Exercise for preventing and treating osteoporosis in postmenopausal women

BACKGROUND

Osteoporosis is a condition resulting in an increased risk of skeletal fractures due to a reduction in the density of bone tissue. Prevention of osteoporotic-related fractures is dependent on the ability to detect individuals with low bone mass, including those women who are asymptomatic. Treatment of osteoporosis involves the use of either anti-resorptive (e.g. estrogen and bisphosphonate) or bone formation agents (e.g. fluoride and PTH). The value of exercise as an intervention for the prevention of postmenopausal bone loss is a controversial subject.

OBJECTIVES

To examine the effectiveness of exercise therapy at preventing bone loss and fractures in postmenopausal women.

SEARCH STRATEGY

We searched the Cochrane Musculoskeletal Group's specialised register, MEDLINE, EMBASE, Current Contents and the Cochrane Controlled Trials Registry up to January 2000 according to the methods suggested by Dickersin et al and Haynes et al and the Cochrane Handbook. We hand searched reference lists and consulted content experts.

SELECTION CRITERIA

This review was proceeded by a peer reviewed protocol published in the Cochrane Library. Two reviewers independently selected all randomized controlled trials (RCTs) which met our predetermined inclusion criteria.

DATA COLLECTION AND ANALYSIS

The same two reviewers abstracted the data using predetermined forms and assessed trial quality using a validated assessment tool. For dichotomous outcomes (fractures), relative risks were calculated using fixed effects models. For continuous data, weighted mean differences (WMD) of the percentage change from baseline were calculated. Where heterogeneity existed (determined by a chi square test), a random effects model was used.

MAIN RESULTS

Eighteen randomized controlled trials (RCTs) met the inclusion criteria. The trials had a mean methodological quality score of 2.53. Aerobics, weight bearing and resistance exercises were all effective on the BMD of the spine. The WMD for the combined aerobics and weight bearing program on the spine was 1.79 [95%CI (0.58, 3.01)]. The analyzed results showed walking to be effective on both BMD of the spine 1.31[95%CI (-0.03, 2.65) and the hip 0.92[95%CI (0.21, 1.64). Aerobic exercise was effective in increasing BMD of the wrist 1.22[95%CI (0.71, 1.74)].

REVIEWER'S CONCLUSIONS

Aerobics, weight bearing and resistance exercises are all effective in increasing the BMD of the spine in postmenopausal women. Walking is also effective on the hip. The quality of the reporting of the trials in the meta-analysis was low, in particular, in the areas of allocation concealement and blinding.

Electromagnetic fields for the treatment of osteoarthritis

BACKGROUND

As the focus for osteoarthritis (OA) treatment shifts away from drug therapy, we consider the effectiveness of pulsed electric stimulation which is proven to stimulate cartilage growth on the cellular level.

OBJECTIVES

1)To assess the effectiveness of pulsed electric stimulation for the treatment of osteoarthritis (OA). 2) To assess the most effective and efficient method of applying an electromagnetic field, through pulsed electromagnetic fields (PEMF) or electric stimulation, as well as the consideration of length of treatment, dosage, and the frequency of the applications.

SEARCH STRATEGY

We searched PREMEDLINE, MEDLINE, HealthSTAR, CINAHL, PEDro, and the Cochrane Controlled Trials Register (CCTR) up to and including 2001. This included searches through the coordinating offices of the trials registries of the Cochrane Field of Physical and Related Therapies and the Cochrane Musculoskeletal Group for further published and unpublished articles. The electronic search was complemented by hand searches and experts in the area.

SELECTION CRITERIA

Randomized controlled trials and controlled clinical trials that compared PEMF or direct electric stimulation against placebo in patients with OA.

