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Biomedical subjects

I Roberts

Publications and source records attributed to I Roberts.

At least 37 records · Page 2Linked to original sources
PubMed2001

Simultaneous fetal cell identification and diagnosis by epsilon-globin chain immunophenotyping and chromosomal fluorescence in situ hybridization.

Isolating fetal erythroblasts from maternal blood offers a promising noninvasive alternative for prenatal diagnosis. The current immunoenzymatic methods of identifying fetal cells from background maternal cells postenrichment by labeling gamma-globin are problematic. They are nonspecific because maternal cells may produce gamma-globin, give poor hybridization efficiencies with chromosomal fluorescence in situ hybridization (FISH), and do not permit simultaneous visualization of the fetal cell identifier and the FISH signal. We describe a novel technique that allows simultaneous visualization of fetal erythroblast morphology, chromosomal FISH, and epsilon-globin labeled with AMCA (7-amino-4-methylcoumarin-3-acetic acid). AMCA was chosen as the fluorescent label to circumvent the problem of heme autofluorescence because the mean difference in relative fluorescence intensity between fetal erythroblasts stained positive for antiglobin antibody and autofluorescence of unstained cells was greater with AMCA (mean 43.2; 95% confidence interval [CI], 34.6-51.9; SD = 14.0) as the reporting label compared with fluorescein isothiocyanate (mean 24.2; 95% CI, 16.4-31.9; SD = 12.4) or phycoerythrin (mean 9.8; 95% CI, 4.8-14.8; SD = 8.0). Median FISH hybridization efficiency was 97%, comparable to the 98% (n = 5 paired samples) using Carnoy fixative. One epsilon-positive fetal erythroblast was identified among 10(5) maternal nucleated cells in 6 paired mixture experiments of fetal erythroblasts in maternal blood (P <.001). Male epsilon-positive fetal erythroblasts were clearly distinguishable from adult female epsilon-negative erythroblasts, with no false positives (n = 1000). The frequency of fetal erythroblasts expressing epsilon-globin declines linearly from 7 to 14 weeks' gestation (y = -15.8 x + 230.8; R(2) = 0.8; P <.001). We describe a rapid and accurate method to detect simultaneously fetal erythroblast morphology, intracytoplasmic epsilon-globin, and nuclear FISH. (Blood. 2001;98:554-557)

Adult↗
PubMed2001

Association of polymorphisms in the human interferon-gamma and interleukin-10 gene with acute and chronic kidney transplant outcome: the cytokine effect on transplantation.

BACKGROUND: Our group has previously described five different size alleles of an interferon (IFN)-gamma microsatellite. Analyzing this polymorphism, this study correlated high IFN-gamma production with a 12 CA repeat allele (allele 2). Further, our group has described interleukin (IL)-10 polymorphism defining in vitro high and low IL-10 producer status. METHODS: Samples from 88 of 115 consecutive cadaveric renal transplants were used to define polymorphism of both IFN-gamma and IL-10. Patients were separated into high and low genotypes based on the previously reported association between certain genotypes and in vitro production. Graft survival, acute rejection, and serum creatinine at 5 years were analyzed for comparison between groups. RESULTS: The genotype associated with high IFN-gamma production was found in 70 patients. The incidence of acute rejection was 54.3% in the high IFN-gamma genotype group, compared with 44.4% in the low IFN-gamma group. Requirement for antithymocyte globulin therapy was greater in the high IFN-gamma group (odds ratio [OR]=2.5). Among HLA-DR-mismatched patients, IFN-gamma genotype was more strongly associated with rejection (OR=2.86). In the cyclosporine monotherapy subgroup, patients with high IFN-gamma genotype had a 61% incidence of rejection compared with only 20% in the low IFN-gamma genotype patients (OR=3.06). Graft survival was similar between the two groups. When the analysis was controlled for the presence of delayed graft function, 40.5% of the high IFN-gamma genotype patients had serum creatinine levels above 200 micromol/L compared with only 14.3% of the low IFN-gamma genotype recipients at 5 years after transplantation (P=0.05). The high IL-10 genotype was shown to be associated with better graft function at 5 years (75 vs. 50%, P=0.09). CONCLUSION: In this study we have shown that high producer genotype for IFN-gamma may have an influence on acute rejection of kidney transplants, particularly in patients on cyclosporine monotherapy. It is also associated with worse long-term graft function. On the contrary high IL-10 production may have a long-term protective effect.

Acute Disease↗
PubMed2001

Early genetic events in HPV immortalised keratinocytes.

