Cloning of the 18S rDNA gene, an internal transcribed spacer, and the 5' region of the 28S rDNA gene of Cope's gray treefrog, Hyla chrysoscelis

The location of rDNA genes on the chromosomes of most species is identical within that species, usually occurring on the same chromosome or chromosomes. This is not the case in Cope's gray treefrog, Hyla chrysoscelis, where the rDNA genes are polymorphic for chromosome location. The occasions leading to this polymorphism have yet to be determined. The first step in understanding the nature of the polymorphism is the characterization of the ribosomal gene array. Here we describe the cloning, sequencing, and confirmation, by fluorescence in situ hybridization, of the 18S rDNA gene, a region which includes the end of the 18S rDNA gene, an internal transcribed spacer, and a portion of the 5' end of the 28S rDNA gene in H. chrysoscelis.

The redox-sensitive transcriptional activator OxyR regulates the peroxide response regulon in the obligate anaerobe Bacteroides fragilis

The peroxide response-inducible genes ahpCF, dps, and katB in the obligate anaerobe Bacteroides fragilis are controlled by the redox-sensitive transcriptional activator OxyR. This is the first functional oxidative stress regulator identified and characterized in anaerobic bacteria. oxyR and dps were found to be divergently transcribed, with an overlap in their respective promoter regulatory regions. B. fragilis OxyR and Dps proteins showed high identity to homologues from a closely related anaerobe, Porphyromonas gingivalis. Northern blot analysis revealed that oxyR was expressed as a monocistronic 1-kb mRNA and that dps mRNA was approximately 500 bases in length. dps mRNA was induced over 500-fold by oxidative stress in the parent strain and was constitutively induced in the peroxide-resistant mutant IB263. The constitutive peroxide response in strain IB263 was shown to have resulted from a missense mutation at codon 202 (GAT to GGT) of the oxyR gene [oxyR(Con)] with a predicted D202G substitution in the OxyR protein. Transcriptional fusion analysis revealed that deletion of oxyR abolished the induction of ahpC and katB following treatment with hydrogen peroxide or oxygen exposure. However, dps expression was induced approximately fourfold by oxygen exposure in DeltaoxyR strains but not by hydrogen peroxide. This indicates that dps expression is also under the control of an oxygen-dependent OxyR-independent mechanism. Complementation of DeltaoxyR mutant strains with wild-type oxyR and oxyR(Con) restored the inducible peroxide response and the constitutive response of the ahpCF, katB, and dps genes, respectively. However, overexpression of OxyR abolished the catalase activity but not katB expression, suggesting that higher levels of intracellular OxyR may be involved in other physiological processes. Analysis of oxyR expression in the parents and in DeltaoxyR and overexpressing oxyR strains by Northern blotting and oxyR'::xylB fusions revealed that B. fragilis OxyR does not control its own expression.

A comparative study of the clinical efficacy of nedocromil sodium and placebo. How does cromolyn sodium compare as an active control treatment?

Nedocromil sodium and cromolyn sodium are the only two currently available nonsteroid anti-inflammatory agents for treatment of asthma. Clinical differences between the two agents remain under continuous investigation with reports differentiating the two on the basis of atopy of the patient and reversibility of bronchoconstriction. This study investigated the efficacy of nedocromil sodium (4 mg, qid) for treatment of mild-to-moderate asthma in comparison to placebo using cromolyn sodium (2 mg, qid) as an active control treatment. Patients were primarily allergic asthmatics (with at least 15% reversibility) previously maintained on a regimen of regular bronchodilator therapy. During a 2-week run-in period, the patient's slow-release theophylline therapy was removed, and the patients were randomized to treatment after deterioration of asthma control (asthma symptom summary score of 3 for 7 of the 14 days). After 8 weeks of treatment, patients were returned to as occasion requires bronchodilator therapy, as per the 2-week baseline period. The results demonstrate that patients treated with nedocromil sodium showed statistically significant improvements during the primary time period (mean weeks 3 through 8) over placebo-treated patients as evidenced by all indexes of asthma symptoms, pulmonary function measures, and decreased bronchodilator reliance (p<0.05). Patients treated with cromolyn sodium demonstrated similar improvements over placebo-treated patients. Comparisons between nedocromil sodium and cromolyn sodium showed the two agents to be comparable in this group of primarily allergic patients with reversible disease. Between-group differences were noted for 3 of the 13 variables (nighttime asthma, FEV1, and forced expiratory flow rate between 25 % and 75% of the FVC) in favor of cromolyn sodium when the data were pooled during the primary time period. The number of patients missing 1 or more days from work/school/regular activity due to asthma was significantly fewer compared with placebo, and favoring nedocromil sodium over cromolyn sodium. No differences were observed among the three treatments for adverse events. This study demonstrated that in primarily allergic patients with reversible airways disease, nedocromil sodium and cromolyn sodium are both significantly more effective than placebo for treatment of mild-to-moderate asthma.

