Publications by authors named "O'Brian J"

Objective: To describe a case of hypocalcemia in a patient with a gain-of-function mutation in the calcium-sensing receptor that was undetected until adulthood and successfully treated with recombinant parathyroid hormone.

Methods: The clinical findings, laboratory data, and a review of the pertinent literature are presented.

Results: A 55-year-old woman was hospitalized and seen by the endocrinology consult service for hypocalcemia that was refractory to repeated doses of intravenous calcium gluconate.

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Pituitary abscess is a rare condition. In the setting of multiple surgical interventions, the risk of its development increases. A 49-year-old man presented with episodes of altered mental status.

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Cardiac calsequestrin concentrates in junctional sarcoplasmic reticulum in heart and skeletal muscle cells by an undefined mechanism. During transit through the secretory pathway, it undergoes an as yet uncharacterized glycosylation and acquires phosphate on CK2-sensitive sites. In this study, we have shown that active calsequestrin phosphorylation occurred in nonmuscle cells as well as muscle cells, reflecting a widespread cellular process.

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Phospholemman (PLM) is a small (72-amino acid) transmembrane protein found in cardiac sarcolemma that is a major substrate for several protein kinases in vivo. Detailed structural data for PLM is lacking, but several studies have described an ion conductance that results from PLM expression in oocytes. Moreover, addition of purified PLM to lipid bilayers generates similar ion currents, suggesting that the PLM molecule itself might be sufficient for channel formation.

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The sequence of a 20.15 kb region from human herpesvirus 6 variant B (HHV-6B) strain Z29 is described (GenBank accession number L14772). Determinations of protein homologies for seventeen predicted gene products revealed HHV-6B homologs of six proteins well-conserved both in genetic context and amino acid sequence throughout the alpha-, beta-, and gammaherpesvirus subfamilies.

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A continuous 20.9 kb sequence from human herpesvirus 6 variant B (HHV-6B) strain Z29 (GenBank accession number L16947) is genetically colinear with a discrete segment of the human cytomegalovirus (HCMV) UL region and with HHV-6 variant A (HHV-6A). Short nucleotide sequence determinations at multiple sites within an 8.

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Although it is clear that gene transfection is a potentially valuable approach in the study of cardiac cell function and differentiation, classic transfection methods are limited by their poor efficiencies in cardiac cells. Recent studies show that recombinant replication-defective human adenovirus can transfect primary cardiac cultures with near 100% efficiency. Since such recombinants are time consuming to prepare, the goal of this study was to develop a plasmid/viral transfection system that would capitalize on the advantages of adenovirus.

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Purpose: The usefulness of transcranial Doppler monitoring in identifying emboli in the arterial circulation has been established. We attempted to extend this technique to identify embolism in the venous circulation and to note any changes in embolism rate with anticoagulation.

Methods: From March to July 1993, 218 patients were evaluated by duplex scan for deep venous thrombosis.

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Human herpesvirus 6(HHV-6) variants A and B differ in cell tropism, reactivity with monoclonal antibodies, restriction endonuclease profiles, and epidemiology. Nonetheless, comparative nucleotide and amino acid sequences from several genes indicate that the viruses are very highly conserved genetically, The B variant is the major etiologic agent of exanthem subitum and is frequently isolated from children with febrile illness; no disease has been etiologically associated with HHV-6A. One HHV-6A strain has been cloned and sequenced, but similar information and reagents are not available for HHV-6B.

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Phospholemman (PLM) is a 72-amino-acid peptide with a single transmembrane domain, the expression of which induces chloride currents in Xenopus oocytes. It has remained unknown whether PLM is an ion channel or acts as a channel regulator. Here we show, by measuring unitary anion currents across planar phospholipid bilayers to which immunoaffinity-purified recombinant PLM was added, that it does indeed form ion channels.

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Phospholamban (PLB) is a small, transmembrane protein that resides in the cardiac sarcoplasmic reticulum (SR) and regulates the activity of Ca(2+)-ATPase in response to beta-adrenergic stimulation. We have used the baculovirus expression system in Sf21 cells to express milligram quantities of wild-type PLB. After purification by antibody affinity chromatography, the function of this recombinant PLB was tested by reconstitution with Ca(2+)-ATPase purified from skeletal SR.

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Such problems as sexually transmitted diseases, alcohol and other drug use, and acquaintance rape require college health professionals to function in primary and secondary preventive roles. In this article, the authors draw upon counseling literature and college health practice to identify the central elements of preventive programs, highlight specific intervention formats used in preventive work, and describe how interventions are assembled into coherent programs of prevention. To illustrate the structure and process of long-range, institutionalized preventive efforts, the authors describe an initiative addressing the primary, secondary, and tertiary prevention of substance use at a health sciences campus.

