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G Ling

Publications and source records attributed to G Ling.

At least 19 recordsLinked to original sources
PubMed2007

HLA-A, -B, -C, -DRB1 allele and haplotype frequencies in an African American population.

Sequence-based typing was used to identify human leukocyte antigen (HLA)-A, -B, -C, and -DRB1 alleles from 564 consecutively recruited African American volunteers for an unrelated hematopoietic stem cell registry. The number of known alleles identified at each locus was 42 for HLA-A, HLA-B 67, HLA-C 33, and HLA-DRB1 44. Six novel alleles (A*260104, A*7411, Cw*0813, Cw*1608, Cw*1704, and DRB1*130502) not observed in the initial sequence-specific oligonucleotide probe testing were characterized. The action of balancing selection, shaping more 'even' than expected allele frequency distributions, was inferred for all four loci and significantly so for the HLA-A and DRB1 loci. Two-, three-, and four-locus haplotypes were estimated using the expectation maximization algorithm. Comparisons with other populations from Africa and Europe suggest that the degree of European admixture in the African American population described here is lower than that in other African American populations previously reported, although HLA-A:B haplotype frequencies similar to those in previous studies of African American individuals were also noted.

Black or African American↗
PubMed2006

Strategies for evaluating B*18 allelic diversity by sequence-based typing applied to studies of a population from Singapore and African-Americans.

Strategies to resolve B*18 alleles which carry a deletion in intron 1 close to the 5' end of exon 2 relative to other HLA-B alleles or a null allele mutation in exon 1 and to resolve ambiguities among allele combinations including B*18 are described. B*18 allele frequencies from volunteer donors recruited for two hematopoietic stem cell registries show the presence of two alleles, B*180101 and B*1802, in a population from Singapore and only B*180101 in African-Americans.

Black or African American↗
PubMed2004

Exclusion of galectin 9 as a candidate gene for hyperuricosuria in the Dalmatian dog.

All Dalmatian dogs have an inherited defect in purine metabolism leading to high levels of uric acid excretion in their urine (hyperuricosuria) rather than allantoin, the normal end product of purine metabolism in all other breeds of dog. Transplantation experiments have demonstrated that the defect is intrinsic to the liver and not the kidney. Uricase, the enzyme involved in the breakdown of urate into allantoin, has been shown to function in Dalmatian liver cells. Therefore, candidate genes for this defect include transporters of urate, a salt of uric acid, across cell membranes. We excluded one such urate transporter candidate, galectin 9, using a Dalmatian x Pointer backcross in which hyperuricosuria was segregating.

Alleles↗
PubMed2003

Treatment with the snail peptide CGX-1007 reduces DNA damage and alters gene expression of c-fos and bcl-2 following focal ischemic brain injury in rats.

Delayed cell death following ischemic brain injury has been linked to alterations in gene expression. In this study we have evaluated the upregulation of several genes associated with delayed cell death (c-fos, bax, and bcl-2) during the initial 24 h of transient middle cerebral artery occlusion (MCAo) in the rat and the effects of postinjury treatment with the NR2B subunit specific NMDA receptor antagonist CGX-1007 (Conantokin-G, Con-G). C-fos mRNA levels peaked at 1 h postinjury in both cortical and subcortical ischemic brain regions (30-fold increase), remained elevated at 4 h and returned to within normal, preinjury levels 24 h postinjury. The increase in mRNA levels correlated to increased protein expression in the entire ipsilateral hemisphere at 1 h. Regions of necrosis at 4 h were void of C-Fos immunoreactivity with continued upregulation in surrounding regions. At 24 h, loss of C-Fos staining was observed in the injured hemisphere except for sustained increases along the border of the infarct and in the cingulate cortex of vehicle treated rats. CGX-1007 treatment reduced c-fos expression throughout the infarct region by up to 50%. No significant differences were measured in either bcl-2 or bax mRNA expression between treatment groups. However, at 24 h postinjury CGX-1007 treatment was associated with an increase in Bcl-2 immunoreactivity that correlated to a reduction in DNA fragmentation. In conclusion, CGX-1007 effectively attenuated gene expression associated with delayed cell death as related to a neuroprotective relief of cerebral ischemia.

Animals↗
PubMed2001

Activation of the NPTA element of the CYP2A3 gene by NFI-A2, a nasal mucosa-selective nuclear factor 1 isoform.

