Solution structure of the tetrameric minimum transforming domain of p53

We report the solution structure of the minimum transforming domain (residues 303-366) of human p53 (p53tet) determined by multidimensional NMR spectroscopy. This domain contains a number of important functions associated with p53 activity including transformation, oligomerization, nuclear localization and a phosphorylation site for p34/cdc2 kinase. p53tet forms a symmetric dimer of dimers that is significantly different from a recent structure reported for a shorter construct of this domain. Phosphorylation of Ser 315 has only minor structural consequences, as this region of the protein is unstructured. Modelling based on the p53tet structure suggests possible modes of interaction between adjacent domains in full-length p53 as well as modes of interaction with DNA.

Optical complex matrix-vector multiplication with negative binary inner products

Based on the mixed negative binary number system, we propose an inner-product algorithm for digital complex-valued matrix-vector multiplication. The features are no carries, no signs, no indications for decimal points, and simple preprocessing and postprocessing. Correspondingly, an optical architecture of incoherent optical correlation with spatial digital coding of data is suggested. Negative binary complex matrix-vector multiplication can be realized optically in parallel with a high accuracy. The experimental result is also given.

[Molecular cloning of alpha antigen like protein gene of Mycobacterium leprae and its over production in Escherichia coli]

I have constructed the genomic library of M. leprae Thai 53 strain, and cloned the alpha antigen like protein gene by plaque hybridization method by using M. leprae alpha antigen DNA fragment as probe which was characterized in the previous study, I have termed it as alpha 2 antigen gene. The alpha 2 antigen gene has been characterized by sequencing. By comparing the deduced amino acid sequence of alpha and alpha 2 antigen with 85 complex antigen of other mycobacteria. I have found the higher homology between alpha 2 antigen and 85A antigen and between alpha antigen and 85B antigen. We have constructed the over expression system of M. leprae alpha and alpha 2 antigen gene in E. coli using vector pMALc-RI. Recombinant alpha and alpha 2 antigen has been purified by amylose column chromatography at the purity of more than 95%. More than 6 mg and more than 10 mg of recombinant alpha and alpha 2 antigen has been obtained from 200 ml of liquid culture, respectively. ELISA tests have been performed with the sera of leprosy patient and healthy control against the recombinant alpha and alpha 2 antigens. The antibody titers in sera of leprosy patient against the two kinds of antigens were all much higher than healthy controls. The antibody titer against the alpha 2 antigen was higher than that against alpha antigen. Recombinant alpha and alpha 2 antigens in this study could be used as a new specific antigen for serodiagnosis of leprosy.

Antagonism between T3 and amiodarone on the contractility and the density of beta-adrenoceptors of chicken cardiac myocytes

3,3',5-Triiodothyronine (T3), at 10(-8) M, potentiated by 26.4-30.9% the isoproterenol-mediated inotropic effect in chick embryo cardiac myocytes in culture. Amiodarone (10(-6) M) decreased this response by 44.6% only in cells cultured with serum, where the T3 concentration was 10(-13) M. Amiodarone inhibited the potentiating effect of T3. Amiodarone alone had no influence on the beta-adrenoceptor density in cells cultured in serum-free medium. This confirms that the effects of amiodarone on cardiac beta-adrenoceptors are T3 dependent. T3 increased the density of beta-adrenoceptors through two concentration ranges, with an initial 30% increase between 10(-14) and 10(-11) M, followed by a second increase until 10(-7) M. Amiodarone not only inhibited the first positive effect of T3 but also decreased beta-adrenoceptor density far below the control value. The second positive T3 effect was also inhibited by 50% by amiodarone. This study suggests that T3 might increase the number of cell-surface beta-adrenoceptors and modify their cellular traffic through at least two mechanisms, one assumed to be non-genomic, the other being genomic, and that amiodarone could affect the two mechanisms differently.

Autoamputation of the fingertips in an 11-year-old boy

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. The final clinical and roentgenographic differential diagnoses can be found on the following pages.

