Microneedle patch for the ultrasensitive quantification of protein biomarkers in interstitial fluid

The detection and quantification of protein biomarkers in interstitial fluid is hampered by challenges in its sampling and analysis. Here we report the use of a microneedle patch for fast in vivo sampling and on-needle quantification of target protein biomarkers in interstitial fluid. We used plasmonic fluor-an ultrabright fluorescent label-to improve the limit of detection of various interstitial fluid protein biomarkers by nearly 800-fold compared with conventional fluorophores, and a magnetic backing layer to implement conventional immunoassay procedures on the patch and thus improve measurement consistency. We used the microneedle patch in mice for minimally invasive evaluation of the efficiency of a cocaine vaccine, for longitudinal monitoring of the levels of inflammatory biomarkers, and for efficient sampling of the calvarial periosteum-a challenging site for biomarker detection-and the quantification of its levels of the matricellular protein periostin, which cannot be accurately inferred from blood or other systemic biofluids. Microneedle patches for the minimally invasive collection and analysis of biomarkers in interstitial fluid might facilitate point-of-care diagnostics and longitudinal monitoring.

Location of an inducible nitric oxide synthase mRNA in the normal kidney

An inducible nitric oxide synthase (iNOS) mRNA was found primarily in the outer medulla of normal rat kidney. Identification of the mRNA was based upon the specificity of the oligonucleotide primers used for PCR amplification, PCR-Southern blot analysis and the nucleic acid sequence of the cloned PCR product. In addition to the outer medulla, glomeruli prepared from normal rat kidney contained significant amounts of an iNOS mRNA. These results suggest that there may be tonic influences in the outer medulla of the normal rat kidney resulting in the "steady-state" presence of an iNOS mRNA. Cortical tubules and the inner medulla were found to contain detectable but lesser amounts of the iNOS mRNA. The outer medulla was microdissected into proximal straight tubule (PST), medullary thick ascending limb (MTAL), medullary collecting duct (MCD) and vasa recta bundle (VRB). The iNOS mRNA was found primarily in the MTAL with minor amounts in the MCD and VRB of normal rat kidney. Animals were injected with lipopolysaccharide (LPS) and sacrificed 24 hours later. Treatment with LPS caused at least a 20-fold increase in the amount of iNOS mRNA in the liver or in macrophages isolated from the peritoneum. Endotoxin treatment led to over a 10-fold increase in iNOS mRNA content in glomeruli and the inner medulla. The iNOS mRNA level of the outer medulla was increased two- to threefold due to LPS treatment.

Phenobarbital induction of cytochromes P-450. High-level long-term responsiveness of primary rat hepatocyte cultures to drug induction, and glucocorticoid dependence of the phenobarbital response

The induction of hepatic cytochromes P-450 by phenobarbital (PB) was studied in rat hepatocytes cultured for up to 5 weeks on Vitrogen-coated plates in serum-free modified Chee's medium then exposed to PB (0.75 mM) for an additional 4 days. Immunoblotting analysis indicated that P-450 forms PB4 (IIB1) and PB5 (IIB2) were induced dramatically (greater than 50-fold increase), up to levels nearly as high as those achieved in PB-induced rat liver in vivo. The newly synthesized cytochrome P-450 was enzymically active, as shown by the major induction of the P-450 PB4-dependent steroid 16 beta-hydroxylase and pentoxyresorufin O-dealkylase activities in the PB-induced hepatocyte microsomes (up to 90-fold increase). PB induction of these P-450s was markedly enhanced by the presence of dexamethasone (50 nM-1 microM), which alone was not an affective inducing agent, and was inhibited by greater than 90% by 10% fetal bovine serum. The PB response was also inhibited (greater than 85%) by growth hormone (250 ng/ml), indicating that this hormone probably acts directly on the hepatocyte when it antagonizes the induction of P-450 PB4 in intact rats. In untreated hepatocytes, P-450 RLM2 (IIA2), P-450 3 (IIA1) and NADPH P-450 reductase levels were substantially maintained in the cultures for 10-20 days. The latter two enzymes were also inducible by PB to an extent (3-4 fold elevation) that is comparable with that observed in the liver in vivo. Moreover, P-450c (IA1) and P-450 3 (IIA1) were highly inducible by 3-methylcholanthrene (5 microM; 48 h exposure) even after 3 weeks in culture. In contrast, the male-specific pituitary-regulated P-450 form 2c (IIC11) was rapidly lost upon culturing the hepatocytes, suggesting that supplementation of appropriate hormonal factors may be necessary for its expression. The present hepatocyte culture system exhibits a responsiveness to drug inducers that is qualitatively and quantitatively comparable with that observed in vivo, and should prove valuable for more detailed investigations of the molecular and mechanistic basis of the response to PB and its modulation by endogenous hormones.

