Expression of mast-cell-specific proteases in tissues of mice studied by in situ hybridization

The protease mRNA expression phenotype of individual mast cells was studied by in situ hybridization. Mouse mast cell protease (MMCP)-2 mRNA was expressed by mast cells located in the mucosa of the stomach of WB(-)+/+ and (WB x C57BL/6)F1(-)+/+ (hereafter WBB6F1(-)+/+) mice but not by mast cells in the same tissue of C57BL/ 6(-)+/+ mice. Even in the stomach of WBB6F1(-)+/+ mice, mast cells located in the muscularis propria did not express MMCP-2 mRNA. The mRNAs of MMCP-4 and mouse mast cell carboxypeptidase A were not expressed by mast cells in the stomach mucosa of untreated WBB6F1(-)+/+ mice but were expressed after the infection of Strongyloides venezuelensis. We examined whether MMCP-2 mRNA expression varied by changing environments of mast cells. Cultured mast cells of WBB6F1(-)+/+ mice that expressed MMCP-2 mRNA were transplanted into the stomach wall of genetically mast-cell-deficient WBB6F1(-)W/Wv mice. Mast cells that appeared in the mucosa expressed the MMCP-2 mRNA, but mast cells that appeared in the muscularis propria did not, indicating the adaptation of cultured mast cells into a new environment. In contrast to cultured mast cells, peritoneal mast cells of WBB6F1(-)+/+ mice that expressed MMCP-2 mRNA as well did not adapt to the muscularis propria of WBB6F(1)-W/Wv mice. The MMCP-2 mRNA remained to be expressed after the settlement in either the mucosa or the muscularis propria. Furthermore, the peritoneal mast cells did not change the MMCP-4 and MMCP-6 mRNA expression phenotype after the settlement in either the mucosa or the muscularis propria of WBB6F(1)-W/Wv mice. The present result indicated that both intracellular factors such as strain specificity and source of mast cells and extracellular factors such as tissue specificity and helminth infection influenced the protease expression phenotypes.

Endoscopic laser-assisted dacryocystorhinostomy

PURPOSE

This study evaluates the efficacy of endoscopic laser-assisted dacryocystorhinostomy (LADCR) in the treatment of epiphora and chronic dacryocystitis.

PATIENTS AND METHODS

Treatment results were prospectively reviewed for 17 patients undergoing 19 LADCR procedures of which 12 were primary and 7 were revision cases. Silastic intubation tubing was removed after surgery at a mean of 76.5 days in the primary cases and 184 days in the revision cases. Patients were followed-up for a mean of 15.6 months (range, 5 to 25 months).

RESULTS

LADCR was successful in 100% of primary cases and 60% of revision procedures. The only complications were 2 conjunctival fistula, which closed without sequela.

CONCLUSION

The efficacy of primary LADCR is comparable to reported external approaches. The success of revision LADCR is less favorable, yet the number of cases reported here is too small to reach a conclusion.

Biological effects of drug-loaded biodegradable membranes for guided bone regeneration

The biological effects of drug-loaded biodegradable novel membrane for guided bone regeneration (GBR) was evaluated. The membranes were polyglycolic acid mesh coated with poly-L-lactic acid containing flurbiprofen, tetracycline or PDGF-BB. Porous structure was generated in the membranes by using a phase inversion method. The membrane was less toxic, nicely biodegradable and biocompatible for 8 wk after implantation in the dorsal skin of the rat. The drugs released from the membranes were shown to be effective for new bone formation. Tetracycline, flurbiprofen or PDGF-BB loaded membrane was markedly effective for osteoid tissue and new bone formation in the bony defect prepared in rat calvaria to compare with that by unloaded membrane. These results suggested that drug-loaded biodegradable barrier membrane might be a potential tool for GBR in periodontal therapy.

