Biomedical subjects

J F Smith

Publications and source records attributed to J F Smith.

At least 55 records · Page 3Linked to original sources

PubMed1998

Association of Venezuelan equine encephalitis virus subtype IE with two equine epizootics in Mexico.

Two outbreaks of encephalitis consistent with an etiology of Venezuelan equine encephalitis (VEE) virus occurred in equines on the Pacific coast of southern Mexico in 1993 (Chiapas State) and in 1996 (Oaxaca State). In Chiapas, there were 125 cases, of which 63 were fatal and in Oaxaca, there were 32 cases and 12 fatalities. Virus was isolated from two horses from each outbreak, including three brain isolates and one from blood. Virus isolates (93-42124, ISET-Chi93, Oax131, and Oax142) were shown by indirect immunofluorescence, hemagglutination inhibition, monoclonal antibody ELISA, and nucleotide sequencing to be VEE virus, subtype IE, a type previously thought to be equine-avirulent. Genetic characterization and phylogenetic analysis indicated that the outbreak viruses were identical or nearly identical to one another and that they were closely related to equine-avirulent IE strains from Guatemala and the Gulf coast of Mexico. In a plaque-reduction neutralization test, sera collected from healthy horses in Chiapas and Oaxaca reacted significantly better with isolate 93-42124 than with Guatemala IE isolate 68U201, suggesting that subtle genetic changes may have resulted in alteration of neutralization domains. It is not clear whether these differences may also influence equine virulence. However, renewed VEE virus subtype IE activity in Mexico, and its apparent conversion to equine virulence, underscores the need for increased surveillance, additional laboratory and epidemiologic studies in VEE-endemic regions, and possibly new vaccines.

Amino Acid Sequence↗

PubMed1998

Describing pain management documentation.

Managing postsurgical pain continues to be one of the nation's top clinical care priorities and concerns. Despite widely publicized national care guidelines, effective pain management for all patients is not a reality. This study explored how nurses in a community hospital documented the process of pain management for a group of postsurgical patients. The results have implications for all adult health nurses.

Adolescent↗

PubMed1998

A simple model for learning stereotactic skills in ultrasound-guided amniocentesis.

BACKGROUND: Amniocentesis is an important procedure for antenatal diagnosis but requires stereotactic skill acquisition that may be facilitated by the use of a model. TECHNIQUE: A model using a gelatin mold with "targets" within is created. The model is used to facilitate development of stereotactic skills and to demonstrate technique principles for ultrasound-guided amniocentesis. EXPERIENCE: The model has been incorporated into an educational program for antenatal diagnosis within a residency and provides a reasonable simulation of clinical features important in learning genetic amniocentesis. CONCLUSION: The use of this model augments the learning of important skills needed for ultrasound-guided amniocentesis.

Amniocentesis↗

PubMed1997

Replicon-helper systems from attenuated Venezuelan equine encephalitis virus: expression of heterologous genes in vitro and immunization against heterologous pathogens in vivo.

A replicon vaccine vector system was developed from an attenuated strain of Venezuelan equine encephalitis virus (VEE). The replicon RNA consists of the cis-acting 5' and 3' ends of the VEE genome, the complete nonstructural protein gene region, and the subgenomic 26S promoter. The genes encoding the VEE structural proteins were replaced with the influenza virus hemagglutinin (HA) or the Lassa virus nucleocapsid (N) gene, and upon transfection into eukaryotic cells by electroporation, these replicon RNAs directed the efficient, high-level synthesis of the HA or N proteins. For packaging of replicon RNAs into VEE replicon particles (VRP), the VEE capsid and glycoproteins were supplied in trans by expression from helper RNA(s) coelectroporated with the replicon. A number of different helper constructs, expressing the VEE structural proteins from a single or two separate helper RNAs, were derived from attenuated VEE strains Regeneration of infectious virus was not detected when replicons were packaged using a bipartite helper system encoding the VEE capsid protein and glycoproteins on two separate RNAs. Subcutaneous immunization of BALB/c mice with VRP expressing the influenza HA or Lassa virus N gene (HA-VRP or N-VRP, respectively) induced antibody responses to the expressed protein. After two inoculations of HA-VRP, complete protection against intranasal challenge with influenza was observed. Furthermore, sequential immunization of mice with two inoculations of N-VRP prior to two inoculations of HA-VRP induced an immune response to both HA and N equivalent to immunization with either VRP construct alone. Protection against influenza challenge was unaffected by previous N-VRP immunization. Therefore, the VEE replicon system was characterized by high-level expression of heterologous genes in cultured cells, little or no regeneration of plaque-forming virus particles, the capability for sequential immunization to multiple pathogens in the same host, and induction of protective immunity against a mucosal pathogen.

