Influência da doença respiratória bovina e diarreia na fase de aleitamento sobre o desenvolvimento da futura vaca: Levantamento de dados

A ocorrência de diarreia e doença respiratória bovina (DRB) em bezerras resulta em impactos econômicos, reprodutivos e produtivos. O objetivo deste trabalho foi analisar o impacto da diarreia e DRB no desenvolvimento das bezerras e produção leiteira futura. O trabalho utilizou dados retrospectivos de fazenda leiteira localizada em Carambeí-PR. Todos os dados foram coletados de fêmeas bovinas da raça Holandesa, nascidas entre novembro de 2017 a novembro de 2018, sendo que estes dados estavam no software de gerenciamento Dairy Plan C21 – GEA®. Para avaliação as bezerras foram separadas em quatro grupos, sendo grupo Diarreia – bezerras com presença apenas de diarreia; grupo DRB – bezerras com presença apenas de DRB; grupo Diarreia + DRB – bezerras com presença de diarreia e DRB; grupo Saudáveis – bezerras sem doenças. No período do estudo nasceram 454 bezerras. O índice de mortalidade no aleitamento foi 9,47%. O grupo Diarreia apresentou maior taxa de morbidade (P < 0,0001). O GMD mostrou diferenças entre o grupo Diarreia + DRB e o grupo Saudáveis (P = 0,001). Bezerras do grupo DRB tiveram 2,35 mais chances de apresentar GMD abaixo de 1 kg (P < 0,001). Maior frequência de animais do grupo Saudáveis apresentou produção de leite acima de 14.000 kgna primeira lactação (P < 0,0001). Vacas com produção acima de 14.000 kg possuem 3,31 mais chances de apresentarem doenças no pós-parto em relação aos animais com produção abaixo de 10.000 kg. O grupo Saudável apresentou maior produção de leite na primeira lactação (16.410 kg) em relação ao grupo Diarreia (11.860 kg) e grupo DRB (11.263 kg) (P = 0,007). Com o trabalho concluímos que as doenças de bezerras no período de aleitamento têm impacto negativo no GMD e produção futura de leite das vacas em lactação.

Effect of prophylactic use of tulathromycin on gut bacterial populations, inflammatory profile and diarrhea in newborn Holstein calves

This objective of this study was to evaluate the use of tulathromycin on the timing of appearance and number of four indicator organisms representing the gastrointestinal microbial community, the incidence of diarrhea and a measure of the systemic inflammatory profile in Holstein heifers. Twenty-six Holstein heifer calves were distributed between receiving (ATB+) or not receiving (ATB-) tulathromycin at a dose of 2.5 mg/kg by 12 h of age. Samples from the calves were collected at six times during the neonatal period. Stool samples were used to determine the dry matter content and quantitative analysis of specific indicator bacterial populations. Samples of whole blood and serum were collected to determine the total number of neutrophils, the number of CD62L+ neutrophils, quantity of haptoglobin, and to allow for ex vivo measurement of reactive oxygen species. A higher frequency of diarrhea was detected in the ATB+ calves (84.6%) than ATB- (53.8%) on days 13-15 (P = 0.084). ATB- calves had a greater number of Bifidobacterium in stool on day 3-5 (P = 0.002), and on days 7-9 (P = 0.018). The ATB+ calves tended to have a higher number of Escherichia coli in stool on days 20-23 and days 27-30 (P = 0.052 and P = 0.072). Both the total number of neutrophils (P = 0.013) and the capacity for ROS production was higher in ATB- (P = 0.038) than ATB+ calves at all points tested. ATB+ calves had higher levels of haptoglobin (P = 0.032) on days 13-15. Administration of tulathromycin appeared to negatively impact the establishment of a normal microbiome and to modulate the development of innate immune function.

Influence of feeding fresh colostrum from the dam or frozen colostrum from a pool on indicator gut microbes and the inflammatory response in neonatal calves

The aim of this study was to evaluate the capacity of cells from colostrum to modulate the intestinal microbial colonization, the activity of the inflammatory response, and for their influence on the development of diarrheal disease in calves. Twenty calves were distributed into two groups: COL+ (n = 10) receiving fresh whole colostrum; COL- (n = 10) receiving pooled frozen colostrum, containing no viable cells. All assessments were made before colostrum intake (D0), the next day (D2), and weekly on the 7th (D7), 14th (D14), 21st (D21) and 28th (D28) day of age. Diarrhea was assessed using a fecal score, and the systemic inflammatory status was assessed using a combination of temperature, anemia, total serum iron level, total haptoglobin concentration and the need for systemic antimicrobial treatment. The number of indicator bacteria present in the fecal population was estimated using qPCR. However, COL- calves presented more frequent signs of systemic inflammatory response including, fever at D7 (P = 0.011); indicator haptoglobin levels on D7 and D14, and lower levels of iron on D7, D14. Anemia was detected more often in the COL- calves on D21 (P = 0.043) and D28 (P = 0.016). COL- calves had a 1.66 greater chance of having elevated haptoglobin and a 1.8 greater chance of needing treatment with antimicrobials than COL+. A lower number of DNA copies of Clostridium perfringens were detected in COL+ calves on D2 (P = 0.088) and D7 (P = 0.040). Similarly, a low number of DNA copies was observed for Escherichia coli and Lactobacillus spp. (P = 0.012) in the fecal samples of COL+ calves on D7.

