Biomedical subjects

B Jacob

Publications and source records attributed to B Jacob.

At least 19 recordsLinked to original sources

PubMed2002

T cell reactivity in neonates from an East and a West German city--results of the LISA study.

BACKGROUND: Within an ongoing birth cohort study (LISA) the cytokine production of cord blood T cells was compared between neonates from Leipzig (East Germany) and Munich (West Germany). The aim of this study was to analyse regional differences and influencing factors of the immune status. METHODS: Cytokine production was measured in a randomly selected subgroup of 158 children from the LISA (Life style - Immune system - Allergy) cohort by intracellular cytokine staining. Information on family "atopy" history (FAH) and home characteristics was obtained from questionnaires. RESULTS: Reduced numbers of interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) producing T cells were found in association with biparental FAH and housing renovation during pregnancy. In addition, cytokine production was influenced by season. In Munich, the frequency of biparental FAH and of renovation measures during pregnancy was significantly higher as compared to Leipzig. Neonates from Munich showed significantly decreased amounts of IFN-gamma and TNF-alpha and elevated levels of interleukin-4 (IL-4) producing T cells. Differences in cytokine production between Munich and Leipzig were influenced by season (IL-4) and housing renovation (IFN-gamma, TNF-alpha). CONCLUSIONS: Since differences in the T cell cytokine production of neonates in Munich and Leipzig are independent from FAH our findings may provide evidence for the impact of environmental factors upon the fetal immune system.

Cohort Studies↗

PubMed2002

[Iniencephaly: four cases and a review of the literature].

Iniencephaly is a rare malformation of the base of the skull. The brain is involved and prognosis is almost invariably lethal. We identified 202 reports in the literature up through 2000. Ultrasound morphology explorations now provide the diagnosis making it possible to propose pregnancy termination. We report four cases of iniencephaly diagnosed between 1992 and 1999.

Abnormalities, Multiple↗

PubMed2002

[Iniencephaly and early prenatal diagnosis].

Iniencephaly is a rare malformation of the base of the skull. The brain is involved and prognosis is almost invariably lethal. Diagnosis is now possible with morphologic ultrasound, and lead to propose induced abortion. We describe a new case report with early prenatal diagnosis that allowed induced abortion at the term of 14 weeks.

Adult↗

PubMed2002

[Dysfunction of the magnocellular pathway in Alzheimer's disease].

Visual disturbances are a common feature of Alhzeimer's disease. They are related primarily to visuo-spatial deficits. The pathways mediating visuo-spatial and form identification are at least partially segregated in the brain. The magnocellular pathway has characteristics which make it more suitable for detecting dynamic form, motion and depth. We assessed by means of psychophysical and electrophysiological testings the properties of the parvo and the magnocellular pathways. We found contrast sensitivity deficits for the low and middle spatial frequencies, a significant reduction of the amplitude of the steady-state pattern VEP's at 16, 20 and 24 Hz, abnormal transient pattern VEP's only for the major positivity (P100) and abnormal flash VEP's (delayed P2) as previously observed. The temporal frequency deficits and other abnormalities pointed out in this study, could be related to a dysfunction of the M-pathways in Alzheimer's disease.

Aged↗

PubMed2001

Double scaling and intermittency in shear dominated flows.

The nature of intermittency in shear dominated flows changes with respect to homogeneous and isotropic conditions since the process of energy transfer is affected by the turbulent kinetic energy production associated with the Reynolds stresses. For these flows, a new form of refined similarity law is able to describe the increased level of intermittency. Ideally a length scale associated with the mean shear separates the two ranges, i.e., the classical Kolmogorov-like inertial range, below, and the shear dominated range, above. In the present paper we give evidence of the coexistence of the two regimes and we support the conjecture that the statistical properties of the dissipation field are practically insensible to the mean shear. This allows for a theoretical prediction of the scaling exponents of structure functions in the shear dominated range based on the known intermittency corrections for isotropic flows. The prediction is found to closely match the available numerical and experimental data. The analysis shows that the larger anisotropic scales of shear turbulence display universality, and determines the modality by which the dissipation field fixes the properties of turbulent fluctuations in the shear dominated range.

