A study into the natural occurrence of inorganic ions relevant to forensic explosives investigations on human hands.

The natural occurrence of 16 inorganic ions relevant to forensic explosives investigations on human hands was studied to support the evaluation of activity-level propositions when such traces are found on the hands or in the fingerprints of a suspect. A total of 594 hand swab extracts from 297 participants throughout Europe and the United States of America were analyzed using Ion Chromatography - Mass Spectrometry. The data provides a reference framework for future covert investigations and forensic casework. The results indicate that thiocyanate, chlorate, nitrite, lithium, strontium, and barium are rarely detected on the hands of individuals who have had no direct contact with explosives (P<0.03) and in quantities below 6 µg. Perchlorate contamination sporadically occurs without deliberately handling perchlorates (P=0.03), albeit at low levels (<12 µg). It also seems that the presence of perchlorate on hands is generally related to professions that involve explosives. Detecting substantial amounts of any of these rare ions on a suspect's hands would require a specific explanation. Because legitimate activities exist that can also result in elevated levels of ions of interest on hands, the context surrounding their presence has to be carefully assessed for each individual case.

Probing steric and hydrophobic effects on enzyme-substrate interactions by protein engineering.

Steric and hydrophobic effects on substrate specificity were probed by protein engineering of subtilisin. Subtilisin has broad peptidase specificity and contains a large hydrophobic substrate binding cleft. A conserved glycine (Gly(166)), located at the bottom of the substrate binding left, was replaced by 12 nonionic amino acids by the cassette mutagenesis method. Mutant enzymes showed large changes in specificity toward substrates of increasing size and hydrophobicity. In general, the catalytic efficiency (k(cat)/K(m)) toward small hydrophobic substrates was increased (up to 16 times) by hydrophobic substitutions at position 166 in the binding cleft. Exceeding the optimal binding volume of the cleft ( approximately 160 A(3)), by enlarging either the substrate side chain or the side chain at position 166, evoked precipitous drops in catalytic efficiency (k(cat)/K(m)) (up to 5000 times) as a result of steric hindrance.

Monoclonal antibodies to human progesterone receptor: characterization by biochemical and immunohistochemical techniques.

Progesterone receptor (PR) from a human endometrial carcinoma (EnCa 101) grown in nude mice consists of two hormone-binding proteins with mol wt around 116,000 and 85,000. To generate monoclonal antibodies against this receptor, PR was partially purified from EnCa 101 and used to immunize Robertsonian mice. Immune mouse spleens were fused with HL-1 Friendly myeloma-653 cells, and hybridomas were screened by solid phase dot-blot assay and double antibody precipitation. Seven stable hybridomas were obtained, designated hPRa 1-7. Subisotyping revealed that hPRa 1 and 6 were immunoglobulin G2b, while the remainder were immunoglobulin G1. Ultracentrifugation in high salt sucrose gradients showed that six of the seven antibodies effected a shift of [3H]progestin-labeled PR from EnCa 101; only hPRa 4 was ineffective in this regard. Protein blots of EnCa 101 cytosols and DEAE eluates revealed that hPRa 1, 3, 4, 5, and 7 recognized both PR proteins equally. hPRa 2 recognized principally the 116,000 mol wt PR protein; it recognized the lower mol wt PR protein very poorly if at all, whereas hPRa 6 recognized only the 116,000 mol wt protein. Interestingly, the latter was consistently detected as a closely migrating triplet. Immunolocalization of PR by hPRa 1-7 in tissue sections was confined to nuclei of target tissues and varied in intensity: hPRa 7 greater than 3 = 5 greater than 6 = 2 greater than 1 greater than 4. In proliferative phase uterus, the intensity of staining was ranked: endometrial gland nuclei (3+) greater than myometrial cell nuclei (2-3+) greater than endometrial stromal cell nuclei (0-1+). Thus, seven monoclonal antibodies directed against human PR have been prepared, and their suitability for the study of PR by biochemical and immunohistochemical techniques has been demonstrated.

Female gene expression in the seminal vesicle of mice after prenatal exposure to diethylstilbestrol.

