Hearing conservation in surgery for glomus jugulare tumors

The most common ground on which surgery for glomus jugulare (GJ) tumors is criticized is the perceived risk of functional incapacity that attends possible cranial nerve (CN) loss. It is aggregate lower CN loss that is most often highlighted as particularly disabling to the quality of postsurgical survival. The documented success of both conservation surgery and operative rehabilitation of phonopharyngeal surgical deficits has, however, neutralized much of this criticism. The issue of hearing conservation (HC) in neurotologic skull base surgery, on the other hand, has not been well documented toward this end. The presence of a GJ neoplasm need not reflexly nor technically forfeit preexisting hearing. HC is, admittedly, a subordinate priority to total tumor removal, successful distal control of the internal carotid artery, and even facial nerve integrity. Yet, in appropriately selected patients, existing operative technology permits hearing preservation, a noteworthy addition to the high-grade functional outcome we have come to reasonably expect of conservation surgery. Hearing salvage further serves to define the concept of neurotologic skull base surgery. Hearing preservation in 122 GJ tumor patients is reviewed. Intuitively, as for acoustic tumor, HC appears tumor size related. Selection criteria for conservation surgery and its operative technique are detailed. Outcome is appropriately scored. The radiation therapy literature on this subject will be assiduously scrutinized for comparison.

On-line Raman spectroscopy of ribonucleotides preconcentrated by capillary isotachophoresis

Normal Raman spectroscopy is used as an on-line detector for capillary isotachophoresis (ITP) of adenosine 5'-triphosphate, adenosine 5'-diphosphate, and adenosine 5'-monophosphate in phosphate buffers. Preconcentration is from a 1 x 10(-2) M phosphate buffer (pH 7.5) into a leading electrolyte of 0.1 M KCl or Na2SO4, with a terminating electrolyte of 0.1 M 4-morpholinepropane-sulfonic acid. The ribonucleotides are concentrated to above 10(-2) M at the detection window, allowing measurement of Raman spectra with 1 s integration, from starting concentrations of 5 x 10(-6) M or higher.

Sequence and structural determinants of the interaction between the 5'-noncoding region of picornavirus RNA and rhinovirus protease 3C

It has previously been established that human rhinovirus 14 protease 3C binds specifically to the 5'-noncoding region of the viral RNA. A series of mutants of protease 3C and deletion or point mutants of the 5'-noncoding region of the viral RNA were analyzed to elucidate the sites of interaction between the protease and the RNA. Amino acids in protease 3C essential for RNA binding were found to be discontinuous in the amino acid sequence, and mutations which destroyed RNA binding did not affect the catalytic (proteolytic) activity of protease 3C. Based on the three-dimensional structure of rhinovirus 14 protease 3C, the RNA binding region is located in an extended area distinct from the catalytic triad. A single stem-loop structure of 27 nucleotides (stem-loop d) in the 5'-noncoding region was necessary and sufficient to bind protease 3C. Mutagenesis of either the base-paired stem or unpaired loop or bulge regions of stem-loop d suggested that the base-paired stem, but not the loop or bulge, carries important determinants of protease 3C binding. This conclusion is strengthened by the observation that rhinovirus 14 protease 3C bound specifically to the 5'-noncoding region of poliovirus RNA, and only the base-paired stem of stem-loop d is conserved between poliovirus and rhinovirus RNAs.

The human papillomavirus type 16 E2 transcription factor binds with low cooperativity to two flanking sites and represses the E6 promoter through displacement of Sp1 and TFIID

The E6 promoters of all genital human papillomaviruses have a characteristic alignment of transcription factor binding sites. Activation of the basic transcription complex at the TATA box depends upon a sequence-aberrant Sp1 site. Repression of E6 promoters is achieved by two binding sites for the viral E2 protein positioned between the Sp1 site and the TATA box. We have purified the human papillomavirus type 16 E2 protein after expression in Escherichia coli and studied its binding and repression properties with oligonucleotides representing the homologous promoter sequences. A Kd value of 3 x 10(-10) M indicated binding properties expected for a native protein. We found low cooperativity in the binding of two E2 dimers to flanking sites, both when these sites were separated by 3 nucleotides, as in the natural promoter, and when they were further apart. E2 protein, bound close to the distal Sp1 site, displaced the Sp1 factor even when the aberrant sequence was replaced by a typical Sp1 core recognition site. The high affinity of E2 protein for its binding site even led to Sp1 displacement at concentrations of E2 protein nearly 2 orders of magnitude lower than those of Sp1. Functional analyses of mutated E6 promoter sequences showed repression by this distal E2 binding site in the complete absence of binding to the proximal E2 binding site. From our findings and observations published by others, we conclude that each of the E2 binding sites in the E6 promoter of genital human papillomaviruses plays a separate role by displacing the transcription factors Sp1 and TFIID.

