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Biomedical subjects

E Martin

Publications and source records attributed to E Martin.

At least 289 records · Page 16Linked to original sources
PubMed1997

Posttraumatic stress disorder in patients with traumatic brain injury and amnesia for the event?

Frequency of DSM-III-R posttraumatic stress disorder (PTSD) was studied in 47 active-duty service members (46 male, 1 female; mean age 27 = 7) with moderate traumatic brain injury and neurogenic amnesia for the event. Patients had attained "oriented and cooperative" recovery level. When evaluated with a modified Present State Examination and other questions at various points from study entry to 24-month follow-up, no patients met full criteria for PTSD or met criterion B (reexperience); 6 (13%) met both C (avoidance) and D (arousal) criteria. Five of these 6 also had organic mood disorder, depressed type, and/or organic anxiety disorder. Posttraumatic amnesia following moderate head injury may protect against recurring memories and the development of PTSD. Some patients with neurogenic amnesia may develop a form of PTSD without the reexperiencing symptoms.

Adult↗
PubMed1997

Late glial swelling after acute cerebral hypoxia-ischemia in the neonatal rat: a combined magnetic resonance and histochemical study.

Secondary brain damage after transient cerebral hypoxia-ischemia (HI) is caused by a cascade of cellular events. In this study, complementary methods of magnetic resonance imaging and histochemistry were used to investigate the formation of cytotoxic and vasogenic edema during secondary brain damage induced by transient HI in 7-d-old rats. To elicit injury, 21 rats underwent right common carotid artery ligation followed by 1.5 h of 8% O2 exposure. Sequential apparent diffusion coefficient (ADC) and transversal relaxation time (T2) weighted magnetic resonance imaging were recorded for up to 3 d in 13 7-d-old rats. Eight animals were killed at various intervals between the end of HI and 21 h of recovery to perform histochemical assays using neuronal and astrocytic markers. Changes of the ADC revealed a biphasic function for the evolution of cytotoxic edema during the recovery period. At the end of HI, the ADC in the ipsilateral cortex was significantly decreased. Upon reoxygenation, it returned transiently to normal followed by a secondary, although less pronounced, decline after 8-48 h. After this, the ADC rose steadily. From 8 h of recovery, the proportion of vasogenic edema steadily increased as indicated by the T2 prolongation. At 21 h, the majority of glial cells showed immunoreactivity for glial fibrillary acidic protein and were of larger size, whereas the neurons were apoptotic. These results indicate that the delayed cerebral injury is accompanied by late glial swelling in conjunction with an enlarged interstitial space due to cell damage.

Animals↗
PubMed1997

Prospective longitudinal evaluation of men with initial prostate specific antigen levels of 4.0 ng./ml. or less.

PURPOSE: We evaluated the 3-year longitudinal changes in serial serum prostate specific antigen (PSA) levels in men with an initial PSA of 4.0 ng./ml. or less and no suspicion of prostate cancer. MATERIALS AND METHODS: A total of 760 men with an initial PSA of 4.0 ng./ml. or less plus a normal or suspicious digital rectal examination and a benign prostate biopsy was enrolled into an every 4-month PSA monitoring study. RESULTS: Of the 559 men with an initial PSA of 2.0 ng./ml. or less only 3 (0.5%) had a persistently abnormal PSA for 3 years and 1 cancer (0.2%) was detected, and 48 men had a PSA velocity of 0.8 ng./ml. per year or more at year 1 but only 1 (2%) had a persistent rate of increase (2.4 ng./ml. per year) at 3 years. Of the 201 men with a PSA of 2.1 to 4.0 ng./ml. 85 had an abnormal PSA but only 37 (43%) met the criteria for biopsy. Only 8 of 23 biopsies (35%) revealed cancer. Of the 201 men 24 had a PSA velocity of 0.8 ng./ml. per year or more at year 1 but only 4 had persistence for 3 years. All 4 men had cancer but they were identified as at high risk by PSA criteria. CONCLUSIONS: Men with a PSA of 2.0 ng./ml. or less are at low risk for an abnormal PSA or cancer within 3 years and annual monitoring may not be necessary. However, annual monitoring is clinically useful in men with an initial PSA of 2.1 to 4.0 ng./ml. Also, serial monitoring with interval testing in men whose PSA becomes greater than 4.0 ng./ml. is beneficial in identifying a high risk group requiring biopsy. Finally, PSA velocity did not add further to cancer detection in this population.

