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Biomedical subjects

J Bos

Publications and source records attributed to J Bos.

At least 19 recordsLinked to original sources
PubMed2006

Equine trypanosomosis in the Central River Division of The Gambia: a study of veterinary gate-clinic consultation records.

The objective of this study was to provide epidemiological information of equine trypanosomosis in the Central River Division (CRD) of The Gambia. Therefore, 2285 consultations records of equines, admitted in a gate-clinic at Sololo in CRD, were studied retrospectively. The data were recorded in the period between September 1995 and July 2002 and comprised consultations of 2113 horses and 172 donkeys. 'Trypanosome infection' was the most frequently diagnosed condition and accounted for 61% of the cases. Horses were more frequently diagnosed with trypanosome infections than donkeys (p<0.001), with an occurrence of 63% compared to 43% in donkeys. In both horses and donkeys, trypanosome infections were mainly due to Trypanosoma congolense (64%) and T. vivax (32%). There was no difference observed in the occurrence of trypanosome infections in male or female donkeys (p=0.585), but there were more female (67.8%) horses observed with trypanosome infections than male horses (60.7%; p=0.003). There was no difference observed in the occurrence of trypanosome infections in donkeys older or younger than 1 year (p=0.130), but more older horses (63.2% >1 year) were observed with trypanosome infections than young horses (54.5% <1 year; p=0.033). The number of donkeys and horses with trypanosome infections decreased during the rainy season (June-September). The majority of equines that were admitted with trypanosome infections were severely anaemic. The average packed cell volume (PCV) declined with increasing parasitaemia (p=0.006). Seventy-four percent of the farmers' predictions of trypanosome infections in their equines were confirmed by darkground-microscopy. That proved that farmers had a fairly accurate knowledge of the diseases affecting their equines. The treatments executed at the gate-clinic were generally effective. The few (0.4%) relapses of the T. vivax infections that were previously treated with diminazene aceturate in this study were not sufficient to prove drug resistance. The study showed that the analysis of consultation records at a gate-clinic can provide complementary information to conventional epidemiological studies in the same research area.

Age Factors↗
PubMed2005

Susceptibility of West African Dwarf goats and WAD x Saanen crosses to experimental infection with Trypanosoma congolense.

West African Dwarf goats (WADs) and their Saanen crosses were experimentally infected with Trypanosoma congolense. No significant differences were found between trypanosome parasitaemia and antibody response of the crossbred and WAD goats. Neither the WAD goats nor the Saanen crosses were able to control the drop in PCV following trypanosome infection. The level of anaemia caused by the trypanosome infection was similar in the two breeds during the trial. Based on these findings, no difference in tolerance or susceptibility to T. congolense could be demonstrated between the WAD goats and their Saanen crosses. Although the weight of all goats increased during the trial, the crosses gained significantly more weight than the WAD goats. The trypanosome infection reduced the growth rate of both breeds, but this reduction was not statistically significant. Crossbreeding trypanotolerant WADs with trypanosusceptible Saanen goats might, therefore, be an effective means of increasing productivity.

Animals↗
PubMed2002

Effects of diesel exhaust enriched concentrated PM2.5 in ozone preexposed or monocrotaline-treated rats.

