Parthenogenesis in a whitetip reef shark Triaenodon obesus involves a reduction in ploidy

Genetic analysis of a female whitetip reef shark Triaenodon obesus and her stillborn pup, assumed to be of parthenogenetic origin, revealed that the pup was homozygous at all 24 nuclear-encoded microsatellites assayed, consistent with the idea that diploidy in the pup had been restored via terminal fusion. Flow cytometric analysis, however, indicated that the genome size of the pup was no more than half that of the mother, and microscopy revealed that nuclear volume was c. 1.73 times larger in the mother than in the pup. Together these data suggest that the pup was genetically haploid, developing directly from an unfertilized egg; as far as is known, this is the first observation of a spontaneously produced haploid vertebrate.

Standard pentostatin dose reductions in renal insufficiency are not adequate: selected patients with steroid-refractory acute graft-versus-host disease

BACKGROUND AND OBJECTIVE

Pentostatin is an irreversible inhibitor of adenosine deaminase and has been used to prevent graft-versus-host disease (GVHD) and to treat both acute and chronic GVHD. Dose reduction equations for patients with renal insufficiency are based on few patients with limited pharmacokinetic and clinical results. This phase II study (NCT00201786) was conducted to assess pentostatin efficacy and infectious complications seen from our previous phase I study in steroid-refractory acute GVHD (aGVHD).

PATIENTS AND METHODS

Hospitalized patients with steroid-refractory aGVHD were given pentostatin 1.5 mg/m(2)/day intravenously on days 1-3 of each 14-day cycle. Prior to each dose, dose modifications were based on Cockcroft-Gault estimated creatinine clearance (eCrCL) with 30-50 mL/min/1.73 m(2) leading to a 50 % dose reduction and eCrCL less than 30 mL/min/1.73 m(2) leading to study removal. Plasma pentostatin area under the concentration-time curve (AUC) and incidence of infectious complications were evaluated.

RESULTS

Two of the eight patients treated demonstrated excessive pentostatin exposure as determined by measurement of AUC. One of these patients had renal impairment, whereas the other patient demonstrated borderline renal function. Despite dose reduction to 0.75 mg/m(2), AUCs were significantly increased compared to the other patients in this study. Seven of eight patients treated with pentostatin had cytomegalovirus (CMV) viremia after pentostatin treatment; however none developed proven CMV disease.

CONCLUSION

A 50 % dose reduction in patients with eCrCL 30-50 mL/min/1.73 m(2) seems reasonable. However, the eCrCL should be interpreted with extreme caution in patients who are critically ill and/or with poor performance status. Renal function assessment based on the Cockcroft-Gault method could be significantly overestimated thus risking pentostatin overdosing. These results imply a need to closely monitor pentostatin exposure in patients with renal insufficiency.

Genome size and ploidy of Thysanoptera

Flow cytometry was used to study the genome sizes and ploidy levels for four thrips species: Franklinothrips orizabensis Johansen (Thysanoptera: Aeolothripidae), Frankliniella occidentalis Pergande, Frankliniella fusca Hinds, and Thrips tabaci Lindeman (Thysanoptera: Thripidae). F. orizabensis males and females had 1C genome sizes of 426 Mb and 422 Mb, respectively. Male and female F. fusca had 1C genome sizes of 392 Mb and 409 Mb, whereas F. occidentalis males and females had smaller 1C genomes that were 345 Mb and 337 Mb, respectively. Male F. orizabensis, F. occidentalis and F. fusca were haploid and females diploid. Five isofemale lines of T. tabaci, initiated from parthenogenetic, thelytokous females and collected from different locations in North Carolina, were included in this study; no males were available. One isofemale line was diploid with a genome size of 1C = 310 Mb, and the other four had a mean genome size of 1C = 482 Mb, which is consistent with evidence from microsatellite data of diploidy and polyploidy, respectively, in these same five thelytokous lines. This is the first study to produce genome size estimates for thysanopteran species, and report polyploidy in T. tabaci populations.

Genome size and ploidy of Thysanoptera

Flow cytometry was used to study the genome sizes and ploidy levels for four thrips species: Franklinothrips orizabensis Johansen (Thysanoptera: Aeolothripidae), Frankliniella occidentalis Pergande, Frankliniella fusca Hinds, and Thrips tabaci Lindeman (Thysanoptera: Thripidae). F. orizabensis males and females had 1C genome sizes of 426 Mb and 422 Mb, respectively. Male and female F. fusca had 1C genome sizes of 392 Mb and 409 Mb, whereas F. occidentalis males and females had smaller 1C genomes that were 345 Mb and 337 Mb, respectively. Male F. orizabensis, F. occidentalis and F. fusca were haploid and females diploid. Five isofemale lines of T. tabaci, initiated from parthenogenetic, thelytokous females and collected from different locations in North Carolina, were included in this study; no males were available. One isofemale line was diploid with a genome size of 1C = 310 Mb, and the other four had a mean genome size of 1C = 482 Mb, which is consistent with evidence from microsatellite data of diploidy and polyploidy, respectively, in these same five thelytokous lines. This is the first study to produce genome size estimates for thysanopteran species, and report polyploidy in T. tabaci populations.

