Probing minimal independent folding units in dihydrofolate reductase by molecular dissection.

Molecular dissection was employed to identify minimal independent folding units in dihydrofolate reductase (DHFR) from Escherichia coli. Eight overlapping fragments of DHFR, spanning the entire sequence and ranging in size from 36 to 123 amino acids, were constructed by chemical cleavage. These fragments were designed to examine the effect of tethering multiple elements of secondary structure on folding and to test if the secondary structural domains represent autonomous folding units.

CD4: a co-receptor in the immune response and HIV infection.

CD4 is a transmembrane glycoprotein of the immunoglobulin superfamily, expressed on developing thymocytes, major histocompatibility class II (class II MHC) restricted mature T lymphocytes and, in humans, on cells of the macrophage/monocyte lineage. On lymphoid cells, CD4 plays a critical role during thymocyte ontogeny and in the function of mature T cells. CD4 binds to non-polymorphic regions of class II MHC acting as a co-receptor for the T-cell antigen receptor (TCR).

Rough-and-tumble play behavior in Fischer-344 and buffalo rats: effects of social isolation.

Play behavior was assessed in two inbred strains of rats. Rats of the Fischer-344 strain (F344) were found to be less playful than Buffalo rats after social isolation, as evident from fewer pins and fewer playful attacks to the nape. When tested in same-strain pairings, overall defense of the nape did not differ between strains, although there were strain differences in the specific pattern of defense.

Effects of induced mood states on objective and projective dependency scores.

In two experiments involving a total of 144 participants (72 women and 72 men), we examined the effects of induced mood states on college students' scores on widely used objective and projective measures of dependency. In both experiments, induced mood states significantly influenced participants' scores on the projective dependency test but did not affect their scores on the objective dependency test. Findings are discussed in the context of previous studies comparing objective and projective dependency measures and with respect to theoretical frameworks that distinguish implicit from self-attributed dependency needs.

Hypnotic amnesia and the paradox of intentional forgetting.

Hypnotic amnesia is often interpreted as a deliberate effort to avoid thinking of ideas or thoughts targeted for amnesia. However, as D.M.

Relationships of objective and projective dependency scores to sex role orientation in college student participants.

Research on the dependency-sex role orientation relationship indicates that when objective dependency measures are used, participants show positive correlations between dependency and femininity scores, and negative correlations between dependency and masculinity scores. In this study, a mixed-sex sample of 87 undergraduates (47 women and 40 men) completed widely used objective and projective measures of dependency, and a self-report measure of sex role orientation. Consistent with previous studies in this area, high objective dependency scores were associated with high femininity scores and low masculinity scores in participants of both sexes.

Differential relationships of objective and projective dependency scores to self-reports of interpersonal life events in college student subjects.

Eighty-three undergraduate subjects (58 women and 25 men) participated in a prospective study in which they (a) completed widely used objective and projective measures of dependency, and then (b) provided monthly reports of the frequency and impact of various types of life events during a 1-semester (3-month) period. As expected, subjects' projective dependency scores predicted their frequency estimates and impact ratings of interpersonal life events but were unrelated to frequency estimates and impact ratings of other types of life events (e.g.

Does counterpain imagery mediate hypnotic analgesia?

Sixty-six high hypnotizable individuals received a baseline exposure to pain and 2 counterbalanced hypnotic analgesia conditions. Standard analgesia invoked counterpain imagery, whereas imageless analgesia proscribed imagery. The mean level of pain reduction in these 2 conditions was virtually identical and significantly less than the pain rated in the baseline condition.

Cytoplasmic factors that affect the intensity and stability of bioluminescence from firefly luciferase in living mammalian cells.

In order to improve calibration of firefly luciferase signals obtained by injecting the enzyme into single, isolated heart and liver cells we have investigated why the luminescence from cells is greatly depressed compared with in vitro (in mammalian ionic milieu) and why the decay of the intracellular signal is remarkably slow. We have shown that inorganic pyrophosphatase greatly depresses the signal in vitro and that micromolar concentrations of inorganic pyrophosphate, comparable with that in cytoplasm, reverse this inhibition and stabilize the signal, eliminating its decay. Higher concentrations of pyrophosphate depress the signal by inhibiting ATP-binding to luciferase.

Continuous measurements of cytoplasmic ATP in single cardiomyocytes during simulation of the "oxygen paradox".

Objective: It is now possible to monitor cytoplasmic ATP in single cardiomyocytes and it has recently been shown that cardiomyocytes exposed for several minutes to metabolic inhibitors undergo an abrupt rigor mediated shortening which coincides with a sudden fall in cytoplasmic ATP, from approximately 150 mumol.litre-1 to a few micromolar or less. The objective of this work was to monitor cytoplasmic ATP during simulated reoxygenation of a poisoned cardiomyocyte.

