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In this study, the nucleotide sequences of the mitochondrial DNA hypervariable region II (HVRII) and inter HVR in the Thai population were investigated. Buccal swab samples were randomly collected from 100 unrelated healthy individuals residing in Thailand. The analysis of HVRII revealed a total of 65 different haplotypes of which 47 were unique and 18 were found in more than one individual. The most frequent haplotype observed was A73G-A249D-A263G-309.1C–315.1C (7%). Nucleotide transition from adenine (A) to guanine (G) was the most frequent substitution. Nucleotide transversions were also observed but with a lower frequency compared to nucleotide transitions. Insertions of C (57%), CC (14%), and CCC (1%) were found at position 309. Twenty-six samples were found to exhibit nucleotide deletion at position 249. The haplotype diversity, random match probability, and discrimination power were calculated to be 0.9859, 0.0240, and 0.976 respectively. In addition, the outside HVR fragment within the control region at positions 16381–72 (inter HVRI/HVRII) and 341–437 (inter HVRII/HVRIII) were sequenced in order to examine the polymorphic sites. High polymorphism was found at positions 16519, 150, 249, and 309. It was concluded that the nucleotide sequence variations in HVRII and inter HVRI/HVRII would be useful for forensic identification.

Blow flies are worldwide the most important insects from a forensic point of view. In Thailand, aside from the two most common species, Chrysomya megacephala (F.) and Chrysomya rufifacies (Macquart), Chrysomya chani Kurahashi was also found to be of forensic importance. We present a case of a human female cadaver in its bloated stage of decomposition, discovered at Pachangnoi Subdistrict, northern Thailand. Entomological sampling during the autopsy displayed an assemblage of numerous dipteran larvae. Macroscopic observations showed the coexistence of third instar larvae of the three blow flies C. megacephala, Chrysomya villeneuvi Patton, an unknown blow fly species and one muscid, Hydrotaea sp. The minimum post-mortem interval was estimated to be six days, based on the developmental rate of C. megacephala. The ID of the unknown larva, which is the focus of this report, was revealed later as C. chani by DNA sequencing, using a 1205 bp of cytochrome c oxidase subunit I (COI). The occurrence of C. chani on a human body revealed the need to analyse and describe the morphology of its immature stage, to enable forensic entomologists to identify this fly species in future cases. The morphological examination of the third instar was performed, revealing peculiar characteristics: protuberant tubercles encircling abdominal segments; 9–11 lobes on the anterior spiracle; six prominent pairs of tubercles along the peripheral rim of the eighth abdominal segment; a heavily sclerotized complete peritreme of the posterior spiracles. A key to differentiate the third instar of blow flies of forensic importance in Thailand is provided.

Mitochondrial DNA (mtDNA) analysis has displayed an important role and been considered as a powerful tool in various fields of forensic science applications. Nowadays, single nucleotide polymorphisms (SNPs) on mtDNA have become additional DNA markers when conventional STR typing practically fails. mtDNA sequencing of polymerase chain reaction (PCR) products from the hypervariable region I (HVRI) and II (HVRII) is the standard method of mtDNA analysis. However, mtDNA sequencing is rather expensive, time consuming and technically complex. This study aims to develop the SNPs minisequencing for screening of Thai populations. For this purpose, sixteen SNPs that possess high discriminating power in hypervariable regions were selected. The DNA samples were obtained from 100 buccal swab samples of Thai healthy individuals. All DNA samples were extracted and were subsequently amplified by single duplex PCR technique. The duplex PCR products were genotyped by SNPs minisequencing. Based on 16 SNPs, a total of 63 haplotypes were observed of which 46 haplotypes were unique. The haplotype diversity, discriminating power and random match probability were calculated to be 0.9830, 0.9732 and 0.0268, respectively. The SNPs at 150, 199, 489, 16129, 16189, 16223, and 16304 were highly polymorphic in the studied population. Our results suggested that the SNPs minisequencing can be an alternative method of SNPs genotyping. This method can be used for an exclusion of a large number of mismatch samples and as a presumptive test prior to do confirmatory mtDNA sequencing.

