Assessment of RAdiopaque Patient IDentification Stickers (RAPIDS) for patient-scan correlation in a mass casualty incident.

PURPOSE: To qualitatively assess the legibility of radiopaque patient identification stickers and their effect on image quality. These stickers are intended for use as a part of a patient registration and identification pack utilized in a mass casualty incident (MCI), to prevent errors in correlating patients with their diagnostic imaging and reports. METHODS: Four different prototype designs of stickers with radiopaque identification numbers which are legible on radiographs and CT were created. These were affixed to head and thorax phantoms and scanned using standard imaging protocols. Images were reviewed qualitatively for legibility and the presence of image degradation due to the radiopaque sticker materials using Likert scales by four radiologists and four emergency physicians. RESULTS: All four prototypes were confidently legible on forehead, shoulder and sternum on CT on topogram and reconstructed images. Sticker positioning over the temple resulted in unreliable legibility on topogram. All prototypes were confidently legible on shoulder and sternum on CT and radiographs. Significant image degradation was reported on radiographs with sticker position over the sternum. The preferred anatomic position was the forehead. CONCLUSION: In a mass casualty incident, radiopaque patient identification stickers affixed to injured patients may help to ensure confidence in the correlation between patients and their imaging. Tested prototypes were found to be easily legible without substantial degradation of image quality. Preferred anatomical position and construction material was established. Consideration should be given to addition of such radiographic identity aides to MCI patient registration packs.

Change from transrectal to transperineal ultrasound-guided prostate biopsy under local anaesthetic eliminates sepsis as a complication.

Transrectal ultrasound-guided (TRUS) biopsy of the prostate is associated with increased risk of post-procedural sepsis with associated morbidity, mortality, re-admission to hospital, and increased healthcare costs. In the study institution, active surveillance of post-procedural infection complications is performed by clinical nurse specialists for prostate cancer under the guidance of the infection prevention and control team. To protect hospital services for acute medical admissions related to the coronavirus disease 2019 (COVID-19) pandemic, TRUS biopsy services were reduced nationally, with exceptions only for those patients at high risk of prostate cancer. In the study institution, this change prompted a complete move to transperineal (TP) prostate biopsy performed in outpatients under local anaesthetic. TP biopsies eliminated the risk of post-procedural sepsis and, consequently, sepsis-related admission while maintaining a service for prostate cancer diagnosis during the COVID-19 pandemic.

Freeze-etch studies of the plasma membrane of pulmonary endothelial cells.

Pulmonary endothelial cells are capable of metabolizing a variety of circulating hormonal substances. Indirect evidence indicates that some of the relevant enzymes are located on the plasma membrane. The associated caveolae are of special interest as globular subunits, possibly enzyme clusters, are evident in their membranes. In the present study, freeze-etch techniques were used to improve understanding of the fine structure of endothelial cells and to extend our investigations of possible sites of enzymes capable of metabolizing circulating vasoactive agents. As in other cells studied by freeze-etching, intramembranous particles are found on both inner aspects of the plasma membrane. In undifferentiated areas of plasma membrane, the particles appear to have a random distribution. These areas fracture such that approximately equal proportions of the particles adhere to the cytoplasmic aspect of the outer leaflet and the extracellular aspect of the inner leaflet. However, the particles organize into rosettes and plaques at the base of caveolae, and, after fracture, the rosettes and plaques adhere predominantly to the cytoplasmic aspect of the outer leaflet. The peculiar organization of particles in association with caveolae supports the concept that caveolae have a stomal skeletal structure and raises the possibility that the organization may be in some way related to pinocytosis.

Renin-like enzyme in the adrenal gland.

The rabbit adrenal gland contains an enzyme which reacts with renin substrate to form a vasopressor polypeptide, probably angiotensin I. In view of the strong effects of angiotensin on secretion of aldosterone and catecholamine, this finding suggests that there may be an intra-adrenal mechanism for the control of adrenal secretions.

Antibodies affecting metabolism of chicken erythrocytes: examination of schizophrenic and other subjects.

Human plasma contains an antibody which produces a complement-linked lysis of chicken erythrocytes and an associated marked stimulation of the cells' aerobic glycolysis. This appears to account for reported alteration in chicken erythrocyte metabolism produced by the plasmas of some schizophrenic patients.

