Search PubMed⌕ Search

Biomedical subjects

A Pietrabissa

Publications and source records attributed to A Pietrabissa.

At least 37 records · Page 2Linked to original sources
PubMed2002

Sulfation of R(-)-apomorphine in the human liver and duodenum, and its inhibition by mefenamic acid, salicylic acid and quercetin.

1. The aims were to study the sulfation of R-(-)-apomorphine (hereafter apomorphine) in the human liver and duodenum, and to study the rate of inhibition of apomorphine sulphation by mefenamic acid, salicylic acid and quercetin also in the human liver and duodenum. 2. A rapid and sensitive method was developed to measure the sulfation rate of apomorphine in the human liver and duodenum. The method was based on the use of 0.4 micro M 3'-phosphoadenosine-5'-phosphosulfate-[(35)S] (PAPS) and 50 micro M apomorphine. The unreacted PAPS was precipitated with barium hydroxide, barium acetate and zinc sulfate. 3. The rate of apomorphine sulfation (mean +/- SD and median) was 261 +/- 82 and 242 pmol min(-1) mg(-1), respectively (liver), and 433 +/- 157 and 443 pmol min(-1) mg(-1), respectively (duodenum). The apomorphine sulfation rate was higher in the duodenum than in the liver (p = 0.0005). 4. Apomorphine sulfation was correlated with SULT1A1 activity in the liver (r(2) = 0.363, p = 0.005) and duodenum (r(2) = 0.494, p = 0.0005), but it did not correlate with SULT1A3 activity both in the liver and duodenum. 5. The K(m) estimate of apomorphine sulfation rate was 20 +/- 3.6 (liver) and 6.5 +/- 0.2 microM (duodenum, p = 0.024), and the V(max) estimate was 248 +/- 99 (liver) and 636 +/- 104 pmol min(-1) mg(-1) (duodenum, p = 0.018). 6. Mefenamic acid, salicylic acid and quercetin were potent inhibitors of apomorphine sulfation rate in the liver, and the IC(50) estimates were 16 +/- 0.2 nM, 54 +/- 8.6 microM and 18 +/- 2.8 nM, respectively. These compounds were poor inhibitors of apomorphine sulfation in the duodenum. 7. Apomorphine is sulfated by the human liver and duodenum, the highest activity being associated with the duodenum. The K(m) of apomorphine sulfotransferase is in the order of micro M both in the liver and duodenum. The non-steroidal anti-inflammatory drug mefenamic acid and the natural flavonoid quercetin inhibit the hepatic sulfation of apomorphine with an IC(50) in the order of nM.

Adult↗
PubMed2002

Methylation of quercetin and fisetin, flavonoids widely distributed in edible vegetables, fruits and wine, by human liver.

The aim of this investigation was to study the methylation of quercetin and fisetin, 2 chemically related flavonoids, in human liver and to this purpose, an assay was set-up to measure the rates of quercetin and fisetin methylation in human liver. The methylation rates (pmol/min/mg) of quercetin and fisetin were measured in 10 liver samples and the mean +/- SD and the median were 170+/-30 and 177 (quercetin) and 183+/-15 and 178 (fisetin). The rates of quercetin and fisetin methylation were not different (p = 0.283). The fold of variation among samples was 2 (quercetin) and 1.3 (fisetin). Methyltransferase towards quercetin and fisetin followed Michaelis-Menten kinetics, and the Km values were 2.6+/-0.3 (quercetin) and 8.6+/-0.7 microM (fisetin, p = 0.009) and the Vmax values were 187+/-20 (quercetin) and 276+/-33 pmol/min/mg (fisetin, p = 0.009). Two, 4 and 8 microl of red Chianti wine added to the incubation mixture reduced the rate of quercetin methylation to 75+/-4%, 65+/-9% and 59+/-9%, respectively, and that of fisetin methylation to 62+/-3%, 51+/-3% and 44+/-4%, respectively. In conclusion, quercetin and fisetin are methylated in human liver and their rates of methylation have a limited variation among subjects.

Adult↗
PubMed2001

Hand-assisted laparoscopic low anterior resection: initial experience with a new procedure.

