Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The alpha 2-macroglobulin (alpha 2M) receptor complex as purified by affinity chromatography contains three polypeptides: a 515-kDa heavy chain, an 85-kDa light chain, and a 39-kDa associated protein. Previous studies have established that the 515/85-kDa components are derived from a 600-kDa precursor whose complete sequence has been determined by cDNA cloning (Herz, J., Hamann, U., Rogne, S., Myklebost, O., Gassepohl, H., and Stanley, K. (1988) EMBO J. 7,4119-4127). We have now determined the primary structure of the human 39-kDa polypeptide, termed alpha 2M receptor-associated protein, by cDNA cloning. The deduced amino acid sequence contains a putative signal sequence that precedes the 323-residue mature protein. Comparative sequence analysis revealed that alpha 2M receptor-associated protein has 73% identity with a rat protein reported to be a pathogenic domain of Heymann nephritis antigen gp 330 and 77% identity to a mouse heparin-binding protein termed HBP-44. The high overall identity suggests that these molecules are interspecies homologues and indicates that the pathogenic domain, previously thought to be a portion of gp 330, is in fact a distinct protein. Further, the 120-residue carboxyl-terminal region of alpha 2M receptor-associated protein has 26% identity with a region of apolipoprotein E containing the low density lipoprotein receptor binding domain. Pulse-chase experiments revealed that the newly formed alpha 2M receptor-associated protein remains cell-associated, while surface labeling experiments followed by immunoprecipitation suggest that this protein is present on the cell surface forming a complex with the alpha 2M receptor heavy and light chains.
 ...
PMID:Primary structure of alpha 2-macroglobulin receptor-associated protein. Human homologue of a Heymann nephritis antigen. 171 82

Advances in biomedical technology have contributed effectively to the resolution of basic and clinical problems in Nephrology. Most of our insights on glomerular diseases come from animal models. Antibodies against components of the extracellular matrix have been shown to induce glomerular changes in vivo and the non-collagenous NC1 domain of type IV collagen has been demonstrated to contain the Goodpasture antigen. New pathogenetic mechanisms of glomerular injury are suggested by studies on the interaction of antibodies with glomerular cell surface antigens. Gp330, a glycoprotein expressed at the surface of glomerular visceral epithelial cells, has been recognized to be the most relevant antigen of Heymann nephritis. Antibodies able to crosslink gp330 bind to the antigen at the base of foot processes and the resulting immune complexes are shed into the subepithelial space where they form electron dense deposits. The complement membrane attack complex (C5b-9) is likely to be directly responsible for epithelial cell injury and proteinuria in this model. Other cell surface antigens of the glomerular capillary wall, such as dipeptidyl dipeptidase IV, podocalyxin, podoendin, have been characterized. A novel model of glomerular injury comes from the demonstration that a non-complement fixing monoclonal antibody to a surface sialo-glycoprotein (SGP-115/107) binds to glomerular visceral epithelial cells and causes morphological changes which appear epitope-specific and complement and leukocyte-independent. The mechanisms responsible for the progression of renal disease to glomerular sclerosis have been extensively explored in the last years. Among the hemodynamic factors intraglomerular hypertension has been established to play an important part, at least in some models.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:[Nephrology]. 269 52

The renal glomeruli are vulnerable to injury by a number of drugs and other toxic agents. These agents may lead to damage by one of two basic mechanisms: direct, dose-related toxic injury; indirect, immunologically mediated injury, largely dose-independent. Proteinuria is the simplest and most important functional indicator of glomerular injury. It occurs almost immediately in direct toxic injury, but there is a latent period of weeks to months with immunologically mediated processes. Of the two mechanisms, the second is by far the more common in clinical settings. The best studied experimental agent causing direct toxic injury is the aminonucleoside of puromycin. Clinically, perhaps the most important agent is Cyclosporine A. Although this agent is usually thought of primarily as a tubular toxin, it is capable of giving rise to a microangiopathic glomerular lesion similar to that in the hemolytic uremic syndrome. The classic model for immunologic glomerular lesion is Heymann nephritis, which produces a membranous glomerulopathy. Clinically, most drug mediated glomerulopathies also take the form of a membranous nephropathy, usually with a frank nephrotic syndrome. Among the more common offenders are penicillamine, gold salts used in rheumatoid arthritis, and captopril used in hypertension. The other common type of drug-related glomerulopathy occurs as part of a lupus-like syndrome induced by a variety of drugs, including hydralazine, procainamide, and penicillamine. All of these give rise to a variety of antibodies, most prominently antinuclear antibodies, and in the more severe cases there may be lupus-like glomerular lesions as well.
 ...
PMID:Drug-associated glomerulopathies. 294 Jun 67

