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Biomedical subjects

J A Anderson

Publications and source records attributed to J A Anderson.

At least 145 records · Page 8Linked to original sources
PubMed1990

The effectiveness of flumazenil in reversing the sedation and amnesia produced by intravenous midazolam.

In this double-blind study 31 outpatients undergoing third molar extraction were randomly assigned to one of two groups. All patients were sedated with intravenous midazolam (IV) by titration method. The flumazenil group (n = 20) received an average of 0.8 +/- 0.17 mg of flumazenil IV. The placebo patients (n = 11) each received 10 mL of normal saline. By both observer and patient alertness ratings, patients receiving flumazenil appeared significantly more alert than placebo patients at 5, 15, 30, and 60 minutes following reversal. After reversal the flumazenil group had significantly higher scores than the placebo group at all intervals through 60 minutes. All the patients receiving flumazenil were able to walk without assistance at 5 minutes, compared with only one patient in the placebo group, and more patients in the flumazenil group recognized the picture card shown to them at 5, 15, 30, and 60 minutes postreversal. Flumazenil is effective in terminating the amnestic properties of midazolam, but this appears to occur to a lesser extent than the reversal of its sedative properties.

Amnesia↗
PubMed1990

Risk of systemic reactions in patients taking beta-blocker drugs receiving allergen immunotherapy injections.

To learn whether patients taking beta-blocker (BB) drugs were at increased risk of having systemic reactions (SRs) from allergen immunotherapy, we prospectively studied 56,105 injection visits in 3178 patients during a 1-year interval. A total of 166 SRs occurred in 144 patients (4.5% of all patients) or 3.0 SRs occurred per 1000 injection visits. Sixty-eight patients were taking BB drugs throughout the year, and only one patient had an SR. By chance, 3.08 patients were expected to have had SRs. We conclude that BB drugs did not increase the frequency of SRs in the patients studied who were receiving immunotherapy (p greater than 0.95). Patients taking BB drugs may still be at increased risk, however, from more severe SRs or their SRs may be more refractory to therapy.

Adrenergic beta-Antagonists↗
PubMed1990

Alzheimer's disease and prior therapeutic radiation exposure: a case-control study.

Few risk factors have been identified for dementing illness to date. To evaluate prior therapeutic radiation exposure as a potential risk factor for Alzheimer's disease, we carried out a retrospective case-control study using the Rochester Epidemiology Resource. Cases were all incident cases of AD from 1960 through 1974 (N = 392) identified in an ongoing study of the condition in this community. One age- and sex-matched control for each case was selected from all registrations for care during the year of onset in the case. There were 86 cases and 89 controls with prior radiation exposure, and the variable used to describe exposure was absorbed dose. Most of the exposure was small doses: 11 individuals received greater than 1,000 centigray (3 cases, 8 controls). Using the logistic regression methods of Breslow and Day, the estimated odds ratio for any prior therapeutic radiation exposure was 0.95 (95% CI, 0.66 to 1.37). When the exposure variable was limited to head exposure only, the odds ratio was 0.65 (95% CI, 0.32 to 1.31). It is unlikely that the risk associated with therapeutic radiation in the development of Alzheimer's disease is greater than 1.4.

Aged↗
PubMed1990

Recombinant enkephalinase effectively inhibits substance P-induced miosis in the rabbit eye cup model.

Enkephalinase (EC 3.4.24.11) is a naturally occurring, membrane-bound peptidase that degrades substance P in vivo and in vitro. Addition of this neutral endopeptidase to a rabbit eye cup model partially inhibits substance P-induced contraction of the iris sphincter muscle. Inactivation of substance P is reversed by thiorphan, a specific inhibitor of enkephalinase. These results show that enkephalinase degradation of substance P produces metabolites that are physiologically inactive in iris contraction. We also observed that atropine acts synergistically with enkephalinase to completely abolish substance P-induced iris contraction suggesting that the action of substance P on the iris contains an acetylcholine-stimulatory effect which is not lost by enkephalinase treatment.

Animals↗
PubMed1990

Serum promotes asbestos-induced injury to human pulmonary epithelial cells.

