Urine and serum monoclonal antibody pregnancy tests are easier to use than latex agglutination-inhibition slide tests. Their more selective binding properties allow detection of low levels of human chorionic gonadotropin (HCG) in the urine and serum. These tests approach the accuracy of serum beta-HCG radioimmunoassays for confirmation of normal pregnancy or evaluation of possible abnormal pregnancy.

Antibodies, Monoclonal↗

PubMed1987

Heterophile antibodies and the diagnosis of Rocky Mountain spotted fever.

Explore the source record for details and available documents.

Adult↗

PubMedDate not supplied

Fluid mechanics of arterial stenosis: relationship to the development of mural thrombus.

In this study, we analyzed blood flow through a model stenosis with Reynolds numbers ranging from 300 to 3,600 using both experimental and numerical methods. The jet produced at the throat was turbulent, leading to an axisymmetric region of slowly recirculating flow. For higher Reynolds numbers, this region became more disturbed and its length was reduced. The numerical predictions were confirmed by digital particle image velocimetry and used to describe the fluid dynamics mechanisms relevant to prior measurements of platelet deposition in canine blood flow (R.T. Schoephoerster et al., Atherosclerosis and Thrombosis 12:1806-1813, 1993). Actual deposition onto the wall was dependent on the wall shear stress distribution along the stenosis, increasing in areas of flow recirculation and reattachment. Platelet activation potential was analyzed under laminar and turbulent flow conditions in terms of the cumulative effect of the varying shear and elongational stresses, and the duration platelets are exposed to them along individual platelet paths. The cumulative product of shear rate and exposure time along a platelet path reached a value of 500, half the value needed for platelet activation under constant shear (J.M.. Ramstack et al., Journal of Biomechanics 12: 113-125, 1979).

Algorithms↗

PubMedDate not supplied

Vortex shedding in steady flow through a model of an arterial stenosis and its relevance to mural platelet deposition.

In this study, the development of unsteady vortical formations in the separated flow region distal to a stenosis throat is presented and compared with the platelet deposition measurements, to enhance our understanding of the mechanisms involved in platelet kinetics in flowing blood. Qualitative and quantitative flow visualization and numerical simulations were performed in a model of a streamlined axisymmetric stenosis with an area reduction of 84% at the throat of the stenosis. Measurements were performed at Reynolds numbers (Re), based on upstream diameter and average velocity, ranging from 300 to 1,800. Both the digital particle image visualization method employed and the numerical simulations were able to capture the motion of the vortices through the separated flow region. Periodic shedding of vortices began at approximately Re=375 and continued for the full range of Re studied. The locales at which these vortices are initiated, their size, and their life span, were a function of Re. The numerical simulations of turbulent flow through the stenosis model entailed a detailed depiction of the process of vortex shedding in the separated flow region downstream of the stenosis. These flow patterns were used to elucidate the mechanisms involved in blood platelet kinetics and deposition in the area in and around an arterial stenosis. The unsteady flow development in the recirculation region is hypothesized as the mechanism for observed changes in the distribution of mural platelet deposition between Re =300, 900, and 1,800, despite only a marginal variation in the size and shape of the recirculation zone under these flow conditions.

Animals↗

PubMedDate not supplied

Symptom reporting in wanted and unwanted pregnancies.

This study examined the association between unwanted pregnancy and the reporting of pregnancy symptoms in a sample of 99 pregnant women drawn from an urban, medical school based family practice residency. Of these women, 51 had unwanted pregnancies, and 48 had wanted pregnancies. Women with wanted pregnancies were more likely than women with unwanted pregnancies to report three pregnancy symptoms (amenorrhea, breast tenderness, and morning sickness). This association of symptoms with a wanted pregnancy persisted after controlling for age, race, marital status, contraceptive use, menstrual irregularity, and days since last menses through multiple logistic regression. Findings suggest that symptoms may be underreported by women with unwanted pregnancies.

Amenorrhea↗

PubMedDate not supplied

The unanticipated pregnancy: a preliminary study.

To guide clinical judgements regarding possible pregnancy in women seen for nonpregnancy concerns, 75 pregnant women tested for pregnancy confirmation were compared to 31 women with pregnancies diagnosed when tested to clarify undifferentiated symptoms. Symptom clarification patients were more often unmarried (74.2% vs 37.3%, P less than 0.001), unemployed (54.8% vs 14.7%, P less than 0.0001), uninsured (54.8% vs 25.3%, P less than 0.004), black (67.8% vs 45.3%, P less than 0.04), using contraception (45.2% vs 22.7%, P less than 0.02), and carrying unwanted gestations (77.4% vs 34.7%, P less than 0.0001). Symptom clarification patients had a median 2 pregnancy symptoms versus 3 for pregnancy confirmation patients (P less than 0.001), less often reported amenorrhea (25.8% vs 6.7%, P less than 0.01) or breast tenderness (38.7% vs 66.7%, P less than 0.01), but more often experienced abdominal pain (45.2% vs 17.3%, P less than 0.003). Thus, symptom clarification patients are often earlier in gestation with fewer pregnancy symptoms, or may differ in how they perceive and interpret such symptoms when present, findings consistent with a tentative hypothesis that symptom clarification patients may not have anticipated being pregnant.

Adult↗

PubMedDate not supplied

Closing behavior of a new bileaflet mechanical heart valve.

Recently, the in vivo cavitation potential has become a primary concern among manufacturers of new mechanical heart valves (MHV). An experimental/computational program was designed to investigate each of the flow parameters involved. It was established that the closing velocity of the leaflet holds the key to MHV cavitation. One of the novel concepts of the new bileaflet mechanical heart valve (1205-MHV) was its ability to operate with a relatively small angular excursion that led to a much smaller closure velocity at impact (as compared with control valves). This is believed to significantly reduce the cavitation potential. The 1205-MHV is characterized by a longer valve body, with the hinges protruding further upstream. The unique design allows the valve the freedom to open as much as 90 degrees. The closure velocities are reduced by a smaller leaflet excursion (50 degrees), combined with a floating hinge that allows absorption of part of the impact energy at closure. The impact velocities of the 1205-MHV leaflets at closure were measured by a laser sweeping technique that monitored the leaflet closing motion with a precision of 5 microseconds within the last 3 degrees before impact. The 27 mm 1205-MHV (the largest size) was tested in the program by mounting the valve in the mitral position of a physiologic mock circulatory loop. The valve was tested at 70, 90, and 120 bpm. The results were compared with those of a St. Jude Medical 29 mm MHV. The closure velocities measured with the 1205-MHV were significantly lower than those measured with the control valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