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Biomedical subjects

J Howard

Publications and source records attributed to J Howard.

At least 127 records · Page 7Linked to original sources
PubMed1995

Detection of feline immunodeficiency virus in semen from seropositive domestic cats (Felis catus).

Electroejaculates from experimentally infected domestic cats were evaluated for the presence of feline immunodeficiency virus (FIV). Virus was isolated from cell-free seminal plasma and seminal cells by cocultivation with a feline interleukin-2-dependent CD4+ T-cell line, in which productive infection was demonstrated by syncytium formation and FIV gag p26 antigen secretion. In addition, an 868-bp segment of the FIV gag provirus gene was identified in cocultured cells by PCR and Southern analysis. A 582-bp fragment of the FIV gag provirus genome was detected by nested PCR and Southern analysis in nonfractionated seminal cells and in sperm purified by a swim-up procedure. This is the first report describing the detection of replication-competent FIV in cell-free and cell-associated forms in domestic cat semen.

Animals↗
PubMed1995

Alcohol-problem prevention research policy: the need for a phases research model.

This paper describes the need and rationale for developing a phases model for guiding alcohol-problem prevention research. A phased approach to prevention research is consistent with such models developed for other health areas including heart disease, cancer, and drug testing. Such a model in alcohol prevention research can provide a means for (1) locating how far research has progressed along a continuum from basic or pre-intervention research to full implementation of preventive action, (2) identifying gaps in research, and (3) determining the level of empirical proof which exists for one or more prevention strategies prior to widespread dissemination.

Alcoholism↗
PubMed1995

The mechanics of force generation by kinesin.

Several laboratories have developed highly sensitive mechanical techniques for studying the movement of purified motor proteins along their associated filaments. The aim of these experiments is to test models for force generation, such as the powerstroke model and "ratchet" or diffusional models, by 1) directly visualizing the path on the filament along which the motor moves, 2) measuring the force exerted by the motor against the filament, and 3) characterizing the passive mechanical properties (elasticity) of the motor. This paper focuses on recently published work on the microtubule-based motor kinesin taking this mechanical approach. Related work on myosin is mentioned for comparison.

Adenosine Triphosphate↗
PubMed1994

General concepts in the morphologic assessment of operatively excised cardiac valves--Part I.

This two-part article discusses the general morphologic assessment of operatively excised cardiac valves and applies these principles to functional classifications. All cardiac valves are categorized into stenotic and purely regurgitant (no element of stenosis) groups based upon structural features: presence or absence of commissural fusion, calcific deposits, and degree and location of fibrosis. Of 2980 operatively excised cardiac valves reviewed between 1962 and 1992, the most common lesion was aortic stenosis, followed by mitral stenosis and the combination of aortic and mitral stenosis.

Heart Valve Diseases↗
PubMed1994

Pathology of aortic valve stenosis and pure aortic regurgitation. A clinical morphologic assessment--Part I.

This two-part article examines the histologic and morphologic basis for stenotic and purely regurgitant aortic valves. Part I discusses stenotic aortic valves and Part II will discuss causes of purely regurgitant aortic valves. In over 95% of stenotic aortic valves, the etiology is one of three types: congenital (primarily bicuspid), degenerative, or rheumatic. Other rare causes of stenotic aortic valves include active infective endocarditis, homozygous type II hyperlipoproteinemia, and systemic lupus erythematosis. The causes of pure aortic regurgitation are multiple but can be separated into diseases affecting the valve (normal aorta) (infective endocarditis, congenital bicuspid, rheumatic, floppy), diseases affecting the walls of aorta (normal valve) (syphilis, Marfan's, dissection), disease affecting both aorta and valve (abnormal aorta, abnormal valve) (ankylosing spondylitis), and diseases affecting neither aorta nor valve (normal aorta, normal valve) (ventricular septal defect, systemic hypertension). Diseases affecting the aortic valve alone are the most common subgroup of conditions producing pure aortic valve regurgitation.

