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Biomedical subjects

B Mueller

Publications and source records attributed to B Mueller.

At least 19 recordsLinked to original sources
PubMed2003

Diagnosis of diabetic autonomic neuropathy: a multivariate approach.

AIM/HYPOTHESIS: In the diagnosis of diabetic autonomic neuropathy (DAN) various autonomic tests are used. We took a novel statistical approach to find a combination of autonomic tests that best separates normal controls from patients with DAN. METHODS: Twenty-four patients with Type-1 diabetes mellitus considered as having mild to moderate DAN as well as 10 normal, nondiabetic control subjects were analysed, searching for a test or a combination of tests that would optimally discriminate Type-1 diabetes mellitus from controls. Variations of heart rate during deep breathing (deltaR6) and during a Valsalva manoeuvre (VR), the number of reactive sweat glands on the foot (testing sympathetic sudomotor function), and the response of human pancreatic polypeptide to hypoglycaemia [ln(deltahPP+1)] were evaluated. RESULTS: Respective values for respective sensitivity and specificity values were: deltaR6, 96 and 70%; VR, 96 and 60%; sweat gland function, 71 and 90%; and ln(deltahPP+1), 71 and 90%. In a multivariate analysis approach a single discriminant function separating patients with Type-1 diabetes mellitus from nondiabetic controls was generated [Logit P=288.5-[14.7 deltaR6]-[26.6 ln(deltahPP+1)]]. This function allowed complete separation of patients with Type-1 diabetes mellitus from normal controls. CONCLUSION/INTERPRETATION: We conclude that the combined determination of deltaR6 and of ln (deltahPP+1) optimally separates subjects with parasympathetic impairment from normal subjects. In addition, this combination of tests may serve as a sensitive method for the assessment of DAN.

Adult↗
PubMed2003

Chemical and antimicrobial properties of calcium hydroxide mixed with irrigating solutions.

AIM: Chemical and antimicrobial effects of paste-like suspensions of calcium hydroxide (Ca(OH)2) powder with chlorhexidine (CHx), sodium hypochlorite (NaOCl) or iodine potassium iodide (IPI) solutions were tested and compared to conventional Ca(OH)2/saline paste. METHODOLOGY: Equivalent mixtures of Ca(OH)2 with irrigating solutions were compared to conventional Ca(OH)2/saline paste for their ability to raise the pH in root dentine. Ca(OH)2 pastes were compacted into prepared root canals of single-rooted extracted human teeth. Changes in root pH over time were recorded with a microelectrode placed in standardized wells within root surfaces. Antimicrobial efficacy of test solutions and pastes against Enterococcus faecalis and Candida albicans was assayed using an agar diffusion test. RESULTS: The ability of Ca(OH)2 to raise the pH in the root dentine was maintained when using mixtures of Ca(OH)2 with CHx, NaOCl or IPI (Kruskal-Wallis, P > 0.05). Mixtures of Ca(OH)2 with the test solutions had similar antimicrobial properties as equivalent mixtures with saline (anova, P > 0.05). The efficacy of CHx was reduced when mixed with Ca(OH)2. No additive antiseptic effects were recorded between Ca(OH)2 and IPI or Ca(OH)2 and NaOCl. CONCLUSIONS: Ca(OH)2 is a strong alkali, whose pH is not changed when adding weak acids or alkalis in aqueous suspensions. Under the conditions of this study, mixing Ca(OH)2 powder with the test irrigating solutions did not provide an increased antimicrobial effect compared to a conventional Ca(OH)2/saline medication.

Analysis of Variance↗
PubMed2001

Longitudinal electroproduction of charged pions from (1)H, (2)H, and (3)He.

Separated longitudinal and transverse cross sections for charged pion electroproduction from (1)H, (2)H, and (3)He were measured at Q(2) = 0.4 (GeV/c)(2) for two values of the invariant mass, W = 1.15 GeV and W = 1.60 GeV, in a search for a mass dependence which would signal the effect of nuclear pions. This is the first such study that includes recoil momenta significantly above the Fermi surface. The longitudinal cross section, if dominated by the pion-pole process, should be sensitive to nuclear pion currents. Comparisons of the longitudinal cross section target ratios to a quasifree calculation reveal a significant suppression in (3)He at W = 1.60 GeV. The W = 1.15 GeV results are consistent with simple estimates of the effect of nuclear pion currents, but are also consistent with pure quasifree production.

