Effects of D-serine treatment on outer retinal function

The role of the N-Methyl-D-Aspartate Receptor (NMDAR) in the outer retina is unclear despite expression of the NMDAR-complex and its subunits in the outer retina. The flash-electroretinogram (fERG) offers a non-invasive measurement of the retinal field potentials of the outer retina that can serve to clarify NMDAR contribution to early retinal processing. The role of the NMDAR in retinal function was assessed using a genetic mouse model for NMDAR hypofunction (SR^-/-), where the absence of the enzyme serine racemase (SR) results in an 85% reduction of retinal D-serine. NMDAR hypo- and hyperfunction in the retina results in alterations in the components of the fERG. The fERG was examined after application of exogenous D-serine to the eye in order to determine whether pre- and post-topical delivery of D-serine would alter the fERG in SR^-/- mice and their littermate WT controls. Amplitude and implicit time of the low-frequency components, the a- and b-wave, were conducted. Reduced NMDAR function resulted in a statistically significantly delayed a-wave and reduced b-wave in SR^-/- animals. The effect of NMDAR deprivation was more prominent in male SR^-/- mice. A hyperfunction of the NMDAR, through exogenous topical delivery of 5 mM D-serine, in WT mice caused a significantly delayed a-wave implicit time and reduced b-wave amplitude. These changes were not observed in female WT mice. There were temporal delays in the a-wave and amplitude and a decrease in the b-wave amplitude and implicit time in both hypo- and NMDAR hyperfunctional male mice. These results suggest that NMDAR and D-serine are involved in the retinal field potentials of the outer retina that interact based on the animal's sex. This implicates the involvement of gonadal hormones and D-serine in retinal functional integrity.

High production of d-psicose from d-fructose by immobilized whole recombinant Bacillus subtilis cells expressing d-psicose 3-epimerase from Agrobacterium tumefaciens

d-Psicose 3-epimerase (DPEase) can catalyze the isomerization of d-fructose to be rare sugar d-psicose, which has wide application prospects in the food and medical fields. In this study, the DPEase gene from Agrobacterium tumefaciens was constructed into plasmid pMA5, and was successfully expressed in the host Bacillus subtilis WB600 (B. subtilis). After optimization of the fermentation conditions, whole recombinant B. subtilis WB600/pMA5-At-DEPase(O) cells produced d-psicose from d-fructose with a conversion rate of 29.01 ± 0.19%, which could be used for the efficient synthesis of d-psicose. To further improve the whole recombinant B. subtilis application, B. subtilis cells were immobilized onto a gel bead biocatalyst by Ca-alginate. After optimization of the biotransformation conditions, the conversion rate of the immobilized biocatalyst reached 20.74 ± 0.39%, which was lower than the free cells. However, the results showed that the immobilized biocatalyst had higher thermal/pH stability and storability, and the gel beads could be recycled for at least six batches. The results showed that the amount of d-psicose generated reached 32.83 ± 2.56 g/L with the immobilized biocatalyst after six times biotransformation, whereas the free cells produced only approximately 10.44 ± 0.07 g/L. The results showed that immobilized recombinant B. subtilis cells are promising to use for the efficient synthesis of d-psicose.

SIRT3 controls brown fat thermogenesis by deacetylation regulation of pathways upstream of UCP1

OBJECTIVE

Brown adipose tissue (BAT) is important for thermoregulation in many mammals. Uncoupling protein 1 (UCP1) is the critical regulator of thermogenesis in BAT. Here we aimed to investigate the deacetylation control of BAT and to investigate a possible functional connection between UCP1 and sirtuin 3 (SIRT3), the master mitochondrial lysine deacetylase.

