Does cardiopulmonary bypass still represent a good investment? The biomaterials perspective

Cardiopulmonary (CPB) bypass is 50 years old this year, and has undergone considerable change in that time, particularly with regard to developing technology. However, in recent years the routine application of CPB, as the treatment of choice for patients undergoing reparative heart surgery, has been challenged by new, evolving techniques, particularly Off-Pump Coronary Artery Bypass (OPCAB) and stenting. This paper considers whether CPB still represents a sound investment prospect, with particular emphasis on the biomaterial developments currently taking place. Whilst we accept that routine application of CPB is shrinking under pressure from less invasive techniques, we suggest that this may represent an opportunity to deliever a more highly evolved perfusion to the core of very sick and complex patients who may not be suitable candidates for OPCAB or stenting. These patients will benefit from the application of new technologies currently under development, such as smaller perfusion circuits, improved biomaterial surfaces, smart membranes, and biosensor technology, all aimed at making clinical perfusion a safer and more predictable procedure for the patient. All things conssidered, we feel that CPB, although shrinking in absolute size, still represents a good investment.

The influence of different dressings on the pH of the wound environment

OBJECTIVE

This study examines the effect of various wound dressings on the pH levels of a wound, using a simulated wound environment.

METHOD

The pH levels of a 4 different wound dressings (manuka honey dressing, sodium carboxymethylcellulose hydrofiber dressing, polyhydrated ionogen-coated polymer mesh dressing, and a protease modulating collagen cellulose dressing) were tested in a simulated horse serum wound environment. The effect of local buffering was observed and pH changes in real time were measured.

RESULTS

All dressings were found to have low pH (below pH 4), with the lowest being the protease modulating collage cellulose dressing, with a pH of 2.3. The dressing with the strongest acid concentration was the polyhydrated, ionogen-coated, polymer mesh dressing.

CONCLUSION

The low pH and strong acidic nature of the dressing investigated indicate that they may play a role in influencing the healing process in a wound.

DECLARATION OF INTEREST

The authors have no conflicts of interest to declare. This study was funded by the EPSRC.

Recollected experiences of first hospitalisation for acute psychosis among persons diagnosed with schizophrenia in South Africa

<p>First-time admission to a psychiatric hospital for acute psychosis has been reported to be extremely traumatic, and this has not been adequately researched in the South African context. This study approached persons diagnosed with schizophrenia and explores their recollected, subjective experiences of their first admission to a South African psychiatric hospital ward for acute psychosis. Semi-structured individual interviews were conducted with seven participants diagnosed with schizophrenia. These were analysed using thematic content analysis. While some participants had positive experiences, the majority reported frightening, distressing, emotionally painful or traumatic experiences during their first hospitalisation. The first hospital admission was also described as having serious long-term implications for the person’s wellbeing, particularly as the diagnosis of schizophrenia made them feel isolated and stigmatised, which further hinders them from recovering from their symptoms and reintegrating into society. This study therefore draws attention to aspects of the process of first admission to psychiatric wards in South Africa, which may benefit from proactive intervention and closer research attention.</p>

Kinetics of transient hiatus hernia during transient lower esophageal sphincter relaxations and swallows in healthy subjects

BACKGROUND

Proximal displacement of the gastro-esophageal junction (GEJ) is present in hiatus hernia but also occurs transiently during transient lower esophageal sphincter relaxations (TLESRs) and swallows. Using a novel magnetic-based technique we have performed detailed examination of the GEJ movement during TLESRs and swallows in healthy subjects.

METHODS

In 12 subjects, a magnet was endoscopically clipped to the GEJ and combined assembly of Hall-Effect locator probe and 36 channel high-resolution manometer passed nasally. After a test meal the subjects were studied for 90 min.

KEY RESULTS

The median amplitude of proximal movement of GEJ during TLESRs was 4.3 cm (1.6-8.8 cm) and this was substantially greater than during swallowing at 1.2 cm (0.4-2.7 cm), P = 0.002. With both TLESRs and swallows proximal GEJ movement coincided with lower esophageal sphincter (LES) relaxation and return to its original position occurred 4 s after return of LES tone. Kinetic modeling of the movement of the GEJ during TLESRs indicated two return phases with the initial return phase having the greater velocity (0.9 cm s(-1) ) and being strongly correlated with amplitude of proximal movement (r = 0.8, P < 0.001).

