Epidemiology, clinical outcomes and risk factors of third-generation cephalosporin-resistant Escherichia coli hospitalized infections in remote Australia-a case-control study

Background

Incidence of third-generation cephalosporin-resistant (3GCR) Escherichia coli infections has increased in remote Australia from 2012 to 2018.

Objectives

To describe the epidemiology of 3GCR E. coli in Central Australia.

Methods

A case-control study was conducted in the primary Central Australian hospital. Patient characteristics, antibiotic usage and clinical outcomes were compared between adult hospitalizations with 3GCR and susceptible E. coli isolates in 2018-19. Poisson regression was used to compare the incidence of 3GCR hospitalizations between Indigenous and non-Indigenous individuals. Patient characteristics and antibiotic usage were tested for associations with 3GCR isolates using univariate analysis.

Results

A total of 889 E. coli isolates were identified, of which 187 (21%) were 3GCR. The incidence of 3GCR E. coli infection was 2.15 per 1000 person-years, with an incidence rate ratio of 6.8 (95% CI 4.6-10.1) between Indigenous and non-Indigenous individuals. When compared with the control group, 3GCR E. coli infections were associated with a higher Charlson comorbidity index (CCI ≥3 in 30.7% versus 15.0%, P < 0.001) and were more commonly healthcare associated (52.4% versus 26.7%, P < 0.001). A higher 1 year mortality was observed in the 3GCR group after adjustment for comorbidity (OR = 4.43, P = 0.002), but not at 30 days (2.4% versus 0.0%, P = 0.2). The 3GCR group used more antibiotics in the past 3 months (OR = 5.75, P < 0.001) and 12 months (OR = 3.65, P < 0.001).

Conclusions

3GCR E. coli infections in remote Australia disproportionally affect Indigenous peoples and are associated with a high burden of comorbidities and antibiotic use. Strategies to enhance antimicrobial stewardship should be considered in this remote setting.

Validating a novel three-times-weekly post-hemodialysis ceftriaxone regimen in infected Indigenous Australian patients-a population pharmacokinetic study

OBJECTIVES

To describe the total and unbound population pharmacokinetics of a 2 g three-times-weekly post-dialysis ceftriaxone regimen in Indigenous Australian patients requiring hemodialysis.

METHODS

A pharmacokinetic study was carried out in the dialysis unit of a remote Australian hospital. Adult Indigenous patients on intermittent hemodialysis (using a high-flux dialyzer) and treated with a 2 g three-times-weekly ceftriaxone regimen were recruited. Plasma samples were serially collected over two dosing intervals and assayed using validated methodology. Population pharmacokinetic analysis and Monte Carlo simulations were performed using Pmetrics in R. The probability of pharmacokinetic/pharmacodynamic target attainment (unbound trough concentrations ≥1 mg/L) and toxicity [trough concentrations (total)  ≥100 mg/L] were simulated for various dosing strategies.

RESULTS

Total and unbound concentrations were measured in 122 plasma samples collected from 16 patients (13 female) with median age 57 years. A two-compartment model including protein-binding adequately described the data, with serum bilirubin concentrations associated (inversely) with ceftriaxone clearance. The 2 g three-times-weekly regimen achieved 98% probability to maintain unbound ceftriaxone concentrations ≥1 mg/L for a serum bilirubin of 5 µmol/L. Incremental accumulation of ceftriaxone was observed in those with bilirubin concentrations >5 µmol/L. Three-times-weekly regimens were less probable to achieve toxic exposures compared with once-daily regimens. Ceftriaxone clearance was increased by >10-fold during dialysis.

CONCLUSIONS

A novel 2 g three-times-weekly post-dialysis ceftriaxone regimen can be recommended for a bacterial infection with an MIC ≤1 mg/L. A 1 g three-times-weekly post-dialysis regimen is recommended for those with serum bilirubin ≥10 µmol/L. Administration of ceftriaxone during dialysis is not recommended.

Prediction accuracy of commonly used pneumonia severity scores in Aboriginal patients with severe community-acquired pneumonia: a retrospective study

BACKGROUND

Severe community-acquired pneumonia (SCAP) is highly prevalent in the Aboriginal population. Few pneumonia severity scores are validated in this population.

AIMS

To assess the prediction accuracy of pneumonia severity scores in Aboriginal patients with SCAP and to identify risk factors for poor prognosis.

METHODS

Retrospective cohort study examining Aboriginal patients admitted to the intensive care unit with confirmed SCAP between January 2011 and December 2014. Severity scores were calculated for SMARTCOP (systolic blood pressure, multi-lobar, albumin, respiratory rate, tachycardia, confusion, oxygenation and arterial pH), SMARTACOP (systolic blood pressure, multi-lobar, albumin, respiratory rate, tachycardia, Aboriginal status, confusion, oxygenation and arterial pH), CURB-65 (confusion, urea, respiratory rate, blood pressure and age ≥65 years), pneumonia severity index, Infectious Diseases Society of America and American Thoracic Society SCAP, and Acute Physiology and Chronic Health Evaluation (APACHE) II/III using medical records. Prediction accuracy of 30-day mortality and requirement for intensive respiratory and/or vasoactive support (IRVS) were assessed using logistic regression and the area under the receiver operating characteristic curve (AUROC). Multivariate analysis was used to test associations between poor prognosis and demographic/clinical variables.

RESULTS

A total of 203 cases (49% women) was identified. Thirty-day mortality was 6.4% (n = 13), and 53% (n = 107) required IRVS. None of the tested pneumonia severity scores accurately predicted mortality. SMARTCOP and SMARTACOP predicted IRVS requirement with the highest diagnostic accuracy, but only achieved acceptable discrimination (P <0.001 and <0.001; AUROC = 0.74 and 0.75 respectively). APACHE II/III predicted both mortality (P = 0.003 and 0.001; AUROC = 0.74 and 0.73 respectively) and IRVS requirement (P <0.001 and <0.001; AUROC = 0.72 and 0.73 respectively). Multivariate analysis associated mortality with male gender, cirrhosis, immunosuppression and acidaemia, and IRVS requirement with multi-lobar pneumonia, hypotension and tachypnoea. Multivariate analysis for mortality and IRVS requirement achieved an AUROC of 0.93 and 0.87 respectively.