Efficient and rapid affinity purification of proteins using recombinant fusion proteases

In the affinity purification of recombinant fusion proteins, the rate-limiting step is usually the efficient proteolytic cleavage and removal of the affinity tail and the protease from the purified recombinant protein. We have developed a rapid, convenient and efficient method of affinity purification which can overcome this limitation. In one example of the method, the protease 3C from a picornavirus (3Cpro), which cleaves specific sequences containing a minimum of 6-7 amino acids, has been expressed as a fusion with glutathione S-transferase. The resultant recombinant 'fusion protease' cleaves fusion proteins bearing (from the amino-terminus) the same affinity tail as the fusion protease, a 3Cpro cleavage recognition site, and the recombinant protein of interest. The recombinant protein is purified in a single chromatographic step which removes both the affinity tail and the fusion protease. The advantages over existing methods include much improved specificity of proteolytic cleavage, complete removal of the protease and the affinity tail in one step, and the option of adding any desired amount of fusion protease to ensure efficient cleavage. The potential flexibility of the method is shown by the use of various affinity tails and alternative fusion proteases.

Human rhinovirus-14 protease 3C (3Cpro) binds specifically to the 5'-noncoding region of the viral RNA. Evidence that 3Cpro has different domains for the RNA binding and proteolytic activities

Protease 3C (3Cpro) encoded by human rhinovirus type 14 was purified from recombinant Escherichia coli and shown to bind specifically to the 5'-terminal 126 nucleotides of the viral RNA (126 RNA) in addition to efficiently cleaving a synthetic peptide in trans. The binding of 3Cpro to the viral RNA may be required for the initiation of plus strand viral RNA synthesis, suggesting a second non-proteolytic function for 3Cpro. Single amino acid substitutions were generated in 3Cpro at residues that are highly conserved among picornaviruses or that lie within the putative catalytic triad. Conservative changes at Asp-85 (D85E and D85N) destroyed the ability of 3Cpro to bind specifically to the 126 RNA, whereas the D85N mutation resulted in almost wild-type levels of proteolytic activity. Conversely, substitutions at His-40, Glu-71, or Cys-146 (H40D, E71A, or C146S) gave proteolytically inactive mutants that bound to the 126 RNA. These results suggest that the highly conserved Asp-85 is essential for specific binding to the 126 RNA, but is unlikely to function in proteolysis as the acidic member of the catalytic triad. Moreover, 3Cpro appears to have different domains for the RNA binding and proteolytic activities.

Characterisation of yeast phosphoglycerate kinase modified by mutagenesis at residue 21

Site-directed mutagenesis has been used to produce mutant forms of yeast phosphoglycerate kinase in which the conserved active-site residue, Arg21, has been replaced by a methionine or a lysine. Kinetic results obtained using these mutant enzymes show that their Km for both 3-phospho-D-glycerate and ATP are significantly different from those recorded for the wild-type enzyme. The Vmax for the lysine mutant is reduced by a factor of two from that of the wild-type enzyme whereas the Vmax for the methionine mutant is reduced more than sevenfold. A very clean electron-density-difference map shows little, if any, evidence of a structural change associated with the C-terminal domain, although resonances in the NMR spectra associated with the ATP-binding site (C-terminal domain) are also affected by the mutation as one might expect from the kinetic results. The NMR data show that binding at both the 3-phospho-D-glycerate and the non-productive ATP-binding site (associated with the N-terminal domain) are affected in the mutant in a way which is different to that associated with the wild-type enzyme. These results, taken together with the X-ray and kinetic data, indicate that the non-productive ATP-binding site and the activating anion-binding site are both associated with the basic patch region of yeast phosphoglycerate kinase.

