DDP1, a single-stranded nucleic acid-binding protein of Drosophila, associates with pericentric heterochromatin and is functionally homologous to the yeast Scp160p, which is involved in the control of cell ploidy

The centromeric dodeca-satellite of Drosophila forms altered DNA structures in vitro in which its purine-rich strand (G-strand) forms stable fold-back structures, while the complementary C-strand remains unstructured. In this paper, the purification and characterization of DDP1, a single-stranded DNA-binding protein of high molecular mass (160 kDa) that specifically binds the unstructured dodeca-satellite C-strand, is presented. In polytene chromosomes, DDP1 is found located at the chromocentre associated with the pericentric heterochromatin but its distribution is not constrained to the dodeca-satellite sequences. DDP1 also localizes to heterochromatin in interphase nuclei of larval neuroblasts. During embryo development, DDP1 becomes nuclear after cellularization, when heterochromatin is fully organized, being also associated with the condensed mitotic chromosomes. In addition to its localization at the chromocentre, in polytene chromosomes, DDP1 is also detected at several sites in the euchromatic arms co-localizing with the heterochromatin protein HP1. DDP1 is a multi-KH domain protein homologous to the yeast Scp160 protein that is involved in the control of cell ploidy. Expression of DDP1 complements a Deltascp160 deletion in yeast. These results are discussed in view of the possible contribution of DNA structure to the structural organization of pericentric heterochromatin.

[Rol of thallium-201/gallium-67 cerebral tomogammography in the differential diagnosis of cerebral space occupying lesions]

INTRODUCTION

Central nervous system (CNS) neoplasms are 10% of all tumors. A metastasis of an unknown primary neoplasm should be suspected in an adult with a cerebral tumor. In this location, the origin of most of metastases (62%) is lung, breast, skin and kidney. However, a differentiation of CNS focal infection and brain tumor, based on clinical status and morphologic imaging, may be difficult. A positive Tl-201 next to a negative Ga-67 SPECT brain scans is entirely in accord with brain metastatic tumor.

CLINICAL CASE

A 72-year-old man, with history of excised bladder cancer, was admitted for neurological symptoms associated with a left occipital mass demonstrated by cranial CT and brain MRI. Clinicoradiological findings suggested a neoplastic process. Two cerebral biopsies just showed inflammatory cells. Tl-201 and Ga-67 SPECT brain scans were performed and their findings, an abnormal uptake of Tl-201 in the left occipital cortex and a negative Ga-67 scan, favored a neoplastic process. Radical exeresis of the lesion showed a metastatic adenosquamous carcinoma of probably lung origin.

CONCLUSION

Tl-201 in addition to Ga-67 brain SPECT scans are a valuable tool for differential diagnosis between cerebral infection and brain tumour in patients with a sole cerebral mass lesion, especially when clinicoradiological findings and biopsy results are conflicting.

Structural basis of substrate specificity in malate dehydrogenases: crystal structure of a ternary complex of porcine cytoplasmic malate dehydrogenase, alpha-ketomalonate and tetrahydoNAD

The structural basis for the extreme discrimination achieved by malate dehydrogenases between a variety of closely related substrates encountered within the cell has been difficult to assess because of the lack of an appropriate catalytically competent structure of the enzyme. Here, we have determined the crystal structure of a ternary complex of porcine cytoplasmic malate dehydrogenase with the alternative substrate alpha-ketomalonate and the coenzyme analogue 1,4,5,6-tetrahydronicotinamide. Both subunits of the dimeric porcine heart, and from the prokaryotes Escherichia coli and Thermus flavus. However, large changes are noted around the active site, where a mobile loop now closes to bring key residues into contact with the substrate. This observation substantiates a postulated mechanism in which the enzyme achieves high levels of substrate discrimination through charge balancing in the active site. As the activated cofactor/substrate complex has a net negative charge, a positive counter-charge is provided by a conserved arginine in the active site loop. The enzyme must, however, also discriminate against smaller substrates, such as pyruvate. The structure shows in the closed (loop down) catalytically competent complex two arginine residues (91 and 97) are driven into close proximity. Without the complimentary, negative charge of the substrate side-chain of oxaloacetate or alpha-ketomalonate, charge repulsion would resist formation production of this catalytically productive conformation, hence minimising the effectiveness of pyruvate as a substrate. By this mechanism, malate dehydrogenase uses charge balancing to achieve fivefold orders of magnitude in discrimination between potential substrates.

Enhancement of resistance in mice treated with Lactobacillus casei: effect on Trichinella spiralis infection

The ability of viable Lactobacillus casei, administered by an intraperitoneal route, to induce resistance in mice against Trichinella spiralis infection was tested. The percent reduction of adult worms in the intestine 5 days after T. spiralis infection observed in L. casei-treated animals, compared with those of the control group, fluctuated between 70.9 and 88.5%; reductions of larvae per gram of muscle tissue, evaluated at 30 days after infection, varied from 46.6 to 84.4% in L. casei-treated mice compared with controls. At 5 days after infection, intestinal villus height was shorter in T. spiralis-infected animals than in L. casei-treated or uninfected mice. There were fewer mast cells/crypt unit in L. casei-treated and uninfected mice than in T. spiralis-infected animals. Lactobacilli-treated mice showed twice as many mononuclear cells/crypt unit as T. spiralis-infected animals. The IFN-gamma serum level was higher in L. casei-treated animals at the time of worm challenge as compared with T. spiralis-infected or uninfected mice. The results indicate that: (1) L. casei increased resistance that acted against T. spiralis infection in mice, (2) this resistance apparently was directed against adult worms in the intestine.

