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PubMed1981

Huntington's Chorea in South Wales. A genetic and epidemiological study.

A study of Huntington's Chorea in South Wales has shown a prevalence of 7.61 per 100,000 in the counties of Gwent and Glamorgan, with a total population of 1.7 million. Heterozygote frequency is close to 1 in 5,000. Total ascertainment within this area has been attempted, and experience since conclusion of the study has shown no patients who have been omitted apart from those originating outside the area and those new cases with no living affected relatives. Analysis of migration patterns suggests that around 20% of cases in each generation arise from outside Glamorgan and Gwent and that around 12% of first-degree relatives of indigenous cases have left the area. The survey has formed the initial phase of a long-term prospective study of the disease involving systematic genetic counselling of all high-risk individuals and regular surveillance to monitor possible trends in future prevalence.

Genetic Counseling↗
PubMed1994

Molecular characterisation of an Italian G6PD variant responsible for chronic non-spherocytic haemolytic anaemia.

An Italian deficient G6PD variant associated with chronic non-spherocytic haemolytic anaemia (CNSHA) was biochemically characterised and studied at molecular level. Single-strand conformation polymorphism (SSCP) analysis led to the identification of an abnormal migration pattern of an amplified fragment encompassing exons 10 and 11 of the G6PD gene. Sequence analysis of both strands using an automated fluorescent DNA sequencer revealed a G-->A transition at nt. position 1246 in exon 10. A C-->T substitution at nt. 1311 in exon 11 was also found, which has already been described as a silent mutation common in Caucasians. The 1246 G-->A mutation has been described only in a Japanese subject with CNSHA (G6PD Tokyo) not associated with the 1311T polymorphism, suggesting that this mutation may have arisen independently in Europe and Asia.

Adult↗
PubMed1998

A 'de novo' point mutation of the low-density lipoprotein receptor gene in an Italian subject with primary hypercholesterolemia.

Severe hypercholesterolemia was found in an 11-year-old boy with no family history of familial hypercholesterolemia. The reduced LDL-receptor activity in cultured skin fibroblasts (40% 125I-LDL degradation as compared with a control cell line) indicated the presence of an LDL-receptor defect. The analysis of the promoter region and the exons of LDL-receptor gene by single strand conformation polymorphism revealed an abnormal migration pattern in exon 1, which was due to a T --> A transversion at nucleotide 28 of the cDNA. This novel mutation causes an arginine for tryptophane substitution at position - 12 of the signal peptide (W-12R) and introduces an AviII restriction site in exon 1. Screening of the mutation by polymerase chain reaction (PCR) amplification of exon 1 and AviII digestion revealed that none of the proband's family members carried the mutation. Non-paternity was excluded after the analysis of a battery of 14 short tandem repeats located in 13 different chromosomes. These results are consistent with the hypothesis that the proband is heterozygous for a 'de novo' mutation of the LDL-receptor gene producing a non-conservative amino acid substitution. We suggest that the change in the net charge of the signal peptide, caused by the addition of a positively charged amino acid, impairs the co-translational translocation of the nascent receptor protein across the endoplasmic reticulum membrane.

Adolescent↗
PubMed2006

HLA-A and HLA-B distribution in Toto - a vanishing sub-Himalayan tribe of India.

The frequency of HLA-A and HLA-B locus alleles was studied by using polymerase chain reaction-based sequence-specific primer method in a very primitive and vanishing sub-Himalayan Indian Tribe, the Toto population of North Bengal. The Toto, a Mongoloid tribe with a population size of 1172 reside only in the Totopara of Jalpaiguri district of North Bengal. We studied 40 individuals and observed some high frequency alleles when compared to other Indian tribal, non-tribal, and major world populations. Particularly, the frequency of HLA-B14 was 32.5% in the Toto population, the highest known frequency reported in any population in the world. This indigenous tribal population may harbour novel HLA alleles and unique haplotypes which extensive HLA genotyping will help to reveal, and thus further our understanding of their genetic admixture and migration patterns.

Alleles↗
PubMed1989

Chemical characterization and biologic properties of lipopolysaccharide from Bacteroides gingivalis strains W50, W83, and ATCC 33277.

