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Biomedical subjects

S Merkel

Publications and source records attributed to S Merkel.

At least 19 recordsLinked to original sources
PubMed2000

Raman spectroscopy of iron to 152 gigapascals: implications for Earth's inner core

Raman spectra of hexagonal close-packed iron (varepsilon-Fe) have been measured from 15 to 152 gigapascals by using diamond-anvil cells with ultrapure synthetic diamond anvils. The results give a Gruneisen parameter gamma(0) = 1.68 (+/-0.20) and q = 0.7 (+/-0.5). Phenomenological modeling shows that the Raman-active mode can be approximately correlated with an acoustic phonon and thus provides direct information about the high-pressure elastic properties of iron, which have been controversial. In particular, the C(44) elastic modulus is found to be lower than previous determinations. This leads to changes of about 35% at core pressures for shear wave anisotropies.

Journal Article↗
PubMed2000

[Hereditary colonic carcinoma without polyposis (HNPCC) without satisfying the Amsterdam criteria].

Epidemiologic data suggest that an underlying genetic disposition can be detected in up to 10% of all colorectal cancer patients and autosomal dominantly inherited hereditary non-polyposis colorectal cancer (HNPCC) is the entity most frequently identified. It was described first by A. Warthin in 1895 in "Family G" and is characterized by a predisposition to an early onset of colorectal cancer and other intestinal or genitourinary tumors. We report the case of a 61-year-old woman with five different cancers. Although the strict Amsterdam Criteria were not fulfilled, molecular analysis revealed HNPCC; further genetic testing in the family confirmed that the 36-year-old and so far healthy son had inherited the germline mutation of his affected mother. Genetic testing in clinically suspected HNPCC cases is recommended for patients with colorectal cancer meeting the Amsterdam Criteria. In patients meeting one of Bethesda Criteria 2-7 without meeting the Amsterdam Criteria, germline mutation analysis is recommended only in MSI-positive tumors.

Adult↗
PubMed2000

D3 lymph node dissection in gastric cancer: evaluation of postoperative mortality and complications.

Since November 1995 we have been performing a D3 lymph node dissection in patients undergoing an operation for gastric cancer with a curative intent. The aim of the present study was to evaluate whether this procedure results in an increased postoperative mortality or complication rate in a Western population. Between November 1995 and August 1997 the postoperative courses of 76 patients were retrospectively assessed (45.3 lymph nodes per patient, lymph node ratio: 0.16). The patient outcome was compared with data from a historic control group of patients (n = 383) in whom the newly established D2 dissection was studied in our department. Regarding the demographic, clinical, and tumor-pathologic data, and the choice of resection and reconstructive procedures, the two groups differed only slightly. The postoperative mortality of 1% was lower (vs 6.8%) while the overall complication rate of 34% (vs 32.1%) was identical. In particular, no anastomotic leakage (vs 9.4%) and fewer nonsurgical complications (17.1% vs 27.9%) occurred. The reoperation rate was 1% vs 9.7%. However, in 6% of the patients drainage tubes had to be inserted under computed tomographic guidance. The average hospital stay remained unchanged (21.9 vs 20.7 days). A D3 dissection was shown to be feasible while demonstrating no disadvantages in the patients when compared with the D2 procedure.

Adenocarcinoma↗
PubMed1998

Combined operative and endovascular treatment of a post-traumatic embolizing aneurysm of the subclavian artery.

PURPOSE: To describe a combined endovascular and surgical approach for an embolizing subclavian artery aneurysm as an alternative to conventional reconstructive surgery. METHODS AND RESULTS: A 39-year-old woman presented with a post-traumatic aneurysm of the left subclavian artery and occlusion of the brachial artery due to embolization. Exclusion of the aneurysm was achieved by intraoperative implantation of a covered stent during simultaneous reconstruction of the brachial artery by a venous bypass graft. The patient is well and free of symptoms 24 months after the operation. CONCLUSIONS: Repeat operative trauma to the supraclavicular region was avoided by transluminal implantation of a covered stent-graft in combination with an axilloulnar bypass procedure for chronic embolic occlusion of the brachial artery.

