Preoperative electroencephalographic alpha-power changes with eyes opening are associated with postoperative attention impairment and inattention-related delirium severity

BACKGROUND

In the eyes-closed, awake condition, EEG oscillatory power in the alpha band (7-13 Hz) dominates human spectral activity. With eyes open, however, EEG alpha power substantially decreases. Less alpha attenuation with eyes opening has been associated with inattention; thus, we analysed whether reduced preoperative alpha attenuation with eyes opening is associated with postoperative inattention, a delirium-defining feature.

METHODS

Preoperative awake 32-channel EEG was recorded with eyes open and eyes closed in 71 non-neurological, noncardiac surgery patients aged ≥ 60 years. Inattention and other delirium features were assessed before surgery and twice daily after surgery until discharge. Eyes-opening EEG alpha-attenuation magnitude was analysed for associations with postoperative inattention, primarily, and with delirium severity, secondarily, using multivariate age- and Mini-Mental Status Examination (MMSE)-adjusted logistic and proportional-odds regression analyses.

RESULTS

Preoperative alpha attenuation with eyes opening was inversely associated with postoperative inattention (odds ratio [OR] 0.73, 95% confidence interval [CI]: 0.57, 0.94; P=0.038). Sensitivity analyses showed an inverse relationship between alpha-attenuation magnitude and inattention chronicity, defined as 'never', 'newly', or 'chronically' inattentive (OR 0.76, 95% CI: 0.62, 0.93; P=0.019). In addition, preoperative alpha-attenuation magnitude was inversely associated with postoperative delirium severity (OR 0.79, 95% CI: 0.65, 0.95; P=0.040), predominantly as a result of the inattention feature.

CONCLUSIONS

Preoperative awake, resting, EEG alpha attenuation with eyes opening might represent a neural biomarker for risk of postoperative attentional impairment. Further, eyes-opening alpha attenuation could provide insight into the neural mechanisms underlying postoperative inattention risk.

Same-teams versus different-teams for long distance lung procurement: A cost analysis

OBJECTIVE

In an era of broader lung sharing, different-team transplantation (DT, procuring team from nonrecipient center) may streamline procurement logistics; however, safety and cost implications of DT remain unclear. To understand whether DT represents a safe means to reduce lung transplant (LTx) costs, we compared posttransplant outcomes and lung procurement and index hospitalization costs among matched DT and same-team transplantation (ST, procuring team from recipient center) cohorts at a single, high-volume institution. We hypothesized that DT reduces costs without compromising outcomes after LTx.

METHODS

Patients who underwent DT between January 2016 to May 2020 were included. A cohort of patients who underwent ST was matched 1:3 (nearest neighbor) based on recipient age, disease group, lung allocation score, history of previous LTx, and bilateral versus single LTx. Posttransplant outcomes and costs were compared between groups.

RESULTS

In total, 23 DT and 69 matched ST recipients were included. Perioperative outcomes and posttransplant survival were similar between groups. Compared with ST, DT was associated with similar lung procurement and index hospitalization costs (DT vs ST, procurement: median $65,991 vs $58,847, P = .16; index hospitalization: median $294,346 vs $322,189, P = .7). On average, procurement costs increased $3263 less per 100 nautical miles for DT versus ST; DT offered cost-savings when travel distances exceeded approximately 363 nautical miles.

CONCLUSIONS

At our institution, DT and ST were associated with similar post-LTx outcomes; DT offered cost-savings with increasing procurement travel distance. These findings suggest that DT may mitigate logistical and financial burdens of lung procurement; however, further investigation in a multi-institutional cohort is warranted.

The impact of regional anesthesia on opioid demand in distal radius fracture surgery

PURPOSE

Regional anesthesia (RA) is commonly used in distal radius fracture surgery to reduce pain and opioid consumption. The purpose of this study was to evaluate the real-world impact of RA on inpatient and outpatient opioid consumption and demand in patients undergoing distal radius fracture surgery.

METHODS

All patients ages 18 and older undergoing distal radius fracture surgery between 7/2013 and 7/2018 at a single institution (n = 969) were identified. Inpatient opioid consumption and outpatient opioid prescribing in oxycodone 5-mg equivalents (OE's) up to 90-d post-operative were recorded for patients with and without RA. Adjusted models were used to evaluate the impact of RA on opioid outcomes.

RESULTS

Adjusted models demonstrated decreases in inpatient opioid consumption in patients with RA (10.7 estimated OE's without RA vs. 7.6 OE's with RA from 0 to 24 h post-op, 10.2 vs. 5.3 from 24 to 48 h post-op and 7.5 vs. 5.0 from 48 to 72 h post-op, p<.05). Estimated cumulative outpatient opioid demand was significantly higher in patients with RA (65.3 OE's without RA vs. 81.0 with RA from 1-month pre-op to 2-week post-discharge, 76.1 vs. 87.7 OE's to 6-weeks, and 80.8 vs. 93.5 OE's to 90-d, all p values for RA <.05) though rates of refill were significantly lower in patients with RA from 2-week to 6-week post-op compared to patients without RA.

CONCLUSIONS

Patients undergoing RA in distal radius fracture surgery had decreased inpatient opioid consumption but increased outpatient demand after adjustment for patient and operative characteristics.

LEVEL OF EVIDENCE

Level III, retrospective, therapeutic cohort study.

Regional anesthesia reduces inpatient and outpatient perioperative opioid demand in periarticular elbow surgery

HYPOTHESIS

Regional anesthesia (RA) can be used to manage perioperative pain in the treatment of periarticular elbow fracture fixation. However, the opioid-sparing benefit is not well-characterized. The hypothesis of this study was that RA had reduced inpatient opioid consumption and outpatient opioid demand in patients who had undergone periarticular elbow fracture surgery.