A 47-year-old woman with a 5-year history of bilateral hand deformities

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. Initial history, physical findings, and roentgenographic examinations are offered for your consideration. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

An 11-year-old boy with swelling and progressive deformity of his finger

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. Initial history, physical findings, and roentgenographic examinations are found on the first two pages. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

Dual regulation of the glycogen phosphorylase 2 gene Dictyostelium discoideum: the effects of DIF-1, cAMP, NH3 and adenosine

Cell differentiation in Dictyostelium results in the formation of two cell types, stalk and spore cells. The stalk cells undergo programmed cell death, whereas spore cells retain viability. The current evidence suggests that stalk cell differentiation is induced by Differentiation Inducing Factor (DIF), while spore cell differentiation occurs in response to cAMP. We have discovered the first developmentally regulated Dictyostelium gene, the glycogen phosphorylase gene 2 (gp2) gene, that can be induced by both DIF-1 and cAMP, suggesting the possibility of a new group of developmentally regulated genes that have DIF-1 and cAMP dual responsiveness. The gp2 gene was found to be expressed in both prestalk/stalk cells and prespore/spore cells. The DIF-1 competence of the gp2 gene required uninterrupted development, whereas the cAMP-competence for the gene required only starvation. Both DIF-1 and cAMP induction of the gene could be inhibited by NH3, a factor that is thought to act as a developmental signal in Dictyostelium. Another developmental signal, adenosine, was found to repress the DIF-1 induction of the gp2 gene. Two introns in the gp2 gene were examined for their involvement in the regulation of the gene, but no regulatory function was detected. A model for the regulation of the gp2 gene during the development is proposed.

Disruption of glycogen phosphorylase gene expression in Dictyostelium: evidence for altered glycogen metabolism and developmental coregulation of the gene products

Glycogen phosphorylase 1 and 2, the isozymes responsible for glycogen degradation, are encoded by separate genes in Dictyostelium. The two gene products display different transcriptional and translational expression and distinct post-translational regulation. Using DNA-mediated transformation, Dictyostelium clones which lacked either glycogen phosphorylase 1 or 2 (gp1 or gp2) expression were obtained. The loss of either enzyme did not change axenic growth patterns, developmental progression, or gross organismic morphology. In gp1- strains, glycogen accumulated to a 17- to 28-fold higher level during late stationary phase without any obvious detrimental effects. This implies that no alternative pathway for glycogen degradation is present in amoebae, and that glycogen metabolism is not critical for vegetative cell growth. Developmental glycogen concentrations were not altered significantly in any of the transformants, but in gp2- cells the posttranslational regulation of the intact gp1 enzyme was apparently modulated to compensate for the loss of gp2. Western blots of microdissected, lyophilized Dictyostelium slugs and early culminates showed that gp2 was found in both prestalk and prespore cells, with a slight enrichment in prespore cells. The gp1 protein was highly enriched in prestalk cells in the parental strain. In gp2- transformants, however, gp1 was detected in equal amounts in both cell types. The loss of gp2 led to a shift in the cell-type-specific expression pattern of gp1, presumably due to developmental coordinate regulation of gp1 and gp2 at the translational and/or transcriptional level.

A 30-year-old woman with 13-year history of pain in multiple joints

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. Initial history, physical findings, and roentgenographic examinations are found on the first two pages. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

A 73-year-old woman with stiffness in both hands

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. Initial history, physical findings, and roentgenographic examinations are found on the first page. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

Endemic fluorosis of the skeleton: radiographic features in 127 patients

OBJECTIVE

A wide range of radiographic appearances have been reported in skeletal fluorosis, but little has been written about the spectrum of radiographic features. We evaluated the spectrum of radiographic appearances in this disorder to help with its diagnosis and differentiation from other metabolic skeletal disorders.

MATERIALS AND METHODS

One hundred twenty-seven patients with clinically proved endemic fluorosis had radiographs of the chest, spine, pelvis, elbow, forearm, and knee obtained. The radiographic findings were classified as osteosclerosis, osteopenia, intermittent growth lines, diaphyseal widening, or soft-tissue ossification. Two different osteopenic patterns were defined: an osteoporotic pattern with overall decreased bone density and an osteomalacic pattern that combines the features of osteoporosis with bone deformity. Soft-tissue ossification included involvement of ligaments, tendons, and interosseous membranes.

RESULTS

Ninety-eight of the patients (89% of the adults) had some evidence of calcification and/or ossification of the attachments of ligaments, tendons, muscles, and interosseous membranes. Osteosclerosis was seen in 54 patients (43%), and osteopenia was seen in 51 patients (40%). Of the patients with osteopenia, the osteoporotic pattern was seen in 28 and the osteomalacic pattern in 23. Growth lines were found in 89 patients (70%). Metaphyseal osteomalacic zones were found in children. Diaphyseal widening was present in 35 patients (28%).

