The causes of and cures for contact lens-induced peripheral ulcer

PURPOSE

Contact lens-induced peripheral ulceration (CLPU) is a relatively common adverse response associated with wearing hydrogel lenses, especially on an extended wear schedule. Bacteriologic examination of lenses at the time of an event has demonstrated an association with Staphylococci spp. We sought to investigate the causes of CLPU in a rabbit model of contact lens wear.

METHODS

Rabbits wore contact lenses for a period of 24 hr in the presence or absence of bacteria or in presence or absence of epithelial scratches made in the periphery of the cornea before lens wear. Bacteria tested were a strain of Staphylococcus aureus or a strain of Staphylococcus epidermidis isolated from human CLPUs. Rabbits were also challenged with S. aureus in the presence of an epithelial defect and in the absence of a contact lens. Corneas were monitored by slitlamp, histology, and microbial culture after 24 hr.

RESULTS

No CLPU-like lesions were detected under the following conditions: corneal scratch plus lens wear with no bacteria; corneal scratch plus S. epidermidis colonized lenses; corneal scratch without lens wear and with S. aureus applied to eyes; no scratch plus S. aureus colonized lenses; and corneal scratch plus contact lenses colonized by dead S. aureus. CLPU-like lesions were found only when the corneas were scratched and contact lenses colonized by viable S. aureus were applied to the eye. The histology of the lesions demonstrated a frank epithelial break with underlying stromal infiltration. Only low numbers of bacteria could be cultivated from the corneas with CLPU-like lesions. The CLPU-like lesions shared many similarities with CLPU in humans.

CONCLUSION

CLPU-like lesions were only produced by S. aureus and not S. epidermidis in the presence of an epithelial abrasion and contact lens. Thus, we hypothesize that to reduce the incidence of CLPU, contact lenses designed to reduce corneal interaction and repel microbial colonization should be produced.

[Molecular genetic marker identification of traditional Chinese drug hippocampus]

Ancient DNA technique was used to extract DNA from 5 species of Chinese traditional drugs Hippocampus. The 12S rRNA gene fragment and cytochrome b gene fragment were amplified from DNA extract using Polymerase Chain Reaction (PCR) method. Restriction Fragment Length Polymorphism (RFLP) analysis and DNA sequence analysis were performed. The RFLP analysis method can identify 2 species of Hippocampus. The molecular genetic markers produced by DNA sequence method can identify all 5 species of Hippocampus. This method will be valuable for the identification of other animal drugs.

An intelligent sales forecasting system through integration of artificial neural networks and fuzzy neural networks with fuzzy weight elimination

Sales forecasting plays a very prominent role in business strategy. Numerous investigations addressing this problem have generally employed statistical methods, such as regression or autoregressive and moving average (ARMA). However, sales forecasting is very complicated owing to influence by internal and external environments. Recently, artificial neural networks (ANNs) have also been applied in sales forecasting since their promising performances in the areas of control and pattern recognition. However, further improvement is still necessary since unique circumstances, e.g. promotion, cause a sudden change in the sales pattern. Thus, this study utilizes a proposed fuzzy neural network (FNN), which is able to eliminate the unimportant weights, for the sake of learning fuzzy IF-THEN rules obtained from the marketing experts with respect to promotion. The result from FNN is further integrated with the time series data through an ANN. Both the simulated and real-world problem results show that FNN with weight elimination can have lower training error compared with the regular FNN. Besides, real-world problem results also indicate that the proposed estimation system outperforms the conventional statistical method and single ANN in accuracy.

Developmental behavior of gene expression for brown rice thickness under different environments

The dynamic changes of genetic effects, including main effects, and genotype x environment (GE) interaction effects on brown rice thickness (BRT) across environments were investigated by using the developmental genetic models. Seven cytoplasmic male sterile lines of indica rice (Oryza sativa L.) as females and five restoring lines as males were used in a factorial design to produce grains of F(1)s and F(2)s in two environments (years) for developmental genetic analysis. The results indicate that genetic effects, especially GE interaction effects of triploid endosperm genes, cytoplasm genes, and diploid maternal plant genes were important to the performance of BRT at various filling stages of rice. The BRT was genetically controlled by the net genetic effects of genes expressed at the early and late filling stages (1-7 days and 15-21 days after flowering, respectively). The differences in net genetic effects under different environments for endosperm, cytoplasm, and maternal plant genes were found, and the net GE interaction effects were more important to BRT at the early filling and mature stages of rice. Some net genetic effects, especially for net cytoplasm effects spasmodically expressed, were detected among filling stages. Higher additive and cytoplasm main effects, along with their interaction effects, were found, which would be useful for selection for BRT in breeding programs. The predicated genetic effects at different filling stages show that the parents of V20 and Xieqingzao were better than others for improving BRT of progenies.

