4-Biphenylaldehyde and 9-anthraldehyde: two fluorescent substrates for determining P450 enzyme activities in rat and human

1. 4-Biphenylaldehyde (4-BA) and 9-anthraldehyde (9-AA) were examined as substrates for cytochrome P450 (CYPs) enzymes in rat and human. Both aldehydes were oxidized by CYPs to fluorescent carboxylic acids, which can be assayed with a high sensitivity by an easy fluorimetric method. 2. With liver microsomes from control and induced rats, the oxidation of both 9-AA and 4-BA followed simple Michaelis-Menten kinetics. Only microsomes from rats pretreated with phenobarbital (a strong inducer of P4502B1/2) could increase (about threefold) the oxidation rates (V(max)) of both aldehydes above the control values, which were 6.7+/-1.1 and 3.3+/-0.6 nmol min(-1) mg(-1) protein for 4-BA and 9-AA, respectively. On the other hand, the (K)(m)'s, which were similar for both aldehydes (about 25 micro M), did not change significantly with any inducer. The use of purified rat CYP1A1, 2E1, 2B1 and 2C11 in a reconstituted system showed that only 2B1 and 2C11 could oxidize both substrates with a high turnover. 3. In human liver microsomes, the oxidation rates of these aldehydes (1.6+/-0.2 and 0.42+/-0.1 nmol min(-1) mg(-1) protein for 4-BA and 9-AA, respectively) were lower than those of rat but with similar K(m)'s(20-26 microm). 4. The oxidation of these aldehydes was also determined with cDNA-expressed CYP1A1, 1A2, 2A6, 2B6, 2C9, 2D6, 2E1 and 3A4 and with a characterized bank of 14 human liver microsomes. In a reconstituted system, only CYP2B6, 2A6, 3A4 and with a lower turnover 2C9 oxidized both substrates. 5. Among the CYP marker activities of the 14 human samples, good correlations were only observed between CYP3A-dependent 6 beta-testosterone hydroxylase and the oxidation of 4-BA (r = 0.74) or 9-AA (r = 0.80) and between the oxidation of 4-BA versus 9-AA (r = 0.74). Weak correlations were also found between the 2B6-linked S-mephenytoin N- demethylase and the oxidation of 4-BA (r = 0.58) or 9-AA (r = 0.65). 6. Inhibition experiments revealed that the oxidation of these aldehydes was inhibited by ketoconazole, 8-methoxypsoralene and sulphophenazole, selective inhibitors for P4503A6, 2A6 and 2C9, respectively. 7. In summary, based on the use of cDNA-expressed CYPs, correlation analysis and chemical inhibition, the metabolism in human liver microsomes of these aldehydes appears primarily catalysed by CYP3A, although CYP2A6, 2B6 and 2C9 may play a role. 9-AA and particularly 4-BA, owing to the high rate of its metabolism, may be two novel useful fluorescent probe substrates for assaying CYP activities in various species.

Oxidation of N,N-dimethylformamide and N,N-diethylformamide by human liver microsomes and human recombinant P450s

N-N, dimethyl- (DMF) and N-N, diethyl-formamide (DEF) are two hepatotoxic solvents, whose metabolism has not been investigated in humans. To identify the P450 isoforms involved in the microsomal oxidation of these solvents we used (a) 12 human liver samples; (b) human recombinant P450 isoforms (1A1, 1A2, 2B6, 2C10, 2E1, 3A4); (c) chemical and immunological inhibitions. When correlation analyses were performed using enzymatic markers in human liver microsomes, the p-nitrophenol hydroxylation rate significantly correlated (r=0.87) with the dealkylation rate of DMF but not with that of DEF. Among the tested recombinant P450s only 2E1 oxidised DMF, while DEF was oxidised by 2E1, 2C10 and 3A4. 4-Methylpyrazole and anti human 2E1 IgG strongly inhibited the DMF demethylation but only partially the DEF deethylation. These findings indicate that, in the DMF metabolism, the role of 2E1 is crucial and its expression may be an important factor in determining the susceptibility of human to this solvent.

[The effects of eradication therapy in patients with chronic atrophic gastritis and seropositivity for anti-HP antibodies and histological negativity for Helicobacter pylori]

PURPOSE

The present study was undertaken to analyze both whether the elevated Helicobacter pylori levels in patients with atrophic gastritis without histologic evidence of Helicobacter pylori would be a sign of an ongoing infection and the effects of eradication on gastric atrophy.

