Identifying and reverting the adverse effects of white matter hyperintensities on cortical surface analyses

The Human Connectome Project (HCP)-style surface-based brain MRI analysis is a powerful technique that allows precise mapping of the cerebral cortex. However, the strength of its surface-based analysis has not yet been tested in the older population that often presents with white matter hyperintensities (WMHs) on T2-weighted (T2w) MRI (hypointensities on T1w MRI). We investigated T1-weighted (T1w) and T2w structural MRI in 43 healthy middle-aged to old participants. Juxtacortical WMHs were often misclassified by the default HCP pipeline as parts of the gray matter in T1w MRI, leading to incorrect estimation of the cortical surfaces and cortical metrics. To revert the adverse effects of juxtacortical WMHs, we incorporated the Brain Intensity AbNormality Classification Algorithm into the HCP pipeline (proposed pipeline). Blinded radiologists performed stereological quality control (QC) and found a decrease in the estimation errors in the proposed pipeline. The superior performance of the proposed pipeline was confirmed using an originally-developed automated surface QC based on a large database. Here we showed the detrimental effects of juxtacortical WMHs for estimating cortical surfaces and related metrics and proposed a possible solution for this problem. The present knowledge and methodology should help researchers identify adequate cortical surface biomarkers for aging and age-related neuropsychiatric disorders.

URAT1-selective inhibition ameliorates insulin resistance by attenuating diet-induced hepatic steatosis and BAT whitening in mice

Background

Accumulating evidence suggests that high uric acid is strongly associated with obesity and metabolic syndrome and drives the development of non-alcoholic fatty liver disease (NAFLD) and insulin resistance. Although urate transporter-1 (URAT1), which is primarily expressed in the kidney, plays a critical role in the development of hyperuricemia, its pathophysiological implication in NAFLD and insulin resistance remains unclear.

Objectives

We hypothesizes that URAT1 plays an important role in obesity-induced metabolic disorders, and URAT1-selective inhibitor treatment ameliorates systemic insulin resistance, NAFLD and adipose tissue dysfunction using diet-induced obese mice.

Methods

Mice fed a high-fat diet (HFD) for 16 to 18 weeks or a normal-fat diet (NFD) were treated with or without a novel oral URAT1-selective inhibitor (dotinurad [50 mg/kg/day]) for another 4 weeks.

Results

Dotinurad administration significantly ameliorated HFD-induced obesity and insulin resistance. We found that URAT1 was also expressed in the liver and brown adipose tissue (BAT) other than kidney. HFD markedly induced NAFLD, which was characterized by severe hepatic steatosis, as well as the elevation of serum ALT activity and tissue inflammatory cytokine genes (Ccl2 and TNFα), all of which were attenuated by dotinurad. Likewise, HFD significantly increased URAT1 expression in BAT, resulting in the lipid accumulation (whitening of BAT) and increased production of tissue reactive oxygen species, which were reduced by dotinurad via UCP1 activation.

Conclusions

A novel URAT1-selective inhibitor, dotinurad, ameliorates insulin resistance by attenuating hepatic steatosis and promoting rebrowning of lipid-rich BAT in HFD-induced obese mice. URAT1 serves as a key regulator of the pathophysiology of metabolic syndrome, and may be a new therapeutic target for insulin-resistant individuals, particularly those with concomitant NAFLD.

Funding Acknowledgement

Type of funding sources: None.

Unravelling the dissolution mechanism of polyphosphate glasses by 31P NMR spectroscopy: ligand competition and reactivity of intermediate complexes

Phosphate glass dissolution can be tailored via compositional and subsequent structural changes, which is of interest for biomedical applications such as therapeutic ion delivery. Here, solid-state ³¹P nuclear magnetic resonance characterisation of 45P₂O₅-xCaO - (55 -x)Na₂O glasses was correlated with dissolution studies using time-dependent liquid ³¹P NMR spectroscopy and quantitative chemical analysis. Glasses dissolved congruently in aqueous media, and the first dissolution stage was the hydration of phosphate chains. In deionised water and Tris buffer (pH₀ 7.4 or 7.9), trimetaphosphate rings and orthophosphates were the predominant species in solution, indicating relatively fast degradation. By contrast, long phosphate chains were identified in EDTA (pH₀ 10.0). Besides pH differences, coordination of phosphate species by metal cations appears to play a catalytic role in the hydrolysis mechanism via turning phosphorus atoms into suitable electrophiles for the subsequent nucleophilic attack by water. Hydrolysis rates were proportional to phosphate complex stability, with stronger complexes for chains than for rings. A competition between solvent and phosphate species for the metal ion occurred in the order EDTA > Tris > deionised water.

Xanthine oxidase inhibition attenuates doxorubicin-induced cardiotoxicity in mice

Background

Accumulating evidence suggests that high serum uric acid (UA) is associated with left ventricular (LV) dysfunction. Although xanthine oxidase (XO) activation is a critical regulatory mechanism of the terminal step in ATP and purine degradation, the pathophysiological role of cardiac tissue XO in LV dysfunction remains unclear.

Objectives

We hypothesized that cardiac XO is activated in doxorubicin-induced LV dysfunction, and XO inhibitors ameliorate LV function by inhibiting cell death signals as well as by modifying cardiac purine metabolism.

