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Biomedical subjects

J Hayes

Publications and source records attributed to J Hayes.

At least 37 records · Page 2Linked to original sources
PubMed2001

Comparative pathogenesis of tissue culture-adapted and wild-type Cowden porcine enteric calicivirus (PEC) in gnotobiotic pigs and induction of diarrhea by intravenous inoculation of wild-type PEC.

Porcine enteric calicivirus (PEC/Cowden) causes diarrhea in pigs, grows in cell culture, and is morphologically and genetically similar to the Sapporo-like human caliciviruses. Genetic analysis revealed that the tissue culture-adapted (TC) Cowden PEC has one distant and three clustered amino acid substitutions in the capsid region and 2 amino acid changes in the RNA polymerase region compared to wild-type (WT) PEC (M. Guo, K.-O. Chang, M. E. Hardy, Q. Zhang, A. V. Parwani, and L. J. Saif, J. Virol. 73:9625-9631, 1999). In this study, the TC PEC, passaged in a porcine kidney cell line, and the WT PEC, passaged in gnotobiotic (Gn) pigs, were used to orally inoculate 13 4- to 6-day-old Gn pigs. No diarrhea developed in the TC-PEC-exposed pigs, whereas moderate diarrhea developed in the WT-PEC orally inoculated pigs, persisting for 2 to 5 days. Fecal virus shedding persisting for at least 7 days was detected by both reverse transcription (RT)-PCR and antigen-enzyme-linked immunosorbent assay (antigen-ELISA) in both TC-PEC and WT-PEC orally inoculated pigs but not in mock-inoculated pigs. The PEC particles were detected by immunoelectron microscopy (IEM) in intestinal contents from all the WT-PEC-inoculated pigs, but not from the TC-PEC-inoculated pigs. Mild (duodenum and jejunum) or no (ileum) villous atrophy was observed in histologic sections of the small intestines of TC-PEC-inoculated pigs, whereas WT PEC caused mild to severe (duodenum and jejunum) villous atrophy and fusion. Scanning electron microscopy confirmed mild shortening and blunting of villi in the duodenum and jejunum of the TC-PEC-inoculated pigs, in contrast to moderate to severe villous shortening and blunting in the duodenum and jejunum of WT-PEC-inoculated pigs. Higher numbers of PEC antigen-positive villous enterocytes were detected by immunofluorescent (IF) staining in the proximal small intestine of the WT-PEC-inoculated pigs, in contrast to low numbers of PEC antigen-positive enterocytes in only one of four TC-PEC-inoculated pigs. No PEC antigen-positive cells were observed in the colon or extraintestinal tissues of all inoculated pigs or in the small intestine of one mock-inoculated pig. Thus, the TC PEC was at least partially attenuated (no diarrhea, mild lesions) after serial passage in cell culture. In further experiments, three 4- to 6-day-old Gn pigs were intravenously (i.v.) inoculated with WT PEC, and all pigs developed diarrhea and villous atrophy in the small intestines resembling that observed in the orally inoculated pigs. Fecal viral shedding persisting for 8 days was detected by both RT-PCR and antigen-ELISA, and PEC was detected by IEM in feces or intestinal contents. The PEC RNA and antigens (at low titers) were detected in acute-phase sera from all the WT-PEC i.v.-inoculated pigs and also from seven of nine of the WT-PEC orally inoculated pigs. Oral or i.v. inoculation of four additional pigs with the PEC-positive acute-phase sera induced diarrhea, small intestinal lesions, PEC shedding in feces, and seroconversion to PEC, confirming the occurrence of viremia during PEC infection, with infectious PEC present in acute-phase sera. No diarrhea, histopathologic changes, or IF staining in the small intestine or fecal or serum detection of PEC was evident in two pigs i.v. mock-inoculated or a pig inoculated i.v. with inactivated WT PEC. To our knowledge, this is the first report of an attenuated enteric calicivirus, the induction of diarrhea, and intestinal lesions in Gn pigs caused by i.v. inoculation of WT PEC and the presence of viremia following PEC infection.

Animals↗
PubMed2001

Geographic variation of notified Ross River virus infections in Queensland, Australia, 1985-1996.

The spatial and temporal variations of Ross River virus infections reported in Queensland, Australia, between 1985 and 1996 were studied by using the Geographic Information System. The notified cases of Ross River virus infection came from 489 localities between 1985 and 1988, 805 between 1989 and 1992, and 1,157 between 1993 and 1996 (chi2(df = 2) = 680.9; P < 0.001). There was a marked increase in the number of localities where the cases were reported by 65 percent for the period of 1989-1992 and 137 percent for 1993-1996, compared with that for 1985-1988. The geographic distribution of the notified Ross River virus cases has expanded in Queensland over recent years. As Ross River virus disease has impacted considerably on tourism and industry, as well as on residents of affected areas, more research is required to explore the causes of the geographic expansion of the notified Ross River virus infections.

