Factors associated with perceived Anaplasma marginale infection and clinical anaplasmosis cases on beef operations in California.

Bovine anaplasmosis is a tick-borne disease caused by Anaplasma marginale in the United States. The objective of this study was to use a survey tool to generate information for beef operations in California on anaplasmosis prevention and control management, including to what extent management activities were informed by perceived herd-level exposure to A. marginale infection or occurrence of clinical anaplasmosis cases. We mailed 2,621 questionnaires with questions on Anaplasma status, herd demographics, anaplasmosis control and prevention measures, and environmental factors to beef ranchers in California in October 2020. Survey-weighted chi-square tests were used to compare management differences according to perceived Anaplasma infection status. Generalized estimating equations (GEEs) were used to analyze whether region of California, management practices, or environmental factors were associated with reported clinical cases of anaplasmosis in the previous five years. A total of 466 questionnaires describing 749 herds were obtained and used in this study. Use of management measures, including deliberate exposure of calves to ticks, vaccination for Anaplasma, infection control through antibiotics in feed, maintaining a completely closed herd, blood testing for Anaplasma on all herd additions, and taking no anaplasmosis control and prevention measures, were significantly different between herds with or without perceived A. marginale infection based on producers' self-declared status. The overall perceived prevalence for Anaplasma infection and reported clinical cases of anaplasmosis at the herd level was 26.0 % (95 % CI: 24.3-27.7 %) and 17.1 % (95 % CI: 15.6-18.6 %) respectively, with the highest perceived infection and case numbers reported in the Central Coast region. In the GEE model, higher odds of reporting clinical cases of anaplasmosis in the previous five years were observed in cattle located in the Central Coast region, cattle within a large herd, cattle that are treated with tick/fly control, cattle in a completely closed herd, and cattle receiving Anaplasma vaccine. Anaplasma infection and bovine anaplasmosis status may be underestimated in beef herds in California based on previous study results. Changing needles between cattle after injections and conducting blood testing for Anaplasma on herd additions are important Anaplasma management measures that are infrequently implemented in beef herds in California. The results show a need for producer education to improve producers' awareness of bovine anaplasmosis and implement proper measures for disease control and prevention.

The impact of sleep, physical activity and sedentary behaviour on symptoms of depression and anxiety before and during the COVID-19 pandemic in a sample of South African participants.

During lockdowns associated with the COVID-19 pandemic, individuals have experienced poor sleep quality and sleep regularity, changes in lifestyle behaviours, and heightened depression and anxiety. However, the inter-relationship and relative strength of those behaviours on mental health outcomes is still unknown. We collected data between 12 May and 15 June 2020 from 1048 South African adults (age: 32.76 ± 14.43 years; n = 767 female; n = 473 students) using an online questionnaire. Using structural equation modelling, we investigated how insomnia symptoms, sleep regularity, exercise intensity/frequency and sitting/screen-use (sedentary screen-use) interacted to predict depressive and anxiety-related symptoms before and during lockdown. We also controlled for the effects of sex and student status. Irrespective of lockdown, (a) more severe symptoms of insomnia and greater sedentary screen-use predicted greater symptoms of depression and anxiety and (b) the effects of sedentary screen-use on mental health outcomes were mediated by insomnia. The effects of physical activity on mental health outcomes, however, were only significant during lockdown. Low physical activity predicted greater insomnia symptom severity, which in turn predicted increased depressive and anxiety-related symptoms. Overall, relationships between the study variables and mental health outcomes were amplified during lockdown. The findings highlight the importance of maintaining physical activity and reducing sedentary screen-use to promote better sleep and mental health.

Subliming ice surfaces: freeze-etch electron microscopy.

Vacuum sublimation of oriented single crystals of ice at temperatures from -110 to -60 degrees Celsius was studied by electron microscopy with the freeze-etch technique. Sublimation etches the ice surface to produce pits and asperities and above -85 degrees Celsius causes extreme surface roughening. The etch pits are ascribed to surface dislocations, and the extreme roughening is ascribed to the departure from unity of the vaporization coefficient. The asperities could not be attributed to impurities; they may be related to the whiskers that others have observed at higher temperatures.

