Synthesis of thermally stable SBT and SBS/SBT intergrowth zeolites.

UCSB-6 (framework type SBS) and UCSB-10 (SBT), two three-dimensional phosphate-based molecular sieves with supercages accessible through 12-ring (circumscribed by 12 tetrahedral atoms) windows, are structurally similar to the hexagonal and cubic polytypes of faujasite or zeolite Y, an industrially relevant catalyst, but the cage structures are substantially different. Nonetheless, their inherent thermal instability has precluded any catalytic application so far. By using multiple inorganic cation and charge density mismatch approaches, we synthesized PST-32 and PST-2, a thermally stable aluminosilicate version of UCSB-10 and the hypothetical SBS/SBT intergrowth family member, respectively. This study suggests that many hypothetical cage-based zeolite structures with multidimensional channel systems can be synthesized as compositionally robust forms by systematically exploring the synergy effect of inorganic and organic structure-directing agents.

Increased Bolus Volume Effect on Delayed Pharyngeal Swallowing Response in Post-stroke Oropharyngeal Dysphagia: A Pilot Study.

OBJECTIVE: To confirm a relationship between the pharyngeal response and bolus volume, and examine whether increasing the fluid bolus volume can improve penetration and aspiration for stroke dysphagic patients. METHODS: Ten stroke patients with a delayed pharyngeal response problem confirmed by a videofluoroscopic swallowing study (VFSS) were enrolled. Each subject completed two swallows each of 2 mL, 5 mL, and 10 mL of barium liquid thinned with water. The pharyngeal delay time (PDT) and penetration-aspiration scale (PAS) were measured and the changes among the different volumes were analyzed. RESULTS: PDTs were shortened significantly when 5 mL and 10 mL of thin barium were swallowed compared to 2 mL. However, there was no significant difference in PAS as the bolus volume increased. CONCLUSION: The increased fluid bolus volume reduced the pharyngeal delay time, but did not affect the penetration and aspiration status.

Micromorphology and development of the epicuticular structure on the epidermal cell of ginseng leaves.

BACKGROUND: A leaf cuticle has different structures and functions as a barrier to water loss and as protection from various environmental stressors. METHODS: Leaves of Panax ginseng were examined by scanning electron microscopy and transmission electron microscopy to investigate the characteristics and development of the epicuticular structure. RESULTS: Along the epidermal wall surface, the uniformly protuberant fine structure was on the adaxial surface of the cuticle. This epicuticular structure was highly wrinkled and radially extended to the marginal region of epidermal cells. The cuticle at the protuberant positions maintained the same thickness. The density of the wall matrix under the structures was also similar to that of the other wall region. By contrast, none of this structure was distributed on the abaxial surface, except in the region of the stoma. During the early developmental phase of the epicuticular structure, small vesicles appeared on wall-cuticle interface in the peripheral wall of epidermal cells. Some electron-opaque vesicles adjacent to the cuticle were fused and formed the cuticle layer, whereas electron-translucent vesicles contacted each other and progressively increased in size within the epidermal wall. CONCLUSION: The outwardly projected cuticle and epidermal cell wall (i.e., an epicuticular wrinkle) acts as a major barrier to block out sunlight in ginseng leaves. The small vesicles in the peripheral region of epidermal cells may suppress the cuticle and parts of epidermal wall, push it upward, and consequently contribute to the formation of the epicuticular structure.

Myosin-binding protein C corrects an intrinsic inhomogeneity in cardiac excitation-contraction coupling.

The beating heart exhibits remarkable contractile fidelity over a lifetime, which reflects the tight coupling of electrical, chemical, and mechanical elements within the sarcomere, the elementary contractile unit. On a beat-to-beat basis, calcium is released from the ends of the sarcomere and must diffuse toward the sarcomere center to fully activate the myosin- and actin-based contractile proteins. The resultant spatial and temporal gradient in free calcium across the sarcomere should lead to nonuniform and inefficient activation of contraction. We show that myosin-binding protein C (MyBP-C), through its positioning on the myosin thick filaments, corrects this nonuniformity in calcium activation by exquisitely sensitizing the contractile apparatus to calcium in a manner that precisely counterbalances the calcium gradient. Thus, the presence and correct localization of MyBP-C within the sarcomere is critically important for normal cardiac function, and any disturbance of MyBP-C localization or function will contribute to the consequent cardiac pathologies.

Orientation of myosin binding protein C in the cardiac muscle sarcomere determined by domain-specific immuno-EM.

