Essential functions of Inositol hexakisphosphate (IP6) in Murine Leukemia Virus replication

We have investigated the function of inositol hexakisphosphate (IP6) and inositol pentakisphosphate (IP5) in the replication of murine leukemia virus (MLV). While IP6 is known to be critical for the life cycle of HIV-1, its significance in MLV remains unexplored. We find that IP6 is indeed important for MLV replication. It significantly enhances endogenous reverse transcription (ERT) in MLV. Additionally, a pelleting-based assay reveals that IP6 can stabilize MLV cores, thereby facilitating ERT. We find that IP5 and IP6 are packaged in MLV particles. However, unlike HIV-1, MLV depends upon the presence of IP6 and IP5 in target cells for successful infection. This IP6/5 requirement for infection is reflected in impaired reverse transcription observed in IP6/5-deficient cell lines. In summary, our findings demonstrate the importance of capsid stabilization by IP6/5 in the replication of diverse retroviruses; we suggest possible reasons for the differences from HIV-1 that we observed in MLV.

Omicron Spike confers enhanced infectivity and interferon resistance to SARS-CoV-2 in human nasal tissue

Omicron emerged following COVID-19 vaccination campaigns, displaced previous SARS-CoV-2 variants of concern worldwide, and gave rise to lineages that continue to spread. Here, we show that Omicron exhibits increased infectivity in primary adult upper airway tissue relative to Delta. Using recombinant forms of SARS-CoV-2 and nasal epithelial cells cultured at the liquid-air interface, we show that mutations unique to Omicron Spike enable enhanced entry into nasal tissue. Unlike earlier variants of SARS-CoV-2, our findings suggest that Omicron enters nasal cells independently of serine transmembrane proteases and instead relies upon metalloproteinases to catalyze membrane fusion. Furthermore, we demonstrate that this entry pathway unlocked by Omicron Spike enables evasion from constitutive and interferon-induced antiviral factors that restrict SARS-CoV-2 entry following attachment. Therefore, the increased transmissibility exhibited by Omicron in humans may be attributed not only to its evasion of vaccine-elicited adaptive immunity, but also to its superior invasion of nasal epithelia and resistance to the cell-intrinsic barriers present therein.

Omicron Spike confers enhanced infectivity and interferon resistance to SARS-CoV-2 in human nasal tissue

Omicron emerged following COVID-19 vaccination campaigns, displaced previous SARS-CoV-2 variants of concern worldwide, and gave rise to lineages that continue to spread. Here, we show that Omicron exhibits increased infectivity in primary adult upper airway tissue relative to Delta. Using recombinant forms of SARS-CoV-2 and nasal epithelial cells cultured at the liquid-air interface, enhanced infectivity maps to the step of cellular entry and evolved recently through mutations unique to Omicron Spike. Unlike earlier variants of SARS-CoV-2, Omicron enters nasal cells independently of serine transmembrane proteases and instead relies upon metalloproteinases to catalyze membrane fusion. This entry pathway unlocked by Omicron Spike enables evasion of constitutive and interferon-induced antiviral factors that restrict SARS-CoV-2 entry following attachment. Therefore, the increased transmissibility exhibited by Omicron in humans may be attributed not only to its evasion of vaccine-elicited adaptive immunity, but also to its superior invasion of nasal epithelia and resistance to the cell-intrinsic barriers present therein.

Antiviral HIV-1 SERINC restriction factors disrupt virus membrane asymmetry

The host proteins SERINC3 and SERINC5 are HIV-1 restriction factors that reduce infectivity when incorporated into the viral envelope. The HIV-1 accessory protein Nef abrogates incorporation of SERINCs via binding to intracellular loop 4 (ICL4). Here, we determine cryoEM maps of full-length human SERINC3 and an ICL4 deletion construct, which reveal that hSERINC3 is comprised of two α-helical bundles connected by a ~ 40-residue, highly tilted, "crossmember" helix. The design resembles non-ATP-dependent lipid transporters. Consistently, purified hSERINCs reconstituted into proteoliposomes induce flipping of phosphatidylserine (PS), phosphatidylethanolamine and phosphatidylcholine. Furthermore, SERINC3, SERINC5 and the scramblase TMEM16F expose PS on the surface of HIV-1 and reduce infectivity, with similar results in MLV. SERINC effects in HIV-1 and MLV are counteracted by Nef and GlycoGag, respectively. Our results demonstrate that SERINCs are membrane transporters that flip lipids, resulting in a loss of membrane asymmetry that is strongly correlated with changes in Env conformation and loss of infectivity.

Rapalogs downmodulate intrinsic immunity and promote cell entry of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in immunocompromised individuals is associated with prolonged virus shedding and evolution of viral variants. Rapamycin and its analogs (rapalogs, including everolimus, temsirolimus, and ridaforolimus) are FDA approved as mTOR inhibitors for the treatment of human diseases, including cancer and autoimmunity. Rapalog use is commonly associated with an increased susceptibility to infection, which has been traditionally explained by impaired adaptive immunity. Here, we show that exposure to rapalogs increased susceptibility to SARS-CoV-2 infection in tissue culture and in immunologically naive rodents by antagonizing the cell-intrinsic immune response. We identified 1 rapalog (ridaforolimus) that was less potent in this regard and demonstrated that rapalogs promote spike-mediated entry into cells, by triggering the degradation of the antiviral proteins IFITM2 and IFITM3 via an endolysosomal remodeling program called microautophagy. Rapalogs that increased virus entry inhibited mTOR-mediated phosphorylation of the transcription factor TFEB, which facilitated its nuclear translocation and triggered microautophagy. In rodent models of infection, injection of rapamycin prior to and after virus exposure resulted in elevated SARS-CoV-2 replication and exacerbated viral disease, while ridaforolimus had milder effects. Overall, our findings indicate that preexisting use of certain rapalogs may elevate host susceptibility to SARS-CoV-2 infection and disease by activating lysosome-mediated suppression of intrinsic immunity.

