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Biomedical subjects

J Murphy

Publications and source records attributed to J Murphy.

At least 37 records · Page 2Linked to original sources

Coronin involved in phagocytosis: dynamics of particle-induced relocalization visualized by a green fluorescent protein Tag.

Coronin is a protein involved in cell locomotion and cytokinesis of Dictyostelium discoideum. Here we show that coronin is strongly enriched in phagocytic cups formed in response to particle attachment. A fusion of coronin with green fluorescent protein (GFP) accumulates in the cups within less than 1 min upon attachment of a particle and is gradually released from the phagosome within 1 min after engulfment is completed. Phagocytic cup formation competes with leading edge formation and can be interrupted at any stage. When the cup regresses, coronin dissociates from the site of accumulation. TRITC-labeled yeast cells have been used to assay phagocytosis quantitatively in wild-type and coronin-null cells. In the mutant, the rate of uptake is reduced to about one third, which shows that coronin contributes to the efficiency of phagocytosis to about the same extent as it improves the speed of cell locomotion.

Actinin

Risk factors and cofactors for human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in Jamaica.

Human T-cell lymphotropic virus type I (HTLV-I) has been etiologically associated with a neurologic syndrome called HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) as well as with adult T-cell leukemia/lymphoma. The authors sought to quantify the risk in Jamaica of HAM/TSP associated with HTLV-I infection and cofactors associated with this disease among infected individuals. Between 1988 and 1989, prevalent and incident HAM/TSP patients and controls with other neurologic diseases were enrolled in a retrospective study. A second control group was composed of HTLV-I-seropositive, asymptomatic carriers in Jamaica, ascertained in a separate study conducted in 1988. Although HTLV-I seropositivity was not a component of the case definition for HAM/TSP, all 43 HAM/TSP patients were HTLV-I seropositive compared with two (4.0%) of the controls with other neurologic diseases. Given HTLV-I seropositivity, one cofactor associated with the risk of HAM/TSP was young age at initial heterosexual confidence interval 1.29-12.46 for individuals aged < or = 15; odds ratio = 4.26, 95% confidence interval 1.41-12.90 for individuals aged 16-17 years at initial intercourse). Among individuals who reported this early age at initial sexual intercourse, an increased risk of HAM/TSP was associated with having reported more than five lifetime sexual partners (odds ratio = 2.88, 95% confidence interval 0.90-8.70). Neither an early age at initial sexual intercourse or the number of lifetime sexual partners was a risk factor for adult T-cell leukemia/lymphoma. These data support the hypothesis that HAM/TSP is associated with sexually acquired HTLV-I infection, whereas adult T-cell leukemia/lymphoma is not.

Adolescent

Evidence for a shift from a type I lymphocyte pattern with HIV disease progression. Hemophilia Growth and Development Study.

Whether a shift from a type I (cell mediated) immune profile occurs with progressive HIV-related immune dysfunction is a matter of heated debate. We analyzed data for 333 HIV antibody-positive (HIV+) and -negative (HIV-) hemophilic children/adolescents, to examine whether the relationships among immunologic parameters and vaccine-related serology supported a shift with advancing HIV infection. In stepwise logistic regression analysis of HIV+ children's data, anergy to a panel of delayed hypersensitivity skin test antigens was positively associated with serum immunoglobulin A (IgA) levels (p = 0.012) and CD8+ cell counts (p = 0.021) and negatively associated with CD4+ cell counts (p = 0.002). Modeling supported anergy as a positive correlate of log IgA level (p = 0.046) and CD4+ lymphocyte count as a negative correlate, for HIV+ participants only (p < 0.0001). For mumps, the proportion of vaccinated HIV+ participants with protective IgG antibody titers was higher among those with CD4+ lymphocyte counts < 200 cells/mm3 (p = 0.058). For HIV+ participants < 14 years of age, this same trend was seen for measles and rubella, but was not seen in any age group for bacterial vaccine antigens. The intercorrelations among skin test anergy, CD4+ lymphocyte counts, serum IgA levels, and viral vaccine antigen-related serologic titers for HIV+ participants are consistent with an association between progressive HIV-related immune dysfunction and a predominance of type II (humoral immunity) or Type 0 (mixed immunity), relative to type I, lymphocyte profiles.

