Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Thrombosis with thrombocytopenia syndrome (TTS) following adenovirus vector COVID-19 vaccination in Canada

INTRODUCTION

Identifying and monitoring adverse events following vaccination contributed to the safety and effectiveness of COVID-19 mass vaccination campaigns. In March 2021, international reports emerged of an adverse event following vaccination with adenovirus vector COVID-19 vaccines (ChAdOx1-S [recombinant] and Ad26.COV2.S) of thrombosis with low platelet counts, referred to as thrombosis with thrombocytopenia syndrome (TTS). We described TTS reports in Canada following adenovirus vector COVID-19 vaccines and investigated whether the observed number of events were higher than expected.

METHODS

Reports of TTS following receipt of ChAdOx1-S [recombinant] or Ad26.COV2.S meeting the Canadian case definition for TTS and diagnostic certainty levels 1-3 of the Brighton Collaboration case definition, submitted to the Canadian Adverse Events Following Immunization Surveillance System and Canada Vigilance Database between February 26, 2021 and October 31, 2022 were included. Demographics and characteristics of the TTS reports are described along with an analysis comparing the observed number of reports to the expected number.

RESULTS

As of October 31, 2022, 56 reports of TTS following administration of ChAdOx1-S [recombinant] and no reports following Ad26.COV2.S vaccines were reported in Canada, of which 37 had functionally positive anti-PF4 antibodies. The median age was 56 years; males accounted for 54 % of reports. Five deaths were reported. The observed number of reports exceeded the expected for all ages and sexes combined, as well as for males aged 30-49 and 60-69 years, and females aged 40-59 years.

CONCLUSION

Based on international surveillance data, Canada evaluated a statistical signal of TTS following adenovirus vector vaccines. The investigation of this signal demonstrated how post-market vaccine safety surveillance systems were successful in investigating rare adverse events during the rollout of COVID-19 vaccines in Canada. As adenovirus vector vaccines continue to be administered, characterization of the association between the vaccine and TTS informs immunization programs and policies.

Low genetic confirmation rate in South Indian subjects with a clinical diagnosis of maturity-onset diabetes of the young (MODY) who underwent targeted next-generation sequencing for 13 genes

PURPOSE

To screen for maturity-onset diabetes of the young (MODY) variants in subjects with an early age of onset and positive family history of diabetes mellitus.

METHODS

60 subjects with onset of diabetes between 3 and 30 years of age and parental history (onset < 35 years) of diabetes were recruited after excluding autoimmune, pancreatic and syndromic forms of diabetes. Detailed pedigree chart and clinical data were recorded. MODY genetic testing (MODY 1-13) was performed and variant classification was done adhering to the ACMG guidelines.

RESULTS

Baseline characteristics of subjects were as follows: mean age of onset of diabetes 19.9 ± 7 years, mean duration of diabetes 6.3 ± 6.8 years, BMI 23.3 ± 3 kg/m² and C-peptide 1.56 ± 1.06 nmol/l. Four out of sixty (6.6%) were positive for variants classifiable as pathogenic/likely pathogenic: one patient with HNF4Ac.691C > T, (p.Arg231Trp), two with HNF 1A c.746C > A(p.Ser249Ter) and c.1340C > T(p.Pro447Leu), and one with ABCC8 c.4544C > T (p.Thr1515Met). MODY 1 and MODY 3 variants were documented in the paediatric age group (< 18 years).

CONCLUSION

A genetic diagnosis of MODY could be confirmed in only 6.6% (4/60) of patients clinically classifiable as MODY. This is less than that reported in clinically diagnosed MODY subjects of European descent. Newly published population data and more stringent criteria for assessment of pathogenicity and younger age of onset of type 2 diabetes in Indians could have contributed to the lower genetic confirmation rate. Apart from variants in the classical genes (HNF1A, HNF4A), a likely pathogenic variant in a non-classical gene (ABCC8) was noted in this study.

Evaluation of Same-Day versus Next-Day Implantation of Intracanalicular Dexamethasone for the Control of Postoperative Inflammation and Pain Following Cataract Surgery

Purpose

To evaluate the safety and efficacy of a sustained-release intracanalicular dexamethasone insert for postoperative inflammation and pain implanted in a clinical setting preoperatively or on postoperative day 1.

Methods

Single-site, retrospective, contralateral eye study of patients undergoing cataract surgery. Included were subjects with a dexamethasone intracanalicular insert implanted in the clinic immediately prior to surgery in one eye (same-day) and on postoperative day 1 (POD1) in the contralateral eye. The primary outcome measure was the resolution of anterior chamber inflammation at 1 week postoperative. Secondary outcome measures included proportion of eyes requiring additional therapy for pain and inflammation through 1 month as well as the number of eyes with IOP spikes above baseline. Safety measures included adverse events through 1 month postoperative.