[Swallowing changes in cerebrovascular accidents: incidence, natural history, and repercussions on the nutritional status, morbidity, and mortality]

OBJECTIVE

To determine the frequency of dysphagia in CVA, its natural history and value as a risk factor of respiratory infection, malnutrition and death.

PATIENTS AND METHODS

A prospective study was made of 187 consecutive patients with cerebrovascular accidents (CVA). A standardized test for dysphagia was done during the first two days of the illness and repeated three days a week. The levels of urea, total proteins and albumin were determined on admission and on discharge. The patients were questioned by phone after 6 months.

RESULTS

There was dysphagia of liquids in 36.4% of the patients. The incidence of dysphagia for semisolids was of the same frequency but more severe. Coma was the cause of inability to swallow in 25.7% of the patients. During their stay in hospital one third of the patients with dysphagia died, one third became normal and one third still had dysphagia when they were discharged. After one week, one, three and six months respectively, the cure rate for dysphagia was 29.4%, 4.1%, 55.9% and 55.9%, and survival 83.8%, 67.6%, 61.8% and 60.3%. Thus after 6 months only 3 patients (4.4%) were alive and dysphagic. Half of the 'cures' occurred in the first week, and none occurred after more than 77 days. As compared to the non-dysphagic patients, the dysphagic patients had 10 times more risk of respiratory infection, 18 times higher risk of death, greater loss of albumin and less loss of urea.

CONCLUSIONS

There is a high prevalence of dysphagia in CVA and although functional prognosis is not unfavorable, respiratory infections, malnutrition and death are frequent.

Uptake of I-131 in the biliary tract: a potential cause of a false-positive result of scintiscan

Focal uptake of I-131 in the region of the liver was seen on whole-body scans in a 22-year-old asymptomatic woman who had invasive papillary cancer. Hepatic metastases were unlikely because of the clinical risk factors, and a CT scan of the liver was normal. By superimposing the I-131 scintiscan and a hepatobiliary scan, the site of the uptake was shown to be in the biliary tract, and it had migrated to the gallbladder on more delayed images. No pathologic cause was found.

[Report on the activity of the blood bank accreditation program (1987-1995)]

PURPOSE

To show the incidence of the deficiencies detected in the Blood Banks for the accreditation by the Transfusion Accreditation Committee (CAT), previously named PABAS.

MATERIALS AND METHODS

Analysis of the reports of the accreditation of 85 Blood Banks made by the PABAS during the period 1987-1995.

RESULTS

Eighty-five (20.8%) of the 407 Community Blood Centers, Hospital-Based Blood Banks and Transfusional Services of Spain had been surveyed. There were 244 deficiencies, of which 31 (12.7%) were of the equipment, 114 (46.7%) of the procedures used, and 99 (40.6%) of the documentation. The activities with more incidence of faults were: Control of the temperatures of the storage of units 53 (21.7%), label of the components 38 (15.5%), quality system of the institution surveyed 32 (13.1%), transfusional procedures 30 (12.3%), and on the procedure of the selection of donors 29 (11.9%). By contrary, the areas of work with fewer incidences of faults were those related with the collection of the blood and components 10 (4.1%) and the laboratory 14 (5.7%).

CONCLUSIONS

Low percentage of the Community Blood Centers, Hospital-Based Blood Banks and Transfusional Services, which ask to be accredited by the Transfusion Accreditation Committee. The 83.7% of the errors detected are of the procedures and documentation, which could be easily corrected by the training and continuous improving of the quality, and without need of new inversions in equipment.

Tandem 5'-GA:GA-3' mismatches account for the high stability of the fold-back structures formed by the centromeric Drosophila dodeca-satellite

The centromeric dodeca-satellite of Drosophila forms unusual DNA structures in which its purine-rich strand (GTACGGGACCGA)n folds into very stable intramolecular hairpins. These intramolecular hairpins contain groups of tandem 5'-GA:GA-3' mismatches that, as judged by gel electrophoresis analysis and UV-melting studies, have a determinant contribution to their stability. Duplexes of the dodeca-satellite purine-rich strand, carrying tandem 5'-GA:GA-3' mismatches, are as stable as equivalent fully Watson-Crick duplexes containing tandem 5'-TA:TA-3' Watson-Crick pairs in place of the non-Watson-Crick G.A pairs. On the other hand, duplexes carrying any of the other three possible tandem combinations of purine.purine mismatches, including G.A pairs on the opposite orientation 5'-AG:AG-3', are very unstable. The high stability of the dodeca-satellite hairplus suggests that the tandem G.A pairs are on the sheared configuration although they are found within the less favourable 5'-G-(G-A)-C-3' sequence context. Other centromeres DNA sequences, including the AAGAG satellite of Drosophila and the mammalian CENP-B box sequence, have the potential of forming intramolecular hairpins stabilised by similar purine.purine interactions.

