Study of pharyngeal airway morphology with CBCT: Benefits of four premolar extraction orthodontic treatments

BACKGROUND AND AIM

Four premolars extractions are routine procedures for correction of malocclusion, but will inevitably lead to a reduction of tongue space, whether this will weaken the pharyngeal airway remains a controversy.

PATIENTS AND METHODS

Cone-beam computed tomography (CBCT) radiographs of 80 patients who completed four premolar extraction orthodontic treatments were collected and divided into three anteroposterior skeletal groups according to the ANB (angle subspinale to nasion to supramentale) value. Linear, angular, cross-sectional area, and volumetric dimensions of the pharyngeal airway were measured using Dolphin Imaging 11.9 software. One-way analysis of variance and Pearson's correlation coefficient test were performed to assess the intergroup comparisons. Treatment changes were evaluated with two-sample t-tests.

RESULTS

In intergroup comparisons, vertical linear and cross-sectional area differences were identified in S-Go/N-Me, VD1, VD1/N-Me, VD2/N-Me, AA, OAA and OMINI (p<0.05), while other measurements showed no significant differences. Angle2, the tilting degree of the pharyngeal airway, showed a positive correlation with ANB (p<0.05). As for the treatment changes, a significant increase was found in the pharyngeal airway in the Class I group (OUA p<0.05, VD1 p<0.001, VD2 p<0.05) and Class II group (VD1 p<0.001. VD2, p<0.05), and inversely, a significant decrease was found in the pharyngeal airway in the Class III group (OAA p<0.05, OMINI p<0.05, OUA p<0.05). No volumetric difference was identified. Interestingly, regarding the preoperative pharyngeal airway size, values trended to the mean value significantly.

CONCLUSION

Four premolar extraction orthodontic treatments did not affect the pharyngeal airway volume except for the vertical liner and cross-sectional area dimensions. The trend of the gold standard suggested a positive influence of four premolar extraction orthodontic treatments.

Investigating the feasibility of tumour molecular profiling in gastrointestinal malignancies in routine clinical practice

Background

Targeted capture sequencing can potentially facilitate precision medicine, but the feasibility of this approach in gastrointestinal (GI) malignancies is unknown.

Patients and methods

The FOrMAT (Feasibility of a Molecular Characterisation Approach to Treatment) study was a feasibility study enrolling patients with advanced GI malignancies from February 2014 to November 2015. Targeted capture sequencing (mainly using archival formalin-fixed paraffin-embedded diagnostic/resection samples) was carried out to detect mutations, copy number variations and translocations in up to 46 genes which had prognostic/predictive significance or were targets in current/upcoming clinical trials.

Results

Of the 222 patients recruited, 215 patients (96.8%) had available tissue samples, 125 patients (56.3%) had ≥16 genes successfully sequenced and 136 patients (61.2%) had ≥1 genes successfully sequenced. Sample characteristics influenced the proportion of successfully sequenced samples, e.g. tumour type (colorectal 70.9%, biliary 52.6%, oesophagogastric 50.7%, pancreas 27.3%, P = 0.002), tumour cellularity (high versus low: 78.3% versus 13.3%, P ≤ 0.001), tumour content (high versus low: 78.6% versus 27.3%, P = 0.001) and type of sample (resection versus biopsy: 82.4% versus 47.6%, P ≤ 0.001). Currently, actionable alterations were detected in 90 (40.5%) of the 222 patients recruited (66% of the 136 patients sequenced) and 2 patients subsequently received a targeted therapy. The most frequently detected currently actionable alterations were mutations in KRAS, BRAF, TP53 and PIK3CA. For the 205 patients with archival samples, the median time to obtain sequencing results was 18.9 weeks, including a median of 4.9 weeks for sample retrieval and 5.1 weeks for sequencing.

