An improved model for the measurement of myocardial perfusion in human beings using N-13 ammonia

BACKGROUND: Oxygen 15 water and nitrogen 13 ammonia are widely used for the quantitative measurement of myocardial perfusion with positron emission tomography. However, blood flow obtained with N-13 ammonia by use of the conventional 2-compartment model frequently underestimates flow by 30% to 50% compared with O-15 water. We hypothesized that this discrepancy is a result of the model configuration of N-13 ammonia and investigated changes to the mathematical model to determine whether more accurate measurements of perfusion could be obtained. METHODS AND RESULTS: Twelve healthy volunteers were sequentially studied with O-15 water and N-13 ammonia at rest and during maximal coronary vasodilation with adenosine. Perfusion measurements obtained with the conventional and modified models were compared with values obtained with O-15 water. The conventional N-13 ammonia model underestimated flow by 37% +/- 16% at rest and by 20% +/- 24% with stress when compared with flows obtained with O-15 water. The modified model yielded flow values closer to the line of identity than the conventional model (y = 1.07x + 0.04 vs y = 0.69x + 0.08; respectively; P < .01). CONCLUSIONS: Model changes made N-13 ammonia myocardial blood flow estimates more comparable to those obtained with O-15 and may allow for better comparison of flows obtained with these two tracers in the future. Further efforts are warranted to evaluate the accuracy of flow models in human subjects.     

Prospective evaluation of the sensitivity of physical examination in chest trauma

BACKGROUND: Chest radiographs are routine for patients presenting with blunt and penetrating chest trauma. The accuracy of physical examination in the diagnosis of hemopneumothorax in these patients is unclear. A prospective study was performed to define the utility of routine portable chest radiographs in 676 trauma patients. METHODS: Over 19 months (January 2000-July 2001), 676 patients who presented with penetrating or blunt chest trauma were interviewed and examined for signs and symptoms of hemopneumothorax. The incidence of chest pain or tenderness and tachypnea was noted and both lung fields were auscultated. A portable chest radiograph was then performed on all the patients. RESULTS: All the patients were hemodynamically stable. Five hundred twenty-three patients sustained blunt trauma, with seven hemopneumothoraces (1.3%). The negative predictive values of auscultation, pain or tenderness, and tachypnea were 99& to 100%. One hundred fifty-three patients sustained penetrating chest trauma. Of these injuries, 68 were gunshot wounds and 85 were stab wounds. Twenty-four (16%) of these patients had hemopneumothoraces. The sensitivities of auscultation, pain or tenderness, and tachypnea were 50%, 25%, and 32%, respectively. The negative predictive values of these tests were < 91%. CONCLUSION: Blunt chest trauma patients who are hemodynamically stable with a normal physical examination do not require a routine chest radiograph. In contrast, all victims of penetrating trauma require chest radiographs because many will have hemopneumothorax in the absence of clinical findings.     

Notes From the Field: The Combined Effects of Tocilizumab and Remdesivir in a Patient With Severe COVID-19 and Cytokine Release Syndrome

SARS-CoV-2 is known to cause severe bilateral pneumonia and acute respiratory distress syndrome or COVID-19 in patients, which can be debilitating and even fatal. With no drugs or vaccines available yet, a wide range of treatment regimens used are being repurposed. The need of the hour is to analyze various currently available regimens and devise a treatment plan that is most effective for COVID-19. Here we describe the case of a 68-year-old man with hypertension and diabetes, exhibiting symptoms of cough and shortness of breath, who presented at the emergency department of our hospital. Chest computed tomography revealed bilateral ground glass opacities that were indicative of COVID-19, and a computed tomography score of 24 was indicative of severe pulmonary pneumonia. He tested positive for COVID-19. His treatment regimen included the use of convalescent plasma, oxygen therapy, steroids, high-dose antibiotics, broad-spectrum antiviral remdesivir, and anti–interleukin-6 monoclonal antibody (Tocilizumab) at various stages of the disease. Oxygen supplementation was required at the time of admission. The patient initially developed a cytokine release storm, and oxygen supplementation was initiated to manage his condition. Supportive care and multiple treatment regimens were used to successfully recover the patient’s health. With a rapid increase in number of confirmed cases worldwide, COVID-19 has become a major challenge to our health care system. With no available vaccines currently, the establishment of a combination of therapeutic drugs that effectively reduce disease progression is of utmost importance.     

Radiolabeling,quality control,and biological characterization of 177Lu‐labeled kanamycin

Kanamycin is an antibiotic, isolated from Streptomyces kanamyceticus, which is used to treat serious bacterial infections. The fact that the present radioligand ^99mTc‐kanamycin used for diagnosis is short‐lived, raised a need to label and study kanamycin with one of the most important beta (β) radiation emitting isotope ¹⁷⁷Lu. Labeling yield of ¹⁷⁷Lu‐kanamycin was confirmed by different chromatography techniques such as paper chromatography, TLC, HPLC. Several experiments were performed to optimize labeling with changing reaction conditions such as pH, temperature, amount of ligand, and reaction time. In vitro stability analysis was performed incubation with human serum. Electrophoresis analysis was also conducted to determine the charge on ¹⁷⁷Lu‐kanamycin. The biodistribution and scintigraphy were performed in normal mice and rabbit, respectively, at different time intervals of postinjection. ¹⁷⁷Lu‐kanamycin was prepared with very high yield (~100%), with excellent stability in vivo and in vitro (>99% 6 hr postprep.), at pH 7. Maximum labeling was achieved at less reaction time (15 min), with maximum conjugation of the ligand (12.5 mg) with ¹⁷⁷Lu. Electrophoresis analysis showed net neutral charge. The radioligand showed rapid clearance from body in biodistribution and scintigraphy studies. The preparation ¹⁷⁷Lu‐kanamycin could be used as a radio‐pharmaceutical for infection imaging purpose, especially when transporting the radioligand to long‐range distances.     

