Optimal waveguide dimensions for nonlinear interactions

We investigate strong light confinement in high core-cladding index contrast waveguides with dimensions comparable to and smaller than the wavelength of incident light. We consider oval and rectangular cross sections and demonstrate that an optimal core size exists that maximizes the effective nonlinearity. We also determine that waveguides with asymmetrical cross sections provide the maximum possible nonlinearity, although only a small improvement over the symmetric case. Furthermore, we find that for a specified waveguide shape the largest nonlinearity occurs for nearly the same core area in all cases. Calculations of the dispersion for the optimal-size waveguide at a particular wavelength indicate that the group-velocity dispersion is normal. Ultimately, such designs could be used to develop low-power all-optical devices and to produce waveguides for ultra-low threshold nonlinear frequency generation such as supercontinuum generation.

Cancellous bone changes in the radius of patients with rheumatoid arthritis: a cross-sectional quantitative macroradiographic study

OBJECTIVE

Fractal signature analysis (FSA), a computerized method of textural analysis, permits the separate measurement of changes in vertical and horizontal trabeculae based on the fractal dimension over a range of trabecular widths (fractal signature). We determined whether the FSA of high-definition macroradiographs (x5 magnification) quantified radiographic changes at sites of osteopenia and erosion formation in the rheumatoid arthritis (RA) hand.

METHODS

Sixty-seven RA patients had macroradiographs of the left wrist and hand. The distal radius was scored and grouped from very mild (RA1) to moderate (RA4) disease. Macroradiographs were digitized and FSA of horizontal and vertical trabecular organization was performed in the radius at sites of periarticular osteopenia, erosion formation and at a mid-metaphyseal site. The RA groups were compared with 11 healthy non-arthritic subjects using ANOVA and Dunnett's tests.

RESULTS

Compared to the non-arthritic hands, FSA at the distal radius in groups RA1 to RA4 measured significantly lower (P<0.05) fractal signatures. The fractal signatures were lowest in RA4 involving small, medium to large sized vertical trabeculae at the periarticular osteopenic (0.18 to 0.84 mm, P<0.01) and mid-metaphyseal sites (0.12 to 0.60 and 0.84 to 1.02 mm, P </= 0.04), and small to medium sized vertical trabeculae at the periarticular erosion site (0.24 to 0.84 mm, P<0.01).

CONCLUSION

FSA quantified radiographic bone loss in the distal radius of RA patients with increasing radiographic severity in terms of lower fractal signatures compared with the non-arthritics. Disease-related bone loss was demonstrated by FSA to involve mainly vertical trabeculae at the periarticular osteopenic, periarticular erosion and the mid-metaphyseal sites indicating directionality of bone resorption in RA.

Probing scattering wave functions close to the nucleus

Recently, three-dimensional imaging of the ejected electrons following 100 MeV/amu C6+ single ionization of helium led to the observation of a new structure not predicted by theory [Nature (London) 422, 48 (2003)]]. Instead of the usual "recoil lobe" centered on the momentum-transfer axis, a ring-shaped structure centered on the beam axis was observed. New measurements at 2 MeV/amu exhibit a similar structure, which is now predicted by theory. We argue that the same theory failed at 100 MeV/amu because the faster projectiles probe distances much closer to the nucleus, where our multiple-scattering model is expected to break down.

Classifying client goals in community-based ABI rehabilitation: a taxonomy for profiling service delivery and conceptualizing outcomes

PURPOSE

To develop, confirm and trial a framework for analysing the content of goals set within community-based rehabilitation. This framework (taxonomy) is proposed as a tool to assist in service evaluation and outcome exploration.

METHOD

Qualitative thematic analysis and categorization of 1765 rehabilitation goal statements in a four phase process of synthesis, refinement, verification and application.

RESULTS

A taxonomy of goal content was developed comprising 21 categories within five domains, utilizing 125 descriptors. The taxonomy demonstrated good inter-rater consistency and was able to discriminate between similar but related data sets comprising goal statements.

