The nephrotoxicity for mice of deisopropylngaione, a minor furanoid component of toxic myoporaceous essential oils

Deisopropylngaione (DIN) is one of a family of hepatotoxic furanosesquiterpenoid essential oils which is found in small amounts (5%) in the leaves of some specimens of the Australian plant Myoporum deserti. DIN differs from other furanoid myoporaceous essential oils in that it also causes lesions in the lungs and kidneys. At the near LD50 dose rate of 150 mg kg-1 given by intraperitoneal injection, DIN is able to cause lethal renal proximal tubular necrosis without causing significant injury to the liver and lungs in adult male mice. Following dosing, there is an increase in kidney weight due mainly to increase in water content which reaches a maximum within 16-24 h. This is accompanied by degeneration and necrosis of the proximal tubular epithelium, with proteinuria and glucosuria lasting up to 9 days in non-lethally affected mice. Marked body weight loss due to the intoxication causes a marked increase in the kidney weight:body weight ratio lasting between 9 and 18 days. Residual lesions are still present in the kidneys at 32 days, but recovery is eventually complete. DIN is structurally similar to the sweet potato toxic furan 4-ipomeanol and, like the latter, is probably injurious to the kidneys through toxic metabolism by the cytochrome-P450-containing monooxygenases of the proximal tubular epithelium. Although slight renal injury is occasionally observed in livestock poisoned by myoporaceous plants, it is unlikely that DIN is the cause. So far, DIN, like 4-ipomeanol, appears to be unequivocally nephrotoxic only for the male mouse.

Salvage procedures in failed hip arthroplasties

Results and observations based on a series of 90 patients who underwent revision hip arthroplasty are reported, including engineering notes on the removal of cement within the femur and assessment of the mechanisms of failure of the original arthroplasties. The authors state a preference for performing revision in two stages, and leaving original cement in the bottom of the femoral canal.

Polar transport of 45Ca2+ across the elongation zone of gravistimulated roots

The movement of calcium across the elongation zone of gravistimulated primary roots of maize (Zea mays L.) was measured using 45Ca2+. Radioactive calcium was applied to one side of the elongation zone about 4 mm back from the root tip and the distribution of radioactivity across the root in the region of application was determined using scintillation spectrometry. The movement of 45Ca2+ across the elongation zone was non-polar in vertically oriented roots. In gravistimulated roots the movement of label was polarized with about twice as much label moving from top to bottom as from bottom to top. A variety of treatments which interfere with gravitropism was found to eliminate the polar movement of 45Ca2+ across the elongation zone. In maize cultivars which require light for gravitropic competency, dark grown roots exhibited neither gravitropism nor polar movement of 45Ca2+ across the elongation zone. Upon illumination the roots developed but gravitropic competency and gravity-induced polar movement of 45Ca2+ across the elongation zone. Similarly, roots of light-grown seedlings lost both gravitropic competency and 45Ca2+ transport polarity upon transfer to the dark. The results indicate a close correlation between calcium movement and gravitropism in primary roots in maize.

Polar transport of auxin across gravistimulated roots of maize and its enhancement by calcium

The effect of Ca on the polar movement of [3H]indoleacetic acid ([3H]IAA) in gravistimulated roots was examined using 3-day-old seedlings of maize (Zea mays L.). Transport of label was measured by placing an agar donor block containing [3H]IAA on one side of the elongation zone and measuring movement of label across the root into an agar receiver block on the opposite side. In vertically oriented roots, movement of label across the elongation zone into the receiver was slight and was not enhanced by incorporating 10 millimolar CaCl2 into the receiver block. In horizontally oriented roots, movement of label across the root was readily detectable and movement to a receiver on the bottom was about 3-fold greater than movement in the opposite direction. This polarity was abolished in roots from which the caps were removed prior to gravistimulation. When CaCl2 was incorporated into the receivers, movement of label across horizontally oriented intact roots was increased about 3-fold in both the downward and upward direction. The ability of Ca to enhance the movement of label from [3H]IAA increased with increasing Ca concentration in the receiver up to 5 to 10 millimolar CaCl2. With the inclusion of CaCl2 in the receiver blocks, gravity-induced polar movement of label into receiver blocks from applied [3H]IAA was detectable within 30 minutes, and asymmetric distribution of label within the tissue was detectable within 20 minutes. The results indicate that gravistimulation induces a physiological asymmetry in the auxin transport system of maize roots and that Ca increases the total transport of auxin across the root.

