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J M Carr

Publications and source records attributed to J M Carr.

At least 19 recordsLinked to original sources
PubMed2006

Vif-deficient HIV reverse transcription complexes (RTCs) are subject to structural changes and mutation of RTC-associated reverse transcription products.

Reverse transcription (RTn) in HIV-infected cells occurs in a nucleoprotein complex termed the reverse transcription complex (RTC). RTCs containing RT activity and integrase (IN) were shown to be heterogeneous in size and density on sucrose velocity and equilibrium gradients. WT and Vif-deficient (Deltavif) RTCs produced by infection with virus from permissive cells displayed similar sedimentation characteristics, while RTCs from Deltavif virus produced in non-permissive cells demonstrated a reduction in the major RTC form and more of the RTn products in rapidly sedimenting structures. APOBEC3G derived from virions did not co-sediment with RTCs, but RTCs from Deltavif infections showed elevated levels of mutations in RTn products, consistent with APOBEC3G and other mutational mechanisms. The most mutated transcripts were present within rapidly sedimenting RTCs. Thus, virus without functional vif, produced from non-permissive cells, forms abnormal RTCs that contain increased mutation of RTC-associated RTn products in newly infected target cells.

APOBEC-3G Deaminase↗
PubMed2006

Cellular interactions of virion infectivity factor (Vif) as potential therapeutic targets: APOBEC3G and more?

Vif is an HIV accessory protein whose primary function is to negate the action of APOBEC3G, a naturally occurring cellular inhibitor of HIV replication. Vif acts by binding to APOBEC3G, inducing its protein degradation within infected cells and reducing its levels in progeny virions. Interventions that interfere with the Vif-APOBEC3G interaction, raise intracellular or virion associated levels of APOBEC3G, or reduce intracellular levels of Vif, all could hold promise as potential therapeutic approaches aimed at enhancing the cells innate antiviral activity. Levels of APOBEC3G might be increased or Vif levels decreased, by strategies targeting protein synthesis, protein degradation or cellular localisation and function, and properties of APOBEC3G and Vif relevant to these strategies are discussed. Recent data have suggested that Vif may have other mechanisms of action apart from the above activities against APOBEC3G, including effects against other anti-viral mechanisms independent of APOBEC3G cytidine deaminase activity. In addition to interaction with APOBEC3G, Vif may have other accessory functions, which are discussed in relation to potential therapies that may affect multiple stages of the HIV life cycle. Future development of strategies that combine enhancement of APBOEC3G functional with inhibition of multiple Vif functions may become useful tools for HIV therapy.

APOBEC-3G Deaminase↗
PubMed2001

Effect of deletion and the site of insertion in double copy anti-tat retroviral vectors: viral titres and production of anti-tat mRNA.

In attempts to further develop murine leukemia virus (MLV) based retroviral vectors for gene therapy, we investigated vector production and antisense expression from retroviral constructs with U3 deletions or insertions. Promoter elements in the U3 region of the 3' LTR of the vector pLXSN were deleted and replaced with DNA encoding the HIV anti-tat gene under control of the tRNAmet promoter to produce a double copy self inactivating vector (DC-SIN). DC-SIN constructs were compared to vectors containing the anti-tat cassette inserted at 5 different sites of the U3 region (DC-insertions). Titres of DC-SIN and DC-insertion vectors were similar but approximately 10 fold lower than parental pLXSN. Cells transduced with DC-SIN and DC-insertion vectors all expressed anti-tat mRNA. Transcripts from the MLV-LTR were detected in cells transduced with DC-insertion but not DC-SIN vectors or a vector with the anti-tat cassette between CAAT and TATA boxes of the promoter, indicating inactivation of the viral promoter in the latter vectors. Cells transduced with constructs of either design showed comparable efficacy of protection against HIV challenge. Thus, no U3 insertion site was preferred for virus production. Insertion of a tRNA promoter between CAAT and TATA boxes and the DC-SIN design which would not introduce an active RNA pol II promoter into the genome are attractive for further development of safe gene therapy agents.

Genes, tat↗
PubMed2001

Replication of dengue virus type 2 in human monocyte-derived macrophages: comparisons of isolates and recombinant viruses with substitutions at amino acid 390 in the envelope glycoprotein.