Rapalogs downmodulate intrinsic immunity and promote cell entry of SARS-CoV-2

SARS-CoV-2 infection in immunocompromised individuals is associated with prolonged virus shedding and evolution of viral variants. Rapamycin and its analogs (rapalogs, including everolimus, temsirolimus, and ridaforolimus) are FDA-approved as mTOR inhibitors for the treatment of human diseases, including cancer and autoimmunity. Rapalog use is commonly associated with increased susceptibility to infection, which has been traditionally explained by impaired adaptive immunity. Here, we show that exposure to rapalogs increases susceptibility to SARS-CoV-2 infection in tissue culture and in immunologically naive rodents by antagonizing the cell-intrinsic immune response. By identifying one rapalog (ridaforolimus) that is less potent in this regard, we demonstrate that rapalogs promote Spike-mediated entry into cells by triggering the degradation of antiviral proteins IFITM2 and IFITM3 via an endolysosomal remodeling program called microautophagy. Rapalogs that increase virus entry inhibit the mTOR-mediated phosphorylation of the transcription factor TFEB, which facilitates its nuclear translocation and triggers microautophagy. In rodent models of infection, injection of rapamycin prior to and after virus exposure resulted in elevated SARS-CoV-2 replication and exacerbated viral disease, while ridaforolimus had milder effects. Overall, our findings indicate that preexisting use of certain rapalogs may elevate host susceptibility to SARS-CoV-2 infection and disease by activating lysosome-mediated suppression of intrinsic immunity.

Discovery of a Novel Specific Inhibitor Targeting Influenza A Virus Nucleoprotein with Pleiotropic Inhibitory Effects on Various Steps of the Viral Life Cycle

Influenza A viruses (IAVs) continue to pose an imminent threat to humans due to annual influenza epidemic outbreaks and episodic pandemics with high mortality rates. In this context, the suboptimal vaccine coverage and efficacy, coupled with recurrent events of viral resistance against a very limited antiviral portfolio, emphasize an urgent need for new additional prophylactic and therapeutic options, including new antiviral targets and drugs with new mechanisms of action to prevent and treat influenza virus infection. Here, we characterized a novel influenza A virus nucleoprotein (NP) inhibitor, FA-6005, that inhibited a broad spectrum of human pandemic and seasonal influenza A and B viruses in vitro and protects mice against lethal influenza A virus challenge. The small molecule FA-6005 targeted a conserved NP I41 domain and acted as a potentially broad, multimechanistic anti-influenza virus therapeutic since FA-6005 suppressed influenza virus replication and perturbed intracellular trafficking of viral ribonucleoproteins (vRNPs) from early to late stages. Cocrystal structures of the NP/FA-6005 complex reconciled well with concurrent mutational studies. This study provides the first line of direct evidence suggesting that the newly identified NP I41 pocket is an attractive target for drug development that inhibits multiple functions of NP. Our results also highlight FA-6005 as a promising candidate for further development as an antiviral drug for the treatment of IAV infection and provide chemical-level details for inhibitor optimization.IMPORTANCE Current influenza antivirals have limitations with regard to their effectiveness and the potential emergence of resistance. Therefore, there is an urgent need for broad-spectrum inhibitors to address the considerable challenges posed by the rapid evolution of influenza viruses that limit the effectiveness of vaccines and lead to the emergence of antiviral drug resistance. Here, we identified a novel influenza A virus NP antagonist, FA-6005, with broad-spectrum efficacy against influenza viruses, and our study presents a comprehensive study of the mode of action of FA-6005 with the crystal structure of the compound in complex with NP. The influenza virus inhibitor holds promise as an urgently sought-after therapeutic option offering a mechanism of action complementary to existing antiviral drugs for the treatment of influenza virus infection and should further aid in the development of universal therapeutics.

Opposing activities of IFITM proteins in SARS-CoV-2 infection

Interferon-induced transmembrane proteins (IFITMs) restrict infections by many viruses, but a subset of IFITMs enhance infections by specific coronaviruses through currently unknown mechanisms. We show that SARS-CoV-2 Spike-pseudotyped virus and genuine SARS-CoV-2 infections are generally restricted by human and mouse IFITM1, IFITM2, and IFITM3, using gain- and loss-of-function approaches. Mechanistically, SARS-CoV-2 restriction occurred independently of IFITM3 S-palmitoylation, indicating a restrictive capacity distinct from reported inhibition of other viruses. In contrast, the IFITM3 amphipathic helix and its amphipathic properties were required for virus restriction. Mutation of residues within the IFITM3 endocytosis-promoting YxxФ motif converted human IFITM3 into an enhancer of SARS-CoV-2 infection, and cell-to-cell fusion assays confirmed the ability of endocytic mutants to enhance Spike-mediated fusion with the plasma membrane. Overexpression of TMPRSS2, which increases plasma membrane fusion versus endosome fusion of SARS-CoV-2, attenuated IFITM3 restriction and converted amphipathic helix mutants into infection enhancers. In sum, we uncover new pro- and anti-viral mechanisms of IFITM3, with clear distinctions drawn between enhancement of viral infection at the plasma membrane and amphipathicity-based mechanisms used for endosomal SARS-CoV-2 restriction.

Meeting the Media: Friend or Foe?

For various reasons, the emergency department is an area of interest for the media. As a result, emergency physicians have to prepare for the occasions of being interviewed by the media some day in their career. It is natural to have some anxiety and fear in meeting the media, especially for the inexperienced. However, developing a good relationship with the media would not only benefit the organisation and the specialty, but also the general public as well. This is a review of the preparation, techniques, tricks and pitfalls in dealing with the media, especially in regard to television interviews.

Management of Body Packers in the Emergency Department

Body packing of illicit drugs is one of the means of drug trafficking. Asymptomatic suspects may be brought in by law-enforcement officers for body search of possible drug packing inside the body. Symptomatic body packers may present with gastrointestinal obstruction or toxicity of the leaking drugs inside the packets. Management strategies are largely determined by the modes of presentation. Asymptomatic persons must be persuaded with every effort for consent to the body cavity search as well as treatment for the safe passage of any packed drugs to avoid possible complications and medico-legal sequelae. Abdominal X-rays and computed tomography can be helpful in confirming the presence of drug packets and in identifying possible packet leakage. Gastrointestinal decontamination, whole bowel irrigation, use of specific antidote as well as operative intervention may be indicated. Emergency physicians must be conversant with the medical and legal aspects of the management of these body packers.