Structure and chromosomal arrangement of leghemoglobin genes in kidney bean suggest divergence in soybean leghemoglobin gene loci following tetraploidization

We have determined the structure of one of the leghemoglobin (Lb) genes of Phaseolus vulgaris (kidney bean) and deduced the chromosomal arrangement of leghemoglobin genes by genomic hybridizations with Lb and two other sequences, each specific to the 5' or 3' region of the soybean leghemoglobin loci. By comparing this organization with two other species of legumes, Glycine max (soybean) and G. soja (wild soybean), a phylogeny of leghemoglobin gene loci was traced. The intragenic structure of the kidney bean leghemoglobin gene shows the same intron/exon arrangement as that of soybean leghemoglobin genes and extensive sequence homologies in both coding as well as 5' and 3' non-coding regions. The presence in the kidney bean genome of four leghemoglobin genes suggests that tandem duplications of a single primordial plant globin gene had occurred to generate four leghemoglobin genes in an ;Lb-locus' before Glycine and Phaseolus species diverged. Chromosome duplication by tetraploidization in Glycine generated two loci containing four genes each. A large deletion in one of the two four-gene loci in soybean resulted in the generation of the Lbc(2) locus containing two leghemoglobin genes, one functional and another pseudo (LbPsi(2)). This pseudogene, unlike that present on the main locus, is represented by only two and a half exons and appears to be truncated. The two other truncated genes (LbT(1) and LbT(2)) were probably generated similarly in the genome of Glycine spp. following tetraploidization before the divergence of G. max and G. soja.

Pneumoconiosis and exposures of dental laboratory technicians

One hundred and seventy-eight dental laboratory technicians and 69 non-exposed controls participated in an epidemiological respiratory study. Eight technicians who had a mean of 28 years' grinding nonprecious metal alloys were diagnosed as having a simple pneumoconiosis by chest radiograph. Mean values for per cent predicted FVC and FEV1 were reduced among male nonsmoker technicians compared to male nonsmoker controls; after controlling for age, there was also a reduction in spirometry with increasing work-years. An industrial hygiene survey was conducted in 13 laboratories randomly selected from 42 laboratories stratified by size and type of operation in the Salt Lake City, Utah metropolitan area. Personal exposures to beryllium and cobalt exceeded the Threshold Limit Values (TLVs) in one laboratory. Occupational exposures in dental laboratories need to be controlled to prevent beryllium-related lung disorders as well as simple pneumoconiosis.

Left-handed "Z" DNA antibodies in rheumatoid arthritis and systemic lupus erythematosus

A solid phase radioimmunoassay was used to evaluate antibodies to 13 nucleic acid antigens for their ability to distinguish between systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and control sera. The antigens included 5 synthetic duplex DNA, several single-stranded nucleic acids and 2 left-handed "Z" DNA. Many of the 45 SLE patients' sera showed distinctive patterns of binding to the various antigens, but this could not be correlated with disease type or activity. In general, the duplex DNA antigens gave the best sensitivity and specificity for the detection of SLE but the antigen poly(dA) may be superior. Antibodies to "Z" DNA were found in some SLE patients but surprisingly, the binding was significantly higher in the RA group than in the SLE group. This is the first nucleic acid antigen to show more specificity for RA than for SLE.

Intraluminal distension pressure on intestinal lymph flow, serosal transudation and fluid transport in the rat

Effect of distension pressure (d.p.) on the rate of lymph flow, serosal transudation and fluid transport was studied on an in vivo upper jejunal preparation. In the non-absorptive state with isotonic Na2SO4 solution as the luminal fluid, neither lymph flow nor transudation was increased with increasing d.p. from 0 to 3, 10, 20, 40 or 70 mmHg. Fluid absorption rate (Jv) increased by more than 100% when d.p. was increased from 0 to 3 mmHg whether glucose was present or absent in the luminal fluid (Krebs-Ringer solution). In the presence of glucose, there was no difference in Jv in the range of d.p. between 3 and 70 mmHg. In the absence of glucose Jv decreased when d.p. was above 10 mmHg. Whether with or without glucose, lymph flow did not change between d.p. of 0 and 10 mmHg but decreased at higher pressures. Whether with or without glucose, transudation began to appear at d.p. of 10 mmHg, increased with increasing d.p. up to 70 mmHg, but was much less in the absence of glucose. Protein concentration in the lymph (1.5-2.4% (w/v] and transudation (1.5-2.1% (w/v] was practically the same, suggesting that the latter could have originated from the lymph which leaked out of the serosal membrane. Blood flow in the subserosal capillaries and venules was remarkably reduced when d.p. was above 10 mmHg. In both jejunum and ileum, d.p. never caused fluid secretion during distension but resulted in transient fluid secretion as well as transudation following distension, apparently due to increased capillary filtration as a result of increased capillary permeability by ischaemia (during distension). From the effect of d.p. on the increase of transudation, presumably lymph, it is concluded that luminal hydrostatic pressure may play a role in fluid transport via the lymphatic system.

Poly(pyrimidine) . poly(purine) synthetic DNAs containing 5-methylcytosine form stable triplexes at neutral pH

Poly(pyrimidine) . poly(purine) tracts have been discovered in the 5'-flanking regions of many eucaryotic genes. They may be involved in the regulation of expression since they can be mapped to the nuclease-sensitive sites of active chromatin. We have found that poly(pyrimidine) . poly(purine) DNAs which contain 5-methylcytosine (e.g. poly[d(Tm5C)] . poly[d(GA)]) will form a triplex at a pH below 8. In contrast, the unmethylated analogue, poly[d(TC)] . poly[d(GA)] only forms a triplex at pHs below 6. Synthetic DNAs containing repeating trinucleotides and poly[d(Um5C)] . poly[d(GA)] behave in a similar manner. Thus the stability of a triplex can be controlled by methylation of cytosine. This suggests a model for the regulation of expression based upon specific triplex formation on the 5'-side of eucaryotic genes.

