Hipervolemia mais tríplice oclusão vascular no tratamento da lesão traumática da veia cava retro-hepática e veias hepáticas

BACKGROUND: Liver vascular isolation is essential for the treatment of the retrohepatic vena cava and hepatic veins. Triple vessel occlusion (TVO - occlusion of the portal triad, the inferior vena cava above the renal veins and within the pericardium) is the easiest isolation method for the surgeon. Unfortunately, this technique cannot be applied to hypovolemic and/or shock (cardiac arrest) patients as it compromises venous return. OBJECTIVES: Our objective is to demonstrate that in the above mentioned patients, establishing a previous hypervolemic state allows the safe use of TVO. METHODS: The method includes efficient injury tamponade with aggressive fluid replacement until normal blood volume is reached (resuscitation). Normal blood volume is recognized by a return of arterial blood pressure to normal levels, inferior vena cava filling and an increase in aortic wall tension. Following this procedure, hypervolemia is obtained by the rapid additional infusion of 1.500 to 2.000 ml of fluids. TVO in this situation does not alter the heart rhythm and maintains a clear operative field which is essential for hepatotomy, venorrhaphy and or venous ligation. RESULTS: Three patients were successfully operated.

Cirurgia para controle do dano: uma revisão

Damage control surgery is one of the major advances in surgical practice in the last 20 years. The indications for damage control surgery are: the need to terminate a laparotomy rapidly in an exsanguinating, hypothermic patient who had developed a coagulopathy and who is about to die on the operating table; inability to control bleeding by direct hemostasis; and inability to close the abdomen without tension because of massive visceral edema and a tense abdominal wall. Damage control surgery has three phases: 1) laparotomy to control hemorrhage by packing, shunting, or balloon tamponade, or both; control of intestinal spillage by resection or ligation of damaged bowel, or both; 2) physiological resuscitation to correct hypothermia, metabolic acidosis, and coagulopathy. 3) planned reoperation for definitive repair. Damage control surgery is appropriate in a small number of critically ill patients who are likely to require substantial hospital resources. However, there are many questions that need to be answered. Who is the patient elected for this surgery? When is the ideal time to make the decision? Which are the parameters that indicate to the surgeons the moment to re-operate the patient? How to treat the long-term complications? In the present review we described some historical aspects, indications, technical aspects, advantages and disadvantages of this procedure, as well as its physiological consequences and morbidity and mortality rates of damage control surgery. Damage control surgery offers a simple effective alternative to the traditional surgical management of complex or multiple injuries in critically injured patients.

Inguinal hernias in patients of 50 years and above. Pattern and outcome

OBJECTIVE: to evaluate a one year experience with inguinal hernia repair, in patients of > 50years, with respect to the type of inguinal hernia, type of surgery, postoperative complications and recurrence. METHODS: a prospective descriptive study of patients (n=57) > 50 years operated for inguinal hernia during a one year period. Tension-free meshplasty and herniorrhaphy, using 3"x6" polypropylene mesh and 2-0 polypropylene suture, were performed in elective and emergency surgery respectively. Follow-up visits were scheduled at six weeks, three and six months postoperatively. RESULTS: the most representative age group was 61-70 years, and all patients were male. 52 (91.22%) patients had unilateral inguinal hernias, while five (8.77%) had bilateral hernias. In 50 (87.71%) patients, the hernia was uncomplicated, while seven (12.28%) patients presented with some complication such as obstruction or strangulation. Elective surgery was performed in 50 (87.71%) patients while seven (12.28%) patients were operated in emergency. Postoperatively, 50 (87.7%) patients had uneventful recovery, while seven (12.28%) patients developed some complications which were treated conservatively. Mean hospital stay was six days. One recurrence was observed and there was no peri/postoperative death. CONCLUSION: tension-free meshplasty and herniorrhaphy are safe, simple and applicable even in elderly patients after adequate pre-operative assessment and optimization. Although associated with longer hospital stay, the mortality rate is nil and complication as well as recurrence rate is low. Hence, timely repair is necessary in elderly patients even in those with comorbid conditions.