Epidemiological studies have observed statistical associations between short-term exposure to increased ambient particulate air pollution and increased hospital admissions, medication use, pulmonary morbidity, and mortality. To examine the effects of particle air pollution in animals, rats with a preexisting pulmonary inflammation (induced by 1600 microg/m(3) ozone) or hypertension (induced by monocrotaline, MCT) were nose-only exposed to concentrated freshly generated diesel exhaust particles (DEP) mixed with ambient air (CDP). It was hypothesized that a single 6-h exposure to PM exacerbates respiratory inflammatory processes, which affects health parameters in the blood. Histopathology of lung and nose, bronchiolar lavage (BAL), and blood analyses were performed at 1, 2, and 4 days after of the CDP exposure. Morphometry of BrdU-labeled cells in lung and nose was performed at 4 days postexposure. One day after ozone exposure, a mild inflammatory reaction in the centriacinar area was present, consisting of an increase in cellularity of septa and in the number of alveolar macrophages, decreasing in time. Additional CDP exposure did not influence this pattern, except for alveolar macrophages that were loaded with CDP. The only effect seen in the nose after ozone exposure was a slight hypertrophy of the septal mucous cells. Additional exposure to CDP did not change this appearance. MCT-treated rats showed hypertrophy of the media of the pulmonary muscular arteries that was not effected by CDP. BrdU labeling of predominantly Clara cells in the terminal bronchioles was significantly increased after ozone exposure as well as after MCT treatment, whereas this labeling index was markedly enhanced after an additional exposure to CDP. However, no increases in Clara cell protein (CC16) levels were measured of Clara cell protein (CC16) in either BAL or blood. BrdU labeling in the nasal epithelium was not influenced by exposure to ozone or ozone + CDP. CDP exposures did not induce significant toxic effects in the lungs. CDP exposures clearly induced an oxidative stress that was indicated by increasing glutathione levels in BAL with time. In addition, blood fibrinogen levels were enhanced in pulmonary hypertensive rats exposed to CDP. The present study demonstrates that very high CDP concentrations are needed to result in pulmonary changes in animal models with a preexisting pulmonary inflammation or hypertension that continue for days after a single exposure. In addition, CDP has the potential to induce changes in blood. It has not yet been determined how the effects seen with CDP would compare to similar levels of ambient particles.

Air Pollutants↗
PubMed2002

Definition and assessment of specific occupational demands concerning lifting, pushing, and pulling based on a systematic literature search.

AIMS: (1) To find a universal strategy for the identification of specific demands of a job or task, focusing on occupations in which there may be an increased risk for health complaints owing to these specific demands. (2) To select reliable and valid tests concerning lifting, pushing, and pulling, which consider the relation between occupational work demands and the assessment of the maximally acceptable load on an individual level. METHODS: Literature search was performed using Medline (1988 to May 2001), Embase (1966 to May 2001), and NIOSHTIC (1971-98). RESULTS: No universal strategy was found for the definition of specific occupational demands. Therefore a "three step strategy" was formulated for defining specific occupational demands in a job or a task in order to prevent health complaints on an individual level. Many tests were found in the literature concerning lifting, but only a few concerning pushing and pulling. None of the tests concerning pushing, pulling, or lifting considered the relation between work demands and the assessment of the maximally acceptable load on an individual level. Furthermore, none of the tests met the criteria of reliability and prognostic value for musculoskeletal complaints completely. Only for the prognostic value of relative strength capacity tests concerning pushing pulling and lifting, did there appear to be limited proof for the development of musculoskeletal complaints. CONCLUSIONS: In general, for the prevention of work related health complaints, it can be suggested that more attention should be paid to: (1) the definition of specific occupational demands; (2) the assessment of specific occupational demands; and (3) the quality of tests for specific occupational demands.

Humans↗
PubMed2001

Surfactant chain length effects on the light emission of tris(2,2'-bipyridyl)ruthenium(II)/ tripropylamine electrogenerated chemiluminescence.

The effects of nonionic surfactant chain length on the properties of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)3(2+) where bpy = 2,2'-bipyridine) electrochemiluminescence (ECL) have been investigated. The electrochemistry, photophysics, and ECL of Ru(bpy)3(2+) in the presence of a series of nonionic surfactants are reported (Triton X-100, 114, 165, 405, 305, and 705-70). These surfactants differ in the number of poly(ethylene oxide) units incorporated into the surfactant molecule. The anodic oxidation of Ru(bpy)3(2+) produces ECL in the presence of tri-n-propylamine (TPrA) in aqueous surfactant solution. Increases in ECL efficiency (> or = 5-fold) and TPrA oxidation current (> or = 2-fold) have been observed in surfactant media. Slight decreases in ECL intensity are observed as the chain length of the nonionic surfactant increases. The data supports adsorption of surfactant on the electrode surface, thus facilitating TPrA and Ru(bpy)3(2+) oxidation and leading to higher ECL efficiencies.

