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Proteus mirabilis and Klebsiella aerogenes are Gram-negative opportunistic pathogens that are responsible for nosocomial and health care-associated infections, including urinary tract infections. Here, the full genome sequences of six Chi-like Proteus (DanisaurMW, DoubleBarrel, Inception, Jing313, and NotEvenPhaged) or Klebsiella (Phraden) bacteriophages are announced, contributing to the understanding of Chi-like phages.

The Enterobacteriales order is composed of Gram-negative bacteria that range from harmless symbionts to well-studied pathogens. We announce complete genome sequences of five related SO-1-like Enterobacteriales bacteriophages (also known as the Dhillonvirus genus) isolated from wastewater that infect Escherichia coli (Opt-212, Over9000, Pubbukkers, and Teewinot) or Shigella boydii (StarDew).

The

Pacific island countries have not been part of the horticultural “revolution” that has driven broadly based growth in other comparable regions (e.g., East Africa). The disappointing performance of Pacific island horticultural exports can be explained by a combination of factors, which include the inability to resolve phyto-sanitary and other market access issues. Two case studies of exports to Australia are examined: Fiji fresh taro and ginger. Both products have market access but it is not economical to ship because of the unreasonable severity of the quarantine protocols in place. The WTO/International Sanitary and phyto-sanitary (SPS) Agreement principles of consistency and equivalence in phyto-sanitary measures and their application, are seen as relevant in these cases. Yet the “tyranny” of unequal size and available resources means there is little likelihood of a small country from the Pacific island countries mounting a successful challenge. The reform of such trade barriers needs to be negotiated in a broader political and economic context. The paper makes recommendations for mechanisms to “level the playing field” to facilitate Pacific island horticulture exports.

In this paper we shall re-visit the well-known Schrodinger equation of quantum mechanics. However, this shall be realized as a marginal dynamics of a more general, underlying stochastic counting process in a complex Minkowski space. One of the interesting things about this formalism is that its derivation has very deep roots in a new understanding of the differential calculus of time. This Minkowski-Hilbert representation of quantum dynamics is called the Belavkin formalism; a beautiful, but not well understood theory of mathematical physics that understands that both deterministic and stochastic dynamics may be formally represented by a counting process in a second-quantized Minkowski space. The Minkowski space arises as a canonical quantization of the clock, and this is derived naturally from the matrix-algebra representation [1, 2] of the Newton-Leibniz differential time increment, dt. And so the unitary dynamics of a quantum object, described by the Schrodinger equation, may be obtained as the expectation of a counting process of object-clock interactions.

We obtained intervertebral discs with cartilage endplates and underlying cancellous bone at operation from patients with degenerative disc disease and then used immunohistochemical techniques to localise the nerves and nerve endings in the specimens. We used antibodies for the ubiquitous neuronal protein gene product 9.5 (PGP 9.5). Immunoreactivity to neuropeptide Y was used to identify autonomic nerves and calcitonin gene-related peptide (CGRP) and substance P to identify sensory nerves. Blood vessels were identified by immunoreactivity with platelet-endothelial cell-adhesion molecule (CD31; PECAM). In a control group with no known history of chronic back pain, nerve fibres immunoreactive to PGP 9.5 and neuropeptide Y were most closely related to blood vessels, with occasional substance P and CGRP immunoreactivity. In patients with severe back pain and markedly reduced disc height, proliferation of blood vessels and accompanying nerve fibres was observed in the endplate region and underlying vertebral bodies. Many of these nerves were immunoreactive to substance P or CGRP, and in addition, substance P- and CGRP-immunoreactive nociceptors were seen unrelated to blood vessels. Quantification by image analysis showed a marked increase in CGRP-containing sensory nerve fibres compared with normal control subjects. We speculate that a chemotactic response to products of disc breakdown is responsible for the proliferation of vascularity and CGRP-containing sensory nerves found in the endplate region and vertebral body adjacent to degenerate discs. The neuropeptides substance P and CGRP have potent vasodilatory as well as pain-transmitting effects. The increase in sensory nerve endings suggests increase in blood flow, perhaps as an attempt to augment the nutrition of the degenerate disc. The increase in the density of sensory nerves, and the presence of endplate cartilage defects, strongly suggest that the endplates and vertebral bodies are sources of pain; this may explain the severe pain on movement experienced by some patients with degenerative disc disease.

We have studied the ability of a range of antibiotics to penetrate intervertebral disc tissue in vitro, using a mouse disc model. Equilibrium concentrations of antibiotics incorporated into the entire disc were determined by bioassay using a microbial growth-inhibition method. Uptake was significantly higher with positively-charged aminoglycosides compared with negatively-charged penicillins and cephalosporins. Uncharged ciprofloxacin showed an intermediate degree of uptake. Our results support the hypothesis that electrostatic interaction between charged antibiotics and negatively-charged glycosaminoglycans in the disc is an important factor in antibiotic penetration, and may explain their differential uptake.