Conclusions

Targeted sequencing detected actionable alterations in formalin-fixed paraffin-embedded samples, but tissue characteristics are of critical importance in determining sequencing success. Routine molecular profiling of GI tumours outside of clinical trials is not an effective use of healthcare resources unless more targeted drugs become available.

ClinicalTrials.gov identifier

NCT02112357.

Kinetic studies of the degradation of oxycarbonyloxymethyl prodrug of Adefovir and Tenofovir in solution

The decomposition kinetics of bis-POC PMEA and bis-POC PMPA followed pseudo-first order kinetics with the corresponding mono-POC ester detected as the only observable degradation product for all the pH values studied. The rates of hydrolysis of bis-POC PMEA over the pH range studied was described by [formula: see text] The 18O incorporation studies revealed that hydrolysis of bis-POC PMEA at pH 7.0 primarily proceeds via P-O cleavage with an additional minor pathway involving C-O bond cleavage. Hydrolysis of bis-POC PMPA was found to be about 2 fold slower than bis-POC PMEA at pH values above 6.0.

Effect of carbonate salts on the kinetics of acid-catalyzed dimerization of adefovir dipivoxil

PURPOSE

The chemical stability and product(s) distribution of adefovir dipivoxil (ADV) was examined in the presence of soluble and insoluble carbonate salts.

METHODS

Chemical stability of ADV in the solid state at 60 degrees C/30% RH was examined. Stability was also examined in the presence of excess formaldehyde vapor at 23 degrees C/53% RH. ADV and its degradation product(s) were determined by reverse phase HPLC.

RESULTS

Addition of aqueous soluble carbonate salts, such as sodium carbonate, compromised the stability of ADV in solid state. However, aqueous insoluble carbonates, such as calcium carbonate and magnesium carbonate, enhanced the stability of ADV as compared to the control formulation. Pivalic acid, a degradation product of ADV, was shown to accelerate the degradation rate of ADV in solid state. The de-stabilizing effect of this acid on ADV stability was diminished in the presence of magnesium carbonate. Pivalic acid also increased the rate at which ADV dimers were formed in the presence of formaldehyde vapor. Addition of insoluble carbonates reduced the rate of formaldehyde-catalyzed dimerization of ADV.

CONCLUSIONS

Addition of insoluble carbonate salts decreased the rate of degradation of ADV by minimizing the extent of formaldehyde-catalyzed dimerization in solid state.

Enhanced chemical stability of the intracellular prodrug, 1-[((S)-2-hydroxy-2-oxo-1,4,2-dioxaphosphorinan-5-yl)methyl]cytosine, relative to its parent compound, cidofovir

Degradation kinetics of cyclic HPMPC (cHPMPC), 1-[((S)-2-hydroxy-2-oxo-1,4,2-dioxaphosphorinan-5-yl)methyl]cytosi ne, and its parent compound cidofovir (also known as HPMPC) were conducted in the pH range of 2-11 at 70 degrees C. cHPMPC manifested greater chemical stability than cidofovir, except under alkaline conditions (pH?9). Three degradation products-cidofovir, cyclic HPMPU and HPMPU-were identified for cHPMPC, and the product distribution was characterized via a stability-indicating HPLC assay. Cyclic HPMPU and HPMPU are the uracil analogs of cHPMPC and cidofovir, respectively, formed through a hydrolytic deamination pathway. The deamination and hydrolysis rate constants for cHPMPC under acidic conditions were derived from the degradation product curves. The deamination rate constants for cHPMPC were about 8-fold slower compared to that for cidofovir. The enhanced chemical stability for cHPMPC relative to cidofovir is attributed to the absence of intramolecular catalysis with cHPMPC.

Biexponential decomposition of a neuraminidase inhibitor prodrug (GS-4104) in aqueous solution

PURPOSE

To examine the degradation kinetics and identify the degradation products of a neuraminidase inhibitor prodrug. GS-4104.

