutathione peroxidase (GPX) and NAD(P)H quinone oxidoreductase (QR). Adult male rats (normal and hypothyroid) were treated for 10 days with clofibrate (0.5%), perfluorooctanoic acid (0.5%, PFOA), acetylsalisylic acid (1%, ASA) and di(2-ethylhexyl)phthalate (2%, DEHP) in their diet. The results show that treatment of normal rats with peroxisome proliferators dramatically affects the activities of xenobiotic-metabolizing enzymes (40-60% reduction). The highest effects are seen in catalase activity (50-60% with PFOA and ASA), pUDPGT (55% with PFOA), pST (55% with PFOA) and QR (50% with DEHP). These effects are not seen or are weaker after induction of hypothyroidism. Taken together, it is concluded that different classes of peroxisome proliferators have different effects on rat testicular xenobiotic-metabolizing enzymes.

Cytochrome P450 genes expressed in porcine ovaries: identification of novel forms, evidence for gene conversion, and evolutionary relationships.

In order to identify cytochrome P450s that are expressed in porcine ovaries, the RT/PCR methodology was used with a set of primers that corresponds to two conserved regions of the 2C gene subfamily of these enzymes. Five independent cDNA clones were isolated from preovulatory follicles (PF1, PF11, PF13, PF14, PF15) and six from the corpus luteum (CL1, CL6, CL7, CL8, CL12, CL13). The structural identities categorize these 11 P450s into two groups, group A consisting of PF1, CL7 and CL8 and group B consisting of the remaining clones. In addition, segments that are apparently interchanged between the clones were also revealed, implicating gene conversion events that have homogenized the sequence of these P450s. Furthermore, although the larger group of these porcine enzymes (group B forms) are structurally very similar to the known human P450s of the 2C gene subfamily, the group A forms are much more distantly related, implying that the 2C P450s might have evolved differently in the two species.

Hormonal influences of detoxication in the rat ovary on enzymes in comparison with the liver.

Variations in the total capacity of the rat ovary to metabolize xenobiotics during different phases of the estrous cycle were studied. The level of the conjugating enzymes, phenol UDP-glucuronosyltransferase (pUDPGT; EC 2.4.1.17), phenol sulfotransferase (pST; EC 2.8.2.1) and glutathione transferases (EC 2.5.1.18) was determined in the ovary and compared with the corresponding hepatic activities. In addition, catalase (EC 1.11.1.6) and NAD(P)H: quinone oxidoreductase (EC 1.6.99.2) two other detoxifying enzymes, were assayed. In order to study the hormonal influences on detoxifying enzymes, mature rats were characterized with respect to their stage in the estrous cycle. Immature rats were treated with pregnant mare's serum gonadotropin (PMSG) for 2 or 3 days to enrich the ovaries in preovulatory follicles or corpora lutea, respectively. The present study demonstrates that ovarian pUDPGT and pST activities are increased 936% and 175%, respectively, in ovaries enriched in corpora lutea compared to ovaries from untreated immature rats. Increases in these activities in mature rats during the metestrous stage of the estrous cycle compared to the proestrous stage were also noted. In the liver pUDPGT activity is increased significantly (1.6-fold) in immature rats with ovaries enriched in preovulatory follicles compared to untreated rats. Both ovarian pST and pUDPGT activities increased in mature rats treated with PMSG ("hyperstimulated"), while in the liver only pST was increased by such treatment. Ovarian glutathione transferase activity proved not to be dependent on the hormonal fluctuations associated with the estrous cycle. However, in the liver of mature rats treated with PMSG, this activity increased 2-fold compared to the untreated immature rats. The catalase activity found in the ovarian mitochondrial fraction was approx. 10-fold higher than in the cytosolic fraction, independent of the hormonal status. Moreover, we found a significant 1.4-fold increase in peroxisomal catalase activity in the mitochondrial fraction of immature rats treated with PMSG, both when enriched in preovulatory follicles and in corpora lutea. In the liver cytosolic catalase activity decreased several-fold in immature rats following PMSG treatment. We did not find any variations in ovarian NAD(P)H: quinone oxidoreductase activity during the estrous cycle, whereas in the liver this activity decreased in the luteal phase, as it did in mature rats treated with PMSG. From this study and earlier investigations in our laboratory, we conclude that cyclic variations due to hormones of the estrous cycle of the major 7,12-dimethylbenz(a)anthracene (DMBA)-metabolizing phase I enzymes in the ovary are not accompanied by increases in the activities of the corresponding phase II enzymes.(ABSTRACT TRUNCATED AT 400 WORDS)

A novel 34 kDa glutathione-binding protein in mature rat ovary.

