Biomedical subjects

A Hager

Publications and source records attributed to A Hager.

At least 19 recordsLinked to original sources

PubMed2006

Myocardial scars determined by delayed-enhancement magnetic resonance imaging and positron emission tomography are not common in right ventricles with systemic function in long-term follow up.

OBJECTIVE: To test the hypothesis that myocardial scars are common in patients with systemic right ventricles. METHODS: 27 consecutive patients with systemic right ventricle were studied with delayed-enhancement magnetic resonance imaging and positron emission tomography. Of the 27 patients, 18 had had an atrial switch operation a mean of 21.8 (SD 4.5) years previously and were 23.4 (SD 5.3) years old. Nine patients without previous heart surgery had congenitally corrected transposition of the great arteries and were 35.3 (SD 15.6) years old. RESULTS: Only one patient had a subendocardial scar identified by delayed-enhancement magnetic resonance imaging. Positron emission tomography identified no myocardial scars. CONCLUSIONS: This study shows that the hypothesis that myocardial scars are common in patients with systemic right ventricles is not correct.

Adolescent↗

PubMed2006

[Intraocular pressure and corneal thickness. A comparison between non-contact tonometry and applanation tonometry].

OBJECTIVE: Corneal thickness and deformation seem to have a considerable influence on intraocular pressure measurement. Due to differences in the corneal deformation in either non-contact tonometry or applanation tonometry, both methods should be compared in the same patient group depending on central corneal thickness. METHODS: In 106 eyes of 55 patients (18 males, 37 females, age 17-89 years, mean 63.3 years) with glaucoma and central corneal thickness between 409 and 644 microm (Orbscan II pachymetry) intraocular pressure was measured in each eye with non-contact tonometry (Reichert AT550) and 30 min later with Goldman applanation tonometry. RESULT: Non-contact tonometry as well as applanation tonometry showed a positive correlation between measured intraocular pressure and corneal thickness. The steepness of the line of regression was 0.33 mmHg per 10 microm of corneal thickness in non-contact tonometry and 0.17 mmHg per 10 microm of corneal thickness in applanation tonometry. CONCLUSION: Independently of the large differences in individual pressure measurements between non-contact tonometry and applanation tonometry, we found higher IOP values with non-contact tonometry in thicker corneas as compared with applanation tonometry. In thinner corneas there was a better correspondence between both methods. Thus, it seems very likely that corneal rigidity increases with corneal thickness.

Adolescent↗

PubMed2006

[Bilateral serous detachment of the neurosensory retina and retinal pigment epithelium with rip of the peripheral pigment epithelium].

HISTORY: A 52-year-old patient with atypical plasmocytoma presented with a bilateral serous detachment of the retina as well as a huge detachment of the pigment epithelium (PE) in the periphery. Shortly thereafter the PE ruptured. In the left eye this led to substantial central macular fibrosis. DIAGNOSIS: The clinically healthy patient showed a nephrotic syndrome; neither typical monoclonality was detectable nor was erythropoiesis or myelopoiesis reduced. THERAPY: To avoid further reduction of VA pars plana vitrectomy (ppV) with silicone oil tamponade and laser coagulation was performed. Clinical findings were reduced significantly and VA was stabilized for 2.5 years. DISCUSSION: PE detachments and serous retinal detachments in patients with nephrotic syndrome are only mentioned in a few cases. However, a peripheral rupture of the PE to this extent seems to be very rare. Early ppV with silicone oil and laser coagulation may prevent further macular fibrosis.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2005

PTPN11 mutations play a minor role in isolated congenital heart disease.

PTPN11 missense mutations cause approximately 50% of Noonan syndrome, an autosomal dominant disorder presenting with various congenital heart defects, most commonly valvar pulmonary stenosis, and hypertrophic cardiomyopathy. Atrioventricular septal defects and coarctation of the aorta occur in 15% and 9%, respectively. The aim of this study was to determine if PTPN11 mutations exist in non-syndromic patients with these two relevant forms of congenital heart disease. The 15 coding PTPN11 exons and their intron boundaries from subjects with atrioventricular septal defects (n = 24) and coarctation of the aorta (n = 157) were analyzed using denaturing high performance liquid chromatography and sequenced if abnormal. One subject with an atrioventricular septal defect but no other known medical problems had a c.127C > T transition in exon 2, predicting a p.L43F substitution. This mutation affected the phosphotyrosine-binding region in the N-terminal src homology 2 domain and was close to a Noonan syndrome mutation (p.T42A). An otherwise healthy patient with aortic coarctation had a silent c.540C > T change in exon 5 corresponding to p.D180D. Our study showed that PTPN11 mutations are rarely found in two isolated forms of congenital heart disease that commonly occur in Noonan syndrome. The p.L43F mutation belongs to a rare class of PTPN11 mutations altering the phosphotyrosine-binding region. These mutations are not predicted to alter the autoinhibition of the PTPN11 protein product, SHP-2, which is the mechanism for the vast majority of mutations causing Noonan syndrome. Future studies will be directed towards understanding these rare phosphotyrosine binding region mutants.

