Recuperação anestésica e analgesia residual da infusão continua intravenosa de fantanil, lidocaína, cetamina e fentanyl-lidocaína-cetamina associados à anesthesia total intravenosa com Propofol em cadelas submetidas à ovariossalpingo-histerectomia eletiva / Anesthetic recovery and residual analgesia of constant rate infusion intraoperative of fentanyl, lidocaine, ketamine or fentanyl-lidocaine-ketamine associated with total intravenous anesthesia with propofol in bitches submitted to elective ovariohysterectomy

Avaliou-se a recuperação anestésica e a analgesia residual da infusão contínua (IC) de fentanil (F), lidocaína (L), cetamina (K) e fentanil-lidocaína-cetamina (FLK), associados à anestesia total intravenosa com o propofol, em cadelas submetidas à ovariossalpingo-histerectomia. Foram utilizados 32 animais pré-medicados com acepromazina, distribuídos em quatro grupos de acordo com o tratamento analgésico: F: bolus de 0,0036mg/kg de fentanil e IC de 0,0036mg mg/kg/h; L: bolus de 3mg/kg de lidocaína e IC de 3mg/kg/h; K: bolus de 0,6mg/kg de cetamina e IC de 0,6mg/kg/h; e FLK: bolus e IC dos três fármacos nas doses supracitadas. Após o bolus do tratamento analgésico, foi realizada a indução e o início da IC do tratamento analgésico e do propofol. Para avaliação da recuperação anestésica, foram considerados os tempos de extubação, decúbito esternal, posição quadrupedal e os efeitos adversos. A avaliação da analgesia foi realizada por meio da escala visual analógica e modificada de Glasgow, durante seis horas. Os efeitos adversos observados foram vômito, sialorreia e tremor muscular. Receberam analgesia de resgate 100% dos animais do grupo F, 87,5% do K, 50% do L e 12,5% do FLK. O FLK demonstrou maior analgesia, e a recuperação anestésica foi semelhante em todos os grupos.(AU)

The anesthetic recovery and residual analgesia of continuous rate infusion (CRI) of fentanyl (F), lidocaine (L), ketamine (K) and fentanyl-lidocaine-ketamine (FLK) associated with total intravenous anesthesia with propofol in bitches submitted to ovariohysterectomy were evaluated. 32 animals were used, pre-medicated with acepromazine and distributed into four groups according to analgesic treatment: F loading dose (LD) of 0.0036mg/kg fentanyl, and CRI of 0.0036mg/kg/h, L: LD of 3mg/kg lidocaine, and CRI of 3mg/kg/h; K: LD of 0.6mg/kg ketamine, and CRI of 0.6mg/kg/h and FLK: LD and CRI of the three drugs in the above mentioned doses. After the LD of analgesic treatment, the induction was performed and the CRI of the analgesic treatment and propofol started. To evaluate the anesthetic recovery, the time of extubation, sternal decubitus, quadrupedal position and adverse effects were considered. The analgesia evaluation was performed using the visual scale and modified Glasgow for six hours. The adverse effects observed were vomiting, sialorrhea and muscle tremor. 100% of the animals in group F, 87.5% of K, 50% of L and 12.5% of FLK received rescue analgesia. FLK demonstrated greater analgesia, and anesthesia recovery was similar in all groups.(AU)

Estudo comparativo entre métodos manual e digital no cálculo do ângulo do platô tibial em cães / Comparative study of manual and digital method in the calculation of the tibial plateau angle in dogs

São poucos os dados publicados sobre a aplicabilidade ou a confiabilidade dos métodos digitais para mensuração do ângulo do platô tibial (APT) em comparação à mensuração manual. O objetivo deste estudo foi comparar o APT obtido pelo cálculo manual padrão, em filmes radiográficos, com os valores obtidos por cálculos em imagens digitais, por meio do software do computador. Foram analisadas radiografias digitais do membro pélvico, direito e esquerdo, em perfil verdadeiro, de 20 cães saudáveis, com idade superior a um ano. Três observadores com graus de experiência semelhantes em cálculo do APT realizaram as mensurações em cada radiografia. Primeiramente, foram calculados os ângulos dos platôs tibiais manualmente nas películas radiográficas e, posteriormente, os cálculos foram realizados na imagem digital, por meio do software para medicina veterinária do sistema de raios X digital. Os resultados do presente estudo demonstraram diferenças significativas entre os métodos, com valor das médias do cálculo digital 20,48±3.71 e do cálculo manual 23.90±4.02. Valor de P foi < 0,01 na comparação entre médias dos dois grupos. Na avaliação interobservadores, houve diferença significativa no cálculo manual no perfil direito, o que sugere maior variação no cálculo manual quando comparado ao digital. O cálculo realizado pelo software apresentou menor variação nos valores interobservadores. Acredita-se que a menor variação obtida nos resultados aqui apresentados se dê em razão das facilidades proporcionadas pelo software. Conclui-se que houve diferença entre os valores obtidos por meio dos métodos convencional e digital no cálculo do ângulo do platô tibial, sendo os valores digitais menores entre os observadores, e que o método digital no cálculo do ângulo do platô tibial levou à menor variação quando comparado ao método manual.(AU)