Auricular chromoblastomycosis caused by Rhinocladiella aquaspersa

An unusual case of chromoblastomycosis localized in the ear and caused by R. aquaspersa is presented. The patient was a 60-year-old male urban resident, who had had the disease for 5 years. The lesion was darkly pigmented, infiltrative and crusty. Sclerotic cells were seen on direct examinations and the fungus was recovered in culture and identified on the basis of the characteristic sporulation. Itraconazole therapy at a dose of 200 mg day-1 for 7 months produced complete healing.

Optimisation of the prescription for trans-tibial (TT) amputees

The great diversity of prosthetic mechanisms available nowadays leads to the question of which type of artificial foot would be the most advisable for a particular person. To answer correctly, it is necessary to establish, in an objective way, the performance of each type of prosthetic mechanism. This knowledge is obtained by means of the study of the subject-prosthesis interaction, both in static and dynamic conditions. This paper, based on the analysis of 8 trans-tibial (TT) amputees, presents a quantitative method for the study of human gait which allows the determination of the influence of four different prosthetic ankle-foot mechanisms (SACH, Single-axis, Greissinger and Dynamic) on gait. To do this, 1341 gait trials at different cadences were analysed (383 with normal subjects and 958 with amputees, using the four prosthetic feet under study). From all the variables available for study only those which offered interpretable clinical information were chosen for analysis. A total of 18 variables (kinetic, kinematic and time-related) were selected. A covariance analysis (ANOVA) of these variables was made, which showed that the factors influencing TT amputee gait were, in order of importance, cadence and leg studied (sound or prosthetic), inter-individual variability and, finally, the prosthetic mechanism used. When looking at the performance during gait of the 4 prosthetic mechanisms studied it can be observed that there are similarities in the kinetic study between SACH and Dynamic feet on one hand and Single-axis and Greissinger feet on the other. These results seem to support the classification criteria of articulated and non-articulated prosthetic mechanisms.

Bronchial epithelium associated to lymphoid tissue does not selectively express vimentin

The existence of a lymphoepithelium containing M cells in the bronchus-associated lymphoid tissue (BALT) of several species has repeatedly been questioned. In previous electron microscopical studies we failed to ultrastructurally identify these cells in the epithelium covering bronchial lymphoid tissue of adult rats. In the present study, we analyze immunohistochemically the expression of vimentin, an intermediate filament, reported to be a sensitive marker for rabbit M cells, in both BALT and Peyer's patches. Our results demonstrate, however, the absence of vimentin expression in the epithelium covering the bronchial lymphoid aggregates as well as in the lymphoepithelium of the Peyer's patches. On the contrary, both epithelia are strongly cytokeratin positive. Furthermore, numerous vimentin-positive lymphocytes appear in both lymphoid organs. Results are discussed from a view of the possible relationship between BALT and the so-called mucosae-associated lymphoid tissue (MALT).

D-2-hydroxy-4-methylvalerate dehydrogenase from Lactobacillus delbrueckii subsp. bulgaricus. I. Kinetic mechanism and pH dependence of kinetic parameters, coenzyme binding and substrate inhibition

The steady-state kinetics of D-2-hydroxy-4-methylvalerate dehydrogenase have been studied at pH 8.0 by initial velocity, product inhibition, and dead-end inhibition techniques. The mechanism is rapid-equilibrium ordered in the NAD+ plus D-2-hydroxy-4-methylvalerate direction, and steady-state ordered in the other direction. In both cases coenzyme is the first substrate added and both the E-NADH-D-2-hydroxy-4-methylvalerate and E-NAD+-2-oxo-4-methylvalerate give rise to abortive complexes which cause excess substrate inhibition. Steady-state measurements show that the rate-limiting step in both directions at pH 8.0 is between formation of the enzyme-coenzyme-substrate ternary complex and the release of the first product of the reaction. Transient kinetics combined with primary kinetic deuterium isotope effects show that in the NADH-->NAD+ direction there is a slow, rate-limiting rearrangement of the E-NADH-oxoacid complex while hydride transfer is very fast. The release of NAD+ at pH 8.0 is 200-times faster than Kcat (NADH-->NAD+) whereas the release of NADH is only 5-times faster than Kcat (NAD+-->NADH). The pH dependence of NADH binding depends upon the presence of two ionizable residues with a pKa of about 5.9. The pH dependence of kinetic parameters is explained by a third ionizable residue with pKa values 7.2 (in the E-NADH complex) and < or = 6.4 (in the E-NAD+ complex) which may be the proton donor and acceptor for the chemical reaction. At pH 6.5 the mechanism changes in the NADH-->NAD+ direction to be partly limited by the chemical step with a measured primary kinetic isotope effect of 5.7 and partly by an only slightly faster dissociation of NAD+. In addition the inhibition by excess oxo-4-methylvalerate is more pronounced. The mechanism implies that removing the positive charges created by the two groups which control coenzyme affinity could both enhance the catalytic rate at pH 6.5 and diminish excess substrate inhibition to provide an enzyme better suited to the bulk synthesis of D-2-hydroxyacids.

Cloning, sequencing and functional expression of a DNA encoding pig cytosolic malate dehydrogenase: purification and characterization of the recombinant enzyme

Using the polymerase chain reaction, DNA encoding cytosolic malate dehydrogenase (cMDH) has been cloned from a pig heart cDNA library. Large amounts of the enzyme (30 mg per litre of original culture) have been produced in Escherichia coli using an inducible expression vector (pKK223-3) in which the 5'-non-coding region of the gene was replaced with the tac promoter. The complete nucleotide sequence of the DNA is reported for the first time. The recombinant cMDH purified was shown to be identical to the native enzyme according to: chromatographic behaviour, isoelectric point, N-terminal amino acid sequence, and physiochemical and catalytic properties.

