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Biomedical subjects

J Riehl

Publications and source records attributed to J Riehl.

At least 19 recordsLinked to original sources
PubMed2005

[Renovascular hypertension--diagnosis and therapy].

Atherosclerotic renal artery stenosis accounts for most cases of renovascular hypertension (RVH). Hypertensive patients with clinical features suggesting RVH should be submitted to further noninvasive evaluation including duplex Doppler ultrasonography, CT- or MR angiography. Invasive evaluation by contrast-enhanced angiography confirms the diagnosis of renal artery stenosis. However, neither diagnostic test reliably predicts the course of hypertension after revascularisation. The therapeutic approach in hypertensive patients with hemodynamically important renal artery stenosis includes medical or invasive therapy (renal percutaneous transluminal angioplasty, PTRA; renal arterial stent placement, PTRAS; surgical revascularisation). Randomized trials comparing invasive and conservative approaches demonstrated no differences in blood pressure control or renal function. Only patients with clear clinical indications should be submitted to interventional procedures as PTRA, PTRAS and surgical vascular intervention.

Angioplasty, Balloon↗
PubMed2004

Group B Streptococcus (Streptococcus agalactiae) peritonitis associated with continuous ambulatory peritoneal dialysis (CAPD).

Streptococcus agalactiae typically induces serious infections in pregnant women and newborns. Nonpregnant adult patients can also be infected and mortality rate exceeds 40%. CAPD peritonitis is very rarely induced by S. agalactiae. Seven cases have been described previously and all had a very severe course, which included bacteremia, septic shock and death. A 27-year-old male with end-stage renal disease due to membranoprolipherative glomerulonephritis type I, who was on CAPD for 17 months, was admitted with the clinical and laboratory picture of CAPD peritonitis. Severe abdominal pain, shaking chills and fever 38.5 microC were also observed at presentation. Streptococcus agalactiae was isolated from the peritoneal fluid and blood culture was sterile. Under treatment with ceftazidime and tobramycin (i.p.) and vancomycin (i.v.) cultures became negative after 48 hours, abdominal symptoms resolved after 12 days and WBC count in the dialysate normalized after 14 days. As a possible source of infection the patient's partner was shown to be a vaginal carrier of a clone of S. agalactiae identical to that isolated in the peritoneal fluid. S. agalactiae is a rare cause of CAPD peritonitis with potentially very serious consequences. Anal or genital tract colonization is, in general, the source of contamination with S. agalactiae. The microbiological findings in the case presented here suggest that colonization of the patient or of his close environment may be important in the pathogenesis of S. agalactiae-induced CAPD peritonitis.

Adult↗
PubMed2002

Color-coded duplex sonography study of arteriovenous fistulae and pseudoaneurysms complicating percutaneous renal allograft biopsy.

BACKGROUND: The exact incidence and clinical impact of arteriovenous fistulae (AVF) and pseudoaneurysms as complications emerging from renal allograft biopsy are not well established. We therefore conducted a prospective study using color-coded duplex sonography (CCDS) to determine the frequency, clinical presentation and spontaneous occlusion rate of biopsy-related AVF and pseudoaneurysms in kidney transplant recipients. METHODS: We investigated 72 consecutive patients undergoing renal allograft biopsy using an automated biopsy technique. CCDS was performed before, immediately after and up to more than 6 months after biopsy. The diagnosis of AVF was based on the presence of perivascular vibration artifacts and detection of typical Doppler curves. Pseudoaneurysms were diagnosed based on the presence of"to-and-fro" signals. RESULTS: In 5 patients (6.9%), an AVF was detectable before biopsy. Post-biopsy AVF were found in 12 additional patients (16.7%) with a spontaneous occlusion rate of 50% within 48 hours and 75% after 4 weeks. Three (25%) AVF persisted longer than 1 year. Four patients (5.6%) were found to have pseudoaneurysms. All pseudoaneurysms were located closely to AVF and closed spontaneously. None of the post-biopsy AVF and pseudoaneurysms required specific therapy. In 2 patients (2.8%), allograft biopsy lead to significant hemorrhage independent of AVF or pseudoaneurysms. CONCLUSION: These results indicate that post-biopsy AVF and pseudoaneurysms are a frequent finding after automated renal allograft biopsy. The natural history of these lesions shows a high rate of early occlusion. The present data fail to demonstrate significant clinical impact of AVF and pseudoaneurysms after renal allograft biopsy.

Adult↗
PubMed2001

32-year old patient presenting with autoimmune polyglandular syndrome.