CONCLUSION

Structured analysis of the content of goal setting (particularly in community rehabilitation) utilizing a framework such as the proposed taxonomy has considerable potential as a 'window' into service delivery to broaden the parameters of existing service evaluation and to more clearly link outcome exploration to intervention.

Angiogenic and immune parameters during recombinant interferon-alpha2b adjuvant treatment in patients with melanoma

As an adjuvant therapy for patients with high risk of recurrent melanoma, high-dose interferon (IFN)-alpha2b therapy has been shown to have some efficacy. We examined 22 patients with resected melanoma who were treated with repeated injections of recombinant IFN-alpha2b during the treatment. Both angiogenic and immune parameters were measured. White blood cells (WBCs) and lymphocyte numbers, lymphocyte subpopulations, serum concentrations of IFN-alpha and anti-IFN-alpha antibodies, and the serum vascular endothelial growth factor (VEGF), interleukin (IL)-8, and basis fibroblast growth factor (bFGF) concentrations were determined over time in resected, recurrence-free patients with American Joint Committee on Cancer (AJCC) stage III melanoma with one or less (LN+ < or = 1, n = 7) or more than one (LN+ > 1, n = 8) lymph nodes involved, and AJCC stage IV resected disease (n = 7). Follow-up and recurrence-free intervals were longer in stage III (LN+ < or = 1) patients compared with stage IV patients (P < 0.05). The number of WBCs and lymphocytes decreased during the treatment for all patient groups (P < 0.001). In addition, percentages of CD8 and CD20 were higher in stage IV patients than in stage III (LN+ > 1) and stage III (LN+ < or = 1) patients at the beginning of therapy (P < 0.05). A significant increase in the percentage of CD20+ cells, mostly B lymphocytes, was observed in the stage III (LN+ > 1) and stage III (LN+ < or = 1) patients over time but not in stage IV patients (P < 0.001). Low IL-8 and bFGF concentrations at the beginning of therapy were associated with significantly longer recurrence-free survival (P < 0.05). These results warrant a larger trial to determine if the differences observed in patients before treatment can provide prognostic markers in patients receiving IFN-alpha2b therapy.

Caregivers of ICU patients discharged home: what burden do they face?

Reforms in healthcare aimed at cost-cutting have led to early hospital discharge for many patients, including those who have sustained critical illness or injury requiring admission to an intensive care unit (ICU). Many former ICU patients experience ongoing health-related problems following discharge from hospital, and need ongoing support and care from their family once discharged. However, family members who take on a caregiving role often experience an enormous burden. The literature has demonstrated the impact of economic, social, physical and psychological factors on those who care for the critically ill following discharge. It is therefore essential that all nurses involved in the ongoing management of ICU patients have an understanding of the caregiving role, and consider both the patient and his/her carer in the discharge planning process. This paper reviews the literature on caregiving, and examines research studies which describe and measure the factors involved in the caregiving role. Although only a small number of studies specifically focus on caregivers of former ICU patients, findings suggest that these caregivers experience a substantial burden which is associated with the complexity of the patient's physical and psychological impairment, and complex technology. To enable nurses to incorporate planning strategies and interventions aimed at minimizing the impact on the caregiver, further research is needed to more fully explore, examine and measure the factors involved in caring for ICU patients post-discharge. Furthermore, ongoing research and evaluation of interventions will build an evidence-base to inform future practice.

Diagnostic procedures for the urogenital system

In making clinical decisions concerning the urogenital system, the emergency department physician has many different diagnostic tools at his or her disposal. Choosing the appropriate diagnostic study can often be difficult. For well over a thousand years, the initial step in assessing almost any urologic condition has been to examine the urine. Thankfully, this has progressed from a gustatory approach to the modern urinalysis. There is certainly a great deal of information that may be gleaned from the urinalysis, but the physician must also be mindful of its limitations. Overuse of the urinalysis can result in unwanted and unhelpful information. Although IVP is still the study of choice in assessing the functional status of the kidney, the introduction of CT and ultrasound technology to clinical medicine has revolutionized the emergency department assessment of the urogenital tract. CT and ultrasound can help differentiate between the urologic emergencies and the various surgical conditions that can mimic them.