[Molecular identification of the Chinese drug turtle shells]

This paper reports a new method to identify the Chinese drug turtle shells using PCR product direct sequencing method. DNA was extracted from tissues of the Chinese three-keeled pond turtle Chinemys reevesii and 20 other species of turtles occurring in China and Southeast Asian countries. One hundred and ten base pairs of mitochondrial 12S rRNA gene fragment were amplified from the extract using PCR technique and obtained sequences. These sequences were used to construct 12S rRNA gene fragment sequence database for the 21 turtle species. Comparison of these sequences indicated that the sequence from the Chinese three-keeled pond turtle is different from that of all the other 20 turtle species. The sequence divergence is 3.7-15.7%. DNA was extracted from 0.1-0.5 g of shell from 19 turtle shells provided by the Jiangsu Institute for Drug Control and 12S rRNA gene fragment was amplified and sequenced. Comparison of the sequences from the 19 turtle shells and 12S rRNA gene fragment sequence database indicated that only 3 samples are shells of the Chinese three-keeled pond turtle specified in the Phamacopoeia of the People's Republic of China and the others are substitutes. The technique used in the present paper was found to be effective and reliable for the identification of turtle shells.

Effects of long-term enalapril and losartan therapy of heart failure on cardiovascular aldosterone

Plasma aldosterone escape is found during long-term ACE inhibitor therapy of chronic heart failure. Evidence for aldosterone production in cardiovascular tissues raised the question of whether aldosterone escape occurs or not in these tissues. Rats with infarction-induced chronic heart failure were treated with enalapril (20 mg/kg/d) and losartan (15 mg/kg/d) for 20 weeks. Untreated chronic heart failure and sham-operated rats were used as positive and normal controls, respectively. Ex vivo mesenteric artery and heart perfusion, high performance liquid chromatography, and RIA for aldosterone were performed. Chronic heart failure due to myocardial infarction was associated with tissue-specific activation of cardiovascular aldosterone synthesis. In the mesenteric artery, enalapril significantly inhibited aldosterone production compared to untreated, chronic heart failure rats, and losartan lowered aldosterone production to that of sham rats. In myocardium, enalapril failed to significantly inhibit aldosterone production, and losartan significantly inhibited aldosterone production compared to untreated, chronic heart failure rats. These results provide the first evidence that long-term ACE inhibition therapy induces aldosterone escape in myocardium but not in mesenteric artery of chronic heart failure. The angiotensin II subtype 1 receptor blocker losartan tranquilized aldosterone levels in the cardiovascular tissues of chronic heart failure rats.

Effects of long-term enalapril and losartan therapy of hypertension on cardiovascular aldosterone

BACKGROUND

Plasma aldosterone escape is found during long-term angiotensin-converting enzyme inhibitor therapy. Evidence for aldosterone production in cardiovascular tissues raised the question of whether or not aldosterone escape occurs in these tissues.

METHOD

Spontaneously hypertensive rats were treated with enalapril (20 mg/kg/day) and losartan (50 mg/kg/day) for 20 weeks; untreated spontaneously hypertensive and Wistar rats were used as positive and normal controls, respectively. Ex vivo mesenteric artery and heart perfusion, high-performance liquid chromatography, and radioimmunoassay for aldosterone were performed.

RESULTS

The results showed that enalapril failed to significantly inhibit aldosterone production in mesenteric artery, myocardium and plasma. Losartan significantly inhibited aldosterone production to that of Wistar rats in the mesenteric artery, myocardium and plasma.

CONCLUSION

This study provides the first evidence that long-term angiotensin-converting enzyme inhibition therapy induces aldosterone escape in hypertensive cardiovascular tissues, and angiotensin II subtype 1 receptor antagonist does not induce aldosterone escape in mesenteric artery, myocardium and plasma of spontaneously hypertensive rats.

