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Biomedical subjects

J Camps

Publications and source records attributed to J Camps.

At least 127 records · Page 7Linked to original sources
PubMed1989

Short-term and long-term changes of left ventricular volumes during rate-adaptive and single-rate pacing.

To evaluate the adaptation of the heart to exercise during pacing, 15 patients with permanent endocardial pacemakers were studied; nine patients had atrioventricular universal (DDD) pacemakers (Symbios 7005) and six patients had activity detecting rate-responsive ventricular (VVIR) pacemakers (Activitrax 8403). Left ventricular function in each patient during rate variable pacing was compared to ventricular function during VVI single-rate pacing. End-systolic and end-diastolic volume changes during exercise were measured by radionuclide angiography and the amount of volume change was used to assess left ventricular function. Both short-term (within 4 hours) and long-term measurements (after at least 4 weeks) were made at rest and at 50% of the maximal exercise capacity in DDD or VVIR mode and were compared with VVI single-rate pacing. All patients, when changed from DDD or VVIR mode to VVI single-rate pacing showed a significant increase of the end-diastolic volume during exercise, which increased even more after long-term VVI pacing. During long-term rate variable pacing, there was no increase of the end-diastolic volume during exercise. DDD or VVIR pacing initially showed a substantial increase of the end-systolic volume during exercise combined with a decrease of left ventricular ejection fraction, suggesting a decrease of the left ventricular contractility. After 4 weeks, contractility improved both with DDD and VVIR pacing. We conclude that short-term DDD and VVIR pacing induces a temporary impairment of left ventricular function that improves after 4 weeks, whereas long-term VVI pacing is associated with left ventricular dilatation even at moderate levels of exercise.

Adaptation, Physiological↗
PubMed1989

[Comparative test of the malleability of three gutta-perchas].

The obturation of a prepared canal consisting in molding a gutta-percha cone, in order to spread against the canal wall, the authors tested the malleability of three brands of gutta-percha. The study points out the superiority of the brand "Hygienic", and the different underpressure characteristic related to the speed of compression.

Elasticity↗
PubMed1989

["Endo-prosthetic" preparation of curved roots].

During the tooth preparation for root posts, all must be attempted to avoid weakening of the root. This "must" is rather easy for straight roots, but the same is not true of curved roots. The authors have used the method described by BRAMANTE et al. to study the effects of various techniques of instrumental sequences of endodontic preparation, and of two instrumental sequences of root post preparation. From this studies, it results that: --the respect of the canal path during the endodontic phase conditions the respect of the internal wall of the curvature, during drilling. --among the four endodontic techniques studied: MM 3000, Step-Back, Anti Curvature Filling and Canal Finder System, the last two seem to allow more respect of the canal path. --the instrumental sequence using Largo drills to prepare a canal, presents two types of drawbacks: * Excessive abrasion of the convex (internal) wall of the canal system. It seems that the blunt point rests against the concave portion of the canal and pushes the drill toward the internal wall, therefore weakening it. * Inadequate match between the size of the drill and that of the prepared canal. --the Parapost drills, on the contrary, respect the endodontic path, and may even be used beyond the curvature (2 mm). Besides, the diameter of the prepared canal is similar to that of the instrument used. These two factors permit to obtain a better retention of the post as well as a lesser weakening of the root.

Dental Pulp Cavity↗
PubMed1988

Prostaglandin precursor fatty acids in cirrhosis with ascites: effect of linoleic acid infusion in functional renal failure.

