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Biomedical subjects

R M Müller

Publications and source records attributed to R M Müller.

At least 19 recordsLinked to original sources

[Old and new interventional therapies in the treatment of symptomatic benign prostate hyperplasia (BPH)].

Benign Prostatic Hyperplasia is a common entity among the aging male population. Its prevalence is increasing with age and is around 80% in the over 80-years old. The androgen-estrogen ratio changes in favor of the estrogens, which leads to a growth of prostatic tissue, presenting histologically as hyperplasia. BPH can cause irritative or obstructive symptoms or both. Nowadays we speak of bladder storage or bladder voiding symptoms, summarised as LUTS (Lower Urinary Tract Symptoms). LUTS has a structural and a functional component, the structural being caused by the size of the adenoma itself the functional depending on the muscle tone of the bladder neck and the prostatic urethra. To investigate LUTS, we use validated symptom scores, sonography for residual urine and eventually a urodynamic evaluation. There are 3 grades of BPH. The indication for an interventional therapy is relative in BPH II, and absolute in BPH III. Prior to treatment, other diseases mimicking the same symptoms, have to be ruled out and adequatly treated. Electro-resection of the prostate (TUR-P) remains the standard therapy and the benchmark any new technology has to compete with. TUR-P has good short- and longterm results, but can be associated with a considerable perioperative morbidity, and the learning curve for the operator is long. The most promising of the newer techniques is the Holmium-Laser-Enucleation of the prostate (Laser-TUR-P), showing at least identical short- and median-term results, but a lower perioperative morbidity than TUR-P For several minimally-invasive techniques, indications are limited. TUMT TUNA, WIT and laser-coagulation all produce a coagulation necrosis of the prostatic tissue by thermic damage with secondary tissue shrinking. Urodynamic results however, are not comparable to TUR-P or Laser-TUR-P, and significantly more secondary interventions within 2 to 5 years are required. Minimal-invasive techniques present a favorable alternative for younger patients without complications of BPH, and for older patients with relevant comorbidities, and can usually be performed under local anaesthesia. The morbidity is low and further therapies remain possible later, if necessary.

Catheter Ablation↗

Mechanism of inhibition of neointimal formation by the angiotensin-converting enzyme inhibitor cilazapril. A study in balloon catheter-injured rat carotid arteries.

We investigated the mechanism of inhibition of neointima formation by the angiotensin-covering enzyme the carotid artery. We looked for the effects of cilazapril on all phases of the response to injury, ie, on proliferation of smooth muscle cells (SMCs) in the media, their migration, their proliferation in the neointima, and their disposition of extracellular matrix in the neointima. Although treatment was discontinued after 2 weeks, the inhibitory effect of cilazapril on neointimal formation was evident even 52 weeks after injury. The amount of extracellular matrix deposited in the intima during cilazapril treatment was decreased by 20% 2 weeks after injury, but no effect was seen if tissues were analyzed at 4 or 52 weeks. [3H]Thymidine-labeled cells (pulse labeling as well as 14-day continuous labeling) showed a decrease in SMC labeling in the tunica medica by 50%, but no inhibition in the labeling indices was seen in the neointima. The fraction of unlabeled neointimal cells in the cilazapril-treated rats as judged from continuous labeling experiments was inhibited by 86%. Taken together, these data suggest an antiproliferative effect on medial SMCs and an inhibition of SMC migration into the intima by cilazapril. Since intimal extracellular matrix deposition was only delayed, the decrease in medial SMC proliferation and subsequent migration seems to be the main reason for the reduction of neointima formation.

Angiotensin-Converting Enzyme Inhibitors↗

Noninvasive determination of pulmonary artery wedge pressure: comparative analysis of pulsed Doppler echocardiography and right heart catheterization.

To compare left ventricular filling variables as derived by transmitral pulsed Doppler echocardiography (tpDE) and hemodynamic variables as assessed at right heart catheterization (RHC), 104 ICU patients (64 male, 40 female) aged 26 to 73 yr (mean 54.6 +/- 10.3) without valvular heart disease were examined. Simultaneously with RHC, transmitral flow velocity profiles were obtained by tpDE, and the ratio of the velocity-time integrals of late diastolic active (A wave) and early diastolic passive inflow into the left ventricle (E wave) was calculated (A/E ratio). Invasively determined pulmonary capillary wedge pressure (WP) ranged from 3 to 36 mm Hg (median 13.35, 5%/95% 6/31 mm Hg). Linear regression analysis showed a highly significant correlation between the A/E ratio and WP (r = .98, p less than .001, standard error of the estimate [SEE] = 0.10). The A/E ratio also correlated with other hemodynamic variables such as cardiac output (r = -.68, p less than .001, SEE = 0.33), cardiac index (r = -.74, p less than .001, SEE = 0.31), and stroke volume index (r = -.68, p less than .001, SEE = 0.34). The interobserver agreement (derived by intraclass correlation analysis between two examiners) on the A/E ratio was high (r = .95, p less than .001, n = 26). We conclude that WP can be accurately determined noninvasively by tpDE. For the assessment of systolic ventricular function, tpDE is of limited diagnostic value.

