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Biomedical subjects

H Maibach

Publications and source records attributed to H Maibach.

At least 73 records · Page 4Linked to original sources
PubMed1984

Patch test allergens in petrolatum: a reappraisal.

Patch test materials in petrolatum, from 3 different manufacturers and 14 different types were evaluated by gross and microscopic examination. The allergens were noted to be suspended as particles or droplets in the vehicle. Obvious variations in both size and structure of the included allergen were found with the same chemicals but of different manufacture. Several materials do not meet the pharmaceutical standards which should be requested regarding stability, particle size and packing. A more detailed declaration is proposed.

Allergens↗
PubMed1984

Amount of nickel applied with a standard patch test.

The concentration of nickel sulphate was determined in 9-16 mg test samples from commercially available patch test antigens. With two different manufacturers of 2.5% nickel sulphate in pet, the concentration range of 25 samples was 0.7 and 1.1% (+/- 2 SD) respectively, and with one manufacturer of 5.0% nickel sulphate in pet, the range was +/- 0.5%. In a normal patch test, the volume of patch test material applied with the Finn chamber technique should be 12-18 microliter (9-16 mg), but has been found to range between 9 and 50 microliter. Thus the amount of nickel applied in standard patch tests varies within at least 6-fold limits.

Dermatitis, Contact↗
PubMed1983

Malathion binding to sections of human skin: skin capacity and isotherm determinations.

Human autopsy skin was sliced into three sections: an outer epidermis-rich layer, a middle dermis layer, and an inner dermis and subcutaneous fat layer. Each skin slice was bathed in malathion solutions over a 100-fold concentration range of 0.02-3.0 microM/g skin for 48 h at 37 degrees C. Malathion uptake approximated 50% for each skin layer over the total concentration range. Skin capacity for malathion is thus large. Single and double compartment dialysis was used to determine free and bound malathion. Isotherm calculations gave a partition coefficient intercept for epidermis-rich and dermis tissues with aqueous buffer of 2.72 and 2.74, respectively. That of the inner layer of skin was less at 1.70. When malathion was dialyzed against simulated plasma, the binding decreased 2-fold. Since the least partition coefficient (less bound malathion) was in the inner layer of skin, and since malathion has a preference for plasma over water, the two (inner skin and plasma) may combine to create the sink conditions necessary for malathion percutaneous absorption into the body.

Binding Sites↗
PubMed1983

Relationship between chemical structure and allergenicity: aromatic amines.

This review utilizes current clinical and experimental contact sensitization data with aromatic amines to hypothesize on the relationship between chemical structure and allergenicity. The available data suggests: 1. A Primary amino group in the ring induces sensitizing properties; 2. aromatic amine allergenicity is related to basicity, resulting from the action of substituents in the ring; 3. electron donor substituents enhance whereas electron acceptor substituents attenuate the activity.

Allergens↗
PubMed1982

Removable fluid-containing chamber for in vivo guinea pig skin studies.

A removable, fluid-tight chamber is discussed that may be used to measure ion flux through the skin. This chamber adheres to clipped guinea pig skin with the use of silicone rubber adhesive, where hair stubble facilitates attachment. The technique also should work well for other hairy species. Experiments may be performed on hairless skin provided the adhesive is incompletely cured and the chamber is held in place by a strap.

Animals↗
PubMed1981

Transepidermal chloride flux through hydrated skin: combination chloride electrode.

A combination chloride electrode was used to determine quantitatively the outward rate of epidermal chloride transport in vivo. Regional anatomical variation and the effects of topical agents and cellophane tape strippings on the rate of chloride diffusion were determined. Transepidermal chloride flux through hydrated skin appears to be an alternative method for determining stratum corneum function in vivo.

Acetates↗
PubMed1981

Immediate and delayed onset "skip area" dermatitis presumed secondary to topical phenol exposure.

A 21-year-old man was in brief accidental skin contact with epoxy resin stripper containing 10% phenol. He developed a painful, superficial necrotic eruption which slowly extended proximally without any further contact with the chemical, leaving skip areas of normal skin. About 3 and 7 months later he reported spontaneous flares within the area of original contact. Gradual release from an initially formed phenol-protein complex is thought to be responsible for the progression beyond the contact area and the delayed reaction.

