In vitro and in vivo effects of gliotoxin, a fungal metabolite: efficacy against dextran sodium sulfate-induced colitis in rats

Gliotoxin is a fungal metabolite that has immunosuppressive properties. First, we determined if gliotoxin could inhibit cytokine production from macrophage and colonic epithelial cell lines, as well as whether it inhibited nuclear factor-kappa B in these same cell types. Second, we evaluated whether gliotoxin could reduce dextran sodium sulfate-induced colitis in rats. A disease activity index, myeloperoxidase activity, and cytokine levels were evaluated on either day 7 or 21. In both cell lines, gliotoxin dose dependently inhibited cytokine production and nuclear factor-kappa B. On day 21, gliotoxin significantly reduced disease activity (diarrhea and bloody stools) in rats. On day 7, gliotoxin treatment significantly improved various indices of colitis, including colonic cytokine levels. Decreased food consumption and weight gain was evident with a larger dose of gliotoxin. In summary, gliotoxin, a nuclear factor-kappa B inhibitor, effectively reduced dextran sodium sulfate-induced colitis in rats. However, gliotoxin exhibited a narrow therapeutic to toxicity ratio in these rats.

Actions of Ginkgo Biloba related to potential utility for the treatment of conditions involving cerebral hypoxia

Neuronal hypoxia results from a variety of cerebrovascular accidents or 'normal' age-associated anatomic changes. The consequences vary from mild deficits in neurologic function to massive neuropathology. Present pharmacotherapeutic therapy is not ideal. Two apparently disparate approaches to the search for better treatment or prevention-one involving reassessment of herbal remedies as 'alternative' medicine and the other one involving the desirability of increased structural diversity in HTS (high-throughput screening) libraries and as combinatorial chemistry templates-have converged in a rekindling of interest and a reevaluation of the pharmacologic properties of substances such as extract from the leaves of Ginkgo biloba Linne (form. Salisburia adiantifolia Sm.). There are reports of positive results from a small number of controlled clinical trials (albeit with small numbers of patients) sufficient to suggest that 'Ginkgo' might have therapeutic benefit in some situations or subset of patients. The pharmacologic mechanism by which Ginkgo might be able to provide the observed effect is not clear. However, it is believed that the flavonoid and terpenoid components of Ginkgo extract might produce beneficial therapeutic effects through mechanisms acting separately or in concert, such as the antagonism of PAF (platelet activating factor), antioxidant and metabolic actions, and effects on neurotransmitters. These mechanisms are reviewed in this article.

Differential leptin responses to acute and chronic biliary obstruction in rats

BACKGROUND/AIMS

Recently leptin, a protein released from adipocytes, has been identified as a potent circulating satiety factor. We therefore undertook this series of experiments to examine leptin's role in the anorexia associated with biliary obstruction.

METHODS

Rats underwent either surgical bile duct resection (BDR) or sham resection (sham). Body weight, and food and water intake were measured during a baseline period and for 8 days after surgery. At 4, 8 and 16 h as well as on days 2, 4, 6, and 8 postsurgery, sham and BDR rats were sacrificed and sera collected for subsequent measurement of leptin hormone concentration by RIA. White adipose tissue was collected on days 2, 4, 6 and 8 for leptin mRNA determination by Northern blot.

RESULTS

Obstructive cholestasis in BDR rats caused significant anorexia for up to 7 days post-surgery, whereas in sham rats, a significant decrease in food intake was only observed in the first 24-h period following surgery. In both sham and BDR rats, water intake was significantly decreased during the first 24-h period after surgery, but had recovered to baseline levels by day 2 in both groups. Fat pad mass corrected to body weight was not significantly different between the two experimental groups. Serum leptin levels were significantly increased 4 and 8 h after surgery, had normalized by 16 h post-surgery, and were then decreased in BDR rats on days 2, 4, 6 and 8 compared with controls. Leptin mRNA levels in epididymal fat pads were decreased by approximately 2-fold in BDR rats compared with sham rats on days 2, 4, 6 and 8. Furthermore, day 5 BDR and sham rats demonstrated similar anorectic responses to centrally administered leptin.

CONCLUSIONS

Leptin production is significantly increased early after biliary obstruction but is reduced after prolonged biliary obstruction. Increased circulating leptin levels may contribute to the profound anorexia observed early after biliary obstruction but appear not to mediate the anorexia observed during more chronic biliary obstruction.

Attenuated febrile response to lipopolysaccharide in rats with biliary obstruction

Patients with biliary tract obstruction have unexplained, inordinately high rates of perioperative morbidity and mortality, whereas cholestatic animals display abnormal hypothalamic responses to pyrogenic stimuli. We asked if obstructive cholestasis was associated with abnormal fever generation. Male Sprague-Dawley rats (250 g) underwent laparotomy for implantation of thermistors and either bile duct resection (BDR) or sham operation. After recovery, temperatures were recorded by telemetry and conscious, unrestrained rats in each group were injected intraperitoneally with either interleukin-1beta (IL-1beta;1 microg/kg) or Escherichia coli lipopolysaccharide (LPS; 50 microg/kg). Baseline temperatures in both groups were similar. Febrile responses after IL-1beta injection in BDR and sham groups were not significantly different. However, in response to LPS injection, BDR rats showed an initial hypothermia with a subsequently attenuated febrile response. Administration of anti-tumor necrosis factor-alpha (TNF-alpha) antibody 2 h before LPS injection blocked the LPS-induced hypothermia seen in BDR animals. However, serum levels of TNF-alpha were not significantly different between sham and BDR animals after LPS injection at any time point measured (0, 1.5, and 3 h).

Follicular lymphomas' BCL-2/IgH junctions contain templated nucleotide insertions: novel insights into the mechanism of t(14;18) translocation

The human t(14;18) chromosomal translocation is assumed to result from illegitimate rearrangement between BCL-2 and D(H)/J(H) gene segments during V(D)J recombination in early B cells. De novo nucleotides are found inserted in most breakpoints and have been thus far interpreted as nontemplated N region additions. In this report, we have analyzed both direct (BCL-2/J(H)) and reciprocal (D(H)/BCL-2) breakpoints derived from 40 patients with follicular lymphoma with t(14;18). Surprisingly, we found that more than 30% of the breakpoint junctions contain a novel type of templated nucleotide insertions, consisting of short copies of the surrounding BCL-2, D(H), and J(H) sequences. The features of these templated nucleotides, including multiplicity of copies for 1 template and the occurrence of mismatches in the copies, suggest the presence of a short-patch DNA synthesis, templated and error-prone. In addition, our analysis clearly shows that t(14;18) occurs during a very restricted window of B-cell differentiation and involves 2 distinct mechanisms: V(D)J recombination, mediating the breaks on chromosome 14 during an attempted secondary D(H) to J(H) rearrangement, and an additional unidentified mechanism creating the initial breaks on chromosome 18. Altogether, these data suggest that the t(14;18) translocation is a more complex process than previously thought, involving the interaction and/or subversion of V(D)J recombination with multiple enzymatic machineries.

Minimal catalytic domain of N-acetylglucosaminyltransferase V

UDP-GlcNAc: Manalpha1-6Manbeta-R beta1-6 N-acetylglucosaminyltransferase V (EC 2.4.1.155, GlcNAc-TV) is a Golgi enzyme that substitutes the trimannosyl core in the biosynthetic pathway for complex-type N-linked glycans. GlcNAc-TV activity is regulated by oncogenes frequently activated in cancer cells ( ras, src, and her2/neu ) and by activators of T lymphocytes. Overexpression of GlcNAc-TV in epithelial cells results in morphological transformation, while tumor cell mutants selected for loss of GlcNAc-TV products show diminished malignant potential in mice. In this report, we have expressed and characterized a series of N- and C-terminal deletions of GlcNAc-TV. Portions of GlcNAc-TV sequence were fused at the N-terminal domain to IgG-binding domains of staphylococcal Protein A and expressed in CHOP cells. The secreted fusion proteins were purified by IgG Sepharose affinity chromatography and assayed for enzyme activities. The peptide sequence S(213-740)of GlcNAc-TV was determined to be essential for the catalytic activity, the remaining amino acids comprising a 183 amino acid stem region, a 17 amino acid transmembrane domain and a 12 amino acid cytosolic moiety. Further deletion of 5 amino acids to produce peptide R(218-740)reduced enzyme activity by 20-fold. Similar K(m)and V(max)values for donor and acceptor were observed for peptide S(213-740), the minimal catalytic domain, and peptide Q(39-740), which also included the stem region. Truncation of five amino acids from the C-terminus also resulted in a 20-fold loss of catalytic activity. Secondary structure predictions suggest a high frequency of turns in the stem region, and more contiguous stretches of alpha-helix found in the catalytic domain.