FOTOSSENSIBILIZAÇÃO HEPATÓGENA EM BOVINOS POR INGESTÃO DE BRACHIARIA DECUMBENS

Um surto de fotossensibilização hepatógena por ingestão de Brachiaria decumbens é relatado em bovinos da raça Nelore. Após um lote de vacas e novilhas (n=320) ser transferido para um pasto de Brachiaria decumbens, vários animais começaram a apresentar diarréia, 15 apresentaram lesões de pele, que estava ressequida, enrugada com fissuras e grande quantidade de crostas, e 80 animais morreram. Foram coletadas amostras de sangue, urina e fezes de alguns animais. O hemograma apresentou alterações inespecíficas e o exame de urina e fezes estava dentro dos parâmetros aceitáveis para a espécie. Foi realizada a necropsia de um animal. O fígado apresentava coloração amarelo esverdeada. Microscopicamente havia pericolangite linfocitária multifocal leve, com tumefação difusa de hepatócitos e hepatócitos com vacuolização acentuada, bilestase difusa, presença de cristais birrefringentes e macrófagos espumosos. No rim observou-se nefrose tubular multifocal leve a moderada com presença de gotículas hialinas na luz dos túbulos, e no lúmen havia células inflamatórias, principalmente macrófagos. Após o sombreamento de algumas áreas do pasto e o inicio do tratamento com hepatoprotetor, antibióticos e limpeza das feridas os animais apresentaram melhora e não ocorreram outros casos de fotossensibilização.O diagnóstico de fotossensibilização hepatógena foi baseado nos sinais clínicos, nas lesões histológicas hepáticas e renais e no relato da transferência para um pasto de Brachiaria decumbens.

Bovine Respiratory Disease (BRD) Complex as a Signal for Bovine Viral Diarrhea Virus (BVDV) Presence in the Herd

Background: Infections are caused by Bovine Viral Diarrhea Virus and still continue to be a worldwide plague in cattle industry. It is responsible for sudden death syndromes in adult cattle with high mortality rates, abortions, acute gastrointestinal and respiratory diseases. The BVDV infection occurs in early pregnancy (40-142 days), in immunosuppressed females or cows results in 100% of persistently infected (PI) calves that are seronegative and asymptomatic at birth. Evidences suggests that BVDV contributes to BRD complex potentiating secondary infections caused by Mannheimia haemolytica e Pasteurella multocida due to its immunosuppressive action. However, the farmers have often associated the respiratory syndrome with other infectious agents. This paper reports the attendance of dairy calves manifesting clinical signs of bronchopneumonia, which led to the screening of the persistently infected animals to control of the BVDV infection in the herd.Materials, Methods & Results: During the technical assistance, ten calves manifesting bronchopneumonia were selected to trans-tracheal lavage (TL) in order to identify possible infectious agents. Reverse transcription polymerase chain reaction (RT-PCR) detected the presence of BVDV in two heifers. Pasteurella multocida was the unique bacterial agent isolated from TL (5/10, 50%). These data motivated the technical team and producers to investigate the PI screening by direct enzyme-linked immunosorbent assay from biopsies of the ear edge. The screening of PI’s detected 29 positive within of 2,342 animals tested (1.23%). The re-test of positive was performed only in 24 animals due to the cull of five bovine with severe bronchopneumonia and diarrhea, confirming 18 persistently infected calves (18/24; 75%). Finally, in all PI’s live dams were tested. It was observed four positive adult animals. One grand dam was live and tested, but it had negative result for direct enzyme-linked immunosorbent test. The rate of PI’s considering the whole herd was 0.81% (22/3,700 animals).Discussion: The involvement of BVDV in the etiology of bronchopneumonia was confirmed by detection of the virus in trans-tracheal lavages in two calves by RT-PCR. The susceptibility for Pasteurella multocida infection could be promoted by BVDV prime-infection, considering that immunossupressive nature of BVDV is a critical factor in the interaction with others viruses and bacteria. At this time, we are aware about any report about the detection of BVDV in trans-tracheal lavages. These findings culminated with the screening of PI animals in the herd, detecting rates of 0.81%. The intensive vaccination and colostrum management of this farm could protected the herd against BVDV, however others facts facilitated the introduction of the virus in the herd. This research was conduced in a high-production dairy farm with around 3,700 animals raised in an open herd, in which some of cows with high genetic potential were transferred for embryo collection in the state of Paraná, Brazil; resulting in the addition of the calves to the herd by others routes. Moreover, the farm used for many years vaccine containing only BVDV-1, which may have favored the entry and spread of BVDV-2 or BVDV-3 in the herd. This research showed the presence of BVDV in trans-tracheal lavage of heifers with bronchopneumonia by RT-PCR. This fact points to the need of BRD control programs that include detection of PI animals.

Cryptococcus gattii molecular type VGII infection associated with lung disease in a goat

Background

Cryptococcus gattii-induced cryptococcosis is an emerging infectious disease of humans and animals with worldwide distribution and public health importance due to its significant morbidity and mortality rate. The present study aimed to report a case of pulmonary infection by C. gattii molecular type VGII in State of São Paulo, Brazil.

Case presentation

A 5-year-old goat showing intermittent dry cough, ruminal tympany, anorexia, fever, tachycardia and tachypnea was presented for necropsy at the Veterinary Hospital of the School of Veterinary Medicine and Animal Sciences, São Paulo University, São Paulo, Brazil. Postmortem examination revealed numerous 2.0–6.0 cm diameter yellow gelatinous pulmonary masses. Tissues were evaluated by a combination of pathological, mycological, and molecular diagnostic techniques. Microscopically, pneumonia granulomatous, multifocal to coalescing, moderate, with many intralesional carminophilic yeasts was observed. The immunohistochemistry and mycological culture confirmed Cryptococcus spp. Internal transcribed spacers and orotidine monophosphate pyrophosphorylase nucleotide differentiation demonstrated that the isolate corresponds to the C. gattii VGII molecular subtype.

Conclusions

To our knowledge, this is the first report of a pulmonary infection in a goat linked to C. gattii molecular type VGII in Southeastern Brazil. Our findings emphasize the need for an active surveillance program for human and animal new infections to improve the current public health policies due to expansion of the epidemiological niche of this important microorganism.

Deletion of the gene encoding the islet-specific glucose-6-phosphatase catalytic subunit-related protein autoantigen results in a mild metabolic phenotype

AIMS/HYPOTHESIS

Islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP, now known as glucose-6-phosphatase, catalytic, 2 [G6PC2]) has recently been identified as a major autoantigen in mouse and human type 1 diabetes. Strategies designed to suppress expression of the gene encoding G6PC2 might therefore be useful in delaying or preventing the onset of this disease. However, since the function of G6PC2 is unclear, the concern with such an approach is that a change in G6PC2 expression might itself have deleterious consequences.

METHODS

To address this concern and assess the physiological function of G6PC2, we generated G6pc2-null mice and performed a phenotypic analysis focusing principally on energy metabolism.

