Using the systematic review methodology to evaluate factors that influence the persistence of influenza virus in environmental matrices.

Understanding factors that influence persistence of influenza virus in an environment without host animals is critical to appropriate decision-making for issues such as quarantine downtimes, setback distances, and eradication programs in livestock production systems. This systematic review identifies literature describing persistence of influenza virus in environmental samples, i.e., air, water, soil, feces, and fomites. An electronic search of PubMed, CAB, AGRICOLA, Biosis, and Compendex was performed, and citation relevance was determined according to the aim of the review. Quality assessment of relevant studies was performed using criteria from experts in virology, disease ecology, and environmental science. A total of 9,760 abstracts were evaluated, and 40 appeared to report the persistence of influenza virus in environmental samples. Evaluation of full texts revealed that 19 of the 40 studies were suitable for review, as they described virus concentration measured at multiple sampling times, with viruses detectable at least twice. Seven studies reported persistence in air (six published before 1970), seven in water (five published after 1990), two in feces, and three on surfaces. All three fomite and five air studies addressed human influenza virus, and all water and feces studies pertained to avian influenza virus. Outcome measurements were transformed to half-lives, and resultant multivariate mixed linear regression models identified influenza virus surviving longer in water than in air. Temperature was a significant predictor of persistence over all matrices. Salinity and pH were significant predictors of persistence in water conditions. An assessment of the methodological quality review of the included studies revealed significant gaps in reporting critical aspects of study design.

Kinetics of UV(254) inactivation of selected viral pathogens in a static system.

AIMS: The objective of this study was to estimate UV(254) inactivation constants for four viral pathogens: influenza virus type A, porcine respiratory and reproductive syndrome virus (PRRSV), bovine viral diarrhoea virus (BVDV) and reovirus. METHODS AND RESULTS: Viruses in culture medium were exposed to one of nine doses of UV(254) and then titrated for infectious virus. Analysis showed that viral inactivation by UV(254) was more accurately described by a two-stage inactivation model vs a standard one-stage inactivation model. CONCLUSIONS: The results provided evidence for the existence of two heterogeneous viral subpopulations among the viruses tested, one highly susceptible to UV(254) inactivation and the other more resistant. Importantly, inactivation constants based on the one-stage inactivation model would have underestimated the UV(254) dose required for the inactivation of these viruses under the conditions of the experiment. SIGNIFICANCE AND IMPACT OF THE STUDY: To improve the accuracy of estimates, it is recommended that research involving the inactivation of micro-organisms evaluates inactivation kinetics using both one-stage and two-stage models. These results will be of interest to persons responsible for microbial agents under laboratory or field conditions.

The Efficiency of Biofilters at Mitigating Airborne MRSA from a Swine Nursery.

Our prior studies have been in agreement with other researchers in detecting airborne methicillin-resistant Staphylococcus aureus (MRSA) inside and downwind of a swine housing facility. MRSA emitted in the exhaust air of swine facilities creates a potential risk of transmission of these organisms to people in the general area of these facilities as well as to other animals. This study investigated a possible means of reducing those risks. We investigated the efficiency of biofilters to remove MRSA from the exhaust air of a swine building. Two types of biofilter media (hardwood chips and western red cedar shredded bark) were evaluated. Efficiency was measured by assessing both viable MRSA (viable cascade impactor) and dust particles (optical particle courter) in the pre-filtered and post-filtered air of a functioning swine production facility. Our study revealed that hardwood chips were respectively 92% and 88% efficient in removing viable MRSA and total dust particles. Western red cedar was 95% efficient in removing viable MRSA and 86% efficient in removing dust particles. Our findings suggest that biofilters can be used as effective engineering controls to mitigate the transmission of aerosolized MRSA in the exhaust air of enclosed swine housing facilities.

Bispyridinamines: a new class of topical antimicrobial agents as inhibitors of dental plaque.

A series of N,N'-polyalkylenebis[4-(substituted-amino)pyridines] has been prepared, and members have been evaluated as potential anti-dental plaque agents. From among the most active members of the series, one compound, N,N'-[1,10-decanediyldi-1(4H)-pyridinyl-4-ylidene]bis(1-octanam ine) dihydrochloride, octenidine, was selected as a candidate for clinical study.

