Direct effects of serotonin and ketanserin on the functional morphology of embryonic chick skin in vitro

Summary Different organotypical culture methods are used to test the direct effects of serotonin and ketanserin, a S₂, α₁, and H₁ receptor antagonist in vascular tissue, on fibroblasts and epidermal cells of embryonic chick skin in vitro. From light microscopic and electron microscopic analyses, we learn that serotonin enhances keratinization and differentiation, whereas ketanserin reduces differentiation in comparison to the control cultures. Incorporation data of fragments cultured with [³H]thymidine show that ketanserin, within a dose range from 0.05 to 5 μg/ml, stimulates proliferation. Serotonin at a concentration of 10 μg/ml slightly slows down proliferation, whereas lower doses of 0.1 and 1 μg/ml result in tritium activities that do not differ from control cultures. This investigation was financially supported by the National Fund of Scientific Research, Belgium, 3.0022.87.     

Amyloidosis in pigtailed macaques (Macaca nemestrina): pathologic aspects

The pathologic aspects of 248 cases of amyloidosis in pigtailed macaques (Macaca nemestrina) at the Washington Regional Primate Research Center from 1971 through 1985 were studied. Amyloid was present in the spleen, liver and gastrointestinal (GI) tract, either alone or in combination, in nearly 75% of the monkeys. Its occurrence declined with age in the spleen and the GI tract, but increased with age in the liver. Both intestinal inflammation and retroperitoneal fibromatosis were strongly associated with amyloid deposition in the GI tract. Monkeys with histopathologic findings of enteritis or enterocolitis and glomerulonephritis were at increased risk of developing amyloidosis. Forty cases of amyloidosis with a history of chronic diarrhea had type AA amyloid by histochemical tests.     

Amyloidosis in pigtailed macaques (Macaca nemestrina): epidemiologic aspects

A retrospective study of amyloidosis in pigtailed macaques (Macaca nemestrina) at the Washington Regional Primate Research Center (WRPRC) was conducted. Between 1971 and 1985, 248 of 1,952 (13%) necropsies revealed amyloidosis in pigtailed macaques. The influence of demographic factors, diseases and experimental interventions on amyloidosis was examined. Univariate analyses, using two controls for each case, indicated that age, sex, birthplace and residence were related to amyloidosis. After adjusting for age, females were not at greater risk. However, monkeys born at the WRPRC were at greater risk and monkeys 0 to 5 years old residing at the breeding colony were at greater risk than monkeys at the research center. After adjustment for age, monkeys were at greater risk of developing amyloidosis if they had a history of episodes of diarrhea, respiratory disease or trauma. As the number of episodes increased, the risk increased. Monkeys with retroperitoneal fibromatosis, a manifestation of simian D retrovirus infection, were also at greater risk. Using logistic regression and controlling for age, sex, birthplace and residence, monkeys with diarrhea remained at an elevated risk for amyloidosis. Compared with a model combining diarrhea, respiratory disease, septicemia, surgery, trauma and retroperitoneal fibromatosis, a model with diarrhea alone accounted for most of the increased risk.     

Variability of entrainment of cohesive sediments in freshwater

Estimates of sediment entrainment are required for models of particle transport in lakes and estuaries but are difficult to make because of the multiplicity of factors affecting cohesiveness of surficial sediments. We present results of sediment resuspension studies performed in an annular flume calibrated with laser-Doppler velocimetry. In our experiments, using sediments collected from two sites in the R. Raisin which flows into L. Erie and from one site in the western basin of L. Erie near the mouth of the R. Raisin, we applied shear stresses at the sediment-water interface in steps from 2 to 12 dyne/cm². Percent water content at the surface of the sediments was either 77 or 74%, and trials were run with and without oxygenating the water overlying the sediments. Entrainment rates as a function of shear stress at the sediment-water interface were best described by a power-law relationship. All but 14% of the variability in the power law expression was due to shear stress and percent water content; the variability not accounted for was due to differences in particle size distributions, chemical properties, and biological activity in the sediments.     

Video microscopic analysis of ionophore induced acrosome reactions of lobster (Homarus americanus) sperm

Sperm from the American lobster (Homarus americanus) are normally nonmotile. However, during fertilization, the sperm undergo a calcium-dependent acrosome reaction that propels them forward about 18 μMm. The reaction occurs in two phases, eversion and ejection, which take place too quickly to permit analysis by direct observation. The purposes of this study were to examine the structural changes occurring in sperm during the normal acrosome reaction and to determine the rate of the reaction using video microscopy. The reaction was induced in vitro by ionophore A23187 and recorded using a video system attached to a Nikon Nomarski interference microscope. Videotapes were played back frame by frame (30 frames/sec), and images of reactions from 10 sperm were analyzed. The acrosome reaction, including the eversion of the acrosomal vesicle and ejection of the subacrosomal material and nucleus, can be divided into 4 steps: (1) expansion of the apical cap followed by expansion of the remainder of the acrosomal cylinder; expansion of the cylinder begins at its apical end and proceeds toward its base, (2) eversion of the apical half of the acrosomal vesicle and initial contraction of the apical cap, (3) eversion of the basal half of the acrosomal vesicle, continued contraction of the apical cap, and ejection of the subacrosomal material and nucleus, and (4) final contraction of the apical cap and ejection of the acrosomal filament. During steps 2, 3, and 4, the mean forward movement of sperm is 12.7, 3.9, and 1.1 μMm, respectively. Although the time required to complete the reaction ranged from 0.66 to 5.16 s, most sperm reacted in less than 3. s, and these sperm were considered to have typical rates. For sperm that reacted in less than 3 s, both step 1 and step 4 take about 0.2 s and show little variation among sperm. the time required to complete steps 2 and 3 averaged 0.63 and 0.37 s, respectively. Forward movement of the sperm during the acrosome reaction is caused by eversion of the inner and outer acrosomal material and contraction of the apical cap. The protein(s) responsible for this contraction is not yet known. © 1993 Wiley-Liss, Inc.     