BACKGROUND: Laparoscopic low anterior resection for rectal cancer has never gained wide acceptance among general surgeons, mainly due to the technical difficulties encountered during pelvic dissection. It has therefore been stated that these patients should undergo open rather than laparoscopic surgery. Hand-assisted laparoscopic surgery (HALS) is a new technique that has the potential to overcome many of the existing limitations of pure laparoscopy. In the treatment of rectal cancer, HALS could reproduce an operative setting similar to that of the open approach. METHODS: To assess the technical feasibility of hand-assisted laparoscopic low anterior resection for rectal cancer and evaluate potential benefits and drawbacks of this new procedure, a pilot study was conducted at a university hospital on 16 consecutive patients during a 12-month period. Only patients with extraperitoneal rectal cancer were included in this series. Patients' clinical data, operative time, conversion rate, complications, and early outcome measures were prospectively examined. RESULTS: There were 9 men and 7 women. The average +/- SD operation time was 238 +/- 38 min. Conversion to open surgery was never required. Ten of 16 patients were off pain medication on the third postoperative day. Eight were able to walk the day after surgery. Three minor postoperative complications were recorded. Mean postoperative stay for patients without complications was 5.6 +/- 1.4 days. CONCLUSION: From a technical standpoint, the reported hand-assisted procedure makes pelvic dissection during laparoscopic low anterior resection almost equivalent to the laparotomic operation. The incision for hand access that is needed with this technique does not seem to compromise the quick recovery of patients undergoing purely laparoscopic procedures.

Aged↗
PubMed2001

Human adult and foetal liver sulphotransferases: inhibition by mefenamic acid and salicylic acid.

1. The aim was to see whether mefenamic acid and salicylic acid had different inhibition profiles for SULT1A1 (substrate: 4-nitrophenol) and SULT1A3 (dopamine) activities and on (-)-salbutamol and minoxidil sulphation rates in the human adult and mid-gestational foetal livers. 2. The activity (pmolmin(-1) mg(-1) of SULT1A1 was 662 +/- 78 (adult) and 246 +/- 159 (foetus; p = 0.003) and that of SULT1A3 was 24 +/- 4 (adult) and 121 +/- 90 (foetus; p = 0.030). The rate (pmol min(-1) mg(-1)) of (-)-salbutamol sulphation was 109 +/- 27 (adult) and 117 +/- 34 (foetus; p = (0.144) and that of minoxidil sulphation was 202 +/- 38 (adult) and 108 +/- 44 (foetus; p = 0.001). 3. With mefenamic acid as an inhibitor, the IC50 (microM) for SULT1A1 was 0.2 +/- 0.004 (adult) and 0.01 +/- 0.002 (foetus; p = 0.001); for SULT1A3 it was 76 +/- 6 (adult) and 77 +/- 13 (foetus; p = 0.889); for the rate of ( )-salbutamol sulphation it was 0.07 +/- 0.005 (adult) and not determinable (foetus) and for minoxidil sulphation it was 1.6 +/- 0.7 (adult) and 0.15 +/- 0.04 (foetus; p = 0.076). 4. With salicylic acid as an inhibitor, the IC50 (microM) for SULT1A1 was 30 +/- 2 (adult) and 25 +/- 1 (foetus; p = 0.011); for SULT1A3 it was 690 +/- 36 (adult) and 570 +/- 16 (foetus; p = 0.229); for the rate of ( )-salbutamol sulphation it was 93 +/- 11 (adult) and 344 +/- 42 (foetus; p = 0.010); with minoxidil as substrate, the IC50 was not determinable. 5. In summary, SULT1A1, SULT1A3 and the sulphotransferases towards (-)-salbutamol and minoxidil had measurable activities in the mid-gestational human foetal liver. Mefenamic acid was a more potent inhibitor than salicylic acid of both human adult and foetal liver SULT1A1 and SULT1A3 activities. Foetal liver SULT1A1 was more susceptible than adult liver SULT1A1 to inhibition by mefenamic acid and salicylic acid. These results are consistent with the view that sulphotransferases develop early in the human foetal liver and drugs may inhibit their activities.

Adult↗
PubMed2001

Differential inhibition of human liver and duodenum sulphotransferase activities by quercetin, a flavonoid present in vegetables, fruit and wine.