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The etiology of incidentally discovered, nonfunctional adrenal nodules was evaluated by using the 17-hydroxyprogesterone (17-OHP) response to synthetic adrenocorticotrophin (cosyntropin) (ACTH) administration. Patients who were discovered to have adrenal nodules and age-matched volunteers were studied. A total of 12 patients with adrenal nodules and 10 control subjects were studied.

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The infectious laryngotracheitis virus (ILTV) homologue of the herpes simplex virus type 1 (HSV-1) glycoprotein B (gB) gene was identified by PCR amplification of genomic ILTV DNA. A 488-bp amplified DNA fragment was used to identify and clone two adjacent PstI fragments from genomic ILTV DNA. Sequence analysis of the region surrounding the amplified fragment identified a 2619-bp open reading frame that has 39% homology with both the nucleotide and amino-acid sequences of the HSV-1 gB gene.

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Recent enhanced attention to diabetic foot infection--in both clinical care and research--has yielded a modified picture of this disorder. It suggests that certain diabetic patients may have important risk factors for the development of infection, and further, infections in these patients may not have the same clinical characteristics as the soft tissue or bony infections found in nondiabetic subjects. Treatment of diabetic patients should therefore be modified to conform to the particular characteristics of their infections.

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Ventricular tachycardia in patients with phenochromocytoma is rare. We report a patient with a norepinephrine-secreting extra-adrenal pheochromocytoma who had exercise induced ventricular tachycardia. Prior to diagnosis, the patient was treated with a selective beta 1 blocker, atenolol, which resulted in suppression of the dysrhythmia and amelioration of the hypertension.

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We investigated the effects of Antarctic residence (AR) on serum thyroid hormone and cardiovascular responses to a 60-min standard cold air (0 degree C) test (SCAT). Serum total thyroxine (TT4) and serum total triiodothyronine (TT3), free T4 (FT4) and T3 (FT3), thyrotropin (TSH), and percent free fraction of T4 (%FT4) and T3 (%FT3) were measured in normal men (n = 15) before and after each of three SCATs. The SCAT was first carried out in California and then repeated after 24 and 44 wk AR.

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Humans who live in Antarctica for greater than 5 continuous months demonstrate alterations in the hypothalamic-pituitary-thyroid axis. These changes are characterized by 1) increased pituitary release of TSH in response to iv TRH, 2) increased serum clearance of orally administered T3, and 3) normal serum total, free T4, and unstimulated TSH levels. To clarify the mechanism responsible for these findings, serum kinetic studies of 125I-labeled T4 and T3 were carried out in a group of normal men, first in California, then after 20 and 42 weeks of continuous Antarctic residence.

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Partially purified extracts from Chlorella pyrenoidosa and Chlamydomonas reinhardtii catalyze the cleavage of queuosine (Q), a modified 7-deazaguanine nucleoside found exclusively in the first position of the anticodon of certain tRNAs, to queuine, the base of Q. This is the first report of an enzyme that specifically cleaves a 7-deazapurine riboside. Guanosine is not a substrate for this activity, nor is the epoxide a derivative of Q.

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Very little is known regarding hormonal adaptation in human subjects who are exposed to the extremes of temperature and light that are found in polar latitudes. We have previously reported a 50% elevation in the serum thyrotropin (TSH) response to thyrotropin-releasing hormone (TRH), a fall in serum total triiodothyronine (T3) and free T3 (fT3), and no change in serum total thyroxine (T4) or free T4 (fT4) after 42 wk of Antarctic cold exposure. To differentiate between central and peripheral mechanisms that may lead to these changes, we report the effect of sequentially increasing oral doses of T3 (Cytomel) on serum T3 and fT3 levels and on the resultant attenuation of the TSH response to TRH in nine men before, during, and after 42 wk residence in Antarctica.

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The effects of a number of commonly used skin refrigerants were studied in controlled freezing experiments on guinea pig skin. Frigiderm and Fluro Ethyl produced very little effect on the skin compared to colder preparations such as Cryosthesia -30 degrees C and Cryosthesia -60 degrees C.

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Short-term fasting in humans is associated with diminished delta TSH to TRH. The purposes of the present study were to reassess basal TSH levels and TRH responsiveness during fasting utilizing a sensitive radioimmunoassay (RIA: sensitivity 0.3 microU/ml; normal range 0.

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