Routine HLA-B genotyping with PCR-sequence-specific oligonucleotides (PCR-SSO) detects eight new alleles: B*0807, B*0809, B*1551, B*3529, B*3532, B*4025, B*5304 and B*5508

This paper describes eight new alleles (B*0807, B*0809, B*1551, B*3529, B*3532, B*4025, B*5304 and B*5508) that have been found by routine HLA-B genotyping with sequence-specific oligonucleotides (SSOs). All of the new alleles have variations which cause changes in residues that occur within antigen binding pockets and T-cell recognition sites of the antigen. The new polymorphisms within these new alleles may affect the nature and specificity of peptide binding and cause differential T-cell activation, which may have an affect in transplantation.

HLA and other host factors in transfusion-acquired HIV-1 infection

The host and viral factors that underlie infection with HIV-1 vary considerably with some individuals progressing to AIDS within 3 to 5 years after infection, whereas others remain clinically asymptomatic for over 10 years. Host factors that may contribute to disease progression include HLA and allelic variants of the chemokine receptors CCR5 and CCR2, which have been shown to influence both long-term survival and rapid progression. In this study, we have examined the contribution of HLA and polymorphisms in CCR5 and CCR2 to long-term survival in transfusion-acquired HIV-1-infected individuals. We have found a higher number of HLA-A32 and -A25 alleles but a lower number of the HLA-B8 allele in the study group compared with the frequencies seen in the HIV-1-negative Australian caucasian population. However, there was no apparent contribution by allelic variants of CCR5 and CCR2 to long-term survival and the combined influence of HLA and CCR polymorphisms could not be evaluated in this relatively small (n = 20) group of study subjects. The results of this work support a role for HLA in long-term nonprogression though the presence in the Sydney Blood bank Cohort of nef-defective HIV-1 may confound associations between certain HLA alleles and long-term survival in the face of infection with HIV-1.

Tumor necrosis factor-related apoptosis-inducing ligand's antitumor activity in vivo is enhanced by the chemotherapeutic agent CPT-11

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can induce apoptosis in a wide variety of transformed human cells in vitro. In this study, the antitumor activity of recombinant TRAIL was analyzed in mice bearing human colon carcinoma tumors. We found that these tumors displayed a differential sensitivity to TRAIL in vivo that paralleled their susceptibility to TRAIL-induced apoptosis in vitro. Treatment of TRAIL-sensitive tumors 3 days after tumor challenge resulted in a dose-dependent inhibition of growth and the elimination of tumors in many mice. Colon carcinoma cell lines could be further sensitized to TRAIL-induced apoptosis in vitro by the addition of the chemotherapeutic agent camptothecin. Moreover, the combination of TRAIL and CPT-11, a water-soluble analogue of camptothecin, greatly enhanced the antitumor activity of TRAIL in vivo. TRAIL plus CPT-11 treatment of both 3- and 10-day established TRAIL-sensitive tumors resulted in both a significant inhibition of tumor growth and a high proportion of complete tumor regressions. Treatment of TRAIL-resistant tumors with TRAIL and CPT-11 dramatically slowed tumor growth and induced a transient tumor regression. These data demonstrate that TRAIL alone is a potent antitumor agent in vivo, and its activity can be significantly enhanced in combination with the chemotherapeutic agent CPT-11.

Effect of naproxen on the hamster gastric antrum: ulceration, adaptation and efficacy of anti-ulcer drugs

BACKGROUND

Various animal models of non-steroidal anti-inflammatory drug (NSAID)-induced gastric ulceration exist. These models have limitations, which make them less relevant to the human situation.

AIM

: To develop a more simple and more relevant model of NSAID-induced gastric ulceration and adaptation.

METHODS

Gastric ulceration was evaluated following the orogastric administration of naproxen (80 mg/kg b.d.) to hamsters. The effects of misoprostol and famotidine on gastric acid secretion and ulceration were also determined. Gastric adaptation was evaluated by proliferating cell nuclear antigen (PCNA) immunohistochemistry, in hamsters given naproxen for 3 weeks. Antral resistance to acute injury by NSAIDs and ethanol was also determined in these animals.

RESULTS

Naproxen caused primarily gastric antral ulceration, which decreased from day 3 to day 21. This gastric adaptation was accompanied by an increase in PCNA positive cells, particularly on days 7 and 14. The adapted gastric antral mucosa was resistant to acute damage by various agents. Misoprostol (1 or 100 microg/kg) prevented antral ulceration, without affecting gastric acid secretion. Despite decreasing acid output by> 90%, famotidine (30 mg/kg) failed to prevent ulceration.

CONCLUSION

The administration of naproxen (80 mg/kg b.d.) to hamsters is a simple, reliable and relevant method for evaluating NSAID-induced gastric antral ulceration and adaptation.

Clinically apparent early stage invasive epithelial ovarian carcinoma: should all be treated similarly?

OBJECTIVES

The role of adjuvant therapy in patients with early stage ovarian carcinoma has not been clearly defined. Most randomized trials examining this issue have not used the vigorous staging exploration accepted as today's standard. This report examines the natural history of patients after surgically documented stage 1 ovarian carcinoma followed expectantly.

METHODS

A retrospective chart review was carried out using strict criteria to include only patients who had an adequate staging procedure performed by gynecologic oncologists following a fixed protocol from 1987 to 1997. Patients' demographic data as well as current disease status were abstracted and analyzed.

RESULTS

A total of 80 comprehensive surgical staging procedures were carried out over a 10-year period for apparent stage 1 ovarian cancer at the time of exploratory laparotomy. Fifty cases were true surgicopathological stage 1. It was found that serous and anaplastic tumors were more likely than other subtypes to be upstaged by the procedure. Further follow-up confirmed the excellent prognosis of early stage serous, endometrioid, and mucinous tumor with only one recurrence noted in an extraabdominal location in a patient with serous histology with no postoperative adjuvant therapy. Clear cell histology stands out as a significant recurrence risk (33%) despite an initially negative surgical assessment.

CONCLUSION

Careful surgical exploration can identify a group of patients with early stage epithelial ovarian carcinoma who will benefit little from further adjuvant therapy. Patients with clear cell histology prove to be at a high risk for recurrence even at an early stage such that chemotherapy should be considered.

Identification of survival motor neuron as a transcriptional activator-binding protein

Spinal muscular atrophy (SMA) is an inherited neuro-muscular disease characterized by specific degeneration of spinal cord anterior horn cells and subsequent muscle atrophy. Survival motor neuron ( SMN ), located on chromosome 5q13, is the SMA-determining gene. In the nucleus, SMN is present in large foci called gems, the function of which is not yet known, while cytoplasmic SMN has been implicated in snRNP biogenesis. In SMA patients, SMN protein levels and the number of gems generally correlate with disease severity, suggesting a critical nuclear function for SMN. In a screen for proteins associated with the nuclear transcription activator 'E2' of papillomavirus, two independent SMN cDNAs were isolated. The E2 and SMN proteins were found to associate specifically in vitro and in vivo. Expression of SMN enhanced E2-dependent transcriptional activation, and patient-derived SMN missense mutations reduced E2 gene expression. Our results demonstrate that SMN interacts with a nuclear transcription factor and imply that SMN may serve a role in regulating gene expression. These observations suggest that SMA may in part result from abnormal gene expression and that E2 may influence viral gene expression through SMN interaction.

The spectrum of mutations in TBX3: Genotype/Phenotype relationship in ulnar-mammary syndrome

Ulnar-mammary syndrome (UMS) is a pleiotropic disorder affecting limb, apocrine-gland, tooth, hair, and genital development. Mutations that disrupt the DNA-binding domain of the T-box gene, TBX3, have been demonstrated to cause UMS. However, the 3' terminus of the open reading frame (ORF) of TBX3 was not identified, and mutations were detected in only two families with UMS. Furthermore, no substantial homology outside the T-box was found among TBX3 and its orthologues. The subsequent cloning of new TBX3 cDNAs allowed us to complete the characterization of TBX3 and to identify alternatively transcribed TBX3 transcripts, including one that interrupts the T-box. The complete ORF of TBX3 is predicted to encode a 723-residue protein, of which 255 amino acids are encoded by newly identified exons. Comparison of other T-box genes to TBX3 indicates regions of substantial homology outside the DNA-binding domain. Novel mutations have been found in all of eight newly reported families with UMS, including five mutations downstream of the region encoding the T-box. This suggests that a domain(s) outside the T-box is highly conserved and important for the function of TBX3. We found no obvious phenotypic differences between those who have missense mutations and those who have deletions or frameshifts.