Lymphoid interstitial pneumonitis (LIP), a frequent pulmonary complication in human immune deficiency virus (HIV)-infected pediatric patients, is characterized histologically by marked infiltration of lymphoid cells. Several theories have been suggested that LIP may be caused by Epstein-Barr virus (EBV). To identify the reservoir of EBV and pathogenesis of lymphoid infiltrates in HIV subtype E infected pediatric LIP, we examined the distribution and expression of EBV in the inflammatory cell recruitment in surgical lung biopsy-proven LIP from 9 vertically HIV subtype E-infected pediatric patients. The dominant microscopic feature of LIP demonstrated widespread widening of alveolar septum by mononuclear inflammatory cell infiltrate mainly composed of mature lymphocytes and plasma cells surrounding airways and expanding to the lung interstitium. EBV-encoded RNA (EBER) in situ hybridization, performed from paraffin-embedded lung tissues, revealed positive intranuclear signals in all 9 LIP cases. Interestingly, combined immunohistochemical and in situ hybridization analyses in 6 out of 9 LIP cases revealed 30% to 50% of the Langerhans and related dendritic cells were infected with EBV, whereas

Objective: This research investigated the polymorphism of the X-chromosomal short tandem repeats (X-STR) DXS8377 in Northern Thai males. Methods: Genomic DNA was extracted from blood or buccal cells of 200 unrelated healthy individuals using Nucleospin® Blood or Nucleospin® Tissue (Macherey-Nagel), respectively. The DXS8377 locus was amplified by polymerase chain reaction (PCR) and the PCR product was analyzed by agarose gel electrophoresis. The allelic ladder was constructed and the size of all PCR products was analyzed by polyacrylamide gel electrophoresis using allelic ladder as a marker. The nucleotide sequences of the different-sized PCR products were analyzed to identify the DXS8377 alleles. Lastly, the Polymorphic information content (PIC) and Power of discrimination (PD) of DXS8377 DNA marker were calculated and the analysis of population relationships was performed using chi-square test of homogeneity. Results: Eleven DXS8377 alleles were observed in the study population, the allele 49 was the most frequent with the allele frequency of 0.4400. According to previous studies, allele 49 was found in all of the populations studied and it was common among various populations. The polymorphism and the probability of DXS8377 to discriminate two unrelated individuals were moderate with a PIC and PD of 0.6973 and 0.7305, respectively. Most interestingly, the DXS8377 DNA marker was able to differentiate Mongoloid from Caucasoid and Negroid and it was also able to differentiate Northern Thai males from other Asian populations, including Korean, Japanese and Chinese. Conclusion: Even though DXS8377 possessed moderate PIC and PD, this DNA marker was able to differentiate Mongoloid from Caucasoid and Negroid and it was also able to differentiate Northern Thai males from Korean, Japanese and Chinese.

This paper presents and discusses 30 cases of cadavers that had been transferred for forensic entomology investigations to the Department of Forensic Medicine, Faculty of Medicine, Chiang Mai University, northern Thailand, from 2000 to 2006. Variable death scenes were determined, including forested area and suburban and urban outdoor and indoor environments. The fly specimens found in the corpses obtained were the most commonly of the blow fly of family Calliphoridae, and consisted of Chrysomya megacephala (F.), Chrysomya rufifacies (Macquart) Chrysomya villeneuvi Patton, Chrysomya nigripes Aubertin, Chrysomya bezziana Villeneuve, Chrysomya chani Kurahashi, Lucilia cuprina (Wiedemann), Hemipyrellia ligurriens (Wiedemann), and two unknown species. Flies of the family Muscidae [Hydrotaea spinigera Stein, Synthesiomyia nudiseta (Wulp)], Piophilidae [Piophila casei (L.)], Phoridae [Megaselia scalaris (Loew)], Sarcophagidae [Parasarcophaga ruficornis (F.) and three unknown species], and Stratiomyiidae (Sargus sp.) were also collected from these human remains. Larvae and adults of the beetle, Dermestes maculatus DeGeer (Coleoptera: Dermestidae), were also found in some cases. Chrysomya megacephala and C. rufifacies were the most common species found in the ecologically varied death scene habitats associated with both urban and forested areas, while C. nigripes was commonly discovered in forested places. S. nudiseta was collected only from corpses found in an indoor death scene.