Nitric oxide generation ameliorates the tubulointerstitial fibrosis of obstructive nephropathy

Angiotensin-converting enzyme (ACE) inhibitors have been shown to minimize fibrosis of the kidney tubulointerstitium in several diseases. In addition to lowering angiotensin II levels, ACE inhibitors can increase kinin levels and subsequently increase nitric oxide formation. To determine whether nitric oxide generation is a component of the beneficial effect of ACE inhibitors on renal fibrosis, enalapril, enalapril plus NG-nitro-L-arginine methyl ester (L-NAME) or L-arginine was administered to rats that had undergone unilateral ureteral obstruction (UUO). Ureteral obstruction caused significant increases in interstitial volume, monocyte macrophage infiltration, interstitial collagen IV and alpha-smooth muscle actin expression, transforming growth factor-beta 1 mRNA, collagen IV mRNA, and tissue inhibitor of metalloproteinase-1 mRNA. Enalapril treatment significantly blunted the increase in all parameters during UUO. Cotreatment of the animals with enalapril and L-NAME reversed the beneficial effect of enalapril in the obstructed kidney for all parameters. Treatment of animals with UUO with L-arginine significantly blunted the increase in all parameters except for transforming growth factor-beta 1 mRNA expression. In the enalapril- plus-L-NAME-treated animals, there were modest but significant increases in monocyte/macrophage infiltration of the interstitium and glomerulus, and collagen IV and alpha-smooth muscle actin expression in the interstitium of the contralateral unobstructed kidney. The urine nitrite concentration was significantly increased by either enalapril or L-arginine treatment, whereas L-NAME significantly reduced urine nitrite concentration. These results suggest that treatment modalities that increase nitric oxide formation have a beneficial effect on the progression of cellular and molecular parameters of tubulointerstitial fibrosis caused by obstruction of the ureter.

Ultrabright fluorescent nanoscale labels for the femtomolar detection of analytes with standard bioassays

The detection and quantification of low-abundance molecular biomarkers in biological samples is challenging. Here, we show that a plasmonic nanoscale construct serving as an ‘add-on’ label for a broad range of bioassays improves their signal-to-noise ratio and dynamic range without altering their workflow and read-out devices. The plasmonic construct consists of a bovine-serum-albumin scaffold with approximately 210 IRDye 800CW fluorophores (with fluorescence intensity approximately 6700-fold that of a single 800CW fluorophore), a polymer-coated gold nanorod acting as a plasmonic antenna, and biotin as a high-affinity biorecognition element. Its emission wavelength can be tuned over the visible and near-infrared spectral regions by modifying its size, shape and composition. It is compatible with multiplexed bead-based immunoassays (it improves the limit of detection by up to 4,750-fold in fluorescence-linked immunosorbent assays), immuno-microarrays, flow-cytometry and immunocytochemistry methods, and it shortens overall assay times and lowers sample volumes, as shown for the detection of a pro-inflammatory cytokine in mouse interstitial fluid and of urinary biomarkers in patient samples.

Rapid communication. Enalapril decreases nuclear factor kappa B activation in the kidney with ureteral obstruction

The transcription factor nuclear factor kappa B (NF-kappa B) controls a number of genes associated with tissue inflammation and has been shown to be activated in the kidney with ureteral obstruction. In this investigation, we further explored NF-kappa B activation in the kidney cortex of rats with unilateral ureteral obstruction. Electrophoretic mobility shift assays combined with antibody supershift/depletion demonstrated that NF-kappa B subunits p50, p52, c-rel, p65 (RelA) and RelB were all activated. Immunocytochemical analysis using an antibody to the p50 subunit demonstrated activation occurring predominantly in nuclei of tubular cells. Treatment of animals with unilateral ureteral obstruction with an oral ACE inhibitor significantly decreased NF-kappa B activation. This suggests that the antiinflammatory effect of ACE inhibitors in renal disease is in part due to a blunting of NF-kappa B activation.