Efficacy of three-phase bone scans in evaluating diabetic foot ulcers

To evaluate the utility of bone scans in determining the treatment of diabetic patients with foot ulcers, a retrospective study was conducted. Medical records were reviewed for clinical signs of infection, laboratory data, and the radiologists' interpretations of imaging studies. During the study period, 34 bone scans were obtained by the treating physicians to evaluate diabetic foot ulcers. Among these, 22 of 34 bone scans were markedly confirmatory of being "consistent with osteomyelitis," 8 of 34 were moderately confirmatory ("indeterminate with regard to osteomyelitis"), and 4 of 34 were not confirmatory ("not consistent with osteomyelitis"). Of the 22 patients in the markedly confirmatory group, eight patients with clinical findings of uncontrolled infection or gangrene were treated with partial or complete amputation, whereas all others (14 patients) were treated with local wound care+/-intravenous antibiotics. Among the eight bone scans interpreted as indeterminate, three patients required partial or complete amputation, whereas the other five patients were managed with local wound care. Of the four patients with nonconfirmatory bone scans, two patients had evidence of dry gangrene and required amputation, whereas the other two patients did not have clinical evidence of infection or gangrene and were treated with local wound care. There was no significant difference in the amputation rate for patients with confirmatory, indeterminate, or nonconfirmatory bone scans for osteomyelitis (36%, 37%, and 50%, respectively) (P > 0.5). Therefore, the authors concluded that the ultimate treatment should be based on clinical indicators of the presence of uncontrolled infection or gangrene rather than on bone scan findings.

Peptide based cytotoxic T-cell vaccines; delivery of multiple epitopes, help, memory and problems

Synthetic CD8+ cytotoxic T-lymphocyte (CTL) peptide epitope based vaccines are being developed against a number of human diseases. Here we describe extensive preclinical testing of peptide epitope vaccines formulated with a protein as a source of CD4 help and Montanide ISA 720, an adjuvant currently in human clinical trials. Such water-in-oil formulations could effectively co-deliver several peptide epitopes and simultaneously induce multiple independent CTL responses. The efficiency of CTL induction by some peptides was, however, dependent on the aqueous buffer conditions, with poor performance correlating with non-covalent peptide oligomerisation. Any of a number of proteins currently used in human vaccines could supply CD4 help and no difference in CTL induction was obtained if the CD4 response was amnestic or a primary. Peptide immunisation was found to induce long term CTL memory and the recall of protective responses did not depend on an amnestic CD4 response. Slow pyroglutamic acid formation and rapid oxidation of methionine residues was observed in water-in-oil formulations, however, the latter had no effect on CTL induction. These data highlight the need to monitor for potential deleterious chemical events and interpeptide interactions, but illustrate that peptide based vaccination can effectively deliver multiple epitopes, in conjunction with any protein, and induce protective memory.

Flexible programs for the prediction of average amphipathicity of multiply aligned homologous proteins: application to integral membrane transport proteins

Simple flexible programs (TREEMOMENT and PILEUPMOMENT) are described for depicting the average amphipathicity (hydrophobic moment) along multiply aligned sequences of a family of evolutionarily related proteins. The programs are applicable to any number of aligned sequences and can be set for any desired angle corresponding to a residue repeat unit in a protein secondary structural element such as 100 degrees per residue for an alpha-helix or 180 degrees per residue for a beta-strand. These programs can be used to identify amphipathic regions common to the members of a protein family. The use of these programs is exemplified by showing that some families of integral membrane transport proteins (i.e. permeases of the bacterial phosphotransferase system (PTS) and the anion exchangers of animals) exhibit strikingly amphipathic alpha-helical structures immediately preceding the first hydrophobic transmembrane segment of their membrane-embedded domain(s). Other families, such as the major facilitator superfamily of uniporters, symporters and antiporters, do not exhibit this structural feature. The amphipathic structures in PTS permeases have been implicated in membrane insertion during biogenesis.

Plasmid DNA malaria vaccine: the potential for genomic integration after intramuscular injection

Plasmid-based (naked DNA) genetic vaccines are now entering clinical trials to test their safety and efficacy in healthy human volunteers. A safety concern unique to this new class of vaccines is the potential risk of deleterious integration into host cell genomic DNA following direct intramuscular injection. To address this issue experimentally, a preclinical safety study was conducted in mice to determine the structural nature of plasmid DNA sequences persisting in total muscle DNA at both 30 and 60 days following a single intramuscular injection of a plasmid expressing the Plasmodium falciparum circumsporozoite protein. In a protocol described for the first time, total DNA was extracted from muscle tissue and was subsequently linearized with a restriction endonuclease to enable agarose gel size fractionation of all extrachromosomal plasmid DNAs from high molecular weight mouse genomic DNA. Using PCR assays to quantitate plasmid-specific sequences, it was found that the amount of plasmid DNA persisting in muscle tissue varied but averaged about 10 fg per microgram of genomic DNA (in the range of 1500 copies per 150,000 genomes). In two of four separate experimental injections of mouse muscle, PCR assays of genomic DNA fractions indicated that agarose gel purification removed plasmid DNA down to a level of < or =3 copies per 150,000 mouse genomes. In the two other experimental samples, 3-30 copies of plasmid DNA remained associated with purified genomic DNA. The time following injection (i.e., 30 or 60 days) was not a factor in the number of copies of plasmid associating with genomic DNA and it was not possible to conclude if such sequences were covalently linked to genomic DNA or simply adventitiously associated with the genomic DNA. However, if an assumption is made that the highest level plasmid DNA found associated with genomic DNA (i.e., 30 copies) represented covalently integrated plasmid inserts and that each insert resulted in a mutational event, the calculated rate of mutation would be 3000 times less than the spontaneous mutation rate for mammalian genomes. This level of integration, if it should occur, was not considered to pose a significant safety concern.

Plasmid DNA malaria vaccine: tissue distribution and safety studies in mice and rabbits

To evaluate the safety of a plasmid DNA vaccine, tissue distribution studies in mice and safety studies in mice and rabbits were conducted with VCL-2510, a plasmid DNA encoding the gene for the malaria circumsporozoite protein from Plasmodium falciparum (PfCSP). After intramuscular administration, VCL-2510 plasmid DNA was detected initially in all of the highly vascularized tissues, but at later time points was found primarily in the muscle at the site of injection, where it persisted for up to 8 weeks. After intravenous administration, plasmid DNA initially distributed at a relatively low frequency to all the tissues examined except the gonads and brain. However, plasmid DNA rapidly cleared, and by 4 weeks postadministration could be detected only in the lung of one of six animals evaluated. In a safety study in mice, eight repeated intramuscular injections of VCL-2510 at plasmid DNA doses of 1, 10, and 100 microg had no adverse effects on clinical chemistry or hematology, and did not result in any organ pathology or systemic toxicity. In a safety study in rabbits, six repeated intramuscular injections of VCL-2510 at plasmid DNA doses of 0.15 and 0.45 mg had no discernible effects on clinical chemistry, hematology, or histopathology. No evidence of autoimmune-mediated pathology, anti-nuclear antibodies (ANA), or antibodies to dsDNA were observed in the mouse or rabbit studies.

Reconstructing the history of human limb development: lessons from birth defects

A major goal of biology has been to understand the developmental mechanisms behind evolutionary trends. This has led to a growing interest in studying the molecular basis of the evolution of developmental programs such as those mediating the diversification of tetrapod limbs. Over the last 10 y, it has become clear that the genes and general developmental programs used to build a limb are strongly conserved among widely disparate species. This finding suggests that altered regulation of the timing and locations of developmental events may be responsible for the morphologic variation observed among some species. However, genetic analyses of the regulatory regions of genes controlling vertebrate developmental programs are very limited. Characterization of the genetic basis of human birth defects of the limb provides an opportunity to dissect the developmental programs used to modify the architecture of the hominoid limb. This may allow us to assess the relative contributions of altered gene regulation to morphologic variation among species and reconstruct the evolutionary history of the hominid limb. Such insight is also important because morphologic differences in the hominid upper limb have been correlated with the use of tools, and tool making is often regarded as the milestone that marked the emergence of the genus Homo.

