Measurement of the Positive Muon Anomalous Magnetic Moment to 0.20 ppm

We present a new measurement of the positive muon magnetic anomaly, a_{μ}≡(g_{μ}-2)/2, from the Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, ω[over ˜]_{p}^{'}, and of the anomalous precession frequency corrected for beam dynamics effects, ω_{a}. From the ratio ω_{a}/ω[over ˜]_{p}^{'}, together with precisely determined external parameters, we determine a_{μ}=116 592 057(25)×10^{-11} (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a_{μ}(FNAL)=116 592 055(24)×10^{-11} (0.20 ppm). The new experimental world average is a_{μ}(exp)=116 592 059(22)×10^{-11} (0.19 ppm), which represents a factor of 2 improvement in precision.

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm

We present the first results of the Fermilab National Accelerator Laboratory (FNAL) Muon g-2 Experiment for the positive muon magnetic anomaly a_{μ}≡(g_{μ}-2)/2. The anomaly is determined from the precision measurements of two angular frequencies. Intensity variation of high-energy positrons from muon decays directly encodes the difference frequency ω_{a} between the spin-precession and cyclotron frequencies for polarized muons in a magnetic storage ring. The storage ring magnetic field is measured using nuclear magnetic resonance probes calibrated in terms of the equivalent proton spin precession frequency ω[over ˜]_{p}^{'} in a spherical water sample at 34.7 °C. The ratio ω_{a}/ω[over ˜]_{p}^{'}, together with known fundamental constants, determines a_{μ}(FNAL)=116 592 040(54)×10^{-11} (0.46 ppm). The result is 3.3 standard deviations greater than the standard model prediction and is in excellent agreement with the previous Brookhaven National Laboratory (BNL) E821 measurement. After combination with previous measurements of both μ^{+} and μ^{-}, the new experimental average of a_{μ}(Exp)=116 592 061(41)×10^{-11} (0.35 ppm) increases the tension between experiment and theory to 4.2 standard deviations.

A further consideration in the application of an analysis-of-variance model for the intrasubject replication design

It is argued that the analysis-of-variance model is inappropriate for assessing treatment effects in single-subject designs. In particular, such designs are demonstrated to violate the crucial assumption concerning the statistical independence of observations. Alternative methods of data analysis are suggested.

Thymosin beta 10 levels in developing human brain and its regulation by retinoic acid in the HTB-10 neuroblastoma

Human fetal brain expresses high levels of a polypeptide identified by protein biochemistry and molecular cloning as thymosin beta 10. Within the first 18 months after birth, the thymosin beta 10 content of human brain falls to undetectable levels. In order to establish the molecular basis of this process we screened a number of human tumor cell lines derived from the nervous system for the presence of thymosin beta 10. All of the cell line expressed authentic thymosin beta 10. However, in the HTB-10 neuroblastoma, retinoic acid caused a reduction in the level of thymosin beta 10. This effect of the retinoid was conditional upon its continual presence in the tissue culture medium and was not evident in the other cell lines examined. These results suggest that the thymosin beta 10 gene may be a target for retinoids in the developing nervous system.

Glutamate receptor agonists increase the expression of Fos, Fra, and AP-1 DNA binding activity in the mammalian brain

Administration of convulsant doses of Metrazole (pentylenetetrazol) and picrotoxin, as well as maximal electroshock, results in a rapid but transient increase in c-fos mRNA in mouse brain. Elevation of c-fos mRNA is followed by the accumulation and subsequent disappearance of Fos, the protein encoded by c-fos. In addition, immunoblots reveal the induction of two additional proteins that are antigenically related to Fos (Fra, Fos-related antigens). Fos and the various Fra appear and disappear in a staggered manner over an 8 hour period, such that at longer times after stimulation the brain contains no Fos but relatively large amounts of Fra (the latter being designated here by their apparent molecular weights, Fra-46K and Fra-35K). Previous studies have established that Fos, as well as several Fra, contribute to transcription factor AP-1 nucleoprotein complexes along with Jun, the product of the jun proto-oncogene. The appearance in brain of Fos and Fra coincides with a protracted increase in total AP-1 DNA binding activity, indicating that all the Fos-like proteins can participate in AP-1 complexes. Furthermore, the molecular composition of these complexes alters with time after stimulation. The induction of c-fos by Metrazole is blocked or attenuated by known anticonvulsants such as diazepam and valproate as well as the N-methyl-D-aspartate (NMDA) receptor antagonists, 2-amino-5-phosphonovaleric acid (APV) and MK-801. This suggests that fos induction might involve stimulation of a glutamate receptor. This conclusion was strengthened by the observations that two glutamate receptor agonists, kainic acid and NMDA, induced c-fos expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular cloning of a neuron-specific transcript and its regulation during normal and aberrant cerebellar development