1. Quercetin is a natural flavonoid present in vegetables, fruit and wine, and is known to inhibit sulphotransferase. Drugs are often taken orally and the intestinal mucosa is an early site of drug metabolism. The aims of this investigation were to study the inhibition of dopamine, (-)-salbutamol, minoxidil and paracetamol sulphation by quercetin in the duodenal mucosa and liver and to compare the IC50 in these tissues. 2. The rates (pmol min(-1) mg(-1)) of sulphation of 4-nitrophenol were 343+/-92 (liver) and 164+/-22 (duodenum; p = 0.031), of dopamine were 15+/-11 (liver) and 656+/-516 (duodenum; p = 0.049), of (-)-salbutamol 153+/-31 (liver) and 654+/-277 (duodenum; p = 0.018), of minoxidil were 156+/-47 (liver) and 105+/-7 (duodenum; n.s.), and of paracetamol were 229+/-86 (liver) and 328+/-187 (duodenum; n.s.). 3. The IC50 of quercetin for 4-nitrophenol was 48+/-11 nM (liver) and 56+/-1 nM (duodenum, n.s.), for dopamine was 5.7+/-0.7 microM (liver) and 170+/-12 microM (duodenum, p < 0.0001), for (-)-salbutamol was 54+/-4 nM (liver) and 16+/-8 microM (duodenum; p = 0.025), for minoxidil was 134+/-22 nM (liver) and 3+/-0.3 microM (duodenum, p = 0.013), and for paracetamol was 57+/-7 nM (liver) and 35+/-1 microM (duodenum; p = 0.0002). 4. Quercetin inhibited the sulphation of 4-nitrophenol, dopamine, (-)-salbutamol, minoxidil and paracetamol both in liver and duodenum. With dopamine, (-)-salbutamol, minoxidil and paracetamol as substrates, quercetin was a more potent inhibitor in the liver than the duodenum. Such a difference may reflect the different composition of sulphotransferase forms in the liver and duodenum.

Acetaminophen↗
PubMed2001

Laparoscopic and hand-assisted laparoscopic live donor nephrectomy.

Renal grafts from living donors represent an important source of organs, particularly for young patients with chronic renal failure. Laparoscopic donor nephrectomy is a relatively new technique, which has the potential to increase the pool of available kidney grafts by removing some disincentives to live donation. The technique used for left kidney donation at our center, the first to introduce laparoscopic live donor nephrectomy in Italy, is described in this report. To further reduce warm ischemia time, the kidney is preloaded inside the extraction bag and 2 staplers are used to transect the renal artery and vein. The spread of the new technique in our country and in the rest of Europe is likely to raise the issue of training in laparoscopic surgery for transplant surgeons.

Creatinine↗
PubMed2000

Thoracoscopic splanchnicectomy for pain relief in unresectable pancreatic cancer.

HYPOTHESIS: Unilateral truncal thoracoscopic splanchnicectomy (TS) provides safe and effective treatment for pain relief in patients with unresectable pancreatic cancer. DESIGN: Before-and-after trial of 24 patients undergoing 25 TS procedures. SETTING: Surgical unit at a university teaching hospital. PATIENTS: A consecutive sample of 24 patients with severe pain due to unresectable (primary or recurrent) pancreatic cancer refractory to drug therapy and with a life expectancy of less than 6 months. INTERVENTION: The key point of the reported operation is intrathoracic carbon dioxide insufflation, which allows a more distal division of the greater splanchnic nerve and a 2-port technique. MAIN OUTCOME MEASURES: Pain and the effect of this symptom on quality of life were assessed before and after TS using a 10-point visual analog pain scale (VAS) and the Nottingham Health Profile questionnaire, respectively. RESULTS: Four TS procedures were technical failures because of pleural adhesions. One patient required a contralateral procedure 12 weeks after TS. Mean (+/- SD) preoperative VAS basal score was 7.4 +/- 1.7. Twenty-four hours after TS, it was reduced to 0.6 +/- 1.0. Significant reduction of VAS scores persisted over the first 3 months after TS (P<.001). Recurrence of pain of low intensity (mean VAS basal score, 4.2) was observed in 8 patients. Significant improvement (P<.001) in each area covered by the Nottingham Health Profile questionnaire was reported at 1 month after TS. CONCLUSION: Thoracoscopic splanchnicectomy offered substantial short-term relief of pain in patients with unresectable pancreatic cancer, and significantly ameliorated the quality of their residual life.

Aged↗
PubMed2000

Differential inhibition of hepatic and duodenal sulfation of (-)-salbutamol and minoxidil by mefenamic acid.