METHODS

Degradation was studied as a function of pH and temperature using a stability-indicating RP-HPLC assay. Degradation products were isolated by RP-HPLC and identified by NMR. Specific rate constants were calculated based on a scheme defined by products(s) analysis.

RESULTS

Three distinct degradation products were observed in the pH region studied (pH 2-8): isomer I, GS-4071, and isomer II. Isomer I resulted from the N, N-migration of the acetyl group. Gs-4071 was formed by the hydrolysis of the ethyl ester. Both GS-4071 and isomer I degraded further to isomer II by N, N-acyl migration and ester hydrolysis, respectively. The N, N-acyl migration reaction was characterized using two dimensional heteronuclear multiple bond correlation (HMBC) NMR. The decomposition kinetics of GS-4104 follow a biexponential decay at pH 2-7. The degradation kinetics of Gs-4104 at pH 4.0, 70 degree C were independent of the initial GS-4104 concentration.

CONCLUSIONS

The degradation profile indicates that development of solution or solid dosage from of GS-4104 with adequate shelf-life stability at room temperature is feasible.

Risk of relapse in leprosy after fixed-duration multidrug therapy

Between 1986 and 1995, 8307 leprosy patients have completed fixed-duration multidrug therapy (FD-MDT) and were followed annually for possible relapse. The mean relapse rate for multibacillary (MB) leprosy is 0.15/1000 person-years (py) and for paucibacillary (PB) 0.55/1000 py. There is no difference in the relapse rates between patients with or without chemotherapy before FD-MDT. In MB patients, the five relapses occurred between 4 and 7 years; in PB patients, five relapses occurred at 4-5 years after FD-MDT. Six additional PB relapses self-reported 1-4 years after the 5-year surveillance period and were not included in the relapse rates. Most PB patients relapsed into MB due to wrong classification and insufficient therapy. For the known 62 irregular MB patients the cumulative relapse rate is 6.5%.

Characterization of metal-ion-nucleotide based particulate matter in solutions of 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA)

The antiviral drug 9-[2-(phosphonomethoxy)ethyl]adenine, PMEA, was developed as an intravenous product for the treatment of human immunodeficiency virus infection. During the course of stability monitoring, PMEA i.v. injection was found to undergo particulate matter formation under extended storage at ambient temperature. Isolation and characterization of the particulates revealed them to be metal ion-PMEA complexes. The principle metal ions associated with the particulates were iron and zinc, present as trace impurities (< or = 40 ppm) in PMEA drug substance determined by inductively coupled argon plasma spectroscopy. These visible particles are characterized by energy-dispersive x-ray spectrometry and fourier transform infrared spectroscopy. This study describes the systematic evaluation of the observed solution phenomena and details alternative formulation systems to eliminate particulate formation in the PMEA injectable product.

Stability of cidofovir in 0.9% sodium chloride injection and in 5% dextrose injection

The stability of cidofovir in i.v. admixtures under refrigerator and room temperature conditions was studied. Admixtures of cidofovir 0.21 and 8.12 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection and of 0.085 and 3.51 mg/mL in 5% dextrose and 0.45% sodium chloride injection were prepared in triplicate in polyvinyl chloride (PVC) or polyethylene-polypropylene containers and i.v. administration sets and stored for 24 hours at 2-8 or 30 degrees C. The lower concentration of cidofovir corresponded to an assumed dose of 0.5 mg/kg for a 40-kg patient, and the higher concentration to an assumed dose of 10 mg/kg for a 100-kg patient. Samples were removed at 0 and 24 hours and analyzed for cidofovir concentration by high-performance liquid chromatography. Physical compatibility was also studied. The stability of cidofovir in 0.9% sodium chloride injection and in 5% dextrose injection at low- and high-dose concentrations was unaffected by storage at either temperature. All admixtures were clear, colorless, and free of visible particles or precipitation. There were no substantial changes in pH or number of particles of > or = 10 microns in diameter. Cidofovir 0.21 and 0.12 mg/mL was stable in 0.9% sodium chloride injection and 5% dextrose injection in PVC and polyethylene-polypropylene containers and i.v. administration sets for up to 24 hours at 2-8 and 30 degrees C. Cidofovir was compatible with the injectable solutions studied.