CONCLUSION

None of the pneumonia severity scores accurately predicted mortality. We recommend SMARTACOP to predict IRVS requirement in Aboriginal patients with SCAP. Given Aboriginal patients are over-represented in Australian intensive care units, a new score is warranted for this understudied population.

Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO's and Advanced Virgo's Third Observing Run

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2  M_{⊙} and 1.0  M_{⊙} in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14  yr^{-1}. This implies an upper limit on the merger rate of subsolar binaries in the range [220-24200]  Gpc^{-3} yr^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2  M_{⊙}<m_{PBH}<1.0  M_{⊙} is f_{PBH}≡Ω_{PBH}/Ω_{DM}≲6%. This improves existing constraints on primordial black hole abundance by a factor of ∼3. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_{min}=1  M_{⊙}, where f_{DBH}≡Ω_{DBH}/Ω_{DM}≲0.003%. These are the first constraints placed on dissipative dark models by subsolar-mass analyses.

Antimicrobial stewardship in rural and remote primary health care: a narrative review

BACKGROUND

Antimicrobial resistance is an emerging problem worldwide and poses a significant threat to human health. Antimicrobial stewardship programmes are being implemented in health systems globally, primarily in hospitals, to address the growing threat of antimicrobial resistance. Despite the significance of primary health care services in providing health care to communities, antimicrobial stewardship programmes are not well established in this sector, especially in rural and remote settings. This narrative review aims to identify in rural and remote primary health care settings the (1) correlation of antimicrobial resistance with antibiotic prescribing and volume of antibiotic use, (2) appropriateness of antimicrobial prescribing, (3) risk factors associated with inappropriate use/prescribing of antibiotics, and (4) effective antimicrobial stewardship strategies.

METHODS

The international literature was searched for English only articles between 2000 and 2020 using specified keywords. Seven electronic databases were searched: Scopus, Cochrane, Embase, CINAHL, PubMed, Ovid Medline and Ovid Emcare. Publication screening and analysis were conducted using Joanna Briggs Institute systematic review tools.

RESULTS

Fifty-one eligible articles were identified. Inappropriate and excessive antimicrobial prescribing and use directly led to increases in antimicrobial resistance. Increasing rurality of practice is associated with disproportionally higher rates of inappropriate prescribing compared to those in metropolitan areas. Physician knowledge, attitude and behaviour play important roles in mediating antimicrobial prescribing, with strong intrinsic and extrinsic influences including patient factors. Antimicrobial stewardship strategies in rural and remote primary health care settings focus on health care provider and patient education, clinician support systems, utility of antimicrobial resistance surveillance, and policy changes. Results of these interventions were generally positive with decreased antimicrobial resistance rates and improved appropriateness of antimicrobial prescribing.

CONCLUSIONS

Inappropriate prescribing and excessive use of antimicrobials are an important contributor to the increasing resistance towards antimicrobial agents particularly in rural and remote primary health care. Antimicrobial stewardship programmes in the form of education, clinical support, surveillance, and policies have been mostly successful in reducing prescribing rates and inappropriate prescriptions. The narrative review highlighted the need for longer interventions to assess changes in antimicrobial resistance rates. The review also identified a lack of differentiation between rural and remote contexts and Indigenous health was inadequately addressed. Future research should have a greater focus on effective interventional components and patient perspectives.

The impact of infectious diseases consultation on the management and outcomes of Pseudomonas aeruginosa bacteraemia in adults: a retrospective cohort study

BACKGROUND

Pseudomonas aeruginosa bacteraemia (PAB) is associated with high mortality. The benefits of infectious diseases consultation (IDC) has been demonstrated in Staphylococcal aureus bacteraemia and other complex infections. Impact of IDC in PAB is unclear. This study aimed to evaluate the impact of IDC on the management and outcomes in patients with PAB.

METHODS

This is a retrospective cohort single-centre study from 1 November 2006 to 29 May 2019, in all adult patients admitted with first episode of PAB. Data collected included demographics, clinical management and outcomes for PAB and whether IDC occurred. In addition, 29 Pseudomonas aeruginosa (PA) stored isolates were available for Illumina whole genome sequencing to investigate if pathogen factors contributed to the mortality.

RESULTS

A total of 128 cases of PAB were identified, 71% received IDC. Patients who received IDC were less likely to receive inappropriate duration of antibiotic therapy (4.4%; vs 67.6%; p < 0.01), more likely to be de-escalated to oral antibiotic in a timely manner (87.9% vs 40.5%; p < 0.01), undergo removal of infected catheter (27.5% vs 13.5%; p = 0.049) and undergo surgical intervention (20.9% vs 5.4%, p = 0.023) for source control. The overall 30-day all-cause mortality rate was 24.2% and was significantly higher in the no IDC group in both unadjusted (56.8% vs 11.0%, odds ratio [OR] = 10.63, p < 0.001) and adjusted analysis (adjusted OR = 7.84; 95% confidence interval, 2.95-20.86). The genotypic analysis did not reveal any PA genetic features associated with increased mortality between IDC versus no IDC groups.

CONCLUSION

Patients who received IDC for PAB had lower 30-day mortality, better source control and management was more compliant with guidelines. Further prospective studies are necessary to determine if these results can be validated in other settings.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Epidemiology and Microbiology of Severe Community-Acquired Pneumonia in Central Australia: A Retrospective Study

BACKGROUND

Severe community-acquired pneumonia (SCAP) has high mortality and morbidity.

AIMS

To describe the epidemiology and microbiology of SCAP in Central Australia.

METHODS

A retrospective epidemiological study describing the characteristics, incidence rates (IR) and microbiological aetiology of SCAP in Central Australia. Adult patients admitted to Alice Springs Hospital Intensive Care Unit (ICU) between 2011-2014 that fitted the IDSA/ATS definition of SCAP were included. Medical records were reviewed and compared between Indigenous and non-Indigenous patients. Primary outcomes were incidence rate and microbiological aetiology of SCAP. Secondary outcomes were 30-day mortality, and ICU and hospital length of stay (LoS).

