Přemysl Frič

Lactic dehydrogenase isoenzymes in the aortic wall

Summary LDH isoenzymes were investigated by the method of electrophoresis in agar-gel and tetrazolium detection (INT or nitro-BT were used) in supernatants of the homo-genates of aortae (intima-media samples) of the followingspecies: rat, rabbit, guinea-pig, pig, cock, duck, and man. In the aortic wall of the investigated species we found marked differences in the distribution pattern of LDH isoenzymes which did not correspond to their behaviour in other organs. The relative values of the faster migrating portions in the adventitia of the human aorta were higher than in the intima or media. Ln plaques slower migrating parts were increased in comparison with the unaffected intima. A shift towards the slow migrating portions was observed with increasing in age. The pattern of LDH isoenzymes in the aortic muscle cells is rather specific and can be hardly compared with that of smooth muscles in other organs. Hormonal control of LDH isoenzymes in rat aortae is suggested from the increase of slower migrating parts in castrated and particularly in hypothyreoid animals. An opposite effect was observed after thyreoidine administration. The implications of these fmdings are discussed. The determination of isoenzymes represents a new approach to studies of the metabolism of the vascular wall. Their changes may become apparent before the ‘total’ activity of the respective en-zyme is affected.

Effective peritoneal therapy of acute pancreatitis in the rat with glutaryl-trialanin-ethylamide: a novel inhibitor of pancreatic elastase.

The six hour peritoneal lavage with glutaryl-trialanin-ethylamide, a low molecular competitive inhibitor of pancreatic elastase (IC50-8 mumol/l), effectively suppresses the evolution of taurocholate induced acute pancreatitis in the rat. The lavage alone is followed by a marked decrease of fat necrosis and amylase and lipase activity in serum. The area of pancreatic haemorrhage was significantly reduced only after the lavage solution was supplemented with Glt-Ala3-NHEt. The effect was not enhanced by a bolus injection of the inhibitor before starting the lavage. The combination of Glt-Ala3-NHEt with aprotinin or nafamstate mesilate produced only marginal greater benefit. The effect of Glt-Ala3-NHEt on pancreatic haemorrhage is time and dose related even with delayed onset of the lavage. Animals treated with peritoneal lavage without Get-Ala3-NHEt lived longer than controls (p less than 0.05), but by 60 hours the survival rate of both groups was almost the same (76 v 74%). All animals lavaged with Glt-Ala3-NHEt survived 120 hours and the difference in the survival rate between this and both remaining groups was significant (100% v 76% v 74% - p less than 0.05). The results were considered favourable and preliminary clinical trials of Glt-Ala3-NHEt in subjects with acute pancreatitis justified.

ENZYMES OF THE JEJUNAL ENTEROCHROMAFFINE CELLS IN MAN.

SummaryA study of enzymatic equipment of enterochromaffine cells (e.c.) in jenual biopsies obtained with a Crosby capsule in normal humans and patients with nontropical sprue was undertaken. The following enzymes were demonstrated: alkaline phosphatase and adenosine triphosphatase (cell membrane), acid phosphatase (corpuscular), non-specific esterase (diffuse and corpuscular, predominantly eserine resistant, in corpuscular localization E 600 resistant), DPN- and TPN-diaphorases and dehydrogenases of lactic acid, malic acid, isocitric acid, glucoso-6-phosphoric acid, succinic acid, β-hydroxybutyric acid and α-glycerophosphoric acid. Enzyme activities were not equal in all cells suggesting some type of secretory cycle. In most patients with untreated nontropical sprue or with the disease in relapse e.c. were more numerous and hypertrophic with elevated activities of non-specific esterase and acid phosphatase. Implications of these results are briefly discussed.

Monoclonal antibodies reacting with gliadin as tools for assessing antigenic structure responsible for exacerbation of celiac disease

Monoclonal antibodies reactive with gliadin were prepared by fusion of spleen cells isolated from gliadin-immunized BALB/c mice with myeloma cells. The reactivity of mAbs with different preparations of gliadin and their enzymatic digest were measured using ELISA method. The mAb produced by GL 1 clone was shown to react preferentially with alpha-gliadin and its enzymatic digest.

Isolation and analysis of peptidic fragments of α-gliadin using reversed-phase high-performance liquid chromatography

Summary Peptidic fragments of α-gliadin were obtained by peptic-tryptic-pancreatic (PTP) digestion of the α-gliadin fraction isolated by ion-exchange chromatography on a sulphopropyl-Sephadex C-50 column. The proteolytic digest was fractionated by ultrafiltration into three subfractions, PTPa 1 –PTPa 3 . The subfraction PTPa 2 was then analysed and individual peaks were separated using reversed-phase high-performance liquid chromatography (RP-HPLC) using a gradient of acetonitrile in 0.1% trifluoroacetic acid and a Separon SGX-C 18 sorbent. A 100-mg amount of the PTPa 2 subfraction was separated in a single analysis by preparative RP-HPLC and twenty peaks were obtained for further characterization. The molecular mass in range 300–3000 was established for individual peptidic fragments by gel-permeation chromatography on a TSK-G2000 SW column.