Prognosis for fertility analyzing different variables in men and women

A cohort of 123 infertile couples was studied by life tables over a 30-month follow-up period to determine the influence on reproductive prognosis of clinical features, namely the women's age, previous gestational events, evolution time, and a number of conditioning infertility factors. The cumulative pregnancy rate (CPR) was 60% at 30 months. Women aged 32 years or less had a CPR of 65% and those over 32 years had a CPR of 31%. Couples with previous pregnancy had a CPR of 88%, while those with primary infertility had a CPR of 45% (marginal statistical difference). The group with infertility evolution of 36 months or less had a CPR of 75% and those with greater than 36 months infertility evolution had a CPR of 43% (p < .05). With one conditioning infertility factor a CPR of 75% was found, and with multiple factors a CPR of 47% (p < .05) was found. With these results a grading chart was created using all the analyzed criteria, determining the proportion of pregnancies per number of negative points obtained; at greater grades the proportion of pregnancy was reduced (p < .01). This report establishes the prognostic value of different variables observed in the evaluation of infertile men and women, and a simple procedure to calculate the probability to achieve pregnancy is proposed.

T-dependent areas in the chicken bursa of Fabricius: an immunohistological study

BACKGROUND

The so-called diffusely infiltrated lymphoid tissue of the chicken bursa of Fabricius was previously described as a T-dependent bursal area.

METHODS

We have analyzed immunohistologically its postnatal development by using a battery of mAbs, most of them raised specifically to chicken T cells, in order to characterize phenotypically the nature of its cell components, appearance, development, and possible functional significance.

RESULTS

Our results demonstrate that this tissue represents poorly developed lymphoid aggregates, the cell content reminiscent of that found in other lymphoid tissues occurring throughout the avian gut. The first lymphoid elements appear in this bursal area only after hatching, growing rapidly to reach the adult condition in the second week of postnatal life. They consist mainly of T lymphocytes, including principally. CD4+ TcR alpha V beta 1+ cells, which form cell groups and CD8+ cells, and TcR gamma delta+ lymphocytes, which predominate in the subepithelial area and within the epithelium. MHC Class II molecule-expressing cells and IgM-, IgG-, and IgA-positive B lymphocytes also occupy the subepithelial region.

CONCLUSIONS

We propose that the bursal diffusely infiltrated lymphoid tissue of the chicken represents gut-associated lymphoid tissue involved in mounting immune responses to antigens that reach the bursal lumen via the cloaca.

Antibodies to hepatitis C virus: a cross-sectional study in patients attending a trauma unit or admitted to hospital for elective surgery

OBJECTIVE

To assess the prevalence of hepatitis C virus (HCV) antibodies in patients attending a trauma unit or admitted to hospital for elective surgery, and to identify risk factors for acquiring HCV infection.

DESIGN

A cross-sectional study.

SETTING

The emergency room of a Department of Orthopaedic Surgery and a hospital for elective (non-digestive) surgery.

PATIENTS

A study population of 1824 subjects (mean age 40.1 +/- 18.1 years) and sera from a control group of 4703 blood donors giving their first donation.

INTERVENTIONS

Serum samples were screened for HCV antibodies by second-generation enzyme-linked immunosorbent assays and recombinant immunoblot assays.

MAIN OUTCOME MEASURES

HCV serostatus and the relationship between anti-HCV-positivity and age, intravenous drug use, tattoos, blood transfusion, a history of hepatitis and exposure to a contact who had had hepatitis.

RESULTS

The overall prevalence of anti-HCV antibodies was 2.85% in the study population and 0.5% among blood donors (chi 2 = 64.5; P < 0.0001). Anti-HCV-positivity was more common in men (3.8 versus 1.9%; P < 0.05) and in subjects with history of hepatitis (13.5 versus 2.0%; P < 0.001), exposure to a contact who had had hepatitis (12.5 versus 1.9%; P < 0.001), blood transfusion (7.8 versus 2.3%; P < 0.001), tattoos (36 versus 2.4%; P < 0.001) and intravenous drug use (85.7 versus 1.9%; P < 0.001). However, one third of subjects had no risk factors for HCV infection. The logistic regression analysis confirmed a statistically significant association (P < 0.05) between anti-HCV-positivity and intravenous drug use, tattoos, blood transfusion, a history of hepatitis and exposure to a contact who had had hepatitis.

CONCLUSIONS

These results show almost a five-fold higher prevalence of anti-HCV among patients attending a trauma unit or admitted to hospital for elective surgery than among blood donors.

[Long-acting and repeatable dose bromocriptine in the prolonged treatment of prolactinoma]

BACKGROUND

The presentations of intravenous or depot bromocriptine (bromocriptine LA or long acting, Pariodel LA and bromocriptine LAR or long acting repeatable, Pariodel LAR) have improved the efficacy and the tolerance of oral bromocriptine. In contrast to bromocriptine LA, bromocriptine LAR may be repeatedly administered intramuscularly.