Transduction of human neural progenitor cells using recombinant adeno-associated viral vectors

Human neural progenitor cells (hNPCs) represent an attractive source for cell therapy of neurological disorders. Genetic modification of hNPCs may allow a controlled release of therapeutic proteins, suppress immune rejection, or produce essential neurotransmitters. In search of an effective gene delivery vehicle, we evaluated the efficiency of a recombinant adeno-associated viral (rAAV) vector expressing enhanced green fluorescent protein (CAGegfp). Our study demonstrated that CAGegfp efficiently transduced both proliferating and differentiated hNPCs in vitro. EGFP expression was detected as early as 1 day after exposure to CAGegfp and was detectable for up to 4 months. Following transduction, the growth rate of hNPCs slowed down, but they were still able to differentiate into neurons and glia. Furthermore, CAGegfp-modified hNPCs survived, differentiated and expressed EGFP after transplanting into spinal cord of adult rats. Our results indicated that rAAV vectors might be a useful tool in hNPC-based cell and gene therapy for neurological disorders.

Human phosphodiesterase 8A splice variants: cloning, gene organization, and tissue distribution

We have cloned cDNAs representing five full-length human phosphodiesterase (PDE) 8A splice variants (PDE8As 1-5) from testis and T cells. PDE8A1 encodes a hydrophilic protein of 829 amino acids, containing an N-terminal REC domain, a PAS domain, and a C-terminal catalytic domain. PDE8A2 encodes a protein of 783 amino acids, identical to PDE8A1 but lacking the PAS domain. PDE8A3 encodes a shorter protein equivalent to the C-terminal 449 amino acids of PDE8A1, containing the catalytic but not the REC and PAS domains. PDE8A4 and PDE8A5, though different from each other at the nucleotide level, encode an identical protein equivalent to the C-terminal 582 amino acids of PDE8A1, including half of the PAS domain. The PDE8A gene is revealed to contain 23 exons, and its exon-intron boundaries have been defined. In addition, we have mapped a common transcription initiation site, and further determined the upstream 5'-flanking sequence of 1740 bp containing the putative promoter. Compared to PDE8A1, PDE8As 2-5 appear to be expressed in much lower abundance. Among various tissues and organs, PDE8A1 and PDE8A2 are expressed at various levels.

Mechanism of action of the des-F(6) quinolone BMS-284756 measured by supercoiling inhibition and cleavable complex assays

BMS-284756 (T-3811ME), a novel des-F(6) quinolone, was tested in the supercoiling inhibition and cleavable complex assays against Escherichia coli DNA gyrase, a target of quinolones. The results suggest that BMS-284756 has the same mechanism of action against DNA gyrase as other quinolones and a similar level of potency.

Association between allergy and anxiety disorders in youth

OBJECTIVE

Studies have documented associations between anxiety disorders and allergy in adults, but these associations have not been studied extensively in children. The objective of this study is to examine the associations between allergy and six anxiety disorders (AD) in youth.

METHOD

This is a data analysis of two epidemiologic-services studies: (i) alternative service use patterns of youth with serious emotional disturbance (n = 936), and (ii) methods for the epidemiology of child and adolescent mental disorders (n = 1285). Child psychiatric diagnoses were measured by the diagnostic interview schedule for children. Allergy was assessed by the service utilization and risk factors interview.

RESULTS

Among ADs, the strongest association found was between allergy and panic disorder (adjusted odds ratio 5.0; p < or = 0.001). Associations of allergy and the other ADs do not seem to be clinically significant.

CONCLUSIONS

Findings suggest that in some patients panic disorder may be associated with hypersensitivity of immune system. Panic disorder should be considered in anxious children reporting allergy when no organic cause of allergy is found, and likewise allergy should considered in children with panic disorder.

Identification of protein kinases dysregulated in CD4(+) T cells in pathogenic versus apathogenic simian immunodeficiency virus infection

