Displacement chromatography on cyclodextrin-silicas. I. Separation of positional and geometrical isomers in the reversed-phase mode

The retention behaviour of several charged and uncharged solutes on beta-cyclodextrin-silica was studied as a function of the methanol concentration, ionic strength and pH of the eluent in order to develop efficient displacement chromatographic separations for positional and geometric isomers. These retention curves were used to predict the eluent (carrier solvent) compositions that result in solute retentions in excess of k' = 10. The adsorption isotherms of several cationic detergents were determined in these carrier solutions and were found to be convex. The adsorption isotherms of several positional isomers used as test solutes were also determined in these carrier solutions. The adsorption isotherms permitted the development of efficient displacement chromatographic separations for the isomers tested. Column loadings as high as 58 mg were achieved on a regular 4.6 mm I.D. analytical-scale cyclodextrin silica columns.

Displacement chromatography on cyclodextrin-silicas. II. Separation of cis-trans isomers in the reversed-phase mode on alpha-cyclodextrin-silica

The feasibility of preparative separations of cis-trans isomers by displacement chromatography on analytical-scale alpha-cyclodextrin-silica columns operated in the reversed-phase mode is demonstrated by using the isomers of 3-hexen-1-ol as model substrates and n-alkanols as displacers. The importance of matching the size of the cyclodextrin cavity and the solutes is shown. The crucial role of the displacer (both type and concentration) in the success of the displacement chromatographic separation is demonstrated.

[Thoughts on the causes of seasonality of menarche]

The pineal gland plays an important role in the production of melatonin and in the synchronization of the reproduction process in seasonal breeding animals. Changes in the duration of day length are the most important stimulatory factors. In humans the pineal gland may not only have a physiological role in the seasonality of maturation, but also concerning the simultaneously observable changes of serum hormone and serum melatonin levels as well as in regard of changes in hair colour in prepuberal children. Therefore the pineal gland seems to play an important physiological role in the timing of human maturation.

The effect of the platelet-activating factor antagonist, BN 52021, on human natural killer cell-mediated cytotoxicity

The influence of the platelet-activating factor (PAF) antagonist, BN 52021, on human natural killer (NK) cell cytotoxicity against K 562 target cells was determined. Cytotoxicity was measured by a short-term (4 hr) 51Cr-release assay. The cytotoxicity was significantly reduced in the presence of PAF antagonist at concentrations from 30 to 120 microM. This reduction of killing was not due to the impairment of binding of effector cells to target cells. Pretreatment of K 562 target cells with the PAF antagonist led to a greater inhibition of NK cell cytotoxicity compared with that observed when the effector cells were preincubated with BN 52021. Thus, the inhibition of cytotoxicity appears to be due to an effect of BN 52021 on target cells rather than on lymphocytes. Furthermore, the increase in NK activity induced by interferon was less pronounced when BN 52021 was added in the incubation medium. The natural cytotoxicity of platelet-depleted or large granular lymphocyte-enriched effector cell populations was inhibited by the PAF antagonist in a similar manner. The effect of BN 52021 appears to be related to its specific PAF antagonistic activity since a similar action on NK cells was noted with two other structurally unrelated PAF antagonists, BN 52111 and WEB 2086. In contrast, Ginkgolide J (BN 52024), which is structurally related to BN 52021 but lacks PAF antagonistic activity, was ineffective in inhibiting NK cell cytotoxicity. Finally, synthetic PAF induces a dose-dependent cytotoxic action on K 562 cells and this effect of the autacoid is inhibited by BN 52021. These observations provide indirect evidence that PAF could play a role in the mechanism(s) of NK cytotoxity.

Two components of type III protein kinase C with different substrate specificities and a phospholipid-dependent but Ca2+-inhibited protein kinase in rat brain

The activities of rat brain protein kinase C isoenzymic fractions separated by hydroxyapatite chromatography were measured with histone H1 or the oligopeptide Ala-Ala-Ala-Ser-Phe-Lys-Ala-Lys-Lys-amide as substrates. The oligopeptide was a better substrate than histone H1 for nearly all of the protein kinase C fractions. Two subfractions of type III isoenzyme were resolved (IIIa and IIIb); type IIIb was characterized by a very low histone kinase activity compared to its peptide kinase activity. In some brain extracts a phospholipid-dependent but Ca2+-inhibited protein kinase was also observed which was eluted from the hydroxyapatite column between type II and III isoenzymes of protein kinase C.