Results

Sixty-two eyes of 31 subjects were included in the case series. At 1 week postoperative, 52% of the eyes (n = 16) achieved complete resolution of inflammation in the same-day group and 58% (n = 18) met this endpoint at 1 week in the POD1 group. One subject in the same-day group required additional therapy for rebound inflammation and no eyes required additional therapy in the POD1 group. There were no reports of pain at 1 week or 1 month in either group. There were no implant-related adverse events in either group.

Conclusion

The favorable results of this study indicate that the sustained-release dexamethasone insert can be safely implanted in the clinic either preoperatively on the day of surgery or on postoperative day 1 for the control of pain and inflammation following cataract surgery.

Knowledge, Attitude and Practice on Covid-19 among Clinical Healthcare Workers in Bingham University Teaching Hospital (BHUTH) Jos, Plateau State, Nigeria

BACKGROUND

The ongoing Covid-19 pandemic is now a global health emergency with significant morbidity and mortality among different populations of the world. Healthcare professionals are the people in the front line of situations like this. Their perspectives on the pandemic is critical to their safety and the outcomes in patients they manage. The aim of this study is to assess the knowledge, attitude and practice regarding COVID-19 among clinical healthcare professionals in Bingham University Teaching Hospital (BHUTH) Jos.

MATERIALS AND METHODS

A total of 138 clinical health workers from BHUTH completed a questionnaire- based study on the knowledge, attitude and practice on COVID-19 from the April 1st to 30th May 2020. Consecutive sampling method was used for data collection and the distribution of responses was presented as frequencies and percentages. Analysis of Variance (ANOVA) test was used to investigate the level of association among variables at the significance level of p<0.05.

RESULTS

The highest mean of correct responses for knowledge were from doctors, pharmacists and nurses with 19.1±2.35, 19.4±1.52 and 18.9±1.73 respectively. The lowest mean was from pharmacist assistant and nurse aids with 17.1±1.81. The difference was statistically significant with Anaysis of Variance (F) of 5.75 and p value of 0.001. The attitude and practice mean were good between the different clinical cadre; however, the difference was not significant.

CONCLUSION

There is good knowledge, attitude and practice among the doctors and pharmacists, nurses, nurse assistants and pharmacist assistants. The doctors and pharmacist had better scores. There is the need for regular training and update.

Estimating the magnitude of pulmonary tuberculosis patients missed by primary health care clinics in South Africa

SETTING

The present study was conducted at 20 randomly selected primary health clinics across Buffalo City Metropolitan Health District, a high TB burden district in South Africa.

OBJECTIVE

To estimate the proportion of TB patients missed by primary health clinics.

DESIGN

We enrolled 1255 TB-symptomatic individuals exiting primary health clinics between March and December 2015. Participants were interviewed and asked to provide sputum for Xpert® MTB/RIF testing.

RESULTS

Clinic staff screened 79.1% of participants seeking care for TB-related symptoms and 21.9% of those attending a clinic for other reasons (P < 0.001). Of those screened by clinic staff, 21.5% reported submitting sputum, although only 9.8% had available results. Study staff tested sputum from 779 participants not tested by clinic staff. Of these, 39 (5.0%) individuals tested positive for TB, three of whom were rifampicin-resistant; 15/39 (38.5%) were never screened and 24/39 (61.5%) were screened but not tested by clinic staff. We estimate that the health system missed 62.9-78.5% of TB patients attending primary health clinics for TB-related symptoms and 89.5-100% of those attending a clinic for other reasons.

CONCLUSION

Low rates of TB screening and testing by the health system resulted in missed TB patients. Universal TB screening and testing of symptomatic individuals should be instituted in high TB burden communities in South Africa.

Surgical techniques for pelvic floor reconstruction: review of the recent literature

The number of women who will undergo pelvic organ prolapse repair is predicted to increase by almost 50% by 2050. Surgeons need updated knowledge and mastery of pelvic floor reconstruction in order to meet the rising demand for services. This review provides an update on the evidence for the various surgical techniques for anterior, posterior, and apical pelvic organ prolapse, specifically focusing on randomized trials within the last ten years.