Alphavirus Infections↗
PubMed2001

Human and insect mitochondrial DNA analysis from maggots.

During the course of our forensic investigations, we have encountered situations where it would have been useful to have evidence, other than direct contact between the two, for concluding that a carrion-fly maggot developed on a particular human victim. If a maggot collected during a death investigation did not develop on the victim, then its age is not relevant to estimating the postmortem interval. In this study we demonstrate that mitochondrial DNA (mtDNA) sequence data can be obtained from the dissected gut of a maggot that had fed on human tissue. These data can be used to identify both the human corpse upon which the maggot had been feeding and the species of the maggot itself.

Animals↗
PubMed2000

Molecular characterization and pathogenesis of transmissible gastroenteritis coronavirus (TGEV) and porcine respiratory coronavirus (PRCV) field isolates co-circulating in a swine herd.

TGEV replicates in intestinal enterocytes and causes diarrhea in young pigs. PRCV, a spike (S) gene deletion mutant of TGEV with an altered respiratory tissue tropism, causes mild or subclinical respiratory infections. Comparisons of TGEV and PRCV strains suggest that tropism and pathogenicity are influenced by the S gene and ORF3, respectively. Recently, outbreaks of TGE of reduced virulence were reported in the field. We investigated a similar suspect TGEV outbreak of reduced virulence in nursery pigs from a swine herd in the Midwest. A TGEV strain (BW021898B) was isolated in swine testicular cells from gut contents of a diarrheic pig and three PRCV strains (BW126, BW154, BW155) were isolated from nasal swabs from normal TGEV-seronegative sentinel pigs in contact with the diarrheic pigs. Sequence analysis of the TGEV isolate in the partial S gene and ORF3/3a and ORF3-1/3b revealed high homology with enteropathogenic TGEV strains. Gnotobiotic pig inoculation and histopathological results revealed that this TGEV isolate retained virulence even though in the field outbreak the diarrheal disease was of reduced severity. Sequence analysis of the S gene deletion region of the three PRCV isolates revealed identical deletions between nt 105-752, which differ from deletions previously reported among PRCV strains. The three PRCV isolates had variable sequence changes in ORF 3/3a and ORF 3-1/3b, affecting the ORF size and amino acid sequence. Thus, sequence analysis and pathogenicity studies indicate that this TGEV isolate resembles other enteropathogenic TGEV strains. Therefore, the reduced severity of TGE observed in this herd may be due to the ongoing PRCV infections, which induce antibodies cross-reactive with TGEV and result in decreased disease severity. The results outlined in this study highlight the need to monitor the molecular epidemiology of TGEV/PRCV strains with sensitive differential diagnostic assays, followed by sequence analysis of the critical regions to identify changes and pathogenicity studies to confirm the disease potential of the TGEV isolates.

Amino Acid Sequence↗
PubMed2000

Incidence and predictors of atrial flutter in the general population.

OBJECTIVES: The goal of our study was to determine the incidence and predictors of atrial flutter in the general population. BACKGROUND: Although atrial flutter can now be cured, there are no reports on its epidemiology in unselected patients. METHODS: The Marshfield Epidemiological Study Area (MESA), a database that captures nearly all medical care among its 58,820 residents was used to ascertain all new cases of atrial flutter diagnosed from July 1, 1991 to June 30, 1995. To identify predisposing risk factors, we employed an age- and gender-matched case-control study design using eight additional variables. RESULTS: A total of 181 new cases of atrial flutter were diagnosed for an overall incidence of 88/100,000 person-years. Incidence rates ranged from 5/100,000 in those <50 years old to 587/100,000 in subjects older than 80. Atrial flutter was 2.5 times more common in men (p < 0.001). The risk of developing atrial flutter increased 3.5 times (p < 0.001) in subjects with heart failure and 1.9 times (p < 0.001) for subjects with chronic obstructive pulmonary disease. Among those with atrial flutter 16% were attributable to heart failure and 12% to chronic obstructive lung disease. Three subjects (1.7%) without identifiable predisposing risks were labeled as having "lone atrial flutter." CONCLUSIONS: This study, the first population-based investigation of atrial flutter, suggests this curable condition is much more common than previously appreciated. If our findings were applicable to the entire U.S. population, we estimate 200,000 new cases of atrial flutter in this country annually. At highest risk of developing atrial flutter are men, the elderly and individuals with preexisting heart failure or chronic obstructive lung disease.

