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Biomedical subjects

W H Lewis

Publications and source records attributed to W H Lewis.

At least 19 recordsLinked to original sources
PubMed1992

The gene for a novel protein, a member of the protein disulphide isomerase/form I phosphoinositide-specific phospholipase C family, is amplified in hydroxyurea-resistant cells.

Cell lines selected in multiple steps for increasing resistance to hydroxyurea have been shown to have corresponding increases in ribonucleotide reductase activity. We have isolated a number of cDNA clones from a cDNA library constructed from a highly hydroxyurea-resistant hamster cell line, 600H, in which the activity of ribonucleotide reductase is elevated more than 80-fold. These clones correspond to genomic DNA sequences amplified in the 600H cell line compared with the V79 parental line. One of these cDNA clones, termed P5, codes for a 50 kDa protein detected by in vitro translation of poly(A)+ RNA isolated by hybridization/selection. The cDNA sequence contains a single open reading frame of 1317 nucleotides which encodes a polypeptide of 439 amino acids. The amino acid sequence deduced from the cDNA insert contains two copies of the 11-amino-acid sequence Val-Glu-Phe-Tyr-Ala-Pro-Trp-Cys-Gly-His-Cys. Duplicate copies of this sequence also occur in the active site of rat and human protein disulphide isomerase (also known as the beta-subunit of human prolyl 4-hydroxylase, tri-iodothyronine-binding protein) and in Form I phosphoinositide-specific phospholipase C, indicating that P5 falls into this newly defined superfamily of proteins. Genomic sequences similar to the cDNA clone are amplified 10-20-fold in hamster cells selected for resistance to increasing concentrations of hydroxyurea, a phenomenon observed earlier with cDNA clones for the M2 subunit of ribonucleotide reductase and ornithine decarboxylase. RNA blots probed with P5 cDNA show two poly(A)+ RNA species which are elevated in hydroxyurea-resistant cells.

Amino Acid Sequence↗
PubMed1992

The allergens of Epicoccum nigrum Link. I. Identification of the allergens by immunoblotting.

Two atmospheric isolates of Epicoccum nigrum (EN) were grown under sporulation conditions. Dialyzed extracts of spores, (greater than 95% pure) and pure mycelia were used for skin testing, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and immunoblotting. By skin testing, 49 of the 126 atopic patients were found to be sensitive to EN in St. Louis, Mo., and Corpus Christi, Texas, combined. On immunoblotting, which was performed on 17 sera, 44 bands (12.3 to 119.0 kd) were detected; six were unique to spore, four were unique to mycelium, and 34 were common to both. No single band bound IgE from all sera. The most frequent band corresponding to 42 kd occurred in 11 sera. Five other bands were recognized by more than one half, whereas the remainder bound fewer sera. All skin test-positive patients had positive immunoblots; the number of bands recognized varied from three to 25. Spore or mycelium-specific, as well as common bands were recognized by 13 of 17 sera. Two sera recognized only spore and mycelium-specific bands. Only spore-specific bands were bound by two sera. No strain differences were detected. The binding patterns were comparable in the sera from both St. Louis, Mo., and Corpus Christi, Texas. These data suggest that EN is a significant allergen in urban communities. Allergenic proteins occur in both spore and mycelium, suggesting that both must be included in the reagents for skin testing and immunotherapy.

Air Microbiology↗
PubMed1992

Grass aeropollen of the western United States Gulf Coast.

Volumetric air sampling was performed at Corpus Christi, Tex., September 1987 to August 1989. Grass aeropollen during all of 1988 accounted for 15.3% of total pollen captured during two major peaks, one in May and another during September and October. The remaining grass pollen, about one-quarter of the total, was found throughout the year with low levels in the winter and mid-summer. This bimodal pollen release corresponds to the flowering of two major types of grasses occurring in the western Gulf Coast region, the cool temperate species which are predominantly spring flowering in response to long-day photoperiodicity, and the more common warm temperate and subtropical species flowering by and large in the fall as short-day plants. Supplementing the already rich grass flora and adding to the high proportion of total aeropollen was the long distance dispersal of grass pollen found perhaps in sufficiently high quantities to trigger allergic symptoms and to cause grass pollinosis out of season, at least in acutely sensitive individuals. This occurred in late March, well before the spring peak in May. Correlations existed between near-drought conditions and reduced pollen shed in 1988, and normal precipitation and much higher pollen shed during parts of 1987 and 1989, illustrating the importance of environmental factors such as moisture on annual pollen frequency and level of pollinosis which can be variable and annually unpredictable. What is predictable is the genetically controlled timing of pollen maturation and release which will be generally the same year by year.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed1992

