VMAT-IGRT Hypofractionated Radiotherapy for Locally Advanced Thyroid Cancer in Resource-Limited Settings: A Retrospective Report from Bolivia

PURPOSE/OBJECTIVE(S)

This study evaluated the efficacy and safety of hypofractionated external beam irradiation with VMAT-IGRT in patients with locally advanced thyroid cancer (LATC) who are ineligible for surgery or I-131 in a resource-limited setting such as Bolivia.

MATERIALS/METHODS

Thirty-three patients were treated with H-VMAT-IGRT between August 2018 and November 2022. Axial CT images were acquired every 3 mm from the base of the skull to the middle of the chest. GTV was determined based on contrast-enhanced tumor on T1 MRI or CT scans. CTV 55 Gy at 2.75 Gy was defined based on visible residual tumor and included dissected nodal stations with pathologically positive nodes. CTV 44 at 2.2 Gy for non-dissected nodal stations with low risk of recurrence, we escalated the dose up to 60 Gy at 3 Gy for small tumors up to 20 cc. PTVs were created by adding a 0.3 cm margin around CTVs, with a reduced margin of minus 3-5 mm for critical organs such as esophagus, pharynx, and brachial plexus. Equivalent dose in 2Gy (EQD2 10-3) was reported for tumor control and OAR constraints. Acute toxicity was reported according to RTOG criteria, and response to treatment was assessed at baseline, end of treatment, and every third month thereafter.

RESULTS

The mean time since last follow-up was 24 months (r: 8-40). Patients were 80% female and 20% male. The mean age was 50 years (r: 29-72). Local recurrence was treated in 52% (13) of patients and LATC in 48% (12). Papillary carcinomas accounted for 68% of patients, followed by anaplastic (24%) and follicular (8%) carcinomas. Tumors were classified according to the AJCC classification. Of the patients treated for LATC, 25% were at stage II, 25% at stage III, 16.67% at stage IVA, and 33.33% at stage IVB. Among patients treated for local recurrence, the initial stage before progression was stage I in 61.5%, stage II in 30.8%, and stage IVA in 7.7%. The median PTV was 383.8 cc (r: 51.7 - 627.3) and the median CTV55 was 189.2 cc (r: 39.6 - 519.8). Grade 1 (10%), Grade 2 (90%) dysphagia, Grade 1 (40%), Grade 2 (60%) acute pharyngeal mucositis, and no Grade 3 acute toxicity were observed. No reports of chronic upper damage GI, 30% xerostomia G2. Two-year local control was 70% and overall survival was also 70%.

CONCLUSION

We suggest that reducing treatment duration while maintaining efficacy is particularly beneficial in resource-limited areas with a shortage of trained personnel and overburdened treatment centers. We report good local control rates with no detrimental effects on quality of life with hypofractionation. No evidence of delayed damage, such as spinal cord dysfunction, mandibular osteoradionecrosis, or brachial plexopathy, was noted. We emphasize the importance of using VMAT with IGRT for reliable and accurate daily treatment of the target area, while minimizing side effects. However, these results should be confirmed with a larger sample of patients.

Projecting the long-term benefits of single pill combination therapy for patients with hypertension in five countries

Background

It is well established that single pill combination (SPC) therapies have the potential to improve patient adherence versus multi-pill regimens, thereby improving blood pressure control and clinical outcomes in populations with hypertension.

Purpose

To develop a microsimulation model, capturing different treatment pathways, to project the impact on clinical outcomes of using single pill combination therapies for the management of hypertension in five countries (Italy, Russia, China, South Korea and Mexico).

Methods

The model was designed to project health outcomes between 2020 and 2030 for populations with hypertension managed according to four different treatment pathways: current treatment practices [CTP], single drug with dosage titration first then sequential addition of other agents [start low and go slow, SLGS], free choice combination with multiple pills [FCC] and combination therapy in the form of a single pill [SPC]. Model inputs were derived from Global Burden of Disease 2017 dataset, including demographics, health status/risk factors, transition probabilities and treatment attributes/healthcare utilization, and the model incorporated real-world challenges to healthcare delivery such as access to care, SBP measurement error, adherence and therapeutic inertia. Simulated outcomes of mortality, incidence of chronic kidney disease (CKD), stroke and ischemic heart disease (IHD), and disability-adjusted life years (DALYs) due to these conditions were estimated for population of 1,000,000 simulated patients for each treatment pathway and country.

