Phosphorylation-dephosphorylation of pyruvate dehydrogenase from bakers' yeast

The pyruvate dehydrogenase complex was purified to homogeneity from bakers' yeast (Saccharomyces cerevisiae). No pyruvate dehydrogenase kinase activity was detected at any stage of the purification. However, the purified pyruvate dehydrogenase complex was phosphorylated and inactivated with purified pyruvate dehydrogenase kinase from bovine kidney. The protein-bound radioactivity was localized in the pyruvate dehydrogenase alpha subunit. The phosphorylated, inactive pyruvate dehydrogenase complex was dephosphorylated and reactivated with purified pyruvate dehydrogenase phosphatase from bovine heart. Tryptic digestion of the 32P-labeled complex yielded a single phosphopeptide, which was purified to homogeneity. The sequence of the phosphopeptide was established to be Tyr-Gly-Gly-His-Ser(P)-Met-Ser-Asp-Pro-Gly-Thr-Thr-Tyr-Arg. This sequence is very similar to the sequence of a tryptic phosphotetradecapeptide derived from the alpha subunit of bovine kidney and heart pyruvate dehydrogenase: Tyr-His-Gly-His-Ser(P)-Met-Ser-Asp-Pro-Gly-Val-Ser-Tyr-Arg.

Appearance and persistence of hepatitis A IgM antibody in acute clinical hepatitis A observed in an outbreak

143 patients with acute hepatitis A observed during a common source outbreak were tested for IgM class antibody to hepatitis A virus (IgM anti-HAV) by commercially available solid phase radioimmunoassays. All patients were IgM anti-HAV positive though six of them were initially negative when tested within three days after the onset of symptoms. The levels of IgM anti-HAV peaked two to four weeks after onset, and declined gradually thereafter. The probability of IgM anti-HAV positivity was 25% at the end of the sixth month, and 3.4% at the end of the ninth month after onset. No significant sex or age difference in the persistence of IgM anti-HAV was observed. It was suggested that the timing of the assay and the level of IgM anti-HAV should be considered in the etiological diagnosis of acute hepatitis.

Neuropeptide-like immunoreactive cells in the retina of the larval tiger salamander: attention to the symmetry of dendritic projections

Light microscopic immunocytochemistry was used to study the morphology of cells that showed immunoreactivity (IR) to antisera against substance P (SP), glucagon (GLU), met enkephalin (ENK), and somatostatin (SS) in the retina of the larval tiger salamander. Both vertical sections and retinal whole mounts were studied. All four antisera labeled amacrine cells in the inner nuclear layer and cells in the ganglion cell layer (GCL). GLU-IR cells had processes stratified throughout the inner plexiform layer (IPL), whereas the other three types had bistratified projections in laminae 1 and 5, with lamina 5 being broader and more dense. Two types of SS-IR amacrine cell were observed. As seen in retinal whole mount, most GLU-IR and ENK-IR amacrine cells had processes that were symmetrically distributed about the soma, whereas processes of SS- and SP-IR amacrine cells were markedly asymmetrical. The dendritic fields of SP-IR amacrine cells were selectively oriented toward the periphery of the retina in the nasal, temporal, and dorsal areas. Immunoreactive cells in the GCL had fine projections into the IPL and in addition gave rise to two large oriented processes proximal to the soma that projected in opposite directions for 100-200 microns. The oriented processes often showed further branching; they appeared to be along the radiated lines from the optic disc but did not enter it. The implications of the selectively oriented processes of SP-IR amacrine cells and cells in the GCL are discussed.

