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Biomedical subjects

T M Macleod

Publications and source records attributed to T M Macleod.

15 recordsLinked to original sources
PubMed1989

Reversed-phase high-performance liquid chromatographic method for the quantification of 5-hydroxymethylfurfural as the major degradation product of glucose in infusion fluids.

Analysis of 5-hydroxymethylfurfural (5-HMF) is an important indicator of degradation in glucose infusion fluids. Current pharmacopoeial methods for analysis are insensitive and non-specific. A method is described here, incorporating an internal standard, to give a sensitive, accurate and precise method, suitable for use in the quality control of glucose infusion fluids, and with possible applications for the quantitative determination of 5-HMF in food and drink, bacterial cultures and hydrothermolysed wood.

Chromatography, High Pressure Liquid↗
PubMed1989

A study of the photodegradation of leukotriene B4 by ultraviolet irradiation (UVB, UVA).

In view of the presence of the polymorphonuclear leukocyte (PMN) chemoattractant Leukotriene B4 (LTB4) in the surface scale of the psoriatic lesion and the known therapeutic effect of phototherapy in psoriasis, the photostability of LTB4 was investigated. LTB4 was irradiated with dosages of UVB (290-320 nm) ranging from 100-1500 mJ cm-2 and with dosages of UVA (320-400 nm) ranging from 5-40 J cm-2. Topical application of UVB irradiated LTB4 to the forearm skin of normal volunteers showed a marked reduction in cutaneous erythema, paralleled histologically by reduced transepidermal PMN migration when compared with sites of application of unirradiated and UVA irradiated LTB4. High performance liquid chromatography (HPLC) demonstrated a dose-dependent photodegradation of LTB4 by UVB irradiation. UVA irradiation produced no such effect. The wavelengths responsible lie within the absorption spectrum of LTB4. In vitro chemotaxis studies, using an under agarose technique, showed a statistically significant reduction in the migration of PMN from both psoriatic and non-psoriatic subjects to the UVB irradiated LTB4 compared with the unirradiated LTB4, whilst UVA irradiated LTB4 produced a normal PMN chemotactic response.

Chemotaxis, Leukocyte↗
PubMed1984

Dapsone and human polymorphonuclear leucocyte chemotaxis in dermatitis herpetiformis.

Polymorphonuclear leucocyte chemotaxis was investigated in 6 patients with active dermatitis herpetiformis in the untreated state and when under control with Dapsone. Control studies were undertaken in 7 healthy volunteers. No significant difference in chemotaxis was demonstrated between the active, treated and control groups. Furthermore, when Dapsone in physiological concentrations was added separately in all three groups there was no additional effect on chemotaxis. These results clearly show that polymorphonuclear leucocytes from active untreated dermatitis herpetiformis have normal chemotactic activity compared with those from the same patients in the treated state and controls. Additional Dapsone did not alter these findings.

Adult↗
PubMed1976

The leukocyte migration inhibition test in allergic nickel contact dermatitis.

No statistical difference was found between the migration indices of nickel sensitive and control subjects using the leukocyte migration inhibition test with two concentrations of nickel sulphate. The results contrast with the specific positive results demonstrated previously in the same subjects with the lymphocyte transformation test.

Cell Migration Inhibition↗
PubMed1975

A study of physical light screening agents.

In those photodermatoses in which the action spectrum involves wavelengths outside the short ultraviolet (i.e. is greater than 320 nm) little protection can be obtained against long UV (is greater than 320 nm) by the application of chemical light screening agents. An action spectrum involving wavelengths is greater than 320 nm is a common occurrence and may necessitate the additional provision of protection from a physical light screening agent. Such a physical agent is titanium dioxide and in a study of its use in a variety of formulations using in vitro techniques it was shown to be effective throughout the wavelengths 400-700 nm. It was also shown to have a satisfactory protective capacity in those photodermatoses in which the action spectrum involves wavelength peaks 365 nm (335-395 nm) and 400 nm (370-430 nm). It also has a reasonable cosmetic acceptability provided care is taken to incorporate in the formulations colouring agents which can be varied to suit the individual patient.

Cosmetics↗
PubMed1975

A study of chemical light screening agents.

In a group of 104 non-photosensitive subjects and seventy-eight suffering from a variety of photodermatoses, the most effective protective preparation against irradiation by short UV sunburn wavelengths (smaller than 320 nm) was found to be a mixture of 5% para-aminobenzoic acid and 2.5% of the ester amyl dimethylaminobenzoate in 70% ethanol with para-aminobenzoic acid being usually more effective than the ester, and mexenone the least effective individually. The protective capacity was found to be reduced by showering but not by exercise. The addition of glycerol to the formulations did not affect their protective capacity although the addition of propylene glycol did increase the protection obtained.

Aminobenzoates↗