[Effect of finasteride on the percentage of free PSA: implications in the early diagnosis of prostatic cancer]

OBJECTIVE

To analyze the behaviour of free PSA percentage in finasteride-treated patients and to evaluate whether this ratio allows an increased PSA specificity in the early diagnosis of prostate cancer.

MATERIAL AND METHODS

Evaluation of PSA serum levels and free PSA ratio in 336 patients initially diagnosed with prostate benign hyperplasia (PBH). A group of 82 patients were treated with finasteride for 14 to 58 months. A second group of 254 patients received no treatment. All patients were within the same age range and had similar PSA serum levels. In total, 141 prostate biopsies were performed: 19.5 (16/82) and 49.1 (125/254) respectively.

RESULTS

Median PSA level in PBH patients was 1.6 ng/mL for the finasteride-treated group and 3.5 for the untreated group, p < 0.0001. Free PSA ratio was 18.6 and 18.8%, respectively, p > 0.05. Carcinoma detection rate was 25% (4/16) for the finasteride group and 27.2% (34/125) for the untreated group. If biopsy had been requested when PSA percentage was below 25%, 17.7 and 19.8% respectively would have been prevented and all carcinoma detected.

CONCLUSION

Long-term treatment with finasteride reduces PSA serum concentration about 50% without changing the free PSA ratio. Carcinoma detection rate was similar in finasteride-treated and untreated patients. Free PSA ratio allows to increase PSA specificity and avoid unnecessary biopsied also in finasteride-treated patients.

Blood bank leukocyte infusions as remission induction therapy in a case of acute lymphoblastic leukemia

A 15-year-old female with pre-pre B ALL in third relapse was treated with administration of eight blood bank leukocyte concentrates per day for 5 days. The total number of mononuclear cells per kilogram of weight was 4.89 x 10(8). On the fifth day of infusions the patient was in complete remission (CR), asymptomatic and with a normal CBC. No secondary effects were found. The patient remained in CR without treatment for 10 weeks before relapsing again. The possibility of reaching a short-lived, clinically relevant response, using blood bank leukocyte infusions, is a promising new approach for the treatment of leukemia.

Relationship between viral genotype and viral load in patients with chronic hepatitis C

To determine the distribution of hepatitis C virus (HCV) genotypes and to related genotype to viral load, genotyping and quantification of viral RNA were carried out in 35 patients with chronic hepatitis C. Subtype 1a was most prevalent (43%), followed by subtypes 1b (23%) and 3a (14%). Mean viral load (log HCV-RNA copies/ml) for subtypes 1b, 1a and 3a was 7.1 +/- 1, 5.6 +/- 1.1 and 4.1 +/- 2.4, respectively. The presence of immunoglobulin M was related to the duration of hepatitis and genotype 1 to a more severe hepatic injury and higher viral load. Differences observed in viral load for a single HCV subtype justify the need to quantify HCV-RNA prior to establishing antiviral therapy.

Impairment of intracellular calcium homoeostasis in the exocrine pancreas after caerulein-induced acute pancreatitis in the rat

1. We have measured intracellular calcium concentrations in basal conditions and in response to cholecystokinin-octapeptide and acetylcholine in pancreatic acini isolated from rats with caerulein-induced acute pancreatitis and compared them with those in control rats. 2. We also measured amylase secretion in basal conditions and in response to cholecystokinin-octapeptide in both groups. 3. In pancreatic acini from rats with pancreatitis the basal intracellular calcium concentration was significantly increased (134.9 +/- 7.1 nmol/l compared with 71.8 +/- 2.9 nmol/l, P < 0.001). Moreover, the maximum values of intracellular calcium attained during the stimulation period were equivalent in acini from control and pancreatitic rats with no statistically significant differences. 4. In acini from control rats the differences between the resting levels of intracellular calcium and the maximum intracellular calcium values (delta[Ca2+]i) in response to several concentrations of cholecystokinin-octapeptide showed a clear dose-response relationship, with a half-maximal increase at 0.1 nmol/l and a maximal difference (delta[Ca2+]i = 259 +/- 50 nmol/l) at 1 nmol/l. In contrast, a right-shifted response, with a statistically significant smaller increase, was observed in acini from pancreatitic rats. 5. Basal amylase release was significantly higher in acini from rats with pancreatitis (11.7 +/- 1.0% of total compared with 5.9 +/- 1.1% of total, P < 0.001). In contrast, cholecystokinin-octapeptide and acetyl-choline-evoked amylase secretion was reduced by more than 85% in acini from pancreatitic rats. 6. In conclusion, calcium homoeostasis in pancreatic acinar cells from rats with caerulein-induced pancreatitis seems to be impaired. These results suggest excessive release of acinar free ionized calcium, or damage to the integrity of mechanisms that restore low resting levels of intracellular free ionized calcium, and the consequent calcium toxicity could be the key trigger in caerulein-induced acute pancreatitis.