Hypnotic analgesia: dissociated experience or dissociated control?

High-hypnotizable subjects (n = 18) were superior to low-hypnotizable subjects (n = 18) in the extent of pain reduction produced by hypnotic analgesia and by a stress-inoculation procedure. However, stress inoculation but not hypnotic analgesia impaired performance on a cognitively demanding task that competed with pain reduction for cognitive resources. This outcome implies that hypnotic analgesia occurs with little or no cognitive effort to reduce pain and challenges the social psychological model of hypnosis.

The Waterloo-Stanford Group C (WSGC) scale of hypnotic susceptibility: normative and comparative data.

The Waterloo-Stanford Group C (WSGC) hypnotic susceptibility scale was developed as a substitute for the individually administered Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C). A first investigation with WSGC reports normative data on 259 subjects, and the results indicate that it is comparable in most important respects to the norms of SHSS:C. A second investigation directly compared WSGC and SHSS:C in a counterbalanced design on 65 subjects, and the two scales correlated .

Imagination and dissociation in hypnotic responding.

A neodissociative model of mind is better equipped than a social-psychological model to deal with the complexities of hypnosis, and of human behavior generally. It recognizes, as Coe's (1992) model does not, that behavior can be more automatically activated than strategically enacted. In particular, Coe's emphasis on human behavior as purposeful and goal directed does not distinguish between goal-directed behavior that serves a purpose, and goal-directed behavior that is performed on purpose.

Bioluminescent measurement in single cardiomyocytes of sudden cytosolic ATP depletion coincident with rigor.

The sequence of events that leads to irreversible injury of the ischaemic myocardium is poorly understood but it is axiomatic that lack of oxygen will impair regeneration of ATP. In the globally-ischaemic heart a contracture develops which is independent of raised cytoplasmic free Ca2+ and which has been attributed to activation of actomyosin by nucleotide-free actomyosin cross-bridges ('rigor complexes') which form at low ATP concentrations. Single, metabolically-poisoned or anoxic cardiomyocytes show comparable behaviour, shortening before a significant rise in cytoplasmic free Ca2+ occurs.

Incidence of Hyperpronation in the ACL Injured Knee: A Clinical Perspective.

Assessing abnormal biomechanics when treating various lower extremity pathologies provides the athlete with comprehensive management and promotes injury prevention. However, there have been few previous investigations of abnormal biomechanical forces on ligamentous pathologies of the knee. During this clinical study we investigated the incidence of hyperpronation in subjects who have had an anterior cruciate ligament (ACL) injury.

Optimization of surface micromorphology for enhanced osteoblast responses in vitro.

In vitro cellular responses of osteoblast-like cells were studied on titanium surfaces with different surface morphologies. Surface profilometry was used to determine whether rough or smooth surfaces with regular or irregular morphologies can be produced by conventional fabrication techniques. Significantly higher levels of cellular attachment were found using rough, sandblasted surfaces with irregular morphologies.

Migrating a clinical laboratory information system between technologies.

The technical revolution that has strongly driven events in the clinical laboratory for the last thirty years is now threatening to make obsolete what has become the central pillar of operation in many laboratories, the minicomputer-based laboratory information system. Some of its functions could easily be absorbed by the personal computers which are proliferating in the laboratory, but any single step leap between systems risks replacing order with chaos. Appropriate use of networking tools, together with essential software development, can provide a systematic migrational path for both the administrative and technical computer support from one environment to another without the trauma of a massive replacement step.

Dissociation in hypnosis and multiple personality disorder.

The first part of this paper examines the concept of dissociation in the context of hypnosis. In particular, the neodissociative and social psychological models of hypnosis are compared. It is argued that the social psychological model, in describing hypnotic enactments as purposeful, does not adequately distinguish between behavior that is enacted "on purpose" and behavior that serves or achieves a purpose.

Selective hypnotic amnesia: is it a successful attempt to forget or an unsuccessful attempt to remember?

Subjects in 2 experiments (ns = 72 and 50) learned a 16-item, 4-category word list and were then administered hypnotic suggestions to be amnesic for all the words in 1 of the categories. Even when selective amnesia was completely successful, subjects in both experiments revealed a high level of recall for words not targeted for amnesia; moreover, these words were recalled in a highly organized, category-by-category fashion. Evidently, attention to relevant retrieval (i.

Diagnosis of cutaneous cytomegalovirus infection: a review and report of a case.

Cytomegalovirus infections are a major source of morbidity and mortality in immunocompromised patients. We report a case of cutaneous cytomegalovirus in a patient with the acquired immunodeficiency syndrome, in which routine light microscopy was suggestive but not diagnostic of cytomegalovirus. Immunohistochemical studies of the specimen for cytomegalovirus antigens revealed numerous intracytoplasmic and intranuclear viral inclusions.