Indomethacin-induced gastric antral damage in hamsters: are neutrophils involved?

BACKGROUND

A direct role for neutrophils in the pathophysiology of indomethacin-induced gastric damage is controversial. Therefore, such damage was evaluated in hamsters.

METHODS

Gastric antral damage was evaluated 4 h after the oro-gastric administration of indomethacin (30 mg/kg). Prior to indomethacin, hamsters were treated with various pharmacological agents: rebamipide, methotrexate or anti-neutrophil serum (ANS). The number of circulating neutrophils was determined from Wright-Giemsa stained blood smears. Myeloperoxidase (MPO) activity was measured as a marker of gastric antral neutrophil infiltration.

RESULTS

Indomethacin caused primarily gastric antral damage. By histology, this damage did not penetrate the muscularis mucosa. A significant increase in gastric antral MPO activity was also found in indomethacin-treated hamsters. Rebamipide decreased macroscopic gastric antral damage in a dose-related fashion. Methotrexate treatment reduced the circulating blood neutrophil number by 38-44%, but did not affect gastric damage. ANS treatment resulted in near complete neutropenia, and also in a substantial reduction (84%) in gastric antral MPO activity. However, gastric antral damage was not significantly altered by ANS.

CONCLUSIONS

Neutrophils are not directly involved in the pathophysiology of indomethacin-induced damage to the hamster gastric antrum.

Tumoricidal activity of tumor necrosis factor-related apoptosis-inducing ligand in vivo

To evaluate the utility of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as a cancer therapeutic, we created leucine zipper (LZ) forms of human (hu) and murine (mu) TRAIL to promote and stabilize the formation of trimers. Both were biologically active, inducing apoptosis of both human and murine target cells in vitro with similar specific activities. In contrast to the fulminant hepatotoxicity of LZ-huCD95L in vivo, administration of either LZ-huTRAIL or LZ-muTRAIL did not seem toxic to normal tissues of mice. Finally, repeated treatments with LZ-huTRAIL actively suppressed growth of the TRAIL-sensitive human mammary adenocarcinoma cell line MDA-231 in CB.17 (SCID) mice, and histologic examination of tumors from SCID mice treated with LZ-huTRAIL demonstrated clear areas of apoptotic necrosis within 9-12 hours of injection.

Frequent deregulation of p16 and the p16/G1 cell cycle-regulatory pathway in neuroblastoma

Alterations of the p16 gene in neuroblastoma are very rare. Pronounced expression of p16 at both the transcript and protein levels, however, was observed in 7 of 19 (39%) neuroblastoma cell lines and 2 of 6 (33%) primary neuroblastoma samples. As p16 expression is tightly controlled in a feedback loop with Rb, we investigated the possibility that changes in p16 expression were reflective of alterations of the downstream components in the G1 regulatory pathway. Two cell lines and one primary sample highly expressing p16 were shown to harbor CDK4 amplification. The cyclin D2 gene was infrequently expressed in neuroblastoma cell lines and did not correlate with p16 expression. Slight variations in the expression of CDK6, cyclins D1, D3 and E; and E2F1 and E2F2 among the cell lines were observed, without apparent correlation with p16 status. No mutations to the p16-binding site of CDK4 and CDK6 nor any mutations to the coding region of p16 itself were identified in neuroblastoma cell lines. Despite frequent N-myc amplification in these cell lines, no relationship with this gene was observed either. All cell lines contained Rb protein with varying degrees of phosphorylation, which bears no correlation with p16 expression. Overall, alterations of the G1 pathway in neuroblastoma included relatively frequent p16 expression and infrequent CDK4 amplification and cyclin D2 expression. Despite a reported feedback relationship between p16 expression and Rb/G1 deregulation, p16 expression in neuroblastoma cell lines is independent of Rb gene and phosphorylation status and, in contrast to other cell lines where expression of p16 leads to G1/S arrest, neuroblastoma cell lines proliferate in the presence of elevated levels of p16.

Endogenous glucocorticoids released during acute toxic liver injury enhance hepatic IL-10 synthesis and release

Endogenous glucocorticoids are known to play a role in the regulation of the inflammatory response possibly by modulating pro- and anti-inflammatory cytokine expression. We examined endogenous glucocorticoid secretion, hepatic damage, tumor necrosis factor-alpha (TNF-alpha), and interleukin-10 (IL-10) mRNA expression and release in rats treated with carbon tetrachloride (CCl4) after treatment with vehicle or a glucocorticoid receptor antagonist (RU-486). Rats treated with CCl4 demonstrated striking elevations of plasma corticosterone levels. Inhibition of endogenous glucocorticoid activity by pretreatment with the glucocorticoid receptor antagonist RU-486 resulted in augmented CCl4-mediated hepatotoxicity, as reflected by histology and serum transaminase levels, which were independent of alterations in serum TNF-alpha levels or hepatic mRNA expression. CCl4 treatment resulted in enhanced hepatic IL-10 mRNA expression and elevated serum IL-10 levels, which were markedly attenuated by glucocorticoid receptor blockade. In summary, significant endogenous glucocorticoid release occurs during acute toxic liver injury in the rat and suppresses the inflammatory response independent of effects on TNF-alpha but possibly by upregulating hepatic IL-10 production.

Lipid A mutant Salmonella with suppressed virulence and TNFalpha induction retain tumor-targeting in vivo

Systemically administered tumor-targeted Salmonella has been developed as an anticancer agent, although its use could be limited by the potential induction of tumor necrosis factor alpha (TNFalpha)-mediated septic shock stimulated by lipid A. Genetic modifications of tumor-targeting Salmonella that alter lipid A and increase safety must, however, retain the useful properties of this bacteria. We report here that disruption of the Salmonella msbB gene reduces TNFalpha induction and increases the LD50 of this pathogenic bacteria by 10,000-fold. Notwithstanding this enormous difference, Salmonella retains its tumor-targeting properties, exhibiting tumor accumulation ratios in excess of 1000:1 compared with normal tissues. Administration of this bacteria to mice bearing melanoma results in tumors that are less than 6% the size of tumors in untreated controls at day 18. Thus, the antitumor activity previously demonstrated using tumor-targeting Salmonella with normal lipid A is retained. Lipid modification of tumor-specific bacterial vectors provides a means for reducing septic shock and further suggests that the antitumor activity of these bacteria may be independent of TNFalpha.

Reduced growth, abnormal kidney structure, and type 2 (AT2) angiotensin receptor-mediated blood pressure regulation in mice lacking both AT1A and AT1B receptors for angiotensin II

The classically recognized functions of the renin-angiotensin system are mediated by type 1 (AT1) angiotensin receptors. Whereas man possesses a single AT1 receptor, there are two AT1 receptor isoforms in rodents (AT1A and AT1B) that are products of separate genes (Agtr1a and Agtr1b). We have generated mice lacking AT1B (Agtr1b -/-) and both AT1A and AT1B receptors (Agtr1a -/-Agtr1b -/-). Agtr1b -/- mice are healthy, without an abnormal phenotype. In contrast, Agtr1a -/-Agtr1b -/- mice have diminished growth, vascular thickening within the kidney, and atrophy of the inner renal medulla. This phenotype is virtually identical to that seen in angiotensinogen-deficient (Agt-/-) and angiotensin-converting enzyme-deficient (Ace -/-) mice that are unable to synthesize angiotensin II. Agtr1a -/-Agtr1b -/- mice have no systemic pressor response to infusions of angiotensin II, but they respond normally to another vasoconstrictor, epinephrine. Blood pressure is reduced substantially in the Agtr1a -/- Agtr1b -/- mice and following administration of an angiotensin converting enzyme inhibitor, their blood pressure increases paradoxically. We suggest that this is a result of interruption of AT2-receptor signaling. In summary, our studies suggest that both AT1 receptors promote somatic growth and maintenance of normal kidney structure. The absence of either of the AT1 receptor isoforms alone can be compensated in varying degrees by the other isoform. These studies reaffirm and extend the importance of AT1 receptors to mediate physiological functions of the renin-angiotensin system.