DATA COLLECTION AND ANALYSIS

Two reviewers determined the studies to be included in the review based on inclusion and exclusion criteria (JH,VR) and extracted the data using pre-developed extraction forms for the Cochrane Musculoskeletal Group. The methodological quality of the trials was assessed by the same reviewers using a validated scale (Jadad 1996). Osteoarthritis outcome measures were extracted from the publications according to OMERACT guidelines (Bellamy 1997) and additional secondary outcomes considered.

MAIN RESULTS

Only three studies with a total of 259 OA patients were included in the review. Electrical stimulation therapy had a small to moderate effect on outcomes for knee OA, all statistically significant with clinical benefit ranging from 13-23% greater with active treatment than with placebo. Only 2 outcomes for cervical OA were significantly different with PEMF treatment and no clinical benefit can be reported with changes of 12% or less.

REVIEWER'S CONCLUSIONS

Current evidence suggests that electrical stimulation therapy may provide significant improvements for knee OA, but further studies are required to confirm whether the statistically significant results shown in these trials confer to important benefits.

Therapeutic ultrasound for the treatment of rheumatoid arthritis

BACKGROUND

Ultrasound is often used, by rehabilitation specialists, as an adjunct therapy for the symptomatic treatment of rheumatoid arthritis (RA). Its mechanical energy has antiinflammatory as well as analgesic properties.

OBJECTIVES

To evaluate the effects of ultrasound on objective and subjective measures of disease activity in patients with RA.

SEARCH STRATEGY

A comprehensive search was conducted up to September 2001 with MEDLINE, EMBASE, PEDro, Current Contents, Sports Discus and CINAHL. The Cochrane Field of Rehabilitation and Related Therapies and the Cochrane Musculoskeletal Review Group specialized registers were also searched. Handsearching was conducted on all retrieved papers and content experts were contacted to identify additional studies.

SELECTION CRITERIA

Comparative controlled studies, such as randomized controlled trials and clinical controlled trials in patients with RA were eligible. No language restrictions were applied. Abstracts were accepted.

DATA COLLECTION AND ANALYSIS

Two independent reviewers identified potential articles from the literature search. These reviewers extracted data using pre-defined extraction forms. Consensus was reached on all the extracted data. Quality was assessed by two reviewers using a 5 point validated assessment tool that measures the quality of randomization, double-blinding and description of withdrawals.

MAIN RESULTS

Two studies (n=80 participants) met the inclusion criteria. Ultrasound to the palmar and dorsal aspect of the hand significantly increases grip strength when compared to a control (weighted mean difference (WMD) 28.07, 95CI: 13.37 to 42.77). Ultrasound to the palmar and dorsal aspects of the hand also appears to have beneficial effects to the following outcome measures: wrist dorsal flexion (WMD 1.90, 95%CI: 0.64 to 3.16), duration of morning stiffness (WMD 28.54, 95%CI: 0.18 to 56.90), number of swollen joints (WMD 1.02, 95%CI: 0.45 to 1.59) and the number of painful joints (WMD 1.20, 95%CI: 0.45 to 1.95). There is no significant difference between a)exercises and wax, b)exercises with ultrasound, c)exercises with ultrasound and faradic hand baths for the following outcome measures: pain score, grip strength, circumference of proximal interphalangeal (PIP) joints, articular index, range of motion or level of activity.

REVIEWER'S CONCLUSIONS

The reviewers concluded that ultrasound in combination with the following treatment modalities; exercises, faradic current and wax baths, is not supported and cannot be recommended. Ultrasound alone can however, be used on the hand to increase grip strength, and to a lesser extent, based on the borderline results, increase wrist dorsal flexion, decrease morning stiffness, reduce the number of swollen joints and reduce the number of painful joints. It is important to note that these conclusions are limited by the methodological considerations such as poor quality of the trials, the low number of clinical trials, and the small sample size of the included studies.