There are few published data on the applicability and reliability of digital methods for measuring the TPA compared with manual measurement. The objective of this study was to compare the TPA obtained by calculating standard manual on conventional radiographs, with the values obtained by calculations in digital images through a computer program. Bilateral digital radiographs of hind limb were analyzed in true profile for 20 healthy dogs older than two years. Three observers with similar levels of experience in calculating the TPA conducted measurements on each radiograph. First we calculated the angle of the tibial plateaus manually in x-ray film and then the calculations were made through the program offered by the computer program in the digital image. The results of this study showed significant differences between the methods, with average value of 20.48±3.71 digital calculating average and 23.90±2.4 in the manual calculation. P value was < 0.01 when comparing averages. No significant difference in manual calculation in right profile were found between interobserver assessments, suggesting greater variation in manual calculation compared to digital. The calculation performed by the software showed less variation in values. The slight variation obtained in our results is believed to be due to the facilities provided by the software. There was a difference between the values obtained by means of conventional and digital methods for calculating the angle of the tibial plateau, and the smaller digital values between the observers and the digital method in the calculation of the tibial plateau angle led to less variation when compared to the manual method.(AU)

Impacto do grau de uveíte em diferentes tipos de úlceras de córneas em cães submetidos ao enxerto pediculado de conjuntiva bulbar - 34 casos / Impact of uveitis score on different types of corneal ulcers in dogs subjected to the bulbar conjunctival pedicle graft - 34 cases

O presente trabalho objetivou avaliar os resultados de 34 olhos submetidos ao enxerto conjuntival pediculado (ECP) em ceratites ulcerativas profundas (n=5), em ceratites ulcerativas com colagenólise (n=2), descemetocele (n=7), perfuração corneal (n=15) e prolapso de íris (n=5). Os impactos do grau de uveíte e da integridade da córnea foram correlacionados com presença e ausência de visão por tabelas de contingência. Raças braquicefálicas foram acometidas em 91,11% dos casos. O número de córneas consideradas perfuradas [20/34 (58,82%)] foi maior que o de córneas íntegras [14/34 (41,17%)]. Ao 50º dia de pós-operatório, o número de olhos visuais que apresentavam córneas íntegras previamente às cirurgias (n=13) não diferiu significativamente dos olhos com córneas perfuradas (n=12) (P=0,05). Avaliações relativas ao grau de uveíte, revelaram que a metade dos casos foi considerada severa [17/34 (50%)] e na outra metade as uveítes foram consideradas discretas. Dos 17 casos que apresentaram uveíte severa, oito recuperaram a visão. Já nos 17 olhos onde a uveíte foi considerada leve, 15 mantiveram a visão ao final do período de avaliação. Apesar de a integridade da córnea não se correlacionar com a severidade da uveíte (P=0,48), constatou-se que o número de olhos visuais com uveíte discreta foi significativamente maior que os olhos com uveíte severa (P=0,006). Neste estudo, a taxa geral de sucesso visual após ECP foi de 73,52% e a integridade da córnea não exerceu impacto significativo sobre a manutenção da visão. Todavia, olhos acometidos por uveítes severas apresentaram menor chance de recuperar a visão.(AU)

