Release of galactosyltransferase from human platelets and a subset of monocytes in culture

We show that human monocytes and platelets release considerable amounts of galactosyltransferase (GT) in serum-free culture as measured by the amount of incorporation of 3H-galactose into ovalbumin. Enzyme production was the greatest among medium-sized mononuclear cells separated by counter-current elutriation. The cells were adherent and positive for the monocyte-specific monoclonal antibody FMC-32. The activity in the monocyte fractions was not due to platelet contamination as shown from experiments in which platelets or platelet antigens were eliminated. Cell viability decreased by less than 3% during the overnight culture, and results from cell disruption experiments showed that the enzyme was not released from dead or dying cells. Cycloheximide inhibited release during 20 hours culture. Approximately 50% of the enzyme in the cell culture supernatant was pelletable at 105,000 g. Platelets released the enzyme more rapidly than did monocytes and were readily stimulated by thrombin to release more GT. Thrombin also increased monocyte GT activity after overnight incubation, but other stimulants, zymosan and lipopolysaccharide (LPS), decreased release. We conclude that GT is released into culture supernatants by platelets and by a subset of peripheral blood monocytes. These sources may account for a significant proportion of the serum enzyme and may be important in modification of extracellular carbohydrates during inflammation and coagulation.     

A Rare Case of Acute Right-Sided Colonic Diverticulitis Presenting as Pancreatitis

Background

This case report highlights the clinical presentation, radiologic findings, and medical management of a case of right colonic diverticulitis (RCD) with concomitant pancreatitis, a rare and easily missed entity in the emergency department (ED) of Western hemisphere countries. In our report, we present and discuss a case of RCD that led to pancreatitis in a female Asian patient. We review the epidemiology, diagnosis, and management of this disorder, and also discuss some complications associated with RCD. The importance of considering this pathologic entity within the ED differential even in those patients presumed to be at low risk for this condition is also explained, as this can prevent inappropriate surgical intervention for this presentation.

Bedside ultrasound for the detection of diabetic myonecrosis

Diabetic myonecrosis is an uncommon complication of diabetes mellitus. There are fewer than 50 cases reported in the general medical literature. Patients classically complain of the abrupt onset of diffuse anterior thigh pain with no signs of overlying infection or signs of systemic toxicity.Because of the difficulty in diagnosis, most patients endure multiple medical visits until appropriate imaging modalities are obtained. Currently, magnetic resonance imaging (MRI) or tissue biopsy is considered the gold standard for diagnosis. This is the first case reported in the literature of diabetic myonecrosis detected in the ED by bedside ultrasound. We hope that with the continued use of bedside ultrasound, more physicians will be able to determine abnormal tissue architecture allowing for the early detection of diabetic myonecrosis.     

Distal Revascularisation with Interval Ligation (DRIL): An Experience

INTRODUCTION

The global increase of chronic renal failure has resulted in a growing number of patients on haemodialysis using arteriovenous fistulas (AVFs). By virtue of their very function, AVFs at times shunt blood away from regions distally, resulting in an ischaemic steal syndrome. Distal revascularisation with interval ligation (DRIL) has been described as a procedure to treat symptomatic ischaemic steal. We present our experience in the management of this complication.

PATIENTS AND METHODS

Six patients with severe ischaemic steal were treated using a DRIL procedure between May 2004 and June 2007. There were three males and three females, all with elbow brachiocephalic AVFs. Symptoms ranged from severe rest pain to digital gangrene. Published results from international studies of 135 DRIL procedures were also reviewed.

RESULTS

Vascular access was maintained along with the elimination of ischaemic symptoms in the six patients using an ipsilateral reversed basilic vein graft. Interval ligation of the distal brachial artery was performed at the same time. All patients showed immediate and sustained clinical improvement of symptoms with a demonstrable increase in digital pulse oximetry.