Preliminary crystallographic data for a monoclonal Fab fragment specific for HPr of the phosphoenolpyruvate: sugar phosphotransferase system of Escherichia coli

Crystals for Fab fragments from a monoclonal antibody to HPr of the phosphoenopyruvate:sugar phosphotransferase system of Escherichia coli have been obtained from 14% polyethylene glycol 6000, 5 mM-Tris X HCl, 50 mM-sodium phosphate and 0.2 M-sodium chloride at pH 8.0. The space group is P2(1) with a = 110.85 A, b = 66.18 A, c = 67.21 A, beta = 113.0 degrees and Z = 4. The crystals exhibit the forms [100], [011] and [011] and the solvent content is 47%.

Monoclonal antibodies specific for poly(dG) X poly(dC) and poly(dG) X poly(dm5C)

Most duplex DNAs that are in the "B" conformation are not immunogenic. One important exception is poly(dG) X poly(dC), which produces a good immune response even though, by many criteria, it adopts a conventional right-handed helix. In order to investigate what features are being recognized, monoclonal antibodies were prepared against poly(dG) X poly(dC) and the related polymer poly(dG) X poly(dm5C). Jel 72, which is an immunoglobulin G, binds only to poly(dG) X poly(dC), while Jel 68, which is an immunoglobulin M, binds approximately 10-fold more strongly to poly(dG) X poly(dm5C) than to poly(dG) X poly(dC). For both antibodies, no significant interaction could be detected with any other synthetic DNA duplexes including poly[d(Gm5C)] X poly[d(Gm5C)] in both the "B" and "Z" forms, poly[d(Tm5Cm5C)] X poly[d(GGA)], and poly[d(TCC)] X poly[d(GGA)], poly(dI) X poly(dC), or poly(dI) X poly(dm5C). The binding to poly(dG) X poly(dC) was inhibited by ethidium and by disruption of the DNA duplex, confirming that the antibodies were not recognizing single-stranded or multistranded structures. Furthermore, Jel 68 binds significantly to phage XP-12 DNA, which contains only m5C residues and will precipitate this DNA in the absence of a second antibody. The results suggest that (dG)n X (dm5C)n sequences in natural DNA exist in recognizably distinct conformations.

The mixing and axial transport of smoke in oscillatory tube flows

To gain a better insight on the mechanisms of transport in high-frequency ventilation, we examined the transport of smoke in a straight tube, a model of the trachea. A smoke bolus was injected into a ventilator, and the movement of the smoke along the tube was monitored by a laser-photomultiplier system. With this system we studied the instantaneous movement of the smoke cycle by cycle and that over a longer period. From the latter, a transport coefficient can be calculated to characterize how fast the smoke is transported along the tube. We found that for low frequency, the flow is laminar with a transport coefficient smaller or approximately 700 cm2/s. For very high frequencies, the oscillatory flow becomes turbulent and effects a strong radial and axial mixing. The transport coefficient increases to as high as 5,000 cm2/s. Over a certain intermediate range of the frequency, the mixing can be a laminar one over several cycles of oscillation and a turbulent one for some subsequent cycles.

The lithium loading dose method in a clinical setting

The lithium loading dose method developed by Cooper and associates resulted in achievement of therapeutic concentrations in 29 of 30 psychiatric inpatients. Fewer lithium determinations were required than in 30 other inpatients treated with the traditional trial-and-error technique.

Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors

Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism. In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side. Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip. Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip. The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature.

Hepatic lymph flow and protein concentration during intravenous saline infusion and intestinal fluid absorption

A simple procedure for the collection of the postnodal and prenodal hepatic lymph in the rats under pentobarbital anesthesia is described. Lymph flow (JL) from the main hepatic lymph duct ( postnodal ), protein concentration in both the lymph (CL) and plasma (CP), and the CL/CP ratio were 0.22 +/- 0.1 ml/kg of body weight . hr (0.66 +/- 0.3 ml/100 g wet liver wt . hr), 4.3 +/- 0.5 and 6.2 +/- 0.3 g%, and 0.69 +/- 0.1 (mean +/- SE), respectively. There was no significant difference in CL between prenodal and postnodal lymph in the fasted or unfasted rats. During intestinal fluid absorption with an increase in intestinal JL, postnodal hepatic JL or CL did not change. During intravenous saline infusion with lowering of plasma oncotic pressure, there was a small increase in prenodal JL (by approximately 160%) with some decrease (by 16%) in CL/CP ratio but a much larger increase in postnodal JL (by approximately 700%) with a significant decrease (by 55%) in CL/CP ratio. The results demonstrate that both flow and protein concentration of the postnodal lymph differ greatly from that of the prenodal lymph due to modification during transit through the lymph node. The small increase of the prenodal JL with negligible change in CL/CP ratio during saline infusion suggests that oncotic pressure grandient plays a minor or insignificant role in the transsinusoidal fluid transport in the liver.

