Monitoring SARS-CoV-2 decontamination by dry heat and ultraviolet treatment with a swine coronavirus as a surrogate

The critical need for reliable methods to validate decontamination protocols for personal protective equipment (PPE) for re-use during the SARS-CoV-2 pandemic is limited by the need for specialized containment facilities to handle the virus. Hence, we have herein validated the use of a swine coronavirus as a surrogate, and tested the effectiveness of dry heat and ultraviolet (UV) rays for PPE decontamination. Exposure of experimentally contaminated N95 masks and hospital gowns to 60°C for 20 min, and UVC at 1800 mJ/cm² resulted in a 4-log reduction and inactivation of the surrogate virus. This study provides a novel alternative to validate PPE reprocessing methods.

A study to determine the sensitivity and specificity of hospital discharge diagnosis data used in the MICA study

AIMS

To determine the sensitivity and specificity of each ICD9 code for a diagnosis of definite or possible myocardial infarction (MI) from the perspective of the Myocardial Infarction Causality Study (MICA) and to use these data to estimate the likely number of MICA cases in Scotland that would be undetected were these codes omitted from the study.

SETTING

Women resident and registered with general practitioners in the Tayside region of Scotland between October 1993 and October 1995.

METHOD

All SMR1 records of Tayside hospitalizations containing ICD9 (International Classification of Diseases, ninth revision) codes for myocardial infarction (410) or possible myocardial infarction (411, 412, 413, 414, 427.4, 427.5, 786.5) were identified for women aged between 16 and 44 years between 1 October 1993 and 15 October 1995. Original case records were sought and each episode abstracted using a predefined form. Records were independently scrutinized by two consultant cardiologists blinded to the SMR1 code. Cases were categorized as definite MI, possible MI or unlikely MI. Where there was disagreement between the two cardiologists, the profiles for such events were examined by a third cardiologist who acted as the final adjudicator. The adjudicator's verdict was, in this study, considered dominant. The sensitivity, specificity and positive predictive value of each ICD9 code was determined.

RESULTS

Two hundred and fifty-three women fulfilled the SMR1 search criteria. Case records of 204 (81%) were retrieved but four case records contained no data on the admission of interest and were classified as invalid. Forty-six of the 200 remaining patients were ineligible for the MICA study leaving 154 records for evaluation. There were 12 patients who had a discharge code for MI (ICD9 410). Of these, 11 were judged as a definite MI by both cardiologists. One event (discharge code ICD9 410) was judged as 'possible' by one cardiologist and 'unlikely' by the other. The adjudicator subsequently judged this event as 'definite'. Another six events were subsequently judged as 'possible'. Thus, after adjudication, 12 cases of definite MI and six cases of 'possible' MI were identified. The sensitivity and specificity of ICD9 code 410 was 67% and 100% respectively. The positive predictive value was 100%. The sensitivity of code 411 was 5.6%. The specificity was 99% and the positive predictive value was 50%. Code 413 had a sensitivity of 5.6% with a specificity of 94% and a positive predictive value of 9.1%. Code 414 also had a sensitivity of 5.6%. The specificity was 86% and the positive predictive value was 4.5%. Code 786.5 had a sensitivity of 17%, a specificity of 23% and a positive predictive value of 2.5%. Code 427.5 failed to identify any definite or possible cases.

CONCLUSIONS

In the MICA Study, ICD9 code 410 was found to be the most robust. All 12 patients judged to have had a definite MI had the appropriate discharge code (ICD9 410). The six patients judged to have had a possible MI all had discharge codes other than that for MI (410). However, identifying these six patients required the validation of a further 160 events-giving a combined sensitivity of 33%, a specificity of 0% and a positive predictive value of only 3.8%. The use of ICD9 codes 411, 413, 414, 427.5 and 786.5 must, therefore, only be employed when circumstances fully justify the additional workload.

Bacterial contamination of fabric stethoscope covers: the velveteen rabbit of health care?