The severity of dengue virus infection ranges from mild fever to dengue hemorrhagic fever and shock syndrome. The association of disease severity with virus replication in monocyte-derived macrophages (MDMs) was examined for dengue virus type 2 (DEN-2) isolates from Asia or America. Additionally, we constructed DEN-2 recombinant viruses with substitutions at residue 390 in the envelope glycoprotein (E390) because this residue is linked with the region of virus origin. Comparisons of virus yields of 3 isolates failed to show a correlation with clinical disease. However, the American strain did not replicate as well as the 2 Asian strains. For the recombinant viruses, substitution of Asn (Asian) at E390 with Asp (American) resulted in decreased ability to replicate in MDMs. These results are consistent with the proposal that the lack of association of native American DEN-2 strains with severe disease is linked to reduced ability to replicate in MDMs, and that Asp at E390 may contribute to this reduction.

Animals↗
PubMed2000

High vesicular monoamine transporter binding in asymptomatic bipolar I disorder: sex differences and cognitive correlates.

OBJECTIVE: It has been hypothesized that anomalies in monoaminergic function underlie some of the manifestations of bipolar disorder. In this study the authors examined the possibility that trait-related abnormalities in the concentration of monoaminergic synaptic terminals may be present in patients with asymptomatic bipolar disorder type I. METHOD: The concentration of a stable presynaptic marker, the vesicular monoamine transporter protein (VMAT2), was quantified with (+)[(11)C]dihydrotetrabenazine (DTBZ) and positron emission tomography. Sixteen asymptomatic patients with bipolar I disorder who had a prior history of mania with psychosis (nine men and seven women) and individually matched healthy subjects were studied. Correlational analyses were conducted to examine the relationship between regional VMAT2 binding, cognitive function, and clinical variables. RESULTS: VMAT2 binding in the thalamus and ventral brainstem of the bipolar patients was higher than that in the comparison subjects. VMAT2 concentrations in these regions correlated with performance on measures of frontal, executive function. In addition, sex differences in VMAT2 binding were detected in the thalamus of the bipolar patients; the male patients had higher binding than the women. No sex differences in binding were observed in the healthy comparison group. CONCLUSIONS: These initial results suggest that higher than normal VMAT2 expression and, by extension, concentration of monoaminergic synaptic terminals, may represent a trait-related abnormality in patients with bipolar I disorder and that male and female patients show different patterns. Also, VMAT2 concentrations may be associated with some of the cognitive deficits encountered in euthymic bipolar disorder.

Adult↗
PubMed1999

Rapid and efficient cell-to-cell transmission of human immunodeficiency virus infection from monocyte-derived macrophages to peripheral blood lymphocytes.

Macrophages are considered of central importance in cell-to-cell transmission of human immunodeficiency virus (HIV) infection in vivo. In this report, we describe a novel cell-to-cell transmission model using HIV-infected monocyte-derived macrophages (MDMs) as donor cells and peripheral blood lymphocytes (PBLs) as recipients. Virus was transmitted during a 2-h coincubation period from intracellular or tightly cell-associated viral stores in adherent infected MDMs to nonadherent CD3(+) PBLs. Transmission required cell contact, but syncytia formation was not observed. HIV cell-to-cell transmission occurred in both allogeneic and autologous systems, and replication was higher in phytohemagglutinin (PHA)-stimulated than unstimulated recipient PBLs. In contrast, transmission of infection by cell-free virus was barely detectable without PHA stimulation of recipients, suggesting the cell-cell interaction may have provided stimuli to recipient cells in the cell-to-cell system. Viral DNA levels increased 5-24 h postmixing, and this increase was inhibited by pretreatment of cells with the reverse transcription inhibitor azidothymidine, indicating de novo reverse transcription was involved. Cell-to-cell transmission was more efficient than infection with cell-free virus released from donor MDMs, or 0.1 TCID(50)/cell cell-free viral challenge. This model provides a system to further investigate the mechanisms and characteristics of HIV cell-to-cell transmission between relevant primary cells that may be analogous to this important mode of virus spread in vivo.

Cells, Cultured↗
PubMed1999

Families at the bedside: an ethnographic study of vigilance.

BACKGROUND: Vigilance, the close protective involvement of family members with hospitalized relatives, is a relatively recent phenomenon in the hospital setting. Before the 1960s, hospital visiting policies restricted the presence of family members at the bedside. Policies changed during the 1960s and 1970s when health care professionals recognized that parents' staying with their hospitalized children was beneficial for both the parents and the children. Vigilance later became a phenomenon that included family members staying with adult patients. METHODS: Two ethnographic studies were conducted to examine the meanings, patterns, and day-to-day experience of vigilance. Sixteen family members, described by the nursing staff as staying with the patient, participated in informal semistructured interviews. Participant observation was also used in data collection. RESULTS: Data analysis yielded 5 categories of meaning that describe the experience of vigilance: commitment to care, emotional upheaval, dynamic nexus, transition, and resilience. CONCLUSIONS: Managed care, shortened hospital stays, and cost containment make early involvement of the family in the patient's care imperative. An understanding of the family's needs and experiences is prerequisite to that involvement. The categories of meaning discovered in this research can help health care providers understand family members' experience of vigilance. The implications for the family physician include sensitization and awareness of family members' experiences and the developing of specific actions and interactions fostering a commitment to family-centered care that extends to the hospital setting.

