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PubMed1991

Phlebotomus guggisbergi (Diptera: Psychodidae), a vector of Leishmania tropica in Kenya.

Sand flies were collected in light traps and on oiled papers at four active case sites of human cutaneous leishmaniasis due to Leishmania tropica at Muruku Sublocation, Laikipia District, Kenya. Nearly 5,200 females of five species, including Phlebotomus guggisbergi, were dissected and examined for flagellates. Of 3,867 P. guggisbergi females collected at a multiple case site, 168 (4.3%) harbored mature infections (to include metacyclic promastigotes) of flagellates morphologically identical to Leishmania, while all other flies were negative. Of the infected flies, 164 were collected in a cave near the patients' home, three from crevices on an escarpment immediately behind the house, and one from the bedroom of one of the patients. One hundred sixty-four of the isolates were successfully grown in Schneider's Drosophila medium and harvested for typing by cellulose-acetate electrophoresis. Isoenzyme profiles of the first 22 of these were compared with those of WHO reference strains and well characterized local strains using 12 enzyme loci. The isolates yielded isoenzyme migration patterns that were indistinguishable from those of two L. tropica reference strains and of six L. tropica patient isolates from the same locality. This is the first reported isolation of L. tropica from a sand fly in Kenya, the first reported isolation of Leishmania parasites from P. guggisbergi, and the first confirmed isolation of this Leishmania from a sand fly other than P. sergenti. The finding of such a large number of P. guggisbergi naturally harboring mature infections of L. tropica at an active case site of cutaneous leishmaniasis due to this agent strongly implicates this fly as a vector.

Animals↗
PubMed1978

[Molecular weight of lipovitellins during egg development in the crustacean amphipod Orchestia gammarella (Pallas)].

Egg lipovitellins of Orchestia gammarella tested by electrophoresis on gels of different acrylamide concentrations, following the procedure of Hedrick and Smith (1968), display a migration pattern identical to that of proteins with molecular weights of congruent to 3.2 x 10(5) (lipovitellin I) and congruent to 5.5 x 10(5) (lipovitellin II) respectively. Since their molecular weight remains constant during embryogenesis, the changes of their relative mobility in disc gels indicates alterations in their ionic charges.

Animals↗
PubMedDate not supplied

Lack of Fas and Fas-L mutations in patients with lymphoproliferative disorders associated with Sjögren's syndrome and type II mixed cryoglobulinemia.

OBJECTIVE: Murine models (MRL/gld/gld mice) and recent evidence in humans suggest a possible role of Fas and Fas ligand (Fas-L) germline mutations in the pathogenesis of autoimmune-related lymphoproliferation, including adult cases. In this study, the presence of Fas and Fas-L germline mutations was investigated in a consecutive series of adult patients with lymphoproliferative disorders occurring in the context of Sjögren's syndrome (SS) and type II mixed cryoglobulinemia (MC). METHODS: 11 patients (8 primary SS and 3 type II MC; F/M: 10/1; mean age 64 yrs.) were investigated. All patients were suffering from atypical lymphoproliferative disorders or MALT lymphoproliferative lesions (mean duration 3.5 yrs.). Four patients later developed a malignant lymphoma. DNA from peripheral blood mononuclear cells from 11 patients and 10 controls was tested for germline mutations in the Fas gene (exons 4, 8 and 9) and Fas-L gene (exon 4) by the polymerase chain reaction-single strand conformation polymorphism (SSCP) method. RESULTS: All DNA samples from both patients and controls showed amplification of Fas and Fas-L specific fragments. Identical SSCP migration patterns were observed in all the cases, indicating the lack of mutations in the whole series. CONCLUSION: Although it cannot be excluded that Fas and Fas-L mutations might be present in exons different from those analyzed, our data do not support the hypothesis that germline mutations in these genes are responsible for a major subset of lymphoproliferative syndromes in adult patients with SS and type II MC. Additional studies would be worthwhile in SLE-related lymphoproliferation, which is, however, a subset of limited clinical relevance when considering all cases with autoimmune-related lymphoproliferation.

