Psychological distress and symptom-related burnout in asthma during the COVID-19 pandemic

People with asthma may be particularly vulnerable to pandemic-related psychological distress, and research is needed to understand the impact of the coronavirus disease 19 (COVID-19) pandemic on their health and well-being. We sought to study the well-being of people with asthma relative to non-asthmatic controls during the COVID-19 pandemic. We also investigated asthma symptoms and COVID-19-related anxiety as potential mediators of distress. Participants completed self-report measures of psychological functioning, including anxiety, depression, stress, and burnout. Controlling for potential confounds, multiple-regression analyses examined differences in psychological health between people with and without asthma. Mediator analyses investigated the role of asthma symptoms and COVID-19-related anxiety in this relationship. 234 adults (111 with asthma, 123 without) participated in an online survey from July to November 2020. During this time, people with asthma reported higher levels of anxiety, perceived stress, and burnout symptoms compared to controls. Elevations in burnout symptoms were found beyond general anxiety and depression (sr2 = .03, p < .001). Reported symptoms typical in both asthma and COVID-19 partially mediated this relationship (Pm = .42, p < .05). People with asthma reported unique psychological challenges during the COVID-19 pandemic including elevated burnout symptoms. Experience of asthma symptoms played a key role in vulnerability to emotional exhaustion. Clinical implications include increased attention to asthma symptom burden within the context of heightened environmental stress and restricted healthcare access.

608 Optimising Return to Elective Total Hip Arthroplasty (THA) Following the COVID-19 Pandemic: Lessons Learned and Future Directions

Aim

COVID-19 has led to unprecedented waiting times for elective surgery. Optimising patient pathways is paramount in tackling the backlog. Length of hospital stay (LOS) is an accepted surrogate for successful elective surgery.

The aims of our study were: 1) report on changes in LOS after restarting our elective THA service; 2) identify barriers to early discharge, 3) investigate effectiveness of implemented changes.

Method

A retrospective review of consecutive patients undergoing elective THA, comparing three groups: 1) enhanced care pathway (n=96; 09/2019–12/2019); 2) COVID group (n=56; 03/2021–04/2021); 3) intervention group (n=96; 05/2021–08/2021).

Results

LOS in the enhanced care pathway group was 2.6 ±2.1 days. During initial resumption of elective operating (COVID group) the LOS was 4.8 ±4.5 days (statistically significant increase; p=0.011). Factors affecting LOS included reduced physiotherapy provision; lack of pre-operative occupational therapy review; loss of educational classes and worse pre-operative functional status.

To address these our department employed three new physiotherapists, introduced training for nursing staff and created a post-operative proforma. The LOS subsequently reduced to 3.7 ±4.6days (p=0.166).

Subgroup analysis of the intervention group showed age <75 (p<0.001) and ASA1–2 (p=0.036) were associated with reduced LOS (2.1±1.5 days). Other variables analysed did not significantly affect LOS.

Conclusions

COVID-19 has had a significant effect on LOS, which is still not reversed. For effective resumption of THA services, pre-pandemic enhanced care pathways should be reinstated. With current restrictions preventing face-to-face classes, online educational sessions could be offered. Those younger than 75 years and ASA1–2 are most likely to be discharged without delay.

DNA content equivalence in haploid and diploid maize leaves

The qPCR assay developed to differentiate haploid and diploid maize leaf samples was unsuccessful due to DNA content difference. Haploid cells are packed more closely together with less cellular expansion. Increased ploidy content (> 2 N) directly correlates with increased cell size in plants, but few studies have examined cell morphology in plants with reduced ploidy (i.e., haploids). To pioneer a scalable new ploidy test, we compared DNA content and cellular morphology of haploid and diploid maize leaves. The amount of genomic DNA recovered from standardized leaf-punch samples was equivalent between these two ploidy types, while both epidermal and mesophyll cell types were smaller in haploid plants. Pavement cells had a substantially smaller size than mesophyll cells, and this effect was more pronounced in the abaxial epidermis. Interveinal distance and guard cell size were significantly reduced in haploids, but the cell percentage comprising stomata did not change. These results confirm the direct correlation between ploidy content and cell size in plants, and suggest that reduced cell expansion predominantly explains DNA content equivalence between haploid and diploid samples, confounding efforts to develop a haploid detection method using DNA content.

