Expression of p16 and p21 in the frontal association cortex of ALS/MND brains suggests neuronal cell cycle dysregulation and astrocyte senescence in early stages of the disease.

AIMS: Cellular senescence plays a role in organismal ageing and has been linked to persistent DNA damage in age-related diseases. Brain senescence has been described in astrocytes and microglia, but it is less well understood in neurones. Evidence suggests that neurones activate a senescence-like mechanism that could contribute to neurodegeneration. We aimed to determine whether a persistent DNA damage response (DDR) and senescence activation are features of motor neurone disease (amyotrophic lateral sclerosis, ALS/MND). METHODS: We examined expression of senescence (p16 and p21) and DNA damage markers (8-OHdG and γH2AX) in motor cortex (MCx), frontal association cortex (FACx) and occipital cortex (OCx) in post-mortem tissue donated by patients with ALS/MND and controls. RESULTS: Nuclear expression of p16 and p21 was detected in glial cells; double immunofluorescence for p16/p21 and glial fibrillary acidic protein (GFAP) suggested that some of these cells were GFAP+ astrocytes. p21 nuclear expression was also found in neurones. Higher levels of p16+ (glia, P = 0.028) and p21+ (glia, P = 0.003; neurones, P = 0.008) cells were found in the FACx of ALS/MND donors but not in the MCx or OCx. Expression of p16 and p21 did not correlate with 8-OHdG or γH2AX. CONCLUSIONS: Expression of p16 and p21 in glia, mainly in astrocytes, suggests senescence induction in these cells; however, neuronal p21 expression might reflect a more general mechanism of age-related cell cycle dysregulation. The significantly higher proportion of cells expressing either p16 or p21 in the FACx of ALS/MND donors could indicate senescence activation and cell cycle dysregulation in early stages of the disease.

Presence of calcium antagonist activity explains the use of Syzygium samarangense in diarrhoea.

Syzygium samarangense (Family; Myrtaceae) or 'makopa', as it is commonly known, is native to Malaysia, some islands of Indonesia and to Far East in general. This study was undertaken to rationalize the use of this plant in hypermotility states of the gut. The hexane extract of S. samarangense (Ss.Hex) was found to dose-dependently (10-3000 microg/mL) relax the spontaneously contracting isolated rabbit jejunum. When tested for a possible calcium channel blocking (CCB) activity, the extract (10-1000 microg/mL) relaxed the high K+-induced contractions and also decreased the Ca++ dose-response curves in a dose-dependent manner (30-100 microg/mL), confirming the CCB activity. Four flavonoids isolated from the hexane extract were tested for a possible spasmolytic activity. All flavonoids, identified as: 2'-hydroxy-4',6'-dimethoxy-3'-methylchalcone (SS1), 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (SS2), 2',4'-dihydroxy-6'-methoxy-3'-methylchalcone (SS3) and 7-hydroxy-5-methoxy-6,8-dimethylflavanone (SS4), showed dose-dependent (10-1000 microg/mL) spasmolytic activity with SS2 being the most potent. These results indicate that the presence of compounds with spasmolytic and calcium antagonist activity may be responsible for the medicinal use of the plant in diarrhoea.

Differences between coding and non-coding regions in the Trichomonas vaginalis genome: an actin gene as a locus model(1).

The sequence of a cloned genomic fragment of Trichomonas vaginalis containing a complete actin gene was determined. An uninterrupted open reading frame of 1128 nucleotides was found that codes for an actin gene. Two overlapped consensus promoter sequences for T. vaginalis were found 12 nucleotides upstream the actin initiation codon. In addition to actin, two incomplete open reading frames were found at the 5' and 3' ends of the clone. These two sequences are expressed and showed similarity to adenylate cyclase genes and a yeast hypothetical protein. The overall sequence showed a higher G+C content and a lower frequency of repeated sequences in the coding regions when compared with the non-coding regions. A similar unequal nucleotide distribution was found in various T. vaginalis genes retrieved from data bases.

Anticarcinogenicity potential of spinasterol isolated from squash flowers.

Spinasterol, an antimutagen, was isolated from squash flowers by solvent partitioning and repeated vacuum liquid chromatography. Spinasterol was then tested for its anticarcinogenic potential by using the mouse skin tumor assay. There was a 90% skin tumor incidence for the positive control group (DMBA + croton oil + acetone). At a concentration of 15.0 microg/0.2 ml acetone, spinasterol decreased the incidence of skin tumors by 55.6% and decreased the number of tumors by 65.0% when applied immediately after croton oil. Hence, spinasterol showed antitumorigenic potential. It is not a co-carcinogen nor a co-tumor promoter as there was no increase in the incidence of skin tumors after spinasterol application. Teratogenesis Carcinog. Mutagen. 20:99-105, 2000.

