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J Maxwell

Publications and source records attributed to J Maxwell.

At least 19 recordsLinked to original sources

Basis of substrate binding by the chaperonin GroEL.

The molecular chaperonins are essential proteins involved in protein folding, complex assembly, and polypeptide translocation. While there is abundant structural information about the machinery and the mechanistic details of its action are well studied, it is yet unresolved how chaperonins recognize a large number of structurally unrelated polypeptides in their unfolded or partially folded forms. To determine the nature of chaperonin-substrate recognition, we have characterized by NMR methods the interactions of GroEL with synthetic peptides that mimic segments of unfolded proteins. In previous work, we found using transferred nuclear Overhauser effect (trNOE) analysis that two 13 amino acid peptides bound GroEL in an amphipathic alpha-helical conformation. By extending the study to a variety of peptides with differing sequence motifs, we have observed that peptides can adopt conformations other than alpha-helix when bound to GroEL. Furthermore, peptides of the same composition exhibited significantly different affinities for GroEL as manifested by the magnitude of trNOEs. Binding to GroEL correlates well with the ability of the peptide to cluster hydrophobic residues on one face of the peptide, as determined by the retention time on reversed-phase (RP) HPLC. We conclude that the molecular basis of GroEL-substrate recognition is the presentation of a hydrophobic surface by an incompletely folded polypeptide and that many backbone conformations can be accommodated.

Amino Acid Sequence↗

Search for life on Mars.

A multi-user integrated suite of instruments designed to optimize the search for evidence of life on Mars is described. The package includes: -Surface inspection and surface environment analysis to identify the potential Mars landing sites, to inspect the surface geology and mineralogy, to search for visible surficial microbial macrofossils, to study the surface radiation budget and surface oxidation processes, to search for niches for extant life. -Subsurface sample acquisition by core drilling -Analysis of surface and subsurface minerals and organics to characterize the surface mineralogy, to analyse the surface and subsurface oxidants, to analyse the mineralogy of subsurface aliquots, to analyse the organics present in the subsurface aliquots (elemental and molecular composition, isotopes, chirality). -Macroscopic and microscopic inspection of subsurface aliquots to search for life's indicators (paleontological, biological, mineralogical) and to characterize the mineralogy of the subsurface aliquots. The study is led by ESA Manned Spaceflight and Microgravity Directorate.

Europe↗

Hypnosis and cancer: an annotated bibliography 1985-1995.

The purpose of this annotated bibliography is to provide the reader with resources to explore the relationship between hypnosis and cancer. Items are included only if they contain explicit reference to this relationship and describe it in some detail. This bibliography includes 91 items published in English from 1985 to 1995, inclusive. For the reader's convenience, the annotations are organized into three categories: general discussions; case reports or case studies; and experimental and nonexperimental group designs.

Humans↗

Hypnosis for children and adolescents with cancer: an annotated bibliography, 1985-1995.

This annotated bibliography reviews the professional literature published in English, from 1985 to 1995 inclusive, on the subject of the use of hypnosis with pediatric cancer patients. Books, chapters, and journal articles are included; dissertation, theses, and unpublished material are not. This bibliography contains 37 items organized into three categories: (1) General Discussions; (2) Case Reports or Case Studies: and (3) Experimental and Nonexperimental Group Designs. The brief annotations provided are not intended to be reviews or to be evaluative, but, rather, to inform the reader about the content and focus of the publication. This is an update of a previously published annotated bibliography, also presented in this Journal, which explored the relationship between hypnosis and pediatric cancer in journal articles published from 1960 to 1985.

Adolescent↗

To treat? To befriend? To prevent? Patients' and GPs' views of the doctor's role.

OBJECTIVE: To examine and compare patients' and GPs' views of the doctor's role and patients' reasons for going to the doctor. DESIGN: A cross sectional questionnaire survey. SETTING: General practices across England. SUBJECTS: 501 patients and 68 GPs. MAIN OUTCOME MEASURES: Beliefs about the doctors' role and beliefs about patients' reasons for going to the doctor in terms of illness treatment, a psychosocial approach and preventive health care. RESULTS: A majority of both patients and GPs agreed that the doctor's role was primarily to treat illness. However, whereas patients showed greater endorsement for preventive health care and a belief that the doctor's role was to keep people healthy, GPs showed greater support for an emphasis on personal problems. In terms of patients' reasons for visiting their doctor, a majority of both patients and GPs agreed that illness prevention and illness treatment were important. However, more patients believed that patients visit the doctor for illness prevention than GPs, more of whom felt that patients seek help with their personal problems. CONCLUSION: The results indicate a mismatch between patients' and GPs' beliefs, which has implications for understanding the impact of recent changes in primary care and the effects on GPs' job satisfaction.

Adult↗

Perceptual integration of motion and form information: is the movement filter involved in form discrimination?

