Identification of lead and other elements in ceramic glazes and housewares by 109Cd-induced X-ray fluorescence emission spectrometry

Radioisotope x-ray fluorescence spectrometry was investigated as a potential screening method for Pb and other elements in housewares. Thirty-six commercial houseware items and 87 ceramic test tiles (85 fired with hobby glazes and 2 blank bisques) were examined qualitatively for the presence of Pb by using 109Cd-induced L x-ray fluorescence emission spectrometry. For the housewares, the technique provided fast, nondestructive analysis of areas with about 10 cm diameters (general regions) to about 4 mm diameters (isolated design regions). Pb was found in 25 of 28 ceramicware items, in all 8 other housewares, and in all the test-tile glazes above the limit of detection of 1 count per second (cps) for Pb L beta x-rays. For housewares, Pb identification did not always correspond to Pb leachability. For 68 test-tile glazes labeled as containing Pb (39 of which were also labeled 'dinnerware safe' or 'safe for food containers'), count rates ranged from 290 to 730 cps, whereas for the other 17 glazes labeled (with one exception) 'non-toxic,' much lower count rates (5-61 cps) were obtained. Other elements found in the housewares or test glazes were As, Au, Ca, Co, Cr, Cu, Fe, Mn, Nb, Ni, Rb, Sr, Y, Zn, and Zr.

The role of external nonrigid ankle bracing in limiting ankle inversion

The purpose of this study was to measure the effectiveness of the nonrigid subtalar stabilizer (STS) ankle brace under conditions similar to an unexpected fall that could lead to a lateral ligament injury. The calcaneal inversion angles, times, and ground reaction forces were measured when the subject's right foot, bearing body weight, was suddenly inverted to a side slope of 22 degrees. Thirty subjects, 15 women and 15 men, participated in the study. The overall inversion drop was divided into two phases, free fall and loading. Based on the data of this study it is suggested that the major function of a brace is to restrict the amount of foot inversion during the fall before actual landing occurs rather than functioning as a force bypass for the lateral ligaments during loading after foot contact. The results showed that the brace significantly (p < 0.05) reduced the maximum calcaneal inversion angle from 27.4 +/- 6.1 to 18.3 +/- 6.0 degrees for the overall drop, significantly lengthened the inversion time from 0.14 +/- 0.04 to 0.18 +/- 0.04 s for the overall drop, and significantly reduced the calcaneal peak inversion velocity from 324.6 +/- 111.9 to 165.2 +/- 66.5 degrees/s during loading, and from 278.7 +/- 120.0 to 183.0 +/- 108.7 degrees/s for the overall drop. Following exercise, which incorporated lateral movements and sprinting, the STS ankle brace continued to provide significant (p < 0.05) reduction in the calcaneal inversion angle and velocity, although some of its effectiveness was reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

A pig model for advanced laparoscopic biliary procedures

Advanced laparoscopic biliary procedures can be undertaken in a pig model, but the small size of the normal common bile duct makes learning difficult. We have developed a prepared pig model of common bile duct ligation on which to practice advanced laparoscopic biliary surgery. The pig's distal common bile duct was occluded using several different methods via a minilaparotomy. Laparoscopic biliary procedures were undertaken 6-21 days later. The common bile duct became dilated to between 2 and 3 cm in diameter in all cases, and this was well tolerated by the animals. All advanced laparoscopic biliary procedures were possible, including choledochoscopy, exploration of the bile duct, and cholecystojejunostomy. Short-term common bile duct ligation is well tolerated in pigs and can be used to create a model for practicing advanced laparoscopic biliary procedures.

A comparison of tympanic thermometer readings to pulmonary artery catheter core temperature recordings

The purpose of this study was to determine the accuracy of FirstTemp (Intelligent Medical Systems, Carlsbad, CA) tympanic thermometer readings compared with core body temperatures obtained via pulmonary artery catheter (PAC). Five measurements were obtained on 19 cardiovascular surgery patients. Tympanic thermometer measurements tended to be higher than PAC measurements. However, most of the differences were not clinically significant. Differences found between right and left ear measurements were most likely due to poor measurement technique. When the correct technique is used, nurses can be confident that tympanic temperature readings are clinically accurate.