CONCLUSION

Endemic skeletal fluorosis can have a wide variety of radiographic appearances, including calcification and/or ossification of the attachments of soft-tissue structures to bone, osteosclerosis, osteopenia, growth lines, and metaphyseal osteomalacic zones.

Developmental and cAMP-mediated regulation of glycogen phosphorylase 1 in Dictyostelium discoideum

The Dictyostelium discoideum glycogen phosphorylase-1 (gp-1) exhibits a complex pattern of developmental expression in which differential temporal regulation of enzyme activity, protein levels and mRNA levels is observed. This pattern of expression implies that gp-1 regulation occurs at multiple levels, probably involving both transcriptional and post-transcriptional events. Post-translational control of gp-1 activity, in effect, actually regulates the protein from a developmental perspective. In this report we have examined several facets of this regulation. We show that addition of exogenous cAMP to cells in suspension culture caused changes in gp-1 enzyme activity and mRNA levels that are identical to those observed during normal development, suggesting that cAMP is involved in the regulation of gp-1. Exogenous cAMP could regulate gp-1 mRNA expression at concentrations as low as 1.0 microM. cAMP regulation of gp-1 mRNA appeared to occur through a mechanism that required intracellular cAMP signalling. We identified regions of the promoter necessary for gp-1 expression by using gp-1 promoter deletions to drive the expression of a luciferase reporter gene. Results of these experiments suggested that developmental and cAMP-mediated changes in gp-1 mRNA levels were the result of alterations in transcription. The promoter analysis also suggested that a vegetative specific element is located between -785 and -1894 nucleotides from the transcriptional start site. Elements necessary for maximal developmental and cAMP-mediated expression appear to be located between -1153 and -1894 nucleotides from the cap site. Sequence elements located between -180 and -1153 appear to be required for a basal level of late developmental expression.

Diet, aberrant crypt foci and colorectal cancer

We have used the aberrant crypt focus (ACF) assay to test and develop hypotheses linking diet and colon cancer. The hypotheses were suggested by epidemiological studies that identified possible dietary factors associated with colorectal cancer risk. The ACF assay was used to quantitate the effect of the dietary factors on the initiation and growth of these putative precursors of colon cancers in experimental animals. Using this approach we have developed 3 new hypotheses for the role of diet in colorectal cancer. These are (1) a risk associated with 5-hydroxymethyl-2-furaldehyde in caramelized sugar, (2) a risk associated with some factor in thermolyzed casein, and (3) a risk associated with single nutrient boluses of sucrose and fructose. The importance of these hypotheses has still to be tested in long term carcinogenesis experiments, in analytic epidemiology studies and then, perhaps, in intervention trials.

A 21-year-old man with pain and swelling of the right hand

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. Initial history, physical findings, and roentgenographic examinations are found on this page. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

A 43-year-old woman with right hip pain

Although tuberculous arthritis is currently uncommon in the United States, the hip joint is a common location. Tuberculous arthritis usually presents as a mild, slowly progressing process. It often involves a single joint. Radiological findings include osteopenia of the involved joint, soft tissue swelling, bone destruction without evidence of bone formation, and sequestrum formation. Several conditions should be considered in the differential diagnosis. The detailed roentgenographic appearances and many of the differential diagnoses are included in this paper. Final diagnosis is made by positive culture results or finding the bacillus histologically.

Identification of a carbohydrate recognition domain in filamentous hemagglutinin from Bordetella pertussis

The adherence of Bordetella pertussis to ciliated cells and macrophages is critical to colonization and infection of the respiratory tract. Adherence to both types of cells involves the recognition of eukaryotic carbohydrates by the bacterial adhesin filamentous hemagglutinin (Fha). The carbohydrate recognition domain (CRD) of Fha is considered an important antigen for subcomponent vaccines to maximize the generation of antiadherence antibodies capable of protecting against colonization. For identification of the CRD of Fha, a bank of eight monoclonal antibodies (MAbs) that mapped to four contiguous regions were tested for their ability to block Fha binding to lactosylceramide or to block bacterial binding to ciliated cells. Only MAb 12.5A9, which maps to amino acid residues 1141 to 1279, blocked both Fha binding to lactosylceramide and bacterial binding to ciliated cells. An 18-kDa polypeptide corresponding to this region was expressed in Escherichia coli. Cell lysates containing this protein bound to lactosylceramide in a manner identical to that of native Fha. Mutant strains of B. pertussis that contained an in-frame deletion of the coding sequence for this region produced a truncated Fha that showed negligible cross-reactivity with MAb 12.5A9. In an adherence assay, these mutant strains failed to bind efficiently to either ciliated cells or macrophages. The numbers of adherent bacteria for these strains were reduced to the number obtained with a nonadherent strain. We conclude that the region defined by residues 1141 to 1279 of Fha constitutes a CRD critical for bacterial adherence and represents a potential candidate for a subcomponent vaccine.