The Levels of Emotional Awareness Scale: a cognitive-developmental measure of emotion

The Levels of Emotional Awareness Scale (LEAS) is based on a new cognitive-developmental model of emotional experience. The scale poses evocative interpersonal situations and elicits descriptions of the emotional responses of self and others which are scored using specific structural criteria. Forty undergraduates (20 of each sex) were tested. Interrater reliability and intratest homogeneity of the LEAS were strong. The LEAS was significantly correlated with two measures of maturity: the Washington University Sentence Completion Test (SCT) of Ego Development, and the Parental Descriptions Scale-a cognitive-developmental measure of object representation. In addition, the LEAS correlated positively with openness to experience and emotional range but not with measures of specific emotions, repression or the number of words used in the LEAS responses. These findings suggest that it is the level of emotion, not the specific quality of emotion, that is tapped by the LEAS.

Site-directed mutagenesis of histidine 62 in the 'basic patch' region of yeast phosphoglycerate kinase

Site-directed mutagenesis has been used to produce a mutant form of yeast phosphoglycerate kinase (PGK) in which the 'basic patch' residue His 62 has been replaced by a glutamine residue. Using 1H-NMR spectroscopy, it was found that 3-phosphoglycerate (3-PG) binding to the mutant protein induces the same conformational effects as for wild-type PGK, although the affinity was reduced by 2- to 3-fold. Kinetic studies show both Km for 3-PG and Vmax to be increased by approximately 2-fold relative to the wild-type enzyme. These data are consistent with the suggestion that His 62 assists in the binding of the substrate to the enzyme.

A simple, automated functional assay for protein C

Protein C is an important anticoagulant in circulating blood. The balance between the procoagulant and anticoagulant pathways determines whether a patient is at risk for thrombosis or hemorrhage, and low levels of protein C may result in thrombotic disease. It is important for clinical coagulation laboratories to measure protein C. For this purpose, a simple functional assay is needed. This article describes an automated assay for functional protein C with activation by copperhead venom. The authors have automated this assay for a centrifugal analyzer (COBAS Bio) and have proved the specificity of the assay by comparing values obtained amidolytically with those obtained with a radioimmunoassay for protein C.

NMR analysis of site-specific mutants of yeast phosphoglycerate kinase. An investigation of the triose-binding site

Site-specific mutants of yeast phosphoglycerate kinase have been produced in order to investigate the roles of the 'basic-patch' residues, arginine 168 and histidine 170. The fully-conserved residue, arginine 168, has been replaced with a lysine (R168K) and a methionine (R168M) residue, while the non-conserved histidine 170 has been replaced with an aspartate (H170D). Comparison of the 500-MHz 1H-NMR spectra of the mutant proteins with that of wild-type phosphoglycerate kinase shows that the overall fold of the mutants remains essentially unaltered from that of the native enzyme. Results of NOE experiments indicate that there are only very minor changes in structure in the vicinity of the mutations. These mutations have also led to firm sequence-specific resonance assignments to histidines 62, 167 and 170. NMR studies of 3-phosphoglycerate binding show that decreasing the positive charge in the sequence 168-170 reduces the binding of this substrate (by about 15-fold and 4-fold for mutants R168M and H170D respectively). Mutant R168K binds 3-phosphoglycerate with an affinity about twofold less than that of the native enzyme. Significantly, the activity of mutant H170D, measured at saturating substrate concentrations, is unchanged from that of the wild-type enzyme. This indicates that this residue is not of major importance in the binding or reaction of 3-phosphoglycerate. The observation is in agreement with results obtained for the wild-type enzyme, which indicate that 3-phosphoglycerate interacts most strongly with histidine 62 and least strongly with histidine 170, as would be predicted from the X-ray crystal structure. Substitution of positively charged arginine 168 with neutral methionine (or positively charged lysine) does not cause a detectable change in the pKa values of the neighbouring histidine groups, in as much as they remain below 3. The results reported here indicate that the observed reduction in catalytic efficiency relates less to direct electrostatic effects than to the mutants' inability to undergo 3-phosphoglycerate-induced conformational changes.

Site-directed mutagenesis of yeast phosphoglycerate kinase. The 'basic-patch' residue arginine 168

