Sterilisation of Lucilia cuprina Wiedemann maggots used in therapy of intractable wounds

Three new techniques of sterilising maggots of Lucilia cuprina for the purpose of debriding intractable wounds were studied. These techniques were utilisation of ultra-violet C (UVC) and maggot sterilisation with disinfectants. The status of sterility was checked on nutrient agar and blood agar and confirmed with staining. The indicators for the effectiveness of the methods were sterility and survival rate of the eggs or larvae. Egg sterilisation with UVC had the lowest hatching rate (16+/-0.00%) while egg sterilisation with disinfectants showed high hatching rate (36.67+/-4.41%) but low maggot survival rate (31.67+/-1.67%). Sterilisation of the maggots was the most suitable, since the survival rate was the highest (88.67+/-0.88%). Complete sterility was achieved in all cases, except that Proteus mirabilis was consistently found. However, the presence of this microorganism was considered beneficial.

Helminth infections in small mammals from Ulu Gombak Forest Reserve and the risk to human health

A survey for small mammal parasites carried out in a secondary forest of Ulu Gombak, Selangor, Peninsula Malaysia yielded the following animals: Rattus bowersi (7), Rattus tiomanicus jalorensis (2), Maxomys rajah (12), Maxoyms whiteheadi (3), Leopoldamys sabanus(13), Sundamys muelleri(10), Lariscus insignis (1), Sundasciurus tenuis (1) and Tupaia glis (2). The following nematodes: Capillaria hepatica, Hepatojarakus malayae, Trichostrongylus sp. and Streptopharagus sp., the following cestodes: Hymenolepis sp., Raillietina sp. and Taenia taeniaformis; and trematode, Zonorchis sp. from Tupaia glis were recovered. No parasites were observed during blood examination. No endoparasite was seen in Maxomys whiteheadi, Lariscus insignis and Sundasciurus tenuis. The following parasites, Capillaria hepatica, Hymenolepis sp., Raillietina sp. and Taenia taeniaformis are considered of medical importance.

A newly identified HLA-C allele: Cw*1210, and confirmation of HLA-Cw*080102

HLA-Cw*1210 and -Cw*080102 were identified in Taiwan populations using reverse-line SSO typing method. Sequencing showed that HLA-Cw*1210 and -Cw*120201/02 were identical at exon 2 but differed at exon 3 with three nucleotide substitutions at codons 99 and 105 and an amino acid change from tyrosine to phenylalanine at codon 99. Also, allele HLA-Cw*080102 differed from HLA-Cw*080101 in exon 3 by a single synonymous nucleotide transition at codon 99. HLA-Cw*080102 was found only in the Puyuma indigenous tribe of Taiwan and had a frequency of 5%. Interestingly, nucleotide substitutions of HLA-Cw*1210 and -Cw*080102 were located in a noticeably heterogeneous region of the 5' end of exon 3, where similar substitution motifs are frequently found in other HLA-C alleles, therefore suggesting preferential gene conversion in this region.

Temperature related storage evaluation of an RT-PCR test kit for the detection of dengue infection in mosquitoes

The rapid detection of dengue infection in mosquito vectors is important for early warning to forestall an outbreak. Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) provides a rapid method for dengue detection in man and mosquitoes. An RT-PCR kit developed by the Medical Entomology Unit, Institute for Medical Research to detect dengue infection in mosquitoes, was tested for its shelf life at 3 storage temperatures: room temperature, refrigerator and freezer. Test kits were tested once every 3 days for kits stored at room temperature, and once every week for those stored at refrigerator and freezer temperatures. The results showed that the test kit could only be stored above its recommended storage temperature of -20 degrees C for not more than 3 days. DNA 100 bp markers in the kits appeared to be stable at the tested temperatures and were usable up to the 20th day when stored at 2 degrees C and below.

Determination of the flight range and dispersal of the house fly, Musca domestica (L.) using mark release recapture technique

In order to control any pest it is essential to study the life cycle, biology and bionomics of the target pest under control. With this respect, we have studied the flight range of the house fly Musca domestica (L.). The flight range of the house fly from two sites i.e, the poultry farm and a stable farm has been studied. The flight range study was conducted using a mark release technique. The approach we used in this study was that the flies collected from the respective farms were marked and released at different distances from the farms. The flies were then re-captured from the poultry farm and the stable farm. Studies conducted elsewhere use the technique of releasing the insect species at one spot and recapturing the insect species with the help of baited traps placed at various locations from the release point. The advantage of the approach used in this study was that the flight range as well as the homing effect was determined. From this study, the flight range of house flies released at the poultry farm was 7 km whereas flight range for flies release from stable farm was 5 km. The recovery rate of house flies at the poultry and stable farm was 0.05% and 0.016%, In this study, marked specimens has been detected up to 8 days in field conditions indicating that under field condition the life expectancy could be in the range of 1-2 weeks.

