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Biomedical subjects

M Sauer

Publications and source records attributed to M Sauer.

At least 55 records · Page 3Linked to original sources
PubMed1997

Congenital axonal neuropathy caused by deletions in the spinal muscular atrophy region.

Three newborn siblings presented with generalized weakness, asphyxia, facial diplegia, and external ophthalmoplegia. Electrophysiological testing showed inexcitability of motor and sensory nerves and myographic signs of denervation. Nerve biopsies and postmortem examination showed loss of myelinated fibers and axonal damage in sensory and mixed nerves. Many spinal motor neurons were chromatolytic although their number was normal. Molecular genetic investigations revealed a homozygous deletion of the survival motor neuron (SMN) gene and a loss of markers Ag1-CA and C212 in the paternal haplotype. These findings are consistent with the diagnosis of an unusually severe type of spinal muscular atrophy. Given the large extent of the deletion, it must be considered that the unusual severe phenotype with involvement of brainstem nuclei and afferent nerves might also be due to changes of yet unknown genes neighboring the SMN gene.

Axons↗
PubMed1997

Ventricular shunt infection and meningitis due to Bacillus cereus.

Non-anthrax Bacillus species are usually considered to be contaminants if found in clinical specimens. Only a few patients with systemic infections due to Bacillus cereus are reported. We present the case of a 18-month old boy with a primitive neuroectodermal tumor (PNET) in the brainstem and obstructive hydrocephalus that required an outlying and subsequently a ventriculoperitoneal drain. Following contamination at the site of entry of the external drain, shunt infection and meningitis with Bacillus cereus developed. Antibiotic treatment with vancomycin failed to eliminate the bacterium from the cerebrospinal fluid, so the shunt system had to be removed. Explantation of the shunt and addition of fosfomycin to the antibiotic regimen resulted in a complete cure of the infection.

Bacillaceae Infections↗
PubMed1996

Outpatient Reversal of Sterilization with Laparoscopically Placed Titanium Staples

We assessed the feasibility of performing outpatient reanastomosis of the fallopian tubes using titanium staples. Twelve women underwent routine infertility evaluation followed by laparoscopic tubal anastomosis. After preparation of the fallopian tubes, cannulation was performed proximally by hysteroscope or distally with a 3F catheter stent. The mesosalpinx was approximated with titanium staples. Circumferential staples (3-4) were placed around the stented tube to approximate the tubal muscularis. Patency was documented intraoperatively by chromotubation. Mean operating time was 130 minutes (range 90-170 min). Patients were generally discharged within 6 hours of surgery. Bilateral anastomosis was performed in nine women and unilateral anastomosis in three due to inadequate tubal length. Preliminary follow-up with hysterosalpingogram at 6 months revealed 80% tubal patency, and four women are currently pregnant. We suggest that laparoscopic reversal of sterilization is a viable alternative to more traditional methods and can be performed in an outpatient setting.

Journal Article↗
PubMed1996

Radiotherapy for carcinomas of the head and neck in elderly patients.

BACKGROUND/AIM: One fourth of patients with carcinomas of the head and neck present at the age of > or = 75 years, but tolerance and outcome of radiotherapy in this population is unknown from the literature. Our aim was to assess the overall survival rate in comparison to the survival probability of the normal population, and to document the efficacy of local treatment. PATIENTS AND METHODS: From 1980 to 1993, 75 patients aged 75 years or more (median 78.5 years) were treated with curative intent for carcinomas of the head and neck excluding the nasopharynx, paranasal sinuses, salivary glands and lips. Seventeen received postoperative radiotherapy, 58 were treated with radiotherapy alone. Early stage disease (T1 or T2 N0) was present in 26 patients, 27 patients presented with stage T3 and T4 any N. Eight patients received hyperfractionated radiotherapy to 74.4 Gy with 1.2 Gy twice daily. All others were treated with 1.8 to 2 Gy to a median total dose of 70 Gy in 6 to 8 weeks. RESULTS: All but 6 patients completed radiotherapy. Local control at 3 years was 83% for early stage disease, and 39% for T3 and T4 tumors. Actuarial overall survival was 30% at 5 years, compared to 63% for age-matched male and 69% for female Swiss residents, respectively. The survival curve of the patients followed the curve of the normal population after a rapid drop in survival within the first 2 years. Median time to local relapse was 3 and 4 months, respectively, for early and advanced stages, and 6 months for glottic carcinomas. Except 1 case of bone necrosis, there was no severe late toxicity observed. CONCLUSION: Although retrospective, the results suggest that the ultimate outcome in elderly patients with carcinomas of the head and neck is comparable to the course of the disease in younger patients.

