An L40C mutation converts the cysteine-sulfenic acid redox center in enterococcal NADH peroxidase to a disulfide

Multiple sequence alignments including the enterococcal NADH peroxidase and NADH oxidase indicate that residues Ser38 and Cys42 align with the two cysteines of the redox-active disulfides found in glutathione reductase (GR), lipoamide dehydrogenase, mercuric reductase, and trypanothione reductase. In order to evaluate those structural determinants involved in the selection of the cysteine-sulfenic acid (Cys-SOH) redox centers found in the two peroxide reductases and the redox-active disulfides present in the GR class of disulfide reductases, NADH peroxidase residues Ser38, Phe39, Leu40, and Ser41 have been individually replaced with Cys. Both the F39C and L40C mutant peroxidases yield active-site disulfides involving the new Cys and the native Cys42; formation of the Cys39-Cys42 disulfide, however, precludes binding of the FAD coenzyme. In contrast, the L40C mutant contains tightly-bound FAD and has been analyzed by both kinetic and spectroscopic approaches. In addition, the L40C and S41C mutant structures have been determined at 2.1 and 2.0 A resolution, respectively, by X-ray crystallography. Formation of the Cys40-Cys42 disulfide bond requires a movement of Cys42-SG to a new position 5.9 A from the flavin-C(4a) position; this is consistent with the inability of the new disulfide to function as a redox center in concert with the flavin. Stereochemical constraints prohibit formation of the Cys41-Cys42 disulfide in the latter mutant.

Measurement of surgical costs: a clinical analysis

Because of reduced health care funding it is becoming necessary for surgeons to take a greater interest in the costs of individual operations. This study reports costs directly measurable to the patient, and also the indirect costs of hospital overheads, an operating suite and teaching, which were 37, 10 and 15%, respectively (62%), of hospital budget. A scheme has been developed which could give surgeons a standard to report direct costs. Pre-admission, ward, operating room, recovery, intensive care and post-admission are defined as cost periods and the modalities of staff, equipment (capital, maintenance and replacement), imaging, laboratory and consumables apply to each. This strategy was applied to assess open cholecystectomy (OC) and laparoscopic cholecystectomy (LC) as an example. The direct costs for OC were $3706 and LC $2868, a difference of $838; the indirect and direct costs were OC $6004 and LC $4646, a difference of $1358. Thus indirect cost magnified the difference between the operations. Bed stay, density of nursing and use of disposable instruments were the major influence on direct costs. The individual cost advantage of a shorter bed stay may be countervailed by an increased hospital activity. The main patient benefit of new operations may be improved quality of life and more rapid return to work with prevention of salary losses. A method has been developed to define costs of a particular surgical operation with the purpose of stimulating surgeons' interest in this topic and developing a common style of reporting.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of a 3'-->5'-exonuclease that removes cytosine arabinoside monophosphate from 3' termini of DNA

Cytosine arabinoside monophosphate (araCMP) at the 3' terminus of DNA constitutes a lesion that impedes further synthesis by DNA polymerase alpha (DNA pol alpha). A biochemical assay has been designed to detect 3'-->5'-exonucleases in cell extracts that remove the 3'-araCMP lesion in an oligonucleotide template-primer and permit subsequent extension by DNA pol alpha. The major 3'-->5'-exonuclease activity in human myeloblast extracts has been purified, and gel filtration chromatography of the purified enzyme indicates that the exonuclease has an apparent native molecular mass of 52 kDa. Incubation of the enzyme with a 5'-32P-labeled araCMP template-primer results in exonucleolytic degradation of the primer exclusively in the 3'-->5' direction, demonstrating that the enzyme is a 3'-->5'-exonuclease. The products of the 3'-->5'-exonuclease reaction are 5'-mononucleotides. The apparent rate of araCMP removal by the exonuclease is approximately the same as the rate of deoxynucleoside monophosphate (dNMP) removal. Furthermore, the apparent rates of 3'-terminal excision are approximately the same whether the oligomer is hybridized to a complementary oligonucleotide, or not, indicating that the enzyme has both single- and double-stranded 3'-->5'-exonuclease activity. The enzyme does not possess 5'-->3'-exonuclease activity, nor is it associated with DNA polymerase activity. In addition, the enzyme does not cleave 3'-phosphoryl-terminated DNA, and it does not cleave RNA. The enzymatic characteristics of the isolated 3'-->5'-exonuclease indicate that it is distinct from previously identified mammalian deoxyribonucleases.

Ontogeny of glycoprotein gB-specific antibody and neutralizing activity during natural cytomegalovirus infection

The envelope glycoprotein gB (gpUL55) is a candidate for inclusion in subunit cytomegalovirus (CMV) vaccines, although data on gB antibody responses after natural infection are limited. [35S]-labeled gB was partially purified from cells infected with an adenovirus recombinant expressing gB and used in radioimmunoprecipitation assays to characterize responses in solid organ transplant recipients with primary (n = 11) or secondary (n = 8) CMV infection. Seropositive transplant patients without evidence of infection (n = 5) and healthy seroconverters (n = 7) were also studied. gB antibody developed concurrently with CMV-specific IgG, IgM, and neutralizing activity in transplant patients with primary infection. Sustained boosts in gB antibody were seen in patients with secondary infection, and healthy seroconverters developed early gB responses. These data imply that gB antibody is an integral part of the humoral response to CMV infection, and, in view of experimental data regarding immunogenicity, support a role for gB in subunit vaccines.

