Medidas comparativas do padrão morfométrico e perfil energético de éguas Crioulas no terço final da gestação, com diferentes escores corporais / Comparative measurements of the morphometric pattern and energy profile of Crioula mares in the final third of gestation, with different body condition scores

O objetivo deste estudo é comparar e descrever medidas morfométricas e perfil energético de éguas da raça Crioula no terço final da gestação. Foram utilizadas vinte éguas gestantes, divididas em 2 grupos conforme o escore corporal (BCS); o GrN (n=10), grupo de éguas com BCS 5 ou moderado, e GrO (n=10), grupo de éguas obesas ou BCS 9, analisadas conforme o mês de gestação (8º, 9º, 10º e 11º). Foram realizadas coletas de sangue e avaliações morfométricas mensais do peso corporal (PC), perímetro torácico (PT), perímetro abdominal (PA), altura da crista do pescoço (AC), espessura de gordura subcutânea na base da cauda (EGBC) e espessura de gordura retroperitoneal (EGRP). Para avaliar o perfil energético, foram mensurados os níveis séricos de triglicerídeos (TAG), ácidos graxos não esterificados (NEFA), Leptina (LEP) e Adiponectina. Os resultados das mensurações analisadas demonstraram no GrN incremento (P<0,05) nas variáveis PC, PT, PA e NEFA do 8º para o 9º mês de gestação. Porém, na variável EGBC, o aumento (P<0,01) foi observado entre o 8º e o 11º mês avaliado. No GrO, o PA demonstrou incremento (P<0,01) entre o 8º e o 11º mês de gestação, e a LEP apresentou aumento (P<0,05) entre o 10º e o 11º mês. Quando os dois grupos foram comparados, as variáveis PC, PT, EGBC e EGRP apresentaram diferença (P<0,05) em todos os meses avaliados. Na análise de correlação, o BCS associou-se com o PC (r=0,691; P<0,0001), PT (r=0,705; P<0,0001), EGBC (r=0,701; P<0,0001), EGRP (r=0,627; P<0,0001), níveis séricos de LEP (r=0,426; P<0,0001) e Adiponectina (r=0,217; P<0,05). Dessa forma, pode-se afirmar que a gordura corporal aumentou progressivamente nas éguas do GrN, diferentemente do observado no GrO. Através dos métodos utilizados neste trabalho, torna-se possível a avaliação prática da morfometria das éguas da raça Crioula no terço final da gestação, possibilitando de forma objetiva a identificação de indivíduos obesos(AU)

The aim of this study was to compare and describe morphometric measurements and energy profile of the Crioula breed mares at the end of gestation. Twenty pregnant mares were used and separated into 2 groups according to body condition score (BCS). The GrN (n= 10) group of mares with BCS 5 or moderate and GrO (n = 10) group of obese mares or BCS 9 were analyzed according to the month of pregnancy (8th, 9th, 10th and 11th). Blood samples and monthly morphometric evaluation were performed for body weight (PC), heart girth (PT), waist circumference (PA), height of the crest of the neck (AC), thickness subcutaneous fat on the base of the tail (EGBC) and retroperitoneal (EGRP). To evaluate the energy profile serum levels of triglycerides (TAG), non-esterified fatty acids (NEFA), leptin (LEP) and adiponectin were measured. The results of the analyzed measurements showed an increase in GrN (P<0.05) in the PC, PT, PA and NEFA variables between the 8th and 9th month of pregnancy. Although there was an increase (P<0.01) between the 8th and 11th month of pregnancy in the EGBC variable, in GrO the PA was increased (P<0.01) between the 8th and 11th month of pregnancy and the LEP showed an increase (P<0.05) between the 10th and 11th month. When both groups were compared, the variables PC, PT, EGBC and EGRP showed differences (P<0.05) in all months evaluated. In the correlation the BCS was associated with PC (r=0.691, P<0.0001), PT (r=0.705, P<0.0001), EGBC (r=0.701, P<0.0001), EGRP (r=0.627, P<0.0001), serum leptin levels (r=0.426, P<0.0001) and adiponectin (r=0.217, P<0.05). Thus, it can be stated that the body fat increased progressively in mares GrN, different from that observed in GrO. Therefore, by the methods used in this study, the morphometry practical evaluation of the Crioula breed mares in the last third of gestation became possible, allowing an objective way to identify obese individuals(AU)

