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Biomedical subjects

R Niehues

Publications and source records attributed to R Niehues.

At least 19 recordsLinked to original sources
PubMed2000

[Carbohydrate-deficient glycoprotein syndrome (CDGS) type Ib. A hereditary metabolic disease and its therapy].

Underlying the carbohydrate-deficient glycoprotein syndrome (CDGS) type 1b is a defect in phosphomannose isomerase (PMI), an enzyme of mannose metabolism. The clinical manifestations include exudative gastroenteropathy, thromboses and hemorrhages. In contrast to other forms of the CDGS syndrome, neurological symptoms are completely lacking. The condition responds to a simple dietetic treatment employing the monosaccharide mannose.

Congenital Disorders of Glycosylation↗
PubMed2000

[Interventions in carotid stenoses: carotid srugery, percutaneous transluminal balloon angioplasty and stent implantation. Indications, results of clinical studies. An overview].

Ischemic stroke is the third most reason of death and the main reason of severe disability in Western countries. The high incidence of stroke, 330 per 100,000 subjects in Germany, illustrates the importance of the disease. Generally, atherosclerotic stenosis of the proximal internal carotid artery is the responsible mechanism. The clinical efficiency of surgically performed endarterectomy has been demonstrated in several large multicenter trials. Proven indications for endarterectomy are symptomatic moderate to high-grade stenoses, rapidly progressive asymptomatic stenoses and asymptomatic patients with lesions revealing greater than sixty percent diameter stenosis under certain clinical conditions. Reduction of the incidence of cerebrovascular events, though, is only possible if a low perioperative complication rate is accomplished. Recommendations of the American Heart Association demand a total periprocedural complication rate less than six percent for symptomatic and less than three percent for asymptomatic stenoses. Implantation of stents in carotid arteries is a promising method which might expand the spectrum of indications toward stenosis morphology unfavorable for surgery and patients with significant comorbidity. Clinical results reveal primary success rates, complication rates, and restenosis rates comparable with those of surgical endarterectomy. Randomized trials, comparing both methods, are necessary and reasonable. Yet results are not available at the moment.

Angioplasty, Balloon↗
PubMed2000

[Carotid stenting with the new slotted tube stent--prospective multicenter study. Essen experiences]].

UNLABELLED: The indication for therapy of high degree carotid stenoses is discussed controversely in regard to new publications. Only symptomatic carotid stenoses are accepted as indication for operative therapy (arterectomy). The new method of carotid stenting was investigated in several studies and needs to be proved in controlled prospective randomized trials. The use of the self-expanding wall-stent has been established in most working groups; nevertheless some disadvantages should be considered (uncontrolled long segment stenting, covering the origin of ext. carotid artery, insufficient adaptation of struts in carotid communis). After development of a new flexible multicellular balloon-expanding stent (Jo-Carotisstent) with sufficient flexibility and compressibility and different stent lengths, the use of this stent in high degree carotid stenoses was investigated. The aim of this study was to analyze the acute and long-term quantitative stent results (angiography and duplex sonography) and clinical results periinterventionally and during follow-up (0.5-1 year). METHODS: Selective approach from femoral, 8 Fr.-guiding catheter, canalization of stenosis with coronary guide wire (0.014 inch), primary PTA with coronary balloon. RESULTS: In 47 of 48 patients with 49 carotid stenoses, successful stent implantation was achieved (97.9%). In 2 patients TIA of short duration (4.2%) and in 1 patient (2.1%) a minor stroke occurred. All stents could be implanted with optimal reference diameter. During follow up after 0.5 year no significant proliferative restenosis was observed. The quantitative analysis showed excellent stent-diameter after 0.5 year with only minimal recoil (< 5%) and no clinical event. CONCLUSION: Using a new flexible and non-deforming multicellular balloon-expanded stent, selective stenting of high degree carotid artery stenoses can be realized with an excellent procedural success rate and a complication rate comparable with the results of other publicated studies. The results after 0.5 year follow-up seem to be promising.

Aged↗
PubMed1999

[Calcifying aortic valve stenosis and occult gastrointestinal hemorrhage (Heyde syndrome): description of 2 cases].

The coincidence of aortic valve stenosis and cryptogenic gastrointestinal bleeding usually from angiodysplasia of the cecum and ascending colon has been called Heyde syndrome. The pathophysiologic link between both remains unclear and may be due to subtle changes in plasmatic coagulation. There are some statistic and numerous casuistic reports, and recently the existence of the syndrome has been questioned. We describe two cases of aortic valve stenosis and cryogenic gastrointestinal bleeding in which bleeding subsided after replacement with a bioprosthesis. We give an overview of the current literature.