RESULTS

No differences in body weight were observed and no gross anatomical or behavioural changes were evident. In 16-week-old animals, following a 6-h fast, a small but significant decrease in blood glucose was observed in both male (-14%) and female (-11%) G6pc2 (-/-) mice, while female G6pc2 (-/-) mice also exhibited a 12% decrease in plasma triacylglycerol. Plasma cholesterol, glycerol, insulin and glucagon concentrations were unchanged.

CONCLUSIONS/INTERPRETATION

These results argue against the possibility of G6PC2 playing a major role in pancreatic islet stimulus secretion coupling or energy homeostasis under physiological conditions imposed by conventional animal housing. This indicates that manipulating the expression of G6PC2 for therapeutic ends may be feasible.

Social functioning and facial emotional expression in neurological and psychiatric disorders

This study examined the relationship between facial expression and social functioning in schizophrenic, depressed, right-brain-damaged, Parkinson's disease, and normal adult participants. Raters evaluated general intensity and amount of positive and negative facial emotion while participants were producing monologues regarding pleasant and unpleasant experiences. Social functioning items were derived from three standardized inventories. Overall, patient groups displayed more negative and less positive emotion than normals, and the schizophrenic and right-brain-damaged groups showed less intense expressions than normals. Correlational analyses suggested that the more intense the facial expressions, the better the social functioning, and that the more negative emotion displayed, the poorer the social functioning.

Identification and characterization of a cDNA and the gene encoding the mouse ubiquitously expressed glucose-6-phosphatase catalytic subunit-related protein

Glucose-6-phosphatase (G6Pase) catalyzes the final step in the gluconeogenic and glycogenolytic pathways, the hydrolysis of glucose-6-phosphate (G6P) to glucose and phosphate. This paper describes the identification and characterization of a cDNA and the gene encoding the mouse ubiquitously expressed G6Pase catalytic subunit-related protein (UGRP). The open reading frame of this UGRP cDNA encodes a protein (346 amino acids (aa); Mr 38,755) that shares 36% overall identity (56% similarity) with the mouse G6Pase catalytic subunit (357 aa; Mr 40,454). UGRP exhibits a similar predicted transmembrane topology and conservation of many of the catalytically important residues with the G6Pase catalytic subunit; however, unlike the G6Pase catalytic subunit, UGRP does not catalyze G6P hydrolysis and does not contain a carboxy-terminal di-lysine endoplasmic reticulum retention signal. UGRP mRNA was detected by RNA blot analysis in every mouse tissue examined with the highest expression in heart, brain, testis and kidney. Database analysis showed that the mouse UGRP gene is composed of six exons, spans approximately 4.2 kbp of genomic DNA and is located on chromosome 11 along with the G6Pase catalytic subunit gene. The UGRP gene transcription start sites were mapped by primer extension analysis, and the activity of the mouse UGRP gene promoter was analyzed using luciferase fusion gene constructs. In contrast to the G6Pase catalytic subunit gene promoter, the UGRP promoter was highly active in all cell lines examined.

Identification and characterization of a human cDNA and gene encoding a ubiquitously expressed glucose-6-phosphatase catalytic subunit-related protein

Glucose-6-phosphatase (G6Pase) catalyzes the final step in the gluconeogenic and glycogenolytic pathways, the hydrolysis of glucose-6-phosphate (G6P) to glucose and phosphate. This paper describes the identification and characterization of a human cDNA and gene encoding a ubiquitously expressed G6Pase catalytic subunit-related protein (UGRP). The ORF of this UGRP cDNA encodes a protein (346 amino acids (aa); M(r) 38 709) which shares 36% overall identity to the human G6Pase catalytic subunit (357 aa; M(r) 40 487). UGRP exhibits a similar predicted transmembrane topology and conservation of many of the catalytically important residues with the G6Pase catalytic subunit; however, unlike the G6Pase catalytic subunit, UGRP does not catalyze G6P hydrolysis. UGRP mRNA was detected by RNA blot analysis in every tissue examined with the highest expression in muscle. Database analysis showed that the human UGRP gene is composed of six exons, spans approximately 5.4 kbp of genomic DNA and is located on chromosome 17q21 with the G6Pase catalytic subunit gene. The UGRP gene transcription start sites were mapped by primer extension analysis, and the activity of the UGRP gene promoter was analyzed using luciferase fusion gene constructs. In contrast to the G6Pase catalytic subunit gene promoter, the UGRP promoter was highly active in all cell lines examined.

Expression of the chaperonin 10 gene during zebrafish development

We have isolated a cDNA encoding chaperonin 10 (cpn10) from the zebrafish. Using northern, western, and in situ hybridization analysis, we observed that the cpn10 gene is expressed uniformly and ubiquitously throughout embryonic development of the zebrafish. Upregulation of cpn10 expression was observed following exposure of zebrafish embryos to a heat shock of 1 hour at 37 degrees C compared to control embryos raised at 27 degrees C. The extracellular form of Cpn10 called early pregnancy factor (EPF), found in the serum of pregnant mammals, was not detected in the serum of either male or female zebrafish. These expression studies suggest that Cpn10 plays a general role in zebrafish development as well as being consistent with the hypothesis that EPF is involved in the embryo implantation process in mammals.

[Exhumations procedures for investigating the genetic link in bones]

OBJECTIVE

To identify technical problems in exhumations performed for DNA detection in bones and to propose solutions through a protocol.

METHODS

A prospective and qualitative study of exhumations was carried out according to the methods proposed in the medical legal literature. From 1995 to 1998, were performed 10 exhumations to collect human remains for DNA extraction. Of them, seven cases were of civil interest and three of criminal. Alternatives were sought to overcome technical difficulties found during the execution of these procedures.

RESULTS

For all cases, there was scarcity of useful information to identify the human remains. In half of them, identification was based on the individual's morphological characteristics, given by their relatives. Individual morphological characteristics contributed to identification in 50% of cases. In three cases, it was possible to determine only the sex, and in one of them, only the age. Lack of infrastructure and police security in the cemeteries impaired the examination.

