Erratum: A novel probe for measuring tissue bioelectrical impedance to enhance pedicle screw placement in spinal surgery

[This corrects the article on p. 2205 in vol. 10, PMID: 30093957.].

Outcomes of respiratory viral-bacterial co-infection in adult hospitalized patients

BACKGROUND

Viral infections of the respiratory tract represent a major global health concern. Co-infection with bacteria may contribute to severe disease and increased mortality in patients. Nevertheless, viral-bacterial co-infection patterns and their clinical outcomes have not been well characterized to date. This study aimed to evaluate the clinical features and outcomes of patients with viral-bacterial respiratory tract co-infections.

METHODS

We included 19,361 patients with respiratory infection due to respiratory viruses [influenza A and B, respiratory syncytial virus (RSV), parainfluenza] and/or bacteria in four tertiary hospitals in Hong Kong from 2013 to 2017 using a large territory-wide healthcare database. All microbiological tests were conducted within 48 h of hospital admission. Four etiological groups were included: (1) viral infection alone; (2) bacterial infection alone; (3) laboratory-confirmed viral-bacterial co-infection and (4) clinically suspected viral-bacterial co-infection who were tested positive for respiratory virus and negative for bacteria but had received at least four days of antibiotics. Clinical features and outcomes were recorded for laboratory-confirmed viral-bacterial co-infection patients compared to other three groups as control. The primary outcome was 30-day mortality. Secondary outcomes were intensive care unit (ICU) admission and length of hospital stay. Propensity score matching estimated by binary logistic regression was used to adjust for the potential bias that may affect the association between outcomes and covariates.

FINDINGS

Among 15,906 patients with respiratory viral infection, there were 8451 (53.1%) clinically suspected and 1,087 (6.8%) laboratory-confirmed viral-bacterial co-infection. Among all the bacterial species, Haemophilus influenzae (226/1,087, 20.8%), Pseudomonas aeruginosa (180/1087, 16.6%) and Streptococcus pneumoniae (123/1087, 11.3%) were the three most common bacterial pathogens in the laboratory-confirmed co-infection group. Respiratory viruses co-infected with non-pneumococcal streptococci or methicillin-resistant Staphylococcus aureus was associated with the highest death rate [9/30 (30%) and 13/48 (27.1%), respectively] in this cohort. Compared with other infection groups, patients with laboratory-confirmed co-infection had higher ICU admission rate (p < 0.001) and mortality rate at 30 days (p = 0.028), and these results persisted after adjustment for potential confounders using propensity score matching. Furthermore, patients with laboratory-confirmed co-infection had significantly higher mortality compared to patients with bacterial infection alone.

INTERPRETATION

In our cohort, bacterial co-infection is common in hospitalized patients with viral respiratory tract infection and is associated with higher ICU admission rate and mortality. Therefore, active surveillance for bacterial co-infection and early antibiotic treatment may be required to improve outcomes in patients with respiratory viral infection.

Is convention hip precaution necessary after total hip arthroplasty?

Background:

Dislocation is one of the most common causes of revision after total hip arthroplasty (THA). Standard hip precautions are thought to enhance soft-tissue healing and reduce dislocations. However, lifestyle restrictions affect a patient’s rehabilitation, quality of life (QOL), and satisfactions. We aim to compare conventional (CP) and minimal hip precautions (MP) after THA.

Methods:

Retrospective review of prospectively collected data in posterolateral approach THA. Chief surgeon assigns patients to CP or MP group. CP group had to sleep supine, used elevated toilet seats and chairs, avoid hip flexion greater than 90°, and no internal rotation or adduction for 6 weeks. MP group had no restrictions in hip movements, except for the combined flexion, adduction and internal rotation. All had a minimum 1-year follow-up. The number of dislocations, length of stay (LOS), time to independent toileting, Harris Hip Scores, QOL, and health perceptions, assessed by EuroQol 5D-5L, was compared between CP and MP groups.

Results:

Fifty-five THAs were included. CP group consisted of 17 primary and 12 revision THAs; MP group consisted of 21 primary and 5 revision THAs. There were two dislocations and both are revisions in CP group. Overall rate of dislocation was 6.9% in CP group and no dislocation in MP group (p-value > 0.05). MP group had shorter LOS (12 vs 19 days, p-value 0.04), higher EQ5D-5L health perception scores at 1-year (81.7 vs 70.9, p-value 0.01).

Conclusion:

MP group had shorter LOS and better health perceptions 1-year after THA with no increase in dislocation rates.

Emerging roles of long non-coding RNAs in osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) is a potentially disabling orthopedic condition that, in most late-stage cases, requires total hip arthroplasty. Although direct trauma to the hip (e.g. femoral neck fracture, hip dislocation) that leads to vascular interruption is a strong risk factor for ONFH, there are many non-traumatic risk factors (e.g. use of corticosteroid, alcohol abuse) which molecular mechanisms in ONFH still remain obscured. Long non-coding RNAs (lncRNAs) is a class of regulatory RNAs that play crucial roles in various cellular functions, including cell proliferation, invasion, metabolism, apoptosis and stem cell differentiation. Recent studies also suggested their participation in bone development and regeneration, and a direct involvement in the pathogenesis of numerous of orthopaedic conditions, such as ONFH. LncRNAs are differentially expressed in ONFH tissues as well as bone marrow-mesenchymal stem cells and bone microvascular endothelial cells isolated from ONFH patients. Functional studies further established their critical roles in regulating biological processes, such as osteoblast survival and osteogenic differentiation of bone marrow-mesenchymal stem cells, which are closely related to ONFH. The current review aims at summarizing the recent advancement in this field and discussing the potential diagnostic, prognostic and therapeutic utilities of lncRNAs in the clinical management of ONFH.

Association between complications and death within 30 days after noncardiac surgery

BACKGROUND

Among adults undergoing contemporary noncardiac surgery, little is known about the frequency and timing of death and the associations between perioperative complications and mortality. We aimed to establish the frequency and timing of death and its association with perioperative complications.

METHODS

We conducted a prospective cohort study of patients aged 45 years and older who underwent inpatient noncardiac surgery at 28 centres in 14 countries. We monitored patients for complications until 30 days after surgery and determined the relation between these complications and 30-day mortality using a Cox proportional hazards model.