Results

SPC therapy was projected to improve health outcomes over SLGS, FCC and CTP over 10 years in all five countries. SPC was forecast to reduce mortality by 5.4% (Italy), 4.9% (Russia), 4.5% (China), 2.3% (South Korea) and 3.6% (Mexico) versus CTP and showed greater projected reductions in mortality than SLGS and FCC. DALYs were projected to be reduced with SPC therapy by between 5.7% (Italy) and 2.2% (South Korea) compared with CTP and reductions in the incidence of clinical events were also projected with SPC therapy, with decreases in the range of 11.5% (Italy) to 4.9% (South Korea) versus CTP.

Conclusions

Ten-year projections of clinical outcomes associated with different anti-hypertensive treatment pathways in five countries indicated that both combination therapies (FCC and SPC) are likely to reduce the disease burden of hypertension compared with conventional management approaches, with SPC showing the greatest overall benefits due to improved adherence.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Sanofi, Gentilly, France

Ingestion of gastrolith mineralized matrix increases bone volume and tissue volume in mouse long bone fracture model

Purpose

Fracture healing often requires extended convalescence as the bony fragments consolidate into restored viable tissue for load-bearing. Development of interventions to improve healing remains a priority for orthopaedic research. The goal of this study was to evaluate the ability of a naturally occurring matrix of amorphous calcium carbonate to affect fracture healing in an uninstrumented long bone model.

Methods

Complete transverse fracture was induced in the fibula of mature mice, followed by daily gavage of crushed gastrolith from crayfish at doses of 0 (control), 1 (1 MG), and 5 (5 MG) mg/kg. At Day 17, bones and sera were harvested.

Results

Morphologically, the 1 MG treated group had greater bone volume (BV), and both 1 MG and 5 MG had greater tissue volume (TV) than control (p < 0.05), as determined by μCT; BV/TV and mineral density did not yield a statistical difference. Histologically, regional variations in mineralized matrix were evident in all specimens, indicating a broad continuum of healing within the callus. Among serum proteins, bone-specific alkaline phosphatase, indicative of active mineralization, was greater in 5 MG than control (p < 0.05). Sclerostin, an inhibitor of osteogenesis, was lower in 5 MG than control (p < 0.05), also suggestive of enhanced healing.

Conclusions

An increase in bone volume, tissue volume and cellular signaling for osteogenesis at 17 days following fibula fracture in this mouse model suggests that gastrolith treatment holds potential for improving fracture healing. Further study at subsequent time points is warranted to determine the extent to which the increase in callus size with gastrolith treatment may accelerate restoration of tissue integrity.

Prevalence of secondhand smoke exposure in asthmatic children at home and in the car: A cross-sectional study

OBJECTIVE

To compare secondhand smoke exposure (SHSe) prevalence at home and inside the car between asthmatic and non-asthmatic Portuguese children.

MATERIALS AND METHODS

This is a cross-sectional study that assessed children's SHSe in a representative sample of nine Portuguese cities. A validated self-reported questionnaire was administered to a random sample of 4th grade students during the school year of 2010/2011. The asthma prevalence was defined by the answers to three questions regarding asthma symptoms, medication and inhaler use. We performed chi-square tests and analysed frequencies, contingency tables, confidence intervals, and odd-ratios.

RESULTS

The self-reported questionnaire was administered to 3187 students. Asthma prevalence was 14.8% (472 students). Results showed that 32.3% of non-asthmatic children and 32.4% of asthmatic children were exposed to secondhand smoke as at least one of their household members smoked at home. The prevalence of parental smoking, smoking among fathers and smoking among mothers at home was also similar in both groups (asthmatic and non-asthmatic children). SHSe inside the car was 18.6% among non-asthmatic children and 17.9% among asthmatic children.

CONCLUSIONS

Asthmatic and non-asthmatic children were equally exposed to secondhand smoke, because no significant differences were found between the two groups concerning the prevalence of SHSe at home and inside the car. These findings highlight the need to include SHSe brief advice in paediatric asthma management.

Severe and acute loss of visual field in a young patient with optic disc drusen

CASE REPORT

We describe a case of a young patient with bilateral optic disc drusen, who in the course of 10 months, had a sudden visual field constriction in the right eye accompanied by moderate loss of vision, corresponding to the ophthalmological examination of changing from hidden to visible drusen.

DISCUSSION

The optic disk drusen are a fairly common disorder that is mainly considered as a benign disorder due to the low frequency of complications that appear during their course. This case shows how they can become a real problem in a short period of time.