Angiotensin I: metabolism by plasma membrane of lung.

(8-L-[(14)C] phenylalanine) angiotensin I is metabolized in one passage through blood-free lungs. Approximately 20 percent of the radioactivity emerges as angiotensin 11, the remainder as lower homologs. Radioactivity is not retained by the lungs but has the same volume of distribution and mean transit time as blue dextran, a compound unlikely to leave the intravascular space. Plasma membrane fractions of lung are capable of converting angiotensin I to angiotensin II. These data, taken together, indicate the circulating angiotensin I is metabolized by enzymes of the luminal surface of pulmonary endothelial cells.

Exocytosis in the adrenal medulla demonstrated by freeze-etching.

Replicas of fractured chromaffin cells are indicative of a range of activities thought to characterize exocytosis, including attachment of secretory vesicles to the plasma membrane, fusion, extrusion of contents, and membrane retrieval. Exocytosis sites are abundant on stimulated cells but are infrequent when calcium is omitted from the system.

Endothelial cells of bovine pulmonary artery lack receptors for C3b and for the Fc portion of immunoglobulin G.

Bovine pulmonary endothelial cells do not possess receptors for the 3b component of complement (C3b) or for the Fc portion of immunoglobulin G. The lack of these receptors may help explain the nonthrombogenic function of endothelial cells. Our findings rule out the possibility that endothelial cells participate in pulmonary immune complex disease through the binding of C3b or Fc fragments.

Endothelial projections as revealed by scanning electron microscopy.

Scanning electron micrographs of the endothelium of the pulmonary artery reveal that the entire surface is covered by a meshwork of irregular projections which vastly increase the surface area. The size and density of the projections suggest that they may function to direct an eddying flow of plasma along the endothelial surface.

Effects of aspirin and dipyridamole on the degradation of adenosine diphosphate by cultured cells derived from bovine pulmonary artery.

To improve understanding of the mechanisms by which ADP is degraded during passage through the pulmonary vascular bed, we examined cultured endothelial and smooth muscle cells of bovine pulmonmary artery for their abilities to metabolize [8-14C]ADP. ADP is rapidly converted to AMP and then to adenosine, hypoxanthine, and inosine. Inosine is the major metabolite produced by endothelial cells. Radioactivity (5-10%) is accumulated intracellularly primarily as ATP. Medium containing 50 micro M ADP incubated with endothelial cells rapidly loses its ability to aggregate platelets and becomes antiaggregatory under conditions in which prostacyclin is absent. The antiaggregatory activity is probably the result of accumulated adenosine. 10 micro M dipyridamole inhibits cellular uptake of radioactivity by greater than 90%, and inosine in the medium is largely replaced by adenosine. This is accompanied by increased anti-aggregatory activity of conditioned medium, which can be matched by authentic adenosine at the same concentration. 1 mM aspirin had no effect on the metabolism of ADP by endothelial cells. Our results suggest: (a) Metabolism of ADP during passage through the lung is mainly the result of endothelial ADPase. (b) ADP released from aggregating platelets can be converted to the antiaggregatory substance, adenosine. Dipyridamole may exert some of its antithrombotic actions by preventing the intracellular uptake of adenosine, thereby increasing its concentration near the site of thrombus formation. (c) The ability of the vessel wall to degrade ADP should not be compromised by the use of aspirin as an antithrombotic drug. (d) Endothelium may retain some of its antithrombogenicity when prostacyclin generation is impaired.

A radioassay for aminoacylproline hydrolase (aminopeptidase P) activity.

