Direct Measurement of the Density Matrix of a Quantum System.

One drawback of conventional quantum state tomography is that it does not readily provide access to single density matrix elements since it requires a global reconstruction. Here, we experimentally demonstrate a scheme that can be used to directly measure individual density matrix elements of general quantum states. The scheme relies on measuring a sequence of three observables, each complementary to the last. The first two measurements are made weak to minimize the disturbance they cause to the state, while the final measurement is strong. We perform this joint measurement on polarized photons in pure and mixed states to directly measure their density matrix. The weak measurements are achieved using two walk-off crystals, each inducing a polarization-dependent spatial shift that couples the spatial and polarization degrees of freedom of the photons. This direct measurement method provides an operational meaning to the density matrix and promises to be especially useful for large dimensional states.

Masseter function and skeletal malocclusion.

The aim of this work is to review the relationship between the function of the masseter muscle and the occurrence of malocclusions. An analysis was made of the masseter muscle samples from subjects who underwent mandibular osteotomies. The size and proportion of type-II fibers (fast) decreases as facial height increases. Patients with mandibular asymmetry have more type-II fibers on the side of their deviation. The insulin-like growth factor and myostatin are expressed differently depending on the sex and fiber diameter. These differences in the distribution of fiber types and gene expression of this growth factor may be involved in long-term postoperative stability and require additional investigations. Muscle strength and bone length are two genetically determined factors in facial growth. Myosin 1H (MYOH1) is associated with prognathia in Caucasians. As future objectives, we propose to characterize genetic variations using "Genome Wide Association Studies" data and their relationships with malocclusions.

Abundant expression of myosin heavy-chain IIB RNA in a subset of human masseter muscle fibres.

Type IIB fast fibres are typically demonstrated in human skeletal muscle by histochemical staining for the ATPase activity of myosin heavy-chain (MyHC) isoforms. However, the monoclonal antibody specific for the mammalian IIB isoform does not detect MyHC IIB protein in man and MyHC IIX RNA is found in histochemically identified IIB fibres, suggesting that the IIB protein isoform may not be present in man; if this is not so, jaw-closing muscles, which express a diversity of isoforms, are likely candidates for their presence. ATPase histochemistry, immunohistochemistry polyacrylamide gel electrophoresis and in situ hybridization, which included a MyHC IIB-specific mRNA riboprobe, were used to compare the composition and RNA expression of MyHC isoforms in a human jaw-closing muscle, the masseter, an upper limb muscle, the triceps, an abdominal muscle, the external oblique, and a lower limb muscle, the gastrocnemius. The external oblique contained a mixture of histochemically defined type I, IIA and IIB fibres distributed in a mosaic pattern, while the triceps and gastrocnemius contained only type I and IIA fibres. Typical of limb muscle fibres, the MyHC I-specific mRNA probes hybridized with histochemically defined type I fibres, the IIA-specific probes with type IIA fibres and the IIX-specific probes with type IIB fibres. The MyHC IIB mRNA probe hybridized only with a few histochemically defined type I fibres in the sample from the external oblique; in addition to this IIB message, these fibres also expressed RNAs for MyHC I, IIA and IIX. MyHC IIB RNA was abundantly expressed in histochemical and immunohistochemical type IIA fibres of the masseter, together with transcripts for IIA and in some cases IIX. No MyHC IIB protein was detected in fibres and extracts of either the external oblique or masseter by immunohistochemistry, immunoblotting and electrophoresis. Thus, IIB RNA, but not protein, was found in the fibres of two different human skeletal muscles. It is believed this is the first report of the substantial expression of IIB mRNA in man as demonstrated in a subset of masseter fibres, but rarely in limb muscle, and in only a few fibres of the external oblique. These findings provide further evidence for the complexity of myosin gene expression, especially in jaw-closing muscles.

Differential effects of diminished oestrogen and androgen levels on development of skeletal muscle fibres in hypogonadal mice.

Androgen and oestrogen hormones influence skeletal muscle size and the characteristics of skeletal muscle fibre types. These effects have typically been assessed by producing acute shortages (castration/ovariectomy) or by hormone supplementation. Little evidence exists, however, on how sex hormone shortages affect muscle development from early stages through to adulthood. Using the hypogonadal mouse model (hpg) we examined the effects of diminished androgen and oestrogen upon muscle size and fibre type composition in murine gastrocnemius and soleus muscles. Hypogonadal male soleus muscle was significantly smaller than normal males, and approximated the normal and hypogonadal females weight and fibre type characteristics. The hypogonadal male gastrocnemius muscle, however, was significantly small in comparison with normal and hypogonadal female gastrocnemius muscles, with the type IIB fibre diameters decreased most markedly. The hypogonadal female soleus muscle approximated the normal female phenotype, but the gastrocnemius muscle was larger than the normal female, approximating the size of the normal male gastrocnemius muscle. Here too, the type IIB fibres showed the most alteration, with greatly increased fibre diameters. Appropriate amounts of androgens were necessary for gender-specific patterns of growth in male muscles, whilst similar amounts of oestrogen were necessary for female gastrocnemius muscle growth, but not for female soleus muscle. Hypogonadism in this murine model generally retards muscle development in males, but has no apparent influence or enhances muscle development in females. Type IIB fibres are most dependent upon sex hormones for appropriate development, but this relationship is muscle-specific.