Dose-response effects of VIP on the rabbit exocrine pancreatic secretion. Comparison with PACAP-27 actions

A dose-response study of the effects of vasoactive intestinal peptide (VIP) on the exocrine pancreatic secretion of the rabbit has been made. Furthermore, the actions of VIP and pituitary adenylate cyclase activating peptide (PACAP) on the exocrine pancreatic secretion were compared at a similar molar dose. After the infusion of VIP a linear dose-response relationship for pancreatic flow rate and bicarbonate output, up to the dose of 4 micrograms/kg, was observed. VIP acts as a partial agonist of secretin, the rabbit pancreas being less sensitive to VIP compared with other mammals. Moreover, VIP did not significantly stimulate the pancreatic protein output. PACAP stimulated the hydroelectrolyte fraction of the exocrine pancreatic secretion in a similar manner to that of VIP. Unlike what was observed with VIP, PACAP, on the same molar basis, significantly stimulated the protein and amylase outputs. Furthermore, PACAP releases VIP, so that the action of PACAP on the hydroelectrolyte fraction may be partially mediated by VIP; on the other hand, VIP is not involved in the effect of PACAP on the pancreatic enzyme secretion of this species.

Cholinergic pathways are involved in secretin and VIP release and the exocrine pancreatic response after intraduodenally perfused acetic and lactic acids in the rat

The response of the exocrine pancreas to intraduodenal perfusion of acetic and lactic acids in normal and previously atropinized rats was studied. Secretin and vasoactive intestinal peptide (VIP) plasma levels in portal plasma were also measured. Intraduodenal perfusion of both acetic and lactic acids significantly stimulated flow rate (from 0.29 +/- 0.03 microliters/min to a maximum of 1.06 +/- 0.08 microliters/min after acetic and from 0.35 +/- 0.05 microliters/min to a maximum of 1.13 +/- 0.12 microliters/min after lactic acid perfusion) and protein output (from 11.16 +/- 2.33 micrograms/min to a maximum of 35.1 +/- 7.4 micrograms/min after acetic and from 8.98 +/- 0.95 micrograms/min to a maximum of 22.5 +/- 1.3 micrograms/min after lactic acid perfusion). Atropine treatment significantly inhibited pancreatic flow rate and protein output after acetic acid perfusion, but no inhibition of flow rate and a slight decrease in the protein output after lactic acid perfusion were seen. With respect to plasma peptide concentrations, significant increases in secretin and VIP levels were found after perfusion of both organic acids; atropine administration significantly decreased plasma secretin levels after acetic acid administration although it did not affect plasma VIP concentrations. By contrast, atropine significantly increased plasma secretin levels, but significantly lower values of plasma VIP concentrations were observed after lactic acid perfusion. Therefore, cholinergic mechanisms are involved in the release of secretin and VIP and different types of control of exocrine pancreatic secretion occur, depending on the features of the intraduodenal stimulant.

Effects of acute intravenous ethanol on basal exocrine pancreatic secretion in rat: cholinergic involvement

The effect of intravenous infusion of ethanol on the basal exocrine pancreatic secretion of anesthetized rats was studied. The cholinergic involvement on the actions of ethanol was also studied using previously atropinized animals. During the stimulation period, pancreatic flow rate was significantly increased by intravenous ethanol in both un-atropinized (199% compared with basal) and atropinized rats (195% compared with basal). Pancreatic protein output was also increased during ethanol administration in both groups of animals (171% and 165% compared with basal in, respectively, un-atropinized and atropinized rats). After the administration of ethanol, in the poststimulation period, pancreatic flow rate was further increased only in the atropinized group of rats (290% compared with basal), whose values were significantly higher than those of ethanol-treated un-atropinized animals (195% compared with basal). A similar profile of response was observed in pancreatic protein output. Since intravenous ethanol did not stimulate either secretin or VIP release to portal plasma, the present results point to a direct effect of this substance on the exocrine pancreas. Furthermore, atropine revealed the existence of an inhibitory cholinergic effect of ethanol on the exocrine pancreas. In summary, results show that the effect of intravenous ethanol on the basal exocrine pancreatic secretion is dual and antagonistic.

