Longitudinal changes of brain amino acid content occurring before, during and after epileptic activity.

In cats affected with cortical epileptogenic foci induced by penicillin application to and cobalt implantation into the pericruciate area, the brain amino acids contents were determined in the focus as well as in extrafocal areas. In different groups of animals, brain removal for biochemical determinations was performed at different times before, during and after epilepsy and the values compared to controls. The only amino acid to show a significant change before appearance of spikes in both types of epilepsy was taurine, which decreased. Cobalt epilepsy was accompanied by changes in a larger number of amino acids than penicillin epilepsy: in the former the brain content of taurine, GABA, aspartate, glutamate, serine, threonine, glycine and alanine was altered. The changes were proportional to the severity of epilepsy and more prominent in the focus area. After disappearance of spikes the levels of most amino acids returned to normal except for some amino acids, previously unaffected by penicillin epilepsy, which were decreased. It is proposed that the decrease in brain taurine, occurring before the appearance of penicillin and cobalt epilepsy, could increase the excitability of a certain neuronal population and thus, by potentiating the effects on neurons of penicillin and cobalt, contribute to the initiation of epilepsy.

Quality assurance for steroid receptor assay in human breast cancer: six years experience of the Italian Committee.

Since 1979 the quality control design proposed by the Italian ad hoc Committee has evaluated several lyophilized preparations with scalar receptor content; this permits the identification by linear regression analysis of systematic and non systematic errors. At present 41 laboratories from most of the national regions have joined the Italian Committee. The overall results of five years application of quality assurance in Italy show that there was a different pattern of imprecision with satisfactory indexes for intralaboratory performances but major variations in interlaboratory controls. There was also a remarkable difference of variability indices between the so-called "expert" and "new" laboratories; this problem can be reduced with practical seminars for new centers. On the basis of the results and experience achieved the Committee is starting another program of quality assurance for different new methodologies to provide guidelines for international working reference standards.

Quality control for estrogen and progesterone receptor assay in human breast cancer: the influence of computation methods on intra and interlaboratory variability.

The importance of evaluating receptors for estrogen and progestin in human breast cancer has been pointed out by many authors. In the absence of a reference standard, receptor assays must be controlled by intra and interlaboratory quality control programs. Much interlaboratory variability exists due to non-uniform analytical protocols, non-uniform ligands, intrinsic errors and also errors in computation methods. The goals of our Italian Quality Control Program on Multicenter Trials are to standardize the analytical procedures and computation methods. Twenty Italian laboratories participated in the Quality Control Program. Each specimen was assayed for steroid receptor content according to the standardized dextran-coated-charcoal method. Data were subjected to computerized analyses by 5 different methods of calculation (Scatchard plot, direct plot, Lineweaver-Burk method, Brunauer-Emmet-Teller analysis, single-point approach). The results were than evaluated to identify intra- and inter-assay variation coefficients and to define other statistical parameters. The authors suggest different calculation methods depending on the specific experimental and/or physiopathological conditions.

Results of the Italian interlaboratory quality control program for estradiol receptor assay.

This article presents results of the first Italian quality control program for determining the estradiol receptor on lypophilized guinea pig and calf uteri. Despite considerable variability in quantitative terms, the results concur in ability to define samples as positive or negative for receptor content. One of the parameters that most strongly influences accuracy of determination of receptor concentration is protein assay. The evaluation of several lyophilized preparations at scalar concentrations permitted identification, by linear regression, for each laboratory of the systematic and non-systematic variables. More comparable results will be forthcoming when a standardized methodology program has been fully adopted.

Critical evaluation of ASO RQ-PCR for minimal residual disease evaluation in multiple myeloma. A comparative analysis with flow cytometry.

We have analyzed the applicability, sensitivity and prognostic value of allele-specific oligonucleotide real-time quantitative PCR (ASO RQ-PCR) as a method for minimal residual disease (MRD) assessment in patients with multiple myeloma (MM), comparing the results with those of multiparameter flow cytometry (MFC). A total of 170 patients enrolled in three consecutive Spanish trials achieving at least partial response after treatment were included. Lack of clonality detection (n=31), unsuccessful sequencing (n=17) and suboptimal ASO performance (n=51) limited the applicability of PCR to 42% of cases. MRD was finally investigated in 103 patients (including 32 previously studied) with persistent disease identified by PCR and MFC in 54% and 46% of cases, respectively. A significant correlation in MRD quantitation by both the techniques was noted (r=0.881, P<0.001), being reflective of treatment intensity. Patients with <10(-4) residual tumor cells showed longer progression-free survival (PFS) compared with the rest (not reached (NR) vs 31 months, P=0.002), with similar results observed with MFC. Among complete responders (n=62), PCR discriminated two risk groups with different PFS (49 vs 26 months, P=0.001) and overall survival (NR vs 60 months, P=0.008). Thus, although less applicable than MFC, ASO RQ-PCR is a powerful technique to assess treatment efficacy and risk stratification in MM.