The pathogeneses of parathyroid disease in patients with uremia and nonfamilial primary parathyroid hyperplasia are poorly understood. Because of multigland involvement, it has been assumed that these common diseases predominantly involve polyclonal (non-neoplastic) cellular proliferations, but an overall assessment of their clonality has not been done. We examined the clonality of these hyperplastic parathyroid tumors using X-chromosome inactivation analysis with the M27 beta (DXS255) DNA polymorphism and by searching for monoclonal allelic losses at M27 beta and at loci on chromosome band 11q13. Fully 7 of 11 informative hemodialysis patients (64%) with uremic refractory hyperparathyroidism harbored at least one monoclonal parathyroid tumor (with a minimum of 12 of their 19 available glands being monoclonal). Tumor monoclonality was demonstrable in 6 of 16 informative patients (38%) with primary parathyroid hyperplasia. Histopathologic categories of nodular versus generalized hyperplasia were not useful predictors of clonal status. These observations indicate that monoclonal parathyroid neoplasms are common in patients with uremic refractory hyperparathyroidism and also develop in a substantial group of patients with sporadic primary parathyroid hyperplasia, thereby changing our concept of the pathogenesis of these diseases. Neoplastic transformation of preexisting polyclonal hyperplasia, apparently due in large part to genes not yet implicated in parathyroid tumorigenesis and possibly including a novel X-chromosome tumor suppressor gene, is likely to play a central role in these disorders.

This paper is about three classes of objects: Leonard pairs, Leonard triples, and the finite-dimensional irreducible modules for an algebra $\mathcal{A}$. Let $\K$ denote an algebraically closed field of characteristic zero. Let $V$ denote a vector space over $\K$ with finite positive dimension. A Leonard pair on $V$ is an ordered pair of linear transformations in End$(V)$ such that for each of these transformations there exists a basis for $V$ with respect to which the matrix representing that transformation is diagonal and the matrix representing the other transformation is irreducible tridiagonal. Whenever the tridiagonal matrices are bipartite, the Leonard pair is said to be totally bipartite. A mild weakening yields a type of Leonard pair said to be totally almost bipartite. A Leonard pair is said to be totally B/AB whenever it is totally bipartite or totally almost bipartite. The notion of a Leonard triple and the corresponding notion of totally B/AB are similarly defined. There are families of Leonard pairs and Leonard triples said to have Bannai/Ito type. The Leonard pairs and Leonard triples of interest to us are totally B/AB and of Bannai/Ito type. Let $\mathcal{A}$ denote the unital associative $\K$-algebra defined by generators $x,y,z$ and relations\[xy+yx=2z,\qquad yz+zy=2x,\qquad zx+xz=2y.\]The algebra $\mathcal{A}$ has a presentation involving generators $x,y$ and relations\[x^{2}y+2xyx+yx^{2}=4y,\qquad y^{2}x+2yxy+xy^{2}=4x.\] In this paper we obtain the following results. We classify up to isomorphism the totally B/AB Leonard pairs of Bannai/Ito type. We classify up to isomorphism the totally B/AB Leonard triples of Bannai/Ito type. We classify up to isomorphism the finite-dimensional irreducible $\mathcal{A}$-modules. We show that these three classes of objects are essentially in one-to-one correspondence, and describe these correspondences in detail.

Human FcR for IgG can be divided into three classes (Fc gamma RI, II, and III) based on their structure and reactivity with mAb. Fc gamma RII can be further subdivided into two categories based on functional and biochemical assays. These two Fc gamma RII subtypes were initially recognized by the failure of T cells from 40% of individuals to proliferate in response to mAb Leu 4 (mouse IgG1, anti-CD3), a response that requires the binding of the Fc region of the Leu 4 mAb to Fc gamma RII on monocyte accessory cells. Inas-much as mouse IgG1, does not bind efficiently to the nonresponder form of Fc gamma RII, mAb Leu 4 is unable to induce proliferation in these individuals. IEF data on Fc gamma RII from Leu 4 responder and nonresponder individuals suggested that the structural gene for Fc gamma RII consisted of two allelic forms R (responder) and N (nonresponder) producing the phenotypes RR, RN, and NN. Thus, exclusive expression of the nonresponder allele in monocytes of "nonresponder" individuals, appeared to be responsible for the lack of proliferation observed. In cooperation with the IVth International Conference on Human Leukocyte Differentiation Antigens, we analyzed CDw32 mAb to determine if they could distinguish the responder and nonresponder forms of Fc gamma RII. We report that mAb 41H16 binds preferentially to the responder allotypic form of Fc gamma RII expressed on human monocytes. When quantitative flow cytometry is used to measure the binding of both mAb 41H16 (responder Fc gamma RII) and mAb IV.3 (all myeloid cell Fc gamma RII), we are able to subdivide the responder population into homozygous and heterozygous responders. In addition, mAb 41H16 blocks the binding of mAb IV.3 to monocytes and inhibits proliferation when added to cells before addition of mAb Leu 4. We also show that polymorphonuclear leukocytes and platelets have the same allotypic differences in the binding of 41H16 as do monocytes. However, a subset of lymphocytes (previously shown to be B cells) expresses the 41H16 epitope with no evidence for donor to donor variability.

