Biomedical subjects

B Messmer

Publications and source records attributed to B Messmer.

At least 19 recordsLinked to original sources

PubMed1998

Results of the Bruce treadmill test in children after arterial switch operation for simple transposition of the great arteries.

Children who underwent arterial switch operation for simple transposition of the great arteries in the neonatal period are now reaching an age when exercise testing becomes feasible. This study was conducted to assess exercise tolerance and electrocardiographic response to exercise stress in 50 asymptomatic children, aged 4 to 9 years, using the Bruce walking treadmill protocol to voluntary exhaustion. Heart rate and blood pressure response to exercise stress, endurance time, and electrocardiographic changes were analyzed and compared with those of age-matched normal children. Forty-seven patients had normal exercise capacity and parameters. One patient, whose coronary angiogram showed occlusion of the left main coronary artery, developed electrocardiographic signs of myocardial ischemia during exercise. In 1 patient with a single right coronary artery ostium and in another, who underwent a neonatal internal mammary bypass graft for obstruction of the right coronary artery, the resting electrocardiogram showed ventricular premature complexes and exercise stress-induced salvos of ventricular tachycardia. We conclude that most of the children who underwent the neonatal arterial switch operation for simple transposition of the great arteries have a normal exercise capacity. Exercise testing appears to be useful in detecting ischemic damage or exercise-induced arrhythmias possibly secondary to reduced coronary flow reserve.

Age Factors↗

PubMed1995

[Therapy of an abdominal aortic aneurysm using transfemoral endovascular implantation of a bifurcation prosthesis].

Transfemoral intraluminal placement of a woven-dacron bifurcation prosthesis was undertaken to bridge an infrarenal aortic aneurysm (4.6 cm diameter) in a 65-year-old man with chronic coronary heart disease. The Chuter-Gianturco introducing system was used via the right femoral artery to anchor the prosthesis immediately below the origins of the renal arteries. After fixing the right branch of the prosthesis the left one was secured via the left femoral artery. No leakage was demonstrated on the 7th post-operative day and the aneurysm was satisfactorily bridged. Regular follow-up tests showed a normal circulation. Spiral computed tomography after 18 months confirmed complete thrombosis of the aneurysm.--This case shows that the described method is a promising alternative in the treatment of abdominal aneurysm.

Aged↗

PubMed1993

Regulation of canine gallbladder motility by brain peptides.

BACKGROUND: Brain peptides alter most gastrointestinal functions, but their effects on gallbladder motility have not been examined in detail. METHODS: Studies were conducted in awake, male beagle dogs. RESULTS: Of 30 brain peptides evaluated, thyrotropin-releasing hormone (TRH) and calcitonin gene-related peptide (CGRP) inhibited CCK- and meal-induced gallbladder contraction. These responses were abolished by ganglionic blockade. Truncal vagotomy prevented the central inhibitory action of TRH but not that of CGRP, whereas noradrenergic blockade prevented the central inhibitory action of CGRP but not that of TRH. Muscarinic blockade did not prevent the relaxing effect of cerebral TRH but pretreatment with the vasoactive intestinal peptide (VIP) antagonist, (4Cl-D-Phe6-Leu17)VIP, significantly attenuated gallbladder relaxation induced by cerebral TRH: the combination of both VIP and muscarinic antagonists abolished TRH-induced gallbladder relaxation. alpha-Adrenergic receptor blockade but neither beta-adrenergic blockade nor adrenalectomy abolished gallbladder relaxation induced by cerebral CGRP. Intravenous infusion of VIP and norepinephrine inhibited CCK-induced gallbladder contraction and these responses were abolished dose dependently by intravenous infusion of (4Cl-D-Phe6-Leu17)VIP and phentolamine, respectively. CONCLUSIONS: Cerebral TRH inhibits canine gallbladder contraction by stimulation of vagal outflow and subsequent release of VIP acting via its specific receptor whereas cerebral CGRP inhibits gallbladder contraction by stimulation of sympathetic, noradrenergic outflow via alpha-adrenergic receptors.

Amino Acid Sequence↗

PubMed1993

Regulation of exocrine pancreatic secretion by cerebral TRH and CGRP: role of VIP, muscarinic, and adrenergic pathways.

