A viewpoint on the coming impact of emerging diseases.

Infectious disease is now the third leading cause of death in the United States, and the No. 1 cause in the Third World. These diseases are the most important public health crisis facing the health care community. As part of that community, dentists must be armed with the knowledge necessary to take their part in the war against these infectious agents.

Dental operatory water lines.

Water samples were collected from dental handpiece and air-water syringe lines at various times during the day and cultured for the presence and prevalence of various microbes. It was found that the longer a dental unit was out of use, the greater the microbial build-up in water lines. However, purging lines for two to three minutes at the start of the day and between patients significantly reduced microbial presence.

Inhibition of sperm motility by bovine serum components.

Various sources and components of mammalian sera were evaluated for their ability to maintain or inhibit sperm motility. Human, rabbit, hamster, and porcine sera were equal in ability to maintain motility of human sperm. Four sources of fetal calf serum and one source of neonatal calf serum were unable to maintain motility of human sperm or sperm-fertilizing potential. In the presence of human serum, fetal calf serum actually inhibited human sperm motility. Fetuin, a component of fetal calf serum, contained the inhibitory activity. An inhibitory effect of fetuin on porcine and caprine sperm motility was also observed. The inhibitory activity resided in the second peak when fetuin was separated by isoelectric focusing. The sperm head membranes remained impermeable to dye, and mitochondrial membrane potential was maintained after motility had been reduced to almost zero by incubation with fetuin and fetuin fractions. Fetuin or the active portion of the molecule may be a useful component of a vaginal contraceptive and in research where inhibition of motility is desirable.

Stannous fluoride and its effects on oral microbial adhesive properties in vitro.

The effect of sodium and stannous fluoride compounds on the coherence of Streptococcus mutans was examined. Both commercial and reagent grade preparations were tested on S. mutans, strain 6715. Test fluoride aliquots at various concentrations were added to sucrose suspensions of S. mutans at a starting microbial suspensions equivalent to 25% transmission as read in a spectrophotometer. Test samples were rotated at 35 degrees, 80 rpm in an incubated orbital shaker. Analysis at 560 nm at various time periods, was performed to determine increases in %T as a function of aggregate formation. SnF2 preparations routinely inhibited coherence at concentrations as low as .001%, whereas NaF showed no effects on microbial cell-to-cell coherence.

Monolayer and suspension culture of human prolactin-secreting pituitary adenoma.

In order to study the hormonal characteristics of human prolactin-secreting pituitary adenomas, in vitro monolayer and suspension cultures from human pituitary glands were established. Optimal conditions for cultures included enzymatic dispersion into viable single-cell suspensions with the use of 1% collagenase in phosphate-buffered saline solution. After pelleting the dispersed cells by centrifugation (800 rpm for 10 minutes), they were cultured in RPMI medium that contained 20% fetal calf serum and then incubated at 37degrees C in 5% CO2. Cells were subcultured weekly at a ratio of one plate to two. In an attempt to establish whether bromocriptine has a direct inhibitory effect on pituitary secretion of prolactin (PRL), variable doses of bromocriptine were added to duplicate plates. The addition of bromocriptine to the culture medium induced suppression of PRL within 7 days. In conclusion, this study demonstrated that either monolayer of suspension cultures of human PRL secreting adenomas can be established, and that bromocriptine in doses of 1 ng/plate or more has a direct inhibitory effect on the secretion of PRL.

A fetuin-like antigen from human nephroblastoma.

An antigen was detected in pooled human nephroblastomas using antiserum prepared in rabbits against an ethylemediaminetetra acetic acid (EDTA) extract of the tumors. This antigen was not found in normal human plasma or kidney extracts, and was not related to the ABO or Forssman blood groups. The antigen was detected in extracts of cultured nephroblastoma cells, but was not present in extracts of normal human fetal kidney cell cultures. The antigen is believed to be present at the cell surface, as cell viability was not significantly lowered during the extraction procedure. A reaction of complete identity was demonstrated by Ouchterlony double diffusion experiments with this antigen and purified bovine fetuin. The antigen was not found in extracts of human fetal spleen, thymus or kidney, nor in human fetal serum. Furthermore, the antigen does not possess determinants in common with the human alpha-fetoprotein of hepatomas, nor was it detected in human renal clear cell carcinoma. Initial characterization of the antigen showed it to be nondialysable, not sedimentable at 100,000 times g for 2 h, stable to repeated freeze-thawing and to incubation at 56 degrees C for 1 h, and water soluble over a wide pH range. The antigen was susceptible to digestion with pronase and trypsin and possibly hyaluronidase, but not to ribonuclease or neuraminidase. The protein portion is therefore of major importance to the structural integrity of this antigen. The relationship between this antigen and other abnormal materials reported previously in nephroblastoma patients is being studied.

Isolation of Wilms' tumor antigens by chelation.

A procedure for ethylenediaminetetraacetate extraction of minced Wilm's tumor was assessed as a method for isolating Wilm's tumor antigens. An antigen was detected by immunodiffusion using an adsorbed antiserum to this extract. This antigen was also found in ethylenediaminetetraacetate extracts of in vitro cultures of nephroblastoma cells.

Cell proliferation: enhancement by extracts from cell surfaces of polyoma-virus-transformed cells.

Dispersion of confluent monolayers of BHK21 cells with ethylenediaminetetraacetate yields a material that inhibits cell proliferation, whereas identical extraction of polyoma-virus-transformed cells provides material which enhances cellular proliferation. The material was partially characterized.