Histamine, mast cell tryptase and post-exercise hypotension in healthy and collapsed marathon runners.

PURPOSE: Heat stress exacerbates post-exercise hypotension (PEH) and cardiovascular disturbances from elevated body temperature may contribute to exertion-related incapacity. Mast cell degranulation and muscle mass are possible modifiers, though these hypotheses lack practical evidence. This study had three aims: (1) to characterise pre-post-responses in histamine and mast cell tryptase (MCT), (2) to investigate relationships between whole body muscle mass (WBMM) and changes in blood pressure post-marathon, (3) to identify any differences in incapacitated runners. METHODS: 24 recreational runners were recruited and successfully completed the 2019 Brighton Marathon (COMPLETION). WBMM was measured at baseline. A further eight participants were recruited from incapacitated runners (COLLAPSE). Histamine, MCT, blood pressure, heart rate, body temperature and echocardiographic measures were taken before and after exercise (COMPLETION) and upon incapacitation (COLLAPSE). RESULTS: In completion, MCT increased by nearly 50% from baseline (p = 0.0049), whereas histamine and body temperature did not vary (p > 0.946). Systolic (SBP), diastolic (DBP) and mean (MAP) arterial blood pressures and systemic vascular resistance (SVR) declined (p < 0.019). WBMM negatively correlated with Δ SBP (r = - 0.43, p = 0.046). For collapse versus completion, there were significant elevations in MCT (1.77 ± 0.25 µg/L vs 1.18 ± 0.43 µg/L, p = 0.001) and body temperature (39.8 ± 1.3 °C vs 36.2 ± 0.8 °C, p < 0.0001) with a non-significant rise in histamine (9.6 ± 17.9 µg/L vs 13.7 ± 33.9 µg/L, p = 0.107) and significantly lower MAP, DBP and SVR (p < 0.033). CONCLUSION: These data support the hypothesis that mast cell degranulation is a vasodilatory mechanism underlying PEH and exercise associated collapse. The magnitude of PEH is inversely proportional to the muscle mass and enhanced by concomitant body heating.

Effects of adjunctive zonisamide treatment on weight and body mass index in children with partial epilepsy.

BACKGROUND: Zonisamide has been associated with weight loss in children and adults. AIMS OF THE STUDY: To assess the effects of adjunctive zonisamide on weight and body mass index (BMI) in children with partial epilepsy. METHODS: A subanalysis was conducted of a Phase III trial and extension study, in which children with partial epilepsy received adjunctive zonisamide (target dose 8 mg/kg/day; maximum 500 mg/day). Changes in weight were correlated with skeletal development and sexual maturation. RESULTS: Overall, 179 children (93 male, 86 female; age 6-18 years) received zonisamide (mean duration 370.6 days). Weight loss ≥ 5% was reported for 64 of 179 (35.8%) zonisamide-treated children. Of these, 46.9% were overweight/obese at study entry, compared with 23.4% at study end (P = 0.0007); 48.4% had normal weight at study entry, compared with 65.6% at study end (P = 0.03). Three patients were underweight at study entry, and four more became underweight by study end. No consistent correlations between weight loss and skeletal development or sexual maturation were observed. CONCLUSIONS: Approximately one-third of children treated with zonisamide experienced ≥ 5% weight loss. Weight loss was most apparent in children with high baseline BMI values and did not appear to be associated with any consistent effects on growth and development.

Prenatal ethanol exposure differentially affects hippocampal neurogenesis in the adolescent and aged brain.