The aim of this study was to determine whether the NPTA element of the olfactory mucosa-predominant CYP2A3 gene can be activated by NFI-A2, a recently identified member of the nuclear factor 1 family of transcription factors. Isoform-specific RNA-PCR confirmed that NFI-A2 is mainly expressed in rat olfactory mucosa. A full-length NFI-A2 cDNA was isolated from a cDNA library of rat olfactory mucosa and was used for preparation of a construct encoding a fusion protein of NFI-A2 with the yeast GAL4 activation domain. Expression of the fusion protein in yeast was detected with an antibody to NFI-A. The fusion protein activated the expression of a LacZ reporter gene in yeast one-hybrid assays with a reporter construct containing the NPTA element, but not with other constructs lacking the NPTA element. These findings suggest that NFI-A2 may be involved in the tissue-selective transcriptional activation of the CYP2A3 gene in the olfactory mucosa.

Amino Acid Sequence↗
PubMed2001

PATCHED and p53 gene alterations in sporadic and hereditary basal cell cancer.

It is widely accepted that disruption of the hedgehog-patched pathway is a key event in development of basal cell cancer. In addition to patched gene alterations, p53 gene mutations are also frequent in basal cell cancer. We determined loss of heterozygosity in the patched and p53 loci as well as sequencing the p53 gene in tumors both from sporadic and hereditary cases. A total of 70 microdissected samples from tumor and adjacent skin were subjected to PCR followed by fragment analysis and DNA sequencing. We found allelic loss in the patched locus in 6/8 sporadic basal cell cancer and 17/19 hereditary tumors. All sporadic and 7/20 hereditary tumors showed p53 gene mutations. Loss of heterozygosity in the p53 locus was rare in both groups. The p53 mutations detected in hereditary tumors included rare single nucleotide deletions and unusual double-base substitutions compared to the typical ultraviolet light induced missense mutations found in sporadic tumors. Careful microdissection of individual tumors revealed genetically linked subclones with different p53 and/or patched genotype providing an insight on time sequence of genetic events. The high frequency and co-existence of genetic alterations in the patched and p53 genes suggest that both these genes are important in the development of basal cell cancer.

Adult↗
PubMed2001

Rituximab using a thrice weekly dosing schedule in B-cell chronic lymphocytic leukemia and small lymphocytic lymphoma demonstrates clinical activity and acceptable toxicity.

PURPOSE: Rituximab has been reported to have little activity in small lymphocytic lymphoma (SLL)/chronic lymphocytic leukemia (CLL) and to be associated with significant infusion-related toxicity. This study sought to decrease the initial toxicity and optimize the pharmacokinetics with an alternative treatment schedule. PATIENTS AND METHODS: Thirty three patients with SLL/CLL received dose 1 of rituximab (100 mg) over 4 hours. In cohort I (n = 3; 250 mg/m(2)) and cohort II (n = 7; 375 mg/m(2)) rituximab was administered on day 3 and thereafter three times weekly for 4 weeks using a standard administration schedule. Cohort III (n = 23; 375 mg/m(2)) administered rituximab similar to cohort II for the first two treatments and then over 1 hour thereafter. RESULTS: A total of 33 CLL/SLL patients were enrolled; only one patient discontinued therapy because of infusion-related toxicity. Thirteen patients developed transient hypoxemia, hypotension, or dyspnea that were associated with significant changes in baseline interleukin-6, interleukin-8, tumor necrosis factor alpha, and interferon gamma compared with those not experiencing such reactions. Infusion-related toxicity occurred more commonly in older (median age 73 v 62 years; P =.02) patients with no other pretreatment clinical or laboratory features predicting occurrence of these events. The overall response rate was 45% (3% CR, 42% PR; 95% CI 28% to 64%). Median response duration for these 15 patients was 10 months (95% CI, 6.8-13.2; range, 3 to 17+). CONCLUSION: Rituximab administered thrice weekly for 4 weeks demonstrates clinical efficacy and acceptable toxicity. Initial infusion-related events seem to be cytokine mediated and resolve by the third infusion making rapid administration possible. Future combination studies of rituximab with other therapies in CLL seem warranted.

Aged↗
PubMed2001

Persistent p53 mutations in single cells from normal human skin.

