Search

Since acute mountain sickness (AMS) is associated with rapid ascent and with fluid retention, we assessed clinical status and fluid homeostasis in men slowly ascending on foot over 3 d to 4559 m and remaining at this altitude 5 d. We studied 15 male mountaineers, 6 of whom had previously had repeated, severe AMS or high altitude pulmonary edema (HAPE), at 1170 m, 3611 m, and 4559 m. We found that four of the six subjects with previous AMS or HAPE compared with none of nine with no such history, developed these conditions. Those who remained well had a diuresis that could not be overcome by increasing fluid intake and no change in renin activity, plasma aldosterone, or atrial natriuretic peptide (ANP). Those who became ill showed considerable weight gain independent of fluid intake, and a great increase in ANP which correlated with measurements of right atrial cross section. We conclude that mountaineers who have previously experienced repeated AMS or HAPE get fluid retention despite slow ascent and that this is associated with widening of the atrium and an increase in ANP.

A coupling factor necessary for the photophosphorylation and Mg2+-ATPase activities in Rhodospirillum rubrum chromatophores has been separated from these particles. Although the redox potential of coupling factor deficient chromatophores is slightly more oxidized than of the control, the addition of the coupling factor for reconstitution does not alter the redox potential. Phenazine methosulfate cannot restore or significantly enhance the photophosphorylation activities of uncoupled or reconstituted chromatophores compared to the control. The coupling factor can bind to coupling factor deficient membranes without addition of magnesium ions and thus restore the photophosphorylation and Mg2+-ATPase activities of these vesicles. The Ca2+-ATPase in the coupling factor preparation shows binding characteristics similar to those of the coupling factor.

In a prospective study (238 men, mean age 53 years) the changes of the native vessels were studied 3 months after a-c-bypass operation and 5 months after preop. angiography. Progression was defined as increase of stenoses of at least 20% or new total occlusion. Progression was significantly more frequent in vessels with than without bypass and was located proximally to the anastomoses in most cases, less frequently at the anastomoses and very rarely distally to the anastomoses. Proximal progression was significantly more frequent with patent than with occluded bypasses. Stenoses at the anastomoses were significantly more frequent with occluded than with patent bypasses. Stenoses of higher degrees had a stronger tendency for progression than slighter stenoses. Regression was rare and nearly always caused by surgery.

1. Zellfreie Extrakte von Rhodopseudomonas gelatinosa fixieren CO2 in Gegenwart von Ribose-5-Phosphat, NADH, ATP und Mg2+. 2. ATP kann weitgehend durch Pyrophosphat ersetzt werden. 3. Die CO2-Fixierungsraten sind von den Wachstumsbedingungen der Zellen abhangig: photolithotroph: 13,8 nMol CO2 fixiert min−1 mg Protein−1 photoheterotroph: 9,2 nMol CO2 fixiert min−1 mg Protein−1. 4. AMP fordert in, Anwesenheit von PPi die CO2-Fixierung, wirkt aber hemmend auf die ATP-abhangige CO2 Fixierung.

Postoperative angiography was performed in 222 patients who had undergone aorto-coronary bypass grafting. Double sequential grafts show the highest patency rate (90%), followed by single (77%) and multiple (65%) sequential grafts.

In a prospective study (238 men, mean age 53 years) the changes of the native vessels were studied 3 months after a-c-bypass operation and 5 months after preop. angiography. Progression was defined as increase of stenoses of at least 20% or new total occlusion. Progression was significantly more frequent in vessels with than without bypass and was located proximally to the anastomoses in most cases, less frequently at the anastomoses and very rarely distally to the anastomoses. Proximal progression was significantly more frequent with patent than with occluded bypasses. Stenoses at the anastomoses were significantly more frequent with occluded than with patent bypasses. Stenoses of higher degrees had a stronger tendency for progression than slighter stenoses. Regression was rare and nearly always caused by surgery.

The effects of the antiaggregant substance ticlopidine and of the anticoagulant acenocoumarol on patency rates of aorto-coronary bypass grafts were compared in a prospective randomized trial. Ticlopidine, 250 mg b.i.d. was administered orally from the first postoperative day till angiography, while anticoagulation with acenocoumarol was initiated on the second to third postoperative day. Side-effects of ticlopidine were rare and patient management with the standard dosage of this drug was easier than oral anticoagulation. From an initial group of 166 randomized patients 149 completed the trial by coronary angiography three months postoperatively. The 78 patients in the ticlopidine group showed a compliance of 85%. The average prothrombin time in the 71 patients receiving acenocoumarol was 26.9%. Detailed statistical analysis of the two study groups revealed no reason to doubt the correctness of randomization. Coronary angiography showed an average patency rate per patient of 84% with ticlopidine and of 82% with acenocoumarol. This and various other measures of graft occlusion did not reveal any substantial difference in graft patency of patients receiving ticlopidine or acenocoumarol. It is concluded that ticlopidine may well be used instead of anticoagulants for prevention of postoperative occlusion of aorto-coronary bypass grafts.

