Thiazolo[4,5-d]pyrimidine nucleosides. The synthesis of certain 3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidines as potential immunotherapeutic agents

Novel analogues of the naturally occurring purine nucleosides were synthesized in the thiazolo[4,5-d]pyrimidine ring system to determine the immunomodulatory effects of insertion of a sulfur atom in place of nitrogen at position 7 of the purine ring. In particular, 5-amino-3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidine-2,7(3H,6H) -dione (7, guanosine analogue), 3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidine-2,5,7(3H,4H,6H) trione (8, xanthosine analogue), 3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidine-2,7(3H,6H)-dione (10, inosine analogue), and 7-amino-3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidin-2(3H)-one (32, adenosine analogue) were prepared, as well as the 8-mercaptoguanosine (14) and 6-mercaptoguanosine (17) analogues. Single-crystal X-ray studies confirmed the structural assignment of 17 and 32 as having the beta-configuration with the site of glycosylation at N3. The nucleosides were evaluated for their ability to potentiate various murine immune functions in direct comparison to the known active agents 8-bromoguanosine (1), 8-mercaptoguanosine (2), and 7-methyl-8-oxoguanosine (3). Two of the guanosine analogues, 7 and 14, were found to exhibit significant immunoactivity relative to the positive control compounds (1-3), while the adenosine, inosine, xanthosine, and 6-mercaptoguanosine analogues were devoid of activity. Compound 7 exhibited greater immunoactivity than any of the other guanosine analogues and derivatives in all test systems. Specifically, 7 was shown to be about twice as potent as 3 in the murine spleen cell mitogenicity assay. In addition, treatment with 7 produced about a 4-fold increase in natural killer cell cytotoxicity, while treatment with 3 afforded a 3-fold increase over controls. Finally, 7 provided excellent protection (92% survivors compared to 0% for placebo controls) against Semliki Forest virus in mice. Induction of interferon may account for the major mode of action of these guanosine analogues.

Implants in the treatment of the maxillofacial patient

Despite the apparent advantages provided by implants to the maxillofacial patient, complete documentation of these benefits is lacking in the literature. This review uses existing published material as a basis to discuss the efficacy of implant use in maxillofacial prosthetics and the biologic rationale of the procedures. The use of implants with bone-anchored hearing aids; in maxillofacial surgery; and in maxillary, mandibular, and facial defects is presented. Reliable and valid patient-based evidence of treatment success, as suggested by the NIH Consensus Conference of 1988, is needed.

Voyager Radio Science Observations of Neptune and Triton

The Voyager 2 encounter with the Neptune system included radio science investigations of the masses and densities of Neptune and Triton, the low-order gravitational harmonics of Neptune, the vertical structures of the atmospheres and ionospheres of Neptune and Triton, the composition of the atmosphere of Neptune, and characteristics of ring material. Demanding experimental requirements were met successfully, and study of the large store of collected data has begun. The initial search of the data revealed no detectable effects of ring material with optical depth tau [unknown] 0.01. Preliminary representative results include the following: 1.0243 x 10(26) and 2.141 x 10(22) kilograms for the masses of Neptune and Triton; 1640 and 2054 kilograms per cubic meter for their respective densities; 1355 +/- 7 kilometers, provisionally, for the radius of Triton; and J(2) = 3411 +/- 10(x 10(-6)) and J(4) = -26(+12)(-20)(x10(-6)) for Neptune's gravity field (J>(2) and J(4) are harmonic coefficients of the gravity field). The equatorial and polar radii of Neptune are 24,764 +/- 20 and 24,340 +/- 30 kllometers, respectively, at the 10(5)-pascal (1 bar) pressure level. Neptune's atmosphere was probed to a pressure level of about 5 x 10(5) pascals, and effects of a methane cloud region and probable ammonia absorption below the cloud are evident in the data. Results for the mixing ratios of helium and ammonia are still being investigated; the methane abundance below the clouds is at least 1 percent by volume. Derived temperature-pressure profiles to 1.2 x 10(5) pascals and 78 kelvins (K) show a lapse rate corresponding to "frozen" equilibrium of the para- and ortho-hydrogen states. Neptune's ionosphere exhibits an extended topside at a temperature of 950 +/- 160 K if H(+) is the dominant ion, and narrow ionization layers of the type previously seen at the other three giant planets. Triton has a dense ionosphere with a peak electron concentration of 46 x 10(9) per cubic meter at an altitude of 340 kilometers measured during occultation egress. Its topside plasma temperature is about 80 +/- 16 K if N(2)(+) is the principal ion. The tenuous neutral atmosphere of Triton produced distinct signatures in the occultation data; however, the accuracy of the measurements is limited by uncertainties in the frequency of the spacecraft reference oscillator. Preliminary values for the surface pressure of 1.6 +/- 0.3 pascals and an equivalent isothermal temperature of 48 +/- 5 K are suggested, on the assumption that molecular nitrogen dominates the atmosphere. The radio data may be showing the effects of a thermal inversion near the surface; this and other evidence imply that the Triton atmosphere is controlled by vapor-pressure equilibrium with surface ices, at a temperature of 38 K and a methane mixing ratio of about 10(-4).

