Lipid products of phosphoinositide 3-kinase bind human profilin with high affinity

To gain insight into the physiological function of phosphoinositide 3-kinase (PI 3-kinase) lipid products, this study examines the interactions of the D-3 phosphoinositides with profilin and the consequent effects on actin dynamics and phosphoinositide turnover. Profilin, a ubiquitous actin-regulating protein, plays a putative role in regulating actin assembly and PLC-gamma 1 signaling in light of its unique interactions with actin and phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2]. Here we raise evidence that the affinity of profilin with the D-3 phosphoinositides is substantially higher than that of PtdIns(4,5)P2. The dissociation constants (Kd) are estimated to be 1.1 microM, 5.7 microM, and 11 microM for phosphatidylinositol 3,4-bisphosphate [PtdIns(3,4)P2], phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3], and PtdIns(4,5)P2, respectively. Spectroscopic data show that while all these phosphoinositides alter the tryptophan fluorescence of profilin in a similar fashion, the respective conformational effect on profilin is vastly different. Based on CD data, the alpha-helical contents of profilin in the presence of 8 molar equiv of PtdIns(4,5)P2, PtdIns(3,4,5)P3, and PtdIns(3,4)P2 are 17.4%, 11.5%, and 1.4%, respectively, vis-a-vis 9.4% for profilin alone. In contrast, no appreciable change in the fluorescence and CD spectra is observed when related inositol phosphates such as Ins(1,4,5)P3, Ins(1,3,4,5)P4, or Ins(1,3,4)P3 at comparable concentrations are tested. Evidence suggests that this differential recognition bears functional significance concerning the intricate roles of profilin and inositol lipids in modulating actin polymerization and PtdIns(4,5)P2 turnover. The relative potency of individual phosphoinositides in offsetting the inhibitory effect of profilin on actin assembly is PtdIns(3,4)P2 > PtdIns(3,4,5)P3 > PtdIns(4,5)P2, consistent with their relative binding affinity with profilin. Moreover, the inhibitory effect of profilin on PLC-gamma 1-mediated PtdIns(4,5)P2 hydrolysis is overcome by PtdIns(3,4)P2 and PtdIns(3,4,5)P3 through a combined effect of PLC-gamma 1 activation and preferential profilin binding. This D-3 phosphoinositide-mediated regulation may represent a new mechanism for controlling PtdIns(4,5)P2 turnover by PLC-gamma 1.

Controlling cell attachment on contoured surfaces with self-assembled monolayers of alkanethiolates on gold

This paper describes a method based on experimentally simple techniques--microcontact printing and micromolding in capillaries--to prepare tissue culture substrates in which both the topology and molecular structure of the interface can be controlled. The method combines optically transparent contoured surfaces with self-assembled monolayers (SAMs) of alkanethiolates on gold to control interfacial characteristics; these tailored interfaces, in turn, control the adsorption of proteins and the attachment of cells. The technique uses replica molding in poly(dimethylsiloxane) molds having micrometer-scale relief patterns on their surfaces to form a contoured film of polyurethane supported on a glass slide. Evaporation of a thin (< 12 nm) film of gold on this surface-contoured polyurethane provides an optically transparent substrate, on which SAMs of terminally functionalized alkanethiolates can be formed. In one procedure, a flat poly(dimethylsiloxane) stamp was used to form a SAM of hexadecanethiolate on the raised plateaus of the contoured surface by contact printing hexadecanethiol [HS(CH2)15CH3]; a SAM terminated in tri(ethylene glycol) groups was subsequently formed on the bare gold remaining in the grooves by immersing the substrate in a solution of a second alkanethiol [HS(CH2)11(OCH2CH2)3OH]. Then this patterned substrate was immersed in a solution of fibronectin, the protein adsorbed only on the methyl-terminated plateau regions of the substrate [the tri(ethylene glycol)-terminated regions resisted the adsorption of protein]; bovine capillary endothelial cells attached only on the regions that adsorbed fibronectin. A complementary procedure confined protein adsorption and cell attachment to the grooves in this substrate.

Reconsideration of testicular biopsy and follicle-stimulating hormone measurement in the era of intracytoplasmic sperm injection for non-obstructive azoospermia?

To determine the possibility of finding motile spermatozoa and spermatids in patients with high serum follicle stimulating hormone (FSH) and spermatogenetic disorders proven by pathology, 100 cases of male infertility were reviewed. Of these, 71 patients were found to have non-obstructive azoospermia or severe primary spermatogenetic disorders, and 20 had obstructive azoospermia. A prospective study of the most recent 51 cases was conducted. Multiple testicular tissue biopsies were examined by a pathologist and a well-trained gynaecological technician. The findings of spermatozoa, spermatids and serum FSH concentrations were compared among six different histological groups. It was concluded that 51.2% of the non-obstructive azoospermic and failed spermatogenetic patients had spermatids and even motile 'shaking' spermatozoa and should be re-evaluated. In the non-obstructive azoospermic patients here, almost all the motile spermatozoa and spermatids were found in patients with a serum FSH concentration of < 30 mIU/ml. It is suggested that a testicular biopsy should be conducted in every case of non-obstructive azoospermia and spermatogenetic disorder, even in those patients with elevated serum FSH concentrations.

Stimulation of an insulin receptor activates and down-regulates the Ca2+-independent protein kinase C, Apl II, through a Wortmannin-sensitive signaling pathway in Aplysia

Activation of tyrosine kinase-linked receptors has been shown to stimulate Ca2+-independent protein kinase C isoforms in nonneuronal cells. We have examined this signaling pathway in the nervous system. Incubating bag cell neurons from the marine mollusk Aplysia californica with concentrations of insulin known to stimulate a tyrosine kinase-linked receptor in these cells persistently activated and down-regulated the Ca2+-independent protein kinase C (Apl II), whereas insulin only transiently activated and did not down-regulate the Ca2+-activated protein kinase C (Apl I). The effects of insulin may be mediated by activation of phosphoinositide 3-kinase because (a) diC16phosphatidylinositol 3,4,5-trisphosphate, a synthetic phosphoinositide 3-kinase product, stimulated autophosphorylation of baculovirus-expressed Apl II, but not of Apl I, and (b) wortmannin, an inhibitor of phosphoinositide 3-kinase, blocked the activation and down-regulation of Apl II by insulin but not the transient activation of Apl I. These results suggest that activators of tyrosine kinase-linked receptors may mediate some of their effects in neurons through activation of Ca2+-independent protein kinase C isoforms.