Actuarial Analysis↗
PubMed1992

[Guillain-Barré syndrome in childhood. Characteristic course and therapeutic possibilities].

The incidence of the GBS in childhood is significantly lower than in adults. The clinical course may be equally severe, 10-25% of the affected children requiring artificial ventilation. Besides respiratory insufficiency, cardial arrhythmias are a major threat to the patients' lives. However, eventually more than 90% of the children recover completely. Controlled studies on the efficacy of therapeutic measures have been performed only in adults. To children their results should be transferred with caution. Steroids are of no value in the acute disease. However, they should be tried when progression for more than 4 weeks suggests the diagnosis of CIDP. Plasmapheresis is beneficial in CIDP and severe GBS; in GBS the time for weaning from the respirator and for achieving independent ambulation is significantly reduced. Recent studies have demonstrated that intravenous immunoglobulins can be equally effective. However, the administration of immunoglobulins in less severe cases should at present be reserved to a controlled study.

Adolescent↗
PubMed1992

[Nuclear magnetic resonance tomography and differential diagnosis of Hallervorden-Spatz disease].

The case of a 15 year old male patient with progressive dystonia, dysarthria and dementia is presented. No diagnosis could be found on clinical grounds. Low field MRI (0.23 T) demonstrated bilateral necrosis in the globus pallidus of clinically unknown etiology. Only high field imaging (2.0 T) revealed a pattern of lesions which is supposed to be specific for Hallervorden-Spatz disease (HSD): bilateral symmetrical decreased signal intensity in the globus pallidus secondary to the T2* effect of paramagnetic substances, principally iron. The neuroradiological differential diagnosis and pathognomonic signs of HSD are discussed.

Adolescent↗
PubMed1990

Sodium entry routes in principal and intercalated cells of the isolated perfused cortical collecting duct.

Transmembrane sodium transport pathways were studied in principal and intercalated cells of the isolated perfused rabbit cortical collecting duct. Intracellular electrolyte concentrations in individual collecting duct cells were measured by electron microprobe analysis during blockage of basolateral Na-K-ATPase by ouabain and simultaneous inhibition of sodium entry across the apical and/or basolateral cell membrane. In principal cells the ouabain-induced rise in cell sodium concentration could only partially be blocked by amiloride (10(-4) mol/l) in the perfusion fluid. Amiloride (10(-3) mol/l) added to the bathing solution produced a further, significant reduction of sodium influx. In principal cells the ouabain-induced increase in sodium concentration was completely prevented by amiloride in the perfusion solution in combination with omission of sodium from the peritubular bathing solution. In intercalated cells ouabain caused a less pronounced increase in sodium concentration than in principal cells. Neither amiloride in the perfusate, nor amiloride in both bathing and perfusion solution, significantly reduced the ouabain-induced rise in intercalated cell sodium concentration. These results indicate that in principal cells amiloride-sensitive sodium channels constitute the predominant pathway for sodium entry across the apical cell membrane. In addition, substantial amounts of sodium enter principal cells across the basolateral cell membrane, probably via Na-H exchange. Finally, the data suggest that in intercalated cells sodium channels and the Na-H exchange are sparse or even absent.

Amiloride↗
PubMed1990

Sequence of the fhuE outer-membrane receptor gene of Escherichia coli K12 and properties of mutants.

The fhuE gene of Escherichia coli codes for an outer-membrane receptor protein required for the uptake of iron(III) via coprogen, ferrioxamine B and rhodotorulic acid. The amino acid sequence, deduced from the nucleotide sequence, consisted of 729 residues. The mature form, composed of 693 residues, has a calculated molecular weight of 77,453, which agrees with the molecular weight of 76,000 determined by polyacrylamide gel electrophoresis. The FhuE protein contains four regions of homology with other TonB-dependent receptors. A valine to proline exchange in the 'TonB box' abolished transport activity. Phenotypic revertants with substitutions of arginine, glutamine, or leucine at the valine position exhibited increasing iron-coprogen transport rates. Point mutations resulting in the replacement of glycine (127) in the second homology region with either alanine, aspartate, valine, asparagine or histidine exhibited decreased transport rates (listed in descending order). A truncated FhuE protein lacking 24 amino acids at the C-terminal end was exported to the periplasm but failed to be inserted into the outer membrane.

