Primary tooth emergence in Australian children: timing, sequence and patterns of asymmetry.

BACKGROUND: Information on the timing and sequence of human tooth emergence is valuable when analysing human growth and development, predicting the age of individuals, and for understanding the effects of genetic and environmental influences on growth processes. This paper provides updated data on the timing and sequence of primary tooth emergence in Australian children for both clinicians and researchers. METHODS: Twins were recruited from around Australia with data collected through parental recording of twins' primary tooth emergence. One twin from each pair was then randomly selected to enable the calculation of descriptive statistics for timing, sequence and asymmetry in tooth emergence. RESULTS: The first and last primary teeth emerged, on average, at 8.6 months and 27.9 months, respectively, with teeth emerging in the order: central incisor, lateral incisor, first molar, canine, second molar. Left-side antimeric teeth were more likely to emerge before their right-side counterparts but this was not statistically significant. At least 35% of all antimeric pairs had emerged within two weeks of each other, serving as a useful guideline for assessing symmetrical versus asymmetrical development. CONCLUSIONS: Primary tooth emergence in Australian twins is occurring later than reported previously for Australian singletons but is consistent with findings for singletons in other ethnic groups. The most common sequence of primary tooth emergence appears to be consistent in twins and singletons and has not changed over time.

Patterns of asymmetry in primary tooth emergence of Australian twins.

AIMS: This study is part of a larger investigation of genetic and environmental influences on primary tooth emergence in Australian twins. Our aims were to describe patterns of emergence asymmetry, including directional and fluctuating components (DA, FA), and to test for a genetic basis to observed asymmetry. METHODS: The study sample consisted of 131 twin pairs. Using one randomly-selected twin from each pair, dental asymmetry was examined by analysing the number of days between emergence of antimeres (Delta), with dates of emergence provided through parental recording. Scatterplots were used for assessment of DA and FA, followed by paired t-tests to detect significant differences in mean Delta from zero (evidence of DA). FA was assessed by calculating means and variances of the absolute value of Delta. A range of intervals (0, 7, 14, 21, 28 days) was used to define symmetrical emergence of antimeres. RESULTS: Although a trend in left-side advancement for tooth emergence was detected, this was not statistically significant. Relatively low levels of FA were noted through -out the primary dentition, with maxillary and mandibular lateral inisors displaying the highest values, but no evidence of a genetic influence on FA was noted. Around 50% of all antimeric pairs of primary teeth were found to emerge within 14 days of each other, although time differences of more than 50 days were noted in some cases. CONCLUSION: Studies of dental asymmetry provide insights into the biological basis of lateralisation in humans and the results can also assist clinicians to discriminate between normal and abnormal developmental patterns.

Energy and nutrient status of amenorrheic athletes participating in a diet and exercise training intervention program.

Chronic energy deficit is one of the strongest factors contributors to exercise-induced menstrual dysfunction. In such cases, macro- and micronutrient intakes may also be low. This study presents the results of a diet and exercise training intervention program. designed to reverse athletic amenorrhea, on improving energy balance and nutritional status in 4 amenorrheic athletes. The 20-week program provided a daily sport nutrition supplement and 1 day of rest/week. The program increased protein intakes for the 3 athletes with a protein deficit to within the recommended levels for active individuals. Micronutrient intakes increased, as did serum concentrations of vitamin B12, folate, zinc, iron, and ferritin. These results indicate that some amenorrheic athletes have poor nutritional status due to restricted EIs and poor food selections. A sport nutrition supplement may improve energy balance and nutritional status in active amenorrheic women.

Modulation of HLA class I antigen and ICAM-2 on endothelial cells after in vitro infection with human cytomegalovirus.

The aim of the present work is to investigate the expression of HLA class I antigen and intercellular adhesion molecule-2 (ICAM-2) on the surface of human umbilical cord endothelial cells (HUVEC) after infection with human cytomegalovirus (HCMV). The expression of HLA class I antigen and ICAM-2 were determined (using antibodies against HLA class I antigen and ICAM-2) by attachment inhibition assay and flow cytometric analysis. Attachment inhibition assay demonstrated that HCMV increased the expression of HLA class I antigen. This was confirmed by flow cytometric analysis, which showed an increase in HLA class I antigen expression on HCMV-infected HUVEC. The results of the expression of ICAM-2 using attachment inhibition assay revealed that ICAM-2 is involved significantly in the increased adhesion of T lymphocytes to HCMV-infected HUVEC. However, flow cytometric analysis revealed that there were no changes in the expression of ICAM-2 on HCMV-infected HUVEC. One possible explanation for this is that HCMV induces the activation of ICAM-2 on the surface of HCMV-infected endothelial cells without affecting its expression.

Human cytomegalovirus infection induces mRNA expression and secretion of plasminogen inhibitor type-1 in endothelial cells.

