1,25-dihydroxyvitamin D3 regulates pp60c-src activity and expression of a pp60c-src activating phosphatase

The nonreceptor tyrosine kinase, c-src, and the steroid hormone,1,25-dihydroxyvitamin D3(1,25(OH)2D3), are essential to development of the osteoclast phenotype. On the other hand, functional relationships between the activities of c-src and 1,25(OH)2D3 are as yet unknown. To determine if 1,25(OH)2D3 modulates c-src in osteoclastogenesis, we tested the steroid's effect on avian marrow-derived osteoclast precursors. We find c-src mRNA and immunoprecipitable c-src protein (pp60c-src) unaltered by 72 h exposure of these cells to 1,25(OH)2D3 (10(-11) to 10(-9) M). Despite no quantitative change in pp60c-src, in vitro kinase assay of the immune complex reveals 1,25(OH)2D3 dose-dependently accelerates the catalytic activity of pp60c-src, enhancing its autophosphorylation and phosphorylation of exogenous substrate. This observation represents the first documentation, in nontransformed cells, of humoral induction of pp60c-src kinase. Consistent with the fact pp60c-src is activated by dephosphorylation of tyrosine 527 (Y527), the phosphotyrosine content of the pp60c-src immunoprecipitate, measured by immunoblot, is decreased by 1,25(OH)2D3. Alternatively, mRNA and protein levels of c-src kinase (CSK), which inactivates pp60c-src by phosphorylating Y527, are not altered by the steroid. In contrast, 1,25(OH)2D3 enhances mRNA and especially protein levels of avian protein tyrosine phosphatase lambda (PTP lambda), an enzyme specifically activating pp60c-src by dephosphorylating Y527 [Fang et al. (1994): J Biol Chem 269:20194-20200]. Thus, treatment of avian osteoclast precursors with 1,25(OH)2D3 accelerates the catalytic activity of pp60c-src independent of protein expression. Activation of the kinase may occur via the Y527 dephosphorylating enzyme PTP, expression of which, we show for the first time, is regulated.

Quaternion contact ribbons: a new tool for visualizing intra- and intermolecular interactions in proteins

Protein side chain interactions between residues separated by at least one loop or turn or break in the amino acid sequence are called 'nonlocal contacts' in this manuscript, and contiguous sets of such interactions located between segments of secondary structure are called 'contact zones.' A new interactive program, the quaternion contact ribbon tool, has been developed to help protein chemists identify, straighten if twisted, and display contact zones between two neighboring segments of helix.

Grip force scaling after hemispatial neglect

Spatial neglect has been explained as an impairment in the representation of extrapersonal space. One account suggests that representations of extrapersonal space are spatially compressed following neglect. In support of this view it has been demonstrated that neglect patients systematically underestimate the size of stimuli presented in their left hemifield. In the current study we investigated this phenomena by obtaining an indirect measure of perceived object size - the scaling of grip force during prehension. We demonstrate for the first time that neglect patients show increased levels of grip force for objects presented in their left hemifield. This finding is discussed with reference to a proposed distinction between visual processing used for object recognition, and visual processing used to guide action.

Analgesic effect of intra-articular bupivacaine or diamorphine after arthroscopic surgery of the knee joint in day-case patients

A prospective, randomized, double-blind, controlled study was conducted to assess the efficacy of intra-articular bupivacaine and diamorphine. Ninety-six day-case patients were allocated randomly to receive intra-articular injections of either 20 mL 0.9% saline (control, n = 35), 20 mL 0.5% plain bupivacaine (n = 31), or 20 mL 0.9% saline with 5 mg diamorphine (n = 30) prior to tourniquet release. Visual analogue scales (VAS) were completed at 1 h, 3 h (discharge) and 24 h, and supplementary analgesia noted. Intra-articular analgesics conferred a noticeable improvement in patient comfort. First, the quantity of supplementary analgesia required prior to discharge was significantly reduced (P = 0.016); second, patients reported a less disturbed night's sleep (P = 0.034).