Aged↗
PubMed1998

Carbohydrate-deficient glycoprotein syndrome type Ib. Phosphomannose isomerase deficiency and mannose therapy.

Phosphomannose isomerase (PMI) deficiency is the cause of a new type of carbohydrate-deficient glycoprotein syndrome (CDGS). The disorder is caused by mutations in the PMI1 gene. The clinical phenotype is characterized by protein-losing enteropathy, while neurological manifestations prevailing in other types of CDGS are absent. Using standard diagnostic procedures, the disorder is indistinguishable from CDGS type Ia (phosphomannomutase deficiency). Daily oral mannose administration is a successful therapy for this new type of CDG syndrome classified as CDGS type Ib.

Cells, Cultured↗
PubMed1998

[IVUS-controlled aorto-ostial directional coronary atherectomy in higher grade stenosis of the central anastomosis of a sequential triple venous bypass].

Following coronary artery bypass grafting repeat ischemia mandatory for reintervention occurs in 2 to 30% of cases, depending mainly on graft age. Selection of a suitable strategy for revascularisation--transcatheter angioplasty or reoperation--depends on various parameters including coronary morphology, left ventricular performance, comorbidity and availability of graft material. Catheter-based interventions on saphenous vein bypass grafts are feasible, but lower primary success rates and a higher incidence of restenosis--compared with native coronary arteries--have to be expected. Repeat coronary artery bypass graft operations are associated with a significantly higher perioperative morbidity and mortality, patency rates are lower and late clinical outcome is worse than in primary surgery. We report on a patient who underwent coronary artery bypass grafting 4 years ago revealing a high grade ostial stenosis in a jump-graft supplying RCA, LAD and Cx sequentially, making reintervention necessary. As a prerequisite serial balloon angioplasty of two native vessels was performed prior to ostial intervention. Intravascular-ultrasound guided directional coronary atherectomy was performed with good primary and long-term result. Our case demonstrates that, if all relevant clinical parameters and different therapeutic options are taken into account, complex transcatheter angioplasty procedures are feasible and associated with a reasonable amount of risk, thus avoiding repeat coronary artery bypass graft operations.

Anastomosis, Surgical↗
PubMed1998

Direct utilization of mannose for mammalian glycoprotein biosynthesis.

Direct utilization of mannose for glycoprotein biosynthesis has not been studied because cellular mannose is assumed to be derived entirely from glucose. However, animal sera contain sufficient mannose to force uptake through glucose-tolerant, mannose-specific transporters. Under physiological conditions this transport system provides 75% of the mannose for protein glycosylation in human hepatoma cells despite a 50- to 100-fold higher concentration of glucose. This suggests that direct use of mannose is more important than conversion from glucose. Consistent with this finding the liver is low in phosphomannose isomerase activity (fructose-6-P<->mannose-6-P), the key enzyme for supplying glucose-derived mannose to the N-glycosylation pathway. [2-3H] Mannose is rapidly absorbed from the intestine of anesthetized rats and cleared from the blood with a t1/2of 30 min. After a 30 min lag, label is incorporated into plasma glycoproteins, and into glycoproteins of all organs during the first hour. Most (87%) of the initial incorporation occurs in the liver, but this decreases as radiolabeled plasma glycoproteins increase. Radiolabel in glycoproteins also increases 2- to 6-fold in other organs between 1-8 h, especially in lung, skeletal muscle, and heart. These organs may take up hepatic-derived radiolabeled plasma glycoproteins. Significantly, the brain, which is not exposed to plasma glycoproteins, shows essentially no increase in radiolabel. These results suggest that mammals use mannose transporters to deliver mannose from blood to the liver and other organs for glycoprotein biosynthesis. Additionally, contrary to expectations, most of the mannose for glycoprotein biosynthesis in cultured hepatoma cells is derived from mannose, not glucose. Extracellular mannose may also make a significant contribution to glycoprotein biosynthesis in the intact organism.

Administration, Oral↗
PubMed1996

[Systemic Nocardia asteroides infection with endocardial involvement in a patient undergoing immunosuppressive therapy].

