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PubMed1991

Toxicity of rapamycin--a comparative and combination study with cyclosporine at immunotherapeutic dosage in the rat.

Sprague-Dawley rats were treated for 14 days with rapamycin (RAP; 1.5 mg/kg/day i.p.), cyclosporine (15 mg/kg/day by gavage), both drugs in combination, or appropriate drug vehicles. Hematological parameters and biochemical indices of renal and hepatic function were determined throughout the experimental period, at the end of which the rats were killed and tissues examined histologically. There was a significant reduction in weight gain in RAP- but not CsA-treated animals, while rats given both drugs showed a reduction in body weight over the 14-day experimental period. There were no significant alterations in absolute or differential white blood cell counts or in T or B cell numbers, except in the drug combination group, in which an absolute lymphopenia was detected on day 14. Small but significant increases in urinary flow rate (UFR) were found with either drug alone, and there was a marked (4-fold) increase in UFR in response to drug combination. Both RAP and CsA caused a small elevation in serum creatinine concentrations, but only with CsA was there a significant elevation in urinary enzyme activity and reduction in 51Cr. EDTA clearance. The drug combination exacerbated renal impairment, the extent of which was greater than the additive effect of either drug alone. Hyperbilirubinemia of similar magnitude was observed in rats receiving either CsA alone or in combination with RAP. In contrast to its effect on renal function, however, the CsA+RAP combination was without additional effect on liver function compared with the minor changes seen with either drug alone. Plasma and urinary glucose levels were elevated in all drug treatment groups and especially in animals given both drugs. RAP administration did not significantly affect whole-blood CsA concentrations, although the possibility of a pharmacokinetic interaction cannot be totally excluded. Histological studies revealed striking thymic medullary atrophy in all drug-treated animals. In addition, all rats given RAP showed focal myocardial necrosis of overall mild-moderate severity. Kidneys of RAP-treated rats appeared normal, whereas mild, focal, acute tubular necrosis was evident in all CsA-treated animals. Pancreases of all drug-treated animals were normal.

Animals↗

PubMed1992

Interatrial pressure difference during inflation of pneumatic antishock garments and positive end-expiratory pressure ventilation.

Since an increase in the right atrial pressure (RAP) above the left atrial pressure (LAP) may then lead to paradoxical air embolism, the efficacy of pneumatic antishock garments (PASGs) and ventilation with positive end-expiratory pressure (PEEP) in preventing increases in the RAP above the LAP was investigated during neurosurgical procedures. We examined the RAP and pulmonary capillary wedge pressure (PCWP) of 25 patients during neurosurgery of the posterior fossa. Each set of measurements of PCWP and RAP included measurements during induction of anesthesia in the supine position and the seated position prior to surgery. The PCWP and RAP were recorded during PEEP = 0 cm H2O, PEEP = 10 cm H2O, or with PASG inflation to pressures ranging from 40 to 80 mm Hg. The RAP increased from 8 +/- 6 to 20 +/- 7 mm Hg (PASG) and to 11 +/- 5 mm Hg (PEEP) in the seated position without a significant (p >0.05) change in the PCWP-RAP difference under any of the above conditions. We conclude that PASGs are a safer and more effective means of raising the RAP than PEEP ventilation during seated neurosurgical procedures without the danger of paradoxical air embolism.

Journal Article↗

PubMed2005

Short-term recurrent abdominal pain related to Helicobacter pylori infection in children.

BACKGROUND AND AIM: The causal relationship between Helicobacter pylori infection and recurrent abdominal pain in children is still under debate. This study assessed the relationship between H. pylori infection and recurrent abdominal pain (RAP) in preschool and school children. METHODS: A total of 1271 preschool and school children completed a questionnaire to define the RAP or short-term RAP (SRAP) with pain duration from 2 weeks to 3 months. The serum samples of 118 children with RAP, 60 with SRAP and 212 control children without abdominal pain were all tested for anti-H. pylori IgG. Children with abdominal pain and anti-H. pylori seropositivity were followed for 1 year to assess the relationship of H. pylori infection and recurrent abdominal pain. RESULTS: The prevalence rates of RAP and SRAP in children were 9.8% (124/1271) and 5.5% (70/1271), respectively. Children with SRAP had a higher anti-H. pylori seropositive rate than those with RAP (25%vs 5%, P < 0.001) and control (25%vs 9%, P = 0.001). Among children with SRAP, the epigastric pain was related to H. pylori infection (P = 0.002). One year later, 71% (15/21) of the follow-up children (15 with SRAP, six with RAP) became symptom free regardless of the persistence of H. pylori. CONCLUSION: H. pylori infection is more commonly found in children with short-term RAP, and presentation of epigastric pain in these cases can be considered as a warning alarm to screen for H. pylori infection.