Journal Article↗
PubMed2001

Measurement of the charged pion electromagnetic form factor.

Separated longitudinal and transverse structure functions for the reaction 1H(e,e(')pi(+))n were measured in the momentum transfer region Q2 = 0.6--1.6 (GeV/c)(2) at a value of the invariant mass W = 1.95 GeV. New values for the pion charge form factor were extracted from the longitudinal cross section by using a recently developed Regge model. The results indicate that the pion form factor in this region is larger than previously assumed and is consistent with a monopole parametrization fitted to very low Q2 elastic data.

Journal Article↗
PubMed2001

Human leukocyte antigen G up-regulation in lung cancer associates with high-grade histology, human leukocyte antigen class I loss and interleukin-10 production.

Immune evasion in lung cancer results from both structural and functional alterations of human leukocyte antigen (HLA) class I molecules and the local release of immunosuppressive cytokines. Recent data suggest that HLA-G, a nonclassical class Ib molecule, is involved in immune evasion by tumor cells. We sought to determine whether HLA-G could contribute to immunescape in lung cancer. All of 19 tumor specimens examined demonstrated detectable membrane-bound (HLA-G1), as well as soluble (HLA-G5) isoform transcription. Nine of 34 (26%) tumors were positive by immunohistochemistry using monoclonal antibody (mAb) 4H84, recognizing all denatured HLA-G isoforms, of which six were positive using mAb 16G1, recognizing soluble HLA-G. HLA-G immunoreactivity correlated with high-grade histology, with HLA-G being preferentially expressed on large-cell carcinomas. In these patients, loss of classical HLA class I molecules was observed to associate with HLA-G protein up-regulation. Moreover, we found interleukin-10 expressed in 15 of 34 (44%) tumors, and in most of the HLA-G-positive cases (7 of 9), suggesting up-modulation of HLA-G by interleukin-10. It is conceivable that HLA-G expression in lung cancer might be one of the ways how the tumor down-regulates host immune response, in addition to interleukin-10 production and HLA class I loss.

Aged↗
PubMed2001

Parental occupations and childhood brain tumors: results of an international case-control study.

OBJECTIVE: To evaluate the role of parental occupations in the etiology of childhood brain tumors (CBT). METHODS: Population-based case-control studies were conducted concurrently in seven countries under the coordination of the International Agency for Research on Cancer, gathering 1,218 cases and 2,223 controls. We report here the findings related to parental occupations during the 5-year period before the child's birth. Risk estimates related to a number of paternal and maternal occupations were obtained by unconditional logistic regression adjusted for age, sex, year of birth, and center, for all types of CBT combined and for the subgroups of astroglial, primitive neuroectodermal tumors (PNET), and other glial tumors. RESULTS: An increased risk in relation with agricultural work was seen for all CBT combined and for other glial tumors. Increased risks for all tumors and PNET were seen for paternal occupation as an electrician; the same pattern held for maternal occupation when children under 5 were selected. Paternal occupation as a driver or mechanic, and maternal work in an environment related to motor-vehicles were associated with an increased risk for all CBT and astroglial tumors. More case mothers compared to control mothers were employed in the textile industry. CONCLUSION: Our study reinforces previous findings relative to the role of parental work in agriculture, electricity, or motor-vehicle related occupations and maternal work in the textile industry. It does not confirm previous associations with work environments including aerospace, the chemical industry, or the food industry, or with maternal occupation as a hairdresser, a nurse, or a sewing machinist, and paternal occupation as a welder.

Adolescent↗
PubMed2001

Marrow transplants from unrelated donors for patients with aplastic anemia: minimum effective dose of total body irradiation.