Bioplasmonic paper as a platform for detection of kidney cancer biomarkers

We demonstrate that a common laboratory filter paper uniformly adsorbed with biofunctionalized plasmonic nanostructures can serve as a highly sensitive transduction platform for rapid detection of trace bioanalytes in physiological fluids. In particular, we demonstrate that bioplasmonic paper enables rapid urinalysis for the detection of kidney cancer biomarkers in artificial urine down to a concentration of 10 ng/mL. Compared to conventional rigid substrates, bioplasmonic paper offers numerous advantages such as high specific surface area (resulting in large dynamic range), excellent wicking properties (naturally microfluidic), mechanical flexibility, compatibility with conventional printing approaches (enabling multiplexed detection and multimarker biochips), and significant cost reduction.

Female-predominant rat hepatic P-450 forms j (IIE1) and 3 (IIA1) are under hormonal regulatory controls distinct from those of the sex-specific P-450 forms

Hepatic expression of cytochrome P-450j (alcohol-inducible nitrosamine demethylase; P-450 gene IIE1) and P-450 3 (testosterone 7 alpha-hydroxylase; P-450 gene IIA1) is female predominant in adult rats [female/male greater than or equal to 1.5-2 (P-450j) or 3-4 (P-450 3)]. This sex difference emerges during the postsuckling period, when P-450 3 declines significantly (60-70% decrease) in male, but not female, rats, and P-450j declines in both sexes, but to a lower constitutive level in males than in females. The biochemical factors and regulatory events that control these developmental changes were investigated and found to be distinct from those that regulate expression of the female-specific hepatic enzymes P-450 2d (P-450 gene IIC12) and steroid 5 alpha-reductase. Immunoquantitation of the changes in P-450j and P-450 3 levels in hormonally altered rats established that both P-450s are under gonadal control. However, while androgen and estrogen both suppress P-450j expression, estrogen stimulates and androgen suppresses the expression of P-450 3. Since many of the effects of gonadal hormones on hepatic enzyme levels are mediated by the pituitary, the contribution of pituitary hormones to P-450j and P-450 3 expression was evaluated. Hypophysectomy of adult rats of either sex elevated P-450j to the levels found in immature rats (3- to 5-fold increase). This elevation was largely reversed in both sexes by GH administered either intermittently or continuously, demonstrating that P-450j is under the suppressive control of this pituitary hormone. The regulation of P-450 3 was more complex. Hypophysectomy elevated P-450 3 to prepubertal levels in adult male rats, but had no effect on P-450 3 levels in adult females. In both sexes GH suppressed P-450 3 expression when administered to hypophysectomized rats intermittently, but stimulated P-450 3 expression when infused continuously. Corresponding changes in hepatic microsomal P-450 3-dependent testosterone 7 alpha-hydroxylase and P-450j-dependent aniline hydroxylase activities were observed in response to hypophysectomy and GH replacement, but only after supplementation of microsomal NADPH P-450 reductase [which was 63-77% suppressed by hypophysectomy] with exogenous purified NADPH P-450 reductase. These studies demonstrate that these female-predominant hepatic P-450 enzymes are regulated by different mechanisms, and that both are under hormonal regulatory controls distinct from those that govern expression of the female-specific hepatic enzymes.(ABSTRACT TRUNCATED AT 400 WORDS)

Evaluation of Urine Aquaporin-1 and Perilipin-2 Concentrations as Biomarkers to Screen for Renal Cell Carcinoma: A Prospective Cohort Study

IMPORTANCE

Historically, early detection of small asymptomatic kidney tumors presages better patient outcome. Screening for asymptomatic renal tumors by abdominal imaging is not cost-effective and cannot reliably distinguish benign from malignant tumors.

OBJECTIVE

This investigation evaluated the clinical utility, sensitivity, and specificity of urine aquaporin-1 (AQP1) and perilipin-2 (PLIN2) concentrations as unique, noninvasive biomarkers to diagnose malignant clear cell or papillary renal cell carcinoma (RCC) in a screening paradigm.

DESIGN, SETTING, AND PARTICIPANTS

From February through December 2012, urine samples were obtained from 720 patients undergoing routine abdominal computed tomography (CT) (screening population), 80 healthy controls, and 19 patients with pathologically confirmed RCC.