Exposure to ethanol in utero is associated with a myriad of sequelae for the offspring. Some of these effects are morphological in nature and noticeable from birth, while others involve more subtle changes to the brain that only become apparent later in life when the individuals are challenged cognitively. One brain structure that shows both functional and structural deficits following prenatal ethanol exposure is the hippocampus. The hippocampus is composed of two interlocking gyri, the cornu ammonis (CA) and the dentate gyrus (DG), and they are differentially affected by prenatal ethanol exposure. The CA shows a more consistent loss in neuronal numbers, with different ethanol exposure paradigms, than the DG, which in contrast shows more pronounced and consistent deficits in synaptic plasticity. In this study we show that significant deficits in adult hippocampal neurogenesis are apparent in aged animals following prenatal ethanol exposure. Deficits in hippocampal neurogenesis were not apparent in younger animals. Surprisingly, even when ethanol exposure occurred in conjunction with maternal stress, deficits in neurogenesis did not occur at this young age, suggesting that the capacity for neurogenesis is highly conserved early in life. These findings are unique in that they demonstrate for the first time that deficits in neurogenesis associated with prenatal ethanol consumption appear later in life.

Prenatal ethanol exposure has sex-specific effects on hippocampal long-term potentiation.

Alcohol consumption during pregnancy is deleterious to the developing brain of the fetus and leads to persistent deficits in adulthood. Long-term potentiation (LTP) is a biological model for learning and memory processes and previous evidence has shown that prenatal ethanol exposure (PNEE) affects LTP in a sex specific manner during adolescence. The objective of this study was to determine if there are sex specific differences in adult animals and to elucidate the underlying molecular mechanisms that contribute to these differences. Pregnant Sprague-Dawley dams were assigned to either; liquid ethanol, pair-fed or standard chow diet. In vivo electrophysiology was performed in the hippocampal dentate gyrus (DG) of adult offspring. LTP was induced by administering 400 Hz stimuli. Western blot analysis for glutamine synthetase (GS) and glutamate decarboxylase from tissue of the DG indicated that GS expression was increased following PNEE. Surprisingly, adult females did not show any deficit in N-methyl-D-aspartate (NMDA)-dependent LTP after PNEE. In contrast, males showed a 40% reduction in LTP. It was indicated that glutamine synthetase expression was increased in PNEE females, suggesting that altered excitatory neurotransmitter replenishment may serve as a compensatory mechanism. Ovariectomizing females did not influence LTP in control or PNEE animals, suggesting that circulating estradiol levels do not play a major role in maintaining LTP levels in PNEE females. These results demonstrate the sexually dimorphic effects of PNEE on the ability for the adult brain to elicit LTP in the DG. The mechanisms for these effects are not fully understood, but an increase in glutamine synthetase in females may underlie this phenomenon.

Liquid diets reduce cell proliferation but not neurogenesis in the adult rat hippocampus.

Neurogenesis continues to occur in restricted regions of the brain throughout adulthood and can be modulated by dietary factors. Liquid or "soft" diets are commonly used for the administration of drugs in experimental models of disease, making it critical to determine whether dietary composition itself can affect neurogenesis. In this study Sprague-Dawley rats were fed either a liquid or a solid diet of identical composition from weaning until young adulthood. No differences in neuronal differentiation and survival of newly born cells were observed between rats that were fed a liquid diet and those that received a solid diet. However, a significant reduction in hippocampal cell proliferation was observed in the liquid diet-fed group, as assessed by the expression of two endogenous proliferation markers, Ki67 and proliferating cell nuclear antigen (PCNA). The method of feeding did not alter the basal function of the hypothalamic-pituitary-adrenal (HPA) axis in these animals, as no changes in circulating levels of corticosterone (CORT) were detected between liquid and solid diet-fed groups. There was also a significant reduction in cellular proliferation in the hypothalamus of liquid diet-fed rats, a brain region known to be involved in feeding-related behaviors. These findings indicate that liquid diets themselves can directly impact rates of cellular proliferation, but this does not seem to impact levels of overall neurogenesis in the adult brain.

Safety and tolerability of zonisamide in elderly patients with epilepsy.

