PubMed Health⌕ Search

Biomedical subjects

J B Wilson

Publications and source records attributed to J B Wilson.

At least 19 recordsLinked to original sources
PubMed1992

Heterozygosity for the IVS-I-5 (G-->C) mutation with a G-->A change at codon 18 (Val-->Met; Hb Baden) in cis and a T-->G mutation at codon 126 (Val-->Gly; Hb Dhonburi) in trans resulting in a thalassemia intermedia.

We have analyzed the hemoglobins of a young German patient with beta-thalassemia intermedia and of his immediate family and included in these studies an evaluation of possible nucleotide changes in the beta-globin genes through sequencing of amplified DNA. One chromosome of the propositus and one of his father's carried the GTG-->GGG mutation at codon 126 leading to the synthesis of Hb Dhonburi or alpha 2 beta (2)126(H4)Val-->Gly; this variant is slightly unstable and is associated with mild thalassemic features. His second chromosome and one of his mother's had the common IVS-I-5 (G-->C) mutation that leads to a rather severe beta(+)-thalassemia and the GTG-->ATG mutation at codon 18, resulting in the replacement of a valine residue by a methionine residue. This newly discovered beta-chain variant, named Hb Baden, was present for only 2-3% in both the patient and his mother. This low amount results from a decreased splicing of RNA at the donor splice-site of the first intron that is nearly completely deactivated by the IVS-I-5 (G-->C) thalassemic mutation. The chromosome with the codon 18 (GTG-->ATG) and the IVS-I-5 (G-->C) mutations has thus far been found only in this German family; analysis of 51 chromosomes from patients with the IVS-I-5 (G-->C) mutation living in different countries failed to detect the codon 18 (GTG-->ATG) change.

Amino Acid Sequence↗
PubMed1992

Heterogeneity of the hemoglobin of the Ohrid trout (Salmo L. typicus).

We have analyzed the hemoglobins of five individual trout from the Ohrid Lake (Salmo L. typicus) by electrophoretic methods, by reversed-phase high-performance liquid chromatography, and by limited structural analyses. The two major classes of hemoglobin are type I (35% of total) and type IV (65%). Type IV is the major oxygen-transporting hemoglobin; it consists of three types of beta chain (in about equal quantities) and three types of alpha chain (one major and two minor types). Several structural differences have been observed between these three beta (IV) chains and between the three alpha (IV) chains, suggesting a complex genetic system governing the synthesis of these proteins. Moreover, a few amino acid substitutions occur at positions involved in contacts between chains, which suggests that differences in oxygen affinity may exist between these various type IV hemoglobins. Type I hemoglobin is less complex because it contains one type of beta chain and two alpha chains; the latter two differ in numerous positions, suggesting duplications of the alpha (I)-globin gene. The alpha and beta chains of type I hemoglobin differ considerably from the alpha and beta chains of type IV hemoglobin, indicating the existence of alpha (I)- and beta (I)-globin genes separate from the alpha (IV)- and beta (IV)-globin genes.

Amino Acids↗
PubMed1992

Distribution and characteristics of verocytotoxigenic Escherichia coli isolated from Ontario dairy cattle.

Faecal swabs obtained from a random sample of 1131 cows and 659 calves on 100 southern Ontario dairy farms were examined for verocytotoxigenic Escherichia coli (VTEC) using a Vero cell assay. Five isolates from each positive culture were tested similarly. Positive colonies were examined with DNA probes for Shiga-like toxin I (SLT-I) and SLT-II sequences. Probe-negative colonies were tested for neutralization of verocytotoxicity using anti-SLT-I and anti-SLT-IIv antisera. Colonies showing no neutralization response were examined in a polymerase chain reaction procedure. Colonies positive by any test were confirmed to be E. coli biochemically, serotyped, biotyped and tested for antimicrobial resistance. Faecal culture supernatants which were positive in the Vero cell assay, but culture negative, were examined using the neutralization assay. Animals were classified positive by faecal culture supernatant or by positive VTEC isolate. The prevalence rates of VTEC infection in cows and calves were estimated to be 9.5 and 24.7%, respectively. The proportion of animals infected on each farm ranged from 0 to 60% for cows and 0 to 100% for calves. Of 206 VTEC isolates identified, few were of serotypes which have been isolated from humans and none were E. coli O 157.H7.

Animals↗
PubMed1992

Hb Graz or alpha 2 beta 2(2)(NA2)His-->Leu; a new beta chain variant observed in four families from southern Austria.

Two abnormal hemoglobins were accidentally detected by cation exchange high performance liquid chromatography with the Diamat system of Bio-Rad Laboratories; the variants eluted together with the fast-moving Hb A1c. Structural analysis of isolated beta chains and sequence analysis of amplified DNA identified a new variant, i.e. Hb Graz that has a His-->Leu replacement at position 2 of the beta chain, in four healthy, apparently unrelated, adults. The second variant was identical to Hb Sherwood Forest or alpha 2 beta 2(104)(G6)Arg-->Thr; it is believed that this may be the second observation of this abnormal hemoglobin.

