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Biomedical subjects

R A Elliott

Publications and source records attributed to R A Elliott.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effect of treatment with calcium antagonists in vitro and in vivo on the contractile response of isolated rat and human detrusor muscle.

1. The effect of calcium antagonists on the contractile response of human and rat isolated detrusor muscle in vitro was investigated. The effect of treatment with nimodipine on rat detrusor muscle in vivo was also examined. 2. Nimodipine 0.1 mumol/l, nifedipine 0.1 mumol/l, nifedipine 0.25 mumol/l and verapamil 1.5 mumol/l reduced the maximum contractile response of isolated human detrusor muscle to carbachol by 42%, 35%, 41% and 28% respectively (P < 0.01). Verapamil 0.1 mumol/l had no significant effect on contractile response. 3. Nimodipine 0.1 mumol/l reduced the maximum contractile response of isolated rat detrusor muscle in vitro to electrical field stimulation and carbachol by 53% and 84% respectively (P < 0.01). 4. Rats were pretreated with nimodipine for 8 days (5 mg day-1 kg-1) or with a single dose. Serum nimodipine concentrations were higher in rats treated for 8 days. In rats treated with nimodipine for 8 days there was no significant difference in detrusor contractile response compared with controls. However, after one dose of nimodipine the maximum contractile response was significantly reduced compared with controls (P < 0.05). 5. At the concentrations studied, nimodipine had a greater inhibitory effect on the contractile response of isolated human detrusor muscle. Nimodipine significantly reduced the contractile response of rat detrusor muscle in vitro and after a single dose in vivo, but had no significant effect after 8 days' treatment in vivo. It is possible that chronic oral treatment with nimodipine caused an up-regulation of 1,4-dihydropyridine-sensitive calcium channels, which may explain the lack of clinical effect of chronic treatment with calcium antagonists in patients with detrusor instability.

Animals↗
PubMed1994

Effect of progestogens and oestrogens on the contractile response of rat detrusor muscle to electrical field stimulation.

1. The effect of oestradiol and progesterone pretreatment on the contractile response of isolated rat detrusor muscle to electrical field stimulation was investigated. The response to direct administration of 2 mumol/l progesterone and 2 mumol/l diethylstilboestrol in the organ bath was also examined. 2. Virgin female Wistar rats were injected subcutaneously with oestradiol benzoate (150 micrograms/kg) for 3 days followed by 1 day of progesterone (160 micrograms/kg). This cycle was repeated once. Control rats received no injections. 3. In controls, progesterone significantly reduced the maximum contractile response of rat detrusor muscle in vitro by 12% (P < 0.01). The EF50 was significantly increased compared with control. When 2 mumol/l diethylstilboestrol, was added, the maximum contractile response was significantly reduced by 42% (P < 0.01) and the frequency-response curve showed a further increase in EF50. 4. Progesterone had no effect on the atropine-resistant component of electrical field stimulation, but progesterone and diethylstilboestrol reduced the atropine-resistant response by 16% (P < 0.01). 5. Detrusor muscle from pretreated rats showed a non-significant increase in maximum contractile response compared with untreated controls. The addition of 2 mumol/l progesterone to the bath chamber had no effect on this response, but the further addition of 2 mumol/l diethylstilboestrol reduced the maximum contraction. 6. Pretreatment with oestradiol and progesterone had no effect on the atropine- or tetrodotoxin-sensitive response to electrical field stimulation. 7. In conclusion, the direct effect of progesterone and diethylstilboestrol inhibited the contractile response of detrusor muscle to electrical field stimulation and the effects of each summated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

The direct effects of diethylstilboestrol and nifedipine on the contractile responses of isolated human and rat detrusor muscles.

We have studied the direct effect of 2 mumol.l-1 diethylstilboestrol on isolated rat and human detrusor muscles. Diethylstilboestrol significantly reduced the amplitude of the contractile response of rat detrusor muscle to stimulation with acetylcholine, carbachol, electrical field stimulation, and 5-hydroxytryptamine. In isolated human bladder it also significantly reduced contractions stimulated with acetylcholine, carbachol, and electrical field stimulation. In depolarized rat detrusor muscle stimulated with different concentrations of calcium ions, the contractile responses were significantly reduced by the addition of diethylstilboestrol. Diethylstilboestrol also significantly reduced the amplitude of contractile response to potassium chloride. The inhibitory action of diethylstilboestrol was enhanced by the reduction of extracellular calcium ions, the maximum contractile response to acetylcholine, carbachol, and electrical field stimulation being reduced by a further 32%, 23%, and 45% respectively. Diethylstilboestrol did not have a significant effect on carbachol-induced contractions in depolarized rat detrusor muscle suspended in a calcium-free environment. Diethylstilboestrol was effective in blocking rat and human detrusor muscle contraction. The likely mechanism is a reduction of the influx of calcium ions into the cell during contraction rather than an effect on intracellular calcium release. These results give support for treating incontinent patients with drugs that block calcium ion uptake, and may suggest a further beneficial effect of oestrogen therapy in postmenopausal women.