The present study aimed to evaluate the results of 34 eyes of dogs presenting deep corneal ulcer (n=5), colagenolytic corneal ulcer (n=2), descemetocele (n=7), corneal perforation (n=15), and iris prolapse (n=5) that were corrected by the bulbar conjuntival pedicle graft (CPG). The uveitis score and the corneal integrity were correlated with the presence or absence of vision by contingency tables. Brachycephalic breeds accounted for 91.11% of all cases. The number of perforated corneas [20/34 (58.82%)] were higher than the non-perforated ones [14/34 (41.17%)]. At post-operative day 50, the number of visual eyes with non-perforated corneas before surgery (n=13) did not differ significantly from the eyes with perforated corneas (n=12) (P = 0.05). In half of the cases, uveitis score was considered severe [17/34 (50%)], and in the other half, mild. Eight out of 17 eyes classified with severe uveitis regained vision. In 17 eyes where uveitis score was considered mild, 16 regained vision at the end of the study. Although corneal integrity was non-correlated with the uveitis score (P = 0.48), the number of visual eyes scored with mild uveitis were significantly larger than the eyes with severe uveitis (P = 0.006). In this study, the overall success visual rate after CPG was 73,52% % and the corneal integrity did not play an important role regarding maintenance of vision. However, eyes presenting severe uveitis score had less chance to regain vision.(AU)

Influência do posicionamento radiográfico no cálculo interobservador do ângulo do platô tibial em cães / Influence of radiographic positioning in the interobserver measuring of the tibial plateau angle in dogs

O objetivo deste trabalho foi demonstrar que o posicionamento radiográfico inadequado do membro pélvico de cães (imagens obliquadas) afeta a mensuração do ângulo do platô tibial (APT), levando à maior variação entre observadores. Foram realizadas duas projeções radiográficas nos membros pélvicos direito e esquerdo, uma em perfil verdadeiro e a outra com o membro obliquado em 21 cães provenientes do atendimento clínico cirúrgico do Hospital Veterinário da Universidade de Cuiabá, em Cuiabá-MT. Os critérios de inclusão foram cães livres de histórico ou afecção ortopédica nos membros pélvicos, pesando entre 15 e 40 quilos, sem predileção por raça ou sexo, entre dois e sete anos de idade. Foram obtidas 42 imagens radiográficas em perfil verdadeiro e 42 imagens radiográficas obliquadas. Três observadores com experiência em cálculo do APT fizeram as mensurações. Nos cálculos das imagens em perfil verdadeiro, o observador 1 obteve uma média de 23,35º ± 2,82; o observador 2, média de 23,88º ± 4,83; e o observador 3, média de 24,54º ± 4,01, não sendo encontrada diferença significativa entre o cálculo dos três avaliadores, P=0,944 (P > 0,05), nas imagens em perfil verdadeiro. Nos cálculos das imagens obliquadas, o observador 1 obteve uma média de 21,69º ± 4,22; o observador 2, média de 19,42º ± 5,92; e o observador 3, média de 22,64º ± 5,23, e foi encontrada diferença significativa entre o cálculo dos três observadores, P=0,016 (P < 0,05). Com esses dados, pôde-se demonstrar que a imagem radiográfica obliquada compromete o valor final do cálculo do ângulo do platô tibial em cães, levando à variação numérica estatisticamente significativa entre observadores. Conclui-se, assim, que um posicionamento correto do membro pélvico, em perfil verdadeiro, deve ser sempre utilizado para a obtenção de imagens, com o objetivo de mensurar o valor do APT.(AU)

This work aimed at demonstrating that an inadequate radiographic position of pelvic limbs of dogs, from a strict lateral radiographic view, resulted in oblique images, affecting the measurement of the tibial plateau angle (TPA). There were two radiographic projections of the right and the left pelvic limb, one in strict lateral radiographic view and another with inclined hind limb in 21 dogs from the clinical surgical assistance at Hospital Veterinário of Universidade de Cuiabá in Cuiabá-MT. Inclusion criteria were dogs free from pelvic hind limbs orthopedic affection records, weighing between 15 and 40 kilos, without a preference for breed or gender and ageing between two and seven years old. A total of 42 radiographic images in strict lateral radiographic view and 42 inclined limb radiographic views were obtained. Three observers with TPA calculation experience made measurements. In the calculus for the strict lateral radiographic view the first observer has reached an average of 23,35º ± 2,82, the second observer 23,88º ± 4,83 and the third observer 24,54º ± 4,01. No significant statistic differences among the calculus of the three evaluators p=0,944 (P>0,05) was found. In the calculus of the inclined limbs radiographic views the first observer reached an average of 21,69º ± 4,22, the second observer 19,42º ± 5,92 and the third observer 22,64º ±. 5,23. Significant statistic difference in the calculus of the three observers, p=0,016, that is to say, P<0,05 was found. The data indicated that the inclined limb radiographic image compromises the final value of the calculation of tibial plateau angle in dogs. Thus, correct positioning of the pelvic limb, in a strict lateral radiographic view, must be always used for obtaining images aiming at measuring the value of TPA.(AU)

Genetic analysis of inherited bone marrow failure syndromes from one prospective, comprehensive and population-based cohort and identification of novel mutations.