Functional groups on 'Z' DNA recognized by monoclonal antibodies

Both brominated poly[d(GC)] and poly[d( Gm5C )] form stable left-handed Z-DNA structures at physiological ionic strengths. These two antigens were used to prepare monoclonal antibodies from immunized mice. The specificity of the antibodies was studied in detail with a solid-phase radioimmune assay as well as by means of competition experiments. Both immunogens produced several relatively non-specific antibodies but two types of very specific antibody were also distinguished. The first binds poly[d( Gm5C )] but not brominated poly[d(GC)] while the other has the opposite specificity and will only bind the brominated polymer.

Zinc deficiency and the development of esophageal and forestomach tumors in Sprague-Dawley rats fed precursors of N-nitroso-N-benzylmethylamine

Nine-week-old zinc-sufficient (100 mg zinc/kg feed) and zinc-deficient (7 mg zinc/kg feed) noninbred male Sprague-Dawley rats were given free access 5 days a week to deionized drinking water containing low (0.05%) or high (0.25%) quantities of benzylmethylamine (BMA) and concurrently 0.5% NaNO2. In contrast to the action of the preformed carcinogen N-nitroso-N-benzylmethylamine, which almost invariably produced esophageal tumors, oral administration of its precursors, BMA and NaNO2, resulted in forestomach tumors as well. In both the high- and low-BMA groups given precursors for 16 weeks, the incidence of papillomas in both the esophagus and forestomach was significantly higher in the zinc-deficient than in the zinc-sufficient rats, but zinc deficiency did not significantly increase the yield of forestomach carcinomas. However, when combined high BMA and NaNO2 administration was prolonged to 37 weeks, the yield of forestomach carcinomas was significantly greater in the zinc-deficient than in the zinc-sufficient animals. Because endogenous synthesis of N-nitrosamines from ingested precursors is an important source of human exposure to these carcinogenic compounds and because dietary zinc deficiency might be operating in some areas with a high incidence of esophageal cancer, our data are of more than routine significance.

The evolution of a plant globin gene family

We have analyzed the sequences of soybean leghemoglobin genes as an initial step toward understanding their mode of evolution. Alignment of the sequences of plant globin genes with those of animals reveals that based on the proportion of nucleotide substitutions that have occurred at the first, second, and third codon positions, the time of divergence of plant and animal globin gene families appears to be extremely remote (between 900 million and 1.4 billion years ago, if one assumes constancy of evolutionary rate in both the plant and animal lineages) and in addition to the normal regulatory sequences on the 5' end, an approximately 30-base-pair sequence, specific to globin genes, that surrounds the cap site is conserved between the plant and animal globin genes. Comparison of the leghemoglobin sequences with one another shows that the relative amount of sequence divergence in various coding and noncoding regions is roughly similar to that found for animal globin genes and as in animal globin genes, the positions of insertions and deletions in the intervening sequences often coincide with the locations of direct repeats. Thus, the mode of evolution of the plant globin genes appears to resemble, in many ways, that of their animal counterparts. We contrast the overall intergenic organization of the plant globin genes with that of animal genes, and discuss the possibility of the concerted evolution of the leghemoglobin genes.

Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors

Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism. In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side. Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip. Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip. The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature.

Relationship between intestinal motility, tone, water absorption and lymph flow in the rat

The relations between motility, tone, water absorption rate (Jv) and lymph flow (J1), were studied in an exteriorized upper jejunal preparation in vivo, with its serosal side bathed in Krebs-Ringer or other solutions. Neither Jv nor J1 was correlated with motility. When the luminal fluid consisted of an isotonic solution of MgSO4, glucose or LiCl, motility was greatly increased with no increase in J1. When the serosal fluid consisted of an isotonic solution of mannitol, glucose or MgSO4, motility was depressed with a large decrease in tone, and Jv was increased by 51-83% with a decrease in J1. When the serosal fluid consisted of an isotonic solution of NaCl, Na2SO4, LiCl or KCl, motility was decreased with either no change or an increase in tone, and both Jv and J1 were much decreased. When isotonic choline Cl solution was employed as the serosal fluid, motility increased with an increase in tone, Jv became negative (fluid secretion), and J1 decreased to 0. Acetylcholine depressed motility but increased tone with a decrease in Jv and J1. Eserine increased both tone and motility with a decrease in Jv and J1. Serotonin caused no change in motility but increased tone with a decrease in Jv and J1. Noradrenaline and adrenaline depressed motility and reduced tone with an increase in Jv and J1. Isoprenaline abolished motility and reduced tone with a large increase in Jv but no change in J1. Pentobarbitone depressed motility and reduced tone with an increase in Jv but a decrease in J1. It is concluded that the intestine responds to various stimuli with a change in motility, or tone, or both. Intestinal motility per se does not produce lymph. Since an increase or decrease in tone always results in a decrease or increase in Jv, respectively, regardless of the nature of the conditions, a relaxation of the intestinal musculature appears to be associated with an increase in water absorption.