Evaluation of polymerase chain reaction-restriction enzyme analysis of mycobacteria cultured in BACTEC 12B bottles

Polymerase chain reaction with restriction enzyme analysis (PRA) was first tested on 15 reference strains and 50 subcultured clinical isolates of mycobacteria according to the reference algorithm by Telenti et al [1]. Next, we evaluated the application of this method to 108 isolates from liquid media (BACTEC 12B). Of them, 15 M. tuberculosis complex and 81 mycobacteria other than tuberculosis (MOTT) had comparable results with both PRA and the BACTEC 460 TB systems. However, seven M. tuberculosis complex and three potentially pathogenic MOTT were identified by PRA rather than the BACTEC TB system. PRA seems to be an efficient method for the identification of mycobacteria to the species level and a good aid to detect potentially pathogenic mycobacteria, especially in mixed mycobacterial cultures.

Antagonistic effect of inositol pentakisphosphate on inositol triphosphate receptors

We present evidence that inositol 1,3,4,5,6-pentakisphosphate acts as an antagonist of inositol triphosphate receptors in vitro by dampening the activity of Ca(2+)-mobilizing inositol phosphates. This antagonism bears physiological significance as cells maintain substantial quantities of this phosphoinositol in the cytosol, especially during cell differentiation or proliferation. Over a concentration range from 30 to 150 microM, this pentakisphosphate causes a two- to five-fold increase in the EC50 values of inositol 1,4,5-trisphosphate and other active phosphoinositols in effecting Ca2+ efflux from brain microsomes. This specific inhibition results from competitive receptor binding, and is not noted with inositol hexaphosphate or related metabolites at comparable concentrations. Thus, inositol 1,3,4,5,6-pentakisphosphate in concert with other allosteric modulators may constitute an integral component for the receptor regulation.

Color Doppler sonogrphy in differentiation between testicular torsion and epididymoorchitis: report of three cases

Clinical assessment of the testicular torsion and epididymoorchitis is inherently difficult. Inadequate clinical information may prevent differentiation testicular torsion from non-surgical condition. We reported 3 cases with symptoms of acute scrotal condition who had received color Doppler sonography. One man had epididymoorchitis and color Doppler sonography showed profusely increased blood flow in the region of epididymis and testis. Symptoms subsided with one week of medical treatment. Sonography correctly detected absence of testicular perfusion in 2 boys who had sugical exploration of the scrotum. Testicular torsions were confirmed by surgical findings. Absence or markedly decreased testicular blood flow which indicated testicular ischemia or infarction was easily identified. Conversely, hyperemia of the testis and/or epididymis is usually associated with inflammation However, incomplete torsion or detorsion may demonstrate normal testicular flow on color Doppler sonography. Color Doppler sonography provides early diagnosis of acute testicular torsion, and prevents unnecessary scrotal exploration.

2'-Phospho-cyclic ADP-ribose, a calcium-mobilizing agent derived from NADP

Cyclic adenosine diphosphoribose (cADPR), a metabolite of NAD, appears to modulate changes in intracellular free Ca2+ levels by activation of ryanodine-sensitive Ca2+ channels. We report here that an ADPR cyclase purified from Aplysia californica readily catalyzes the conversion of NADP to 2'-phospho-cyclic adenosine diphosphoribose (2'-P-cADPR), cyclized at N-1 of the adenine moiety. An enzyme from canine spleen previously shown to contain NAD glycohydrolase, ADPR cyclase, and cADPR hydrolase activities also utilized NADP and 2'-P-cADPR as substrates. The apparent Km value for NADP was 1.6 microM compared with 9.9 microM for NAD, and the Vmax with NADP was twice that with NAD, indicating that 2'-P-cADPR is a likely metabolite in mammalian cells. 2'-P-cADPR was as active as cADPR in eliciting Ca2+ release from rat brain microsomes, but was unable to elicit Ca2+ release following conversion to 2'-P-ADPR by the action of canine spleen NAD glycohydrolase. 2'-P-cADPR and 1-D-myo-inositol 1,4,5-trisphosphate (IP3) appear to act by distinct mechanisms as microsomes desensitized to IP3 still released Ca2+ in response to 2'-P-cADPR and vice versa. Also, inhibition of IP3-induced Ca2+ release by heparin had no effect on release by 2'-P-cADPR. Both 2'-P-cADPR and cADPR appear to act by a similar mechanism based on similar kinetics of Ca2+ release, similar dose-response curves, cross-desensitization, and partial inhibition of release by procaine. The results of this study suggest that 2'-P-cADPR may function as a new component of Ca2+ signaling and a possible link between NADP metabolism and Ca2+ homeostasis.

Serum is a potent stimulator of keratinocyte tissue plasminogen activator expression

The plasminogen activator (PA) proteolytic cascade comprises two enzymes known as urokinase PA (uPA) and tissue PA (tPA), both of which activate plasminogen to plasmin. In normal human epidermis uPA is the predominant PA. In lesional epidermis from patients with a variety of cutaneous diseases, including psoriasis, pemphigus foliaceous, pemphigus, vulgaris, bullous pemphigoid, and benign chronic pemphigus, however, tPA is selectively elevated and becomes the predominant PA activity. The enhanced tPA is likely to be a reaction to the disease challenge rather than an initiating event in these clinically and etiologically diverse lesions. In the present study, cultured human keratinocytes, propagated under serum-free conditions, have been shown to respond to the addition of bovine or human serum with an increase in tPA activity and antigen. Furthermore, tPA is found predominantly in the suprabasal keratinocytes both in lesional epidermis and in stratified cultures that have been incubated for approximately 8 d in the presence of serum. These results suggest a possible mechanism by which epidermal tPA may be increased in diverse cutaneous lesions: The plasma infiltrated into lesional epidermis may stimulate the suprabasal keratinocytes in vivo to express tPA.

