PubMed Health⌕ Search

Biomedical subjects

J Bos

Publications and source records attributed to J Bos.

At least 37 records · Page 2Linked to original sources
PubMed1994

Aortic valve replacement with a stentless porcine aortic valve. A six-year experience.

A stentless porcine aortic valve was used for aortic valve replacement in 123 patients from 1987 to 1993. The mean age of 86 men and 37 women was 61 +/- 12 years. Most patients had aortic stenosis; one-third had coronary artery disease and six had mitral valve disease. The stentless valve was secured in the subcoronary position by the same technique used for a freehand aortic valve homograft. The size of valve was based largely on the diameter of the sinotubular junction of the aortic root. The mean valve size was 26.5 mm (range 19 to 29 mm) and 87% were 25 mm or larger. Two operative deaths occurred, one the result of myocardial infarction and the other the result of infective endocarditis. Patients have been followed up from 3 to 77 months, mean 22 months. Three late deaths, none related to the valve, have occurred. The actuarial survival at 6 years was 91% +/- 4%. Four transient cerebral ischemic events have occurred, but two patients had extracranial cerebrovascular disease. One patient had endocarditis late in the postoperative period and required reoperation. All patients had Doppler echocardiographic studies before discharge from the hospital, 3 to 6 months later and annually. Only 15 patients have aortic insufficiency, trivial in 6 and mild in 9. The peak and mean systolic gradients decreased significantly during the first 3 to 6 months after implantation (p < 0.001), and the effective valve areas increased significantly during this time interval (p < 0.001). This improvement in valve hemodynamics is believed to be due to remodeling of the aortic root and regression of left ventricular hypertrophy. The results of aortic valve replacement with this stentless bioprosthesis have been excellent and justify its continued use in older patients.

Adult↗
PubMed1993

Evaluation of brachytherapy implants using the "natural" volume-dose histogram.

The "natural" volume-dose histogram as described by Anderson visualises graphically even small differences between source arrangements, making it a useful tool to compare planned and realised source configurations. In this study the histogram is applied to demonstrate that the introduction of an applicator in oral cavity implants or of iridium wire spacers used as templates in bladder implants improved the quality of the implants considerably, resulting in close agreement between the planned and the realised source configuration.

Brachytherapy↗
PubMed1993

Synthesis and potential anthelmintic activity of methyl-5-(4-salicyloyl-piperazin-1-yl)-benzimidazole-2-carbamates.

A series of methyl-5-(4-salicyloyl-piperazin-1-yl)-benzimidazole-2-carba mates (IX) has been prepared. 5-(4-Salicyloyl-piperazin-1-yl)-2-nitro anilines (VII) have been synthesized starting from 5-piperazino-2-nitro anilines and salicyloyl chlorides. Catalytic reduction of VII with Pd/C, followed by treatment with 1,3-dicarbomethoxy-S-methyl isothiourea, yielded the corresponding carbamates (IX), the anthelmintic activity of which was studied. Compound IXa significantly reduced the numbers of preadults, adults and encysted T. spiralis larvae in experimental mice.

Animals↗
PubMed1992

Aortic valve replacement with the Toronto SPV bioprosthesis.

The Toronto SPV is a Dacron covered stentless porcine aortic prosthesis used for aortic valve replacement (AVR). We implanted this valve in 53 patients with a mean age of 58 years. The predominant valve lesion was aortic stenosis in 39 patients, insufficiency in 13 and a failed bioprosthesis in one. Six patients also had mitral valve disease and 18 had coronary artery disease. There was one operative death. Patients have been followed for four to 58 months, mean 27 months. There have been two late deaths but neither one was valve related. The actuarial survival at four years was 92% +/- 5%. Two patients required reoperation for reasons other than failure of the stentless aortic valve. There have been no thromboembolic complications. No patient had had infective endocarditis. Doppler echocardiographic assessment of the stentless valve revealed excellent effective valve areas and low transvalvular gradients. A few patients developed mild aortic insufficiency after implantation of the valve, but this problem has been practically eradicated by correct sizing of the prosthesis. AVR with the Toronto SPV provides excellent functional and hemodynamic results. This bioprosthesis seems to be associated with an extremely low rate of valve related complications. These findings justify its continued use, but further follow up is needed to determine its durability.

Adult↗
PubMed1991

Lung and hearth nematodes in some Spanish mammals.