Amino Acid Sequence↗
PubMed1992

A new variant, HB Muscat [alpha 2 beta (2)32(B14)Leu----Val] observed in association with HB S in an Arabian family.

The silent Hb Muscat with a Leu----Val replacement at position beta 32 was discovered by reversed phase high performance liquid chromatography in two members of an Arabian family from Oman; in one person Hb Muscat occurred with Hb S and in the other with Hb A. Hb Muscat is slightly unstable but its presence has no apparent adverse effect on the health of its carriers. Additional hemoglobin abnormalities observed in this family were a common alpha-thalassemia-2 (-3.7 kb) and Hb S. The beta S haplotypes in the heterozygous carriers and the two sickle cell anemia patients were #19 (Benin) and #20 (Bantu); the latter likely originated from an East African population.

Adolescent↗
PubMed1992

Hb Bab-Saadoun or alpha 2 beta (2)48(CD7)Leu----Pro, a mildly unstable variant found in an Arabian boy from Tunisia.

Hb Bab-Saadoun which has a Leu----Pro substitution at position 48 of the beta chain was detected in a young Arabian boy living in Tunisia. His parents did not have the variant which suggests that it occurred as a spontaneous mutation. The substitution is located in the interhelical CD segment; leucine at beta 48 is an invariable amino acid that may be important as part of a spacer sequence between the two helices and its replacement by proline may affect the stability of the hemoglobin molecule. Hb Bab-Saadoun is unstable in heat and isopropanol stability tests and its chain was best isolated by parachloromercuribenzoate precipitation. It appears unlikely that the presence of Hb Bab-Saadoun results in a hemolytic anemia.

Adolescent↗
PubMed1992

The unstable Hb Hammersmith or alpha 2 beta 2(42)(CD1)Phe----Ser observed in an Indian child; identification by HPLC and by sequence analysis of amplified DNA.

We have identified the unstable hemoglobin variant present in a Chipewayan Indian patient with severe hemolytic anemia as Hb Hammersmith or alpha 2 beta 2(42)(CD1)Phe----Ser. Her parents were normal. Identification was greatly facilitated by the use of reversed phase high performance liquid chromatography for the isolation of the beta X chain and its tryptic fragments, and of sequence analysis of amplified DNA which readily identified a TTT(Phe)----TCT(Ser) mutation at codon 42.

Base Sequence↗
PubMed1992

Types of thalassemia among patients attending a large university clinic in Kuala Lumpur, Malaysia.

We have identified the beta-thalassemia mutations in 59 patients with thalassemia major and 47 patients with Hb E-beta-thalassemia, and the deletional and nondeletional alpha-thalassemia determinants in 23 out of 24 patients with Hb H disease. All persons were attending the Haematology Clinic at the National University of Malaysia in Kuala Lumpur (Malaysia). Most patients (76) were of Malay descent, while 52 patients were Chinese, and two came from elsewhere. The most frequently occurring beta-thalassemia alleles among the Malay patients were IVS-I-5 (G----C) and G----A at codon 26 (Hb E), while a few others were present at lower frequencies. The Chinese patients carried the mutation characteristic for Chinese [mainly codons 41/42 (-TTCT) and IVS-II-654 (C----T)]; Malay mutations were not observed among Chinese and Chinese mutations were virtually absent in the Malay patients. The large group of patients with Hb E-beta-thalassemia and different beta-thalassemia alleles offered the opportunity of comparing hematological data; information obtained for patients with Hb E-beta-thalassemia living in other countries was included in this comparison. Twenty-three patients with Hb H disease carried the Southeast Asian (SEA) alpha-thalassemia-1 deletion; 13 had the alpha CS alpha (Constant Spring) nondeletional alpha-thalassemia-2 determinant, while the deletional alpha-thalassemia-2 (-3.7 or -4.2 kb) was present in 10 subjects. The --/alpha CS alpha condition appeared to be the most severe with higher Hb H values. Both deletional and nondeletional types of alpha-thalassemia-2 were seen among Malay and Chinese patients.

Academic Medical Centers↗
PubMed1992

A second observation of the fetal methemoglobin variant Hb F-M-Fort Ripley or alpha 2G gamma 2(92)(F8)His----Tyr.

We have identified a second baby with the fetal methemoglobin F-M-Fort Ripley. It was observed in a Caucasian infant from Canada; at least eleven additional members of that family were known to have had a neonatal cyanosis similar to that seen in the propositus and in a previously described baby (2). Sequencing of amplified DNA that included (part of) the G gamma gene greatly facilitated the characterization. The G gamma X chain was readily isolated by reversed phase high performance liquid chromatography; its quantity was approximately 12.5% of total gamma. Interestingly, the baby also carried the A gamma T mutation on one chromosome, either in cis or in trans to the G gamma X mutation. Hb F-M-Fort Ripley could be isolated in reasonably pure form by DEAE-cellulose chromatography. The isolated Hb FX was unstable, had spectral changes characteristic for the M-hemoglobins, while its methemoglobin derivative reacted rapidly with cyanide. Oxygen affinity data could not be obtained. It is suggested that the formation of a rather large amount (approximately 25%) of mixed hybrids (alpha 2G gamma X.gamma) with low oxygen affinity is the main cause for the occurrence of the neonatal cyanosis.

