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Biomedical subjects

W Marx

Publications and source records attributed to W Marx.

At least 19 recordsLinked to original sources
PubMed2004

Simultaneous bilateral laparoscopic adrenalectomy: a surgical option for multiple endocrine neoplasia (MEN 2) patients with bilateral pheochromocytomas.

Multiple endocrine neoplasia (MEN 2) is a rare disorder. Of this group, 42% develop a pheochromocytoma of which 60% will have bilateral involvement. Although the benefits of unilateral laparoscopic adrenalectomy have been well documented, fewer cases of simultaneous bilateral laparoscopic adrenalectomy have been reported. We present the cases of three patients with MEN 2 who underwent successful simultaneous bilateral laparoscopic adrenalectomy after their initial presentation with bilateral pheochromocytoma. Although the management of bilateral pheochromocytomas has traditionally been approached via open laparotomy or bilateral posterior incisions, the bilateral laparoscopic approach should be considered a viable alternative for patients requiring surgical intervention. Clinical outcomes and complications are similar to open laparotomy. Simultaneous bilateral laparoscopic adrenalectomy is a safe and effective procedure that results in a more rapid recovery and a shorter hospital stay for patients with bilateral pheochromocytomas originating from MEN 2.

Adrenal Gland Neoplasms↗
PubMed2002

Gastric bypass model in the obese rat to study metabolic mechanisms of weight loss.

A rat model replicating gastric bypass with Roux-en-Y (GB) as used in morbidly obese patients, evolved in our laboratory in stages, using the Zucker rat as an obese model (GB) is presented. In the final model, a 20% gastric fundic pouch to limit the gastric reservoir was created using two staple lines (Ethicon). A 4- to 5-mm end-to-side gastrojejunostomy and a 6- to 8-mm jejunojejunostomy, at 10 cm length of the Roux-en-Y limb, placed 16 cm below the ligament of Treitz, was hand sewn to create a limited area of nutrient digestion and absorption. Controls underwent sham operation. Rats were divided into: (i) sham-op ad lib-fed (Control); (ii) GB; and (iii) sham-op pair fed (PF) in two experiments. In Experiment 1, 24 Zuckers (control n = 8; GB n = 8; PF n = 8) were studied to assess the effectiveness of the model for weight loss. In Experiment 2, 24 Zuckers (8/group) were studied to confirm the effects of the operation on weight loss and on metabolic parameters. Boost was given for 4 days starting 24 h postop and then ground chow was given. Daily food intake (FI), meal size (MZ), meal number (MN), and body weight (BW) were measured. Rats were sacrificed on Day 20 in Experiment 1 and on Day 10 in Experiment 2. Serum metabolites and body fat weight were measured. Data were evaluated using Student's t test. Controls steadily gained BW (5.2-6.1 g/day), reaching approximately 500 g. In GB: FI, MZ, MN, BW, glucose, free fatty acids, insulin, and body fat decreased (P < 0.05). In PF: BW, insulin, triglycerides, and body fat decreased. A dependable, reproducible gastric bypass with Roux-en-Y obesity model was developed. This permits the study of biochemical and eventually molecular mechanism(s) of weight loss resulting from the operation.

Adipose Tissue↗
PubMed2001

[Immunology-related chronic progressive cicatricial conjunctival diseases: diagnosis, therapy and prognosis].

PURPOSE: We reviewed the records of patients with chronic cicatricial disease of the conjunctiva for differences in prognosis between clinical and histopathological subgroups of the disease and in therapeutic options. PATIENTS: In 30 patients (58 eyes) with an average age of 69 years (52-86) chronic cicatricial disease of the conjunctiva was diagnosed clinically. Only in 22/30 patients conjunctival biopsies could be performed. The correlation of histopathological and immunohistochemical diagnoses with clinical course under systemic immunosuppression was studied. RESULTS: 15/22 biopsies led to a classification into different subgroups. Under systemic immunosuppression disease ceased to progress for a mean time of 15 months in 13 of 15 patients with positive biopsies and in 9 of 15 without classification. The results after cyclosporine A therapy (4 of 5 patients stabilized after a mean of 27.5 months) and mycophenolate mofetil (8 of 11 patients stabilized at a mean of 7.8 months) were better than those after therapy with dapsone, azathioprine and cyclophosphamide. CONCLUSIONS: Histopathological and immunohistochemical examinations led to a classification in two-thirds of the patients with clinical aspects of chronic cicatricial disease of the conjunctiva. There was no correlation between different histopathological subgroups, success of therapy and prognosis of the disease. There is little hope in using new systemic immunosuppression such as cyclosporine A and mycophenolate mofetil.

