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Biomedical subjects

M Peters

Publications and source records attributed to M Peters.

At least 73 records · Page 4Linked to original sources
PubMed2002

A comparison of cerebral oxygenation as measured by the NIRO 300 and the INVOS 5100 Near-Infrared Spectrophotometers.

In this study cerebral oxygenation was measured using the NIRO 300 and the INVOS 5100 spectrophotometers in 10 healthy adult volunteers, exposed to varying degrees of hyperoxia and hypoxia. The results showed similar baseline values for tissue oxygenation index and regional cerebral oxygen saturation with mean (SD) values being 64.9% (5.1) and 62.3% (6.0), respectively. The overall bias was -2.1%, with the INVOS 5100 under-reading cerebral oxygenation compared to the NIRO 300, with limits of agreement of +/-14.7%. Both monitors demonstrated similar changes in response to hyperoxia and hypocapnia (coefficient of variance for FIo2 0.45 = 10.0%, FIo2 1.0 = 10.1%, hypocapnia = 14.5%). The reasons for the bias and variability may relate to differences in the methodological approaches of the two monitors. The correlation between the monitors in response to changes in cerebral oxygenation implies that they may be useful as trend monitors in clinical practice.

Adult↗
PubMed2002

International business travel: impact on families and travellers.

OBJECTIVES: Spouses and staff of the World Bank Group (WBG) were questioned about the impact of international business travel on families and travellers. Dependent variables were self reported stress, concern about the health of the traveller, and negative impact on the family. We hypothesised that several travel factors (independent variables) would be associated with these impacts. These travel factors had to do with the frequency, duration, and predictability of travel and its interference with family activities. METHODS: Survey forms were developed and distributed to all spouses of travelling staff as well as a small sample of operational staff. Kendall's tau b correlation coefficients of response frequencies were computed with the data from scaled items. Written responses to open ended questions were categorised. RESULTS: Response rates for spouses and staff were 24% and 36%, respectively. Half the spouse sample (n=533) and almost 75% of the staff sample (n=102) reported high or very high stress due to business travel. Self reported spouse stress was associated with six out of eight travel factors. Female spouses, those with children, and younger spouses reported greater stress. Self reported staff stress was significantly associated with four out of nine travel factors. Further insight into how business travel affects families and staff (including children's behavioural changes) and how families cope was gained through responses to written questions. CONCLUSIONS: The findings support the notion that lengthy and frequent travel and frequent changes in travel dates which affect family plans, all characteristic of WBG missions, negatively affects many spouses and children (particularly young children) and that the strain on families contributes significantly to the stress staff feel about their travel. Policies or management practices that take into consideration family activities and give staff greater leeway in controlling and refusing travel may help relieve stress.

Adaptation, Psychological↗
PubMed2002

Expression of N-acetyltransferases in periodontal granulation tissue.

Smoking is a major risk of periodontal diseases. At the site of first contact, the gingiva is exposed to aromatic amines and polycyclic hydrocarbons. These are metabolized by the N-acetyltransferases (NAT), leading to local detoxification and/or activation reactions contributing to the risk of periodontal destruction in smokers. The purpose of this study was to detect the expression of N-acetyltransferase isoenzymes NAT1 and NAT2 in periodontal granulation tissue. In 24 specimens obtained from periodontitis patients or control subjects, mRNA encoding for NAT1 and NAT2 was detected by RT-PCR, and proteins were identified by immunohistochemistry. In periodontal granulation tissues, immunoreactivity for NAT1 and NAT2 was detected in infiltrating leukocytes and fibroblasts. In normal gingiva, both enzymes were found in epithelial cells, whereas NAT1 was also detected in endothelial cells. The results suggest that these enzymes may play a role in the defense against xenobiotics and the accelerated progression of periodontal disease in smokers.

Acetyltransferases↗
PubMed2002

Sex-specific finger-length patterns linked to behavioral variables: consistency across various human populations.

In humans, as in nonhuman primates, the digits of the hands are similar in length during early fetal development. Subsequently, differentiation leads to a patter of unequal finger lengths, described by George as the finger-length pattern. Recent work by Manning and colleagues suggested that digit length patterns are due to early influences of sex hormones. Most importantly for psychology, such patterns might also relate to cognitive activities that are influenced by early organizing actions of sex hormones. The exciting possibility of having an easily measurable indicator of early action of sex hormones that relates to behavior led us to examine the universality of digit length patterns. With samples from Brazil, Canada, India, Turkey, and Korea, we showed that patterns of distal extent of finger tips are similar across different human populations. Consistent sex differences were found across the samples, showing that the index finger in males extends less far distally relative to the middle finger than is the case for females and that the difference in distal extent between index and ring fingers, relative to the middle finger, is smaller in females than in males.

