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Bartonella quintana, the agent of trench fever and a cause of endocarditis and bacillary angiomatosis in humans, has the highest reported in vitro hemin requirement for any bacterium. We determined that eight membrane-associated proteins from B. quintana bind hemin and that a approximately 25-kDa protein (HbpA) was the dominant hemin-binding protein. Like many outer membrane proteins, HbpA partitions to the detergent phase of a Triton X-114 extract of the cell and is heat modifiable, displaying an apparent molecular mass shift from approximately 25 to 30 kDa when solubilized at 100 degrees C. Immunoblots of purified outer and inner membranes and immunoelectron microscopy with whole cells show that HbpA is strictly located in the outer membrane and surface exposed, respectively. The N-terminal sequence of mature HbpA was determined and used to clone the HbpA-encoding gene (hbpA) from a lambda genomic library. The hbpA gene is 816 bp in length, encoding a predicted immature protein of approximately 29.3 kDa and a mature protein of 27.1 kDa. A Fur box homolog with 53% identity to the Escherichia coli Fur consensus is located upstream of hbpA and may be involved in regulating expression. BLAST searches indicate that the closest homologs to HbpA include the Bartonella henselae phage-associated membrane protein, Pap31 (58.4% identity), and the OMP31 porin from Brucella melitensis (31.7% identity). High-stringency Southern blots indicate that all five pathogenic Bartonella spp. possess hbpA homologs. Recombinant HbpA can bind hemin in vitro; however, it does not confer a hemin-binding phenotype upon E. coli. Intact B. quintana treated with purified anti-HbpA Fab fragments show a significant (P < 0.004) dose-dependent decrease in hemin binding relative to controls, suggesting that HbpA plays an active role in hemin acquisition and therefore pathogenesis. HbpA is the first potential virulence determinant characterized from B. quintana.

ABSTRACTBartonella quintana, the agent of trench fever and a cause of endocarditis and bacillary angiomatosis in humans, has the highest reported in vitro hemin requirement for any bacterium. We determined that eight membrane-associated proteins from B. quintanabind hemin and that a ∼25-kDa protein (HbpA) was the dominant hemin-binding protein. Like many outer membrane proteins, HbpA partitions to the detergent phase of a Triton X-114 extract of the cell and is heat modifiable, displaying an apparent molecular mass shift from approximately 25 to 30 kDa when solubilized at 100°C. Immunoblots of purified outer and inner membranes and immunoelectron microscopy with whole cells show that HbpA is strictly located in the outer membrane and surface exposed, respectively. The N-terminal sequence of mature HbpA was determined and used to clone the HbpA-encoding gene (hbpA) from a lambda genomic library. The hbpAgene is 816 bp in length, encoding a predicted immature protein of approximately 29.3 kDa and a mature protein of 27.1 kDa. A Fur box homolog with 53% identity to the Escherichia coliFur consensus is located upstream of hbpAand may be involved in regulating expression. BLAST searches indicate that the closest homologs to HbpA include the Bartonella henselaephage-associated membrane protein, Pap31 (58.4% identity), and the OMP31 porin from Brucella melitensis(31.7% identity). High-stringency Southern blots indicate that all five pathogenic Bartonellaspp. possess hbpAhomologs. Recombinant HbpA can bind hemin in vitro; however, it does not confer a hemin-binding phenotype upon E. coli. IntactB. quintanatreated with purified anti-HbpA Fab fragments show a significant (P< 0.004) dose-dependent decrease in hemin binding relative to controls, suggesting that HbpA plays an active role in hemin acquisition and therefore pathogenesis. HbpA is the first potential virulence determinant characterized fromB. quintana.