Emergency Management North of the Shenzhen River

A study was carried out in a district hospital located close to the Hong Kong - Shenzhen border, in order to get a picture of the epidemiology of diseases and injuries sustained by Hong Kong residents in China. The emergency medical treatment provided and the degree of patient satisfaction were also analysed. The majority of the patients were adult males. Trauma constituted more than 50% of the attendance, with traffic accident and common assault being the leading causes. This group of Hong Kong residents preferred to be treated in Hong Kong hospitals because of perceived better quality of care. There was a high demand on the local ambulance service and this might have financial and resource implications.

A Rare Cause of Necrotizing Fasciitis: Psoas Abscess

Necrotizing fasciitis always carries very high mortality and morbidity rates. It can be due to group A beta-haemolytic streptococci, which are traditionally described as the flesh-eating bacteria. More commonly, it is related to a mixed growth of bacteria that can be secondary to trauma or surgery. Secondary necrotizing fasciitis due to concomitant soft tissue infection is uncommon. We reported a fatal case of necrotizing fasciitis which was caused by a coexisting psoas abscess. A search for concomitant soft tissue infection is warranted in patients presenting with necrotizing fasciitis. This article also reviewed the clinical tools that may help to make an early diagnosis of the disease.

Beware of the Migrating Chest Pain and Widened Mediastinum: Case Series on Aortic Dissection

Objective

Aortic dissection is not a rare life-threatening emergency. Undiagnosed and untreated aortic dissection is associated with a high mortality. A review of cases in the hospital may provide a baseline picture to guide clinical decisions.

Design

Retrospective case review for a period of 3 years and 4 months.

Setting

District general hospital near the Hong Kong – Shenzhen ‘border’ with 24-hour Accident & Emergency service but without cardiothoracic surgical capability.

Population

All cases coded as ‘aortic dissection’ in the computerized ‘Clinical Management System’ of the hospital.

Main outcome measures

Date, sex, age, history of hypertension, presenting symptoms, pulse deficit, chest X-ray findings, pericardial effusion, A&E diagnosis, type of dissection and patient outcome.

Results

From August 1998 to November 2001, 26 cases of aortic dissection were identified. There were 19 males and 7 females. Age range was 26 to 90 years (mean 65.04 ± SD 15.04, median 66.50, mode 65). In the plain chest X-rays, widened superior mediastinum (>8 cm) was present in 19 patients (73.1%) and pleural effusion in three (11.5%). Pericardial effusion was found in six patients (23.1%). As regard to outcome, 11 were discharged home (42.3%), 14 were transferred to cardiothoracic surgical unit (where two subsequently died) and one died in the hospital.

Conclusion

The prevalence of aortic dissection may be more common than is generally appreciated by emergency physicians. Owing to its variable clinical presentations mimicking other diseases, the diagnosis of aortic dissection is easily missed. Higher clinical vigilance should be exercised for this potentially deadly condition.

Broad-spectrum inhibition of common respiratory RNA viruses by a pyrimidine synthesis inhibitor with involvement of the host antiviral response

Our previous screening of 50 240 structurally diverse compounds led to the identification of 39 influenza A virus infection inhibitors (Kao R.Y., Yang D., Lau L.S., Tsui W.H., Hu L. et al. Nat Biotechnol 2010;28:600-605). Further screening of these compounds against common respiratory viruses led to the discovery of compound FA-613. This inhibitor exhibited low micromolar antiviral activity against various influenza A and B virus strains, including the highly pathogenic influenza A strains H5N1 and H7N9, enterovirus A71, respiratory syncytial virus, human rhinovirus A, SARS- and MERS-coronavirus. No significant cellular toxicity was observed at the effective concentrations. Animal studies showed an improved survival rate in BALB/c mice that received intranasal FA-613 treatments against a lethal dose infection of A/HK/415742Md/2009 (H1N1). Further cell-based assays indicated that FA-613 interfer with the de novo pyrimidine biosynthesis pathway by targeting the dihydroorotate dehydrogenase. Surprisingly, FA-613 lost its antiviral potency in the interferon-deficient Vero cell line, while maintaining its inhibitory activity in an interferon-competent cell line which showed elevated expression of host antiviral genes when infected in the presence of FA-613. Further investigation of the specific connection between pyrimidine synthesis inhibition and the induction of host innate immunity might aid clinical development of this type of drug in antiviral therapies. Therefore, in acute cases of respiratory tract infections, when rapid diagnostics of the causative agent are not readily available, an antiviral drug with properties like FA-613 could prove to be very valuable.

'Fracture' of the penis: a case series

OBJECTIVES

To examine the epidemiology of penile 'fracture' and its presenting characteristics in the local population.

DESIGN

Retrospective study.

SETTING

District hospital, Hong Kong.

PATIENTS

Patients with a discharge diagnosis of 'fractured' penis during a 7-year period from August 1998 to August 2005.

MAIN OUTCOME MEASURES

Age, time of attendance, cause, symptoms, signs, emergency department diagnosis, site of rupture, operative findings, and final outcome.

RESULTS

A total of 11 patients were identified. The mean age was 44 years (range, 30-63 years). The interval between time of injury and presentation ranged from 17 minutes to 7 days. Seven (64%) cases were attributed to sexual intercourse, three (27%) to penile manipulation, and one (9%) to rolling over the erect penis during sleep. Ten patients underwent surgery; all had primary suturing of the tunica tear, while two also required primary urethral repair. At follow-up, three (27%) patients had erectile dysfunction, one had mild penile deformity and one had a mild urethral stricture.

CONCLUSION

Emergency physicians and surgeons, as well as family physicians, should be familiar with the presentation of 'fractured' penis, as prompt diagnosis and early surgical repair are instrumental in ensuring a successful outcome with minimal complications. The public should also be educated to seek medical attention immediately, as delay or failure to report may result in permanent physical and psychological disabilities that could otherwise have been avoided.

Is public access defibrillation needed in Hong Kong?