Pathological and biochemical modifications of renal function in ibuprofen-induced interstitial nephritis

Use of ibuprofen in patients with asymptomatic renal failure is known to produce acute renal toxicity. One of the manifestations is interstitial nephritis of which the pathogenic mechanism remains unclear. In the present study, this nephrotoxic syndrome was induced in rabbits by giving a single dose of uranyl nitrate, followed by consecutive doses of ibuprofen. This animal model thus allowed the assessment of renal functional and pathological changes associated with ibuprofen use in renal insufficiency. In these rabbits, the major abnormality appeared to be confined to the tubulointerstitial compartment. Microscopic examinations of the renal necropsy specimens showed tubular necrosis and interstitial lymphocytic infiltration. The histological finding of lymphocytic aggregation suggests that this nephrotoxic effect stems from a cytotoxic immune reaction in the interstitium. Moreover, levels of renal 2-arylpropionyl-CoA epimerase, a key enzyme involved in the metabolic inversion of ibuprofen, showed a significant reduction, which may result from the massive destruction of the tubular cells in these animals. These results support the premise that renal insufficiency is a prerequisite factor for ibuprofen-induced interstitial nephritis.

Non-invasive detection of ibuprofen in vivo 13C-NMR signals in rats

A non-invasive in vivo 13C-NMR experiment is performed to follow the metabolic pathway of ibuprofen in rats. Detection of possible intermediates and the stereoselectivity of ibuprofen chiral inversion process are discussed.

Phosphorylation of the platelet p47 phosphoprotein is mediated by the lipid products of phosphoinositide 3-kinase

Platelet stimulation by thrombin or the thrombin receptor activating peptide (TRAP) results in the activation of phosphoinositide 3-kinase and the production of the novel polyphosphoinositides phosphatidylinositol 3,4-bisphosphate (PtdIns-3,4-P2) and phosphatidylinositol 3,4,5-trisphosphate (PtdIns-3,4,5-P3). We have shown previously that these lipids activate calcium-independent protein kinase C (PKC) isoforms in vitro (Toker, A., Meyer, M., Reddy, K. K., Falck, J. R., Aneja, R., Aneja, S., Parra, A., Burns, D. J., Ballas, L. M. and Cantley, L. C. (1994) J. Biol. Chem. 269, 32358-32367). Activation of platelet PKC in response to TRAP is detected by the phosphorylation of the major PKC substrate in platelets, the p47 phosphoprotein, also known as pleckstrin. Here we provide evidence for two phases of pleckstrin phosphorylation in response to TRAP. A rapid phase of pleckstrin phosphorylation (< 1 min) precedes the peak of PtdIns-3,4-P2 production and is unaffected by concentrations of wortmannin (10-100 nM) that block production of this lipid. However prolonged phosphorylation of pleckstrin (> 2 min) is inhibited by wortmannin concentrations that block PtdIns-3,4-P2 production. Phorbol ester-mediated pleckstrin phosphorylation was not affected by wortmannin and wortmannin had no effect on purified platelet PKC activity. Phosphorylation of pleckstrin could be induced using permeabilized platelets supplied with exogenous gamma-32P[ATP] and synthetic dipalmitoyl PtdIns-3,4,5-P3 and dipalmitoyl PtdIns-3,4-P2 micelles, but not with dipalmitoyl phosphatidylinositol 3-phosphate or phosphatidylinositol 4,5-bisphosphate. These results suggest two modes of stimulating pleckstrin phosphorylation: a rapid activation of PKC (via diacylglycerol and calcium) followed by a slower activation of calcium-independent PKCs via PtdIns-3,4-P2.

Phosphatidylinositol (3,4,5)P3 interacts with SH2 domains and modulates PI 3-kinase association with tyrosine-phosphorylated proteins

Src homology 2 (SH2) domains on the regulatory subunit of phosphoinositide 3-kinase (PI 3-kinase) mediate its binding to specific tyrosine-phosphorylated proteins in stimulated cells. Using a pharmacological and genetic approach, we show that the amount of PI 3-kinase associated with tyrosine-phosphorylated proteins inversely correlates with the amount of PI 3-kinase lipid products present in the cell. An explanation for this observation is provided by our finding that phosphatidylinositol (3,4,5)trisphosphate (Ptdlns [3,4,5]P3) binds directly and selectively to the SH2 domains of the 85 kDa subunit of PI 3-kinase and thereby blocks binding to tyrosine-phosphorylated proteins. The SH2 domain of pp60C-STC also specifically bound Ptdlns (3,4,5)P3, and the binding was competed by a phosphopeptide specific for the Src SH2 domain. These results indicate that production of Ptdlns (3,4,5)P3 at the membrane disrupts the binding of PI 3-kinase to phosphoproteins. This lipid may also recruit other SH2-containing proteins to the membrane to initiate downstream signaling.

Color Doppler ultrasound used for screening varicocele: the clinical significance as compared to physical examination

The Acuson 128 XP color Doppler ultrasound (CDUS) unit has been applied to cases of infertility in the Chang Gung Memorial Hospital infertility clinic since November 1992. Seventy-four infertile males (group I) and 82 fertile cases (group II) with clinical obvious varicocele (detected by physical examination) were enrolled in this retrospective analysis. Subclinical varicocele (27%) may account for large group of the infertile men. It occurs almost bilaterally and can only be detected by CDUS. On the contrary, 26.8% of the cases with clinical obvious varicocele can be objectively ruled out by CDUS. Color Doppler ultrasound proved to be an easy, effective, convenient and noninvasive instrument for determining subclinical varicocele. It also helped to avoid unnecessary varicocelectomy in cases as judged by physical examination alone.

Preparation and characterization of a D-myo-inositol 1,4,5-trisphosphate-specific antibody

Antibodies against Ins(1,4,5)P3 were raised by immunizing rabbits with two types of InsP3-BSA conjugates which were synthesized by covalently coupling Ins(1,4,5)P3 to the carrier protein via alkyl linkages. The anti-Ins(1,4,5)P3 antibody was detected by a novel ELISA using Ins(1,4,5)P3-immobilized microtitre plates. Both antiserum preparations showed specific binding with Ins(1,4,5)P3, with titres of 1:4000. Most inositol phosphates, including Ins1P, Ins(4,5)P2, Ins(1,3,4)P3, Ins(1,5,6)P3, Ins(1,2,5,6)P1, Ins(3,4,5,6)P4, Ins(1,3,4,5,6)P5, InsP6, and PtdIns(4,5)P2, did not exhibit significant molecular interactions with the antibodies. Ins(1,3,4,5)P4, however, cross-reacted with these antibodies with one-third of the affinity as that of Ins(1,4,5)P3, in part due to the largely shared structural motifs. The differential affinity was significantly improved by affinity purification on Ins(1,4,5)P3-agarose. The affinity-purified antibody displayed IC50 values of 12 nM and 730 nM for Ins(1,4,5)P3 and Ins(1,3,4,5)P4 respectively, according to a competitive ELISA; these values are in line with those reported for the Ins(1,4,5)P3 receptor. The modes of ligand recognition at the binding sites of these two types of biomolecules are, however, different. Moreover, although the ligand binding was interfered with by multivalent anions such as ATP4-, HPO4(3-) and SO4(2-) at high concentrations, no inhibition was noted with heparin, an antagonist of the Ins(1,4,5)P3 receptor.

