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Biomedical subjects

B Eng

Publications and source records attributed to B Eng.

At least 19 recordsLinked to original sources
PubMed2002

Self-calibration of biplanar radiographs for a retrospective comparative study of the 3D correction of adolescent idiopathic scoliosis.

A novel technique for the 3D reconstruction of the spine from X-ray images is presented. The algorithm is based on the self-calibration of biplanar radiographs. It allows the 3D reconstruction of spines from old uncalibrated preoperative and postoperative radiographs. The reliability of the new self-calibration technique was investigated by validating its results against those of the Direct Linear Transform (DLT) on real images. An accuracy experiment was also performed using a dry spine specimen under controlled conditions. The results indicate that self-calibration is a viable technique, accurate enough to extract meaningful 3D clinical data for retrospective studies.

Adolescent↗
PubMed2001

Frequency and ethnic distribution of the common DHCR7 mutation in Smith-Lemli-Opitz syndrome.

Smith-Lemli-Opitz syndrome (SLOS) is an inherited multiple malformation syndrome caused by enzymatic deficiency of 3beta-hydroxysterol-Delta(7)-reductase (DHCR7). SLOS is thought to be most common among European Caucasians, with an incidence of 1 in 20,000 to 1 in 30,000 births. To define the carrier rate and ethnic distribution of SLOS, we screened DNA samples from 2,978 unrelated individuals for the most common SLOS mutation (IVS8-1G-->C). Twenty-four heterozygotes of the IVS8-1G-->C mutation were detected in 2,978 individuals of European Caucasian and Black backgrounds. For European Caucasians, the carrier rate for SLOS may be as high as 1 in 30, suggesting an incidence of 1 in 1,700 to 1 in 13,400. This high number is supported by the recent observation of newborn and prenatal incidence of 1 in 22,000 in the Caucasian population. Ours is the first report of the IVS8-1G-->C mutation in persons of African ancestry. Published 2001 Wiley-Liss, Inc.

Europe↗
PubMed2001

DHCR7 genotypes of cousins with Smith-Lemli-Opitz syndrome.

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder of cholesterol biosynthesis caused by mutations of the 7-dehydrocholesterol reductase gene (DHCR7). We report on three cousins with SLOS, all of whom were found to be compound heterozygotes for the common splice site mutation IVS8-1G-->C and the missense mutation T289I. DNA analysis of one set of parents demonstrated that the father carried the missense mutation and the mother carried the IVS8-1G-->C mutation. By extension, the two unrelated mothers were both heterozygous for IVS8-1G-->C. This finding supports the notion of a high carrier frequency of the IVS8-1G-->C null mutation in Northern European Caucasians.

DNA Mutational Analysis↗
PubMed2001

Hemoglobin H (Hb H) disease in Canada: molecular diagnosis and review of 116 cases.

Over the past decade, we have characterized at the DNA level a total of 116 hemoglobin H (Hb H) disease patients living in Canada. The majority of patients were of southeast Asian descent (Chinese, Filipino, Laotian, Vietnamese), with a small number being of Mediterranean, Middle Eastern or East Indian background. A total of 15 distinct genotypes were detected, all but one being compound heterozygotes for a two-gene cis deletion and a single-gene deletion (-alpha/-) or a non-deletion mutation of the alpha2-globin gene (alpha(T) alpha/-). Seven different two-gene cis deletions were encountered, along with nine single-gene deletions and point mutations. The wide range of mutations associated with Hb H disease in Canada is a reflection of the population heterogeneity. The diagnosis of Hb H disease at the molecular level is important with respect to genetic counseling and the identification of families at risk for having pregnancies affected with Hb Bart's hydrops fetalis syndrome and/or Hb H disease. Six of the Hb H disease patients in our cohort had spouses who carried single-gene deletions, making these couples at risk for having children with Hb H disease. More important, seven patients had partners who carried two-gene cis deletions. These couples are at reproductive risk for both Hb Bart's hydrops fetalis syndrome and Hb H disease.

Adolescent↗
PubMed2001

Hb H hydrops foetalis syndrome: a case report and review of literature.

Haemoglobin H (Hb H) disease is caused by deletion or inactivation of three alpha-globin genes, leaving only one intact and active alpha-globin gene. People with Hb H disease usually have moderate anaemia, but are generally thought to be asymptomatic. Some Hb H disease patients require transfusions, and there are reports of fetuses with Hb H disease who have severe anaemia in utero resulting in fatal hydrops foetalis syndrome. We now report a case of Hb H hydrops foetalis syndrome, caused by the inheritance of a hitherto novel alpha-globin gene point mutation (codon 35 TCC-->CCC or Serine-->Proline) and an alpha-thalassaemia deletion of the Filipino type removing all zeta-alpha-globin genes on the other chromosome 16. The infant was delivered prematurely because of pericardial effusion and fetal distress, and was found to have severe anaemia and congenital anomalies. A review of the relevant literature on this syndrome is presented, and serves to underscore the phenotypic variations of Hb H disease and the need for surveillance for this condition among newborns and genetic counselling in communities with a high proportion of at-risk populations.