Aged↗
PubMed1999

Biochemical and molecular genetic characteristics of the severe form of tyrosine hydroxylase deficiency.

BACKGROUND: Tyrosine hydroxylase (TH) catalyzes the rate-limiting step in the biosynthesis of the catecholamines dopamine, norepinephrine, and epinephrine. Recently, mutations were identified in cases of autosomal recessive dopa-responsive dystonia and infantile parkinsonism. We describe a patient with severe symptoms and a new missense mutation in TH. METHODS: Relevant metabolites in urine and cerebrospinal fluid were measured by HPLC with fluorometric and electrochemical detection. All exons of the TH gene were amplified by PCR and subjected to single-strand conformation polymorphism analysis. Amplimers displaying aberrant migration patterns were analyzed by DNA sequence analysis. RESULTS: The patient presented with severe axial hypotonia, hypokinesia, reduced facial mimicry, ptosis, and oculogyric crises from infancy. The major metabolite of dopamine, homovanillic acid, was undetectable in the patient's cerebrospinal fluid. A low dose of L-dopa produced substantial biochemical but limited clinical improvement. DNA sequencing revealed a homozygous 1076G-->T missense mutation in exon 10 of the TH gene. The mutation was confirmed with restriction enzyme analysis. It was not present in 100 control alleles. Secondary structure prediction based on Chou-Fasman calculations showed an abnormal secondary structure of the mutant protein. CONCLUSIONS: We describe a new missense mutation (1076G-->T, C359F) in the TH gene. The transversion is present in all known splice variants of the enzyme. It produces more severe clinical and biochemical manifestations than previously described in TH-deficient cases. Our findings extend the clinical and the biochemical phenotype of genetically demonstrated TH deficiency.

Amino Acid Sequence↗
PubMed2000

The lack of Emx2 causes impairment of Reelin signaling and defects of neuronal migration in the developing cerebral cortex.

Neocorticogenesis in mice homozygous for an Emx2 null allele is the topic of this article. The development of both main components of neocortex, primordial plexiform layer derivatives and cortical plate, was analyzed, paying special attention to radial migration of neurons forming the cortical plate. The products of the Reelin gene, normally playing a key role in orchestrating radial migration of these neurons, display normal distribution at the beginning of the cortical neuronogenesis but are absent in the neocortical marginal zone of the mutant mice at the time when the cortical plate is laid down. As a consequence, the development of radial glia is impaired, and neurons making up the cortical plate display abnormal migration patterns. In addition, restricted defects along the rostrocaudal and the mediolateral axes are present in the subplate, suggesting an Emx2-specific role in priming the proper development of this layer.

Animals↗
PubMed1975

Cellular cooperation during in vivo anti-hapten antibody responses. II. The effect of in vivo and in vitro x-irradiation on T and B cells.

The effect of x-irradiation on T and B cells involved in an in vivo adoptive anti-hapten antibody response has been studied. In vitro x-irradiation inactivates both B cells and T cells. B cells are somewhat more sensitive than T cells to such treatment, the dose required to reduce B cell activity by 50% being about 50 R, whereas 200 R will reduce helper cell activity by 50%. By contrast, if recipient mice are primed with carrier, they develop helper activity that is totally resistant to 500 R x-irradiation within 3 days of immunization. This activity can not be transferred from irradiated, carrier-primed mice by either spleen cells or serum, although anti-carrier antibody is shown to give a modest helper effect late after boosting. However, this radioresistant helper effect can be reproduced in a cell transfer system by giving carrier-primed spleen cells to normal recipients that are then x-irradiated (500R) and given a large dose of carrier protein. Neither cells nor carrier alone will give rise to such radioresistant helper effects. Similar helper activity is occasionally observed when normal mice are irradiated 24 hr after being given helper cells, in the abscence of carrier and boosted shortly thereafter. The differences between these radioresistant helper effects, and the radiosensitivity of helper cells transferred after x-irradiation, may be related to x-ray induced changes in cell migration patterns.

