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Biomedical subjects

J A Anderson

Publications and source records attributed to J A Anderson.

At least 19 recordsLinked to original sources
PubMed1992

Esmolol is more effective than sodium nitroprusside in reducing blood loss during orthognathic surgery.

The goal of this study was to compare the efficacy of esmolol and sodium nitroprusside (SNP) as primary drugs for producing controlled hypotension and limiting blood loss during orthognathic surgery. Thirty ASA physical status I and II patients (mean age 22 yr) undergoing LeFort I maxillary osteotomies were randomly assigned to receive either esmolol (n = 15) or SNP (n = 15) as the primary drug to induce hypotension. All patients received a balanced anesthetic technique including isoflurane, with controlled hypotension during the downfracture of the maxilla. Patients assigned to the esmolol treatment group received boluses of 500 micrograms/kg of esmolol, followed by a continuous infusion of 100-300 micrograms.kg-1.min-1, and the SNP treatment group received a continuous infusion of SNP at 0.25-4.00 micrograms.kg-1.min-1; both infusions were titrated to obtain a mean arterial blood pressure within the target range of 55-65 mm Hg. The mean arterial blood pressure during the hypotensive period was 58.7 +/- 0.7 (mean +/- SEM) and 61.8 +/- 0.4 mm Hg for esmolol and SNP, respectively (P less than 0.001). In addition, 40% +/- 4% of the observed values in the esmolol group and 53% +/- 3% in the SNP group were outside the target range for mean arterial blood pressure (difference significant at P less than 0.05), and a greater proportion of the deviations were above 65 mm Hg in the SNP group than in the esmolol group (0.64 vs 0.46, respectively, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Prevalence of RAS oncogene mutation in head and neck carcinomas.

RAS genes encode for a protein (p21) known to play an important role in the regulation of normal signal transduction and cell growth. Activation of RAS genes have been strongly implicated in the pathogenesis of cancer in cell line studies, animal models and in human tumors. RAS genes have been shown to be mutated in 10 to 15% of human solid tumors but the frequency of mutation varies widely depending on the tumor type. The prevalence of RAS mutation has not been well-established in head and neck squamous cell carcinomas (SCC). The purpose of our study was to screen a relatively large number (50) SCC tumors using a gene amplification technique, the polymerase chain reaction (PCR). H-RAS gene mutation is identified by diagnostic restriction length polymorphism, created by introducing specific mismatched primers in the PCR. The first 20 tumors were also amplified and directly sequenced for K-RAS codon 12 and 13. Four of the 50 screened tumors were positive for H-RAS codon 12 mutation. All tumor DNA screened normal at codon 61 and the first 20 tumors were also normal at K-RAS codon 12 and 13. The prevalence of RAS mutations appears to be low in head and neck squamous cell carcinomas. Tumors positive for point mutation in the H-RAS gene revealed some unusual clinical characteristics.

Adult↗
PubMed1992

Evaluation of tear protein deposits on contact lenses from patients with and without giant papillary conjunctivitis.

Giant papillary conjunctivitis (GPC) associated with contact lens wear is believed to result from an irritative or allergic response to accumulated lens surface deposits. In a masked study, contact lenses worn short-term (2 weeks or less) or long-term (2-12 months), and obtained from patients with and without active GPC, were examined for deposited proteins: IgA, IgE, IgG, IgM, lactoferrin, and lysozyme. Using immunohistochemical methods lenses were separately graded on a 4+ scale for extent of protein coverage. All lenses showed substantial deposits (averaging 50-75% lens coverage) of the normal tear proteins, with the exception of IgE which averaged less than 25% lens coverage; maximum protein deposition was apparent on lenses worn for only 3 days. Both symptomatic and asymptomatic persons deposited similar amounts of the common tear proteins on their contact lenses, with the exception of IgM. A statistically significant increase in IgM deposition was found when the short-term GPC lenses were compared to short-term asymptomatic lenses. Our data suggest that the development of GPC does not depend on amount of deposition of the normal tear proteins IgA, IgG, IgE, lactoferrin or lysozyme. Differences observed in IgM deposition may reflect an immune response in GPC.

