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The extent of absorption and the intravascular itinerary of plasma-scalpel operating gas have been investigated by monitoring the intravascular and exhaled argon partial pressures during canine hepatic surgery. The blood-gas analysis was performed continuously, using a mass spectrometer to measure dissolved argon, and, periodically, using a gas chromatograph to quantify all argon ingested, including emboli. To quantify the amount of argon lost through the pulmonary circulation, monitoring took place in the right atrium and the aorta. Experimental results show that the amount of argon absorbed at the incision site and transported through the bloodstream may increase the dissolved argon concentration in the right atrium by as much as 150%. The results also indicate that argon may be present as emboli in the bloodstream, but that argon storage in the tissues is insignificant. The argon concentration in the aorta does not noticeably increase; hence the excess argon is exhaled within one circulation through the pulmonary circuit. These observations were substantiated by the use of an ultrasonic Doppler flowmeter to check for the presence of gas emboli at various locations.

Carbon disulphide and aqueous potassium hydroxide solutions act on alkali lignin, forming very viscous mixtures from which colloidal, lignin-like materials containing sulphur and of high molecular weight may be isolated.The hypothesis is advanced that a lignin xanthate may be a step in a theoretical series of reactions culminating in the formation of the materials isolated.The presence and condition of the sulphur in the isolated product are discussed from the standpoint of this hypothesis.

The desired transfer function is expanded into factors having quadratic denominators. Each factor is identified with the set A, B, C, D of matrices of the state-space representation of a capacitively terminated two-port network that is specified by a transmission matrix T. An equivalence is obtained between the required state A matrix and the corresponding T matrix. Then, T matrix synthesis techniques that were developed specifically for use with differential operational amplifiers are applied to obtain realizations of the A matrix. By synthesizing different decompositions of the T matrix, different equivalent realizations are obtained and the problem of determining appropriate input and output access ports corresponding to the B, C and D state matrices is facilitated. A practical feature of the method is that all of the basic transfer functions can be realized with grounded amplifiers and capacitors.

Summary A spinner culture system for the growth of tissue cells in fluid suspension has been described. Actively proliferating mammalian cell suspensions, in volumes of 25 to 400 ml have been established utilizing the prototype “L” cell. Similar, although less extensive, investigations have been conducted with strain HeLa. A 300 to 400 ml “L” cell spinner culture has been continuously maintained for the last 5 months. It is suggested that the described submerged culture system provides a more quantitative tool for investigations relating to the response of the mammalian cell to infectious or pharmacologic agents.

The general 2-port RCL network is subjected to a sequence of elementary transformations, followed by a similarity transformation, to produce an active RC network which is both driving-point and transfer-equivalent to the original.

SummaryA method is described for propagation of human amnion cells (Strain FL) in Spinner-type culture vessels of volumes up to 3 liter capacity. Under these conditions, it is possible to maintain a stock culture which can supply cells for growth in roller tubes and Povitsky bottles without the necessity of a trypsinization procedure. The elimination of this dispersing procedure saves considerable time in handling of the cells. These cells after being propagated in submerged culture retain their susceptibility to type 4 adenovirus.

Operative cholangiography was routinely performed during 826 cholecystectomies carried out by one physician in a private surgical practice in rural Indiana between January 1962 and January 1973. The technique of cholangiography, which involves two injections into the gallbladder neck, avoids cystic duct cannulation and adds no more than five minutes to the operating time. Statistical data were derived from the records of 547 patients observed from one to ten years. Choledochotomy was done in 127 (23%) of these patients, yielding stones in 103 (80%) and other lesions in 19 (16%). Explorations based on abnormal roentgenographic findings yielded no stones in five patients (4% of explorations and 0.9% of roentgenograms), and stones were found in the ducts of two patients in spite of normal roentgenograms (2% and 0.4%). Totally unsuspected stones were found in nine patients (representing 7% of the duct explorations). These data are similar to those reported by others. The new technique of cholangiography via the gallbladder neck is highly recommended.

Two different types of active immittance invertor are employed, one to produce equivalent inductance from capacitance, the other to generate negative conductance from resistance, and combined in a complementary manner to form a new type of RC oscillator. Only unity-gain voltage followers are required.

Uremic pericarditis that is unresponsive to intensive hemodialysis may culminate in pericardial tamponade. This complication occurred in 15 of 179 patients in long-term hemodialysis. Echocardiography was employed in 14 of 15 patients and proved to be the single most helpful diagnostic procedure. All were managed surgically, some with generous pericardiectomy, others with "pericardial window." All patients tolerated these surgical procedures well, and there were no deaths related to the surgery. Follow-up done up to four years later demonstrated that a "pericardial window" has the same efficacy as a more extensive procedure. There have been no long-term complications.

In contrast to gas gangrene, there is confusion regarding the nature, proper classification, and virulent potential of other gasforming infections. Experience with seven cases in a brief period of time confirmed our impression that these infections are associated with high morbidity and mortality rates. Since the presence of gas results from anaerobic metabolic conditions, it is an ominous clinical sign indicating the need for immediate, radical debridement.

An equivalent circuit of the general 2-port network based on a controlled source having two independent control voltages is derived. A synthesis procedure is given in terms of the transmission-matrix parameters, and it is shown that the network may be realised with only one type of operational amplifier. The method is applied to the ideal transformer, power amplifier and gyrator.

An investigation is made into the geometrical aspect of the immittance transformation properties of the general 2-port network. Its transmission matrix is decomposed to reveal orthogonal components which represent rotation and/or reflection of the load in the v/t plane, thereby obtaining new insight into the general immittance transformation process.

The orthogonal network is introduced as a fundamental impedance-transforming element and a generalisation of the well known convertor and invertor. The transforming properties are related directly to the geometrical concepts of rotation and reflection and are exploited to give new forms of oscillator and filter.

Bei mannlichen und weiblichen Ratten des Buffalo-Stammes trat nach Verabreichung von 7,12-Dimethylbenzanthracen eine Thyroiditis auf.

A 3-port unit that satisfies the requirements of the circulator concept is realised with a differential-input operational amplifier. It provides, between two of its ports, a direct measure of reflection coefficient at the third port. One unit may be employed as a hybrid transformer; two or more units may be connected in a ring to form an n-port circulator.

A correspondence is established between a basic operational-amplifier configuration and the ideal transformer with the aid of a hypothetical model of the amplifier. Several related transformer and immittance-convertor circuits are derived. All the given configurations may be obtained by a general synthesis procedure developed in a previous paper and realised with standard earthed differential-input amplifiers.