Medidas comparativas do padrão morfométrico e perfil energético de éguas crioulas no terço final da gestação, com diferentes escores corporais / Comparative measurements of the morphometric pattern and energy profile of crioula mares in the final third of gestation, with different body condition scores

O objetivo deste estudo é comparar e descrever medidas morfométricas e perfil energético de éguas da raça Crioula no terço final da gestação. Foram utilizadas vinte éguas gestantes, divididas em 2 grupos conforme o escore corporal (BCS); o GrN (n=10), grupo de éguas com BCS 5 ou moderado, e GrO (n=10), grupo de éguas obesas ou BCS 9, analisadas conforme o mês de gestação (8º, 9º, 10º e 11º). Foram realizadas coletas de sangue e avaliações morfométricas mensais do peso corporal (PC), perímetro torácico (PT), perímetro abdominal (PA), altura da crista do pescoço (AC), espessura de gordura subcutânea na base da cauda (EGBC) e espessura de gordura retroperitoneal (EGRP). Para avaliar o perfil energético, foram mensurados os níveis séricos de triglicerídeos (TAG), ácidos graxos não esterificados (NEFA), Leptina (LEP) e Adiponectina. Os resultados das mensurações analisadas demonstraram no GrN incremento (P<0,05) nas variáveis PC, PT, PA e NEFA do 8º para o 9º mês de gestação. Porém, na variável EGBC, o aumento (P<0,01) foi observado entre o 8º e o 11º mês avaliado. No GrO, o PA demonstrou incremento (P<0,01) entre o 8º e o 11º mês de gestação, e a LEP apresentou aumento (P<0,05) entre o 10º e o 11º mês. Quando os dois grupos foram comparados, as variáveis PC, PT, EGBC e EGRP apresentaram diferença (P<0,05) em todos os meses avaliados. Na análise de correlação, o BCS associou-se com o PC (r=0,691; P<0,0001), PT (r=0,705; P<0,0001), EGBC (r=0,701; P<0,0001), EGRP (r=0,627; P<0,0001), níveis séricos de LEP (r=0,426; P<0,0001) e Adiponectina (r=0,217; P<0,05). Dessa forma, pode-se afirmar que a gordura corporal aumentou progressivamente nas éguas do GrN, diferentemente do observado no GrO. Através dos métodos utilizados neste trabalho, torna-se possível a avaliação prática da morfometria das éguas da raça Crioula no terço final da gestação, possibilitando de forma objetiva a identificação de indivíduos obesos.

The aim of this study was to compare and describe morphometric measurements and energy profile of the Crioula breed mares at the end of gestation. Twenty pregnant mares were used and separated into 2 groups according to body condition score (BCS). The GrN (n= 10) group of mares with BCS 5 or moderate and GrO (n = 10) group of obese mares or BCS 9 were analyzed according to the month of pregnancy (8th, 9th, 10th and 11th). Blood samples and monthly morphometric evaluation were performed for body weight (PC), heart girth (PT), waist circumference (PA), height of the crest of the neck (AC), thickness subcutaneous fat on the base of the tail (EGBC) and retroperitoneal (EGRP). To evaluate the energy profile serum levels of triglycerides (TAG), non-esterified fatty acids (NEFA), leptin (LEP) and adiponectin were measured. The results of the analyzed measurements showed an increase in GrN (P<0.05) in the PC, PT, PA and NEFA variables between the 8th and 9th month of pregnancy. Although there was an increase (P<0.01) between the 8th and 11th month of pregnancy in the EGBC variable, in GrO the PA was increased (P<0.01) between the 8th and 11th month of pregnancy and the LEP showed an increase (P<0.05) between the 10th and 11th month. When both groups were compared, the variables PC, PT, EGBC and EGRP showed differences (P<0.05) in all months evaluated. In the correlation the BCS was associated with PC (r=0.691, P<0.0001), PT (r=0.705, P<0.0001), EGBC (r=0.701, P<0.0001), EGRP (r=0.627, P<0.0001), serum leptin levels (r=0.426, P<0.0001) and adiponectin (r=0.217, P<0.05). Thus, it can be stated that the body fat increased progressively in mares GrN, different from that observed in GrO. Therefore, by the methods used in this study, the morphometry practical evaluation of the Crioula breed mares in the last third of gestation became possible, allowing an objective way to identify obese individuals.

