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Biomedical subjects

B Becker

Publications and source records attributed to B Becker.

At least 127 records · Page 7Linked to original sources
PubMed1984

In vitro studies on steroid metabolism by gonadal tissues from ambisexual teleosts. I. Conversion of [14C]testosterone by males and females of the protogynous wrasse Coris julis L.

Gonadal tissue of females, and primary and secondary males of the protogynous wrasse Coris julis were incubated with labeled [14C]testosterone. The large majority of metabolic products consisted of free, neutral steroids. Marked 11 beta-hydroxylation was restricted to testes from secondary males. 5 beta-Reduction of ring A was predominant in both types of males, whereas ovarian tissue from normal females produced a larger share of 5 alpha-androstanes. The metabolic products of ovaries from females that were injected with testosterone 7 days before incubation were similar to those of untreated females, although the ratio of 5 alpha/5 beta reduced steroids was changed toward the "male type".

Acetylation↗
PubMed1984

Intraocular pressure the day of argon laser trabeculoplasty in primary open-angle glaucoma.

Argon laser trabeculoplasty was performed in one eye of 57 phakic patients with primary open-angle glaucoma. The eyes received a mean of 78 +/- 7 treatments over 360 degrees to the anterior trabecular meshwork. The power was titrated to produce blanching without bubble formation. Increased intraocular pressure (range +1 to +22 mmHg) occurred in 30 of the 57 (53%) eyes 1 hour after treatment. Eight (14%) of these eyes had a clinically significant elevation defined by all of three criteria: (1) an intraocular pressure greater than 30 mmHg, (2) greater than a 30% increase over the mean prelaser intraocular pressure, and (3) greater than a 10 mmHg increase over the peak prelaser diurnal intraocular pressure curve. These eight patients received either oral glycerine or acetazolamide. A rebound increase in intraocular pressure requiring repeat medical treatment occurred in four of the eight eyes. Two additional eyes without a pressure elevation 1 hour after treatment showed a later elevation. This was first detected 4 hours postoperatively in one eye and 7 hours after treatment in another eye. The 1-hour postoperative measurement detected most patients with clinically significant increased intraocular pressure (8 of 10 eyes) but these required continued observation for rebound increases. Patients with advanced glaucomatous visual field loss should also be followed closely to detect late increases in intraocular pressure (2 of 10 eyes).

Adult↗
PubMed1984

The dyskinetic cilia syndrome in childhood. Modifications of ultrastructural patterns.

The syndrome of cilia dyskinesia is known as a heterogenous ciliary dysfunction caused by morphological defects of the dynein arms, the nexin links, the radial spokes and by the transposition of microtubules. Supernumerary tubules have been regarded as acquired morphological defects on the background of other bronchopathies. The report of a 9-year-old girl with the clinical signs of ciliary dyskinesis is considered to be an attribution to the clinical and pathological features of this syndrome. The girl's history of chronic bronchopulmonary infections and nasal polyposis resistant to therapy made her suspected to be ill of Kartagener's syndrome. The results of ultrastructural investigations of the mucosa from ciliated epithelium revealed a ciliary structural defect in the bronchi as well as in the nose and the sinuses with supernumerary microtubular doublets and singles, a decentration of the central tubules and shortened dynein arms. The regularity of the electron optical abnormalities implicates a systemic disorder of ciliated epithelium, which is to be summarized to the syndrome of cilia dyskinesis.

Bronchi↗
PubMed1984

Central effects of thyrotropin-releasing hormone and arginine vasopressin on intraocular pressure in rabbits.

Administration of either thyrotropin-releasing hormone (TRH) or arginine vasopressin (a-VP) into the rabbit third ventricle elevated intraocular pressure (IOP). IOP was increased 3.6 mmHg 45 min after TRH (10 ng/0.1 ml) administration and increased 6.4 mmHg 45 min following delivery of a-VP (5 micrograms/0.1 ml). Outflow facility and episcleral venous pressure were not altered by either agent. Estimated aqueous humor flow 45 min after third ventricle administration was increased 66% after TRH and 91% after a-VP delivery. Posterior chamber aqueous humor ascorbate was reduced 60 min after TRH administration. Pretreatment with either systemic or topical atropine prevented the TRH or a-VP induced increase in IOP. Body temperature (BT), which was unaltered after TRH administration, was elevated by third ventricle delivery of a-VP. The a-VP induced increase in BT was blocked by systemic pretreatment with either indomethacin or atropine.

