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Biomedical subjects

A Weber

Publications and source records attributed to A Weber.

At least 433 records · Page 24Linked to original sources
PubMed1987

[Symptoms and findings of giant cell arteritis in the area of the ear, nose, and throat].

Jaw claudication (angina masticatorica) is one of the best known signs of giant cell arteritis (Horton's arteritis). Other symptoms are pain, swelling, redness and necrosis of the face, mouth, and nasal mucosa (ulcerous pharyngitis, glossitis) leading to disturbances in swallowing. In rare cases there are alterations of smelling and hearing. The knowledge of such non-characteristic symptoms can be of diagnostic importance in cases of Horton's arteritis without local signs in the temporal area, visual failure or polymalgia rheumatica.

Giant Cell Arteritis↗
PubMed1987

[The cat as a possible infection source for Chlamydia psittaci keratoconjunctivitis in humans].

Acute follicular keratoconjunctivitis in a 25-year-old female patient was diagnosed as an infection with Chlamydia psittaci supposedly originating from a household cat with similar symptoms. The diagnosis was based on clinical symptoms, the appearance of Chlamydia-psittaci-specific IgM in the patient and the cat, and excluded other pathogenic agents. Chlamydiae organisms could not be isolated, probably due to prior antibiotic treatment. Two weeks of continuous treatment led to complete recovery of the patient and the cat. Other zoonotic infections of conjunctivitis in cats and keratoconjunctivitis in man caused by Chlamydia psittaci are mentioned.

Adult↗
PubMed1986

[Prolactinoma in the male].

In a retrospective study the medical records of 13 male patients with macroprolactinomas were evaluated concerning anamnestic data, clinical, endocrinological and localisation-diagnostic findings as well as therapeutic measures. The main symptoms were disturbances of vision and impaired potency and impaired libido, respectively. The ophthalmological complaints nearly exclusively caused the patients to see the doctor. Clinically the signs of hypogonadism were found. The diagnosis was ascertained by increased serum prolactin levels, ophthalmological findings, X-ray of the sella, cranial computed tomography as well as angiography of the carotid. The operative treatment did not show any normalization of the serum prolactin levels. The rate of recidivations after exclusive operative treatment was high. An additional medicamentous therapy with dopamine agonists is nearly always necessary after operation. Whether or not bromocriptine shall be used as primary therapy, must be decided on in the individual case.

Adolescent↗
PubMed1986

Different calcium dependence of the capping and cutting activities of villin.

The concentration of ionized calcium required for the capping of barbed filament ends by villin is about 4 orders of magnitude lower than that required for the cutting activity of villin. Capping was 50% complete at about 10-30 nM Ca2+, a level expected in resting cells, whereas the cutting rate was half-maximal at about 200 microM, making it possible to completely separate filament capping from filament cutting. Analysis of capping in terms of coupled equilibria between calcium binding to villin and calcium-villin binding to the barbed ends of actin filaments gives a value of 10(16)-10(17) M-2 for the product of the two binding constants. By comparison the binding constant reported for the rapidly exchanging calcium sites on villin is 2 X 10(5) M-1 and that for binding of calcium-saturated villin to barbed ends has a minimum value of 10(11) M-1 giving a product of 2 X 10(16) M-1. The close similarity of the two sets of values suggests that capping is regulated by the rapidly exchanging calcium sites on villin. In terms of coupled equilibria the calcium requirement for filament capping decreases with increasing concentrations of free villin. The scant information on the mechanism of cutting allows only an estimate of the maximal value for the calcium-binding constant of the site regulating cutting which is about 2-5 X 10(3) M-1. Cutting is followed by rapid capping of the newly released barbed ends.

Actins↗
PubMed1986

[Decision aids in determining therapy of breast cancer by preoperative staging using sonography and computerized tomography].

In a prospective study the preoperative ultrasonography of 54 cases of carcinoma of the breast was able to predict the pTNM staging precisely in 83.3% for tumor size and in 72.3% for lymphnode metastases. Multicentric-multifocal carcinomas were diagnosed by ultrasonography in 10 of 13 patients, better than by mammography (6 of 13). The CAT scan is indicated only in advanced tumor stages. The preoperative staging by ultrasonography enables with more precision planning and differentiated therapy of the carcinoma of the breast, especially in view of breast-preserving therapy.

Breast↗
PubMed1986

The effect of low ATP concentrations on relaxation in the myosin regulated myofibrils from scallop.

Troponin-tropomyosin-regulated myofibrils show a significant increase in ATPase activity and contract in the absence of calcium when the ATP concentration falls significantly below the saturation level. By contrast, the ATPase of the myosin-regulated myofibrils of scallop striated muscle was not activated in the absence of calcium when the ATP concentration was lowered to 10mM. Nevertheless, a very small fraction of crossbridges were active at 10mM ATP resulting in very slow myofibrillar shortening. In contrast to the behaviour of rabbit contractile proteins there was no correlation between myofibrillar shortening and ATP induced turbidity changes of actomyosin taken from scallop.

Actomyosin↗
PubMed1986

Pupillary responses to syntactic ambiguity of sentences.

