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Biomedical subjects

A Ulrich

Publications and source records attributed to A Ulrich.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Palliative therapy of esophageal carcinoma].

For palliative endoscopic treatment of malignant dysphagia many different techniques are practiced. The differentiated usage of all techniques depending on the characteristics of the tumor leads to a good result with favorable costs. The following differentiated palliative regimen is presented: in the cervical part of the esophagus laser therapy or stent implantation are used, depending on the type of tumor growth. In the center section and the distal part of the esophagus usually palliative endoscopic pertubation is performed. If the stenosis is very soft and short a stent is implanted as alternative. In the gastroesophageal part flexible stents achieve the best results. Alternative laser therapy can be used.

Aged↗
PubMed1998

[Portal hypertension and variceal bleeding: shunt in concomitant or general prehepatic block].

Thrombosis of the portal system should be ruled out in all patient with esophagogastric varices. Such patients with no evidence of concomitant liver disease and with a high risk of rebleeding (e.g. gastric varices, low platelet counts, endoscopic criteria) should be referred to decompressive shunt surgery. The type of shunt is dictated by the patent segments of the portal system. Splenectomy should be avoided. The results show a low operative mortality, a zero encephalopathy and a low rebleeding rate. Patients with prehepatic thrombosis and liver cirrhosis represent a more severe problem since the risk and mortality of variceal hemorrhage is high and on the other hand TIPS procedure and liver transplantation may be impossible. In case of a high risk of rebleeding or endoscopic therapy failure we advocate surgical shunting as the risk of encephalopathy appears to be low when portal flow diversion already exists.

Adolescent↗
PubMed1998

[Value of diagnostic laparoscopy in primary malignant liver tumors].

The advent of new imaging modalities such as CT-AP and MRT has markedly improved the diagnosis and staging of primary liver tumors and will change the diagnostic impact of laparoscopy. Diagnostic laparoscopy in this retrospective study was not found to add information in regard to tumor staging and resectability, and there was no clear benefit by avoiding diagnostic laparotomies when all imaging and biopsy techniques available were used preoperatively. Therefore, we advocate the use of diagnostic laparoscopy only in selected cases suspicious for superficial small tumor lesions and cirrhosis with impact on the treatment modality.

Adult↗
PubMed1997

Serial electrocardiogram changes in acute tricyclic antidepressant overdoses.

OBJECTIVES: To describe the changes over time of the QRS interval and terminal 40-msec QRS frontal axis (T40-ms) in patients with acute tricyclic antidepressant poisoning, to identify clinical factors and treatment associated with these changes, and to determine if patients with tricyclic antidepressant-related complications (seizures and/or arrhythmias) had differences in such serial electrocardiogram (ECG) changes when compared with patients without complications. DESIGN: Prospective, observational, cohort study. SETTING: Emergency departments of community and university-based hospitals in Massachusetts that consulted a large regional poison center. PATIENTS: Thirty-six patients who presented with an acute ingestion (< 24 hrs) of a tricyclic antidepressant, who had at least three electrocardiograms in the first 8 hrs and serial ECGs until discharge, and who had a peak tricyclic antidepressant concentration of > 300 ng/mL. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The maximal limb-lead QRS interval and T40-ms axis were measured manually in all ECGs. The maximum recorded QRS interval occurred at the time of presentation for 24(80%) of 30 patients whose QRS was > or = 100 msecs and a median time of 3 hrs (range 1 to 9) for the other six patients. The maximum recorded T40-ms axis occurred at the time of presentation for 31(86%) of 36 patients and at a median time of 3 hrs (range 1 to 5) for the remaining five patients. The minimum QRS interval observed remained > or = 100 msecs in 15 patients (range 100 to 140 msecs) and decreased to < 100 msecs in 15 patients. The median time from presentation to the first ECG with a QRS < 100 msecs was 20 hrs (range 1 to 153) in those 15 patients. There were no significant differences in clinical characteristics and treatment (including sodium bicarbonate therapy) between the two groups. The minimum recorded T40-ms remained > or = 120 degrees in 30 patients and decreased to < 120 degrees in six patients. The median time from presentation until the first ECG with a T40-ms axis < 120 degrees was 13 hrs (range 2 to 30) for the six patients. All ECG measurements were greater and remained abnormal for a significantly longer duration in those patients who developed seizures and/or ventricular arrhythmias. These two ECG parameters demonstrated ongoing changes and persistent abnormalities despite clinical improvement in all patients except one. CONCLUSIONS: The conduction abnormalities seen in severe tricyclic antidepressant toxicity vary widely in the time observed for resolution of these abnormalities and sometimes remain persistently abnormal. All ECG parameters were significantly more abnormal in those patients who developed seizures and/or arrhythmias. Clinical improvement occurred both before and during these ECG changes.