Vascular smooth muscle cell phenotype influences glycosaminoglycan composition and growth effects of extracellular matrix

Rat neonatal and neointimal vascular smooth muscle cells differ dramatically from adult medical vascular smooth muscle cells in their growth properties, with the neonatal and neointimal cells exhibiting growth in the absence of exogenously added growth factors. Since it has been hypothesized that extra-cellular matrix proteoglycans may influence the growth and differentiation of vascular smooth muscle cells, we examined the ability of matrix derived from these cells to influence vascular smooth muscle cell proliferation. To produce test matrices, cells were grown to confluence and removed by brief alkali treatment. Test cells were seeded onto these matrices and the rates of growth in a growth-factor-deficient medium determined. Compared to plastic wells, matrix from neonatal or neointimal cells stimulated the growth of vascular smooth muscle cells. Interestingly, matrix from adult cells was less efficient at promoting growth. Enzymatic digestion of extracellular matrix heparan sulfate, but not of other glycosaminoglycans, further increased the growth-stimulatory effect of extracellular matrix, suggesting that matrix heparan sulfate acts as a growth inhibitor. Consistent with this, biochemical analysis showed that the adult matrix contained a higher percentage of heparan sulfate compared with neonatal or neointimal matrix. These results suggest that autocrine production of heparan sulfate proteoglycans may play an important role in growth regulation of vascular smooth muscle cells during normal vascular development and differentiation as well as in pathological response to injury.

Antianaphylactic activity of Poncirus trifoliata fruit extract

The effect of an aqueous extract of Poncirus trifoliata (L.) Raf. (Rutaceae) fruits (PTFE) on compound 48/80-induced mortality associated with anaphylaxis was studied in rats. PTFE inhibited compound 48/80-induced anaphylaxis 100% with a dose of 1.6 mg/g body weight (BW) 1 h before or 5 min after injection of compound 48/80. PTFE inhibited compound 48/80-induced anaphylaxis almost 100% with doses above 0.4 mg/g BW intraperitoneally administered. PTFE (1-1000 micrograms/ml) also dose-dependently inhibited the histamine release induced by compound 48/80 (5 micrograms/ml) in rat peritoneal mast cells. The level of cAMP in peritoneal mast cells, when PTFE was added, increased transiently, and significantly increased 53-fold at 10 s compared with that of basal cells. Moreover, PTFE inhibited intracellular calcium release induced by compound 48/80. These results suggest that PTFE has antianaphylactic activity by stabilizing the peritoneal mast cell membrane.

Effect of 13-cis-retinoic acid with neoadjuvant chemotherapy in patients with squamous cervical carcinoma

Retinoids are strong inhibitors of epithelial cancer promotion and progression in experimental carcinogenesis. Recently, therapeutic trials of retinoids have demonstrated activities in cervical cancer and precancerous lesion of cervix. Our purpose was to determine whether additional administration of 13-cis-retinoic acid would improve the treatment effect of neoadjuvant chemotherapy in patients with squamous cell carcinoma of the cervix. From January 1994 through January 1995, 40 patients with invasive cervical cancer were enrolled in this prospective study and randomized into the two groups. Group 1 had neoadjuvant chemotherapy alone and group 2 had neoadjuvant chemotherapy plus 13-cis-retinoic acid (RA) at a dosage of 1 mg/kg/day for 1 month. Patients in group 1 and group 2 were similar with respect to age, parity, clinical stage, and histological subtype. Therapeutic responses were compared using Fisher's exact test, Mann-Whitney test, and Wilcoxon signed-rank test. RA increased the complete response rate of neoadjuvant chemotherapy from 0% in group 1 to 5% in group 2. However, a difference of overall clinical response rate between the two groups was not evident. The drug toxicities in group 1 and group 2 included anemia in 30.0% and 23.7%, leukopenia in 6.7% and 15.2%, and hepatotoxicity in 6.7% and 6.8%, respectively. More frequent incidence of mucocutaneous side effects was seen in group 2 than group 1, but these side effects were mild and reversible. The clinical response rate achieved in this trial indicates that the combination of 13-cis-retinoic acid and neoadjuvant chemotherapy, at least when used on the schedule reported herein, is not superior to treatment of neoadjuvant chemotherapy alone for patients with squamous cell carcinoma of the cervix. However, a single patient achieved a complete response on this therapy, and the impact of such a treatment on survival needs to be explored.

Hydrocephalus secondary to diffuse villous hyperplasia of the choroid plexus. Case report and review of the literature

Diffuse villous hyperplasia of the choroid plexus, which is distinct from bilateral choroid plexus papillomas, is extremely rare and is often associated with hydrocephalus due to the overproduction of cerebrospinal fluid (CSF). The authors describe an infant with hydrocephalus, diagnosed by computerized tomography scanning, who developed ascites following placement of a ventriculoperitoneal shunt and, subsequently, demonstrated excessive CSF production when the shunt was externalized. The patient was later successfully treated by placement of a ventriculoatrial shunt. Magnetic resonance imaging demonstrated diffuse villous hyperplasia of the choroid plexus as the cause of the patient's hydrocephalus. The literature on diffuse villous hyperplasia of the choroid plexus is reviewed.