The chemistry and selected biological activity of lipopolysaccharide (LPS) from Bacteroides gingivalis strains W50, W83, and ATCC 33277 were compared, as well as the role of this molecule as a mediator of selected inflammatory responses. Chemically, the LPSs consisted of 47-58% Lipid A, 5-10% carbohydrate, 0.05% 3-deoxy 2-octulosonic acid, 0.3% heptose, 3.8-5.2% hexosamine, and 2% phosphate. Rhamnose represented the dominant sugar (26-36%), with lesser amounts of glucose (18-34%), galactose (18-25%), mannose (9-12%), glucosamine (7-11%), and galactosamine (2-5%). The major fatty acids were: 13-methyl-tetradecanoate (42-45%), 3-OH-heptadecanoate (21-23%), hexadecanoate (16-19%), and 12-methyl-tetradecanoate (6-8%). SDS-PAGE and sodium deoxycholate-PAGE revealed the LPS to be a smooth chemotype. Differences in migration patterns between the virulent and avirulent strain LPSs also occurred. C3H/HeN macrophages (Mø) exposed to 1 microgram/ml of LPS released 3.2-4.2 ng of prostaglandin E (PGE)/ml of supernatant, representing 236-278% of control. Interleukin-1 (IL-1) activity in C3H/HeN and C3H/HeJ Mø exposed to 50 micrograms of LPS/ml was 382-724% and 270-300% of control, respectively; similar Mø exposed to 10 micrograms of LPS/ml released 1.6-2.0 ng and 0.3-0.5 ng of tumor necrosis factor (TNF)/ml of supernatant, respectively. Maximum TNF release in C3H/HeN Mø occurred in response to 50 micrograms of LPS/ml, and was sustained for up to 96 hours. These results suggest that LPS from the B. gingivalis strains stimulate cytokine production from Mø which, in turn, may play a role in orchestrating the inflammatory response for the development of periodontal diseases.

Bacterial Outer Membrane Proteins↗
PubMed1982

Purification of Drosophila acidic ribosomal proteins.

The relatively acidic proteins (group A80) of Drosophila melanogaster ribosomes were separated by ion-exchange chromatography. Fractions containing one or more acidic proteins were combined into thirteen pools. The criterion for the combination was the migration pattern in one-dimensional polyacrylamide gels containing sodium dodecyl sulphate. Five proteins (7/8, S25/S27, S14, L1/L2 and L5/L6) required no further purification. The others were further purified as follows: proteins S7, and S9 by preparative gel electrophoresis: and protein 13 (to newly identified protein) by adsorption with conconavalin-A--agarose. Four proteins had no detectable contamination, and in each of the others the impurities were no greater than 3%. The amount of purified protein recovered from a starting amount of 2.63 g total 80-S ribosomal protein and a starting amount of 105 mg group A80 varied from 0.4 mg to 8.8 mg. The molecular weight of the proteins was estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulphate. The amino acid composition of the individual purified proteins was determined. Several phosphorylated proteins were identified. Proteins 13b and 13c are phosphorylated derivatives of 13a; 7b/8b and 7c/8c are phosphorylated derivatives of 7a and/or 8a. Proteins 7/8 and 13 are distinct proteins but are very similar in amino acid composition.

Amino Acids↗
PubMed1996

Depolarization-induced tyrosine phosphorylation of paxillin in PC12h cells.

Treatment of PC12h cells with a high concentration of KC1 induces depolarization of the plasma membrane and Ca2+ influx into the cells. We have previously shown that KC1 induced tyrosine phosphorylation of cellular proteins of 120, 110, 68, 44 and 42 kDa. In the present study, we found that the 68-kDa protein is paxillin, a tyrosine kinase substrate associated with the actin cytoskeleton. A calcium ionophore, A23187, also induced tyrosine phosphorylation of the 68-kDa protein, while KC1 did not in the presence of EGTA or nifedipine, indicating that the effect of KC1 was due to the Ca2+ influx into the cells. Tyrosine phosphorylation of paxillin was also induced by nerve growth factor and epidermal growth factor, but its migration patterns on an SDS/polyacrylamide gel were different, that is, nerve growth factor and epidermal growth factor caused upward shifts of the bands, while KC1 did not. However, both forms could associate with Csk and Crk. The effect of KC1 was blocked by cytochalasin D, indicating that tyrosine phosphorylation required the integrity of actin filaments. These results suggest that tyrosine phosphorylation of paxillin may be involved in Ca2+ -dependent events in neuronal and neuroendocrine cells.