1. Functional renal failure (FRF) in cirrhosis with ascites could be related to an inappropriately low renal prostaglandin (PG) production. To investigate whether the impaired renal PG synthesis in these patients is related to a PG precursor fatty acid deficiency, serum levels of linoleic and arachidonic acids and the urinary excretion of PGE2, 6-keto-PGF1 alpha and thromboxane B2 (TxB2) were measured in 10 normal subjects, 17 non-azotaemic cirrhotic patients with ascites and 10 cirrhotic patients with ascites and FRF. 2. Serum linoleic acid levels were similar in the three groups studied. Both groups of cirrhotic patients showed lower arachidonic acid levels than normal subjects; however, non-azotaemic cirrhotic patients and patients with FRF did not differ in relation to serum arachidonic acid. 3. Non-azotaemic cirrhotic patients had higher urinary PGE2, 6-keto-PGF1 alpha and TxB2 excretion than normal subjects and cirrhotic patients with FRF. Patients with FRF showed similar urinary PGE2 and TxB2 and lower urinary 6-keto-PGF1 alpha than normal subjects. In all cirrhotic patients no significant correlation was found between serum linoleic and arachidonic acid levels and urinary PGs. 4. In seven patients with FRF an acute intravenous infusion of linoleic acid induced a marked increase in serum levels of this fatty acid. However, no increase in serum arachidonic acid levels and urinary PG excretion and no improvement in renal function was observed. 5. This study suggests that an arachidonic acid deficiency is present in cirrhotic patients with ascites but that this abnormality is not a major determinant of renal function and PG production in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Longitudinal study of renal prostaglandin excretion in cirrhotic rats: relationship with the renin-aldosterone system.

1. A cross-sectional study (protocol A) was performed in 19 rats with cirrhosis, induced by carbon tetrachloride (CCl4), and ascites and in 10 control animals to assess renal prostaglandin (PG) excretion in experimental cirrhosis. In an additional group of animals, including nine rats chronically exposed to CCl4 (CCl4 rats) and six control rats, a longitudinal study (protocol B) was performed to investigate the temporal relationship between changes in renal PG excretion, the renin--aldosterone system and renal function. 2. Urinary PG excretion was assessed by specific radioimmunoassay of PGE2, PGF2 alpha, 6-keto-PGF1 alpha and thromboxane (TX) B2 after extraction with octadecyl silica cartridges and h.p.l.c. purification. Recoveries for each prostanoid (61 +/- 8% for PGE2, 64 +/- 12% for PGF2 alpha, 65 +/- 11% for 6-keto-PGF1 alpha and 66 +/- 17% for TXB2) were determined in every sample by adding tritiated standards, and the final values were corrected according to the individual recoveries. 3. Cirrhotic rats with ascites in protocol A showed a significantly higher plasma renin and aldosterone concentrations and urinary excretion of 6-keto-PGF1 alpha and TXB2 than did control animals. Urinary excretion of PGE2 and PGF2 alpha, however, was significantly reduced in cirrhotic animals as compared with controls. 4. In CCl4 rats included in protocol B, there was a close chronological relationship between the activation of the renin-aldosterone system, as estimated by urinary aldosterone excretion, the onset of sodium retention and the increase in urinary excretion of 6-keto-PGF1 alpha and TXB2. The urinary excretion of PGE2 and PGF2 alpha in CCl4 rats was reduced throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1988

Urine ethanol assessment: a helpful method for controlling abstinence in alcoholic liver disease.

The usefulness of a urine-alcohol determination in the evaluation of abstinence in alcoholic liver disease has been investigated in 181 patients. Alcohol was tested in morning urine samples collected on a follow-up visit in 103 patients, and the results were compared with those in 78 patients, where three samples were collected within the same week; one in the morning and two in the evening. Although the percentage of urine samples containing alcohol measured in a morning sample was similar to the patients' self-report (31% and 34%, respectively), urine analysis identified an additional 7% of patients who denied alcohol intake. Alternatively, serial urine-alcohol determinations were significantly more effective than patient reports (54% and 35.9%, respectively, P less than 0.01), particularly when urine was collected in the evenings. This difference was due mainly to the reluctance of women to admit drinking (7.4% of positive self reports vs 51% of women with alcohol positive urine samples, P less than 0.001). We conclude that serial measurements of alcohol in urine were useful tests which should be used to complement personal interview in the control of abstinence in patients with alcoholic liver disease.

Ethanol↗
PubMed1987

Temporal relationship between the impairment of free water excretion and antidiuretic hormone hypersecretion in rats with experimental cirrhosis.