Methods

Either doxorubicin (10 mg/kg) or vehicle was intraperitonially administered in a single injection to ICR mice. Mice were treated with or without oral XO inhibitors (febuxostat 3 mg/kg/day or topiroxostat 5 mg/kg/day) for 8 days starting 24 hours before doxorubicin-injection. The LV function was assessed by echocardiography at day 6 and by ex vivo heart perfusion at day 7.

Results

Cardiac tissue XO activity measured by a highly sensitive assay with liquid chromatography/mass spectrometry (n=8 each) and cardiac UA content (n=3–6) were significantly increased in doxorubicin-treated mice at day 7 and dramatically reduced by XO inhibitors. Accordingly, XO inhibitors substantially improved LV ejection fraction (n=8 each) and LV developed pressure (n=9 each) that had been impaired by doxorubicin administration. Intriguingly, the expression of GPX4, a negative regulator of ferroptosis, was decreased in doxorubicin-treated hearts but improved by XO inhibitors (n=6 each). Furthermore, metabolome analyses revealed an enhanced purine metabolism in doxorubicin-treated hearts, and XO inhibitors suppressed the serial metabolic reaction of hypoxanthine–xanthine–UA.

Conclusions

Doxorubicin administration induces cardiac tissue XO activation associated with an impaired LV function. XO inhibition attenuates the doxorubicin-induced cardiotoxicity partly through an anti-ferroptotic effect and the conservation of tissue ATP levels by modulating purine metabolism. The present study suggests that pharmacological XO inhibition represents a potential therapeutic strategy for the treatment of doxorubicin-induced cardiotoxicity.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was supported in part by grants-in-aid for Ministry of Education Culture, Sports, Science and Technology.

Direct Current Electrical Stimulation of Acupuncture Needles for Peripheral Nerve Regeneration: An Exploratory Case Series

Objective

To examine the therapeutic effect of a novel therapeutic method based on electroacupuncture with intermittent direct current (DCEA) and associated adverse events in patients with peripheral nerve damage and a poor clinical prognosis.

Methods

In seven older patients with peripheral nerve damage (neurapraxia 2, axonotmesis 4, neuromesis 1), an acupuncture needle connected to an anode electrode was inserted proximal to the site of the injury along the route of the nerve, while the cathode electrode was inserted into the innervated muscle, and DCEA was performed (100 Hz for 20 min, weekly). Muscular paralysis was evaluated weekly with manual muscle testing, the active range of motion of joints related to the muscular paralysis and, when necessary, needle electromyography. Adverse events were also recorded during the course of the treatment.

Results

Complete functional recovery was observed in the two cases with neurapraxia and two with axonotmesis, while one axonotmesis case achieved improvement and the other showed reinnervation potential without functional recovery. No improvement was observed in the neurotmesis case. Pigmentation of the skin where the anode needle was inserted occurred in three cases. Although there was no definite causal link, one case showed excessive formation and resorption of bone in the area close to the cathode needle site.

Discussion

Accelerated nerve regeneration caused by DCEA may contribute to recovery. The skin pigmentation and callus formation suggest that the shape of the anode electrode, current intensity and other factors should be examined to establish a safer treatment method.

[Low-dose perampanel improved cortical myoclonus and basophobia in a patient with Unverricht-Lundborg disease: a case report]

We report a 32-year-old female who presented myoclonus and generalized tonic-clonic seizure since she was 9 year-old. Thereafter, she was diagnosed as Unverricht-Lundborg disease by gene analysis. Although the epileptic seizures were controlled by multiple antiepileptic drugs, her cortical myoclonus remained intractable, which severely interfered her activity of daily living. On admission to our hospital, she presented mild cognitive impairment, dysarthria, severe postural and action myoclonus in all the limbs, severe impairment of coordinative movements, inability of standing and walking by herself, and severe basophobia. After administration of perampanel, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist, with initial dose of 1 mg/day, and then 16 days later it was increased up to 2 mg/day, the myoclonus dramatically improved and the basophobia also lessened about in 30 days since it started. Moreover, abnormally enlarged amplitudes of short latency somatosensory evoked potentials by median nerve stimulation decreased, which suggested the reduction of abnormal cortical hyperexcitability mainly in the primary sensori-motor cortices. We presented that perampanel is the effective drug for treating the refractory cortical myoclonus and basophobia even with small dosage.

Effects of aging on basement membrane of the soleus muscle during recovery following disuse atrophy in rats

Aging is known to lead to the impaired recovery of muscle after disuse as well as the increased susceptibility of the muscle to damage. Here, we show that, in the older rats, reloading after disuse atrophy, causes the damage of the muscle fibers and the basement membrane (BM) that structurally support the muscle fibers. Male Wistar rats of 3-(young) and 20-(older) months of age were subjected to hindlimb-unloading for 2weeks followed by reloading for a week. In the older rats, the soleus muscles showed necrosis and central nuclei fiber indicating the regeneration of muscle fibers. Furthermore, ectopic immunoreactivity of collagen IV, a major component of the BM, remained mostly associated with the necrotic appearance, suggesting that the older rats were impaired with the ability of repairing the damaged BM. Further, after unloading and reloading, the older rats did not show a significant alteration, although the young rats showed clear response of Col4a1 and Col4a2 genes, both coding for collagen IV. In addition, during the recovery phase, the young rats showed increase in the amount of Hsp47 and Sparc mRNA, which are protein folding-related factor genes, while the older rats did not show any significant variation. Taken together, our findings suggest that the atrophic muscle fibers of the older rats induced by unloading were vulnerable to the weight loading, and that attenuated reactivity of the BM-synthesizing fibroblast to gravity contributes to the fragility of muscle fibers in the older animals.