RESULTS

A total of 185 patents were included (156 Indigenous, 29 non-Indigenous). The overall SCAP IR per 1000 person-years was 3.24 (3.75 Indigenous and 1.87 non-Indigenous) with an IR difference of 2.71 after adjustment (p<0.001). Those aged ≥50 had an IR 74.8% higher than those younger. Male IR was 50% higher than females. There was a significant difference between Indigenous and non-Indigenous groups for age (48 vs. 64 years), but not for 30-day mortality (7.7% vs. 10.3%), ICU LoS (4.8 vs. 4.6 days) and hospital LoS (10.9 vs. 15.1 days), respectively. Likely causative pathogen(s) were identified in 117 patients; Streptococcus pneumoniae was the most common pathogen (28.2%), followed by Haemophilus influenzae (19.7%), Influenza A/B (16.2%) and Staphylococcus aureus (14.5%).

CONCLUSION

A high incidence of SCAP was observed in Central Australia, disproportionately affecting the Indigenous population. Prevention strategies are imperative, as well as early identification of SCAP and appropriate empiric antibiotic regimens. This article is protected by copyright. All rights reserved.

Optimised dosing of vancomycin in critically ill Indigenous Australian patients with severe sepsis

Vancomycin is a commonly used antibiotic due to the high burden of methicillin-resistant <i>Staphylococcus aureus</i> infections. This study aimed to describe the pharmacokinetics (PK) of vancomycin in Australian Indigenous patients with severe sepsis, and advise an optimal dosing strategy. A population PK study was conducted in a remote Australian intensive care unit (ICU). Serial plasma samples were collected over one to two dosing intervals and assayed by validated chromatography. Concentration-time data collected were analysed using Pmetrics® software. The final population PK model was then used for Monte Carlo dosing simulations to determine optimal loading and intermittent maintenance doses. Fifteen Indigenous subjects were included for analysis with a median (interquartile range, IQR) age, weight and creatinine clearance (CrCL) of 43 (34-46) years, 73 (66-104) kg and 99 (56-139) ml/minute respectively. A two-compartment model described the data adequately. Vancomycin clearance (CL) and volume of distribution of the central compartment (Vc) were described by CrCL and patient weight respectively. Median (IQR) CL, Vc, distribution rate constants from central to peripheral, and from peripheral to central compartments were 4.6 (3.8-5.6) litres per hour, 25.4 (16.1-31.3) litres, 0.46 (0.28-0.52)/hour and 0.25 (0.12-0.37)/hour respectively. No significant interethnic PK differences were observed in comparison to published data. Therapeutic loading doses were significantly dependent on both weight and CrCL, whereas maintenance doses were dependent on CrCL. In the absence of severe renal impairment, initiation of maintenance dose eight hours post-loading dose achieved higher probability of target attainment at 24 hours. This is the first report of vancomycin PK in this patient group.

Prevalence of augmented renal clearance and performance of glomerular filtration estimates in Indigenous Australian patients requiring intensive care admission

Augmented renal clearance (ARC) refers to the enhanced renal excretion of circulating solute commonly demonstrated in numerous critically ill subgroups. This study aimed to describe the prevalence of ARC in critically ill Indigenous Australian patients and explore the accuracy of commonly employed mathematical estimates of glomerular filtration. We completed a single-centre, prospective, observational study in the intensive care unit (ICU), Alice Springs Hospital, Central Australia. Participants were critically ill adult Indigenous and non-Indigenous Australian patients with a urinary catheter in situ. Exclusion criteria were anuria, pregnancy or the requirement for renal replacement therapy. Daily eight-hour measured creatinine clearances (CrCL_m) were collected throughout the ICU stay. ARC was defined by a CrCL_m ≥130 ml/min/1.73 m². The Cockcroft-Gault and Chronic Kidney Disease Epidemiology Collaboration equations were also used to calculate mathematical estimates for comparison. In total, 131 patients were recruited (97 Indigenous, 34 non-Indigenous) and 445 samples were collected. The median (range) CrCL_m was 93.0 (5.14 to 205.2) and 90.4 (18.7 to 206.8) ml/min/1.73 m² in Indigenous and non-Indigenous patients, respectively. Thirty-one of 97 (32%) Indigenous patients manifested ARC, compared to 7 of 34 (21%) non-Indigenous patients (<i>P</i>=0.21). Younger age, major surgery, higher baseline renal function and an absence of diabetes were all associated with ARC. Both mathematical estimates manifest limited accuracy. ARC was prevalent in critically ill Indigenous patients, which places them at significant risk of underdosing with renally excreted drugs. CrCL_m should be obtained wherever possible to ensure accurate dosing.

Optimising meropenem dosing in critically ill Australian Indigenous patients with severe sepsis

Currently there are no pharmacokinetic (PK) data to guide antibiotic dosing in critically ill Australian Indigenous patients with severe sepsis. This study aimed to determine whether the population pharmacokinetics of meropenem were different between critically ill Australian Indigenous and critically ill Caucasian patients. Serial plasma and urine samples as well as clinical and demographic data were collected over two dosing intervals from critically ill Australian Indigenous patients. Plasma meropenem concentrations were assayed by validated chromatography. Concentration-time data were analysed with data from a previous PK study in critically ill Caucasian patients using Pmetrics. The population PK model was subsequently used for Monte Carlo dosing simulations to describe optimal doses for these patients. Six Indigenous and five Caucasian subjects were included. A two-compartment model described the data adequately, with meropenem clearance and volume of distribution of the central compartment described by creatinine clearance (CL_Cr) and patient weight, respectively. Patient ethnicity was not supported as a covariate in the final model. Significant differences were observed for meropenem clearance between the Indigenous and Caucasian groups [median 11.0 (range 3.0-14.1) L/h vs. 17.4 (4.3-30.3) L/h, respectively; P <0.01]. Standard dosing regimens (1 g intravenous every 8 h as a 30-min infusion) consistently achieved target exposures at the minimum inhibitory concentration breakpoint in the absence of augmented renal clearance. No significant interethnic differences in meropenem pharmacokinetics between the Indigenous and Caucasian groups were detected and CL_Cr was found to be the strongest determinant of appropriate dosing regimens.