A radioassay was developed in which aminoacylproline hydrolase acts on Arg-Pro-Pro-[3H]benzylamide to yield arginine plus Pro-Pro-[3H]benzylamide. By stopping the reaction with base (0.1 M NaOH), the radioactive product is deprotonated to an organophilic form and is separable from the hydrophilic substrate by extraction of the alkaline aqueous solution with an organic solvent. When scintillants are included in the organic solvent, the enzyme:substrate reaction, extraction and quantification of Pro-Pro-[3H]benzylamide can all be conducted using a single liquid scintillation vial. Thus, aminoacylproline hydrolase activity is measured in terms of the rate of release of Pro-Pro-[3H]benzylamide. The substrate is obtainable at greater than 20 Ci/mmol, which enables its use under conditions of first-order enzyme kinetics. Conditions of near-zero order kinetics are readily attained by adding unlabeled substrate (Km 0.7 microM). The substrate is highly reactive (a 1:2000 dilution of guinea pig plasma hydrolyzed greater than 10% of the substrate during a 10 min incubation at 37 degrees C) and specific in that it is not degraded by leucine aminopeptidase, aminopeptidase A or N, dipeptidyl peptidase IV nor prolyl endopeptidase. The assay was used to measure aminoacylproline hydrolase specific activities in tissues of rat and guinea pig. Activity was found in virtually all major tissues of both species, and some guinea pig tissues (e.g. kidney and plasma) were found to be notably rich sources of the enzyme.

Bradykinin-induced release of prostacyclin and thromboxanes from bovine pulmonary artery endothelial cells. Studies with lower homologs and calcium antagonists.

Bovine pulmonary artery endothelial cells, in serum-free culture medium, release small quantities of prostacyclin and thromboxane A2 (3-10 and 0.1-0.3 ng/ml; measured as immunoreactive 6-ketoprostaglandin F1 alpha and thromboxane B2, respectively). The release of these substances is stimulated by up to 20-fold during a 3 min incubation with the vasodilator, bradykinin (Arg1-Pro2-Pro3-Gly4-Phe5-Ser6-Pro7-Phe8-Arg9). Endothelial cells incubated with [3H]arachidonic acid for 24 h and then exposed to bradykinin for 3 min release 3H into the medium, approximately 65% of which co-chromatographs with 6-ketoprostaglandin F1 alpha and 3% with thromboxane B2. The effects of bradykinin are dose-related and are often discernible when the hormone is used at concentrations believed to occur physiologically (10 pg/ml; approximately 10 pM). Furthermore, the bradykinin molecule must be intact: none of its lower homologs affects the release of prostacyclin, thromboxane A2, or 3H unless used at concentrations (1 microM or higher) unlikely to be achieved in vivo. The release appears to involve calcium uptake and calmodulin: it is abolished by EGTA (5 mM) and inhibited by the 'slow channel' calcium antagonists, verapamil and nifedipine (10-100 microM), and by the calmodulin inhibitor, trifluoperazine (3-30 microM). Our findings suggest that bradykinin exerts some of its hormonal effects by acting on specific receptors possessed by vascular endothelial cells; receptor activation is associated with calcium transport, arachidonate mobilization, and a selective synthesis of prostacyclin, a vasodilator in its own right.

Purification and characterization of guinea pig serum aminoacylproline hydrolase (aminopeptidase P).

Aminoacylproline hydrolase (EC 3.4.11.9) of guinea pig serum has been obtained as two apparently homogeneous isoforms. Dialyzed serum was chromatographed successively on Affi-gel blue, hydroxyapatite, DE-cellulose, phenyl-Sepharose, an affinity matrix for angiotensin converting enzyme and concanavalin-Sepharose. On the latter matrix, 68% of the enzyme activity was eluted with alpha-methyl mannoside at 10 and 100 mM, and 29% was eluted with alpha-methyl glucoside, 500 mM, at 56 degrees C. The two fractions ('biantennary' and 'high mannose' fractions, respectively) were concentrated and then chromatographed separately on Sephacryl S-200HR. Both fractions were eluted as expected for a globular protein of Mr 217,000. On SDS-PAGE, under reducing and non-reducing conditions, each of the concanavalin-Sepharose fractions was separated into two protein bands, Mr 89,000 and Mr 81,500. Each of the bands was found to be N-blocked when N-terminal amino acid sequencing was attempted. The reaction of the 'biantennary' fraction with the synthetic substrate Arg-Pro-Pro-[3H]benzylamide was characterized in part: Km 0.7 microM, kcat 124.6 min-1, kcat/Km 1.78.10(8) M-1 min-1. Hydrolysis of the substrate was strongly inhibited by bradykinin and those of its lower homologs that contain two adjacent proline residues. Cu2+ was strongly inhibitory. Co2+ at 30 microM activated the enzyme, as did Mn2+, Mg2+ and Ca2+ at higher concentrations. Sulfhydryl compounds, including captopril, inhibited the enzyme as did 1,10-phenanthroline. Iodoacetamide and N-ethylmaleimide had no effects, but 4-hydroxymercuribenzoate conferred a partial inhibition over a remarkably wide concentration range: 0.34-1400 microM. Amastatin and bestatin did not inhibit the enzyme. Aminoacylproline hydrolase of guinea pig serum appears to be a heterogeneous, glycosylated metallo-enzyme with a high affinity for bradykinin and related peptides in which the sequence Pro-Pro, Xaa-Pro-Pro or Xaa-Pro-Hyp is N-terminal.