Acetylcholine↗
PubMed1992

The effect of in vivo oestrogen pretreatment on the contractile response of rat isolated detrusor muscle.

1. The effect of oestradiol pretreatment was investigated on the response of rat isolated detrusor muscle to cholinergic, electrical and 5-hydroxytryptamine (5-HT) stimulation with and without diethylstilbestrol (DES) (2 microM) in the organ bath. 2. Virgin female Wistar rats were injected subcutaneously for 8 days with oestradiol benzoate 150 micrograms kg-1. Control rats received no injections or injection only with the vehicle, ethyl oleate. 3. Detrusor muscle from treated rats showed a decreased sensitivity to acetylcholine (ACh) and carbachol-induced contractile responses. The dose-response curves to these agonists showed a 44% reduction in maximum contractile response for ACh (P < 0.001), and a 38% reduction in maximum contractile response for carbachol (P < 0.05). The addition of 2 microM DES to the bathing medium further significantly reduced the maximum contractile response by 56 and 57% of control respectively. 4. Electrically stimulated detrusor muscle from treated rats showed a significant 49% reduction in the maximum contractile response (P < 0.001). The addition of 2 microM DES to the bathing medium further significantly reduced the maximum contractile response by 66% of control. The tetrodotoxin resistant responses were smaller in pretreated rats, suggesting a reduced sensitivity of the smooth muscle to direct electrical stimulation. 5. The response to 5-HT stimulation by detrusor muscle samples from oestradiol-treated rats showed a non-significant reduction in maximum contractile response, but the addition of 2 microM DES to the bath chamber resulted in a 67% reduction in the response (P < 0.001). 6. Oestradiol pretreatment did not affect the potassium dose-response curve.7. Oestradiol pretreatment reduced the rat detrusor muscle sensitivity to the blocking effect of atropine on the response to electrical field stimulation. Pretreatment also reduced the potentiating effect of physostigmine on the same response.8. These results suggest that oestradiol pretreatment had a modulating effect on cholinergic responses.The addition of oestrogen to the tissue environment enhances this inhibitory effect.

Acetylcholine↗
PubMed1990

Otoplasty: a combined approach.

The described procedures, alone or in combination, provide the flexibility to correct the vast majority of prominent ears. The techniques are easy to learn and very reliable. The deformed scapha, hidden helix, lobule prominence, asymmetry, and recurrent deformity should become historical. An esthetic degree of protrusion and natural appearance of the reconstructed ear can be achieved in almost every case.

Adolescent↗
PubMed1982

The lateral scalp flap for anterior hairline reconstruction.

The lateral scalp flap is a valuable addition to the armamentarium of the trained surgeon who manages the problem of male pattern baldness. With careful patient selection and frank counselling, the quality of reconstruction of the anterior hairline can be enhanced for some patients. The transfer of a large number of hair follicles in their normal pattern of density is an obvious advantage over free graft techniques. The disadvantages of a posterior direction of hair growth in the transposed flap, although readily overcome by careful grooming in most patients, may provide a stimulation for microvascular free flap acceptance in the future. At the present time, the magnitude of the latter procedure and the associated expense preclude consideration of this approach for the usual patient, and it is beyond the capability of many surgeons. Only with accurate reporting of complications and long-term results can one ultimately determine the rightful place of this technique. It is our continuing responsibility to inform patients of the changing options and guide them to a proper treatment based on their individual desire and need. The future generation of physicians and surgeons will undoubtedly dwarf our best effort with their accomplishments. I hope and trust that some day patients with male pattern baldness will no longer require surgery for relief. The ideal hope of the future is discovery of a safe method for prevention or medical treatment.

Adult↗
PubMed1979

Management of the viable soft tissue cover in degloving injuries.

A new method of management of pure degloving injuries has been presented. Return of the distally based flap to its bed without longitudinal tension, use of a temporary biological dressing to protect exposed structures, and early, delayed repair of the residual defect are suggested. The improved survival of the flap and earlier rehabilitation of the patient have been gratifying.

Debridement↗
PubMed1978

Rhinophyma: surgical refinements.

Rhinophyma is classically a benign tumor of unknown etiology and pathogenesis. Once fully developed, it requires surgical treatment; its management has invited controversy for more than a century. We favor electrosurgical sculpturing, removal of the burned tissue by abrasion, treatment of the entire nasal cover as a unit, and the utilization of biological dressings to promote reepithelization. The cosmetic results have been gratifying.

Biological Dressings↗
PubMed1978

Basal cell adenoma of the parotid gland.

Basal cell adenoma of the parotid gland is infrequently seen and rarely documented in the American literature. A case history is presented to emphasize its occurrence in older men and to discuss its pathological appearance. A review of the literature shows that superficial conservative parotidectomy is the treatment of choice because the lesion is considered benign.

Adenoma↗