PEP-19 is a brain-specific polypeptide whose levels increase dramatically during the late maturation of the rodent nervous system. By using immunocytochemistry, PEP-19 is shown to be localized to several regions of the central nervous system, notably cerebellum, thalamus caudate putamen, and olfactory bulb. We have isolated a 0.5-kilobase cDNA clone that encodes the entire PEP-19 protein sequence, making this one of the smallest primary transcripts and translation products ever identified in eukaryotes. The cDNA was used to investigate the developmental expression of PEP-19 in rodent brain. PEP-19 mRNA rises from low levels at embryonic day 17 of gestation in the rat to a plateau value by day 18 postpartum. This mirrored the levels of the protein determined by radioimmunoassay. Since the rise coincided with the formation of synaptic contacts onto Purkinje cells (a major site of PEP-19 expression), the hypothesis was tested that the activity and/or presence of afferent input modulated PEP-19 expression. Parallel fiber innervation was disrupted either by killing granule cells with the cytostatic agent methylazoxymethanol or by examining PEP-19 levels in cerebellar granuloprival mutant mice (reeler and weaver). The influence of climbing fiber input was assessed by either eliminating them with 3-acetylpyridine or stimulating them with harmaline in both neonatal and mature rats. None of the above altered PEP-19 gene expression in cerebellum, leading us to propose that the signals triggering the PEP-19 gene do not emanate from granule cells or neurons in the olivary nucleus. However, preliminary evidence suggests that PEP-19 is under posttranscriptional regulation.

Cerebellin and related postsynaptic peptides in the brain of normal and neurodevelopmentally mutant vertebrates

The rat cerebellum was previously shown to contain two polypeptides, a hexadecapeptide termed cerebellin and an apparent metabolite des-Ser1-cerebellin. The cerebellins have a high degree of sequence homology with residues 625-641 of the polyimmunoglobulin (polyIg)-receptor adjacent to its membrane-spanning domain. Since the cerebellins are localized in Purkinje cells and enriched in synaptosomes, this might indicate that cerebellin is a specific proteolytic cleavage fragment of a synaptic protein involved in the transcytosis of an unknown ligand. Using a specific cerebellin radioimmunoassay described here combined with high-performance liquid chromatography, cerebellin immunoreactivity could be demonstrated in the cerebella of all vertebrates examined from man to chicken. Cerebellin immunoreactivity is localized to Purkinje cells in the rat, mouse, and chicken. Furthermore, cerebellin expression is under developmental regulation in both the chicken and mouse. In addition, neurodevelopmental mutations of mice that eliminate granule cells cause a large deficit in cerebellin levels, suggesting some form of transneuronal regulation.

Monoclonal antibodies to mammalian carnosine synthetase

A set of mouse monoclonal antibodies has been generated against rabbit muscle carnosine synthetase. The immunoreactivity of these antibodies has been characterized using an immunoassay that permits the separation and direct measurement of the synthetase activity on a second antibody bead complex. Four IgG monoclonal antibodies bind the carnosine synthetase activity from muscle of all mammals tested (mouse, rat, rabbit, cow, dog, and monkey) but not that from chicken muscle. This indicates the mammalian enzymes share epitopes that are absent from the avian enzyme. In addition, relative tissue levels of synthetase activity can be quantified with this immunoassay. Thus, high levels of carnosine synthetase activity are immunoprecipitated from the olfactory tissues of both rat and rabbit. Synthetase activity is generally lower in other tissues (muscle, brain, heart, liver, and gut). Nevertheless, the cross-reactivity of the synthetase from several tissues (olfactory mucosa, muscle, brain, gut, heart, and liver) of a single species indicates the enzyme protein contains similar epitopes in these tissues. Immunoaffinity purification of this low-abundance, unstable enzyme should now be possible for subsequent studies of structure and regulation.

