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Biomedical subjects

L Hopp

Publications and source records attributed to L Hopp.

At least 19 recordsLinked to original sources
PubMed2001

Amphotericin B-induced partial nephrogenic diabetes insipidus in a child.

The case of a 12-year-old boy who developed polyuria and polydipsia while on amphotericin B treatment is discussed. The clinical and laboratory features are most consistent with partial nephrogenic diabetes insipidus. Several adult patients have been reported with amphotericin B-induced nephrogenic diabetes insipidus. To the knowledge of the authors, this is the first pediatric patient described with this condition. Pharmacological doses of antidiuretic hormone in conjunction with diuretic treatment significantly reduced the polyuria and alleviated the associated symptoms. The authors propose that in amphotericin B-induced partial nephrogenic diabetes insipidus, pharmacological doses of antidiuretic hormone may offer an additional benefit to commonly used diuretic therapy.

Amphotericin B↗
PubMed1999

Hypercalciuria and urolithiasis in a case of Costello syndrome.

Costello syndrome is characterized by postnatal growth deficiency, mental retardation, curly hair, coarse characteristic face, and loose skin of hands and feet. Patients with this syndrome have a high incidence of cardiac involvement, including arrhythmia, atrial septal defect, and hypertrophic cardiomyopathy. We report a 16-year-old adolescent female with Costello syndrome who presents with hypercalciuria and urolithiasis.

Abnormalities, Multiple↗
PubMed1999

Angiotensin converting enzyme inhibitor-induced angioedema: a report of two cases.

Angioedema is a rare but potentially fatal side effect of angiotensin converting enzyme (ACE) inhibitors. We report for the first time, two children with systemic lupus erythematosus who developed acute angioedema after the long-term use of enalapril. Prompt recognition and appropriate management of ACE-induced angioedema prevented life-threatening complications. This report highlights the potential risks of angioedema associated with the use of ACE inhibitors in children. Patients should be advised to seek medical treatment immediately if they experience swelling of the face, neck, or tongue, and especially if they have trouble breathing, speaking, or swallowing.

Adolescent↗
PubMed1998

Bisphenols that stimulate cells to release alkali metal cations: a structure-activity study.

The laxative action of phenolphthalein (5) is believed to result from induction of potassium and water efflux from the colon epithelium. In cultured cells, K+ efflux is promoted by 5 and by a contaminant (1) present in commercial phenol red. Six compounds with chemical structures related to those of 5 and 1 were tested for ability to induce the release of 86Rb from COS-7 cells preloaded with this isotope: 4,4'-(9-fluorenylidene)diphenol (2), 4, 4'-(9-fluorenylidene)dianiline, 4, 4'-(9-fluorenylidene)bisphenoxyethanol, 1,1'-bi-2-naphthol, 4, 4'-biphenol, and bis(4-hydroxyphenyl)methane. With one exception these compounds were all inactive at a concentration of 10 microM. However, 2 caused profound 86Rb efflux at concentrations as low as 100 nM. Concentrations of 5 1-2 orders of magnitude higher were needed to achieve similar levels of activity. The three compounds known to be active in this experimental system share a common feature that is absent in all the inactive compounds: a five-membered ring structure, one of whose carbon atoms is disubstituted with p-hydroxyphenyl residues. Because 2 and 5 are readily available, comparative studies on the mechanism of action of these biphenols at the cellular level can now be undertaken.

Animals↗
PubMed1998

Severe cardiac dysrhythmia in patients using bromocriptine postpartum.

Used worldwide since 1980 for the prevention of breast engorgement in the puerperium, in 1994 bromocriptine mesylate was withdrawn from the American market as an agent suitable for ablactation. The relevant recommendation of the Food and Drug Administration rested on case reports that described severe vasospastic reactions among users of the drug. Some patients so affected suffered stroke, intracranial bleeding, cerebral edema, convulsions, myocardial infarction, and puerperal psychosis. More recently, it has been suggested that the side effects of the drug may also include circulatory collapse secondary to cardiac dysrhythmia. This report describes two additional cases in this category. The antepartum clinical evaluation of these women suggested that they were predisposed to arrhythmias.

Adult↗
PubMed1997

Lack of difference in oxalate-dependent Ca2+ uptake by membrane homogenate of African-American and white subjects.