Adult↗
PubMed1997

[Carcinoid tumors and neuroendocrine carcinomas of the stomach. Prognosis and therapeutic management. Study of 6 cases].

UNLABELLED: The six reported cases were separated into 2 groups: 1) the tumors of sporadic type, carcinoids (n = 2) and neuro-endocrine carcinomas (n = 2); 2) the gastrin-promoted tumors (n = 2). The purpose of this retrospective study was to review for each group of tumors, the clinicopathologic characteristics, prognosis factors and optimal management. In the first group, patients with a small and well differentiated tumor revealed by digestive bleeding, were treated by wedge excision and are alive and well 24 and 22 years later; the patients with large, invasive and poorly differentiated tumors were treated by subtotal (n = 1) and total (n = 1) gastrectomy, and died 1 year and 3 years later with metastases. In the second group, one patient with a small asymptomatic carcinoid tumor revealing chronic atrophic gastritis, was treated by endoscopic resection, without recurrence 3 years later; another patient with asymptomatic multifocal carcinoid tumors (about 100) associated with Zollinger-Ellison syndrome and multiple endocrine neoplasia type 1, was treated by total gastrectomy and is alive and well 7 years later. No patient had carcinoid syndrome. Synaptophysin was the most sensitive marker and secretion of serotonine was detected in 2 tumors. CONCLUSION: Sporadic carcinoids serotonin and neuro-endocrine carcinomas are life-threatening tumors and need aggressive surgical therapy: their prognosis depends on tumors size, histological differentiation and mostly on tumor extension. In contrast, gastrin-promoted carcinoids do not result in disseminated disease and death, and a rather conservative approach seems appropriate.

Aged↗
PubMed1997

[Genetic risk after high dose radioiodine therapy with regard to gonadal dose].

AIM: The genetic risk for the offspring of patients treated with high doses of radioiodine was to be assessed with special regard to the gonadal dose caused by diagnostic and therapeutic procedures. METHODS: 41 young females (aged between 19 and 39 years) and four young males (aged 26 to 36 years) treated with radioiodine because of a thyroid carcinoma were interviewed by use of a questionnaire. The course of pregnancy and birth history could be documented as well as the congenital and developmental conditions of 56 children. RESULTS: The amount of radioactivity applied for therapy and whole body scans ranged over 4.144 and 35.15 GBq 1-131; the individual gonadal dose was calculated based on the MIRD model and ranged over 0.2 and 2.2 Sv (0.51 Sv at a mean). The period of time between the last radioiodine application and confinement was at least 9 months, not exceeding 14 years. As to the course of pregnancy and birth two early abortions, one extrauterine gravidity and one premature birth due to an insufficiency of the placenta were stated. In one case a chromosomal translocation 7/14 occurred as a genetic defect which lead to an interruption. The children's development was unconspicuous except of two cases of neurodermatitis as well as multiple allergies and an early closure of the anterior fontanelle in one child each. CONCLUSION: Although the genetic risk is supposed to increase with the gonadal dose achieved (doubling dose 1 Sv) and the increased risk of any congenital anomaly was calculated as about 13% at a mean in our patients, the rate of genetic determined diseases was not elevated (1.8% or 1/57). Thus, no increase of genetic defects or congenital malformations was reported in a total of 408 children described in the literature and in our group.

Abortion, Spontaneous↗
PubMed1997

[VDD mode single electrode cardiac stimulation: indications, results and limitations of the method].

UNLABELLED: Several authors have reported the single atrioventricular (AV) electrode, comprising an atrial dipole floating in the right atrium, to be a system capable of providing results which are just as satisfactory as those of conventional systems (DDD). Between August 1992 and March 1995, a VDD single electrode pacemaker was implanted in 65 patients (mean age: 73 years +/- 17.2). The indication for implantation was isolated high degree AVB with no apparent sinus dysfunction. Four pacemakers were used: Vitatron (n = 24), Intermedics (n = 23), Medico (n = 13), Biotronik (n = 5). Intraoperative atrial endocavitary recording was 1.8 mV +/- 0.74. 17 patients died from a cause unrelated to pacemaker dysfunction. 4 patients were lost to follow-up. The remaining 44 patients were reviewed in our centre with a mean follow-up of 14.5 months +/- 7 months. Seven pacemakers (16%) were reprogrammed in VVI or VVI (R) mode, because of permanent atrial fibrillation in 3 cases, complete loss of atrial reception in 2 cases and late onset sinus dysfunction in 1 case. In the 41 patients in sinus atrial rhythm, the atrioventricular synchronization rate was greater than 90% in 88% of patients, equal to 76.3% in 2.4% of patients and atrioventricular synchronization was impossible in 9.6% of cases. CONCLUSION: The overall results of our preliminary experience of VDD mode single electrode pacemaker are moderate. The poor results essentially concerned patients with paroxysmal atrial arrhythmias prior to pacing.