Interethnic differences in pharmacokinetics of antibacterials

BACKGROUND

Optimal antibacterial dosing is imperative for maximising clinical outcome. Many factors can contribute to changes in the pharmacokinetics of antibacterials to the extent where dose adjustment may be needed. In acute illness, substantial changes in important pharmacokinetic parameters such as volume of distribution and clearance can occur for certain antibacterials. The possibility of interethnic pharmacokinetic differences can further complicate attempts to design an appropriate dosing regimen. Factors of ethnicity, such as genetics, body size and fat distribution, contribute to differences in absorption, distribution, metabolism and elimination of drugs. Despite extensive previous work on the altered pharmacokinetics of antibacterials in some patient groups such as the critically ill, knowledge of interethnic pharmacokinetic differences for antibacterials is limited.

OBJECTIVES

This systematic review aims to describe any pharmacokinetic differences in antibacterials between different ethnic groups, and discuss their probable mechanisms as well as any clinical implications.

METHODS

We performed a structured literature review to identify and describe available data of the interethnic differences in the pharmacokinetics of antibacterials.

RESULTS

We found 50 articles that met our inclusion criteria and only six of these compared antibacterial pharmacokinetics between different ethnicities within the same study. Overall, there was limited evidence available. We found that interethnic pharmacokinetic differences are negligible for carbapenems, most β-lactams, aminoglycosides, glycopeptides, most fluoroquinolones, linezolid and daptomycin, whereas significant difference is likely for ciprofloxacin, macrolides, clindamycin, tinidazole and some cephalosporins. In general, subjects of Asian ethnicity achieve drug exposures up to two to threefold greater than Caucasian counterparts for these antibacterials. This difference is caused by a comparatively lower volume of distribution and/or drug clearance.

CONCLUSION

Interethnic pharmacokinetic differences of antibacterials are likely; however, the clinical relevance of these differences is unknown and warrants further research.

Responses of starburst amacrine cells to prosthetic stimulation of the retina

Recent advances in the design and development of retinal implants have made these devices a promising therapeutic strategy for restoring sight to the blind. Over the last decade a plethora of studies have investigated the responses of the retinal ganglion cells (RGCs) to electrical stimulation under a variety of stimulus configurations. Similar to the RGCs, the amacrine cells also survive in large numbers following retinal neural degeneration. However, with the exception of two previous reports, where the responses of the amacrine cells were measured indirectly, these cells have thus far received little attention in the context of prosthetic stimulation. In this study we focused on the starburst amacrine cells (SACs), a particularly well-characterized amacrine cell among the approximately two-dozen types known to exist in the retina. Using whole-cell patch clamp recordings in the whole-mount rabbit retina, we investigated the temporal responses of the SACs following subretinal biphasic pulse stimulation. These cells responded to the stimuli with oscillatory membrane potentials that lasted for tens to hundreds of milliseconds, with the response amplitude increasing as a function of stimulus strength. Furthermore, the SAC responses originated primarily from the presynaptic inputs they receive, rather than through direct activation of these cells by the electrical stimuli.

High-dose corticosteroids with or without etanercept for the treatment of idiopathic pneumonia syndrome after allo-SCT

Idiopathic Pneumonia Syndrome (IPS) is a common complication after allo-SCT and results in high mortality rates. Conventional treatment for IPS typically includes supportive care and high-dose corticosteroids (CS). Data suggests that TNF-α is important in the pathogenesis of IPS and that the TNF-α inhibitor etanercept may be useful for IPS treatment. We performed a retrospective comparison of consecutive patients treated at our center for IPS with CS only from 1999 to 2003 (group 1, n=22) or CS plus etanercept from 2004 to 2007 (group 2, n=17). In all, 18% of patients in group 1 vs 53% in group 2 were successfully taken off respiratory support and discharged from the hospital (P=0.039). OS was significantly better for recipients of CS plus etanercept (P=0.003). The estimated survival at 28 days and 2 years after IPS was 36.4% (95% CI 17-56%) and 9.1% (95% CI 2-25%) for group 1 and 88.2% (95% CI 61-97%) and 18% (95% CI 4-38%) for group 2, respectively. Our retrospective comparison suggests that the addition of etanercept to CS for IPS improves response rates and OS. However, outcomes remain limited in both groups, highlighting the need for more effective interventions to treat early and late complications of IPS.

Discrete cortical responses from multi-site supra-choroidal electrical stimulation in the feline retina

Exploration into electrical stimulation of the retina has thus far focussed primarily upon the development of prostheses targeted at one of two sites of intervention - the epi- and sub-retinal surfaces. These two approaches have sound, logical merit owing to their proximity to retinal neurons and their potential to deliver stimuli via the surviving retinal neural networks respectively. There is increasing evidence, however, that electric field effects, electrode engineering limitations, and electrode-tissue interactions limit the spatial resolution that once was hoped could be elicited from electrical stimulation at epi- and sub-retinal sites. An alternative approach has been proposed that places a stimulating electrode array within the supra-choroidal space - that is, between the sclera and the choroid. Here we investigate whether discrete, cortical activity patterns can be elicited via electrical stimulation of a feline retina using a custom, 14 channel, silicone rubber and Pt electrode array arranged in two hexagons comprising seven electrodes each. Cortical responses from Areas 17/18 were acquired using a silicon-based, multi-channel, penetrating probe developed at IMTEK, University of Freiburg, within the European research project NeuroProbes. Multi-unit spike activity was recorded in synchrony with the presentation of electrical stimuli. Results show that distinct cortical response patterns could be elicited from each hexagon separated by 1.8 mm (center-to-center) with a center-to-center electrode spacing within each hexagon of 0.55 mm. This lends support that higher spatial resolution may also be discerned.

Direct activation of retinal ganglion cells with subretinal stimulation

Recent advances in the design and implementation of vision prostheses have made these devices a promising therapeutic option for restoring sight to blind patients in the near future. The success of vision prostheses in providing clinically useful vision, however, depends critically on our understanding of the retinal neural mechanisms evoked during electrical stimulation, and how these mechanisms can be controlled precisely to elicit the desired visual percept. We demonstrate here that subretinal stimulation can reliably elicit stimulus- locked short latency (< or = 2 ms) responses. To our knowledge, this is the first report of such responses using the subretinal paradigm. These responses could be readily distinguished from within the stimulus artifacts using cell-attached extracellular recording or whole-cell patch clamp. The thresholds for these short latency responses were determined for ON, OFF and ON- OFF type retinal ganglion cell classes across cathodic biphasic pulses of 0.1-5.0ms. No significant difference was found for the mean latency and the threshold for the different cell types over the pulse range tested.