The aim of the study was to investigate whether infection of endothelial cells with human cytomegalovirus (HCMV) perturbs expression and production of plasminogen activator inhibitor type-1 (PAI-1). mRNA expression of PAI-1 was investigated by isolating total RNA from HCMV-infected and control cells, followed by Northern blotting and probing with 32P-labelled PAI-1 probe. Sandwich ELISA was used to investigate PAI-1 production. HCMV induced the expression of PAI-1-mRNA at 2-5 days postinfection (maximum expression was at 3 days postinfection which was 40% higher than control). HCMV also induced secretion of PAI-1 at 2-5 days postinfection. These results indicate that infection of endothelial cells with HCMV disturbs PAI-1 expression and production in these cells.

Alteration in the expression of endothelial cell integrin receptors alpha 5 beta 1 and alpha 2 beta 1 and alpha 6 beta 1 after in vitro infection with a clinical isolate of human cytomegalovirus.

Human cytomegalovirus infection of human umbilical vein endothelial cells reduces the ability of these cells to bind to fibronectin, collagen type IV and laminin. This suppression requires active virus, since UV-inactivated virus did not alter the binding ability of these cells to adhere to fibronectin, collagen type IV, and laminin. In an attempt to elucidate the molecular mechanism of this altered interaction, the surface expression of alpha 5 beta 1, alpha 2 beta 1, alpha 3 beta 1, and alpha 6 beta 1 integrins on cytomegalovirus-infected endothelial cells was examined using attachment inhibition assay and flow cytometric analysis. The results presented here show that infection with human cytomegalovirus selectively alters the expression of integrin on human endothelial cells, with the ability to induce downregulation of alpha 5 beta 1 and alpha 2 beta 1 (p = 0.001) and p = 0.03, respectively), while significantly upregulating alpha 6 beta 1 (p = 0.03), and marginally upregulating alpha 3 beta 1 (p = 0.05).

Comparison of the infectivity of the laboratory strain AD169 and a clinical isolate of human cytomegalovirus to human smooth muscle cells.

The results displayed by human cytomegalovirus (HCMV) IE/E antigen expression and virus release into the supernatant at various times post infection with a clinical isolate (C3/p5) and AD169 laboratory strain of HCMV, illustrated differences in the biology of these viruses on the various cell lines. While AD169 strain was shown to infect fibroblasts efficiently, it showed a low infectivity profile to smooth muscle cells, whereas C3/p5 displayed comparable infectivity characteristics on both cell lines. Neither virus demonstrated propensity for infecting endothelial cells, although passaging of the C3/p5 for additional 11 passages in endothelial cells provided virus capable of infecting endothelial cells efficiently. These results show that HCMV is capable of infecting smooth muscle cells which could be of relevance to the proposed role of HCMV in atherogenesis and provides further evidence on the adaptation of AD169 to fibroblasts.

Alterations in the expression of ELAM-1, ICAM-1 and VCAM-1 after in vitro infection of endothelial cells with a clinical isolate of human cytomegalovirus.

Human cytomegalovirus (HCMV) infection of endothelial cells resulted in increased adhesion of the cells to peripheral blood leukocytes. It was demonstrated by flow cytometry that increased adhesiveness parallels the increased expression of cell surface adhesion molecules (ELAM-1, ICAM-1, VCAM-1). The increased adhesion of PMN and T-lymphocytes was due to upregulation in the expression of ELAM-1 and ICAM-1. The upregulation of VCAM-1 resulted in the increased adhesiveness of monocytes and T-lymphocytes to HCMV-infected HUVEC. The increased adhesiveness to leukocytes was caused by HCMV replication since endothelial cells exposed to HCMV-free supernatants and UV-inactivated HCMV did not show any increase in adhesiveness to any of the leukocytes tested.

Cytomegalovirus infection of vascular endothelial cells alters production of GM-CSF and G-CSF.

Infection of human umbilical vein endothelial cells with the clinical isolate of human cytomegalovirus (HCMV; at a multiplicity of infection of 2) severely suppresses the production of granulocyte-CSF and granulocyte-macrophage-CSF at late stages of infection (6 days post infection onwards). The effect was produced by actively multiplying virus which indicates that HCMV antigen expression is important for this suppression. The suppression in the production of these two cytokines was not due to their accumulation inside the cell nor to cell damage or lysis after infection.

The validation of short tandem repeat (STR) loci for use in forensic casework.

A quadruplex reaction has been developed which amplifies the short tandem repeat (STR) loci HUM-VWA31/A, HUMTHO1, HUMF13A1 and HUMFES/FPS. Detection of the PCR products employs denaturing polyacrylamide gels coupled with fluorescent-based technology. This system has been evaluated for use in routine forensic casework and has been shown to be both robust and reproducible. The quadruplex reaction is as sensitive as the commercially available HLA DQ alpha Amplitype typing system and can be used on both degraded and aged material. The problems of environmental contamination have been shown to be limited provided strict procedural practices are followed-i.e. physical separation of sample extraction and amplified products; the use of dedicated equipment such as pipettes; the separation of amplification preparation area. The ability of the system to detect mixtures and the successful analysis of case stains has shown that this system is well suited as a tool for forensic investigation.

