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A Metzger

Publications and source records attributed to A Metzger.

At least 19 recordsLinked to original sources
PubMed2002

Measurement of spin-transfer observables in p p-->Lambda Lambda at 1.637 GeV/c.

Spin-transfer observables for p p-->Lambda Lambda have been measured using a transversely polarized frozen-spin target and a beam momentum of 1.637 GeV/c. Current models of the reaction near threshold are in good agreement with existing measurements performed with unpolarized particles in the initial state but produce conflicting predictions for the spin-transfer observables Dnn and Knn (the normal-to-normal depolarization and polarization transfer), which are measurable only with polarized target or beam. Measurements of Dnn and Knn presented here are found to be in disagreement with predictions from these models.

Journal Article↗
PubMed2001

Telomere shortening and decreased replicative potential, contrasted by continued proliferation of telomerase-positive CD8+CD28(lo) T cells in patients with systemic lupus erythematosus.

To evaluate whether the immune system of systemic lupus erythematosus (SLE) patients shows features of premature aging, we compared telomere length and proliferative potential of SLE peripheral blood mononuclear cells (PBMC) (N = 90) to those of controls (N = 64). SLE samples showed accelerated loss of telomeric DNA (P = 0.00008) and higher levels of senescent (< or =5 kb) telomeric DNA (P = 0.00003). Viability cell counts and CFSE tracking in 6-week-old cell cultures indicated that SLE PBMC (CD8+ and CD4+ T cells) underwent fewer mitotic cycles and had shorter telomeres than controls (P = 0.04). However, a CD8(+)CD28(lo) T cell subset expanded preferentially in SLE-derived bulk cultures (P = 0.0009), preserved telomeric DNA (P = 0.01 vs entire CD8+), and displayed telomerase activity [2.1 telomerase arbitrary units (TAU) vs 0.5 TAU in CD8+CD28(hi) cells and 0.3 TAU in bulk PBMC; P = 0.05]. These T cell anomalies could be due to chronic in vivo stimulation of the immune system and may contribute to the immune dysregulation found in SLE.

Adult↗
PubMed2001

Optimization of Gamma knife treatment planning via guided evolutionary simulated annealing.

We present a method for generating optimized Gamma Knife (Elekta, Stockholm, Sweden) radiosurgery treatment plans. This semiautomatic method produces a highly conformal shot packing plan for the irradiation of an intracranial tumor. We simulate optimal treatment planning criteria with a probability function that is linked to every voxel in a volumetric (MR or CT) region of interest. This sigmoidal P+ parameter models the requirement of conformality (i.e., tumor ablation and normal tissue sparing). After determination of initial radiosurgery treatment parameters, a guided evolutionary simulated annealing (GESA) algorithm is used to find the optimal size, position, and weight for each shot. The three-dimensional GESA algorithm searches the shot parameter space more thoroughly than is possible during manual shot packing and provides one plan that is suitable to the treatment criteria of the attending neurosurgeon and radiation oncologist. The result is a more conformal plan, which also reduces redundancy, and saves treatment administration time.

Algorithms↗
PubMed2001

Anemia and interleukin-10, tumor necrosis factor alpha, and erythropoietin levels among children with acute, uncomplicated Plasmodium falciparum malaria.

Anemia is an important complication of malaria, and its pathogenesis is not well understood. To gain insight into potential age-related relationships between tumor necrosis factor alpha (TNF-alpha), interleukin 10 (IL-10), erythropoietin, and anemia during acute malaria, 273 children of ages 12 to 120 months presenting with acute, uncomplicated malaria in Kampala, Uganda, were monitored at enrollment and 3 and 7 days later. Younger children had higher geometric mean erythropoietin, TNF-alpha, and alpha(1)-acid glycoprotein (AGP) concentrations than older children. Univariate regression analysis revealed that age, log(10) erythropoietin levels, IL-10/TNF-alpha ratio, and AGP levels were each significantly associated with hemoglobin levels at baseline. Hemoglobin concentrations were inversely correlated with the log(10) erythropoietin level at all three visits. For the older age groups, higher levels of TNF-alpha were significantly associated with higher IL-10 levels at all three visits, but this relationship was significant only at baseline for younger children. These data suggest that younger children do not maintain IL-10 production in response to the inflammatory process, and this mechanism may contribute to the more severe anemia found in younger children. Acute malaria is an illness whose incidence and severity are largely age dependent. Further studies are needed to understand the relationships between age-related immune responses to malaria and their role in the pathogenesis of malarial anemia.