A fatal case of anaphylactic shock caused by the lesser banded hornet, Vespa affinis indosinensis in peninsular Malaysia

The hornets are a group of venomous stinging insects that at times cause human death. A fatal case of a child stung by the lesser banded hornet Vespa affinis indosinesis is reported. Though often covered by the mass media, this constitutes the first scientifically reported case.

Adult and larval insecticide susceptibility status of Culex quinquefasciatus (Say) mosquitoes in Kuala Lumpur Malaysia

The susceptibility of Culex quinquefasciatus to chemical insecticides in two field sites in Kuala Lumpur was evaluated using the WHO standard susceptibility test. Less then 7 days old female mosquitos, reared from wild caught females were exposed to discriminating dosages of insecticides at recommended exposure periods. The larval bioassay were conducted using the multiple concentrations and the LC50 value was determined. The results indicated that cyfluthrin is the most effective among all the insecticides tested with LT50 value of 29.95 min and 28.59 min, for the strain from Ampang Hill and Pantai Dalam, respectively. It was surprisingly to note that both these field strains showed 0% mortality when tested against malathion and DDT. The LC50 value indicated that both strains were highly resistant to malathion with resistance ratio of 17,988 folds and 14,053 folds, respectively. This concludes that resistance at larval stages is extremely high compared to adult stages.

Complete chloroplast genome sequences from Korean ginseng (Panax schinseng Nees) and comparative analysis of sequence evolution among 17 vascular plants

The nucleotide sequence of Korean ginseng (Panax schinseng Nees) chloroplast genome has been completed (AY582139). The circular double-stranded DNA, which consists of 156,318 bp, contains a pair of inverted repeat regions (IRa and IRb) with 26,071 bp each, which are separated by small and large single copy regions of 86,106 bp and 18,070 bp, respectively. The inverted repeat region is further extended into a large single copy region which includes the 5' parts of the rpsl9 gene. Four short inversions associated with short palindromic sequences that form stem-loop structures were also observed in the chloroplast genome of P. schinseng compared to that of Nicotiana tabacum. The genome content and the relative positions of 114 genes (75 peptide-encoding genes, 30 tRNA genes, 4 rRNA genes, and 5 conserved open reading frames [ycfs]), however, are identical with the chloroplast DNA of N. tabacum. Sixteen genes contain one intron while two genes have two introns. Of these introns, only one (trnL-UAA) belongs to the self-splicing group I; all remaining introns have the characteristics of six domains belonging to group II. Eighteen simple sequence repeats have been identified from the chloroplast genome of Korean ginseng. Several of these SSR loci show infra-specific variations. A detailed comparison of 17 known completed chloroplast genomes from the vascular plants allowed the identification of evolutionary modes of coding segments and intron sequences, as well as the evaluation of the phylogenetic utilities of chloroplast genes. Furthermore, through the detailed comparisons of several chloroplast genomes, evolutionary hotspots predominated by the inversion end points, indel mutation events, and high frequencies of base substitutions were identified. Large-sized indels were often associated with direct repeats at the end of the sequences facilitating intra-molecular recombination.

Widespread occurrence of small inversions in the chloroplast genomes of land plants

Large inversions are well characterized in the chloroplast genomes of land plants. In contrast, reports of small inversions are rare and involve limited plant groups. In this study, we report the widespread occurrence of small inversions ranging from 5 to 50 bp in fully and partially sequenced chloroplast genomes of both monocots and dicots. We found that small inversions were much more common than large inversions. The small inversions were scattered over the chloroplast genome including the IR, SSC, and LSC regions. Several small inversions were uncovered in chloroplast genomes even though they shared the same overall gene order. The majority of these small inversions were located within 100 bp downstream of the 3' ends of genes. All had inverted repeat sequences, ranging from 11 to 24 bp, at their ends. Such small inversions form stem-loop hairpin structures that usually have the function of stabilizing the corresponding mRNA molecules. Intra-molecular recombination between the inverted sequences in the stem-forming regions are responsible for generating flip-flop orientations of the loops. The presence of two different orientations of the stem-loop in the trnL-F noncoding region of a single species of Jasminum elegans suggests that a short inversion can be generated within a short period of time. Small inversions of non-coding sequences may influence sequence alignment and character interpretation in phylogeny reconstructions, as shown in nine species of Jasminum. Many small inversions may have been generated by parallel or back mutation events during chloroplast genome evolution. Our data indicate that caution is needed when using chloroplast non-coding sequences for phylogenetic analysis.