Pharmacokinetics and dose escalation of the heat shock protein inhibitor 17-allyamino-17-demethoxygeldanamycin in combination with bortezomib in relapsed or refractory acute myeloid leukemia

Abstract This phase I study was conducted to determine the maximum tolerated dose (MTD) and dose limiting toxicities (DLTs) of the heat shock protein 90 (HSP90) inhibitor 17-allyamino-17-demethoxygeldanamycin (17-AAG) in combination with bortezomib, and to provide pharmacokinetic data in relapsed or refractory acute myeloid leukemia (AML). Eleven patients were enrolled. The MTD was 17-AAG 150 mg/m(2) and bortezomib 0.7 mg/m(2). Hepatic toxicity and cardiac toxicity were dose limiting. Co-administration on day 4 led to a decrease in clearance (p = 0.005) and increase in AUC (p = 0.032) of 17-amino-17-demethoxygeldanamycin (17-AG), not observed when 17-AAG was administered alone. Pharmacokinetic parameters of patients who developed toxicities and those who did not were not different. The combination of 17-AAG and bortezomib led to toxicity without measurable response in patients with relapsed or refractory AML. Pharmacokinetic data provide insight for studies of related agents in AML. Next-generation HSP90 inhibitors are appealing for further development in this area.

Genome sizes of forensically relevant Diptera

Genome size estimates for both sexes of forensically relevant Diptera from 17 species (four families) are reported herein. Average genome sizes ranged from 425.8 Mb for female Chrysomya rufifacies to 1,197.4 Mb for male Haematobia irritans. These estimates are useful not only for molecular studies, but also for determination of the species and sex of immatures. Species in three of the sampled families had sexually dimorphic genome sizes, presenting a new tool useful for the determination of sex in these species, especially in the immature stages where sexes are morphologically difficult or impossible to identify. In addition, closely related species had significantly different genome sizes, suggesting the use of flow cytometry as a new tool for species identification of some species of forensically relevant larvae.

Phase 2 trial of rituximab and bortezomib in patients with relapsed or refractory mantle cell and follicular lymphoma

BACKGROUND

In vitro studies in mantle cell lymphoma (MCL) cell lines and patient-derived cells have demonstrated synergistic apoptosis with combined rituximab and bortezomib (R-bortezomib) compared with single-agent bortezomib. Therefore, the authors of this report evaluated R-bortezomib in a preclinical model and in a phase 2 clinical trial.

METHODS

A Hu-MCL-severe combined immunodeficiency (SCID) model engrafted with the Jeko cell line was treated with R-bortezomib, bortezomib, or rituximab. Twenty-five patients with relapsed follicular lymphoma (n = 11) and MCL (n = 14) received 375 mg/m(2) rituximab on Days 1 and 8 and 1.3 to 1.5 mg/m(2) bortezomib on Days 1, 4, 8, and 11 every 21 days for a median of 3 cycles (range, 1-5 cycles).

RESULTS

R-bortezomib resulted in a statistically significant improvement in overall survival in Hu-MCL-SCID mice. In the clinical trial, the overall response rate was 40% in all 25 patients, 55% in patients with follicular lymphoma, and 29% in patients with MCL. The estimated 2-year progression-free survival (PFS) rate was 24% (95% confidence interval [CI], 10%-53%) in all patients and 60% (95% CI, 20%-85%) in responding patients. Thirteen patients (52%) developed grade 3 neurotoxicity, which consisted of constipation/ileus, sensory or motor neuropathy, or orthostatic hypotension. Patients who were heterozygous for the CD32a (Fcγ receptor IIa) 131 histidine (H) to arginine (R) polymorphism had a significantly decreased PFS (P = .009) after R-bortezomib compared with HH and RR homozygotes.

CONCLUSIONS

R-bortezomib had significant activity in patients with relapsed or refractory follicular lymphoma and MCL, although an unexpectedly high incidence of grade 3 neurologic toxicity was a potential limiting factor with this combination.

Combination bortezomib and rituximab treatment affects multiple survival and death pathways to promote apoptosis in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a distinct histologic subtype of B cell non-Hodgkins lymphoma (NHL) associated with an aggressive clinical course. Inhibition of the ubiquitin-proteasome pathway modulates survival and proliferation signals in MCL and has shown clinical benefit in this disease. This has provided rationale for exploring combination regimens with B-cell selective immunotherapies such as rituximab. In this study, we examined the effects of combined treatment with bortezomib and rituximab on patient-derived MCL cell lines (Jeko, Mino, SP53) and tumor samples from patients with MCL where we validate reversible proteasome inhibition concurrent with cell cycle arrest and additive induction of apoptosis. When MCL cells were exposed to single agent bortezomib or combination bortezomib/rituximab, caspase dependent and independent apoptosis was observed. Single agent bortezomib or rituximab treatment of Mino and Jeko cell lines and patient samples resulted in decreased levels of nuclear NFkappaB complex(es) capable of binding p65 consensus oligonucleotides, and this decrease was enhanced by the combination. Constitutive activation of the Akt pathway was also diminished with bortezomib alone or in combination with rituximab. On the basis of in vitro data demonstrating additive apoptosis and enhanced NFkappaB and phosphorylated Akt depletion in MCL with combination bortezomib plus rituximab, a phase II trial of bortezomib-rituximab in patients with relapsed/refractory MCL is underway.

A genotyping exercise for pharmacogenetics in pharmacy practice

OBJECTIVE

To develop a genotype exercise to improve pharmacy students' comprehension of pharmacogenetic principles that apply to patient care.

DESIGN

Deoxyribonucleic acid (DNA) was collected during class from 10 student volunteers and subjected to genotype analysis. The results were presented to the class and discussed in the context of a patient genetic counseling session. Students completed a survey instrument regarding their attitudes toward this learning experience.

ASSESSMENT

Students indicated that the exercise engaged them with the course content and would positively influence their ability to apply pharmacogenetic principles to patient care.

