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Biomedical subjects

R Otto

Publications and source records attributed to R Otto.

At least 55 records · Page 3Linked to original sources
PubMed1989

Quantitative determination of verapamil and metabolites in human serum by high-performance liquid chromatography and its application to biopharmaceutic investigations.

A specific and sensitive high-performance liquid chromatographic method for the quantitative analysis of verapamil and N-desmethylverapamil in human serum is described. The analytes were extracted from serum using diethylether under alkaline conditions, followed by back extraction into dilute hydrochlorid acid for chromatographic analysis on a reversed-phase column with a mobile phase consisting of acetonitrile, water and perchloric acid at a flow rate of 1 l/min. The analytes were detected by fluorescence detection, the influence of temperature on retention is discussed. The method is linear, quantitative and reproducible for two calibration ranges in serum (2.5 ng/ml-100 ng/ml and 12.5 ng/ml-500 ng/ml) using peak area ratios analyte/internal standard for quantification. At ultimate sensitivity, concentrations down to 250 pg/ml could be assayed. The method was selective to 6 other metabolites of verapamil and common exogenous interferences. It was applicated to the serum samples of a comparative 120 mg - verapamil hydrochloride tablet single dose two-way cross-over study comprising 18 volunteers. The pharmacokinetic data for both formulations are presented.

Biopharmaceutics↗
PubMed1988

Evolution and regression of pancreatic calcification in chronic pancreatitis. A prospective long-term study of 107 patients.

Pancreatic calcifications are virtually pathognomonic of chronic pancreatitis and develop in up to 90% of patients with alcoholic chronic pancreatitis in series with long-term results. We investigated the natural course of pancreatic calcification in a prospective longitudinal study over the past 23 yr. All patients were studied at regular intervals with particular regard to etiology, clinical findings, surgery, pancreatic function, and pancreatic calcification visible by x-ray (e.g., film series in three projections centered on the pancreas). We evaluated the findings of 107 patients with x-ray documentation of pancreatic calcification in at least three film series over a period of 4 yr or longer. Eighty-four patients had alcoholic chronic pancreatitis (group A) and 23 patients had nonalcoholic chronic pancreatitis (group B). Four hundred seventy-two film series of group A and one hundred forty-two film series of group B were reviewed independently by two expert teams. Both series were graded according to a score system in terms of intensity and distribution of pancreatic calcification (correlation of grading r = 0.91). The duration of calcification averaged 10 yr in group A and 12.6 yr in group B. Similar dynamic changes of pancreatic calcification were noted in groups A and B. Chronologically, three phases of evolution could be distinguished. After an initial increase (phase 1), greater than 50% of cases reached a plateau of stationary calcification (phase 2). Approximately one-third of cases showed a marked decrease of calcification in late phases of chronic pancreatitis (phase 3). Dissolution of pancreatic stones was related primarily to duration of chronic pancreatitis (duration of calcification and marked pancreatic dysfunction), and occurred frequently (but not exclusively) in patients after ductal drainage procedures. These results indicate that spontaneous dissolution of pancreatic stones is a rather common biologic phenomenon. The factors responsible for dissolution of stones remain to be elucidated.

Adolescent↗
PubMed1987

[An incidental finding of renal cysts: routine occurrence or a finding deserving clarification?].

Since the introduction of new non-invasive diagnostic techniques such as abdominal ultrasound and computerized tomography, simple renal cysts are diagnosed with increasing frequency. Over 30% of patients over 50 years of age are found to have simple renal cysts of different size. A cystic renal mass may represent a simple renal cyst without clinical relevance, a cystic renal carcinoma, early evidence of polycystic kidney disease in a young patient, a rare cause of renal hypertension, a source of infection in a symptomatic patient (infected renal cyst), or a manifestation of an infectious disease (renal abscess, echinococcus cyst). The differential diagnosis and management of a cystic renal mass therefore remain a clinical problem. In the past, surgical exploration of a cystic renal mass was frequently performed. Today, modern diagnostic techniques such as ultrasound-guided percutaneous cyst puncture with cytological analysis of the cyst content, or computerized tomography, are considered the methods of choice. They are particularly useful in case of doubt about the dignity of a cystic renal mass. The determination of renal venous renin levels may be useful in differentiating the causal role of a renal cyst in a patient with hypertension. The management of a cystic renal mass depends on the underlying disease.

Diagnosis, Differential↗
PubMed1986

Subclavian aneurysm producing the subclavian steal syndrome.

An atherosclerotic aneurysm of the right subclavian artery causing subclavian steal syndrome is described. Complementary information obtained from digital subtraction angiography and computed tomography helped to establish a correct preoperative diagnosis.

Aneurysm↗
PubMed1985

Energy recycling by lactate efflux in growing and nongrowing cells of Streptococcus cremoris.