IL-6 mediated isotype specific suppression of hapten specific IgE in serum of BPO-KLH sensitized mice: role of IFN alpha in maintainance of hapten specific IgE responses

The ability of IL-6 or IFN alpha or antibodies to these cytokines to regulate serum levels of hapten specific immunoglobulins (IgM, IgG1, IgE, IgA) was studied in BPO-KLH (benzylpenicilloyl-keyhole limpet hemocyanin) sensitized BALB/c mice at the peak of a hapten specific IgE antibody forming cell (AFC) response. To induce peak IgE responses, mice were injected intraperitonealy (i.p.) with BPO-KLH (10 micrograms) in aluminum hydroxide gel (alum) on days 0, 21, and 42. On day 44, mice were injected s.c. with IL-6 (100-1000 U), IFN alpha (1000-10,000 U), anti-IL-6 (100-1000 neutralizing units [NU]), or anti-IFN alpha (1000-10,000 NU). On day 46, levels of BPO specific IgM, IgG1, IgE and IgA in serum were determined (ELISA). Data are expressed as micrograms/ml. IL-6 suppressed BPO specific IgE in serum in isotype specific fashion (to > 90%), increasing IgA (approximately 3 fold), and leaving IgM and IgG1 unchanged. Since removal of endogenous IL-6 with anti-IL-6 increased serum IgE, and suppressed IgG1 (approximately 50%), with IgM and IgA unchanged, this suggests that IL-6 is an isotype specific suppressor of peak IgE responses and as such may be useful in the therapeutic management of atopic disease. IFN alpha treatment increased serum IgE levels (60%), and potentiated IgA responses (> 30 fold), with IgM and IgG1 unchanged. Since removal of endogenous IFN alpha with anti-IFN alpha decreased IgE levels (approximately 50%), increasing IgA, with IgM and IgG1 unchanged, this suggests a role for IFN alpha as an isotype specific helper of peak IgE responses and in maintenance of IgA responses.

The use of random-breakage mapping to locate the genes APN1 and YUH1 in the Saccharomyces genome, and to determine gene order near the left end of chromosome XI

We have used the previously described technique of random-breakage mapping to locate the two yeast genes APN1 and YUH1. The APN1 locus is located approximately 235 kb from the left telomere of chromosome XI, and shows weak (approximately 53 cM) genetic linkage to ura1. The YUH1 locus is located approximately 140 kb from the right telomere of chromosome X, and genetically maps 3.6 cM distal to cdc11. In addition, we show by random-breakage mapping that TRP3 is located approximately 45 kb from the left telomere of chromosome XI, whereas FAS1 is approximately 110 kb from the same telomere. This supports a gene order on the left distal portion of chromosome XI that agrees with other physical reports but is inverted with respect to Edition 11 of the published genetic map. This report confirms that random-breakage mapping is a rapid and convenient method of locating cloned genes.

Improvements to the differential display method for gene analysis

Differential display requires two primers to identify discordantly expressed mRNAs. Anchored primers with at least one G residue were superior to those which had one C residue and those ending in A or T were the least efficient. Arbitrary primers with GC pairs at the 5'end were superior to primers with GC pairs at the 3'end. We found that screening of amplified DNA-fixed membranes by a slot blot manifold and hybridization with DNA probes made from sample RNA rapidly re-screened with DNA fragments for differential expression, requires less RNA and is faster than Northern analysis. Similarly, hybridization of DNA fragments to plasmid DNA fixed to membranes and direct PCR sequencing rapidly determine homology to common laboratory plasmids prior to any further manipulation. These modifications permit rapid isolation and characterization of DNA fragments identified by differential display.

An evaluation of laparoscopic versus open cholecystectomy

OBJECTIVE

To compare open cholecystectomy (OC) with laparoscopic cholecystectomy (LC) in terms of clinical aspects and a limited review of costs.

SETTING

The Austin Hospital, Melbourne, a university teaching hospital.

DESIGN

Prospective LC patients were compared with a retrospective group of OC patients whose surgery had been performed by the same surgeons.

METHODS

Consecutive patients undergoing LC were interviewed, their medical records were analysed and the cost of their hospitalisation was assessed. Similar data, collected previously from patients undergoing OC, were used for comparison.

RESULTS

There were 108 patients in each group, 93.5% treated electively. All had gallstones. No deaths or common bile duct injury occurred. The mean operating room time was 131 +/- 3.7 minutes for OC and 164 +/- 4.7 minutes for LC. Operative cholangiography was attempted in 80% in each group, being successful when attempted in all OCs and in 95% of LCs. The conversion rate of LCs to OCs was 4.5%. Minor complications were more frequent with OCs. The mean duration of hospital stay was 6.5 +/- 0.3 days for OCs and 2.0 +/- 0.2 days for LCs. The amount and period of analgesia were significantly less in the LC group. Patients recovered significantly faster after LC (P < 0.01) during the first eight weeks after surgery. There was no difference by 12 weeks. The overall cost for each LC was $838 less than OC for the entire hospital stay.

CONCLUSION

These results support the view that LC is a safe and justified replacement for OC in the elective situation, with benefits to the patient, hospital and general community. The hospital cost for LC was less than for OC.

