Detection of blaCTX-M-15 in an integrative and conjugative element in four extensively drug-resistant Haemophilus parainfluenzae strains causing urethritis

Haemophilus parainfluenzae is a commensal organism with rising numbers of multidrug-resistant (MDR) strains. This pathogen is of increasing clinical relevance in urogenital infection. The aim of this work was to identify and characterise the molecular mechanisms of resistance associated with four cephalosporin-resistant H. parainfluenzae strains collected from patients with urethritis. Antimicrobial resistance was determined by microdilution following European Committee on Antimicrobial Susceptibility Testing criteria. Strains were then analysed by whole-genome sequencing to determine clonal relationship and the molecular basis of antimicrobial resistance. Finally, a phylogenetic analysis was performed on all urogenital MDR strains of H. parainfluenzae previously isolated in our hospital. All strains were resistant to β-lactams, macrolides, tetracycline, fluoroquinolones, chloramphenicol, cotrimoxazole, and aminoglycosides. The resistance profile was compatible with the presence of an extended-spectrum β-lactamase (ESBL). Whole-genome sequencing detected blaCTX-M-15 that conferred high minimum inhibitory concentrations to cephalosporins in two novel integrative and conjugative elements (ICEHpaHUB6 and ICEHpaHUB7) that also harboured a blaTEM-1 β-lactamase. This study shows a novel blaCTX-M-15 ESBL carried in an integrative conjugative element in four extensively drug-resistant H. parainfluenzae strains. This resistance determinant could be transmitted to other sexually transmitted pathogens and this is a cause for concern.

ThyroidPrint®: clinical utility for indeterminate thyroid cytology

Molecular testing contributes to improving the diagnosis of indeterminate thyroid nodules (ITNs). ThyroidPrint® is a ten-gene classifier aimed to rule out malignancy in ITN. Post-validation studies are necessary to determine the real-world clinical benefit of ThyroidPrint® in patients with ITN. A single-center, prospective, noninterventional clinical utility study was performed, analyzing the impact of ThyroidPrint® in the physicians' clinical decisions for ITN. Demographics, nodule characteristics, benign call rates (BCRs), and surgical outcomes were measured. Histopathological data were collected from surgical biopsies of resected nodules. Of 1272 fine-needle aspirations, 109 (8.6%) were Bethesda III and 135 (10.6%) were Bethesda IV. Molecular testing was performed in 155 of 244 ITN (63.5%), of which 104 were classified as benign (BCR of 67.1%). After a median follow-up of 15 months, 103 of 104 (99.0%) patients with a benign ThyroidPrint® remained under surveillance and one patient underwent surgery which was a follicular adenoma. Surgery was performed in all 51 patients with a suspicious for malignancy as per ThyroidPrint® result and in 56 patients who did not undergo testing, with a rate of malignancy of 70.6% and 32.1%, respectively. A higher BCR was observed in follicular lesion of undetermined significance (87%) compared to atypia of undetermined significance (58%) (P < 0.05). False-positive cases included four benign follicular nodules and six follicular and four oncocytic adenomas. Our results show that, physicians chose active surveillance instead of diagnostic surgery in all patients with a benign ThyroidPrint® result, reducing the need for diagnostic surgery in 67% of patients with preoperative diagnosis of ITN.

Clinical Update on Congenital Adrenal Hyperplasia: Recommendations from a Multidisciplinary Adrenal Program

Congenital adrenal hyperplasia (CAH) is a common genetic disorder in endocrinology, especially its milder clinical presentation, often caused by a partial or total deficiency of the 21-hydroxylase enzyme located in the adrenal cortex. CAH is characterized by the overproduction of androgen, along with variable degrees of cortisol and aldosterone deficiency. The age at diagnosis can provide some information about underlying mutations, with those diagnosed at birth/early infancy more likely to have severe enzymatic defects, which may include adrenal insufficiency, sexual development disorders, short stature in adulthood, hirsutism, and a higher risk for metabolic syndrome and infertility. Non-classic CAH, a milder form of CAH, is usually manifested later in life and is a common differential diagnosis of Polycystic Ovary Syndrome and should be actively evaluated during initial studies of clinical or biochemical hyperandrogenism. The main goals of CAH treatment are hormone supplementation for severe cases, controlling adrenal androgen overproduction to minimize long-term side effects, managing fertility and genetic counseling, and optimizing patients' quality of life.