14N Nuclear Magnetic Resonance Relaxation of the Nitrate Ion and Ion Pairing in Aqueous Solution

14 N n.m.r. spin-lattice relaxation times of four metal nitrate salts were measured as a function of concentration in aqueous solution. The concentration dependence of T1 was attributed to the formation of ion pairs with increasing concentration in these solutions. The T1 data, allowing for viscosity corrections, were treated by a two-state model of 'free' and 'bound' nitrate ions and to both possibilities of slow and fast exchange between the two states. In the equilibrium expressions estimates of the relevant activity coefficients were included. The slow nitrate exchange mechanism was favoured and the values obtained for this particular mechanism compared well with those derived from alternative measurements.

Nitrate Selectivity of Ion-Exchange Resins and of Their Model Compounds. II. Viscosity and Density of Benzyltrialkylammonium Salts in Aqueous Solution and 14N N.M.R. Relaxation of the Nitrate Ion

The densities and viscosities of benzyltrialkylammonium chlorides and nitrates were determined in aqueous solution; the alkyl substituents were methyl, ethyl, propyl , butyl and pentyl . The concentration dependence of the 14N nuclear spin relaxation of the nitrate ion was used to find ion pair association constants for comparison with those derived from conductivity measurements (Part I). Density measurements were used to determine partial molar volumes, and viscosity measurements to find hydrodynamic volumes of the solutes. With the assumption of additivity of ionic volumes, cationic volumes calculated from the two series of chloride and nitrate salts agreed well. The increase in the ratio of hydrodynamic to partial ionic volumes with increasing chain length of the alkyl substituent was interpreted as a corresponding increase in hydrophobic hydration.

Varicella-zoster virus (VZV) transcription during latency in human ganglia: construction of a cDNA library from latently infected human trigeminal ganglia and detection of a VZV transcript

The entire varicella-zoster virus (VZV) genome appears to be present in latently infected human ganglia, but the extent of virus DNA transcription is unknown. Conventional methods to study virus gene transcripts by Northern (RNA) blotting are not feasible, since ganglia are small and VZV DNA is not abundant. To circumvent this problem, we prepared radiolabeled cDNA from ganglionic RNA, hybridized it to Southern blots containing VZV DNA, and demonstrated the presence of a transcript within the SalI C fragment of the virus genome (R. Cohrs, R. Mahalingam, A. N. Dueland, W. Wolf, M. Wellish, and D. H. Gilden, J. Infect. Dis. 166:S24-S29, 1992). To further map VZV transcripts, in the work described here we constructed a cDNA library from poly(A)+ RNA obtained from latently infected human ganglia. Phage DNA isolated from the library was used in PCR amplifications to detect VZV-specific inserts. The specificity of the PCRs was provided by selection of a primer specific for VZV gene 17, 18, 19, 20, or 21 and a second vector-specific primer. VZV gene 21-specific sequences were identified by PCR amplification. The PCR product contained the XhoI cloning site and poly(A)+ sequences between vector and VZV gene 21 sequences. The sequence motif at the 3' end of VZV gene 21, determined by cloning and sequencing of the PCR product, consisted of 49 to 51 nucleotide bases of 3'-untranslated DNA, the termination codon for the VZV gene 21 open reading frame, and DNA sequences reading into the VZV gene 21 open reading frame.