Animals↗

PubMed1997

Identification of a STAT6 domain required for IL-4-induced activation of transcription.

Tyrosine phosphorylation of STAT6 in response to IL-4 results in the formation of STAT6 homodimers that bind specific DNA elements. Although binding sites for STAT6 have been shown to be important for the function of several IL-4-inducible promoters, the role of STAT6 in this activation has not been defined. To determine whether STAT6 is a transcriptional activator, different portions of the carboxyl terminus of STAT6 were fused to the yeast Gal4 protein DNA binding domain. Analysis of these chimeric Gal4-STAT6 proteins demonstrates that a 140-amino-acid proline-rich region of the carboxyl terminus of STAT6 contains a region that activates transcription. Truncation mutants of STAT6 that lack this domain cannot activate transcription and are capable of repressing transcription stimulated by a wild-type STAT6 protein. Strikingly, the ability of IL-4 to induce transcription from the Ig germline epsilon promoter is suppressed by overexpression of a carboxyl-terminal deletion mutant of STAT6. These studies demonstrate that the carboxyl terminus of STAT6 contains an activating domain required for the induction of genes by IL-4.

Amino Acid Sequence↗

PubMed1997

Doppler evidence of improved fetoplacental hemodynamics following amnioreduction in the stuck twin phenomenon.

BACKGROUND: Doppler ultrasound of the umbilical cord has been used to assess stuck twin pregnancies, with variable results. We describe a case of immediate improvement in the umbilical artery velocimetry of a stuck twin following amnioreduction. CASE: Pregnancy complicated by the stuck twin phenomenon was managed by serial amnioreductions. Initial improvement was followed by progressive evidence of hydrops in the smaller, stuck twin. Absent diastolic flow was corrected immediately by further amnioreduction; subsequently the evidence of hydrops resolved. CONCLUSION: Amnioreduction may be associated with a measurable improvement in fetoplacental hemodynamics in the stuck twin phenomenon as assessed by Doppler ultrasound.

Adult↗

PubMed1997

Fetal laceration injury at cesarean delivery.

OBJECTIVE: To investigate the incidence of fetal laceration injury in cesarean delivery. METHODS: A retrospective review was conducted using a computer-based data coding system. All neonatal records were reviewed for infants delivered by cesarean during a 2-year period. Maternal records were reviewed in those cases of documented fetal laceration injury. The Fisher exact test was used when indicated. RESULTS: There were 904 cesarean deliveries performed during the study period; of these, 896 neonatal records (98.4%) were available for review. Seventeen laceration injuries were recorded (1.9%). The incidence of laceration appeared higher when the indication for cesarean was nonvertex (6.0% versus 1.4%, P = .02). One of 17 (5.9%) maternal records indicated the presence of the laceration of the fetus. CONCLUSION: Fetal laceration injury at cesarean delivery is not rare, especially when it is performed for nonvertex presentation. The minority of obstetric records show documentation of such lacerations, suggesting that this complication often may not be recognized by obstetricians.

Cesarean Section↗

PubMed1997

Motility of ram spermatozoa during storage in a chemically-defined diluent containing antioxidants.