Adolescent

Binding in vitro of phosphotyrosine-containing proteins to pp60c-src SH2 domain does not correlate with CEF transformation.

We have previously described pp60c-src SH2 mutants that are host-range-dependent for cell transformation; most of these mutants can transform CEF cells but not NIH3T3 cells, and other transform NIH3T3 cells more efficiently than CEF (Hirai and Varmus, 1990c). In an attempt to understand the molecular basis of these phenotypes, we analysed the ability of mutant SH2 domains in GST fusion proteins to bind to tyrosine phosphorylated proteins in lysates from CEF and NIH3T3 cells. The relative affinity of mutated versions of the SH2 domain for phosphotyrosine-containing proteins from CEF and NIH3T3 cells was compared with the relative ability of the mutant Src proteins to transform the two cell types. While the affinity of the SH2 domain for phosphotyrosine-containing proteins was closely correlated with transformation in NIH3T3 cells, there was no correlation between phosphotyrosine binding and transformation of CEF cells, and none of the host range mutant SH2 domains showed significant differences in their ability to bind phosphotyrosine-containing proteins from lysates from either cell type. In addition, the SH3 domain was shown to augment the capacity of mutant SH2 domain to bind phosphotyrosine-containing proteins.

3T3 Cells

Bleomycin therapy for cystic hygroma.

Intralesional bleomycin injection was used as sclerosant therapy for sixteen patients with cystic hygroma. An excellent (complete clinical resolution) response was obtained in seven (44%) patients, a good (> 50% response) result in seven (44%), and a poor or no response in two (12%). Minor transient side effects (fever, vomiting, cellulitis, skin discoloration) were seen in six patients, and there were no serious side effects. The results suggest that bleomycin intralesional sclerosant is effective therapy for cystic hygroma, with response rates comparable to those of surgical removal, but with the advantage of avoiding inadvertent nerve damage and scarring.

Bleomycin

Effect of acute and chronic caffeine use on the cerebrovascular, cardiovascular and hormonal responses to orthostasis in healthy volunteers.

1. The effects of acute and chronic caffeine ingestion on supine- and tilt- (60 min at 70 degrees) induced changes in middle cerebral artery velocity (Vmca), heart rate, blood pressure and counter-regulatory hormone levels (catecholamines, growth hormone and cortisol) were studied in nine healthy volunteers. A double-blind, placebo-controlled design was used to study acute effects followed by an open study after 6 days of chronic caffeine use. 2. In the supine position, acute ingestion of caffeine (250 mg) was associated with a fall in Vmca [-11 cm/s, point estimate of difference versus placebo (95% confidence interval: -17, -6) cm/s, P < 0.001] and a rise in mean arterial pressure [+4 (1, 6) mmHg, P < 0.01] and plasma adrenaline levels [+138 (53, 223) pmol/l, P < 0.01]. After chronic caffeine use, the pressor and adrenaline responses, but not the drop in Vmca, were significantly attenuated. 3. On tilting to 70 degrees the fall in Vmca was greater with placebo than after acute caffeine ingestion [-10 (-14, -15) cm/s, P < 0.01], whereas increments (above supine values) in heart rate, mean arterial pressure and hormone levels were unchanged by caffeine. In contrast, the adrenaline [+126 (29, 282) pmol/l, P < 0.01] and noradrenaline [+0.6, 0.9) nmol/l, P < 0.05] responses to tilting were augmented after acute caffeine ingestion. Chronic caffeine supplementation did not alter the fall in Vmca associated with tilting, but significantly attenuated the adrenaline response (P < 0.01 compared with the acute study). 4. Acute caffeine ingestion and orthostasis are both associated with a reduction in Vmca and a rise in mean arterial pressure and adrenaline levels. The acute effects of caffeine on mean arterial pressure and adrenaline but not on Vmca are lost with sustained caffeine intake. These results suggest dissociation between the development of central and peripheral tolerance after chronic caffeine use.

Adult

Lack of beta 1 integrin gene in embryonic stem cells affects morphology, adhesion, and migration but not integration into the inner cell mass of blastocysts.

