Preparation, Characterization and Study of the Dissociation of Naproxen from Its Chitosan Salt.

Salts of naproxen (NAP) with chitosan (CTS) and reticulated chitosan (CEP) were prepared under optimized conditions to maximize the yield of reaction. The objective was to evaluate the dissociation in water, which can guide studies of release of the drug from biopolymeric salts in pharmaceutical applications. Higher salification was found after 24 h of reaction at 60 °C in a molar ratio 1:1.05 (CTS:NAP, mol/mol), resulting in a degree of substitution (DS) of 17% according to 13C NMR, after neutralization of the -NH2 group of the biopolymer by the carboxylic group of the drug. The presence of NAP salt is evidenced by FTIR bands related to the -NH3+ group at 856 cm-1, a decrease in crystallinity index in XRD diffractograms as well as changes in mass loss ratios (TG/DTG/DTA) and increased thermal stability of the salt regarding CTS itself. The CEPN crosslinked salt presented a DS = 3.6%, probably due to the shielding of the -NH2 groups. Dissociation studies revealed that at pH 2.00, dissociation occurred faster when compared to at pH 7.00 in the non-reticulated salt, while the opposite was observed for the reticulated one.

Screen-printed disposable electrodes using graphite-polyurethane composites modified with magnetite and chitosan-coated magnetite nanoparticles for voltammetric epinephrine sensing: a comparative study.

Disposable screen-printed electrodes based on the use of graphite-polyurethane composites modified with magnetite nanoparticles (MNP-SPE) or chitosan-coated magnetite nanoparticles (CHMNP-SPE) are described. The MNP and CHMNP were synthetized and comparatively characterized by TEM, XRD, FTIR, and TGA/DTG. The MNP-SPE and CHMNP-SPE were characterized by SEM and EDX. After optimization of the MNP percentage in MNP-SPE, the materials were electrochemically characterized by cyclic voltammetry, EIS, and chronocoulometry. The electrodes were tested for their performance towards sensing of epinephrine (EP). The CHMNP-SPE is found to have better electrochemical responses in comparison to the MNP-SPE. This is assumed to be due to the chitosan coating which also protects the MNPs from oxidation under air and at different applied potential fields. The performances of the MNP-SPE and CHMNP-SPE were studied by DPV after optimization of equilibration time and DPV parameters. Response is linear in the 0.1-0.8 µM EP concentration range, at 0.03 V (vs. pseudo-Ag/AgCl), and the detection limit is 25 nM for the MNP-SPE. The linear response for the CHMNP-SPE was 0.1-0.6 µM, at 0.0 V (vs. pseudo-Ag/AgCl), and a LOD of 14 nM was achieved. The devices were used for the quantification of EP in synthetic urine and in cerebrospinal synthetic fluids. Recoveries from spiked samples are in the 95.6-102.2% range for the CHMNP-SPE and in the 98.3-109% range for MNP-SPE. The stability of the respective sensors was investigated and compared over a period of 5 months. The EP peak currents were found to decrease by only 4% for the CHMNP-SPE, while the MNP-SPE lost 23% of its EP peak current. Accordingly, the CHMNP-SPE was chosen as the most stable and sensitive sensor for EP. Graphical abstract Schematic figure of modification of a graphite-polyurethane screen-printed composite electrode with magnetite nanoparticles (MNPs) and chitosan-coated magnetite nanoparticles (CHMNPs) for the voltammetric determination of epinephrine (EP). Improved response of CHMNP-SPE (black voltammogram) in comparison to MNP-SPE (red voltammogram) was attributed to the protection of MNP from oxidation.

Nanodiamond based surface modified screen-printed electrodes for the simultaneous voltammetric determination of dopamine and uric acid.

