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Biomedical subjects

G Mayer

Publications and source records attributed to G Mayer.

At least 163 records · Page 9Linked to original sources
PubMed1995

Cephalometric predictors for orthopaedic mandibular advancement in obstructive sleep apnoea.

The cephalometric analysis of two groups: 30 sleep apnoea patients, and 30 age- and sex-matched control patients, established predictors for the orthopaedic mandibular advancement by means of the Esmarch device (ED) in treating obstructive sleep apnoea (OSA). Polysomnographic sleep and ventilation data gathered for each patient with and without mandibular advancement by means of the ED were compared. Cephalometric data and treatment efficacy for each patient were submitted to a regression analysis. Maximal efficacy is predicted by: 1. The combination of an orthognathic to prognathic maxilla (SNA larger than or equal to 83 degrees) with an orthognatic to retrognathic mandible (SNB less than or equal to 77 degrees) 2. An anterior superior displacement of the mandible, with the supramentale situated at a distance from the anterior part of second cervical vertebra (B-HWK 2 longer than or equal to 95.5 mm) and a narrow angle between the skull and the mandibular ramus (SN/B-Go equal to or less than 1.5 degrees) 3. Short oral height (TB-PNS equal to or less than 35.5 mm), with the uvula not extending beyond the tongue base (UT-PNS, equal to or less than 30 mm). 4. A narrow oropharynx (PAS equal to or less than 3.4 mm). The narrower the SNB-angle, the wider the SNA-angle, and the shorter the uvula, the more effective the device.

Adult↗
PubMed1995

Selegeline hydrochloride treatment in narcolepsy. A double-blind, placebo-controlled study.

The relative benefits of selegeline hydrochloride (2 x 5 mg, 2 x 10 mg selegeline) were studied in 30 narcoleptic patients using a randomized, double-blind, placebo-controlled design. Patients were randomly assigned to three groups (placebo and 2 x 5 mg and 2 x 10 mg selegeline). After a 2-week washout period for previous anticataplectic and stimulant medication, the study started with a 2-day period of placebo intake for each group, continued by 14 days of medication, ending with a 2-day placebo period. Outcome was measured by comparison of four polysomnographies and four multiple sleep latency tests (MSLTs) performed during the initial and the final placebo and medication period. Each MSLT day included acoustic and visual vigilance tests. Blood pressure and pulse rate were monitored daily. Patients reported daily about mood, concentration, subjective sleep time, nocturnal awakenings, nocturnal wake times, number of naps, and occurrence of symptoms of the narcoleptic tetrad. Selegeline caused dose-dependent REM suppression during nighttime sleep and naps and increase of sleep and REM latency. Under selegeline, daytime sleepiness improved significantly and the number of sleep attacks and naps as well as the frequency of cataplexy were reduced. Selegeline at a dose of a least 20 mg/day is a potent drug for the treatment of all narcoleptic symptoms.

Adolescent↗
PubMed1995

Prevalence of acquired cystic kidney disease and tumors in native kidneys of renal transplant recipients: a prospective US study.

PURPOSE: To determine the prevalence of acquired cystic kidney disease (ACKD) and renal neoplasms in the native kidneys of renal transplant recipients. MATERIALS AND METHODS: The ultrasound (US) scans in 385 renal allograft recipients were prospectively studied. In addition, 65 patients with ACKD underwent two additional US examinations on different days to assess intra- and interobserver variability with regard to the number of cysts and their diameter. RESULTS: ACKD was present in 96 of 385 patients. Patients with ACKD were significantly older than patients without ACKD, had undergone hemodialysis for a longer period, and were predominantly men. There was no significant difference in the time with functioning graft. Renal cell carcinoma (RCC) was diagnosed in six patients at histologic examination. Of these six patients, five had evidence of ACKD. CONCLUSION: The frequency of ACKD increases with the duration of hemodialysis. The risk for the development of ACKD is increased in men and older patients. The malignant potential of ACKD persists after renal transplantation.

Adult↗
PubMed1995

Glomerular permselectivity in proteinuric patients after kidney transplantation.