CONCLUSIONS

DRIL is a beneficial treatment option that has proven successful at alleviating ischemic steal symptoms and preserving vascular access. This avoids placement of central lines, its associated risks, and the need to create an alternative sited fistula.     

NS11021, a novel opener of large-conductance Ca2+-activated K+ channels,enhances erectile responses in rats

Background and purpose:

Large-conductance Ca²⁺-activated K⁺ channels (BK_Ca), located on the arterial and corporal smooth muscle, are potential targets for treatment of erectile dysfunction (ED). This study investigated whether NS11021 (1-(3,5-Bis-trifluoromethyl-phenyl)-3-[4-bromo-2-(1H-tetrazol-5-yl)-phenyl]-thiourea), a novel opener of BK_Ca channels, relaxes erectile tissue in vitro and enhances erectile responses in intact rats. The effects were compared with sildenafil, an inhibitor of phosphodiesterase type 5.

Experimental approach:

Patch clamp was used to record whole cell current in rat isolated corpus cavernosum smooth muscle cells (SMCs) and human umbilical vein endothelial cells (HUVECs). Isometric tension was measured in intracavernous arterial rings and corpus cavernosum strips isolated from rats and men, and simultaneous measurements of intracellular Ca²⁺ concentration ([Ca²⁺]_i) and tension were performed in intracavernous arteries. Erectile response was measured in anaesthetized rats.

Key results:

In patch clamp recordings, NS11021 increased currents sensitive to the selective BK_Ca channel blocker, iberiotoxin (IbTX) in SMCs, but did not modulate K⁺ current in HUVECs. NS11021 reduced [Ca²⁺]_i and tension in penile arteries. IbTX inhibited the vasorelaxation induced by NS11021 and sildenafil in human erectile tissue. NS11021 and sildenafil but not vehicle increased erectile responses in anaesthetized rats, an effect which was abolished after pretreatment with tetraethylammonium.

Conclusions and implications:

NS11021 leads to relaxation of both intracavernous arteries and corpus cavernosum strips primarily through opening of BK_Ca channels. It is also effective in facilitating erectile responses in anaesthetized rats. These results suggest a potential for use of BK_Ca openers in the treatment of ED.     

Prostanoid receptor antagonists: development strategies and therapeutic applications

Background and purpose:

Histamine H₃ receptor antagonists are currently being evaluated in clinical trials for a number of central nervous system disorders including narcolepsy. These agents can increase wakefulness (W) in cats and rodents following acute administration, but their effects after repeat dosing have not been reported previously.

Experimental approach:

EEG and EMG recordings were used to investigate the effects of acute and repeat administration of the novel H₃ antagonist GSK189254 on the sleep–wake cycle in wild-type (Ox+/+) and orexin knockout (Ox−/−) mice, the latter being genetically susceptible to narcoleptic episodes. In addition, we investigated H₃ and H₁ receptor expression in this model using radioligand binding and autoradiography.

Key results:

In Ox+/+ and Ox−/− mice, acute administration of GSK189254 (3 and 10 mg·kg⁻¹ p.o.) increased W and decreased slow wave and paradoxical sleep to a similar degree to modafinil (64 mg·kg⁻¹), while it reduced narcoleptic episodes in Ox−/− mice. After twice daily dosing for 8 days, the effect of GSK189254 (10 mg·kg⁻¹) on W in both Ox+/+ and Ox−/− mice was significantly reduced, while the effect on narcoleptic episodes in Ox−/− mice was significantly increased. Binding studies revealed no significant differences in H₃ or H₁ receptor expression between Ox+/+ and Ox−/− mice.

Conclusions and implications:

These studies provide further evidence to support the potential use of H₃ antagonists in the treatment of narcolepsy and excessive daytime sleepiness. Moreover, the differential effects observed on W and narcoleptic episodes following repeat dosing could have important implications in clinical studies.     