Study design: A case report of Neisseria sicca/subflava discitis in a healthy elderly female. Objective: To report a rare case, which is usually seen exclusively in children. Setting: Stoke on Trent, England. Method: Case report, a 65-year-old female with a 6 month history of back and bilateral leg pain. X-rays showed collapse of L4/5 disc. No neurological deficit. Magnetic resonance imaging supported the clinical suspicion of discitis. Percutaneous biopsy followed 2 weeks later by open biopsy with bilateral root decompression was performed. Culture of L4/5 disc tissue produced Neisseria sicca/subflava. The patient was treated with a 4-week course of intravenous amoxycillin. Follow-up at 3 months confirmed clinical resolution of original symptoms. Conclusion: Any organism cultured from biopsy needs to be interpreted within the context of the clinical case. If clinical suspicion is high, further weight must be added to the finding of unusual or environmental organisms and culture of a repeat aspirate or biopsy may clarify the significance.

Ischemia/reperfusion (I/R), a phenomenon that is associated with conditions such as organ transplantation, trauma, vascular disease, and stroke, involves the recruitment of activated and adherent leukocytes that subsequently mediate tissue injury. Endothelial cell adhesion molecules such as P-selectin mediate I/R-induced leukocyte recruitment and allow the adherent leukocytes to damage the vascular wall and parenchymal cells. This study examines the influence of dypiridamole (persantine) on hemorrhagic shock (H/S)-induced P-selectin expression. H/S was induced in C57BL/6 mice by withdrawing blood to drop the mean arterial blood pressure to 30 to 35 mm Hg for 45 minutes. The mice were resuscitated by infusing the shed blood and Ringer's lactate (50% shed blood volume). In vivo P-selectin expression was determined using a dual monoclonal antibody technique in the heart, lung, liver, kidneys, stomach, small bowel, and colon of a control group, a hemorrhagic shock group, and a hemorrhagic shock group that was pretreated with Persantine (Boehringer, Ingelheim, Ingelheim, Germany). H/S significantly (P0.01) increased P-selectin expression in all regional vascular beds of untreated mice. Persantine treatment largely prevented the H/S-induced P-selectin expression in the same vascular beds. Persantine significantly attenuates the upregulation of P-selectin in the hemorrhagic shock model.

Ischemic preconditioning has been shown to protect some tissues from ischemia/reperfusion (I/R) injury. Adenosine is believed to play an important role by attenuating leukocyte-endothelial cell adhesive interactions. Dipyridamole increases adenosine bioavailability. The purpose of this study was to evaluate the effects of mechanical (MPC) and pharmacological preconditioning (PPC) on leukocyte endothelial cell interaction in hepatic I/R injury.C57BL6 mice were subjected to 30 min of ischemia to the left lobe of the liver. Groups tested at 30 min, 2, 5, 12, and 24 hr of reperfusion had 1) sham laparotomy (n = 10, 2) I/R (n = 25), 3) ischemic preconditioning with 5 min of ischemia and 10 min reperfusion before I/R (n = 25), and 4) (PPC) with dipyridamole (n = 25). Intravital microscopic examination was used to assess leukocyte/endothelial cell adhesion. Blood was drawn for leukocyte counts and liver function tests.A significant decrease in leukocyte rolling was observed at 30-min and 5-hr reperfusion intervals in the PPC and ischemic preconditioning groups compared with the I/R group. A significant decrease in leukocyte saltation was also observed in the PPC and MPC groups at 2, 5, and 12 hr of reperfusion when compared with the I/R group. aspartate aminotransferase was significantly decreased in the 5-hr preconditioning groups. There was not a significant decrease in the white blood cell count because of PPC or MPC vs. I/R CONCLUSIONS: Preconditioning decreases endothelial/ leukocyte interaction and reduces liver damage as measured by aspartate aminotransferase. These data prove that IPC and PPC provide some degree of hepatic protection in I/R injury.