Increasing mouthguards usage among junior rugby and basketball players

OBJECTIVE

To evaluate a Western Australian mouthguard promotion campaign, launched at the start of the 1997/98 junior rugby union and junior basketball seasons, aimed at increasing mouthguard usage at competition and training.

METHOD

A quasi-experimental field design was used to assess the impact of the mouthguard campaign on behavioural change. Observational data were collected pre- and post-campaign on mouthguard usage by players present at a rugby and basketball competition event and at a training session. Junior Australian Rules Football players were used as a control group.

RESULTS

Pre-post observational surveys showed a significantly greater increase in mouthguard usage in competition games among rugby union (77% to 84%) and basketball players (23% to 43%) compared with the control group (72% to 73%). All codes showed a post-campaign increase in mouthguard usage at training, but the intervention codes' increases were greater than the control's increase (rugby union: 29% to 40%; basketball: 11% to 36%; football: 34% to 40%).

CONCLUSIONS

The campaign had a significant and substantial effect on behaviour and provides evidence of the benefits of leveraging a sponsorship to modify the behaviour of the target group.

IMPLICATIONS

This campaign provides a model for promoting mouthguard usage in other sports among junior players.

Effects of cyclosporin A administered into the airways against antigen-induced airway inflammation and hyperreactivity in the rat

The immunosuppressant cyclosporin A given orally has anti-asthma properties but carries an undesirable risk of systemic effects. We administered cyclosporin A to Brown Norway rats either orally (p.o.) or topically by intratracheal (i.t.) instillation into the airways before inhaled antigen. Cyclosporin A suppressed the antigen-induced accumulation of activated (CD25+) CD4+ T lymphocytes and eosinophils in the lung, interleukin-5 mRNA expression in lung tissue and airway hyperreactivity. Intratracheal cyclosporin A suppressed cell accumulation at a 10-fold lower dose than that required orally. Minimum effective doses were 3 mg x kg(-1) i.t. and 30 mg x kg(-1) p.o. Intratracheal administration reduced the plasma concentration and systemic exposure compared with an equieffective oral dose, but the reduction (4-5-fold) was not as large as anticipated. Our data suggests that although topical administration to asthmatics would provide some potential for an improved safety margin, it may not offer any major advantage over existing oral therapy. However, the data clearly demonstrate that a novel immunosuppressant with similar anti-inflammatory properties but reduced potential for systemic effects would offer an attractive therapy for severe asthma.

The discovery of RPR 200765A, a p38 MAP kinase inhibitor displaying a good oral anti-arthritic efficacy

RPR132331, a 2-(2-dioxanyl)imidazole, was identified as an inhibitor of tumour necrosis factor (TNF)alpha release from lipopolysaccharide (LPS)-stimulated human monocytes. An intensive programme of work exploring the biology, toxicity and physical chemistry of a novel series of inhibitors, derived from RPR132331, has led to the identification of RPR200765A, a development candidate for the treatment of rheumatoid arthritis (RA). RPR200765A is a potent and selective inhibitor of p38 MAP kinase (IC50 = 50 nM). It inhibits LPS-stimulated TNFalpha release both in vitro, from human monocytes (EC50 = 110 nM), and in vivo in Balb/c mice (ED50 = 6 mg/kg). At oral doses between 10 and 30 mg/kg/day it reduces the incidence and progression in the rat streptococcal cell wall (SCW) arthritis model when administered in either prophylactic or therapeutic dosing regimens. The compound, which is a mesylate salt and exists as a stable monohydrate, shows good oral bioavailabiltiy (F = 50% in the rat) and excellent chemical stability. The data from the SCW disease model suggests that RPR200765A could exhibit a profile of disease modifying activity in rheumatoid arthritis (RA) patients which is not observed with current drug therapies.

