Dose to patients through nuclear medicine procedures in a department in northern Greece

Diagnostic nuclear medicine procedures in a large hospital in northern Greece during 1984–1988 have been surveyed in order to estimate the radiation burden to the patients. The mean effective dose equivalent (EDE) was found to be 1.96 mSv/examination and 2.46 mSv/patient, allowing for the fact that a number of patients underwent more than one examination. Apart from EDE, absorbed dose has been calculated for bone marrow, thyroid, gonads, kidneys and bladder. Patients undergoing multiple examinations have been used to calculate true patient dose distribution as well as patient time-weighted dose distribution. Because of the predominance of renal examinations, 8.5 fatal renal malignancies are expected per 100000 patients.     

Laparoscopic Cholecystectomy in Obese and Nonobese Patients

Background: From November 1997 to November 1998, 145 cases of laparoscopic cholecystectomy (LC) have been attempted at the District General Hospital of Corfu. Methods: 23 (15.8%) were obese (Group I, BMI >30) and 122 (84.2%) were nonobese patients (Group II, BMI ≤30). One-fifth of these patients suffered from acute cholecystitis. Results: Operative time averaged 95 minutes in Group 1 and 78 minutes in Group II. There were no deaths. There were no significant differences between the obese and nonobese groups in conversion to open procedure (Group1: 0%, Group II: 2.4%), intraoperative and postoperative complications (Group I: 4.3%, Group II: 4.0%), operating time, and length of postoperative hospitalization. Conclusion: LC was a safe and effective treatment for obese patients with symptomatic cholelithiasis.     

Initial experience of three-minute freeze cycles using the second-generation cryoballoon ablation: acute and short-term procedural outcomes

Background

The second-generation cryoballoon (CB-A) (Arctic Front Advance, Cryocath, Medtronic, MN, USA) might significantly improve procedural outcome with respect to the first-generation balloon. These technological improvements might also question the current recommendation of the need a 4-min freeze to achieve durable pulmonary vein isolation (PVI).

Objective

The main aim of the study was to analyze the procedural efficacy of a 3-min freeze–thaw cycles with the CB-A balloon in the terms of rates of acute PVI and 6-month outcome.

Methods

Patients having undergone CB-A for PAF or early persistent AF, with 3-min freeze–thaw cycles were consecutively included in our analysis. Acute procedural success was measured in terms of the rate of PVI. Short-term follow-up was evaluated by the means of 24-h Holters and clinical examinations at regular intervals.

Results

Fifty-two consecutive patients (35 male (67 %); mean age, 59.8?±?10.5) were included. Mean procedure and fluoroscopy times were 96?±?15 and 13.2?±?8.3 min, respectively. Mean time from groin puncture to catheter extraction was 60.4?±?20 min. After a mean of 1.5 freeze cycles per vein of 3 min in duration, all 208 (100 %) PVs could be isolated with the CB-A. A total 192 (91 %) veins were isolated during the first freeze. At a mean of 5.7-month follow-up, 82 % of patients were free of AF.

Conclusion

CB-A is effective in producing PVI by using 3-min-duration freeze cycles. After a mean of 1.5 freeze per vein, freedom from AF was achieved in 82 % of patients at 6-month follow-up.     

Volumetric tomography of fluorescent proteins through small animals in vivo

Volumetric detection and accurate quantification of fluorescent proteins in entire animals would greatly enhance our ability to monitor biological processes in vivo. Here we present a quantitative tomographic technique for visualization of superficial and deep-seated (>2-3 mm) fluorescent protein activity in vivo. We demonstrate noninvasive imaging of lung tumor progression in a murine model, as well as imaging of gene delivery using a herpes virus vector. This technology can significantly improve imaging capacity over the current state of the art and should find wide in vivo imaging applications in drug discovery, immunology, and cancer research.     