Role of alpha adrenoceptors in the nucleus accumbens in the control of accumbal noradrenaline efflux: a microdialysis study with freely moving rats

Microdialysis technique was used to study the effects of the locally applied alpha adrenoceptor agonist phenylephrine and antagonist phentolamine on the basal noradrenaline efflux as well as on the noradrenaline uptake inhibitor desipramine-elicited noradrenaline efflux in the nucleus accumbens (NAc) of freely moving rats. Tetrodotoxin reduced basal noradrenaline efflux by 72%, whereas desipramine increased it by 204%. Phenylephrine reduced the basal noradrenaline efflux by 32% and phentolamine blocked this effect. Phentolamine elevated the basal noradrenaline efflux by 150% and phenylephrine counteracted this effect. The desipramine-elicited noradrenaline efflux was not affected by phenylephrine, but enhanced by phentolamine. Desipramine counteracted the effects of phenylephrine and potentiated those of phentolamine. These results indicate that the accumbal noradrenaline efflux is under inhibitory control of alpha adrenoceptors that are suggested to be presynaptically located on adrenergic nerve terminals in the NAc. Furthermore, this study suggests that the conformational state of alpha adrenoceptors varies across the available amount of noradrenaline. The clinical impact of these data is discussed.

Pharmacological study of BRS, a new bicarbonated Ringer's solution, in haemorrhagic shock dogs

BACKGROUND AND OBJECTIVES

Sodium bicarbonate is the most physiological alkalinizing agent. The effect of a new bicarbonated Ringer's solution (BRS) containing Mg2+, on metabolic acidosis and serum magnesium abnormality were evaluated and compared with those of acetated Ringer's (ARS), lactated Ringer's (LRS) and Ringer's (RS) solutions in an experimental haemorrhagic shock model with dogs.

METHODS

Animals were randomly divided into six groups (n = 6 in each group), a sham-operated group, an operated group without infusion, and 4 operated groups with infusion (BRS, ARS, LRS and RS groups). Each RS was intravenously administered at 60 mL kg(-1) h(-1) for 1.5 h. Arterial blood gases, plasma electrolytes and cardiovascular parameters were analysed.

RESULTS

BRS significantly improved blood base excess values, which were decreased by blood-letting, faster and more markedly than did LRS and RS (BRS--6.3 +/- 0.5 mEq L(-1); LRS--9.2 +/- 1.1 mEq L(-1); RS--12.4 +/- 1.0 mEq L(-1) at the end of infusion). The alkalinizing effect of BRS tended to be better than that of ARS but not significantly so. The serum Mg2+ concentration was well-maintained by BRS as compared to other RS (BRS 1.5 +/- 0.0 mgdL(-1); ARS 1.2 +/- 0.0mgdL(-1); LRS 1.1 +/- 0.0mgdL(-1); RS 1.3 +/- 0.1 mgdL(-1), at the end of infusion).

CONCLUSIONS

These results suggest that BRS is a suitable perioperative solution for metabolic acidosis and serum electrolyte balance among RS tested.

Anaesthesia and circulating blood volume

BACKGROUND AND OBJECTIVE

The exact change in circulating blood volume (BV) during general anaesthesia is still unknown because there is no standard method of evaluating BV. We evaluated the changes in BV by general anaesthesia using simple and easy estimation methods.

METHODS

Fourteen patients scheduled for minor surgery under general anaesthesia were enrolled. Propofol and vecuronium bromide were used for the induction of anaesthesia, and anaesthesia was maintained with sevoflurane and nitrous oxide. Haematocrit (Hct), total protein concentration (TP), as well as colloid osmotic pressure (COP) measured using a colloid osmometer, were determined before anaesthesia, and 30, 60 and 90 min after the induction of general anaesthesia. BV was calculated using Allen's formula and the changes in Hct, TP and COP. The estimated BV was compared with directly measured BV using indocyanine green dilution method (BV(ICG)).

RESULTS

Hct, TP and COP significantly decreased after the induction of anaesthesia (Hct: 42.1-39.4%; TP: 7.3-6.9 g dL(-1); COP: 23-19 mmHg). The calculated BV as well as BV(ICG) significantly increased after induction of anaesthesia (calculated by COP: 4.13-5.03 L; BV(ICG): 4.54-5.56 L). The change rate in BV calculated by the change of COP was larger than other calculated BVs, and was approximated to the change rate in BV(ICG). After emergence from anaesthesia, all values tended to return to baseline.

CONCLUSIONS

General anaesthesia increases BV. The value of BV calculated from the change in COP was most changeable.