A 32-year-old student reported fatigue and malaise since two months in the absence of specific symptoms. Clinical examination and extensive laboratory testing revealed no abnormalities at his first presentation. Some weeks thereafter, on re-admission, hyperpigmentation suggestive of Addison's disease was observed and pathognomonic autoantibodies directed against the thyroid gland and the adrenal cortex were detected. Further evaluation led to the diagnosis autoimmune polyglandular deficiency syndrome, also named "Schmidt syndrome", comprising adrenocortical insufficiency (Addison's disease) and lymphocytic thyroiditis (Hashimoto thyroiditis). The diagnosis of polyglandular insufficiency is often delayed due to non-specific symptoms at early disease stages and progression may be rapid, culminating in Addisonian crisis under physical stress or infection, requiring immediate high-dose hormone replacement therapy. Hence, careful re-examination is mandatory to ensure adequate treatment before life-threatening complications occur. Nowadays this type of disease is classified as autoimmune polyglandular syndrome type II (APS type II) with an increased risk of developing insulin-dependent diabetes mellitus (IDDM), vitiligo, alopecia, pernicious anaemia, coeliac disease, myasthenia gravis and primary hypogonadism. The cause of the disease remains obscure but in addition to an autosomal dominant trait with variable penetrance some hints at viral infection triggering the disease process exist.

Adult↗
PubMed2000

[Immobilization hypercalcemia as a complication of polyneuropathy].

Prolonged immobilization or physical inactivity has been shown to produce increased bone resorption due to enhanced osteoclastic activity and diminished bone formation. These skeletal changes are a typical complication in tetraplegic patients, who are at risk of developing hypocalcemia. Hypercalciuria is the most characteristic symptom. However, some patients develop hypercalcemia, which is infrequent in these patients, and the hypercalcemia can become a life-threatening complication. Until now, it has been unclear why a small percentage of immobilized patients develop hypercalcemia. Here we present a case of symptomatic hypercalcemia (serum calcium: 3.5 mM/l) following immobilization due to a critical illness polyneuropathy. The diagnosis could be established after malignant hypercalcemia, primary hyperparathyroidism, and other causes of hypercalcemia were excluded. Treatment with intravenous saline, furosemide, and calcitonin was not effective in lowering serum calcium. Treatment with pamidronate (Aredia) was successful and reduced the serum calcium to normal values.

Anti-Inflammatory Agents↗
PubMed2000

Is narcolepsy a REM sleep disorder? Analysis of sleep abnormalities in narcoleptic Dobermans.

Narcolepsy is a chronic sleep disorder marked by excessive daytime sleepiness, cataplexy, sleep paralysis, and hypnagogic hallucinations. Since the discovery of sleep onset REM periods (SOREMPs) in narcoleptic patients, narcolepsy has often been regarded as a disorder of REM sleep generation: REM sleep intrudes in active wake or at sleep onset, resulting in cataplexy, sleep paralysis, or hypnagogic hallucinations. However, this hypothesis has not been experimentally verified. In the current study, we characterized the sleep abnormalities of genetically narcoleptic-cataplectic Dobermans, a naturally occurring animal model of narcolepsy, in order to verify this concept. Multiple sleep latency tests during the daytime revealed that narcoleptic Dobermans exhibit a shorter sleep latency and a higher frequency of SOREMPs, compared to control Dobermans. The total amount of time spent in wake and sleep during the daytime is not altered in narcoleptic dogs, but their wake and sleep patterns are fragmented, and state transitions into and from wake and other sleep stages are altered. A clear 30 min REM sleep cyclicity exists in both narcoleptic and control dogs, suggesting that generation of the ultradian rhythm of REM sleep is not altered in narcoleptics. In contrast, cataplexy displays no cyclicity and can be elicited in narcoleptic animals anytime with emotional stimulation and displays no cyclicity. Stimulation of a cholinoceptive site in the basal forebrain induces a long-lasting attack of cataplexy in narcoleptic dogs; however, bursts of rapid eye movements during this state still occur with a 30 min cyclicity. Sites and mechanisms for triggering cataplexy may therefore be different from those for REM sleep. Cataplexy and a dysfunction in the maintenance of vigilance states, but not abnormal REM sleep generation, may therefore be central to narcolepsy.

Animals↗
PubMed2000

Sulpiride, a D2/D3 blocker, reduces cataplexy but not REM sleep in canine narcolepsy.

