Plastic endobronchial tubes in the management of life-threatening hemoptysis

Plastic double-lumen endobronchial tube was used to maintain the airway in a patient with massive hemoptysis and nonresectable lung cancer. This tube is superior to the previously used Carlens tube, as it can be inserted in emergency situations and does not require surgical setting. In addition, the larger internal diameter of these tubes allows better airway clearance and passage of a flexible bronchoscope. The double-lumen tube may be considered as an alternative to selective main-stem intubation.

Airway complications in patients with closed-head injuries

The neurologic deficits in the closed-head injury population present special problems when managing the airway. Many of these closed-head injury patients require long-term intubation with endotracheal tube or tracheostomy to treat their central respiratory problems and control oral and pulmonary secretions. Four hundred sixty-seven closed-head injury patients were seen over a five-year period. Seventy-two of these patients required long-term endotracheal intubation, tracheostomy, or both. A prospective study by direct endoscopic examination prior to decannulation showed 23 of these 72 patients (32%) had important laryngeal or tracheal findings. The principal abnormalities observed were vocal cord paralysis, tracheal stenosis, subglottic stenosis, glottic stenosis, and tracheomalacia. This study suggests also that severely mentally impaired patients (cognitive function II and III) should retain their tracheostomy because of the high morbidity and mortality among these patients (31%) when they are decannulated. This mortality was directly related to poor pulmonary toilet, with pneumonia and sepsis being the major causes of death. This study did not show that the use of steroids or ventilators in the initial management adversely effected airway complications.

Reactivity of fibrinogen derivatives with antisera to human fibrin D-dimer and its gamma-gamma chain remnant

Highly purified D-dimer was obtained from plasmin digest of human cross-linked fibrin. After reduction of its disulfide bonds, the gamma-gamma chain remnant, containing cross-linking site, was then isolated by ion-exchange chromatography on CM-cellulose. Antisera obtained by immunizing rabbits with D-dimer and its gamma-gamma chain remnant contained a small population of antibodies which specifically reacted with D-dimer. Thus, a specific radioimmunoassay system allowing detection and quantitation of D-dimer in the presence of fibrinogen and monomeric fragment D was made possible.

Specificity of a serum peptidase hydrolyzing thyroliberin at pyroglutamyl-histidine bone

The substrate specificity of a serum enzyme which degrades thyroliberin (less than Glu-His-Pro-NH2) into pyroglutamic acid and His-Pro-NH2 has been investigated and compared with that of the pyroglutamyl aminopeptidase from calf liver. The latter enzyme has a broad specificity, causing rapid degradation of thyroliberin, pyroglutamyl beta-naphthylamide and luliberin. In contrast, the serum enzyme causes rapid stereospecific cleavage only of the pyroglutamyl-histidine bond of thyroliberin and closely related peptides. Compounds such as less than Glu-Ala, less than Glu-His and pyroglutamyl beta-naphthylamide, which are known substrates of the pyroglutamyl aminopeptidases (such as the liver enzyme), are not substrates of the serum enzyme, and inhibit it only poorly. Pyroglutamyl-containing peptides such as luliberin and neurotensin and thyroliberin analogues such as LLD-thyroliberin, less than Glu-His-Pro-NHCH3, less than Glu-His-Pro-Gly-NH2 and less than Glu-Phe-Pro-NH2 inhibit effectively the degradation of thyroliberin by the serum enzyme, but are not hydrolyzed by this enzyme. The high specificity of the serum enzyme implies a physiological function.

Chemical structure and properties of duck and goose fibrinogen

Duck and goose fibrinogen were isolated from fresh pooled plasma by three different methods. To minimize proteolytic activity, epsilon-aminocaproic acid and trasylol were used throughout the preparation procedures. Amino acid composition of fibrinogens and carbohydrate content (hexose, hexosamine, sialic acid) as well as phosphorus were analysed. Intact preparations showed single band on SDS-polyacrylamide gel electrophoresis. After reduction and modification of the thiol groups, the material could be separated by SDS-polyacrylamide gel electrophoresis into four bands corresponding to the gamma, partially degraded A alpha, B beta and intact A alpha chain. Intact polypeptide subunits were separated by ion-exchange chromatography or preparative SDS-polyacrylamide gel electrophoresis and their amino acid compositions were determined. Evidences supporting the view that bird fibrinogen is very sensitive to proteolytic degradation and that a partial degradation of the A alpha chain takes place even when inhibitors are used in all steps of the purification procedures are presented.