METHODS

This study retrospectively reviews inpatient opioid consumption and outpatient opioid demand in all patients aged ≥18 years at a single Level I trauma center undergoing fixation of periarticular elbow (distal humerus and proximal forearm) fracture surgery (n=418 patients). In addition to RA vs. no RA, additional patient and operative characteristics were recorded. Unadjusted and adjusted models were constructed to evaluate the impact of RA and other factors on inpatient opioid consumption and outpatient opioid demand.

RESULTS

Adjusted models demonstrated decreases in inpatient opioid consumption postoperation in patients with RA (13.7 estimated oxycodone 5-mg equivalents or OEs without RA vs. 10.4 OEs with RA from 0 to 24 hours postoperation, P = .003; 12.3 vs. 9.2 OEs from 24 to 48 hours postoperation, P = .045). Estimated cumulative outpatient opioid demand differed significantly in patients with RA (166.1 vs. 132.1 OEs to 6 weeks, P = .002; and 181 vs. 138.6 OEs to 90 days, P < .001).

DISCUSSION

In proximal forearm and distal humerus fracture surgery, RA was associated with decreased inpatient and outpatient opioid demand after adjusting for baseline patient and treatment characteristics. These results encourage utilization of perioperative RA to reduce opioid use.

Lung transplantation after ex vivo lung perfusion versus static cold storage: An institutional cost analysis

Ex vivo lung perfusion (EVLP) is a novel lung preservation strategy that facilitates the use of marginal allografts; however, it is more expensive than static cold storage (SCS). To understand how preservation method might affect postoperative costs, we compared outcomes and index hospitalization costs among matched EVLP and SCS preserved lung transplant (LTx) recipients at a single, high-volume institution. A total of 22 EVLP and 66 matched SCS LTx recipients were included; SCS grafts were further stratified as either standard-criteria (SCD) or extended-criteria donors (ECD). Median total preservation time was 857, 409, and 438 min for EVLP, SCD, and ECD lungs, respectively (p < .0001). EVLP patients had similar perioperative outcomes and posttransplant survival compared to SCS SCD and ECD recipients. Excluding device-specific costs, total direct variable costs were similar among EVLP, SCD, and ECD recipients (median $200,404, vs. $154,709 vs. $168,334, p =  .11). The median direct contribution margin was positive for EVLP recipients, and similar to that for SCD and ECD graft recipients (all p > .99). These findings demonstrate that the use of EVLP was profitable at an institutional level; however, further investigation is needed to better understand the financial implications of EVLP in facilitating donor pool expansion in an era of broader lung sharing.

Textbook surgical outcome in lung transplantation: Analysis of a US national registry

Textbook surgical outcome (TO) is a novel composite quality measure in lung transplantation (LTx). Compared to one-year survival metrics, TO may better differentiate center performance, and motivate improvements in care. To understand the feasibility of implementing this metric, we defined TO in LTx using US national data, and evaluated its ability to predict post-transplant outcomes and differentiate center performance. Adult patients who underwent isolated LTx between 2016-2019 were included. TO was defined as freedom from post-transplant length of stay >30 days, 90-day mortality, intubation or extracorporeal membrane oxygenation at 72 hours post-transplant, post-transplant ventilator support lasting ≥5 days, postoperative airway dehiscence, inpatient dialysis, pre-discharge acute rejection, and grade 3 primary graft dysfunction at 72 hours. Recipient and donor characteristics and post-transplant outcomes were compared between patients who achieved and failed TO. Of 8959 lung transplant recipients, 4664 (52.1%) achieved TO. Patient and graft survival were improved among patients who achieved TO (both log-rank p<0.0001). Among 62 centers, adjusted rates of TO ranged from 27.0% to 72.4% reflecting a wide variability in center-level performance. TO defined using national data may represent a novel composite metric to guide quality improvement in LTx across US transplant centers. Summary: In this study we defined textbook outcome (TO) for lung transplantation (LTx) using US national data. We found that achievement of TO was associated with improved post-transplant survival, and wide variability in center-level LTx performance. These findings suggest that TO could be readily implemented to compare quality of care among US LTx centers. This article is protected by copyright. All rights reserved.

Electroencephalogram-Based Complexity Measures as Predictors of Post-operative Neurocognitive Dysfunction

Physiologic signals such as the electroencephalogram (EEG) demonstrate irregular behaviors due to the interaction of multiple control processes operating over different time scales. The complexity of this behavior can be quantified using multi-scale entropy (MSE). High physiologic complexity denotes health, and a loss of complexity can predict adverse outcomes. Since postoperative delirium is particularly hard to predict, we investigated whether the complexity of preoperative and intraoperative frontal EEG signals could predict postoperative delirium and its endophenotype, inattention. To calculate MSE, the sample entropy of EEG recordings was computed at different time scales, then plotted against scale; complexity is the total area under the curve. MSE of frontal EEG recordings was computed in 50 patients ≥ age 60 before and during surgery. Average MSE was higher intra-operatively than pre-operatively (p = 0.0003). However, intraoperative EEG MSE was lower than preoperative MSE at smaller scales, but higher at larger scales (interaction p < 0.001), creating a crossover point where, by definition, preoperative, and intraoperative MSE curves met. Overall, EEG complexity was not associated with delirium or attention. In 42/50 patients with single crossover points, the scale at which the intraoperative and preoperative entropy curves crossed showed an inverse relationship with delirium-severity score change (Spearman ρ = -0.31, p = 0.054). Thus, average EEG complexity increases intra-operatively in older adults, but is scale dependent. The scale at which preoperative and intraoperative complexity is equal (i.e., the crossover point) may predict delirium. Future studies should assess whether the crossover point represents changes in neural control mechanisms that predispose patients to postoperative delirium.