In order to further characterize previously described racial differences in intracellular Ca2+ homeostasis, the activity of sarcoplasmic-endoplasmic reticulum Ca2+-ATPase was measured in cultured skin fibroblasts from normotensive African-Americans and whites. Cells originated from apparently healthy, normotensive African-American (n = 15) and white (n = 15) subjects. The activity of the sarcoplasmic-endoplasmic reticulum Ca2+-ATPase was measured by: 1) oxalate-dependent only, and 2) oxalate-dependent, thapsigargin-sensitive 45Ca2+ uptake of membrane homogenates. Over 90% of the oxalate-dependent 45Ca2+ uptake was thapsigargin-sensitive. There was no detectable racial difference in the sarcoplasmic-endoplasmic reticulum Ca2+-ATPase activity with either technique. It is concluded that the previously described higher cellular Ca2+ turnover and larger cellular stores of exchangeable Ca2+ in cells from African-Americans versus whites are not due to changes in the sarcoplasmic-endoplasmic reticulum Ca2+-ATPase itself. The findings do not exclude possible increased activity of this enzyme in intact cells of African-Americans where regulatory mechanisms not present in the membrane preparation may operate.

Black People↗
PubMed1997

Linkage analysis using platelet-activating factor Ca2+ response in transformed lymphoblasts.

Epstein-Barr virus-transformed lymphoblasts from patients with essential hypertension demonstrate enhanced G protein-mediated cytosolic free calcium ([Ca2+]i) response to platelet-activating factor (PAF). To map genes responsible for variation in G protein-coupled signaling, we used this cellular phenotype for a linkage study of transformed cell lines from the Centre d'Etude du Polymorphisme Humain (CEPH) reference pedigrees. The PAF-evoked change in [Ca2+]i ranged from 20 to 392 mmol/L and was highly reproducible within each cell line. PAF-elicited [Ca2+]i responses were obtained in lymphoblastic cell lines from five densely mapped pedigrees of the CEPH collection. Using PAF-evoked [Ca2+]i responses as a quantitative trait, two-point sibpair linkage analyses were conducted using 5150 markers from the Collaborative Human Linkage Center (CHLC) database. Nine loci, located on chromosomes 1, 4, 10, 11, 13, 16, and 17, were suggestive of linkage, with values of P < 7.4 x 10(-4). Multipoint linkage analysis produced a significant linkage finding (P = 2.1 x 10(-5) in one family at D16S151, with suggestive linkage results for seven additional markers spanning a 40-cM interval of chromosome 16. Multipoint analysis produced suggestive findings of linkage to eight loci from two distinct regions of chromosome 11 in another family. These results indicate that loci involved in the control of G protein-mediated mechanisms, suggested to be involved in the pathophysiology of essential hypertension, can be identified using cell lines from general pedigrees selected without any knowledge of the blood pressure status of the donors. This strategy represents an approach to rapidly and inexpensively mapping loci related to common, complex disorders, using phenotypes that are stable in immortalized lymphoblasts together with existing reference pedigree cell lines and genotype databases.

B-Lymphocyte Subsets↗
PubMed1996

Myocardial infarction postpartum in patients taking bromocriptine for the prevention of breast engorgement.

Three cases of myocardial infarction (MI) in women taking bromocriptine for milk suppression are presented. The incidents occurred in 1993 and 1994, the last only two weeks before the withdrawal of the drug from the American market as a drug suitable for ablactation. In one patient, the MI presented on the 12 day postpartum and was accompanied by signs and symptoms reminiscent to ergotism. Another mother suffered MI, accompanied by hypertension, six days after a vaginal delivery complicated by postpartum haemorrhage. The third patient began to take bromocriptine more than 2 weeks postpartum and died suddenly 24 days after her childbirth. To the knowledge of the authors, these are the 12th to 14th literary reports describing an apparent association between the use of bromocriptine for ablactation and the occurrence of MI in the puerperium.

Adult↗
PubMed1996

Evidence for amelioration of endothelial cell dysfunction by erythropoietin therapy in predialysis patients.