ABSTRACTp27Kip1is a member of the Cip-Kip family of cyclin-dependent kinase (Cdk) inhibitors that binds to cyclin-Cdk complexes and inhibits their catalytic activity in response to antiproliferative stimuli. p27Kip1is regulated by several posttranscriptional mechanisms, including subcellular localization. We have identified a component of the nuclear pore complex (NPC), termed Nup50, through its two-hybrid interactions with p27Kip1. Nup50 is a nucleoplasmically oriented component of the nuclear pore complex with a role in protein export (T. Guan, R. H. Kehlenbach, E. C. Schirmer, A. Kehlenbach, F. Fan, B. E. Clurman, N. Arnheim, and L. Gerace, Mol. Cell. Biol. 20:5619–5630, 2000). We found that murine Nup50 is a widely expressed nucleoporin and that Nup50 expression is highest in the developing neural tube and adult testes. We have also examined interactions between Nup50 and the NPC and found specific two-hybrid interactions between Nup50 and several well-defined components of the NPC, as well as coimmunoprecipitation of Nup50 with the nucleoporin Nup153 from transfected mammalian cells. In order to study Nup50 function in vivo, we cloned the mouse Nup50 genomic locus and created a targeted Nup50 deletion in the mouse germ line. Nup50 disruption resulted in a complex phenotype characterized by late embryonic lethality, neural tube defects, and intrauterine growth retardation. Although Nup50-null mouse embryo fibroblasts exhibited no defects in either cell cycle control or p27Kip1regulation, Nup50 deletion was associated with abnormalities in p27Kip1expression and cell proliferation in the developing neuroepithelium. We conclude that Nup50 is a nucleoporin with essential functions during mouse development.

Focusing on beryllium capsules, Los Alamos works toward ignition on the NIF, a first step to fusion power. Theory and experiments are giving us a greater understanding of laser plasma instabilities (SBS and SRS). A 1D Kirkpatrick-Baez microscope with < 1 μm resolution has been designed to observe shock timing. Tetrahedral hohlraum implosion experiments are being executed on Omega with symmetry better than cylindrical hohlraums on NIF. Understanding capsule instability growth, and experimentally testing it, is leading to new designs. The first NIF size beryllium capsule has been built from copper brazed hemispheres. Measurements of DT ice on beryllium show adequate smoothness and temperature cycling can reduce it further.

ABSTRACTThis study describes the first isolation and characterization of spontaneous mutants conferring natural resistance to an antibiotic for any Bartonellaspecies. The Bartonella bacilliformis gyrBgene, which encodes the B subunit of DNA gyrase, was cloned and sequenced. The gyrBopen reading frame (ORF) is 2,079 bp and encodes a deduced amino acid sequence of 692 residues, corresponding to a predicted protein of ∼77.5 kDa. Sequence alignment indicates that B. bacilliformisGyrB is most similar to the GyrB protein from Bacillus subtilis(40.1% amino acid sequence identity) and that it contains the longest N-terminal tail (52 residues) of any GyrB characterized to date. The cloned B. bacilliformis gyrBwas expressed in an Escherichia coliS30 cell extract and was able to functionally complement a temperature-sensitive E. coliCourgyrBmutant (strain N4177). We isolated and characterized spontaneous mutants of B. bacilliformisresistant to coumermycin A1, an antibiotic that targets GyrB. Sequence analysis of gyrBfrom 12 Courmutants ofB. bacilliformisidentified single nucleotide transitions at three separate loci in the ORF. The predicted amino acid substitutions resulting from these transitions are Gly to Ser at position 124 (Gly124→Ser), Arg184→Gln, and Thr214→Ala or Thr214→Ile, which are analogous to mutated residues found in previously characterized resistant gyrBgenes fromBorrelia burgdorferi, E. coli,Staphylococcus aureus, and Haloferaxsp. The Courmutants are three to five times more resistant to coumermycin A1than the wild-type parental strain.

We examined the roles of glutathione S-transferase (GST) P1-1 and the glutathione S-conjugate (GS-X) transporter, multidrug resistance protein 1 (MRP1), singly or in combination, in the detoxification of 1-chloro-2,4-dinitrobenzene (CDNB). Derivatives of MCF7 breast carcinoma cells expressing GST P1-1 and MRP1 alone or in combination were developed. Detoxification was measured in cells as formation of the glutathione conjugate of CDNB, S-(2,4-dinitrophenyl)-glutathione (DNP-SG), efflux of DNP-SG, and ultimately protection from CDNB cytotoxicity. MRP1 expression in the absence of GST P1-1 confers a three- to fourfold resistance to CDNB, which is associated with a >10-fold increase in the maximum rate of DNP-SG efflux. DNP-SG efflux in MRP1-expressing MCF7 cells was ATP-dependent and exhibited an apparent Kmfor DNP-SG of 95 μM. MRP1 expression alone, however, had no effect on DNP-SG formation. Combined expression of GST P1-1 and MRP1 increased the rates of DNP-SG formation when cells were exposed to 10 μM CDNB. Moreover, combined expression of GSTP1-1 with MRP1 moderately augmented MRP1-mediated resistance to CDNB but only during short term (10 min) exposures to CDNB where IC50values were in the 8–10 μM range. In contrast, expression of GST P1-1 in the absence of MRP1 slightly sensitized cells to the toxicity of CDNB (10 min exposures), despite increasing rates of DNP-SG formation. The sensitization to CDNB in cells expressing GST P1-1 alone was associated with increased intracellular accumulation of DNP-SG, indicating that DNP-SG may contribute to CDNB toxicity. The potential toxicity of DNP-SG is also suggested by the finding that inhibition of DNP-SG formation by prior glutathione depletion confers resistance to CDNB cytotoxicity in MRP1-poor MCF7 cells. Altogether, our results demonstrate that glutathione conjugation and MRP1-mediated conjugate efflux can operate together to confer resistance to CDNB. The data indicate that MRP1-mediated conjugate efflux is required for cytoprotection from CDNB because its conjugate (DNP-SG), when present at high intracellular levels, may also be toxic to cells.