Clinical and histopathological features of follicular thyroid cancer in Chile

Objective

Follicular thyroid carcinoma (FTC) is less frequent but has a worse prognosis than papillary carcinoma. The available evidence on pre-operative characteristics of FTC is controversial. Our objective was to characterize the clinical, ultrasound and histopathological presentation of FTC patients treated Chile.

Subjects and methods

Retrospective analysis of 97 patients treated for FTC in 6 large centers in Chile. We analyzed their ultrasonographic features and classified the nodules according to ATA risk of malignancy and TI-RADS score, as well as the cytological findings according to the Bethesda system. We described their clinical and histopathological findings at diagnosis and classified their risk of recurrence and mortality according to ATA 2015 recurrence risk category and the eighth edition of the AJCC/UICC staging system, respectively.

Results

Median age was 48 years and 73.2% were females. The median diameter was 38.8 mm; only 9.5% of them were microtumors. According to ATA risk of malignancy, 86% of the nodules were low or intermediate suspicious, while 78% were category 3 or 4A nodules according to the TI-RADS. Regarding the Bethesda system, 65.9% had indeterminate cytology (20.6% category III and 45.3% category IV). At histological examination, most were minimally-invasive and angio-invasive tumors with less than 4 foci (54.7% and 28.4% respectively). More than 90% of FTC were unifocal and there was no lymphovascular or extrathyroidal invasion or lymph node involvement. Four patients (4.1%) had distant metastases at diagnosis. Most patients (95%) had stage I or II disease according to the AJCC/UICC staging system, while the risk of recurrence was low at 51.5% when using the ATA risk of recurrence scale.

Conclusion

At diagnosis, most FTCs were nodules of low or intermediate suspicion at ultrasound, nearly two thirds had indeterminate cytology according to the Bethesda system, and nearly 50% of them were of low risk of recurrence.

Synchronous bilateral laparoscopic adrenalectomy: Surgical technique and perioperative results of a 13-years' experience

INTRODUCTION AND OBJECTIVES

Laparoscopic surgery is the standard approach for the treatment of adrenal glands. Bilateral synchronous adrenalectomy is rarely performed, and evidence about this procedure is limited. Our objective is to report our 13-year experience with synchronous laparoscopic bilateral adrenalectomy, evaluating its feasibility, safety, and perioperative outcomes.

PATIENTS AND METHODS

A total of 23 consecutive patients undergoing synchronous bilateral laparoscopic adrenalectomy between 2007 and 2020 in a single academic center were included. Variables evaluated were operative time, estimated blood loss, conversion to open surgery, postoperative complications, mortality, and postoperative length of stay.

RESULTS

Mean operative time was 189.3 ± 48.9 min. Mean estimated blood loss was 163.0 ± 201.3 mL. There were no conversions to open surgery. Five patients had postoperative complications, three of those were major. No patient died in the perioperative period. Median postoperative length of stay was three days (range 1-30). At pathology analysis, 15 patients had bilateral adrenal hyperplasia, 2 unilateral adrenal hyperplasia and a contralateral benign tumor, 1 unilateral adrenal hyperplasia and a normal contralateral gland, 1 unilateral adenoma, 3 bilateral pheochromocytomas and 1 bilateral myelolipoma.

CONCLUSION

Synchronous bilateral laparoscopic adrenalectomy is a feasible and safe technique. A multidisciplinary and experienced team involving anesthesiologists and endocrinologists is required.