Evidence for the involvement of endothelial cells in the pathogenesis or erythropoietin-induced hypertension, and for endothelial cell damage in patients with chronic renal failure, has emerged and appears to be of major concern. We, therefore, investigated the effect of recombinant human erythropoietin (rHuEPO) therapy on endothelium-derived hormones in predialysis patients with progressive renal anemia. At the entry to the trial, the serum thrombomodulin concentration (Tm) and plasma endothelin-1 concentration (ET-1) in the predialysis patients were significantly higher than those in age- and sex-matched normal subjects. Following a 16 week period of treatment with 6000IU rHuEPO given intravenously once a week, patients' hematocrit increased from 27.1 +/- 2.6% to 34.6 +/- 3.2% (n = 16, P < .001). A positive correlation was found between Tm and serum creatinine concentration (Cr) (r = 0.61, P < .05 (n = 16), but no correlation was found between ET-1 and Cr. Tm and Tm/Cr significantly decreased from 7.9 +/- 2.8 ng/mL to 6.6 +/- 2.4 ng/mL (P < .01, n = 16), and from 2.1 +/- 0.7 (x10(-10) to 1.6 +/- 0.7 (x10(-10), P < .01, n = 16), respectively. However, there was no change in ET-1 as a result of the rHuEPO therapy. Creatinine clearance (Ccr), Cr, total amount of daily Tm excretion, Tm clearance/Ccr, daily urinary protein and albumin excretion, and blood pressure also remained unchanged throughout the trail. The present study indicates that correcting anemia by rHuEPO therapy reduces an abnormally elevated Tm in predialysis patients while blood pressure and renal function remain unchanged, suggesting that rHuEPO has a beneficial effect on endothelial cell dysfunction in chronic renal failure patients. This effect may be mediated via an improved oxygen supply to the endothelial cells due to the amelioration of anemia by rHuEPO.

Adult↗
PubMed1996

Acute myocardial infarction in a healthy mother using bromocriptine for milk suppression.

A 34-year-old mother developed acute myocardial infarction (MI) 10 days postpartum while taking bromocriptine for ablactation. Her only known risk factor was moderate hypercholesterolemia. The initial coronary arteriogram revealed minimal irregularities of the mid- and distal left anterior descending (LAD) artery, but severe narrowing of a large first diagonal branch of the LAD. Repeat coronary arteriography, performed two months later for recurrent chest pain, showed no significant change in the LAD. There was, however, a marked improvement in the first diagonal branch. To the authors' knowledge this is the 10th report of MI in a patient using bromocriptine postpartum for milk suppression and only the second one to implicate by its investigations the role of vasospasm in the coronary vessels at the cause of the infarction.

Adult↗
PubMed1996

Bromocriptine related atypical vascular accidents postpartum identified through medicolegal reviews.

Recent literary case reports indicate that bromocriptine mesylate, when used for the suppression of lactation in the puerperium, can cause serious and even lethal side effects. The untoward sequelae are attributed to generalized or focal vasospasm affecting the cardiac and/or cerebral bold vessels. Apart from pre-existing hypertension and use in association with other ergot derivatives, the factors predisposing to such complications have not been elucidated, The authors present three atypical bromocriptine related postpartum accidents which may expand the understanding both of the predisposing factors and the potential consequences of bromocriptine related severe side effects. One of the cases raises the suspicion that the manifestations of hyperthyroidism may be aggravated by this method of pharmacologic ablactation. Another observation appears to imply that the drug may trigger the onset of chronic hypertension in women so predisposed. The development of cerebral infarcts, identified by MRI, in a clinically asymptomatic woman, exemplifies the threat of recurrent seizure activity in cases of bromocriptine related stroke.

Adult↗
PubMed1995

FK506 in pediatric kidney transplantation--primary and rescue experience.

Between 14 December 1989 and 17 December 1993, 43 patients undergoing kidney transplantation alone at the Children's Hospital of Pittsburgh received FK506 as the primary immunosuppressive agent. The mean recipient age was 10.2 +/- 4.8 years (range 0.7-17.4 years), with 7 (16%) children under 5 years of age and 2 (5%) under 2 years of age. Fifteen (35%) children underwent retransplantation, and 5 (12%) had a panel-reactive antibody level greater than 40%. Twenty-two (51%) transplants were with cadaveric donors and 21 (49%) were with living donors. The mean follow-up was 25 +/- 14 months; there were no deaths; 1- and 3-year actuarial graft survival was 98% and 85%. The mean serum creatinine and blood urea nitrogen were 1.2 +/- 0.6 mg/dl and 26 +/- 11 mg/dl; the calculated creatinine clearance was 75 +/- 23 ml/min per 1.73 m2. Twenty-four (62%) patients have been successfully withdrawn from steroids and 24 (62%) require no anti-hypertensive medication. Improved growth was seen, particularly in pre-adolescent children off steroids. Between 28 July 1990 and 2 December 1993, 24 children were referred for rescue therapy with FK506, 14.6 +/- 16.4 months (range 1.1-53.2 months) after transplantation. Nineteen (79%) were referred because of resistant rejection; 4 (17%) were referred because of proteinuria; 1 (4%) was switched because of steroid-related obesity. There were no deaths; 1- and 2-year graft survival was 75% and 68%; 17 (71%) patients were successfully rescued, including 1 of 2 patients who arrived on dialysis; 4 (24%) of the successfully rescued patients were weaned off steroids.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Quinine sensitive changes in cellular Na+ and K+ homeostasis of COS-7 cells caused by a lipophilic phenol red impurity.