Interactions among mu- and delta-opioid receptors, especially putative delta1- and delta2-opioid receptors, promote dopamine release in the nucleus accumbens

The effect of interactions among mu- and delta-opioid receptors, especially the putative delta(1)- and delta(2)-opioid receptors, in the nucleus accumbens on accumbal dopamine release was investigated in awake rats by in vivo brain microdialysis. In agreement with previous studies, perfusion of the nucleus accumbens with the mu-, delta(1)- and delta(2)-opioid receptor agonists [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin (DAMGO), [D-Pen(2,5)]-enkephalin (DPDPE) and [D-Ser(2)]Leu-enkephalin-Thr(6), respectively, significantly enhanced the extracellular amount of accumbal dopamine in a dose-related manner (5.0 nmol and 50.0 nmol). However, the highest concentration tested (50.0 nmol) of DAMGO induced a biphasic effect, i.e. a rapid onset increase lasting for 75 min followed by a slower onset gradual and prolonged increase. The mu-opioid receptor antagonist D-Phe-Cys-Tyr-d-Trp-Orn-Thr-Phe-Thr-NH(2) (0.15 nmol) primarily reduced the DAMGO-induced second component. The delta(1)-opioid receptor antagonist (E)-7-benzylidenenaltrexone (0.15 nmol) significantly reduced the first component and abolished the second component induced by DAMGO, while the delta(2)-opioid receptor antagonist naltriben (1.5 nmol) significantly reduced only the first component. The DPDPE (50.0 nmol)-induced dopamine increase was almost completely abolished by (E)-7-benzylidenenaltrexone, but only partially reduced by D-Phe-Cys-Tyr-d-Trp-Orn-Thr-Phe-Thr-NH(2) and naltriben. The [D-Ser(2)]Leu-enkephalin-Thr(6) (50.0 nmol)-induced dopamine increase was almost completely abolished by naltriben, but not at all by D-Phe-Cys-Tyr-d-Trp-Orn-Thr-Phe-Thr-NH(2) and (E)-7-benzylidenenaltrexone. The non-selective opioid receptor antagonist naloxone (0.75 and 1.5 nmol) dose-dependently reduced the effects of DAMGO, DPDPE and [D-Ser(2)]Leu-enkephalin-Thr(6) but only to about 10-25% of the control values. Moreover, perfusion with the sodium channel blocker tetrodotoxin (0.1 nmol) reduced the DAMGO-induced dopamine increase by 75%, while it almost completely abolished the increase induced by DPDPE or [D-Ser(2)]Leu-enkephalin-Thr(6). The results show that stimulation of mu-opioid receptors or, to a lesser degree, delta(1)-opioid receptors results in a large naloxone-sensitive increase and a small naloxone-insensitive increase of extracellular dopamine. It is suggested that the naloxone-insensitive component is also tetrodotoxin-insensitive. Furthermore, it is hypothesized that stimulation of mu-opioid receptors activates delta(1)-receptors, which in turn activate delta(2)-opioid receptors, thereby giving rise to a rapid onset increase of extracellular dopamine. In addition, it is hypothesized that stimulation of another group of mu-opioid receptors activates a second group of delta(1)-opioid receptors that is not coupled to delta(2)-opioid receptors and mediates a slow onset increase of extracellular dopamine. Finally, it is suggested that stimulation of delta(1)- or delta(2)-opioid receptors inhibits mu-opioid receptors involved in the slow onset increase in extracellular dopamine, whereas stimulation of delta(1)-, but not delta(2)-, opioid receptors is suggested to activate mu-opioid receptors involved in the rapid increase in extracellular dopamine.

Effects of NMDA and MK-801 injected into the substantia nigra pars reticulata on jaw movements evoked by dopamine D1/D2 receptor stimulation in the ventrolateral striatum: Studies in freely moving rats

The effects of NMDA and MK-801 injected into the substantia nigra pars reticulata on jaw movements evoked by dopamine D1/D2 receptor stimulation in the ventrolateral striatum were examined in freely moving rats, by using a magnet-sensing system combined with intracerebral drug microinjection technique. Bilateral injections of a mixture of SKF 82958 (5 microg) and quinpirole (10 microg), agonist at dopamine D1 and D2 receptors respectively, into the ventrolateral striatum elicited repetitive jaw movements. Bilateral injections of NMDA (0.01 and 0.05 microg/0.2 microl in each side) into the substantia nigra pars reticulata, which alone did not produce jaw movements, reduced the repetitive jaw movements evoked by the dopamine D1/D2 receptor agonist mixture in a dose-dependent manner. Injection of the non-competitive NMDA receptor antagonist, MK-801 (0.1 and 0.5 microg/0.2 microl in each side), into the substantia nigra pars reticulata, which alone did not produce jaw movements, prevented the dopaminergic jaw movements in a dose-dependent manner. Moreover, other behaviors such as grooming, rearing, yawning, vacuous chewing, and locomotor activity that occurred after injections of the dopamine receptor agonist mixture were not significantly altered by the bilateral injections of NMDA or MK-801 into the substantia nigra pars reticulata. Given our previous results showing that both agonist and antagonist of GABA(A) receptors injected into the substantia nigra pars reticulata inhibit the jaw movements elicited by dopamine D1/D2 receptor stimulation in the ventrolateral striatum, the present results suggest that there are complex functional interactions between NMDA and GABA(A) receptors within the substantia nigra pars reticulata that may be responsible for the common profiles in the effects of NMDA and GABA(A) receptor agents.