CONCLUSIONS

To assure the reliability of the DNA molecular examination, it is necessary to identify the individual to whom the exhumed mortal remains belonged. To an efficacious investigation, it is paramount to have a working protocol that will cover, among other issues, those concerning identification, infrastructure and staff safety at the site of examination.

Cloning and characterization of the human and rat islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) genes

Islet-specific glucose-6-phosphatase (G6Pase) catalytic subunit-related protein (IGRP) is a homolog of the catalytic subunit of G6Pase, the enzyme that catalyzes the terminal step of the gluconeogenic pathway. Its catalytic activity, however, has not been defined. Since IGRP gene expression is restricted to islets, this suggests a possible role in the regulation of islet metabolism and, hence, insulin secretion induced by metabolites. We report here a comparative analysis of the human, mouse, and rat IGRP genes. These studies aimed to identify conserved sequences that may be critical for IGRP function and that specify its restricted tissue distribution. The single copy human IGRP gene has five exons of similar length and coding sequence to the mouse IGRP gene and is located on human chromosome 2q28-32 adjacent to the myosin heavy chain 1B gene. In contrast, the rat IGRP gene does not appear to encode a protein as a result of a series of deletions and insertions in the coding sequence. Moreover, rat IGRP mRNA, unlike mouse and human IGRP mRNA, is not expressed in islets or islet-derived cell lines, an observation that was traced by fusion gene analysis to a mutation of the TATA box motif in the mouse/human IGRP promoters to TGTA in the rat sequence. The results provide a framework for the further analysis of the molecular basis for the tissue-restricted expression of the IGRP gene and the identification of key amino acid sequences that determine its biological activity.

A tool for comparison of PET and fMRI methods: calculation of the uncertainty in the location of an activation site in a PET image

A technique for calculating the uncertainty in the location of an activation site in a PET image, without performing repeated measures, is presented. With the development of new fMRI methods for measuring cerebral hemodynamics, demonstration of the efficacy of these techniques will be critical to establish clinical utility. Comparisons with PET are a powerful tool for validating these new fMRI techniques. In addition to the fact that PET techniques are well-established methods for making physiological measurements in vivo, PET methods are also free of the geometric distortions and nonuniform signal-to-noise artifacts (due to signal dropout) common in fMRI techniques. Comparisons reported previously have been limited by the large number of trials acquired in single-subject fMRI studies and the small number of trials in a PET study (due to the radiation dose to the patient or the interscan delays for tracer decay). Our method calculates both the center of mass (CM) of a predefined region of interest and the uncertainty in the location of the CM using the preimage PET data (sinograms). Results of phantom studies demonstrate that our method is an unbiased measurement equivalent to that of repeated measures with a large number of images. Extension of this technique to estimate the uncertainty in the location of an activation site in a PET statistical parametric map will permit precise rigorous comparisons of PET and fMRI methods in single subjects without the constraints imposed by the relatively small number of PET measurements.

Characterization of the mouse islet-specific glucose-6-phosphatase catalytic subunit-related protein gene promoter by in situ footprinting: correlation with fusion gene expression in the islet-derived betaTC-3 and hamster insulinoma tumor cell lines

Glucose-6-phosphatase (G6Pase) is a multicomponent system located in the endoplasmic reticulum comprising a catalytic subunit and transporters for glucose-6-phosphate, inorganic phosphate, and glucose. We have recently cloned a novel gene that encodes an islet-specific G6Pase catalytic subunit-related protein (IGRP) (Ebert et al., Diabetes 48:543-551, 1999). To begin to investigate the molecular basis for the islet-specific expression of the IGRP gene, a series of truncated IGRP-chloramphenicol acetyltransferase (CAT) fusion genes were transiently transfected into the islet-derived mouse betaTC-3 and hamster insulinoma tumor cell lines. In both cell lines, basal fusion gene expression decreased upon progressive deletion of the IGRP promoter sequence between -306 and -66, indicating that multiple promoter regions are required for maximal IGRP-CAT expression. The ligation-mediated polymerase chain reaction footprinting technique was then used to compare trans-acting factor binding to the IGRP promoter in situ in betaTC-3 cells, which express the endogenous IGRP gene, and adrenocortical Y1 cells, which do not. Multiple trans-acting factor binding sites were selectively identified in betaTC-3 cells that correlate with regions of the IGRP promoter identified as being required for basal IGRP-CAT fusion gene expression. The data suggest that hepatocyte nuclear factor 3 may be important for basal IGRP gene expression, as it is for glucagon, GLUT2, and Pdx-1 gene expression. In addition, binding sites for several trans-acting factors not previously associated with islet gene expression, as well as binding sites for potentially novel proteins, were identified.

Expression of the chaperonin 10 gene during zebrafish development

We have isolated a cDNA encoding chaperonin 10 (cpn10) from the zebrafish. Using northern, western, and in situ hybridization analysis, we observed that the cpn10 gene is expressed uniformly and ubiquitously throughout embryonic development of the zebrafish. Upregulation of cpn10 expression was observed following exposure of zebrafish embryos to a heat shock of 1 hour at 37 degrees C compared to control embryos raised at 27 degrees C. The extracellular form of Cpn10 called early pregnancy factor (EPF), found in the serum of pregnant mammals, was not detected in the serum of either male or female zebrafish. These expression studies suggest that Cpn10 plays a general role in zebrafish development as well as being consistent with the hypothesis that EPF is involved in the embryo implantation process in mammals.

Assessment of methods of homicides in a Brazilian city: a preliminary study

Homicides in the city of Ribeirão Preto, state of São Paulo, Brazil, were analyzed with regard to methods (firearms or others) and gender, in a retrospective study from 1993 to 1997. There was a progressive increase in the number of homicides, mainly after 1995, with an increment of 86.6% in 1997 in comparison to 1993. The incidence of homicides was higher among males, with firearms being the most common method in this group since 1993. In addition, a 10% increase in this method was observed since 1995, in association with a proportional reduction in the use of other methods. The incidence of homicides among females remained stable until 1996 and increased by 51.3% in 1997. Simultaneously, firearms have become the most common method among female victims (71.4%), pattern similar to that observed among males. Attention is drawn to the social and economic conditions and their relationships with drug traffic in the city.