A wearable real-time image processor for a vision prosthesis

Rapid progress in recent years has made implantable retinal prostheses a promising therapeutic option in the near future for patients with macular degeneration or retinitis pigmentosa. Yet little work on devices that encode visual images into electrical stimuli have been reported to date. This paper presents a wearable image processor for use as the external module of a vision prosthesis. It is based on a dual-core microprocessor architecture and runs the Linux operating system. A set of image-processing algorithms executes on the digital signal processor of the device, which may be controlled remotely via a standard desktop computer. The results indicate that a highly flexible and configurable image processor can be built with the dual-core architecture. Depending on the image-processing requirements, general-purpose embedded microprocessors alone may be inadequate for implementing image-processing strategies required by retinal prostheses.

A six-panel PCR of both plasma and blood for EBV-DNA as tumor marker for nasopharyngeal carcinoma patients treated in the United States

e17014

Background: Studies of plasma from nasopharyngeal carcinoma (NPC) patients from endemic regions demonstrate that circulating DNA derived from EBV may be used as a tumor marker, but data from non-endemic regions or in whole blood are limited. Methods: ViraCor Laboratories (Lee's Summit, MO) performed PCR for EBNA, EBER, and LMP on both plasma and whole blood of 11 NPC patients undergoing therapy at the Hospital of the University of Pennsylvania. Results were correlated with disease status via review of chart records and imaging reports. Results: 7 of 11 patients tested were positive for circulating EBV derived DNA. 2 patients were treated with induction chemotherapy with suppression to 0 copies of circulating DNA for all plasma measures, but not whole blood measures (LMP 0, EBER 100 and EBNA 200 copies for one patient and LMP 100, EBNA 100 and EBER 300 copies for the other). The first of these patients remains free of disease but the other retains a large mass believed to be active disease, but which has not grown over 8 months following therapy. 5 patients, including the 2 patients treated with induction therapy, were treated with chemoradiotherapy. PCR following therapy was negative on all plasma measures for the 4 patients who remain free of disease (at intervals of 7, 12, 13 and 16 months). 2 of these patients retained low-level EBV on at least 1 whole-blood measure–1 for EBNA alone (100 copies) and the other for both EBER and EBNA (300 and 100 copies). 2 patients were treated for metastatic disease. 3 episodes of progression were all accompanied by increases in plasma EBV (EBNA from 13,700 to 21,100 with EBER 1600 to 9400 and EBNA 1800 to 2200 to 3000 with EBER 100 to 100 to 500). Conclusions: This pilot data on a population treated in the United States is consistent with larger data sets obtained in endemic regions demonstrating that EBV is an effective tumor marker for prognosis and to follow therapy. It is the first to demonstrate greater specificity of plasma measures over whole blood measures, and it raises the hypothesis that whole blood measures may be more sensitive. Further prospective study is warranted in non-endemic populations both to validate the measure and to facilitate translational research into biologic factors driving the behavior of these tumors.

[Table: see text]

Variability in the biological response to anti-CD20 B cell depletion in systemic lupus erythaematosus

OBJECTIVE

To study the effects in systemic lupus erythaematosus (SLE) of B cell directed therapy with rituximab, a chimeric monoclonal antibody directed at CD20+ B cells, without concomitant immunosuppressive therapy in mild to moderate SLE.

METHODS

Patients (n=24) with active SLE and failure of >or=1 immunosuppressive were recruited from three university centres into this phase I/II prospective open-label study. Patients were followed for 1 year to assess safety, efficacy and biological effects.

RESULTS

In total, 18 of the patients scheduled to receive the full lymphoma dose of rituximab were evaluable for B cell levels in peripheral blood. Of these, 17 had effective CD19+ B cell depletion (<5 cells/microl). However, six of the depleted patients showed B cell return before 24 weeks. A total of 70% of patients improved by week 55, as defined by an SLE Disease Activity Index (SLEDAI) score improvement of >or=2 units from baseline. The degree of CD19+ B cell depletion was correlated with SLEDAI improvement at week 15 (r=0.84). In general, rituximab infusions were well tolerated. Approximately a third of the patients developed human anti-chimeric antibody (HACA) titres, which correlated with poor B cell depletion. Most patients (9 of 14) did not respond to immunisations with Pneumovax and tetanus toxoid.

CONCLUSIONS

Rituximab is a promising new therapy for SLE. The variability of responses in patients with SLE may be related to HACA formation. The failure to respond to immunisations is surprising, in view of the apparently low risk of infections. Better biological markers are necessary to follow these patients during treatment.

Prognostic value of FDG-PET scan imaging in lymphoma patients undergoing autologous stem cell transplantation

We conducted a retrospective analysis of 50 lymphoma patients (Hodgkin's disease and non-Hodgkin's lymphoma) who had an 18F-fluoro-deoxyglucose positron emission tomography (FDG-PET) scan after at least two cycles of salvage chemotherapy and before autologous stem cell transplantation (ASCT) at our institution. The patients were categorized into FDG-PET negative (N = 32) and positive (N = 18) groups. The median follow-up after ASCT was 19 months (range: 3-59). In the FDG-PET-negative group, the median progression-free survival (PFS) was 19 months (range: 2-59) with 15 (54%) patients without progression at 12 months after ASCT. The median overall survival (OS) for this group was not reached. In the FDG-PET-positive group, the median PFS was 5 months (range: 1-19) with only one (7%) patient without progression at 12 months after ASCT. The median OS was 19 months (range: 1-34). In the FDG-PET-negative group, chemotherapy-resistant patients by CT-based criteria had a comparable outcome to those with chemotherapy-sensitive disease. A positive FDG-PET scan after salvage chemotherapy and prior ASCT indicates an extremely poor chance of durable response after ASCT.