Isoenzyme patterns of protein kinase C and a phospholipid-dependent but Ca2+-inhibited enzyme fraction in the crude extracts of different tissues

We compared the protein kinase C isoenzyme patterns of crude extracts of rabbit brain, cerebellum, spleen, thymus and human and pig granulocytes. The isoenzymes were fractionated by hydroxyapatite chromatography and the protein kinase C activity was determined with a synthetic oligopeptide substrate. In the extracts of several tissues we also observed an enzyme fraction which was activated by phosphatidylserine + diacylglycerol but inhibited by Ca2+.

Effect of the platelet-activating factor antagonist BN 52021 on human natural killer cell cytotoxicity

The possible role of platelet-activating factor (PAF) in natural killer (NK) cell cytotoxicity was investigated by examining the effect of the PAF antagonist BN 52021 in NK cytotoxicity towards 51Cr-labelled K 562 target cells. When BN 52021 (30-120 microM) was added during the assay, a dose-dependent inhibition of NK activity was observed. The inhibition of cytotoxicity by BN 52021 was not due to an alteration of the binding of lymphocytes to K 562 cells. When lymphocytes were preincubated with BN 52021 (60 microM) for 60 min before the target cells were added, the inhibitory effect of the drug was similar to that observed when it was added at the start of the reaction. Inhibition was more pronounced when the target cells were pretreated for 60 min before the start of the assay. BN 52021 (60 microM) also inhibited gamma interferon induced NK activity. These studies provide indirect evidence that NK cells can generate PAF and that this mediator is involved in cytotoxic processes.

Endocrine pancreas in chronic pancreatitis. A qualitative and quantitative study

This study includes nine patients with diabetes mellitus (DM) and chronic pancreatitis (CP) (group I); 11 patients without DM and with CP (group II); and a control group (group III) consisting of five autopsy cases with neither DM nor CP. These groups were evaluated by routine histologic stains and immunocytochemical stains for insulin, glucagon, and somatostatin. Semiquantitative assessment of the degree of exocrine pancreatic atrophy and of two endocrine features (diffuse endocrine proliferation and ductoendocrine proliferation) was performed for each pancreas. Quantitative determination of the cell composition was carried out in three kinds of islets (parenchymal, sclerosis, and newly formed). The mean percentages of the insulin-producing B cells were significantly lower in the parenchymal (44.5%) and new (34.3%) islets of diabetic patients than in the controls (67.8%) and parenchymal (59.4%) islets of nondiabetic patients. The mean percentages of glucagon-producing A cells revealed significant increases in the parenchymal (43.0%) and new (55.7%) islets of diabetic patients as compared with the controls (24.3%) and parenchymal (32.2%) islets of nondiabetic patients. The mean percentage of somatostatin-producing D cells was significantly increased in the parenchymal islets (12.4%) of diabetic patients as compared with the parenchymal islets (8.2%) of nondiabetic patients and controls (7.5%). These findings correlate with clinical data of frequent DM in CP, but are partly in contrast with previous immunohistochemical analysis findings in CP.

A case of primary sclerosing cholangitis mimicking chronic pancreatitis

A case of a 37 year old male is presented, who died from primary sclerosing cholangitis (PSC) with characteristic radiological picture and laboratory data suggesting chronic pancreatitis (CP).

[Results of surgical treatment of Dupuytren's contracture]

Ninety-five Patients with Dupuytren's contracture, treated by partial (subtotal) aponeurectomy, have been evaluated retrospectively from various points of view. The immediate postoperative status and the results one to five years later were compared. The authors establish that Dupuytren's contracture can be treated with very favourable effect, but the good results deteriorate later due to recurrence. This deterioration remains temporarily unchanged in the second and third years, but the worsening continues till the end of the fifth year. The functional state shortly after the operation was 41% better than the preoperative one, becoming 18% worse after the fifth year, but even then was 22.6% better than the preoperative condition.