The case of a 54-year-old housewife, oldest published survivor with pulmonary atresia and a ventricular septal defect (pseudotruncus arteriosus), is reported. Her remarkably favorable course is likely related to the absence of progressive hemodynamic changes, with moderate pulmonary flow adequate for nearly normal arterial oxygenation yet without increasing pulmonary vascular resistance. This case reemphasizes the relationship of longevity to pulmonary blood flow volume with this defect.

The purpose of this investigation was to determine whether long-term oral administration of commonly prescribed doses of quinidine sulfate and procainamide hydrochloride to patients with ischemic heart disease assessed by the systolic shortening fraction, the relative change in interclip distance from diastole to systole, was measured by cineradiography of metal clips that had been sutured to the epicardium at the time of coronary artery bypass surgery. Global contractility was assessed by gated blood-pool scintigraphy. Systolic shortening fraction determinations and scintigraphy were obtained following five to seven days’ administration of procainamide (500 mg every four hours), quinidine (200 mg every six hours), or neither drug in a random sequence. Serum drug levels milligrams per liter) were 1.8±0.8 (mean±1 SD) for quinidine and 3.7±1.1 for procainamide, when measured one hour before the next dose. During quinidine administration, mean segment shortening fraction decreased only slightly, but significantly (P<0.02), from 12.4 percent to 10.6 percent. The clinical importance of so small a change is questionable. During procainamide administration, there was a very small, insignificant (P>0.9), decrease in segmental shortening. Global left ventricular function was not significantly changed by either drug. It appears that both drugs can be used over long periods in commonly prescribed doses in patients with ischemic heart disease without a major overall deleterious effect on cardiac performance.

Traditional coding schemes for occupational health related factors eg, SIC, SOC, CAS are structured similarly as hierarchical, exclusive, and exhaustive systems. Each is limited to information of one particular type eg, industry and, therefore, the relationships implicit in the coding scheme are limited. This study empirically determined that “natural” coding schemes used by occupational health professionals do not share these characteristics but are more akin to semantic network data bases. There is therefore a need to reevaluate how occupational data are to be coded.

One hundred and eighty-seven each of channel catfish, Ictalurus punctatus, blue catfish, Ictalurus furcatus, and their reciprocal hybrid crosses were stocked communally in a 0.1-hectare pond (7,480 fish/hectare) in April 1977. Each group was heat-branded prior to stocking for subsequent identification. The fish were grown for 181 days, after which the pond was fished for 35 man-hours (350 man-hours/hectare) on October 16 and 17. The pond was drained on October 19 and the remaining fish were harvested. A total of 290 kg (518 fish) was harvested by fishing and draining. Seventy-five (14.5%) of the fish were caught by the anglers in the two days. The hybrids were more susceptible to angling than the parent species. Heterosis for catchability was 158.6% by number and 203.6% by weight of fish caught. Channel catfish ? x blue catfish ? hybrids were more catchable than the reciprocal hybrids. Average length of all fish that were caught was greater than for those that were not caught. Fishing success in fee-fishing catfish ponds could be improved by stocking the channel catfish ? x blue catfish ? hybrid.