Myosin binding protein C is a thick filament protein of vertebrate striated muscle. The cardiac isoform [cardiac myosin binding protein C (cMyBP-C)] is essential for normal cardiac function, and mutations in cMyBP-C cause cardiac muscle disease. The rod-shaped molecule is composed primarily of 11 immunoglobulin- or fibronectin-like domains and is located at nine sites, 43nm apart, in each half of the A-band. To understand how cMyBP-C functions, it is important to know its structural organization in the sarcomere, as this will affect its ability to interact with other sarcomeric proteins. Several models, in which cMyBP-C wraps around, extends radially from, or runs axially along the thick filament, have been proposed. Our goal was to define cMyBP-C orientation by determining the relative axial positions of different cMyBP-C domains. Immuno-electron microscopy was performed using mouse cardiac myofibrils labeled with antibodies specific to the N- and C-terminal domains and to the middle of cMyBP-C. Antibodies to all regions of the molecule, except the C-terminus, labeled at the same nine axial positions in each half A-band, consistent with a circumferential and/or radial rather than an axial orientation of the bulk of the molecule. The C-terminal antibody stripes were slightly displaced axially, demonstrating an axial orientation of the C-terminal three domains, with the C-terminus closer to the M-line. These results, combined with previous studies, suggest that the C-terminal domains of cMyBP-C run along the thick filament surface, while the N-terminus extends toward neighboring thin filaments. This organization provides a structural framework for understanding cMyBP-C's modulation of cardiac muscle contraction.

Cardiac myosin binding protein-C plays no regulatory role in skeletal muscle structure and function.

Myosin binding protein-C (MyBP-C) exists in three major isoforms: slow skeletal, fast skeletal, and cardiac. While cardiac MyBP-C (cMyBP-C) expression is restricted to the heart in the adult, it is transiently expressed in neonatal stages of some skeletal muscles. However, it is unclear whether this expression is necessary for the proper development and function of skeletal muscle. Our aim was to determine whether the absence of cMyBP-C alters the structure, function, or MyBP-C isoform expression in adult skeletal muscle using a cMyBP-C null mouse model (cMyBP-C((t/t))). Slow MyBP-C was expressed in both slow and fast skeletal muscles, whereas fast MyBP-C was mostly restricted to fast skeletal muscles. Expression of these isoforms was unaffected in skeletal muscle from cMyBP-C((t/t)) mice. Slow and fast skeletal muscles in cMyBP-C((t/t)) mice showed no histological or ultrastructural changes in comparison to the wild-type control. In addition, slow muscle twitch, tetanus tension, and susceptibility to injury were all similar to the wild-type controls. Interestingly, fMyBP-C expression was significantly increased in the cMyBP-C((t/t)) hearts undergoing severe dilated cardiomyopathy, though this does not seem to prevent dysfunction. Additionally, expression of both slow and fast isoforms was increased in myopathic skeletal muscles. Our data demonstrate that i) MyBP-C isoforms are differentially regulated in both cardiac and skeletal muscles, ii) cMyBP-C is dispensable for the development of skeletal muscle with no functional or structural consequences in the adult myocyte, and iii) skeletal isoforms can transcomplement in the heart in the absence of cMyBP-C.

Acute respiratory failure associated with cryptococcal pneumonia and disseminated cryptococcosis in an AIDS patient.

A 36-year-old homosexual Mexican man was admitted to our hospital, with a 30-day history of fever and headache. Upon cerebrospinal fluid examination, the patient's white blood cell count was 1,580/L, total protein was 26 mg/dL, sugar was 17 mg/dL, and his intracranial pressure was 23 cmH2O. The patient was diagnosed with HIV (Human Immunodeficiency Virus) infection by serum Western blotting. Cryptococcus neoformans was isolated in cultures of the patient's blood and cerebrospinal fluids. Chest computerized tomography revealed diffuse reticulonodular infiltration and a ground-glass appearance in both perihilar regions, suggestive of either Pneumocystis carinii pneumonia or cryptococcal pneumonia. On the patient's 6th day in our hospital, bronchoalveolar lavage and transbronchial lung biopsy were conducted via bronchoscopy, and a pathologic examination of lung biopsy specimens revealed signs of cryptococcal pneumonia. This patient died on his 14th day in our hospital, as the result of acute respiratory failure, associated with cryptococcal pneumonia and disseminated cryptococcosis.

Hypersensitivity reactions to oxaliplatin.

Oxaliplatin is a third-generation platinum compound that is used as a single agent and in combination with fluorouracil (5-FU) to treat colorectal and gastric carcinoma. The patients treated with oxaliplatin may develop hypersensitivity and idiosyncratic reactions, although these complications are known to be rare. We report here on two patients who suffered with metastatic colorectal cancer and who underwent palliative combination chemotherapy with oxaliplatin; they then developed hypersensitivity reactions to oxaliplatin. The first case had an anaphylatic reaction immediately after the beginning of the 7(th) to 8(th) cycle infusion of oxaliplatin. The second case developed repeated febrile episodes from the 4(th) to 8(th) cycles of oxaliplatin infusion. With the increasing use of oxaliplatin in clinical practice, we are now encountering an increasing incidence of suspected hypersensitivity reactions. Physicians should keep their eyes wide open and carefully observe for the clinical manifestations of these hypersensitivity reactions.