To determine if fabric stethoscope covers pose an infection control problem, we studied how they are cared for by our healthcare workers and performed microbiological investigations on 22 covers collected over a 3-week period. Our study suggests that fabric stethoscope covers represent a potential infection control problem because they are used for prolonged periods, are infrequently laundered, and are contaminated with bacteria.

The relationship between thyroxine, oestradiol, and postnatal alopecia, with relevance to women's health in general

Post-partum hair loss is possibly due to a reduction in the levels of oestradiol and thyroxine postnatally. Alopecia and/or a persistent loss of hair condition postnatally is associated with a group of symptoms (a syndrome), wherein postnatal depression is significant, as a result of physiologically inadequate levels of thyroxine (T4) and oestradiol (E2), secondary to physiological postnatal anterior pituitary dysfunction. Using this hypothesis, the author began to apply the same hypothesis to other female patients, who were not postpartum, but with similar symptomatology. The author became aware of the necessity for an adequate level of T4 to be present for correct oestrogenization to occur. He then goes on to hypothesize on the synergistic relationship that T4 and oestradiol may have in premenstrual syndrome (PMS), infertility, dysfunctional uterine bleeding, poor placental function, osteoporosis, and anorexia nervosa. He also discusses the role lowering T4 could play in the treatment of terminal cancer breast in premenopausal women.

Strain differences in neointimal hyperplasia in the rat

We performed an initial screen of 11 rat strains by use of a standard balloon injury to the left iliac artery to observe whether genetically determined differences existed in the development of neointimal hyperplasia. Neointimal hyperplasia was assayed 8 weeks after the vascular injury on coded microscopic sections. Statistically significant differences in the percentages of the vascular wall cross-sectional areas composed of intima (percentage intima) secondary to neointimal hyperplasia were noted among the different rat strains (P<0.02), with the Brown-Norway (BN), Dark Agouti, and Milan normotensive strain rats having the highest and the spontaneously hypertensive rats (SHR) having the lowest percentages of intima. In a separate experiment, F1 hybrids of SHRxBN strains and parental BN and SHR underwent the vascular injury, and the parental strains again showed a statistically significant difference from one another in the mean percentage of intima (P<0. 0001). The F1 hybrids showed an average percentage of intima intermediate between those of the parental strains. The average lumen size of the injured BN vessels were significantly smaller than that of the noninjured control vessels (P=0.044), but this significance disappeared when the circular areas of these vessels were calculated without taking neointimal growth into consideration (P=0.649). These results provide the groundwork for a genetic linkage analysis to identify the genes that influence the development of neointimal hyperplasia after vascular injury.

Cross sectional study of contribution of clinical assessment and simple cardiac investigations to diagnosis of left ventricular systolic dysfunction in patients admitted with acute dyspnoea

OBJECTIVE

To assess the comparative contribution of clinical assessment, electrocardiography, and chest radiography to the diagnosis of left ventricular systolic dysfunction in patients admitted to a general medical ward with acute dyspnoea.

DESIGN

Prospective cross sectional study.

SETTING

Acute medical admissions ward of a teaching hospital.

SUBJECTS

71 randomly selected patients admitted with acute dyspnoea.

MAIN OUTCOME MEASURES

Sensitivity and specificity of each investigation and logistic regression analysis of each variable in identifying left ventricular systolic dysfunction.

RESULTS

Clinical assessment in this cohort of patients with severe dyspnoea was generally sensitive (sensitivity 81%). Patients were divided into three groups on the basis of clinical assessment. In the first group (37 patients) the diagnosis of systolic dysfunction was clear, in the second (22) it was in doubt, and in the third (12) it was unlikely. The sensitivity of clinical assessment in identifying left ventricular systolic dysfunction was 81% and the specificity was 47%. The specificity of diagnosis was improved by electrocardiography (69%) and chest radiography (92%). Logistic regression analysis showed that isolated pulmonary crepitations were a comparatively poor predictor of left ventricular systolic dysfunction chi 2 = 10.215, P = 0.0014) but that a full clinical examination had reasonable predictive value (chi 2 = 24.82, P < 0.00001). The combination of clinical assessment and chest radiography improved the accuracy of diagnosis (chi 2 = 28.08, P < 0.00001), as did the combination of clinical assessment and electrocardiography (chi 2 = 32.41, P < 0.00001).