Acupuncture and electroacupuncture for the treatment of RA

BACKGROUND

Acupuncture has been used by rehabilitation specialists as an adjunct therapy for the symptomatic treatment of rheumatoid arthritis (RA). Acupuncture is a traditional Chinese medicine where thin needles are inserted in specific documented points believed to represent concentration of body energies. In some cases a small electrical impulse is added to the needles. Once the needles are inserted in some of the appropriate points, endorphins, morphine-like substances, have been shown to be released in the patient's system, thus inducing local or generalised analgesia.

OBJECTIVES

To evaluate the effects of acupuncture or electroacupuncture on the objective and subjective measures of disease activity in patients with RA.

SEARCH STRATEGY

A comprehensive search was done up to September 2001 with MEDLINE, EMBASE, PEDro, Current Contents, Sports Discus and CINAHL. The Cochrane Field of Rehabilitation and Related Therapies and the Cochrane Musculoskeletal Review Group were also contacted for a search of their specialized registers. Handsearching was conducted on all retrieved papers and content experts were contacted to identify additional studies.

SELECTION CRITERIA

Comparative controlled studies, such as randomized controlled trials and control clinical trials in patients with RA were eligible. No language restrictions were applied. Abstracts were accepted.

DATA COLLECTION AND ANALYSIS

Two independent reviewers identified potential articles from the literature search. These reviewers extracted data using pre-defined extraction forms. Consensus was reached on all the extracted data. Quality was assessed by two reviewers using a five (5) point validated tool that measured the quality of randomization, double-blinding and description of withdrawals.

MAIN RESULTS

Two studies (n=84) met the inclusion criteria. One used acupuncture (~~David 1999~~) while the other used electroacupuncture (~~Man 1974~~). In the first study using acupuncture, no significant difference was found between groups for to erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), the visual analogue scale for pain (VAS P), the visual analogue scale for patient's global assessment (VAS G), the number of swollen joints, the number of tender joints, to the general health questionnaire (GHQ), the score on the modified disease activity scale (DAS) or in the decrease in analgesic intake. In the second study, using electroacupuncture, a significant decrease in knee pain was reported in the experimental group, 24 hours post treatment, when compared to the placebo group (weighted mean difference of -2.0 with 95% CI -3.6,-4.0).

REVIEWER'S CONCLUSIONS

Although the results of the ~~Man 1974~~ study show that electroacupuncture may be beneficial to reduce symptomatic knee pain in patients with RA 24 hours post treatment, the reviewers concluded that the poor quality of the trial, including the small sample size proclude its recommendation. The reviewers further conclude that acupuncture has no effect on ESR, CRP, pain, patient's global assessment, number of swollen joints, number of tender joints, general health, disease activity and reduction of analgesics. These conclusions are limited by methodological considerations such as the type of acupuncture (acupuncture vs electroacupuncture), the site of intervention, the low number of clinical trials and the small sample size of the included studies.

Elucidation of solvent exposure, side-chain reactivity, and steric demands of the trifluoromethionine residue in a recombinant protein

When incorporated into proteins, fluorinated amino acids have been utilized as 19F NMR probes of protein structure and protein-ligand interactions, and as subtle structural replacements for their parent amino acids which is not possible using the standard 20-amino acid repertoire. Recent investigations have shown the ability of various fluorinated methionines, such as difluoromethionine (DFM) and trifluoromethionine (TFM), to be bioincorporated into recombinant proteins and to be extremely useful as 19F NMR biophysical probes. Interestingly, in the case of the bacteriophage lambda lysozyme (LaL) which contains only three Met residues (at positions 1, 14, and 107), four 19F NMR resonances are observed when TFM is incorporated into LaL. To elucidate the underlying structural reasons for this anomalous observation and to more fully explore the effect of TFM on protein structure, site-directed mutagenesis was used to assign each 19F NMR resonance. Incorporation of TFM into the M14L mutant resulted in the collapse of the two 19F resonances associated with TFM at position 107 into a single resonance, suggesting that when position 14 in wild-type protein contains TFM, a subtle but different environment exists for the methionine at position 107. In addition, 19F and [1H-13C]-HMQC NMR experiments have been utilized with paramagnetic line broadening and K2PtCl4 reactivity experiments to obtain information about the probable spatial position of each Met in the protein. These results are compared with the recently determined crystal structure of LaL and allow for a more detailed structural explanation for the effect of fluorination on protein structure.