The survival rate for non-traumatic out-of-hospital cardiac arrest in Hong Kong is low (1.25%-1.6%). Despite the reduced time interval between call receipt and first defibrillatory shock to 11.12 minutes during the past decade, the time interval between collapse/recognition and first defibrillatory shock, at 14.25 minutes, is too long. Studies of out-of-hospital cardiac arrest performed in Hong Kong were reviewed to ascertain whether a public access defibrillation programme can improve survival in Hong Kong. Three delays were found in the traditional response by emergency medical service, namely in the collapse/recognise-to-call receipt, call receipt-to-vehicle stops, and vehicle stops-to-first defibrillatory shock time intervals. The first delay is related to public education, while the second and third delays are intrinsic to a dispatched response. A public access defibrillation programme employing responders at scenes of cardiac arrests can eliminate the collapse/recognise-to-call receipt and call receipt-to-vehicle stops time intervals before defibrillation. Possible sites of public access defibrillation could include the airport and other immigration points, which have a high volume of people passing through, with projected figures for out-of-hospital cardiac arrest at these sites supporting this consideration. For successful implementation of public access defibrillation, a comprehensive educational programme and coordination with the emergency medical service are required.

Patient absconding behaviour in a public general hospital: retrospective study

OBJECTIVE

To identify characteristics of patients who abscond from general hospital wards, and to determine patient outcomes.

DESIGN

Retrospective study.

SETTING

In-patient wards of a public general hospital, Hong Kong.

SUBJECTS AND METHODS

Incident reports of 116 absconding episodes over a 20-month period from 1 November 1998 to 30 June 2000 were reviewed. Clinical characteristics, time and reason for absconding, destination of patient, outcomes, and adverse events were recorded.

RESULTS

The majority of patients who absconded were middle-aged males admitted through the Accident and Emergency Department to the specialty of general medicine. Most incidences occurred within 24 hours of admission while in the emergency admission wards. Twelve percent of incidents were repeated episodes of absconding. The most common clinical diagnoses given to this patient group were drug overdose, intoxication, and soft tissue injury. Known drug addicts (29.3%) formed a substantial proportion of the patient group. Forty- seven patients returned to the ward within a few hours, while a further nine (7.8%) re-attended the Accident and Emergency Department of the hospital within 4 days. Several adverse outcomes were recorded: one patient died following a fall from height and two patients committed criminal offences.

CONCLUSION

Patient absconding incidents are an important issue in hospital risk management. They can delay the delivery of appropriate medical treatment and may lead to other adverse patient outcomes, in addition to potential medicolegal consequences.

A cluster of invasive aspergillosis in a bone marrow transplant unit related to construction and the utility of air sampling

BACKGROUND

An investigation was launched to identify the source of a cluster of invasive aspergillosis in the bone marrow transplant unit (BMTU) when construction was taking place on the floor directly below the unit. The utility of air sampling for Aspergillus was examined.

METHODS

Cases of Aspergillus colonization and infection were identified in the BMTU and in the wards adjacent to the construction site. Air sampling was performed in the BMTU before and after room and air duct cleaning and then randomly during a 6-month period, beginning 6 months after construction ended. The results were correlated with the incidence of Aspergillus infections.

RESULTS

The cluster of cases of invasive aspergillosis could not be directly linked to the construction. In the BMTU, the rate of Aspergillus colonization and infection during construction was 2.5 times higher than that for the 6 months before the construction and 2.9 times higher for the adjacent wards. After construction ended, the rates returned to pre-construction rates. Two cases of invasive aspergillosis were observed in the BMTU during random air sampling, but the results of air sampling could not be correlated to cases.

CONCLUSIONS

Although the cluster of cases of invasive aspergillosis could not be linked to the construction, the construction did increase the rates of Aspergillus colonization in the BMTU and adjacent wards. Periodic air samplings could not correlate conidia counts to invasive Aspergillus infection.

Enterobacter sakazakii infections among neonates, infants, children, and adults. Case reports and a review of the literature

Enterobacter sakazakii can cause serious infections especially among the very young and the elderly. It continues to be more common among neonates and infants than adults. Its tropism for the central nervous system in neonates and infants remains a mystery. Among neonates and infants, E. sakazakii has a propensity to cause meningitis resulting in ventriculitis, brain abscess or cyst formation, and development of hydrocephalus requiring ventricular-peritoneal shunt. Computed tomography of the head is therefore useful in following patients with E. sakazakii meningitis. Mortality and morbidity of E. sakazakii meningitis is high, and virtually all patients recovering from the central nervous system infection suffered mental and physical developmental delays. The case-fatality rate decreased among patients with meningitis treated with the third-generation cephalosporins. Most adults with E. sakazakii infection had serious underlying diseases and 50% of the adults with the infection had malignancies. However there has never been a known case of meningitis. Increasing antibiotic resistance among Enterobacter species should lead one to consider using the carbapenems or the newer cephalosporins in combination with a second agent such as an aminoglycoside. Limited data suggest that trimethoprim-sulfamethoxazole may be a useful agent in the treatment of infections caused by the Enterobacter species, especially in view of the production of extended-spectrum beta-lactamases capable of inactivating the cephalosporins and extended-spectrum penicillin.

Prehospital care in Hong Kong

A quick and efficient prehospital emergency response depends on immediate ambulance dispatch, patient assessment, triage, and transport to hospital. During 1999, the Ambulance Command of the Hong Kong Fire Services Department responded to 484,923 calls, which corresponds to 1329 calls each day. Cooperation between the Fire Services Department and the Hospital Authority exists at the levels of professional training of emergency medical personnel, quality assurance, and a coordinated disaster response. In response to the incident at the Hong Kong International Airport in the summer of 1999, when an aircraft overturned during landing, the pre-set quota system was implemented to send patients to designated accident and emergency departments. Furthermore, the 'first crew at the scene' model has been adopted, whereby the command is established and triage process started by the first ambulance crew members to reach the scene. The development of emergency protocols should be accompanied by good field-to-hospital and interhospital communication, the upgrading of decision-making skills, a good monitoring and auditing structure, and commitment to training and skills maintenance.

Delays by patients, emergency physicians, and surgeons in the management of acute appendicitis: retrospective study

OBJECTIVES

To compare the contributions of patients, emergency physicians, and surgeons in the delay of diagnosis and treatment of appendicitis, and the effects of delay on disease stage and complication rate.

DESIGN

Retrospective study.

SETTING

Accident and emergency department of a district public hospital, Hong Kong.

PATIENTS

All patients undergoing emergency appendectomy between August 1998 to September 1999.

MAIN OUTCOME MEASURES

Patient delay in presentation, emergency physician delay in hospital admission, and surgeon delay in performing the operation; operative findings; and postoperative complications.