Adult↗

Atropine treatment induced cholinergic supersensitivity at receptor and second messenger levels in the rat salivary gland.

Physiological, biochemical and morphological correlates of chronic treatment of rats with the classical muscarinic antagonist atropine for 14 days (20 mg kg-1 day-1 s.c.) were studied in submandibular salivary glands. The amount of saliva collected from submandibular glands following a single injection of isoproterenol (30 mg kg-1 i.p.) was significantly larger and had higher protein concentration in rats treated with atropine than in saline-treated animals. In the glands of atropine-treated rats a conspicuous increase in the amount of rough endoplasmic reticulum (RER) along with a decrease in the mucous volume was observed in the acinus when examined by light microscopy. Several biochemical changes were observed in an enriched plasma membrane fraction from the submandibular gland of the atropine-treated rats: (1) an increase in the number of muscarinic antagonist binding sites (31 + 3.4%), (2) a decrease in the specific activity of basal adenylate cyclase, (3) a significantly lower Vmax of the adenylate cyclase in the presence of GTP (10 microM) and varying concentrations of Mg2+ (0-22.5 mM) with no apparent change in affinity of the enzyme for Mg2+ but (4) higher magnitude of stimulation in the presence of GTP (100 microM), vasoactive intestinal polypeptide (5 microM), isoproterenol (100 microM), NaF (10 microM) and forskolin (10 microM). There was however no change in the density of beta-adrenergic receptors upon atropine treatment. In tissue slices from the submandibular glands of atropine-treated rats we found lower basal cAMP levels (decrease 29 +/- 6.9%) and no significant change in the phosphatidylinositol breakdown stimulated by carbachol (10(-6) to 10(-4) M). It appears that chronic blockade of an inhibitory muscarinic input to the adenylate cyclase system is compensated by lowered adenylate cyclase activity. Phosphoinositide metabolism is not subject to the same adaptation, suggesting that cAMP may be the pivotal second messenger in the supersensitive salivary response.

Adenylyl Cyclases↗

Essential fatty acid deficient rats in the study of cystic fibrosis: an X-ray microanalytical and ultrastructural study in chronically reserpinized rats.

Essential fatty acid (EFA) deficiency has been proposed as a major pathogenic mechanism for cystic fibrosis (CF) and EFA-deficient animals have been proposed as an animal model for CF. In the present study, the elemental composition and ultrastructure of the acinar cells of the submandibular and parotid gland of the pancreas of EFA-deficient rats were investigated by X-ray microanalysis and electron microscopy. The effects of EFA-deficiency were compared to changes in these exocrine glands in chronically reserpine-treated rats, an established animal model for CF. EFA-deficiency did not cause any significant changes in the elemental composition of the acinar cells of the submandibular or parotid gland, or of the pancreas. The changes in elemental composition induced by reserpine treatment were only slightly modified by EFA-deficiency, mainly towards normalization. EFA-deficiency resulted in the presence of abnormal, electron translucent, zymogen granules in the parotid gland and in a reduction of the number of zymogen granules in pancreatic acinar cells. Since EFA-deficiency in rats only causes minor changes in structure and elemental composition of salivary glands and pancreas, and does not potentiate the effect of chronic reserpine treatment on these tissues, it is concluded that EFA-deficiency is likely to be of minor importance in the exocrine gland disturbances in CF.

Animals↗

Noninvasive measurement of left ventricular filling pressures by means of transmitral pulsed Doppler ultrasound.