RESULTS

We included 40 004 patients. Of those, 715 patients (1.8%) died within 30 days of surgery. Five deaths (0.7%) occurred in the operating room, 500 deaths (69.9%) occurred after surgery during the index admission to hospital and 210 deaths (29.4%) occurred after discharge from the hospital. Eight complications were independently associated with 30-day mortality. The 3 complications with the largest attributable fractions (AF; i.e., potential proportion of deaths attributable to these complications) were major bleeding (6238 patients, 15.6%; adjusted hazard ratio [HR] 2.6, 95% confidence interval [CI] 2.2-3.1; AF 17.0%); myocardial injury after noncardiac surgery [MINS] (5191 patients, 13.0%; adjusted HR 2.2, 95% CI 1.9-2.6; AF 15.9%); and sepsis (1783 patients, 4.5%; adjusted HR 5.6, 95% CI 4.6-6.8; AF 12.0%).

INTERPRETATION

Among adults undergoing noncardiac surgery, 99.3% of deaths occurred after the procedure and 44.9% of deaths were associated with 3 complications: major bleeding, MINS and sepsis. Given these findings, focusing on the prevention, early identification and management of these 3 complications holds promise for reducing perioperative mortality. Study registration: ClinicalTrials.gov, no. NCT00512109.

A novel probe for measuring tissue bioelectrical impedance to enhance pedicle screw placement in spinal surgery

Posterior spinal reconstruction with rods and pedicle screws has been widely used to corrects coliosis and other forms of degenerative spinal deformities. However, insertion of pedicle screwsis often clinically challenging, particularlyin patients with severe deformity. Bioelectrical impedance analysis is a technique that exploits the electrical properties of biological organs and tissues to indicate their compositions. Bioelectrical impedance measurement is non-invasive, simple, with adequate repeatability, and at a relatively low cost. In our study, we designed a bioelectrical impedance pedicle probe and use it to determine the bioelectrical impedance values in vitro and in vivo of different tissues relevant to pedicle screw insertion. We measured the bioelectrical impedance of different tissues relevant to pedicle screw placement in vitro and in vivo and explored the use of a prototype bioelectrical impedance pedicle probein guiding pedicle screw placement during spine surgery in animals. These data suggested that this novel bioelectrical impedance pedicle probe may be a new technique that has potential to offer accurate and safe placement of pedicle screws in spine surgery.

MicroRNAs: new players in cataract

Cataract is the most common cause of blindness worldwide. Multiple factors such as aging, eye injury, diabetes mellitus, ultraviolet exposure, drug use and other ocular diseases are etiologically linked to cataractogenesis. Due to a rapid increase in aging population, age-related cataract has become the leading cause of blindness. Therefore, it is urgent to understand the molecular mechanism underlying cataractogenesis. MicroRNAs (miRNAs) are a group of endogenous, small noncoding RNAs that regulate gene expression at the post-translational level through binding with the 3'-untranslated regions of target mRNAs. Studies have shown that miRNAs play important roles in multiple cellular functions, including apoptosis, cell proliferation, senescence and stress response. Deregulated expression of miRNAs is also linked to the pathogenesis of many diseases, including ocular diseases. In our review, we focus on miRNAs that are involved in cataract development and discuss their potential applications as novel diagnostic markers and therapeutic targets.

Modulation of chemoresponsiveness to platinum-based agents by microRNAs in cancer

Ovarian cancer accounts for the highest mortality among all gynecologic cancers. Cytoreductive surgery followed by chemotherapy with a platinum-based agent (cisplatin or carboplatin) plus paclitaxel is the first-line option for treatment of epithelial ovarian cancer. However, primary or acquired resistance to platinum-based agents is a major clinical challenge. MicroRNAs are a group of small non-coding RNAs that regulate gene expression post-transcriptionally and may function as oncogenes or tumor-suppressor genes through extensive crosstalk with intracellular signaling pathways. Importantly, their dysregulation has been implicated in ovarian tumorigenesis. Pertinent to chemotherapy, increasing evidence has revealed that miRNAs can be directly linked to chemosensitivity to platinum-based agents in ovarian cancer. In this review, we summarize current evidence concerning the role of miRNAs in prediction and modulation of cellular responses to cisplatin and carboplatin in ovarian cancer.

BANCR: a cancer-related long non-coding RNA

Long non-coding RNAs (lncRNAs) are a group of non-protein-coding RNAs with more than 200 nucleotides in length. lncRNAs are involved in diverse biological processes, including development, cell proliferation and differentiation. Emerging evidences also suggest that lncRNAs may participate in cancer development by functioning as tumor suppressors and oncogenes. BRAF-activated non-coding RNA (BANCR) was first identified as an oncogene in melanoma. Later studies demonstrated that BANCR was frequently deregulated in human cancers, including lung cancer, gastric cancer, colorectal cancer, thyroid cancer and osteosarcoma. Nevertheless, the direction of deregulation was tissue-specific in which BANCR could as an oncogene or tumor-suppressor gene. In this review, we compile current evidences concerning the functional roles and molecular mechanisms of BANCR in tumor development.

Choice of ANesthesia for EndoVAScular Treatment of Acute Ischemic Stroke: Protocol for a randomized controlled (CANVAS) trial

Background

Observational studies indicate that the type of anesthesia, local or general, may be associated with the post-procedural neurological function in patients with acute ischemic stroke undergoing endovascular treatment. However, these results need further confirmation, and the causal relationship has not yet been established.

Methods

This is a randomized controlled equivalence trial. Permuted block randomization stratified by culprit vessels will be used. Six hundred and forty patients with acute ischemic stroke undergoing endovascular recanalization will be randomized one to one to receive either general anesthesia or local anesthesia. The primary endpoint is the modified Rankin scale at 90 days after endovascular treatment. The secondary endpoints are the peri-procedural mortality and morbidity.

Discussion

The study aims to determine the effects of anesthetic choice on neurological outcomes in patients with acute ischemic stroke undergoing intra-arterial recanalization. If the results are positive, the study will indicate that the type of anesthesia does not affect neurological outcome after endovascular treatment. Trial registration: ClinicalTrial.gov identifier: NCT02677415

PAQR3: a novel tumor suppressor gene

PAQR3, also known as RKTG (Raf kinase trapping to Golgi), is a member of the progestin and adipoQ receptor (PAQR) family. The role of PAQR3 as a tumor suppressor has recently been established in different types of human cancer in which PAQR3 exerts its biological function through negative regulation of the oncogenic Raf/MEK/ERK signaling. Multiple studies have found that PAQR3 downregulation frequently occurs in human cancers and is very often associated with tumor progression and shortened patients' survival. Moreover, restoring the expression of PAQR3 could induce apoptosis and inhibit proliferation and invasiveness of cancer cells. Downregulation of PAQR3 by oncogenic microRNAs has also been reported. In this review, we summarized current knowledge concerning the role of PAQR3 in tumor development. To our knowledge, this is the first review on the role of this novel tumor suppressor.