Journal Article↗

PubMed2001

Xenotransplantation of parathyroids in rats using barium-alginate and polyacrylic acid multilayer microcapsules.

The integrity and function of encapsulated parathyroid tissue following xenotransplantation is limited by oxygen and nutrition supply and capsule fibrosis. Since some of these factors depend on stability and biocompatibility of the coating material, multilayer microcapsules have been developed. Parathyroid tissue pieces and digested single cells from pigs were encapsulated in barium-alginate and in polyacrylic acid (PAA) multilayer capsules. After 7 days of culture the function of the encapsulated cells were assessed. Subsequently, in a part of the cultured microcapsules the viability was directly assessed whereas the other part was transplanted in dark animal [DA] rats for 30 days. After explantation viability and fibrotic reaction were examined. Single cells showed a significant increase in parathyroid hormone [PTH] secretion when exposed to medium low in calcium, whereas minced tissue pieces revealed necrosis without stimulatory responsiveness. Morphometry showed significantly better viability of single cells compared with minced tissue in vitro and in vivo. The fibrotic reaction against capsules with minced tissue was more pronounced than for capsules containing single cells. There was no difference between barium alginate and PAA capsules when containing minced tissue. In single cells, however, the fibrous tissue reaction differed significantly between barium alginate and PAA capsules. Encapsulated single cells of parathyroid tissue maintain detectable function and viability. In contrast minced tissue underwent necrosis and induced significantly more connective tissue reaction than single cells indicating an interrelationship between necrosis and fibrosis.

Acrylic Resins↗

PubMed2001

Respiratory symptoms in relation to indoor exposure to mite and cat allergens and endotoxins. Indoor Factors and Genetics in Asthma (INGA) Study Group.

The authors investigated the relationship between respiratory symptoms in adults and exposure to mite and cat allergens, the role of endotoxins in house dust, the effects of mixtures of several allergens, and interactions between allergen exposure and allergic sensitization. Within a nested case-control study, 405 subjects aged 25-50 yrs from two German cities answered a standardized questionnaire. Allergen-specific immunoglobulin-E was measured. Dust samples were taken from the subjects' homes to determine exposure to mite (Dermatophagoides pteronyssinus antigen 1 Der p 1) and (D. farinae antigen 1 Der f l) and cat (cat antigen d1 Fel d 1) allergen and endotoxin content in settled house dust. Exposure to Der f 1 and Der p 1 plus Der f 1 >10 microg x g(-1) of mattress dust, respectively, increased the risk of wheeze and breathlessness (odds ratios (OR): 4.04, 95% confidence interval (CI): 1.53-10.64, OR: 2.78, 95% CI: 1.06-7.28). Fel d 1 >8 microg x g(-1) was positively associated with cough at night (OR: 2.74, 95%, CI: 1.22-.17), noteworthy also in the nonsensitized subjects. Subjects exposed to elevated concentrations of more than one allergen had an up to seven-fold increase in the risk of respiratory symptoms, compared to nonexposed subjects. Sensitized subjects exposed to elevated concentrations of Der f 1 or Fel d 1 were found to have the highest risk of asthma attacks and respiratory symptoms. No statistically significant association was found between exposure to endotoxins and respiratory health. Indoor exposure to Dermatophagoides farinae antigen 1 and cat antigen d1 is a risk factor for respiratory symptoms in adults, and for cat antigen d 1 even in nonsensitized subjects. The risk is increased if subjects are exposed to a mixture of allergens or if they are sensitized in addition to high exposure.

Adult↗

PubMed2000

The effect of low-level blood lead on hematologic parameters in children.