Restricted expression of the zebrafish hsp90alpha gene in slow and fast muscle fiber lineages

Members of the heat shock protein 90 (Hsp90) family of molecular chaperones play important roles in allowing a select group of intracellular signaling molecules reach and maintain functionally active conformations. We have previously shown that hsp90alpha gene expression in early zebrafish embryos is restricted to a subgroup of paraxial-mesoderm derived somitic cells prior to muscle formation and that the gene is downregulated in mature trunk and tail muscle fibers. Here we have compared the expression of the hsp90alpha gene to muscle regulatory genes during development of slow and fast muscle fibers in normal embryos and in embryos carrying mutations which affect somitic muscle formation. We show that hsp90alpha is first expressed early during the development of slow somitic muscle progenitors shortly following myoD activation and at a point prior to or co-incident with the expression of other known muscle regulatory genes. Expression of hsp90alpha is also activated in the midline of flh mutants when these cells switch from a notochord to a muscle fate. Conversely, expression is not detectable in cells of the paraxial mesoderm lineage which fail to converge in spt mutants and which do not activate expression of other muscle specific marker genes. Finally, expression of hsp90alpha is downregulated in slow muscle fibers by 24 h of age but becomes detectable in the later developing fast fibers at this time. Thus, hsp90alpha is expressed in developing muscle progenitors during short temporal and spatial windows of both slow and fast fiber lineages in the zebrafish somite.

Disruption of zebrafish somite development by pharmacologic inhibition of Hsp90

Members of the Hsp90 family of molecular chaperones play important roles in allowing some intracellular signaling molecules and transcription factors to reach and maintain functionally active conformations. In the present study, we have utilized the specific Hsp90-binding agent, geldanamycin, to examine the requirement for Hsp90 during zebrafish development. We show that geldanamycin interacts with both the alpha and the beta-isoforms of zebrafish Hsp90 and that geldanamycin-treated embryos consistently exhibit a number of defects in tissues which express either one of these genes. Within the somites, geldanamycin treatment results in the absence of eng-2-expressing muscle pioneer cells. However, early development of adaxial cells, which give rise to muscle pioneers and which strongly express the hsp90alpha gene shortly before muscle pioneer formation, appeared unaffected. Furthermore, development of the notochord, which provides many of the signals required for proper somite patterning and which does not express detectable levels of either hsp90alpha or hsp90beta mRNA, was similarly unaffected in geldanamycin-treated embryos. The data are consistent with there being a temporal and spatial requirement for Hsp90 function within somitic cells which is necessary for the formation of eng-2-expressing muscle pioneers and possibly other striated muscle fiber types.

Reciprocal limbic-cortical function and negative mood: converging PET findings in depression and normal sadness

OBJECTIVE

Theories of human behavior from Plato to Freud have repeatedly emphasized links between emotion and reason, a relationship now commonly attributed to pathways connecting phylogenetically "old" and "new" brain regions. Expanding on this theory, this study examined functional interactions between specific limbic and neocortical regions accompanying normal and disease-associated shifts in negative mood state.

METHOD

Regions of concordant functional change accompanying provocation of transient sadness in healthy volunteers and resolution of chronic dysphoric symptoms in depressed patients were examined with two positron emission tomography techniques: [15O]water and [18F]fluorodeoxyglucose, respectively.

RESULTS

With sadness, increases in limbic-paralimbic blood flow (subgenual cingulate, anterior insula) and decreases in neocortical regions (right dorsolateral prefrontal, inferior parietal) were identified. With recovery from depression, the reverse pattern, involving the same regions, was seen--limbic metabolic decreases and neocortical increases. A significant inverse correlation between subgenual cingulate and right dorsolateral prefrontal activity was also demonstrated in both conditions.

CONCLUSIONS

Reciprocal changes involving subgenual cingulate and right prefrontal cortex occur with both transient and chronic changes in negative mood. The presence and maintenance of functional reciprocity between these regions with shifts in mood in either direction suggests that these regional interactions are obligatory and probably mediate the well-recognized relationships between mood and attention seen in both normal and pathological conditions. The bidirectional nature of this limbic-cortical reciprocity provides additional evidence of potential mechanisms mediating cognitive ("top-down"), pharmacological (mixed), and surgical ("bottom-up") treatments of mood disorders such as depression.

A role for DNA methylation in gastrulation and somite patterning

DNA methylation constitutes an important epigenetic factor in the control of genetic information. In this study, we analyzed expression of the DNA methyltransferase gene and examined DNA methylation patterns during early development of the zebrafish. Maternal transcripts of the zebrafish DNA methyltransferase gene (MTase) are ubiquitously present at high levels in early embryos with overall levels decreasing after the blastula stage. At 24 h, methyltransferase mRNA is predominantly found in the brain, neural tube, eyes, and differentiating somites. Expression of MTase in the somites is highest in the anterior cells of the somites. Despite the high levels of MTase mRNA in blastula-stage embryos, we observe DNA hypomethylation at the blastula and gastrula stages compared to sperm or older embryos. Zebrafish embryos treated with 5-azacytidine (5-azaC) and 5-aza-2-deoxycytidine (5-azadC), nucleotide analogs known to induce cellular differentiation and DNA hypomethylation in mammalian cells, exhibit DNA hypomethylation and developmental perturbations. These defects are specifically observed in embryos treated at the beginning of the blastula period, just prior to midblastula transition. The most common phenotype is the loss of tail and abnormal patterning of somites. Head development is also affected in some embryos. Histological and in situ hybridization analyses reveal whole or partial loss of a differentiated notochord and midline muscle in treated embryos. When examined during gastrulation, 5-azaC-treated embryos have a shortened and thickened axial mesoderm. We propose that DNA methylation is required for normal gastrulation and subsequent patterning of the dorsal mesoderm.

Effect of partition coefficient, permeability surface product, and radioisotope on the signal-to-noise ratio in PET functional brain mapping: a computer simulation

In this work we use a computer simulation to estimate the magnitude of improvement in the signal-to-noise ratio of PET functional brain mapping studies as a function of partition coefficient and permeability surface product for O-14, F-17, and O-15 labeled flow tracers. A model for signal-to-noise ratio is derived from the Kety model for inert diffusible blood flow tracers. The results of the simulation suggest that moderate increases in partition coefficient and permeability surface product compared with water would lead to an increase in signal-to-noise ratio of a factor of about 3.

