Biomedical subjects

J Ménard

Publications and source records attributed to J Ménard.

At least 163 records · Page 9Linked to original sources

PubMed1987

[The decision to treat moderate hypertension: repetition of office visits or ambulatory monitoring of arterial pressure?].

World Health Organization (WHO) recommends antihypertensive therapy for mild to moderate hypertensive patients after 3 or more visits. We tested the hypothesis that an ambulatory blood pressure recording could also help to decide which patient need therapy. Blood pressure was measured in 89 essential, uncomplicated, hypertensive patients (diastolic (DBP): 90-110 mmHg, mean age: 41 +/- 13 years), with a mercury sphygmomanometer at 3 visits and with an ambulatory blood pressure recorder (Spacelabs) during 12 hours. According to WHO recommendations, patients were classified "WHO+" if they need a treatment (n = 44) and "WHO-" if they did not. The mean ambulatory DBP of each subject was compared to the arbitrary limit defined as the mean +2 standard deviations of the ambulatory DBP of a population of normotensive subjects in the same decade and same sex: patients with ambulatory DBP above this limit were defined "AMB+" (n = 27), the others were "AMB-". Ten patients were "WHO- AMB+" and 24 were "WHO+ AMB-". These discordances were independent of age, body weight, duration of hypertension, variability of ambulatory systolic and diastolic blood pressure defined by the standard deviation. By contrast, the difference between the measurements of the simultaneous blood pressure measurements performed with the two methods (mercury sphyngmomanometer and Spacelabs) 2 times by each patient could explain in part these discrepancies. The Spacelabs underestimates DBP measured with the mercury sphyngmomanometer in patients "AMB-" but not in patient "AMB+".(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure Determination↗

PubMed1987

[Predictive factors of resistance to antihypertensive treatment].

Results of antihypertensive treatment were analyzed in a group of 5,209 hypertensive patients referred in two hypertension Clinics in Paris from 1976 to 1985. Patients were included in the study if they fulfilled the following criteria: 1) at least four visits in the clinic, 2) follow-up period greater than 6 months, 3) initial diastolic blood pressure greater than or equal to 90 mmHg and/or presence of an antihypertensive treatment. After a mean follow-up period of 43 months, blood pressure was reduced from 177/105 mmHg to 148/89 mmHg. However, in spite of at least two antihypertensive drugs, 16.7 p. 100 of these patients had a diastolic blood pressure above 95 mmHg at the end of the follow-up period and were defined as uncontrolled hypertensives (UH). By comparison with controlled hypertensives (CH), UH patients were more frequently males (67.9 vs 56.6 p. 100, p less than 0.001), had a greater known duration of hypertension (11.6 vs 8.7 years, p less than 0.001), and presented at the first visit with higher blood pressures (188/113 vs 174/103 mmHg, p less than 0.001/p less than 0.001), despite a higher rate of antihypertensive treatment (66.6 vs 53.8 p. cent, p less than 0.001), a higher ponderal index (26.3 vs 25.3/kg/m2, p less than 0.01) and a higher prevalence of end-organ damage (23.2 vs 16.3 p. 100, p less than 0.001). Sokolov index, serum creatinine and uric acid levels were higher among UH than among CH patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗

PubMed1987

[Measurement of platelet catecholamine content for the diagnosis of pheochromocytoma with intermittent hypertension].

We have compared platelet and plasma catecholamines (radioenzymatic assay with catechol-O-methyl transferase) and urinary metanephrines (high performance liquid chromatography) in 16 patients with phaeochromocytoma, 12 essential hypertensives, and 15 normotensive volunteers. Hypertensive patients with or without phaeochromocytoma had labile or paroxysmal hypertension with normal or borderline blood pressures between paroxysms. Catecholamine concentrations in platelets and plasma did not differ in essential hypertensives and controls, but were higher in patients with phaeochromocytoma than in subjects without tumour, with values overlapping between groups. Metanephrine excretion was markedly higher in phaeochromocytoma than in essential hypertension, with no intergroup overlap. Platelet adrenaline plus noradrenaline content was highly correlated to urinary metanephrines (r' = 0.830, n = 28 p less than 0.01). Using as a cut-off point the highest values measured in essential hypertensives, the sensitivity of each measurement was 1.00 for metanephrines, 0.87 for platelet catecholamines and 0.50 or less for plasma catecholamines. Measurement of platelet catecholamine content is a sensitive test and an appropriate alternative to metanephrine measurement in the difficult cases of suspected phaeochromocytoma with intermittent hypertension.