Radionuclides in domestic and imported foods in the United States, 1987-1992

Findings from the U.S. Food and Drug Administration's Radionuclides in Foods program are summarized for foods collected between October 1, 1986, and September 30, 1992. Concentrations of radionuclide activity in the Total Diet Study and reactor-survey foods were in Range 1 or low in Range II of the surveillance and control recommendations of the Federal Radiation Council; no control actions were suggested. Dietary intake of 90Sr continued the general decline observed since 1961. Approximately 2600 test portions of imported foods were analyzed for contamination associated with the Chernobyl nuclear accident. Concentrations of radionuclide activity were below limits of detection for the vast majority of the imported food test portions but were above the levels of concern for 23 portions. Since 1986, the fraction of imported food test portions having measurable amounts of contamination has steadily declined, as have the average concentrations of radionuclide activity; however, contamination is still occasionally found. Continued monitoring of both domestic and imported foods is planned.

Helium-3 from the Mantle: Primordial Signal or Cosmic Dust?

Helium-3 in hotspot magmas has been used as unambiguous evidence for the existence of a primordial, undegassed reservoir deep in the Earth's mantle. However, a large amount of helium-3 is delivered to the Earth's surface by interplanetary dust particles (IDPs). Recycling of deep-sea sediments containing these particles to the mantle, and eventual incorporation in magma, can explain the high helium-3/helium-4 ratios of hotspot magmas. Basafts with high helium-3/helium-4 ratios may represent degassing of helium introduced by ancient (probably 1.5 to 2.0 billion years old) pelagic sediments rather than degassing of primordial lower mantle material brought to the surface in plumes. Influx of IDPs can also explain the neon and siderophile compositions of mantle samples.

Bacillus subtilis mutants defective in bacteriophage phi 29 head assembly

Virus assembly mutants of asporogenous Bacillus subtilis defective in bacteriophage phi 29 head assembly were detected by the use of antibodies that reacted strongly with the free dodecameric phi 29 portal vertex composed of gene product 10 (gp10) but weakly with the portal vertex assembled into proheads or phage. Phage adsorption and the synthesis of phage proteins, DNA-gene product 3, and prohead RNA were normal in these mutants, but prohead and phage production was greatly reduced. The assembly defect was transferred to competent B. subtilis by transformation and transduction. PBS1 transduction showed that the vam locus was linked to Tn917 located at 317 degrees on the B. subtilis chromosome.

Laparoscopic gastrointestinal anastomoses

In a preliminary study of laparoscopic gastrointestinal anastomosis, a gastric outlet obstruction was created under laparoscopic control in six domestic pigs, weighing an average of 25 kg. A simultaneous gastroenterostomy was formed with an end-stapling device. All animals recovered clinically, and good anastomotic healing was documented 1 week postoperatively. The authors suggest that an end-stapling device could be one method of creating a gastrointestinal anastomosis for humans that is safe and reliable, allows rapid recovery and decreases hospital stay.

Use of spherical targets to minimize effects of neutron scattering by hydrogen in neutron capture prompt gamma-ray activation analysis

For hydrogenous targets that are thinner than they are wide, element sensitivities (counts.s-1.mg-1) for determining concentrations of elements by neutron capture prompt gamma-ray activation analysis (PGAA) are enhanced relative to sensitivities obtained from measurements on nonhydrogenous materials. These enhancements are caused mainly by elastic neutron scattering by H, which changes the average neutron fluence rate within the matrix. The magnitude of the effect depends on the macroscopic scattering and absorption cross sections and on the size, shape, and orientation of the target with respect to the neutron beam. Sensitivities increase linearly with H density for thin targets of constant size and shape and also vary with target shape. Theoretical work was shown that element sensitivities for hydrogenous targets in the form of spheres are least affected by neutron scattering. Methods were devised for creating solid spheres and for containing liquids in spherical shapes. Element sensitivities were determined for spheres and disks of several hydrogenous materials. For H, B, Cl, K, Br, and Cd, sensitivities for spheres were found to be less affected by neutron scattering. Exceptions were Sm and Gd sensitivities measured in liquids contained in quartz globes.

