Chromosomal localization of ESTs obtained from human fetal liver via BAC-mediated FISH mapping

A total of 55 expressed sequence tags (ESTs) randomly chosen from our collection of fetal liver ESTs were mapped to chromosomes by fluorescence in situ hybridization (FISH) mapping techniques. To generate FISH mapping probes, the genomic DNAs for each EST were selected by screening an arrayed human bacterial artificial chromosome (BAC) library. In total, 73 BACs were used for mapping of the 55 ESTs. Among them, 70 BACs representing 52 ESTs unequivocally mapped to single chromosomal regions. The remaining 3 BACs representing 3 ESTs were localized to multiple regions, suggesting that BACs may have very low chimerism. Our mapping results were compared with EST mapping databases deposited in NCBI. Thirty-six of 55 ESTs corresponded to previously mapped positions of ESTs, 2 ESTs mapped to different positions from previously determined ones, and it was found that 17 ESTs have been mapped on new locations from this study. These mapping data may be used for completing the framework of the human physical map, and also for providing a good starting point for searching disease-related genes.

Glibenclamide induces apoptosis through inhibition of cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channels and intracellular Ca(2+) release in HepG2 human hepatoblastoma cells

Glibenclamide, an inhibitor of cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channels, induced apoptosis in a dose- and time-dependent manner in HepG2 human hepatoblastoma cells. Glibenclamide increased intracellular Ca(2+) concentration, which was significantly inhibited by Ca(2+) release blockers dantrolene and TMB-8. BAPTA/AM, an intracellular Ca(2+) chelator, and the Ca(2+) release blockers significantly inhibited glibenclamide-induced apoptosis. Glibanclamide also increased intracellular Cl(-) concentration, which was significantly blocked by CFTR Cl(-) channel activators levamisole and bromotetramisole. These activators also significantly inhibited both intracellular Ca(2+) release and apoptosis induced by glibenclamide. The expression of CFTR protein in the cells was confirmed by Western blot analysis. These results suggest that glibenclamide induced apoptosis through inhibition of CFTR Cl(-) channels and intracellular Ca(2+) release and that this protein may be a good target for treatment of human hepatomas.

Inhibitory effects of constituents of Gastrodia elata Bl. on glutamate-induced apoptosis in IMR-32 human neuroblastoma cells

The inhibitory effects of the constituents of Gastrodia elata Bl. (GE) on glutamate-induced apoptosis in human neuronal cells were investigated using IMR32 human neuroblastoma cells. Glutamate (GLU) induced DNA fragmentation, a hallmark of apoptosis, in a dose-dependent manner. GLU also induced a slow and sustained increase in intracellular Ca2+ concentration. Treatment with EGTA, an extracellular Ca2+ chelator, in a nominal Ca2+-free buffer solution abolished the GLU-induced intracellular Ca2+ increase, indicating that GLU stimulated Ca2+ influx pathway in the IMR32 cells. BAPTA, an intracellular Ca2+ chelator, significantly inhibited the GLU-induced apoptosis assessed by the flow cytometry measuring hypodiploid DNA content indicative of apoptosis, implying that intracellular Ca2+ rise may mediate the apoptotic action of GLU. Vanillin (VAN) and p-hydroxybenzaldehyde (p-HB), known constituents of GE, significantly inhibited both intracellular Ca2+ rise and apoptosis induced by GLU. These results suggest that the apoptosis-inhibitory actions of the constituents of GE may account, at least in part, for the basis of their antiepileptic activities. These results further suggest that intracellular Ca2+ signaling pathway may be a molecular target of the constituents of GE.