Adrenal Gland Neoplasms↗

PubMed1987

[Double-blind evaluation of slow-release nicardipine using different methods of blood pressure measurement. Predictive value of the acute response to intravenous nicardipine].

Forty hypertensive patients (diastolic greater than 95 mmHg) were included after 15 days of a single blind placebo period in a randomized placebo controlled double-blind study to assess the antihypertensive effect of a new galenic form of nicardipine (N) administered 50 mg b.i.d. for 3 weeks. They comprised 27 men and 13 women aged from 27 to 72 years (mean: 53 +/- 10). Blood pressure (BP) was measured in hospital before morning drug intake by an automatic recorder (Sentron) in supine position for 30 minutes (min) and by a mercury sphygmomanometer. Ambulatory BP was assessed by a portable patient activated recorder (Remler 2000). Mercury sphygmomanometer supine BP under N fell from 160 +/- 21/104 +/- 6 mmHg to 151 +/- 14/98 +/- 8 mmHg (n = 20; p less than 0.01/p less than 0.01) whereas BP under placebo (P) was respectively 158 +/- 14/103 +/- 6 mmHg and 156 +/- 20/102 +/- 9 mmHg (NS). Sentron BP under N fell from 158 +/- 17/96 +/- 8 mmHg to 148 +/- 13/90 +/- 7 mmHg (p less than 0.001/p less than 0.01) with no BP change under P (152 +/- 12/93 +/- 7 mmHg to 151 +/- 14/93 +/- 8 mmHg NS). BP recorder every 30 min for 12 hours revealed a decrease under N (160 +/- 18/105 +/- 10 mmHg to 142 +/- 16/94 +/- 10 mmHg; p less than 0.001/p less than 0.001) with a placebo effect in the control group on the diastolic BP (160 +/- 15/103 +/- 7 mmHg to 156 +/- 16/100 +/- 8 mmHg/NS/p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1987

[Decentralization of the ARTEMIS system in a nephrology service in a general hospital].

"ARTEMIS" is a standardized and computerized medical file which is intended for improving the follow-up of hypertensive patients, the efficacy of treatment and for realising national-wide surveys. The software "LIED" of data base for "ARTEMIS" is nowadays transposable on mini-computer. In Nephrology Unit of General Hospital from Colmar, the system has been working since September 1985 with MICRO-MEGA E 32 (Thomson). The administrative and medical data are directly acquired by the doctors and secretaries of the Unit on a conversational mode from six terminals. There is no writing collecting of data. An evaluation of the system was realized with the 113 first hypertensive patients. The results were compared to those obtained from patients of Paris area.

Follow-Up Studies↗

PubMed1987

[Results of the surgical treatment of Conn's adenomas].

During the last 10 years we operated on 69 Conn's adenomas of which 59 were followed up for a mean period of 16 months (range: 3-96 months). Surgery cured the hypertension (blood pressure less than 140/90) in 47 p. 100 of the patients. Improved blood pressure (systolic: mean = 46 mmHg; range 0-135 mmHg and diastolic: mean = 25 mmHg; range 0-66 mmHg) was noted in another 47 p. 100 of patients whereas no blood pressure change was noted in 3 patients. Biological primary aldosteronism was found post-operatively in 2 of these 3 patients and also in one whose hypertension was improved. In this last patient plus the three unimproved by surgery, small tumours (less than 10 mm) were found and co-existnt multifocal hyperplasia was found in the 2 patients who had had an adrenalectomy. Fifty-one patients were treated pre-operatively by spironolactone (SP) alone (3.2 +/- 1.3 mg/kg) for a mean period of 6.8 weeks (range: 3 to 20 weeks). Only 2 of the 24 patients controlled by SP were not cured by surgery and one of them had persistnt primary aldosteronism. Conversely, 3 of the 27 uncontrolled by SP were cured post-operatively, and these exceptions could be due to the weak dose of SP (n = 2) and an observance problem (n = 1). Patients cured by surgery had shorter duration of hypertension (4.3 +/- 3.0 years vs 10.1 +/- 8.1; p less than 0.01) and lower diastolic pressure (111 +/- 14 mmHg vs 121 +/- 12; p less than 0.01) than uncured patients. No significant difference between these two groups was observed with respect to systolic pressure, age, sex, plasma potassium, plasma renin activity and plasma aldosterone levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗

PubMed1987

Integrating management and expertise in a computerised system for hypertensive patients.

