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Biomedical subjects

M Baumann

Publications and source records attributed to M Baumann.

At least 271 records · Page 15Linked to original sources
PubMed1988

The alpha adrenergic binding properties of terazosin in the human prostate adenoma and canine brain.

Clinical trials are currently underway to evaluate the efficacy of terazosin for the treatment of symptomatic benign prostatic hyperplasia (BPH). Terazosin is a potent and selective alpha 1 adrenergic blocking agent structurally similar to prazosin. The alpha adrenergic binding properties of terazosin were studied in human prostate adenomas and canine brains using radioligand receptor binding methods. Saturation analyses were performed at varying concentrations of [125I]-Heat and [3H]rauwolscine [( 3H]Ra) in human prostate adenomas and canine brains. The binding of [125I]-Heat and [3H]Ra in the human prostates and canine brains was consistently saturable and of high affinity. The equilibrium dissociation constant (Kd) for [125I]-Heat binding in the canine brains and human prostate adenomas was 84.4 +/- 4.3 pM and 65.4 +/- 19.2 pM, respectively (p greater than 0.05). The (Kd) for [3H]Ra binding in the human prostate adenomas and canine brains was 1.21 +/- 0.23 nM and 1.52 +/- 0.28 nM, respectively (p greater than 0.05). The density of alpha 1 (0.37 +/- 0.15 fmol/mg. wet wt.) and alpha 2 (0.29 +/- 0.09 fmol/mg. wet wt. adrenergic binding sites in the human adenomas were similar (p greater than 0.05). The IC50 corrected (IC50 corr) of terazosin for [125I]-Heat and [3H]Ra binding sites in the human prostate was 2.5 nM and 1.0 micron., respectively. The IC50 corr of terazosin for [125I]-Heat and [3H]Ra binding sites in the canine brain was 2.0 nM and 0.8 microM, respectively. The competitive binding assays indicate that terazosin binds selectively to alpha 1 adrenergic binding sites in the human prostate and canine brain.

Adrenergic alpha-Antagonists↗
PubMed1988

The effect of electrocautery on neurotransmitter receptor binding assays in the canine prostate.

The purpose of this study was to determine whether resection of the prostate with electrocautery alters the binding properties of various neurotransmitter ligands. Prostate glands were removed from four adult male dogs. The prostates were divided in the midsaggital plane and one half of the prostate was resected using a resectoscope. Saturation experiments were performed on the resected and control prostatic tissue using 3H-NMS, 125I-Heat, and 3H-rauwolscine. The mean equilibrium dissociation constants (Kd) and the mean densities of 3H-NMS, 125I-Heat, and 3H-Rauwolscine binding sites were similar in tissue homogenates obtained from control and resected portions of the prostate (p greater than 0.05). Resection of the prostate using electrocautery did not alter the binding properties of various neurotransmitter ligands for characterizing and quantifying muscarinic cholinergic, alpha 1 adrenergic, and alpha 2 adrenergic binding sites in the canine prostate. Approximately 90% of prostatectomies for symptomatic BPH (benign prostatic hyperplasia) are performed transurethrally. The ability to accurately measure neurotransmitter receptor densities in prostate tissues obtained following transurethral resection is imperative for our future studies designed to elucidate the role of alpha adrenergic receptors in the development of bladder outlet obstruction in men with BPH.

Animals↗
PubMed1988

Tuberculosis, tuberculin reactivity, and delayed cutaneous hypersensitivity in nursing home residents.

When all residents of a 460-bed nursing home were tuberculin tested after discovery of a fatal case of pulmonary tuberculosis, 34% reacted, including 6% who gave boosted reactions. Twenty-four of 262 (9.2%) nonreactors converted to tuberculin reactors 6 months after exposure. Six of the convertors were among the 21% of the residents who were originally considered anergic on the basis of negative Candida and Trichophyton skin tests. These results confirm the observation that aged nursing home residents have lower rates of tuberculin reactivity than earlier in their lives, and that tuberculosis is a nosocomial infection in nursing homes. However, generalized immune senescence cannot be invoked as a reason for apparent susceptibility because the very marker of infection--the development of tuberculin reaction--is evidence of some degree of immune competence. Furthermore, the presence of cutaneous anergy as clinically determined does not predict inability to develop an immune response to the tubercle bacillus.