Anaesthesia for assisted conception: a survey of UK practice

A telephone survey was undertaken of all UK centres (total 70) licensed for performing in vitro fertilization (IVF) and gamete intra-fallopian transfer (GIFT) by the Human Fertilisation and Embryology Authority (HFEA). The survey was carried out during the months of November and December 1997. Thirty-seven (52.1%) centres were in the NHS sector and 33 (47.8%) in the private sector. A response was available from 60 (84%) centres. A standard questionnaire was used which requested information about the procedures carried out, anaesthetic technique and pharmacological agents used. Forty-seven centres carried out IVF, two centres GIFT and 11 centres both. Out of 58 centres carrying out IVF, sedation was used in 28, general anaesthesia in 17, sedation combined with regional anaesthesia in seven and regional anaesthesia in one. Five centres gave a choice. Out of 22 centres using general anaesthesia for IVF, 12 used inhalational agents (isoflurane eight, enflurane four, sevoflurane two), eight used total intravenous anaesthesia (TIVA) with propofol and two centres inhalational agents or TIVA. Propofol was the induction agent in all but two centres. For IVF under sedation, 18 centres used midazolam, five used diazepam, three used opioids, one used entonox and the remaining ones a combination. When sedation was combined with regional anaesthesia, four centres used midazolam, two used propofol, one used midazolam with propofol, one used opioids and one used entonox. The regional technique in the 11 centres was either paracervical block with lignocaine (eight) or subarachnoid block with bupivacaine (three). Systemic analgesia was secured with fentanyl (22), pethidine (16), alfentanil (15), diclofenac (14), piroxicam (two), ketorolac (one) and ibuprofen (one). Five centres did not use any opioids; 40 centres did not use any nonsteroidal agents (NSAIDs). Out of the 13 centres that carried out GIFT, 12 used general anaesthesia while the thirteenth gave the patient a choice between general or regional anaesthesia. 11 centres used inhalational agents (isoflurane nine, enflurane two) while two used TIVA with propofol; propofol was the induction agent used in six centres while thiopentone was used in five. The range of analgesics was wide--fentanyl in six centres, alfentanil in three, morphine in two, diclofenac in five and ketorolac in one. Two centres did not use any opioids and seven centres did not use an NSAID. The only agreement at present appears to be that halothane is an unwise choice for IVF. No other technique has yet been proven to be either advantageous or detrimental.     

Tongue reconstruction: recent advances

PURPOSE OF REVIEW: To examine the recent literature concerning advances in tongue reconstruction after tumor resection. RECENT FINDINGS: Reconstruction following resection of malignant tongue tumors remains one of the most difficult problems in head and neck oncology. Recent trends in tongue reconstruction have focused on optimizing speech and swallowing function and maximizing quality of life. In the recent literature, several new reconstructive strategies including omohyoid musculocutaneous and myofascial flaps overlayed with radial forearm free flaps have been described. In addition, several older reconstructive options, such as trapezius and pectoralis rotational flaps, have been revisited. There has also been a trend toward restoring innervation to these flaps rather than leaving them insensate. SUMMARY: Tongue cancer resection and subsequent reconstruction pose interesting challenges to the surgeon to maximize postoperative function and quality of life. Attention to the principles of tongue reconstruction and knowledge of the range of available reconstructive options can result in more favorable functional outcomes.     

Multiparametric analysis of preoperative lymphatic mapping with the use of combined deep plus superficial radiotracer injection technique in early breast cancer

OBJECTIVES: According to literature, combined tracer injection techniques seem to be the more powerful choice to eliminate technical and patient-related limitations. In this study, we analysed the quantitative performance parameters of combined deep plus superficial radiotracer injection and their correlation with a set of clinical, pathological and technical factors. METHODS: One hundred and sixteen women who underwent preoperative sentinel lymph node (SLN) mapping were studied prospectively. All patients received the simultaneous deep and superficial injection of 99mTc-nanocolloid. Mapping success rate, mean number of SLNs per patient and radiotracer uptake of SLNs were determined. The possible effects of age, tumour stage, laterality and location, type and time of previous biopsy, and SLN status on the quantitative parameters were analysed. RESULTS: Axillary SLNs were visualized in all cases. Mean number of axillary SLNs was 2.15 and advanced age (>50) significantly decreased the number of SLNs. Radiotracer uptake of SLNs was also significantly decreased by advanced age and a shorter time interval between biopsy and mapping (<10 days). Extra-axillary SLN visualization rates for medial, lateral and periareolar injection sites were 32%, 16% and 8%. Although SLN gamma probe counts were significantly higher in the single-day protocol, the 2-day protocol gave better contrast values which was also an important parameter in lesion detection. CONCLUSION: The combined radiotracer injection technique successfully demonstrated axillary and extra-axillary SLNs. Advanced age and previous biopsy time can lower the accuracy and reliability of SLN biopsy. Although periareolar injection gave the best results for the axilla, it was still insensitive for extra-axillary SLNs in spite of deep injection.