OBJECTIVE: The aim of this investigation was to determine whether mefenamic acid and salicylic acid inhibit the sulfation of (-)-salbutamol and minoxidil in the human liver and duodenum, and if so, to ascertain whether the 50% inhibitory concentration (IC50) estimates are different in the two tissues. METHODS: Sulfotransferase activities were measured for 10 mM (-)-salbutamol and 5 mM minoxidil, and the concentration of 3'-phosphoadenosine-5'-phosphosulphate-[35S] was 0.4 microM. RESULTS: The IC50 estimates for (-)-salbutamol and minoxidil sulfation of mefenamic acid were 72 +/- 5.4 nM and 1.5 +/- 0.6 microM (liver), respectively, and 161 + 23 microM and 420 +/- 18 microM (duodenum), respectively. The figures for the liver were significantly lower (P < 0.0001) than those for the duodenum. The IC50 estimates for (-)-salbutamol sulfation of salicylic acid were 93 +/- 11 microM (liver) and 705 +/- 19 microM (duodenum, P < 0.0001). Salicylic acid was a poor inhibitor of minoxidil sulfation. CONCLUSION: The IC50 estimates for (-)-salbutamol sulfation of mefenamic acid and salicylic acid are lower than their unbound plasma concentrations after standard dosing, suggesting that mefenamic acid and salicylic acid should inhibit the hepatic sulfation of (-)-salbutamol in vivo.

Adrenergic beta-Agonists↗
PubMed2000

Mycophenolic acid glucuronidation and its inhibition by non-steroidal anti-inflammatory drugs in human liver and kidney.

OBJECTIVE: The aims of this investigation were to study the glucuronidation of mycophenolic acid (MPA) in human liver and kidney and to search for a compound that inhibits MPA glucuronidation among the non-steroidal anti-inflammatory drugs (NSAIDs). METHODS: A sensitive and reproducible radiometric assay was developed to measure the rate of MPA glucuronidation in human liver and kidney microsomes. The assay employed uridine 5'-diphosphate-[U-14C]-glucuronic acid (UDPGA) and MPA-glucuronide was isolated by TLC. The final concentrations of UDPGA and MPA necessary were 1 mM (liver), and MPA concentration was 0.5 mM (kidney). The inhibition of MPA glucuronidation was studied with 18 NSAIDs and tacrolimus. RESULTS: Glucuronosyl transferase activity followed Michaelis-Menten kinetics and the Km (mean +/- SD; mM) was 0.31+/-0.06 (liver; n = 5) and 0.28+/-0.07 (kidney; n = 5; P = 0.555); the Vmax (mean SD; nmol/mg per minute) was 5.2+/-1.4 (liver; n = 5) and 10.5+/-1.2 (kidney; n = 5; P = 0.0005). The MPA glucuronidation rates (mean +/- SD; nmol/min/mg) were 3.3+/-0.9 (liver; n = 10) and 7.8+/-1.5 (kidney; n = 10; P = 0.0002). The rate of MPA glucuronidation ranged between 2.0 and 5.1 nmol/ mg per minute with a 2.5-fold variation (liver) and between 5.7 and 9.8 nmol/mg per minute with a 1.7-fold variation (kidney). The inhibition study was performed in liver and revealed that the percentage of control ranged from 8%+/-3% (niflumic acid) to 119%+/-16% (Ketoralac). The inhibition curves for MPA glucuronidation rate were determined with the four most effective inhibitors: niflumic acid, flufenamic acid, mefenamic acid and diflunisal. Their IC50 estimates (microM) were 8+/-1, 19+/-9, 63+/-8 and 109+/-15, respectively (liver), and 8+/-2, 13+/-2, 49+/-4 and 122+/-18, respectively (kidney). The IC50 estimate for niflumic acid was eightfold lower than the peak plasma levels after a single oral dose of 250 mg of this drug. CONCLUSION: The human liver and kidney are important sites of MPA glucuronidation. MPA glucuronidation was inhibited to various extents by different NSAIDs and the four most effective inhibitors were niflumic acid, flufenamic acid, mefenamic acid and diflunisal. These drugs have similar molecular structures consisting of two aromatic rings bearing a carboxylic group.

Aged↗
PubMed2000

Inhibition of human liver phenol sulfotransferase by nonsteroidal anti-inflammatory drugs.

