[Mercury concentrations in blood and urine before and after placement of non-gamma 2 amalgam fillings]. / Quecksilberkonzentration in Blut und Urin vor und nach dem Legen von Non-gamma 2-Amalgamfüllungen.

The object of the study was to determine whether mercury concentrations in blood and urine were increased directly after placement of non-gamma 2-amalgam fillings. Our cohort consisted of 45 subjects, male and female, age between 19 and 45 years, who had amalgam fillings and were not exposed to mercury on their jobs. Thirty subjects received non-gamma 2-amalgam fillings, 15 did get new fillings. Cold, flameless atom absorption spectrometry was used to analyze mercury levels in blood and urine samples before and for 24 hours after placement of the amalgam fillings at one hour intervals. Mercury concentrations in blood (before and after) and - before placement of new non-gamma 2-amalgam fillings - in urin were below the normal upper limit in all 45 subjects. Mercury concentrations in urin after placement of new fillings did not show any increase over 24 hours. Median values varied between 1.0 and 2.1 micrograms Hg/g creatinine and thus were also within the normal range.

Lactate influx and efflux in the 'Streptococcus mutants group' and Streptococcus sanguis.

Lactate influx was measured in Streptococcus sanguis and in several strains of Streptococcus mutans by comparing the intra- and extracellular distribution of (14C)-lactate. Lactate efflux was followed enzymatically against rising external lactate concentration. The glucose concentration was monitored in the same way. With S. sanguis OMZ 9, lactate was transported into the cells when a high external lactate concentration and a pH gradient were established. The transport rate was approximately 1,000 nmol lactate per minute and milligram protein. No lactate influx could be measured with four strains of the 'S. mutans group' (OMZ 51, 634, T3/13 and NCTC 10449). Metabolizing cells of S. mutans NCTC 10449 were able to transport lactate even against an external lactate concentration of 92 mmol/l at pH = 7. The transport rates ranged from 1,200 to 750 nmol lactate/min mg protein decreasing with increasing external lactate concentration. While an external pH = 9 had little influence on transport, transport rates decreased to 440 nmol/min mg protein at pH = 5.

The acid pattern in human dental plaque.

Lactic and volatile acids in standardized plaque samples from 11 subjects have been estimated by means of HPLC before and after exposure to sucrose in vivo. Total acid differed considerably between subjects, but the ratio of acids estimated within the plaque from different persons did not vary significantly. The time-dependent acid pattern following sucrose rinsing allowed the plaque samples to be divided into two groups: one showing only small changes in total acid production; and the other exhibiting a distinct increase in total acid up to 15 min after sucrose rinsing.