Adult↗
PubMed1998

[Malignant melanoma of the skin: is there a curative surgical approach in locoregional metastasis?].

Between 1969 and 1993 at the Surgical University Hospital of Erlangen, 273 patients with synchronous or metachronous locoregional metastases were operated on with curative intent; patients with distant metastases at the time of primary operation or first recurrency were excluded. In 216 patients (79.1%) a curative operation was performed and we achieved a statistically significant improvement of the 5-year-survival rate compared with those patients treated only palliatively (39.3% vs. 21.1%, p < 0.01). If regional lymph node metastases occur, the prognosis becomes significantly worse (5-year survival rate 45.2% vs. 25.2%, p < 0.01); hyperthermic isolated limb perfusion shows a high importance in the treatment of locoregional metastases and the 5-year survival rate of patients treated with hyperthermic limb perfusion is significantly higher (39.0 vs. 64.2%, p < 0.05).

Adolescent↗
PubMed1996

Lumbar epidural morphine infusions for children undergoing cardiac surgery.

OBJECTIVE: To determine whether outcomes and costs in children undergoing cardiac surgery are affected by the method of postoperative pain management. DESIGN: Retrospective, case control. SETTING: Tertiary care children's hospital in a university setting. PARTICIPANTS: Two groups of children undergoing cardiac surgery for palliation or repair of congenital heart disease oer a 21-month period between January 1993 and September 1994. INTERVENTIONS: Lumbar epidural morphine infusions (LEM) in one group, and IV opioid (IVO) medication in the other for postoperative pain control. MEASUREMENTS AND MAIN RESULTS: Hospital courses of 27 LEM patients and 27 IVO patients were analyzed. In LEM patients, epidural catheters were placed following anesthetic induction, but before anticoagulation. A bolus of 50 micrograms/kg of preservative-free morphine sulfate was administered through the catheter, followed by a continuous infusion at 3 to 4 micrograms/kg/h for 22 to 102 (median, 46) hours postoperatively. The IVO patients received 50 micrograms/kg, IV, of fentanyl before incision followed by a continuous infusion at 0.3 microgram/kg/min. The fentanyl infusion rate was decreased to 0.1 microgram/kg/min postoperatively and maintained for 24 hours. Although the LEM group was demographically similar to the IVO group, times to tracheal extubation, transfer from the intensive care unit, and resumption of regular diet were significantly shorter in LEM patients. LEM and IVO patients received similar amounts of fentanyl during surgery (10.4 +/- 19.3 micrograms/kg/h v 13.7 +/- 8.1 micrograms/kg/h, p = 0.4). However, during postoperative recovery, LEM patients who were extubated late received significantly less supplemental opioid medication than IVO patients extubated late during the first 5 postoperative days. No complications related to dural puncture, bleeding into the epidural space, or respiratory depression were encountered. Pruritus and nausea/vomiting were the most commonly reported morbidities in both groups. Fifty-six percent (15/27) of LEM patients and 41% of IVO patients reported pruritus (p = 0.4). There was no significant difference in the incidence of nausea and vomiting between the groups (34% v 30%, respectively). CONCLUSIONS: Given the present methodologic limitations, the authors found improved outcomes only in LEM patients extubated late compared with IVO patients. Randomized, prospective studies to evaluate this conclusion and to determine the comparative efficacy and safety of LEM infusions are in progress.

Adolescent↗
PubMed1995

[Toxoplasmosis and pregnancy--findings from umbilical cord blood screening in 30,000 newborn infants].