TNF-alpha-mediated apoptosis is initiated in caveolae-like domains

Caveolae-like domains (CLDs) have been hypothesized to mediate apoptosis, since they contain sphingomyelin and initiate the conversion of sphingomyelin to ceramide. To address whether CLDs are directly involved in apoptosis, CLDs from U937 cells were isolated, taking advantage of their detergent insolubility and low density. The CLDs contained alkaline phosphatase as well as many signaling molecules, including Fyn, protein kinase Calpha, Raf-1, phospholipase Cgamma1, and tyrosine phosphoproteins. Immunoblotting and immunofluorescent data showed that TNF receptor 1 colocalized with CD36 in CLDs, suggesting that TNF-alpha-initiated apoptosis occurs in CLDs. When cells were incubated with lipoprotein-deficient medium, the cholesterol concentration was greatly decreased in CLDs but not in other fractions, implying that the CLDs were selectively disrupted. In the CLD-disrupted cells, the surface expression of TNF receptor 1 and CD36 was significantly reduced. Analysis of cellular morphology, percent DNA fragmentation, DNA laddering, and caspase-3 activity showed that TNF-alpha-mediated apoptosis was blocked in CLD-disrupted cells, whereas anti-Fas-mediated apoptosis was not. Since Fas was not found in CLDs of Jurkat cells, apoptosis by Fas ligation might not require CLDs. Taken together, these data strongly imply that TNF-alpha-mediated apoptosis is initiated in CLDs.

Suppression of ceramide-mediated apoptosis by HSP70

Ceramide has been known as an important second messenger in programmed cell death (apoptosis) which is induced by various stimuli such as the tumor necrosis factor-alpha (TNF-alpha), Fas ligand, and environmental stresses such as UV-irradiation and heat shock. Although the precise molecular mechanism of apoptosis is not fully understood, ceramide generated by sphingomyelinase (SMase) mediates the activation of several downstream molecules that are implicated in the regulation of apoptosis. Here, we show that stress-inducible heat shock protein 70 (Hsp70) prevents apoptosis induced by increased level of intracellular ceramide. In T-cell hybridoma DO11.10, we examined the effect of Hsp70 on apoptosis mediated by TNF-alpha, Fas ligation, SMase, and C2-ceramide, all of which elevate intracellular ceramide levels. Hsp70 not only markedly reduced internucleosomal DNA fragmentation, but also enhanced cell viability measured by the Trypan blue dye exclusion test. Similarly, the ceramide-induced c-jun amino-terminal kinase (JNK/SAPK) activation is impaired in cells overexpressing Hsp70. These data strongly suggest that hsp70 functions as a regulator of apoptosis downstream of ceramide.

Permeability of a capsaicin derivative, [14C]DA-5018 to blood-brain barrier corrected with HPLC method

In the present work, the transport mechanism of a capsaicin derivative, DA-5018, through blood-brain barrier (BBB) has been investigated to evaluate the feasibility of potential drug development. The result of pharmacokinetic parameters obtained from the intravenous injection of plasma volume marker, [3H]RSA and [14C]DA-5018, indicated that both AUC, area under the plasma concentration curve and VD, volume of distribution in brain of [3H]RSA agreed with those reported (1620 +/- 10 percentage injected dose minute per milliliter (%IDmin/ml) and 12.0 +/- 0.1 microliters/g, respectively). Elimination half-life and AUC of [14C]DA-5018 is corrected by the HPLC analysis, 19.6 +/- 1.2 min and 7.69 +/- 0.85% IDmin/ml, respectively. The metabolic rate of [14C] DA-5018 was very rapid. The blood-brain barrier permeability surface area (PS) product of [14C]DA-5018 was calculated to be 0.24 +/- 0.05 microliter/min/g. The result of internal carotid artery perfusion and capillary depletion suggested that [14C]DA-5018 pass through BBB with the time increasingly. Investigation of transport mechanism of [14C]DA-5018 using agonist and antagonist suggested that vanilloid (capsaicin) receptor did not exist in the BBB, and nutrient carrier system in the BBB has no effect on the transport of DA-5018. In conclusion, despite the fact that penetration of DA-5018 through BBB is significant, the intact drug found in the brain tissue is small because of a rapid metabolism. Therefore, for the central analgesic effect of DA-5018, the method to increase the metabolic stability in plasma and the brain permeability should be considered.