Molecular cloning and expression of partial cDNAs and deduced amino acid sequence of a carboxyl-terminal fragment of human apolipoprotein B-100

Apolipoprotein (apo) B-100 cDNAs were identified in a human liver cDNA library cloned in the expression vector lambda gt11. The beta-galactosidase-apoB-100 fusion protein was detected by two independently produced low density lipoprotein polyclonal antisera and by three apoB-100 monoclonal antibodies that crossreact with apoB-74. It was not recognized by two apoB-100 monoclonal antibodies that crossreact with apoB-26. The longest clone, lambda B8, was completely sequenced. It contains a 2.8-kilobase DNA fragment containing the codons for the carboxyl-terminal 836 amino acid residues of apo-B-100, as well as the 3' untranslated region of apoB-100 mRNA. We have thus mapped apoB-74 to the carboxyl-terminal portion of apoB-100. The deduced amino acid sequence of the cloned DNA matches the sequences of 14 apoB-100 peptides determined in our laboratory. Minor differences in amino acid sequence were noted in three of the peptides, suggesting polymorphism of apoB-100 at the protein and DNA levels. Secondary structure predictions reveal an unusual pattern for apolipoproteins, consisting of beta-structure (24%), alpha-helical content (33%), and random structure (30%). Ten amphipathic helical regions of 10-24 residues were identified. This carboxyl-terminal fragment of apoB-100 is considerably more hydrophobic than other apolipoproteins with known structure. Its lipid binding regions might include stretches of highly hydrophobic beta-sheets as well as amphipathic helices. Our findings on apoB structure might be important for understanding the role of apoB-100-containing lipoproteins in atherosclerosis.

Pulmonary elimination of 5-fluorouracil in anesthetized rats

The pharmacokinetics of 5-fluorouracil (5-FU) was investigated in tumor-free anesthetized rats. Blood samples in the carotid artery and in the right atrium were sampled by cannulation during the steady-state infusion of 5-FU. Serum and blood samples were assayed by HPLC. After comparing the steady-state concentration of 5-FU in the right carotid artery with that in the right atrium, it was concluded that there was no pulmonary elimination of 5-FU in the anesthetized rat.

Human liver fatty acid binding protein cDNA and amino acid sequence. Functional and evolutionary implications

Human liver fatty acid binding protein (L-FABP) cDNA clones were identified in a liver cDNA library. The two longest clones were completely sequenced. The nucleotide sequence predicts a protein of 127 amino acid residues. Identity of the clones was confirmed by limited amino acid sequence analysis of purified human L-FABP peptides and Edman degradation of radiolabeled in vitro translated FABP. Statistical analysis of the amino acid and mRNA sequences of human L-FABP, rat L-FABP, rat intestinal (I-) FABP, and mouse 422 protein indicates that the human and rat L-FABPs are highly homologous and that L-FABP and I-FABP diverged a long time ago (approximately 650-690 million years ago), although they are more closely related to each other than either of them is to 422 protein. Secondary structure predictions from the primary sequence of human and rat L-FABP reveal a region (residues 12-30) that might be the putative fatty acid binding domain of the two L-FABPs. Knowledge of the primary amino acid sequence of L-FABP and possible functional domains will be pivotal in further defining and understanding the mechanism of ligand binding and transfer by this protein.

Identification of peptides containing tryptophan, tyrosine, and phenylalanine using photodiode-array spectrophotometry

The characteristic absorption spectra of aromatic amino acids between 240 and 310 nm were used to identify tryptophan, tyrosine, and phenylalanine-containing peptides. In acidic solution, the absorption spectra of these amino acids exhibit minima or maxima at 255, 270, and 286 nm. Based on these characteristics, the content of the aromatic amino acid in peptide can be estimated. For this study, 2 nmol of tryptic peptides from human apolipoprotein A-1 was separated by high-performance liquid chromatography using a reverse-phase column. The peptide fragments were monitored by a photodiode-array spectrophotometer. This new approach offers a rapid, simple, sensitive, and direct identification of peptides containing aromatic amino acids. Those containing Trp, which may be of interest for DNA sequencing and important in sequence analysis of proteins, can be selectively purified using this technique.