Cord blood screening for congenital toxoplasmosis was performed prospectively on 30,000 samples collected between 1986 and 1994 in the region of Basel, Switzerland, covering up to 95% of all births. Congenital infection was suspected in cases of serum with specific antitoxoplasma IgM or IgA or with a level of specific IgG above 300 IU/ml as measured by EIA from Sanofi-Pasteur. The percentage of cases to be screened declined from 2.5 to 1.2% and the cases of confirmed congenital toxoplasmosis from 0.073 to 0.033% during the observation period. This observation may be due to several reasons, such as improved primary prevention or more frequent diagnosis and treatment during pregnancy. In 178 cases of cord blood serology suspicious for acute toxoplasmosis, an enquiry with the gynecologist in charge of the pregnant woman was carried out. 126 mothers (71%) presented with a confirmed immunity against Toxoplasma gondii early in pregnancy and screening of the child was not needed. From 37 pregnancies (21%) no information was available. 15 out of 24 confirmed cases of toxoplasmosis of the mother during pregnancy were detected by cord blood analysis. In 17 of 24 cases of maternal toxoplasmosis treatment with spiramycin, pyrimethamine/sulfadoxine or both was performed. 10 of 17 newborns from mothers treated during pregnancy had elevated toxoplasma IgG titres at birth, but only one child was infected. 7 newborns had an inconspicuous toxoplasma serology at birth and were not infected. 7 cases of toxoplasmosis during pregnancy were detected by the check back and remained untreated; 4 out of 7 newborns had congenital toxoplasmosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Protozoan↗
PubMed1995

Synthesis and separation of protected tripeptide epimers by RP-HPLC.

Twenty three epimeric pairs of protected tripeptides of the type Z-Ala-Xaa-Val-OMe have been synthesized by conventional coupling procedures in solution. Optimal conditions for baseline separation of LLL/LDL epimers were found by high-performance liquid chromatography on a RP-18 column with aqueous methanol as mobile phase. The hydrophobic parameters (log kw) were determined for all tripeptides.

Amino Acid Sequence↗
PubMed1991

[Studies about the therapy of tuberculosis in East Germany (former GDR)].

On the basis of a questionnaire the therapy of 2285 patients with tuberculosis was evaluated for the years 1987-1989. The data of the GDR National Tuberculosis Register (9827 patients) were used for statistical comparison. 85% of the patients had a pulmonary tuberculosis, 947 patients (41% of all) excreted tubercle bacilli in the sputum. The average duration of treatment was 31.8 weeks, 94.7% of the patients were hospitalised for treatment for an average time of 12.4 weeks, the following outpatient treatment was 19.4 weeks in average. The initial phase (daily-treatment) in all cases of tuberculosis was 8.6 weeks, the follow-up phase was 23.2 weeks (all data are averages). The intermittent outpatient drug administration was made in 95% of cases under nurse control in outpatient departments. The initial treatment was started in 92.1% with 3 or 4 drugs (H/R/Z/S or E). Isoniacid and rifampicin were prescribed in 89.7% and pyrazinamide was used as a 4th drug. In the follow-up phase the combination isoniacid and rifampicin was employed intermittent in 75.7%. The delaytime for the evaluated cases was 38.8 days in average. The result of study shows, in most cases the patients were treated according to the recommendation of therapy. The clinical stay of patients is too long.

Adolescent↗
PubMed1990

[BCG osteomyelitis and arthritis].

Since 1980 an increase of the frequency of osteomyelitis after BCG vaccination has been described by some european countries. In the GDR osseous impairments as BCG complication are rarely. The authors report on an 18 months old boy with lesions of the distal tibia and the ankle-joint. He was vaccinated with BCG in the neonatal period. In contrast to the local findings general symptoms were unimportant. The surgical treatment was completed by antituberculotic chemotherapy. This treatment was successful.

Ankle Joint↗
PubMed1989

[Tuberculin sensitivity and tolerance of "direct" BCG vaccination of youths leaving school].

In 3,296 school-leavers (girls and boys aged 16 years with preceding BCG-vaccination as newborns and without boosting by tuberculin-testing or revaccination during the meantime) simultaneously with compulsory BCG-revaccination tuberculin testing with 2 TU PPD Dessau + Tween 80 was performed in 3 regions of the GDR (Cottbus, Erfurt, Neubrandenburg) in the 2nd half of 1985 and in the 1st quarter of 1986. Sensitivity to tuberculin was found in 7.3% considering reactions with greater than or equal to 6 mm induration as positive, and in 2.9% considering reactions with greater than or equal to 10 mm only. Positive reactions greater than or equal to 6 mm include remaining allergy caused by BCG and non-specific tuberculin sensitivity while a reaction limit greater than or equal to 10 mm is suitable to define tuberculosis infection prevalence. In contrast to studies performed 1973 and 1979 in the same territories a significant decrease in tuberculin sensitivity was evident (43.8% positive reactions (greater than or equal to 6 mm) in 1973 and 11.7% in 1979). The acceptability of "direct" BCG-revaccination has been estimated by evaluation of local reactions 4 weeks after vaccination in 2,123 school-leavers. The ulceration rate in tuberculin positive adolescents was significantly higher than in tuberculin negative. It showed highly significant decrease in comparison with 1979.

