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Biomedical subjects

G F Anderson

Publications and source records attributed to G F Anderson.

At least 145 records · Page 8Linked to original sources
PubMed1980

An improved method of wound management for pediatric patients.

Polyurethane moisture-vapor permeable film (MVPF), a new product for the management of superficial wounds, was studied in an uncontrolled clinical trial in 50 pediatric patients. MVPF was used in the management of skin graft donor sites, partial thickness burns, traumatic abrasions, decubitus ulcers, intravenous skin sloughs, and a variety of other wounds. Advantages of this material over standard dressing techniques include: more comfort, freedom of motion of the injured part, fewer dressing changes, and apparently faster epithelialization in many cases. Folliculitis, noted in one patient, was the only complication. MVPF is easily adaptable to outpatient wound management, and has gained rapid acceptance by nurses, patients and parents.

Bandages↗
PubMed1980

Hormonal enhancement of technetium-99m pertechnetate uptake in experimental Meckel's diverticulum.

A canine model simulating Meckel's diverticulum was used to evaluate the effects of pentagastrin, glucagon, and a combination of the two hormones on the gastrointestinal localization of 99mTc. Pentagastrin produced accelerated uptake of the radionuclide in both the stomach and the ectopic gastric mucosa but resulted in early visualization of the duodenum and a "washout" effect on the radioisotope within the Meckel's diverticulum. Glucagon provided prolonged retention of the radionuclide in the stomach and ectopic mucosa and prevented duodenal visualization. A combination of both hormones produced increased activity in the stomach and experimental Meckel's and decreased duodenal filling. This enhanced target to background contrast and provided improved visualization of the ectopic gastric mucosa.

Animals↗
PubMed1979

Comparison of the urinary bladder base and detrusor to cholinergic and histaminergic receptor activation in the rabbit.

The effects of cholinergic and histaminergic agonists and antagonists on the receptor responsiveness of the bladder as well as the fundus were compared. Carbachol and histamine were more potent and generated a greater force of contraction in the detrusor muscle than in the neck region. Histamine characteristically produced a rapid twitch-like contraction followed by an increase in motility in the neck smooth muscle while it produced an increased sustained contraction similarly induced by carbachol in the detrusor preparation. Pyrilamine was equally effective in competitively blocking histamine response in both the detrusor and neck preparations. We conclude that the bladder neck, like the detrusor regions, has cholinergic and H1 histaminergic receptors.

Animals↗
PubMed1978

Comparative in vitro effects of imipramine, oxybutynin, and flavoxate on rabbit detrusor.

The ability of imipramine, oxybutynin, and flavoxate to antagonize carbamylcholine and barium chloride (BaCl2)-induced contractions of rabbit detrusor, and to block impulse conduction in desheathed frog sciatic nerves has been assessed in vitro. Impiramine exerts noncompetitive carbamylcholine and BaCl2 blockade by 10(-5) M and a local anesthetic effect equipotent with that of tetracaine. Oxybutynin exerts a strong competitive antagonism of carbamylcholine by 10(-8) M, a noncompetitive antagonism of BaCl2 equivalent to that of imipramine, and moderate local anesthetic activity. Flavoxate, under these experimental conditions exerts little anticholinergic, antispasmodis, or local anesthetic activity. Imipramine and oxybutynin thus demonstrate a number of smooth muscle effects by which their therapeutic actions may be exerted. The mechanisms of action of flavoxate remain obscure.

Anesthetics, Local↗
PubMed1978

Interactions of calcium, prostaglandins and indomethacin on the smooth muscle of the bladder.

The effects of prostaglandin (PG) E2, PGF2alpha and indomethacin (Indo) were studied on isolated detrusor smooth muscle strips in balanced salt solution and in 80 mMK+ depolarizing solution. The addition of Indo to the smooth muscle preparation at concentrations of 0.1 to 1.0 micronM produced depression of spontaneous motility that was partially antagonized by PGE2 or by elevating the extracellular Ca2+ level. Alone, both PGE2 and Ca2+ caused a marked increase in motility, increasing both frequency and amplitude. In low Ca2+, K+ depolarized bathing medium with 0.1 mM EGTA added PGE2 or PGF2alpha augmented Ca2+ contractures both in velocity and amplitude while either PG without Ca2+ had no effect on the smooth muscle. Indo produced a noncompetitive antagonism of the Ca2+ dose response curve in 80 mM K+ depolarized preparations suggesting a direct effect on Ca2+ flux. Also Indo depressed both PG and Ca2+ contractures in terms of velocity and magnitude, suggesting that Indo may act at Ca2+ channels in addition to its action on PG synthetase. These data support the work of others who suggest that PGs may augment Ca2+ permeability, acting at the Ca2+ channel or as a carrier for Ca2+ across smooth muscle cell membranes.

Animals↗
PubMed1977

Characterization of the oxybutynin antagonism of drug-induced spasms in detrusor.

Oxybutynin chloride exerts a moderate anticholinergic effect on rabbit detrusor in vitro, which is reversible and competitive in nature (KB = 4.7 x 10(-9), and midway in potency between atropine and papaverine. In addition, oxybutynin strongly antagonizes BaCl2-induced spasms of detrusor with a potency equivalent to that of papaverine and 10 times that of atropine. This musculotropic spasmolytic effect is slightly greater in rabbit than human or monkey tissue, and noncompetitive (pD2 = 5.5). This direct relaxant effect, unlike that of papaverine, is not mediated by the inhibition of tissue phosphodiesterase, but probably reflects oxybutynin's local anesthetic properties and associated effects on Ca++ fluxes and binding.

Animals↗
PubMed1977

Control of ureteral peristalsis during changes in intravesical pressure.

Studies of the ureteral response to changes in intravesical pressure (IP) have been conducted by surgically altering the neural and hydrodynamic integrity of canine ureters. Ureteral function was assessed by acute and chronic recordings of ongoing electrical activity. Intact control ureters responded (acute to 56 per cent; chronic to 83 per cent) to elevated IP with immediate increases and to decreases in IP with slowing or cessation of activity. Acute ureteral ligation mimicked the effects of increased IP, except the responses were much slower. Ureterotomy and the resultant extravasation of urine did not alter the ureteral response. Disruption of renal nerves, whether by selective sectioning or by nephrectomy, was associated with exaggerated ureteral frequency responses which were delayed in onset. Ureters lacking neural connections with the bladder responded with bursts of multiple spikes and increases in the force of peristalsis. These observations are discussed in terms of the myogenic and neurogenic control of ureteral peristalsis.

Animals↗
PubMed1975

A study of the anticholinergic and antispasmodic activity of oxybutynin (Ditropan) on rabbit detrusor.

Experiments have been conducted which show that while the tertiary amine oxybutynin has only moderate in vitro anticholinergic and antihistaminic activity, it is a potent inhibitor of barium chloride-induced spasms of rabbit detrusor muscle. Oxybutynin exerts 1/13 the anticholinergic activity of propantheline and 1/4 that of atropine, but produces approximately 2x the inhibition of barium chloride-induced spasm than propantheline and 10x the inhibition produced by atropine. In sum, oxybutynin possesses a notable antispasmodic activity distinct from its anticholinergic activity and stronger than that of atropine, propantheline, or methantheline, which may prove useful in the treatment of smooth muscle hypermotility.

Animals↗