A 77-year-old man with a gradually enlarging mass of the left ring finger

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. Initial history, physical findings, and roentgenographic examinations are found on the first page. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

Conformational changes at the active site of creatine kinase at low concentrations of guanidinium chloride

It has been previously reported that, during denaturation of creatine kinase by guanidinium chloride (GdmCl) or urea [Tsou (1986), Trends Biochem. Sci. 11, 427-429], inactivation occurs before noticeable conformational change can be detected, and it is suggested that the conformation at the active site is more easily perturbed and hence more flexible than the molecule as a whole. In this study, the thiol and amino groups at or near the active site of creatine kinase are labelled with o-phthalaldehyde to form a fluorescent probe. Both the emission intensity and anisotropy decrease during denaturation indicating exposure of this probe and increased mobility of the active site. The above conformational changes take place together with enzyme inactivation at lower GdmCl concentrations than required to bring about intrinsic fluorescence changes of the enzyme. At the same GdmCl concentration, the rate of exposure of the probe is comparable with that of inactivation and is several orders of magnitude faster than that for the unfolding of the molecule as a whole.

A 35-year-old-man with pain in the metatarsophalangeal joints. Soft-tissue chondroma

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. Initial history, physical findings, and roentgenographic examinations are found on the first two pages. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

Cloning and sequencing of a cDNA coding for bovine conglutinin

A 912 bp bovine cDNA fragment encoding bovine conglutinin was amplified by the RT-PCR technique. cDNA clones encoding the bovine conglutinin were isolated from a bovine liver cDNA library using a specific probe obtained from the PCR product. These cDNAs carry an insert of 1113 bp coding for a protein of 371 amino acid residues with a signal peptide of 20 residues. The deduced amino acid sequence of cDNA agrees with that determined by conventional amino acid sequence analysis. Two polyadenylation signal sequences were detected in the DNA sequence downstream of the 3' end of the gene. Southern blot analysis of total bovine genomic DNA indicated that there is only one copy of the gene encoding bovine conglutinin. Northern blot analysis of bovine tissues showed that conglutinin mRNA of about 1.5 kb is expressed in the liver and also slightly in the lung.

A 67-year-old woman with pain and tenderness in the left long finger

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. Initial history, physical findings, and roentgenographic examinations are presented along with the final histologic and differential diagnoses.

A 2-year-old girl with painful right ankle

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. The initial history, physical findings, and roentgenographic examinations are found on this page. The final clinical and roentgenographic differential diagnosis is then presented.

DNA repair in congenic mice: possible influence of a chromosome 4 genetic region on the rate of benzo[a]pyrene-induced DNA adduct removal

An attempt was made to assign mouse lifespan-associated interstrain differences in DNA repair to a specific chromosomal region using a set of congenic mice. The sensitive 32P-postlabeling assay was employed to measure the removal of benzo[a]pyrene-induced DNA adducts in liver DNA of three different chromosome 4 congenic mouse strains: B6.C-H-15c, B6.C-H-16c, and B6.C-H-26c and the two parental strains, C57B1/6 and BALB/c. The removal of the one main adduct detected, trans-(7R)-N2-[10-(7 beta,8 alpha,9 alpha-trihydroxy)-7,8,9,10- tetrahydrobenzo(a)-pyrene]-yl-deoxyguanosine (BPDE-N2-dG), in liver DNA of C57Bl/6 and BALB/c mice between one and three days after treatment, was approximately 86% and 57%, respectively. The percentage removal of BPDE-N2-dG in two of the three congenic mouse strains, B6.C-H-16c and B6.C-H-26c, resembled that found in BALB/c, whereas the third strain, B6.C-H-15c, removed about the same amount as C57B1/6, i.e., approximately 88% of BPDE-N2-dG between one and three days after treatment. The usefulness of congenic mouse strains for identifying genes putatively involved in aging and/or disease susceptibility is discussed.