To investigate the temporal relationship between the impairment of water excretion, sodium retention, and antidiuretic hormone hypersecretion in cirrhosis, free water excretion (estimated by the minimum urinary osmolality) and urinary antidiuretic hormone excretion (which correlates with the plasma levels of this hormone) were measured weekly after an oral water load in 18 rats with carbon tetrachloride-induced cirrhosis and in 20 control animals. The onset of ascites (as an index of sodium retention) in cirrhotic rats was estimated by sequential paracentesis. Thirteen cirrhotic animals developed an impairment of water excretion 2-5 wk after the onset of ascites. The urinary excretion of antidiuretic hormone in these animals, which was normal before the impairment of water excretion, increased markedly within the week in which this abnormality was first detected and remained high thereafter. The remaining 5 cirrhotic rats did not experience an impairment of free water excretion in spite of developing ascites. The urinary excretion of antidiuretic hormone in these animals was similar to that of control rats during the entire study. In all urine samples obtained from cirrhotic rats, there was a highly significant direct linear correlation between the urinary excretion of antidiuretic hormone and the minimum urinary osmolality. Our results show the following: in rats with carbon tetrachloride-induced cirrhosis, sodium retention preceded the impairment of water excretion; and in these animals, the defect in water metabolism correlated chronologically and quantitatively with antidiuretic hormone hypersecretion. These findings are consistent with the concept that antidiuretic hormone is a major determinant of the impaired water metabolism in cirrhosis.

Animals↗
PubMed1987

Comparison of paracentesis and diuretics in the treatment of cirrhotics with tense ascites. Results of a randomized study.

To investigate whether paracentesis could be an alternative therapy for ascites, 117 cirrhotics with tense ascites were randomly allocated into two groups. Fifty-eight patients (group 1) were treated with paracentesis (4-6 L/day until disappearance of ascites) and intravenous albumin infusion (40 g after each tap). Fifty-nine patients (group 2) were treated with spironolactone (200-400 mg/day) plus furosemide (40-240 mg/day). Patients from group 2 not responding to diuretics were treated with a LeVeen shunt. After disappearance of ascites, patients from both groups were discharged from hospital and were instructed to take diuretics. Patients developing tense ascites during follow-up were readmitted to hospital and treated according to their initial schedule. Paracentesis was effective in eliminating the ascites in 56 patients from group 1 (96.5%) and did not induce significant changes in renal and hepatic function, plasma volume, cardiac index, peripheral resistance, plasma renin activity, plasma norepinephrine and antidiuretic hormone concentration, and urinary excretion of prostaglandin E2 and 6-keto-prostaglandin F1 alpha. Diuretics were effective in eliminating the ascites in 43 patients from group 2 (72.8%) (p less than 0.05). Ten patients in group 1 and 36 in group 2 developed complications during their first hospital stay (p less than 0.001). This difference was due to the significantly higher incidence of hepatic encephalopathy, renal impairment, and electrolyte disturbances occurring in patients treated with diuretics. The duration of hospital stay was 11.7 +/- 1.5 days for patients from group 1 and 31 +/- 2.8 days for patients from group 2 (p less than 0.001). The two groups did not differ significantly with respect to the probability of requiring readmission to hospital during follow-up, reasons for readmission, survival probability after entry into the study, and causes of death. These results indicate that paracentesis associated with intravenous albumin infusion is a fast, effective, and safe therapy for ascites in patients with cirrhosis.

Albumins↗
PubMed1986

Exercise testing and thallium-201 myocardial perfusion scintigraphy in the clinical evaluation of patients with Wolff Parkinson White syndrome.

