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Biomedical subjects

J Morris

Publications and source records attributed to J Morris.

At least 145 records · Page 8Linked to original sources
PubMed1999

Efficient transduction by an amphotropic retrovirus vector is dependent on high-level expression of the cell surface virus receptor.

Transduction by murine leukemia virus-based retrovirus vectors is limited in certain cell types, particularly in nondividing cells. But transduction can be inefficient even in cells that divide rapidly. For example, exposure of 208F rat embryo fibroblasts to an excess of an amphotropic retrovirus vector encoding alkaline phosphatase results in a transduction efficiency of only about 10%, even though these cells divide rapidly. Here we show that transduction of 208F cells is limited by cell surface retrovirus receptor levels; overexpression of the amphotropic retrovirus receptor Pit2 markedly improved the transduction efficiency to 50%. To characterize receptor levels and binding affinity, we synthesized a fusion protein that joins the amino terminus of the amphotropic envelope protein to the Fc region of a human immunoglobulin G1 molecule for use in binding assays. In comparison to the parental cell line, the modified cell line showed an order of magnitude increase in binding sites of from 18,000 to 150,000 per cell. Thus, efficient transduction by an amphotropic retrovirus vector requires high-level expression of the retrovirus receptor Pit2. These results provide the rationale for further examination of the role of receptor levels in inefficient transduction, especially with regard to target cells for gene therapy, where a high transduction rate is often crucial.

Animals↗
PubMed1999

Biophysical characterization and modeling of lung surfactant components.

The present study characterizes the dynamic interfacial properties of calf lung surfactant (CLS) and samples reconstituted in a stepwise fashion from phospholipid (PL), hydrophobic apoprotein (HA), surfactant apoprotein A (SP-A), and neutral lipid fractions. Dipalmitoylphosphatidylcholine (DPPC), the major PL component of surfactant, was examined for comparison. Surface tension was measured over a range of oscillation frequencies (1-100 cycles/min) and bulk phase concentrations (0.01-1 mg/ml) by using a pulsating bubble surfactometer. Distinct differences in behavior were seen between samples. These differences were interpreted by using a previously validated model of surfactant adsorption kinetics that describes function in terms of 1) adsorption rate coefficient (k1), 2) desorption rate coefficient (k2), 3) minimum equilibrium surface tension (gamma*), 4) minimum surface tension at film collapse (gammamin), and 5) change in surface tension with interfacial area for gamma < gamma* (m2). Results show that DPPC and PL have k1 and k2 values several orders of magnitude lower than CLS. PL had a gammamin of 19-20 dyn/cm, significantly greater than CLS (nearly zero). Addition of the HA to PL restored dynamic interfacial behavior to nearly that of CLS. However, m2 remained at a reduced level. Addition of the SP-A to PL + HA restored m2 to a level similar to that of CLS. No further improvement in function occurred with the addition of the neutral lipid. These results support prior studies that show addition of HA to the PL markedly increases adsorption and film stability. However, SP-A is required to completely normalize dynamic behavior.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1999

Durability of the effects of cognitive-behavioural therapy in the treatment of chronic schizophrenia: 12-month follow-up.

BACKGROUND: Persistent drug-resistant psychotic symptoms are a pervasive problem in the treatment of schizophrenia. AIMS: To evaluate the durability of the treatment effects of cognitive-behavioural therapy for chronic schizophrenia one year after treatment termination. METHOD: A comparison of clinical outcomes was made at one-year follow-up from a randomised trial of cognitive-behavioural therapy, supportive counselling and routine care alone in the treatment of chronic schizophrenia. RESULTS: Seventy out of the 72 patients (97%) who completed treatment were assessed at follow-up. There were significant differences between the three groups when positive and negative symptoms were analysed by means of ANCOVAs. Between-group comparisons indicated significant differences between cognitive-behavioural therapy and routine care at follow-up for positive symptoms. There was a trend towards significance for both cognitive-behavioural therapy and supportive counselling to be superior to routine care alone on negative symptoms. CONCLUSIONS: At 12-month follow-up the significant advantage of cognitive-behavioural therapy compared to routine care alone remained.

Adolescent↗
PubMed1999

Sweet's syndrome as an initial manifestation of pediatric human immunodeficiency virus infection.

