Cutaneous Melanoma and Sentinel Lymph Node Biopsy; An Epidemiology Study of Population Level Data

Aims Cutaneous melanoma accounts for 90% of all melanoma cases diagnosed. In addition, the incidence of cutaneous melanoma is increasing by approximately 3-7% yearly, and it is the most rapidly increasing cancer diagnosed in white populations worldwide. The aim of this study is to assess the survival benefit of Sentinel Lymph Node Biopsy (SLNB) in cutaneous melanoma in an Irish population. Methods Population based data was obtained from the National Cancer Registry of Ireland (NCRI) on all patients with a cutaneous melanoma diagnosed over a 20-year period 1994-2014 and predictors of Overall Survival (OS) were assessed. Results 13302 patients were identified with a melanoma diagnosis between 1994-2014. OS varied with gender, age, smoking and marital status, anatomical location and TMN stage. 2196 (17%) patients underwent SLNB, which included 710 patients in the stage 1 melanoma category (<11% of this group). Undergoing a SLNB was not an independent predictor of improved OS (p=0.440). However, a positive SLNB result was an independent predictor of OS (0.001). Conclusion This Irish population-based data re-affirms demographic indicators of poorer survival. A positive SLNB result indicates poorer survival; however, the precedent itself is not a predictor of OS.

The Early Impact of COVID-19 on Urological Service Provision

Aim COVID-19 has posed an unprecedented challenge to healthcare systems. We aimed to observe the impact on urological care delivery in an Irish university hospital. Methods Data on urological activity was prospectively collected for 3 months from March 2020. A retrospective review of the same period in 2019 was performed for control data. Results Over the 2020 study period, 356 urological admissions were recorded; a 23.1% decrease from the 2019 corresponding period(n=463). A 21.7% decrease in flexible cystoscopies was seen (162 versus 207). 125 theatre cases (36 off-site) were performed in the 2020 period, versus 151 in 2019. Emergency case load remained stable, with 69 cases in the 2020 period. The percentage of trainee-performed cases was preserved. COVID-era outpatient activity increased, to involve 559 clinic consultations compared to 439 the preceding year; a reflection of annual growth in service demand and facilitated by virtual clinic application (n=403). There were 490 instances of patients cancelling/failing to attend outpatient appointments, compared to 335 in 2019. Conclusion The Irish COVID-19 outbreak has created obstacles for urological care. Nonetheless, urgent/emergent urological cases persist. Our unit has managed this to-date with flexible adaptation of service delivery. The global challenge posed by COVID-19 will demand ongoing resourcefulness to minimise impact on patients with time-sensitive urological conditions.

Cyclosporine metabolism and pharmacokinetics following intravenous and oral administration in the dog

The influence of assay method on single dose cyclosporine (CsA) pharmacokinetics was studied in nine dogs receiving either i.v. or oral CsA. Samples were drawn from hepatic, portal, and systemic veins at various times after the dose and CsA levels were determined by radioimmunoassay (RIA) and high-performance liquid chromatography (HPLC). Blood concentration-time data were analyzed by nonlinear least-squares regression, using two-compartment models. RIA/HPLC ratios for all samples were greater than one, and did not change significantly over time. The mean RIA/HPLC ratios for samples drawn from all three veins were higher after oral than i.v. doses of the drug (P less than 0.05). Area under the concentration-time curve (AUC) was higher and systemic clearance (CIs) lower than calculated on the basis of RIA results, regardless of the route of administration. AUC calculated for CsA metabolites (RIA-HPLC) was highest in the portal vein after an oral dose of CsA. Bioavailability was 20.4% and 27.0% when estimated using HPLC and RIA data, respectively. The mean CsA metabolite index (CMI), when calculated for hepatic, portal, or systemic vein, was greater when the drug was administered orally. The mean hepatic extraction ratio (HER) of the parent drug and for CsA metabolites was approximately 23% in i.v. and p.o. studies. These results suggest that the gastrointestinal tract may play a role in the metabolism of CsA when the drug is administered orally. In addition, if CsA metabolites not measured by HPLC have either toxic or immunosuppressive properties, the RIA assay may be more useful for monitoring patients.

Alterations in the tRNA's of Escherichia coli recovered from lethally infected animals

Escherichia coli grown in chemically defined iron-deficient media or in fluids containing the iron-binding proteins transferrin, lactoferrin, or ovotransferrin have well-characterized alterations in the chromatographic properties of tRNA's containing the modified nucleoside 2-methylthio-N6-(delta2-isopentenyl)-adenosine. The present work shows that similar tRNA alterations occur in E. coli O111 recovered from the peritoneal cavities of lethally infected guinea pigs and rabbits. Adding iron to these in vivo-grown bacteria resulted in the rapid conversion of chromatographically abnormal tRNA's to the normal species. The work strongly suggests that host iron-binding proteins, present in mucosal and other secretions, can affect the metabolism of invading organisms. The idea that the tRNA alterations are connected with the adaptation of E. coli to growth under the iron restricted conditions imposed by iron-binding proteins in tissue fluids, and thus with bacterial pathogenicity, is therefore made particularly attractive.