Maximum shortening velocity and myosin heavy-chain isoform expression in human masseter muscle fibers.

While human masseter muscle is known to have unusual co-expression of myosin heavy-chain proteins, cellular kinetics of individual fibers has not yet been tested. Here we examine if myosin heavy-chain protein content is closely correlated to fiber-shortening speed, as previously reported in other human muscles, or if these proteins do not correlate well to shortening speeds, as has been demonstrated previously in rat muscle. Slack-test recordings of single, skinned human masseter fibers at 15 degrees C revealed maximum shortening velocities generally slower and much more variable than those recorded in human limb muscle. The slowest fiber recorded had a maximum shortening velocity (V0) value of 0.027 muscle lengths x s(-1), several times slower than the slowest type I fibers previously measured in humans. By contrast, human limb muscle controls produced V0 measurements comparable with previously published results. Analysis by gel electrophoresis found 63% of masseter fibers to contain pure type I MyHC and the remainder to co-express mostly type I in various combinations with IIA and IIX isoforms. V0 in masseter fibers forms a continuum in which no clear relationship to MyHC isoform content is apparent.

Rat seminal-vesicle secretory protein SVS II binds DNA with a preference for the 5' regulatory region of secretory protein SVS IV gene: co-isolation with components of the nuclear matrix.

In rats, the ventral prostate and seminal vesicles produce distinct sets of proteins whose functions and tissue-specific regulation by androgens remain unclear. We have utilized the genes encoding the major secretory protein of seminal vesicles, SVS IV, and the C3 subunit of prostatein of the ventral prostate to study how the nuclear matrix might determine their tissue-specific gene expression. Nuclear matrix proteins were prepared from purified nuclei with DNase and 2 M NaCl, separated in SDS gels, and transferred onto membranes for DNA-binding (southwestern) and immunological (western) analyses. The 5' region of the SVS IV gene (SVS IV-7S) bound to a 45,000-kDa molecular-weight protein band in the nuclear matrix of seminal vesicles but not to that of ventral prostate, kidney, or liver. Sequencing revealed that this band was a seminal-vesicle secretory protein, SVS II, whose identity was confirmed with an anti-SVS II antiserum in western blots. Actin-like protein, similar in mobility to SVS II, was detected in seminal-vesicle and ventral prostate nuclear matrix, but not in seminal-vesicle fluid. Reducing agent (10 mM dithiothreitol) and acidic (pH 6.5) buffer did not eliminate SVS II, but isolation of nuclear matrices with ammonium sulfate, nucleases, and urea decreased SVS II immunoreactivity and removed actin-like protein. SVS II binding to SVS IV-7S DNA was greater than its binding to either a comparable fragment of the C3 gene or linearized pUC-19 plasmid, and it was not eliminated by a 100-fold competition. When seminal-vesicle fluid was mixed with rat liver, some SVS II co-isolated with the nuclear-matrix proteins, indicating that nonspecific interactions contribute to its association with the nucleoskeleton. However, these interactions may not represent the intracellular behavior of SVS II in seminal-vesicle epithelium. Sequence comparisons indicate significant homologies between SVS II and some other seminal proteins, including bovine caltrin, which, under the name seminalplasmin, is known to possess antimicrobial activity. Collectively, these data suggest that in addition to its known functions, SVS II may also bind extraneous DNA in seminal fluid. Additionally, SVS II may participate as a structural component in the organization of a tissue-specific seminal-vesicle nuclear matrix.

Monoclonal antibody toward lysosomal cathepsin B cross-reacts preferentially with distinct histone classes.