Antigenotoxic spinasterol from Cucurbita maxima flowers.

The antigenotoxic constituent of squash flowers was isolated by solvent partitioning and repeated vacuum liquid chromatography. The micronucleus test, an in vivo method, was used to monitor the antigenotoxicity of the various fractions during the isolation process. Isolate SQFwB2D from the chloroform extract of squash flowers is the most antigenotoxic isolate. It decreased the mutagenicity of tetracycline by 64.7% at a dosage of 100 mg/kg mouse. Statistical analysis using Kruskall Wallis one-way analysis of variance by Ranks showed that SQFw2D is different from the control group (tetracycline + corn oil) at alpha = 0.001. GC-MSD of isolate SQFwB2D shows 2 peaks at Rt = 19.860 (SQFwB2D-1) and 20.242 min (SQFwB2D-2) with relative peak heights of 16:1, respectively. Spectral analyses show that SQFwB2D-1 is 24 alpha-ethyl-5 alpha-cholesta-7,trans-22-dien-3 beta-ol or spinasterol.

Clastogenicity of red pepper (Capsicum frutescens L.) extracts.

Extracts from the fruits of Capsicum frutescens L. were tested for their clastogenicity using the mouse-bone-marrow micronucleus (mouse-MN) assay. Results of the mouse-MN, an in vivo method, indicated that the isolate CF-1 is clastogenic at the maximum tolerated dose of 1.22 mg/kg mouse. Statistical analysis using the Wilcoxon two-sample test showed that the null hypothesis, mu tetracycline = muCF-1, is acceptable at 0.05 and 0.01 degrees of significance. Hence, the clastogenicity of CF-1 is statistically similar to that of tetracycline, a known clastogen, at the 5% and 1% levels of significance.

Structure of an antimutagen from Carmona retusa leaves.

An antimutagenic compound was isolated from the leaves of Carmona retusa (Vahl) Masam. Its structure has been elucidated by spectral analysis to be 4-hydroxy-7,8,11,12,15,7',8',11',12',15'-decahydro-beta, psi-carotene. The results of the Micronucleus Test, an in vivo method, showed that the isolated antimutagenic compound reduced by approximately 68.4% the number of micronucleated polychromatic erythrocytes induced by tetracycline, a known mutagen.

Antimutagen from leaves of Carmona retusa (Vahl) Masam.

An antimutagenic principle was extracted from the leaves of Carmona retusa with ethyl alcohol. This was then purified by solvent partition and liquid chromatography. The micronucleus test, an in vivo method, using albino mice as the test system was used for monitoring the antimutagenic activity. At a dosage of 23.4 mg/kg body weight, the pure isolate reduced by 68.4% the number of micronucleated polychromatic erythrocytes induced by the mutagen tetracycline. Statistical analysis (one-way ANOVA) shows that the variance of the pure isolate differs significantly from that of tetracycline, a known mutagen.

Transfer, expression, and inheritance of salmonid growth hormone genes in channel catfish, Ictalurus punctatus, and effects on performance traits.