Human immunodeficiency virus infection in humans and simian immunodeficiency virus (SIV) infection in rhesus macaques (RM) leads to a generalized loss of immune responses involving perturbations in T-cell receptor (TCR) signaling. In contrast, naturally SIV-infected sooty mangabeys (SM) remain asymptomatic and retain immune responses despite relatively high viral loads. However, SIV infection in both RM and SM led to similar decreases in TCR-induced Lck phosphorylation. In this study, a protein tyrosine kinase (PTK) differential display method was utilized to characterize the effects of in vivo SIV infection on key signaling molecules of the CD4(+) T-cell signaling pathways. The CD4(+) T cells from SIV-infected RM, but not SIV-infected SM, showed chronic downregulation of baseline expression of MLK3, PRK, and GSK3, and symptomatically SIV-infected RM showed similar downregulation of MKK3. In vitro TCR stimulation with or without CD28 costimulation of CD4(+) T cells did not lead to the enhancement of gene transcription of these PTKs. While the CD4(+) T cells from SIV-infected RM showed a significant increase of the baseline and anti-TCR-mediated ROR2 transcription, SIV infection in SM led to substantially decreased anti-TCR-stimulated ROR2 transcription. TCR stimulation of CD4(+) T cells from SIV-infected RM (but not SIV-infected SM) led to the repression of CaMKKbeta and the induction of gene transcription of MLK2. Studies of the function of these molecules in T-cell signaling may lead to the identification of potential targets for specific intervention, leading to the restoration of T-cell responses.

Human skeletal muscle PDH kinase activity and isoform expression during a 3-day high-fat/low-carbohydrate diet

The increase in skeletal muscle pyruvate dehydrogenase kinase (PDK) activity was measured in skeletal muscle of six healthy males after a eucaloric high-fat/low-carbohydrate (HF/LC; 5% carbohydrate, 73% fat, and 22% protein of total energy intake) diet compared with a standardized prediet (50% carbohdyrate, 30% fat, and 21% protein). Biopsies were obtained from the vastus lateralis muscle after 3 days on the prediet (day 0) and after 1, 2, and 3 days of the HF/LC diet. Intact mitchondria were extracted from fresh muscle and analyzed for PDK activity and Western blotting of PDK2 and PDK4 protein. A second biopsy was taken at each time point and frozen for Northern blot analysis of PDK2 and PDK4 mRNAs. PDK activity increased in a linear fashion over the 3-day HF/LC diet and was significantly higher than control by 1 day. PDK activity was 0.09 +/- 0.03, 0.18 +/- 0.05, 0.30 +/- 0.07, and 0.37 +/- 0.09 min(-1) at 0, 1, 2, and 3 days, respectively. PDK4 protein and mRNA increased maximally by day 1, and PDK2 protein and mRNA were unaffected by the HF/LC diet. Resting respiratory exchange ratios decreased after 1 day of the HF/LC diet (from 0.79 +/- 0.02 to 0.72 +/- 0.02) and remained depressed throughout the 3-day dietary intervention (0.68 +/- 0.01). The immediate shift to fat utilization was accompanied by increased blood glycerol, beta-hydroxybutyrate, and plasma free fatty acid concentrations. These results suggest that the continuing increase in PDK activity over the 3-day HF/LC diet is not due to increasing PDK protein beyond 1 day. This could be due to the contribution of another isoform to the total PDK activity or to a continual increase in PDK4 or PDK2 specific activity.

Hypoxia down-regulates endostatin production by human microvascular endothelial cells and pericytes

Endostatin is a potent anti-angiogenic factor derived from the C-terminal region of collagen XVIII and is implicated in the regulation of physiological and pathological angiogenesis. In this study, reverse transcription-polymerase chain reaction analysis of poly(A+) RNA demonstrated the presence of mRNA for collagen XVIII in human endothelial cells (EC) and pericytes, the very constituents of microvessels wherein angiogenesis takes place. Enzyme immunoassay revealed that both cell types liberated endostatin into culture media and that the endostatin levels were decreased by hypoxia, the principal cause of angiogenesis. Northern and Western blot analyses revealed that while the collagen XVIII/endostatin mRNA levels were invariant between hypoxic and normoxic conditions, the collagen XVIII protein levels in EC and pericytes decreased by hypoxia. Further, exogenously administered intact endostatin was significantly decreased when it was incubated with hypoxic conditioned media of endothelial cells or pericytes, but not with normoxic media. The results suggest that the reduction of autocrine endostatin may take an active part in hypoxia-driven angiogenesis.

Elevated interleukin-13 in patients with active lupus nephritis

OBJECTIVE

To investigate the significance of interleukin-13 (IL-13) in patients with active lupus nephritis (LN).

METHODS

Ten healthy volunteers and 16 patients with active LN were included in this study. The protein level of IL-13 in plasma was examined by enzyme linked immunosorbent assay (ELISA), and gene expression of IL-13 in peripheral blood mononuclear cells (PBMCs) by reverse transcription polymerase chain reaction (RT-PCR). Expression of IL-13 mRNA in renal tissue was studied by in situ hybridization (ISH) techniques.