This study analyzed the nucleotide sequences of the hypervariable region III (HVRIII) of mitochondrial DNA in Thai individuals. Buccal swab samples were randomly obtained from 100 healthy, unrelated, adult (18-60 years old), volunteer donors living in Thailand. Eighteen different haplotypes were found, of which 11 haplotypes were unique. The most frequent haplotypes observed were 522D-523D. Nucleotide transition from Thymine (T) to Cytosine (C) at position 489 (43%) was the most frequent substitution. Nucleotide transversions were also observed at position 433 (Adenine (A) to C, 1%) and position 499 (Guanine (G) to C, 1%). Fifty-three samples presented nucleotide insertion and deletion of C and A (CA) at position 514-523. Insertion of 1AC (3%) and 2AC (2%) were observed. Deletion of 1CA (53%) and 2CA (2%) at position 514-523 were revealed. The deletion of T at position 459 was observed. The haplotype diversity, random match probability, and discrimination power were calculated to be 0.7770, 0.2308, and 0.7692, respectively.

In Thailand, the predominant HIV subtype is E, rather than subtype B as in North America and Europe. Subtype E has the ability to replicate in vitro in Langerhans cells. We hypothesized that this cell type might constitute a reservoir for the HIV virus in infected lymph nodes. We examined lymph nodes from 25 HIV-1 subtype E-infected patients to determine the immunophenotype of HIV-1-infected cells, their numbers and their distribution. The presence of HIV was detected either by in situ reverse transcriptase-polymerase chain reaction or immunoperoxidase. Cell identity was determined by double labelling using alkaline phosphatase-based immunohistochemistry. The majority of HIV-infected cells in the lymph nodes were Langerhans cells (CD1a+S100+) and Langerhans-related dendritic cells (p55+S100+). These cells were located in the paracortical areas of lymph nodes, with a few cells scattered at the edges of germinal centers, but were absent from germinal centers themselves, in contrast to the reported distribution of subtype B virus. In addition, multinucleated giant cells were significantly more common in HIV-infected nodes (64%) compared to controls (4%) (P=0.00002). In conclusion, Langerhans histiocytes and related cells are reservoirs for HIV subtype E in lymph nodes. Disrupting the pathway of infection of Langerhans cells and related cells may be a viable strategy to interfere with transmission of HIV subtype E.

Antiretroviral treatment with zidovudine (ZDV) from the 14th week until the end of pregnancy has markedly reduced the vertical transmission rate of HIV-1 in Europe and North America. A shorter duration of treatment has reduced this rate in Africa and Southeast Asia to a lesser degree. In Southeast Asia, subtype E is the major subtype rather than subtype B as in Western countries. The goals of this study were to determine the optimal duration of ZDV prophylaxis for subtype E and to confirm its effectiveness at the histologic level. Fifty pregnant women seropositive for HIV-1 subtype E were given ZDV prophylaxis consisting of 300 mg administered twice daily, switching to 300 mg administered every 3 hours from the onset of labor until delivery. Twenty-seven received "short-term" ZDV lasting 14 to 35 days before delivery, whereas the other 23 received "long-term" ZDV lasting 62 to 92 days. The effectiveness of ZDV prophylaxis was assessed by detection of HIV-1 in the placenta using in situ polymerase chain reaction (PCR). All babies in this study were tested up to one year of age. Three were not positive until after one month of age, but one was positive as a neonate. Four neonates were positive for HIV-1 as detected by PCR on peripheral blood, including one in the neonatal period. All cases were from the short-term prophylaxis group. Decidual glandular epithelial cells were the only cell type in the placenta that expressed HIV proviral DNA under ZDV prophylaxis. Sixty-seven percent of placentas in the short-term ZDV group showed more than occasional positive cells compared with 22% in the group receiving long-term ZDV prophylaxis (P < 0.02). This is first study to compare the effectiveness of short-term and long-term ZDV prophylaxis with respect to the presence of HIV in the placenta. Our study shows that longer (at least 60 days) prophylaxis is more effective in reducing HIV expression in the placenta and is associated with reduced transmission to neonates.

The presence of p24 protein was studied in lymph nodes from human immunodeficiency virus (HIV)-positive patients affected by persistent generalized lymphadenopathy. Paraffin-embedded lymph node sections from 50 HIV-1 subtype E-infected lymph nodes from patients in Thailand and 25 HIV-1 presumably subtype B-infected lymph nodes from patients in the United States were immunostained with p24 HIV major core and capsid monoclonal antibodies using the streptavidin-biotin immunoperoxidase technique. Positivity for HIV p24 protein was detected in 20 of 22 HIV-1 subtype B infected nodes in which lymphoid follicles were present, with p24 staining demonstrating a reticular pattern within the germinal centers. Interestingly, no case from 50 clade E-infected lymph nodes containing lymphoid follicles had such a reticular pattern in the germinal centers. This difference could be explained by differential infection of subsets of dendritic cells by the two HIV-1 clades, or perhaps by different routes of initial HIV-1 transmission.