Epidermal clones of p53-mutated keratinocytes are abundant in chronically sun-exposed skin and may play an important role in early development of skin cancer. Advanced laser capture microdissection enables genetic analysis of targeted cells from tissue sections without contamination from neighboring cells. In this study p53 gene mutations were characterized in single cells from normal, chronically sun-exposed skin. Biopsies were obtained from skin subjected to daily summer sun and skin totally protected from the sun by blue denim fabric. Using laser capture microdissection, 172 single-cell samples were retrieved from four biopsies and analyzed using single-cell polymerase chain reaction and direct DNA sequencing. A total of 14 different mutations were identified in 26 of 99 keratinocytes from which the p53 gene could be amplified. Mutations displayed a typical UV signature and were detected in both scattered keratinocytes and in a small cluster of p53-immunoreactive keratinocytes. This minute epidermal p53 clone had a diameter of 10 to 15 basal cells. Two missense mutations were found in all layers of epidermis within the p53 clone. The presented data show that p53 mutations are common in normal skin and that a clone of keratinocytes with a mutated p53 gene prevailed despite 2 months of total protection from ultraviolet light.

Adult↗
PubMed2001

Epidermal p53 response and repair of thymine dimers in human skin after a single dose of ultraviolet radiation: effects of photoprotection.

A cellular p53 response, DNA repair enzymes and melanin pigmentation are important strategies utilized by skin keratinocytes against impairment caused by ultraviolet radiation (UVR). In this study a double-immunofluorescence technique was used to investigate UVR-induced thymine dimers and p53 protein simultaneously. Four healthy volunteers were irradiated on both sides of their buttock skin with a single dose of solar-simulating UVR. One side was pretreated with a topical sunscreen. Biopsies from different time-points were immunostained for visualization of thymine dimers, p53 and proliferation. One single physiological dose of UVR generated widespread formation of thymine dimers throughout the epidermis 4h after irradiation. The level of thymine dimers decreased over time and was followed by a p53 response in the same cells. A late proliferative response was also found. The formation of thymine dimers, the p53 response and the late proliferative response were partially blocked by topical sunscreen. Large inter-individual differences in the kinetics of thymine dimer formation and repair as well as in the p53 response were evident in both sunscreen-protected and unprotected skin.

Adult↗
PubMed2001

Utility of routine serial computed tomography for blunt intracranial injury.

BACKGROUND: To determine the utility of routine serial head computed tomography (H-CT) for predicting need for invasive neurosurgical intervention in patients with blunt intracranial injuries (BICI). METHODS: Patients treated at a Level I trauma center with BICI over a 4-year period were reviewed. RESULTS: Of the 4,273 blunt trauma patients evaluated, 9.7% (415/4,273) were diagnosed as having BICI. Invasive intervention (craniotomy, ICP monitoring, ventriculostomy, or angiogram) was performed in 41.2% (171/415) of patients with BICI. Of these, 94.7% (162/171) had the procedure performed as a result of the initial H-CT. The remaining 5.3% (9/171) had the intervention performed as a result of a subsequent H-CT. Serial H-CT documented worsening of BICI in 32.3% (64/198) of the patients, but only those who had significant corresponding clinical deterioration had an invasive procedure as a result. CONCLUSION: In patients with an unchanged or normal neurologic exam, a routine serial H-CT did not influence subsequent invasive neurosurgical intervention.

Adolescent↗
PubMed2000

Analysis of p53 mutations in single cells obtained from histological tissue sections.

We have previously reported on direct sequence analysis of the p53 gene in laser-dissected single cells from tissue sections, where each allele of two fragments (exons 7 and 8) could be accurately analyzed in only 14% of the cells due to the high frequency of exon and allele dropout. Here in an effort to minimize this problem, we have investigated various approaches for sample preparation and gene amplification. By pinpointing some critical steps in the procedure, we could increase the number of investigated exons and substantially improve the genetic analysis of single cells obtained from histochemically stained frozen tissue sections. The biggest improvement was achieved by minimizing DNA degradation using EDTA as a nuclease inhibitor in all sample preparation steps. Efforts to increase primer annealing, by increasing the concentration of template and primers, in addition to prolonging the annealing and extension times, also improved the amplification efficiency. With these measures we can now amplify six individual exons of the p53 gene (exons 4-9) in 70% of the cells and in 50% of these cells both alleles are amplified. This allows application of the method in various investigations such as within the field of tumor pathology.

Alleles↗
PubMed2000

Human neutrophil activation and increased adhesion by various resuscitation fluids.