Proteolytic activation of protein kinase C in the extracts of cells treated for a short time with phorbol ester

A 10 min treatment of human neutrophils with phorbol 12-myristate 13-acetate (PMA) has been reported to induce accumulation of the proteolytically activated Ca2+/phospholipid-independent catalytic fragment of protein kinase C in the cytosol of intact cells [(1986) J. Biol. Chem. 261, 4101-4105]. We investigated the proteolytic conversion of protein kinase C to Ca2+/phospholipid-independent form in the cytosol and membrane fractions of pig neutrophils. The activity of protein kinase C was measured with its specific oligopeptide substrate Ala-Ala-Ala-Ser-Phe-Lys-Ala-Lys-Lys-amide designed previously. In our experiments the short-term treatment of neutrophils with PMA did not induce the accumulation of the proteolytically activated form of protein kinase C in the cytosol of intact cells. However, treatment of cells with PMA enhanced the limited proteolysis of protein kinase C during the preparation of cell extracts.

Determination of euthyroid thyroid mass

Proposals have been made for modification of different formulas used to determine the thyroid weight, by which the 'most probable' value of the normal thyroid mass can be determined. With the help of this method, thyroid masses of euthyroid individuals located in Budapest and its surroundings were determined using a combined scintigraphic and ultrasound method. As an average of 103 cases, the 'most probable' value of normal thyroid mass of the population is 20.9 g (range 15.1-38.8 g).

Simple and reliable conditions for routine, long-term culturing of fetal human pancreatic tissue fragments

Fetal human pancreatic tissue fragments were isolated and cultured for 18 wk. Insulin production was almost continuous during this period. Multiplication of cells was observed at the second week, and these cells later aggregated as epithelioid cells and formed pseudoislets. The growth characteristics, insulin-like immunoreactivity, and endocrine properties of these cells were evidenced by light microscopy, immunocytochemistry, electron microscopic examination, and measurement of the total insulin content. These results indicate that long-term culture of fetal islets may be useful in clinical work and provides a possible method for increasing islet mass and reducing immunogenicity.

Cyclic AMP-dependent protein kinase stimulates the phosphorylation of phosphatidylinositol to phosphatidylinositol-4-monophosphate in a plasma membrane preparation from pig granulocytes

Plasma membranes prepared from pig granulocytes were incubated in the presence of [gamma-32P]ATP. The dissociated catalytic subunit of cyclic AMP-dependent protein kinase stimulated the incorporation of 32P into both the protein and lipid fractions of the membrane. The SDS gel-electrophoretic analysis of the 32P-labelled proteins showed that the protein kinase phosphorylated preferentially a 24000-Mr protein, though other 32P-labelled proteins were also detected. 32P-labelled membrane lipids were analysed in two different thin layer chromatographic systems. 32P-labelling was found exclusively in polyphosphoinositides. On addition of the protein kinase the 32P-labelling of both polyphosphoinositides was increased but a higher amount of phosphate was incorporated into phosphatidylinositol-4-phosphate than into phosphatidylinositol-4,5-bisphosphate.

[Bone age of children in 2 communities in Hungary with different fluoride levels in the drinking water]

The adverse effects of ingested fluoride were investigated. The bone-age of children consuming drinking water containing optimum (about 1 mg/l) fluoride concentration with regard to caries prophylaxis was compared with the bone-age of those consuming drinking water containing low (0.14-0.26 mg/l) fluoride concentration. The examinations were conducted on 7-14-year old Hungarian children. The bone-age was determined by the TW2 method. No significant difference was found between the bone-age of the children belonging to the group consuming water with optimum fluoride concentration and those in the other group consuming water with low fluoride concentration.

Studies on the growth and survival of Staphylococcus aureus in corned beef

The growth of an enterotoxin A producing strain of Staphylococcus aureus in corned beef was investigated. In the inoculated 6 lb. canned product the bacteria spread throughout the meat and attained high numbers. The rate of spread of the organisms was related to the temperature and length of storage of the cans and the numbers of bacteria inoculated. Cans which had been stored for more than four months showed high counts of the bacteria throughout the meat. It was noted that with the long term contaminated product counts of S. aureus on some selective media may give falsely low results. Numbers of S. aureus on meat inoculated by handling after removal from the can were initially extremely variable. More uniform distribution and higher counts were attained only if the meat was exposed for some hours at ambient temperature or above. The significance of the results to the investigation of outbreaks of food poisoning suspected of being associated with canned corned beef is discussed.