Optimal rectification in the ultrastrong coupling regime.

We study the effect of ultrastrong coupling on the transport of heat. In particular, we present a condition for optimal rectification, i.e., flow of heat in one direction and complete isolation in the opposite direction. We show that the strong-coupling formalism is necessary for correctly describing heat flow in a wide range of parameters, including moderate to low couplings. We present a situation in which the strong-coupling formalism predicts optimal rectification whereas the phenomenological approach predicts no heat flow in any direction, for the same parameter values.

Improved tretinoin photostability in a topical nanomedicine replacing original liquid suspension with spray-dried powder with no loss of effectiveness.

OBJECTIVE: The use of spray-dried powders containing tretinoin-loaded nanocapsules instead of the original liquid suspension, aimed at the preparation of dermatological nanomedicines with improved photostability, was investigated. METHODS: Powders were prepared using lactose as a drying adjuvant. Hydrogels were prepared using two approaches: dispersing Carbopol Ultrez 10 in an aqueous redispersion of the powder or incorporating the powder in previously formed hydrogels. RESULTS AND DISCUSSION: The photodegradation of tretinoin in hydrogels prepared with the powders showed similar half-life times (around 19.5 h) compared to preparations with the original liquid nanocapsules (20.7 ± 1.4 h), regardless of the preparation approach. In addition, the topical nanomedicines prepared with the spray-dried powders presented a significant improvement in tretinoin photostability compared to the formulation containing the non-encapsulated drug. CONCLUSION: This study verified that the addition of the spray-dried powders containing tretinoin-loaded lipid-core nanocapsules to hydrogels did not influence the photoprotection of the drug compared with the preparation procedure using the original liquid suspension.

Spray-dried powders containing tretinoin-loaded engineered lipid-core nanocapsules: development and photostability study.

The influence of the spray-drying process on the ability of engineered lipid-core nanocapsules to protect tretinoin against UV degradation was evaluated. This approach represents a technological alternative to improve the microbiological stability, storage and transport properties of such formulations. Tretinoin-loaded lipid-core nanocapsules or tretinoin-loaded nanoemulsion were dispersed in lactose (10% w/v) and fed in the spray-drier to obtain a solid product (spray-dried powder containing tretinoin-loaded nanocapsules or nanoemulsion--SD-TTN-NCL or SD-TTN-NE, respectively). SD-TTN-NE showed a lower (p < or = 0.05) percentage of encapsulation (89 +/- 1%) compared to SD-TTN-NCL (94 +/- 2%). Redispersed SD-TTN-NCL and SD-TTN-NE showed z-average sizes of 204 +/- 2 nm and 251 +/- 9 nm, which were close to those of the original suspensions (220 +/- 3 nm and 239 +/- 14 nm, respectively). Similar percentage of photodegradation were determined for tretinoin loaded in nanocapsules (26.15 +/- 4.34%) or in the respective redispersed spray-dried powder (28.73 +/- 6.19 min) after 60 min of UVA radiation exposure (p > 0.05). Our experimental design showed for the first time that spray-dried lipid-core nanocapsules are able to protect tretinoin against UVA radiation, suggesting that the drying process did not alter the supramolecular structure of the lipid-core nanocapsules. Such powders are potential intermediate products for the development of nanomedicines containing tretinoin.