Animals↗
PubMed1984

[Pulmonary dysplasia in infancy. Pathogenesis, pneumologic course studies and therapy possibilities].

Some premature and mature newborns who require intermittent positive airway pressure (IPPV) and high oxygen concentrations for respiratory distress syndrome develop characteristic damage of bronchi and bronchioles termed broncho-pulmonary dysplasia (BPD). According to the radiographic findings the changes are categorized into four progressive stages. Stage 1 describes a radiographic feature with a pattern of fine, faint granularity as it is characteristic for the hyaline-membrane-syndrome. Stages 2 to 4 represent diffuse interstitial emphysema, a bubbly appearance of the lung, atelectasis and a progressive fibrosis. Electronmicroscopic investigations of bronchial imprints could demonstrate a rarefication of the cilia and a ciliary damage which took the form of compound cilia. In addition, a marked increase of goblet cells in the bronchial mucosa as well as a metaplasia of the epithelial cells was present. These findings may be a prerequisite for chronic infections, and perpetuate a cycle which may result in chronic obstructive airway disease. The significance of bronchial and bronchiolar injury in children with BPD is said to be due to IPPV, high inspiratory oxygen concentrations, high fluid intake, vitamin E deficiency or an increased intrapulmonary pressure secondary to a patent ductus arteriosus. When pulmonary mechanics were measured in a baby-body-plethysmograph a high pulmonary resistance and a low dynamic compliance occurred at the first investigation after IPPV or oxygen administration. On re-examination there was a strong tendency to normalisation of x-ray findings and pulmonary mechanics, depending upon the time which elapsed between ventilation and re-examination. Current therapy has to be symptomatic and may include secretolytics, glucocorticoids and bronchodilators. The preventive interventions have to take into consideration ventilation techniques, restrictions in O2 and fluid intake.

Bronchi↗
PubMed1984

Serum cortisol concentrations in gilts and sows housed in tether stalls, gestation stalls and individual pens.

Three experiments were conducted to determine whether housing in tether stalls, gestation stalls or individual pens imposes a stress upon gilts and sows. Changes in serum cortisol concentrations were used as the indicator for stress. In the first experiment, gilts were placed in tether stalls and individual pens to determine cortisol concentrations after tethering and to see if this response was different from gilts that were previously tethered for two weeks. In the second experiment, gilts were tethered in order to determine if penning in tether stalls altered the circadian rhythm of cortisol. In the third experiment, breeding sows were placed in tether stalls, gestation stalls or individual pens to determine if a ten-hour profile of cortisol concentrations were altered and if such housing affected a sow's response to transfer to farrowing crates. The results indicate that the initial response to tethering varied among gilts and sows and this variation appeared to be due to previous penning and human handling experiences. When tethering was stressful, acclimation required up to four days. However, once acclimated, tethering resulted in higher morning concentrations which may be associated with the greater activity that occurs at this time. Housing in tether stalls, gestation stalls or individual pens was not a stress for breeding sows and did not alter sows' responses to transfer into the farrowing crate.

Animals↗
PubMed1984

The relationship between pharmacodynamics and pharmacokinetics in asthmatic children receiving a sustained-release formulation of theophylline.

Pharmacodynamic response as well as serum and saliva concentrations of theophylline were monitored in 15 children under a long term theophylline treatment. Respiratory parameters, such as vital capacity and total bronchial resistance all related to bronchodilatation, were measured by use of a bodyplethysmograph. Measurements were performed before treatment and during the steady state with respect to serum levels. Due to small differences between peak and trough concentrations, no correlations between serum concentrations and respiratory parameters were found during the steady state. However, some important respiratory parameters exhibit considerable differences with respect to pretreatment values. In conclusion, one can state that during the steady state, theophylline exerts a constant influence on bronchodilatation which depends only slightly on the concentration range achieved.