RESULTS

The level of IL-13 in plasma and the expression of IL-13 mRNA in PBMCs were significantly higher in LN patients than those in the controls (P < 0.001). Increased expression of IL-13 mRNA was detected in renal tissue of active LN patients compared to those in the controls (P < 0.001). Analysis of the linear correlation indicated that the level of IL-13 mRNA in the tubulointerstitial area in patients with active LN correlated with the concentration of serum creatinine (Scr), the glomerular activity index (GAI), the activity index of tubulointerstitium, and the level of serum C3 (P < 0.05 for each).

CONCLUSION

The elevation of IL-13 may play an important role in the molecular pathogenesis of active LN.

Adaptive increase in pyruvate dehydrogenase kinase 4 during starvation is mediated by peroxisome proliferator-activated receptor alpha

Pyruvate dehydrogenase kinase isoform 4 (PDK4) is upregulated by starvation in many tissues of the body during starvation. This causes inactivation of the pyruvate dehydrogenase complex which blocks pyruvate oxidation and conserves lactate and alanine for gluconeogenesis. Enhanced PDK4 expression may be caused by the increase in free fatty acids that occurs during starvation. Free fatty acids can activate peroxisome proliferator-activated receptor alpha (PPARalpha), and activation of PPARalpha can promote PDK4 expression. This model is supported by the findings reported here that WY-14,643, a synthetic PPARalpha activator, increases PDK4 expression in wild-type mice but not in PPARalpha-null mice. Starvation likewise increases the expression of PDK4 in tissues of wild-type mice but not in tissues of PPARalpha-null mice. These findings document the functional importance of PPARalpha for PDK4 expression during starvation and suggest an important role for elevated free fatty acids in the induction.

A dramatic improvement of epoxide selectivity of [Ti,Al]-beta by ion-exchange with quaternary ammonium salts

Ion-exchange of [Ti,Al]-beta with quaternary ammonium acetates greatly enhances the epoxide selectivity in the oxidation of alkenes with hydrogen peroxide; this is due to the selective poisoning of the acid sites without suppressing the oxidation activity of Ti sites.

CYP11B2 expression in rat liver and the effect of spironolactone on hepatic fibrogenesis

OBJECTIVE

In consideration of the hypothetical possibility that locally produced aldosterone is likely to take an active part in fibrogenesis of the liver, we undertook the present study to investigate the expression of aldosterone synthase gene CYP11B2 in rat liver and the curative effect of spironolactone on fibrosis of the liver.

METHODS AND MATERIALS

160 Wistar rats weighing about 250 g were divided into four groups as follows: model group, spironolactone group, malotilate group and control group. After 2, 4, 6, 8 and 10 weeks, the animals were sacrificed. Morphological examination was based on microscopic and electron microscopic findings. The area of collagen was examined by an Image Analyse System (Leica). By means of reverse transcriptase-polymerase chain reaction and in situ hybridization, the expression of CYP11B2 was detected.

RESULTS

The expression of CYP11B2 mRNA, which was localized in the endoplasm of fat-storing cells, was upregulated when fibrogenesis occurred. The grade of fibrosis and the area of collagen in the spironolactone group were less than those in the model group before the 6th week (p < 0.05). After the 6th week, there was no significant difference between the spironolactone group and the model group (p > 0.05).

CONCLUSIONS

The expression of CYP11B2 mRNA is upregulated in fibrotic liver. Spironolactone can partly have a fibrogenesis-inhibiting effect in the early stage of CCl(4)-induced hepatic fibrogenesis.

Glycoproteins H and L of Marek's disease virus form a hetero-oligomer essential for translocation and cell surface expression

Glycoproteins H and L form a hetero-oligomeric complex (gH-L) which plays an important role in virus entry to host cells and cell-to-cell infection in herpesviruses. Interaction of gH and gL is considered to be critical for the biological function of these two glycoproteins. To investigate the interaction of MDV gH and gL, both gH and gL were expressed in in vitro cell culture systems using indirect immunofluorescence assay with gH and gL antibodies. The results suggested that co-expression of gH and gL in the same cells are required and necessary for both gH and gL subcellular translocation and cell surface expression. gL expressed in recombinant fowlpox virus (rFPV) infected chicken embryo fibroblasts (CEF) was consistently secreted into the culture medium. The primary peptide of gL binds with that of gH in the cytosol or ER lumen. By binding with gH, gL could anchor itself on the cell surface allowing for surface expression and viral spread to uninfected cells. The binding domain of gH was mapped to the amino acids 451-659 (SacI-HindIII) fragment and was essential for gH-L complex formation.