The electroanalytical detection of the neurotransmitter dopamine (DA) in the presence of uric acid (UA) is explored for the first time using commercially procured nanodiamonds (NDs). These are electrically wired via surface modification upon screen-printed graphite macroelectrodes (SPEs). The surface coverage of the NDs on the SPEs was explored in order to optimize electroanalytical outputs to result in well-resolved signals and in low limits of detection. The (electro)analytical outputs are observed to be more sensitive than those achieved at bare (unmodified) SPEs. Such responses, previously reported in the academic literature have been reported to be electrocatalytic and have been previously attributed to the presence of surface sp2 carbon and oxygenated species on the surface of the NDs. However, XPS analysis reveals the commercial NDs to be solely composed of nonconductive sp3 carbon. The low/negligible electroconductivity of the NDs was further confirmed when ND paste electrodes were fabricated and found to exhibit no electrochemical activity. The electroanalytical enhancement, when using NDs electronically wired upon SPEs, is attributed not to the NDs themselves being electrocatalytic, as reported previously, but rather changes in mass transport where the inert NDs block the underlying electroactive SPEs and create a random array of graphite microelectrodes. The electrode was applied to simultaneous sensing of DA and UA at pH 5.5. Figures of merit include (a) low working potentials of around 0.27 and 0.35 V (vs. Ag/AgCl); and (b) detection limits of 5.7 × 10-7 and 8.9 × 10-7 M for DA and UA, respectively. Graphical abstract The electroanalytical enhancement of screen-printed electrodes modified with inert/non-conductive nanodiamonds is due to a change in mass transfer where the inert nanodiamonds facilitate the production of a random microelectrode array.

Targeted next-generation sequencing identifies molecular subgroups in squamous cell carcinoma of the head and neck with distinct outcome after concurrent chemoradiation.

BACKGROUND: Based on epidemiological (HPV status, smoking habits) and clinical risk factors (T/N stage), three subgroups of patients suffering from locally advanced oropharyngeal carcinoma with significantly different outcome after concurrent chemoradiation (cCRTX) can be distinguished. Mutational profiling by targeted next-generation sequencing (NGS) might further improve risk stratification. PATIENTS AND METHODS: Patients with stage IV squamous cell carcinoma of the oropharynx and hypopharynx who had been enrolled in a randomized phase III trial (ARO-0401) comparing two regimens of cCRTX and from whom archival tumor specimens were available were included. The HPV status was determined by p16 immunostaining and detection of HPV DNA. Targeted NGS covering 45 genes frequently altered in squamous cell carcinoma of the head and neck (SCCHN) was applied for detection of non-synonymous somatic and germline mutations. Interference of mutational profiles with cCRTX efficacy was determined. RESULTS: The prognostic value of the 'Ang' risk model could be confirmed in the total biomarker study cohort (N = 175) as well as the patient subgroup for which mutational profiles could be established (N = 97). Mutations in genes involved in phosphoinositide 3-kinase (PI3K), receptor tyrosine kinase (RTK), and p53 signaling pathways were significantly enriched in the low- (N = 7), intermediate- (N = 20), and high-risk group (N = 70), respectively. Mutations in TP53 identified a subgroup of high-risk patients with dismal outcome after cCRTX. No prognostic relevance was observed for mutations in PI3K and RTK signaling pathways in the low- and intermediate-risk groups, respectively. Mutated NOTCH1 and two functional KDR germline variants (rs2305948, rs1870377) were associated with improved outcome in all risk groups. All genetic markers (TP53, NOTCH1, KDR) remained independent prognosticators of OS in the multivariate model. CONCLUSION: A potential of targeted NGS for risk classification of SCCHN cases beyond HPV status and clinical factors was demonstrated.

Pen sensor made with silver nanoparticles decorating graphite-polyurethane electrodes to detect bisphenol-A in tap and river water samples.

Rapid, on-site detection of emerging pollutants is critical for monitoring health threats and the environment, especially if performed through autonomous systems. In this paper, we report on a new design of a complete electrochemical system whose working (WE), auxiliary (AE) and reference (RE) electrodes were obtained on a pen (PEN Sensor) made with graphite:polyurethane (GPUE). Working electrodes were decorated with spherical, ca. 200 nm silver nanoparticles (AgNPs) reduced on graphite using the polyol method. Differential pulse voltammetry (DPV) was used to detect bisphenol-A (BPA) in a linear range from 2.5 to 15 µmol L-1 with detection limit of 0.24 µmol L-1. The PEN Sensor could also detect bisphenol-A in tap and river water samples, with satisfactory reproducibility and repeatability, while common interferents did not affect electrooxidation of bisphenol-A. The high sensitivity and rapid detection are suitable for real-time analysis and in loco monitoring of emerging pollutants. With their robustness and versatility, PEN Sensors such as those fabricated here may be integrated into futuristic smart robotic systems.

Developing a screen-printed graphite-polyurethane composite electrode modified with gold nanoparticles for the voltammetric determination of dopamine.