METHODS

We carried out physiological, molecular, and proteomic analyses of BAT from wild-type and Sirt3KO mice when BAT is activated. Mice were either cold exposed for 2 days or were injected with the β3-adrenergic agonist, CL316,243 (1 mg/kg; i.p.). Mutagenesis studies were conducted in a cellular model to assess the impact of acetylation lysine sites on UCP1 function. Cardiac punctures were collected for proteomic analysis of blood acylcarnitines. Isolated mitochondria were used for functional analysis of OXPHOS proteins.

RESULTS

Our findings showed that SIRT3 absence in mice resulted in impaired BAT lipid use, whole body thermoregulation, and respiration in BAT mitochondria, without affecting UCP1 expression. Acetylome profiling of BAT mitochondria revealed that SIRT3 regulates acetylation status of many BAT mitochondrial proteins including UCP1 and crucial upstream proteins. Mutagenesis work in cells suggested that UCP1 activity was independent of direct SIRT3-regulated lysine acetylation. However, SIRT3 impacted BAT mitochondrial proteins activities of acylcarnitine metabolism and specific electron transport chain complexes, CI and CII.

CONCLUSIONS

Our data highlight that SIRT3 likely controls BAT thermogenesis indirectly by targeting pathways upstream of UCP1.

Efficient production of lactulose from whey powder by cellobiose 2-epimerase in an enzymatic membrane reactor

In this study, the gene encoding cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus (CsCE) was successfully expressed in Bacillus subtilis WB800. After the fermentation medium optimization, the activity of recombinant strain was 4.5-fold higher than the original medium in a 7.5L fermentor. The optimal catalytic pH and temperature of crude CsCE were 7.0 and 80°C, respectively. An enzymatic synthesis of lactulose was developed using cheese-whey lactose as its substrate. The maximum conversion rate of whey powder obtained was 58.5% using 7.5 U/mL CsCE. The enzymatic membrane reactor system exhibited a great operational stability, confirmed with the higher lactose conversion (42.4%) after 10 batches. To our best knowledge, this is the first report of lactulose synthesis in food grade strain, which improve the food safety, and we not only realize the biological production of lactulose, but also make good use of industrial waste, which have positive impact on environment.

AIBP Limits Angiogenesis Through γ-Secretase-Mediated Upregulation of Notch Signaling

RATIONALE

Angiogenesis improves perfusion to the ischemic tissue after acute vascular obstruction. Angiogenesis in pathophysiological settings reactivates signaling pathways involved in developmental angiogenesis. We showed previously that AIBP (apolipoprotein A-I [apoA-I]-binding protein)-regulated cholesterol efflux in endothelial cells controls zebra fish embryonic angiogenesis.

OBJECTIVE

This study is to determine whether loss of AIBP affects angiogenesis in mice during development and under pathological conditions and to explore the underlying molecular mechanism.

METHODS AND RESULTS

In this article, we report the generation of AIBP knockout (Apoa1bp^-/-) mice, which are characterized of accelerated postnatal retinal angiogenesis. Mechanistically, AIBP triggered relocalization of γ-secretase from lipid rafts to nonlipid rafts where it cleaved Notch. Consistently, AIBP treatment enhanced DLL4 (delta-like ligand 4)-stimulated Notch activation in human retinal endothelial cells. Increasing high-density lipoprotein levels in Apoa1bp^-/- mice by crossing them with apoA-I transgenic mice rescued Notch activation and corrected dysregulated retinal angiogenesis. Notably, the retinal vessels in Apoa1bp^-/- mice manifested normal pericyte coverage and vascular integrity. Similarly, in the subcutaneous Matrigel plug assay, which mimics ischemic/inflammatory neovascularization, angiogenesis was dramatically upregulated in Apoa1bp^-/- mice and associated with a profound inhibition of Notch activation and reduced expression of downstream targets. Furthermore, loss of AIBP increased vascular density and facilitated the recovery of blood vessel perfusion function in a murine hindlimb ischemia model. In addition, AIBP expression was significantly increased in human patients with ischemic cardiomyopathy.

