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Biomedical subjects

D J Jones

Publications and source records attributed to D J Jones.

184 records · Page 11Linked to original sources
PubMedDate not supplied

Bupivacaine and other amide local anesthetics inhibit the hydrolysis of chloroprocaine by human serum.

The rate of hydrolysis of chloroprocaine by human serum was studied in the presence and absence of a number of aminde local anesthetics and their metabolites. Bupivacaine (2.4 microgram/ml) and etidocaine (2.3 microgram/ml) caused 38% and 21% inhibition respectively of the rate of chloroprocaine hydrolysis. Circulating concentrations of these drugs have been reported in this range by several investigators following epidural doses of 150 to 400 mg of either drug. Mepivacaine, lidocaine, and two lidocaine metabolites (glycine xylidide and monoethylglycine xylidide) were only inhibitory at levels much greater than those seen in blood following the usual local anesthetic doses of the parent compounds. Since serum is an important site of chloroprocaine metabolism in man, the probability of chloroprocaine intoxication may be increased when it is administered with local anesthetics such as bupivacaine and etidocaine.

Anesthetics, Local↗
PubMedDate not supplied

Environmental microbial challenges to an aseptic Blow-Fill-Seal process--a practical study.

A Blow-Fill-Seal machine, set to aseptically fill sterile liquid TSB medium into 20 ml plastic containers, was subjected to a series of environmental microbial challenges in order to evaluate the effects of the room environment, and of the actions of persons in the room, on the sterility of the product. Despite a series of relatively severe stresses to the system, none of the units filled (approximately 44,000) were found, following incubation, to display growth.

Air Microbiology↗
PubMedDate not supplied

The influence of midazolam and nitrous oxide on respiratory depression in laboratory rats.

Midazolam in combination with nitrous oxide (N2O) is a commonly used sedative approach for pediatric dental patients. Respiratory morbidity and mortality have been reported with midazolam administration, particularly when used in combination with other drugs in the absence of supplemental oxygen. Thus, the purpose of this investigation was to determine the effect of midazolam alone and in combination with N2O on respiration in laboratory rats by measuring arterial blood gas levels. Sixty-four Sprague-Dawley rats, weighing 250-320 g, were assigned to one of eight groups (eight per group). Groups were allocated based upon the dosage of midazolam administered (0, 1.0, 2.0 or 4.0 mg/kg i.p.) and exposure to N2O/02 (50%/50%) or room air. Arterial blood was obtained from a femoral artery catheter and pH, O2, CO2 (mm Hg), and oxygen saturation (%) were determined. Samples were analyzed using a System 1306 pH/Blood Gas Analyzer. Baseline arterial blood gasses were obtained for each animal and at 15-min intervals following midazolam administration throughout the 45-min experiment. Following midazolam administration, animals were placed into a sealed chamber through which flowed either N2O or room air. Group comparisons demonstrated that: 1) arterial CO2 levels increased in midazolam-exposed animals breathing room air, but not in those exposed to N2O (P < 0.05), and 2) as expected, N2O/O2-exposed animals showed an increase in arterial O2 and a %saturation that was not observed in room air groups (P < 0.01). This investigation demonstrated that coadministration of N2O/O to midazolam-exposed animals did not result in hypercarbia, an early indicator of respiratory depression.

Anesthetics, Combined↗