A screen-printed electrode (SPGPUE) was prepared with graphite-polyurethane composite ink containing gold nanoparticles (AuNPs), resulting in a screen-printed graphite-polyurethane composite electrode modified with gold nanoparticles (SPGPUE-AuNPs). Gold nanoparticles were prepared by the citrate method and extracted from the water medium since polyurethane is not compatible with humidity. After extraction to chloroform, they were characterized via transmission electron microscopy (TEM). The presence of gold on the SPGPUE-AuNP surface was confirmed via SEM and EDX analyses, while thermogravimetry revealed the presence of approximately 3.0% (m/m) gold in the composite. An electrochemical pretreatment in 0.10 mol L-1 phosphate buffer (pH 7.0) with successive cycling between -1.0 V and 1.0 V (vs. pseudo-Ag/AgCl) under a scan rate of 200 mV s-1 and 150 cycles was required in order to provide a suitable electrochemical response for the voltammetric determination of dopamine. After the optimization of the parameters of differential pulse voltammetry (DPV), an analytical curve was obtained within a linear dynamic range of 0.40-60.0 µmol L-1 and detection limit (LOD) of 1.55 ×10-8 mol L-1 for dopamine at the SPGPUE-AuNP. A non-modified SPGPUE was used for comparison and a linear range was obtained between 2.0 and 10 µmol L-1 with an LOD of 2.94 × 10-7 mol L-1. During the dopamine determination in cerebrospinal synthetic fluid (CSF), recoveries between 89.3 and 103% were achieved. There were no significant interferences from ascorbic acid and uric acid, but some from epinephrine due to the structural similarity.

A new look towards the thermal decomposition of chitins and chitosans with different degrees of deacetylation by coupled TG-FTIR.

Chitins and Chitosans with different degrees of deacetylation (DD¯) were analyzed for the first time by thermogravimetry coupled to infrared spectroscopy TG-FTIR in order to evaluate the effect of DD¯ on the thermal decomposition process. DD¯ values of chitins and chitosans were determined by 1H-NMR and structural difference were investigated by FTIR, SEM and XRD. Thermal stability of chitosan with 98, 87, 71% DD¯, chitins with 47 and 27% DD¯ and commercial α-chitin were evaluated. Thermal decomposition of chitosans occurs in two steps, while for chitins occurs predominantly in first stage under air atmosphere. Commercial chitin thermally decomposed at lower temperatures than highly deacetylated chitosan. A faster thermal degradation process was found for chitins, except for commercial sample. TG-FTIR of evolved gas evidenced a complex gaseous mixture mainly composed by ammonia, acetic acid, acetamide, water, monoxide and carbon dioxide in proportions that are deeply dependent on the DD¯.

Characterization, solubility and biological activity of amphihilic biopolymeric Schiff bases synthesized using chitosans.

Chitosans are versatile biopolymers recognized for their wide range of biological activities. However, the low solubility in neutral and basic solutions restricts the applications. Thus amphiphilic biopolymeric Schiff bases from chitosans, salicylaldehyde and glycidol were successfully synthesized and characterized using 1H-NMR, UV/Vis, FTIR, TG/DTG-DTA and tested for their antimicrobial activities against plant pathogenic microorganisms and human breast cancer cells (MCF-7). Overall, functionalization of chitosans with salicylaldehyde and glycidol with different molecular weight (Mw¯) was performed to improve the biological actives of chitosans. Thus the biological activity of the new amphiphilic compounds prepared in this work were evaluated regarding microorganisms with agricultural relevance and tumor cells. The biopolymeric amphiphilic Schiff bases showed significant effects against Pseudomonas syringae (IC50 < 5 µg mL-1) compared to the natural chitosans with medium Mw¯ (CHM 223 kDa) and low Mw¯ (CHL 64 kDa), which had IC50 values of 42 and 37 µg mL-1, respectively. In addition, they improved antitumor activity against tumor cells compared to the natural chitosan.

Interference of tumour mutational burden with outcome of patients with head and neck cancer treated with definitive chemoradiation: a multicentre retrospective study of the German Cancer Consortium Radiation Oncology Group.