Meningiomas in the region of the cavernous sinus: a review of 21 patients

This is a review of 21 patients with meningiomas involving the region of the cavernous sinus. All underwent surgery, and the fronto-zygomatic (F-Z) approach, first described by Fujitsu and Kubawara, was employed in every case. The mean age at presentation was 47 years; seven patients were male and 14 female. The mean duration of symptoms before surgery was 4 years. In 10 patients, resection was considered to be complete. Peri-operatively there were two deaths, but the majority of deficits in the survivors were temporary and quickly resolved. The mean follow-up period was 48 months. In that time, five patients experienced recurrence or progression of tumour, of whom three required repeat operation (followed by radiotherapy); and two patients were referred for radiotherapy alone. These five patients appear to be disease-free 2-5 years after their additional treatment. Of the 19 patients who left hospital, 17 were able to live independent lives. It would appear from this review that: (1) F-Z craniotomy usually gives excellent exposure to the region of the cavernous sinus; (2) selected patients should undergo angiography with balloon occlusion to evaluate the collateral vascular supply; (3) regular review should include annual MRI. Evaluation over a much longer time of both surgery and radiotherapy, individually and in combination, is needed before it will be possible to furnish a treatment protocol for individual cases at initial presentation or recurrence.

Mammary excretion and placental transfer of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane] platinum(II) in rats

The mammary excretion and placental transfer of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolan e] platinum(II) (CAS 146665-77-2, SKI 2053R), a new potential anticancer agent, were investigated in the lactating or pregnant rats after a single intravenous administration of 14C-SKI 2053R (20 mg/kg, 100 microCi/kg). The radioactivity of the milk declined in a biexponential fashion with an initial half-life of 0.39 h and with a terminal half-life of 14.05 h in the lactating rats. The radioactivity of the milk was lower than that of plasma until 1 h after dosing, but was higher than that of plasma from 4 h after dosing. 14C-SKI 2053R was well distributed to most tissues including uterus and placenta in the pregnant rats, but the levels of radioactivity in the amniotic fluid and fetuses were markedly lower than that in the maternal plasma. Therefore, it is concluded that SKI 2053R scarcely passes the blood-placenta barrier, which was confirmed by the whole-body autoradiography study.

Isoform-specific interaction of the alpha1A subunits of brain Ca2+ channels with the presynaptic proteins syntaxin and SNAP-25

Presynaptic Ca2+ channels are crucial elements in neuronal excitation-secretion coupling. In addition to mediating Ca2+ entry to initiate transmitter release, they are thought to interact directly with proteins of the synaptic vesicle docking/fusion machinery. Here we report isoform-specific, stoichiometric interaction of the BI and rbA isoforms of the alpha1A subunit of P/Q-type Ca2+ channels with the presynaptic membrane proteins syntaxin and SNAP-25 in vitro and in rat brain membranes. The BI isoform binds to both proteins, while only interaction with SNAP-25 can be detected in vitro for the rbA isoform. The synaptic protein interaction ("synprint") site involves two adjacent segments of the intracellular loop connecting domains II and III between amino acid residues 722 and 1036 of the BI sequence. This interaction is competitively blocked by the corresponding region of the N-type Ca2+ channel, indicating that these two channels bind to overlapping regions of syntaxin and SNAP-25. Our results provide a molecular basis for a physical link between Ca2+ influx into nerve terminals and subsequent exocytosis of neurotransmitters at synapses that have presynaptic Ca2+ channels containing alpha1A subunits.