Journal Article↗
PubMed2001

Dilation of the sinotubular junction causes aortic insufficiency after aortic valve replacement with the Toronto SPV bioprosthesis.

OBJECTIVE: This study was undertaken to examine the causes of late aortic insufficiency in patients who had aortic valve replacement with the Toronto SPV bioprosthesis (St Jude Medical, Inc, St Paul, Minn). METHODS: From 1991 to 1996, 174 patients with a mean age of 63 +/- 11 years underwent aortic valve replacement with the Toronto SPV bioprosthesis and were evaluated annually by Doppler echocardiographic studies to assess valve function. The diameters of the aortic root were retrospectively measured in all patients who had aortic insufficiency and also in a random sample of 23 patients without aortic insufficiency. The mean follow-up was 5.8 years (range 4 to 9 years). RESULTS: Aortic insufficiency greater than 1+ developed in 19 patients. The diameter of the sinotubular junction increased in these patients and did not change in those without aortic insufficiency. The ratio between the diameter of the sinotubular junction and the size of the Toronto SPV bioprosthesis increased in patients who had aortic insufficiency and did not change in those without aortic insufficiency. Both 2-way analysis of covariance and analysis by a mixed linear model demonstrated a significant difference in slopes between the patients with aortic insufficiency greater than 1+ and in those without insufficiency for the ratio of the diameter of the sinotubular junction/diameter of the Toronto SPV relationships over time (aortic insufficiency. Year; P <.001). Structural valve deterioration was observed in 5 valves, and in 4 of them the sinotubular junction of the aortic root had dilated. The freedom from structural valve deterioration was 99% +/- 1% for patients without aortic insufficiency and 82% +/- 12% for those with aortic insufficiency of more than 1+ at 8 years (P =.004). One patient had moderate aortic insufficiency without structural valve deterioration and dilation of the sinotubular junction. CONCLUSIONS: Dilation of the sinotubular junction causes aortic insufficiency after aortic valve replacement with the Toronto SPV bioprosthesis and increases the risk of structural valve deterioration. Banding the sinotubular junction may prevent dilation and enhance the durability of this valve.

Aortic Valve↗
PubMed2000

Personality characteristics of ADHD adults assessed with the Millon Clinical Multiaxial Inventory-II: evidence of four distinct subtypes.

This study compared the personality characteristics of 104 adults diagnosed with attention deficit hyperactivity disorder (ADHD). Personality features were assessed with the MCMI-II (Millon, 1987). Participants were divided into 4 groups based on the presence of persisting oppositional defiant disorder (ODD) or other comorbid diagnoses (ADHD only, ADHD-comorbid, ADHD-ODD, ADHD-ODD-comorbid). Significant differences between these groups were present for 9 of the 13 MCMI-II personality scales, resulting in 4 modal personality styles. ADHD-only adults evidenced mild histrionic traits, whereas the ADHD-comorbid group was more often avoidant and dependent in personality style. ADHD-ODD adults showed histrionic, narcissistic, aggressive-sadistic, and negativistic traits whereas the ADHD-ODD-comorbid group had a combination of avoidant, narcissistic, antisocial, aggressive-sadistic, negativistic, and self-defeating personality features. Implications for treatment are discussed.

Adult↗
PubMed2000

Shared life narratives in the work of Lou Andreas-Salomé.

The author presents a re-reading of the works of Lou Andreas-Salomé (1861-1937), one of the key figures in the early history of psychoanalysis. He focusses in particular on her biographical and autobiographical works, as well as her correspondences with Freud, Rilke and other influential people of her time, arguing that Andreas-Salomé disappears from her own works as an autonomous speaking subject, while reappearing in the works of others as a silent, tacit influence. On closer examination, a specific genre emerges from her works that has so far gone unnoticed: the shared life narrative. The author claims that Andreas-Salomé developed this genre of shared life narratives in an attempt to match her theoretical notions of narcissism to a practical communicative position that is neither subjectivistic nor objectivistic. Relating the notion of shared life narratives to the psychoanalytic discourse, new possibilities may be opened up for expanding and enlarging our knowledge of human interaction.