Impaired event memory and recollection in a case of developmental amnesia

A current debate in the literature is whether all declarative memories and associated memory processes rely on the same neural substrate. Here, we show that H.C., a developmental amnesic person with selective bilateral hippocampal volume loss, has a mild deficit in personal episodic memory, and a more pronounced deficit in public event memory; semantic memory for personal and general knowledge was unimpaired. This was accompanied by a subtle difference in impairment between recollection and familiarity on lab-based tests of recognition memory. Strikingly, H.C.'s recognition did not benefit from a levels-of-processing manipulation. Thus, not all types of declarative memory and related processes can exist independently of the hippocampus even if it is damaged early in life.

Glucose stimulates human beta cell replication in vivo in islets transplanted into NOD-severe combined immunodeficiency (SCID) mice

AIMS/HYPOTHESIS

We determined whether hyperglycaemia stimulates human beta cell replication in vivo in an islet transplant model

METHODS

Human islets were transplanted into streptozotocin-induced diabetic NOD-severe combined immunodeficiency mice. Blood glucose was measured serially during a 2 week graft revascularisation period. Engrafted mice were then catheterised in the femoral artery and vein, and infused intravenously with BrdU for 4 days to label replicating beta cells. Mice with restored normoglycaemia were co-infused with either 0.9% (wt/vol.) saline or 50% (wt/vol.) glucose to generate glycaemic differences among grafts from the same donors. During infusions, blood glucose was measured daily. After infusion, human beta cell replication and apoptosis were measured in graft sections using immunofluorescence for insulin, and BrdU or TUNEL.

RESULTS

Human islet grafts corrected diabetes in the majority of cases. Among grafts from the same donor, human beta cell proliferation doubled in those exposed to higher glucose relative to lower glucose. Across the entire cohort of grafts, higher blood glucose was strongly correlated with increased beta cell replication. Beta cell replication rates were unrelated to circulating human insulin levels or donor age, but tended to correlate with donor BMI. Beta cell TUNEL reactivity was not measurably increased in grafts exposed to elevated blood glucose.

CONCLUSIONS/INTERPRETATION

Glucose is a mitogenic stimulus for transplanted human beta cells in vivo. Investigating the underlying pathways may point to mechanisms capable of expanding human beta cell mass in vivo.

The murine double-stranded RNA-dependent protein kinase PKR is required for resistance to vesicular stomatitis virus

Interferon (IFN)-induced antiviral responses are mediated through a variety of proteins, including the double-stranded RNA-dependent protein kinase PKR. Here we show that fibroblasts derived from PKR(-/-) mice are more permissive for vesicular stomatitis virus (VSV) infection than are wild-type fibroblasts and demonstrate a deficiency in alpha/beta-IFN-mediated protection. We further show that mice lacking PKR are extremely susceptible to intranasal VSV infection, succumbing within days after instillation with as few as 50 infectious viral particles. Again, alpha/beta-IFN was unable to rescue PKR(-/-) mice from VSV infection. Surprisingly, intranasally infected PKR(-/-) mice died not from pathology of the central nervous system but rather from acute infection of the respiratory tract, demonstrating high virus titers in the lungs compared to similarly infected wild-type animals. These results confirm the role of PKR as the major component of IFN-mediated resistance to VSV infection. Since previous reports have shown PKR to be nonessential for survival in animals challenged with encephalomyocarditis virus, influenza virus, and vaccinia virus (N. Abraham et al., J. Biol. Chem. 274:5953-5962, 1999; Y. Yang et al., EMBO J. 14:6095-6106, 1995), our findings serve to highlight the premise that host dependence on the various mediators of IFN-induced antiviral defenses is pathogen specific.

Prospective study of biliary strictures to determine the predictors of malignancy

BACKGROUND

There have been few prospective studies regarding the investigation of biliary strictures, principally because of rapid technological change. The present study was designed to determine the sensitivity of various imaging studies for the detection of biliary strictures. Serum biochemistry and imaging studies were evaluated for their role in distinguishing benign from malignant strictures.

METHODS

Thirty-one patients with suspected noncalculus biliary obstruction were enrolled consecutively in the study. A complete biochemical profile, ultrasound, Disida scan and cholangiogram (endoscopic retrograde cholangiopancreatography [ERCP] or percutaneous cholangiogram) were obtained at study entry. Stricture etiology was determined based on cytology, biopsy and/or clinical follow-up at one year.