In Thailand, the predominant HIV subtype is E, rather than Subtype B as in North America and Europe, and the predominant mode of transmission is heterosexual contact. Subtype E has the ability to replicate in vitro in Langerhans cells. We hypothesized that this cell type might constitute a reservoir for the HIV virus in vaginal mucosa of asymptomatic carriers. To examine this hypothesis, we compared vaginal tissue histology in HIV-1-seropositive cases with seronegative cases and determined the immunophenotype of HIV-1-infected cells, their numbers, and their distribution in vaginal mucosa. Vaginal biopsies were performed at four different sites from six asymptomatic HIV-1 Subtype E-infected persons and from six seronegative cases at necropsy and examined histologically. Immunophenotyping was performed using immunoperoxidase for Gag p24 HIV, CD3, CD20, CD68, CD1a, S-100 and p55 antigens and by double labeling, combining immunoperoxidase with alkaline phosphatase using pairs of the above antigens. Twenty of twenty-four vaginal biopsies (83.3%) from HIV-seropositive cases showed definite inflammation compared to five of twenty-four vaginal necropsies (20.8%) from HIV-seronegative cases. One third of HIV-seropositive biopsies (8/24) demonstrated p24-positive cells in the epithelium, whereas three-fourths (18/24) of the biopsies revealed p24-positive cells in the lamina propria. All seropositive patients showed positive cells in at least one biopsy, but not all biopsies contained positive cells. Infected cells were more frequently observed at sites of greater inflammation. The dendritic cell count in HIV-seropositive vaginal epithelium was significantly higher than that observed in the seronegative cases (P =.004). The majority of p24-positive cells in the vaginal epithelium were Langerhans cells (CD1a+/S-100+), whereas in the lamina propria, about half of p24-positive cells were Langerhans-related dendritic cells (p55+ and S-100+) and half were T lymphocytes. In conclusion, the increased propensity for heterosexual transmission of Subtype E may be related to vaginal inflammation, leading to the accumulation of Langerhans cells and related dendritic cells which, once infected with HIV, can act as a reservoir for further virus transmission.

Nine STR loci (D3S1358, D5S818, D7S820, D8S1179, D13S317, TH01, VWA, TPOX, LPL) were studied in a large Northern Thai population sample. All loci meet Hardy-Weinberg expectations. The combined power of discrimination and exclusion is 0.9999999979 and 0.99798 respectively. Mutation rates for STR loci did not exceed 1-4 per 1000 parent/child pairs as derived from disputed paternity cases. Similar mutation rates were also reported from other populations. No mutations were found for D5S818, D7S820, TH01, and TPOX.

Lymphocytic interstitial pneumonia (LIP) is an uncommon histopathologic entity characterized by infiltration of the interstitium and alveolar spaces of the lung by lymphocytes and other lymphoid elements. An increased incidence of LIP has been seen in the pediatric population, especially in children with acquired immune deficiency syndrome. Our previous study supports the notion that Langerhans cells (LCs) are reservoirs for Epstein-Barr virus (EBV) in lungs of human immunodeficiency virus (HIV) subtype E-infected pediatric LIP. To further understand the pathogenesis of LIP, we studied the relationship between EBV, the suggested causative agent of LIP and HIV-1 capsid protein p24, which play an important role in the interaction with host proteins during HIV-1 adsorption, membrane fusion, and entry in surgical lung biopsy-proven LIP from 9 vertically HIV subtype E-infected pediatric patients. The dominant microscopic feature of LIP demonstrated widespread widening of alveolar septum by mononuclear inflammatory cell infiltrate, mainly composed of mature lymphocytes and plasma cells surrounding airways and expanding to the lung interstitium. EBV-encoded RNA (EBER) in situ hybridization (ISH) and p24 immunohistochemistry, performed on formalin-fixed, paraffin-embedded tissue from open lung biopsy specimens, revealed positive intranuclear EBER signals and intracytoplasmic immunostains for p24 core protein in all 9 LIP cases. By combining ISH and immunohistochemistry, these results suggest that (i) EBV/p24-carrying cells are likely involved in the development of LIP, either directly or indirectly; (ii) LCs and related dendritic cells are the main reservoir of both EBV and HIV subtype E in pediatric LIP and possibly LCs may play an important role in the recruitment of inflammatory cell infiltrates, especially T cells into these tissues; (iii) coexpression of EBV/p24 in bronchioalveolar epithelium supports the hypothesis that these cells serve as a reactivation source for both viruses to achieve greater quantities in alveolar septum and interstitium around bronchioles. These results indicate a strong association between the presence of HIV core protein p24 and expression of EBV RNA transcripts (EBER). Interactions between LCs and related dendritic cells together with T cells are important for effective HIV and EBV replications. The coexpression of both viruses could be related to the evolution of pediatric LIP in HIV subtype E infection.