Gravity-Induced Polar Transport of Calcium across Root Tips of Maize

Calcium movement across primary roots of maize (Zea mays, L.) was determined by application of (45)Ca(2+) to one side of the root and collection of radioactivity in an agar receiver block on the opposite side. Ca movement across the root tip was found to be at least 20 times greater than movement across the elongation zone. The rapid movement of Ca across the tip was severely inhibited in roots from which the root cap had been removed. Ca movement across the tip was also strongly retarded in roots pretreated with 2,4-dinitrophenol or potassium cyanide. Orientation of roots horizontally had no effect on Ca movement across the elongation zone but caused a strong asymmetry in the pattern of Ca movement across the tip. In gravistimulated roots, the movement of Ca from top to bottom increased while movement from bottom to top decreased. The data indicate that gravistimulation induces polar movement of Ca toward the lower side of the root cap. An earlier report (Lee, Mulkey, Evans 1983 Science 220: 1375-1376) from this laboratory showed that artificial establishment of calcium gradients at the root tip can cause gravitropic-like curvature. Together, the two studies indicate that Ca plays a key role in linking gravistimulation to the gravitropic growth response in roots.

Molecular analysis of the HLA-D region genes

Analysis of the amino acid sequence of the HLA-DR alpha chain and the structure of the gene encoding it have shown strong homologies to membrane proximal domains of the DR beta chain and HLA-ABC, as well as to beta 2-microglobulin. Weaker, but nevertheless apparent homologies to C kappa and C lambda immunoglobulin domains support the interpretation that these genes diverged in evolution from a primordial immunoglobulin-like domain. Cosmid clones containing sequences related to the DR alpha chain have been isolated. These sequences probably represent the SB and DC alpha genes. In addition to the alpha "genes," some of the cosmids also contain sequences related to the DR beta chain suggesting that the human HLA-D region alpha and beta genes are interspersed.

Chromosomal arrangement of leghemoglobin genes in soybean

A cluster of four different leghemoglobin (Lb) genes was isolated from AluI-HaeIII and EcoRI genomic libraries of soybean in a set of overlapping clones which together include 45 kilobases (kb) of contiguous DNA. These four genes, including a pseudogene, are present in the same orientation and are arranged in the order: 5'-Lba-Lbc1-Lb psi-Lbc3-3'. The intergenic regions average 2.5 kb. In addition to this main Lb locus, there are other Lb genes which do not appear to be contiguous to this locus. A sequence probably common to the 3' region of Lb loci was found flanking the Lbc3 gene. The 3' flanking region of the main Lb locus also contains a sequence that appears to be expressed more abundantly in root tissue. Another sequence which is primarily expressed in root and leaf is found 5' to two Lb loci. Overall, the main leghemoglobin locus is similar in structure to the mammalian globin gene loci.

The complete nucleotide sequence of the I-E alpha d immune response gene

We have isolated and sequenced the complete murine I-E alpha immune response gene of the H-2db haplotype. The I-E alpha d gene consists of 5300 basepairs and is organized into five or possibly six exons that correspond to different domains of the alpha chain. The amino acid sequence deduced from the I-E alpha gene shows 75% homology to its human counterpart, the HLA-DR alpha chain. The absence of I-E antigen in H-2 mice is due to lack of E alpha chain synthesis. We show here that this defect is caused by a deletion in the 5' end of the I-E alpha b gene.

Characterization of monoclonal antibodies specific for isopentenyl adenosine derivatives occurring in transfer RNA

A family of isopentenyl adenosine derivatives are naturally occurring components of transfer RNA and are involved in several different functional roles in the cell. To facilitate the study of the biochemistry of these modified nucleosides we have raised monoclonal antibodies to N6-(delta 2-isopentenyl)adenosine and N6-(4-hydroxy-3-methyl-but-2-enyl)adenosine. The antibodies show considerable specificity and three characteristic types are distinguishable. The first type have the hydroxylated derivative as the preferred antigen, the second type have isopentenyl adenosine as the preferred antigen and a third type show a specificity for all isopentenyl-containing derivatives.

Intestinal transudation, secretion, and lymph flow during volume expansion in the rat

The effect of volume expansion by intravenous infusion of saline on the rate of intestinal lymph flow (JL), serosal surface transudation (JT), and secretion (JS) from upper jejunum was determined. During saline infusion there was a large increase in JS and JT but a small increase in JL due to increased capillary filtration. About 20% of JL from the main intestinal lymph duct originated from the intestine and the rest from the mesenteric pedicle. JL (corrected for pedicle lymph flow), JT, and JS were estimated to account for 10, 30, and 60% of capillary filtrate from the intestine, respectively. Neither lymph nor secretion contained measurable protein, but transudation had a high protein concentration about half of that in the plasma. From these findings it is inferred that probably both JL and JS were derived from the capillary filtrate of mucosa and submucosa vascular beds and JT from that of muscular vascular bed and that capillaries and venules in the mucosa restricted the passage of protein molecules while those of the intestinal muscular tissue were highly permeable to protein.

Intravenous access: a comparison of two methods

The reliability in providing a continued venous route to the circulation is compared between a winged needle (Abbott "Butterfly--23 INT") and a plastic catheter (Jelco Teflon "Catheter Placement Unit", 22 gauge). The catheter remained within the vein in all cases and had a much lower incidence of total obstruction during the study period. Where an intravenous infusion is not in place, a plastic catheter provides a more reliable access route to the circulation than does a winged needle.

