Occupational exposure to glutaraldehyde in tropical climates.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
D L Mwaniki
Publications and source records attributed to D L Mwaniki.
Fluoride sorption characteristics of different grades of bone charcoal, based on batch tests.
Although bone charcoal (char) has been recommended for use in the de-fluoridation of drinking water in developing countries, parameters relating to fluoride (F) sorption characteristics by grade or type of bone char are unclear. Based on batch tests, the rate and capacity of F uptake were highest with black grade, followed by grey grade and lowest with white grade. Twenty-four-hour contact-time F sorption isotherms indicated saturation at capacities of 11.4 mg F per g of black grade, 2.4 mg F per g of grey grade, and less than 0.3 mg F per g of white grade bone char. Additional investigations showed that F-removal efficiency of black grade char decreased steadily with increasing F concentration. Its initial sorption kinetics were dependent on particle size, and the highest sorption rate was observed with particle sizes below 0.42 mm. For maximum sorption rate, the critical mixing time was between five and 15 min. The presence of chloride anions and elevated temperatures increased the rate of F uptake by black bone-char. The pH of distilled water following contact with bone char rose to 11.5 for white bone-char, 8.3 for grey bone-char, and 7.8 for black bone-char. The effects of processing temperature on the availability of intra- and extra-apatitic F-binding sites, levels of oxides of calcium and magnesium, and the carbon content were viewed as possible causes of observed variations. These findings suggest that the black grade of bone char was the most efficacious for use in partial de-fluoridation of drinking water.
Absorption↗
A retrospective study of characteristics of impacted mandibular wisdom teeth in 110 patients treated in Nairobi, Kenya.
Analysis of 110 records of patients who presented with impacted mandibular 3rd molars was carried out to determine the frequency of occurrence of unilateral and bilateral impactions and their characteristics. 68.2% of the patients had bilateral impactions. Among the patients with bilateral impactions, 72% had mesioangular impaction occurring either bilaterally or in combination with other types of impaction. Furthermore, 38.7% mesioangular impactions were observed on the right and left sides in the patients with bilateral impactions. Among the patients with unilateral impactions 40.2% presented with mesioangular impaction, while 25.7% presented with distoangular impactions. While these observations support the general consensus regarding aetiology of mandibular 3rd molar impactions as being tooth-tissue discrepancy, the possible influence of other factors is suggested.
Adult↗
Assessment of blood compatibility of haemodialysis membranes using a miniature flat sheet dialyser.
Available pre-clinical techniques of assessing severity of untoward reaction by blood following contact with haemodialysis membranes do not account for the effects of dialysate and flow characteristics in the observed blood changes. A miniature flat sheet dialyser that considered these effects was prepared and tested in both in-vitro and ex-vivo circuits. Changes in platelets and leucocytes in heparinised human blood in-vitro tests did not distinguish regenerated cellulose (Cuprophan 150PM) membrane from a synthetic membrane, a copolymer of acrylonitrile and sodium methyl sulphonate (AN69S). Ex-vivo tests using rats showed more marked leucocyte (41.3%) and platelet (43.1%) depletion by Cuprophan 150PM than AN69S after 90 minutes of dialysis. Leucocyte and platelet loss due to AN69S were 26.9% and 13.4% respectively. In addition, Cuprophan 150PM membranes exhibited high affinity for leucocytes and platelets in both in-vitro and ex-vivo tests compared to AN69S membranes which were primarily covered with erythrocytes. Application of simulated in-use techniques in preclinical evaluation of blood compatibility membranes that are used in extra-corporeal treatment are recommended.
Acrylic Resins↗
Coping with embedded mandibular wisdom teeth in developing countries.
Despite low incidence of embedded mandibular wisdom teeth (third molars) among dental patients in developing countries (less than 100/1,000), the unfavourable patients:dentist ratios, the limited resources and low levels of public awareness render them an important problem to operators in these countries. Since the effectiveness with which they are removed largely depends on the age with respect to the stage of root formation, bone resilience and relationship with adjacent anatomical structures, and the dexterity of the operator, whenever possible, early removal is recommended. To minimise occurrence of non-operative complications that are costly to manage, primary health care workers have a vital role to play in raising levels of awareness and early referral for further evaluation. In view of the risks involved in the removal of these teeth and the small number of trained oral surgeons, continuing education to the dental practitioners, could improve their efficiency in the management of this condition.
Developing Countries↗
The position of mandibular and mental foramina in Kenyan African mandibles.
Analysis of 79 adult African mandibles indicated that 64.6% of the mandibular foramina were located below the level of the posterior extension of the occlusal plane while 30.7% were located along this plane. 56.1% of the mental foramina were located below the second premolar while 31.1% were between the second premolar and first molar. The remainder were located between the premolars. The mental foramen opened posterosuperiorly in 72.5% of the surfaces. Multiple mental foramina were found on 4.5% of the mandibles. While emphasising the importance of palpation prior to administration of mental nerve block, these observations suggest that in case of uneffective mandibular nerve block, for a significant proportion of Kenyan Bantus, attempts to place the anaesthetic solution slightly below the occlusal plane be considered.