The adult patient with native coarctation of the aorta: balloon angioplasty or primary stenting?

OBJECTIVE

To compare results of dilatation of native coarctation of the aorta with and without stent implantation.

DESIGN

Open, observational, non-randomised study.

PATIENTS

54 consecutive adult patients: 32 with balloon angioplasty alone (group 1) and 22 with stent placement (group 2).

INTERVENTIONS

Balloon dilatation from 1995 to 1997; dilatation with Palmaz stent placement from 1997 to 1999.

MAIN OUTCOME MEASURES

The primary end point was a composite index of failure including heart related death, a residual gradient of > 20 mm Hg, the need of reintervention, and aneurysm formation.

RESULTS

Peak systolic gradient (mean (SD)) was reduced both in group 1 (from 63.3 (22.8) to 10.7 (10.8) mm Hg, p < 0.001) and group 2 (from 63.9 (20.8) to 2.7 (4.3) mm Hg, p < 0.001), but Delta change was significantly greater in group 2. A residual gradient of > 10 mm Hg was shown to be the best cut off point to separate risk groups, representing a hazard ratio (HR) of 9.59 compared with a residual gradient of < or = 10 mm Hg (95% confidence interval (CI) 1.92 to 47.8). From multivariate Cox regression analysis, the only risk marker was the residual gradient (HR 8.9, 95% CI 1.2 to 63.0). The type of the coarctation and the use of stent were the factors associated with a residual gradient of < or = 10 mm Hg.

CONCLUSIONS

Mid term outcome in adult patients with native aortic coarctation receiving percutaneous treatment is strongly related to the immediate residual gradient. When treating these cases, efforts should be made to obtain gradients under 10 mm Hg, either by angioplasty alone or by placing a stent. Patients with discrete aortic coarctation have similar mid term results when the immediate residual gradient is < or = 10 mm Hg despite the implantation of a stent. To achieve these gradients, patients with hypoplastic isthmus or tubular coarctation should be treated with primary stenting. Further studies including exercise tests and non-invasive imaging are still needed before definitive conclusions can be drawn.

Surgical treatment for secundum atrial septal defects in patients >40 years old. A randomized clinical trial

We prospectively examined whether surgical treatment of secundum atrial septal defects (ASDs) in patients > or =40 years old improves their long-term clinical outcome. Surgical treatment of secundum ASDs in adults > 40 years old is a subject of controversy because of the perception of good long-term clinical outcomes in patients with unrepaired ASDs and the lack of data from randomized trials. We recruited 521 patients > 40 years old with secundum ASDs referred for treatment; 48 were excluded. Patients were randomly assigned to surgical closure (n = 232) or medical treatment (n = 241). The primary and secondary end points were a composite of major cardiovascular events (death, pulmonary embolism, major arrhythmic event, embolic cerebrovascular event, recurrent pulmonary infection, functional class deterioration or heart failure) and overall mortality, respectively. We assessed possible prognostic markers. The analysis was performed on an intention-to-treat basis. The median follow-up period was 7.3 years (range 2 to 13). The risk of having the primary end point was significantly higher in the medical group, which had a univariate hazards ratio of 1.99 (95% confidence interval [CI] 1.23 to 3.22) and a multivariate hazards ratio of 1.85 (95% CI 1.08 to 3.17). Although the survival analysis did not reveal differences in overall mortality between the surgical and medical treatments (hazards ratio 1.71, 95% CI 0.76 to 3.86), the multivariate analysis, adjusted by age at entry, mean pulmonary artery pressure and cardiac index, demonstrated significant differences between the study groups (hazards ratio 4.09, 95% CI 1.41 to 11.89). Surgical closure was superior to medical treatment in improving both the composite of major cardiovascular events and overall mortality in patients > 40 years old with secundum ASDs. This superiority was related to the mean pulmonary artery pressure, age at diagnosis and cardiac index. Because of the higher risk of morbidity and mortality, we believe that anatomic closure should always be attempted as the initial treatment for ASDs in adults > 40 years old with pulmonary artery systolic pressure < 70 mm Hg and a pulmonary/systemic output ratio > or =1.7. The operation must be performed as soon as possible, even if the symptoms or the hemodynamic impact seems to be minimal.

