Resorcinols and catechols: a clinical study of cross-sensitivity

BACKGROUND: All allergic contact dermatitis caused by Philodendron species is common in the Hawaiian islands, and Toxicodendron species are the most common causes of plant-induced allergic contact dermatitis in North America. OBJECTIVE: The purpose of this study was to determine the incidence of cross-sensitivity between these plant species. METHODS: Alkylresorcinols (pentadec[en]yl and heptadec[en]ylresorcinols) were isolated and purified from extracts of Hawaiian-grown Philodendron scandens subspecies scandens and Philodendron lacerum. Alkylcatechols (mixtures of pentadec[en]ylcatechols from an extract of Toxicodendron radicans (poison ivy) were obtained from the Division of Biologics Standards (National Institutes of Health, Bethesda, MD). Seventeen patients from Hawaii and 8 patients from northern California were skin tested with 5 microL (concentrations, 1 to .001 mg/mL) of each allergen applied to the flexor forearm. The test sites remained open and were graded at 72, 96, and 144 hours. All 8 patients from California were naive to Philodendron species, and 8 patients from Hawaii were naive to Toxicodendron species. RESULTS: No cross-reactivity occurred in patients who were Philodendron sensitive and Toxicodendron naive when tested to the homologous Toxicodendron catechols. Conversely, with one exception, no cross-reactivity occurred in patients who were Toxicodendron sensitive and Philodendron naive when tested to homologous Philodendron naive when tested to homologous Philodendron resorcinols. CONCLUSION: Patients who are sensitive to Philodendron species (or other resorcinol-containing plants) may not necessarily be cross-sensitive to Toxicodendron species and vice versa.     

Dynamic Rheological Properties of Mozzarella Cheese During Refrigerated Storage

Storage (G′) and loss (G″) moduli of low-moisture, part-skim Mozzarella cheese were determined at 10 and 20°C during 1 mo of refrigerated aging. At both temperatures, G′ was always greater than G″. Averaged over aging, G′ increased from 90 to 630 and G″ from 44 to 52 kPa at 10°C, and at 20°C G′ increased from 28 to 190 and G″ from 14 to 53 kPa for the frequency range 0.005-20 Hz. Averaged over frequency, both G′ and G″ decreased about 20% at 10°C and 25% at 20°C during aging. Relaxation spectrum, computed from shear relaxation data, was used to calculate the G. The calculated values of G′ were in good agreement with those determined experimentally. These data help predict and compare melting behaviors of such cheeses.     

Crystallization and preliminary X-ray analysis of restriction endonuclease FokI bound to DNA

8 patients with paludism diagnosis due to Plasmodium vivax and deficiency of glucose-6-phosphate dehydrogenase that should receive antipaludism radical treatment with primaquine were studied. It was determined that 87.5% of the patients presented hemolysis but its relation with the enzymatic activity was not significant (p > 0.05). 50% of the patients could not finish their treatment because of the appearance of important hemolysis. It is concluded that primaquine should not be used indiscriminately among those patients with deficit of glucose 6 phosphate dehydrogenase.     

Abnormal cholesterol biosynthesis in the Smith-Lemli-Opitz syndrome

The Smith-Lemli-Opitz syndrome is caused by an inherited defect in 7-dehydrocholesterol-delta7-reductase, the enzyme that catalyzes the last reaction in cholesterol biosynthesis, the conversion of 7-dehydrocholesterol to cholesterol. As a result, deficient cholesterol is produced and the precursor 7-dehydrocholesterol and derivatives (8-dehydrocholesterol and 19-nor-5,7,9(10)-cholestatrien-3 beta-ol) accumulate. Tissues (especially brain) deprived of cholesterol, or because of the deposited sterol precursors and derivatives, develop abnormally and function poorly. Replacement with dietary cholesterol may help correct the biochemical defects and improve symptoms.