Reactivity of free radicals on hydroxylated quartz surface and its implications for pathogenicity experimental and quantum mechanical study

We studied the adsorption of hydroxyl radicals and superoxide anion radicals on a hydroxylated alpha-quartz surface using cluster and periodic slab models by means of density functional calculations. Models of two hydroxylated alpha-quartz surfaces--(0001) and (0111)--have been used in the simulations. The hydroxyl radical adsorbs readily on both surfaces. The subsurface Si-O bonds are weakened during the adsorption resulting in surface layer destabilization. This destabilization leads directly to surface disintegration in the case of *OH/(0111) adsorption. The product of the surface disintegration and reconstruction is a surface terminated by silanol groups (Si-OH) and siloxyl radicals (Si-O*). The model calculations suggest that adsorption of *OH on a hydroxylated quartz surface transforms a chemically inert, aged, silanol terminated surface to a very reactive, silicon-based radical terminated surface. The activated surface may then cause oxidative damage to the adsorbed biomaterial. The superoxide anion radical adsorbs on both surfaces, but the adsorption products are only weakly bonded to the surface. The calculated energy barrier for the O2*- activated subsurface Si-O bond dissociation is 10 kcal/mol, which is higher than for the *OH activated process (4 kcal/mol). The calculated weaker bonding to the surface and higher activation energy barrier suggest that the superoxide anion radical will be less efficient in reactivation of an aged, hydroxylated quartz surface than the hydroxyl radical. The importance of the specific geometry of the surface silicon atoms on the surface reactivity and adsorption properties is also discussed. The theoretical predictions are supported experimentally using chemiluminescence to monitor reactivation of the aged silica surface by superoxide anion radicals.

Screening from a subtracted embryonic chick hindbrain cDNA library: identification of genes expressed during hindbrain, midbrain and cranial neural crest development

The vertebrate hindbrain is segmented into a series of transient structures called rhombomeres. Despite knowing several factors that are responsible for the segmentation and maintenance of the rhombomeres, there are still large gaps in understanding the genetic pathways that govern their development. To find previously unknown genes that are expressed within the embryonic hindbrain, a subtracted chick hindbrain cDNA library has been made and 445 randomly picked clones from this library have been analysed using whole mount in situ hybridisation. Thirty-six of these clones (8%) display restricted expression patterns within the hindbrain, midbrain or cranial neural crest and of these, twenty-two are novel and eleven encode peptides that correspond to or are highly related to proteins with previously uncharacterised roles during early neural development. The large proportion of genes with restricted expression patterns and previously unknown functions in the embryonic brain identified during this screen provides insights into the different types of molecules that have spatially regulated expression patterns in cranial neural tissue.

Therapeutic ultrasound for treating patellofemoral pain syndrome

BACKGROUND

Therapeutic ultrasound is one of several rehabilitation interventions suggested for the management of pain due to patellofemoral pain syndrome.

OBJECTIVES

To assess the effectiveness and side effects of ultrasound therapy for treating patellofemoral pain syndrome.

SEARCH STRATEGY

We searched MEDLINE, Embase, Healthstar, Sports Discus, CINAHL, the Cochrane Controlled Trials Register, the PEDro database, the specialized registry of the Cochrane musculoskeletal group and the Cochrane field of physical and related therapies up to December 2000 according to the sensitive search strategy for RCTs designed for the Cochrane Collaboration. The search was complemented with handsearching of the reference lists. Key experts in the area were contacted for further articles.

SELECTION CRITERIA

All randomized controlled trials (RCTs) and controlled clinical trials (CCTs), case-control and cohort studies comparing therapeutic ultrasound against placebo or another active intervention in patients with patellofemoral pain syndrome were selected, according to an a priori protocol.