Lung transplantation using allografts with more than 8 hours of ischemic time: A single-institution experience

BACKGROUND

Six hours was historically regarded as the limit of acceptable ischemic time for lung allografts. However, broader sharing of donor lungs often necessitates use of allografts with ischemic time >6 hours. We characterized the association between ischemic time ≥8 hours and outcomes after lung transplantation using a contemporary cohort from a high-volume institution.

METHODS

Patients who underwent primary isolated bilateral lung transplantation between 1/2016 and 5/2020 were included. Patients bridged to transplant with extracorporeal membrane oxygenation or mechanical ventilation, and ex-vivo perfusion cases were excluded. Recipients were stratified by total allograft ischemic time <8 hours (standard) vs ≥8 hours (long). Perioperative outcomes and post-transplant survival were compared between groups.

RESULTS

Of 358 patients, 95 (26.5%) received long ischemic time (≥8 hours) lungs. Long ischemic time recipients were more likely to be male and have donation after circulatory death donors than standard ischemic time recipients. On unadjusted analysis, long and standard ischemic time recipients had similar survival, and similar rates of grade 3 primary graft dysfunction at 72 hours, extracorporeal membrane oxygenation post-transplant, acute rejection within 30 days, reintubation, and post-transplant length of stay. After adjustment, long and standard ischemic time recipients had comparable risks of mortality or graft failure.

CONCLUSIONS

In a modern cohort, use of lung allografts with "long" ischemic time ≥8 hours were associated with acceptable perioperative outcomes and post-transplant survival. Further investigation is required to better understand how broader use impacts post-lung transplant outcomes and the implications for smarter sharing under an evolving national allocation policy.

Global parental leave in surgical careers: differences according to gender, geographical regions and surgical career stages

BACKGROUND

There is a lack of information regarding the provision of parental leave for surgical careers. This survey study aims to evaluate the experience of maternity/paternity leave and views on work-life balance globally.

METHODS

A 55-item online survey in 24 languages was distributed via social media as per CHERRIES guideline from February to March 2020. It explored parental leave entitlements, attitude towards leave taking, financial impact, time spent with children and compatibility of parenthood with surgical career.

RESULTS

Of the 1393 (male : female, 514 : 829) respondents from 65 countries, there were 479 medical students, 349 surgical trainees and 513 consultants. Consultants had less than the recommended duration of maternity leave (43.8 versus 29.1 per cent), no paid maternity (8.3 versus 3.2 per cent) or paternity leave (19.3 versus 11.0 per cent) compared with trainees. Females were less likely to have children than males (36.8 versus 45.6 per cent, P = 0.010) and were more often told surgery is incompatible with parenthood (80.2 versus 59.5 per cent, P < 0.001). Males spent less than 20 per cent of their salary on childcare and fewer than 30 hours/week with their children. More than half (59.2 per cent) of medical students did not believe a surgical career allowed work-life balance.

CONCLUSION

Surgeons across the globe had inadequate parental leave. Significant gender disparity was seen in multiple aspects.

The Impact of the 2017 Kidney Allocation Policy Change on Simultaneous Liver-Kidney Utilization and Outcomes

Historically in the United States, kidneys for simultaneous liver-kidney transplantation (SLKT) candidates were allocated with livers, prioritizing SLKT recipients over much of the kidney waiting list. A 2017 change in policy delineated renal function criteria for SLKT and implemented a safety net for kidney-after-liver transplantation. We compared the use and outcomes of SLKT and kidney-after-liver transplant with the 2017 policy. United Network for Organ Sharing Standard Transplant Analysis and Research files were used to identify adults who received liver transplantations (LT) from August 10, 2007 to August 10, 2012; from August 11, 2012 to August 10, 2017; and from August 11, 2017 to June 12, 2019. LT recipients with end-stage renal disease (ESRD) were defined by dialysis requirement or estimated glomerular filtration rate <25. We evaluated outcomes and center-level, regional, and national practice before and after the policy change. Nonparametric cumulative incidence of kidney-after-liver listing and transplant were modeled by era. A total of 6332 patients received SLKTs during the study period; fewer patients with glomerular filtration rate (GFR) ≥50 mL/min underwent SLKT over time (5.8%, 4.8%, 3.0%; P = 0.01 ). There was also less variability in GFR at transplant after policy implementation on center and regional levels. We then evaluated LT-alone (LTA) recipients with ESRD (n = 5408 from 2012-2017; n = 2321 after the policy). Listing for a kidney within a year of LT increased from 2.9% before the policy change to 8.8% after the policy change, and the rate of kidney transplantation within 1 year increased from 0.7% to 4% (P < 0.001). After the policy change, there was no difference in patient survival rates between SLKT and LTA among patients with ESRD. Implementation of the 2017 SLKT policy change resulted in reduced variability in SLKT recipient kidney function and increased access to deceased donor kidney transplantation for LTA recipients with kidney disease without negatively affecting outcomes.

A template for physical resilience research in older adults: Methods of the PRIME-KNEE study

BACKGROUND

Older adults with similar health conditions often experience widely divergent outcomes following health stressors. Variable recovery after a health stressor may be due in part to differences in biological mechanisms at the molecular, cellular, or system level, that are elicited in response to stressors. We describe the PRIME-KNEE study as an example of ongoing research to validate provocative clinical tests and biomarkers that predict resilience to specific health stressors.