Discriminative Capacity of CT Volumetry to Identify Autonomous Cortisol Secretion in Incidental Adrenal Adenomas

CONTEXT

Incidentally discovered adrenal adenomas are common. Assessment for possible autonomous cortisol excess (ACS) is warranted for all adrenal adenomas, given the association with increased cardiometabolic disease.

OBJECTIVE

To evaluate the discriminatory capacity of 3-dimensional volumetry on computed tomography (CT) to identify ACS.

METHODS

Two radiologists, blinded to hormonal levels, prospectively analyzed CT images of 149 adult patients with unilateral, incidentally discovered, adrenal adenomas. Diameter and volumetry of the adenoma, volumetry of the contralateral adrenal gland, and the adenoma volume-to-contralateral gland volume (AV/CV) ratio were measured. ACS was defined as cortisol ≥ 1.8 mcg/dL after 1-mg dexamethasone suppression test (DST) and a morning ACTH ≤ 15. pg/mL.

RESULTS

We observed that ACS was diagnosed in 35 (23.4%) patients. Cortisol post-DST was positively correlated with adenoma diameter and volume, and inversely correlated with contralateral adrenal gland volume. Cortisol post-DST was positively correlated with the AV/CV ratio (r = 0.46, P < 0.001) and ACTH was inversely correlated (r = -0.28, P < 0.001). The AV/CV ratio displayed the highest odds ratio (1.40; 95% CI, 1.18-1.65) and area under curve (0.91; 95% CI, 0.86-0.96) for predicting ACS. An AV/CV ratio ≥ 1 (48% of the cohort) had a sensitivity of 97% and a specificity of 70% to identify ACS.

CONCLUSION

CT volumetry of adrenal adenomas and contralateral adrenal glands has a high discriminatory capacity to identify ACS. The combination of this simple and low-cost radiological phenotyping can supplement biochemical testing to substantially improve the identification of ACS.

Warthin-like and classic papillary thyroid cancer have similar clinical presentation and prognosis

Objective

Warthin-like papillary thyroid cancer (WL-PTC) is an uncommon variant of PTC, usually associated with lymphocytic thyroiditis. Scarce evidence suggests that WL-PTC has similar clinical presentation to classic PTC (C-PTC), with no studies comparing risks of recurrence and response to treatment between both variants. Our objective was to describe the clinical presentation and prognosis of WL-PTC and compare it to C-PTC.

Methods

Retrospective analysis of a prospective cohort, including 370 (96%) patients with C-PTC and 17 (4%) with WL-PTC, consecutively treated with total thyroidectomy with or without RAI, followed for at least 6 months. We compared clinical presentation, risk of mortality and recurrence, as well as response to treatment between both variants.

Results

Of the total cohort: 317 (82%) female, 38 ± 13.5 years, median follow-up 4 years (0.5-28.5); most of them stage I and low/intermediate risk of recurrence. We found no differences regarding clinical-pathological data and risk of recurrence. WL-PTC was associated with a higher rate of anti-thyroglobulin antibodies (TgAb) (65% vs. 36%, p = 0.016) and lymphocytic thyroiditis (59% vs. 34%, p = 0.03). The rates of biochemical and structural incomplete responses were similar in both variants. WL-PTC had a lower rate of excellent response (23% vs. 54%, p = 0.01), which became non-significant when performing analysis by TgAb presence (50% vs. 67%, p = NS).

Conclusion

WL-CPT and C-CPT have similar clinical presentation and rate of recurrence. The lower rate of excellent response to treatment in WL-PTC is due to a higher frequency of TgAb. WL-PCT should not be considered an aggressive variant of PTC.

Clinical Presentation and Perioperative Management of Pheochromocytomas and Paragangliomas: A 4-Decade Experience

Purpose

Latin American reports on pheochromocytomas and paragangliomas (PPGLs) are scarce. Recent studies demonstrate changes in clinical presentation and management of these patients. Herein, we assessed the main characteristics of PPGL patients in our academic center over the past 4 decades.