Role of the 70-kDa subunit of human replication protein A (I). Single-stranded dna binding activity, but not polymerase stimulatory activity, is required for DNA replication

Replication protein A (RPA), also known as human single-stranded DNA-binding protein, is a three-subunit protein complex with multiple functions. Here, we investigated the role of the 70-kDa RPA subunit (p70) in DNA replication, by generating a series of deletion mutants. Mutant p70, which lacked 50 amino acids at the C-terminus, failed to interact with the 11-kDa RPA subunit (p11) and, when deleted further at the C terminus, was unable to interact with either the 34-kDa subunit (p34) or with p11, suggesting that p70 directly interacts with both p34 and p11. Studies with purified RPA mutants indicated that deletions at the N-terminal domain of p70 had very little effect on RPA's single-stranded DNA (ssDNA) binding activity, whereas deletion of amino acids 169-246 significantly weakened the DNA binding ability of RPA. By deleting amino acids 296-373 or 374-458, we totally abolished p70's ssDNA binding activity, suggesting that multiple p70 domains are involved in DNA binding. Two p70 domains, the N-terminal domain and the DNA binding domain, were required to stimulate DNA polymerase (pol) alpha, yet the DNA binding domain alone supported pol delta activity. Interestingly, RPA containing p70 with a zinc-finger domain deletion retained its DNA binding activity, but inhibited pol alpha and delta activity. RPA that lacked ssDNA binding activity failed to support simian virus 40 (SV40) DNA replication in vitro, whereas mutant RPA that lacked pol alpha stimulatory activity (including the zinc-finger p70 mutant) functioned normally. We conclude that RPA's DNA binding activity, but not its pol alpha stimulatory activity, is required for DNA replication.

Pharmacokinetics of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1, 3-dioxolane]platinum(II) in rats

The blood concentration-time profile, distribution, and excretion of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1, 3-dioxolane]platinum(II) (CAS 146665-77-2, SKI 2053R), a new potential anticancer agent, were investigated in rats after intravenous administration of 14C-SKI 2053R. After a single intravenous administration, the radioactivity of blood declined in a biexponential fashion with the initial half-lives of 0.42 h and 0.37 h and with the terminal half-lives of 68.67 h and 64.67 h in male and female rats, respectively. Radioactivity was distributed very rapidly and extensively into all tissues except the central nervous system. The major amount of the radioactivity was found in the gastrointestinal contents, urine, and organs of elimination at all time points. The distribution pattern of 14C-SKI 2053R observed by the measurement of tissue concentrations was in accordance with that observed by whole-body autoradiography. The 0-7 days cumulative urinary and fecal recoveries of total radioactivity after a single dose were 83.0 +/- 4.5 (mean +/- S.D.) and 11.3 +/- 1.0% in male rats and 85.1 +/- 2.6 and 11.3 +/- 2.3% in female rats, respectively, resulting in total recoveries of 94.3 +/- 3.6% in male rats and 96.3 +/- 1.1% in female rats. The 0-24 h cumulative excretions of total radioactivity in the bile after a single dose were 8.7 +/- 0.4 and 15.8 +/- 3.5% in male and female rats, respectively, showing a significant sex difference.

Pharmacokinetics of a new platinum compound, cis-(glycolato-O,O) [(4R,5R)-4,5-bis(aminomethyl)-1,3-dioxolane-2-spiro-1'-cyclohexane]plat inum (II) in dogs

A pharmacokinetic study on cis-(glycolato-O,O)/ (4R,5R)-4,5-bis(aminomethyl)-1,3-dioxolane-2-spiro-1'- cyclohexane]platinum(II) (SKI 2032R) was performed in dogs. A single dose of 2.0 mg/kg of SKI 2032R was administered i.v. bolus to three beagle dogs. Plasma samples were analyzed for platinum by flameless atomic absorption spectrophotometry. Plasma concentrations of total and ultrafiltrable platinum for SKI 2032R declined in a biexponential fashion. The mean area under the concentration-time curve (AUC0 --> infinity) determined for ultrafiltrable platinum derived from SKI 2032R, as an active component, was 2.36 +/- 0.23 micrograms. h/ml (mean +/- S.D.), with an initial half-life of 0.23 +/- 0.20 hour, a terminal half-life of 1.32 +/- 0.49 hour, a total clearance of 14.17 +/- 1.50 ml/min/kg, and a steady-state volume of distribution of 1.21 +/- 0.24 l/kg.

Preoperative endovascular embolization of craniospinal hemangioblastomas

PURPOSE

To determine whether hemangioblastomas, highly vascular tumors requiring surgery that is potentially complicated by excessive bleeding, can be embolized safely by using interventional techniques that furnish a more avascular surgical field.

METHODS

Nine hemangioblastomas involving either the cerebellum or the spinal cord were embolized preoperatively. In each case the feeding artery was selectively catheterized with a microcatheter and the hypervascular tumor nidus was devascularized with polyvinyl alcohol particles.