INTRODUCTION: Inherited bone marrow failure syndromes (IBMFSs) often have substantial phenotypic overlap, thus genotyping is often critical for establishing a diagnosis. OBJECTIVES AND METHODS: To determine the genetic characteristics and mutation profiles of IBMFSs, a comprehensive population-based study that prospectively enrols all typical and atypical cases without bias is required. The Canadian Inherited Marrow Failure Study is such a study, and was used to extract clinical and genetic information for patients enrolled up to May 2010. RESULTS: Among the 259 primary patients with IBMFS enrolled in the study, the most prevalent categories were Diamond-Blackfan anaemia (44 patients), Fanconi anaemia (39) and Shwachman-Diamond syndrome (35). The estimated incidence of the primary IBMFSs was 64.5 per 10(6) births, with Fanconi anaemia having the highest incidence (11.4 cases per 10(6) births). A large number of patients (70) had haematological and non-haematological features that did not fulfil the diagnostic criteria of any specific IBMFS category. Disease-causing mutations were identified in 53.5% of the 142 patients tested, and in 16 different genes. Ten novel mutations in SBDS, RPL5, FANCA, FANCG, MPL and G6PT were identified. The most common mutations were nonsense (31 alleles) and splice site (28). Genetic heterogeneity of most IBMFSs was evident; however, the most commonly mutated gene was SBDS, followed by FANCA and RPS19. CONCLUSION: From this the largest published comprehensive cohort of IBMFSs, it can be concluded that recent advances have led to successful genotyping of about half of the patients. Establishing a genetic diagnosis is still challenging and there is a critical need to develop novel diagnostic tools.

Comparative analysis of Shwachman-Diamond syndrome to other inherited bone marrow failure syndromes and genotype-phenotype correlation.

Our knowledge of the phenotypes of inherited bone marrow failure syndromes (IBMFSs) derives from case reports or case series in which only one IBMFS was studied. However, the substantial phenotypic overlap necessitates comparative analysis between the IBMFSs. Shwachman-Diamond syndrome (SDS) is an IBMFS that the appreciation of what comprises its clinical phenotype is still evolving. In this analysis we used data on 125 patients from the Canadian Inherited Marrow Failure Study (CIMFS), which is a prospective multicenter population-based study. Thirty-four cases of SDS patients were analyzed and compared to other patients with the four most common IBMFSs on the CIMFS: Diamond Blackfan anemia, Fanconi anemia (FA), Kostmann/severe congenital neutropenia and dyskeratosis congenita (DC). The diagnosis of SDS, FA and DC was often delayed relative to symptoms onset; indicating a major need for improving tools to establish a rapid diagnosis. We identified multiple phenotypic differences between SDS and other IBMFSs, including several novel differences. SBDS biallelic mutations were less frequent than in previous reports (81%). Importantly, compared to patients with biallelic mutations, patients with wild type SBDS had more severe hematological disease but milder pancreatic disease. In conclusion, comprehensive study of the IBMFSs can provide useful comparative data between the disorders. SBDS-negative SDS patients may have more severe hematological failure and milder pancreatic disease.

Severe prothrombin deficiency caused by prothrombin-Edmonton (R-4Q) combined with a previously undetected deletion.

BACKGROUND: During infancy, a male patient experienced several life-threatening bleeding episodes. Standard coagulation tests revealed that the patient's plasma prothrombin activity was 8%, while his father's and mother's levels were 74% and 62%, respectively. OBJECTIVES: A molecular genetic approach was used to determine the molecular basis of prothrombin deficiency within the family. PATIENT/METHODS: Prothrombin genomic DNA fragments were amplified by using the polymerase chain reaction (PCR). In addition, liver cDNA fragments were amplified from the patient by using reverse transcription (RT) and PCR. The nucleotide sequences of the DNA fragments were determined. RESULTS: A novel, heterozygous point mutation (g.1755 G > A, named prothrombin-Edmonton) was detected in the patient and his mother, resulting in the mutation of Arg-4 in the prothrombin propeptide to Gln (R-4Q). RT-PCR analysis of the patient's liver sample demonstrated the presence of two mRNA transcripts that differed by the presence or absence of exon 11. Real-time PCR analysis on genomic DNA and cDNA confirmed a deletion (g.10435_10809del) in the paternal allele. CONCLUSIONS: The patient has a maternally-inherited point mutation (R-4Q) and a paternally-inherited deletion. By analogy with the previously reported factor IX San Dimas, the R-4Q mutation probably causes under-carboxylation of prothrombin and poor cleavage of the propeptide in the hepatocyte. The deletion probably results in a polypeptide that lacks 50 amino acids from the protease domain; this is likely to impair folding, secretion, stability and/or activity of the truncated prothrombin. The two mutations combine to give the prothrombin deficiency observed in the patient.