Animals↗
PubMed2000

West Nile virus activity--New York and New Jersey, 2000.

In late August 1999, an outbreak of encephalitis caused by West Nile virus (WNV) was detected in New York City and subsequently identified in neighboring counties (1). In response, an extensive mosquito-control and risk-reduction campaign was initiated, including aerial and ground applications of mosquito adulticides throughout the affected areas. No human WNV infections were found in New York City with an onset date after the campaign was completed. Cases continued to occur among humans in surrounding counties that did not undertake mosquito-control efforts until later, suggesting that the campaign may have reduced human risk. In May 2000, CDC issued guidelines to direct national surveillance, prevention, and control efforts (2) and provided funds to support these efforts in 19 state and local health departments where WNV transmission had occurred or where transmission would probably occur based on known bird migration patterns. This report presents the findings of surveillance activities.

Animals↗
PubMed2000

Distribution of patients with Wilson disease carrying the H1069Q mutation in Austria.

BACKGROUND/AIMS: More than 100 different mutations of the Wilson disease (WD) gene have been reported so far, but only the H1069Q mutation is frequently found in patients of North and East European origin. We wanted to know if there is a connection between the migration pattern in Central Europe and the geographical distribution of this mutation in Austria. METHODS: One hundred and nine patients (91 index patients and 18 asymptomatic siblings) with WD diagnosed in Austria were included in this study. Eighty-one of the 91 index patients were born in Austria. Evaluation criteria included the place of birth of each member of the study group, as well as of his parents and grandparents. RESULTS: Out of the 81 index patients born in Austria, 72 were tested for the H1069Q mutation. Twelve (16.7%) were homozygous carriers of the H1069Q mutation, 29 (40.3%) were compound heterozygous and 31 (43.0%) had an unknown mutation on both chromosomes. Eight of the twelve H1069Q homozygotes were born close to the northeastern border of Austria (neighboring the Czech Republic, Slovakia and Hungary). Compound heterozygous patients showed a more variable geographical distribution with respect to their birthplace. The patients with unknown mutation were scattered all over Austria. CONCLUSION: These data provide further evidence that the H1069Q mutation originates from Eastern Europe. In patients from these countries the PCR-based testing for this mutation may be useful for differential diagnosis and family studies.

Amino Acid Substitution↗
PubMed2000

International health and emerging infectious diseases.

This article explored the role of international health in reducing the impact of infectious diseases by espousing the monumental application of global electronic communication and socioeconomic development initiatives. The interaction between the society and environmental changes have dramatic effects on the frequency of infectious diseases worldwide. Development of dams, human population expansion, migration patterns, urbanization and the invasion of hitherto virgin forests, and global warming enhance the proliferation of vectors of infectious diseases. Sustainable development and emphasis on primary prevention initiatives, coupled with the application of technology to improve farming, provision of safe water and electrification of rural communities, are significant steps in infectious disease control.

Attitude to Health↗
PubMed2001

[Regional differences and Hantavirus pulmonary syndrome].

Factors related to the characteristics of Hantavirus pulmonary syndrome in Argentina are described. Factors from different scientific fields converge to form the syndrome's analytical framework. Some of these factors are the history of spatial occupation, work and production structures, human migration patterns, ethnic composition, reservoir dynamics and its relationship to the different circulating viruses, and human behavior. Furthermore, the multiple factors are expressed in three ecological frameworks, associated with three different geographical regions of Argentina: 1) Northwest; 2) Central ("wet Pampa"); and 3) South Andean. In order to understand the actual causality of health or disease as an interaction of many factors, research on the primary biological, social, and environmental determinants of diseases should attend to the complexity of variable relationships in each region. The multiple-factor convergence approach allows for the design of appropriate strategies to improve the population's health status. Therefore, strategies should be developed and transferred by multidisciplinary teams, while their sustainability should be assured by community participation beginning with the earliest steps of research onward.

Animals↗
PubMed2001

Microsatellite allele sizing: difference between automated capillary electrophoresis and manual technique.