Asbestos exposure causes chronic interstitial pulmonary fibrosis. Injury to human pulmonary epithelial cells (HPEC) is speculated to precede the fibrotic response. We investigated whether asbestos, either alone or in conjunction with serum, injured cultured HPEC as assessed in a standard chromium 51 release assay. Amosite asbestos in serum-free media induced modest HPEC injury (9.4% +/- 3.3% Cr release), which was significantly enhanced (2.7-fold) in the presence of serum (25.5% +/- 4% Cr release). HPEC cytotoxicity was both asbestos and serum dose-dependent. Additionally, we demonstrated that, compared with HPEC injury induced by asbestos plus serum, (1) heat-decomplemented serum or serum fractions of a wide range of molecular weights were equipotent to fresh serum, (2) catalase, superoxide dismutase, or dimethylthiourea was not protective, (3) 3-aminobenzamide, which prevents oxidant-induced adenosine triphosphate depletion by inhibiting poly-adenosine diphosphate-ribose polymerase, afforded significant protection (32% decrease in HPEC injury), and (4) deferoxamine-treated asbestos was significantly less toxic to HPEC compared with untreated asbestos, causing a 57% decrease in HPEC cytotoxicity. Electron microscopic studies revealed that, compared with buffer, serum increased the amount of amosite asbestos along the surface and inside HPEC. Thus, amosite asbestos is cytotoxic to cultured HPEC and serum promotes this injurious effect by augmenting the interaction of asbestos with HPEC. These data suggest that this effect may occur by increasing intracellular oxidant stress mediated in part by the iron in asbestos.

Asbestos↗
PubMed1989

Conscious sedation.

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Anesthesia, Dental↗
PubMed1989

An investigation of capnography and pulse oximetry as monitors of pediatric patients sedated for dental treatment.

Traditional methods of monitoring sedated pediatric dental patients have major shortcomings. This study evaluated the use of capnography in conjunction with pulse oximetry for monitoring children during conscious sedation for dental treatment. The specific purposes of the study were to determine if capnography would: (1) detect ventilatory changes that subsequently cause an oxyhemoglobin desaturation as detected by pulse oximetry; and (2) detect an airway obstruction. Ten pediatric dental patients (mean age 2 years, 10 months) were sedated with 75 mg/kg of chloral hydrate in strict accordance with the Guidelines for the Elective Use of Conscious Sedation, Deep Sedation, and General Anesthesia in Pediatric Patients of the American Academy of Pediatric Dentistry and the American Academy of Pediatrics (1985). All patients were monitored continuously using both capnography and pulse oximetry. Analysis of data obtained using these monitors revealed that specific end-tidal CO2 values were not predictive for subsequent oxyhemoglobin desaturations and that capnography was very accurate in detecting complete obstruction of the airway. Pulse oximetry revealed that all patients had mild oxyhemoglobin desaturations and that 50% had moderate desaturations.

Anesthesia, Dental↗
PubMed1989

Nuclear magnetic resonance microscopic ocular imaging for the detection of early-stage cataract.

A nuclear magnetic resonance (NMR) microscopic ocular imaging was performed at 7.0 Tesla to investigate its usefulness in the detection of early-stage cataracts. For this study, galactose cataracts were generated in experimental rabbits through diet (35% galactose), and enucleated eyes were imaged at various times after initiation of the diet. In previous studies using a 0.6 Tesla conventional magnetic resonance imager (MRI), the contrast between normal and cataractous tissues in the lens was not well defined, mainly due to the partial volume effect coming from the limitation of resolution and signal-to-noise ratio (SNR). With resolution of 60 X 60 X 80 microns, early localized precataractous tissue changes were clearly observed after 5 days diet. Precataractous tissue changes were seen histologically but no visible evidence of lens change was detected by the conventional slit lamp biomicroscope at this time. Substantially elongated spin-spin relaxation times (T2) in localized cataractous tissues (72.4 +/- 8.8 msec) were consistently observed compared with those in normal lens region (16.1 +/- 3.2 msec); however, the changes of the spin-lattice relaxation time (T1) were not significant. Some ocular NMR microscopic images with corresponding histological photographs are demonstrated to show the potential of NMR microscopy.

