Endocardial endothelium selectively modifies relaxation in rat papillary muscle

The selective removal of endocardial endothelium of rat left ventricular papillary muscles by 1-second immersion in 0.5% Triton X-100 showed little influence on resting tension and only a small decrease in peak isometric tension (8.3 +/- 1.4 vs 9.6 +/- 2.4 mN/mm2 at Lmax, p > 0.05) with no reduction in maximal rate of tension development (+dT/dtmax; 136 +/- 21 vs 137 +/- 18 mN/mm2/s, p > 0.05). In contrast, there was a marked increase in maximal rate of tension decline (-dT/dtmax) from 71 +/- 14 to 92 +/- 15 mN/mm2/s (p < 0.05), so that the ratio between +dT/dtmax and -dT/dtmax fell from 1.98 +/- 0.27 to 1.51 +/- 0.13 (p < 0.01). Removal of endocardial endothelium led to a significant shortening of isometric twitch contractions. Time to peak tension was abbreviated from 111 +/- 20 to 84 +/- 8 ms (p < 0.05) and the half relaxation time from 92 +/- 9 to 68 +/- 8 ms (p < 0.01). Time to +dT/dtmax was also shortened from 31 +/- 6 to 44 +/- 9 ms (p < 0.05) and time to -dT/dtmax from 90 +/- 12 to 62 +/- 10 ms (p < 0.01). These effects were not influenced by alterations in stimulation frequency or muscle length. The early onset of relaxation and abbreviated duration of relaxation together with an increased rate of decline in tension led to a shorter total twitch which may explain the slightly lower peak tension once the endocardial endothelium was removed. Our findings confirm that endocardial endothelium modulates myocardial contraction, with a predominant influence on relaxation.     

Pharmacokinetics and retrograde colonic spread of budesonide enemas in patients with distal ulcerative colitis

METHODS: The retrograde spread of two budesonide enema formulations with different viscosities was investigated. The study design was open, randomized and two-period crossover. Three female and two male patients (age range: 35-45 years) with distal ulcerative colitis or proctitis participated. Both enema formulations contained a dose of 2 mg budesonide/100 mL. An unabsorbable radioactive marker (99mTc-labelled human serum albumin microcolloid) was added to the enema just before administration. All doses were given in the evening with the patients lying in a supine position during the whole investigation. The intestinal spread was followed for 8 h using scintigraphic imaging. Plasma samples for budesonide assay were taken during the 12 h after administration of the low viscosity enema. RESULTS: Budesonide plasma levels were measurable for up to 4-6 h. Cmax was 2.5 nmol/L (range: 0.9-4.5 nmol/L) and was attained in 1.5 h (range 1-3 h). The patients had no difficulty in retaining the enemas. There was a statistically significant difference in spread between the low and high viscosity enema. The low viscosity enema spread over an area situated between the rectum and the splenic flexure. The spread occurred mainly in the first 15 min after administration. In contrast, the high viscosity enema, in most cases, spread only over a minor part of this area and the rate and extent of spreading was also more variable with this formulation. CONCLUSION: The spread of a low viscosity enema appears to be well suited for the treatment of proctitis and distal colitis.     

Vascular injury during lumbar disc surgery. Report of two cases; a review of the literature

Iatrogenic vascular injuries are unusual complications of lumbar disc surgery. The incidence of such injuries is very low but probably underestimated because clinical manifestations may be extremely variable depending on the extension of trauma. Diagnosis is suspected when early signs of retroperitoneal haemorrhage appear, but may often be delayed for weeks or years due to formation of a pseudoaneurysm or an arteriovenous fistula which may be of gradual onset and produce initially only a few symptoms. Prompt diagnosis and aggressive treatment can improve the current mortality rate of more than 50%. Two cases are described that illustrate the full spectrum of acute and chronic manifestations of such injuries. One case of acute haemorrhage due to arterial trauma was immediately detected and the other case with arteriovenous fistula was recognized several years post-operatively.