Aged↗
PubMed1988

The stereospecificity of LY253352 for alpha 1-adrenoceptor binding sites in the brain and prostate.

1. The stereospecificity of the enantiomers of LY253352, a potent and selective alpha 1-adrenoceptor antagonist, were studied in the human prostate and canine brain using radioligand receptor binding methods. 2. The mean equilibrium dissociation constant (KD) in the canine brain and human prostatic adenoma was 84.4 pM and 65.4 pM, respectively. 3. The alpha 1-adrenoceptor density in the canine brain was approximately eight fold greater than in the human prostatic adenoma. 4. The mean Ki values of (-)-LY253352 and (+)-LY253352 in the prostate were 0.19 nM and 5.79 nM, respectively. 5. The mean Ki values of (-)-LY253352 and (+)-LY253352 in the brain were 0.29 nM and 34.7 nM, respectively. 6. This study indicates that the stereochemical specificity of the optical isomers of LY253352 is a manifestation of differential affinities of the enantiomers for alpha 1-adrenoceptor binding sites. 7. The differential affinities of (+)-LY253352 in the brain and prostate are suggestive of subtle unique properties of adrenoceptor binding sites in these tissues.

Animals↗
PubMed1988

Activities of phosphohexose isomerase and other glycolytic enzymes in normal and tumor tissue of patients with neoplastic diseases: comparison with serum activities and correlation to tumor staging and grading.

Of five glycolytic enzymes tested, only the serum activity of phosphohexose isomerase (PHI) was elevated in the vast majority of 140 patients with gastrointestinal, kidney or mammary carcinomas. However, in the tumor tissues all enzymes were increased to about the same extent. Thus, the measured increase in the serum activity of PHI is not due to a specific overproduction in the malignant cells. A general rise in the glycolytic enzyme activities in the malignant tissue could be detected already in early stages without metastases and in well-differentiated tumors.

Fructose-Bisphosphate Aldolase↗
PubMed1988

Significance of serum phosphohexose isomerase in gastrointestinal cancer at different stages.

The purpose of this study was to reevaluate the significance of serum PHI in gastrointestinal cancer at histopathologically defined stages prior to primary treatment. A total of 248 patients with malignant tumors of the gastrointestinal tract and a collective of 42 patients with noncancerous diseases were studied. The results are compared with those obtained with the established markers tissue polypeptide antigen (TPA) and carcinoembryonic antigen (CEA). Phosphohexose isomerase (PHI) revealed an overall diagnostic sensitivity of 69%, combined with a specificity of 74%. The corresponding data for TPA were found to be 73 and 47% while for CEA 26 and 95% respectively were determined. Even in the early stages of colorectal and esophageal carcinoma, PHI showed a sensitivity of about 60%. A continuous rise of PHI serum levels, correlating well with the extent of the tumor disease, could be detected. In contrast to TPA and CEA, PHI assay can be carried out with a minimum of laboratory efforts, in a short time and at low costs. These findings suggest that serum PHI assay is a useful aid for screening of gastrointestinal cancer, especially esophageal and gastric carcinoma, and a reliable marker for treatment control and follow-up.

Antigens, Neoplasm↗
PubMed1988

Laboratory assessment of terazosin and alpha-1 blockade in prostatic hyperplasia.

The alpha-1 adrenergic innervation of the human prostate has been studied using radioligand receptor binding methods and in vitro contractile experiments. The density of alpha-1 adrenergic binding sites is of the same order of magnitude as alpha-2 adrenergic and muscarinic-cholinergic (MCh) receptors in the human prostate adenoma. The contractile response of human prostate adenomas to selective alpha-1, alpha-2, and MCh agonists indicated that smooth muscle contraction of the human prostate is mediated by alpha-1 adrenoceptors. The selective affinities of terazosin for alpha-1 and alpha-2 binding sites were determined using competitive displacement assays. Terazosin was shown to have a four hundred-fold greater affinity for alpha-1 binding sites. The concentration of terazosin-inhibiting phenylephrine-induced contractions suggested that terazosin inhibits prostate smooth muscle contraction via alpha-1 adrenoceptors.