White count, pH and lactate in ascites in the diagnosis of spontaneous bacterial peritonitis

In order to evaluate the diagnostic accuracy of ascitic pH and lactate for early confirmation of spontaneous bacterial peritonitis (SBP), 109 consecutive patients with ascites were studied. The mean ascitic leukocyte [white blood cell (WBC)] and polymorphonuclear cell (PMN) counts, pH and lactate levels in 42 patients with sterile "normal" ascites were 124 +/- 157 per mm3, 41 +/- 77 per mm3, 7.502 +/- 0.097 and 11.1 +/- 7.9 mg per dl, respectively. Mean ascitic WBC and PMN counts were significantly increased in 10 patients with SBP (10,452 +/- 8,091 and 9,522 +/- 7,470 per mm3), in 10 patients with bloody ascites (2,591 +/- 4,284 and 1,057 +/- 1,494 per mm3) and in 11 patients with cytology positive malignant ascites (1,529 +/- 2,071 and 868 +/- 1,601 per mm3) (p less than 0.001). Mean ascitic pH was significantly reduced in SBP (7.335 +/- 0.048), in bloody ascites (7.384 +/- 0.037) and in cytology positive malignant ascites (7.355 +/- 0.167) (p less than 0.001). Mean ascitic lactate was also significantly elevated in these three groups of patients (36.8 +/- 17.0, 42.8 +/- 35.8 and 24.0 +/- 17.5 mg per dl, respectively; p less than 0.001) as well as in patients with bacteremia (51.6 +/- 78.0 mg per dl, p less than 0.005). However, ascitic pH less than 7.31, ascitic lactate greater than 33 mg per dl were observed only in three of the patients with SBP.(ABSTRACT TRUNCATED AT 250 WORDS)

[Primary structure of human class II histocompatibility antigens (HLA-D). II. Separation of alpha from beta-chains of HLA-D from a homozygous lymphoblastoid B cell line, H2LCL (HLA-A3,3;B7,7;Dw2,2;MT1,1;DC1,1;MB1,1), and characterization of the isolated chain]

In a previous communication we described the preparation of the alpha/beta-chain complex of HLA-D membrane antigens from a homozygous lymphoblastoid B cell line, H2LCL (HLA-A3,3; B7,7; Dw2,2; DR2,2; MT1,1; DC1,1; MB1,1). In this paper we present the separation of the alpha- and beta-chains in quantitative scale using hydroxylapatite chromatography with a pH 7.15 phosphate buffer, containing sodium dodecyl sulfate. An alternative isolation procedure is electrophoresis, taking advantage of the different isoelectric points of the alpha- and beta-chains. The relative molecular masses, the isoelectric points and the N-terminal sequences are discussed and compared with the results of other investigators. Remarkable is the polymorphism of both the chains, especially the beta-chains. The importance of the previously described three step purification procedure for the preparation of these antigens for sequence studies has been pointed out.

Determinants for hepatitis B e antigen clearance in chronic type B hepatitis

A 6-year (mean 24.5 months) longitudinal study has been undertaken in 237 HBeAg-positive patients with clinicopathologically verified chronic hepatitis. HBeAg clearance occurred in 74 patients at a rate of 16% per year, and a cumulative probability of 67% at the end of a 5-year follow-up. HBeAg clearance was preceded by a temporary "exacerbation" with SGPT greater than 300 IU/L in 62% of the patients. On the other hand, irrespective of the level of SGPT elevation, only 23% of such exacerbations were followed by HBeAg clearance. Further analysis indicates that alphafetoprotein greater than 100 ng/ml, frequently associated with bridging hepatic necrosis, during "exacerbation" predicts HBeAg clearance. In addition, patients with chronic lobular hepatitis and chronic active hepatitis have a higher annual HBeAg clearance rate than patients with chronic persistent hepatitis and nonspecific histologic changes (greater than 15% vs less than 8%, P less than 0.03). Short-term immunosuppressive treatment did not delay HBeAg seroconversion. Male patients had a higher annual HBeAg clearance rate than female patients (18.2% vs 8.7%, P less than 0.05). It was concluded that, in addition to the time factor, the nature of chronic hepatitis, the extent of hepatic damage during "exacerbation", and the sex of the patients are important determinants for HBeAg clearance.