Parapneumonic empyema in children: decortication hastens recovery in patients with severe pleural infections.

The medical records of 61 children 0 to 18 years of age treated for empyema complicating pneumonia from 1977 to 1989 were reviewed with attention to clinical presentation, bacteriology, treatment and outcome. Streptococcus pneumoniae was the most common infecting organism, followed by Staphylococcus aureus, other streptococcal species, anaerobes, Haemophilus influenzae type b, Pseudomonas aeruginosa, and Eikenella corrodens. No organisms were recovered in 39% of patients. Twelve patients were treated successfully with antibiotics and thoracentesis alone, 23 patients underwent close tube thoracostomy and 26 required decortication. A thickened pleural "peel," scoliosis and opacification of a hemithorax on chest radiograph, as well as low pleural pH and glucose concentration, were associated with a poor response to medical management. A scoring system was developed to define the severity of pleural disease. In patients with severe pleural infections, decortication allowed more rapid defervescence (2.2 vs. 6.5 days) and earlier hospital discharge (4.4 vs. 12.4 days) than did closed tube thoracostomy (P less than 0.001).

Amlodipine reduces graft coronary artery disease in rat heterotopic cardiac allografts.

The long-acting dihydropyridine calcium antagonist, amlodipine, suppresses atherogenesis in experimental animals. To determine the effect of amlodipine on allograft coronary artery disease in the transplanted heart, we used a working heterotopic rat heart transplant model. All rats were immunosuppressed with cyclosporine as a single agent and randomized to a control group (n = 9) and an amlodipine-treated group (n = 9). After 90 days, rats were killed, and the extent of graft coronary artery disease was assessed by digitizing morphometry. No significant differences were noted for mean arterial blood pressure or serum total cholesterol, high-density lipoprotein cholesterol, or triglycerides at the time of death. Amlodipine was associated with significantly less narrowing in the coronary arteries (mean percent narrowing for control group, 48.9% +/- 8.2%; mean percent narrowing for amlodipine group, 25.5% +/- 9.9%; P < 0.05). These findings suggest a role for calcium channel blockers in the prevention of graft coronary artery disease.

Aortobronchial fistula after unilateral lung transplantation.

An aortobronchial fistula resulting in massive hemoptysis developed in a 48-year-old man 13 months after unilateral lung transplantation. His posttransplantation recovery was complicated by bronchial dehiscence requiring revision and subsequent stricture formation treated by granulation tissue excision, placement of endobronchial stents, dilation, and laser photoablation. Early and aggressive treatment using these modalities is necessary in the successful management of airway complications after pulmonary transplantation.

Safety of remote aortic valve replacement after prior coronary artery bypass grafting.

BACKGROUND: A previous coronary artery bypass grafting (CABG) procedure may complicate subsequent aortic valve replacement (AVR). However, the operative risks and long-term outcome of patients who undergo these two procedures remain poorly defined. METHODS: The medical records of all patients undergoing AVR between February 1986 and September 1995 were reviewed retrospectively. The patients selected for analysis had previously undergone CABG. RESULTS: We performed AVR in 23 consecutive patients who had previously undergone CABG (mean number of grafts, 2.8). The AVR was performed an average of 7.6 years after CABG (range, 2 to 17 years). There were 20 men and 3 women, with a mean age of 69 years (range, 56 to 85 years). Twenty patients were operated upon for aortic stenosis (mean gradient 54 mm Hg, mean valve area 0.7 cm2), and 3 patients underwent operation for aortic regurgitation. The average aortic valve gradient at the initial revascularization operation was 8 mm Hg (range, 0 to 29 mm Hg). There was no correlation between the aortic valve gradient at the initial revascularization and the interval between CABG and AVR. At the second operation, AVR was performed alone in 11 patients, combined with repeat CABG in 11 patients (mean number of grafts, 1.4), and with mitral valve replacement in 1 patient. A mechanical prosthesis was selected in 14 patients, and a bioprosthesis was used in 9 patients. There were no perioperative deaths. There were five late deaths at an average follow-up of 44 months. The 5-year actuarial survival was 71%. CONCLUSIONS: Previous CABG poses added technical challenges at the time of reoperation for AVR. The operation can be performed safely, with the expectation of satisfactory long-term survival.