CONCLUSIONS & INFERENCES

The marked proximal GEJ migration during TLESRs represents very severe herniation of the GEJ. The rapid initial return of the GEJ following TLESRs when the crural diaphragm is relaxed and its correlation with amplitude suggest it is due to elastic recoil of the phreno-esophageal ligament. The marked stretching of the phreno-esophageal ligament during TLESRs may contribute to its weakening and development of established hiatus hernia.

Whole body MRI in the diagnosis of chronic recurrent multifocal osteomyelitis

Chronic recurrent multifocal osteomyelitis (CRMO) is a diagnosis of exclusion primarily in children and adolescents. As part of the essential criteria for the diagnosis of CRMO, multifocal lesions must be identified. We present the case of an 11-year-old boy with CRMO, whose diagnosis was facilitated by the use of whole body magnetic resonance imaging (WBMR), but not isotope bone scanning.

High-resolution esophageal manometry: addressing thermal drift of the manoscan system

BACKGROUND

The high resolution esophageal manometry system manufactured by Sierra Scientific Instruments is widely used. The technology is liable to 'thermal drift', a change in measured pressure due to change in temperature. This study aims to characterize 'thermal drift' and minimize its impact.

METHODS

Response of the system to immediate temperature change (20 °C to 37 °C) was tested. Accuracy of pressure measurement over two hours at 37 °C was examined. Six repetitions were performed and median pressure change calculated for each sensor. Sensors were compared using Kruskal-Wallis test. Current correction processes were tested.

KEY RESULTS

There was a biphasic response of the system to body temperature: an immediate change in recorded pressure, 'thermal effect' and an ongoing pressure change with time, 'baseline drift'. Median thermal effect for all 36 sensors was 7 mmHg (IQR 3.8 mmHg). Median baseline drift was 11.1 mmHg (IQR 9.9 mmHg). Baseline drift varied between sensors but for a given sensor was linear. Interpolated thermal compensation, recommended for prolonged studies, corrects data assuming a linear drift of pressures. When pressures were corrected in this way, baseline pressure was almost restored to zero (Median 0.3 mmHg, IQR 0.3). The standard thermal compensation process did not address the error associated with baseline drift.

CONCLUSIONS & INFERENCES

Thermal effect is well compensated in the current operation of the system but baseline drift is not well recognized or addressed. Incorporation of a linear correction into current software would improve accuracy without impact on ease of use.

Current issues in coronary stent technology

Coronary artery stents have become the medical device of choice for the treatment of coronary artery disease. Since their introduction in 1987, significant advances in stent technology have taken place. A major objective of these developments was the reduction of in-stent restenosis, the formation of neointimal tissue inside the stent triggered by vessel injury and the inflammatory response, which results in renarrowing of the coronary artery. Improvements in strut configuration, thickness, and materials have enhanced deliverability and reduced vessel damage. Currently available drug-eluting stents release drugs that reduce neointimal formation through the arrest of cell proliferation. Drug-eluting stents have significantly reduced rates of in-stent restenosis. However, concerns have been raised with respect to their long-term safety, particularly in relation to the occurrence of late thrombosis. The post-procedural monitoring of stent-related complications is also of interest, including the relative suitability of invasive techniques such as angiography and intravascular ultrasound, and non-invasive techniques such as computed tomography and magnetic resonance imaging scanning. This paper reviews the current issues in stent technology.

Elimination of false-positive Histoplasma antigenemia caused by human anti-rabbit antibodies in the second-generation Histoplasma antigen assay

False-positive Histoplasma antigenemia was reported in solid organ allograft recipients who had received rabbit anti-thymocyte globulin (RATG, RATG) caused by human anti-rabbit antibodies (HARA). A second-generation Histoplasma antigen detection assay was developed to overcome false positivity caused by HARA. With the second-generation assay, false-positive results were eliminated in 18 of 19 cases without reduction in the sensitivity in patients with histoplasmosis. In fact, sensitivity for detection of antigenuria in patients with acquired immunodeficiency syndrome and disseminated histoplasmosis was higher in the second-generation assay. Physicians should be aware of the potential for false-positive results in sandwich immunoassays in specimens from patients who have received RATG.

Central dose data management and analysis in IT-driven radiation protection strategies

The applications of information technology in health care are now widespread and continue to grow. Medical imaging is at the forefront of this revolution and the introduction of digital detection methods to replace film is now addressing the diagnostic X-ray market, the most routinely employed imaging modality. The introduction of picture archiving and communication systems, hospital and radiology information systems is well underway, and the integration of radiation protection initiatives into these developments is desirable. In north-west UK, a project aimed at developing and implementing IT-driven radiation protection strategies has been underway for the past 10 y. Such strategies are geared towards the support of European Commission patient dose directive 97/43 EURATOM, in particular the need to implement clinical audit, patient dose audit and to establish dose reference levels. This paper demonstrates the national and local requirements for establishing a central dose data management system for use in radiation protection strategies. In particular, such a system can help develop and support the role of a medical physics expert in optimisation. The scientific requirements for such an approach are presented in this paper, and a prototype system is described. Preliminary results obtained with the central data management facility are also presented and the implication for analysing multiple site dose data in optimisation strategies for digital radiographic technology is highlighted.