We report a 3-month-old infant in whom Sweet's syndrome was a presenting manifestation of pediatric human immunodeficiency virus infection. Although rare in children, Sweet's syndrome may be associated with certain infections and malignancies. The diagnosis of Sweet's syndrome in a child should always prompt a thorough evaluation to assess for an associated systemic disease.

HIV Infections↗
PubMed1999

Elucidating the pathophysiology of syringomyelia.

OBJECT: Syringomyelia causes progressive myelopathy. Most patients with syringomyelia have a Chiari I malformation of the cerebellar tonsils. Determination of the pathophysiological mechanisms underlying the progression of syringomyelia associated with the Chiari I malformation should improve strategies to halt progression of myelopathy. METHODS: The authors prospectively studied 20 adult patients with both Chiari I malformation and symptomatic syringomyelia. Testing before surgery included the following: clinical examination; evaluation of anatomy by using T1-weighted magnetic resonance (MR) imaging; evaluation of the syrinx and cerebrospinal fluid (CSF) velocity and flow by using phase-contrast cine MR imaging; and evaluation of lumbar and cervical subarachnoid pressure at rest, during the Valsalva maneuver, during jugular compression, and following removal of CSF (CSF compliance measurement). During surgery, cardiac-gated ultrasonography and pressure measurements were obtained from the intracranial, cervical subarachnoid, and lumbar intrathecal spaces and syrinx. Six months after surgery, clinical examinations, MR imaging studies, and CSF pressure recordings were repeated. Clinical examinations and MR imaging studies were repeated annually. For comparison, 18 healthy volunteers underwent T1-weighted MR imaging, cine MR imaging, and cervical and lumbar subarachnoid pressure testing. Compared with healthy volunteers, before surgery, the patients had decreased anteroposterior diameters of the ventral and dorsal CSF spaces at the foramen magnum. In patients, CSF velocity at the foramen magnum was increased, but CSF flow was reduced. Transmission of intracranial pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was partially obstructed. Spinal CSF compliance was reduced, whereas cervical subarachnoid pressure and pulse pressure were increased. Syrinx fluid flowed inferiorly during systole and superiorly during diastole on cine MR imaging. At surgery, the cerebellar tonsils abruptly descended during systole and ascended during diastole, and the upper pole of the syrinx contracted in a manner synchronous with tonsillar descent and with the peak systolic cervical subarachnoid pressure wave. Following surgery, the diameter of the CSF passages at the foramen magnum increased compared with preoperative values, and the maximum flow rate of CSF across the foramen magnum during systole increased. Transmission of pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was normal and cervical subarachnoid mean pressure and pulse pressure decreased to normal. The maximum syrinx diameter decreased on MR imaging in all patients. Cine MR imaging documented reduced velocity and flow of the syrinx fluid. Clinical symptoms and signs improved or remained stable in all patients, and the tonsils resumed a normal shape. CONCLUSIONS: The progression of syringomyelia associated with Chiari I malformation is produced by the action of the cerebellar tonsils, which partially occlude the subarachnoid space at the foramen magnum and act as a piston on the partially enclosed spinal subarachnoid space. This creates enlarged cervical subarachnoid pressure waves that compress the spinal cord from without, not from within, and propagate syrinx fluid caudally with each heartbeat, which leads to syrinx progression. The disappearance of the abnormal shape and position of the tonsils after simple decompressive extraarachnoidal surgery suggests that the Chiari I malformation of the cerebellar tonsils is acquired, not congenital. Surgery limited to suboccipital craniectomy, C-I laminectomy, and duraplasty eliminates this mechanism and eliminates syringomyelia and its progression without the risk of more invasive procedures.

Adolescent↗
PubMed1999

More on the relation between division and multiplication in simple arithmetic: evidence for mediation of division solutions via multiplication.

Adults (N = 32) solved simple multiplication (e.g., 8 x 7) and corresponding division problems (e.g., 56/8). Self-reports of solution processes were given by half of the participants. Latency patterns and error rates were closely related across operations and were similar in self-report and no-report conditions. Solution of division problems, however, facilitated solution of multiplication problems more than the reverse. On large division problems, participants reported that they "recast" problems as multiplication (e.g., 56/8 as 8 x = 56). These results support the hypothesis that multiplication and division are stored in separate mental representations but that solution of difficult division problems sometimes involves access to multiplication.

Adult↗
PubMed1999

People who make a difference. Interview by Wendy L. Bonifazi.