RESULTS

Twenty-nine of 31 patients had biliary strictures, of which 15 were malignant. The mean age of the malignant cohort was 73.9 years versus 53.9 years in the benign cohort (P<0.001). Statistically significant differences between the malignant and benign groups, respectively, were as follows: alanine transaminase 235.2 versus 66.9 U/L (P=0.004), aspartate transaminase 189.8 versus 84.5 U/L (P=0.011), alkaline phosphatase 840.2 versus 361.1 U/L (P=0.002), bilirubin 317.8 versus 22.1 micromol/L (P<0. 001) and bile acids 242.5 versus 73.2 micromol/L (P=0.001). Threshold analysis using receiver operative characteristic (ROC) curves demonstrated that a bilirubin level of 75 micromol/L was most predictive of malignant strictures. Intrahepatic duct dilation was present in 93% of malignant strictures versus 36% of benign strictures (P=0.002). Common hepatic duct dilation was less discriminatory (malignant 13.5 versus benign 9.6 mm; P=0.11). Ultrasound was highly sensitive (93%) in the detection of the primary tumour in the bile duct or pancreas, or in the visualization of nodal or liver metastases. In benign disease, ultrasound failed to detect evidence of intrahepatic or extrahepatic biliary dilation in most cases. Disida scans were not able to distinguish between malignant or benign strictures and could not accurately localize the level of obstruction. The sensitivity of Disida scan for the diagnosis of obstruction was 50%. Cholangiographic characterization of strictures revealed an equal distribution of smooth (eight of 13) and irregular (five of 13) strictures in the malignant group. Ten of 13 benign strictures were characterized as smooth. Malignant strictures were significantly longer than benign ones - 30.3 versus 9.2 mm (P=0.001). Threshold analysis using ROC curves showed that strictures greater than or equal to 14 mm were predictive of malignancy (sensitivity 78%, specificity 75%, log odds ratio 11.23).

CONCLUSIONS

A serum bilirubin level of 75 micromol/L or higher, or a stricture length of greater than 14 mm was highly predictive of malignancy in patients with a biliary stricture. Ultrasound was useful in predicting malignant strictures by detecting either intrahepatic duct dilation or by visualizing the tumour (primary or metastases). Strictures with a 'benign' cholangiographic appearance are frequently malignant. Disida scan did not add additional information. ERCP is necessary to diagnose benign strictures, which tend to be less extensive at presentation.

Double-stranded-RNA-activated protein kinase PKR enhances transcriptional activation by tumor suppressor p53

The tumor suppressor p53 plays a key role in inducing G1 arrest and apoptosis following DNA damage. The double-stranded-RNA-activated protein PKR is a serine/threonine interferon (IFN)-inducible kinase which plays an important role in regulation of gene expression at both transcriptional and translational levels. Since a cross talk between IFN-inducible proteins and p53 had already been established, we investigated whether and how p53 function was modulated by PKR. We analyzed p53 function in several cell lines derived from PKR+/+ and PKR-/- mouse embryonic fibroblasts (MEFs) after transfection with the temperature-sensitive (ts) mutant of mouse p53 [p53(Val135)]. Here we report that transactivation of transcription by p53 and G0/G1 arrest were impaired in PKR-/- cells upon conditions that ts p53 acquired a wild-type conformation. Phosphorylation of mouse p53 on Ser18 was defective in PKR-/- cells, consistent with an impaired transcriptional induction of the p53-inducible genes encoding p21(WAF/Cip1) and Mdm2. In addition, Ser18 phosphorylation and transcriptional activation by mouse p53 were diminished in PKR-/- cells after DNA damage induced by the anticancer drug adriamycin or gamma radiation but not by UV radiation. Furthermore, the specific phosphatidylinositol-3 (PI-3) kinase inhibitor LY294002 inhibited the induction of phosphorylation of Ser18 of p53 by adriamycin to a higher degree in PKR+/+ cells than in PKR-/- cells. These novel findings suggest that PKR enhances p53 transcriptional function and implicate PKR in cell signaling elicited by a specific type of DNA damage that leads to p53 phosphorylation, possibly through a PI-3 kinase pathway.

Characterization of transgenic mice with targeted disruption of the catalytic domain of the double-stranded RNA-dependent protein kinase, PKR

The interferon-inducible, double-stranded RNA-dependent protein kinase PKR has been implicated in anti-viral, anti-tumor, and apoptotic responses. Others have attempted to examine the requirement of PKR in these roles by targeted disruption at the amino terminal-encoding region of the Pkr gene. By using a strategy that aims at disruption of the catalytic domain of PKR, we have generated mice that are genetically ablated for functional PKR. Similar to the other mouse model of Pkr disruption, we have observed no consequences of loss of PKR on tumor suppression. Anti-viral response to influenza and vaccinia also appeared to be normal in mice and in cells lacking PKR. Cytokine signaling in the type I interferon pathway is normal but may be compromised in the erythropoietin pathway in erythroid bone marrow precursors. Contrary to the amino-terminal targeted Pkr mouse, tumor necrosis factor alpha-induced apoptosis and the anti-viral apoptosis response to influenza is not impaired in catalytic domain-targeted Pkr-null cells. The observation of intact eukaryotic initiation factor-2alpha phosphorylation in these Pkr-null cells provides proof of rescue by another eukaryotic initiation factor-2alpha kinase(s).