Cloning and tissue distribution of human membrane-bound aminopeptidase P.

Complementary DNA clones encoding human membrane-bound aminopeptidase P (AmP) were isolated by reverse transcription-polymerase chain reaction (RT-PCR) of human kidney and lung poly (A)+ RNA. Comparison of the human AmP sequence to that of the pig shows significant evolutionary divergence with only 83% amino acid sequence identity between the two species. Northern hybridization analysis and RT-PCR suggests that the soluble and membrane-bound forms of human AmP are products of two distinct genes or, through alternative splicing, have different C-terminal sequences.

Value of serial measurement of serum angiotensin converting enzyme in the management of sarcoidosis.

Serial serum samples from 35 patients with histologically proved sarcoidosis were measured for angiotensin converting enzyme activity. The serum angiotensin converting enzyme (SACE) activity was compared with the clinical activity of sarcoidosis. In both the treated and untreated group, the SACE activity closely paralleled the clinical status. There was agreement between SACE index and clinical index in 81 of 101 paired observations. It appears that SACE activity is a good reflection of granulomatous activity in sarcoidosis. Once the decision has been made to treat sarcoidosis, serial SACE determinations are helpful in monitoring the dose and duration of therapy with corticosteroids.

The effect of previous thoracic surgery on gallium uptake in the chest.

To determine the frequency, average duration, and characteristic patterns of persistent gallium uptake caused by thoracotomy, serial postsurgical scans of 51 patients were reviewed. In each of these cases a thoracotomy had been performed for resection of lung cancer, and there had been no evidence of recurrent tumor for at least 2 yr following surgery. Postoperative gallium activity due to non-neoplastic postoperative changes occurred in 15 patients. Five of six patients scanned within 3 mo of surgery and six of 21 scanned 3 to 6 mo following surgery showed persistent uptake at the operative site. All 13 patients who had subsequent scans demonstrated eventual clearing. Activity persisted more than 18 mo postoperatively in only one patient. Patterns of gallium accumulation included both focal chest wall uptake at the incision site and diffuse pleural activity.

Nuclear imaging analysis of human low-density lipoprotein biodistribution in rabbits and monkeys.

We have evaluated the biodistribution of human low-density lipoprotein (LDL) radiolabeled with 99mTc or with 123I-tyramine cellobiose in rabbits and in rhesus monkeys. Biodistribution was assessed after intravenous injection of radiolabeled LDL by quantitative analysis of scintigrams, counting of excreta, and counting of tissues at necropsy. Both rabbits and monkeys showed lower renal uptake (123I:99mTc approximately 1:3, as regional percent injected activity corrected for physical decay) and excretion (1:2 to 1:4), but higher hepatic (1.5:1 to 2:1) and cardiac (1.7:1 to 4:1) uptake of 123I than of 99mTc. Adrenals were visualized in normolipemic animals with 123I-tyramine cellobiose-LDL but not with 99mTc-LDL. Hyperlipemic animals showed increased cardiac (up to six-fold) and decreased hepatic activity (by 50%-60%) of both radionuclides. We conclude that 123I-tyramine cellobiose-LDL is better suited than 99mTc-LDL for dynamic studies of LDL metabolism in vivo.

Angiotensin-converting enzyme in bovine, feline, and human ocular tissues.