METHODS

Five patients with macroprolactinoma and 4 with microprolactinoma were included in the study. A 50 mg bottle of bromocriptine LAR was administered intramuscularly every month, over a minimum period of 6 months. PRL was determined prior to the study, 1, 3, 7, 14, and 28 days following the initial dose of bromocriptine and thereafter with monthly periodicity.

RESULTS

The PRL values decreased in those patients with macroprolactinomas following the administration of bromocriptine LAR; in 2 patients the monthly doses of bromocriptine LAR was increased to 100 mg since the month after the initial dose PRL remained greater than 200 ng/ml with serum RPL normalizing in most of the patients at 6 months of treatment. In two of the three patients who presented visual changes a clear improvement was observed and in all the cases a reduction in the size of the macroprolactinoma was found upon CAT control at 6 months. The PRL values also decreased in the patients with microprolactinomas following administration of bromocriptine LAR, although the response was not as homogeneous as in the patients with macroprolactinomas due to that at 6 months 2 patients continued to have slightly elevated serum PRL levels. The microadenoma persisted in the control CAT at 6 months except in one case. Local and general tolerance to bromocriptine LAR was very good.

CONCLUSIONS

This study indicates good tolerance to bromocriptine LAR, being a therapeutic option in the treatment of macroprolactinomas.

Contribution of a buried aspartate residue towards the catalytic efficiency and structural stability of Bacillus stearothermophilus lactate dehydrogenase

The X-ray structure of lactate dehydrogenase (LDH) shows the side-chain carboxylate group of Asp-143 to be buried in the hydrophobic interior of the enzyme, where it makes hydrogen-bonding interactions with both the side-chain hydroxyl group of Ser-273 and the main-chain amide group of His-195. This is an unusual environment for a carboxylate side-chain as hydrogen bonding normally occurs with water molecules at the surface of the protein. A charged hydrogen-bonding interaction in the interior of a protein would be expected to be much stronger than a similar interaction on the solvent-exposed exterior. In this respect the side-chain carboxylate group of Asp-143 appears to be important for maintaining tertiary structure by providing a common linkage point between three discontinuous elements of the secondary structure, alpha 1F, beta K and the beta-turn joining beta G and beta H. The contribution of the Asp-143 side-chain to the structure and function of Bacillus stearothermophilus LDH was assessed by creating a mutant enzyme containing Asn-143. The decreased thermal stability of both unactivated and fructose-1,6-diphosphate (Fru-1,6-P2)-activated forms of the mutant enzyme support a structural role for Asp-143. Furthermore, the difference in stability of the wild-type and mutant enzymes in guanidinium chloride suggested that the carboxylate group of Asp-143 contributes at least 22 kJ/mol to the conformational stability of the wild-type enzyme. However, there was no alteration in the amount of accessible tryptophan fluorescence in the mutant enzyme, indicating that the mutation caused a structural weakness rather than a gross conformational change. Comparison of the wild-type and mutant enzyme steady-state parameters for various 2-keto acid substrates showed the mutation to have a general effect on catalysis, with an average difference in binding energy of 11 kJ/mol for the transition-state complexes. The different effects of pH and Fru-1,6-P2 on the wild-type and mutant enzymes also confirmed a perturbation of the catalytic centre in the mutant enzyme. As the side-chain of Asp-143 is not sufficiently close to the active site to be directly involved in catalysis or substrate binding it is proposed that the effects on catalysis shown by the mutant enzyme are induced either by a structural change or by charge imbalance at the active site.(ABSTRACT TRUNCATED AT 400 WORDS)

The stability and hydrophobicity of cytosolic and mitochondrial malate dehydrogenases and their relation to chaperonin-assisted folding

mMDH and cMDH are structurally homologous enzymes which show very different responses to chaperonins during folding. The hydrophilic and stable cMDH is bound by cpn60 but released by Mg-ATP alone, while the hydrophobic and unstable mMDH requires both Mg-ATP and cpn10. Citrate equalises the stability of the native state of the two proteins but has no effect on the co-chaperonin requirement, implying that hydrophobicity, and not stability, is the determining factor. The yield and rate of folding of cMDH is unaffected while that of mMDH is markedly increased by the presence of cpn60, cpn10 and Mg-ATP. In 200 mM orthophosphate, chaperonins do not enhance the rate of folding of mMDH, but in low phosphate concentrations chaperonin-assisted folding is 3-4-times faster.

[Outbreak of measles at a vocational training school]

BACKGROUND

A measles outbreak which started in the technical institute Els Ports in Albocacer (Castellón), and involved nearby towns was studied.

METHODS

The outbreak was described using a retrospective cohort study to estimate the efficacy of the antimeasles vaccination (EV) by a questionnaire distributed in the institute. Response rate was 80.7%. A clinical definition of measles was used with EV being calculated by 2 different formulas. Antimeasles vaccination coverage (VC) in primary schools of the towns involved was also assessed.

RESULTS

The outbreak occurred from February to April 1992, including 13 cases of measles (mean age: 13.6 +/- 2.7 years). Eleven patients (84.6%) had not been vaccinated. The attack rate the above mentioned institute was 9.1% (8 cases/88 students) with VC of 40.9%. An association was found only between being vaccinated and not having measles, relative risk 0.07 (confidence limits [CL] 95%: 0.01-0.50). EV was 92.9% (CL 95%: 50-99%) using the traditional formula and 96.2% (CL 95%: 88.2-100%) using the new formula. The VC in the schools was 92.3%. Vaccination with the triple viral vaccine was recommended to susceptible individuals.