OBJECTIVE: To determine whether activated neutrophils play a major role in secondary tissue injury after resuscitation in trauma. We hypothesized that human neutrophil activation and adhesion vary, depending on the type and amount of resuscitation fluid used. SETTING: University-based research facility. SUBJECTS: Ten healthy adult volunteers. DESIGN: Whole blood from volunteers was serially diluted in polypropylene tubes with various resuscitation fluids. Fluids tested were phosphate-buffered saline, normal saline, lactated Ringer's solution, dextran, hespan, 5% human albumin, 25% human albumin, 3.5% hypertonic saline, and 7.5% hypertonic saline. Neutrophil activation (intracellular oxidative burst activity with dichlorofluorescin diacetate staining) and adhesion (integrin cell surface expression of CD18) were measured with flow cytometry (fluorescence-activated cell sorting). Blood was diluted with hypertonic saline by controlling for sodium content equal to normal saline. dose-related increase in neutrophil oxidative burst activity as the result of dilution followed with crystalloid fluids and artificial colloids (dextran and hespan). The increase was 12-18 x baseline at the 75% dilution. The increase with 5% human albumin was only 2.2 x baseline, and 25% albumin did not demonstrate any increased intracellular activity. A similar significant increase in the neutrophil adhesion expression (CD18) occurred with artificial colloids (p<.05) and, to a lesser extent, with crystalloids, but not with albumin. Hypertonic saline caused a decrease in CD18 cell surface expression. CONCLUSIONS: This study suggests that the neutrophil activation and adhesion may vary, depending on the type of resuscitative fluid used. All artificial resuscitative fluids may not be similar or innocuous, as demonstrated by the dose-related increase in neutrophil activation and adhesion.

Adult↗
PubMed2000

Induced hypothermia during emergency department thoracotomy: an animal model.

BACKGROUND: Induced hypothermia is used clinically to prevent ischemic injury during elective procedures. We present an animal model of asanguinous hypothermic (10 degrees C) circulatory arrest, induced through a left anterior lateral thoracotomy after exsanguinating uncontrolled hemorrhage. METHODS: Through a left anterior thoracotomy, 26 swine (45-70 kg) sustained a laceration of the descending thoracic aorta, producing exsanguinating uncontrolled hemorrhage. After 5 minutes of severe hypotension (systolic BP <20 mm Hg), a 22 French Foley catheter was directed cephalad through the enlarged aortic wound. A solution (containing 42.5 mmol/L K+ and precooled to 1 degrees C) was infused to arrest/preserve the heart and brain. A second 24 French Foley catheter was then directed caudally through the same wound. The right atrium was opened to drain the venous system. The animal was cooled with a cardiopulmonary bypass pump (>5L/min) through the Foley catheters. Once 10 degree C was reached, a cannula was placed to the aortic root and the aortic laceration repaired. The animal was maintained at 10 degree C for a total of 90 minutes. Before the rewarming process, the circulation was rinsed with a solution containing normal levels of electrolytes followed by infusion of whole blood. Rewarming was performed by maintaining a 10-degree gradient on the heat exchanger. The first 16 animals were used in nonsurvival experiments to develop the technique and to record dural temperatures and electroencephalogram tracings. The last 10 animals were used to determine long-term survival and neurologic outcome. Group I: seven animals were kept at < 10 degrees C with flows less than 2L/min. Group II: three animals underwent 20, 30, and 40 minutes of no flow once they were cooled to 10 degrees C. After 6 weeks of survival and neurologic examinations, the brains were fixed for histologic evaluations. RESULTS: The average time to cool the head to 18 degrees C and 10 degrees C was 6 minutes and 12 minutes, respectively. The hematocrit fell below 2% by the end of the cooling period. A total of 7 of the 10 animals from the long-term study survived. Group I: five of seven animals survived. Four of the survivors had no appreciable neurologic deficits, were fully functional at 6 weeks, and had no evidence of histologic injury. One of the five survivors in this group had moderate neurologic disability. Of the two animals that died, one died from air embolism from the i.v. line. The second death was in an animal for which maximal cooling to 2.7 degrees C was attempted. Group II: The first two animals that had "no flow" for 20 and 30 minutes were fully functional and had normal neurologic examinations. However, the second animal was found to have brain injury on histologic examination. The last animal in this group died of accidental extubation during recovery. CONCLUSION: Induction of hypothermic arrest through the chest after exsanguination is possible. The further development of this technique may provide an extended state of "suspended animation" to allow for repairs of hemorrhaging injuries in trauma patients who require emergency department thoracotomy.

Animals↗
PubMed2000

Evidence of commonality between canine and human extraintestinal pathogenic Escherichia coli strains that express papG allele III.