Uncleaved signals for glycosylphosphatidylinositol anchoring cause retention of precursor proteins in the endoplasmic reticulum

Glycosylphosphatidylinositol (GPI)-anchored proteins are generally absent from the surface of cells that are defective in GPI biosynthesis. The current study was undertaken to: (a) examine in detail the intracellular localization and fate of precursors of GPI-anchored proteins in cells that fail to add GPI groups and (b) define structural characteristics of the precursor proteins that determine their intracellular localization. By examining GPI-deficient cells, we show that the uncleaved precursor of the GPI-anchored protein, Q7b, is retained in the cisternae of the endoplasmic reticulum (ER) and is largely lost intracellularly with a half-time of 2-4 h. Only a small amount (1-10%) of a proteolytically cleaved form of the protein is secreted into the medium. In cells competent for GPI anchor addition, mutation of the putative cleavage/attachment site for GPI addition in Q7b results in a similar phenotype of ER retention of the uncleaved precursor. An aspartic acid residue (Asp316) within the Q7b GPI anchoring signal, previously found to be essential for GPI anchor addition (Waneck, G. L., Stein, M. E., and Flavell, R. A. (1988) Science 241, 697-699), is also shown to be critical for ER retention. Information leading to ER retention is transferable to another protein leading to ER retention is transferable to another protein by fusion of the GPI anchoring signals from either Q7b or the GPI-anchored form of the IgG Fc receptor type III. Analysis by sedimentation on sucrose gradients shows that Q7b species retained in the ER are multimeric, whereas species that exit the ER are monomeric. This correlation suggests that the presence of an uncleaved signal for GPI anchoring induces changes in the aggregation state of the precursor proteins, which may lead to their retention in the ER.

Localization of TGN38 to the trans-Golgi network: involvement of a cytoplasmic tyrosine-containing sequence

Protein localization to the TGN was investigated by examining the subcellular distribution of chimeric proteins in which the cytoplasmic and/or transmembrane domains of the TGN protein, TGN38, were substituted for the analogous domains of the plasma membrane protein, Tac. Using immunofluorescence and immunoelectron microscopy, the COOH-terminal cytoplasmic domain of TGN38 was found to be sufficient for localization of the chimeric proteins to the TGN. Deletion analysis identified an 11-amino acid segment containing the critical sequence, YQRL, as being sufficient for TGN localization. TGN localization was abrogated by mutation of the tyrosine or leucine residues in this sequence to alanine, or of the arginine residue to aspartate. In addition to specifying TGN localization, the 11-amino acid segment was active as an internalization signal, although the property of internalization alone was insufficient to confer TGN localization. Overexpression of chimeric proteins containing TGN localization determinants resulted in their detection at the plasma membrane and in intracellular vesicles, and abolished detection of endogenous TGN38. These results suggest that discrete cytoplasmic determinants can mediate protein localization to the TGN, and reveal a novel role for tyrosine-based motifs in this process.

Characterization of the heterogeneity of polyethylene glycol-modified superoxide dismutase by chromatographic and electrophoretic techniques

Covalent attachment of polyethylene glycol (PEG) chains to the enzyme Cu,Zn-superoxide dismutase (SOD) produces a heterogeneous mixture of modified protein species. The heterogeneity of the product (PEG-SOD) derives from a variable stoichiometric combination of PEG with individual SOD molecules in addition to the polydispersity of the PEG reagent. Characterization of PEG-SOD presents significant challenges due in part to this heterogeneity in addition to the hybrid nature of the modified enzyme. The application of classical methods of protein characterization is not always successful for these PEG-proteins requiring the development of alternative or modified procedures. A series of chromatographic techniques including reversed-phase, ion-exchange, size-exclusion, and hydrophobic interaction high-performance liquid chromatography along with electrophoretic techniques including isoelectric focusing, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and capillary zone electrophoresis have been developed for assessing the degree of heterogeneity of PEG-SOD samples which encompass a range of different stoichiometries. Examples will be given demonstrating the application of these techniques to characterize PEG-SOD samples of different composition produced during the course of the reaction between SOD and an activated PEG reagent.