CONCLUSION

An applied genotype exercise enhanced learning of pharmacogenetic principles. Based on these findings, conducting a genotype exercise in a large classroom setting is feasible in terms of time and expense, and meaningful in terms of student satisfaction.

Development and validation of a sensitive liquid chromatography/mass spectrometry method for quantitation of flavopiridol in plasma enables accurate estimation of pharmacokinetic parameters with a clinically active dosing schedule

A high-performance liquid chromatographic assay with tandem mass spectrometric detection was developed and validated for quantitation of the broad spectrum kinase inhibitor, flavopiridol, in human plasma. Sample preparation conditions included liquid-liquid extraction in acetonitrile (ACN), drying, and reconstitution in 20/80 water/ACN. Flavopiridol and the internal standard (IS), genistein, were separated by reversed phase chromatography using a C-18 column and a gradient of water with 25 mM ammonium formate and ACN. Electrospray ionization and detection of flavopiridol and genistein were accomplished with single reaction monitoring of m/z 402.09>341.02 and 271.09>152.90, respectively in positive-ion mode [M+H](+) on a triple quadrupole mass spectrometer. Recovery was greater than 90% throughout the linear range of 3-1000 nM. Replicate sample analysis indicated within- and between-run accuracy and precision to be less than 13% throughout the linear range. This method has the lowest lower limit of quantitation (LLOQ) reported to date for flavopiridol, and it allows for more accurate determination of terminal phase concentrations and improved pharmacokinetic parameter estimation in patients receiving an active dosing schedule of flavopiridol.

Sequencing of a new target genome: the Pediculus humanus humanus (Phthiraptera: Pediculidae) genome project

The human body louse, Pediculus humanus humanus (L.), and the human head louse, Pediculus humanus capitis, belong to the hemimetabolous order Phthiraptera. The body louse is the primary vector that transmits the bacterial agents of louse-borne relapsing fever, trench fever, and epidemic typhus. The genomes of the bacterial causative agents of several of these aforementioned diseases have been sequenced. Thus, determining the body louse genome will enhance studies of host-vector-pathogen interactions. Although not important as a major disease vector, head lice are of major social concern. Resistance to traditional pesticides used to control head and body lice have developed. It is imperative that new molecular targets be discovered for the development of novel compounds to control these insects. No complete genome sequence exists for a hemimetabolous insect species primarily because hemimetabolous insects often have large (2000 Mb) to very large (up to 16,300 Mb) genomes. Fortuitously, we determined that the human body louse has one of the smallest genome sizes known in insects, suggesting it may be a suitable choice as a minimal hemimetabolous genome in which many genes have been eliminated during its adaptation to human parasitism. Because many louse species infest birds and mammals, the body louse genome-sequencing project will facilitate studies of their comparative genomics. A 6-8X coverage of the body louse genome, plus sequenced expressed sequence tags, should provide the entomological, evolutionary biology, medical, and public health communities with useful genetic information.

Characteristics of the nuclear (18S, 5.8S, 28S and 5S) and mitochondrial (12S and 16S) rRNA genes of Apis mellifera (Insecta: Hymenoptera): structure, organization, and retrotransposable elements

As an accompanying manuscript to the release of the honey bee genome, we report the entire sequence of the nuclear (18S, 5.8S, 28S and 5S) and mitochondrial (12S and 16S) ribosomal RNA (rRNA)-encoding gene sequences (rDNA) and related internally and externally transcribed spacer regions of Apis mellifera (Insecta: Hymenoptera: Apocrita). Additionally, we predict secondary structures for the mature rRNA molecules based on comparative sequence analyses with other arthropod taxa and reference to recently published crystal structures of the ribosome. In general, the structures of honey bee rRNAs are in agreement with previously predicted rRNA models from other arthropods in core regions of the rRNA, with little additional expansion in non-conserved regions. Our multiple sequence alignments are made available on several public databases and provide a preliminary establishment of a global structural model of all rRNAs from the insects. Additionally, we provide conserved stretches of sequences flanking the rDNA cistrons that comprise the externally transcribed spacer regions (ETS) and part of the intergenic spacer region (IGS), including several repetitive motifs. Finally, we report the occurrence of retrotransposition in the nuclear large subunit rDNA, as R2 elements are present in the usual insertion points found in other arthropods. Interestingly, functional R1 elements usually present in the genomes of insects were not detected in the honey bee rRNA genes. The reverse transcriptase products of the R2 elements are deduced from their putative open reading frames and structurally aligned with those from another hymenopteran insect, the jewel wasp Nasonia (Pteromalidae). Stretches of conserved amino acids shared between Apis and Nasonia are illustrated and serve as potential sites for primer design, as target amplicons within these R2 elements may serve as novel phylogenetic markers for Hymenoptera. Given the impending completion of the sequencing of the Nasonia genome, we expect our report eventually to shed light on the evolution of the hymenopteran genome within higher insects, particularly regarding the relative maintenance of conserved rDNA genes, related variable spacer regions and retrotransposable elements.