Role of Ca2+ influx in the tert-butyl hydroperoxide-induced apoptosis of HepG2 human hepatoblastoma cells

Oxidative stress appears to be implicated in the pathogenesis of various diseases including alcoholic liver injury. In this study we investigated the mechanism of apoptosis induced by tert-butyl hydroperoxide (TBHP) in HepG2 human hepatoblastoma cells. Treatment with TBHP significantly reduced glutathione content and glutathione reductase activity, and increased glutathione peroxidase activity, indicating that TBHP induced oxidative stress in the HepG2 cells. TBHP also induced reduction of cell viability and DNA fragmentation, a hallmark of apoptosis, in a dose-dependent manner. In addition, TBHP induced a sustained increase in intracellular Ca2+ concentration, which was completely prevented by the extracellular Ca2+ chelation with EGTA. TBHP also induced Mn2+ influx. These results indicate that the intracellular Ca2+ increase by TBHP is exclusively due to Ca2+ influx from the extracellular site. Treatment with either an extracellular (EGTA) or an intracellular Ca2+ chelator (BAPTA/AM) significantly suppressed the TBHP-induced apoptosis. Taken together, these results suggest that TBHP induced the apoptotic cell death in the HepG2 cells and that Ca2+ influx may play an important role in the apoptosis induced by TBHP.

Electroretinographic evaluation in adult diabetics

In cross-sectional fashion, we recorded the maximal combined response and 30-Hz flicker responses in 178 adult diabetics and 40 normal controls according to the recommendations of the International Society of Clinical Electrophysiology of Vision. The oscillatory potentials were extracted from the maximal combined response by high-pass filtering. The clear media and attached retina were criteria for inclusion in this study. The data were statistically analyzed with the expectation that this procedure may provide a new feature that could have some clinical significance. Timing delays occurred more frequently than amplitude reductions in the maximal combined response and flicker responses, while amplitude reductions were more common in the first and second oscillatory potentials. The hypernormal b-wave amplitude was rare. The summed amplitude of the oscillatory potentials was highly correlated with the total power of the oscillatory potentials (the frequency domain). A reduction of the second oscillatory potential amplitude was more common than a reduction of the summed amplitude or total power. The electroretinographic component that demonstrates retinal dysfunction in the earlier stage may be a valuable indicator. In the early stage, a delay in the a-wave time and a reduction in the second oscillatory potential amplitude were the most frequent abnormalities: analysis of variance demonstrated that the summed amplitude of the oscillatory potentials and second oscillatory potential amplitude and time were the most sensitive measures of the diabetic retina. Hence, the second oscillatory potential amplitude may be the most sensitive and valuable indicator representing a quantitative measure of overall retinal dysfunction.

No increase in blood-brain barrier permeability after intraperitoneal injection of endotoxin in the rat

Reactions mediated by the brain are part of the response to intraperitoneal administration of endotoxin, a model of gram-negative bacterial infection. To test the hypothesis that a compromised blood-brain barrier (BBB) may contribute to these reactions, the integrity of the BBB was measured following lipopolysaccharide administration. Rats received intraperitoneal injections of 50 microg/kg or 2 mg/kg of endotoxin. Brain uptake of a macromolecular vascular marker, 3H-labelled rat serum albumin, and of a poorly permeable low molecular weight substance, [14C]sucrose, was then measured with the intravenous bolus injection method. Compared to controls, neither dose of endotoxin affected the BBB permeability for these tracers. This was true when brain uptake was measured 5 min or 2 h after lipopolysaccharide injection. It is concluded that intraperitoneal endotoxin even at a high dose does not acutely disrupt the BBB.

Multiple phosphorylation of chicken protein tyrosine phosphatase 1 and human protein tyrosine phosphatase 1B by casein kinase II and p60c-src in vitro

We have cloned a soluble chicken protein tyrosine phosphatase, named CPTP1, from the cDNA library of chicken intestine. The CPTP1 showed 92% sequence identity to the corresponding 321 amino acid residues of human PTP1B (HPTP1B). CPTP1 lacked 13 amino acids of the N-terminal region compared with HPTP1B, while the C-terminal 48 amino acid sequence of this protein was distinct from those of other PTPs. In vitro phosphorylation and phosphoamino acid analysis showed that both CPTP1 and HPTP1B were phosphorylated on serine and threonine residues near their N-terminus by casein kinase II (CKII). Furthermore, phosphorylation of CPTP1 by CKII resulted in an inhibition of its phosphatase activity in vitro. Interestingly, both CPTP1 and HPTP1B were also tyrosine-phosphorylated near their N-terminus by p60c-src. When we examined the vanadate effect, in the absence of vanadate, the tyrosine-phosphorylated CPTP1 by p60c-src was autodephosphorylated by its own phosphatase activity. These results suggest that both CPTP1 and HPTP1B might play an important role in CKII- and p60c-src-induced signal transduction cascades.

