Bilateral recurrent nerve paralysis associated with multinodular substernal goiter: a case report

Substernal goiter is an infrequent occurrence and is found in two to five per cent of all patients undergoing thyroid surgery. These lesions are well known to cause respiratory symptoms and alterations in phonation due to direct compression of airway structures. Infrequently, unilateral recurrent nerve palsy has been reported in patients with substernal goiter. We report a case of bilateral recurrent nerve palsy associated with multinodular substernal goiter in an 89-year-old female who presented in respiratory distress.     

Self-expanding endovascular stent-graft implant for treatment of descending aortic diseases

A bstract Background: Aneurysms and dissections involving the descending thoracic aorta and the distal portion of the aortic arch are difficult to resolve surgically. The introduction of endovascular self-expanding stent-grafts has simplified the operation. Given the complications associated with their peripheral placement, we explored the feasibility of surgical insertion. Methods: Thirteen patients underwent surgical insertion of a stent-graft into the aortic arch via longitudinal aortotomy. Six patients had aneurysms (ruptured in two, and seven dissections (acute in two, ruptured in one). Five patients also underwent associated procedures including aortic valve replacement (one), ascending aorta replacement (two), arch replacement (one), and coronary artery bypass (one). Results: There was one intraoperative death due to ascending aortic dissection, and two hospital deaths due to multiple complications. Of ten patients discharged, one died 3 months postoperatively. The remaining survivors are well, and imaging studies confirmed adequate correction of the aortic disease. Conclusions: The use of this technique simplifies the operation and treatment of particular cases of aortic disease. The observed morbidity and mortality are due to factors independent of the technique.     

Ascaris–Trichuris association and malnutrition in Brazilian children

This work was designed to evaluate the role of intestinal parasites on nutritional status in three rural areas of Brazil. A total of 520 children aged 1–12 years were studied through a questionnaire concerning housing, socio-economic conditions and a 24-h food intake recall. Measurements of weight and height were also performed, and three stool samples were collected on consecutive days for parasitological analysis. Scores of the standard deviation (z-scores) for the weight-for-height and height-for-age were used to characterise the growth profile. A high prevalence of intestinal parasites was detected, with Giardia lamblia (44%), Endolimax nana (43%), Ascaris lumbricoides (41%) and Trichuris trichiura (40%) being the most prevalent. Eleven per cent of the children were classified as showing stunting. Inadequate daily caloric intake was observed in 78% of the population and the proportion of those with inadequate protein intake was 34%. Logistic regression analysis was employed for the multivariate study. Stunting was significantly associated with estimators of low economic income, inadequate protein intake and polyparasitism, especially the association between Ascaris lumbricoides and Trichuris trichiura .     

A comparative study in rats of the in vitro and in vivo pharmacology of the acetylcholinesterase inhibitors tacrine, donepezil and NXX-066

The in vitro and in vivo effects of the novel acetylcholinesterase inhibitors donepezil and NXX-066 have been compared to tacrine. Using purified acetylcholinesterase from electric eel both tacrine and donepezil were shown to be reversible mixed type inhibitors, binding to a similar site on the enzyme. In contrast, NXX-066 was an irreversible non-competitive inhibitor. All three compounds were potent inhibitors of rat brain acetylcholinesterase (IC50 [nM]; tacrine: 125 +/- 23; NXX-066: 148 +/- 15; donepezil: 33 +/- 12). Tacrine was also a potent butyrylcholinesterase inhibitor. Donepezil and tacrine displaced [3H]pirenzepine binding in rat brain homogenates (IC50 values [microM]; tacrine: 0.7; donepezil: 0.5) but NXX-066 was around 80 times less potent at this M1-muscarinic site. Studies of carbachol stimulated increases in [Ca2+]i in neuroblastoma cells demonstrated that both donepezil and tacrine were M1 antagonists. Ligand binding suggested little activity of likely pharmacological significance with any of the drugs at other neurotransmitter sites. Intraperitoneal administration of the compounds to rats produced dose dependent increases in salivation and tremor (ED50 [micromol/kg]; tacrine: 15, NXX-066: 35, donepezil: 6) with NXX-066 having the most sustained effect on tremor. Following oral administration, NXX-066 had the slowest onset but the greatest duration of action. The relative potency also changed, tacrine having low potency (ED50 [micromol/kg]; tacrine: 200, NXX-066: 30, donepezil: 50). Salivation was severe only in tacrine treated animals. Using in vivo microdialysis in cerebral cortex, both NXX-066 and tacrine were found to produce a marked (at least 30-fold) increase in extracellular acetylcholine which remained elevated for more than 2 h after tacrine and 4 h after NXX-066.     

Myrcene mimics the peripheral analgesic activity of lemongrass tea.