Brugia pahangi: effects of melanization on the uptake of nutrients by microfilariae in vitro

The effects of melanization on nutrient uptake by the microfilariae of Brugia pahangi were investigated by using in vitro melanization and autoradiographic techniques. It was found that the melanotic capsules which formed around the microfilariae in vitro completely inhibited the uptake of the following radiolabeled nutrients into microfilarial tissues: D-[6-3H]glucose, L-[4,5-3H]leucine, [2-3H]glycine, [1-14C]linoleic acid, [5,6,8,9,11,12,14,15-3H]arachidonic acid, [2,8-3H]adenine, [8-14C]guanine HCl, and [5,6-3H]uracil. These results provide strong evidence that melanization may kill the microfilariae by starvation.

Stereoselective disposition of ibuprofen in patients with compromised renal haemodynamics

1. The primary aim of this study was to assess the impact of renal haemodynamics on the pharmacokinetic behaviour of ibuprofen enantiomers. Thirty-two patients and ten age-matched healthy volunteers participated in this study. These patients had at least one of the following risk factors for cardiovascular disorders: hypertension, diabetes mellitus, hyperlipidaemia and hyperuricaemia with or without consequent complications such as coronary artery disease, congestive heart failure, cerebral vascular disease, and chronic renal failure. Renal function in these patients was thus characterized by unstable renal haemodynamics that might render them susceptible to ibuprofen-incurred renal damage. 2. Each subject received a single oral dose of 800 mg of racemic ibuprofen. The pharmacokinetic parameters of (S)- and (R)-ibuprofen, t 1/2(S), t 1/2(R), AUC(S), AUC(R), V/F(R), and CL/F(R), for each individual were determined from respective plasma concentration-time curves. To assess the effect of individual clinical conditions on the disposition of ibuprofen enantiomers, the arithmetic means of these pharmacokinetic parameters for each disease group were compared with those of the healthy volunteers by a t-test. 3. All of these disease groups showed elevated AUC(S) and higher (S)/(R) AUC ratios. These disease states along with gender and age were analyzed by multiple linear regression to discern significant factors for elevating AUC(S). Of these, advanced age (P = 0.02) and hypertension (P = 0.03) were identified as independent factors contributing to AUC(S) increase in this population. Thus, patients with these two clinical conditions are at particular risk from the adverse renal effect of ibuprofen.

Pore strain behaviour of collagen-glycosaminoglycan analogues of extracellular matrix

Mechanical properties of a highly porous collagen-glycosaminoglycan (CG) analogue of extracellular matrix were investigated. The stress-strain behaviour of the matrices displayed the typical concave-up shape characteristic of porous materials and soft tissues. Deformation behaviour of the material was further investigated using novel methodology to determine material strains at the micrometre level. Central to the methodology was the use of scanning electron microscopy (SEM) in conjunction with a digital image analyser. The method for strain determination at the micrometre level was verified by comparison with measurement of surface strain using an optical method. An unexpected finding in these materials is that Poisson's ratio varies with engineering strain. A geometrical/mathematical model was developed to explain this behaviour. These results encourage further investigation of the mechanical properties of these materials, in order to provide important insights into the physical microenvironment in which cells reside.

Ceramide as a modulator of endocytosis

The effects of ceramide analogs on the uptake of markers for fluid-phase (horseradish peroxidase, HRP) and receptor-mediated (low density lipoprotein, LDL) endocytosis were studied in Chinese hamster fibroblasts. N-Hexanoyl-D-erythro-sphingosine (C6-Cer) decreased the uptake of HRP in a dose-dependent manner. Internalization was inhibited > 40% with 25 microM C6-Cer, relative to controls, and was apparent within 5 min. Internalization of HRP was also inhibited by other Cer analogs and by treatment with agents that raise levels of endogenous Cer (sphingomyelinase or the glycosphingolipid synthesis inhibitor, 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP)), but not by N-hexanoyl-D-erythrosphinganine (C6-dihydro-Cer) or sphingosine. Internalization of LDL was also inhibited by C6-Cer in a concentration-dependent manner, but was less pronounced than the effect on HRP internalization (10% versus 40% inhibition with 25 microM C6-Cer), suggesting that ceramide might affect fluid-phase and receptor-mediated endocytosis to different extents. C6-Cer also slowed HRP and LDL transport from endosomes to lysosomes as studied by analysis of endocytic vesicles on Percoll density gradients and induced a redistribution of endocytic organelles as determined by fluorescence microscopy of intact cells using appropriate markers. This resulted in decreased degradation of 125I-labeled LDL in the presence of C6-Cer. These results suggest that endogenous ceramide may modulate endocytosis.

Epididymal sperm aspiration with assisted reproductive techniques: difference between congenital and acquired obstructive azoospermia?

From July 1992 to May 1994, 31 cases of obstructive azoospermia-induced infertility underwent 35 epididymal sperm aspiration procedures and assisted reproductive techniques. These included in-vitro fertilization (IVF), zygote intra-Fallopian transfer (ZIFT), subzonal insemination (SUZI) and intracytoplasmic sperm injection (ICSI) with embryo transfer or tubal embryos transfer. The motile spermatozoa were retrieved using a gauge 24 Medicut cannula and flush medium. Total oocyte fertilization rate was 23.4% and the clinical pregnancy rate was 12.5% (four out of 32 treatment cycles). Congenital absence of the vas deferens was found in 16 cases (51.6%) and secondary genital duct obstruction was present in 15 cases (48.4%). In all, 29 aspirations were retrieved from the caput of the epididymis and six from the epididymal body or tail. The fertilization rate for the caput spermatozoa was much less than that for other areas of the epididymis (P < 0.05). Though there were no predictable differences in fertilization rates between the congenital and acquired groups, by using epididymal spermatozoa for assisted reproduction, the congenital group seemed to have a stronger tendency to achieve pregnancy (20 versus 5.9%).