RESULTS

Of 158 patients undergoing emergency operation, 14 had no pathological diagnosis and four had a diagnosis other than that of acute appendicitis. Of the 140 pathologically confirmed cases of appendicitis, the mean emergency patient delay was greater in advanced appendicitis than it was in simple appendicitis (42.0 hours versus 24.9 hours; P<0.005). The mean emergency physician delay in advanced appendicitis was also greater than it was in simple appendicitis (17.9 hours versus 5.8 hours; P<0.05). The difference in the mean surgeon delay in simple (10.9 hours) and advanced (16.3 hours) appendicitis, however, was not significant. The mean emergency physician delay showed a significant association with the postoperative complication rate (P=0.05). The delay was mainly because of a failure to diagnose the condition and admit the patient at the first visit to the accident and emergency department (22.1%). The diagnostic accuracy showed a significant association with the level of experience of the emergency physician involved (P<0.05).

CONCLUSION

There should be a higher index of suspicion, better surgical training, and better senior supervision at accident and emergency departments, to avoid preventable morbidity and mortality in acute appendicitis.

Influenza in human immunodeficiency virus-infected patients during the 1997-1998 influenza season

A cluster of cases of severe influenzal disease was recognized in HIV-infected individuals during the 1997-1998 influenza season. Both primary influenza pneumonia and concomitant viral and bacterial pneumonia were found.

Tc-99m hexamethylpropylene amine oxime scintigraphy in the diagnosis of brain death and its implications for the harvesting of organs used for transplantation

PURPOSE

Diagnosing brain death is important in managing the comatose patient for whom the continuation of life support is being questioned and when organ harvesting is being considered. The virtual immediate localization of Tc-99m HMPAO to cerebral and cerebellar tissue provides an index of blood perfusion, and its absence denotes brain death. Other methods for assessing brain death include cerebral angiography, MRI, CT imaging after inhalation of stable xenon, electroencephalography, and clinical examination. The contrast material used for angiography may damage harvested organs, and the other studies have significant errors. MRI, CT imaging, and angiography are unsuitable for bedside use.

METHODS

Twenty-three patients, who presented with head trauma, prolonged anoxia or intrinsic brain disease (e.g., glioblastoma multiforme) and who were brain-dead by clinical examination criteria, were referred to the nuclear medicine division for verification of brain death. For adults, approximately 25 mCi Tc-99m hexamethylpropylene amineoxime (HMPAO) was administered intravenously. All patients but one were imaged using a mobile scintillation camera at the bedside.

RESULTS

We demonstrated (1) both cerebral and cerebellar perfusion, (2) neither cerebral nor cerebellar perfusion, (3) cerebral without cerebellar perfusion, and (4) cerebellar without cerebral perfusion. Patients without cerebral perfusion were diagnosed as brain-dead. The significance of a viable cerebellum in the absence of cerebral viability was not fully appreciated, although organs were harvested from such patients. We determined how well the clinical examination criteria held up in the diagnosis of brain death against the new gold standard of Tc-99m HMPAO scintigraphy: Clinical examination criteria correctly predicted brain death only 83% of the time compared with HMPAO scintigraphy.

CONCLUSIONS

Brain death assessment by Tc-99m HM-PAO scintigraphy has proved to be a reliable, safe, and cost-effective bedside method and may have practical application in the assessment of brain death in potential cadaveric donors.

Persistence of episomal HIV-1 infection intermediates in patients on highly active anti-retroviral therapy

Treatment of HIV-1-infected individuals with a combination of anti-retroviral agents results in sustained suppression of HIV-1 replication, as evidenced by a reduction in plasma viral RNA to levels below the limit of detection of available assays. However, even in patients whose plasma viral RNA levels have been suppressed to below detectable levels for up to 30 months, replication-competent virus can routinely be recovered from patient peripheral blood mononuclear cells and from semen. A reservoir of latently infected cells established early in infection may be involved in the maintenance of viral persistence despite highly active anti-retroviral therapy. However, whether virus replication persists in such patients is unknown. HIV-1 cDNA episomes are labile products of virus infection and indicative of recent infection events. Using episome-specific PCR, we demonstrate here ongoing virus replication in a large percentage of infected individuals on highly active anti-retroviral therapy, despite sustained undetectable levels of plasma viral RNA. The presence of a reservoir of 'covert' virus replication in patients on highly active anti-retroviral therapy has important implications for the clinical management of HIV-1-infected individuals and for the development of virus eradication strategies.

Terrestrial gamma ray dose rates of Brunei Darussalam

GPS-indexed in-situ and car-borne survey of terrestrial gamma-ray dose rates were carried out in Brunei and adjacent areas using two portable NaI(Tl) counters. The mean and population weighted average dose rates for Brunei are 34 and 33 nGy/h, respectively. The car-borne data and the in-situ data when spectral analysed separately, were found to show fractal behaviour with D of 1.7 and 1.8, respectively. A contour map of the dose rates was also produced.

I-131 orthoiodohippurate assessment of renal function after heart transplantation

PURPOSE

The authors studied the relation between cardiac output (CO) and effective renal plasma flow (ERPF) and compared values from control patients with various cardiac problems with those in a group of study patients who had undergone heart transplantation.

METHODS

The experimental group was divided into three subgroups according to the interval between the time of surgery and the time of the CO-ERPF studies. Group 1 consisted of patients studied fewer than 10 days after surgery; group 2 consisted of patients studied 10 to 20 days after operation; and group 3 consisted of patients studied more than 20 days after operation. Effective renal plasma flow was determined by the single-injection, single plasma sample method, where 50 microCi I-131 orthoiodohippurate was injected intravenously in a single dose and plasma concentrations of radioactivity were determined. The quotient of injected dose radioactivity divided by plasma radioactivity is highly predictive of global ERPF. Cardiac output was measured by thermodilution.

RESULTS

In the control group, a positive linear correlation was found between CO and ERPF; however, the CO:ERPF ratio was elevated, and after heart transplantation, a lag time was observed for as long as 3 weeks in some patients before CO:ERPF ratios returned to control group levels. The regression equation and standard error for the control group was CO = 1.85 + 0.0065 ERPF (+/-0.62) l/min versus 1.433 + 0.0068 ERPF (+/-0.64) l/min for group 3. The correlation coefficients comparing CO with ERPF were r = 0.88, 0.23, 0.51, and 0.85, for the control group and groups 1, 2, and 3, respectively.