Comparison between the effects of VIP and the novel peptide PACAP on the exocrine pancreatic secretion of the rat

The effect of intravenous infusion of pituitary adenylate cyclase-activating peptide (PACAP) 27, a novel regulatory peptide that shows a close structural and chemical similarity to vasoactive intestinal peptide (VIP), on the rat exocrine pancreatic secretion was studied. PACAP and VIP stimulated the flow rate of exocrine pancreatic secretion (p < 0.05). However, protein output and amylase secretion were mainly stimulated by PACAP. Intravenous infusion of VIP increased the plasma levels of secretin (p < 0.05). On the other hand, PACAP released neither secretin nor VIP. Our results show: (a) both PACAP and VIP stimulate exocrine pancreatic secretion, (b) PACAP stimulation of pancreatic amylase and protein secretion is greater than that induced by VIP, and (c) PACAP probably exerts a direct effect on exocrine pancreas whereas some of the actions of VIP might be mediated by secretin.

[Complications of laparoscopic surgery in urology]

More and more laparoscopic procedures are performed in Urology each day. Attempts at reducing the invasiveness of conventional surgical procedures and the possibility of permitting patients to resume their activities earlier have considerably extended the indications for laparoscopy. Laparoscopic access to the urinary system is not simple since it is almost completely located in the retroperitoneal region and peritoneal insufflation with CO2 puts organs that were previously protected within the abdominal cavity at risk. The urologist must operate in a surgical field that was previously unfamiliar to him, with no stereoscopic vision and using instruments without all of the functions of those of conventional surgery. The complications of laparoscopic surgery may present intraoperatively or late postoperatively. Correct patient selection and preparation can prevent many of the complications that arise during trocar insertion. The physiological response to peritoneal insufflation with CO2 must be well understood if the possible complications arising from pneumoperitoneum are to be prevented or correctly treated. The different complications of laparoscopic surgery in Urology are described. The potential problems of the different stages of the procedure, the pathophysiological aspects, prevention and treatment are discussed.

Mechanisms involved in the control of exocrine pancreatic secretion in the interdigestive state in the rabbit

The effect of rapid wash-out of the duodenum with phosphate buffered saline on exocrine pancreatic secretion and plasma levels of secretin, VIP, gastrin and CCK was studied. Furthermore, the possible nervous role in this effect was checked after atropine and hexamethonium treatment. Rapid wash-out significantly increased protein output (35.0 micrograms/min, in the control group without duodenal perfusion and 72.15 micrograms/min, in the perfused group) and the plasma levels of CCK (from 5.2 to 13.17 fmol/ml). Intravenous infusion of atropine significantly reduced the protein output (from 78.19 to 32.45 micrograms/min) and the plasma levels of CCK (from 10.1 to 5.55 fmol/ml), with no change in the remaining parameters in the intraduodenally perfused group. Intravenous administration of hexamethonium significantly stimulated hydroelectrolyte secretion (from 6.99 to 15.15 microliters/min) and the plasma levels of VIP (from 4.8 to 7.3 fmol/ml) and reduced the protein output (from 61.47 to 30.75 micrograms/min) and the plasma levels of CCK (from 14.56 to 6.25 fmol/ml) in the intraduodenally perfused group. Our results suggest that, in the interdigestive state, the exocrine pancreatic secretion of the rabbit is tonically inhibited. This inhibition can be divided into two different mechanisms: on the one hand there is a decrease in enzyme secretion produced by a duodenal factor and mediated by CCK and muscarinic mechanisms and on the other, there is an inhibition of hydroelectrolyte secretion with no duodenal participation which is probably controlled by nervous non-muscarinic mechanisms and VIP involvement.

Exocrine pancreatic response to intraduodenal fatty acids and fats in rabbits

1. The exocrine pancreatic secretion in rabbits after intraduodenal perfusion of, respectively, a short-chain fatty acid (propionate), a long-chain fatty acid (oleate) and a neutral fat (intralipid) has been studied. 2. Only the neutral fat and the long-chain fatty acid stimulated the hydroelectrolyte fraction of exocrine pancreatic secretion in a dose-related fashion, but this response was not mediated by secretin release. 3. Acinar secretion was more effectively stimulated after propionate perfusion than by oleate and this was governed by different mechanisms. 4. Neutral fat, without predigestion, stimulated the pancreatic enzyme secretion in the rabbit.