Abdominal Pain↗

PubMed2004

Parasympathetic blockade promotes recovery from atrial electrical remodeling induced by short-term rapid atrial pacing.

The purpose of the present study was to assess the influence of autonomic blockade on shortening of effective refractory period (ERP) induced by short-term rapid atrial pacing (RAP) and its recovery process. Fifteen patients (8 men, 7 women, age 52 +/- 16 years) without structural heart disease and without a history of atrial fibrillation were included in this study. All patients underwent RAP at a cycle length of 300 ms for 5 minutes, after which the ERP was measured in all patients at 1, 3, 5, 7.5, and 10 minutes following cessation of RAP. In ten patients, these RAP and measurements of ERPs were repeated after administration of propranolol (P) and subsequent administration of atropine (P + A), respectively. In the remaining five patients atropine (A) was given first and then the administration of propranolol followed (P + A). Relative to the baseline value, the ERP immediately after RAP did not differ significantly from the Control(C), P, A, or P + A (C, 79%+/- 8%; P, 82%+/- 9%; A, 80%+/- 6%; P + A, 82%+/- 13%). However, the ERP 3 minutes after cessation of RAP was significantly (P < 0.05) longer in A (93%+/- 4%) and P + A (97%+/- 5%) than that in C (86%+/- 5%) and P (86%+/- 5%). The recovery time for ERP to return to pre-RAP value was significantly shorter during A and P + A than during either C or P (C, 536 +/- 161 s; P, 503 +/- 172 s; A, 282 +/- 111 s; P + A, 291 +/- 147 s; P < 0.05). Parasympathetic blockade may promote recovery from ERP shortening induced by short-term RAP.

Atropine↗

PubMed1988

Haemodynamic regulation of renal prostaglandin and renin release.

To examine the relationship between renal release of the prostaglandins E2 (PGE2) and I2 (PGI2) and renin during autoregulatory vasodilation, experiments were performed in anaesthetized dogs with denervated kidneys. Autoregulatory vasodilation was induced by reducing renal arterial pressure (RAP) or by raising ureteral pressure in steps. During progressive renal arterial constriction, PGE2 and PGI2 release reached maximal values (10.6 +/- 1.7 for PGE2 and 6.6 +/- 1.1 pmol min-1 for PGI2 release) at RAP of 70-80 mmHg, associated with almost no increase in renin release. By further reduction of RAP, prostaglandin release was not significantly altered, whereas renin release reached maximal values (18.7 +/- 2.4 micrograms AI min-1) when autoregulatory vasodilation was complete at RAP below 55-60 mmHg. During progressive elevation of ureteral pressure, the release of PGE2, PGI2 and renin increased in concert in a curvilinear fashion, reaching maximal values at a ureteral pressure of 85 mmHg. There was no further increase during ureteral occlusion and the plateau values averaged 23.6 +/- 3.7 pmol min-1 for PGE2, 8.0 +/- 1.6 pmol min-1 for PGI2 and 16.6 +/- 3.4 micrograms AI min-1 for renin. We conclude that vascular dilation enhances both prostaglandin and renin release. During reduction of RAP, preglomerular arteries are dilated at higher RAP than are afferent arterioles. Release of prostaglandins synthetized in arteries consequently occurs at higher RAP than release of renin, which is not enhanced until afferent arterioles ultimately dilate at RAP approaching 60 mmHg. In contrast, elevation of ureteral pressure provides nearly uniform enhancement of prostaglandin and renin release, indicating a more uniform dilation of the whole preglomerular vascular tree.

Animals↗

PubMed1993

Immunogenic B-cell epitopes of Babesia bovis rhoptry-associated protein 1 are distinct from sequences conserved between species.