In last year's 20th anniversary issue, Contemporary started an annual tradition of honoring people whose innovative business practices, research, advocacy, and other efforts have shaped long term care. This year's four honorees have created groundbreaking tools for care, campaigned to promote the healthy growth of a fledgling form of care, and championed a vision for improving quality of life for residents.

Aged↗
PubMed1998

Randomised controlled trial of effects of early discharge after surgery for breast cancer.

OBJECTIVE: To determine the effect of early discharge from hospital after surgery for breast cancer on physical and psychological illness. DESIGN: Randomised controlled trial comparing discharge two days after surgery (before removal of drain) with standard management (discharge after removal of drain). SETTING: Regional breast unit. SUBJECTS: 100 women with early breast cancer undergoing mastectomy and axillary node clearance (20) or breast conservation surgery (80). MAIN OUTCOME MEASURES: Physical illness (infection, seroma formation, shoulder movement) and psychological illness (checklist of concerns, Rotterdam symptom questionnaire, hospital anxiety and depression scale) preoperatively and at one month and three months postoperatively. RESULTS: Women discharged early had greater shoulder movement (odds ratio 0.28 (95% confidence interval 0.08 to 0.95); P = 0.042) and less wound pain (odds ratio 0.28 (0.10 to 0.79); P = 0.016) three months after surgery compared with women given standard management. One month after surgery scores were significantly lower on the Rotterdam symptom questionnaire in patients who were discharged early (ratio of geometric mean scores 0.73 (0.55 to 0.98) P = 0.035), but rates of psychological illness generally did not differ between groups. CONCLUSIONS: Increased rates of physical or psychological illness did not result from early discharge after surgery for breast cancer. This policy can be recommended for patients with support at home.

Adult↗
PubMed1998

Pyrimidine thioethers: a novel class of HIV-1 reverse transcriptase inhibitors with activity against BHAP-resistant HIV.

A series of pyrimidine thioethers was synthesized and evaluated for inhibitory properties against wild-type HIV-1 reverse transcriptase (RT) and an RT carrying the resistance-conferring mutation P236L. Modifications of both the pyrimidine and the functionality attached through the thioether yielded several analogues, which demonstrated activity against both enzyme types, with IC50 values as low as 190 nM against wild-type and 66 nM against P236L RT. Evaluation of a select number of pyrimidine thioethers in cell culture showed that these compounds have excellent activity against HIV-1IIIB-WT and retain good activity against a laboratory-derived HIV-1MF delavirdine-resistant variant.

Amino Acid Substitution↗
PubMed1998

Improved gene transfer into baboon marrow repopulating cells using recombinant human fibronectin fragment CH-296 in combination with interleukin-6, stem cell factor, FLT-3 ligand, and megakaryocyte growth and development factor.

We have used a competitive repopulation assay in baboons to develop improved methods for hematopoietic stem cell transduction and have previously shown increased gene transfer into baboon marrow repopulating cells using a gibbon ape leukemia virus (GALV)-pseudotype retroviral vector (Kiem et al, Blood 90:4638, 1997). In this study using GALV-pseudotype vectors, we examined additional variables that have been reported to increase gene transfer into hematopoietic progenitor cells in culture for their ability to increase gene transfer into baboon hematopoietic repopulating cells. Baboon marrow was harvested after in vivo administration (priming) of stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF). CD34-enriched marrow cells were divided into two equal fractions to directly compare transduction efficiencies under different gene transfer conditions. Transduction by either incubation with retroviral vectors on CH-296-coated flasks or by cocultivation on vector-producing cells was studied in five animals; in one animal, transduction on CH-296 was compared with transduction on bovine serum albumin (BSA)-coated flasks. The highest level of gene transfer was obtained after 24 hours of prestimulation followed by 48 hours of incubation on CH-296 in vector-containing medium in the presence of multiple hematopoietic growth factors (interleukin-6, stem cell factor, FLT-3 ligand, and megakaryocyte growth and development factor). Using these conditions, up to 20% of peripheral blood and marrow cells contained vector sequences for more than 20 weeks, as determined by both polymerase chain reaction and Southern blot analysis. Gene transfer rates were higher for cells transduced on CH-296 as compared with BSA or cocultivation. In one animal, we have used a vector expressing a cell surface protein (human placental alkaline phosphatase) and have detected 10% and 5% of peripheral blood cells expressing the transduced gene 2 and 4 weeks after transplantation as measured by flow cytometry. In conclusion, the conditions described here have resulted in gene transfer rates that will allow detection of transduced cells by flow cytometry to facilitate the evaluation of gene expression. The levels of gene transfer obtained with these conditions suggest the potential for therapeutic efficacy in diseases affecting the hematopoietic system.