Aged↗
PubMed2001

Improved objectivity of grading of T(A,1) transitional cell carcinomas of the urinary bladder by quantitative nuclear and proliferation related features.

AIM: To analyse whether the mean nuclear area of the 10 largest nuclei (MNA-10), the mitotic activity index (MAI), and Ki-67 immunoquantitative features have additional value to discriminate different grades of T(A,1) transitional cell carcinoma (TCC) of the urinary bladder. MATERIALS/METHODS: One hundred and fifty of 200 consecutive cases (75%) showing interobserver agreement on duplicate blind grade assessment by independent pathologists were studied. Using random numbers, the 150 cases were divided into sets for learning (n = 75) and testing (n = 75). Single and multivariate analyses were applied to discriminate the different grades in the learning set. The multivariate classifier developed in this way was evaluated in the test set (n = 75). RESULTS: With the MNA-10 alone, using the classification MNA-10 < 80 microm(2) = grade 1, 80 microm(2) < MNA-10 < 130 microm(2) = grade 2, MNA-10 > 130 microm(2) = grade 3, 71% of all 150 cases were correctly classified (69% of grade 1 v grade 2 and 76% of grade 2 v grade 3). With multivariate analysis, the best discriminating features in the learning set (17 grade 1, 30 grade 2, and 28 grade 3) between grades 1 and 2 were MNA-10 and MAI, and between grades 2 and 3 MAI and Ki-67. With these features, 94% of grade 1 v grade 2 and 97% of grade 2 v grade 3 were correctly classified in the learning set (overall, 95% correct, none of the grade 3 cases misclassified). In the test set the classification results were similar. When the three grades were entered at the same time for discrimination, Ki-67 area % and MAI was the best discriminating combination, both in the sets for learning and testing. Overall correct classification results in the sets for learning and testing were slightly lower, but still 94% and 92%. Most importantly, none of the grade 3 cases was misclassified; the classification shifts all occurred between grades 1 and 2. CONCLUSIONS: The combination of MNA-10, MAI, and Ki-67 gives much better discrimination between grades 1, 2, and 3 in T(A,1) TCC of the urinary bladder than MNA-10 alone. The similarity of the classification results of the learning set and test set are encouraging and this quantitative pathological grading model should be applied in a prospective study.

Aged↗
PubMed2000

[Impression and applanation tonometry in irregular corneas. Comparison with intraocular needle tonometry].

PURPOSE: During the past 4 years we have demonstrated in eyes with corneal pathology that applanation tonometry (Goldmann, Perkins) generally delivers falsely low measurements in comparison to intraocular needle tonometry. The aim of this study was to evaluate whether impression tonometry (Schioetz) is more precise than applanation tonometry in determining the intraocular pressure in eyes with corneal disorders. PATIENTS AND METHODS: In 75 eyes with suspected glaucoma and various corneal disorders, we performed applanation tonometry and impression tonometry before intraocular needle tonometry. Applanation tonometry was repeated after impression tonometry to unveil a possible tonography effect. Intraocular needle tonometry was performed thereafter. RESULTS: Applanation tonometry results were 4.1 +/- 5.3 mmHg below intraocular pressure as determined by intraocular needle tonometry. Impression tonometry results were also lower: 4.3 +/- 6.8 mmHg (5.5 g), 4.3 +/- 6.4 mmHg (7.5 g), and 4.8 +/- 7.0 mmHg (10.0 g). The differences between applanation tonometry and impression tonometry were statistically not significant. In contrast, all the differences between extraocular tonometry procedures and intraocular needle tonometry were statistically highly significant (P < 0.001). CONCLUSION: In corneal pathology both, applanation tonometry and impression tonometry do not deliver reliable results on an average. Only intraocular needle-tonometry delivers reliable results in these eyes.

Corneal Diseases↗
PubMed1999

A novel diagnosis of left paraduodenal hernia through laparoscopy.

A congenital intraperitoneal hernia, also known as a "paraduodenal hernia," is an extremely rare cause of intestinal obstruction. These hernias, which are caused by variations in intestinal rotation, present with symptoms ranging from intermittent abdominal pain to acute obstruction. Preoperative diagnosis is rare, and conventional treatment is usually by laparotomy. Laparoscopic diagnosis and repair has recently been reported in Japan. We present as case of a left paraduodenal hernia diagnosed and treated laparoscopically and a review of the literature.

