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Biomedical subjects

R J Henry

Publications and source records attributed to R J Henry.

63 records · Page 4Linked to original sources
PubMedDate not supplied

Cardiovascular influences of nitrous oxide in spontaneously hypertensive rats.

Cardiovascularly compromised outpatients undergoing minor elective oral surgical or dental care have not frequently received the anxiolytic and analgesic benefits of nitrous oxide ostensibly because of the reported likelihood of sympathetic nervous stimulation and possible exacerbation of hypertension or cardiac complication. Recent studies, though, have shown that the hemodynamic effects of nitrous oxide are negligible and possibly even beneficial. The present study was conducted to determine the cardiovascular effects of nitrous oxide and nitrogen (as control gas) in the spontaneously hypertensive rat (SHR) and its normotensive Wistar-Kyoto counterpart (WKY). SHRs exposed to nitrogen did not exhibit any significant change in SBP or HR, but SHRs exposed to nitrous oxide exhibited a generally concentration-related reduction in both SBP and HR. WKYs, however, displayed reductions in SBP and HR when exposed to either nitrous oxide or nitrogen. These findings indicate a difference in the hemodynamic responses of SHRs and WKYs to nitrous oxide and nitrogen. The specificity and mechanism of the nitrous oxide effects in hypertension were not determined in this study, however, these findings do indicate that nitrous oxide does not exacerbate hypertension in normal or hypertensive rats.

Animals↗
PubMedDate not supplied

The glass ionomer rest-a-seal.

The "glass ionomer rest-a-seal" described is a restorative technique that minimizes removal of tooth structure and protects the glass ionomer from inherent property weaknesses. This technique would seem to have added benefits over the preventive resin restoration where pit-and-fissure decay involves dentin. Glass ionomer cements have become popular as materials with many desirable properties, including an adhesive nature and an ability to release fluoride to adjacent tooth structure. These materials are, however, technique-sensitive and proper application is critical for long-term success. Conservative treatment of pit- and fissure decay is often indicated. By utilization of the preventive resin restoration and now the glass ionomer rest-a-seal, practitioners can improve the long-term dental health of their patients.

Acid Etching, Dental↗
PubMedDate not supplied

Slow maxillary expansion: a review of quad-helix therapy during the transitional dentition.

The maxillary quad-helix appliance is a commonly used approach for treatment of maxillary arch constriction and/or posterior crossbite. Concern over excessive force generation during rapid maxillary expansion led to its development and use in growing children. The purpose of this article is to present the clinical application and therapeutic considerations regarding use of the quad-helix appliance in the slow maxillary expansion of mixed dentition cases. Considerable evidence is presented supporting such early expansion and factors for case selection are identified when considering this a treatment option.

Activator Appliances↗
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↗
PubMedDate not supplied

Dental management of children with asthma.

Asthma affects about 1 in 10 children. The condition is characterized by acute respiratory distress brought on by environmental factors. The condition is treated with medications aimed to reduce reaction to stimulants by the airway. Dental management involves attention to the status of the patient and awareness of stimulants of the reactive airway. Clinical recommendations are provided.

Acute Disease↗
PubMedDate not supplied

A pharmacokinetic study of midazolam in dogs: nasal drop vs. atomizer administration.

PURPOSE: The purpose of this investigation was to compare the pharmacokinetics of midazolam following intravenous, intranasal drop, and nasal-atomizer administration in beagle dogs. METHODS: Six animals weighing 9-13 kg were used in a repeated-measure design, group assignment based on route of drug administration. Midazolam (1.5 mg/kg) was administered with the delivery route based on group assignment. Blood samples were obtained at baseline and at 1, 3, 5, 7, 10, 15, 20, 30, and 45 min after administration. Cerebrospinal fluid samples (CSF) were obtained at 5 and 10 min after administration. Plasma and CSF concentrations of midazolam were determined by electron-capture gas-liquid chromatography. RESULTS: Comparison between groups and over time demonstrated that both nasal routes resulted in significantly higher CSF concentrations relative to corresponding plasma levels, and that nasal-atomizer administration produced significantly higher CSF concentrations compared to the drop approach.

Administration, Intranasal↗