In 54 consecutive patients, ages 59 +/- 11 years, the transmitral diastolic flow velocity profile was derived by means of pulsed Doppler echocardiography simultaneously with right-sided heart catheterization. In 30 of them, ages 57 +/- 10 years, left-sided heart catheterization was performed at the same time. The sample volume was positioned exactly in the mitral anulus plane, bisecting the anulus. The ratio of the time-velocity integrals of the A wave (atrial contraction) and E wave (early filling) was calculated (A/E ratio of integrals). Linear regression analysis showed a highly significant linear correlation of the A/E ratio of integrals with regard to left ventricular (LV) end-diastolic pressure (r = 0.98, p less than 0.001) and pulmonary capillary wedge pressure (r = 0.98, p less than 0.001). The A/E ratio of integrals also correlated with other hemodynamic parameters, such as cardiac output (r = -0.73, p less than 0.001), cardiac index (r = -0.74, p less than 0.001) and stroke volume index (r = -0.65, p less than 0.001). For 19 additional patients, ages 55 +/- 8 years, the values of LV end-diastolic pressure and pulmonary capillary wedge pressure were calculated by means of the corresponding formulas from the first data set. The correlation between the calculated and invasively measured LV filling pressures expressed in terms of intraclass correlation coefficients shows highly significant correlations for both LV end-diastolic pressure (intraclass correlation coefficient = 0.99, p less than 0.001) and pulmonary capillary wedge pressure (intraclass correlation coefficient = 0.99, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗

Transcriptional control of the rat heme oxygenase gene by a nuclear protein that interacts with adenovirus 2 major late promoter.

Induction of rat heme oxygenase is mediated by at least two factors: its substrate heme and heat shock (Shibahara, S., Müller, R.M., and Taguchi, H. (1987) J. Biol. Chem. 262, 12889-12892). We have identified the cis-acting element of the rat heme oxygenase gene (HO gene), that was specifically bound by a nuclear protein prepared from rat glioma cells. We have termed this protein as heme oxygenase transcription factor (HOTF), whose estimated molecular weight is about 40,000. The element identified is CCACCACGTGACTCGAG (-51/-35) located just upstream of TATA-like sequence. The functional studies indicate that this sequence is required for the accurate and efficient initiation of transcription from the HO gene promoter. Since the HOTF-binding element is similar to the upstream promoter sequence (UPS) of the adenovirus 2 major late promoter (Ad2MLP), we examined whether rat HOTF is homologous to the upstream stimulatory factor (USF) or major late transcription factor previously identified in HeLa cells, which interacts with the UPS and activates the transcription from the Ad2MLP. HOTF specifically binds to the UPS of Ad2MLP, whereas HOTF failed to form a stable complex with the mutated HOTF-binding element lacking a GTGA sequence (-44/-42 of the HO gene), the sequence of which is identical to a core sequence of the USF-binding sites. Moreover, we show that like USF, HOTF is heat stable. These results suggest that HOTF may be homologous to USF or the major late transcription factor. Since USF is present in uninfected cells, it is conceivable that the expression of the HO gene is regulated at least in part by USF.

Adenoviruses, Human↗

Mechanism of action of calcitonin on secretion in rat submandibular gland.

Calcitonin (CT) was found to reduce the initial flow of pilocarpine-stimulated saliva from the submandibular glands in the rat. Although there was a concomitant increase of the concentration of calcium and protein in the saliva, the calcium/protein ratio was not significantly affected. CT also caused a significant increase of the potassium concentration in submandibular saliva. Both in vivo and in vitro, CT inhibited the production of cyclic AMP (cAMP) both in the absence and in the presence of forskolin. This decrease in intracellular cAMP levels could result in an inhibition of mucus secretion, which would explain the previously observed calcitonin-induced intracellular accumulation of mucus in the submandibular gland acinar cells. CT did not affect the cytoplasmic free Ca2+ concentration (as measured with fura 2) in isolated submandibular acini either in the absence or in the presence of cholinergic or adrenergic agonists. These results indicate that the inhibition of fluid secretion in the submandibular gland by calcitonin must be located distal to changes in [Ca2+]i. It can be concluded that CT affects both mucus and fluid secretion in the submandibular gland, but that only the inhibition of mucus secretion can as yet be explained by an effect at the level of the second messenger.

Adenylyl Cyclases↗

X-ray microanalysis of mammalian salivary glands.

X-ray microanalysis was used to study the elemental composition of major salivary glands in rat and man. The elemental composition of the acinar cells is influenced by a variety of factors. Stimulation of fluid secretion by cholinergic, alpha-adrenergic or peptidergic agonists leads to a sustained increase of the Na/K ratio. The elemental composition and ultrastructure of the acinar cells of rat submandibular gland, as well as flow rate and composition of pilocarpinestimulated submandibular saliva are significantly affected by thyroxine, but less by the synthetic glucocorticoid dexamethasone. Hypercalcemia (induced by chronic vitamin D treatment) as well as hypocalcemia (induced by calcitonin) cause accumulation of intracellular mucus in the submandibular acinar cells, with concurrent increase in the cellular calcium concentration, and a significantly decreased flow rate after pilocarpine stimulation. Several animal models have been proposed for the generalized exocrinopathy cystic fibrosis (CF), which may be caused by a defective regulation of chloride transport in epithelial cells. A potential new model is proposed: the chronically furosemide-treated rat, which shows several abnormalities in salivary gland structure and function that parallel the abnormalities found in the human disease. Another experimental model of potential interest in the study of CF is short-term treatment of experimental animals with the adenylate-cyclase inhibitor alloxan.