Comparative flow rates of saline in commonly used spinal needles including pencil-tip needles

BACKGROUND AND OBJECTIVES

Certain characteristics of spinal needles that can influence their clinical usefulness were examined, namely, flow rates, internal diameters, and size of orifices of pencil-type needles.

METHODS

Flow rates of 0.9% sodium chloride solution were measured in spinal needles with an infusion pressure of 10 mmHg at isothermic and steady-state conditions. In 15 different types, a new needle was used for each experiment, and 6 experiments were performed with each needle type for a total of 90 experiments. The Hagen-Poisseuille Law for laminar flow was used to calculate the internal diameters.

RESULTS

The flow rates of needles of the same gauge varied considerably depending on the manufacturer. Compared with 26-gauge ultrathin-wall spinal needle produced by the same manufacturer (Braun, Bethlehem, Pennsylvania), the flow rate through 29-gauge spinal needle was 18% that of the former needle. The flow rate through 27-gauge Quincke Whitacre needle (Becton Dickinson, Rutherford, New Jersey) was not statistically different from that through 26-gauge needle by the same manufacturer. By arbitrarily choosing < or = 2 seconds to be the in vitro desirable period for saline to traverse the needle from one end to the other, all needles with the exception of 29-gauge and standard 26-gauge Quincke Braun needles met this criterion. The length and size of the orifices of Whitacre needles were found to be significantly smaller than those of Sprotte needles (Havel, Cincinnati, Ohio). The orifice of Sprotte needle was longer than the known thickness of the dura while that of the Whitacre needle was smaller.

CONCLUSIONS

Needles of the same gauge do not necessarily have the same flow rate. Flow rate correlates well with internal, not external, diameter. By considering < or = 2 seconds to be the desirable time for saline to traverse a spinal needle, all, except two, meet this criterion. The orifice of Whitacre needle has more desirable features than that of Sprottle needle. Anesthesiologists are encouraged to use 27-gauge needles since their flow rate is not slower than that of 26-gauge needles.

LIF and OM directly interact with a soluble form of gp130, the IL-6 receptor signal transducing subunit

Oncostatin M and LIF are related members of a cytokine family that also includes IL-6, CNTF and G-CSF. These proteins exhibit overlapping biological properties and with the exception of G-CSF, they all appear to utilize gp130 as a signaling component of their high affinity receptor complexes. Recently it has been demonstrated that monomeric, membrane bound gp130 can directly bind OM. To further investigate the binding properties of gp130 we generated a soluble form of gp130, sgp130-Rg, to investigate potential gp130 interactions with OM and other members of this cytokine family. Using chemical crosslinking techniques we demonstrate that OM and LIF but not CNTF or IL-6 directly interact with sgp130-Rg. Since OM signaling can be prevented by binding gp130 with anti gp130 mAbs we also investigated the potential of sgp130-Rg to prevent the biological activities of both LIF and OM. Here we demonstrate that sgp130-Rg can bind LIF and OM preventing their biological activities on the TF-1 erythroleukemia cell line. This property suggests that sgp130-Rg may have therapeutic value in the specific prevention of LIF or OM mediated pathologies.

Protein-sulfenic acid stabilization and function in enzyme catalysis and gene regulation

Sulfenic acids (R-SOH) result from the stoichiometric oxidations of thiols with mild oxidants such as H2O2; in solution, however, these derivatives accumulate only transiently due to rapid self-condensation reactions, further oxidations to the sulfinic and/or sulfonic acids, and reactions with nucleophiles such as R-SH. In contrast, oxidations of cysteinyl side chains in proteins, where disulfide bond formation can be prevented and where the reactivity of the nascent cysteine-sulfenic acid (Cys-SOH) can be controlled, have previously been shown to yield stable active-site Cys-SOH derivatives of papain and glyceraldehyde-3-phosphate dehydrogenase. More recently, however, functional Cys-SOH residues have been identified in the native oxidized forms of the FAD-containing NADH peroxidase and NADH oxidase from Streptococcus faecalis; these two proteins constitute a new class within the flavoprotein disulfide reductase family. In addition, Cys-SOH derivatives have been suggested to play important roles in redox regulation of the DNA-binding activities of transcription factors such as Fos and Jun, OxyR, and bovine papillomavirus type 1 E2 protein. Structural inferences for the stabilization of protein-sulfenic acids, drawn from the refined 2.16-A structure of the streptococcal NADH peroxidase, provide a molecular basis for understanding the proposed redox functions of these novel cofactors in both enzyme catalysis and transcriptional regulation.

Diagnostic strategies in the management of acute upper gastrointestinal bleeding: patient and physician preferences

BACKGROUND

Routine diagnostic endoscopy is commonly obtained for low-risk patients with acute upper gastrointestinal bleeding despite evidence from controlled trials that it does not improve patient outcome.

OBJECTIVE

To determine whether endoscopy is being overutilized for these patients or whether considerations not addressed in the trials could justify its widespread use.

METHODS

Twenty-five patients recovering from a recent hemorrhage and 22 primary care physicians used the analytic hierarchy process to perform an individualized analysis regarding the diagnostic management of acute upper gastrointestinal bleeding. The results were used to determine whether routine endoscopy was consistent with each subject's interpretation of relevant data and judgments regarding the relative importance of five management goals. The authors then compared the proportion of subjects in each group who preferred endoscopy over two non-endoscopy strategies (upper gastrointestinal series and no routine diagnostic test) with 85%, the current rate of endoscopy at the authors' hospital.

