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Biomedical subjects

E Böhm

Publications and source records attributed to E Böhm.

At least 19 recordsLinked to original sources

What's new in exogenous osteomyelitis?

By the increase in road and occupational accidents during the past few decades posttraumatic osteomyelitis has become not only the most important type of exogenous but of all inflammatory bone processes. The major morphologic, bacteriologic and immunologic studies about posttraumatic bone inflammation will be outlined in this survey. The histologic classification of chronic osteomyelitis has proved useful for the observation of the course and for the selection of the treatment in 1,500 patients. Detailed morphological studies have shown that posttraumatic osteomyelitis often begins with a necrosis of the outer tangential lamella of the tubular bone partly promoted by partial periosteal retrogression, possibly followed by a necrosis of the fracture ends caused by a disturbance of the medullary blood circulation. Type and extent of osteomyelitis are determined by several traumatic, therapeutic and endogenous factors. Bacteriologically an infection with staphylococcus aureus is still prevailing. Comparative studies about the causative agents shortly after the trauma and during the following osteomyelitis have basically shown an identical range of causative agents. Immunologic studies with monoclonal antibodies in the actual site of inflammation have on the one hand found a decrease in the number of T-lymphocytes and the T-helper cells and on the other hand an increase in the T-suppressor cells, natural killer cells, macrophages in the osteomyelitic site. The impact of these findings on the therapy of osteomyelitis can presently not be estimated. However, they will become important after immunohistochemical studies of the bone and soft tissue Lager in osteosynthetic material after aseptic bone surgery have been carried out.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents

[Angioarchitecture of the ileum and colon in Crohn disease].

Vascular changes in resected bowels of Crohn's disease were examined angiographically, microangiographically, micro-preparatorily and histologically. The proper angioarchitecture of the small and the large bowel is being destroyed in the course of the ongoing inflammatory process. Dilated capillaries, destruction of the primary angioarchitecture and its replacement by an irregular, partially bizarre pattern of scar vessels with bundling of the unchanged Vasa recta as varying vessel diameters caused by obliterating secondary fibroses can be seen in advanced Crohn's disease. The angioarchitecture of the pseudo-polyps in Crohn's disease is characterized by an increased number of vessels, bizarrely bended vessels and a radial pattern of veins. All these vascular changes in Crohn's disease are to be seen as secondary changes due to the inflammatory reaction.

Adult

Pharmacological characteristics of the stereoisomers of carvedilol.

The racemic compound carvedilol possesses two complementary pharmacological effects, vasodilation and beta-blockade. The R- and S-enantiomers of carvedilol and the racemate were investigated with respect to the beta-blocking, vasodilating, and hypotensive actions. In agreement with results obtained with other beta-blockers, only the S-enantiomer of carvedilol exerts beta-blocking effects. In contrast, no substantial difference between the enantiomers could be seen with respect to alpha-blockade. The greater hypotensive activity of S-carvedilol may be attributed to beta-blockade, which inhibits counter-regulatory mechanisms provoked by vasodilation. From these results it is concluded that there is a rationale for using carvedilol as the racemate. Using the S-enantiomer would lead to relatively strong beta-blockade with only a weak vasodilating effect. The R-enantiomer alone would act only as a hypotensive agent without beta-blockade.

Adrenergic alpha-Antagonists

[Achilles tendon rupture. Anamnestic and morphologic studies and considerations on the etiology].

From 1. October 1985 to 31. December 1987 93 patients (82 male, 11 female) with rupture of the achillestendon were investigated by means of a questionnaire, the specimens obtained at operation were examined histologically. In two cases the operation was for a rerupture of the tendon, 7 and 8 weeks respectively after the first operation. In 6 cases a rupture followed a so-called incomplete rupture on the same side. 9 patients had had a tendonrupture of the other side between 2.5 and 10 years previously. 85.4% of the ruptures took place during a sporting activity. Of the 93 patients 55 (59%) regularly took part in long term sporting activities. Symptoms in the area of one or both achilles tendons were experienced by 32% of the patients. 80 patients with an achilles tendon rupture who were operated within 10 days demonstrated structural degeneration of at least moderate proportions, mostly severe or very severe (there was no relationship between the degree of degeneration and the age of the rupture). The signs of repair were consistent with the age of the rupture. In 56% of the ruptures up to four days old the repair process was considerably more advanced than the age of the rupture would suggest. 6 of 10 patients with the so-called "Archillodynie" demonstrated minor changes although 3 had more severe degenerative changes. Our inquiry clearly demonstrates that structural changes in the tendon took place before the injury. In the cases of achilles tendon rupture the processes of repair are an-adequate to compensate for the degenerative changes. The etiology of the structural degenerations is dependent on many endogenous and exogenous factors particularly the inadequacy of the repair processes.

Achilles Tendon

[Multiple lipomas of the colon. Case report with clinical, roentgenologic, angiographic and histologic findings].

