Effects of subtherapeutic concentrations of chlorhexidine gluconate on germ tube formation of oral Candida

OBJECTIVE

The main objective of this study was to investigate the effect of brief exposure to subtherapeutic concentrations of chlorhexidine gluconate on germ tube formation of Candida albicans isolates obtained from smokers, diabetics, asthmatics using steroid inhalers and healthy individuals.

MATERIALS AND METHODS

Forty isolates of C. albicans were used in this study. All these isolates were quantified for germ tube formation without exposure to the drug and were used as the control group for data analysis. Isolates were also exposed to three subtherapeutic concentrations of chlorhexidine gluconate (0.00125, 0.0025 and 0.005%) for 30 min (limited exposure); the antiseptic was then removed and germ tube formation of these isolates was quantified microscopically following incubation in a germ tube-inducing medium.

RESULTS

Compared with the unexposed controls, brief exposure to all concentrations of chlorhexidine gluconate suppressed the ability of the C. albicans isolates to form germ tubes in increasing order by 13.72% (p < 0.001 to p = 0.02), 46.16% (p < 0.001) and 72.46% (p <0.001).

CONCLUSIONS

These findings show that brief exposure to subtherapeutic concentrations of chlorhexidine gluconate may modulate germ tube formation of C. albicans isolates, thereby suppressing their pathogenicity, and further elucidate the pharmacodynamic mechanisms by which chlorhexidine gluconate may operate in vivo.

Use of a prefabricated tunica vaginalis fascia flap to reconstruct the tunica albuginea after recurrent penile prosthesis extrusion

PURPOSE

Although a penile prosthesis usually perforates into the urethra, it can extrude through the glans or corporeal shaft. Various materials have been used to reconstruct tunica albuginea but no method of repair has been satisfactory in such difficult cases. Repair of the weakened tunica albuginea should ideally be performed with autogenous tissues. Inasmuch as the scarred tissue bed is inadequate to ensure graft survival and no local flaps are available for this purpose, prefabrication of a local flap has been designed.

MATERIALS AND METHODS

We present 2 cases in which the distal corpus was reconstructed with a prefabricated tunica vaginalis fascia flap. The first stage involves grafting rectus fascia onto the external tunica vaginalis of the testicle. At the second stage the prefabricated tunica vaginalis fascia flap is transposed to the distal corpus, placing it as a buttress between the cylinder and urethra medially or between the cylinder and thin lateral and distal tunica albuginea. The flap also replaces part of the tunica albuginea.

RESULTS

In both patients repair of the tunica albuginea was successful and each has a functioning inflatable penile prosthesis at 2 1/2 1 1/2 years postoperatively, respectively.

CONCLUSIONS

Reconstruction of the weak tunica albuginea with a prefabricated tunica vaginalis fascia flap is an excellent procedure in these difficult cases.

Effect of various metals and calcium metabolism inhibitors on the growth of Bifidobacterium bifidum var. pennsylvanicus

In view of the facts that the normal intestinal flora exerts beneficial effects and that bifidobacteria are a more important component in the breast-fed than in the bottle-fed infant, factors affecting the growth of the latter microorganisms are of interest. A series of transition and other metals were shown to be growth inhibitors of Bifidobacterium bifidum var. pennsylvanicus. Such inhibition could be reversed fully or partially by 0.5-1.0 mM Fe2+ in the case of Zn2+, Cu2+, Au3+, Pt4+, La3+, Cr3+, Mn2+, Ni2+, and Cd2+, but not with Ag+, Hg2+, and VO2+. In addition, 2-4 mM Ca2+ substantially relieved the inhibitory effects of Zn2+, Mn2+, and La3+, and partially relieved the effects of Cd2+. Mg2+ was ineffective in relieving Zn2+ inhibition, but Ba2+ and Sr2+ could replace Ca2+ to some extent. The calcium metabolism antagonists verapamil, ruthenium red, 2-chloroadenosine, lasalocid, Ca-ionophore A-23187, and calmodulin inhibitors W-5 and W-7 inhibited microbial growth. Inhibition could be relieved fully or partially with 0.5-1 mM Fe2+. Mg2+ relieved the inhibition by lasalocid, Ca-ionophore A-23187, and verapamil, whereas Ca2+ was effective only in the case of Ca-ionophore A-23187. We conclude that calcium and magnesium fluxes play an important role in the physiology of the bifidobacteria and that several metal growth inhibitors interfere with iron metabolism.

Determination of trace elements in human serum by energy dispersive X-ray fluorescence

A system of energy dispersive X-ray fluorescence spectrometry (EDXRF) has been described to measure the concentrations of iron, copper, zinc, bromine, selenium and arsenic in human serum of healthy adults. Methods of sample preparations, standardization, and analysis have been presented. Data have been presented to show the accuracy, precision and sensitivity of the EDXRF system. The major advantages of using this system for the determination of trace elements in biological tissues are the relatively small sample size, ease of sample preparation, and the ability to perform rapid multi-element analysis on a single sample. The need for multi-element analysis has become apparent from the increased knowledge of trace element interactions in biological systems. The EDXRF system provides a solution for this need. Although the present system was applied only to the measurement of six elements, in principle the concentrations of V, Cr, Mn, Ni and Ti could also be routinely determined with improvements in technology and sensitivity.