Previous studies from our laboratory on the feminization of the male mouse reproductive tract after prenatal exposure to diethylstilbestrol (DES) showed that the mRNA for the major estrogen-inducible uterine secretory protein, lactoferrin (LF), was constitutively expressed in the seminal vesicle of male mice exposed prenatally to DES, but not in the seminal vesicle of control mice. After castration, treatment with 17 beta-estradiol (20 micrograms/kg.day) for 3 days induced the LF mRNA in the seminal vesicle of both control and prenatally DES-exposed mice; however, the levels in DES-treated tissues were approximately 6-fold higher than those in control tissue. This report describes the presence of LF in seminal vesicle tissues and secretions of prenatally DES-exposed mice, as determined by immunohistochemistry and Western blot analysis. Further, these data are correlated with immunolocalization of the estrogen receptor in the seminal vesicle tissue. We conclude that the seminal vesicle of prenatally DES-exposed male mice has acquired two key characteristics of female tissues, namely LF production/regulation and estrogen receptor localization/distribution similar to that in uterine tissues.

Optimal filtering of radiographic image sequences using simultaneous diagonalization.

A method is presented for the processing of temporal image sequences to enhance a desired process and suppress an undesired (interfering) process and random noise. Furthermore, the processed information is contained in a single frame which is easily interpreted. The method consists of collecting information about the desired and interfering processes from the frames of the given image sequence. The information is in the form of vectors that characterize the temporal properties of the processes. Matrices are formed by performing outer product expansions on these vectors and an eigenvector matrix is found which will simultaneously diagonalize these matrices. By calculating the inner product of a selected eigenvector from this matrix with the image sequence, an enhanced image of the desired process is obtained. A parameter can be adjusted which will increase the amount of suppression for either random noise or the interfering process. At one limit setting of this parameter, a matched filter for the desired process results, while at the other extreme, very high attenuation of the interfering process will occur. Simulations which demonstrate the effectiveness of this technique are presented along with results obtained by processing a radiographic temporal image sequence.

Spatially invariant image sequences.

The authors define linearly additive spatially invariant image sequences and present an explicit mathematical model for describing them. In such a sequence, all objects are positionally invariant in each image of the sequence but have varying gray-scale contributions to the successive images of the sequence. The various components (features or processes) of the scene or object contribute additively to each image of the sequence, but each component has a characteristic variation (signature) from image to image due to the variation of the function, parameter or spectral band over the sequence. Objects with different spectral characteristics will have different image sequence signatures which can be used to distinguish them. Also presented are the general formulation, derivation, and explicit expression for the linear filter, called the simultaneous diagonalization (SD) filter, that calculates a single new image from the sequence such that a desired process is emphasized and any number of undesired processes is suppressed in the filtered image.

Purification and characterization of 2,5-diketo-D-gluconate reductase from Corynebacterium sp.

2,5-Diketo-D-gluconate reductase, a novel enzyme that catalyzes the stereospecific NADPH-dependent reduction of 2,5-diketo-D-gluconate to 2-keto-L-gulonate, has been purified to homogeneity by sequential anion exchange, Cibacron blue F3GA affinity, and gel permeation chromatography from Corynebacterium sp. ATCC 31090. Molecular weight of the native form, determined by gel permeation chromatography, is 35,000 +/- 2,000. The subunit molecular weight, determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis is 34,000; thus, the enzyme is active as a monomer. A pI value of 4.4 is measured for the enzyme. Amino- and carboxyl-terminal sequences are consistent with that predicted by the DNA sequence of the reductase gene. At 25 degrees C, pH 6.4, the turnover number is 500 min-1, and the apparent Km values for 2,5-diketo-D-gluconate and NADPH are 26 mM and 10 microM, respectively. The enzyme is specific for NADPH, but the sugar binding site will also accept 5-keto-D-fructose and dihydroxyacetone as substrates. The enzyme is active over a broad pH range (pH 5-8) for the reduction of 2,5-diketo-D-gluconate; a sharp optimum at pH 9.2 is observed for the oxidation of 2-keto-L-gulonate. A Keq value of 5.6 X 10(-13) M indicates that reduction of substrate by NADPH is highly preferred. An activation energy of 12.3 kcal mol-1 is measured. Enzyme turnover is slow relative to dehydration of the gem-diol at C-5 of the substrate.