Mechanisms of injury in hepatic ischemia/reperfusion injury are poorly defined. Leukocytes are thought to be important in the final mechanism of hepatic damage. We intend to show the time course of abnormal leukocyte activity in the liver after ischemia/reperfusion (I/R) injury. Left lobar hepatic ischemia was induced for 20 min in anesthetized C57B1-6 mice. Measurements were taken at control, reperfusion, and matching sham times (no ischemia) of 2, 5, 12, and 24 h. Measurements were taken using rhodamine and fluorescein enhanced intravital microscopy. Post sinusoidal venules were evaluated for numbers of rolling leukocytes, leukocyte saltation, and leukocyte velocity. Data are expressed as number of rolling leukocytes per 100 microns venule length (2 min). Statistical analysis was by ANOVA. The number of rolling leukocytes at 5, 12, and 24 h of reperfusion (p0.001) was significantly higher than control and sham-operated animals. Leukocyte velocities were significantly slower in the 12 h I/R group when compared to sham animals (p0.001). These data show that there are definable and quantifiable changes in leukocyte kinetics in the liver after ischemia/reperfusion. These changes, which lasted for 24 h, are likely due to upregulation of various endothelial cell adhesion molecules. Delineation of these mechanisms may be important in disease states such as shock, sepsis, and hepatic transplantation.

We obtained intervertebral discs with cartilage endplates and underlying cancellous bone at operation from patients with degenerative disc disease and then used immunohistochemical techniques to localise the nerves and nerve endings in the specimens. We used antibodies for the ubiquitous neuronal protein gene product 9.5 (PGP 9.5). Immunoreactivity to neuropeptide Y was used to identify autonomic nerves and calcitonin gene-related peptide (CGRP) and substance P to identify sensory nerves. Blood vessels were identified by immunoreactivity with platelet-endothelial cell-adhesion molecule (CD31; PECAM). In a control group with no known history of chronic back pain, nerve fibres immunoreactive to PGP 9.5 and neuropeptide Y were most closely related to blood vessels, with occasional substance P and CGRP immunoreactivity. In patients with severe back pain and markedly reduced disc height, proliferation of blood vessels and accompanying nerve fibres was observed in the endplate region and underlying vertebral bodies. Many of these nerves were immunoreactive to substance P or CGRP, and in addition, substance P- and CGRP-immunoreactive nociceptors were seen unrelated to blood vessels. Quantification by image analysis showed a marked increase in CGRP-containing sensory nerve fibres compared with normal control subjects. We speculate that a chemotactic response to products of disc breakdown is responsible for the proliferation of vascularity and CGRP-containing sensory nerves found in the endplate region and vertebral body adjacent to degenerate discs. The neuropeptides substance P and CGRP have potent vasodilatory as well as pain-transmitting effects. The increase in sensory nerve endings suggests increase in blood flow, perhaps as an attempt to augment the nutrition of the degenerate disc. The increase in the density of sensory nerves, and the presence of endplate cartilage defects, strongly suggest that the endplates and vertebral bodies are sources of pain; this may explain the severe pain on movement experienced by some patients with degenerative disc disease.

Rats gathered pellets from the tops of 15.5-cm-tall poles. In a matrix of poles, bait was located on the tops of poles arranged in either a square (Experiment 1) or linear (Experiment 2) configuration. The specific locations of baited poles varied unpredictably from trial to trial. The data show that the rats' choices were controlled by the spatial configuration of baited locations. This indicates that the rats represented the geometric pattern formed by the locations of food.

The causes of gastrointestinal hemorrhage in children were detailed in 1964 by Spencer. We investigated the causes of gastrointestinal hemorrhage in 165 children seen at our institution over a 13-year period. The most common causes of gastrointestinal hemorrhage in the hospitalized patients were necrotizing enterocolitis (44%), anal fissures (23%), and guaiac-positive stools of unknown cause (16%). The mortality rate was 5.4%. Necrotizing enterocolitis was the most common cause of death. Only 16 patients required surgery. Gastrointestinal hemorrhage is an infrequent cause of mortality and morbidity in hospitalized pediatric patients.

Retention of the host's Descemet's membrane is an unusual complication of penetrating keratoplasty. The membrane may opacify and even threaten the health of the transplant. Following creation of a central opening with the Nd:YAG laser in such a case, visual acuity improved from counts fingers at 5 ft to 20/100.