Use of surgical mesh of different compositions in the correction of the abdominal wall defect in rats

Objective: To analyze the performance of two surgical meshes of different compositions during the defect healing process of the abdominal wall of rats. Methods: thirty-three adult Wistar rats were anesthetized and subjected to removal of an area of 1.5 cm x 2 cm of the anterior abdominal wall, except for the skin; 17 animals had the defect corrected by edge-to-edge surgical suture of a mesh made of polypropylene + poliglecaprone (Group U - UltraproTM); 16 animals had the defect corrected with a surgical mesh made of polypropylene + polidioxanone + cellulose (Group P - ProceedTM). Each group was divided into two subgroups, according to the euthanasia moment (seven days or 28 days after the operation). Parameters analyzed were macroscopic (adherence), microscopic (quantification of mature and immature collagen) and tensiometric (maximum tension and maximum rupture strength). Results : there was an increase in collagen type I in the ProceedTM group from seven to 28 days, p = 0.047. Also, there was an increase in the rupture tension on both groups when comparing the two periods. There was a lower rupture tension and tissue deformity with ProceedTM mesh in seven days, becoming equal at day 28. Conclusion : the meshes retain similarities in the final result and more studies with larger numbers of animals must be carried for better assessment.

Sling de aponeurose e com faixa sintética sem tensão para o tratamento cirúrgico da incontinência urinária de esforço feminina

OBJETIVO: comparar as cirurgias de sling de aponeurose e TVT (do inglês tension-free vaginal tape) para correção da incontinência urinária de esforço (IUE) quanto às taxas de cura subjetiva e objetiva, à mobilidade do colo vesical ao ultra-som, à variação do teste do absorvente, às alterações urodinâmicas e à incidência de complicações. MÉTODOS: foram selecionadas 80 pacientes com IUE. Destas, 61 foram operadas pela técnica de TVT e 19 por sling de aponeurose do reto abdominal. As médias de idade, índice de massa corpórea e paridade foram 50,1 anos, 29,7 kg/m² e 4,5 partos (mediana=3) para as pacientes com sling de aponeurose e de 51,7 anos, 28,1 kg/m² e 4,1 partos (mediana=3) para aquelas com TVT. Todas se submeteram a anamnese, exame físico, ultra-sonografia do colo vesical, teste do absorvente e estudo urodinâmico no pré-operatório e após, pelo menos, seis meses depois da cirurgia. Após 15 ou 19 meses e depois de cerca de quatro a cinco anos, foram novamente entrevistadas quanto aos resultados da cirurgia. RESULTADOS: quanto à avaliação subjetiva, após seis meses, julgaram-se curadas 96,7% das mulheres com TVT e 89,5% das com sling. Porém, após 15 a 19 meses, o Grupo TVT manteve a mesma taxa de cura subjetiva, enquanto que no Grupo Sling houve redução para 77,8%. Houve diminuição significativa da mobilidade do colo vesical, similar em ambos os grupos, e melhora no teste do absorvente. No final do estudo urodinâmico, foram classificadas como cura objetiva 93,4% das mulheres do Grupo TVT e 78,9% daquelas do Grupo Sling. O tempo médio de sondagem vesical foi maior no Grupo Sling. Observou-se retenção urinária em 42,1% dos casos de sling e em 9,8% de TVT. As taxas de cura tardia foram 90% para TVT e 55,6% para sling. CONCLUSÕES: a cirurgia de TVT propiciou melhor taxa de cura subjetiva após 15 ou 19 meses, porém, a taxa de cura objetiva foi igual em ambas as técnicas neste tempo. Entre as complicações detectadas, a retenção urinária no pós-operatório foi superior no Grupo Sling.