Twelve patients with healed congenital pseudarthrosis of the tibia underwent gait analysis and muscle strength testing to determine the functional result of treatment. Six children younger than 4 years of age presented with pseudarthroses (early onset), and six children first fractured at older than 4 years of age (delayed onset). Four children with amputations as final treatment for congenital pseudarthrosis were studied for comparison. The early-onset group had undergone an average of 4.2 surgeries and all required transankle fixation. The delayed-onset group had undergone an average of 1.5 surgeries, with one child requiring fixation across the ankle. Lack of ankle push-off and foot drop occurred in the early-onset group. Terminal stance phase ankle power generation was greatly diminished in the early-onset group. Total mechanical work performed by the affected limb, when compared to the uninvolved contralateral limb, was symmetric in delayed-onset patients and reduced by 68% in early-onset patients and by 85% in amputees. Gastrocsoleus strength was reduced by 40%. Gait and muscle strength of patients with“healed” congenital pseudarthrosis of the tibia are markedly disturbed. Early onset of disease, early surgery, and transankle fixation lead to an inefficient gait comparable to that of amputees.

Vasoactive intestinal peptide (VIP) is a neurotransmitter that has been identified in epicardial coronary arteries. To evaluate the direct effect of VIP on coronary hemodynamics and blood flow, graded doses of VIP (0.01, 0.03, 0.10, and 0.30 μgmin) were infused into the left coronary artery of 7 patients at the time of diagnostic cardiac catheterization for chest pain syndromes. None of the patients had coronary stenoses >50 during subsequent angiography. Coronary sinus VIP concentrations increased during each infusion (22 ± 28 pgml at baseline to 109 ± 22 pgml at 0.30 μgmin; p < 0.05), but arterial VIP was elevated (39 ± 29 pgml) only at the maximal dose of 0.30 μgmin. During all dosages of VIP, heart rate, right atrial and left ventricular end-diastolic pressure, and the heart rate × blood pressure product did not change. Moreover, neither mean aortic pressure nor left ventricular peak dPdt changed significantly at doses <0.30 μgmin; at 0.30 μgmin, mean aortic pressure decreased (97 ± 15 to 90 ± 15 mm Hg; p < 0.05) and LV peak dPdt increased (1,621 ± 230 to 1,801 ± 226 mm Hgs; p < 0.05). Compared to baseline, the arterial-coronary sinus O2content difference and myocardial O2extraction diminished progressively at the 0.03, 0.10, and 0.30 μgmin doses of VIP (118 ± 12 ml O2L vs. 94 ± 15, 70 ± 9, and 61 ± 26 ml O2L, respectively, and 0.64 ± 0.05 vs. 0.53 ± 0.10, 0.38 ± 0.06, and 0.34 ± 0.15, respectively). In the absence of hemodynamic alterations indicating a substantial variation in myocardial oxygen demand, these changes imply an increase in coronary blood flow and confirm that VIP has a direct effect on the coronary vasculature. These data support the concept that VIP may have a physiological role in the regulation of coronary resistance in man.

The TESOL Quarterlypublishes brief commentaries on aspects of English language teaching. For this issue, we asked two educators to discuss the following question: What is Ebonics, and is it relevant to TESOL?

Selection, hybridization, and genome manipulation in the Siluroidei is reviewed. Selection topics include strain evaluation, qualitative traits, quantitative traits, mass selection, family selection, inbreeding, and crossbreeding. Hybridization is discussed with reference to culture traits. Genome manipulation technologies-sex reversal, gynogenesis, androgenesis, polyploidization, and gene transfer-are considered with application to genetic improvement of Siluroidei. Strains of ictalurid catfish Vary significantly for traits such as growth, disease resistance, harvestability, reproduction, body conformation and carcass yield. Growth of domestic strains can be 250% greater than that of wild strains. Strain differences have also been identified for clariid, bagrid, and silurid catfishes. Mass selection has increascd growth rate by up to 30%. Heritability estimates predict a response to selection for the traits of disease resistance and tolerance to low oxygen levels. Crossbreeding strains of Ictalurus punctatus have improved growth, disease resistance and reproductive performance. Two generations of inbreeding depressed body weight of I. punctatus as much as 30%, and can reduce viability and reproductive performance. Hybridization of I. punctatus X I. furcatushas resulted in a 20% increase in growth. Traits for tolerance to oxygen deficit, feed conversion, disease resistance, harvestability, and carcass yield were also improved. Interspecific, intergeneric, and interfamilial hybrids have been made with clariid fishes; heterotic growth was indicated. Hybridization has also been used to combine desirable traits of parental species. Sex reversal of I. punctatus using estrogen treatment followed by progeny testing can result in monosex, all-male populations. Gynogenesis and androgenesis are approaches to production of inbred lines of catfish, but thus far have limited application in aquaculture. Polyploidization has been applied in several ictalurid, silurid, and clariid fishes, but predicted improvements in performance have not been realized. Gene transfer has been accomplished in I. punctatus and Clarias gariepinus using microinjection and electroporation; the foreign genes have been expressed and inherited. Transgenic I. punctatus containing salmonid growth hormone genes grew 20–40% faster than controls.