The immediate role of the dentist in the maxillectomy patient

It is imperative that comprehensive planning takes place for the potential maxillectomy patient. Input from the dentist is required for all stages of the procedure, from initial consultation to placement of the final prosthesis. By utilizing an interim dental prosthesis (splint), the impact of tissue loss, wound fibrosis and neurological damage can be minimized. In this paper, the authors address the initial stage in the treatment sequence, the surgical splint.

Prostatic carcinoma presenting with neck metastasis

Prostatic carcinoma is the second leading cause of cancer mortality in American men. Twenty-seven thousand deaths from this aggressive neoplasm were predicted for 1987. Although this malignancy has metastasized to almost all of the structures in the head and neck, it demonstrates a pathophysiologic proclivity for the supraclavicular lymph nodes. Combining fine-needle aspiration with immunohistochemical techniques produces a cost-effective method to expedite the diagnosis of this hormone-responsive tumor. Four patients presenting with prostatic carcinoma and neck metastasis in a three-year period are reported and discussed.

Assessment of the BACTEC NR660 blood culture system for the detection of bacteremia in young children

The sensitivity of the BACTEC NR660 blood culture system was assessed by using paired bottles of anaerobic (NR7A) and resin-containing aerobic (NR16A) media and conditions and organisms which simulated those found in pediatric practice. Corresponding media (7D and 16B) of the established BACTEC 460 radiometric method served as controls. The performances of the two systems were similar with 50 isolates of 10 aerobic organisms (aerobic medium) and with 21 isolates of 15 strict anaerobes (anaerobic medium).

Low dose combined chemotherapy/radiotherapy in the management of locally advanced urethral squamous cell carcinoma

The successful treatment of a patient with bulky squamous cell carcinoma of the urethra using low dose preoperative radiation therapy and concurrent chemotherapy is described. Dramatic rapid tumor response facilitated surgical resection of the remaining microscopic disease. This clinical behavior is remarkably similar to that seen with squamous cell carcinoma of the anal canal and esophagus when a similar regimen is used. At the latter tumor sites the successful use of combination radiotherapy and chemotherapy has reduced the morbidity of subsequent surgery, and in selected cases has obviated the need for a radical operation. Further investigation of such combination treatment is warranted for urethral carcinoma.