A 35-year-old man with right wrist pain

The following is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. The initial history, physical findings, and roentgenographic examinations are found on this page. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

Wild-type p53 restores cell cycle control and inhibits gene amplification in cells with mutant p53 alleles

Loss of cell cycle control and acquisition of chromosomal rearrangements such as gene amplification often occur during tumor progression, suggesting that they may be correlated. We show here that the wild-type p53 allele is lost when fibroblasts from patients with the Li-Fraumeni syndrome (LFS) are passaged in vitro. Normal and LFS cells containing wild-type p53 arrested in G1 when challenged with the uridine biosynthesis inhibitor PALA and did not undergo PALA-selected gene amplification. The converse occurred in cells lacking wild-type p53 expression. Expression of wild-type p53 in transformants of immortal and tumor cells containing mutant p53 alleles restored G1 control and reduced the frequency of gene amplification to undetectable levels. These studies reveal that p53 contributes to a metabolically regulated G1 check-point, and they provide a model for understanding how abnormal cell cycle progression leads to the genetic rearrangements involved in tumor progression.

Dictyostelium giganteum plasmid Dgp1 is a member of the Ddp2 plasmid family

Dgp1, a circular 4.4-kb plasmid found in the nuclei of Dictyostelium giganteum strain DG61, is a member of the same plasmid family as plasmids Ddp2 and pDG1. Dgp1 has sequence similarity to a conserved region of the Ddp2 and pDG1 open reading frames. As with Ddp2 and pDG1, a single large RNA is transcribed from Dgp1. This 3.3-kb transcript is present at about 350 copies per vegetative cell. The transcript abundance decreased about 10-fold in early aggregation and continued at this lower level until late culmination when it returned to the level seen in vegetative cells. Dgp1 has a repeat of several hundred base pairs in a location, relative to the transcribed region, similar to the inverted repeats found in Ddp2 and pDG1. Dgp1 cannot be maintained as a plasmid in Dictyostelium discoideum AX4 cells, suggesting that Dgp1 carries species-specific maintenance elements.

Inhibition by germanium oxide of the mutagenicity of cadmium chloride in various genotoxicity assays

The effects of germanium oxide on the genotoxicity of cadmium chloride were investigated. The incorporation of [3H]thymidine into testicular DNA was inhibited in mice injected ip with 1.35, 1.80 or 2.70 mg cadmium chloride/kg body weight. Germanium oxide (0.05 or 0.1 mg/kg body weight, sc) alone did not affect [3H]thymidine incorporation into testicular DNA but 0.05 mg germanium oxide/kg antagonized the inhibitory effect of 1.35 mg cadmium chloride/kg. However, combinations of the other doses of the two compounds did not show statistically significant antagonistic effects. Cadmium chloride significantly increased the frequencies of micronucleus formation in polychromatic erythrocytes, and of chromosome aberrations in the bone marrow of mice treated with 0.7, 1.4 or 2.7 mg/kg body weight, in a dose-related manner. These effects were inhibited by germanium oxide at doses of 0.1 or 0.5 mg/kg body weight, although germanium oxide alone did not affect micronucleus formation or the chromosome aberration rate. Cadmium chloride produced a dose-related increase in the frequency of sister chromatid exchanges in cultured human lymphocytes at concentrations of 5, 10 or 50 mumol. This effect was also inhibited by germanium oxide (0.05 or 0.1 mumol), although germanium oxide alone had no effect. There was a dose-related increase in the frequency of sperms with abnormal head morphologies from mice treated with 0.6, 1.1 or 2.2 mg cadmium chloride/kg body weight and this too was antagonized by the injection of germanium oxide (0.1 or 0.5 mg/kg body weight). Germanium oxide alone did not affect the frequency of sperm-head abnormalities.

Vinyl ether hydrolysis. XXIV. 1-Methoxycyclooctene and the question of reversibility of the carbon protonation step

An argument is presented which suggests that hydrolysis of the vinyl ether group of 1-methoxycyclooctene may occur by reversible proton transfer from a catalyzing acid to the β-carbon atom of the substrate, instead of by the conventional reaction mechanism in which this proton transfer is rate determining and not reversible. Hydrolysis of this substrate is then examined by measuring rates of reaction in dilute aqueous solutions of strong mineral acids (perchloric and hydrochloric) as well as in buffer solutions of seven carboxylic acids, biphosphate ion, and 1,1,1,3,3,3-hexafluoro-2-propanol. General acid catalysis is observed and a Brønsted relation with the exponent α = 0.73 is constructed. That, plus the isotope effects kH/kD = 2.9 and 6.0 for catalysis by hydronium ion and acetic acid respectively, as well as the lack of deuterium incorporation into the substrate when the reaction is carried out in D2O with D2PO4−/DPO42− buffer at pD = 8, show that carbon protonation of the substrate is not reversible and that the conventional reaction mechanism is operative. Key words: 1-methoxycyclooctene, vinyl ether hydrolysis, rate-determining proton transfer, Brønsted relation, solvent isotope effect.

