PubMed Health⌕ Search

Biomedical subjects

G D Ehrlich

Publications and source records attributed to G D Ehrlich.

At least 19 recordsLinked to original sources
PubMed2005

Mapping of an autosomal dominant gene for Dupuytren's contracture to chromosome 16q in a Swedish family.

Mapping of an autosomal dominant gene for Dupuytren's contracture to chromosome 16q in a Swedish family.Dupuytren's contracture (DC) (OMIM 126900) is the most common connective tissue disease of mankind and has both heritable and sporadic forms. The inherited form is most frequently observed among the xanthochroi peoples of Northern Europe where its most common manifestations are thickening of the palmar fascia and contracture of the fingers. We ascertained a five-generation Swedish family in which DC is inherited in an autosomal dominant manner with high, but incomplete, penetrance by the end of the fifth decade. Blood was collected from all affected and informative unaffected family members for the performance of a genome-wide scan at a resolution of approximately 8 cM for all autosomes. Linkage was established to a single 6 cM region between markers D16S419 and D16S3032 on chromosome 16. A maximal two-point logarithm of odds (LOD) score of 3.18 was achieved at microsatellite marker D16S415 with four other markers in the region producing LODs of >1.5.

Chromosome Mapping↗
PubMed2001

Century of Jackson-Weiss syndrome: further definition of clinical and radiographic findings in "lost" descendants of the original kindred.

Jackson-Weiss syndrome (JWS) is a condition consisting of craniosynostosis characterized by premature fusion of the cranial sutures and/or characteristic radiographic anomalies of the feet. The condition is inherited as an autosomal dominant trait with high penetrance and variable expressivity. Six different mutations in the fibroblast growth factor receptor 2 have been identified in patients with the clinical diagnosis of JWS. Jabs et al. [1994: Nat Genet 8:275-279] identified an Ala344Gly substitution in two branches of the family in which the clinical syndrome was originally described. This is the only publication to document this mutation in a family with the clinical diagnosis of JWS. In this study, we have identified a previously unrecognized branch of the original family with individuals that meet the clinical criteria for the diagnosis of JWS. We demonstrate that a mutation that produces the Ala344Gly substitution is present in affected members. This family illustrates the widely variable expression of the mutation, including a novel phenotype in the proband with a leg-length discrepancy and unilateral absence of the fifth digital ray in her right foot. We identify the clinical and detailed radiographic features of each affected individual and offer considerations when making the diagnosis of JWS.

Acrocephalosyndactylia↗
PubMed2001

Inhibition of apoptosis: a potential mechanism for syndromic craniosynostosis.

The biologic pathogenesis of syndromic craniosynostosis remains unknown. The purpose of this investigation was to determine whether specific biologic differences exist between normal calvarial osteoblasts and osteoblasts derived from patients with syndromic craniosynostosis. This study (1) examined the apoptotic rate and cell cycle of osteoblasts derived from patients with syndromic craniosynostosis, and (2) investigated for the presence of soluble factors released from syndrome-derived osteoblasts. Osteoblast cell lines were established from calvarial specimens of patients with clinically diagnosed syndromic synostosis and from normal controls. A co-culture technique was used to investigate for the presence of elaborated soluble factors. Apoptotic rate and cell cycle analyses were performed by using flow cytometry after staining with annexin V-fluorescein isothiocyanate and propidiumiodide, respectively. The apoptotic rate was significantly reduced in syndrome-derived osteoblasts as compared with control osteoblasts. Control osteoblasts co-cultured with syndromic osteoblasts demonstrated a dramatic reduction in their apoptotic rate as compared with those co-cultured with control osteoblasts. These results indicate that osteoblasts derived from patients with syndromic craniosynostosis display a lower apoptotic rate, a normal DNA synthetic rate, and the capability to reduce the apoptotic rate in normal calvarial osteoblasts through the elaboration of soluble factors.

Apoptosis↗
PubMed2000

Mapping of a gene for severe pediatric gastroesophageal reflux to chromosome 13q14.