MAIN OUTCOMES AND MEASURES

Urine AQP1 and PLIN2 concentrations were measured by sensitive and specific enzyme-linked immunosorbent assay and Western blot procedures, respectively, in all groups. In the otherwise asymptomatic screening population, the absence or presence of a renal mass and RCC were verified by abdominal CT and by postnephrectomy pathologic diagnosis, respectively.

RESULTS

Urine AQP1 and PLIN2 concentrations were significantly higher (all P < .001) in the 19 patients with known RCC (AQP1 median [95% CI], 225.0 [121.0-450.0] ng/mg urine creatinine; and PLIN2 median [95% CI], 37.8 [22.8-83.7] absorbance units/mg creatinine) than in the 80 healthy controls (AQP1 median [95% CI], 1.1 [0.9-1.3] ng/mg urine creatinine; and PLIN2 median [95% CI], 3.1 [2.4-3.7] absorbance units/mg creatinine) and the 720 patient screening population (AQP1 median [95% CI], 0.5 [0.0-1.0] ng/mg urine creatinine; and PLIN2 median [95% CI], 0 [0-0] absorbance units/mg creatinine). The area under the receiver operating characteristic curve for urine AQP1 and PLIN2 concentrations individually or in combination was 0.990 or greater, with 95% or greater sensitivity and 91% or greater specificity compared with controls or the screening population. Of the 720 screened patients, 3 had biomarker concentrations suggestive of RCC and were found to have an imaged renal mass by CT. Two of the patients had pathologically confirmed RCC in further evaluation.

CONCLUSIONS AND RELEVANCE

These results demonstrate the clinical utility, specificity, and sensitivity of urine AQP1 and PLIN2 to diagnose RCC. These tumor-specific proteins have high clinical validity and substantial potential as specific diagnostic and screening biomarkers for clear cell or papillary RCC and in the differential diagnosis of imaged renal masses.

Pituitary regulation of the male-specific steroid 6 beta-hydroxylase P-450 2a (gene product IIIA2) in adult rat liver. Suppressive influence of growth hormone and thyroxine acting at a pretranslational leve;

Oligonucleotide probes that distinguish between two closely related mRNAs encoding steroid 6 beta-hydroxylases of rat P-450 gene family CYP3A were used to individually assess their responsiveness to pituitary hormone regulation. Northern blot analysis revealed that the elevation of immunoreactive P-450 IIIA2 in livers of hypophysectomized rats reflects an elevation of the constitutive, male-specific P-450 IIIA2 (P-450 2a) and not an induction of the drug-inducible P-450 IIIA1 (P-450p). P-450 IIIA2 mRNA levels in intact adult male rats were found to be markedly reduced by GH administered as a continuous infusion at levels as low as 1 mU/h, indicating that GH acts at a pretranslational step to suppress expression of this P-450 enzyme. In hypophysectomized male rats, however, this same hormone treatment was only partially effective at suppressing P-450 IIIA2 mRNA and protein, suggesting that other pituitary-dependent factors contribute to the suppression observed in the intact rats. Further analysis revealed that T4, but not ACTH or human CG, can act in concert with GH to effect a more complete suppression of hepatic P-450 IIIA2 mRNA and protein in hypophysectomized rats. T4 also suppressed the expression of another GH-regulated, male-specific hepatic enzyme, designated P-450 IIA2 (P-450 RLM2), particularly in hypophysectomized female rats. In contrast, the GH-responsive P-450 IIA1 (P-450 3) was much less affected by T4 treatment. Thus, while T4 can modulate P-450 IIIA2 expression, it does not serve as a universal regulator for hepatic expression of GH-responsive P-450s.

Hot Spot-Localized Artificial Antibodies for Label-Free Plasmonic Biosensing

The development of biomolecular imprinting over the last decade has raised promising perspectives in replacing natural antibodies with artificial antibodies. A significant number of reports have been dedicated to imprinting of organic and inorganic nanostructures, but very few were performed on nanomaterials with a transduction function. Herein we describe a relatively fast and efficient plasmonic hot spot-localized surface imprinting of gold nanorods using reversible template immobilization and siloxane co-polymerization. The technique enables a fine control of the imprinting process at the nanometer scale and provides a nanobiosensor with high selectivity and reusability. Proof of concept is established by the detection of neutrophil gelatinase-associated lipocalin (NGAL), a biomarker for acute kidney injury, using localized surface plasmon resonance spectroscopy. The work represents a valuable step towards plasmonic nanobiosensors with synthetic antibodies for label-free and cost-efficient diagnostic assays. We expect that this novel class of surface imprinted plasmonic nanomaterials will open up new possibilities in advancing biomedical applications of plasmonic nanostructures.