Adult↗
PubMed2002

Influenza pandemic: preparedness planning in Germany.

The following conceptual framework formed the basis for a common decision made by the health ministers of Germany's 16 federal states to set up an influenza pandemic preparedness plan. The worst case scenario was used, on the basis of the data from the pandemic of 'Spanish flu', in 1918-20. The priority groups for vaccination were assessed, as well as the potentially available antiviral treatments. National policies could be highly improved by a common European view.

Disease Outbreaks↗
PubMed2001

Bovine neosporosis: immunoblot improves foetal serology.

The purpose of the study is the comparative evaluation of the immunofluorescent antibody test (IFAT) and an immunoblot (IB) test for the examination of foetal fluids for specific antibodies against Neospora caninum. Peritoneal and pleural fluids as well as abomasal contents were analysed. The results of the serological examinations were compared to those obtained by histological, immunohistochemical, and PCR analysis of foetal tissues as well as to the results of maternal serological examinations. Fluids were used undiluted in the IB and reactions against six immunodominant antigens were recorded. When the recognition of at least two immunodominant antigens was regarded as positive, the agreement of the IB with other diagnostic methods was good to moderate as characterised by kappa-values of 0.76 (histology/immunohistochemistry), 0.69 (maternal serology) and 0.54 (PCR on foetal tissues). The IB results agreed better with the results of the other diagnostic methods than those of the IFAT. The higher relative sensitivity of the IB was regarded as the main reason for the better agreement. However, also the specificity of the IB was superior to that of the IFAT in relation to histology/immunohistochemistry, maternal serology and PCR.

Abomasum↗
PubMed2001

Haploinsufficient Bmp4 ocular phenotypes include anterior segment dysgenesis with elevated intraocular pressure.

BACKGROUND: Glaucoma is a blinding disease usually associated with high intraocular pressure (IOP). In some families, abnormal anterior segment development contributes to glaucoma. The genes causing anterior segment dysgenesis and glaucoma in most of these families are not identified and the affected developmental processes are poorly understood. Bone morphogenetic proteins (BMPs) participate in various developmental processes. We tested the importance of Bmp4 gene dosage for ocular development and developmental glaucoma. RESULTS: Bmp4+/- mice have anterior segment abnormalities including malformed, absent or blocked trabecular meshwork and Schlemm's canal drainage structures. Mice with severe drainage structure abnormalities, over 80% or more of their angle's extent, have elevated IOP. The penetrance and severity of abnormalities is strongly influenced by genetic background, being most severe on the C57BL/6J background and absent on some other backgrounds. On the C57BL/6J background there is also persistence of the hyaloid vasculature, diminished numbers of inner retinal cells, and absence of the optic nerve. CONCLUSIONS: We demonstrate that heterozygous deficiency of BMP4 results in anterior segment dysgenesis and elevated IOP. The abnormalities are similar to those in human patients with developmental glaucoma. Thus, BMP4 is a strong candidate to contribute to Axenfeld-Rieger anomaly and other developmental conditions associated with human glaucoma. BMP4 also participates in posterior segment development and wild-type levels are usually critical for optic nerve development on the C57BL/6J background. Bmp4+/- mice are useful for studying various components of ocular development, and may allow identification of strain specific modifiers affecting a variety of ocular phenotypes.

Animals↗
PubMed2001

Economic analysis as a basis for large-scale nitrogen control decisions: reducing nitrogen loads to the Gulf of Mexico.