CONTEXT: Gastroesophageal reflux (GER) has not previously been widely regarded as a hereditary disease. A few reports have suggested, however, that a genetic component may contribute to the incidence of GER, especially in its severe or chronic forms. OBJECTIVE: To identify a genetic locus that cosegregates with a severe pediatric GER phenotype in families with multiple affected members. DESIGN: A genome-wide scan of families affected by severe pediatric GER using polymorphic microsatellite markers spaced at an average of 8 centimorgans (cM), followed by haplotyping and by pairwise and multipoint linkage analyses. SETTING: General US community, with research performed in a university tertiary care hospital. SUBJECTS: Affected and unaffected family members from 5 families having multiple individuals affected by severe pediatric GER, identified through a patient support group. MAIN OUTCOME MEASURES: Determination of inheritance patterns and linkage of a genetic locus with the severe pediatric GER phenotype by logarithm-of-odds (lod) score analysis, considering a lod score of 3 or greater as evidence of linkage. RESULTS: In these families, severe pediatric GER followed an autosomal dominant hereditary pattern with high penetrance. A gene for severe pediatric GER was mapped to a 13-cM region on chromosome 13q between microsatellite markers D13S171 and D13S263. A maximum multifamily 2-point lod score of 5.58 and a maximum multifamily multipoint lod score of 7.15 were obtained for marker D13S1253 at map position 35 cM when presumptively affected persons were modeled as unknown (a maximum multipoint score of 4.88 was obtained when presumptively affected persons were modeled as unaffected). CONCLUSION: These data suggest that a gene for severe pediatric GER maps to chromosome 13q14. JAMA. 2000;284:325-334

Child↗
PubMed2000

Up-regulation of prostaglandin EP4 receptor messenger RNA in fetal rabbit skin wound.

BACKGROUND: Scar formation and subglottic stenosis often cause health problems in surgical otolaryngology. However, fetal wounds demonstrate scarless healing. The underlying mechanism remains poorly understood. We isolated differentially expressed genes by comparison between nonwounded with wounded skin of fetal and adult rabbits. METHODS: Skin incisional wounds were made in fetal (21 to 23 days' gestation) and adult rabbits. Nonwounded and wounded skin were harvested 12 hours after surgery. Total RNA was extracted. By means of messenger RNA differential display, differentially expressed complementary DNA fragments were isolated, cloned, and sequenced. The expressed transcripts were verified by reverse RNA dot blot and semiquantitative reverse transcription and polymerase chain reaction. RESULTS: One complementary DNA tag that was induced in fetal skin wounds and repressed in adult skin wounds was isolated. The sequence of this complementary DNA (352 base pairs) encodes the messenger RNA for the E-prostanoid (EP) 4 receptor for prostaglandin E(2) (PGE(2)). The truly differential expression of the transcript was confirmed. In normal skin, the EP4 receptor messenger RNA levels were higher in adults than in fetuses. Twelve hours after wounding, the EP4 receptor transcript was remarkably induced in fetal skin wounds but repressed in adult skin wounds. CONCLUSIONS: Our study demonstrates the differential expression of the EP4 receptor messenger RNA in fetal and adult skin before and 12 hours after wounding. Our results suggest that prostaglandin E(2) is involved in the differential cellular responses and in the regulation of the intracellular signal transduction through its binding to EP4 receptor during fetal wound repair.

Animals↗
PubMed2000

Refined localization of a gene for pediatric gastroesophageal reflux makes HTR2A an unlikely candidate gene.

Our objective in this study was to determine whether mutations in the gene for the 5-hydroxytryptamine receptor 2A (HTR2A) cause the autosomal dominant form of severe pediatric gastroesophageal reflux (GER), which we had previously mapped to a 21-cM region at chromosome 13q14. Direct sequencing of the HTR2A gene was carried out on DNA from affected and unaffected members of families with severe pediatric GER displaying genetic linkage to the HTR2A locus. In addition, we performed high-resolution linkage mapping within the GER gene region using additional polymorphic markers closely linked to HTR2A. Several previously reported polymorphisms in the HTR2A gene were identified in three families affected with GER. In addition, we identified a novel polymorphism at nucleotide -1273 in the HTR2A promoter. No mutant allele cosegregated exclusively with the GER phenotype in any family. Linkage analysis using additional polymorphic markers narrowed the region of the GER gene to a 9 cM interval between markers D13S263 and CAGR1, formally excluding HTR2A as a candidate gene. In conclusion, sequence analysis of HTR2A and linkage analysis argue against mutations in HTR2A being a cause of severe pediatric GER.