The effects of five antioxidants--Vitamin E (VE), butylated hydroxyanisole (BHA), n-propyl gallate (n-PG), deferoxamine mesylate (Desferal) and catalase (EC 1 . 11 . 1 . 6)--on the maintenance of motility of ram spermatozoa in a chemically-defined ram semen diluent (RSD-1) have been evaluated. VE, n-PG and Desferal inhibited spermatozoal motility. The relative inhibition (i.e., ratio of change in % motility over 24 h between the treatment group and the corresponding control) at equimolar concentrations (100 microM) of Desferal, VE and n-PG were 1.6, 1.8 and 3.6 respectively. BHA had no effect at 10 microM but at lower concentrations, gave a slight improvement in motility in freshly diluted spermatozoal samples and in those stored for 1 day at 15 degrees C. The addition of catalase to RSD-1 was also ineffective in improving the motility of spermatozoa. The lack of beneficial effects of the tested antioxidants suggests that RSD-1 itself may destroy reactive oxygen species and the antioxidant activity of RSD-1 components requires further study.

Animals↗

PubMed1997

Repeated emergence of epidemic/epizootic Venezuelan equine encephalitis from a single genotype of enzootic subtype ID virus.

Venezuelan equine encephalitis (VEE) epidemics and equine epizootics occurred periodically in the Americas from the 1920s until the early 1970s, when the causative viruses, subtypes IAB and IC, were postulated to have become extinct. Recent outbreaks in Columbia and Venezuela have renewed interest in the source of epidemic/epizootic viruses and their mechanism of interepizootic maintenance. We performed phylogenetic analyses of VEE virus isolates spanning the entire temporal and geographic range of strains available, using 857-nucleotide reverse transcription-PCR products including the E3 and E2 genes. Analyses indicated that epidemic/epizootic viruses are closely related to four distinct, enzootic subtype ID-like lineages. One of these lineages, which occurs in Columbia, Peru, and Venezuela, also included all of the epidemic/epizootic isolates; the remaining three ID-like lineages, which occur in Panama, Peru, Florida, coastal Ecuador, and southwestern Columbia, were apparently not associated with epizootic VEE emergence. Within the Columbia/Peru/Venezuela lineage, three distinct monophyletic groups of epidemic/epizootic viruses were delineated, indicating that VEE emergence has occurred independently at least three times (convergent evolution). Representative, complete E2 amino acid sequences were compared to identify potential determinants of equine virulence and epizootic emergence. Amino acids implicated previously in laboratory mouse attenuation generally did not vary among the natural isolates that we examined, indicating that they probably are not involved in equine virulence changes associated with VEE emergence. Most informative amino acids correlated with phylogenetic relationships rather than phenotypic characteristics, suggesting that VEE emergence has resulted from several distinct combinations of mutations that generate viruses with similar antigenic and equine virulence phenotypes.

Amino Acid Sequence↗

PubMed1997

Primary cell culture of human type II pneumonocytes: maintenance of a differentiated phenotype and transfection with recombinant adenoviruses.

Studies of the regulation of surfactant lipoprotein metabolism and secretion and surfactant protein gene expression have been hampered by the lack of a cell culture system in which the phenotypic properties of type II cells are maintained. We have developed a primary culture system that facilitates the maintenance of a number of morphologic and biochemical properties of type II pneumonocytes for up to 2 wk. Cells were isolated by collagenase digestion of midgestation human fetal lung tissue that had been maintained in organ culture in the presence of dibutyryl cyclic AMP (Bt2cAMP) for 5 days. The isolated cells were enriched for epithelial components by treatment with DEAE-dextran, plated on an extracellular matrix (ECM) derived from Madin-Darby canine kidney (MDCK) cells, and incubated at an air/liquid interface in a minimal amount of culture medium containing Bt2cAMP. The cell cultures were comprised of islands of round epithelial-like cells containing numerous dense osmiophilic granules, surrounded by sparse spindle-shaped cells with the appearance of fibroblasts. Ultrastructural examination revealed that the osmiophilic granules had the appearance of lamellar bodies, the distinguishing feature of type II pneumonocytes. Additionally, the cultures maintained elevated levels of SP-A gene expression for up to 2 wk. The expression of mRNAs encoding SP-A, SP-B, and SP-C were regulated in the cultured cells by glucocorticoids and cyclic AMP in a manner similar to that observed in fetal lung tissue in organ culture. The differentiated phenotype was most apparent when the cells were cultured at an air/liquid interface. In order to utilize the cultured type II cells for study of the effects of overexpression of various proteins and for promoter analysis, it is of essence to transfect DNA constructs into these cells with high efficiency. Unfortunately, we found the cells to be refractory to efficient transfer of DNA using conventional methods (i.e., lipofection, electroporation, or calcium phosphate-mediated transfection). However, replication-defective recombinant human adenoviruses were found to provide a highly efficient means of introducing DNA into the type II pneumonocytes. Furthermore, we observed in type II cell-enriched cultures infected with recombinant adenoviruses containing the lacZ gene under control of a cytomegalovirus promoter, that beta-galactosidase was expressed uniformly in the islands of type II cells and surrounding fibroblasts. By contrast, in cultures infected with recombinant adenoviruses containing the human growth hormone (hGH) gene under control of the SP-A gene promoter and 5'-flanking region, hGH was expressed only in the type II cells. Thus, this culture system provides an excellent means for identifying genomic elements that mediate type II cell-specific gene expression.