RESULTS

Endoscopy was preferred by 92% (97.5% CI: 70%-98%) of the patients and 55% (97.5% CI: 31%-77%) of the physicians. The patients ranked identifying the cause of bleeding the second most important management goal after avoiding a poor outcome from the acute bleeding episode.

CONCLUSIONS

The current rate of diagnostic endoscopy is higher than would be expected based on physicians' preferences but quite consistent with patients' preferences. Patients regard knowledge of the bleeding site as important, even if this information will not affect management or prognosis. Attempts to assess the use of diagnostic endoscopy and other diagnostic tests should take both patient preferences and the pure value of diagnostic information into account.

Porphyrin profiles in the nestling European starling (Sturnus vulgaris): a potential biomarker of field contaminant exposure

Porphyrin patterns in avian and mammalian tissues and/or excreta have been proposed as qualitative and quantitative biomarkers of exposure to polyhalogenated hydrocarbons, heavy metals, and other environmental contaminants. However, no widely distributed terrestrial species has been characterized as a suitable model in which to assess porphyrin profiles in the evaluation of environmental contaminant exposure. The European starling, whose nests can be readily established and manipulated on contaminated sites, has many qualities that accommodate controlled field research and that suggest its suitability for such assessments. In the present studies, we measured the total and individual porphyrin concentrations in liver, kidney, and fecal-urate excreta of nestling starlings from a noncontaminated field site from day of hatch through d 17 of the nestling period. Total as well as individual 8-, 7-, 6-, 5-, 4-, and 2-carboxyl porphyrin concentrations in liver, kidney, and fecal-urate excreta were readily detectable by high-performance liquid chromatography (HPLC) spectrofluorometric techniques and displayed tissue-specific patterns throughout the developmental period. Liver and fecal-urate porphyrin patterns were established by d 4 subsequent to hatch and remained constant through d 17 of development, whereas renal porphyrin profiles were constant throughout the entire developmental period. In controlled field studies, nestling starlings were treated with either HgCl2 or hexachlorobenzene (HCB), and tissue and excreta porphyrins were extracted and evaluated. The findings suggest that the nestling starling may serve as a suitable model species in which to monitor the effects of field contaminant exposure to wildlife based on chemical-induced changes in tissue or excreta porphyrin levels.

Drama: a medium to enhance social interaction between students with and without mental retardation

Twenty-four fifth grade (or equivalent age) students were assigned to one of two treatment conditions consisting of equal numbers of students from regular and special education classes. One group was involved in a dramatic games condition culminating in a theatrical performance planned by the group. The second group was involved in a noncompetitive games condition culminating in a demonstration of games developed by the group. Observational data recording initiations and receptions of prosocial bids were collected for all subjects receiving special education services within both groups. A sociometric measure was used to assess the perceived quality of friendships both before and after the interventions. Results showed that students with mental retardation in the drama condition were targeted for positive social interactions by peers without mental retardation significantly more and were more highly regarded as friends than were those in the games condition.

Localization of rat tryptase to a subset of the connective tissue type of mast cell

We examined the cellular distribution of rat tryptase in rat skin, lung, small intestine, and peritoneal lavage cells by immunohistochemical techniques. Tryptase purified to apparent homogeneity from rat skin was used to generate a goat polyclonal anti-rat tryptase antibody. Tryptase-containing cells were detected in lung, skin, and peritoneal lavage cells. Small intestine mucosa, on the other hand, showed few if any tryptase-positive cells. Sequential staining with Alcian blue and anti-tryptase antibody showed that tryptase is located only in mast cells. Sequential staining with safranin to identify the connective tissue type of mast cell and anti-tryptase antibody showed that tryptase resides only in this mast cell type. However, only a subpopulation of the safranin-stained mast cells contained tryptase. In lung, 53% of the mast cells stained with safranin; 94% contained tryptase. In skin, 80% stained with safranin; only 6% contained tryptase. In peritoneal cells, more than 95% of the mast cells were stained with safranin; 20% contained tryptase. In the bowel mucosa, where few cells are stained by safranin, no cells with tryptase were detected. The percentages of cells with chymase I that also contained tryptase were 80% and 84% for lung, 4% and 7% for skin, and 15% and 13% for peritoneal cells by respective simultaneous and sequential double labeling with anti-tryptase and anti-chymase I antibodies. This study suggests that the rat connective tissue type of mast cell is subdivided into two forms on the basis of the presence or absence of tryptase, whereas rat mucosal mast cells lack this enzyme. These results contrast with those in humans, in which tryptase is present in all mast cells, but are similar to mice, in which tryptase mRNA has been detected only in the connective tissue type.

Photodynamic therapy of subretinal neovascularization in the monkey eye

Experimental subretinal neovascularization in the monkey eye was treated by photodynamic therapy with rose bengal. Following intravenous injection of rose bengal, the subretinal vessels were irradiated with filtered light. Successful treatment was achieved, provided the subretinal vessels were irradiated during the period in which the dye was present in and around the subretinal vessels but had already cleared from the retinal vasculature. The successfully treated lesions demonstrated replacement of the leaking and pooling subretinal vessels with a non-leaky scar. Morphologic evaluation revealed immediate destruction of the subretinal plexus, with minimal damage to the overlying retina. The destroyed subretinal tuft was replaced by a scar containing mainly fibroblasts embedded in collagen fibers. Our results suggest that photodynamic therapy is potentially useful for destruction of subretinal vessels without damaging the overlying retina.