Thirteen host species belonging to the orders Rodentia, Insectivora and Carnivora from various localities in Galicia (NW Spain) were examined for heart and lung parasites. The following species were found: Parastrongylus dujardini (5.5%) in Apodemus sylvaticus, Crenosoma striatum in Erinaceus europaeus (83%), Angiostrongylus vasorum, Crenosoma vulpis and Eucoleus aerophilus in Vulpes vulpes (3, 3.46 and 0.50%, respectively), Crenosoma taiga in Putorius putorius (100%) and Crenosoma sp. in Meles meles (25%). In Crocidura russula nematode larvae were found (3.3%). Mus musculus, Rattus norvegicus, Rattus rattus, Talpa caeca, Sorex araneus, Genetta genetta and Canis lupus were not parasitized by lung or heart parasites.

Animals↗
PubMed1991

Mitral valve repair by replacement of chordae tendineae with polytetrafluoroethylene sutures.

Expanded polytetrafluoroethylene sutures have been used for replacement of diseased chordae tendineae during reconstructive procedures on the mitral valve in 43 patients. There were 28 men and 15 women whose mean age was 55 years, range 21 to 76. Three fourths of the patients were in New York Heart Association class III or IV. Replacement of primary chordae tendineae of the anterior leaflet was performed with 4-0 or 5-0 polytetrafluoroethylene sutures. A double-armed suture was passed twice through the fibrous portion of the papillary muscle head and tied down. Each arm of the suture was brought up to the free margin of the leaflet and passed through the area where the native chorda was attached. After the lengths of the two arms were adjusted, the ends were tied together on the ventricular side of the leaflet. Thirty patients had degenerative disease of the mitral valve; the incompetence was due to prolapse of the anterior leaflet in 14 patients and prolapse of the anterior and posterior leaflets in 16. Eleven patients had rheumatic mitral valve disease: four had stenosis, three had regurgitation, and four had mixed lesions. Two patients had ischemic mitral regurgitation caused by rupture of a papillary muscle head. There were no operative deaths. Patients have been followed up from 5 to 61 months, mean 13. Doppler echocardiographic studies were performed at regular intervals after the operation and revealed normal mitral valve function in most patients There were two failures that necessitated mitral valve replacement: one because of acute mitral regurgitation and the other because of hemolysis. There have been two late deaths, neither one valve related. Replacement of chordae tendineae with polytetrafluoroethylene sutures is simple and allows for reconstruction of the mitral valve in many patients who would otherwise require mitral valve replacement. Because our patients have been followed up for a limited time, the long-term results of this procedure remain unknown.

Chordae Tendineae↗
PubMed1990

RAS gene mutations in childhood acute myeloid leukemia: a Pediatric Oncology Group study.

Mutations at codon 12, 13, and 61 of the HRAS, KRAS, and NRAS genes were evaluated in 99 cases of pediatric acute myeloid leukemia (AML) using oligonucleotide hybridization to polymerase chain reacted derived products. Twenty-four mutations were identified in the NRAS gene, 13 in the KRAS gene, and none in the HRAS gene. The mutations occurred in a broad spectrum of cases, and there was no specific association of RAS gene mutations with patient subsets defined on the basis of clinical or hematologic features. These data demonstrate that RAS gene mutations are at least as common in childhood AML as in adult AML and suggest that RAS gene mutations play a role in myeloid neoplasia in both age groups.

Adolescent↗
PubMed1990

Heart valve operations in patients with active infective endocarditis.

Sixty-two consecutive patients underwent heart valve operation for active infective endocarditis. There were 42 men and 20 women whose mean age was 49 years (range, 21 to 79 years). The infection was in the aortic valve in 37 patients, the mitral valve in 18, the aortic and mitral valves in 5, and the tricuspid valve in 2. Twenty-four patients had prosthetic valve endocarditis. Staphylococcus and Streptococcus were responsible for 86% of the infections. Annular abscess was encountered in 33 patients. Complex valve procedures involving reconstruction of the left ventricular inflow or outflow tract or both were performed in 31 patients. There were three operative deaths (4.8%). Predictors of operative mortality were prosthetic valve endocarditis, preoperative shock, and annular abscess. Patients were followed for 1 month to 130 months (mean follow-up, 43 months). Only 1 patient required reoperation for persistent infection. There were ten late deaths. Most survivors (96%) are currently in New York Heart Association class I or II. The 5-year actuarial survival was 79% +/- 7%. These data demonstrate excellent results in patients with native valve endocarditis, and support the premise that patients with prosthetic valve endocarditis should have early surgical intervention.

Adult↗
PubMed1990

Aortic valve replacement with stentless porcine aortic bioprosthesis.

