Search

Results suggest that in pulmonary hypertension there are significant changes in the pulmonary vascular input impedance and that these changes are compatable with a more proximal major reflecting site indicative of the obstruction of small pulmonary arteries by emboli or arteriolar narrowing. There is also evidence of increased stiffness of the proximal pulmonary artery probably as the result of the increased distending pressure. This decrease in pulmonary artery compliance has significant consequences to the heart as a significant increase in hydraulic power is associated with pulsatile flow in pulmonary hypertension. These results do not confirm the relationship of decreased pulmonary artery compliance to a histologic alteration in the vessel wall since the changes demonstrated can be explained by distension alone. (Modified author abstract)

Positive end-expiratory pressure (PEEP) has been demonstrated to improve systemic arterial oxygenation in respiratory distress secondary to interstitially edematous lung. Clinical improvements, however, may be limited by the adverse circulatory effects of PEEP impairing venous return and reducing cardiac output. In an effort to eliminate this variable experimentally, the effects of graded levels of PEEP in the isolated canine lung made edematous by venous constriction were studied. These observations suggested that the increased mean inflation pressures of PEEP do not facilitate mobilization of interstitial fluid nor improve lung mechanics and that the observed improvement in gas exchange probably relateds to inflation of previously collapsed alveoli. In clinical use, however, PEEP is applied at one level for a prolonged period of time. Therefore, to delineate the prolonged effects of static PEEP, isolated canine lungs made edematous by venous constriction were treated with various levels of PEEP and observed for four hours or until hemorrhagic deterioration occurred.

Contents: Studies of insoluble collagen of experimentally induced connective tissues of man, dog, and rat; Further studies of the glycopeptides of the matrix of experimentally induced connective tissue of the rat; Comparative studies of wound connective tissue and adjacent host connective tissue in the dog and rat; Electron microscopic studies on the effect of temperature on the molecular configuration and integrity of carp swimbladder acid-soluble tropocollagen molecules; Electron microscopic studies on the structuring and growth aspects of natural collagen fibres and reconstituting SLS fibres; Electron microscopic studies on the effects of bases on the structuring unit of collagen fibres; Electron microscopic studies on the compatibility of tropocollagen molecules of differing species of origin in the fabrication of collagen fibres in vitro.

There is no demonstrable advantage in the burn rat model to therapy consisting of a single application of liquid nitrogen to the burn wound. No significant alteration in the results was found in both the seeded and non-seeded burn controls in the mortality, eschar separation, insensible water loss, bacteriologic, histologic and biochemical studies. It was concluded therefore, that although the single application of liquid nitrogen may possibly be of some help in the clinical situation, on the basis of these laboratory studies and our clinical experience, the authors believe that the increased risk of sepsis and the possibility of further epidermal damage, particularly in the deep second degree injury, would outweigh any advantage. (Modified author abstract)

Hemoglobin Ta-Li was discovered in 1970 in one male Chinese subject during our continuing survey for hemoglobin variants among Chinese school children. The subject was born in Ta-Li, Taiwan and was of Taiwanese (Fukienese) ancestry. The brother and mother of the subject also were found to have the Hb Ta-Li; all three are heterozygotes. Chemical structure studies have now established that the structural variation in Hb Ta-Li is located in the Beta chain at Position Beta-83 where a cysteinyl residue replaces the glycine group normally present at that location. In the propositus the relative amounts of Hb Ta-Li and Hb Ao, as determined by column chromatographic separations, were 40:60, respectively., Sponsored in part by the DARPA. Pub. in Biochimica et BiophysicaActa, v243 p467-474 1971. (BBA 35926).

DDT was first synthesized by a Germ an chemist in 1874, but its insecticidal properties were not discovered until 1939, when a Swiss chemical firm (J. R. Geigy, Inc.) began to use it in the control of moths and plant lice. The U. S. Department of Agriculture tested a sample in November 1942, and found it to be effective against nearly all insects. During 1943 and the first six months of 1944, that Department conducted extensive experiments to determine how DDT could best be used against the insects which threaten the health, morale and military efficiency of our troops. During this period DDT was available only in quantities for experimentation. The large scale manufacture of this substance has been achieved during time of war only through the high priorities accorded it by the War Production Board, the Army and the Navy. In 1943, when the Department of Agriculture laboratory at Orlando, Fla., was sending its first reports on DDT to the Army and the Navy, many of the accounts were difficult to believe. There was a report of a duck swimming in a pond which had been treated with DDT for larvicidal action. The duck waddled over to a large puddle and resumed his swimming. All the larvae in the second puddle were later found to be killed. A cage full of experimental flies were unintentionally killed when DDT dust was mixed at a great distance from the cage. Laboratory technicians having traces of DDT on their hands have ruined experiments when they picked up small cages in which experimental insects were kept; all the insects were killed. It was reported that one (1) part DDT in 20,000,000 parts of water killed 100 percent of larvae; one (1) part DDT in 100,000,000 parts of water killed 40.7 percent of larvae. As reports continued to come in, it was realized that DDT could accomplish all the feats ascribed to it, and many more. The prolonged residual effectiveness of DDT against insects constitutes its main advantage over previously used insecticides.