DATA COLLECTION AND ANALYSIS

Two reviewers determined the studies to be included based on a priori inclusion criteria (LB, VAR). Data were independently abstracted by the same two reviewers, and checked by a third reviewer (BS) using a pre-developed form. The same two reviewers, using a validated scale, independently assessed the methodological quality of the RCTs and CCTs. The data analysis was performed using Peto Odds ratios.

MAIN RESULTS

The search retrieved 85 articles. Of the 8 that were potentially relevant, only one RCT, including 53 patients with patellofemoral pain syndrome, was included. All patients received exercises as a concurrent therapy. Ultrasound combined with ice massage contrast (n=13) was not statistically different from ice massage alone (n=16) in terms of patient-rated pain relief improvement, quadriceps and hamstring strength. In the ultrasound and ice massage group, 46% (6/13) reported improved pain relief compared to 31% (4/13) in the ice massage alone group. This difference of 15% does not meet international standards for clinically important improvement in osteoarthritis of 20%. Side effects were not reported.

REVIEWER'S CONCLUSIONS

Ultrasound therapy was not shown to have a clinically important effect on pain relief for patients with patellofemoral pain syndrome. These conclusions are limited by the poor reporting of the therapeutic application of the ultrasound and low methodological quality of the trial included. No conclusions can be drawn concerning the use or non use of ultrasound for treating patellofemoral pain syndrome. More well-designed studies are needed.

Comparative analysis of embryonic gene expression defines potential interaction sites for Xenopus EphB4 receptors with ephrin-B ligands

The Eph family of receptor tyrosine kinases and their ligands, the ephrins, act as signaling molecules regulating the migratory behavior of neurons and neural crest cells, and are implicated in tissue patterning, blood vessel formation, and tumorigenesis. On the basis of structural similarities and overlapping binding specificities, Eph receptors as well as their ligands can be divided into A and B subfamilies with orthologues found in all vertebrates. We describe here the isolation of cDNAs encoding Xenopus EphB4 receptors and show that embryonic expression is prominently associated with the developing vasculature, newly forming somites, the visceral arches, and non-neuronal tissues of the embryonic head. In a screen to identify potential ligands for EphB4 in Xenopus embryos, we isolated cDNAs for the Xenopus ephrin-B2 and -B3, which demonstrates that the Xenopus genome harbors genes encoding orthologues to all three currently known mammalian ephrin-B genes. We next performed in situ hybridizations to identify tissues and organs where EphB4 receptors may encounter ephrin-B ligands during embryonic development. Our analysis revealed distinct, but overlapping patterns of ephrin-B gene expression. Interestingly, each ephrin-B ligand displayed expression domains either adjacent to or within EphB4-expressing tissues. These findings indicate that EphB4 receptors may interact in vivo with multiple B-class ephrins. The expression patterns also suggest that EphB4 receptors and their ligands may be involved in visceral arch formation, somitogenesis, and blood vessel development.

In vivo cell sorting in complementary segmental domains mediated by Eph receptors and ephrins

The restriction of intermingling between specific cell populations is crucial for the maintenance of organized patterns during development. A striking example is the restriction of cell mixing between segments in the insect epidermis and the vertebrate hindbrain that may enable each segment to maintain a distinct identity. In the hindbrain, this is a result of different adhesive properties of odd- and even-numbered segments (rhombomeres), but an adhesion molecule with alternating segmental expression has not been found. However, blocking experiments suggest that Eph-receptor tyrosine kinases may be required for the segmental restriction of cells. Eph receptors and their membrane-bound ligands, ephrins, are expressed in complementary rhombomeres and, by analogy with their roles in axon pathfinding, could mediate cell repulsion at boundaries. Remarkably, transmembrane ephrins can themselves transduce signals, raising the possibility that bi-directional signalling occurs between adjacent ephrin- and Eph-receptor-expressing cells. We report here that mosaic activation of Eph receptors leads to sorting of cells to boundaries in odd-numbered rhombomeres, whereas mosaic activation of ephrins results in sorting to boundaries in even-numbered rhombomeres. These data implicate Eph receptors and ephrins in the segmental restriction of cell intermingling.