Communication↗
PubMed1999

Aortic valve replacement with stentless porcine aortic valve: a pioneer series.

Durability of stentless porcine aortic valves is determined by the resistance of the cusps to mechanical fatigue and reactions by the host. This study examines the role of mismatch between the size of the valve and the diameter of the sinotubular junction on durability of the valve. A custom-made stentless porcine aortic valve designed for implantation in the subcoronary position was used for aortic valve replacement in 29 patients. There were 15 men and 14 women, with a mean age of 58 years (range 26 to 72 years). In addition to aortic valve replacement, 6 patients had mitral valve surgery, 10 patients had coronary artery bypass graft, 1 patient had closure of an atrial septal defect, and 1 had concomitant aortobi-iliac bypass graft. Follow-up time extended from 10.3 to 11.5 years and was complete. The selection of size of valve implanted was based solely on the diameter of the aortic annulus. Because the diameter of the sinotubular junction plays an important role in leaflet motion and valve competence, the size of valves was compared with the diameter of the sinotubular junction of the aortic roots where they were implanted. There was one operative death and five late deaths. There were no valve-related deaths. The actuarial survival at 10 years was 76%+/-5%. There were only two transient ischemic attacks and no strokes. One patient developed endocarditis 4 years' postoperatively and was successfully treated with aortic valve re-replacement. One patient with cardiomyopathy had heart transplantation. Thus, the stentless valve was at risk of failure in 21 patients. Nine patients developed echocardiographic evidence of valve dysfunction: seven had aortic valve re-replacement and two continue to be observed because the dysfunction is not severe. The function of the stentless valve remained normal in 12 patients. Patients with bioprosthetic valve dysfunction had a sinotubular junction 3.2+/-1.3 mm larger than the size of the valve, whereas patients with normal bioprosthetic valve function had a sinotubular junction 0.8+/-1.2 mm larger than the size of the valve (P = .01). The durability of stentless porcine aortic valve implanted in the subcoronary position is affected by discrepancies in diameters between the xenograft valve and the sinotubular junction of the aortic root. Sinotubular junction greater than the size of the stentless valve probably increases mechanical stress on the cusps and causes premature valve failure.

Adult↗
PubMed1999

The Toronto SPV: hemodynamic data at 1 and 5 years' postimplantation.

The Toronto-SPV (T-SPV) bioprosthesis has been used for aortic valve replacement (AVR) since July 1991. There is no published data on its mid-term hemodynamic performance. This study compares the hemodynamic data of a consecutive series of patients at 1 and 5 years after AVR. The first 109 consecutive patients who had AVR with a T-SPV have been monitored for a minimum of 5 years and have had annual Doppler echocardiographic studies. There were 80 men and 29 women in the study; mean age was 62 years (range 34 to 80 years). Concomitant coronary artery bypass surgery was done in 35 patients. One operative and nine late deaths occurred. The mean systolic gradient across the T-SPV in all patients was 3.9+/-2.4 mm Hg at 1 year and 4.1+/-3.3 mm Hg at 5 years (P = .27). The mean aortic valve area was 2.2+/-0.6 cm2 at 1 year and 2.3+/-0.7 cm2 at 5 years (P = .43). The mean left ventricular mass index (LVMI) was 104+/-31 g/m2 at 1 year and 97+/-24 g/m2 at 5 years (P = .08). Multivariate linear regression analysis showed that preoperative coronary artery disease (P<.0001) and hypertension (P<.01) were independent predictors of higher LVMI over time. Aortic insufficiency was none/trivial in 94% of patients and mild in 6% at 1 year. At 5 years, aortic insufficiency was none/trivial in 88% of patients, mild in 10%, and moderate in 2%. The aortic leaflets remained thin and pliable in all patients as assessed by echocardiography. Most patients (85%) were in New York Heart Association functional class I. The hemodynamic performance of the T-SPV remained unchanged during the first 5 years after implantation. The LVMI continued to decrease after the first year and tended to normalize in most patients. The aortic valve remained competent, and the leaflets did not change their thickness or show evidence of calcification.

Adult↗
PubMed1998

Aortic valve replacement with stentless and stented porcine valves: a case-match study.