Methods

Demographic, clinical, biochemical, and perioperative data from 105 PPGL patients were retrospectively and prospectively collected over the 1980–2019 period. Data were organized into 4 periods by decade.

Results

Age at diagnosis, gender, tumor size and percentage of bilaterality, percentage of paragangliomas, and metastases remained stable across the 4 decades. The proportion of genetic testing and incidentalomas increased in recent decades (all P < 0.001). Therefore, we compared PPGLs diagnosed as incidentalomas (36%) with those clinically suspected (64%). Incidentalomas had fewer adrenergic symptoms (38 vs. 62%; P < 0.001) and lower rates of hypertension (64% vs. 80%; P = 0.01) and hypertensive crisis (28% vs. 44%; P = 0.02); also, they had lower functionality (79% vs. 100%; P = 0.01) and lower catecholamines levels (8.4-fold vs. 12.5-fold above upper cutoffs; P = 0.04). Regarding management of all PPGLs over the decades, we observed significant increases in both perioperative doxazosin dose (P = 0.003) and laparoscopic approach rates (P < 0.001), along with a decrease in the length of hospital stays (P = 0.007).

Conclusions

We observed a change in the clinical presentation of PPGL in recent decades, with a marked increase in incidental cases and milder symptoms. The implementation of a multidisciplinary program for adrenal disorders in our institution has translated into more timely diagnoses, more genetic testing, and improvements in perioperative management.

Cholestasis secondary to hyperthyroidism in Graves' disease. Report of one case

Hyperthyroidism can induce elevation in several liver function tests including aminotransferases, alkaline phosphatases and, less frequently, serum bilirubin. These alterations are usually mild and asymptomatic. We report a 26 year-old male presenting with palpitations, progressive jaundice, choluria and generalized itching. Laboratory tests were compatible with hyperthyroidism and a mild elevation of bilirubin, alkaline phosphatases and gamma glutamyl transpeptidase. A liver biopsy showed portal hepatitis with canalicular cholestasis. The patient was treated temporarily with glucocorticoids, cholestyramine and betablockade. Thereafter, he was treated with radioactive iodine, after which serum bilirubin decreased steadily until normalization in ten weeks.

Sarcoid-like granulomatous myositis-associated hypercalcemia. An infrequent case to consider

PTH-independent hypercalcemia due to granulomatous disease is well-documented and sarcoidosis is the most characteristic disease, although there are others. We describe a case of sarcoid-like granulomatous myositis. An 87-year-old man was referred with tetraparesis and hypercalcemia (albumin-corrected calcium of 13.4 mg/dl) following a trip to the Caribbean. The evaluation showed a suppressed PTH, 25-hydroxy vitamin D of 7.5 ng/ml, 18F-FDG PET/CT showed markedly increased uptake in intercostal, back, shoulder, buttock and thigh muscles and a deltoid biopsy confirmed extensive granulomatous myositis. He was prescribed glucocorticoids which resulted in normalized plasma calcium levels and complete recovery from tetraparesis. Sarcoid-like granulomatous myositis should be incorporated into the differential diagnosis of PTH-independent hypercalcemia, especially in the absence of clinical features of sarcoidosis and with special emphasis on the use of 18F-FDG PET/CT to ensure a correct approach.

MCCB cognitive profile in Spanish first episode schizophrenia patients

The objective of the study was to examine the cognitive profile of Spanish patients with a first episode of schizophrenia (FESz) and to compare that to the profile of patients with a chronic schizophrenia (CSz) and non-psychiatric (NP) control subjects. The study included 106 FESz, 293 CSz, and 210 NP, assessed with the Spanish version of the MATRICS Consensus Cognitive Battery (MCCB). The MCCB cognitive profile in a Spanish sample of FESz was similar to the cognitive profile of CSz with some discrepancies in select domains. The scores of both patient samples were about 1-2 SD below the scores of non-psychiatric control subjects.