Oral administration of an infusion of lemongrass (Cymbopogon citratus) fresh leaves to rats produced a dose-dependent analgesia for the hyperalgesia induced by subplantar injections of either carrageenin or prostaglandin E2, but did not affect that induced by dibutyryl cyclic AMP. These results indicate a peripheral site of action which was confirmed with the essential oil obtained by steam distillation of the leaves. Silica gel column fractionation of the essential oil allowed the identification of myrcene as the major analgesic component in the oil. Identification of the components was made by thin-layer chromatography and checked by mass spectrometry. The peripheral analgesic effect of myrcene was confirmed by testing a standard commercial preparation on the hyperalgesia induced by prostaglandin in the rat paw test and upon the contortions induced by intraperitoneal injections of iloprost in mice. In contrast to the central analgesic effect of morphine, myrcene did not cause tolerance on repeated injection in rats. This analgesic activity supports the use of lemongrass tea as a "sedative" in folk medicine. Terpenes such as myrcene may constitute a lead for the development of new peripheral analgesics with a profile of action different from that of the aspirin-like drugs.     

The role of gamma interferon in infection of susceptible mice with murine coronavirus,MHV-JHM

Summary Infection of BALB/c mice with mouse hepatitis virus, strain JHM (MHV-JHM), at any of several intervals relative to ovalbumin (OVA) administration resulted in elevated OVA-specific IgG 2 a titers. Since gamma interferon (IFN) has been implicated as an up-regulator of IgG 2 a production, attempts were made to determine whether levels of this cytokine were modified in sera of infected mice. Serum IFN- was not detected, but treatment of MHV-JHM-infected mice with monoclonal anti-IFN- antibody resulted in high mortality with decreased survival times, enhanced virus titers in liver and spleen, and more severe virus-associated pathology, compared to mock-treated, infected mice. Immunotherapy with recombinant IFN- ameliorated disease as reflected by mortality rates and virus titers in target organs.     

Attempts to culturing triatominae in the laboratory using "in vitro" feeding]

In order to simplify breeding of triatominae in the laboratory, for performing xenodiagnosis and other biologic studies, we tried to feed the insects "in vitro" with citrated or defibrinated blood from commercially abated chicken. Two types of efficacy observations were carried out with Triatoma infestans: a) analysis of the chaining of successive nymphal stages, viability of satisfactory matching, fertile oviposition and adequate reproduction; b) assessment of viability and infectivity of Trypanosoma cruzi in the insects. As a conclusion, it became evident that, despite operational easiness, the objectives were not achieved, since the classical procedure used as the control, was always superior.     

Neuropsychiatric evaluation in subjects chronically exposed to organophosphate pesticides.

Long-term exposure to low levels of organophosphate pesticides (OP) may produce neuropsychiatric symptoms. We performed clinical, neuropsychiatric, and laboratory evaluations of 37 workers involved in family agriculture of tobacco from southern Brazil who had been exposed to OP for 3 months, and in 25 of these workers, after 3 months without exposure to OP. Plasma acetylcholinesterase activity levels of all subjects were within the normal range (3.2 to 9.0 U/l) and were not different between on- and off-exposure periods (4.7 +/- 0.9 and 4.5 +/- 1.1 U/l, respectively). Clinically significant extrapyramidal symptoms were present in 12 of 25 subjects, which is unexpected in such a population. There was a significant reduction of extrapyramidal symptoms after 3 months without exposure to OP, but 10 subjects still had significant parkinsonism. Mini-mental and word span scores were within the expected range for this population and were not influenced by exposure to OP. Eighteen of the 37 subjects (48%) had current psychiatric diagnoses in the first interview (13 with generalized anxiety disorder and 8 with major depression). Among the 25 subjects who completed both evaluations, the total number of current psychiatric diagnoses, after 3 months without using OP, dropped from 24 to 13 and the number of affected individuals with any psychiatric diagnosis dropped from 11 to 7. In conclusion, this study reinforces the need for parameters other than acetylcholinesterase activity to monitor for chronic consequences of chronic low-dose OP exposure, and it suggests that subjects have not only transient motor and psychiatric consequences while exposed, but may also develop enduring extrapyramidal symptoms.     

Resolution of isoforms of mutalysin II, the metalloproteinase from bushmaster snake venom

Mutalysin II, a zinc endopeptidase possessing direct-acting fibrinolytic activity has been previously purified from bushmaster (Lachesis muta muta) snake venom. We now report a method to isolate two isoforms of natural mutalysin II (mut IIa and mut IIb) using chromatographies on Sephacryl S-200, CM Sepharose CL 6B and Sephadex G-50. The two proteins are monomeric non-glycosylated proteinases with similar molecular masses of 23 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Tryptic peptide mapping of the two native enzymes suggested a large degree of structural similarity. Both isoforms showed high similarity in all enzymatic properties using fibrinogen, fibrin and dimethylcasein as substrates. Thus, the specific fibrinolytic activity was estimated as 12±1.04 and 11.5±1.02 U/μg for mut IIa and mut IIb, respectively. The antigenic cross-reactivity of both isoforms was examined using rabbit hyperimmune serum or immunoglobulin G anti-mut IIa assays on immunodiffusion microscope slides, indirect enzyme-linked immunoabsorbent assay and western blots. From these experiments it was concluded that the two metalloproteinases mut IIa and mut IIb share identical antigenic structures. Since the stability of mutalysin II is dependent upon the presence of zinc, we examined the EDTA sensitivity of the isoforms of mutalysin II. Thus, the IC₅₀ values (concentration of EDTA to produce 50% inhibition of dimethylcasein hydrolysis) for mut IIa is 180 μM and 165 μM for mut IIb.