Nocturnal oxygen therapy in patients with the Eisenmenger syndrome

This prospective and controlled pilot study evaluates the long-term effects of nocturnal oxygen therapy (NOT) on exercise endurance, hematology variables, quality of life, and survival of 23 adult patients (mean age, 32 +/- 6 yr) with post-tricuspid congenital heart defects (ventricular septal defect = 10; patent ductus arteriosus = 13) and Eisenmenger Syndrome. All had pulmonary hypertension (mean pulmonary artery pressure = 88 +/- 20 mm Hg), severe hypoxemia (Pa(O(2)) = 44 +/- 5 mm Hg), and secondary erythrocytosis (hematocrit = 61.5 +/- 7%). Exercise endurance (6-min walk test = 380 +/- 88 m) was limited. In a random fashion, NOT was given to one group of patients (n = 12) but withheld from a comparable control group (n = 11). At 2 yr of close follow-up, two patients in the group of control patients, and three in the treatment group died. Mean survival estimates were similar in both groups (20.7 versus 20.8 mo; chi-square log-rank, 0.08; p = NS). Likewise, none of the hematology, exercise capacity, and quality of life variables examined showed statistically significant changes that were dependent on treatment regimen. We conclude that NOT does not modify the natural history of patients with advanced Eisenmenger Syndrome.

Characterization of syntenin, a syndecan-binding PDZ protein, as a component of cell adhesion sites and microfilaments

Syntenin is a PDZ protein that binds the cytoplasmic C-terminal FYA motif of the syndecans. Syntenin is widely expressed. In cell fractionation experiments, syntenin partitions between the cytosol and microsomes. Immunofluorescence microscopy localizes endogenous and epitope-tagged syntenin to cell adhesion sites, microfilaments, and the nucleus. Syntenin is composed of at least three domains. Both PDZ domains of syntenin are necessary to target reporter tags to the plasma membrane. The addition of a segment of 10 amino acids from the N-terminal domain of syntenin to these PDZ domains increases the localization of the tags to stress fibers and induces the formation of long, branching plasma membrane extensions. The addition of the complete N-terminal region, in contrast, reduces the localization of the tags to plasma membrane/adhesion sites and stress fibers, and reduces the morphotypical effects. Recombinant domains of syntenin with the highest plasma membrane localization display the lowest nuclear localization. Syndecan-1, E-cadherin, beta-catenin, and alpha-catenin colocalize with syntenin at cell-cell contacts in epithelial cells, and coimmunoprecipitate with syntenin from extracts of these cells. These results suggest a role for syntenin in the composition of adherens junctions and the regulation of plasma membrane dynamics, and imply a potential role for syntenin in nuclear processes.

[Influence of the pericardium in the pathophysiology of ventricular dysfunction in acute infarct of the right ventricle. Experimental study]

To obtain more information about the role of the pericardium in the setting of acute right ventricular infarction (ARVI) we studied the behaviour of the ventricular function curves (VFC) and the relationship of the ventricular end-diastolic pressures (R-VEDP-RV:LV) in two groups of dogs. Group A. (n = 12) Control (C), ARVI, Pericardiectomy (P). A parabolic behaviour of the C VFC was noted (r2 = 071) and it's flexion point (FP) was found in 13. +/- 2 mmHg. After the ARVI the right (R) VFC was shifted downwards and to the right and the FP was documented in 18 +/- 2 mmHg (p < 0.05) in relation to C VFC. After P the RVFC was displaced upwards and to the left in relation to ARVIC RVFC (p < 0.05). The C R-VEDP-RV:LV = 0.75 and only a trend to equalization after the ARVI and after P were noted (0.91, 0.84, respectively) (p = ns). Group B (n = 12). Control (C), P, ARVI. The RVFC after P was shifted up and to the left in relation to the C RVFC (p < 0.05) and the FP = 10 +/- 2 mmHg. After P in the setting of ARVI the RVFC was shifted downward and to the right in relation to P RVFC (p < 0.05). After P the R-VEDP-RV:LV = 0.45 and statistical significant equalized in the condition of ARVI without pericardium (0.95, p < 0.05).

CONCLUSION

Ours results support a partial restrictive role of the pericardium in the origin of the low cardiac output (LCO) in ARVI. Because, equalization of the R-VEDP-RV:LV is not only due to the restraining pericardial effect but is also due to right ventricular myocardial ischemia. The FP (18. +/- 2 mmHg) found seems to be the top value of RVEDP for volume infusion in experimental ARVI. Hemodynamic finding that could be useful in the preload volume management for humans with ARVI and LCO or systemic hypotension.