The central nervous system effects of thyrotropin-releasing hormone (TRH) and calcitonin gene-related peptide (CGRP) on exocrine pancreatic secretion were studied in freely moving rats. TRH (0.05-0.5 nmol) significantly stimulated, whereas CGRP (0.1-1.0 nmol) significantly inhibited, volume, protein, and bicarbonate secretion. Pretreatment of the animals with the ganglionic blocking agent chlorisondamine abolished the pancreatic responses produced by both peptides. In contrast, vagotomy abolished the stimulatory effect of TRH, whereas noradrenergic blockade with bretylium or phentolamine abolished the inhibitory effect of CGRP. Atropine significantly attenuated, but the vasoactive intestinal peptide (VIP) antagonist [D-p-Cl-Phe6, Leu17]VIP completely abolished the stimulatory effect of TRH. Pancreatic secretory responses stimulated by cerebral TRH or by peripheral VIP were inhibited dose dependently by peripheral [D-p-Cl-Phe6,Leu17]VIP. Inhibition of pancreatic secretion induced by cerebral CGRP or by peripheral norepinephrine was prevented by intravenous phentolamine. These results indicate 1) cerebral TRH stimulates and cerebral CGRP inhibits exocrine pancreatic secretion in freely moving rats; 2) the effects of TRH are mediated by vagal efferents, and the primary peripheral transmitter appears to be VIP acting on VIP receptors, whereas muscarinic efferents are less important; and 3) the effects of CGRP are mediated by sympathetic noradrenergic efferents via alpha-adrenergic receptors.

Animals↗

PubMed1993

Requirements for nuclear translocation and nucleolar accumulation of nucleolin of Xenopus laevis.

The intracellular localization of germinal vesicle proteins is regulated during early Xenopus development. Here we have analyzed the determinants that control the localization of nucleolin, a nucleolar protein of vertebrates. Our immunological analyses and isolation of cDNAs have revealed the presence of a second nucleolin gene in addition to that previously identified. The two nucleolin polypeptides of 95 kDa and 90 kDa molecular mass are both expressed in oocytes and are found predominantly in the nucleoli. During oocyte maturation, both polypeptides are hyperphosphorylated and found distributed throughout the cytoplasm. Hyperphosphorylated forms and cytoplasmic localization of nucleolin both prevail in early embryos up to the midblastula transition. Subsequently, the proteins are found in the nuclei. Accumulation in nucleoli is only detected at later stages, beginning with gastrulation. Thus nucleolar localization is temporally uncoupled from nuclear translocation. Consistent with these observations, our molecular analyses have revealed that the nuclear location signal which is present in nucleolin and which is sufficient for nuclear location, is not sufficient for nucleolar accumulation. Nucleolar accumulation requires, in addition to the nuclear location signal, the presence of the RNA binding domains and of an RG-rich domain, which is also thought to interact with RNA.

Amino Acid Sequence↗

PubMed1992

Noradrenergic inhibition of canine gallbladder contraction and murine pancreatic secretion during stress by corticotropin-releasing factor.

Gastrointestinal secretory and motor responses are profoundly altered during stress; but the effects of stress and its mediator(s) on the two major gut functions, exocrine pancreatic secretion and gallbladder motility, are unknown. We therefore developed two animal models that allowed us to examine the effects of acoustic stress on canine gallbladder contraction and restraint stress on rat exocrine pancreatic secretion. Acoustic stress inhibited cholecystokinin-8 (CCK)- and meal-induced gallbladder contraction, and restraint stress inhibited basal and CCK/secretin-stimulated pancreatic secretion. These inhibitory responses were mimicked by cerebral injection of corticotropin-releasing factor (CRF) and abolished by the CRF antagonist, alpha-helical CRF-(9-41). The effects of stress and exogenous CRF were simulated by intravenous infusion of norepinephrine but prevented by ganglionic, noradrenergic, and alpha-adrenergic but not beta-adrenergic receptor blockade. Vagotomy, adrenalectomy, and--in rats--hypophysectomy did not alter the effects produced by stress and CRF. These results indicate that endogenous CRF released in response to different stressors in distinct species inhibits canine gallbladder contraction and murine exocrine pancreatic secretion via activation of sympathetic efferents. Release of norepinephrine appears to be the final common pathway producing inhibition of biliary and pancreatic digestive function during stress mediated by cerebral CRF.

Animals↗

PubMed1989

Iliac and femoral artery stenoses and occlusions: treatment with intravascular stents.

Forty-five patients with atherosclerotic stenoses and occlusions of the iliac and superficial femoral arteries were treated with a flexible, self-expanding, metallic intravascular stent. Of these patients, 37 were treated immediately after inadequate angioplasty. At a follow-up period of 2-12 months, intravenous digital subtraction angiograms demonstrated patency of the vessels with stents in 40 of 45 patients. The mean Doppler ankle/arm index increased from 0.60 to 0.92 immediately after treatment and was 0.89 at follow-up. Early thrombotic stent occlusion occurred in two patients. Intimal hyperplasia was a late effect and led to stent stenoses in three patients after 5-9 months and stent occlusion in one patient after 6 months. In three patients, percutaneous recanalization with balloon and Simpson catheters was successful. Intravascular stents proved particularly useful for maintenance of patency after angioplasty in occlusions of the iliac and femoral arteries and in treatment of stenoses due to eccentric and severely ulcerated plaques. The stents also helped manage complications after angioplasty. Long-term results will depend on the degree, frequency, and progression of intimal hyperplasia narrowing the vascular lumen.