To examine the role of multidrug resistance protein 1 (MRP1) and glutathione S-transferases (GSTs) in cellular resistance to antineoplastic drugs, derivatives of MCF7 breast carcinoma cells were developed that express MRP1 in combination with one of three human cytosolic isozymes of GST. Expression of MRP1 alone confers resistance to several drugs representing the multidrug resistance phenotype, drugs including doxorubicin, vincristine, etoposide, and mitoxantrone. However, co-expression with MRP1 of any of the human GST isozymes A1-1, M1-1, or P1-1 failed to augment MRP1-associated resistance to these drugs. In contrast, combined expression of MRP1 and GST A1-1 conferred approximately 4-fold resistance to the anticancer drug chlorambucil. Expression of MRP1 alone failed to confer resistance to chlorambucil, showing that the observed protection from chlorambucil cytotoxicity was absolutely dependent upon GST A1-1 protein. Moreover, using inhibitors of GST (dicumarol) or MRP1 (sulfinpyrazone), it was shown that in MCF7 cells resistance to chlorambucil requires both intact MRP1-dependent efflux pump activity and, for full protection, GST A1-1 catalytic activity. These results are the first demonstration that GST A1-1 and MRP1 can act in synergy to protect cells from the cytotoxicity of a nitrogen mustard, chlorambucil.

Experimental infections of channel catfish virus were made by feeding virus to six strains of 1-, 2-, and 3-month-old channel catfish from different geographical areas and two hybrid strains. There was no significant difference in mortality between age groups. Mortality rates differed significantly between the various strains, with mean mortality ranging from 10% to 71% among infected fish. Mortality percentage of the Falcon group was significantly higher than all other groups. Hybrid strains had the lowest percentage of mortality.

The term "asbestosis" usually has been applied to a disease characterized by diffuse pulmonary interstitial fibrosis. It was often associated with a significant adverse impact on the individual. A review of case definitions employed in published research studies shows stability of the criteria for asbestosis case definitions over the past decade. Nevertheless, additional modalities have been suggested for the early diagnosis of asbestosis. It is probable that the significance of such abnormalities may be different from that of usual asbestosis, and there is therefore a need to carefully define the manner in which the terms are used. Additional anomalies way be seen in asbestos-exposed individuals including small airway physiologic abnormality, pathologic evidence of inflammation near the airways, positive gallium scan, abnormal lung compliance, exercise test abnormalities, CAT scan findings, and highresolution CAT scan findings.

Unstable angina pectoris as a distinct syndrome intermediate between chronic stable angina and acute myocardial infarction was first described about a half century ago. The incidence of death or myocardial infarction rises in the first few months after destabilization of angina. Hemodynamic, scintigraphic, and arteriographic studies in the last 15 years have shown that unstable angina is chiefly due to “dynamic” coronary stenoses, transient reversible limitations in coronary blood flow caused by a complex interaction between coronary vasoconstriction, transient platelet plugging, and transient thrombosis. The trigger for the onset of dynamic coronary stenoses is probably acute changes in coronary arterial morphology in or near atherosclerotic plaques making those areas more thrombogenic. A large fraction of patients with unstable angina restabilize initially with medical management. The role of beta blockers is unclear, but they may protect against development of coronary events for patients with unstable angina similar to that reported for patients with myocardial infarction. Nitrates and calcium blockers are probably superior to beta blockers in restabilization of angina, but protection against coronary events has not yet been demonstrated clearly. Further investigation is needed to distinguish the relative benefits of a two-drug (heart rate-limiting calcium blocker plus nitrates) regimen vs. a three-drug regimen including beta blocker. There is no basis for emergency coronary bypass surgery to prevent myocardial infarction or death. Urgent surgery should be limited to patients who do not stabilize readily with medical therapy. One third or more of the patients who initially restabilize with medical therapy will require coronary revascularization in the year after unstable angina because of severe angina. An antithrombotic regimen of aspirin (or possibly heparin) reduces the incidence of progression to death or myocardial infarction. Two important future directions for research should be promising: (1) development of better antithrombotic regimens other than aspirin alone for protection against coronary events; and (2) improved ability to distinguish the patients who initially respond to medical therapy who are at low risk for later severe angina from those at higher risk