Adolescent↗

PubMed2005

[Anatomical and functional results after elective macular surgery].

PURPOSE: The purpose of this paper is to assess the anatomical and functional results after macular surgery in a large group of patients. METHODS: Between June 1995 and December 2001, 381 eyes underwent vitreous surgery for macular pucker (n=244) or macular holes (n=137) with a standard pars plana vitrectomy (PPV) with induction of posterior vitreous separation, membrane peeling, peeling of the internal limiting membrane (no ICG staining was used), and gas instillation (SF(6)). RESULTS: A second surgical intervention due to vision-threatening complications after PPV had to be performed in 8 of 381=2.1%. In the macular pucker group, metamorphopsias improved in 46.6% and the median of visual acuity (VA) improved from preoperative 0.3 to postoperative 0.5. Hole closure of macular holes was obtained in 92.2%; the median of VA improved in this group from preoperative 0.2 to postoperative 0.4. CONCLUSION: In our group a second vitreoretinal procedure due to vision-threatening complications had to be performed in 2.1%. Compared to the spontaneous course, PPV for macular pucker or macular hole has a very positive influence on functional parameters.

Aged↗

PubMed2005

[Theoretical basis of goldmann applanation tonometry].

For more than 50 years Goldmann applanation tonometry has been the internationally accepted method for measuring intraocular pressure. In Goldmann applanation tonometry, however, some basic physical properties are oversimplified and the method has some flaws and restrictions. This paper is intended to promote the understanding of the methodological basis of Goldmann applanation tonometry and describes the most important factors influencing the measurement of intraocular pressure (e. g., corneal thickness, corneal radius, axial length and corneal morphology). Furthermore, the basic principles of other commonly used tonometer devices will be discussed. New developments are anticipated that will measure the true intraocular pressure more accurately than Goldmann applanation tonometry.

Equipment Design↗

PubMed2005

Comparison of health related quality of life with cardiopulmonary exercise testing in adolescents and adults with congenital heart disease.

OBJECTIVES: To compare self reported quality of life with measured exercise capacity in patients with congenital heart disease. DESIGN: Prospective cross sectional clinical study. SETTING: Tertiary referral centre for congenital cardiology. PATIENTS AND METHODS: 149 patients (60 female, 14-60 years old) with various congenital heart defects completed a health related quality of life questionnaire (medical outcomes study 36 item short form). Then they performed a cardiopulmonary exercise test on a bicycle in a sitting position. RESULTS: Peak oxygen uptake correlated significantly with the physical functioning (r = 0.521, p < 0.0005) and general health scales (r = 0.313, p < 0.0005) but not with role-physical, bodily pain, vitality, social functioning, role-emotional, mental health, and health transition scales. Closer examination of the data showed that despite an overall good correlation a substantial number of patients overestimated their physical capabilities. CONCLUSIONS: Exercise tests and quality of life instruments should be used together to get an appropriate overview of the health status of patients with congenital heart disease.

Adolescent↗

PubMed2004

[Vitreoretinal secondary procedures following elective macular surgery].