Augmented interleukin-1beta-induced depression of locomotor activity in cholestatic rats

"Sickness behaviors" such as lethargy, fatigue, and malaise occur commonly in patients with cholestatic liver diseases and contribute significantly to the morbidity associated with these diseases. However, the cause of these symptoms is unknown. Interleukin-1beta (IL-1beta) released within the brain has been implicated in the genesis of a number of "sickness behaviors," including malaise and lethargy. Therefore, we investigated whether experimental cholestatic liver disease caused by bile duct resection (BDR) in rats is associated with enhanced central sensitivity to IL-1beta-induced "sickness behaviors." The central infusion of IL-1beta at a dose that produced an insignificant decrease in locomotor activity in control rats produced a striking reduction in locomotor activity in cholestatic rats. The anorectic response to central IL-1beta infusion was similar in cholestatic and noncholestatic animals and did not parallel our locomotor activity findings. Therefore, cholestatic liver injury is characterized by augmented central responsiveness to IL-1beta with respect to a decrease in locomotor activity. These findings may explain, at least in part, the high incidence of symptoms such as fatigue, malaise, and lethargy that occur in cholestatic patients and may open novel future avenues for their treatment.

Involvement of genes encoding a K+ channel (ether a go-go) and a Na+ channel (smellblind) in Drosophila olfaction

We have investigated the roles of the putative cyclic nucleotide-modulated K+ channel subunit encoded by the ether a go-go (eag) gene and a voltage-gated Na+ channel, smellblind (sbl), encoded by the paralytic (para) locus in odorant responsiveness and cell excitability in Drosophila melanogaster. Three independent mutant alleles of eag revealed reduced antennal responsiveness in adult flies to a subset of odorants, all having short aliphatic side chains: ethyl butyrate (EB), propionic acid, 2-butanone and ethyl acetate (manuscript submitted). Loose patch recordings revealed that significantly fewer eag antennal neurons responded to EB compared to control neurons. As expected if Eag were involved in odor transduction, fewer EB-induced inhibitory responses were observed in eag mutants and focal application of high K+ saline to sensillae altered the excitability of the majority of neurons from wild-type, but not eag, antennae. Interestingly, there were fewer excitatory odorant responses dependent on extracellular Ca2+ in eag neurons. In contrast to the involvement of Eag in adult olfactory neuron odorant transduction, we found no evidence that adult sbl and allelic olfactory D (olfD) gene mutants were defective in their behavioral response to a complex attractive odor. Furthermore, electrophysiological analyses of adult sbl and olfD mutants revealed normal electroantennogram responses to a broad range of individual pure odorants and no changes in the excitable properties of olfactory neurons as determined by loose patch recordings.

Establishment of drug chests in commune health stations in Vietnam, Bamako Initiative

In remote areas in Vietnam essential drugs are often not available. Some of the reasons are inadequate resources and failure of distribution. All activities at the health stations are very weak, partly because of inappropriate usage of drugs and lack of fund for buying drugs. The object of the project was to establish sustainable provision of essential drugs for commune health stations in rural areas, to teach the health personnel the importance of essential drugs and to create incentives for the staff and a certain surplus for other health activities. Four District Health Centers (DHC) and 10 Health Stations (HS), 2-4 in each DHC were selected. A pharmacist was made monitor of the project. The health personnel were trained in proper use of drugs, drug prescription, price setting, book keeping and management of pharmacy. Written guidelines were produced. One person was responsible for the drug chest at each HS. After recognizing the aim of the project and signing the contract by which the responsible person was bound, the initial capital was given free. The DHC was responsible for the supervision and advice to the HS. Reporting on prescribed drugs, buying and selling price, profit and fund left took place monthly. Monitoring of recovery of capital, turnover rate, rate of essential drugs and incentives for staff were monitored on forms and quarterly collected by the monitor on his visits. The HS were visited half-yearly by a steering group. All ten HS had been able to establish and maintain the pharmacy and to fully recover or even increase the capital and to create a surplus. Seven out of ten HSs had a turnover rate of more than one. The rate of essential drugs sold was more than 60% in seven pharmacies. The interest rate of 18% on average was used for incentives for staff, to provide drugs for those who cannot pay and for equipment for the HS. The cooperation between the DHC and the HS became closer. Establishment of drug chests seems to be a reasonable strategy of reinforcing primary health. Much attention should be paid on training of staff, monitoring, supervision and integration of health services.

Chronic cholestasis in rats induces anhedonia and a loss of social interest

Central fatigue commonly occurs in patients with primary biliary cirrhosis (PBC) and correlates closely with depression, and cholestatic rats exhibit central fatigue. Therefore, we undertook a series of experiments in both rats with cholestasis caused by bile duct resection (BDR) and sham-resected controls (15 days after surgery) to determine if experimental cholestasis is associated with symptoms of depression that can be modeled in rats, namely anhedonia (loss of pleasure) and the loss of social interest. BDR rats exhibited significant anhedonia compared with sham controls as indicated by a loss in their preference for consuming a saccharin solution, a highly desirable drink for rats. Furthermore, social interest was examined by determining the time BDR or sham rats spent investigating a juvenile rat in an open-field apparatus compared with the time spent on nonsocial behaviors. BDR rats exhibited significantly reduced time spent in social investigation and significantly more time in nonsocial behaviors than did sham rats. Major depression in humans is often associated with elevated circulating glucocorticoid levels and impaired glucocorticoid feedback. Therefore, we measured these parameters in BDR and sham rats and found a striking elevation in circulating glucocorticoid levels in BDR compared with sham animals. However, elevated circulating glucocorticoid levels in BDR rats suppressed normally in response to exogenous dexamethasone, indicating intact glucocorticoid feedback control at the pituitary level in BDR rats. In summary, we have identified behaviors in cholestatic rats that are consistent with those seen in depression.

Panniculectomy: a useful technique for the obese patient undergoing gynecological surgery

OBJECTIVES

To establish the safety and efficacy of panniculectomy at the time of surgery for benign and malignant gynecological disease.

METHODS

Retrospective review of the course of 57 patients undergoing radical gynecological surgery and panniculectomy between January 1992 and January 1997 at the Mercy Hospital for Women, Melbourne. Data were collected regarding indication for treatment, operative details, and complications of surgery.

RESULTS

Of 57 patients in the study, 32 had a primary gynecological malignancy, 11 had benign gynecological disease, 3 had cervical dysplasia, 5 had endometrial hyperplasia, and the remaining 6 had incisional hernia repair. The mean age of patients was 55 years with a mean weight of 101 kg (range 70-145 kg). The mean operative time was 2 h 24 min, and blood transfusion was undertaken in 23 (41%) patients. Four (7.1%) individuals had a minor wound infection and 3 (5.4%) a moderate wound infection. One patient experienced a nonfatal pulmonary embolus and 2 patients experienced a deep vein thrombosis. There were no postoperative deaths. Long term, 6 patients developed an incisional hernia.

CONCLUSIONS

Panniculectomy is a useful technique in obese patients. It improves surgical access facilitating radical surgery and is cosmetically pleasing to the patient. It has acceptable morbidity when compared to conventional midline vertical or transverse incisions in comparable populations.

SMN oligomerization defect correlates with spinal muscular atrophy severity

Spinal muscular atrophy (SMA) is a motor-neuron disorder resulting from anterior-horn-cell death. The autosomal recessive form has a carrier frequency of 1 in 50 and is the most common genetic cause of infant death. SMA is categorized as types I-III, ranging from severe to mild, based upon age of onset and clinical course. Two closely flanking copies of the survival motor neuron (SMN) gene are on chromosome 5q13 (ref. 1). The telomeric SMN (SMN1) copy is homozygously deleted or converted in >95% of SMA patients, while a small number of SMA disease alleles contain missense mutations within the carboxy terminus. We have identified a modular oligomerization domain within exon 6 of SMN1. All previously identified missense mutations map within or immediately adjacent to this domain. Comparison of wild-type to mutant SMN proteins of type I, II and III SMA patients showed a direct correlation between oligomerization and clinical type. Moreover, the most abundant centromeric SMN product, which encodes exons 1-6 but not 7, demonstrated reduced self-association. These findings identify decreased SMN self-association as a biochemical defect in SMA, and imply that disease severity is proportional to the intracellular concentration of oligomerization-competent SMN proteins.