Pneumococcal vaccines for sickle cell disease.

BACKGROUND: People with sickle cell disease are particularly susceptible to pneumococcal infection, which may be fatal. Infants (children aged up to 23 months) are at particularly high risk, but conventional polysaccharide pneumococcal vaccines may be ineffective in this age group. New conjugate pneumococcal vaccines are now available, which may help to reduce the incidence of infection in people with sickle cell disease. OBJECTIVES: To determine the efficacy of pneumococcal vaccines for reducing morbidity and mortality in people with sickle cell disease. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group trials register, comprising of references identified from comprehensive electronic database searches and hand searching relevant journals and abstract books of conference proceedings. In addition, we contacted relevant pharmaceutical companies and experts in the field.Date of most recent search of Group's trials register: November 2003. SELECTION CRITERIA: All randomised and quasi-randomised controlled trials comparing a polysaccharide or conjugate pneumococcal vaccine regimen with a different regimen or no vaccination in people with sickle cell disease. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected studies for inclusion, extracted data and assessed trial quality. MAIN RESULTS: Nine trials were identified in the searches and five trials, with a total of 547 participants, met the inclusion criteria. Only one trial reported incidence of pneumococcal infection, and this demonstrated that the polysaccharide pneumococcal vaccine used (PPV14) failed to significantly reduce the risk of infection in children under three years of age, but was associated with only minor adverse events. Three trials of conjugate pneumococcal vaccines found that immune response was increased compared to control groups, including in infants, although clinical outcomes were not measured in these trials. REVIEWER'S CONCLUSIONS: Previous trials have shown that conjugate pneumococcal vaccines are safe and effective in normal healthy patients, even those under the age of two years. The controlled trials included in this review have demonstrated immunogenicity (the body's response, without which there is no protection) of these vaccines, and observational studies in people with sickle cell disease support these findings. We therefore recommend that conjugate pneumococcal vaccines are used in people with sickle cell disease. Randomised trials in patients with sickle cell disease will be needed to determine the optimal vaccination regimen when further, potentially more effective vaccines become available. Such trials should measure clinical outcomes of effectiveness.

Presence of Ras guanyl nucleotide-releasing protein in striosomes of the mature and developing rat.

Ras signal transduction pathways have been implicated as key regulators in neuroplasticity and synaptic transmission in the brain. These pathways can be modulated by Ras guanyl nucleotide exchange factors, (GEF) which activate Ras proteins by catalysing the exchange of GDP for GTP. Ras guanyl nucleotide-releasing protein (RasGRP), a recently discovered Ras GEF, that links diacylglycerol and probably calcium to Ras signaling pathways, is expressed in brain as well as in T-cells. Here, we have used a highly selective monoclonal antibody against RasGRP to localize this protein within the striatum and related forebrain structures of developing and adult rats. RasGRP immunolabeling was found to be widespread in the mature and developing rat forebrain. Most notably, it presented a prominent patchy distribution throughout the striatum at birth and at all postnatal ages examined. These patches were found to correspond with the striosomal compartment of the striatum, as identified by micro-opioid receptor labeling in the adult. RasGRP-immunoreactivity was also observed in the matrix-like compartment surrounding these patches/striosomes but appeared later in development and was always weaker than in the patches. In both striatal compartments, RasGRP was exclusively expressed by medium-sized spiny neurons and showed no preference for neurons that project either directly or indirectly to the substantia nigra. At the ultrastructural level, immunogold labeling of RasGRP was confined to the cell bodies and dendritic shafts of these output neurons. We conclude that the prominent expression of RasGRP in striosomes may be of significance for diacylglycerol signaling in the striatum, and could be of importance for the processing of limbic-related activity within the basal ganglia.

