Application of dermal microdialysis for the determination of bioavailability of clobetasol propionate applied to the skin of human subjects.

Dermal microdialysis was used to assess the bioavailability of a topical corticosteroid, clobetasol propionate, following application onto the skin of human subjects. The penetration of clobetasol propionate from a 4% m/v ethanolic solution applied onto 4 sites on one forearm of healthy human volunteers was studied. A lipid emulsion, Intralipid®, was used as the perfusate and linear microdialysis probes with a 2-kDa cutoff were inserted intradermally at the designated sites. The results indicated that Intralipid could be used as a suitable perfusate for in vivo microdialysis of this lipophilic drug of interest. Furthermore, the study clearly demonstrated the application of dermal microdialysis as a valuable tool to assess the bioavailability/bioequivalence of clobetasol propionate penetration into the skin following topical application.

Analysis of macrolide antibiotics.

The following macrolide antibiotics have been covered in this review: erythromycin and its related substances, azithromycin, clarithromycin, dirithromycin, roxithromycin, flurithromycin, josamycin, rokitamycin, kitasamycin, mycinamycin, mirosamycin, oleandomycin, rosaramicin, spiramycin and tylosin. The application of various thin-layer chromatography, paper chromatography, gas chromatography, high-performance liquid chromatography and capillary zone electrophoresis procedures for their analysis are described. These techniques have been applied to the separation and quantitative analysis of the macrolides in fermentation media, purity assessment of raw materials, assay of pharmaceutical dosage forms and the measurement of clinically useful macrolide antibiotics in biological samples such as blood, plasma, serum, urine and tissues. Data relating to the chromatographic behaviour of some macrolide antibiotics as well as the various detection methods used, such as bioautography, UV spectrophotometry, fluorometry, electrochemical detection, chemiluminescence and mass spectrometry techniques are also included.

The speed of post mortem change to the human skeleton and its taphonomic significance.

The aim of this study was to assess the potential speed of post mortem alteration to skeletal microstructure by examining human material drawn from differing environmental contexts and time periods. The material was taken from terrestrial, intertidal and lacustrine contexts and extended over a range of 3 months to 83 years post mortem. The examination was conducted using backscattered electron imaging which provided information on microstructure and relative density. The results from this study have significantly brought forward the time of known onset for post mortem alteration for 3 morphological types of microstructural change, the earliest of which was 3 months post mortem. The contribution of the depositing environment was also shown to influence significantly the microstructural/ morphological type of post mortem alteration. It is hypothesized that microstructural changes to bone could occur within days of death as a result of endogenous bacterial migration to the skeleton. Further studies are required to establish definitively the earliest moment that such change can occur prior to skeletonisation.

Effects of ethnicity and birth month on localized enamel hypoplasia of the primary canine.

Localized enamel hypoplasia of the primary canine (LHPC) is produced by a different mechanism from that causing linear enamel hypoplasia, and yet contributes disproportionately to epidemiological studies of enamel hypoplasia in childhood that do not separate the two etiological types. LHPC results from impact, probably self-inflicted by infants mouthing objects, to the unerupted primary canine crown through abnormally fenestrated cortical bone overlying the crypt. Examination of the primary teeth of ninety-six children whose mothers were enrolled in the Healthiest Babies Possible Program in Vancouver showed an average prevalence of 31 percent with LHPC (ranging from 19 percent in Vietnamese Canadians to 56 percent among Indocanadians). This is much higher than previously reported for unselected samples from Vancouver, but equivalent to studies in the USA. Mean hours of sunshine in the birth month of children with LHPC is 141.7 hours and those without is 169.4 hours; the difference is statistically significant (p = .0383). Seasonal increase in food costs and reduced availability of fresh foods containing vitamin A are thought to contribute to facial osteopenia predisposing the infant to LHPC.

Rates of putrefaction of dental pulp in the Northwest coast environment.

Cytological stability is of interest to criminal investigators in instances where remnants of soft tissue have been preserved, since such tissue can aid in the identification of human remains, helping to determine either the sex of the individual or his or her identity. This study based on seven experiments shows that, in Northwest coast outdoor environments in both summer (three experiments) and winter (three experiments), the stability of dental pulp nuclei ranges from 4 days to 2 weeks. The seventh experiment serves to describe the morphological sequence observed in nuclear putrefaction. The specimens included human and pig extracted teeth and unextracted pig teeth. Deposition of the specimens was made both on the surface and in the subsurface (30-cm depth), and the environmental variables were recorded.

Isolation of tooth pulp cells for sex chromatin studies in experimental dehydrated and cremated remains.

In experiments designed to assess sex chromatin in artificially mummified and heated pulp tissue, a method was devised that successfully separates cells while minimizing nuclear damage. Sex chromatin (both Barr bodies and F-bodies) is shown to preserve in dehydrated human pulps up to one year. Human pulp tissue retains sex diagnostic characteristics when heated to 100 degrees C for up to 1 h. Parallel experiments on extracted teeth from young pigs reveals comparable tissue preservation. Heat penetration is retarded, however, in unextracted pig teeth in fleshed jaws such that temperatures could be raised to 300 degrees C for longer than 1 h. Heat penetration into fleshed material was further tested by the insertion of thermocouple probes to assess the temperature attained within the pulp chamber. At chamber temperatures up to 75 degrees C sex diagnosis in human pulps from extracted teeth was still possible. In outdoor incineration of fleshed pigs' heads in an open fire, 75 degrees C in the pulp chamber was reached at a fire temperature within the range 500-700 degrees C. The implications of these findings for forensic situations are described.

Social and biological correlates of localized enamel hypoplasia of the human deciduous canine tooth.

Recent studies of teeth from prehistoric children have reported a localized, roughly circular patch of deficient enamel on the labial aspect of the primary canine, which reaches its highest prevalence in the Upper Paleolithic of Europe. This study reports social and biological correlates of 33 affected kindergarten-aged children from Vancouver, Canada (2.4% of 1,350 examined). Affected children can be characterized as coming from low-income families often of East Asian or Chinese origin in which there is a degree of milk avoidance and reduced breastfeeding. The defect appears to be due to minor physical trauma to the face approximately 6 months after birth occasioned by normal motor development, involving handling and mouthing objects, which damages the developing tooth crown through deficient cortical bone over the canine crypt. Reduced cortical bone in the face of the infant is attributed to nutritional factors, involving calcium deficiency, of the mother and/or developing infant.

Localized enamel hypoplasia of the primary canine.

An abnormality of enamel formation, detected only recently in living children, was found in a majority of prehistoric children, some from more than 20,000 years ago. The lesion, roughly a circular area of enamel hypoplasia approximately one millimeter in diameter, occurs on the labial surface of the primary canine tooth. A clinical examination of 2,367 school children in the Vancouver, Canada, area showed the defect occurring in fewer than one percent.

An enigmatic hypoplastic defect of the deciduous canine.

A roughly circular hypoplastic defect restricted to the labial enamel surface of the deciduous canine is described. This pathology is quite common in available samples of Upper Paleolithic and Neolithic children and a cadaver sample of recent Calcuttans, affecting 44% to 70% of individuals. It is rare in a Neanderthal sample and in children from a clinical practice in Vancouver. The lesion occurs twice as commonly in the lower jaw. The defect appears to commence at or after birth owing to localized pressure on thin or nonexistent alveolar bone overlying the bulging crypt of the deciduous canine. Population differences in the incidence of the pathology probably reflect innate and acquired variation in hard and soft tissue thicknesses in this region.