The impact of a fast bowling spell on physiological, perceptual and performance responses in non-elite cricketers.

Background: The demands placed on fast bowlers may elicit unique responses that contribute towards increased injury risk and comprised performance capabilities. Despite this, very few investigations have attempted to quantify these demands and their impact on performance in cricketers. Objective: This investigation attempted to quantify the effects of a fast bowling protocol on the musculoskeletal, physiological and perceptual responses of fast bowlers; as well as ball speed and accuracy. Methods: Eight young adult bowlers (20 ± 2 years) participated in a 10-over bowling protocol that had been separated by intermittent fielding drills into three bowling spells respectively (4-, 3- and 3- overs). Selected responses were collected throughout the protocol. Results: Functional strength was measured and showed no change. Heart rate responses increased significantly (p<0.05) at the start of the bowling protocol. Local ratings of perceived exertion increased significantly (p<0.05) as a function of exercise duration, while low to moderate intensities of perceived discomfort were noted in the anterior and posterior shoulder areas, upper portion of the lower limb musculature, as well as in the middle and lower back regions. Performance responses experienced no significant change. Conclusion: There was no significant change in ball release speed and accuracy across the bowling protocol. Lower limb muscle power remained consistent and heart rates reached a steady state after the first over. In comparison, local ratings of perceived effort and body discomfort increased over time, which could mean that those unchanged measures do not accurately reflect fatigue or that perceptions are a more effective indicator of impending fatigue.

[Daily management of acute pericarditis: clinical and paraclinical outcomes, etiological diagnosis]. / Prise en charge au quotidien des péricardites aiguës: présentation clinique, paraclinique, diagnostic étiologique.

INTRODUCTION: Acute pericarditis is a frequent hospitalization cause. A prospective, bicentric study aimed at different goals: population description, aetiologies screening, and evaluation of the interest of a coordinated and combined management between cardiologists and internists. PATIENTS AND METHODS: Between May 2005 and September 2007, all patients admitted for acute pericarditis were prospectively enrolled. Physical examination, ECG, echocardiography, biological screening were performed. Patients were asked to consult both cardiologist and internist, one month later. RESULTS: Hundred and three patients were enrolled (mean age 43 years). Clinical outcome was classical in 60% of cases. ECG was typical in 59%. Troponin elevation was noted in 30% of patients. CRP was normal at diagnosis in 27% of patients, and increased significantly at first day (P=0.002). Possible cause was identified in 44 patients. In 26 patients (24.3%), precise diagnosis was performed: six cancers, one hemopathy, three connectivities, one EBV and one parvovirus B19 seroconversions, two untreated HIV patients, four inflammatory diseases, three endocrinology troubles, one oesophagitis, one dental sepsis, one amyloidosis, one acute pancreatitis, one declined dialysis indication. Eighteen de novo diagnoses (16.5%) were performed, out of them at least 12 benefited from specific management. CONCLUSION: Population of patients admitted for acute pericarditis are very heterogeneous. Our co-management between internists and cardiologists aims to diagnose earlier and easier curable diseases. Long-term follow-up remains of great interest, in order to diagnose later other disorders, which remained hidden, and to follow evolution of the population.

Prevalence of obstructive sleep apnoea in acute coronary syndrome: Routine screening in intensive coronary care units.