Thyroid stimulating hormone and prolactin responses to thyrotropin releasing hormone in nondepressed alcoholic inpatients

Thyroid stimulating hormone (TSH) and prolactin (PRL) responses to thyrotropin releasing hormone (TRH) stimulation are sometimes blunted in alcoholic subjects; however, the mechanisms involved in these phenomena have not been established. We hypothesized that elevations in free thyroid concentrations might be related to these abnormal responses and then tested that hypothesis in a sample of nondepressed alcoholic inpatients (n = 21). Four alcoholic patients had delta max TSH responses that were < 7 mIU/l; three had PRL responses at or below 8 micrograms/l. Baseline TSH was the only significant predictor of peak TSH; however, free thyroxine (FT4) and baseline TSH both were significant predictors of peak PRL. The average baseline FT4 concentration in alcoholic patients was significantly higher than that in healthy control subjects (n = 10). Our data, thus, suggest that small elevations of FT4 play a role in the inhibition of TSH and PRL responses to TRH among nondepressed, abstinent alcoholic patients.

Laparoscopy in General Surgery: The pros and cons of endoscopic surgery

After a period of rather slow initial acceptance by general surgeons, laparoscopy and video endoscopic surgery have suddenly burst on to the surgical scene. Almost overnight many of the surgical procedures once requiring a large incision are now being performed through small punctures. This article describes some of the more common procedures and discusses the merits and difficulties associated with these innovations.

Shared neuroendocrine patterns of post-traumatic stress disorder and alexithymia

High norepinephrine/cortisol ratios have been shown to be useful indicators of post-traumatic stress disorder (PTSD). Alexithymia can result from overwhelming stress; thus, we hypothesized that sympathetic-adrenal medullary/hypothalamic-pituitary adrenal ratios would be positively associated with alexithymia severity. In the present study, we correlated 3-methoxy-4-hydroxyphenylethylene glycol (MHPG)/adrenocorticotropic hormone (ACTH) and MHPG/cortisol ratios with self-report Toronto Alexithymia Scale (TAS) scores in a group (n = 17) of nondepressed, formerly alcohol-dependent men. The correlations between the respective ratios and TAS scores were 0.515 (p = 0.034) and 0.561 (p = 0.019). We suggest that increasing degrees of alexithymia are accompanied by an increasing separation of these two endocrine systems and then speculate that this dissociation has an anatomical basis in the lateralization of emotions.

Plate Tectonics and Hotspots: The Third Dimension

High-resolution seismic tomographic models of the upper mantle provide powerful new constraints on theories of plate tectonics and hotspots. Midocean ridges have extremely low seismic velocities to a depth of 100 kilometers. These low velocities imply partial melting. At greater depths, low-velocity and high-velocity anomalies record, respectively, previous positions of migrating ridges and trenches. Extensional, rifting, and hotspot regions have deep (> 200 kilometers) low-velocity anomalies. The upper mantle is characterized by vast domains of high temperature rather than small regions surrounding hotspots; the asthenosphere is not homogeneous or isothermal. Extensive magmatism requires a combination of hot upper mantle and suitable lithospheric conditions. High-velocity regions of the upper 200 kilometers of the mantle correlate with Archean cratons.

Diltiazem overdose: case report and review

We present a case of diltiazem overdose in which the patient ingested 4.2 grams in an apparent suicide attempt. He arrived in the emergency department two hours postingestion with a blood pressure of 60/40 torr and a heart rate of 62 beats/min in a junctional rhythm. Intervention included activated charcoal, gastric lavage, intravenous fluids, calcium (both chloride and gluconate), dopamine, and atropine with improvement in vital signs. Diltiazem levels were obtained and half-life calculated. This ingestion is one of the largest reported in the literature and is remarkable in that the patient recovered without pacing or other extraordinary measures. All eight previously published cases of diltiazem overdose, including all unpublished reports to the manufacturer, are reviewed and their management strategies examined. Successful treatment in which recovery has occurred in less than 48 hours, includes pressors, calcium, glucagon, pacing, and charcoal hemoperfusion. A strategy for emergency physicians to use when approaching this problem is suggested from the review.