Effects of stretching and stirring on water and glucose absorption by canine mucosal membrane

A 'mini' canine mucosal membrane preparation permitting simultaneous determination of water (Jv) and glucose (Jg) absorption rates, microscopic examination or micropuncture of the villi was used in this study. The small membranes were more stretched than the large ones, with more than a one-fold increase in both Jv and Jg, apparently due to a change in architectural orientation between the villi and subvillous supporting tissue so as to facilitate water transport via the lymphatic system. During stirring of the bathing solution, the villi in the small membranes were widely separated from each other with more to-and-fro swaying movements than in the large ones. Stirring was seen to cause up-and-down movements of the loosely suspended large membranes but not the small ones. In the small membranes stirring caused no change in Jv but an increase in Jg due to the increase in glucose concentration in the absorbate, while in the large membranes both Jv and Jg were greatly increased. It is thus considered that the increase in absorption in the large membranes caused by stirring is mainly due to the increased membrane movements promoting lymph flow.

Potassium Sorbate Inhibition of Microorganisms Isolated from Seafood 1

Microorganisms isolated from seafood showed various degrees of sensitivity toward potassium sorbate (PS). At pH 7.0, PS concentration of 0.53% completely inhibited growth of Moraxella sp., while 2.73% was needed to inhibit Arthrobacter sp. Pseudomonas I sp., which was relatively resistant to PS (inhibitory concentration = 1.62%), was not affected by 0.3% PS after freeze-thaw treatment (-78°C for 8 min and 20°C for 20 min), but showed a delay in onset of logarithmic growth for up to 20 h after heating at 50°C for 5 min. The inhibitory effect of PS on sub-lethally injured Pseudomonas I was greater in basal medium (Minimum Broth, Davis) than in a rich medium (tryptone-peptone-extract, TPE). Alteromonas putrefaciens , which was sensitive to PS (inhibitory concentration = 0.74%), was also sensitive to freeze-thaw and mild heat. The lag period for quick-frozen cells was extended by 14 h in the presence of 0.05% PS. Heating at 45°C for 10 sec was sufficient to cause complete inhibition of growth by 0.05% PS in MBD, and 8 h delay in the onset of logarithmic growth in TPE. Selective and inhibitory effects of PS, therefore, could be further enhanced in frozen or heat-treated seafood.

Novel aspects of the structure of the Escherichia coli nucleoid investigated by a rapid sedimentation assay

The Escherichia coli nucleoid is maintained in its folded highly condensed state by constraints which involve RNA and protein. We have developed a rapid sedimentation assay to determine the state of folding of the membrane-free nucleoid. An approximate measure of the stability of the nucleoids under various conditions can then be estimated by measuring the temperature at which the nucleoids unfold. Using ethidium and gamma irradiation (which removes the negative supercoiling of the native nucleoid) as probes, it can be shown that there are two types of constraint involved in the condensation of the nucleoid. One of these constraints is destabilized by ethidium but stabilized by negative supercoiling; the second constraint is unaffected by both ethidium and negative supercoiling. Several models can be proposed: (i) a DNA . RNA duplex, (ii) a double-strand DNA (dsDNA) . RNA triplex, (iii) DNA-protein interactions, (iv) a topological knot with RNA, and (v) a DNA tetraplex. The topological knot model is not consistent with the data and many combinations of the others can be excluded. If RNA is involved in both constraints then RNA . DNA duplexes and dsDNA . RNA triplexes are involved in stabilizing the nucleoid.

Specificity of autoimmune monoclonal Fab fragments binding to single-stranded deoxyribonucleic acid

Fab fragments from hybridoma HEd 10 [Lee, J. S., Lewis, J.R., Morgan, A.R., Mosmann, T.R., & Singh, B. (1981) Nucleic Acids Res. 9, 1707-1721] were prepared in large amounts by papain digestion of the immunoglobulin G (IgG) fraction from ascites fluid. Binding data were generated by a fluorescence quenching technique, and binding constants [K(0)] were estimated from Scatchard plots. The Fab fragments bound tightly to poly(dT) [K(0) = 12.7 X 10(6) M-1], and analysis of binding constants for the series p(dT)2 to p(dT)17 showed that the recognition sequence consisted of four consecutive residues. The effect of ionic strength on the interaction suggested that only two phosphates were involved. Binding constants for poly(dU), poly[d(brU)], poly[d(brC)], and poly(rU) were 1.0 X 10(6) M-1, 18.8 X 10(6) M-1, 0.5 X 10(6) M-1, and less than 0.5 X 10(6) M-1, respectively, implicating the involvement of the 3, 4, and 5 positions of the pyrimidine ring as well as the deoxyribose sugar in the recognition process. At high ionic strength (0.5 M) K(0) for whole IgG binding to poly(dT) was 75 X 10(6) M-1 compared to a value of 1.1 X 10(6) M-1 for the Fab fragment. These results may have implications for the tissue damage caused by DNA-containing immune complexes in systemic lupus erythematosus.