Intravenous magnesium sulphate for aneurysmal subarachnoid hemorrhage: an updated systemic review and meta-analysis

INTRODUCTION

Previous meta-analyses of magnesium sulphate infusion in the treatment of aneurysmal subarachnoid hemorrhage (SAH) have become outdated due to recently published clinical trials. Our aim was thus to perform an up-to-date systemic review and meta-analysis of published data on the use of magnesium sulphate infusion in aneurysmal SAH patients.

METHODS

A systemic review and meta-analysis of the literature was carried out on published randomized controlled clinical trials that investigated the efficacy of magnesium sulphate infusion in aneurysmal SAH patients. The results were analyzed with regard to delayed cerebral ischemia (DCI), delayed cerebral infarction, and favorable neurological outcomes at three and six months. The risks of bias were assessed using the Jadad criteria, with a Jadad score >3 indicating a lower such risk. Meta-analyses are presented in terms of relative risk (RR) with 95% confidence intervals (CIs).

RESULTS

Six eligible studies with 875 patients were reviewed. The pooled RR for DCI was 0.87 (95% CI, 0.36 to 2.09; P = 0.75). That for delayed cerebral infarction was 0.58 (95% CI, 0.35 to 0.97; P = 0.04), although this result did not persist if only randomized clinical trials with a lower risk of bias were included (RR 0.61, 95% CI, 0.31 to 1.22; P = 0.17). The pooled RR for a favorable outcome at three months was 1.14 (95% CI, 0.99 to 1.31; P = 0.07), and that for a favorable outcome at six months was 1.08 (95% CI, 0.94 to 1.24; P = 0.29).

CONCLUSIONS

The present findings do not lend support to a beneficial effect of magnesium sulphate infusion on delayed cerebral infarction. The reduction in DCI and improvement in the clinical outcomes of aneurysmal SAH patients following magnesium sulphate infusion observed in previous pilot studies are not confirmed, although a beneficial effect cannot be ruled out because of sample size limitation.

Structured preoperative patient education for patient-controlled analgesia

STUDY OBJECTIVE

To investigate the effectiveness of a structured preoperative education program in patients receiving patient-controlled analgesia (PCA).

DESIGN

Randomized controlled trial.

SETTING

University-affiliated hospital.

PATIENTS

60 ASA physical status I and II women undergoing major gynecologic surgery.

INTERVENTIONS

Patients were randomly allocated to receive either standard information given during routine preanesthetic assessment (n = 30) or additional structured preoperative education on the use of PCA (n = 30).

MEASUREMENTS

All patients received standard anesthesia and PCA was provided for postoperative analgesia. Patients were reviewed bid by an independent team of pain specialists and nurses. Patient satisfaction, severity of postoperative pain, nausea, dizziness, and morphine consumption were measured at discharge from recovery room, 24, and 48 hours after operation. Recovery characteristics of patients were also measured.

MAIN RESULTS

Pain scores and morphine consumption decreased over time (p < 0.01), but there was no significant difference between groups. The overall analgesic efficacy, side effects, and recovery times was not affected by the education program. Patient satisfaction in the education group was better than control during early recovery (p= 0.03), but there was no additional benefit in the remaining postoperative period.

CONCLUSIONS

Structured preoperative PCA education did not affect patient outcome. The early improvement in patient satisfaction was minimized by continued education and pain team supervision during the rest of the postoperative period.

Transcranial Doppler ultrasonography (TCD) in ventilated head injured patients: correlation with stable xenon-enhanced CT

Disturbance of cerebral vasomotor regulation has been shown to be associated with the severity of traumatic brain injury (TBI). The transient hyperaemic response (THR) test is a test of the pressure autoregulatory response in terms of cerebral blood flow velocity after a brief carotid artery compression. Correlating with the test of cerebral vascular reactivity (CVR) to carbon dioxide by means of passive hyperventilation suggested that the THR test is a simple clinical test for the assessment of cerebral haemodynamic status in head-injured patients.

Risk factors for citation errors in peer-reviewed nursing journals

BACKGROUND

Citation errors are common among nursing journals. But, there are no data regarding the factors that predispose to these errors.

OBJECTIVE

To determine the risk factors that predispose to citation error in peer-reviewed nursing journals.

METHODS

Five hundred and fifty references were selected randomly from articles published in eleven nursing journals for the year 1998. The incidences of major and minor citation errors were determined by comparing with the original articles. The relative odds of citation errors for the number of authors, collaborating institutions and the length of the reference list were calculated. The correlation between the scientific quality of the journal (by means of journal impact factor and immediacy index) and the incidence of citation error were also determined.

RESULTS

The incidence of citation errors is comparable to those reported previously. Long reference lists in articles written by a single author predicted strongly the occurrence of minor citation errors. Journals with a high impact factor and immediacy index tend to contain fewer minor mistakes. None of these factors affect the incidence of major errors.

CONCLUSION

Contributors to journals should be aware of the various risk factors for citation errors. Citation accuracy may be improved by modifying these factors.

Diagnostic strategies in young patients with ischemic stroke in Canada

BACKGROUND

A preliminary national survey of ischemic stroke in the young (15-45 years) undertaken by the Canadian Stroke Consortium indicated that in 44% of 356 patients, no cause was found.

OBJECTIVE

To determine the reason for this high incidence of diagnostic uncertainty in young patients with ischemic stroke.

METHODS

Neurologists in the ten Canadian stroke centers completed a detailed questionnaire for patients aged 15-45 years admitted to hospital between January 1993 and December 1997. Using a stepwise diagnostic algorithm incorporating clinical, neuroimaging, neurovascular and laboratory data, we divided patients into three groups: (1) those with established cause for the ischemic stroke, (2) those who remained unexplained despite adequate investigation, (3) those who remained unexplained but were, in our opinion, under-investigated.