OBJECTIVES: To assess the potential benefits of the hemodynamic superiority of stentless valves, we conducted a case-match study among patients who underwent aortic valve replacement with two types of porcine bioprostheses: the Toronto SPV and the stented Hancock II bioprosthesis. METHODS: Preoperative clinical variables predictive of death after aortic valve replacement were determined by a stepwise logistic regression analysis in a series of 908 consecutive patients who received porcine aortic bioprostheses during a 14-year interval. Advanced age, New York Heart Association functional class IV, left ventricular ejection fraction of less than 30%, and coronary artery disease were independent predictors of death. On the basis of these four variables, 198 pairs of patients who survived aortic valve replacement with stentless and stented porcine valves were matched. The follow-up, truncated to the shortest interval for each matched pair, was 43 +/- 24 months for both groups. RESULTS: At 8 years the actuarial survival was 91% +/- 4% for the Toronto SPV group and 69% +/- 8% for the Hancock II group (p = 0.006); the freedom from cardiac-related death was 95% +/- 4% for the Toronto SPV and 81% +/- 8% for the Hancock II (p = 0.01); the freedom from any valve-related complication was 81% +/- 5% for the Toronto SPV and 50% +/- 10% for the Hancock II (p = 0.008). A Cox proportional hazard model demonstrated a significant reduction in cardiac mortality rates and valve-related morbidity in patients who received the Toronto SPV bioprosthesis. CONCLUSIONS: Although it is possible that confounding factors may have played a role in the clinical outcomes of this case-control study, the study suggests that aortic valve replacement with a stentless porcine valve enhances survival. This is believed to be due to the hemodynamic superiority of these valves.

Adult↗
PubMed1998

Aortic valve replacement with stentless porcine aortic valves: a ten-year experience.

BACKGROUND AND AIMS OF THE STUDY: It has been shown that although stentless porcine aortic valves have better hemodynamic features than stented porcine valves, their long-term durability remains unknown. This study was undertaken to examine the long-term clinical outcome of aortic valve replacement (AVR) with stentless porcine aortic valves. METHODS: Between 1987 and 1989, custom-made stentless valves were implanted in 29 patients (mean age 58 years), and between 1991 and 1997, the Toronto SPV was implanted in 213 patients (mean age 63 years). In addition to AVR, one-third of the patients had coronary artery bypass. All patients were followed up at annual intervals and underwent Doppler echocardiography. RESULTS: There were two operative and 11 late deaths (four cardiac, seven non-cardiac). The actuarial survival rate was 89 +/- 4% at nine years. There were two strokes and seven transient ischemic attacks; freedom from thromboembolic complications was 92 +/- 4% at nine years. Two patients developed infective endocarditis, one early and one late; freedom from prosthetic valve endocarditis was 98 +/- 1% at nine years. Freedom from primary tissue failure was 85 +/- 8% at nine years. Seven patients required repeat AVR, because of endocarditis (two) and aortic insufficiency (five); freedom from repeat AVR was 82 +/- 8% at nine years. Periodic hemodynamic assessment by echocardiography indicated that the mean systolic gradients across the valve decreased during the first year of implantation, the valve effective orifice increased, and valve competence remained stable. CONCLUSIONS: Stentless porcine aortic valves have provided excellent clinical results. These valves may suffer degenerative changes and fail at the same rate as stented porcine aortic valves but, because of their superior hemodynamic performance, they may enhance patients' survival by allowing complete regression of left ventricular hypertrophy and restoration of normal ventricular function.

Animals↗
PubMed1996

The registered nurse surgical assistant.

This article provides a candid account of the evolution of two Registered Nurse Surgical Assistant positions, and their roles as members of a large open-heart team. A description of the expectation of the job, the role in surgery and the challenges and rewards are outlined.

Cardiac Surgical Procedures↗
PubMed1995

Repair of the aortic valve in patients with aortic insufficiency and aortic root aneurysm.

