A non-contact Vital Signs Monitor

The expansion and contraction of the lungs and heart result in movement of the chest wall that can be detected and monitored to determine respiration and heart rate. A prototype noncontact Vital Signs Monitor (VSM) has been developed which uses very low power, high frequency Doppler radar to detect these motions. Digital signal processing (DSP) techniques, imbedded in the VSM, are used to extract heart and respiration rate information from the resultant waveform. A 10-GHz prototype VSM was developed for the Air Force in the mid-1980s using analog technology. The objective was to assess a fallen soldier's clinical condition at distances up to 100 meters before committing resources to assist that individual. An updated and improved version of the original VSM was developed in 1997. This device was designed to operate at shorter distances, use a higher frequency carrier, and provide more specific heart and respiration rate information using digital signal prdcessing techniques. The VSM radar system is a straightforward homodyne receiver. It operates using frequency modulated continuous wave (FM-CW) transmission, which allows for very low power levels. The safe human power density exposure level at its operating frequency of 35 GHz is 10 mW/cm2. A simple approximation using uniform distribution and an antenna aperture of 2 cm by 3 cm gives a power density at the antenna face of 0.017 mW/cm2, nearly a factor of 1000 below the safe level. When the VSM's antenna is trained on the chest wall of a subject, the VSM is capable of measuring and distinguishing minute movements resulting from the mechanical activity of the heart and lungs. As the subject's chest wall moves, the exact phase of the return signal changes. To avoid the possibility of phase-related dead spots, two signals differing in phase by 90 degrees are used to demodulate the signal to baseband (DC). The two resulting 'time-varying DC' signals represent the sine and cosine of a phase angle corresponding to the changing position of the target, in this case the motion of the chest wall. The current VSM operates at a frequency of 35 GHz with a corresponding wavelength of only 8.6 mm. This provides a response sensitive enough to detect the small motions caused by cardiac function. The Vital Signs Monitor has several possible application areas. The fact that it is noncontacting would make it especially attractive for monitoring patients in burn units, NICUs, or trauma centers, where attaching electrodes is either inconvenient or not feasible. Results to date indicate a strong correlation between the cardiac component of the motion signal and an electrocardiogram (ECG). With careful signal processing and analysis, it may be possible to extract clinically useful information about cardiac condition, function, or performance from the surface-motion waveform. This could provide a safe, inexpensive, and painless addition to the diagnostic and monitoring tools currently available to cardiologists. Although there are technical obstacles to overcome in filtering gross motions of the subject, the VSM offers significant advances over conventional methods of measuring heart and respiration rate. | In the mid-1980s, a 10-GHz prototype Vital Signs Monitor (VSM) was developed using analog technology to assess a fallen soldier's clinical condition at distances up to 100 meters before committing resources to assist that individual. An updated and improved version of the original VSM was developed in 1997. This device was designed to operate at shorter distances, use a higher frequency carrier, and provide more specific heart and respiration rate information using digital signal processing techniques.link_to_subscribed_fulltex

Evaluation of a Cooperia oncophora double-domain ASP-based vaccine against Cooperia spp. infections in cattle and sheep

A double-domain activation-associated secreted protein (dd-Co-ASP) isolated from the bovine small intestinal parasite Cooperia oncophora was previously shown to be an effective vaccine candidate to protect calves against a homologous challenge infection. The aim of this study was to investigate whether the dd-Co-ASP protein, purified from a Belgian C. oncophora isolate, would offer protection against a C. oncophora isolate from the southern hemisphere as well as other Cooperia species such as C. punctata in cattle and C. curticei in sheep. Two vaccination studies were performed, i.e. one in cattle and one in sheep, in which the protective effects of dd-Co-ASP, supplemented with Quil A as an adjuvant, were compared with an adjuvant control. Whereas our results showed a 75 % reduction in Cooperia spp. cumulative faecal egg counts, the results obtained in sheep demonstrated that dd-Co-ASP was ineffective in raising a protective immune response against a C. curticei challenge infection. Even though sequence analysis of the dd-Co-ASP gene revealed restricted sequence heterogeneity in the double domain ASP within and between bovine Cooperia species, the results of the vaccine study suggest that there is sufficient conservation at the protein level to yield cross-protection, holding promise for the development of a general Cooperia vaccine for use in cattle

Plant-based production of a protective vaccine antigen against the bovine parasitic nematode Ostertagia ostertagi

Abstract The development of effective recombinant vaccines against parasitic nematodes has been challenging and so far mostly unsuccessful. This has also been the case for Ostertagia ostertagi, an economically important abomasal nematode in cattle, applying recombinant versions of the protective native activation-associated secreted proteins (ASP). To gain insight in key elements required to trigger a protective immune response, the protein structure and N-glycosylation of the native ASP and a non-protective Pichia pastoris recombinant ASP were compared. Both antigens had a highly comparable protein structure, but different N-glycan composition. After mimicking the native ASP N-glycosylation via the expression in Nicotiana benthamiana plants, immunisation of calves with these plant-produced recombinants resulted in a significant reduction of 39% in parasite egg output, comparable to the protective efficacy of the native antigen. This study provides a valuable workflow for the development of recombinant vaccines against other parasitic nematodes