False-positive Histoplasma antigenemia caused by antithymocyte globulin antibodies

False-positive Histoplasma antigen results were identified in two patients who received rabbit antithymocyte globulin (ATG, Thymoglobulin(R)) to prevent allograft rejection. To determine the prevalence of false-positive results following the administration of Thymoglobulin, sequential specimens were tested from a cohort of transplant recipients. Of 107 such patients, 17 (15.9%) demonstrated false-positive tests for Histoplasma antigenemia. False antigenemia peaked at 2-4 weeks after ATG administration and cleared over the next few months. Physicians should be aware of the potential for false-positive results in specimens from patients who have received ATG.

Speed and spinal injuries

Road traffic accidents (RTA) are a significant cause of spinal trauma. On the 31st of October 2002 a new penalty system for speed related driving offences was introduced in Ireland. Our intention was to assess the effects of the introduction of this system on the activity of the National Spinal Injuries Centre (NSIC) with a retrospective review of all admissions from November 1998 until October 2003. The number of new acute admissions to the spinal injury unit during the study period was 831. In the first 6 months of the new system the number of RTA related admissions fell significantly to 17 compared to an average of 33 in the preceding 4 years. However, this effect was not maintained in the second 6 months. The fall in spinal injuries following RTA in the first 6 months of the new system parallels the pattern of road death reduction in this period. This suggests that driving behaviour can be modified with direct benefits in reducing spinal injuries. However, this effect has not persisted in the second 6 months of the new system suggesting that to maintain this change the perception and familiarity of a penalty are important factors in its impact.

Retrospective review of outcome post open reduction and K-wire fixation for grade III acromioclavicular joint subluxations

There is controversy about the therapy for grade III acromioclavicular dislocation according to Tossy and Rockwood's classification. We identified 25 patients who underwent acromioclavicular joint wiring for grade III subluxations under the care of a single consultant in the last 5-year period. All patients were asked to fill in a DASH (Disabilities of the Arm, Shoulder and Hand) questionnaire to assess outcome following acromioclavicular joint repair, and their clinical notes were reviewed. Our results show that open reduction and Kirschner- (K) wire fixation of grade III AC joint disruptions results in good strength and range of motion of the affected shoulder. It is associated with DASH scores, which are comparable to those of the general population for the same age, indicating little residual disability. All patients returned to their pre-injury occupation, and all but one returned to previous sporting activities. Complications occurred in four patients, but only one required K-wire repositioning.

Effects of CD4 and CD8 T lymphocyte depletion on the course of histoplasmosis following pulmonary challenge

Use of a pulmonary model of histoplasmosis in CD4/CD8 lymphocyte depleted animals offers an opportunity to study pathogenesis in a setting resembling AIDS. Flow cytometric analysis demonstrated that administration of anti-CD4 and anti-CD8 antibodies reduced CD4 and CD8 T cell subsets in the lungs, lymph nodes and spleen. Depletion of these cells transformed the infection from a self-limited course in normal mice to a progressive, fatal course in CD4/CD8 depleted mice. CD4 depletion alone had a lesser effect on survival, but increased fungal burden, while CD4/CD8 depletion had the greatest effect. Histopathologic studies showed marked differences in the inflammatory response between the dually depleted animals and the non-depleted controls. In conclusion, the course of histoplasmosis in CD4/CD8 depleted animals is progressive and fatal, resembling that observed in immunosuppressed patients. This model appears suitable for investigation of immunity to H. capsulatum, and should be useful for evaluation of treatment in the immunocompromised host.

Ireland in the World Cup: trauma orthopaedic workloads

To determine if whether there were any changes in numbers of orthopaedic injuries at the emergency/ orthopaedic trauma department requiring treatment that could be related to televised home matches during World Cup 2002. Numbers of patients attending with musculoskeletal injuries directly attributable to world cup celebrations were collected during the four home matches. Attendances from midnight before the match until midday the day after the match were recorded. Control groups were matched from the previous month of May, and matched with the same day of the week for each of the four groups. Significantly more patients were admitted to the trauma service, referred to orthopaedic outpatients, and referred to the minor trauma clinic in the match versus control groups. 280 patients required onward referral during the match period compared with 233 during the control period. Televised Irish matches during the World Cup significantly increased the workload of the trauma orthopaedic service with musculoskeletal injuries. This should be taken into account when planning for such events in the future.

