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Biomedical subjects

J R Mozingo

Publications and source records attributed to J R Mozingo.

10 recordsLinked to original sources
PubMed1997

Potentiation of pyridostigmine bromide toxicity in mice by selected adrenergic agents and caffeine.

Pyridostigmine bromide (PB) is a reversible cholinesterase inhibitor used routinely in the treatment of myasthenia gravis and recently by the US Army as a prophylactic agent against potential nerve gas attack in the Persian Gulf War. Pyridostigmine has been implicated as one of several possible causative factors associated with Persian Gulf illnesses. To investigate toxic interactions between PB and other drugs, male ICR mice received contralateral ip injections of either a selected adrenergic drug or caffeine, followed 15 min later by PB. Representative isobolograms plotted for each drug interaction illustrate that a beta-adrenoceptor agonist (isoproterenol), selective beta 2-adrenoceptor agonists (salbutamol, terbutaline), alpha 1- and alpha 2-adrenoceptor antagonists (yohimbine, phentolamine, prazosin), as well as the stimulant caffeine, strongly potentiate the lethal effect of PB. Agents with agonist activity at both alpha- and beta-adrenoceptors (epinephrine, norepinephrine) additively increase PB-induced lethality. The potentiation of toxicity between PB and these agents was counteracted by pretreatment with atropine and atropine methyl nitrate. An alpha 2-adrenoceptor agonist (clonidine) and beta-adrenoceptor antagonists (propranolol, nadolol, acebutolol) did not increase PB-induced lethalities. These data demonstrate a toxic synergism between PB, several commonly used classes of adrenergic agents and caffeine when exposure occurs in different combinations. Future studies into the mechanism(s) of these interactions may bring into question the usage of PB as a protective agent in combat conditions as well as delineate any possible contributions of the drug to Persian Gulf illnesses.

Adrenergic Agents↗
PubMed1995

Antidotal efficacy of alpha-ketoglutaric acid and sodium thiosulfate in cyanide poisoning.

Alpha-ketoglutaric acid and sodium thiosulfate antagonize the toxic effects of cyanide. The present study was performed to test whether a synergistic effect may occur. The alpha-ketoglutaric acid/sodium thiosulfate solutions were injected intraperitoneally into mice prior to exposure to hydrogen cyanide (HCN) in a dynamic inhalation chamber or preceding an intraperitoneal injection of sodium cyanide (NaCN). All lethal concentration (LCT) and lethal dose (LD) values were determined after a period of 24 h. Alpha-ketoglutaric acid alone provided no protection at 250 mg/kg when challenged with HCN. Sodium thiosulfate 500 mg/kg provided a 5% protection. However, when these doses of alpha-ketoglutaric acid and sodium thiosulfate were combined, protection was increased by 18%. Alpha-ketoglutaric acid (250 mg/kg) and sodium thiosulfate (1000 mg/kg) provided an additional 48% protection against a LCT88 of HCN. A single dose of alpha-ketoglutaric acid (500 mg/kg) and sodium thiosulfate (1000 mg/kg) solutions afforded a 70% increase in survivability of the exposed animals. When mice were injected ip with 100 mg/kg of alpha-ketoglutaric acid 15 min prior to the injection of 5.5 mg/kg (LD50) of NaCN, the lethality was reduced to an LD30. Two hundred mg/kg alpha-ketoglutaric acid, challenged with the same dose of NaCN, reduced the lethality to 23%. When mice were challenged with 6.0 mg/kg of NaCN (LD70) pretreated with 100 mg/kg of alpha-ketoglutaric acid or 200 mg/kg of sodium thiosulfate, the LD was not altered in the former but reduced to an LD15 in the latter. At higher doses of sodium thiosulfate (500 mg/kg), an LD60 occurred at 13.6 mg/kg NaCN (2.5 x LD50).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1976

A technique for early Pantopaque myelography in cervical spinal cord injuries.

A simple, reliable method for early Pantopaque myelography in patients with traumatic injuries of the cervical spinal cord is presented. Myelography is accomplished with the patient prone on a Stryker frame after vertebral reduction and alignment have been achieved with axial skeletal traction. A lateral C1-2 spinal puncture and a portable ""C-arm'' image intensifier with televised fluoroscopy are used. There have been no complications and no occurrences of vertebral re-dislocation with this technique.

Humans↗
PubMed1975

The neurological deficit associated with sudden occlusion of abdominal aorta due to blunt trauma.

A review of the literature revealed five well-documented cases of abdominal aortic injury due to blunt, nonpenetrating trauma. An additional case report is offered. In all cases the level of aortic injury was at or distal to the origin of the inferior mesenteric artery. In five of these reports, including the present case, sudden traumatic occlusion of the distal abdominal aorta occurred and led to associated neurological deficit. The authors submit, based on clinical manifestations, selective angiography of spinal cord vasculature, and the operative experience of others, that these neurological deficits resulted from acute peripheral nerve ischemia and not from spinal cord ischemia as had been assumed in the past. The final neurological deficit due to acute peripheral nerve ischemia may masquerade as that seen with a "transverse" spinal cord lesion. However, the prognosis for recovery of neurological function differs markedly between the two conditions. All surviving patients experienced rapid resolution of their neurological deficits in the immediate postoperative period. Infrarenal aortic occlusion will not produce spinal cord infarction.

Abdominal Injuries↗
PubMedDate not supplied

Comparison of blood flow and patency in arterial and vein grafts to basilar artery.

Blood flow and patency rates obtained by lingual to basilar artery anastomosis were compared with those obtained by saphenous vein bypass graft from the carotid to the basilar artey in two groups of ten dogs. Flow was measured by an electromagnetic technique while blood pressure and blood gases were monitored. Graft patency also was determined by angiography and histological examination. The arterial and venous grafts carried more than enough blood to maintain a normal flow (9.5 ml per minute) through the basilar system of dogs. Immediately after anastomosis, average flow through the vein grafts was 15.5 ml per minute (range 10 to 24 ml per minute). Six weeks later, average flow through the vein graft was 11.5 ml per minute and through the arterial graft 13 ml per minute. With induced hypertension, flow increased in the arterial grafts to an average of 26.2 ml per minute and in the vein grafts 24 ml per minute. Hypercarbia increased arterial graft flow to an average of 27.8 ml per minute and vein graft flow to 23.5 ml per minute. By angiography, graft patency was shown in only 80% of the grafts at one week and in 60% at six weeks postoperatively, even though all grafts were patent by flow and histological determinations. This failure of angiography represents a limitation of the radiographical resolution in millimeter-sized vessels.

Animals↗