CONCLUSIONS

Despite specific vaccination measles continues to produce epidemics. A second dose of the triple viral vaccine is recommended for being included in the vaccination calendar between the age of 6 and 14 years.

Intrafamilial spread of hepatitis C virus infection

We assessed the prevalence of antibodies to hepatitis C virus (anti-HCV) among 401 household contacts of 161 persons with chronic hepatitis C (index patients). None of the index patients had antibodies against HIV. The overall prevalence of anti-HCV was 3.2% (2.5% in the absence of previous parenteral exposure). Sexual partners had a seroprevalence of 4.7% and non-sexual contacts, 2.5%. Among non-sexual contacts, parents showed the highest rate (4.2%). The mean duration of exposure in the anti-HCV-positive sexual partners was 17.3 +/- 8.5 years, vis-à-vis 9.2 +/- 7.4 years in the anti-HCV-negative sexual partners. We conclude that there is little risk of HCV infection through household contact. Although the form of transmission is not well identified, the duration of sexual activity suggests that the time needed to become infected is long.

Clinical use of octreotide in unresectable meningiomas. A report of three cases

Unresectable meningioma is the cause of a serious clinical problem, for whom no satisfactory mode of treatment is currently available. Meningiomas are known to have receptors for diverse hormones. In this sense, somatostatin receptors were found in every meningioma specimen studied in a recent report. In addition, somatostatin has been able to inhibit meningioma cell proliferation in vitro. A brief report of clinical use of somatostatin long-life analogue octreoctide upon three patients diagnosed of unresectable meningioma is here presented. Doses used were gradually increased up to 1000, 900 and 1500 micrograms/24 h during 16, 6 and 7 weeks, respectively. There was an almost perfect tolerance to the drug (in one case a mild and transient abdominal discomfort and diarrhea could be observed). An important alleviation of headaches in 2 cases, and a transient but objective improvement in ocular movements and signs in 1 case were noticed. No change (neither growth nor shrinkage) was observed by CT scan at the end of treatment course in the three cases studied. In 1 case a partial resection was performed and tissue specimen was found to contain somatostatin receptors. Although in our very limited experience no brilliant results are presented, duration of treatment or doses used could have been insufficient. Data herein presented seem to support recently reported findings in which no growth inhibition of meningioma cells cultured in vitro by adding octreoctide to the medium was observed. So, in our opinion, clinical use of octreoctide on unresectable meningioma deserves further experience, that must be carried out with great caution.

Kinetic studies of the regulation of mitochondrial malate dehydrogenase by citrate

Mitochondrial malate dehydrogenase shows a complex regulation pattern in the presence of citrate. Previously published results indicate that this enzyme is activated by citrate in the NAD(+)----NADH direction and inhibited in the opposite direction. Moreover, high concentrations of L-malate or oxaloacetate produce deviations from the Michaelis-Menten behaviour. Results reported in this paper clearly show that citrate both activates and inhibits mitochondrial malate dehydrogenase in the same direction (NAD(+)----NADH), and in the same reaction medium, depending on substrate concentration. This surprising effect has made it necessary to propose a new kinetic mechanism that extends those previously suggested and allows us to explain both the citrate effect (activating or inhibitory) and the effect of high concentrations of L-malate and oxaloacetate.

Heterogeneity of human liver alanine aminotransferase due to sulfhydryl groups oxidation

The cytosolic isoenzyme of human liver alanine aminotransferase exhibited a progressive change in its chromatographic behavior on DEAE-Sepharose when partially purified preparations were stored for up to 8 days at 4 degrees C. This change was characterized by the appearance of an additional chromatographic variant and was avoided by addition of 2-mercaptoethanol. The experimental evidence presented indicates that the progressive oxidation of free sulfhydryl groups of the enzyme is responsible for the charge modifications and heterogeneity observed.

Heterogeneity of chicken liver cytosolic aspartate aminotransferase

The isolated native molecular forms of chicken liver cytosolic aspartate aminotransferase give rise to two kinds of generation processes: (a) on storage, molecular forms are transformed into a series of variants with increasing anodic mobilities; and (b) addition of thiol reagents not only avoids the process, but causes the partial transformation of minor subforms into variants with higher isoelectric point values. In both cases the mobilities of each generated variant coincide with that of the corresponding native molecular form. The variants generated either by storage or in the presence of thiol reagents were separated by chromatofocusing. Several comparative studies have demonstrated the structural and functional identity between native molecular forms and 'in vitro' active generated variants of the enzyme. The results obtained suggest that native minor subforms arise from the major alpha form due to oxidation process and might represent intermediate species in the intracellular cytosolic aspartate aminotransferase turnover.

A rapid procedure for eliminating chromatofocusing buffer and concentrating minor active subforms of mitochondrial malate dehydrogenase

Mitochondrial malate dehydrogenase from several sources contains different molecular forms whose origin is still under discussion. Separation of these subforms has been achieved by chromatofocusing. A simple and rapid method, based on 5' AMP Sepharose chromatography, has been developed to concentrate mitochondrial malate dehydrogenase subforms and simultaneously remove chromatofocusing buffer.