Animals↗
PubMed1989

Therapeutic radiation and hyperparathyroidism. A case-control study in Rochester, Minn.

A case-control study was conducted among residents of Rochester, Minn, to assess the influence of prior therapeutic radiation on the risk of primary hyperparathyroidism. Fifty-one cases of surgically proven primary hyperparathyroidism diagnosed from 1975 through 1983 were each matched by age and gender to two control subjects, with radiation exposure documented through preexisting medical records. The overall odds ratio for any prior therapeutic radiation therapy was 1.9 (95% confidence interval, 0.9 to 4.4) and it was 2.3 (95% confidence interval, 0.9 to 5.7) when limited to those with prior head and neck radiation. Among women, the figures were 2.9 (95% confidence interval, 1.1 to 7.5) for any prior therapeutic radiation and 3.4 (95% confidence interval, 1.2 to 10.2) for head and neck exposure. This study confirms the association between primary hyperparathyroidism and prior therapeutic radiation exposure, at least for women in this population.

Adenoma↗
PubMed1988

Multiple dosing increases the ocular bioavailability of topically administered flurbiprofen.

The ocular bioavailability of radiolabeled flurbiprofen was determined after single or multiple topical dosing of rabbits. Three doses at half-hour intervals of a 0.03% solution produced higher concentrations in the tissues than those after a single dose of either the 0.03% or the 0.1% solution. Three doses of 0.03% flurbiprofen gave intraocular concentrations in the range that inhibits cyclo-oxygenase activity. Administration of more than three doses did not significantly increase the concentration of flurbiprofen in most tissues. The drug distribution pattern in the ocular tissues after multiple dosing was the same as after single dosing. Although multiple dosing with the 0.03% concentration resulted in higher tissue levels of flurbiprofen, increasing the concentration to 0.1% did not result in greater ocular bioavailability of the drug.

Animals↗
PubMed1988

Polymorphic reticulosis limited to the upper aerodigestive tract--natural history and radiotherapeutic considerations.

Polymorphic reticulosis (PMR) is a specific clinicopathological entity which commonly presents as an aggressive, necrotizing lesion of the upper airway. It is a separate nosologic entity from Wegener's granulomatosis, though its site and aggressive nature has lead to confusion in the distinction between these two different processes. Although radiotherapy has been acknowledged as the treatment of choice for limited upper airway PMR, little data exist to guide the radiation oncologist in the practical management of this disorder. We review our single institutional experience with PMR limited to the upper airway. Thirty-four patients (24 males, 10 females) with a median age of 44 years (range 19-80 years) are presented. Symptoms of nasal obstruction were present in 94%. Systemic symptoms such as fever, night sweats, and weight loss were noted in 62% and were often striking clinically. The nasal mucosa was most frequently involved (91%), although involvement of the paranasal sinuses (47%), palate (32%), as well as, other upper airway sites was not uncommon. Perforation of involved structures was recorded in 37%. All but 1 patient were treated with primary radiotherapy. Twelve relapsed with PMR and 3 additional patients manifested diffuse histiocytic lymphoma either within or adjacent to the original treatment field. The median survival relapse in these 15 patients was only 4 months, although 25% were salvaged at 5 years post-relapse. The overwhelming majority of relapses were noted within the first 3 years following treatment. An evaluation of radiotherapy parameters indicated that a minimum dose of 42 Gy or a TDF of 70 is necessary to achieve long-term local control. Pattern of failure analysis demonstrated in-field failure as the predominant failure site, and this problem should become much less significant with implementation of proper time-dose-fractionation schemes. Marginal failure was noted in 20% as a component of eventual failure sites suggesting the need for generous treatment volumes including clinically uninvolved adjacent structures at risk, such as palate, sinuses, and nasopharynx for nasal lesions. Finally, systemic failure occurred in 25%. Although this rate may be reduced by improved local treatment measures, ultimately effective systemic chemotherapy will be required to substantially impact on these patients' survival.

Adult↗