Energy transfer dynamics and thermalization of two oscillators interacting via chaos.

We consider the classical dynamics of two particles moving in harmonic potential wells and interacting with the same external environment HE, consisting of N noninteracting chaotic systems. The parameters are set so that when either particle is separately placed in contact with the environment, a dissipative behavior is observed. When both particles are simultaneously in contact with HE an indirect coupling between them is observed only if the particles are in near-resonance. We study the equilibrium properties of the system considering ensemble averages for the case N=1 and single trajectory dynamics for N large. In both cases, the particles and the environment reach an equilibrium configuration at long times, but only for large N can a temperature be assigned to the system.

Energy dissipation via coupling with a finite chaotic environment.

We study the flow of energy between a harmonic oscillator (HO) and an external environment consisting of N two-degrees-of-freedom nonlinear oscillators, ranging from integrable to chaotic according to a control parameter. The coupling between the HO and the environment is bilinear in the coordinates and scales with system size as 1/√N. We study the conditions for energy dissipation and thermalization as a function of N and of the dynamical regime of the nonlinear oscillators. The study is classical and based on a single realization of the dynamics, as opposed to ensemble averages over many realizations. We find that dissipation occurs in the chaotic regime for fairly small values of N, leading to the thermalization of the HO and the environment in a Boltzmann distribution of energies for a well-defined temperature. We develop a simple analytical treatment, based on the linear response theory, that justifies the coupling scaling and reproduces the numerical simulations when the environment is in the chaotic regime.

Use of lidocaine hydrochloride 2% intrathecally associated with prior anesthesia with thiopental as a method of euthanasia in horses / Utilização de lidocaína 2% por via intratecal associado à anestesia prévia com tiopental sódico como método de eutanásia em equinos

The aim of this study was to evaluate the efficiency of intrathecal lidocaine preceded by pre-anesthesia using intravenous sodium thiopental as euthanasia protocol in horses presenting different degrees of awareness and clinical condition. Twenty two horses that were admitted to the HCV-UFPel and sent to euthanasia after clinical evaluation, were used in the study. Clinical general and specific examinations were performed to classify the horses according to their clinical condition and level of consciousness on a scale from 1 to 3. The time to cardiac arrest and other reactions during euthanasia was monitored. The moment of cardiac arrest was not influenced by clinical condition, disease or dose of sodium thiopental. It was observed that the higher the volume of intrathecal lidocaine, the shorter the time to cardiac arrest (P<0.05). The post-euthanasia histopathological analysis of the central nervous system indicated that this technique did not cause macro or microscopic injuries to the tissue. Thus, intrathecally lidocaine associated with sodium thiopental pre-anesthesia was effective as equine euthanasia protocol, since it promoted rapid unconsciousness with mild reactions and insensitivity, without causing injuries in the central nervous system as well.

O objetivo deste trabalho foi avaliar eficiência da utilização de lidocaína por via intratecal, associada à anestesia prévia com thiopental sódico endovenoso, como método de eutanásia em equinos com diferentes graus de consciência e condição clínica. Foi utilizada a rotina clinica do HCV-UFPel, onde foram avaliados 22 eqüinos os quais apresentavam indicação de eutanásia. Foi realizado exame clínico geral e específico, classificando a condição clínica e grau de consciência, numa escala de 1 a 3. Foi monitorado o tempo para ocorrência de parada cardíaca e a ocorrência de reações durante o período trans-eutanásia. O tempo para parada cardíaca não foi influenciado pela classificação clínica, tipo de doença ou dose do tiopental sódico. Foi observado que quanto maior o volume de lidocaína utilizada por via intratecal, menor é o tempo para parada cardíaca (p<0,05). A análise histopatológica do sistema nervoso central pós-eutanásia demonstrou que a técnica não causou lesões macro e microscópicas. Assim, a utilização da lidocaína via intratecal associada a pré anestesia com tiopental sódico, mostrou-se eficaz na eutanásia de equinos, proporcionando uma inconsciência rápida, com discretas reações e insensibilidade, além de não causar lesões ao sistema nervoso central.