The newly defined eicosatetraenoates (ETEs), 5-oxoETE and 5-oxo-15(OH)-ETE, share structural motifs, synthetic origins, and bioactions with leukotriene B4 (LTB4). All three eicosanoids stimulate Ca2+ transients and chemotaxis in human neutrophils (PMN). However, unlike LTB4, 5-oxoETE and 5-oxo-15(OH)-ETE alone cause little degranulation and no superoxide anion production. However, we show herein that, in PMN pretreated with granulocyte-macrophage or granulocyte colony-stimulating factor (GM-CSF or G-CSF), the oxoETEs become potent activators of the last responses. The oxoETEs also induce translocation of secretory vesicles from the cytosol to the plasmalemma, an effect not requiring cytokine priming. To study the mechanism of PMN activation in response to the eicosanoids, we examined the activation of mitogen-activated protein kinase (MAPK) and cytosolic phospholipase A2 (cPLA2). PMN expressed three proteins (40, 42, and 44 kDa) that reacted with anti-MAPK antibodies. The oxoETEs, LTB4, GM-CSF, and G-CSF all stimulated PMN to activate the MAPKs and cPLA2, as defined by shifts in these proteins' electrophoretic mobility and tyrosine phosphorylation of the MAPKs. However, the speed and duration of the MAPK response varied markedly depending on the stimulus. 5-OxoETE caused a very rapid and transient activation of MAPK. In contrast, the response to the cytokines was rather slow and persistent. PMN pretreated with GM-CSF demonstrated a dramatic increase in the extent of MAPK tyrosine phosphorylation and electrophoretic mobility shift in response to 5-oxoETE. Similarly, 5-oxoETE induced PMN to release some preincorporated [14C]arachidonic acid, while GM-CSF greatly enhanced the extent of this release. Thus, the synergism exhibited by these agents is prominent at the level of MAPK stimulation and phospholipid deacylation. Pertussis toxin, but not Ca2+ depletion, inhibited MAPK responses to 5-oxoETE and LTB4, indicating that responses to both agents are coupled through G proteins but not dependent upon Ca2+ transients. 15-OxoETE and 15(OH)-ETE were inactive while 5-oxo-15(OH)-ETE and 5(OH)-ETE had 3- and 10-fold less potency than 5-oxoETE, indicating a rather strict structural specificity for the 5-keto group. LY 255283, a LTB4 antagonist, blocked the responses to LTB4 but not to 5-oxoETE. Therefore, the oxoETEs do not appear to operate through the LTB4 receptor. In summary, the oxoETEs are potent activators of PMN that share some but not all activities with LTB4. The response to the oxoETEs is greatly enhanced by pretreatment with cytokines, indicating that combinations of these mediators may be very important in the pathogenesis of inflammation.

Pure-strain and interstrain (crossbred) channel catfish Ictalurus punctatus were compared for spawning day, spawning rate (percent of replicate pairs that spawned), fecundity, egg size and hatchability, and survival of offspring. Crossbred fish usually spawned earlier (P < 0.05) than pure-strain channel catfish. As 3-year-olds, crossbred fish had higher spawning rates and fecundity than purebred fish, and their output of juveniles (number surviving 45 days in ponds, per kilogram of female parent) was greater. As 4-year-olds, pure-strain fish improved their performances, and crossbreds lost most of their relative advantages. Brood stock derived from crosses of four strains spawned earlier than those from two-strain F2crosses, but their surviving offspring were no more numerous. The main value of cross-strain breeding is to produce channel catfish that mature earlier in life and spawn sooner in the season than purebreds. Received July 16, 1982 Accepted March 4, 1983