The angiotensin II receptor blocker candesartan improves survival and mesenteric perfusion in an acute porcine endotoxin model

BACKGROUND

Blockade of the angiotensin II type 1 (AT1) receptor has been demonstrated to ameliorate splanchnic hypoperfusion in acute experimental circulatory failure. This study focused on hemodynamic changes and survival in pigs treated with AT1 blockade prior to or during acute endotoxinemia.

METHODS

Escherichia coli lipopolysaccharide endotoxin was infused in anesthetized and mechanically ventilated pigs. Systemic, renal, mesenteric and jejunal mucosal perfusion as well as systemic oxygen and acid-base balance were monitored. The selective AT1 receptor blocker candesartan was administered prior to as well as during endotoxinemia. Control animals received the saline vehicle.

RESULTS

Pre-treatment with candesartan resulted in higher survival rate (83%, 10 out of 12 animals) compared with 50% (6 of 12) in control animals and 27% (3 of 11) in animals treated during endotoxinemia. Pre-treatment with candesartan resulted in higher cardiac output, mixed venous oxygen saturation, arterial standard base-excess, portal venous blood flow during endotoxin infusion compared with controls and animals treated during endotoxinemia. No adverse effects were found on neither systemic nor renal circulation.

CONCLUSION

The favorable results of AT1 receptor blockade prior to endotoxinemia are lost when blockade is established during endotoxinemia demonstrating the importance of the renin-angiotensin system and its dynamic involvement in acute endotoxinemic shock.

Garlic supplementation increases testicular testosterone and decreases plasma corticosterone in rats fed a high protein diet

The effects of garlic supplementation on protein metabolism were investigated by measuring testis testosterone and plasma corticosterone in rats fed diets with different protein levels. In Experiment 1, rats were fed experimental diets with different protein levels (40, 25 or 10 g/100 g casein) with or without 0.8 g/100 g garlic powder. After 28 d of feeding, testosterone contents in the testis were significantly higher and plasma corticosterone concentrations were significantly lower in rats fed 40 and 25% casein diets with garlic powder than in those fed the same diets without garlic powder. Urinary excretion of 17-ketosteroid (an index of testosterone), nitrogen balance and hepatic arginase activity were significantly higher in rats fed the 40% casein diet with garlic powder than in the 40% casein controls. In Experiment 2, the effect of diallyldisulfide (a major volatile sulfur-containing compound in garlic) on the secretion of luteinizing hormone (LH) from the pituitary gland, which regulates testosterone production in the testis, was investigated in anesthetized rats. Plasma LH concentration increased dose dependently after administration of diallyldisulfide (P < 0.01, r = 0.558). These results suggest that dietary supplementation with 0.8 g/100 g garlic alters hormones associated with protein anabolism by increasing testicular testosterone and decreasing plasma corticosterone in rats fed a high protein diet.

Endothelin-1 blockade corrects mesenteric hypoperfusion in a porcine low cardiac output model

OBJECTIVE

To study the importance of endothelin-1-induced vasoconstriction in a model of acute and maintained low cardiac output, by investigating regional changes within the mesenteric and particularly the intestinal mucosal circulation.

DESIGN

Prospective, controlled animal study.

SETTING

University-affiliated research laboratory.

SUBJECTS

Thirteen fasted, anesthetized, mechanically ventilated landrace pigs.

MEASUREMENTS AND MAIN RESULTS

Cardiac output, portal venous blood flow, renal arterial flow, jejunal mucosal microcirculation by laser Doppler flowmetry, jejunal capnotonometry (Pco2 gap), and jejunal mucosal oxygenation (tPo2) were monitored. Cardiac tamponade was established to reduce portal venous blood flow to a preset end point at two thirds of baseline. Measurements were made at baseline, after 90 mins of cardiac tamponade, and 90 mins after the administration of the combined endothelinA/endothelinB antagonist tezosentan at 1 mg.kg-1.hr-1 during tamponade in seven animals. Six animals served as time controls and received only the vehicle. Cardiac tamponade decreased portal venous blood flow, renal arterial flow, and laser Doppler flowmetry, whereas the Pco2 gap increased. The change in tPo2 failed to gain statistical significance (p =.08). Administration of tezosentan during tamponade restored portal venous blood flow and laser Doppler flowmetry to baseline values, increased tPo2 above baseline, and decreased Pco2 gap. No effect on renal arterial flow was observed. Investigated variables remained unchanged in control animals after induction of cardiac tamponade.

CONCLUSIONS

Endothelin-1 blockade in acute cardiac failure improves mesenteric, but not renal, perfusion, illustrating the regional importance of endothelin-1-induced vasoconstriction. Importantly, endothelin-1 blockade restored mucosal blood flow and oxygenation, which might be particularly interesting considering the implications for maintenance of mucosal barrier integrity in low output states.

Descending aortic blood flow and cardiac output: a clinical and experimental study of continuous oesophageal echo-Doppler flowmetry

BACKGROUND

Several studies have demonstrated that perioperative optimisation of oxygen delivery and haemodynamics can reduce mortality and morbidity for high-risk surgical patients. To optimise cardiac output, reliable, continuous and "less invasive" methods for measuring cardiac output are urgently needed.

METHODS

Eight landrace pigs were studied during experimental repeated cardiac tamponade and 14 patients during liver transplantation. Aortic blood flow was measured by using transoesophageal echo-Doppler technique. A total of 91 paired measurements of aortic blood flow and cardiac output with different techniques were performed in the pigs and 124 paired measurements in the patients.