Point-of-care Hepatitis C virus testing and linkage to treatment in an Australian inner-city emergency department

BACKGROUND

In Australia, Hepatitis C Virus (HCV) treatment is declining, despite broad access to direct-acting antiviral medication. People who inject drugs are proportionally over-represented in emergency department presentations. Emergency department assessment of people who have injected drugs for HCV presents an opportunity to engage this marginalised population with treatment. We describe the outcomes of risk-based screening and point-of-care anti-HCV testing for emergency department patients, and linkage to outpatient antiviral treatment.

METHODS

During the three-month study period, consecutive adult patients who presented to the emergency department during the study times were screened for risk factors and offered the OraQuick oral HCV antibody test. Those with reactive results were offered venepuncture in the emergency department for confirmatory testing and direct-acting antiviral treatment in clinic. The main outcome measures were the number and proportion of viremic participants that were linked to the hepatitis clinic, commenced treatment and achieved a sustained viral response. Secondary outcome measures were the proportion (%) of presentations screened that were oral antibody reactive, and the prevalence and type of HCV risk factors.

RESULTS

During the study period, 2408 of the 3931 (61%) presentations to the emergency department were eligible for screening. Of these 2408 patients, 1122 (47%) participated, 307 (13%) declined participation and 977 (41%) could not be approached during their time in the emergency department. Among the 1122 participants, 378 (34%) reported at least one risk factor. Subsequently, 368 (97%) of the 378 participants underwent OraQuick anti-HCV test, and 50 (14%) had a reactive result. A risk factor of ever having injected drugs was present in 44 (88%) of participants who were sero-positive. Of the 45 that had blood tested, 30 (67%) were HCV ribonucleic acid (RNA) positive. Three participants died. Of the 27 remaining participants, 10 (37%) commenced treatment and 7 of these 10 (70%) obtained a cure. There was a high rate of homelessness (24%) among anti-HCV positive participants.

CONCLUSION

Among emergency department participants with a risk factor for HCV, positive serology was common using a rapid point-of-care test. A history of injecting drug use was identified as the risk factor with highest yield for positive HCV serology, and is suitable as a single screening question. However, linkage to care post ED presentation was low in this marginalised population. There is a need for new pathways to improve the care cascade for marginalised individuals living with HCV infection.

Review article: delivering precision oncology in intermediate-stage liver cancer

BACKGROUND

Intermediate-stage hepatocellular carcinoma (HCC), for which trans-arterial chemoembolization (TACE) constitutes the standard of care, is a patient subgroup with significant heterogeneity in clinical outcome. Sources of variation relate to differences in tumour burden, hepatic reserve, ethnicity and treatment modalities. Increasing research efforts have been dedicated to minimise the clinical diversity of this patient population and enhance optimal provision of treatment.

AIM

To comprehensively review the diverse prognostic models that have been proposed to refine the prognostic prediction of patients with HCC undergoing TACE.

RESULTS

A number of prognostic algorithms (HAP, ART, ABCR score and many others) have shown potential to address the clinical heterogeneity characterising patients with intermediate-stage HCC and facilitate early identification of patients with poor prognostic features in whom alternative treatments or best supportive care might be more appropriate than TACE.

CONCLUSIONS

While an improved characterisation of intermediate-stage HCC is a highly important clinical aim, current evidence suggests that novel prognostic algorithms in this patient population may offer potential benefits but non-negligible challenges in the provision of TACE. This review summarises the currently available evidence to facilitate the development of precision oncology in intermediate-stage HCC.

On-target sorafenib toxicity predicts improved survival in hepatocellular carcinoma: a multi-centre, prospective study

BACKGROUND

Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and has high mortality despite treatment. While sorafenib has a survival benefit for patients with advanced HCC, clinical response is highly variable.

AIM

To determine whether development of sorafenib toxicity is a prognostic marker of survival in HCC.

METHODS

In this prospective multicentre cohort study, patients with advanced-stage HCC receiving sorafenib were recruited from five international specialist centres. Demographic and clinical data including development and grade of sorafenib toxicity during treatment, radiological response to sorafenib and survival time (months) were recorded prospectively.