Adrenergic alpha-Antagonists↗
PubMed1988

The effect of human recombinant GM-CSF on the myelopoiesis in a long-term bone marrow culture (LTBMC).

The long-term bone marrow culture (LTBMC) allows continuous self-renewal of a myeloid precursor population from an adherent stromal cell layer. We investigated the effect of human recombinant GM-CSF (100 ng/ml) on the in vitro hemopoiesis in a LTBMC. After a culture period of 14 days we observed a 2.3-fold increase in the total number of non-adherent cells in the cultures containing GM-CSF. Whereas the total cell number in the cultures without GM-CSF decreased after 28 days, proliferation continued in the cultures with GM-CSF. During the first 14 days there was a slight decrease of the number of CFU-GM in the cultures with GM-CSF. Thereafter no significant difference in the numbers of committed progenitors present in two culture systems could be observed.

Bone Marrow Cells↗
PubMed1988

[Maternity and extreme poverty. Ways of supervising pregnancy and delivery].

In women living under extreme poverty conditions, isolation, absence of social support, stress, seem to play a major role in the morbidity of pregnancy. In spite of thorough monitoring and frequent hospitalization, morbidity remains. This study stresses that the follow-up of pregnancies should not only be characterized by a quantitatively increased medical monitoring, but also by a warmer relationship between women living in a disadvantaged environment and health personnel.

Adolescent↗
PubMed1988

[Effect of intraoperative local polyvinylpyrrolidone iodine administration on the risk of wound infection following appendectomy].

A study conducted into 91 appendectomised patients revealed wound infection rates to worsen from eight to 26 per cent (p less than 0.05) in the wake of locally delimited intra-operative application of povidone-iodine solution, two per cent in concentration. No other factors were found to be responsible for that aggravation. Tissue toxicity was found to outweight bactericidal effects, even with application in diluted and PVP-bonded form. Hence, povidone-iodine solutions not even in diluted form should ever be applied to wound treatment.

Adult↗
PubMed1987

Apolipoprotein A-I-binding protein from human term placenta. Purification and partial characterization.

A protein that binds to the main apoprotein, apoA-I, of human high density lipoprotein (HDL) has been isolated from human placenta. Ligand blotting after SDS gel electrophoresis indicated that the 120 kDa protein in the absence of reducing agents binds apoA-I. If gel electrophoresis was performed under reducing conditions two main bands, approx. 50 and 30 kDa that did not bind apoA-I, were evident. In an enzyme-linked immunosorbent assay the binding protein specifically bound apoA-I, delipidated or as HDL. ApoA-II, apo E and LDL did not compete with apoA-I for binding to this protein.

Apolipoprotein A-I↗
PubMed1987

Identification and characterization of alpha 1 adrenergic receptors in the canine prostate using [125I]-Heat.

We have recently utilized radioligand receptor binding methods to characterize muscarinic cholinergic and alpha adrenergic receptors in human prostate adenomas. The primary advantages of radioligand receptor binding methods are that neurotransmitter receptor density is quantitated, the affinity of unlabelled drugs for receptor sites is determined, and receptors can be localized using autoradiography on slide-mounted tissue sections. Recently, [125I]-Heat, a selective and high affinity ligand with high specific activity (2200 Ci/mmole) has been used to characterize alpha 1 adrenergic receptors in the brain. In this study alpha 1 adrenergic receptors in the dog prostate were characterized using [125I]-Heat. The Scatchard plots were linear indicating homogeneity of [125I]-Heat binding sites. The mean alpha 1 adrenergic receptor density determined from these Scatchard plots was 0.61 +/- 0.07 fmol/mg. wet wt. +/- S.E.M. The binding of [125I]-Heat to canine prostate alpha 1 adrenergic binding sites was of high affinity (Kd = 86 +/- 19 pM). Steady state conditions were reached following an incubation interval of 30 minutes and specific binding and tissue concentration were linear within the range of tissue concentrations assayed. The specificity of [125I]-Heat for alpha 1 adrenergic binding sites was confirmed by competitive displacement assays using unlabelled clonidine and prazosin. Retrospective analysis of the saturation experiments demonstrated that Bmax can be accurately calculated by determining specific [125I]-Heat binding at a single ligand concentration. [125I]-Heat is an ideal ligand for studying alpha 1 adrenergic receptors in the prostate and its favorable properties should facilitate the autoradiographic localization of alpha 1 adrenergic receptors in the prostate.