Contents: Introduction to the symbolic shorthand system; Input to the system and the store to be searched; Searching methods and output of the system; Mechanization of the system; Compilation of monographs with the help of the symbolic shorthand system; Future applications of the system; Some operational aspects of the system; Seminar panel discussion., Report on Rutgers Series on Systems for the Intellectual Organization of Information.

The study of bone marrow as an osteogenic induction agent in mice is progressing. It has been found that in Millipore Chambers, bone marrow can form bone and induce bone outside of the chamber. This potential is low. In addition, it has been found that bone formation occurs as early as two weeks within the chamber, and that bone induction outside the chamber does not occur simultaneously, but is delayed for a period of about six weeks. Further studies are underway to establish a more efficient model to study bone marrow activity in a millipore environment. A study was designed to compare healing histologically in standardized bone defects with and without mobility and to quantitate ATP and DNA in standard healing bone defects and fractures. Histologic results showed cartilage to be related to a lack of bony continuity of the mandible. ATP levels were less in the fractures and DNA levels were less in the defects. The results suggest that cartilage present in bone fractures is related to local tissue oxidative metabolism. Further studies will be designed to increase oxygen to healing fractures to prevent delayed and nonunion healing.

Contents: Leucocyte cultures: Variables in responses and studies in burned patients; Biosynthesis and release of neurophysin; Specific inhibition of the migration of vicariously sensitized macrophages from immunologically tolerant rats; Soluble macrophage factors in delayed-type hypersensitivity; Antibody affinity and antigenic competition.

An effort was made to resolve the conflict in the literature with respect to the blood sugar and insulin response in dogs and other animals in response to shock. It was found that indeed a species difference exists. An abstract describing the findings is enclosed. In addition, a study was completed evaluating the effect of fresh versus stored blood on the lung of animals resuscitated after severe shock. A third study to determine the free fatty acid, triglyceride growth hormone and glucagon response of swine to shock was completed. Results of a fourth study comparing venous and arterial lactate are also summarized. (Author Modified Abstract)

The technique of intravenous hyperalimentation has been used to study the effects and results of total parenteral feeding on the metabolic response to surgical or accidental trauma in laboratory animals and patients. Measurements of nitrogen balance, urine and serum electrolytes, and serum and urine amino acid patterns have been evaluated under a myriad of clinical conditions with carefully controlled input of nutrients. A newly developed total intravenous technique for small laboratory animals has been used to demonstrate the beneficial effects of post-operative nutrition of the healing of colon anastomoses in protein-depleted rats. The safety of the central venous catheters used for intravenous hyperalimentation has been reaffirmed by a prospective study of infectious complications, showing less than 4 percent incidence of catheter sepsis. (Author)

Adequate volume restoration has long been known to be the primary consideration in the treatment of hemorrhagic shock. Refinements in experimental techniques in recent years has permitted more sophisticated insights into the subtlties of microcirculatory flow behavior, stimulated by the observations of many workers that it is the extent of the reduced tissue perfusion in shock which determines its deleterious effects. There are several considerations affecting the decision to use any one of several fluids for replacing blood loss. First is the capacity for expanding and maintaining intravascular volume; second is the capability for providing adequate nutritional and respiratory circulatory support; third is he tendency for favorably influencing rheological or microcirculatory flow characteristics and fourth, the logistics of cost, availability, storage characteristics and other paramedical considerations. This study was designed to permit direct comparison of four fluids commonly used for volume restoration in an experimental manner analogous to the clinical situation. Emphasis was on obtaining physiological and metabolic data, although blood was studied for rheological behavior using a newly designed couette viscometer, the MTI rheogoniometer.

A very brief summary is given of a conference and workshop on the importance of the microvascular system and the microcirculation in perfused and transplanted organs. The scientific contents were arranged in divisions entitled: (1) Microcirculation under normal conditions; (2) Pathology and pathophysiology of microcirculation; (3) Organ transplantation; and (4) Perfusion of organs.

Extensive work was conducted in studying the effects of a single infusion and of the long-term administration of various commercial, experimental and laboratory emulsions to normal dogs. On the basis of the animal toxicity studies a number of satisfactory and promising i.v. fat emulsions were found. (Author), See also AD-233 668.

Results of an experiment are briefly reviewed to determine the information retrieval efficiency of a manual specialized information system based on 700,000 documents in the fields of endocrinology, stress, mast cells, and anaphylactoid reactions. The system receives 30,000 publications annually. Detailed information is represented by symbolic shorthand statements that are filed by a rigid order-of-precedence schema called the Symbolic Shorthand System. Origins of the System, examples of codification, specimen forms used in the experiment, and a brief assessment of findings are included in the report. (Author)

Levels of serum amino acids were determined in three groups of patients: normal; patients undergroing a surgical procedure; and patients that had received thermal injuries. The method of determining serum amino acid levels is presented. Brief case histories of patients involved in the study are given. A discussion of the results obtained is contained in the report. (Author), Prepared in cooperation with Louis H. Stauss Surgical Research Lab., Richmond, Va. Dept. of Surgery.