Cellular and subcellular localization of Ras guanyl nucleotide-releasing protein in the rat hippocampus.

Ras guanyl nucleotide-releasing protein (RasGRP) is a recently discovered Ras guanyl nucleotide exchange factor that is expressed in selected regions of the rodent CNS, with high levels of expression in the hippocampus. Biochemical studies suggest that RasGRP can activate the Ras signal pathway in response to changes in diacylglycerol and possibly calcium. To investigate potential sites for RasGRP signaling, we have determined the cellular and subcellular localization of RasGRP protein in adult rat hippocampus, and have also examined the appearance of RasGRP mRNA and protein during hippocampal development. RasGRP immunoreactivity is predominately localized to those neurons participating in the direct cortico-hippocampo-cortical loop. In both hippocampal and entorhinal neurons, RasGRP protein appeared to be localized to both dendrites and somata, but not to axons. Electron microscopy of hippocampal pyramidal cells confirmed RasGRP immunoreactivity in neuronal cell bodies and dendrites, where it appeared to be associated with microtubules. The localization of RasGRP to dendrites suggests a role for this pathway in the regulation of dendritic function. Examination of developing hippocampal structures indicated that RasGRP mRNA and protein appear synchronously during the first 2 weeks of postnatal development as these neurons become fully mature. This result indicates that the RasGRP signal transduction pathway is not required during early hippocampal development, but is a feature of mature neurons during the later stages of development.

Cyclic neutropenia: an unusual disorder of granulopoiesis effectively treated with recombinant granulocyte colony-stimulating factor.

Cyclic neutropenia (CN) is a rare hematologic disorder characterized by regular cycling of the absolute neutrophil count and a symptom complex presenting during the neutropenic nadirs. Despite the profound cyclic neutropenia, most patients have a benign course of recurrent fever, malaise, oral ulceration, and minor skin and upper respiratory tract infections. Recurrent infections, inflammation, and ulcers can lead to significant chronic morbidity. Severe dental disease is common, pregnancy complications are increased, and overwhelming infections, bowel necrosis, and mortality, although rare, are potential sequelae. We report a 10-year-old boy with a classical presentation of CN that had remained undiagnosed for 10 years. The difficulty in diagnosing this unusual disorder is highlighted. Treatment with daily recombinant granulocyte colony-stimulating factor (rG-CSF) resulted in a complete clearing of symptoms and a significant increase in quality of life. The excellent clinical response of CN to rG-CSF, in the absence of major adverse effects, is strongly demonstrated by this case and supports rG-CSF as a first-line therapy for CN. The physiologic and adverse effects of rG-CSF use in CN and other neutropenic disorders, including potential leukemic induction, are reviewed. The need for long-term follow-up to investigate the effects of chronic hematopoietic stimulation by rG-CSF is emphasized.

Experience with aggressive therapy in three children with unresectable malignant liver tumors.

BACKGROUND: Children with malignant liver tumors often present with unresectable disease but need not be considered incurable. The advent of effective chemotherapy makes aggressive management feasible, as our experience with three such patients demonstrates. Procedure and Results One child with an unresectable undifferentiated sarcoma of the liver and two others with unresectable primary hepatoblastoma and lung metastases were treated with initial chemotherapy, followed by aggressive surgical management. Treatment with chemotherapy followed by hepatectomy and liver transplantation (cadaveric or live donor) in two children has resulted in disease-free survivals of 79 and 38 months. The third patient is alive and well 24 months following chemotherapy and aggressive resection of the primary and 12 metastatic lesions. CONCLUSIONS: Initial chemotherapy for unresectable liver tumors with or without metastases is supported by the review of the literature. Consideration of orthotopic liver transplantation (OLT) from cadaveric or living related donor is warranted when the malignancy is demonstrably chemosensitive, independent of initial staging. Aggressive resection of primary and metastatic disease may be called for in selected cases.

RasGRP is essential for mouse thymocyte differentiation and TCR signaling.

The Ras signaling pathway plays a critical role in thymopoiesis and T cell activation, but the mechanism of Ras regulation is controversial. At least one mode of Ras regulation in T cells involves the messenger diacylglycerol (DAG). RasGRP, a Ras activator with a DAG-binding C1 domain, is expressed in T cells and thymocytes. Here we show that thymi of RasGRP-null mutant mice have approximately normal numbers of immature thymocytes but a marked deficiency of mature, single-positive (CD4+CD8- and CD4-CD8+) thymocytes. In Ras signaling and proliferation assays, mutant thymocytes showed a complete lack of response to DAG analogs or T cell receptor (TCR) stimulation by antibodies. Thus, TCR and DAG are linked through RasGRP to Ras signaling.