INTRODUCTION: Increased evidence has shown that, despite the maximum care afforded to patients admitted with acute coronary syndromes (ACS), a residual risk of mortality remains, in which obstructive sleep apnoea (OSA) appears to be a largely undiagnosed factor, particularly in the intensive cardiac care unit (ICCU). The purpose of this study is to determine whether the systematic screening for sleep-disordered breathing (SDB) is feasible and may be recommended. The aims of our study are to determine: (1) The estimated prevalence of OSA in patients admitted to the ICCU for ACS determined by a validated, user-friendly portable screening device; (2) The feasibility of the screening in this context; (3) To assess any negative impact of OSA on the severity of ACS. PATIENTS AND METHODS: This is an observational study of 101 patients admitted to the ICCU for ACS showing no clinical evidence of heart failure (HF). In the 24-72hours following admission, they underwent an overnight sleep study using a 3-channel portable screening device with automatic analysis. RESULTS: Sixty-two out of the 101 patients proved positive to the screening test, and its feasibility was acceptable. OSA patients tended to have greater peak levels of hs-cTnT (3685±3576ng/L versus 2830±3333ng/L, P=0.08) than the non-OSA group. Compared with the non-OSA group, OSA patients presented more severe ACS, with a greater average GRACE score at admission of 112.2±26.3 (versus 98.4±19.2, P<0.001). In the OSA group, we found a statistically significant inverse correlation between the apnoea-hypopnea index (AHI) and the left ventricular ejection fraction (LVEF) in the linear regression analysis (r=-0.26; P=0.037). CONCLUSIONS: A systematic screening of patients in the ICCU is acceptable. OSA is frequently found in the acute phase of ischaemic heart disease and its presence is associated with more severe ACS and a poorer left ventricle systolic function.

Viruses: agents of coral disease?

The potential role of viruses in coral disease has only recently begun to receive attention. Here we describe our attempts to determine whether viruses are present in thermally stressed corals Pavona danai, Acropora formosa and Stylophora pistillata and zoanthids Zoanthus sp., and their zooxanthellae. Heat-shocked P. danai, A. formosa and Zoanthus sp. all produced numerous virus-like particles (VLPs) that were evident in the animal tissue, zooxanthellae and the surrounding seawater; VLPs were also seen around heat-shocked freshly isolated zooxanthellae (FIZ) from P. danai and S. pistillata. The most commonly seen VLPs were tail-less, hexagonal and about 40 to 50 nm in diameter, though a diverse range of other VLP morphotypes (e.g. rounded, rod-shaped, droplet-shaped, filamentous) were also present around corals. When VLPs around heat-shocked FIZ from S. pistillata were added to non-stressed FIZ from this coral, they resulted in cell lysis, suggesting that an infectious agent was present; however, analysis with transmission electron microscopy provided no clear evidence of viral infection. The release of diverse VLPs was again apparent when flow cytometry was used to enumerate release by heat-stressed A. formosa nubbins. Our data support the infection of reef corals by viruses, though we cannot yet determine the precise origin (i.e. coral, zooxanthellae and/or surface microbes) of the VLPs seen. Furthermore, genome sequence data are required to establish the presence of viruses unequivocally.

Five isoenzymes of protein kinase C are expressed in normal and STZ-diabetic rat hepatocytes: effect of phorbol 12-myristate 13-acetate.

Using isoenzyme-specific antisera, five Protein Kinase Cs (PKCs) were detected in cytosol and membrane hepatocytes from normal rats: PKC alpha (80 kDa), PKC beta II (40, 50, 55, 85 kDa), PKC delta (74, 76 kDa), PKC epsilon (95 kDa), PKC zeta (65, 70 kDa). STZ-diabetes induced a lower expression of the five PKCs, a higher localization in the cytosol, a preferential expression of PKC delta as the 76 kDa phosphorylated species and a decreased kinase activity towards Histone III-S. A 1 microM phorbol 12-myristate 13-acetate (PMA) incubation induced similar translocation to the membrane of PKCs alpha, native 85 kDa beta II and epsilon. The 74 kDa PKC delta was switched to the 76 kDa species, the normal form in STZ-diabetic cells. The truncated PKC beta II and PKC epsilon were unchanged.

Lidocaine causes a reversible, concentration-dependent increase in defibrillation energy requirements.