RESULTS

In 197 patients (56%), an identified cause was established including cardioembolic sources (14%), extracranial arterial dissection (13%), lacunar infarcts (8%) atherosclerosis (6%). A miscellaneous group of 15%, included cerebral venous thrombosis, coagulopathies, vasculitis and others. In 159 patients (44%) with no apparent cause for their stroke, we considered only 81 (23%) adequately investigated, and 78 (21%) inadequately investigated.

CONCLUSION

About one in five young patients was inadequately investigated by a stroke-oriented group of neurologists. The major problem appears to be restriction of investigations to neuroimaging alone (usually computerized cerebral tomography), without further tests such as cerebral angiography and cardiac imaging.

Propofol requirement is decreased in patients with large supratentorial brain tumor

BACKGROUND

The anesthetic requirement is decreased in animals with head injury, but there are no data regarding the effect of intracranial tumor on the potency for intravenous anesthetics. The authors compared the quantal dose-response curves for propofol in patients having large (> or = 30 mm, mass effect) brain tumor with those having smaller (< 30 mm) lesions and with control patients undergoing noncranial surgery.

METHODS

Sixty patients in each group were randomly assigned to receive one of the six doses of propofol (0.5, 0.7, 1.0, 1.3, 1.8, or 2.5 mg/kg) over 10 s. Two minutes after drug administration, patients were asked to open their eyes as a test for response to verbal command. Patients who failed to respond were given a 10-s, 50-Hz, 80-mA transcutaneous tetanic electrical current to the ulnar nerve as a test for response to painful stimulus. Purposeful movement indicated positive response. Log dose-response curves for loss of response to verbal command and tetanic stimulus were calculated after logit transformation.

RESULTS

The median effective doses (ED50s; 95% confidence interval) for suppressing response to verbal command and tetanic stimulus were 0.75 (0.65-0.86) mg/kg and 1.28 (1.11-1.49) mg/kg, respectively, in patients with large brain tumor. These values were significantly less than the corresponding ED50s in patients with small tumor, 1.01 (0.88-1.15) mg/kg and 1.76 (1.51-2.07) mg/kg, or healthy control subjects, 0.98 (0.86-1.12) mg/kg and 1.89 (1.62-2.23) mg/kg.

CONCLUSIONS

The doses of propofol required to suppress response to verbal command and tetanic stimulus were 23% less and 32% less in patients with large brain tumor compared with control subjects. Small tumor did not affect potency of propofol.

Mechanisms of glucocorticoid reduction in asthmatic subjects treated with intravenous immunoglobulin

BACKGROUND

Intravenous immunoglobulin (IVIG) has been used as an oral glucocorticoid (GC)-sparing agent in patients with steroid-dependent asthma. Despite its use, little is known regarding its mechanism of action.

OBJECTIVE

We sought to determine whether the GC-sparing effects of IVIG in severe asthma are related to improved GC receptor (GCR)-binding affinity and subsequent enhanced GC sensitivity.

METHODS

In an open-label study, 11 steroid-dependent asthmatic subjects (6 GC-insensitive, 5 GC-sensitive) received monthly infusions of IVIG (2 g/kg) for 6 months. Peak expiratory flow rates and oral GC dose were recorded daily, and spirometry was performed monthly. Blood was drawn for lymphocyte stimulation assays and GCR assays at baseline and after 3 and 6 months of therapy. Lymphocytes were stimulated ex vivo with PHA in the presence and absence of IVIG and increasing concentrations of dexamethasone (DEX).

RESULTS

IVIG resulted in significant reductions in oral GC dose (P <.02), number of GC bursts (P =.033), and hospitalizations (P =.001) after 6 months of IVIG. Those with GC-insensitive asthma responded equally well to IVIG as those with GC-sensitive asthma. Associated with the improved clinical efficacy, IVIG acted synergistically with DEX in suppressing lymphocyte activation as measured by a shift in the DEX dose-response curve by 1 log-fold (P =.03). IVIG therapy was also associated with significantly improved GCR-binding affinity (P =.01).

CONCLUSIONS

IVIG resulted in significant reductions in oral GC requirements and hospitalizations in a group of patients with severe asthma, with IVIG being as effective in patients with GC-insensitive asthma as in patients with GC-sensitive asthma. IVIG therapy acted synergistically with DEX in suppressing lymphocyte activation and significantly improved GCR-binding affinity after 3 and 6 months of therapy.

Single-dose tropisetron for preventing postoperative nausea and vomiting after breast surgery

In this randomized, double-blind, placebo-controlled study, we compared the efficacy of tropisetron 5 mg with tropisetron 2 mg for the prevention of postoperative nausea and vomiting (PONV) after breast surgery. One hundred forty-eight female patients were randomized to receive either tropisetron 5 mg (n = 49), tropisetron 2 mg (n = 49), or saline (n = 50) before the induction of anesthesia with thiopental and morphine. Anesthesia was maintained with nitrous oxide and isoflurane. Postoperative analgesia was provided by patient-controlled analgesia with i.v. morphine. The incidence of PONV, the pain score, and the analgesic requirement were recorded for 48 h. There was no difference among groups in patient characteristics, risk factors for PONV, morphine consumption, or side effects. During the first 6 h postoperatively, the incidence of PONV after tropisetron 2 mg and 5 mg were similar and were superior to placebo (P < 0.001). After 6 h, the incidence of PONV increased significantly in patients who had received tropisetron 2 mg (P = 0.01) and was greater than that in patients who had received tropisetron 5 mg (P = 0.001). We conclude that single-dose tropisetron 5 mg is more effective than tropisetron 2 mg in the prevention of PONV after breast surgery.

IMPLICATIONS

Breast surgery is associated with a high incidence of postoperative nausea and vomiting. A single dose of i.v. tropisetron 5 mg is well tolerated and decreases the number of vomiting and nausea episodes after surgery.

The 3' untranslated region of a rice alpha-amylase gene mediates sugar-dependent abundance of mRNA

A decrease in transcript stability is one of the important mechanisms that control the sugar repression of alpha-amylase gene expression in rice suspension cells. In this study, we investigated the function of the 3' untranslated region (3'UTR) of a rice alpha-amylase gene, alpha Amy3, in relation to sugar-dependent accumulation of mRNA. By examining the transient expression of chimeric genes in rice protoplasts, we were able to demonstrate that the alpha Amy3 3'UTR mediated the sugar-dependent repression of fused heterologous gene expression. The same kinetics of accumulation of alpha Amy3 mRNA and reporter mRNA carrying the alpha Amy3 3'UTR in response to glucose deprivation were observed, suggesting that the alpha Amy3 3'UTR is sufficient, and probably the major determinant for controlling the abundance of these transcripts. Functional analysis of two subdomains of alpha Amy3 3'UTR by insertion into a sugar-inducible chimeric gene confirmed their roles in sugar repressibility. The regulatory sequences in the alpha Amy3 3'UTR may act as potent determinants of mRNA stability in response to sugar availability. This finding has important implications for studying the regulatory mechanism of sugar repression in eukaryotes.