There is evidence, some of it of questionable authenticity, which suggests that phosphoglycerate kinase takes up a more compact form following the binding of substrates. Using this evidence it has been assumed that a conformational rearrangement is required for phosphoryl transfer to occur and that this is brought about by moving the enzyme's two domains towards each other. In order to test this hypothesis we have modified, by site-directed mutagenesis, an arginine residue thought to be involved in stabilising the transition-state intermediate. Although some 1.3 nm away from the site of phosphoryl transfer, as seen in the crystallographically determined structure, the substitution of arginine 168 by lysine (R168K) more than halves the specific activity of the enzyme. Substituting the arginine with a methionine (R168M) reduces activity further, but not completely, thus proving that the charge associated with this residue is not essential for catalytic activity. Both mutations raise the Michaelis constants (Km) for ATP and glycerate 3-phosphate. The largest change is observed with the triose substrate and the methionine mutant, suggesting that the primary function of arginine 168 is to influence the environment of this substrate. The effect on activity of adding sulphate to R168K and R168M mutant enzyme has also been investigated. The sulphate activation effect at low substrate concentrations is reduced for the methionine substitution but almost abolished for the lysine substitution. The most reasonable explanation of all these findings is that, in the wild-type enzyme, the guanidinium group of arginine 168 forms a hydrogen bond with one of the triose substrate's C1 oxygens. This steric arrangement would not be possible in the 'open form' of this enzyme as observed in the crystal structure.

The fate of trace metals during the metamorphosis of chironomids (diptera, chironomidae)

The fate of the trace metals zinc, cadmium and copper during the metamorphosis of chironomids was studied under field and experimental conditions. Field observations demonstrated a significant decrease in the trace metal body burden of larvae and imagines of Stictochironomus histrio Fabricius. No such difference were noted between successive developmental stages of Chironomus anthracinus Zett. The exuviae of both species contained small amounts of trace metals. Experiments, in which larvae of S. histrio and C. riparius Meigen were individually exposed, showed that larvae of both species accumulated substantial amounts of zinc and cadmium. For these metals, a transfer to pupae and imagines occurred. However, pupae had a lower body burden than larvae, and imagines a lower body burden than the pupae. Copper was also accumulated in the larvae, but it was excreted almost completely before the pupal stage. Elimination pathways of the trace metals during metamorphosis and the ecotoxicological consequences of trace metal transfer are discussed.

Ethanol-induced acute gastric injury in mast cell-deficient and congenic normal mice. Evidence that mast cells can augment the area of damage

The authors used stereomicroscopy and planimetry to measure the area of glandular stomach mucosa acutely injured by oral ethanol in mast cell-deficient and congenic normal (+/+) mice, and examined the damaged areas in 1-mu sections. Ethanol caused degranulation and/or disruption of gastric mucosal mast cells, and, at certain concentrations of ethanol, mast cell-deficient WBB6F1-W/Wv or WCB6F1-Sl/Sld mice developed significantly less (43-90% less) acute gastric injury than either congenic +/+ mice or WBB6F1-W/Wv mice whose mast cells were restored by bone marrow transplantation from WBB6F1-+/+ mice. Nevertheless, ethanol produced detectable, and in some cases substantial, gastric injury even in the complete absence of mast cells. Thus, ethanol can produce some damage to the gastric mucosa independently of mast cells. But these data suggest that under certain circumstances mast cells can augment the area of acute gastric injury induced by ethanol.

Synthesis and properties of oligonucleotides containing 2'-deoxynebularine and 2'-deoxyxanthosine

The preparation of synthetic oligonucleotides containing 2'-deoxynebularine (dN) and 2'-deoxyxanthosine (dX) is described. The thermal stabilities of duplexes containing dX, dN, and 2'-deoxyinosine (dI) base-paired with the four natural bases have been measured. Xanthine base pairs have stabilities at pH 5.5 that are similar to those of dI-containing duplexes at neutral pH. When xanthine is paired with adenine or cytosine an unusual stabilization of the duplex structure is observed at acid pH. Incorporation of base mispairs opposite template xanthine sites were measured using Drosophila DNA polymerase alpha. The relative nucleoside incorporation rates are in the order: T greater than C much greater than A approximately equal to G. These rates do not correlate with relative thermodynamic stabilities of base mispairs with xanthine obtained from Tm measurements: T greater than G greater than A approximately equal to C. We suggest that DNA polymerase misinsertion rates are greatest when the base mispair can be formed in accordance with Watson-Crick as opposed to other base pairing geometries even though other geometries, e.g. wobble, may result in a more stable final DNA product.

Land Use in Australia's Rangelands

Arguments for or against the re-allocation of land in Australia's rangelands from one use to another are frequently short on data and long on emotion. Although data presented in this paper are not sufficient to resolve these arguments, they do suggest some options for closer examination.Starting from a model for calculating viability prospects for pastoralism in the rangelands, the paper examines the extent of grazing and the pastoral viability prospects for the areas devoted to each of the major land uses. Possibilities for changes in use in each of the states are also described.