Acute Disease↗
PubMed1996

Influence of Bovine Slurry Deposition on the Structure of Nodulating Rhizobium leguminosarum bv. viciae Soil Populations in a Natural Habitat.

The population of nodulating R. leguminosarum bv. viciae in soil from a grass-covered valley area which had been used for bovine slurry deposition over a period of 5 years was analyzed. For these studies, a rapid and reproducible method based on enterobacterial repetitive intergenic consensus (ERIC)-PCR was applied to identify Rhizobium strains which had infected pea nodules. Soil samples were taken from different areas and further analyzed in plant tests to determine the impact of the application of slurry (polluted or nonpolluted), the slope position (summit or toe), and exposure (north or south). After comparison of all PCR fingerprint patterns, 24 strain groups were defined. Some strain groups from the nonpolluted soil were suppressed in the polluted samples, and new strain groups were detected in the slurry-polluted soil. After analyzing relationships between the strain groups, we determined the influences of local factors on the nodulating R. leguminosarum bv. viciae population. We show that one of those local parameters, slope position, had significantly greater impact on the composition of the Rhizobium population than the presence of slurry.

Journal Article↗
PubMed1996

Detection of disturbed autoregulation of the peripapillary choroid in primary open angle glaucoma.

BACKGROUND AND OBJECTIVE: This study is concerned with perfusion-pressure videoangiographic investigations, performed by combining oculo-oscillo-dynamography and videoangiography. Perfusion-pressure videoangiography permits an evaluation of local vascular resistance in the choroid relative to ciliary perfusion pressure. PATIENTS AND METHODS: Twelve healthy subjects, 21 patients with primary open angle glaucoma (POAG), and 27 patients with ocular hypertension were examined. RESULTS: Perfusion-pressure videoangiograms revealed that the peripapillary choroid (nasal main ciliary artery) filled at distinctly lower perfusion pressures than the paramacular region (temporal main ciliary artery) in all 12 healthy subjects, with a perfusion pressure difference of 12.5 +/- 4.9 mm Hg. In the 21 patients with POAG, the perfusion pressure difference between the beginning of peripapillary and paramacular perfusion was as small as 3.7 +/- 4.5 mm Hg. In the 27 patients with ocular hypertension, the perfusion pressure difference between the two circulatory regions was almost as high as in the healthy subjects. CONCLUSIONS: These examinations showed that (1) there exists efficient autoregulation in the peripapillary choroids of healthy subjects, (2) autoregulation is diminished or even absent in POAG, and (3) autoregulation is normal, increased, or slightly reduced in ocular hypertension.

Adolescent↗
PubMed1995

Laparoscopic colorectal surgery--are we being honest with our patients?

PURPOSE: A survey was undertaken to assess the impact of laparoscopy on the practice of colorectal surgery. METHODS: A total of 1,520 questionnaires were mailed to all members of the American Society of Colon and Rectal Surgeons; 635 (42 percent) surgeons responded, 50 percent, and indicated that one questionnaire represented their entire group practice. RESULTS: Two hundred seventy-eight (47 percent) respondents currently perform laparoscopic colorectal surgery; 62 percent (171) use the laparoscope for < or = 20 percent of their bowel resections. Conversely, only 6 percent (16) use the laparoscope in over 50 percent of resections. The percentage of surgeons who perform various procedures were right colectomy, 78 percent; left colectomy, 57 percent; stoma creations, 52 percent; anterior resection, 44 percent; Hartmann's closure, 42 percent; abdominoperineal resection, 27 percent; rectopexy, 18 percent; and total colectomy, 14 percent. If the preoperative diagnosis is known to be carcinoma, 196 (71 percent) surgeons attempted laparoscopic colorectal surgery, but 55 percent of surgeons (108) operated only for early lesions and 35 percent (68) only for palliation. To enable the procedure to be laparoscopically performed, 87 percent (243) of surgeons stated that they have changed their practice to include routine use of ureteral stents (23 percent), preoperative colonoscopic marking of small lesions (40 percent), or intraoperative colonoscopy. Despite increased use of endoscopy, there were 18 patients in whom the wrong segment of colon was removed. Moreover, nine patients had early local recurrence after resection of colon cancer, nine had early local recurrence after rectal cancer resection, and five had early port-site recurrence. Although 255 (40 percent) surgeons surveyed would themselves undergo laparoscopic colorectal surgery for a rectal villous adenoma, only 38 (6 percent) would have a laparoscopic anterior resection for cancer. CONCLUSIONS: Several important problems exist including early port-site recurrence and a dual surgical standard. Although many surgeons are eager to practice laparoscopic colorectal surgery on their patients with carcinoma, they are reluctant to have the new technique applied to themselves.