Partial purification by affinity chromatography of tyrosine aminotransferase-synthesizing ribosomes from hepatoma tissue culture cells.

This report describes a cell-free protein-synthesizing system derived from hepatoma tissue culture cells in which the synthesis of tyrosine aminotransferase is enhanced in relation to total protein synthesis. The enhancement was achieved by using affinity chromatography to select a specific fraction of ribosomes in which the proportion of tyrosine aminotransferase synthesis is higher than it is in unfractionated ribosomes.

Pancreatic cholera: beneficial effects of treatment with streptozotocin.

Two patients with pancreatic cholera and islet-cell carcinoma were treated with intra-arterial streptozotocin. Before therapy, they had stool volumes from 2 to 8 liters per day and required 200 to 800 mEq per day of supplemental potassium. After three to five doses of streptozotocin (1.5 per square meter), both stool volume and number and size of hepatic metastases decreased markedly. One patient has had normally formed stools for 12 months; the other had a 90 per cent reduction in stool volume for 13 months with additional therapy. Both patients' serum potassium returned to normal without need for supplementation. Jejunal adenylate cyclase activity was normal in both, and plasma vasoactive intestinal peptide was detectable in only one. After chemotherapy, these findings showed no consistent change. Pharmacologic studies suggest that arterial administration increased either tumor or hepatic extraction (or both) of streptozotocin by two times and decreased renal exposure to this nephrotoxic drug by one third.

Fluctuations of lactoferrin protein and messenger ribonucleic acid in the reproductive tract of the mouse during the estrous cycle.

The physiological role of lactoferrin (LF), the major estrogen-inducible protein in the murine uterus, is unclear; however, LF may be a useful marker for the study of estrogen action in the uterus. Thus, the expression of LF mRNA and the localization of the protein in genital tract tissues and secretions of female mice (6-8 wk old) at different stages of the estrous cycle were investigated. Uterine luminal fluid (ULF) was analyzed for LF by means of gel electrophoresis and Western blot techniques; LF mRNA and protein were identified in reproductive tract tissues through in situ hybridization and immunocytochemistry. At diestrus, the level of LF mRNA was low, and staining for the protein was very light in uterine epithelial cells; LF was undetectable in ULF. At proestrus, LF mRNA and protein increased in the uterine epithelium and LF was readily detectable in ULF. LF mRNA and protein reached the highest levels at estrus. At early metestrus as compared to estrus, LF mRNA and protein were detected in decreasing amounts in uterine epithelial cells; the protein was undetected in ULF. By late metestrus and diestrus, LF mRNA and protein returned to a low level, and the protein was undetectable in ULF. LF protein was also demonstrated by immunocytochemistry in the epithelium of the oviduct, cervix, and vagina. LF protein fluctuation similar to that observed in the uterus was seen in these tissues; however, the uterus demonstrated the most dramatic changes in the number of epithelial cells involved in LF production during the estrous cycle. In summary, LF mRNA and its expression in uterine epithelial cells of the mouse varied with the stage of the estrous cycle. These results, combined with previously reported findings that LF is a major constituent of mouse ULF under the influence of estrogen, suggest that LF may play an important role in normal reproductive processes.

Expression of hepatitis B virus surface antigen in yeast.

The structural gene of Hepatitis B virus surface protein (HBsAg) was introduced into a plasmid capable of autonomous replication and selection in both the yeast Saccharomyces cerevisiae and E. coli. In this plasmid transcription of the HBsAg is initiated by the 5'-flanking sequence of the yeast 3-phosphoglycerate kinase (PGK) gene and terminated by the 3'-flanking region of the yeast TRP1 gene. Yeast cells containing this plasmid produce a new major species of mRNA of 1200 nucleotides in length coding for HBsAg. Viral surface antigen is made in nonglycosylated form at a level of about 1-2 percent of total yeast protein. A small fraction of this polypeptide (2-5 percent) is found in aggregated form upon yeast cell disruption by glass beads. This material is similar in size, density, and shape to the 22nm particle, isolated from the plasma of human hepatitis carriers, and induced comparable levels of HBsAg antibodies in mice when compared with the natural particle.