Molecular mechanisms of binding and single-strand scission of deoxyribonucleic acid by the antitumor antibiotics saframycins A and C

The quinone antitumor antibiotics saframycins A and C bind to duplex DNA and G,C containing complementary oligodeoxyribonucleotides at pHs below 5.5 via selective protonation of the antibiotics at the N-12 positions in an equilibrium process. This binding shows minor groove specificity to T4 DNA for both antibiotics. Saframycin A exhibits an additional mode of covalent binding to DNA, which is reversible by heating, via an animal linkage with the NH2 group of guanine. Covalent binding of saframycin A is enhanced by prior reduction of the quinone moiety via a different mechanism with concomitant elimination of the nitrile group and plausibly involves an intermediate quinone methide. Both saframycin A and saframycin C when reduced in situ with NADPH or sodium borohydride cause single-strand breaks, but not double-strand breaks, in PM2 covalently closer circular DNA. This latter reaction proceeds via intermediate semiquinones, the identity and conformation of which are established by EPR. The DNA scission process which requires oxygen is mediated by the generation of O2-., H2O2 and OH., the latter of which species was identified by spin trapping. The strand scission of DNA is pH dependent and, unlike the binding of the antibiotics, is strongly inhibited by Mg2+ and Zn2+ ions.

Evidence for an internal promoter preceding tufA in the str operon of Escherichia coli

We constructed plasmids carrying tufA from which the major promoter for the rpsL-rpsG-fus-tufA operon (also called the str operon) had been removed. These plasmids continued to express tufA, as judged by the ability to complement mocimycin resistance and by electrophoretic analysis of synthesized proteins. Tn5 transpositions into fus, the gene for elongation factor G, which lies immediately on the 5' side of tufA, failed to obstruct the expression of tufA. The subcloning of a 2,000-base-pair PstI-SmaI DNA fragment (containing the intercistronic region between tufA and fus, the distal portion of fus, and the proximal portion of tufA) next to promoterless tetracycline resistance genes (tet) yielded a plasmid that was capable of bestowing resistance to 12 microgram of tetracycline per ml. The removal of an EcoRI fragment that lies within fus destroyed the ability of the 2,000-base-pair PstI-SmaI fragment to promote the transcription of tet. These data indicate that, in addition to the operon's major promoter rpsLp, there is an internal promoter, tufAp, which can be used for the transcription of tufA, tufAp probably lies within fus, about 50 base pairs upstream from its 3' end and 120 base pairs from the start codon of tufA. The relative activities of tufB and of tufA-from-tufAp were estimated by a comparison of beta-galactosidase activities of almost identical EF-Tu-beta-galactosidase protein fusions; they were approximately equal.

Immunoelectron microscopic identification of Langerhans cells using a new antigenic marker

The specificity of a monoclonal antibody (OKT6) for epidermal Langerhans cells was examined by immunoelectron microscopy. Peroxidase-labeled OKT6 bound to 1-5% of suspended human epidermal cells, as determined by light microscopy. Electron microscopic examination of peroxidase-labeled cells revealed that all Birbeck granule-containing Langerhans cells bound OKT6. In addition, a small population of indeterminate cells, lacking the Birbeck granule, was also labeled with OKT6. The ultrastructural studies confirm the specificity of OKT6 for Langerhans cells and suggest that the indeterminate cell represents a related cell population.

Scleral melanocytoma

An 81-year-old black woman with severe rheumatoid arthritis presented with an enlarging black lesion on the medial sclera of the left eye. Scleromalacia perforans was suspected. At surgical exploration, a deeply pigmented tumor was encountered, with extension into the orbit, along the medial rectus muscle. Biopsy revealed a benign melanocytoma.

A method for the specific inhibition of poly[d(A-T)] synthesis using the A-T specific quinoxaline antibiotic TANDEM

A serious problem in the replication of repeating-sequence DNa polymers using Escherichia coli DNA polymerase I arises from the fact that this polymerase has a very strong preference for the replication of poly[d(A-T)]. Thus reactions primed with DNA containing small amounts of contaminating poly[d(A-T)] will eventually result in complete domination of the synthesis by poly[d(A-T)]. This problem can be overcome by the addition to the reaction mixture of the synthetic quinoxaline antibiotic TANDEM which binds specifically to poly[d(A-T)] completely inhibiting its replication. Using thermal denaturation experiments it can be shown that TANDEM does not bind to most other synthetic DNA polymers (e.g., poly(dA) . poly(dT) and poly[d(A-T-C)] . poly[d(G-A-T)] and therefore their replication is not inhibited. The only exception we have encountered is poly[d(T-A-C)] . poly[d(G-T-A)] which does bind TANDEM and therefore the drug cannot be used during the synthesis of this polymer. The fact that poly[d(T-A-C)] . poly[d(G-T-A)] does bind TANDEM while poly[d(A-T-C)] . poly[d(G-A-T)] does not, suggests that the drug recognizes T-A rather than A-T sequences.

Inhibition of Escherichia coli Trimethylamine-N-oxide Reductase by Food Preservatives 1

Trimethylamine-N-oxide (TMA-O) reductase activity of resting cells of Escherichia coli was inhibited by tetrasodium ethylenediaminetetraacetate (Na₄EDTA), benzoic acid (BA and methylparaben (MP). The 50% inhibitory concentrations of Na₄EDTA, BA and MP were 20.2, 1.2 and 32.4 mM, respectively. BA at pH 6.5 or below most effectively inhibited the TMA-O reductase. Sorbic acid (SA), up to 0.70 mM, had no effect on TMA-O reductase activity, but SA inhibited the growth and subsequent TMA production in E. coli at or above 0.3S mM.