Animals↗
PubMed1995

Inflammation in the bovine teat cistern induced by Staphylococcus aureus.

The inflammatory response, characterized by the accumulation of leukocytes, bovine serum albumin and the lysosomal enzyme N-acetyl-beta-D-glucosaminidase, was studied after inoculation of either 5 x 10(5) colony-forming units (CFU) or 2 x 10(2) CFU of the Staphylococcus aureus strain SA 14391 into teat cisterns of dry cows after surgical closure of the passage between the teat and udder cisterns. Teat cistern samples were taken before, and twice daily for 7 days after, inoculation of the bacteria. Infusion of sterile saline constituted a control. Persistent infections occurred in all teats inoculated with the higher dose (5 x 10(5) CFU) of bacteria, and a prominent inflammatory response was elicited. Marked differences were observed in leukocyte migration patterns between different cows, and a cyclic influx of leukocytes was evident. Inoculation of the lower dose (2 x 10(2) CFU) of bacteria did not result in a persistent infection, and only a slight inflammatory response was observed. The results indicate that the bovine teat tissues are capable of mounting a strong local inflammatory response to S. aureus infection. A large number of leukocytes invaded the teat, but, despite their numbers, they were unable to subdue the infection, except when the bacterial count was low.

Acetylglucosaminidase↗
PubMed1993

Barriers to gene flow estimated by surname distribution in Italy.

Surname distributions were studied in order to reconstruct human migration patterns. Zones of sharp change in surname frequencies--presumably barriers to gene flow--were detected by the statistical technique of wombling (Barbujani et al. 1989), using data from consanguineous marriages (1910-64) collected from 280 Italian dioceses which we grouped into 80 provinces. The 28 observed surname boundaries were compared with physical (geographical) and cultural (linguistic) barriers, and with boundaries detected from distributions of 57 alleles in the same territorial subdivisions. Genetic and surname boundaries had similar locations, as expected given the analogy in the inheritance mechanism of genes and surnames. Physical barriers seemed to be the main cause of gene flow reduction. However, cultural factors alone (e.g. linguistic ones) also determined barriers that delimited areas of homogeneous gene (and surname) frequency probably due to increased endogamy. The observed similarity between spatial patterns of surnames, genes and languages supports the hypothesis of the co-evolution of genetic and linguistic variation.

Demography↗
PubMed2007

A bidirectional corridor in the Sahel-Sudan belt and the distinctive features of the Chad Basin populations: a history revealed by the mitochondrial DNA genome.

The Chad Basin was sparsely inhabited during the Stone Age, and its continual settlement began with the Holocene. The role played by Lake Chad in the history and migration patterns of Africa is still unclear. We studied the mitochondrial DNA (mtDNA) variability in 448 individuals from 12 ethnically and/or economically (agricultural/pastoral) different populations from Cameroon, Chad, Niger and Nigeria. The data indicate the importance of this region as a corridor connecting East and West Africa; however, this bidirectional flow of people in the Sahel-Sudan Belt did not erase features peculiar to the original Chad Basin populations. A new sub-clade, L3f2, is described, which together with L3e5 is most probably autochthonous in the Chad Basin. The phylogeography of these two sub-haplogroups seems to indicate prehistoric expansion events in the Chad Basin around 28,950 and 11,400 Y.B.P., respectively. The distribution of L3f2 is virtually restricted to the Chad Basin alone, and in particular to Chadic speaking populations, while L3e5 shows evidence for diffusion into North Africa at about 7,100 Y.B.P. The absence of L3f2 and L3e5 in African-Americans, and the limited number of L-haplotypes shared between the Chad Basin populations and African-Americans, indicate the low contribution of the Chad region to the Atlantic slave trade.