Ethylene biosynthesis-inducing protein from cellulysin is an endoxylanase

The proteinaceous ethylene biosynthesis-inducing factor (EIF) that was purified from Cellulysin was also shown to contain a xylanase activity. In all nondenaturing protein separation methods employed (Sephacryl S-200 chromatography, and preparative isoelectric focusing and agarose electrophoresis), xylanase activity copurified with the ethylene biosynthesis-inducing activity. Treatment with heat (60 degrees C) or proteases in 8 molar urea inhibited both ethylene-inducing and xylanase activities. Antibodies raised against purified EIF, which contains three polypeptides of 18, 14, and 10 kilodaltons, immunoprecipitated both ethylene biosynthesis-inducing and xylanase activities. The purified EIF contained no detectable cellulase, polygalacturonase, or protease activity. Other hydrolytic activities as estimated by using p-nitrophenyl derivatives of several sugars as substrates also were not detected. Different commercially available hydrolytic enzyme preparations were tested for both ethylene biosynthesis-inducing and xylanase activities. All enzymes tested contained xylanase activity, but only a few induced ethylene biosynthesis. Western blots of proteins separated by SDS-PAGE, using antibodies prepared against the non-denatured purified EIF, revealed two major bands of about 18 and 14 kilodaltons in EIF. These antibodies seem to be specific for these proteins from Trichoderma viride, because there was little cross-reactivity with the other proteins in Cellulysin and other commercial enzyme preparations. Based on these data, we suggest that EIF contains a specific xylanase activity which is involved in inducing ethylene biosynthesis.

Ocular trauma

Well over half a million people in the world are blind as a result of eye injuries. It is not known how much of the final visual damage is the result of delayed or inappropriate management at the primary care level. However, it is certain that the outcome of ocular trauma by prompt action that will prevent serious loss of sight. He or she requires neither specialist knowledge, nor expensive instruments, but only the common sense application of a few basic clinical skills.

Animal evaluation of a new pericardial bioprosthetic heart valve

Implantation in animals is an essential step in the evaluation of any new prosthetic heart valve before commencing clinical trials. A new three-leaflet pericardial bioprosthesis developed in Glasgow has been implanted in the mitral position in ten sheep and eight dogs. Eleven animals were electively killed after 3 months of observation and explanted valves were in good condition. Hydrodynamic tests of the explanted valves showed small changes in function compared to tests prior to implantation. This was mainly due to host tissue ingrowth over the edge of the leaflets. Histological studies confirmed good preservation of the pericardial tissue in explanted valves.

The in-vitro assessment of a collagen/vicryl (polyglactin) composite film together with candidate suture materials for use in urinary tract surgery. II. Surface deposition of urinary salts

Collagen coated vicryl mesh has been incubated with a series of urine collections from healthy and stone-forming patients. For comparison, collagen film, vicryl mesh, and a number of absorbable and non-absorbable sutures were similarly tested. Incubation in rabbit urine were also included in the study. Deposition of urinary salts, estimated qualitatively by electron microscopy, were observed on the collagen vicryl composite in approximately two thirds of the urines tested including rabbit urine. Those urines from patients with a high calcium excretion in particular caused urinary deposits on the material. Similar results were obtained with collagen film although the latter was not tested in rabbit urine. Considerably less deposits of urinary constituents were found with other absorbable materials such as vicryl mesh, vicryl sutures, and chromic catgut, whereas a higher proportion of concretions were found with the non-absorbable sutures. The results indicate that urinary salt deposition may be a problem associated with collagen based composite materials after prolonged exposure to urine. It must, however, be emphasised that great care should be exercised when extrapolating any results obtained in-vitro to the in-vivo situation.

SIGNAL blood culture system for detection of bacteremia in neonates

In the SIGNAL (Oxoid Ltd., Basingstoke, United Kingdom) blood culture system, gas produced by bacterial metabolism displaces medium from the culture bottle into an upper reservoir via a hollow needle. Displacement of media may provide a visual indication of the presence of both aerobic and anaerobic organisms in a single medium. The single-bottle SIGNAL system was compared with paired BACTEC 16B and 7D (Johnston Laboratories, Inc., Towson, Md.) radiometric system bottles by using bacterial inocula and conditions which simulated those found in neonatal and pediatric populations. The single SIGNAL bottle was a good as the combined BACTEC media for Escherichia coli and Staphylococcus aureus, but was slower for Candida spp., Haemophilus influenzae, Pseudomonas aeruginosa, Staphylococcus epidermidis, group B streptococci, alpha-streptococci, and pneumococci. The SIGNAL system failed to detect four of five isolates of Neisseria meningitidis and four of eight anaerobic organisms. The SIGNAL system is not suitable for neonatal blood cultures at its present state of development.