Organochlorine pesticides, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans in human adipose tissue from western Kyungnam, Korea

Hexachlorocyclohexanes (HCHs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs) were determined in human adipose tissue samples collected from western Kyungnam, Korea. The residue levels of organochlorine compounds were in the order of DDTs followed by PCBs > HCHs > HCB > PCDDs/DFs. The mean concentrations of 2,3,7,8-TeCDD in male and female tissues were 2.8 and 1.7 pg.g-1 on lipid weight basis, respectively. No significant difference was found in the residue levels of PCDDs/DFs between sexes. In contrast, PCBs and DDTs showed a significant difference between sexes. Unlike the age trend observed for HCHs, PCBs and DDTs, PCDDs/DFs revealed a constant or rather decreasing pattern with increasing age. This is the first report on PCDDs/DFs contamination in human adipose tissue from Korea. Organochlorine concentrations in human adipose tissues from western Kyungnam were generally much lower than those of other countries.

Blood-brain barrier permeability to morphine-6-glucuronide is markedly reduced compared with morphine

The blood-brain barrier (BBB) permeability to morphine and morphine-6-glucuronide (M6G) is measured under identical conditions using an intravenous injection method in the rat and HPLC separation of morphine from its metabolites. The brain uptake of M6G expressed as %ID/g was 32-fold lower than that of morphine, and the BBB permeability surface area product (PS) of M6G was 57-fold lower as compared with that of morphine. Consistent with these in vivo data, the 1-octanol/buffer partition study showed the liposolubility of M6G was 187-fold lower than that of morphine. The CNS origin of M6G analgesia after peripheral administration was confirmed because the analgesia was completely blocked by naloxone, which crosses BBB, but not by naloxone methiodide, which does not enter brain from blood. In conclusion, the BBB permeability to M6G is markedly reduced as compared with morphine, consistent with the much lower lipid solubility of M6G relative to morphine.

Nonassociation of estrogen receptor genotypes with bone mineral density and estrogen responsiveness to hormone replacement therapy in Korean postmenopausal women

Hormone replacement therapy (HRT) prevents bone loss in postmenopausal women, but some women are resistant to therapy. A recently reported case of severe estrogen resistance caused by a germline mutation at the estrogen receptor (ER) gene locus suggests the possibility that other variants of the ER gene could be responsible for resistance to HRT and could also be an answer to the heritable components of bone density. Three restriction fragment length polymorphisms (RFLPs) at the ER gene locus, represented as BstUI (or B variant), PvuII, and XbaI, and their relationship to bone mineral density (BMD) and estrogen responsiveness to HRT were examined in 248 healthy postmenopausal women, aged 41-68 yr (mean +/- SD, 52.0 +/- 4.6 yr) in Korea. The BstUI restriction site was not found in Korean women. The distribution of the PvuII and XbaI RFLPs was as follows: PP, 35 (14.1%); Pp, 136 (54.8%); pp, 77 (31.1%) and XX, 18 (7.3%); Xx, 72 (29.0%); and xx, 158 (63.7%), respectively (capital letters signify the absence of and lower case letters signify the presence of the restriction site of each RFLP). There was no significant relation between ER genotypes and z score values of lumbar spine BMD. Also, no significant genotypic differences were found in the change in lumbar spine BMD and those in biochemical markers before and after 1 yr of HRT. These data indicate no significant effects of ER genotypes on BMD and estrogen responsiveness after HRT.