A novel protein that binds to a glutathione-Sepharose affinity column has been detected in mature, but not immature, rat ovary. This protein could be resolved from all identifiable components when the affinity-purified material, containing primarily glutathione transferases, was analyzed on reversed phase-HPLC. The unidentified protein migrated with an apparent molecular weight of 34 kDa on SDS-PAGE. After purification by affinity chromatography and subsequent preparative electrophoresis, the protein was subjected to N-terminal amino acid sequence analysis. The sequence obtained demonstrated a high degree of homology with an internal amino acid sequence in human carbonyl reductase (EC 1.1.1.184).

Metabolism of polycyclic aromatic hydrocarbons to mutagenic species by rat and porcine ovarian granulosa cells: detection by cocultivation with V79 Chinese hamster cells.

The capacity of ovarian granulosa cells from rat and pig to release reactive metabolites produced from polycyclic aromatic hydrocarbons with the ability to cause mutations in neighbouring cells has been studied. For this purpose we have used cocultivation with V79 Chinese hamster cells as a detection system. The cells were treated with two different polycyclic aromatic hydrocarbons (PAHs), 7,12-dimethylbenz(a)anthracene (DMBA) or (-)-trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene (BP-7,8-diol). The resulting mutation frequency in the V79 cells after cocultivation, as a function of granulosa cell number, DMBA, or BP-7,8-diol concentration and time, was determined. The progesterone concentration in the medium after cocultivation was also analyzed as a measure of the differentiation of the granulosa cells. These studies demonstrate an increasing frequency of mutations in the V79 cells with an increasing number of granulosa cells. The maximal number of mutations were achieved with a DMBA or BP-7,8-diol concentration of 5 or 2 microM, respectively. The optimal cocultivation time was 24 h. These results clearly show that the granulosa cells can bioactivate PAHs to reactive metabolites with the capacity to migrate into surrounding cells and cause mutations in these cells. Compounds metabolized to mutagenic products by granulosa cells might thus cause mutations in the neighbouring germ cells, with possible consequences for the offspring.

Nutritional assessment in anemic hemodialysis patients treated with recombinant human erythropoietin.

Nutritional status was assessed in 25 anemic hemodialysis patients before and during erythropoietin treatment. Nutritional assessment included regular blood chemistry determinations, anthropometric measurements, analysis of protein content in skeletal muscle, and estimation of daily protein intake from protein catabolic rate determinations (using urea kinetic modelling) and dialysis efficiency for urea. These measurements were done immediately prior to erythropoietin treatment, after anemia correction and after one year of maintenance erythropoietin treatment. Both relative body weights and subcutaneous fat stores were low at the start, but increased significantly (p less than 0.05) during the study. Sixteen of the 25 patients gained weight and eight patients lost weight. The patients with weight gain had at the start of the study low weight indices (body weight 89.9 +/- 7.6% of ideal body weight, body mass index 20.6 +/- 1.6), significantly (p less than 0.005) lower than the patients with weight loss. Although protein malnutrition was not obvious from arm anthropometrics, alkali soluble protein/DNA ratio or from serum albumin determinations, ASP/DNA ratio, increased in three of five patients investigated after one year on erythropoietin treatment. Neither protein catabolic rate nor dialysis efficiency changed significantly during the study. We conclude that anemia correction with erythropoietin has a positive effect on malnutrition in hemodialysis patients. In patients with underweight, an adjustment of fat stores was initially observed, followed possibly by an improvement in muscle protein content.

Protein and amino acid metabolism during early starvation as reflected by excretion of urea and methylhistidines.

Endogenous excretion of nitrogenous products was studied during early starvation in six healthy, nonobese subjects after six days on a well-defined diet, designed to achieve net protein balance and an adequate calorie supply. The diet contained 0.5 g myofibrillar-free protein and 35 kcal/kg body weight. The subjects then fasted for three days. Urine was collected for 24-hour periods and analyzed for urea, ammonia, 3-methylhistidine, and 1-methylhistidine. Blood glucose and serum urea levels were measured daily. In a second group of subjects, muscle biopsies for determination of free amino acid concentrations were taken in the overnight fasted state and after three days of fasting. During the period with a balanced diet, urea production fell initially and stabilized after two to three days at a level of 146 +/- 15 mmol/24 h. During the period of fasting, serum urea increased from 3.0 +/- 0.4 to a maximum value of 6.2 +/- 0.7 mmol/L and urea production rose markedly, to a peak of 293 +/- 16 mmol/24 h. Ammonia excretion was 24 +/- 2 mmol/24 h before and 71 +/- 13 mmol/24 h after three days of fasting. 3-Methylhistidine excretion was stable before fasting and then rose from 154 +/- 17 to 198 +/- 17 mumol/24 h. 1-Methylhistidine excretion was unchanged during fasting. Blood glucose levels were stable at 4.8 +/- 0.2 mmol/L before fasting and then fell to 3.7 +/- 0.3 mmol/L. Intracellular concentrations of amino acids in skeletal muscle decreased markedly during fasting; after three days of fasting the glutamine concentration had fallen by 34%.(ABSTRACT TRUNCATED AT 250 WORDS)