Black ant stings caused by Pachycondyla sennaarensis: a significant health hazard.
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Several species of ants cause stings, but not all lead to allergic reactions. We present a series of cases of allergic reactions following insect bites or stings that presented to our emergency department and that were caused by the black samsum ant (Pachycondyla sennaarensis). Reactions ranged from mild allergic reactions to severe anaphylactic shock. Patients were treated with subcutaneous epinephrine 0.3 mg, intravenous methylprednisolone 125 mg, intravenous diphenhydramine HCl 50 mg, and intravenous normal saline as appropriate. These cases illustrate the range of clinical presentations to black ant stings, which can include severe reactions, indicating that ant stings are a significant public health hazard in Saudi Arabia. Physicians in the Middle East and Asia need to be aware of ant stings as a cause of severe allergic reactions. (+info)
Safety of a peanut oral immunotherapy protocol in children with peanut allergy.
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Effects of anserine on the renal sympathetic nerve activity and blood pressure in urethane-anesthetized rats.
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Previous studies have demonstrated that central injection of L-carnosine (beta-alynyl-L-histidine), dipeptide synthesized in mammalian muscles, affects renal sympathetic nerve activity (RSNA) and blood pressure (BP) in anesthetized rats. In the present study, using urethane-anesthetized rats, we examined the dose-dependent effects of intravenous (IV) injection of various doses of anserine, dipeptide of similar structure to L-carnosine, on RSNA, BP and heart rate (HR). We found that injection of a low dose of anserine (1 microg) significantly suppressed RSNA, BP and HR. Conversely, a high dose (1000 microg) of anserine significantly elevated RSNA, BP and HR. Pretreatment with lateral cerebral ventricular (LCV) injection of thioperamide, a histaminergic H(3)-receptor antagonist, eliminated the effects of a low dose of anserine on RSNA, BP and HR. LCV injection of diphenhydramine, a histaminergic H(1)-receptor antagonist, abolished the effects of a high dose of anserine on RSNA, BP and HR. These findings suggest that anserine affects RSNA, BP and HR in a dose-dependent manner, and that the histaminergic nerve may be involved in the dose-different effects of anserine in rats. (+info)
Hypnotic and sleep quality-enhancing properties of kavain in sleep-disturbed rats.
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The present study was performed to investigate the effects of kavain on the sleep-wake cycle in comparison with that of rilmazafone and diphenhydramine using sleep-disturbed rats. Electrodes for the electroencephalogram (EEG) and electromyogram (EMG) were implanted into Wistar rats. Total awake time, non-rapid eye movement (non-REM) sleep and rapid eye movement (REM) sleep were measured for 6 h. Kavain and rilmazafone showed a significant shortening in sleep latency, decreased awake time, and increased non-REM sleep time. On the other hand, significant shortening of the sleep latency was observed following the administration of diphenhydramine, while no effects were observed on the awake and non-REM sleep time. Moreover, kavain showed a significant increase in delta activity during non-REM sleep in sleep-disturbed rats, whereas a significant decrease in delta power during non-REM sleep was observed with rilmazafone. These results clearly indicate that kavain is a compound with not only hypnotic effects, but also sleep quality-enhancement effects. (+info)
Role of mast cells in ion transport abnormalities associated with intestinal anaphylaxis. Correction of the diminished secretory response in genetically mast cell-deficient W/Wv mice by bone marrow transplantation.
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To investigate the role of mast cells in transport abnormalities during intestinal anaphylaxis, we examined responses to antigen in isolated intestinal preparations from ovalbumin-sensitized genetically mast cell-deficient WBB6F1-W/Wv (W/Wv) mice and congenic normal WBBGF1(-)+/+ (+/+) mice. Changes in ion transport (primarily secretion of chloride ions) were indicated by increases in short-circuit current (Isc). In tissues from +/+ mice, antigen caused increases in Isc which were significantly inhibited by antagonists to histamine (diphenhydramine) and serotonin (ketanserin), by a cyclooxygenase inhibitor (piroxicam) and by a neurotoxin (tetrodotoxin). In preparations from W/Wv mice, antigen-stimulated responses were approximately 30% of that in +/+ mice and were inhibited only by piroxicam. Responses to electrical transmural stimulation of nerves were approximately 50% in W/Wv versus +/+ mice, and were inhibited by antagonists of mast cell mediators in +/+ but not W/Wv mice. Reconstitution of mast cells in W/Wv mice by intravenous injection of +/+ bone marrow cells restored the normal responses to both antigen and nerve stimulation. Our results indicate that mast cell-dependent mechanisms are primarily responsible for the ion secretion associated with intestinal anaphylaxis, but that other cells are also involved. In addition, our data provide evidence for the functional importance of bidirectional communication between nerves and mast cells in the regulation of ion transport in the gastrointestinal tract. (+info)
Imaging histamine H1 receptors in the living human brain with carbon-11-pyrilamine.
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The brain distribution and kinetics of the H1 receptor antagonist, carbon-11-pyrilamine (11C-pyrilamine) were examined in vivo in two baboons and one human by positron emission tomography. After i.v. administration of the tracer, brain activity peaked within 20 min after injection and subsequently decreased, reflecting reversible binding to the receptor. Pretreatment with 1 mg/kg diphenhydramine reduced the brain activity at 70 min by 33%, 29%, 26%, and 23% of the control values in frontal cortex, temporal cortex, hippocampus, and cerebellum, respectively. Coinjection of 1 and 5 mg/kg cold pyrilamine reduced the activity at 70 min by 40%, 36%, 34%, and 30% in frontal, temporal, hippocampus and cerebellum, respectively. The in vivo specific binding to the H1 receptors in different brain regions at 70 min after injection correlated with the in vitro H1 histamine receptors distribution in human brain tissue obtained at autopsy, with high values in the frontal and temporal cortex and low values in cerebellum and brain stem. In the healthy human volunteer study, the value of washout of radioactivity increased by about 50% after injection of 0.7 mg/kg diphenhydramine. (+info)
Accelerated Ca2+ entry by membrane hyperpolarization due to Ca2+-activated K+ channel activation in response to histamine in chondrocytes.
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