RESULTS

A total of 634 patients with advanced-stage HCC receiving sorafenib were recruited to the study, with a median follow-up of 6692.3 person-months at risk. The majority of patients were male (81%) with Child-Pugh A stage liver disease (74%) and Barcelona Clinic Liver Cancer stage C HCC (64%). Median survival time was 8.1 months (IQR 3.8-18.6 months). 94% experienced at least one sorafenib-related toxicity: 34% diarrhoea, 16% hypertension and 37% hand-foot syndrome (HFS). Twenty-one per cent ceased sorafenib due to toxicity and 59% ceased treatment due to progressive disease or death. On multivariate analysis, sorafenib-related diarrhoea (HR 0.76, 95% CI 0.61-0.95, P = 0.017), hypertension (HR 0.531, 95% CI 0.37-0.76, P < 0.0001) and HFS (HR 0.65, 95% CI 0.51-0.81, P < 0.0001) were all significant independent predictors of overall survival after adjusting for age, severity of liver disease, tumour stage and sorafenib dose.

CONCLUSION

Development of sorafenib-related toxicity including diarrhoea, hypertension and hand-foot syndrome is associated with prolonged overall survival in patients with advanced-stage HCC on sorafenib.

The genomic architecture of resistance to Campylobacter jejuni intestinal colonisation in chickens

BACKGROUND

Campylobacter is the leading cause of foodborne diarrhoeal illness in humans and is mostly acquired from consumption or handling of contaminated poultry meat. In the absence of effective licensed vaccines and inhibitors, selection for chickens with increased resistance to Campylobacter could potentially reduce its subsequent entry into the food chain. Campylobacter intestinal colonisation levels are influenced by the host genetics of the chicken. In the present study, two chicken populations were used to investigate the genetic architecture of avian resistance to colonisation: (i) a back-cross of two White Leghorn derived inbred lines [(61 x N) x N] known to differ in resistance to Campylobacter colonisation and (ii) a 9(th) generation advanced intercross (61 x N) line.

RESULTS

The level of colonisation with Campylobacter jejuni following experimental infection was found to be a quantitative trait. A back-cross experiment using 1,243 fully informative single nucleotide polymorphism (SNP) markers revealed quantitative trait loci (QTL) on chromosomes 7, 11 and 14. In the advanced intercross line study, the location of the QTL on chromosome 14 was confirmed and refined and two new QTLs were identified located on chromosomes 4 and 16. Pathway and re-sequencing data analysis of the genes located in the QTL candidate regions identified potential pathways, networks and candidate resistance genes. Finally, gene expression analyses were performed for some of the candidate resistance genes to support the results.

CONCLUSION

Campylobacter resistance in chickens is a complex trait, possibly involving the Major Histocompatibility Complex, innate and adaptive immune responses, cadherins and other factors. Two of the QTLs for Campylobacter resistance are co-located with Salmonella resistance loci, indicating that it may be possible to breed simultaneously for enhanced resistance to both zoonoses.

Prevention of materno-foetal transmission of hepatitis B in sub-Saharan Africa: the evidence, current practice and future challenges

Hepatitis B (HBV) infection is highly endemic in sub-Saharan Africa (SSA), where more than 8% of the population remain chronic HBV carriers. SSA has one of the highest HBV-related liver cancer rates in the world (CA Cancer J Clin, 55, 2005, 74) and HBV-related liver cancer is the most common cause of premature death in West Africa (Lancet Oncol, 9, 2008, 683; Hepatology, 39, 2004, 211). As such, HBV represents a significant global threat to health in the African continent. Most SSA countries have elected to vaccinate all children against HBV through the WHO-sponsored Expanded Program of Immunization and the current recommendation from WHO-AFRO is for birth-dose HBV vaccination to prevent maternal/child transmission (MFT) and early horizontal transmission of HBV. However, in Africa, HBV vaccine coverage remains low and HBV birth-dose vaccination has not been implemented. HBV transmission from mother to child in the early perinatal period therefore remains a significant contributor to the burden of HBV-related disease in SSA. This review explores the evidence for materno-foetal transmission of HBV in SSA, outlining current practice for HBV MFT prevention and identifying the significant challenges to implementation of HBV prevention in SSA.

Hepatitis C recurrence: the Achilles heel of liver transplantation

Hepatitis C virus (HCV) infection is the most common indication for liver transplantation worldwide; however, recurrence post transplant is almost universal and follows an accelerated course. Around 30% of patients develop aggressive HCV recurrence, leading to rapid fibrosis progression (RFP) and culminating in liver failure and either death or retransplantation. Despite many advances in our knowledge of clinical risks for HCV RFP, we are still unable to accurately predict those most at risk of adverse outcomes, and no clear consensus exists on the best approach to management. This review presents a critical overview of clinical factors shown to influence the course of HCV recurrence post transplant, with particular focus on recent data identifying the important role of metabolic factors, such as insulin resistance, in HCV recurrence. Emerging data for genetic markers of HCV recurrence and their usefulness for predicting adverse outcomes will also be explored.