To characterize the defect in glomerular permselectivity responsible for proteinuria after renal transplantation, we studied 10 patients with moderate proteinuria (median 0.37 g/d, range 0.20-0.79), 16 patients with the nephrotic syndrome (6.73 g/d, 3.9-14.6), 8 living related donor transplant recipients without any history of rejection (median proteinuria 0.26 g/d, 0.06-0.58), and 12 healthy volunteers. The fractional clearance of neutral dextrans > 54 A was significantly higher in nephrotic patients, demonstrating a defect in glomerular size selectivity. Using a log-normal model of glomerular pore size distribution, r*(5%) and r*(1%), indices for the presence of large pores, were increased in the nephrotic patients. The fractional clearance of negatively charged dextran sulfate was significantly higher in all patient groups, indicating a loss of glomerular charge selectivity. Biopsy findings showed more prominent glomerular lesions in the nephrotic group compared with the moderately proteinuric group. We conclude that mild proteinuria late after renal transplantation is associated with a defect in glomerular charge selectivity. The development of nephrotic range proteinuria is associated also with a defect of glomerular size selectivity, which correlates with prominent glomerular pathology.

Adult↗
PubMed1995

The effects of prolonged substitution of recombinant human growth hormone on renal functional reserve in growth hormone-deficient adults.

Twelve growth hormone (GH)-deficient adults with normal renal function were recruited for a 6-month, double-blind, placebo-controlled study on the effects of prolonged recombinant human growth hormone (rhGH) substitution therapy on renal functional parameters. RhGH was administered at a dose 0.125 IU/kg per week sc the first 4 wk and 0.25 IU/kg per week thereafter. At baseline and after 6 months of therapy, GFR and RPF were measured by the use of iothalamate and para- aminohippurate clearance techniques before and after an intravenous infusion of amino acids (AA) to determine the renal functional reserve capacity (RFRC). At baseline, GFR and RPF were similar in the GH-deficient patients and a group of normal, healthy controls (GFR, 117 +/- 10 mL/min; RPF, 567 +/- 57 mL/min, and filtration fraction, 22 +/- 1.6% in the patient group and GFR, 117 +/- 10 mL/min; RPF, 509 +/- 54 mL/min; and filtration fraction, 24 +/- 1.3% in the control group). GFR increased significantly in the control and patient group after AA infusion; the RFRC, however, was significantly larger in healthy individuals (GFR post-AA infusion, 141 +/- 10 mL in GH-deficient patients and 182 +/- 20 mL/min in controls). Thereafter, six patients received placebo therapy for 6 months and GFR as well as RFRC remained constant (GFR, 107 +/- 9 and 106 +/- 12 mL/min before AA infusion and 132 +/- 14 and 134 +/- 5 mL/min after AA infusion at baseline and after 6 months, respectively). Four patients of the placebo group then continued with rhGH therapy for another 6 months. They and six patients who had rhGH therapy from the beginning form the rhGH treatment study group. During rhGH treatment, plasma insulin-like growth factor activity increased significantly from 93 +/- 17 to 229 +/- 23 ng/mL. Baseline GFR and RPF as well as RFRC were unaltered by the 6 months of rhGH replacement therapy (basal GFR, 124 +/- 7 mL/min before and 123 +/- 9 mL/min after 6 months of rhGH therapy; GFR after AA infusion, 145 +/- 9 mL/min at baseline and 144 +/- 8 mL/min after 6 months of therapy). Kidney size as evaluated by ultrasonography was normal at baseline when compared with that in age- and sex-matched controls (10.3 +/- 0.2 versus 9.9 +/- 0.1 cm) and was unchanged after 6 months of therapy (10.3 +/- 0.3 cm). It was concluded from this study that rhGH substitution for 6 months at a dose of 0.25 IU/kg per week in GH-deficient patients with normal renal function has no adverse functional effects on the kidney.

Adult↗
PubMed1995

More adverse renal prognosis of autosomal dominant polycystic kidney disease in families with primary hypertension.

Marked variability of age at renal death is noted in autosomal dominant polycystic kidney disease (ADPKD). The hypothesis that the coexistence of primary hypertension and ADPKD within families is associated with earlier renal death was tested. Of a total of 162 ADPKD patients treated in one Austrian and three German centers, 57 propositi were identified whose families provided (1) information concerning blood pressure; (2) documented presence of ADPKD (by sonography or autopsy) in one parent; and (3) age at renal death in the propositus. Hypertension of the unaffected parent was defined as blood pressure above 140/90 mm Hg or antihypertensive treatment before age 60 yr. Age at renal death in the propositus was defined as the start of renal replacement therapy. Median age at renal death of 23 offspring (11 male, 12 female) from families with a history of primary hypertension of the nonaffected parent was lower than that of 34 offspring (16 male, 18 female) from families without a known history of primary hypertension of the nonaffected parent, i.e., 49 yr (26 to 64) versus 54 yr (28 to 82) (P < 0.03). The data are consistent with the notion that genetic predisposition to primary hypertension is associated with an earlier onset of terminal renal failure in families with ADPKD.