Comparison of the VIDAS RSV assay and the Abbott Testpack RSV with direct immunofluorescence for detection of respiratory syncytial virus in nasopharyngeal aspirates

The sensitivity and accuracy of the VIDAS RSV assay in testing fresh specimens were 82.7 and 87.1%, respectively, whereas specimens previously frozen at -70 degrees C gave a sensitivity of 96.2% and an accuracy of 95.4%. The sensitivity and accuracy of Abbott Testpack RSV were 92.6 and 91.3% for fresh specimens and 86.8 and 88.1% for frozen specimens. The advantages and drawbacks of the two assays are discussed.

The development of outpatient prospective payment systems and the use of ambulatory patient groups by private insurers

Private insurers will likely move to APGs rapidly because of the key advantages that APGs provide. Not only is it necessary to have an outpatient classification system to make utilization review, quality assurance, and customer reporting more meaningful, outpatient prospective payment provides a foundation for the controls on outpatient payments that insurers have been seeking. Because of outpatient volume increases and constraints on inpatient payments that have led hospitals to increase outpatient charges more rapidly, most insurers believe that outpatient payment levels are currently beyond their control. Introduction of an outpatient prospective payment system will shift control over outpatient payment increases from providers to insurers, as has been the case for many insurers who have adopted DRG payment for inpatient services. Once APGs are in place, annual increases in payment amounts will be determined through insurer-provider negotiation or through contractual approaches that limit payment increases to changes in a price index.

Post-ictal psychosis after right temporal lobectomy

Of 298 patients who had temporal lobectomies for intractable epilepsy, 4 (1.3%) developed post-ictal psychosis for the first time after surgery. All were males of normal intelligence with no pre-operative psychiatric disorder. Psychosis followed both complex partial and generalised seizures. The psychotic symptoms showed polymorphic features. Right temporal lobectomy may increase the susceptibility to post-ictal psychosis in patients who are not seizure free after surgery, particularly in the first post-operative year.

Purification and analysis of streptococcal NADH peroxidase expressed in Escherichia coli

Using the T7 RNA polymerase expression system, a modified plasmid vector has been developed which gives reliable, high level expression in Escherichia coli of the gene encoding streptococcal NADH peroxidase. The recombinant enzyme has been purified to homogeneity using a revised protocol which yields over 35 mg of pure protein per liter of culture. Recombinant NADH peroxidase is fully active and exhibits spectroscopic and redox properties identical to those for the enzyme purified from Streptococcus faecalis 10C1. Reductive titrations and thiol analyses confirm the presence of the unusual cysteine-sulfenic acid (Cys-SOH) redox center identified previously. N-terminal sequence analysis, analytical gel filtration, and preliminary x-ray diffraction data all confirm the structural identity of the recombinant and S. faecalis enzymes. Steady-state kinetic analysis of the peroxidase, coupled with results from static titration experiments is consistent with a limiting type of ternary complex mechanism and allows the determination of many of the corresponding kinetic constants. In addition, preliminary 1H NMR spectra of the enzyme at millimolar concentrations show good dispersion in the amide region and indicate that the recombinant peroxidase is suitable for one-dimensional NMR work with labeled amino acids.

Primary generalized seizure disorder: correlation of epileptiform discharges with seizure frequency

The role of routine follow-up EEG in assessment of severity of a seizure disorder is not known. This retrospective chart review study of patients with primary generalized seizure disorders explored the relation between parameters of epileptiform discharge bursts on EEG and number of seizures experienced in the preceding months. Eighty-seven such patients were found, each with one to seven EEGs and corresponding clinical records, comprising a total of 201 clinicoelectrographic epochs. The 56 chronically attending patients (more than two attendances) differed from the 31 nonchronic attenders in receiving more antiepileptic drugs (AEDs) and having fewer EEG polyspikes; otherwise, the two groups were similar and were analyzed together. We noted a strong relation between number and maximum length of epileptiform bursts in the resting EEG record and number of absence seizures reported in the months preceding the EEG. Age did not affect this relation. After stepdown regression analysis, only the maximum length of epileptiform bursts remained significantly related to the reported number of absence seizures. These findings may prove useful in assessing clinical progress, e.g., in patients whose ability to estimate numbers of attacks is suspect. Neither number nor maximum length of epileptiform bursts in the resting EEG record had a significant relation with the number of generalized tonic-clonic seizures. Presence of polyspikes on resting or "activated" EEG had no added predictive value. The presence of epileptiform bursts after activation by sleep, hyperventilation, or photic stimulation was not associated with an increased likelihood of having had seizures.

Comparison of immunological reactivity to two major antigens of homologous and AD169 human cytomegalovirus strains during primary infection in renal transplant patients

The IgG and IgM immunoblotting patterns for the major HCMV antigens p65 and p55/52 were studied in 5 renal transplant recipients during primary HCMV infections. Sequential sera from the 5 patients were tested in parallel with standardized antigens derived from the reference strain AD169 and from the patient'own isolates. The immunoblotting patterns differed from patient to patient as well as between strain AD169 and the patient's homologous isolates. The differences consisted in a better response to the antigens derived from the reference strain AD169, suggesting a delay of the IgM/IgG switch and of the affinity maturation of IgG antibodies to the homologous p65 and p55/52 antigens. The results suggest caution in the interpretation of immunoblotting data derived from laboratory strains such as AD169.

