Helper (CD4+)-to-suppressor (CD8+) T-cell ratios were determined by flow cytometry for 12 patients with early-onset forms of periodontal disease and their appropriate controls. When considered as a group, patients with early-onset periodontal disease showed a markedly depressed CD4+/CD8+ ratio relative to controls (means 0.92 and 1.50 respectively). This difference was significant at the 0.0015% level as determined by the Mann-Whitney test. Separate analysis of patients with either the juvenile or rapidly progressive types of early-onset periodontal disease showed both to have reduced CD4+/CD8+ ratios (means 0.91 and 0.92) relative to their controls (means 1.57 and 1.45) which were both statistically significant (p less than 0.05).

Despite some reports to the contrary, it is generally assumed that early-onset forms of periodontal disease (including both juvenile and rapidly progressive periodontitis) are associated with a defect in neutrophil (PMN) chemotactic behaviour. Using the Boyden chamber technique and N-formyl-methionyl-leucylphenylalanine (FMLP) to assess locomotion by the leading front method, we have failed to show any evidence for such depressed PMN locomotion. Indeed, when PMN chemotaxis and chemokinesis are considered in response to a range of chemoattractant doses our results indicate significant enhancement of all but random locomotion. When taken together with other studies, our results suggest that PMNs from patients with early-onset periodontitis may show abnormal locomotory behaviour which can either be enhanced or reduced in nature. The extent to which these results reflect in vitro methodology in uncertain and, furthermore, their in vivo significance is unclear.

The locomotory behaviour of peripheral blood neutrophils (PMNs) from patients with juvenile (JP) and rapidly progressive (RPP) forms of early-onset periodontal disease was studied using the under agarose technique and n-formyl-methionyl-leucyl-phenylalanine (FMLP) as the chemotractant. PMNs from experimental patients showed normal random, chemotactic and chemokinetic locomotory behaviour when compared with control subjects. Further investigation of single-cell movements using time-lapse video analysis also failed to show any significant differences in locomotory behaviour between the PMNs of experimental and control individuals. We conclude that differences in technique may account for much of the variation which exists in the literature with respect to PMN locomotion in periodontal disease. In the final analysis, it is difficult to dispute direct observation of moving cells, and using this approach, we have been unable to confirm the presence of any PMN locomotory defect in our series of patients with early-onset periodontal disease.

INA PREVIOUS communication (10), while describing the isolation of V-hexane from Pennsylvania petroleum, the abnormal vapor pressure relations of V-hexane and benzene were noted. It was found impossible even after prolonged distillation in very efficient columns to obtain V-hexane containing less than 2.5 per cent by volume of benzene. Other investigators have isolated V-hexane from petroleum [a complete review is given by Bruun and Hicks-Bruun (S, 4) ] but have never obtained it pure unless chemical means were employed to remove the benzene. It has been supposed that V-hexane and benzene form a constant-boiling mixture (12). It is the purpose of the present work to study the binary mixture of V-hexane and benzene, and to determine if V-hexane can be obtained pure from the binary mixture by the addition of a third liquid and by subsequent distillation.Four hundred cc. of the Vhexane-benzene mixture were nitrated, in two separate batches, with a nitration mixture consisting of 58 per cent by weight concentrated sulfuric acid, 25 per cent by weight concentrated nitric acid, and 17 per cent by weight water. Equal volumes of the hydrocarbon and the acid mixture were placed in 500-cc. glass-stoppered bottles which were put on the mechanical shaker for 8 hours. The acid layer was separated, and the hydrocarbon layer washed with concentrated sulfuric acid and then with water.After drying, the hydrocarbon was distilled over sodium in a partial condensing column 12 mm. in diameter, 91 cm. tall, and packed with Lessing rings (5X5 mm.) made of 50-mesh copper screen (11). The distillate after drying over sodium had a boiling point of 67.4°C. (730 mm.) or 68.65°C. (760 mm.), and a refractive index (ro2D°) of 1.3750. The density taken in a Sprengel type pycnometer was 0.6593 (dj°). These physical constants are in close agreement not only with those given above for pure V-hexane, but also with those of synthetic Ar-hexane [boiling point 68.7°C. (760 mm.), refractive index (n\°) 1.3750] prepared in this laboratory.