Prognosis of adenocarcinoma arising in Barrett's esophagus.

BACKGROUND: The rising incidence of adenocarcinoma of the esophagus, as well as its association with Barrett's esophagus, has been reported previously. We report our experience in treating patients with adenocarcinoma arising in Barrett's esophagus. METHODS: A retrospective review was performed of 70 consecutive patients with adenocarcinoma of the esophagus treated between November 1988 and April 1996 with preoperative chemoradiation and resection. Demographics, pathologic features, and survival were compared with patients who developed adenocarcinoma of the esophagus without Barrett's. Statistical analyses was performed using Student's t test, Fisher's exact test, and Kaplan-Meier where appropriate. RESULTS: Thirty-two (46%) patients had adenocarcinoma arising in Barrett's esophagus. During the last 4 years, 72% (23 of 32) of patients with adenocarcinoma had coexistent Barrett's. No differences in patients with or without Barrett's with regard to age, sex, race, tumor location, preoperative chemotherapy, type of operation, or operative stage were observed. Tumors in patients with Barrett's were larger (p = 0.017), had better differentiation (p = 0.002), and were less likely to have a complete response to preoperative chemoradiation (p = 0.05). Actuarial survival, however, was better in the group with associated Barrett's esophagus (p = 0.033). CONCLUSIONS: The incidence of adenocarcinoma of the esophagus arising in Barrett's esophagus appears to be increasing. It may be distinct clinically and biologically from adenocarcinoma of the esophagus that does not develop in association with Barrett's epithelium. Long-term survival was better in our patients with adenocarcinoma associated with Barrett's esophagus.

Noninvasive detection of acute rejection in a new experimental model of heart transplantation.

We have shown that positron emission scintigraphy detects changes in the uptake of 18-F 2-deoxyglucose and 13-N ammonia by the acutely rejecting myocardium in a nonworking model of heterotopic heart transplantation in the rat. We developed a new working model of heterotopic heart transplantation to determine the possible relevance of these changes to clinical transplantation. Moderate aortic valvular regurgitation was produced allowing the heterotopic left ventricle to fill and eject. Rejecting allografts and nonrejecting isografts (controls) were studied 4 days after transplantation. Histologically, isografts were normal and all allografts showed mild acute rejection. Decay-corrected uptakes of 18-F 2-deoxyglucose and 13-N ammonia reflect glucose metabolism and blood flow, respectively. Values are presented as percent of injected dose per gram of tissue. Uptake of 18-F 2-deoxyglucose was higher in rejecting allografts compared with nonrejecting isografts (3.0 +/- 1.8 versus 1.1 +/- 0.4; p = 0.024). Ammonia uptake was elevated in allografts compared with isografts (2.2 +/- 0.5 versus 1.3 +/- 0.5; p = 0.023). Uptakes of 18-F 2-deoxyglucose and 13-N ammonia are higher in mildly rejecting allografts, implying increased glucose utilization and blood flow during acute rejection. These data support our earlier findings of changes in myocardial metabolism in the absence of diminishing blood flow in acutely rejecting hearts. This model may lead to a better understanding of the physiology and metabolism of acute rejection.

Operative risk factors and durability of repair of coarctation of the aorta in the neonate.

The risk factors for the operative mortality and long-term durability of repair after surgical correction of coarctation of the aorta in neonates remain controversial. Between January 1970 and January 1993, 139 patients under 1 month of age underwent repair of coarctation of the aorta. Complex intracardiac defects were present in 59 patients. Another 44 patients had an associated ventricular septal defect. Subclavian artery flap repair was performed in 92 patients; end-to-end anastomosis (38 patients) and patch angioplasty (9 patients) were performed less commonly. The hospital mortality was significantly higher in patients with complex intracardiac defects (9 of 59 patients; 15.2%) than in those with a ventricular septal defect (1 of 44 patients; 2.3%) or with isolated coarctation (none of 36 patients; p = 0.007). Elevated pulmonary artery diastolic pressure (p = 0.041) and complex intracardiac anomalies (p = 0.048) were found to be independent predictors of hospital mortality. The presence of a complex cardiac defect (p < 0.001) was an independent predictor of poor long-term survival. Recurrent stenosis requiring reoperation had occurred or balloon dilation had been necessary in 27.9% of the children at 5 years postoperatively. In patients followed up for at least 5 years, the recurrence-free survival was better in those who had undergone subclavian artery flap repair than in those who had undergone end-to-end repair (p = 0.017). When coarctation of the aorta must be repaired in the neonate, operative mortality and long-term survival are affected by the complexity of associated intracardiac anomalies.(ABSTRACT TRUNCATED AT 250 WORDS)

Preliminary results with neoadjuvant therapy and resection for esophageal carcinoma.

