Findlay implantable two-stage centrifugal pump.

The Findlay centrifugal pump is unique in its two-stage pumping mechanisms and in its complementary interrelationship of the stages to each other and to the exit system, and it forms an extremely efficient unit. The first stage is a lift force pump as an inlet. The second and major stage is a shear force pump. Twenty-six prototypes, many multiply modified, have been hand fabricated, and most have had classic pump function analyses. Six pumps have demonstrated minimal hemolysis (3.5-5 h). At modest rotation speeds, it pumps water up to 10 L/min. Forty-four acute studies in normal dogs have been performed with the Findlay pump in a ventricular assist system. Blood flows through the pump ranged from 1.2 to 4.5 L/min. The conclusion is that the Findlay pump has the ability to operate with low blood damage, performs at acceptable rotational speed with reasonable hydraulic and mechanical efficiency, and is small and implantable.

A new coaxial needle for pre-operative localization of breast abnormalities.

A new coaxial needle, containing a retractable anchoring wire with a helical tip, has been developed for purposes of mammographic and sonographic localization of non-palpable suspicious breast abnormalities before surgical excision. The helically shaped tip provides the needle with a number of potential advantages over other currently available localization needles. During in vitro comparisons with other needles quantitative and qualitative evidence was obtained to suggest that the new needle can be expected to have improved anchoring capability, be deflected less by tough fibrous tissue interfaces and be more visible sonographically. The anchoring wire can also be retracted and repositioned. Preliminary clinical experience with the needle was consistent with these expectations.

Rat surgery board.

Our microsurgery laboratory needed a number of surgical rat boards, and considering the expense of the ones already on the market, we decided to make our own. A 14 in x 10 in board was cut from a large Plexiglas sheet. Suction cups with metal hooks were used to hold the rat in place. We found this board to be less expensive and also very versatile.

A frequency-time domain signal processing system.

A digital signal processing system for time series analysis with two modes of usage--the first a rapid, hands-on exploratory method, and the second an automatic, printed, labeled graphic output method--is described. The system utilizes a Time Data 1923C system with integral PDP-11 minicomputer, and a console. Major error problems have been contained and a large-volume graphic analysis capability has been developed. Applications include (a) transpulmonary pressure-pulse relationships, (b) elucidation of the multiphasic nature of pulmonary-vein/left-atrial-pressure pulse phenomena, (c) suggestive value of transfer function phenomena as a tool to demonstrate the effect of various loading and ischemic phenomena on the left ventricle, and (d) teaching-demonstration of the techniques of digital signal processing.

Genetic differences between endotoxin-sensitive and resistant C3H mice. Intraperitoneal cell response to lipopolysaccharide and prostaglandins.

The 2 related mouse strains C3H/HeJ and C3/Han differe in their response to endotoxin. C3H/HeJ mice are endotoxin-resistant, C3H/Han mice are - like all other mice - endotoxin-sesinsitive. The uptake of fluorescent intraperitoneally injected lipopolysaccharide was similar in both mouse strains. The intraperitoneal injection of lipopolysaccharide produced a higher mobilization of neutrophil granulocytes in resistant C3H/HeJ mice than in C3H/Han mice. An opposite pattern of mobilization of neutrophil granulocytes could be observed after injection of the prostaglandins E 1, E 2, and F 1 alpha: which both mouse strains were compared, a normal mobilization was observed in C3H/Han mice. C3H/HeJ mice showed a markedly decreased mobilization. If the difference between the 2 strains resides in a single gene locus itis to be assumed that lipopolysaccharide resistance is controlled by the same gene which also effects an impaired response to neutrophil mobilization after prostaglandin application.