In 6 experiments, the performance of male rats in a 12-arm radial maze was examined. The focus of study was the extent to which the spatial location of individual baited maze arms was determined before the rat was exposed to the extramaze visual cues corresponding to the arm, and thereby guided the rat toward the location of baited arms. Such spatial guidance of choice behavior implies a spatially organized cognitive representation of maze arms (i.e., a cognitive map). A higher level of spatial guidance was found when visual access to extramaze cues was restricted than when it was unrestricted. There was no evidence of a difference between the level of spatial guidance in the context of working memory performance and reference memory performance. Some evidence that intramaze cues contributed to microchoice guidance was found. However, spatial guidance, under at least some conditions, is best explained in terms of cognitive mapping.

Cystic lesions of the mesentery, omentum, and retroperitoneum are rare; from 1956 to 1990, 22 patients had operative treatment for such lesions at our institution. They ranged in age from 1 month to 14 years; 75% were younger than 5 years. All had either an acute abdomen or, more commonly, a silent abdominal mass. In all cases, the histologic diagnosis was lymphangioma. Abdominal ultrasonography was done in all cases after 1977 except for two patients who had an acute abdomen requiring emergency exploration. A cystic abdominal mass was diagnosed in 94% of these cases, but the correct diagnosis of lymphangioma was made prior to surgery in only 24%. Mesenteric cysts are most common in the small bowel mesentery. Omental cysts usually occur singly and are easily resected, but multiple cysts predominate in the mesentery and retroperitoneum. Complete resection was accomplished in 82% of our cases. Two patients required partial bowel resection, and four had partial excision with marsupialization of the cysts. With a mean follow-up of 23 months, we have had three recurrences, but none necessitated reexploration. Extra-abdominal lesions, mainly cutaneous lymphangiomas, developed in two cases. Prognosis is good after surgical excision, but long-term follow-up is advisable because of the possibility of recurrence, even during adulthood.

Mesenteric hypoperfusion may be responsible for alterations in gut mucosa leading to necrotizing enterocolitis. Platelet-activating factor (PAF) and cocaine have been implicated in the etiology of necrotizing enterocolitis. We have demonstrated direct toxic effects of these compounds in vitro, but the in vivo mechanism of bowel damage is unknown. Newborn piglets (3.0 +/- 0.3 kg) had physiologic parameters (electrocardiogram, blood pressure, pulse, and central venous pressure) continuously monitored as well as Doppler probe recordings of superior mesenteric artery flow (Qsma). Aortic flow with calculation of cardiac index, and systemic and mesenteric vascular resistances (SVR and MVR) were also determined. Group 1 (N = 8) received PAF (0.5 microgram/kg). Groups 2 (N = 8) and 3 (N = 8) received high (17 mg/kg) and low (9 mg/kg) doses of cocaine, respectively. Each subject served as its own control. Histology demonstrated edema or early mucosal hemorrhage in all groups. PAF caused a third-degree atrioventricular block of short duration and a prolonged decrease of the cardiac index, but only a brief elevation of SVR and MVR. The cocaine groups had a sustained increase of SVR and MVR associated with a decrease of cardiac index. The decrease of Qsma paralleled the changes of MVR in each subject. These data show that both PAF and cocaine induce mesenteric ischemia. The effect of PAF is of short duration and mainly related to its cardiotoxic effects resulting in low Qsma. Cocaine causes an increase in MVR with prolonged depression of mesenteric flow.(ABSTRACT TRUNCATED AT 250 WORDS)

A fracture is the bony manifestation of an injury to part of the body, usually a limb, and is necessarily associated with a soft tissue injury. The severity of the overall injury may bear little relation to, for example, the radiographic appearance of the fracture itself. The degree of disruption of the soft tissues affects the degree of interference with the blood supply of the injured area, and this is influenced by such factors as the velocity of injury.

It was recently shown that oligolamellar vesicles of 3:1 mixtures of dioleoylphosphatidylethanolamine (DOPE) and the photopolymerizable lipid 1,2-bis[10-(2',4'-hexadienoyloxy)decanoyl]-sn-glycero-3-phosphocho line (SorbPC) are destabilized by polymerization of the SorbPC [Lamparski, H., Liman, U., Frankel, D.A., Barry, J.A., Ramaswami, V., Brown, M.F.,O'Brien, D.F. (1992) Biochemistry 31, 685-694]. The current work describes the polymorphic phase behavior of these mixtures in extended bilayers, as studied by 31P NMR spectroscopy and X-ray diffraction. In the NMR experiments, samples with varying degrees of polymerization were slowly raised in temperature, with spectra acquired every 2.5-10 degrees C. In the unpolymerized mixiture, and in those photopolymerized samples where the monomeric SorbPC was decreased by 33% and 51%, an isotropic signal grew progressively until no signal from the lamellar liquid-crystalline (L alpha) phase remained. In the highly polymerized sample with a 90% loss of monomeric SorbPC, less than 20% of the lipids underwent this transition. In none of the samples was an inverted hexagonal phase (HII) observed, under conditions of slow heating to almost 100 degrees C. The X-ray diffraction studies indicated that samples which exhibit the isotropic NMR signal corresponded to a structure exhibiting no well-defined crystalline order, which upon thermal cycling became an inverted cubic phase belonging to either the Pn3m or Pn3 space groups. The temperature of the transition to the cubic precursor decreased as the extent of polymerization increased, demonstrating that photopolymerization of these lipid bilayers can significantly alter the composition and thermotropic phase behavior of the mixture.