Between December 1988 and August 1992, 68 patients with adenocarcinoma (n = 39) and squamous carcinoma (n = 29) of the esophagus were entered prospectively in a treatment protocol to receive two cycles of cisplatin, 5-fluorouracil, etoposide, leucovorin, and 3,000 cGy of radiation to the involved esophagus and adjacent mediastinum, followed by resection. There were four deaths during chemotherapy, and 7 patients had a decline in condition or were denied operation. Fifty-six patients have come to operation, and 1 awaits resection. Twenty-two patients had transhiatal esophagectomy and 29 patients had esophagogastrostomy with a combined abdominal and right thoracic approach. Five patients did not undergo resection at operation. There was one hospital death (2%). A complete response to preoperative therapy was seen in 12 patients (21%): 5 of 20 with squamous cancer (25%) and 7 of 36 with adenocarcinoma (19%). Average follow-up is 19 months. Median survival in these patients after entrance in the protocol is 24 months. Actuarial survival at 12, 18, and 24 months is 72% (confidence limits, 66% and 78%), 53% (confidence limits, 46% and 60%), and 51% (confidence limits, 44% and 58%). Significantly better survival was associated with adenocarcinoma (p = 0.041). There is no survival advantage based on complete response to preoperative therapy. This neoadjuvant regimen is effective in patients with squamous carcinoma and adenocarcinoma. These preliminary results demonstrate an improved median and actuarial survival compared with historical controls in 137 patients operated on between 1966 and 1985 at our institution.

Noninvasive detection of heart transplant rejection with positron emission scintigraphy.

Positron emission tomography has recently been used to evaluate ischemic heart disease through changes in myocardial blood flow and carbohydrate metabolism. Positron-emitting tracers were evaluated for their ability to detect acute allograft rejection after heterotopic cardiac transplantation in the rat. Sham-operated controls, nonrejecting isografts, and rejecting allografts were evaluated. Decay-corrected uptake of 13NH3 and 18F 2-fluoro 2-deoxyglucose (FDG) reflects blood flow and glucose flux, respectively. Histologic examination of rejecting allografts documented mild rejection at 4 days and severe acute rejection by 8 days. All isografts were free from rejection. Uptake of FDG is greater in rejecting allografts than in nonrejecting isografts during both severe rejection (2.4% +/- 0.8% versus 0.7% +/- 0.4%; p less than 0.02) and mild rejection (2.1% +/- 0.6% versus 0.4% +/- 0.1%; p less than 0.02). Uptake of NH3 in severely rejected grafts is reduced compared with nonrejecting grafts (0.6% +/- 0.3% versus 1.7% +/- 1.1%; p less than 0.02). There is no difference in NH3 uptake during mild rejection (1.8% +/- 0.7% versus 1.3% +/- 0.3%; p greater than 0.05). Uptake of FDG and NH3 in native hearts of animals from all experimental groups is not significantly different from that in sham-operated controls. Glucose may be a preferred metabolic substrate during rejection. Our data support a humoral mechanism for substrate preference during transplant rejection and a potential diagnostic role for positron emission tomography.

Outcome of isolated pulmonary contusion in blunt trauma patients.