Interleukin-1 production and cell-activation response to cytomegalovirus infection of vascular endothelial cells.

Human cytomegalovirus (HCMV) is a source of major complications in immunosuppressed individuals, and endothelial involvement in HCMV infection is well documented. Traditionally laboratory strains of HCMV have been used in experimental investigations in vitro; however the continuous propagation of these strains in fibroblasts have attenuated the virus making it unsuitable for infecting other cell systems such as endothelial cells. In this study a recent clinical isolate of HCMV was propagated through several passages in endothelial cells and was used to investigate the effect of HCMV infection of human umbilical vein endothelial cells (HUVEC) on IL-1 production and cell proliferation. Infection of HUVEC with the clinical isolate of HCMV (at multiplicity of infection 5:1) suppressed the production of IL-1 alpha (82%) and IL-1 beta (99%) at 5 h post infection; the levels returned to that of the control within 24h post infection. Ultraviolet inactivated (but not heat killed) virus produced similar suppression confirming that a thermolabile viral structural protein or intact virion were responsible for this suppression. Infection of HUVEC with the clinical isolate increased the number of these cells and the rate of their proliferation. An increase of infected HUVEC number under quiescent growth conditions continued as the infection progressed (6-10 days post infection), exhibiting, at 3 days post infection, 5 times the number of uninfected HUVEC (control) which did not tolerate the quiescent culture conditions for more than 4 days. Live virus is responsible for this increase because UV-inactivated virus did not maintain the proliferation of HUVEC. These studies suggest that while infection of HUVEC with a recent clinical isolate of HCMV suppressed the production of IL-1 at early hours after infection, it increased the proliferation of these cells at later stages of infection.

Increased cytomegalovirus infection of human fibroblast and endothelial cells by electroporation.

Electroporation of fibroblasts and endothelial cells in the presence of HCMV caused an increase in the infection of these cells by the virus. This method could be applied to cells that are difficult to infect by ordinary laboratory methods and also in cases when synchronized infection of the cells by the virus is needed.

A report of an international collaborative experiment to demonstrate the uniformity obtainable using DNA profiling techniques.

This paper describes a collaborative exercise intended to demonstrate whether uniformity of DNA profile results could be achieved between different European laboratories. It was shown that this goal can be obtained provided that a common protocol is followed (specifically the use of a common electrophoretic buffer as being the most important parameter). Generally, lower molecular weight loci (with lower molecular weight fragments) such as YNH24 perform better than higher molecular weight loci such as MS43a. The results of the exercise are discussed in relation to the objectives of the European DNA profiling group (EDNAP).

Databases, quality control and interpretation of DNA profiling in the Home office Forensic Science Service.

The history of DNA profiling in the Home Office Forensic Science Service began with the introduction of multilocus probes into casework in 1986. The use of single-locus probes was introduced in 1990, supported by databases of three ethnic groups; interpretation is backed up using a Bayesian approach. Databases were compiled using an image analysis computing system. Quality control systems are described, detailing requirements before a sample can be included in the database.

Population genetics of four hypervariable loci.

Populations of white Caucasians, Afro-Caribbeans and Asians residing within the UK have been analysed at 4 different hypervariable loci. A computerised system was used to store and to analyse the data. Simulation experiments were carried out in order to determine whether there was any evidence for population stratification, which would lead to non-independence of allelic distributions.

Report of a European collaborative exercise comparing DNA typing results using a single locus VNTR probe.

A collaborative exercise was carried out in 1989 among 12 European forensic laboratories using the single locus VNTR probe pYNH24, the restriction enzyme HinfI, the same set of human genomic DNA samples, and a standardized DNA size marker. The objectives of the exercise were: (1) to study the degree of variation within and between laboratories, (2) to obtain information on requirements for technical standardization allowing the exchange of typing results and (3) to compare different approaches for the identification of allelic DNA fragments of unknown size. Each laboratory carried out up to 10 independent typing experiments using the same DNA samples. The results were analysed independently by two laboratories using three different methods. The results of the exercise demonstrate the correlation of typing that can be achieved within and between laboratories under conditions of minimal standardization.

Population genetics of four hypervariable loci

Populations of white Caucasians, Afro-Caribbeans and Asians residing within the UK have been analysed at 4 different hypervariable loci. A computerised system was used to store and to analysed the data. Simulation experiments were carried out in order to determine whether there was any evidence for population stratification, which would lead to non-independence of allelic distributions. (AU)