RESULTS

Two patients who had undergone recent attempts as surgical resection at another institution had repeat surgery after endovascular embolization rendered the tumor nidus avascular. At surgery, the tumor was completely removed in one case and markedly debulked in the other. In all nine cases, blood loss after embolization was reported to be less than expected by experienced surgeons. In addition, manipulation and removal of the tumor was reported to be subjectively easier in these embolized tumors. The embolization procedure caused no permanent complications; however, one patient with a posterior fossa hemangioblastoma and hydrocephalus worsened clinically within 12 hours of embolization. This event was thought to be caused by obstructive hydrocephalus resulting from tumor swelling. Emergency craniotomy, ventricular decompression, and surgical resection of the tumor produced complete resolution of the signs and symptoms.

CONCLUSIONS

Our results indicate that preoperative embolization of hemangioblastomas is a safe procedure that is useful in aiding surgical resection of these highly vascular tumors.

Expression of epidermal growth factor receptor in carcinoma of the cervix

Increased expression of the epidermal growth factor receptor (EGFR) gene has been shown in a large number of tumors, generally indicating a more aggressive biological behavior of cancers than those with low or normal expression. The role of EGFR in the tumorigenesis of the uterine cervix has been poorly understood and controversial. In order to explore the relationship between EGFR status and cervical carcinoma, tissues were analyzed from 40 patients, each of whom had invasive cervical carcinoma prior to treatment, 20 patients with cervical intraepithelial neoplasia (CIN) and 10 control cases who underwent hysterectomy due to benign gynecological disease at Yonsei University College of Medicine. We measured EGFR with an enzyme-linked immunosorbent assay which was a sandwich type using a mouse monoclonal capture antibody and a rabbit antiserum as detector. Patients with invasive cervical cancer were found to have significantly higher median EGFR expression than either the patients with CIN (P = 0.002) or the control (P = 0.001), respectively. However, there was no significant difference in EGFR status between CIN and the control groups. Overexpression of EGFR was found in 29 of 40 (72.5%) invasive cervical cancers and in 5 of 20 (25%) CIN patients. In invasive cervical cancer, no significant difference in EGFR levels was noted when stratified according to age, menopausal status, histological cell type, or clinical stage. With regard to tumor size, lesions of 4 cm and larger had significantly higher receptor levels than those lesions under 4 cm (P = 0.003). Even though quantitative EGFR status did not correlate with other prognostic parameters except tumor size, our results were consistent with the concept that EGFR may play an important role in malignant transformation and tumorigenesis in cervical cancer.

Fibroepithelial ureteral polyp--a case report; endoscopic removal of large ureteral polyp

We report a case of primary fibroepithelial polyp of the right midureter. The patient was a 41-year-old-woman, complaining of right flank pain. An excretory urogram revealed right hydronephrosis and a filling defect of the the right midureter. The filling defect was produced by a large fibroepithelial polyp that was diagnosed and removed by ureteroscopy without open surgery. Large fibroepithelial ureteral polyps are relatively rare and ureteroscopy is the gold standard of diagnosis for ureteral filling defect.

In vitro cytotoxicity, pharmacokinetics and ex vivo pharmacodynamics of a new platinum compound, cis-malonato [(4R,5R-4,5-bis(aminomethyl)-1,3-dioxolane-2-spiro-1'-cyclopentane] platinum (II)