A gene trap-type targeting vector was designed to inactivate the beta 1 integrin gene in embryonic stem (ES) cells. Using this vector more than 50% of the ES cell clones acquired a disruption in the beta 1 integrin gene and a single clone was mutated in both alleles. The homozygous mutant did not produce beta 1 integrin mRNA or protein, while alpha 3, alpha 5, and alpha 6 integrin subunits were transcribed but not detectable on the cell surface. Heterozygous mutants showed reduced beta 1 expression and surface localization of alpha/beta 1 heterodimers. The alpha V subunit expression was not impaired on any of the mutants. Homozygous ES cell mutants lacked adhesiveness for laminin and fibronectin but not for vitronectin and showed a reduced association with a fibroblast feeder layer. Furthermore, they did not migrate towards chemoattractants in fibroblast medium. None of these functions were impaired in heterozygous mutants. Scanning electron microscopy revealed that homozygous cells showed fewer cell-cell junctions and had many microvilli not usually found on wild type and heterozygous cells. This profound change in cell shape is not associated with gross alterations in the expression and distribution of cytoskeletal components. Unexpectedly, microinjection into blastocysts demonstrated full integration of homozygous and heterozygous mutants into the inner cell mass. This will allow studies of the consequences of beta 1 integrin deficiency in several in vivo situations.

Animals

Significance of intra-abdominal extraluminal air detected by CT scan in blunt abdominal trauma.

The purpose of this study was to determine the frequency and significance of computed tomographic (CT) scan-detected pneumoperitoneum in blunt abdominal trauma. We retrospectively reviewed 118 consecutive CT scans of the abdomen in blunt abdominal trauma patients (mean Injury Severity Score 24), performed at our Regional Trauma Unit over a 12-month period. Seven (5.9%) patients had intra-abdominal extraluminal air. None of these seven patients had evidence of bowel perforation at laparotomy (two) or on clinical follow-up (five). All seven had chest tubes in place before the CT scan. None of the seven patients were on mechanical ventilation at the time of CT scan. In the setting of blunt abdominal trauma pneumoperitoneum does not necessarily indicate hollow viscus injury. It frequently is secondary to other etiologies, especially dissection of interstitial air from the chest, as suggested in this study. The decision for laparotomy should be based on a combination of the clinical findings, CT scan results, or other diagnostic tests such as peritoneal lavage.

Abdominal Injuries

A multicopy plasmid of the extremely thermophilic archaeon Sulfolobus effects its transfer to recipients by mating.

A plasmid of 45 kb, designated pNOB8, was found in high copy number in a new heterotrophic Sulfolobus isolate, NOB8H2, from Japan. Dissemination of the plasmid occurred in six cultures of nine different Sulfolobus strains when small amounts of the donor were added. These mixed cultures exhibited a high average copy number of the plasmid, between 20 and 40 per chromosome, and showed a marked growth retardation. Horizontal transfer of pNOB8 was proved by isolating transcipients from mating mixtures via single colonies. In these isolates, the copy number of the plasmid appeared to be subject to a control mechanism. Cell-free filtrates of donor cultures did not transmit the plasmid, and plating of the donor on lawns of recipients did not result in plaque formation, suggesting that the transfer was not mediated by a virus. Rapid formation of cell-to-cell contacts between differently stained donor and recipient partners was demonstrated after the two strains were mixed. Electron microscopic analysis of mating mixtures revealed many cell aggregates made up of 2 to 30 cells and intercellular cytoplasmic bridges connecting two or more cells. Cells that had been transformed with purified plasmid DNA as well as transcipients isolated from mating mixtures were shown to serve as donors for further transmission of pNOB8. The plasmid undergoes extensive genetic variations, since deletions and insertions were frequently observed in plasmid preparations from the donor strain and from mating mixtures.

Cell Aggregation

Carotid Stenosis Index. A new method of measuring internal carotid artery stenosis.