CONCLUSION

Clinical assessment in patients admitted with acute dyspnoea is comparatively accurate. Patients with abnormal results on chest radiography, electrocardiography, and clinical examination have a high likelihood of having left ventricular systolic dysfunction. Echocardiography contributes little more to the diagnosis in these patients and may be more efficiently directed towards patients in whom the diagnosis is still in doubt after clinical assessment, chest radiography, and electrocardiography.

Sensitivity and specificity of QTc dispersion for identification of risk of cardiac death in patients with peripheral vascular disease

OBJECTIVE

To determine whether QTc dispersion, which is easily obtained from a standard electrocardiogram, can predict those patients with peripheral vascular disease who will subsequently suffer a cardiac death, despite having no cardiac symptoms or signs.

DESIGN

Patients with peripheral vascular disease were followed up for five years after they had had coronary angiography, radionuclide ventriculography, and their QTc dispersion calculated from their 12 lead electrocardiogram.

SUBJECTS

49 such patients were then divided into three groups: survivors (34), cardiac death (12), and non-cardiac death (3).

MAIN OUTCOME MEASURE

Survival.

RESULTS

The mean (SD; range) ejection fractions were similar in all three groups: survivors 45.9 (11.0; 27.0-52.0), cardiac death 44.0 (7.90; 28.5-59.0), and non-cardiac death 45.3 (4.55; 39.0-50.0). QTc dispersion was significantly prolonged in the cardiac death group compared with in the survivors (86.3(23.9; 41.0-139) v 56.5 (25.4; 25.0-164); P = 0.002). A QTc dispersion > or = 60 ms had a 92% sensitivity and 81% specificity in predicting cardiac death, QTc dispersion in patients with diffuse coronary artery disease was significantly (P < 0.05) greater than in those with no disease or disease affecting one, two, or three vessels.

CONCLUSIONS

There is a strong link between QTc dispersion and cardiac death in patients with peripheral vascular disease. QTc dispersion may therefore be a cheap and non-invasive way of assessing the risk of cardiac death in patients with peripheral vascular disease.

Ascertainment and severity of Marfan syndrome in a Scottish population

This study in north east Scotland has shown that Marfan syndrome has a minimal birth incidence of 1:9802 live births, a minimal prevalence of 1:14217, and that 8/30 (26.7%) of cases in our series are new mutations. The calculated mutation rate is 15 +/- 6.7 x 10(-6) and there is evidence of reduced reproductive fitness.

Osteoporosis and the Marfan syndrome

Fourteen patients with Marfan syndrome, defined according to present criteria, had bone mineral content of the distal forearm measured by single photon absorptiometry. Patients were matched for age and sex with a large local group of healthy volunteers. While further work is needed with other methods of densitometry with measurements at other sites, our results provide no evidence that there is an increased incidence of osteoporosis in Marfan syndrome. Previous reports of an association were probably due to incorrect clinical diagnosis or confusion with clinically similar syndromes known to cause osteoporosis.

Thrombolytic treatment and new calcium antagonists

Images

Dose independent pharmacokinetics of mexiletine in healthy volunteers

In 12 healthy volunteers who received orally 100, 200, 300, 400 and 600 mg mexiletine at weekly intervals, the maximum plasma concentration of mexiletine and AUC increased linearly with the dose of mexiletine. Between doses there were no significant differences in the values for clearance and volume of distribution of mexiletine but there were for plasma elimination half-life. These results indicate that the kinetics of mexiletine are linear.