CONCLUSIONS

Our data reveal a novel mechanistic connection between AIBP-mediated cholesterol metabolism and Notch signaling, implicating AIBP as a possible druggable target to modulate angiogenesis under pathological conditions.

[Clinicopathological features and differential diagnosis of metanephric adenoma: a report of sixteen cases]

OBJECTIVE

To study the clinicopathological features and differential diagnosis of metanephric adenoma (MA).

METHODS

The clinicopathological data of 16 cases with MA diagnosed and treated in Peking University First Hospital from 2004 to 2016 were retrospectively analyzed, and the clinical characteristics, pathologic parameters, differential diagnosis, treatment options and prognosis of MA were analyzed with literature review.

RESULTS

The patients included 10 females and 6 males. The age of patients ranged from 14 to 83 years (mean=33.7 years). The partial nephrectomy was carried out for most patients. All cases were located in renal codex with 3 growing into the renal sinus. Histologically, the tumor was composed of tubules, papillary or glomeruloid structures and psammoma bodies were focally seen. Immunohistochemical study showed that all the cases expressed vimentin, and 94% cases expressed CD57, 63% WT1, 75% AE1/AE3, 19% cytokeratin 7 (CK7) and 13%α-methylacyl-CoA racemase (AMACR), and negative expressions for MA included CD10, neuron-specific enolase (NSE) and CD56. Follow-up information from 1 to 125 months was available in all the patients; and none of the patients showed any evidence of recurrence and metastasis.

CONCLUSION

The benign tumor characteristics of MA are not obvious for preoperative imaging diagnosis, and the diagnosis of MA should be based on the unique pathological features. Positive immunostain of CD57 is a useful indicator for MA diagnosis and differential diagnosis. The partial nephrectomy surgical treatment can achieve good clinical cure with good prognosis.

Crystal structure of maize serine racemase with pyridoxal 5'-phosphate

Serine racemase (SR) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that is responsible for D-serine biosynthesis in vivo. The first X-ray crystal structure of maize SR was determined to 2.1 Å resolution and PLP binding was confirmed in solution by UV-Vis absorption spectrometry. Maize SR belongs to the type II PLP-dependent enzymes and differs from the SR of a vancomycin-resistant bacterium. The PLP is bound to each monomer by forming a Schiff base with Lys67. Structural comparison with rat and fission yeast SRs reveals a similar arrangement of active-site residues but a different orientation of the C-terminal helix.

In vivo magnetic resonance studies reveal neuroanatomical and neurochemical abnormalities in the serine racemase knockout mouse model of schizophrenia

BACKGROUND

Decreased availability of the N-methyl-D-aspartate receptor (NMDAR) co-agonist D-serine is thought to promote NMDAR hypofunction and contribute to the pathophysiology of schizophrenia, including neuroanatomical abnormalities, such as cortical atrophy and ventricular enlargement, and neurochemical abnormalities, such as aberrant glutamate and γ-aminobutyric acid (GABA) signaling. It is thought that these abnormalities directly relate to the negative symptoms and cognitive impairments that are hallmarks of the disorder. Because of the genetic complexity of schizophrenia, animal models of the disorder are extremely valuable for the study of genetically predisposing factors. Our laboratory developed a transgenic mouse model lacking serine racemase (SR), the synthetic enzyme of d-serine, polymorphisms of which are associated with schizophrenia. Null mutants (SR-/-) exhibit NMDAR hypofunction and cognitive impairments. We used 9.4 T magnetic resonance imaging (MRI) and proton spectroscopy (MRS) to compare in vivo brain structure and neurochemistry in wildtype (WT) and SR-/- mice.

METHODS

Mice were anesthetized with isoflurane for MRI and MRS scans.

RESULTS

Compared to WT controls, SR-/- mice exhibited 23% larger ventricular volumes (p<0.05). Additionally, in a medial frontal cortex voxel (15 μl), SR-/- mice exhibited significantly higher glutamate/water (12%, t=1.83, p<0.05) and GABA/water (72%, t=4.10, p<0.001) ratios.