Adult↗
PubMed1995

[Differential therapeutic aspects in treatment of obstructive sleep apnea syndrome].

We report the case of a 43-year-old man who suffered from obstructive sleep apnea with excessive daytime sleepiness and nocturnal sweating. His initial apnea index of 60/h improved under treatment with an Esmarch device. Apneas were totally suppressed by nCPAP application with a pressure of only 4 mb, but the patient rejected nCPAP therapy. After two years with the Esmarch device he reported increasing temporomandibular joint pain and Esmarch therapy had to be stopped. A cephalometric evaluation showed good prognosis for maxillomandibular advancement osteotomy, which was performed and which suppressed the apneas completely over a period of more than one year. Indication, surgical technique, and risks are discussed.

Adult↗
PubMed1995

[Nephroprotection by inhibition of the renin-angiotensin system--wish or reality?].

Angiotensin converting enzyme (ACE) inhibitors are used with increasing frequency in the treatment of hypertension in patients with chronic renal disease. In experimental models of chronic renal failure and, recently, in patients with diabetic nephropathy ACE inhibitors have also been shown to be effective on long-term administration in slowing the progression of renal failure. The exact mechanisms of this nephroprotective effect are not yet fully understood, but changes in hemodynamic parameters, a reduction of proteinuria and an inhibition of glomerular cell proliferation appear to be involved in preventing glomerulosclerosis.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

[Antihypertensive therapy in renal failure].

Hypertension can be a cause as well as a consequence of renal disease. Fluid overload or activation of the renin angiotensin system by glomerular ischemia leads to an elevation of systemic blood pressure in acute as well as chronic renal disease. Furthermore in the latter disorder an increased activity of the sympathetic nervous system as well as metabolic disorders contribute to hypertension. Accordingly antihypertensive therapy in patients with renal insufficiency is diverse. Additionally in chronic kidney disease one has to consider the variable effects of different antihypertensive drugs on intrarenal hemodynamics.

Antihypertensive Agents↗
PubMed1995

[Disorders of the circadian sleep-wake rhythm--diagnostic and therapeutic principles].

The most important circadian rhythm disorders are presented excluding jet lag syndrome and shift work. Clinical and psychological findings, pathophysiological principles and social consequences are discussed with reference to recent literature. The ICSD classification is reviewed critically and proposals for operationalisation of new diagnostic procedures are offered. The current therapeutic principles are described and it is attempted to develop a more systematic documentation of therapy aiming at the possibility of future outcome-comparison between the presently very heterogenic principles.

Biological Clocks↗
PubMed1994

Differential effects of extended sleep in narcoleptic patients.

The aim of the present study was to investigate the effects of extended night sleep on subsequent daytime sleep propensity in narcoleptic patients. The possible differentiation between REM and NREM sleepiness was of particular interest. Ten unmedicated narcoleptic inpatients (8 men, 2 women) aged 23-61 years (mean, 47.9 years) participated in this study. Adapting the patients to the hospital schedule (nocturnal sleep period from 22:00 to 6:00 h and ad lib, nap during daytime) for at least 2 weeks, we conducted a baseline PSG from 22:00 to 6:00 h and subsequent 5-trial daytime sleep recordings with naps (lying on the bed for 20 min light-out period) at 9:30, 11:30, 13:30, 15:30 and 17:30 h (the baseline condition: BC). After a 1-5 day interval, we conducted an extended PSG from 22:00 to 10:00 h. Subsequent to the extended PSG, we carried out 5-trial daytime sleep recordings. We adjusted the start time of the first nap trial at least 90 min after waking time and start time in the 5th nap trial before 19:00 h (the extended condition: EC). Mean TST was 417.0 min in the baseline PSG, and 595.2 min in extended PSG. Mean number of daytime naps per subject exhibiting a sleep latency shorter than 10 min was decreased in EC. Mean sleep latency in EC was significantly prolonged in comparison with that in BC. This prolongation of mean sleep latency per subject was positively correlated with S4 duration and % S4 obtained in the morning of the extended PSG (from 6:00 to wake time).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Human interleukin for DA cells or leukemia inhibitory factor is released by Vero cells in human embryo coculture.