Pediatric surgery during the COVID-19 pandemic

The coronavirus disease 2019 (COVID-19) pandemic has had a major impact on pediatric surgery. The infection is often asymptomatic and atypical in children, while overlapping presentations with other infectious diseases generate additional diagnostic challenges. The high probability of missed pediatric cases and the invasive nature of surgery generate great concern for widespread transmission in this setting. Current guidelines suggest that triage of cases should be made on a case-by-case basis by a multidisciplinary team of experts. Decision-making can be assisted by classifying cases as elective, urgent, or an emergency according to the risks of delaying their surgical management. A workflow diagram should ideally guide the management of all cases from admission to discharge. When surgery is necessary, all staff should use appropriate personal protective equipment, and high-risk practices, such as aerosol-generating tools or procedures, should be avoided if possible. Furthermore, carefully designed organizational protocols should be established to minimize transmission while ensuring the uninterrupted operation of pediatric surgery units. For example, surgical teams can be divided into small weekly rotating groups, and healthcare workers should be continuously monitored for COVID-19 symptoms. Additionally, team protocols in the operating room can optimize communication and improve adherence to personal protective equipment use. Isolated operating rooms, pediatric intensive care units, and surgical wards should be specifically designed for suspected or confirmed COVID-19 cases. Finally, transportation of patients should be minimal and follow designated short routes. All these measures can help mitigate the effects of the COVID-19 pandemic on pediatric surgery units.     

Preconditioning enhances the expression of mitochondrial antioxidant thioredoxin-2 in the forebrain of rats exposed to severe hypobaric hypoxia

The impact of severe hypoxia and preconditioning on the expression of the mitochondrial antioxidant thioredoxin-2 (Trx-2) in rat hippocampus (CA1, CA2, CA3 fields, and dentate gyrus) and neocortex was studied by immunocytochemistry. The preconditioning consisted of three trials of mild hypobaric hypoxia (360 Torr, 2 hr) spaced at 24 hr. The last trial was followed by severe hypobaric hypoxia (180 Torr, 3 hr) 24 hr later. Both in hippocampus and in neocortex, severe hypobaric hypoxia resulted in enhanced Trx-2 expression at 3 hr, followed by a slight decline in Trx-2 levels, which nevertheless remained increased at 24 hr elsewhere except for the CA1 region. The preconditioning considerably augmented severe hypoxia-induced Trx-2 immunoreactivity, affecting both the number of immunoreactive cells and the intensity of immunostaining. The findings suggest a role for Trx-2 in the formation of brain hypoxic/ischemic tolerance accomplished by the preconditioning.     

Endothelin-B receptors and ventricular arrhythmogenesis in the rat model of acute myocardial infarction

The arrhythmogenic effects of endothelin-1 (ET-1) are mediated via ETA-receptors, but the role of ETB-receptors is unclear. We examined the pathophysiologic role of ETB-receptors on ventricular tachyarrhythmias (VT/VF) during myocardial infarction (MI). MI was induced by coronary ligation in two animal groups, namely in wild-type (n = 63) and in ETB-receptor-deficient (n = 61) rats. Using a telemetry recorder, VT/VF episodes were evaluated during phase I (the 1st hour) and phase II (2–24 h) post-MI, with and without prior β-blockade. Action potential duration at 90% repolarization (APD90) was measured from monophasic epicardial recordings and indices of sympathetic activation were assessed using fast-Fourier analysis of heart rate variability. Serum epinephrine and norepinephrine were measured with radioimmunoassay. MI size was similar in the two groups. There was a marked temporal variation in VT/VF duration; during phase I, it was higher (p = 0.0087) in ETB-deficient (1,519 ± 421 s) than in wild-type (190 ± 34 s) rats, but tended (p = 0.086) to be lower in ETB-deficient (4.2 ± 2.0 s) than in wild-type (27.7 ± 8.0 s) rats during phase II. Overall, the severity of VT/VF was greater in ETB-deficient rats, evidenced by higher (p = 0.0058) mortality (72.0% vs. 32.1%). There was a temporal variation in heart rate and in the ratio of low- to high-frequency spectra, being higher (<0.001) during phase I, but lower (p < 0.05) during phase II in ETB-deficient rats. Likewise, 1 h post-MI, serum epinephrine (p = 0.025) and norepinephrine (p < 0.0001) were higher in ETB-deficient (4.20 ± 0.54, 14.24 ± 1.39 ng/ml) than in wild-type (2.30 ± 0.59, 5.26 ± 0.67 ng/ml) rats, respectively. After β-blockade, VT/VF episodes and mortality were similar in the two groups. The ETB-receptor decreases sympathetic activation and arrhythmogenesis during the early phase of MI, but these effects diminish during evolving MI.