Nicotinic cholinergic influences in pancreatic secretion induced by intraduodenal alkaline and acid solutions in the rabbit

1. The effect of hexamethonium on the exocrine pancreatic response to intraduodenal acidification and alkalinization, and the secretin and VIP release after these stimuli, was studied. 2. The hydroelectrolyte secretion after hydrochloric acid and sodium carbonate perfusion was reduced by hexamethonium treated (322 +/- 44% of maximum response in flow rate to sodium carbonate perfusion in untreated animals vs 140 +/- 12% in pretreated animals, and 252 +/- 19% of maximum response in flow rate to HCl in untreated animals vs 166 +/- 11% in pretreated animals). 3. However, hexamethonium has no effect on secretin plasma levels after either intraduodenal acidification or alkalinization. 4. On the contrary, the ganglion blocker significantly (P < 0.01) reduced plasma VIP levels in response to intraduodenal HCl (maximum response 320 +/- 74% in untreated vs 184 +/- 44% in hexamethonium-treated animals). 5. Plasma VIP levels showed a similar increase in both untreated (maximum response: 151 +/- 12%) and ganglion blocked animals (170 +/- 26%) in response to sodium carbonate. 6. These data suggest the existence of complex neural mechanisms in the exocrine pancreatic response to intraduodenal stimuli, these mechanisms being different depending on the intraduodenal stimulus.

Dose-response effect of intraduodenal HCl on exocrine pancreatic secretion, portal secretin, and VIP plasma levels in anesthetized rats

In anaesthetized rats, a dose-dependent effect of different intraduodenal HCl loads (0.6, 1.2, 6 and 12 mmol/h) on exocrine pancreatic secretion and plasma levels of secretin and VIP has been observed. The flow rate of pancreatic juice showed a significant increase at all the doses used; the integrated percentage response (IPR) of flow were 359%, 595%, 894% and 1371% for, respectively, 0.6, 1.2, 6 and 12 mmol/h. The increase of protein output only achieved statistical significance at HCl loads of 6 mmol/h or more; the IPR of protein output were 153%, 305%, 320% and 420% for, respectively, 0.6, 1.2, 6 and 12 mmol/h HCl. Portal levels of secretin and VIP were measured by specific radioimmunoassays. Significant increase of secretin concentration was observed at HCl loads of 1.2 mmol/h or more, whilst VIP levels only increased significantly after intraduodenal HCl load of 6 mmol/h or more. The IPR of secretin release were 180%, 203%, 280% and 322% for, respectively, 0.6, 1.2, 6 and 12 mmol/h HCl and IPR of VIP release were 3%, 20%, 244% and 315% for, respectively, 0.6, 1.2, 6 and 12 mmol/h HCl. Our results suggest that secretin may play a more prominent role than VIP in stimulating exocrine pancreatic secretion in response to intraduodenal loads of acid in this species.

Spontaneous mutation for a quantitative trait in Drosophila melanogaster. II. Distribution of mutant effects on the trait and fitness

Starting from a completely homozygous population of Drosophila melanogaster, lines have been derived and subjected to 47 generations of divergent selection for abdominal bristle number (20 lines selected in each direction) or to 60-67 generations of inbreeding (100 B lines maintained by a single brother-sister mating, 100 C lines maintained by two double first cousin matings). In the selected lines, 25 were identified carrying at least 30 mutations affecting bristle number. A large fraction of these mutations (42%) were lethals. Non-lethal mutations had smaller effects on the trait, were predominantly additive and had no detectable pleiotropic effects on fitness. In the inbred lines, 21 mutations affecting bristles were individually analysed. Deleterious mutations had the largest effects on the trait (irrespective of sign) and showed recessive gene action (complete or incomplete). The rest were predominantly additive and had smaller effects. Thus, both procedures identify a quasi-neutral class of additive mutations which should be close to that responsible for standing variation in natural populations. Moreover, the results indicate a leptokurtic distribution of mutant effects, consistent with a model of natural selection acting on bristles through pleiotropic effects of pertinent loci on fitness. Consequently, neutral additive alleles of considerable effect can be found segregating at intermediate frequencies in natural populations.

Spontaneous mutation for a quantitative trait in Drosophila melanogaster. I. Response to artificial selection

Divergent selection for abdominal bristle number was carried out for 47 generations, starting from a completely homozygous population of Drosophila melanogaster. All lines were selected with the same proportion (20%) but at two different numbers of selected parents of each sex (5 or 25). A significant response to selection was obtained in 25 lines (out of 40). In most cases, it could be wholly attributed to a single mutation of relatively large effect (> 0.3 phenotypic standard deviations). A total number of 30 mutations were detected. In agreement with theory, larger responses in each direction were achieved by those lines selected at greater effective population sizes. A large fraction of mutations were lethals (10/30). Thus, the observed divergence between lines of the same effective size selected in opposite directions was smaller than expected under neutrality. The ratio of new mutational variance to environmental variance was estimated to be (0.52 +/- 0.09) x 10(-3).