Adenoviridae↗

PubMed1997

Ultrasonographic monitoring of antral follicle development in red deer (Cervus elaphus).

Ovarian follicular dynamics were monitored in 12 surgically modified red deer hinds (ovaries adhered to vaginal wall) by transvaginal real-time ultrasonography during the luteal cycle, anoestrus and induction of superovulation. All 12 hinds showed evidence of regular luteal (plasma progesterone) cyclicity during the breeding season, although luteal tissue was not observed on the ultrasonograms. During the normal luteal cycle (14-22 days) total numbers of follicles > 3 mm did not vary significantly by day (range of means: 1.8-3.4; P > 0.05). A single large (> or = 6 mm) follicle was usually present on all days except immediately after ovulation (day 0). However, the appearance of new follicles (> or = 3 mm) was not random, and was greatest on day 1 and day 14 (P < 0.05). Tracking of individual follicles revealed irregular waves of emergence and disappearance of the largest follicle, with either one (n = 1), two (n = 3) or three (n = 5) waves observed across nine luteal cycles. New follicles (> or = 3 mm) emerged after regression or ovulation of a large follicle, suggesting a dominance effect. There were no significant differences in the overall mean numbers of follicles during early, mid- and late anoestrus (September, November and April, respectively) but follicle turnover was more rapid during mid-anoestrus as evidenced by a significantly greater number of new small (> 3 mm) follicles (P < 0.001). Administration of superovulatory doses of ovine FSH during the breeding season resulted in a marked increase in the appearance of new follicles within 48 h of initiation of the injection regimen. By termination at 96 h, the time of progesterone withdrawal, the mean number of follicles > 3 mm was significantly higher than for control hinds (9.8 versus 3.0; P < 0.0001). While most follicles ovulated progressively 2-7 days later, about 40% persisted beyond this period. The study demonstrated the presence of discrete patterns of antral follicle growth and regression during the breeding and non-breeding seasons, with the luteal cycle characterized by a variable number (1-3) of dominant follicle waves. Anoestrus represents a period of dynamic changes in follicular turnover.

Anestrus↗

PubMed1997

A modified step test based on a function of subjects' stature.

A number of submaximal step tests have been developed to predict maximal aerobic capacity. Because step height may influence biomechanical efficiency and heart rate, step tests based on subjects' stature may more accurately predict maximal aerobic capacity. Eighteen women performed the Queens College step test and a modified Queens College step test. The modified step test was performed with the height of the bench set even with the height of the foot at a knee angle of 90 degrees. Analysis of the data indicated a lower recovery heart rate following this test (p < .05). Further, correlations between maximal aerobic capacity and recovery heart rate for both tests were moderate (r = -.80 and -.75, respectively). Our results suggest that step tests based on subjects' stature do not more accurately predict aerobic capacity than those using a standardized bench height.

Adolescent↗

PubMed1997

Planning the milking center in expanding dairies.

This paper focuses on dairies that want to expand and milk more cows through an existing parlor or by building new parlor. The expansion process can be divided into the following three phases: 1) financial evaluation, 2) design, and 3) construction. A financial evaluation should be carried out first to determine the resources that are available for expanding the dairy operation. This phase is extremely important, considering that 68% of the dairies that expand have cash flow problems within the first 2 yr of operation. The next phase is to design the milking center, and options include expanding the present parlor or constructing a new parlor. The present parlor can be expanded by addition of stalls, but group size must also expand to maintain cow flow at the larger parlor size. Group size can often be increased by combining corrals or free-stall alleys. The third phase in the expansion is to determine the most efficient milking procedure during the construction or remodeling of the facilities.