[Response to recombinant DNA antihepatitis B vaccine in mentally retarded patients with Down's syndrome. A controlled study]

To investigate the response of mentally retarded individuals (MR) with Down's syndrome (Down-MR) to recombinant hepatitis B vaccine, three doses (20 micrograms per dose) were administered on the usual schedule (months 0, 1 and 6) to two groups of MR with mean age of 14.6 years. The first group consisted of 32 MR-Down. The second group consisted of 35 MR other etiologies (non Down-MR). Both had the same sex distribution and similar ages and weight/height index. The post vaccination anti-HBs titers were measured on months 1, 2, 6 and 8. The results could be analysed in 63 MR. Eight months after vaccination, 100% of Down-MR and 91% of non Down-MR developed a response to the vaccine (anti-HBs greater than 10 IU/l). Both groups achieved high antibody titers (geometric mean 4.298 and 6.424, respectively). A significant inverse correlation of anti-HBs with age was found, but not with sex of with the weight-height index. It was concluded that Down-MR in young age have a normal response to recombinant hepatitis B vaccine at the usual dose and schedule. Therefore, the goal to suppress the reservoir of hepatitis B in Down-MR both in institutions for MR and in normal schools should be achieved.

[Treatment of macroprolactinomas with delayed bromocriptine. Effectiveness of a single intramuscular injection]

The aim of the present study was to evaluate the effectiveness and tolerance of a new pharmaceutical preparation of long acting bromocryptine (bromocryptine depot of L.A.), characterized by the slow release of bromocryptine during 4 or 6 weeks after a deep intramuscular injection. It was administered to 9 patients with macroprolactinoma, 7 of which had visual abnormalities. The tolerance of the drug was excellent, and only one patient had nausea within the first 24 hours. In all cases, PRL values fell between 40% and 97%. All patients with visual abnormalities, including 2 patients with cranial nerve palsy (IIIth and VIIth pairs) returned to normal or improved. In the CT controls carried out after 4 weeks of therapy a reduction in tumor size was observed in 7 of 9 patients. Two patients were operated through the transesphenoidal route, PRL being demonstrated in the immunohistochemical study of the resected specimen. Subsequently, all patients received oral bromocryptine therapy with perfect tolerance. The results show that parenteral long acting bromocryptine is an effective, well tolerated and convenient way to start the therapy of macroprolactinoma, even when severe visual abnormalities are present.

Comparative analysis of the reduction of oxaloacetate by human hepatoma and normal liver extracts

An apparent activation of the malate dehydrogenase activity is observed in the double-reciprocal plot at high oxaloacetate concentrations when human hepatoma extracts are analyzed. This phenomenon does not occur in healthy liver samples. In hepatoma extracts, the ratio of lactate dehydrogenase to malate dehydrogenase activities becomes five-fold higher than that of normal liver. Experiments performed with mixtures of both purified enzymes and, conversely, by using oxamate, a specific inhibitor of lactate dehydrogenase, reveal that the deviation in Michaelis-Menten behavior observed is due to the oxaloacetate reductase activity of lactate dehydrogenase instead of the presence of a novel malate dehydrogenase isoenzyme.

Kinetic formulations for the reduction of ketomalonate by lactate dehydrogenase

Initial rate kinetic studies of lactate dehydrogenase with ketomalonate and NADH as substrates suggest that this enzymatic system is adapted to a rapid equilibrium ordered bi-bi ternary complex mechanism. The application of the reaction product inhibition method reveals the existence of the enzyme-NADH-hydroxymalonate and enzyme-NAD(+)-ketomalonate abortive complexes. This kinetic behaviour is confirmed by the differential inhibition induced by several alternate products on the pyruvate-lactate dehydrogenase-NADH and ketomalonate-lactate dehydrogenase-NADH systems.

[Mentally deficient patients and infection caused by hepatitis B virus. Prevalence in our area]

To assess the prevalence of hepatitis B virus (HBV) infection in medium level mentally impaired patients (MIP), 620 MIP were evaluated; 181 of them had Down's syndrome and were active inmated of open institutions. At the time of the study, 28.7% had some positive serum marker of HBV infection, and 5.8% were virus carriers. The highest rate of seropositive individuals (48%) was found in male MIP with Down's syndrome. The rate of seropositive individuals was higher among those MIP who had attended special education centers than in those who had not. The tendency to remain as HBV carrier was higher in males with Down's syndrome. Our results confirm the need for prophylaxis in this population.

Purification and characterization of chicken brain cytosolic aspartate aminotransferase

Aspartate aminotransferase from the cytosolic fraction of chicken brain was isolated with acceptable yield and high degree of purity. The enzyme appeared in multiple molecular forms: alpha, beta, gamma, and delta (alpha predominates), as detected by polyacrylamide gel electrophoresis with specific staining. These different forms of the enzyme were separated by DEAE-Sephacel chromatography, and showed different isoelectric points and maximal velocities values, whereas their molecular weight, optimum pH and Michaelis constants were very similar. Generation process studies suggest that minors subforms of the enzyme could be raised from alpha form by a mechanism in which the oxidation of particular amino acid groups are involved.