To determine outcome in young, healthy blunt trauma patients with isolated pulmonary contusion, and to identify factors associated with poor outcome, we reviewed 6012 consecutive adult (aged 16-49) blunt trauma admissions. Ninety-four (7.9%) presented with an isolated pulmonary contusion defined by chest radiograph and Injury Severity Score < 25; they compromise the study group. Poor outcome was defined as death, prolonged hospitalization (> 7 days), or a severe complication (pneumonia, empyema, atelectasis requiring bronchoscopy, or bronchopleural fistula). None of the 94 study patients died. Admission chest radiograph demonstrated no contusion in 34 patients (36%). Fifteen patients (16%) required intubation, but 13 were extubated within 48 hours. Forty-one patients (44%) required insertion of a chest tube, and 20 patients (21%) had a PaO2/FiO2 ratio of < 250 on admission. Post-injury atelectasis (n = 17), pneumothorax (n = 17), effusion (n = 8), pneumonia (n = 2), empyema (n = 1), and Staphylococcal bacteremia (n = 1) complicated hospitalizations. The following clinical factors were identified as predisposing to poor outcome by univariate analysis: 1) Pulmonary contusion on admission chest radiograph (P = 0.035); 2) Three or more rib fractures (P = 0.002); 3) chest tube insertion (P = 0.010) and drainage (P = 0.020); and 4) hypoxia on admission (PO2 < 70 torr [P = .021], PaO2/FiO2 < 250 [P < 0.001]). Only PaO2/FiO2 < 250 on admission was an independent predictor of poor outcome in a multivariate analysis (P = 0.040). Our conclusion was that isolated pulmonary contusion in young, healthy patients is not associated with mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of blunt and penetrating injury of the innominate and subclavian arteries.

Injury to the innominate or subclavian artery is an uncommon but difficult management problem. Review of trauma admissions from August 1983 to August 1992 revealed 21 patients who sustained injury to the innominate or subclavian artery. Eight patients sustained blunt trauma, while 13 patients sustained penetrating injuries. The mechanism of injury was variable, and associated injuries were common in both blunt and penetrating trauma. Injuries involved the right innominate or subclavian artery in 10 patients and the left subclavian artery in 11 patients. Twenty patients were managed operatively. Primary repair was preferred for penetrating injuries, whereas a bypass graft was more common for blunt injuries (P = 0.41). Patients with penetrating injury were more unstable at presentation (admission systolic blood pressure 73 mm Hg vs 119 mm Hg, P = 0.006; preoperative evaluation time 66 min vs 319 min, P = 0.002) and required more blood transfusions (5 units vs 26 units, P = 0.007) than patients with blunt injuries. Mortality for the entire series was 24 per cent (0% blunt vs 38% penetrating, P = 0.047). Hospital days (28 vs 48) and ICU days (8 vs 14) were longer for survivors of penetrating injuries (P = NS). Complications were common in both groups. Innominate/subclavian artery injury remains a significant cause of mortality and morbidity.

Single lung transplantation: a temporal look at rejection, infection, and survival.

Single lung transplantation (SLT) has emerged as routine therapy for selected patients with end-stage lung disease. This study examines the incidence of rejection, infection, and survival during the first posttransplant year. Twenty-one patients (12 male, 9 female; mean age 46 +/- 13 years) underwent 23 SLT procedures (12 left, 11 right lung). Indications were pulmonary fibrosis in six, emphysema in seven, primary pulmonary hypertension in three, Eisenmenger's syndrome in one, pulmonary veno-occlusive disease in one, a-1 antitrypsin deficiency in two, CREST syndrome in one, and retransplantation (graft failure and bronchiolitis obliterans) in two. All were maintained on triple immunotherapy. Survival at 1 year was 100%. The five patients with preoperative pulmonary hypertension had normal hemodynamics at follow up. Freedom from event at 1 year was rejection 23 per cent, all infections 6 per cent, viral 40 per cent, bacterial 55 per cent, fungal 74 per cent. At 1 year, cumulative incidence (events/patient-year) was rejection 1.61, all infections 2.18, viral 0.78, bacterial 1.12, fungal 0.28. Two of 21 patients have developed bronchiolitis obliterans at 1 and 2 years posttransplant. SLT provided safe, effective treatment for a wide variety of end-stage lung diseases. Rejection and infection, although common, may be safely treated with resolution.

Postpneumonic empyema in childhood: selecting appropriate therapy.