Babesia bovis merozoite apical membrane polypeptide Bv60 was found to be rhoptry associated by immuno-electron microscopy and was redesignated rhoptry-associated protein 1 (RAP-1). The N-terminal 300 amino acids of RAP-1 have a high level of sequence similarity to the same N-terminal region of p58, its homolog from Babesia bigemina. However, the interspecies conserved sequences did not include RAP-1 surface-exposed B-cell epitopes as defined by monoclonal antibodies. Furthermore, neither heterologous B. bigemina immune nor monospecific anti-p58 bovine serum binds to whole RAP-1, indicating that the major B-cell epitopes recognized by these sera are also not encoded by the conserved sequences. Truncated RAP-1, expressed by a subclone encoding the N-terminal 235 amino acids, is weakly bound by antibodies in heterologous sera. A peptide representing the longest conserved amino acid sequence (amino acids 121 to 134) in this region is also weakly bound by antibodies in immune bovine sera, and rabbit antibodies induced by and strongly reactive with the peptide alone fail to bind native or denatured RAP-1. Thus, although the conserved region may contain one or more poorly immunogenic B-cell epitopes, these epitopes are inaccessible to antibody in whole RAP-1. The results indicate that the major immunogenic B-cell epitopes of RAP-1, including surface-accessible epitopes bound by monoclonal antibodies, are distinct from the conserved sequences representing putative functional domains.

Amino Acid Sequence↗

PubMed2001

Rhoptry-associated protein 1-binding monoclonal antibody raised against a heterologous peptide sequence inhibits Plasmodium falciparum growth in vitro.

Monoclonal antibodies (MAbs) specific for Plasmodium falciparum rhoptry-associated protein 1 (RAP-1) were generated and tested for inhibition of parasite growth in vitro. The majority of indirect immunofluorescence assay (IFA)-positive MAbs raised against recombinant RAP-1 positions 23 to 711 (rRAP-1(23-711)) recognized epitopes located in the immunodominant N-terminal third of RAP-1. MAbs specific for the building block 35.1 of the synthetic peptide malaria vaccine SPf66 also yielded an IFA staining pattern characteristic for rhoptry-associated proteins and reacted specifically with rRAP-1 and parasite-derived RAP-1 molecules p67 and p82. Cross-reactivity with RAP-1 was blocked by the 35.1 peptide. Epitope mapping with truncated rRAP-1 molecules and overlapping peptides identified the linear RAP-1 sequence Y218KYSL222 as a target of the anti-35.1 MAbs. This sequence lacks primary sequence similarity with the 35.1 peptide (YGGPANKKNAG). Cross-reactivity of the anti-35.1 MAbs thus appears to be associated with conformational rather than sequence homology. While the anti-35.1 MAb SP8.18 exhibited parasite growth-inhibitory activity, none of the tested anti-rRAP-1(23-711) MAbs inhibited parasite growth, independently of their fine specificity for the RAP-1 sequences at positions 33 to 42, 213 to 222, 243 to 247, 280 to 287, or 405 to 446. The growth-inhibitory activity of MAb SP8.18 was, however, accelerated by noninhibitory anti-RAP-1 MAbs. Results demonstrate that in addition to fine specificity, other binding parameters are also crucial for the inhibitory potential of an antibody.

Amino Acid Sequence↗

PubMed2002

Autoregulation of renal medullary blood flow in rabbits.

We examined the extent of renal medullary blood flow (MBF) autoregulation in pentobarbital-anesthetized rabbits. Two methods for altering renal arterial pressure (RAP) were compared: the conventional method of graded suprarenal aortic occlusion and an extracorporeal circuit that allows RAP to be increased above systemic arterial pressure. Changes in MBF were estimated by laser-Doppler flowmetry, which appears to predominantly reflect erythrocyte velocity, rather than flow, in the kidney. We compared responses using a dual-fiber needle probe held in place by a micromanipulator, with responses from a single-fiber probe anchored to the renal capsule, to test whether RAP-induced changes in kidney volume confound medullary laser-Doppler flux (MLDF) measurements. MLDF responses were similar for both probe types and both methods for altering RAP. MLDF changed little as RAP was altered from 50 to >or=170 mmHg (24 +/- 22% change). Within the same RAP range, RBF increased by 296 +/- 48%. Urine flow and sodium excretion also increased with increasing RAP. Thus pressure diuresis/natriuresis proceeds in the absence of measurable increases in medullary erythrocyte velocity estimated by laser-Doppler flowmetry. These data do not, however, exclude the possibility that MBF is increased with increasing RAP in this model, because vasa recta recruitment may occur.

Anesthesia↗

PubMed2003

Dynamics and contribution of mechanisms mediating renal blood flow autoregulation.