1. A set of monoclonal antibodies (Mab) was prepared against cathepsin B (CB) from rat preputial-gland, an organ characterized by rapidly-renewing cell populations, which is a uniquely enriched source of lysosomal enzymes, including CB. Minute amounts of CB are known to be transferred abruptly to the nuclear compartment in a variety of activated cells. 2. Since, on the basis of its stringent substrate requirements, CB was expected to function at limited protein loci in chromatin, Mab Line II-B4 was used to probe Western blots of chromatin fractions and selected proteins. 3. The Mab, which was not directed against the active site of CB, cross-reacted preferentially with histones 3 and 4 (H3 and H4) in acid-soluble fractions of chromatin from rat preputial-gland. Line II-B4 also recognized H3 and H4 selectively in calf thymus histones and among histones purified from a wide range of sources from yeast to man. HMG 1 was minimally immunoreactive among preputial gland constituents and carbonic anhydrase (CA) was also sensitive to the Mab. 4. The common determinants were not shared by any of the H1 series, nor by H2A, H2B, protein A24 or a wide range of natural and synthetic products. 5. Origin of the antigenicity was traced by chemical modifications of H3, H4 and CA to the critical contribution of arginine and hydrophobic amino acid residues in its immediate environment, indicating that Line II-B4 may be directed against an epitope comprising the specific binding-site of CB and its selective substrate(s). 6. These data suggest that certain highly conserved cellular constituents may be uniquely vulnerable to limited proteolysis in preproliferative cells responding to mitotic signals.

Nuclease resistance and the enrichment of native nuclear acceptor sites for the avian oviduct progesterone receptor.

High-affinity nucleoprotein acceptor sites for the avian oviduct progesterone receptor (PR) have been enriched by a combination of nuclease digestion and centrifugation. These enriched binding elements exhibited markedly enhanced PR binding on a per mass DNA basis compared to chromatin (20- to 25-fold) or dehistonized chromatin (4- to 5-fold). Electrophoretic analysis of the nuclease-resistant DNA showed that there is a set of DNA fragments of 100-150 base pairs that are protected from digestion. Excessive digestion resulted in smaller DNA fragments and a loss of PR binding activity. The PR binding was saturable using a crude receptor preparation and displayed a competition with the same receptor preparation that was labeled with nonradioactive progesterone. The enhanced binding was also demonstrable using highly purified receptor preparations that exhibit two classes of binding sites both of which are of high affinity and saturable as assessed by Scatchard analyses. These two high-affinity classes of binding sites are shown to be competed by unlabeled purified PR. The nuclease resistance of these nucleoprotein acceptor sites from chromatin is a property similar to the nuclear matrix binding sites suggesting a relationship between these two classes of nuclear acceptor sites.

Chromatin proteins of rat preputial-gland: acute changes in response to estrogen.

The effects of estradiol-17 beta (E2 beta) at 2 or 15 min in vivo on chromatin proteins of rat preputial-gland were analyzed by a battery of electrophoretic methods. Among histones, E2 beta/control ratios for major bands of H1 decreased substantially between 2 and 15 min. In contrast, ratios of H4 increased (P less than 0.01), whereas, except for losses by 2 min in a H2B-like component and in H3.1, other core histones were unchanged. Among 0.35 M NaCl-soluble proteins, components at 34K-mol. wt and less than 21K -mol wt were increased after 2 min of E2 beta. The bulk of the hormone-responsive low-molecular weight proteins was basic in charge. Electrophoretic correlates of 6 basic lysosomal proteins corresponded to those of low-molecular weight salt-soluble chromatin proteins. Selective proteolysis initiated in vivo by E2 beta depleted some tightly-bound nonhistone proteins.

Antibodies against estradiol-binding lysosomal lipoproteins gain access to the nuclear compartment of preputial gland cells under estrogen influence.

The influence of estrogen in provoking nuclear recompartmentation of lysosomal components in hormone-sensitive cells was investigated by immunological analyses of isolated nuclei from the preputial glands of ovariectomized rats. Fixed smears were prepared from ultrapurified nuclei freed of outer membrane, 2-30 min after iv injection of placebo-control solution or submicrogram amounts of estradiol-17 beta. Cytoplasmic contamination was negligible in such preparations, as monitored by vital staining with acridine orange. On challenge with immunoglobulin G directed toward a group of lysosomal high density lipoproteins which have been shown to bind estradiol-17 beta specifically, control preparations exhibited minimal indirect immunofluorescence that was essentially confined to the nuclear periphery. In contrast, a high proportion of the nuclei exposed for as little as 2 min to estradiol-17 beta but not to the relatively inert 17 alpha-congener, displayed generally more intense immunofluorescence which was distributed over the entire organellar area. Thus, the immunoglobulin becomes accessible to the nuclear interior in vitro as a function of pretreatment in vivo with active hormone. Nuclei from estrogen-pretreated rats were more structurally labile than corresponding controls, as judged by morphological criteria, even when isolated by gentle teasing rather than subjection to the rigorous ultrapurification process. By either method, integrity of the specimens was enhanced somewhat when they were prepared from rats ovariectomized before experiencing even a single estrous cycle. The observations verify and extend independent biochemical and ultrastructural evidence that structural labilization of cellular organelles and enhanced accessibility of limited amounts of lysosomal constituents to the nuclear compartment of specific target cells are early correlates of estrogen action.