Animals↗

PubMed1997

Venezuelan equine encephalitis and Oropouche virus infections among Peruvian army troops in the Amazon region of Peru.

An outbreak of a febrile illness characterized by headache, ocular pain, myalgia, and arthralgia occurred during June 1994 among Peruvian army troops in Northern Peru. On June 14-16, 1994, clinical data and blood samples were obtained from eight soldiers with a febrile illness, and from 26 others who had a history of febrile illness during the past three months. A follow-up blood sample was obtained 107 days later from four of the febrile and seven of the afebrile soldiers. Serum samples were tested for dengue (DEN), Oropouche (ORO), and Venezuelan equine encephalitis (VEE) IgM and IgG antibodies by an enzyme-linked immunosorbent assay (ELISA). Virus isolation was performed by inoculation of newborn mice and Vero cell cultures. Viral isolates were identified by immunofluorescence, ELISA, and nucleotide sequencing. A VEE virus infection was confirmed in three of the eight febrile soldiers, two by virus isolation, and one by serology. Antigenic analysis indicated that one of the virus isolates was similar to VEE subtype I, variety ID, viruses previously isolated in Colombia and Venezuela. Nucleotide sequence data showed that both viral isolates were identical to one another and closely related to VEE ID viruses previously isolated in Peru, Colombia, and Venezuela. Serologic results showed that two of 26 afebrile soldiers had IgM antibody to VEE and four had IgG antibody to VEE; two febrile soldiers had IgG antibody in their first serum samples. Oropouche-specific IgM antibody was detected in one of the eight febrile and five of the afebrile soldiers, and 18 of the 34 soldiers had low titers of ORO IgG antibody titers, which did not meet the diagnostic criteria for confirmed cases. All soldiers were negative for DEN IgM antibody, and 10 had flavivirus IgG antibody that reacted with DEN antigens. These data indicated that VEE ID virus was one of the causes of illness among Peruvians soldiers and that this was the first association of this VEE subtype with human disease in Peru.

Adolescent↗

PubMed1997

Molecular investigation of a multisource outbreak of Crimean-Congo hemorrhagic fever in the United Arab Emirates.

During the investigation of an outbreak of Crimean-Congo hemorrhagic fever (CCHF) in the United Arab Emirates (UAE) between 1994 and 1995, blood samples from suspected CCHF cases and ticks collected from livestock were tested for CCHF virus by antigen-capture ELISA and by a reverse transcription-polymerase chain reaction. Phylogenetic analysis of partial small (S) segment nucleotide sequences from four ticks and five human samples showed that with one exception, all the human and tick viruses clustered along with samples from Pakistan and Madagascar in one distinct lineage. Within this lineage, sequences from the UAE patients were identical or closely related to those from three Hyalomma spp. ticks obtained from livestock recently imported from Somalia. Another sequence from a UAE patient was more closely related to a CCHF virus from Nigeria. These data indicate that the 1994-1995 CCHF epidemic in the UAE was a multisource outbreak possibly associated with importation of CCHF virus-infected livestock and ticks.

Animals↗

PubMed1997

Immunohistochemical and in situ localization of Crimean-Congo hemorrhagic fever (CCHF) virus in human tissues and implications for CCHF pathogenesis.