We investigated dynamic characteristics of renal blood flow (RBF) autoregulation and relative contribution of underlying mechanisms within the autoregulatory pressure range in rats. Renal arterial pressure (RAP) was reduced by suprarenal aortic constriction for 60 s and then rapidly released. Changes in renal vascular resistance (RVR) were assessed following rapid step reduction and RAP rise. In response to rise, RVR initially fell 5-10% and subsequently increased approximately 20%, reflecting 93% autoregulatory efficiency (AE). Within the initial 7-9 s, RVR rose to 55% of total response providing 37% AE, reaching maximum speed at 2.2 s. A secondary RVR increase began at 7-9 s and reached maximum speed at 10-15 s. Response times suggest that the initial RVR reflects the myogenic response and the secondary tubuloglomerular feedback (TGF). During TGF inhibition by furosemide, AE was 64%. The initial RVR rise was accelerated and enhanced, providing 49% AE, but it represented only 88% of total. The remaining 12% indicates a third regulatory component. The latter contributed up to 50% when the RAP increase began below the autoregulatory range. TGF augmentation by acetazolamide affected neither AE nor relative myogenic contribution. Diltiazem infusion markedly inhibited AE and the primary and secondary RVR increases but left a slow component. In response to RAP reduction, initial vasodilation constituted 73% of total response but was not affected by furosemide. The third component's contribution was 9%. Therefore, RBF autoregulation is primarily due to myogenic response and TGF, contributing 55% and 33-45% in response to RAP rise and 73% and 18-27% to RAP reduction. The data imply interaction between TGF and myogenic response affecting strength and speed of myogenic response during RAP rises. The data suggest a third regulatory system contributing <12% normally but up to 50% at low RAP; its nature awaits further investigation.

Acetazolamide↗

PubMed1991

Role of angiotensin in ameliorating the renal actions of norepinephrine.

To determine the importance of the arterial pressure effects of angiotensin II (ANG II) on renal function during acute renal adrenergic stimulation, we examined the effects of a 2-h intrarenal arterial infusion of norepinephrine (NE) at 0.1 and 0.25 micrograms.kg-1.min-1 on renal function in five conscious dogs during 1) control conditions, 2) servo-control of renal arterial pressure (RAP) at control levels, and 3) chronic captopril administration. The low rate of NE infusion produced an approximately 20% decrease in glomerular filtration rate (GFR) and renal plasma flow (RPF) and an approximately 8-mmHg increase in RAP in association with an approximately 2.5-fold rise in plasma renin activity (PRA). The high rate of NE infusion produced greater increments in both PRA and RAP and an approximately 50% reduction in GFR and RPF. Neither servo-control of RAP nor captopril administration significantly affected the above renal responses to the low rate of NE infusion. In marked contrast, when increases in RAP (approximately 20 mmHg) were prevented at the high rate of NE infusion by servo-control of RAP, both the PRA and renal responses were enhanced. Furthermore, when RAP was reduced (approximately 25 mmHg) as a result of chronically blocking the renin-angiotensin system with captopril, the renal responses to the high rate of NE infusion were exaggerated even further; in four of five dogs, total renal ischemia occurred in response to NE. These results indicate that ANG II indirectly ameliorates the renal actions of renal adrenergic stimulation by increasing RAP.

Angiotensin II↗

PubMed1983

Alteration of renal baroreceptor by salt intake in control of plasma renin activity in conscious dogs.

We investigated the relationship between renal arterial pressure (RAP) and systemic plasma renin activity (PRA) in five uninephrectomized conscious dogs on normal salt (80 meq Na+/day) and low salt (10 meq Na+/day) diets. The RAP was controlled by an inflatable cuff placed around the origin of the renal artery. In both salt states the PRA was an exponential function of the RAP: log (PRA) = (-0.026 X RAP) + 2 on the normal salt diet (r = 0.96) and log (PRA) = (-0.026 X RAP) + 2.5 on the low salt diet (r = 0.99). At any RAP, the value of the low salt PRA was 3 times that of the normal salt PRA. Accordingly, a reduction in salt intake increases the sensitivity of the renal baroreceptor so that the absolute value of PRA increases at any RAP, but the percentage change in PRA caused by any change in RAP is the same in both normal and low salt states.

Animals↗

PubMed1987

Atrial pacing during percutaneous transluminal coronary angioplasty: results and comparison with exercise treadmill testing.