Patients with aplastic anemia who do not have suitably HLA-matched, related donors generally receive immunosuppressive treatment as first-line therapy and are considered for transplantation from an unrelated donor only if they fail to respond to immunosuppressive treatment. In this setting, rates of transplantation-related morbidity and mortality have been high. We conducted a prospective study to determine the minimal dose of total body irradiation (TBI) sufficient to achieve sustained engraftment when it is used in combination with 3 cycles of 30 mg/kg of antithymocyte globulin (ATG) and 4 cycles of 50 mg/kg of cyclophosphamide (CY). We also wanted to determine the tolerability and toxicity of the regimen. The starting dosage of TBI was 3 x 200 cGy given over 2 days following CY/ATG. The TBI dose was to be escalated in increments of 200 cGy if graft failure occurred in the absence of prohibitive toxicity, and de-escalated for toxicity in the absence of graft failure. Twenty-one female and 29 male patients aged 1.3 to 46.5 years (median age, 14.4 years) underwent transplantation at 14 medical centers. The time interval from diagnosis to transplantation was 2.8 to 264 months (median, 14.5 months). All patients had been transfused multiple times and all had received 1 to 11 courses (median, 4 courses) of immunosuppressive treatment and other modalities of treatment. In 38 cases, the donors were HLA-A, -B and -DR phenotypically matched with the patients, and, in 12 cases, the donor phenotype differed from that of the recipient by 1 HLA antigen. Recipients of mismatched transplants were considered separately for TBI dose modification, and this study is still ongoing. Seven patients did not tolerate ATG and were prepared with 6 x 200 cGy of TBI plus 120 mg/kg of CY. Of the HLA-matched recipients prepared with CY/ATG/TBI, all 20 who received 3 x 200 or 2 x 200 cGy of TBI achieved engraftment, and 10 are alive. Of the 13 patients who received 1 x 200 cGy of TBI, 1 failed to engraft, and 8 are alive. Each of 10 patients who received an HLA-nonidentical transplant achieved engraftment, and 3 of 6 who were given 3 x 200 cGy of TBI, and 4 of 4 who were given 2 x 200 cGy are alive. Pulmonary toxicity occurred in 8 of 30 patients who were given 3 x 200 or 2 x 200 cGy of TBI concurrently with ATG and CY at 200 mg/kg, and in 2 of 13 patients who received 1 x 200 cGy of TBI, a pattern that suggests a decrease in toxicity with TBI dose de-escalation. Overall, the highest probability of survival (73%) was observed among patients who underwent transplantation within 1 year of diagnosis, compared with patients who underwent transplantation after a longer period of disease. In addition, younger patients (aged < or = 20 years) were more likely to survive than older patients (aged > 20 years). Thus, for patients with an HLA-matched, unrelated donor, a TBI dose of 200 cGy (in combination with CY/ATG) was sufficient to allow for engraftment without inducing prohibitive toxicity. As in previous studies, patient age and pretransplantation disease duration remain important prognostic factors.

Adolescent↗
PubMed2001

An outbreak of viral gastroenteritis in a mother-and-child health clinic.

An outbreak of diarrhoeal disease in a modern mother-and-child health clinic prompted the health authorities to initiate a retrospective cohort study in order to assess the scope of the outbreak and to identify possible risk factors. The management of the clinic had been rather concerned because four similar outbreaks had occurred during the last two years. A total of 151 guests, i.e. mothers with their children, who had arrived some days before the peak of the outbreak for a three-week-stay and another 15 guests who had arrived earlier and had extended their stay were enrolled in the study which mainly focused on the possible role of treatment measures as risk factors. In addition, a total of 49 staff members were requested to provide information about symptoms, working area and attendance at work. Relevant data were available from 164 of 166 guests and 47 of 49 staff members (response rates 98.8% and 96.0%, respectively). The attack rate among guests was 44.0% (adults 27.0%, children 54.0%) and among staff 23.4%. The mean age of affected children (3.5 years) was significantly lower than that of those not affected (6.3 years). The main symptoms were diarrhoea and vomiting. The sudden start of the outbreak suggested a single source of infection which, however, remained unknown. Person-to-person transmission was supposed to be the cause of the following spread. No association between distinct treatment measures and the disease was proven by the cohort study. Norwalk-like viruses as well as astroviruses were detected by polymerase chain reaction in specimens taken from seven patients. No other enteropathogenic agents were found. Regarding the special conditions in a mother-and-child health clinic where social contacts among guests are much more frequent and intensive than among patients in a "normal" hospital, measures to prevent the spread of gastrointestinal infections should concentrate on early recognition and isolation of symptomatic individuals. Guests and staff members should be instructed to keep to the rules of personal hygiene, especially handwashing. If disinfection is required, it should be virucidal.