Inhibition of IL-1 release from human monocytes and suppression of streptococcal cell wall and adjuvant-induced arthritis in rats by an extract of Tripterygium wilfordii Hook

1. It was investigated whether an extract of Tripterygium wilfordii Hook f (TW) inhibits IL-1 production by monocytes and suppresses the development of IL-1-dependent arthritis induced in rats with streptococcal cell wall and adjuvant. 2. TW preferentially inhibited IL-1 alpha and IL-1 beta production by bacterial lipopolysaccharide (LPS)-stimulated human monocytes with IC50 of approximately 1 microgram/ml. 3. Oral administration of TW dose-dependently suppressed joint swelling and structural damage in streptococcal cell wall-induced arthritis (ED50 = 20 mg/kg/day) and in adjuvant-induced arthritis (ED50 = 46 mg/kg/day for developing and 8 mg/kg/day for established arthritis).

The ETO portion of acute myeloid leukemia t(8;21) fusion transcript encodes a highly evolutionarily conserved, putative transcription factor

The 8;21 translocation, t(8;21)(q22;q22.3), is seen only in acute myelogenous leukemia and is characteristically associated with the M2 subtype. Subsequent to our identification of the t(8;21) breakpoint region on chromosome 21, we reported that the translocation results in the fusion of the AML1 gene on chromosome 21 with a novel gene on chromosome 8 which we called ETO (for eight twenty-one). Recently, the AML1 portion of the fusion protein has been shown to correspond to the DNA-binding and dimerization domains of the mouse gene, polyoma enhancer binding protein 2 alpha B (pebp 2 alpha B). We report here the complete sequence of the ETO portion of the fusion transcript as compiled from complementary DNAs from a t(8;21) AML patient and compare this with the ETO sequence from a mouse brain transcript. The deduced amino acid sequences are 99% identical. ETO has several features consistent with it being a transcription factor. The ETO sequence is different from the portion of PEBP 2 alpha B it replaces in the AML1/ETO fusion protein, except for their common high content of proline, serine, and threonine residues. Because neither the putative zinc fingers nor the TAF110 homology domain of ETO is present in PEBP2 alpha B, one might expect functional differences in the ability of AML1/ETO protein to affect the levels of transcription of genes normally regulated to some degree by AML1 (PEBP2 alpha B) during myeloid differentiation. The relatively high levels of ETO in developing brain suggest that it could be involved in the regulation of some aspect of neural proliferation or differentiation.

Patient simulation using seamless digital video

This manuscript describes a method for using digital-video technology to create patient simulations in which the simulated patient is always active on the computer screen. We outline the technical method we have developed, and we present the lessons learned in applying the method to develop a prototype patient simulation.

Isolated diffusing capacity reduction in systemic sclerosis

OBJECTIVE

To determine the long-term outcome of patients with systemic sclerosis (SSc) and an isolated reduction in the diffusing capacity for carbon monoxide (DLCO) at the time of initial evaluation.

METHODS

Patients with an isolated reduction in DLCO (i.e., normal forced vital capacity [FVC] and normal ratio of the forced expiratory volume in one second [FEV1] to the FVC) on initial evaluation were identified from among 815 patients with SSc who were carefully followed up throughout their illness. We requested that patients have repeat pulmonary function testing (PFT), and the outcomes of these tests, as well as cardiopulmonary and survival outcomes, were determined.

RESULTS

An isolated reduction in DLCO, with a normal FVC was detected in 152 (19%) of the 815 patients. A subset of those with an isolated reduction in DLCO (11%) developed isolated pulmonary hypertension and had severely reduced survival rates. Pulmonary hypertension was strongly associated with an initial DLCO of less than 55% of predicted normal and a FVC (% predicted)/DLCO (% predicted) ratio of greater than 1.4. Among all patients in whom this ratio was greater than 1.4, 22% developed isolated pulmonary hypertension, compared with only 2% of those whose ratio was less than 1.4 (P less than 0.01). Of the 152 patients with isolated DLCO reduction, 73 (48%) underwent PFTs a mean of 5.4 years (range 2.0-13.2) after the initial PFT. Only 6 (8%) of these 73 patients ever had serious pulmonary disease: 5 had isolated pulmonary hypertension, and 1 had severe pulmonary fibrosis. Half of the patients with a low initial DLCO demonstrated a significant improvement (greater than 20%) at followup testing that could not be explained by the demographic, clinical, or laboratory findings at the first visit.

