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Biomedical subjects

H J Dodd

Publications and source records attributed to H J Dodd.

At least 19 recordsLinked to original sources

Venous leg ulcers and arthropathy.

Reduced ankle mobility impairs the venous muscle pump and this leads to an increase in mean venous pressure in the lower leg. We have previously shown that pressure-induced venous distension leads to cutaneous hypoxia which is caused by arteriolar vasoconstriction in response to a spinal reflex. The prolonged cutaneous hypoxia which is thus a consequence of sustained elevation of venous pressure is an important factor in the development of gravitational ulcers. It is postulated that the increased incidence of leg ulcers in patients with rheumatoid arthritis is the result of impairment of the efficiency of the venous muscle pump by reduced ankle mobility. Conversely, the elevation of venous blood pressure in patients with venous insufficiency may lead to arthropathy in the ankle. The hypothesis is presented that prolonged elevation of venous blood pressure causes injury to both the ankle joint and veins leading to chronic reciprocal damage to both. This explains the frequent association between arthropathy of the ankle and venous leg ulcers.

Ankle Joint

The short-term benefit and long-term failure of ultraviolet light in the treatment of venous leg ulcers.

Ultraviolet light has in the past been advocated for the treatment of venous leg ulcers on the assumption that it increases skin blood flow and reduces skin hypoxia. Our results show that UV light increases skin-oxygen tension of the lower leg and inhibits the normal vasoconstrictor response on standing. However, this effect is short lived and is followed after 2 days by a return of the vasoconstrictor reflex and a marked decrease in skin oxygenation which continues for at least 2 weeks. Since UV irradiation improves skin oxygenation for only 48 h, it cannot be recommended as a form of treatment for venous leg ulcers.

Adult

Surgical correction of venous incompetence restores normal skin blood flow and abolishes skin hypoxia during exercise.

Posture has long been recognized to be a crucial factor in the etiology of venous leg ulcers. Activation of the stretch receptors in the veins by venous distention induces reflex vasoconstriction and hypoxia. In patients with defective venous return, exercise fails to reduce venous pressure when the legs are dependent; therefore, hypoxia persists during exercise. Surgical treatment of venous incompetence abolishes the abnormal venous reflux and restores the normal vasodilator response to exercise, thereby correcting the sustained hypoxia observed in patients with venous leg ulcers.

Bandages

Seborrheic dermatitis and malignancy. An investigation of the skin flora.

The skin flora of patients with disseminated malignant disease and seborrheic dermatitis has been investigated and compared with controls as well as with otherwise healthy patients suffering from seborrheic dermatitis. Although significant differences were detected in both bacterial and yeast counts between different sites on the body, no significant qualitative or quantitative differences were found between the three groups of subjects. Whereas abnormalities of the skin flora have been described in seriously ill patients and in individuals subjected to occlusion, we were unable to demonstrate any changes in skin flora in patients with malignant disease and seborrheic dermatitis. Our results do not support the view that increased numbers of Pityrosporum yeasts are important in the pathogenesis of seborrheic dermatitis.

Bacteria, Aerobic

Cutaneous malignant histiocytosis--a clinicopathological review of five cases.

Malignant histiocytosis is a rare, and usually fatal, tumour which may involve the skin. The clinical and pathological changes are described in five patients who presented with skin nodules as the initial feature. We witnessed spontaneous healing of lesions, a previously described phenomenon which may cause diagnostic confusion. It is suggested that patients presenting with malignant histiocytosis confined to the skin form a sub-group with a more favourable prognosis.

Adult

Oral acyclovir in the suppression of recurrent non-genital herpes simplex virus infection.

In a double-blind, placebo-controlled, cross-over trial in 11 patients suffering eight or more episodes of recurrent non-genital herpes simplex virus (HSV) infection per annum, only two patients experienced a recurrence during treatment with oral acyclovir (200 mg 4 times daily) for up to 12 weeks, compared with nine during placebo treatment (P = 0.016). Although lesion development was effectively suppressed in nine of the patients whilst taking acyclovir, the development of prodromal symptoms, and occasionally erythema, was reported by five. There was no difference between acyclovir and placebo in the time to the next recurrence following completion of treatment. No patient reported any side effects of either placebo or acyclovir therapy. It is believed that this is the first report of any form of oral therapy which is effective in suppressing recurrent non-genital HSV infection in immunocompetent patients.

Acyclovir