CONCLUSIONS

Collectively, these data demonstrate in vivo neuroanatomical and neurochemical abnormalities in the SR-/- mouse comparable to those previously reported in humans with schizophrenia.

Paneth cell-like change in benign prostate can account for P504S (AMACR) reactivity

Paneth cell-like neuroendocrine metaplasia of benign and cancerous prostate was described in 1992. Here, we note that P504S (AMACR), the cytoplasmic marker for prostate cancer used alone or in concert with basal cell markers, can be strongly reactive in benign prostatic acini with Paneth cell-like change.

[Pathological and immunohistochemical analyses of 32 cases of nephrogenic adenoma]

OBJECTIVE

To observe clinical and pathological features of nephrogenic adenoma (NA), and to find some useful immunohistochemical markers for its diagnosis.

METHODS

The clinical features of 32 NA patients were obtained. Each case underwent microscopic observation and immumohistochemical staining. The primary antibodies were α-methylacyl-CoA racemase (AMACR, P504S), cytokeratin AE1/AE3, cytokeratin 7 (CK7), cytokeratin 20 (CK20), paired-box 2 (PAX2), paired-box 8 (PAX8), vimentin, membrane metallo-endopeptidase (MME, CD10), prostate specific antigen (PSA), high molecular weight cytokeratin (34βE12), P63 and carcinoembryonic antigen (CEA).

RESULTS

NA mainly involved old men, and the bladder was the commonest location. The macroscopic features were prevalently small polypoid or papillary lesions, ranging from 1 mm to 10 mm (mean=4). The typical histological features included tubular, tubulocystic, polypoid and/or papillary. Immunohistochemistry for NA was positive for AMACR, AE1/AE3, PAX2, PAX8, CK7, vimentin and CD10. The negative immunostain for NA included P63, PSA and CEA.

CONCLUSION

NA is a rare and easily misdiagnosed lesion. Careful histological examination is essential to accurately identify this lesion. A panel composed of AMACR (P504S), PAX8/PAX2, CK7, P63, PSA and CEA appears to be sensitive and specific in differentiating NA from its mimics of urothelial and prostatic origins.

Identification of unknown protein function using metabolite cocktail screening

Proteins of unknown function comprise a significant fraction of sequenced genomes. Defining the roles of these proteins is vital to understanding cellular processes. Here, we describe a method to determine a protein function based on the identification of its natural ligand(s) by the crystallographic screening of the binding of a metabolite library, followed by a focused search in the metabolic space. The method was applied to two protein families with unknown function, PF01256 and YjeF_N. The PF01256 proteins, represented by YxkO from Bacillus subtilis and the C-terminal domain of Tm0922 from Thermotoga maritima, were shown to catalyze ADP/ATP-dependent NAD(P)H-hydrate dehydratation, a previously described orphan activity. The YjeF_N proteins, represented by mouse apolipoprotein A-I binding protein and the N-terminal domain of Tm0922, were found to interact with an adenosine diphosphoribose-related substrate and likely serve as ADP-ribosyltransferases. Crystallographic screening of metabolites serves as an efficient tool in functional analyses of uncharacterized proteins.

Biochemical and structural characterization of apolipoprotein A-I binding protein, a novel phosphoprotein with a potential role in sperm capacitation

The physiological changes that sperm undergo in the female reproductive tract rendering them fertilization-competent constitute the phenomenon of capacitation. Cholesterol efflux from the sperm surface and protein kinase A (PKA)-dependent phosphorylation play major regulatory roles in capacitation, but the link between these two phenomena is unknown. We report that apolipoprotein A-I binding protein (AI-BP) is phosphorylated downstream to PKA activation, localizes to both sperm head and tail domains, and is released from the sperm into the media during in vitro capacitation. AI-BP interacts with apolipoprotein A-I, the component of high-density lipoprotein involved in cholesterol transport. The crystal structure demonstrates that the subunit of the AI-BP homodimer has a Rossmann-like fold. The protein surface has a large two compartment cavity lined with conserved residues. This cavity is likely to constitute an active site, suggesting that AI-BP functions as an enzyme. The presence of AI-BP in sperm, its phosphorylation by PKA, and its release during capacitation suggest that AI-BP plays an important role in capacitation possibly providing a link between protein phosphorylation and cholesterol efflux.