Nursing the tropics: nurses as agents of imperial hygiene

BACKGROUND

Mrs Francis Piggott proposed the Colonial Nursing Association in 1895 as a means of supplying Britain's colonies and dominions with trained professional nurses, who would support the health of white colonists abroad. Over 8400 nurses were placed between 1896 and the Association's end in 1966. Despite the burgeoning of scholarship on gender and empire over the last few decades, there is still more research to be done examining nurses as professional, working women, who present a fascinating variation on the figure of the woman traveler.

METHODS

This essay focuses on 1896-1927, exploring how nurses were prepared for their labor abroad and how these skills were challenged and adapted within a foreign environment. We contextualize this discussion with examples from literary tales of exploration and adventure and discourses of empire.

RESULTS/CONCLUSIONS

Though the sources of disease against which nurses fought changed during this period, we assert that the underlying role of the nurse continued the same: she was meant to use the tools of personal as well as public 'hygiene' to create both physical and cultural boundaries around her white patients and herself, setting colonists apart from their colonial setting.

Identifying the superior measure of rapid fibrosis for predicting premature cirrhosis after liver transplantation for hepatitis C

BACKGROUND

Hepatitis C virus (HCV) recurrence post liver transplant is universal, with a subgroup of patients developing rapid hepatic fibrosis. Various clinical definitions of rapid fibrosis (RF) have been used to identify risks for rapid progression, but their comparability and efficacy at predicting adverse outcomes has not been determined.

METHODS

Retrospective data analysis was conducted on 100 adult patients with HCV who underwent liver transplantation at a single center. We measured year 1 fibrosis progression (RF defined as METAVIR F score ≥ 1 at 1-year liver biopsy), time to METAVIR F2-stage fibrosis, and fibrosis rate (calculated using liver biopsies graded by METAVIR scoring F0-4; fibrosis rate = fibrosis stage/year post transplant). RF was defined as ≥ 0.5 units/year.

RESULTS

Multivariate analysis revealed that donor age and peak HCV viral load were significant risks for RF, when fibrosis rate was used to define RF. Advanced donor age was a risk for rapid progression to F2-stage fibrosis, whereas genotype 2 or 3 HCV infection was protective. Fibrosis rate had the strongest correlation with time to cirrhosis development (P < 0.0001, r = -0.76) and was the most accurate predictor of rapid graft cirrhosis (P < 0.0001, area under the curve 0.979, sensitivity 100%, specificity 94%).

CONCLUSION

Different measures of RF progression identify different risks for RF and are not directly comparable. Fibrosis rate was the most accurate predictor of rapid graft cirrhosis.

Toll-like receptor 3 and 7/8 function is impaired in hepatitis C rapid fibrosis progression post-liver transplantation

Recurrence of hepatitis C (HCV) postliver transplant is universal, with a subgroup developing rapid hepatic fibrosis. Toll-like receptors (TLRs) are critical to innate antiviral responses and HCV alters TLR function to evade immune clearance. Whether TLRs play a role in rapid HCV recurrence posttransplant is unknown. We stimulated peripheral blood mononuclear cells (PBMCs) from 70 patients with HCV postliver transplant with TLR subclass-specific ligands and measured cytokine production, TLR expression and NK cell function. Rate of fibrosis progression was calculated using posttransplant liver biopsies graded by Metavir scoring (F0-4; R=fibrosis stage/year posttransplant; rapid fibrosis defined as >0.4 units/year). Thirty of 70 (43%) patients had rapid fibrosis progression. PBMCs from HCV rapid-fibrosers produced less IFNα with TLR7/8 stimulation (p=0.039), less IL-6 at baseline (p=0.027) and with TLR3 stimulation (p=0.008) and had lower TLR3-mediated monocyte IL-6 production (p=0.028) compared with HCV slow fibrosers. TLR7/8-mediated NKCD56 dim cell secretion of IFNγ was impaired in HCV rapid fibrosis (p=0.006) independently of IFNα secretion and TLR7/8 expression, while cytotoxicity remained preserved. Impaired TLR3 and TLR7/8-mediated cytokine responses may contribute to aggressive HCV recurrence postliver transplantation through impaired immune control of HCV and subsequent activation of fibrogenesis.