In 58 patients with Wolff Parkinson White syndrome (WPW), we performed exercise stress testing in order to investigate the incidence of normalization of the auriculo-ventricular conduction and the ST-segment changes. For a more accurate evaluation of the latter, exercise and redistribution radionuclide images with Thallium-201 were obtained in 18 cases. Forty-nine had type A and nine had type B of WPW. Forty-eight had permanent, four had alternant and six had no pre-excitation (PE) when they started the test. Mean maximal functional capacity, mean maximal heart rate and mean maximal double product were not different when compared to an age-matched control group. Of the 48 patients who began the test with PE, in 23 (48%) it disappeared while PE persisted in 25 (52%). In 16 cases the disappearance of the PE was sudden and in seven it was progressive. Pre-excitation persisted in 39.5% of patients with type A and in 88.8% with type B (p less than 0.01). ST-segment depression was observed in 76.6% of patients with PE and in 28.6% of cases without PE (p less than 0.01). ST-segment depression occurred in 44.8% of patients with type A and in 100% of cases with type B (p less than 0.05). Transient abnormal Thallium-201 scans were observed in 62.5% of patients without PE and in 20% with PE. No patients showed exertional arrhythmias. This study suggests the possibility of measuring the duration of the refractory period of the accessory pathway in those patients in which the PE disappears suddenly, at a given heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Urinary excretion of 6-keto-prostaglandin F1 alpha, thromboxane B2 and prostaglandin E2 in cirrhosis with ascites. Relationship to functional renal failure (hepatorenal syndrome).

The aim of the study was to investigate the urinary excretion of 6-keto-PGF1 alpha (a stable metabolite of PGI2), thromboxane B2 (TxB2; a stable metabolite of TxA2), and PGE2 in 18 normal subjects, 49 cirrhotics with ascites without renal failure (GFR = 90 +/- 4 ml/min, means +/- S.E.M.) and 20 cirrhotics with functional renal failure (FRF) (GFR = 36 +/- 3). The study was made after 5 days on a 50 mEq sodium diet and without diuretics. Plasma renin activity (PRA), plasma norepinephrine concentration (NE) and plasma antidiuretic hormone concentration (ADH) were also measured. Cirrhotics without FRF showed a significantly higher urinary excretion of 6-keto-PGF1 alpha, TxB2 and PGE, (15.9 +/- 1.7 ng/h, 3.0 +/- 0.3 ng/h, and 6.2 +/- 1.0 ng/h) than did normal subjects (9.2 +/- 0.9, 1.3 +/- 0.1 and 2.3 +/- 0.4). On the contrary, the urinary excretion of these prostaglandins was normal or reduced in patients with FRF (5.3 +/- 0.8, 1.3 +/- 0.2 and 1.9 +/- 0.4). PRA, NE and ADH were significantly increased in cirrhotics with FRF (15.2 +/- 3.9 ng/ml/h, 1026 +/- 149 pg/ml and 4.1 +/- 0.3 pg/ml) and in patients without FRF (8.0 +/- 1.4, 667 +/- 67 and 3.9 +/- 0.3) as compared to normal controls (1.3 +/- 0.2, 275 +/- 46 and 2.4 +/- 0.2). These results suggest that renal hemodynamics in cirrhosis depends upon a critical equilibrium between the activity of endogenous vasoconstrictor systems and the renal production of the vasodilator prostaglandins PGI2 and PGE2. In addition, they do not support FRF in cirrhosis being related to an increased renal production of the vasoconstrictor prostaglandin TxA2.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Sulindac reduces the urinary excretion of prostaglandins and impairs renal function in cirrhosis with ascites.

In 5 patients with cirrhosis and ascites the glomerular filtration rate (GFR), free water clearance (CH2O) and urinary excretion of prostaglandin E2(PGE2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) were measured before and after a 3-day treatment with sulindac (400 mg/day). The administration of sulindac induced a marked fall of urinary excretion of PGE2 (from 24.2 +/- 5.5 to 3.8 +/- 1.1 ng/h; p less than 0.05), 6-keto-PGF1 alpha (from 19.9 +/- 2.9 to 5.6 +/- 1.1 ng/h; p less than 0.02) GFR (from 111 +/- 15 to 67 +/- 10 ml/min; p less than 0.01) and CH2O (from 7 +/- 1.5 to 3.7 +/- 1.3 ml/min; p less than 0.02) in all patients studied. The plasma concentration of the active metabolite sulindac sulfide in cirrhotics was 400% of that found in 6 healthy volunteers (9.6 +/- 1.7 vs. 2.4 +/- 0.6 ng/ml). Our results indicate that sulindac, at a dose of 400 mg/day, inhibits the renal synthesis of prostaglandins and impairs renal function in cirrhotics with ascites. These effects are probably related to the marked alteration of sulindac kinetics that occurs in these patients.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

[Technics for the study of the renal excretion of free water in normal rats and those with experimental liver cirrhosis].