Asymmetrical cognitive differences associated with hemiparkinsonism

The question of whether Parkinson's disease (PD) patients who have left (LPD) or right (RPD) motor predominance also exhibit cognitive differences is controversial. We examined this issue using a neuropsychological battery designed to provide a balanced sampling of both right- and left-hemispheric functions. RPD patients were impaired relative to LPD patients on verbally mediated tasks (left hemisphere function), but there was no group difference for visuospatial tasks (right-hemispheric function). In addition, there was a significant correlation between the extent of right side motor predominance and performance on verbal tasks, but there was no relationship between left side motor symptoms and performance on visuospatial tasks. The controversy related to cognitive differences in hemiparkinsonism may be due to the balance of the assessment procedure, the severity of motor asymmetry, or both.

Intraosseous infusion of resuscitative fluids and drugs: long-term effect on linear bone growth in pigs

We studied the effects of intraosseous (IO) infusion of a standard fluid bolus and resuscitative drugs on long-term bone growth and epiphyseal closure in the "pediatric" swine model. Eighteen weanling pigs were randomly assigned to six groups as follows: three animals received two normal saline boluses, 20 mL/kg IO over 20 minutes; three received sodium bicarbonate, 1 mEq/kg IO; three received a 10% sodium bicarbonate infusion IO at maintenance rate over 1 hour; three received epinephrine 1:10,000, 0.1 mL/kg IO; three received an epinephrine infusion IO at 1 microgram/kg/min for 1 hour; and three received a dopamine infusion IO at 10 micrograms/kg/min for 1 hour. All infusions were given in the left hindleg; the right hindleg was used as a control. Lateral radiographs of the hind extremities were obtained at the beginning of the study and at 1 and 3 months after infusion. Linear radiographic measurements of the infused and control tibias were compared. At 6 months after infusion, the tibias were harvested, measured directly, and radiographed to determine the degree of epiphyseal closure. Analysis of variance for the first 3 months' data yielded a nonsignificant time-by-treatment interaction (P = .84) and a nonsignificant main effect for time (P = .22). Separate analysis of the direct measurements taken at 6 months revealed no difference in growth between experimental and control tibias. In addition, no radiographic difference in epiphyseal closure was noted between the two groups at the conclusion of the study, nor were any structural defects discovered. Intraosseous infusion of fluids and resuscitative drugs does not adversely affect subsequent bone growth and development in the swine model.

Effect of subarachnoid morphine on the incidence of spinal headache

BACKGROUND AND OBJECTIVES

The addition of fentanyl to hyperbaric local anesthetics has been shown to reduce the incidence of post dural puncture headache in the obstetric patient. This study was undertaken to evaluate the effects of subarachnoid morphine on the incidence of headache.

METHODS

Eighty-two healthy patients undergoing cesarean delivery with spinal anesthesia were studied. All patients were hydrated with 1500 ml lactated Ringer's solution. Patients were randomly assigned to receive, in a double-blind fashion, 0.2 mg of either morphine (Group 1, n = 40) or saline (Group 2, n = 42) in 0.2 ml volume mixed with 0.75% bupivacaine in 8.25% dextrose plus 0.2 ml 1:1000 epinephrine. Spinal anesthesia was induced using a 25-gauge spinal needle at L3-4 interspace with the bevel, in most cases, parallel to the dural fibers. Patients were followed for three days to evaluate the incidence and severity of headache using a four-category rank scale (none, mild, moderate, severe). Data were analyzed for statistical significance using Student's t-test or chi-square test as appropriate. A p value less than 0.05 was considered significant. Results. The incidence of post dural puncture headache did not differ significantly between groups. Eight patients in Group 1 versus nine patients in Group 2 developed headache (p greater than 0.05). Similarly, the use of blood patch or intravenous caffeine sodium benzoate to treat the headache did not differ significantly between groups.

CONCLUSION

It is concluded from our study that subarachnoid morphine did not decrease the incidence of post dural puncture headache in the obstetric patient.

New monoclonal antibodies for the detection of immediate early antigens of cytomegalovirus

Two new monoclonal antibodies, CIE-1 and CIE-2, were developed for the rapid detection of human cytomegalovirus (HCMV) infection. They were found to be reactive with immediate early protein of HCMV in the nuclei of infected fibroblasts, as early as 3 hours post-infection. By radioimmunoprecipitation, CIE-1 was found to react with a protein with an apparent molecular weight of 70,000, whereas CIE-2 precipitated 2 proteins of 70,000 and 72,000 daltons, respectively. Both monoclonal antibodies recognized three prototype strains of HCMV: AD-169, Towne, and Davis, and did not cross-react with other human herpesviruses. CIE-1 and CIE-2 were compared with four commercial anti-HCMV monoclonal antibodies (Clonab, Dupont, Sera-Lab and Syva) by testing 88 clinical isolates. Culture confirmation tests and shell vial assays showed that CIE-1 and CIE-2 were more sensitive than several of these reagents and equally sensitive to the Dupont reagent. Moreover, CIE-1 and CIE-2 produced a bright, sharp staining of the nuclei of infected cells. These monoclonal antibodies should thus be valuable in rapid diagnosis of HCMV.