Base Sequence↗
PubMed1992

Comparative studies of live neonates in maternal sickle cell haemoglobinopathy in Ghana.

This study assessed the current status of live neonates born to sickle cell mothers when compared with those of normal (control) women. Birth weight, placental weight, fetoplacental ratio, and gestational age for live neonates in singleton births by twenty-nine haemoglobin SS (HbSS), fifty-two haemoglobin SC (HbSC), and fifty-one (normal) haemoglobin AA (HbAA) mothers were statistically compared. Neonates of HbSS mothers had a statistically lower than normal mean birth weight and gestational age, but only a shorter mean gestation significantly distinguished those of the HbSC and HbAA mothers. Inferentially, neonates delivered by HbSS women were both underweight and preterm, whereas those of HbSC women were preterm but not underweight, and apparently large for gestational age (LGA). No statistical differences were found between neonates in terms of placental weights or fetoplacental ratios.

Anemia, Sickle Cell↗
PubMed1992

A case-control study of selected pathogens including verocytotoxigenic Escherichia coli in calf diarrhea on an Ontario veal farm.

A case-control study of diarrheal disease in veal calves was conducted over a three month period on a single large veal farm in southern Ontario. One hundred diarrheic calves (cases) were identified by visual examination of their feces. Each case was matched to two nondiarrhetic controls from the same room on the same day, and a fecal sample was obtained from each animal. Fecal consistency of cases and controls was observed daily for one week following sample collection. Control calves which developed diarrhea during that period were excluded from the study. Breed, sex and the date and nature of antimicrobial drugs administered to each calf were recorded. Moisture content of fecal samples was measured by weighing samples before and after oven drying. Samples were screened for verocytotoxigenic Escherichia coli (VTEC) using a Vero cell assay, for enterotoxigenic E. coli (ETEC) using an immunoblot procedure with anti-K99 monoclonal antibodies, and for Salmonella species using modified semi-solid Rappaport-Vassiliadis medium. A latex agglutination test was used to detect rotaviruses, and samples were examined for cryptosporidia using sucrose wet mounts. No VTEC were identified in cases or controls. One calf was positive for Salmonella and three were positive for ETEC. Rotaviruses were detected in four cases and four controls. A significant positive association was found between diarrhea and infection with Cryptosporidium. This study thus provided no evidence of an association between diarrhea and infection with either VTEC, ETEC, Salmonella spp. or rotaviruses in the population examined. On the other hand our results do suggest that Cryptosporidium infection may promote transient diarrheal disease in veal calves in Ontario.

Animals↗
PubMed1991

Hemoglobin Montreal: a new variant with an extended beta chain due to a deletion of Asp, Gly, Leu at positions 73, 74, and 75, and an insertion of Ala, Arg, Cys, Gln at the same location.

The unstable hemoglobin Montreal with a deletion of three amino acid residues (Asp, Gly, Leu) at positions 73, 74, and 75 of the beta chain and an insertion of four residues (Ala, Arg, Cys, Gln) at the same location was observed in a 7-year-old Canadian boy suffering from a moderate hemolytic anemia. The introduction of an extra amino acid residue and of other changes in the crevice where the heme group is located is the likely cause of the instability of this hemoglobin variant. The above listed changes were detected through analyses of tryptic peptides of the beta-Montreal chain, sequencing of amplified DNA, and hybridization of amplified DNA with appropriate, 32P-labeled, oligonucleotide probes. It is suggested that a mispairing involving the AGTG sequences at codons 66 and 67 and at codons 72 and 73 of the normal beta gene caused a repetition of a 16-bp segment, while a deletion of 10 nucleotides due to recombination or slippage followed by a second short deletion during DNA repair resulted in the modified sequence of the beta-Montreal gene.

Adult↗
PubMed1991

The linkage of Hb Valletta [alpha 2 beta 287(f3)Thr----Pro] and Hb F-Malta-I [alpha 2G gamma 2117(G19)His----Arg] in the Maltese population.

We have identified a new stable abnormal hemoglobin called Hb Valletta, which is characterized by a Thr----Pro substitution at position 87 of the beta chain. This mutation was found to be linked to that of the gamma chain variant Hb F-Malta-I with a His----Arg mutation at position 117 of the G gamma chain. Both variants were detected in the blood samples of 34 Maltese and two Italian newborn babies with isoelectrofocusing and reversed phase high performance liquid chromatography. Similar analyses of cord blood from 388 additional Maltese newborns failed to identify either one of these two variants. Additional analyses of 353 Maltese adults (including 39 beta-thalassemia heterozygotes) resulted in the detection of two adult Hb Valletta heterozygotes. Dot-blot hybridization analyses of amplified DNA with a probe specific for the G gamma-F-Malta-I variant showed that both also carried that mutation. These results show close linkage of the mutant forms of the G gamma- and beta-globin genes, 27-28 kb apart, and a failure to identify chromosomes with either the Hb F-Malta-I mutation alone or with the Hb Valletta mutation alone, indicating a low recombination frequency.

Adult↗