BACKGROUND AND PURPOSE: Current methods of measuring carotid stenosis such as those used in the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) have limitations caused by difficulties in measuring the normal width of the distal internal carotid artery (ICA) or the carotid bulb. METHODS: We developed a new technique, the Carotid Stenosis Index (CSI), based on the known anatomic relationship between the common carotid artery (CCA) and ICA (1.2 x CCA diameter=proximal ICA diameter). The normal ICA diameter can therefore be calculated from direct measurement of the CCA. Three blinded observers evaluated the angiograms of 57 patients (114 carotid arteries), previously screened with duplex ultrasonography, using the NASCET, ECST, and CSI methods. In a subset of 30 patients undergoing carotid endarterectomy, comparison was also made to computerized carotid plaque planimetry. RESULTS: The NASCET method could only be applied correctly in 89% and the ECST method in 95% of cases because of overlying vessels or inadequate views of the distal ICA or carotid bulb. An additional 9% of NASCET cases had a "negative" stenosis, in which the stenosis is wider than the distal ICA. The CSI method was applicable in 99% of cases. Interobserver comparison using ANOVA revealed significant differences using NASCET (P < .0001) and ECST (P <.001) but not CSI (P = NS). NASCET had a sevenfold variation (P < .01) and ECST a twofold variation (P < .01) in results compared with CSI. The intraobserver reliability was 0.87 for NASCET, 0.86 for ECST, and 0.90 for CSI. However, the 95% confidence intervals for an individual measurement by an observer were +/- 30% for NASCET, +/- 19% for ECST, and +/- 15% for CSI. With linear methods of measurement there were significant differences between NASCET and CSI (P < .0001) and ECST (P < .0001) but not between CSI and ECST. A comparison of area derivations of these methods to carotid plaque planimetry revealed significant differences from NASCET (P <.0001) but not ECST, CSI, or duplex methods. A CSI nomogram was created, allowing measurement of both linear and area percent stenosis. CONCLUSIONS: CSI is the most reliable validated method of measuring carotid stenosis, and it correlates with duplex and carotid pathology.

Carotid Artery, Common

Attention deficit hyperactivity disorder and comorbid disorders: issues of overlapping symptoms.

OBJECTIVE: Since some symptoms are shared by both attention deficit hyperactivity disorder (ADHD) and comorbid psychiatric conditions, it is possible that a diagnosis of ADHD is an artifact of the overlapping symptoms. This article focuses on the assessment of the influence of overlapping symptoms on the diagnosis of ADHD. METHOD: Three groups of subjects were studied: a group of clinically referred children and adolescents, a group of nonreferred adults who were the parents of these children and adolescents, and a group of clinically referred adults with ADHD. The authors assessed the extent of symptom overlap between ADHD and the disorders that frequently co-occur with ADHD; major depression, bipolar disorder, and generalized anxiety disorder. To determine the degree to which this symptom overlap influences these diagnoses, each individual was rediagnosed on the basis of two different techniques that corrected for the overlapping symptoms, a subtraction method and a proportion method. RESULTS: The majority of subjects who had both ADHD and a comorbid psychiatric disorder maintained their diagnosis of ADHD when the overlapping symptoms were subtracted. Moreover, when overlapping ADHD symptoms were subtracted, on average, 79% maintained their diagnosis of major depression, 56% maintained their diagnosis of bipolar disorder, and 75% maintained their diagnosis of generalized anxiety disorder. CONCLUSIONS: These findings show that ADHD is not an artifact of symptoms shared with other psychiatric disorders and that the comorbid conditions themselves are not an artifact of overlapping ADHD symptoms.

Adolescent

The role of protein phosphorylation in the assembly of a replication competent nucleus: investigations in Xenopus egg extracts using the cyanobacterial toxin microcystin-LR.

Cell-free extracts of Xenopus eggs support nuclear assembly and DNA replication in vitro. Extracts supplemented with the protein phosphatase inhibitor microcystin-LR displayed various inhibitory effects at different concentrations of the toxin. In the presence of cycloheximide, additions of microcystin did not induce histone H1-kinase activity. Nevertheless, increasing concentrations of microcystin did sequentially prevent DNA replication, nuclear lamina assembly and nuclear envelope assembly. DNA replication was prevented when microcystin was added at 250 nM. Furthermore, this effect could be reversed after the addition of the catalytic sub-unit of protein phosphatase 2A to inhibited extracts. At a concentration of 250 nM microcystin, nuclear membrane assembly, nuclear lamina assembly and nuclear transport all occurred in egg extracts. In addition single-stranded M13 DNA replication was also permitted. However, it appeared that replicase assembly was not completed, since nuclei assembled in microcystin-treated extracts displayed an unusual distribution of proliferating cell nuclear antigen (PCNA). Although PCNA was located at sites that resembled pre-replication foci, this nuclear protein was readily solubilised when nuclei were isolated and extracted sequentially with Triton, nucleases and salts. Despite this, nuclei containing pre-assembled replication forks could synthesise DNA when transferred into microcystin-treated extracts.