1. Normal rats and passive Heymann membranous glomerulonephritic rats were chronically treated with DOCA/NaCl for 9 weeks. Normal and untreated nephritic rats were used as controls. Urinary kallikrein excretion (UKE), proteinuria and tail blood pressure (BP) were determined in awake rats. Glomerular filtration rate (GFR), plasma renin activity (PRA), and plasma potassium (PK) concentration were measured at the end of the experiment. 2. Comparison between basal and 9th-week measurements indicated that DOCA/NaCl administration significantly increased (P less than 0.05) UKE (3.96 +/- 0.30 vs 7.60 +/- 1.51 U/24 h) and BP (118 +/- 2 vs 135 +/- 6 mmHg) in normal rats, whereas in nephritic DOCA/NaCl-treated rats, UKE was unaltered (3.80 +/- 0.50 vs 3.40 +/- 0.30 U/24 h) and BP increased to higher levels (117 +/- 2 vs 152 +/- 3 mmHg) than in the normal DOCA/NaCl group (P less than 0.05). Passive Heymann nephritis alone did not affect UKE (3.56 +/- 0.40 vs 3.60 +/- 0.80 U/24 h) or BP (124 +/- 2 vs 125 +/- 2 mmHg). 3. At the end of the study, PK was decreased and PRA totally suppressed in both normal and nephritic DOCA/NaCl-treated rats. Proteinuria was more pronounced in nephritic DOCA/NaCl-treated rats (44.8 +/- 5.2 mg/day) than in control nephritic animals (15.1 +/- 2.4 mg/day) and GFR was increased equally in both DOCA/NaCl-treated groups. 4. The failure of nephritic rats to respond to DOCA/NaCl by increasing UKE was not associated with any significant derangement of renal function or structure and may have been related to the aggravation of arterial hypertension in this group.
 ...
PMID:Nephritis blunts urinary kallikrein excretion and aggravates DOCA/NaCl hypertension in rats. 324 40

In glomerulonephritic and normal kidneys hypertension has been shown to increase the urinary protein excretion and the thickness of the glomerular basement membrane and to reduce the glomerular filtration rate. We have studied the effect of desoxycorticosterone acetate (DOCA)-salt hypertension on the glomerular anatomy and function in normal control rats and rats with passive Heymann nephritis. Standard methods for measurements of glomerular filtration rate and urinary protein excretion were used and the results were correlated to morphometrical measurements in randomly selected glomeruli in all groups. In control rats, DOCA-salt hypertension increased the kidney weight (P less than 0.001), the glomerular volume (P less than 0.05), and the surface of peripheral glomerular basement membrane (P less than 0.01). The thickness of peripheral glomerular basement membrane and the length of glomerulary capillaries were not affected. In glomerulonephritic rats, DOCA-salt hypertension did not change the kidney weight and glomerular capillary diameter. The thickness of the peripheral basement membrane increased (P less than 0.05), while the length of glomerular capillaries and the surface of peripheral basement membrane were reduced (P less than 0.05). Glomerular filtration rate per unit peripheral basement membrane was not significantly different among the groups while protein excretion per unit peripheral basement membrane increased significantly both in the hypertensive and in the glomerulonephritic groups. The estimated hydraulic conductivity of the glomerular capillaries was reduced both in rats with DOCA-salt hypertension and glomerulonephritic rats with and without DOCA-salt hypertension. In conclusion, DOCA-salt hypertension seems to decrease hydraulic conductivity and increase protein excretion both in normal and in glomerulonephritic kidneys although the effect on glomerular morphology is different.
 ...
PMID:The effect of hypertension on glomerular structures and capillary permeability in passive Heymann glomerulonephritis. 367 Jan 11

Hypertension has been shown to accelerate the course of experimental nephritis. On the other hand, Heymann nephritic rats undergoing long-term DOCA-NaCl treatment develop hypertension with a malignant course. The present study examined the effect of a short-term DOCA-NaCl load on the development of hypertension and progression of nephritis. Heymann nephritic rats were treated with DOCA-NaCl between weeks 2 and 6 after the first immunization with brush border antigen. Within six weeks, hypertension developed in Heymann nephritis-DOCA-NaCl rats but not in Heymann nephritic rats without DOCA-NaCl treatment whereas DOCA-NaCl-treated rats developed a moderate elevation of blood pressure. During that time, anti-brush border antibodies and immune deposits typical of membranous nephropathy ensued, preceding appearance of proteinuria or histopathologically detectable renal changes in the immunized rats. After discontinuation of DOCA-NaCl treatments at week 6, blood pressure nearly normalized in DOCA-NaCl-treated rats. Within one year, however, blood pressure rose most markedly in nephritic rats treated initially with DOCA-NaCl. The rise in blood pressure at that time correlated with glomerular sclerosis, tubulo-interstitial changes and proteinuria. It is concluded that, during acute nephritis, immunological and hypertensinogenic mechanisms interact, leading to hypertension and aggravated course of nephritis. These experimental observations on nephritis-associated hypertension may have important bearings on human hypertension as well.
 ...
PMID:Hypertension and progression of experimental nephritis. Interaction between immunological and haemodynamic factors. 391 83