A health survey of school children living in polluted regions of eastern Germany provided us with data necessary to examine the effects of lead on the blood system at levels below current standards for blood lead content. Data collected for 797 children, aged 5-14 years, with low blood lead levels (GM, 33.3 microg Pb/L; range, 7.5-239 microg Pb/L) allowed us to examine the relationship between blood lead content and hematological parameters. Using linear regression analyses and controlling for a number of potential confounding factors, we found that increasing blood lead levels by 10 microg/L were associated with a small increase in the number of red blood cells and in girls with reduced MCV and MCH. The reasons for our observation, especially the gender difference, are still uncertain. In conclusion the morphology and function of erythrocytes might be sensitive parameters of low dose lead toxicity.

Adolescent↗

PubMed2000

Effect of media composition on long-term in vitro stability of barium alginate and polyacrylic acid multilayer microcapsules.

For a number of applications stability of microcapsules is a critical factor. Since the maintenance of polyelectrolyte complexes depends considerably on the ion composition we tested the physical properties of barium alginate capsules and searched for conditions to improve stability by a multilayer coating with polyethylenimine (PEI) and polyacrylic acid (PAA). Mechanical stability and diameters were determined in barium alginate capsules and compared with multilayer capsules. Multilayer coating resulted in smaller capsules than barium complexing alone. The difference was more pronounced when CaCl2 was used instead of NaCl during coating. Barium alginate capsules and application of CaCl2 during coating led to continuous pressure profiles, whereas NaCl resulted in bursting at a defined pressure, indicating the additional contribution to mechanical stability by the outer layers. After 7 d culture, mechanical stability of coated capsules decreased in RPMI and NaCl but was most pronounced in sodium citrate. The capsule diameter increased in sodium citrate, less pronounced in NaCl and was significantly different to RPMI and double distilled water. During long-term culture in RPMI, the diameter increased and mechanical stability decreased significantly. Multilayer coating improved mechanical stability which was impeded most in sodium citrate, to a lesser extent by NaCl and RPMI even after long-term exposure.

Acrylic Resins↗

PubMed2000

Gas cooking, respiratory health and white blood cell counts in children.

The use of gas stoves has been associated with respiratory symptoms of chronic airway inflammation and higher rates of respiratory infections. We used data from a 1992/93 survey of 2,198 East German school children (aged 5 to 14) to assess whether gas cooking increases respiratory symptoms and is associated with a chronic inflammatory process reflected by an increase in white blood cell (WBC) count in children who do not exhibit signs of an acute respiratory infection. We found increases for the respiratory symptoms 'cough without cold' [odds ratio (OR) = 1.68; 95% confidence interval (CI), 1.18-2.39], 'cough in the morning' (OR = 1.58; CI, 1.23-2.04) and 'cough during the day or at night' (OR = 1.42; CI, 1.13-1.78) in children living in homes with gas ranges, but lifetime prevalence of asthma, bronchitis, wheeze, and the prevalence of acute infections were not affected. Furthermore, we examined WBC levels in a subgroup of 1,134 children for whom blood samples were available and who did not suffer from an acute infection. We observed small increases in the risk of having WBC counts above the 75th or 90th percentile (8300 or 9800 cell counts per microliter) when children were exposed to gas cooking after adjustment for age, gender, and passive smoking (OR = 1.30; CI, 0.98-1.73, and OR = 1.38; CI, 0.91-2.10). The strongest effect estimates for chronic inflammation were found for those children likely to have been exposed at higher levels, that is when stoves had no fans, in smaller homes, and for children spending more time indoors.

Adolescent↗

PubMed1999

Trends in allergies among children in a region of former East Germany between 1992-1993 and 1995-1996.