OBJECTIVE: The aim of this investigation was to study the inhibition of 11 nonsteroidal anti-inflammatory drugs (NSAIDs) on the human liver phenol sulfotransferases (HL-PST) and catechol sulfotransferase (HL-CST). METHODS: The activities of HL-PST and HL-CST were measured with 4 microM 4-nitrophenol and 60 microM dopamine (the sulfate acceptors) and 0.4 microM 3'-phosphoadenosine-5'-phosphosulfate [35S] (the sulfate donor). Samples of liver were obtained from five patients, aged 55-79 years, undergoing clinically indicated hepatectomy. The inhibition curves were constructed with at least five concentrations of the inhibitor. RESULTS: With the exception of piroxicam, NSAIDs inhibited HL-PST, and the estimates of the inhibitory concentration for 50% of responses (IC50; microM) were: 0.02 (mefenamic acid), 3.7 (diflunisal), 5.4 (nimesulide), 9.5 (diclofenac), 30 (salicylic acid), 41 (ketoprofen), 74 (indomethacin), 159 (ibuprofen), 245 (ketoralac) and 473 (naproxen). With 4-nitrophenol as the variable substrate, the inhibition of salicylic acid on HL-PST was non-competitive and the Ki and Kies were 18 microM and 21 microM (n = 5; P = 0.548), respectively. HL-CST was less susceptible than HL-PST to inhibition by NSAIDs, with only five drugs inhibiting this enzyme. The IC50 estimates for these drugs (microM) were 76 (mefenamic acid), 79 (diflunisal), 103 (indomethacin), 609 (salicylic acid) and 753 (diclofenac). CONCLUSION: The comparison of the IC50 estimates of HL-PST with the therapeutic plasma concentrations of NSAIDs corrected for the plasma unbound fraction was consistent with the view that mefenamic acid and salicylic acid, when administered at therapeutic doses, should impair the hepatic sulfation of those compounds that are substrates of phenol sulfotransferase.

Aged↗
PubMed2000

Glucuronidation of resveratrol, a natural product present in grape and wine, in the human liver.

1. Resveratrol, a polyphenolic compound present in grape and wine, has beneficial effects against cancer and protective effects on the cardiovascular system. It has been shown that the compound is sulphated in human liver and the aims of the present investigation were to study resveratrol glucuronidation in human liver microsomes and to determine whether flavonoids inhibit resveratrol glucuronidation. 2. A simple and reproducible radiometric assay for resveratrol glucuronidation was developed. The assay employed uridine-5'-diphosphoglucuronic acid-[14C] and unlabelled resveratrol. Resveratrol-glucuronide was isolated by TLC. The intra- and interassays variabilities were 1 and 1.5%, respectively. 3. The rate of resveratrol glucuronidation was measured in 10 liver samples. The mean +/- SD and median of resveratrol glucuronidation rate were 0.69 +/- 0.34 and 0.80 nmol/min/mg, respectively. Resveratrol glucuronosyl transferase followed Michaelis-Menten kinetics and the Km and Vmax (mean +/- SD; n = 5) were 0.15 +/- 0.09 mM and 1.3 +/- 0.3 nmol/min/mg, respectively. The intrinsic clearance was 11 +/- 4 x 10(-3) ml/min.mg. 4. The flavonoid quercetin inhibited resveratrol glucuronidation and its IC50 (mean +/- SD; n = 3) was 10 +/- 1 microM. Myricetin, catechin, kaempferol, fisetin and apigenin (all at 20 microM) inhibited resveratrol glucuronidation and the percent of control ranged between 46% (catechin) to 72% (apigenin). 5. The present results show that resveratrol is glucuronated in the human liver. Glucuronidation may reduce the bioavailability of this compound however, flavonoids inhibit resveratrol glucuronidation and such an inhibition might improve the bioavailability of resveratrol.

Adult↗
PubMed2000

Fenamates and the potent inhibition of human liver phenol sulphotransferase.

1. The inhibition of the human liver phenol sulphotransferase (HL-PST) and catechol sulphotransferase (HL-CST) by five fenamates has been studied and the activities of HL-PST and HL-CST were measured with 4-nitrophenol and dopamine as substrates, respectively. 2. The IC50 for inhibition of HL-PST were 0.02 microM (mefenamic acid); 0.12 microM (tolfenamic acid); 0.28 microM (niflumic acid); 0.87 microM (meclofenamic acid) and 1.50 microM (flufenamic acid). 3. HL-CST was less susceptible than HL-PST to the inhibition by fenamates and the IC50 for HL-CST were 36 microM (tolfenamic acid); 70 microM (flufenamic acid); 76 microM (mefenamic acid); 180 microM (niflumic acid) and 185 microM (meclofenamic acid). 4. The ratios of the IC50 for HL-CST:HL-PST were drug-dependent and ranged from 47 (flufenamic acid) to 3800 (mefenamic acid). Mefenamic acid is a relatively potent and selective inhibitor of HL-PST. 5. The IC50 for HL-PST obtained with mefenamic acid was three orders of magnitude lower than the peak plasma concentration of this drug after an oral dose of 0.5 g. Accordingly, mefenamic acid should impair sulphation in vivo.