OBJECTIVES: To assess the safety/tolerability of zonisamide in elderly patients. MATERIALS & METHODS: A pooled analysis of clinical study data from elderly (≥65 years) patients receiving add-on/monotherapy zonisamide for partial seizures was compared with pooled adult (18-65 years) study data. Assessments included treatment-emergent adverse events (TEAEs), clinical laboratory parameters and weight change. RESULTS: Data were analyzed from 95 elderly and 1389 adult patients. Incidence of total TEAEs was similar (elderly, 78/95 [82%] vs adult, 1165/1389 [84%]); but lower in elderly versus adult patients for treatment-related TEAEs (53/95 [56%] vs 1010/1389 [73%]), severe TEAEs (11/95 [12%] vs 289/1389 [21%]), serious TEAEs (12/95 [13%] vs 230/1389 [17%]) and TEAEs leading to withdrawal (17/95 [18%] vs 312/1389 [23%]). Most TEAEs were of mild-to-moderate intensity. TEAEs reported more frequently by elderly versus adult patients included fatigue (11/95 [12%] vs 135/1389 [10%]), nasopharyngitis (8/95 [8%] vs 100/1389 [7%]), constipation (7/95 [7%] vs 67/1389 [5%]) and pruritus (6/95 [6%] vs 29/1389 [2%]). The only serious TEAEs reported by ≥2% of elderly patients were 'convulsions' (4/95 [4%] vs 49/1389 [4%]). Three elderly patients died; one death was considered treatment-related. TEAEs leading to discontinuation of ≥2% of elderly patients were dizziness (4/95 [4%]), headache (2/95 [2%]), somnolence (2/95 [2%]) and confusional state (2/95 [2%]). For elderly patients, there were minimal changes in clinical laboratory parameters, no reports of respiratory alkalosis or metabolic acidosis and no significant weight changes. CONCLUSIONS: Zonisamide demonstrated a favourable safety/tolerability profile in elderly patients. No new or unexpected safety findings were identified.

Spontaneous rupture of the tibialis anterior tendon: a case report and literature review.

Spontaneous rupture of the tibialis anterior tendon is uncommon. This article presents a case report in which spontaneous rupture of the tibialis anterior tendon occurred secondary to a gouty tophaceous deposit within the tendon. This report adds to the list of pathological conditions that should be considered in closed spontaneous rupture of the tibialis anterior tendon.

Production and characterization of monoclonal antibodies to ARVCF.

We have generated the first monoclonal antibodies (MAbs) to Armadillo repeat gene deleted in velo-cardiofacial syndrome (ARVCF), a recently identified Armadillo repeat-containing protein closely related to the catenin p120ctn. Six ARVCF-specific MAbs were characterized for isotype, species cross-reactivity, and utility in assays including immunofluorescence, immunoprecipitation, and Western blotting. All six antibodies were isotyped as IgG1 and several cross-reacted with ARVCF from a variety of species including human, rat, dog, and monkey, but not mouse. Importantly, none of the ARVCF MAbs cross-reacted with p120ctn, despite the high homology between these proteins. MAbs 3B2 and 4B1 were consistently the best in all applications and will provide valuable tools for further study of the role of ARVCF in cells.

ETO, a target of t(8;21) in acute leukemia, interacts with the N-CoR and mSin3 corepressors.

t(8;21) is one of the most frequent translocations associated with acute myeloid leukemia. It produces a chimeric protein, acute myeloid leukemia-1 (AML-1)-eight-twenty-one (ETO), that contains the amino-terminal DNA binding domain of the AML-1 transcriptional regulator fused to nearly all of ETO. Here we demonstrate that ETO interacts with the nuclear receptor corepressor N-CoR, the mSin3 corepressors, and histone deacetylases. Endogenous ETO also cosediments on sucrose gradients with mSin3A, N-CoR, and histone deacetylases, suggesting that it is a component of one or more corepressor complexes. Deletion mutagenesis indicates that ETO interacts with mSin3A independently of its association with N-CoR. Single amino acid mutations that impair the ability of ETO to interact with the central portion of N-CoR affect the ability of the t(8;21) fusion protein to repress transcription. Finally, AML-1/ETO associates with histone deacetylase activity and a histone deacetylase inhibitor impairs the ability of the fusion protein to repress transcription. Thus, t(8;21) fuses a component of a corepressor complex to AML-1 to repress transcription.