Although dogs have been proposed as carriers of extraintestinal pathogenic Escherichia coli (ExPEC) with infectious potential for humans, presumed host species-specific differences between canine and human ExPEC strains have cast doubt on this hypothesis. The recent discovery that allele III of papG (the P fimbrial adhesin gene) predominates among human cystitis isolates and confers an adherence phenotype resembling that of canine ExPEC prompted the present reevaluation of the canine-human ExPEC connection. Sixteen paired pap-positive urine and rectal E. coli isolates from dogs with urinary tract infection were studied. papG (adhesin) and papA (pilin) allele type, agglutination phenotypes, virulence factor genotypes, and randomly amplified polymorphic DNA and pulsed-field gel electrophoresis fingerprints were analyzed and compared with those of human ExPEC controls. The 16 canine strains contained predominantly papG allele III. Agglutination phenotypes segregated strictly according to papG allele status and were homogeneous among strains with the same papG allele profile irrespective of their human versus canine origin. Canine and human PapG variant III peptide sequences were highly homologous, without host species-specific differences. The most prevalent canine papA allele was F48, a novel variant recently identified among human urosepsis isolates. In addition to pap, human ExPEC-associated virulence genes detected among the canine strains included sfa/focDE, sfaS, fyuA, hlyA, cnf1, cdtB, kpsMT-II and -III, rfc, traT, ompT, and a marker for a pathogenicity-associated island from archetypal human ExPEC strain CFT073. Molecular fingerprinting confirmed the fecal origin of all but one canine urine isolate and showed one pair of O6 canine urine and fecal isolates to be extremely similar to an O6 human urosepsis isolate with which they shared all other genotypic and phenotypic characteristics analyzed. These data demonstrate that canine ExPEC strains are similar to, and in some instances essentially indistinguishable from, human ExPEC strains, which implicates dogs and their feces as potential reservoirs of E. coli with infectious potential for humans.

Adhesins, Escherichia coli↗
PubMed2000

[The study of beta-fibrinogen gene - 455 G/A, - 148 C/T, 448 G/A polymorphisms and their association with plasma fibrinogen levels].

OBJECTIVE: To analyze the frequency of beta-fibrinogen (beta-Fg) gene - 455 G/A, - 148 C/T, 448 G/A polymorphisms and their association with plasma fibrinogen levels in Han nationality in Guangdong Chinese. METHODS: The beta-Fg gene - 455 G/A, - 148 C/T, 448 G/A polymorphisms of 156 individuals were analyzed by restriction fragment length polymorphism (RFLP). Plasma fibrinogen levels were determined by turbidimetry. RESULTS: The frequencies of A(- 455), T(- 148) and A(448) allele were 0.276, 0.285 and 0.272, respectively. There were strong linkages of G(- 455), C(- 148) and G(448), and of A(- 455), T(- 148) and A(448), the correspondence was more than 97%. The plasma fibrinogen levels in the presence and absence of A(- 455) allele were (3.13 +/- 0.74) g/L and (2.89 +/- 0.57) g/L (P < 0.05); of T(- 148) allele were (3.12 +/- 0.73) g/L and (2.89 +/- 0.58) g/L (P < 0.05); and of A(448) were (3.13 +/- 0.74) g/L and (2.89 +/- 0.57) g/L (P < 0.05), respectively. The plasma fibrinogen levels of the three polymorphisms with the mutant gene are significantly higher than that in the wild type. CONCLUSION: The three polymorphisms loci are strong linkage disequilibrium. It suggests that beta-Fg gene - 455 G/A, - 148 C/T, 448 G/A polymorphisms are associated with plasma fibrinogen levels.

Adult↗
PubMed1999

A comprehensive guide for the recognition and classification of distinct stages of hair follicle morphogenesis.

Numerous spontaneous and experimentally induced mouse mutations develop a hair phenotype, which is often associated with more or less discrete abnormalities in hair follicle development. In order to recognize these, it is critically important to be able to determine and to classify accurately the major stages of normal murine hair follicle morphogenesis. As an aid, we propose a pragmatic and comprehensive guide, modified after previous suggestions by Hardy, and provide a list of easily recognizable classification criteria, illustrated by representative micrographs. Basic and more advanced criteria are distinguished, the former being applicable to all mouse strains and requiring only simple histologic stains (hematoxylin and eosin, Giemsa, periodic acid Schiff, alkaline phosphatase activity), the latter serving as auxiliary criteria, which require a pigmented mouse strain (like C57BL/6J) or immunohistochemistry (interleukin-1 receptor type I, transforming growth factor-beta receptor type II). In addition, we present simplified, computer-generated schematic drawings for the standardized recording and reporting of gene and antigen expression patterns during hair follicle development. This classification aid serves as a basic introduction into the field of hair follicle morphogenesis, aims at standardizing the presentation of related hair research data, and should become a useful tool when screening new mouse mutants for discrete abnormalities of hair follicle morphogenesis (compared with the respective wild type) in a highly reproducible, easily applicable, and quantifiable manner.

Animals↗