USE OF LIDOCAINE HYDROCHLORIDE 2% INTRATHECALLY ASSOCIATED WITH PRIOR ANESTHESIA WITH THIOPENTAL AS A METHOD OF EUTHANASIA IN HORSES / Utilização de lidocaína 2% por via intratecal associado à anestesia prévia com tiopental sódico como método ...

O objetivo deste trabalho foi avaliar eficiência da utilização de lidocaína por via intratecal, associada à anestesia prévia com thiopental sódico endovenoso, como método de eutanásia em eqüinos com diferentes graus de consciência e condição clínica. Foi utilizada a rotina clinica do HCV-UFPel, onde foram avaliados 22 eqüinos os quais apresentavam indicação de eutanásia. Foi realizado exame clínico geral e específico, classificando a condição clínica e grau de consciência, numa escala de 1 a 3. Foi monitorado o tempo para ocorrência de parada cardíaca e a ocorrência de reações durante o período trans-eutanásia. O tempo para parada cardíaca não foi influenciado pela classificação clínica, tipo de doença ou dose do tiopental sódico. Foi observado que quanto maior o volume de lidocaína utilizada por via intratecal, menor é o tempo para parada cardíaca (p 0,05). A análise histopatológica do sistema nervoso central pós-eutanásia demonstrou que a técnica não causou lesões macro e microscópicas. Assim, a utilização da lidocaína via intratecal associada a pré anestesia com tiopental sódico, mostrou-se eficaz na eutanásia de eqüinos, proporcionando uma inconsciência rápida, com discretas reações e insensibilidade, além de não conferir lesões ao sistema nervoso central. SummaryThe aim of this study was to evaluate the efficiency of intrathecal lidocaine preceded by pre-anesthesia us

USE OF LIDOCAINE HYDROCHLORIDE 2% INTRATHECALLY ASSOCIATED WITH PRIOR ANESTHESIA WITH THIOPENTAL AS A METHOD OF EUTHANASIA IN HORSES / Utilização de lidocaína 2% por via intratecal associado à anestesia prévia com tiopental sódico como método ...

O objetivo deste trabalho foi avaliar eficiência da utilização de lidocaína por via intratecal, associada à anestesia prévia com thiopental sódico endovenoso, como método de eutanásia em eqüinos com diferentes graus de consciência e condição clínica. Foi utilizada a rotina clinica do HCV-UFPel, onde foram avaliados 22 eqüinos os quais apresentavam indicação de eutanásia. Foi realizado exame clínico geral e específico, classificando a condição clínica e grau de consciência, numa escala de 1 a 3. Foi monitorado o tempo para ocorrência de parada cardíaca e a ocorrência de reações durante o período trans-eutanásia. O tempo para parada cardíaca não foi influenciado pela classificação clínica, tipo de doença ou dose do tiopental sódico. Foi observado que quanto maior o volume de lidocaína utilizada por via intratecal, menor é o tempo para parada cardíaca (p < 0,05). A análise histopatológica do sistema nervoso central pós-eutanásia demonstrou que a técnica não causou lesões macro e microscópicas. Assim, a utilização da lidocaína via intratecal associada a pré anestesia com tiopental sódico, mostrou-se eficaz na eutanásia de eqüinos, proporcionando uma inconsciência rápida, com discretas reações e insensibilidade, além de não conferir lesões ao sistema nervoso central. SummaryThe aim of this study was to evaluate the efficiency of intrathecal lidocaine preceded by pre-anesthesia us

Lipid-core nanocapsules as a nanomedicine for parenteral administration of tretinoin: development and in vitro antitumor activity on human myeloid leukaemia cells.