The effect of divalent metal ions on the thermostability of C3.

Thermostability studies on human complement component C3 showed that saturation of the electronegative sites in the C3 molecule with divalent cations offered some protection against heat denaturation, a finding not previously reported in the literature. To inactive C3 in about 30 minutes, the required temperature was 61 degrees C in the presence of excess Ca2+ ions, 59.5 degrees C in the presence of excess of Mg2+ ions, but only 54 degrees C in the absence of these ionized metal ions.

Calcium↗
PubMed1991

Guanidinium-induced differential kinetic denaturation of alkaline phosphatase isozymes.

This paper examines the solution kinetics of bovine intestinal and liver alkaline phosphatase (ALP) isozymes. 4-Methylumbelliferyl phosphate is used as the substrate to study the differential kinetic behavior of ALP isozymes in the presence of guanidinium hydrochloride, a denaturant. The recursive Kalman filter algorithm for parameter estimation is used for analysis of the resulting kinetic data. A two-component first-order kinetic model with a zero-order component is used to successfully quantify intestinal and liver isozymes in synthetic mixtures. This work serves as a basis for the development of an electrophoresis separation method for ALP isozyme quantification with differential kinetic detection.

Alkaline Phosphatase↗
PubMed1991

Light-chain ratio of serum IgA1 in IgA nephropathy.

Patients with primary IgA nephropathy have deposits of IgA1 in their kidneys and increased IgA1 in circulation. We had previously shown that IgA nephritic patients displayed a unique immunological response characterized by a predominance of IgA with lambda chain in glomerular deposits and in circulation. We have now studied the kappa/lambda (kappa/lambda) ratio of serum IgA1 in 21 IgA nephritic patients at quiescence, with 11 patients investigated during exacerbation as well. A novel enzyme-linked immunosorbent assay was used with monoclonal mouse anti-human IgA1 as the solid-phase capture antibody and peroxidase-labeled anti-human kappa and lambda antibodies as tracers. The ratio of serum IgA1 to total IgA (mean +/- SD) was significantly higher in patients (90.1 +/- 8.2% at quiescence, P less than 0.01; 88.7 +/- 8.1% during exacerbation, P less than 0.02) than in 20 healthy age- and sex-matched controls (80.0 +/- 9.8%). Furthermore, serum IgA1 kappa/lambda ratios were significantly lower in patients (1.02 +/- 0.27 at quiescence, P less than 0.01; 0.93 +/- 0.16 during exacerbation, P less than 0.01) than in controls (1.31 +/- 0.30). These findings indicate a predominance of lambda light-chain IgA1 in the serum of IgA nephritic patients. However, no difference in IgA1 kappa/lambda ratio was observed in these patients at quiescence and during exacerbation.

Adolescent↗
PubMed1991

Autosomal recessive inheritance of myopia in Hong Kong Chinese infants.

Hong Kong Chinese infants were refracted by retinoscopy at regular intervals between the age of approximately 10 and 40 weeks. Cyclopentolate 1% was used to obtain cycloplegia. The spherical equivalent of the refractive error was calculated for each child and analysis of variance carried out according to the refractive status of the parents. From approximately 20 weeks of age a significant difference was found between the mean spherical equivalent of the refractive error of infants of parents both of whom were myopic and that of infants of parents neither of whom was myopic. At 40 weeks of age a good fit with an autosomal recessive probability model was obtained.

Adult↗
PubMed1991

Asteraceae aeropollen of the western United States Gulf Coast.