DNA methylation and genome imprinting in the zebrafish, Danio rerio: some evolutionary ramifications

Although methylation has been recognized as an important component in a number of developmental processes in mammals, in zebrafish almost nothing is known about this epigenetic modification. This is despite the fact that the zebrafish is becoming increasingly popular as a developmental model system. The little work that has been done on methylation and development in fish concerns genomic imprinting. In mammals, imprinting results in an inability to reproduce parthenogenetically because a genetic contribution from both parents is necessary to successfully complete development. However, this is not true of zebrafish, and a number of the theories that have been presented to explain the evolution of imprinting are not consistent with imprinting in these fish. A new model is presented that discusses some of the potential evolutionary ramifications of methylation and imprinting and that leads to the suggestion that imprinting may actually be a simple genetic mechanism to enhance the efficient evolution of both individual genetic loci and combinations of loci with related functions, without risking the population as a whole. This model can accommodate all of the information known about imprinting, including its broad phylogenetic range, imprinting by both males and females, and the diverse nature of the genes that are known to be imprinted.

Teaching cardiology auscultation. A wireless FM broadcast system

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DNA methylation and genome imprinting in the zebrafish, Danio rerio: some evolutionary ramifications

Although methylation has been recognized as an important component in a number of developmental processes in mammals, in zebrafish almost nothing is known about this epigenetic modification. This is despite the fact that the zebrafish is becoming increasingly popular as a developmental model system. The little work that has been done on methylation and development in fish concerns genomic imprinting. In mammals, imprinting results in an inability to reproduce parthenogenetically because a genetic contribution from both parents is necessary to successfully complete development. However, this is not true of zebrafish, and a number of the theories that have been presented to explain the evolution of imprinting are not consistent with imprinting in these fish. A new model is presented that discusses some of the potential evolutionary ramifications of methylation and imprinting and that leads to the suggestion that imprinting may actually be a simple genetic mechanism to enhance the efficient evolution of both individual genetic loci and combinations of loci with related functions, without risking the population as a whole. This model can accommodate all of the information known about imprinting, including its broad phylogenetic range, imprinting by both males and females, and the diverse nature of the genes that are known to be imprinted.

The pharmacokinetics of hyperpolarized xenon: implications for cerebral MRI

In this work, a compartmental model to predict the concentration of hyperpolarized xenon (Xe) in the brain is developed based on the well established kinetics of Xe and estimated T1 values for the compartments. For the gaseous compartments, T1 was set to 12 seconds. For the tissue compartments, T1 was set to 6 seconds. Three gas delivery techniques were modeled: hyperventilation followed by breath-hold, continual breathing, and hyperventilation followed by continual breathing. Based on Xe CT, it is estimated that the maximum concentration of Xe that could be breathed is 80%. Based on this value and the estimated maximum polarization of 50%, the peak gray matter concentration of hyperpolarized Xe is calculated to be .036 mM. This leads to an estimated signal-to-noise ratio (SNR), at 2 T, for hyperpolarized Xe that is a factor of 50 lower than the SNR for proton MRI. The peak concentration of hyperpolarized Xe was also calculated over a wide range of gas and tissue T1 values. This model also predicts that the arterial blood will have a concentration of hyperpolarized Xe that is 10 times greater than the concentration in gray matter. An interactive version of the model can be found on the World Wide Web at http:(/)/ric.uthscsa.edu/staff /charlesmartinphd.html.

Xenon effects on regional cerebral blood flow assessed by 15O-H2O positron emission tomography: implications for hyperpolarized xenon MRI

Subjective and physiologic effects of 33% inhaled Xe were measured with 15O-water positron emission tomography (PET) in 3 subjects at rest and during visual stimulation. The procedure was well tolerated. Robust functional activations of the visual cortex were obtained after xenon (Xe) inhalation as well as air breathing. However, Xe inhalation was followed by smaller size, but significant decreases of regional cerebral blood flow (rCBF) in visual cortex relative to the air-breathing baseline, both during visual stimulation and at rest. No such decreases were found in other sensory or motor regions.

Cingulate function in depression: a potential predictor of treatment response

The relationship between pretreatment regional cerebral glucose metabolism and eventual antidepressant drug response was measured using positron emission tomography (PET) in hospitalized patients with unipolar depression. Rostral anterior cingulate metabolism uniquely differentiated eventual treatment responders from non-responders. Hypometabolism characterized non-responders when compared with controls, in contrast to responders who were hypermetabolic. Metabolism in no other region discriminated the two groups, nor did associated demographic, clinical or behavioral measures, including motor speed, cognitive performance, depression severity or illness chronicity. Cingulate hypermetabolism may represent an important adaptive response to depression and failure of this response may underlie poor outcome. A critical role for rostral cingulate area 24a/b in the limbic-cortical network involved in abnormal mood states is proposed.

Specific craniofacial cartilage dysmorphogenesis coincides with a loss of dlx gene expression in retinoic acid-treated zebrafish embryos

Treatments of zebrafish embryos with retinoic acid (RA), a substance known to cause abnormal craniofacial cartilage development in other vertebrates, result in dose- and stage-dependent losses of dlx homeobox gene expression in several regions of the embryo. Dlx expression in neural crest cells migrating from the hindbrain and in the visceral arch primordia is particularly sensitive to RA treatment. The strongest effects are observed when RA is administered prior to or during crest cell migration but effects can also be observed if RA is applied when the cells have entered the primordia of the arches. Losses of dlx expression correlate either with the loss of cartilage elements originating from hindbrain neural crest cells or with abnormal morphology of these elements. Cartilage elements that originate from midbrain neural crest cells, which do not express dlx genes, are less affected. Taken together with the observation that the normal patterns of visceral arch dlx expression just prior to cartilage condensation resemble the morphology of the cartilage elements that are about to differentiate, our results suggest that dlx genes are an important part of a multi-step process in the development of a subset of craniofacial cartilage elements.