Cataplexy, an abnormal manifestation of REM sleep atonia, is currently treated with antidepressants. These medications also reduce physiological REM sleep and induce nocturnal sleep disturbances. Because a recent work on canine narcolepsy suggests that the mechanisms for triggering cataplexy are different from those for REM sleep, we hypothesized that compounds which act specifically on cataplexy, but not on REM sleep, could be developed. Canine studies also suggest that the dopamine D2/D3 receptor mechanism is specifically involved in the regulation of cataplexy, but little evidence suggests that this mechanism is important for REM sleep regulation. We therefore assessed the effects of sulpiride, a commonly used D2/D3 antagonist, on cataplexy and sleep in narcoleptic canines to explore the possible clinical application of D2/D3 antagonists for the treatment of human narcolepsy. Both acute and chronic oral administration of sulpiride (300 mg/dog, 600 mg/dog) significantly reduced cataplexy without noticeable side effects. Interestingly, the anticataplectic dose of sulpiride did not significantly reduce the amount of REM sleep. Sulpiride (and other D2/D3 antagonists) may therefore be an attractive new therapeutic indication in human narcolepsy.

Animals↗
PubMed2000

Chronic oral administration of CG-3703, a thyrotropin releasing hormone analog, increases wake and decreases cataplexy in canine narcolepsy.

The effects on cataplexy and daytime sleep of acute and chronic oral administration of CG-3703, a potent TRH analog were assessed in canine narcolepsy. CG-3703 was found to be orally active and to reduce cataplexy (0.25 to 16 mg/kg) and sleep (8 and 16 mg/kg) in a dose-dependent manner. Two-week oral administration of CG-3703 (16 mg/kg) significantly reduced cataplexy and daytime sleep. The anticataplectic effects of CG-3703 were not associated with changes in general behavior, heart rate, blood pressure, rectal temperature, blood chemistry and thyroid function. Although drug tolerance for the effects on cataplexy and sleep were observed during the second week of chronic drug administration, therapeutic efficacy on cataplexy was improved with individual dose adjustment (final dose range: 16 to 28 mg/kg, p.o.). These results suggest that TRH analogs could be a promising new form of treatment for human narcolepsy.

Animals↗
PubMed2000

Inheritance of von Willebrand's disease in a colony of Doberman Pinschers.

OBJECTIVE: To determine the mode of inheritance of von Willebrand's disease (vWD) and perform linkage analysis between vWD and coat color or narcolepsy in a colony of Doberman Pinschers. ANIMALS: 159 Doberman Pinschers. PROCEDURE: von Willebrand factor antigen (vWF:Ag) concentration was measured by use of ELISA, and results were used to classify dogs as having low (< 20%), intermediate (20 to 65%), or high (> 65%) vWF:Ag concentration, compared with results of analysis of standard pooled plasma. Buccal bleeding time was measured, and mode of inheritance of vWD was assessed by pedigree analysis. RESULTS: von Willebrand's disease was transmitted as a single autosomal gene defect. Results suggested that 27.04% of dogs were homozygous for vWD, 62.26% were heterozygous, and 10.69% did not have the defect. Most homozygous and some heterozygous dogs had prolonged bleeding times. Dogs with diluted coat colors (blue and fawn) were significantly overrepresented in the homozygous group, compared with black and red dogs, but a significant link between vWD and coat color was not detected. CONCLUSIONS AND CLINICAL RELEVANCE: von Willebrand's disease is transmitted as an autosomal dominant trait with variable penetrance; most dogs in this colony (89.3%) were carriers of vWD. Homozygosity for vWD is not likely to be lethal. Some heterozygous dogs have prolonged bleeding times. An association between diluted coat colors and vWD may exist.

Animals↗
PubMed1999

Dopamine D3 agonists into the substantia nigra aggravate cataplexy but do not modify sleep.

We have recently demonstrated that local perfusion of dopaminergic D2/D3 agonists into the ventral tegmental area (VTA) significantly aggravates cataplexy and increases sleep in narcoleptic Dobermans. We further assessed the roles of the mesostriatal dopaminergic system and found that local perfusion of quinpirole and 7-OH-DPAT into the substantia nigra (SN) significantly aggravated cataplexy, while perfusion of a D2/D3 antagonist significantly reduced cataplexy. Neither a D1 agonist nor a D1 antagonist modified cataplexy. SN perfusion of quinpirole did not significantly modify sleep, while VTA perfusion significantly increased the drowsy state. Although autoregulation of the VTA and SN dopaminergic neurons are involved in the regulation of cataplexy, both structures have distinct roles for the regulation of sleep.

Animals↗
PubMed1999

Dopamine D3 agonists into the substantia nigra aggravate cataplexy but do not modify sleep [corrected].

We have recently demonstrated that local perfusion of dopaminergic D2/D3 agonists into the ventral tegmental area (VTA) significantly aggravates cataplexy and increases sleep in narcoleptic Dobermans. We further assessed the roles of the mesostriatal dopaminergic system and found that local perfusion of quinpirole and 7-OH-DPAT into the substantia nigra (SN) significantly aggravated cataplexy, while perfusion of a D2/D3 antagonist significantly reduced cataplexy. Neither a D1 agonist nor a D1 antagonist modified cataplexy. SN perfusion of quinpirole did not significantly modify sleep, while VTA perfusion significantly increased the drowsy state. Although autoregulation of the VTA and SN dopaminergic neurons are involved in the regulation of cataplexy, both structures have distinct roles for the regulation of sleep.