Assessing the odd secondary structural properties of nuclear small subunit ribosomal RNA sequences (18S) of the twisted-wing parasites (Insecta: Strepsiptera)

We report the entire sequence (2864 nts) and secondary structure of the nuclear small subunit ribosomal RNA (SSU rRNA) gene (18S) from the twisted-wing parasite Caenocholax fenyesi texensis Kathirithamby & Johnston (Strepsiptera: Myrmecolacidae). The majority of the base pairings in this structural model map on to the SSU rRNA secondary and tertiary helices that were previously predicted with comparative analysis. These regions of the core rRNA were unambiguously aligned across all Arthropoda. In contrast, many of the variable regions, as previously characterized in other insect taxa, had very large insertions in C. f. texensis. The helical base pairs in these regions were predicted with a comparative analysis of a multiple sequence alignment (that contains C. f. texensis and 174 published arthropod 18S rRNA sequences, including eleven strepsipterans) and thermodynamic-based algorithms. Analysis of our structural alignment revealed four unusual insertions in the core rRNA structure that are unique to animal 18S rRNA and in general agreement with previously proposed insertion sites for strepsipterans. One curious result is the presence of a large insertion within a hairpin loop of a highly conserved pseudoknot helix in variable region 4. Despite the extraordinary variability in sequence length and composition, this insertion contains the conserved sequences 5'-AUUGGCUUAAA-3' and 5'-GAC-3' that immediately flank a putative helix at the 5'- and 3'-ends, respectively. The longer sequence has the potential to form a nine base pair helix with a sequence in the variable region 2, consistent with a recent study proposing this tertiary interaction. Our analysis of a larger set of arthropod 18S rRNA sequences has revealed possible errors in some of the previously published strepsipteran 18S rRNA sequences. Thus we find no support for the previously recovered heterogeneity in the 18S molecules of strepsipterans. Our findings lend insight to the evolution of RNA structure and function and the impact large insertions pose on genome size. We also provide a novel alignment template that will improve the phylogenetic placement of the Strepsiptera among other insect taxa.

Interspecies differences in pharmacokinetics and metabolism of S-3-(4-acetylamino-phenoxy)-2-hydroxy-2-methyl-N-(4-nitro-3-trifluoromethylphenyl)-propionamide: the role of N-acetyltransferase

N-Acetyltransferase (NAT) is one of the major phase II enzymes involved in drug metabolism. Both species differences and polymorphism are observed in NAT expression. During the preclinical development of a novel selective androgen receptor modulator, S-3-(4-acetylamino-phenoxy)-2-hydroxy-2-methyl-N-(4-nitro-3-trifluoromethyl-phenyl)-propionamide (S4), we also observed species differences in S4 metabolism due to the interaction between the deacetylation metabolite M1 and NAT, which converted M1 back to S4 both in vitro and in vivo. During incubation with human liver cytosol or rat liver S9 fraction in the presence of acetyl-CoA, more than 50% of M1 (2 microM) was converted back to S4, but this conversion was not observed in the incubation with dog liver S9 fraction or human liver microsome. In vivo pharmacokinetic experiments showed that M1 could be rapidly converted back to S4 in rats, but a similar conversion was not observed in dogs. When S4 was administered, the formation of M1 was only observed in dogs due to the absence of NAT expression. Simultaneous fitting of the concentration-time profiles of both S4 and M1 showed that more than 50% of S4 was deacetylated to M1 in dogs after i.v. administration of S4, whereas more than 80% of M1 was converted to S4 in rats after i.v. administration of M1. Considering the polymorphism in NAT expression, the interaction between M1 and NAT may raise concerns for drug-drug interactions during clinical applications of S4. The observed species differences suggested that interspecies scaling might not be applicable for predicting the metabolism and disposition of S4 in humans.

In vitro and pharmacophore-based discovery of novel hPEPT1 inhibitors

PURPOSE

The human proton-coupled small peptide carrier (hPEPT1) is a low-affinity, high-capacity transporter with broad substrate specificity. We have taken an iterative in vitro and in silico approach to the discovery of molecules with hPEPT1 affinity.

METHODS

A pharmacophore-based approach was taken to identifying hPEPT1 inhibitors. The well-characterized and relatively high affinity ligands Gly-Sar, bestatin, and enalapril were used to generate a common features (HIPHOP) pharmacophore. This consisted of two hydrophobic features, a hydrogen bond donor, acceptor, and a negative ionizable feature.

RESULTS

The pharmacophore was used to search the Comprehensive Medicinal Chemistry (CMC) database of more than 8000 drug-like molecules and retrieved 145 virtual hits mapping to the pharmacophore features. The highest scoring compounds within this set were selected and tested in a stably transfected CHO-hPepT1 cell model. The antidiabetic repaglinide and HMG CoA reductase inhibitor fluvastatin were found to inhibit hPEPT1 with sub-millimolar potency (IC(50) 178 +/- 1.0 and 337 +/- 4 microM, respectively). The pharmacophore was also able to identify known hPEPT1 substrates and inhibitors in further database mining of more than 500 commonly prescribed drugs.

CONCLUSIONS

This study demonstrates the potential of combining computational and in vitro approaches to determine the affinity of compounds for hPEPT1 and, in turn, provides insights into key molecular interactions with this transporter.

Tiny genomes and endoreduplication in Strepsiptera

Using flow cytometry, the genome sizes of two species of Strepsiptera were studied: that of male Caenocholax fenyesi texensis Kathirithamby & Johnston (Myrmecolacidae) at 108 Mb, which is the smallest insect genome documented to date; and those of male and female Xenos vesparum Rossi (Stylopidae), which are 1C = 130 and 133 Mb, respectively. The genome sizes of the following were analysed for comparative purposes: (a) the Hessian fly, Mayetiola destructor (Say), which was previously reported to be the smallest among insects: the male measured at 1C = 121 Mb and the female at 1C = 158 Mb; and (b) the female parasitic, haplodiploid, microhymenopteran wasp, Trichogramma brassicae Bezdenko, which measured at 1C = 246 Mb. The hosts of the strepsipterans were also measured: male Solenopsis invicta Buren, the red imported fire ant (host of male C. f. texensis), which is 1C = 753.3 Mb, and female Polistes dominulus Christ, the paper wasp (host of X. vesparum), is 1C = 301.4 Mb. Endoreduplication (4C) of the genome of the thorax of the male strepsipteran, and higher levels of endoduplication (4, 8, 16C) in the body of the larger female was observed. In contrast, little or no endoreduplication was observed, either in the Hessian fly, or in the parasitic wasp.

