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Biomedical subjects

J Naessens

Publications and source records attributed to J Naessens.

67 records · Page 4Linked to original sources
PubMed1985

Echocardiographic findings in systemic amyloidosis: spectrum of cardiac involvement and relation to survival.

One hundred thirty-two patients with biopsy-proven systemic amyloidosis underwent echocardiographic examination to define the spectrum of cardiac involvement. Echocardiographic abnormalities were then correlated with clinical variables and survival at follow-up. Patients were subgrouped by left ventricular wall thickness: Group I, mean wall thickness 12 mm or less; Group II, mean wall thickness greater than 12 mm but less than 15 mm; Group III, mean wall thickness 15 mm or greater; or Group IV, atypical features such as wall motion abnormalities or left ventricular dilation. Patients with greater wall thickness had a higher frequency of associated echocardiographic abnormalities such as left atrial enlargement or granular sparkling appearance on two-dimensional examination and, more commonly, reduced systolic function. The occurrence of clinical congestive heart failure was strongly correlated with greater wall thickness and multiple other echocardiographic abnormalities. Survival was negatively influenced both by greater wall thickness and reduced systolic function. The median survival of the entire group was 1.1 years. Echocardiographic examination is an important tool for establishing the presence of cardiac amyloid involvement and may be useful in estimating prognosis in such patients.

Aged↗
PubMed1985

De novo expression of T cell markers on Theileria parva-transformed lymphoblasts in cattle.

We describe monoclonal antibodies that detect two new membrane antigens on bovine T cells. One molecule is only expressed on activated T cells and has a m.w. of 100,000. The other antigen is a glycoprotein that is precipitated as two bands of m.w. 150,000 and 158,000 and is expressed on a subpopulation of T cells and all myeloid cells. We show that when bovine lymphocytes are transformed by the protozoan parasite Theileria parva, both antigens become expressed on the cell surface. The infected cell acquires the phenotype of a proliferating T cell, irrespective of its precursor cell phenotype.

Animals↗
PubMed1984

Is percutaneous coronary angioplasty less expensive than bypass surgery?

Percutaneous transluminal coronary angioplasty is widely considered to be an acceptable and less expensive alternative to bypass surgery in carefully selected patients. We compared expenditures related to cardiac care for 79 unselected patients undergoing coronary angioplasty with expenditures for 89 unselected patients undergoing elective coronary bypass surgery without a previous attempt at angioplasty. All the patients had single-vessel disease. The mean aggregate one-year monetary outlay was 15 per cent lower in the angioplasty group than in the bypass-surgery group. A major component of the expense of angioplasty was the treatment of restenosis in the 33 per cent of patients in this group in whom this late complication occurred. We conclude that percutaneous transluminal coronary angioplasty has potential for reducing expenditures for cardiac revascularization and that a further reduction may be obtainable when the rates of restenosis are improved.

Angioplasty, Balloon↗
PubMed1984

Analysis by flow cytometry of DNA synthesis during the life cycle of African trypanosomes.

DNA content, at different stages in the life cycle of the hemoprotozoan parasite Trypanosoma brucei, has been analysed with a fluorescence activated cell sorter. It was observed that the long slender bloodstream form stage and procyclic culture forms (analogous to the tsetse fly midgut stage) are dividing cell populations with cells in G1, S, G2 and mitosis. Short stumpy bloodstream form and metacyclic fly salivary gland form populations are composed of non-dividing parasites stabilized in G1 or G0 of the cell cycle. Haploids, possible sexual forms, were not detected. In response to transfer to a culture system which mimics the fly midgut, short stumpy bloodstream form parasites were readily able to initiate DNA synthesis and differentiate into dividing procyclic culture forms. This supports the suggested role of the short stumpy form as a transitional stage between the mammalian host and the tsetse fly vector. Analysis of early and late bloodstream populations of another salivarian trypanosome, Trypanosoma vivax, revealed a transition from dividing to stationary cell population similar to that observed with T. brucei. A hitherto unrecognized morphological form of T. vivax, analogous to the T. brucei short stumpy form, was detected. It is suggested that the long slender to short stumpy morphological transformation, long known in T. brucei, reflects a physiological transition from dividing to nondividing parasite relevant to the life cycle of all the salivarian trypanosomes.

Animals↗
PubMed1983

The quaternary Gs3 and Gs7 allotypes of the rabbit: generation of the determinants by interspecies molecular hybridization.

A number of allotypic markers of the rabbit immunoglobulins are present only on intact immunoglobulin molecules and not on the isolated heavy or light chains. Some of these markers, although determined by the kappa light chain, are limited to a single heavy chain class of Ig. They can be generated by in vitro hybridization of the kappa light chain with the appropriate heavy chain. The quaternary IgG allotypic determinants Gs3 and Gs7 which are determined respectively by the b4.1 and b4.2 allelic variants of the kappa b4 light chain can be generated not only by in vitro hybridization of these light chains with a rabbit gamma chain, but also to a certain extent by their hybridization to gamma chains derived from other species.