A rapid, simple and reliable test for the routine identification of urease producing gram-negative bacteria

The present investigation was prompted by the need to find a simple, rapid, reliable and low-cost method for the routine identification of urease producing bacteria. This method uses Nessler's reagent as an indicator of the presence of volatile ammonia produced by organisms which possess urease. The proposed method is comparable to the conventional Christensen's agar method, but is simpler and more rapid to perform.

cDNA clones coding for the heavy chain of human HLA-DR antigen

Two cDNA clones, pDRH1 and pDRH2, containing sequences specific for human HLA-DR antigens were isolated from a bank of cDNA clones made from partially purified HLA-DR mRNA from the human lymphoblastoid cell line Maja. The clones were specific for the Mr 34,000 HLA-DR antigen glycoprotein chain. The identity of these clones was established by (i) their ability to hybridize specifically to HLA-DR mRNA in a positive selection assay; (ii) mRNA species hybridizing to the cDNA clones were expressed in B-cell but not in T-cell or fibroblast cell cultures; and (iii) a nucleotide sequence in the longer clone, pDRH2, could be translated into an amino acid sequence that is identical to the limited NH2-terminal amino acid sequence available for the purified HLA-DR antigen Mr 34,000 chain. Analysis of DNA from human, mouse, and human--mouse somatic cell hybrid lines by Southern transfer of restriction endonuclease digests indicated that the HLA-DR heavy chain is encoded in chromosome 6. This finding is compatible with the location of at least one of the HLA-D/DR heavy chain genes within the HLA region. In addition, the sequences coding for HLA-DR heavy chain appear to be present in only one or a few copies in the genome and to be relatively simple in structure.

Cloning and the nucleotide sequence of the genes for Escherichia coli ribosomal proteins L28 (rpmB) and L33 (rpmG)

The specialized transducing bacteriophage lambda dpyrE DNA was used as a source of DNA to clone two ribosomal protein genes rpmB (L28) and rpmG (L33) on the cloning vehicle pACYC184. Using one of these plasmids, the nucleotide sequence of these two genes and their flanking regions were determined. The amino acid sequences of both proteins deduced from the nucleotide sequences match with the amino acid sequences previously determined, with one exception. The nucleotide sequences suggest that these two ribosomal protein genes are cotranstribed. There was no expression of the second gene of the operon, rpmG, in the absence of the 5' sequences adjacent to the first gene, rpmB. Observation of the structure of mRNA also strongly supports the idea that rpmB and rpmG are in a single transcription unit whose order is: rpmBp-rpmB-rpmG-rpmGt.

Steady pressure-flow relationship of a model of the canine bronchial tree

Static pressure differences (deltaP) across the entire length and portions of a latex reproduction of a canine bronchial tree were measured during steady inspiratory or expiratory flow (V). The reproduction consists of a 10-cm length of trachea through bronchi of about 2 mm in diameter. The airflow was simulated by a water flow with tracheal Renolds number (Re0) in the range from 1,500 to 10,000. Loss in total pressure (deltaPt) was computed by summing deltaPt and V were well described (r greater than 0.98) by a dimensionless Rohrer equation deltaPt/deltaPd0 = A + B Re0 applicable to gas flow, in which deltaPd0 is a Poiseuille pressure drop. For expiratory deltaPt, A was about twice that for inspiration, while the values for B were nearly equal. Differences in kinetic energy between sites of static pressure measurement are important in determining loss in total pressure. Rohrer's equation is a good approximation to the phenomenological laws of steady inspiratory and expiratory flow-pressure relations in the canine bronchial tree for the range of Reynolds number investigated.

Radial keratotomy in fresh human cadaver eyes

Radial keratotomy in fresh human cadaver eyes produced corneal flattening varying from 6 to 11 diopters (D). There was no significant difference in the effectiveness of the incisions to the incisions to the limbus compared to incisions through the limbus. Eighty to ninety percent of the flattening effect was obtained after the first eight incisions. The preoperative keratotomy reading was not helpful in predicting the final result. Histopathology of the incised corneas revealed considerable variation in incision depth and demonstrates the difficulty in achieving deep incisions safely.

Modification of corneal curvature following radial keratotomy in primates

Radial keratotomy was performed on six stumptail monkey eyes (Macaca speciosa) and 22 owl monkey eyes (Aotus trivirgotus). Changes in keratometry, specular microscopy, and tonometry have been studied postoperatively for three to six months. Sixteen radial incisions in stumptail monkey eyes resulted in a significant mean corneal flattening of 2.75 diopters (P less than 0.005). This effect was stable with a mean 2.50 diopters flattening remaining six months after surgery. Sixteen radial incisions in ten owl monkey eyes resulted in a much greater short-term effect, with a mean 10.50 diopters of flattening present at two weeks postoperatively. This flattening deteriorated over the observation period, and no significant effect was noted three months after surgery. A comparison of 8 vs 16 incisions on owl monkey eyes demonstrated that these two procedures are equally effective in initially flattening the cornea. Complications and side effects encountered included perforations, irregular astigmatism, corneal neovascularization, transitory increase in pachometry, and decrease in central corneal endothelial cell density in isolated cases.