[Comparison of UW solution and UR (a modified Collins) solution for renal preservation in renal transplantation]

For the storage of human transplanted organs, the benefit of "UW solution" has been proven especially in keeping a longer preservation time for the liver and pancrease; however, the value for kidney preservation was still debated. A total of 293 cases of renal transplantation were performed over 12 years in our hospital and 206 cases were cadaveric transplants. The latter ones were further divided into 3 groups, according to the immunosuppressive medication and preservation solution used. In the CsA treated groups, the ATN rates significantly decreased in those preserved with the UW solution than with the UR solution. Although the UW solution did not improve the graft survival in our series, it did save the cost for postoperative hemodialysis and shorten the hospital stay which made it cost effective.

[Analysis of 117 cases of hypospadias--its location, operation and complication]

Hypospadias is a common congenital anomaly in male newborns. The incidence is about one in 300 live male births. In the U.S., about 6000 boys with hypospadias are born each year. For this study, we collected 117 recent (with the last 5 years) cases (88 fresh and 29 referred) who received an operation in our department. We calculated the hypospadias location and the complication rate with the desire of finding out the relationships between them. Our overall complication rate is 51.3% which is much higher than other recent studies and may be related to a different distribution of the hypospadias locations.

Biosynthesis of plasma factor XIII: evidence for transcription and translation in hepatoma cells

Factor XIIIa belongs to a family of ubiquitous transglutaminases, which catalyze formation of covalent bonds between the epsilon-amino group of specific lysines and the gamma-carboxyl group of glutamines. Factor XIII is synthesized as a zymogen and after activation, it participates in both the coagulation and fibrinolytic mechanisms. Most transglutaminases are intracellular, but factor XIII is both intracellular and extracellular. the biosynthesis of extracellular (plasma) factor XIII, with the structure of a noncovalent heterotetramer, A2B2, is complex. Here, evidence is presented from PCR analysis and Northern blotting that mRNAs for both A and B subunits are present in the liver. The distribution of mRNA, specific for factor XIII subunits, in various human tissues was also analyzed. Among the tissues examined, the only signal for B subunit was found in the liver. For subunit A, the signal was observed in placenta, liver, kidney, lung, skeletal muscle and heart with varying intensities; in brain or pancreas there was no signal. With an immunoperoxidase method, factor XIII A subunit was identified in the PLC/PRF/5 cell line. By ELISA and reverse immunoblotting, with antibodies specific for the A-B complex, it was also shown that these cells produce and secrete factor XIII. From all of these results, we conclude that the liver is a source of plasma factor XIII, and that the complex A2B2 is secreted from these cells.

A mapping study of 13 genes on human chromosome bands 4q11-->q25

A chromosome band 4q21 gene (MLLT2, formerly called AF-4/FEL) involved in a reciprocal translocation with chromosome band 11q23 in t(4;11) acute leukemia has been cloned. To provide better definition of gene order and relationships in this region where MLLT2 resides, we used pulsed field gel electrophoresis (PFGE) to investigate 13 genes (including MLLT2) with physical locations in bands 4q11-->q25. Somatic cell hybrids derived from RS4;11, a leukemic cell line carrying the t(4;11)(q21;q23), were also used to localize genes in relation to MLLT2. Linkage of the interleukin 8 (IL8), albumin (ALB), and platelet factor 4 (PF4) genes was confirmed by NotI, SalI and SacII digests. The maximum distance between PF4 and ALB is 210 kb and between ALB and IL8 is 420 kb. The alcohol dehydrogenase, class I (ADH2, ADH3) gene cluster can be linked to the alcohol dehydrogenase, class III gene (ADH5) by SacII, NruI, and EagI digests. The maximum distance between them is 590 kb. Our study indicated that ALB, alpha-fetoprotein (AFP), PF4, beta-thromboglobulin (PPBP), GRO1 (encoding a cytokine also called melanoma growth-stimulatory activity), and IL8 genes can be physically linked. In this study the gamma-interferon induced protein 10 (INP10), bone morphogenetic protein 3 (BMP3), annexin III (ANX3), KIT, amphiregulin (AREG), immunoglobulin J polypeptide (IGJ), deoxycytidine kinase (DCK) and MLLT2 genes were not linked to one another or to the above two groups of genes. Our analysis using somatic cell hybrids combined with previous reports demonstrated that the ADH gene cluster is telomeric to MLLT2 and KIT, ALB, AFP, PF4, beta TG, GRO1, IL8, ANX3, AREG and DCK are centromeric to MLLT2.

Use of a serum-free epidermal culture model to show deleterious effects of epidermal growth factor on morphogenesis and differentiation

The presence of serum has limited the utility of many culture models for the study of cytokine effects because its complexity and variability can confound the interpretation of data. In the present study, a serum-free skin co-culture model was used to investigate the effect of exogenous epidermal growth factor (EGF) on epidermal proliferation and differentiation. Human keratinocytes cultured on collagen rafts at the air-liquid interface produced a well-differentiated epithelium that resembled normal epidermis. Keratin filaments, membrane-coating granules, and keratohyalin granules were all observed. Epidermal differentiation markers keratin K1/K10, involucrin, and transglutaminase were localized in most of the suprabasal layers, whereas profilaggrin/filaggrin was confined to the granular layers and stratum corneum. In the continual presence of 10-20 ng/mL EGF, the epidermis was less organized, thinner, and less proliferative. EGF also depressed several indicators of differentiation: The number of keratohyalin granules and membrane-coating granules was greatly decreased; antigen expression of profilaggrin/filaggrin appeared diminished by immunocytochemical staining; frequent nuclear retention was noted in the relatively thickened stratum corneum-like layers. As detected by immunohistochemical staining, the expression of EGF receptor in the epidermis was reduced by exogenous EGF. These data illustrate that EGF cannot be considered a simple mitogen. Our findings also underscore the importance of using sophisticated culture models to assess complex cytokine effects that may be dependent on the architecture of a differentiating epidermis.

Hidden Markov model approach to skill learning and its application to telerobotics

In this paper, we discuss the problem of how human skill can be represented as a parametric model using a hidden Markov model (HMM), and how an HMM-based skill model can be used to learn human skill. HMM is feasible to characterize a doubly stochastic process--measurable action and immeasurable mental states--that is involved in the skill learning. We formulated the learning problem as a multidimensional HMM and developed a testbed for a variety of skill learning applications. Based on "the most likely performance" criterion, the best action sequence can be selected from all previously measured action data by modeling the skill as an HMM. The proposed method has been implemented in the teleoperation control of space station robot system, and some important implementation issues have been discussed. The method allows a robot to learn human skill in certain tasks and to improve motion performance.