In order to determine the influence of hypertension on the progression of chronic glomerulonephritis, we studied the renal lesions in Heymann nephritis (autologous immune complex nephritis) produced in SHR. Nephritic SHR treated by AHD, normal SHR, nephritic WKYR, and normal WKYR served as controls. Induction of Heymann nephritis did not alter the blood pressure in either SHR or WKYR as compared with each untreated control group. Administration of AHD normalized the blood pressure of SHR. Proteinuria, hypoproteinemia, hypercholesterolemia, and reduction in body weight were significantly greater in nephritic SHR than in nephritic SHR treated by AHD or nephritic WKYR, whereas BUN and serum creatinine were unchanged in all the nephritic rats. Histological findings such as glomerular basement membrane thickening, IgG and C3 deposits along capillary walls, and subepithelial electron-dense deposits were similar in all nephritic groups. Glomerular sclerosis and tubulointerstitial changes were more marked in nephritic SHR than in the other nephritic groups. Severe vascular thickening and necrosis, intravascular thrombosis, and perivascular cell infiltration were frequently observed in nephritic SHR. These lesions are characteristic of malignant hypertension. However, they were not found in control SHR, which maintained elevation of blood pressure equivalent to that of nephritic SHR throughout the study. It was concluded that hypertension may aggravate nephritic manifestations such as proteinuria, hypoproteinemia, and hypercholesterolemia but not excretory renal function and that the hypertensive vascular lesions are augmented by Heymann nephritis.
 ...
PMID:Influence of hypertension on the progression of experimental autologous immune complex nephritis. 621 70

Heymann nephritis was induced in rats with spontaneous hypertension (group HN), and renal lesions were investigated at the twentieth and thirty-sixth week. An identical group given antihypertensive drugs (group HN-AH), an identical group given anticoagulant drugs (group HN-AC), and a nonimmunized control group of spontaneously hypertensive rats (controls) were also examined. Massive proteinuria, hypoalbuminemia, and hyperlipidemia were present in groups with induced Heymann nephritis (HN, HN-AH, and HN-AC). Coagulation studies demonstrated a shortening of prothrombin time, an increase in serum fibrinogen and thrombocytes, and a reduction of antithrombin III in the groups HN and HN-AH. Necrotizing lesions were observed only in group HN and without further elevation in blood pressure. Intravascular thrombosis was prominent at the twentieth week, and marked fibrinoid necrosis appeared at the thirty-sixth week. These vascular lesions were not observed in the HN-AH, HN-AC, and control groups. Thus, a state of hypercoagulability in addition to high blood pressure probably contributes to the genesis of necrotizing vascular lesions in spontaneously hypertensive rats with nephritis.
 ...
PMID:Necrotizing vascular lesions in spontaneously hypertensive rats with nephrotic syndrome: hypercoagulability as a contributory factor. 638 12

In order to explore immunological features of hypertension, we studied autologous immune complex nephritis (Heymann nephritis) combined with DOCA-NaCl treatment. This combination resulted in hypertension and increased heart weight whereas DOCA-NaCl treatment alone induced only a slight elevation of blood pressure and a moderate increase in heart weight. Nephritic rats without DOCA-NaCl load remained normotensive, their heart weights being comparable to those of controls. This new model of hypertension was neither characterized by azotemia nor by reduced renal excretory capacity. Hypertension was not renin-angiotensin-dependent. DOCA-NaCl treatment accelerated the development of proteinuria. In the hypertensive rats, systolic blood pressure to daily urinary protein excretion. Renal histopathology revealed changes resembling those of malignant nephrosclerosis. Immunohistology and electron microscopy showed a typical membranous glomerulonephritis in all immunized animals. It was concluded that immune complex disease of the Heymann nephritis type may interfere with normal hemodynamic adaptation to hypervolemic sodium load, resulting in hypertension.
 ...
PMID:Autologous immune complex nephritis and DOCA-NaCl load: a new model of hypertension. 644 27

Captopril (SQ 14225) had a clear antihypertensive effect in rat Heymann nephritis-DOCA-NaCl hypertension, a low renin model introduced recently, but was ineffective in 1-kidney-DOCA-NaCl hypertension although plasma renin activity (PRA) was suppressed similarly in both. Thus, the antihypertensive effect of captopril was independent of circulating renin. This result also suggests different pathogenetic mechanisms of hypertension in these two DOCA-NaCl models.
 ...
PMID:Efficacy of captopril in experimental low renin hypertension. 700 65


1 2 Next >>