Chemical Characterization of Duck And Goose Fibrinogen

Chemical composition of duck /A. platyrynchos/ and goose /A. anser/ fibrinogens as well as their polypeptide subunit structure were analyzed. Amino acid composition studies of intact fibrinogens, isolated in the presence of proteolytic inhibitors, revealed their significant similarity. However, small differences between both fibrinogens in amounts of Tyr, Ser and Hys were detectable. Some differences between duck and goose fibrinogens in carbohydrate quantity were also found. They contained sialic acid /0.71 % and 0.78 %/, hexose /0.75 % and 1.1 %/ and N-acetylhexosamine /0.59 % and 0.75 %/. Electrophoretic analysis in 9 % polyacrylamide gels of reduced duck and goose fibrinogen showed the presence of two main bands /48 000 and 54 000 daltons/. The third, thrombin-sensitive band /59 000 daltons/ was weaker stained with Coomassie blue and amido black. Electrophoresis of thrombin digests of isolated fibrinogen and plasma fibrinogen demonstrated the identity of the heaviest peptide with the intact Aα chain. The remaining, probably partially degraded Aα chain, also sensitive to thrombin action, migrated together with the Bβ chain /54 000 daltons/. These observations were confirmed by isoelectric focusing analysis. Subunit polypeptide chains of duck and goose fibrinogen were isolated by CM-cellulose chromatography. Their chemical composition was also determined.

Chemical Characterization of Duck and Goose Fibrinogen

Chemical composition of duck /A. platyrynchos/ and goose /A. anser/ fibrinogens as well as their polypeptide subunit structure were analyzed. A-mino acid composition studies of intact fibrinogens, isolated in the presence of proteolytic inhibitors, revealed their significant similarity. However, small differences between both fibrinogens in amounts of Tyr, Ser and Hys were detectable. Some differences between duck and goose fibrinogens in carbohydrate quantity were also found. They contained sialic acid /0.71 % and 0.78 %/, hexose /0.75% and 1.1 96/ and H-acetylhexosamine /0.59 % and 0.75%/. Electrophoretic analysis in 9% Polyacrylamide gels of reduced duck and goose fibrinogen showed the presence of two main bands /48 000 and 54 000 daltons/. The third, thrombin-sensitive band /59 000 daltons/ was weaker stained with Coomassie blue and amido black. Electrophoresis of thrombin digests of isolated fibrinogen and plasma fibrinogen demonstrated the identity of the heaviest peptide with the intact Aa chain. The remaining, probably partially degraded Aα chain, also sensitive to thrombin action, migrated together with the Bβ chain /54 000 daltons/. These observations were confirmed by isoelectric focusing analysis. Sub-unit polypeptide chains of duck and goose fibrinogen were isolated by CM-cellulose chromatography. Their chemical composition was also determined.

Escherichia coli stringent factor binds to ribosomes at a site different from that of elongation factor Tu or G

The binding of Escherichia coli stringent factor to ribosomes has been studied; the reaction depends on 50S and 30S ribosomal subunits and poly(U) as messenger RNA. The ribosome-stringent factor complex is formed at 5-10 mM magnesium acetate; NH4 ions are inhibitory. Binding of the stringent factor to the 70S-mRNA complex is not stimulated by uncharged tRNA. The ribosomal binding site(s) for the stringent factor does not overlap with the one known for the elongation factor Tu (EF-Tu) or G (EF-G). Ribosomes carrying either EF-Tu or EF-G are active in binding the stringent factor; however, they are inactive in synthesizing guanosine 5'-triphosphate 3'-diphosphate (pppGpp) and guanosine 5'-diphosphate 3'-diphosphate (ppGpp). The latter result is due to the blockage of the ribosomal acceptor site by the aminoacyl-tRNA and/or elongation factors. That stringent and elongation factors do not compete for identical ribosomal region(s) is supported by: (1) the reverse experiments where ribosomes charged with the stringent factor are fully active in EF-Tu or EF-G dependent functions; (2) ribosomes that lack the two ribosomal proteins L7 and L12 known to be essential for EF-Tu and EF-G functions bind the stringent factor and are active in synthesizing pppGpp and ppGpp.