A recycling pathway between the endoplasmic reticulum and the Golgi apparatus for retention of unassembled MHC class I molecules

Assembly of class I major histocompatibility complex (MHC) molecules involves the interaction of two distinct polypeptides (the heavy and light chains) with peptide antigen. Cell lines synthesizing both chains but expressing low levels of MHC class I molecules on their surface as a result of a failure in assembly and transport have been identified. We now report that although the apparent steady-state distribution in these cells of class I molecules is in the endoplasmic reticulum (ER), the molecules in fact are recycled between the ER and Golgi, rather than retained in the ER. This explains the failure of class I molecules to negotiate the secretory pathway. Class I molecules do not seem to be modified by Golgi enzymes, suggesting that the proteins do not reach the Golgi apparatus during recycling. But morphological and subcellular fractionation evidence indicates that they pass through the cis Golgi or a Golgi-associated organelle, which we postulate to be the recycling organelle. This compartment, which we call the 'cis-Golgi network', would thereby be a sorting organelle that selects proteins for return to the ER.

Novel redistribution of an intracellular pool of CD45 accompanies T cell activation

The major tyrosine phosphatase activity against angiotensin detected in membranes of the antigen-specific T cell hybridoma 2B4 is contained in the cytoplasmic tail of the CD45 molecule. When these cells are stimulated with either an antibody directed against the T cell antigen receptor or an activating anti-Thy-1 antibody, there is a rapid redistribution of CD45 in the cells. The redistribution can be observed in two ways: morphology and subcellular fractionation. Morphologic examination of resting cells reveals intense CD45 staining of the Golgi as well as surface staining. Upon activation the Golgi is rapidly cleared of CD45. This redistribution is specific for CD45 and is not observed for an intrinsic Golgi protein, mannosidase II, or a protein traversing the secretory pathway, the T cell receptor. In activated cells, in contrast to resting cells, approximately 30% of the total cellular CD45 is precipitated either at 280 x g or at 200,000 x g through a 2.2 M sucrose cushion after cell homogenization. This fraction is not accessible to cell surface labeling. CD45 redistribution does not require hydrolysis of phosphatidylinositides and cannot be reproduced by the addition of phorbol ester and calcium ionophore. It does require the presence of an intact functional T cell receptor on the cell surface. These studies suggest that the residence time of CD45 within an intracellular organelle can be acutely regulated by a signal mediated via the T cell receptor. This regulation may control access of this phosphatase to critical substrates.

Microtubule-dependent retrograde transport of proteins into the ER in the presence of brefeldin A suggests an ER recycling pathway

Characteristics of brefeldin A (BFA)-induced redistribution of Golgi proteins into the endoplasmic reticulum (ER) and its relationship to an ER retrieval pathway were investigated. Retrograde movement of Golgi proteins into the ER occurred via long, tubulovesicular processes extending out of the Golgi along microtubules. Microtubule-disrupting agents (i.e., nocodazole), energy poisons, and reduced temperatures inhibited this pathway. In BFA-treated cells Golgi proteins appeared to cycle between the ER and an intermediate compartment marked by a 53 kd protein. Addition of nocodazole disrupted this dynamic cycle by preferentially inhibiting retrograde movement, causing Golgi proteins to accumulate in the intermediate compartment. In the absence of BFA, such an ER cycling pathway appeared to be followed normally by the 53 kd protein but not by Golgi proteins, as revealed by temperature shift experiments. We propose that BFA induces the interaction of the Golgi with an intermediate "recycling" compartment that utilizes a microtubule-dependent pathway into the ER.