Plasmodium falciparum EBA-175 kDa protein peptides which bind to human red blood cells

Solid experimental evidence indicates that EBA-175 is used as a ligand by the Plasmodium falciparum merozoite to bind to human RBC, via different binding processing fragments. Using synthetic peptides and specific receptor-ligand interaction methodology, we have identified 6 high-activity binding sequences from the EBA-175 CAMP strain; peptide 1758 (KSYGTPDNIDKNMSLIHKHN), located in the so-called region I for which no binding activity has been reported before, peptides 1779 (NIDRIYDKNLLMIKEHILAI) and 1783 (HRNKKNDKLYRDEWWKVIKK), located in region II, in a sub-region known as 5' Cys F2, previously reported as being a binding region, and peptides 1814 (DRNSNTLHLKDYRNEENERH), 1815 (YTNQNINISQERDLQKHGFH) and 1818 (NNNFNNIPSRYNLYDKKLDL), in region III-V where antibodies inhibit merozoite invasion of erythrocytes. The affinity constants were between 60 and 180 nM and the critical amino acids involved in the binding were identified. The binding of these peptides to enzyme-treated RBC was analysed; binding of peptide 1814, located in the III-V region, was found to be sialic acid dependent. Some of these high binding peptides were able to inhibit in vitro merozoite invasion and to block the binding of recombinant RII-EBA to RBC. Several of these peptides are located in regions recognized by protective immune clusters of merozoites (ICMs) eluted antibodies.

The adult patient with Ebstein anomaly. Outcome in 72 unoperated patients

Knowledge of the long-term outcome in unoperated adult patients with Ebstein anomaly is limited, and the therapeutic approach is still controversial. We studied unoperated adult patients with Ebstein anomaly to define the patterns of presentation, anatomic characteristics, outcome, and predictive factors for survival. Seventy-two unoperated survivors of Ebstein anomaly aged over 25 years attended from 1972 to 1997 were reviewed and followed-up from 1.6 to 22.0 years. Patients were classified in 3 groups of severity according to the echocardiographic appearance of the septal leaflet attachment of tricuspid valve. The mean age at diagnosis was 23.9 +/- 10.4 years, and the most common clinical presentation was an arrhythmic event (51.4%). There were 30 (42%) deaths, including 6 from arrhythmia, 12 related to heart failure, 7 sudden, 2 unrelated, and 3 unascertained. According to Cox regression analysis, predictors of cardiac-related death included age at diagnosis (hazard ratio 0.89 for each year of age, 95% confidence intervals CI[ 0.84-0.94), male sex (3.93, 95% CI, 1.50-10.29), degree of echocardiographic severity (3.34, 95% CI, 1.78-6.24), and cardiothoracic ratio > or = 0.65 (3.57, 95% CI, 1.15-11.03). During follow-up, morbidity was mainly related to arrhythmia and refractory late hemodynamic deterioration. The magnitude of tricuspid regurgitation, cyanosis, and the New York Heart Association (NYHA) functional class at time zero were significant risk factors according to the univariate analysis, but not after multivariable confrontation. The results of this study suggest that pattern of presentation, clinical course, and prognosis of unoperated adult patients with Ebstein anomaly are influenced by several factors. Although the initial symptoms are usually mild and commonly related to supraventricular arrhythmias, these are not associated with the long-term outcome. The severity of the morbid anatomy was the main determinant of survival only in extreme cases, but not in those with mild or moderate deformations, which are more common in adults. Other independent risk factors such as cardiothoracic ratio, sex, age at diagnosis, and the echocardiographic evaluation may help to determine the therapeutic approach. Adult patients with Ebstein anomaly should not be considered as a simple low-risk group.

Pericardium-covered stent for septal myocardial ablation in hypertrophic obstructive cardiomyopathy

This report describes a patient with severe hypertrophic obstructive cardiomyopathy in New York Heart Association functional class III. Complete reduction of left ventricular outflow tract gradient was achieved by the selective occlusion of three target septal arteries with a pericardium-covered stent. The patient's in-hospital course was uneventful and has improved to functional class I.