The 3' untranslated region of a rice alpha-amylase gene functions as a sugar-dependent mRNA stability determinant

In plants, sugar feedback regulation provides a mechanism for control of carbohydrate allocation and utilization among tissues and organs. The sugar repression of alpha-amylase gene expression in rice provides an ideal model for studying the mechanism of sugar feedback regulation. We have shown previously that sugar repression of alpha-amylase gene expression in rice suspension cells involves control of both transcription rate and mRNA stability. The alpha-amylase mRNA is significantly more stable in sucrose-starved cells than in sucrose-provided cells. To elucidate the mechanism of sugar-dependent mRNA turnover, we have examined the effect of alphaAmy3 3' untranslated region (UTR) on mRNA stability by functional analyses in transformed rice suspension cells. We found that the entire alphaAmy3 3' UTR and two of its subdomains can independently mediate sugar-dependent repression of reporter mRNA accumulation. Analysis of reporter mRNA half-lives demonstrated that the entire alphaAmy3 3' UTR and the two subdomains each functioned as a sugar-dependent destabilizing determinant in the turnover of mRNA. Nuclear run-on transcription analysis further confirmed that the alphaAmy3 3' UTR and the two subdomains did not affect the transcription rate of promoter. The identification of sequence elements in the alpha-amylase mRNA that dictate the differential stability has very important implications for the study of sugar-dependent mRNA decay mechanisms.

The 3' untranslated region of a rice alpha-amylase gene functions as a sugar-dependent mRNA stability determinant

In plants, sugar feedback regulation provides a mechanism for control of carbohydrate allocation and utilization among tissues and organs. The sugar repression of alpha-amylase gene expression in rice provides an ideal model for studying the mechanism of sugar feedback regulation. We have shown previously that sugar repression of alpha-amylase gene expression in rice suspension cells involves control of both transcription rate and mRNA stability. The alpha-amylase mRNA is significantly more stable in sucrose-starved cells than in sucrose-provided cells. To elucidate the mechanism of sugar-dependent mRNA turnover, we have examined the effect of alphaAmy3 3' untranslated region (UTR) on mRNA stability by functional analyses in transformed rice suspension cells. We found that the entire alphaAmy3 3' UTR and two of its subdomains can independently mediate sugar-dependent repression of reporter mRNA accumulation. Analysis of reporter mRNA half-lives demonstrated that the entire alphaAmy3 3' UTR and the two subdomains each functioned as a sugar-dependent destabilizing determinant in the turnover of mRNA. Nuclear run-on transcription analysis further confirmed that the alphaAmy3 3' UTR and the two subdomains did not affect the transcription rate of promoter. The identification of sequence elements in the alpha-amylase mRNA that dictate the differential stability has very important implications for the study of sugar-dependent mRNA decay mechanisms.

Difficult-to-control asthma: clinical characteristics of steroid-insensitive asthma

BACKGROUND

Although widely used, little is known regarding the patterns of response that subjects with severe asthma exhibit to oral glucocorticoid (GC) therapy.

METHODS

We retrospectively reviewed the charts of 164 consecutive adolescents admitted to the National Jewish Medical and Research Center for difficult-to-control asthma. Data collected included medical history, pulmonary function measures by plethysmography, methacholine challenge results, AM cortisol levels, serum IgE, total eosinophil counts (TEC), serum eosinophil cationic protein (ECP), soluble IL-2 receptor (sIL-2R), and spirometry.

RESULTS

Eighty-seven patients (53%) required a GC burst during the hospitalization secondary to poor asthma control. Those requiring a GC burst had a significantly longer history of asthma, a greater degree of bronchial hyperresponsiveness, and lower pulmonary function. Twenty-one patients (24%) failed to respond with a greater than 15% improvement in their AM prebronchodilator FEV1 after the GC burst and were termed steroid insensitive (SI). Although those with SI asthma had a similar duration of asthma, they required oral GC therapy at a younger age, required a larger maintenance oral GC dose on admission, and were more likely to be African-American, compared with those with steroid-sensitive asthma. Furthermore, two distinct spirometry patterns were noted among the SI asthmatic subjects: "chaotic" and "nonchaotic." Patients with the chaotic pattern were characterized by a significant degree of variability (greater than 30%) in daily pulmonary function, whereas those with nonchaotic, SI asthma were characterized by less than 15% variability in daily lung function. Those with nonchaotic SI were diagnosed with asthma and treated with oral GCs at a later age.

CONCLUSIONS

This retrospective study suggests that SI asthma is quite common (25%) among adolescents with severe asthma evaluated at a national referral center. In addition, two distinct patterns of SI asthma have been identified that may constitute different pathophysiologic processes. Finally, the overrepresentation of African-Americans in the SI group supports the need for further epidemiologic studies investigating the prevalence of SI asthma and the impact early asthma intervention may have on this severe form of asthma.

Occupational chromate allergy in Singapore: a study of 87 patients and a review from 1983 to 1995

BACKGROUND

The prevalence of chromate allergy among all patients tested at the Contact and Occupational Dermatoses Clinic at the National Skin Centre in Singapore had fallen progressively from 1983 to 1989. Chromate has also become a less common occupational allergen because of the decline in the number of cases of allergic contact dermatitis from cement.

OBJECTIVE

The aim of this report was to study and update the epidemiology of occupational chromate allergy among workers seen in a tertiary dermatology referral centre in Singapore from 1990 to 1995 and to review the changing trends of occupational chromate allergy in our local setting since 1983. The occurrence of concomitant contact allergens among was also studied.

METHODS

All patients diagnosed to have occupational allergic contact dermatitis together with positive reactions to chromate, at the Joint Occupational Dermatosis Clinic at the National Skin Centre in Singapore, between January 1990 to December 1995, were included. Causes of chromate allergy and frequency of occurrence of concomitant contact allergens among construction and nonconstruction workers were compared.