Rapid redistribution of Golgi proteins into the ER in cells treated with brefeldin A: evidence for membrane cycling from Golgi to ER

In cells treated with brefeldin A (BFA), movement of newly synthesized membrane proteins from the endoplasmic reticulum (ER) to the Golgi apparatus was blocked. Surprisingly, the glycoproteins retained in the ER were rapidly processed by cis/medial Golgi enzymes but not by trans Golgi enzymes. An explanation for these observations was provided from morphological studies at both the light and electron microscopic levels using markers for the cis/medial and trans Golgi. They revealed a rapid and dramatic redistribution to the ER of components of the cis/medial but not the trans Golgi in response to treatment with BFA. Upon removal of BFA, the morphology of the Golgi apparatus was rapidly reestablished and proteins normally transported out of the ER were efficiently and rapidly sorted to their final destinations. These results suggest that BFA disrupts a dynamic membrane-recycling pathway between the ER and cis/medial Golgi, effectively blocking membrane transport out of but not back to the ER.

Selective degradation of T cell antigen receptor chains retained in a pre-Golgi compartment

We have examined the fate of newly synthesized T cell antigen receptor (TCR) subunits in a T cell hybridoma deficient in expression of the clonotypic beta chain. Synthesis and assembly of the remaining chains proceed normally but surface expression of TCR chains is undetectable in these cells. A variety of biochemical and morphological techniques has been used to show that the TCR chains in these cells fail to be transported to any of the Golgi cisternae. Instead, they are retained in a pre-Golgi compartment which is either part of or closely related to the endoplasmic reticulum. The CD3-delta chain is degraded by a non-lysosomal process that is inhibited at temperatures at or below 27 degrees C. By contrast, the remaining chains (CD3-epsilon, CD3-gamma, and zeta) are very stable over 7 h. We propose possible mechanisms that may explain the differential fate of TCR chains retained in a pre-Golgi compartment.

Degradation from the endoplasmic reticulum: disposing of newly synthesized proteins

We have characterized a pre-Golgi, proteolytic pathway for rapid degradation of newly synthesized T cell receptor (TCR) subunits which is insensitive to drugs that block lysosomal proteolysis. The site of degradation in this pathway is either part of or closely related to the endoplasmic reticulum (ER). This "ER" degradative pathway very likely plays an important role in many cells in the removal of unassembled or incompletely assembled membrane protein complexes from the secretory pathway. It is the sole pathway followed by TCR alpha chains and alpha-beta complexes in transfected fibroblasts. In T cells treated with ionophores, which disrupt transport of the TCR from the ER to the Golgi, all newly synthesized alpha, beta, and delta chains are destroyed by this pathway. A variety of biochemical and morphological techniques have been used to distinguish the "ER" degradative pathway from an alternative, lysosomal pathway.

Cortical reaction and zona hardening in mouse oocytes following exposure to ethanol

Mouse oocytes were treated with 8% ethanol for 3-6 min. The rate and pathways of parthenogenetic activation, occurrence of cortical reaction, and zona solubility changes were assessed in alcohol-treated eggs. The incidence of parthenogenetic activation was greatest (91%) after 3-4-min exposure, and it was reduced (84%) after 5-6-min exposure to alcohol. Also, the rate of haploid single pronucleate parthenogenones decreased and the rate of fragmented ova increased with increase time of exposure to ethanol. Ultrastructural observations showed occurrence of cortical reaction, disappearance and subsequent reappearance of short microvilli. A slight damage occurred to the ER in alcohol-exposed ova. The zona dissolution assay utilizing alpha-chymotrypsin demonstrated decreased solubility of the zonae pellucidae after exposure to alcohol. The zona dissolution t50 increased from 0.5-2.5 min in nontreated unfertilized oocytes to about 4 h in activated ova. The t50 of in vivo fertilized eggs was 4 1/2 h. Empty zonae exposed to alcohol lysed at the same rate as nontreated control zonae did. The results indicate that activation of mouse oocytes with alcohol initiates completion of meiosis and triggers the cortical reaction, which results in subsequent hardening of the zona pellucida.