pH and cation effects on the properties of parallel pyrimidine motif DNA triplexes

The effects of cytosine protonation and various cations on the properties of parallel pyrimidine motif DNA triplexes were intensively investigated and characterized by several different techniques, such as circular dichroism (CD) conformation, ultraviolet (UV) melting, differential scanning calorimetry (DSC) thermal denaturation, and surface plasmon resonance (SPR) real-time dynamics. The comparative CD spectra of the triplex and the corresponding homoduplexes showed that the negative peak at approximately 218 nm would be the eigenpeak of the Hoogsteen paired strand, and moreover, the formation pathway of a triplex was significantly pH-dependent and fell into three groups: under acidic conditions, the triplex is formed by a one-step docking, under near physiological conditions, the Watson-Crick duplex is first structured and then accepts the Hoogsteen third strand into its major groove, and under basic conditions, the triplex is not formed. The pH-dependent thermodynamics of the global triplex, the Watson-Crick antiparallel duplex, and the Crick-Hoogsteen parallel duplex were comparatively discussed for the first time. These data revealed that the thermodynamic stabilities of the Watson-Crick-Hoogsteen triplex and the Crick-Hoogsteen duplex would be strongly dependent on cytosine protonation, but a low-pH environment somewhat destabilized the Watson-Crick duplex. The binding energy of triplex formation would be different from the unfolding energy of triplex melting under acidic conditions due to the disparity in the pathway between the formation and unfolding of a triplex. Real-time dynamic measurements showed that the association and dissociation rate constants of a duplex-to-triplex formation are (1.98 +/- 0.24) x 10(3) M(-1) s(-1) and (4.09 +/- 0.96) x 10(-4) s(-1) at 20 degrees C and pH 6.0, respectively. The formation energy of the duplex-to-triplex transition derived from SPR measurements was in agreement with the unfolding energy of the free Hoogsteen paired duplex derived from UV measurements. The calorimetric enthalpies of the triplex-to-duplex-to-single transition were 39.3 and 75.3 kcal/mol under near physiological conditions (pH 7.0), respectively, which were underestimated relative to the van't Hoff enthalpies. In addition, the effects of various cations, ionic strength, mixed-valent cations, and the position of the C(+)xG.C triplets on the thermodynamics of the triplexes were addressed under near physiological conditions. The interaction of metal ions with the triplexes clearly depended on the type and ionic strength of the cations, and the efficiency with which the cations stabilized the global triplex was in the order Mg(2+) > Mn(2+) > Ca(2+) > Ba(2+) >> Na(+). These observations would be useful for the design of triplex-forming oligonucleotides for antigene drugs and therapeutic purposes.

Development of novel peptide ligands modulating the enzyme activity of prostate-specific antigen

Prostate-specific antigen (PSA) is a serine proteinase produced mainly by epithelial cells of the prostate. Measurement of PSA in serum is widely used for diagnosis and monitoring of prostate cancer. The major problem of the PSA determination in early diagnosis is the high false positive rate due to benign prostatic hyperplasia, but the clinical accuracy can be improved by determining the proportions of various molecular forms of PSA. The main biological function of PSA is liquefaction of the seminal gel formed after ejaculation, but PSA has also been suggested to regulate invasiveness and metastatic potential of prostatic tumors. Thus, agents binding to and affecting the function of PSA have the potential to be used for diagnosis and therapy of prostate cancer. We have developed peptides specific for PSA by using cyclic phage display peptide libraries. After deducing the amino acid sequence of the peptides by sequencing the relevant part of phage genome, the peptides were expressed as glutathione-S-transferase (GST) fusion proteins or produced by chemical synthesis. The peptides were shown to bind to PSA specifically as indicated by lack of binding to other related serine proteinases. The binding of the peptides with PSA was strongly inhibited by monoclonal antibodies specific for free PSA and they did not bind to PSA-inhibitor complexes indicating that they bind close to the active site of the enzyme. Most of the peptides enhanced the enzyme activity of PSA against a chromogenic substrate. The affinity of the peptides could be increased by including Zn2+ in the reaction mixture. These results show that peptides that bind to PSA and modulate its enzyme activity can be developed by phage display techniques. These peptides have the potential to be used for targeting of prostatic tumors and diagnostics of prostate cancer.