An expert system has been integrated to the data management system of the ARTEMIS programme for hypertensive patients. The patient database, which has been used since 1975, contains the medical records of about 20,000 patients. Information is interactively entered by physicians, nurses and secretaries on video display units. The computerised medical record has replaced the traditional handwritten medical record. The database management system is used to produce different summary reports (inpatient and outpatient care) and personalized recall letters which are mailed to the patients before their appointments. Suggestions provided by the expert system include additional information to be obtained (complementary patient interrogation, biological or radiological investigations, etc.), possible causes of hypertension, and medical prescriptions. The information base allows the description of both static knowledge (in the form of a semantic network) and dynamic knowledge (in the form of production rules). The inference system sequentially uses a combination of forward and backward chaining and performs both exact and approximate reasoning. The diagnostic performance of the expert system was evaluated in 100 cases of hypertension (50 of essential hypertension and 50 of secondary hypertension. Concordance between the diagnosis proposed by the expert system and the one proposed by the specialist was achieved in 92% of secondary hypertension cases and 88% of essential hypertension cases. It is suggested that the integration of data and knowledge management might enhance the overall acceptance by medical staff of a computerised system, and facilitate the validation of a knowledge base.

Database Management Systems↗

PubMed1987

Direct radioimmunoassay for rat high molecular weight kininogen. Measurement of immunoreactive high molecular weight kininogen in normal and kininogen deficient plasma.

A direct radioimmunoassay (RIA) for rat high molecular weight kininogen (HMW Kg) was developed that enabled us to detect 71 fmol/ml of HMW Kg. The antibodies did not crossreact in the RIA with up to 5 nmol of purified rat alpha 1 cysteine proteinase inhibitor (T-kininogen). When various quantities of pure HMW Kg were either quantified by the RIA or by the measurement of kinin contents determined after trypsin hydrolysis, identical values were obtained by both methods. This RIA allowed the measurement of HMW Kg in 0.015 to 1 microliter of rat plasma. HMW Kg levels in plasma of Wistar rats and in Brown Norway rats of the Orlean Strain (BN/Orl) were 1.52 +/- 0.05 (n = 6) and 2.050 +/- 0.015 (n = 8) nmol/ml respectively. In the Brown Norway rats of the Katholiek strain (BN/Kat) that are considered to be deficient in HMW Kg, immunoreactive HMW Kg levels were less than 2% of those of the BN/Orl rats. These results confirm that the BN/Kat animals have a molecular defect in HMW Kg.

Animals↗

PubMed1986

Influence of converting enzyme inhibition on the hormonal and renal adaptation to hyper- and hyponatraemic dehydration.

The present study was designed to investigate in rats the influence of converting enzyme inhibition with captopril on blood pressure, plasma urea, plasma renin concentration (PRC), plasma aldosterone and plasma vasopressin, and to define the interrelationships between PRC and these variables during equal degrees of either hyponatraemic (furosemide, 40 mg/kg for 2 days) or hypernatraemic (48-h water deprivation) dehydration. Chronic treatment with captopril (40 mg/kg daily) decreased blood pressure by 19% in normally hydrated treated rats, by 27% in water-deprived treated rats and by 40% in furosemide-treated rats. Plasma renin concentration, plasma aldosterone and plasma vasopressin were increased during both hypo- and hypernatraemic dehydration. Captopril decreased plasma aldosterone in water-deprived and furosemide-treated rats, whereas plasma vasopressin was unchanged. The significant correlation observed between plasma aldosterone and PRC in non-treated rats persisted in treated rats, the same level of plasma aldosterone being observed at values of PRC 10 times higher. On the other hand, the correlation between plasma vasopressin and PRC did not persist in captopril-treated rats. An increase in plasma urea was observed in both water-deprived treated rats and furosemide-treated rats. These data indicate that during hypo- and hypernatraemic dehydration, the renin-angiotensin system plays a role in regulating blood pressure, urea elimination and plasma aldosterone, but vasopressin regulation is not modified by its inhibition.

Aldosterone↗

PubMed1986

Study of the antigenic determinants of human renin.

