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Biomedical subjects

J Fritsch

Publications and source records attributed to J Fritsch.

At least 55 records · Page 3Linked to original sources
PubMed1995

Cholangiographic features in fibrosis and cirrhosis of the liver. Radiological-pathological correlation.

The cholangiographic features of intrahepatic bile ducts associated with cirrhosis or fibrosis are not well known. In order to achieve a radiological-pathological correlation, we studied nine livers with fibrosis or cirrhosis excised at autopsy. Cholangiograms were obtained within 24 hr after death from the nonfixed liver and multiple tissues samples were taken for histologic examination. Radiological data were interpreted by two independent investigators blinded to the clinical and histological findings. Cirrhosis (alcoholic in 4, posthepatitis in two) was observed in six livers, fibrosis (alcoholic in 2, posthepatitis in one) in three. No liver with fibrosis had cholangiographic abnormalities. In contrast, cholangiography of all livers with cirrhosis was abnormal. Abnormalities were a diminished arborization, a decrease of the distal opacification, an irregularity of caliber, and a tortuous course of the bile ducts. Histological study showed that the irregular and tortuous course were due to compression of the bile ducts by regenerative nodules. Furthermore, a thick fibrosis was organized around the bile ducts. In conclusion, fibrosis alone was not associated with cholangiographic abnormalities. In cirrhotic livers, intrahepatic bile ducts showed an irregular and tortuous course, a diminished arborization and a decrease of the distal opacification. These abnormalities were secondary to the presence of regenerative nodules and fibrosis organized around the bile ducts.

Autopsy↗
PubMed1995

Diagnosis and prognosis of AIDS-related cholangitis.

OBJECTIVE: To determine more precisely the clinical and biological characteristics of AIDS-related cholangitis, and to investigate prognostic variables of this disease. DESIGN: Retrospective clinical and prognostic study. SETTING: Biliary unit, Bicêtre Hospital, France. PATIENTS: HIV-positive patients (n = 52) referred to the unit between December 1986 and June 1993 for biliary symptoms leading to the suspicion of AIDS-related cholangitis, (42 men; 10 women; mean age, 37 +/- 8 years). INTERVENTION: Endoscopic retrograde cholangiopancreatography (ERCP) was performed in order to determine the cause of the biliary symptoms. MAIN OUTCOME MEASURE: Clinical features and evolution of the cholangitis. RESULTS: Among the 52 patients, 45 met the ERCP criteria of AIDS-related cholangitis (36 men; nine women). The diagnosis of cholangitis was strongly suggested by abdominal ultrasonography in 47% of the cases. ERCP showed papillary stenosis, diffuse cholangitis, extrahepatic cholangitis alone, and intrahepatic cholangitis alone in 60, 67, 7 and 27%, respectively. Endoscopic sphincterotomy was performed in 28 patients. Pain was relieved by sphincterotomy in nine patients, but the other clinical or biological features were not influenced. One-year and 2-year survival rates were 41 +/- 7% and 8 +/- 4%, respectively. Multidimensional analysis using a Cox model showed that a lymphocyte count > 500 x 10(6)/l was the only independent predictive factor of better survival. CONCLUSION: AIDS-related cholangitis is a disease which leads preferentially to papillary stenosis or diffuse abnormalities of the biliary tract. Prognostic factors depend on the stage of the HIV infection. Another diagnosis of cholestasis was found in approximately 15% of the patients who showed biliary symptoms.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Identification of an mRNA element promoting rate-limiting cleavage of the polycistronic puf mRNA in Rhodobacter capsulatus by an enzyme similar to RNase E.

We have identified an mRNA element that is involved in the initial cleavage of the pufBALMX mRNA species in Rhodobacter capsulatus. This endoribonuclease recognition site, the first to be identified in a bacterial species other than Escherichia coli, shows strong similarities to mRNA sequences cleaved by the endoribonuclease E in E. coli. The presence of an RNase E-like enzyme in R. capsulatus is further supported by in vitro cleavage of E. coli transcripts by R. capsulatus extracts at sites attributed to RNase E and by the cross-reaction of a polypeptide from R. capsulatus with antisera against E. coli RNase E. Our data provide evidence that mRNAs are degraded in different bacterial species by enzymes with similar recognition sequences and activities. We present a model that attributes the segmental differences in stability of the polycistronic puf transcript to a specific distribution of mRNA decay-promoting and mRNA decay-impeding elements.