In order to identify appropriate treatment options for postpneumonic empyema, we reviewed the medical records and, when possible, obtained long-term follow-up chest radiographs and pulmonary function tests on children treated for empyema during the past 11 years. Fifty-one patients were treated in various ways, with antibiotics alone (N = 10), or in combination with tube thoracostomy (N = 23) or decortication (N = 18). Despite administration of appropriate antibiotics and establishment of pleural drainage, many children required prolonged hospitalization and eventual decortication. Based on this review, a scoring system was developed allowing early classification by severity of pleural disease. Factors found to be predictors of severe pleural disease include (1) low pleural fluid pH or (2) glucose; (3) presence of moderate or severe scoliosis or (4) pleural peel or parenchymal entrapment by chest radiography; and (5) infection due to anaerobes, gram-negative organisms, or mycoplasma. Complete opacification of a hemithorax on chest radiography and a pleural peel to thoracic ratio greater than 40% were also associated with severe pleural disease. In patients with mild disease (N = 7), response to antibiotics alone, rapid resolution of fever, and shorter hospital stays were observed. In patients with more severe infections (moderate = 22, severe = 22), decortication accomplished earlier defervescence, radiographic improvement, and hospital discharge than simple tube thoracostomy. No deaths or morbidity were associated with decortication, which could often be accomplished through a minithoracotomy. Follow-up chest radiographs and pulmonary fuction tests showed a prompt return to normal after decortication. This experience indicates utility of a pleural disease severity scoring system in selection of treatment options for children with postpneumonic empyema.(ABSTRACT TRUNCATED AT 250 WORDS)

Early development of aggression in chickens: The relative importance of pecking and leaping.

A longitudinal study (employing a multiple separation technique) of chicks' social behavior over the first postnatal month indicated systematic changes in their mode of physical interactions. During the first week or so, intersubject pecking in same-sex pairs was frequent, and was more likely in birds with a home cage advantage (i.e., a prior resident effect). However, there were no sex differences in any of the forms of social pecking (head, body, or feet of the opponent), and all types showed significant decreases over the period of the study. On the contrary, there was a strong effect for sex on rates of aggressive leaping, with males exhibiting more leaps than females. Further, there was a clear increase in leaping over the first weeks of testing, and something of a decline thereafter. These data suggest that in this species the definitive expression of aggressive or dominance behavior may be leaping. Early social pecking (during a period in which this behavior was at its maximum rate) did not predict the subsequent leaping behavior of individuals, but later "leap orders" were highly associated with later "peck orders".

Using olfactometry to measure intensity and threshold dilution ratio for evaluating swine odor.

Intensity and threshold dilution ratio are two important indices for odor control of swine buildings. Although odor threshold dilution ratio is a widely used index to describe an odor, it should be related to intensity to be more useful. A method was proposed to measure both indices simultaneously by using a dynamic forced-choice olfactometer. Four air samples were taken from each of four swine rooms including farrowing, finisher, gestation, and nursery. A panel of eight people was used to evaluate odor intensity. Odor threshold dilution ratios were calculated according to the American Society for Testing and Materials (ASTM) Standard Practice E679-91 to be 333, 424, 25, and 221 for samples collected from farrowing, finisher, gestation, and nursery rooms, respectively. After the samples were diluted 14.7 times, the odor intensities were evaluated to be 3.79, 3.46, 0.48, and 4.0 for the above-mentioned rooms, respectively. The data collected were used to develop a mathematical model.

Breakage and deformation characteristics of hypodermic devices under static and dynamic loading.

OBJECTIVE: To characterize the strength and limitations of hypodermic needles to reduce the risk of leaving broken needles in the flesh of animals. SAMPLE POPULATION: Skin of porcine cadavers. Procedure-Stainless steel needles of various gauges combined with aluminum and plastic hubs were subjected to standard test-stand conditions to compare strength under various loading regimens. A device that simulated animal motion was constructed to test breakage characteristics during animal movement. RESULTS: Needles and needle/hub assemblies were resilient to needle breakage, except when bent needles were straightened and a load reapplied. Needle gauge and length drastically affected strength. For 16-and 20-gauge needles, a 1.0-in needle was 1.6 times stronger than a 1.5-in needle. Adding animal movement for 20-gauge, 1.5-in needles resulted in a 40% increase in hub failures for plastic, compared to aluminum hub needles. CONCLUSIONS AND CLINICAL RELEVANCE: Findings of this study are important considerations for meat packers to address in their Hazard Analysis and Critical Control Points plans.