Stable transfer of zebrafish chromosome segments into mouse cells

Whole-cell fusion between zebrafish fibroblast-like ZF4 cells and mouse B78 melanoma cells resulted in hybrids containing one or a few zebrafish chromosome segments in a murine chromosomal background. Fluorescence in situ hybridization to hybrid cell metaphases with a zebrafish genomic DNA probe revealed that many hybrids contained zebrafish chromosome segments that were either inserted or translocated to a mouse chromosome, whereas other hybrids contained zebrafish chromosomes with no evidence of insertion or translocation. We have assigned hybrids to 17 linkage groups of the genetic map of the zebrafish genome. Our results demonstrate the feasibility of producing somatic cell hybrids between distantly related species. Zebrafish/mouse cell hybrids will provide a useful tool for the physical mapping of the zebrafish genome and for the cloning of genes affected in zebrafish mutants.

Weed control in tropical ley farming systems: a review

The first sustained effort to develop a ley farming system (a pasture legume rotated with a grain crop) for the Australian semi-arid tropics began in the late 1970s at Katherine, Northern Territory, where various strategies were identified and implemented. It was soon discovered that a main constraint to success was the invasion of the legume ley by grass weeds. This occurred despite the replacement of Townsville stylo (Stylosanthes humilis), which provided the base for the early work, with more competitive legumes such as Verano (Stylosanthes hamata) and Centurion centro (Centrosema pascuorum). Early weed control work focused on the use of chemicals, but later competition and population dynamics were studied in S. humilis pastures. The ley farming system comprised a number of essential elements, each of which offered opportunities for weed control First, a legume ley was rotated with grain crops. Past work concentrated on legume leys, but nitrogen (N)-fertilised grass leys may be successful if the N was economically supplied. Grasses can effectively suppress weeds. Rotation of herbicides is possible. Sicklepod (Senna obtusifolia) can be controlled with atrazine in the sorghum phase, and emergent Sida spp. can be controlled in the pasture phase using a herbicide roller. Second, cattle graze the legume ley and crop residues in the dry season. Cattle can be used to suppress grass weeds in the wet season. The major use of the legume ley, however, was to provide high quality food in the dry season when there was little other available food. Future research should investigate the economics of balancing the need for grass weed control with food provision in the dry season. Third, crops sown directly into a ley killed with a knockdown herbicide. Although the need for improved soil surface management was recognised early, development of reduced tillage was delayed until the availability of glyphosate. Initial work concentrated on improving plant establishment under mulch. Recent work has shown that mulches can effectively control weeds in crops without the use of herbicides; best weed control occurred when glyphosate was applied as a single application at sowing. Fourth, ley regenerated as an intercrop in the grain crop. There is no doubt that the presence of an intercrop reduces the yield of the grain crop. Future research should investigate the economics and risks associated with intercrop-induced changes in yield and herbicide use patterns. The extreme climate and sandy soils pose problems for herbicide use. There is marked seasonal variation in effectiveness of pre-emergence herbicides, ranging from zero to marked crop phytotoxicity. The effectiveness of knockdown herbicides is reduced by stressed target plants and rain soon after spraying. Mulch dynamics, grazing, competition and interference, and herbicide interactions with target plants and the environment, were identified as key features requiring attention in a ley farming system to achieve practical weed management.

Use of implicit motor imagery for visual shape discrimination as revealed by PET

Positron emission tomography (PET) can be used to map brain regions that are active when a visual object (for example, a hand) is discriminated from its mirror form. Chronometric studies suggest that viewers 'solve' this visual shape task by mentally modelling it as a reaching task, implicitly moving their left hand into the orientation of any left-hand stimulus (and conversely for a right-hand stimulus). Here we describe an experiment in which visual and somatic processing are dissociated by presenting right hands to the left visual field and vice versa. Frontal (motor), parietal (somatosensory) and cerebellar (sensorimotor) regions similar to those activated by actual and imagined movement are strongly activated, whereas primary somatosensory and motor cortices are not. We conclude that mental imagery is realized at intermediate-to-high order, modality-specific cortical systems, but does not require primary cortex and is not constrained to the perceptual systems of the presented stimuli.

Genotype-specific modifiers of transgene methylation and expression in the zebrafish, Danio rerio

Previous reports involving mammalian systems, particularly mice, have demonstrated the existence of cis- and trans-acting modifiers of transgene methylation. These modifiers are thought to be important in dominance modification, genome imprinting and cellular expression mosaicism. Their potential role in the penetrance and severity of many complex human diseases could be of even greater significance. In the present investigation we demonstrate that modifiers that act in a similar fashion to those identified in mice also exist in a non-mammalian vertebrate, the zebrafish Danio rerio. We also provide evidence that the transgene methylation pattern may be influenced by the sex of the individual and environmental modulators such as temperature and sodium butyrate. These data support the theory that this type of dominance modification is mechanistically similar to position effect variegation in Drosophila. Furthermore, these data suggest evolutionary conservation of the modifiers, at least within vertebrates, and imply that they and their actions are important in normal vertebrate development.

Quantitative PET with positron emitters that emit prompt gamma rays

The purpose of this work was to determine the feasibility of using positron emitting isotopes that emit prompt gammas to acquire quantitative positron emission tomography (PET) data using standard PET instrumentation. Prompt gammas can contaminate PET data by increasing dead time, converting singles into invalid coincidences, and producing multiple coincidences which can lead to the replacement of valid coincidences by invalid coincidences. The measurements in this work were made by scanning point sources containing F-18, Na-22, and Co-60 and studying the effects of the prompt gammas on the PET data, We found that for the Na-22 point source, the annihilation photon coincidence rate was about 25 times the prompt gamma-annihilation photon coincidence rate in the entire active volume of the scanner. With scatter, the Na-22 prompt gamma-annihilation photon coincidence rate was 1.3 times higher than the F-18 scatter coincidence rate. The most significant effect of the prompt gamma was to increase dead time; the dead time correction factor for Cu-60 was 2.4 times higher than the correction factor for N-13 for the same source activity. We conclude that, in many cases, quantitative PET data can be readily obtained with isotopes that emit prompt gammas, using standard PET 2-D instrumentation. However there are some cases, such as 3-D PET, where prompt gammas could significantly contaminate the PET data.