In properly selected patients with differentiated thyroid cancer, antithyroglobulin antibodies decline after thyroidectomy and their sole presence should not be an indication for radioiodine ablation

OBJECTIVE

Our objective was to evaluate the trend of antithyroglobulin antibodies (TgAb) during follow-up of patients with differentiated thyroid cancer (DTC) treated without RAI, as well as their role in the risk of recurrence.

SUBJECTS AND METHODS

This was a prospective, descriptive study. A total of 152 consecutive patients with DTC treated in a single institution undergoing total thyroidectomy without RAI and followed for a median of 2.3 years (0.5-10.3) were divided in two groups: TgAb(-) (n = 111) and TgAb(+) (n = 41). Patients were classified according to AJCC 7th and 8th editions, as well as to their risk of recurrence and response to treatment categories.

RESULTS

Both groups, TgAb(-) and TgAb(+), were similar regarding patient and tumor characteristics. At the end of follow-up, 90 (59.2%), 57 (37.5%), 3 (2%) and 2 (1.3%) patients achieved excellent, indeterminate, biochemically incomplete and structurally incomplete response, respectively. The risk of structural recurrence was similar in both groups (TgAb[-] 0.9% vs. TgAb[+] 2.4%, p = 0.46). In the TgAb(+) group, TgAb became negative in 10 (24.4%), decreased ≥ 50% without negativization in 25 (60.9%), decreased < 50% in 4 (9.8%) and remained stable or increased in 2 (4.9%) cases. The only incomplete structural response had increasing TgAb during follow-up.

CONCLUSIONS

In properly selected patients with DTC, TgAb concentration immediately after total thyroidectomy should not mandate RAI ablation, and their trend during follow-up may impact the risk of recurrence.

The Aldosterone/Renin Ratio Predicts Cardiometabolic Disorders in Subjects Without Classic Primary Aldosteronism

BACKGROUND

Aldosterone has been linked with obesity, metabolic syndrome (MetS), pro-inflammatory, and prothrombotic states; however, most studies relate these indicators with primary aldosteronism (PA), excluding non-PA patients.

OBJECTIVE

To determine whether aldosterone, renin, or the plasma aldosterone/renin ratio (ARR) are associated with metabolic disorders and inflammatory/vascular biomarkers in a non-PA population.

METHODS

We studied 275 patients including adolescents and adults of both genders and measured plasma and urinary aldosterone and determined the plasma renin activity. In all subjects, the presence of MetS was determined according to Adult Treatment Panel III. Renal, vascular, inflammatory, and mineralocorticoid activity biomarkers were evaluated.

RESULTS

The ARR correlated with the number of variables of MetS (r = 0.191, P = 0.002), body mass index (BMI; r = 0.136, P = 0.026), systolic blood pressure (r = 0.183, P = 0.002), diastolic blood pressure (r = 0.1917, P = 0.0014), potassium excreted fraction (r = 0.174, P = 0.004), low-density lipoprotein (r = 0.156, P = 0.01), plasminogen activator inhibitor type 1 (r = 0.158, P = 0.009), microalbuminuria (r = 0.136, P = 0.029), and leptin (r = 0.142, P = 0.019). In a linear regression model adjusted by age, BMI, and gender, only the ARR was still significant (r = 0.108, P = 0.05). In a logistic regression analysis, the ARR predicted MetS index (odds ratio (OR) = 1.07 [95% confidence interval (CI) = 1.011-1.131], P= 0.02) even after adjusting for age, BMI, and gender. On the other hand, aldosterone showed no association with MetS or inflammatory markers.

CONCLUSION

These results suggest a continuum of cardiometabolic risk beyond the classic PA threshold screening. The ARR could be a more sensitive marker of obesity, MetS, and endothelial damage in non-PA patients than aldosterone or renin alone. Prospective studies are needed to develop future screening cutoff values.

Are higher doses of proton pump inhibitors better in acute peptic bleeding?

