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Biomedical subjects

R T Jackson

Publications and source records attributed to R T Jackson.

At least 109 records · Page 6Linked to original sources
PubMed1977

Effect of inflammatory mediators on nasal mucosa.

A technique used for study of permeability and vasodilation in the middle ear has been adapted to study the response of nasal mucosa to common inflammatory mediators involved in the natural production of allergic or infectious rhinitis. All of the mediators tested (histamine, prostaglandin E1, bradykinin, the C3a fraction of complement, Escherichia coli endotoxin, and lysozyme) were found to increase nasal permeability to the isotopic tracer 99mTc as the pertechnetate ion. Histamine increased the permeability of nasal mucosa to technetium-labeled plasma protein. Results indicate that the nasal mucosa is approximately ten times as permeable to the pertechnetate ion as middle ear mucosa. Nasal mucosa was also noted to be permeable to protein, even in the absence of inflammatory mediator, in contrast to prior studies of middle ear mucosa that showed little or no permeability in the absence of inflammatory mediator. In almost all cases, a corresponding change in vasodilation accompanied permeability changes.

Animals↗
PubMed1977

Malignant neoplasms of the nasal cavities and paranasal sinuses: (a retrospective study).

This study presents a retrospective look at 115 patients evaluated here from 1957 to 1974. In this series, 57 percent were males and 43 percent females, 84 percent were Caucasian and 16 percent Negro. Lesions confined to or originating in the antrum made up 67 percent while nonantral lesions were 33 percent. Mean age at diagnosis was 59.1 years. Smoking and drinking history did not appear to be contributory. Antral lesions were retrospectively staged according to Sisson's TNM classification. Sixteen tumor types were involved, with the most common being epidermoid. Diagnosis was most often made by intranasal or Caldwell-Luc biopsy. Most frequent symptoms, as well as earliest symptoms, were nasal obstruction, localized pain, and epistaxis. Average duration of symptoms was 6.4 months. Therapy was generally in the form of radiotherapy alone, preoperative radiotherapy and surgery, surgery and postoperative radiotherapy, or surgery alone. Local recurrences occurred in 44 percent of antral lesions and 50 percent of non-antral lesions. Regional (cervical) nodal metastases developed in 25 percent of antral lesions and 11 percent of non-antral lesions. Distant metastases developed in 30 percent of antral cases and 35 percent of non-antral cases. Five-year survival was 32 percent (35 percent determinate) for the total group. The more advanced the staging of the antral lesions, the worse the prognosis. Best survival figures were in the areas of preoperative radiotherapy and surgery at 38 percent (43 percent) and surgery alone at 56 percent (59 percent).

Adolescent↗
PubMed1977

Cefoxitin activity against multiply antibiotic-resistance Klebsiella pneumoniae in vitro.

Due to the emergence of cephalothin- and gentamicin-resistant Klebsiella pneumoniae at this institution, we investigated the in vitro activity of two new cephalosporin compounds-cefoxitin and cefamandole. Whereas both drugs were active against cephalothin- and gentamicin-susceptible isolates of Klebsiella, only cefoxitin exhibited significant activity against cephalothin- and gentamicin-resistant isolates. Seventeen of 20 (85%) of the cephalothin- and gentamicin-resistant isolates were inhibited by </=12.5 mug of cefoxitin per ml. The minimum bactericidal concentration in broth of representative isolates equaled the agar dilution minimum inhibitory concentration. Kirby-Bauer disk susceptibility testing correlated well with the agar dilution minimum inhibitory concentration. Cephalothin and cefamandole resistance of isolates could be correlated with antibiotic degradation by beta-lactamase. Cephalothin and cefamandole evoked only a transient decrease in viable bacterial cell count with rapid inactivation of antibiotics, and full regrowth of the organisms. Cefoxitin, on the other hand, was quite effective in vitro against multiply resistant Klebsiella. No beta-lactamase degradation of cefoxitin was detected. Growth curves with antibiotics indicated rapid killing of cephalothin- and gentamicin-resistant isolates by cefoxitin.

Cefoxitin↗
PubMed1977

Sequential hospitalwide outbreaks of resistant Serratia and Klebsiella infections.