Right atrial pacing (RAP) was used to immediately assess improvement in threshold for myocardial ischemia in 23 patients undergoing angiographically successful percutaneous transluminal coronary angioplasty (PTCA). Multiple coronary lesions were present in 19 patients, and 15 had incomplete revascularization. All patients had RAP done immediately before and after completion of all dilatations, and in 13 patients pre- and post-PTCA exercise treadmill tests (ETT) were also performed. Angina occurred in 16 (70%) patients during pre-PTCA RAP, but in only 4 (17%) after PTCA (p less than .05). The electrocardiogram was positive for ischemia (horizontal or downsloping ST depression greater than or equal to 1 mm) in 18 patients (78%) during pre-PTCA RAP. However, 13 patients (57%) continued to have an ischemic response during post-PTCA RAP (not significant-NS). In 4 patients with multiple coronary lesions who had sequential pacing studies after PTCA of each lesion, the maximum degree of ST depression decreased by 1 mm or more after each dilatation in 3 patients but remained greater than or equal to 1 mm in all. In the 13 patients undergoing both RAP and ETT, angina developed in 7 during pre-PTCA RAP and in 2 after PTCA (p less than .05), compared with 8 and 3 (p less than .05) during pre- and post-PTCA ETT, respectively. Ischemic ST depression occurred in 9 patients during pre-PTCA RAP and in 6 after PTCA (NS), and in 8 and 6 (NS) during pre- and post-PTCA ETT, respectively. Concordance between the two tests was good.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2004

Recurrent abdominal pain, anxiety, and depression in primary care.

OBJECTIVE: The prevalence of psychiatric disorder in children and adolescents with functional recurrent abdominal pain (RAP) is unknown. Our aim was to determine whether RAP is associated with psychiatric symptoms and disorders, anxious temperament, and functional impairment in pediatric primary care. METHODS: Children and adolescents who were 8 to 15 years of age, inclusive, and presented with RAP (N = 42) or for routine care in the absence of recurrent pain (N = 38) were identified by a screening procedure in pediatric primary care office waiting rooms and recruited to participate in a case-control study. Outcome measures were psychiatric diagnoses generated by standardized psychiatric interview administered blind to subject status and self, parent, and clinician ratings of child psychiatric symptoms, temperamental traits, and functional status. RESULTS: RAP patients were significantly more likely to receive a diagnosis of a psychiatric disorder, with a categorical anxiety disorder in 33 (79%) and a depressive disorder in 18 patients (43%), and higher levels of anxiety and depressive symptoms, temperamental harm avoidance, and functional impairment than control subjects. Anxiety disorders (mean age of onset: 6.25 [standard deviation: 2.17] years) were significantly more likely to precede RAP (mean age of onset: 9.17 [standard deviation: 2.75] years) in patients with associated anxiety. CONCLUSIONS: Youths who present with RAP in primary care deserve careful assessment for anxiety and depressive disorders. Future studies should examine treatments that are proved to be efficacious for pediatric anxiety and/or depressive disorders as potential interventions for RAP. Longitudinal, family, and psychobiological studies are needed to illuminate the nature of observed associations among RAP, anxiety, and depression.

Abdominal Pain↗

PubMed2003

Percentage of peak-to-peak pulsatility of portal blood flow can predict right-sided congestive heart failure.