[Field potentials evoked by stimulation of DLF in the rat spinal cord]

When stimulation of DLF at cervical cord, a train of evoked potentials are recorded with a microelectrode at lumber level in rat. The longer slow positive potential wave, latency 7.22 +/- 1.41 ms, peak time 15 +/ 12 +/- 5.58 ms, duration 93 +/ 92 +/- 9.06 ms, is called DLF-FP. The negative center of the isopotential map of DLF-FP is located at 1.0-1.3 mm below the dorsal surface nearly in coincidence with that of the P1-FP evoked by the sural nerve stimulation. The amplitude of DLF-FP was decreased by picrotoxin and increased by strychnine. Both summation and inhibition can be observed between the potentials evoked by stimulation of the sural nerve and DLF. The results mentioned above show that DLF-FP is the reflection of primary afferent depolarization probably by the same spinal circuit underlying P1-FP.

[A report of investigations on an outbreak of type B paretyphoid fever]

A disease with main symptoms of fever, headache, malaise, profuse sweating and diarrhoea occurred as an outbreak in a few villages at suburb of Hengyang City from March to July 1987. It was diagnosed as Type B paratyphoid fever by laboratory examinations. The number of cases occurred in this outbreak was 59 in total. All of them recovered after isolation and proper-treatment.

Exposure level monitor of a carcinogenic glutamic acid pyrolysis product in rabbits

In order to determine a suitable indicator for estimating the exposure levels of the dietary carcinogen 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), a carcinogenic glutamic acid pyrolysis product, the levels of Glu-P-1 bound to blood components were monitored for 8 weeks by a high-performance liquid chromatography method after the dietary carcinogen was administered as single oral doses (0.2-50 mg) to rabbits. In all rabbits dosed with Glu-P-1, Glu-P-1 in erythrocytes was detectable even on day 42 after administration. Glu-P-1 in plasma disappeared faster than did Glu-P-1 in erythrocytes. Glu-P-1 levels in rabbit hemoglobin were linearly related to administered doses at all points of time investigated. The results suggest that Glu-P-1 covalently bound to hemoglobin is very suitable for monitoring long-term exposure levels.

Risk of stroke in male cigarette smokers

From 1965 to 1968, the Honolulu Heart Program began following 8006 men of Japanese ancestry in a prospective study of cardiovascular disease. Of the subjects who had not had a stroke by the time of study entry, 3435 were cigarette smokers and 4437 were nonsmokers. In 12 years of follow-up, 171 smokers and 117 nonsmokers had a stroke. As compared with nonsmokers, cigarette smokers had two to three times the risk of thromboembolic or hemorrhagic stroke, after control for age, diastolic blood pressure, coronary heart disease, and other risk factors (P less than 0.001). Subjects who continued to smoke in the course of follow-up had the highest risk of stroke. When these subjects were compared with those who never smoked, their risk of hemorrhagic events was increased four- to six-fold (P less than 0.001). Subjects who were smokers at study entry but stopped smoking in the course of follow-up had a slight excess risk of stroke. When these subjects were compared with those who continued to smoke, however, their risk was reduced by more than half after adjustment for risk factors (P less than 0.05), indicating that stopping smoking had significant benefits.

BCG test reaction in previously BCG vaccinated children

BCG test reactions were studied in 1095 non-tuberculous children from 6 months to 5 years of age, who had received BCG vaccination in the newborn period, in order to find out the diagnostic value of the BCG test in previously BCG vaccinated children. Previous BCG vaccination has an effect on the BCG test reaction in the form of an accelerated BCG reaction. Although the degree of reaction decreases with time, 51.4% of children still showed a strongly accelerated BCG reaction 4 1/2-5 years after BCG vaccination. It is concluded that the BCG test cannot be used as a diagnostic test for tuberculosis in children under 5 years of age who have had previous BCG vaccination.