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Biomedical subjects

A M Henderson

Publications and source records attributed to A M Henderson.

12 recordsLinked to original sources

3-Methoxybutylcyanoacrylate: evaluation of biocompatibility and bioresorption.

The biocompatibility and bioresorption of 3-methoxybutylcyanoacrylate (MBCA) was evaluated in vivo using female Wistar albino rats. MBCA was found to elicit slight to moderate tissue reaction similar to isobutylcyanoacrylate (iBCA) which has been sold commercially as a surgical adhesive (Bucrylate, Ethicon). MBCA was judged less reactive to tissue than ethylcyanoacrylate (ECA). The MBCA implants in rat gluteal muscles also resorbed within approx. 16 wk while iBCA implants remained essentially unchanged at 36 wk in vivo. In vitro resorption in phosphate buffer (pH 7.2) at 37 degrees C showed the same trend. The MBCA performed similarly to iBCA as a haemostat on excised rat livers and as an adhesive on rat skin incisions and had comparable adhesive bond strength.

Absorption

An assessment of postoperative oxygen therapy in patients with fractured neck of femur.

Arterial oxygen tension was studied in sixty patients with fractured neck of femur. The mean preoperative arterial oxygen tension was 63.7 mmHg (SD 12.8). Half of the patients received nasal oxygen for five days postoperatively. In these patients, mean arterial oxygen tension was greater at all times than preoperative values, and exceeded values in those not receiving oxygen in whom no change in oxygen tension occurred until an increase on the fifth postoperative day.

Aged

Inspired oxygen and nitrous oxide concentrations in volunteers during nitrous oxide sedation with a Hudson mask.

Ten volunteers were given varying ratios of oxygen and nitrous oxide at 4, 6 and 8 litres per minute using a Hudson mask delivery system. Maximum and minimum inspired oxygen concentrations, maximum inspired nitrous oxide concentrations and end tidal carbon dioxide concentrations were measured using the Datex Cardiocap CCI-104 monitor. Although pharyngeal oxygen fraction varies with the Hudson mask because the inspiratory flow exceeds the entrainment of the mask by a variable amount during much of the cycle, at 8 litres/minute flow with a ratio of 3 to 5, oxygen to nitrous oxide, safe levels of oxygen were delivered (range of means 26-31%) with basal nitrous oxide levels (mean maximum inspired N2O, 34%). When nitrous oxide sedation is used clinically, nitrous oxide must be used with consideration of safe oxygen levels. This study did not detect unsafe pharyngeal oxygen levels in the ratios investigated, where the maximum delivered nitrous oxide concentration was 75%.

Humans

Endoscopic cleaning and disinfection procedures for preventing iatrogenic spread of human immunodeficiency virus.

With estimates as high as 1.8 million individuals infected with human immunodeficiency virus (HIV) in the United States, the majority asymptomatic, it is crucial that all physicians routinely use adequate disinfection procedures for medical instruments. The protosigmoidoscopic disinfection procedures used by US family physicians were evaluated for adequacy in inactivating HIV. Sixty-seven percent of 1,585 randomly selected American Academy of Family Physicians members completed a mail survey regarding these procedures. Comparing procedures used with those recommended by the Centers for Disease Control or documented to inactivate HIV, 32.4 percent were judged to be appropriate procedures; 54.4 percent of the procedures were not tested or recommended; and 13.2 percent used appropriate solutions but at inadequate concentrations or exposure times. Therefore, a substantial proportion of US family physicians performing endoscopic procedures use disinfection procedures that may not inactivate HIV. The ever-increasing prevalence of HIV demands that standardized adequate disinfection procedures be implemented by all physicians to prevent the potential nosocomial spread of HIV.

Acquired Immunodeficiency Syndrome

Non-carious interproximal grooves in Arikara Indian dentitions.

The dentitions of adult Arikara Indians from the Larson site (39WW2) were examined to determine the frequency and etiology of noncarious interproximal grooves. The observations included groove morphology, loci and association with dental pathology. Approximately 30% of the individuals exhibit one or more pronounced grooves. The use of dental probes in conjunction with dietary grit is the likely responsible for interproximal grooves in this population sample.

Anthropology, Physical

Multivariate dental allometry in primates.

Disagreement is current over the question of whether relatively large teeth in some large primates are a natural outcome of growth trends instead of an indication of intrinsic differences. A cross-primate survey of dental scaling relative to skull (and inferred body) size is given in this study, using a principal component technique to measure the multivariate growth relation between two sets of data: dental size and cranial size. Cheek teeth are strongly positively allometric in restriced taxonomic groups, especially in cercopithecoids. Conversely, the allometry drops to an almost linear proportional growth relation when variation in diet is controlled.

Animals

Dental field theory: an application to primate evolution.

A major complicating factor in using dental data in analyses of taxonomic and evolutionary problems is the existence of morphogenetic fields. Efforts are made to abstract tooth crown size morphogenetic fields of the orangutan. The utility of coefficients of variability and factor analysis, to this end, is presented. Resulting morphogenetic dental crown size fields are described and related to hominoid dental evolution.

Animals