Referral to post-acute care following traumatic brain injury (TBI) in the Australian context

The study aimed to describe the types of care allocated at the end of acute care to people diagnosed with TBI and to identify the factors associated with variations in referral to care. A retrospective analysis of medical records of 61 patients was conducted based on a sample from two hospitals. While 60.7% of the study sample were referred to formal rehabilitation care, this was primarily non-inpatient rehabilitation care (32.8%). Discriminant analysis was used to determine medical and non-medical predictors of referral. Results indicated that place of treatment and age contribute to group differences and were significant in separating the inpatient rehabilitation group from the non-inpatient and no rehabilitation groups. Review by a rehabilitation physician was associated with referral to inpatient rehabilitation but was not adequate to explain referral to non-inpatient rehabilitation. An in-depth exploration of post-acute referral is warranted to improve policy and practice in relation to continuity of care following TBI.

Laparoscopic repair of chronic intrathoracic gastric volvulus

BACKGROUND

Totally intrathoracic gastric volvulus is an uncommon presentation of hiatal hernia, in which the stomach undergoes organoaxial torsion predisposing the herniated stomach to strangulation and necrosis. This may occur as a surgical emergency, but some patients present with only chronic, non-specific symptoms and can be treated electively. The aim of this study is to describe a comprehensive approach to laparoscopic repair of chronic intrathoracic gastric volvulus and to critically assess the pre-operative work-up.

METHODS

Eight patients (median age, 71 years) underwent complete laparoscopic repair of chronic intrathoracic gastric volvulus. Symptoms of epigastric pain and early satiety were universally present. Five patients had reflux symptoms. The diagnostic evaluation included a video esophagogram, upper endoscopy, 24-hour pH measurement, and esophageal manometry in all patients. Operative results and postoperative outcome were recorded and follow-up at 1 year included a barium swallow in all patients.

RESULTS

All patients had documented intrathoracic stomach. Five of 8 patients had a structurally normal lower esophageal sphincter. All 4 patients with reflux esophagitis on upper endoscopy had a positive 24-hour pH study, and 2 of these patients had a structurally defective lower esophageal sphincter on manometry. None of the patients had preoperative evidence of esophageal shortening. All procedures were completed laparoscopically. The procedure included reduction of the stomach into the abdomen, primary closure of the diaphragmatic defect, and the construction of a short, floppy Nissen fundoplication. There were no major complications. One patient required repair of a trocar site hernia 6 months postoperatively. At 1-year follow-up, there were no radiologic recurrences of the volvulus. One patient complained of temporary swallowing discomfort and another had recurrent gastroesophageal reflux disease (GERD) symptoms caused by a breakdown of the wrap. All other patients remained asymptomatic during follow-up.

CONCLUSIONS

The repair of chronic gastric volvulus can be accomplished successfully with a laparoscopic approach. A preoperative endoscopy and esophagogram are crucial to detect esophageal stricture or shortening, and manometry is needed to access esophageal motility; pH measurements do not affect operative strategy. The procedure should include a Nissen fundoplication to treat preoperative GERD, to prevent possible postoperative GERD, and to secure the stomach in the abdomen. The procedure is safe but technically challenging, requiring previous laparoscopic foregut surgical expertise.