METHODS

PRIME-KNEE is an ongoing, prospective cohort study that will enroll 250 adults ≥60 years undergoing total knee arthroplasty. Data are collected at baseline (pre-surgery), during surgery, daily for 7 days after surgery, and at 1, 2, 4, and 6 months post-surgery. Provocative tests include a cognition-motor dual-task walking test, cerebrovascular reactivity assessed by functional near-infrared spectroscopy, peripheral blood mononuclear cell reactivity ex vivo to lipopolysaccharide toxin and influenza vaccine, and heart rate variability during surgery. Cognitive, psychological, and physical performance batteries are collected at baseline to estimate prestressor reserve. Demographics, medications, comorbidities, and stressor characteristics are abstracted from the electronic medical record and via participant interview. Blood-based biomarkers are collected at baseline and postoperative day 1. Repeated measures after surgery include items from a delirium assessment tool and pain scales administered daily by telephone for 7 days and cognitive change index (participant and informant), lower extremity activities of daily living, pain scales, and step counts assessed by Garmin actigraphy at 1, 2, 4, and 6 months after surgery. Statistical models use these measures to characterize resilience phenotypes and evaluate prestressor clinical indicators associated with poststressor resilience.

CONCLUSION

If PRIME-KNEE validates feasible clinical tests and biomarkers that predict recovery trajectories in older surgical patients, these tools may inform surgical decision-making, guide pre-habilitation efforts, and elucidate mechanisms underlying resilience. This study design could motivate future geriatric research on resilience.

Complications and functional outcomes after ileo-anal pouch excision-a systematic review of 14 retrospective observational studies

PURPOSE

The ileo-anal pouch (IAP) has been the gold standard procedure for maintenance of bowel continuity after panproctocolectomy for ulcerative colitis, familial adenomatous polyposis or hereditary non-polyposis colorectal cancer. However, the IAP has an estimated failure rate of 13% at 10 years post-procedure (Tulchinsky et al., Ann Surg 238(2):229-34, 2003), which can result in pouch excision (P.E.). This systematic review aims to synthesise all the available studies reporting post-operative outcomes of P.E. and its impact on patient quality of life (QoL), when available, which have not previously been summarised.

METHODS

PubMed, Embase, Medline and the Cochrane library databases were searched with terms 'Pouch AND excision' OR 'Pouch AND removal' OR 'Pouch AND remove' OR 'IAP AND excision'. All studies reporting post-operative morbidity, mortality or functional outcomes in patients who had P.E. were included. Studies with < 5 patients, non-English studies and conference abstracts were excluded.

RESULTS

14 studies comprising 1601 patients were included. Overall complications varied from 18 to 63% with the most common being persistent perineal sinus (9-40%) or surgical site infection (wound-2 to 30%; intra-abdominal collection-3 to 24%). The mortality rate was between 0.58 and 1.4%. QoL is generally lower in P.E. patients compared to the normal population across various QoL measures and P.E. patients often had urinary and sexual dysfunction post-operatively.

CONCLUSIONS

There is a substantial incidence of complications after P.E.; however, there is no evidence describing QoL pre- and post-P.E. Further longitudinal research comparing QoL in patients undergoing P.E. and other treatment options such as indefinite diversion is required to definitively assess QoL post-procedure.

HSV-2 meningoencephalitis in an immunocompetent young man: what is the pathogenesis and what is the treatment?

Herpes simplex encephalitis is rarely caused by herpes simplex virus type 2 (HSV-2) after the neonatal period. The pathogenesis of HSV-2 encephalitis is not known and its treatment has not been discussed. We report a case of mild meningoencephalitis secondary to HSV-2 primary infection after sexual risk behaviour in a healthy young man. The diagnosis was established upon clinical, biological and electroencephalographic criteria. Aciclovir treatment led to rapid clinical improvement. This case highlights HSV-2 as a rare cause of meningoencephalitis, and questions the management of this rare manifestation of HSV-2 infection.

The association between postprandial urinary C-peptide creatinine ratio and the treatment response to liraglutide: a multi-centre observational study

AIMS

The response to glucagon-like peptide 1 receptor agonist treatment may be influenced by endogenous β-cell function. We investigated whether urinary C-peptide creatinine ratio assessed before or during liraglutide treatment was associated with treatment response.

METHODS

A single, outpatient urine sample for urinary C-peptide creatinine ratio was collected 2 h after the largest meal of the day among two separate groups: (1) subjects initiating liraglutide (0.6 → 1.2 mg daily) or (2) subjects already treated with liraglutide for 20-32 weeks. The associations between pretreatment and on-treatment urinary C-peptide creatinine ratio and HbA1c change at 32 weeks were assessed using univariate and multivariate analyses (the ratio was logarithm transformed for multivariate analyses). Changes in HbA1c according to pretreatment urinary C-peptide creatinine ratio quartiles are shown.