The in vitro cytotoxicity of a new platinum complex, cis-malonato [(4R, 5R)-4,5-bis(aminomethyl)-1,3-dioxolane 2- spiro 1' cyclo-pentane]platinum(II) (SKI 2054R) and cisplatin (CDDP) was evaluated against two human stomach adenocarcinoma cell lines (MKN-45 and KATO III) and a human lung adenocarcinoma cell line (PC-14). The in vitro 50% inhibitory concentration (IC50) values of SKI 2054R and CDDP against MKN-45, KATO III, and PC-14 were 1.21 and 0.51, 2.11 and 0.83, and 2.90 and 0.77 micrograms/ml, respectively. The pharma-cokinetic and ex vivo pharmacodynamic studies on SKI 2054R and CDDP were performed in beagle dogs. Equitoxic doses of SKI 2054R and CDDP (7.0 and 3.0 mg/kg, respectively) were administered i.v. bolus to beagle dose in a randomized crossover study. Plasma samples were analyzed for platinum by flameless atomic absorption spectrophotometry. Plasma concentrations of total and ultrafiltrable platinum for the two drugs declined in a biexponential fashion. The mean area under the concentration-tine curve (AUC(0)--> infinity) determined for ultrafiltrable platinum derived from SKI 2054R, as an active component was 6.61 +/- 2.34 micrograms . h/ml (mean +/- S.D.), with an initial half-life of 0.26 +/- 0.14 h, a terminal half-life of 1.57 +/- 0.71 hour, a total clearance of 17.65 +/- 4.99 ml/min/kg, and a steady-state volume of distribution of 1.46 +/- 0.11 l/kg. The ex vivo antitumor activity of SKI 2054R was assessed using the ultrafiltrable plasma against MKN-45, KATO III, and PC-14 by tetrazolium-dye (MTT) assay and was compared with that of CDDP using the antitumor index (ATI) determined from the ex vivo pharmacodynamic results of inhibition rates (%) versus time curves. The mean ATI value recorded for SKI 2054R was higher than that noted for CDDP; however, statistical difference was not observed between SKI 2054R and CDDP, suggesting that the antitumor activity of SKI 2054R is comparable to that of CDDP. These results suggest that SKI 2054R is a new platinum complex which is worth being evaluated further.

Pharmacokinetics, tissue distribution, and excretion of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3- dioxolane]platinum(II) in dogs

The pharmacokinetics, tissue distribution, and excretion of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3- dioxolane]platinum(II) (SKI 2053R), a new potential anticancer agent, were investigated in dogs after a single intravenous administration of [14C]SKI 2053R (7 mg/kg, 100 microCi/kg). Total radioactivity in the plasma and ultrafiltrable plasma declined in a biexponential fashion with the initial half-lives of 0.63 +/- 0.05 hr (mean +/- SD) and 0.53 +/- 0.05 hr, and with the terminal half-lives of 51.08 +/- 3.26 hr and 15.19 +/- 3.75 hr, respectively. Radioactivity was well distributed into all tissues except the central nervous system. The majority of the radioactivity was found in the gastrointestinal contents, urine, and organs of elimination at all time points. The distribution pattern of [14C]SKI 2053R in the whole-body autoradiograms was consistent with that observed by the measurement of tissue concentrations. The 0-7 days cumulative urinary and fecal recoveries of total radioactivity were 87.30 +/- 2.93% and 8.68 +/- 1.30%, respectively, resulting in a total recovery of 95.98 +/- 1.61% of the administered dose. A large portion of [14C]SKI 2053R was distributed into the cellular fraction of mouse or rat blood, but was not into that of dog or human blood in vitro. The in vitro and in vivo binding of [14C]SKI 2053R to plasma protein was minimal to moderate.

Antiviral activity of 9-[[(ethoxyhydroxyphosphinyl)-methoxy]methoxy] guanine against cytomegalovirus and herpes simplex virus

An isosteric analog of 9-[2-(phosphonomethoxy)ethyl]guanine (PMEG), 9-[[(ethoxyhydroxyphosphinyl)methoxy]methoxy]guanine (SKI 1008), was evaluated for its in vitro antiviral activity against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), murine cytomegalovirus (MCMV), and human cytomegalovirus (HCMV), and its in vivo antiviral efficacy against MCMV in mice. The in vitro anti-HSV activity of SKI 1008 was much lower than that of acyclovir, even though SKI 1008 showed similar antiviral activity against thymidine kinase positive (TK+) and thymidine kinase negative (TK-) strains. Like ganciclovir and PMEG, SKI 1008 selectively inhibited plaque formation of MCMV; the 50% effective concentration (EC50) and the 50% cytotoxic concentration (CC50) of SKI 1008, ganciclovir, and PMEG being 0.51 and 600, 1.65 and 461, and 0.06 and 12.1 micrograms/ml, respectively. The in vitro EC50 value of SKI 1008 against HCMV was comparable to that of ganciclovir (0.24 vs 0.16 microgram/ml) and was 12-fold higher than that of PMEG in a plaque reduction assay, but the therapeutic indices (the ratios of CC50 to EC50) of SKI 1008 and ganciclovir were higher than that of PMEG. The in vivo antiviral efficacy of SKI 1008 in MCMV-infected normal BALB/c and severe combined immunodeficiency (SCID) mice was lower than that of ganciclovir in terms of mortality and mean survival time.