RESULTS

Transoesophageal echo-Doppler did provide continuous real-time monitoring of the rapid and dramatic haemodynamic changes occurring during cardiac tamponade and during liver transplantation, while only intermittent information was obtained from the bolus thermodilution technique. Changes in haemodynamics were more difficult to detect with the "continual" cardiac output thermodilution technique. Changes in aortic blood flow closely followed changes in cardiac output determined by the bolus thermodilution technique both in pigs (r= 0.89) and in patients (r=0.80). In patients, aortic blood flow constituted about 70% of cardiac output determined by the bolus thermodilution technique.

CONCLUSIONS

A combined echo-Doppler technique can be valuable for continuous monitoring of haemodynamic changes in the perioperative setting, and changes in aortic blood flow agree well with corresponding changes in cardiac output intermittently obtained by thermodilution cardiac output measurements. With the combined echo-Doppler technique a proper position of the Doppler beam is greatly facilitated by the M-mode echo visualisation of the aortic wall and aortic cross-sectional area is continuously measured.

Hypertonic saline-dextran improves intestinal perfusion and survival in porcine endotoxin shock

OBJECTIVE

To examine the effects of hypertonic (7.5%) saline-6% dextran 70 (HSD) and isotonic (0.9%) saline-6% dextran 70 (ISD) on cardiovascular function and intestinal perfusion in experimental endotoxin shock.

DESIGN

Experimental, randomized, unblinded, interventional study.

SETTING

University experimental animal laboratory.

SUBJECTS

Anesthetized and mechanically ventilated landrace pigs (n = 24).

INTERVENTIONS

Induction of endotoxin (ET) shock by infusion of Escherichia coil lipopolysaccharide endotoxin (serotype 0111: B4) followed by no fluid treatment (control; C) or small-volume (4 mL/kg) treatment with HSD or ISD.

MEASUREMENTS AND MAIN RESULTS

Mean arterial pressure, central venous pressure, pulmonary artery pressure, pulmonary artery occlusion pressure, cardiac output, portal vein blood flow, intestinal microcirculation, intramucosal (regional) P(CO2), intestinal-arterial gap of CO2, and intramucosal pH were monitored, and blood gases were analyzed. Infusion of ET resulted in hypokinetic shock, which in untreated animals led to cardiovascular deterioration and a survival rate of only 33% at 300 mins after start of ET infusion. ISD treatment transiently improved hemodynamic variables and mucosal blood flow but did not affect the survival rate vs. C. Significant beneficial, long-lasting effects of HSD infusion on hemodynamics, especially on mucosal blood flow and intramucosal pH, were demonstrable, resulting in a survival rate of 86%. The relative risk of death at 300 mins was 1.20 for ISD vs. C and 0.17 for HSD vs. C.

CONCLUSION

Small-volume HSD resuscitation is much more effective than ISD resuscitation. Variables that were improved include cardiac output, portal blood flow, and intestinal mucosal blood flow in ET shock, all of which improve survival. Such beneficial effects of HSD on splanchnic perfusion may be of value in treating critically ill septic patients in the intensive care unit.

Allylthiamindisulfide and related compounds enhance thermogenesis with increasing noradrenaline and adrenaline secretion in rats

The effects of allylthiamindisulfide, an allyl derivative of thiamin, and related compounds on thermogenesis were investigated by measuring noradrenaline and adrenaline secretion and the temperatures of interscapular brown adipose tissue (IBAT) and rectum in rats. In Experiment 1, the effects of the administrations of allylthiamindisulfide and related compounds on noradrenaline and adrenaline secretion were evaluated as compared to thiamin in anesthetized rats. The administration of allylthiamindisulfide significantly increased the plasma concentrations of noradrenaline and adrenaline. These increases were dose dependent, while that of thiamin was not. Four synthetic compounds related to allylthiamindisulfide also increased the plasma adrenaline and noradrenaline concentrations. In Experiment 2, the effects of allylthiamindisulfide on thermogenesis were investigated by the direct measurement of temperatures in the IBAT and rectum in anesthetized rats, and compared to the effects induced by thiamin and diallyldisulfide. The temperatures in the IBAT and rectum were significantly increased by the administration of allylthiamindisulfide and diallyldisulfide, while there was no significant increase as the result of thiamin administration. These results suggest that allylthiamindisulfide and related compounds enhance thermogenesis by increasing noradrenaline and adrenaline secretion in rats.

Allyl-containing sulfides in garlic increase uncoupling protein content in brown adipose tissue, and noradrenaline and adrenaline secretion in rats

The effects of garlic supplementation on triglyceride metabolism were investigated by measurements of the degree of thermogenesis in interscapular brown adipose tissue (IBAT), and noradrenaline and adrenaline secretion in rats fed two types of dietary fat. In Experiment 1, rats were given isoenergetic high-fat diets containing either shortening or lard with or without garlic powder supplementation (8 g/kg of diet). After 28 d feeding, body weight, plasma triglyceride levels and the weights of perirenal adipose tissue and epididymal fat pad were significantly lower in rats fed diets supplemented with garlic powder than in those fed diets without garlic powder. The content of mitochondrial protein and uncoupling protein (UCP) in IBAT, and urinary noradrenaline and adrenaline excretion were significantly greater in rats fed a lard diet with garlic powder than in those fed the same diet without garlic. Other than adrenaline secretion, differences due to garlic were significant in rats fed shortening, also. In Experiment 2, the effects of various allyl-containing sulfides present in garlic on noradrenaline and adrenaline secretion were evaluated. Administration of diallyldisulfide, diallyltrisulfide and alliin, organosulfur compounds present in garlic, significantly increased plasma noradrenaline and adrenaline concentrations, whereas the administration of disulfides without allyl residues, diallylmonosulfide and S-allyl-L-cysteine did not increase adrenaline secretion. These results suggest that in rats, allyl-containing sulfides in garlic enhance thermogenesis by increasing UCP content in IBAT, and noradrenaline and adrenaline secretion.