Fifteen rats performed in a standard radial-arm maze task (Experiment 1) and in a modified task with a set of forced choices and a 15-min retention interval prior to completion of the maze (Experiment 2). In addition to the standard measure of choice in the radial-arm maze, orientation toward arms was measured and considered to constitute go-no-go "microchoice" decisions. Rats investigated but rejected many arms. A model of choice was developed in which it was assumed that choice decisions about arms were made independently and that microchoices were not selectively guided toward baited arms. The model performed nearly as well as the rats. These results place important limitations on the theory that choice behavior in the radial-arm maze is guided by a cognitive map.

Polyunsaturated fatty acids are widely distributed components of biological membranes and are believed to be involved in many biological functions. However, the mechanisms by which they act on a molecular level are not understood. To further investigate the unique properties of omega 3 polyunsaturated phospholipid bilayers, deuterium nuclear magnetic resonance (2H NMR) studies have been made of the liquid-crystalline (L alpha) and gel phases of a homologous series of mixed-chain phosphatidylcholines containing docosahexaenoic acid: (per-2H-n:0)(22:6)PC, where n = 12, 14, 16, and 18. The moments of the 2H NMR lineshapes have been evaluated, and from these the warming and cooling main phase transition temperatures were determined. The transition temperatures of the mixed-chain series were found to be significantly lower than those of the corresponding lipids in the disaturated series, di(per-2H-n:0)PC, with hystereses ranging from 2 to 14 degrees C. Distinct effects of the docosahexaenoyl chain on bilayer order were found, though these effects varied across the mixed-chain series. In evaluating the moment data, an empirical method for normalizing the moments with respect to differences in temperature was applied, in addition to using the reduced temperature method. For the systems studied here, the method of normalization had no significant effect on the interpretation of the moment data.

The configurational properties and dynamics of the arachidonic acyl chains of phospholipid bilayers have been investigated for the first time by solid-state 2H NMR techniques, with the goal of achieving a better understanding of the biological roles of polyunsaturated phospholipids. Vinyl perdeuterated arachidonic acid (20:4 delta 5,8,11,14-d8) was prepared from eicosatetraynoic acid (ETYA) and was esterified with 1-palmitoyl-sn-glycero-3-phosphocholine to yield 1-palmitoyl-2-vinylperdeuterioarachidonoyl-sn-glycero-3-phosphocho line [(16:0)(20:4-d8)PC]. 31P NMR spectra of aqueous dispersions of (16:0)(20:4-d8)PC as well as 1-perdeuteriopalmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine [(per-2H-16:0)(20:4)PC] were characteristic of the lamellar liquid-crystalline state. The dispersions had similar 31P chemical shift anisotropies, with little apparent motional averaging of the lineshapes due to macroscopic reorientation of liposomes or lateral diffusion of phospholipids about their curved surfaces. Comparison to other phosphatidylcholines indicated that both samples comprised the fully hydrated L alpha phase plus excess water. However, the dispersion of (16:0)(20:4-d8)PC yielded relatively narrow powder-type 2H NMR spectra, compared to (per-2H-16:0)(20:4)PC in the liquid-crystalline state. The differences in the 2H NMR powder patterns thus reflect differences in the configurational properties of the polyunsaturated sn-2 arachidonic acyl chain compared to the saturated sn-1 palmitic chain. When the powder-type 2H NMR spectra of the (16:0)(20:4-d8)PC bilayer were dePaked (theta = 0 degrees), they showed three kinds of deuterons upon integration: one with a large splitting (approximately 25-35 kHz), two with intermediate splittings (approximately 10-15 kHz), and the remainder with smaller splittings (approximately 0.3-5 kHz).(ABSTRACT TRUNCATED AT 250 WORDS)

Various approaches to reliable, low maintenance, low resupply regenerative long-term life support for lunar base application are discussed. The first approach utilizes Space Station Freedom physiochemical systems technology which has closed air and water loops with approximately 99 and 90 percent closure respectively, with minor subsystem changes to the SSF baseline improving the level of water resupply for the water loop. A second approach would be a physiochemical system, including a solid waste processing system and improved air and water loop closure, which would require only food and nitrogen for resupply. A hybrid biological/physiochemical life support system constitutes the third alternative, incorporating some level of food production via plant growth into the life support system. The approaches are described in terms of mass, power, and resupply requirements; and the potential evolution of a small, initial outpost to a large, self-sustaining base is discussed.