Early detection of sporadic pancreatic cancer: time for change

Sporadic pancreatic cancer amounts to ∼90% of all pancreatic cancers. It is a gloomy depressive disease and the most recalcitrant malignancy, with a very low 5-year survival (3–6%). At present, diagnostic methods are commonly applied, as used half a century ago, after the appearance of local and systemic symptoms (abdominal and back pain, cholestasis, painless jaundice, fatigue, anorexia, weight loss, anemia, peripheral phlebitis, and cachexia). Unfortunately, these symptoms are harbingers of an advanced disease. The subsequent imaging methods may offer additional information on the location, size, and morphology of the lesion, but they do not influence the prognosis. Radical surgery may be offered to 15–20% of patients. The relapses after surgery are frequent and chemotherapy may be palliative. Preventive programs represent the only possibility of improvement. We propose the first multistep and multidisciplinary preventive program for early detection of sporadic pancreatic cancer for the differential identification of average-risk patients who probably have the disease from those who do not.

Serum microRNA-196 and microRNA-200 in pancreatic ductal adenocarcinoma of patients with diabetes mellitus.

BACKGROUND/OBJECTIVES Our aim was to compare expressions of 6 microRNAs (miRNAs) in patients with pancreatic ductal adenocarcinoma (PAC) and non-cancer patients, moreover according to the presence or absence of diabetes mellitus. METHODS Expressions of miRNA-192, -196, -200, -21, -30 and -423 were measured in 77 patients with PAC and 64 non-cancer patients (34 patients with type 2 DM and 30 control persons). 60 patients with PAC (78%) had DM or prediabetes and it was of new-onset (less than 2 years before the cancer diagnosis) in 44 out of them. RESULTS The expressions of all microRNAs were 1.4-3.7 times higher (significantly) in the PAC group compared to non-cancer patients. No difference was found between PAC diabetic and PAC non-diabetic patients. MicroRNA-200 was significantly higher in PAC patients with significant body weight loss against those without weight loss. Adding miRNA-196 and -200 to the current marker CA 19-9 improved the discriminative ability of the test (compared to CA 19-9 alone). CONCLUSION MicroRNA-196 and -200 could be used as additional markers in PAC diagnosis.

Early pancreatic carcinogenesis - risk factors, early symptoms, and the impact of antidiabetic drugs.

Risk factors (long-term diabetes, obesity) and early symptoms (new-onset diabetes, loss of weight, or persistent low body mass) are the initial symptoms of pancreatic carcinogenesis. They may be influenced by antidiabetic drugs and their correct evaluation is a prerequisite for early diagnosis of pancreatic cancer (PC). We review the risk factors, early symptoms, and the impact of antidiabetic drugs on early pancreatic carcinogenesis. The main source of data was the database Medline/PubMed and abstracts of international congresses (DDW, UEGW). The risk factors and early symptoms are integral components of the familial PC surveillance and sporadic PC screening. Preventive programs should always be include multistep and multidisciplinary procedures. The correct evaluation of antidiabetic drugs and their interactions with other components of pancreatic carcinogenesis may influence the early diagnosis of PC.

The significance of the n-acyl residue of L-alanyl-L-alanyl-L-alanine p-nitroanilide for cleavage by pancreatic elastase

Pancreatic elastase (EC 3.4.4.7) has been lately the subject of increased interest for several reasons. It is of importance in the pathogenesis of acute pancreatitis, especially in damage to the blood vessels [ 1 ] . It is not inhibited by clinically used protease inhibitors of the Kunitz type [2]. New specific substrates of various types for the estimation of elastolytic activity have been synthesized [3-51. We have directed attention to chromogenic substrates, i.e. p-nitroanilides of N-acylated tripeptide L-alanyl-L-alanyl-Lalanine. So far N-acetyl[6] and N-tert-butyloxycarbonyl-tripeptideg-nitroanihde [7] have been used for this purpose. We have investigated the significance of the hydrophilic acyl residue of the N-terminal amino group (Ala),-NAP* for the solubility, rate of enzymic hydrolysis and specificity for pancreatic elastase. For this purpose residues of dicarboxylic acids have been used: maleic acid (Mal), succinic acid (Sue) and glutaric acid (Glt) and the substrates prepared compared with the previously described Ac(Ma),-NAP PI.

Precursors of pancreatic cancer.

Pancreatic cancer (PC) behaves very differently in comparison with other malignancies. Its incidence has been increasing continuously; mortality has not decreased, the diagnosis is frequently late, radical surgery is performed only in 15–20% of patients, and chemotherapy is only palliative. PC occurs in three different forms. Sporadic PC accounts for 90% of all PCs. Its most frequent form is the pancreatic ductal adenocarcinoma. The remaining 10% constitute two minority groups: familial PC (7%) and PC as a manifestation of a genetic cancer syndrome (3%). PCs are preceded by a precancerous lesion (precursor). At present, six different precursors are known. They have different histomorphological characteristics and malignant potential. The recognition and correct interpretation of individual precursors influences adequate clinical decision-making. The publication surveys the present knowledge of individual precursors and their role in the early pancreatic carcinogenesis.