Peroxide modification of monoalkylated glutathione reductase. Stabilization of an active-site cysteine-sulfenic acid

Hydrogen peroxide reacts with two-electron reduced glutathione reductase (GR EH2 species) to give the native oxidized enzyme (E) without detectable intermediates. Prior alkylation of the EH2 interchange thiol with iodoacetamide, however, dramatically changes both the course and overall rate of the peroxide reaction. This oxidation, monitored spectrally, is characterized by an intermediate (EHRint) with enhanced long wavelength absorbance extending to 800 nm. This species decays in a second peroxide-dependent phase to an enzyme form (EHRox) easily distinguished from E. Quenching experiments with catalase allow the isolation of a stable mixture consisting of 36% monoalkylated GR (EHR), 60% EHRint, and 4% EHRox; NADPH titration and anaerobic dithiothreitol addition lead to quantitative reduction of EHRint to EHR, and there is an increase in thiol titer of 0.8-SH/FAD on NADPH reduction. Of the four titratable thiols present in EHR, 2.7 are lost on oxidation to EHRox and 0.7-0.8 mol of cysteic acid/FAD is formed. On the basis of these and other observations, we conclude that alkylation of the EH2 interchange thiol, which blocks disulfide formation, allows peroxide reaction at the remaining charge-transfer thiol to proceed via a stabilized cysteine-sulfenic acid intermediate (EHRint), which undergoes further oxidation to the corresponding cysteic acid (EHRox).

Comparison of immunofluorescence and enzyme immunoassay for detection of measles-specific immunoglobulin M antibody

During a measles outbreak, 283 serum specimens from 221 suspected cases of measles were tested by immunofluorescence and enzyme immunoassay for the presence of measles-specific immunoglobulin M (IgM) antibodies by using commercially available reagents. There was 97% agreement between the two assays; thus, the choice of the method for diagnostic testing is a matter of convenience and experience. In all 62 cases of measles from which a single blood sample was available, measles IgM-specific antibodies were detectable by both methods. Fifty percent of the 62 cases were positive within 3 days after onset of the rash. This increased to 91% 10 days after onset of the rash.

Prospective study of cytomegalovirus antigenemia in allograft recipients

A recently published technique for direct detection of cytomegalovirus (CMV) antigenemia was tested prospectively in 27 transplant recipients. Eighteen patients developed active CMV infections and 10 of the 18 experienced CMV syndrome. All of the infections were detected by classical virus isolation and/or serologic techniques. No antigenemia was demonstrated.

Isradipine: overall clinical experience in hypertension in the United States

Isradipine is a new dihydropyridine calcium antagonist shown to be efficacious, safe, and well tolerated in the treatment of hypertension, regardless of patient age or race. There has been no evidence of negative inotropism, atrioventricular conduction delay, nor clinically significant changes in laboratory parameters associated with isradipine treatment. A total of 934 patients have been treated with isradipine in double-blind hypertension trials (involving 297 patients treated with placebo and 414 treated with active controls, such as hydrochlorothiazide and enalapril). Both the mean changes from baseline in diastolic and systolic blood pressures and the percentage of patients responding to treatment (blood pressure decrease of at least 10 mm Hg) were greater with isradipine than with placebo or active controls. Blood pressure response increases with increases in isradipine dose up to 10 to 15 mg daily; higher doses do not, on average, result in greater blood pressure reduction. The incidence of adverse reactions with isradipine is similar to that for active controls and slightly more than for placebo. There were fewer discontinuations with isradipine and, in addition, a decrease in the incidence of new adverse reactions with increasing duration of treatment, down to 1% at 24 months.

Blunt liver trauma at sunnybrook Medical Centre: a 13 year experience

Between June 1, 1976 and June 30, 1989 The Regional Trauma Unit at Sunnybrook Medical Centre in Toronto, Ontario, Canada received 3730 patients. Of these 335 (9%) sustained a liver injury, 95% being due to blunt trauma. Open peritoneal lavage was performed on 80% of liver trauma patients (267/335), 99% being true positive. A laparotomy was performed on 97% of patients (324/335). Major surgical treatment was required in 132 patients (41%) and minor treatment in 192 patients (59%). The remaining 11 patients were treated conservatively (n = 3) or died during resuscitation (n = 8). Morbidity directly related to the liver injury was seen in 29 of 249 surviving patients (11%) although overall morbidity was 27% (67/249). Reoperation was required in 6% (14/249) with abscess or hematoma accounting for 11 of 14 operations. The overall mortality rate was 26% (86/335). Eighty two percent of patients (n = 276) had a grade I, II or III liver trauma according to Moore's classification with a mortality of 12% (n = 32). The remaining 18% of patients (n = 59) had a grade IV or V liver trauma with a mortality of 44% (n = 26). Of the 86 deaths, head injury accounted for 48 (56% of deaths); liver hemorrhage for 17 (20%), liver sepsis for 1 (1%) and other causes for 20 deaths (23%). Thus death due to the liver injury itself (hemorrhage and sepsis) occurred in 18 out of 335 patients (5% overall). Head injury accounted for the death of 48 out of 335 patients (14% overall). Over the past 13 years a trend has occurred at our institution whereby we are seeing less liver trauma in our population of multiply injured patients from 12% (1976-1983) down to 7% (1985-1989); with a gradual decline in overall mortality from 32% (1976-1983) to 19% (1985-1989), whereas the percentage of deaths due to head injuries and liver injury have increased.