CONCLUSION

Isolated reduction in DLCO is a frequent abnormality in SSc. Overall, it is associated with a good prognosis for survival and for pulmonary morbidity. A small subset of patients (11%) who have a very low DLCO (less than 55% of predicted) have developed isolated pulmonary hypertension, all of whom had limited scleroderma.

Studies of the initiation of myelination by Schwann cells

The rapid morphologic changes in Schwann cells and in their relationships to axons during the transition from the premyelinating to the myelinating state have been known for more than 15 years. The sorting of axons by dividing Schwann cells, the establishment of a 1:1 relationship between a postmitotic Schwann cell, and the onset of myelin sheath formation have all been described in detail. However, the chain of molecular events and mechanisms by which these morphologic changes are regulated has not been elucidated. In this chapter we have reviewed results that strongly suggest that the adhesion molecule L1 is one of the important determinants that mediate the elongation of the Schwann cell along the axon, and the extension of Schwann processes to engulf axons. Thus, L1 functions to promote the spreading of the Schwann cell process over the surface of the axon. L1 does not appear to be exclusively involved in the adhesion of Schwann cells to axons, in the activation of Schwann cell proliferation by axons, or in the induction of synthesis of extracellular matrix proteins. The results from the anti-L1 blocking experiments further provided clues for an understanding of how the expression of GalC and MAG, which are both likely to be involved in the initiation of myelination, are regulated. These results imply that the overall regulation of expression of these early myelin components could require controls other than a single signaling mechanism derived from contact with axons. We propose that the deposition of basal lamina or one of its components could also be involved. Finally, the results from anti-GalC-blocking experiments indicated that GalC is involved in the mechanism of early growth of the myelin spiral.

Mechanisms of injury in unilateral testis torsion

We investigated the mechanisms of injury involved in unilateral testis torsion as well as the interventional effects of orchiectomy at 48 h and immunosuppression with corticosteroids in rats. Torsion was associated with abnormal contralateral testis histology and raised antilymphocytes and antisperm antibody titers. Both orchiectomy and steroid administration lessened these findings, suggesting that an immunological process underlies the abnormality seen in this experiment model.

Randomized comparisons of radiotherapy and nitrosoureas for the treatment of malignant glioma after surgery

Within three weeks of definitive surgical intervention, 467 patients with histologically proved malignant glioma were randomized to receive one of four treatment regimens: semustine (MeCCNU), radiotherapy, carmustine (BCNU) plus radiotherapy, or semustine plus radiotherapy. We analyzed the data for the total randomized population and for the 358 patients in whom the initial protocol specifications were met (the valid study group). Observed toxicity included acceptable skin reactions secondary to radiotherapy and reversible leukopenia and thrombocytopenia due to chemotherapy. Radiotherapy used alone or in combination with a nitrosourea significantly improved survival in comparison with semustine alone. The group receiving carmustine plus radiotherapy had the best survival, but the difference in survival between the groups receiving carmustine plus radiotherapy and semustine plus radiotherapy was not statistically significant. The combination of carmustine plus radiotherapy produced a modest benefit in long-term (18-month) survival as compared with radiotherapy alone, although the difference between survival curves was not significiant at the 0.05 level. This study suggests that it is best to use radiotherapy in the post-surgical treatment of malignant glioma and to continue the search for an effective chemotherapeutic regimen to use in addition to radiotherapy.

Pathologic flail chest complicating multiple myeloma

Pathologic flail chest complicated the initial presentation of multiple myeloma in two patients. Both had severe hypercalcemia and diffuse bone disease. Atelectasis and pulmonary edema preceded the appearance of flail chest in one patient; atelectasis complicated the flail chest in the second patient and increased the severity of the flail. Both were treated with radiotherapy and chemotherapy. However, delay in stabilizing the first patient's chest wall with positive airway pressure was followed by extension of the flail chest and irreversible respiratory failure. On the other hand, prolonged stabilization of the chest wall in the second patient until a chemotherapy-induced remission occurred was associated with resolution of the flail chest.