PATIENTS AND METHODS

Twenty patients (10 M e 10 F; mean age 57.25 SD 12.19) with atrophic gastritis and elevated Helicobacter pylori titers without histological evidence for Helicobacter-like organisms were included in the study. Ten patients were randomized into eradication group (Group 1) (amoxicillin at 500 mg twice a day for 14 days, metronidazole at 500 mg twice a day for 10 days and omeprazole at 20 mg twice a day for 20 days) and 10 patients were randomized into the control group (Group 2). For all subjects, serum samples and duplicate biopsy specimens (obtained endoscopically) were collected prior the study period and approximately 6 months after the therapy or the follow-up for serum samples and 8 weeks for biopsy specimens.

RESULTS

In the Group 1, the Helicobacter pylori antibody titers dropped significantly in 73.39% of the patients (p < 0.0001), while in the Group 2, the antibody titers declined only in a patient who received antibiotics during the study period (p < 0.00006). In both groups, no significant improvement of atrophic gastritis was observed.

CONCLUSIONS

In conclusion, in patients with atrophic gastritis, the only histological evaluation of Helicobacter-like organisms colonization in gastric biopsy specimens, appeared in our study to underestimate the true prevalence of current HP infection and the importance of the bacterium in the pathogenesis and progression of such disease. Since HP infection is often associated with an increase of proliferative index, the eradication of HP could induce a mucosal protective effect against the other carcinogen factors, although it is extremely unlikely that it can promote the regeneration of a normal gastric mucosa.

Molecular Probe Data Base (MPDB)

In this paper, the current status of the Molecular Probe Data Base (http://www.biotech.ist.unige.it/interlab/ mpdb.html ) is briefly presented together with a short analysis of its activity during 1997. This has been performed by statistically evaluating the 'logs' of the Internet servers that are used for its distribution with reference to the geographical origin of the requests, the words that were utilized to carry out of the searches and the oligonucleotides that were retrieved. Planned enhancements of this database are also described. They include a revision of its data structure and, even more relevant, of its data management procedures.

Improvement of intestinal metaplasia six month after misoprostol treatment

PURPOSE

To establish whether misoprostol (a synthetic prostanoid) is effective in improving intestinal metaplasia of dyspeptic patients.

PATIENTS

Of the 206 dyspeptic patients without Helicobacter pylori, 18 (7.1%) had histological evidence of intestinal metaplasia (2 presented mild metaplasia, 9 moderate and 7 severe). They were treated with misoprostol 200 mg twice daily for six months and, after stopping the treatment, they all underwent endoscopic control.

RESULTS

There was a statistical significant improvement of intestinal metaplasia (p < 0.001) and of the activity of antral gastritis (p = 0.03). There were no significant changes in antral and body specimens during follow-up.

DISCUSSION

Though the small number of the patients and the lack of control group, our results suggest that misoprostol allows regression and/or improvement of histological IM (p < 0.001). It has proved to be effective in prevention of both gastric and duodenal ulcers induced by NSAID therapy, probably related largely to replacement of endogenous prostaglandins inhibited by the use of NSAID and it may also exerts its protective effects through inhibition of gastric acid secretion. Moreover, misoprostol showed to increase the rate of gastric blood flow, inducing a mucosal protective effect against the factors damaging gastric mucosa. It has been also documented that misoprostol regulates inflammatory cytokines and prolonged the survival of transplants, reflecting both its immunosuppressive and anti-inflammatory effect. In conclusion, since intestinal metaplasia increases the risk of gastric cancer, the use of misoprostol, in this pathology, would be of some interest.

ESWL experience in the therapy of difficult bile duct stones

In recent years, alternatives to surgery for difficult bile duct stones have been developed. Routine endoscopy fails in about 10% of patients. To verify the role of extracorporeal shock wave lithotripsy in residual CBD stones, we treated 32 patients by HM4 or MPL 9000 Dornier lithotripters. Ten (34.4%) patients needed two extracorporeal shock wave lithotripsy sessions, and 3 (10.3%) patients three. Complete clearance was achieved in 29 patients (90.6%) after one or more sessions either by endoscopic (20 pts) or percutaneous (9 pts) extraction of the debris; of the remaining 3 patients, in 2 a bilioduodenal stent was placed and in 1 electrohydraulic lithotripsy was performed. Eighteen and seven-tenths percent transient mild hemobilia, 12.5% microhematuria, and no mortality were observed. It is possible to state that in site- or size-related difficult biliary stones, extracorporeal shock wave lithotripsy is a rapid, safe, and highly effective treatment as an additional nonoperative option to resolve the failure of routine endoscopic measures.