Racemization at C-2 of naringin in sour oranges with increasing maturity determined by chiral high-performance liquid chromatography

Naringin is the major flavanone-7-O-glycoside of sour orange, and it is mainly responsible for the bitter taste of the fruit. The relative content of (2S)- and (2R)-naringin in the albedo of sour oranges during maturation in the entire season was determined by normal phase HPLC using Chiralcel OD-H as chiral stationary phase and n-hexane/ethanol doped with 0.5% of TFA as mobile phase. HPLC traces were complicated by the presence of (2S)-neohesperidin, and a software-guided analysis was developed to assess the relative amount of the C-2 diastereomers of naringin. A sigmoid curve was obtained showing variation from 94% of (2S)-naringin in very immature fruits to 69.7% in mature fruit samples. Spontaneous epimerization of (2S)-naringin in the ethanolic solutions of the albedo was noted after prolonged keeping for less acid samples. The separation of the C-2 diastereomers of other flavanoid-7-O-glycosides present in Citrus (neoeriocitrin, neohesperidin, and eriocitrin) was also obtained by chiral HPLC and afforded the identification, including stereochemistry, of the eluting peaks in the HPLC traces of the albedo extracts.

ApoA-I-binding protein (AI-BP) and its homologues hYjeF_N2 and hYjeF_N3 comprise the YjeF_N domain protein family in humans with a role in spermiogenesis and oogenesis

The screening for additional human YjeF_N domain containing proteins beside the apolipoprotein A-I interacting protein (AI-BP), identified two other genes designated hYjeF_N2-15q23 (formerly human homologue of yeast edc3) and hYjeF_N3-19p13.11 comprising the human YjeF_N family. AI-BP is ubiquitously expressed, with a predominance of these tissues where the homologues were found to be restricted including brain, mammary gland, testes and ovaries. Immunohistochemistry of human testes and ovaries showed an expression of hYjeF_N3-19p13.11 only in Leydig cells and theca cells, respectively, indicating a role in steroid hormone metabolism. Interestingly, the protein was also strongly expressed in Leydig cell tumors and in thecofibromas. The identification of hYjeF_N2-15q23 in theca cells and granulosa cells in ovaries, in human spermatids of meiotic division part II and the apical membrane of Sertoli cells in testes suggest similar functions in oogenesis and sperm maturation which is strengthened by the identification of the spermatogenesis regulator HMGA1 as a conserved transcription factor. However, in contrast to AI-BP, both homologous proteins are unable to bind apoA-I. These results relate the human YjeF_N domain containing protein family to cholesterol processing and steroid hormone metabolism in spermiogenesis and oogenesis, and AI-BP may link this function to the HDL pathway.

[Intravenous S-+-ketamine for treatment of visceral pain in the final phase]

Ketamine is a hypnotic pharmacon with high analgesic potency. Ketamine is an agent blocking NMDA-receptors and involves opioid receptors, the voltage-gated sodium-channel, cholinergic receptors and the monoaminergic descending inhibitory pathways. Besides its influence in chronification of pain, NMDA-R is crucial in induction and maintainance of visceral pain, attentional perceptual processes and emotional valuation of pain. The analgesic potency of S-+-Ketamine doubles racemic Ketamine's analgesic potency. Thus the incidence of CNS-side effects ought to be reduced to 50% in equianalgesic dosages. Evidence supports the assumption that continuous infusion of S-+-Ketamine 2.5-5 mg/hour is effective in treating visceral pain of high intensity. In the presence of chronic pain states the effect ought to be more marked. There is evidence that the probability of psychotomimetic side effects does not exceed 10%. The rate of side effects can further be minimized through careful titration and prophylaxis (or treatment) with Diazepam 1 mg i.v.