Case report on a 26 year old woman with multiple lipomas of the colon and rectum and a neurofibromatosis simultaneously. Description and discussion of clinical data and differential diagnosis. The vascularisation of the lipomas and of the overlying mucosa was proved to be good angiographically. This is the reason for the frequent bleeding of the lipomas of the colon. The coincidence of multiple lipomas and neurofibromatosis is rare. Therefore conclusions for a possible common etiology of the two diseases should be drawn only after further reports.

Adult

[Decubitus ulcer in paraplegic patients--a comparative clinico-pathologic study].

331 pressure sores of 141 patients with paraplegia were investigated histologically, the results were partly correlated with the roentgenological features. The level of the spinal cord lesion was the segment Th12-L1 in 45%, the decubital ulcers were mostly localized above the os ischiadicum (64%). A pseudocancerosis was diagnosed in 14.2%, one time a cancer in a sacral decubitus has been found. The inflammation was limited to the soft tissue in 56.9%, in 28.5% a chronic osteomyelitis of different severity had developed. In 73.6% of the patients with a histologically proven osteomyelitis this osteomyelitis could be diagnosed roentgenologically too. The high amount and severity of the dermal and bony lesions justifies the radical surgical therapy of the pressure sores, which is practised today. Our investigations of chronic pressure sores did not point out new aspects of aetiology of pathogenesis--this is only possible by experimental models.

Adolescent

[Changes in lung function following administration of eyedrops containing timolol, metipranolol, pindolol and pilocarpine in healthy probands and patients with mild bronchial asthma].

Lung function was studied double blind and randomized in 5 patients with mild asthma bronchiale and 10 normal adults before and 30, 60 and 90 minutes after one drop of 0.5% Timolol, 0.6% Metipranolol or 0.9% NaCl in each eye. In the asthmatics bronchoconstriction was seen after both beta-receptor blocking agents, more pronounced after Timolol than after Metipranolol. There was a decrease in the forced expiratory volume in one second (FEV1.0) of 32, respectively 18%. No changes were observed in the normal subjects. In a separate study no significant changes were seen in the mean values of 10 other asthmatic subjects after 1% Pindolol, 3% Pilocarpin or 0.9% NaCl. However, in two patients FEV1.0 was reduced by 15% and 20% of the control values after applying Pindolol. In summary, not only beta-receptor-blocking agents without ISA produce a bronchoconstriction in asthmatic subjects, but also beta-blocker with ISA in individual cases.

Airway Resistance

The role of cytoplasmic (newly synthesized) dopamine for the spontaneous and electrically evoked release of dopamine and its metabolites from the isolated neurointermediate lobe of the rat pituitary gland in vitro.

Isolated rat NILs were incubated in Krebs-HEPES solution. The release of dopamine and its metabolites (DOPAC, HVA and MOPET) was determined by HPLC with electrochemical detection. The spontaneous release of the sum of metabolites was about 40 times that of dopamine. The spontaneous outflow of dopamine metabolites was unaffected after inhibition of dopamine uptake (by GBR 12921) or after pretreatment with reserpine (5 mg/kg, 12 h before the experiments), but it was reduced by 50% after preincubation with the irreversible DOPA decarboxylase inhibitor, (MFMD, 10 microM, for 10 min). The combination of pretreatment with reserpine and preincubation with MFMD resulted in an 80% inhibition of the spontaneous outflow of dopamine metabolites. Treatment with reserpine caused a 98% depletion of the dopamine tissue content, whereas 60 min after exposure to MFMD the dopamine tissue content was decreased by 40%. Electrical stimulation of the pituitary stalk (3-15 Hz, in the presence of GBR 12921) caused a frequency-dependent release of dopamine. Stimulation at 7 or 15 Hz caused also a significant release of dopamine metabolites. After pretreatment with reserpine, the release of dopamine evoked by stimulation at 15 Hz was abolished, whereas the evoked release of the metabolites was only reduced by about 55%. After MFMD, the evoked release of dopamine decreased by a percentage similar to that of dopamine tissue content, but the reduction of the evoked release of metabolites was more pronounced. In conclusion, the spontaneous release of dopamine metabolites from the dopaminergic nerve endings in the NIL largely reflects the catabolism of newly synthesized dopamine.(ABSTRACT TRUNCATED AT 250 WORDS)

3,4-Dihydroxyphenylacetic Acid

Pharmacokinetics of the thioether phospholipid analogue BM 41.440 in rats.