The murine PKR tumor suppressor gene is rearranged in a lymphocytic leukemia

The double-stranded RNA-dependent kinase, PKR, is encoded by an interferon inducible gene and is largely responsible for the anti-viral effects of this cytokine. Recent studies have shown that PKR may also play a role in the regulation of normal cellular growth. Although numerous examples of viral strategies for inactivation of PKR exist, there is no evidence of PKR inactivation in tumors. We demonstrate here that the Tik gene, which encodes a dual-specificity kinase, is the murine homolog of PKR, the dsRNA-dependent kinase, and has undergone a rearrangement of one allele in a murine lymphocytic leukemia cell. We have cloned a cDNA that corresponds to a mutated transcript from the rearranged mPKR gene and show that while the mutated polypeptide retains its ability to dimerize and bind dsRNA, it is catalytically inactive. Although this mutated mPKR lacks apparent dominant-negative function, the net effect of reduced PKR activity in these cells may be significant.

Open versus closed surgical treatment of abscesses: a controlled clinical trial

BACKGROUND

Conventional drainage, curettage and packing of acute superficial abscesses has been challenged and in some centres replaced by curettage and primary closure under antibiotic cover. This technique has not been used widely in Australasia or North America, probably because of the lack of reassurance from local randomized trials.

METHODS

A randomized trial was conducted to compare the primary closure of acute superficial abscesses to conventional packing. Abscesses requiring drainage under a general anaesthetic were considered for the study, excluding extensive, secondary and deep suppurations. In the 'open' group, the abscess was drained, curetted, irrigated, and then packed. Instead of packing, the cavity in the 'closed' group was obliterated using interrupted vertical mattress skin sutures with/without closed suction drainage. Other aspects of management were standardized.

RESULTS

Of the 32 abscesses treated using the closed technique, 25 (78%) healed by primary intention after 1 week (SE(p) = 7.3%; 95% CI = 63.7-92.4%). One of the 29 abscesses (3%) treated using the open technique healed by secondary intention in a similar period of time. The difference was statistically significant (Chi-squared test with Yates' continuity correction = 31.70; P < 0.0001). There was no statistically significant difference in the overall incidence of healing, 1 month after surgery (chi 1(2) = 0.07; P > 0.9). In the closed group, healing was obtained by primary intention, leaving a linear surgical scar in 84% of the cases (SE(p) = 5.7%; 95% CI = 72.8-95.2%). Hospitalization and the need for analgesia and dressing changes were reduced by 40-60%.

CONCLUSIONS

Primary closure of acute superficial abscesses was associated with an improved outcome in terms of duration and quality of healing, postoperative pain, length of hospitalization, nursing care and, by implication, cost, and may be recommended as an alternative treatment that is superior to the orthodox technique.

Morphologic characteristics of erythroleukemia (acute myeloid leukemia; FAB-M6): a CALGB study

We have reviewed the clinical, morphologic, immunophenotypic, and cytogenetic features of 52 patients with erythroleukemia (FAB Cooperative Group; AML-M6) studied by the Cancer and Leukemia Group B (CALGB). The purpose of this study was to correlate morphology with the clinical features, immunophenotypes, and karyotypes of neoplastic cells, and with the response to therapy of patients with AML-M6. Thirty-three patients (63%) were male, median age 59 (range 16-81) years, 47 patients (90%) were white, and 42 patients (81%) had a performance status of < 2. Myelodysplastic changes were observed in at least 1 cell lineage in all cases, and in 2 cell lineages in 45 of 52 (86%) cases. Fifty percent or more of cases studied were positive for CD11b, CD13, CD15, CD33, glycophorin-A, and HLA-DR markers. Fourteen of 27 cases (52%) in whom karyotypic analyses were conducted had cytogenetic abnormalities. Five (19%) were simple (< 3 karyotypic abnormalities), while 9 (33%) were complex (> or = 3 abnormalities). We observed either a complete or partial loss of chromosomes 5, 7, or 12p, or the presence of trisomy 8, in 11 of 27 (41%) patients. Cases of AML-M6 were divided into group 1 (14 patients with bone marrow proerythroblasts and basophilic erythroblasts > 25% of all erythroblasts) and group 2 (38 patients with proerythroblasts and basophilic erythroblasts < or = 25% of all erythroblasts). We observed no significant differences between groups 1 and 2 in regard to sex, age, race, performance status, percentage of blood erythroblasts or myeloblasts, percentage of bone marrow erythroblasts, and periodic acid-Schiff (PAS) or myelodysplasia scores. Six of 6 (100%) patients of group 1, and 7 of 21 (33%) patients of group 2, had normal karyotypes (P = .006). Nine of 13 (69%) patients of group 1 and 15 of 33 (45%) patients of group 2 had a complete remission (CR) (P = .2). Eight of 11 (73%) cytogenetically normal patients achieved CR: 5 of 6 (83%) in group 1, and 3 of 5 (60%) in group 2. Five of 12 (42%) cytogenetically abnormal patients achieved CR. No difference in duration of survival (group 1, median = 4.6 months vs. group 2, median = 10.2 months; P = .93) was observed between the 2 groups. We conclude that AML-M6 is typified by multilineage involvement of hematopoietic cells. The morphology of erythroblasts in patients with AML-M6 may correlate with cytogenetic abnormalities and rate of CR.