Computed tomography wire localisation-assisted operative retrieval of a migrated symphysis pubis plate from the ischiorectal fossa

We report an unusual case of migration of a metal plate from the symphysis pubis to the left ischiorectal fossa, and a technique of using pre-operative CT guided wire localisation of the plate as a successful method of assisting plate retrieval.

Effect of CD40 ligand on the course of murine histoplasmosis

CD40 ligand-CD40 ligation is important in the development of T-cell-mediated immune responses. The purpose of this study was to examine the role of CD40L in recovery from histoplasmosis using a murine model of intratracheally induced infection. B6C3F1 mice were infected intratracheally with Histoplasma capsulatum yeast and monitored for clearance of the organism from the lungs and spleen. CD40L treatment was begun on either day -2 or +2 post inoculation and continued until day 14 in CD4-depleted animals and from day -2 to day +4 in non-immunosuppressed animals. Amphotericin B treatment was begun four days following inoculation and given every other day for 10 days. CD40L reduced fungal burden by less than one log when started two days before infection but did not act synergistically with low-dosage amphotericin B (0.2 mg kg(-1) qod) in CD4 depleted mice. Low-dose amphotericin B, CD40L, and the combination of the two failed to lower the fungal burden in a second experiment using a more virulent isolate of the same strain of H. capsulatum in CD4-depleted mice. Furthermore, CD40L did not increase the concentrations of IFN-gamma, IL-12 or IL-10 in the lungs or spleens of infected animals. In summary, CD40L had minimal or no effect on the course of infection in this murine model of histoplasmosis.

Emergence of resistance to fluconazole as a cause of failure during treatment of histoplasmosis in patients with acquired immunodeficiency disease syndrome

In sequential clinical trials of treatment for histoplasmosis in patients with acquired immunodeficiency syndrome, therapy with fluconazole failed in a higher proportion of patients than did therapy with itraconazole. To determine the cause for failure with fluconazole, antifungal susceptibility testing that used modified National Committee on Clinical Laboratory Standards procedures was performed on all baseline and failure isolates. Failure occurred more frequently in patients with baseline isolates with fluconazole minimum inhibitory concentrations (MICs) > or =5 microg/mL versus lower MICs; 29% versus 3%, respectively. There was at least a 4-fold increase in fluconazole MIC in the isolates from 10 (59%) of 17 patients for whom paired pretreatment and failure or relapse isolates were available. Cross-resistance to itraconazole was not seen. In conclusion, fluconazole is less active than itraconazole for Histoplasma capsulatum and induces resistance during therapy, which accounted for treatment failure in some patients.

Clearance of fungal burden during treatment of disseminated histoplasmosis with liposomal amphotericin B versus itraconazole

Animal studies have shown that fungal burden correlates with survival during treatment with new antifungal therapies for histoplasmosis. The purpose of this report is to compare the clearance of fungal burden in patients with histoplasmosis treated with liposomal amphotericin B versus itraconazole. In two separate closed clinical trials that evaluated the efficacy of liposomal amphotericin B and itraconazole treatment of disseminated histoplasmosis in patients with AIDS, blood was cultured for fungus and blood and urine were tested for Histoplasma antigen. The clinical response rates were similar; 86% with liposomal amphotericin B (n = 51) versus 85% with itraconazole (n = 59). Of the patients with positive blood cultures at enrollment, after 2 weeks of therapy cultures were negative in over 85% of the liposomal amphotericin B group versus 53% of the itraconazole group (P = 0.0008). Furthermore, after 2 weeks, median antigen levels in serum fell by 1.6 U in the liposomal amphotericin B group versus 0.1 U in the itraconazole group (P = 0.02), and those in urine fell by 2.1 U in the liposomal amphotericin B group and 0.2 U in the itraconazole group (P = 0.0005). The more rapid clearance of fungemia supports the use of liposomal amphotericin B rather than itraconazole for initial treatment of moderately severe or severe histoplasmosis.