Molecular biologists have recently developed the technology required to determine the genetic information of complete organisms. They are now faced with a number of interesting computational problems as they attempt to process data. We are interested in developing a software environment to support molecular biologists. As their computational problems are frequently complex and computation-intensive, we believe that such an environment must both support rapid prototyping of new algorithms and allow high performance execution on a variety of multiprocessor configurations. We believe that this can be achieved using a bilingual approach, in which the upper levels of programs are coded in a concurrent logic programming language and the lower levels in C. The concurrent language provides ease of parallel programming and portability over a range of parallel computers; C provides efficient implementation of low-level algorithms. To explore the suitability of this approach, we have investigated its use in attacking a prototypical computational problem, the problem of aligning a set of sequences of genetic material. This report introduces the algorithm used to generate alignments, outlines the techniques used to develop the bilingual program, and describes initial experiments in parallel execution of this program. 7 refs., 2 tabs.

Resumption of work after aorto-coronary bypass surgery was studied in 317 patients with a mean age of 51 years. 217 patients who underwent surgery between 1975 and 1978 were studied retrospectively (group I) and 100 patients operated upon between 1979 and 1980 prospectively (group II). A coronary control study was performed in 106 patients of group I and in all patients of group II. Age, postoperative NYHA class, and pre- and postoperative ejection fraction did not differ in the two groups. Significant differences between the two groups were found regarding preoperative NYHA class (2.9 vs 2.5), amount of diseased coronary vessels (2.3 vs 2.6), number of bypass grafts (2.4 vs 3,2, all p's less than 0.001) and graft patency rate (70 vs 80%, p less than 0.025). One year after surgery 78% in group I and 84% in group II were back at work (ns). However, among the patients not working before surgery, 54% in group I and 73% in group II had returned to work (p less than 0.005), which indicates a greater success rate for aorto-coronary bypass grafting in recent years. Best predictors for resumption of work after surgery are relief of symptoms, normal work capacity in the bicycle test, duration of inability to work before surgery and type of occupation.

A family with congenital hypofibrinogenemia (fibrinogen levels of 60-90 mg%) has been studied. Out of 19 members tested, 11 exhibit this trait, which follows a strictly autosomal-dominant pattern of inheritance. Congenital hypofibrinogenemia appears to be a separate entity which can be distinguished from heterozygous individuals of congenital afibrinogenemia and from congenital dysfibrinogenemia. A bleeding tendency of clinical significance is observed only during major surgery or after severe injury.

In a prospective study (238 men, mean age 53 years) the changes in native vessels were studied 3 months after aorto-coronary bypass operation and 5 months after preoperative angiography. Progression was defined as increase in stenoses of at least 20% or new total occlusion. Progression was significantly more frequent in vessels with bypass than without; it was located proximally to the anastomoses in most cases, less frequently at the anastomoses and very rarely distally to the anastomoses. Proximal progression was significantly more frequent with open bypasses than with occluded ones. Stenoses at the anastomoses were significantly more frequent with occluded bypasses than with open ones. More severe stenoses had a stronger tendency to progression than less severe stenoses. Regression was rare and nearly always caused by surgery.

ECG from 150 patients with clinically and radiologically established ankylosing spondylitis were compared with those from a healthy age and sex matched group. The reported frequency of atrioventricular conduction defects (3-15%) was confirmed (4.6%). These and other pathological ECG changes were also found in the control group. No significant statistical difference in frequency was found. The refore doubt remains whether the pathological changes of the ECG can be attributed to ankylosing spondylitis.

An enhanced rate of progression of coronary stenoses has been reported after aortocoronary bypass surgery [4]. It was the purpose of our study to investigate the changes of the native vessels 3 months after aortocoronary bypass operation.

This paper summarizes our investigations into the computational detection of secondary and tertiary structure of ribosomal RNA. We have developed a new automated procedure that not only identifies potential bondings of secondary and tertiary structure, but also provides the covariation evidence that supports the proposed bondings, and any counter-evidence that can be detected in the known sequences. A small number of previously unknown bondings have been detected in individual RNA molecules (16S rRNA and 7S RNA) through the use of our automated procedure. Currently, we are systematically studying mitochondrial rRNA. Our goal is to detect tertiary structure within 16S rRNA and quaternary structure between 16S and 23S rRNA. Our ultimate hope is that automated covariation analysis will contribute significantly to a refined picture of ribosome structure. Our colleagues in biology have begun experiments to test certain hypotheses suggested by an examination of our program's output. These experiments involve sequencing key portions of the 23S ribosomal RNA for species in which the known 16S ribosomal RNA exhibits variation (from the dominant pattern) at the site of a proposed bonding. The hope is that the 23S ribosomal RNA of these species will exhibit corresponding complementary variation or generalized covariation. 24 refs.