Animals

A survey of enteropathogens among United States military personnel during Operation Bright Star '94, in Cairo, Egypt.

Acute gastroenteritis is a potential cause of substantial morbidity in U.S. military personnel during deployment. This study was conducted to evaluate enteric pathogens associated with diarrhea in a U.S. military population on deployment in Cairo, Egypt, during November 1993. Enteric pathogens found to be associated with cases of diarrhea included: enterotoxigenic Escherichia coli (ETEC), 27% (22% heat-stable [ST], 3% heat-labile [LT], and 2% ST/LT producers); Campylobacter spp., 3%; and Salmonella spp. 3%. Other enteric pathogens, namely Shigella, Aeromonas, Plesiomonas, Vibrio spp., Bacillus cereus, and enteric parasites, were not found in any of the 36 patients. Of the 8 patients who were ETEC-positive, three expressed colonization factor antigens (CFA)/II, and two expressed putative colonization factor antigen (PCF) 0159. All of the latter isolates produced ST. ETEC with different surface protein antigens were found to have surface hydrophobicity in the range of 0.2 M to greater than 2.0 M. Plasmid profiles of the ETEC strains showed no correlation with toxin production. In vitro susceptibility testing of the ETEC strain showed that 32% of the strains were resistant to three or more antimicrobial agents, whereas 24% showed 100% susceptibility. The enteropathogens tested were susceptible to norfloxacin, ciprofloxacin, and nalidixic acid, suggesting that the quinolones might be useful for the treatment of diarrheic patients.

Aeromonas

The Jupiter approach to interoperability with healthcare legacy systems.

This paper describes a novel approach to supporting interoperability between autonomous healthcare information systems. The approach, which has been implemented in the Jupiter system, is founded on the development of a formal model of legacy systems that are used as the basis for the definition of a language to support interoperability. Jupiter gives users a uniform, integrated view of heterogeneous, distributed, independent information systems. The target domain of Jupiter is healthcare, although the solution is sufficiently generic to be applicable elsewhere.

Computer Systems

Readability of subject information leaflets for medical research.

AIM: To compare the readability of adult subject information leaflets prepared for medical research projects with the readability scores of a range of New Zealand newspaper editorials and popular magazine articles. METHODS: Of the 134 research projects approved by the Auckland Area Health Board in 1991, 99 were analysed together with nine randomly selected newspaper editorials and nine randomly selected articles from popular magazines. The Flesch reading ease index, the Flesch-Kincaid index and the Gunning fog index were calculated using a computerised grammar checker. RESULTS: Subject information leaflets were easier to read than newspaper editorials but significantly more difficult to read than articles in popular magazines. The Flesch reading ease index showed that information leaflets had a median readability score of 53 compared with magazines which had a score of 67 and newspaper editorials which had a score of 48. The level of secondary school education required to read information leaflets was equivalent to about 2 years or form 4, whereas a level of about form 5 appears to be required to read newspaper editorials and a level of about form 1 for magazine articles. CONCLUSIONS: The readability level of information leaflets prepared for participants in medical research in the Auckland area appears satisfactory and the process for reviewing this component of the research protocol appears consistent and effective. Readability scores may be a useful tool in assessing the overall ease with which written information can be read.

Clinical Trials as Topic

Antiphospholipid antibodies in predicting adverse pregnancy outcome. A prospective study.