Heritability estimates and genetic and phenotypic correlations were determined for length and weight at 45 and 90 days in the Auburn strain of Tilapia nilotica. Heritability estimates were determined by half-sib analysis from an experiment that contained 16 paternal half-sib families or 32 full-sib families, that is, two full-sib families nested in each of 16 paternal half-sib families. Average length and weight were 63 mm and 4.9 g at 45 days, and 99 mm and 18.6 g at 90 days. Sire heritability estimates ranged frown 0.04 to 0.10, and dam heritability estimates ranged from -0.02 to 0.54. Dam heritability for length at 45 days was the only heritability estimate that was significantly different frown zero (P = 0.05). At 45 days, environmental and dominance genetic variance were the major contributors to phenotypic variance, while at 90 days environmental variance accounted for virtually all of the phenotypic variance. Genetic and phenotypic correlations between length and weight at 45 and 90 days ranged from 0.94 to 1.12. Predicted gains from mass selection were small because of low heritabilities and small standard deviations. Low genetic variation may have been caused by drastic reductions in the effective breeding number during transfer of the fish stocks from the Ivory Coast to Brazil and from Brazil to Auburn. Problems caused by reduction of genetic variance as a result of reductions in effective breeding number are discussed.

Mass selection for rapid and slow early growth was applied for one generation to 58-d-old Nile tilapia Tilapia nilotica(Ivory Coast strain). Realized heritability (±SE) for rapid growth was –0.10 ± 0.02, and mean body weight of progeny was not different (P> 0.05) from that of control fish. This confirms an earlier prediction from half-sib analysis of the same stock that selection for rapid growth would be ineffective for these fish (half-sib heritabilities were 0.04 ± 0.14 at age 45 d and 0.04 ± 0.06 at age 90 d). In contrast, selection for slow early growth resulted in realized heritability of 0.36 ± 0.08, and mean body weight of progeny was less than that of control fish (P< 0.05). Our study indicated that an upper limit to growth enhancement by selection exists in this stock of T. nilotica, probably due to a small founder stock, subsequent reductions in effective breeding numbers, and 8 years of domestication. We conclude that half-sib analysis can be an efficient means for estimating the effectiveness of mass selection.

Model cell lines developed from MCF7 breast carcinoma cells were used to examine the roles of glutathione S-transferase P1-1 (GSTP1-1) and multidrug resistance protein (MRP) in the protection of cells from 4-nitroquinoline 1-oxide (4NQO) toxicities. Increased expression of GSTP1-1 alone in MCF7 cells resulted in limited protection from the formation of 4NQO-derived covalent adducts of nucleic acids but affords no protection from 4NQO-mediated cytotoxicity. Increased expression of MRP alone conferred modest protection while co-expression of GSTP1-1 with MRP produced high-level protection from both 4NQO-derived adduct formation and 4NQO cytotoxicity. This synergistic resistance to 4NQO toxicities (both nucleic acid adduct formation and cytotoxicity) is associated with a GSTP1-1-dependent increase in 4NQO-glutathione (QO-SG) conjugate formation and a MRP-dependent increase in QO-SG efflux. These data indicate that MRP is an important export transporter for the glutathione conjugate of the carcinogen, 4NQO. Moreover, this MRP-dependent efflux activity is necessary to achieve the full protection from 4NQO toxicity-protection that is potentiated by GSTP1-1-mediated QO-SG formation.

The term “asbestosis” usually has been applied to a disease characterized by diffuse pulmonary interstitial fibrosis. It was often associated with a significant adverse impact on the individual. A review of case definitions employed in published research studies shows stability of the criteria for asbestosis case definitions over the past decade. Nevertheless, additional modalities have been suggested for the early diagnosis of asbestosis. It is probable that the significance of such abnormalities may be different from that of usual asbestosis, and there is therefore a need to carefully define the manner in which the terms are used. Additional anomalies may be seen in asbestosexposed individuals including small airway physiologic abnormality, pathologic evidence of inflammation near the airways, positive gallium scan, abnormal lung compliance, exercise test abnormalities, CAT scan findings, and highresolution CAT scan findings.

The article focuses on the importance of language in the formation of ideology, consciousness, behavior and social relations. It discusses a theory of language developed within the framework of social and revolutionary transformation based of the linguistic situation in the U.S. It notes how language can mark power relationships. It stresses that negative social meanings and class-biased language tend to sound natural and common due to repetitive use and social reinforcement.

The lateral transpsoas interbody fusion (LTIF) is an increasingly popular minimally invasive technique for lumbar interbody fusion. Although a posterior approach to the lumbar spine has traditionally been favored for the treatment of canal stenosis and neural foraminal stenosis, a growing body of evidence suggests that indirect decompression of the spinal canal and neural foramen can be achieved using a lateral transpsoas approach to the lumbar spine. We present 2 cases that may suggest a role for spontaneous electromyography (s-EMG) monitoring in assessing the adequacy of decompression during LTIF.