Urinary biomarkers for the early diagnosis of kidney cancer

OBJECTIVE

To test the hypothesis that increased tumor expression of proteins such as aquaporin-1 (AQP1) and adipophilin (ADFP) in patients with renal cancer would result in increased urine AQP1 and ADFP excretion.

PATIENTS AND METHODS

Prenephrectomy and postnephrectomy (pseudocontrol) urine samples were collected from 42 patients with an incidental radiographically discovered renal mass and presurgical presumptive diagnosis of kidney cancer from July 8, 2008, through March 10, 2009. Also enrolled were 15 control patients who underwent nonrenal surgery and 19 healthy volunteers. Urine AQP1 and ADFP concentrations normalized to urine creatinine were determined by sensitive and specific Western blot assays.

RESULTS

Mean +/- SD preexcision urine AQP1 and ADFP concentrations (76+/-29 and 117+/-74 arbitrary units, respectively) in patients with a pathologic diagnosis of clear cell (n=22) or papillary (n=10) cancer were significantly greater than in patients with renal cancer of nonproximal tubule origin, control surgical patients, and healthy volunteers (combined values of 0.1+/-0.1 and 1.0+/-1.6 arbitrary units, respectively; n=44; P<.001). The AQP1 and ADFP concentrations decreased 88% to 97% in the 25 patients with clear cell or papillary cancer who provided postnephrectomy follow-up urine samples. In patients with clear cell and papillary carcinoma, a linear correlation (Spearman) was found between tumor size and preexcision urine AQP1 or ADFP concentration (r=0.82 and 0.76, respectively; P<.001 for each).

CONCLUSION

Urine AQP1 and ADFP concentrations appear to be sensitive and specific biomarkers of kidney cancers of proximal tubule origin. These biomarkers may be useful to diagnose an imaged renal mass and screen for kidney cancer at an early stage.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00851994.

The effects of calcium and magnesium on the secretion of parathormone and parathyroid secretory protein by isolated porcine parathyroid cells

The preparation of dispersed parathyroid cells by collagenase digestion of porcine parathyroid glands, essentially as outlined by Brown et al. (Endocrinology 99: 1582, 1976), is described. The cells secrete parathormone linearly for at least 4 h of incubation and rapidly respond in inverse fashion to changes in the medium calcium and magnesium concentrations over the range 0.5-3.0 mM. In terms of inhibition of secretion, either ion was more effective in the presence of a minimum concentration of the other, indicating that calcium and magnesium affect separate cellular sites. Parathormone was identified both by immunoassay of the whole incubation medium and by its separation by polyacrylamide gels and carboxymethylcellulose chromatography. When the cells were incubated with radioactive amino acids and both the medium and cells were subsequently analyzed on gels, we found that parathyroid secretory protein as well as parathormone and some immunoactive fragments were present. Analysis of the radioactive protein contained in the cells at high and low calcium concentrations revealed that calcium decreased the formation of the secretory protein by approximately 40% without appreciably affecting the formation of proparathormone or parathormone. The secretion of both parathyroid secretory protein and parathormone were inversely proportional to the concentrations of medium calcium or magnesium. The secretion of the latter, however, was more sensitive (95% inhibition) than parathormone (40-60% inhibition) to changes in medium divalent cations. These results suggest that the synthesis, intracellular processing, or secretion of parathormone and parathyroid secretory protein utilize independent calcium- and magnesium-regulated pathways.