Cadaveric fibula, locking plate, and allogeneic bone matrix for anterior cervical fusions after cervical discectomy for radiculopathy or myelopathy

OBJECT

The authors have previously reported that the results of using cadaveric fibula and locking plate (CF/LP) fusion following anterior cervical discectomy (ACD) for cervical spondylotic radiculopathy and myelopathy are superior to those obtained using autologous iliac crest (AIC) grafts in the short term. The long-term results of using this construct are important in substantiating this improvement. The authors report on 246 consecutive patients (54% smokers) who underwent ACD with CF/LP fusion (175 with allogeneic bone matrix [ABM]) and compare them with 111 consecutive patients in whom AIC fusions (49% smokers) were performed by the same surgeons.

METHODS

The study is a retrospective nonrandomized analysis, and chi-square statistics were used. Bone densitometric studies of AIC grafts and CF grafts were performed. A paired t-test was used for statistical analysis of the results. Disease in the group of patients undergoing CF/LP fusion included soft-disc herniation with radiculopathy in 14, soft-disc hemiation with myelopathy in seven, cervical spondylotic radiculopathy in 144, cervical spondylotic myelopathy in 75, AIC graft collapse pseudarthrosis in five, and ACD with no fusion collapse/kyphosis in one. Operations consisted of single-level CF/LP fusion in 142 patients and multilevel CF/LP fusion in 104. Perioperative complications in the CF/LP group included three cases of transient hoarseness. There were no transfusions, infections, neurological injuries, or deaths. The mean hospital length of stay was 1.2 days (28% outpatient and 66% 23-hour stay). The mean follow-up period was 60 months (range 12-94 months). Ten patients were lost to follow up after 1 year. Long-term complications included one traumatic plate fracture and one symptomatic pseudarthrosis with plate fracture. At 1 year and beyond, in 245 (99.6%) of 246 patients radiographically documented fusion with no motion at the fused level on flexion-extension films was demonstrated. There was no kyphosis, no symptomatic screw plate backout, and no CF/LP graft collapse (100% in the ABM group). In the 111 consecutive patients with AIC fusions, however, there was a 17% graft-related complication rate. There were significantly fewer graft-related complications in the CF/LP group (p < 0.001). There was no difference in neurological outcome for any of the groups. In the groups undergoing single-level ACD there was a significantly greater chance of complete relief of neck pain CF/LP fusion compared with those undergoing AIC fusion (p < 0.02). There was a significantly greater chance of AIC collapse with the passage of time compared with CF graft (p < 0.02). Time until return to work was shorter for the CF/LP group by 5 to 6 weeks (p < 0.02). There was a higher rate of radiographically documented pseudarthrosis in the AIC group (p < 0.006). The mean bone densitometry for the CF/LP group was 0.7 g/cm2, significantly greater than that of the AIC group, which was 0.2 g/cm2 (paired t-test p < 0.001).

CONCLUSIONS

When fusion is necessary following ACD, the results of CF/LP fusion are significantly superior in the first 5 years after surgery compared with those for AIC fusions. It remains to be determined if demineralized ABM has a significant effect in enhancing fusion.

Chronic Infection and Reactivation in a Pulmonary Challenge Model of Histoplasmosis

Reactivation may be a mechanism for the development of histoplasmosis in AIDS. In this study, histoplasmosis was reactivated by the depletion of CD4 and CD8 lymphocytes in mice. CD4 and/or CD8 depletion beginning 1 month after intratracheal infection and continuing for 2 months caused reactivation with a 2.1 log/g increase in the lungs and a 1.5 log increase in the spleen of B6C3F1 mice. Because control animals showed persistent infection, a subsequent experiment sought to determine the long-term outcome in competent mice. Twelve of 32 immunocompetent mice died at weeks 26-52 of infection, and 4 survivors appeared to be clinically ill; all ill mice had high fungus burdens, whereas cultures were sterile in the healthy mice. Eight of the surviving healthy-appearing mice underwent autopsy 2 years after infection, and cultures were sterile. Thus, 16 of 32 immunocompetent mice exhibited progressive infection. CD4 and/or CD8 depletion exacerbated infection, but a chronic progressive and ultimately fatal infection occurred in half the immunocompetent mice.