Synthesis of thymosin beta 4 by peritoneal macrophages and adherent spleen cells

Thymosin beta 4, previously identified as a component of thymosin fraction 5 isolated from calf thymus, is synthesized by peritoneal macrophages derived from rats or mice, including cells from nu/nu mice. Identification of thymosin beta 4 containing [35S]methionine was based on its retention time in reverse-phase HPLC and the recovery of radioactivity in peptides generated by mild acid hydrolysis or by digestion with trypsin. Thymosin beta 4 is also synthesized by rat and mouse spleen cells, and evidence is presented for its release from these cells.

Thymosin beta 4: a ubiquitous peptide in rat and mouse tissues

Thymosin beta 4, recently isolated from calf thymus, is present in a number of rat and mouse tissues, including spleen, thymus, brain, lung, liver, and heart muscle. High concentrations are found in peritoneal macrophages, suggesting that its occurrence in other tissues may be related to the presence of macrophages or macrophage-like cells in these tissues. The conclusion that "thymosin" beta 4 does not originate solely in the thymus gland is supported by the high concentrations found in tissues of athymic (nu/nu) mice.

Catecholamines in the Vasculature of the Rat and Rabbit: Dopamine, Norepinephrine, Epinephrine

A highly sensitive radioenzymatic assay for the measurement of catecholamines in small blood vessels was applied to the measurement of the levels of norepinephrine (NE), dopamine (DA) and epinephrine (E). The results showed the presence of NE, E and DA in all segments of rat or rabbit vascular tissue analyzed. The predominant catecholamine in the vasculature from both species was NE, and the contents of E and DA were similar for most vessels. Unexpectedly large concentrations of E were associated with rabbit blood vessels.

Chemical deafferentation of the olfactory bulb: plasticity of the levels of tyrosine hydroxylase, dopamine and norepinephrine

The laminar distribution of tyrosine hydroxylase activity, dopamine and norepinephrine was determined in the dog olfactory bulb. The levels of tyrosine hydroxylase activity and dopamine were highest in the glomerular layer, whereas norepinephrine appeared to be more uniformly distributed across the layers. A similar distribution was observed within the mouse olfactory bulb. Following deafferentation of the mouse olfactory bulb, the levels of tyrosine hydroxylase activity and dopamine declined, while norepinephrine levels showed a transient increase. Subsequent to regeneration of the olfactory nerve, these levels returned to control values. The levels of tyrosine hydroxylase activity and of dopamine were very low or non-detectable in the olfactory epithelium, which contains the olfactory receptor neuron perikarya. The data obtained indicate that tyrosine hydroxylase activity and dopamine content in the bulb are more tightly coupled to each other than either is to norepinephrine content. Since the two catecholamines are in two different classes of neurons, this implies that the bulk of the tyrosine hydroxylase activity in the bulb is associated with the dopamine-containing neurons. Finally, our data are consistent with a transsynaptic control mechanism of the tyrosine hydroxylase activity and dopamine level in the olfactory bulb.

Experimental diabetes: alterations in circulating dopamine-beta-hydroxylase and norepinephrine

Dopamine-beta-hydroxylase (DBH) activity is increased at least 5-fold in the serum of rats with experimental diabetes produced by Streptozotocin or Alloxan. The increased DBH activity persisted for 7 months. Dialysis did not reduce the elevated activity. Based on a large increase in the maximal velocity of the enzyme reaction and immunoprecipitation studies, there appears to be increased amounts of DBH in the serum of diabetic rats. Thyroxin and triiodothyronine concentrations were reduced in diabetic serum but replacement doses of these hormones did not correct the high DBH activity. In contrast, adrenalectomy or insulin administration prevented the diabetes and elevations of circulating DBH. Circulating norepinephrine levels in arterial and venous blood were measured at 4 and 16 weeks after the onset of diabetes and elevated only in venous blood at the early time interval. In summary, circulating DBH levels were increased in experimental diabetes but did not correlate with circulating norepinephrine levels. Further studes are required to differentiate between the possibilities of increased sympathetic nervous system activity and altered DBH turnover in experimental diabetes.

Altered disposition of vascular catecholamines in hypertensive (DOCA-salt) rats

The levels of norepinephrine (NE), dopamine (DA) and epinephrine (E) in the vasculature of hypertension (DOCA-SALT) and normotensive rats were determined by radioenzymatic assay. Significant decreases in the NE content of the mesenteric artery, renal artery and cardiac tissue from DOCA-Salt treated rats were found. In contrast the NE content of the inferior vena cava, abdominal aorta and mesenteric vein were not significantly decreased in the DOCA-Salt treated rats. There was no evidence of an altered disposition of DA and E in the vasculature of DOCA-Salt treated rats. The results of the study indicate that NE is selectively depleted in the cardiovascular system of this model of experimental hypertension and it is proposed that this property reflects different functional roles of individual elements of the vasculature in the DOCA-Salt hypertensive rat.