Effects of target shape and neutron scattering on element sensitivities for neutron-capture prompt gamma-ray activation analysis

Results are presented for a study of the effects of neutron scattering by hydrogen on element sensitivities for in-beam neutron capture prompt gamma-ray activation analysis. In a scattering matrix, sensitivities vary as a function of both the scattering density, i.e., the number of scatters per unit volume and the magnitude of scattering cross sections, and the target geometry, i.e., the target shape and orientation with respect to the neutron beam. Element sensitivities (counts.s-1.mg-1) increased linearly with H density (g.mL-1) for H, B, Na, Cl, K, Mn, Br, Ag, Cd, I, Sm, and Gd, measured for liquids packaged in Teflon bags. Nine of the 12 elements studied had 1.69 +/- 0.18% sensitivity enhancement per percent increase in H density. Samarium sensitivity was enhanced by only 0.54 +/- 0.07%/% H, which may indicate that neutron scattering by H causes a shift in the energy distribution of the neutrons. Manganese sensitivity was enhanced by 2.44 +/- 0.26%/% H. The enhancement of the sensitivity for H itself varied with matrix composition. For several series of disk-shaped, solid, hydrogenous targets, element sensitivities increased with decreasing target thickness until, at some limiting thickness, this trend was reversed. Consistent with theory, sensitivities measured for spherical hydrogenous targets showed no enhancement.

Phylogenetic analysis and secondary structure of the Bacillus subtilis bacteriophage RNA required for DNA packaging

An unusual RNA molecule encoded by the Bacillus subtilis bacteriophage phi 29 is a structural component of the viral prohead and is required for the ATP-dependent packaging of DNA. Here we report a model of secondary structure for this prohead RNA developed from a phylogenetic analysis of the primary sequences of prohead RNAs of related phages. Twenty-nine phages related to phi 29 were found to produce prohead RNAs. These RNAs were analyzed by their ability to replace phi 29 RNA in in vitro phage assembly, by Northern blot hybridization with a probe complementary to phi 29 RNA, and by partial and complete sequence analyses. These analyses revealed four quite different sequences ranging in length from 161 to 174 residues. The secondary structure deduced from these sequences, in agreement with earlier observations, indicated that prohead RNA is organized into two domains. The larger 5'-domain (Domain I) is composed of 113-117 residues and contains four helices. Three of these helices appear to be organized into a central stem that is interrupted by two unpaired loops and the fourth helix and loop. The smaller 3'-domain (Domain II) is composed of 40-44 residues and consists of two helices. Domains I and II are separated by 8-13 unpaired residues. Nuclease cleavage occurs readily in this single-stranded joining region, and this cleavage allows the subsequent separation of the two RNA domains. The separated Domain I is fully active in DNA packaging in vitro. The functional significance and biological role of Domain II are unknown. The phylogenetic secondary structure model provides a basis for further analysis of the role of this RNA in bacteriophage morphogenesis.

Neutron capture prompt-gamma activation analysis of foods

The suitability of neutron capture prompt-gamma activation analysis (PGAA) for multielement analysis of foods was investigated. A total of 22 elements was observed in 40 food and mineral supplements. Hydrogen, B, C, N, Na, S, Cl, and K concentrations were determined in NIST RM 8431a Mixed Diet and in a wet diet composite made from FDA Total Diet Study collections. Because the neutron flux is so low for PGAA, the method is nondestructive and reanalysis of analytical portions is possible. Both diet materials were analyzed before and after freeze-drying to check for element losses during this process. No losses were found for RM 8431a, but significant losses of B and Na were observed for the wet composite. The measured loss of hydrogen for the wet composite was not consistent with the assumption that the lost mass was water only.

Giant fibrovascular polyps of the esophagus

A 77-yr-old man with chest discomfort and progressive dysphagia was found to have an intraluminal esophageal lesion of remarkable size. A giant fibrovascular polyp (11 x 7 x 3.5 cm) was successfully removed surgically by a transcervical approach. This unusual benign esophageal lesion is discussed in terms of classification and clinical presentation from a historical perspective. Particular attention is focused on the current approach to diagnosis and management. Endoscopic ultrasonography was employed as part of the evaluation.