BACKGROUND: Tumour mutational burden (TMB) estimated from whole exome sequencing or comprehensive gene panels has previously been established as predictive factor of response to immune checkpoint inhibitors (ICIs). Its predictive value for the efficacy of concurrent chemoradiation (cCRTX), a potential combination partner of ICI, remains unknown. METHODS: The accuracy of TMB estimation by an in-house 327-gene panel was established in the Cancer Genome Atlas (TCGA) head and neck squamous cell carcinoma (HNSCC) data set. Interference of TMB with outcome after cCRTX was determined in a multicentre cohort of patients with locally advanced HNSCC uniformly treated with cCRTX. Targeted next-generation sequencing was successfully applied in 101 formalin-fixed, paraffin-embedded pretreatment tumour samples. In a subset of cases (n = 40), tumour RNA was used for immune-related gene expression profiling by the nanoString platform. TMB was correlated with TP53 genotype, human papilloma virus (HPV) status, immune expression signatures and survival parameters. Results were validated in the TCGA HNSCC cohort. RESULTS: A high accuracy of TMB estimation by the 327-gene panel was established. High TMB was significantly associated with an increased prevalence of TP53 mutations and immune gene expression patterns unrelated to T cell-inflamed gene expression profiles. Kaplan-Meier analysis revealed significantly reduced overall survival in the patient group with high TMB (hazard ratio for death: 1.79, 95% confidence interval: 1.02-3.14; P = 0.042) which remained significant after correcting for confounding factors in the multivariate model. The prognostic value of TMB was confirmed in the TCGA HNSCC cohort. CONCLUSION: High TMB identifies HNSCC patients with poor outcome after cCRTX who might preferentially benefit from CRTX-ICI combinations.

Chemical modification of alginate with cysteine and its application for the removal of Pb(II) from aqueous solutions.

It has been synthesized, characterized and tested a new biomaterial AlgS (sodium alginate functionalized with cysteine) to remove Pb(II) in aqueous media. The maximum Pb(II)-sorption capacity of AlgS (Qmax = 770 mg·g-1) is between almost two and nine times higher than other alginate-materials reported in the literature. Techniques, such as TGA/DSC, SEM/EDS, BET, FTIR, UV-Vis, XRD and 13C solid state-NMR have been used to study the chemical-modification of alginate at oxidation and aminofication stages. The formation of the imine intermediate (C=N), after 24 h of reaction was identified by a UV band at 348 nm. Typical IR-bands of AlgS were identified at 2970, 955, 949 and 1253 cm-1 which are associated to CH, SPb, SH and CN stretching vibrations, respectively. 13C solid state-NMR spectra of AlgS, show peaks at 33-38 ppm and 55-60 ppm associate to δ (HS-CH2-) of cysteine and δ (CN) respectively. The ΔH° and ΔG° negative values for Pb(II) sorption indicate that it is an exothermic process and occur spontaneously. Finally, it was found that the Pb(II) sorption on AlgS is significantly affected by the presence of cationic (Na+, Mg2+ and Al3+) and anionic (Cl-, NO3-) co-ions.

Chemical modification of sodium alginate with thiosemicarbazide for the removal of Pb(II) and Cd(II) from aqueous solutions.

A new material (AlgOx-TSC), based on alginate (Alg) chemically modified with thiosemicarbazide (TSC), has been synthesized and tested as an effective biomaterial to remove Pb(II) and Cd(II) ions in aqueous solutions. The synthesis was carried out by controlling the following steps, i/partial oxidation process of alginate in NaIO4 to obtain AlgOx, ii/reacting of AlgOx, at 40-45 °C, with TSC in NaBH4. AlgOx-TSC has been characterized by Field Emission Scanning Electron Microscopy (FESEM/EDS), Fourier Transform Infrared Spectroscopy (ATR-IR), solid state 13C NMR spectroscopy and Point of Zero Charge (pHPZC) measuremenmts. In order to enhance the sorption process, the effect of contact time, sorbent dosage, initial concentration and reusability of the novel sorbent were investigated becoming the AlgOx-TSC a promising material capable of removing high concentrations of heavy metal ions such as Pb(II) (up to 950 mg/g at pH 3) and Cd(II) (up to 300 mg/g at pH 7) in aqueous solutions.

Slow gastric emptying in type I diabetes: relation to autonomic and peripheral neuropathy, blood glucose, and glycemic control.