The Nuclear Receptor Resource: a growing family

Last year, the original Glucocorticoid Receptor Resource was expanded into a comprehensive project: the Nuclear Receptor Resource (NRR, http:// nrr.georgetown.edu/nrr/nrr.html ). The NRR has since been offering comprehensive information on nuclear receptor structure and function, as well as general facts of interest to the scientific community on meetings, funding and employment opportunities. The project now includes individual resources as part of a network which integrates information on glucocorticoid, androgen, mineralocorticoid, thyroid hormone, Vitamin D and peroxisome-proliferator activated receptors. Many investigators have joined the NRR network by filling the Who is who? form available in the NRR home page. This has facilitated communication among scientists in the field and dissemination of data nor otherwise published. Because several investigators have contacted NRR authors over the past few months asking for advice and materials for educational purposes, we have recently decided to include in our project an educational resource on nuclear receptors termed the 'Graphics Library'. The input and suggestions of NRR users do shape the future direction of the project, so we encourage user to give us feedback.

Roles of Eph receptors and ephrins in neural crest pathfinding

Neural crest cells migrate along specific pathways to their destinations and, like neuronal growth cones, must be guided by extracellular cues. One example of neural crest pathfinding is the segmental migration of branchial and trunk neural crest; this is associated with the patterning of the skeletal components of the branchial arches and of the peripheral nervous system. In this review, we discuss recent work that has implicated Eph receptors and their ephrin ligands in mediating repulsive interactions that restrict neural crest cell migration. We relate these findings to the roles of these receptors and ligands in growth cone guidance and the segmental restriction of cell movement in the hindbrain.

The EphA4 and EphB1 receptor tyrosine kinases and ephrin-B2 ligand regulate targeted migration of branchial neural crest cells

BACKGROUND

During vertebrate head development, neural crest cells migrate from hindbrain segments to specific branchial arches, where they differentiate into distinct patterns of skeletal structures. The rostrocaudal identity of branchial neural crest cells appears to be specified prior to migration, so it is important that they are targeted to the correct destination. In Xenopus embryos, branchial neural crest cells segregate into four streams that are adjacent during early stages of migration. It is not known what restricts the intermingling of these migrating cell populations and targets them to specific branchial arches. Here, we investigated the role of Eph receptors and ephrins-mediators of cell-contact-dependent interactions that have been implicated in neuronal pathfinding-in this targeted migration.

RESULTS

Xenopus EphA4 and EphB1 are expressed in migrating neural crest cells and mesoderm of the third arch, and third plus fourth arches, respectively. The ephrin-B2 ligand, which interacts with these receptors, is expressed in the adjacent second arch neural crest and mesoderm. Using truncated receptors, we show that the inhibition of EphA4/EphB1 function leads to abnormal migration of third arch neural crest cells into second and fourth arch territories. Furthermore, ectopic activation of these receptors by overexpression of ephrin-B2 leads to scattering of third arch neural crest cells into adjacent regions. Similar disruptions occur when the expression of ephrin-B2 or truncated receptors is targeted to the neural crest.

CONCLUSIONS

These data indicate that the complementary expression of EphA4/EphB1 receptors and ephrin-B2 is involved in restricting the intermingling of third and second arch neural crest and in targeting third arch neural crest to the correct destination. Together with previous work showing that Eph receptors and ligands mediate neuronal growth cone repulsion, our findings suggest that similar mechanisms are used for neural crest and axon pathfinding.