Child↗
PubMed2000

RNA differential display of scarless wound healing in fetal rabbit indicates downregulation of a CCT chaperonin subunit and upregulation of a glycophorin-like gene transcript.

BACKGROUND/PURPOSE: Scars form as wounds heal in adult organisms. In addition to disrupting cosmetic appearance, scar tissue can cause significant morbidity, and even death if it blocks vital organ function. Previous work has established that fetal wounds, especially in early to midgestation, can heal without scarring. Because such inherent physiological mechanisms ultimately are under genetic control, a study was initiated to elucidate the differences in gene expression that produce scarless wound healing in the mammalian fetus but scarring in postnatal wounds. Reverse transcription polymerase chain reaction (RT-PCR) differential display (DD) was used to detect differentially expressed mRNA transcripts in a rabbit model of wound healing. METHODS: Adult and 21-day fetal full-thickness rabbit skin specimens from wounded and unwounded sites were harvested 12 hours postwounding. RNA extracted from the tissue was used as a template in DD reactions using anchoring and random primers to generate tissue-specific gene expression fingerprints. The over 2,000 resulting amplimers (gene transcripts) were screened for differential expression among the 4 types of specimens: fetal control (unwounded), fetal wound, adult control, and adult wound. Selected bands distinctly upregulated or downregulated in fetal wound lanes on the DD gels were excised, and the cDNA was extracted, reamplified, cloned into vectors, and sequenced. DD results were confirmed by limiting-dilution RT-PCR using sequence-specific primers. RESULTS: Differential display (DD) showed 22 amplimers that were significantly upregulated in all fetal wound samples as compared with little or no expression in fetal control, adult control, or adult wound tissues. Conversely, 5 transcripts were downregulated in the fetal wound specimens but highly expressed in the 3 comparison tissues. Reamplification of selected transcripts by PCR, followed by cloning and DNA sequencing, yielded 7 distinct sequences, each representing a gene expressed differently in fetal wound than in the other 3 tissues. A transcript that was downregulated in fetal wound showed very high sequence homology to part of the human gene for the eta subunit of the hetero-oligomeric particle CCT (the chaperonin containing T-complex polypeptide 1 or TCP-1). An upregulated amplimer showed significant DNA sequence homology to glycophorins A and B. One sequence was identified as 28S rRNA. The remaining 4 candidate sequences showed no significant homology to known genes, but 1 had high homology to expressed sequence tags of unknown function. CONCLUSIONS: With careful experimental design and proper controls and verifications, differential display of RNA expression is a potentially powerful method of finding genes that specifically regulate a particular physiological process such as fetal wound healing. No a priori knowledge of what genes might be involved, or why, is necessary. This study indicates that downregulation of a gene that codes for a chaperonin subunit and upregulation of several other genes may be involved in the striking scarless character of wound healing in the mammalian fetus. Results suggest the hypothesis that downregulation of the CCT chaperonin in fetal wound may inhibit the formation of myofibroblasts, a cell type that correlates highly with scarring in postnatal wound healing, by preventing the folding of sufficient alpha-smooth muscle actin to form the stress fibers characteristic of these cells.

Amino Acid Sequence↗
PubMed1999

Genomic organization of the human fibroblast growth factor receptor 2 (FGFR2) gene and comparative analysis of the human FGFR gene family.

The human fibroblast growth factor receptor (FGFR) genes play important roles in normal vertebrate development. Mutations in the human FGFR2 gene have been associated with many craniosynostotic syndromes and malformations, including Crouzon, Pfeiffer, Apert, Jackson-Weiss, Beare-Stevenson cutis gyrata, and Antley-Bixler syndromes, and Kleeblaatschadel (cloverleaf skull) deformity. The mutations identified to date are concentrated in the previously characterized region of FGFR2 that codes for the extracellular IgIII domain of the receptor protein. The search for mutations in other regions of the gene, however, has been hindered by lack of knowledge of the genomic structure. Using a combination of genomic library screening, long-range PCR, and genomic walking, we have characterized the genomic structure of nearly the entire human FGFR2 gene, including a delineation of the organization and size of all introns and exons and determination of the DNA sequences at the intron/exon boundaries. Comparative analysis of the human FGFR gene family reveals that the genomic organization of the FGFRs is relatively conserved. Moreover, alignment of the amino acid sequences shows that the four corresponding proteins share 46% identity overall, with up to 70% identity between individual pairs of FGFR proteins. However, the FGFR2 gene contains an additional exon not found in other members of the family, and it also has much larger intronic sequences throughout the gene. Remarkable similarities in genomic organization, intron/exon boundaries, and intron sizes are found between the human and mouse FGFR2 genes. Knowledge gained from this study of the human FGFR2 gene structure may prove useful in future screening studies designed to find additional mutations associated with craniosynostotic syndromes, and in understanding the molecular and cell biology of this receptor family.