Peptide Functionalized Gold Nanorods for the Sensitive Detection of a Cardiac Biomarker Using Plasmonic Paper Devices

The sensitivity of localized surface plasmon resonance (LSPR) of metal nanostructures to adsorbates lends itself to a powerful class of label-free biosensors. Optical properties of plasmonic nanostructures are dependent on the geometrical features and the local dielectric environment. The exponential decay of the sensitivity from the surface of the plasmonic nanotransducer calls for the careful consideration in its design with particular attention to the size of the recognition and analyte layers. In this study, we demonstrate that short peptides as biorecognition elements (BRE) compared to larger antibodies as target capture agents offer several advantages. Using a bioplasmonic paper device (BPD), we demonstrate the selective and sensitive detection of the cardiac biomarker troponin I (cTnI). The smaller sized peptide provides higher sensitivity and a lower detection limit using a BPD. Furthermore, the excellent shelf-life and thermal stability of peptide-based LSPR sensors, which precludes the need for special storage conditions, makes it ideal for use in resource-limited settings.

Secretion and degradation of parathormone as a function of intracellular maturation of hormone pools. Modulation by calcium and dibutyryl cyclic AMP

The biosynthesis, processing, and secretion of parthormone and the effect of calcium on these processes were measured in dispersed porcine parthyroid cells incubated with [(35)S]methionine. Proparathormone was detected at 10 min, the earliest time measured, and was rapidly and apparently quantitatively converted to parathormone. The half-life of the prohomormone pool was 15 min. Secretion of parathormone was detected by 20 min. In pulse-chase experiments there was a period between 20 and 40 min during which the wave of newly-synthesized parathormone was secreted. After 40 min during little additional radioactive hormone was secreted, but dibutyryl cyclic AMP, an agent that can mobilize stored parathormone, when added to the incubation mixtures enhanced radioactive parathormone secretion but only after 60 min, although it increased net hormone secretion as determined by radioimmunoassay to the same extent at all times studied. When the ionized calcium concentration of the medium was lowered, more radioactive hormone was secreted at all times but the effect was greatest on that hormone that was synthesized less than 60 min previously ; however, net hormone secretion in contrast to radioactive hormone was enhanced equally at all intervals. These data could mean that the refractoriness to secretion of parathormone 40-60 min of age was related to maturation of secretory container preparatory to storage. Low calcium (0.5 mM) stimulated hormone secretion up to fivefold compared to high calcium (3.0 mM) but did not affect synthesis of parathormone or proparathormne or conversion of the latter to hormone. During processing at least 70 percent of the intracellular parathormone was lost, presumably through proteolysis and this degradation was greater at high calcium. These data have been interpreted in light of the concept that two secretable pools of parathormone exist within the parathyroid.

Polydopamine-Mesoporous Silica Core-Shell Nanoparticles for Combined Photothermal Immunotherapy

Cancer immunotherapy involves a cascade of events that ultimately leads to cytotoxic immune cells effectively identifying and destroying cancer cells. Responsive nanomaterials, which enable spatiotemporal orchestration of various immunological events for mounting a highly potent and long-lasting antitumor immune response, are an attractive platform to overcome challenges associated with existing cancer immunotherapies. Here, we report a multifunctional near-infrared (NIR)-responsive core-shell nanoparticle, which enables (i) photothermal ablation of cancer cells for generating tumor-associated antigen (TAA) and (ii) triggered release of an immunomodulatory drug (gardiquimod) for starting a series of immunological events. The core of these nanostructures is composed of a polydopamine nanoparticle, which serves as a photothermal agent, and the shell is made of mesoporous silica, which serves as a drug carrier. We employed a phase-change material as a gatekeeper to achieve concurrent release of both TAA and adjuvant, thus efficiently activating the antigen-presenting cells. Photothermal immunotherapy enabled by these nanostructures resulted in regression of primary tumor and significantly improved inhibition of secondary tumor in a mouse melanoma model. These biocompatible, biodegradable, and NIR-responsive core-shell nanostructures simultaneously deliver payload and cause photothermal ablation of the cancer cells. Our results demonstrate potential of responsive nanomaterials in generating highly synergistic photothermal immunotherapeutic response.