Brain microvascular and astrocyte localization of P-glycoprotein

The hypothesis that P-glycoprotein plays a functional role at the brain capillary endothelium, which makes up the blood-brain barrier in vivo, is based largely on immunocytochemical studies showing immunoreactive P-glycoprotein localized to either isolated brain microvessels or microvessels within tissue sections. The present studies use the MRK16 monoclonal antibody to human P-glycoprotein to demonstrate that the pattern of immunolocalization of P-glycoprotein in microvessels of human or primate brain is similar to the pattern of immunolocalization of an astrocyte protein, glial fibrillary acidic protein. In contrast, the discontinuous staining pattern of MRK16 is not colocalized with the continuous immunostaining of the brain endothelial GLUT1 glucose transporter. The MRK16 antibody was radiolabeled with [125I]-iodine, and 125I-MRK16 avidly bound isolated human brain capillaries via a saturable mechanism. However, the 125I-MRK16 antibody was not taken up by primate brain capillaries in vivo following intravenous injection. In conclusion, these studies provide evidence that P-glycoprotein does not play a functional role at the luminal membrane of the brain capillary endothelium in vivo, and that a principal site of immunoreactive P-glycoprotein in brain microvasculature is localized to astrocyte foot processes.

Poor permeability of morphine 3-glucuronide and morphine 6-glucuronide through the blood-brain barrier in the rat

To better understand the in vivo pharmacological effects of morphine 3-glucuronide (M3G, a weak opioid antagonist) and morphine 6-glucuronide (M6G, a potent opioid agonist), the permeability of the blood-brain barrier (BBB) for these metabolites was compared with morphine. Tracers were prepared by enzymatic glucuronidation of [N-methyl-3H]morphine. Brain uptake in rats was measured by the internal carotid perfusion technique and after intravenous bolus injections. In the perfusion experiments morphine showed a permeability-surface area product (PS) of 3.52 +/- 0.61 microliter min-1 g-1. Uptake seemed to be mediated by passive diffusion and was not saturable by 100 microM morphine in the perfusate. The BBB permeability of [3H]M3G and [3H]M6G was too low to be quantified after 5 min of perfusion. Brain uptake of [3H]M3G and [3H]M6G 60 min after i.v. bolus injection reached 0.0060 +/- 0.0003% and 0.0030 +/- 0.0005% injected dose per g, respectively. From these brain concentrations and the corresponding plasma concentration-time curves, BBB PS values of 0.14 +/- 0.02 microliter min-1 g-1 and 0.11 +/- 0.01 microliter min-1 g-1, respectively, were calculated. The ratio of BBB PS values is complementary to the analgesic potencies of morphine and M6G after different routes of administration. The low PS of M6G explains why it is approximately equipotent to morphine after systemic injection, although it is about 2 orders of magnitude more potent than morphine after administration directly into the central nervous system.

Septic thrombophlebitis of the inferior mesenteric vein associated with diverticulitis CT diagnosis

Septic thrombophlebitis of a mesenteric vein can occur as a rare complication of diverticulitis. We report a case of septic thrombophlebitis of the inferior mesenteric vein diagnosed with computed tomography, in a patient with sigmoid diverticulitis.

Pathology of the rectal wall in solitary rectal ulcer syndrome and complete rectal prolapse

BACKGROUND

The aetiology and pathology of rectal prolapse and solitary rectal ulcer are poorly understood.

AIMS

To examine the full thickness rectal wall in these two conditions.

METHODS

The pathological abnormalities in the surgically resected rectal wall were studied from nine patients with solitary rectal ulcer syndrome, 11 complete rectal prolapse, and nine cancer controls. Routine haematoxylin and eosin and Van Gieson staining for collagen were performed.

RESULTS

The rectal wall from solitary rectal ulcer syndrome specimens was thickened compared with complete rectal prolapse and controls. The major difference was in the muscularis propria (2.2 v 1.1 v 1.2 mm, medians, p < 0.005) and particularly the inner circular muscular layer, and to a lesser extent the submucosal and outer longitudinal muscular layers. Some solitary rectal ulcer syndrome specimens showed unique features such as decussation of the two muscular layers (four of nine), nodular induration of inner circular layer (four of nine) and grouping of outer longitudinal layer into bundles (three of nine); these were not seen in complete rectal prolapse or control specimens.

CONCLUSIONS

These features, which resemble the features of high pressure sphincter tissue, may be of aetiological importance, and suggest a different pathogenesis for these two disorders. Excess collagen was seen in both disorders, was more severe in solitary rectal ulcer syndrome specimens, and probably reflects a response to repeated trauma.