Orally active trifluoromethyl ketone inhibitors of human leukocyte elastase

This paper describes the development a series of peptidyl trifluoromethyl ketone inhibitors of human leukocyte elastase which are found to have excellent pharmacological profiles. Methods have been developed that allow for the synthesis of these inhibitors in stereochemically pure form. Two of these compounds, 1k and 1l, have high levels of oral bioavailability in several species. Compound 1l has entered development as ZD8321 and is presently undergoing clinical evaluation. These compounds demonstrate that peptidyl trifluoromethyl ketone inhibitors can achieve high levels of oral activity and bioavailability, and therefore they may prove useful as therapeutic agents in the treatment of diseases in which elastase is implicated.

Humerus shaft fractures in young children: accident or abuse?

We performed a retrospective review of 34 humerus shaft fractures (HSFs) in children younger than 3 years to determine the frequency of child abuse in young children with this injury. Data were obtained from hospital records (including previous and subsequent emergency, clinic, and inpatient notes), radiographs, and county childprotective services. Cases were reviewed independently by four physicians and were classified as probable abuse, probable not abuse, and indeterminate. Only 18% were classified as probable abuse. The history and findings other than the fracture itself were critical in establishing cause. Neither age nor fracture pattern is pathognomonic of abuse, but suspicion should remain high. A detailed history, complete physical examination, and appropriate radiographic investigation are required in every case either to make the diagnosis of abuse or to avoid the trauma of a false accusation.

Patients' perceptions of changes in their blood pressure

OBJECTIVES

(1) To investigate patients' experience of changes in their blood pressure (BP) in an every day setting and the accuracy of patients' predictions; and (2) to examine what influences patients' belief that they can tell when their BP is up.

SUBJECTS

A total of 102 hypertensive patients were recruited sequentially as they presented for routine BP checks. The setting was an inner city general practice.

DESIGN

Patients attended for BP checks on a weekly basis. Before each check they were asked whether they thought their BP was higher, lower or the same as usual. Subjects were classified as predictors if they thought they could tell when their BP was up. On completing their series of BP checks each subject completed symptom and Hospital Anxiety and Depression questionnaires.

MAIN OUTCOME MEASURES

Accuracy of BP predictions, BP levels and variability, number of symptoms reported and anxiety level.

RESULTS

One hundred and two hypertensive patients entered the study of whom 51 patients were predictors. The majority (86%) of predictors could not accurately predict their BP. There were no significant differences in either BP or variability between predictors and non-predictors. Predictors were significantly more anxious and reported more symptoms than non-predictors.

CONCLUSIONS

For the majority of predictors there is no significant relationship between predictions of BP and clinical measurements. Predictor status is associated with the reporting of more symptoms and higher levels of anxiety. Doctors should counsel patients against using subjective BP assessments to guide their use of antihypertensive medication.

Opportunities for optimizing resource utilization in ambulatory academic practices

Growing emphasis on ambulatory service delivery in academic medical centers has heightened interest in improving operational efficiencies, while providing an optimal educational experience for medical students and residents. One significant challenge in the academic environment is maximizing resource utilization (both physical plant and personnel), through scheduling and operational effectiveness. This article examines how academic ambulatory practices can apply operational and scheduling process redesign methodologies to improve throughput and productivity, while enhancing the educational experience for students/residents.

Inhibition of feline immunodeficiency virus infection by CD9 antibody operates after virus entry and is independent of virus tropism

A monoclonal antibody which blocks infection with feline immunodeficiency virus (FIV) was found previously to react with the cell surface molecule CD9, implicating CD9 in the process of virus entry. We report here that inhibition by anti-CD9 antibody does not operate at the level of virus entry but at a subsequent stage in the virus life-cycle. Moreover, inhibition of infection is independent of the passage history of the virus or the virus subtype. Inhibition of FIV infection by anti-CD9 antibody does not operate in 3201 cells, which do not express this surface antigen. However, ectopic expression of CD9 on 3201 cells enhances infection with FIV, suggesting that the role of CD9 may be direct rather than via cellular signalling pathways. These results suggest a novel control point in the lentivirus life-cycle which might be susceptible to modulation by natural antagonists.