Nonmyeloablative allogeneic stem cell transplantation for refractory Hodgkin's lymphoma complicated by interleukin-2 responsive progressive multifocal leukoencephalopathy

Nonmyeloablative allogeneic stem cell transplantation (NMASCT) can be used to exploit the graft-versus-tumor (GVT) potential of allogeneic donor cells in the setting of reduced conditioning regimen toxicity. This approach is particularly attractive for patients who have received extensive prior therapy and are poor candidates for traditional allogeneic stem cell transplantation. However, toxicity in heavily pretreated patients remains uncertain. Additional immunosuppression in already immunocompromised patients may result in unexpected toxicity. We report a case of probable progressive multifocal leukoencephalopathy (PML) responsive to interleukin-2 (IL-2) following a NMASCT in a 29-year-old woman with relapsed Hodgkin's lymphoma. The patient developed severe neurological symptoms approximately 6 weeks following NMASCT associated with low CD4+ cell counts and magnetic resonance imaging (MRI) was consistent with PML. IL-2 therapy resulted in increasing CD4+ counts and progressive resolution of neurological symptoms. Disruption of IL-2 therapy led to neurological deterioration, which responded to reinstitution of IL-2 therapy. The patient's lymphoma initially progressed following NMASCT, but has responded to donor leukocyte infusions (DLI). This case reiterates the potent GVT potential of NMASCT in patients with Hodgkin's disease. However, it demonstrates the potential for severe complications related to immunosuppression, especially in heavily pretreated patients. The toxicity after NMASCT should not be understated and will need to be explored further.

Allogeneic cell therapy for patients who relapse after autologous stem cell transplantation

Allogeneic donor leukocytes can be used after nonmyeloablative conditioning to exploit their graft-versus-tumor (GVT) activity in the setting of reduced conditioning-regimen toxicity. This approach may be particularly useful for patients who relapse after autologous stem cell transplantation (SCT). However, GVT activity, toxicity, and ability to establish mixed chimerism may differ in patients who were heavily pretreated prior to SCT compared with patients treated earlier in the course of their disease. We have performed a series of studies of nonmyeloablative allogeneic transplantation and present data on the subset of 14 patients treated for relapse after autologous SCT: 4 patients received no conditioning and unstimulated donor leukocyte infusions (DLI), 10 patients received conditioning with fludarabine and cyclophosphamide followed by unstimulated or granulocyte-colony-stimulating factor (G-CSF)-stimulated allogeneic peripheral blood stem cells (PBSCs), 4 patients received no graft-versus-host disease (GVHD) prophylaxis, and 10 patients received cyclosporine GVHD prophylaxis. All but 1 patient had sustained donor chimerism at least 30 days after allogeneic cell therapy (ACT), and 8 patients had more than 80% donor chimerism after ACT. Acute GVHD developed in 11 patients (grade III-IV, n = 6). Aplasia was more frequent in the patients receiving unstimulated PBSCs, despite the development of mixed chimerism. There were 6 complete responses and 4 partial responses; response was independent of conditioning and growth-factor stimulation of the donor graft. Five patients died of treatment-related causes and 4 patients died from progressive disease. Four patients remained alive 27 to 194 weeks (median, 66 weeks) after ACT. Prior autologous SCT may define a subset of patients at particularly high risk for GVHD and other toxicity after ACT. However, these data show that ACT with either DLI or G-CSF-stimulated blood cells results in direct GVT activity in some patients with Hodgkin's disease, myeloma, and non-Hodgkin's lymphoma, even after relapse from autologous SCT. Most patients developed donor chimerism with minimal conditioning. Alternative prophylactic regimens that control GVHD while maintaining GVT are needed to improve outcomes in these heavily pretreated patients.

Determination of enantiomers in a synthetic argininal peptide using capillary zone electrophoresis and high-performance liquid chromatography

SCH 201781 is a synthetic argininal peptide containing two chiral centers and an aromatic sulfonamide group. It can exist as four reversible forms, the aldehyde, the hydrate, and two diastereomeric aminals. Capillary zone electrophoresis (CZE) and reversed-phase high-performance liquid chromatographic (HPLC) methods were developed to separate and quantitate the enantiomers in SCH 201781. Comparable results were obtained using both methods. The CZE method uses direct injection, while the HPLC method requires a precolumn derivatization and is more time consuming. The CZE method provides superior sensitivity to the HPLC method. Both methods were shown to be precise and reproducible.

Rituximab (anti-CD20 monoclonal antibody) therapy for progressive intermediate-grade non-Hodgkin's lymphoma after high-dose therapy and autologous peripheral stem cell transplantation

We evaluated the response and toxicity of rituximab in the setting of progressive intermediate grade non-Hodgkin's lymphoma (NHL) after autologous peripheral stem cell transplantation (PSCT). Seven patients with a median age of 59 years (45-62), ECOG performance status 0-1, and CD20-positive diffuse large cell lymphoma with progression after PSCT were treated. All patients initially received 4-weekly infusions of rituximab (375 mg/m2). The maximum response was three CR and four PR. Median progression-free survival was 197 days (range 60-282). With a median follow-up of 204 (115-299) days, the patients' disease status is classified as two CR, one PR, and four PD. Four of five patients with ECOG performance status of 1 prior to treatment showed improvement to status 0 after treatment with rituximab. While follow-up is short, these results suggest that rituximab has significant activity in intermediate-grade non-Hodgkin's lymphoma that has relapsed after PSCT.

A distributed control model for the air-righting reflex of a cat

A multisegment, multijoint model of a falling animal is presented to examine the effectiveness of a two-stage control scheme in a zero-momentum self-righting maneuver. The model contains a much larger number of degrees of freedom than is required to execute a self-righting maneuver and is thus capable of providing multiple solutions for the same task. The decentralized control scheme is designed to achieve gross turning in minimum time and to maintain a steady orientation relative to gravity after the turn has been achieved. The scheme is able to determine the sequence of steps necessary to execute the motor task and also incorporates learning features. Results from various simulations are presented and their implications discussed.