Primary structure of human class II histocompatibility antigens. Reversed-phase high-performance liquid chromatography for integral membrane proteins

The amino acid sequence of the human HLA-DR2 class II antigen was determined with the aid of high-performance liquid chromatography. By applying exclusively Hypersil-ODS as the stationary phase in combination with three buffer systems, the amino acid sequences of the extracellular parts of the DR alpha- and DR beta-chains could be established. Moreover, the sensitivity of the procedure allowed the determination of the primary structures of additional class II polypeptides isolated together with the DR2 alpha- and the DR2 beta-chains. Significant insight into the heterogeneity of class II molecules was thereby obtained. In addition, a simple, rapid and selective method of general applicability is described for the isolation of membrane fragments of integral membrane proteins. Using Sep-Pak cartridges with a mobile phase containing 60% formic acid and varying 1-propanol concentrations, the highly hydrophobic peptides can selectively be separated from the hydrophilic fragments.

Peripheral T-cell subsets in chronic type B hepatitis: correlation with biochemical and histological activities and hepatitis B e antigen/antibody status

Peripheral T-cell subsets in 77 patients with hepatitis B surface antigen (HBsAg)-positive chronic liver diseases were studied by indirect immunofluorescence using murine monoclonal antibodies against all peripheral T cells (OKT3), T-helper/inducer cells (OKT4), and T-cytoxic/suppressor cells (OKT8). OKT4/OKT8 ratios were significantly reduced in patients with hepatitis B e antigen (HBeAg)-positive chronic liver diseases, including 28 patients with chronic active hepatitis (CAH) (P less than 0.001) and 15 with chronic persistent hepatitis (CPH) (P less than 0.001). OKT4/OKT8 ratios were significantly lower in 21 HBeAg-negative patients with CAH (P less than 0.05), as compared to those of 17 normal controls, while T-cell subsets in 13 patients with HBeAg-negative CPH were essentially normal. Low OKT4/OKT8 ratios significantly correlated with HBeAg positivity (P less than 0.001) and CAH (P less than 0.05), as assessed with multiple regression. There was a significant negative correlation between OKT4/OKT8 ratios and serum glutamic-pyruvic transaminase (SGPT) levels (r = -0.37; P less than 0.01). It was concluded that in chronic hepatitis B virus infection, low OKT4/OKT8 ratios are closely related to active viral replication and more severe histological and biochemical activity.

Separation of dimethylaminoazobenzenethiohydantoin amino acids by high-performance liquid chromatography at low picomole concentrations

The separation of all common dimethylaminoazobenzenethiohydantoin (DABTH) amino acids derived from modified Edman sequencing can be achieved by using high-performance liquid chromatography. All derivatives, including DABTH-Ile and DABTH-Leu, can be readily separated in a solvent mixture of sodium acetate buffer and 1% ethylene dichloride in acetonitrile. The high absorbance of the DABTH amino acids at 436 nm makes possible the quantitative determination of these derivatives at picomole concentrations in a relatively short time (30-40 min).

Age-specific prevalence and significance of hepatitis B e antigen and antibody in chronic hepatitis B virus infection in Taiwan: a comparison among asymptomatic carriers, chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma

The age-specific prevalence of hepatitis B e antigen (HBeAg) and its antibody (anti-HBe) were studied by radioimmunoassay, and compared in a large series of patients with chronic hepatitis B virus (HBV) infection, including 268 asymptomatic carriers, 389 chronic hepatitis, 114 liver cirrhosis, and 278 hepatocellular carcinoma (HCC). The prevalence of HBeAg/anti-HBe in asymptomatic carriers and patients with chronic hepatitis correlated closely with age as HBeAg prevalence decreased and anti-HBe prevalence increased with increasing age (P less than 0.0005), and is probably due to high infection rate at young age in Taiwan. The prevalence of HBeAg in patients with both cirrhosis and HCC are much significantly lower and had no correlation with age. Two peaks of age-specific prevalence of HBeAg and anti-HBe were observed in patients with HCC, implicating two patterns of HBV infection in these patients. The difference in the prevalence of HBeAg and anti-HBe might indicate that asymptomatic carriers, chronic hepatitis, liver cirrhosis, and HCC are sequential sequelae of HBV infection.