William A. Hammond, the dynamograph, and bogus neurologic testimony in old New York.

April 25, 1870, court of General Sessions, New York City, Doctor William A. Hammond, neurologist and former Surgeon General of the United States Army, testified at the trial of his patient Daniel McFarland. McFarland had fatally wounded famous journalist Albert Richardson in November of 1869. Dr. Hammond said McFarland suffered from temporary insanity due to cerebral congestion from over use of the brain. Hammond told the jury he had, "devoted the last five years of his professional life exclusively to the study of the mind", and opined that the evidence of cerebral congestion was profound: McFarland's head was hot, and his carotid throbbed. The proof came from the test with the dynamograph machine: McFarland could not keep a pencil still to trace a straight line in the center of a moving piece of paper. The dynamograph, Dr. Hammond assured the jury, measured the power of a man over his will and thus provided "full and decided evidence" there can be no doubt that McFarland "could not control his will". What were the motivations behind the testimony of this famous expert witness? Did bogus neurologic testimony exist in old New York over a century before our time?

Crystal structure of the p27Kip1 cyclin-dependent-kinase inhibitor bound to the cyclin A-Cdk2 complex.

The crystal structure of the human p27Kip1 kinase inhibitory domain bound to the phosphorylated cyclin A-cyclin-dependent kinase 2 (Cdk2) complex has been determined at 2.3 angstrom. p27Kip1 binds the complex as an extended structure interacting with both cyclin A and Cdk2. On cyclin A, it binds in a groove formed by conserved cyclin box residues. On Cdk2, it binds and rearranges the amino-terminal lobe and also inserts into the catalytic cleft, mimicking ATP.

Both RNA-binding domains in heterogenous nuclear ribonucleoprotein A1 contribute toward single-stranded-RNA binding.

Heterogenous nuclear ribonucleoproteins (hnRNPs) such as hnRNP A1 are tightly associated with heterogenous nuclear RNAs (hnRNAs) within eukaryotic nuclei and are thought to be involved in hnRNA processing and splice site selection. The NH2-terminal two-thirds of hnRNP A1 contains two 92-amino acid RNA binding domains (RBDs) that are arranged in tandem and are more than 30% homologous with each other. Following this region is a flexible glycine-rich COOH-terminal domain. We have studied the nucleic acid binding properties of the two isolated RBDs (residues 1-92 and 93-184, respectively) and of A1 fragments corresponding to residues 1-184 and 1-196 (i.e., the latter fragment is called UP1) in order to evaluate their relative contributions to A1 binding. We have determined that the individual RBDs of A1 bind poly[r(epsilon A)], a fluorescent single-stranded RNA (ssRNA), with a surprisingly low apparent association constant of only 1.5 x 10(4) M-1 (1-92) and 4.5 x 10(4) M-1 (93-184), respectively. We hypothesize that this low affinity represents a basal level of binding that is common to most RBD-containing proteins. Oligonucleotide binding studies suggest the interaction site size for the 93-184 fragment is approximately 4 nucleotides or less and salt sensitivity studies indicate that only about 27% of the free energy of binding of this RBD derives from ionic interactions. Since the affinity of the 1-184 fragment is at least 10-fold above that of either of its component RBDs, both must contribute to binding. This conclusion is further supported by the increased occluded site size of 1-184 (n = 14 +/- 2), as compared to its 93-184 RBD (n = 6 +/- 1), and by the biphasic binding that was observed for the UP1:poly(U) interaction at pH 6.0. Our finding that the affinity of the 1-184 fragment is 1000-fold less than the product of the affinities of its 1-92 and 93-184 RBDs is consistent with these domains being joined by a flexible linker. By comparing the affinities of the 1-184 fragment with that for A1, we conclude that together the two RBDs in A1 account for only 53% of the free energy of A1 binding. Comparative binding studies with UP1 demonstrate that the short region spanning residues 185-->195 represents an important determinant of the binding affinity of A1 and, since this region contains a site of dimethylation, it may provide a mechanism for regulating the affinity of A1 for specific nucleic acid targets.