RESULTS

One hundred and sixteen subjects (70 pretreatment, 46 on treatment) with Type 2 diabetes from 10 diabetes centres were studied. In univariate analyses, neither pretreatment nor on-treatment urinary C-peptide creatinine ratio correlated with HbA1c change (Spearman rank correlation coefficient, r = -0.17, P = 0.17 and r = -0.20, P = 0.19, respectively). In multi-linear regression analyses, entering baseline HbA1c and log urinary C-peptide creatinine ratio, pretreatment and on-treatment log urinary C-peptide creatinine ratio became significantly associated with HbA1c change (P = 0.048 and P = 0.040, respectively). Mean (sd) HbA1c changes from baseline in quartiles 1 to 4 of pretreatment urinary C-peptide creatinine ratio were -3 ± 17 mmol/mol (-0.3 ± 1.6%) (P = 0.52), -12 ± 15 mmol/mol (-1.1 ± 1.4%) (P = 0.003), -11 ± 13 mmol/mol (-1.0 ± 1.2%) (P = 0.002) and -12±17 mmol/mol (-1.1±1.6%) (P=0.016), respectively.

CONCLUSIONS

Postprandial urinary C-peptide creatinine ratios before and during liraglutide treatment were weakly associated with the glycaemic response to treatment. Low pretreatment urinary C-peptide creatinine ratio may be more useful than higher values by predicting poorer glycaemic response.

Visual motion perception predicts driving hazard perception ability

PURPOSE

To examine the basis of previous findings of an association between indices of driving safety and visual motion sensitivity and to examine whether this association could be explained by low-level changes in visual function.

METHODS

A total of 36 visually normal participants (aged 19-80 years) completed a battery of standard vision tests including visual acuity, contrast sensitivity and automated visual fields and two tests of motion perception including sensitivity for movement of a drifting Gabor stimulus and sensitivity for displacement in a random dot kinematogram (Dmin ). Participants also completed a hazard perception test (HPT), which measured participants' response times to hazards embedded in video recordings of real-world driving, which has been shown to be linked to crash risk.

RESULTS

Dmin for the random dot stimulus ranged from -0.88 to -0.12 log minutes of arc, and the minimum drift rate for the Gabor stimulus ranged from 0.01 to 0.35 cycles per second. Both measures of motion sensitivity significantly predicted response times on the HPT. In addition, while the relationship involving the HPT and motion sensitivity for the random dot kinematogram was partially explained by the other visual function measures, the relationship with sensitivity for detection of the drifting Gabor stimulus remained significant even after controlling for these variables.

CONCLUSION

These findings suggest that motion perception plays an important role in the visual perception of driving-relevant hazards independent of other areas of visual function and should be further explored as a predictive test of driving safety. Future research should explore the causes of reduced motion perception to develop better interventions to improve road safety.

Using acupuncture to treat depression: a feasibility study

OBJECTIVES

To establish the feasibility of conducting a randomised controlled trial to evaluate the efficacy of acupuncture in the treatment of mild-to-moderate depression. Control group intervention, blinding of treatment, outcome measures and the acceptability of such a trial amongst participants were key factors to be addressed. The findings from this study will be used to determine the design of a phase III randomised controlled trial.

DESIGN

Nineteen participants were recruited through general practices in London, UK. Participants were randomly assigned on a 2:1 basis to either 12 sessions of verum acupuncture or 12 sessions of sham acupuncture (control). Sham acupuncture involved actual needling but at sites considered to be unrelated to depression.

MAIN OUTCOME MEASURES

The Beck's Depression Inventory (BDI) and the RAND 36 Item Health Survey 1.0 (RAND) were completed at baseline and at the end of treatment or at treatment dropout. All participants also attended a brief qualitative interview at the end of the study.

RESULTS

Treatment dropout was low and there were high levels of patient enthusiasm for a study of acupuncture. Referrals from General Practitioners (GPs) were lower than expected. The sham control method successfully maintained participant blinding to treatment and enabled the specific (or active) component of an acupuncture intervention to be isolated and its efficacy assessed. The outcome measures were sensitive enough to record changes in depressive symptoms and quality of life and are appropriate for use in a larger trial.

CONCLUSIONS

This feasibility study has provided important information that can be used to guide the design and methodology of a full-randomised controlled trial.

The NH2-terminal propeptide of type I procollagen acts intracellularly to modulate cell function

The function of the NH(2)-terminal propeptide of type I procollagen (N-propeptide) is poorly understood. We now show that a recombinant trimeric N-propeptide interacts with transforming growth factor-beta1 and BMP2 and exhibits functional effects in stably transfected cells. The synthesis of N-propeptide by COS-7 cells results in an increase in phosphorylation of Akt and Smad3 and is associated with a marked reduction in type I procollagen synthesis and impairment in adhesion. In C2C12 cells, N-propeptide inhibits the osteoblastic differentiation induced by BMP2. Our data suggest that these effects are mediated by the interaction of N-propeptide with an intracellular receptor in the secretory pathway, because they are not observed when recombinant N-propeptide is added to the culture medium of either COS-7 or C2C12 cells. Both the binding of N-propeptide to cytokines and its functional properties are entirely dependent on the exon 2-encoded globular domain, and a mutation that substitutes a serine for a highly conserved cysteine in exon 2 abolishes its function. Our findings suggest that N-propeptide performs an important feedback regulatory function and provides a rationale for the prominence of a homotrimeric form of type I procollagen (alpha1 trimer) during vertebrate development.

Practical management strategies for diaper dermatitis

Common diaper dermatitis is an irritant contact diaper dermatitis (IDD) created by the combined influence of moisture, warmth, urine, feces, friction, and secondary infection. It is difficult to completely eradicate these predisposing factors in a diapered child. Thus, IDD presents an ongoing therapeutic challenge for parents, family physicians, pediatricians, and dermatologists. This article will focus on practical management strategies for IDD.