The architecture of the animal fatty acid synthetase. II. Separation of the core and thioesterase functions and determination of the N-C orientation of the subunit

Chicken fatty acid synthetase is cleaved by alpha-chymotrypsin into two fragments of molecular weight 230,000 and 33,000. These fragments may be easily separated by ammonium sulfate fractionation and gel filtration to yield pure preparations. The large 230,000-Da fragment contains all of the core activities of the fatty acid synthetic sequence i.e. acetyl and malonyl transacylases, condensing enzyme, beta-ketoacyl and enoyl reductases, the dehydratase, and the acyl carrier protein. The smaller 33,000-Da fragment retains the thioesterase activity which catalyzes the release of the completed acyl chains from the complex. Antibodies against the purified thioesterase fragment cross-react with analogous (Mr 33,000) peptides released from the complex by other proteases, as well as with all proteolytic intermediates that were predicted by peptide mapping to contain the thioesterase segment (Mattick, J. S., Tsukamoto, Y., Nickless, J., and Wakil, S. J. (1983) J. Biol. Chem. 258, 15291-15299). Amino acid sequence analyses demonstrate that the thioesterase domain is located at the carboxyl terminus of the synthetase monomer, thereby orienting the proteolytic (and functional) sites within the complex with respect to the direction of transcription and translation.

Retinal hexokinase: kinetic properties and the effect of cyclic 3',5'-adenosine monophosphate

We measured hexokinase (EC 2.7.1.1) activity in particulate and soluble fractions isolated from bullfrog (Rana catesbeiana) retinas. Seventy-three percent of the hexokinase (HK) activity was associated with the particulate fraction, 27% with the soluble fraction. Both HK fractions could phosphorylate fructose, glucose, 2-deoxy-D-glucose, and mannose, but not galactose. The Km for glucose was 0.14 mM, for 2-deoxy-D-glucose, 3.6 mM. With glucose as substrate, the Vmax for particulate HK was 125-148 microM retina-1 min-1, for soluble HK, 37 microM retina-1 min-1. Product inhibition of particulate HK activity by glucose 6-phosphate was marked, whereas 2-deoxy-D-glucose 6-phosphate did not inhibit the activity. Cyclic AMP stimulated the HK activity of both retinal fractions nearly twofold at concentrations of 0.2-0.8 mM; AMP was much less effective in this regard.

The complete primary structure of the allosteric L-lactate dehydrogenase from Lactobacillus casei

The polypeptide chain of the allosteric L-lactate dehydrogenase (EC 1.1.1.27) of Lactobacillus casei consists of 325 amino acid residues. Despite the strikingly different enzymatic characteristics of the allosteric L-lactate dehydrogenase of L. casei and of the non-allosteric vertebrate enzymes, the sequence of the allosteric enzyme shows a distinct homology with that of the non-allosteric vertebrate enzymes (average identity: 37%). An especially high sequence homology can be identified within the active center (average identity: 70%). A clear deviation of the L. casei enzyme from the vertebrate enzyme is the lack of the first 12 amino acid residues at the N terminus and an additional 7 amino acid residues at the C terminus. The localization of the binding site of the allosteric effector D-fructose 1,6-bisphosphate and pH and effector-induced changes of the spectroscopic properties are discussed on the basis of the primary structure.