Alternative Splicing↗
PubMed1999

Development of a simplex polymerase chain reaction-based assay for the detection of Neisseria meningitidis.

BACKGROUND: This study was undertaken to develop a sensitive and specific polymerase chain reaction (PCR)-based assay for Neisseria meningitidis and Neisseria gonorrhoeae that could ultimately be incorporated into a multiplex assay designed to screen cerebrospinal fluid (CSF) for a panel of pyogenic bacterial species associated with bacterial meningitis. METHODS: N.meningitidis-specific primers were designed from porA gene sequences with the aid of a commercial software program and were used to develop and validate a clinical assay using a liquid hybridization-gel retardation detection system. The analytic sensitivity of the assay was determined using CSF spiked with N. meningitidis and comparing the PCR-based results with culture. RESULTS: Analytic sensitivity experiments showed the assay's limit of detection to be 100 fg purified input target DNA and 0.0125 colony-forming units of N. meningitidis spiked into CSF. Specificity experiments showed the assay could detect all strains of N. meningitidis and N. gonorrhoeae tested, but did not support amplification of the commensal neisserial species or a panel of other human bacterial pathogens. CONCLUSIONS: This PCR-based assay for pathogenic neisserial species is sensitive and specific and suitable for incorporation into a multiplex assay for the clinical differentiation of aseptic and septic meningitis.

Bacterial Proteins↗
PubMed1999

Fine mapping of the split-hand/split-foot locus (SHFM3) at 10q24: evidence for anticipation and segregation distortion.

Split-hand/split-foot malformation (SHFM, ectrodactyly, or lobster-claw deformity) is a human limb malformation characterized by aberrant development of central digital rays with absence of fingers and toes, a deep median cleft, and fusion of remaining digits. SHFM is clinically heterogeneous, presenting both in an isolated form and in combination with additional abnormalities affecting the tibia and/or other organ systems, including the genitourinary, craniofacial, and ectodermal structures. Three SHFM disease loci have been genetically mapped to chromosomes 7q21 (SHFM1), Xq26 (SHFM2), and 10q24 (SHFM3). We mapped data from a large Turkish family with isolated SHFM to chromosome 10q24 and have narrowed the SHFM3 region from 9 cM to an approximately 2-cM critical interval between genetic markers D10S1147 and D10S1240. In several instances we found evidence for a more severe phenotype in offspring of a mildly affected parent, suggesting anticipation. Finally, data from this family, combined with those from six other pedigrees, mapped to 10q24, demonstrate biased transmission of SHFM3 alleles from affected fathers to offspring. The degree of this segregation distortion is obvious in male offspring and is possibly of the same magnitude for female offspring.

Chromosome Mapping↗
PubMed1998

Evolution of human immunodeficiency virus type 1 envelope sequences in infected individuals with differing disease progression profiles.

Sequence variation displayed by the human immunodeficiency virus type 1 (HIV-1) has been proposed to be linked to the pathogenesis of acquired immunodeficiency syndrome (AIDS). To assess viral evolution during the course of infection, we evaluated sequence variability in the env variable domains in four HIV-1-infected individuals exhibiting differing profiles of CD4+ T cell decline when followed from seroconversion until the development of AIDS or loss of followup. Proviral sequences encoding the V3-V5 region of gp 120 were obtained following PCR amplification of peripheral blood mononuclear cell DNA and cloning. Virus in each patient was relatively homogeneous early in infection and then diverged with time, more consistently at its nonsynonymous sites. Just prior to or coincident with a rapid decline in CD4+ T cell numbers, sequences were found with basic amino acid substitutions clustered within and downstream of the gp 120 V3 domain. Within the constraints of the current data set, we conclude that the virus appears to continually accumulate changes in its amino acid sequences well into the time of marked CD4+ T cell decline.