Review of forensically important entomological specimens in the period of 1972 - 2002

Forensic entomological specimens received by the Unit of Medical Entomology, IMR., from hospitals and the police in Malaysia in the last 3 decades (1972 - 2002) are reviewed. A total of 448 specimens were received. From these, 538 identifications were made with the following results: Eighteen species of cyclorrphaga flies were identified consisting of Chrysomya megacephala (Fabricius) 215 cases (47.99%), Ch. rufifacies (Masquart) 132 (29.46%), Ch. villeneuvi Patton 10 (2.23%), Ch. nigripes Aubertin 7 (1.56%), Ch. bezziana Villeneuve 4 (0.89%), Ch. pinguis (Walker) 1 (0.22%), Chrysomya sp. 47 (10.49%), Sarcophaga sp. 28 (6.25%), Lucilia sp. 21 (4.69%), Hermetia sp. 15 (3.35%), He. illucens (Linnaeus) 1 (0.22%), Hemipyrellia ligurriens (Wiedemann) 3 (0.67%), Hemipyrellia sp. 2 (0.45%), Ophyra spinigera 1 (0.22%), Ophyra sp. 6 (1.34%), Calliphora sp. 24 (5.36%), Synthesiomyia nudiseta (Wulp) 1 (0.22%) and Eristalis sp. 1 (0.22%). Other non - fly insect specimens are Pthirus pubis (Linnaeus) (Pubic louse) 2 (0.45%) and Coleoptera (Beetles) 1 (0.22%). Ch. megacephala and Ch. rufifacies were the commonest species found in cadavers from different ecological habitats. Sy. nudiseta is an uncommon species, thus far found only on cadavers from indoors. Sy. nudiseta is reported for the second time in Peninsular Malaysia. A total of 329 cases (73.44%) had a single fly infestation, 109 cases (24.33%) had double fly infestation and 10 cases (2.23%) had triple fly infestation. Five cases (1.12%) had eggs and 3 cases (0.67%) had larval stages that were not identifiable. No arthropods were retrieved from cadavers in 8 cases (1.79%). In conclusion, although large number of fly species were found on human cadavers, the predominant species are still those of Chrysomya.

Two novel HLA-DRB1 alleles identified using a sequence-based typing: HLA-DRB1*1443 and HLA-DRB1*1351*

Two novel HLA-DRB1 alleles, DRB1*1443 and DRB1*1351, were identified using a sequence-based typing protocol. DRB1*1443 differed from DRB1*140501 by one single-nucleotide substitution in exon-2 (codon 77, ACC-->GCC), which corresponded to an amino acid change of threonine to alanine. DRB1*1351 was identical to DRB1*1301 but differed by a single-nucleotide substitution at codon 50 (GTG-->TTG), resulting in an amino acid change of valine to leucine. Both new alleles present unique polymorphisms, which have not been seen among other DRB1 alleles and which have no known effect on peptide binding.

Space spraying of bacterial and chemical insecticides against Anopheles balabacensis Baisas for the control of malaria in Sabah, East Malaysia