Chad↗
PubMed1991

Developmental expression of HNK-1-reactive antigens in rat cerebral cortex and molecular heterogeneity of sulfoglucuronylneolactotetraosylceramide in CNS versus PNS.

Monoclonal antibody HNK-1 reacts with a carbohydrate epitope present in proteins, proteoglycans, and sulfoglucuronylglycolipids (SGGLs). On high-performance TLC plates, SGGLs of the CNS from several species migrated consistently slower than those from the PNS, a result indicating possible differences in the structures. The structural characteristics of the major SGGL, sulfoglucuronylneolactotetraosylceramide (SGGL-1), from CNS was compared with those of SGGL-1 from PNS. Although the composition, sequence, and linkages of the carbohydrate moiety of the SGGL-1 species were identical, SGGL-1 from CNS contained mainly short-chain fatty acids, 16:0, 18:0, and 18:1, amounting to 85% of the total fatty acids, whereas SGGL-1 from PNS contained large proportions (59%) of long-chain fatty acids (greater than 18:0). These differences in the fatty acid composition accounted for the different migration pattern observed. The developmental expression of SGGLs and HNK-1-reactive proteins was studied in rat cerebral cortex between embryonic day (ED) 15 to adulthood. SGGLs in the rat cortex were maximally expressed around ED 19 and almost completely disappeared by postnatal day (PD) 20. This expression was contrary to their increasing expression in the cerebellum and sciatic nerve with postnatal development. Six to eight protein bands with a molecular mass of greater than 160 kDa were HNK-1 reactive in the rat cerebral cortex at different ages. The major HNK-1 reactivity to the 160-kDa protein band seen in ED 19 to PD 10 cortex decreased and completely disappeared from the adult cortex, whereas several other proteins remained HNK-1 reactive even in the adult. Western blot analyses of the neural cell adhesion molecules (N-CAMs) during development of the rat cortex with a polyclonal anti-N-CAM antibody showed that the major HNK-1-reactive protein bands were not N-CAMs. Between PD 1 and 10, 190-200-kDa N-CAM was the major N-CAM, and between PD 15 to adulthood, 180-kDa N-CAM was the only N-CAM present in the rat cortex.

Amino Acid Sequence↗
PubMed2006

Case report: the occurrence of fibrillary lines in overnight orthokeratology.

BACKGROUND: To report the occurrence of concentric fibrillary lines in the central corneas of a 13-year-old girl during overnight orthokeratology. METHODS: Observational case report. RESULTS: The initial refractive errors and keratometric readings (flattest/steepest meridians) of the patient were -6.00/-0.50 x 180 and 45.25/46.20 D, respectively, in the right eye and -5.50 DS and 44.90/45.80 D, respectively in the left eye. She underwent orthokeratology for myopic control, with a target reduction of 4.00 D myopia. A pair of DreimLens lenses was prescribed to be worn on a nightly basis and spectacles were worn by day. The same orthokeratology lenses were used throughout the monitoring period. Corneal topography showed well-centred treatment zones but persistent peripheral corneal staining due to trichiasis. A faint, peripheral pigmented brownish corneal arc and bundles of fine concentric fibrillary lines were observed in the central cornea about 12 months after commencing lens wear. In view of the persistent corneal staining due to trichiasis, she was advised to stop the orthokeratology treatment after 16 months of lens wear and was prescribed 1-Day Acuvue daily disposable contact lenses. The pigmented line disappeared after 2 months of hydrogel lens wear, while the fibrillary lines took 10 months to resolve. CONCLUSIONS: Fibrillary lines are a feature of the normal cornea thought to represent the arrangement of the subbasal, epithelial nerve plexus. We hypothesize that orthokeratology lens wear stimulates an altered epithelial migration pattern and a structural reorganisation of the subbasal nerve plexus in relation to this. This is assumed to account for the concentric pattern of fibrillary lines seen in our patient. The lines had no effect on vision and resolved over a period of 10 months following cessation of orthokeratology lens wear.

Adolescent↗
PubMed1995

Increased cell death and reduced neural crest cell numbers in ethanol-exposed embryos: partial basis for the fetal alcohol syndrome phenotype.