In the light of the newly discovered implications of human interleukin for DA cells and leukemia inhibitory factor in embryology, we searched for the presence of this soluble cytokine in the supernatant of Vero cell coculture systems. Using a bioassay as well as a specific ELISA, we demonstrated that Vero cells are able to release large quantities of human interleukin for DA cells and leukemia inhibitory factor in the embryo-growing medium of such cocultures.

Animals↗
PubMed1994

Modafinil in diurnal sleepiness. A study of 123 patients.

The efficacy of modafinil, a psychostimulant drug acting on postsynaptic alpha-1 adrenergic receptors, as a treatment for excessive daytime sleepiness was studied in 123 patients. Subjects included 94 narcoleptic patients (76 with cataplexy), 23 hypersomnia patients and 6 patients with disrupted nocturnal sleep (DNS) and excessive daytime sleepiness (EDS). Clinical efficacy of the treatment on each symptom (EDS, cataplexy and DNS) was evaluated on a four-point scale from excellent to absent. The effectiveness of modafinil as a treatment for EDS was excellent in 17% of all patients, good in 63%, fair in 17% and absent in 3%. The incidence of side effects was rather low (14 of 123 patients) and most of them disappeared (11 patients) when doses were reduced.

Adolescent↗
PubMed1994

A simple technique for red blood cell removal in major ABO-incompatible bone marrow transplantation.

A simple technique for red blood cell (RBC) removal in major ABO-incompatible bone marrow transplantation is reported requiring two centrifugation steps, special blood bags and a mechanical device to separate the buffy coat from RBCs within the bag. In 42 transplantations an average of 84% of nucleated cells was recovered with an average contamination of 7.5 ml packed RBCs. The preparations were well tolerated in all patients whose isoagglutinin titers had not been reduced. Bone marrow engraftment was not significantly different from control groups.

Adult↗
PubMed1994

The gene amyE(TV1) codes for a nonglucogenic alpha-amylase from Thermoactinomyces vulgaris 94-2A in Bacillus subtilis.

We isolated the gene amyE(TV1) from Thermoactinomyces vulgaris 94-2A encoding a nonglucogenic alpha-amylase (AmyTV1). A chromosomal DNA fragment of 2,247 bp contained an open reading frame of 483 codons, which was expressed in Escherichia coli and Bacillus subtilis. The deduced amino acid sequence of the AmyTV1 protein was confirmed by sequencing of several peptides derived from the enzyme isolated from a T. vulgaris 94-2A culture. The amino acid sequence was aligned with several known alpha-amylase sequences. We found 83% homology with the 48-kDa alpha-amylase part of the Bacillus polymyxa beta-alpha-amylase polyprotein and 50% homology with Taka amylase A of Aspergillus oryzae but only 45% homology with another T. vulgaris amylase (neopullulanase, TVA II) recently cloned from strain R-47. The putative promoter region was characterized with primer extension and deletion experiments and by expression studies with B. subtilis. Multiple promoter sites (P3, P2, and P1) were found; P1 alone drives about 1/10 of the AmyTV1 expression directed by the native tandem configuration P3P2P1. The expression levels in B. subtilis could be enhanced by fusion of the amyE(TV1) coding region to the promoter of the Bacillus amyloliquefaciens alpha-amylase gene.

Amino Acid Sequence↗
PubMed1994

Hypoechoic perirenal fat in renal transplant recipients.

PURPOSE: To evaluate ultrasonographic (US) findings of morphologies, anatomic locations, and causes of hypoechoic rims that mimic disease and appear around native kidneys of asymptomatic renal allograft recipients. MATERIALS AND METHODS: Annual, routine abdominal US examinations of 170 renal allograft recipients were performed. US scans of 23 (13.5%) of these patients showed a hypoechoic rim. CT examination of the perirenal space was performed for 18 of these 23 patients to confirm the US findings. RESULTS: For 11 of these 18 patients, the hypoechoic rims on US scans corresponded to low-attenuation, septated perirenal fat on CT scans; for seven, the perirenal space appeared to be a homogeneous, fat-filled compartment. Low-attenuation fat in the perirenal space was separated by bridging septa. Patients with hypoechoic rims were significantly older than those without (57 years +/- 10 vs 48 years +/- 12, P = .001). CONCLUSION: Hypoechoic rims are frequently found in asymptomatic renal allograft recipients. They correspond not to disease but to low-attenuation perirenal fat divided into compartments by bridging septa.

Adipose Tissue↗