RESULTS

Eight hundred and fifty workers were seen during the 6-year-study period. Six hundred and thirty three (74.5%) were diagnosed to have occupational contact dermatitis, of which 257 (40.6%) had allergic contact dermatitis. Eighty-seven (33.8%) of these workers had positive reaction to chromate on patch testing. Ninety-five percent of these workers were men with a mean age of 33.4 years. The construction industry contributed 59% of the workers with chromate allergy. Cement (61%) remained the most common source of chromate allergy in our workers, and chromate from sources other than cement (39%) accounted for the rest. Of workers allergic to chromate from cement, 96% (51 of 53) came from the construction industry. Sixty percent of the workers with chromate allergy had concomitant contact allergens and the coexistence of two or more allergens was significantly more common among nonconstruction workers (53%) than construction workers (22%). The three most common concomitant contact allergens were cobalt (28%), rubber chemicals (21%) and nickel (18%). Nonconstruction workers had significantly higher rates of nickel allergy (36% v 6%) than construction workers (P < .03). Simultaneous reactivity to cobalt and nickel was also significantly more common among nonconstruction workers (22%) than construction workers (6%) (P < .03).

CONCLUSION

Chromate has progressively become a less common occupational allergen at the National Skin Centre in Singapore from 1983 to 1989, because of a progressive fall in the number of cases of allergic contact dermatitis from cement. However, our study showed that occupational chromate allergy had now increased from 1990 to 1995, because of an increase in chromate allergy from sources other than cement. Chromate allergy from cement is declining, although still frequent, and sources other than cement are increasing in recent years. Concomitant nickel allergy, as well as simultaneous nickel and cobalt allergies, were more common among nonconstruction workers than construction workers.

Postpartum patients have slightly prolonged neuromuscular block after mivacurium

Postpartum patients have decreased plasma cholinesterase activity, which may slow the metabolism of mivacurium. We compared the duration of a mivacurium neuromuscular block in 11 women undergoing postpartum tubal ligation 36-99 h after delivery with that in 11 control women undergoing gynecological surgery. Anesthesia was induced with propofol and fentanyl and maintained with propofol and nitrous oxide. Neuromuscular block was monitored by electromyography, and the ulnar nerve was stimulated transcutaneously using a train-of-four pattern. Patients received a bolus dose of mivacurium 0.15 mg/kg. The median (range) duration of neuromuscular block until 25% recovery of the first twitch response was longer in the postpartum group, 19.4 (15.6-25.2) min, compared with the control group, 16.3 (11.0-23.4) min (P = 0.04). The median (range) plasma cholinesterase activity was decreased in the postpartum group, 4.0 (0.1-5.5) kU/L, compared with the control group, 7.1 (6.2-10.0) kU/L (P < 0.001). The duration of neuromuscular block was inversely correlated with cholinesterase activity (Kendall rank correlation tau = -0.43, P = 0.005). The slight prolongation of neuromuscular block should not be significant clinically.

IMPLICATIONS

Postpartum patients have decreased amounts of the plasma cholinesterase enzyme. This would slow the metabolism of the muscle relaxant mivacurium. However, the duration of muscle paralysis is only prolonged by approximately 3 min, which would not normally cause any significant problems.

Decreased thiopental requirements in early pregnancy

BACKGROUND

Anesthetic requirements for inhalational agents are decreased during pregnancy, but there are no data regarding requirements for intravenous agents. The quantal dose-response curves for thiopental were calculated for 70 nonpregnant women having gynecologic surgery and for 70 pregnant women of 7-13 weeks' gestation having elective abortions.

METHODS

Groups of 10 patients were given 2, 2.4, 2.8, 3.3, 3.8, 4.5, or 5.3 mg/kg thiopental as a bolus dose during a period of 10 s. Two minutes later, patients were asked to open their eyes as a test for hypnosis. Patients who did not open their eyes were given a 10-s, 50-Hz, 80-mA transcutaneous tetanic electrical stimulus to the ulnar nerve as a test for anesthesia. Purposeful movement indicated that there was no anesthesia. Log dose-response curves for hypnosis and anesthesia were calculated after logit transformation.

RESULTS

In the nonpregnant women, the median effective doses (ED50s) (95% confidence interval) for hypnosis and anesthesia were 3.1 (2.8-3.4) mg/kg and 4.9 (4.5-5.4) mg/kg, whereas in the pregnant women the corresponding ED50s were 2.6 (2.3-2.8) mg/kg and 4 (3.7-4.4) mg/kg. In the non-pregnant women, the ED95s (95% CI) for hypnosis and anesthesia were 4.4 (3.9-5.4) mg/kg and 6.4 (5.7-7.9) mg/kg, whereas in the pregnant women the corresponding ED95s were 3.7 (3.3-4.5) mg/kg and 5.2 (4.7-6.3) mg/kg. The pregnant to nonpregnant relative median potency (95% CI) ratio for hypnosis was 0.83 (0.67-0.96) and for anesthesia it was 0.82 (0.62-0.94).

CONCLUSIONS

The dose of thiopental for hypnosis was 17% less and that for anesthesia was 18% less in pregnant women of 7-13 weeks' gestation compared with that in nonpregnant women.

Single-dose pharmacokinetics of paracetamol and its conjugates in Chinese non-insulin-dependent diabetic patients with renal impairment

OBJECTIVE

A single oral dose of paracetamol (20 mg.kg-1) was given to 38 Chinese patients with non-insulin-dependent diabetes mellitus (NIDDM) who had either normal renal function or varying degrees of renal impairment, with creatinine clearances ranging from 4 to 123 ml.min-1.1.73 m-2. The plasma and urinary concentrations of paracetamol and its major metabolites were measured by high-performance liquid chromatography (HPLC).

RESULTS

The absorption and elimination of paracetamol were unaffected by renal impairment. However, the area under the plasma concentration time curve and the elimination half-life of paracetamol metabolites increased significantly with worsening renal insufficiency. Mean renal clearances of paracetamol and its conjugates were significantly reduced in these subjects. There was no evidence of altered metabolic activation with renal impairment.

CONCLUSION

The results demonstrate that paracetamol disposition is minimally affected by diabetic nephropathy; however, extensive accumulation of conjugates may occur.