OBJECTIVE: To investigate whether autonomic neuropathy or hyperglycemia plays a crucial etiological role in gastric retention of ingesta frequently found in type I diabetic patients. RESEARCH DESIGN AND METHODS: We investigated the gastric emptying of a radiolabeled semisolid 1,168 kJ meal in 38 female and 45 male patients (age 18-75 years; illness duration 3-46 years). None took drugs affecting gastrointestinal motility. Fasted patients underwent tests of cardiovascular autonomic and peripheral nerve function. Blood glucose levels were determined before and after the scintigraphic recording of gastric emptying. RESULTS: The percentage of meal remaining in the stomach at the end of the 50-min recording time was related significantly to the patients' degree of cardiovascular autonomic neuropathy [r (81) = 0.235, P < 0.028] but not to their degree of peripheral neuropathy, preprandial blood glucose level, HbA1c indicative of glycemic control, diabetes duration, and age. The patients' mean residual percentage of meal was significantly greater than that of 48 healthy subjects, that is, 71.1 +/- 15.1 vs. 53.5 +/- 13.1% [means +/- SD; t (129) = 6.48, P < 0.0001]. The healthy individuals' mean residual percentage + 2 SD was exceeded in 22 patients. CONCLUSIONS: Slow gastric emptying in patients with type I diabetes seems related to the degree of autonomic neuropathy but not to peripheral neuropathy, actual blood glucose, and glycemic control.

Differential pulse anodic voltammetric determination of lithium ions in pharmaceutical formulations using a carbon paste electrode modified with spinel-type manganese oxide.

The use of the differential pulse voltammetry for the determination of lithium ions in pharmaceutical samples using a carbon paste electrode modified with spinel-type manganese oxide has been examined. The best voltammetric response was reached for a modified electrode in borate buffer solution of pH 9.0 and submitted to a scan rate of 5 mV s(-1) and a pulse amplitude of 50 mV. This electroanalytical procedure was able to determine lithium ions in the concentration range of 8.0 x 10(-5)-1.0 x 10(-2) mol l(-1) even in the presence of several alkali metals (1.0 x 10(-3) mol l(-1)) with a detection limit of 7.1 x 10(-7) mol l(-1). Rapidity, precise and good selectivity were also found for the determination of lithium ions in pharmaceutical formulations.

Flow injection amperometric determination of dipyrone in pharmaceutical formulations using a carbon paste electrode.

The behavior of a carbon paste electrode was investigated as an amperometric detector for the determination of dipyrone by flow injection analysis (FIA). The electrode presented low cost and easy construction by simple mixing of graphite powder and mineral oil. Initially, an electrochemical study of the dipyrone oxidation at a carbon paste electrode has been developed before its use in the FIA system. The oxidation currents monitored at +0.35 V versus Ag/AgCl, were proportional to the dipyrone concentrations. Experimental parameters, such as nature of supporting electrolyte, pH of the carrier solution, flow rate, sample volume injection and probable interferents were investigated. Under the best experimental conditions selected, the calibration curve for dipyrone was linear in the concentration range from 4.91 x 10(-6) to 2.50 x 10(-4) M l(-1) (I(anodic)/microA)=0.056+81.06 [dipyrone]) with a detection limit of 2.07 x 10(-6) M l(-1). Recoveries ranged from 93.8 to 100.8% and an analytical frequency of 130 h(-1) was achieved. The proposed flow procedure has been satisfactorily applied to the determination of dipyrone in several pharmaceutical formulations.

Clinical and imaging diagnosis of lesions of the labrum acetabulare.

Labral lesions are common findings in residual hip dysplasia, indicating biomechanical decompensation of the hip joint. MR-Arthrography has shown an excellent accuracy of over 90 % to detect these lesions. Nevertheless, so far clinical sings, radiological diagnosis and therapeutical consequences are not well known. In a prospective study, patients suspicious for labral lesions were evaluated using a standard clinical protocol, including history, clinical signs, radiography and MR-Arthrography. Clinical signs were tested by six criteria and two provocation tests. In 11 % patients clinical suspicious was wrong. Best agreement with MR-Arthrography was found for "knife sharp" groin pain (100 %), impingement test (100 %) and painful giving way (83 %). 35 % of patients showed minor (grade 2) and 52 % severe (grade 3 and 4) dysplasia. Independent from grade of dysplasia, no or only slight arthrosis (grade 0 and 1) was found in 64 % of patients. In 16 % a single acetabular cyst could be detected on radiographs, which all could be identified as intraosseous ganglia on MR-Arthrography. Labral lesions type A (post traumatic) were found in 23 % of the patients with only no or minor dysplasia (grade 1 and 2), whereas labral lesions type B (dysplastic) were found in 67 % of the patients with severe dysplasia (grade 3 and 4). Clinical signs for labral lesions are typical but can also be observed in other pathologies of the hip joint. Based on the findings of this study, we recommend radiographic evaluation for dysplasia and MR-Arthrography in patients with clinical suspicion for labral lesions of the hip joint.