A lower prevalence of asthma and allergies has been reported among children and adults living in the area of former East Germany compared with those living in West Germany. After German reunification in 1990, the East German population rapidly adopted a western lifestyle. Therefore, this study examined if the prevalence rates of allergic diseases, symptoms, and sensitisation and asthma have increased among East German children since German reunification. - Children aged 5 to 7 years living in the region of Sachsen-Anhalt, East Germany were examined in two cross-sectional studies during 1992-93 (n = 769, response rate 84.0%) and 1995-96 (n = 725, response rate 74.6%). Sensitisation was assessed by specific immunoglobulin E measurements against five common aeroallergens using the CAP-FEIA technique. After adjustment for sex, parental education, season of examination, day care attendance, breast feeding, environmental tobacco smoke exposure, cat dander exposure, and several indoor factors, an increase in the prevalence of self-reported, physician-diagnosed allergies (OR 1.44, 95% CI 1.01-2. 06), but not in allergic sensitisation (OR 0.85, 95% CI 0.62-1.16) was found. The only evidence of an increase in allergies of the self-reported increase in the prevalence of physician-diagnosed allergies is likely due to changes in physician diagnostic patterns and the heightened public awareness of allergic diseases. - In conclusion, there were no significant changes in the prevalence of asthma, allergic rhinitis, or self-reported symptoms of allergic diseases.

Adult↗

PubMed1999

Myocardial ischemia and weaning failure in patients with coronary artery disease: an update.

OBJECTIVE: To determine the frequency and effects of weaning-related myocardial ischemia on weaning outcomes in patients with coronary artery disease. DESIGN: Prospective cohort study. SETTING: Medical and cardiac intensive care units of a 300-bed teaching community hospital. MEASUREMENTS AND MAIN RESULTS: Three-lead ST segments, heart rate-systolic blood pressure products, and respiratory rate/tidal volume ratios were obtained for patients with coronary artery disease just before and during their initial trials of weaning from mechanical ventilation. ST segments were interpreted by a blinded cardiologist. Eighty-three patients with a mean age of 72.4 +/- 1.1 years (mean +/- SEM), a mean Acute Physiology and Chronic Health Evaluation II score of 16.4 +/- 0.8, and a mean duration of mechanical ventilation of 4.6 +/- 0.9 days were studied. Eight patients showed electrocardiographic evidence of ischemia during weaning, and seven of these patients failed to be liberated on their first day of weaning. The presence of ischemia significantly increased the risk of weaning failure (risk ratio, 2.1; 95% confidence interval, 1.4-3.1). The rate-pressure product for the group as a whole increased significantly during weaning, from 11.9 +/- 0.4 to 13.5 +/- 0.5 mm Hg x beats/min x 10(3) (p < .01). The increase in rate-pressure product tended to be greater in patients who became ischemic (12.8 +/- 0.9 to 17.3 +/- 2.0 mm Hg x beats/min x 10(3)) than in patients who were not ischemic during weaning (11.8 +/- 0.4 to 13.0 +/- 0.5 mm Hg x beats/min x 10(3); p = .05). The rate/volume ratio did not change significantly during weaning, but the rate/volume ratios after both 1 min (65.6 +/- 4.6 vs. 98.0 +/- 9.4 breaths/min/L; p < .05) and 30 mins (68.6 +/- 4.3 vs. 91.1 +/- 8.9 breaths/min/L; p < .05) of unassisted breathing were lower in successful than in unsuccessful patients. CONCLUSION: Electrocardiographic evidence of myocardial ischemia occurs frequently and is associated with significantly increased risk of first-day weaning failure in patients with coronary artery disease.

APACHE↗

PubMed1998

Restricted and regulated overexpression reveals calcineurin as a key component in the transition from short-term to long-term memory.

To investigate the roles phosphatases play in hippocampal-dependent memory, we studied transgenic mice overexpressing a truncated form of calcineurin. These mice have normal short-term memory but defective long-term memory evident on both a spatial task and on a visual recognition task, providing genetic evidence for the role of the rodent hippocampus in spatial and nonspatial memory. The defect in long-term memory could be fully rescued by increasing the number of training trials, suggesting that the mice have the capacity for long-term memory. We next analyzed mice overexpressing calcineurin in a regulated manner and found the memory defect is reversible and not due to a developmental abnormality. Our behavioral results suggest that calcineurin has a role in the transition from short- to long-term memory, which correlates with a novel intermediate phase of LTP.