Cytosolic aspartate aminotransferases from different chicken tissues: purification and characterization of their multiple forms

Cytosolic aspartate aminotransferases from chicken heart, liver, spleen, skeletal muscle and breast muscle differed in number of their molecular forms, detected by polyacrylamide gel electrophoresis and specific staining. The number of molecular forms varied from tissue to tissue but the electrophoretic mobilities of a given form in all tissues were analogous. Within a single tissue most of the enzyme activity was present as the lowest-running band (alpha form) and the rest was distributed in minor bands termed (B,tau, alpha and epsilon forms). We report a method for the purification of cytosolic aspartate aminotransferases from various chicken tissues. The procedure can be carried out in one week and allows the obtention of isolated molecular forms of the enzyme, independently of the tissue under study. Separation of multiple forms was also achieved by chromatofocusing. The isoelectric points determined by this method for a given form in all five tissues were analogous and differed from those of the molecular forms of the enzyme from other origins. An Mr of 100,000 was obtained for all molecular forms of the five chicken tissues studied.

A field lab method to determine urine concentration in small mammals

1. The concentrations of 136 urine samples from four species of small mammals were compared using osmometry, refractometry and a colorimetric test for urea concentration. 2. To obtain a wide range of concentrations (430-3950 mOsm/kg), urine samples were collected under normal and dehydration conditions. 3. Regression analyses of paired values indicate that measurements of total solids concentration (refractometric method) permit evaluations of urine osmolality and estimations of the concentration of urea with a high degree of confidence.

Generation process of cytosolic aspartate aminotransferase molecular forms by several treatments

Alpha-, beta-, and gamma-forms of chicken liver cytosolic aspartate aminotransferase generate variants on storage (4 degrees C, 25 days). The variants developed from each isolated form appeared as evenly spaced bands with increasing anodic mobilities after polyacrylamide gel electrophoresis (PAGE), pH 8.8, and specific staining. Their mobilities coincided with those of the more negatively charged forms present in fresh tissue. Development of faster-running variants on storage was avoided by addition of thiol reagents to the freshly isolated forms. In their presence, beta- and gamma-forms were partially transformed into one and two variants with lower anodic mobilities analogous to those of native alpha- and beta-forms. Short pH and heat treatments did not modify the electrophoretic patterns of the alpha-, beta-, and gamma-forms, but the incubation with 5 mM L-ascorbic acid (37 degrees C, 7 h) produced more anodic active bands. The formation of these variants was inhibited by the presence, in the incubation mixture, of superoxide dismutase and catalase. The kinetic parameters of the forms submitted to the different treatments were similar to those of the freshly isolated subforms. The results obtained suggest that minor subforms of the enzyme could be generated in vivo by a mechanism in which the oxidation of particular amino acid groups is involved.

Kinetic studies of chicken and turkey liver mitochondrial aspartate aminotransferase

The kinetic behaviour of chicken liver and turkey liver aspartate aminotransferases (L-aspartate:2-oxoglutarate aminotransferase, EC 2.6.1.1) was studied. Steady-state data were obtained from a wide range of concentrations of substrates and product L-glutamate. The data were fitted by rational functions of degree 1:1, 1:2 and 2:2 with respect to substrates and 0:1, 1:1, 0:2 and 1:2 with regard to product (L-glutamate), by using a non-linear regression program that guarantees the fit. The goodness of fit was improved by the use of a computer program that combines model discrimination parameter refinement and sequential experimental design. It was concluded that aspartate aminotransferase requires a minimum velocity equation of degree 2:2 for L-aspartate, 2:2 for 2-oxoglutarate and 1:2 for L-glutamate. Finally, a plausible kinetic mechanism that justifies these experimental results is proposed.

An improved purification method for cytosolic malate dehydrogenase from several sources

A new purification method for cytosolic malate dehydrogenases from several sources has been developed. The procedure, employing chromatographies on 5'AMP-Sepharose, DEAE-Sephacel and Blue-Sepharose, allows for a rapid isolation of the enzyme (approximately 40 hours), in large quantities, with good yields (45-54%). The specific activity of final preparations were around 1300 I.U./mg and were judged homogeneous by polyacrylamide gradient gel and sodium dodecyl sulfate polyacrylamide gel electrophoresis, high performance size exclusion chromatography and isoelectric focusing.

Purification of malate dehydrogenase from chicken liver mitochondria. Existence of a small quantity of cytosolic isoenzyme

1. A new purification method for chicken liver mitochondrial malate dehydrogenase is described. The application of affinity chromatography through 5'AMP-Sepharose and Blue-Sepharose permits to obtain homogeneous preparations, with good yields (47%), in a short time (48 hr). 2. The 5'AMP-Sepharose chromatography reveals the presence of two malate dehydrogenase species in the mitochondrial extracts. 3. A comparative study of these forms point out the cytosolic nature of the minority form and suggests that its presence could be due to a slight interaction of the cytosolic malate dehydrogenase with mitochondrial membranes.

Simultaneous purification and characterization of aspartate aminotransferase isoenzymes from chicken liver

Cytosolic and mitochondrial isoenzymes of aspartate aminotransferase (EC 2.6.1.1) were purified to homogeneity from chicken liver, without previous fractionation of the subcellular components. The procedure includes initial heat treatment and ammonium sulfate fractionation. The two isoenzymes can then be separated by a DEAE-Sepharose chromatography using a linear gradient of L-aspartate (reaction substrate). The separated fractions can be further purified by a parallel step with HA-Ultrogel prior to octyl-Sepharose (c-AAT) and CM-Sepharose (m-AAT) chromatographies. Michaelis constants, pI values, inhibition by adipate and subforms generation with time were studied for both isoenzymes.