An impurity of phenol red (PRI) has been shown to markedly alter the intracellular Na+ and K+ homeostasis of several cell types. The effect of PRI seems to involve intracellular Ca(++)-dependent mechanisms. Using COS-7 cells as a model, we further characterized the mechanism of action of PRI by measuring cellular Na+/K+ contents and 86Rb+ efflux. Similar to human skin fibroblasts, in COS-7 cells calmodulin inhibition moderated the cationic transport effects of PRI. A TMB-8 dependent intracellular Ca++ pool does not seem to be involved in these transport events. We found no evidence for participation of the transcriptional-translational machinery in the effect of PRI. Both quinine and quinidine are able to prevent nearly all changes caused by PRI in the cellular Na+/K+ contents and 86Rb+ efflux. Although phenol red contained multiple impurities by high performance liquid chromatography (HPLC), phenolphthalein, a structurally close relative of phenol red, was free of any detectable contamination. Phenolphthalein elicited qualitatively similar transport changes to those observed during exposure to PRI. Regardless of the exact mechanism of action, we propose that the as yet unidentified substance is not a cellular toxin, rather it is a cationic transport modulator. Directly or indirectly, it may interact with the cellular Ca++/calmodulin system and activate some quinine/quinidine sensitive transport processes. This transport process is likely to be a Ca(++)-sensitive K+ channel but, due to the lack of specificity of quinine and quinidine, other transport mechanisms must be also considered. The chemical nature of PRI may be similar to phenolphthalein.

Animals↗
PubMed1995

Low-dose intraocular tissue plasminogen activator treatment for traumatic total hyphema, postcataract, and penetrating keratoplasty fibrinous membranes.

Tissue plasminogen activator (tPA) has been used to treat severe postcataract and vitrectomy fibrinous membranes, but intraocular bleeding has occurred with doses of 25 micrograms or higher. We report three patients, one with nonclearing total hyphema and uncontrollable intraocular pressure and two with severe fibrinous membrane formation, who had treatment with low-dose (4 micrograms to 6 micrograms) intraocular tPA. Although the fibrinous membranes or hyphema resolved in all three patients, they recurred and bleeding that required additional treatment occurred in one patient. Intraocular low-dose tPA may minimize the risk of corneal and retinal toxicity and may be considered an alternative treatment in intractable cases. However, secondary intraocular hemorrhage can occur, and the timing between the initial vascular injury, treatment with tPA, and subsequent bleeding may reduce the risk of further hemorrhaging.

Adult↗
PubMed1994

Comparison of FK-506 and cyclosporine regimens in pediatric renal transplantation.

Clinical aspects of FK-506 or cyclosporine immunosuppression regimens were evaluated in 48 consecutive pediatric renal transplant recipients. Tapering and discontinuation of prednisone was employed only in children receiving FK-506 who experienced minor or no rejection episodes during the 1st posttransplant month. At 1 year follow-up, 17 of 22 (77%) of all children with functioning allografts were receiving no prednisone (n = 13) or a mean dosage of 0.07 mg/kg per day (n = 4). During the 1st month, acute cellular rejection was more common in the FK-506 group (0.58 vs. 0.21 rejections per patient, P < 0.05) but allograft survival (92%) and renal function at 1 year posttransplant were identical in both groups. Compared with the cyclosporine regimen, FK-506 immunosuppression may be associated with a higher incidence of cytomegalovirus or reversible Epstein-Barr virus-induced lymphoproliferative disease. However, the FK-506 group had less hirsutism and gingival hypertrophy and required fewer antihypertensive medications independent of steroid use. Height standard deviation scores and weight-for-height index improved only in pre-adolescents receiving FK-506 but no prednisone (P < 0.02 and P < 0.05, respectively), but did not differ between children on FK-506 plus prednisone and those in the cyclosporine group. We conclude that the major advantages of FK-506 over cyclosporine immunosuppression are a reduced severity of hypertension and an improved cosmetic appearance which may improve long-term medical compliance. When used as monotherapy, FK-506 also shows promise in relieving the growth retardation associated with cyclosporine regimens that include prednisone.

Adolescent↗