Although there is broad consensus about the benefits of proton pump inhibitors in acute upper peptic bleeding, there is still controversy over their optimal dosing. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified six systematic reviews including 27 randomized trials addressing this question. We combined the evidence using meta-analysis and generated a summary of findings table following the GRADE approach. We concluded high-dose proton pump inhibitors probably result in little or no difference in re-bleeding rate or mortality. The risk/benefit and cost/benefit balance probably favor use of low-doses.

Nutritional assessment as predictor of complications after hematopoietic stem cell transplantation

Introduction

Nutritional support is pivotal in patients submitted to hematopoietic stem cell transplantation. Nutritional status has been associated with time of engraftment and infection rates. In order to evaluate the association between nutritional parameters and clinical outcomes after transplantation a cohort of transplant patients was retrospectively evaluated.

Methods

All 50 patients transplanted between 2011 and 2014 were included. The nutritional status before transplantation, ten days after transplantation and before discharge was assessed including anthropometry, body mass index, albumin, prealbumin and total urinary nitrogen.

Results

The median follow-up time was 41 months and the median age of patients was 41 years. Thirty-two underwent allogeneic and 18 autologous transplants. Diagnoses included acute leukemias (n = 27), lymphoma (n = 7), multiple myeloma (n = 13), and aplastic anemia (n = 3). Thirty-seven patients developed mucositis (three Grade 1, 15 Grade 2, 18 Grade 3 and one Grade 4), and twenty-two allogeneic, and five autologous transplant patients required total parenteral nutrition. Albumin and total urinary nitrogen were associated with length of hospital stay and platelet and neutrophil engraftment. None of the nutritional parameters evaluated were associated with overall survival. Non-relapse mortality was 14% and overall survival was 79% at 41 months of follow-up.

Conclusions

After hematopoietic stem cell transplantation, high catabolism was associated with longer length of hospital stay, the need of total parenteral nutrition and platelet and neutrophil engraftment times. Nutritional parameters were not associated with overall survival.

15 THERMORESISTANCE SPERM TEST FOR EPIDIDYMAL STALLION SPERM FROZEN WITH TWO CRYOPROTECTANTS

The Peruvian Paso Horse has become a flagship product of Peru, for which it is very important to work on promoting and preserving their genetic material through semen. The objective of this study was to evaluate the thermoresistance of epididymal sperm of stallion frozen with 2 cryoprotectants (dimethylformamide and glycerol). The testes with the epididymides (n = 16) of 8 adult stallions in good health condition were obtained in the slaughter house and transport at isothermal conditions (30°C). Spermatozoa from the epididymis were recovered and incubated with lactated ringer's solution (Hartman solution) for 30 min, centrifuged at 2000 RPM for 15 min, and resuspended with an extender based on sucrose (7%) and egg yolk (3%) with different levels of cryoprotectants: dimethylformamide-DMF (T4%), glycerol-GLI (4%), and a combination of dimethylformamide-DMF (2%) + glycerol-GLI (2%) with an equilibrium time of 20 min at 5°C. The final dilution was 160 million motile spermatozoa placed on 0.5-mL straws. These straws were kept over liquid nitrogen fumes for 15 min over a tripod stand. After cryopreservation, the straws were stored in liquid nitrogen tanks (–196°C). The thawing process of the straws was initiated at 75°C for 7 s, immediately followed by an evaluation of sperm motility at 4 times 0, 30, 60, and 90 min in which sperm was incubated on water bath at 37°C (thermoresistance test). The data was evaluated (ANOVA) with the SAS 9.12 program (SAS Institute Inc., Cary, NC, USA) and, for the media, Tukey's test was carried out. The results showed an effect of the treatment on the motility of the frozen-thawed semen; dimethylformamide, the cryoprotectant, had the best performance. Table 1.Motility of frozen-thawed stallion epididymal sperm (thermoresistance sperm test)1

Evaluation by SPECT-CT of an incidental finding of a thymoma and breast cancer in a myocardial perfusion SPECT with 99mTc-MIBI

We present a case of a 78-year-old female with effort angina. A myocardial perfusion SPECT (MPS) showed increased tracer uptake in two synchronic tumor lesions, a thymoma and a breast cancer. This case highlights the contribution of SPECT-CT in the characterization of these findings and its essential role in rapid decision-making. The patient underwent surgery of both lesions that had gone undetected prior to the conduction of the MPS.