We examined expression and inheritance of salmonid growth hormone genes RSVLTR-rtGH1 cDNA and RSVLTR-csGH cDNA, transferred to channel catfish (Ictalurus punctatus) by microinjection. One to 9 copies of the foreign DNA were inserted in either head-to-tail tandem array at single insertion sites or single copies at multiple insertion sites. All P1 transgenic catfish evaluated produced salmonid growth hormone regardless of the construct. Five P1 x P1 matings were accomplished. The spawning rate and fertility of these P1 transgenics in artificial spawning conditions were comparable to those of normal channel catfish. In two of three years, 100% spawning and 100% hatch were obtained. Percent transgenic progeny observed in the five matings were 20, 52, 7, 47, and 0%, which was lower (P < 0.001, chi 2) than the 75% inheritance expected assuming the P1 brood stock had at least one copy of the foreign gene integrated and were not mosaics in the germ line. At least 7 of 10 P1 were mosaics, and a minimum of 2 of 10 P1 did not possess the salmonid growth hormone genes in their germ line. P1 transgenics grew at the same rate as their nontransgenic full siblings, which is not surprising because the P1 were mosaics. F1 transgenic progeny in two families possessing RSVLTR-csGH cDNA grew 26% faster, to 40 to 50 gm, than their nontransgenic full siblings when evaluated communally. One F1 progeny group produced by RSVLTR-rtGH1 cDNA x RSVLTR-csGH cDNA mating and one F1 progeny group (parents either RSVLTR-rtGH1 cDNA or RSVLTR-csGH cDNA) grew at the same rate as normal full siblings when grown communally to 25 gm and 60 mg, respectively. In families where F1 progeny grew faster than controls, the range in body weight and coefficient of variation for the transgenic full siblings were less than those for controls. In families where F1 progeny grew at the same rate as controls, range in body weight and coefficient of variation were similar for transgenic and normal individuals. The percent deformities observed in P1 transgenics (13.6%) was higher (P < 0.05) than in microinjected P1 nontransgenics (5.1%). Percent deformities in transgenics and control F1 channel catfish was not different (p > 0.05; 0.5 and 2.8%, respectively).

Mutagens from roasted seeds of Moringa oleifera.

A number of biosynthetically and chemically related compounds were isolated from the roasted seeds of Moringa oleifera. The micronucleus test, an in vivo method, using albino mice as the test system, was used for monitoring the mutagenicity of the isolated compounds. Structure-activity correlation studies showed that 4(alpha-L-rhamnosyloxy)phenylacetonitrile, 4-hydroxyphenylacetontrile, and 4-hydroxyphenyl-acetamide exhibited mutagenic activity.

Structure of a mutagen from roasted seeds of Moringa oleifera.

A mutagenic compound was isolated from roasted seeds of Moringa oleifera Lam. Its structure has been elucidated by spectral analysis as 4(alpha-L-rhamnosyloxy)phenylacetonitrile. The results of the Micronucleus Test, an in vivo method, showed that the number of micronucleated polychromatic erythrocytes (PCE)/1000 PCE for this compound is higher than that of the solvent control, dimethylsulfoxide, and approximates that of the positive control, tetracycline. This indicates that 4(alpha-L-rhamnosyloxy)phenylacetonitrile is a genotoxic compound.

[Program for instruction in comprehensive general medicine: conceptualization and strategies for its evaluation]. / Programa de enseñanza de medicina general integral: conceptualización y estrategias para su evaluación.

This article describes the concepts and strategies underlying the evaluation of the Comprehensive General Medicine Program of the School of Medicine of the Autonomous National University of Mexico. The exact purpose of that evaluation, done in 1982, was to strengthen and redirect the lines of this program's current development, which had been conceived since its inception in 1974 as an experimental study plan based on a system of modular and tutorial instruction. The article describes the identified conceptual, methodological, logistic, operational and attitudinal obstacles to this evaluation process. The methodology involves a sequence consisting in the evaluational experiences of basically innovative programs of undergraduate medical instruction, the selection of an evaluation model, identification of the aspects to be evaluated, the determination of priorities, and the definition of specific evaluation projects. From the aspects identified and given priority the following 12 evaluation projects emerged: curriculum review, follow-up of alumni, instruction materials, tutors, integration of knowledge, student performance, instructional activities, students in social service, student enrollments, dropping out, professional examination, and education administration.

Programa de enseñanza de medicina general integral: conceptualización y estrategias para su evaluación / Program for instruction in comprehensive general medicine: conceptualization and strategies for its evaluation

This article describes the concepts and strategies underlying the evaluation of the Comprehensive General Medicine Program of the School of Medicine of the Autonomous National University of Mexico. The exact purpose of that evaluation, done in 1982, was to strengthen and redirect the lines of this program's current development, which had been conceived since its inception in 1974 as an experimental study plan based on a system of modular and tutorial instruction. The article describes the identified conceptual, methodological, logistic, operational and attitudinal obstacles to this evaluation process. The methodology involves a sequence consisting in the evaluational experiences of basically innovative programs of undergraduate medical instruction, the selection of an evaluation model, identification of the aspects to be evaluated, the determination of priorities, and the definition of specific evaluation projects. From the aspects identified and given priority the following 12 evaluation projects emerged: curriculum review, follow-up of alumni, instruction materials, tutors, integration of knowledge, student performance, instructional activities, students in social service, student enrollments, dropping out, professional examination, and education administration (Au)