By comparing data collected with different automated sequencers and a manual technique (fragment separation in a silver-stained polyacrylamide gel), we found strong discrepancies in allele size of microsatellite loci. To quantify the sizing bias generated by automated capillary electrophoresis, we typed 51 alleles at seven loci andfound that differences between actual (manual) and called (automated) sizing were inversely related to locus size. This result seems independent of the fluorescent dye but might be due to different migration patterns of the size standard and the microsatellite loci. Thus, it is essential to distinguish between actual (that can only be confirmed by sequencing) and called (obtained with automated sequencer) allele sizes. To enable the comparison of data collected by different laboratories on different instruments, the greatest attention should be paid to material and protocol descriptions used for allele sizing, and reference standard DNA genotypes should be shared between collaborating laboratories. Without these precautions, scoring errors in allele size might result in important misleading conclusions.

Alleles↗
PubMed2001

Fusion hybrids with macrophage and melanoma cells up-regulate N-acetylglucosaminyltransferase V, beta1-6 branching, and metastasis.

It was shown previously that a majority of hybrids produced by in vitro fusion of normal macrophages with Cloudman S91 melanoma cells displayed enhanced metastatic potential in vivo, increased motility in vitro, increased ability to produce melanin, and responsiveness to melanocyte stimulating hormone compared with the parental Cloudman S91 melanoma cells. These hybrids also showed altered N-glycosylation consistent with a slower migration pattern of lysosome-associated membrane protein (LAMP-1) on electrophoretic gels. Because LAMP-1 is the major carrier of polylactosamine sugar structures, and synthesis of this complex sugar moiety indicates the extent of beta1,6 branch formation by beta1,6-N-acetyl-glucosaminyltransferase V (GnT-V), we analyzed the expression of GnT-V and beta1,6 branching in highly metastatic macrophage-fusion hybrids and compared with poorly metastatic ones. GnT-V was up-regulated in regard to both mRNA levels and enzymatic activity specifically in metastatic hybrids as well as parental macrophages compared with weakly metastatic hybrids and parental melanoma cells. Macrophages and metastatic hybrids also showed increased binding of the lectin L-phytohemagglutinin, which specifically binds to the beta1,6-branched sugar moiety. In addition, in metastatic hybrids there was increased cell surface expression of LAMP-1 and beta1 integrin, two prominent substrates for GnT-V also known to be associated with metastasis. Finally, exposure of metastatic hybrids in vitro to L-phytohemagglutinin or LAMP-1 completely eliminated melanocyte stimulating hormone/ isobutylmethyl xanthine-induced motility, suggesting a role for GnT-V in the motility of these cells. In summary, macrophage fusion with melanoma cells often increased metastatic potential, which was associated with enhanced expression of GnT-V and beta1,6-branching in glycoproteins. It is suggested that the known correlation with elevated GnT-V in both human and animal metastasis could, at least in some cases, reflect previous fusion of tumor cells with tumor-infiltrating macrophages, which, similar to malignant cells, show elevated expression of GnT-V and beta1,6-branched polylactosamines.

Animals↗
PubMed2002

Detection of gsp somatic mutation through direct sequencing of heteroduplex alleles disclosed by denaturing gradient gel electrophoresis.

BACKGROUND: The identification of somatic mutations in tissues is often difficult when the number of normal alleles in the tissue far exceeds the number of mutant ones. We found that the identification of gsp mutation was not possible by direct sequencing and present a new approach that improves the identification of gsp somatic mutations. MATERIAL/METHODS: Genomic DNA was extracted from frozen tissue of a human ovarian stromal Leydig cell tumor. Exons 8 and 9 of the Gsa gene were amplified by PCR and despite the abnormal migration pattern at this first DGGE, direct sequencing of the PCR product did not reveal mutations, probably due to the small amount of mutant alleles. To improve this amount, the PCR products were re-amplified using as template the excised products of the mutant homoduplex and heteroduplex bands obtained at the first DGGE. RESULTS: This approach resulted in the enhancing of the mutant homoduplex bands whereas the heteroduplex bands remained unchanged at the second DGGE. Direct sequencing of the second round PCR clearly identified the mutation R201C in the ovarian Leydig cell tumor. CONCLUSIONS: We have demonstrated a relatively rapid, convenient and reliable method to improve gsp somatic mutation detection combining a second DGGE of the PCR products obtained from the heteroduplexes and mutant homoduplex bands disclosed in a first DGGE followed by direct sequencing.