Economic analysis can be a guide to determining the level of actions taken to reduce nitrogen (N) losses and reduce environmental risk in a cost-effective manner while also allowing consideration of relative costs of controls to various groups. The biophysical science of N control, especially from nonpoint sources such as agriculture, is not certain. Widespread precise data do not exist for a river basin (or often even for a watershed) that couples management practices and other actions to reduce nonpoint N losses with specific delivery from the basin. The causal relationships are clouded by other factors influencing N flows, such as weather, temperature, and soil characteristics. Even when the science is certain, economic analysis has its own sets of uncertainties and simplifying economic assumptions. The economic analysis of the National Hypoxia Assessment provides an example of economic analysis based on less than complete scientific information that can still provide guidance to policy makers about the economic consequences of alternative approaches. One critical value to policy makers comes from bounding the economic magnitude of the consequences of alternative actions. Another value is the identification of impacts outside the sphere of initial concerns. Such analysis can successfully assess relative impacts of different degrees of control of N losses within the basin as well as outside the basin. It can demonstrate the extent to which costs of control of any one action increase with the intensity of application of control.

Agriculture↗
PubMed2001

Interleukin-6 expression in exo-focal neurons after striatal cerebral ischemia.

Although anatomical and biochemical properties of the rat entopeduncular nucleus (EPN) closely resemble those of the substantia nigra pars reticulata (SNr), the present study shows that, unlike in the SNr, focal cerebral ischemia does not cause trans-synaptic degeneration of EPN neurons, despite striatal infarction and a similar delayed glial activation in both nuclei. In this study, interleukin-6 (IL-6) expression was found within EPN neurons 3 and 7 days after striatal ischemia. Since it has been reported that neuroprotective properties seem to predominate IL-6 function and that distinct SNr regions which demonstrate low trans-synaptic neuronal degeneration show high IL-6 expression and vice versa, IL-6 expression within partially deafferentiated but surviving EPN neurons could represent an intrinsic neuroprotective mechanism.

Animals↗
PubMed2001

Hypertrophic pulmonary osteoarthropathy without clubbing of the digits.

Hypertrophic osteoarthropathy (HOA) typically occurs concurrently with clubbing of the digits, with isolated HOA being reported only rarely. We report two patients with intra-thoracic malignancy in whom HOA, demonstrated on bone scintigraphy, developed in the absence of clubbing. We also report the novel observation of involvement of the metatarsal and metacarpal bones by HOA.

Aged↗
PubMed2001

Lymphedema in a cohort of breast carcinoma survivors 20 years after diagnosis.

BACKGROUND: To the authors' knowledge, there are no long-term cohort studies of lymphedema, despite the substantial morbidity of arm swelling. The goal of this study was to identify prevalence of breast carcinoma-related lymphedema, time of onset, and associated predictive factors. METHODS: A cohort of 923 women consecutively treated with mastectomy and complete axillary dissection at our center between 1976 and 1978 was observed intensively for 20 years. Two hundred sixty-three study subjects (28.5%) who were alive and recurrence free constituted the cohort for the current study. A subset of 52 women (20% of study population) with contralateral mastectomy was analyzed separately. Subjects reported circumferential arm measurements taken using a validated instrument. In addition to providing analysis of clinical and treatment variables, this study is the first to the authors' knowledge to analyze possible etiologic factors in the posttreatment years, such as occupation, general physical activity, and sports/leisure activities. Univariate and multivariate analytic methods were used. RESULTS: At 20 years after treatment, 49% (128 of 263) reported the sensation of lymphedema. Arm swelling measurements were severe (> or = 2.0 in [5.08 cm]; patients reported measurement in inches) for 13% (33 of 263 women). Seventy-seven percent (98 of 128) noted onset within 3 years after the operation; the remaining percentage developed arm swelling at a rate of almost 1% per year. Of the 15 potential predictive factors analyzed, only 2 were statistically significantly associated with lymphedema: arm infection/injury and weight gain since operation (P < 0.001 and P = 0.02, respectively). CONCLUSIONS: This defined cohort, treated by axillary dissection 20 years ago, documents the high prevalence of lymphedema and its time course. Two significantly associated factors, both potentially controllable, are identified. The current study provides further support for treatments that limit lymph node dissection. The authors are prospectively evaluating patients undergoing sentinel lymph node biopsy.

Aged↗
PubMed2001

[One year of neonatal screening for sickle-cell disease in Emma Children's Hospital/Academic Medical Center in Amsterdam].