Abdominal Pain↗
PubMed1999

[More than 4 years' experience with electronic intraocular needle tonometry].

BACKGROUND: Applanation tonometry in eyes with pathological corneae can often not be performed or delivers rather questionable results. We report on our 4-year experience with electronic intraocular needle tonometry. PATIENTS AND METHODS: After since 1994 developing and calibrating a system for intraocular needle tonometry, we have performed 395 measurements in 252 eyes with irregular corneae and suspicion of glaucoma. If applanation tonometry values could be obtained, they were compared with the true intraocular pressure. RESULTS: Depending on the kind of corneal pathology, applanation tonometry values were lower and sometimes much lower than true intraocular pressure. No serious complications occurred as a result of intraocular needle tonometry. CONCLUSIONS: Intraocular needle tonometry is a safe procedure and is the only way to measure intraocular pressure precisely in eyes with pathological corneae.

Adolescent↗
PubMed1999

The normal breast epithelium of women with breast cancer displays an aberrant response to estradiol.

Breast epithelial response to estradiol may play an important role in breast cancer etiology. We have examined the relationship between serum estradiol and progesterone levels and normal breast epithelial expression of estrogen receptor (ER) alpha, progesterone receptor (PgR), and epithelial proliferation (as reflected by the Ki-67 labeling index) in 121 women (50 newly diagnosed breast cancer cases and 71 benign breast disease controls). Simultaneous samples of grossly normal breast tissue and venous blood were obtained from women undergoing breast surgery. Serum estradiol and progesterone levels were measured by radioimmunoassay; breast epithelial ER, PgR, and Ki-67 expression was measured by immunohistochemistry. Linear regression, controlled for patient age and ductal and lobular composition of the tissue, showed that the breast epithelium of control women displayed an inverse correlation between serum estradiol and ER-alpha, which was not seen in case women (P for the difference in regression slopes = 0.001). PgR expression displayed a significant positive correlation with serum estradiol in cases, but not in controls. Epithelial proliferation had no relationship to either estradiol or progesterone in both cases and controls but showed an inverse relationship with ER in controls and a direct relationship in cases (P for the difference in regression slopes = 0.066). These results suggest a dysregulation of hormonal response in the normal breast epithelium of high-risk women, with lack of regulation of ER by estradiol, increased estrogen responsiveness as reflected by PgR expression, and a dissociation of ER expression and proliferative response.

Adult↗
PubMed1997

Role of nitric oxide and tumor necrosis factor on lung injury caused by ischemia/reperfusion of the lower extremities.

PURPOSE: Acute aortic occlusion with subsequent ischemia/reperfusion (I/R) of the lower extremities is known to predispose to lung injury. The pathophysiologic mechanisms of this injury are not clear. In the present study, we studied the role of tumor necrosis factor (TNF) and nitric oxide (NO) in lung injury caused by lower extremity I/R. METHODS: A rat model in which the infrarenal aorta was cross-clamped for 3 hours followed by 1 hour of reperfusion was used. The rats were randomized into five groups: group 1, aorta exposed but not clamped; group 2, aorta clamped for 3 hours, followed by 1 hour of reperfusion; group 3, 1 mg/kg dexamethasone administered before the aorta was clamped; group 4, 25 mg aminoguanidine, a specific inducible NO synthase (iNOS) inhibitor, administered before the aorta was clamped; and group 5, 2 mg/kg TNFbp, a PEG-ylated dimeric form of the high-affinity p55 TNF receptor I (RI), administered before the aorta was clamped. NO concentration in the exhaled gas (ENO) was measured, as an index of NO production by the lung, in 30 minute intervals during I/R. Serial arterial blood samples for TNF assay were obtained during the course of the experiment. At the end of the experiment, the lungs were removed and histologically examined for evidence of injury. RESULTS: ENO in group 2 increased from 0.7 +/- 0.3 ppb at baseline to 54.3 +/- 7.5 ppb at the end of ischemia and remained stable during reperfusion (54.6 +/- 8.5 ppb at the end of reperfusion). ENO production was blocked by aminoguanidine, by dexamethasone, and by TNFbp given before aortic occlusion. Serum TNF in groups 2, 3 and 4 increased rapidly during early ischemia, reaching its peak value 60 minutes after occlusion of the aorta, then gradually declined to baseline levels at the end of ischemia, and remained low during reperfusion. TNFbp decreased serum TNF concentration significantly when it was given before aortic occlusion. Histologic examination of the lungs at the end of the experiment revealed that aminoguanidine, dexamethasone, and TNFbp had a protective effect on the lungs. CONCLUSIONS: Serum TNF increases rapidly during lower extremity ischemia and causes increased production of NO from the lung by upregulating iNOS. Increased NO is associated with more severe lung injury, and iNOS blockade has beneficial effects on the lung. TNF blockade before ischemia decreases NO production by the lung and attenuates lung injury. ENO can be used as an early marker of lung injury caused by lower extremity I/R.