Molecular interactions of endogenous D-myo-inositol phosphates with the intracellular D-myo-inositol 1,4,5-trisphosphate recognition site

A systematic effort was made to elucidate the mode of recognition at the inositol 1,4,5-trisphosphate-specific receptor. Eleven D-myo-inositol phosphates were synthesized and tested for Ca(2+)-mobilizing and receptor-binding activities, which included Ins(1,3,4,5,6)P5, Ins(1,2,5,6)P4, Ins(1,3,4,5)P4, Ins(1,3,4,6)P4, Ins(1,4,5,6)P4, Ins(3,4,5,6)P4, Ins(1,3,4)P4, Ins(1,4,5)P3, Ins(1,5,6)P3, Ins(1,4)P2, and Ins(4,5)P2. Of these, Ins(1,4,5)P3, Ins(1,3,4,6)P4, Ins(1,3,4,5)P4, Ins(1,4,5,6)P4, and Ins(4,5)P2 were able to elicit Ca2+ release from rat brain microsomes. Binding experiments suggest that the ability of these polyphosphates to effect Ca2+ mobilization arises from interactions with the Ins(1,4,5)P3-specific receptor. Accordingly, a model accounting for the ligand recognition is proposed. The Ins(1,4,5)P3-binding site is presumably composed of two domains. The anchoring domain binds the 4,5-bisphosphate 6-hydroxy motif. Disruption of this structural feature abolishes the agonist activity. The auxiliary domain exerts long-range interactions with the 1-phosphate, thus enhancing the binding affinity. The stereochemical requirement for this electrostatic interaction is, however, less stringent. Evidence suggests that Ca(2+)-mobilizing inositol phosphates are able to effect productive binding by assuming conformations displaying or mimicking these essential structural features.

Assessment of ibuprofen-associated nephrotoxicity in renal dysfunction

Ibuprofen-incurred nephrotoxicity in renal insufficiency was assessed by examining renal functional and pathological changes in rabbits with pre-existing renal failure after receiving consecutive doses of ibuprofen. The pharmacokinetic behavior of ibuprofen enantiomers in rabbits with renal dysfunction appeared to qualitatively parallel that of their human counterparts. Modifications of the pharmacokinetic profile occurred in a stereoselective fashion: (R)-ibuprofen disposition was independent of renal conditions, whereas (S)-ibuprofen clearance was significantly hampered. Pathological damage associated with ibuprofen use in renal dysfunction was evident from the renal necropsy specimens, which was characterized by tubular necrosis and interstitial nephritis. This animal model study indicates clearly that renal insufficiency is a causative factor for ibuprofen-induced interstitial nephritis. Moreover, based on the evidence of interstitial lymphocytic infiltration, this nephrotoxic syndrome is assumed to be a manifestation of a disordered cellular immunity.

The effect of single bolus dose of esmolol for controlling the tachycardia and hypertension during laryngoscopy and tracheal intubation

Tachycardia and hypertension usually accompany laryngoscopy and tracheal intubation. This response is undesirable, especially in patients with cardiovascular or intracranial diseases. Esmolol is a cardioselective, ultrashort-acting beta adrenergic blocking agent with a very short half-life. The efficacy of bolus dose of esmolol in blunting hemodynamic responses during laryngoscopy and tracheal intubation was evaluated. 45 patients (15 in each group) of ASA physical status I and II scheduled for elective non-cardiac surgery were included in this randomized, placebo-controlled study. At time zero, the study preparation (placebo, 100 or 200 mg of esmolol) was administered intravenously, followed by thiopentone 5 mg/kg and succinylcholine 1.5 mg/kg for induction. Tracheal intubation was performed 2 minutes after time zero. Anesthesia was maintained with 50% nitrous oxide and 1.0 MAC halothane in oxygen, and vecuronium 0.08 mg/kg. Heart rate (HR) and systolic blood pressure (SBP) were recorded every minute for 10 minutes. To compare with the placebo group, there was a significant decrease in either HR or SBP in 200 mg group in the 8 minutes course after intubation (p < 0.05). There was a significant decrease in HR in the 100 mg group at the 3rd, 4th, and 5th minutes when compared with the placebo group (p < 0.05). The differences in SBP between the 100 mg group and placebo group were significant at the 3rd and 4th minutes (p < 0.05). Both bolus dosages of esmolol could effectively attenuate the tachycardia and hypertension produced by laryngoscopy and tracheal intubation. Furthermore, esmolol 200 mg presented a better hemodynamic stability than esmolol 100 mg during induction of anesthesia.

Novel function of phosphatidylinositol 4,5-bisphosphate as a cofactor for brain membrane phospholipase D

The activation of phospholipase D (PLD) is a receptor-mediated event that has been implicated in signal transduction and membrane traffic in eukaryotic cells. Little is known about the biochemical and molecular properties of signal-activated PLDs, and none has been isolated. Here we report that phosphatidylinositol 4,5-bisphosphate (PIP2) potently stimulates brain membrane PLD activity in vitro in a highly specific manner. PIP2 increases 10-fold the maximal activity of a partially purified PLD with an EC50 of < 0.5 mol %. Other acidic phospholipids, including phosphatidylinositol 4-phosphate, phosphatidylinositol, phosphatidylserine, and phosphatidic acid, are completely or nearly ineffective. Neomycin, a high affinity ligand of PIP2, inhibits membrane-bound PLD but has no effect on the activity of a detergent-solubilized or partially purified enzyme. The addition of PIP2 restores the sensitivity of partially purified PLD to neomycin inhibition, indicating that neomycin blocks membrane PLD activity by binding to endogenous PIP2. These results define a novel function of PIP2 as a cofactor for brain membrane PLD and suggest that PIP2 synthesis and hydrolysis could be important determinants in regulating PLD action in signal transduction and membrane transport.

Deoxyribonucleic acid flow cytometric study in pheochromocytomas and its correlation with clinical parameters

OBJECTIVES

To study deoxyribonucleic acid flow cytometry (DNA-FC) in pheochromocytomas and its correlation with clinical parameters.

METHODS

Fifty cases of pheochromocytomas of a total of 58 cases were studied for DNA-FC from archival paraffin-embedded tissue blocks and were correlated with clinical parameters (ie, size of tumor, benign or malignant pathologic type, vanillymandelic acid [VMA] level in 24 hour urine, age, sex, duration of symptoms, symptom scores).