Effect of the p38 kinase inhibitor, SB 203580, on sephadex induced airway inflammation in the rat

SB 203580 is a pyridinyl imidazole compound which inhibits the release of pro-inflammatory cytokines, such as tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta), in vitro and in vivo by inhibiting p38 mitogen-activated protein kinase (MAPK). The present study investigated the effects of SB 203580 in a model of airway inflammation induced by the topical administration of Sephadex into the rat airways. This inflammatory response is characterized by the development of lung oedema, airway tissue inflammatory cell recruitment and an increase in lung TNF-alpha and IL-1beta levels. Sephadex-induced lung oedema was accompanied by a significant increase in lung tissue TNF-alpha but not IL-1beta levels. There was also a significant increase in lung tissue macrophages and an increase in eosinophils which did not reach significance. SB 203580 administration significantly inhibited lung oedema (ED50=18 mg x kg(-1)) in a dose-related manner but was without significant effect on lung tissue cell recruitment or cytokine levels. These data suggest that the increase in tumour necrosis factor-alpha and lung oedema are separate processes which both contribute to Sephadex pathology. Furthermore, the inhibitory effect of SB 203580 on Sephadex-induced lung oedema suggests that p38 kinase inhibitors may be of use in pulmonary pathologies in which lung oedema is a feature.

Immune alterations in three mouse strains following 2-deoxy-D-glucose administration

Using 2-deoxy-D-glucose (2-DG)-induced stress, our laboratory has developed studies to define stress effects on immune responses. Here, we report effects of increasing doses of 2-DG on the immune response of BALB/c, C57BL/6 and BDF(1) mice 2 h after three injections of 0 to 2000 mg/kg of 2-DG. Female 4- to 5-week-old mice were euthanized and blood and spleens were collected. A suspension of partially purified mature T splenocytes was obtained by negative selection using J11.d2 antibodies. Glucose and corticosterone levels were measured in the plasma of each mouse. Splenocyte and mature T splenocyte suspensions were tested in in vitro proliferation assays with or without concanavalin A. Splenocytes were analyzed for the following cell-surface markers: CD3, TCR alpha/beta, CD4, CD8 and major histocompatibility complex (MHC) Class II. Significant increases in blood glucose levels were observed in C57BL/6 and BALB/c strains with the highest 2-DG dose (p<0.05). Corticosterone levels were higher in BDF(1) mice and C57BL/6 mice following the administration of 1000 and 2000 mg/kg of 2-DG, respectively (p<0.01). In vitro proliferation of mature T splenocytes in the presence of concanavalin A was decreased in BDF(1) (p<0.05) but not in BALB/c and C57BL/6 mice. In addition, in BDF(1) mice the decrease was highly correlated with an increase of CD3+ and TCR alpha/beta+ cells in the spleen. These results demonstrated high variability in the response of different mouse strains to 2-DG-induced stress.

Comparative prevalence of infection with Trichomonas vaginalis among men attending a sexually transmitted diseases clinic

OBJECTIVE

Although established in women as a common cause of vaginal discharge, the prevalence of Trichomonas vaginalis (TV) in men compared with other classic urethral pathogens has not been well characterized. To assess this issue, the authors compared the prevalence of Neisseria gonorrhoeae (GC), Chlamydia trachomatis (CT), and TV in consecutive men attending a sexually transmitted diseases (STD) clinic.

METHODS

From June 1, 1998 to July 27, 1998, 454 consecutive men presenting to the Denver Metro Health Clinic with a new problem were tested for GC by urethral swab culture, for CT by polymerase chain reaction of urine, and for TV by urine sediment culture.

RESULTS

GC, CT, and TV were detected in 23 (5.1%), 34 (7.5%), and 13 (2.8%) of men, respectively. There were significant differences by age for both CT (11.3% in men younger than 30 years versus 3.3% in men 30 years and older, P < 0.05) and TV (0.8% in men younger than 30 years versus 5.1% in men 30 years and older, P < 0.05). In 50 men 30 years or older with symptoms of urethral discharge, TV prevalence (12.0%) rivalled that of GC (12.0%) and CT (14.0%). In 45 men 30 years and older with nongonococcal urethritis, the prevalence of TV and CT were each 13.3%. Multivariate logistical regression analysis showed the presence of discharge and nongonococcal urethritis in men 30 years and older to be an independent predictor of TV.