Synergy between 3'-azido-3'-deoxythymidine and paclitaxel in human pharynx FaDu cells

PURPOSE

We recently demonstrated simultaneous targeting of telomere and telomerase as a novel cancer therapeutic approach, and that telomerase inhibitors such as 3'-azido-3'-deoxythymidine (AZT) significantly enhanced the antitumor activity of paclitaxel, which causes telomere erosion, in telomerase-positive human pharynx FaDu tumors in vitro and in vivo. The present study evaluated the synergy between AZT and paclitaxel to identify optimal combinations for future clinical evaluation.

METHODS

FaDu cells were incubated with or without AZT for 24 h and then treated with AZT with or without paclitaxel for an additional 48 h. Under these conditions, single agent paclitaxel produced a 60% maximum reduction of cell number (IC50) was 7.3 nM), and single agent AZT produced a 97% reduction (IC50 was 5.6 microM). Synergy was evaluated using fixed-concentration and fixed-ratio methods, and data were analyzed by the combination index method.

RESULTS

The results indicate a concentration-dependent synergy between the two drugs; the synergy was higher for combinations containing greater paclitaxel-to-AZT concentration ratios and increased with the level of drug effect. For example, in combinations containing 1 microM AZT, synergy was 1.3-fold at the 20% effect level and 3.1-fold at the 60% effect level. Because the major antitumor activity, determined by comparing the posttreatment cell number to the pretreatment cell number, was antiproliferation at the 20% effect level and cell kill at the 60% effect level, our results suggest that AZT mainly enhances the cell kill effect of paclitaxel.

CONCLUSION

In summary, the present study demonstrates a synergistic interaction between paclitaxel and AZT and supports a combination using a low and nontoxic AZT dose in combination with a therapeutically active dose of paclitaxel.

Nietzsche and the dilemma of suffering

In this paper, we attempt to view a long-held assumption in nursing as mistaken. That is, that patient suffering is something to be overcome. Utilizing Nietzsche's statements on Amor Fati, we carefully examine the cultural assumptions behind our denigration of suffering, look at specific nursing examples of this situation, and attempt the beginnings of a discourse on what it would take for nurses to overcome their own predetermined views of suffering in order to better help their patients "own" their own suffering.

Evidence for DNA loss as a determinant of genome size

Eukaryotic genome sizes range over five orders of magnitude. This variation cannot be explained by differences in organismic complexity (the C value paradox). To test the hypothesis that some variation in genome size can be attributed to differences in the patterns of insertion and deletion (indel) mutations among organisms, this study examines the indel spectrum in Laupala crickets, which have a genome size 11 times larger than that of Drosophila. Consistent with the hypothesis, DNA loss is more than 40 times slower in Laupala than in Drosophila.

Recombinant anti-polyamine antibodies: identification of a conserved binding site motif

Polyamines are small linear polycations found ubiquitously in eukaryotic cells. They are involved in nucleic acid and protein synthesis and rises in cellular polyamine levels have been correlated with cell proliferation. Antibodies to these molecules have potential as prognostic indicators of disease conditions and indicators of treatment efficacy. Antipolyamine monoclonal antibodies of differing but defined specificities have been generated in our laboratory using polyamine ovalbumin conjugates as immunogens. These antibodies show small but significant cross reactivities with other polyamine species; IAG-1 cross reacts with spermidine (8%), JAC-1 with spermine (6%) and JSJ-1 with both putrescine (11%) and spermine (6%). We have rescued and sequenced the heavy and light chain variable regions of all three of these antibodies. While the light chains of two antibodies, IAG-1 and JSJ-1, were 93% homologous at the amino acid level, none of the heavy chains displayed any significant sequence homology. However, computer-generated models of all three antibody binding sites revealed a three-dimensionally conserved polyamine binding site motif. The polyamine appears to bind into a negatively charged cleft lined with acidic and polar residues. The cleft is partially or completely closed at one end and the specificity of the interaction is determined by placement of acidic residues in the cleft. Aromatic residues contribute to polyamine binding interacting with the carbon backbone. The polyamine-binding motif we have identified is very similar to that observed in the crystal structure of PotD, the primary receptor of the polyamine transport system in Escherichia coli.

Reference standards for determination of DNA content of plant nuclei

Flow cytometry was used to compare 14 potential reference standards for plant DNA content determination. Both chicken and plant internal standards were used, as were propidium iodide (PI) and 4'-6-diamidino-2-phenylindole (DAPI) as fluorochromes. Means and standard errors of the means are presented for the 14 potential reference standards, and the means are compared to those obtained by Feulgen densitometry. Five species are recommended as an initial set of international standards for future plant DNA content determinations: Sorghum bicolor cv. Pioneer 8695 (2C = 1.74 pg), Pisum sativum cv. Minerva Maple (2C = 9.56 pg), Hordeum vulgare cv. Sultan (2C = 11.12 pg), Vicia faba (2C = 26.66 pg), and Allium cepa cv. Ailsa Craig (2C = 33.55 pg). It is recommended that the reference standard of choice be one with 2C and 4C nuclear DNA content peaks similar to, but not overlapping, the 2C and 4C peaks of the target species. We recommend PI as the fluorochrome of choice for flow cytometric determination of plant DNA content. DAPI should be used only if the estimated DNA value is corroborated by using a second stain that has no bias for AT- or GC-rich sequences within genomes.