Organization and chromosomal locations of Rap1a/Krev sequences in the mouse.

The human RAP1A gene encodes a protein that apparently can antagonize the function of oncogenic ras genes in gene transfer experiments, but its normal function is unknown. To understand the function of this gene, we have undertaken a study of the mouse homolog, Rap1a. The complete coding sequence of a mouse Rap1a cDNA has been determined, and genomic clones representing three distinct Rap1a species were recovered. We find that Rap1a is located on distal mouse Chromosome (Chr) 3 near Nras, Ampd-1, Tshb, Ngfb, and Atp1a1. Two related sequences (Rap1a-rs1 and Rap1a-rs2) were also characterized. Rap1a-rs1, which was not localized, has a sequence very similar to the Rap1a cDNA, suggesting that it has been recently acquired by the mouse genome. Rap1a-rs2 is more distantly related to the gene sequence and is located on Chr 2 near Actc-1.

Stability of retrovirally transduced markers in a rat cell line.

A MoMLV-based retroviral vector capable of transmitting and expressing both the human hypoxanthine phosphoribosyltransferase (hprt) coding sequence and the Herpes simplex type 1 thymidine kinase (tk) gene has been constructed. After infection of a rat cell line, cell clones were selected on the basis of expressing both markers. They were subsequently found to contain a single provirus of the expected topology. The ease with which loss of expression of the markers can be monitored has allowed us to make observations on the stability of proviral genes. In particular, we have found indirect evidence of strong position effects on proviral gene expression by comparing the characteristic frequency of marker loss in different clonal proviral lines. Effects of the selection protocol on the apparent frequency of variants have also been noted. Finally, a combination of molecular and genetic observations lead us to invoke chromosome loss as the major factor influencing marker stability in this system.

Segregation analyses and gene-centromere distances in zebrafish.

The gol-1, gol-2, alb-1 and spa-1 mutations affect pigment pattern in the zebrafish. We show here that these loci are unlinked to each other. In addition, gene-centromere distances were determined for these loci by analysis of half-tetrads obtained by the inhibition of the second meiotic division. The fractions of tetratype (second-division segregation) tetrads range from 0.24 (spa-1) to 0.89 (gol-1). The observation of greater than 0.67 second-division segregation indicates that the zebrafish has high chiasma interference.

The characterization of a mutant affecting DNA metabolism in the development of D. melanogaster.

Using a "single-fly" nucleic acid hybridization method, we have surveyed a collection of D. melanogaster strains in search of variants which affect DNA complementary to the polypyrimidine sequence corresponding to one strand of the 1.705 satellite. Hybridization of labelled polypyrimidine probe to polypurine sequence in nucleic acid extracts of single flies, followed by thermal chromatography over hydroxyapatite led to the identification of one variant. The strain Cy/M(2)S2(10) produced excess hybrid, much of which had low thermal stability. A developmental analysis of the low-melt hybrid phenotype showed that certain tissues, in particular the ovaries, were affected. In addition to the biochemical phenotype, the break down of nurse cell nuclei in Cy/M(2)S2(10) ovaries during oocyte maturation was abnormal. A genetic analysis demonstrated that both the biochemical and cytological phenotypes were the consequences of a single recessive mutation in the DNase-1 gene on chromosome III. Studies with purified DNA demonstrated that the low-melt hybrid phenotype resulted from the accumulation of low molecular weight DNA complementary to the polypyrimidine probe.

Chi activity during transduction-associated recombination.

Chi is a genetic element that stimulates phage lambda recombination by the Escherichia coli recBC pathway during lytic infection [Stahl, F. W. (1979) Annu. Rev. Genet. 13, 7--24]. Herein we show that chi in lambda prophage influences exchange distribution in P1 phage-mediated transduction and in conjugation. This demonstration encourages the view that chi may influence genetic exchange in E. coli in the total absence of lambda.

Production of clones of homozygous diploid zebra fish (Brachydanio rerio).

Homozygous diploid zebra fish have been produced on a large scale by the application of simple physical treatments. Clones of homozygous fish have been produced from individual homozygotes. These clones and associated genetic methods will facilitate genetic analyses of this vertebrate.