CONCLUSION

A localized release of catecholamines from the adrenal gland is proposed to cause ERPF damping after abrupt increases in CO.

Failure to eradicate vancomycin-resistant enterococci in a university hospital and the cost of barrier precautions

OBJECTIVE

To describe the effect of infection control interventions on the incidence of vancomycin-resistant enterococci (VRE), the utility of pharyngeal cultures for surveillance for VRE colonization, and the cost of barrier precautions.

DESIGN

Evaluation of the occurrence of VRE infection or colonization, rates of vancomycin use, results of surveillance cultures before and after interventions, and the cost of increased barrier precautions.

SETTING

University of Massachusetts Medical Center, a 347-bed tertiary-care teaching hospital with eight intensive-care units, one burn unit, and one bone marrow transplant unit.

PARTICIPANTS

Patients in the intensive-care units and staff who were involved with patients colonized or infected with VRE.

METHODS

Infection control interventions included placement of patients with VRE in private rooms, strict contact isolation, cohorting of patient and nursing staff, prohibiting of equipment sharing, and monitoring of compliance with the vancomycin restriction policy, with hand washing, and of the adequacy of environmental cleaning. Both rectal and pharyngeal cultures were obtained from patients at the beginning of the outbreak, and the utility of pharyngeal cultures was evaluated. The cost of barrier precautions was estimated by comparing the cost of glove and gown use before and after the outbreak began.

RESULTS

The interventions decreased the number of new cases of VRE, but total eradication of VRE was not achieved. Compliance with the room-cleaning protocol was 91% (141/155 observations). Hand washing following interaction with patients who were not in isolation was 51%, vs 100% for patients in isolation. Overall, handwashing compliance was 71% (319/449): 56% (130/231) for physicians and 86% (187/218) for nurses (P<.0001). The mean number of doses of vancomycin dispensed per 1,000 patient days decreased from 145 to 114 per 1,000 patient days (P<.001). Compliance with vancomycin-use guidelines was 85%. Forty-six (77%) of 60 surveillance rectal swabs yielded enterococci, as compared to only 4 (11%) of 36 pharyngeal cultures (P<.0001). Expenses on glove and gowns alone increased by over $11,000 per year since the epidemic began.

CONCLUSIONS

Implementation of the various infection control measures did not eradicate VRE cases from the hospital. Rectal cultures were more useful than pharyngeal cultures for surveillance of VRE. Controlling VRE epidemics can be costly.

Infections associated with implantable cardioverter defibrillators placed transvenously and via thoracotomies: epidemiology, infection control, and management

In 1993, the incidence of infection associated with implantable cardioverter defibrillators (ICDs) excluding generator, lead, and patch placements was 16.7% at our institution. Eighty-eight percent of the ICD implantations were two-staged procedures: the cardiologists performed the electrophysiologic studies in their laboratories, and implantations were performed in the operating rooms a few hours to a few days later by cardiothoracic surgeons. In 1994, both the electrophysiologic studies and ICD implantations were performed in the operating rooms without waiting periods. From 1993 to 1995, the proportion of ICDs placed transvenously increased from 56% to 100%, whereas the proportion of two-staged ICD placements decreased from 88% to zero. From 1992 to 1993 the infection rate decreased concomitantly from 16.7% to zero. From 1992 through 1995, the infection rate for implantable ICDs alone was 4.8%, and the overall infection rate for implantable ICDs (including generator, lead, and patch placements) was 6.9%, comparable to the rate reported in the literature (2.2% to 7.2%). The elimination of the two-stage procedure and the increased proportion of transvenously placed ICDs has contributed to the decrease in infection rate.

Long-term laboratory contamination by Mycobacterium abscessus resulting in two pseudo-outbreaks: recognition with use of random amplified polymorphic DNA (RAPD) polymerase chain reaction

Beginning in 1993, an increase in clinical isolates of Mycobacterium abscessus was observed in a single hospital microbiology laboratory. This involved a cluster of four patients in June 1993 and five patients and a quality-control culture of distilled water in May 1994. Twenty-three M. abscessus isolates recovered between 1991 and 1996 were compared by random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). Sixteen of 21 clinical isolates recovered over a 6-year period and the distilled water isolate had identical RAPD-PCR patterns consistent with a single strain or clone. Only six of 15 patients had findings suggestive of clinical disease. Since the use of in-house-prepared distilled water was discontinued, no further laboratory contamination of clinical specimens has been observed. Molecular typing was the key to defining distilled water as the source of this pseudo-outbreak. Recognition of such outbreaks is important for prevention of unnecessary therapeutic and diagnostic interventions.

Safety of prolonging peripheral cannula and i.v. tubing use from 72 hours to 96 hours

OBJECTIVE

To compare the rates of phlebitis of peripheral intravenous lines left in place for 72 hours versus rates of those left in place 96 hours.

DESIGN

A prospective, nonrandomized study.

SETTING

A university teaching hospital with 375 beds.

PATIENTS

Consecutive adult patients who received peripheral intravenous lines and were admitted to the wards.

MEASUREMENTS

The phlebitis rates were monitored by the i.v. Team for 1 month according to a predetermined definition for phlebitis: palpable cord or at least two of the following: tenderness, warmth, erythema, and induration.

RESULTS

A total of 2503 peripheral lines were evaluable. The overall phlebitis rate was 6.8%. The phlebitis rates for lines left in for 72 and 96 hours were not significantly different (3.3% vs 2.6%, p = 1.000) by Fisher's Exact Test and survival analysis. It was estimated that in 1 month approximately 300 intravenous lines potentially could be prolonged beyond 72 hours; 215 lines were changed at 72 hours despite no signs of inflammation, 61 lines were kept till 96 hours, and 19 lines were kept beyond 96 hours.

CONCLUSIONS

Phlebitis rate for our peripheral intravenous catheters at 96 hours was not significantly different from that at 72 hours. If intravenous cannulas and lines were prolonged to 96 hours, a potential cost saving of $61,200 per year could be realized.