Effect of body position changes on pulmonary gas exchange in Eisenmenger's syndrome

Preliminary studies on sleep of patients with congenital heart disease and Eisenmenger's syndrome (ES) at our institution demonstrated nocturnal worsening arterial unsaturation, which appeared to be a body position-related phenomenon. To investigate the potential effect of body position on gas exchange in ES, we carried out a prospective study of 28 patients (mean age, 34.8 +/- 11.7 yr) with established ES due to congenital heart disease. In every patient, arterial blood gases were performed during both sitting and supine positions under three different conditions: room air, while breathing 100% oxygen, and after breathing oxygen at a flow rate of 3 L/min through nasal prongs. Alveolar oxygen pressure (PaO2) for the calculation of alveolar-arterial oxygen tension differences (AaPO2) was derived from the alveolar gas equation using PaCO2 and assuming R = 1. We used paired t test, repeated-measures two-way ANOVA with Bonferroni's test, and regression analysis. From sitting to supine position on room air, there was a significant decrease in PaO2 (from 52.5 +/- 7.5 to 47.5 +/- 5.5 mm Hg; p < 0. 001) and SaO2 (from 86.7 +/- 4.6 to 83.3 +/- 4.9%; p < 0.001), both of which were corrected by nasal O2 (to 68.2 +/- 21 mm Hg and to 92 +/- 4%, respectively, p < 0.005). PaCO2 and pH remained unchanged. The magnitude of the change in PaO2 correlated with the change in AaPO2 on room air (r = 0.77; p < 0.01) but not with the change in AaPO2 on 100% oxygen. It is concluded that in adult patients with ES there is a significant decrease in PaO2 and SaO2 when they change from the sitting to the supine position. A ventilation-perfusion (V/Q) distribution abnormality and/or a diffusion limitation phenomenon rather than an increase in true shunt may be the mechanisms responsible for this finding. The response to nasal O 2 we observed warrants a trial with long-term nocturnal oxygen therapy in these patients.

Circadian studies of autonomic nervous balance in patients with fibromyalgia: a heart rate variability analysis

OBJECTIVE

To determine the accumulated 24-hour cardiovascular autonomic modulation and its circadian variations in patients with fibromyalgia, by means of heart rate variability analysis.

METHODS

Thirty patients with fibromyalgia and 30 age- and sex-matched controls were studied prospectively. Assessments included a 24-hour ambulatory recording of heart rate variability, time-domain analysis of the accumulated 24-hour R-R interval variations, and power spectral analysis to determine the sympatho/ vagal balance at different hours (calculated as the power spectral density of the low-frequency [0.04-0.15-Hz] sympathetic band divided by the power of the high-frequency [0.15-0.50-Hz] parasympathetic band).

RESULTS

Fibromyalgia patients had diminished accumulated 24-hour heart rate variability, manifested by a decreased standard deviation of all R-R intervals (mean +/- SD 126 +/- 35 ms, versus 150 +/- 33 ms in controls; P = 0.008) and a decreased ratio of pairs of adjacent R-R intervals differing by >50 ms (mean +/- SD 12.0 +/- 9.0% versus 20.1 +/- 18.0%; P = 0.031). Patients lost the circadian variations of sympatho/vagal balance, with nocturnal values significantly higher than those of controls at time 0 (mean +/- SD 3.5 +/- 3.2 versus 1.2 +/- 1.0; P = 0.027) and at 3 hours (3.3 +/- 3.0 versus 1.6 +/- 1.4; P = 0.01).

CONCLUSION

Individuals with fibromyalgia have diminished 24-hour heart rate variability due to an increased nocturnal predominance of the low-frequency band oscillations consistent with an exaggerated sympathetic modulation of the sinus node. This abnormal chronobiology could explain the sleep disturbances and fatigue that occur in this syndrome. Spectral analysis of heart rate variability may be a useful test to identify fibromyalgia patients who have dysautonomia.

Relationship between the site of a myocardial infarction and signal-averaged electrocardiogram indices

We evaluated the relationship between the site of a myocardial infarction (MI) and signal-averaged electrocardiogram (SAECG) indices in both time-domain (TDA) and spectral turbulence (STA) analyses, and their implications in the prediction of infarct-related artery (IRA) patency, in 114 survivors of a first MI. They were divided into two groups based on MI location (57 anterior and 57 inferior). Patients with bundle branch block were not included. Fifty patients had been treated with thrombolytic therapy (TT). The STA was done in both XYZ-leads and in vector magnitude. Forty patients had an abnormal SAECG in TDA and 37 in STA, but only 22 (19%) in both (71% of agreement, kappa=0.35). Fifty-four patients (47%) had an occluded IRA. The best predictors from multivariate analysis of having an occluded IRA in the inferior MI group were: an abnormal Y-lead in STA (odds ratio 4.9; P=0.005); an abnormal RMS40 in TDA (odds ratio, 4.8; P=0.02); absence of TT (odds ratio, 9.15; P=0.001). Conversely, in the anterior MI group they were: an abnormal SAECG in TDA (odds ratio 6.83; P=0.005); absence of TT (odds ratio, 4.3; P=0.02). The multivariate receiver operator characteristic curves clearly showed the effect of MI location on the SAECG indices. This study suggests that the myocardial infarction site is an important factor for the variability and poor concordance between TDA and STA. Such differences may alter the predictive accuracy of SAECG. TDA and STA should be complementary methods, and the exploration in each orthogonal lead appears to be better than in vector magnitude.