Recovery of Cardiac Function after Standard Hypothermic Storage Versus Preservation with Peg-Hemoglobin

Preservation of the heart for transplantation after infusion of cardioplegia and extirpation of a cardiac allograft results in an ischemic insult to the myocardium. This ischemic insult may lead to a loss of function in the transplanted heart. Hypothermic perfusion preservation with an oxygen hemoglobin carrying solution may avert ischemic injury and lead to improved recovery of cardiac function. The purpose of this study was to compare cardiac function after 8 hours of continuous hypothermic perfusion with a unique polyethylene-glycol-hemoglobin (PEG-Hb) solution to hearts preserved by 4 hours of hypothermic ischemic storage. Freshly extirpated hearts served as functional controls. The hearts of 26 anesthetized and intubated New Zealand white rabbits were harvested after cold cardioplegic arrest. Group I (n = 12) hearts were perfused with a PEG-Hb solution at 20 degrees C and 30 mm Hg for 8 hours. PO2 was maintained > or = 500 mm Hg. Group II (n = 7) hearts were preserved by cold ischemic storage for 4 hours at 4 degrees C. Group III (n = 7) were tested immediately after harvest. Left ventricular (LV) function was measured in the nonworking state at 15 minutes, 1 hour, and 2 hours after transfer to a standard crystalloid Langendorff circuit. Measurement of LV developed pressure, peak + dP/dt and -dP/dt revealed a superior trend between Group I and Group II hearts in comparison with freshly extirpated hearts. Heart rate was similar among all groups throughout testing (p = ns). Coronary blood flow was not significantly different between groups. Continuous perfusion preservation of rabbit hearts for 8 hours with PEG-Hb solution at 30 mm Hg and 20 degrees C yielded LV function that was similar to 4 hours of ischemic hypothermic storage. Furthermore, return of cardiac function after 8 hours of perfusion preservation using this PEG-Hb solution may be superior to that obtained in freshly extirpated hearts. These data suggest that some recovery of myocardial function may occur during perfusion preservation with this PEG-Hb solution after the ischemic insult of cardioplegic arrest. Continuous perfusion preservation using this PEG-Hb solution deserves further investigation in large animal transplant models.

Comparison of a new triazole, posaconazole, with itraconazole and amphotericin B for treatment of histoplasmosis following pulmonary challenge in immunocompromised mice

A murine model of intratracheally induced histoplasmosis in immunocompromised B6C3F(1) mice was used to evaluate a new triazole antifungal agent, posaconazole. This compound was previously shown to be comparable to amphotericin B and superior to itraconazole for the treatment of histoplasmosis in immunocompetent mice. The current study used mice that were depleted of T lymphocytes by intraperitoneal injection of anti-CD4 and anti-CD8 monoclonal antibodies beginning 2 days before infection and continuing at 5-day intervals until completion of the study. Groups of B6C3F(1) mice that were depleted of CD4 and CD8 T cells were infected with an inoculum of 10(4) Histoplasma capsulatum yeasts. All mice receiving posaconazole at 1 or 0.1 mg/kg of body weight/day, amphotericin B at 2 mg/kg every other day (qod), or itraconazole at 75 mg/kg/day survived to day 29. Only 60% of mice receiving itraconazole at 10 mg/kg/day and none receiving amphotericin B at 0.2 mg/kg qod survived to that date. Fungal burdens were determined at day 14 of infection, 1 day after discontinuation of therapy. Quantitative colony counts and Histoplasma antigen levels in lung and spleen tissues declined following treatment with amphotericin B at 2 mg/kg qod, posaconazole at 5 and 1 mg/kg/day, and itraconazole at 75 mg/kg/day but not in mice treated with amphotericin B at 0.2 mg/kg qod or itraconazole at 10 mg/kg/day. Posaconazole at 0.1 mg/kg/day reduced fungal colony counts and antigen levels in spleens but not in lungs. This study shows posaconazole activity for the treatment of histoplasmosis in immunosuppressed animals.

Leg length discrepancy--an experimental study of compensatory changes in three dimensions using gait analysis

Patients with leg length discrepancy (LLD) develop compensatory mechanisms, which result in kinematic alterations in the lower limbs and pelvis. We investigated these compensatory mechanisms. Seven normal subjects underwent three-dimensional (3-D) gait analysis using a CODA MPX 30(R) analyser. The subjects were fitted with raises of varying heights to one lower limb and then analysed in static and dynamic modes. Pelvic obliquity was the most common mechanism used to compensate for small degrees of leg length discrepancy up to 2.2 cm, particularly in static standing. With larger degrees of discrepancy, the subjects developed flexion of the knee of the longer leg. Compensatory mechanisms during walking were more complex and included a combination of kinematic changes at the pelvis, knee and ankle. We developed mathematical models for the compensatory mechanisms at all the three levels. We conclude that 3-D gait analysis is a useful tool in the assessment of patients with functional and structural leg length discrepancies.