Adult↗
PubMed2000

Self-determination and empowerment: a feminist standpoint analysis of talk about disability.

In this paper we offer a feminist analysis of talk about self-determination and empowerment in the context of disability, focusing on the case of developmental disabilities. We find strains of the same patterns feminist epistemologists have argued shape the organization of formal knowledge from the standpoint of the privileged. At the extreme, people with developmental disabilities appear as objects without selves, outside of the context of interpersonal and social structural relationships that constrain who they can be by defining them as other, often in multiple and interacting ways. Empowerment, from the dominant standpoint, becomes an abstract attribute or condition; something a person has or does not have. Taking the standpoint of women and other marginalized people offers a view of self-determination as a person's development of his or her self. Empowerment becomes a potential characteristic of a social relationship, one that facilitates the development of someone's self. The most empowering relationships are mutual, recognizing and building on the diverse contributions and needs of participants in ways that seek to minimize inequalities over time. The reason some of us are self-determining is that we are in interpersonal and social structural relationships that empower us. To construct interpersonal and social structural relationships that empower people with developmental disabilities requires challenging the way dominant conceptualizations of independence and productivity also express the standpoint of the privileged. The standpoint of women allows all of us to talk more of how we connect with and facilitate one another's developing selves within communities.

Developmental Disabilities↗
PubMed2000

Entrainment of segmental small intestinal slow waves with electrical stimulation in dogs.

The aim of this study was to derive effective pacing parameters for the entrainment of segmental intestinal myoelectrical activity. The study was performed in 12 dogs. Four pairs of electrodes were implanted on the serosa of the jejunum. Electrical stimulation of the small intestine was performed via the most proximal pair. For the slow waves within a distance of 5 cm, a complete entrainment was achieved with a pacing frequency of 1.1 times the intrinsic frequency (IF), a pulse width of 140 msec, and an amplitude of 4 mA. The time required for the entrainment was 25.6 +/- 2.7 sec. The maximum driven frequency was 1.38 +/- 0.03 IF. The percentage of the entrainment at this frequency was 44.0 +/- 3.9%. The data indicate that pacing is able to completely entrain segmental intestinal myoelectrical activity, suggesting that normalization of intestinal myoelectrical dysrhythmia is feasible with pacing.

Animals↗
PubMed2000

Microchimerism and rejection: a meta-analysis.

AIMS: To study the relationship between graft rejection and microchimerism with and without donor bone marrow infusion in recipients of kidney, liver, heart and lung transplants. Selection of manuscripts. Thirty-seven manuscripts presenting clinical data on microchimerism and rejection, published between 1991 and 1997, were identified. Of these, 16 were excluded due to duplication or insufficient data. Inclusion criteria were data on microchimerism, bone marrow infusion and rejection episodes. STATISTICAL TESTS: A mixed effect logistic model was used to test for homogeneity of transplant centers. The centers were found to be homogeneous for rejection rates controlling for microchimerism and bone marrow infusion. Using rejection episodes at 3, 6, and 12 months post-transplant as the outcome, we evaluated logistic regression models to derive odds ratios for rejection with microchimerism and with bone marrow infusion for each organ. RESULTS: Microchimerism was generally associated with a higher incidence of acute rejection for heart, lung, and kidney transplants and a lower incidence for liver transplants, especially at 12 months and above. Bone marrow infusion decreased the risk of acute rejection for heart transplants and increased the risk for lung and, to a lesser extent, for liver transplants. No consistent effect was seen in kidney transplants. At 12 months and longer, microchimerism was associated with a decreased incidence of chronic rejection in recipients of lung transplants, but there were insufficient data to determine this outcome for other organs. CONCLUSIONS: (i) Microchimerism was detected in the majority of patients. (ii) The effect of microchimerism and bone marrow infusion on rejection episodes varied with the organ and, for a given organ, it was time-dependent. (iii) These findings demonstrate the need for more extensive studies on microchimerism and donor-specific hyporesponsiveness.

Graft Rejection↗
PubMed2000

Placement of nasoenteral feeding tubes using magnetic guidance: retesting a new technique.