Amino Acid Sequence↗
PubMed1998

Evidence of bacterial metabolic activity in culture-negative otitis media with effusion.

CONTEXT: Otitis media with effusion (OME) can lead to significant hearing loss in children. Although previous studies have shown that bacterial DNA is present in a significant percentage of effusions sterile by culture, whether the DNA represents viable organisms or "fossilized remains" is unknown. OBJECTIVE: To determine if bacterial messenger RNA (mRNA), as detected by a reverse transcriptase-polymerase chain reaction (RT-PCR)-based assay, is present in chronic pediatric middle ear effusions that contain bacterial DNA but are sterile by standard cultural methods. Bacterial mRNAs have a half-life measured in seconds to minutes; therefore, detection of bacteria-specific mRNAs would be evidence that metabolically active organisms are present. DESIGN: Blinded comparative study. PATIENTS: A total of 93 effusions from pediatric outpatients seen for myringotomy and tube placement for chronic (>3 months) OME (median age of children, 17 months). SETTING: Tertiary care pediatric hospital. MAIN OUTCOME MEASURES: Percentage of positive test results for RT-PCR-based assays compared with culture for Haemophilus influenzae and concordance between RT-PCR and PCR-based findings for bacterial nucleic acids. RESULTS: Eleven (11.8%) of the 93 specimens tested positive by culture, PCR, and RT-PCR for H influenzae. A total of 29 specimens (31.2%) were positive by PCR but negative by culture for H influenzae. All 29 specimens were positive by RT-PCR for H influenzae-specific mRNA. CONCLUSIONS: The RT-PCR-based assay system can detect the presence of bacterial mRNA in a significant percentage of culturally sterile middle ear effusions, establishing the presence of viable, metabolically active, intact organisms in some culture-negative OME.

Biofilms↗
PubMed1998

Linkage and association between inflammatory bowel disease and a locus on chromosome 12.

Genetic epidemiological studies have shown that genetic factors are important in the pathogenesis of the idiopathic inflammatory bowel diseases (IBD), Crohn disease (CD), and ulcerative colitis (UC). A genome screen in the United Kingdom found linkage of IBD to a 41-cM region of chromosome 12, surrounding D12S83. We aimed to replicate this linkage and to narrow the region of interest. Nonparametric linkage analyses at microsatellites surrounding D12S83 were performed in 122 North American Caucasian families containing 208 genotyped IBD-affected relative pairs. Transmission/disequilibrium tests (TDTs) were also performed. We confirmed that IBD is linked to chromosome 12 (peak GENEHUNTER-PLUS LOD* score 2.76 [P = .00016] between D12S1724 and D12S90). The evidence for linkage is contributed by both the group of CD-affected relative pairs (peak GENEHUNTER-PLUS LOD* score 1.79 [P = .0021] between D12S1724 and D12S90) and the group of UC-affected relative pairs (peak GENEHUNTER-PLUS LOD* score 1.82 [P = .0019] at D12S335). The TDT is positive at the D12S83 locus (global chi2 = 16.41, 6 df, P = .012). In conclusion, we have independently confirmed linkage of IBD to the chromosome 12 region that we investigated. A positive TDT at D12S83 suggests that we have greatly narrowed the chromosome 12 region that contains an IBD locus.

Chromosomes, Human, Pair 12↗
PubMed1998

Lack of R117H mutation in the cationic trypsinogen gene in patients with tropical pancreatitis from Bangladesh.

The etiology of nonalcoholic chronic pancreatitis, occurring in tropical regions, is unknown. Although environmental factors may play a role in its pathogenesis, a specific genetic predisposition may be necessary. The genetic mutation responsible for hereditary pancreatitis was described recently. Unlike in patients with hereditary pancreatitis, we found a lack of the R117H mutation in the cationic trypsinogen gene in all patients with tropical pancreatitis from Bangladesh.

Adolescent↗
PubMed1998

Blinded multiplex PCR analyses of middle ear and nasopharyngeal fluids from chinchilla models of single- and mixed-pathogen-induced otitis media.