A pilot study was undertaken to determine the effectiveness of space application of insecticides for the control of malaria in Ranau, a district in Sabah. A village each was treated monthly: with chemical adulticide--alpha cypermethrin (Fendona SC(R)/10SC(R)) at 2 g a.i./10,000 m2 in Pahu; with biological larvicides--Bacillus thuringiensis israelensis (Vectobac 12AS(R)) at 500 ml/10,000 m2 or B. sphaericus (Vectolex WG(R)) at 500 g/10,000 m2 in Pinawantai; and with a mixture of chemical adulticide and biological larvicide in Togop Laut. All sprayings were conducted using a portable mist blower. During the study period all villages, including Tarawas the untreated village, received the conventional malaria control measures. Entomological and epidemiological surveillance was used to measure the effectiveness of the space application. The entomological surveillance indicated that the An. balabacensis population was significantly reduced by alpha cypermethrin in Pahu and Togop Laut and B. sphaericus in Pinawantai; but was not reduced by B.t.i. in Pinawantai. There was a significant reduction in the number of malaria cases and in the slide positivity rate in the treated villages during the study period. The pilot study does indicate that space application of larvicides/adulticides or a mixture of both is able to reduce the malaria vector population and the malaria transmission. A larger scale study needs to be undertaken in a malarious village/province to determine whether space application of insecticides together with other malaria control measures will be able to eradicate malaria.

Identification of a new HLA-DRB1 allele, HLA-DRB1*0436

Anovel allele, HLA-DRB1*0436, was identified in a Taiwan indigenous individual by sequence-based typing. DRB1*0436 was identical to DRB1*0403 in exon2 but differed at codons 67-74 with five nucleotide substitutions. This corresponded to three amino acid changes within the P4 peptide-binding pocket of the DR molecule. These substitutions constitute a motif that is also seen in other DRB1*11 alleles. It is possible that the new allele resulted from a gene conversion event.

Properties of 137Cs in marine sediments off Yangnam, Korea

Concentrations of 137Cs in sediment and seawater samples in the East Sea (Japan Sea) adjacent to Yangnam, Korea were measured and data on the physical and chemical properties of the sediments were collected. The concentrations of 137Cs in the sediment samples were in the range of less than the minimum detectable activity (MDA)-7.19 Bq/kg-dry, and the values were linearly correlated with particle size, total organic carbon (TOC), H, N or S content of the sediment. The 137Cs concentrations in the sediment samples were well fitted to a multiple regression equation with TOC contents and particle size distributions. The distribution coefficients, which indicate the degree of adsorption, of 137Cs to the sediments were strongly dependent on particle size and TOC content.

hMLH1 and hMSH2 mutations in families with familial clustering of gastric cancer and hereditary non-polyposis colorectal cancer

The pattern of hMLHI and hMSH2 mutations was assessed to identify the genetic correlation between hereditary gastric and colorectal cancers. Four disease groups and their healthy family members were assembled according to the presentation of gastric cancer: FG, familial clustering of gastric cancer (n = 32); CG, family with one or more colorectal and gastric cancers in first-degree relatives (n = 22); HS, seven HNPCC families corresponding to the Amsterdam criteria (AMS+) and 12 suspected HNPCC families which did not satisfy one of the criteria (AMS-), but no gastric cancer among first- and second-degree relatives (n = 19); and SG, sporadic gastric cancer (n = 33). In the CG group, three were included in AMS + and six in AMS- criteria. Peripheral blood was obtained from them to detect hMLHI and hMLH2 mutations using PCR-SSCP analysis and direct sequencing. The incidence of mutations was 9.4% in the FG group, 54.5% in the CG group, 31.6% in the HS group, and none in the SG group. The incidence, type, and number of the mutation were not different between the CG and HS groups. Thirty-four different mutations included 19 in hMLH1 and 15 in hMSH2. Gastric cancer was the most common extracolonic malignancy in HNPCC and suspected HNPCC families (9/28, 32.1%). The hMLH1 or hMSH2 mutation occurred in seven of 10 families with AMS+, whereas it occurred in four of 18 with AMS- (70% vs. 22.2%, P = .013). Five mutations in the hMLH1 and six mutations in the hMSH2 were exclusively found in families with gastric cancer. All three mutations in the FG group were in hMLHI and there was no mutation in their healthy family members. This study demonstrates that some familial clustering type of gastric cancer appears to be associated with hMLHI mutations thereby indicating a difference from the hereditary gastric cancer studies previously reported. In addition, hMLHI and hMSH2 mutations may impact the gastric cancer carcinogenesis in HNPCC or suspected HNPCC.