Adolescent↗
PubMed1983

Subclavian vein thrombosis in patients treated with infusion chemotherapy for advanced malignancy.

Twenty-two of 53 (42%) patients developed subclavian vein thrombosis (SVT) while receiving chemotherapy for advanced malignancy by an ambulatory pump constant infusion delivery system. The median time to thrombosis was 30 days (range, 5-270 days). Seven patients (36%) were asymptomatic and received no specific anticoagulation. Twelve patients (50%) received heparin followed by coumadin for 2 to 3 months. None of the 19 patients developed complications of the SVT. In three patients (14%), acute SVT progressed to complete or partial superior vena cava syndrome. The use of fibrinolytic therapy was successful in all three patients, and was adequate to lead to complete clinical resolution. Predisposing factors in the patient population included: (1) decreased antithrombin III levels prior to catheter insertion; (2) intrathoracic tumor, possibly creating low flow rates; and (3) improper or suboptimal home management of the catheter. The development of SVT was not related to the chemotherapeutic agent infused or the duration of therapy. The frequency of SVT in this patient population necessitates consideration of prophylactic methods in high-risk patients.

Antineoplastic Agents↗
PubMed1983

Microtubular reaction in human fibroblasts infected by cytomegalovirus. Brief report.

By the use of indirect immunofluorescence it is shown that "early" functions of human cytomegalovirus induce a loss of microtubuli in human foreskin fibroblasts within 12 hours postinfection (p.i.) which persists until about 60 hours p.i. At later times p.i. microtubular structures are eventually reestablished. Following depression during the initial 48 hours p.i. tubulin synthesis in infected cells is significantly enhanced during the initial 48 hours p.i. tubulin synthesis in infected cells is significantly enhanced during the late phase of the infectious cycle suggesting that the mechanisms regulating tubulin synthesis are not impaired.

Cytomegalovirus↗
PubMed1983

Long-term results of valve implants in filtering surgery for eyes with neovascular glaucoma.

Filtration surgery was performed with a pressure-sensitive, unidirectional valve implant in 79 eyes with neovascular glaucoma. The device consisted of an open Supramid tube (outside diameter 0.58 mm) sealed to a Silastic tube with a slit valve. The Supramid tube was inserted at the corneoscleral limbus 1 to 4 mm into the anterior chamber. The Silastic portion was located under a scleral flap. Of the 79 eyes, 53 had postoperative intraocular pressures less than or equal to 24 mm Hg after a mean follow-up period of 23.7 +/- 10.9 months. Bleb revision for external scarring was required in ten of these 53 eyes and postoperative medical therapy was required in 26. The valve implant failed to control intraocular pressure in 26 of the 79 eyes. Failure was secondary to scarring of the external bleb in 18 eyes and to closure of the internal Supramid tube in five eyes. Mortality during the follow-up period was high: 12 of the 53 successfully treated patients and five of the unsuccessfully treated patients died.

Adolescent↗
PubMed1983

Lack of correlation between ocular hypertensive response to topical corticosteroids and progression of retinopathy in insulin-dependent diabetes mellitus.

We studied the relationship of intraocular pressure responsiveness to topical corticosteroids and the development of retinopathy in 86 patients with insulin-dependent juvenile-onset diabetes available for long-term follow-up and examination during 1982. Eleven patients had background retinopathy at the initial examinations. High (GG) and intermediate (NG) corticosteroid responsiveness was more common in these 86 patients (13 high responders and 39 intermediate responders) than in previously reported volunteer series. Background diabetic retinopathy was present at the end of the study in 75 of the 86 patients and proliferative retinopathy was present in 29. The proportions of patients developing either type of retinopathy were similar among the low (NN), intermediate, and high response groups. The rate of diabetic retinopathy development was related to the duration of the disease and not to the intraocular pressure response to topical corticosteroids.

