The role of central orexin in the sympathetic control of interscapular brown adipose tissue (iBAT) thermogenesis has been established in rodents. Stimulatory doses of caffeine activate orexin ...positive neurons in the lateral hypothalamus, a region of the brain implicated in stimulating BAT thermogenesis. This study tests the hypothesis that central administration of caffeine is sufficient to activate BAT. Low doses of caffeine administered either systemically (intravenous IV; 10 mg/kg) and centrally (intracerebroventricular ICV; 5-10 μg) increases BAT thermogenesis, in anaesthetised (1.5 g/kg urethane, IV) free breathing male rats. Cardiovascular function was monitored via an indwelling intra-arterial cannula and exhibited no response to the caffeine. Core temperature did not significantly differ after administration of caffeine via either route of administration. Caffeine administered both IV and ICV increased neuronal activity, as measured by c-Fos-immunoreactivity within subregions of the hypothalamic area, previously implicated in regulating BAT thermogenesis. Significantly, there appears to be no neural anxiety response to the low dose of caffeine as indicated by no change in activity in the basolateral amygdala. Having measured the physiological correlate of thermogenesis (heat production) we have not measured indirect molecular correlates of BAT activation. Nevertheless, our results demonstrate that caffeine, at stimulatory doses, acting via the central nervous system can increase thermogenesis, without adverse cardio-dynamic impact.
A Civilian's Suggestions for a Technical Reserve for the Army Haskins, Caryl D.; Abbot, F. V.; Wells, W. F. ...
Professional memoirs, Corps of Engineers, United States Army and Engineer Department at Large,
07/1911, Letnik:
3, Številka:
11
Journal Article
Centrally administered estrogen can increase sympathetic nerve activity to brown adipose tissue, resulting in thermogenesis. The central thermogenic effects of estrogen have not been investigated in ...males. Therefore, this study sought to investigate the effects of peripherally and centrally administered estrogen on thermogenesis, heart rate and mean arterial pressure in male rats. Thermogenesis was assessed by monitoring brown adipose tissue temperature.
Peripherally administered estrogen elicited no significant effect on brown adipose tissue temperature, heart rate or mean arterial pressure. Centrally administered estrogen elicited a coincident increase in both brown adipose tissue and core temperature. Centrally administered estrogen also resulted in a decrease in mean arterial pressure but had no effect on heart rate. With the present data it is not possible to elucidate whether changes in temperature were the result of thermogenic or thermoregulatory mechanisms.
Sulfur assimilation is an evolutionarily conserved pathway that plays an essential role in cellular and metabolic processes, including sulfation, amino acid biosynthesis, and organismal development. ...We report that loss of a key enzymatic component of the pathway, bisphosphate 3′-nucleotidase (Bpnt1), in mice, both whole animal and intestine-specific, leads to iron-deficiency anemia. Analysis of mutant enterocytes demonstrates that modulation of their substrate 3′-phosphoadenosine 5′-phosphate (PAP) influences levels of key iron homeostasis factors involved in dietary iron reduction, import and transport, that in part mimic those reported for the loss of hypoxic-induced transcription factor, HIF-2α. Our studies define a genetic basis for iron-deficiency anemia, a molecular approach for rescuing loss of nucleotidase function, and an unanticipated link between nucleotide hydrolysis in the sulfur assimilation pathway and iron homeostasis.
•Intra-nasal magnetic delivery was performed to guide magnetic rods to the brain.•Multi-segmented micro magnetic rods were used for magnetic delivery.•Pulling and spinning magnetic fields were ...applied simultaneously.•Particles were transported by translational and rotational motions.•Pull and drill rods can greatly improve the transport of drugs to the brain.
Getting drugs deep into the brain to treat cancers, neurological disease, and behavioral disorders is challenging. In this work, we tried to improve the efficiency of intra-nasal transport into the brain via the cribriform plate using magnetic particles. We and others have used magnetic particles for delivering heat, drugs, and genes. We performed experiments with mouse cadavers that received 250-nm-wide intra-nasal magnetic rods intra-nasally under different combinations of magnetic fields. We found that the application of helical dynamic gradients to the particles (i.e., both rotational and linear) improved transport from the nose into the brain, as compared to linear magnetic gradients alone. On histological examination, no tracks were observed to suggest significant damage to the brain during the transport process. We are currently building a system for testing with live animals, with eventual proposed application to humans.
Electropermanent magnets for variable-field NMR Ropp, Chad; Chen, Cheng; Greer, Mason ...
Journal of magnetic resonance (1997),
June 2019, 2019-06-00, 20190601, Letnik:
303
Journal Article
Recenzirano
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•A dynamically tunable B0 field to perform variable-field NMR.•Offer both the advantages of a permanent magnet and an electromagnet.•Full theoretical estimation of effective SNR for ...CPMG-like measurement.•Alternative to low-cost fast field-cycling NMR system.
In this work, a dynamically tunable B0 field is used to perform variable-field NMR. The system consists of an array of electropermanent AlNiCo-5 magnets whose magnetizations are individually programmed using pulse-power control. This design allows the field strength to be varied for field-dispersion measurements. An ultra-broadband front-end is utilized that maintains efficient power transmission over a broad range of frequencies for robust operation without probe tuning. We perform T1-T2 correlation measurements at various B0 field strengths (0.5–2 MHz) and demonstrate discrimination of different dairy products. We observe variation in the frequency dependence of the proton spin–lattice relaxation for the different products as a function of the degree of protein hydration. This variable-field technique provides a low-cost alternative to fast field-cycling NMR and could open possibilities for novel contrast measurements and spatial encoding in magnetic resonance imaging.
Soft, untethered microrobots composed of biocompatible materials for completing micromanipulation and drug delivery tasks in lab-on-a-chip and medical scenarios are currently being developed. ...Alginate holds significant potential in medical microrobotics due to its biocompatibility, biodegradability, and drug encapsulation capabilities. Here, we describe the synthesis of MANiACs-Magnetically Aligned Nanorods in Alginate Capsules-for use as untethered microrobotic surface tumblers, demonstrating magnetically guided lateral tumbling via rotating magnetic fields. MANiAC translation is demonstrated on tissue surfaces as well as inclined slopes. These alginate microrobots are capable of manipulating objects over millimeter-scale distances. Finally, we demonstrate payload release capabilities of MANiACs during translational tumbling motion.
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