Alleles↗
PubMed1975

Mesenchymal derivatives of the neural crest: analysis of chimaeric quail and chick embryos.

Interspecific grafts of neural tube and associated neural crest (NC) have been made between quail and chick embryos. Structural differences of the interphase nucleus in the two species make it possible to identify quail from chick cells in the chimaeras after Feulgen-Rossenbeck's staining and at the electron microscope level. Owing to the stability of the natural quail nuclear maker labelling, migration pattern and developmental fate of the grafted NC cells could be followed in the host embryo. In previous work it has been demonstrated that the visceral skeleton derives entirely from NC mesenchyme and the various levels of the neural axis from which visceral cartilages and bones originate have been established. In the present work, the contribution to the lower jaw and pharynx of NC mesenchymal derivatives other than bones and cartilages has been studied. It is shown that the dermis in the face and ventrolateral side of the neck has a neural origin. The wall of the large arteries deriving from the branchial arches (systemic aorta, pulmonary arteries, branchiocephalic trunks and common carotid arteries) are entirely made up of mesectodermal cells except for the endothelial epithelium which is mesodermal in origin. The presence in the wall of the common carotid arteries of fluoregenic monoamines-containing cells is demonstrated using the formol-induced-fluorescence technique. Like the secretory cells of the carotid body, the fluorescent cells of the carotid artery wall originate from the rhombencephalic NC. Connective tissue of the lower jaw, tongue and ventrolateral part of the neck originate from the neural crest. Mesectoderm participate in the formation of the glands associated with the tongue and pharynx (lingual gland, thymus, thyroid, parathyroids) giving their mesenchymal component. On the other hand, as demonstrated previously by our group, NC cells are the main cellular component of the UB since they give rise to the calcitonin producing cells. The wall of the oesophagus and trachea is of mesodermal origin, but adipose tissue around the trachea and parasympathetic enteric ganglia of the digestive tube derives from NC. NC cells participate in the formation of striated muscles of the branchial arches and differentiate there into connective and muscle cells. It appears from this study that the differentiating capabilities are similar in mesenchymal and mesectodermal cells with the exception of blood vessel endothelia which in our experiments are always of host origin in mesectoderm-derived tissues. The capacity of the NC to give rise to mesen chymal derivatives is restricted to the cephalic neural axis down to the level of the 5th somite in both chick and quail embryos.

Animals↗
PubMed2002

Minimal contribution of cell-bound antibodies to the immunoscintigraphy of inflamed joints with 99mTc-anti-CD4 monoclonal antibodies.

AIM: The cellular joint infiltrate in rheumatoid arthritis patients is rich in CD4-positive T-helper lymphocytes and macrophages, rendering anti-CD4 monoclonal antibodies (mAbs) suitable for specific immunoscintigraphy of human/experimental arthritis. Following intravenous injection, however, mAbs are present both in the free form and bound to CD4-positive, circulating monocytes and T-cells. Thus, the present study aimed at analyzing the relative contribution of the free and the cell-bound component to the imaging of inflamed joints in experimental adjuvant arthritis (AA). METHODS: AA rat peritoneal macrophages or lymph node l-cells were incubated in vitro with saturating amounts of 99mTc-anti-CD4 mAb (W3/25) and injected i.v. into rats with AA. RESULTS: In vitro release of 99mTc-anti-CD4 mAb from the cells was limited (on average 1.57%/h for macrophages and 0.84%/h for T-cells). Following i.v. injection, whole body/joint scans and tissue measurements showed only negligible accumulation of radioactivity in inflamed ankle joints (tissue: 0.22 and 0.34% of the injected activity, respectively), whereas the radioactivity was concentrated in liver (tissue: 79% and 71%, respectively), kidney, and urinary bladder. Unlike macrophages, however, anti-CD4 mAb-coated T-cells significantly accumulated in lymphoid organs, the inflamed synovial membrane of the ankle joints, as well as in elbow and knee joints. CONCLUSION: While the overall contribution of cell-bound mAbs to the imaging of arthritic joints with anti-CD4 mAbs is minimal, differential accumulation of macrophages and T-cells in lymphoid organs and the inflamed synovial membrane indicates preferential migration patterns of these 2 cell populations in arthritic rats. Although only validated for 99mTc-anti-CD4 mAbs, extrapolation of the results to other anticellular mAbs with similar affinity for their antigen may be possible.