Blue-sensitive rod input to bipolar and ganglion cells of the Xenopus retina

Intracellular recordings were obtained from chromatic and non-chromatic bipolar cells, identified by Lucifer yellow injection in the Xenopus retina. The chromatic cells, which lacked center-surround organization, were short wavelength hyperpolarizing (lambda max 445 nm) and long wavelength depolarizing. Under photopic conditions the depolarizing component was driven by 612 nm cones, but under mesopic conditions it appeared that 524 nm rods also constituted an input to the response. The non-chromatic bipolars encountered were of the off-center (hyperpolarizing) variety, with an active antagonistic surround, and peak spectral sensitivity in the red portion of the spectrum. Extracellular recordings were obtained from color-coded ganglion cells classified as type 1 or 2 in frog retina by Maturana et al. (1966) [J. gen. Physiol. 43, 129-175] and Bäckström and Reuter (1975) [J. Physiol. 246, 79-107]. The spectral sensitivity of the long latency "on" component was matched by the density spectrum of the 445 nm rod. This response component lacked center-surround organization and showed a relatively broad area of spatial integration. In contrast, a short latency component had a spectral sensitivity matched by the 612 nm cone pigment under photopic conditions, was either "on" or "off" center, showed center-surround organization and had a relatively small area of spatial integration. We speculate that in Xenopus retina, both chromatic and non-chromatic bipolar cells provide synaptic input to the class 1,2 ganglion cell.

Transport and phosphorylation of 2-deoxy-D-glucose by amphibian retina. Effects of light and darkness

We studied the uptake of 2-deoxy-D-glucose (2DG) and the synthesis of its phosphorylated product 2DG-6-phosphate (2DG-6P) by the retinas of the clawed frog (Xenopus laevis) and the bullfrog (Rana catesbeiana). Autoradiographs showed that most of the retinal 2DG uptake is by the photoreceptor layer. The 2DG accumulation by isolated Xenopus retinas was time and concentration dependent. The Kt for transport was 5.05 mM; Vmax was 6.99 X 10(-10) mol . mg-1 tissue wet weight min-1. The Km for 2DG-6P formation was estimated to be 2-3 mM and Vmax to be approximately 4 x 10(-9) mol . mg-1 min-1. 2DG uptake was inhibited competitively by glucose with a Ki of 2.29 mM. Exposure to light reduced 2DG uptake by no more than 10% as compared with dark uptake. Low sodium or ouabain (10(-4)-10(-7) M) treatment did not significantly alter 2DG uptake as compared with control retinas. In experiments upon intact, anesthetized bullfrogs, light reduced both the total amount of radioactivity acquired by the retina and the fraction of 2DG-6P present. The results are discussed in terms of the fraction of energy consumed by the retina required to maintain the photoreceptor dark current.

Uptake and localization of 3H-2 deoxy-D-glucose by retinal photoreceptors

Following dark incubation of isolated retinas of Xenopus laevis in Ringer solution supplemented with 3H-2-Deoxy-D-glucose (2DG), virtually all of the uptake of the label was by the inner segments and synaptic bases of the photoreceptor cells. Autoradiographs prepared from conventionally fixed tissue showed the same cellular distribution of label as those prepared from identically incubated, unfixed, freeze-dried retinas. However, fixation removed about 77% of the total counts. This fixation-labile, soluble fraction was identified as being primarily 2DG-6 phosphate by thin-layer chromatography. The remaining insoluble fraction corresponded in distribution to glycogen grains. In cones, glycogen is stored primarily in the paraboloid, whereas in rods it is distributed throughout the inner segment and synaptic base. EM autoradiographs illustrated that these were the sites over which fixation-resistant 2DG label was localized. Measurements of radioactivity associated with extracts of retinal glycogen following 2DG incubation demonstrated that a disproportionately high fraction of total counts were associated with the glycogen fraction. We conclude that in the amphibian retina 2DG may be incorporated into glycogen.