Beta 1 integrin expression in malignant melanoma predicts occult lymph node metastases

BACKGROUND

Elective lymph node dissection for malignant melanoma is still controversial. Experimental studies suggest that differential expression, activation, or both of beta1 integrins facilitate melanoma metastases. However, the clinical significance of beta1 integrin expression in human melanoma is unclear.

METHODS

We examined primary cutaneous melanomas from 76 patients undergoing elective lymph mode dissection. We quantified the percentage of tumor area stained by beta1 integrin antibody with an image analyzer.

RESULTS

beta1 integrin was expressed in all 23 primary tumors from patients with pathologically positive lymph nodes (LNs) but in only 14 (26%) of 53 cases with pathologically negative nodes (p < 0.001). No patients with beta1 integrin-negative tumors had LN involvement, whereas 23 (62%) of 37 patients with beta1 integrin-positive tumors had LN metastases (p < 0.001). Furthermore, 21 (91%) of 23 cases with LN metastases but only 4 (8%) of 53 cases without had beta1 integrin staining of 10% or more of tumor area (p < 0.001).

CONCLUSIONS

Our study is the first to show a correlation between expression of a molecular marker in the primary cutaneous melanoma and likelihood of regional LN metastases. beta1 immunostaining of 10% or more of tumor area reliably predicts patients most likely to harbor occult LN metastases and likely to benefit from ELND.

Human xeroderma pigmentosum group A protein interacts with human replication protein A and inhibits DNA replication

Human replication protein A (RPA; also known as human single-stranded DNA binding protein, or HSSB) is a multisubunit complex involved in both DNA replication and repair. While the role of RPA in replication has been well studied, its function in repair is less clear, although it is known to be involved in the early stages of the repair process. We found that RPA interacts with xeroderma pigmentosum group A complementing protein (XPAC), a protein that specifically recognizes UV-damaged DNA. We examined the effect of this XPAC-RPA interaction on in vitro simian virus 40 (SV40) DNA replication catalyzed by the monopolymerase system. XPAC inhibited SV40 DNA replication in vitro, and this inhibition was reversed by the addition of RPA but not by the addition of DNA polymerase alpha-primase complex, SV40 large tumor antigen, or topoisomerase I. This inhibition did not result from an interaction between XPAC and single-stranded DNA (ssDNA), or from competition between RPA and XPAC for DNA binding, because XPAC does not show any ssDNA binding activity and, in fact, stimulates RPA's ssDNA binding activity. Furthermore, XPAC inhibited DNA polymerase alpha activity in the presence of RPA but not in RPA's absence. These results suggest that the inhibitory effect of XPAC on DNA replication probably occurs through its interaction with RPA.

Glutamate stably enhances the activity of two cytosolic forms of phospholipase A2 in brain cortical cultures

The mechanisms by which glutamatergic neurotransmitters modulate neuronal lipid metabolism are not well established. We have directly measured phospholipase A2 (PLA2) enzymic activity in cell-free extracts from cortical neuronal cultures from rat brain and have found that the PLA2 activity is up-regulated after cells are exposed to glutamate. Brief exposure to a calcium ionophore or phorbol 12-myristate 13-acetate (PMA) stably enhanced PLA2 activity. Down-regulation of protein kinase C activity partially blocked glutamate's effects. Two Ca(2+)-and pH-dependent forms of PLA2 were identified in cytosolic extracts. Activation of both forms of PLA2 was enhanced by prior exposure of the cultures to glutamate. One of the two forms had chromatographic characteristics on heparin-Sepharose, Mono Q and Superose 12 columns similar to the 100 kDa cytosolic PLA2 (cPLA2), and was recognized by an antibody raised to pig spleen cPLA2. The second form was similar in size to Group-I and -II PLA2s but differed in chromatographic characteristics. It was not inhibited by dithiothreitol, and did not react with antibodies to pancreatic Group-I PLA2, features that distinguish it from Group-I and -II PLA2. In extracts from cells pretreated with glutamate, the activity-Ca2+ concentration dose-response relationship of the 13.5 kDa form of PLA2 was shifted to the left with activation at lower Ca2+ concentration as the result of stable modification of the enzyme induced by glutamate. Thus glutamate-induced stable enhancement of PLA2 activity, by processes involving calcium and protein kinase C activation, is a potential molecular switch probably mediating changes in synaptic function and contributing to excitotoxicity.