Outbreaks of canid herpesvirus 1 disease in puppies in southern Brazil

Abstract: Canid herpesvirus 1 (CHV-1) is a widespread pathogen of dogs and produces infertility, abortions and severe systemic disease in young puppies. Clinical data indicate the circulation of CHV-1 among Brazilian dogs yet definitive diagnosis has rarely been accomplished. This article describes the clinicopathological findings of four independent cases/outbreaks of neonatal disease by CHV-1 in Bulldog puppies followed by virus identification and genetic characterization. Three events occurred in a kennel holding dogs of different breeds at reproductive age (March 2013, October 2013 and April 2014). Puppies from three French or English Bulldog litters, aging 9 to 30 days were affected, presenting dyspnea, agonic breathing, pale mucous, abdominal pain and tension, evolving to death within about 24 hours. At necropsy, the puppies presented necrohemorrhagic hepatitis, multifocal and moderate necrohemorrhagic nephritis and fibrinonecrotic interstitial pneumonia. Virus isolation was positive in clinical specimens from one litter and CHV-1 DNA was detected by PCR in tissues from all four cases. Virus-neutralizing assays with samples of the affected kennel revealed 9/12 adult animals with high antibody titers to CHV-1. Nucleotide sequencing of glycoprotein B, C and D genes revealed 99-100% of identity among the viruses and with CHV-1 sequences available in GenBank. Phylogenetic analyses of gC sequences showed a segregation of the samples, even among three isolates from the same kennel. These findings support CHV-1 infection as the cause of disease and death in these dog litters, reinforcing the need for correct etiologic diagnosis, prevention and immunization against CHV-1 in dogs from Southern Brazil.

Local Web Buckling in Tapered Composite Beams: A Parametric Study

Composite flooring systems supported by tapered (varying web depth) beams are very attractive from an economic point of view. However, the tapered beam sections are fabricated from plate by welding, and are susceptible to imperfection effects. These may interact with the localised compressive stress field that is generated in the web at a slope change in the lower flange to cause local web buckling. A substantial parametric study using a non-linear elasto-plastic finite element program and covering practical ranges of the important parameters including the area of the tension flange, taper slope and web thickness is reported. Moment-rotation relations, peak moments and failure mechanisms have been predicted. The validity of the work is supported by the good correlation obtained between the results of the parametric study and experimental data.

Characterization of nerve-induced relaxation of gastrointestinal sphincteric smooth muscle in a South American opossum (Didelphis albiventris)

The presence of inhibitory nonadrenergic noncholinergic (NANC) intrinsic innervation of the circular muscle of the gastrointestinal sphincters of the South American (SA) opossum was investigated in vitro. Isolated circular muscle strips from the esophagogastric and ileocolonic junctions but not from the gastroduodenal (pylorus) region developed spontaneous tension. Tetrodotoxin (TTX, 1 µM) augmented the spontaneous tension only in the ileocolonic junction strips. Electrical field stimulation of esophagogastric and ileocolonic junction strips caused frequency-dependent responses consisting of a relaxation at lower frequencies (<1 Hz) and a biphasic response or contraction at higher frequencies. In the strips from the pyloric region electrical field stimulation abolished the spontaneous activity at lower frequencies and induced contractions at higher frequencies. The responses elicited by electrical field stimulation in the three sphincters were abolished by TTX (1 µM). Electrical field-induced contractions were reduced while relaxations were enhanced by atropine (1 µM). In the presence of atropine (1 µM) and guanethidine (3 µM), electrical field stimulation, nicotine and ATP induced frequency- or concentration-dependent relaxations of the three sphincters that were abolished by TTX (1 µM). Isoproterenol and sodium nitroprusside caused concentration-dependent relaxations which were TTX-resistant. These findings indicate that the sphincteric circular muscle of the SA opossum gastrointestinal tract is relaxed by the activation of intrinsic NANC nerves and therefore can be used as a model for the study of the mechanisms involved in these responses

The rate of force generation by the myocardium is not influenced by afterload

The influence of afterload on the rate of force generation by the myocardium was investigated using two types of preparations: the in situ dog heart (dP/dt) and isolated papillary muscle of rats (dT/dt). Thirteen anesthetized, mechanically ventilated and thoracotomized dogs were submitted to pharmacological autonomic blockade (3.0 mg/kg oxprenolol plus 0.5 mg/kg atropine). A reservoir connected to the left atrium permitted the control of left ventricular end-diastolic pressure (LVEDP). A mechanical constriction of the descending thoracic aorta allowed to increase the systolic pressure in two steps of 20 mmHg (conditions H1 and H2) above control values (condition C). After arterial pressure elevations (systolic pressure C: 119 ± 8.1; H1: 142 ± 7.9; H2 166 ± 7.7 mmHg; P<0.01), there were no significant differences in heart rate (C: 125 ± 13.9; H1: 125 ± 13.5; H2: 123 ± 14.1 bpm; P>0.05) or LVEDP (C: 6.2 ± 2.48; H1: 6.3 ± 2.43; H2: 6.1 ± 2.51 mmHg; P>0.05). The values of dP/dt did not change after each elevation of arterial pressure (C: 3,068 ± 1,057; H1: 3,112 ± 996; H2: 3,086 ± 980 mmHg/s; P>0.05). In isolated rat papillary muscle, an afterload corresponding to 50% and 75% of the maximal developed tension did not alter the values of the maximum rate of tension development (100%: 78 ± 13; 75%: 80 ± 13; 50%: 79 ± 11 g mm-2 s-1, P>0.05). The results show that the rise in afterload per se does not cause changes in dP/dt or dT/dt