Arylsulfotransferase↗
PubMed2000

Sulphation of resveratrol, a natural product present in grapes and wine, in the human liver and duodenum.

1. Resveratrol, a polyphenolic compound present in grapes and wine, has beneficial effects against cancer and protective effects on the cardiovascular system. It is present in the diet, and the hepatic and duodenal sulphation might limit the bioavailability of this compound. The aim was to study the sulphation of resveratrol in the human liver and duodenum. 2. A simple and reproducible radiometric assay for resveratrol sulphation was developed. It employed 3'-phosphoadenosine-5'-phosphosulphate-[35S] as the sulphate donor and the rates of resveratrol sulphation (mean +/- SD, pmol/min/mg cytosolic protein) were 90 +/- 21 (liver, n = 10) and 74 +/- 60 (duodenum, n = 10, p = 0.082). 3. Resveratrol sulphotransferase followed Michaelis-Menten kinetics and Km (mean +/- SD; microM) was 0.63 +/- 0.03 (liver, n = 5) and 0.50 +/- 0.26 (duodenum, n = 5, p = 0.39) and Vmax (mean +/- SD, pmol/min/mg cytosolic protein) were 125 +/- 31 (liver, n = 5) and 129 +/- 85 (duodenum, n = 5, p = 0.62). 4. Resveratrol sulphation was inhibited by the flavonoid quercetin, by mefenamic acid and salicylic acid, two commonly used non-steroidal anti-inflammatory drugs. IC50 of resveratrol sulphation for quercetin was 12 +/- 2 pM (liver) and 15 +/- 2 pM (duodenum), those for mefenamic acid were 24 +/- 3 nM (liver) and 11 +/- 0.6 nM (duodenum), and those for salicylic acid were 53 +/- 9 microM (liver) and 66 +/- 4 microM (duodenum). 5. The potent inhibition of resveratrol sulphation by quercetin, a flavonoid present in wine, fruits and vegetables, suggests that compounds present in the diet may inhibit the sulphation of resveratrol, thus improving its bioavailability.

Adult↗
PubMed2000

Sulphation of resveratrol, a natural compound present in wine, and its inhibition by natural flavonoids.

1. Resveratrol, a polyphenolic compound present in grape and wine, has beneficial effects against cancer and protective effects on the cardiovascular system. Resveratrol is sulphated, and the hepatic and duodenal sulphation might limit the bioavailability of this compound. The aim of this study was to see whether natural flavonoids present in wine, fruits and vegetables inhibit the sulphation of resveratrol in the human liver and duodenum. 2. In the liver, IC50 for the inhibition of resveratrol sulphation was 12+/-2 pM (quercetin), 1.0+/-0.04 microM (fisetin), 1.4+/-0.1 microM (myricetin), 2.2+/-0.1 microM (kaempferol) and 2.8+/-0.2 microM (apigenin). Similarly, in the duodenum, IC50 was 15+/-2 pM (quercetin), 1.3+/-0.1 microM (apigenin), 1.3+/-0.5 microM (fisetin), 2.3+/-0.1 microM (kaempferol) and 2.5+/-0.3 microM (myricetin). 3. The type of inhibition of quercetin on resveratrol sulphation was studied in three liver samples and was determined to be non-competitive and mixed in nature. Km (mean+/-SD; microM) was 0.23+/-0.07 (control), 0.40+/-0.08 (5 pM quercetin) and 0.56+/-0.09 (10 pM quercetin). Vmax (mean+/-SD; pmol min(-1) x mg(-1)) was 99+/-11 (control), 73+/-15 (5 pM quercetin) and 57 +/- 10 (10 pM quercetin). Kj and Kies estimates (mean+/-SD) were 3.7+/-1.8 pM and 12.1+/-1.7 pM respectively (p = 0.010). 4. Chrysin was a substrate for the sulphotransferase(s) and an assay was developed for measuring the chrysin sulphation rate in human liver. The enzyme followed Michaelis-Menten kinetics and Km and Vmax (mean+/-SD) measured in four livers were 0.29+/-0.07 microM and 43.1+/-1.9 pmol x min(-1) x mg(-1) respectively. 5. Catechin was neither an inhibitor of resveratrol sulphation nor a substrate of sulphotransferase. 6. These results are consistent with the view that many, but not all, flavonoids inhibit the hepatic and duodenal sulphation of resveratrol, and such inhibition might improve the bioavailability of this compound.