BACKGROUND: Crimean-Congo hemorrhagic fever (CCHF) is a potentially fatal disease that occurs in parts of Africa, Asia, and eastern Europe, and that is caused by a recently emerged bunyavirus. Rapid laboratory diagnosis of CCHF infection is essential and is currently performed by virus isolation and serology. Histopathologic studies have been limited to a small number of cases, and little is known about the cellular tropism of CCHF virus and the pathogenesis of this disease. DESIGN: We conducted a retrospective case analysis of 12 patients with a diagnosis of CCHF infection, confirmed by virus isolation, who were evaluated at the Special Pathogens Unit, National Institute for Virology, South Africa. The clinicopathologic features of CCHF and the diagnostic role of virus isolation as compared with serology, immunohistochemistry, and in situ hybridization were evaluated. Additionally, the distribution of CCHF virus in human tissues was examined. RESULTS: The clinical and histopathologic features of CCHF resemble those of other viral hemorrhagic fevers. Of the 12 patients with virus isolation-confirmed CCHF infection, 5 were positive by serology, 10 by immunohistochemistry, and 5 by in situ hybridization. Immunohistochemistry and in situ hybridization analyses showed that the mononuclear phagocytes, endothelial cells, and hepatocytes are main targets of infection. Association of parenchymal necrosis in liver with viral infection suggests that cell damage may be mediated by a direct viral cytopathic effect. CONCLUSIONS: The diagnosis of CCHF, suspected by history and clinical features, can be supported histopathologically. However, since the pathologic features resemble those of other viral hemorrhagic fevers, an unequivocal diagnosis can be made only by laboratory tests. The utility of immunohistochemistry as a sensitive and rapid diagnostic modality was established by the high degree of concordance with virus isolation. Infection of mononuclear phagocytes, endothelial cells, and hepatocytes may play a critical role in the pathogenesis of CCHF.

Adolescent↗

PubMed1996

Complete sequence of Venezuelan equine encephalitis virus subtype IE reveals conserved and hypervariable domains within the C terminus of nsP3.

The complete nuleotide and predicted amino acid sequences of Venezuelan equine encephalitis (VEE) virus subtype IE (isolate 68U201) were determined and compared to those of other antigenic variants within the VEE complex, strains IAB-TrD, IC-P676, ID-3880, IE-Menall, and II-Fe3-7c. The 68U201 structural proteins were most closely related to their Menall counterparts (97--100% identity) and more distantly related to VEE strains of other antigenic varieties (83--93% identity). With the exception of nsP3, the 68U201 nonstructural proteins were 94--95% identical to those of TrD, P676, and 3880 (nonstructural gene sequences are not available for Menall and Fe3-7c). The amino-terminal region of nsP3 (aa 1--329), which is highly conserved among all alphaviruses, was 93--94% identical for all VEE strains. The nsP3 carboxyl region is highly divergent among alphaviruses in general, but well conserved among previously sequenced VEE strains (>90% identity). Surprisingly, the carboxyl region of 68U201 nsP3 (aa 330--563) was only 59--61% identical to that of subtype IAB, IC, and ID viruses, with large insertions and deletions in addition to numerous substitutions. The differences between the 68U201 and other VEE nsP3 carboxyl regions were not randomly distributed, as there were four domains of high similarity within the nonconserved region. To examine this divergence more closely, we sequenced a portion of the Menall ns3 gene. The 68U201 and Menall nsP3 nonconserved regions were 85.3% identical and had the same basic domain structure, which was distinct from the IAB, IC, and ID nsP3 proteins, suggesting that the domain structure of nsP3 may be subtype/variety-specific. VEE nsP3 sequence diversity may reflect ecological differences such as adaptation to different mosquito vectors or vertebrate hosts.

Amino Acid Sequence↗

PubMed1996

Characterization of Langat virus antigenic determinants defined by monoclonal antibodies to E, NS1 and preM and identification of a protective, non-neutralizing preM-specific monoclonal antibody.

Hybridomas secreting monoclonal antibodies (MAb) to the tick-borne encephalitis (TBE) group virus, Langat virus (LGTV), were prepared. Of more than 200 MAb screened, 19 antibodies, which cross-reacted with the etiologic agent of Central European encephalitis, were selected for further characterization. Of these MAb, 15 were specific for LGTV E glycoprotein, two for the NS1 protein, and three for preM protein. The two NS1-specific MAb and two of the E-specific MAb reacted with all six of the other TBE group viruses tested while the remainder of the E-specific MAb failed to recognize at least one of the viruses. None of the MAb neutralized LGTV in cell culture assays, but one of the preM-specific MAb protected weanling mice against a virulent LGTV challenge. Although protective antibodies to E and NS1 proteins of TBE viruses were reported, our data provided the first evidence for protection by a non-neutralizing antibody to the preM or M protein of any of the tick-borne flaviviruses.

Animals↗