Toll-like receptor 3 and 7/8 function is impaired in hepatitis C rapid fibrosis progression post-liver transplantation

Recurrence of hepatitis C (HCV) postliver transplant is universal, with a subgroup developing rapid hepatic fibrosis. Toll-like receptors (TLRs) are critical to innate antiviral responses and HCV alters TLR function to evade immune clearance. Whether TLRs play a role in rapid HCV recurrence posttransplant is unknown. We stimulated peripheral blood mononuclear cells (PBMCs) from 70 patients with HCV postliver transplant with TLR subclass-specific ligands and measured cytokine production, TLR expression and NK cell function. Rate of fibrosis progression was calculated using posttransplant liver biopsies graded by Metavir scoring (F0-4; R=fibrosis stage/year posttransplant; rapid fibrosis defined as >0.4 units/year). Thirty of 70 (43%) patients had rapid fibrosis progression. PBMCs from HCV rapid-fibrosers produced less IFNα with TLR7/8 stimulation (p=0.039), less IL-6 at baseline (p=0.027) and with TLR3 stimulation (p=0.008) and had lower TLR3-mediated monocyte IL-6 production (p=0.028) compared with HCV slow fibrosers. TLR7/8-mediated NKCD56 dim cell secretion of IFNγ was impaired in HCV rapid fibrosis (p=0.006) independently of IFNα secretion and TLR7/8 expression, while cytotoxicity remained preserved. Impaired TLR3 and TLR7/8-mediated cytokine responses may contribute to aggressive HCV recurrence postliver transplantation through impaired immune control of HCV and subsequent activation of fibrogenesis.

Type 2 diabetes does not worsen prognosis in hepatocellular carcinoma

INTRODUCTION

Type 2 diabetes (T2DM) is associated with liver inflammation and carcinogenesis. The prevalence of T2DM among patients with liver cirrhosis and hepatocellular carcinoma is increasing. However, the effect of T2DM on the natural history of hepatocellular carcinoma is not known.

AIM

To examine the effect of T2DM on hepatocellular carcinoma (HCC) survival in treated and untreated disease.

METHODS

Retrospective analysis was performed on HCC cases diagnosed during 2000-2005, and prospectively during 2006-August 2007. Demographics, HCC staging, response to treatment, and survival were collected. A comparison was made between patients with T2DM and without T2DM.

RESULTS

One hundred and thirty-five patients were recruited in total; 58 (43%) had T2DM. Seventy (37 diabetic) patients were treated with percutaneous radiological therapies, with 168 treatments given. Treatment was determined by AASLD guidelines and patient tolerance, there was no randomisation. There was no significant difference in survival between diabetic and nondiabetic patients. There was a nonsignificant trend towards greater survival in diabetic patients (overall median survival diabetics 21 mths vs nondiabetics 5 mths, P=0.355).

CONCLUSIONS

T2DM does not negatively impact on the natural history of treated or untreated HCC.

Ethics and opportunity costs: have NICE grasped the ethics of priority setting?

The Social Value Judgments consultation document reveals NICE's failure to understand its role in healthcare prioritisation

Faecal calprotectin in the assessment of Crohn's disease activity

BACKGROUND

Clinical and laboratory assessment of activity in Crohn's disease (CD) correlate poorly with endoscopic findings. Calprotectin is a calcium-binding protein abundant in neutrophil cytosol, and extremely stable in faeces. Faecal calprotectin (FC) is an excellent surrogate marker of neutrophil influx into the bowel lumen.

AIM

To assess whether FC concentration from a spot stool sample reliably detects active inflammation in patients with CD.

DESIGN

Cross-sectional comparative study.

METHODS

Subjects had a previously confirmed diagnosis of CD and were suspected on clinical grounds to be in the midst of a relapse. Thirty-five entered the study; they underwent radiolabelled white cell scanning (WCS) and had a stool sample collected for calprotectin measurement on the same day. A Crohn's disease activity index (CDAI) was also calculated for each. The WCS scans were scored at six standard sites to give a mean total, 'extent', 'severity' and 'combined extent and severity' scores.

