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Biomedical subjects

B Linder

Publications and source records attributed to B Linder.

At least 37 records · Page 2Linked to original sources
PubMed1994

Evidence against roles for pertussis toxin sensitive G proteins or diacylglycerol generation in insulin-like growth factor-1 stimulated DNA synthesis in MG-63 osteosarcoma cells.

A pertussis toxin-sensitive G protein has been reported to play a role in the mitogenic response to insulin-like growth factor-I (IGF-I) in mouse fibroblasts, and diacylglycerol generation has been shown to accompany growth stimulation by IGF-I of several cell lines. We have examined the roles of pertussis toxin sensitive G proteins and diacylglycerol generation in signaling by the insulin-like growth factor-I receptor in a cell line that is very responsive to IGF-I, the human osteosarcoma cell line, MG-63. Pertussis toxin failed to inhibit IGF-I induced [3H]-thymidine incorporation into DNA. Furthermore, the stable analog GTP gamma S had no effect on the binding of 125I-labelled IGF-I to MG-63 membrane preparations. Following addition of IGF-I to growth-arrested MG-63 cells there was no increase in diacylglycerol levels over 30 min. We conclude that the activated IGF-I receptor does not use pertussis toxin sensitive G proteins or diacylglycerol generation in a pathway leading to DNA synthesis in MG-63 cells.

Cell Membrane↗
PubMed1992

A slow anion channel in guard cells, activating at large hyperpolarization, may be principal for stomatal closing.

Slowly activating anion channel currents were discovered at micromolar 'cytoplasmic' Ca2+ during patch-clamp measurements on guard-cell protoplasts of Vicia faba and Xanthium strumarium. They activated at potentials as low as -200 mV, with time constants between 5 and 60 s, and no inactivation. The broad voltage dependence exhibited a current maximum near -40 mV. The single-channel open time was in the order of seconds, and the unitary conductance was 33 ps, similar to that of the already described 'quick' anion channel of guard cells. Because of its activity at low potentials, the slow anion channel may be essential for the depolarization of the plasmalemma that is required for salt efflux during stomatal closing.

Anions↗
PubMed1991

Evidence for a dissociation between cardiovascular and behavioral reactivity in the spontaneously hypertensive rat.

Spontaneously hypertensive rats of the Okamoto strain (SHR) were compared with normotensive rats of the Wistar-Kyoto strain (WKY) on the acoustic startle response in rats prepared for simultaneous blood pressure recordings. Blood pressure was continuously recorded by means of an indwelling cannula in the caudal tail artery. The presentation of the startle stimulus caused a blood pressure response in both strains consisting of an initial increase in blood pressure followed by a decrease and after that a longer lasting, but less pronounced second increase in pressure. The startle-elicited increase in blood pressure was significantly elevated in SHRs and at the same time the acoustic startle response was depressed as compared to WKY rats. These data indicate a dissociation between cardiovascular and behavioral reactivity in the SHR.

Acoustic Stimulation↗
PubMed1990

Osteoarthritis of the hip and knee in Saudi Arabia.

The records of 4721 patients, who were registered at a Primary Health Care Centre in the Eastern Province of Saudi Arabia during a 18 month period, were reviewed. One hundred and sixty-six (3.5%) had osteoarthritis of the hip or knee. The ratio of hip to knee was 1:80 which is very low compared to other populations, and the possible causes for this are discussed.

Age Factors↗
PubMed1990

Circulatory monitoring of children during anaesthesia in low-field magnetic resonance imaging.

Anaesthesia for patients in a Magnetic Resonance Imaging (MRI) scanner provides some problems for the design of both the anaesthetic and the monitoring equipment. This report presents a technique for continuously displaying the heart rate during anaesthesia for children in an MRI scanner. The monitoring system used light to detect differences in skin capillary circulation, and the light was transferred to and from the patient via fiberoptic cables. After amplification, the signal was displayed "on line" on a cardioscope, thus continuously presenting heart rate and, in part, a qualitative view of the skin vascular resistance.

Adolescent↗
PubMed1989

Alternate day prednisone therapy in congenital adrenal hyperplasia: adrenal androgen suppression and normal growth.