A model studied earlier in relation to aqueous 1–1 electrolytes has been applied to the interpretation of the excess free energies of aqueous solutions of the alkaline earth halides up to 1 M ionic strength. Several variations on the model could be fitted to the data. In the one which seems most consistent with the other observations, the cospheres (hydration layers) on the M++ ions were two water molecules thick rather than one as for the alkali metal, tetraalkylammonium, and halide ions. The overlap of cospheres of an M++, M++ pair was found to make a small attractive contribution to the interionic force, while the overlap of cospheres of an M++, X- pair makes a small positive contribution which is almost the same for X-=Cl-, Br-, or I-. Thus, ionic hydration shells which are not penetrated by other ions are not required to account for the observed excess free energies. The model is also fitted to NaCl-MgCl2 mixtures to see whether the new cosphereoverlap parameter which must be determined is consistent with the others. The calculation also shows how the thermodynamic behavior of the mixtures is consistent with the mixture limiting law for unsymmetrical mixtures. The singularities in the mixing coefficients g0 and w0 at infinite dilution dominate their concentration dependence only up to ionic strengths of about 0.01 M in models which fit the data.

NMR spectra reveal a ring current in substituted 4-pyrones which is not substantiated by magnetic susceptibility data. IR, polarographic, and hydrogen bonding data on 2,6-diaryl-4-pyrones are correlated with Hammett substituent constants.

A radiation‐induced transfer of hydrogen from exchangeable to carbon‐bound sites occurs in nucleic acids, proteins and their constituents. The G‐values for this process are similar within a factor of 2–3 to the G‐values for the initial production of stable radicals measured by ESR at room temperature. Unlike the production of radicals, hydrogen transfer in ribonuclease, DNA, and thymine is a linear function of dose in the 0–30 Megarad region. The tritium distributions obtained in proteins by hydrogen transfer are not a measure of the distribution of the “secondary” radicals. From the studies of the effect of temperature, of various scavengers (particularly nitric oxide) and of the dose dependence in the low dose region, it was inferred that for ribonuclease most of the hydrogen transfer takes place during the conversion of the radicals stable at 195°K to the radicals stable at room temperature. The same mechanism also appears to predominate in DNA.

All possible crosses among three species of sunfishes—the bluegill, Lepomis macrochirus Rafinesque; the redear, Lepomis microlophus (Günther); and the redbreast, Lepomis auritus (Linnaeus)—were successfully produced. One cross, female redbreast X male bluegill, was made by placing one adult of each species in a plastic pool and allowing them to spawn. The five remaining crosses were produced two to nine times each by stripping and artificial insemination. Progeny from five of the six possible crosses were stocked in plastic and/or concrete pools and allowed to grow for approximately 2 months. Samples from each cross were examined, and 10 meristic counts were recorded for each fish. Corresponding counts were made on samples from each parent species. The data provide characterizations of parent species and their hybrids as well as comparisons among them. The comparisons showed that hybrids were generally intermediate between their parent species in most taxonomic characters. A blending or multiple allelic inheritance rather than simple Mendelian inheritance was indicated in the determination of these characters. Other sunfish crosses were successfully made, but the progeny were not reared. The fertility of hybrid males from the F1cross of female bluegill X male redbreast was established in crosses with female green sunfish, Lepomis cyanellus Rafinesque, female bluegill, and female redear. Reciprocal crosses between the green sunfish and redear were made. Female green sunfish were also successfully crossed with a male redbreast and with a male bluegill.

The article celebrates the life and career of LeRoy Franklin Saunders, the president of the American Council of the Blind (ACB) who died in 2012.

The article presents several letters to the editor including one that responds to the article "Disas of the fynbos," one that tells about the sender's experience of visiting the West Coast, and one that talks about a bag made with genetically modified-free renewable corn starch.

The present study undertook to discover whether individuals would lie to help someone as a function of the size of the lie and the need or dependency of the person needing help. Subjects were confronted with an opportunity to help another person (a confederate of the researcher) by agreeing to his judgments of the distance which a point of light moved in an otherwise dark room. Although the light was stationary, the confederate made guesses ranging between 0 and 26 in. The results indicate that the size of the lie had little effect on whether the subject helped but the subject did not help when the confederate had nothing to lose. The subjects appeared willing to lie when it would help another person.