[Helical CT guided lumar sympathetic ganglion block]

Helical CT scan was used as a guide for lumbar sympathetic ganglion block. By examining anatomical location of the block site with the sequential fluoroscope pictures of helical CT scan, we succeeded in the block of sympathetic ganglion easily. It is possible by the use of sequential CT picture to reduce the risk of puncturing essential organ such as the kidney, descending aorta, inferior vena cava and so on. Moreover, we can expect that application of helical CT scan will raise the success rate of block and will decrease the time necessary for the performance of block.

Effects of low protein intake on protein metabolism of Papua New Guinea highlanders studied with [15N]glycine

The effects of low protein intake on protein metabolism, including the size of pools and the protein synthesis rates, were studied by use of [15N]glycine in Papua New Guinea highlanders. Studies were made on 9 men between October and December in 1982. In experiment 1, two subjects were given a protein-free diet (PFD) containing 49.1 kcal/kg of energy. In experiment 2, subjects were given a sweet-potato diet (SPD) containing 45.4 kcal/kg of energy and 0.507 g/kg of protein for 8 days, and then were given a low-protein sweet-potato diet (LPSPD) containing 50.0 kcal/kg of energy and 0.265 g/kg of protein. During the SPD period, the sizes of the metabolic and active protein pools (mean +/- SD) were 270 +/- 134 mgN/kg and 362 +/- 107 mgN/kg, respectively, and the rates of active and inactive protein synthesis were 463 +/- 161 mgN/kg/day and 299 +/- 38 mgN/kg/day, respectively. During the LPSPD period, the sizes of the metabolic pool and active protein pool were 131 +/- 64 mgN/kg and 378 +/- 106 mgN/kg, respectively, and the rates of active and inactive protein synthesis were 490 +/- 206 mgN/kg/day and 280 +/- 26 mgN/kg/day, respectively. The protein metabolism in the LPSPD showed no significant difference from the SPD. The results suggest that, when the energy levels were approximately the same, protein metabolism in Papua New Guinea highlanders was maintained in spite of the decrease in protein intake.

Changes in serum glucose and serum growth hormone levels during pituitary surgery

During transsphenoidal surgery, serum growth hormone (GH) and serum glucose levels were measured in five acromegalic patients with diabetes or glucose intolerance, three acromegalic patients without diabetes or glucose intolerance, and six patients with prolactinoma. Preoperative steroid administration produced a significant increase in serum glucose level in acromegalic patients with diabetes or glucose intolerance, whereas in the other two groups no significant change in serum glucose level was found. After surgery started, there was a statistically significant increase in serum glucose level above baseline levels in all three groups. Serum GH levels decreased after commencement of surgery in acromegalic patients, and tumor manipulation did not produce a statistically significant increase in serum GH levels. Simultaneous increases in serum glucose and serum GH levels upon tumor manipulation did not occur in any group. We conclude that preoperative steroid administration in patients with high serum levels of GH in association with diabetes or glucose intolerance increases serum glucose levels, and that, after commencement of surgery, GH has only a minor role in the changes of serum glucose levels.

Effects of restricted diet on protein metabolism measured by [15N]glycine in high-fat-diet-induced obese rats

The effect of restricted diets on protein metabolism was studied in obese rats (obesity had been induced by ad libitum feeding of a diet containing 30% fat and 25% casein). The obese rats were fed on one of three restricted diets, each containing 5% fat, for 2 weeks (restricted feeding groups); a high-protein diet (HPD, 50% casein), a standard-protein diet (SPD, 25% casein), or a low-protein diet (LPD, 5% casein). The food intake was restricted to 5 g per day per rat. On the eleventh day, the rats were given [15N]glycine orally, and 4 days later, they were killed. The restricted feeding groups all showed similar weight losses (about 100 g), 2 weeks after the start of the restricted diet. The 15N distribution in whole body was measured and results were compared with those of control rats given 5%- or 30%-fat diet ad libitum. The whole-body distribution of 15N in the HPD group was similar to that in the rats fed ad libitum although the diet intake was restricted. The results suggested that the amount of protein in a restricted diet is important for maintenance of protein metabolism in obese rats.