Colectomy↗
PubMed1995

Classes of tissue hypoxia.

We identify eight causes of tissue hypoxia, falling into three classes, A, B, and C, depending upon the effect on the critical mixed venous pO2 and the optimal oxygen consumption rate. The critical mixed venous pO2 is the value above which the oxygen consumption rate is optimal and independent of the mixed venous pO2 and below which the oxygen consumption rate decreases towards zero. Class A hypoxia: primary decrease in mixed venous pO2. Causes: 1) ischaemic hypoxia (decrease in cardiac output), 2) low-extractivity hypoxia (decrease in oxygen extraction tension, px). Class B hypoxia: primary increase in critical mixed venous pO2. Causes: 1) shunt hypoxia (increased a-v shunting), 2) dysperfusion hypoxia (increased diffusion length from erythrocytes to mitochondria and/or decreased total capillary endothelial diffusion area, e.g., tissue oedema, microembolism), 3) histotoxic hypoxia (inhibition of the cytochrome chain). Class C hypoxia: primary increase in optimal oxygen consumption rate. Causes: 1) uncoupling hypoxia (uncoupling of the ATP formation associated with O2 reduction), 2) hypermetabolic hypoxia (increased energy metabolism, e.g., due to hyperthermia).

Adenosine Triphosphate↗
PubMed1995

Functional results of the double-stapled ileoanal reservoir.

BACKGROUND: The preferred method for creation of an ileoanal reservoir is still controversial. We prospectively studied the functional and physiologic outcome of our patients who underwent a double-stapled ileoanal reservoir (DSIAR). STUDY DESIGN: All consecutive patients who underwent restorative proctocolectomy with a DSIAR between 1988 and 1993 were evaluated. Functional results were assessed by questionnaires and anal manometry preoperatively and two, 12, and 24 months postoperatively. RESULTS: One hundred forty patients (90 males and 50 females) with a mean age of 40.7 (range, 12 to 71) years were evaluated. Of these, 107 patients (77 percent) had ulcerative colitis, 21 (15 percent) had familial adenomatous polyposis, six (4 percent) had indeterminate colitis, and six (4 percent) had a post-operative diagnosis of Crohn's disease. One hundred twenty-four (95 percent) of the 131 patients with closed stomas were available for functional and manometric evaluation at a mean follow-up period of 24 months. A 32 percent decline in the mean resting pressure (from 71.3 +/- 4 to 48.2 +/- 3.4 mm Hg) occurred early after DSIAR (p < 0.001) with partial recovery by 24 months. The maximal internal sphincter resting pressure showed a 39 percent decline (from 90.8 +/- 4.9 to 55.3 +/- 5.7 mm Hg, p < 0.005) with recovery after 12 months. There were no significant changes in the length of the high-pressure zone or mean or maximal squeeze pressures. A mean of 5.4 (two to 13) bowel movements occurred during the day and a mean of 1.2 (zero to four) occurred at night. Perfect or almost perfect continence was reported during the day and night, respectively, by 95 and 92 percent of the patients. Overall perioperative complications occurred in 30 patients (21 percent) including septic complications in eight (6 percent), and pouchitis in eight (6 percent). There was one postoperative death (0.7 percent). CONCLUSIONS: Double-stapled ileoanal reservoir is associated with good subjective functional and objective physiologic results and has acceptable rates of morbidity and mortality.

Adenomatous Polyposis Coli↗
PubMed1994

The new class II transposon Tn163 is plasmid-borne in two unrelated Rhizobium leguminosarum biovar viciae strains.