Heterogeneity among the flavin-containing NADH peroxidases of group D streptococci. Analysis of the enzyme from Streptococcus faecalis ATCC 9790

Polyclonal antisera prepared against the purified NADH peroxidase from Streptococcus faecalis ATCC 9790 (Enterococcus hirae) do not cross-react with the ATCC 11700 enzyme. Comparative tryptic maps of the two proteins indicate that the differences in primary structures extend beyond those localized to respective antigenic epitopes. Alignments of the NH2-terminal and active-site cysteinyl peptide sequences of the two streptococcal peroxidases reveal identities of 50 and 67% in the respective overlap regions. Dithionite titrations of the ATCC 9790 enzyme reveal a separation in potentials (E2 - E1) for the nonflavin and flavin redox centers of 39 mV, a value nearly 50 mV lower than that observed with the ATCC 11700 peroxidase. Despite these changes in redox behavior NADH titrations of the ATCC 9790 enzyme give rise to both EH2 and EH2.NADH species as previously observed. The enzyme turnover number with hydrogen peroxide is approximately 60% that of the ATCC 11700 peroxidase; the ATCC 9790 peroxidase is also inhibited during turnover with ethyl hydroperoxide. These findings suggest that the flavoprotein NADH peroxidases may exhibit greater diversity among the group D streptococci than previously observed with the widely distributed enzymes of the related flavoprotein disulfide reductase class.

Synthetic peptide antigens elicit monoclonal and polyclonal antibodies to cytochrome P450 IA2

Two peptide sequences from cytochrome P450 IA2 were synthesized, coupled to ovalbumin and used as antigens to generate anti-peptide monoclonal and polyclonal antibodies. Antisera to both peptides reacted with rat IA2 but not the structurally similar IA1 form as determined by enzyme-linked immunosorbent assay. However, antisera to both peptides detected both rat IA2 and IA1 on immunoblots. In addition immunoblots of human liver microsomes revealed that both antisera recognized human IA2, but not IA1. Monoclonal antibodies generated against one of the peptides recognized rat IA2 and IA1 but did not detect human IA2. These results demonstrate the utility of anti-peptide antisera as a practical approach for the generation of P450 specific antibodies.

Pathogenesis of laser-induced choroidal subretinal neovascularization

The early stages (1 day to 3 weeks) in the development of laser-induced choroidal subretinal neovascularization were studied in the monkey eye. Histopathology revealed that the intense laser beam disrupted the choroid/Bruch's membrane/retinal pigment epithelium (RPE) complex and initiated a repair process. Although all lesions received the same energy density, the initial choroidal wound varied among the lesions: in some, the necrotic choroid was surrounded by hemorrhagic retinal detachment with RPE denudation; in others, the necrotic choroid was surrounded only by minimal damage to the RPE monolayer. Formation of the choroidal wound was followed by an inflammatory response. Later, newly formed choroidal tissue filled the wound and continued to proliferate towards the subretinal space. RPE cells from the edges of the wound proliferated over the newly formed subretinal tissue and closed the wound. In lesions with a large area of damaged RPE, coverage of the wound was slow; fluid accumulated in the subretinal space, and the lesions demonstrated pooling of fluorescein on angiography (leaky lesions). In lesions with minimal damage to RPE monolayer, closure of the wound was rapid, and the proliferating choroidal tissue did not reach the subretinal space. There was no subretinal fluid accumulation and no pooling of fluorescein on angiography (nonleaky lesions). Our results indicate that both the amount of damage of the choroid/Bruch's membrane/RPE complex and the ability of RPE cells around the damaged area to proliferate and restore the continuity of the RPE layer determine the evolution of newly formed choroidal fibrovascular tissue into a subretinal membrane with or without pooling.

Variation in inducibility of cytochrome P-450c and aryl hydrocarbon hydroxylase in rat liver, lung, kidney, pancreas and nasopharynx

The effect of 3-methylcholanthrene (MC) treatment on the cytochrome P-450c content of various rat tissues was examined by measuring the level of immunodetectable P-450c in conjunction with its aryl hydrocarbon hydroxylase (AHH) activity. Immunoblots revealed that P-450d was induced in the nasopharynx and pancreas in addition to its previously reported induction in the liver, lung and kidney. In contrast to P-450c, induction of the immunorelated P-450d was observed only in the liver. The specific content of immunodetected P-450c in the tissue homogenates decreased in the order: liver, nasopharynx, pancreas, lung, kidney. The corresponding AHH activities decreased in the order: liver, kidney, lung, nasopharynx, pancreas. The ratio of AHH activity to P-450c content varied widely among tissues: ratios of 37.2:1.7:0.47:0.04:0.02 were obtained for the kidney, liver, lung, nasopharynx and pancreas, respectively. The absence of a direct relationship between the levels of AHH and P-450c indicates that the extrahepatic activity may partially derive from P-450 forms other than P-450c and/or the specific activity of P-450c varies among different tissues.