SPECT-CT in the localization of an ectopic retropharyngeal parathyroid adenoma as a cause for persistent primary hyperparathyroidism

A common cause for surgical failure of primary hyperparathyroidism (pHPT) is the non-detection of an ectopic adenoma during the intervention. We present a case of a patient with pHPT in whom an ectopic gland was found in the right retropharyngeal space by means of a double phase (99m)Tc-methoxy-isobutyl-isonitrile ((99m)Tc-MIBI) scintigraphy and early SPECT-CT after several surgeries and imaging tests. The addition of a tomography to the planar scintigraphy increases its sensitivity and improves pathological parathyroid glands localization. The hybrid imaging is sometimes essential to obtain surgical success, as in the case of ectopic adenomas.

Inflammatory cells and ferruginous bodies in bronchoalveolar lavage in urban dogs

OBJECTIVE

To investigate whether high levels of atmospheric pollution modify the inflammatory cell count of the canine lung and to detect the presence of ferruginous bodies (FB) in the respiratory system.

STUDY DESIGN

Bronchoalveolar lavage (BAL) was performed on dogs from four different areas of Mexico City and a rural area. With the BAL fluid recovered, total and differential cell counts were made, and ferruginous bodies were isolated by sodium hypochlorite digestion. They were counted by light microscopy and evaluated as a marker of exposure to particulate pollutants.

RESULTS

There was no significant difference in the total cell count or in the macrophage number between the five groups. The neutrophil count was statistically higher in dogs from the southwest area as compared to the northeast and rural areas (P < .05). The lymphocyte count was significantly greater in the southwest, also. The northeast part of the city showed the highest number of FB in BAL fluids.

CONCLUSION

The most polluted areas, in terms of particulate matter, were the northeast and the northwest; those are the locations of heavy industry. In contrast, in the southwest, where more inflammation was seen, the highest levels of ozone were registered during the year.

Thoracoabdominal wall repair with glutaraldehyde-preserved bovine pericardium

Glutaraldehyde-preserved bovine pericardium (GPBP) is evaluated as a bioprosthesis for the reconstruction of surgical defects in the thoracoabdominal wall. The mechanical properties of bovine pericardium preserved at different concentrations of glutaraldehyde were studied. Samples preserved in 0.5% glutaraldehyde showed a significantly higher tensile strength (11.7 +/- 0.8 N/mm2) than samples preserved in 2.5, 5, or 10% (similar to pericardium preserved in normal saline). The percentage of elongation was significantly lower than samples preserved in 1, 2.5, and 5% glutaraldehyde. GPBP at 0.5% was used to repair experimentally induced defects of the abdominal wall (n = 9), chest wall (n = 6), diaphragm (n = 6), and sternum (n = 7). All animals presented adequate tolerance to the material used and no case of infection or rejection of the material was seen in any of the animals. Finally, 0.5% GPBP was used clinically in a series of 40 patients: postincisional abdominal hernia (n = 30), inguinal hernia (n = 8), diaphragmatic hernia (n = 1), and congenital pelvic defect with prolapse of abdominal organs (n = 1). Surgical use showed that GPBP was a very manageable material and long-term results were good in 37 patients with a mean follow up of 18 months (range 5-35 months). Six patients presented seroma formation (all abdominal hernia patients), three of which eventually developed infection and had the GPBP patch removed at 3, 5, and 7 months postoperatively. The rest of the patients presented good scar formation with adequate resistance at the area of implantation. GPBP is a biological material with sufficient resistance to be used surgically in the repair of thoracoabdominal defects. Ideal concentration of glutaraldehyde to be used in the preparation-preservation of the material is 0.5% since higher concentration negatively affect its tensile rupture strength and elongation.