[Echographic and ERCP-manometric study of gallbladder and Oddi's sphincter behavior in biliary colic in patients with cholelithiasis. Effects of cerulein]

In a previous study, we have shown that caerulein relieves biliary colic pain in gallstone patients. This study was initiated to determine gallbladder and sphincter of Oddi behaviour during biliary colic and their response to caerulein. In 10 gallstone patients gallbladder volume was measured by real-time ultrasonography during a biliary colic episode and 72 hours after cessation of pain, before and after caerulein administration. Basal sphincter of Oddi pressure was determined by CPRE manometry in 10 gallstone patients during biliary colic and three days after cessation of pain, before and after caerulein. The results of this study show that, during biliary colic, gallbladder volume is 8 times greater than in the post-colic state. Basal sphincter of Oddi pressure was also significantly higher during biliary colic than in the post-colic state. Caerulein relieved in all cases the biliary colic pain while reducing gallbladder volume and decreasing the sphincter of Oddi.

Effect of nizatidine versus ranitidine on gastric intraluminal prostaglandin release in duodenal ulcer patients

The role of prostaglandins in peptic ulcer disease and their relation to Helicobacter pylori infection remain controversial. This study sought to compare the effects of oral nizatidine and ranitidine on the gastric mucosal release of prostanoids in duodenal ulcer (DU) patients and to correlate prostanoid concentrations with H. pylori status. Twenty-eight patients with DUs were randomized to receive either nizatidine or ranitidine. Nizatidine 300 mg at night elevated intraluminal PGE2 concentrations; 6-keto-PGF1 alpha concentrations also rose, but did not reach statistical significance. Ranitidine induced non-significant falls in PGE2 and 6-keto-PGE1 alpha concentrations. Patients with H. pylori infection had lower PGE2 and 6-keto-PGF1 alpha concentrations than non-infected patients, but nizatidine was equally effective in increasing prostanoid levels in both groups. These findings may be considered as favourable side effects of nizatidine with uncertain clinical significance. Further studies are needed to elucidate the synergism between prostanoids, eradication of H. pylori and nizatidine in the treatment of DU.

[Rheumatic fever from 1960's to 1990's. Case records in 2 hospitals of the Lombardian area]

An epidemiological study of rheumatic fever (RF) has been done. Incidence and prevalence of RF observed in Monza Hospital from 1964 to 1990 and in Como Hospital from 1980 to 1990 both show a progressive reduction. An exception to this trend was observed in 1986 in Monza in 1985 in Como. The percentage of carditis in pediatric age is high (60-70%), often associated with arthritis and chorea. However carditis clinical picture seems nowadays less severe, probably because in the past the diagnosis was delayed. Sice 1980 no death were observed due to RF or related cardiac involvement. Relapses and residual valvulopathies are significantly reduced only when penicillin prophylaxis was correctly performed.

Single photon emission computed tomography with 99mTc HM-PAO in the study of focal epilepsy

We used 99mTc HM-PAO SPECT to study 50 patients with partial epilepsy: 47 interictally and 3 during a seizure. All 3 patients studied during a seizure presented an area of increased tracer uptake. Of those in whom recordings were taken during seizure-free intervals 35 (74%) showed perfusion asymmetries: 27 (57%) with decreased and 8 (17%) with increased uptake. We discuss the findings and compare them with those of similar studies using SPECT and positron emission tomography.

[Vasculitis in children]

Vasculitis is an inflammatory involvement with or without necrosis of blood vessels and the predominant feature of a large number of different diseases and syndromes in childhood. Vasculitis could be a primitive disease or it could participate with minor or mayor gravity to other diseases. Symptoms and prognosis vary accordingly to the size of vessels, type of inflammatory exudate and the organs involved. In pediatric age most frequent vasculitis are Schönlein-Henoch syndrome, Kawasaki syndrome and vasculitis associated with connective tissue diseases.