Minimum alveolar concentration of halothane and enflurane are decreased in early pregnancy

BACKGROUND

Minimum alveolar concentration (MAC) of isoflurane is decreased in early pregnancy but it is not known whether this occurs to the same extent with other inhalational anesthetics. The MAC of halothane and enflurane were compared in pregnant women undergoing elective termination of pregnancy and in nonpregnant women.

METHODS

We studied 16 pregnant women scheduled for termination of pregnancy at 8 to 13 weeks gestation and 16 non-pregnant patients undergoing laparoscopic sterilization. Eight patients in each group received halothane and the others received enflurane. After inhalational induction of anesthesia and tracheal intubation, MAC was determined in each patient by observing the motor response to a 10-s, 50-Hz, 80-mA transcutaneous electric tetanic stimulus to the ulnar nerve at varying concentrations of either halothane or enflurane. The end-tidal concentration of inhalational anesthetic was kept constant for at least 15 min before each stimulus and the concentration was varied ultimately in steps of 0.05 vol% (halothane) or 0.10 vol% (enflurane) until a sequence of three alternate responses (move, not move, move) or (not move, move, not move) was obtained. Minimum alveolar concentration for each person was taken as the mean of the two concentrations just permitting and just preventing movement, and MAC for the group was the median of individual MAC values. Confidence intervals were calculated for the percentage decrease in MAC for pregnant women compared with nonpregnant women.

RESULTS

The median (range) MAC of halothane, 0.58 vol% (0.53 to 0.58), and enflurane, 1.15 vol% (0.95-1.25), in the pregnant women were less than those in the nonpregnant women, 0.75 vol% (0.70 to 0.78), P = 0.0005 and 1.65 vol% (1.45 to 1.75), P = 0.0007, respectively. The percentage decrease (95% CI) in MAC for pregnant women was 27% (20 to 27%) for halothane and 30% (24 to 36%) for enflurane.

CONCLUSIONS

The MAC of halothane and enflurane were reduced by a similar degree in pregnant women at 8 to 13 weeks gestation compared with nonpregnant women.

Sugars act as signal molecules and osmotica to regulate the expression of alpha-amylase genes and metabolic activities in germinating cereal grains

The molecular mechanisms that initiate and control the metabolic activities of seed germination are largely unknown. Sugars may play important roles in regulating such metabolic activities in addition to providing an essential carbon source for the growth of young seedlings and maintaining turgor pressure for the expansion of tissues during germination. To test this hypothesis, we investigated the physiological role of sugars in the regulation of alpha-amylase gene expression and carbohydrate metabolism in embryo and endosperm of germinating rice seeds. RNA gel blot analysis revealed that in the embryo and aleurone cells, expression of four alpha-amylase genes was differentially regulated by sugars via mechanisms beyond the well-known hormonal control mechanism. In the aleurone cells, expression of these alpha-amylase genes was regulated by gibberellins produced in the embryo and by osmotically active sugars. In the embryo, expression of two alpha-amylase genes and production of gibberellins were transient, and were probably induced by depletion of sugars in the embryo upon imbibition, and suppressed by sugars influx from the endosperm as germination proceeded. The deferential expression of the four alpha-amylase genes in the embryo and aleurone cells was probably due to their markedly different sensitivities to changes in tissue sugar levels. Our study supports a model in which sugars regulate the expression of alpha-amylase genes in a tissue-specific manner: via a feedback control mechanism in the embryo and via an osmotic control mechanism in the aleurone cells. An interactive loop among sugars, gibberellins, and alpha-amylase genes in the germinating cereal grain is proposed.

Postpartum changes in the minimum alveolar concentration of isoflurane

BACKGROUND

Minimum alveolar concentration (MAC) is decreased in pregnancy, but it is not known how quickly after delivery MAC returns to normal. We measured the MAC of isoflurane in a group of women undergoing elective tubal ligation after delivery.

METHODS

After delivery, 20 patients underwent inhalational induction of anesthesia with isoflurane and tracheal intubation. MAC was determined in each patient by observing the response to a 10-s, 50-Hz, 80-mA transcutaneous tetanic electric stimulus to the ulnar nerve at various concentrations of isoflurane. The end-tidal concentration of isoflurane was kept constant for at least 10 min before each stimulus, and the concentration of isoflurane was ultimately varied in steps of 0.05 vol% until we obtained a sequence of three alternate responses: move-not move-move or not move-move-not move. The MAC for each subject was taken as the mean of the two concentrations just permitting and just preventing movement. A venous blood sample was taken immediately before induction of anesthesia for measurement of progesterone concentration. MAC was compared with time after delivery and plasma progesterone concentrations by Kendall's rank correlation.

RESULTS

There was a positive correlation between MAC and the time after delivery (P < 0.001). The median MAC of isoflurane was 0.775 vol% (range 0.675-0.775 vol%) in five women 24-36 h postpartum. MAC was more variable, 0.825 vol% (0.675-0.975 vol%) in nine women 36-72 h postpartum, whereas six patients more than 72 h postpartum had a MAC of 1.125 vol% (1.025-1.175 vol%). The correlation between MAC and plasma progesterone concentration was almost statistically significant (P = 0.060).

CONCLUSIONS

The MAC of isoflurane was reduced in women 24-36 h postpartum and gradually increased to normal values by 72 h postpartum.

Massive lingual swelling following palatoplasty. An unusual cause of upper airway obstruction

We report a case of upper airway obstruction as a result of delayed massive lingual swelling following routine cleft palate repair in an otherwise healthy 12-month-old girl. We believe that ischaemia and venous congestion were the causes of macroglossia, after prolonged use of the Digman Dott tongue retractor. In any difficult and lengthy repair, we recommend the prophylactic insertion of a nasopharyngeal airway under direct vision by the surgeons after surgery to prevent potential upper airway obstruction.

Decreased minimum alveolar concentration of isoflurane in pregnant humans

BACKGROUND

Minimum alveolar concentration (MAC) is decreased in pregnant animals, but this change has not been demonstrated in humans, probably because of ethical considerations. It is less problematic to determine MAC in pregnant women undergoing termination of pregnancy, however, and therefore we compared the MAC of isoflurane in these women with the MAC in matched nonpregnant women.