OBJECTIVE: The spectrum of reoperations after macular surgery was investigated retrospectively in a large group of patients. All secondary surgical procedures except for cataract surgery were considered. METHODS: Between July 1995 and June 2001 353 eyes underwent macular surgery (218 due to macular pucker, 135 due to macular hole) with a pars-plana vitrectomy (PPV), creation of vitreous detachment, membrane peeling and SF(6)/air-instillation. The vitrectomies were performed by 4 different surgeons. In all patients a preoperative circular peripheral cryoretinopexy was performed 3-4 weeks before macular surgery. The follow-up was 20.9 months on average. The number of revitrectomies as well as the postoperative retinal detachment rate were investigated. RESULTS: In 33 cases (9.3%) a second vitrectomy had to be performed due to an unsatisfying postoperative macular finding: 17/218 (7.8%) after macular pucker surgery with a recurrent pucker and 16/135 (11.8%) after macular hole surgery with persistent or recurrent macular hole. In 7/353 (2.0%) a postoperative rhegmatogenous retinal detachment was observed and in 2/353 (0.6%) a postoperative endophthalmitis had to be treated. CONCLUSION: In 9.3% of our patients a second PPV due to an unsatisfying macular finding became necessary. The rate of postoperative retinal detachment of 2.0% is considerably lower than in most other studies. Therefore, a possible prophylactic effect of the preoperative circular peripheral cryoretinopexy is suggested to reduce the risk of postoperative retinal detachment.

Elective Surgical Procedures↗

PubMed2004

Oxidative study of patients with total body irradiation: effects of amifostine treatment.

In patients undergoing bone marrow transplant (BMT), reactive oxygen species (ROS) are released as a consequence of the events related to the preparative regimen. Total body irradiation (TBI), which is known to generate ROS, is a routine preconditioning procedure prior to BMT. Several studies have demonstrated that amifostine protects normal tissues. In the present report, we investigated the oxidative state of plasma and erythrocytes in 21 patients with hematological malignancies undergoing TBI. The dose fraction was 160 cGy, twice daily (eight sessions). For ROS detection, we used electron spin resonance spectroscopy and spin-trapping technique. In all, 15 patients received amifostine prior to the irradiation and six did not. No free radical signal was detected in the plasma samples spectrum of 15 amifostine-treated patients, and five of six samples of nontreated patients showed ROS signal. Only two of 15 treated patients had mucositis degree higher than 2, whereas five of six nontreated patients suffered this complication. The average hospitalization days in treated and nontreated patients were 23.5 and 29.7, respectively. This work represents an original observation; we found by direct measurements of free radicals that ROS are released during TBI, and confirmed the amifostine radical scavenger activity.

Adolescent↗

PubMed2003

Impaired myocardial blood flow and coronary flow reserve of the anatomical right systemic ventricle in patients with congenitally corrected transposition of the great arteries.

OBJECTIVES: To investigate myocardial blood flow of the morphological right systemic ventricle in unoperated patients with congenitally corrected transposition of the great arteries (CCTGA) by positron emission tomography (PET). DESIGN: Prospective cross sectional clinical study. SETTING: Tertiary referral centre for paediatric cardiology. PATIENTS: 15 patients with CCTGA were investigated by PET with nitrogen-13 ammonia at rest and during adenosine vasodilatation. A subgroup of seven patients had isolated CCTGA (group A, mean (SD) age 30.3 (11.9) years) and the remaining eight patients had complex CCTGA associated with subpulmonary stenosis; four of this second group also had ventricular septal defect (group B, mean (SD) age 30.6 (16.4) years). Eleven healthy adults (mean (SD) age 26.2 (5.1) years) served as the control group. RESULTS: Resting myocardial blood flow was not different between both groups of patients with CCTGA and the controls. Hyperaemic blood flows were significantly lower in both groups of CCTGA than in the control group (mean (SD) 195 (21) ml/100g/min in group A, 201 (27) ml/100g/min in group B, 309 (74) ml/100g/min in the control group; p < 0.001). Thus, coronary flow reserve was significantly lower in both groups of CCTGA than in the control group (mean (SD) 2.5 (0.28) in group A, 2.6 (0.48) in group B, and 4.0 (0.73) in the control group; p < 0.001). CONCLUSION: Blood flow measurements suggest that coronary reserve is decreased in the absence of ischaemic symptoms in patients with CCTGA. The global impairment of stress flow dynamics may indicate altered global vasoreactivity, and quantitative changes in microcirculation suggest that their role in the pathogenesis of systemic right ventricular dysfunction is important.

Adenosine↗

PubMed2001

Changes in reactive oxygen species (ROS) production in rat brain during global perinatal asphyxia: an ESR study.