Modeling fish community dynamics in the Florida Everglades: role of temperature variation

Temperature variation is an important factor in Everglade wetlands ecology. A temperature fluctuation from 17 degrees C to 32 degrees C recorded in the Everglades may have significant impact on fish dynamics. The short life cycles of some of Everglade fishes has rendered this temperature variation to have even more impacts on the ecosystem. Fish population dynamic models, which do not explicitly consider seasonal oscillations in temperature, may fail to describe the details of such a population. Hence, a model for fish in freshwater marshes of the Florida Everglades that explicitly incorporates seasonal temperature variations is developed. The model's main objective is to assess the temporal pattern of fish population and densities through time subject to temperature variations. Fish population is divided into 2 functional groups (FGs) consisting of small fishes; each group is subdivided into 5-day age classes during their life cycles. Many governing sub-modules are set directly or indirectly to be temperature dependent. Growth, fecundity, prey availability, consumption rates and mortality are examples. Several mortality sub-modules are introduced in the model, of which starvation mortality is set to be proportional to the ratio of prey needed to prey available at that particular time step. As part of the calibration process, the model is run for 50 years to ensure that fish densities do not go to extinction, while the simulation period is about 8 years. The model shows that the temperature dependent starvation mortality is an important factor that influences fish population densities. It also shows high fish population densities at some temperature ranges when this consumption need is minimum. Several sensitivity analyses involving variations in temperature terms, food resources and water levels are conducted to ascertain the relative importance of temperature dependence terms.

The use of genotyping to predict the phenotypes of human platelet antigens 1 through 5 and of neutrophil antigens in Taiwan

BACKGROUND

The human platelet antigen (HPA) 1 through 5 and the human neutrophil antigen (HNA-1) systems are relevant to immune-related thrombocytopenia and neutropenia. The alloantigen distribution profiles in the population will aid in estimating the risk of alloimmunization.

STUDY DESIGN AND METHODS

Genotyping of the genes that control the expression of the HPA-1 through -5 and HNA-1 systems in Taiwanese (n = 326) and Taiwan's indigenous peoples (n = 608) was performed by PCR with the sequence-specific primer (PCR-SSP) method.

RESULTS

In the HPA system, HPA-1b and HPA-4b were absent among Taiwan's indigenous tribes and detected among other Taiwanese only with frequencies of <0.2 percent and <0.5 percent, respectively. The GP1BA*2 (HPA-2b) and GP1A*2 (HPA-5b) allele frequencies range from 1 percent to 7 percent and 0.4 percent to 3.5 percent among the two ethnic groups, respectively. GP2B*1 (HPA-3a) and GP2B*2 (HPA-3b) showed similar allele frequencies. In the HNA-1 system, the FCGR3B*1 (HNA-1a) allele frequency was about twice that of FCGR3B*2 (HNA-1b) in Taiwanese and also in most of the indigenous tribes. Three FCGR3B (HNA-1) null persons were found in one indigenous tribe (Ami tribe), for an FCGR3B null frequency of 19.8 percent. However, no FCGR3B*3 (HNA-1c) allele was detected in Taiwan.

CONCLUSION

The frequencies of HPA-1b, -2b, and -5b in the Taiwanese population were much lower than those among whites. In Taiwan, all of the HNA-1 null found was due to the deletion of the FCGR3B gene, and this deletion may be widely distributed in the Ami tribe.

Polymorphism and distribution of the Secretor alpha(1,2)-fucosyltransferase gene in various Taiwanese populations

BACKGROUND

The Secretor gene (Se or FUT2), which produces alpha(1,2)-fucosyltransferase, exhibits extensive polymorphism. Six Se genes, including the weak Se (Se(w) or Se385) and three nonsecretor alleles (se571, se685, and se849) have been detected in various populations of Taiwan. The distribution of various Lewis phenotypes among the Taiwanese population groups has been shown to vary considerably.

STUDY DESIGN AND METHODS

A PCR-RFLP analysis system, which was based on the nucleotide polymorphism variation of the different Se alleles and which can reveal the Se genotype of an individual easily and accurately, was developed. The distribution of the Se alleles among Taiwanese population groups, including the two major populations, Minnan and Hakka Taiwanese, and 11 indigenous groups, was analyzed by the method.

RESULTS

Frequencies of the Se alleles among the Taiwanese populations were revealed. The distribution of the nonsecretor alleles, especially se849, showed a marked variation. A good correlation was observed between a person's Se genotype and Lewis phenotype.

CONCLUSION

The Se genes have a polymorphic distribution among various Taiwanese populations, and this agrees with previous results for Lewis phenotype distributions. The Se(w) allele and the three se alleles are responsible for the Le(a+b+) and Le(a+b-) phenotypes, respectively.