Adolescent↗
PubMed2001

Psychophysiological responses in ADHD boys with and without conduct disorder: implications for adult antisocial behavior.

OBJECTIVE: Several studies have demonstrated that the presence of attention-deficit/hyperactivity disorder (ADHD) in childhood increases the risk of antisocial behavior developing in adulthood. However, because previous research did not consider comorbid conduct disorder (CD), the question of whether ADHD by itself or only the association of ADHD with CD implies a risk of adult antisocial behavior developing is still under discussion. METHOD: Because several characteristics of psychophysiological response had been shown to be associated with future increased likelihood of adult antisocial behavior, autonomic arousal as well as electrodermal responses to orienting and aversive stimuli were assessed in 26 boys with ADHD+CD compared with 21 boys with ADHD alone and 21 controls. RESULTS: Boys with a comorbid condition of ADHD+CD showed a decrement of autonomic responses and a more rapid habituation to orienting and aversive startling stimuli compared with age-matched children with ADHD alone. CONCLUSIONS: Boys with ADHD+CD show a psychophysiological response pattern that is very similar to that reported in antisocial personalities. These findings give further support for a high persistence of antisocial behavior from childhood to adulthood, while no evidence was found that ADHD itself is associated with a predisposition to antisocial behavior.

Adolescent↗
PubMed2001

Thalidomide in gastrointestinal disorders.

Thalidomide was originally marketed as a sedative, but was removed from the market in 1961 after it was associated with an epidemic of severe birth defects. Subsequently, it has been shown to have therapeutic efficacy in a number of the gastrointestinal tract conditions characterised by immune dysregulation. The exact mechanism of the immunosuppressive effects of thalidomide is unknown; proposed mechanisms include inhibition of tumour necrosis factor alpha release and inhibition of angiogenesis. In chronic graft versus host disease, use of high dose thalidomide (1200 mg/day) may bring about a response in 20% of patients with refractory disease. Thalidomide 200 mg/day helps eradicate ulcers in 50% of patients with HIV-associated oral aphthous ulceration. In Behçet's disease, thalidomide 100 to 300 mg/day can decrease the number of mucocutaneous ulcers, although full remission occurs in less than 20% of patients. In Crohn's disease, thalidomide 50 to 300 mg/day may decrease the severity of mucosal disease and prompt closure of fistulae. Patients to be placed on thalidomide therapy must practice either abstinence or strict birth control; women must undergo regular pregnancy testing and utilise 2 forms of contraception. Other adverse effects include sedation (present in nearly all patients), symptomatic neuropathy (present in approximately 20%), and skin rashes. Given the potential toxicity, thalidomide use should generally be limited to clinical protocols with institutional review board oversight.

Behcet Syndrome↗
PubMed2000

Strange magnetism and the anapole structure of the proton.

The violation of mirror symmetry in the weak force provides a powerful tool to study the internal structure of the proton. Experimental results have been obtained that address the role of strange quarks in generating nuclear magnetism. The measurement reported here provides an unambiguous constraint on strange quark contributions to the proton's magnetic moment through the electron-proton weak interaction. We also report evidence for the existence of a parity-violating electromagnetic effect known as the anapole moment of the proton. The proton's anapole moment is not yet well understood theoretically, but it could have important implications for precision weak interaction studies in atomic systems such as cesium.

Journal Article↗
PubMed2000

[What you always wanted to know about HbA1c].

Irreversible, nonenzymatic glycation of the haemoglobin A beta chain leads to the formation of haemoglobin A1c (HbA1c), a stable minor haemoglobin component with enhanced electrophoretic mobility. The rate of formation of HbA1c is directly proportional to the ambient glucose concentration. HbA1c is commonly used to assess long-term blood glucose control in patients with diabetes mellitus, because the HbA1c value has been shown to predict the risk for the development of many of the chronic complications in diabetes. There are currently four principal glycohaemoglobin assay techniques (ion-exchange chromatography, electrophoresis, affinity chromatography and immunoassays) and over 20 methods that measure different glycated products. The ranges indicating good and poor glycaemic control can vary markedly between different assays. At the moment values differ between methodologies and even between different laboratories using the same methodology. Optimal use of HbA1c testing requires standardisation. There is progress towards international standardisation and improved precision of HbA1c which will lead to all assays reporting results in a standardised way. Clinicians ordering HbA1c testing for their patients should be aware of the type of assay method used, the reference interval, potential assay interferences (e.g. haemoglobinopathies, chronic alcohol ingestion, carbamylation products in uraemia) and assay performance. And they should know that a variety of factors have been shown to directly influence HbA1c values, e.g. iron deficiency anaemia, chronic renal failure and shortened red blood cell life span.