Adult↗

PubMed1989

[Subjective noise perception and objective measurement of loudness following heart valve replacement with the St. Jude Medical and Duromedics Edwards bileaflet prostheses].

The performance of heart valve prostheses is generally judged by the rate of valve-related complications and the hemodynamic performance. Patients may be severely bothered by the metallic click generated by the closure of the valve. In 74 patients after valve replacement with Duromedics Edwards (DE) (n = 38) and St. Jude Medical (SJM) (n = 36) prostheses the sound energy was recorded and correlated to the complaints of the patients. At a distance of 10 cm the DE valves produced a significantly higher sound pressure with 47 +/- 7 db(A) compared to the SJM valves with 39.8 +/- 5 db(A) (p = 0.001). The noise level was also different for the valves in aortic or mitral position. After splitting into frequency bands the highest sound pressure was observed in the high frequency ranges (8 to 16 kHz) which represents the metallic click. 65% of patients were aware of the noise generated by the valve, 16% had sleep disturbances and 22% would prefer a more silent valve type. 12 of 38 patients with DE valves and 4 of 36 patients with SJM valves wished to have a less noisy valve type (Chi square p = 0.003). In annoyed patients the valves produced a higher sound amplitude of 49 +/- 8 db(A) as compared to undisturbed patients with 42 +/- 6 db(A) (p = 0.002). The noise level of mechanical heart valves should be considered before selection of a prosthesis, because the metallic click bothers patients and the complaints correlate with measured sound energy.

Adult↗

PubMed1986

Gilbert's syndrome: diagnosis by typical serum bilirubin pattern.

Analysis of serum unconjugated and conjugated bilirubin fractions by routine diazo procedures does not allow a definite diagnosis of Gilbert's syndrome. By the alkaline methanolysis procedure of Blanckaert followed by thin-layer chromatography we were able to discriminate Gilbert's syndrome even in the presence of normal serum bilirubin concentrations from healthy subjects, patients with chronic persistant hepatitis and patients with chronic hemolysis. The relative proportion of unconjugated bilirubin in serum was 95 +/- 2% in patients with Gilbert's syndrome (n = 28), 84 +/- 5% in healthy subjects (n = 29), 75 +/- 6% in patients with chronic persistant hepatitis (n = 7) and 85 +/- 3% in patients with chronic hemolysis (n = 9). The difference between Gilbert's syndrome and the control groups with normal or elevated serum bilirubin was highly significant (p less than 0.001). In Gilbert's syndrome, unconjugated bilirubin ranged between 90 and 99%, in healthy subjects between 72 and 90%, in patients with chronic persistant hepatitis between 68 and 85% and in patients with chronic hemolysis between 81 and 89% of total. An overlap was only seen in one patient with Gilbert's syndrome and in 2 healthy subjects at the 90% level. We conclude that in most patients with Gilbert's syndrome provocation tests are no longer necessary.

Adolescent↗

PubMed1986

[Arteriosclerotic aneurysms of the right coronary artery in a 56-year-old female].

We report the case of a 56-year-old woman with a saccular aneurysm of the right coronary artery, which was resected. Aneurysmatic coronary artery disease mostly has an arteriosclerotic origin and occurs in patients with coronary artery disease with a frequency of 0.3-4.9%. In the affected patients myocardial infarction is more frequent, but their 5-year survival rate is not diminished. The therapy of choice is, as indicated, aortocoronary bypass grafting.

Aneurysm↗

PubMed1985

[Transcranial sonographic monitoring of the blood flow of the middle cerebral artery in recanalizing operations of the extracranial internal carotid artery].

During endarterectomy of the internal carotid artery (ICA) blood flow velocity of the ipsilateral medial cerebral artery (MCA) was continuously monitored in twelve patients with the help of a new transcranial pulsed Doppler system. Additionally, the basal cerebral arteries where examined pre- und postoperatively in order to evaluate criteria for selective intraoperative shunting and to document flow improvement following ICA reconstruction. All patients had symptoms, either of TIA or of minor stroke. Five of them had in addition a contralateral ICA occlusion. During intraoperative carotid cross-clamping on the patients with unilateral ICA lesions, MCA blood flow dropped to zero in only one of them. In the other cases, a 20 to 60% flow reduction occurred indicating cross-filling or/and collateral blood supply via the posterior circulation. More severe MCA flow reductions were found in patients with contralateral ICA occlusion, with the occurrence of a no-flow state in two of them. All patients were operated on with an indwelling shunt. Its effect on MCA blood flow varied considerably. Apparently, the shunt was necessary in some patients but was superfluous in the majority of them. Transcranial Doppler meets the basic criteria of an examination technique to be recommended for monitoring. The method is noninvasive. The parameter, i.e. MCA flow velocity, can be evaluated on-line. It is representative and highly sensitive for cerebral circulatory disturbances and impending ischemia in the carotid territory. Transcranial MCA flow monitoring does not affect the course of the operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1985