OBJECTIVE: To determine if the presence of antiphospholipid antibody (aPL) in healthy pregnant women is associated with adverse pregnancy outcome, including 1) intrauterine fetal loss, 2) maternal pregnancy complications, 3) low birth weight, and 4) low 5-minute Apgar scores. DESIGN: Prospective cohort study in women with normal pregnancies. SETTING: Obstetrics clinic at the University of Colorado Health Sciences Center. PATIENTS: Eligible patients included 451 low-risk, nulliparous pregnant women who came to the obstetrics clinic before 25 weeks gestation; 408 were enrolled and 389 had blood drawn at the first prenatal visit and completed clinical follow-up. MEASUREMENTS: Blood for six aPL measures was drawn at the first prenatal visit and for 239 patients at delivery. RESULTS: Ninety-five patients (24.4%) had elevated aPL levels by one or more measures at the first prenatal visit: 15.8% of the aPL-positive and 6.5% of the aPL-negative patients experienced fetal loss (relative risk, 2.44; 95% CI, 1.29 to 4.62). However, an elevated IgG anticardiolipin antibody level at the first prenatal visit was the only aPL measurement that was significantly associated with fetal loss (relative risk, 3.5; CI, 1.56 to 8.07). Adjustment for confounding variables decreased the relative risk of aPL for fetal loss slightly, but the difference remained statistically significant. Neither a positive aPL result at the initial visit nor a positive result at delivery was associated with maternal complications of pregnancy, low birth weight, or low Apgar scores. CONCLUSIONS: Patients with elevated aPL levels at their initial prenatal visit had an increase in fetal loss but no increase in maternal pregnancy complications, low birth weight, or low Apgar scores. Immunoglobulin G anticardiolipin antibody was the only single test of aPL significantly associated with fetal loss.

Abortion, Spontaneous

Immune and serologic profiles of HIV-infected and noninfected hemophilic children and adolescents. Hemophilia Growth and Development Study Group.

OBJECTIVES: To assess relationships among the effects of HIV on hemophilic children and adolescents' immunologic parameters and vaccine-related serology. METHODS: We analyzed data from extensive baseline immunologic evaluations of 207 HIV antibody-positive (HIV+) and 126 HIV antibody-negative (HIV-) hemophilic children and adolescents. RESULTS: HIV+ and HIV- participants differed significantly in T-lymphocyte subpopulation numbers, immunoglobulin levels, and seroprevalence rates for diphtheria toxoid, measles, and mumps antigens, IgG levels, IgM levels, and serologic titers to vaccine antigens showed little correlation with T-cell parameters. Proportionately more HIV+ participants were nonreactive to each and all of a panel of 7 skin test antigens (71% vs 28% anergic, RR 2.6). The odds of anergy increased 1.6 times for every decline of 200 CD4+ cells/microliters. CONCLUSIONS: HIV had significant, largely independent T- and B-lymphocyte effects on this pediatric cohort.

Adolescent

High-dose methotrexate for gestational trophoblastic disease.

Eighty patients with low-risk and 5 patients with intermediate-risk gestational trophoblastic neoplasia (GTN) (WHO classification) were treated with single-agent high-dose methotrexate with folinic acid rescue (MTX/FAR). By the NCI classification, 65 patients had nonmetastatic GTN, 13 patients had low-risk metastatic GTN, and 7 patients had high-risk metastatic GTN. Seventy-one (84%) patients achieved remission (beta HCG < or = 5 IU/liter) with MTX/FAR, whereas 14 (16%) failed to achieve remission with MTX/FAR alone. All failures were salvaged with second-line therapies. Patients successfully treated with MTX/FAR required a median of 4 courses to achieve remission, and a median of 2 consolidative courses. Factors found predictive of failure with MTX/FAR were pretreatment beta HCG (P = 0.003), prior history of GTN (P < 0.04), and time from termination of antecedent pregnancy to initiation of treatment (P < 0.05). No significant difference was noted between the "success" and "failure" groups with respect to MTX dose or infusion time, the timing and dosage of folinic acid rescue, the number of courses of MTX, or the mean interval between courses. Multivariate analysis revealed that the pretreatment beta HCG (P < 0.01) and short time from termination of antecedent pregnancy to initiation of treatment (P < 0.03) were independently significant for failure. No significant (grade 3/4) hematologic or gastrointestinal toxicity occurred, and no treatment delays or dose reductions were required. This regimen is both effective and well tolerated; however, the theoretical advantages of high-dose methotrexate do not appear to offer any clinical advantage over conventional dose MTX in low- and intermediate-risk GTN.

Biomarkers, Tumor