Dual specificity kinases--a new family of signal transducers

Phosphorylation/dephosphorylation reactions are one of the dynamic mechanisms through which cells modulate protein activity in response to environmental stimuli. The eukaryotic molecules which are responsible for the phosphorylation of serine, threonine and tyrosine residues appear to have co-ordinately evolved from simple prokaryotic enzymes which primarily respond to nutritional cues. In multicellular eukaryotes the complexity of data transfer greatly exceeds that of simple bacteria. The eukaryotic cell needs to exchange information with neighbouring and distant sister cells. Positional, nutritional and hormonal data are transmitted from the extracellular milieu across the plasma membrane and into the cytoplasm. In certain cases the signal must pass into the nucleus or other subcellular organelles where it is decoded and the proper cellular response initiated. All of these events have been shown to have a protein kinase component and it seems likely that in mammalian cells over 1,000 different kinase molecules have evolved to form the requisite signal transducing networks. In this review we describe a previously unappreciated family of protein kinases, the dual specificity or DSK kinases, which play important roles in the regulation of normal cellular growth and differentiation.

Use of self-administered joint counts in the evaluation of rheumatoid arthritis patients

The validity and reliability of self-administered joint counts are reported in a group of 32 rheumatoid arthritis patients being followed at a university-based practice located in the Southeast region of the United States, serving low to middle income urban and rural patients. Adequate inter-rater reliability among the patients' and the research assistant's joint counts was obtained for upper (r = 0.74), lower (r = 0.96), and upper and lower extremities (r = 0.89). Convergent validity correlations for pain, helplessness, and the Joint Alignment and Motion scale were found to be adequate. We conclude that rheumatoid arthritis patients can reliably assess their joint counts. Self joint counts along with other validated self-reports of health status may be applicable to busy outpatient settings, as well as in clinical research.

Sequential addition of deferoxamine and hemin inhibits glioma tumor-cell growth

The toxicity of deferoxamine, a potent iron chelator may be antagonized by hemin a potential iron source. Using the MTT assay we explored the effects of different concentrations and schedules of deferoxamine and hemin or deferoxamine and iron free tin protoporphyrin (SnPP) in two neuroblastoma (VA-N-BR, SK-N-AS), and two glioblastoma multiforme (VA-MG-SL, and U-373 MG) cell lines. In these cell lines, survival after exposure to 10 mug/ml deferoxamine for three days ranged from 28% to 59%. Incubation with hemin alone, had variable effects on growth depending on the cell line. Concomitant exposure to equimolar concentrations of deferoxamine and hemin resulted in the reversal of deferoxamine induced toxicity. Surprisingly, in the glioblastoma multiforme cell lines sequential exposure to deferoxamine and then hemin resulted in additional toxic effects rather than abrogation of deferoxamine toxicity. Sequential exposure of all cell lines to deferoxamine, hemin, and the chemotherapeutic agent thiotepa resulted in enhanced toxicity over any drug used alone. Exposure of the cells to deferoxamine and SnPP or deferoxamine and FeCl3 did not result in increased toxicity. These results implicate iron as the toxic element but indicate that the iron is only toxic when presented to the cell bound to protoporphyrin, such as found in hemin.