Adolescent↗
PubMed1998

Secretion in Escherichia coli and phage-display of recombinant insulin-like growth factor binding protein-2.

Insulin-like growth factors (IGFs) promote cell growth and differentiation. Their actions are regulated by six different, but related, binding proteins (IGFBPs). To investigate the molecular interactions between IGFs and IGFBPs, an Escherichia coli based production method and a phage display system has been developed. The cDNA for bovine IGFBP-2 was inserted between regions coding for the pelB signal sequence and geneIII product, g3p, of bacteriophage fd in a phagemid vector to generate pGF14. The coding sequences of IGFBP-2 and g3p were separated by an amber stop codon and a flexible linker containing the cleavage recognition site for H64A subtilisin. Using this system in BL21, a non-supE strain lacking ompT, most product, approximately 4 mg 1(-1) of IGFBP-2, was obtained in the growth medium. The bacterially derived IGFBP-2 had a correct N-terminal sequence, molecular mass on SDS-PAGE and the same affinity for IGF-1 and IGF-II as IGFBP-2 from mammalian cells. In a supE strain of E. coli, IGFBP-2 was produced as an IGF-binding fusion to g3p. Procedures for display and approximately 10000 fold enrichment of IGFBP-2 bearing phage using adsorption to IGF-II coated microtitre plates were developed. Thus IGFBP-2 can be secreted in E. coli and displayed on filamentous phage. These can be selectively enriched by binding to immobilised IGF-II.

Amino Acid Sequence↗
PubMed1998

CD34+ cells and their derivatives contain mRNA for CD4 and human immunodeficiency virus (HIV) co-receptors and are susceptible to infection with M- and T-tropic HIV.

Highly purified (>98%) CD34+ cells directly after isolation (D0) or 2 weeks in culture (D14) were CD4+ and contained mRNA for the T-tropic HIV co-receptor, CXCR-4, and minor co-receptor, CCR-2B. D14 but not D0 cells were RT-PCR positive for mRNA for the major M-tropic human immunodeficiency virus (HIV) co-receptor, CCR-5, and potential co-receptor, CCR-1. D14 and D0 cells were susceptible to T- (HXB2) and M-tropic HIV (Bal), showing greater virus production with Bal than HXB2, and with higher virus production levels in D14 compared to D0 cells. Seven days post-infection of D0 cells Bal DNA was present in CD14bright and CD14- fractions, suggesting D0 infection of diverse progenitor types. HXB2 DNA was detected in CD14bright cells alone indicating D0 infection of monocyte progenitors only. It is concluded that CD34+ cells and cultured derivatives are susceptible to M- and T-tropic HIV and this correlates in part with co-receptor expression at the mRNA level.

Antigens, CD↗
PubMed1998

Vigilance as a caring expression and Leininger's theory of cultural care diversity and universality.

Vigilance, or the close, protective involvement of families caring for hospitalized relatives, was explored in this study using holistic ethnography. Leininger's theory of cultural care diversity and universality provided direction for the researcher to generate substantive data about the meanings, patterns, and day-to-day experience of vigilance. Five categories of meaning were derived from the data: commitment to care, emotional upheaval, dynamic nexus, transition, and resilience. The research findings expand understanding of vigilance as a caring expression, suggest direction for nursing practice, and contribute to Leininger's theory of cultural care diversity and universality and the development of nursing science.

Anthropology, Cultural↗
PubMed1997

The family's experience of vigilance: challenges for nursing.

The article reports a qualitative study examining vigilance, or the close, protective involvement of families who stay with their hospitalized relatives. Participants described the meanings, patterns, and day-to-day experience of vigilance through five categories of meaning: commitment to care, emotional upheaval, dynamic nexus, transition, and resilience. These categories of meaning sensitize nurses to the family's experience of vigilance and have significant implications for nursing practice.

Awareness↗
PubMed1996

Megaloblastosis.

Explore the source record for details and available documents.

Anemia, Megaloblastic↗
PubMed1996

Significance of D-dimer concentrations during and after cardiopulmonary bypass.