The primary structure of human renin, recently established from the complementary DNA sequence of its messenger RNA, shows a strong homology to other aspartyl proteases. This homology has permitted the construction of a model of the three-dimensional structure of renin based on the crystallographically determined structures of three aspartyl proteases: penicillopepsin, endothiapepsin, and rhizopuspepsin. Using an algorithm in which a spherical probe approximating the size of the antibody-binding domain (1-nm radius) was allowed to contact the surface of the renin model, we predicted 12 to 15 peptides to be immunogenic epitopes. We synthesized peptides corresponding to three different regions of the model: Cys-Gly-Ser-Asp-Pro-Gln-His-Tyr-Glu-Gly-amide (C-180-188), Tyr-Leu-Leu-Cys-Glu-Asp-Gly-Cys-Leu-Ala-Leu-amide (Y-215-224; disulfide bond between cysteines) and Tyr-Gly-Ser-Ser-Thr-Leu-Leu-Cys-Glu-Asp-Gly-Cys-Leu-Ala-Leu-amide (Y-211-224; disulfide bond between cysteines), and Cys-Tyr-Ser-Ser-Lys-Lys-Leu-Cys-Gly (C-290-296-G; disulfide bond between cysteines). All four peptides were tested for their binding to 11 polyclonal and 7 monoclonal antibodies raised against pure human renin, in both a solution assay and an enzyme-linked immunosorbent assay. Peptides Y-215-224 and Y-211-224 bound to all 11 polyclonal antibodies in the solution assay, and peptide Y211-224 bound to eight of them in the enzyme-linked immunosorbent assay. Therefore, region 211-224 can be identified as a major epitope of the human renin molecule.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies↗

PubMed1986

Role of cyclic AMP in renin secretion by human transfected juxtaglomerular cells.

A human juxtaglomerular (JG) cell tumour was used for immortalization of renin secreting cells with three SV40 mutants. These transformed cells retained the same light and electron microscopic morphology as the human renal JG cells throughout subculture. Immunocytochemical staining showed the presence of renin in the elongated cells containing myofilaments and secretory granules. The renin produced was not stored within the cells but was released rapidly into the medium as prorenin. This permanent source of renin-producing cells was used for the study of renin regulation in vitro. Agents known to induce renin release such as dibutyryl cyclic AMP (cAMP), forskolin, isoproterenol and histamine were tested in cell culture. Forskolin induced renin secretion in a dose-dependent manner, as did dibutyryl cAMP. The JG cells responded to beta-agonists and to histamine by an H2 receptor. These results offer direct support for the hypothesis that cAMP is the second messenger in stimulation of renin secretion from human juxtaglomerular cells.

Bucladesine↗

PubMed1986

[Testing an expert system for hypertension].

An Expert System (ES) has been connected to a database management system for the management and follow-up of hypertensive patients. The patient data base, called Artemis, contains approximately 18,000 medical records. About 90% of the initial informations used by the ES is contained in the medical records of the Artemis data base. The knowledge base consists of 870 rules. A first group of rules allows the description of knowledge structures (hierachies, graphs and mutual exclusions). The second group consists of production rules which describe the dynamic reasoning of the expert. The inference engine uses a combination of forward and backward chaining. The ES produce diagnostic hypotheses (possible causes of hypertension) and therapeutic suggestions before and after requiring additional information (patient supplementary interrogation, biological or radiological investigations). The evaluation of the diagnostic performance of the ES was made on 40 confirmed cases of secondary hypertension (SH) and 40 cases of essential hypertension (EH). The initial initial diagnosis, just after the forward chaining step, was correct in 17 cases of SH and 32 cases of EH. The final diagnosis proposed after several steps of forward and backward chaining was correct in 37 cases (92%) of SH and 36 (90%) of EH. Averages of 5 (EH) and 8 (SH) questions were formulated by the ES to reach the final diagnosis. The integration of the ES to the database is expected to facilitate the validation of the knowledge base and to enhance its overall acceptability. Whether or not such an integration will be useful and accepted as a complementary tool by physicians remains however an open question.

Decision Making, Computer-Assisted↗

PubMed1986

[Reduction of urinary kallikrein in hypertensive diabetics].