Structural requirements for enhancement of T-cell responsiveness by the lymphocyte-specific tyrosine protein kinase p56lck

To understand the mechanism(s) by which p56lck participates in T-cell receptor (TCR) signalling, we have examined the effects of mutations in known regulatory domains of p56lck on the ability of F505 p56lck to enhance the responsiveness of an antigen-specific murine T-cell hybridoma. A mutation of the amino-terminal site of myristylation (glycine 2), which prevents stable association of p56lck with the plasma membrane, completely abolished the ability of F505 p56lck to enhance TCR-induced tyrosine protein phosphorylation. Alteration of the major site of in vitro autophosphorylation, tyrosine 394, to phenylalanine diminished the enhancement of TCR-induced tyrosine protein phosphorylation by F505 p56lck. Such a finding is consistent with the previous demonstration that this site is required for full activation of p56lck by mutation of tyrosine 505. Strikingly, deletion of the noncatalytic Src homology domain 2, but not of the Src homology domain 3, markedly reduced the improvement of TCR-induced tyrosine protein phosphorylation by F505 Lck. Additional studies revealed that all the mutations tested, including deletion of the Src homology 3 region, abrogated the enhancement of antigen-triggered interleukin-2 production by F505 p56lck, thus implying more stringent requirements for augmentation of antigen responsiveness by F505 Lck. Finally, it was also observed that expression of F505 p56lck greatly increased TCR-induced tyrosine phosphorylation of phospholipase C-gamma 1, raising the possibility that phospholipase C-gamma 1 may be a substrate for p56lck in T lymphocytes. Our results indicate that p56lck regulates T-cell antigen receptor signalling through a complex process requiring multiple distinct structural domains of the protein.

A comparison of the full and short versions of the Arthritis Impact Measurement Scales

This study examined the validity and reliability of full and short versions of the Arthritis Impact Measurement Scales (AIMS). One hundred fifty-five patients with Rheumatoid Arthritis followed at a University Hospital Rheumatology Clinic completed the full AIMS at baseline, 6 months, 12 months, and 18 months. After reducing the 45-item AIMS to 22, alpha reliabilities and test-retest correlations showed that, with the exception of test-retest correlations for mobility at 6 months and for pain at 12 and 18 months, the full and short scales were comparably reliable. Convergent validity correlations with theoretically related scales were also comparable. However, some of the short scales did not detect the same differences over time that the full scales did. Specifically, the short mobility, pain, anxiety, and depression scales were not as sensitive to change as the full scales. Except for these four scales, the short version appears to be a viable alternative for use by health professionals and researchers.

[Notes on the phantom. Supplements to Freud's metapsychology]

The author discusses secrets--phantoms--that are unconsciously passed on within a family from one generation to the next. They are experienced as foreign bodies and are not physically processed. A special technique is needed to decode them in the analytic process.

Disease and psychosocial factors related to physical functioning in rheumatoid arthritis

One hundred and fifty-five patients with rheumatoid arthritis (RA) were randomly selected from a tertiary care outpatient rheumatology clinic. Disease, treatment, psychosocial and demographic data were collected to test a biopsychosocial model of Physical Functioning as determined by the Arthritis Impact Measurement Scales (AIMS). Cross-sectional and longitudinal hierarchical and stepwise regression analysis were performed to identify variables associated with Physical Functioning. The results of the hierarchical regression revealed that only the disease and psychosocial sets of variables were significant. Stepwise regression revealed that Disease Severity (disease set) and Arthritis Helplessness (psychosocial set) accounted for 37% (longitudinal) to 60% (cross-sectional 12 months---greater than 12 months) of Physical Functioning variance. Our results suggest a role for the inclusion of psychosocial factors in studies of the development of physical disability in patients with RA.

Tyrosine phosphorylation of GAP and GAP-associated proteins in lymphoid and fibroblast cells expressing lck

The Ras GTPase activating protein (GAP) is a strong candidate for the protein that links protein-tyrosine kinases to the Ras mitogenic pathway. GAP and two associated proteins, p62 and p190, were shown to be phosphorylated on tyrosine in the LSTRA thymoma cell line, in which the p56lck tyrosine kinase is overexpressed as a result of retroviral promoter insertion. In NIH3T3 fibroblasts expressing specific oncogenic and transformation-defective variants of p56lck, we found that the tyrosine phosphorylation of GAP complexes required both enzymatic activation and myristylation of p56lck, and correlated with lck transforming activity. The interaction between p62 and p190 from lck-transformed fibroblasts and GAP could be reconstituted in vitro using bacterial TrpE fusion proteins containing GAP Src homology 2 (SH2) domains. In vitro complex formation was insensitive to the prior denaturation of SH2 ligands, suggesting that SH2-binding sites are formed by linear peptide sequences. These results suggest that the tyrosine phosphorylation of GAP, and its interactions with SH2-binding proteins, may be involved in fibroblast transformation by activated lck, and may participate in signal transduction and cellular transformation in lymphoid cells.