Administration, Topical↗
PubMed1983

Influence of beta-receptor-agonists and glucocorticoids on alpha- and beta-adrenoceptors of isolated blood cells from asthmatic children.

The most attractive "adrenergic theory" has proposed that in asthmatic patients the bronchial hyperreactivity might be caused by a decreased beta-receptor and an increased alpha-receptor responsiveness. Based upon the assumption that an abnormality of adrenergic receptors might be a general phenomenon, we have performed receptor-binding studies on lymphocytes and thrombocytes from asthmatic children who had and had not undergone treatment with beta-receptor agonists and/or glucocorticoids. Iodo-cyano-pindolol and tritium-labeled yohimbine were used as beta- and alpha-receptor ligands. The following results have been obtained: 1) The number and affinity of alpha- and beta-adrenoceptors on thrombocytes and lymphocytes showed no significant differences in asthmatic children and their age-matched controls. 2) In vivo treatment of asthmatic children with beta-receptor agonists immediately reduced the number of beta-receptors ("down regulation"). A reversal of the number of beta-receptors occurred within 1 day after cessation of the therapy. Although it appeared that some asthmatics with severe asthma have a reduced number of beta-receptors, in vivo treatment with beta-receptor agonists thus might mimic a beta-receptor blockade. 3) High-dose treatment with glucocorticoids increased the number of beta-receptors but left the alpha-receptors unaffected.

Adolescent↗
PubMed1983

Pharmacokinetics of dexamethasone in children.

A pharmacokinetic data analysis of plasma level data for dexamethasone obtained from children with various diseases and healthy adults was performed. A total of 33 subjects participated in the study. The results show: The pharmacokinetics of dexamethasone can be described satisfactorily within the frame of classic linear pharmacokinetic theory. The variance of important pharmacokinetic parameters is large. Therefore, if a close relationship between drug levels and therapeutic and adverse effects exists, which still has to be proved, optimal individual dosage regimens have to be calculated, guided by drug-level monitoring. When treating newborns, one should be aware that high drug levels are likely to occur, possibly necessitating a dose reduction.

Adolescent↗
PubMed1982

Fluorometric studies on the blood-retinal barrier in experimental animals.

Fluorophotometry was used to evaluate the blood-ocular barrier in rats following streptozocin-induced diabetes, experimental systemic hypertension, sodium iodate treatment, diet-induced galactosemia, and aldose reductase inhibitors. After administration of intravenous (IV) fluorescein sodium, diabetes, hypertension, or sodium iodate treatment resulted in an increased vitreous accumulation of IV fluorescein. Accumulation of dextran-labeled fluorescein (3,000 and 19,000 molecular weight [mol wt]) was not increased in diabetic or sodium iodate-treated animals. However, 3,000-mol wt dextran-labeled dye accumulated in the vitreous of hypertensive rats. The disappearance of fluorescein injected into the vitreous was significantly delayed in diabetic and sodium iodate-treated rats, whereas this rate was normal in hypertension animals. Galactosemia did not alter vitreous fluorophotometric measurements. Pretreatment for systemic effects with aldose reductase inhibitors did not correct the vitreous fluorophotometric measurements of diabetic rats.

Aldehyde Reductase↗
PubMed1982

Timolol and epinephrine: long-term evaluation of concurrent administration.

Thirty-two ocular hypertensive subjects were treated for 90 days with either 0.5% timolol maleate or 2% epinephrine hydrochloride twice daily to one eye and both drugs to the fellow eye. The ocular hypotensive effects of timolol and epinephrine were partially additive throughout the course of this study. On the 91st day, eyes treated with epinephrine had a 25.8% mean reduction of intraocular pressure from baseline, whereas their fellow eyes treated with epinephrine and timolol had a 33.9% reduction. Eyes treated with timolol had a 27.2% mean reduction of IOP, whereas fellow eyes treated with timolol and epinephrine had a 29% reduction. These results suggest that the majority of patients being treated with either drug are unlikely to have a substantial long-term reduction in IOP when the other drug is added to their therapeutic regimen.

Administration, Topical↗