[Analysis of reperfusion by thrombolysis of the artery responsible for acute myocardial infarction]

OBJECTIVE

To analyze the role of the culprit coronary artery in myocardial infarction, its evolution and mortality. And to correlate with clinical criteria of reperfussion.

MATERIALS AND METHODS

We included patients with clinical diagnosis of acute myocardial infarction (MI) treated with thrombolytic therapy, and coronariography. We used the TIMI study angiographic scale to evaluate the level of permeability of the culprit artery.

RESULTS

Of 473 patients with of acute MI; coronariography was made in 377. The most frequent culprit vessel was anterior descending artery in 168 patients (45%) and right coronary artery in 139 patients (36%). In 276 patients the culprit vessel was permeable (73%). Of them in 30 patients, had TIMI 1 alterations, TIMI 2 in 97 patients, had TIMI 3 in 148 patients, only 102 patients had TIMI 0. In anterior MI the most frequent reperfussion arrhythmia was ventricular ectopic beats followed by slow ventricular tachycardia and ventricular tachycardia in 54%, ventricular fibrillation was observed only in six patients, of whom TIMI scale was 2 and 3 in five patients. In inferior MI, ventricular ectopic beats and slow ventricular tachycardia was seen in 25% of patients. In patients with permeable culprit artery we observed significant depression of ST segment, (159 patients, 42%), and significant increase in CK-MB levels, seen in 191 patients (51%). In the group of patients with total occlusion of the culprit artery, twenty-one (30%) had left ventricular disfuntion, and only six of them were in cardiogenic shock. In the group of patients with permeable culprit artery only two percent had cardiogenic shock. Therefore the analysis of the clinical evolution is the maia marker to take into consideration to send patients to early coronary arteriography with the objective to look for other therapeutic alternatives.

Comparison of prevalence of anti-hepatitis C virus antibodies in differing South American populations

Very little is known about the distribution of hepatitis C virus (HCV) within South America. To assess the exposure of the general population to this virus, a number of sera obtained from three distinct geographical and racial groups were screened using a combination of immunoassays. Initial screening was undertaken with an inhouse immunoassay (core-ELISA) using synthetic peptides based on the N-terminus of the HCV core protein. Sera which were repeatedly positive by core-ELISA were also assessed using a commercial third-generation assay. The highest prevalence rate (2.3%) was seen in sera taken from the Tumaco region of Colombia. Lower rates were found in sera taken from La T, Ecuador (0.7%) and Las Majadas, Venezuela (0.7%). This indicates significantly different prevalence in different racial and geographical groups within the region.

Antidepressant effect of transdermal nicotine patches in nonsmoking patients with major depression

BACKGROUND

A high frequency of cigarette smoking has been reported among individuals with major depression. In a previous study, transdermal nicotine produced short-term improvement in the mood of depressed patients. This study was undertaken to determine the effects of 4 days' administration of transdermal nicotine on mood in nonsmoking patients with major depression.

METHOD

The effects of nicotine patches (17.5 mg) on 12 nonmedicated outpatients with major depression (DSM-III-R) were studied for 4 continuous days. Patients had to score 18 points or more on the Hamilton Rating Scale for Depression (HAM-D) (21 items) for admission into the study. The HAM-D (10 items), a visual analog scale, and a side effects scale were scored daily during the trial (baseline, 4 days of nicotine patches, and 4 days of follow-up).

RESULTS

Two patients dropped out of the study owing to nausea and vomiting. Results of the visual analog scale and HAM-D (10 items) showed a significant (p < .01) improvement in depression after the second day of nicotine patches. Patients relapsed 3 or 4 days after the last nicotine dose. The side effects observed were an increase in saliva production, nausea, loss of appetite, and mild insomnia.

CONCLUSION

Nicotine patches produced short-term improvement of depression with minor side effects. Because of nicotine's high risk to health, nicotine patches are not recommended for clinical use in depression. Analogue drugs may be developed in the future that may help improve depression without the risk of other major health problems.

