Modified model of sub-critical size cranial defect in the rabbit / Modelo modificado de defecto craneal de tamaño subcrítico de conejo

In medical sciences, any experimental animal model should be reproducible and adequate to the purpose of simulated human physiological response. In bone injury response research, when bone substitutes are in use, it is of primary importance that studied defects fail to heal unless treated with the tissue engineering therapy under study. This failure defines the concept of "critical size defect" (CSD) wich has different limits according to the animal species used and the location of the defect. Although this is a basic concept, when the aim of the study is to investigate the interface Bone-Biomaterial, it is of primary importance to obtain as much contact area as possible. In order to do so, we propose a modified surgical approach to the classical bi-parietal round sub-critical defect model in rabbit vault.

En las ciencias médicas, cualquier modelo animal de experimentación debe ser reproducible y ajustado al propósito de simular la respuesta fisiológica humana. En la investigación de la respuesta a la lesión ósea, cuando son utilizados sustitutos óseos, es de gran importancia el estudio de defectos que no logran sanar, a menos que sean tratados con terapia de ingeniería de tejidos. Este fracaso define el concepto de "defecto de tamaño crítico" (CDS) el cual tiene límites diferentes según la especie animal utilizada y la ubicación del defecto. Aunque se trata de un concepto básico, cuando el objetivo del estudio es investigar la interfaz hueso-biomaterial, es de primordial importancia obtener la máxima superficie de contacto que sea posible. Para ello, se propone una modificación en el enfoque quirúrgico del modelo clásico de defecto de tamaño subcrítico biparietal en la bóveda de conejo.

Fenótipo Pena-Shokeir. Caso clínico / Pena-Shokeir phenotype. Case report

O fenótipo Pena-Shokeir (PSP) é caracterizado porartrogripose, hipoplasia pulmonar e anomalias faciais. Foirecentemente sugerido que seria secundário à redução dosmovimentos in utero devido a uma patologia intrínseca,independentemente da causa (Sequência de Deformação daAcinésia Fetal - FADS). Os autores descrevem um casoclássico de PSP com uma primeira ecografia obstétrica às 21semanas de gestação revelando diminuição dos movimentosfetais, micrognatia, mãos cerradas e pés botos. Aamniocentese revelou um cariótipo 46,XY normal. Às 23semanas, a ecografia obstétrica mostrou um feto imóvel,com restrição do crescimento intra-uterino e morfologiasobreponível, a que se associava hidrâmnios. O prognósticofoi explicado aos pais que decidiram interromper a gravidez.O estudo anátomo-patológico post mortem revelouhipertelorismo, orelhas de implantação baixa, micrognatia,pescoço curto e largo, discreto pterigia axilar e inguinal,flexão rígida das articulações dos cotovelos e anca,hiperextensão rígida dos joelhos, camptodactilia, pés botos,diminuição da massa muscular e hipoplasia pulmonar. Comoem muitos outros casos de PSP, a etiologia não foiesclarecida(AU)

Pena-Shokeir Phenotype (PSP) is characterized byarthrogryposis, facial anomalies and pulmonary hypoplasia.It has recently been suggested that it is secondaryto the reduction of movements in the uterus dueto an intrinsic pathology regardless of the cause (FetalAkinesia Deformation Sequence). Authors describe acase of a classic PSP, with a first obstetric ultrasound at 21 weeks of gestational age revealing reduction of fetalmovements, micrognathia, limb abnormalities withclubbed feet and clenched hands. Amniocentesis revealeda normal 46,XY karyotype. At 23 weeks, obstetricultrasound revealed intra-uterine growth restriction withabnormal fetal movements profile, identical fetal morphologyplus hypertelorism and new-onset polyhydramnios.Prognosis was explained to the parents who decidedto terminate pregnancy. Pathological study foundhypertelorism, low-set ears, micrognathia, short largeneck, small axillary and inguinal pterigia, rigid flexionat the elbows and hips with hyperextended knees, camptodactyly,clubbed feet, diminished muscle bulk andpulmonary hypoplasia. As in many other cases of PSP,etiology was not clarified(AU)

Magnetic resonance imaging in the preoperative staging of endometrial carcinoma.