Animals↗
PubMed1995

Human rotavirus subgroups and severity of associated diarrhoea in Ghana.

In a 12 month study of children with acute diarrhoea seeking medical care in 2 hospitals in Accra, Ghana, 16.3% were found to be infected with human rotaviruses (HRV). Vomiting and diarrhoea were the main symptoms observed. HRV infection was frequently associated with severe diarrhoea. Vomiting was however less frequent in HRV associated diarrhoea than in non HRV diarrhoea. No significant association was observed between the severity of dehydration and HRV infection. Subgroup II HRV was the predominant subgroup identified with the dominant serotypes being HRV serotypes 1 and 4. Poly-acrylamide gel electrophoresis of HRV RNAs isolated from 40 positive stool samples revealed the existence of 7 distinct electrophoretic migration patterns in the study population.

Journal Article↗
PubMed2002

[Euphausiids (Crustacea: Melacostraca) from the southern Mexican Caribbean Sea].

The composition, abundance and distribution of euphausiids from the southern part of the Mexican Caribbean Sea (August 1986) were sampled during the ARCOMM I cruise on board the R/V "Justo Sierra" of UNAM. Sampling was done using a Bongo-net (0.5 mm mesh size) performing oblique hauls from 200 m to the surface at 28 stations. Of the total euphausiid numbers, the most abundant species was Stylocheiron carinatum (49%), followed by Euphausia americana (9.8%) and E. tenera with (7.8%). The highest total density and that of the three most abundant species occurred during the night sampling, and probably was related to vertical migration patterns. The Bray-Curtis index revealed three station assemblages, related to the day-night variations of the euphausiid community. Species were distributed mainly in the oceanic area, and were absent in the neritic zones. The local fauna shows a strong affinity for the euphausiid community of the Gulf of Mexico and other areas of the Caribbean Sea. Four species are considered to be new records for the western Caribbean Sea.

Animals↗
PubMed1999

[Extraction and characterization of the lipopolysaccharide of Bartonella quintana]

Bartonella quintana has been reported as the cause of trench fever, persistent endocarditis, bacteriaemia and has been isolated with an increasing incidence in clinical specimens from AIDS patients. One of the main pathogenic factors of gram-negative bacteria, including B. quintana, is the lipopolysaccharide (LPS). However, very little information is available on the features of Bartonella LPS. The aim of the present study was to extract, purify and characterise B. quintana LPS. The effect of the LPS under scrutiny was also evaluated on TNFa release by means of the "in vitro" human whole blood model of sepsis. The Oklahoma strain of B. quintana was grown on sheep blood agar, at 37 C, in a moist atmosphere containing 5% carbon dioxide. Cells were harvested and washed in sterile and apyrogenic saline solution and LPS extracted following the procedure of Westphal e Jann (1965), modified by Minnick (1994). The LPS of B. quintana showed the migration pattern of a deep rough chemotype, and the chromogenic limulus amoebocyte lysate test (LAL test) revealed strong reactivity at low concentrations (6.2 pg/ml). Samples of human whole blood stimulated by 1000 ng/ml of B. quintana LPS released 1707 378 pg/ml of TNFa.

Journal Article↗