Tn163 is a transposable element identified in Rhizobium leguminosarum bv. viciae by its high insertion rate into positive selection vectors. The 4.6 kb element was found in only one further R. leguminosarum bv. viciae strain out of 70 strains investigated. Both unrelated R. leguminosarum bv. viciae strains contained one copy of the transposable element, which was localized in plasmids native to these strains. DNA sequence analysis revealed three large open reading frames (ORFs) and 38 bp terminal inverted repeats. ORF1 encodes a putative protein of 990 amino acids displaying strong homologies to transposases of class II transposons. ORF2, transcribed in the opposite direction, codes for a protein of 213 amino acids which is highly homologous to DNA invertases and resolvases of class II transposons. Homology of ORF1 and ORF2 and the genetic structure of the element indicate that Tn163 can be classified as a class II transposon. It is the first example of a native transposon in the genus Rhizobium. ORF3, which was found not to be involved in the transposition process, encodes a putative protein (256 amino acids) of unknown function. During transposition Tn163 produced direct repeats of 5 bp, which is typical for transposons of the Tn3 family. However, one out of the ten insertion sites sequenced showed a 6 bp duplication of the target DNA; all duplicated sequences were A/T rich. Insertion of Tn163 into the sacB gene revealed two hot spots. Chromosomes of different R. leguminosarum bv. viciae strains were found to be highly refractory to the insertion of Tn163.

Amino Acid Sequence↗
PubMed1993

[Disordered peripapillary microcirculation in glaucoma patients].

To study the haemodynamics of the peripapillary choroid, perfusion pressure videoangiography (PVA) was performed in six healthy subjects and in seven patients with primary open-angle glaucoma (poag). In healthy subjects the peripapillary part of the choroid starts filling at distinctly lower ocular perfusion pressures than other parts of the choroid. The mean difference in perfusion pressure between peripapillary and perimacular filling was 13.6 mmHg in the six healthy subjects. A different filling pattern of the choroid was found in the seven glaucoma patients. The mean difference in perfusion pressure between the beginning of peripapillary and the beginning of perimacular perfusion of the choroid was found to be as small as 1.9 mmHg. That the filling of the peripapillary choroid observed by PVA in healthy subjects is found to start at lower perfusion pressures than in the other parts is explained by autoregulative dilatation of the peripapillary choroidal arterioles resulting from artificially raised intraocular pressure during the PVA examination. In the poag patients the peripapillary choroidal arterioles were dilated either insufficiently or not at all. The following conclusions are drawn: (1) The peripapillary choroid of healthy persons shows effective autoregulation securing the blood supply to the prelaminar part of the optic nerve. (2) In poag the peripapillary choroid has lost the capability of effective autoregulation.

Adult↗
PubMed1990

[In-vitro plaque accumulation on different filling materials].

The influence of the surface roughness of dental filling materials as well as of specific properties of materials on plaque accumulation was to be tested in a comparative study for various materials (Degulor S, Amalcap SAS, Visio Dispers, Ketak-Fil, CuproDur, Harvard Cement) was to be tested in a comparative investigation. For this purpose, the different materials were placed in a Streptococcus mutans NCTC 10449 culture medium containing sucrose, and incubated for three days at 37 degree C. Following this, the specific accumulation of polysaccharides formed outside of cells (plaque) was subjected to gravimetric analysis. Filling materials that take a high polish (Degulor S, Amalcap SAS, Visio Dispers) accumulated only 25 to 50% as much plaque as did cements. Within the group of cements there were also differences (up to 40%) in spite of similar surface roughness. These differences are presumably due to properties specific to the materials. In preliminary examinations of the products named, antibacterial effects were registered in three cases (Degulor S, Harvard Cement and Cupro-Dur--inhibiting areola between 1 and 7.5 mm).

Dental Amalgam↗
PubMed1989

Apparatus for the electrical characterisation of conductive fluids.

Non-invasive and fully automated conductimetric measurements of electrolyte and bacterial samples were achieved in a closed volume test cell, comprising a magnetic field coil and detector. By monitoring field induced currents in sample electrolytes the magnitude of the sample current was shown to vary as the inverse of the sample impedance. The impedance characteristic was shown to be that of an LCR resonant circuit. This characteristic is primarily a function of the applied frequency and the solution/cell properties being dependent on the solution conductivity and dielectric permittivity at any given concentration. Small changes in sample dielectric permittivity in the presence of a large background conductivity are shown to be significant. The apparatus described can provide fixed or swept frequency conductivity measurements in the range 1 kHz to 2.25 MHz with a lower conductivity sensitivity of 0.9 x 10(-3) Scm-1. Bulk impedimetric characteristics of cell suspensions are derived by a two stage measurement.

Bacillus megaterium↗