OBJECTIVE: To study a new technique of intubating the small bowel using a newly developed nasoenteral feeding tube fitted with a magnet in its tip and guided for placement with an external magnet. METHODS: The study was performed in medical and surgical wards of a university-affiliated Department of Veterans Affairs hospital on 42 patients referred by their attending physicians for tube placement. The newly designed feeding tube was inserted per nares into the stomach using traditional technique. As the tube was advanced, movement of the hand-held steering magnet was designed to guide the tip of the magnetic nasoenteral tube along the lesser curvature of the stomach, through the pyloric sphincter, and into the duodenum. Portable abdominal radiography confirmed the anatomic location of the tube tip. RESULTS: Fifty-one intubations were performed on 42 subjects. In 45 intubations (88%), tubes passed into the duodenum. Twenty-seven (53%) met criteria for optimal placement in the second portion of the duodenum or distally. Six of 11 tubes (55%) that were not optimally placed were advanced to the distal duodenum on repositioning. Median procedure time for the initial intubations was 30 minutes (interquartile range 15-40). Median procedure time for last 10 intubations improved to 13 minutes (interquartile range 5-20). No complications were related to the procedure. CONCLUSIONS: Enteral feeding tube placement using external magnetic guidance is a promising, novel technique which is deserving of further study.

Adult↗
PubMed2000

Efficacy, safety and tolerability of combined administration of lithium and selective serotonin reuptake inhibitors: a review of the current evidence. Hertfordshire Neuroscience Research Group.

Several case reports have engendered concern about the safety of coadministering lithium and selective serotonin reuptake inhibitor (SSRI) antidepressants and there are theoretical reasons to suppose that lithium and serotonergic antidepressants may be associated with dangerous interactions. Systematic reports regarding combination therapy with lithium and SSRI antidepressants were assimilated for the purpose of this review. Although there are many publications, few are directly informative as to safety and tolerability. A total of 503 patients are considered in systematic reports and, among these, no serious or life-threatening adverse events can be identified. Such data as there are demonstrate little potential for toxic interactions between lithium and SSRIs, although new, non-serious, adverse events do frequently arise. The evidence for the efficacy of addition of lithium to SSRIs in treatment refractory depression is only provisional.

Antimanic Agents↗
PubMed2000

Entrainment of intestinal slow waves with electrical stimulation using intraluminal electrodes.

The aim of this study was to investigate whether the intestinal stimulation would be feasible using a less invasive method: intraluminal electrodes. The study was performed in nine healthy hound dogs (15-26 kg). Four pairs of electrodes were implanted on the serosa of the jejunum at an interval of 5 cm with the most proximal pair 35 cm beyond the pylorus. An intestinal fistula was made 20 cm beyond the pylorus. Simultaneous recordings of intestinal myoelectrical activity were made for 2 h in the fasting state from both intraluminal and serosal electrodes. Various pacing parameters were tested. The frequency of the intestinal slow wave recorded from the intraluminal electrodes was identical to that from the serosal electrodes (18.78+/-0.3 cpm vs 18.75+/-0.3 cpm, r=0.99, p <0.001), and so was the percentage of normal 17-22 cycles/ min waves (95.83+/-3.9% vs 98.16+/-1.33%, r=0.96, p<0.01). A complete entrainment of the intestinal slow wave was achieved in every dog with electrical stimulation using intraluminal ring electrodes. The effective pacing parameters were pulse width of 70 ms, amplitude of 4 mA and frequency of 1.1 IF (intrinsic frequency). The time required for the entrainment of the intestinal slow wave with intraluminal pacing was 25.0+/-2.1 s. The maximum driven frequency was found to be 1.43+/-0.01 IF. The results reveal that intraluminal pacing is an effective and efficient method for the entrainment of intestinal slow waves. It may become a potential approach for the treatment of intestinal motor disorders associated with myoelectrical abnormalities.

Animals↗
PubMed2000

Supervising trauma life support by telemedicine.

The resuscitation room in a community hospital was linked with a main hospital accident and emergency department using telemedicine equipment working at 384 kbit/s. Fifteen simulated casualties replicated the 'moulage' scenarios in the Advanced Trauma Life Support Course Manual of the American College of Surgeons. Each of the 15 scenarios was broken down into three main parts: the primary survey, resuscitation and the secondary survey. While a physician in the community hospital undertook each task, a senior doctor in the accident and emergency department recorded his degree of confidence in the supervision of the task on a five-point scale. There were features of the management which the supervisor found difficult, mainly related to the camera view and the use of a proxy examiner. However, supervising major trauma management by telemedicine was feasible. The average scores were mostly above 3 and often above 4 in the assessment of the primary survey and the resuscitation. The average scores were mostly above 3 for the secondary survey but were less often above 4 than for the primary survey and the resuscitation. Trials of remote trauma management with real patients appear to be justified.

Feasibility Studies↗