Adult↗
Ameloblastoma after surgical removal of an impacted mandibular molar. A case report.
A case of an ameloblastoma diagnosed about 3 1/2 years after removal of an impacted mandibular 3rd molar is presented. The pre-operative radiographs, though poor in quality, showed an ill-defined radiolucency in relation to the tooth. This feature was not apparent to the examiners at the time of first presentation. Despite unfavourable working conditions in developing countries, a high level of suspicion should be maintained to avoid serious sequelae at a later stage.
Adult↗
Estimation of cost savings from reprocessing of plastic syringes. A case analysis.
Analysis of the cost of reprocessing plastic syringes in a hospital sterilization unit is considered. A simple model to estimate the cost of reprocessed syringes, showed that a syringe that had been reprocessed once was 29.8% cheaper than a new one. Reprocessing each of the 21,000 plastic syringes that are reprocessed in this unit per month once, realises savings in the order of KSh37,590 (US$ 1600). Although this unit reprocesses syringes about 10 times before disposal, the largest savings per reprocessing cycle occurred during the first 5 cycles. The cost of a reprocessed syringe does not reach its asymptotic value until after about 1,000 cycles.
Central Supply, Hospital↗
Mandibular fractures: an appraisal of the weak regions.
There is no uniformity in the role of different aetiologic factors in mandibular fractures in different cities of the world. Cultural and socioeconomic factors appear to have important contribution to the aetiologies. The condyle and the angle-body regions are most commonly fractured. There is no obvious relationship between aetiology and the site of fracture. Structural considerations suggest that differences between dentate (open section structure) and non dentate (closed section structure) regions are important determinants of fracture sites. Some modifications of standard teaching materials are recommended.
Africa↗
Occurrence and characteristics of mandibular fractures in Nairobi, Kenya.
Analysis of 355 cases with fractures of the mandible indicated that 74.9% of the cases were due to interpersonal violence and 13.8% were caused by road traffic accidents. The men to women ratio was 8.4:1 and 75.5% of the fracture cases had single fractures while 24.5% had multiple fractures. In cases with a single fracture, the most commonly involved mandibular site was the body (42.2%). The angle of mandible was most frequently fractured (50.5%) in cases with multiple fractures.
Accidental Falls↗
Evaluation of force requirements during use of recycled plastic syringes.
Forces required to withdraw the piston in recycled syringes were investigated. New disposable syringes were used as a reference. The force required in withdrawal of the piston for recycled syringes was between 3 and 8 times that required for the reference syringes. Lubrication reduced the force for the recycled syringes substantially. A modification of syringe recycling protocol is suggested.
Developing Countries↗
Fluoride binding capacity of bone charcoal and its effects on selected micro-organisms.
Water is a major source of fluoride ions in areas where skeletal and dental fluorosis are endemic. We investigated the capacity of bone char to remove fluoride from water and its effects on selected bio-indicator organisms. Under static and dynamic conditions, the capacity of bone char was in the order of 2.5 mg of fluoride per g of bone char. Bone charcoal did not appear to support growth of yeast and S. aureus. E. coli and S. faecalis counts in the filtrate decreased with time but there was substantive growth in the bone charcoal.
Bone and Bones↗
Incidence and pattern of oesophageal perforations in Kenyatta National Hospital.
A retrospective study of 42 patients with perforations of the oesophagus during the period 1981-1987 indicated that 57.1% of the perforations were iatrogenic. Diseases of the oesophagus and in contiguous structures and foreign bodies in the oesophagus caused perforations in 31% of the cases. Perforations in 35.7% of the patients were located in the middle third of the oesophagus. The lower and upper thirds were affected in 31% of the patients in each site. The presenting physical signs included tachycardia (78.6%), fever (76.2%) and dyspnoea (59.5%). The main accompanying symptoms were chest pain and coughs in 100% and in 50% of the patients respectively. Radiographic findings showed hydropneumothorax in 40.5% of the cases and consolidation in 38.1% of the patients. Oesophagoscopy was positive in 78% of cases tested while thoracocentesis was positive in all cases that were tested.
Adolescent↗
Evaluation of physical-mechanical properties of 3 brands of plaster of Paris in the Kenyan market.
In this study, 3 brands of plaster of Paris that are available in the Kenyan Market for prosthetics and dental rehabilitation uses were subjected to physical-mechanical tests. The particles in two of the brands that had been imported were finer than a locally made plaster since less than 1.41% of their particles were larger than 150 microns compared to 15.2% in the local plaster. The range of their setting times was between 7.5 and 27.5 min. and was within the International Standards Organisation (ISO) recommendation. The water:power ratios required to produce plaster mixes of standard consistency for the locally made plaster was about 1.5 times of other brands. In compression, the mean 1-hour strength of local plaster was 2.5 MN/m2 (Mega Newtons per square metre) compared to 6.81 MN/m2 and 8.95 MN/m2 for the other brands. The differences between these strength values were highly significant (p less than 0.01). There were no significant differences in deformation of fracture for the 3 brands whose range was 1.32% to 1.71%. In order to obviate the need to import plaster, strict manufacturing techniques of locally made plaster are recommended.
Calcium Sulfate↗