Different techniques to measure free water excretion in rats, administered an oral water overload and with measurement of its ability to excrete it into the urine have been studied. When 30 or 50 ml/kg b.wt. were administered and the urine excreted in 3 h was collected, a decrease on the urinary osmolality (UOSM) was observed with respect to the baseline UOSM, which was similar in both overloads, although the percentage of the overload excreted was significantly greater with 50 ml/kg. However, the UOSM obtained was hypertonic as compared to plasma osmolality (POSM) indicating that this determination was not useful to study free water excretion. In a further study it was investigated if there was any period of time in which all the animals excreted hypotonic urine. However, results indicated that the period for excreting a maximally diluted urine was very variable in time. The best technique to study free water excretion in these animals was the collection of each spontaneously voided urine independently, to measure the minimal UOSM. When a 50 ml/kg water load was administered and the minimal UOSM was determined it was observed to be lower than POSM in all the animals indicating that this technique was useful to study this derangement in these animals.

Animals↗
PubMed1986

[Determination of arginine-vasopressin in small volumes of rat plasma].

A radioimmunoassay to determine arginine-vasopressin concentration in rat plasma is described. This method was a modification from a previously described technique from which the incubation volume was reduced. It allows us to use only 300 microliter of plasma, 1/4 of the original volume, without any impairment to the sensitivity. The intra- and inter-assay coefficients of variation are 11% and 13% respectively. The accuracy ranges between 90 and 99%. To investigate the influence of sampling blood conditions on arginine-vasopressin levels, five groups of Sprague-Dawley rats are analyzed: Group I, decapitation; Group II, ether anaesthesia and cardiac puncture; Group III, ether anaesthesia and decapitation; Group IV, ketamine anaesthesia and cardiac puncture; Group V, ketamine anaesthesia and decapitation. Arginine-vasopressin levels in Group V (2.2 +/- 0.8 pg/ml) are significantly lower than those from the other four groups and similar to those obtained by other authors using a chronic catheter.

Animals↗
PubMed1985

Renal hemodynamic abnormalities in patients with short term insulin-dependent diabetes mellitus: role of renal prostaglandins.

To determine if renal functional alterations in diabetes mellitus could be related to disturbances of vasoactive systems, renal plasma flow (RPF), glomerular filtration rate (GFR), PRA (basal and stimulated), plasma catecholamine levels, and urinary excretion of prostaglandin E2 (PGE2), 6-keto-PGF1 alpha, and kallikrein were determined in 21 patients with insulin-dependent diabetes mellitus (IDDM) of short duration and 15 normal subjects. In 7 additional patients with IDDM and in 4 normal subjects, the effect of lysine acetylsalicylate (LAS; 450 mg, iv) on GFR and RPF was studied. Patients with IDDM had higher RPF and GFR than normal subjects. Plasma norepinephrine and basal and stimulated PRA were significantly lower in IDDM than in the control group [161 +/- 82 (+/- SD) vs. 243 +/- 114 pg/ml, 0.19 +/- 0.20 vs. 1.15 +/- 0.33 ng/ml X h, and 0.93 +/- 0.82 vs. 2.8 +/- 1.73 ng/ml X h, respectively). No significant differences were found in the urinary excretion of PGE2, 6-keto-PGF1 alpha, and kallikrein in the two groups. LAS administration significantly reduced RPF (from 641 +/- 72 to 535 +/- 38 ml/min X 1.73 m2) and GFR (from 168 +/- 25 to 150 +/- 18 ml/min X 1.73 m2) in patients with IDDM, but not in normal subjects. In IDDM patients, there was a close direct correlation between the percent decrease in RPF and GFR induced by LAS and the baseline values of these parameters. The results suggest that in IDDM, there may be an imbalance between the degree of activation of the renin-angiotensin and sympathetic nervous systems and the renal production of PGs. The observation that LAS administration reduced RPF and GFR in these patients suggests that renal PGs are involved in the renal hyperperfusion of IDDM.

Adult↗