HISTORY: A 62 year-old male patient developed malaise, unproductive cough and high temperature (39.5 degrees C) during immunosuppressive therapy with methylprednisolon and cyclosporin A six months after kidney transplantation for glomerulonephritis. INVESTIGATIONS: Clinical examination revealed an endophthalmitis and chest X ray a left-sided lobar pulmonic infiltration. Computed tomography and magnetic resonance imaging examination performed because of recurrent petit-mal-convulsions demonstrated multiple intracranial infiltrations. Transoesophageal echocardiography revealed floating vegetations up to 8 mm in diameter predominantly attached to the aortic valve. A total of 39 consecutive blood cultures drawn during several days remained sterile. However, Nocardia asteroides (Biovar A1) was isolated from a small cutaneous tumor excised from the right thigh. TREATMENT AND COURSE: After initiation of a specific antibiotic treatment with imipenem/cilastatin (each 1 g three times daily), and doxycyclin (100 mg twice daily), computed tomography and magnetic resonance imaging showed a reduction in size and number of the intracranial infiltrations. Neurological symptoms were progressive despite maximal anticonvulsant therapy. The patient died 83 days after hospital admission from an epileptic state resistant to therapy. CONCLUSION: Though nocardiosis is still rare, it should early be included in the differential diagnosis of infections in immunocompromised patients to allow timely diagnosis and therapy.

Anti-Bacterial Agents↗
PubMed1996

[Value of rotational ablation in reopening chronic coronary artery occlusion].

UNLABELLED: Previous studies, including our own prospective study (634 patients), on chronic coronary artery occlusion demonstrated the highest success rate in reopening by primary use of conventional guidewire technique. The present prospective randomized study in 124 patients investigates the role of high-speed rotational angioplasty after primary guidewire-recanalization in comparison to sequential PTCA. Early results were described by analyzing the residual degree of stenosis, early dissection, stabile dissection at the end of procedure, complicated dissection, necessity of stent implantation, acute re-occlusion, restenosis or reocclusion during recoronary angiography after 24 h, and infarction. Despite the advantage of rotablation with significant reduction of early and stabile dissections (p < 0.01) only slight difference in restenosis-rate and comparable results for the rest parameters were achieved. CONCLUSION: Results of this study demonstrate no advantage in using rotablation after recanalization of chronic coronary occlusion in comparison to sequential PTCA.

Adult↗
PubMed1996

[Conventional therapeutic strategy in PTCA-induced dissection: long-term re-PTCA, early re-coronary angiography].

A prospective randomized trial in 324 patients (pts.) analyzed the early clinical course of stabile dissections (stabile perfusion, degree of residual stenosis > 50% < 70% and stabile early result after 24 h). The results of quantitative recoronary angiography after 6 weeks and 3-4 months with differentiated reintervention (long time-PTCA, atherectomy, stent, CABG) were analyzed to determine the early clinical course. 57% of pts. demonstrated a type-I dissection (excentric stabile dissection with quantifiable degree of residual stenosis). By early recoronary angiography after 6 weeks with differentiated reintervention 68% of pts. (125 pts.) showed a sufficient result after 3.8 months. In 51% of pts. an additional sufficient result could be achieved by a second reintervention after 1/4 year. Considerable complications (infarction, CABG, acute death) occurred in 2.7% of pts. with type-I dissections. 108 pts. (33%) could be classified with type-II dissection (diagonal flap). Sufficient result after 3.5 months could be achieved in 84% pts. In 20 of 22 pts. an additional successful reintervention could be performed. The complication-rate (infarction, CABG) was 5.5%. In pts. with type-IV dissection (complex dissection) the early clinical course was more unfavorable with higher restenosis rate and considerable complications of 10%. The rare type-III dissection (short spiral dissection) showed a high recurrence rate already after 6 weeks (33%) and sufficient results after 3.2 months only in 42% of pts. Complication rate was high with 50% (2 x deaths, 2 x CABG).

Adult↗
PubMed1995

[Acute myocardial ischemia in spontaneous coronary artery spasm].