PURPOSE OF INVESTIGATION: Magnetic resonance imaging (MRI) has emerged as an important imaging modality in the evaluation of the extension of endometrial carcinoma which is essential in planning treatment and predicting prognosis. This study aimed to assess the value of MRI in the preoperative staging of endometrial carcinoma. METHODS: We included in this study 162 patients with a histological diagnosis of endometrial carcinoma who underwent MRI pelvic imaging and surgical staging. MRI images were compared with pathological findings to measure MRI's sensitivity, specificity, positive and negative predictive values and diagnostic accuracy in what concerns myometrial, cervical and lymph node invasion. RESULTS: MRI differentiation of deep myometrial invasion from superficial disease agreed with pathological findings in 77% of cases, with a sensitivity of 83%, a specificity of 72% and a diagnostic accuracy of 77%. Concerning cervical invasion, MRI had a sensitivity, specificity and diagnostic accuracy of 42%, 92%, 81% respectively. In assessing lymph node invasion, MRI presented a sensitivity of just 17%, a specificity of 99% and a diagnostic accuracy of 89%. CONCLUSION: Our study confirmed the high accuracy of MRI imaging in assessing myometrial and cervical invasion in endometrial carcinoma. When evaluating lymph node invasion, micrometastases are responsible for the low sensitivy of MRI.

Benign and malignant mammary tumors induced by DMBA in female Wistar rats.

This study pretends to characterize 7, 12-dimetylbenz[a]anthracene-induced benign and malignant tumors. One hundred and twenty female Wistar rats were randomly allocated to two groups: Control Group and Induction Group; IG animals were given a single dose of DMBA and killed 24 weeks after. Other tumors besides breast tumors were diagnosed, mainly tumors of the salivary glands and ovarian benign epithelial tumors. Incidence of breast disorders was about 60%. Macroscopic mammary tumors varied in dimension from 2 mm to 55 mm. Malignant breast tumors (n = 56) were essentially invasive ductal carcinomas (91.1%), G1 (92.2%), presenting histologic characteristics of good prognosis. Predominant benign breast disorders consisted of glandular (68.6%) and atypical (20%) hyperplasias reproducing histologic types of human breast diseases. Different individual susceptibility to DMBA apparently occurs; while some rats never developed neoplasias, others exhibited several tumors.

Influence of 0.1 or 0.2% cholesterol-enriched diets on the induction of atherosclerosis and aorta reactivity in vitro.

Current knowledge of atherogenesis is largely based on animal models of hypercholesterolemia, which rarely show changes similar to the lesions described in humans. We studied the influence of two low cholesterol-enriched diets on the development of anatomopathologic lesions and on the reactivity of the isolated aorta in rabbits. Compared with controls (rabbits fed a normal diet), a 0.1% cholesterol-enriched diet over a 6- or 9-month period produced increases of the 5-hydroxytryptamine (5-HT)-induced contractile responses, as well as a decreases in acetylcholine (ACh)-induced relaxing response (endothelium-dependent, through the production of NO). Noradrenaline (NA)-induced contractions and relaxations elicited by sodium nitroprusside (SNP; endothelium independent) were not significantly modified. Because at 6 months, significant anatomopathologic intimal early lesions were not found, functional endothelial changes can explain such findings. There was a defect in NO synthesis, release, or diffusion; 5 HT, but not NA, may be responsible for inducing NO production. In 0.2% cholesterol-fed rabbits at 4 and 12 weeks, increases of 5-HT- and NA-induced contractile responses were found. In both cases, there was a decrease of ACh-induced relaxing effect, whereas responses to SNP remained unchanged. Intimal early and advanced lesions were present at both the 4- and 12-week periods. These data suggest abnormalities of the NO system. The effects obtained with NA may be explained by a possible decrease of catechol-O-methyltransferase (COMT) or monoamine oxidase (MAO) activities or both or by decreased amine uptake. The extent to which NA may induce NO production is small, because changes in NA-induced contractions are verified only in the presence of significant alterations in the endothelium. The use of a 0.2% cholesterol diet for a short time may induce atherosclerotic lesions, whereas the 0.1% cholesterol diet for a 9-month period, besides being closer to the human diet, allows the detection of functional abnormalities before the evidence of structural lesions.

[Pulse wave velocity as initial marker of atherosclerosis]. / A velocidade da onda de pulso como marcador inicial da doença aterosclerótica.