Animals↗

Human heme oxygenase cDNA and induction of its mRNA by hemin.

Hemin treatment increased both activity and mRNA level of heme oxygenase in human macrophages. Using poly(A)-rich RNA prepared from human macrophages treated with hemin, we have constructed a cDNA library in the Okayama-Berg vector. The human heme oxygenase cDNA was isolated by screening this library with a rat cDNA and was subjected to nucleotide sequence analysis. The deduced human heme oxygenase is composed of 288 amino acids with a molecular mass of 32,800 Da. The homology in amino acid sequences between rat and human heme oxygenase is 80%. Like rat heme oxygenase, human enzyme has a putative membrane segment at its carboxyl terminus, which is probably essential for the insertion of heme oxygenase into endoplasmic reticulum. Both rat and human heme oxygenase have no cysteine residues. Recently we have shown that rat heme oxygenase is a heat-shock protein [J. Biol. Chem. 262, 12889-12892 (1987)], and therefore we examined the effects of heat treatment on the induction of heme oxygenase in human macrophages and glioma cells. In contrast to hemin treatment, heat treatment had no apparent effects in either human cell line on the activity of heme oxygenase and its mRNA levels. These results suggest that human heme oxygenase may not be a heat-shock protein.

Amino Acid Sequence↗

Changes in glycoconjugates in rat submandibular gland after chronic treatment with reserpine and isoproterenol.

Chronic treatment of rats with reserpine, isoproterenol, or a combination of these two agents has been suggested as a means to produce an experimental animal model for the chronic exocrinopathy cystic fibrosis. The effect of these treatments on glycoconjugate distribution in rat submandibular gland acinar cells was investigated by quantitative lectin cytochemistry. Significant changes in wheat-germ agglutinin (WGA), soy bean agglutinin (SBA) and concanavalin A (Con A) binding sites in the mucus granules were observed, but peanut agglutinin (PNA) binding was not significantly affected. The quantitative changes in glycoconjugates in the acinar cells of the submandibular gland could be a possible explanation for the increased binding of calcium by the intracellular mucus noted in previous studies on these animal models.

Animals↗

Molecular basis for the heterogeneity of human tyrosinase.

A cDNA clone, pHT gamma 1, representing human tyrosinase mRNA was isolated by screening a melanoma cDNA library with a synthetic oligonucleotide complementary to a segment of the human tyrosinase cDNA, Pmel 34 [Kwon et al. (1987) Proc. nat. Acad. Sci. USA 84, 7473-7477]. However, there are a number of differences in the nucleotide sequence between two cDNAs, pHT gamma 1 and Pmel 34, particularly in the region coding for the carboxyl terminus of the enzyme (putative exon 5). We therefore cloned the genomic DNA segment carrying the exon 5 of the human tyrosinase gene by screening a human placental genomic DNA library with a cloned cDNA probe. The nucleotide sequences of human tyrosinase cDNA as well as part of its gene were determined. Mature human tyrosinase is composed of 511 amino acids with a molecular weight of 58,000. We provide evidence for the presence of at least two species of human tyrosinase mRNA generated by alternative splicing in human pigmented melanoma cells.

Amino Acid Sequence↗

Transcriptional control of rat heme oxygenase by heat shock.

A heat shock element is located in the 5'-flanking region of the rat heme oxygenase gene (HO gene). The incubation of rat glioma cells at 42 degrees C or with hemin at 37 degrees C increased the levels of heme oxygenase mRNA within 1 h and produced a maximum at 3 h (at least a 20-fold increase). In both treatments, the heme oxygenase activity started to increase after a lag period of about 1 h and reached a maximum value at 5 h. There was an apparent additive effect of both treatments on the heme oxygenase induction. Studies with actinomycin D and cycloheximide suggested that both heat shock and hemin acted at the transcriptional level to induce heme oxygenase. Therefore, we analyzed the transient expression of chimeric fusion genes harboring the promoter of the rat HO gene ligated to the Escherichia coli gene gpt in rat glioma cells and in K1735 mouse amelanotic melanoma cells. The 5'-flanking region of the rat HO gene bearing the heat shock element conferred the heat inducibility of gpt RNA production in both cell lines; however, hemin treatment did not induce gpt RNA. These results indicate that rat heme oxygenase is a heat shock protein and that hemin induces heme oxygenase through a different mechanism from heat shock.