In situ hybridization analysis of the expression of human telomerase RNA in normal and pathologic conditions of the skin

Human telomerase RNA (hTER) expression in skin was examined by in situ hybridization analysis. All newborn foreskins examined (n = 5) expressed hTER in epidermal basal cells at moderate levels. Telomerase RNA was not detectable in most adult specimens from sun protected areas (six of seven), whereas all samples obtained from sun exposed areas (n = 8) showed moderate hTER signals in epidermal basal cells. Telomerase RNA was also detected at moderate to strong levels in basal cells of psoriasis, contact dermatitis, and the proliferative cells of the anagen hair bulb. Basal cell carcinoma samples (14 of 15) had moderate to high hTER expression throughout the entire tumor, whereas squamous cell carcinomas (seven of eight) showed variable intensities of hTER expression but only in the cells at the periphery of tumor nests. All melanomas examined (n = 5) had moderate hTER expression in all tumor cells. The hTER signal intensities in skin tumors did not correlate with the age or sex of the donors, the clinical history of the lesions, or the histologic subtypes. To address whether hTER expression correlated with the proliferative state, sequential sections were stained with anti-Ki-67 antibody, a proliferation marker. In newborn foreskins, squamous cell carcinomas, and basal cell carcinomas, the distributions of hTER and Ki-67 were similar but not always identical. Telomerase RNA was more abundant than Ki-67 in the basal and suprabasal layer of newborn foreskins, suggesting that hTER expression is present both in actively cycling and in resting cells.

Point prevalence of secretory otitis media in children in southern Vietnam

Few reliable data exist on the prevalence of secretory otitis media (SOM) in the Third World. A large epidemiologic cross-sectional study was undertaken in two communes in southern Vietnam to study an urban and a rural community during two different climatic conditions: the dry and rainy seasons. The participants included 3,300 children (6,598 ears) ages 6 months to 10 years. Otolaryngological and medical histories were obtained, and an otolaryngological examination was carried out on 1,669 children in April 1995 (the dry season) and on 1,631 children in December 1995 (the rainy season). Tympanograms were obtained (n = 6,055), 429 of which were type B curves. The overall prevalence of SOM was 7.1%, the highest incidence was at the age of 2 years (with a prevalence of 22%), and there was a significantly higher prevalence of SOM during the rainy season than during the dry season. No significant difference in incidence was found in the urban district as compared to the rural district.

The impact of the quantity of skeletal injury on mortality and pulmonary morbidity

OBJECTIVE

To determine if the quantity of skeletal injuries (and the timing to fixation) increases the mortality or pulmonary morbidity in patients with and without chest injuries.

DESIGN

Retrospective analysis of trauma registry. Statistical analysis with multiple logistic regression and chi(2) analysis.

METHODS

Looking specifically at adult patients (> 16 years), skeletal injury was quantified by determining the presence or absence of a fracture in specific body regions (humeri, forearm, femur, tibia, spine, and pelvis) for a maximum of 10 skeletal injuries. The timing of fixation for fractures was categorized as < 24 hours, < 48 hours, < 72 hours, < 5 days, > 5 days, or no fixation. Chest injuries and pulmonary morbidity were based on the accepted list of complications reported in the literature.

RESULTS

Three groups were analyzed according to the presence or absence of a chest or skeletal injury: those without skeletal injury (group NSI, n = 59), those without chest injuries (group NCI, n = 108), and those with both skeletal and chest injuries (group B, n = 59) Pulmonary Complications: When all patient groups (NCI, NSI, and B) were pooled, greater chest injury (p < 0.0008), greater skeletal injury (p < 0.02), and delayed fixation (p < 0.04) were associated with increased risk of developing a pulmonary complication. In the group of patients without a chest injury (NCI), this risk was associated with greater head injury (p < 0.005) and greater skeletal injury (p < 0.04), whereas in the group without a skeletal injury (NSI), only chest injury demonstrated significance (p < 0.05). When both skeletal and chest injuries were present, greater head injury (p < 0.03) and fixation time (p < 0.03) increased the risk of developing a pulmonary complication. Mortality: With all patients pooled (NCI, B, and NSI), head injury (p < 0.02), abdominal injury (p < 0.012), and fixation time (p < 0.01) were risk factors. In patients without a chest injury (NCI), none of the indexed variables were associated with mortality. In patients without a skeletal injury (NSI), greater head injury (p < 0.01), greater chest injury (p < 0.01), and greater abdominal injury (p < 0.04) were risk factors for mortality. When both chest and skeletal injuries were present (B), only head injury (p < 0.0003) was associated with mortality. The prevalence of mortality and pulmonary complications were compared between groups NCI, NSI, and B. Group NCI had fewer pulmonary complications (p < 0.004) than the other groups (difference not significant). When examining mortality, group NCI had less mortality than groups NSI and B.

CONCLUSION

The combination of skeletal and chest injuries does not seem to amplify the pulmonary morbidity and mortality compared with chest injury alone. The quantity of the skeletal injury and the time to fixation of structures affecting mobilization seem to have an effect on pulmonary morbidity and mortality. Better scientific studies on the effects of skeletal injury and timing to fixation in relation to pulmonary morbidity and mortality are required.

Semaphorin III can repulse and inhibit adult sensory afferents in vivo

During development, semaphorins (collapsin, fasciclin) mediate repulsive and inhibitory guidance of neurons. Semaphorin III, a secretable member of this family, is expressed by the ventral spinal cord at the time corresponding to projection of sensory afferents from the dorsal root ganglion (DRG) into the spinal cord. The inhibitory effect of E14 ventral cord is active only on nerve growth factor (NGF)-responsive sensory afferents (small-diameter A-delta and C fibers subserving sensations of temperature and pain). Similarly, COS cells secreting recombinant semaphorin III are able to selectively repel DRG afferents whose growth is stimulated by NGF and not NT-3. However, it is not known whether these molecules can exert a functional role in the fully developed adult peripheral nervous system. In this study, we demonstrated that gene gun transfection and production of semaphorin III in corneal epithelial cells in adult rabbits in vivo can cause repulsion of established A-delta and C fiber trigeminal sensory afferents. In addition, it is shown that, following epithelial wounding and denervation, semaphorin III is able to inhibit collateral nerve sprouts from innervating the reepithelialized tissue. These findings are significant in that they provide direct evidence that small-diameter adult sensory neurons retain the ability to respond to semaphorin III. In addition, the corneal gene gun technique may be generally used to study the in vivo effects of neural growth modulators by quantifying the amount of sensory nerve growth.

Does debulking surgery improve survival in biologically aggressive ovarian carcinoma?

Aggressive tumor reduction surgery has been widely used in patients with advanced stage epithelial ovarian carcinoma before initiation of cytotoxic chemotherapy. No randomized controlled trial has been carried out to confirm the benefits of such procedures. To examine the role of cytoreductive surgery in the management of stage 2 and 3 patients with epithelial ovarian carcinoma treated with postoperative adjuvant platinum-based chemotherapy, survival analysis was carried out on patients with initial microscopic disease documented on staging laparotomies, patients with large volume of disease at time of exploration and tumor reduced to microscopic residuals, and patients who were suboptimally debulked with more than 2-cm residual disease. Twenty-four, 81, and 191 patients were identified from a computerized data base, respectively. Kaplan-Meier survival estimates showed that 62% with initial microscopic residual are alive with no evidence of disease at 5 years and 56% of patients left with microscopic residuals after tumor reduction are alive and well at 5 years. There was no statistical significant difference between these two groups. The groups are equivalent with respect to known adverse prognostic factors. In contrast, 5-year survival in the suboptimal debulked group was significantly lower at 15%. Debulking surgery to achieve microscopic residual disease improved the prognosis in patients with initial large volume of disease. Survival was similar to survival in patients with microscopic disease at time of exploration. The beneficial effect may be attributed to the removal of chemoresistant clones in bulky tumors. Tumor reduction surgery remains important in the management of advanced stage epithelial ovarian carcinoma.

Utility of magnetic resonance imaging in a patient with anomalous origin of the right coronary artery, acute myocardial infarction, and near-sudden cardiac death

A 46-year-old female presented with an acute myocardial infarction and cardiac arrest. Coronary angiography revealed an anomalous origin of the right coronary artery coursing between the aorta and pulmonary artery. Magnetic resonance imaging confirmed the life-threatening nature of this anomaly and led to referral for surgical revascularization.