AIM OF STUDY: To discover what factors indicate spontaneous coronary artery spasms as a cause of myocardial ischaemia. PATIENTS AND METHOD: In a retrospective analysis 15 of 1407 consecutive patients who had undergone coronary arteriography (six women and nine men; mean age 47 +/- 11 years) had acute ischaemia due to spontaneous coronary artery spasms. The clinical findings at the time of first investigation and during the follow-up period (mean of 29 [3-65] months) were evaluated. RESULTS: The most common risk factors were hypercholesterolaemia (> or = 200 mg/dl) in ten patients (66%) and heavy nicotine consumption > or = 20 cigarettes per day) in eight patients (55%). Of the patients with angina at rest nine had reversible ST elevations, six had terminal T negativity in the ECG and an increased incidence of ventricular arrhythmias (n = 6). At time of hospitalization ten patients had acute myocardial ischaemia and five had signs of acute myocardial infarction (maximal creatine kinase concentration: 121-2980 U/l). Acute coronary angiography revealed circumscribed coronary artery constriction, reversible with nitroglycerin, with stenosis of < 70% in five patients and of > or = 70% in six, as well as intermittent vessel occlusion in four patients. Angiography showed smooth coronary artery walls in almost all instances. Angiographic evidence of circumscribed arteriosclerotic lesion with maximally 50% narrowing was present in six patients. CONCLUSION: Especially in younger, male patients with hypercholesterolaemia and heavy smoking recurrent anginal pectoris at rest, with reversible ECG signs of myocardial ischaemia but without advanced coronary sclerosis, speaks for spontaneous coronary artery spasms as the cause.

Acute Disease↗
PubMed1995

[Repeated ingestion with suicidal intent of potentially lethal amounts of thallium].

30 minutes after drinking half a cup of rat poison a 16-year-old girl was admitted to hospital. In addition to various enteric detoxification measures forced dialysis was instituted and, after the urinary thallium level had become known (9 mg/l), haemodialysis was begun and ferric ferrocyanide (Prussian blue) administered (0.5 mg daily for six days). She had no symptoms at any time. After 10 days she was discharged. Five days after discharge she was again admitted, with colic-like abdominal pain, vomiting, paraesthesias of the hands and feet, and in a state of agitation. She had once again ingested rat poison, about one cup. Physical examination revealed little of consequence, except diffuse alopecia. Urinary thallium concentration was 37 mg/l. In the electrocardiogram the P-R interval was shortened to 0.11 s and T waves inverted in leads III and V1. Electronmicroscopy of cardiac and skeletal biopsies revealed lipid droplets, increased sarcoplasm and widening of some of the tubules. Treatment consisted of haemodialysis, forced diuresis (1 l urine/h), administration of ferric ferrocyanide, orthograde intestinal infusions and potassium substitution (serum level: 5 mmol/l). After 28 days the patient was discharged into psychiatric care.

Adolescent↗
PubMed1995

Late prosthetic valve endocarditis.

Prosthetic valve endocarditis remains an extremely serious complication, with a low but increasing incidence. 'Late' endocarditis, occurring more than 60 days after surgery, is relatively infrequently associated with staphylococci, Gram-negative bacteria and fungi so characteristic of the endocarditis that occurs earlier. A probable source of infection can be found in 25%-80% of patients, the most frequent causes being dental procedures, urological infections and interventions, and indwelling catheters. The most common organisms are S. epidermidis, S. aureus, viridans streptococci and enterococci. The general principles of antibiotic treatment are similar to those for native valve endocarditis, but antibiotic treatment needs to be more prolonged and dosages should be used which result in maximal, nontoxic concentrations. Oral anticoagulants should be stopped and replaced by intravenous heparins. Surgical reintervention is called for if there are large highly mobile vegetations in the mitral position or within 72 h if there are cerebral thrombo-embolic episodes.

Endocarditis, Bacterial↗
PubMed1994

[Exercise capacity after heart valve replacement].