Animals↗

PubMed1998

[Lewy body dementia].

Dementia with Lewy Bodies (DLB) is an entity which now fulfils clinical and neuropathological criteria according to international consensus guidelines (McKeith et al., 1996). It is now possible, in clinical practice, to consider the diagnosis of DLB from the beginning of the management of a demented patient. The clinical, diagnostic and therapeutic aspects of DLB are investigated in a prospective manner. Visual hallucinations, fluctuations and extrapyramidal symptoms seem to have, in association with the progressive cognitive decline, some particularities. However their specificity should be correlated with neuropathological data. Other symptoms, such as repeated falls or syncope, neuroleptic sensitivity, systematized delusions or other modalities of hallucinations, are probably additional arguments giving more predictive value to the association of the major symptoms. The role of neuropsychological patterns at the beginning of the cognitive decline is shown. There are some recent concordant results of functional imaging in DLB. The neuropathological aspects of DLB and the links with Parkinson pathology and especially Alzheimer pathology are emphasized.

Humans↗

PubMed1998

[Memory complaints: what should be done? From consultation to the memory center].

Memory complaints are frequent and not always the result of a memory impairment. Such complaints must be taken into account since they always reflect some disorder, at least of attentional processes. Excepting primary psychiatric disorders, biological and imaging exams are required in addition to a neuropsychological and behavioral assessment. Finding the cause of the memory complaints is not an end in itself. The purpose is to cure or at least to relieve the consequences of this and related symptoms with pharmacological, neuropsychological and psychological therapies, social help, information and support. Patients (especially in case of dementia) and families need follow-up care by a multidisciplinary staff (neurologists, psychiatrists, psychologists, speech therapists, nurses, nurse's aids and social workers) who play a role of prevention for intercurrent diseases, social and legal counselling and help anticipate the future. Multidisciplinary memory units are dedicated to the diagnosis and care of memory complaints and disorders. We describe here the operative function of these centers which should be integrated into a health care network centered around patients with memory complaints and their families.

Ambulatory Care Facilities↗

PubMed1997

Medial temporal lobe atrophy in memory disorders.

Medial temporal lobe atrophy determined by temporal lobe oriented computed tomography (CT), 1 year before death, is strongly associated with histopathologically confirmed Alzheimer's disease (AD). The aim of this study was to assess the diagnostic accuracy of medial temporal lobe measurement for the diagnosis of AD in patients referred to a memory disorders clinic, especially those at an early stage of the disease. CT oriented to the temporal lobe was performed in 333 subjects aged 41-93 years consecutively recruited in a Memory Disorders Clinic: 124 had probable AD, Mini Mental State score (MMS) = 17 (8); 50 possible AD [MMS = 21 (5)]; and 119 patients had miscellaneous memory disorders [MMS = 22 (7): frontotemporal lobe dementia, subcortical dementia, cortical Lewy body disease, vascular dementia, Korsakoff syndrome, focal atrophy, etc.]. There were also 19 anxious/depressed patients [MMS = 29 (1)] with normal performance on memory tests, and 21 controls. The minimum width of the medial temporal lobe was measured. The best cut-off to distinguish AD patients from non-AD patients was 11.5 mm, in agreement with data in the literature. At this threshold, 84% of probable AD patients had a positive test and 90% of controls and anxious/depressed patients had a negative test. For the diagnosis of probable AD, sensitivity of the measurement was 0.81, specificity 0.95, predictive positive value 0.99, predictive negative value 0.45, and diagnostic accuracy 0.83. The test was positive in half the possible AD patients, and half those with miscellaneous memory disorders. It was negative in all anxious/depressed patients. Therefore, temporal lobe oriented CT might be a valuable tool for assessment of medial temporal lobe atrophy in AD routine practice.