Animals↗
PubMed1982

Production of IgG-specific auto-anti-allotypes in b4.2-suppressed rabbits.

Rabbits were completely suppressed for kappa chain allotype b4.2, and autoantibodies against b4.1 or b4.2 could be raised in 2 out of 3 animals. The animal immunized with b4.1 produced anti-b4 and anti-Ms3, two activities which have never as yet been found together in one antiserum. Both autoantisera lacked the capacity to bind b4.2-IgM, whereas they precipitated 4.2-IgG very well. In one animal, anti-b4 IgM activity appeared after the sixth immunization, at the age of 14 months. Allotype suppression was maintained in both rabbits till the end of their lives whereas all control animals recovered within 6 months. The autoantisera which were specific for b4 IgG could not induce suppression in vivo. However, specific inhibition of b4 IgG secretion was observed in vitro.

Animals↗
PubMed1982

Rabbit heavy chain haplotypes--allotypic determinants expressed by VH-CH recombinants.

This report summarizes our current understanding of the heavy chain haplotypes found in our laboratories' rabbits. Independently derived data from several laboratories have been synthesizes into a consistent picture of the linked inheritance of allotypic markers found on the different heavy chain classes and subclasses of rabbit immunoglobulins in pedigreed rabbits, including the families of three apparent VH-CH recombinants. In one recombinant, the entire group of CH markers (C mu, C gamma, and C alpha) recombined with the set of VH. Although in the other two recombinants all CH markers may also have recombined as a group, in one of these only IgG and IgA CH genes were informative; in the other recombinant, only the IgG allotypes were informative. Some allotypic determinants found on IgM molecules ("conformational") appear only when a specific variable region allotype (VHa) is combined with a specific mu constant region allotype (C mu). New combinations of VHa and C mu allotypes were generated in two of the genetic recombinants and led to new "conformational" determinants. The gains and losses observed lend support to the hypothesis that the determinants result from conformations generated by the combination of allotype-specific VH and C mu protein sequences. Conceivably, DNA events that join VH to diversity (D)- and joining (J)-coding sequences or mRNA processing events that splice J to C mu could be involved in generating the sequences that form allotype-specific determinants.

Animals↗
PubMed1981

The structure and reliability of health belief indices.

A wealth of research using the Health Belief Model provides empirical evidence of the model's utility in predicting health, illness, and sick role behaviors. Until recently, however, little attention has been paid to the important issues of the validity and reliability of measures used to assess various health belief dimensions. Using factor analysis, our study demonstrates that moderately reliable indices covering a wide spectrum of distinct health beliefs can be constructed and then replicated across independent samples. The factor analysis approach revealed that condition-specific measures of perception of susceptibility and severity and situation-specific measures of perceived barriers are empirically distinct from general measures of these beliefs. We therefore recommend caution in mixing general and specific questionnaire items within the same index when measuring these beliefs. A factor representing perceptions of health threat emerged, but its composition require further clarification. The degree of similarity between the factor structures in the two independent samples provides support for the existence of independent health belief dimensions.

Attitude to Health↗
PubMed1980

Suppression of VH, C gamma and C mu gene products in rabbits by maternal immunization against IgM allotype and detection of somatic recombinant molecules in these animals.

Suppression of the mu-chain allotype Ms16 was obtained in young heterozygous Ms16/Ms17 rabbits by immunizing the Ms17 mother against the paternal Ms16 allotype. Examination of the concentration of the VH and CH allotypes of paternal origin (a2,Ms16 and e14) in the offspring, revealed not only Ms16 suppression but also VH and C gamma allotypic suppression. The degree of suppression for the C gamma markers (4-25-fold decrease) was much less than that for the C mu or VH markers (50-150-fold decrease). The excess C gamma marker (e14) was found to be present for the major part on molecules possessing the VH allotype derived from the homologous allelic chromosome. The pattern of persistence of molecules with the suppressed C gamma marker in the serum is consistent with the idea that these molecules arise by somatic recombination and that the gene order is VH, C mu and C gamma.

Animals↗
PubMedDate not supplied

Comparison of pathology in susceptible A/J and resistant C57BL/6J mice after infection with different sub-strains of Plasmodium chabaudi.

Susceptible A/J and more resistant C57BL/6J mice were infected with Plasmodium chabaudi chabaudi 54X, P.c. chabaudi AS and Plasmodium chabaudi adami 408XZ. As expected, most C57BL/6J mice survived the infections with the different isolates. But in contrast to previous observations, not all A/J mice succumbed to infection: just over 50% of A/J mice survived infections with P.c. chabaudi 54X, while 80% survived P.c. chabaudi AS. The more virulent parasite, P.c. adami 408XZ, was able to kill all A/J mice and 20% of C57BL/6J mice after an intravenous infection with 10(5) pRBC. A detailed study of four parameters of pathology (body weight, body temperature, blood glucose and RBC counts) in both mouse strains after a P.c. adami 408XZ infection showed similar patterns to those previously reported after infection with P.c. chabaudi AS. These data suggest that environmental factors as well as parasite polymorphisms might influence the severity of malaria between susceptible and resistant mice.

Animals↗