To investigate the influence of lidocaine on the energy requirements for internal defibrillation, lidocaine (n = 8) or saline solution (n = 12) was administered by intravenous infusion to 20 pentobarbital-anesthetized dogs, and the likelihood of successful defibrillation was examined at various shock energy levels before and after treatment. After lidocaine administration to a mean steady state concentration of 5.6 +/- 2.7 micrograms/ml, the mean energy required to achieve 50 and 90% success in defibrillation (E50 and E90) increased by 61.1 +/- 34.1% (mean +/- SD, p less than 0.005) and 47.1 +/- 28.6% (p less than 0.005), respectively. The steady state log lidocaine concentration correlated positively with the observed increase in E50 (r = 0.887, p less than 0.01) over a concentration range from 1.95 to 9.8 micrograms/ml. In a related experiment, lidocaine infusion was administered to five dogs and then abruptly discontinued. At energy levels achieving a mean 90.0 +/- 10.0% success in defibrillation before treatment, only 43.3 +/- 23.4% success was achieved after 60 minutes of the lidocaine infusion (p less than 0.01) at a mean plasma concentration of 8.4 +/- 2.1 micrograms/ml. The percent of successful defibrillations returned to baseline value (92.0 +/- 18.0%, p less than 0.01) after drug washout at a time when mean lidocaine concentration had declined to 1.8 +/- 0.5 microgram/ml. Lidocaine causes a reversible, concentration-dependent increase in the energy requirements for successful defibrillation; recommendations to administer lidocaine to patients with ventricular fibrillation resistant to defibrillation may need to be reviewed.

Mexiletine antagonizes effects of sotalol on QT interval duration and its proarrhythmic effects in a canine model of torsade de pointes.

OBJECTIVES: The arrhythmogenic and electrophysiologic properties of sotalol, a class III antiarrhythmic drug, administered alone and in combination with mexiletine, a class I antiarrhythmic drug, were compared in conscious dogs predisposed to torsade de pointes arrhythmias. BACKGROUND: The utility of sotalol is limited by proarrhythmia related to excessive delays in repolarization. The addition of mexiletine may limit the risk of torsade de pointes because it reduced in vitro the sotalol-induced increase in action potential duration. METHODS: Two studies were performed in eight hypokalemic dogs (plasma potassium level < or = 3.2 mmol/liter) with chronic atrioventricular block (mean ventricular cycle length, RR 1,100 ms) at 3-day intervals using a crossover protocol. Intravenous sotalol (4.5 + 1.5 mg/kg body weight per h) alone was given for 2 h, or, on another day, an intravenous mexiletine infusion (4.5 + 1.5 mg/kg per h) was begun 30 min before sotalol infusion. Spontaneous ventricular cycle length and QT interval and ventricular effective refractory period at the 1,000-ms pacing cycle length were measured at baseline and 30 min after the onset of each drug infusion. The electrocardiogram (ECG) was continuously monitored for torsade de pointes. RESULTS: Sotalol plus mexiletine and sotalol alone had a significant (p < or = 0.05) and similar effect on ventricular cycle length (+ 800 +/- 93 vs. + 690 +/- 104 ms [mean +/- SEM]) and ventricular effective refractory period (+ 20 +/- 4 vs. + 25 +/- 4 ms), but sotalol plus mexiletine had a lesser effect on QT interval (+ 20 +/- 6 vs. + 50 +/- 8 ms, p < or = 0.05). Torsade de pointes is less frequent (one of eight dogs vs. six of eight dogs, p = 0.02) with sotalol plus mexiletine than with sotalol alone. CONCLUSIONS: The coadministration of a class Ib agent can reduce the proarrhythmic potential of a class III drug in experimental animals predisposed to torsade de pointes arrhythmias and further suggests the clinical utility of such a strategy.

Postoperative exercise tolerance after aortic valve replacement by small-size prosthesis: functional consequence of small-size aortic prosthesis.