Administration, Topical↗
PubMed1981

The effect of short-term occlusion on the cutaneous flora in atopic dermatitis and psoriasis.

The effect of occlusion on the cutaneous microbial flora in patients with atopic dermatitis and psoriasis was measured. Significant increases in the density of Staphylococcus aureus and lipophilic diphtheroids were noted after occlusion in eczematous and psoriatic skins. While the incidence of S. aureus increased in psoriatic skin after occlusion, this trend was not noted in dermatitic skin.

Bacteria↗
PubMed1981

A clinical screening program for topical chemotherapeutic drugs in psoriasis.

In this national, multicenter cooperative study, a standardized drug screening program was designed and evaluated to test the clinical effectiveness of 30 topically applied chemotherapeutic drugs to psoriasis. Appropriate concentrations and vehicles for topical administration were selected with regard to clinical testing consisted of a double-blind application of test agents to psoriatic plaques under occlusion daily for up to nine days. Drugs known to be topically active in psoriasis, eg, thiotepa, fluorouracil, and betamethasone valerate, were easily detected in the clinical protocol, confirming the validity of this topical drug screening program. Seven drugs produced substantial clinical improvement with evidence of clearing; nine drugs produced slight improvement; 14 drugs had no effect. No systemic toxid reactions occurred. This screen should be useful to test other potential antipsoriatic drugs and to evaluate potential animal model screens for their predictive values with the same drugs.

Adult↗
PubMed1980

In vivo transepidermal water loss and epidermal occlusive hydration in newborn infants: anatomical region variation.

Transepidermal water loss (TEWL) was measured from the abdomen, buttock, and central forearm in 13 term infants by employing an electrolytic water analyzer (Meeco). The hydration level (HL) at these sites following one hour of occlusion and the resulting post-occlusion TEWL were measured. No apparent difference in TEWL was found between regional sites. The forearm and buttock HL appeared similar, while the abdomen values tended to differ considerably from both. Post-occlusion TEWL appeared significantly higher than normal TEWL. Since the buttock and forearm TEWL reflected similarly structured stratum corneum, future studies on the more accessible forarm may be extended by application to the buttock.

Abdomen↗
PubMed1980

Allergenicity of aminobenzene compounds: structure-function relationships.

Six aminobenzene compounds (p-phenylenediamine, p-aminophenol, p-toluidine, p-sulfanilic acid, p-aminobenzoic acid, and p-nitroaniline) were used to correlate chemical structure and allergenicity. To obtain more quantitative data, the challenges were made at several concentrations. Utilizing for sensitization four 24 h occlusive patches in guinea pigs, we observed that compounds with activating chemical groups (-NH2, -CH3, -OH) were more potent sensitizers than compounds with deactivating groups (SO3H, COOH, NO2). This information should assist predictive identification of hair dyes, local anaesthetics and other aminobenzene structures that are more or less allergenic.

Allergens↗
PubMed1979

Cell surface lipid in the amniotic fluid.

Limitations of cell staining and light microscopy have led to confusion as to the etiology and morphologic characteristics of nile-blue-sulfate-stained orange cells in amniotic fluid. Nomarski Differential Interference Contrast Microscopy (NDICM) was used to study these cells as they appear in their unstained state. The presence of lipid-bearing cells was correlated with gestational age and mode of delivery, and incubation studies were applied toward an evaluation of the mechanism of lipid formation. Lipid-bearing cells in the amniotic fluid appeared after 37 1/2 weeks' gestation in association with fetal lung maturity.

Amniotic Fluid↗
PubMed1978

Glyceryl p-aminobenzoate patch testing in benzocaine-sensitive subjects.

Benzocaine-reactive patients were patch tested to two commercial sources of glyceryl p-aminobenzoate containing varying concentrations of benzocaine as a contaminant. Eleven of 20 reacted to the source with approximately 0.3% benzocaine; none reacted to the source with approximately 0.001% benzocaine.

4-Aminobenzoic Acid↗