Exercise capacity following heart-valve replacement is dependent on how close to normal the artificial device can restore valve function, to what degree a preoperative impaired myocardial function and/or an increased pulmonary vascular resistance is normalized. The postoperative functional result can be determined by the subjective improvement of the patient, his functional capacity, exercise capacity, the central hemodynamics at rest and during exercise, and the systolic and diastolic function of the left and right ventricular myocardium. The subjective improvement of individual symptoms is obviously dependent on the degree of postoperative normalization of hemodynamics, especially of pressures in the pulmonary circulation. Subjective improvement can be objectified by comparing the functional capacities before and after surgery. Post-operative normalization of central hemodynamics and myocardial function does not happen immediately but within 3 to more than 12 months. A 12-month period can generally be expected in patients with mitral stenosis and increased pulmonary vascular resistance (> 400 dyn.sec.cm-5) prior to surgery. In patients with mitral and aortic regurgitation as well as with aortic stenosis and preoperative decrease of their left ventricular ejection fraction during exercise, continuous improvement of left ventricular pump function also may need up to 12 months. Physiological hemodynamic conditions generally are not restored by valve replacement. All prostheses are stenotic to forward blood flow because of the obstruction created by the narrowing of the valve area by sewing cuff and valve poppet. This may result in a hemodynamically important stenosis, especially after atrio-ventricular valve implantation, and may limit subjective and functional improvement. Exercise capacity after aortic valve replacement depends mainly on whether or not myocardial damage persists postoperatively. A workload of 1.5 w/kg body weight (BW) has been performed by 100% of patients aged 45 to 55 years with prostheses implanted for aortic stenosis. The significant lower exercise capacity all patients with valve replacement for aortic regurgitation have experienced (0.4 w/kg BW) indicates that a substantial number of these patients has irreversible myocardial damage prior to surgery. The workload experienced by patients with mitral valve prostheses varies between 0.4 and 2.0 w/kg BW (mitral stenosis) and 0.3-2.3 w/kg BW (mitral regurgitation), respectively. To objectify the functional result of heart-valve replacement, hemodynamic-metabolic measurements of functional improvement, determination of left, eventually also of right-ventricular function by echocardiography and additional invasive measurements of the central hemodynamics and myocardial pump function parameters at rest and during exercise might be necessary.

Adult↗
PubMed1993

Diagnostic and therapeutic considerations in acute, severe mitral regurgitation: experience in 42 consecutive patients entering the intensive care unit with pulmonary edema.

Forty-two consecutive patients received emergency treatment for acute mitral insufficiency causing pulmonary edema between 1984 and 1992. The underlying diagnoses were acute myocardial infarction (n = 21), acute bacterial endocarditis on the native mitral valve (n = 9), prosthetic endocarditis in the mitral position (n = 4), acute failure of a replacement valve (n = 5), blunt chest trauma (n = 1) and chordal rupture in Marfan's syndrome (n = 2). Dysfunction of the subvalvular apparatus was present in 24 patients, verified by transthoracic echocardiography in 18 (75%) and by transoesophageal echocardiography in all patients in whom this technique was used. There were four cases of outflow strut fracture of a Björk-Shiley mitral prosthesis; a reliable diagnosis was made by fluoroscopy in all patients. Bedside hemodynamic monitoring was found to be unreliable both for differential diagnosis and for the quantitative assessment of the degree of mitral insufficiency. The right ventricular filling pressure was normal in 32/39 patients (82%), and the pulmonary artery and pulmonary capillary pressures elevated in 37/39 (95%). Diagnostically important, high pulmonary capillary v-waves were documented in 13 patients (33%). The left ventricular impedance could be influenced with sodium nitroprussid combined in some cases with dobutamin, and the resultant decrease of the peripheral vascular resistance from 1480 +/- 222 to 702 +/- 86 dyn x sec x cm-5 was followed by a proportionate reduction in the transmitral regurgitant fraction. Three patients died prior to the intended emergency surgical intervention. Emergency surgery was completed in 21 patients with an early mortality of 23.8% (n = 5). Ten patients underwent elective surgery within, and another three later than one year from the onset of the acute symptoms with an early mortality of 7.7% (n = 1). Four patients are alive and clinically well with medical treatment alone.

Adult↗
PubMed1992

[The local lysis therapy of spontaneous renal artery dissection with arterial thrombosis].

A 33-year-old previously completely healthy man developed severe, at first colicky then persisting, pain in the left flank. The blood pressure was 190/110 mm Hg and he had pain over the left kidney on percussion. There was a mild leucocytosis (10,300/microliters), serum creatinine of 1.5 mg/dl and a rise in lactate dehydrogenase level to 395 U/l, while the urine was unremarkable. The pyelogram demonstrated on the left the upper calyceal system only and this very weakly. Colour Doppler ultrasound showed a massively reduced blood flow in the left renal vein while the artery was not visible. Digital subtraction angiography demonstrated eccentric narrowing of the left renal artery by an intravascular thrombus, providing the diagnosis of spontaneous renal artery dissection with thrombosis. Complete recanalization occurred after local thrombolysis with 500,000 IU urokinase over 7 hours, and subsequent administration of four times 40 mg tissue plasminogen activator over 4 hours. But the scintigram still demonstrated impaired renal function with decrease in clearance to 10% of total. The patient was still symptom-free on re-examination 16 months later, serum creatinine concentration was stable at 1.3 mg/dl and the blood pressure was normal.

Adult↗