OBJECTIVES: The objective of this study was to determine whether a small-size valve prosthesis contributes to exercise intolerance, as assessed by VO2 measurement during an exhaustive cycle ergometer exercise. BACKGROUND: The determinants of exercise capacity after mechanical aortic replacement are not well known. The selection of small valve sizes has, however, been described as an independent predictor of exercise intolerance as assessed by exercise duration. Maximal oxygen uptake (VO2max) is a good index of exercise tolerance. METHODS: Fourteen patients were eligible, with a mean age of 62 +/- 6 years. Before surgery, the mean left ventricular ejection fraction (LVEF) was 73 +/- 8%. Two valve types with small diameter (19 to 21 mm) were used: Medtronic Hall and St Jude Medical. A healthy sedentary control group (n = 14) paired for age, weight and size was constituted. After one year of follow-up, cardiorespiratory tests were performed. In addition, the gradients through the prostheses were determined by continuous pulse Doppler at rest and immediately after the cardiorespiratory test. RESULTS The exercise tolerance was not significantly different between the control group and patient group: VO2 peak (21.7 vs. 20.4 ml/kg/min; p = 0.42), workloads (115 vs. 93 W; p = 0.13) and ventilatory parameters were similar. The mean and peak gradients at rest and during exercise were not correlated with VO2max. CONCLUSIONS: Valve replacement by small aortic prosthesis does not seem to be a factor of exercise intolerance as assessed by VO2max in patients without LVEF dysfunction before surgery.

[Rhythm disorders and cardiac crypto-malformations]. / Troubles du rythme et crypto-malformations cardiaques.

Faced with a cardiac arrhythmia occuring in an apparently healthy heart, it is necessary to perform an anatomical investigation to detect any unsuspected anomalies. Congenital cardiopathy must certainly be excluded, as this is often responsible for rhythm disorders and/or cardiac conduction defects. Similarly, any acquired conditions, cardiomyopathy, or cardiac tumour must be sought. However, the possibility should always be considered of a minimal congenital malformation, which could be repsonsible for: any type of cardiac arrhythmia: rhythm disorder or conduction defect at the atrial, junctional or ventricular level, with a benign or serious prognosis. Unexpected therapeutic difficulties during radiofrequency ablation procedures or at implantation of pacemakers or defibrillators. Together with rhythm studies, the investigation of choice is high quality imaging, either the classic left or right angiography or the more modern cardiac CT or intracardiac mapping.

Troponin elevation after black widow spider envenomation.

Black widow spider envenomation generally results in self-limiting pain that can be treated in the emergency department (ED) with analgesics and benzodiazepines, usually with no further intervention. Occasionally, a patient has to be admitted or treated with antivenom for refractory pain or a venom-induced complication. We present the case of an 84-year-old man who presented to our ED with chest pain and dyspnea after being bitten on the foot by a western black widow spider (Lactrodectus hesperus). His initial cardiac troponin I (cTnI) was elevated at 0.07 ng/ml and continued to rise to a peak of 0.17 ng/ml. He also had rhabdomyolysis, another uncommon complication of black widow envenomation. An elevated cTnI generally signifies myocardial injury and is rarely seen after black widow envenomation. We discuss the possible etiologies for an elevated cardiac biomarker, in this context, and review potentially serious complications of widow spider envenomation presenting with chest symptoms and an elevated cardiac biomarker.

Microfluidics assisted generation of innovative polysaccharide hydrogel microparticles.