Twenty-nine patients were entered in a clinical trial on aortic valve replacement with a stentless glutaraldehyde-fixed porcine aortic valve. This bioprosthesis is secured to the aortic root by the same technique used for aortic valve replacement with aortic valve homografts. The functional results obtained from this operation have been most satisfactory. To assess the hemodynamic benefit of eliminating the stent of a porcine aortic valve, we matched 22 patients with a stentless porcine bioprosthesis for age, sex, body surface area, valve lesion, and bioprosthesis size to 22 patients who had aortic valve replacement with a Hancock II bioprosthesis. Mean and peak systolic gradients across the aortic bioprosthesis and effective aortic valve areas were obtained by Doppler studies. Gradients across the stentless bioprosthesis were significantly lower than gradients across the Hancock II valve for every bioprosthesis size. Effective aortic valve areas of the stentless bioprosthesis were significantly larger than the valve areas of the Hancock II valve. Our data demonstrate that the hemodynamic characteristics of a glutaraldehyde-fixed porcine aortic bioprosthesis are greatly improved when the aortic root is used as a stent for the valve. This technique of implantation is expected to enhance the durability of the bioprosthesis, because the aortic root may dampen the mechanical stress to which the leaflets are subjected during the cardiac cycle.

Adult↗
PubMed1987

Activated N-ras controls the transformed phenotype of HT1080 human fibrosarcoma cells.

To investigate whether the activated N-ras oncogene of HT1080 human fibrosarcoma cells contributes to the expression of the transformed phenotype, we have isolated flat revertants. In two independent revertant lines, an increase in chromosomal ploidy occurred without a concomitant increase in the number of copies of the N-ras transforming allele. Immunoprecipitation confirms that the level of the mutant N-ras p21 gene product in the revertants is correspondingly lower than in HT1080. Analysis of sporadic tumors derived from the revertant cells reveals an increased dosage of the transforming allele. The revertants also retransform after transfection of cloned activated ras oncogenes. These results imply direct participation of an N-ras oncogene in maintaining the transformed phenotype of a human tumor cell line.

Alleles↗
PubMed1977

An autoradiographic investigation of the subcortical visual system in chimpanzee.

Based on one adult chimpanzee monocularly injected with radioactive proline, retinofugal fibers were found to terminate bilaterally in the suprachiasmatic, pregeniculate, lateral geniculate, olivary, pretectal and lateral terminal nuclei, and the superior colliculi; the existence of a dorsal terminal nucleus of the accessory optic system is in doubt. In the ipsilateral geniculate nucleus, the fibers terminate in layers 2, 3 and 5; in the contralateral nucleus, they end in layers 1, 4 and 6. Midway through the geniculate nucleus, layers 3 and 4 split medially into two daughter layers each. In the superior colliculi, most of the retinal terminals are aggregated superficially in a band located in the stratum griseum superficiale. The contralateral band is interrupted by gaps; the ipsilateral band has fewer gaps, is slightly thicker and located more deeply. There is a limited second tier of terminals in the contralateral superficial gray.

Animals↗
PubMedDate not supplied

[Histological and morphometric studies of femurs with stable hip joint replacement. An autopsy study with special reference to factors leading to late loosening].

To gain insight into the tissue reactions leading to non-infectious loosening 25 autopsy specimens of femurs with well-fixed cemented femoral components of hip prostheses were analysed histomorphologically and morphometrically. The implant duration ranged from one month to 15 years. With the exception of some focal bone-cement contacts bone and cement were separated by a fibrohistiocytic soft tissue membrane. This membrane contained wear particles predominantly of the bone cement mantle and--less abundant--of the polyethylene cups. The amount of wear particles as well as histiocytes and necroses within the membrane statistically significantly increased with advancing time in situ. The cancellous bone adjacent to the soft tissue membrane often revealed a mainly histiocytic infiltration too, accompanied by bone remodeling in this area. The histiocytic inflammatory reaction at the bone cement interface, which is mainly caused by the accumulation of wear particles is considered to be of major importance for the non infectious late loosening of cemented prostheses.

Aged↗
PubMedDate not supplied

Work-based antipoverty programs for parents can enhance the school performance and social behavior of children.

We assess the impact of the New Hope Project, an antipoverty program tested in a random assignment experimental design, on family functioning and developmental outcomes for preschool- and school-aged children (N = 913). New Hope offered wage supplements sufficient to raise family income above the poverty threshold and subsidies for child care and health insurance to adults who worked full-time. New Hope had strong positive effects on boys' academic achievement, classroom behavior skills, positive social behavior, and problem behaviors, as reported by teachers, and on boys' own expectations for advanced education and occupational aspirations. There were not corresponding program effects for girls. The child outcomes may have resulted from a combination of the following: Children in New Hope families spent more time in formal child care programs and other structured activities away from home than did children in control families. New Hope parents were employed more, had more material resources, reported more social support, and expressed less stress and more optimism about achieving their goals than did parents in the control sample. The results suggest that an anti-poverty program that provides support for combining work and family responsibilities can have beneficial effects on the development of school-age children.

Achievement↗