BM 41.440 (1-hexadecylmercapto-2-methoxymethyl-rac-glycero-3-phosphocholine) is a cytotoxic thioether phospholipid analogue that recently has entered phase I trials in cancer patients. The objective of this study was to evaluate the pharmacokinetics of this compound in female rats after administration of a single oral dose (15 mg/kg body weight [bw] ). Furthermore, BM 41.440 serum concentrations were determined under a daily oral treatment of up to 13 weeks. Blood samples were obtained via permanent catheters from the femoral arteries before and after drug administration for a total of 120 hr. Urine was collected in 24 hr-intervals for 120 hr; the volume was measured, and aliquots were stored at -20 C until analytical determination of the thioether derivative. BM 41.440 was assayed in serum and urine by means of a specific, newly developed reverse-phase high pressure liquid chromatography technique. Mean maximum serum concentrations (1.7 micrograms/ml, n = 4 animals) were attained after seven hr. A terminal half-life of ca. 27 hr was calculated from the rate constant for the terminal elimination phase (lambda z approximately 0.026/hr). The mean serum BM 41.440 concentration-time-area-under-the-curve was 52.9 mg X hr/l. The ratio of total body clearance to absorption fraction was 4.7 ml/min X kg bw. Only a small amount of the drug was found in the urine. The quantity excreted in the urine during a 24 hr-interval never exceeded 1.5% of the administered dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral

[Structural principles of hemostatic processes].

The formation of the hemostatic plug on areas of skin injury is characterized as a sequence of structure-forming processes ending in the formation of an impenetrable barrier. The morphology of this barrier is further elucidated by means of scanning- and transmission electron microscopy. Especially the fibrin coating of the injury shows a completely different formation than is deducible from the solely hemostaseologically orientated view of the formation of the hemostatic plug. These structure-forming processes are: activation of the intrinsic clotting system by means of explosion-like destruction of thrombocytes with an immediate formation of a fibrin clot within seconds after the injury. Later during the process the fibrin clot is then condensed and as a function of thrombocyte dependent retraction receives its final fibrin stabilisation and modellation towards an occluding plug. The very narrow net formation of fibrin fibers is interpreted as dependent on the destruction of thrombocyte pseudopodia using their round shape as a rail for fibrin fiber formation. Disturbances of clot formation of postmortal clots compared to vital clots are interpreted as functional thrombocytic distortions, especially of the thrombocytic energy metabolism. Extracorporal clotting of blood drops after extreme ischemia resemble fibrin structures and fibrin structure formation distortions of postmortal origin.

Animals

Pharmacological profile of carvedilol as a beta-blocking agent with vasodilating and hypotensive properties.

Carvedilol is a new beta-receptor blocking and vasodilating drug that is presently undergoing clinical trials in hypertension and coronary heart disease. In this article, the pharmacodynamic properties of carvedilol are compared with those of standard drugs. The beta-blocking activity was characterized in isolated organs and in conscious rats, rabbits, and dogs. For the beta 1-blockade in guinea pig atria, the pA10 values were 7.44 +/- 0.16 for carvedilol and 6.77 +/- 0.08 for propranolol. Carvedilol is a noncardioselective beta-blocker. The i.v. doses that inhibited the tachycardia by 50% induced by 1 microgram/kg isoprenaline were 62 micrograms/kg in dogs, 138 micrograms/kg in rabbits and 841 micrograms/kg in rats. In rabbits carvedilol was slightly more active and in rats less active than propranolol. In all models, carvedilol was much more active than labetalol or prizidilol. In contrast to propranolol, carvedilol relaxed rat aortic strips. A dose-dependent decrease in arterial blood pressure was seen in different in vivo models. The total peripheral and coronary resistance were decreased in conscious dogs. The doses required for both beta-blockade and decrease in blood pressure were in the same range. The drug was also active after oral administration. There is no hint for development of tolerance.

Adrenergic beta-Antagonists

Evaluation of the risk for drug-induced postural hypotension in an experimental model: investigations with carvedilol, prazosin, labetalol, and guanethidine.

Postural hypotension is a common side effect observed in the treatment of hypertension with various drugs. Carvedilol, a vasodilating beta-blocker, was compared with prazosin, labetalol, and guanethidine for its ability to induce orthostatic hypotension. The comparison was carried out using doses of the drugs required to lower baroreceptor reflex hypertension in anesthetized rabbits by 30 mm Hg (ED -30 mm Hg). The following doses were found in independent investigations to be equipotent in this rabbit model: ED -30 mm Hg (mg/kg i.v.): prazosin = 0.03; labetalol = 1.8; guanethidine = 0.12; carvedilol = 0.12. These doses did not markedly inhibit the orthostatic reaction in rabbits after tilting stress, so 10-fold higher doses were used and clear discrimination between the drugs was found. The orthostatic index was reduced after prazosin and labetalol by about 24%, after guanethidine by about 30%, and after carvedilol by about 13%. The 50-fold dose of carvedilol (6 mg/kg i.v.) does not lead to any greater inhibition of the orthostatic index. From these results it is concluded that a relatively lower risk of postural hypotension is to be expected after carvedilol treatment than with the other drugs presented here. Furthermore, these results do not provide any indication that carvedilol exerts its vasodilator properties via alpha-blockade.

Animals