Fetal alcohol syndrome (FAS) is characterized by growth retardation, craniofacial malformations, and heart and neural defects; the cellular and molecular mechanism(s) responsible for ethanol's teratogenicity remains unknown. Although the phenotype suggests that prenatal ethanol exposure perturbs neural crest cell development, direct proof that these cells are an in utero target is still lacking. Previous research suggested that cranial neural crest cells are eliminated by ethanol-induced apoptosis. We tested this hypothesis using a chick embryo model of FAS. A single dose of ethanol, chosen to achieve a concentration of 35-42 mg/dl, was injected in ovo at gastrulation and resulted in growth retardation, craniofacial foreshortening, and disrupted hindbrain segmentation. Ethanol exposure enhanced cell death within areas populated by cranial neural crest cells, particularly in the hindbrain and craniofacial mesenchyme. In contrast, control embryos had limited cell death within these regions. Subsequent immunolabeling with neural crest cell-specific antibody revealed that ethanol treatment resulted in fewer neural crest cell numbers, whereas neural crest migration patterns were unaffected by ethanol. These results suggest that prenatal ethanol exposure leads to loss of cranial neural crest cells. Such a loss could result, in part, in the phenotype characteristic of FAS.

Animals↗
PubMed1984

Characterization of the antigen-specific T cell receptor from a pigeon cytochrome c-specific T cell hybrid.

The monoclonal antibody, A2B4-2, specifically bound to and inhibited antigen-induced IL-2 release from the cloned pigeon cytochrome c-specific T cell hybrid, 2B4. The initial immunoprecipitation with these reagents demonstrated a protein of 85-90kd on non-reducing conditions, and two bands of 45-50 and 40-44 on reducing conditions. These data enabled us to conclude that this monoclonal antibody bound to the antigen receptor on the 2B4 cell. In this paper we have presented results that further define the receptor structure. The migration pattern of the protein on SDS-PAGE in the presence and absence of reducing agents was consistent with the interpretation that the receptor has intrachain disulfide bonds that create globular domains. Sequence data from the recently described cDNA clones that encode receptor genes confirm that there are cysteine residues in positions that could be involved in such disulfide bonding. Since both alpha and beta chains behave identically on the SDS-PAGE we predict that both chains have the same double domain structure. The antigen receptor has a heterodimeric structure. A relatively simple acidic alpha chain is bound to one of two forms of the beta chain. Some of the receptors have a beta chain equal in molecular weight to the alpha chain, while some of the beta chains (beta') are heavier and more acidic. The difference in beta chain forms appears to be due to different levels of glycosylation of this chain. The cDNA sequence data demonstrate that there are several possible carbohydrate addition sites on the protein encoded by this gene so it may be that 2B4 beta chains are present that are either completely or partially glycosylated at these sites. Finally, we have presented a preliminary experiment that indicates that a smaller 20-25kd molecule is associated with the antigen receptor. The well characterized T3 molecule appears to be in a complex with the clonotypic structure on human T cells. The crosslinking data that we present suggests that a similar molecule may be present in the murine system.

Animals↗
PubMed1998

Effects of 13-cis-retinoic acid on hindbrain and craniofacial morphogenesis in long-tailed macaques (Macaca fascicularis).

Hindbrain and craniofacial development during early organogenesis was studied in normal and retinoic acid-exposed Macaca fascicularis embryos. 13-cis-retinoic acid impaired hindbrain segmentation as evidenced by compression of rhombomeres 1 to 5. Immunolocalization with the Hoxb-1 gene product along with quantitative measurements demonstrated that rhombomere 4 was particularly vulnerable to size reduction. Accompanying malformations of cranial neural crest cell migration patterns involved reduction and/or delay in pre- and post-otic placode crest cell populations that contribute to the pharyngeal arches and provide the developmental framework for the craniofacial region. The first and second pharyngeal arches were partially fused and the second arch was markedly reduced in size. The otocyst was delayed in development and shifted rostrolaterally relative to the hindbrain. These combined changes in the hindbrain, neural crest, and pharyngeal arches contribute to the craniofacial malformations observed in the retinoic acid malformation syndrome manifested in the macaque fetus.