RESULTS

FC was significantly and positively correlated with mean total (r = 0.73, p < 0.001), 'extent' (r = 0.71, p < 0.001), 'severity' (r = 0.64, p < 0.001) and combined 'extent and severity' WCS scores (r = 0.71, p < 0.001). A cut-off of faecal calprotectin > 100 microg/g gave a sensitivity of 80%, specificity of 67%, positive predictive value of 87% and a negative predictive value of 64% in identifying those with and without any inflammation on WCS. There was, however, no significant correlation between CDAI and mean total WCS score (r = 0.21, p = 0.24), nor between CDAI and FC (r = 0.33, p = 0.06).

DISCUSSION

While the CDAI does not accurately reflect inflammatory activity in CD, a one-off FC reliably detects the presence or absence of intestinal inflammation in adult patients with CD, compared to WCS.

Embolus of surgical adhesive to the extremities causing acute ischemia: Report of two cases

We present 2 cases in which a surgical adhesive embolized to the extremities. In the first case an adhesive was successfully used in the repair of a DeBakey type I aortic dissection. The patient was seen 2 months postoperatively with acute lower extremity ischemia, and a large piece of adhesive was extracted from the iliac and femoral arteries at embolectomy. In the second case the adhesive was used to seal a pericardial patch during repair of a ventricular septal defect. This patient was seen 1 day postoperatively with acute arm ischemia, and the adhesive particle was extracted from the brachial artery during embolectomy.

Pharmacologic insights into the future of trastuzumab

A combination of factors has been responsible for improvements in cancer survival and cure rates. In addition to new therapies with novel/genetic targets, these include improvements in drug delivery, new schedules/sequencing of drug administration and the identification of combination therapies with greater activity/dose density than existing regimens. The recognition that such criteria can affect treatment outcome has led to their incorporation into clinical trials of new drugs. Furthermore, pharmacokinetic and pharmacodynamic parameters have become increasingly important for the rational selection of dose, administration route and schedule. The humanized monoclonal antibody trastuzumab (Herceptin) has been rationally developed to target the human epidermal growth factor receptor-2 (HER2), which is overexpressed in 20%-30% of breast cancers and is associated with poor prognosis. Trastuzumab when administered i.v. on a weekly schedule either alone or in combination with taxanes, improves survival of women with HER2-positive metastatic breast cancer. Based upon pharmacokinetic considerations, current studies are examining whether trastuzumab can be administered i.v. every three weeks or by the s.c. route. These regimens would have advantages for patients and medical staff in terms of acceptability, ease of administration and, potentially, cost effectiveness. Furthermore, various combinations of trastuzumab and chemotherapeutic agents are being explored with the aim of identifying the optimal combination regimen for clinical use. The rationale for these various studies and the studies themselves are described.

Pain on injection of prilocaine plain vs. lidocaine with epinephrine. A prospective double-blind study

BACKGROUND

Prilocaine has been described as causing less pain on injection than lidocaine with epinephrine, possibly because of the higher pH of the prilocaine anesthetic solution.

METHODS

Three hundred ten consecutively seen patients in a general practice received a total of 334 maxillary buccal infiltration or inferior alveolar block injections, administered under clinical conditions by one of two dentists. Immediately afterward, patients rated the pain from each injection on a six-point scale. Twenty of these patients (in 21 separate appointments) received, and were asked to rate the pain associated with, a second injection of a contralateral tooth. The authors analyzed the pain response by operator, location of injection, patient's age, patient's sex and anesthetic.

RESULTS

The difference in perceived pain between lidocaine and prilocaine was not statistically significant. Regardless of the anesthetic used, the perceived pain was usually no more than mild. Of 334 injections, 292 (87 percent) were rated as causing either no pain or mild pain.

CONCLUSIONS

Under clinical conditions, there is no statistically significant difference between injection pain associated with prilocaine plain vs. that associated with lidocaine with 1:100,000 epinephrine.

CLINICAL IMPLICATIONS

Since there is no significant difference in associated pain on injection between prilocaine plain and lidocaine with 1:100,000 epinephrine, dentists may prefer lidocaine with epinephrine. Since there is less anesthetic in each cartridge of lidocaine, it may require the use of less anesthetic per patient, and the vasoconstrictor can prolong its duration.

