Invasive group A streptococcal disease in Taiwan is not associated with the presence of streptococcal pyrogenic exotoxin genes

We reviewed the clinical features of 44 patients with invasive group A streptococcal (GAS) disease who were treated at two teaching hospitals in southern Taiwan from 1991 to 1994. Genes encoding streptococcal pyrogenic exotoxin types A (speA), B (speB), C (speC), and F (speF) and serotypes of M1, M6, and M12 were determined by polymerase chain reaction to target specific sequences in the 44 isolates recovered from these patients and in 28 isolates recovered from upper respiratory sites in 28 additional patients during the study period. The protease activity of these isolates was tested by using the casein plate method. Of the 44 patients with invasive diseases, 25 (57%) had no obvious underlying diseases, and 14 (32%) had preexisting neoplastic diseases or had previously used steroids. Twenty-five patients (57%) presented with cellulitis or necrotizing fasciitis, 24 (55%) had bacteremia, and eight (18%) had streptococcal toxic shock syndrome (STSS). Eight patients (18%) died of invasive GAS disease; seven had STSS, and seven had underlying diseases. All eight patients died within 48 hours after hospitalization. The presence of speA, speC, or speF was not implicated in any particular clinical syndrome in patients with invasive GAS disease. High-level protease activity and the M1 serotype of the isolates were significantly associated with the clinical signs of STSS and with mortality. M1 serotype and protease activity, as well as host immune status, might play significant roles in the pathogenesis of invasive GAS disease in Taiwan.     

The 30-minute (1-24)ACTH test for evaluation of adrenocortical function in childhood

Twenty-eight children with normal adrenocortical function and two patients with adrenocortical insufficiency were enrolled in the present study. The ACTH test was performed in these 30 children, and the insulin hypoglycemia test was also performed for the same group, except for one with Addison's disease. Serum cortisol response after intravenous administration of (1-24)ACTH was below normal range in two patients with adrenocortical insufficiency. Neither significant correlation nor statistically significant difference was found between the serum cortisol level 30 minutes after (1-24)ACTH and the peak cortisol value during the insulin hypoglycemia test. None of these children had any adverse reaction to ACTH test. This study suggests that the 30-minute (1-24)ACTH test is a simple, safe and valuable screening procedure for evaluation of adrenocortical function in children.     

Calculation of the stress intensity factor for arbitrary finite cracked body by using the boundary weight function method

The state of thermal stresses for a periodic two-layered elastic space weakened by an interface thermally insulated Griffith crack and loaded by concentrated line heat sources is investigated. The analysis is performed within the framework of the homogenized model with microlocal parameters. The stress intensity factors at the crack tips are determined. Two examples of the application of the results obtained are detailed.     

GaAs-GaAlAs heterostructure single-mode channel-waveguide cutoff modulator and modulator array

A GaAs single-mode channel-waveguide cutoff modulator that utilizes a GaAs-GaAlAs heterostructure and a linear array of such modulators are reported for the first time. We have measured a cutoff voltage as low as 9.0 V and an extinction ratio greater than 20 dB at an optical wavelength of 1.3 μm in a basic modulator that utilized a GaAs-Ga0.93Al0.07As heterostructure with a 0.9 μm thick GaAs epitaxial layer together with a ridge channel 2.5 mm in length and 5.0 μm in width. We have also succeeded in the realization of a high packing density (500 channels/cm) linear array of such cutoff modulators in the same GaAs substrate with equally satisfactory results. An RF bandwidth of 2.5 GHz has also been measured with the elementary modulator of such array. As in the case for LiNbO3substrates, the GaAs-based integrated optic modules that result from integration of such cutoff modulator arrays, microlens arrays, and planar acoustooptic or electrooptic Bragg diffraction grating arrays in a common substrate may be used to perform multiport switching, computing, and RF signal processing.     

Structure of d(GT)n.d(GA)n sequences: formation of parallel stranded duplex DNA

Alternating polypurine sequences exhibit remarkable polymorphism. In this study, we report that dGA.dGT sequences form parallel stranded duplex DNA at neutral pH. Using two model hairpins, 3'-d(GT)3-5'5'-T4(AG)3-3' (I) and 3'-d(GT)4-5'5'-T4(AG)4-3' (II), containing 5'5' linkages which direct parallel strand formation, we systematically explored the spectroscopic and thermodynamic properties of parallel stranded d(GA)n.d(GT)n. The parallel stranded hairpins are remarkably stable structures with TM's of 41.5 and 47.5 degreesC (in 0.4 M NaCl) for the shorter and longer hairpins, respectively. The van't Hoff enthalpies of 80.7 and 114 kJ mol-1 are relatively low but are comparable to a parallel stranded d(GA)n duplex. On the basis of the spectroscopic and electrophoretic characteristics, we conclude that parallel strand formation is not restricted to hairpin systems, but also readily occurs in unconstrained dimeric duplexes with the appropriate sequence homologies. Both melting curves and electrophoretic analyses of parallel stranded heteroduplexes in which the sequence enforces specific base pairing demonstrate that G-G and A-T base pairs are formed in d(GA)n.d(GT)n segments.     