Stereotactic radiosurgery for brain metastases: comparison of lung carcinoma vs. non-lung tumors

In the medical literature, stereotactic radiosurgery (SRS) for brain metastases results in rates of local control of 65 to 85 %. To define patient selection criteria, we measured the survival in a population with a high proportion of non-small cell lung carcinoma (NCS lung) metastases that occurred soon after primary diagnosis. Between 9/89 and 10/93 30 adults (21 M, 9 F) had SRS for metastatic NSC lung carcinoma (14 patients) vs. non-lung carcinomas (16 patients having breast (3), renal (3), melanoma (3), GI (2, thyroid (1) or carcinoma of unknown origin (4)). The metastases were solitary for 22 patients and multiple for 8 patients. Average ages (y) (+/-SD) were 58.6+/-10.4 for NSC lung patients and 53.4+/-12.5 (p = 0.32) for non-lung patients. The average interval (months) from diagnosis of the primary to metastasis was 23.8+/-41.4 for all patients. This interval was shorter for NSC lung patients: 3.1+/-6.0 vs. 48.0+/-51.7 (p < 0.001) for non-lung patients. Twenty seven patients had conventional radiotherapy (XRT) before (24 patients) or after (3 patients) SRS. Doses (cGy) were 3303+/-841 for 13 NSC lung patients and 4256+/-992 for 14 non-lung patients (p = 0.034). The median time from primary diagnosis to SRS was shorter for the NSC lung patients (11 mo) compared to the non-lung patients (35 mo). SRS was given for recurrence of metastases after XRT for 11/14 NSC lung patients and 13/16 non-lung patients. The doses (cGy) of SRS were 1579+/-484 vs. 1682+/-476 (p=0.45) for the NSC lung and non-lung groups, respectively. After SRS a decrease in metastasis diameter was observed in 10 of 14 NSC lung patients vs. 12 of 16 non-lung patients (p=0.85 Chi-square). Twenty-seven of the 30 patients have died. For all patients, the median survival after diagnosis of the primary and after radiosurgery was 31.3 and 8.4 months, respectively. The median survival (95% CI) from primary diagnosis was 24.3 months (13.2-27.3) for NSC lung patients and 46.5 months (39.2-65.5) for non-lung patients (p=0.005 logrank test). The median survival (95% CI) after SRS was 7.9 months (3.0-14.3) for the NSC lung patients and 8.4 (2.9-11.9) months for the non-lung patients (p=0.98 logrank test). Within the two groups, no difference in survival was observed for patients who had SRS sooner (< 1 yr for NSC lung; < 3 yr for non-lung) after primary diagnosis: 9.3 vs. 6.5 mo for NSC lung (p=0.21) and 10.5 vs. 7.2 mo for non-lung (p=0.87). In this series, the shortened intervals from primary diagnosis to SRS for NSC lung metastases was associated with post-SRS survivorship that was equivalent to the more favorable non-lung group.

Functional outcome and patient satisfaction in total knee patients over the age of 75

Seventy-four patients, age 75 or older, who had undergone 98 primary total knee arthroplasties were evaluated in a retrospective cohort study, with validated questionnaires that assessed self-reported pain, physical function, mental health, and satisfaction. Average follow-up period was 34 months (range, 12-67 months). Overall, 90.8% reported improvement, 88.8% were satisfied with the results of surgery, and 91.8% felt they had made the right decision. Dissatisfaction with the results correlated with poorer mental health scores, decreased physical function, and increased bodily pain scores (P < .05). Satisfaction was correlated with better pain scores on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and SF-36 (P < .05) but not with Hospital for Special Surgery scores (P = .328). Poor surgical results leading to revision surgery (5%) were associated with preoperative deformity greater than 20 degrees. Based on this patient-assessed outcome analysis, total knee arthroplasty is a worthwhile and beneficial procedure in the elderly.

Morphine-augmented cholescintigraphy: its efficacy in detecting acute cholecystitis

Cholescintigrams were performed in 158 patients suspected of having acute cholecystitis after administration of 185 Mbq (5 mCi) of 99mTc-mebrofenin or disofenin. Morphine sulfate, 0.04 mg/kg was given intravenously if there was nonvisualization of the gallbladder at 40-60 min provided that radiotracer was seen within the small bowel. Acute cholecystitis was deemed present if there was nonvisualization of the gallbladder 30 min post-morphine administration; no cystic duct obstruction was present if the gallbladder was demonstrated pre- or post-morphine administration. A final diagnosis was estimated in 51 postoperative patients histologically, the remainder having their final diagnosis gleaned from their medical records. The sensitivity, specificity, positive and negative predictive value of morphine-augmented cholescintigraphy in detecting acute cholecystitis was 94.6, 99.1, 97.2, and 98.3%, respectively. These findings indicate that morphine-augmented cholescintigraphy detects acute cholecystitis with as high a degree of accuracy as conventional hepatobiliary scintigraphy, yet requires only 1.5 hr to establish the diagnosis.

Indium-111-leukocyte imaging in acute cholecystitis

Eleven patients with suspected acute cholecystitis underwent sequential 99mTc-iminodiacetic derivative (IDA) and 111In-white blood cell (WBC) imaging to determine if 111In-WBCs accumulate within an acutely inflamed hemorrhagic gallbladder wall and, thus, could be employed as a reasonable alternative to 99mTc-IDA scintigraphy in detecting acute cholecystitis. Seven patients had surgically confirmed acute cholecystitis. Of these cases, five had a true-positive 99mTc-IDA and 111In-WBC, one an indeterminate 111In-WBC and true-positive 99mTc-IDA, and one a true-positive 111In-WBC and false-negative 99mTc-IDA scan. The remaining four patients did not have acute cholecystitis. All visualized their gallbladder within 1 hr after 99mTc-IDA administration and none had 111In-WBC gallbladder wall uptake. Both 111In-WBC and 99mTc-IDA scintigraphy accurately detected acute cholecystitis: hepatobiliary scintigraphy demonstrated a cystic duct obstruction and 111In-WBC imaging detected the inflammatory infiltrate within the gallbladder wall. The sensitivity and specificity of each was 86% and 100%, respectively.

Clinical studies of cancer radioimmunodetection with carcinoembryonic antigen monoclonal antibody fragments labeled with 123I or 99mTc