Cholera toxin inhibits resting human T cell activation via a cAMP-independent pathway

The catalytic subunit of cholera toxin (CT) can chemically modify the alpha polypeptides of certain G-binding proteins and thus alter their function. In order to study the involvement of CT-sensitive G proteins in T cell activation, we have utilized CT in an in vitro system in which purified, resting human peripheral T cells are activated by anti-CD3 antibodies and rIL-2. Perturbation of the TCR/CD3 molecular complex by anti-CD3 antibodies causes changes in membrane phospholipids and induces a rise in cytoplasmic Ca2+. These events, however, are insufficient to allow progression into cellular proliferation and addition of IL-2 is required. Under these conditions, treatment of cells with a low concentration of CT (2 ng/ml) causes a significant inhibition of the anti-CD3-induced calcium event as well as the anti-CD3 plus IL-2-stimulated proliferation. Under our experimental conditions, inhibition of both proliferation and intracellular Ca2+ elevation by CT requires the involvement of the TCR/CD3 complex. This is supported by the observation that the toxin does not inhibit either the proliferation triggered by ionomycin and PMA or the Ca2+ influx induced by the ionophore. These data suggest that in TCR/CD3-mediated T cell activation CT acts at a point between TCR/CD3 perturbation and the generation of intracellular Ca2+. In view of the ability of CT to activate the alpha subunit of the G protein that stimulates adenyl cyclase (G alpha s), it is possible that the effect of CT on T cells is secondary to intracellular elevation of cAMP. However, measurement of cAMP levels both early after CT addition and at later time points, when proliferation is maximal, reveals lack of cyclic nucleotide accumulation. The presented data are consistent with the interpretation that the CT-mediated inhibition is caused by the modification of a G-binding protein that is either directly or indirectly associated with triggering of T cells via the TCR/CD3 molecular complex. The data also suggest that this protein is not G alpha s and it probably represents an as yet unidentified moiety or one of the several G proteins that have been recently described as regulators of phospholipase C activation.

Cholera toxin inhibits resting human T cell activation via a cAMP-independent pathway

The catalytic subunit of cholera toxin (CT) can chemically modify the alpha polypeptides of certain G-binding proteins and thus alter their function. In order to study the involvement of CT-sensitive G proteins in T cell activation, we have utilized CT in an in vitro system in which purified, resting human peripheral T cells are activated by anti-CD3 antibodies and rIL-2. Perturbation of the TCR/CD3 molecular complex by anti-CD3 antibodies causes changes in membrane phospholipids and induces a rise in cytoplasmic Ca2+. These events, however, are insufficient to allow progression into cellular proliferation and addition of IL-2 is required. Under these conditions, treatment of cells with a low concentration of CT (2 ng/ml) causes a significant inhibition of the anti-CD3-induced calcium event as well as the anti-CD3 plus IL-2-stimulated proliferation. Under our experimental conditions, inhibition of both proliferation and intracellular Ca2+ elevation by CT requires the involvement of the TCR/CD3 complex. This is supported by the observation that the toxin does not inhibit either the proliferation triggered by ionomycin and PMA or the Ca2+ influx induced by the ionophore. These data suggest that in TCR/CD3-mediated T cell activation CT acts at a point between TCR/CD3 perturbation and the generation of intracellular Ca2+. In view of the ability of CT to activate the alpha subunit of the G protein that stimulates adenyl cyclase (G alpha s), it is possible that the effect of CT on T cells is secondary to intracellular elevation of cAMP. However, measurement of cAMP levels both early after CT addition and at later time points, when proliferation is maximal, reveals lack of cyclic nucleotide accumulation. The presented data are consistent with the interpretation that the CT-mediated inhibition is caused by the modification of a G-binding protein that is either directly or indirectly associated with triggering of T cells via the TCR/CD3 molecular complex. The data also suggest that this protein is not G alpha s and it probably represents an as yet unidentified moiety or one of the several G proteins that have been recently described as regulators of phospholipase C activation.