Base Sequence↗
PubMed1995

Endoscopic sphincterotomy for suspected choledocholithiasis in patients with and without stones.

OBJECTIVE: To characterize a subgroup of patients treated with endoscopic sphincterotomy (ES) for a suspected common bile duct lithiasis (CBDL) that was not confirmed and to compare it with the subgroup with confirmed CBDL. METHODS AND RESULTS: Over 18 months, ES was successful in 245 consecutive patients (age 23-97, mean 75 yr, SE 17 yr) with suspected CBDL; 159 patients had CBDL (group 1), and 86 did not (group 2), as confirmed by CBD exploration. Fifty-nine percent of the patients in group 1 and 76.7% of the patients in group 2 had gallbladder in situ. Both groups were different for age (p < 0.001), prevalence of chronic alcoholism (p < 0.001), gallbladder in situ (p < 0.01), and gallbladder stones (p < 0.05). Patients from group 1 had two or more presenting symptoms suggestive of CBDL more often than patients from group 2 (p < 0.05), and pancreatitis was a more frequent presenting manifestation in group 2 (p < 0.0001). Overall morbidity and mortality were not different between groups, but acute cholecystitis developed in six patients from group 2 and in one patient from group 1 (p < 0.01). In a univariate analysis, only elevated alkaline phosphatase and a dilated common bile duct were positively discriminant for the diagnosis of CBDL; chronic alcoholism was negatively discriminant for the diagnosis of CBDL. In a multivariate analysis, only chronic alcoholism and a dilated bile duct were found to be independently discriminant. CONCLUSION: The risk of ES-related complications in the group without CBDL suggests that the selection of patients should be improved by a better use of preoperative criteria.

Adult↗
PubMed1994

Concentration-dependent modulations of potassium and calcium currents of rat osteoblastic cells by arachidonic acid.

We show that the voltage-gated K+ and Ca2+ currents of rat osteoblastic cells are strongly modulated by arachidonic acid (AA), and that these modulations are very sensitive to the AA concentration. At 2 or 3 microM, AA reduces the amplitude and accelerates the inactivation of the K+ current activated by depolarization; at higher concentrations (> or = 5 microM), AA still blocks this K+ current, but also induces a very large noninactivating K+ current. At 2 or 3 microM, AA enhances the T-type Ca2+ current, close to its threshold of activation, whereas at 10 microM, it blocks that current. AA (1-10 microM) also blocks the dihydropyridine-sensitive L-type Ca2+ current. Thus, the effect of AA on Ca2+ entry through voltage-gated Ca2+ channels can change qualitatively with the AA concentration: at 2 or 3 microM, AA will favor Ca2+ entry through T channels, both by lowering the voltage-gated K+ conductance and by increasing the T current, whereas at 10 microM, AA will prevent Ca2+ entry through voltage-gated Ca2+ channels, both by inducing a K+ conductance and by blocking Ca2+ channels.

Animals↗
PubMed1994

Activation of hyperpolarization and atypical osmosensitivity of a Cl- current in rat osteoblastic cells.

During whole-cell recording of rat osteoblastic cells with high-Cl- internal solutions, 10 sec hyperpolarizing jumps from 0 mV induce a slow inward current relaxation, which is shown to be carried by hyperpolarization-activated Cl- channels. This relaxation increases and becomes faster with stronger hyperpolarizations. It is insensitive to Cs+ ions but is blocked in a voltage-dependent manner by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) 1 mM and is reduced by 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) 0.1 mM. Cd2+ ions are potent blockers of this current, blocking completely above 300 microM. The amplitude of the Cl- current activated by a given hyperpolarization increases during the first 10-20 min of whole-cell recording. This evolution and the fact that some recently cloned Cl- channels have been reported to be activated both by hyperpolarization and by external hyposmolarity led us to investigate the effects of external osmolarity. Reducing the external osmolarity induces a large Cl- current. However, this hyposmolarity-induced Cl- current and the hyperpolarization-activated Cl- current are shown to be distinct; 1,9-dideoxy forskolin selectively blocks the hyposmolarity-activated current. We show that the hyperpolarization-activated Cl- current is osmosensitive, but in an unusual way: it is reduced by external hyposmolarity and is increased by external hyperosmolarity. Furthermore, these modulations are more pronounced for small hyperpolarizations. The osmosensitivity of the hyperpolarization-activated Cl- current suggests a mechanosensitivity (activation by positive external pressure) that is likely to be physiologically important to bone cells.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1994

Dual modulation of the L-type calcium current of rat osteoblastic cells by parathyroid hormone: opposite effects of protein kinase C and cyclic nucleotides.