Reaction intensification for biocatalytic production of polyphenolic natural product di-C-β-glucosides

Polyphenolic aglycones featuring two sugars individually attached via C-glycosidic linkage (di-C-glycosides) represent a rare class of plant natural products with unique physicochemical properties and biological activities. Natural scarcity of such di-C-glycosides limits their use-inspired exploration as pharmaceutical ingredients. Here, we show a biocatalytic process technology for reaction-intensified production of the di-C-β-glucosides of two representative phenol substrates, phloretin (a natural flavonoid) and phenyl-trihydroxyacetophenone (a phenolic synthon for synthesis), from sucrose. The synthesis proceeds via an iterative two-fold C-glycosylation of the respective aglycone, supplied as inclusion complex with 2-hydroxypropyl β-cyclodextrin for enhanced water solubility of up to 50 mmol/L, catalyzed by a kumquat di-C-glycosyltransferase (di-CGT), and it uses UDP-Glc provided in situ from sucrose by a soybean sucrose synthase, with catalytic amounts (≤3 mol%) of UDP added. Time course analysis reveals the second C-glycosylation as rate-limiting (0.4–0.5 mmol/L/min) for the di-C-glucoside production. With internal supply from sucrose keeping the UDP-Glc at a constant steady-state concentration (≥50% of the UDP added) during the reaction, the di-C-glycosylation is driven to completion (≥95% yield). Contrary to the mono-C-glucoside intermediate which is stable, the di-C-glucoside requires the addition of reducing agent (10 mmol/L 2-mercaptoethanol) to prevent its decomposition during the synthesis. Both di-C-glucosides are isolated from the reaction mixtures in excellent purity (≥95%), and their expected structures are confirmed by NMR. Collectively, this study demonstrates efficient glycosyltransferase cascade reaction for flexible use in natural product di-C-β-glucoside synthesis from expedient substrates.     

Clinical phenotype of nephrogenic diabetes insipidus in females heterozygous for a vasopressin type 2 receptor mutation

Nephrogenic diabetes insipidus (NDI) usually shows an X-linked recessive mode of inheritance caused by mutations in the vasopressin type 2 receptor gene (AVPR2). In the present study, three NDI families are described in which females show clinical features resembling the phenotype in males. Maximal urine osmolality in three female patients did not exceed 200 mosmol/kg and the absence of extra-renal responses to 1-desamino-8-d-arginine vasopressin was demonstrated in two of them. All affected females and two asymptomatic female family members were shown to be heterozygous for an AVPR2 mutation. Skewed X-inactivation is the most likely explanation for the clinical manifestation of NDI in female carriers of an AVPR2 mutation. It is concluded that, in female NDI patients, the possibility of heterozygosity for an AVPR2 gene mutation has to be considered in addition to homozygosity for mutations in the aquaporin 2 gene.     

Stereoselective action of acylated crude papain toward mandelic and atrolactic hydrazides

Acylated crude papain has been shown to exert stereoselective behavior toward racemic hydrazides devoid of an amino acid residue, namely, (RS)-mandelic and (RS)-atrolactic hydrazides. These hydrazides functioned as nucleophiles to yield N¹,N²-diacylhydrazines. Several achiral acylating agents for the enzyme were chosen, including Z-glycine, BOC-glycine, AOC-glycine, and hippuric acid. With the exception of hippuric acid as the acylating agent, the reaction product, in every instance for these achiral hydrazides, consisted of an excess of the (+)-N¹,N²-diacylhydrazine. The relative rates of product formation for the mandelic hydrazides were considerably greater than for corresponding reactions with racemic atrolactic hydrazide. When chiral Z-l-alanine was employed to acylate crude papain, the stereoselective action was most pronounced, with the formation of a mixture of diastereoisomers consisting of 73% N¹-(Z-l-alanyl)-N²-[(R)-mandelyl]hydrazine. The relative reactivities for the electrophiles was Z-l-alanine ? Z-glycine ? hippuric acid ? AOC-glycine > BOC-glycine. The hydrazides of (R)-, (S)-mandelic, and (RS)-atrolactic acids were prepared by conversion of the corresponding acids to their esters by means of a catalytic dehydrating agent and subsequent treatment with a methanolic solution of hydrazine.     

Dissociation of polysome aggregates by protease k

Apparent large size-classes of zein-synthesizing polysomes from developing kernels of Zea mays L. were converted to smaller polysomes after treatment with Protease K. The reduction in polysome size was not a result of ribonuclease activity, inasmuch as the enzyme did not affect the free polysomes or the size of the mRNA from the membrane-bound polysomes. High concentrations of MgCl(2) in polysome buffer inhibited ribonuclease activity and appeared to cause protein interaction between nascent zein polypeptides. Although Protease K inhibited the polysome's capacity for protein synthesis, it was a useful reagent for determining if polysomes were aggregated by protein.