Acute Disease↗
PubMed2001

Antioxidant status and acute malaria in children in Kampala, Uganda.

Although antioxidant status has been implicated in the pathogenesis of malaria, these factors need further characterization. A longitudinal study was conducted involving 273 children 1-10 years of age with acute, uncomplicated malaria in Kampala, Uganda. Plasma vitamin A, carotenoids, and vitamin E were measured at enrollment and on day 7. Malaria parasitemia was measured at enrollment, on day 3, and on day 7. Malaria parasitemia had completely cleared in 57.1% and 85.3% of children by day 3 and day 7, respectively. Plasma vitamin A, alpha-carotene, beta-carotene, lycopene, lutein/zeaxanthin, and vitamin E were depressed at enrollment and increased by day 7. Multivariate analyses showed that higher plasma lycopene concentrations at enrollment were associated with clearance of parasitemia between enrollment and day 3 (odds ratio = 1.46, 95% confidence interval = 1.07-2.06, per 0.10 micromol/L of lycopene). This study suggests that children with acute malaria have depressed plasma concentrations of antioxidants, and that higher plasma lycopene is associated with more rapid clearance of malaria parasitemia.

Acute Disease↗
PubMed2000

Intraoperative magnetic resonance image guidance in neurosurgery.

Recently, there has been a burgeoning interest in the use of image-guided navigation to improve the safety and effectiveness of neurosurgical procedures. The intraoperative use of magnetic resonance imaging (MRI) provides the most accurate guidance available. This report discusses the hardware and software improvements that have made intraoperative MRI a reality and describes the use of this technology for neurosurgical intraoperative guidance.

Brain Neoplasms↗
PubMed2000

[Laparoscopic gastric banding].

The introduction of laparoscopic gastric banding appears to have revolutionized bariatric surgery. This review presents this new method in terms of indications, operative technique and preliminary results according to our own experience as well as reports in the literature. It seems that a long-term weight reduction of more than 50% excess weight can be achieved with a low morbidity rate. In the near future laparoscopic gastric banding can possibly become the procedure of choice for the treatment of morbid obesity.

Adult↗
PubMed1999

Exogenous IL-10 and IL-4 down-regulate IL-6 production by SLE-derived PBMC.

The elevated expression of IL-6 and IL-10 may have an important role in SLE pathogenesis. IL-6 production by normal monocytes can be inhibited by IL-10, and it has been suggested that SLE monocytes are refractory to this negative signal. To examine this possibility, the effects of regulatory factors on IL-6 expression by SLE PBMC (N = 51) were compared to effects on control PBMC (N = 21). We found that (1) exogenous rIL-10 and rIL-4 mediated reduction of constitutive and lectin-induced IL-6 in monocytes of SLE patients as effectively as that of controls; (2) IL-6 mRNA decay was significantly delayed in SLE with active disease (P < 0.001); (3) adding rIL-10 or neutralizing endogenous IL-1 beta and TNF-alpha down-regulated IL-6 mainly by destabilizing IL-6 transcripts, whereas exogenous IL-4 and TGF beta 1 down-regulated IL-6 transcriptionally; (4) time kinetics and levels of IL-10 were lower than those of IL-6 and IL-1 beta. Thus, contrary to a previous report, IL-6 production by SLE PBMC responds normally to regulatory signals, and the IL-6 overexpression in SLE may be due, at least in part, to the kinetics and availability of regulatory cytokines.

Adult↗
PubMed1998

Complications of laparoscopic cholecystectomy in Switzerland. A prospective 3-year study of 10,174 patients. Swiss Association of Laparoscopic and Thoracoscopic Surgery.