Adolescent↗
PubMed1989

[Recommendations for the therapy of atypical immunization courses and complications of BCG vaccination (Position: April, 1988)].

After introduction of the "direct" BCG-vaccination of the 16 years old youngsters in 1981 a small increase of atypical reactions and complications of the vaccination was probable. References and experiences about different therapy methods of these atypical reactions and complications gave rise to recommend uniform guide-lines for definition, diagnostic and therapy.

Adolescent↗
PubMed1988

[Specific and nonspecific tuberculin sensitivity in school children in East Germany. East German draft report of a multinational epidemiologic study of the prevalence of specific and nonspecific tuberculin sensitivity in Europe].

By means of dual-testing with tuberculin (2 TU PPD RT 23 and 2 TE PPD Dessau) and sensitin Scrophulaceum (5 TU PPD scroph.) evidence and degree of specific and non-specific tuberculin sensitivity in schoolchildren aged 7-14 years was examined under the conditions of preceding BCG-vaccination as newborns in the counties of Cottbus, Erfurt and Neubrandenburg. In a cohort of 2,792 children sensitivity to tuberculin was found in 5.98% considering positive reactions with greater than or equal to 6 mm induration and in 1.50% considering reactions with greater than or equal to 10 mm only. Reactions with induration of 6 mm and more comprehend remaining allergy caused by BCG while the limit greater than or equal to 10 mm seems to be suitable to define tuberculosis infection prevalence. Tuberculin sensitivity shows frequencies corresponding with the epidemiology of tuberculosis. Sensitivity to PPD scroph. increases from north to south with significant difference between the counties of Neubrandenburg and Erfurt. Nonspecific tuberculin sensitivity is partly prevalent in the counties of Cottbus and Erfurt.

Child↗
PubMed1986

[Daily ultrashort chemotherapy and intermittent short-term chemotherapy with 4 drugs of communicable pulmonary tuberculosis treated for the first time. Results of a cooperative multicenter study].

Three short-course regimens, all comprising isoniazide (H), rifampicine (R), streptomycine (S) and pyrazinamide (Z), are compared in a randomized prospective cooperative clinical trial. The drugs are given daily in a 3-month regimen (3-HRSZ), twice a week in a 6-month regimen (6-HRSZ2), and in a further two-phase 6-month regimen the 4 drugs are administered 3 times a week for the first 3 months followed by the administration of HSZ twice a week (without R) for further 3 months (3-HRSZ3/3-HSZ2). The number of patients admitted to study is 80, 144 and 139 respectively. The 3-month regimen has been stopped because of a high rate of relapses. 17 p.c. of the patients admitted have to be excluded from analysis for various reasons, out of these 5.8 p.c. because of adverse reactions. Two thirds of the patients had heavily positive sputum cultures at the start. 300 patients completed therapy. At the end of therapy cultures were negative in 94 p.c., 100 p.c. and 99 p.c. respectively. The rate of bacteriological relapses is 19 p.c. in 3-HRSZ, 9 p.c. in 3-HRSZ3/3-HSZ2 and 3 p.c. in 6-HRSZ2, during a follow-up period of 3-4 years after completing therapy. The acceptability was good in all treatment groups. Adverse reactions like "flu" were rarely observed. Increased blood urea was common but in general without clinical symptoms. Elevation of ALAT and ASAT was relatively frequent but mostly transient and without clinical importance. The results served as basis for the new "Recommendation for Treatment of Tuberculosis" and are interpreted with regard to practical consequences and possibilities for further rationalisation of treatment.

Adolescent↗