Bent oligonucleotide duplexes as HMGB1 inhibitors: a comparative study.

In this work we explore the ability of a chimeric LNA/DNA bent duplex, in which the kink is induced by 2 unpaired adenines in the middle of one strand, to bind HMGB1, a protein involved in many inflammatory processes. The LNA/DNA duplex was compared with the corresponding full DNA and PNA/DNA chimera duplexes from a thermodynamic and spectroscopic point of view.

[Effect of carbamazepine on free and protein-bound tryptophan in the blood of epileptic patients and healthy volunteers]. / Influenza della carbamazepina sul triptofano libero e legato alle proteine nel plasma di pazienti epilettici e volontari sani.

The Authors estimated the influence of carbamazepine on both free and linked albumin triptofane in the plasma of 6 epileptic patients and of 6 healthy volunteers, during a period of observation lasting 7 days. The relation free/linked triptofane decreased significantly in the epileptic patients after the first day of treatment, while an analogous phenomenon was observed in healthy people only after the seventh day. Part of triptofane disappeared from plasma thus suggesting a cerebral uptake of the synthesis of serotonin. Carbamazepine displaced some unknown compounds from their links with plasmatic albumin, thus allowing triptofane to link itsel. The Authors therefore confirm the role played by anticonvulsive drugs in modifying the pool of free aminoacids in plasma.

Open-flask alkaline hydrolysis of amino acid phenylthiohydantoin derivatives.

It is suggested that the open-flask system for the acid hydrolysis of proteins described earlier can also be used to advantage for the alkaline hydrolysis of amino acid phenylthiohydantoin derivatives obtained in protein sequential analysis according to Edman. Results obtained under nitrogen and argon atmospheres are reported for the hydrolysis of 0.5 mumole of each phenylthiohydantoin derivative, which is the amount of protein that is usually employed in an automatic sequenator.

A new approach for obtaining total tryptophan recovery in plasma samples deproteinized with sulphosalicylic acid.

The treatment of plasma with a sodium dodecy sulphate solution before deproteinization with sulphosalicylic acid is described. With this treatment, the liberation of tryptophan from plasma albumin is complete and its determination can be made directly, together with that of other amino acids and related compounds, by automatic ion-exchange chromatography, eliminating the need for an extra analysis for the accurate determination of this amino acid. Results of tryptophan recovery tests, carried out both on plasma samples simply deproteinized with sulphosalicylic acid and on other samples pre-treated with sodium dodecylsulphate solution are reported. These results are also compared with those obtained when trichloroacetic acid was used as deproteinizing agent. A recovery study on a human albumin (fraction V) solution containing a known amount of tryptophan is also described.

Plasma and cerebrospinal fluid tryptophan in multiple sclerosis and degenerative diseases.

Tryptophan and competing neutral amino acid levels were found to be diminished in the plasma of patients with multiple sclerosis and degenerative diseases, the greatest decrease being of tryptophan. Cerebrospinal fluid tryptophan was decreased in multiple sclerosis and motor neurone disease, while leucine and valine were increased. These changes might lead to decreased synthesis of brain serotonin and brain proteins. The ratio between neutral amino acids and tryptophan might be used as an ancillary test in the screening of degenerative diseases.

Cyclic adenosine-3':5'-monophosphate binding proteins in human mammary tumor cytosol and their relation to estrogen and progesterone receptors. A preliminary study.

A method for determining cAMP-binding activity in human mammary tumor cytosol is described and the results of routine assay on 57 tumor samples are presented in relation to the estrogen and progesterone receptor levels. Results show that the values of each single parameter are very largely dispersed. The estrogen receptor/cAMP-binding protein ratio distributes in a very interesting way, in view of a retrospective clinical trial now in progress.

Short-term results of hydroxyapatite-coated primary total hip arthroplasty.

One hundred consecutive patients who had Howmedica ABG total hip replacements, a system in which the femoral stem and the acetabular component are hydroxyapatite coated, during the period from September 1989 to January 1991 were studied prospectively. Clinical assessment using the d'Aubigné score showed that 96 patients had an excellent score at a minimum of 2 years from the operation. Radiographic analysis, based on DeLee and Charnley criteria for the acetabular cup and on Gruen criteria for the femoral stem, showed equally good results. There was good initial stability of the cup and the metaphyseal portion of the stem, with a secondary increase of load transmission in Zones 2 and 6 with cortical and cancellous thickening.

Thigh pain in cementless hip replacement. Clinical and radiographic correlations.

The authors analyse a series of 35 Rippen System cementless hip joint prostheses implanted in 32 patients from May 1987 to September 1988. Certain radiographic parameters were studied in an attempt to find a correlation with the clinical results. Special attention was paid to the high incidence of thigh pain, attempting to identify the cause through radiographic study of the bone-implant interface. Even when analyzed using Kappa statistics, the correlation between the clinical and radiographic findings was purely incidental. In agreement with the literature, the authors identify some elements which should be investigated further such as primary temporary fixation of the stem, reduction of micromotion, and biocompatibility of the materials.