BACKGROUND: We set out to analyze the technical aspects, intraoperative complications, morbidity, and mortality of laparoscopic cholecystectomy in a multi-institutional study representative of Switzerland. METHODS: Data were collected from 10,174 patients from 82 surgical services. A total of 353 different parameters per patient were included. RESULTS: We found intraoperative complications in 34.4% of patients and had a conversion rate of 8.2%. This rate was significantly increased in patients with complicated cholelithiasis and in those with previous upper-but not lower-abdominal surgery. In most cases, conversions to open procedures were required because of technical difficulties due to inflammatory changes and/or unclear anatomical findings at the time of operation. Bleeding was a common intraoperative complication, that significantly increased the risk of conversion. Patients with loss of gallstones in the peritoneal cavity had increased rates of abscesses. The rate of common bile duct injuries was 0.31%, but it decreased significantly as the laparoscopic experience of the surgeon increased. The rate of common bile duct injuries was not increased in patients with acute cholecystitis or in the 1.32% of patients undergoing laparoscopic common bile duct exploration. Intraoperative cholangiography did not reduce the risk of common bile duct injuries, but it allowed them to be diagnosed intraoperatively in 75% of patients. Local complications were recorded in 4.79% of patients, and systemic complications were seen in 5.59%. The mortality rate was 0.2%. CONCLUSIONS: Although laparoscopic cholecystectomy is a safe procedure, the rate of conversion to open cholecystectomy is still substantial. The conversion rate depends both on the indication and intraoperative complications. There is still a 10.38% morbidity associated with the procedure; however, the incidence of common bile duct injuries, which decreases with growing laparoscopic experience, was relatively low.

Cholangiography↗
PubMed1997

SDZ HTF 919 stimulates canine colonic motility and transit in vivo.

Effects of the nonbenzamide 5-hydroxytryptamine4 agonist SDZ HTF 919 on gastrointestinal motility are unclear. Our aim was to assess the in vivo effects on gastrointestinal and colonic transit of radiolabeled residue and on colonic phasic contractility. In six female dogs, transit was measured over a period of 2 days by radioscintigraphy and colonic motility was measured by pneumohydraulic perfusion manometry of the proximal and distal colon. SDZ HTF 919 was administered initially by bolus i.v. infusion, followed by s.c. injection 8 and 16 hr later. Doses tested were 0.03, 0.1 and 0.3 mg/kg, and isotonic saline and vehicle served as controls in each dog. Stomach and small bowel transit was not significantly altered by SDZ HTF 919. Overall, i.v. SDZ HTF 919 accelerated colonic transit during the first 1 hr, compared with controls. These effects were significant even with the lowest dose of SDZ HTF 919. Responses to higher infusion doses were more variable. SDZ HTF 919 did not cause significant changes in quantitative pressure indices, such as amplitude or motor index, in the small bowel or colon. Prolonged postprandial colonic contractions, each lasting >30 sec, were noted after each i.v. agent and were significantly more frequent with the 0.03 mg/kg dose than with control (vehicle) treatment. Thus, SDZ HTF 919 accelerates canine colonic transit in vivo during the first 1 hr after i.v. administration. SDZ HTF 919 appears to be a promising agent for stimulation of mammalian colonic transit.

Animals↗
PubMed1996

Laparoscopic stapler appendectomy. A prospective study of 267 consecutive cases.

BACKGROUND: The value of laparoscopic appendectomy remains controversial. Therefore, we investigated the accuracy of diagnostic laparoscopy in detecting acute appendicitis and tested the applicability and safety of stapling appendectomy as a routine procedure. METHODS: Data from 267 consecutive patients with suspicion of acute appendicitis were recorded prospectively. RESULTS: Histopathological examination revealed nonperforated and perforated appendicitis in 63.3% and 13.1%, respectively, and no inflammation in 10.8%. Other pathological findings were observed in 12.7%. Diagnostic laparoscopy detected appendicitis with a sensitivity and specificity of 95.6% and 96.6%, respectively; the positive and negative predictive value were 99.5% and 74.3%, respectively. Morbidity was 10.2% in total and 40% for perforated appendicitis. Planned laparoscopic reexploration reduced morbidity by 23.4% in patients with perforated appendicitis and substantial peritonitis. Mortality was 0.4%. CONCLUSIONS: Laparoscopy improves diagnostic accuracy for acute appendicitis and laparoscopic stapling appendectomy is a safe and efficient procedure for all forms of appendicitis.

Acute Disease↗
PubMed1995

Injury to the diaphragm and its repair during laparoscopic cholecystectomy.