Amino Acid Sequence↗
PubMed1990

[Behavior of pO2 on rabbit small intestine serosa, measured with the Clark electrode in different models of intestinal ischemia].

The pO2 on the surface of the small intestine serosa was measured on an isolated small intestine loop of the rabbit after synchronistic arterial and venous ligature of the mesenterium, after synchronistic arterial starvation and venous ligature, and after torsion of the mesenterium. The measurements of the pO2 were carried out by means of a Clark-electrode. Different periods for the decrease of the pO2 to zero Torr were shown in the different models of intestinal ischemia. Only the difference between the synchronistic arterial and venous ligature and torsion was statistically significant.

Animals↗
PubMed1990

[Results of transabdominal chemical sympathectomy of the lower extremities directed by computer tomography].

The authors evaluated 47 transabdominal lumbar sympatectomies by ethyl alcohol with a control by computer tomography in surgically unsolved disorders in the passage through lower extremity arteries. In four fifths of the patients there was an increase in ischaemia manifestations, in one fifth there was no improvement. No substantial difference was found between the results of sympatectomy in diabetic and nondiabetic patients. The method should be applied sooner than a cutaneous ischaemic defect develops.

Adult↗
PubMed1989

Effect of ouabain on electrolyte concentrations in principal and intercalated cells of the isolated perfused cortical collecting duct.

Sodium, phosphorus, chloride and potassium concentrations were measured by a new method in individual principal and intercalated cells in the cortical collecting duct in vitro. Electron microprobe analysis was applied to freeze-dried cryosections of the isolated perfused rabbit cortical collecting duct. Cell analyses were performed under control conditions and after addition of ouabain to the bath. Under control conditions similar sodium, potassium, chloride, and phosphorus concentration (means +/- SEM) were observed in principal (10.0 +/- 0.6, 126.5 +/- 2.7, 24.6 +/- 1.0, and 121.5 +/- 3.5 mmol/kg wet weight, respectively) and intercalated cells (9.0 +/- 0.9, 127.1 +/- 4.2, 27.4 +/- 1.8, and 118.7 +/- 4.9 mmol/kg wet weight, respectively). In principal cells ouabain (10 min) caused an increase in sodium and chloride concentrations by 104 and 13 mmol/kg wet weight, and a decrease in potassium and phosphorus concentrations by 106 and 32 mmol/kg wet weight. These changes in cell element concentrations can be ascribed to an exchange of intracellular potassium against extracellular sodium and to cell swelling due to influx of extracellular fluid. The effects of ouabain on intercalated cells were far less pronounced than on principal cells. This different susceptibility to ouabain of principal and intercalated cells can be ascribed to differences in active and passive transmembrane ion transport pathways.

Animals↗
PubMed1989

[Hancock pericardial prosthesis. Intrinsic dysfunctions].

The frequency of primary dysfunction of 432 Hancock pericardial bioprosthesis was evaluated during a mean follow-up period of 53.1 months per patient. This frequency was 3.20% valve-year in mitral valve prosthesis and 0.92% valve-year in aortic valve prosthesis. Only one case of calcification was noted. Dysfunction was usually due to tearing of one or several pericardial cusps (25 cases), occasionally to tissue retraction (4 cases). Pathological examination of the explanted valves showed fibrin formation followed by organization into fibrous tissue in the host, retracting or fragilizing the pericardial valvular tissue. A preliminary study of the same group had led to discontinuation of Hancock prosthesis. The long follow-up period makes it possible to compare the results obtained with those of pericardial prosthesis of the same generation, to stress the need for echocardiographic monitoring of the implanted valves and to hope that new techniques of pericardial valve fitting will improve the mechanical reliability of prosthesis which, from the point of view of thrombogenesis and haemodynamics, have unquestionable advantages.

Adolescent↗
PubMed1989

[Primary failure of pericardial valvular heterografts].

