Laboratory diagnosis and interpretation of tests for syphilis.

The lack of a method for demonstrating the presence of Treponema pallidum by growth necessitates the use of alternative methods. Traditionally, these methods are divided into direct detection methods (animal inoculation, dark-field microscopy, etc.) and serologic tests for the presence of patient antibody against T. pallidum. Serologic methods are further divided into two classes. One class, the nontreponemal tests, detects antibodies to lipoidal antigens present in either the host or T. pallidum; examples are the Venereal Disease Research Laboratory and rapid plasma reagin and tests. Reactivity in these tests generally indicates host tissue damage that may not be specific for syphilis. Because these tests are easy and inexpensive to perform, they are commonly used for screening, and with proper clinical signs they are suggestive of syphilis. The other class of test, the treponemal tests, uses specific treponemal antigens. Confirmation of infection requires a reactive treponemal test. Examples of the treponemal tests are the microhemagglutination assay for antibodies to T. pallidum and the fluorescent treponemal antibody absorption test. These tests are more expensive and complicated to perform than the nontreponemal tests. On the horizon are a number of direct antigen, enzyme-linked immunosorbent assay, and PCR techniques. Several of these techniques have shown promise in clinical trials for the diagnosis of congenital syphilis and neurosyphilis that are presently difficult to diagnose.

Evaluation of antibacterial sensitivity testing methods for methicillin-resistant Staphylococcus aureus in a dermatology outpatient population.

Over a period of one year, 1986-1987, 116 strains of Staphylococcus aureus were isolated from patients attending two outpatient dermatology clinics in Houston, Texas. The purpose of this study was to evaluate the adequacy of routine antibiotic sensitivity testing methods for detecting methicillin-resistant Staphylococcus aureus (MRSA). The Kirby-Bauer disk diffusion method was compared with a commercially available screening medium containing 6 micrograms/ml of oxacillin and 4% NaCl. The minimal inhibitory concentration (MIC) of methicillin, oxacillin, and oxacillin with 4% NaCl to S aureus using the agar dilution method was also determined. Approximately 90% of S aureus strains produced beta-lactamase and were resistant to penicillin and ampicillin. By disk diffusion, no strains were resistant to methicillin, though diameters of zones of inhibition were between 10 and 14 mm in seven strains. All strains proved to be sensitive to methicillin by MIC determinations and on the oxacillin-NaCl screening medium. The MIC of methicillin was 2.5 micrograms/ml for the majority of strains of S aureus, between 0.16 and 0.31 microgram/ml for oxacillin, and 0.08 to 0.16 microgram for oxacillin with 4% NaCl. We concluded that the incidence of MRSA in an outpatient dermatology population is low, and a combination of disk diffusion and oxacillin-NaCl screening is adequate for testing sensitivity.

Familial dystrophic periodic shedding of the nails.

A patient with an autosomal dominant nail dystrophy characterized by periodic, asymptomatic shedding of the nails followed by regrowth is described herein. This highly penetrant disorder is similar to two earlier cases found in the dermatologic literature.

Milia en plaque.

Two patients with an unusual cutaneous lesion consisting of milia on an erythematous edematous base are presented; the clinical and histologic features are described. The name "milia en plaque" is proposed for this unusual condition.

Systemic protection by antioxidants against UVL-induced erythema.

An antioxidant supplemented diet provided marked systemic protection against ultraviolet light mediated erythema in hairless mice. Among the individual constituents of the diet, butylated hydroxytoluene was most effective whereas glutathione and vitamins C and E afforded negligible protection. The mixture of antioxidants, and butylated hydroxytoluene individually, demonstrated diminished, but significant, protection when applied topically. The safety of this systemic photoprotectant and its clinical relevance at present is unknown.

Influence of wind on chronic ultraviolet light-induced carcinogenesis.

Wind enhances the carcinogenic effect of chronic Iltraviolet radiation (UVL). This was demonstrated in hairless mice that were irradiated for 42 weeks with mercury are lamps. One group of animals was exposed to continuous wind flow of 2.7 m/s except for the daily I-2 min time interval when they were removed from the wind tunnel and irradiated. Another group of animals received identical irradiation but were protected from wind. The first tumour appeared in the UVL and wind group after 105 days of irradiation, and at 164 days of irradiation all surviving mice in the group had developed tumours. The group of mice receiving identical irradiation but protected from wind had their first tumour appear at 154 days of irradiation, and by 164 days of irradiation only 40% of the mice had developed tumours.

Nuclear and nucleolar ultrastructure of Sézary cells.

Sézary cells were studied in the peripheral blood and characteristic skin lesions of the Sézary syndrome and mycosis fungoides by transmission electron microscopy to obtain more information on their nuclear and nucleolar ultrastructure. Sézary cells contain nucleoli with nucleolonemas or ring-shaped nucleoli similar to those of lymphoblasts and mature lymphocytes. "Maturation asynchrony" of the nucleolus and cytoplasm was evident in some cells that contain large numbers of ribosomes and ring-shaped nucleoli and in other cells that contain nucleoi with nucleolonemas and few ribosomes. The maturation asynchrony of the nucleolus and the cytoplasm, the presence of mitochondrion-like inclusion bodies in the nucleus, and fusion of mitochondria with the nucleus in Sézary cells are ultrastructural abnormalities of this neoplastic lymphocytic variant. The presence of the intranuclear "mitochondrion-like" inclusion body and nuclear rodlets in Sézary cells were exceptional findings.

Physiological changes in hairless mice maintained on an antioxidant supplemented diet.

Several physiological parameters were measured in hairless mice maintained on a diet supplemented with antioxidants. Comparisons to animals on control diet revealed higher water-soluble antioxidant content of skin and increased liver weight. Only small differences in body weight occurred and no distinct histological changes were observed in skin or liver.

Inflammatory metastic carcinoma. Carcinoma erysipelatoides.

A patient with pulmonary adenocarcinoma had an erythematous inflammatory lesion resembling erysipelas on the chest wall. Results of a skin biopsy disclosed groups of metastatic adenocarcinoma cells in the dermis, subcutaneous tissue, and lumina of the lymphatic vessels. The diagnosis of the inflammatory metastatic carcinoma should be considered in any persistent and therapeutically unresponsive skin eruption that resembles an infectious process. Careful attention to the clinical features, lack of febrile response, and absence of leukocytosis should assist in making the correct diagnosis of a noninfectious process.

Serologic diagnosis of syphilis: an update.

Tests used in the serologic diagnosis of syphilis can be divided into two main groups: nontreponemal (reagin) tests and treponemal tests. The most widely used nontreponemal test is the Venereal Disease Research Laboratory (VDRL) slide test, and the standard treponemal test is the manual fluorescent treponemal antibody-absorption (FTA-ABS) test. These tests and other newer tests available for the serologic diagnosis of syphilis are reviewed, with emphasis placed on their current clinical usefulness.

The microhemagglutination assay for Treponema pallidum antibodies (MHA-TP), a new treponemal test for syphilis: where does it fit?

The status of a new treponemal test, the Microhemagglutination Assay for Treponema pallidum Antibodies (MHA-TP) is reviewed and compared with regard to its sensitivity, specificity, and current clinical application to the VDRL slide test, the most widely used non-treponemal test, and to the manual FTA-ABS test, the standard treponemal test. At present, the MHA-TP test seems to combine the simplicity and lower cost of nontreponemal tests and the sensitivity and specificity of treponemal tests, and thus enjoys features of both a screening and verification procedure. However, additional clinical experience with the test is needed before its role in the serologic diagnosis of syphilis can be conclusively determined.