Pupillary responses have proven to be reliable physiological correlates of cognitive effort in a variety of tasks, including language processing. To investigate the relation between psychological and syntactic complexity 20 syntactically ambiguous sentences, balanced for bias, were presented to 16 subjects, while their pupil size was continuously measured. These sentences could be read as verb oriented (syntactically more complex) or object oriented (syntactically less complex). Principal components analysis of pupillary movements revealed that verb-oriented readings, resulted in greater pupillary dilations than object-oriented readings, indicating that syntactically more complex sentences, as determined via a formal grammar, require greater cognitive effort in processing. This is viewed as further evidence for the notion that syntactic and psychological complexity are related. High- and low-bias sentences did not induce comparable differences in pupillary movements, indicating that the "multiple meaning theory" may have to be modified.

Adult↗
PubMed1986

Characteristics of the asparagine-linked oligosaccharide from honey-bee venom phospholipase A2. Evidence for the presence of terminal N-acetylglucosamine and fucose in an insect glycoprotein.

Eighty-eight % of phospholipase A2 from honey-bee (Apis mellifica) venom is glycosylated. Its single oligosaccharide exists in several structural variants, which represent consecutive stages of the "N-glycan processing pathway". The carbohydrate carries terminal fucosyl and N-acetyl-glucosaminyl residues. This is in contrast to earlier reports which suggest the lack of respective glycosyl-transferases in insects.

Acetylglucosamine↗
PubMed1986

The influence of early postnatal overnutrition on peripheric thyroxine metabolism in rats.

The influence of postnatal overnutrition on thyroid metabolism in later life was studied in male rats reared in small nests (2 pups per dam). At an age of 3 months postnatally overfed rats differ from normally bred rats (12 pups per dam) by a significant higher thyroxine and lower triiodothyronine concentration in plasma. Kinetic data of thyroxine metabolism point out a lower fractional turnover rate and a lower metabolic clearance rate per 100 g body mass corresponding with a reduced 131I-uptake by the thyroid gland. A lower energy intake per metabolic mass unit and a lower energy need for maintenance in postnatally overfed rats calculated from intake and body mass development are discussed in respect of correlations between changes of thyroid hormone metabolism and efficiency of energy utilization.

Animals↗
PubMed1986

An actin-nucleating activity in polymorphonuclear leukocytes is modulated by chemotactic peptides.

We examined the actin-nucleating activity in polymorphonuclear leukocyte lysates prepared at various times after chemotactic peptide addition. The actin nucleation increases two- to threefold within 15 s after peptide addition, decays to basal levels within 90 s, and is largely independent of cytoplasmic calcium fluxes. The peptide-induced nucleation sites behave as free barbed ends and therefore may increase the level of polymerized actin in vivo. The new nucleation sites may also determine the cellular sites of actin polymerization. This localization of actin polymerization could be important for the directional extension of lamellipodia during chemotaxis.

Actin Cytoskeleton↗
PubMed1986

Pharmacokinetics of rifampin in children. I. Multiple dose intravenous infusion.

The pharmacokinetics of intravenous rifampin (280 +/- 78 mg/m2) were investigated during multiple dose administration in 12 pediatric patients aged 3 months to 12.8 years. Serum rifampin concentration data were fit to a linear one-compartment model. There was a significant effect of duration of therapy on rifampin clearance (Cl) and half-life (t1/2) (p = 0.027 and p = 0.048, respectively). A mean increase of 52.0% in Cl (3.10-4.72 L/h/m2) and a mean decrease of 27.0% in t1/2 (2.38-1.73 h) were observed when data collected during the first 2 days of therapy were compared with data collected following 8 or more days of therapy. Peak concentrations extrapolated to the end of infusion were 27.0 +/- 8.2 micrograms/ml, and concentrations at 8 h after the dose were only 1.9 +/- 1.5 micrograms/ml. There was no significant effect of duration of therapy on these concentration values. There was no correlation between Cl and age or administered dose. Intrapatient variation in Cl was great, as evidence by the lack of correlation of initial Cl values with subsequent values in individual patients (r = 0.259). It would appear that dosage intervals may need to be shortened from 12 to 8 h during continuous therapy, and that periodic measurement of rifampin concentration may be required.

Age Factors↗
PubMed1986

Pharmacokinetics of rifampin in children. II. Oral bioavailability.

The absolute bioavailability of oral rifampin was determined in 20 pediatric patients. Intravenous doses of rifampin (mean 287 mg/m2) were compared with p.o. doses (mean 324 mg/m2). Serum concentrations of rifampin, 25-O-desacetylrifampicin, and 3-formylrifamycin SV were determined by high performance liquid chromatography. Following a 1/2-h intravenous infusion, serum rifampin concentrations declined in a monoexponential fashion. Pharmacokinetic analysis of the rifampin serum concentration data indicated that only 50 +/- 22% of a freshly prepared p.o. suspension was absorbed. The rifampin elimination half-life following i.v. administration (2.25 +/- 0.64 h) was not different from that observed following p.o. dose administration (2.61 +/- 1.35 h). Peak rifampin concentrations were significantly higher following i.v. administration when corrected to a 300 mg/m2 dose (27.4 vs. 9.1 micrograms/ml, respectively, p less than 0.0001) than after p.o. administration. The peak concentration following a p.o. dose occurred at 2.0 +/- 0.9 h. The ratio of desacetylrifampicin to rifampin areas under the curves were similar for i.v. and p.o. routes of administration (0.23 vs. 0.19), suggesting linear metabolism of rifampin to this metabolite. 3-formylrifamycin SV concentrations were lower than those of desacetylrifampicin and were detectable in less than half of the patients. The results of this study indicate the need for larger p.o. doses when serum concentrations similar to those obtained following intravenous doses are desired.

Administration, Oral↗