Comparison of the echinocandin caspofungin with amphotericin B for treatment of histoplasmosis following pulmonary challenge in a murine model

Twenty clinical isolates of Histoplasma capsulatum were tested for their in vitro susceptibilities to caspofungin in comparison to those to amphotericin B by following National Committee for Clinical Laboratory Standards guidelines for yeasts. The mean MICs were 16.6 microgram/ml (range, 8 to 32 microgram/ml) for caspofungin and 0.56 microgram/ml (range, 0.5 to 1.0 microgram/ml) for amphotericin B. Survival experiments used a 10(5) dose in a pulmonary challenge model with B6C3F(1) mice. All mice that received amphotericin B at 2 mg/kg of body weight every other day (q.o.d.), 30% of mice that received caspofungin at 8 mg/kg/day, and 20% of mice that received caspofungin at 4 mg/kg/day survived to day 15, while mice that received caspofungin at 2 mg/kg/day and all control mice that received the vehicle died by day 14. Amphotericin B at 2 mg/kg q.o.d. markedly reduced the fungal burden in the lungs and spleens, as measured by Histoplasma antigen detection techniques and quantitative cultures, for each comparison. Caspofungin at 10 mg/kg twice a day (b.i.d.) did not reduce the fungal burden, as measured by antigen detection techniques, but slightly reduced the levels of fungi in both the lungs and spleens, as determined by quantitative cultures. Caspofungin at 5 mg/kg b.i.d. did not affect fungal burden. Overall, caspofungin had only a slight effect on survival or fungal burden.

Factors associated with severe manifestations of histoplasmosis in AIDS

We report factors associated with severe manifestations of histoplasmosis (such as shock, respiratory failure, and death) in patients with AIDS during an outbreak. Severe disease was present in 28 of 155 patients (17.9%). The following factors were associated with severe disease: black race (odds ratio [OR], 2.8; 95% confidence interval [CI], 1.2-6.2); hemoglobin level <9.5 g/dL (OR, 2.7; 95% CI, 1.2-6.4), partial thromboplastin time >45 s (OR, 3.1; 95% CI, 1.1-9.3); alkaline phosphatase level >2.5 times normal (OR, 3.4; 95% CI, 1.3-8.7); aspartate aminotransferase level >2.5 times normal (OR, 4.2; 95% CI, 1.7-10.0); bilirubin level concentration >1.5 mg/dL (OR, 9.2; 95% CI, 2.5-34.3); creatinine concentration >2.1 mg/dL (OR, 8.3; 95% CI, 2.2-31.9); and albumin concentration <3.5 g/dL (OR, 4.6; 95% CI, 1.3-16.4). Zidovudine use was associated with decreased risk of severe disease (OR, 0.3; 95% CI, 0.1-0.7). Multivariate analysis showed that a creatinine value >2.1 mg/dL (OR, 9.5; 95% CI, 1.7-52) and an albumin value <3.5 g/dL (OR, 4.8; 95% CI, 1.0-22) were associated with an increased risk of severe disease, and zidovudine therapy remained associated with a decreased risk (OR, 0.2; 95% CI, 0.1-0.6). Findings associated with severe histoplasmosis should be recognized early and the cases managed aggressively.

Comparison of nikkomycin Z with amphotericin B and itraconazole for treatment of histoplasmosis in a murine model

Nikkomycin Z was tested both in vitro and in vivo for efficacy against Histoplasma capsulatum. Twenty clinical isolates were tested for susceptibility to nikkomycin Z in comparison to amphotericin B and itraconazole. The median MIC was 8 microg/ml with a range of 4 to 64 microg/ml for nikkomycin Z, 0.56 microg/ml with a range of 0.5 to 1.0 microg/ml for amphotericin B, and < or =0.019 microg/ml for itraconazole. Primary studies were carried out by using a clinical isolate of H. capsulatum for which the MIC of nikkomycin Z was greater than or equal to 64 microg/ml. In survival experiments, mice treated with amphotericin B at 2.0 mg/kg/dose every other day (QOD) itraconazole at 75 mg/kg/dose twice daily (BID), and nikkomycin Z at 100 mg/kg/dose BID survived to day 14, while 70% of mice receiving nikkomycin Z at 20 mg/kg/dose BID and none of the mice receiving nikkomycin Z at 5 mg/kg/dose BID survived to day 14. All vehicle control mice died by day 12. Fungal burden was assessed on survivors. Mice treated with nikkomycin Z at 20 and 100 mg/kg/dose BID had significantly higher CFUs per gram of organ weight in quantitative cultures and higher levels of Histoplasma antigen in lung and spleen homogenates than mice treated with amphotericin B at 2.0 mg/kg/dose QOD or itraconazole at 75 mg/kg/dose BID. Studies also were carried out with a clinical isolate for which the MIC of nikkomycin Z was 4 microg/ml. All mice treated with amphotericin B at 2.0 mg/kg/dose QOD; itraconazole at 75 mg/kg/dose BID; and nikkomycin Z at 100, 20, and 5 mg/kg/dose BID survived until the end of the study at day 17 postinfection, while 30% of the untreated vehicle control mice survived. Fungal burden assessed on survivors showed similar levels of Histoplasma antigen in lung and spleen homogenates of mice treated with amphotericin B at 2.0 mg/kg/dose QOD; itraconazole at 75 mg/kg/dose BID; and nikkomycin Z at 100, 20, and 5 mg/kg/dose BID. The three surviving vehicle control mice had significantly higher antigen levels in lung and spleen than other groups (P<0.05). The efficacy of nikkomycin Z at preventing mortality and reducing fungal burden correlates with in vitro susceptibility.