[Therapy of vasculitis in children]

Therapy of vasculitis syndromes varies considerably according to different forms and gravity. Mild cases often heal spontaneously. In other cases, when the causal factors are known, the removal of the offending antigen or the treatment of an underlying primary disease are sufficient to obtain remission. In the vasculitis syndromes, in which the causal factors are unknown, therapy is based on various associations of nonsteroidal antiinflammatory drugs, antiplatelet drugs, anticoagulants, corticosteroids and cytotoxic drugs, depending on the type, extention and gravity of disease. In most severe systemic necrotizing vasculitis, therapy with corticosteroids and cytotoxic drugs must be protracted for months, with inevitable side-effects, particularly severe in children. Pulse therapy with intravenous bolus of high doses of methylprednisolone seems to offer a new valid therapeutic approach, but is still under investigation. Plasmapheresis may be successful in acute and grave forms. High dose intravenous gammaglobulin therapy is indicated in the prevention of coronary involvement of Kawasaki disease. In this review these problems and therapeutic regimes suggested by different Authors are discussed, with particular attention to their application in childhood.

[Leukocytoclastic vasculitis]

Leukocytoclastic vasculitis is characterized by infiltration of polymorphonuclear leucocytes with leukocytoclastic (presence of nuclear pigments) and fibrinoid necrosis affecting the small vessels. Henoch-Schönlein purpura is characterized by non thrombocytopenic purpura, arthritis and arthralgia, abdominal pain and renal involvement. Hypocomplementemic urticarial vasculitis and cryoglobulinemia are exceptional in childhood.

[A case of stenosing ureteritis in Schoenlein-Henoch purpura]

A case of stenosing ureteritis in a 6 years old girl with Schönlein-Henoch purpura is described. In a careful review of the literature only a few cases results described. The authors discuss the problems concerning this rare and potentially serious complication of Schönlein-Henoch purpura.

[Our experience with a combination of rifampicin and minocycline in the therapy of brucellosis]

After a brief review of the literature on the treatment of brucellosis the results obtained with a new protocol (Rifampicin + Minocycline for 20 days) are reported. The combination was well-tolerated and undeniably effective producing a 94% cure rate.

[295 cases of brucellosis treated with minocycline]

295 cases of acute and subacute cases of brucellosis were treated with minocycline. It is concluded that because of its in vitro activity, its penetrability in macrophages and granulomas and its tolerance, minocycline is the antibiotic of choice for brucellosis.

[Intracranial hemorrhage caused by vitamin K deficiency in early infancy. Still a problem?]

A case of intracranial hemorrhage in a one month old infant is reported. A review of the prodromal symptoms presented by this infant seems useful to delineate a clinical picture that should allow a timely recognition of this problem in the population at risk. Furthermore, the relative frequency of this entity, due to vitamin K deficiency, in the first months of life in exclusively breast-fed infants, confirms the advisability of vitamin K supplementation at birth.

["Dense deposits" glomerulonephritis: description of a case]

The authors report a case of "dense deposits" glomerulonephritis in a girl who showed the first symptoms of asintomatic microhematuria at the age of 3 years during an ambulatorial examination which had been requested from her family doctor. After 1 year and 10 months the girl has been hospitalized and during her stay in the hospital it appeared that she still suffered of microhematuria with very low levels of serum complement. Being these results the same after the various check-ups made after her dismission from the hospital it has been decided to execute a renal biopsy, comprehending also the examination with an electronic microscopy which showed intramembranous "dense deposits" glomerulonephritis. In literature no similar cases under 4 years of age are reported.

[Plasma levels of anti-epileptic drugs. Evaluation of determinations carried out in the years 1978-1979]

The results of 701 determinations of antiepileptic drug plasma concentrations administered to 190 patients are described. It has been possible to reduce the number of prescribed drugs to 1.55 per patient, so that only 8.1% of subjects takes three or more drugs while 53% is on monotherapy. The use of the measurement of AEDs plasma concentrations resulted very useful: a) when Phenytoin (PHT) is prescribed; b) in epileptic children; c) when the patient takes two or more drugs; d) to evaluate the compliance. A significant increase (p less than 0.01) of the level/dose ratio of Phenobarbital (PB) when PHT is in, or over, the therapeutic range was observed, while at plasma concentrations of PHT below 10 micrograms/ml it does not influence the metabolism of PB.