Biomedical subjects

J Guarini

Publications and source records attributed to J Guarini.

4 recordsLinked to original sources

PubMed2000

Measurement of ingestion rate of Hydrobia ulvae (Pennant) on intertidal epipelic microalgae: the effect of mud snail density.

The individual mean ingestion rate of Hydrobia ulvae was measured experimentally in controlled microcosms, in the dark to avoid primary production during measurement and at constant temperature. The experimental design was based on the addition of prelabelled epipelic microalgae to microcosms in a constant proportion with unlabelled diatoms, and in such a way that algal food availability was not a limiting factor within the range of tested densities (0.3 to 4.1 snails cm(-2)). Results show that the individual mean ingestion rate decreased significantly from 26.6+/-1.1 ng Chl a snail(-1) h(-1) to 22.4+/-1.0 ng Chl a snail(-1) h(-1) between 0.7 and 3 snails cm(-2). We hypothesize that this sharp decrease (the threshold density was between 1.4 and 2.5 snails cm(-2)) may account for a density-dependent effect. We have tested this hypothesis by using a simple random walk model including basic behavioural processes such as a break in feeding activity when two individuals contact each other. The model represents quantitatively well the threshold effect, suggesting that behavioural processes have to be taken into account for estimating a global feeding activity of H. ulvae populations.

Journal Article↗

PubMed1996

Marfan's syndrome: a family affair.

Marfan's syndrome (MFS), a heritable connective tissue disorder, may result in cardiac valvular insufficiency, aortic aneurysm or dissection, dislocated lens, and musculoskeletal abnormalities. During a 20-month period (1994-96), an interdisciplinary health care team at a central Virginia medical center evaluated the histories of 112 persons from 15 different families for the presence of MFS-related traits. Seventy-five had at least one MFS-related trait, and 27 subjects underwent echocardiography to evaluate for aortic root dilatation and valvular lesions. Forty-three patients (57.3%) in the above cohort demonstrated significant cardiovascular lesions, with 20 undergoing cardiac surgery. Thirty-one patients (41.3%) were initially seen with significant ocular lesions, and 38 (50.7%) displayed orthopedic deformities. The health care team developed strategies for long-term management of persons with MFS, including antihypertensive therapy, periodic testing, risk-factor modification, genetic counseling, and surgery for appropriate patients. Proactive, consistent management of MFS families will improve long-term health outcomes for this patient population.

Adolescent↗

PubMed1996

Challenges with Takayasu's arteritis: a case study.

Takayasu's arteritis (TA) is a systemic vasculitis that involves an autoimmune-mediated transmural degeneration of the aorta and its major branches, leading to severe arterial stenoses or occlusions with subsequent cerebral, cardiopulmonary, mesenteric, renal, or limb ischemia. Patient history and physical examination, arteriography, magnetic resonance imaging, and specific laboratory tests facilitate the diagnosis of TA. Major treatments for the condition include the use of corticosteroids, cytotoxic agents, antiplatelet drugs, percutaneous transluminal angioplasty (PTA), and surgical revascularization. Major nursing interventions for TA include teaching the patient and family about the progression and treatments of TA and performing periodic patient assessments for manifestations of systemic vasculitis, alterations in tissue perfusion, and alterations in coping.

Adult↗

PubMed1974

Disk susceptibility studies with cefazolin and cephalothin.

Cefazolin and cephalothin disk susceptibility and minimal inhibitory concentration determinations were conducted on 591 clinical isolates. Cefazolin demonstrated superior activity, as shown by lower minimal inhibitory concentrations, and a greater percentage of isolates inhibited in the disk susceptibility test. The cephalothin antibiotic class disk by the standard Bauer-Kirby method failed to detect susceptibility to cefazolin in a significant percentage of Escherchia coli, Enterobacter species, and Enterococcus isolates. A separate cefazolin disk with a susceptibility cut-off point of 18 mm is recommended. An alternative to a separate cefazolin disk would be a reinterpretation of the cephalothin susceptibility disk zone diameters so that it would more adequately predict cefazolin activity.

Cephalosporins↗