Animals↗
PubMed1986

The Ca++ permeability of the apical membrane in neuromast hair cells.

The mechanosensitivity of eel (Anguilla anguilla) neuromasts was measured by the impulse responses of single afferent nerve fibers to mechanical stimuli. It is dependent on the potential across the skin and on the ions in the water outside the apical membrane of the sensory cells. The mechanosensitivity decreases to zero when the skin is polarized by 10-100 mV cathodal DC (skin surface negative); it increases with increasing (10-60 mV) anodal DC and remains remarkably constant with higher polarization (Fig. 1). The mechanosensitivity increases with increasing concentrations of Ca++ outside the apical membrane of the sensory cells. Na+ and K+ have no influence. Addition of La , Co++, Mg++, D 600 and A-QA 39 inhibits the mechanosensitivity; the degree of inhibition varies with the inhibitor and the ratio [Ca++]/[inhibitor], indicating that the inhibition is competitive (Figs. 2, 3). We conclude that the apical membrane is specifically permeable to Ca++ ('late Ca channel') and that the inward receptor current through the apical membrane is carried by Ca++. Streptomycin also inhibits mechanosensitivity by competing with Ca++. With streptomycin, however, anodal polarization reduces, rather than increases, the mechanosensitivity (Fig. 4).(ABSTRACT TRUNCATED AT 250 WORDS)

Anguilla↗
PubMed1986

Cardiovascular risk factors and hemorheology. Physical fitness, stress and obesity.

To date there is little information about hemorheological data in the presence of secondary risk factors. Inter- and intraindividual comparisons of hemorheological parameters show that fitness has a significant influence on blood fluidity as quantified by ex vivo measurements of blood and plasma viscosity, red cell filterability and red cell aggregation. In fitter individuals blood is more fluid. Similar observations can be made with stress. Prolonged psychoemotional stress leads to a loss in blood fluidity and red cell filterability. Finally a comparison between excessively obese patients and healthy controls reveals a deterioration in hemorheological parameters in the obese group. These results, together with reports from the literature suggest that all accepted cardiovascular risk factors are associated with abnormalities in the flow properties of blood. It is proposed that partly the same phenomena are involved in the genesis of atherosclerotic lesions and influence rheological properties of blood.

Adolescent↗
PubMed1986

Identification and characterization of mutations in Escherichia coli that selectively influence the growth of hybrid lambda bacteriophages carrying the immunity region of bacteriophage P22.

Mutations in two Escherichia coli genes, sipA and sipB, result in a specific inhibition of the growth of certain hybrid lambdoid bacteriophages, lambda immP22, that have the early regulatory regions and adjacent genes from bacteriophage P22. The sipB391 mutation maps near minute 56 and exerts the strongest inhibitory effect on the growth of the hybrid phages. The sipA1 mutation maps near minute 72 and plays an auxiliary role: enhancing the action of sipB391. Such a role is not limited to sipA1, since there is a similar enhancement by the nusA1 and nusE71 mutations. The Sip-imposed restriction on the growth of lambda immP22 phages is not observed if the phage carries a mutation in the c1 gene. Perhaps this reflects the fact that the c1 product regulates phage DNA replication and is a major determinant in the decision governing whether the phage takes the lytic or lysogenic pathway. Consistent with this idea is the observation that lambda immP22 DNA replication is severely inhibited in bacteria carrying the sipB391 mutation. It is suggested that sip mutations exaggerate the normal role of c1 in limiting lytic growth. This causes a failure in the expression of sufficient amounts of some or all of the lytic gene products required for phage growth.

Bacteriophage lambda↗