[Survey of methods of cleaning, decontamination, disinfection and sterilization in dental health services in tropical areas]. / Enquête sur les méthodes de nettoyage, décontamination, désinfection et stérilisation dans des services dentaires en zone tropicale.

The International Aid for Ontology (IAO) carried out this survey of hygiene in the dental health services of 5 French-speaking African countries in 1994, in association with the Faculty of Pharmaceutical and Biological Sciences of Paris. This study received support from the World Health Organization (WHO), the French Ministry for Cooperation and the European Community and the Ivory Coast Oral and Dental Hygiene and Health Committee (CIHSBD). Twenty-nine dental services from Benin (3), Burkina Faso (6), Ivory Coast (12), Mali (5), Niger (3) participated in this survey which gives an insight into the daily hygiene routines of these services. The cleaning, decontamination, disinfection and sterilization procedures for premises, dental equipment, instruments, hands and disposable items were investigated. No individual protocols are reported. Bench tops were cleaned or disinfected daily in 73% of centers and floors were cleaned or disinfected daily in 59% of centers. Walls were cleaned once per week in 44% of the centers. Hands were always washed between patients, with 68% of dental surgeons using only solid or liquid cleansing soaps and the others using antiseptic or disinfectant solutions. The dentist's chair was cleaned or disinfected daily in 68% of centers, mostly with soap (43%) or diluted bleach (23%). Vacuum equipment was cleaned with soap (50%) or diluted bleach (57%), with some surgeries using a combination of the two. Hand pieces and turbines were cleaned and disinfected after each use with alcohol (35%) or diluted bleach (26%) and were sterilized in 9% of centers. Instruments were sterilized with a Poupinel (63%), unspecified sterilizer (26%), autoclave (7%) or low temperature disinfection procedure (4%). Instruments were regularly sterilized in all centers. Single-use disposable items were often reused: 88% of centers reused gloves, 64% anesthetic cartridges and 32% disposable needles. This survey demonstrates that dentists do attempt to achieve appropriate hygiene standards despite difficult practice conditions, exacerbated by supply problems. In all applications, hygiene involves a succession of closely-related, logical steps, which form an asepsis chain aimed at preventing the transmission of infection. Our survey shows that fundamental elements of hygiene require attention to achieve this aim. The cleaning, disinfection and sterilizing of floor surfaces and equipment should be improved and more widespread use made of disposable items. It is important to define the hygiene level required for particular treatments, taking into account the oral and dental micro flora and whether the equipment has been decontaminated, disinfected or sterilized. A piece of equipment is decontaminated if it has been mechanically cleaned and decontaminated. It is disinfected if these steps are followed by rinsing with sterile water, drying and conditioning. An item is described as sterilized if it is cleaned, decontaminated, rinsed, dried, conditioned and then sterilized. We found that a wide variety of chemicals were used to clean hands, surfaces and equipment. The nature and appropriate methods of use of these chemicals were not widely known. Understanding the chemical composition of these chemicals makes it possible to classify them into cleaning agents, detergents, decontaminating agents and disinfectants. The definition, choice and use of antiseptics and disinfectants should be strictly controlled. It is also vital that single-use disposable items are used only once and are never reused. Hygiene in the dental surgery is a chain of processes aimed at protecting the patient and the medical staff. There are many links in the chain, involving floor and surface hygiene, hand washing by dentists and dental assistants, washing of surgery linen and treatment of equipment. Dental practitioners should continually focus on ensuring that the chain of hygiene procedures is not broken, in their own interests as well as in those of their patients.

Cefpodoxime-proxetil hydrolysis and food effects in the intestinal lumen before absorption: in vitro comparison of rabbit and human material.

The luminal and mucosal deesterification of the prodrug ester cefpodoxime-proxetil was studied in human duodenal washings in vitro. Enzymatic hydrolysis of the ester, releasing the active third generation cephalosporin, was observed in luminal washing in the same way as it had previously been observed in the rabbit. Eserine and PMSF and HgCl(2) were potent inhibitors of cefpodoxime-proxetil hydrolysis in luminal washing, suggesting the participation of a cholinesterase in the hydrolysis of cefpodoxime-proxetil. These results are in agreement with our previous findings performed in the rabbit. Moreover, cefpodoxime-proxetil directly decreases the acetylcholinesterase activity when tested by a specific enzymatic method. These observations support the hypothesis that the partial oral bioavailability of cefpodoxime-proxetil results from hydrolysis by luminal cholinesterases. In vitro experiments run with rabbit duodenal washing with food components were compared with the pharmacokinetics of cefpodoxime-proxetil in humans. Amino acids, trace elements and vitamins were potent inhibitors for cefpodoxime-proxetil hydrolysis in duodenal washings. Otherwise, lipids (LTC and mixed LCT/MCT) did not interact. In the human, cefpodoxime-proxetil bioavailability is significantly enhanced when tablets are administered with food. The correlation found between animal results and human results in vitro for prospective investigation of a new prodrug ester could be very useful. An in vitro hydrolysis in intestinal animal washings could allow the potentially degraded condition and the food effect of the luminal tract to be assessed before absorption.

Cefazolin serum protein binding and its inhibition by bilirubin, fatty acids and other drugs.

This paper describes the protein binding of cefazolin to human serum and to human serum albumin (HSA) using equilibrium dialysis. The drug is exclusively bound to HSA with a moderate affinity, Ka = 16,600 +/- 1600 M-1, and one saturable binding site, n = 0.73 +/- 0.02. Moreover cefazolin shows a dose-dependent binding leading a possible increase of the free fraction (when its total concentration increases). This antibiotic is displaced by free fatty acids (FFA) and bilirubin. Cefazolin binding to human serum and human serum albumin (HSA) was studied in presence of acidic drugs. At low concentrations clofibric acid and phenylbutazone both exhibiting high affinity for HSA displace strongly cefazolin. Valproic and salicylic acids, sulfamethoxazole, cefoperazone which have approximately the same affinity as cefazolin, must be used at higher concentrations to displace this antibiotic. A particular phenomenon was observed with cefazolin on HSA when associated with furosemide. A low concentration (5-25 microM) of this drug induces a positive cooperativity of binding between cefazolin and HSA. But at a molar ratio of furosemide to albumin greater than one, such cooperative interaction disappears and a competitive inhibition of cefazolin binding occurs. For all drugs studied, a competitive inhibition was found except for tryptophan. Finally, it is concluded that cefazolin shares the warfarin binding site on HSA.

Binding of cefalotin to human serum albumin.

Binding of cefalotin to human serum albumin was studied in vitro by equilibrium dialysis and the quantitative measurement of cefalotin was made by fluorimetric assay. The binding rate of cefalotin to human serum albumin found to be 61,1%. The determination of drug binding parameters showed a large number of binding sites (n = 9.36) and a moderate affinity (K = 3898 M-1).