Use of a fluorescent probe to assess the activities of candidate agents against intracellular forms of Encephalitozoon microsporidia

Microsporidia are obligate intracellular protozoan parasites. Three species of the genus Encephalitozoon are among the microsporidia that infect immunodeficient humans. These species, Encephalitozoon cuniculi, Encephalitozoon hellem, and Encephalitozoon intestinalis, all develop in a parasitophorous vacuole within a host cell. The present study describes a method that uses the fluorescent probe calcein and confocal microscopy to detect drug-induced effects in Encephalitozoon-infected green monkey kidney cells. The effects were as follows: (i) changes in parasite organization within the parasitophorous vacuole; (ii) swelling and gross morphological changes of parasite developing stages in situ; (iii) killing of developing parasite stages in situ, detected by their uptake of the fluorescent probe; and (iv) reduction in the viability of the host cell population, assessed by the loss of the probe. Verapamil and itraconazole were used to increase the vital dye loading by both uninfected and infected cells. Agents with known antimicrosporidial activity, albendazole and fumagillin, caused all three types of parasite changes at concentrations that had no detectable effect on host cell viability. The effective doses of albendazole and fumagillin that caused swelling and disorganization of parasite developing stages were 5 x 10(-7) and 10(-6) M respectively. Killing of developing stages was detected at 10-fold-higher concentrations for these agents and at 10(-5) M for metronidazole. This method can be used to screen candidate antimicrosporidial agents in infected cultured cells.

ATP-citrate lyase as a target for hypolipidemic intervention. Design and synthesis of 2-substituted butanedioic acids as novel, potent inhibitors of the enzyme

ATP-citrate lyase is the primary enzyme responsible for the synthesis of cytosolic acetyl-CoA in many tissues. Inhibitors of the enzyme represent a potentially novel class of hypolipidemic agent, which are anticipated to have combined hypocholesterolemic and hypotriglyceridemic properties. A series of 2-substituted butanedioic acids have been designed and synthesized as inhibitors of the enzyme. The best compounds, 58, 68, 71, 74 have reversible Ki's in the 1-3 microM range against the isolated rat enzyme. As representative of this compound class, 58, has been shown to exert its inhibitory action through a mainly competitive mechanism with respect to citrate and a noncompetitive one with respect to CoA. None of the inhibitors were able to inhibit cholesterol and/or fatty acid synthesis in HepG2 cells. This has been attributed to the adverse physicochemical properties of the molecules leading to a lack of cell penetration. Despite this, a lead structural class of compound has been identified with the potential for modification into potent, cell-penetrant, and efficacious inhibitors of ATP-citrate lyase.

Engineering enzymes for stability

There have been many recent developments in elaborating the approaches for stabilizing enzymes by stabilizing the folding state, destabilizing the unfolded state and altering the kinetics of unfolding. However, these represent a series of rules of thumb rather than the reliable principles that would be expected of 'engineering'. Stability is taken to include thermodynamic stability as measured by reversible denaturation, and kinetic stability as measured by the unfolding rate for enzymes that are subject to irreversible denaturation. As such, the factors that affect stability of the folded state versus the unfolded state, as well as factors affecting rates of folding and unfolding, all play a role in maintaining stability. Recent studies on the role of kinetics and the effect that site-specific substitutions have on transition-state free energies add to our understanding of the factors that determine whether or not a particular substitution will result in the measurable stabilization of a protein.

Breast screening: a randomised controlled trial in UK general practice of three interventions designed to increase uptake

STUDY OBJECTIVES

To determine the relative effectiveness of three interventions designed to increase the uptake of breast screening.