Base Sequence↗
PubMed2001

Identification of two new alpha-thalassemia mutations in exon 2 of the alpha1-globin gene.

The most common causes of alpha-thalassemia are deletions that remove one or both of the functional alpha-globin genes. In addition, more than 30 different point mutations and small deletions/insertions have been reported for the alpha-globin genes. Here, we describe two new mutations occurring in exon 2 of the alpha1-globin gene. One mutation is an insertion of 21 bp that gives rise to a predicted alpha-globin chain containing a duplication of amino acid residues 93-99. The second mutation is a 33 bp deletion resulting in a predicted alpha-globin chain that is missing amino acid residues 64-74. Neither mutation results in a detectable hemoglobin variant, indicating that the variant alpha-globin chains are highly unstable. Carriers of these mutations have mild microcytosis and the phenotype of alpha+-thalassemia trait.

Base Sequence↗
PubMed2001

Detection of severe nondeletional alpha-thalassemia mutations using a single-tube multiplex ARMS assay.

Alpha-thalassemia is a common hereditary anemia due to decreased or absent synthesis of alpha-globin chains. The most common causes of alpha-thalassemia are deletions that remove one or both functional alpha-globin genes, with a small proportion of cases involving nondeletional mutations of the alpha2- or alpha1-globin genes. Herein, we describe a single-tube multiplex amplification refractory mutation system (ARMS) assay for rapid detection of six of the most common and severe nondeletional alpha-thalassemia mutations. These alleles are found predominantly among southeast Asian populations, and are associated with the most severe forms of hemoglobin (Hb) H disease or Hb H hydrops fetalis.

Globins↗
PubMed2001

Late-onset metachromatic leukodystrophy clinically presenting as isolated peripheral neuropathy: compound heterozygosity for the IVS2+1G-->A mutation and a newly identified missense mutation (Thr408Ile) in a Spanish family.

We report the case of a 50-year-old woman and her 32-year-old daughter, both of whom are affected with adult-onset metachromatic leukodystrophy (MLD) clinically presenting as peripheral neuropathy. Arylsulfatase A (ARSA) activities were markedly reduced, and electrophysiology showed a severe demyelinating neuropathy with features of chronic acquired demyelinating polyneuropathy. Molecular genetic studies of the family revealed that the proband and her affected daughter are compound heterozygotes for the common IVS2+ 1G-->A mutation and a newly identified missense mutation, Thr408Ile. This case indicates that adult metachromatic leukodystrophy should be considered in adult patients with demyelinating peripheral neuropathy of unknown etiology.

Alleles↗
PubMed2000

PCR-based diagnosis of the Filipino (--(FIL)) and Thai (--(THAI)) alpha-thalassemia-1 deletions.

In southeast Asia, the carrier frequency of two-gene alpha-thalassemia deletions is quite high, ranging from 4% to 14% depending on the population. The most common alpha-thalassemia-1 deletion is the so-called southeast Asian deletion (--(SEA)). In addition, a significant proportion of cases involve two other deletions, the Filipino (--(FIL)) and Thai (--(THAI)) deletions. In this report, we identify the deletion breakpoints for the (--(FIL)) and (--(THAI)) deletions, and describe PCR-based protocols for rapid and reliable DNA diagnosis of these deletions.

Asia, Southeastern↗
PubMed1999

A combined residency in family medicine and internal medicine at Eastern Virginia Medical School.

This paper describes the first operational four-year combined family medicine/internal medicine residency designed to qualify residents for board examination in both disciplines, which began at Eastern Virginia Medical School in 1995. The authors describe key program features, including their block rotation schedule, interdisciplinary ambulatory precepting, and plans for achieving 50% ambulatory training experience, as well as their difficulties in implementing a collaborative core didactic experience. The authors present faculty survey data indicating that internal medicine faculty members are more likely to view the combined residency as a resource, while family medicine faculty members would like to concentrate on the categorical residency. A recent survey of combined residents indicates that they are satisfied with their choice of combined training and optimistic about the opportunity of garnering additional skills relative to their internal medicine and family medicine counterparts. The authors suggest that successfully implementing this interdisciplinary effort requires an atmosphere of mutual respect and an effort to find opportunities to positively affect the training experiences of both combined residents and their resident partners in family medicine and internal medicine.

Curriculum↗
PubMed1998

Technical note: improved DNA extraction from ancient bones using silica-based spin columns.

We describe a simple method for extracting polymerase chain reaction-amplifiable DNA from ancient bones without the use of organic solvents. Bone powders are digested with proteinase K, and the DNA is purified directly using silica-based spin columns (QIAquick3, QIAGEN). The efficiency of this protocol is demonstrated using human bone samples ranging in age from 15 to 5,000 years old.

Animals↗