Renal Kallikrein, an enzyme of the distal tubule acting through kinin liberation, may participate to the control of renal circulation and blood pressure. To study if an impairment of its secretion may exist in diabetics, a cross-sectional study was carried out on 40 non-hypertensive and 29 hypertensive diabetics, compared to 30-age related controls. Urinary Kallikrein Activity (UKA) was measured by its kininogenase activity with and without trypsin preincubation. Compared to UKA in controls (86 +/- 9 micrograms lysyl-bradykinin [LBK] produced per minute of incubation), UKA was significantly reduced either in non-hypertensive diabetics (59 +/- 8 micrograms LBK. min.-1; p less than 0.05) and in hypertensive diabetics (26 +/- 6 micrograms LBK. min.-1; p less than 0.001). The ratio of total/active urinary kallikrein was similar in diabetics and in controls. The decline of UKA in diabetics was related to the duration of their disease (r = -0.38; p less than 0.05) and to their stage of retinopathy (r = -0.46; p less than 0.001). UKA values were proportional to creatinine clearance in diabetics (r = 0.58; p less than 0.001). The lowest UKA values were found in patients with a high urinary excretion of albumin (above 500 mg/day): 8 +/- 2 micrograms LBK. min-1 (p less than 0.001) and beta-2-microglobulin (above 382 micrograms/day): 12 +/- 4 micrograms LBK. min-1 (p less than 0.001). These findings support that an impaired secretion of renal kallikrein in diabetics can be related to the duration of diabetes and to the severity of microangiopathy.

Adult↗

PubMed1986

[Comparison of ambulatory blood pressure determinations using the Remler and Spacelabs devices].

Ambulatory blood pressure recorded with the Spacelabs was compared with both Remler recordings and office blood pressures in 11 normotensive and 13 hypertensive volunteers. Analysis of 324 simultaneous measurements with Remler and Spacelabs showed very high correlation for systolic and for diastolic blood pressure. For systolic blood pressure, measurements with Spacelabs recorder were lower than those with the Remler recorder by a mean of 3.6 +/- 6.5 mmHg, principally in hypertensive subjects. Spacelabs measurements were also lower than Remler measurements for diastolic blood pressure by a mean of 5.3 +/- 6.6 mmHg principally in normotensive subjects. The averages of blood pressure variability (standard deviation as index) recorded by each device were identical. Mean systolic and diastolic blood pressure differed by more than 10 and 5 mmHg respectively between the two devices in 11 and 83% of the subjects. These individual discrepancies were unpredictable. Comparison of Spacelabs records with office blood pressure measured with a standard mercury manometer showed discrepancies of more than 10 mmHg for systolic blood pressure and more than 5 mmHg for diastolic blood pressure in 46 and 42% of the 24 subjects, respectively. These discrepancies could be due, in part, to different methods of blood pressure measurements. These data demonstrate that the Spacelabs apparatus provides records for a group, reasonably close to those obtained with the Remler over a wide range of blood pressure. For the management of hypertension, the advantages--as compared to physician's measurements--of ambulatory blood pressures recorded with indirect methods,need to be weighed, taking into consideration the difference between the ambulatory record and the office blood pressure measured with the same device.

Blood Pressure↗

PubMed1986

[From the renin gene to renin inhibitors].

The only known action of renin is the hydrolysis of angiotensinogen into angiotensin I. Renin is synthesized as an inactive precursor, preprorenin. The processing of prorenin into active renin occurs after the clivage of a profragment, just after a dibasic pair of amino-acids. The renin profragment hinders the active site by its binding to the rest of the molecule. Circulating inactive renin is prorenin because it is recognized by antibodies produced against various parts of the renin profragment. Renin, like other aspartyl proteases, hydrolyses its substrate in its active center where two aspartyl residues are involved in the catalytic mechanism. The strong species specificity of renin lies in its interaction with its substrate through subsites which can be modelized by computer graphics. There is much promise in the inhibition of the renin angiotensin system at the level of the renin-angiotensinogen reaction. The i.v. infusions of human renin antibodies in primates produces a decrease in blood pressure which is parallel to that observed during inhibition of the angiotensin I converting enzyme. The magnitude of the blood pressure decrease depends on the intensity of the sodium depletion. Potent and specific pepstatin derived inhibitors have been synthesized which are able to inhibit primate renin in vitro and in vivo with a long duration of action. Other transition state analogs inhibitors have been administered parenterally in humans and similar results have been obtained. The concept of the treatment of hypertension by an anti-renin drug is becoming more and more a reality. However, it remains to find an orally active and a non-toxic compound which will compare well with the present converting enzyme inhibitors.