Animals↗
PubMed1997

[Semantic dimensions of vocabulary for emotional concepts].

The present paper analyzes the semantic features of positive and negative emotion names. In a pretest the 12 most typical positive rated emotion names were selected by means of a free listing of 70 Ss. These 12 items were presented to 42 Ss as stimulus words for a free association test. From this association data overlap coefficients were computed and analyzed by means of nonmetric multidimensional scaling. It was possible to fit the features "Soziale Nähe-Soziale Distanz" (social distance) und "Körperhaftigkeit" (Quality of body feeling) in the two-dimensional euclidian solution. In the same way as described above, an experiment was carried out with 11 negative emotion names. In this case it was possible to fit in the same two features and the feature "Aktivation" (activation).

Adult↗
PubMed1992

Isoflurane and nitrous oxide: comparative impact on cerebrospinal fluid pressure in patients with brain tumors.

The relative effects on cerebrospinal fluid pressure (CSFP) of equipotent concentrations of isoflurane and N2O were compared in 20 patients with brain tumors who had lumbar subarachnoid catheters in place. Patients were randomly assigned to receive one of two anesthetic sequences: group 1, 0.7% end-tidal isoflurane in O2, which was changed to 70% N2O in O2; or group 2, 70% N2O in O2, which was changed to 0.7% end-tidal isoflurane in O2. End-tidal PCO2 and percent end-tidal N2O and isoflurane were monitored by mass spectrometry from just before changing anesthetics (time = 0 min) until the end of a 20-min observation period (time = 20 min). Ventilation was held constant at PaCO2 = 36 +/- 1 mm Hg (mean +/- SE). The patients in group 1 sustained an increase in CSFP that reached a maximum of 33% above the value at 0 min, despite a 3-mm Hg decrease in PaCO2 (P < 0.05). By contrast, CSFP remained unchanged in group 2. Although the absolute increase in CSFP after replacement of isoflurane/O2 by N2O/O2 anesthesia was relatively small (9 +/- 1 to 12 +/- 2 mm Hg; P < 0.05), the absence of a similar effect in patients where N2O was replaced by isoflurane suggests that replacement of isoflurane by an equipotent concentration of N2O is more likely to lead to an increase in CSFP in patients with altered intracranial dynamics than is replacement of N2O by isoflurane.

Brain Neoplasms↗
PubMed1990

Magnetic motor-evoked potentials in epilepsy: effects of the disease and of anticonvulsant medication.

Magnetic motor-evoked potentials were recorded in 53 patients with medically intractable, mainly temporal lobe epilepsy and compared with potentials of 110 healthy volunteers. The motor-evoked potentials were reevaluated in 16 of the 53 patients after substantial reduction of antiepileptic drug doses. The objective was to assess the effect of epilepsy and of anticonvulsant medication on the central motor system. In subjects receiving antiepileptic treatment, cortical threshold intensities were markedly elevated and peripheral latencies were prolonged. Cortical threshold intensities and peripheral latencies decreased to approach control values after anticonvulsant medication was reduced but were increased in patients treated with 2 or 3 anticonvulsant agents instead of 1. Additionally, high levels of interictal epileptiform activity and a high frequency of seizures significantly decreased the central motor conduction time and, in part, threshold intensities. The central motor conduction time was further diminished after reduction of anticonvulsant treatment and increased when several drugs were administered. The duration of epilepsy, the location of the epileptic focus, and the type of the epileptic seizure did not affect motor-evoked potentials. Conclusively, central motor pathways are endogenously facilitated by epileptiform activity even if clinical signs of their involvement are absent. Anticonvulsant medication exerts major reversible effects on magnetic motor-evoked potentials.