Volumetric air sampling was performed near Corpus Christi, Texas during 1988 and supplemented with data from 1987 and 1989. Frequencies of captured pollen grains of Parthenium hysterophorus, Ambrosia and allied genera, Helianthus, and other Asteracea were examined. Asteraceous aerospora in 1988 accounted for 22.1% of all pollen found, of which 83.4% were pollen of Ambrosia, 12.4% of Parthenium, and the remainder (4.1%) representative of other genera. Capture of native Ambrosia species and P. hysterophorus peaked in September and October in 1987 and 1988, but Parthenium pollen was also found year round with a smaller secondary peak during May, 1988 and 1989. In the winter a different Ambrosia pollen was captured which compared with A. hispida found in the Yucatan Peninsula and southern Florida at a time when no ragweed was flowering in the vicinity of Corpus Christi. Such a pollen capture probably represents long distance dispersal (ca. 600 miles, 965 km) on strong easterly to southerly prevailing winds. Pollen capture occurred most frequently during daylight hours when percent relative humidity was lower and near midnight when inversions occur. Comparison of pollen capture with meteorologic data demonstrated that photoperiodic responses probably account for the initiation and termination of Ambrosia flowering, and to some extent that of Parthenium, and not sharply lowered temperatures or frost for ending pollen release. Previous plant surveys have shown that P. hysterophorus is more common in the Corpus Christi area than species of Ambrosia, or any other Asteraceae, even though ragweed pollen capture proved 6.9 times greater. This disparity is most likely due to limited long distance dispersal of Parthenium pollen, less pollen produced per another, and a less developed mechanism of wind pollination (passive dispersal or amphiphilous). Since both Parthenium and Ambrosia are significant allergenic plants, correlations between airborne pollen of Parthenium and allergic potential suggest that a prolonged pollination season and perhaps increased allergenicity of unique Parthenium pollen proteins allow Parthenium to be a major allergen despite significantly less ambient pollen.

Air Pollution↗
PubMed1991

Aeropollen of weeds of the western United States Gulf Coast.

Volumetric air sampling was performed near Corpus Christi, Texas during all of 1988. The most significant weeds releasing airborne pollen, besides the Asteraceae, were the Amaranthaceae and Chenopodiaceae at 14.8% of total pollen captured, which peaked in September and October. Greater pollen capture (74%) occurred from a peak at 11 PM at a time when inversions are frequent to 9 AM than during the period from late morning to 9 PM. Frequency of amaranth-chenopod pollen capture in the western Gulf Coast region showed no relationship with frequencies along the northern and eastern Gulf Coast nor in eastern North America generally, but rather with western North America where these grains have also been sampled at high levels. As in the West, therefore, amaranth-chenopod aeropollen is sufficiently frequent to be a major source of allergens in the western Gulf Coast region. Other weedy plants, Cannabis/Humulus, Rumex, and the Urticaceae (Parieteria/Urtica) each account for only about 1% of the total annual pollen shed, and consequently they are not nearly as potentially relevant here in pollinosis as are the amaranth-chenopods and Asteraceae. Plantago pollen is very infrequently sampled (less than 0.1%) even though several species are common in the area. Acalypha is newly reported as releasing airborne pollen, a genus related to Mercurialis known to release allergenic pollen in Europe.

Air Pollution↗
PubMed1991

Human xanthine oxidase antibody levels: variation between males and females in Chinese and Europeans.

Levels of antibody specific for Xanthine oxidase (XODAb) of the immunoglobulin classes IgG, IgM and IgA have been determined in the sera of blood donors of Chinese and European ethnic origin by immunoassay. No significant differences were found between the two ethnic groups. Significant differences were found in the distribution, of XODAb IgM levels between Chinese males and females and European males and females (chi 2 = 8.262, P = 0.025; chi 2 = 9.423, P = less than 0.001). Since the age range of the female blood donors is 16-49 years, it was postulated that the higher IgM XODAb levels in the females was the result of autoimmunisation by endothelial Xanthine oxidase during menstruation. A group of post-menopausal women showed significantly lower IgM XODAb levels compared to the blood donors (chi 2 = 31.748, P = less than 0.0005). IgM levels in a group of older men were also significantly lower (chi 2 = 3.895, P = less than 0.05) but the difference was much less marked. Unlike the younger males and females there was no significant difference in the distribution of XODAb IgM levels between older males and females. The results seem to support the hypothesis of menstrual auto-immunisation.