RESULTS

A total of 19 cases were diploid while 31 cases (62%) showed DNA aneuploidy with 21 cases tetraploid. Four cases were malignant. All of them were tetraploid. However, among the 46 benign cases, 10 were aneuploid and 17 were tetraploid. All 19 cases with DNA diploidy were benign. The DNA-FC did not correlate with other clinical parameters in our study.

CONCLUSIONS

We confirmed a high incidence of DNA aneuploidy in pheochromocytomas. All malignant pheochromocytomas were tetraploid and all cases with DNA diploidy were benign. Long-term follow-up of all cases, especially those with DNA aneuploidy (including tetraploidy), is mandatory.

A drug dissolution monitor employing multiple fiber optic probes and a UV/visible diode array spectrophotometer

A traditional dissolution pumping system was recently replaced with a fiber optic interface between the spectrometer and the samples. However, the system was limited to a single sample vessel. In this study, a dissolution testing system with six vessels connected to a diode array spectrometer via six optical fibers was investigated. A bifurcated fiber optic bundle was used to transfer the light from the source to the dissolution vessels and was networked so that spectra of each sample can be measured periodically. A full spectrum calibration method based on Principal Component Regression (PCR) was used to determine the concentrations of active ingredients and to account for interferences due to excipients in tablet formulations. Results on this new fiber optic interface system are compared with those obtained previously with the traditional pumping system. Standard errors of prediction are between 1.5 and 3.2% using cross-validation and between 1.1 and 1.7% for the direct validation of two active ingredients in two different drug formulations.

L-carnitine via enzyme-catalyzed oxidative kinetic resolution

L-Carnitine of high optical purity was prepared via kinetic resolution using a mutant strain of Acinetobacter calcoaceticus ATCC 39647. This organism preferentially metabolized the D-enantiomer of the racemate to furnish L-carnitine. Recovery of L-carnitine was 93%, providing a total weight yield of 46.5% in 92% enantiomeric excess. The mode of degradation of carnitine was shown to proceed via a monooxygenase-catalyzed oxidative cleavage resulting in the formation of trimethylamine and malic acid. The data suggest that the stereoselective metabolism of DL-carnitine is probably the result of differential permeability of the cell membrane towards the optical antipodes.

[Detection of serum anti-histone antibodies in patients with ankylosing spondylitis and its clinical significance]

Serum anti-total and subtypical histone antibodies were detected with ELISA and Western-Blotting in 78 ankylosing spondylitis (AS) and 38 gouty arthritis (GA) patients as well as in 45 normal subjects. The results showed that the positive rate of anti-histone antibodies (AHA) was about 5% in normal subjects or GA patients and 24.4% in AS patients. The mean level of AHAs was much higher in AS group than those in the controls. IgG- and IgM-AHA levels in AS patients during active stage were higher than in those during inactive stage. AHA levels were much more elevated in AS patients with present illness or past history of uveitis than in those without. The high levels of AHAs (especially anti-H3 antibody) were associated with uveitis in AS patients. The results suggested that the high level of AHAs might be a monitoring parameter for disease activity and occurrence of uveitis in patients with AS.

Renal malacoplakia with secondary hepato-duodenal involvement

Renal parenchymal malacoplakia is uncommon, and coexistence of extensive invasion into the liver and duodenum is extremely rare. Typically, there is an associated long-term urinary tract infection. We report on a 53-year-old woman with a history of diabetes and recurring pyelonephritis, who presented with a renal tumor and upper gastrointestinal bleeding. Surgical intervention included radical nephrectomy, lymphadenectomy, segmental hepatectomy, cholecystostomy, duodenorrhaphy, jejunostomy and appendectomy. There was no surgical morbidity. A pathologist confirmed the diagnosis of malacoplakia. All of the diagnostic criteria, including hematoxylin and eosin stain, iron stain, calcium stain and electron microscopy of Michaelis-Gutmann bodies, were classic. The literature is reviewed.

Expression of plasminogen activator inhibitor type 2 in normal and psoriatic epidermis

The plasminogen activator (PA) proteolytic cascade has been implicated in the regulation of cell activities, including proliferation and differentiation, both of which occur continuously in normal human epidermis and are aberrant in psoriatic epidermis. To elucidate further the mechanisms by which PA is regulated in epidermis, we evaluated the levels of PA inhibitors type 1 (PAI-1) and type 2 (PAI-2) in normal and psoriatic epidermis. PAI-2, but not PAI-1, was detectable by mRNA, antigen, and activity assays, indicating that PAI-2 is the predominant epidermal PA inhibitor. In situ hybridization revealed that PAI-2 mRNA occurred throughout normal epidermis, although the signal was most intense in the granular layers. Similarly, PAI-2 antigen was most prominent in the granular layers; its distribution in these differential layers was along the cell periphery. Diffuse, fainter staining for PAI-2 was also detected in the basal cells and in some spinous layers of normal epidermis. Extracts of normal epidermis contained PA inhibitory activity identified as PAI-2 by immunoprecipitation with specific antibody. In psoriatic epidermis, PAI-2 mRNA and antigen were most prominent in the more superficial layers beneath the cornified cells. As with normal epidermis, PAI-2 assumed a pericellular distribution in the psoriatic cells. These data demonstrate that PAI-2 is constitutively expressed in vivo by keratinocytes in human epidermis and indicate that this protein is the predominant inhibitor of PA activity in normal and psoriatic human epidermis.

Stereoselective disposition of ibuprofen in patients with renal dysfunction

Ibuprofen-induced acute renal failure is thought to occur in clinical conditions where maintenance of renal function is prostaglandin-dependent. In this study we used a pharmacokinetic approach to assess the predisposing factors for this therapeutic pitfall. The pharmacokinetics of ibuprofen enantiomers was examined after a single dose of 800 mg of racemic ibuprofen in three groups of subjects: A) patients with pre-existing renal failure (n = 10); B) patients with underlying disease states other than renal failure (n = 11); and C) age-matched healthy controls (n = 10). Most of the patients with renal insufficiency showed elevated plasma (S)-ibuprofen levels, higher area under plasma concentration vs. time curve for (S)-ibuprofen and increased area under plasma concentration vs. time curves for (S)-/(R)-ibuprofen ratios as compared with their healthy counterparts. It appeared that the extent of metabolic activation of (R)-ibuprofen to the (S)-isomer in renally compromised patients was greater than that in a normal setting. Consequently, in susceptible patients, reduced renal clearance coupled with concomitant metabolic inversion leads to elevated (S)-ibuprofen levels which may exacerbate the ischemic effect as a result of the accentuated blockage of prostaglandin synthesis.