Bacterial counts in experimental, contaminated crush wounds irrigated with various concentrations of cefazolin and penicillin

The objective of this study was to determine if three different concentrations of cefazolin and penicillin irrigation solutions reduce quantitative bacterial counts in experimental crush wounds contaminated with multiple species of bacteria. The design used was a randomized, blinded, experimental animal study. An animal bite wound model was created by innoculating crushed incisions with three species of bacteria. Four paravertebral incisions extending to deep fascia were created in each of twelve anesthetized albino guinea pigs. Wound edges were clamped with a hemostat for five seconds to create crushed, devitalized tissue within each wound. Wounds were inoculated with 0.4 mL of a standard solution of Staphylococcus aureus, Bacterioides fragilis, and Pasturella multocida and covered. Four hours after inoculation, each wound was scrubbed for 30 seconds with 20% poloxamer 188 and then irrigated with 100 mL of one of four solutions: normal saline solution (control); cefazolin (CZ) 2 mg/mL, plus penicillin G (PCN) 200 units/mL (low dose); CZ 10 mg/mL, plus PCN 2,000 units/mL (intermediate dose); and CZ 50 mg/mL, plus PCN 20, 000 units/mL (high dose). Investigators were blinded to the solutions used. Wounds were covered with a vapor-permeable dressing. Six days after treatment, each wound was examined for signs of infection and then excised for quantitative bacteriologic analysis. Colony counts were reported as counts per gram of tissue. Wounds in the four irrigation solution groups were compared using ANOVA. A log difference of 3 was considered significant. The average log total bacteria/gram tissue for the four groups were: control, 4.35 (95% CI; 1.01); low dose, 4.09 (95% CI; 1.42); intermediate dose, 4.47 (95% CI; 1.27); and high dose, 3.45 (95% CI; 1.33). No wounds in the high-dose group had any clinical signs of infection, whereas 50% of wounds in the intermediate dose group, 42% in the low dose group, and 33% in the control group had either erythema, induration, or purulence. There were no statistically significant differences in the bacterial counts/gram tissue or clinical infection rates in any of the groups. A formal trend analysis failed to find a significant linear trend for decreasing bacterial counts for either antibiotic. In this experimental bite wound model containing contaminated, crushed tissue, irrigation with various solutions of cefazolin plus penicillin G did not reduce quantitative bacterial counts more than 3.1 log total bacteria/gram tissue.

Regioselective enzymatic aminoacylation of lobucavir to give an intermediate for lobucavir prodrug

Synthesis of lobucavir prodrug, L-valine, [(1S,2R,3R)-3-(2-amino-1,6-dihydro-6-oxo-9H-purin-9-yl)-2-(hydroxymethyl) cyclobutyl]methyl ester monohydrochloride (BMS 233866), requires regioselective coupling of one of the two hydroxyl groups of lobucavir (BMS 180194) with valine. Either hydroxyl group of lobucavir could be selectively aminoacylated with valine by using enzymatic reactions. N-[(Phenylmethoxy)carbonyl]-L-valine, [(1R,2R,4S)-2-(2-amino-6-oxo-1H-purin-9-yl)-4-(hydroxymethyl)cyclobutyl]methyl ester (3, 82.5% yield), was obtained by selective hydrolysis of N,N'-bis[(phenylmethoxy)carbonyl]bis[L-valine], O,O'-[(1S,2R,3R)-3-(2-amino-6-oxo-1H-purin-9-yl)cyclobuta-1,2-diyl]methyl ester (1) with lipase M, and L-valine, [(1R,2R,4S)-2-(2-amino-1,6-dihydro-6-oxo-9H-purin-9-yl)-4-(hydroxymethyl)cyclobutyl]methyl ester monohydrochloride (4, 87% yield) was obtained by hydrolysis of bis[L-valine], O,O'-[(1S,2R,3R)-3-(2-amino-6-oxo-1H-purin-9-yl)cyclobuta-1,2-diyl]methyl ester, dihydrochloride (2), with lipase from Candida cylindracea. The final intermediate for lobucavir prodrug, N-[(phenylmethoxy)carbonyl]-L-valine, [(1S,2R,4R)-3-(2-amino-6-oxo-1H-purin-9-yl)-2-(hydroxymethyl)cyclobutyl]methyl ester (5), could be obtained by transesterification of lobucavir using ChiroCLEC BL (61% yield), or more selectively by using immobilized lipase from Pseudomonas cepacia (84% yield).