Cationized hyperimmune immunoglobulins: pharmacokinetics, toxicity evaluation and treatment of human immunodeficiency virus-infected human-peripheral blood lymphocytes-severe combined immune deficiency mice

The in vivo pharmacokinetics and efficacy of cationized human immunoglobulins in the human-peripheral blood lymphocytes-severe combined immune deficiency mouse model were evaluated in the present studies using the severe combined immunodeficient mouse transplanted with human lymphocytes and infected with human immunodeficiency virus (HIV)-1. Immunoglobulins from noninfected humans and from HIV-infected individuals were cationized. The pharmacokinetic analysis showed that the cationized immunoglobulins have a markedly reduced mean residence time and a marked increase in organ uptake compared to the native immunoglobulins. The toxicity studies performed with homologous immunoglobulins in BALB/c mice demonstrated cationized homologous immunoglobulins have no tissue toxicity at a daily dose of 7.5 mg/kg. Treatment of HIV-infected severe combined immune deficiency mice that were transplanted with human lymphocytes demonstrated therapeutic efficacy for a 2-week treatment at a dose of 5 mg/kg cationized HIV immune globulin. In conclusion, cationized immunoglobulins are potential antibody-based therapeutics for the treatment of acquired immune deficiency syndrome; cationized antibodies undergo enhanced transport into lymphocytes and when homologous cationized immunoglobulins are administered there is no measurable tissue toxicity.

Upregulation of blood-brain barrier GLUT1 glucose transporter protein and mRNA in experimental chronic hypoglycemia

An in vivo model of chronic hypoglycemia was used to investigate changes in blood-brain barrier (BBB) glucose transport activity and changes in the expression of GLUT1 mRNA and protein in brain microvasculature occurring as an adaptive response to low circulating glucose levels. Chronic hypoglycemia was induced in rats by constant infusion of insulin via osmotic minipumps; control animals received infusions of saline. The criterion for chronic hypoglycemia was an average blood glucose concentration of < 2.3 mmol/l (42 mg/dl) after 5 days. The average blood glucose concentration at the end of the experimental period in the rats selected for study was 2.0 +/- 0.1 mmol/l (36 +/- 1 mg/dl) vs. 4.9 +/- 0.1 mmol/l (88 +/- 1 mg/dl) in the controls. Internal carotid artery perfusion studies demonstrated an increase in the BBB permeability-surface area (PS) product of 40% (P < 0.0005) in the chronically hypoglycemic animals as compared with controls. Western blotting of solubilized isolated brain capillaries demonstrated a 51% increase (P < 0.05) in immunoreactive BBB GLUT1 in the chronically hypoglycemic rats, and Northern blotting of whole-brain poly(A+) mRNA revealed a 50% increase in the GLUT1-to-actin ratio in the insulin-treated group (P < 0.05). Northern blotting analysis of microvessel-depleted total brain poly(A+) showed that the increase in GLUT1 mRNA in the chronically hypoglycemic rats was restricted to the BBB. The present study demonstrates increased expression of GLUT1 mRNA and protein at the BBB in chronic hypoglycemia and suggests that this increase is responsible for the compensatory increase in BBB glucose transport activity that occurs with chronically low circulating blood glucose levels.

Loss of heterozygosity on chromosome 10, 13q(Rb), 17p, and p53 gene mutations in human brain gliomas

Using the methods of restriction fragment length polymorphism (RFLP) and single strand conformation polymorphism (SSCP) analyses, we have examined 33 cases of human gliomas with various malignant grades to detect the deletions of putative tumor suppressor gene loci, chromosome 10, 13q(retinoblastoma gene, Rb), 17p, and p53 mutation. We observed loss of heterozygosity (LOH) at loci on chromosome 10 (36%), 13q(Rb) (54%), and 17p(50%) in malignant gliomas. There, however was no allelic loss on chromosome 10 and 17p in low-grade gliomas. Rb gene deletions were seen in low-grade gliomas, including oligodendroglioma and ependymoma. This finding suggests that Rb inactivation may be an early genetic event in the development and progression of gliomas. We correlated the results of LOH on chromosome 17p and p53 mutation. Among the 8 cases which showed LOH on chromosome 17p, only three cases (38%) revealed p53 mutations. Low incidence of p53 mutations in cases with chromosome 17p deletions suggests that some other tumor suppressor genes may be located on chromosome 17p.