A marker of terminal stalk cell terminal differentiation in Dictyostelium

We describe the isolation of staB, a Dictyostelium gene that is selectively expressed in stalk cells. If an aggregate enters culmination immediately staB is expressed in the bottom half of the stalk and in the basal disc but if a migratory slug is formed it is also expressed in the top of the stalk and in a disc of cells that surmounts the spore head. The latter two populations of cells derive from the rear part of the prestalk region, the pstO cells, which would therefore seem to change their transcriptional competency during slug migration. The staB promoter contains a distal region that is required for expression within both the stalk and the basal disc and a proximal region that is required only for expression within the basal disc. This uncoupling of transcriptional specificities suggests that the signalling mechanisms that direct terminal differentiation in these two tissues differ in some way.

Incorporation of trifluoromethionine into a phage lysozyme: implications and a new marker for use in protein 19F NMR

Much interest is currently focused on understanding the detailed contribution that particular amino acid residues make in protein structure and function. Although the use of site-directed mutagenesis has greatly contributed to this goal, the approach is limited to the standard repertoire of twenty amino acids. Fluorinated amino acids have been utilized successfully to probe protein structure and dynamics as well as point to the importance of specific residues to biological function. In our continuing investigations on the importance of the amino acid methionine in biological systems, the successful incorporation of L-S-(trifluoromethyl)homocysteine (L-trifluoromethionine; L-TFM) into bacteriophage lambda lysozyme (LaL), an enzyme containing three methionine residues, is reported. The L isomer of TFM was synthesized in an overall yield of 33% from N-acetyl-D,L-homocysteine thiolactone and trifluoromethyl iodide. An expression plasmid giving strong overproduction of LaL was prepared and transformed into an Escherichia coli strain auxotrophic for methionine permitting the expression of LaL in the presence of L-TFM. The analogue would not support growth of the auxotroph and was found to be inhibitory to cell growth. However, cells that were initially grown in a Met-rich media followed by protein induction under careful control of the respective concentrations of L-Met and L-TFM in the media, were able to overexpress TFM-labeled LaL (TFM-LaL) at both high (70%) and low (31%) levels of TFM incorporation. TFM-LaL at both levels of incorporation exhibited analogous activity to the wild type enzyme and were inhibited by chitooligosaccharides indicating that incorporation of the analogue did not hinder enzyme function. Interestingly, the 19F solution NMR spectra of the TFM-labeled enzymes consisted of four sharp resonances spanning a chemical shift range of 0.9 ppm, with three of the resonances showing very modest shielding changes on binding of chitopentaose. The 19F NMR analysis of TFM-LaL at both high and low levels of incorporation suggested that one of the methionine positions gives rise to two separate resonances. The intensities of these two resonances were influenced by the extent of incorporation which was interpreted as an indication that subtle conformational changes in protein structure are induced by incorporated TFM. The similarities and differences between Met and TFM were analyzed using ab initio molecular orbital calculations. The methodology presented offers promise as a new approach to the study of protein-ligand interactions as well as for future investigations into the functional importance of methionine in proteins.

The Nuclear Receptor Resource Project

We have expanded the original Glucocorticoid Receptor Resource (GRR) database to include several individual resources as part of a larger project called the Nuclear Receptor Resource (NRR). In addition to the GRR, the NRR currently features the Thyroid Hormone Receptor Resource, the Androgen Receptor Resource, the Mineralocorticoid Receptor Resource, the Vitamin D Receptor Resource, and the Steroid Receptor Associated Proteins Resource. The goal of the NRR project is to provide a comprehensive resource for information on the nuclear receptor superfamily, and to provide a forum for the dissemination and discussion of both published and unpublished material on these proteins. Although the individual resources are managed from different servers, all the files are integrated and can be accessed through the project's Home Page, housed at http://nrr. georgetown.edu/nrr.html. In the near future, we hope to expand the project to contain information on other nuclear receptors and to better our electronic publication system. To accomplish this, we encourage the involvement of nuclear receptor investigators in the NRR.