Late in 1973 at the Nashville Veterans Administration Hospital, an intrusion of Serratia marcescens infections that were resistant to gentamicin sulfate and other antimicrobial agents occurred. This abated somewhat, only to be superseded by another wave of multiply-resistant infections due to Klebsiella pneumoniae beginning in the spring of 1974. Approximately 400 patients had substantial infections with these organisms during the 2 1/4 year period, imposing considerable morbidity and mortality. Due to the serious and lasting impact that these events imposed on patient care in our hospital, we sought explanations for the sequential infectious outbreaks. Both may have arisen because of the same persisting pressures favoring prevalence of multidrug-resistant bacteria. Indirect evidence including the sequential order of the outbreaks, similarity of antibiotograms, transferable multiple drug resistance from Serratia to Klebsiella, and possession of approximately equal molecular weight plasmids supported the notion that the two outbreaks were causally related.

Cross Infection↗
PubMed1976

Action of inflammatory mediators on middle ear mucosa. A method for measuring permeability and swelling.

We describe a technique for measuring changes of permeability and vasodilation-edema in middle ear and Eustachian tube mucosa when this tissue is challenged with an inflammatory mediator. A ten-minute exposure to histamine, bradykinin, and prostaglandin E1 or E2 causes marked increases in permeability and a vasodilation-edema that lasts from 30 minutes to two hours. The passage across the mucosa of a small ion-pertechnetate-is increased by these mediators. Protein molecules, normally prevented from permeating the blood-mucosal barrier, permeate in substantial amounts after the middle ear mucosa is challenged with inflammatory mediators. Thus, the mediators seem capable of producing two of the cardinal signs of middle ear inflammation. They may be the proximal cause of middle ear effusions and their continued presence may be responsible for the chronic nature of this disease.

Animals↗
PubMed1975

Sinusitis of the maxillary antrum.

Twenty-four adults with clinical evidence of sinusitis were studied by 65 needle punctures of the maxillary antrum. Fourteen of 15 sinuses with normal transillumination and 19 of 26 that were dull had normal aspirates, whereas 24 of 24 that were opaque had abnormal aspirates (P less than 0.001). Marked mucosal thickening as determined radiologically (Water's view) was associated with abnormal aspirates whereas lesser mucosal thickening was not (P less than 0.001). In acute sinusitis, there was a strong correlation between high aspirate leukocyte counts (greater than 1000 per cubic millimeter) and infection as manifested by bacterial titers of greater than 10(5) per milliliter or the isolation of virus fungus (P greater than 0.001). Anterior-nasal-swab cultures correlated poorly with direct aspirate culters. Organisms frequently recovered from the sinus included Haemophilus influenzae, Strepto coccus pneumoniae, and anaerobic bacteria. Rhinovirus was recovered twice. Antibiotics were usedful in patients with acute sinusitis if the organism was sensitive in vitro (P less than 0.001).

Acute Disease↗
PubMed1975

Blood flow measurements in skin flaps.

For the last 50 years, the empirical approach of set length to width ratios for skin flaps has been held valid. Not until Milton's work in 1971 was this concept challenged. This report represents a method where precise, reproducible, and quantitative measurements of skin blood flow can be made using four radioactive nuclide microspheres and measures the blood flow changes in flaps of differing length to width ratios. Conclusions from our data suggest that the cutaneous blood flow in ventrally based, abdominal skin flaps in dogs is independent of base width as measured immediately after outlining and elevation.

Animals↗
PubMed1975

Is the vidian nerve cholinergic?

Electrical stimulation of the parasympathetic nerve (vidian) to nasal mucosa induces a nasal secretion and a nasal vasodilation. We have provided additional evidence that, in the dog and cat, the secretory mechanism can be blocked with low doses of atropine sulfate (0.01 mg/kg), but the dilation mechanism is not blocked by high doses (1 mg/kg) of atropine sulfate. By some definitions therefore, the vasodilation is not a cholinergic effect. There appears to be a basic difference in the composition of the vidian nerve in the dog and cat. In the cat, the vidian appears to have a strong sympathetic component. In the dog it does not. The human vidian nerve, according to anatomists, is more like the dog's.

Acetylcholine↗