p53 mutation in epithelial ovarian carcinoma and borderline ovarian tumor

We have investigated a series of 19 human ovarian carcinomas and 17 borderline ovarian tumors to determine the loss of heterozygosity on chromosome 17p and possible concurrent p53 mutations. Allelic losses were assessed using restriction fragment length polymorphism study, and p53 gene mutations were detected by single strand conformation polymorphism analysis and by direct sequencing. In addition, we stained the same tumor sections immunohistochemically to detect p53 protein in tissues. Among 19 ovarian malignant tumor samples tested, we identified 17p allelic deletions in 12 (63.2%) of 19 informative cases. The p53 gene mutation was observed in 7 of 19 (36.8%) malignant ovarian tumors, and it was predominantly observed in tumors with allelic loss on 17p (six of seven tumors, 85.7%). Although 9 cases of 17 borderline ovarian tumors showed shifted bands on single strand conformation polymorphism analysis, only one case was proved to have a point mutation in direct sequencing. We also obtained six cases (31.6%) of positive immunoreactivity from 19 ovarian cancers and 3 cases (17.6%) from 17 borderline ovarian tumors. We conclude that loss or inactivation of tumor suppressor gene function by chromosome 17p allelic deletions or p53 mutations are important genetic changes in ovarian cancer.

Enhanced cellular uptake and in vivo biodistribution of a monoclonal antibody following cationization

Owing to the poor transport of monoclonal antibodies across either capillary or cell membrane barriers, drug delivery strategies are needed to target monoclonal antibodies to intracellular sites where proteins function. One antibody drug delivery strategy is cationization, wherein the isoelectric point (pl) is raised by conversion of surface carboxyl groups to extended primary amino groups. The present studies describe the cationization of a murine monoclonal antibody (D146) prepared against a synthetic peptide encoding the Asp13 point mutation of the ras protooncogenic p21 protein. The pl of the D146 monoclonal antibody was raised from 8.9 to > 9.5. The uptake in vitro of the 125I-labeled native D146 antibody by MDA-MB231 human carcinoma cells was negligible, whereas there was a marked increase in the endocytosis of the antibody following cationization. In vivo pharmacokinetic analysis was performed in male BALB/c mice. The in vivo organ uptake of the cationized monoclonal antibody was increased relative to the native antibody; there was a 6-fold increase in the systemic volume of distribution, a 58-fold increase in the systemic clearance of the cationized antibody from the plasma compartment, and a 9-fold reduction in the mean residence time of the cationized antibody as compared to the native D146 antibody. In conclusion, these studies show that cationization of an oncogene-specific monoclonal antibody results in markedly increased endocytosis of the antibody by cancer cells in vitro and in increased systemic clearance and organ uptake in vivo.

Vector-mediated delivery of a polyamide ("peptide") nucleic acid analogue through the blood-brain barrier in vivo

Polyamide ("peptide") nucleic acids (PNAs) are molecules with antigene and antisense effects that may prove to be effective neuropharmaceuticals if these molecules are enabled to undergo transport through the brain capillary endothelial wall, which makes up the blood-brain barrier in vivo. The model PNA used in the present studies is an 18-mer that is antisense to the rev gene of human immunodeficiency virus type 1 and is biotinylated at the amino terminus and iodinated at a tyrosine residue near the carboxyl terminus. The biotinylated PNA was linked to a conjugate of streptavidin (SA) and the OX26 murine monoclonal antibody to the rat transferrin receptor. The blood-brain barrier is endowed with high transferrin receptor concentrations, enabling the OX26-SA conjugate to deliver the biotinylated PNA to the brain. Although the brain uptake of the free PNA was negligible following intravenous administration, the brain uptake of the PNA was increased at least 28-fold when the PNA was bound to the OX26-SA vector. The brain uptake of the PNA bound to the OX26-SA vector was 0.1% of the injected dose per gram of brain at 60 min after an intravenous injection, approximating the brain uptake of intravenously injected morphine. The PNA bound to the OX26-SA vector retained the ability to bind to synthetic rev mRNA as shown by RNase protection assays. In summary, the present studies show that while the transport of PNAs across the blood-brain barrier is negligible, delivery of these potential neuropharmaceutical drugs to the brain may be achieved by coupling them to vector-mediated peptide-drug delivery systems.