Characterization of nelfinavir binding to plasma proteins and the lack of drug displacement interactions

OBJECTIVES

To determine the characteristics of the binding of nelfinavir and active M8 to alpha1-acid glycoprotein (AAG) and human serum albumin (HSA), and to examine the displacement effects of drugs binding extensively to AAG (ritonavir and saquinavir) or to HSA (salicylic acid and valproic acid).

METHODS

Free drugs were separated by equilibrium dialysis after incubation with human plasma or purified plasma proteins and after co-incubation with potential displacers. Association constants were estimated from double-reciprocal plots of the data.

RESULTS

Nelfinavir and M8 free fractions [fractions of unbound drug (fus)] were 0.42+/-0.08% (mean+/-standard deviation) and 0.64+/-0.07%, respectively. For the two analytes, respectively, association constants were 7.25 x 10(7)/m and 3.33 x 10(7)/m for AAG and 1.11 x 10(6)/m and 7.92 x 10(5)/m for HSA. Nelfinavir fu in an AAG solution was significantly (P < 0.01) increased by the addition of ritonavir or saquinavir, whereas it was unaltered by addition of these drugs to whole plasma. Similarly, fu in an HSA solution was significantly increased (P < 0.01) by the addition of salicylic acid or valproic acid, whereas there was no difference in the free fraction in plasma.

CONCLUSIONS

The affinity of nelfinavir for human plasma proteins was higher than that of M8, and both nelfinavir and M8 showed higher affinity to AAG than to HSA. The free fraction of nelfinavir was not affected by drugs that bind extensively to AAG or albumin when these drugs were added to whole plasma in combination, suggesting a compensatory effect of alternate binding proteins.

Meal-dependent regulation of circulating glycated insulin in type 2 diabetic subjects

There is mounting evidence that elevated circulating concentrations of glycated insulin play a role in insulin resistance in type 2 diabetes. This study evaluated the secretion of glycated insulin in response to enteral stimulation in type 2 diabetic subjects. Following a mixed meal (450 kcal; 44 % carbohydrate; 40 % fat; 16 % protein), glycated insulin rose 10-fold to peak (60 min) at 104.5 +/- 25.0 pmol/l (p < 0.001), representing 22 % total circulating insulin. The response paralleled early rises in insulin and C-peptide, which peaked at 90 min and were more protracted. Maximum glucose concentrations were observed at 50 min. These data indicate that type 2 diabetic subjects exhibit a rapid meal-induced release of glycated insulin from readily releasable pancreatic beta-cell stores, which might contribute to impaired glucose homeostasis following enteral nutrition.

The effect of manipulation of basal pulsatile insulin on insulin action in Type 2 diabetes

AIM

Disordered insulin pulsatility is associated with insulin resistant states including Type 2 diabetes. However, whether abnormal basal insulin pulses play a role in the pathogenesis of insulin resistance or are simply an associated feature remains undetermined. We investigated this relationship further by studying the effect of overnight (10 h) pulsatile insulin infusion on subsequent insulin sensitivity.

METHODS

We studied 17 Type 2 diabetic patients who underwent one of two protocols. In protocol A (10 patients) on two separate nights we infused insulin 0.1 mU/kg/min either in a constant infusion or in pulses every 13 min. Octreotide (0.43 microg/kg/h) was given to suppress endogenous insulin secretion and physiological replacement of glucagon (30 ng/kg/h) administered. Insulin sensitivity was measured using a hyperinsulinaemic euglycaemic clamp (2 mU/kg/min) next morning. In protocol B (seven patients), we employed the same experimental procedure but used a basal insulin infusion rate of 0.09 mU/kg/min in 7-min or 13-min pulses.

RESULTS

Appropriate pulse patterns were confirmed in each protocol. In protocol A, after overnight infusions, glucose infusion rates required to maintain euglycaemia at steady state hyperinsulinaemia were similar (33.9 +/- 5.2 vs. 31.2 +/- 4.1 micromol/kg/min; P = NS). In protocol B, after overnight infusions the glucose infusion rates required during hyperinsulinaemia were significantly lower during 7-min pulses (39.9 +/- 5.7 vs. 44.7 +/- 5.6 micromol/kg/min; P < 0.05).

CONCLUSION

There was no demonstrable priming effect derived from overnight pulsatile insulin compared with constant insulin infusion on subsequent insulin sensitivity in Type 2 diabetic subjects. The failure of 7-min pulses to exhibit an advantageous effect over 13-min pulses raises questions about the natural frequency of basal insulin pulses and their biological effect.

Integrating Western medicine and Traditional Chinese medicine in GP surgeries and the community: a review of the two pilot schemes

The popularity of complementary medicine has been relentless over the past decade. Among the most popular are Traditional Chinese Medicine (TCM) which has a long and unbroken history. This article reports on two integrated health care pilot schemes where TCM and Western medicine are merged, to varying degrees, for the benefits of patients. One of the schemes focuses on general medicine whilst the other focuses on mental health. The authors conclude that the integrated schemes have many advantages and, on the whole, are beneficial for patients. The issues involved and learning points are discussed.

Infectious mononucleosis in an outpatient population: diagnostic utility of 2 automated hematology analyzers and the sensitivity and specificity of Hoagland's criteria in heterophile-positive patients

OBJECTIVES

To determine the sensitivity and specificity of 2 modern hematology analyzers in flagging heterophile-positive patients; to determine if heterophile-positive, instrument-flagged specimens contain a larger number or a different spectrum of atypical lymphocytes; to document the overall sensitivity and specificity of Hoagland's morphologic criteria in identifying heterophile-positive patients in an outpatient population with a clinical diagnosis of mononucleosis; and to examine whether individual morphologic features might aid in the diagnosis of suspected infectious mononucleosis.