Port-access cardiac surgery protocols and early outcomes

As a new cardiac surgical procedure, port-access holds promise to significantly impact the surgical approaches for treatment of CAD. Supporting collaborative practice protocols contributes to early extubation, rapid in-hospital recovery, and shortened LOS. Discharge protocols address postoperative concerns. Early results suggest that patient recovery is shorter than the time for conventional procedures; patients are able to return to an active lifestyle that is beneficial to families, patients, and employers.

JSJ-1, an anti-spermidine monoclonal antibody with potential clinical applications

Polyamines have been implicated in a wide variety of functions including nucleic acid synthesis and protein synthesis. Their levels have been shown to increase in response to cell growth and differentiation. Use of polyamines as prognostic indicators of proliferative disease conditions has been hindered by the lack of suitable rapid and sensitive assays. We report the characterization of an anti-spermidine antibody, JSJ-1, with novel putrescine cross reactivity. JSJ-1 cross-reacts more strongly with putrescine (11%) than with spermine (6%). This suggests that the aminobutyl group common to both putrescine and spermidine is an important element in the antibody-antigen interaction. We have demonstrated that antibody-spermidine binding is effected by increased ionic strength. This finding is consistent with the antibody-antigen interaction being ionic. The JSJ-1 antibody has been successfully used to detect increased polyamine levels in clinical serum samples and identify those with increased polyamine levels.

Influence of light on DNA content of Helianthus annuus Linnaeus

Mean nuclear 2C DNA content (C equaling haploid DNA per nucleus) of the first leaf of the sunflower, Helianthus annuus L., is influenced by the quality and the quantity of light. Seedlings of two inbred lines, RHA 299 and RHA 271 were germinated and grown in controlled environmental conditions. Lighting was adjusted to provide different combinations of photon flux densities and red to far red (R:FR) ratios. At R:FR = 5.8 and photon flux densities of 170 mumol.m-2.s-1, 200 mumol.m-2.s-1, and 230 mumol.m-2.s-1, DNA content remained high and relatively constant (x = 6.97 pg for RHA 271 and x = 7.32 pg for RHA 299). When the photon flux density range (R:FR = 5.8) was elevated to 350 mumol.m-2.s-1, 410 mumol.m-2.s-1, and 470 mumol.m-2.s-1, mean DNA content was reduced to 6.23 pg (RHA 271) and 6.46 pg (RHA 299). At R:FR = 1.5, mean DNA content was consistently high (7.2-7.9 pg) only at the lowest photon flux density of 170 mumol.m-2.s-1. Significant decreases in DNA content (< or = 12%) were observed at photon flux densities of 200 mumol.m-2.s-1 and 230 mumol.m-2.s-1. At the higher photon flux densities (350 mumol.m-2.s-1, 410 mumol.m-2.s-1, and 470 mumol.m-2.s-1) and R:RF = 1.5, the plants had extremely low DNA contents (mean x = 3.36 pg for RHA 271 and 3.41 pg for RHA 299) and high between-plant variance. The instability of DNA content, particularly for plants grown under light that is far red rich, suggests that phytochromes may be involved in regulating DNA content of the sunflower.

DNA content of heterochromatin and euchromatin in tomato (Lycopersicon esculentum) pachytene chromosomes

Lycopersicon esculentum (tomato) has a small genome (2C = 1.90 pg of DNA) packaged in 2n = 2x = 24 small acrocentric to metacentric chromosomes. Like the chromosomes of other members of the family Solanaceae, tomato chromosomes have pericentromeric heterochromatin. To determine the fraction of the tomato genome found in euchromatin versus heterochromatin, we stained pachytene chromosomes from primary microsporocytes with Feulgen and analyzed them by densitometry and image analysis. In association with previously published synaptonemal complex karyotype data for tomato, our results indicate that 77% of the tomato microsporocyte genome is located in heterochromatin and 23% is found in euchromatin. If heterochromatin is assumed to contain few active genes, then the functional genes of the tomato must be concentrated in an effective genome of only 0.22 pg of DNA (1C = 0.95 pg x 0.23 = 0.22 pg). The physical segregation of euchromatin and heterochromatin in tomato chromosomes coupled with the small effective genome size suggests that tomato may be a more useful subject for chromosome walking and gene mapping studies than would be predicted based on its genome size alone. Key words : tomato, Lycopersicon esculentum, genome size, heterochromatin, euchromatin, pachytene chromosomes, synaptonemal complex.

The molecular through ecological genetics of abnormal abdomen in Drosophila mercatorum. V. Female phenotypic expression on natural genetic backgrounds and in natural environments

The abnormal abdomen (aa) syndrome in Drosophila mercatorum depends on the presence of R1 inserts in a third or more of the X-linked 28S rDNA genes and the absence of selective underreplication of inserted repeats in polytene tissues that is controlled by an X-linked locus (ur) half a map unit from the rDNA complex. This syndrome affects both life history and morphology in the laboratory. Because abnormal morphologies are rarely encountered in nature, the purpose of this study is to see if the female life history traits are still affected under more natural genetic backgrounds and environmental conditions. Two outbred stocks were extracted from the natural population living near Kamuela, Hawaii: KaaX that has only X chromosomes with uraa alleles, and K+X that has only ur+ alleles. These two stocks have nonoverlapping distributions of insert proportions, indicating strong disequilibrium between the ur locus and the rDNA complex. The KaaX stock had almost no morphological penetrance of uraa, indicating that genetic background is important. KaaX expressed longer female egg-to-adult developmental times, increased early adult female fecundity, and decreased female adult longevity compared with K+X. By bagging natural rots of the cactus Opuntia megacantha near Kamuela, Hawaii, it was shown that egg-to-adult developmental time is slowed down by 0.92 days in females bearing uraa alleles in nature, with no detectable slowdown in uraa males. The bagged rot data also indicate that females bearing uraa alleles have a strong fecundity advantage in nature under some ecological conditions but not others.