Adolescent↗
PubMed1990

High-performance liquid affinity chromatography for the purification of immunoglobulin A from human serum using jacalin.

A high-performance liquid affinity chromatographic method for the purification of serum immunoglobulin A (IgA) using a jacalin column is described. The automated procedure takes about 2 with minimal manipulation. The yields of the isolated IgA and of its IgG and IgM contamination were studied by enzyme-linked immunosorbent assay (ELISA) of 30 sera. Purity was assured by immunoelectrophoresis. The ratio of IgA1 to total IgA was unchanged after purification, as verified by ELISA. The results showed that greater than 90% IgA could be recovered with less than 0.5% total IgG and greater than 2.0% total IgM remaining in the fractions containing purified IgA.

Chromatography, Affinity↗
PubMed1990

Complete physical map of the WAGR region of 11p13 localizes a candidate Wilms' tumor gene.

A complete physical map of the 11p13 region containing the Wilms' tumor locus has been developed and used to localize a candidate Wilms' tumor gene. Our strategy to construct the map combined the use of pulsed-field gel electrophoresis and irradiation-reduced somatic cell hybrids. These hybrids, which contain limited segments of human chromosome 11 segregated from the remainder of the human genome, permit direct visualization of restriction fragments located in 11p13 using human interspersed repeated DNA sequences as hybridization probes. The physical map has provided a framework to identify the sites of genes responsible for the complex of disorders associated with hemizygous 11p13 deletion: Wilms' tumor, aniridia, genitourinary abnormalities, and mental retardation. The Wilms' tumor locus has been limited to a region of less than 345 kb, and a transcript with many of the characteristics expected for the Wilms' tumor gene has been localized to this region.

Cell Line↗
PubMed1990

Isolation and characterization of a zinc finger polypeptide gene at the human chromosome 11 Wilms' tumor locus.

We have isolated a series of genomic and cDNA clones mapping within the boundaries of constitutional and tumor deletions that define the Wilms' tumor locus on human chromosome 11 (band p13). The transcription unit corresponding to these clones spans approximately 50 kb and encodes an mRNA approximately 3 kb long. This mRNA is expressed in a limited range of cell types, predominantly in the kidney and a subset of hematopoietic cells. The polypeptide encoded by this locus has a number of features suggesting a potential role in transcriptional regulation. These include the presence of four zinc finger domains and a region rich in proline and glutamine. The amino acid sequence of the predicted polypeptide shows significant homology to two growth regulated mammalian polypeptides, EGR1 and EGR2. The genetic localization of this gene, its tissue-specific expression, and the function predicted from its sequence lead us to suggest that it represents the 11p13 Wilms' tumor gene.

Amino Acid Sequence↗
PubMed1990

Hypertrophic scar: a genetic hypothesis.

Two groups of patients with surgical and thermal wounds respectively were tested for aldehyde dehydrogenase 2 deficiency and assessed for the degree of hypertrophy of their scars. No association was found between the deficiency and hypertrophy of the scar. The frequency of hypertrophy was found to be 0.914 in the thermal injury group and 0.446 in the surgical wound group. This difference is statistically significant. The frequency data of the degree of hypertrophy in the two groups has been used to develop and test a single gene hypothesis for the origin of hypertrophic scar in the local Chinese population. It is postulated that the allele responsible for hypertrophy behaves as a dominant allele in the thermal injury group and as a recessive in the surgical wound group for the induction of hypertrophy.

Aldehyde Dehydrogenase↗
PubMed1990

Enzyme-linked immunosorbent assay for determination of antibodies to xanthine oxidase.