Pharmacokinetics of naloxone in rats and in man: basis for its potency and short duration of action

Using a specific and sensitive radioimmunoassay, naloxone concentrations in the brains and sera of rats were measured at intervals for four hours following iv injection (5 mg/kg). Decrement curves of naloxone were compared with those after iv injection of morphine (5 mg/kg). Serum concentration of naloxone at 5 minutes was 1.45 +/- 0.1 mug/ml (mean +/- SE) and that of morphine was 1.0 +/- 0.08 mug/ml. Their serum half-lives from one to four hours were approximately the same, 30-40 minutes. With naloxone, the brain-serum concentration ratios ranged from 2.7 to 4.6. Concentration of naloxone in the brain declined parallel to that in the serum. However, with morphine the initial brain concentration was approximately one tenth that in the serum (0.096 +/- 0.04 mug/ml). The brain morphine concentration was sustained for one hour, while serum morphine concentrations declined from 1.0 to 0.19 mug/ml during this period. Two minutes after iv injection of naloxone HCl (0.4 mg) in nine healthy volunteers, the serum drug concentration was 0.01 +/- .001 mug/ml. At 5 minutes, 97 per cent of the administered dose was no longer found in the serum, the serum concentration being 0.004 +/- .0003 mug/ml. From 20 minutes to two hours after injection, the calculated mean serum half-life of naloxone was 64 minutes. These results suggest that the rapid penetrance of naloxone into the brain and the high brain-serum concentration ratio contribute to its rapid onset of action and potency as a narcotic antagonist. The rapid decline of naloxone concentration in the brain found in the animal model, in contrast to that of morphine, could be the basis for its relatively short duration of action.

Disposition of naloxone: use of a new radioimmunoassay

Understanding of the pharmacology of the narcotic antagonist naloxone has been limited by the lack of a convenient and sensitive method of assay. A radioimmunoassay for naloxone has been developed and is described. It is applicable for drug analysis in either serum or brain. The limit of sensitivity of the assay was 0.1 ng. Naloxone glucuronide, noroxymorphone (nor-naloxone) and morphine were not recognized by the antibody whereas naltrexone and 6-hydroxynaloxone were able to displace naloxone-3H from the antibody. The assay was of sufficient sensitivity to follow the serum levels of naloxone in man for up to 2 hours after an i.v. injection of 0.4 mg. In animal studies, the biologic half-lives of naloxone or morphine (5 mg/kg) were compared after s.c. injection in rats. The peak serum levels A (1 mu/mo), time to peak serum levels (less than 1/2 hour), and serum half-life (40 minutes) were comparable. However, the brain entry and egress of the two compounds differed markedly. Peak brain levels of naloxone occurred within 15 minutes and had declined by 50% within 1 hour, whereas the peak brain levels of morphine were sustained for up to 2 hours. At peak serum levels, the brain/serum ratio for morphine was 0.1 whereas for naloxone it was 15 times greater. We suggest the high brain/serum ratio of naloxone contributes to its potency whereas the rapid egress from the brain is important in the short duration of action of naloxone.

The diposi tion of morphine in surgical patients

The disposition of serum morphine following administration of 10 mg/70 kg was determined by a sensitive and specific radioimmunoassay in 31 anethetized surgical patients ranging in age from 23 to 75 yr. Following iv injection, 93 per cent of the morphine disappeared from the serum within 5 min. The early serum levels of the drug (2 min) correlated directly with the patients' ages (r equal to 0.63, p smaller than 0.01). Patient 23 to 50 yr of age averaged 0.29 mug/ml, whereas patients 51 to 75 ur of age averaged 70 percent higher, 0.49 mug/ml. The serum half-life between 10 and 240 min was independent of age and averaged about 2 hr after either iv or im administration. Following im admininstration, morphine was rapidly absorbed, with peak levels occurring within 10 to 20 min. The decline in morphine serum levels paralleled the decline in morphine analgesia and was coincident with the apperance of morphine glucuronide in the serum. These studies demonstrate the applicability and specificity of the radioimmunoassay for morphine and suggest that serum levels of morphine may be a useful and objective indicator of its pharmacologic activity.