Animals↗

PubMed1985

Systemic hypertension after cardiac transplantation: effect of cyclosporine on the renin-angiotensin-aldosterone system.

Fifteen patients who had undergone cardiac transplantation and who had hypertension (164 +/- 14/112 +/- 13 mm Hg), aged 16 to 57 years (mean 39), were treated with cyclosporine, 8 +/- 3 mg/kg/day, and prednisolone, 0.27 +/- 0.1 mg/kg/day, for 63 to 788 days (mean 288) after transplantation. They were not given antihypertensive drugs. Before treatment, the mean urinary sodium level was 104 +/- 48 mEq/day. Two discrete abnormalities accompanied their high blood pressure (BP): an increase in serum creatinine levels (p less than 0.05) to values exceeding those measured just before transplantation (2.1 +/- 1.0 vs 1.35 +/- 0.54 mg/dl) with low creatinine clearance (61 +/- 28 ml/min X 1.73 m2), and a 15% increase in plasma volume (+445 +/- 686 ml, p less than 0.02). Urinary excretion of vanilmandelic acid and total metanephrines was normal. Supine plasma renin activity was also normal (0.78 +/- 0.32 nmol/ml/hour). The stimulation of renin release after acute inhibition of converting enzyme by captopril was less marked than is usual in hypertensive subjects (0.86 +/- 0.54 nmol/liter/hour). Captopril induced a smaller drop in BP than nifedipine (-8 +/- 13/-6 +/- 10 mm Hg vs -14 +/- 11/-15 +/- 10 mm Hg). Levels of plasma aldosterone, angiotensinogen and converting enzyme activity were all normal, 308 +/- 147 pmol/liter, 712 +/- 164 nmol/ml and 30 +/- 6 mU/ml, respectively. It is concluded that hypertension is common in cardiac transplantation patients treated with cyclosporine, since 13 of our 15 subjects were normotensive before transplant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1985

A study of the renin inhibitor H142 in man.

The inhibitor of human renin, H142, was studied in nine male volunteers. On three occasions, in random order, volunteers were infused with 5% dextrose or with H142 at 1.0 or 2.5 mg/kg per h for 30 min while supine and thereafter with dextrose for 1 1/2 h. There was a marked reduction in plasma active renin concentration as assayed by an enzyme-kinetic method, with parallel falls in the circulating concentrations of angiotensins (ANG) I and II, all of which rebounded transiently to values above basal after the H142 infusion was stopped. In contrast, total renin concentration as measured by radio-immunoassay rose while ANG I and II fell, subsiding when H142 was discontinued. There was a slight but significant increase in plasma noradrenaline as renin became inhibited; plasma adrenaline was unchanged. H142 produced a slight fall in systolic blood pressure (SBP) and a clearer, highly significant, dose-related fall in diastolic blood pressure (DBP). There was a modest but significant increase in the heart rate. These studies confirm H142 as an effective inhibitor of human renin in vivo.

Adult↗

PubMed1985

Immunocytochemical localization of renin in juxtaglomerular cells.

The involvement of various organelles in the synthesis, transport, and packaging of renin in the juxtaglomerular cells of newborn mice has been investigated by immunocytochemistry with the protein A-gold technique. Highly specific rabbit antibodies against mouse submandibular renin were used. Mild fixation and embedding in glycol methacrylate allowed enough sensitivity to identify a steep gradient of labeling from rough endoplasmic reticulum to Golgi complex to secretory granules. Routine fixation and embedding in Epon produced labeling differentials that allowed delineation of hitherto ill-defined types of secretory granules and vacuoles. The classical pattern of synthesis, transport, and packaging of secretory proteins involves the rough endoplasmic reticulum and Golgi complex and seems to apply to renin secretion. Immunoreactive renin is packaged as rhomboid crystals at the trans face of the Golgi complex. The limiting membrane of these rhomboids fuses to form coalescing protogranules where the crystals eventually yield their individuality maturing into secretory granules. Vacuoles containing a flocculent material, with or without a dense core, show significant immunocytochemical labeling. These vacuoles are not associated with the Golgi complex but occupy cytoplasmic areas well endowed with rough endoplasmic reticulum. As judged from their morphological features and their immunoreactivity, the vacuoles do not seem to follow the sequence of events typical of protogranules and coalescing protogranules. They possibly represent a parallel pathway of renin synthesis and transport, involving the nuclear envelope and bypassing the Golgi complex.

Animals↗