Evaluation of BCNU and/or radiotherapy in the treatment of anaplastic gliomas. A cooperative clinical trial

A controlled, prospective, randomized study evaluated the use of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and/or radiotherapy in the treatment of patients who were operated on and had histological confirmation of anaplastic glioma. A total of 303 patients were randomized into this study, of whom 222 (73%) were within the Valid Study Group (VSG), having met the protocol criteria of neuropathology, corticosteroid control, and therapeutic approach. Patients were divided into four random groups, and received BCNU (80 mg/sq m/day on 3 successive days every 6 to 8 weeks), and/or radiotherapy (5000 to 6000 rads to the whole brain through bilateral opposing ports), or best conventional care but no chemotherapy or radiotherapy. Analysis was performed on all patients who received any amount of therapy (VSG) and on the Adequately Treated Group (ATG), who had received 5000 or more rads radiotherapy, two or more courses of chemotherapy, and had a minimum survival of 8 or more weeks (the interval that would have been required to have received either the radiotherapy or chemotherapy). Median survival of patients in the VSG was, best conventional care: 14 weeks (ATG: 17.0 weeks); BCNU: 18.5 weeks (ATG: 25.0 weeks); radiotherapy: 35 weeks (ATG: 37.5 weeks); and BCNU plus radiotherapy: 34.5 weeks (ATG: 40.5 weeks). All therapeutic modalities showed some statistical superiority compared to best conventional care. There was no significant difference between the four groups in relation to age distribution, sex, location of tumor, diagnosis, tumor characteristics, signs or symptoms, or the amount of corticosteroid used. An analysis of prognostic factors indicates that the initial performance status (Karnofsky rating), age, the use of only a surgical biopsy, parietal location, the presence of seizures, or the involvement of cranial nerves II, III, IV, and VI are all of significance. Toxicity included acceptable, reversible thrombocytopenia and leukopenia.

Evaluation of mithramycin in the treatment of anaplastic gliomas

A controlled, prospective, randomized study evaluated the use of mithramycin in the treatment of anaplastic glioma compared to a similar group of patients receiving best conventional care. From a total of 116 patients in the study, 96 were within the valid study group. All patients were operated on, had histological confirmation of anaplastic glioma, and received radiotherapy at the discretion of the principal investigator. Fifty-two patients received mithramycin at a dose of 25 mug/kg/day for 21 days, while 44 patients were in the control group. There was no significant difference in the median survival from time of randomization in those receiving mithramycin (21 weeks) as compared to those not receiving mithramycin (26 weeks). There was no significant difference between the two groups in relation to age distribution, sex, location, diagnosis, tumor characteristics, signs or symptoms, or radiotherapy received. Duration of symptoms correlates positively with survival and was also significantly longer in the control group than in the treated group. This, however, did not account for the failure of mithramycin to be found an effective agent. Although the study was not designed to evaluate the efficacy of radiotherapy, patients who were so treated had a significant improvement in survival. The toxic complications of mithramycin included gastrointestinal symptoms, dermatological involvement, anemia, and liver dysfunction, indicating the need for close supervision.

[Intraocular and cerebral reticular sarcoma]

An anatomo-clinical study is presented of a reticulum cell sarcoma (or lymphosarcoma), limited to the eye-ball and the brain. The eye disease developed as a chronic, diffused hypertensive uveitis. The diagnosis of the nature of the brain tumour was made by cytological study of the cerebro-spinal fluid.

Myocardial perfusion and metabolism at normothermic and hypothermic levels

Changes in intramyocardial carbon dioxide tension (Pco2) and arterial oxygen tension (Po2) were recorded in dogs with a mass spectrometer after temporary occlusion of the aorta and the proximal part of the anterior descending coronary artery at normothermic and hypothermic levels. Patterns of hypoxic and hypercapnic changes and their recovery were favorably modified with moderate hypothermia. Deep levels of hypothermia seemed to enhance this protective effect and progressively slow the myocardial metabolism. Occlusion of the proximal part of the anterior descending coronary artery for 30 minutes had a regional effect similar to the general myocardial changes recorded after aortic clamping, while the posterior myocardial probe showed stable control values. These data support previous studies showing that moderate hypothermia halves the oxygen consumption and doubles the "safe" period of anoxic arrest.