METHODS

Patients underwent inhalational induction of anesthesia with isoflurane and tracheal intubation. MAC was determined in each patient by testing the response to a 10-s, 50-Hz, 80-mA transcutaneous tetanic electrical stimulus to the ulnar nerve at varying concentrations of isoflurane. The end-tidal concentration of isoflurane was kept constant for 10 min before each stimulus and the concentration of isoflurane ultimately varied in steps of 0.05% until we obtained a sequence of three alternate responses (move, not move, move) or (not move, move, not move). MAC for each patient was taken as the mean of the two concentrations just permitting and just preventing movement. MAC for the group was taken as the median of the individual MAC values. A blood sample was taken immediately before induction of anesthesia for measurement of progesterone concentrations. Data were compared between groups by the Mann-Whitney test.

RESULTS

The median (range) MAC for isoflurane in the pregnant group, 0.775% (0.675-0.825), was less than that in the nonpregnant group, 1.075% (1.025-1.175) (P < 0.001). The median (range) plasma progesterone concentration in the pregnant group, 63.4 (0.8-106) nM, was greater than that in the nonpregnant group, 8.4 (0.7-66) nM (P < 0.02).

CONCLUSIONS

The MAC of isoflurane was reduced by 28% in pregnant women at 8-12 weeks' gestation compared with that of nonpregnant controls.

Drug overdosage and other poisoning in Hong Kong--the Prince of Wales Hospital (Shatin) experience

From 1988 to 1991, 732 patients (91.1% Chinese) were admitted to four general medical wards at the Prince of Wales Hospital in Hong Kong with acute poisoning. The patients were predominantly female (68.9%) and relatively young (86.3% below the age of 40). Further analysis of 655 patients indicates that the vast majority of patients (96%) were admitted after self-poisoning with drugs or chemicals while 4% of cases were due to accidental poisoning. The main agents used by the former group included hypnotics/sedatives (33.1%), household products (15.7%), and analgesics (13.7%). There were nine deaths (1.4%). When compared to other Western countries, two important variations in the pattern of acute poisoning were seen. A substantial proportion of drugs ingested by our patients were not precisely identified. 'Dettol', a household product, was commonly used for self-poisoning in Hong Kong. Territory-wide studies of longer duration are needed to provide the physicians in Hong Kong with much needed information on the incidence and the pattern of acute poisoning.

Novel gene expression system for plant cells based on induction of alpha-amylase promoter by carbohydrate starvation

The 5' regulatory region and putative signal sequence of a rice alpha-amylase gene, alpha Amy8, was fused to a bacterial gene encoding beta-glucuronidase (GUS) and introduced into rice, tobacco, and potato via Agrobacterium-mediated transformation systems. Expression of this chimeric gene in suspension cells of transgenic plants was suppressed by the presence of sucrose in the medium and induced by its absence. Induction or suppression of GUS expression in transgenic rice could be reversed by the deprivation or replenishment, respectively, of sucrose in the medium. The expressed GUS fusion protein was translocated to the endoplasmic reticulum, modified by glycosylation, and secreted into the culture medium of transgenic cells. In the presence of a glycosylation inhibitor, tunicamycin, the enzymatically active form of GUS was assembled in the endoplasmic reticulum. The yield of GUS secreted by transgenic cells was estimated to be as high as 40% of total secreted proteins. The reversible induction of the alpha-amylase promoter in culture cells by sugar level in the medium provides an excellent inducible expression system for basic research in plant science. Combination of the alpha-amylase promoter and signal sequence also offers a novel approach for large scale production of low cost, easily purified, secreted recombinant proteins.

Disease profiles in Chinese in Hong Kong: an analysis of the primary diagnoses in 561 acute hospital medical admissions

Little is known about the disease profiles in Chinese living in an urbanized community like Hong Kong. Accordingly, the discharge summaries of 561 acute hospital medical admissions were reviewed and the primary diagnoses (the main reason for admission or the most important clinical problem) were coded according to the International Classification of Diseases. Our data indicate that cardiovascular diseases are the most important cause of acute medical admissions and mortality and that gastrointestinal hemorrhage is very common amongst the Chinese in Hong Kong.

Agrobacterium-mediated production of transgenic rice plants expressing a chimeric alpha-amylase promoter/beta-glucuronidase gene

We have successfully transferred and expressed a reporter gene driven by an alpha-amylase promoter in a japonica type of rice (Oryza sativa L. cv. Tainung 62) using the Agrobacterium-mediated gene transfer system. Immature rice embryos (10-12 days after anthesis) were infected with an Agrobacterium strain carrying a plasmid containing chimeric genes of beta-glucuronidase (uidA) and neomycin phosphotransferase (nptII). Co-incubation of potato suspension culture (PSC) with the Agrobacterium inoculum significantly improved the transformation efficiency of rice. The uidA and nptII genes, which are under the control of promoters of a rice alpha-amylase gene (alpha Amy8) and Agrobacterium nopaline synthase gene (nos), respectively, were both expressed in G418-resistant calli and transgenic plants. Integration of foreign genes into the genomes of transgenic plants was confirmed by Southern blot analysis. Histochemical localization of GUS activity in one transgenic plant (R0) revealed that the rice alpha-amylase promoter functions in all cell types of the mature leaves, stems, sheaths and roots, but not in the very young leaves. This transgenic plant grew more slowly and produced less seeds than the wild-type plant, but its R1 and R2 progenies grew normally and produced as much seeds as the wild-type plant. Inheritance of foreign genes to the progenies was also confirmed by Southern blot analysis. These data demonstrate successful gene transfer and sexual inheritance of the chimeric genes.

Assessment of erythrocyte deformability by constant flow filtration technique: analysis of factors influencing the initial pressure

When filtering red blood cells (RBC) resuspended into buffer at constant flow, the pressure-time curve is dependent on erythrocyte deformability (E.D) and also on the plugging of pores by RBC or leukocytes (WBC). To understand the influence of these 3 factors, we used an apparatus with: 1) a constant flow syringe (Bioblock) (1.56 ml/mn); 2) a pressure transducer (Statham P23 ID); 3) a recorder (Gould); 4) a 5 micron polycarbonate filter (Nuclepore) housed in a lucite block according to USAMI & al. (1). Resuspensions of RBC from 4 to 14% haematocrit with 0 to 600 WBC/mm3 were investigated. Results indicate that: 1/ The first inflexion point of the pressure-time curve (initial pressure leading to calculation of beta) is related to the RBC's deformability; 2/beta is (in our experimental conditions) dependent on the WBC number; 3/beta seems very sensitive to deformability changes as shown by rapid increases induced by osmolarity changes.