Aim of the study Gimjeng and Chakapat lychee (Litchi chinensis Sonn.) were evaluated for hepatoprotective activity on CCl4-induced hepatotoxicity in rats. Materials and methods Fruit pulp extracts of the lychees were examined for vitamin C, phenolic contents, anti-lipid peroxidation activity and hepatoprotective effect. Male Wistar albino rats were intraperitoneally injected (ip) with CCl4 (2 ml/kg), then were orally administered (po) with silymarin (100 mg/kg), and Gimjeng or Chakapat extracts (100 and 500 mg/kg). After ten days, the rats were sacrificed and their livers were examined histopathologically and immunohistochemically. Their serum glutamate–pyruvate transaminase, glutamate–oxalate transaminase, and alkaline phosphatase activities were analyzed. Apoptotic activity of the livers was assessed quantitatively. Results The Gimjeng and Chakapat extracts showed the contents of vitamin C (1.2 ± 0.6 and 4.3 ± 0.1 mg/100 g) and phenolics like trans-cinnamic acid and pelargonidin-3-O-glucoside (9.80 ± 0.21 and 19.56 ± 0.4 mg GAE/g extract, respectively), and trolox equivalent antioxidant capacity (TEAC) values (11.64 and 9.09 g/mg trolox), respectively. The Gimjeng as compared to the Chakapat demonstrated a better antioxidant activity as revealed by anti-lipid peroxidation activity with the TEAC values. Administration of CCl4 in rats elevated the serum GPT, GOT, and ALP level whereas silymarin, Gimjeng and Chakapat extracts prevented these increases significantly. Significant decrease of apoptotic cells together with restoration of morphological changes confirmed the hepatoprotective effect in the CCl4-induced rats pretreated with the extracts. Conclusion Antioxidant properties of the Gimjeng and Chakapat lychees as evidenced by the vitamin C and phenolic compounds, anti-lipid peroxidation and anti-apoptosis could explain the hepatoprotective effects in CCl4-induced hepatotoxicity.

To study the incidences and physical effects of sexually abused children and adolescents.Rape records and records of 250 sexually abused children and adolescents treated at Taksin Hospital between January 1, 1999 and December 31, 2004 from Child-Women Protection Center were studied retrospectively.The incidence of sexual abuse in children and adolescents was 4.74 per 10,000 cases of age-adjusted patients at the OPD and 22.97 at the emergency department. Most of the cases (97.20%) were females. Mean age was 13.74 +/- 4.27 (2-20) years old. Most of the cases were early adolescents (52.40%), late adolescents 32.40%, and children 15.20%. Thirty-nine cases (15.60%) had physical injuries, 36 cases (14.40%) had external genital injuries, 25 cases (10.00%) had gonococcal infections, 15 cases (6.20%) had bleeding in the vaginal canal, and eight cases (3.20%) were pregnant. Two hundred and twenty six cases (90.40%) were reported to the police. There was correlation between age group and hymen tearing (p-value0.001), gonococcal infection (p-value0.01) and sperm finding (p-value0.001). However there was no correlation between age group and gender, physical injury, genital injury, bleeding in the vagina and acid phosphatase finding. In addition, there was correlation between physical injury and bleeding in the vagina (p-value0.01) but no correlation between genital injury and hymen findings.Sexual abused victims need immediate attention for the traumatic impacts of their physical, psychological, and emotional conditions, as well as on their social impact. Thus, it is imperative that protection be exerted over the treatment to prevent recurrence.