Adolescent↗
PubMed1994

Pathology of aortic valve stenosis and pure aortic regurgitation: a clinical morphologic assessment--Part II.

This two-part article examines the histologic and morphologic basis for stenotic and purely regurgitant aortic valves. Part I discussed stenotic aortic valves and Part II discusses causes of purely regurgitant aortic valves. In over 95% of stenotic aortic valves, the etiology is one of three types: congenital (primarily bicuspid), degenerative, and rheumatic. Other rare causes included active infective endocarditis, homozygous type II hyperlipoproteinemia, and systemic lupus erythematosis. The causes of pure aortic regurgitation are multiple but can be separated into diseases affecting the valve (normal aorta) (infective endocarditis, congenital bicuspid, rheumatic, floppy), diseases affecting the walls of aorta (normal valve) (syphilis, Marfan's dissection), disease affecting both aorta and valve (abnormal aorta, abnormal valve) (ankylosing spondylitis), and disease affecting neither aorta nor valve (normal aorta, normal valve) (ventricular septal defect, systemic hypertension). Diseases affecting the aortic valve alone are the most common subgroup of conditions producing purely regurgitant aortic valves.

Aortic Diseases↗
PubMed1994

General concepts in the morphologic assessment of operatively excised cardiac valves--Part II.

This 2-part article discusses general morphologic assessment of operatively excised cardiac valves and applies these principles to functional classifications. All cardiac valves are categorized into stenotic and purely regurgitant (no element of stenosis) groups based upon structural features: presence or absence of commissural fusion, calcific deposits, and degree and location of fibrosis. Of 2,980 operatively excised cardiac valves reviewed between 1962 and 1992, the most common lesion was aortic stenosis, followed by mitral stenosis and the combination of aortic and mitral stenosis.

Aortic Valve Insufficiency↗
PubMed1994

Pathology of mitral valve stenosis and pure mitral regurgitation--Part I.

This two-part article examines the histologic and morphologic basis for stenotic and purely regurgitant mitral valves. In Part I, conditions producing mitral valve stenosis are reviewed. In over 99% of stenotic mitral valves, the etiology is rheumatic disease. Other rare causes of mitral stenosis include congenital malformed valves, active infective endocarditis, massive annular calcium, and metabolic or enzymatic abnormalities. In Part II, conditions producing pure mitral regurgitation will be discussed. In contrast to the few causes of mitral stenosis, the causes of pure (no element of stenosis) mitral regurgitation are multiple. Some of the conditions producing pure regurgitation include floppy mitral valves, infective endocarditis, papillary muscle dysfunction, rheumatic disease, and ruptured chordae tendinae.

Calcinosis↗
PubMed1994

Pathology of mitral valve stenosis and pure mitral regurgitation--Part II.

This two-part article examines the histologic and morphologic basis for stenotic and purely regurgitant mitral valves. In Part I, conditions producing mitral valve stenosis were reviewed. In over 99% of stenotic mitral valves, the etiology is rheumatic disease. Other rare causes of mitral stenosis include congenitally malformed valves, active infective endocarditis, massive annular calcium, and metabolic or enzymatic abnormalities. In Part II, conditions producing pure mitral regurgitation are discussed. In contrast to the few causes of mitral stenosis, the causes of pure (no element of stenosis) mitral regurgitation are multiple. Some of the conditions producing pure regurgitation include floppy mitral valves, infective endocarditis, papillary muscle dysfunction, rheumatic disease, and ruptured chordae tendineae.

Cardiomyopathies↗
PubMed1994

Curriculum evaluation--a new approach.

