Effects of slow ascent to 4559 M on fluid homeostasis.

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.

Structure detection through automated covariance search.

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 secondary and tertiary structural interactions, but also provides the covariation evidence that supports the proposed bondings, and any counterevidence that can be detected in the known sequences. A small number of previously unknown higher-order structural features have been detected in individual RNA molecules (16S rRNA and 7S RNA) through the use of our automated procedure. We are systematically studying mitochondrial rRNA, seeking tertiary structure within 16S rRNA and quaternary structure between 16S and 23S rRNA. To test hypotheses suggested by an examination of our program's output, our colleagues in biology are 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. Our ultimate hope is that automated covariation analysis will contribute significantly to a refined picture of ribosomal structure.

Platelet inhibitors versus anticoagulants for prevention of aorto-coronary bypass graft occlusion.

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.

[Changes in the unmodified vessels after aortocoronary bypass surgery]. / Veränderungen an den Nativgefässen nach aortokoronarer Bypassoperation.

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.

[Progression of coronary stenosis following aorto-coronary bypass surgery]. / Progression von Koronarstenosen nach aorto-koronarer Bypass-Operation.

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.

[Occupational rehabilitation following aorto-coronary bypass operations]. / Die berufliche Rehabilitation nach aorto-koronarer Bypass-Operation.

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.

[Single and sequential aorto-coronary bypass: comparison of patency rate]. / Einfacher und sequentieller aorto-koronarer Bypass: Vergleich der Durchgängigkeitsrate.

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.

[A family with hereditary hypofibrinogenemia]. / Untersuchungen bei einer Familie mit vererbter Hypofibrinogenämie.

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.

[ECG changes in spondylarthritis ankylopoietica in comparison with a healthy control group]. / Ekg-Veränderungen bei Spondylarthritis ankylopoetica im Vergleich zu einer gesunden Kontrollgruppe

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.