Tretinoin-loaded conventional nanocapsules have showed a significant protection of this drug against UVC radiation. However, this formulation presents a limited stability on storage. We hypothesized that the association of tretinoin to lipid-core nanocapsules could increase the physicochemical stability of such formulations, focusing on the development of a reliable nanomedicine for parenteral administration. However, this advantage should still be accompanied by the known photoprotective effect of conventional polymeric nanocapsules against the exposure of tretinoin to UV radiation. Results showed that tretinoin-loaded lipid-core nanocapsules improved the physicochemical stability of formulations under storage, without changing their ability to protect tretinoin either against UVA or UVC radiation. In addition, the effect of nanoencapsulation on the antiproliferative and differentiation properties of tretinoin was studied on human myeloid leukemia cells (HL60 cells) showing that tretinoin-loaded lipid-core nanocapsules presents a longer antitumor efficiency compared to the free tretinoin. These results allow us to propose the current formulation (tretinoin-loaded lipid-core nanocapsules) as a promising parenteral nanomedicine for the treatment of acute promyelocytic leukaemia.

Hydrogel containing dexamethasone-loaded nanocapsules for cutaneous administration: preparation, characterization, and in vitro drug release study.

CONTEXT: Our group previously reported the development of dexamethasone-loaded polymeric nanocapsules as an alternative for topical dermatological treatments. OBJECTIVE: Our study aimed to prepare and characterize a hydrogel containing this system to improve the effectiveness of the glucocorticoid for cutaneous disorders. METHODS: For the antiproliferative activity assay, a dexamethasone solution and D-NC were tested on Allium cepa root meristem model. D-NC were prepared by the interfacial deposition of preformed polymer. Hydrogels were prepared using Carbopol Ultrez 10 NF, as polymer, and characterized according to the following characteristics: pH, drug content, spreadability, viscosity, and in vitro drug release. RESULTS AND DISCUSSION: Nanocapsules showed mean particle size and zeta potential of 201 +/- 6 and -5.73 +/- 0.42 nm, respectively. They demonstrated a lower mitotic index (4.62%) compared to free dexamethasone (8.60%). Semisolid formulations presented acidic pH values and adequate drug content (between 5.4% and 6.1% and 100% and 105%, respectively). The presence of nanocapsules in hydrogels led to a decrease in their spreadability factor. Intact nanoparticles were demonstrated by TEM as well as by dynamic light scattering (mean particle size < 300 nm). In vitro studies showed a controlled dexamethasone release from hydrogels containing the drug associated to the nanocapsules following the Higuchi's squared root model (k = 20.21 +/- 2.96 mg/cm(2)/h(1/2)) compared to the hydrogels containing the free drug (k = 26.65 +/- 2.09 mg/cm(2)/h(1/2)). CONCLUSION: Taking all these results together, the hydrogel containing D-NC represent a promising approach to treat antiproliferative-related dermatological disorders.

[Heart rupture in acute myocardial infarct: the advantages of using M-2D color Doppler echocardiography in a coronary intensive therapy unit]. / Rottura di cuore nell'infarto acuto del miocardio: vantaggi dell'uso dell'ecocardiografia M-2D color Doppler in unità di terapia intensiva coronarica.

BACKGROUND: Free-wall rupture of the heart is the second most common cause of death in acute myocardial infarction (AMI), following pump failure. Acute rupture is more common and rapidly fatal, while subacute rupture, which accounts for about 30% of total cases of mortality in AMI, can be diagnosed early by clinical signs with the support of echocardiography in coronary intensive care units. METHODS: From March 1996 to December 1997, 293 patients diagnosed with acute myocardial infarction were admitted to the coronary intensive care unit of our hospital. Of these patients, 71 (23.8%) were treated with thrombolysis within 6 hours of onset of symptoms. All patients were observed daily with M-2D color Doppler echocardiography and in the event of renewed chest pain, electrocardiogram changes, abrupt hypotension, syncope or clinical signs of low output syndrome. RESULTS: We observed 11 cases (3.8%) of free-wall rupture of the heart in acute myocardial infarction with echocardiography, 6 females and 5 males, with a mean age of 74.2 +/- 7.8 years (min. 56-max 84), none of whom had prior AMI. Six of them received thrombolytic therapy, six were hypertensive (54.5%) and three were diabetics (27.2%). Surgical repair was performed in two patients with subacute rupture, but one died a few days later. The echocardiography data at bedside for diagnosis of cardiac rupture were confirmed in 5 patients with autopsy and intraoperatively in two of them. CONCLUSIONS: Routine use of echocardiography in coronary intensive care units allows prompt diagnosis of cardiac rupture in acute myocardial infarction, and in the event of subacute rupture it can accelerate surgical decision-making.