Aged↗
PubMed1999

Development and in vitro testing of a miniature robotic system for computer-assisted colonoscopy.

In this article we present a new concept for computer-assisted colonoscopy based on a miniature robot capable of propelling itself semiautonomously along the colon. The miniature robot is designed to perform the same functions as current colonoscopy systems-i.e., visualization and tissue sampling for biopsy-and exploits an innovative inchworm-like locomotion principle based on adhering to the colon wall by vacuum suction. The miniature robot is connected by a thin and flexible umbilical cable to an external control unit; this unit provides pneumatic actuation signals in the appropriate sequence to the miniature robot, and information on the robot's functioning to the endoscopist, who can either teleoperate or directly supervise its operation. A prototype colonoscopy system using this robot has been fabricated and tested in vitro, with promising results. The proposed concept has strong potential for further development, since miniaturization and functional integration of instrumentation and tools, together with computer assistance, not only make colonoscopy more acceptable, but can also open up a wide range of new applications in endoluminal diagnosis, therapy, and surgery.

Animals↗
PubMed1999

Laparoscopy and laparoscopic ultrasonography for staging pancreatic cancer: critical appraisal.

A pilot study was designed to elucidate the role of staging laparoscopy for determining resectability in patients with pancreatic cancer. The additional value of laparoscopic contact ultrasonography (LCU) was also evaluated with specific regard to its ability to detect hepatic metastases and assess vascular infiltration of the portomesenteric trunk. A consecutive sample of 50 patients referred for operation of a suspected pancreatic cancer were submitted to preoperative contrast-enhanced high-resolution computed tomography (CT) and staging laparoscopy combined with LCU at a university hospital. For those progressing to exploratory laparotomy, the intraoperative findings relating to tumor diffusion and vascular infiltration were compared to CT, laparoscopic, and LCU data. Analytical description of the laparoscopic findings is given. Row data of predicted versus observed vascular infiltration were tabulated for CT and LCU. The sensitivity, specificity, and overall accuracy of each diagnostic test were calculated for comparative analysis. Laparoscopy alone prevented unnecessary laparotomy in 20% of cases. A complete procedure could not be achieved in 28% of patients. Three false-negative staging results occurred. LCU identified small (benign) hepatic nodules not seen by CT in 8% of patients. Sensitivity, specificity, and overall accuracy for assessing vascular infiltration were 82%, 53%, and 69% for CT and 94%, 80%, and 87% for LCU. Laparoscopy was confirmed to be safe and effective for staging pancreatic cancer. Because of its unique capabilities to detect even small peritoneal tumor deposits a quick exploration immediately before laparotomy is advised in all patients. The additional benefit of a more extensive procedure is not supported by our results. Although LCU appears to define the vascular involvement more accurately than conventional CT, the limitation of getting clinically useful ultrasound data in all the patients suggests its adoption in only a selected population.

Adult↗
PubMed1999

Safety of adrenal vein ligation during endoscopic adrenalectomy: a technical note.

Endoscopic adrenalectomy has been recommended for the treatment of several benign adrenal diseases. The safety of this procedure largely depends on a careful surgical dissection and appropriate hemostatic technique. An established slipknotting technique was employed to control the main adrenal vein in a consecutive series of 14 patients undergoing endoscopic adrenalectomy. The operative steps to ligate the adrenal pedicle are described. A Medline search also was conducted to identify all reported bleeding episodes associated with this procedure. All attempted ligatures of the main adrenal vein were completed successfully by the described technique, and none of our patients required perioperative blood transfusion. Twenty-eight episodes of bleeding collected from the literature were analyzed. Hemorrhagic accidents related to dislodgement of clips were documented at least in three patients. The cause of bleeding was unspecified in 10 patients. Extracorporeal ligation of the main adrenal vein is feasible, safe, and advisable to prevent the occurrence of hemorrhage during endoscopic adrenalectomy.

Adrenal Glands↗