Pigeons were trained to match color and line orientation element or compound samples in a symbolic matching-to-sample task. In subsequent test sessions with element and compound samples, there was an initial superiority of element matching for the element-trained group and of compound matching for the compound-trained group. This difference persisted over the course of 100 test sessions for the element-trained group, whereas element- and compound-matching accuracy converged for the compound-trained group. In a second experiment, in which sample duration was manipulated, element-matching accuracy was superior to compound-matching accuracy for both groups. Thus, element-matching accuracy was superior to compound-matching accuracy under conditions that rule out generalization decrement and training history as explanations. The data are interpreted as supporting the view that the dimensions of visual compound stimuli compete for a limited cognitive resource.

Human FcR for IgG can be divided into three classes (Fc gamma RI, II, and III) based on their structure and reactivity with mAb. Fc gamma RII can be further subdivided into two categories based on functional and biochemical assays. These two Fc gamma RII subtypes were initially recognized by the failure of T cells from 40% of individuals to proliferate in response to mAb Leu 4 (mouse IgG1, anti-CD3), a response that requires the binding of the Fc region of the Leu 4 mAb to Fc gamma RII on monocyte accessory cells. Inas-much as mouse IgG1, does not bind efficiently to the nonresponder form of Fc gamma RII, mAb Leu 4 is unable to induce proliferation in these individuals. IEF data on Fc gamma RII from Leu 4 responder and nonresponder individuals suggested that the structural gene for Fc gamma RII consisted of two allelic forms R (responder) and N (nonresponder) producing the phenotypes RR, RN, and NN. Thus, exclusive expression of the nonresponder allele in monocytes of "nonresponder" individuals, appeared to be responsible for the lack of proliferation observed. In cooperation with the IVth International Conference on Human Leukocyte Differentiation Antigens, we analyzed CDw32 mAb to determine if they could distinguish the responder and nonresponder forms of Fc gamma RII. We report that mAb 41H16 binds preferentially to the responder allotypic form of Fc gamma RII expressed on human monocytes. When quantitative flow cytometry is used to measure the binding of both mAb 41H16 (responder Fc gamma RII) and mAb IV.3 (all myeloid cell Fc gamma RII), we are able to subdivide the responder population into homozygous and heterozygous responders. In addition, mAb 41H16 blocks the binding of mAb IV.3 to monocytes and inhibits proliferation when added to cells before addition of mAb Leu 4. We also show that polymorphonuclear leukocytes and platelets have the same allotypic differences in the binding of 41H16 as do monocytes. However, a subset of lymphocytes (previously shown to be B cells) expresses the 41H16 epitope with no evidence for donor to donor variability.

Sir, I read with interest the article by Ng and Sell[1][1] in the May 2004 issue entitled “Predictive value of the duration of sciatica for lumbar discectomy”. It is a rigorous assessment of this much debated question, but to call it a prospective, cohort study, despite the fact that the

One hundred fifty-four patients with renovascular injuries were analyzed to gain insight into the mortality, morbidity and indications for immediate nephrectomy versus arterial revascularization. Arterial revascularization is seldom indicated in patients with a normal contralateral kidney who have multiple associated injuries, hilar injuries, long segmental arterial injuries or prolonged renal ischemia. An attempt at renal artery revascularization is justified with bilateral injuries, when only one kidney is present or when a solitary artery injury can be repaired by simple lateral arteriorrhaphy.

An experimental basis is provided for the theoretical expressions associated with the Eρ lateral‐wave field due to a horizontal dipole in a conducting half‐space of sea water. Both perturbed and unperturbed fields are studied in detail in a laboratory model of the lithosphere. It is found that rectilinear and wedge‐shaped discontinuities at the air‐water interface comprise effective perturbations of Eρ, while submerged metallic cylinders do not. The effective perturbations, localized in their effect on the overall propagation of the lateral wave over several wavelengths, have geometries chosen to characterize the broad plateaus and mountains of a real lithosphere.

Abundant conidiophores and conidia of Helminthosporium maydis were produced within 48 h on diseased corn leaf pieces. Observations of ultrastructure revealed that conidiogenesis in H. maydis is holoblastic; all layers of the conidiophore wall are involved in the initiation of conidia.