Conjunctivitis, Allergic↗
PubMed1979

Intraocular penetration of topically applied lincomycin hydrochloride in rabbits.

Ocular penetration of lincomycin hydrochloride in albino rabbits was determined by bioassay. On topical application, the frequency of multiple instillation of drops played an important role in producing therapeutic levels in the anterior chambers. Therapeutic levels were attained in the cornea, aqueous humor, and iris-ciliary body, with peak values occurring at 30 to 45 minutes. Varying the pH of the dosing solution did not change ocular absorption and distribution substantially. Removal of corneal epithelium, however, greatly enhanced absorption. Relative to clindamycin, lincomycin hydrochloride had longer onset of peak values and lower overall concentration in ocular tissues. Intravitreous injection of lincomycin hydrochloride produced therapeutic and steady levels of antibiotic in anterior chambers. Injection produced a concentration in aqueous humor twice that achievable topically. The major route of elimination from the posterior chamber was through retina-choroid.

Administration, Topical↗
PubMed1979

Inhibition of mitogen induced blast transformation by a multiple sclerosis serum factor.

A factor in the sera of multiple sclerosis patients inhibits RNA, protein and DNA synthesis in actively metabolizing mitogen stimulated lymphocytes. Inhibition of macromolecular synthesis precedes cell death by 24 to 36 hours. The factor is effective on cells which are already committed to transformation by previous exposure to mitogen and cells which are simultaneously exposed to the factor and mitogen. Previous exposure of unstimulated cells to the factor does not alter their subsequent response to mitogen. The factor does not inhibit RNA synthesis of unstimulated lymphocytes isolated on a Ficoll-Hypaque gradient, nor is it toxic to these cells.

Biological Products↗
PubMed1978

Naproxen in the treatment of rheumatoid arthritis.

Naproxen, a new nonsteroidal anti-inflammatory analgesic drug was found to be better than placebo and as effective as indomethacin in the treatment of rheumatoid arthritis. The drug was well tolerated, and appears to be a useful alternative to more established medication such as aspirin.

Arthritis, Rheumatoid↗
PubMed1978

Developing and maintaining social interaction in profoundly retarded young males.

Social interaction was increased in five profoundly retarded males using formal training, stimulus control, and rewarded generalization procedures. Seven behaviors were monitored for each boy to determine whether correlated changes occurred in maladaptive behaviors as social interaction varied over the several phases of a withdrawal design that included multiple-baseline features. All five boys increased their social interaction and reduced unoccupied and self-stimulatory behavior. These changes were maintained as continuous reinforcement was reduced to a single response-contingent reinforcer per 15-minute session. Four follow-up probes showed the stability of the changes.

Adolescent↗
PubMed1978

Variations in the lung size of children in Papua New Guinea: genetic and environmental factors.

In Papua New Guinea, rural village children of both sexes living in the highlands (1500--2000 m) were found to have mean values of forced vital capacity 27 per cent greater than children at sea level. Urban children with an apparently lower level of habitual activity had a lung size similar to that of rural children living at the same altitude. In a number of healthy children of coastal parents reared in the highlands and of highland parents reared on the coast, the size of the lung was, in general, appropriate for the altitude rather than for the parentage. These findings suggest that the highland--coastal difference is probably environmental rather than genetic in origin.

Adolescent↗
PubMed1978

Malignant pyoderma.

A patient is described who developed multiple areas of inflammatory pyoderma on the face, leading to extensive ulceration. Repeated investigations failed to demonstrate any specific bacteria or fungus responsible and trials of treatment with various antibiotics proved unsuccessful. Histology revealed a granulomatous abscess-like lesion, and the condition resembled what has been described as malignant pyoderma. The patient was successfully treated with oral dapsone and intralesional steroids.

Dapsone↗