Does long-term itraconazole prophylaxis result in in vitro azole resistance in mucosal Candida albicans isolates from persons with advanced human immunodeficiency virus infection? The National Institute of Allergy and Infectious Diseases Mycoses study group

The effects of prolonged itraconazole exposure on the susceptibility of Candida albicans isolates to itraconazole and fluconazole have not been well characterized. A recent placebo-controlled study of long-term itraconazole antifungal prophylaxis in persons with advanced human immunodeficiency virus infection afforded the opportunity to address this question. Mucosal Candida sp. isolates were obtained from subjects who developed oropharyngeal or esophageal candidiasis, and in vitro susceptibilities of the last isolate obtained at removal from the study as a prophylaxis failure were compared in itraconazole and placebo recipients. More subjects in the placebo group (74 of 146 [51%]) than in the itraconazole group (51 of 149 [34%]) developed mucosal candidiasis (P = 0.004). A total of 112 isolates were recovered from 56 of the 74 (76%) subjects with mucosal candidiasis assigned to the placebo group, compared to 97 isolates from 45 of the 51 (88%) subjects in the itraconazole group. C. albicans accounted for 98% of isolates in the placebo group and 89% of isolates in the itraconazole group. The itraconazole MIC at which 50% of the isolates tested were inhibited (MIC(50)) for last-episode isolates from the itraconazole group was 0.125 microg/ml compared to 0.015 microg/ml for the placebo group subjects, P = 0.0001. The MIC(50) of fluconazole for the last isolates from the itraconazole group was 1.5 microg/ml compared to 0.5 microg/ml for the placebo subjects (P = 0.005). A lower proportion of isolates recovered from subjects on itraconazole therapy were classified as susceptible to itraconazole (63%) compared to isolates from the placebo group (96%) (P = 0.001). Similarly, a lower proportion of C. albicans isolates from subjects on itraconazole therapy were susceptible to fluconazole (78%) compared to isolates from the placebo group (96%) (P = 0.01). Also, the proportion of isolates that were not fully susceptible to itraconazole or fluconazole was greater in patients assigned to the itraconazole group than the placebo group (itraconazole susceptibility, 37 and 4%, respectively (P = 0.001); fluconazole susceptibility, 23 and 4%, respectively (P = 0.01). In conclusion, long-term itraconazole prophylaxis in patients with AIDS is associated with reduction in susceptibility to itraconazole and cross-resistance to fluconazole.

Use of a dual monoclonal solid phase and a polyclonal detector to create an immunoassay for the detection of human cardiac troponin I

OBJECTIVES

We report the development of a fully automated, random access, chemiluminescent immunoassay, for the detection of human cardiac Troponin I (cTnI) in serum and plasma for use on the ACS:180(R) System.

DESIGN AND METHODS

This assay format uses a combination of two monoclonal antibodies covalently coupled to paramagnetic (PMP) particles as a solid phase and an affinity purified polyclonal antibody, specific to the N-terminal domain of cTnI (peptide-3 region) labeled with a chemiluminescent compound as the detector antibody. The assay offers excellent low-end sensitivity and precision.

RESULTS

No interferences are observed from by blood components such as HAMA and drugs used in cardiac therapy. Patient samples tested on the ACS:180 cTnI assay showed good correlation with the Stratus cTnI assay (ACS: cTnI = 1. 02*Stratus + 0.05 g/L, r = 0.96, n = 1170).

CONCLUSION

Paired with the other ACS:180 cardiac assays, myoglobin and CKMBII, the ACS:180 system now offers an excellent panel of cardiac assay for use in rapid and accurate diagnosis of a myocardial event.