[Repair of thoracoabdominal wall defects in dogs using a bovine pericardium bioprosthesis]

OBJECTIVES

To evaluate the in-vitro resistance of a pericardial tissue bioprothesis as well as its use for the reconstruction of surgical defects in the thoracoabdominal wall.

MATERIALS AND METHODS

The prosthesis were preserved for 15 days in different concentrations of glutaraldehyde (0.5% to 10%). Normal saline and Hanks solution were used as controls. Tensile strength and percent elongation were measured using an Instrom 1011 automatic equipment; polypropilene (Marlex) and polyester (Mersilene) mesh samples were included. Also, the 0.5% glutaraldehyde-preserved pericardium was used to repair defects experimentally produced in the abdominal wall (n = 12), chest wall (n = 6), diaphragm (n = 6), and sternum (n = 7) of mongrel dogs.

RESULTS

The samples preserved in 0.5% glutaraldehyde showed a significantly higher tensile strength (11.7 N/mm2, SEM = 0.8) than samples preserved in other concentrations as well as in the mesh samples. Percent elongation in 0.5% glutaraldehyde was 56% (SEM = 5.8) which was similar to the meshes' elongation but significantly lower than that seen for the 1%, 2.5% and 5% glutaraldehyde-preserved samples. The dogs showed good tolerance to the 0.5% preparation and the histopathology showed formation of a fibroblast layer with collagen deposits and development of scar tissue. There was no case of infection or rejection in the animals, and all the microbiological cultures of the preparations were negative.

CONCLUSION

Pericardial bioprothesis is a resistant material which can be used surgically in the repair of thoracoabdominal defects.

Pulmonary arterial contribution to airway blood flow after lung transplantation in dogs

Despite the improved success of lung transplantation, ischemia of the donor bronchus continues to be the most important factor influencing airway healing. Recent studies have shown that at the level of the mainstem bronchi the pulmonary contribution to the airway blood flow may be equivalent to or greater than the systemic contribution and could therefore assist early healing of the newly anastomosed bronchus and, in addition, might facilitate the improved healing associated with omentopexy. The aim of this study was to measure the pulmonary contribution to airway blood flow in dogs after allotransplantation of the left lung and to determine whether omentopexy might improve the healing process. Using the radioactive microsphere technique, we measured the pulmonary contribution to airway blood flow in 25 dogs 1 week after allotransplantation of the left lung. Half the dogs had an omental wrap around the anastomotic site. Results showed that pulmonary blood flow increased progressively from lower trachea to distal mainstem bronchus and supplied the left mainstem bronchus above as well as below the anastomotic site. Omentopexy did not increase flow or enhance healing.

Pulmonary perfusion during lung transplant rejection and experimental pneumonia

Six left lung allotransplants were performed in healthy mongrel dogs. Immunosuppression was established with cyclosporine (15 mg/kg/day p.o.) from the day of transplantation for 30 days. Another group of animals (n = 3) was used to produce acute experimental pneumonia by instilling 4-6 ml of a 10(8) CFU suspension of Pseudomonas aeruginosa into the right lower lobe. Dynamic perfusory lung scintigraphy (DPLS) was performed before transplant/pneumonia (control), during acute rejection/pneumonia as detected radiologically, and after treatment with methylprednisolone (1 g/day for 3 days i.v.) (transplant group) or antibiotics (pneumonia group). Seroalbumin macroaggregates (5-8 McI) marked with 99-mTc were injected into the cephalic vein and the percentage of perfusion to each lung was determined. Eight acute rejection episodes were detected. DPLS showed similar perfusion to each lung, whereas during acute rejection perfusion was significantly reduced by almost 30%. Perfusion was reestablished to control levels after treatment with methylprednisolone. Reduction in perfusion correlated with radiological rejection grading. No reduction in left lung perfusion was detected in pneumonia animals. In conclusion, acute rejection reduces perfusion to the transplanted lung as measured by DPLS. Treatment restores normal perfusion.