[Primary structure of class II human histocompatibility antigens. 1st communication. Amino acid sequence of the N-terminal 198 residues of the beta chain of a HLA-Dw2,2;DR2,2-alloantigen (author's transl)]

The beta-chains of HLA-D/DR antigens from a lymphoblastoid homozygous cell line (HLA-A3,3;B7,7;-Dw2,2;DR2,2) were purified by an exclusively chemical three step procedure: 1) Nonidet P-40/CM-cellulose ion-exchange-, 2) Na-dodecyl sulfate/sephacryl S-300- and 3) Na-dodecyl sulfate/hydroxylapatite chromatography. The amino acid sequence of the beta chain was established up to position 198. These residues comprise the extra-cellular part of the molecule which consists of two domains each probably containing a disulfide bridge, like immunoglobulin L chains. Within the first domain the carbohydrate moiety is attached to asparagine in position 19. Sequence work was hampered by the fact that the beta chain preparation of the HLA-Dw2,2;DR2,2 antigen actually consists of a pool of beta chains. The beta chain, the sequence of which has now been established, represents about 70% of the beta chain pool. The remaining 30% consist of at least 6 more chains which are homologous among one another as well as to the described beta chain. Since the antigens were gained from a homozygous lymphoblastoid cell-line our results indicate that the HLA-D region codes for at least 7 beta-chains and must therefore consist of a cluster of beta chain genes.

[Chromatography and rechromatography in high-performance liquid chromatography of peptide mixtures: the complete primary structure of an immunoglobulin L-chain of kappa-type, subgroup I (Bence-Jones Protein Den) (author's transl)]

In continuation of our work on the separation of enzymatic hydrolysates by high-pressure liquid chromatography with reverse-phases we present two new buffer systems: firstly 0.005M potassium phosphate, pH 6.0 and secondly aqueous trifluoroacetic acid, pH 2.15. As organic solvent acetonitrile is always used. The excellent properties are demonstrated by the separation of the tryptic peptides of Bence-Jones protein Den (Mr = 23000). Like ammoniumacetate these buffers are well suited for the first separation of peptide mixtures but can be used rather effectively in rechromatographies. If peaks are not or not fully resolved during the first chromatography they can be separated by a rechromatography in one of the other systems. This was most successful since in both cases the same high resolving technique is employed. From the primary separation 14 peptides could be isolated in analytically pure form. The remaining fragments were completely purified after one rechromatography. The amino acid analysis yielded also integer numbers and by a modified Edman degradation the primary structure could be determined. As with protein Wes (Kratzin, H., Yang, C.Y., Krusche, T.U. & Hilschmann, N. (1980) Hoppe-Seyler's Z. Physiol. Chem. 361, 1591--1598) all the peptides were recovered after high-pressure liquid chromatography, none was missing. From these data and from homology reasons the complete amino acid sequence of protein Den could be established. It contains 214 residues and belongs to subgroup I of the kappa-chains. The valine residue in position 191 indicates that it belongs to allotype Inv b+.

[Preparative separation of the tryptic hydrolysate of a protein by high-pressure liquid chromatography. The primary structure of a monoclonal L-chain of k-type, subgroup I (Bence-Jones Protein Wes) (author's transl)]

The tryptic hydrolysate of Bence-Jones protein Wes (Mr = 23000) was separated by high-pressure liquid chromatography in a volatile buffer system on a reversed-phase column. From the resulting 22 peptides 18 yielded integer numbers after amino acid analysis. They could be used directly for a modified Edman degradation. Two peptides were not separated by this procedure, two were missing. Under different conditions these four peptides could also be prepared in pure form. 3 mg was sufficient to elucidate the primary structure of the variable part of this protein completely. The arrangement of the tryptic peptides was deduced by homology to other k=chains. Protein Wes contains 214 residues and belongs to subgroup I of the k-chains. The valine residue in position 191 indicates that it belongs to allotype Inv b+.