Controlled gene gun delivery and expression of DNA within the cornea

Selective delivery of genes to ocular tissues in vivo has been a long sought after goal for potential gene therapy of ocular disease. The gene gun was considered for this purpose because of its ability to focally transfer DNA to cells through gold microparticles coated with DNA. Through experimentation, we optimized a technique that allows focal delivery and expression of a plasmid encoding green fluorescent protein in the corneal epithelium 100% of the time. Though the corneal epithelium has a delicate structure, this introduction was not associated with any corneal or ocular damage and did not produce any apparent ocular irritation. These findings demonstrate the utility of gene gun delivery of DNA to selected ocular tissues for potential experimental and therapeutic purposes.

Effects of retinoid X receptor-selective ligands on proliferation of prostate cancer cells

BACKGROUND

Management of prostate cancer that either is detectable by prostate specific antigen (PSA) measurements after curative intent or has spread outside of its capsule is a serious problem. Innovative, nontoxic approaches to the disease are required. One approach might be therapy with retinoids. Retinoid activities are mediated by two distinct families of transcription factors: the retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which can induce transcriptional activation through specific DNA sites or by inhibiting the transcription factor AP-1 that usually mediates cellular proliferative signals. The RARs require heterodimerization with RXRs. RXRs can form either heterodimers or homodimers; and the latter can bind to DNA response elements that are distinct from those bound by the RAR/RXR heterodimers.

METHODS

A series of novel synthetic retinoids that selectively interact with RXR/RXR homodimers or RAR/RXR heterodimers, or that selectively inhibit AP-1 activity without activating transcription were evaluated for their ability to inhibit clonal growth of three human prostate cancer cell lines (PC-3, DU-145, and LNCaP).

RESULTS

Several notable findings were: 1) RXR-selective retinoids, such as SR11246, were able to inhibit the clonal growth of prostate cancer cells. In contrast, SR11246 had little effect on clonal growth of myeloid leukemic cells. 2) RAR-selective retinoids also inhibited clonal growth of prostate cancer cells. 3) The retinoid (SR11238) with potent anti-AP-1 activity had no effect on the clonal growth of prostate cancer cells.

CONCLUSIONS

This study shows that both RXR- and RAR-selective retinoids are worthy of further study and may be candidates for future clinical trials in prostate cancer.

Regulation of interleukin-10 gene expression: possible mechanisms accounting for its upregulation and for maturational differences in its expression by blood mononuclear cells

Interleukin-10 (IL-10) downmodulates phagocytic immune responses and accentuates humoral responses. Human neonates exhibit broad immune deficits that parallel actions of IL-10. We postulated that IL-10 production would be diminished in neonatal blood cells. We found that IL-10 production by lipopolysaccharide-stimulated peripheral blood mononuclear cells (PBMNCs) in vitro was greater by adult cells than by term cells and preterm cells. Additional studies were undertaken to identify mechanisms responsible for the developmental differences in IL-10 gene expression. IL-10 transcription was present in freshly isolated adult and neonatal cells in the absence of detectable levels of transcript. Transcription rates were not different between adult and neonatal cells. IL-10 transcripts were approximately 40% more abundant in adult cells than in term cells and were consistent with differences in secreted protein; however, no differences were noted in mRNA stability. IL-10 half-life was 60 minutes for both adult and term PBMNCs. We conclude that up-regulation of IL-10 gene expression in PBMNCs is modulated at the post-transcriptional level, that IL-10 protein production and mRNA content are greater in activated cells from adults compared with those from neonates, and that maturational differences in IL-10 expression are not due to differences in transcription rate or mRNA stability. Maturational differences in IL-10 expression might be due to differences in subpopulations of cytokine-producing cells or differences in nucleo-cytoplasmic transport.

Malignant mixed mesodermal ovarian tumor treatment and prognosis: a 20-year experience

Mixed mesodermal sarcoma of the ovary is a rare clinical entity. To review the epidemiology, prognostic factors, and treatment results related to primary ovarian sarcoma at our center, a retrospective chart review of all patients referred for ovarian cancer was carried out from 1974 to 1994. Cases with confirmed pathologic diagnosis of primary mixed mesodermal ovarian sarcomas were selected, forming the present study group. Thirty-six charts were identified. The median age at presentation was 67.5 years. Findings at laparotomy demonstrated extraovarian metastasis in 33/35 patients. Total abdominal hysterectomy and bilateral salpingo-oophorectomy +/- omentectomy were performed in 34 patients, with 22 patients left with macroscopic residual disease after surgery. Follow-up adjuvant chemotherapy consisting of cisplatin and doxorubicin was administered to 29/36 patients. Follow-ups ranged from 1 to 11 years with a median of 2 years. As with epithelial ovarian cancer, residual disease after initial surgery is an important prognostic factor. Thirteen patients had a second-look laparotomy. Five patients were positive for disease. Eight patients, one of whom recurred, were histologically negative. The patients with positive second-look findings, as well as all those who recurred clinically, subsequently died within 12 months despite trials with different second-line chemotherapeutic agents. Survival analysis showed a median survival of 3 years among patients treated with combination cytotoxic chemotherapy. Primary ovarian sarcomas make up about 2-3% of all ovarian cancer cases seen in our center. These are often very aggressive tumors with widespread metastasis at the time of presentation, making optimal tumor debulking difficult. The combination of cisplatin and doxorubicin appears to have activity resulting in a survival of 35% at 5 years. Second-look surgery offers little helpful information on the management of these tumors.

Hypothalamic nitric oxide synthase is depressed in cholestatic rats

We examined hypothalamic nitric oxide synthase (NOS) levels and release as well as steady-state mRNA levels in rats with cholestasis due to bile duct resection (BDR) and in sham-resected control rats. BDR rats had a significant reduction in hypothalamic NOS-containing neurons in the hypothalamic paraventricular nucleus as determined by NADPH-diaphorase staining, compared with sham-resected controls. In addition, NOS activity, measured indirectly by determining nitrite release from hypothalamic explants, was significantly lower in BDR rats compared with sham-resected animals. Hypothalamic steady-state NOS mRNA levels [brain constitutive NOS (bNOS)] were determined by semiquantitative reverse transcription-polymerase chain reaction and were found to be increased 1.5-fold in BDR rats compared with sham rats. In summary, BDR rats have diminished hypothalamic NOS levels and activity coupled with enhanced steady-state bNOS mRNA levels, suggesting that depressed hypothalamic NOS protein levels are due to posttranscriptional defects.

Antigen presentation by autoreactive proteolipid protein peptide-specific T cell clones from chronic progressive multiple sclerosis patients: roles of co-stimulatory B7 molecules and IL-12

To assess the role of T cell antigen (Ag) presentation in multiple sclerosis (MS), proteolipid protein (PLP) peptide reactive CD4+ T cell clones (TCCs) from MS patients and normal subjects were studied. TCCs derived from chronic progressive (CP) MS patients were able to proliferate and secret cytokines in response to PLP peptide stimulation in the absence of professional antigen presenting cells (APCs), suggesting that these T cells can simultaneously present and respond to Ags. However, they did not respond to total PLP protein, suggesting that PLP-peptide TCCs were unable to process and present the whole PLP molecule. The ability of the different TCCs to act as APCs in response to Ag stimulation did not correlate with expression of HLA-class II molecules. However, the degree of expression of B7-1 and B7-2 co-stimulatory molecules showed a significant correlation with APC capacity. Furthermore, a combination of anti-B7-1 and anti-B7-2 mAbs effectively inhibited proliferative responses as well as secretion of IL-10, IFN gamma and TGF beta induced by antigen presenting T cells. By contrast, IL-4 secretion was not affected. Finally, IL-12 significantly enhanced the efficiency of T cell Ag presentation by a pathway independent of Ag processing, suggesting that IL-12 might act as an additional co-stimulatory signal for T cell activation during T-T cell interactions. Together, these observations suggest that Ag presentation by T cells might amplify and perpetuate an autoimmune response previously initiated by professional APCs. These properties may account for progression of MS into a CP phase.

Preferential radiosensitization of G1 checkpoint-deficient cells by methylxanthines

PURPOSE

To develop a checkpoint-based strategy for preferential radiosensitization of human tumors with deficient and/or mutant p53.

METHODS AND MATERIALS

A549 human lung adenocarcinoma cell lines differing in their expression of the p53 tumor suppressor gene were produced by transduction with the E6 oncogene from human papilloma virus type 16. The cells expressing E6 (E6+) lack a G1 arrest in response to ionizing radiation, are deficient in p53 and p21 expression, and exhibit a fivefold greater clonogenic survival following 10 Gy radiation.