Effects of low energy diets on protein metabolism studies with [15N]glycine in obese patients

The effects of low energy diets on protein metabolism in terms of the metabolic pool, active protein pool, and active and inactive protein synthesis rates were studied using [15N]glycine in five obese patients (percentage of ideal body weight, 120-190%). For 10 days, the patients were given a control diet containing 2,000 kcal of energy and 80 g of protein. For the next 2 weeks, they were given Diet A with 1,100 kcal of energy and 70 g of protein, and for the last 2 weeks given Diet B with 1,100 kcal of energy and 50 g of protein. During the Diet A period, the active protein pool and the active and inactive protein synthesis rates were about the same as during the control diet period, although the metabolic pool tended to be slightly smaller than during the control diet period. During the Diet B period, the metabolic pool, active protein pool, and active protein synthesis rate were all significantly different from the values during the control diet period. The results suggest that protein metabolism in obese patients is not maintained with less than 70 g of protein daily when energy intake was restricted to 1,100 kcal/day.

Relationship between protein intake and nitrogen balance in obese patients on low energy diet

The effect of nitrogen intake on nitrogen balance was studied in six obese patients receiving low energy diets. They were given a control diet containing 2,000 kcal of energy and 80 g of protein for the first ten days. Then they were given Diet A with 1,100 kcal of energy and 70 g of protein for the next 2 weeks, followed by Diet B with 1,100 kcal of energy and 50 g of protein for 2 weeks. The relationship between nitrogen intake (X, mg/kg) and nitrogen balance (Y, mg/kg) during the low energy diet periods was statistically significant, with Y = 0.388X-60.32 (SD = 17.71, r = +0.67, n = 11, p less than 0.05). The nitrogen and protein requirements were estimated from this equation to be 201.1 mg/kg and 1.26 g/kg, respectively. In our experiment, the nitrogen balance in obese patients was well maintained although total energy was reduced to 1,100 kcal/day in Diet A. It is suggested that protein quantity in the diets should be taken into account when a low energy diet is used for the treatment of obesity.

Effects of rice fiber on fecal weight, apparent digestibility of energy, nitrogen and fat, and degradation of neutral detergent fiber in young men

The effects of rice fiber on fecal weight, transit time, frequency of defecations, digestibility of nutrients and blood status were investigated in 5 healthy young men. Each of them consumed a brown rice diet and then a polished rice diet for 2 weeks respectively. Both diets contained 1.2 g protein per kg body weight. The brown rice diet contained 2 times as much dietary fiber as the polished rice diet. When they consumed the brown rice diet, it showed an increase of fecal weight and decrease of digestibility of energy, nitrogen and fat. Nitrogen balance was not significantly different and kept zero balance on both diets. Concentration of plasma cholesterol was not significantly different. The results suggest that rice fiber produced an increase in fecal weight, which is assumed to be effective in preventing colonic disease in advanced countries and does not affect plasma lipid level.

Endogenous nitrogen excretion in male highlanders of Papua New Guinea

Endogenous nitrogen excretion was examined in highlanders of Papua New Guinea. Eight highlanders were fed a semisynthetic protein-free diet with about 49 kcal/kg of energy for 11 days. At the end of this period they excreted 29.2 +/- 4.0 mg N/kg of urinary nitrogen and 13.9 +/- 2.5 mg N/kg of fecal nitrogen per day. When the values were expressed per basal metabolic rate (BMR), they were 1.25 +/- 0.19 mg N/kcal BMR for urine and 0.59 +/- 0.08 mg N/kcal BMR for feces. The total amount was calculated as 43.1 +/- 4.3 mg N/kg (1.84 +/- 0.18 mg N/kcal BMR). Endogenous urinary nitrogen excretion in highlanders was the lowest so far reported; the effects of ethnic and nutritional backgrounds on obligatory urinary N loss were examined but no clear explanation was found for the highlanders' low value.

[Electron microscopic study of choroid plexus in experimentally induced hydrocephalic dog (author's transl)]

Choroid plexus in experimentally induced hydrocephalic dogs according to the Wisniewski's method was examined by an electron microscope. Epithelial cell of the choroid plexus appeared in various deformation and formed a marked dilatation of extracellular spaces between apposed two cell membranes and at the basal interdigitation. Dilatation of the extracellular space was more pronounced at the stromal side of the epithelial layer. This finding might be due to anatomical specificities of apposed epithelial cell membranes and not only indicate a disturbance of the CSF secretion. According to the dilatation of extracellular space, apposed two epithelial cell membranes separated each other, however, at sites of intercellular junctions, adjacent cell membranes remained closely apposed. The dilated extracellular space at the basal site continued to the dilated intercellular space, while, no continuity was recognized between the dilated intercellular space and ventricular lumen. These extracellular speces appeared low electron density and showed little specific structure. No particular change was recognized in organelles in the epithelial cell, except increased pinocytotic vesicles in number. Stroma of the choroid plexus appeared edematous, that was, electron density was low and a few cellular and stromal elements were found. Capillary vessels showed almost normal structure. In hydrocephalic dogs also in normal one, Lanthanum infused into lateral ventricle precipitated on the surface of microvilli of choroid plexus epithelial cell. The Lanthanum, entered through ventricular end of intercellular space, was blocked to penetrate beyond the intercellular junction (zonula occludens) and any bit of the tracer was not found in the dilated extracellular space. The tracer was found neither in epithelial cell nor in stroma. These findings of tracer-study may indicate that the CSF absorption through the choroid plexus is not increased in chronic hydrocephalus. Consequently, the ultrastructural changes of the choroid plexus in chronic hydrocephalus, that is, enlarged extracellualr space, increased pinocytotic vesicles and edematous stroma, are thought to suggest a disturbance of CSF secretion from the choroid plexus.