Adolescent↗
PubMed1990

Cerebrovasculr response to CO2 in edematous brain during either fentanyl or isoflurane anesthesia.

Cerebral blood flow response to changes in PaCO2 was studied in the edematous cerebral cortex of 19 patients with malignant supratentorial tumors using laser Doppler flowmetry technology. General anesthesia for craniotomy was induced with thiopental, 3-5 mg/kg i.v., and N2O, 60% in O2. In random sequence, 8 patients were assigned to receive fentanyl, 6 +/- 1.6 (SEM). mug/kg i.v.; the other 11 received isoflurane, 0.56% end-tidal + 0.07 (SEM). After a craniotomy bone flap was turned and the dura was opened, laser flowmetry probes were placed over surgically undisturbed cortex that was known to be edematous from preoperative CT and MRI scans. Flow index measurements were first made at hypocarbia (PaCO2 = 24.2 +/- 0.9 and 21.5 +/- 2.1 mm Hg for the fentanyl and isoflurane groups, respectively). Minute ventilation was then decreased and cortical flow index was remeasured with PaCO2 = 34.2 +/- 0.6 and 33.0 +/- 0.8 mm Hg for the fentanyl and isoflurane groups, respectively. Hypocarbia during fentanyl-supplemented N2O-O2 anesthesia resulted in a cortical flow index that was 70 +/- 8% of the flow index at near normocarbia (p <0.05). During isoflurane N2O-O2 anesthesia, however, there was a wide variety of responses to hypocarbia, including three patients whose flow indices increased markedly. The mean flow index during hypocarbia was significantly (p <0.05) lower during fentanyl-N2O anesthesia than it was during isoflurane-N2O anesthesia. There was no predictable relationship between the type of brain tumor and the CBF response to hypocapnia during isoflurane-N2O anesthesia. It is concluded that, in edematous brain, cerebral cortical blood flow response to hypocarbia is more likely to be preserved during fentanyl-supplemented N2O-O2 anesthesia than it is during isoflurane-supplemented N2O-O2 anesthesia. In neuropathologic states where hyperventilation is thought to be necessary to reduce cerebral blood flow and decrease brain bulk, isoflurane may be less satisfactory than fentanyl as a supplement to N2O-O2 anesthesia.

Journal Article↗
PubMed1990

Cerebrospinal fluid pressure in patients with brain tumors: impact of fentanyl versus alfentanil during nitrous oxide-oxygen anesthesia.

The effects on the cerebrospinal fluid pressure (CSFP) of alfentanil and fentanyl were compared during nitrous oxide-oxygen (N2O-O2) anesthesia in 24 patients who had brain tumors. Monitored variables included CSFP (lumbar subarachnoid catheter), heart rate from electrocardiographic lead II, mean radial arterial blood pressure, and arterial blood gas tensions. General anesthesia was induced with thiopental, 5 mg/kg IV in divided doses, and maintained with 70% N2O in O2; ventilation was held constant (PaCO2 = 37.4 +/- 1.6 mm Hg [mean +/- SEM]). After baseline data were recorded, 16 subjects were randomly assigned to receive either 5 micrograms/kg fentanyl as an intravenous bolus or 50 micrograms/kg alfentanil as an intravenous bolus, followed by an infusion of alfentanil at 1 micrograms.kg-1.min-1. Monitored variables were continuously recorded for 15 min after opioid injection. A third group of 8 patients was studied subsequently; they received only N2O-O2 during a 15-min observation period and served as controls. Blood pressure was held constant with an intravenous infusion of 0.1% phenylephrine, as needed; noxious stimulation was carefully avoided. Cerebrospinal fluid pressure remained unchanged both in patients who received N2O-O2 alone and in those who received fentanyl-N2O-O2. By contrast, those who received alfentanil-N2O-O2 had a gradual increase in CSFP, reaching 30% above baseline values after 10 min and stabilizing thereafter. Although the absolute increase in CSFP during normocarbic alfentanil-N2O anesthesia was relatively small (9.5 +/- 1.3 mm Hg to 13.0 +/- 1.3 mm Hg [mean +/- SE], P less than 0.05), the absence of a similar effect after fentanyl administration suggests that precautionary measures such as hyperventilation are advisable if alfentanil is used for potentiating normocarbic N2O-O2 anesthesia in neurosurgical patients with intracranial mass lesions.

Adult↗