Paraquat poisoning: an experimental model of dose-dependent acute lung injury due to surfactant dysfunction

Since the most characteristic feature of paraquat poisoning is lung damage, a prospective controlled study was performed on excised rat lungs in order to estimate the intensity of lesion after different doses. Twenty-five male, 2-3-month-old non-SPF Wistar rats, divided into 5 groups, received paraquat dichloride in a single intraperitoneal injection (0, 1, 5, 25, or 50 mg/kg body weight) 24 h before the experiment. Static pressure-volume (PV) curves were performed in air- and saline-filled lungs; an estimator of surface tension and tissue works was computed by integrating the area of both curves and reported as work/ml of volume displacement. Paraquat induced a dose-dependent increase of inspiratory surface tension work that reached a significant two-fold order of magnitude for 25 and 50 mg/kg body weight (P<0.05, ANOVA), sparing lung tissue. This kind of lesion was probably due to functional abnormalities of the surfactant system, as was shown by the increase in the hysteresis of the paraquat groups at the highest doses. Hence, paraquat poisoning provides a suitable model of acute lung injury with alveolar instability that can be easily used in experimental protocols of mechanical ventilation

E. coli a-hemolysin: a membrane-active protein toxin

Alpha-Hemolysin is synthesized as a 1024-amino acid polypeptide, then intracellularly activated by specific fatty acylation. A second activation step takes place in the extracellular medium through binding of Ca2+ ions. Even in the absence of fatty acids and Ca2+ HlyA is an amphipathic protein, with a tendency to self-aggregation. However, Ca2+-binding appears to expose hydrophobic patches on the protein surface, facilitating both self-aggregation and irreversible insertion into membranes. The protein may somehow bind membranes in the absence of divalent cations, but only when Ca2+ (or Sr2+, or Ba2+) is bound to the toxin in aqueous suspensions, i.e., prior to its interaction with bilayers, can a-hemolysin bind irreversibly model or cell membranes in such a way that the integrity of the membrane barrier is lost, and cell or vesicle leakage ensues. Leakage is not due to the formation of proteinaceous pores, but rather to the transient disruption of the bilayer, due to the protein insertion into the outer membrane monolayer, and subsequent perturbations in the bilayer lateral tension. Protein or glycoprotein receptors for a-hemolysin may exist on the cell surface, but the toxin is also active on pure lipid bilayers.

Endothelium-dependent vasodilation in response to Pseudomonas aeruginosa lipopolysaccharide: an in vitro study on canine arteries

Early systemic arterial hypotension is a common clinical feature of Pseudomonas septicemia. To determine if Pseudomonas aeruginosa endotoxin induces the release of endothelium-derived nitric oxide (EDNO), an endogenous nitrovasodilator, segments of canine femoral, renal, hepatic, superior mesenteric, and left circumflex coronary arteries were suspended in organ chambers (physiological salt solution, 95% O2/5% CO2, pH 7.4, 37oC) to measure isometric force. In arterial segments contracted with 2 µM prostaglandin F2a, Pseudomonas endotoxin (lipopolysaccharide (LPS) serotype 10(Habs) from Pseudomonas aeruginosa (0.05 to 0.50 mg/ml)) induced concentration-dependent relaxation of segments with endothelium (P<0.05) but no significant change in tension of arteries without endothelium. Endothelium-dependent relaxation in response to Pseudomonas LPS occurred in the presence of 1 µM indomethacin, but could be blocked in the coronary artery with 10 µM NG-monomethyl-L-arginine (L-NMMA), a competitive inhibitor of nitric oxide synthesis from L-arginine. The inhibitory effect of L-NMMA on LPS-mediated vasorelaxation of the coronary artery could be reversed by exogenous 100 µM L-arginine but not by 100 µM D-arginine. These experiments indicate that Pseudomonas endotoxin induces synthesis of nitric oxide from L-arginine by the vascular endothelium. LPS-mediated production of EDNO by the endothelium, possibly through the action of constitutive nitric oxide synthase (NOSc), may decrease systemic vascular resistance and may be the mechanism of early hypotension characteristic of Pseudomonas septicemia.