The duration of infection modifies mitochondrial oxidative capacity in rat skeletal muscle

Sepsis increases phosphocreatine (PCr) breakdown and reduces PCr stores in skeletal muscle. To determine if systemic infection impairs mitochondrial function, in vivo 13P magnetic resonance spectroscopy (31P MRS) studies of the gastrocnemius muscle were performed in virus-free male Wistar rats 24 or 48 hr after cecal ligation and 18-gauge needle single puncture (24 degrees CLP, n = 16; 48 degrees CLP, n = 15) or sham operation (24 degrees SHAM, n = 18; 48 degrees SHAM, n = 13). Physiologic saline (6 ml/100 g body wt) was injected intraperitoneally for fluid resuscitation. Water but no food was allowed in all animals. High resolution (8.45 Tesla) 31P MRS spectra, obtained at rest and during exercise using a 1.4-cm surface coil, were used to calculate PCr/ATP, PCr/P(i) ratios, and intracellular pH. Steady-state muscle exercise was induced by supramaximal sciatic nerve stimulation at 10 Hz for 10 min. Recovery of PCr/(PCr + P(i)) ratios after exercise was fitted to a monoexponential curve. The resultant function was used to calculate the half time for PCr recovery, the initial PCr resynthesis rate, and the maximal oxidative ATP synthesis rate, which reflect the rephosphorylation of ADP and are therefore measures of mitochondrial oxidative capacity. PCr/ATP ratios decreased by 12 and 11%, 24 and 48 hr after CLP, respectively. The PCr/P(i) ratios decreased incrementally (7% in 24 degrees CLP vs 23% in 48 degrees CLP animals). Twenty-four hours after operation the half time for PCr recovery was shortened while the initial PCr resynthesis rate and maximal oxidative ATP synthesis rate were accelerated in CLP animals compared to controls.(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose and function of humor in OR nursing

1. Laughter has always echoed throughout the halls and rooms of hospitals. The latest jokes and the funniest stories are heard in the OR department; from there come some of the funniest "dumb student" stories; macabre practical jokes; stories and jokes about surgeon/anesthesiologist/nurse relationships; and jokes, cartoons, and get-well cards that reveal patients' greatest anxieties and fears about surgery and the operating room. 2. Humor as an indirect form of communication (verbal or non-verbal) has many sociologic and psychologic purposes. Also, humor enhances learning, and stimulates alertness and creativity. The resulting laughter produces a positive physiologic change in the body. 3. Humor and laughter are healthy therapeutic tools we must value, learn to cultivate, and add to our professional and personal lives. However, there is still a need for more research on how to use humor therapeutically, especially in OR nursing.

Monoclonal antibodies recognising stage and region specific epitopes in embryonic mouse palatal epithelial cells

Four monoclonal antibodies raised against murine embryonic palatal epithelium were used to stain frontal cryosections of embryonic mouse heads (d 11-15). One antibody (6A11) recognised the nasal epithelium at the angle of the palate prior to shelf elevation (embryonic d 11-d 13) and the epithelia at the tips of the approximated shelves (embryonic d 14.5). Two further antibodies (2H6 and 3H2) recognised epitopes on the entire palatal epithelium until shelf elevation (embryonic d 14.5) when their expression ceased. The epitope recognised by antibody 6D3 was absent from the palatal epithelium until embryonic d 13 when it displayed region specific expression, being present on the nasal aspect in the midpalate and the tip of the palate posteriorly. On embryonic d 14.5 staining of the medial edge epithelia was present in all regions. Whilst the nasal palatal epithelium stained in the anterior and mid regions, only patchy staining of the oral epithelium was detected. By embryonic d 15 staining was present throughout the palatal epithelia. These antibodies are directed against intracellular epitopes, possibly keratins. Indeed, immunoblotting assays revealed that antibody 2H6 recognised keratin 18. The developmental regulation of the epitopes recognised by the antibodies corresponds with differentiative events occurring during murine palatogenesis.