Anemia, Iron-Deficiency↗
PubMed2000

Interaction within clusters of dendritic cells and helper T cells during initial Th1/Th2 commitment.

Cytokines are the main agents known to regulate Th1 / Th2 commitment, where they may operate through paracrine activity within clusters of T cells gathered around dendritic cells (DC). An in vitro system is used here to test this possibility, using clusters around DC composed of naive TCR-transgenic ovalbumin peptide 323 - 339-specific CD4(+) T cells as targets plus TCR-transgenic pigeon cytochrome C peptide 88 - 104-specific CD4(+) polarized Th1 or Th2 cells as inducers. The polarized inducer cells exerted their maximum effect when the two T cell populations were activated within the same cluster, implemented by allowing a single DC to present both their epitopes. This finding thus supports the paracrine hypothesis. The system was then employed to explore the role of individual cytokines by means of inhibition by monoclonal antibodies. Development of Th2 commitment proved strictly dependent on the IL-4 produced by the Th2 inducers. For Th1 commitment, IFN-gamma and IL-12 were both needed, but with IFN-gamma required only during the initial period of culture. The rapid timing observed under these conditions places constraints on the molecular basis of commitment, and appears accurately to reflect the physiological response in vivo.

Animals↗
PubMed2000

Chondral lesions after arthroscopic meniscus repair using meniscus arrows.

Meniscus repair using bioabsorbable devices has become popular in the last few years. Good clinical results have been reported and few complications have been published. This report describes the case of a 37-year-old male patient with a lateral meniscus repair using 4 Meniscus Arrows (Bionx Implants, Blue Bell, PA). Postoperatively, repeated episodes of intra-articular effusions have occurred. A second-look arthroscopy 8 months after the reconstruction showed that the meniscus tear had not healed and revealed the presence of chondral damage corresponding to the location of the arrows in the posterior area of the lateral femoral condyle. Surgeons using the Meniscus Arrow should be aware of this possible postoperative complication.

Absorbable Implants↗
PubMed2000

Angiogenesis in cutaneous lymphoproliferative disorders: microvessel density discriminates between cutaneous B-cell lymphomas and B-cell pseudolymphomas.

The role of angiogenesis in neoplastic disorders is supported by the evidence that tumor growth beyond a certain size requires induction of new blood vessels. The extent of tumor-associated angiogenesis, measured as microvessel density (MVD), has shown to correlate with aggressiveness and the prognostic outcome in several malignant neoplasms. Few data have been reported on the angiogenic response in lymphoproliferative diseases. In this study, the MVD has been assessed in benign and malignant primary cutaneous B-cell lymphoproliferative disorders. MVD was determined in formaldehyde-fixed, paraffin-embedded specimens of primary cutaneous B-cell lymphomas (CBCL; n = 18) and cutaneous B-cell pseudolymphomas (B-PSL; n = 22) according to previously described protocols but was performed using computer-aided microscopic morphometry. The endothelial cells of microvessels were identified by immunohistochemical staining for factor VIII-related antigen and CD31. The MVD was 99 dots/mm2 for CBCL and 68 dots/mm2 for PSL, and a MVD of 115 dots/mm2 for CBCL and 73 dots/mm2 for PSL by using an antibody against factor VIII-related antigen and CD31 antigen, respectively. Univariate analysis revealed statistically highly significant differences in MVD between CBCL and B-PSL (P = 0.0036 with staining for factor VIII-related antigen and P = 0.0002 with staining for CD31 antigen). This study analyzes for the first time the angiogenic response in CBCL compared with that of B-PSL and demonstrates that MVD discriminates between CBCL and B-PSL. However, because of an overlap in the ranges of MVD in CBCL and PSL, the MVD is not useful as a diagnostic tool in individual cases.

Blood Vessels↗