The frequency and the cellular basis for HIV-1 transmission from mother to child in the early gestational period are poorly understood. We compared the placentas of 24 women seropositive for HIV-1 subtype E and who had not received any antiretroviral drugs, to placentas of 25 seronegative women. All placentas were obtained during therapeutic abortion at 6–23 weeks gestation. Placentas and fetal organs were examined by routine light microscopy, immunostaining for p24 capsid protein, and in situ PCR to localize which cells were infected with HIV-1 subtype E. The number of previous abortions was not a factor in placental HIV infection since this number was higher in seronegative women (P

We designed new primers that give shorter amplicons for Penta D and Penta E for easy separation on native polyacrylamide gels. 112 unrelated Northern Thai men were typed. A total of nine and eight-teen alleles was found for Penta D and Penta E, respectively. Both loci showed a high power of discrimination (Penta D: 0.927; Penta E: 0.966; both loci combined: 0.9975) as reported in other populations. Penta D met Hardy-Weinberg expectations, whereas Penta E did not, maybe because of the small sample size in relation to the large number of alleles of this locus.

The DIS80 and VWA loci were studied in a Karen population from Northern Thailand by the polymerase chain reaction and polyacrylamide gel electrophoresis. Twelve DIS80 and six VWA alleles were found. No deviations from the Hardy-Weinberg and linkage equilibrium were observed. The power of exclusion (PE) from the analysis of the DIS80 and VWA locus is 0.67 and 0.45, respectively, the power of discrimination (PD) is 0.95 and 0.85, respectively, with a combined PD of 0.99 and PE of 0.82.

We wish to thank Drs. Kreitchmann Canti Gomes da Silva Barcelos and Fuchs for their letter about our paper and for their interest and comments. We would like to take this opportunity to provide some additional information in response to their questions. The authors asked about whether there was a significant correlation between maternal viral load and HIV expression in placenta. In our series we did not find that there was a significant correlation. Whether this is related to small sample size or differences in subtype E behavior is unclear. We did find examination of the placenta to be informative with respect to HIV expression. We would recommend that this organ be examined in cases of HIV positive mothers for a better understanding of the pathogenesis of HIV transmission to fetuses and infants even if not for any intrinsic prognostic value. (excerpt)

The STR locus HUMTH01 was studied in 110 unrelated Thais from the area of Chiang Mai in North Thailand. By using PCR and vertical PAGE, six alleles were identified and the frequencies ranged from 0.005 to 0.400. The allele frequency distribution in this population showed significant differences from a Japanese population and other ethnic populations but was similiar to Asians in the USA and Australia. The genotype distribution meets Hardy-Weinberg expectations. The average power of exclusion (in no-parent and one-parent cases) and the discriminating power (DP) were calculated to be 0.3020, 0.4761 and 0.8722 respectively.

Department of Pathology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand; Department of Forensic Medicine Molecular Laboratory, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand; Department of Pathology, University of Southern California, CA, USA; Division of Pathology, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada

Primers currently used for amplification of locus DYS385 on the Y chromosome give quite long amplicons that are difficult to resolve on native polyacrylamide gels. We therefore designed new primers that give much shorter products for easy separation. With this system, two allele variants that were characterized by sequencing as 14.1 (GAAA --> GAAAA) and 14.2 (GA insertion), were identified in two unrelated Northern Thai men due to their decreased mobility. Interestingly, initial capillary electrophoresis mistyped the 14.1 variant amplified with the traditional primers as allele 14. Forty different haplotypes were found in 147 Northern Thais with a haplotype diversity of 0.9430. Haplotype 13-18 (frequency 0.136) is the most frequent one: for comparison: haplotype 14-18 (frequency 0.074) was found to be the most common in a population from Bangkok (n = 95) in an earlier study. This striking difference within Thailand's population probably results from genetic differences in the founding populations.

Zinc is present in high concentration in semen, but in low concentration in vaginal fluid. We evaluated vaginal zinc levels as a marker for intercourse by measuring precoital (greater than 11 h after intercourse) or postcoital (less than 5 h after intercourse) zinc and acid phosphatase levels in 26 specimens of vaginal fluid from 18 women. The approximate 95% reference range for zinc in precoital vaginal fluid was 1.2 to 15 micrograms/mL (mean 4.5), and in postcoital vaginal fluid 4.0 to 135 micrograms/mL (mean 24). There is an overlap between the precoital and postcoital reference ranges. Provided that the vaginal fluid zinc level is less than approximately 4.0 micrograms/mL or greater than approximately 15 micrograms/mL, vaginal fluid zinc concentration may be useful as an indicator of intercourse.