Seventy-three patients with diverse cancers containing carcinoembryonic antigen received 123I-labeled anti-carcinoembryonic antigen monoclonal antibody F(ab')2 fragment [38 patients], 99mTc-labeled anti-carcinoembryonic antigen monoclonal antibody Fab' fragment [23 patients], or both reagents at different times [6 patients] for evaluation of antibody targeting and imaging [radioimmunodetection (RAID)], using planar and single-photon emission computed tomography. The results indicated that antibody fragments are preferred for early tumor imaging (within 24 h). Rapid targeting and clearance from blood and normal organs of the antibody fragments (blood median t1/2 elimination of 26.5 and 13.2 h for the F(ab')2 and Fab' fragments respectively) permitted the use of short-lived radionuclides, such as 123I (13.3 h) and 99mTc (6 h), and confirmed that selective antibody accretion in tumors occurred very soon after administration, such as between 2 and 5 h. Scan interpretations at 24 h for the 123I-labeled F(ab')2 and at 2-5 h for the 99mTc-labeled Fab' revealed overall sensitivities, on a tumor site basis, of 95.9 and 94.9%, respectively. On a site basis, the overall accuracies were 94.2 and 93.8% for the 123I and 99mTc immunoconjugates, respectively. In the 6 patients studied with both radioimmunoconjugates, a high concordance in detection was found. Both imaging agents also revealed a high number of putatively new tumor sites not disclosed by other radiological methods at the time of the RAID studies, of which 40.0 and 20.5% were subsequently confirmed as tumor for the 123I and 99mTc agents, respectively, within an 11-month follow-up period. This represented 24 proven occult tumor sites in 19 patients given the 123I-immunoconjugate and 16 proven occult tumor sites in 9 patients receiving the 99mTc agent. The new lesions were found up to 17 and 7 months earlier for 123I-RAID and 99mTc-RAID, respectively, than with other detection methods. The smallest tumors identified were below 0.5 cm, especially with the 99mTc immunoconjugate and single-photon emission computed tomography imaging. The findings of this study confirm previous evidence that RAID is a safe and a potentially useful new method of cancer detection. Despite the excellent results with the 123I-F(ab')2 antibody fragment, its poor availability and high cost limit its clinical use. Therefore, the 99mTc agent, which is made by an instant, 1-step, 1-vial, direct labeling method, appears to be the method of choice for rapid and accurate detection of cancer by RAID.

A two-bit contention-based TDMA technique for data transmissions

The performance of a contention-based TDMA technique is studied in this paper. The frame structure of the time-axis is similar to [1] and [2]. The protocols proposed in [1],[2] and here are all active multiaccess techniques. The protocol in [1] is contention free and suitable for heavy traffic while a contention-based protocol suitable for light traffic is considered in [2]. The protocol to be studied in this paper is also contention in nature and performs considerably better than [2]. This protocol is less complicated than [1] and out-performs [1] unless traffic is very high. Performance analyses, both transient and steady-state, have been successfully completed. Results obtained include average queue length and packet delay, etc. The validity of analysis is also verified by computer simulations.

Control of glycoprotein synthesis. The in vitro synthesis by hen oviduct membrane preparations of hybrid asparagine-linked oligosaccharides containing 5 mannose residues

Hen oviduct membranes were incubated with UDP-N-acetyl-D-[14C]glucosamine and [3H]GlcNAc beta 1-2Man alpha 1-3[Man alpha 1-6(Man alpha 1-3)Man alpha 1-6]Man beta 1-4GlcNAc beta 1-4GlcNAc-Asn (glycopeptide Gn(I)M5). Two double labeled products were obtained, both containing 5 Man and 4 GlcNAc residues. In order to separate these isomeric components, the mixture was treated with rat liver Golgi-rich membranes as a source of mannosidase II. One of the isomers was degraded by mannosidase action while the other was not, thereby allowing separation of two products (A and B). Product A was shown to be [3H]GlcNAc beta 1-2[( 14C] GlcNAc beta 1-3,4, or 6)Man alpha 1- 3Man beta 1-4GlcNAc beta 1-4GlcNAc, proving that hen oviduct membranes were capable of incorporating GlcNAc in beta-linkage into the Man alpha 1-3- residue of Gn(I)M5. Product B was identified as [3H]GlcNAc beta 1-2Man alpha 1-3[( 14C]GlcNAc beta 1-4)-[Man alpha 1-3)Man alpha 1-6]Man beta 1-4GlcNAc beta 1- f4GlcNAc , showing that hen oviduct membranes could incorporate a bisecting GlcNAc residue (linked beta 1-4 to the beta-linked Man) into Gn(I)M5. The ability of hen oviduct to carry out these two reactions in vitro supports the hypothesis first suggested by Harpaz and Schachter ( Harpaz , N., and Schachter , H. (1980) J. Biol. Chem. 255, 4894-4902) that the synthesis of bisected hybrid oligosaccharides is controlled by the insertion of a bisecting GlcNAc residue into Gn(I)M5. The presence of a bisecting GlcNAc residue prevents mannosidase II action and the synthetic pathway is therefore committed to hybrid oligosaccharide synthesis.

[Modulation of alkaline phosphatase by butyrate and prednisolone in uterine cervical cancer cell line (SKG-III)]

The production of late placental alkaline phosphatase (ALP) isoenzyme and the co-presence of a small amount of tissue-unspecific ALP isoenzyme was confirmed in the newly established uterine cervical epidermoid cancer cell line SKG-III. Sodium butyrate (3mM), which has been shown to modulate oncodevelopmental gene expression, was examined after introduction of the agents into confluent cultures. 72 hours after the first sodium butyrate treatment, the amount (per mg cell protein) of total ALP activity increased to 5 times that of control cells and tissue-unspecific insoenzyme occupied about two thirds of the concentration of the modulated ALP. Treatment of SKG-III cells with prednisolone (5 micrograms/ml) for 48 hours caused a 3.5 times increase in total ALP activity, and most of the modulated ALP was occupied by late placental isoenzyme. From these data, it was concluded that sodium butyrate mainly induced tissue-unspecific isoenzyme, while prednisolone induced late placental isoenzyme. The results suggested that SKG-III cells had at least two ALP isoenzyme genes and chemical agents such as sodium butyrate or prednisolone could modulate the ALP isoenzyme profile of these cultured cells in vitro.

The relative capacity of corneal, heart, kidney and skin cells to stimulate allogeneic lymphocytes

In stimultaneous experiments, the ability of inbred Wistar-Furth rat corneal cells to stimulate inbred Fisher rat lymphocytes in mixed culture was compared with the stimulatory capacity of the same number of Wistar-Furth skin, kidney, heart and lymphocyte cells. The tissue cells were dissociated and after inhibition by mitomycin C cultured with an equal number of allogeneic spleen lymphocytes for 5 days. In all of these mixed cell cultures, the allogeneic lymphocytic response was mainly to the major Ag-B2 histocompatibility antigen. The stimulatory effect of corneal cells was found to be the same as that of heart, kidney and skin cells. The data indicate a lack of differences between the density of histocompatibility antigens on the surfaces of these cells.