Signalling elements in the ultradian rhythm of circulating growth hormone regulating expression of sex-dependent forms of hepatic cytochrome P450

Neonatal male rats were treated with monosodium glutamate (MSG) at either 2 or 4 mg/g BW on alternate days during the first 10 days of life. As adults, the 4 mg MSG-treated rats displayed the obesity, growth retardation, and reduced pituitary weights that typify this syndrome. These animals had no detectable plasma GH as determined from serial blood samples taken every 20 min for 8 consecutive h. Associated with this loss of circulating GH was an induction of the female-specific hepatic cytochrome P450 2d (gene IIC12) and the disappearance of the male-specific form of cytochrome P450 2c (gene IIC11). The catalytic activities of cytochrome P450 2c (i.e. androgen 16 alpha- and 2 alpha-hydroxylase), sex-dependent hexobarbital hydroxylase and total cytochrome P450 were similarly feminized. Rats exposed to the 2-mg dose of MSG were also obese, but their growth rates and pituitary sizes were not as severely affected as in the 4 mg MSG-treated rats. Circulating GH in these lower dosed males was secreted in a pulsatile pattern similar to that in normal males, except that the pulse amplitude was reduced as much as 90%. In spite of this profound decline in GH peak heights in the 2 mg MSG-treated males, liver metabolism was characteristically masculine. That is, female-specific cytochrome P450 2d remained undetectable, while the male forms of cytochrome P450 2c, 2a (gene IIIA2), and RLM2 (gene IIA2), their respective catalytic steroid hydroxylase activities, and associated sex-dependent drug-metabolizing enzymes were expressed at the level of or greater than that in normal males. Thus, while an ultradian pulse of circulating GH is necessary for the characteristically masculine profile of sex-specific forms of hepatic cytochrome P450, neither the amplitude of the secretory peaks nor their total GH content is critical, and these can be greatly reduced from the normal male levels.

Role of 1,25-dihydroxyvitamin D on the skeletal resistance to parathyroid hormone

Hypocalcemia in chronic renal failure (CRF) has been attributed in part to a skeletal resistance (S.R.) to the calcemic action of parathyroid hormone (PTH) as a consequence of low levels of 1,25(OH)2D3. To further elucidate the role of 1,25(OH)2D3 in the genesis of S.R., the calcemic effect of infusion of synthetic b-PTH 1-34 was examined in dogs before and after 7, 90 and 180 days of CRF. The maximum increment in ionized calcium after the infusion of PTH in the normal dogs was 1.15 +/- 0.13 mg/dl, decreased to 0.84 +/- 0.09 after 7 days, 0.68 +/- 0.1 after 90 days and to 0.66 +/- 0.11 mg/dl after 180 days of CRF. Thereafter, the dogs received 1,25(OH)2D3, 0.5 microgram daily for seven days and the studies were repeated. No improvement in the calcemic response to PTH was observed (0.57 +/- 0.26 mg/100 ml). Subsequently, a parathyroidectomy (PTX) was performed and 24 hours later the studies were repeated. After the infusion of PTH the calcemic response returned to normal (0.93 +/- 0.14 mg/dl). Further studies were performed in a group of four uremic dogs receiving no 1,25(OH)2D3, in which a PTX was performed 24 hours prior to the infusion of PTH. For this group, the increase in serum ionized calcium was 0.99 +/- 0.11 mg/dl. These values were not statistically different from normal dogs. In summary: (1) renal insufficiency was characterized by an abnormal calcemic response to PTH; (2) the administration of 1,25(OH)2D3 did not correct the S.R. to PTH; and (3) PTX performed 24 hours before the infusion of PTH restored the calcemic response to normal. These data suggest that high levels of endogenous parathyroid hormone desensitized the skeleton to the administration of exogenous PTH. These studies indicate that low values of 1,25(OH)2D3 are not directly responsible for the skeletal resistance to PTH in chronic renal failure.

Regulation of secretion of parathormone and secretory protein-I from separate intracellular pools by calcium, dibutyryl cyclic AMP, and (1)-isoproterenol