Collagen arrangement in hepatic granuloma in mice infected with Schistosoma mansoni: dependence on fiber radiation centers

The collagen structure of isolated and in situ liver granuloma from Swiss Webster mice infected with Schistosoma mansoni was sequentially and three-dimensionally analyzed during different times of infection (early acute, acute, transitional acute-chronic, and chronic phases) by laser scanning confocal microscopy and electron scanning variable vacuum microscopy. The initial granuloma structure is characterized by vascular collagen residues and by anchorage points (or fiber radiation centers), from where collagenous fibers are angularly shed and self-assembled. During the exudative-productive stage, the self-assembly of these fibers minimizes energy and mass through continuous tension and focal compression. The curvature or angles between collagen fibers probably depends on the fibroblastic or myofibroblastic organization of stress fibers. Gradually, the loose unstable lattice of the exudative-productive stage transforms into a highly packed and stable architecture as a result of progressive compactness. The three-dimensional architecture of granulomas provides increased tissue integrity, efficient distribution of soluble compounds and a haptotactic background to the cells.

Anti-hyperalgesic effect of electroacupuncture in a model of post-incisional pain in rats

Electroacupuncture has been proposed to be a low cost and practical method that allows effective pain management with minimal collateral effects. In this study we have examined the effect of electroacupuncture against the hyperalgesia developed in a model of post-incisional pain in rats. A 1-cm longitudinal incision was made through the skin and fascia of the plantar region of the animal hind paw. Mechanical hyperalgesia in the incision was evaluated 135 min after the surgery with von Frey filaments. The tension threshold was reduced from 75 g (upper limit of the test) to 1.36 ± 0.36 g (mean ± SEM) in control rats. It is shown that a 15-min period of electroacupuncture applied 120 min after surgery to the Zusanli (ST36) and Sanyinjiao (SP6) points, but not to non-acupoints, produces a significant and long-lasting reduction of the mechanical hyperalgesia induced by the surgical incision of the plantar surface of the ipsilateral hind paw. The tension threshold was reduced from 75 to 27.6 ± 4.2 g in animals soon after the end of electroacupuncture. The mechanical threshold in this group was about 64% less than in control. Electroacupuncture was ineffective in rats treated 10 min earlier with naloxone (1 mg/kg, ip), thus confirming the involvement of opioid mechanisms in the antinociceptive effects of such procedure. The results indicate that post-incisional pain is a useful model for studying the anti-hyperalgesic properties of electroacupuncture in laboratory animals.

Antagonism by hemoglobin of effects induced by L-arginine in neuromuscular preparations from rats

Nitric oxide (NO)-synthase is present in diaphragm, phrenic nerve and vascular smooth muscle. It has been shown that the NO precursor L-arginine (L-Arg) at the presynaptic level increases the amplitude of muscular contraction (AMC) and induces tetanic fade when the muscle is indirectly stimulated at low and high frequencies, respectively. However, the precursor in muscle reduces AMC and maximal tetanic fade when the preparations are stimulated directly. In the present study the importance of NO synthesized in different tissues for the L-Arg-induced neuromuscular effects was investigated. Hemoglobin (50 nM) did not produce any neuromuscular effect, but antagonized the increase in AMC and tetanic fade induced by L-Arg (9.4 mM) in rat phrenic nerve-diaphragm preparations. D-Arg (9.4 mM) did not produce any effect when preparations were stimulated indirectly at low or high frequency. Hemoglobin did not inhibit the decrease of AMC or the reduction in maximal tetanic tension induced by L-Arg in preparations previously paralyzed with d-tubocurarine and directly stimulated. Since only the presynaptic effects induced by L-Arg were antagonized by hemoglobin, the present results suggest that NO synthesized in muscle acts on nerve and skeletal muscle. Nevertheless, NO produced in nerve and vascular smooth muscle does not seem to act on skeletal muscle.