Animals↗
PubMed1998

Randomised controlled trial of intensive cognitive behaviour therapy for patients with chronic schizophrenia.

OBJECTIVES: To investigate whether intensive cognitive behaviour therapy results in significant improvement in positive psychotic symptoms in patients with chronic schizophrenia. DESIGN: Patients with chronic schizophrenia were randomly allocated, stratified according to severity of symptoms and sex, to intensive cognitive behaviour therapy and routine care, supportive counselling and routine care, and routine care alone. SETTING: Adjunct treatments were carried out in outpatient clinics or in the patient's home. SUBJECTS: 87 patients with persistent positive symptoms who complied with medication; 72 completed treatment. OUTCOME MEASURES: Assessments of positive psychotic symptoms before treatment and 3 months after treatment. Number of patients who showed a 50% or more improvement in symptoms. Exacerbation of symptoms and rates of readmission to hospital. RESULTS: Significant improvements were found in the severity (F=5.42, df =2,86; P=0.006) and number (F=4.99, df=2,86; P=0.009) of positive symptoms in those treated with cognitive behaviour therapy. The supportive counselling group showed a non-significant improvement. Significantly more patients treated with cognitive behaviour therapy showed an improvement of 50% or more in their symptoms (chi2=5.18, df=1; P=0.02). Logistic regression indicated that receipt of cognitive behaviour therapy results in almost eight times greater odds (odds ratio 7.88) of showing this improvement. The group receiving routine care alone also experienced more exacerbations and days spent in hospital. CONCLUSIONS: Cognitive behaviour therapy is a potentially useful adjunct treatment in the management of patients with chronic schizophrenia.

Adult↗
PubMed1998

A calcium-dependent tyrosine kinase splice variant in human monocytes. Activation by a two-stage process involving adherence and a subsequent intracellular signal.

Freshly isolated human monocytes do not express p125(FAK) but upon adherence to substrata activate the highly related calcium-dependent tyrosine kinase (CADTK), also known as Pyk2, CAKbeta, RAFTK, and FAK2. The monocyte CADTK was 5 kDa smaller than protein from epithelial cells; isolation and sequencing of the monocyte CADTK cDNA revealed a predicted 42-amino acid deletion between the two proline-rich domains of the enzyme. The nucleic acid sequence suggests that the deletion is caused by alternative RNA splicing. This species was also found in T and B lymphocytes and appears to be the predominant form of cytoskeletal associated tyrosine kinase in non-neoplastic, circulating, hematopoietic cells. CADTK was not activated when monocytes maintained in suspension were treated with agents that produce an intracellular calcium (thapsigargin) or protein kinase C (phorbol 12-myristate 13-acetate) signal including a chemokine, RANTES, that binds to the HIV co-receptor, CCK5. In contrast, monocyte adherence to tissue culture plastic-stimulated CADTK tyrosine phosphorylation, a process that was enhanced by thapsigargin, phorbol 12-myristate 13-acetate, and RANTES but that was completely blocked by preincubation with cytochalasin D. When compared with plastic, adherence to fibronectin- or collagen-coated surfaces produced only minimal CADTK activation but permitted significant stimulation by added thapsigargin. These data suggest that in a cell type that lacks p125(FAK), CADTK plays an early role in post-adherence signaling. Its activation involves two stages, cytoskeletal engagement, which is permissive, and co-stimulatory signals (calcium or protein kinase C) generated by extensive cell surface engagement, agonists, or inflammatory chemokines.

Alternative Splicing↗
PubMed1998

Association of malaria parasite population structure, HLA, and immunological antagonism.

Host-parasite coevolution has been likened to a molecular arms race, with particular parasite genes evolving to evade specific host defenses. Study of the variants of an antigenic epitope of Plasmodium falciparum that induces a cytotoxic T cell response supports this view. In African children with malaria, the variants present are influenced by the presence of a human leukocyte antigen (HLA) type that restricts the immune response to this epitope. The distribution of parasite variants may be further influenced by the ability of cohabiting parasite strains to facilitate each other's survival by down-regulating cellular immune responses, using altered peptide ligand antagonism.

Alleles↗