Use of riboflavin-binding protein to investigate steric and electronic relationships in flavin analogs and models

We have examined the affinity of two recently synthesized flavin analogs for the isoalloxazine binding site of riboflavin-binding protein (RBP). The results showed that pyrimidopteridines could bind to RBP (Kd 160-250 microM). This suggested that, at the FMN or FAD level, these analogs might also bind to other apoflavoproteins, thereby providing a high potential probe for flavin enzymology. In contrast, 4a,5-ring-opened isoalloxazines did not bind to RBP. However, 1,10a-ring-opened flavins bind with considerable avidity (Kd about 40 nM). Evidence is presented which indicates that the 4a,5-ring-opened species adopted a nonplanar configuration which, in turn, was responsible for the lack of affinity to RBP. Steric and electronic consequences of a 4a,5 ring opening are discussed in relation to flavin-dependent phenolic hydroxylases.

Identification of mammalian sperm surface antigens: II. Characterization of an acrosomal cap protein and a tail protein using monoclonal anti-mouse sperm antibodies

Monoclonal anti-mouse sperm antibodies have been produced by fusing mouse myeloma cells with spleen cells from rats immunized with epididymal sperm of C3H mice, Immunoprecipitation and immunoperoxidase techniques showed that one such monoclonal antibody, AMS IV-33, recognized a 200 000 dalton protein localized on the acrosomal cap of the sperm cell. Two other monoclonal antibodies AMS IV-54 and -76, reacted with a 68 000 dalton component on the surface of the sperm tail. Both antigenic targets were species specific and were present in about equal amounts on sperm from several different strains of mice. The tail protein was sperm specific, whereas the antibody reacting with the acrosomal cap protein also appeared to react somewhat with antigens present in other mouse tissues.

Identification of mammalian sperm surface antigens. I. Production of monoclonal anti-mouse sperm antibodies

Surface antigens of mammalian sperm were studied by use of monoclonal antibodies (MAs). Six hybridoma cell lines were obtained by fusion of mouse myeloma cells with spleen cells from rats immunized with unwashed, epididymal sperm from C3H mice. Quantitative assessment of antibody binding, using a solid phase, antibody-protein A assay, indicated that four MAs bound to integral, sperm surface antigens; two others bound to nonintegral sperm antigens or epididymal fluid components. Immunofluorescence studies showed specific binding of individual MAs to localized regions: acrosome, midpiece, and midpiece and tail. All of these MAs inhibited sperm-egg binding, and those to the midpiece and/or tail immobilized sperm cells. The monoclonal antibodies provide probes for immunochemical characterization of sperm antigens and for elucidation of the role of the antigens in sperm.

An improved method for processing single cells for electron microscopy utilizing agarose

An improved method is presented for processing single cells for electron microscopy. Agarose, which has a low (30 degrees C) gelling temperature, was used as an initial embedding medium for single cells (spermatozoa and oocytes) and dissociated cell preparations (luteal cells and spleen cells). Dispersed cells of corpus luteum, spleen, and epididymal spermatozoa were placed in 1.5% agarose after aldehyde fixation. These fixed cells, embedded in agarose, were packed into a dense pellet by centrifugation, postfixed, then embedded in Epon. Mammalian eggs were not centrifuged; instead, they were embedded in agarose discs. Cells embedded in agarose were cooled below 30 degrees C to allow for gelling, then processed for electron microscopy. Because agarose has a low gelling temperature, some heat-labile substances were preserved, as demonstrated by retention of peroxidase activity using the DAB histochemical method. The agarose embedding procedure is both rapid and facile, and has proven to be of value in the handling of fragile single cells for electron microscopic studies.