Capillary flow-based approach such as microfluidic devices offer a number of advantages over conventional flow control technology because they ensure highly versatile geometry and can be used to produce monodisperse spherical and non-spherical polymeric microparticles. Based on the principle of a flow-focusing device to emulsify the coflow of aqueous solutions in an organic phase, we were able to produce the following innovative polysaccharide hydrogel microparticles: - Janus hydrogel microparticles made of pectin­pectin (homo Janus) and pectin­alginate (hetero Janus) were produced. The efficiency of separation of the two hemispheres was investigated by confocal scanning laser microscopy (CSLM) of previously labelled biopolymers. The Janus structure was confirmed by subjecting each microparticle hemisphere to specific enzymatic degradation. As a proof of concept, free BSA or BSA grafted with dextran, were encapsulated in each hemisphere of the hetero Janus hydrogel microparticles. While BSA, free or grafted with dextran, was always confined in the alginate hemisphere, a fraction of BSA diffused from the pectin to the alginate hemisphere. Methoxy groups along the pectin chain will be responsible of the decrease of the number of attractive electrostatic interactions occurring between amino groups of BSA and carboxylic groups of pectin. - Pectin hydrogel microparticles of complex shapes were successfully produced by combining on-chip the phenomenon of gelation and water diffusion induced self-assembly, using dimethyl carbonate as continuous phase, or by deformation of the pre-gelled droplets off-chip at a fluid­fluid interface. Sphere, oblate ellipsoid, torus or mushroom-type morphologies were thus obtained. Moreover, it was established that after crossing the interface during their collect, mushroom-type microparticles did not migrate in the calcium or DMC phase but stayed at the liquid­liquid interface. These new and original hydrogel microparticles will open up opportunities for studying relationships between combined enzymatic hydrolysis and active release for Janus particles and relationships between shape and swelling behaviour for anisotropic pectin microparticles.

Microfluidics-assisted generation of stimuli-responsive hydrogels based on alginates incorporated with thermo-responsive and amphiphilic polymers as novel biomaterials.

We used a droplet-based microfluidics technique to produce monodisperse responsive alginate-block-polyetheramine copolymer microgels. The polyetheramine group (PEA), corresponding to a propylene oxide /ethylene oxide ratio (PO/EO) of 29/6 (Jeffamine(®) M2005), was condensed, via the amine link, to alginates with various mannuronic/guluronic acids ratios and using two alginate:jeffamine mass ratios. The size of the grafted-alginate microgels varied from 60 to 80 µm depending on the type of alginate used and the degree of substitution. The droplet-based microfluidics technique offered exquisite control of both the dimension and physical chemical properties of the grafted-alginate microgels. These microgels were therefore comparable to isolated grafted-alginate chains in retaining both their amphiphilic and thermo-sensitive properties. Amphiphilicity was demonstrated at the oil-water interface where grafted-alginate microgels were found to decrease interfacial tension by ∼ 50%. The thermo-sensitivity of microgels was clearly demonstrated and a 10 to 20% reduction in size between was evidenced on increasing the temperature above the lower critical solution temperature (TLCST) of Jeffamine. In addition, the reversibility of thermo-sensitivity was demonstrated by studying the oil-water affinity of microgels with temperature after Congo red labeling. Finally, droplet-based microfluidics was found to be a good and promising tool for generating responsive biobased hydrogels for drug delivery applications and potential new colloidal stabilizers for dispersed systems such as Pickering emulsions.

Adaptive servo-ventilation: How does it fit into the treatment of central sleep apnoea syndrome? Expert opinions.

The preliminary results of the SERVE-HF study have led to the release of safety information with subsequent contraindication to the use of adaptive servo-ventilation (ASV) for the treatment of central sleep apnoeas in patients with chronic symptomatic systolic heart failure with left ventricular ejection fraction (LVEF) ≤ 45%. The aim of this article is to review these results, and to provide more detailed arguments based on data from the literature advocating the continued use of ASV in different indications, including heart failure with preserved LVEF, complex sleep apnoea syndrome, opioid-induced central sleep apnea syndrome, idiopathic central SAS, and central SAS due to a stroke. Based on these findings, we propose to set up registers dedicated to patients in whom ASV has been stopped and in the context of the next setting up of ASV in these specific indications to ensure patient safety and allow reasoned decisions on the use of ASV.

[Appropriate medication prescribing in older people]. / Bon usage des médicaments chez le sujet âgé.