A large body of evidence suggests that the production of reactive oxygen species (ROS) can play an important role in ischemic neuronal injury. However any studies has been performed in hypoxic conditions. In the present experiments we studied using electron spin resonance (ESR) techniques the ROS release in neostriatum of newborn rats subjected to acute perinatal asphyxia (PA) followed by various periods of reoxygenation. Pregnant rats' uteri still containing foetuses were taken out and subjected to PA by immersion in a 37 degrees C water bath during the following periods of time: 5, 10, 15, 19 and 20 min. After performing PA, animals were recovered and ROS measured after 0, 5, 15, 30 or 60 min of reoxygenation. Then, pups were sacrificed, their neostriatum removed and homogenised with N-tert.-butyl-alpha-phenylnitrone (PBN) and diethylenetriamine-pentacetic acid (DPTA) in phosphate-buffered saline (PBS) and the formed complexes were extracted with ethyl acetate an analysed using an X-band ESR spectrometer. A significant release of ROS was detected at 19 and 20 min of PA after 5 min of reoxygenation. These data provide strong evidence that ROS could be involved in neuronal damage during PA.

Animals↗

PubMed2001

P25 and P28 proteins of the malaria ookinete surface have multiple and partially redundant functions.

The ookinete surface proteins (P25 and P28) are proven antimalarial transmission-blocking vaccine targets, yet their biological functions are unknown. By using single (Sko) and double gene knock-out (Dko) Plasmodium berghei parasites, we show that P25 and P28 share multiple functions during ookinete/oocyst development. In the midgut of mosquitoes, the formation of ookinetes lacking both proteins (Dko parasites) is significantly inhibited due to decreased protection against lethal factors, including protease attack. In addition, Dko ookinetes have a much reduced capacity to traverse the midgut epithelium and to transform into the oocyst stage. P25 and P28 are partially redundant in these functions, since the efficiency of ookinete/oocyst development is only mildly compromised in parasites lacking either P25 or P28 (Sko parasites) compared with that of Dko parasites. The fact that Sko parasites are efficiently transmitted by the mosquito is a compelling reason for including both target antigens in transmission-blocking vaccines.

Animals↗

PubMed2001

[Conventional ablation surgery or primary vitrectomy in complicated retinal holes].

BACKGROUND: We retrospectively evaluated 100 difficult cases out of 803 consecutive eyes with retinal detachment in order to determine the best surgical procedure in cases with difficult break configurations such as multiple, large, and central holes. METHODS: We treated the eyes either with conventional buckling surgery (n = 60) encircling buckle (EB) plus sponge exoplant (SP) (n = 45) or multiple sponge exoplants (n = 15) or with primary vitrectomy (PV) (n = 40). From the 40 patients in the PV group, 10 underwent vitrectomy plus intraocular gas only, in the other cases an encircling band was used (n = 30). RESULTS: In the EB/SP group the retina was attached directly after surgery in 59/60 cases. During a mean follow-up of 14.5 months redetachment occurred in 4/60 cases. In the PV group the retina was attached in 37/40 cases after resorption of gas and during the mean follow-up of 9.3 months redetachment occurred in an additional 4/40 cases. Complications during surgery in the EB/SP group were retinal incarceration (n = 2) and subretinal hemorrhage (n = 2). In the PV group intraoperative complications included choroidal detachment (n = 1) and iatrogenic holes (15%). Postoperative complications were choroidal detachment in 6/60 vs 0/40, transitory increased intraocular pressure (30% vs 68%). Double vision, however correctable by means of prisms, occurred in 4/60 vs 0/40. CONCLUSIONS: The primary attachment rate is high and similar with both procedures. The spectrum of intra- and postoperative complications is however different between both groups.

Aged↗

PubMed2001

Zinc and diabetes mellitus: is there a need of zinc supplementation in diabetes mellitus patients?

Diabetes mellitus is a group of metabolic disorders, the incidence of which varies widely throughout the world. The treatment of diabetes mellitus includes insulin, oral antidiabetic agents, and dietary regimens. Although the emphasis is on macronutrients intakes, there is strong evidence that there is an abnormal metabolism of several micronutrients in diabetic individuals. Zinc is one of the essential micronutrients of which status and metabolism is altered in this condition. This work is a short review about the close relation among zinc, glucose metabolism, and insulin physiology, as well as about the few experimental data about zinc absorption and zinc supplementation in diabetes mellitus patients.

Diabetes Complications↗

PubMed2000

Bioavailability, biodistribution, and toxicity of BioZn-AAS(1): a new zinc source. comparative studies in rats.