The lymphocyte-specific tyrosine protein kinase p56lck

The CD4 and CD8 T cell surface antigens are physically associated with the tyrosine protein kinase p56lck. Accumulating data indicate that p56lck transduces intracellular tyrosine protein phosphorylation signals upon engagement of CD4 and CD8 by major histocompatibility complex (MHC) determinants expressed on antigen-presenting cells (APCs). Recent studies show that these p56lck-related phosphorylation events enhance T cell receptor (TCR)-mediated functions and are critical for the proposed co-receptor roles of CD4 and CD8. p56lck is also capable of enhancing antigen receptor responsiveness in the absence of CD4 or CD8 expression, suggesting that it can directly contribute to the TCR-induced tyrosine phosphorylation signal.

Enhancement of T-cell responsiveness by the lymphocyte-specific tyrosine protein kinase p56lck

Lymphocyte-specific tyrosine protein kinase p56lck is physically associated with CD4 and CD8 T-cell surface molecules, suggesting that it may transduce CD4/CD8-triggered tyrosine phosphorylation signals during antigen stimulation. Indeed, antibody-mediated aggregation of CD4 (to mimic interaction with its ligand, major histocompatibility complex (MHC) class II molecules), rapidly elevates the kinase activity of p56lck and is associated with marked changes in tyrosine protein phosphorylation. Genetic analyses suggest that the interaction of CD4/CD8 with p56lck results in a positive signal during antigen-induced T-cell activation. To evaluate directly the role of p56lck in T-cell activation, we introduced a constitutively activated form of Lck protein (tyrosine 505 to phenylalanine 505 mutant); in a CD4-negative, MHC-class II restricted mouse T-cell hybridoma. We report here that, as for transfection of CD4, expression of the Lck mutant enhanced T-lymphocyte responsiveness. This finding provides direct evidence that p56lck can positively regulate T-cell functions and that it mediates at least some of the effects of CD4 and CD8 on T-cell activation.

Activation of p56lck through mutation of a regulatory carboxy-terminal tyrosine residue requires intact sites of autophosphorylation and myristylation

Mutation of the major site of in vivo tyrosine phosphorylation of p56lck (tyrosine 505) to a phenylalanine constitutively enhances the p56lck-associated tyrosine-specific protein kinase activity. The mutant polypeptide is extensively phosphorylated in vivo at the site of in vitro Lck autophosphorylation (tyrosine 394) and is capable of oncogenic transformation of rodent fibroblasts. These observations have suggested that phosphorylation at Tyr-505 down regulates the tyrosine protein kinase activity of p56lck. Herein we have attempted to examine whether other posttranslational modifications may be involved in regulation of the enzymatic function of p56lck. The results indicated that activation of p56lck by mutation of Tyr-505 was prevented by a tyrosine-to-phenylalanine substitution at position 394. Furthermore, activation of p56lck by mutation of the carboxy-terminal tyrosine residue was rendered less efficient by substituting an alanine residue for the amino-terminal glycine. This second mutation prevented p56lck myristylation and stable membrane association and was associated with decreased in vivo phosphorylation at Tyr-394. Taken together, these findings imply that lack of phosphorylation at Tyr-505 may be insufficient for enhancement of the p56lck-associated tyrosine protein kinase activity. Our data suggest that activation of p56lck may be dependent on phosphorylation at Tyr-394 and that this process may be facilitated by myristylation, membrane association, or both.

A comprehensive approach to teaching management in a degree-completion dental hygiene program

Changes in society have dictated changes in the future of the dental hygiene profession and in the curriculum used to prepare students. Dental hygiene students should be prepared to assume a variety of new roles in the oral health and health care fields, including administrator/manager, researcher, educator, clinician, patient advocate, and change agent. The role of the administrator/manager had been identified as an important one for dental hygienists. In order to develop the skills necessary to obtain a position in management or administration, dental hygiene students should have educational preparation in these areas. This paper describes the development of an enhanced business curriculum in a degree-completion program. The curriculum provides a basic foundation for the development of effective management skills and includes courses in business, human resources management, and marketing, along with elective course offerings and an externship program. An integrated approach to management is employed, with emphasis on application to oral health and health care delivery systems.

Prolonged apnoea with severe arterial hypoxaemia resulting from complex partial seizures

Multi-channel tape-recordings of the EEG, breathing movements, arterial pulsed oxygen saturation and ECG were performed on a four-year-old child with a history of cyanotic episodes. These had started at nine months of age, resulted in cardiopulmonary resuscitation on unnumerable occasions, and were refractory to anti-epileptic medication. During each episode seizure activity appeared first, followed within a few seconds by sinus tachycardia, prolonged absence of inspiratory efforts and severe arterial hypoxaemia. As the seizure activity ended, breathing movements restarted and there was a gradual improvement in oxygenation.