Multiplex PCR analyses for both bacterial and viral pathogens were conducted in a blinded manner on 33 archival specimens, of known culture status, procured from chinchilla models of both single- and mixed-pathogen-induced otitis media and from a pediatric patient. These specimens had been maintained at -70 degrees C for up to 6 years. Experimental specimens evaluated included middle-ear effusions, nasopharyngeal lavage fluids and middle-ear lavage fluids from animals which were immunologically naive, sham-immunized or actively immunized with nontypeable Haemophilus influenzae antigens. Sampling times used ranged from the day of bacterial or viral challenge to 42 days after challenge. Initial PCR analyses of the 33 specimens matched the traditional culture data in 24 instances (73%), correctly identifying nontypeable H. influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, or adenovirus as the causative agent. A PCR-positive signal for the microbe(s) inoculated was also obtained in four animal model specimens (12%) which were culture negative. One of two culture-negative human effusions was also PCR positive. Thus, overall, results obtained by blinded PCR were 85% concordant with traditional culture methods or correctly indicated the specific pathogen introduced in four specimens that were sterile. In no instance was a false-positive signal obtained for any of the five etiologic agents being evaluated. We conclude that the multiplex PCR analyses are rapid and accurate methodologies when they are used to retrospectively evaluate diverse archival specimens of limited volume from experimental models of otitis media.

Adenoviridae↗
PubMed1998

Correlation between presence of viable bacteria and presence of endotoxin in middle-ear effusions.

The presence of endotoxin (detected by the Limulus amebocyte lysate assay) was compared to the presence of viable Haemophilus influenzae and Moraxella catarrhalis (detected by PCR) in 106 middle-ear effusions from pediatric patients with chronic otitis media. Endotoxin was found in 81 of the 106 specimens. Of these 81 specimens, 66 (81.5%) also tested positive for one or both of the gram-negative bacteria H. influenzae and M. catarrhalis. The data suggest that viable gram-negative bacteria, detectable by PCR but often undetectable by culture, may be the source of endotoxin in middle-ear effusions.

Adolescent↗
PubMed1998

Genetic diversity among strains of Moraxella catarrhalis: analysis using multiple DNA probes and a single-locus PCR-restriction fragment length polymorphism method.

Moraxella (Branhamella) catarrhalis, a causative agent of otitis media, sinusitis, and exacerbation of bronchitis, has acquired widespread ability to produce beta-lactamase and can be nosocomially transmitted. The typing methods used in epidemiological analyses of M. catarrhalis are not optimal for genetic analyses. Two methods, a multiple-locus Southern blot (SB) method and a single-locus PCR-restriction fragment length polymorphism (RFLP) method, were developed and used to assess genetic diversity and potential clinical and geographic relationships in M. catarrhalis. Nine randomly cloned M. catarrhalis DNA fragments were used as probes of SBs containing DNA from 54 geographically and clinically diverse strains. For comparison, a PCR-RFLP method was developed as a quick, inexpensive, and discriminating alternative. A highly variable 3.7-kb genomic region (M46) was cloned and sequenced, and 3.5 kb of the cloned DNA was targeted for PCR amplification. DNAs from the 54 strains were subjected to PCR-RFLP. SB analysis distinguished all strains that had no apparent epidemiological linkage (40 of 54), and PCR-RFLP distinguished fewer strains (21 of 54). Epidemiologically linked strains appeared genetically identical by both methods. PCR-RFLP was compared to pulsed-field gel electrophoresis (PFGE) for 8 of the 54 strains and 23 additional strains. PCR-RFLP distinguished fewer strains than PFGE typing (16 of 31 versus 20 of 31 strains), but PCR-RFLP was more useful for inferring interstrain relatedness. Separate cluster analyses of multilocus SB and single locus PCR-RFLP data showed high genetic diversity within and across geographic locations and clinical presentations. The resultant dendrograms were not entirely concordant, but both methods often gave similar strain clusters at the terminal branches. High genetic diversity, nonconcordance of cluster analyses from different genetic loci, and shared genotypes among epidemiologically linked strains support a hypothesis of high recombination relative to spread of clones. Single-locus PCR-RFLP may be suitable for short-term epidemiological studies, but the SB data demonstrate that greater strain discrimination may be obtained by sampling variation at multiple genomic sites.

Adult↗