AIM: To study the change of portal blood flow for the prediction of the status of right-sided heart failure by using non-invasive way. METHODS: We studied 20 patients with rheumatic and atherosclerotic heart diseases. All the patients had constant systemic blood pressure and body weight 1 week prior to the study. Cardiac index (CI), left ventricular end-diastolic pressure (LVEDP), mean aortic pressure (AOP), pulmonary wedge pressure (PWP), mean pulmonary arterial pressure (PAP), mean right atrial pressure (RAP), right ventricular end-diastolic pressure (RVEDP) were recorded during cardiac catheterization. Ten patients with RAP >10 mmHg were classified as Group 1. The remaining 10 patients with RAP >=10 mmHg were classified as Group 2. Portal blood velocity profiles were studied using an ultrasonic Doppler within 12 h after cardiac catheterization. RESULTS: CI, AOP, and LVEDP had no difference between two groups. Patients in Group 1 had normal PWP (14.6+/-7.3 mmHg), PAP (25.0+/-8.2 mmHg), RAP (4.7+/-2.4 mmHg), and RVEDP (6.4+/-2.7 mmHg). Patients in Group 2 had increased PWP (29.9+/-9.3 mmHg), PAP (46.3+/-13.2 mmHg), RAP (17.5+/-5.7 mmHg), and RVEDP (18.3+/-5.6 mmHg) (P<0.001). Mean values of maximum portal blood velocity (Vmax), mean portal blood velocity (Vmean), cross-sectional area (Area) and portal blood flow volume (PBF) had no difference between 2 groups. All the patients in Group 1 had a continuous antegrade portal flow with a mean percentage of peak-to-peak pulsatility (PP) 27.0+/-8.9 % (range: 17-40 %). All the patients in Group 2 had pulsatile portal flow with a mean PP 86.6+/-45.6 (range: 43-194 %). One patient had a transient stagnant and three patients had a transient hepatofugal portal flow, which occurred mainly during the ventricular systole. Vmax, Vmean and PBF had a positive correlation with CO (P<0.001) but not with AOP, LVEDP, PWP, PAP, RAP, and RVEDP. PP showed a good correlation (P<0.001) with PWP, PAP, RAP, and RVEDP but not with CI, AOP, and LVEDP. All the patients with PP >40 % had a right-sided heart failure with a RAP=10 mmHg. CONCLUSION: The measurement of PP change is a simple and non-invasive way to identify patients with right heart failure.

Adult↗

PubMed2002

Echocardiographic [correction of Ehocardiographic] evaluation of regional left atrial function after rapid atrial pacing.

Rapid regular atrial pacing (RAP) produces changes in atrial function similar to those caused by atrial fibrillation in animal models. Left atrial appendage (LAA) function represents regional atrial function. The aim of our study was to investigate the influence of RAP on left atrial regional function and to evaluate the reversibility of changes after termination of pacing in a canine model. Eight dogs were subjected to RAP (400 bpm) for 16 days. Transesophageal echocardiography was performed at baseline, immediately after RAP and 4 weeks after the termination of RAP. The LAA peak late emptying velocity (LAA-E) and filling wave (LAA-f) were measured. LAA-E velocities were significantly reduced and filling wave velocities (LAA-f) were significantly less negative after RAP compared with the baseline values. Four weeks after termination of pacing, the LAA-E and LAA-f velocities were normal. RAP results in impaired regional atrial systolic and diastolic function. The changes were completely reversible 4 weeks after termination of pacing. These results suggest that the LAA is mechanically stunned after RAP.

Animals↗

PubMed2005

[The influence of persistent rapid atrial pacing on the levels of connexin 43 and type III collagen in pulmonary vein and atrium in a canine model].

OBJECTIVE: To investigate the influence of persistent rapid atrial pacing on the levels of connexin 43 (Cx43) and type III collagen in pulmonary vein and atrium in a canine model. METHODS: Sixteen mongrel dogs were divided into rapid atrial pacing (RAP) group (n = 8) and normal control group (n = 8) randomly. In the RAP group, atrial pacing was performed with a rate of 400 bpm for 10 weeks to establish atrial fibrillation model. The tissues of left superior pulmonary vein (LSPV), left atrial free wall (LAFW) and right atrial appendage (RAA) were collected from each dogs. The levels of Cx43 and type III collagen were measured in each tissue. RESULTS: Ten weeks later, persistent atrial fibrillation was induced in all dogs in RAP group. The level of Cx43 in RAP group was higher than that in normal control group (LSPV: 3370.91 +/- 275.11 vs 1405.82 +/- 90.38, P < 0.05; LAFW: 2448.68 +/- 272.10 vs 1467.12 +/- 147.93, P < 0.05, RAA: 2331.96 +/- 199.61 vs 1288.27 +/- 216.22, P < 0.05). The level of Cx43 in LSPV was higher than that in LAFW and RAA in RAP group, whereas the difference between LAFW and RAA was not significant in RAP group. The quantities of type III collagen in RAP group were higher than those in normal control group (LSPV: 3301.97 +/- 309.70 vs 1404.56 +/- 178.02, P < 0.05; LAFW: 2477.86 +/- 190.43 vs 1479.20 +/- 187.17, P < 0.05; RAA: 2045.92 +/- 139.43 vs 1417.07 +/- 139.43, P < 0.05). The quantities of type III collagen in LSPV was higher than those in LAFW and RAA in RAP group. CONCLUSIONS: Persistent rapid atrial pacing could increase the levels of Cx43 and type III collagen in pulmonary vein and atrium in a canine model of atrial fibrillation. The levels of Cx43 and type III collagen in pulmonary vein were higher than those in atrium. This findings indicated that pulmonary vein may be a crucial regions in maintaining atrial fibrillation.