DESIGN

A prospective study of patients referred with a clinical diagnosis of infectious mononucleosis who subsequently tested positive for the heterophile antibody. The control group consisted of a similar population of patients who tested negative for the heterophile antibody.

INTERVENTION

Hematology profiles of peripheral blood samples were determined with Coulter STKS and Sysmex NE-8000 analyzers. A corresponding Wright-Giemsa-stained blood smear was subsequently examined by a single skilled technologist, who performed a 200-cell white blood cell differential and a 200-cell lymphocyte differential. A specific morphologic search was made for the presence of smudge cells or lymphocytes with cloverleaf nuclei.

RESULTS

Using a combination of all flagging criteria, the 2 analyzers identified 156 (86.2%) of 181 heterophile-positive patients as meriting further review. The sensitivity and specificity values of the Coulter analyzer in predicting positive heterophile status for the blast flag were 41% and 97.1%, respectively; for the variant lymphocyte flags, 72.4% and 79.1%, respectively; and for both flags, 40% and 98.1%, respectively. For the Sysmex analyzer, the sensitivity and specificity values in predicting positive heterophile status for the blast flag were 43.4% and 88.6%, respectively; for the variant lymphocyte flag, 15.8% and 90.8%, respectively; and for both flags, 10.5% and 96%, respectively. Considering the classic criteria developed by Hoagland, a lymphocytosis of at least 50% was present in 120 (66.3%) heterophile-positive patients, while an atypical lymphocytosis of at least 10% of the total WBC count was noted in 135 patients (74.6%). The sensitivity and specificity values of a lymphocytosis > or =50% for diagnosing heterophile-positive status were 66.3% and 84.5%, respectively, while the sensitivity and specificity of an atypical lymphocytosis > or =10% were 74.6% and 92.3%, respectively. The presence of smudge cells or cloverleaf lymphocyte nuclei was verified as having high specificity but low sensitivity for suggesting a diagnosis of infectious mononucleosis.

CONCLUSION

Although a number of patients did not meet Hoagland's criteria for the diagnosis of infectious mononucleosis, the flagging systems of modern hematology analyzers successfully identified most cases as requiring further review.

Effect of food on the bioavailability of SDZ DJN 608, an oral hypoglycemic agent, from a tablet and a liquid-filled capsule in the dog

PURPOSE

The effect on food on the bioavailability of SDZ DJN 608, a D-phenylalanine derivative, was investigated in three mature, male beagle dogs.

METHODS

Each dog received, under fasting and postprandial conditions, a 30 mg oral dose as a tablet (T) and a liquid-filled capsule (LC). Additionally, a 5 mg intravenous dose was given in the fasting state. Doses in the same dog were separated by 1-week washout periods. Serial plasma samples were collected for 24 h postdose and analyzed for SDZ DJN 608 using HPLC. Model-independent pharmacokinetic parameters were compared between treatments by 3-way ANOVA: In vitro dissolution profiles of T and LC were generated using the USP paddle method. In addition, the transport of SDZ DJN 608 through a Caco-2 cell monolayer was examined at concentrations of 0.1 and 1 mM, in the absence and presence of an aromatic amino acid, L-alpha-methyldopa, the transport of which is mediated by the large neutral amino acid (LNAA) carrier.

RESULTS

In the dog, SDZ DJN 608 was rapidly absorbed. The peak plasma concentration (Cmax) averaged higher, and the peak time (tmax) shorter, after LC than T, though the differences were not statistically significant. This finding is consistent with in vitro dissolution data showing that, at both pH 1.2 and pH 6.8, the dissolution rate of LC was faster than that of T. No significant difference in the area under curve (AUC) was observed between LC and T, the absolute bioavailability of both being complete in the fasting state. Whereas the presence of food showed little effect on the tmax and Cmax of either dosage form, it significantly reduced the AUC, the effect (ca -20%) being not different between LC and T. In the Caco-2 model, the mucosal-to-serosal permeability of SDZ DJN 608 was independent of concentration and unaffected by L-alpha-methyldopa, suggesting passive diffusion of the former.

CONCLUSIONS

Food had little effect on the absorption rate but significantly reduced the bioavailability of SDZ DJN 608 regardless of the dosage form. This effect is unlikely to be caused by inhibition of the transepithelial transport of SDZ DJN 608 by amino acids in the diet.

beta-Lactamase of Lysobacter enzymogenes: cloning, characterization and expression of the gene and comparison of the enzyme to other lactamases

The gene for the periplasmic beta-lactamase of Lysobacter enzymogenes was isolated as part of a 1017 bp EcoRI fragment and the nucleotide sequence of the gene was determined. It has a G+C content of 71.5% and encodes a 27 amino acid signal sequence and the mature beta-lactamase of 276 amino acids which has a mass of 29,146 Da. The enzyme appears to be unique to L. enzymogenes but its amino acid sequence shows a high degree of homology with the amino acid sequences of the lactamase from Citrobacter diversus and other Class A beta-lactamases. The beta-lactamase gene of L. enzymogenes was expressed in Escherichia coli using pUC118 as the vector. The production of active beta-lactamase was highest after the active growth phase of the expression host and reached levels which were about three times higher than those obtained with L. enzymogenes.