Laparoscopic colorectal procedures: a multicenter Brazilian experience.

An evaluation of the results of the Brazilian experience in colorectal laparoscopic procedures in a multicenter prospective protocol done by the Brazilian Society of Colo-Proctology is presented. From December 1991 to August 1998, 1,161 patients (583 men and 578 women; mean age, 49.8 years), were operated on laparoscopically. Most of the procedures (40.5%) were for cancer, and the most common procedure was anterior resection (22.5%). The mean operative time was 189 minutes (3.1 hours). There were 42 (3.6%) perioperative complications; visceral injuries were the most common (1.4%). Conversions occurred in 122 (10.5%) cases. There were 148 (12.7%) postoperative complications; wound infections were the most common (5.2%). A liquid diet was started at a mean time of 1.4 days after the operation, and the mean hospitalization period was 6.4 days.

[Acute toxicity of ammonia in the production process of postlarvae of Penaeus paulensis Pérez-Farfante, 1967]. / Toxicidade aguda da amônia no processo produtivo de pós-larvas de Penaeus paulensis Pérez-Farfante, 1967.

Larval shrimp Penaeus paulensis showed a tendency to decrease in ammonia tolerance as the larva metamorphosed from nauplius to postlarvae stage. The 24-h LC50 were 4.04, 1.70, 2.72, and 1.42 mg/l NH3-N on nauplii, zoea, mysis and postlarvae, respectively. The zoea stage and the initial postlarvae substages were very susceptible to ammonia. The 96-h LC50 values on zoea and postlarvae were 0.69 mg/l and 0.32 mg/l, against 0.80 mg/l NH3-N on mysis. The eggs of Penaeus paulensis were very affected by ammonia, which provoked a progressive decrease in the hatching rate and induced morphological deformities in hatched nauplii. A "safe level" of ammonia was estimated at 0.032 mg/l NH3-N on the basis of 24-h LC50 for eggs.

[The P loop in atrioventricular septal defect. Embryologico-vectorcardiographic correlation]. / El asa P en el defecto del septum atrio-ventricular. Correlación embriológico-vectocardiográfia.

Atrial vectorcardiograms (vcg) were analysed in 23 patients with partial (n = 15) or complete (n = 8) forms of atrioventricular septal defect (AVSD). The rotation and the projection of the maximum left atrial vector (MLAV) on the frontal plane (FP) and on the horizontal plane (HP) were noted. To assess the possible influence of the degree of left-to-right shunting and the right atrial and right ventricular pressures on the rotation and MLAV projection, these vcg data were correlated with hemodynamic values obtained at the time of preoperative cardiac catheterization. Vcg characteristics of the patients were also compared with those of 25 healthy individuals. No significant differences were noted between the vcg of patients with the partial form and those with the complete form of AVSD. Also, there was no apparent influence of the hemodynamic values on the loop rotation or the MLAV projection in either plane among the patients. However, the MLAV showed a more posteriorly and superior location in the FP and HP than in normal subjects (p = 0.0001). Moreover, 67% of the cases showed a clockwise rotation of the loop in the HP and 33% in the FP; in contrast, normal subjects always showed a counterclockwise rotation in both planes. A more posterior and superior MLAV is consistent with direct observations in human embryos with AVSD which have shown that deficiencies of the posterior portion of the interventricular septum are the basic feature in all cases. The adaptation of the conductive tissue to such deficiency occurs in early phases of cardiac development.