Diagnostic utility of a p63/alpha-methyl coenzyme A racemase (p504s) cocktail in ambiguous lesions of the prostate upon needle biopsy

OBJECTIVE

To investigate the potential utility of a new combined immunostaining technique for diagnosing prostate cancer from histological analysis of needle biopsy specimens.

MATERIALS AND METHODS

Tissue was immunostained with a combination of antibodies against a basal cell marker (p63), and an enzyme commonly overexpressed in prostate cancer (p504s), on 63 small prostate cancer foci (<1 mm) and 109 cases of ambiguous lesions observed in needle biopsies.

RESULTS

After p63/p504s immunostaining, 93% of the ambiguous lesions (102/109) were classified. The final diagnoses retained were: 92 prostate cancers, seven atypical small acinar proliferations suspected of being malignant but undiagnosed, 21 prostatic intraepithelial neoplasia, five atypical adenomatous hyperplasia, and 36 atrophic benign mimickers of cancer.

CONCLUSIONS

Combining p504s as a positive marker for prostate cancer and p63 as a negative marker might improve diagnostic performance, sensitivity and specificity, and lead to fewer false-negative results. This simple immunostaining procedure should reduce the percentage of residual ambiguous lesions and the need for additional biopsies.

Serotonin synthesis inhibition reveals distinct mechanisms of action for MDMA and its enantiomers in the mouse

RATIONALE

Drug challenges in "intact" and p-chlorophenylalanine (p-CPA)-treated animals can be used to distinguish agents that act as direct serotonin (5-HT) agonists from agents that function as 5-HT releasers.

OBJECTIVES

The objective of the study was to investigate the effect of p-CPA treatment on the capacity of racemic 3,4-methylenedioxymethamphetamine (MDMA) and its stereoisomers to induce the head twitch response, hyperthermia, and locomotor stimulation in mice.

METHODS

Pretreatments with either 100 mg/kg p-CPA or equivolume saline were administered for three consecutive days. The following day, mice were either euthanized (to quantify 5-HT tone), tested with various doses of racemic MDMA or one of its enantiomers in the head twitch assay, or challenged with 32 mg/kg racemic MDMA or one of its enantiomers, while temperature and locomotor activity were monitored via radiotelemetry.

RESULTS

p-CPA reduced cortical 5-HT turnover by >70% without altering dopamine turnover. Racemic MDMA did not induce a significant head twitch response in intact or p-CPA-treated mice. S(+)-MDMA and R(-)-MDMA elicited similar head twitch curves in intact mice; p-CPA treatment attenuated this response when induced by S(+)-MDMA but not when elicited by R(-)-MDMA. Neither the hyperthermic nor locomotor-stimulant effects of racemic MDMA were altered by p-CPA treatment. The hyperthermic effects, but not the locomotor-stimulant effects, of S(+)-MDMA were attenuated in mice treated with p-CPA. R(-)-MDMA did not alter core temperature or induce significant locomotor stimulation in intact or p-CPA-treated mice.

CONCLUSIONS

The effects of S(+)-MDMA on core temperature and head twitch behavior are consistent with a mechanism involving 5-HT release, whereas the effects of R(-)-MDMA on head twitch behavior are consistent with a direct agonist mechanism of action. The actions of the racemate on core temperature and locomotor activity likely involve a combination of 5-HT release and direct agonism at 5-HT receptors.