OBJECTIVE: To evaluate the influence of hypercholesterolaemia on arterial distensibility. MATERIAL AND METHODS: 43 male New Zealand White rabbits, with similar ages and weights, were included in the present study. The animals were divided in two groups: Group A (n = 15) was fed a normal diet; Group B (n = 28) was fed normal diet plus 0.1% cholesterol. at the beginning and after 6 and 9 months, blood samples were obtained for determination of serum cholesterol (total, esterified, LDL) and Triglyceride levels. Pulse wave velocity (PWV) was also evaluated, by mecanography, after 6 and 9 months of the beginning of the experiment. After 6 months (Group A = 4 and Group B = 7) and 9 months (Group A = 6 and Group B = 7) of the experiment, some animals were killed for anatomopathological studies. RESULTS: Major differences were obtained between the two groups, specially in what concerns to LDL and cholesterol levels (p < 0.001). There was also a remarkable difference in PWV between the two groups (6.078 +/- 0.162/9.002 +/- 0.196 m/s at 6 months and 7.639 +/- 0.590/9.557 +/- 0.543 m/s at 9 months) from the rabbits fed normal or cholesterol diet, respectively. The anatomical lesions were only significant after 9 months. However there was a decrease in aorta internal diameters at thoracic and renal levels at 6 months (34% and 53%) and at 9 months (29% and 33%), without significant changes in their thickness. In the heart, the left ventricle (LV) had a significant thickness increase after 6 months (about 43%). CONCLUSIONS: These data indicate that even before anatomical lesions had occurred, important functional changes are present, in the arterial wall. Then, the evaluation of the PWV could be a promising non-invasive diagnostic method of early atherosclerosis, with obvious implications concerning its prophylaxis and therapy.

[Enalapril prevents myocardial remodeling in rats with arteriovenous fistula]. / O enalapril previne a remodelação miocárdica em ratos com fístula arteriovenosa.

AIM OF THE STUDY: To evaluate the efficacy of enalapril in preventing cardiac myocyte remodelling in rats with arteriovenous fistulas. EXPERIMENTAL DESIGN: We distributed thirty males Wistar rats in 3 groups: group A (control), group B (fistula) and group C (fistula + enalapril). An end to side fistula between the femoral artery and vein was produced in the right thighs of rats from groups B and C. Oral enalapril (0.07 mg/kg/day) was given to rats from group C. After 8 weeks the rats were sacrificed and their heart removed for pathologic study. RESULTS: Body weight evolution was similar in all groups. Heart weight increased in group B (1.78 +/- 0.2 g) when compared to group A (1.55 +/- 0.11 g), (p < 0.02), and was similar (p = n.s.) in groups A and C (1.58 +/- 0.13 g). Heart weight/Body weight ratio was also increased in group B (4.4 +/- 0.55 mg/g) when compared to group A (3.6 +/- 0.5 mg/g), (p < 0.01), but was similar in groups A and C (3.66 +/- 0.4 mg/g) (p = n.s.). An increase in wall thickness was detected in group B in the right ventricle (p < 0.03), septum (p < 0.01) and left ventricle (p < 0.01) when compared to groups A and C. Myocytes cytoplasm volume fraction was increased in group B, when compared with group A, in all segments studied (right ventricle p = 0.011, septum p = 0.025, and left ventricle p = 0.031). Groups A and C were similar. CONCLUSION: Enalapril prevents the structural remodelling of cardiac myocytes in this model of volume overload induced by an arteriovenous fistula.

Experimental atherogenesis and vascular noradrenaline content in NZW rabbits and activity of a new nicotinic acid derivative (L 44-0).

New Zealand White rabbits fed a low-level cholesterol-enriched diet (0.1%) were used to study and characterize a possible model of experimental atherogenesis. For the determination of the degree of atherosclerosis, more consistent and reproducible morphometric methods were used. Simultaneously the influence of plasma cholesterol levels on vascular noradrenaline content was studied. The effect of a new lipid-regulating drug (0.1% L 44-0, the N-oxide of a nicotinic acid derivative) on analyzed parameters was studied as well. This study suggests that the low-level cholesterol-enriched diet is atherogenic, with macroscopically detectable lesions of atherosclerosis becoming apparent by week 12 of the study. The same diet increases the vascular noradrenaline content in the renal artery and in the femoral artery and vein; however, it does not influence that content in the carotid and mesenteric arteries. L 44-0 counteracts most of the observed effects.