Aneuploidy, structural chromosome changes, and DNA amounts in the annual taxa of the Haplopappus spinulosus complex

Haplopappus gracilis (n = 2), Haplopappus ravenii (n = 4), and Haplopappus wigginsii (n = 4) are isolated by F1 hybrid sterility due mainly to translocation heterozygosity. There is no evidence that this can be overcome at the diploid level so that introgression can occur among them. They are also separated geographically, but occasional populations of H. gracilis and H. ravenii may be brought together along roadways to form sterile hybrids. There were no statistically significant differences in nuclear DNA content among the same or structurally different aneuploid n = 2 and n = 3 chromosome races or ecotypes of H. gracilis. Some of the H. gracilis races were not significantly different from one race of the ancestral H. ravenii, and these samples of both species were from plants growing on poor soils in contrast to accessions from normal habitats. How much and which classes of DNA in these species are subject to changes induced by environmental effects is not known. There were no correlations between DNA amounts and altitude, latitude, and longitude. H. wigginsii had a greater amount of DNA per nucleus than either H. ravenii or H. gracilis, and its increased DNA content may reflect a more rapid accumulation of noncoding sequences due to facultative self-compatibility not found in the other two species.

The molecular through ecological genetics of abnormal abdomen. IV. Components of genetic variation in a natural population of Drosophila mercatorum

Natural populations of Drosophila mercatorum are polymorphic for a phenotypic syndrome known as abnormal abdomen (aa). This syndrome is characterized by a slow-down in egg-to-adult developmental time, retention of juvenile abdominal cuticle in the adult, increased early female fecundity, and decreased adult longevity. Previous studies revealed that the expression of this syndrome in females is controlled by two closely linked X chromosomal elements: the occurrence of an R1 insert in a third or more of the X-linked 28S ribosomal genes (rDNA), and the failure of replicative selection favoring uninserted 28S genes in larval polytene tissues. The expression of this syndrome in males in a laboratory stock was associated with the deletion of the rDNA normally found on the Y chromosome. In this paper we quantify the levels of genetic variation for these three components in a natural population of Drosophila mercatorum found near Kamuela, Hawaii. Extensive variation is found in the natural population for both of the X-linked components. Moreover, there is a significant association between variation in the proportion of R1 inserted 28S genes with allelic variation at the underreplication (ur) locus such that both of the necessary components for aa expression in females tend to cosegregate in the natural population. Accordingly, these two closely linked X chromosomal elements are behaving as a supergene in the natural population. Because of this association, we do not believe the R1 insert to be actively transposing to an appreciable extent. The Y chromosomes extracted from nature are also polymorphic, with 16% of the Ys lacking the Y-specific rDNA marker. The absence of this marker is significantly associated with the expression of aa in males. Hence, all three of the major genetic determinants of the abnormal abdomen syndrome are polymorphic in this natural population.

Natural selection and ribosomal DNA in Drosophila

Natural populations of Drosophila mercatorum are variable for the number of X-linked 28S ribosomal genes bearing a 5-kilobase insert. A separate polymorphic X-linked gene controls whether 28S repeats bearing the insert are preferentially underreplicated during the formation of polytene tissue. Female flies having at least a third of their 28S genes bearing the insert and lacking the ability to preferentially underreplicate inserted repeats display the abnormal abdomen syndrome. The syndrome is characterized by retention of juvenile abdominal cuticle into the adult, a slowdown in larval developmental time, and an increase in early female fecundity. The life history traits are expressed in nature and provide a basis for strong natural selection. The abnormal abdomen syndrome should be favored whenever the adult age structure is skewed towards young individuals, and field studies confirm this prediction. The closely related species, Drosophila hydei, also bears these inserts and appears to be subject to similar selection. However, D. mercatorum responds to this selection primarily through the allelic variation that controls preferential underreplication, whereas D. hydei responds primarily through adjustment of the proportion of inserted 28S genes. This is interpreted to mean that the evolution of a multigene family arises from the interaction of population-level and DNA-level processes.

Temporal and spatial heterogeneity of mtDNA polymorphisms in natural populations of Drosophila mercatorum

Restriction endonuclease analysis of mtDNA was used to examine the genetic relatedness of several geographically separated isolines of the Drosophila mercatorum subgroup. In addition, we examined the temporal and spatial distribution of two mtDNA restriction site polymorphisms produced by the enzymes BstEII and BstNI at a single locality--Kamuela, Hawaii. Due to small sample sizes of some collections and the undesirable dependance of the estimation of polymorphism frequency on its variance, an arcsin square root transformation of the frequency data was used. We also use an Fst estimator of our transformed frequencies to demonstrate considerable spatial and temporal differentiation within the Kamuela population. In contrast, isozyme data from the same population reveals no pattern of differentiation. The temporal and geographic heterogeneity and population subdivision detected with mtDNA analysis also is consistent with the known dispersal behavior and ecological constraints of this species. The mtDNA data in conjunction with the isozyme data show that the population structure of the Kamuela D. mercatorum is close to the boundary line separating panmixia from subdivision, a conclusion that could not be made from isozyme data alone.