Molecular rearrangements of the MLL gene are present in most cases of infant acute myeloid leukemia and are strongly correlated with monocytic or myelomonocytic phenotypes

Cytogenetic studies have previously identified abnormalities of chromosome band 11q23 in many cases of infant acute leukemia. Recent studies by ourselves and others have demonstrated breakpoint clustering in acute leukemias bearing translocations involving 11q23, and a Drosophila trithorax gene homologue (called MLL, HRX, or ALL-1) has been shown to span the 11q23 breakpoints of these translocations. To determine if this gene is affected in infant acute myeloid leukemia (AML), we have analyzed 26 infant AML cases for molecular alterations of this 11q23 gene. 15 out of 26 cases studied (58%) showed rearrangement of the MLL gene at the molecular level, and these rearrangements were clustered within an approximately 11-kb region containing nine exons of this gene. Moreover, 14 of the 15 cases with 11q23 rearrangements (93%) had myelomonocytic or monocytic phenotypes (M4 or M5 FAB subtypes, respectively), both of which are associated with a poor prognosis in childhood AML. In contrast, only 1 of 11 nonrearranged cases had an M4 or M5 phenotype (P = 0.00002). Rearrangement also correlated significantly with hyperleukocytosis (P = 0.02), another clinical parameter associated with poor outcome in this disease. Our results demonstrate that molecular rearrangements of MLL are common in M4 or M5 infant AML, and suggest that alteration of this gene may result in abnormal control of proliferation and differentiation in monocytic progenitor cells.

D-myo-inositol 1,4,5-trisphosphate analogues as useful tools in biochemical studies of intracellular calcium mobilization

Two types of structural variants of D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] were prepared by a chemoenzymatic route. These 6-O-substituted analogues retained the biological activity of Ins(1,4,5)P3, and were able to elicit Ca2+ release from porcine brain microsomes. Moreover, these derivatives allowed the preparation of Ins(1,4,5)P3-based immunogens and affinity matrix which were successfully applied to the preparation and purification of antibodies against Ins(1,4,5)P3. These antibodies displayed discriminative affinity towards Ins(1,4,5)P3, and provide a useful tool to study intracellular Ca2+ mobilization.

Monitoring of cyclosporin A levels with radioimmunoassay in renal transplant recipients: comparison of monospecific and nonspecific assays

Patients receiving cyclosporin A (CsA) therapy should be monitored carefully in order to avoid side effects and maintain immunosuppression. Radioimmunoassay is one of the most commonly used methods of monitoring CsA levels. The decision to use whole blood vs plasma or monospecific vs nonspecific monoclonal antibodies for the measurement of CsA levels has been a controversial issue. In this study, CsA levels in the whole blood and plasma were measured simultaneously with INCSTAR specific monoclonal antibodies in 20 renal transplant recipients (group A). There was a significant correlation between the CsA levels in the whole blood and plasma (R2 = 0.7379, p < 0.00001). However, at the therapeutic limit, the correlation was not good. The whole blood/plasma CsA concentration ratios were not correlated with the hematocrits of the patients. In another group of 20 renal transplant recipients (group B), CsA levels in whole blood and plasma were measured simultaneously with INCSTAR nonspecific monoclonal antibodies. There was a significant correlation between the CsA levels in whole blood and plasma (R2 = 0.6714, p < 0.00001). The whole blood/plasma ratios were significantly correlated with the hematocrits (R2 = 0.5457, p = 0.0002). The later finding could be due to the extensive cross-reactivity of nonspecific monoclonal antibodies with CsA metabolites, which are almost exclusively bound to the erythrocytes. The hematocrits in renal transplant recipients usually show significant change over a period of time. The plasma level may be more stable in such cases. However, measurement of whole blood levels also has several advantages, mainly from a technical aspect.(ABSTRACT TRUNCATED AT 250 WORDS)

[Transtympanic electrocochleography in Menière's disease]

In order to examine the usefulness of the electrocochleography (ECoG) in the diagnosis of Menière's disease and establish the diagnostic criteria in Chinese, transtympanic ECoG was performed on 18 normal ears, 22 Menière's ears and 14 ears with cochlear type sensorineural hearing loss other than Menière's disease. Although the Menière's ears had larger mean summating potential (SP) than the normal ears, the difference between both groups was not statistically significant. The mean amplitude and latency of the action potential (AP) in Menière's ears decreased and elongated significantly, but neither was sensitive enough in diagnosing Menière's disease. The SP/AP amplitude ratio not only made significant difference among 3 groups, but also had good diagnostic sensitivity (59.1%) and specificity (92%) in diagnosing Menière's disease while using the 95% upper confidence limit of the normative data (i.e., 34%). The SP/AP amplitude ratio of Menière's ears tended to increase while the mean hearing level of 4-8 KHz deteriorated. Also, abnormal enlargement of the SP/AP amplitude ratio in Menière's disease tended to be the result of decreased AP amplitude.

[Pheochromocytoma nuclear pattern analysis by flow cytometry]

Flow cytometric nuclear DNA analyses were performed on paraffin-embedded tissue samples taken from 39 patients with pheochromocytoma treated between 1981 and 1992. The Hedley technique was used for measurement of nuclear DNA contents. Only 30 cases out of the 39 tumors were available for the determination of DNA ploidy analyses. Ten cases (33.3%) showed a diploidy pattern, 8-cases (27%) showed an aneuploidy pattern and 12 cases (40%) revealed a tetraploidy pattern. Four cases of malignant pheochromocytoma with regional or distal metastasis had been noted during a mean follow-up period of 4.75 years. All these four cases showed tetraploidy nuclear pattern with vascular invasion on pathological examination, which was statistically significant (p < 0.001) in differentiation between benign and malignant pheochromocytoma. About one third of patients with tetraploidy appeared to have malignant tendencies and this was statistically significant (p < 0.05). None of the patients with either diploidy or aneuploidy pattern had disease progression. The location of the tumor (adrenal vs. extra-adrenal) and 24 hours urine total vanillylmandelic acid (VMA) amounts were not significantly different from the diploid, aneuploid or tetraploid groups. These results suggested that nuclear DNA ploidy pattern is an important independent, and useful prognostic factor for patients with pheochromocytoma.