Laparoscopic cholecystectomy has now become the "gold standard" for the treatment of gallstone disease. Parallel with the conversion from the open to laparoscopic technique, some complications peculiar to the laparoscopic approach have been experienced. Such a technique-related complication, resulting in an injury to the diaphragm and its repair during laparoscopic cholecystectomy is presented.

Acute Disease↗
PubMed1995

[Laparoscopic cholecystectomy as standard therapy in acute cholecystitis. A prospective study].

Between November 1989 and May 1994 103 laparoscopic cholecystectomies were performed for acute cholecystitis. Conversion rate was 4.9%. Mortality was 0. Postoperative morbidity was 10.7% (6.8% local complications, 3.9% systemic complications). None of the complications lead to a reoperation, no injuries of the common bile duct occurred. These results compare favorably to randomized studies of open cholecystectomy and to published result of laparoscopic cholecystectomy for acute cholecystitis. Main determining factor for technical difficulty of the operation was the lapse of time between onset of symptoms and operation. This is expressed in statistically different mean operative times in patients with short (1-6 days) and long (7-14; 15-21 days) clinical history of acute cholecystitis. We therefore conclude that early surgery, in selected cases even emergency surgery is indicated and that in expert hands laparoscopic cholecystectomy can be the treatment of choice for acute cholecystitis.

Acute Disease↗
PubMed1995

Subcutaneous periumbilical metastasis of a gallbladder carcinoma after laparoscopic cholecystectomy.

The frequency of gallbladder carcinoma is 1.2 to 7.4% of all cholecystectomy specimens. In open cholecystectomy for gallstone disease, undetected gallbladder carcinoma is found postoperatively in the histological examination in 0.3%. Tumor cells of these clinically inapparent gallbladder carcinomas can be implanted at the trocar sites during laparoscopic cholecystectomies. We report a case with subcutaneous tumor seeding at the navel trocar insertion site in a 65-year-old woman.

Abdominal Muscles↗
PubMed1994

[Laparoscopic cholecystectomy in morbid obesity].

In the early days of laparoscopic cholecystectomy (LC) morbid obesity was considered a relative contraindication for this procedure. With increased experience the procedure has been used in obese patients too. To evaluate the influence of morbid obesity on feasibility and outcome of LC, we performed a prospective study in 136 patients in whom LC was attempted between January 1991 and January 1992. Conversion to open cholecystectomy was necessary in 26 cases (19%). The remaining patients were divided into two groups. Group 1 consisted of 92 normal or slightly obese individuals, whereas 18 morbidly obese patients were included in group 2. Intraoperative problems (42% vs 61%) and postoperative morbidity (2% vs 11%) were less frequent in group 1, although not statistically significant. There was no difference in operating time (median for both groups: 110 minutes) and length of hospital stay (4 days). The incidence of late complications (3% vs 6%) was similar. We conclude that LC in morbidly obese patients, as in open surgery, is technically more demanding than in normal individuals. The operative risk was elevated (p < 0.05) as evidenced by a tendency to higher intra- and postoperative complication rates. Cholecystolithiasis in morbidly obese patients is a good indication for LC in the hands of well trained laparoscopic surgeons who are ready to convert to open surgery if problems arise.

Adult↗
PubMed1994

[Acute cholecystitis: indication for emergency laparoscopic cholecystectomy?].

Between 1989 and 1992, 43 patients underwent laparoscopic cholecystectomy for acute cholecystitis. Conversion to open cholecystectomy was necessary in one case (2.3%). Morbidity was 14%, i.e. 7% local complications and 7% systemic complications. No lesions of the CBD occurred and no reoperations or reinterventions were required. Mortality was 0%. The main determining factor for the technical difficulty of laparoscopic cholecystectomy was the lapse of time between onset of symptoms and operation. We show the duration of laparoscopic cholecystectomy during the first 6 days of acute cholecystitis (mean 104 min) is statistically different in the following groups of patients (7-14 days p = 0.0049; 15-21 days p = 0.0037; Mann-Whitney-U-test). We therefore conclude that laparoscopic cholecystectomy is a safe method in acute cholecystitis and that the ideal time of operation is as soon as possible within the first 6 days after onset of illness. Performance of laparoscopic cholecystectomy should not be delayed during this period of acute cholecystitis. If the procedure is carried out by well trained laparoscopic surgeons the risks and complications are equal to those of open cholecystectomy.

Acute Disease↗