Adolescent↗
PubMed1996

Mapping of catalytic residues in the RNA polymerase active center.

When the Mg2+ ion in the catalytic center of Escherichia coli RNA polymerase (RNAP) is replaced with Fe2+, hydroxyl radicals are generated. In the promoter complex, such radicals cleave template DNA near the transcription start site, whereas the beta' subunit is cleaved at a conserved motif NADFDGD (Asn-Ala-Asp-Phe-Asp-Gly-Asp). Substitution of the three aspartate residues with alanine creates a dominant lethal mutation. The mutant RNAP is catalytically inactive but can bind promoters and form an open complex. The mutant fails to support Fe2+-induced cleavage of DNA or protein. Thus, the NAD-FDGD motif is involved in chelation of the active center Mg2+.

Amino Acid Sequence↗
PubMed1996

Intramolecular inhibition of human defensin HNP-1 by its propiece.

We examined mechanisms that protect host defense cells from their cytotoxic effector molecules. Human neutrophil peptides (HNP) 1-3 are microbicidal and cytotoxic defensins, initially synthesized as 94-amino acid preproHNP(1-94), cotranslationally proteolyzed to proHNP(20-94), then converted by removal of the anionic propiece to mature HNP(65-94)(HNP-1 and -3) and HNP(66-94) (HNP-2). We hypothesized that during synthesis and subcellular sorting the anionic propiece inhibits the cytotoxicity of the cationic defensin. We expressed preproHNP-1 cDNA in recombinant baculovirus-infected insect cells that secreted the normally transient proHNP-1(20-94) into the medium. Cyanogen bromide cleaved proHNP-1(20-94) at the fortuitously located Met64 to yield mature recombinant HNP-1(65-94) and unlinked propiece. Recombinant and native HNP-1 purified from PMN were identical as judged by mass spectrometry, retention time in reverse-phase high performance liquid chromatography, migration on acid-urea polyacrylamide gels, and reaction with a conformation-specific antibody. Recombinant and native HNP-1 had comparable microbicidal activity towards Listeria monocytogenes and were similarly potent in permeabilizing K562 leukemia cells, but proHNP-1(20-94) was virtually inactive in both assays. Addition of unlinked propiece (proHNP-1(20-64) with Met64-->homoserine) inhibited the bactericidal and cell-permeabilizing activity of mature HNP-1 in a dose-dependent manner. Linked, and to a lesser extent unlinked, propiece interfered with the binding of HNP-1 to target cells. The propiece thus acts as an efficient intramolecular inhibitor of defensin HNP-1 cytotoxicity.

Amino Acid Sequence↗
PubMed1996

Brain glucose metabolism is controlled by amplification and desensitization of the neuronal insulin receptor.

Glucose metabolism is essential for brain function and structure. Glucose contributes to the formation of neurotransmitters and is normally the only source for energy formation. There is increasing evidence that brain glucose metabolism is under control of the neuronal insulin/insulin receptor signal transduction. The present data clearly show that intracerebroventricularly administered insulin exerts anabolic effects on cerebral glucose/energy metabolism (amplification of the neuronal insulin receptor complex) whereas cortisol (corticosterone) acts antagonistically (desensitization of the neuronal insulin receptor complex). It is also shown that short-term cortisol (corticosterone) enhanced energy turnover in temporoparietal cortex and hippocampus. In contrast, long-term cortisol (corticosterone) reduced energy turnover in both brain structures studied. This metabolic pattern is reminiscent of that found in very old age. Therefore, it is assumed that long-term cortisol accelerates the aging process in the brain and thus the risk for age-related disorders such as dementia.