Cancer of the uterine cervix (CaCx) is the second most common cancer in women worldwide. More than 99% of all cervical cancers contain high-risk human papillomaviruses (HPVs), with type 16 predominating. HPV infection alone is not sufficient for neoplastic progression; the HPV-infected cell must undergo additional genetic changes. Cytogenetic analysis of CaCx has been limited due to difficulties in obtaining good-quality banded chromosome preparations. Oncogenic HPVs immortalise primary genital keratinocytes in vitro, and evidence suggests that the molecular genetic and cytogenetic abnormalities observed in HPV immortalised cells reflect the in vivo changes. Therefore, these lines represent suitable models for HPV-induced carcinogenesis. We have used both spectral karyotyping (SKY) and multiplex-FISH (M-FISH) analysis to identify karyotypic changes in HPV-16 immortalised keratinocyte cell lines and established CaCx lines. SKY and M-FISH identified chromosomal abnormalities in all cell lines examined, with a translocation of chromosome 10 or i(10q) occurring in 9 of the 12 cell lines investigated. Further studies with chromosome 10 band-specific probes identified the translocation event as involving 10q with the breakpoint at 10p11.2 in some cell lines or 10q11.2 in others. The pericentric region of chromosome 10 is known to contain duplicated sequences flanking the centromeric satellites. The duplicated sequences contain many zinc finger transcription factor encoding genes and disruption of these in HPV immortalised cell lines may alter the transcription with consequences for both cellular and viral gene expression.

Aneuploidy↗
PubMed2001

Timing and volume of fluid administration for patients with bleeding following trauma.

BACKGROUND: Treatment of haemorrhagic shock involves maintaining blood pressure and tissue perfusion until bleeding is controlled. Different resuscitation strategies have been used to maintain the blood pressure in trauma patients until bleeding is controlled. However, while maintaining blood pressure may prevent shock, it may worsen bleeding. OBJECTIVES: To assess the effects of early versus delayed, and larger versus smaller volume of fluid administration in trauma patients with bleeding. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register, the specialised register of the Injuries Group, MEDLINE, EMBASE, the National Research Register and the Science Citation Index. We checked reference lists of identified articles and contacted authors and experts in the field. SELECTION CRITERIA: Randomised trials of the timing and volume of intravenous fluid administration in trauma patients with bleeding. Trials in which different types of intravenous fluid were compared were excluded. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed trial quality. MAIN RESULTS: We did not combine the results quantitatively because the interventions and patient populations were so diverse. Early versus delayed fluid administration: Three trials reported mortality and two coagulation data. In the first trial (n=598) relative risk (RR) for death with early fluid administration was 1.26 (95% confidence interval of 1.00-1.58). The weighted mean differences (WMD) for prothrombin time and partial thromboplastin time were 2.7 (95% CI 0.9-4.5) and 4.3 (95% CI 1.74-6.9) seconds respectively. In the second trial (n=50) RR for death with early blood transfusion was 5.4 (95% CI 0.3-107.1). The WMD for partial thromboplastin time was 7.0 (95% CI 6.0-8.0) seconds. In the third trial (n=1309) RR for death with early fluid administration was 1.06 (95% CI 0.77-1.47). Larger versus smaller volume of fluid administration: Three trials reported mortality and one coagulation data. In the first trial (n=36) RR for death with a larger volume of fluid resuscitation was 0.80 (95% CI 0.28-22.29). Prothrombin time and Partial thromboplastin time were 14.8 and 47.3 seconds in those who received a larger volume of fluid as compared to 13.9 and 35.1 seconds in the comparison group. In the second trial (n=99) RR for death with a high (100 mm Hg) compared to low (70 mm Hg) systolic blood pressure resuscitation target was 1.02 (95% CI 0.27-3.85). In the third trial (n=25) there were no deaths. REVIEWER'S CONCLUSIONS: We found no evidence from randomised controlled trials to support early or larger volume of intravenous fluid administration in uncontrolled haemorrhage. There is continuing uncertainty about the best fluid administration strategy in bleeding trauma patients. Further randomised controlled trials are needed to establish the most effective fluid resuscitation strategy.

Hemorrhage↗
PubMed2001

Spinal immobilisation for trauma patients.