OBJECTIVE: Early detection of children with sickle cell disease, determination of carriership frequency as well as evaluation of the knowledge regarding this haemoglobinopathy in various ethnic risk groups. DESIGN: Prospective. METHODS: From 1 November 1998 through to 31 October 1999, the ethnic background was recorded for consecutive pregnant women under care of the Academic Medical Centre, Amsterdam, the Netherlands, and the presence of carriership for sickle cell disease was evaluated. Carriers were asked about their knowledge of sickle cell disease. A diagnostic blood test of cord blood was also performed using a PCR which could detect both haemoglobin S and C mutations. RESULTS: Fifty-five carriers were detected in a group of 1,016 investigated pregnant women (5.4%). The carriership frequencies in Surinam and African women were 12 and 15.7%, respectively. Knowledge of sickle cell disease, its occurrence in populations at risk, as well as the terms 'inheritance' and 'carriership', differed substantially between Surinam and African women, with awareness being lower in the latter group. In six cases informed consent was not asked. All other 49 carriers consented to a diagnostic test. Two intrauterine deaths occurred. Four children had sickle cell disease: three had HbSS, one had HbSC. Nineteen children proved to be carriers for sickle cell disease, 18 were heterozygotes for HbS, one for HbC. CONCLUSION: This targeted neonatal screening for sickle cell disease was feasible in a hospital setting. The number of children diagnosed with the disease supports the wider implementation of this method of early detection.

Africa↗
PubMed2001

Plasmid-encoded catalase KatA, the main catalase of Pseudomonas fluorescens strain Cb36.

The plasmid-state catalase gene katA of the phenol gradative Pseudomonas fluorescens isolate Cb36 has been characterized and shown to be the major catalase of this strain. The predicted amino acid sequence of KatA revealed significant similarity with the catalase sequence from Neisseria meningitidis and has probably the non-pseudomonad origin. The specific activity of catalase was investigated and elevated catalase activity was found in stationary phase cells. The consensus sequence for promoters recognized by the stationary phase sigma factor sigma(s) was found 212 bp upstream of the putative ATG start codon. The ability of KatA to detoxify a high concentration of hydrogen peroxide and protect Pseudomonas putida and Escherichia coli cells was shown.

Amino Acid Sequence↗
PubMed2001

Neospora caninum infection associated with stillbirths in captive antelopes (Tragelaphus imberbis).

Neosporosis was diagnosed in full-term stillborn twin calves of captive antelopes (Tragelaphus imberbis) in a German zoo. In both calves a multifocal non-suppurative encephalitis was present and infection with Neospora (N.) caninum was confirmed by foetal serology and PCR. N. caninum-DNA was detected in brain, heart, lung, liver and spleen of a third full-term stillborn calf. Histopathological lesions were absent in this calf and antibodies against N. caninum were not detected in pleural fluid. Immunohistochemistry failed to demonstrate N. caninum antigen in all three calves.

Animals↗
PubMed2001

Ischemic preconditioning prevents endothelial injury and systemic neutrophil activation during ischemia-reperfusion in humans in vivo.

BACKGROUND: Endothelial dysfunction leading to neutrophil infiltration of tissues has been implicated in tissue injury caused by ischemia-reperfusion (IR). Tissue injury during IR can be reduced by prior ischemic preconditioning (IPC). In humans, it is unclear whether endothelial dysfunction occurs during IR or whether IPC offers protection against endothelial dysfunction and inflammatory cell activation. We studied the effects of experimental IR on endothelial and neutrophil function in the human forearm in vivo and examined the protection afforded by IPC. METHOD AND RESULTS: The forearm was made ischemic for 20 minutes by inflating a blood pressure cuff to 200 mm Hg. We assessed endothelial function of conduit (radial artery flow-mediated dilation) and resistance vessels (blood flow responses to intra-arterial infusion of the endothelium-dependent dilator acetylcholine) in healthy volunteers before and after IR. IR reduced flow-mediated dilation of the radial artery at 15 minutes of reperfusion (7.7+/-1.5% to 3.5+/-0.9%) and the dilator response of resistance vessels to acetylcholine at 15, 30, and 60 minutes of reperfusion. IR did not reduce the dilator response of the radial artery to glyceryltrinitrate and only caused a small reduction of glyceryltrinitrate-induced dilation of resistance vessels at 60 minutes of reperfusion. IR caused an increase in neutrophil CD11b expression and platelet-neutrophil complexes in the circulating blood. IPC (three 5-minute episodes of ischemia) before IR prevented endothelial dysfunction and neutrophil activation. CONCLUSIONS: A clinically relevant period of ischemia-reperfusion causes profound and sustained endothelial dysfunction and systemic neutrophil activation. IPC attenuates both of these effects in humans.

Acetylcholine↗