Rapid brain penetration of interleukin-1 receptor antagonist in rat cerebral ischaemia: pharmacokinetics,distribution, protection

Background and purpose:

Limited data on the brain penetration of potential stroke treatments have been cited as a major weakness contributing to numerous failed clinical trials. Thus, we tested whether interleukin-1 receptor antagonist (IL-1RA), established as a potent inhibitor of brain injury in animals and currently in clinical development, reaches the brain via a clinically relevant administration route, in experimental stroke.

Experimental approach:

Male, Sprague-Dawley rats [either naïve or exposed to middle cerebral artery occlusion (MCAo)] were given a single s.c. dose of IL-1RA (100 mg·kg⁻¹). The pharmacokinetic profile of IL-1RA was assessed in plasma and CSF up to 24 h post-administration. Brain tissue distribution of administered IL-1RA was assessed using immunohistochemistry. In a separate experiment, the neuroprotective effect of the single s.c. dose of IL-1RA in MCAo was assessed versus a placebo control group.

Key results:

A single s.c. dose of IL-1RA reduced damage caused by MCAo by 33%. This dose resulted in sustained, high concentrations in plasma and CSF, penetrated brain tissue exclusively in areas of blood–brain barrier breakdown and co-localized with morphologically viable neurones. CSF concentrations did not reflect massive parenchymal infiltration of IL-1RA in MCAo animals compared to naïve.

Conclusions and implications:

These data are the first to show that a potential treatment for stroke, IL-1RA, rapidly reaches salvageable brain tissue via an administration route that is clinically relevant. This allows confidence that IL-1RA, as a candidate for further clinical development, is able to confer its protective actions both peripherally and centrally.     

自身免疫性肝炎的现代处理观点

自身免疫性肝炎（AIH）常见于女性,表现为肝酶异常（转氨酶升高）、血清自身抗体如抗核抗体（ANA）、抗平滑肌抗体（SMA）、抗可溶性肝抗原抗体／肝胰抗原（SLA／LP）、抗肝肾做粒体抗体（LKM）1阳性和γ-免疫球蛋白升高,但并非所有AIH患者均出现上述特征。AIH的组织学特点为界面性肝炎,以浆细胞和淋巴细胞浸润为主,但无特征性组织学表现。AIH的确诊较为困难,目前的流行病学资料中报道的AIH实际发病率和患病率可能偏低。     

Alveolar recruitment strategy and PEEP improve oxygenation,dynamic compliance of respiratory system and end‐expiratory lung volume in pediatric patients undergoing cardiac surgery for congenital heart disease

Objective: Optimizing alveolar recruitment by alveolar recruitment strategy (ARS) and maintaining lung volume with adequate positive end‐expiratory pressure (PEEP) allow preventing ventilator‐induced lung injury (VILI). Knowing that PEEP has its most beneficial effects when dynamic compliance of respiratory system (Crs) is maximized, we hypothesize that the use of 8 cm H₂O PEEP with ARS results in an increase in Crs and end‐expiratory lung volume (EELV) compared to 8 cm H₂O PEEP without ARS and to zero PEEP in pediatric patients undergoing cardiac surgery for congenital heart disease. Methods: Twenty consecutive children were studied. Three different ventilation strategies were applied to each patient in the following order: 0 cm H₂O PEEP, 8 cm H₂O PEEP without an ARS, and 8 cm H₂O PEEP with a standardized ARS. At the end of each ventilation strategy, Crs, EELV, and arterial blood gases were measured. Results: EELV, Crs, and P_aO₂/FiO₂ ratio changed significantly (P < 0.001) with the application of 8 cm H2O + ARS. Mean P_aCO₂– PETCO₂ difference between 0 PEEP and 8 cm H2O PEEP + ARS was also significant (P < 0.05). Conclusion: An alveolar recruitment strategy with relative high PEEP significantly improves Crs, oxygenation, P_aCO₂– PETCO₂ difference, and EELV in pediatric patients undergoing cardiac surgery for congenital heart disease.