The interactions between soybean plants and two species of mycorrhizal fungi were examined. The number of infection units in young seedlings was found to increase in the presence of increasing quantities of Glomus fasciculatus inoculum, until a maximum was reached. Soybean seedlings remained free of mycorrhizal infection during early stages of development. First infection units appeared 10–12 days after planting which was also the approximate time that rhizobium root nodules and tertiary roots were first observed. The response to colonization by vesicular–arbuscular mycorrhizal fungi was evident as early as 6 weeks after planting.

A technique is described that employs vapor fixation and a simple vapor diffusion dehydration apparatus to minimize the disturbance of delicate fungal structures during preparation for scanning electron microscopy. The technique is applicable to fungi grown on agar media or on natural substrates.

A specific physical interpretation of the effect of relative permittivities er and conductivities σ upon the amplitude and phase of propagating electromagnetic surface waves is given, where ϵr and σ characterize the layered material regions of a planetary lithosphere. The interpretation is made possible by the availability of simple formulas for the fields of vertical and horizontal unit electric dipoles near interfaces between regions of matter; the earth's lithosphere at its interface with salt water is used as an example. The ranges of er, σ, frequency ƒ, and radial distance ρ over which the formulas apply are shown to be quite broad. The E1ρ component (the radial electric field in region 1, characterized by complex wave number K1 and adjoined at a planar interface to region 2, characterized by k2, where |k1|2 » |k1|2) is discussed in detail. The attenuation of 20 log10 |E1ρ| as a function of ρ and ρ/δ2, Where δ is the skin depth, is illustrated for conductivity ratios σ2/σ1 = 10−1 to 10−3, over a range of ƒ from 1 Hz to 105 Hz. |E1ρ| is shown to be significant for determining permittivities e2 at the higher frequencies in this range. The use of |E1ρ| to infer conductivities σ2 at lower frequencies in shallow sounding of the earth's sea floor is discussed in terms of specific lithological and sediment-related parameters. The technology required to transmit and receive 20 log10 |E1ρ| at freshwater and saltwater interfaces with the earth's crust is addressed. A specific experiment is proposed for testing a specialized insulated antenna for seafloor use in shallow coastal waters at 1 kHz.

A wave packet or pulse comprised of a distribution of single-frequency lateral waves due to a vertical monopole is analyzed. The Fresnel-integral terms in the Fourier transform of a general formula for E2z(ρ, z, ω), the vertical electric-field component in air, are represented using confluent hypergeometric functions. A wave packet of lateral waves is calculated for a pulsed short bare monopole at the boundary between a pair of Earth's material regions and compared with experimental measurements.

The vesicular–arbuscular mycorrhizal fungus Glomus mosseae was examined by transmission electron microscopy and energy dispersive X-ray analysis. Electron-dense granules, found within vacuoles, were analyzed by X-ray analysis and found to contain high concentrations of phosphorus and calcium. These granules were similar in appearance to the polyphosphate granules described in other organisms. Highly vacuolated intercellular hyphae and vesicles possessed the greatest number of phosphorus granules. The granules were present in vacuolated arbuscular hyphae but absent from completely collapsed arbuscules. It was determined that the active arbuscule was the most probable site of breakdown of phosphorus granules. There were two other types of cellular inclusions, one vacuolar and one cytoplasmic, that could not be identified by X-ray analysis but that could easily be mistaken for phosphorus granules. It was concluded that general morphological appearance and location were not adequate criteria for the identification of phosphorus granules.

Cellular requirements for induction of primary proliferative responses by human T cells to trinitrophenylated autologous stimulators have been characterized. Substantial proliferative responses were observed with each of the Ia+ stimulator populations tested. Nevertheless, major differences in the hapten specificity of such responses were observed. Thus purified macrophages/monocytes (M phi) when TNP-modified induced responses that were relatively modest in absolute magnitude, but were highly hapten specific. This reflected the very limited capacity of purified M phi to induce proliferation when unmodified, i.e., an autologous mixed leukocyte response (AMLR). In contrast, unmodified M phi-depleted B plus null cells were potent stimulators of AMLR, but hapten modification did not significantly enhance the responses induced by these cells. Moreover, when M phi were added to B plus null cell stimulators AMLR responses were reduced and, with TNP-modified stimulators, hapten-specific responses were restored. The data thus suggest that M phi may have important roles in induction of primary T cell responses to conventional antigens but function largely as regulators rather than stimulators of AMLR. Finally, we have introduced a novel antigen-presenting cell population, the irradiated Ia+ TNP-specific cloned T cell. The possibility that such cells may utilize autostimulatory positive feedback circuits for activation of naive T cells and in interactions between subpopulations of hapten-reactive T cells is discussed.