Nucleotide sequence and characterization of the gene for secreted alkaline phosphatase from Lysobacter enzymogenes

Lysobacter enzymogenes produces an alkaline phosphatase which is secreted into the medium. The gene for the enzyme (phoA) was isolated from a recombinant lambda library. It was identified within a 4.4-kb EcoRI-BamH1 fragment, and its sequence was determined by the chain termination method. The structural gene consists of an open reading frame which encodes a 539-amino-acid protein with a 29-residue signal sequence, followed by a 119-residue propeptide, the 281-residue mature phosphatase, and a 110-residue carboxy-terminal domain. The roles of the propeptide and the carboxy-terminal peptide remain to be determined. A molecular weight of 30,000 was determined for the mature enzyme from sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The amino acid sequence was compared with sequences available in the current protein data base, and a region of the sequence was found to show considerable homology with sequences in mammalian type 5 iron-containing purple acid phosphatases.

Aminoglycoside antibiotics preferentially increase permeability in phosphoinositide-containing membranes: a study with carboxyfluorescein in liposomes

The rate of release from multilamellar liposomes of the fluorescent probe carboxyfluorescein was determined as a measure of membrane permeability. Liposomes of phosphatidylcholine and different anionic phospholipids were incubated with low (1 microM) and high (3 mM) concentrations of calcium in the absence or presence of aminoglycoside antibiotics. The leakage of carboxyfluorescein into the medium was not caused by liposomal fusion as no vesicle fusion was observed in experiments with terbium and dipicolinic acid-loaded liposomes. The basal rate of carboxyfluorescein release (in the absence or presence of 1 microM calcium) from all types of liposomes ranged from 0.1 to 0.3% of trapped carboxyfluorescein per hour. The presence of 3 mM calcium caused the greatest increase in the rate of carboxyfluorescein release (about 9-fold) in liposomes containing phosphatidylinositol 4,5-bisphosphate (PIP2) whereas liposomes containing the other anionic phospholipids (phosphatidylserine, phosphatidylinositol and phosphatidylinositol 4-phosphate) showed an approximate 5-fold increase. In the presence of 1 microM calcium, the aminoglycosides neomycin and gentamicin also increased the rate of carboxyfluorescein release, with PIP2-containing liposomes showing a 3-5-times greater response than the other liposomes, releasing up to 4.6% of trapped carboxyfluorescein per hour. This drug-induced release was dose-dependent and antagonized by calcium. In the presence of 3 mM calcium, 0.1 mM gentamicin or neomycin were ineffective while the drug at 1 mM affected carboxyfluorescein release from PIP2-liposomes only. The aminoglycoside antibiotics, neomycin, gentamicin, tobramycin, kanamycin, amikacin, netilmicin, as well as neamine and spectinomycin (all at 0.1 mM) showed a graded effect on the rate of carboxyfluorescein release from PIP2-containing vesicles in the presence of 0.1 mM calcium. The magnitude of the effect correlated well with the ototoxicity of the drugs previously determined directly in cochlear perfusions in the guinea pig. The study demonstrates that aminoglycoside antibiotics are capable of altering membrane permeabilities and that this effect is most pronounced if PIP2 is present in the bilayers. The excellent correlation between this membrane action and the in-situ toxicity of the drugs further establishes the specific role of PIP2 in the molecular mechanism of aminoglycoside-induced hearing loss. Moreover, it confirms the usefulness of such physicochemical models for the screening and prediction of aminoglycoside toxicity.

Membrane effects of aminoglycoside antibiotics measured in liposomes containing the fluorescent probe, 1-anilino-8-naphthalene sulfonate

The mechanism of membrane disturbance by aminoglycoside antibiotics was investigated in liposomes containing the fluorescent probe, 1-anilino-8-naphthalene sulfonate (ANS). Liposomes of PC and different anionic phospholipids (1:1 to 15:1 molar ratios) were challenged with aminoglycosides in the presence of low (1 microM) and high (3 mM) concentrations of calcium. Liposomes containing PIP2 showed the greatest drug-induced changes in ANS fluorescence in the presence of high and low concentrations of calcium and at all PC:PIP2 molar ratios tested. Liposomes containing other anionic phospholipids (PS, PI and PIP) were not reactive toward aminoglycosides in the presence of 3 mM calcium or when the ratio of PC to anionic lipid was increased to 10:1. The aminoglycoside-induced changes of ANS fluorescence were not due to any changes in the emission spectrum of ANS, nor to changes in quantum yield, nor to a change in the binding affinity of ANS. It is concluded that a specific aminoglycoside-PIP2 interaction results in phase separation of PC and PIP2 and thus increases the number of available ANS binding sites in PC:PIP2 liposomes.

Membrane perturbation by aminoglycosides as a simple screen of their toxicity

A simple test to assess the toxicity of aminoglycosides was designed based on the interaction of these drugs with phosphatidylinositol bisphosphate. The fluorescent probe 1-anilino-8-naphthalene sulfonate was incorporated into liposomes composed of L-alpha-phosphatidylcholine and phosphatidylinositol bisphosphate (4:1 molar ratio), and changes in fluorescence induced by the aminoglycosides were measured. The magnitude of these changes correlated well with the intrinsic ototoxicity of the drugs previously established in cochlear perfusions: neomycin greater than gentamicin approximately equal to tobramycin greater than amikacin approximately equal to kanamycin approximately equal to netilmicin greater than neamine approximately equal to spectinomycin. Correlations were not accurate when other phospholipids were substituted for phosphatidylinositol bisphosphate. An alternative in vitro test, measurement of the zeta potential of liposomes, ranked the drugs according to their electrostatic charge but not their toxicity. These results suggest that: a simple screen for aminoglycoside toxicity can be established and perturbation of membranes containing phosphatidylinositol bisphosphate is a key step in aminoglycoside ototoxicity.