Progesterone production by dispersed monkey (Macaca mulatta) luteal cells after exposure to trypsin

In an attempt to justify use of trypsin to achieve more thorough dispersion of luteal cell clumps in vitro, progesterone (P) production by collagenase dispersed monkey luteal cells from the mid-luteal phase corpus luteum (CL) was examined in vitro either after 10 min, or continuous (3h) exposure to trypsin (TR). In the first experiment, cells were pre-incubated in TR, then incubated at 37 degrees C for 3h with human chorionic gonadotropin (hCG) after the addition of soybean-trypsin inhibitor (STI). Pre-incubation of luteal cells with TR had no effect on the level of P production under basal conditions. Cells that were preincubated with TR responded to hCG stimulation with increased progesterone secretion (P less than 0.01) in a fashion similar to untreated cells. P production in response to hCG was independent of TR concentration over the range of 0.05% to 0.2% during the pre-incubation period. However, continuous exposure (3h) of cells to TR significantly depressed (P less than 0.01) basal P secretion and inhibited the response to hCG. We conclude that TR had no effect on the biopotency of hCG per se, but probably the over-exposure to TR had an adverse effect on the LH/hCG receptors. Addition of STI after a 10 min pre-incubation with TR, prevented these deliterious effects, thereby permitting the use of TR to improve the completeness of luteal cell dissociation.

Association of microperoxisomes with the endoplasmic reticulum in the granulosa lutein cells of the Rhesus monkey (Macaca mulatta)

Aldehyde fixed tissue from monkey (Macaca mulatta) corpus luteum was incubated in alkaline 3,3inch-diaminobenzidine (DAB), and prepared for electron microscopic histochemical observations. The association of microperoxisomes with the granular (GER) or agranular (AER) endoplasmic reticulum was reconstructed from serially sectioned tissues and by tilting of specimens in the microscope. Out of 107 microperoxisomes, 106 were directly associated with the AER. Two different forms of attachment were found between microperoxisomes and the AER and that of the microperoxisome are confluent. In the second, lingulate type of connection, a blunt-end structure either is inserted into an invagination of the AER, or penetrates into the lumen of the AER. The lumen of the lingula is confluent with the microperoxisome, but not with the AER. In addition to these connections, fine thread-like structures were observed extending between AER and adjacent microperoxisomes.

Microperoxisomes in the late pregnancy corpus luteum of rhesus monkeys (Macaca mulatta)

Microperoxisomes were identified in the franulosa lutein cells from the corpora lutea of rhesus monkeys (Macaca mulatta). These organelles were histochemically visualized in aldehyde-fixed tissues icubated in alkaline 3,3'-diaminobenzidine (DAB). The DAB staining of the microperoxisomes was abolished when the tissues were preincubated in specific inhibitors for catalse or when the H2O2 was omitted from the DAB medium. Microperoxisomes were differentiated from primary lysosmes by the Gomori acid phosphatase staining. Tortuous undulating agranular endoplasmic reticulum (ER) was usually closely associated with microperoxisomes. Those regions of the granular ER which were closely associated with microperoxosomes lacked ribsomes. Micropersoxisomes were often contiguous with lipid droplets, and in some instances the limiting membrane of the moroperosisomes appeared discontinous at the point of contiguity, and the DAB staining substance diffused onto the surface of the lipid droplet. In these instances, the adjacent area of the lipid droplet showed electron-lucent staining.

Detection of relativistic particles

It appears possible to extend the application of most of the existing detection techniques to the identification and separation of charged particles in the relativistic energy region.One can probably extend these applications, in certain limited cases, up to an energy region of several hundred billion electron volts. However, for general applications in the identification of particles in the ultrarelativistic region, the existing detectors are rather limited, and new methods and approaches are desirable. At present, detectors making use of the relativistic rise effect seem to show considerable promise.