The epidemiology of fecal carriage of vancomycin-resistant enterococci

An outbreak of vancomycin-resistant enterococci (VRE) began at the University of Massachusetts Medical Center in May 1993. As of September 1995, we had a total of 253 patients infected or colonized with VRE, with consequent increasing demand for private rooms. We analyzed results of surveillance cultures for VRE of 49 patients known to be colonized or infected with VRE. Of these, 34 (70%) were classified as persistent carriers, defined as patients with at least three consecutively positive cultures from any site taken over at least a 2-week period. The length of carriage varied from 19 to 303 days (median, 41 days); 11 patients were converters, defined as patients with three consecutive negative cultures from all previously colonized sites taken over a 3-week period. These patients were free of VRE for 39 to 421 days (median, 142 days). Four were recolonizers after they were documented to be clear of VRE for 33 to 106 days. VRE carriage tends to be prolonged, and hospitalization of patients with VRE will require continued isolation and contact precautions for control of transmission.

Itraconazole maintenance treatment for histoplasmosis in AIDS: a prospective, multicenter trial

PURPOSE

To study the efficacy and safety of maintenance treatment with itraconazole for disseminated histoplasmosis in patients with AIDS.

PATIENTS AND METHODS

This was a prospective, multicenter, open-label study conducted at university-based hospitals participating in the AIDS Clinical Trial Group (ACTG). Forty-six AIDS patients with mild to moderate disseminated histoplasmosis who had successfully completed 12 weeks of induction treatment with itraconazole were treated with itraconazole, 200 mg once daily (42 patients) or 400 mg once daily (4 patients). Patients were followed at monthly intervals with clinical and laboratory assessment for relapse or toxicity. Primary outcome measures were relapse of histoplasmosis and survival. Secondary outcome measures included drug-limiting toxicity and changes in serum and urine Histoplasma polysaccharide antigen (HPA) levels.

RESULTS

Two patients relapsed during a median follow-up period of 87 weeks. The 1-year relapse-free rate was estimated to be 95.3% (95% CI, 85.3%-99.7%). One relapse may have been related to poor adherence to treatment and the second to concurrent administration of rifampin. From the start of maintenance treatment, the estimated 1-year survival rate was 73.0% (95% CI, 67.5%-77.9%). Five patients discontinued treatment because of suspected drug toxicity, three of whom had possible or probable hepatotoxicity. Median serum and urine HPA levels declined significantly during treatment. The only patient in whom antigen levels rose >2 U developed clinical relapse 1 week later; antigen levels were unavailable in the other relapsing patient.

CONCLUSIONS

Itraconazole, 200 mg daily, is effective in preventing relapse of disseminated histoplasmosis in patients with AIDS. It is generally well tolerated, but clinicians should be alert for drug interactions and possible hepatotoxicity.

Treatment of histoplasmosis with fluconazole in patients with acquired immunodeficiency syndrome. National Institute of Allergy and Infectious Diseases Acquired Immunodeficiency Syndrome Clinical Trials Group and Mycoses Study Group

PURPOSE

This study assesses the efficacy and safety of fluconazole therapy in patients with acquired immunodeficiency syndrome (AIDS) and mild to moderately severe manifestations of disseminated histoplasmosis.

PATIENTS AND METHODS

This was a multicenter, open-label, nonrandomized prospective trial. All patients had AIDS and disseminated histoplasmosis. Patients were treated with 1,200 mg of fluconazole given by mouth once on the first day, then 600 mg once daily for 8 weeks, and those patients who improved clinically were then assigned fluconazole maintenance therapy 200 mg once daily for at least 1 year. Interim analysis revealed a high failure rate (10 of 20, 50%), causing revision of the protocol to increase the fluconazole dose to 1,600 mg given once on the first day, then 800 mg once daily, and the duration to 12 weeks for induction therapy and then 400 mg daily for 1 year for maintenance therapy.

MEASUREMENTS AND MAIN RESULTS

Thirty-six of 49 patients (74%; 95% confidence interval [CI]: 59% to 85%) with mild to moderately severe clinical manifestations who entered into the revised study responded to 800 mg of fluconazole daily for 12 weeks as induction therapy. Of the seven patients who failed induction therapy because of progression of histoplasmosis, one died of the infection. Of 36 patients who entered into the maintenance phase of the study receiving 400 mg of fluconazole daily for 1 year, 11 (30.5%) relapsed, including one who died (2.8%). Two of the 49 patients (4.1%) were removed because of grade 4 adverse events, alkaline phosphatase elevation for one and aspartate aminotransferase elevation in the other. The relapse-free rate at 1 year was 53% (95% CI: 32% to 89%), prompting closure of the study.

CONCLUSIONS

Fluconazole 800 mg daily is a safe and moderately effective induction therapy for mild or moderately severe disseminated histoplasmosis in patients with AIDS. On the basis of historic comparison, fluconazole 400 mg daily is less effective than itraconazole 200 to 400 mg daily or amphotericin B 50 mg given weekly as maintenance therapy to prevent relapse.

Clostridium difficile-associated diarrhea: epidemiology, risk factors, and infection control

OBJECTIVES

To evaluate the effectiveness of specific infection control measures on the incidence of Clostridium difficile-associated diarrhea (CDAD) and to identify risk factors for its development.

SETTING

370-bed, tertiary-care teaching hospital with approximately 12,000 to 15,000 admissions per year.

METHODS

Several infection control measures were implemented in 1991 and 1992, and the attack rates of CDAD were calculated quarterly. Antibiotic use for 1988 through 1993 was analyzed. A case-control study was conducted from January 1992 to December 1992 to identify risk factors for acquisition of CDAD.

RESULTS

From 1989 to 1992, the attack rate of CDAD increased from 0.49% to 2.25%. An increase in antibiotic use preceded the rise in the incidence of CDAD in 1991. Despite implementation of various infection control measures, the attack rate decreased to 1.32% in 1993, but did not return to baseline. Ninety-two cases and 78 controls (patients with diarrhea but with negative toxin assay) were studied. By univariate analysis, history of prior respiratory tract infections (odds ratio [OR], 3.6; 95% confidence interval [CI95], 1.2-10.4), the number of antibiotics, and the duration of exposure to second-generation cephalosporins (OR, 3.55; CI95, 1.47-9.41) and to ciprofloxacin (OR, 7.27; CI95, 1.13-166.0) were related significantly to the development of CDAD. By stepwise logistic regression analysis, only exposure to antibiotics and prior respiratory tract infections (P = .0001 and .0203, respectively) were found to be significant.