[Biotransformation and pharmacokinetics of mesoionic didehydro-4-methyl-5-phenyl-1,3,4-thiadiazolidine-2-thione (LU 2443). Studies on its biotransformation in rats]. / Biotransformation und Pharmakokinetik von mesoionischem Didehydro-4-methyl-5-phenyl-1,3,4-thiadiazolidin-2-thion (LU 2443). Untersuchungen zur Biotransformation an Ratten.

The metabolism of the antiepileptic mesoionic didehydro-4-methyl-5-phenyl-1,3,4-thiadiazolidine-2-thione (LU 2443) was investigated after p.o. application in rats. The main metabolite was benzoic acid, besides the unchanged material and hippuric acid the spasmodically compounds N-methyl-benzamide and mesionic didehydro-4-methyl-5-phenyl-1,3,4-thiadiazolidine-2-one were detectable. In-vitro experiments could be demonstrated that LU 2443 was not demethylated by biochemical oxidation, and LU 2443 was also very stable against metabolizing influences by enteric bacteria.

[Biotransformation and pharmacokinetics of mesionic didehydro-4-methyl-5-phenyl-1,3,4-thiadiazolidine-2-thione (LU 2443). Studies on the pharmacokinetics in rats]. / Biotransformation und Pharmakokinetik von mesoionischem Didehydro-4-methyl-5-phenyl-1,3,4-thiadiazolidin-2-thion (LU 2443). Untersuchungen zur Pharmakokinetik an Ratten.

After p.o. application in rats the pharmacokinetic properties of the mesionic dihydro-4-methyl-5-phenyl-1,3,4-thiadiazolidine-2-thione (LU 2443) were examined. The compound is extensively absorbed, in the maximum 18% are eliminated unabsorbed. The half-time of the activity in plasma is 13.17 h, the highest concentration in plasma after p.o. application as a solution of polyethyleneglycol is reached after 5.09 h. The elimination is mainly renal--namely 61.9%, 28.7% are eliminated with the faeces. After 96 h 90.6% of the applicated activity was eliminated. The distribution of LU 2443 was in the whole organism; entrance of the compound into liquor was proven. By radiography of the total animal a transient accumulation of LU 2443 and its metabolites in liver and kidney was determined; besides, a considerable concentration of activity in the suprarenal medulla was found.

A histochemical study of aldehyde fuchsin-positive material and "high-esterase cells" in the pineal gland of the Mongolian gerbil.

The pineal gland of the Mongolian gerbil consists of a superficial gland, stalk and deep pineal. The deep pineal differentiates postnatally. Histochemical studies of the superficial pineal gland indicate that it may be involved in the secretion of protein. Presumptive secretory material visualized by aldehyde fuchsin (AF) and chrome hematoxylin was observed along the course of blood vessels and among the pinealocytes. The distribution and texture of the AF-positive material was distinctive. It did not correspond to the pattern and texture of material stained with PAS, Sudan Black or acid orcein. Staining with AF was markedly reduced after incubation with trypsin, indicating that the AF-positive material is at least partially protein. The amount of stainable material increased with age. The AF-positive material was observed in what appeared to be interstitial or glial cells and processes, and in the processes of perivascular cells. Cells and fibrous processes with high non-specific esterase activity ("high-esterase cells") were observed among the pinealocytes and along the course of blood vessels. The distribution of the "high-esterase cells" and the morphology and texture of their esterase-containing processes were remarkably similar to the morphology and distribution of the material that stained with AF. It may be that the "high-esterase cells" contain AF-positive material. The "high-esterase cells" hydrolyzed both alpha-naphthyl acetate and alpha-naphthyl butyrate. The pinealocytes hydrolyzed only alpha-naphthyl acetate. The "high-esterase cells" appear to form a distinct class of cells within the superficial pineal gland. They are tentatively identified as a type of glial cell.

Calcified inclusions in the superficial pineal gland of the mongolian gerbil, Meriones unguiculatus.

A histological and histochemical study of the pineal gland of neonatal, juvenile and adult gerbils is described. Calcified inclusions appear within pinealocytes in the superficial pineal about the third week of age, and the incidence of inclusions increased with age until, by the eleventh week, they are found in all animals. The inclusions contain an organic matrix composed of a carbohydrate, probably an acid mucopolysaccharide, complexed to protein. Calcification does not occur in the deep pineal. The data are interpreted to indicate that the formation of calcified inclusions is a normal process within the gerbil pineal. The similarity of the process of calcification in the gerbil and in the human pineal suggests that the gerbil may be an animal of choice for the controlled study of the phenomenon of pineal calcification.