Differential effects of amphetamine isomers on dopamine release in the rat striatum and nucleus accumbens core

RATIONALE

Current medications for attention-deficit/hyperactivity disorder (ADHD) include some single isomer compounds [dextroamphetamine (D: -amphetamine, dexedrine) and dexmethylphenidate (Focalin)] and some racemic compounds [methylphenidate and mixed-salts amphetamine (Adderall)]. Adderall, which contains approximately 25% L: -amphetamine, has been successfully marketed as a first-line medication for ADHD. Although different clinical effects have been observed for D: -amphetamine, Adderall, and benzedrine; potential psychopharmacological differences on the level of neurotransmission between D: -amphetamine and L: -amphetamine have not been well characterized.

OBJECTIVES

To evaluate potential differences in the isomers, we used the technique of high-speed chronoamperometry with Nafion-coated single carbon-fiber microelectrodes to measure amphetamine-induced release of dopamine (DA) in the striatum and nucleus accumbens core of anesthetized male Fischer 344 rats. Amphetamine solutions were locally applied by pressure ejection using micropipettes.

RESULTS

The presence of L: -amphetamine in the D: ,L: -amphetamine solutions did not cause increased release of DA but did change DA release kinetics. The D: ,L: -amphetamine-evoked signals exhibited significantly faster rise times and shorter signal decay times. This difference was also observed in the nucleus accumbens core. When L: -amphetamine was locally applied, DA release was not significantly different in amplitude, and it exhibited the same rapid kinetics of D: ,L: -amphetamine.

CONCLUSIONS

These data support the hypothesis that amphetamine isomers have different effects on release of DA from nerve endings. It is possible that L: -amphetamine may have unique actions on the DA transporter, which is required for the effects of amphetamine on DA release from nerve terminals.

Utility of immunohistochemistry for alpha-methylacyl-CoA racemase in distinguishing atrophic prostate cancer from benign atrophy

Small atrophic prostate cancers on needle biopsy are rare and difficult to distinguish from benign atrophy on needle biopsy. We report on a study of 23 needle biopsy specimens with small foci of atrophic prostate cancer from the consult service of one of the authors. In 19 cancer cases the atrophic component was pure; in 4 cases it was dominant with a minor (<5%) nonatrophic cancer component. These atrophic cancers and 16 cases of florid benign atrophy on needle biopsy were examined by immunohistochemistry for alpha-methylacyl-CoA-racemase (AMACR). All cases of cancer and atrophy were verified immunohistochemically with antibodies to basal cells (34betaE12 and p63). AMACR staining were scored as 1+ (5% to 25% of glands expressing AMACR), 2+ (26% to 50% of glands expressing AMACR), or 3+ (>50% of glands expressing AMACR). Positive staining was defined as staining above that of surrounding benign glands. AMACR was expressed in 69.6% of atrophic prostate cancers (3+, 11 cases; 2+, 3 cases; 1+, 2 cases); 30.4% (7 cases) of atrophic prostate cancer exhibited no AMACR expression. In the 4 cases with a few glands of ordinary (nonatrophic) prostate cancer, the nonatrophic cancer demonstrated more intense and a greater extent of AMACR staining. Fourteen cases (87.5%) of benign atrophy showed no AMACR expression. In 2 cases (12.5%) of benign atrophy, background immunostaining made it difficult to assess AMACR expression. We conclude that AMACR immunostaining alone is not sufficiently discriminatory in the differential diagnosis of atrophic prostate cancer versus benign atrophy. Atrophic prostate cancers are not as frequently or as strongly positive as ordinary prostate cancer. Using a panel of immunostains including AMACR, 34betaE12 and p63 (positive AMACR immunostaining along with negative basal cell markers) is recommended in the differentiation of atrophic prostate cancer and benign atrophy.

Prostate cancer detection on urinalysis for alpha methylacyl coenzyme a racemase protein

PURPOSE

We assessed the feasibility of a novel urinary test for prostate cancer based on the presence of alpha methylacyl coenzyme A racemase (AMACR) protein in voided urine specimens obtained after prostate biopsy.