Synthesis of the fluorine-18 labeled inhalation anesthetics

Fourteen compounds (fluoroalkanes and fluoroethers), including the two most utilized inhalation anesthetics Isoflurane (CF3CHClOCF2H) and Halothane (CF3CHBrCl), have been labeled with fluorine-18 via a facile 18F-for-19F exchange reaction. The compounds include ten inhalation anesthetics which span a ten-fold range in potency and four structurally related non-anesthetics. All the compounds possess a trifluoromethyl group (CF3) adjoining a carbon atom with an acidic alpha-hydrogen and at least one halogen or a strong electron withdrawing group (X), [CF3CHXR]. We postulate the isotopic fluoride exchange reaction proceeds through a carbanion transition state resulting from alpha-proton transfer to base. The carbanion stability is attributed to the inductive effect of the CF3 group and the electron withdrawing capability of X. Compounds labeled in dimethyl sulfoxide (DMSO) at 125 degrees C in 15 min include Isoflurane-CF3CHClOCF2H (1) (97% [18F]fluorine incorporation, 99% radiochemical purity, respectively), Sevoflurane-CF3CHCF3OCFH2 (2) [98%, 99%], CF3CHBrOCF2H (3) [85%, 80%], Desflurane-CF3CHFOCF2H (4) [50%, 99%], Fluroxene-CF3CH2OCH = CH2 (5) [25%, 99%], Fluothyl-CF3CH2OCH2CF3 (6) [60%, 10% at a temperature of 175 degrees C], Halothane-CF3CHBrCl (7) [98%, 95%], CF3CH2I (8) [99%, 98%], CF3CH2Br (9) [18%, 98%], CF3CHCl2 (10) [95%, 98%], CF3CH2Cl (11) [90%, 20%], CF3CHClCF3 (12) [95%, 99%], (CF3)3CH (13) [99%, 99%] and HF-134a-CF3CFH2 (14) (15%, 93% at a temperature of 175 degrees C).

Furrowing surface contraction wave coincident with primary neural induction in amphibian embryos

We predicted, and have now observed, a surface contraction wave in axolotl (Ambystoma mexicanum) embryos that appears to coincide temporally and spatially with primary neural induction and homoiogenetic induction, and with involution of the chordomesoderm. The wave starts from a focus anterior to the dorsal lip of the blastopore and spreads as an ellipse, until part of it encounters the rim of the blastopore and vanishes there. The remaining arc then continues over the dorsal hemisphere until it reforms an ellipse that decreases in size. About 9 to 12 hours after it begins, the wave vanishes at a focus diametrically opposite its point of origin. The wave involves both local contraction and furrowing in the monolayer ectoderm. To a good approximation, the hemispherical portion of the ectoderm traversed by the wave becomes neuroepithelium, while the ectoderm not traversed by the wave becomes epidermis. The wave might provide a mechanism to determine the time and location at which neuroepithelial differentiation occurs.

Perception of facial emotion in schizophrenic and right brain-damaged patients

Deficits in the perception of facial emotion have been demonstrated in patients with right-sided brain damage (RBD) and schizophrenia (SZ). Furthermore, recent speculations have implicated right-hemisphere dysfunction in Type II schizophrenics, especially those with a preponderance of "negative symptoms" and flat affect. The performance of SZ, RBD, and normal control subjects was compared on measures assessing facial emotional perception. Both identification and discrimination paradigms were used, with positive/pleasant and negative/unpleasant emotions. To examine the effects of visuospatial and facial processing on facial emotion tasks, the Visual Matrices Test and the Benton Facial Recognition Test were administered. On both facial emotion tests, SZ and RBD patients were significantly impaired relative to normal subjects, but not different from each other. The SZ and RBD patients were also impaired on the matrices and facial recognition tests. When the effects of the matrices and neutral face recognition tests were statistically controlled, significant group differences remained for the identification task but not for the discrimination task. Thus, methodologies are presented for the neuropsychological study of facial emotional perception, and some support is provided for the notion that negative-symptom schizophrenia is associated with right hemisphere dysfunction.

Agronomic studies on the productivity of kenaf (Hibiscus cannabinus L. cv. Guatemala 4) under rainfed and irrigated conditions in the Northern Territory

Field experiments were conducted at Berrimah, Douglas Daly and Katherine in the Northern Territory (NT) during the 1987-88 and 1988-89 wet seasons to obtain yield data for kenaf (Hibiscus cannabinzis L. cv. Guatemala 4) grown under rainfed and irrigated conditions. Under rainfed conditions, maximum stem yield was obtained from sowings early in the wet season. Yield decreased with delay in sowing until the late-December-January period. The maximum rainfed stem yield at Katherine in an above-average rainfall season was 18 400 kg/ha. The maximum yield in a below average rainfall season was 11 700 kg/ha at Katherine, 9200 kg/ha at Douglas Daly and 9400 kg/ha at Berrimah. The applicability to the NT of growth and yield relationships established for irrigated kenaf in the Ord Irrigation Area (OIA) was assessed. The yield potential under irrigated conditions in the NT (21 600 kg/ha at 131 days after sowing) was higher than that reported elsewhere in Australia for the same growth period, but similar to that reported elsewhere for longer growth duration (180-300 days). In the NT, in contrast to the OIA, stem yield showed little or no response to N fertilisation. Stem yield was not related to N uptake, and at high levels of N application, there was marked N accumulation in the stem. Kenaf was able to accumulate up to 110 kg N/ha from the soil reserve where no N was applied. The yield response to plant density varied with the yield level and was similar to that in the OIA. Bark and core yield could be estimated directly from biomass, and indirectly from stem length and plant density, over a wide range of yield levels and cultural conditions. It was concluded that data relating to yield potential and response to N fertilisation cannot be transferred directly from the OIA to the NT.

Advances in electronic reproduction of the clinical bedside examination for cardiovascular education

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Cassette videotape recording of computer images

Direct videotape recording of images from computer display terminals is often not possible because of the nonstandard outputs of these systems. A video-sync mixer is described that permits black-and-white recording on standard 3/4-in. videotape cassettes.