Animals↗

PubMed1988

Factors involved in specific transcription by mammalian RNA polymerase II. RNA polymerase II-associating protein 30 is an essential component of transcription factor IIF.

Transcription from class II promoters requires five general factors, IIA, IIB, IID, IIE, and IIF, in addition to RNA polymerase II for basal levels of transcription (Reinberg, D., Flores, O., and Buckbinder, L. (1987) in Molecular Biology of RNA: New Perspectives (Inouye, M., and Dudock, B., eds) pp. 423-439, Academic Press, Orlando, FL). A protein fraction containing transcription factors (TF) IIE and IIF was able to reconstitute transcription from the adenovirus major late promoter when added to extracts depleted of the RNA polymerase II-associating proteins RAP 30 and RAP 74 (Sopta, M., Carthew, R.W., and Greenblatt, J. (1985) J. Biol. Chem. 260, 10353-10360). Studies with monoaffinity-purified antibodies directed against RAP 30 demonstrated, by Western blot analysis, that RAP 30 copurifies on five columns with transcription factor IIF. That RAP 30 is a functional component of TFIIF was also demonstrated; preincubation of anti-RAP 30 antibodies with purified TFIIF inhibited transcription. Inhibition of transcription was overcome by the addition of purified TFIIF. RAP 30 is an integral part of a preinitiation complex; the incubation of all the general transcription factors with a promoter-containing DNA, prior to the addition of the anti-RAP 30 antibodies, resulted in the formation of a DNA-protein complex that was not inhibited by the antibodies. Incubation of the transcription factors in the absence of a promoter-containing DNA resulted in a complex that was partially resistant to the antibodies.

Adenoviruses, Human↗

PubMed1993

Immunocytochemical and biochemical characterization of the Heymann nephritis antigenic complex in rat L2 yolk sac cells.

Heymann nephritis in the rat is the most widely used model of human membranous glomerulonephritis. Glycoprotein (gp)330, a large (M(r) > 550,000) membrane-associated glycoprotein, has been identified as the main antigen in this autoimmune disease. Studies of gp330 and receptor-associated protein (RAP), its 44-kd subunit, have been restricted largely to rat kidney, as no stable cultured cell line has been available that expresses gp330. We have recently identified a rat yolk sac carcinoma cell line (L2) that expresses both gp330 and RAP. In this report, we have carried out detailed morphological, immunocytochemical, and biochemical studies characterizing the biosynthesis and localization of gp330 and RAP in the L2 rat yolk sac cell line. At the electron microscope level, the L2 cells are seen to be attached by cell junctions, and their predominant morphological features include extensive networks of rough endoplasmic reticulum (ER) and numerous clathrin-coated pits found on the cell membrane. By immunocytochemistry, gp330 was localized primarily to clathrin-coated pits at the cell surface, whereas RAP was localized predominantly to the lumen of the rough ER. Pulse-chase experiments indicated that gp330 spends a prolonged time maturing in the ER of L2 cells, as transport of gp330 to the Golgi complex (based on acquisition of endoglycosidase H resistance) is slow (t1/2 = 90 to 120 minutes). Gp330 reached the L2 cell surface beginning at 2 hours after synthesis, where it could be detected by cell surface immunoprecipitation. RAP was found to be an N-linked glycoprotein, and it remained endoglycosidase H-sensitive up to 4 hours after synthesis. Co-precipitation and co-sedimentation experiments demonstrated that gp330 and RAP form a large heterodimer (M(r) approximately 669,000) immediately after biosynthesis and are further assembled into a large hetero-oligomer in the ER. These findings demonstrate that the localization and the kinetics of assembly of gp330 and RAP into the Heymann nephritis antigenic complex are similar in both L2 cells and rat kidney. They also provide new information on the intracellular processing of these two molecules and their delivery to the cell surface. Thus, the L2 cell system should facilitate further characterization of the functions and interactions of gp330 and RAP, which may shed light on the cellular and molecular mechanisms of Heymann nephritis.

Animals↗