Using whole-cell voltage-clamp recording of rat osteoblastic cells, we show that PTH-(1-34), known to stimulate protein kinase C (PKC) and adenylate cyclase, has a dual effect on the L-type calcium current. It induces a long-lasting increase and a superimposed reversible decrease, which can be separated by repeating hormone applications. The stimulatory effect is the only effect induced by the (3-34) fragment, able to stimulate PKC but unable to stimulate adenylate cyclase. The L current is stimulated by an active phorbol ester and is reduced by permeable analogues of cyclic AMP. Thus, the effect of PTH-(1-34) can be explained by the opposite effects of PKC and cyclic AMP. Dibutyryl cyclic GMP reduces the L current even more potently than dibutyryl cyclic AMP. The above modulations are all voltage-insensitive. These results led us to reinvestigate the effects of some vitamin D3 metabolites known to stimulate PKC and/or guanylate cyclase, and previously reported to affect the voltage-sensitivity of the L current. We only detected voltage-insensitive effects.

Animals↗
PubMed1994

Management of clinically relevant bleeding following endoscopic sphincterotomy.

We report here on our experience of clinically relevant bleeding after endoscopic sphincterotomy (ES). Relevant bleeding was defined by the occurrence of (a) hematemesis or melena and (b) at least a two-point drop in hemoglobin, with no other bleeding source on endoscopy. These two criteria were met in 16 patients between 1983 and 1992. They represented 0.65% of all ES procedures performed during this period. Bleeding occurred immediately after ES in five cases, and was delayed in 11 cases from one to eight days (mean two days). Patients were retrospectively classified into three groups according to the severity of bleeding and subsequent clinical management. In six cases (group 1), bleeding developed slowly without shock and stopped spontaneously. In five cases (group 2), bleeding developed rapidly with melena and a drop in hemoglobin, but without shock. These patients were successfully managed with sclerotherapy without any further complications. The five patients in Group 3 had brisk bleeding with hematemesis and shock. Endoscopic hemostasis could not be performed; emergency arteriography disclosed active bleeding in four patients, and embolization of the gastroduodenal artery was performed. Bleeding stopped in all patients. Billroth II anastomosis appeared to be the only factor associated with an increased risk of clinically relevant bleeding. It was possible to control bleeding following ES using endoscopic or angiographic hemostasis, surgery being avoided in all cases.

Adult↗
PubMed1994

Cloning of a gene involved in rRNA precursor processing and 23S rRNA cleavage in Rhodobacter capsulatus.

In Rhodobacter capsulatus wild-type strains, the 23S rRNA is cleaved into [16S] and [14S] rRNA molecules. Our data show that a region predicted to form a hairpin-loop structure is removed from the 23S rRNA during this processing step. We have analyzed the processing of rRNA in the wild type and in the mutant strain Fm65, which does not cleave the 23S rRNA. In addition to the lack of 23S rRNA processing, strain Fm65 shows impeded processing of a larger 5.6-kb rRNA precursor and slow maturation of 23S and 16S rRNAs from pre-23S and pre-16S rRNA species. Similar effects have also been described previously for Escherichia coli RNase III mutants. Processing of the 5.6-kb precursor was independent of protein synthesis, while the cleavage of 23S rRNA to generate 16S and 14S rRNA required protein synthesis. We identified a DNA fragment of the wild-type R. capsulatus chromosome that conferred normal processing of 5.6-kb rRNA and 23S rRNA when it was expressed in strain Fm65.

Bacteriochlorophylls↗
PubMed1994

[Cardiopulmonary capacity in patients before and after prosthetic valve replacement].