Thrombophlebitis migrans in association with ulcerative colitis

A case of thrombophlebitis migrans in a patient with ulcerative colitis is presented. The occurrence of thrombophlebitis was associated with an exacerbation of ulcerative colitis and responded well with the treatment of the underlying colitis. Evidence for a hypercoagulable state in ulcerative colitis is presented.

Delayed radiation necrosis of the brain

The cases of six patients are presented to delineate the clinical profile of delayed radiation necrosis of the brain. In five the diagnosis was verified histologically. Symptoms most often begin 9 months to 2 years after radiotherapy. Progressive visual impairment and dementia are common following perisellar irradiation, while hemispheric signs predominate following irradiation of the cerebrum. Cerebrospinal fluid protein may be elevated. Focal delta slowing is usually present on electroencephalography. The necrotic brain may appear on radionuclide brain scan as an area of abnormal uptake and also act as an avascular space-occupying lesion. With computerized tomography, radiation necrosis appears as an intracerebral area with diminished absorption coefficient that is often enhanced with intravenous contrast medium. The syndrome may be sufficiently characteristic to eliminate the need for surgical exploration and biopsy in some cases. Cumulative experience suggests that the risk-to-benefit ratio of radiotherapy becomes increasingly unfavorable for most patients with benign intracranial neoplasms when the standard brain tumor dose of 5000 to 7000 rads is fractionated at greater than 200 rads per day.

Ecological specialization of HawaiianDrosophila : Habitat selection in Kipuka Puaulu

TheDrosophila community of Kipuka Puaulu, Hawaii Volcanoes National Park, was studied by field measurements and laboratory experiments. Phototactic responses were related to oviposition substrates forD. mimica andD. imparisetae, and were shown to reinforce substrate attractiveness. Both species were associated with rottingSapindus fruit, butD. imparisetae, less light tolerant thanD. mimica, was found in deeper shade. Individuals of a third species,D. kambysellisi, were strongly attracted to substratePisonia leaves. The attraction was strong enough to override strong positive phototaxis. The significance of this behavior was related to the adaptive strategy of the species. The sibling species,D. mimica andD. kambysellisi, utilized different substrates and were strongly separated spatially. Differences in substrates and mobility were related to the "grain size" of their environment. Males ofD. kambysellisi andD. imparisetae are located in leking sites above their respective females during the day. This behavior parallels the relatively greater light tolerance of males than of females. The same light response dimorphism inD. mimica is not accompanied by leking behavior, since they mate at night or in greatly subdued light.

Behavioral components of dispersal in Drosophila mimica

In the Hawaiian species, Drosophila mimica, it was necessary to determine the dispersal pattern in order to interpret genetic heterogeneity observed in the population. In addition, the pattern of colonization and speciation in the Drosophila community may have been affected by the dispersal behavior and response to infrequent conditions of environmental factors which would encourage sporadic movement. It was not possible in this experiment to measure such behavior directly, but predictions are possible.Dispersal patterns are formulated in terms of component behavioral responses to particular environmental cues. Under appropriate field measurements, the relationship of behavior patterns of D. mimica to air movement, light, humidity, and food substrate were sufficient to interpret a complex dispersal pattern in the field. Predictions were made for other movement patterns over longer distances and with infrequent occurrence.Present results are explainable by the response of D. mimica to low velocity air currents. Flies move into the current at velocities less than about 3.3 km/hr, and this response is consistent with field observations of insect and air movements. Visible light intensities from more than 10 to about 100 lux were most acceptable to this species, and movement was restricted to light periods.Based upon responses of D. mimica to wind, light, humidity, and attractive areas, long range dispersal would likely occur between two habitats when each had suitable food substrates, the weather was very humid, overcast, and when there was a slight air current between the habitats. Movement would be unidirectional only if air current patterns were stable. The most precise navigation would be at air current velocities below 3.3 km/hr, where olfactory orientation on the substrate in the new habitat would be possible and short flights would be upwind. However, longer range movements would be possible downwind at slightly higher velocities.Genetic data on D. mimica has been interpreted to reflect differences in selection between at least moderately isolated habitats. Our results indicate that, instead of isolated populations, these habitats contain populations that are part of a single deme with sporadic mixing. Genetic heterogeneity may temporarily result from intense localized selection pressure between periods of mixing.Furthermore, the presence of several sibling species (some undescribed) in Kipuka Puaulu and in several neighboring areas clearly illustrates the fragmentation of gene pools and the genetic differentiation which is possible. Since D. mimica might move from one kipuka to another, spatial isolation is unlikely to play a major role in speciation, whereas habitat selection and ethological isolation may be the principal mechanisms of speciation.

Allozyme genotype-environment relationships. I. Variation in natural populations of Drosophila pachea

Remarkable geographic and seasonal uniformities in gene and genotype frequencies were found for four enzyme loci. Principal component analysis revealed two patterns of allele frequency changes in three of the allozyme loci (Est-b, Est-c and Acph) and one pattern in the Mdh-d locus. These patterns accounted for 90% to 100% of the variability at these loci. Significant positive correlations were obtained between several of the components and the variability in the non-saponifiable and alkaloid fractions of the senita cactus host plant. The genetic variance within a single locality (Guaymas, Mexico) was as great as the variance between all localities sampled. This is interpreted as a local founder effect. The temporary nature of the rotting cactus breeding site, the delayed maturation and the differential maturation rate of females and males are three factors proposed to cause forced outbreeding and counter the local founder effect. A combination of selection resulting from a direct interaction of the genotype and the environment, in addition to migration, is proposed to maintain the uniform gene frequencies.