Drug-induced adverse effects are one of the main avoidable causes of hospitalization in older people. Numerous lists of potentially inappropriate medications for older people have been published, as national and international guidelines for appropriate prescribing in numerous diseases and for different age categories. The present review describes the general rules for an appropriate prescribing in older people and summarizes, for the main conditions encountered in older people, medications that are too often under-prescribed, the precautions of use of the main drugs that induce adverse effects, and drugs for which the benefit to risk ratio is unfavourable in older people. All these data are assembled in educational tables designed to be printed in a practical pocket format and used in daily practice by prescribers, whether physicians, surgeons or pharmacists.

Kinetic analysis of epidermal growth factor endocytosis in rat hepatocytes. Effects of diabetes.

In the present study we followed the different steps of epidermal growth factor receptor (EGF-R) endocytosis in freshly isolated rat hepatocytes. Hepatocytes exhibit two classes of surface EGF receptors consisting of approximately 5,000 high-affinity sites (Kd = 15 pM) and 166,000 low-affinity sites (Kd = 670 pM). Binding of labeled EGF to hepatocytes permeabilized by digitonin shows that 75% of the total EGF-R are localized at the cell surface. At 37 degrees C, hepatocytes continuously internalized and degraded EGF in spite of a down-regulation of cell surface receptors. The internalization rate constants measured as a function of a range 125I-EGF concentrations (0.01 - 5 nM) involving various degrees of EGF-R occupancy show superimposable curves. This indicates that the specific internalization rate of EGF-R complex is independent of receptor occupancy. Streptozotocin-induced diabetes reduces the number of low-affinity EGF-R to 50,000 and produces a complete loss of high-affinity sites. The dynamics of 125I-EGF endocytosis show that diabetic hepatocytes fail to down-regulate the surface EGF-R efficiently although the constant rate of internalization is not modified. Decreased down-regulation of EGF-R together with enhanced EGF endocytosis suggest a greater efficiency in EGF-R recycling in diabetic rat hepatocytes.

Effects of amiodarone therapy on thyroid iodine content as measured by x-ray fluorescence.

Thyroid iodine content (TIC) was measured by x-ray fluorescence in 68 patients who had received amiodarone treatment for varying intervals (1 g/week for 1-120 months). Thirty-six patients were euthyroid; the mean TIC of the patients (n = 15), who had been treated for less than 12 months was 30 +/- 19 (+/- SD) mg, twice the normal mean value (14.6 +/- 5.0 mg), and it was 39 +/- 17 mg in those (n = 16) who had been treated for 12-60 months and 29 +/- 6 mg in those (n = 5) who had been treated longer (greater than 60 months). Nineteen patients were hyperthyroid and had elevated TIC values. Of them, 6 patients had a goiter; their TIC (50 +/- 19 mg) was not significantly different from that of the hyperthyroid patients with no goiter (55 +/- 29 mg), but they became hyperthyroid more rapidly. Thirteen patients were hypothyroid; none had TIC values above the normal range, and it was below 2.5 mg in 5 patients. A sequential study was undertaken in 11 euthyroid patients who had no detectable antithyroid antibodies. TIC did not increase during treatment in 2 patients; both developed hypothyroidism, which was transient in 1 despite continuation of amiodarone treatment. The TIC initially increased during amiodarone treatment in the other 9 patients, leveling off at the end of the first year. The TIC rose well above the upper limit of the normal range in 4 patients, of whom 2 became hyperthyroid during the second year of treatment. TIC remained within the normal range in the other 5 patients, of whom 3 became hypothyroid after 12-24 months of treatment (1 subclinical, 2 overt). Although the TIC was significantly higher in the patients with hyperthyroidism than in the patients who remained euthyroid, the TIC test cannot be used to predict the occurrence of hyperthyroidism. The latter must be diagnosed on the basis of clinical symptoms and a frank elevation of serum thyroid hormone levels. Conversely, patients whose TIC values do not increase during treatment or remain within the normal range should be considered at risk for hypothyroidism.