BACKGROUND: Spinal immobilisation involves the use of a number of devices and strategies to stabilise the spinal column after injury and thus prevent spinal cord damage. The practice is widely recommended and widely used in trauma patients with suspected spinal cord injury in the pre-hospital setting. OBJECTIVES: To quantify the effect of different methods of spinal immobilisation (including immobilisation versus no immobilisation) on mortality, neurological disability, spinal stability and adverse effects in trauma patients. SEARCH STRATEGY: We searched the Cochrane Controlled Trial Register (CCTR), the specialised register of the Cochrane Injuries Group, MEDLINE, EMBASE, CINAHL, PubMed and the National Research Register. We checked reference lists of all articles and contacted experts in the field to identify eligible trials. Manufacturers of spinal immobilisation devices were also contacted for information. SELECTION CRITERIA: Randomised controlled trials comparing spinal immobilisation strategies in trauma patients with suspected spinal cord injury. Trials in healthy volunteers were excluded. DATA COLLECTION AND ANALYSIS: Two reviewers independently applied eligibility criteria to trial reports and extracted data. MAIN RESULTS: We found no randomised controlled trials of spinal immobilisation strategies in trauma patients. REVIEWER'S CONCLUSIONS: We did not find any randomised controlled trials that met the inclusion criteria. The effect of spinal immobilisation on mortality, neurological injury, spinal stability and adverse effects in trauma patients remains uncertain. Because airway obstruction is a major cause of preventable death in trauma patients, and spinal immobilisation, particularly of the cervical spine, can contribute to airway compromise, the possibility that immobilisation may increase mortality and morbidity cannot be excluded. Large prospective studies are needed to validate the decision criteria for spinal immobilisation in trauma patients with high risk of spinal injury. Randomised controlled trials in trauma patients are required to establish the relative effectiveness of alternative strategies for spinal immobilisation.

Humans↗
PubMed2001

Advanced trauma life support training for ambulance crews.

BACKGROUND: There is an increasing global burden of disease from injuries. Models of trauma care initially developed in high-income countries are also being adopted in low and middle-income countries (LMIC). Amongst these ambulance crews with Advanced Life Support (ALS) training are being promoted in LMIC as a strategy for improving outcomes for victims of trauma. However there is controversy as to the effectiveness of this health service intervention, and the evidence has yet to be rigorously appraised. OBJECTIVES: To quantify the effectiveness of ambulance crews with ALS training versus crews with any other level of training in reducing mortality and morbidity in trauma patients. SEARCH STRATEGY: We searched the Cochrane Controlled Trial Register (CCTR), the specialised register of the Cochrane Injuries Group, MEDLINE, EMBASE, CINAHL, PubMed and the National Research Register. We checked references of background papers and contacted authors to identify additional published or unpublished data. SELECTION CRITERIA: Randomised controlled trials, quasi-randomised controlled trials and controlled before-and-after studies comparing effectiveness of ambulance crews with ALS training versus crews with any other levels of training in reducing mortality and morbidity in trauma patients. Studies which compared crews staffed by physicians versus others were excluded. DATA COLLECTION AND ANALYSIS: Two reviewers independently applied eligibility criteria to trial reports for inclusion and extracted data. MAIN RESULTS: We found one randomised controlled trial, which included 16 trauma cases. However, outcome data were added to the main non-randomised cohort in the analysis, and data on these 16 cases are not yet available. REVIEWER'S CONCLUSIONS: In the absence of evidence of the effectiveness of advanced life support, strong argument could be made that it should not be promoted outside the context of a properly concealed and otherwise rigorously conducted randomised controlled trial.

Controlled Clinical Trials as Topic↗
PubMed2001

Characterization of four CD18 mutants in leucocyte adhesion deficient (LAD) patients with differential capacities to support expression and function of the CD11/CD18 integrins LFA-1, Mac-1 and p150,95.

Leucocyte adhesion deficiency (LAD) is a hereditary disorder caused by mutations in the CD18 (beta2 integrin) gene. Four missense mutations have been identified in three patients. CD18(A270V) supports, at a diminished level, CD11b/CD18 (Mac-1, alphaMbeta2 integrin) and CD11c/CD18 (p150,95, alphaXbeta2 integrin) expression and function but not CD11a/CD18 (LFA-1, alphaLbeta2 integrin) expression. Conversely, CD18(A341P) supports a limited level of expression and function of CD11a/CD18, but not of the other two CD11/CD18 antigens. CD18(C590R) and CD18(R593C) show a decreasing capacity to associate with the CD11a, CD11c and CD11b subunits. Transfectants expressing the CD11a/CD18 with the C590R and R593C mutations are more adhesive than transfectants expressing wild-type LFA-1, and express the reporter epitope of the monoclonal antibody 24 constitutively. Thus, the four mutations affect CD18 differently in its capacities to support CD11/CD18 expression and adhesion. These results not only provide a biochemical account for the clinical diversity of patients with leucocyte adhesion deficiency, but also offer novel insights into the structural basis of interaction between the alpha and beta subunits, which is an integral component in our understanding of integrin-mediated adhesion and its regulation.

Alleles↗
PubMed2001

Physical and psychological effects of injury. Data from the 1958 British birth cohort study.

