Improved rapid photometric assay for quantitative measurement of PMN migration.

We developed an improved quantitative method to measure in vitro polymorphonuclear leukocyte (PMN) migration using an assembly consisting of a 96-well chamber, polycarbonate filter membrane, and a 96-well microtiter plate. The convenience in setup and counting of migrated cells using this method allows processing of 80 samples and 16 controls in a short assay time of only 2 h. The peroxidase contained in PMNs was used as a marker enzyme to determine the number of migrated cells.

Transfer of conjugal elements in oral black-pigmented Bacteroides (Prevotella) spp. involves DNA rearrangements.

Conjugal genetic elements in isolates of oral black-pigmented Bacteroides denticola (Prevotella denticola) and B. intermedius (P. intermedia) transfer tetracycline and penicillin resistance in the absence of plasmids.

Elimination of oblique flow artifacts in magnetic resonance imaging.

We present an analysis of how flow oblique to the frequency-encoding direction generates displacement artifacts in MR imaging and show that for flow which has constant velocity between the start of the phase encoding and the center of the echo it is possible to eliminate these artifacts by gradient moment nulling in the phase-encoding direction. However, unlike the standard moment nulling calculations for flow compensating the frequency-encode and slice-selection gradients, the phase-encoding first moment must be nulled specifically with respect to the echo center. Limitations of this method imposed by finite gradient strengths are analyzed.

Absence of tumorigenicity in athymic mice by normal human epidermal keratinocytes after culture in serum-free medium.

The very rapid growth rate (1 population doubling/day) of normal human epidermal keratinocytes (HK) cultured in serum-free medium can be utilized for wound closure in burn treatment. However, rapid growth in vitro may present the possibility of neoplastic transformation. To investigate this possibility, HK were cultured from primary isolation to large populations in MCDB 153 medium supplemented with epidermal growth factor (EGF, 10 ng/ml), insulin (5 micrograms/ml), hydrocortisone (0.

Chitin synthase in encysting Entamoeba invadens.

Although the cyst wall of Entamoeba invadens contains chitin, synthesis of this structural polymer during encystation has not been described before. Here we report that conditions which stimulate encystation of the parasite lead to increased chitin synthase (ChS) activity, measured by incorporation of [3H]GlcNAc ([3H]N-acetylglucosamine) from UDP-GlcNAc. The radiolabelled product was precipitable by trichloroacetic acid or ethanol and identified as chitin because it was digested by purified chitinase to radioactive chitobiose and GlcNAc.

The impact of concomitant viral pathogens on the course of Pneumocystis carinii pneumonia.

A large retrospective study was conducted to evaluate the impact of culturing cytomegalovirus from the respiratory secretions of AIDS patients with Pneumocystis carinii pneumonia. Pneumocystis carinii was found in 220 (67%) of 327 episodes and cytomegalovirus was found in 106 (48%) of the P. carinii-positive patients.

Catheterization of branchial sinus tracts. A new method.

The complete surgical extirpation of branchial cleft abnormalities is essential in avoiding recurrent disease. The most technically difficult maneuver is often the localization and excision of associated sinus tracts and fistulae. The authors communicate a simple yet effective technique for dealing with this difficulty utilizing the Fogarty embolectomy catheter.

Isolation and expression of the gene for a major surface protein of Giardia lamblia.

To study the interactions between the parasitic protozoan Giardia lamblia and its environment, we have cloned the gene that encodes the two major surface-labeled trophozoite protein species. Sequence analysis of this gene reveals a single open reading frame specifying a hydrophilic, cysteine-rich (11.8%) protein of 72.

Immunologic consequences of exogenous surfactant administration.

In conclusion, we have shown that human surfactant is immunogenic and that circulating surfactant-antisurfactant immune complexes are detectable in the plasma from infants and in adults with RDS. We found these immune complexes regardless of whether exogenous surfactant was used in the individual treatment regimen. These immune complexes do not yet seem to cause disease in the short term.

Small-intestinal factors promote encystation of Giardia lamblia in vitro.

Bile salts and fatty acids stimulated differentiation of cultured Giardia lamblia trophozoites into water-resistant cysts at the slightly alkaline pH of the small intestinal lumen. Maximum encystation occurred at pH 7.8.