Dispersed porcine parathyroid cells were incubated at calcium concentrations between 0.5 and 3.0 mM in the presence of 3H- or 14C-amino acids to label newly synthesized parathormone. Up to four times more hormone was secreted at the lower calcium concentration but its specific radioactivity, from 30 to 50 times that of the intracellular pool, did not change. Dibutyrl cyclic AMP doubled immunoactive parathormone secretion at each calcium concentration, but there was no increase in secretion of radioactive hormone if labeled amino acids and secretagogue were added simultaneously. Similarly, when the intracellular pool of parathormone was prelabeled with 3H-amino acids and then the cells were incubated in 14C-amino acids and dibutyryl cyclic AMP, the entire increase in hormone secreted was derived from the prelabeled pool. (1)-isoproterenol increased intracellular cyclic AMP and acted on hormone secretion in a manner indistinguishable from dibutyryl cyclic AMP. In similar double-label experiments dibutyryl cyclic AMP preferentially enhanced secretion of secretory protein-I, a calcium-regulated protein of the parathyroid of unknown function. Calcium, alone, inhibited the intracellular level of cyclic AMP in a concentration-dependent fashion. These data are consistent with the existence in the parathyroid cell preparation of two hormone and secretory protein pools that may be individually recruitable--one consisting of most recently synthesized protein, the other consisting of older "storage" protein. The data do not allow one to decide whether the two pools coexist within individual cells or whether, instead, they exist in separate cells of the dispersed gland preparation.

Metal-Organic Framework Encapsulation Preserves the Bioactivity of Protein Therapeutics

Protein therapeutics are prone to lose their structure and bioactivity under various environmental stressors. This study reports a facile approach using a nanoporous material, zeolitic imidazolate framework-8 (ZIF-8), as an encapsulant for preserving the prototypic protein therapeutic, insulin, against different harsh conditions that may be encountered during storage, formulation, and transport, including elevated temperatures, mechanical agitation, and organic solvent. Both immunoassay and spectroscopy analyses demonstrate the preserved chemical stability and structural integrity of insulin offered by the ZIF-8 encapsulation. Biological activity of ZIF-8-preserved insulin after storage under accelerated degradation conditions (i.e., 40 °C) is evaluated in vivo using a diabetic mouse model, and shows comparable bioactivity to refrigeration-stored insulin (-20 °C). It is also demonstrated that ZIF-8-preserved insulin has low cytotoxicity in vitro and does not cause side effects in vivo. Furthermore, ZIF-8 residue can be completely removed by a simple purification step before insulin administration. This biopreservation approach is potentially applicable to diverse protein therapeutics, thus extending the benefits of advanced biologics to resource-limited settings and underserved populations/regions.

Metal-Organic Framework as a Protective Coating for Biodiagnostic Chips

Zeolitic imidazolate framework-8 (ZIF-8) grown around antibodies anchored to plasmonic nanostructures serves as a protective layer to preserve the biorecognition ability of antibodies stored at room and elevated temperatures for several days. The biofunctionality of the ZIF-8-protected biochip can be restored by a simple water-rinsing step, making it highly convenient for use in point-of-care and resource-limited settings.

Effect of AT2 receptor blockade on the pathogenesis of renal fibrosis

Cellular and molecular events contributing to tubulointerstitial fibrosis of the kidney during obstructive nephropathy are driven in large part through increased angiotensin II levels in the obstructed kidney. Angiotensin converting enzyme inhibition or AT1 receptor antagonism have been shown to ameliorate the fibrosis of the kidney due to obstruction of the ureter. In this investigation, we determine the effects of the AT2 receptor antagonist PD-123319 on pathophysiological events within the kidneys of rats with unilateral ureteral obstruction. Treatment with PD-123319 was found to exacerbate the increase in interstitial volume and collagen IV matrix score of the ureteral obstructed kidney. Monocyte/macrophage infiltration of the injured kidney was no different between treated and untreated animals. The AT2 receptor antagonist did, however, inhibit apoptosis of tubular cells, alpha-smooth muscle actin expression within the interstitium, and p53 expression in the ureteral obstructed kidney. These results suggest that angiotensin II operating through the AT2 receptor exerts an antifibrotic effect on the kidney during obstructive nephropathy in opposition to the profibrotic effects of angiotensin II operating through the AT1 receptor.

Injury in the era of genomics

The traditional approach to the study of biology employs small-scale experimentation that results in the description of a molecular sequence of known function or relevance. In the era of the genome the reverse is true, as large-scale cloning and gene sequencing come first, followed by the use of computational methods to systematically determine gene function and regulation. The overarching goal of this new approach is to translate the knowledge learned from a systematic, global analysis of genomic data into a complete understanding of biology. For investigators who study shock, the specific goal is to increase understanding of the adaptive response to injury at the level of the entire genome. This review describes our initial experience using DNA microarrays to profile stress-induced changes in gene expression. We conclude that efforts to apply genomics to the study of injury are best coordinated by multi-disciplinary groups, because of the extensive expertise required.