Adult↗

PubMed1997

The unassisted respiratory rate/tidal volume ratio accurately predicts weaning outcome in postoperative patients.

OBJECTIVE: To evaluate the accuracies of the respiratory rate/tidal volume ratio (rate/volume ratio), minute volume, and negative inspired force in predicting weaning outcome in postoperative mechanically ventilated patients. DESIGN: A prospective, observational study. SETTING: Surgical intensive care unit of a 270-bed community teaching hospital. PATIENTS: One hundred eighty-three postoperative, mechanically ventilated patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The spontaneous minute volume, unassisted respiratory rate/tidal volume ratio, and negative inspired force were measured just before weaning. The rate/volume ratio was remeasured after 30 to 60 mins of weaning. Weaning was conducted by the patients' primary physicians. Weaning success was defined as unassisted breathing for >24 hrs. Predictive characteristics were computed using threshold values of 100 breaths/min/L, 10 L/min, and -20 cm H2O for the rate/volume ratios, minute volume, and negative inspired force, respectively. Receiver operating characteristic curves were also constructed to assess each parameter. Sensitivities for the initial rate/volume ratio, rate/volume ratio after 30 mins, minute volume, and negative inspired force were 0.97, 0.96, 0.76, and 0.96, respectively. Specificities were 0.33, 0.31, 0.40, and 0.07, respectively. Areas (+/- SD) for receiver operating characteristic curves were 0.76 +/- 0.08, 0.75 +/- 0.06, 0.54 +/- 0.08, and 0.62 +/- 0.07, respectively. The rate/volume ratio after 30 mins correlated with the initial rate/volume ratio; the rate/volume ratio after 30 mins did not add significant, additional predictive information. CONCLUSIONS: The rate/volume ratio measured at the beginning and after 30 mins of weaning is more highly predictive of weaning outcome than the negative inspired force and minute volume. The principal weakness of the rate/volume ratio is false-positive results.

APACHE↗

PubMed1997

Association between medial temporal lobe atrophy on CT and parietotemporal uptake decrease on SPECT in Alzheimer's disease.

OBJECTIVES: Alzheimer's disease is the most frequent cause of degenerative dementia. Despite the available diagnostic criteria, improvement of diagnosic accuracy is still required. The aim of this prospective study was to assess in a large population of patients referred to a memory clinic the diagnostic value of the combination of medial temporal lobe atrophy on temporal oriented CT and decreased temporoparietal uptake on HMPAO single photon emission tomography (SPECT). METHODS: The study was conducted in 125 patients aged 51-93: 64 with probable Alzheimer's disease (Mean (SD) mini mental state examination (MMSE)=18.34 (6.93)), duration of disease=6.48 (2.93) years, 13 possible Alzheimer's disease (MMSE=21.58 (5.48), duration of disease=6.08 (2.56)), 48 patients with miscellaneous memory disorders (MMSE=21.98 (6.10), duration the disease = 6.85 (3.91)). RESULTS: For the diagnosis of probable Alzheimer's disease, the sensitivity of this association was 0.56, the specificity 0.93, the positive predictive value 0.95, and the negative predictive value 0.45. The diagnosic accuracy was 0.68. Both medial temporal atrophy and parietotemporal decrease in uptake were present in four of 13 patients with possible Alzheimer's disease and 11 of 48 with miscellaneous memory disorders. The association was absent in 27 of 29 patients with frontotemporal dementia. In mild stages (MMSE>18; n = 32), the sensitivity of the association was 0.34, the specificity 0.93, the positive predictive value 0.85, and the negative predictive value 0.57. The diagnosic accuracy was 0.53. CONCLUSION: This association, although not sensitive, helps to select patients with high probability of Alzheimer's disease at an early stage which can be of interest for clinical and research purposes.

Aged↗