Seven experiments reinvestigated J. Driver and P. McLeod's (1992) report of a "visual search asymmetry reversal" in a task that required the integration of motion and form information. They found that, when the form discrimination was easy, search was more efficient for a moving rather than a stationary conjunction target; the reverse was true when form discrimination was difficult. J. Driver and P. McLeod proposed that 2 mechanisms are involved: a "stationary form system," which supports accurate form discrimination but is relatively insensitive to movement, and a "movement filter," which segregates the moving from the stationary items but is relatively insensitive to aspects of form. The present experiments failed to find the asymmetry reversal. The results agree with the (more parsimonious) proposal that the function of the movement filter is limited to separating moving from stationary items, whereas form discrimination is accomplished within a unitary form system.

Adolescent↗

Directionally selective short-term nonconjugate adaptation of vertical pursuits.

We investigated the contribution of fixation phoria and dynamic processes to short term (1 hr) nonconjugate adaptation of vertical pursuits. Unequal aftereffects were observed in vertical phoria measured during stationary gaze and during pursuits (static fixation and pursuit phorias) demonstrating direction-specific aftereffects of pursuit phoria that were not evident in measures of fixation phoria. A linear model describes the combination of fixation phoria and three dynamic direction-specific components which include a gain component that determines nonconjugate velocity, a phase component that determines the relative position of binocular pursuits, and a small position specific pursuit phoria adjustment process. Larger position-specific variations of fixation phoria appear to compensate for inappropriate or incomplete adaptive changes produced by two of the dynamic mechanisms which are not position specific.

Adaptation, Ocular↗

Spatial aspects of vertical phoria adaptation.

Vergence adaptation to vertical disparity spreads to unadapted directions of gaze. The spatial spread function for prism adaptation was estimated from aftereffects of a vertical disparity presented at a single position. Constraints limiting the spatial spread of adaptation were investigated with two stimuli of opposite disparity (hyper and hypo), presented at two different eye positions with a separation that varied from 6 to 18 deg in either the horizontal or vertical meridian. On average, phoria adaptation to the single point paradigm spread uniformly across the entire 18 deg test field. A resolution limit for adaptation to the two point paradigm was demonstrated by a reduction of phoria aftereffects with decreasing target separation (crowding). Vertical phoria aftereffects were reduced more by horizontal than by vertical crowding. A disparity gradient limit was demonstrated for a fixed target separation by a reduction of gain (phoria change/stimulus disparity) with increasing stimulus disparity.

Adaptation, Ocular↗

Healing images.

Explore the source record for details and available documents.

Adaptation, Psychological↗

Robust and inexpensive equipment design for polymerase chain reaction detection of sequence mutations. Cystic fibrosis in a mother and 2 children analysed.

Every polymerase chain reaction (PCR) requires use of a temperature cycler for about 3 hours. Since there are many diagnostic tests using this technology, it is important that robust but inexpensive machinery is available. Such a stand-alone machine has been designed and used to analyse an interesting family in which a mother and her 2 children were diagnosed as having cystic fibrosis.

Adult↗

HIV-1 associated cognitive/motor complex in an injecting drug user.

The clinical and social consequences of AIDS dementia complex/HIV-1 associated cognitive/motor complex (ADC/HACC) in drug users have not been well documented. The value of prospective serial neuropsychological, neuroradiological and neurophysiological measurements to assist diagnosis of ADC/HACC in patients with premorbid personality disorder and intercurrent drug use is demonstrated. The psychosocial problems resulting from ADC/HACC with respect to community care and the location of hospitalization is considered. The relevance of the 1984 Mental Health Act (Scotland) with regard to drug users with ADC/HACC is discussed.

AIDS Dementia Complex↗

Survival of feline mycoplasmas in urine.

The effects of length of incubation and urine osmolality on the survival of feline mycoplasmas and ureaplasmas and representative gram-positive and gram-negative bacteria in synthetic urine which approximated the osmolality of normal cat urine were investigated. Both Escherichia coli and Staphylococcus aureus withstood the effects of increasing osmotic pressure. In the most concentrated urine, significant decreases (P less than 0.001) in CFU were observed for E. coli at exposure times of 30 min and longer. S. aureus was not affected by longer exposure or increased osmotic strength. Both Mycoplasma felis and Mycoplasma gateae were affected adversely by longer exposure times and high osmotic strength (P less than 0.001). A Ureaplasma sp. was not adversely affected except at very high (greater than or equal to 2,980 mosM) osmotic strengths or after prolonged incubation (120 min) at relatively high (1,976 mosM) osmotic strengths (P less than 0.001). The failure of both M. felis and M. gateae to survive under osmotic conditions present in normal feline urine suggests that it is unlikely that these mycoplasmas are involved in urinary disorders in cats.

Animals↗