CONCLUSIONS

TV is common in men attending sexually transmitted disease clinics, especially in those 30 years or older, in whom it may account for as much urethritis as GC or CT. These findings suggest that in older men with nongonococcal urethritis, diagnostic evaluation, empiric treatment, and partner management should include the possibility of TV infection.

Inhibition of interferon, cytokine, and lymphocyte proliferative responses in elite swimmers with altitude exposure

To determine the immunologic consequences of athletic training at altitude, blood samples were taken at rest from 10 swimmers and 8 control nontraining but altitude-exposed members of the 1996 Australian Olympic Swimming Team, near the start and completion of a 21-day training camp at 2102 m. Blood leukocyte numbers dropped in both groups (p < 0.05), with the decrease greater in the swimmers (-38% swimmers, -3% controls). Concanavalin A (ConA)-induced blastogenesis decreased in both groups (p < 0.01), but the drop was greater in the control group (-32% swimmers, -56% controls, p < 0.05). Lipopolysaccharide (LPS)-induced blastogenesis more than doubled in both groups (281% swimmers, 249% controls, p < 0.01). Increases in mitogen-induced interleukin-1beta (IL-1beta), IL-4, and interferon-gamma (IFN-gamma) production and a decrease in IL-2 levels were observed in both groups after altitude exposure (all p < 0.05). The percentage of cells expressing HLA-DR fell (-33% swimmers, -20% controls, p < 0.01), whereas those expressing CD-4 expression increased (16% swimmers only, p < 0.01). Although training at medium-level altitude alters some immunologic parameters, the training-induced changes may be secondary to those induced by altitude alone.

Anti-inflammatory properties of ebselen in a model of sephadex-induced lung inflammation

Ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one), is a seleno-organic compound which protects tissues against oxidative stress. Furthermore, recent data has suggested that this compound possesses a range of anti-inflammatory properties. In this study the authors have investigated the effects of ebselen on Sephadex-induced lung oedema and bronchoalveolar lavage (BAL) tumour necrosis factor (TNF)-alpha and endothelin(ET)-1 levels in rats. Sephadex administration induced lung oedema which was accompanied by an increase in BAL TNF-alpha and ET-1 levels. Ebselen administration (1-30 mg x kg(-1), i.p. at 0, 4 and 12 h post Sephadex) significantly inhibited lung oedema (dose that produced 50% of the maximum inhibition of lung oedema 4.6 mg x kg(-1)) and BAL TNF-alpha levels in a dose-related manner with no effect on ET-1 levels. These data suggest that ebselen may be a useful therapy in lung pathologies in which bronchiolar inflammation is a feature.

Effects of 2-deoxy-D-glucose administration on cytokine production in BDF1 mice

Physical exercise and diet changes have been shown to affect immune parameters, and similar effects are also induced by the administration of a nonmetabolizable glucose analog, 2-deoxy-D-glucose (2-DG). The present study was designed to characterize the effects of glucoprivation induced by 2-DG administration on concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and IL-6 in the blood and interferon-gamma (IFN-gamma), IL-2, and IL-4 in vitro production by partially purified T splenocytes in BDF1 mice. Mice (n = 8 per group) were injected intraperitoneally one or three times with 0, 500, 750, or 1000 mg/kg of 2-DG, and blood and spleens were collected 2 h after the last injection. Partially purified T splenocytes were cultured 24 h in the presence of concanavalin A (ConA). A significant increase in the corticosterone levels with the amount of 2-DG injected was observed after one or three injections (p<0.05). The amount of 2-DG injected was associated with an increase in TNF-alpha, IL-1beta, and IL-6 concentrations in the blood of mice after one or three injections of 2-DG (p<0.05). A significant decrease in in vitro proliferation of partially purified splenocytes in the presence of ConA was associated with a decrease in IFN-gamma production in the culture supernatants and an increase in IL-1 receptor expression on the cell surface (p<0.05).