Endemic fluorosis in San Luis Potosi, Mexico. I. Identification of risk factors associated with human exposure to fluoride

In order to identify risk factors associated with human exposure to fluoride in San Luis Potosi (SLP), Mexico, a biochemical and epidemiological study was carried out in 1992. Results from the analysis of fluoride sources showed that 61% of tap water samples had fluoride levels above the optimal level of 0.7-1.2 ppm. The levels were higher after boiling. In bottled water, fluoride levels ranged from 0.33 to 6.97 ppm. These sources are important since in SLP 82% of the children drink tap water, 31% also drink bottled water, 92% prepare their food with tap water, 44% boiled all the drinking water, and 91% used infant formula reconstituted with boiled water. The prevalence and severity of dental fluorosis in children (11-13 years old) increased as the concentration of water fluoride increased. At levels of fluoride in water lower than 0.7 ppm a prevalence of 69% was found for total dental fluorosis, whereas at levels of fluoride in water higher than 2.0 ppm a prevalence of 98% was found. In the same children, fluoride levels in urine were quantified. The levels increased as the concentration of water fluoride increased. Regressional analysis showed an increment of 0.54 ppm (P < 0.0001) of fluoride in urine for each ppm of fluoride in water. Fluoride urinary levels were higher in samples collected during the afternoon (1800) when compared with sample collected during the morning (1100). Taking together all these results, three risk factors for human exposure to fluoride in SLP can be identified: ambient temperature, boiled water, and food preparation with boiled water. These factors explain the prevalence of dental fluorosis in SLP.

Characterization of fat-storing cell lines derived from normal and CCl4-cirrhotic livers. Differences in the production of interleukin-6

Liver fat-storing cells (FSC) play an important role in collagen deposition. During the induction of liver cirrhosis, FSC lose their fat droplets, acquire an actin-rich cytoskeleton and transform into myofibroblasts. Myofibroblasts have been associated with increased collagen production in cirrhotic livers. Cultured FSC resemble myofibroblasts. However, it is not known whether regulation of collagen gene expression is similar in FSC obtained from normal or cirrhotic livers. In this communication, we describe the characterization of two fat-storing cell lines, one from normal (NFSC) and one from CCl4-cirrhotic liver (CFSC), obtained after spontaneous immortalization in culture. We studied the effect of serum and various growth factors on cell proliferation. We determined the production of collagen and fibronectin and we analyzed the presence of mRNA transcripts of collagens type I, III, and IV, fibronectin laminin, transforming growth factor-beta and interleukin-6. We found that CFSC have a greater serum-dependency than NFSC. NFSC grow with a mixture of insulin and epidermal growth factor, whereas CFSC proliferate only with platelet-derived growth factor. Although we did not find significant differences in the expression of mRNAs for collagen type I, fibronectin and transforming growth factor-beta, collagen and fibronectin synthesis was increased 2- and 1.5-fold respectively. NFSC contained 1.6- and 2.0-fold more type III collagen and laminin mRNAs, respectively, than CFSC. Neither cell line expressed type IV collagen mRNA. NFSC but not CFSC produced interleukin-6. These results suggest that, except for the lack of transcripts of collagen type IV, both cell lines resemble primary cultures of FSC. However, significant differences in cell proliferation and interleukin-6 production between the two cell lines were found. We suggest that these cell lines could be useful tools to study possible differences in regulation of matrix production by FSC.

Retention indices by wide-bore capillary gas chromatography with nitrogen-phosphorus detection

The use of wide-bore capillary columns in gas chromatography (GC) with nitrogen-phosphorus detectors (NPD) is gaining popularity in the toxicology laboratory. Though the preferred method to achieve reproducible results and to make interlaboratory comparisons of GC data is by retention index (RI), the selectivity of the NPD has relegated its users to calculations of relative retention time. The present study utilizes a set of drugs as reference standards under temperature programmed conditions and presents a unique method of RI calculation. RI calculations are highly reproducible with this technique (day-to-day variations range from 0.3 to 3.4 RI units) and are comparable to packed column, FID generated reference data. A program, written in Basic, calculates RI values based on daily injections of the reference standards and searches a library of over 100 basic and acidic drugs.

Neonatal loss. What can be done to ease parents' grief

Healthcare professionals have an important role in helping grieving parents cope with a neonatal loss. Physicians need to be professionally prepared to deal with such a situation, which includes knowing how to refer the parents to community support systems and anticipating and being prepared for a variety of emotional responses. Suggestions based on personal experience are offered for dealing with bereaved parents during this complex and difficult time.