Angiotensin-converting enzyme was shown to be present in retinal vessels and neural retina of feline, bovine, and human eyes. It was also demonstrated in the other ocular tissues of feline eyes, in especially high concentration in the highly vascular uveal layer. Its role in the physiology of ocular blood flow and neurophysiology is uncertain, especially in the retina where circulating angiotensin and bradykinin are confined to the intravascular space by the blood-retina barrier, and sufficient data are not available to describe these peptides as transmitters or modulator molecules in the retina.

Detection and assessment of severity of tricuspid regurgitation using first-pass radionuclide angiography and comparison with pulsed Doppler echocardiography.

Noninvasive detection and semiquantitative assessment of tricuspid regurgitation (TR) were performed using first-pass radionuclide angiography (RNA), by sampling a region of interest over the right atrium for any tracer entering the right atrium during right ventricular systole. The relative amount of tracer entering the right atrium was quantitated and the results were compared with semiquantitative Doppler echocardiographic grading of TR severity. Using the right ventricular time-activity curve to define end-diastolic and end-systolic frames, the right atrial counts for the 2 or 3 cardiac cycles after the peak right ventricular counts were summed. The right atrial "injection fraction" was calculated using the following formula: [(end-systolic counts - end-diastolic counts)/(end-diastolic counts)] X 100%. The right atrial injection fraction was examined in 51 patients who had good quality RNA and Doppler studies. Of 27 patients with no evidence of TR by Doppler, 26 had a negative right atrial injection fraction. All 24 patients with a positive Doppler for TR had a positive right atrial injection fraction. Comparison of right atrial injection fraction grade ranges with semiquantitative grades of TR severity on Doppler revealed identical grades in 21 of the 24, with a single grade difference in the remaining 3 patients. Thus, right atrial time-activity curve quantitation during routine first-pass RNA allows detection and grading of the severity of TR, with results very similar to pulsed Doppler echocardiography. This simple procedure is easily appended to the evaluation of ventricular performance with first-pass RNA.

Inhibition of endothelial-bound angiotensin converting enzyme, in vivo.

1. We determined apparent Ki constants of two inhibitors, captopril and CL242,817, for pulmonary endothelial-bound angiotensin converting enzyme (ACE) in anaesthetized rabbits. [3H]-benzoyl-Phe-Ala-Pro was used as the substrate. The apparent kinetic parameters Km and Amax (product of Vmax and microvascular plasma volume) were measured, as was the ratio (Amax/Km) (measured under first order reaction conditions) before and 30s after the i.v. administration of captopril 10 nmol kg-1 or CL242,817, 35 nmol kg-1. 2. Under mixed order reaction conditions, ([S] greater than or equal to Km), apparent Km values increased from 12.2 +/- 1.9 microM to 32.9 +/- 3.3 microM (P less than 0.05) in the captopril-treated rabbits and from 9.3 +/- 2.3 microM to 45.8 +/- 9.8 microM (P less than 0.05) in the CL242,817-treated rabbits, indicative of competitive inhibition. However, apparent Amax values decreased from 10.3 +/- 2.1 to 4.5 +/- 0.8 mumol min-1 (P less than 0.05) and 8.9 +/- 1.7 to 4.8 +/- 0.5 mumol min-1 (P less than 0.05), respectively. 3. Under first order reaction conditions ([S] much less than Km), the Amax/Km ratio decreased from 763 +/- 100 to 125 +/- 38 ml min-1 (P less than 0.05) and 1009 +/- 149 to 126 +/- 44 ml min-1 (P less than 0.05) in the captopril- and CL242,817-treated groups respectively. 4. When the single pass transpulmonary binding of 80pmol [3H]-RAC-X-65 (an ACE inhibitor) was measured in additional rabbits, a significant (P < 0.05) decrease in RAC-X-65 binding was observed 30s after captopril (80% decrease) or CL242,817 (85% decrease), a result expected for a loss of catalytically active enzyme mass due to tightly bound captopril or CL242,817. 5. These results indicate that, in vivo, both captopril and CL242,817 are competitive, tight binding inhibitors of lung ACE. Furthermore, they suggest means for evaluating the interaction of other potential ACE inhibitors with the pulmonary endothelial membrane-bound enzyme, in vivo, possibly in phase I clinical trials.