OBJECTIVE: To determine whether D-dimer fragments predictably increase during cardiopulmonary bypass (CPB), and if so, whether increases correlate with postoperative blood loss or predict postoperative coagulopathy. DESIGN: Prospective observational study of 65 consecutive patients undergoing first-time coronary artery bypass graft (CABG) or first-time valve replacement. SETTING: Single center University teaching hospital. PARTICIPANTS: Male and female patients between the ages of 30 and 90 years undergoing first-time CABG or valve replacement surgery using CPB. Patients were excluded from study for prolonged preoperative bleeding time, preoperative warfarin therapy, perioperative intra-aortic balloon pump support, thrombolytic therapy in the week preceding operation, reoperation, and emergency operation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Blood sampling for platelet count, prothrombin time, partial thromboplastin time, thrombin time, fibrinogen, activated coagulation time (ACT) and D-dimer concentrations was obtained at four times during each case; (1) preoperatively, after insertion of the internal jugular introducer, before insertion of pulmonary artery catheter; (2) during CPB at 28 degrees C, immediately before rewarming; (3) after heparin neutralization (20 minutes after initial protamine dose); (4) 12 to 24 hours postoperatively. Blood loss in the intensive care unit was calculated by measuring total mediastinal drainage output at 1 and 4 hours after arrival from the operating room. An initial decrease in fibrinogen was noted during bypass, but no increase in D-dimer was identified. A few patients developed a modest increase in D-dimer after heparin neutralization, but none greater than 2.0 ug/mL. Postoperatively, fibrinogen concentration increased toward baseline levels. However, this is when six patients developed significant (> 2.0 ug/mL) D-dimer formation. Results suggest appropriate physiologic response-normalization of fibrinogen with new synthesis and remodeling of clot in the operative site causing D-dimer formation. Patients with highest D-dimer levels at 12 to 24 hours postoperatively had the highest blood loss at 4 hours postoperatively, suggesting that early postoperative excess bleeding predisposed to increased clot formation and subsequent clot remodeling causing elevated D-dimer concentrations. CONCLUSIONS: D-dimer concentration is not usually elevated in patients undergoing CPB when adequately anticoagulated as monitored using the ACT. When mild elevation of D-dimer occurs, it is most often after heparin neutralization and/or in the postoperative period and is not predictive of increased postoperative blood loss. Elevations of D-dimer concentrations in the postoperative period without corresponding decreases in fibrinogen concentrations may occur and do not signify coagulopathy.

Adult↗
PubMed1996

Who cares for the mentally ill? Theory and practice hours with a 'mental illness' focus in nursing curricula in Australian universities.

Should we be concerned about the amount of undergraduate and postgraduate theory and practice hours nurses undertake caring for people with mental illness? Information on mental health curricula was sought from all university schools of nursing in Australia. There was an 84% response rate. For undergraduate courses the findings indicated great variability among schools. In one school students had 30 hours theory and no practice hours, compared with another school's 128 hours of theory and 200 practice hours. Few courses were available at the postgraduate level and the content of these courses did not appear to reflect students' previous experience in mental health/psychiatric nursing. This implies that students could graduate with limited practical experience. Without a clearly articulated career pathway, based on nationally agreed practice and educational requirements, it is difficult to see how mental health/psychiatric nurses can continue to claim they belong to a professional specialist discipline.

Australia↗
PubMed1995

Analysis of insulin-like growth factor binding proteins in the tammar wallaby, Macropus eugenii.

The insulin-like growth factors (IGFs) are important regulators of growth and development in eutherian mammals. In this study we have analyzed circulating insulin-like growth factor binding proteins (IGFBPs) by Western ligand blotting (WLB) and neutral gel filtration, and hepatic IGFBP mRNA transcripts in the wallaby, Macropus eugenii, a marsupial in which the fetus is born at an immature stage compared to eutherian mammals. Plasma from male and female adults, lactating mothers, and pouch young contains an IGF binding species consisting of a 42- to 50-kDa doublet, 30, 28, 24, and approximately 200 kDa, as shown by WLB. This pattern of IGFBPs is very similar to that observed in human and sheep. Neutral gel filtration revealed IGF binding activity of molecular size 70-160 kDa. When electrophoresed under nonreducing, denaturing conditions, the 70- to 160-kDa IGF binding activity appeared as a 42- to 50-kDa doublet, indicating the presence of a high-molecular-weight circulating IGF binding complex. These properties are again analogous to those observed for eutherian IGFBPs. Northern analysis of total wallaby liver RNA detected transcripts of 1.8 kb for IGFBP-1 and 1.6 kb for IGFBP-2, the same as those observed in the sheep and rat. Transcripts of 3.2 kb were detected for IGFBP-4, larger than the major band of 2.6 kb observed for the sheep and rat. Transcripts representing wallaby IGFBP-3 mRNA were not detected using a rat IGFBP-3 cDNA probe. Circulating IGFBPs were analyzed in plasma from wallaby mothers and their pouch young. There were no changes in circulating IGFBPs in the wallaby mothers throughout lactation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Circulating insulin-like growth factors (IGFs), IGF-binding proteins (IGFBPs) and tissue mRNA levels of IGFBP-2 and IGFBP-4 in the ovine fetus.