Animals↗

Nucleotide sequence and organization of the rat heme oxygenase gene.

Heme oxygenase, an essential enzyme of heme catabolism, is inducible by its substrate heme, by heavy metals, and by various other substances. To study the molecular mechanisms of the induction of heme oxygenase, we isolated the heme oxygenase gene from a rat genomic DNA library using cloned cDNA as hybridization probes and determined its complete nucleotide sequence. The gene is composed of 6830 nucleotides, and is organized in four introns and five exons. The transcription initiation site was identified by S1 nuclease mapping analysis. Using HeLa cell lysate, we confirmed that the transcription of cloned heme oxygenase gene is initiated accurately at the assigned initiation site. In the 5'-flanking region of the heme oxygenase gene, we found several potential binding sites for different transcription factors: a transcription factor Sp1, a positive regulator for the control of amino acid synthesis (GCN4), a heat shock transcription factor, and a metal-dependent transcription factor. Furthermore, the intron 1 contains the sequence that shows about 65% homology to that of the neuronal identifier sequence, a possible enhancer element.

Animals↗

Abnormal 45Ca fluxes in dispersed submandibular acini of rats treated with reserpine.

The uptake and efflux of the isotopic tracer 45Ca were compared in dispersed submandibular acini of both control rats and rats treated with seven daily doses of reserpine (0.5 mg/kg, i.p.). Tracer uptake occurred in a time-dependent manner in both types of acini and reached 8.4 +/- 0.2 and 8.0 +/- 0.2 pmol/mg protein, respectively, in acini from control and treated animals after 60 min of incubation. Uptake of tracer was 2.35 nmol/mg DNA in control cells and 4 nmol/mg DNA in cells from treated rats at 60 min. 45Ca uptake (per mg protein) was enhanced in control acini 48% by 20 mumol/L epinephrine; 38% by 50 mumol/L carbachol; and 23% by 10 mumol/L isoproterenol. A similar order of potency was observed when uptake was expressed per mg DNA. In acini from reserpine-treated rats, 45Ca uptake (per mg protein) was increased 53% by epinephrine, 39% by isoproterenol, and only 8% by carbachol. The same enhanced effect of isoproterenol and lack of effect of carbachol were observed when uptake was calculated per mg DNA. In the absence of secretagogue, efflux of 45Ca from tracer-pre-loaded acini was larger in acini from reserpine-treated rats (53%) than in control acini (36%). Whether expressed in terms of mg protein or mg DNA, this efflux was increased in control acini 35% by epinephrine, from 25 to 28% by isoproterenol, and 17% by carbachol. In acini of reserpine-treated rats, epinephrine increased 45Ca efflux 20%, isoproterenol from 25 to 28%, and carbachol from 14 to 15%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Effects of reserpine treatment on the ultrastructure of rat parotid and submandibular gland.

The chronically reserpine-treated rat has been used as an animal model for the disease cystic fibrosis, a generalized exocrinopathy. Ultrastructural changes in the parotid and submandibular gland occurring during the seven-day treatment with reserpine were studied by transmission electron microscopy. In the parotid gland, marked changes were observed in the size and structure of the zymogen granules. In fasted control animals, most parotid acinar cells have granules with a virtually homogeneous, electron-dense appearance. During the first three days of treatment, most cells have enlarged, electron-translucent granules. After the third day, and most pronounced at day six and seven, many granules are irregularly electron-dense. In the submandibular gland, reserpine causes a gradual increase in the relative volume of the cell that is occupied by mucus. The ultrastructural changes are discussed in relation to metabolic and biochemical effects of reserpine treatment on salivary glands.

Animals↗

X-ray microanalysis of goblet cells in bronchial epithelium of patients with cystic fibrosis.

The elemental composition of goblet cells in bronchial epithelium was investigated by X-ray microanalysis. Biopsies were obtained from the left main bronchus, shock-frozen and freeze-substituted. In comparison to the control group (patients with chronic bronchitis), the goblet cells of patients with cystic fibrosis (CF) contained significantly more calcium. The analysis also indicated higher sulphur levels and lower potassium levels in the goblet cells of CF patients. Detailed analysis of a control biopsy showed that the calcium level in the mucous cells of the submucosal glands was considerably higher than that in the goblet cells. Although the data point to a higher calcium content of goblet cell mucus in CF patients, the significance of this finding for the calcium content of the tracheobronchial secretions in CF patients is unclear.

Adult↗