BACKGROUND: There is only scant evidence for the long-term health effects of road traffic injuries. We therefore assessed the extent to which motor vehicle driver injuries influence limiting long-standing illness and psychological distress using data from a nationwide study (the 1958 British birth cohort) in early adulthood. METHODS: Information was obtained on driver injuries occurring between ages 23 and 33 years and limiting illnesses and psychological distress at age 33 years. The risks of injury-related adverse consequences were derived using logistic regression and expressed as odds ratios (ORs) and 95% confidence intervals. RESULTS: A single injury was associated with limiting illness (OR = 2.01 and 95% CI: 1.38-2.94). The association between a single injury and psychological distress was strong for a recent injury occurring between ages 30 and 33 years (OR = 1.86 and 95% CI: 1.24-2.81), but not for injuries occurring earlier on. The population attributable fraction for limiting illness with one injury was 3.8% (range 1.7-5.3%) and with two or more injuries was 1.0% (range 0.5-1.3%). After controlling for potential confounding factors the corresponding figures were 4.2% (range 2.2-5.6%) and 1.1% (range 0.5-1.3%) respectively. CONCLUSIONS: Driver injuries are associated with a substantial increase in disability and, also in the short term, with increases in psychological distress. These results highlight the need for identifying effective strategies for the prevention of road traffic injuries as well as more effective approaches for rehabilitation of the injured.

Accidents, Traffic↗
PubMed2001

Helicobacter pylori-related gastric outlet obstruction: is there a role for medical treatment?

The role of Helicobacter pylori in the pathogenesis of duodenal and gastric ulcer and ulcer recurrence is widely known. Bleeding, perforation, and gastric outlet obstruction represent the most serious, potentially life-threatening complications of ulcer disease. At present, the effect of H. pylori eradication on complicated ulcer disease has not been fully established. Case reports exist on the resolution of gastric outlet obstruction after eradication of H. pylori. We report the first case of H. pylori-related gastric outlet obstruction successfully treated with parenteral antibiotics.

Gastric Outlet Obstruction↗
PubMed2001

Gallstone pancreatitis: a community teaching hospital experience.

GOALS: The current study reviews the Bridgeport Hospital experience with gallstone pancreatitis (GP) and examines its incidence by race and gender. STUDY: Consecutive patients admitted with acute pancreatitis between October 1994 and October 1996 were identified using discharge diagnosis codes. Demographics and clinical information were abstracted. Patients were categorized as having definite GP, probable GP, and non-GP using the available information. RESULTS: One hundred twenty-three patients met criteria for acute pancreatitis. Of these, 40 met the criteria for definite GP; 14, probable; and 69, non-GP. The estimated incidence for acute pancreatitis was 45 per 100,000 person-years (95% CI = 41-58 per 100,000 person-years) for definite GP and was 20 per 100,000 person-years (95% CI = 14-25 per 100,000 person-years) for probably GP. Patients with definite or probable GP were predominantly white or Hispanic women and tended to be older. Only 16% of pancreatitis in black patients was associated with gallstones. Elevated alanine aminotransferase (ALT > 120 U/L) was highly specific (97%) in predicting GP, with a positive likelihood ratio of 18.3. Abdominal ultrasound was the most widely used imaging study. Complication rates were low. There was only one intrahospital death. CONCLUSIONS: The incidence of acute pancreatitis requiring hospitalization at our community hospital in 1994-1996 was 45 (95% CI = 41-58) per 100,000 person-years. Forty percent of these cases were associated with gallstones. Gallstone pancreatitis was more common among the elderly women and the white (white, non-Hispanic) population. Elevated ALT was highly specific in the prediction of GP.

Acute Disease↗
PubMed2001

Molecular cytogenetic analysis consistently identifies translocations involving chromosomes 1, 2 and 15 in five embryonal rhabdomyosarcoma cell lines and a PAX-FOXO1A fusion gene negative alveolar rhabdomyosarcoma cell line.

Rhabdomyosarcoma in children is a "small round blue cell tumour" that displays skeletal muscle differentiation. Two main histological variants are recognised, alveolar (ARMS) and embryonal (ERMS) rhabdomyosarcoma. Whereas consistent chromosome translocations characteristic of ARMS have been reported, no such cytogenetic abnormality has yet been described in ERMS. We have used multiple colour chromosome painting to obtain composite karyotypes for five ERMS cell lines and one PAX-FOXO1A fusion gene negative ARMS. The cell lines were assessed by spectral karyotyping (SKY), tailored multi-fluorophore fluorescence in situ hybridisation (M-FISH) using series of seven colour paint sets generated to examine specific abnormalities, and comparative genomic hybridisation (CGH). This approach enabled us to obtain karyotypes of the cell lines in greater detail than previously possible. Several recurring cytogenetic abnormalities were demonstrated, including translocations involving chromosomes 1 and 15 and chromosomes 2 and 15, in 4/6 and 2/6 cell lines respectively. All six cell lines demonstrated abnormalities of chromosome 15. Translocations between chromosomes 1 and 15 have previously been recorded in two primary cases of ERMS by conventional cytogenetics. Analysis of the translocation breakpoints may suggest mechanisms of ERMS tumourigenesis and may enable the development of novel approaches to the clinical management of this tumour.

Child↗