Studies of trachoma in families on Taiwan

This study was undertaken to clarify the natural history and pathogenesis of trachoma. A group of families who live in a formerly trachoma hyperendemic area of Southern Taiwan were placed under continuous surveillance. The development in recent years of the micro immunofluorescence test for trachoma antibody, along with improved cell culture isolation methods, have allowed this surveillance to include repeated effective laboratory studies in addition to clinical observations. After four years' study of one group of families and three years of another, a number of interesting findings have been obtained. Evidence is presented supporting our hypothesis that trachoma is a disease of immumopathology and results from repeated reinfections with the trachoma organisms. The clinical findings of papillae, especially those of an acute nature, has been the clinical finding most closely associated with the isolation of the organism and the demonstration of antibody. Evidence is presented that transmission of the organism is usually within the family group. Although only trachoma immunotypes B and C previously had been associated with trachoma infection on Taiwan, data is presented from one family in which type D infections occurred. While a series of new and reinfections with trachoma organisms were demonstrated in some of the families under observation, the majority of the families not only showed no new infections but showed spontaneous healing or disappearance of clinical and laboratory evidence of trachoma infection. This tendency of active trachoma infection to disappear from a family in the absence of transmission of the organism parallels the rapid fall and prevalence of active trachoma on Taiwan during the past decade.

On-line data reduction with a prism spectrometer

We describe the hardware and software aspects of an automatic spectroscopy system based upon a programmable calculator and a prism monochromator. Linear spectral presentation is obtained by a fourpoint Aitken-Lagrange interpolation performed at each data point. The interpolation subroutine, which is also useful for data logging with thermocouples, is described in detail. Both open- and closed-loop applications of the system to reflectance and modulation spectroscopies are discussed, and additional uses are suggested.

Comparative studies on the detoxification of aflatoxins by sodium hypochlorite and commercial bleaches

Cultures of Aspergillus flavus and aflatoxins were destroyed by a commercial bleach (Clorox; active ingredient, NaOCl) or analytical reagent grade NaOCl at 7.0 x 10(-3) M NaOCl in 5 days. Addition of Clorox or NaOCl at 2.8 x 10(-3) M to the fungal growth medium prior to inoculation completely inhibited the fungal growth. Aflatoxin production was inversely proportional to the logarithm of NaOCl concentration and time of treatment. Clorox and NaOCl were equally effective on aflatoxins, but fungal cells were lysed more readily by Clorox than by NaOCl. Mycelia older than 8 days lysed more readily than younger ones. Most conidia survived concentrations below 1.4 x 10(-3) M. The lowest effective concentration for a 2-hr treatment was 8.8 x 10(-3) M which is well below the Clorox concentration recommended for routine laboratory decontamination of aflatoxins. Mice and rats injected with aflatoxins and aflatoxins incompletely destroyed by Clorox died within 72 hr and had typical liver and kidney damage caused by aflatoxins. However, animals injected with NaOCl or Clorox or Clorox-destroyed aflatoxin extracts survived and showed no obvious liver or kidney damage.

Clinical evaluation of the Taiwan trachoma control programme

Following a clinical trial in 1959-60 and a prevalence survey in 1960-61, a community-wide trachoma treatment programme was instituted in Taiwan. A reexamination in 1968-69 of a subsample of the localities included in the 1960-61 survey provided the basis for a clinical evaluation of the programme.Except in areas of very high endemicity in 1960-61, trachoma appears to have ceased to be, or is in the process of ceasing to be, an important public health problem. A reduction in the number of cases that were active in 1960-61 has since resulted in reducing both the incidence and the severity of the disease. Cases showing signs of past experience of the disease (healed cases), as well as cases with grave irreversible sequelae or complications, belong to the pretreatment cohort and are moving along "time" without being replaced.In communities with an initially very high endemicity it is open to question whether the incidence of the disease has been reduced to the level at which it will fail to perpetuate itself. The results of a very limited survey conducted in 1970 are encouraging: a repeat sample survey is planned for 1972.