Daily glucocorticoid therapy of children with congenital adrenal hyperplasia (CAH) frequently results in a suboptimal mature height. In contrast, pharmacological doses of prednisone given on alternate days generally allow normal growth in children with autoimmune, hematological, and renal disorders. Moreover, alternate day prednisone therapy suppresses adrenal androgen secretion on both the day on and the day off therapy in patients with systemic lupus erythematosus. We hypothesized that alternate day prednisone therapy might be efficacious in the treatment of CAH. To evaluate this hypothesis, we studied an 11-yr-old girl with salt-losing 21-hydroxylase deficiency and severe asthma treated with alternate day prednisone therapy (20 mg every other day) for over 3 yr. During this period her linear growth was along the 65th percentile, and her bone age paralleled her chronological age. Pubertal development was normal, and she had no signs of androgen or glucocorticoid excess. In keeping with her clinical picture, basal (24-h samples drawn every 60 min) and ovine CRH-stimulated plasma adrenal androgen (dehydroepiandrosterone sulfate and delta 4-androstenedione) concentrations and 24-h urinary 17-ketosteroid excretion were low on both the day on and the day off prednisone. However, her plasma ACTH and 17-hydroxyprogesterone levels were markedly elevated on both days. The adrenal androgen suppression, therefore, appeared independent of the level of ACTH, suggesting different regulation of the zona fasciculata and the zona reticularis. GH secretion, assessed by measurement of plasma GH every 20 min for 48 h, was normal on both the on and off days of prednisone therapy. Therefore, in this girl pharmacological doses of prednisone given on alternate days caused sustained adrenal androgen suppression and allowed normal growth and pubertal development, despite persistently elevated plasma ACTH and 17-hydroxyprogesterone levels.

17-alpha-Hydroxyprogesterone↗
PubMed1988

Choroidal hematoma and effusion: evaluation with MR imaging.

To evaluate the usefulness of magnetic resonance (MR) imagining in the evaluation of choroidal pathologic conditions, the authors studied 15 patients with either choroidal hematoma or choroidal effusion with a 1.5-T MR imager. These two lesions were reliably distinguished from each other on the basis of MR findings. Choroidal hematomas appeared as lenticular-shaped masses in the wall of the eyeball, and signal intensity depended on the age of the hematoma. Choroidal effusions appeared as crescentic or ring-shaped areas of increased signal on both T1- and T2-weighted images in an anatomic distribution corresponding to the choroidal and suprachoroidal spaces.

Adult↗
PubMed1987

Paraorbital tumors and tumor-like conditions: role of CT and MRI.

Tumors and tumor-like conditions of the paraorbital tissues that affect the eye usually require CT or MR imaging for complete evaluation. This article provides an overview of the wide variety of pathologic conditions to be considered when a paraorbital tumor is discovered or suspected. Some of the CT and MR imaging features of these disorders that aid in the differential diagnosis are reviewed.

Adenocarcinoma↗
PubMed1987

CT and MRI of orbital abnormalities in neurofibromatosis and selected craniofacial anomalies.

This article begins with a discussion of normal orbital anatomy and the terminology involved in the description of abnormalities of the orbit. Case reports of patients with neurofibromatosis or with a craniofacial anomaly are presented, and the characteristic orbital findings on both CT and MRI are reviewed. Thus the radiologist's role and the value of CT and MRI in the overall treatment of these often complex abnormalities are elucidated.

Adolescent↗
PubMed1981

Model of serine proteases charge relay system -- PCILO study.

The PCILO (Perturbative Configuration Interaction Using Localized Orbitals) method had been used to determine the electronic structure of the active center of serine proteases. The results show that the carboxyl group of the aspartic acid residue is the ultimate proton acceptor of the catalytic triad (Asp, His, Ser)-. In the absence of a substrate the negative charge of the active centre is delocalized, causing polarization of the Ser O gamma-H bond and an increase of the nucleophilicity of imidazole His. The hydration of the model charge relay system is also investigated.

Binding Sites↗
PubMed1979

On the mechanism of the post-asymptotic CR decrement phenomenon.

Three experiments with 49 dogs explored the decrease in CR magnitude that sometimes occurs when CS-US pairings are continued beyond those needed to reach maximum CR magnitude. The first experiment confirmed the existence of the phenomenon, obtaining less conditioned excitation after 300 CS-US trials than after 18 CS-US trials. The second experiment demonstrated that the phenomenon is not dependent upon paired CS-US presentations because 18 CS-US pairings yielded little excitation if preceded by, followed by, or intermixed with 282 US presentations. The third experiment indicated that in contrast to the decremental effects on excitatory conditioning, inhibitory conditioning was faciliated by large numbers of prior US exposures, suggesting explanation of the post-asymptotic decrement phenomenon by opponent-process theory.

Acoustic Stimulation↗