MATERIALS AND METHODS

Clean catch voided urine specimens were prospectively collected from 26 consecutive men immediately after transrectal ultrasound guided prostate biopsy for suspected malignancy. The presence of AMACR was evaluated in a blinded manner by Western blot analysis and correlated with biopsy results and patient clinical information.

RESULTS

AMACR was detected in the urine in 18 of 26 patients (69%). AMACR was detected in all 12 patients with biopsy confirmed adenocarcinoma of the prostate (100% sensitivity, 95% CI 75 to 100), in 5 of 12 with no evidence of cancer on biopsy (58% specificity, 95% CI 29 to 78) and in 1 of 2 (50%, 95% CI 3 to 80) with atypia on biopsy. Overall AMACR detection was associated with cancer status by prostate biopsy in 21 of 26 patients (86%).

CONCLUSIONS

We report the feasibility of a novel, noninvasive, nonprostate specific antigen based molecular approach to detect prostate cancer in voided urine. To our knowledge this is the first report of AMACR protein detection in the urine of patients with prostate cancer. A screening test based on urinary AMACR may develop into a useful adjunct to serum prostate specific antigen and digital rectal examination for identifying men at increased risk for harboring prostate cancer despite negative biopsy. Such a test has potential application for stratifying patients into low and high risk groups for surveillance vs repeat biopsy.

The N-methyl D-aspartate receptor glycine site and D-serine metabolism: an evolutionary perspective

The N-methyl D-aspartate (NMDA) type of glutamate receptor requires two distinct agonists to operate. Glycine is assumed to be the endogenous ligand for the NMDA receptor glycine site, but this notion has been challenged by the discovery of high levels of endogenous d-serine in the mammalian forebrain. I have outlined an evolutionary framework for the appearance of a glycine site in animals and the metabolic events leading to high levels of D-serine in brain. Sequence alignments of the glycine-binding regions, along with the scant experimental data available, suggest that the properties of invertebrate NMDA receptor glycine sites are probably different from those in vertebrates. The synthesis of D-serine in brain is due to a pyridoxal-5'-phosphate (B(6))-requiring serine racemase in glia. Although it remains unknown when serine racemase first evolved, data concerning the evolution of B(6) enzymes, along with the known occurrences of serine racemases in animals, point to D-serine synthesis arising around the divergence time of arthropods. D-Serine catabolism occurs via the ancient peroxisomal enzyme d-amino acid oxidase (DAO), whose ontogenetic expression in the hindbrain of mammals is delayed until the postnatal period and absent from the forebrain. The phylogeny of D-serine metabolism has relevance to our understanding of brain ontogeny, schizophrenia and neurotransmitter dynamics.

Expression of desmosomal proteins in squamous cell carcinomas of the skin

BACKGROUND

Desmosomal proteins are well established markers of epithelial differentiation. Down-regulation of desmosomal proteins has been suggested to be a sign of reduced adhesiveness in metastasizing cells.

METHODS

We examined actinic keratoses, Bowen's disease, and squamous cell carcinoma (SCC) of the skin for the expression of desmosomal proteins using isoform-specific antibodies on paraffin-embedded sections. Evaluation was performed qualitatively in comparison to the epidermis and semiquantitatively using an area-intensity-score.

RESULTS

We found no qualitative correlation of desmoplakin or plakoglobin expression with risk of metastasis. Plakophilin 1, desmoglein 1, and the desmocollins 1-3 were found to be heterogeneously expressed in all neoplasms without significant correlation to aggressive tumor behavior. Plakophilin 2 was not expressed in any of the neoplasms examined. As most striking finding, desmoglein 2 was up-regulated qualitatively in half of all neoplasms examined and showed a significant higher proportion of positive cells in high-risk SCC than in low-risk SCC.

CONCLUSIONS

Desmosomal proteins are highly regulated in cutaneous SCC. Only desmoglein 2 expression correlates with risk of metastasis. Desmosomes may still be functional in metastasizing tumor cells.