Perioperative specific management of blood volume loss in craniosynostosis surgery

Accurate assessment and replacement of blood loss and fluid-electrolyte deficit during craniosynostosis repair is difficult owing to patient size and the diversity of surgical technique. Forty-three patients undergoing primary craniosynostosis repair over a 10-year period were studied retrospectively to determine blood loss and fluid deficit and to assess blood transfusion practices during both intraoperative and postoperative periods. Blood loss was calculated on the basis of estimated red cell mass (ERCM) and fluid-electrolyte imbalance was investigated with blood samplings. Blood transfusion was considered appropriate if the postoperative or posttransfusion ERCM was within 12% of the preoperative value. Estimated fluid requirement (EFR) was used in 4 ml kg(-1) h(-1) except for neonates. Intraoperatively, 80% of all patients were appropriately managed with respect to blood transfusion and EFR. Postoperatively only 20% of the patients receiving transfusions were transfused appropriately. In 23.3% of these patients (10/43) unexpected respiratory distress developed immediately after their recovery from the anesthesia. With the measurement of estimated blood volume and allowable blood loss, appropriate transfusion could be achieved for the successful treatment of the primary craniosynostosis.     

Immunological mimicry between retinal S-antigen and group A streptococcal M proteins

Immunological mimicry between host and microbial proteins has been suggested as a potential mechanism in the development of uveitis in humans. In this study immunological crossreactivity between anti-streptococcal monoclonal antibodies (MAbs) and the human eye was investigated. In indirect immunofluorescence, we demonstrated novel immunological crossreactivity of two anti-streptococcal MAbs (27 and 112) with the rod outer (and inner) segments of the retina of the human eye. In further studies, retinal S-Ag, a uveitogenic protein in the rod outer (and inner) segments, was found to react with the anti-streptococcal MAbs. In addition, several uveitogenic peptides of S-Ag were recognized by the anti-streptococcal MAbs. In the ELISA and Western immunoblot, anti-S-Ag MAbs crossreacted with group A streptococci and the streptococcal M protein further demonstrating sites of antigenic similarity. Homology between the retinal S-Ag and streptococcal M protein was observed in amino acid sequences repeated in the B repeat region of the streptococcal M5 protein. These data show that retinal S-antigen has immunological similarities with streptococcal M protein, a major virulence determinant and strong bacterial cell surface antigen.     

A new process of fabricating inverted-staggered tri-layer thin-filmtransistors

A new method of fabricating a-Si:H TFT with etching-stop structure has been proposed. Only one plasma-enhanced chemical vapor deposition is required in this new method and a PH₃/H₂ plasma treatment during the deposition has been used to form the TFT contact and thus saved another plasma deposition. With this method, a TFT of 500 Å active layer has been fabricated successfully. The drain current and saturation mobility of this device is 2.4×10^-7 A and 0.1 cm²/V sec, respectively, which is comparable to the conventional fabricating method. The plasma treatment will also form an additional leakage path on the TFT top surface and increase the TFT subthreshold slope. However, a current of less than 1 pA at V_G=-2.4 V can still be obtained. The possible mechanism of the contact formation by the plasma treatment is also discussed     

Medical conditions of the puerperium

The puerperium is a time of continued, dramatic pregnancy-associated adaptation. Although much less common than in the early part of the century, maternal death can still occur from common postpartum problems such as infection, hemorrhage, and disease. This article reviews the physiologic and emotional changes as well as the clinical management of common problems in the puerperium.     

Retinoic acid and interferon alpha act synergistically as antiangiogenic and antitumor agents against human head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is an aggressive malignancy in which multiple independent lesions develop over time throughout the mucosa of the upper aerodigestive tract. Therefore, the comprehensive treatment of this neoplasm must include a chemopreventive arm to hold premalignant lesions in check, a role well-suited to antiangiogenic agents. Retinoic acid (RA) and interferon alpha (IFN-alpha), drugs with known biological activity against HNSCC when used individually, are also inhibitors of angiogenesis. Here we show that they are remarkably synergistic antiangiogenic agents able to inhibit both the growth and the neovascularization of HNSCC injected into the floor of the mouth of nude mice. The mechanism of action of these drugs as antiangiogenic agents was 2-fold. They decreased the angiogenic activity of the tumor cells, and they caused the endothelial cells to become refractory to inducers of angiogenesis. When tumor cells were treated in vitro with IFN-alpha A/D, there was a dramatic drop in their secretion of interleukin-8, the major angiogenic factor produced by these tumors. When combined with RA, which causes tumor cells to secrete an inhibitor of angiogenesis, there was a synergistic inhibition of both tumor cell growth and secreted angiogenic activity. The combination of RA and IFN-alpha also acted synergistically on endothelial cells by reducing their responsiveness to both interleukin-8 and tumor conditioned media. Doses of each drug could be reduced by two logs without loss of activity. When animals bearing human HNSCC tumor cells were treated systemically with a combination of RA and IFN-alpha A/D at doses that were ineffective when used alone, dramatic decreases in both tumor growth and tumor angiogenesis were seen. These data suggest that the use of antiangiogenic mixtures may be a particularly effective way to design future chemoprevention protocols against HNSCC.