DESIGN

Randomised controlled trial of a nurse visit with health education (group A), nurse visit without health education (group B), and GP letter (group C).

SETTING

The area of south east London served by the Butterfly Walk Breast Screening Unit in Camberwell.

PARTICIPANTS

Women aged between 50 and 64 years who were registered with 27 GPs in the Lambeth, Southwark and Lewisham family health services authority and who had not attended for first round screening.

MAIN RESULTS

Altogether 799 women were randomly allocated to the three groups. In general, delivering the nurse based interventions proved difficult. In group A, 11.4% (95% CI 7.9, 14.9%) of women subsequently attended for screening compared with 7.8% (95% CI 5.1, 11.4%) in group B and 13.1% (95% CI 7.9, 18.4%) in group C. The differences between the groups (95% CIs) were not statistically significant: A versus C, -1.7% (-8.0, +4.6%); B versus C, -5.3% (-11.3, +0.7%); A versus B, +3.6% (-1.0, +8.2%).

CONCLUSIONS

A personal letter from the GP seems to be at least as effective at increasing the uptake of breast screening in non-attenders as a nurse making a home visit to discuss the issue of breast screening, and is not noticeably less effective than a visit at which a health education intervention is delivered. It is possible that the GP letter is considerably more effective than either of the two interview-based interventions. With regard to implementing strategies which will increase breast screening uptake and are cost effective, further trials of similar minimal interventions in primary care are required.

Perfusion corrections for ultrasonic heating in nonperfused media

The linear bio-heat transfer equation proposed by Pennes is widely used to predict temperature rise in perfused media. In this article, a mathematical relationship between the predicted temperature increase under perfused and nonperfused conditions is derived based on an analysis of the Pennes equation. The perfused temperature at time t and position r, Tperf(r,t) can be calculated from the unperfused temperature history Tunperf(r,t) and the time constant for perfusion, tau: [formula: see text] When the full nonperfused temperature history is not available, a simpler approximate method of estimating the perfused temperature is also suggested, requiring only a knowledge of the time constant for perfusion. Results are given showing the effects of perfusion after different exposure times for a range of beamwidths and perfusion time constants.

Oral health in elderly patients

A study of the oral health of elderly institutionalised patients and their oral care has revealed significant deficiencies, illustrating the need for a multi-disciplinary approach to oral health care centred on the development of mouth care regimens for nursing staff.

Evaluation of the impact of a bedside terminal system in a rapidly changing community hospital

The impact of a bedside terminal system implemented in a community hospital was evaluated using a one-group before-and-after design. Contrary to predictions, the amount of time registered nurses spent in direct care and the positiveness of registered nurses' attitudes toward bedside terminal technology decreased after the implementation. Registered nurse overtime decreased in accordance with the prediction and unit medication errors remained unchanged. The internal validity of these results was threatened by organizational changes that directly and indirectly affected the study unit. Recommendations are made for conducting evaluation research in a rapidly changing hospital environment.

Crystal structure and subunit dynamics of the abalone sperm lysin dimer: egg envelopes dissociate dimers, the monomer is the active species

Lysin is a 16-kD acrosomal protein used by abalone spermatozoa to create a hole in the egg vitelline envelope (VE) by a nonenzymatic mechanism. The crystal structure of the lysin monomer is known at 1.9 A resolution. The surface of the molecule reveals two tracks of basic residues running the length of one surface of the molecule and a patch of solvent-exposed hydrophobic residues on the opposite surface. Here we report that lysin dimerizes via interaction of the hydrophobic patches of monomers. Triton X-100 dissociates the dimer. The crystal structure of the dimer is described at 2.75 A resolution. Fluorescence energy transfer experiments show that the dimer has an approximate KD of 1 microM and that monomers exchange rapidly between dimers. Addition of isolated egg VE dissociates dimers, implicating monomers as the active species in the dissolution reaction. This work represents the first step in the elucidation of the mechanism by which lysin enables abalone spermatozoa to create a hole in the egg envelope during fertilization.