The IGF-binding proteins (IGFBPs) are a family of at least six structurally related proteins, which bind the IGFs and modulate their actions, including the regulation of pre- and postnatal growth. In this study we have examined the relationship between circulating and tissue mRNA levels of IGFBPs and related this to circulating IGFs in the fetal sheep over the gestational period when rapid growth and development occurs. Circulating IGFBP-2, as measured by Western ligand blot (WLB), increases between early and mid gestation, remains high, then declines throughout late gestation (P = 0.0002). Circulating IGFBP-3 increases throughout gestation, as measured by WLB or RIA (P = 0.04 and P = 0.0001 respectively), as does circulating IGFBP-4 (P = 0.004). These ontogenic changes in circulating IGFBPs-2 and -4 are paralleled by changes in liver mRNA for these proteins and, for IGFBP-2, by those in kidney IGFBP-2 mRNA also. This suggests that liver and kidney may be the primary contributors to circulating IGFBP-2 and the liver to circulating IGFBP-4, IGFBP-2 mRNA is present in the heart and lung in early gestation but barely detectable in these tissues after approximately 60 days gestation. IGFBP-4 mRNA is also present in the heart in early but not late gestation, but is abundant in the lung throughout gestation. These results demonstrate tissue specific and developmental regulation of IGFBPs-2 and -4 at the mRNA level. To assess any role the circulating IGFs may play in mediating these changes in IGFBPs, or vice versa, both plasma IGF-I and IGF-II were measured by RIA. Circulating IGF-I increases as gestation progresses (P = 0.0001), while circulating IGF-II increases between early and mid gestation, remains high (P = 0.01), then declines. Circulating IGF-I is positively correlated with fetal weight (r = 0.66, P = 0.03), circulating IGFBP-3 (r = 0.54, P = 0.01) and IGFBP-4 (r = 0.52, P = 0.01). Circulating IGF-II positively correlates with circulating IGFBP-2 (r = 0.48, P = 0.02) throughout gestation and at 1 day postnatally. These relationships are consistent with circulating IGF-I influencing IGFBPs-3 and -4, and similarly, IGF-II determining IGFBP-2, or vice versa. Alternatively, these correlations may reflect coordinate regulation of IGF and IGFBP by a common factor.

Animals↗
PubMed1994

Isolation and characterization of ovine IGFBP-4: protein purification and cDNA sequence.

Three different molecular mass forms of IGF-binding proteins (IGFBPs) were purified from ovine plasma by IGF-I affinity chromatography and reverse-phase HPLC: a 46 kDa doublet and 29 kDa and 24 kDa forms. Amino-terminal sequence analysis confirmed that these proteins were ovine (o)IGFBP-3 (46 kDa) and two molecular size variants of oIGFBP-4. oIGFBP-3 and the 29 kDa form of oIGFBP-4 were shown to be N-glycosylated. Isoelectric points were determined to be at approximately pH 6 for oIGFBP-3 and at pH 7 and pH 7.5 for the 29 and 24 kDa forms of oIGFBP-4 respectively. The two different molecular mass variants of oIGFBP-4 had similar IGF-binding properties. Compared with human IGFBP-3 and oIGFBP-3, the two variants of oIGFBP-4 exhibited lower relative binding to amino-terminally modified IGF-I analogues in a competitive IGF-binding assay. The full protein sequence of oIGFBP-4, as deduced from the cDNA sequence, showed a high degree of identity with rat (90%), human (96%) and bovine (98%) IGFBP-4. The cDNA sequence also showed homology over regions of the 3' non-coding sequence, particularly in comparison with bovine IGFBP-4 (96%). Northern analysis of mRNA for oIGFBP-4 indicated a 2.6 kb major transcript and two minor transcripts of approximately 2.1 and 1.8 kb. oIGFBP-4 mRNA transcripts were detected in adult ewe liver > kidney > lung >> heart and also in several fetal tissues, thus suggesting tissue-specific and developmental regulation. The availability of purified oIGFBP-4 and oIGFBP-3 as well as DNA probes for oIGFBP-4 will enable further study of the properties and functions of these proteins, as well as the establishment of specific assays for these IGFBPs.

Amino Acid Sequence↗