CONCLUSION

Antibiotic pressure might have contributed to failure of infection control measures to reduce the incidence of CDAD to baseline.

The Model Physician-Assisted Suicide Act and the jurisprudence of death

A Model Statute to Authorize and Regulate Physician-Assisted Suicide was published in 1996. This article describes the Act and some of its background and effects in detail, showing that it goes further than at first appears. Specifically, the article discusses the background and basic effect of the Act, the principal provisions of the Act and their effects, the morality and jurisprudence of the Act, the argument from autonomy, and the argument from utility. The authors conclude that by ignoring the moral traditions of Western culture, and focusing only on the ethics and anthropology of autonomy and utility, the drafters of the Act justify the dehumanization of the very people the Act is supposed to benefit.

Treatment of vancomycin-resistant Enterococcus faecium infections

OBJECTIVE

To define the clinical characteristics of patients infected with vancomycin-resistant enterococci (VRE) and the outcome of the infections without the availability of effective antimicrobial therapy.

METHODS

Charts of 28 patients with VRE infections were reviewed for demographics, clinical findings at the time of isolation of VRE, underlying medical problems, surgical procedures, invasive devices, treatment with antimicrobial agents, microbiological data, and patients' responses and outcomes.

RESULTS

The infections included 6 cases of bacteremia, 9 surgical site infections (SSIs), 4 cases of peritonitis, 2 pelvic abscesses, 7 urinary tract infections (UTIs), and 2 soft tissue infections (STIs). Four of the 6 bacteremia cases were central-line related and resolved with line removal alone; 1 was treated with a combination product of quinupristin and dalfopristin (Synercid) and 1 had persistent bacteremia in the presence of a ventriculoperitoneal shunt. Seven of 9 SSIs resolved with surgical debridement and 2 of the 9 patients received antibiotics for organisms other than VRE. Similarly, 2 patients with STIs were treated with local debridement and antibiotics directed at organisms other than VRE and 2 patients with pelvic abscesses were treated with drainage and surgical debridement with antibiotics directed at other organisms; the infections resolved completely. Patients with peritonitis were treated with removal of their Tenckhoff catheters, drainage, and irrigation and 1 patient was treated with quinupristin-dalfopristin; 3 of 4 patients were cured. Two of 7 patients with UTIs were treated with nitrofurantoin and their urine cultures showed no growth after treatment; however, most patients with UTIs experienced resolution despite a lack of specific antimicrobial therapy.

CONCLUSIONS

Although no antimicrobial agents are currently available for VRE infections, VRE line-related bacteremias could be treated by line removal alone. Surgical site infections, STIs, and abscesses could be managed by surgical debridement and drainage without specific antimicrobial agents against VRE and UTIs could be resolved with nitrofurantoin or removal of Foley catheters. Removal of foreign devices, debridement, and surgical drainage seemed to be important in the resolution of VRE infections.

Knowledge of the transmission of tuberculosis and infection control measures for tuberculosis among healthcare workers

Two hundred seventy-five of 325 (85%) healthcare workers (HCWs) completed a questionnaire testing their knowledge of transmission of tuberculosis (TB) and infection control measures for TB. Of the 75 HCWs with no patient contact, 49 (65%) felt that masks should be worn, and 40 (53%) would use gowns. In contrast, 175 (88%) of 200 HCWs having contact with patients thought masks should be worn, and 70 (35%) would use gowns (P = .0001 and .0085, respectively). Only 87% of HCWs with patient contact felt that respiratory precautions should be instituted for TB patients. The results of our survey showed that HCWs should be reeducated about TB.

Attitudes toward childbearing and changes in sexual and contraceptive practices among HIV-infected women

BACKGROUND

Women now constitute 12% of persons with acquired immunodeficiency syndrome (AIDS), and three quarters of them are well within their childbearing age.

OBJECTIVE

To determine if women infected with human immunodeficiency virus (HIV) change their attitudes toward childbearing and their sexual and contraceptive practices.

METHODS

Questionnaire and interview.

RESULTS

Forty-six women age 18 to 44 participated; 33 were white, 12 were Hispanic, and 1 was black. Intravenous drug abuse was reported by 65%. Nineteen had symptomatic HIV disease or AIDS. Only 70% said they had received counseling after testing. Of these, 59% said they were counseled on avoiding pregnancy, and 81% said they were counseled on use of condoms. Before testing, 59% had wanted to have children; after testing, only 17% did. Only 4% said they had always used condoms before testing, but 54% said they did after testing; 39% said they used some form of birth control before testing compared with 70% who said they did after testing.

CONCLUSIONS

Counseling was not optimal. Sexual and contraceptive practices changed, but follow-up study will be needed to see if such changes are sustained.

Factors affecting peak expiratory flow variability and bronchial reactivity in a random population sample

BACKGROUND

Bronchial reactivity measurements are widely used in epidemiological studies to provide an objective marker of asthma. There are, however, several potential advantages of measuring peak expiratory flow (PEF) variability instead, particularly in large studies. PEF variability and bronchial reactivity were compared in a population sample to assess the relationships of the two measurements to factors known to be associated with airways disease, and to compare their response rates.

METHODS

Subjects aged 18-65 were randomly selected from the electoral register of an administrative area in eastern England and randomised to attend either for a bronchial challenge test measuring the provocative dose of methacholine producing a 20% fall in FEV1 (PD20), or to measure PEF at two hourly intervals during waking hours for one week. Skin tests with common allergens were performed and a smoking history obtained. PEF variability was expressed as the amplitude % mean (highest - lowest x 100/mean).

RESULTS

A total of 273 subjects (69%) collected a PEF meter but a completed record sheet was returned by only 247 (62%); this was still significantly more than the 202 subjects (54%) who attended for and successfully completed a challenge test. Amplitude % mean was higher in women than in men (9.7% v 8.5%). In multiple regression analysis amplitude % mean increased significantly with age, mean skin weal diameter, and with current smoking. The odds of having a PD20 below 24.5 mumol increased with mean skin weal diameter and were greater in current smokers. Neither age nor sex had a significant effect on bronchial reactivity but there were significant interactions between age and the effects of both smoking and atopy.

CONCLUSIONS

The higher response rate associated with the use of PEF variability measurement, and the association with factors implicated in the pathogenesis of airways disease, suggest that PEF variability would be a useful measurement to employ in epidemiological studies.