Animals↗
PubMed1996

Fatal infection of coronary stent implantation.

Among systemic infections occurring after percutaneous transluminal coronary angioplasty (PTCA) and coronary stent implantation, septic cardiac complications are rare. We report a new case of infective aneurysm of the left anterior descending coronary artery (LAD) following stent implantation. Infective mitral endocarditis due to Pseudomonas aeruginosa occurring a few weeks after stenting led to search for stent infection. Coronary angiography revealed a saccular aneurysm of the LAD. Despite surgical repair, a fatal outcome resulted.

Angioplasty, Balloon, Coronary↗
PubMed1996

Influence of the platelet-activating factor receptor antagonist BN52021 on endotoxin-induced leukocyte adherence in rat mesenteric venules.

The aim of this study was to investigate the influence of the platelet-activating factor (PAF) antagonist BN52021 on endotoxin-induced leukocyte-endothelium interactions and on venular microcirculation. The rates of leukocyte adherence and changes in red cell velocity, volumetric blood flow, vessel diameter, and venular shear rate were monitored in rat mesenteric venules following intravenous lipopolysaccharide (LPS) exposure (15 mg/kg body wt). The experiments were performed in LPS-treated control animals and in animals pretreated with the PAF receptor antagonist BN52021. LPS exposure induced a marked increase in adherent leukocytes in the control group compared to the BN52021-pretreated group. Thirty minutes after LPS injection, 6.1 +/- 0.8 leukocytes were adherent to 100 microns of venule in the control group compared to 2.5 +/- 0.5 in BN52021-pretreated animals (P < 0.01). The increased leukocyte adherence in the control group was accompanied by leukocytopenia. Red cell velocity, volumetric blood flow, vessel diameter, and venular shear rate did not differ between groups, indicating that increased leukocyte adherence in the control group was not due to diminished hydrodynamic dispersal forces. The attenuation of leukocyte adherence by the PAF receptor antagonist BN52021 suggests that PAF is involved in the mediation of the initial process of leukocyte sticking to the endothelium after LPS stimulation.

Animals↗
PubMed1996

Effect of endotoxemia on intestinal villus microcirculation in rats.

Intestinal mucosal hypoperfusion with subsequent ischemia during endotoxemia might cause a breakdown of the gut barrier with translocation of bacteria and their toxins into the systemic circulation, thus maintaining a "gut-derived" septic state. The aim of this study was to investigate the influence of endotoxin on the microcirculation of intestinal villi, which represent the most vulnerable part of the mucosa. The changes in blood flow and in the diameters of the central villus arterioles located in the distal ileum were monitored in control rats without lipopolysaccharide (LPS) exposure (n=7), and in rats receiving 1.5 mg/kg b.w. LPS (n=7) or 15 mg/kg b.w. LPS (n=7) over 60 min. The blood flow and the arteriolar diameters were determined using in vivo videomicroscopy at baseline, and 60 min and 120 min later. In control animals, no change in blood flow and arteriolar diameters were observed during the entire experiment. Administration of 1.5 mg/kg b.w. LPS reduced the blood flow to 69.5 +/- 9.0% of the baseline value at the end of the study period. This decrease in blood flow was associated with a decrease in the villus arteriolar diameters by 17.4 +/- 2.5% from the baseline values. In animals exposed to 15 mg/kg b.w. LPS, the decrease in villus blood flow at 60 min was 64.8 +/- 10.9% of baseline, and at 120 min 66.9 +/- 12.6% of baseline. The diameters of the villus arterioles were reduced by 11.5 +/- 2.4% and 15.1 +/- 1.7%, respectively. In the control group and in the 1.5-mg/kg LPS group, the mean arterial blood pressure did not change during the entire study period. In the 15-mg/kg LPS group, the mean arterial pressure tended to decrease after 60 min. These data suggest a reduction of villus blood flow due to vasoconstriction in the central villus arterioles during normotensive endotoxmia, which might represent the mechanism for the mucosal ischemia observed in critically ill patients.

Animals↗
PubMed1996

Electromyographical and motor performance studies in the pmn mouse model of neurodegenerative disease.