Streptococcus cremoris was grown in pH-regulated batch and continuous cultures with lactose as the energy source. During growth the magnitude and composition of the electrochemical proton gradient and the lactate concentration gradient were determined. The upper limit of the number of protons translocated with a lactate molecule during lactate excretion (the proton-lactate stoichiometry) was calculated from the magnitudes of the membrane potential, the transmembrane pH difference, and the lactate concentration gradient. In cells growing in continuous culture, a low lactate concentration gradient (an internal lactate concentration of 35 to 45 mM at an external lactate concentration of 25 mM) existed. The cell yield (Ymax lactose) increased with increasing growth pH. In batch culture at pH 6.34, a considerable lactate gradient (more than 60 mV) was present during the early stages of growth. As growth continued, the electrochemical proton gradient did not change significantly (from -100 to -110 mV), but the lactate gradient decreased gradually. The H+-lactate stoichiometry of the excretion process decreased from 1.5 to about 0.9. In nongrowing cells, the magnitude and composition of the electrochemical proton gradient was dependent on the external pH but not on the external lactate concentration (up to 50 mM). The magnitude of the lactate gradient was independent of the external pH but decreased greatly with increasing external lactate concentrations. At very low lactate concentrations, a lactate gradient of 100 mV existed, which decreased to about 40 mV at 50 mM external lactate. As a consequence, the proton-lactate stoichiometry decreased with increasing external concentrations of protons and lactate at pH 7.0 from 1 mM lactate to 1.1 at 50 mM lactate and at pH 5.5 from 1.4 at l mM lactate to 0.7 at 50 mM lactate. The data presented in this paper suggest that a decrease in external pH and an increase in external lactate concentration both result in lower proton-lactate stoichiometry values and therefore in a decrease of the generation of metabolic energy by the end product efflux process.

Energy Metabolism↗
PubMed1985

Control of oxygen uptake, microcirculation and glucose release by circulating noradrenaline in perfused rat liver.

The effect of noradrenaline on oxygen uptake, on periportal and perivenous oxygen tension at surface acini, on microcirculation and on glucose output were studied in isolated rat livers perfused at constant flow with Krebs-Henseleit-hydrogen carbonate buffer containing 5mM glucose and 2mM lactate. Noradrenaline at 1 microM concentration caused a decrease in oxygen uptake, while at 0.1 microM it led to an increase. Both high and low doses of noradrenaline decreased the tissue surface oxygen tension in periportal and - after a transient rise - in perivenous areas. Noradrenaline at an overall constant flow caused an increase of portal pressure and an alteration of the intrahepatic distribution of the perfusate: at the surface of the liver and in cross sections infused trypan blue led to only a slightly heterogeneous staining after a low dose of noradrenaline but to a clearly heterogeneous staining after a high dose. Both high and low doses of noradrenaline stimulated glucose release. All effects could be inhibited by the alpha-blocking agent phentolamine. In conclusion, control of hepatic oxygen consumption by circulating noradrenaline is a complex result of opposing hemodynamic and metabolic components: the microcirculatory changes inhibit oxygen uptake; they dominate after high catecholamine doses. The metabolic effects include a stimulation of oxygen utilization; they prevail at low catecholamine levels. The noradrenergic control of glucose release is also very complex, involving direct, metabolic and indirect, hemodynamic components.

Animals↗
PubMed1985

Surgery and granulocyte transfusions for life-threatening infections in chronic granulomatous disease.

We report two patients with chronic granulomatous disease (CGD) and life-threatening infections: a 10 10/12-year-old boy had Aspergillus fumigatus spondylitis with destruction of the 11th vertebral body and paravertebral abscess formation, and an 8 5/12-year-old boy had multiple Staphylococcus aureus hepatic abscesses with subphrenic abscess formation. Both patients failed to respond to intense antimicrobial therapy but showed a remarkable recovery following surgical drainage combined with granulocyte transfusions. These results suggest that antimicrobial therapy and surgical drainage followed by granulocyte transfusions may be the ideal mode of treatment for severe infections in patients with CGD.

Amphotericin B↗
PubMed1984

[The Mirizzi syndrome].

Three cases of Mirizzi's syndrome are reported, with special emphasis on differential diagnosis and preoperative evaluation. The syndrome consists of the triad cystic duct stone, inflammatory reaction and benign hepatic duct stenosis. Endoscopic retrograde cholangiography or percutaneous transhepatic cholangiography is mandatory for preoperative evaluation. Cholecystectomy with clearance of the bile duct is the treatment of choice.

Cholecystectomy↗
PubMed1984

[What does computer tomography and abdominal ultrasound studies accomplish in the staging of Hodgkin's disease?].

In a prospective series of 25 patients with early-stage Hodgkin's disease, abdominal assessment by computer tomogram and ultrasound was controlled by staging laparotomy. It was found that the probability of Hodgkin's disease increased with increasing diameter of the abdominal lymph nodes. 42% of the nodes between 16-20 mm in diameter had evidence of disease. Overall accuracy and specificity for the assessment of abdominal lymph nodes by CT and US was around 90%. Sensitivity was much lower than in other series, probably due to the fact that our patient sample was relatively small and consisted of patients in earlier stages with small lymph nodes. Assessment of lymph nodes by US is more, and assessment by CT less, dependent on individual factors. It is concluded that neither CT or US can replace staging laparotomy if precise information about abdominal lymph nodes is needed. Assessment of the spleen by CT and US is usually unreliable and needs histologic confirmation.

Adult↗