Animals↗
PubMed1999

Successful treatment of pulmonary Mycobacterium xenopi infection in a natural killer cell-deficient patient with clarithromycin, rifabutin, and sparfloxacin.

Isolation of Mycobacterium xenopi from the respiratory tract may indicate pneumonia, often clinically indistinguishable from tuberculosis. Resistance to the classic antituberculous drugs renders the treatment of these infections problematic. We report on a case of cavernous pneumonia caused by M. xenopi in a 36-year-old male with natural killer cell deficiency but without severe immunodeficiency. He was successfully treated with a novel triple-drug combination comprising clarithromycin, sparfloxacin, and rifabutin. An impressive subsequent regression of pathological pulmonary changes was observed, and mycobacteria could no longer be detected. The therapeutic potential of clarithromycin and sparfloxacin in the treatment of M. xenopi infections is discussed.

Adult↗
PubMed1999

Dialysis and pregnancy--a case report and review of the literature.

We report on a patient with an eight-year history on maintenance hemodialysis treatment without residual renal function in whom pregnancy was successfully managed through to the 29th week. During this time, under carefully modified dialysis treatment, the nephrologic course, as well as materno-fetal flow relationships were unremarkable. Fetal development was appropriate for gestational age. However, pregnancy was complicated by polyhydramnios, which necessitated i.v. tocolysis. In the 28 + 6th week of gestation, cesarean section was performed because of an antibiotic-resistant fever of unclear origin which ceased within two days of delivery. Although the postnatal course of the adequately developed baby was complicated by the respiratory distress syndrome, normal development continued. We emphasize that the intensive interdisciplinary cooperation of nephrologists and obstetricians is imperative for the successful management of pregnancy under these conditions. In these pregnancies, the main fetal problems consist of premature labor because of polyhydramnios, preterm delivery, intrauterine growth retardation and stillbirth. The mother is threatened by the development of superimposed pre-eclampsia, left ventricular failure because of volume overload and progressive anemia. In order to maintain a well-balanced homeostasis, intensification of dialysis therapy by an increase in frequency and duration is the most important therapeutic approach. Accurate fetal monitoring including frequent examination of the feto-maternal circulation by Doppler sonography as well as attentive surveillance of the mother is required to recognize the above mentioned complications.

Adult↗
PubMed1998

Neuronal activity in the cholinoceptive basal forebrain of freely moving narcoleptic dobermans.

Cholinergic stimulation in the basal forebrain (BF) triggers cataplexy in canine narcolepsy. Extracellular single unit recordings in the BF were carried out in freely moving narcoleptic dogs to study the neuronal mechanisms mediating cataplexy induction in the BF. Among the 64 recorded neurons, 12 were wake-active, three were slow wave sleep (SWS)-active, 17 were wake-/REM-active, 11 were REM sleep-active, three were cataplexy-active, and the other 18 were state-independent. Systemic administration of physostigmine, a cholinesterase inhibitor, induces status cataplecticus, decreases SWS and increases acetylcholine levels in the BF. Firing of most of the state-dependent neurons in the BF was significantly modified by physostigmine. Some of these neurons may thus mediate sleep stage changes or the effect on cataplexy observed after cholinergic stimulation in the BF.

Acetylcholine↗
PubMed1998

Development of cataplexy in genetically narcoleptic Dobermans.

Forty-two genetically narcoleptic Doberman puppies [20 pure narcoleptic (N) puppies (from four narcoleptic x narcoleptic crosses) and 22 backcross narcoleptic (BN) puppies (from six narcoleptic x heterozygous crosses)] were systematically observed during the developmental period (4-24 weeks) to assess the age at onset and severity of cataplexy, a pathological manifestation of REM sleep atonia seen in narcolepsy. The mean age of onset of cataplexy was 9.69 +/- 1.15 weeks, with a median age of 7 weeks. The severity of cataplexy increased with age and reached a plateau at around 16-24 weeks. The effects of cross type (N vs BN) and sex on the development of cataplexy were analyzed. There was no difference in severity between N and BN puppies (P = 0.51). However, females had more severe cataplexy than males (P = 0.01), and this trend was preserved in five of the six litters that had both male and female puppies. These results suggest that the pathophysiological process in genetic canine narcolepsy emerges during the early developmental period and that it may involve a differential development in males and females. Furthermore, our results revealed that cataplexy onset corresponds to the emergence of adult-like REM sleep and to previously reported neuroanatomical and neurochemical abnormalities in canine narcolepsy.

Age of Onset↗