Inadvertent hypothermia causes pulseless electrical activity in a patient during cervical spine surgery--a case report

Recent studies have shown that hypothermia triples the incidence of major cardiac events. We present a happening in which a 71-year-old patient developed pulseless electrical activity (PEA) while he was undergoing cervical laminectomy for spinal stenosis in the sitting position. Thromboembolism or venous air embolism and acute myocardial infarction were respectively excluded by transesophageal echocardiography and cardiac enzymes analysis to be the causes of the cardiac event. The abnormal finding that stood out was low nasopharyngeal temperature (31 degrees C) during the procedure, which was thought to contribute to the development of the PEA episode.

Histone H1 phosphorylation by Cdk2 selectively modulates mouse mammary tumor virus transcription through chromatin remodeling

Transcriptional activation of the mouse mammary tumor virus (MMTV) promoter by ligand-bound glucocorticoid receptor (GR) is transient. Previously, we demonstrated that prolonged hormone exposure results in displacement of the transcription factor nuclear factor 1 (NF1) and the basal transcription complex from the promoter, the dephosphorylation of histone H1, and the establishment of a repressive chromatin structure. We have explored the mechanistic link between histone H1 dephosphorylation and silencing of the MMTV promoter by describing the putative kinase responsible for H1 phosphorylation. Both in vitro kinase assays and in vivo protein expression studies suggest that in hormone-treated cells the ability of cdk2 to phosphorylate histone H1 is decreased and the cdk2 inhibitory p21 protein level is increased. To address the role of cdk2 and histone H1 dephosphorylation in the silencing of the MMTV promoter, we used potent cdk2 inhibitors, Roscovitine and CVT-313, to generate an MMTV promoter which is associated predominantly with the dephosphorylated form of histone H1. Both Roscovitine and CVT-313 block phosphorylation of histone H1 and, under these conditions, the GR is unable to remodel chromatin, recruit transcription factors to the promoter, or stimulate MMTV mRNA accumulation. These results suggest a model where cdk2-directed histone H1 phosphorylation is a necessary condition to permit GR-mediated chromatin remodeling and activation of the MMTV promoter in vivo.

Relative language proficiency modulates BOLD signal change when bilinguals perform semantic judgments. Blood oxygen level dependent

The effect of relative language proficiency on the spatial distribution and magnitude of BOLD signal change was evaluated by studying two groups of right-handed English-Mandarin bilingual participants with contrasting language proficiencies as they made semantic judgments with words and characters. Greater language proficiency corresponded to shorter response times and greater accuracy in the semantic judgment task. Within the left prefrontal and parietal regions, the change in BOLD signal was smaller in a participant's more proficient language. The least proficient performance was associated with right, in addition to left, inferior frontal activation. The results highlight the importance of taking into consideration nature of task and relative language proficiency when drawing inferences from functional imaging studies of bilinguals.

Diversity of HLA among Taiwan's indigenous tribes and the Ivatans in the Philippines

Taiwan's indigenous tribes, especially the east coast tribes are not only closely related to Oceania but also with the Australian aborigines. The Ivatans of the Batan Islands in the Philippines are closely related to the Yami tribe of Taiwan as cultural and anthropological studies have shown. Many DRB1 alleles (*15021, *16021, *0404, *04051, *11011, *12021, *1401, *08032) have high allele frequencies (>20%) in certain tribes, suggesting Taiwan's indigenous tribes are homogeneous populations. These high frequency DRB1 alleles and also some HLA-A-B-DR haplotypes found in Taiwan's indigenous tribes are also found in Oceania, Australian aborigines, south and north east Asians and American Indians, lending further support to our previous findings that Taiwan's indigenous tribes are more or less genetically related to both northern and southern Asians, possibly as well as Amerindians. HLA-A*2402 with a remarkably high frequency among Taiwan's indigenous tribes (52.1% approximately 86.3%), especially the central mountain tribes, possibly represents not only founder effects and population bottlenecks, but also positive selection of the allele. Although the Ami tribe has the highest ever reported frequencies of the DRB1*0404 and DRB1*0405, these alleles have not been found to be associated with rheumatoid arthritis as previously described for Caucasians. In addition, DRB1*1401 has a high frequency in most tribes but is not associated with psoriasis as previously indicated in some studies, suggesting the involvement of some additional genetic and/or environmental factors mechanism in the development of these diseases.