Animals↗
PubMed2006

Lack of HIV seropositivity among a group of rural probationers: explanatory factors.

CONTEXT: Human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) in rural America has been described as an epidemic, and the HIV prevalence rate among criminal justice populations is higher than the general population. Thus, criminally involved populations in Southern rural areas are at elevated risk for contracting HIV because of drug and sexual practices; however, little is known about HIV/AIDS in the fastest growing criminal justice population-probationers. PURPOSE: To examine possible explanations for the lack of HIV seropositivity found in a purposive sample of rural probationers. METHODS: Data were examined from 800 felony probationers from 30 counties in Kentucky's Appalachian region. Measures included HIV prevalence within the 30 counties, migration patterns, HIV knowledge, substance use, and sexual risk behaviors. FINDINGS: These probationers had a high level of HIV knowledge, reported minimal injection drug use, practiced serial monogamy, and reported minimal engagement in transactional sex. However, these probationers also reported negligible condom use, and injection drug users shared needles and works. CONCLUSION: Findings suggest the importance of developing programs targeting safe sex practices in rural areas.

Adult↗
PubMed1999

No complementation between TP53 or RB-1 and v-src in astrocytomas of GFAP-v-src transgenic mice.

Human low-grade astrocytomas frequently recur and progress to states of higher malignancy. During tumor progression TP53 alterations are among the first genetic changes, while derangement of the p16/p14ARF/RB-1 system occurs later. To probe the pathogenetic significance of TP53 and RB-1 alterations, we introduced a v-src transgene driven by glial fibrillary acidic protein (GFAP) regulatory elements (which causes preneoplastic astrocytic lesions and stochastically astrocytomas of varying degrees of malignancy) into TP53+/- or RB-1+/- mice. Hemizygosity for TP53 or RB-1 did not increase the incidence or shorten the latency of astrocytic tumors in GFAP-v-src mice over a period of up to 76 weeks. Single strand conformation analysis of exons 5 to 8 of non-ablated TP53 alleles revealed altered migration patterns in only 3/16 tumors analyzed. Wild-type RB-1 alleles were retained in all RB-1+/-GFAP-v-src mice-derived astrocytic tumors analyzed, and pRb immunostaining revealed protein expression in all tumors. Conversely, the GFAP-v-src transgene did not influence the development of extraneural tumors related to TP53 or RB-1 hemizygosity. Therefore, the present study indicates that neither loss of RB-1 nor of TP53 confer a growth advantage in vivo to preneoplastic astrocytes expressing v-src, and suggests that RB-1 and TP53 belong to one single complementation group along with v-src in this transgenic model of astrocytoma development. The stochastic development of astrocytic tumors in GFAP-v-src, TP53+/- GFAP-v-src, and RB-1+/- GFAP-v-src transgenic mice indicates that additional hitherto unknown genetic lesions of astrocytes contribute to tumorigenesis, whose elucidation may prove important for our understanding of astrocytoma initiation and progression.

Animals↗
PubMed2003

Echo strength and density structure of Hawaiian mesopelagic boundary community patches.

A broadband sonar system and digital camera with strobe lights were mounted on a vertically profiling frame with a depth sensor. The echo strengths and densities of animals within individual mesopelagic boundary community patches were investigated as a function of depth. Time and distance from shore were also investigated. Simultaneous surface echosounder surveys permitted comparison of density estimates from two techniques. Echo strength values suggest nearshore boundary community animals are primarily myctophid fishes, which was confirmed by preliminary photographic evidence. Echo strength varied significantly as a function of distance from the shoreline and time. These measures of echo strength are important for estimating density from a surface echosounder. Density estimates from these revised echo strengths compare well with those made with echo highlight counting, which is independent of echo strength. These density measures suggest that previous density estimates were too low but do not change the conclusions of these studies. Vertical microstructure in density was apparent but animal size and compositional structure was not evident within a patch. Patch edges were abrupt, with no differences in the density or echo strength from patch interiors. These edges were generally straight, with a sharp drop in density to the background density of zero. Estimates of animal size as a function of time provide information about the diel migration patterns of these mesopelagic animals.

Journal Article↗