Food fortification with a proper zinc compound is an economic and effective strategy to prevent zinc deficiency. BioZn-AAS, a zinc gluconate stabilized with glycine, was compared with zinc sulfate (reference standard), zinc hydroxide, and zinc gluconate, all of them labeled with (65)Zn. This preclinical study was performed on Sprague-Dawley rats of both sexes, and the administered dose was 85 microg/kg of zinc. Bioavailability studies showed that absorption of BioZn-AAS was not statistically different than absorption from other sources in female rats (25.65% +/- 2.20% for BioZn-AAS, 28.24% +/- 4. 60% for ZnSO(4), 24.91% +/- 4.02% for Zn[OH](2), and 25.51% +/- 2. 70% for Zn-gluconate). In the case of the male rats, absorption of BioZn-AAS (27.97% +/- 4.20%) was higher (P<0.05) than that from the other compounds (23.15% +/- 2.90% for ZnSO(4), 22.62% +/- 3.90% for Zn[OH](2), and 22.30% +/- 3.90% for Zn-gluconate). Biodistribution studies demonstrated that the zinc from BioZn-AAS followed the same metabolic pathway as zinc from the other sources. Toxicity studies were performed with 50 female and 50 male rats. The value of oral lethal dose 50 (LD(50)) was 2000 mg/kg for female rats and 1900 mg/kg for male rats. Therefore, we conclude that BioZn-AAS has adequate properties to be considered a proper zinc compound for food fortification or dietary supplementation.

Absorption↗

PubMed2000

99mTc-ENS ventilation scintigraphy: preliminary study in human volunteers.

Exogenous natural surfactant (ENS) labeled with (99m)Tc ((99m)Tc-ENS, 900-1110 MBq), a new radiopharmaceutical for ventilation scintigraphy, was nebulized during 3 min to five volunteers. For comparative purposes, (99m)Tc-diethylenetriamine pentaacetic acid (DTPA) was studied in the same way. (99m)Tc-ENS images were of at least the same quality as (99m)Tc-DTPA images. However, in smoking volunteers, the (99m)Tc-DTPA images show some areas that seemed to be not well-ventilated, although these areas appeared well-ventilated when the study was performed with (99m)Tc-ENS. These results suggest that (99m)Tc-ENS can be used for ventilation scintigraphy to allow the observation of some areas that cannot been visualized using (99m)Tc-DTPA as ventilation agent.

Adult↗

PubMed2000

Zinc status and immune system relationship: a review.

The essentiality of zinc for humans was first documented by Prasad in the 1960s. The main clinical manifestations associated with zinc deficiency are growth retardation, hypogonadism, diarrhea, and increased susceptibility to infectious diseases. Thus, in the past 25 yr, there was an increased interest of researchers in studying the role of zinc in human immunity. Although mechanistic research has been carried out using animal models, there are several studies in humans with similar results. This work is an attempt to review the information available in this field to understand the important role that zinc plays in the normal development and function of the immune system.

Aged↗

PubMed1999

[Photodynamic therapy: ICG angiography findings].

PURPOSE: Photodynamic therapy (PDT) has been shown to provide immediate occlusion of choroidal neovascularization (CNV), followed by recurrent leakage after single PDT in the majority of the cases after 3 months. Indocyanine green angiography (ICG-A) was used to evaluate completeness of CNV occlusion, effects on physiological choroid and patterns of CNV recurrence. METHODS: ICG-A was performed using a confocal laser scanning ophthalmoscope (HRA) before PDT at 1 week, 4 and 12 weeks following PDT. Twenty patients with single and 10 patients with repeated PDT treatments with administration of benzoporphyrin derivative and radiant exposures between 50 and 150 J/cm2 were evaluated. RESULTS: Before PDT well-defined CNV was detectable during early ICG-A in all lesions. Depending on the number of treatments, CNV was absent in early phase ICG-A in 46-83%. CNV reappeared at week 4 in many and at 12 weeks in 77 (66%) of the cases. The treated area regularly showed hypofluorescence, which persisted until week 12. The intensity of choroidal hypofluorescence showed wide interindividual variability. Recurrence may originate from persistent feeder vessels. CONCLUSION: With ICG-A we demonstrated that PDT induces hypofluorescence of CNV and choroid possibly due to perfusion changes or blockade phenomena. Recurrence may be due to reperfusion of the preexisting CNV or regrowth from feeder vessels.

Adult↗