In this study we wanted to investigate if noninvasive cardiopulmonary exercise testing can be securely, accurately applied in patients with acquired cardiac valve disease pre- and postoperatively with any convenience. Furthermore, we looked if the cardiopulmonary exercise capacity (anaerobic threshold, etc.) was improved postoperatively (3 and 6 months) in 15 patients suffering from severe mitral valve disease as compared to the preoperative condition. The symptom-limited cardiopulmonary exercise testing was performed on a bike in a semi-supine position using a ramp program (+20 W/min). The following parameters were continuously monitored, and the breath-by-breath gas exchange values documented: cardiocirculatory parameters (heart rate; blood pressure; surface ECG; exercise capacity in Watts); gas-exchange parameters (O2-uptake VO2; CO2-production VCO2; respiratory anaerobic threshold VO2 AT; gas-exchange ratio VCO2/VO2; O2-pulse VO2/HR; aerobic capacity delta VO2/delta WR) and ventilatory parameters (respiratory rate; tidal volume Vt; minute ventilation VE; equivalent for O2: VE/VO2 and CO2: VE/VCO2). The 155 cardio-pulmonary exercise tests in 115 patients were practicable, safe (no emergency case) and accurate. In 100 patients late postoperatively (68.3 +/- 53.0 -102.9 +/- 41.2 months) after aortic or mitral valve replacement or both without signs of significant hemolysis or prosthetic valve dysfunction the NYHA classification was too imprecise to characterize the actual exercise capacity of the patients (e.g., NYHA class II: Weber class B to E). Patients with aortic valve prosthesis had a significantly better anaerobic threshold (57.4 +/- 19.1% pred. value max. VO2) as compared to those with mitral valve replacement (mean: 35.9% pred. value max. VO2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Methodologic aspects of modern, computerized ergospirometry (CPX): ramp program, constant workload test and CO2 rebreathing method].

The cardiopulmonary exercise testing (CPX) is a non-invasive method for the evaluation of the cardiopulmonary exercise capacity. Based upon the recent technical progress in gas analysers and personal computers today it is possible to perform CPX with acceptable time consumption, high practicability and high reproducibility of the results in many clinical areas. CPX is realized on a bike or on a treadmill. In bicycle CPX a ramp program (increase of x watts per minute) or a constant workload test (p.e. with 75% of the watts at anaerobic threshold) are performed. Furthermore, an estimation of the cardiac output using CO2-rebreathing method can be realized during a ramp program or a constant workload test. In this paper, also the CPX parameters of the ramp program, the constant workload test and the CO2-rebreathing method are defined and explained. The normal values of CPX are dependent of age, sex, body weight and exercise program. This should be kept in mind in interpreting the measured CPX data. Additionally, the performance of a routine CPX will be reported. Furthermore, the accuracy of the CPX parameters and the potential influences on the data will be discussed. Finally, problems during measurements and their analysis will be clarified.

Carbon Dioxide↗
PubMed1994

[Cardiopulmonary capacity of patients with congenital heart defects in childhood, adolescence and adulthood].

Cardiopulmonary exercise capacity is a significant criterion of life quality. The evaluation of the exercise capacity is important to answer patient-questions concerning every day activity, choice of profession, sports-activity etc. We performed cardiopulmonary exercise testing in 38 patients (age 33.6 +/- 12.0 years, 18 women, 20 men) with different congenital heart disease (5 after surgical repair of tetralogy of fallot, 2 after Mustard-operation in transposition of the great arteries (TGA), 1 single ventricle, 14 atrial septal defect (ASD), 8 ventricular septal defect (VSD), 8 pulmonary valve stenosis (PS)) during outpatient routine control. All tests were performed on upright bicycle with continuous ramp program of 20 Watt increase/minute. Ventilatory values as O2-uptake, CO2-production, minute ventilation (VE) were measured breath-by-breath. Max. VO2 was reduced as average value for every patient group (tetralogy of fallot 60.2 +/- 20.3% pred., TGA 53.0 +/- 0.0% pred., single ventricle 35% pred., closed ASD 71.9 +/- 23.8% pred., ASD 62.7 +/- 30.0% pred., VSD 64.1 +/- 11.7% pred., PS 73.2 +/- 16.0% pred.). Anaerobic threshold was reduced in tetralogy of fallot (35.9 +/- 12.2% pred. max. VO2) and in single ventricle (28.3% pred. max. VO2). In comparison with clinical classification of exercise capacity we found for max. VO2 differences in 23/38 patients. 22/23 patients reported no exercise limitation but had reduced max. VO2. One patient had a normal max. VO 2 but complaints of exercise dyspnoea. For anaerobic threshold 18/38 patients had discrepancies in objective and subjective estimation of their exercise capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