From July 1981 to October 1984, 79 Hancock pericardial valves were implanted in 74 patients surviving the hospital period and with a mean age of 64.2 years. Fifty-two patients underwent aortic valve replacement, 16 had mitral valve replacement, 5 bad a double replacement and 19 associated procedures were performed. The mean survival is 48 months. Until 1st June 1987, 11 primary failures have required reoperation (14.9%), 4 in the mitral position (4.6% patient-years), 7 in the aortic position (3.01% patient-years). The time to reoperation was 48.4 months for the aortic orifice and 36.5 months for the mitral orifice. The lesions most frequently encountered were tears (7 cases), calcifications (5 cases) and stretching of valvular tissue (2 cases); two patients died during the postoperative phase of this operation. Despite the small number of patients followed, this series demonstrates of high incidence of dysfunction due to primary tissue degeneration as, after the 5th year, the actuarial rate of absence of primary lesion is 85.3 +/- 8% with no significant difference between the aortic and the mitral orifices, although dysfunction appears to occur more rapidly in mitral prostheses. These results are much less favourable than those obtained with Ionescu bioprostheses in the aortic position of those obtained with porcine bioprostheses in either position. This justifies very regular clinical and echocardiographic follow-up of patients with Hancock pericardial valvular heterografts.

Actuarial Analysis↗
PubMed1989

Element composition of tubule cells in the inner stripe of the renal outer medulla.

To obtain further insight into renal medullary function, element concentrations were determined in individual tubule cells of the outer medulla in the rat kidney using electron microprobe analysis on freeze-dried cryosections. In the cells of the thick ascending limb of Henle's loop the Na, P, Cl, and K concentrations (means +/- SEM) were: 9.5 +/- 0.6, 158.4 +/- 6.2, 25.6 +/- 1.2, and 135.3 +/- 4.8 mmol/kg wet weight, respectively. While similar Na, P, and K concentrations were observed in light and dark cells of the medullary collecting duct, Cl was markedly higher--55.0 +/- 2.8 mmol/kg wet weight--in the dark cells. The electrolyte concentrations of the thick ascending limb cells seen in the present study are in good agreement with ion activities reported for the isolated perfused thick ascending limb. The low cell Na and Cl concentrations provide a favorable driving force for passive cell entry of Na, Cl, and K across the apical membrane via the Na-2Cl-K cotransporter even at low tubule fluid NaCl concentrations. Although in hydropenic rats interstitial tonicity of the inner stripe is above isotonicity, electrolyte concentrations of inner stripe cells did not differ from those obtained in cortical tubule cells. This finding suggests that, similar to papillary cells, osmoadaptation of outer medullary cells is, at least partially, accomplished by organic osmolytes.

Animals↗
PubMed1989

[Studies of myocardial metabolism using P-31-NMR spectroscopy and a simple heart perfusion model of slaughtered animals--an approach to avoiding in vivo animal experiments].

In research cardiology large numbers of in vivo animal experiments, mostly with dogs or pigs, are necessary. It was the aim of this study to test a simple in vitro perfusion heart model from swine harvested in the slaughterhouse as a potential substitute for in vivo animal studies. 32 unselected hearts of slaughterhouse swine after 10 to 15 min of warm ischemia were subjected to reperfusion with warm oxygenized blood and were examined for mechanical recovery, which occurred in 56%, increasing to 95% if primarily using only hearts that were in relaxation. In 21 of selected relaxed heart models the energy phosphate pattern as an index of viability was measured by P-31 MRS on a 4.7 Tesla NMR tomograph in 37 experimental runs with the following perfusion protocols: 1) immediate cardioplegia with cold Bretschneider or Collins solution, transportation under cooling, MRS after approximately 1 h; 2) immediate cardioplegia, transportation, reperfusion with oxygenated warm blood, MRS; 3) immediate blood perfusion with genuine fresh arterial blood from the slaughterhouse, cold plegia perfusion, transportation, MRS; 4) immediate blood perfusion with transportation MRS; 4) immediate blood perfusion with genuinefresh arterial blood, cold plegia perfusion, transportation, reperfusion with oxygenated warm blood, MRS during reperfusion; 5) An experimental pig heart was made plegic in vivo and reperfused with oxygenated warm blood during MRS as reference.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