RESULTS

Postirradiation incubation with millimolar concentrations of the methylxanthine pentoxifylline (PTX) results in preferential radiosensitization of the E6+ cells compared to the LXSN+ vector transduced controls. There is a threefold sensitization of the LXSN+ cells and a 15-fold sensitization of the E6+ cells, which results in equal clonogenic survival of the two lines. Flow cytometry reveals PTX abrogation of the radiation induced G2 arrest for both cell lines. PTX also prolongs G1 transit for both cell lines. Preliminary results are presented using a novel methylxanthine, lisofylline (LSF), which has similar cell cycle effects on G1 and G2 and achieves differential radiosensitization at micromolar concentrations that are sustainable in humans.

CONCLUSION

This checkpoint-based strategy is a promising approach for achieving preferential radiosensitization of p53- tumors relative to p53+ normal tissues.

An analysis of sampling errors for the Demographic Health Surveys

"Sampling errors and design effects from 48 nationally representative surveys conducted under the Demographic and Health Surveys Program for a large number of variables concerning fertility, family planning, fertility intentions, child health and mortality etc. are analysed for the total sample, and for urban-rural domains, sub-national regions and various demographic and socio-economic subclasses.... At the country level, overall design effect (the ratio of actual to simple random sampling standard error) averaged over all variables and countries is around 1.5. Variation among countries is high, but less so than among variables. Urban-rural and regional differentials in design effects are small, and can be attributed to the fact that similar sample designs and cluster sizes were used across those domains within each country. Design effects for estimates over other subclasses are smaller, and tend towards 1.0 for small subclasses and differences, apart from the effect of sample weights which tends to persist undiminished across variables and subclasses." (SUMMARY IN FRE)

Health care access and preventive care among Vietnamese immigrants: do traditional beliefs and practices pose barriers?

Some have speculated that underutilization of Western health services among non-Western populations can be explained by traditional health beliefs and practices rooted deep within cultures. These beliefs and practices may act as barriers to access to and utilization of services. Among Vietnamese, in particular, a number of traditional health beliefs and practices have been identified which are said to pose barriers to Western medical care. No studies to date, however, have examined this hypothesis empirically. To examine this hypothesis, we measured traditional health beliefs and practices among Vietnamese in the San Francisco Bay area and analyzed the relationships between these factors and access to health care and use of preventive health services. The results of this study show clearly that many Vietnamese possess traditional health beliefs and practices which differ from those of the general U.S. population. Yet, the data do not support the hypothesis that these traditional beliefs and practices act as barriers to access to Western medical care or to utilization of preventive services. Being married and poverty status were the most consistent predictors of health care access. Furthermore, the components of access to health care (having some form of health insurance or having a regular doctor, for example) were the strongest predictors of preventive health care services utilization. Importantly, the cultural attributes of individuals did not explain either lack of health care access or underutilization of preventive health care services.

Functional and physical interactions between the Epstein-Barr virus (EBV) proteins BZLF1 and BMRF1: Effects on EBV transcription and lytic replication

The Epstein-Barr virus (EBV) proteins BZLF1 and BMRF1 are both essential for lytic EBV replication. BZLF1 is a transcriptional activator which binds directly to the lytic origin of replication (oriLyt) and plays a critical role in the disruption of viral latency. The BMRF1 protein is required for viral polymerase processivity. Here we demonstrate that the BMRF1 gene product functions as a transcriptional activator and has direct (as well as indirect) interactions with the BZLF1 gene product. The BMRF1 gene product activates an essential oriLyt promoter, BHLF1, but does not activate two other early EBV promoters (BMRF1 and BHRF1). Direct interaction between the BMRF1 and BZLF1 gene products requires the first 45 amino acids of BMRF1 and the bZip domain of BZLF1. The effect of the BZLF1-BMRF1 interaction on early EBV transcription is complex and is promoter specific. The oriLyt BHLF1 promoter is activated by either the BZLF1 or BMRF1 gene product alone and is further activated by the combination of the BZLF1 and BMRF1 gene products. Enhanced activation of BHLF1 transcription by the BMRF1-BZLF1 combination does not require direct interaction between these proteins. In contrast, BZLF1-induced activation of the BMRF1 promoter is inhibited in the presence of the BMRF1 gene product. A point mutation in the BZLF1 protein (amino acid 200), which prevents in vitro interaction with the BMRF1 protein but which does not reduce BZLF1 transactivator function, allows the BZLF1 protein to activate the BMRF1 promoter equally well in the presence or absence of the BMRF1 gene product. Therefore, direct interaction between the BZLF1 and BMRF1 proteins may inhibit BZLF1-induced transcription of the BMRF1 promoter. BZLF1 mutated at amino acid 200 is as efficient as wild-type BZLF1 in promoting replication of an oriLyt plasmid. However, this mutation reduces the ability of BZLF1 to induce lytic replication of the endogenous viral genome in D98/HE-R-1 cells. Our results indicate that functional and physical interactions between the BMRF1 and BZLF1 proteins may modulate the efficiency of lytic EBV infection. The BMRF1 gene product clearly has a transcriptional, as well as replicative, role during lytic EBV infection.

Phylogenetic characterization of the epithelial Na+ channel (ENaC) family

Twenty-one sequenced protein members of the epithelial Na+ channel (ENaC) family have been identified and characterized in terms of their sizes, hydropathy profiles, sequence similarities and phylogenies. These proteins derive from mammals, the frog Xenopus laevis and the worm Caenorhabditis elegans. The eleven sequenced vertebrate proteins fall into four subfamilies designated alpha, beta, gamma and delta. The 10 C. elegans proteins do not cluster with the vertebrate proteins, and they all proved to be distantly related to each other. Nonetheless, the 21 ENaC proteins exhibit the same apparent topology, each with two transmembrane spanning segments separated by a large extracellular loop. All but two ENaC proteins possess highly conserved extracellular domains containing numerous conserved cysteine residues as well as adjacent C-terminal amphipathic transmembrane spanning segments, postulated to contribute to the formation of the hydrophillic pores of these oligomeric channel protein complexes. It is proposed that the well-conserved extracellular domains serve as receptors to control the activities of the channels. A topological model for the ENaC family proteins is presented.

Pattern of utilization of rifabutin for prophylaxis of Mycobacterium avium complex among patients with advanced human immunodeficiency virus disease in a community setting

OBJECTIVE

To characterize the pattern of utilization, effectiveness, and safety profile of rifabutin for Mycobacterium avium complex (MAC) prophylaxis among individuals with advanced human immunodeficiency virus disease in a community setting.

METHODS

Individuals who, while registered in the provincial drug distribution program, had at least one CD4 count below 100 cells/mm3 for the period 1 May 1993 to 31 March 1994 were included. MAC diagnoses were identified through a record linkage with the mycobacterial reference laboratory of the Provincial Centre for Disease Control. In order to determine the occurrence of adverse events, a survey was sent in March 1994 to the 98 primary care physicians prescribing rifabutin prophylaxis in the province. We achieved 100% response rate to the survey.

RESULTS

During the study period 515 patients in our drug treatment program were eligible to receive MAC prophylaxis. Of these, 340 (66%) were being prescribed rifabutin as recommended by current guidelines. Rifabutin prophylaxis use was significantly associated with use of antiretroviral therapy. The product limit estimate of the cumulative incidence of MAC at 10 months was 13.0% among those receiving rifabutin prophylaxis. Diagnosis of MAC was significantly associated with a lower baseline CD4 count (cumulative incidence 7.1% and 18.1% for CD4 > or = 50 and < 50 cells/mm3, respectively, P = 0.01). A total of four cases of uveitis, eight cases of pseudo-jaundice, and five cases of arthralgia in 16 patients were identified by our survey.

CONCLUSION

Our data demonstrates that rifabutin prophylaxis of MAC is being used by approximately 66% of eligible individuals. Rifabutin use was associated with antiretroviral use, which may reflect individuals' attitudes towards medications. Our intention-to-treat analysis, with a 10 month cumulative MAC incidence of 13.0% among those receiving rifabutin prophylaxis, is in keeping with break-through rates previously reported in the context of clinical trials. Our results also support previous observations that the risk of MAC infection greatly increases at CD4 counts < 50 cells/mm3. Rifabutin prophylaxis was generally well-tolerated in our program.