Patients with aneurysms of the ascending aorta or aortic root frequently have aortic insufficiency despite normal aortic leaflets. The aortic valve dysfunction is caused by dilatation of the sinotubular junction, distortion or dilatation of the sinuses of Valsalva, annuloaortic ectasia, or a combination of these problems. In the case of annuloaortic ectasia, reconstruction of the aortic root is performed by reimplanting the aortic valve in a tubular Dacron graft (reimplantation). In the case of mild or no annuloaortic ectasia, reconstruction of the aortic root is performed by correcting the dilated sinotubular junction and replacement of the aortic sinuses if they are also dilated with an appropriately tailored Dacron graft (remodeling). From July 1989 to March 1994, 45 patients have had either reimplantation of the aortic valve (19 patients) or remodeling of the aortic root (26 patients). Fourteen patients had Marfan's syndrome, 11 had acute and five had chronic type A aortic dissection, and nine also had transverse arch aneurysm. There were two operative deaths, both in the remodeling group. One patient who had reimplantation needed composite replacement of the aortic valve and ascending aorta because of persistent aortic insufficiency after the repair. A young patient with Marfan's syndrome had progressive aortic valve dysfunction during a growth spurt and had aortic valve replacement 2 years after the initial operation. No other valve-related complication has occurred. The remaining 41 patients have only mild or no aortic insufficiency, and the repair remains stable from 1 to 58 months, mean 18 months. These two types of aortic valve reconstruction have provided excellent clinical results in carefully selected adult patients.

Adult↗
PubMed1994

Infective endocarditis in patients who had replacement of the aortic root.

In 12 patients who had had composite replacement of the aortic valve and ascending aorta, infective endocarditis developed 2 months to 17 years after operation. Six patients had mechanical valves and 6 had biological ones (four homograft and two porcine valves). All patients needed operation because of shock, heart failure, persistent sepsis in spite of adequate antibiotic therapy, or the development of a paravalvular false aneurysm. The predominant microorganism was Staphylococcus. All 6 patients who had mechanical valves were found to have an abscess in the junction between the aortic annulus and the prosthesis; in patients who had biological valves the infection was limited to the leaflets in 3 (one homograft and two porcine valves) and leaflets and annulus abscess in 3 (three homograft valves). Operation consisted of radical resection of tissues suspected of being infected and reconstruction of the left ventricular outflow tract and of the surrounding structures with glutaraldehyde-fixed bovine pericardium. The aortic valve and ascending aorta were replaced with a new valved conduit. An aortic homograft was used in only 1 patient. There was only one operative death due to right ventricular infarction but most patients experienced serious postoperative complications. Operative survivors were followed up from 3 to 156 months (mean, 42 months). One patient died 35 months postoperatively due to bleeding complications of anticoagulation; 1 patient suffered a cardiac arrest at home 2 months after operation, sustained permanent cerebral damage, and died 4 months later. The remaining patients are asymptomatic from the cardiovascular viewpoint.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Stentless porcine bioprosthesis for aortic valve replacement.

We report herein our experience with the Toronto Stentless Porcine Valve (Toronto SPV, manufactured by St. Jude Medical Inc., Minneapolis, MN, USA) for aortic valve replacement (AVR). To date 146 SPV valves have been implanted, 29 in an initial clinical trial (from October 1987 to April 1987) and 117 in the current FDA trial (September 1991 to January 1994). In the current trial the majority of patients were male (76%), aortic stenosis was the dominant lesion (73%) and 68% of the patients received a valve size 27 mm or greater. The mean age was 61.3 +/- 12.0 years. For the entire group there has been no hospital death and no patient has required a pacemaker. Perioperative complications were myocardial infarction in three patients and suspect subacute bacterial endocarditis (medically treated) in three patients. There have been two late deaths (2%), two patients have had transient ischemic attacks (2%), and one patient suffered stroke with complete neurological recovery (1%). To date there has been no case of primary valve failure. Echocardiographic assessment of the SPV valve has demonstrated excellent effective valve orifice areas with very low transvalvular gradients and 95% of the patients had either 0 or 1+ insufficiency. These results are encouraging and justify the continued use of this valve in clinical trials. Further follow-up is required to determine its durability.

Adult↗