The mouse autosomal recessive mutation progressive motor neuronopathy (pmn) results in early onset motor neuron disease with rapidly progressive hindlimb paralysis, severe muscular wasting, and death at around 6 weeks of age. This mutant provides opportunities for testing novel therapeutic strategies, including the administration of trophic factors, to prevent the degeneration of diseased neurons. The construction of a strain expressing the pmn and the Extra-toe (Xt) phenotypes allows the detection, and therefore the treatment, of affected progeny before the onset of the clinical weakness. Electromyography is the most appropriate technique for a longitudinal study in which a given individual is examined repeatedly. We present the results of an electrophysiological and behavioral exploration of the pmn disease and show that electromyography is a powerful tool for following the course of the disease and evaluating potential therapies relevant to motor neuron diseases.

Action Potentials↗
PubMed1996

Retention of the antibiotic teicoplanin on a hydromer-coated central venous catheter to prevent bacterial colonization in postoperative surgical patients.

OBJECTIVE: Antibiotic-coated intravascular catheters may be an effective means of decreasing bacterial colonization and subsequent catheter-related infection. The present study was designed to investigate the retention of the antibiotic teicoplanin on a hydromer-coated intravenous catheter and the effect of this antibiotic coating on catheter bacterial colonization. DESIGN: A prospective, randomized pilot study. SETTING: Operating rooms (ORs) and an intensive care unit (ICU) at a university hospital. PATIENTS: A consecutive group of 20 male patients undergoing major abdominal surgery. INTERVENTIONS: Control (C; n = 10) or teicoplanin-coated (T; n = 10) single-lumen central venous catheters were inserted before surgery in the OR. Catheters were withdrawn at the discretion of the physicians in the ICU after various periods. MEASUREMENTS: The teicoplanin content of the catheter material was assessed using a bioassay with Bacillus subtilis after complete elution of the antibiotic from the catheter. Bacterial colonization was measured using a quantitative culture technique after the catheter lumen had been flushed and the catheter segments sonicated. MAIN RESULTS: Nearly three-quarters of the initial teicoplanin coating (374 +/- 103 micrograms; mean +/- SD) were released during the first day of catheterization, and after 36 h of intravenous catheterization, no antibiotic was retained on the catheter. No significant difference could be found either in the incidence of bacterial colonization between test (n = 3) and control (n = 4) catheters or in the number of colony-forming units (CFU) on the catheter segments (T, 263 +/- 104 CFU/cm; C, 372 +/- 294 CFU/cm; mean +/- SEM). CONCLUSION: The retention of teicoplanin antibiotic coating on hydromer catheters is only short term if catheters are inserted intravenously. This may limit clinical antibacterial efficacy.

Anti-Bacterial Agents↗
PubMed1996

Semi-continuous versus injectate cardiac output measurement in intensive care patients after cardiac surgery.

OBJECTIVE: Commercially available semi-continuous cardiac output (SCCO) monitoring systems are based on the pulsed warm thermodilution technique. There is evidence that SCCO fails to correlate with standard intermittent bolus cardiac output (ICO) in clinical situations with thermal instability in the pulmonary artery. Furthermore, ventilation may potentially influence thermodilution measurements by enhanced respiratory variations in pulmonary artery blood temperature and by cyclic changes in venous return. Therefore, we evaluated the correlation, accuracy and precision of SCCO versus ICO measurements before and after extubation. DESIGN: Prospective cohort study. SETTING: Intensive care unit (ICU) of a university hospital. PATIENTS AND PARTICIPANTS: 22 cardiac surgical ICU patients. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: SCCO and ICO data were obtained at nine postoperative time points while the patients were on controlled mechanical ventilation. Further sets of measurements were taken during the weaning phase 20 min before extubation, and 5 min, 20 min and 1 h after extubation. SCCO and ICO measurements yielded 286 data pairs with a range of 1.8-9.9 l/min for SCCO and 1.9-9.8 l/min for ICO. The correlation between SCCO and ICO was highly significant (r = 0.92; p < 0.01), accompanied by a bias of -0.052 l/min and a precision of 0.56 l/min. Correlation, accuracy and precision were not influenced by the mode of respiration. CONCLUSIONS: Our results demonstrate excellent correlation, accuracy and precision between SCCO and ICO measurements in postoperative cardiac surgical ICU patients. We conclude that SCCO monitoring offers a reliable clinical method of cardiac output monitoring in ICU patients following cardiac surgery.

Aged↗