Estimating proximate populations for an extensive set of locations in Australia

"The paper reports the use of Australian Resources Information System to calculate two proximate populations (people living within (i) 150 and (ii) 500 km) for the centroids of each of 3,000 half by half degree geodetic grid cells covering Australia. The use of proximate population data is exemplified by computing a map of the eighteen regions collectively containing a maximum fraction of the Australian population." The data used are from the 1981 census.

Effect of amplification on the intelligibility of speech produced with an electrolarynx

The purpose of this study was to look at the effect of orolabial amplification on the intelligibility of speech spoken with a neck model electrolarynx for two distance conditions, three noise conditions, and in relative quiet. A speaker using a neck model electrolarynx read single-answer questions to six listeners. The questions were read with and without amplification at 1.5 and 2.5 m distance, in relative quiet as well as in 66 dB, 72 dB, and 76 dBSPL (A-weighted) prerecorded cafeteria noise. The results of the study showed that speech-to-noise ratios were improved for amplified speech, with improvement in intelligibility for speech spoken in moderate background noise (66 and 72 dBSPL). The effect of the "buzz" of the artificial larynx is reduced, and speakers are better understood in moderate background noise with this amplification system.

Physical, metabolic, and hormonal effects on men of long-term therapy with medroxyprogesterone acetate

Twenty-three men were treated with injectable medroxyprogesterone acetate (MPA) for sex-offending behavior. The physical, hormonal, and metabolic effects were monitored. The patients had significant (P less than 0.001) weight gain and increases (P less than 0.0001) in systolic blood pressure independent of weight gain. MPA therapy decreased testosterone (P less than 0.0001), luteinizing hormone (P less than 0.005), and testicular size (P less than 0.001), but not follicle-stimulating hormone. MPA's suppression of total sperm count was not consistent, but MPA significantly reduced sperm motility (P less than 0.001) and percent normal morphology (P less than 0.005). Statistically insignificant increases in insulin response without changes in glucose tolerance occurred in all patients, but only one patient developed overt diabetes mellitus. Three men developed gallstones, but none had significant changes in liver function. Patients receiving high-dose MPA therapy should be carefully monitored for blood pressure changes, diabetes mellitus, and gallbladder dysfunction.

The relation between technical variation and the mean in the mixed lymphocyte reaction in the rat

Technical variation is a linear function of the incremental mean in the mixed lymphocyte reaction (MLR) and is independent of the immune status of the responders and the gene dose of the stimulators. Logarithmic transformation of the absolute count/control mean makes technical variation independent of the mean. We recommend that this transformation be used before parametric analysis of the data.

The effect of sex steroids on radioimmunoassayable plasma somatomedin C concentrations

While the effect of sex steroids on growth is well known, their effects on somatomedin C, a mediator of growth, are unclear. To investigate the effect of sex steroids on somatomedin C (Sm-C) concentrations, Sm-C was measured in adults receiving pharmacological doses of various sex steroids (estrogens, testosterone, and medroxyprogesterone acetate). Testosterone therapy had no effect on the somatomedin C concentration. Although both estrogen and medroxyprogesterone acetate therapy reduced the plasma testosterone concentration into the normal female range, they had different effects on Sm-C concentrations. Estrogen therapy produced no detectable change in the Sm-C concentration; medroxyprogesterone acetate caused an increase in the plasma somatomedin C concentration (P less than 0.001). Since medroxyprogesterone acetate also does not increase the serum GH concentration, other mechanisms by which medroxyprogesterone acetate stimulates Sm-C production are discussed.

An alternate method for synthesis of double-stranded DNA segments

Recent progress in the chemical synthesis of DNA has now made it possible to rapidly synthesize single-stranded DNAs over 40 bases in length. We have taken advantage of these longer DNAs in assembling and cloning a 132-base pair gene segment coding for amino acids 126 through the stop codon of human leukocyte interferon alpha 2. The method used involves DNA polymerase I-mediated repair synthesis of synthetic oligonucleotide substrates having short stretches of complementary sequence at their 3' termini. In the presence of DNA polymerase I and the four deoxyribonucleoside triphosphates, those primer-templates are converted to full length double-stranded DNAs. The economy in chemical synthesis using this approach is substantial with a greater than 40% reduction in the amount of chemical synthesis required as compared with the conventional approach. We describe in detail this methodology for the biochemical assembly of long gene segments from synthetic oligodeoxyribonucleotides.