This paper describes the development of a College-wide curriculum evaluation strategy. The strategy has been implemented on all courses offered by the Lancashire College of Nursing and Health Studies. An extensive review of the literature revealed that no evaluation models were suitable for use across all College courses. This was due to their over-emphasis on either the process, or the product of education; none of the published evaluation models adequately address both of these components of professional learning. The criteria required, of both the model and the evaluation tools, included the need for a measurable component, inclusiveness, simplicity and practicality. In order to meet these a new model of evaluation and appropriate data collection tools/analytical systems were developed. This Professional Process and Product Model forms the basis for the described strategy. The model is easy to use due to its recognition of the professional nature of those involved in nurse education, this professional status, and the accountability which it implies, ensures that only relevant and significant information is included in the formal evaluation of courses. This ensures an ability to meet future contractual quality standards which will be a requirement for providers in the health care of the 1990s.

Curriculum↗
PubMed1994

Organelle transport and sorting in axons.

Recent advances of the past year in the field of organelle transport have documented the existence of numerous kinesin-related proteins and the presence of multiple conventional kinesins within neurons. Biochemical and genetic mutant analyses indicate that different kinesin superfamily members transport different organelles. In addition to microtubule-based systems, actin filaments and myosin motors are associated with organelle transport in axons. The great diversity of motor proteins suggests that they may play a role in sorting, in addition to transport.

Actins↗
PubMed1994

The force exerted by a single kinesin molecule against a viscous load.

Kinesin is a motor protein that uses the energy derived from the hydrolysis of ATP to power the transport of organelles along microtubules. To probe the mechanism of this chemical-to-mechanical energy transduction reaction, the movement of microtubules across glass surfaces coated with kinesin was perturbed by raising the viscosity of the buffer solution. When the viscosity of the solution used in the low density motility assay was increased approximately 100-fold through addition of polysaccharides and polypeptides, the longer microtubules, which experienced a larger drag force from the fluid, moved more slowly than the shorter ones. The speed of movement of a microtubule depended linearly on the drag force loading the motor. At the lowest kinesin density, where dilution experiments indicated that the movement was caused by a single kinesin molecule, extrapolation of the linear relationship yielded a maximum time-averaged drag force of 4.2 +/- 0.5 pN per motor (mean +/- experimental SE). The magnitude of the force argues against one type of "ratchet" model in which the motor is hypothesized to rectify the diffusion of the microtubule; at high viscosity, diffusion is too slow to account for the observed speeds. On the other hand, our data are consistent with models in which force is a consequence of strain developed in an elastic element within the motor; these models include a different "ratchet" model (of the type proposed by A. F. Huxley in 1957) as well as "power-stroke" models.

Adenosine Triphosphate↗
PubMed1994

Young offender drug use: knowledge and perceptions of Juvenile Justice Centre youth workers.

Juvenile Justice Centre youth workers in New South Wales (n = 106) were surveyed by questionnaire as to their knowledge and perceptions of alcohol and other drug issues of those in their care. Some background variables were also collected. About 30% of the sample reported having (had) a problem with alcohol and/or other drugs and approximately the same percentage came from families with such a problem. Over 50% had received some form of drug education. There was an overestimation of the level of use of narcotics, sedative/hypnotics, anti-anxiety agents and hallucinogens of the youth workers and an underestimation of the level of use of analgesics, alcohol, cannabis and inhalants. Peer pressure was perceived as central in the initiation of use and "denial" in not gaining assistance; the style and belief systems of agencies were not seen as crucial in retaining young people in treatment. Youth workers, who are not required to have any specific education or training prior to employment, did not see themselves as well equipped to assist drug-affected or detoxifying detainees and requested more training/education. It is recommended that this could be provided through tertiary courses and/or in-service staff development.

Journal Article↗
PubMed1994

Gastrointestinal upsets associated with ingestion of copper-contaminated water.

During 1992 and 1993 the Wisconsin Division of Health investigated five cases in which copper-contaminated drinking water was suspected of causing gastrointestinal upsets. Each of these case studies was conducted after our office was notified of high copper levels in drinking water or notified of unexplained illnesses. Our findings suggest that drinking water that contains copper at levels above the federal action limit of 1.3 mg/l may be a relatively common cause of diarrhea, abdominal cramps, and nausea. These symptoms occurred most frequently in infants and young children and among resident of newly constructed or renovated homes.

Adult↗