An enzyme-linked immunosorbent assay (ELISA) was developed to detect IgG, IgA and IgM antibodies to xanthine oxidase. The method used xanthine oxidase to coat sample wells on microtitre plates. The anti-xanthine oxidase concentrations were determined by reference to standard curves constructed by coating plates with anti-IgG, anti-IgA and anti-IgM to capture antibodies of different classes in standard human serum. The standard curves for IgG, IgA and IgM had a working range of 0 to about 60 ng/ml, and all results with commercial quality control serum fell within expected ranges. The coefficients of variation (CV) for within-batch precision (n = 30) and between-batch precision (n = 20) for IgG and IgM were about 9% and 12% respectively. The detection limit was 2 ng/ml. The ELISA was applied to assay serum samples of 110 Chinese and 110 European healthy subjects. A positively-skewed distribution in their anti-xanthine oxidase IgG and IgM levels was observed.

Antibodies↗
PubMed1989

The T-cell receptor delta chain locus is disrupted in the T-ALL associated t(11;14)(p13;q11) translocation.

Two T-ALL patients carrying a t(11;14)(p13;q11) translocation were analyzed. Southern blotting experiments demonstrated that both patients had rearranged their J delta genes and that the translocation involved the delta locus in both cases. In one patient, cloning, restriction mapping, and sequencing showed that the translocation occurred on a D delta 1-D delta 2-J delta 2 rearranged gene. In addition, the rearrangement on chromosome 11 occurred in both patients within a segment of less than or equal to 2 kb showing the presence in this region of a point of recurrent recombination.

Base Sequence↗
PubMed1989

A fine-structure deletion map of human chromosome 11p: analysis of J1 series hybrids.

Deletion analysis offers a powerful alternative to linkage and karyotypic approaches for human chromosome mapping. A panel of deletion hybrids has been derived by mutagenizing J1, a hamster cell line that stably retains chromosome 11 as its only human DNA, and selecting for loss of MIC1, a surface antigen encoded by a gene in band 11p13. A unique, self-consistent map was constructed by analyzing the pattern of marker segregation in 22 derivative cells lines; these carry overlapping deletions of 11p13, but selectively retain a segment near the 11p telomere. The map orders 35 breakpoints and 36 genetic markers, including 3 antigens, 2 isozymes, 12 cloned genes, and 19 anonymous DNA probes. The deletions span the entire short arm, dividing it into more than 20 segments and define a set of reagents that can be used to rapidly locate any newly identified marker on 11p, with greatest resolution in the region surrounding MIC1. The approach we demonstrate can be applied to map any mammalian chromosome. To test the gene order, we examined somatic cell hybrids from five patients, whose reciprocal translocations bisect band 11p13; these include two translocations associated with familial aniridia and two with acute T-cell leukemia. In each patient, the markers segregate in telomeric and centromeric groups as predicted by the deletion map. These data locate the aniridia gene (AN2) and a recurrent T-cell leukemia breakpoint (TCL2) in the marker sequence, on opposite sides of MIC1. To provide additional support, we have characterized the dosage of DNA markers in a patient with Beckwith-Wiedemann syndrome and an 11p15-11pter duplication. Our findings suggest the following gene order: TEL - (HRAS1, MER2, CTSD, TH/INS/IGF2, H19, D11S32) - (RRM1, D11S1, D11S25, D11S26) - D11S12 - (HBBC, D11S30) - D11S20 - (PTH, CALC) - (LDHA, SAA, TRPH, D11S18, D11S21) - D11S31 - D11S17 - HBVS1 - (FSHB, D11S16) - AN2 - MIC1 - TCL2 - delta J - CAT - MIC4 - D11S9 - D11S14 - ACP2 - (D11S33, 14L) - CEN. We have used the deletion map to show the distribution on 11p of two centromeric repetitive elements and the low-order interspersed repeat A36Fc. Finally, we provide evidence for an allelic segregation event in the hamster genome that underlies the stability of chromosome 11 in J1. The deletion map provides a basis to position hereditary disease loci on 11p, to distinguish the pattern of recessive mutations in different forms of cancer and, since many of these genes have been mapped in other mammalian species, to study the evolution of a conserved syntenic group.

Animals↗